Open Access. Powered by Scholars. Published by Universities.®

Chemistry Commons™

Open Access. Powered by Scholars. Published by Universities.®

2008

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 451 - 480 of 713

Full-Text Articles in Chemistry

Mutational Analysis Of The Stability Of The H2a And H2b Histone Monomers, Matthew R. Stump, Lisa M. Gloss Jan 2008

Mutational Analysis Of The Stability Of The H2a And H2b Histone Monomers, Matthew R. Stump, Lisa M. Gloss

Faculty Publications - Department of Biological & Molecular Science

The eukaryotic histone heterodimer H2A–H2B folds through an obligatory dimeric intermediate that forms in a nearly diffusion-limited association reaction in the stopped-flow dead time. It is unclear whether there is partial folding of the isolated monomers before association. To address the possible contributions of structure in the monomers to the rapid association, we characterized H2A and H2B monomers in the absence of their heterodimeric partner. By far-UV circular dichroism, the H2A and H2B monomers are 15% and 31% helical, respectively—significantly less than observed in X-ray crystal structures. Acrylamide quenching of the intrinsic Tyr fluorescence was indicative of tertiary structure. The …

Go to article

Plasma Surface Modifications For Biomedical And Electrical Applications, Dhiman Bhattacharyya Jan 2008

Plasma Surface Modifications For Biomedical And Electrical Applications, Dhiman Bhattacharyya

Chemistry & Biochemistry Dissertations - Archive

The focus of this work centers on molecular structuring of surfaces. The surface modifications were achieved using plasma polymerization technology, specifically variable duty cycle pulsed plasmas. The results obtained demonstrate that both exacting film chemistry and film thickness control were achieved during deposition of thin polymeric films on selected substrates. The following achievements are detailed in this thesis:* Identification of a new class of volatile monomers which can be successfully used to synthesize thermoresponsive hydrogel films. A unique aspect of this work is that the lower critical solution temperatures of these gels can be controllably varied by simple adjustment of …

Go to article

Cytotoxicity Studies On Metallo-Salens And Their Applications In Gene Delivery, Getachew Abebe Woldemariam Jan 2008

Cytotoxicity Studies On Metallo-Salens And Their Applications In Gene Delivery, Getachew Abebe Woldemariam

Chemistry & Biochemistry Dissertations - Archive

Most of biological catalysts including nucleases are made of active metal centers. Metal complexes that are able to interact with DNA and RNA mimicking these natural nucleases will be valuable as therapeutic agents that target nucleic acids. Metal complexes have been used for very long time to treat different kinds of illnesses including cancer. Platinum based compounds are among the most widely used anticancer agents in clinical use. The first chapter of this dissertation highlights the roles of metal ions and their complexes with regard to biochemical activities, as enzyme inhibitors, anticancer agents and metallo-nucleases. Moreover, we will discuss the …

Go to article

Development And Application Of New Mass Spectrometry-Based Proteomics Technologies To Post-Translational Modifications, Yue Chen Jan 2008

Development And Application Of New Mass Spectrometry-Based Proteomics Technologies To Post-Translational Modifications, Yue Chen

Chemistry & Biochemistry Dissertations - Archive

Post-translational modifications (PTMs) represent one of the major cellular mechanisms to diversify the limited number of proteins coded by genome. They provide dynamic regulation of protein functions and the means to fine-tune protein functions in response to the changing cellular environment and physiological conditions. Despite their crucial roles in cellular functions, efficient and sensitive analysis of PTMs remains a daunting analytical challenge. Traditional chemical approaches to characterize PTMs are labor-intensive and time-consuming, often with low sensitivity and specificity. Over the past ten years, biological mass spectrometry has emerged as an indispensable tool to identify and characterize PTMs. Mass spectrometry-based proteomic …

Go to article

Statistically Designed Experiments In The Examination Of Factors Influencing Regioselectivity In Electrophilic Aromatic Substitution Reactions, Jason Adam Mann Jan 2008

Statistically Designed Experiments In The Examination Of Factors Influencing Regioselectivity In Electrophilic Aromatic Substitution Reactions, Jason Adam Mann

Theses & Honors Papers

Statistically designed experiments were developed and executed in order to determine the effects of several variables on the regiochemistry of electrophilic aromatic substitution (EAS) reactions. One experiment employed the electrophilic aromatic bromination of phenol, and indicated that temperature and concentration had statistically insignificant effects on the product composition of the reaction , while the mole ratio of bromine to phenol and percent water content of the solvent had significant effects at the 95% confidence level (i.e. a=0.05). Another experiment investigated the Friedel-Craf ts acylation of three butylbenzene isomers, and showed that temperature and reaction time had insignificant influences on product …

Go to article

Dms Air/Sea Flux And Gas Transfer Coefficients From The North Atlantic Summertime Coccolithophore Bloom, Christa Marandino, Warren J. De Bruyn, Scott Miller, Eric S. Saltzman Jan 2008

Dms Air/Sea Flux And Gas Transfer Coefficients From The North Atlantic Summertime Coccolithophore Bloom, Christa Marandino, Warren J. De Bruyn, Scott Miller, Eric S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Dimethylsulfide (DMS) atmospheric and oceanic concentrations and eddy covariance air/sea fluxes were measured over the N. Atlantic Ocean during July 2007 from Iceland to Woods Hole, MA, USA. Seawater DMS levels north of 55 degrees N ranged from 3 to 17 nM, with variability related to the satellite-derived distributions of coccoliths and to a lesser extent, chlorophyll. For the most intense bloom region southwest of Iceland, DMS air/sea fluxes were as high as 300 mu mol m(-2) d(-1), larger than current model estimates. The observations imply that gas exchange coefficients in this region are significantly greater than those estimated using …

Go to article

Synthesis And Dye Leakage Assay Of Human And Rat Islet Amyloid Polypeptide 10-19 And Insulin 14-18, Andrew William Gray Jan 2008

Synthesis And Dye Leakage Assay Of Human And Rat Islet Amyloid Polypeptide 10-19 And Insulin 14-18, Andrew William Gray

Master's Theses and Doctoral Dissertations

Islet amylin polypeptide (IAPP) is co-secreted along with insulin in the pancreatic islets of Langerhans. During type 2 diabetes mellitus, human IAPP (hIAPP) fibrilizes to form amyloid deposits that are found post-mortem in more than 95% of people with the disease. Rodents do not suffer from type 2 diabetes mellitus as their IAPP (rIAPP) does not undergo self-aggregation. Although the amyloid deposit is found in those with the disease, the actual cause of the disease is the cytotoxicity of the mechanism that forms those amyloid deposits. The self-aggregation of IAPP to form amyloid deposits is inhibited by insulin due to …

Go to article

Spectroscopy Is Applied Quantum Mechanics. Part 2: The Quantum Revolution, David W. Ball Jan 2008

Spectroscopy Is Applied Quantum Mechanics. Part 2: The Quantum Revolution, David W. Ball

Chemistry Faculty Publications

The article presents several theories relative to the nature of matter. The quantum theory of German theoretical physicist Max Planck proposes that the energy of a vibrating atom was related to its frequency. Albert Einstein's quantum theory of light hypothesizes that light itself had an energy that was directly proportional to its frequency. Danish physicist Niels Bohr develops an equation that could help explain the lines that appeared in the spectrum of the hydrogen atom.

Go to article

Staphylococcus Aureus Primase Has Higher Initiation Specificity, Interacts With Single-Stranded Dna Stronger, But Is Less Stimulated By Its Helicase Than Escherichia Coli Primase, Scott A. Koepsell, Marilynn A. Larson, Christopher Frey, Steven H. Hinrichs, Mark A. Griep Jan 2008

Staphylococcus Aureus Primase Has Higher Initiation Specificity, Interacts With Single-Stranded Dna Stronger, But Is Less Stimulated By Its Helicase Than Escherichia Coli Primase, Scott A. Koepsell, Marilynn A. Larson, Christopher Frey, Steven H. Hinrichs, Mark A. Griep

Mark A. Griep Publications

The study of primases from model organisms such as Escherichia coli, phage T7 and phage T4 has demonstrated the essential nature of primase function, which is to generate de novo RNA polymers to prime DNA polymerase. However, little is known about the function of primases from other eubacteria. Their overall low primary sequence homology may result in functional differences. To help understand which primase functions were conserved, primase and its replication partner helicase from the pathogenic Gram-positive bacteria Staphylococcus aureus were compared in detail with that of E. coli primase and helicase. The conserved properties were to primer initiation …

Go to article

Solution Processible Aromatic Polyimides Via Diels Alder Precursor, Saral Shah Jan 2008

Solution Processible Aromatic Polyimides Via Diels Alder Precursor, Saral Shah

Electronic Theses and Dissertations

Aromatic polyimides are interesting materials since they possess outstanding key properties such as thermoxidative stability, high mechanical strength, high modulus, excellent electrical properties, and superior chemical resistance. However, their low solubility makes them difficult to characterize, process and obtain high molecular weight polymer. In this report, we synthesized a series of precursor polymers that contains Diels-Alder (DA) adducts of anthracene. Different dienophiles were tried. These precursor polymers are soluble in common organic solvents such as chloroform and can be easily processed to thin films. Heating the film above 215 degree induce retro-DA reaction, which generated the fully aromatic polyimides in …

Go to article

Investigation Of Redox-Active Ruthenium(Ii) Polypyridyl Complexes As Potential Anti-Cancer Drugs, Abhishek Yadav Jan 2008

Investigation Of Redox-Active Ruthenium(Ii) Polypyridyl Complexes As Potential Anti-Cancer Drugs, Abhishek Yadav

Chemistry & Biochemistry Dissertations - Archive

Stereospecific binding of ruthenium metallointercalators with DNA is of particular interest because of the potential for improved targeting of specific sites in DNA. The present studies are focused on new metallointercalator, ruthenium (II) polypyridyl complex [(phen) 2 Ru(tatpp)(phen) 2 ]Cl 4 , [P p ] 4+ , and it's structural analog [Ru(phen) 2 (tatpp)]Cl 2 , [MP p ] 2+ ; the latter contains a redox active bridging ligand tatpp (where tatpp = 9,11,20,22-tetraazatetrapyrido[3,2-a:2',3'-c:3'',2''-l:2''',3'''-n]-pentacene and phen = 1,10-phenanthroline). Complex [P p ] 4+ exists as a mixture of ΔΔ-, ΔΔ- and ΔΔ- stereisomers whereas [MP p ] 2+ exists as …

Go to article

Polyaniline Nanofiber-Based Gas Sensors, Zhe-Fei Li, Frank D. Blum, Massimo F. Bertino, Chang-Soo Kim Jan 2008

Polyaniline Nanofiber-Based Gas Sensors, Zhe-Fei Li, Frank D. Blum, Massimo F. Bertino, Chang-Soo Kim

Chemistry Faculty Research & Creative Works

There has been recent interest in conducting polymers that have very promising chemical and electrical applications. Some of these polymers have shown great potential for use in sensors.1 Polyaniline is one particular example of a prospective material. In our laboratory, we have studied the synthesis of polyaniline nanofibers. We have carried out one-pot syntheses to obtain polyaniline nanofibers in aqueous solutions where the polymerization was influenced by γ-radiation2 or UV-radiation.3 This polymer can also be patterned with an appropriate photo mask. In our present report, polyaniline nanofiber thin film sensors have been fabricated in one step by employing UV-irradiation and …

Go to article

Thermal Analysis Of Adsorbed Poly(Vinyl Acetate) On Silica, Boonta Hetayothin, Frank D. Blum Jan 2008

Thermal Analysis Of Adsorbed Poly(Vinyl Acetate) On Silica, Boonta Hetayothin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The physical properties of polymers at interfaces can be quite different from those in bulk due to the interaction between the absorbed polymer and the surface. This phenomenon can be probed through the dynamic behavior of the polymer chains at the interface which can be experimentally probed by techniques such as nuclear magnetic resonance spectroscopy (NMR),1 viscoelasticity, and calorimetry. At the polymer-air interface, polymer chains have more flexibility than those at the polymer-substrate interface. On the other hand, at the silica-polymer interface, where chains are more restricted on the surface, a higher glass transition temperature (Tg) results as compared with …

Go to article

Assemblies Of Nanoparticles As 3d Scaffolds For New Materials Design: From Polymer Crosslinked Aerogels To Polymer Matrix Composites, Nicholas Leventis, Chariklia Sotiriou-Leventis, Sudhir Mulik, Vishal U. Patil, Dhairyashil Mohite, Yanli Zhang, Hongbing Lu Jan 2008

Assemblies Of Nanoparticles As 3d Scaffolds For New Materials Design: From Polymer Crosslinked Aerogels To Polymer Matrix Composites, Nicholas Leventis, Chariklia Sotiriou-Leventis, Sudhir Mulik, Vishal U. Patil, Dhairyashil Mohite, Yanli Zhang, Hongbing Lu

Chemistry Faculty Research & Creative Works

From a materials perspective, nanotechnology furnishes materials with useful macroscopic properties by manipulating matter in the 1-100 nm size regime. Improvements in performance in terms of strength, modulus and wetability are accomplished by, for example, introducing nanoparticles as fillers in plastics . Two issues that usually interfere with optimal materials performance are agglomeration of the nanoparticles and materials compatibility. Agglomeration cancels the advantage of using nanoparticulate matter as dopant, while lack of materials compatibility introduces a discontinuity at the polymer/dopant interface from where failure may begin. Agglomeration is encountered with surfactants that keep nanoparticles dispersed, while materials compatibility is improved …

Go to article

Dynamics Of Adsorbed Pma-D₃ - Effect Of Substrate, Frank D. Blum, Burak Metin, Macduff O. Okuom Jan 2008

Dynamics Of Adsorbed Pma-D₃ - Effect Of Substrate, Frank D. Blum, Burak Metin, Macduff O. Okuom

Chemistry Faculty Research & Creative Works

In the last few years, our group has focused much of our attention on studying the dynamics of polymers adsorbed at interfaces. Much of our work, to date has been on labeled poly(vinyl acetate)-d3 (PVAc-d3)1 and poly(methyl acrylate)-d3 (PMA-d3)2 on silica. We have been able to probe the effects of adsorbed amount,3 molecular mass,4,5 and the effect of overlayer.6 These studies have provided a view of the adsorbed polymer consistent with a motional gradient in the layer with the more mobile segments being those at the air-polymer interface and the less-mobile segments at the substratepolymer interface. However, we have not …

Go to article

Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry For The Analysis Of Collected Bioaerosols, Alton John Dugas Jan 2008

Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry For The Analysis Of Collected Bioaerosols, Alton John Dugas

LSU Doctoral Dissertations

The goal of this dissertation was to demonstrate collection, detection and identification of microorganisms from bioaerosols using offline matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the analysis of proteins. MALDI-MS intact bacteria techniques were adapted for use with an orthogonal MALDI quadrupole-time-of-flight mass spectrometer. Results indicate the instrument is capable of analyzing intact whole-cells. The first phase was to evaluate three bioaerosol samplers, an Andersen N6 single-stage impactor (AI), a cyclone impactor, and a vacuum filter system. The samplers collected test bioaerosols using a constructed bioaerosol exposure chamber (BEC). The BEC allowed all three samplers to operate in parallel. Each …

Go to article

Gas-Phase Formation Of Environmentally Persistent Free Radicals From Thermal Degradation Of Catechol, Hydroquinone, Phenols And Tobacco, Julien Gnonlonfoun Adounkpe Jan 2008

Gas-Phase Formation Of Environmentally Persistent Free Radicals From Thermal Degradation Of Catechol, Hydroquinone, Phenols And Tobacco, Julien Gnonlonfoun Adounkpe

LSU Doctoral Dissertations

Catechol, hydroquinone and Phenol are major constituents of the mainstream tobacco smoke. The toxicity of tobacco has been attributed to the ability of catechol and hydroquinone to undergo endogenous or exogenous redox cycling to form semiquinone type radicals responsible of Reactive Oxygen Species (ROS) formation. ROS such as hydroxyl radicals can cause severe oxidative stress on biological tissues and can provoke severe signaling pathways leading to cardiovascular and pulmonary dysfunctions and carcinogenesis. Given that semiquinone type radicals are organic radicals, characterized by their high instability and reactivity; it is somewhat surprising that they can live long enough mostly when associated …

Go to article

A Study Of Rheological And Thermodynamic Properties Of Polymer-Clay Gels And Multilayered Films, Eduard Adrian Stefanescu Jan 2008

A Study Of Rheological And Thermodynamic Properties Of Polymer-Clay Gels And Multilayered Films, Eduard Adrian Stefanescu

LSU Doctoral Dissertations

The overall objective of the research presented here is to understand the nanoscopic and microscopic structures that exist in dispersions of laponite and montmorillonite in poly(ethylene oxide), (PEO) and to correlate their shear responses with the final structure and properties of multilayered nanocomposite films prepared from these dispersions. These structures were examined as a function of polymer molecular weight, polymer and clay concentrations, and type of clay used to prepare the nanocomposites. A sequence of shear and elongational rheological measurements is used to provide a more complete physical picture on the structure of polymer-clay hydrogels, while a combination of techniques …

Go to article

Off-Line Maldi Mass Spectrometry Of Bioaerosols, Jae-Kuk Kim Jan 2008

Off-Line Maldi Mass Spectrometry Of Bioaerosols, Jae-Kuk Kim

LSU Doctoral Dissertations

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used for off-line analysis of bioaerosols. The overall goal of the work is to develop methods and instrumentation to minimize sample treatment and maximize sensitivity and selectivity for bioaerosol analysis. This work is divided into three parts: sample preparation, test bioaerosol analysis, and instrument development. Untreated silicon wafer substrates were used as an alternate to conventional stainless steel targets and proved to be excellent substrates for large molecule analyses as well as small molecule analyses with excellent spot-to-spot and shot-to-shot reproducibility, which is useful for high-throughput and automated sample analysis. MALDI sample preparation …

Go to article

Investigation Of Antimonide Structure Types And The Structural Studies Of Molybdates, Dixie Plaisance Gautreaux Jan 2008

Investigation Of Antimonide Structure Types And The Structural Studies Of Molybdates, Dixie Plaisance Gautreaux

LSU Doctoral Dissertations

This dissertation highlights the investigation of ternary lanthanide antimonide structure types and their physical properties. In particular, these ternary phases allow for the systematic investigation of the structure in an effort to correlate structure and properties. The ternary antimonides are layered structures with two-dimensional square sheets or nets, which influence the properties of these materials. In an effort to determine how structural changes influence the physical properties, various single crystals of compounds relating to the orthorhombic CeNiSb3 structure have been grown and characterized. The layered CeNiSb3 structure consists of Sb sheets, NiSb6 distorted octahedra, and CeSb9 monocapped square anti-prisms. LnNi(Sn,Sb)3 …

Go to article

In Situ Attenuated Total Internal Reflection Fourier Transform Infrared (Atr Ft-Ir) Spectroscopy Coupled With Multivariate Least Squares Analysis For The Study Of Polyelectrolytes/Surfactant Systems At The Tio2/Water Interface, Michael Hase Jan 2008

In Situ Attenuated Total Internal Reflection Fourier Transform Infrared (Atr Ft-Ir) Spectroscopy Coupled With Multivariate Least Squares Analysis For The Study Of Polyelectrolytes/Surfactant Systems At The Tio2/Water Interface, Michael Hase

Undergraduate Honors Theses

ATR-FTIR provides the ability to study interfacial interactions in situ. ATR-FTIR was used to obtain infrared spectroscopic information about the interactions between the titanium dioxide surface, the polyelectrolyte sodium styrene sulfonate (PSS), and the surfactant cetylpyridinium bromide momhydrate (CBMD). The IR data was then modeled with a Frumkin isotherm and analyzed using a multidimensional least squares technique.

Go to article

Pressure Perturbation Calorimetry And Guest-Host Chemistry Of Ndmg And N-Map With P-Sulfonatocalix[6]Arene, Cassandra Newell Jan 2008

Pressure Perturbation Calorimetry And Guest-Host Chemistry Of Ndmg And N-Map With P-Sulfonatocalix[6]Arene, Cassandra Newell

Honors Theses

The aim of this project is to provide an explanation for recently obtained binding constants for two similar guest molecules, NDMG and N-MAP, with a p-sulfonatocalix[6]arene host in ammonium acetate buffer. This work was done primarily using pressure perturbation calorimetry, which is a technique that determines the coefficient of thermal expansion, α, which is in turn related to the solute molecule's effect on the order of the surrounding water molecules. A series of experiments were designed to test the effects of suspected confounding variables on the validity of PPC data. PPC was then used to study NDMG and N-MAP in …

Go to article

Using Azahetercyclic Electrophiles To Synthesize Novel Bicyclooxacalixarenes And Oxacalix[2]N-Hexylnaphthalimide[2]Naphthyridines, Doug Rooke Jan 2008

Using Azahetercyclic Electrophiles To Synthesize Novel Bicyclooxacalixarenes And Oxacalix[2]N-Hexylnaphthalimide[2]Naphthyridines, Doug Rooke

Honors Theses

Various bicyclooxacalixarenes, tricyclooxacalixarenes and oxacalix[2]N-hexylnapthalimide[2]naphthyridines are synthesized via SnAr condensation. This research has involved synthesis optimization. The oxacalix[2]N-hexylnaphthalimide[2]naphthyridines have exhibited host-guest binding in fluorescence experiments. These compounds have been characterized by NMR spectroscopy as well as single crystal X-ray diffraction.

Go to article

Photochemical Generation And Intramolecular Chemistry Of Β-Alkoxycarbenes, Kimberly Graves Jan 2008

Photochemical Generation And Intramolecular Chemistry Of Β-Alkoxycarbenes, Kimberly Graves

Honors Theses

The photolytic phenanthrene-based precursors for both β-methoxycarbene and β-ethoxycarbene were synthesized with and without a deuterium label attached to the a carbon. The incorporation of this deuterium label allowed distinction between a 1, 2-H shift and a 1, 2-O shift pathway to the respective alkyl vinyl ether, without the influence of a primary kinetic isotope effect. Photolyses of these precursors gave rearrangement products of the expected β-alkoxycarbenes. In the case of β-methoxycarbene, no methyl vinyl ether was observed due to its volatility. However, the appearance of aldehyde peaks in the NMR spectra, from an apparent further rearrangement to acetaldehyde through …

Go to article

Reactions Of Atomic Carbon With Acid Chlorides, Daniel B. Herrick Jan 2008

Reactions Of Atomic Carbon With Acid Chlorides, Daniel B. Herrick

Honors Theses

This thesis is the first report of reactions of atomic carbon with acid chlorides. Carbon is known to react with phosgene to afford dichlorocarbene. We report a similar reaction with carbon and acid chlorides, generating alkylchlorocarbenes. We examine both the nature of the carbene products generated through deoxygenation and the general reactivity of carbon with the acid chlorides. We report two ways in which carbon reacts with acid chlorides. First, as expected from prior work with phosgene, carbon deoxygenates the carbonyl group yielding alkylchlorcarbenes, which rearrange as expected. Second, carbon abstracts the chlorine, and generates the acyl radical, which, in …

Go to article

The Selective Synthesis Of Oxacalix[6]Arenes And The Exploration Of Azacalix[N]Arenes, W. Christian Crannell Jan 2008

The Selective Synthesis Of Oxacalix[6]Arenes And The Exploration Of Azacalix[N]Arenes, W. Christian Crannell

Honors Theses

Calix[n]arenes, cyclIc molecules composed of "n" benzene rings meta-linked by a methylene to form a macrocycle, are very prevalent jn the literature and enjoy a wide range of applications. However, the oxygen bridged and nitrogen bridged systems, oxacalllx[n)arenes and azacalix[n]arenes, respectively, are far less common because they are synthetically challenging. Furthermore, the selective synthesis of oxacalix[6]arene systems has not previously been well documented, but the systems can now be accessed in a facile approach disclosed here. The insight and knowledge gained from the synthesis of oxacalix{6]arenes has provided a foray into the synthesis of azacalix[nlarenes.

Go to article

Effects Of The Anticancer Agent Cloretazine On Human Apurinic Endonuclease-1 Activity, Jennifer L. Bushee Jan 2008

Effects Of The Anticancer Agent Cloretazine On Human Apurinic Endonuclease-1 Activity, Jennifer L. Bushee

Honors Theses

The carbamolyating activity of Cloretazine, a novel anticancer prodrug, modifies protein function and acts synergistically with the choroethyalting species, which a1kylales DNA. The reactive subspecies responsible for carbamolylating activity is methyl isocyanate, which reacts with sulfhydryl groups and amines. DNA repair enzymes have been identified as potential targets for the modification by methyl isocyanate; in particular, base excision repair enzymes. Enzymes in DNA base excision repair include DNA polymerase beta (Pol ?) and apurinic/apyrimidic endonucease-l (APE/Ref-1). APE/Ref-1 hydrolyzes the 5' -phosphodiester DNA backbone from an abasic DNA template, where the base was excised by a DNA glycosylase. The entire nucleotide …

Go to article

A Tribute To Peter George Brewer In Celebration Of His 65th Birthday, George T. F. Wong, Robert F. Anderson, Michael P. Bacon, Hein J. W. De Baar, James W. Murray, Mary I. Scranton Jan 2008

A Tribute To Peter George Brewer In Celebration Of His 65th Birthday, George T. F. Wong, Robert F. Anderson, Michael P. Bacon, Hein J. W. De Baar, James W. Murray, Mary I. Scranton

OES Faculty Publications

Peter George Brewer is an ocean chemist of the rare breed that can cross back and forth over the divide between being a front-line research scientist and being a research executive. As if that is not remarkable enough, in the process, he has also demonstrated sustained growth in the depth, breadth, and diversity of his scientific endeavors. Some of his formidable contributions to ocean chemistry have already been highlighted in a profile of him as a major mover and shaker in the field (Irion, 2001). Here, we provide additional glimpses of him from the perspective of a group of individuals …

Go to article

Naturally Present Fatty Acids As Internal Calibrants For Fourier Transform Mass Spectra Of Dissolved Organic Matter, Rachel L. Sleighter, Georgina A. Mckee, Zhanfei Liu, Patrick G. Hatcher Jan 2008

Naturally Present Fatty Acids As Internal Calibrants For Fourier Transform Mass Spectra Of Dissolved Organic Matter, Rachel L. Sleighter, Georgina A. Mckee, Zhanfei Liu, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

The analysis of dissolved organic matter ( DOM) by Fourier transform ion cyclotron resonance mass spectrometry ( FTICR- MS) has gained wide interest recently, driven primarily by its ultrahigh resolving power and mass accuracy. Accurate calibration of mass spectra is a key step to successfully decipher the DOM components. We propose a simple and accurate method to internally calibrate the peaks in the complex spectra without the need to add a calibrant. Mass spectra of DOM samples from the Dismal Swamp, Virginia, and the lower Chesapeake Bay display the presence of naturally occurring fatty acids which can be readily recognized …

Go to article

Determination Of Photochemically Produced Carbon Dioxide In Seawater, Emily M. White, David J. Kieber, Kenneth Mopper Jan 2008

Determination Of Photochemically Produced Carbon Dioxide In Seawater, Emily M. White, David J. Kieber, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

An analytical system was developed to determine photochemically produced carbon dioxide in marine waters. Our system was designed to measure low levels of carbon dioxide by maintaining a closed system to prevent atmospheric contamination during sample preparation, irradiation, and analysis. To detect low levels of photoproduced carbon dioxide in seawater, background dissolved inorganic carbon (DIC) was removed before irradiation. To strip out DIC, samples were acidified to pH 3.0 (converting DIC to carbon dioxide) and bubbled with low carbon dioxide air. The pH was then readjusted back to the original value, and the resulting low-DIC seawater samples were transferred pneumatically …

Go to article

First Prev Next Last