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

Digital Commons Network™

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

Chemistry

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 13411 - 13440 of 15533

Full-Text Articles in Entire DC Network

Microwave Reflectometry As A Novel Diagnostic Tool For Detection Of Skin Cancers, Pratik Mehta, Kundan Chand, Deepak Narayanswamy, Daryl G. Beetner, R. Zoughi, William V. Stoecker Aug 2006

Microwave Reflectometry As A Novel Diagnostic Tool For Detection Of Skin Cancers, Pratik Mehta, Kundan Chand, Deepak Narayanswamy, Daryl G. Beetner, R. Zoughi, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

More than 1 000 000 people are diagnosed with skin cancer each year in the United States, and more than 10 000 people die from the disease. Methods such as visual inspection and dermoscopy are available for early detection of skin cancers, but improvement in accuracy is needed. This paper investigates the use of microwave reflectometry as a potential diagnostic tool for detection of skin cancers. Open-ended coaxial probes were used to measure microwave properties of skin. The influences of measurement parameters such as probe application pressure, power level, and variation in reflection properties of skin with location and hydration …

Go to article

Water Solubility Characteristics Of Hydrophobically Modified Polyethyleneimines, Jennifer N. Williams Aug 2006

Water Solubility Characteristics Of Hydrophobically Modified Polyethyleneimines, Jennifer N. Williams

Browse all Theses and Dissertations

Commercially available polyethyleneimines varying in molecular weights and viscosities were synthetically modified in order to increase their hydrophobicity when dissolved in water. Used as additives for inkjet industry inks, these polymers have been designed to promote interaction between formulated inks and paper, while increasing the water-fastness of these water-soluble inks once they are dried on bond paper. Waterfastness, the ability of an ink to maintain print integrity once it becomes wet, as well as optical density, solubility, pH, molecular weight, polydispersity and viscosity are amongst the characteristics analyzed. The modifications of these polyethyleneimines (PEis) with alkyl bromides and alkyl epoxides …

Go to article

Physico-Chemical And Grain Cooking Characteristics Of Selected Rice Cultivars Grown In Morogoro, N.B. Shayo, P. Mamiro, C. N. M. Nyaruhucha, T. Mamboleo Jul 2006

Physico-Chemical And Grain Cooking Characteristics Of Selected Rice Cultivars Grown In Morogoro, N.B. Shayo, P. Mamiro, C. N. M. Nyaruhucha, T. Mamboleo

Tanzania Journal of Science

A study was carried out at Sokoine University of Agriculture to characterize the local rice varieties grown in Morogoro Region basing on their physical-chemical characteristics and cooking quality parameters. Five cultivars of rice were analyzed and these included Kaling'anaula, Kihogo Red, Salama M17, Supa and Salama. The samples were collected from Crop museum, SUA. The chemical analysis was done to determine the proximate composition, gelatinization temperature and gel consistency as main determinants of cooking quality, sensory evaluation tests was done as determinants for consumer acceptance. The proximate composition results indicated protein content values between 7.94 and 9.46%, ash content between …

Go to article

Stable Isotope Compositions Of Organic Carbon And Contents Of Organic Carbon And Nitrogen Of Lacustrine Sediments From Sub-Arid Northern Tanzania, Ann Muzuka Jul 2006

Stable Isotope Compositions Of Organic Carbon And Contents Of Organic Carbon And Nitrogen Of Lacustrine Sediments From Sub-Arid Northern Tanzania, Ann Muzuka

Tanzania Journal of Science

The stable isotope compositions of organic carbon (OC), and contents of OC and nitrogen for four sediment cores recovered from lakes Makat (located in the Ngorongoro Crater), Ndutu and Masek (located in the Serengeti Plains) are used to document sources of organic matter (OM) and climatic changes in sub-arid northern Tanzania during the late Pleistocene-Holocene period. Accelerate mass spectrometer (AMS) 14C ages on total OM for sediments collected from the Ngorongoro Crater Lake indicate that the sedimentation rate is approximately 17 cm/ka. The δC values from the 20 cm long core (short core) show a downcore increase, whereas that of …

Go to article

Photoreductive Dissolution Of Ferrihydrite By Methanesulfinic Acid: Evidence Of A Direct Link Between Dimethylsulfide And Iron-Bioavailability, Anne M. Johansen, Jennifer M. Key Jul 2006

Photoreductive Dissolution Of Ferrihydrite By Methanesulfinic Acid: Evidence Of A Direct Link Between Dimethylsulfide And Iron-Bioavailability, Anne M. Johansen, Jennifer M. Key

All Faculty Scholarship for the College of the Sciences

Within open‐ocean regions where excess macronutrients are present, phytoplankton growth is limited by the bioavailability of iron supplied to these areas primarily within atmospheric aerosols of crustal origin. However, processes that control the abundance of biologically accessible iron in these aerosols are largely unknown. Here we show that dissolution of ferrihydrite, a surrogate iron(oxy)hydroxide phase found in atmospheric waters, is enhanced in the presence of methanesulfinic acid (MSIA, CH3SO2H, a dimethylsulfide (DMS) oxidation intermediate) in laboratory irradiation experiments with aqueous suspensions that simulate marine aerosol particles. The increased release of soluble Fe(II) is attributed to a …

Go to article

Structure-Activity Studies Of Glycosphingolipids As Antigens Of Natural Killer T Cells, Randal Donald Goff Jul 2006

Structure-Activity Studies Of Glycosphingolipids As Antigens Of Natural Killer T Cells, Randal Donald Goff

Theses and Dissertations

Glycosphingolipids (GSLs), composed of a polar saccharide head and a lipophilic ceramide tail, are ubiquitous components of the plasma membrane of eukaryotic cells. They serve in many regulatory capacities and have antigenic properties towards natural killer T (NKT) cells of the innate immune system. Critical to the recognition of glycosylceramides by NKT cells are antigen presenting cells (APC), such as dendritic cells, which are responsible for binding, processing, and delivery of ligands to these lymphocytes. This event is mediated by CD1d, a major histocompatibility complex-like protein expressed on the surface of APCs, which binds GSL antigens by the ceramide moiety …

Go to article

48th Rocky Mountain Conference On Analytical Chemistry Jul 2006

48th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 48th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Breckenridge, Colorado, July 23-27, 2006.

Go to article

Comparison Of Protein Active Site Structures For Functional Annotation Of Proteins And Drug Design, Robert Powers, Jennifer C. Copeland, Katherine Germer, Kelly A. Mercier, Viswanathan Ramanathan, Peter Revesz Jul 2006

Comparison Of Protein Active Site Structures For Functional Annotation Of Proteins And Drug Design, Robert Powers, Jennifer C. Copeland, Katherine Germer, Kelly A. Mercier, Viswanathan Ramanathan, Peter Revesz

Robert Powers Publications

Rapid and accurate functional assignment of novel proteins is increasing in importance, given the completion of numerous genome sequencing projects and the vastly expanding list of unannotated proteins. Traditionally, global primary-sequence and structure comparisons have been used to determine putative function. These approaches, however, do not emphasize similarities in active site configurations that are fundamental to a protein’s activity and highly conserved relative to the global and more variable structural features. The Comparison of Protein Active Site Structures (CPASS) database and software enable the comparison of experimentally identified ligand-binding sites to infer biological function and aid in drug discovery. The …

Go to article

Accumulation Of Phycotoxins In The Mussel Mytilus Galloprovincialis From The Central Adriatic Sea, Maja Pavela-Vrančić, Ivana Ujević, Živana Ninčević Gladan, Ambrose Furey Jul 2006

Accumulation Of Phycotoxins In The Mussel Mytilus Galloprovincialis From The Central Adriatic Sea, Maja Pavela-Vrančić, Ivana Ujević, Živana Ninčević Gladan, Ambrose Furey

Physical Sciences Publications

Surveys of DSP (Diarrheic Shellfish Poisoning) toxin profiles in the mussel Mytilus galloprovincialis from coastal waters of the central Adriatic Sea, over the years 1995 to 2001, demonstrate that incidents of shellfish toxicity in this area are dominated by the occurrence of okadaic acid (OA) and a PTX derivative, 7-epi-pectenotoxin-2-seco acid (7-epi-PTX-2SA). Toxin composition and the relative ratio of toxic components in shellfish is in correlation with the occurrence of DSP producing organisms from the Dinophysis species along with Prorocentrum micans and Lingulodinium polyedrum. The occurrence of D. sacculus shortly before the appearance of OA in shellfish implicates its possible …

Go to article

The Effect Of Protein Dielectric Coefficient On The Ionic Selectivity Of A Calcium Channel, Douglas Henderson, Dezso Boda, Monika Valisko, Bob Eisenberg, Wolfgang Nonner, Dirk Gillespie Jul 2006

The Effect Of Protein Dielectric Coefficient On The Ionic Selectivity Of A Calcium Channel, Douglas Henderson, Dezso Boda, Monika Valisko, Bob Eisenberg, Wolfgang Nonner, Dirk Gillespie

Faculty Publications

Calcium-selective ion channels are known to have carboxylate-rich selectivity filters, a common motif that is primarily responsible for their high Ca2+ affinity. Different Ca2+ affinities ranging from micromolar (the L-type Ca channel) to millimolar (the ryanodine receptor channel) are closely related to the different physiological functions of these channels. To understand the physical mechanism for this range of affinities given similar amino acids in their selectivity filters, we use grand canonical Monte Carlo simulations to assess the binding of monovalent and divalent ions in the selectivity filter of a model Ca channel. We use a reduced model where the electrolyte …

Go to article

Dna-Templated Surface Alignment And Characterization Of Carbon Nanotubes., Huijun Xin Jul 2006

Dna-Templated Surface Alignment And Characterization Of Carbon Nanotubes., Huijun Xin

Theses and Dissertations

Carbon nanotubes are appealing materials for nanofabrication due to their unique properties and structures. However, for carbon nanotubes to be used in mass-fabricated devices, precise control of nanotube orientation and location on surfaces is critical. I have developed a technique to align single-walled carbon nanotubes (SWNTs) on surfaces from a droplet of nanotube suspension under gas flow. Fluid motion studies indicate that alignment is likely due to circulation of SWNTs in the droplet. My work provides a facile method for generating oriented nanotubes for nanodevice applications. I have also devised an approach for localizing SWNTs onto 1-pyrenemethylamine-decorated DNA on surfaces. …

Go to article

The Structural Integrity Of Anion Binding Exosite I Of Thrombin Is Required And Sufficient For Timely Cleavage And Activation Of Factor V And Factor Viii, Michael A. Bukys, Tivadar Orban, Paul Y. Kim, Daniel O. Beck, Michael E. Nesheim, Michael Kalafatis Jul 2006

The Structural Integrity Of Anion Binding Exosite I Of Thrombin Is Required And Sufficient For Timely Cleavage And Activation Of Factor V And Factor Viii, Michael A. Bukys, Tivadar Orban, Paul Y. Kim, Daniel O. Beck, Michael E. Nesheim, Michael Kalafatis

Chemistry Faculty Publications

Alpha-thrombin has two separate electropositive binding exosites (anion binding exosite I, ABE-I and anion binding exosite II, ABE-II) that are involved in substrate tethering necessary for efficient catalysis. Alpha-thrombin catalyzes the activation of factor V and factor VIII following discrete proteolytic cleavages. Requirement for both anion binding exosites of the enzyme has been suggested for the activation of both procofactors by alpha-thrombin. We have used plasma-derived alpha-thrombin, beta-thrombin (a thrombin molecule that has only ABE-II available), and a recombinant prothrombin molecule rMZ-II (R155A/R284A/R271A) that can only be cleaved at Arg(320) (resulting in an enzymatically active molecule that has only ABE-I …

Go to article

Enhanced Electrospray Ionization For Mass Spectrometry And Ion Mobility Spectrometry, Li Zhou Jul 2006

Enhanced Electrospray Ionization For Mass Spectrometry And Ion Mobility Spectrometry, Li Zhou

Theses and Dissertations

Electrospray ionization (ESI) has become one of the most commonly used ionization techniques for mass spectrometry (MS) and ion mobility spectrometry (IMS), and efforts continue to improve its performance. ESI-MS is most recognized for its wide application to biomacromolecules where high sensitivity is of paramount importance. However, the major limitation in sensitivity with ESI-MS is due to its low ion transmission efficiency from the ESI source into the sampling orifice and through any stages utilized for transfer of ions from atmosphere to vacuum in the MS. A series of atmospheric pressure ion focusing interfaces were designed and implemented to enhance …

Go to article

Electric Field Gradient Focusing-Uv Detection For Protein Analysis, Shu-Ling Lin Jul 2006

Electric Field Gradient Focusing-Uv Detection For Protein Analysis, Shu-Ling Lin

Theses and Dissertations

Electric field gradient focusing (EFGF) utilizes a hydrodynamic flow and an electric field gradient to focus and concentrate charged analytes and order them in a separation channel according to electrophoretic mobility. Elution can be achieved by decreasing the applied voltage or increasing the hydrodynamic flow. EFGF has the advantages of concentrating a large volume (100 micro-L) of target proteins without significant band broadening and simultaneously removing unwanted components from the sample. Two types of EFGF devices have been investigated to concentrate and separate proteins: a fiber-based EFGF device and a hydrogel-based EFGF device. Using fiber-based EFGF with UV detection, a …

Go to article

Investigation Of Ruthenium (Ii) Polypyridyl Dimers As Potential Chemotherapeutic Agents, Thamara K. Janaratne Jul 2006

Investigation Of Ruthenium (Ii) Polypyridyl Dimers As Potential Chemotherapeutic Agents, Thamara K. Janaratne

Chemistry & Biochemistry Dissertations - Archive

The exploration of transition metal complexes as chemotherapeutic agents is still a relatively unexplored but promising area of research. Chapter 1 highlights the most successful anticancer drugs and potential drugs based on metal complexes, with an emphasis of platinum and ruthenium complexes. In Chapter 2, the biological activity of a series of novel ruthenium dimers is investigated with special attention given to evaluating their potential as anticancer chemotherapeutic agents. A partial list of the compound prepared includes: [Ru(bpy)(CO)2}2tpphz]4+ (74+), [Ru(bpy)(CH3CN)2}2tpphz]4+ (84+),[Ru(bpy)(C2O4)}2tpphz] (9), [Ru(bpy)(CO)(Cl)}2tpphz]2+ (102+), [(bpy)2Ru(tpphz)Ru(bpy)2]4+ (114+), [(phen)2Ru(tpphz)Ru(phen)2]4+ (124+), [(phen)2Ru(tatpp)Ru(phen)2]4+ (Pp4+), [(phen)2Ru(tatpq)Ru(phen)2]4+ (Qp4+), [(bpy)2Ru(tatpp)Ru(bpy)2]4+ (Pb4+) and [(bpy)2Ru(tatpq)Ru(bpy)2]4+ (Qb4+). Systematic changes in …

Go to article

Formation Of Monofunctional Cisplatin-Dna Adducts In Carbonate Buffer, Alexandra Binter, Jerry Goodisman, James C. Dabrowiak Jul 2006

Formation Of Monofunctional Cisplatin-Dna Adducts In Carbonate Buffer, Alexandra Binter, Jerry Goodisman, James C. Dabrowiak

Chemistry - All Scholarship

Carbonate in its various forms is an important component in blood and the cytosol. Since, under conditions that simulate therapy, carbonate reacts with cisplatin to form carbonato complexes, one of which is taken up and/or modified by the cell [C.R. Centerwall, J. Goodisman, D.J. Kerwood, J. Am. Chem. Soc., 127 (2005) 12768–12769], cisplatin-carbonato complexes may be important in the mechanism of action of cisplatin. In this report we study the binding of cisplatin to pBR322 DNA in two different buffers, using gel electrophoresis. In 23.8 mM HEPES, N-(2-hydroxyethyl)-piperazine-N′-2-ethanesulfonic acid, 5 mM NaCl, pH 7.4 buffer, cisplatin produces …

Go to article

Numerical Simulation And Graphical Analysis Of In Vitro Benign Tumor Growth: Application Of Single-Particle State Bosonic Matter Equation With Length Scaling, Pradip K. Biswas, Jiansen Niu, Tobias Frederico, Valentin Gogonea Jul 2006

Numerical Simulation And Graphical Analysis Of In Vitro Benign Tumor Growth: Application Of Single-Particle State Bosonic Matter Equation With Length Scaling, Pradip K. Biswas, Jiansen Niu, Tobias Frederico, Valentin Gogonea

Chemistry Faculty Publications

We describe the application of a non-linear single-particle state bosonic condensate equation to simulate multicellular tumor growth by treating it as a coupling of two classical wave equations with real components. With one component representing the amplitude of the cells in their volume growth phase and the other representing the amplitude of the cells in their proliferation or mitosis phase, the two components of the coupled equation feed each other during the time evolution and are coupled together through diffusion and other linear and non-linear terms. The features of quiescent and necrotic cells, which result from poor nutrient diffusion into …

Go to article

Staphylococcus Aureus Helicase But Not Escherichia Coli Helicase Stimulates S. Aureus Primase Activity And Maintains Initiation Specificity, Scott A. Koepsell, Marilynn A. Larson, Mark A. Griep, Steven H. Hinrichs Jul 2006

Staphylococcus Aureus Helicase But Not Escherichia Coli Helicase Stimulates S. Aureus Primase Activity And Maintains Initiation Specificity, Scott A. Koepsell, Marilynn A. Larson, Mark A. Griep, Steven H. Hinrichs

Mark A. Griep Publications

Bacterial primases are essential for DNA replication due to their role in polymerizing the formation of short RNA primers repeatedly on the lagging-strand template and at least once on the leading-strand template. The ability of recombinant Staphylococcus aureus DnaG primase to utilize different single-stranded DNA templates was tested using oligonucleotides of the sequence 5’-CAGA (CA) 5 XYZ (CA) 3-3’, where XYZ represented the variable trinucleotide. These experiments demonstrated that S. aureus primase synthesized RNA primers predominately on templates containing 5’-d(CTA)-3’ or TTA and to a much lesser degree on GTA-containing templates, in contrast to results seen with the Escherichia …

Go to article

Model Studies Towards The Total Synthesis Of Lyconadin A Via An Acyl Radical Cascade Reaction, Koudi Zhu Jun 2006

Model Studies Towards The Total Synthesis Of Lyconadin A Via An Acyl Radical Cascade Reaction, Koudi Zhu

Theses and Dissertations

Lyconadin A is an alkaloid possessing a unique structure and antitumor activity. The total synthesis of Lyconadin A was proposed via an acyl radical cascade reaction. To investigate the possibility and stereoselectivity of the cascade cyclization, phenyl selenoester 16 was chosen as a model substrate to study the 7-exo-5-exo radical cyclization. A synthetic route to phenyl selenoester 16 was developed. The 7-exo-5-exo radical cyclization was found to occur with a high yield and excellent stereoselectivty. Attempts were also tried to synthesize another radical precursor 14 albeit with less success. A synthetic pathway to the synthesis of 14 as well as …

Go to article

The Importance Of The Strictly Conserved, C-Terminal Glycine Residue In Phosphoenolpyruvate Carboxylase For Overall Catalysis: Mutagenesis And Truncation Of Gly-961 In The Sorghum C4 Leaf Isoform, Wenxin Xu, Shaheen Ahmed, Hideaki Moriyama, Raymond Chollet Jun 2006

The Importance Of The Strictly Conserved, C-Terminal Glycine Residue In Phosphoenolpyruvate Carboxylase For Overall Catalysis: Mutagenesis And Truncation Of Gly-961 In The Sorghum C4 Leaf Isoform, Wenxin Xu, Shaheen Ahmed, Hideaki Moriyama, Raymond Chollet

Hideaki Moriyama Publications

Phosphoenolpyruvate carboxylase (PEPC) is a “multifaceted,” allosteric enzyme involved in C4 acid metabolism in green plants/microalgae and prokaryotes. Before the elucidation of the three-dimensional structures of maize C4 leaf and Escherichia coli PEPC, our truncation analysis of the sorghum C4 homologue revealed important roles for the enzyme’s C-terminal α-helix and its appended QNTG961 tetrapeptide in polypeptide stability and overall catalysis, respectively. Collectively, these functional and structural observations implicate the importance of the PEPC C-terminal tetrapeptide for both catalysis and negative allosteric regulation. We have now more finely dissected this element of PEPC structure-function by modification of the absolutely conserved …

Go to article

The Mechanism Of Assembly Of The G-Protein Beta Gamma Subunit Dimer By Ck2 Phosphorylated Phosducin-Like Protein And The Chaperonin Containing Tcp-1, Christine M. Baker Jun 2006

The Mechanism Of Assembly Of The G-Protein Beta Gamma Subunit Dimer By Ck2 Phosphorylated Phosducin-Like Protein And The Chaperonin Containing Tcp-1, Christine M. Baker

Theses and Dissertations

Phosducin-like protein (PhLP) binds G-protein beta gamma subunits and is thought to assist in assembly of the G-protein beta gamma dimer. Phosphorylation of PhLP at serine residues 18-20 by the casein kinase 2 (CK2) appears to play an essential role in this process. PhLP has also been shown to interact with the chaperonin containing TCP-1 (CCT) atop its apical domain, not entering the substrate folding cavity. However, the physiological role of the PhLP-CCT interaction in G-protein beta gamma dimer formation remains unclear. This study addresses the mechanism of G-protein beta gamma assembly by exploring the specific roles of CCT and …

Go to article

Fabrication Of Polymeric Microfluidic Devices For Protein Analysis, Jikun Liu Jun 2006

Fabrication Of Polymeric Microfluidic Devices For Protein Analysis, Jikun Liu

Theses and Dissertations

2-Bromoisobutyryl bromide was immobilized on poly(methyl methacrylate) (PMMA) substrates activated using an oxygen plasma. Atom-transfer radical polymerization was then performed to graft poly(ethylene glycol) (PEG) on the PMMA surface. PMMA micro capillary electrophoresis (µCE) devices made with the covalently modified surfaces exhibited substantially reduced electroosmotic flow and nonspecific adsorption of proteins. Both column efficiency and migration time reproducibility were one order of magnitude better with derivatized PMMA µCE devices compared to untreated versions. Fast, reproducible, and efficient separations of proteins and peptides were demonstrated using the PEG-grafted PMMA µCE chips. All analyses were completed in less than 60 seconds, and …

Go to article

(Review) Green Fluorescent Proteins, Marc Zimmer Jun 2006

(Review) Green Fluorescent Proteins, Marc Zimmer

Chemistry Faculty Publications

Reviews the book:Green Fluorescent Protein: Properties, Applications, and Protocols. Second Edition. Methods of Biochemical Analysis, Volume 47. Edited by Martin Chalfie and Steven R Kain.Green Fluorescent Protein: Properties, Applications, and Protocols. Second Edition. Methods of Biochemical Analysis, Volume 47. Edited by Martin Chalfie and Steven R Kain. Hoboken (New Jersey): Wiley-Interscience. $89.95. xv + 443 p + 24 pl; ill.; index. ISBN: 0–471–73682–1. 2006.

Go to article

Studies Toward The Enantioselective Total Synthesis Of The Martinella Alkaloids, Vivek Badarinarayana Jun 2006

Studies Toward The Enantioselective Total Synthesis Of The Martinella Alkaloids, Vivek Badarinarayana

Chemistry & Biochemistry Dissertations - Archive

This dissertation consists of two parts. The first part describes the enantioselective total synthesis of martinellic acid. The Martinella alkaloids have attracted considerable attention in the synthetic community over the past few years. This interest is due in large part to their unique structure and useful biological activity (bradykinin receptor antagonist). In model systems we have successfully used the [3+2] azomethine ylide-alkene cycloaddition to construct the heterocyclic core of these alkaloids. The enantioselective approach described herein also involves the azomethine ylide-alkene cycloaddition as a key step in the total synthesis. The pyrrolo[3,2-c]quinoline core of this alkaloid was constructed in an …

Go to article

Kinetics Of The Dna Polymerase Pyrococcus Kodakaraensis, Mark A. Griep, Casey A. Kotera, R.M. Nelson, Hendrik J. Viljoen Jun 2006

Kinetics Of The Dna Polymerase Pyrococcus Kodakaraensis, Mark A. Griep, Casey A. Kotera, R.M. Nelson, Hendrik J. Viljoen

Mark A. Griep Publications

The polymerase chain reaction is one of the most important reactions in molecular biology. Single stranded DNA is copied in a complex series of steps, at the core of which lies the action of the DNA polymerase. At each nucleotide along the template, the polymerase screens the dNTP pool until it finds the complementary dNTP. The insertion of each dNMP is a balance between high fidelity and rapid elongation. In this study the kinetics of the β type polymerase pyrococcus kodakaraensis (KOD) is analyzed. The kinetics is influenced by reaction conditions such as the dNTP pool composition and temperature. In …

Go to article

Molecular Characterization Of Wetland Soil Bacterial Community In Constructed Mesocosms, Ethan C. Bishop Jun 2006

Molecular Characterization Of Wetland Soil Bacterial Community In Constructed Mesocosms, Ethan C. Bishop

Theses and Dissertations

The use of wetlands to effectively remediate aquifers contaminated with chlorinated solvents is an emerging technique, which shows high promise. In order to better understand this process and test its legitimacy, a treatment wetland was constructed at Wright-Patterson AFB, Dayton, Ohio and, in a joint effort with Wright State University (WSU), has previously shown the effective removal of PCE. The purpose of this research was to characterize the soil bacterial community, pre-PCE injection, among three wetland plant species from the sedge family (Cyperaceae) within constructed wetland mesocosms and to identify any bacterial dominance. Carex comosa, Scirpus atrovirens, and Eleocharis erythropoda …

Go to article

Gas Chromatography On Self Assembled Single Walled Carbon Nanotubes, Mahesh Kumar Karwa May 2006

Gas Chromatography On Self Assembled Single Walled Carbon Nanotubes, Mahesh Kumar Karwa

Dissertations

Carbon nanotubes (CNTs) are nano-sized carbon-based sorbents, which have high surface area, large aspect ratio, can be self-assembled and are known to be stable at high temperatures. It is therefore conceivable that separation techniques, such as, gas chromatography (GC) can benefit from their unique properties and nano-scale interactions. Self-assembly, in-contrast to packing these materials in a tube, prevents them from agglomeration and thus facilitates in retaining their nano-characteristics. In this research, novel substrates, such as, steel tubings, on a scaled-up level have been explored for the self-assembly process of CNTs, for applications such as gas chromatography, where the CNTs served …

Go to article

Evidence Of Hollow Golden Cages, Satya S. Bulusu, Xi Li, Lai-Sheng Wang, Xiao Cheng Zeng May 2006

Evidence Of Hollow Golden Cages, Satya S. Bulusu, Xi Li, Lai-Sheng Wang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The fullerenes are the first “free-standing” elemental hollow cages identified by spectroscopy experiments and synthesized in the bulk. Here, we report experimental and theoretical evidence of hollow cages consisting of pure metal atoms, Au–n (n = 16–18); to our knowledge, free-standing metal hollow cages have not been previously detected in the laboratory. These hollow golden cages (“bucky gold”) have an average diameter >5.5 Å, which can easily accommodate one guest atom inside.

Go to article

Molecular Dynamics Of Polystyrene Solutions In Microwave Fields, Mark J. Purdue, James M. D. Macelroy, D. F. O'Shea, Macduff O. Okuom, Frank D. Blum May 2006

Molecular Dynamics Of Polystyrene Solutions In Microwave Fields, Mark J. Purdue, James M. D. Macelroy, D. F. O'Shea, Macduff O. Okuom, Frank D. Blum

Chemistry Faculty Research & Creative Works

Equilibrium and nonequilibrium molecular dynamics simulation techniques were used to assess the influence of an applied microwave field on the dynamics of methylamine-methanol and methylamine-dimethylformamide (DMF) solutions bound within atactic polystyrene over a range of polymer densities from 35 to 96 wt % polymer. Atomistically detailed systems were studied, ranging from 3000 to 10 644 particles, using previously established potential models. Structural and dynamical properties were determined in the canonical (NVT) ensemble at 298 K. The simulated DMF self-diffusion coefficients in polystyrene solutions were compared with the zero-field experimental results established with pulsed-gradient spin-echo NMR spectrometry. A simulated external microwave …

Go to article

An Investigation Into The Antifungal Activities Of N-Thiolated Beta- Lactams Against Selected Candida Species, Marci Culbreath May 2006

An Investigation Into The Antifungal Activities Of N-Thiolated Beta- Lactams Against Selected Candida Species, Marci Culbreath

USF Tampa Graduate Theses and Dissertations

β-lactam antibiotics have long been a reliable course of treatment for bacterial infections. However, with recent increases in resistance and rising populations of immunocompromised patients new β-lactams have been synthesized and tested. The Turos laboratory has recently discovered novel β-lactams that have a mode of action distinct from penicillin and other β-lactam antibiotics as cell lysis is not observed. In the current investigations, these compounds are shown to also have antifungal properties. The rising incidence and prevalence of invasive fungal infections has become an increasing concern. The most common fungal pathogens involved in these infections are species in the genus …

Go to article

First Prev Next Last