Chemistry Commons^™

Loading Microcolumns For The Separation Of Analytes From A Sample In The Millisecond Time Scale, David S. Hage, William A. Clarke

David Hage Publications

The present invention generally relates to a microcolumn capable of separating an analyte from a sample in the millisecond time domain. The microcolumn is capable of such rapid separation by employing small column volumes that can tolerate medium to high flow rates. The invention also relates to a method of loading a microcolumn capable of separating an analyte from a sample in the millisecond time domain using plural injections of the packing material.

Clear-Column Radiative Closure During Ace-Asia: Comparison Of Multiwavelength Extinction Derived From Particle Size And Composition With Results From Sun Photometry, J. Wang, Richard C. Flagan, John H. Seinfeld, Haflidi Jonsson, D. R. Collins, P. B. Russell, Beat Schmid, Jens Redemann, J. M. Livingston, Song Gao, Dean A. Hegg, E. J. Welton

Chemistry and Physics Faculty Articles

From March to May 2001, aerosol size distributions and chemical compositions were measured using differential mobility analyzers (DMA), an aerodynamic particle sizer (APS), Micro-Orifice Uniform Deposit Impactors (MOUDI), and denuder samplers onboard the Twin Otter aircraft as part of the Aerosol Characterization Experiment (ACE)-Asia campaign. Of the 19 research flights, measurements on four flights that represented different aerosol characteristics are analyzed in detail. Clear-column radiative closure is studied by comparing aerosol extinctions predicted using in situ aerosol size distribution and chemical composition measurements to those derived from the 14-wavelength NASA Ames Airborne Tracking Sun photometer (AATS-14). In the boundary layer, …

Osaka University: A Focus Of Polymer Science: 70th Anniversary Celebration, Otto Vogl, Koichi Hatada

Emeritus Faculty Author Gallery

No abstract provided.

Personalities In Polymer Science: Cover Page, Title Page, Introduction, And List Of Articles, Otto Vogl

Emeritus Faculty Author Gallery

A compilation of articles with short biographies of the scientists who played leading roles in the field and provided the basis of Polymer Science and Technology throughout the 20th century.

Poly(Meta-Phenylene Isophthalamide) Nanofibers: Coating And Post Processing, Wenxia Liu, Matthew Graham, Edward A. Evans, Darrell H. Reneker

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Electrospun nanofibers have applications in the areas of filtration, composites; biomaterials, and electronics. Controlling the surface properties of these nanofibers is important for many applications. Nanofibers can also be used as unique substrates for observing the growth of deposited films and creating nanoscale structures. In this work, electrospun poly(meta-phenylene isophthalamide) (MPD-I) nanofibers were used as substrates for creating nanoscale structures out of carbon-based materials and metals. MPD-I was used because it can be electrospun into nanofibers with diameters smaller than 10 nm and it has good thermal stability. MPD-I nanofibers were coated with carbon, copper, and aluminum using plasma enhanced …

Immobilization Of Fission Iodine By Reaction With A Fullerene Containing Carbon Compound And Insoluble Natural Organic Matrix: Quarterly Report September-December 2002, Spencer M. Steinberg

Separations Campaign (TRP)

The recovery of iodine released during the processing of used nuclear fuel poses a significant challenge to the transmutation of radioactive iodine. This proposal will develop and examine the use of Fullerene Containing Carbon (FCC) compounds as potential sorbents for iodine release from the reprocessing of nuclear fuel. This work will also include the development of bench-scale testing capabilities at UNLV to allow the testing of the FCC material in a simulated process off-gas environment. This experimental capability will also be used to test other potential sorbtion materials and processes, such as natural organic matter (NOM) and other promising alternatives. …

An Examination Of Predatory Pressures On Piping Plovers Nesting At Breezy Point, New York, Brook Lauro, John Tanacredi Ph.D.

Faculty Works: CERCOM

This study examines predatory threats to Piping Plovers (Charadrius melodus) nesting at Breezy Point, Gateway National Recreation Area, New York. Several methods used include: 1) an evaluation of reproductive success data with documentation of predation to eggs and chicks, 2) predator surveys, and 3) an artificial nest study. The range of breeding pairs nesting from 1988-1996 was 11-19, with an average of 15.8 (SE ± 0.79) pairs/season. The average number of eggs hatched and chicks fledged per year for pairs was 2.2 ± 0.23 and 0.8 ± 0.16 respectively. Reasons for egg losses often went undetected (68%) but …

Directed Ortho-Metalation Of Dimethylarylamines, Michael Timmons

Masters Theses & Specialist Projects

Site-specific product(s) from the reaction of benzene derivatives with various reagents is a need of researchers at numerous laboratories, particularly those in the pharmaceutical industry. Such derivatives can be synthesized directly, i.e., by substitution of a proton, using either of two procedures: electrophilic aromatic substitution (EAS) or directed ortho-metalation (DoM). Directed ortho-metalation (DoM) is an alternative aromatic substitution process initiated by organolithium reagents which provides regiospecific substitution exclusively at the ortho- position (equation). The focus of this study is to find hydrocarbon media that will permit the maximum extent of metalation of several dimethylarylamines. The dimethylamine-containing substituents constitute directing metalation …

Electronic Structure Of Thallium Filled Skutterudites Studied By X-Ray Absorption And Mössbauer Spectroscopy, Gary J. Long, Bernard M. Mahieu, Brian C. Sales, Raphäel P. Hermann, Fernande Grandjean

Chemistry Faculty Research & Creative Works

The electronic structure of the three sites in the thallium filled skutterudites was studied. Two series of thallium filled skutterudites were formed because thallium has a formal valence of +1 and iron or tin must replace some of the cobalt or antimony respectively, to maintain charge neutrality. Large atomic mean-square displacements were observed for the thallium filling atoms and it helps to produce the large thermal resistivity observed for these skutterudites.

Superfluidity In The Solar Interior: Implications For Solar Eruptions And Climate, Oliver Manuel, Barry W. Ninham, Stig Friberg

Chemistry Faculty Research & Creative Works

Efforts to understand unusual weather or abrupt changes in climate have been plagued by deficiencies of the standard solar model (SSM) [1]. Although it assumes that our primary source of energy began as a homogeneous ball of hydrogen (H) with a steady, well-behaved H-fusion reactor at its core, observations instead reveal a very heterogeneous, dynamic Sun. As examples, the upward acceleration and departure of H⁺ ions from the surface of the quiet Sun and abrupt climatic changes, including geomagnetic reversals and periodic magnetic storms that eject material from the solar surface are not explained by the SSM. The present …

Monte Carlo Simulation Of Vapor–Liquid Binodal Of Water, S. Yoo, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Among many popular potential models of water, the nonpolarizable four-site TIP4P potential is one of the more widely used. Recently, two new potential models of water on the basis of the TIP4P potential have been developed. One is the four-site Dang–Chang polarizable potential and another is the five-site TIP5P potential. The former is designed to describe not only bulk and interfacial properties of liquid water but also microclusters of water. The nonpolarizable TIP5P potential is the latest version in the TIP series from the Jorgensen group. Compared with the TIP4P potential, for example, the TIP5P potential gives a much improved …

Synthesis Of A Spacer-Armed Disulfated Tetrasaccharide Of Sb1a, A Carbohydrate Hapten Associated With Human Hepatocellular Carcinoma, Qin Li, Hui Li, Qing Li, Qing Hua Lou, Bin Su, Meng Shen Cai, Zhong Jun Li

Chemistry Faculty Publications

A disulfated tetrasaccharide fragment with a spacer arm of human hepatocellular carcinoma carbohydrate antigen SB1a, namely, 2-aminoethyl 3-O-sulfo-β-d-galactopyranosyl-(1→3)-2-acetamido-2-deoxy-β-d-galactopyranosyl-(1→4)-3-O-sulfo-β-d-galactopyranosyl-(1→4)-β-d-glucopyranoside was synthesized via a [2+1+1] block building mode. In the last coupling step toward the trisaccharide acceptor 8, benzoyl protected galactosyl bromide donor 14 was found to be much more reactive than the acetyl-protected donors. A disulfated tetrasaccharide fragment with a spacer arm of human hepatocellular carcinoma carbohydrate antigen SB1a was synthesized via a [2+1+1] block building mode.

Seasonality Of Dissolved Rare Earth Elements In The Lower Mississippi River, Alan M. Shiller

Faculty Publications

[1] Dissolved rare earth element (REE) concentrations were determined in a 27-month time series of the lower Mississippi River. Overall, the results agree with limited previous investigations; that is, the river shows enrichment of heavy REEs relative to light REEs and also has a significant Ce anomaly. However, the previous investigations relied on only single samples from the river. This seasonal investigation reveals significant temporal variations in the river's REE chemistry. In particular, large ( approximately fivefold) variations in light REE concentrations are observed. The light REEs follow a seasonality similar to particle-reactive trace elements. Also, the Ce anomaly shows …

Development Of A Systems Engineering Model Of The Chemical Separations Process: Quarterly Progress Report 8/16/02- 11/15/02, Yitung Chen, Randy Clarksean, Darrell Pepper

Separations Campaign (TRP)

Two activities are proposed in this Phase I task: the development of a systems engineering model and the refinement of the Argonne code AMUSE (Argonne Model for Universal Solvent Extraction). The detailed systems engineering model is the start of an integrated approach to the analysis of the materials separations associated with the AAA Program. A second portion of the project is to streamline and improve an integral part of the overall systems model, which is the software package AMUSE. AMUSE analyzes the UREX process and other related solvent extraction processes and defines many of the process streams that are integral …

1. Yukio Imanishi, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.

Corrosion Of Steel By Lead Bismuth Eutectic: Quarterly Report August September October 2002, John Farley

Transmutation Sciences Materials (TRP)

We continued with sputter depth profiling of 316 and 316L steel samples that have been exposed to LBE. We also calibrated the sputter depth profiling using a sample of SiO₂ on Si, and the SEM. This is a valuable independent determination of the thickness of oxide layers.

In the laboratory, progress continues using the XPS machine. Experiments have been performed on steel samples using Argon ions to mill away the surface of the sample, thereby making measurements as a function of depth. This "ion beam milling" proceeds slowly through the oxide layer that covers the steel sample. We are …

Calcium Binding To Calmodulin Mutants Monitored By Domain-Specific Intrinsic Phenylalanine And Tyrosine Fluorescence, W. S. Vanscyoc, B. R. Sorensen, E. Rusinova, William Laws, J. B. A. Ross, M. A. Shea

Chemistry and Biochemistry Faculty Publications

Cooperative calcium binding to the two homologous domains of calmodulin (CaM) induces conformational changes that regulate its association with and activation of numerous cellular target proteins. Calcium binding to the pair of high-affinity sites (III and IV in the C-domain) can be monitored by observing calcium-dependent changes in intrinsic tyrosine fluorescence intensity (lambda(ex)/lambda(em) of 277/320 nm). However, calcium binding to the low-affinity sites (I and II in the N-domain) is more difficult to measure with optical spectroscopy because that domain of CaM does not contain tryptophan or tyrosine. We recently demonstrated that calcium-dependent changes in intrinsic phenylalanine fluorescence (lambdaex/lambdaem of …

Fragmentation Processes Following Core Excitation In Acetylene And Ethylene By Partial Ion Yield Spectroscopy, Maria Novella Piancastelli, Wayne C. Stolte, Gunnar Ohrwall, S-W Yu, D. Bull, K. Lantz, Alfred S. Schlachter, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

Partial ion yield spectroscopy provides a very detailed picture of fragmentation processes following core excitation in isolated molecules. We exploit this potential in the analysis of decay processes following C1s→π and C1s→Rydberg excitations in ethylene and acetylene. We show that the relative intensity of spectral features related to the excitation to empty molecular orbitals or to Rydberg states is a function of the time variation of the fragmentation process. Namely, we see an intensity increase in the Rydberg states compared to the molecular orbitals as the fragmentation process becomes more extensive, a result attributable to the diffuse nature of the …

Effect Of An Electric Field On The Surface Tension Of A Dipolar-Quadrupolar Fluid And Its Implication For Sign Preference In Droplet Nucleation, V.B. Warshavsky, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The effect of a uniform electric field on interfacial properties of dipolar-quadrupolar fluids is investigated by using the density-functional theory. As in the case of purely dipolar fluids the (thermodynamic) surface tension is always altered by the external field, regardless of the direction of the field. However, unlike the purely dipolar fluids, for two given external fields with the same strength but exactly opposite direction the magnitude of variation in the surface tension is different. This apparent symmetry breaking by reversing the field direction suggests a new molecular mechanism to explain the phenomenon of sign preference in droplet formation on …

Distributions Of Nobel Metal Pd And Pt In Mesoporous Silica, J. Arbiol, A. Cabot, J. R. Morante, Fanglin Chen, Meilin Liu

Faculty Publications

Mesoporous silicananostructures have been synthesized and loaded with Pd and Pt catalytic noble metals. It is found that Pd forms small nanoclusters (3–5 nm) on the surface of the mesoporous structure whereas Pt impregnation results in the inclusion of Pt nanostructures within the silica hexagonal pores (from nanoclusters to nanowires). It is observed that these materials have high catalyticproperties for CO–CH₄CO–CH₄CO–CH₄ combustion, even in a thick film form. In particular, results indicate that the Pt and Pd dispersed in mesoporous silica are catalytically active as a selective filter for gas sensors.

Rapid Determination Of Serum Melatonin By Esi–Ms–Ms With Direct Sample Injection, Shuming Yang, Xiaohui Zheng, Yan Xu, Xiang Zhou

Chemistry Faculty Publications

This paper describes a rapid, simple and sensitive analytical method for the quantitative determination of melatonin in human serum by ESI–MS–MS with direct serum sample injection and on-line extraction. The method uses N-acetyltryptamine as the internal standard. It has high specificity and sensitivity for serum melatonin analysis. The internal calibration curve shows a wide linear range from 0.500 to 200 ng/ml with a correlation coefficient, R2>0.999. The limit of quantitation is 0.500 ng/ml and the limit of detection is 0.100 ng/ml with 10-μl sample injection. The recoveries of serum melatonin at three levels are approximately 70%. The intra-assay precision …

University Of Nevada, Las Vegas Advanced Accelerator Applications University Participation Program: Quarterly Report, Third Quarter Year 2 (Sept. 2002 To Nov. 2002), Anthony Hechanova

Transmutation Research Program Reports (TRP)

This Quarterly Report is a primary deliverable from the University of Nevada, Las Vegas (UNLV) Advanced Accelerator Applications (AAA) University Participation Program (UPP) Director to the U.S. Department of Energy (DOE) as described in the UNLV AAA proposal and Statement of Work for the Fourth Quarter.

The UNLV AAA UPP Director implements the program’s administration using staff from the Harry Reid Center for Environmental Studies (HRC) to ensure that work conducted under the UNLV AAA UPP meets program objectives. The UNLV AAA program consists of three components: Program Support, Research Infrastructure Augmentation, and Student Research.

Deliquescence Behavior Of Organic/Ammonium Sulfate Aerosol, Sarah D. Brooks, Matthew E. Wise, Melinda Cushing, Margaret A. Tolbert

CUP Faculty Research

Recent studies have shown that tropospheric aerosols composed of internal mixtures of organics with sulfates are quite common with the organic composing up to 50% of the particle mass. The influences of the organics on the chemical and physical properties of the aerosol are not known. In this paper, we report the solubility of a series of dicarboxylic acids in saturated ammonium sulfate solution as a function of temperature. We also report the deliquescence relative humidity (DRH) of the pure dicarboxylic acids and of mixtures of dicarboxylic acids with ammonium sulfate. For the systems studied, we find that the presence …

Kinetic And Structural Characterization Of Manganese(Ii)-Loaded Methionyl Aminopeptidases, Ventris M. D'Souza, Sabina I. Swierczek, Nathaniel J. Cosper, Lu Meng, Shane Ruebush, Alicja J. Copik, Robert A. Scott, Richard C. Holz

Chemistry Faculty Research and Publications

Manganese(II) activation of the methionyl aminopeptidases from Escherichia coli (EcMetAP-I) and the hyperthermophilic archaeon Pyrococcus furiosus (PfMetAP-II) was investigated. Maximum catalytic activity for both enzymes was obtained with 1 equiv of Mn(II), and the dissociation constants (K_d) for the first metal binding site were found to be 6 ± 0.5 and 1 ± 0.5 μM for EcMetAP-I and PfMetAP-II, respectively. These K_d values were verified by isothermal titration calorimetry (ITC) and found to be 3.0 ± 0.2 and 1.4 ± 0.2 μM for EcMetAP-I and PfMetAP-II, respectively. The …

2. Toshinobu Higashimura, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.

Chemistry & Biochemistry Newsletter, Department Of Chemistry & Biochemistry, South Dakota State University

Chemistry & Biochemistry Newsletter: 2002-2015

Inside:

Page 2 Utecht Enhances Freshman Labs with New Software

Page 3 Alumni News; Foundation donors

Page 4 2002 Graduates and Awards; Chinese Seminar Results in Research Project

Page 5 Faculty and Staff News

Page 6 Antarctic Ice Holds History of Earth’s Atmosphere; Renovations of Shepard Hall Complete

Page 7 ASL Staff Records Hectic Summer; Budner Attends Greek Conference ; Carlson Awarded National Scholarship

Page 8 Recent Faculty Publications

A Comparison Of The Low Mode And Monte Carlo Conformational Search Methods, Carol A. Parish, Rosina Lombardi, Kent Sinclair, Emelyn Smith, Alla Goldberg, Melissa Rappleye, Myrianne Dure

Chemistry Faculty Publications

The Low Mode (LM) and Monte Carlo (MC) conformational search methods were compared on three diverse molecular systems; (4R, 5S, 6S, 7R)-hexahydro-5,6-dihydroxy-1,3,4,7-tetrakis(phenylmethyl)-2H-1,3-diazapin-2-one (1), 2-methoxy-2-phenyl-2-triflouromethyl-N-α-methyl benzyl propanamide (2) and a trimeric 39-membered polyazamacrolide (3). We find that either method, or a combination of the methods, is equally efficient at searching the conformational space of the smaller molecular systems while a 50:50 hybrid of Low Mode and Monte Carlo is most efficient at searching the space of the larger molecular system.

Structural Biology Of Bacterial Multidrug Resistance Gene Regulators, Michael H. Godsey, Ekaterina E. Zheleznova Heldwein, Richard G. Brennan

CUP Faculty Research

Multidrug resistance (mdr)¹ can be defined broadly as the ability of a cell to survive ordinarily lethal doses of more than one drug. Clearly, such resistance is a critical problem in the treatment of fungal and bacterial infections and cancer. Four general, but nonexclusive, mechanisms give rise to multidrug resistance: 1) detoxification by enzymatic modification or cleavage of drug; 2) genetic alteration of the intra- or extracellular targets; 3) decreased permeability of the cell membrane; and 4) active drug extrusion by multidrug transporters.

Paramount to our understanding of mdr is the issue of recognition of structurally dissimilar substrates and …

Guanine And 7,8-Dihydro-8-Oxo-Guanine-Specific Oxidation In Dna By Chromium(V), Kent D. Sugden, Brooke Martin

Chemistry and Biochemistry Faculty Publications

The hexavalent oxidation state of chromium [Cr(VI)] is a well-established human carcinogen, although the mechanism of cancer induction is currently unknown. Intracellular reduction of Cr(VI) forms Cr(V), which is thought to play a fundamental role in the mechanism of DNA damage by this carcinogen. Two separate pathways of DNA damage, an oxidative pathway and a metal-binding pathway, have been proposed to account for the lesions observed in cell systems. We have used a model Cr(V) complex, N,N´-ethylenebis(salicylidene-animato)oxochromium(V) [Cr(V)-Salen], to investigate the oxidative pathway of DNA damage and to elucidate the lesions generated from this oxidation process. Reaction of Cr(V)-Salen with …

The Aminopeptidase From Aeromonas Proteolytica: Structure And Mechanism Of Co-Catalytic Metal Centers Involved In Peptide Hydrolysis, Richard C. Holz

Chemistry Faculty Research and Publications

Enzymes containing multi-metal active sites are central to numerous biological processes and, consequently, characterization of their structure and function is a problem of outstanding importance. One of the least-explored groups of enzymes is the hydrolases that contain dinuclear metal centers. These enzymes play key roles in carcinogenesis, tissue repair, and protein degradation processes. In addition, some of these enzymes can catalyze the hydrolysis of phosphorus(V) compounds found in nerve gases and agricultural neurotoxins. The determination of detailed reaction mechanisms for these enzymes is required for the design of highly potent, specific inhibitors that can function as potential pharmaceuticals. Hydrolytic enzymes …