College of Sciences E-newsletter

October 2008

In this issue:

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Calling All Alumni

Beginning last month, the College of Sciences E-Newsletter arrived in the electronic mailboxes of all college alumni with email addresses on file with the Alumni Relations Office.

We look forward to hearing from our alumni - near and far – and encourage you to contact us with news, information, questions, and comments. Let classmates know where you are and what you are up to. Post an inquiry to try and locate a long lost classmate. Interested in contacting a former professor, just let us know.

Let us hear from you, whether you live just down the road, across the continent, or in some exotic location.

Fenton Kay (B.S., 1967; M.S., 1969) was kind enough to provide a personal and professional update on his activities since leaving UNLV. We hope this stirs some memories and encourages you to do the same.

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Study Finds Artificial Turf May be Too Hot for Summer Use

UNLV Press Release

UNLV Impacts

Replacing natural grass with artificial turf on recreational fields and parks is a successful water conservation method that has saved municipalities across the country millions of dollars in maintenance and irrigation costs. However, a new study finds that surface temperatures on artificial turfgrass far exceed those of other surfaces, significantly limiting recreational use during the summer months.

Researchers from the University of Nevada, Las Vegas (UNLV) and the Desert Research Institute (DRI) found the maximum surface temperature of green artificial turfgrass was approximately 69 degrees F higher than that of irrigated natural grass, and 62 degrees F higher than air temperature. The study, which was conducted between August 2006 and March 2007, recorded maximum surface temperatures as high as 169 degrees F, or 46 degrees higher than what previous research has determined to be the threshold for safe extended use. What’s more, the study did not record data during the two hottest months of the year.

“Surface temperatures during the summer months could entirely preclude recreational use on artificial turfgrass during daytime hours, thereby offsetting any benefits realized by reduced irrigation,” said Dale Devitt, professor of soil and water in UNLV’s College of Sciences. “Green artificial turfgrass reacted much more quickly to solar radiation than did any other surface in our study, including concrete, asphalt, natural grass, and white artificial turfgrass.”

The researchers collected data on surface temperature, spectral reflectance, solar radiation and air temperatures associated with different landscape surfaces at a Las Vegas city park and an artificial turfgrass system at the UNLV greenhouse complex. They also monitored the amount of energy absorption and heat distribution within a test plot of artificial turfgrass installed and maintained by the City of Las Vegas Department of Park Maintenance.

The results show that the rapid increase in surface temperature of artificial turf can be attributed primarily to solar radiation as opposed to air temperature, and that a lack of heat transfer from the plastic turfgrass blades to underlying fill material was also a factor. While these findings suggest product material and construction are contributing causes for the elevated temperatures, the researchers note that the study was only conducted on one kind of artificial turfgrass and acknowledge that results might differ with other artificial turf grass products.

Devitt cautions that this study is not intended to provide a rationale against the use of artificial turfgrass, but rather a caveat to park managers who must choose from myriad products on the market. He encourages managers of recreational fields to investigate all available products before purchasing artificial turfgrass and to consider using more reflective colors to help minimize surface temperatures.

“The massive amount of water savings attributed to the use of artificial turf cannot be disputed,” said Devitt, who is also director of the UNLV Center for Urban Horticulture and Water Conservation. “This research shows that improvements to the product are critical if we are to continue using artificial turf as both a water conservation tool and as a playable surface for our parks and sporting fields.”

Michael H. Young, associate research scientist at DRI, and UNLV graduate students Malika Baghzouz and Brian Bird also contributed to the study. The study was published in Volume 83 of the Journal of Turfgrass and Sports Surface Science and was funded in part by the City of Las Vegas. Copies of the full report are available upon request.

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Earliest Animal Footprints Ever Found -- Discovered in Nevada

An Ohio State University press release highlighted a major scientific discovery presented at a poster session at the Geological Society of America meeting on October 5, 2008 in Houston, Texas. Margaret “Peg” Rees, professor of geoscience and executive director of the Public Lands Institute (PLI) is a co-author of this report.

COLUMBUS, Ohio -- The fossilized trail of an aquatic creature suggests that animals walked using legs at least 30 million years earlier than had been thought.

The tracks -- two parallel rows of small dots, each about 2 millimeters in diameter -- date back some 570 million years, to the Ediacaran period.

The Ediacaran preceded the Cambrian period, the time when most major groups of animals first evolved.

Scientists once thought that it was primarily microbes and simple multicellular animals that existed prior to the Cambrian, but that notion is changing, explained Loren Babcock, professor of earth sciences at Ohio State University.

"We keep talking about the possibility of more complex animals in the Ediacaran -- soft corals, some arthropods, and flatworms -- but the evidence has not been totally convincing," he said. "But if you find evidence, like we did, of an animal with legs -- an animal walking around -- then that makes the possibility much more likely."

Soo-Yeun Ahn, a doctoral student at Ohio State, presented the discovery in a poster session at the Geological Society of America meeting Sunday in Houston. Coauthors included Margaret Rees of the University of Nevada, Las Vegas, and J. Stewart Hollingsworth of the Institute for Cambrian Studies.

Babcock was surveying rocks in the mountains near Goldfield, Nevada, with Hollingsworth in 2000 when he found the tracks.

"This was truly an accidental discovery. We came on an outcrop that looked like it crossed the Precambrian-Cambrian boundary, so we stopped to take a look at it. We just sat down and started flipping rocks over. We were there less than an hour when I saw it."

The creature must have stepped lightly onto the soft marine sediment, because its legs only pressed shallow pinpoints into that long-ago sea bed. But when Babcock flipped over the rock containing those tracks, the low-angle sunlight cast the dots in crisp shadow.

He immediately suspected that the tracks were made by an arthropod, such as one resembling a centipede or millipede, or by a leg-bearing worm.

He couldn't be certain of the length of the creature, or the number of legs it had. But judging from the tracks, he guessed that it carried its centimeter-wide body on many spindly legs.

In 2002, other researchers reported a similar fossil trail from Canada that dated back to the middle of the Cambrian period, about 520 million years ago. Another set of tracks found in South China date back to 540 million years ago.

At approximately 570 million years old, this new fossil not only provides the earliest suggestion of animals walking on legs, but it also shows that complex animals were alive on earth before the Cambrian.

Not many macroscopic fossils exist from that time because soft-bodied creatures are not normally preserved.

Babcock is an expert in "exceptional preservation" -- the special chemical, physical and biologic conditions that enabled some soft-bodied creatures to fossilize. By knowing where to look in the geologic record, he has uncovered a menagerie of unusual fossils, from unusual echinoderms in Nevada to sulfur-eating bacteria in Antarctica.

The shallow sea covering western Nevada 570 million years ago would have been a good site for exceptional preservation. The sediment surface was probably bound together by a microbial mat -- a cohesive carpet of bacteria and sediment grains. A creature's tracks could have been readily preserved when the animal pressed its legs into the sediment.

Babcock says that he is "reasonably certain -- not 100 percent" that the fossil was made by a centipede-like arthropod or a leg-bearing worm. A fossil of the animal itself would be more definitive. He is going to continue looking in the same region of Nevada, but that is not the only potential site. Similar fossils might be found in the White Sea area of Russia, South Australia, Newfoundland or Namibia, where body fossils of Ediacaran organisms have been found.

"I expect that there will be a lot of skepticism," he said about the discovery. "There should be. But I think it will cause some excitement. And it will probably cause some people to look harder at the rocks they already have. Sometimes it's just a matter of thinking differently about the same specimen."

Science News also reported these findings: http://www.sciencedaily.com/releases/2008/10/081005121337.ht

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Researchers Discover That Growing Up Too Fast May Mean Dying Young In Honey Bees

The American Physiological Society (APS) released this announcement in concert with the recent APS Conference,” The Integrative Biology of Exercise V,” held September 24-27, 2008 in Hilton Head, South Carolina.

Hilton Head, SC–Reactive oxygen species (ROS) occur as a by-product of aerobic metabolism and impair cellular function by damaging proteins, nucleotides and lipids. Organisms possess a variety of anti-oxidant mechanisms to mitigate the effects of ROS, and the oxidative stress model of aging and senescence suggests that physiological performance declines with age due to lifetime accrual of ROS-induced damage and progressively limited anti-oxidant capacity. Hence, the onset, pace and duration of energetically-intense behaviors should affect lifetime kinetics of ROS-induced damage, anti-oxidant responses, physiological capacity and longevity. A new study examines how these traits in honey bees are affected by age and behavioral intensity (factors which can be experimentally decoupled via manipulation of colony demographics), and is the first to use such an approach to test the oxidative stress model of aging in a free-living organism.

Background

Behavioral development in adult honeybees involves a stereotypical transition from energetically-inexpensive hive work to energetically-expensive foraging behavior at approximately 3 weeks of age. Each day after this transition, a foraging bee (which weighs only 80 mg, or roughly equivalent to a breath mint) will on average fly 8 km (5 miles), contract their wing muscles approximately 4,000,000 times, and reduce approximately 60 ml of pure oxygen in its thorax (the body segment housing the flight muscles). Age and foraging behavior should have strong affects on cellular oxidative stress and antioxidant mechanisms, especially in flight muscle, as well as functional senescence. In this study the researchers used single-cohort colonies to experimentally manipulate the onset of foraging and compare markers of oxidative damage and antioxidant mechanisms among different tissues (head vs. thorax), age-matched behavioral groups (hive bees vs. foragers) and periods of the day (morning vs. afternoon), with the prediction that such markers are prevalent in high-intensity tissues, behaviors and day-time periods.

The study was conducted by Stephen P. Roberts, Michelle M. Elekonich and Jason B. Williams, all of the School of Life Sciences, University of Nevada Las Vegas. Their study was funded in part by the National Science Foundation (NSF) and the National Institutes of Health (NIH) and is entitled Oxidative stress and antioxidant mechanisms at the transition to an aerobically intensive lifestyle in honey bees. Dr. Roberts is presenting the team's preliminary findings at the 2008 American Physiological Society Intersociety Meeting The Integrative Biology of Exercise V (APS; www.the-APS.org/press).

Study Summary

Honey bees were reared in single-cohort colonies to enable sampling and comparisons of (a) same-aged bees performing different behaviors and (b) different-aged bees performing the same behaviors. Comparison groups were 8-10 day-old (precocious) foragers, 8-10 day-old (typical) hive bees, 30-32 day-old (typical) foragers and 30-32 day-old (over-aged) hive bees. Antioxidant proteins Hsp70 and catalase were measured in head and thorax tissues using western blot. Total antioxidant capacity of the tissues was measured as the ability of homogenate to inhibit the oxidation of ABTS® (2,20-azino-di-[3-ethylbenzthiazolinesulphonate]) to ABTS+® relative to trolox standards. Protein carbonylation, aconitase Vmax inhibition and mitochondrial H2O2 production were measured as markers of oxidative damage.

The Preliminary Study Results

The research team found that:

Conclusions

According to Dr. Roberts, the study's first author, "These data show that transitions to aerobically-expensive behaviors in organisms living free in nature can have important consequences affecting the pace of aging and senescence. The results support a live-fast-and-die-young view of aging, but so many questions remain about how this aging model works in natural populations, especially for species like honey bees whose social complexity rivals our own."

Science News also reported these findings:
http://www.sciencedaily.com/releases/2008/09/080925072432.htm

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New Scholarship Fund

Starting 2009-2010 the Geoscience Department will have an additional scholarship to offer its graduate students.

The Natural Science Scholarship Association (NSSA) will provide $ 1,000 per year for a graduate student majoring in geoscience, with a minimum G.P.A. of 3.0 or higher.

This is actually an "old" scholarship that has existed at UNLV for some time, with rather undefined award criteria across the sciences. In speaking with the donors, it became clear that their desire is to support geoscience students, and I will soon have documentation for Wanda's signature, re-defining the agreement as noted above.

The primary donors, Judith ('83) and Wayne Bundorf have been supporters of the School of Engineering, I wish the award fully supported a graduate student, but with effective stewardship we may be able to convince the donors to expand their support.

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Faculty Publications

“Consequences of More Extreme Precipitation Regimes for Terrestrial Ecosystems,” Alan K. Knapp, Claus Beier, David D. Briske, Aimée T. Classen, Yiqi Luo; Markus Reichstein, Melinda D. Smith, Stanley D. Smith, Philip A. Fay, Steven W. Leavitt, Rebecca Sherry, Benjamin Smith, and Ensheng Weng. Bioscience, October 2008 Vol. 58, No. 9, 811-821.

This paper is the product of an international conference in Denmark under the EPRECOT (Effects of Precipitation Change on Terrestrial Ecosystems) program, funded jointly by the European Commission and the U.S. National Science Foundation. Professor Stan Smith was an invited speaker. The paper conceptually examines, through analysis of past datasets and simulation modeling, how global ecosystems will respond if precipitation inputs become larger and more variable in the future, as has been predicted by general circulation models. The authors found that fewer, larger rainfall events will be largely beneficial to arid ecosystems and to extremely wet ecosystems, but will have a negative effect on most intermediate (moist to wet) ecosystems. The paper was authored by a consortium of scientists from the United States (Colorado State, Texas A&M, Yale, UNLV) and Europe (Denmark, Sweden, Max Planck Institute in Jena, Germany), and has therefore helped publicize UNLV's climate change research efforts to an international audience.

“A bacterial ice-binding protein from the Vista ice core,” James A. Raymond, Brent C. Christener, and Stephan C. Schuster. Extremophiles, September 2008 Vol. 12, No. 5, 713-717.

Bacterial and yeast isolates recovered from a deep Antarctic ice core were screened for proteins with ice-binding activity, an indicator of adaptation to icy environments. A bacterial strain recovered from glacial ice at a depth of 3,519 m, just above the accreted ice from Subglacial Lake Vostok, was found to produce a 54 kDa ice-binding protein (GenBank EU694412) that is similar to ice-binding proteins previously found in sea ice diatoms, a snow mold, and a sea ice bacterium. The protein has the ability to inhibit the recrystallization of ice, a phenotype that has clear advantages for survival in ice.

“Pulsed Oxidation and Biological Evolution in the Ediacaran Doushantuo Formation,” by Kathleen A. McFadden, Jing Huang, Xuelei Chu, Ganqing Jiang, Alan J. Kaufman, Chuanming Zhou, Xunlai Yuan, and Shuhai Xiao. Proceedings of the National Academy of Sciences (PNAS) 2008 105:3197-3202; doi:10.1073/pnas.0708336105.

Recent geochemical data from Oman, Newfoundland, and the western United States suggest that long-term oxidation of Ediacaran oceans resulted in progressive depletion of a large dissolved organic carbon (DOC) reservoir and potentially triggered the radiation of acanthomorphic acritarchs, algae, macroscopic Ediacara organisms, and, subsequently, motile bilaterian animals. However, the hypothesized coupling between ocean oxidation and evolution is contingent on the reliability of continuous geochemical and paleontological data in individual sections and of intercontinental correlations. Here we report high-resolution geochemical data from the fossil-rich Doushantuo Formation (635–551 Ma) in South China that confirm trends from other broadly equivalent sections and highlight key features that have not been observed in most sections or have received little attention. First, samples from the lower Doushantuo Formation are characterized by remarkably stable δ13Corg (carbon isotope composition of organic carbon) values but variable δ34SCAS (sulfur isotope composition of carbonate-associated sulfate) values, which are consistent with a large isotopically buffered DOC reservoir and relatively low sulfate concentrations. Second, there are three profound negative δ13Ccarb (carbon isotope composition of carbonate) excursions in the Ediacaran Period. The negative δ13Ccarb excursions in the middle and upper Doushantuo Formation record pulsed oxidation of the deep oceanic DOC reservoir. The oxidation events appear to be coupled with eukaryote diversity in the Doushantuo basin. Comparison with other early Ediacaran basins suggests spatial heterogeneity of eukaryote distribution and redox conditions. We hypothesize that the distribution of early Ediacaran eukaryotes likely tracked redox conditions and that only after ≈551 Ma (when Ediacaran oceans were pervasively oxidized) did evolution of oxygen-requiring taxa reach global distribution.

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Midwestern Conference on Combinatorics and Combinatorial Computing (MCCCC)

The UNLV Mathematics Department will host the 2008 Midwestern Conference on Combinatorics and Combinatorial Computing (MCCCC). This meeting originated as the Carbondale Combinatorics Conferences and the 1986-`990 gatherings were held at the Southern Illinois University, Carbondale. The conference has since evolved to a prestigious national meting in the areas of combinatorics and computing and has achieved recognition and attracted scholars and researchers of various backgrounds from different institutions. Here they coalesce their individual contributions into a collection of ideas and inspirations for the advancement of combinatorics and combinatorial computing. Papers have covered a spectrum of pure and applied combinatorics, including graph theory, design theory, enumeration, and combinatorial computing. These are general-purpose combinatorics meetings with some emphasis on computer applications which have attracted scholars from many parts of the United States, Canada, and overseas.

Invited Speakers include: Gary Chartrand, Western Michigan University; Ronal Graham, University of California, San Diego; Spyros Magliveras, Florida Atlantic University; Doug Stinson, University of Waterloo, Canada; and Catherine Yan, Texas A&M University.

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Fenton R. Kay (kayrat@lascruces.com) B.S., 1967; M.S., 1969, UNLV; Ph.D., 1974, New Mexico State University; Post-Doc, 1974-1976, University of Florida

Fenton R. Kay

How did your childhood influence your educational pursuits?

I was an avid hunter and “fisherkid” and wandered all over the Las Vegas Valley and spent summers at Lake Meade as a kid in the 1950s. At about the age of 13 I read every natural history and animal identification book I could find. I received a BB gun one Christmas when I was living in Whitney (East Las Vegas) and I took off “rabbit hunting” and wandered up onto Whitney Mesa – meanwhile my family was waiting holiday dinner and wondering where I was – I was in about the 2nd or 3rd grade. By the time I graduated from Rancho High School I decided that I wanted to be a chemist or chemical engineer. Not long into my first year of College in Cedar City. Utah (College of Southern Utah) I figured out that my math shortcomings were going to make it harder to be a chemist than I was willing to work. After my first year of college I accepted a job with EG&G as a photo lab technician and worked at the Nevada Test Site for about a year – I worked on and witnessed the last surface detonation of a nuclear bomb and watched the formation of the Sudan Crater. I moved to the San Francisco Bay Area and worked as an electronics assembler for about a year and decided that I needed to go back to school, with advice from by a friend who was a counselor at Stanford University. I returned to Las Vegas and enrolled at UNLV in Spring 1963. I bounced around various majors – political science, history, education – and then I met Mike O’Farrell, a biology student involved in research projects with Dr. Glen Bradley. Mike convinced me that biology was more than dissecting frogs and introduced me to “Brad.” We walked into Brad’s office and he had a small snake in his hand that he was trying to identify. He thought it was an immature gopher snake. I looked at it and, remembering the snake books I had read as a kid, remarked that it had elliptical pupils and I thought gopher snakes had round pupils. I was in! Brad and Jim “Deac” Deacon had a bunch of undergraduate students working with them on a variety of research projects dealing with desert ecology – I was hooked and I was accepted, and I have never looked back.

Why did you attend UNLV?

When I decided to return to school I needed to go somewhere that I could afford and that I could live. I had been raised in Las Vegas and my family lived there so I had a place to live on the cheap. I qualified for resident tuition and I could renew my National Defense Student Loan to cover tuition costs. It was a natural for me, although I was somewhat reticent because it was still thought of as “No-name U.” That was 1963 and it was still officially the Southern Regional Division of the University of Nevada – unofficially it was Nevada Southern – even more unofficially, it was “Tumbleweed Tech.” My student id number was something like 763 – UNLV started numbering the students from 1 and in alphabetical order when they set up the system. In my second semester I was the Sophomore Class Senator on the student senate.

What surprised you the most about UNLV?

The faculty was really very good and the students were real college students, even though we all necessarily lived off-campus. I learned how to do research from Dr. Wright in a Historiography class and I “discovered” biology because the biology faculty had to use undergraduate students to carry out their research projects and we got to do “real” science as undergrads. Most of the faculty members were not remote - we were a small school and everyone knew everyone else.

Do you recall any memorable faculty members, fellow students, and places on campus, events, or activities?

Dr. Wright in History, Bill Fiero of Geology, Glen Bradley and Jim Deacon in biology. Glen Bradley was one of the very best teachers I have ever had. He led us to knowledge and had a way of lecturing which was more like story-telling – he wasn’t easy, but he rewarded people who tried. Bert Babero and Chad Murvosh were really great mentors in that they adapted to the undergraduates in the research model that Glen and Jim had established and became close associates, not just professors. Years later when I worked for the Nevada Department of Wildlife in Reno I had a reason to call Bert about a collecting permit application he had submitted. He immediately remembered me and asked if I was interested in working with him on a research project – Bert gave me an authorship on a paper he published on parasites of horned lizards (I had provided him with the specimens and helped a little with the dissections to get the worms – I was the “curator” of the reptile museum at the time – an undergraduate on work-study) – and this was my very first professional publication.

How did you develop an interest in science?

I loved chemistry in high school (I had bought a chemistry kit as a 5th-grader in Los Angeles and set up a “lab” behind my granddad’s garage – I got in a lot of trouble for that because I bought the kit in violation of direct orders not to) and took an advanced chemistry class (this was way before the concept of advanced placement courses hit Las Vegas – it was an experiment by a forward-looking high school chemistry teacher) that was equivalent to freshman college chemistry. Doing lab experiments was immense fun – and I was good at lab work. Unfortunately, I was not good at math. I decided in high school that I wanted to be a chemist, later I decided that I wanted to do some kind of research and that led to my getting into biology (political science and history were interesting, but way too gray – I hadn’t yet learned how gray things get in “real” science).

How did UNLV prepare you for graduate education/career?

Because I was able to do research and start publishing as an undergraduate, the move into graduate school was a no-brainer. I hit graduate school with most of the tools I needed to be successful. I advanced to the M.S. program in biology at UNLV immediately after completing my B.S. Now to be honest, I had thought about some time off from school, but President Johnson announced that anyone that was in graduate school by July of 1967 would get a deferment (and not go to Viet Nam – I had gone for my pre-draft physical and had a temporary deferment to finish my B.S.). I was signed up for graduate school before the ink dried on my Bachelor’s degree. Besides, I had already taken a couple of grad-level courses so I was well started.

What advice would you give students who are thinking about attending UNLV?

Go for it – I have never regretted having two degrees from UNLV.

What are your proudest accomplishments?

Getting my Ph.D. – I was a first generation college graduate. My mother had started college but never finished. I was the first in my family to get any kind of college degree, let alone an advanced degree. I enjoy helping point students toward understanding science at any level. I have taught at the university level as well as at the community college level and have throughout my career kept my hand in teaching even though I have moved into the private sector and government for my living.

What are your future plans?

I am rapidly approaching the time when I can retire and finish the great American mystery novel, write my memoirs for my kids and grandkids, play around with digital photography, and take care of my yard, flower beds, and vegetable garden. And – maybe find enough money to travel some more – I’ve been to Ireland, Puerto Rico, Mexico and Belize – I’d like to go to Australia and South Africa – and back to Ireland.

Any Other Thoughts?

I have worked as a research biologist, a teacher, a computer programmer, and a data analyst. Things I studied as a student have proven to be things I have used to make a living – not just the things in which I got my degree. Throughout my career to date, having an advanced degree has always served to provide me with employment opportunities and salaries above what I might have gotten without the degree. I have almost always been able to do things that I enjoyed, even though they weren’t always biology. I suspect that had I not gone to UNLV and hooked up with Bradley’s Bums and Deacon’s Dogs, my life would have been a lot less interesting – you haven’t heard all of my stories yet.

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Summer 2008 Graduate Student Degrees

Mohammed M. Abdel-al (BIOCHE), M. S. Thesis: “ACTIVATION OF PLATELET- FACTOR ACETYLHYDROLASE BY PROINFLAMMATORY MEDIATORS,” Mentor: Dr. Ronald Gary.

Roberto Felix (CHE), M.S. Thesis: “STUDY OF THE INTERACTION BETWEEN HYDROGEN AND CARBON-BASED NANOMATERIALS,” Mentor: Dr. Clemens Heske.

Liliya Harizanova (BIOCHE), M.S. Thesis: “INTERLEUKIN-10 INHIBITS CYTOKINE-MEDIATED SYNERGISTIC RELEASE OF INTERLEUKIN-6 IN ASTROCYTOMA CELLS,” Mentor: Dr. Bryan Spangelo.

Tonia Arriola, (GEO), M.S. Thesis: “KINEMATICS AND TIMING OF OROGEN-PARALLEL FLOW, GROUSE CREEK MOUNTAINS, UTAH,” Mentor: Dr. Michael Wells.

Ales Roy (GEO), M.S. Thesis: “THE MAYAN ICE CAP: GLACIAL GEOLOGY AND PALEOCLIMATE OF THE NORTHERN GUATEMALAN HIGHLANDS,” Mentor: Dr. Matthew Lachniet.

Jun Yin (GEO), Ph.D. Dissertation: “SPATIOTEMPORAL VARIATION IN SOIL MOISTURE AND HYDRAULIC PROPERTIES AND THEIR IMPACTS ON RAINFALL-RUNOFF AND INFILTRATION PROCESSES,” Mentor: Dr. Zhongbo Yu.

Kristan Paulsen (MAT), M.S. Professional Paper: ATTITUDES OF PERSONAL ABILITIES IN LOWER LEVEL COLLEGE MATHEMATICS,” Mentor: Dr. Carryn Bellomo.

Kahadawala Cooray (MAT), Ph.D. Dissertation: “STATISTICAL MODELING OF SKEWED DATA USING NEWLY FORMED PARAMETRIC DISTRIBUTIONS,” Mentor: Dr. Malwane Ananda.

Stephanie Gayvert (SOLS), M.S. Thesis: “COLONIZATION AND INVASION OF A LAKE DRAWDOWN IN THE MOJAVE DESERT,” Mentor: Dr. Lawrence Walker.

Eun-Hae Kim (SOLS) M.S. Thesis: THE CONSERVED MECHANISM OF ICSA POLAR TARGETING AMONG PROTEOBACTERIA, CHARACTERIZATION OF THE OMPTIN FAMILY, AND THE ROLES AND REGULATION OF ICSP IN SHIGELLA FLEXNERI,” Mentor: Dr. Helen Wing.

Vanja Velickovska (SOLS), Ph.D. Dissertation: “PROTEIN DEGRADATION IN MAMMALIAN HIBERNATOR, SPERMOPHILUS LATERALIS” Mentor: Dr. Allen Gibbs.

Craig Allen-Bias (RADCHE), Ph.D. Dissertation: “ENHANCED DETECTION OF INDUCED FLUORESCENCE FROM RESIDUAL RADIOACTIVE MATERIALS,” Mentor: Dr. Kenneth Czerwinski.

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2008 ACS Western Regional Meeting in Las Vegas, NV, September 23 -27, 2008

The 2008 American Chemical Society (ACS) Western Regional Meeting took place in Las Vegas, Nevada from September 23-27, 2008 with approximately 570 attendees. Several UNLV Chemistry Department faculty and students participated in this event, joined by colleagues from across campus and throughout southern Nevada.

A number of faculty members and students organized and offered panels, discussions sections, presentations, and posters.

Presentations and abstracts:

Materials for Renewable Energy Applications
Organizer: Clemens Heske UNLV, Las Vegas
Presider: Clemens Heske University of Nevada Las Vegas, Las Vegas, NV
Session Overview: This all-day symposium focuses on material science aspects of renewable energy applications. Topics include materials for inorganic and organic solar cells, hydrogen production and storage, fuel cells, light-emitting devices, and all aspects of materials characterization. Presentations in the symposium will include invited talks as well as oral contributions. Poster contributions will be presented in a general poster session that is open for all areas of Chemistry and Biochemistry.

The Chemical and Electronic Structure of Platinum-Based Nanoparticle Catalysts for PEM Fuel Cells
Yufeng Zhang1, Lothar Weinhardt1, Timo Hofmann1, Marcus Bär1, Clemens Heske1 and Tai-Tsui Aindow2, (1)University of Nevada Las Vegas, Las Vegas, NV, (2)UTC Power, South Windsor, CT The chemical and electronic structure of platinum-based nanoparticle catalysts for PEM fuel cells has been studied by soft x-ray emission (XES) and absorption (XAS) as well as x-ray (XPS) and ultraviolet (UPS) photoelectron spectroscopy. We have focused on the investigation of the effect of different annealing temperatures and chemical treatments on the properties of Pt3Co catalyst and in particular on the question whether or not a core (Co) – shell (Pt) structure is formed.

The comparison of the Co L-edge and O K-edge XES and XAS data of the Pt3Co nanoparticles with that of reference samples reveals that the annealing process gradually transforms Co from its initial chemical state in the precursor to its metallic state. Furthermore, the Co/Pt ratio on the sample surface, calculated by using the Co and Pt core level XPS peaks, decreases with increasing annealing temperature. Nevertheless, even for the highest annealing temperature (925 ºC), Co can still be observed by the surface-sensitive XPS technique (information depth: ~ 3 nm). This would suggest that there is no “ideal” Co-Pt core-shell structure, i.e., either its shell formation is incomplete (inhomogeneous) or the shell is very thin. However, after acid washing no Co signal is observed in XPS for the Pt3Co nanoparticles. Yet, a distinct Co signal can be observed from more bulk-sensitive XES technique (information depth: ~ 65 nm). This data is in agreement with a Co-Pt core-shell structure for those nanoparticles.

Additionally, we find that the overall valence band structure of annealed Pt3Co nanoparticles is more similar to that of a Pt foil than to that of a Co foil. The resemblance of the Pt3Co valence band structure to that of Pt might be an indication that Pt3Co nanocatalysts are suitable catalysts for fuel cell systems that reduce cost by using a smaller amount of Pt.

Geometric and Electronic Structures of Ti-Al and Hydrogenated Ti-Al Nanoclusters T. J. Dhilip Kumar, P. Tarakeshwar and N. Balakrishnan, University of Nevada Las Vegas, Las Vegas, NV

The formation of small Ti or Ti-Al clusters in sodium alanates upon cycling under H2 atmosphere has been attributed to significantly improved kinetics of H2 adsorption and desorption processes. The catalytic activity of these clusters in this hydrogen storage material is not understood. Hence, we have investigated the nature of Ti-Al and corresponding hydrogenated clusters by performing unrestricted spin-polarized ab initio density functional theory calculations using VASP code. The Perdew-Wang generalized gradient approximation was used.

The geometric and electronic structures of Ti12Al and Al12Ti clusters with the lone element encapsulated in icosahedral (Ih) and cuboctahedral (Oh) cages have been studied. The binding energy of Ih cluster is found to be higher than Oh cluster. Ih cluster is found to be distorted while Oh is symmetric. Various hydrogenated clusters of Ti12Al and Al12Ti have been optimized with multicentered hydrogen bonds. Minimum energy path (MEP) for H2 adsorption and desorption are determined using the nudged elastic band method. MEPs of H2 adsorption and dissociation process on these clusters are obtained which shows that alloying Al clusters with Ti modifies the absorption energy barrier.

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Spectroscopic Investigation of Cu/Pd Bimetallic Systems for PEM Fuel Cell Catalysts Timo Hofmann1, Marcus Bär1, Yufeng Zhang1, Clemens Heske1, Dr. Xiaoping Wang2, Nancy N. Kariuki2, Suhas Niyogi2, Matt Smith2 and Deborah J. Myers2, (1)University of Nevada Las Vegas, Las Vegas, NV, (2)Argonne National Laboratory, Argonne, IL

One of the main barriers to commercialization of polymer electrolyte fuel cells systems is cost, which is largely due to the use of platinum (Pt)-containing catalysts. In this study we investigate bimetallic systems consisting of a base metal (copper) that acts as a host and a noble metal (palladium) that, as an alloy on the nanoscale, mimics the electronic properties that make Pt desirable as a catalyst. The most important property of the catalyst that determines the oxygen reduction reaction (ORR) activity is said to be the d-band center. It has been found that surface bond energies correlate with the average energy of the d-states on the surface atoms to which the adsorbate binds.

In this contribution we present a detailed investigation of the electronic structure of carbon-supported Cu/Pd nanoparticle catalysts, model bulk electrodes, and various metal reference samples. We have investigated the valence band structure of the catalysts both for occupied as well as for unoccupied states using a combination of X-ray photoelectron spectroscopy (XPS), UV photoelectron spectroscopy (UPS), and inverse photoemission spectroscopy (IPES). We have studied the approach of modifying the d-band structure of a noble metal skin on a base metal core by fabricating/characterizing bulk electrodes of the pure base metals before and after depositing thin films of the noble metal using electron-beam evaporation. Furthermore, we have investigated carbon-supported bimetallic nanoparticles, fabricated at ANL by colloidal and impregnation techniques.

In our experiments, particular focus was placed on the determination of the overall d-band structure and, in particular, the d-band center of the catalysts. We show that it is important to consider the entire d-band for describing the electronic structure of the catalyst. In our presentation, we will compare the observed electronic structure with measured ORR activities.

Medicinal Chemistry in Cancer Drug Development
Organizer: Ron Fiscus Nevada Cancer Institute, Las Vegas
Organizer: Ronald Gary University of Nevada, Las Vegas, Las Vegas, NV
Presider: Ronald R. Fiscus, Ph.D. Nevada Cancer Institute, Las Vegas, NV

Effect of Divalent Beryllium on Cellular Kinases and Cell Cycle Progression in Human Tumor Cells
Ronald K. Gary, Swapna R. Mudireddy and Priyatham Gorjala, University of Nevada, Las Vegas, Las Vegas, NV

Divalent beryllium salt at low micromolar concentration causes a series of unique physiological responses in cultured cells. However, the specific molecular targets that interact with beryllium to elicit such responses have not yet been identified. In human tumor cells, Be2+ selectively inhibited GSK3-beta, a kinase that helps to regulate proliferation and differentiation. Some investigators have suggested a role for GSK3-beta in controlling levels of p21, a potent cyclin-dependent kinase inhibitor that acts as an endogenous cell cycle regulator. Be2+-treatment induced p21 expression, as judged by RT-PCR analysis of mRNA levels, but the effect was cell type-specific. It is possible that extracellular Be2+ may not enter some kinds of cells efficiently. However, ICP-MS measurements indicated that the cell type-specific response was not due to differential uptake of the ion. The potential of beryllium to serve as a selective enzyme inhibitor is discussed in the context of a model for the coordination of beryllium and target protein side chains.

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On-Line Dechlorination-Hydrogenation of Chlorinated Paraffin Mixtures Using GC and GC/MS
Spencer M. Steinberg and David W. Emerson, Ph.D., University of Nevada, Las Vegas, Las Vegas, NV

Chlorinated paraffins are straight chain hydrocarbons that are produced as complex mixtures and are used as flame retardants and paint additives. Carbon chain length is an important parameter for assessing physical properties, use and toxicity of these materials. Conventional gas chromatography cannot be used to characterize these materials, because the resulting unresolved complex chromatogram prevents the identification and quantification of individual congeners. A previously method uses a Pd catalyst held in the GC (gas chromatograph) injector to simultaneously dechlorinate the complex mixture and separate the resulting alkanes. The catalyst was Chromasorb® red coated with PdCl2 which was reduced at elevated temperature with hydrogen. Hydrogen serves both as the reductant and as the carrier gas in this analysis. Attempts to reproduce this method resulted in erratic performance. However, when catalyst preparation procedure was modified by reducing the Pd(Cl)2, deposited on the Chromasorb, with sodium borohydride the method performance drastically improved and resulted in clear quantitative dechlorination of paraffin mixtures as well complete to partial reduction of other halogenated species. To adapt this approach to gas chromatography-mass spectrometry (GC/MS) an SIS Pyro-Injector™ that was interfaced to a Varian Saturn III GC/MS. The pyro-injector's quartz liner contained the catalyst material and catalyst temperature was adjustable independently of the GC injector temperature. The GC injector was set to 25:1 to 50:1 split ratio and helium was used as the carrier gas. The injector split prevented most of the hydrogen from reaching the mass spectrometer and the small fraction of hydrogen in the carrier did not impact the mass spectrometer performance. Using this set up quantitative dechlorination was achieved, and product identities were confirmed by GC retention time as well as mass spectrometry. Dehalogenation of other compounds was also studied with this system for potential application to other complex halogenated mixtures.

Vanadium in Southern Nevada Water: Speciation of V(IV) and V(V) by IC-ICPMS
Sujanie V. Gamage, James V. Cizdziel, Kazumasa Lindley, Vernon F. Hodge and Klaus J. Stetzenbach, University of Nevada Las Vegas, Las Vegas, NV

Vanadium is a naturally occurring trace element found in air, soil, water and biota. It can exist in several oxidation states. The most common forms in natural waters are V(IV) and V(V). A rapid and sensitive method was developed to identify trace amounts of V(IV) and V(V) in Southern Nevada groundwater and spring water using an ion chromatograph to separate the species and an inductively coupled plasma mass spectrometer to detect the element (IC-ICPMS). An ion exchange column was used with 1.5% HNO3 as the eluent, at a flow rate of 1.50 mL/min. Water samples were injected directly to the column without any preconcentration or dilution. The vanadate ion V(V) was eluted first followed by the vanadyl ion V(IV), giving two distinct peaks in less than 6 min. To avoid polyatomic interferences formed in the plasma, such as 35Cl16O+ which is isobaric with 51V, a dynamic reaction cell was used with ammonia gas at a rate of 0.5 mL/min. The limits of detections are 0.05 µg/L for V(V) and 0.10 µg/L for V(IV). The results indicate that more than 90% of the vanadium in the groundwater and spring water examined in this study exists in the vanadate form. The concentration of V(V) ranges from 6.70 µg/L to 79.13 µg/L and V(IV) from 0.37 µg/L to 0.97 µg/L in the groundwater and, from 2.33 µg/L to 5.81 µg/L and 0.29 µg/L to 0.40 µg/L in the spring water, for V(V) and V(IV) respectively. The relative concentrations of vanadium's oxidation states may help gauge the redox conditions of groundwater near Yucca Mountain.

Emerging Contaminants: Perchlorates, Pharmaceutics, and Personal Care Products
Organizer: Jacimaria Batista UNLV, Las Vegas
Organizer: Lantis I. Osemwengie USEPA, Las Vegas, Las Vegas, NV
Presider: Jacimaria R. Batista University of Nevada Las Vegas, Las Vegas, NV
Presider: Lantis I. Osemwengie USEPA, Las Vegas, Las Vegas, NV

Nanotechnology Research, Applications and Exposure Issues.
Organizer: Jeanette M. Van Emon, Ph.D. US Environmental Protection Agency, Las Vegas, NV and David W. Emerson, Ph.D. University of Nevada, Las Vegas, Las Vegas, NV
Presider: Jeanette M. Van Emon, Ph.D. US Environmental Protection Agency, Las Vegas, NV

New Developments in Biofuels Research
Organizer: Oliver Hemmers UNLV, Las Vegas
Presider: O. Hemmers University of Nevada, Las Vegas, Las Vegas, NV

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Study on the Energy Value of Production from Microwave Assisted Pyrolysis of Sewage Sludge

Xuxin Zhao1, Lin Fang1, Yu Tian, N/A2 and Marcos A. Cheney, Ph.D.3, (1)Shenzhen University, Shenzhen, Guandong 518060, China, (2)Harbin Institute of Technology, Harbin Heilongjiang 150090, China, (3)University of Nevada Las Vegas, Las Vegas, NV

Abstract: It is estimated that by the year 2010 in China, the amount of sewage sludge produced will reach 20 million tons per year and the cost for sewage sludge treatment will increase to 25 to 45% in the sewage treatment plant. For this reason we must invest efforts on developing new methods for the production of energy from sewage sludge and solid waste along with sustainable utilization. One method that is attracting considerable interest is microwave-assisted pyrolysis (MAP) of sewage sludge to produce oil and gas. In this paper, we have applied MAP to produce oil and gas from sewage sludge, and compared with those from conventional pyrolysis using an electrical furnace. The produced oil and gas were analyzed by GC-MS, GC, and oxygen bomb calorimetry. The results show that the sewage sludge can be efficiently pyrolyzed in the microwave with SiC and carbonaceous residues as microwave receptors respectively. When SiC was used microwave receptor, the efficiency of MAP of sewage sludge to produce oil and gas was higher than when carbonaceous residues were used. The percentage of PHAs in oil productions of MAP were 5.37% and 3.29% with SiC and carbonaceous residues as microwave receptors respectively, with is lower than the oil from conventional pyrolysis using an electrical furnace. The energy value of oils from different MAP of sewage sludge can reach to over 35.6MJ/kg. The mass of the produced gasses from MAP of sewage sludge was over 76% of the total mass of pyrolysis of organic matter, while the volume of H2 and CO was over 54% of the total volume of gasses, and the energy value can reach to 9420 kJ/m3.

The Chemistry of Biofuels, An Overview
David W. Emerson, Ph.D., University of Nevada, Las Vegas, Las Vegas, NV

Much of the current national debate regarding our need for energy independence is focused on wind, geothermal, and solar sources. In this talk, we point out that micro-algae generated biodiesel fuel could play a very significant role in achieving energy independence in a much shorter period of time than is generally recognized. Furthermore, it could provide a natural bridge between current fossil fuel technologies and future renewable technologies. We discuss the chemistry and chemical engineering needed to make this happen.

Synthesis of Ionic Conducting Polymers for Fuel Cell Applications and Biodiesel Productions

Tae Soo Jo and Chulsung Bae, University of Nevada, Las Vegas, Las Vegas, NV

Our daily life heavily depends on fossil fuels to produce energy, however, they cause severe environmental problems and reserves are drying up rapidly. Clean, efficient, and reliable energy production is one of the most important issues in the 21st century. Among many alternative energy generators, fuel cells or biodiesels offer the most promising energy solution for powering remote area and automobiles. The proton exchange membrane fuel cells have been widely investigated for applications in automotive, stationary, and portable electronics for the upcoming future due to its high energy conversion efficiency and environmentally friendly energy generation. Another technology, biodiesel has emerged as a promising alternative fuel because it is biodegradable, burns cleaner, emits significantly less hydrocarbons than petroleum-based fuels.

Wholly aromatic polyamides (e.g., Kevlar and Nomex) are one of the best-known engineering plastics for possessing excellent thermal and mechanical stabilities. Thus, similar to other rigid aromatic polymers, sulfonated derivatives of aromatic polyamide can be an attractive proton transporting material that keeps many good properties of polyamides. Furthermore, its sodium salt form of membranes can be used to generate sodium methoxide, which is a critical reagent for the current biodiesel production process. Although this potential use of sulfonated polyamides as PEM or biodiesel has been suggested in literature, synthesis of sulfonated polyamides has been not fully explored. To create ionic-conducting membranes for fuel cells or biodeisel, a new class of sulfonated poly(ether amide)s is prepared via polycondensation reactions of four different diamines, two fluorinated dicarboxylic acids and sulfonated terephthalic acid. Ion exchange capacity (IEC) values of the sulfonated poly(ether amide)s were in good agreement with the calculated values. Some sulfonated poly(ether amide)s showed higher proton conductivity (0.1 S/cm at 80 oC) than that of Nafion 117, currently the state-of-the-art fuel cell membrane in the market.

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High Caloric Fuel Produced from Microwave Assisted Pyrolysis of Sewage Sludge: Process Optimization
Lin Fang, Ph.D.1, Xuxin Xuxin1, Yu Tian2 and Marcos A. Cheney, Ph.D.3, (1)Shenzhen University, Shenzhen, Guandong 518060, P.R. China, Shenzhen, Guandong 518060,, China, (2)Harbin Institute of Technology, Harbin Heilongjiang 150090, China, (3)University of Nevada Las Vegas, Las Vegas, NV

Environmental pollution from the increasing output and disposal of sewage sludge (SS) is a matter of great concern. And the dried SS has more than 70% organic substance and 4000 Kcal/Kg heating values. So the utilization of sewage sludge is proved to be an important environmental problem. We have developed a new method to produce high caloric fuel from sewage sludge using microwave assisted pyrolysis. The objective of this work was to optimize the condition of this method for obtaining fuel with high caloric. The temperature, using this method, of SS was monitored by means of an infrared optical pyrometer. The heating temperature for SS with different water content in the field of microwave was 200 oC only. When the SS was mixed with microwave receptors (SiC, carbonaceous residue and Fe2O3) respectively, the mixture of SS and microwave receptor can be rapidly heated to 800 oC and efficiently pyrolyzed. High caloric fuel can be produced from microwave assisted pyrolysis of SS. Further optimization of the process to produce high caloric fuel was done using the orthogonal design method consisting of 3 factors (mass of sludge, mass of microwave receptor, power of microwave) and 2 targets (temperature up to 800 oC and minimum consumed energy). The best conditions were determined as follows respectively: (a) mixture of 10g SiC and 40g wet SS followed by pyrolysis in the microwave of 1200w, (b) mixture of 8g Fe2O3 and 25g wet SS followed by pyrolysis in the microwave of 1400w, and (c) mixture of 10g the carbonaceous residue and 35g wet SS followed by pyrolyzis in the microwave of 1400w. All these processes could reach 800 oC rapidly, realize efficient pyrolysis, and generate gas with high caloric content and low sulfide consistence.

Radiochemistry in the Advanced Nuclear Fuel Cycle

Organizer: Ken R. Czerwinski University of Nevada, Las Vegas, Las Vegas, NV
Presider: Kenneth R. Czerwinski University of Nevada - Las Vegas, Las Vegas, NV

Technetium and Uranium Separation and Conversion for the UREX Process Gordon Jarvinen1, Doris K. Ford1, Kristy M. Long1, Kenneth R. Czerwinski2, Frederic Poineau2 and Edward Mausolf2, (1)Los Alamos National Laboratory, Los Alamos, NM, (2)University of Nevada, Las Vegas, Las Vegas, NV

The Uranium Extraction (UREX) process is the first solvent extraction operation in a group of separation processes generically called UREX+ that is part of the Global Nuclear Energy Partnership (GNEP) Program of the U.S. Department of Energy. The UREX+ processes have been developed as a baseline set of separation operations to partition the components of spent light-water reactor fuel to enable recycle of the actinides and more efficient disposition of the fission products. The UREX process selectively extracts uranyl nitrate and pertechnetate from the actinide and fission product mixture resulting from dissolving spent fuel in nitric acid into a solution of tributylphosphate in a hydrocarbon diluent and back extracts these species into dilute nitric acid. Technetium is a fission product of particular concern to the environment because of its long half-life (214,000 years) and high solubility and mobility in groundwater as pertechnetate under oxidizing conditions. An efficient process for separation and concentration of the technetium from this process stream is under development. Using an anion exchange resin to remove the pertechnetate from the uranyl nitrate solution provides a viable route to separate the technetium from uranium. The uranium is precipitated from the acid solution after ion exchange with ammonium hydroxide and calcined to U3O8. The pertechnetate is eluted from the anion exchange resin with ammonium hydroxide, the solution concentrated by evaporation, and the technetium incorporated into a potential waste form. The waste forms that are under investigation include technetium alloys and ceramic oxides.

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Synthesis of New Macrocyclic Compounds for the Selective Extraction of Technetium-99 Patricia Paviet-Hartmann, UNLV, Las Vegas, NV, Jared Horkley, ISU, Idaho Falls, ID, Eric Brown, BSU, Boise, ID and Joshua J. Pak, Idaho State University, Pocatello, ID

The long half-life of technetium-99 and its ability to form an anionic species makes it a major concern when considering long-term disposal of high-level radioactive waste. Furthermore, as its most stable species in the environment, the pertechnetate ion, TcO4- is highly mobile and is considered as a long-term hazard in nuclear waste disposal. Because of the small activities of technetium-99 relative to other fission products cesium-137 or strontium-90, and its long half-life time (t1/2 = 2.1 E5 yrs), technetium-99 is one of the key isotopes that should always be analyzed in the radioactive liquid waste streams from the reprocessing industry where the largest concentrations are to be expected. However, since this radionuclide is a pure beta-emitter, tedious and time-consuming chemical separations are usually performed prior to any measurement in such complex media. There is a need for the development of new extractant systems, such as systems based on crown ethers that may serve to selectively extract and separate this long lived radionuclide from different streams for potential industrial application. In this paper, we are reporting the design and synthesis of new macrocyclic compounds to selectively extract technetium from complex mixtures. These macromolecules can be functionalized with oxygen, sulfur, and nitrogen donating functional groups with various cavity sizes and/or bonding modes. Synthesis of these macrocyclic compounds will be presented as well as preliminary tests performed for the selective extraction of pertechnetate.

Solubility and Electrochemistry of Uranyl Carbonate in a Room Temperature Ionic Liquid System
Wendy J. Pemberton, UNLV, Las Vegas, NV, Kenneth R. Czerwinski, University of Nevada, Las Vegas, Las Vegas, NV and David Hatchett, UNLV, Las Vegas

During recent years, room temperature ionic liquids (RTILs) have been examined in metal extraction systems for radionuclide separations. An additional potential use is to exploit the electrochemical possibilities provided by the RTIL system. When performing electrochemistry in ionic liquid, there is an extremely large potential window possible that is upwards of 6 volts. Free from the limitations of interferences from the aqueous based system, this large electrochemical window can be used to create a tunable actinide separation scheme in RTIL solutions.

Studies examining the addition of uranyl carbonate to an RTIL system composed of the N-trimethyl-N-butyl ammonium cation and the bis(trifluoromethanesulfonyl)imide anion will be presented. The solubility of the uranyl species will be discussed along with speciation details. Liquid scintillation counting of a system containing 233U will be examined. IR and UV-Visible spectra will be shown. Cyclic, linear sweep, and square wave voltammetry will be reviewed. Finally, uranyl deposition data will be explored.

Visible Absorbance Peak Ratios – a New Method for Determining the Concentration of Nitrate and Uranium in Reprocessing Streams
Nicholas A. Smith, Gary S. Cerefice and Ken R. Czerwinski, University of Nevada, Las Vegas, Las Vegas, NV

Ultraviolet/Visible spectroscopy shows significant promise for monitoring uranium concentrations in nuclear fuel reprocessing streams. The measurement of uranium absorbance is dependant on the speciation of the uranyl ion which is influenced by the nitrate and acid concentrations in the stream. Current spectrophotometric methods rely on single wavelength measurements and fixed calibration curves to measure uranium absorbance and insert a systemic bias into the measurement due to the changing speciation. To reduce this bias, a method has been developed to determine the uranium and nitrate concentrations simultaneously. The method uses a ratio of absorbance peaks to predict the nitrate concentration of the system. This allows for a dynamic, offline calibration curve to be used when measuring uranium concentrations in a system where the speciation is changing. This approach reduces the overall measurement uncertainty and effectively removes the systemic bias from the uranium measurement.

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Monitoring of Spent Nuclear Fuel Reprocessing Studies Via UV-Visible Spectroscopy
Jamie L. Warburton and Ken R. Czerwinski, University of Nevada, Las Vegas, Las Vegas, NV

UV-visible spectroscopy was applied in a process monitoring setting as to provide a method for confirming and tracking process chemistry, specifically as applied to the separation and treatment of spent nuclear fuel. A compact, portable spectrometer and light source were connected to a fiber optic dip probe for close to real-time monitoring when inserted into process streams. The operation of the fiber optic system was first verified by comparing static sample measurements with those from a robust spectrophotometer in both single and double beam configurations. In these comparisons, specifically of the 414 nm absorption peak in a 0.113 M uranyl solution, the fiber optic spectra yielded a maximum absorption of 0.9990 as compared with the standard UV-Visible measurement of 1.0505, a 4.9% deviation relative to the latter value. While no peak shifts were present, the fiber optic system displayed significant increase in noise, so much as to wash out any spectra, at wavelengths below 360 nm and above 940 nm when compared with the standard cuvette-based UV-Visible spectrometer. As these wavelengths are outside the region of interest, the noise increase had no detrimental effect on the analysis. Preliminary results in flowing samples suggest no change in spectral results across a range of process flow rates and conservative uranium detection limits of 0.0113 up to 0.5660 M with a resolution of greater than 0.003 M. Current research focuses on quantifying and optimizing the precision of the fiber optic system across all pertinent uranium concentrations, up to 1 M uranyl for maximum spectral detail. The results will contribute to process monitoring and proliferation resistance in reprocessing.

Radiochemistry in the Advanced Nuclear Fuel Cycle
Organizer: Ken R. Czerwinski University of Nevada, Las Vegas, Las Vegas, NV
Presider: Kenneth R. Czerwinski University of Nevada - Las Vegas, Las Vegas, NV

Uranium Concentrations in Bottled Water and in Selected Municipal Water Supplies
Jessie Cisneros, Rajah Montgomery, Zaya Karharkuu, Dennis Farmer, Shingo Moriuchi and Mark Dorian, University of Nevada of Las Vegas, Las Vegas, NV

Bottled water these days is a necessity. Many families have switched from tap water to bottled varieties. There are two types of bottled water; natural and spring water with flavors added or carbonated. However, these waters can pick up minerals such as uranium from the rock (usually granite) they pass through which is toxic to the kidneys. In this study, we estimated the concentration of Uranium in 6 different types of bottled waters (all from USA): Volvic (V), Fiji (F), Trinity (T), Hawaii (H), Niagra (N), and Rim Rock (RR), 3 municipal waters from Carlsbad, NM (CNM); El Paso, TX (EPT) and Las Vegas, Nevada (LV) and 3 local environmental samples (collected from Flamingo Wash (FW) 1, 2, 3 at different flow periods). The concentrations of Uranium 238/234 in the six bottled waters tested were as follow: 0.1/0.12 (V), 0.02/0.03 (F), ND/ND (T), ND/ND (H), 0.01/0.02 (N) and 0.3/0.8 (RR) pCi/L. The concentration of Uranium 238/234 in the 3-municipal waters tested was 0.3/0.7 (CNM), 1.2/3.0 (EPT) and 1.5/2.8 (LV) (average of three analysis) pCi/L. The concentration of Uranium, 238/234 in the 3- Flamingo Wash Areas 1, 2 and 3 waters tested was 4.0/11.0 (FW1), 0.9/2.5 (FW2) and 1.9/4.8 (FW3), (average of three analysis) pCi/L. The bottled waters were weakly radioactive, but the radioactivity levels are well below what would be considered a health risk. All the waters met the WHO guideline levels for adults, which is 15 µg of Uranium per Litre. However, some samples exceeded the recommended limits of 3.2 µg/L for babies. The concern, then, is the damage this level of Uranium can cause to the kidneys of babies.

University Radiochemistry Laboratory Setup for Fuel Cycle Research
Tom ODou, University of Nevada, Las Vegas, Las Vegas, NV

Text Not Available.

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Rapid Analytical Techniques for Actinide Monitoring in the Nuclear Fuel Cycle
Julie M. Gostic, Richard C. Gostic, Julie A. Bertoia and Kenneth R. Czerwinski, University of Nevada - Las Vegas, Las Vegas, NV

This research examines the benefits of coupling laser ablation inductively coupled mass spectrometry (LA-ICPMS) and alpha spectrometry for resolving plutonium isotopic ratios. Mixed actinide samples are isolated from matrix constituents and sequentially separated using vacuum-assisted extraction chromatography. The collected fractions are prepared for counting using a cerium fluoride co-precipitation technique. The filtered samples are initially evaluated by alpha decay measurements and then ablated for mass-to-charge ratios. Preliminary results with tracer-grade solutions indicate that the analytical method successfully isolates plutonium from uranium and americium nitrato-based species and identifies plutonium isotopics from the co-precipitated samples. Mass-based analysis provides the 240 and 241 to 239 ratio, which cannot be determined/resolved with alpha measurements. Decay analysis provides the 238:239 ratio, which is below the limit of detection of the mass spectrometer. Additionally, the cerium carrier concentration is used as a homogeneity determinant for ablation analysis.

Computational studies on fuels and waste forms
Philippe F. Weck, Ph.D., University of Nevada, Las Vegas, Las Vegas, NV Text Not Available.

Liq. Ammonia as a solvent medium and reactant provides new potential pathways towards actinide nitride synthesis. Despite this, the examination of Actinides with liq. ammonia has shown a dearth of investigation in recent decades. Actinide chemistry with liq. Ammonia is best known with thorium, but the higher actinides, including uranium, are far less investigated.

The use of liq. ammonia, as well as with simple amides, is investigated for use in making uranium nitride and uranium nitride precursor compounds. Both U(III) and U(IV) starting materials were investigated, and amide materials, which can serve as synthetic intermediates, have been studied.

Subsequent heating to achieve conversion to imide/nitride is also examined for the uranium amide systems. Modeling of ammonia and amide interactions with uranium cations is also investigated.

The direct metathesis of uranium halides and trilithium nitride to produce uranium nitride is also discussed, including pathways towards optimization. Modeling of this metathesis was also investigated.

A Novel Route to Synthesize (U, Th)O2 Solid Solutions
G. W. Chinthaka Silva, Kenneth R. Czerwinski and Gary Cerefice, University of Nevada, Las Vegas, Las Vegas, NV

Oxide solid solutions can be synthesized by solid-state process, wet method, and sol-gel method. In the first two methods, the separate oxides have to be heated at elevated temperatures such 1600-1700 0C for a couple of hours. Sometimes these two methods require heating up to 48 hours and further heating depending on the oxide to be obtained as a solid solution. The sol-gel method requires substantial effort and time to synthesize a single phase oxide solid solution although the temperature necessary is lower than the two methods mentioned earlier. Due to these drawbacks, it is beneficiary to have a simple and faster method to fabricate oxide solid solutions. Here we are presenting a two-step novel low-temperature synthesis route to synthesize uranium-thorium-oxide solid solutions. In this method, separate oxides are mixed with NH4HF2 and heated in air or argon atmosphere to obtain the (U, Th)O2 solid solution.

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Plutonium Containing Inert Matrix Fuel: Synthesis and Characterization
Kiel S. Holliday and Ken R. Czerwinski, University of Nevada, Las Vegas, Las Vegas, NV

There has been a recent resurgence of interest in the different oxide fuel types as potential advanced fuel for nuclear energy systems, often highlighting the role of transuranic elements as the fissile component. Inert fuel matrices have the advantage of burning transuranic elements from the fuel cycle without the additional production of plutonium. The future of this research highlights the need for experimental work with actual transuranics, opposed to homologs in order to understand the chemical properties of the fissile material. This study uses plutonium as the fissile material in an inert matrix of zirconia and magnesia with erbia as a burnable poison. The zirconia phase adds strength and durability and incorporates the fissile material and burnable poison into a solid solution. The magnesia phase remains pure and improves the thermal and dissolution properties of the fuel. Finding a balance between the two phases and their properties will be the key factor in the fuels performance. The precipitation method was chosen to synthesize the material so that a solid solution can be obtained in the zirconia at reasonable sintering temperatures and times. This solid solution has yet to be achieved by the conventional mixing and sintering of dry powders, which result in small inclusions of a plutonium oxide phase. This study examines speciation, phase composition, phase mixing, and microstructure of the plutonium, erbium, and inert matrix using x-ray and electron interactions. This will aid in future dissolution studies aimed at understanding the chemical behavior of the material in reactor, repository, and reprocessing conditions. These dissolution studies will provide kinetic and thermodynamic data necessary for modeling.

Analysis of Iodide and Iodate in Lake Mead, Nevada and Las Vegas Tap Water Using a Head-Space Derivatization Gas Chromatography Mass Spectrometry
James W. Dorman and Spencer M. Steinberg, University of Nevada, Las Vegas, Las Vegas, NV

Iodine is a biophilic trace element that is found in multiple oxidation states in soil, rock, natural waters, and living organisms. Total inorganic iodine (TII) occurs mainly as iodate(IO3-) and iodide (I-), although other species such as molecular iodine (I2)and hypoiodate (HIO and IO-) may occur at very low abundance or as intermediates in the biological, non-biological and photochemical transformation of iodine. Total inorganic iodine TII (I- and IO3-) can be measured in environmental samples using a variety of spectrophotometric, liquid chromatographic and electrochemical methods. In addition, several gas chromatographic methods have also been reported that involve converting TII to a volatile iodine species that can be separated from interfering substances by gas chromatography. We report here a derivatization head-space method, modified from a published procedure, for the analysis of inorganic iodine in water. An aqueous iodide sample is reacted with dimethyl sulfate in a partially filled septum sealed reaction vessel to yield methyl iodide. Head-space gases from the sealed vessel are analyzed directly for methyl iodide by GC/MS. Iodate is measured by difference after reducing TII to iodide. Samples from Lake Mead, the Las Vegas Wash and from Las Vegas tap water were examined. Lake Mead and the Las Vegas Wash contained a mixture of both iodide and iodate. The average concentration of TII for Lake Mead was ~ 90nM with a ratio iodide to iodate of ~1. The TII concentration (~160nM) and the ratio of iodide to iodate was the higher for the Las Vegas Wash (~2). The TII concentration for tap water was close to that of the Lake Mead (~90nM) however, tap water contained no detectable iodide as a result of chlorine treatment which converts all of the iodide to iodate.

Medicinal Chemistry in Cancer Drug Development
Organizer: Ron Fiscus Nevada Cancer Institute, Las Vegas
Organizer: Ronald Gary University of Nevada, Las Vegas, Las Vegas, NV Presider: Ronald R. Fiscus, Ph.D. Nevada Cancer Institute, Las Vegas, NV

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Boron Intakes in Humans and Potential Associations with Cancer Susan L. Meacham, Ph.D., R.D.1, James V. Cizdziel, Ph.D.2, Allison C. A. Wallace, M.S., M.N.S.1, Memet Korkmaz, Ph.D.3, Ugur Sayli, M.D.4, Stephen W. Carper, Ph.D.1, S. Bakirdere5 and O. Y. Ataman5, (1)University of Nevada, Las Vegas, Las Vegas, NV, (2)University of Mississippi, University, MS, (3)Celal Bayar University, Manisa, Turkey, (4)Ankara Clinic Medical Center, Umitkoy, Ankara, Turkey, (5)Middle East Technical University, Ankara, Turkey

Boron (B) may be an important factor in human metabolism as an essential nutrient and, at pharmacological levels, a potential therapeutic agent for some cancers. Current estimates of normal B intakes in the US are 1-3 mg/d with a tolerable upper limit established at 20 mg/d (Institute of Medicine, 2001). Mean intakes of B have been reported to be as high as 8.41 mg/d in Turkish populations living near natural B deposits. Anticarcinogenic associations for cervical cancer have been reported in B-rich regions compared to B-poor (1.26 mg/d) regions (p<0.0001) (Korkmaz et al., 2007). In Texas ground water B was inversely correlated with prostate cancer with a 19 fold increase in B associated with a 37% reduction cancer incidence (Barranco et al., 2007). Additionally, in vitro cancer cell lines treated with boric acid (1 mM) responded with a reduction in cell growth (Wallace et al, unpublished; Meacham et al., 2008, 2007, 2006, 2005; Carper et al., 2008, 2007, 2006, 2005). An epidemiological study in Washington was not able to confirm correlations for geographic B concentrations and beneficial effects in humans (Gonzalez et al., 2007). A recent review indicated 170 items are currently marketed in the US and labeled containing B (0.07-1000 mcg/unit). Our analyses of products not labeled as containing B detected B (i.e., 137 and 152 mcg/g) using high resolution ICP-MS. NHANES III reported dietary supplement B intakes at 135 mcg/d (1994). Our previous reports confirm subjects consuming as many as 29 supplements/d adding potentially 3.9 mg B over normal intakes. With B cellular membrane transporters identified and potential mechanisms of action emerging the importance of knowing B intakes will be necessary translational research. Inconsistent and limited observations currently available warrant further investigation of B and potential healthful benefits in human subpopulations, particularly in B-rich Southern Nevada and California.

Polymer Architecture
Organizer: Pradip Bhowmik University of Nevada, Las Vegas
Presider: Pradip K. Bhowmik University of Nevada Las Vegas, Las Vegas, NV

This session is focused on various synthetic methods for multitude of polymer architectures and their structure-property-application relationships. Polymers of different architectures are an integral part of developing many functional materials. Novel methods of polymer synthesis and their characterizations by using various experimental techniques will be of interest to chemists, physicists and engineers alike.

Synthesis and Self-Assembly of T-Shaped Bisphenazines with Tunable Electronic Properties
Kyoungmi Jang and Dong-Chan Lee, University of Nevada Las Vegas, Las Vegas, NV

Self-assembly of organic semiconductors has been particularly useful in preparing one-dimensional (1D) nanostructures through various secondary interactions. Recently, these 1D nanostructures such as nanofibers and nanowires driven by intermolecular ?-? interactions of small conjugated building blocks have drawn much attention for the nanodevice fabrication due to their high charge carrier mobility resulting from intermolecular ?-orbital overlap.

In spite of the advancement in materials design, most organic semiconductors have electron-donating (p-type) characteristics. Electron-acceptors (n-type) are equally important for their application such as bipolar transistor, donor/acceptor organic solar cells, complementary circuits, etc. Consequently, developing useful n-type semiconductors is of critical importance.

A primary objective in our molecular design is to create new n-type organic semiconductors while maintaining the desired 1D self-assembling properties. To that end, novel n-type semiconductors based on T-shaped asymmetric bisphenazine containing three different peripheral substituents such as methoxy, hydrogen, and cyano groups were synthesized to investigate tunability of electronic and self-assembling property of this system depending on the substituents. These substituents gradually reduce LUMO levels, corresponding with the order of strength of electron-withdrawing properties of the substituents. Additionally, they showed 1D assembling property with a dramatic difference in morphology depending on the substituents; no assembly for methoxy, rigid microstrands for hydrogen, and flexible nanofibers for cyano substitution. Detailed instrumental analyses including SEM, DSC, and XRD are presented to imply molecular packing arrangement.

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Chemical Modification of a Crystalline Isotactic Poly(butene) Via Combination of Activation of Inert C-H Bonds and Nitrooxide Mediating Radical Polymerization
Tae Soo Jo1, Meilong Yang2 and Chulsung Bae1, (1)University of Nevada, Las Vegas, Las Vegas, NV, (2)Stanford University, Stanford, CA

Polyolefins constitute the largest volume of polymer production in the world because of their excellent mechanical properties, low production cost and good process ability. Although produced in large quantities, because of their low surface energy polyolefins have found limited applications where compatibilization with other materials, such as metals and fillers, is required. The introduction of specific functionality into polyolefins can lead to a new type of polymeric materials which can overcome the conventional problem of polyolefins. Thus, incorporation of polar groups into nonpolar polyolefins has been an active research area of both academia and industry.

We herein report that the preparation of hydroxy-functionalized isotactic poly(butene) via transition metal-catalyzed regioselective C-H borylation at the side chain of the polymer and subsequent oxidation of the boronic ester functionality. Conversion of the hydroxyl group in the polymer chain to alkoxyamines afforded a side chain-functionalized macroinitiator. Two different vinyl monomers, styrene and p-dipropylaminostyrene, were grafted into the polymer side chain via nitro oxide mediated controlled radical polymerization. The concentrations of styrene and p-dipropylaminostyrene in the grafted chain were controlled up to 40 mol% and 10 mol%, respectively. Nitration followed by reduction of styrene-grafted poly(butene) produced the corresponding aniline-grafted polymer. By using these post-modification methods, amine functionalities were introduced into the side chains of a commercial polyolefin, allowing the synthesis of a polar-block-grafted polyolefin.

Synthesis, Characterization and Properties of Phenylphosphine Oxide and Phenylpyridinium Moieties-Based Ionic Polymers as Potential High Temperature, Photoactive and Electroactive Semiconducting Materials
Maksudul M. Alam1, Wenjie Xie1, Haesook Han2, Bidyut Biswas2, Pradip K. Bhowmik2 and Kisholoy Goswami1, (1)InnoSense LLC, Torrance, CA, (2)University of Nevada Las Vegas, Las Vegas, NV

Photoactive, electroactive and robust high temperature ionic polymers have special niche applications in the areas of electronics, optoelectronics, photonics, chemical- and bio- sensors, fire and corrosion resistant coatings and structural components for automobiles, aircraft, engines, etc. We present design, synthesis and characterization of robust, high temperature resistant, photoactive and electroactive ionic polymers incorporating phenylphosphine oxide and phenylpyridinium moieties in the polymer backbone by utilizing ring-transmutation polymerization reaction of bis(pyrylium salt)s with phosphine oxide containing aromatic diamines. High yield and purity of the ionic polymers indicate the versatility of our synthetic approach. Thermogravimetric analyses show high thermal stability, glass transition and decomposition temperatures of these ionic polymers. Incorporation of phenylphosphine oxide moiety in the backbone provides high thermo-oxidative stability, high glass transition temperature, and fire retardant behavior. The use of organic counterions allows these ionic polymers to be easily processed from common organic solvents. Properties of these ionic polymers can be manipulated and/or fine-tuned by exchanging one organic counterion with another without the use of a new synthetic method. These ionic polymers also exhibit interesting optical, photoluminescence and electrochemical properties that are of interest in electronic and optoelectronic device applications.

Poly(pyridinium salt)S Containing Oxyethylene Units in the Main Chain Exhibiting Thermotropic Liquid-Crystalline and Photoluminescence Properties
Hari D. Mandal1, Pradip K. Bhowmik2, Haesook Han2, Alexi K. Nedeltchev2, Jose A. Jimenz-Hernandez1 and Patrick M. McGannon1, (1)Texas A & M International University, Laredo, TX, (2)University of Nevada Las Vegas, Las Vegas, NV

Oxyethylene units are usually incorporated either in the main chain or in the side chain to impart the solubility of numerous polymers in common organic solvents. Additionally, they also impart polymers with relatively low melting transitions because of their increased flexibility. These flexible units have been incorporated into many classes of polymers. To mention a few of them are polyamides, polyesters, polyimides, and poly(ester-imides). Several poly(pyridinium salt)s with oxyethylene units in the main chain were prepared by either the ring-transmutation polymerization of phenylated bis(pyrylium tosylate) with 1,2-bis(4-aminophenoxy)ethane or bis(2-(2-(4-aminophenoxy)ethoxy)ethyl ether in dimethyl sulfoxide or the metathesis reaction of the corresponding tosylate polymers with lithium or sodium salts of various organic counterions in appropriate organic solvents. The organic counterions incorporated into this series of poly(pyridinium salt)s by exchange reactions were triflimide, bis(2-ethylhexyl)sulfosuccinate) and dodecylbenzenesulfonate. They were characterized for their thermotropic liquid-crystalline properties and light-emitting properties in various nonpolar and polar solvents, with various experimental techniques. Although they occasionally exhibited vibrational fine structures in their excitation spectra, but they exhibited λem peaks without the vibrational fine structures. These λem peaks were dependent on the nature of solvents as well as counterions. In several cases, it was possible to record λem their emission spectra in less polar solvents such as chloroform, tetrahydrofuran and acetone because of the combination of flexible oxyethylene units and specific organic counterions present in these polymers.

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Anthropogenic Pollutants in Desert Varnish near a Coal-Fired Power Plant
Piotr Nowinski1, Vernon F. Hodge2, James V. Cizdziel3, Kazumasa Lindley2 and Klaus J. Stetzenbach2, (1)Clark County Department of Air Quality and Environmental Managment, Las Vegas, NV, (2)University of Nevada Las Vegas, Las Vegas, NV, (3)University of Mississippi, Las Vegas, MS

Rock varnish, often called desert varnish, is a manganese-rich coating that accumulates on exposed rock surfaces. Despite their slow growth rate (possibly one micrometer per thousand years), there is evidence that these coatings capture and retain recent anthropogenic air pollutants, including heavy metals and radionuclides. To further examine this phenomenon, varnished rocks were collected in the main deposition region of airborne pollution from the coal-fired Mohave Power Plant, Laughlin, Nevada. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the major and trace elements in solutions, which resulted from stripping the varnish from duplicate samples of the substrate rock with concentrated hydrochloric acid. Thirty elements (using 34 isotopes) were determined in the strip solutions. The analytical isotopes used are: (9Be, 47Ti, 55Mn, 56Fe, 57Cr, 58Ni, 59Co, 65Cu, 66Zn, 75As, 88Sr, 98Mo, 102Ru, 103Rh, 106Pd, 114Cd, 120Sn, 121Sb, 133Cs, 138Ba, 184W, 187Re, 193Ir, 195Pt, 199Hg, 200Hg, 202Hg, 205Tl, 206Pb, 207Pb, 208Pb, 209Bi, 232Th and 238U). The highest concentrations of pollutants were observed nearest the power plant. For example, 569.4 ppm As, 1759.6 ppm Zn, 2960 ppm Pb, 21.30 ppm Hg, and 45.40 ppm Cd were found in close-in samples. The concentrations of the pollutants were found to decrease, in a regular fashion, with distance from the power plant. The platinum group elements (PGE) were also present in the varnish coatings. In addition to coal, their presence may be attributed to their occurrence in automobile exhausts. These preliminary results indicate that varnish coatings quite effectively collect and hold recent atmospherically-deposited anthropogenic pollution and that these thin films can be utilized as a passive environmental monitor.

Emerging Contaminants: Perchlorates, Pharmaceutics, and Personal Care Products
Organizer: Jacimaria Batista UNLV, Las Vegas
Organizer: Lantis I. Osemwengie USEPA, Las Vegas, Las Vegas, NV
Presider: Jacimaria R. Batista University of Nevada Las Vegas, Las Vegas, NV
Presider: Lantis I. Osemwengie USEPA, Las Vegas, Las Vegas, NV

Fouling Removal from Bioregenerated Ion-Exchange Resins Contaminated with Nitrate and Perchlorate Mohamadali Sharbatmaleki, Ph.D. Candidate, University of Nevada Las Vegas, Las Vegas, NV and Jacimaria Batista, UNLV, Las Vegas

Ion-exchange (IX) technology perhaps is the most efficient technique currently used to remove perchlorate ion from drinking waters. Despite the efficiency of IX in removing perchlorate, treatment of perchlorate-contaminated brines, and incineration/landfilling the spent resins are the major challenges to use IX technology.

A process has been developed and patented to directly regenerate IX resins contaminated with perchlorate to eliminate use of brines. The process consists of directly contacting perchlorate-contaminated IX resin with a perchlorate-reducing-microbial-enrichment-culture under anaerobic condition that results to conversion of the loaded perchlorate to chloride ion. Unfortunately, organic fouling is observed after bioregeneration. Herein we report on the efforts of fouling removal from bioregenerated resins.

For the fouling removal tests, 1000ml of field loaded resin from a well contaminated with perchlorate and nitrate was bioregenerated in a system consisting of a fluidized bed reactor and a fermentor. The resin was bioregenerated for 10days and it acquired dark coloration, characteristic of biological fouling. Two experiments were performed. The goal of experiment 1 was to determine the best solution to soak the fouled resin in prior to application of disinfectants. Experiment 2 involved disinfecting soaked fouled resin samples and reloading them with perchlorate to estimate loss in resin capacity.

Different fouling-removal and disinfectant agents were tested, and the results revealed that 12%NaCl+2%NaOH, and 12%NaCl are the best solutions to soak resin in, and NaOCl worked the best as disinfectant. Breakthrough curves obtained from loading of defouled resins showed typical characteristic curves. The fresh resin showed larger capacity than the treated resins, and the next was that of fouled resin without disinfection. This result shows that the amount of fouling has not significantly affected the resin capacity. However, relative capacity loss was observed in all resins treated with disinfectants, because disinfectants oxidize the resin and some capacity will be lost.

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Materials for Renewable Energy Applications
Organizer: Clemens Heske UNLV, Las Vegas
Presider: Clemens Heske University of Nevada Las Vegas, Las Vegas, NV

Functional Organogel of Asymmetric Bisphenazine
Dong-Chan Lee and Kelly K. McGrath, University of Nevada Las Vegas, Las Vegas, NV

The self-assembly (SA) of ?-conjugated organic semiconductors into well-defined superstructures with high aspect ratios has been one of the recent exciting research focuses due to their potential application in nanoscale optoelectronic devices. Organogels, a result of trapping solvent in a three-dimensional (3D) network of 1D nanofibers of low molecular weight organogelators (LMOGs), have shown significant advancement in recent years. Of particular interest have been functional organogels which possess specific utilities such as energy transfer, electrical conduction, etc. ?-Conjugated LMOGs have been particularly useful in generating functional organogels owing to their unique optoelectronic properties. An attractive advantage of organogelation of ?-LMOG is that it provides a facile way of producing 1D nanofibers with an effective intermolecular ?-orbital overlap which is potentially useful for 1D charge transport. However, most of the reported ?-LMOGs are p-type, while only a limited number of n-type LMOGs are available.

In this work, we report the first example of the formation of an orgnogel of an asymmetric bisphenazine through the growth of 1D nanofibers via a cooperative interplay of ?-? interaction, hydrogen bonding, and van der Waals interaction. A detailed study on gelling properties of a bisphenazine substituted with acetylene and hexadecyloxy groups with UV-Vis, XRD, FT-IR, and SEM analyses is presented. In addition, the remarkable acid sensing property of the dried gel is demonstrated.

Polyaniline/Palladium Nanocomposites: Oxidation of Alcohols in Alkaline Solutions
Nicole Millick, Jade Morgan and David Hatchett, University of Nevada Las Vegas, Las Vegas, NV

The electrochemical reduction of PdCl42- and PdCl62- into polyaniline has been demonstrated producing morphologically different PANI/Pd composites. SEM imaging demonstrates that the Pd deposits fully encapsulate the polymer for both anions studied. Although identical experimental parameters were used to deposit Pd, the PANI/Pd composites have distinctly different morphologies, Figures 1 and 2. The reduction of PdCl42- into PANI formed mesoporous Pd strands ~150 nm in length with ~10 nm diameters at the tip. In contrast PdCl62- produced PANI/Pd composites produced Pd deposits with granular morphology. The data suggests that PANI/Pd composites with high Pd metal surface area could be produced using PdCl42-. The cyclic voltammetry data showed that Pd deposition into polyaniline reduced proton doping relative to the pure polymer. This indicates that Pd deposits physically block proton uptake at nitrogen sites in the polymer. The results also suggest that the conductivity of PANI/Pd composites should be reduced. The currently accepted proton doping/ polaronic conductivity mechanism suggests that PANI/Pd composites should not be conductive in alkaline solution due to the complete lack of proton doping. However, the composites have been utilized in the electrochemical oxidation of 0.5 M methanol in solutions of 1 M KOH, Figure 3. The results suggest that there is an alternative conductivity mechanism for PANI/Pd composites, not explain using the traditional model.

Spectroscopic Characterization of Thin Films Used in Energy Conversion Devices
Marcus Bär, University of Nevada, Las Vegas, Las Vegas, NV

Energy conversion devices [such as chalcopyrite-based solar cells, photoelectrochemical (PEC) cells, or light-emitting diodes (LEDs)] often consist of thin film layer stacks. Since each layer has a different chemical and electronic structure, the interfaces between those films are (when not designed carefully) often the place of an increased density of defect states and/or a suboptimal electronic level alignment, which both can result in an increased recombination rate at the interface. In addition, interdiffusion processes can take place at interfaces, leading to significant interfacial intermixing, which induce changes in the optoelectronic properties of the whole device. Furthermore, the interfaces not only influence, but in most cases determine the local electric fields necessary for efficient charge carrier separation. Thus, the key issue for a deliberate improvement of those devices is an exact knowledge of the chemical and electronic interface structure.

Over the last few years, a combination of electron and x-ray spectroscopies has been established to gain insight into the chemical and electronic properties of interfaces. In this presentation, we will demonstrate the potential of that approach by means of several examples from the field of chalcopyrite thin-film solar cells, PEC cells, and LEDs. By deliberately using various photon and electron spectroscopies with different information depths, we will furthermore clarify that a sample surface structure might not necessarily be the same as its bulk structure. This understanding and the new insights into interfacial properties might prove very important for the future improvement of thin-film devices resulting in a reassessment of current optimization approaches.

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Poster Sessions

Organizer: Vernon Hodge UNLV, Las Vegas, NV

A Minute Surface Plasmon Resonance Imaging System for in-Situ Food Safety Detection
Shengjie Zhai1, Jun Yang1, Wensheng Hou1, Xiaolin Zheng1, Yingtao Jiang2 and Biswajit Das2, (1)Chongqing university, Chongqing, China, Chongqing, China, (2)University of Nevada, Las Vegas, Las Vegas, NV

The design, construction and application of a minute surface Plasmon resonance (SPR) imaging system for in-situ food safety detection are reported. This system consists of a compact light path, X-style junction-arm actuated by a liner actuator, and Matrix CCD to implement a high performance optical-mechanical scan imaging system in a volume 18cm x12cm x10cm. Operation angle of the imaging system is also adjusted by the junction-arm. Applications of bright diode light source and CCD detector enable real-time averaging of multiple images to improve signal-to-noise ratio. Microfluidic flow cell was positioned on the thin metal films, and used to achieve simultaneous detection of two sample streams. The obtained results demonstrate that the sensitivity of the system is about 7 x10-5 refractive index unit, and the detecting time is less than 5 min. The minute, simple construction and high performance of the imaging system meets the requirements for in-situ food safety analysis.

Measurement of Red Blood Cell Deformability in Microfluidic System Using a High-Speed Camera
Wensheng Hou1, Yanjian Liao1, Jing Yang1, Xiaolin Zheng1, Jun Yang1, Xuan Weng1, Yingtao Jiang2 and Biswajit Das2, (1)Chongqing University, Chongqing, China, (2)University of Nevada, Las Vegas, Las Vegas, NV

The deformability of red blood cell (RBC) which is one of the key blood rheology parameters was measured in a silicon-based microfluidic system using a high-speed camera. The transient motion of RBCs through a microchannel was captured using an intravital microscope equipped with a high-speed camera system, RDT16, at 500 frames/second. The obtained RBC images were analyzed using a commercial software, MiDAS 2.0, to determine kinematic parameters, and instantaneous velocities and accelerations of RBC. The RBC through a microchannel experiences deceleration at the entrance and acceleration at the exit of the microchannel. When the sizes of microchannel are 5mm in depth and 5mm in width, and pressure drop is 10cmH2O, the velocity of RBC at the entrance of the microchannel is about 0.92 mm/ms, while the minimum velocity of the RBC through the microchannel is about 0.4 mm/ms.

Synthesis and Characterization of Novel Ionic Compounds from Stilbazole Derivative
Tae K. Kim, Ontida Tanthmanatham, Alexi K. Nedeltchev, Haesook Han and Pradip K. Bhowmik, University of Nevada Las Vegas, Las Vegas, NV

Trans-4-alkoxy-4?-stilbazole derivatives have been demonstrated to exhibit various types of liquid-crystalline phases and non-linear optical properties because of their inherent chemical structural moieties present in these compounds. A series of novel ionic compounds with various inorganic and organic counterions were prepared from either the quaternization of trans-4-octyloxy-4-?-stilbazole with n-propyl iodide or the metathesis reaction of the iodide salt with the corresponding organic salts in appropriate organic solvents. Their chemical structures were confirmed with 1H and 13C NMR spectroscopy and elemental analysis. Their thermotropic liquid-crystalline properties were examined by using both differential scanning calorimetry measurements and polarizing optical microscopy studies. When compared with the trans-4-alkoxy-4?-stilbazole compound, they exhibited broad temperature range of LC phase. Interestingly enough, the ionic compound with bis(2-ethylhexyl)sulfosuccinate counterion exhibited LC phase even at room temperature. Their thermal stabilities were excellent as determined by thermogravimetric analyses in nitrogen, which were in the temperature range of 241 -357 oC. The light-emission properties of this class of ionic compounds both in various polar and nonpolar solvents were also examined by photoluminescence spectrometry.

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Boric Acid and Focal Adhesion Kinase: A Mechanism to Induce Apoptosis in Breast and Prostate Cancer Cells
Allison C. A. Wallace, M.S., M.N.S.1, Susan L. Meacham, Ph.D., R.D.1, Anu Elegbede, M.S.1, Ernesto Abel-Santos, Ph.D.1, Stephen W. Carper, Ph.D.1, Shirley Shen, B.S.1 and Ronald R. Fiscus, Ph.D.2, (1)University of Nevada, Las Vegas, Las Vegas, NV, (2)Nevada Cancer Institute, Las Vegas, NV

Focal adhesion kinase (FAK) is a 125-kDa cytoplasmic protein kinase that is over-expressed in several human cancer types, such as breast, colon and the sarcomas. Additionally, it has been identified as essential in the integrin-mediated signal transduction pathway and participates in migration, angiogenesis and inflammation/wound healing. Through chemical communication with integrins, FAK undergoes a physical conformational change, allowing autophosphorylation of its Y397 site, resulting in its active phosphorylated form, pFAK. Other research indicates that pFAK may promote cancer cell survival by its ability to suppress the signals of apoptosis, as it simultaneously promotes the signals of migration. In the Carper lab (Wallace), the presence of both FAK and pFAK has been determined in the breast cancer cell line, ZR-75-1, and the prostate cancer cell line, DU-145 [the two cancer cell lines determined by the Carper lab to be most sensitive to boric acid], by the use of the FAK ELISA assay (Activemotif). Therapeutic treatment research from the Carper lab indicates that through the use of boric acid as the therapeutic agent in both breast and prostate cancer cell lines, these cells are steered to undergo apoptosis. In current studies, we found that treatment with either fibronectin or PDGF (platelet-derived growth factor) increases pFAK levels in both cell lines. Boric acid (1mM), used as an anti-cancer agent, significantly reduced (by 4 fold) the appearance of pFAK when cells were treated with boric acid prior to their treatment with fibronectin or PDGF. Additionally, preliminary studies, using flow cytometry, indicate that boric acid seems to decrease the appearance of pFAK, while, simulataneously, increases the appearance of active caspase-3, an indication that the cells are undergoing apoptosis. The data, therefore, suggest that boric acid induces apoptosis in breast and prostate cancer cells via its ability to inhibit the autophosphorylation and activation of FAK.

Thiuronium Salts of Organic Acids: Chemistry as Art
Paul M. Forster, Ph.D., David W. Emerson, Ph.D. and Darrin L. Watts, Senior student, University of Nevada, Las Vegas, Las Vegas, NV

S-Benzylthiuronium carboxylates and sulfonates had a long history as derivatives of carboxylic and sulfonic acids before instrumental methods for identifying unknowns became common. We made thiuronium salt derivatives of a variety of organic acids and determined the crystal structures. The visual representation of these structures in some cases are startlingly beautiful and may suggest pathways to self-assembling materials of some utility.

Lab-on-a-Chip Technology: Microfluidics/nanofluidics, for Chemical and Biochemical Applications

Organizer: Shizhi Qian, Ph.D. Old Dominion University, Norfolk, VA
Organizer: Yingtao Jiang University of Nevada, Las Vegas, Las Vegas, NV
Presider: Shizhi Qian, Ph.D. Old Dominion University, Norfolk, VA

Modeling of a Spherical Particle's Motion in a Converging-Diverging Microchannel Using Arbitrary Lagrangian-Eulerian Method
Ye Ai1, Yingtao Jiang1, Shizhi Qian2 and Sang W. Joo3, (1)University of Nevada Las Vegas, Las Vegas, NV, (2)Old Dominion University, Norfolk, VA, (3)Yeungnam University, Gyongsan, South Korea

Recently, pressure-driven flows through converging-diverging microchannels have been successfully used to separate particles and stretch individual DNA molecules. The unique contraction and expansion structures have significant potential for particle analysis and manipulation.

A transient finite element model including Navier-Stoke equation, continuity equation and arbitrary Lagrangian-Eulerian (ALE) kinematics (NS-ALE) is implemented to compute the particle's velocity and track its trajectory. Code validation of the proposed NS-ALE model is performed in comparison with a reported case concerning a spherical particle's motion through a straight cylindrical microchannel. Finally, the effects of applied pressure P, particle size ratio 2r/b, throat size ratio b/(2a), where r , b and 2a denote the particle radius, the throat width and the width of straight microchannel, respectively, and particles' initial position on the particle's motion are investigated for design guidance.

As a result of the varying cross-sectional areas, the particle will experience both acceleration and deceleration processes through the converging-diverging microchannel. When the length of converging microchannel equals to that of diverging microchannel, the particle velocity profile is symmetric with respect to the throat, which demonstrates a good agreement with a reported experimental result. The ratio of the particle velocity in the throat center to that in the straight microchannel remains unchanged under different applied pressures. However, both the particle size and throat size have significant influence on the particle velocity ratio. As the particle size ratio 2r/b increases or the throat size b/(2a) decreases, the particle velocity ratio decreases. Unless a particle stays along the centerline of the microchannel, it rotates as it is translated, with a maximum spin-rate achieved at the throat. The closer is the particle located near the wall, the higher is the spin rate. Like the particle velocity profile, the spin-rate profile also shows a symmetric configuration.

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A MEMS-Based Cell Electrofusion Chip
Ning Hu1, Jun Yang1, Wensheng Hou1, Yi Cao1, Jing Yang1, Xiaolin Zheng1, Yingtao Jiang2 and Biswajit Das2, (1)Chongqing University, Chongqing, China, (2)University of Nevada, Las Vegas, Las Vegas, NV

A MEMS-based high-throughput cell electrofusion microchip has been designed, fabricated, and tested for cell fusion under a low-voltage condition. The chip consists of a microchannel with a rectangular cross section of 70um in width and 50um in height and more than 1200 pairs of silicon microelectrodes patterned along the opposing walls of the microchannel. The distance between the adjacent microelectrodes is 70um. The electrodes are then covered by an aluminum thin film of about 2um in thickness to enhance the conductivity. A thin SiO2 film (150nm thickness) film is subsequently deposited on the top face of the electrodes by plasma enhanced chemical deposition for biocompatibility. Owing to the short distance between the electrode pair, only 25 V is required to produce a high electric field up to 5.6 KV/cm. Cell-fusion experimental results showed that the cell fusion performance of the chip depends on the geometries of both the microchannel and the microelectrodes. Through optimization of the geometries, the developed chip has the features of low voltage and higher fusion efficiency.

Transient Modeling of the Electrophoretic Migration of a Spherical Particle in a Converging-Diverging Microchannel Using Arbitrary Lagrangian-Eulerian Method
Ye Ai1, Yingtao Jiang1, Shizhi Qian2 and Sang W. Joo3, (1)University of Nevada Las Vegas, Las Vegas, NV, (2)Old Dominion University, Norfolk, VA, (3)Yeungnam University, Gyongsan, South Korea

Electrophoresis, regarding to the migration of charged particles in an electrolyte solution subjected to an external electric field, has been successfully used to size and sort various biological entities in converging-diverging microchannels. Due to the nonuniform cross-sectional areas of converging-diverging microchannels, the electric field varies significantly in converging-diverging microchannels, and eventually affects the particle's migration behavior. It has already been experimentally demonstrated that particles will experience both acceleration and deceleration processes through the converging-diverging microchannels. However, less theoretical work has been done on the electrophoretic migration of a spherical particle in a converging-diverging microchannel.

A transient finite element model consisted of Navier-Stoke equation, continuity equation, Poisson's Equation and arbitrary Lagrangian-Eulerian (ALE) kinematics is implemented to predict the particle's migration behavior. First, the separation of two particles is simulated to understand the potential application of converging-diverging microchannels. Subsequently, the effects of electric field, particle size, and charging status of converging-diverging microchannel wall on the particle's electrophoretic migration are studied. Higher electric field strength leads to higher particle velocity at the throat, but the ratio of the particle velocity at the throat to that in the straight microchannel remains unchanged under different electric fields. Unlike the behavior of particles in pressure driven flows, bigger particle size results higher particle velocity ratio, since bigger particle leads to higher electric field strength at the throat. The particle and microchannel wall's charge type and the ratio of the particle's zeta potential to that of microchannel wall both have significant influence on the particle migration behavior. The particle velocity is linearly proportional to the charge ratio. Moreover, when the charge ratio equals to 1, the particle dose not move any more. Finally, the deviation between simulation results and reported data is analyzed to demonstrate the effect of dielectrophoretic force.

A Better Way of Finding Hot Particles in Soil Cores: Mapping Hot Particles with High Resolution Computed Tomography
Richard Gostic1, Julie Gostic1, Craig Bias1, Richard Ketcham2 and Kenneth Czerwinski1, (1)UNLV, Las Vegas, NV, (2)University of Texas at Austin, Austin, TX

Location and removal of hot particles from soil cores is a labor intensive process that employs a variety of manual separation and detection techniques to find the proverbial ‘needle in a haystack'. The use of hand held detectors for particle location, and removal process such as progressive sample splitting and sieving is imprecise, poses a potential contamination hazard and results in almost complete destruction of the spatial information contained within the core. Manual localization and removal procedures effectiveness are also limited by the size, specific activity and associated decay processes of the materials of interest. For example, locating weapons grade plutonium particulates is made possible by the presence of 59.5 keV gamma ray associated with the decay of 241Am. If 241Am were not present within the plutonium matrix, localizing the particles within a core would be very difficult due to the short range of the alpha particles and the low photon yields from the decay of the Pu isotopes. If we consider a particle containing 235U, a low specific activity isotope, it is likely that a small 235U particle might be ‘missed' using the same technique. High Resolution Computed Tomography (HRCT) is a fast method for hot particle localization (<5.0 hrs/core) that maintains all of the spatial information in the core while allowing the analyst to pin-point the location of high Z, high density materials with great accuracy, instead of relying on the intrinsic decay properties of the materials of interest. By combining the high spatial resolution of HRCT with conventional radioanalytical techniques we have greatly improved our ability to locate and recover hot particles from soil cores.

Study of Absorption Characteristics of Cm and Am to TEVA, TRU and DGA Resins from Different Matrices
Narek Gharibyan1, Ashlee Crable1, Steffen Happel2 and Ralf Sudowe1, (1)University of Nevada, Las Vegas, Las Vegas, NV, (2)Triskem International, Bruz, France

Separation of americium and curium has proven to be difficult due to chemical similarities between these elements. The development of separation methods for these actinides is of great importance to nuclear forensics community as well as stockpile stewardship. Efficient separations have been established, in particular for smaller quantities, using ion exchange systems based on a tertiary pyridine resin in nitric acid-methanol system or the use of cation exchange resin with ammonium α-hydroxyisobutyric acid and α-hydroxy-α-methylbutryic acid systems. Improvements in current methods and resulting separation factors are necessary to provide more accurate data. In addition, the use of an aliphatic quaternary amine has also shown to be a relatively useful method for americium and curium separation from lithium nitrate matrices. The current work explores the absorption of americium and curium to TEVA resin that contains trialkyl, methylammonium nitrate or chloride (Aliquat-336) as the active compound in batch experiments. The sorption studies are conducted from various nitrate and chloride matrices. Additionally, similar studies have also been performed with TRU and DGA resins which contain octylphenyl-N,N-di-isobutyl carbamoylphosphine oxide (CMPO) and N,N,N',N'-tetra-n-octyldiglycolamide (TODGA) as ligands, respectively.

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Proteomics in Cancer Research

Organizer: Ronald Gary University of Nevada, Las Vegas, Las Vegas, NV
Organizer: Ron Fiscus Nevada Cancer Institute, Las Vegas
Presider: Ronald Gary University of Nevada, Las Vegas, Las Vegas, NV

Chemistry, Materials Science, and Geoscience at High Pressures

Organizer: Malcolm Nicol UNLV, Las Vegas
Presider: Malcolm Nicol High Pressure Science and Engineering Center, UNLV, Las Vegas, NV

Partial Phonon Density of States of Fe Solid Solutions (Fe0.9Ge0.1, Fe0.9Pt0.1 and Fe1-xAlx) by Nuclear Resonant Inelastic X-Ray Scattering Under High Pressure

Elizabeth Tanis, Hubertus Giefers and Malcolm Nicol, High Pressure Science and Engineering Center, UNLV, Las Vegas, NV

57Fe is the most common Mössbauer isotope studied using nuclear resonant inelastic x-ray scattering (NRIXS). The phase transition of magnetic α-Fe, body-centered cubic structure, to nonmagnetic ε-Fe, hexagonal close-packed structure, occurs around 13 GPa [1]. However, by doping Fe with Ge, Pt and Al the Fe α-ε transition is shifted to higher pressures. We recently conducted experiments at the APS on beamline 16-IDD to determine how doping Fe samples with Ge, Pt and Al affects the partial phonon density of states. These experiments have allowed us to gain a better understanding of the lattice dynamics and to determine the thermodynamic properties. All of which are of great importance and interest in high pressure research as iron is the most abundant element within Earth's core.

Compression Study of Barringerite, Fe2P, up to 50 GPa
Barbara Lavina1, Przemyslaw Dera1, Lauren Borkowski2, Vitali Prakapenka1, Steve R Sutton1, Mark L Rivers1, Robert T. Downs3, Nabil Z. Boctor4, Charles T. Prewitt3 and Malcolm Nicol2, (1)University of Chicago, Argonne, IL, (2)High Pressure Science and Engineering Center, UNLV, Las Vegas, NV, (3)University of Arizona, Tucson, AZ, (4)Carnegie Institute of Washington, Washington, WA

Fe2P polymorphs, barringerite and allabogdanite, are of interest in earth and planetary sciences because of their occurrence in meteorites as precursory phases in the evolution of the solar system, and in material science because of their intriguing physical properties. Five magnetic phases have been reported in the low temperature-moderate pressure range. The present study reports compression data at quasi-hydrostatic conditions to 50 GPa at 300 K determined by means of single-crystal monochromatic diffraction at Sector 13 at the APS. The Ne pressure medium furnished a nearly hydrostatic stress field that provided data of sufficiently high quality to allow the identification of a rather complicated behavior of axial compressibility. Up to about 20 GPa, the linear compressibility of hexagonal barringerite (C22-structure type, space group ) is highly anisotropic, with the a cell edge almost twice as compressible as the c edge. The anisotropy of compression is no longer observed in the range 20-45 GPa, where the c/a ratio is constant. At the highest P achieved, 50 GPa, a significant decrease in a is counterbalanced by an increase in c while diffuse scattering perpendicular to c appears in the diffraction pattern, suggesting the occurrence of an order-disorder phase transition. Given the strong anisotropy of magnetic interactions in this phase and their strong dependence on temperature and pressure, it is likely that the unusual variations in the linear compressibility with pressure, along with the ordering changes, are related to variations in the material physical properties, or even to magnetic phase transitions. Fe is documented to undergo a high-spin to low-spin transition at high pressure in many compounds. It is likely that the phenomena we observe at 50 GPa are due to the structural rearrangement resulting from a variation in the size and symmetry of the Fe coordination sphere induced by the spin transition.

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Polymer Architecture II

Organizer: Pradip K. Bhowmik University of Nevada Las Vegas, Las Vegas, NV
Presider: Pradip K. Bhowmik University of Nevada Las Vegas, Las Vegas, NV

Synthesis and Characterization of Poly(pyridinium salt)S with Quinoline Moieties Exhibiting High Thermal Stability, Excellent Solubility, and Photoluminescence
Alexi K. Nedeltchev, Haesook Han and Pradip K. Bhowmik, University of Nevada Las Vegas, Las Vegas, NV

Six novel poly(pyridinium salt)s with quinoline moieties in their main chain with bulky tosylate and triflimide counterions were prepared by ring-transmutation polymerization of phenylated bis(pyrylium tosylate) salt with a series of isomeric quinoline diamines in dimethyl sulfoxide for at 120-130 °C 48 h and metathesis reaction from the corresponding tosylate polymers with lithium triflimide in dimethyl sulfoxide at 50 °C for 48 h. Their chemical compositions and structures were confirmed by elemental analyses and 1H and 13C NMR spectroscopy, respectively. They show high thermal stabilities in the range of 353-359 °C for the tosylate containing polymers and 440- 455 °C for the triflimide containing ones. Even though they are highly conjugated polymers, they possess excellent solubility in common organic solvents such as methanol, acetone, acetonitrile, and dimethyl sulfoxide. Their light-emitting properties were studied by using spectrofluorometry. They exhibited photoluminescence properties in solutions shifting bathochromically from blue (λem at ca. 453 nm) to green (λem at ca. 497 nm) on changing from less to more polar solvents.

Synthesis and Characterization of Poly(pyridinium salt)S with Pyridine Moieties Exhibiting High Thermal Stability, Excellent Solubility, and Photoluminescence
Alexi K. Nedeltchev, Haesook Han and Pradip K. Bhowmik, University of Nevada Las Vegas, Las Vegas, NV

Six novel poly(pyridinium salt)s with pyridine moieties in their main chain with bulky tosylate and triflimide counterions were prepared by ring-transmutation polymerization of phenylated bis(pyrylium tosylate) salt with a series of isomeric pyridine diamines in dimethyl sulfoxide for at 120-130 °C 48 h and metathesis reaction from the corresponding tosylate polymers with lithium triflimide in dimethyl sulfoxide at 50 °C for 48 h. Their chemical compositions and structures were confirmed by elemental analyses and 1H and 13C NMR spectroscopy, respectively. They show high thermal stabilities in the range of 340-364 °C for the tosylate containing polymers and 427- 458 °C for the triflimide containing ones. Even though they are highly conjugated polymers, they possess excellent solubility in common organic solvents such as methanol, acetone, acetonitrile, and dimethyl sulfoxide. Their light-emitting properties were studied by using spectrofluorometry. They exhibited photoluminescence properties in solutions shifting bathochromically from λem at ca. 466-481 nm on changing from less to more polar solvents.

Poly(pyridinium salts) Derived from 2,2?-Bis(trifluoromethyl)-4,4?-Diaminobiphenyl: Liquid-Crystalline and Photoluminescence Properties
Pradip K. Bhowmik, Haesook Han and Alexi K. Nedeltchev, University of Nevada Las Vegas, Las Vegas, NV

The 2,2?-bis(trifluoromethyl)4,4?-diaminobiphenyl (TFDB) is an important monomer for the synthesis of many functional polymers. Polyamides and polyimides are two major classes of such polymers. The presence of two trifluoromethyl groups located at 2 and 2? positions of the biphenyl moiety increases not only the thermal stability but also the solubility of a specific polymer in many common organic solvents because of the noncoplanarity of this moiety. Two poly(pyridinium salt)s with TFDB moieties in the main chain as well as tosylate and triflimide as counterions were prepared either by the ring-transmutation polymerization of phenylated bis(pyrylium tosylate) salt with TFDB in dimethyl sulfoxide (DMSO) or the metathesis reaction of the corresponding tosylate polymer with lithium triflimide in a common organic solvent. Their chemical structures were determined by 1H NMR and elemental analyses. Their weight-average molecular weights were 53 000 and 68 000, and polydispersity indices were 1.23 and 1.45, respectively, as determined by gel permeation chromatography using DMSO as a solvent. Their hydrodynamic radii in this solvent measured at 70 °C were 10.46 and 10.60 nm, respectively. Additionally, their Mark-Houwink α values were 1.44 and 1.31, and K values were 2.36 x 10-7 and 9.95 x 10-6, respectively, in DMSO at 70 °C. Both thermotropic and lyotropic liquid-crystalline (LC) properties of these polymers were examined by using differential scanning calorimetry and polarizing optical microscopy. Since these polymers exhibited LC phase both in the melt states and in solutions, they can be appropriately classified as amphotropic class of ionic polymers. Their light-emitting properties in various organic solvents were also determined by using luminescence spectrometer.

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Poly(pyridinium salts) Derived from ?,?-Diaminoalkanes: Thermotropic Liquid-Crystalline and Photoluminescence Properties
Pradip K. Bhowmik, Haesook Han and Alexi K. Nedeltchev, University of Nevada Las Vegas, Las Vegas, NV

Several poly(pyridinium salts) with tosylate as counterions were synthesized by the ring-transmutation polymerization of phenylated bis(pyrylium tosylate) with ?,?-diaminoalkanes on heating in dimethyl sulfoxide (DMSO) for 24 h. The ?,?-diaminoalkanes used in this study were 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,10-diaminodecane and 1,11-diaminoundecane. From these polymers, several other poly(pyridinium salts) containing triflimide as counterions were prepared by the metathesis reaction of these corresponding tosylate polymers with lithium triflimide in a common organic solvent. Their chemical structures were confirmed with 1H and 13C NMR spectroscopy and elemental analyses. Their weight-average molecular weights were in the range of 14 000 -19 000, and polydispersity indices were in the range of 1.19-1.63 as determined by gel permeation chromatography using DMSO as a solvent. Their hydrodynamic radii in this solvent measured at 70 °C were in the range of 2.14-3.02 nm. Additionally, their Mark-Houwink ? values were in the range of 0.89-1.20 and K values were in the range of 1.05 x 10-6-1.12 x 10-5 in DMSO at 70 °C. They were examined for their thermotropic liquid-crystalline (LC) properties using various experimental techniques. They exhibited smectic LC phases at relatively low temperatures as determined by both differential scanning calorimetry and polarizing optical microscopy studies because of the presence of flexible alkylene units present in their backbones. Some of them also transformed from smectic-to-isotropic liquid phase on further heating at higher temperatures on the hot-stage, which were much lower than their decomposition temperatures. Their light-emitting properties in various organic solvents by using luminescence spectrometer were also included in this study.

The Effect of Alloying on CO Tolerance of Pt Nanoparticles
T. J. Dhilip Kumar, P. Tarakeshwar and N. Balakrishnan, University of Nevada Las Vegas, Las Vegas, NV

Platinum is the most widely used catalyst in fuel cell electrodes. Pure Pt is highly susceptible to CO poisoning and designing improved catalysts with low CO tolerance is one of the grand challenge in fuel cell research. Experimentally, Pt3Ti bimetallic system is known to have high resistance for CO tolerance by 20% compared to pure Pt system. We have performed density functional studies of CO adsorption on small Pt3M and PtM3 clusters where M=3d block elements or Ru. The calculations were performed using the DMol3 code within the generalized gradient approximation and the Perdew-Wang exchange-correlation functional. The chemisorption energy was found to be the lowest for the Pt-Ti system which indicates that CO binding is more tolerant in Pt-Ti system due to larger charge partitioning between Pt and Ti in Pt3Ti and PtTi3 systems. The Pt-Ti system is also characterized by much larger HOMO-LUMO energy gap.

Biodefense and Emerging Pathogen

Organizer: Ernesto Abel-Santos UNLV, Las Vegas
Presider: Ernesto Abel-Santos University of Nevada Las Vegas, Las Vegas, NV

Session Overview: The use of endemic pathogens as bioweapons and the emergence of new infectious diseases posses a real threat to the welfare of the general population. Countering these threats require the coordinated efforts of the scientific community. This session will examine the role of Chemistry and Biochemistry in studying biodefense-relevant and emerging pathogens. Presentations will include use of chemical and biochemical tools for the detection, monitoring, and treatment of significant infective agents.

Synthesis and Characterization of Thermotropic Liquid-Crystalline Azomethine Dimers
Hari D. Mandal1, Pradip K. Bhowmik2, Haesook Han2, Alexi K. Nedeltchev2, Jose A. Jimenz-Hernandez1, Patrick M. McGannon1 and Leonardo Lopez1, (1)Texas A & M International University, Laredo, TX, (2)University of Nevada Las Vegas, Las Vegas, NV

Azomethine (-N=CH-) is an important functional group in organic chemistry, which is the connecting group of making many functional organic compounds as well as polymers. For examples, many suitably designed azomethine compounds and polymers exhibit thermotropic liquid-crystalline properties. The synthesis of azomethine compounds usually involves the reaction between primary amines and aldehydes, which requires mild reaction condition with high yield. A series of azomethine dimers were prepared by the reaction of benzaldehyde, 4-phenylbenzaldehyde and 9-anthraldehyde with either 1,6-bis(4-aminophenyl-4?-oxy)hexane or 1,9-bis(4-aminophenyl-4?-oxy)nonane on heating to reflux in toluene in presence of tosic acid. Their chemical structures were established with IR, 1H and 13C NMR and elemental analysis. Their thermotropic liquid-crystalline properties were examined by using differential scanning calorimetry and polarizing optical microscopy studies. The azomethine dimer prepared from 4-phenylbenzaldehyde 1,6-bis(4-aminophenyl-4?-oxy)hexane showed a crystal-to-liquid-crystalline phase transition (Tm) at 267 °C, which then transformed into another liquid-crystalline phase at 296 °C. The second liquid-crystalline phase persisted up to its decomposition temperature. Their thermal stabilities were determined by thermogravimetric analyses as the temperatures in °C at which the loss of 5% wt of compounds occurred in nitrogen and found to be in the range of 307-367 °C.

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Synthesis, Optical, and Thermal Properties of Conjugated, Quinoline Diamines by Friedländer Condensation Reaction
Alexi K. Nedeltchev, Haesook Han and Pradip K. Bhowmik, University of Nevada Las Vegas, Las Vegas, NV

A series of conjugated quinoline diamines were synthesized by two-step method. Friedländer condensation of 2-amino-5-nitro-benzophenone with 2?-nitroacetophenone and its isomers in presence of sulfuric acid in acetic acid medium for 5 h at reflux produced the 6-nitro-2-(2-nitrophenyl)-4-phenyl quinoline and its isomers in excellent yields. They were subsequently reduced with hydrazine over Pd/C in ethanol solution to produce the desired 6-amino-2-(2-aminophenyl)-4-phenyl quinoline and its isomers. Their chemical structures were confirmed by elemental analyses and 1H and 13C NMR spectroscopy. Their optical and thermal properties were examined by using UV-vis and luminescence spectrometers and differential scanning calorimetry, respectively. All of the quinoline diamine compounds were photoluminescent, emitting violet to blue light, in solvents such as toluene, chloroform, tetrahydrofuran, methanol and acetonitrile. In each case, a bathochromic shift was observed when solvent polarity was changed from less to more polar solvents. For example, the 6-amino-2-(2-aminophenyl)-4-phenyl quinoline exhibited an λem at ca. 426 nm in toluene at excitation wavelength of 355 nm, but it exhibited an λem at ca. 460 nm in methanol at excitation wavelength of 355 nm.

Synthesis and Characterization of Thermotropic Liquid-Crystalline Properties of 4,4?-Dialkoxy-3,3?-Diaminobiphenyl Compounds
Cynthia Wade, Junwen Lin, Tae K. Kim, Bidyut Biswas, Haesook Han and Pradip K. Bhowmik, University of Nevada Las Vegas, Las Vegas, NV

Several 4,4?-dialkoxy-3,3?-diaminobiphenyl compounds were synthesized by adopting three-step procedure starting from 4,4?-biphenol. The three steps involved were the alkylation of 4,4?-biphenol with alkyl bromide, nitration in acetic acid, and reduction by stannous chloride/concentrated hydrochloric acid in ethanol. The alkyl bromides used were n-bromohexane, n-bromoheptane, n-bromooctane and 2-ethyl-1-bromohexane. All of 3,3?-diaminobiphenyl derivatives including their intermediates were characterized for their purity by 1H, and 13C NMR and elemental analyses. All of the 4,4?-dialkoxy derivatives of 3,3?-dinitrobiphenyl and 3,3?-diaminobiphenyl were examined for their thermotropic liquid-crystalline (LC) properties by using differential scanning calorimetry (DSC) and polarizing optical microscopy studies (POM). The 4,4?-hexyloxy-3,3?-diamine showed a crystal-to-liquid-crystalline transition (Tm) at 85 °C and liquid-crystal-to-isotropic liquid transition (Ti) at 106 °C in both the heating cycles of its DSC thermograms. It had a temperature range of LC phase of 21 °C. Its LC phase was found to be either SA or SC since it exhibited the so-called bâtonnets texture as determined by POM. All of these diamines were targeted for the synthesis of various classes of polymers including poly(pyridinium salt)s having solubility in common organic solvents.

Mercury Content of Tobacco Products by Means of Automated Combustion Amalgamation Atomic Absorption Spectrometry
Yogendra M. Panta, Youngstown State University, Youngstown, OH, Shizhi Qian, Old Dominion University, Norfolk, VA, James V. Cizdziel, University of Mississippi, University, MS and Chad L. Cross, University of Nevada Las Vegas, Las Vegas, NV

A commercially available mercury (Hg) analyzer (AMA-254), comprises of sample combustion, gold amalgamation, and atomic absorption spectrometry (AAS), was analyzed and optimized for the direct determination of total-Hg content in three common tobacco products: cigarettes (n=30; 5 lights, 5 regulars for 3 brands), cigars (n=4; 1 brand) and chewing tobacco packets (n=5; 1 brand). This method is advantageous for the ease of use (automated analysis with no sample preparation), rapid analysis (<10 min per sample), and a low detection limit (0.04 ng of Hg). The accuracy was evaluated with certified reference materials (Virginia Tobacco Leaves and Tomato Leaves) and samples spiked with NIST SRM 1573a. Relative standard deviation (RSD) for each tobacco sample was <12%. Both mercury content and concentration (fresh weight basis) was observed highest in the cigar (54.7 ± 6.0 ng/cigar; 20.8 ± 1.0 ng/g), followed by cigarettes (11.7 ± 1.2 ng/cigarette; 13.0 ± 1.3 ng/g) and chewing tobacco (4.4 ± 0.5 ng/packet; 6.3 ± 0.6 ng/g). Moisture content was highest in chewing tobacco (54.8%), followed by cigarettes (12.1%) and cigars (6.2%). The tobacco and filler of the cigarettes contributed for >97% of the Hg found in the whole cigarette. Mean concentrations of Hg between the individual brands of cigarettes and between the “light” and “regular” designations were not significant, and chewing tobacco did not differ significantly from most cigarette brands; however, cigars contained significantly higher of Hg. Hg content of saliva obtained before and during use of chewing tobacco did not show significant differences. Overall, this study demonstrates that analyzers based on combustion-amalgamation-AAS are suitable and sensitive for monitoring mercury levels in tobacco products.

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Treatment of Residual Ion-Exchange Brines Containing Chromium
Behrang Pakzadeh, PhD Student and Jacimaria R. Batista, Associate Profes, University of Nevada Las Vegas, Las Vegas, NV

On 1992, a maximum contaminant level (MCL) of 0.1 ppm (parts per million) for chromium became effective from the US EPA. Significant research efforts have been spent on technologies to remove chromium from drinking waters. Coagulation/Filtration, ion exchange, reverse osmosis, and lime softening have been investigated by many scientists. The abovementioned technologies are very successful in producing water with chromium levels below the required MCL. However, these technologies produce residual waste streams that must be managed.

Ion Exchange with strong-base anionic resins has been confirmed to be very effective to remove chromium from drinking waters. This technology has the capability to lower chromium level in drinking waters to part per billion (ppb) levels which are much lower than the present chromium MCL. However, the waste residual brines generated in the process should be treated before to disposal because the produced brine is considered hazardous waste. The brines containing chromium level greater than 100 x the drinking water standard is considered hazardous. The further treatment of chromium with calcium polysulfide reduces the volume of generated hazardous waste and also minimizes the risk of recontamination of the environment. Ion-exchange generated brines contains chromium concentrations ranging from 5 to 100 mg/L, alkalinities of 20-200 meq/L, sulfate concentrations of 100-1000 meq/L, and pH values ranging from 8-10.

The removal of chromium from synthetic ion exchange brines is studied in the current research. Chemical precipitation, adsorption, and reduction of chromium using calcium poly sulfide are investigated. The application of calcium polysulfide to remove chromium from water with typical total dissolved solids concentrations (TDS) is well known. However, chromium removal from brines has not been fully investigated to date. A series of jar tests was performed to determine required calcium poly sulfide dosages and pH changes. Complete chromium removal was obtained using calcium poly sulfide.

Biodefense and Emerging Pathogen

Organizer: Ernesto Abel-Santos University of Nevada Las Vegas, Las Vegas, NV
Presider: Ernesto Abel-Santos University of Nevada Las Vegas, Las Vegas, NV

Session Overview: The use of endemic pathogens as bioweapons and the emergence of new infectious diseases posses a real threat to the welfare of the general population. Countering these threats require the coordinated efforts of the scientific community. This session will examine the role of Chemistry and Biochemistry in studying biodefense-relevant and emerging pathogens. Presentations will include use of chemical and biochemical tools for the detection, monitoring, and treatment of significant infective agents.

Structure: Function Analysis of a Family of Bacterial Outer Membrane Proteases
Eun-Hae N. Kim, Sara Kienzle, Christian A. Ross and Helen J. Wing, University of Nevada, Las Vegas, Las Vegas, NV

Omptin proteases are found in many important bacterial pathogens including ,Yersinia pestis and pathogenic E. coli, Salmonella, and Shigella species. These proteases are embedded in the outer membrane of these bacteria, placing them at the bacterial-host interface during infection. High levels of amino acid sequence identity, the surface exposed nature of these bacterial proteins and their unique structure, raises the profile of omptins proteases as possible drug targets. It remains unclear, however, whether these proteases share similar activities or whether small changes in their amino acid sequence has led to different activities. Here, we compare the structure and function of two members of the omptin family; IcsP of Shigella flexneri and PgtE of Salmonella enterica. Our data reveal that the activity of IcsP and PgtE differ in their ability to cleave a known substrate called IcsA, to protect the bacterium from a human cationic antibacterial peptide, LL37, and to promote adhesion to basement membranes. Since lipopolysaccharide (LPS), a major component of the outer membrane of gram-negative bacteria is required for the activity of the omptin protease OmpT, we reasoned that different kinds of LPS may influence omptin activity. To address this, omptin-switching experiments were conducted. The result of these experiments reveals that the difference in activity of IcsP and PgtE is an inherent property of the protease rather than an effect of the surrounding LPS environment. In silico analyses reveal that the difference in the activity of these two proteases is most likely caused by subtle changes in the length and amino acid composition of loops surrounding the active site residues. Site-directed mutagenesis directed at these loops will address this.

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Bacillus Cereus Spores Secrete Amino Acids That Synergize with Inosine to Promote Germination
Tetyana Dodatko1, Monique Akoachere2, Stefan Muehlbauer1, Christian Ross2, Jurgen Brojatsch1 and Ernesto Abel-Santos2, (1)Albert Einstein College of Medicine, Bronx, NY, (2)University of Nevada Las Vegas, Las Vegas, NV

Members of the Bacillus cereus group of bacteria form endospores that respond differentially to small molecule germinants. B. cereus 569 spores are able to germinate in the presence of inosine as a sole germinant. However, inosine-treated B. cereus spores germinated only after a significant lag period, which was dramatically reduced when inosine was supplemented with supernatants derived from germinated spores. Supernatants obtained from germinated B. cereus spores contained inosine, dipicolinic acid, calcium, and amino acids, including D and L-alanine. Inosine-treated B. cereus spore germination accelerated in the presence of alanine concentrations found in supernatants from germinated spores. Inosine-induced germination was also significantly increased in the presence of the alanine racemase inhibitor, D-cycloserine, which increases the concentration of active L-alanine. On the other hand, gerI and gerQ-deficient B. cereus spores, which failed to germinate in the presence of inosine, did not release amino acids following inosine exposure. These mutant spores, however, germinated like wild type spores when inosine was supplemented with alanine. Finally, B. cereus spores failed to germinate in the presence of inosine as a sole germinant when released amino acids were immediately removed in washout experiments. Taken together, our results suggest that amino acid release is important for inosine-mediated germination of the B. cereus spore population. Based on our findings, we postulate a two-tier mechanism for inosine-mediated germination of B. cereus: Inosine triggers the release of amino acids with alanine as a major component, which then synergizes with inosine to trigger gerI/gerQ-independent germination.

A Phylogenetic Analysis of the Ger Family of Germination Receptors
Christian A. Ross and Ernesto Abel-Santos, University of Nevada Las Vegas, Las Vegas, NV

In response to nutrient-limiting conditions, Bacillus anthracis and other related Gram-positive soil organisms, such as Clostridium spp., have the capability to form a specialized dormant endospore cell-type that is exceptionally resistant to environmental stress. Usefulness of this survival strategy requires an efficient means of germinating and resuming vegetative growth on detection of more favorable environmental conditions. We have been interested in the germination process since B. anthracis spores are the infective unit and germination is the first step for establishing anthrax infection. The initial step of the germination signaling pathway, recognition of single germinant by a geminant receptor, is encoded by tri-cistronic gerA operon homologues(2).

We have constructed phylogenetic trees on the basis of full-length amino acid sequences for each of these proteins and identified conserved motifs that identify individual receptor lineages. The motif analysis, conducted using the MEME/MAST system(1), suggests possible protein regions that may be important for substrate recognition. We observe that GerAB homologues form several paralogous and orthologous groupings that identify major evolutionary events in the development of the varied germinant responses. Our preliminary results show that GerAA, GerAB and GerAC homologues coevolved thus suggesting interactions between all three proteins. Furthermore, we note that alanine responsiveness appears to form a nested clade within germination receptor subfamilies suggesting it as an ancestral germinant.

Transcription-Associated Mutagenesis in Bacillus Subtilis
Christine Pybus, MSc, Ronald Yasbin, PhD and Eduardo A Robleto, University of Nevada, Las Vegas, Las Vegas, NV

Stationary phase mutagenesis is a process by which non-dividing cells acquire potentially beneficial mutations as a response to stress. Although the generation of adaptive mutations is essentially stochastic, many studies in both Escherichia coli and Bacillus subtilis have demonstrated that genetic processes are involved in this phenomenon. Here we demonstrate in an experimental construct how transcription influences the accumulation of adaptive mutations. We placed a mutated allele, leuC427, under the control of an inducible promoter and assayed the level of Leu+ reversion in conditions of leucine starvation. Our results demonstrate that, in the presence of inducer, reversion to leucine prototrophy increased significantly. Since transcription is a ubiquitous biological process the transcription-associated hypothesis is relevant to the generation of mutations in diverse organisms. Stationary phase mutagenesis can provide a strategy for escape from growth-limiting conditions, as well as contribute to evolutionary processes

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Electrodeposition of Radionuclides Under Magnetohydrodynamic Convection for Alpha Spectrometric Determination
Yogendra M. Panta, Youngstown State University, Youngstown, OH, Dennis E. Farmer, University of Nevada, Las Vegas, Las Vegas, NV, Marcos A. Cheney, Cheney, University of Maryland Eastern Shore, Princess Anne, MD and Shizhi Qian, Old Dominion University, Norfolk, VA

In recent years, alpha spectrometry has received renewed interests due to global terrorism and in preparing thin layer sources required for high quality alpha spectrometric determination. Thin layer source prevents the self-absorption of alpha particles during the analysis of alpha sources. Several methods were reported in the literature for the electrodeposition of radionuclides, however, such methods are not convenient and effective. The novel approach of electrodeposition coupled with MHD fluid convection for the preparation of mixed radionuclides sources such as: 238U, 234U, 239Pu, and 241Am sources is developed.

The deposition rate of radionuclides was linearly increased with the magnitude of the magnetic flux density due to the increased ionic mass transport in the diffusion layer near the surface of the steel planchet by the action of the induced Lorentz forces. During the electrodeposition of radionuclides onto the cathodic surface under a MHD fluid convection, a constant current density through the aqueous solution was maintained using a potentiometer. The orthogonal interaction between the resulting current density and the external magnetic flux density induces Lorentz forces which ultimately generate fluid motion and act as a stirring action in the solution. The detection sensitivities of the radionuclides with supporting electrolytes are enhanced and are proportionally electrodeposited from the mixed radionuclides solution. The deposition conditions for electroplating radionuclides have been locally optimized for experimental parameters such as constant current of 0.5 A, pH range of 2 to 2.3, deposition time of 60 min, and a higher magnetic flux density of 0.71 T. This modified MHD electrodeposition method made it possible to prepare ultra thin layer, uniform alpha particle sources and better resolution under reproducible conditions. The detection sensitivity was enhanced by about 30 % with the use of MHD convection.

A Field Screening Technique for the Detection of Alpha-Emitting Radionuclides
Dennis E. Farmer1, Vernon F. Hodge1 and Jeffrey Tappen2, (1)University of Nevada, Las Vegas, Las Vegas, NV, (2)Desert Research Institute, Las Vegas, NV

Researchers at the University of Nevada, Las Vegas (UNLV) are conducting preliminary tests of a novel detection method for screening air particulate samples for alpha radiation in the field. Alpha-emitting species are a particularly dangerous form of radioactivity from a health perspective as they often have long half-lives and are only slowly cleared from the body. The method is designed to detect the presence of anthropogenic and/or technologically-enhanced alpha-emitting radionuclides, like plutonium, in the air. The goal is to identify contaminated samples as early as possible, so they can be subjected to more detailed follow-up analyses. When fully developed and implemented, this research is expected to reduce the costs incurred from performing the numerous and often unnecessary radiochemical analyses done before a site is considered cleaned-up. Extension of the technique under investigation will also allow screening for a broader range of alpha contaminants during emergencies and remediations, including depleted and enriched uranium (DU and EU). The technique, referred to as Spectral Deformation Analysis (SDA), exploits the concept that the characteristic alpha-emissions from man-made/technologically enhanced radionuclides, although frequently masked by naturally-occurring, higher-energy alpha-emitting radionuclides, impact the shape of the broad-energy alpha spectrum emitted from the surface of an air filter or contamination swipe in a predictable way. Assessment data is collected by defining several key comparison regions of the total alpha spectrum and analyzing a series of short sequential measurements made over a period several hours. Conventional, solid-state alpha detection equipment calibrated over an energy range of ~ 3 MeV to 9 MeV is utilized. Statistical techniques are then used to process and interpret the data, allowing a first approximation of the presence or absence of the alpha–emitting radionuclides of interest and an estimate of their airborne concentrations.

Plutonium Isotopes in Desert Varnish near the Nevada Test Site -NTS
Kenneth A. Hoar, Office of River Protection, Livermore, CA, James V. Cizdziel, University of Mississippi, University, MS, Mary Turner, University of Nevada, Las Vegas, Las Vegas, NV, Klaus J. Stetzenbach, University of Nevada Las Vegas, Las Vegas, NV and Vernon Hodge, UNLV, Las Vegas, NV

From 1951 to 1962, the United States conducted 100 above-ground nuclear weapons tests at the Nevada Test Site (NTS), located 100 miles northwest of Las Vegas. Although there is one value for plutonium in desert varnish in the literature, it reports the radioactivity of plutonium, Pu-239+Pu-240, and does not provide any information on the masses of the isotopes. Radioactive fallout from the NTS has a relatively low Pu-240/Pu-239 mass ratio of about 0.03, compared to the ratio in global fallout, about 0.18. The question arose, what is the Pu-240/Pu-239 mass ratio in desert varnish samples located in the fallout plume, or downwind, compared to that in those collected upwind, in sites south of Las Vegas? Rock samples were collected and the varnish stripped from the surface of the rocks with concentrated hydrochloric acid. The solutions were counted by high-purity germanium gamma ray spectroscopy and the plutonium was isolated by a two-column anion exchange procedure to minimize the interferences from uranium (U-238 hydride is isobaric with Pu-239). The plutonium isotopes were determined by high-resolution SF-ICPMS. The samples of varnish from rocks collected downwind at Queen City Summit, about 40 miles north of the NTS, have the lowest Pu-240/Pu-239 mass ratios of about 0.06, clearly dominated by plutonium from the NTS. These results indicate that the very slow-growing varnish films collect and hold NTS-generated fallout that bathed the varnished surfaces, for probably less than 100 days over a ten-year period, or, a mere point in the life of the several-thousands-of-years-old varnish. The upwind samples have isotope ratios from 0.13 to 0.18. The gamma ray analyses are also presented.

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General Chemistry Papers

Organizer: Kazumasa Lindley University of Nevada Las Vegas, Las Vegas, NV
Presider: Kazumasa Lindley University of Nevada Las Vegas, Las Vegas, NV

High Pressure Studies of 1,3,5,7-Cyclooctatetraene and Cyclopentane: Experiment and Theory
Sergey N. Tkachev, Ph.D., Michael Pravica, Ph.D., Eunja Kim, Ph.D., Edward Romano and Philippe F. Weck, Ph.D., University of Nevada, Las Vegas, Las Vegas, NV

High pressure studies of 1,3,5,7-cyclooctatetraene (COT) and cyclopentane have been carried out using Raman spectroscopy up to 16 GPa and 21 GPa for COT and cyclopentane, respectively, with samples loaded in the Mao-Bell type of diamond anvil cell. Experimental results were complemented by density functional calculations and molecular dynamics study (for COT). Angular-dispersive X-ray diffraction pattern taken at 3.8 GPa and room temperature shows that the crystalline symmetry of the solid COT is orthorhombic with the space group, Aba2, and the lattice constants of 6.73(1) Å, 6.726(3) Å and 9.72(1) Å, which is in good agreement with theoretical results of 6.814 Å, 6.993 Å and 9.859 Å. At least, two phase transitions were observed in COT and cyclopentane during pressure increase followed by the loss of the long-range crystallographic order (for COT), which was also associated with a strong pressure-induced luminescence that allowed estimation of band gap alterations in COT and its reaction end product with pressure. Single crystals of cyclopentane were grown in the diamond anvil cell upon decompression.

Identification of Pervasive Student Conceptions of the Central Dogma and Implications for the Development of a Concept Inventory
Thomas J. Bussey and MaryKay Orgill, University of Nevada, Las Vegas, Las Vegas, NV

The development of a concept inventory involves the preliminary identification of pervasive student conceptions within the field. In order to gain an understanding of students' conceptions of the central dogma, an initial survey was developed in which college-level biochemistry students were asked to display their knowledge of the processes of DNA replication, RNA transcription, and protein synthesis. Generally, students were able to identify the major components and events of the central dogma; however, their explanations greatly oversimplified or ignored the molecular mechanics that facilitate this process. In this poster presentation, the results of the current pilot study will be presented. Students' conceptions of the central dogma will be compared to current literature through an analysis of commonly used biochemistry texts. Next steps in the development of a central dogma concept inventory will also be discussed.

Cells in the 'hood'
Rebecca Reichenbach, West Preparatory Institute (HS), Las Vegas, NV Teaching students about cells through analogies related more closely to their experiences than the typical ones in textbooks.

Graphic Organizers for Vocabulary Acquisition
Shelly Holt, West Preparatory Institute (HS), Las Vegas, NV

This project was a study to determine if various graphic organizers, used in conjunction with three dimensional (3-D) “foldables” suggested by the textbook, would increase science language acquisition. I considered several pieces of data to answer my basic question: "How will the use of graphic organizers affect language acquisition in the Biology I science classroom?" The classes were heavily populated by language learners (LL). There were also many students who are living in lower socio-economic settings and who are reluctant readers, possibly due to not having access to academic reading materials outside of the school. Both groups have similar language acquisition problems, though the non-LL students are less likely to have problems with English used for recreational and fictional reading.

Understanding the Urban Heat Island Effect
Shelly Holt, Rebecca Reichenbach and Christopher Smith, West Preparatory Institute (HS), Las Vegas, NV

Due to the unique placement of Western HS within a "concrete and asphalt island" and the construction projects to rebuild it, we became interested how the new construction would affect our urban heat island "footprint." We tracked the construction and changes with the students over a two year time frame. We used three inquiry-style labs to teach the students about heat concepts and affect of heat islands. We also used a misconceptions survey at the beginning and end to determine changes in student understanding. along with student journalling of the three labs. We found significant conceptual change in the grade 9 students, with less significant change for the older student population

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Empowering Students for Science with An Interactive Notebook
Cheryl Waldman, Frank Messina, Jami Spencer and Sheila Curva, Palo Verde High School, Las Vegas, NV

An interactive notebook is a tool in which students actively engage with new information. When using an interactive notebook students emphasize and demonstrate their thinking, prior knowledge, and misconceptions. The notebooks provide students with an opportunity to create representations of understanding that demonstrate their learning. In an action research project students indicated that the interactive notebook affected their attitude toward science in an unmistakably positive and that the interactive notebook greatly affected their organizational skills.

Student Generated Analogies as a Learning Strategy for Students with Special Needs
Cindy Kern, Green Valley High School, Henderson, NV

Analogies provide a tie to experiences and prior understanding, making learning something new, less intimidating. From personal experience, I have found that students willingly embrace analogies as a means for fostering their growing understanding of the world around them. This willingness, i.e. student motivation, provides me, as a teacher, the opportunity to implement analogies as a learning strategy for science. When I made the connection between analogies and motivation, I realized the connection to students with special needs. Every population of students has special needs. So for this paper students with special needs are defined as students with Individualized Education Plans (IEP), Federal 504 Accommodation Plans (504) and/or English Language Learners (ELL). Many times the focus, in terms of strategies, for students with special needs is behavioral. The objective is to teach the student how to act in the social context of a classroom. Over the years, I have found that students who are engaged in science require less teacher attention because of their behavior. Teaching analogies as a self-regulatory strategy will benefit all of my students, but the familiarity, the positive reinforcement for motivation, and the tie analogies can make to student lives and their experiences provide a great SRL strategy for all students, especially those with special needs. Therefore, the purpose of this action research was to engage students in a self-regulatory, student friendly strategy in order to help facilitate student learning. Further, this project includes a particular focus on students with special needs.

Improving English Language Learner's Understanding of Science through Varied Vocabulary Instruction
Laura Doughty, Desert Pines High School, Las Vegas, NV

Desert Pines High School in Las Vegas, Nevada has a large Hispanic population. A section of the student body has at one point or another been enrolled in the English Language Learner (ELL) program during their careers as students in the Clark County School District. For the 2007-2008 school year, three Environmental Science classes taught by the researcher were the subject of a study on varied instructional techniques for learning science vocabulary.

Game on! Learning Cell Biology with Nanolegends
Frank Messina and Jami Spencer, Palo Verde High School, Las Vegas, NV

In the perpetual quest to find pedagogy that motivates students to learn in a more meaningful and effective manner, this research project incorporated the use of a video game for cell science instruction. Students in tenth grade Biology classes used Nano Legends®, an inventive and stimulating video game, to learn about the science of cells and cancer. The overarching theme of this action research project is that cell based game instruction will have similar effects on students as does standards based instruction in the classroom. Both interpretive and quantitative approaches were used to analyze the various data sources to answer the research questions. Our findings suggest that there are very positive aspects of gaming instruction but it may be best to complement direct instruction with this modality. Pairing of students with limited gaming experience with experienced game players is needed to afford all students an equal learning opportunity.

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Education Poster Session - Undergraduate Chemistry Research

Organizer: MaryKay Orgill University of Nevada, Las Vegas, Las Vegas, NV
Presider: MaryKay Orgill University of Nevada, Las Vegas, Las Vegas, NV

Chemical Interactions is the UNLV ACS student affiliate chapter. We engage in various events and activities that raise awareness of the importance of chemistry through outreach to local students of all ages. We do this by taking part in ACS events such as National Chemistry Week and Earth Day. We also participate in community service, as this provides an outlet for club members to give back to the community. We provide our club members with exposure to real world chemistry by taking tours of relevant facilities with chemists on staff. At the same time these tours give information about possible jobs, internships, and how to get started in the chemistry field. Overall the club offers our members with many opportunities to become involved with the university and community through chemistry.

Computational Studies of H2, O2, and CO Adsorption on Pt and Pt-Ru Catalyst Clusters for Hydrogen Fuel Cell Applications
Huy Mai, T. J. Dhilip Kumar, P. Tarakeshwar and N. Balakrishnan, University of Nevada Las Vegas, Las Vegas, NV

We present density functional theory calculations of chemisorption of H2, O2, and CO molecules on pure platinum (Pt4) and platinum-ruthenium clusters (Pt3Ru) of tetrahedral and rhombus configurations. Unlike most previous computational studies of hydrogen fuel cell catalysis in which the interaction of a single adsorbate molecule with the catalyst cluster was investigated, we explore the effect of co-adsorbed molecules on the catalytic activity. Adsorption energy, HOMO-LUMO energy gap, and electrostatic potential map of each metal-adsorbate system were calculated to investigate the effect of adsorbate saturation on the catalyst particle. Results show that the doping of Ru into tetrahedral Pt structure raises the adsorption energy initially for hydrogen and oxygen interactions. However, Ru doping causes a decrease in the adsorption energy after four adsorbates while that of pure Pt remains nearly constant during the adsorption process. For CO adsorption, the doping of Ru lowers the adsorption energy for all four CO molecules interacting with the cluster. This shows that Ru-doped clusters may be less susceptible to CO poisoning because the adsorbed CO molecules can be easily desorbed at lower temperatures.

Experimental Investigation of Nondipole Effects in X-Ray Photoemission
Kyle P. Bowen, Oliver Hemmers and Dennis W. Lindle, University of Nevada Las Vegas, Las Vegas, NV

The dipole approximation, which yields simple and straightforward rules for the interactions between light and matter, is the simplest possible assumption governing such interactions. Until recently, it was thought to be the correct depiction of photoionization processes in atoms and molecules for low photon energies (hν<1keV). However, breakdowns in the dipole approximation are now being investigated. Angular distribution measurements of photoelectrons show that nondipole effects are significant even for energies on the order of a few tens of eV, such as seen in Xe, and can have considerable magnitudes, as in the case of N2.

Best Practices and Best Activities in Tertiary Chemistry I

Organizer: MaryKay Orgill University of Nevada, Las Vegas, Las Vegas, NV

Best Practices and Best Activities in Tertiary Chemistry II

Organizer: MaryKay Orgill University of Nevada, Las Vegas, Las Vegas, NV Presider: MaryKay Orgill University of Nevada, Las Vegas, Las Vegas, NV

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UNLV, State System of Higher Education Receives $ 15 Million to Study Climate Change in Nevada

NATIONAL SCIENCE FOUNDATION GRANT TO FOR RESEARCH, EDUCATION AND OUTREACH ON CLIMATE CHANGE EFFECTS

The College of Sciences will participate with NSHE and UNLV colleagues in the implementation of a five year grant from the National Science Foundation (NSF) through Nevada EPSCoR (Experimental Program to Stimulate Competitive Research).

Researchers from UNLV and partner Nevada System of Higher Education institutions recently received $15 million from the National Science Foundation (NSF) to investigate climate change and its effects on Nevada.

The five year effort will team nearly 20 UNLV faculty members with researchers from UNR, Desert Research Institute and Nevada State College to develop the infrastructure necessary to determine how climate impacts the state’s ecosystem services, specifically water resources. Faculty and students also plan to work with community leaders to direct research efforts that will inform policy and decision-making across the state.

“Climate change and its associated impacts to resources, economics, and society are among the most important issues facing the region, nation and world,” said Thomas Piechota, co-principal investigator and UNLV director of sustainability and multidisciplinary research. “This project will not only improve our understanding climate change impacts to our ecosystems and water resources, but will also focus on solutions to scientific and social issues that lead to informed decision making.”

An interdisciplinary team of faculty from each institution will focus their efforts on six interrelated components– climate modeling, ecology, water resources, policy and outreach, education and cyberinfrastructure. UNLV will participate in all of these areas with a focus in water resources, policy and education.

Project highlights include the development of an ecological monitoring network designed to measure the basic parameters of climate change necessary to determine the potential impact of climate change on the state’s water resources and biodiversity. The network of stations will contribute to research in the areas of ground water recharge, wildland fires and invasive and endemic species.

In addition, UNLV will house a three-dimensional visualization facility in the new Science and Engineering Building that will make interactive, real-time data accessible to researchers, students, decision makers and the public. The “Solutions Room” will serve as a hub for researchers and community leaders to interpret and discuss climate-related issues in an IMAX-like setting.

Aside from infrastructure, the grant will fund three new faculty positions, graduate student assistantships, undergraduate fellows, and postdoctoral fellows. Also, more than $1 million will fund interdisciplinary research teams from multiple institutions that will take advantage of the infrastructure developed through the grant.

Grant funding from the NSF will be distributed equally among partner institutions, with UNLV to receive approximately $4.5 million. As part of NSF requirements that states show commitment to the project, the Nevada System of Higher Education will provide $6.5 million in total funding to the project from non-federal sources.

The grant was funded by the NSF through Nevada EPSCoR (Experimental Program to Stimulate Competitive Research), which began in Nevada in 1985 to strengthen research and education in science and engineering and to provide strategic programs and opportunities that stimulate sustainable improvements in research and infrastructure in states that are historically underfunded by federal agencies.

For a complete description of the grant and continuous updates, please visit the Nevada EPSCoR web site at www.nevada.edu/epscor.

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Staying Alive: Despite a Three-Decade Decline, Few Universities Keep Nuclear and Radiochemistry Going

“Staying Alive: Despite a Three-Decade Decline, Few Universities Keep Nuclear and Radiochemistry Going,” Chemical And Engineering News, by Linda Raber, September 8, 2008. Volume 86, Number 36, pp. 68-70.

This article discusses the challenges facing the fields of nuclear and radiochemistry, and identifies UNLV as a growing influence in this important arena.

Full Text: http://pubs.acs.org/cen/education/86/8636education4.html

CONSIDERING THEIR SMALL subdiscipline ranking among the chemical sciences, nuclear and radiochemistry have always made outsized contributions. Nevertheless, a steady 30-year decline has left annual Ph.D. production in the U.S. in these fields to fewer than 10 Ph.D.s. Because so few retirees are being replaced with faculty in the same area, the survival of the fields is in the hands of a dedicated cadre of faculty at a half dozen or so universities.

In medicine alone, nuclear and radiochemists have helped to revolutionize imaging, pharmaceuticals, and cancer treatment (see page 13). These same scientists have unlocked the mysteries of the solar neutrino and given the world carbon dating and numerous other analytical techniques. Nuclear chemists have expanded the periodic table of the elements, identifying plutonium and subsequently all the transuranium elements.

Strictly speaking, radiochemistry is the study of radioactive elements using chemical techniques, whereas nuclear chemistry is the study of the fundamental properties of atomic nuclei using chemical techniques. These days, however, the terms are used almost interchangeably…

…THE NUMBER of people pursuing advanced education in nuclear and radiochemistry is tiny, despite the great need. This is not surprising, given that the most recently launched nuclear power plant in the U.S. started operations more than 30 years ago, though recent talk about a resurgence in nuclear power could turn the tables. The present shortfall might also stem from public relations and outreach problems because so many people seem to be turned off by the terms "nuclear" and "radioactive."

Shrinkage of the ranks is exacerbated when nuclear chemistry faculty who retire are replaced with chemistry faculty in other disciplines, areas such as nanotechnology and materials science, that are seen as less mature. In addition, nuclear and radiochemistry are considered expendable in the current chemistry curriculum, even the curriculum mandated for an American Chemical Society-approved bachelor's degree…

…An analysis of the 2007 online edition of the "ACS Directory of Graduate Research," the most recent one available, shows that only 22 universities in the U.S. offer nuclear chemistry education at any level. Excluding emeritus and retired faculty, there are currently 39 faculty in nuclear chemistry in the U.S. Many of these educators, on whom the future of the field depends, are near or past retirement age. They are on average more than 60 years of age—10 years older than their peers in other chemical sciences areas.

Darleane C. Hoffman, professor of nuclear chemistry at the University of California, Berkeley, says her university has graduated 19 Ph.D.s in nuclear chemistry in the past 10 years. She believes that the annual production of two Ph.D.s will hold steady in the foreseeable future. "Although relatively healthy now, I would call our program fragile. We need to hire a new professor as soon as possible, as we have two out of our three faculty at retirement age," she says.

Hoffman believes the "crisis situation is beginning to turn around" and a few universities have appointed new professors with expertise in nuclear and radiochemistry. One such program is at the University of Nevada, Las Vegas. Ken Czerwinski, director of the radiochemistry program that he started there in 2004, tells C&EN that the program just graduated its first Ph.D. The program has three faculty and about 20 students.

Within the next several years, Czerwinski believes six to 10 students will get their degrees. The program at UNLV is substantially funded through Sen. Harry Reid's (D-Nev.) 2003 earmark aimed at the study of the treatment and reprocessing of spent nuclear fuel. Czerwinski says the faculty in his program work with those in other areas, particularly inorganic chemistry, synthetic chemistry, electrochemistry, and detection. "We also develop programs with national laboratories," he says…

Courtesy of Moses Lee Rare researcher Nicholas Smith, a graduate student at UNLV, uses ultraviolet-visible spectroscopy to monitor concentrations and determine speciation in the advanced fuel cycle.

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From Mothballs to Mobilization: Taking the Salt Out of Sea Water

Geoscience faculty members will participate in the Joint Annual Meeting of five science societies: Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies, and the Houston Geological Society, from October 5-9, 2008 in Houston, Texas. This unprecedented joint technical program will feature papers from all geological disciplines and the soil, agronomic, and crop sciences. Among the presentations highlighted is one from UNLV geoscience professor David Kreamer. A Geological Society of America press release describes his talk.

Press release:

The United Nations estimates that 1.1 billion people across the globe lack access to sustainable, clean drinking water and that 1.6 million children will die each year because of that lack of access. How can science help provide more drinkable water for a growing population on an Earth with limited fresh surface-water and groundwater resources?

Geoscientist David Kreamer of the University of Nevada, Las Vegas, noting that at least 37% of the world's population lives within 100 kilometers of a coastline, says that desalinization -- removing salt from ocean water to create fresh water -- is a practical way to meet the growing human need.

Desalinization is not a novel idea, says Kreamer. U.S. Navy aircraft carriers, for example, have had to generate fresh water to help sustain large crews while at sea for six months or more.

In fact, says Kreamer, such ships are ideal platforms for desalinization. And what better use for large, mothballed ocean vessels currently dry-docked or cluttering working harbors? The U.S. alone has a fairly large mothball fleet, including U.S. Navy inactive ships and the U.S. Merchant Marine reserve fleet. Kreamer's work examines the practicality of recycling decommissioned U.S. Navy vessels, especially with an eye toward using old aircraft carriers, to become mobile desalinization plants.

When ships meet the end of their service life with the U.S. Navy, they are often quite serviceable. Kreamer notes that the decommissioning of the John F. Kennedy multipurpose aircraft carrier in August 2007 saved the Navy about 1.2 billion U.S. dollars, yet the vessel itself is still sea worthy and could be a good candidate for work as a desalinization plant. A change in purpose would save money in other areas as well. The John F. Kennedy aircraft carrier had a crew of about 5,200, but says Kreamer, "You wouldn't have as many people working a desalinization plant."

In his talk on 5 October at the 2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, and Gulf Coast Association of Geological Societies, in Houston, Texas, USA, Kreamer will take a practical view of the advantages and disadvantages of using formerly mothballed ships to serve as mobile desalinization plants across the globe.

Kreamer will also address how voyaging desalinization plans can (1) help reach more people in need – "they could outrun a hurricane and steam within days to an area of natural or man-made disaster"; (2) harness wind, wave, and solar power to help sustain operations; and (3) meet cost, center of gravity, and environmental concerns.

The Discovery Channel also reported on this presentation:
http://dsc.discovery.com/news/2008/10/06/ship-desalination.html

Science News also reported on this presentation:
http://www.sciencedaily.com/releases/2008/09/080930135307.htm

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How Bees Wing It

Associate professor Stephen Roberts, school of life sciences, is a member of the research team that is studying the aerodynamics of honeybees in order to design “micro aerial vehicles.” A recent National Geographic article (“How Bees Wing It,” Jennifer S. Holland, National Geographic, August, 2008, Vol. 214, No. 2, p. 30), includes data and illustrations on the flight mechanics of honeybees and includes data.

The scholarly article that serves as the basis for this information is:

“Short-amplitude high-frequency wing strokes determine the aerodynamics of honeybee flight,” Altshuler D.L., Dickson W.B., Vance J.T., Roberts S.P., and Dickinson M.H. Proceedings of the National Academy of Sciences (PNAS). 2005 Dec 13;102(50):18213-8.

Abstract: Most insects are thought to fly by creating a leading-edge vortex that remains attached to the wing as it translates through a stroke. In the species examined so far, stroke amplitude is large, and most of the aerodynamic force is produced halfway through a stroke when translation velocities are highest. Here we demonstrate that honeybees use an alternative strategy, hovering with relatively low stroke amplitude (approximately 90 degrees) and high wingbeat frequency (approximately 230 Hz). When measured on a dynamically scaled robot, the kinematics of honeybee wings generate prominent force peaks during the beginning, middle, and end of each stroke, indicating the importance of additional unsteady mechanisms at stroke reversal. When challenged to fly in low-density heliox, bees responded by maintaining nearly constant wingbeat frequency while increasing stroke amplitude by nearly 50%. We examined the aerodynamic consequences of this change in wing motion by using artificial kinematic patterns in which amplitude was systematically increased in 5 degrees increments. To separate the aerodynamic effects of stroke velocity from those due to amplitude, we performed this analysis under both constant frequency and constant velocity conditions. The results indicate that unsteady forces during stroke reversal make a large contribution to net upward force during hovering but play a diminished role as the animal increases stroke amplitude and flight power. We suggest that the peculiar kinematics of bees may reflect either a specialization for increasing load capacity or a physiological limitation of their flight muscles.

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Alpha Epsilon Delta (AED) – Nevada Beta Chapter

This student organization coordinates such student activities as: the Physician Shadowing Program; Dentist Shadowing Program; Humanitarian Service Program; Bone Marrow Donor Registration Drive; Organ Donor Registration Drive; annual presentations from nationally ranked medical schools (Duke University School of Medicine, Washington University in St. Louis School of Medicine, etc,); annual presentations from pharmacy programs (Creighton University School of Pharmacy and Health Sciences, etc.); the annual tour of the UNLV School of Dental Medicine; and various community service activities.

In recent weeks the Alpha Epsilon Delta (AED) – Nevada Beta Chapter members assisted the Polycystic Kidney Disease (PKD) Foundation by volunteering for a fundraising walk at Acacia Park in Henderson on Saturday, September 20, 2008. The PKD Foundation is the only organization, worldwide, dedicated to promoting research to find a cure for polycystic kidney disease (PKD) and improving the care and treatment of those it affects. In 2007, the PKD Foundation funded more than $4.2 million in vital PKD research. Polycystic kidney disease (PKD) is a genetic disorder characterized by the growth of numerous cysts in the kidneys. When cysts form in the kidneys, they are filled with fluid. PKD cysts can profoundly enlarge the kidneys while replacing much of the normal structure, resulting in reduced kidney function and leading to kidney failure. Area PKD Foundation chapters raise funds to support research by organizing charity events including but not limited to Walk for PKD. In these events, walkers secure sponsorship from individuals and corporations ranging from $100 - $1,000 for completion of a 2.5 kilometer walk. Approximately thirty Alpha Epsilon Delta members provided support for this event by setting up concessions, related activities, and awards tables. AED also assisted with disassembly of all equipment and cleaning of the park area following the completion of the event. This event raised approximately $11,427.00 for the PKD foundation.

AED members are also involved in environmental activities. Approximately thirty members participated in the Fall “Green Up” event at the Las Vegas Wash, adjacent to Sam Boyd Stadium on Saturday, September 27, 2008. In this endeavor, AED members helped to plant more than 2,000 trees in the wash to prevent soil erosion and slow the progress of invasive species such as the Salt Cedar tree. AED participates in this event twice annually, each Fall and Spring season.

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Powerpoint Presentations

The two powerpoint presentations have been added to the COS website, under the heading "Other Publications," on the Publications webpage:

URL: http://sciences.unlv.edu/publications.html

College of Sciences Clark County School District Presentation, 2008 (Power Point)
http://sciences.unlv.edu/pdf/CCSD-Meeting-082108%20.ppt

A presentation of information and data on the College of Sciences for Clark County School District science teachers,

College of Sciences Pre-Professional Program, 2007-2008 (PDF)
http://sciences.unlv.edu/pdf/Counselor-to-College-Presentation.pdf

A presentation on the Pre-professional Advising Program for Clark County School District advisors and teachers,

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David L. Weide Memorial Lecture

The inaugural David L. Weide Memorial Lecture will be held at the University of Nevada Las Vegas (UNLV), Lilly Fong Geosciences Building, Room 102, on November 19, 2008, at 4:00 p.m.

The inaugural lecture will be presented by Dr. Vic. Baker, University of Arizona and is entitled, "Megafloods on Earth and Mars."

A Remembrance Reception will follow the lecture.

The UNLV Department of Geoscience established a lecture series to commemorate Dr. David L. Weide, who was a faculty member from 1973 to 2004. Dave's leadership, knowledge, commitment, and unique style of spirited enthusiasm helped to create an internationally recognized department. His research interests included urban geologic hazards, including flood hazards, unstable soils, tectonic-seismic hazards, and mass movement. He authored many peer-reviewed scholarly articles, government and consulting reports, and more than 25 geologic maps.

Dr. Weide mentored graduate students and taught over 15 different courses in geology, geography, and geomorphology. He was renowned for his teaching style in introductory classes where he engaged more than 5,000 students in learning. He was a Fellow of the Geological Society of America, and a member of Phi Kappa Phi, American Quaternary Association, and Society for Archaeological Sciences. He also served as a geologist with the U.S. Geological Survey, as Senior Museum Scientist at UCLA Department of Geology, as a geologist with the University of California Archaeological Survey Office, and with the National Science Foundation European Projects. Weide earned his B.S. degree in geology from California State University, Los Angeles, and M.S. and Ph.D. degrees from the University of California, Los Angeles in 1974.

The David L. Weide Memorial Lecture Series is supported by the David L. Weide Memorial Fund. Tribute gifts are welcomed at http://geoscience.unlv.edu.

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DIAMOND 2008 Conference

Michael Pravica, associate professor of physics and astronomy presented a contributed talk at the DIAMOND 2008 conference in Sitges, Spain on Tuesday, September 9. The title of Professor Pravica's talk was, "A novel method to dope diamond - ion beam nuclear transmutation doping (IBNTD)." A paper based upon this presentation is currently under peer review. Diamond 2008, in the 19th annual European Conference on diamonds, diamond-like materials, carbon nanotubes, and nitrides. The conference covers all aspects of vapour growth diamond, natural and synthetic diamond, nano-diamond, and related materials such as carbon nanotubes, diamond-like carbon and wide gap nitrides particularly cubic boron nitride.

The Department of Chemistry and the School of Life Sciences hosted a presentation by professor Tom Leyh, Albert Einstein College of Medicine. On Friday September 19, 2008. Professor Leyh, an expert in enzymology, offered a seminar entitled “"Channeling in Sulfur Metabolism and Drug Development in Isoprenoid Biosynthesis."

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CHEMISTRY COLLOQUIUM

At 2:00 p.m. pm September 20, 2008 in Marjorie Barrick Auditorium, Professor Chien Wai, Department of Chemistry, University of Idaho will present a talk entitled, “Environmentally-Sustainable Processes for Nuclear Waste Management.”

Abstract: Current research status of using supercritical fluid carbon dioxide and room temperature ionic liquids as solvents for dissolution, extraction, and separation of lanthanides and actinides is discussed. An industrial demonstration of the supercritical fluid extraction technology for recovering enriched uranium from incineration ash produced by a nuclear fuel fabrication plant is presented.

Professor Wai is leading the research efforts on environmentally sustainable supercritical fluid extraction and ionic liquids. Over the course of 20 years, he has developed a process that uses supercritical fluids to dissolve toxic metals. When coupled with a purifying process developed in partnership with Sydney Koegler, an engineer with nuclear industry leader AREVA and University of Idaho alumnus, enriched uranium can be recovered from the ashes of contaminated materials.

For more information, please contact: Patricia Paviet-Hartmann, Harry Reid Center for Environmental Studies, 5-5488, Patricia.Paviet-Hartmann@unlv.edu.

 

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On Friday, September 19th, Dr. Nick Schurch from the Institute for High Energy Physics at the Chinese Academy of Sciences presented a talk entitled, “Where are the accretion disk winds in AGN?"

Abstract: Hydrodynamic simulations of accretion disks in active galaxies ubiquitously predict the presence of mass-outflows originating from the accretion flow. Strong evidence for the existence of these outflows comes from the blue-shifted, highly ionized, absorption lines detected in the optical/ultra-violet/X-ray spectra of broad absorption line quasi-stellar objects, however other properties of these outflows are conspicuous by their absence (notable exceptions are the few instances of high ionization iron absorption lines observed in some nearby quasars). I will describe the recent development of the numerical code XSCORT, which simulates UV/X-ray spectra of AGN observed through ionized outflowing material. This code allows us to predict and investigate the detailed characteristic spectral features imprinted on the UV/X-ray spectra by an accretion disk wind. We couple this code with the best available hydrodynamic simulations of accretion disk winds in a quasar to enable us to explore the X-ray spectral features produced by a realistic, self-consistent, line driven accretion disk wind. The resulting spectra represent the most realistic picture to date of the direct AGN X-ray continuum seen through an accelerating accretion disk wind, are strongly dependent on viewing angle, and are strongly time variable. The simulated spectra do not reproduce the smooth soft X-ray excess, instead showing considerable, sharp, atomic features imprinted across the spectrum. While the higher inclination angles are dominated by Compton scattering and nearly neutral absorption, spectra from smaller inclination angles show highly-ionized, blue-shifted, Fe absorption features in the 6.7-9 keV range that are qualitatively similar to features observed in the X-ray spectra of a growing number of AGN. Finally I will give an overview of my recent work developing a code that will allow the model spectra to be compared quantitatively to the X-ray observations. When compared to a large sample of AGN that all show features thought to be associated with accretion disk winds, this work will (hopefully) illuminate the importance of including accretion disk outflows in the unified AGN schemes.

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School of Life Sciences Seminar

On Friday October 30, 2008, Dr. James L. Patton, Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley will offer the School of Life Sciences weekly seminar. His talk is entitled, “Predicting the Future From the Record of the Past,” and will be presented in White Hall Auditorium at 3:30 p.m. Jim Patton is widely regarded as one of the most influential evolutionary biologists of his generation. He has received several research and teaching awards, as well as the highest distinction bestowed by the UC Berkeley campus on a faculty member. Jim and his colleagues documented how climate change has significantly affected the distribution, abundance, and community structure of small mammals in Yosemite National Park, California. The article reporting these findings will be published in the prestigious journal Science in a few weeks, and is poised to attract considerable attention from the popular press. Jim is an engaging public speaker, and his talk is aimed at a general audience. Individuals interested in the effects of global climate change on biotic communities may be interested in attending Jim's seminar.

 

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Mathematics Colloquium

On Friday, October 10, 2008 at 12”00 p.m., Dr. Lurdes Inoue, Department of Biostatistics, University of Washington, Seattle for will present a Statistics Seminar entitled, “Modeling Disease Progression," in CBC C-224.

Abstract: In this talk I discuss some modeling approaches to investigate disease progression. First, we propose a model that links longitudinal biomarker and disease progression. Specifically, we consider an underlying latent disease process that describes the onset of the disease and models the transition to an advanced stage of the disease as dependent on the biomarker levels. Next, we propose a variation of the above model to investigate disease progression using data prospectively collected in a screening study. We illustrate our methods through simulations and a case study in prostate cancer.

On Friday October 10, 2008, Dr. Clifford Hansen, Sandia National Laboratories, will present a talk on behalf of the Center for Applied Mathematics and Statistics. (http://www.unlv.edu/centers/cams/index.html). Individuals interested in the current performance assessment of the Yucca Mountain Repository may be interested in attending this talk, entitled, “Performance Assessment for the Proposed Yucca Mountain Repository,” at 10:30 a.m.-11:30 a.m., in CBC-C230.

Abstract: The conceptual structure of the performance assessment for the proposed high-level radioactive waste repository at Yucca Mountain, Nevada, is described. The performance assessment was carried out to support the recently-submitted license application by the U.S. Department of Energy (DOE) to the U.S. Nuclear Regulatory Commission (NRC). Mathematically, the performance assessment involves three entities: (1) a probabilistic characterization of the uncertainty in the occurrence of future events that could affect the performance of the repository; (2) a linked system of models for predicting the physical behavior and evolution of the repository; and (3) a probabilistic characterization of the uncertainty associated with analysis inputs that results in a range of uncertainty on analysis output. The presentation summarizes how the performance assessment is organized to address the regulations for the proposed repository and the overall results of the assessment. In addition, this presentation uses results from the performance assessment to illustrate the use of sensitivity analysis techniques to develop insight and understanding into a complex analysis. Finally, the presentation indicates the role of the mathematical sciences in the performance assessment.

On Friday, October 3, 2008 Dr. Benjamin Kedem, University of Maryland will present a talk, “Bayesian Spatial Prediction,” in CBC-C224 at 11:30 a.m.

Abstract: I will discuss Bayesian spatial/temporal prediction in transformed Gaussian random fields where the transformation belongs to a parametric family. Monte Carlo integration is used in the approximation of the predictive density function, which is easy to implement in this framework. The BTG software for the implementation of the method will be discussed by means of spatial and temporal examples. As a byproduct, we provide a Bayesian way to tackle the distribution problem of average rainfall rate.

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