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 11911 - 11940 of 15551

Full-Text Articles in Entire DC Network

Understanding The Selective Detection Of Homocysteine And Studies Toward The Synthesis Of Vinigrol, Dong Wang Jan 2011

Understanding The Selective Detection Of Homocysteine And Studies Toward The Synthesis Of Vinigrol, Dong Wang

LSU Doctoral Dissertations

The first part of the work is dedicated to the selective detection of Homocysteine (Hcy). In order to better understand this colorimetric detection method, a thermodynamic model for the pH dependence of the effective reduction potential of Hcy derived á-carbon radicals has been proposed. And using viologen indicators of varying reduction potentials, we demonstrate that colorimetric changes occur at experimental pH values consistent with the model. The one-carbon bridge stereochemistry of bicyclo[3.3.1]nonane framework is critical to make the third ring of the tricyclic precursor of vinigrol. We studied this stereochemistry carefully and found that the major diastereomer formed from Robinson …

Go to article

Localized Surface Plasmon Resonance Of Single Silver Nanoparticles Studied By Dark-Field Optical Microscopy And Spectroscopy, Wei Cao, Tao Huang, Xiao-Hong Nancy Xu, Hani E. Elsayed-Ali Jan 2011

Localized Surface Plasmon Resonance Of Single Silver Nanoparticles Studied By Dark-Field Optical Microscopy And Spectroscopy, Wei Cao, Tao Huang, Xiao-Hong Nancy Xu, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Localized surface plasmon resonance (LSPR) of Ag nanoparticles (NPs) with different shapes and disk-shaped Ag NP pairs with varying interparticle distance is studied using dark-field optical microscopy and spectroscopy (DFOMS). Disk-, square-, and triangular-shaped Ag NPs were fabricated on indium tin oxide-coated glass substrates by electron beam lithography. The LSPR spectra collected from single Ag NPs within 5×5 arrays using DFOMS exhibited pronounced redshifts as the NP shape changed from disk to square and to triangular. The shape-dependent experimental LSPR spectra are in good agreement with simulations using the discrete dipole approximation model, although there are small deviations in the …

Go to article

Spectroscopic Study Of New Sensors For Organophosphates, Metals, And Cyanide Based On Rhodamine And Cholic Acid Derivatives, Arambe Gedara Aruna Weerasinghe Jan 2011

Spectroscopic Study Of New Sensors For Organophosphates, Metals, And Cyanide Based On Rhodamine And Cholic Acid Derivatives, Arambe Gedara Aruna Weerasinghe

Dissertations

Despite the increasing interest in developing sensors for nerve gas agents, efficient detection remains challenging. Among the various sensors developed so far, fluorescence sensors play an important role due to their simplicity. We developed six new rhodamine-based compounds that can be used as fluorescent turn-on sensors. Compound 1 and 3 gave high fluorescent enhancement with diethyl chlorophosphate (DCP) compared to the other compounds. Very high selectivity and sensitivity were observed as these compounds did not show significant fluorescent enhancement with dimethyl methylphosphonate (DMMP), HC1 and transition metal ions. The potential sensor can be used in solution as well as on …

Go to article

Glucosamine-Induced Insulin Resistance In Primary Rat Hepatocytes And The Role Of Selenium As An Insulin Mimetic, Sandhya N. Adiyodi Veetil Jan 2011

Glucosamine-Induced Insulin Resistance In Primary Rat Hepatocytes And The Role Of Selenium As An Insulin Mimetic, Sandhya N. Adiyodi Veetil

Dissertations

Type 2 diabetes is mediated by insulin resistance, the inability of insulin to elicit a normal biological response in insulin responsive tissues. Several cellular models have been utilized to determine the mechanism of induction of insulin resistance but questions remain unanswered. One model, implicates the products of the Hexosamine Biosynthetic Pathway (HBP) in the induction of insulin resistance under hyperglycemia. The major end product of HBP, UDP-GlcNAc, is the substrate for O-GlcNAc transferase, an enzyme that catalyzes the O-GlcNAcylation of numerous proteins. This modification may play a role in induction of insulin resistance and thus needs to be evaluated in …

Go to article

Design And Synthesis Of Beta-Hairpin Peptidomimetics For Modulating Integrin Mediated Cell Adhesion, Abeta Fibrillogenesis And P53-Mdm2 Protein-Protein Interactions, Priyesh Jain Dec 2010

Design And Synthesis Of Beta-Hairpin Peptidomimetics For Modulating Integrin Mediated Cell Adhesion, Abeta Fibrillogenesis And P53-Mdm2 Protein-Protein Interactions, Priyesh Jain

USF Tampa Graduate Theses and Dissertations

Inhibiting therapeutically important protein-protein interactions has been a tremendous challenge for medicinal chemists. The folded 3D structures of peptides and proteins, mainly comprise secondary structural elements i.e α-helices and β-sheet have created an opportunity to design small molecules and peptidomimetic inhibitors of protein-protein interaction (PPI). Hence, information about the formation and stabilization of these secondary structures is vital for designing future drugs. In this dissertation, several cyclic beta-hairpin peptidomimetics that mimic the recognition surface have been designed and synthesized as inhibitors for different targets such as integrin mediated extracellular matrix -cell adhesion in multiple myeloma, p53-MDM2 PPI, amyloid beta fibrillogenesis …

Go to article

Strategies To Resolve The Three-Dimensional Structure Of The Genome Of Small Single-Stranded Icosahedral Viruses, Eduardo Sanz Garcia Dec 2010

Strategies To Resolve The Three-Dimensional Structure Of The Genome Of Small Single-Stranded Icosahedral Viruses, Eduardo Sanz Garcia

Theses and Dissertations

The aim of this study is the three-dimensional structural characterization of the genome packaging inside viral capsids via cryo-electron microscopy and three-dimensional reconstruction. The genome of some single-stranded viruses can be densely packaged within their capsid shells. Several stretches of the genome are known to adopt stable secondary structures, however, to date, little is known about the three-dimensional organization of the genome inside their capsid shells. Two techniques have been developed to facilitate the structural elucidation of genome packaging: the asymmetric random-model method, and the symmetry-mismatch, random model method. Both techniques were successfully tested with model and experimental data. The …

Go to article

Conjugate Additions And Transposition Of The Allylic Alcohols Of Enol Ethers Of 1, 2-Cyclohexanedione., Barnabas Otoo Dec 2010

Conjugate Additions And Transposition Of The Allylic Alcohols Of Enol Ethers Of 1, 2-Cyclohexanedione., Barnabas Otoo

Electronic Theses and Dissertations

A variety of protected enolic forms of 1, 2-cyclohexanedione was prepared as substrates for conjugate addition studies using organocopper reagents. The sequence involved the enol ether preparation via the enolate, alkylation with an organometalic reagent, and oxidative rearrangement with pyridinium chlorochromate followed by the conjugate addition reactions. Protection of 1, 2-cyclohexanedione was achieved by reacting with chloro tert-butyldimethyl silane and subjected to alkylation. Steric problems were encountered and so an alternative protective group the methoxymethyl acetal was prepared and studied. Alkylation of these derivatives was successful; however, the oxidation was problematic and although evidence for rearrangement was observed in one …

Go to article

The Correlation Of The Concentration Of Selected Metals Determined In Water And Fish Samples From A Public Pond., Paula Kay Edwards Dec 2010

The Correlation Of The Concentration Of Selected Metals Determined In Water And Fish Samples From A Public Pond., Paula Kay Edwards

Electronic Theses and Dissertations

The concentrations of heavy metals (Cd, Cu, Fe, Ni, Pb, Zn) were measured in water, and fish samples caught from the pond at Fishery Park in Unicoi County, TN. The water samples were collected once a week for 8 weeks. The amounts of metals in the muscle tissues, gill, and liver of the two fish species were measured. This was to determine if any correlation exists between the metal contents in water and those in the fish samples. The concentration ranges for the heavy metals found in the water samples are as follows: Zn 0.04-0.13; Cu, 0.00-0.00; Pb, 0.00-0.59; Cd, …

Go to article

Extraction And Determination Of A Selected Polyphenol From Selected Red And Black Grapes By High Performance Liquid Chromatography., Summer Nicole Niles Dec 2010

Extraction And Determination Of A Selected Polyphenol From Selected Red And Black Grapes By High Performance Liquid Chromatography., Summer Nicole Niles

Undergraduate Honors Theses

Polyphenols are a group of compounds found naturally in plants and they provide much of the flavor, color, and taste to fruits, vegetables, seeds, and other parts of the plants They also act as antioxidants which provide numerous health benefits by protecting cells against damage caused by free radicals. Their antibacterial, anti-inflammatory and anti-allergenic properties have also contributed to the prevention of degenerative diseases, such as cardiovascular diseases and cancers by slowing the rate of oxidative stress on cells. This study was aimed at the identification and quantitation of a specific polyphenol, quercetin, found in grapes commonly purchased at grocery …

Go to article

Role Of Amyloid Beta Assembly State In The Human Immune Response, Deepa Viswanathan Dec 2010

Role Of Amyloid Beta Assembly State In The Human Immune Response, Deepa Viswanathan

Dissertations

Alzheimer’s disease (AD) is a slowly progressing neurodegenerative disease that leads to dementia. Histopathological hallmarks that characterize AD are senile plaques formed by extracellular deposition of Amyloid beta (Aβ) peptide and intracellular aggregates of hyperphosphorylated tau protein. The plaques, which are found in the brain parenchyma, comprise both 40 and 42 residue Aβ. Aggregation of Aβ is an established pathogenic mechanism in AD, but little is known about the initiation of this process in vivo. Several studies have revealed significant inflammatory markers such as activated microglia and cytokines surrounding the plaques. Plaques are a hallmark of AD, but they are …

Go to article

Chemical Vapor Deposition Of Silanes And Patterning On Silicon, Feng Zhang Dec 2010

Chemical Vapor Deposition Of Silanes And Patterning On Silicon, Feng Zhang

Theses and Dissertations

Self assembled monolayers (SAMs) are widely used for surface modification. Alkylsilane monolayers are one of the most widely deposited and studied SAMs. My work focuses on the preparation, patterning, and application of alkysilane monolayers. 3-aminopropyltriethoxysilane (APTES) is one of the most popular silanes used to make active surfaces for surface modification. To possibly improve the surface physical properties and increase options for processing this material, I prepared and studied a series of amino silane surfaces on silicon/silicon dioxide from APTES and two other related silanes by chemical vapor deposition (CVD). I also explored CVD of 3-mercaptopropyltrimethoxysilane on silicon and quartz. …

Go to article

Biomarkers Of Mild Cognitive Impairment And Alzheimer's Disease, Mark A. Lovell, Bert C. Lynn Dec 2010

Biomarkers Of Mild Cognitive Impairment And Alzheimer's Disease, Mark A. Lovell, Bert C. Lynn

Chemistry Faculty Patents

A method for quantifying a neurodegenerative disorder in a patient that includes obtaining a fluid sample from the subject; measuring a protein biomarker complex in said fluid sample and correlating the measurement with mild cognitive impairment or Alzheimer's disease status. The biomarkers include those that comprise at least one of a transthyretin protein and/or a prostaglandin-H2 D-isomerase protein, and at least one second, different protein selected from a transthyretin, prostaglandin-H2 D-isomerase, beta-2-microglobulin, cystatin C, superoxide dismutase [Cu—Zn], plasma retinol-binding protein, phosphatidylethanolamine-binding protein, carbonic anhydrase 2, prostaglandin-H2 D-isomerase, and/or serotransferrin protein.

Go to article

Superhydrophobic Thin Films Fabricated By Reactive Layer-By-Layer Assembly Of Azlactone-Functionalized Polymers, Maren E. Buck, Sarina C. Schwartz, David M. Lynn Dec 2010

Superhydrophobic Thin Films Fabricated By Reactive Layer-By-Layer Assembly Of Azlactone-Functionalized Polymers, Maren E. Buck, Sarina C. Schwartz, David M. Lynn

Chemistry: Faculty Publications

We report an approach to the fabrication of superhydrophobic thin films that is based on the "reactive" layer-by-layer assembly of azlactone-containing polymer multilayers. We demonstrate that films fabricated from alternating layers of the azlactone functionalized polymer poly(2-vinyl- 4,4-dimethylazlactone) (PVDMA) and poly(ethyleneimine) (PEI) exhibit micro- and nanoscale surface features that result in water contact angles in excess of 150°. Our results reveal that the formation of these surface features is (i) dependent upon film thickness (i.e., the number of layers of PEI and PVDMA deposited) and (ii) that it is influenced strongly by the presence (or absence) of cyclic azlactone-functionalized oligomers …

Go to article

Isomer-Dependent Adsorption And Release Of Cis- And Trans-Platin Anticancer Drugs By Mesopomus Silica Nanoparticles, Zhimin Tao, Youwei Xie, Jerry Goodisman, Tewodros Asefa Dec 2010

Isomer-Dependent Adsorption And Release Of Cis- And Trans-Platin Anticancer Drugs By Mesopomus Silica Nanoparticles, Zhimin Tao, Youwei Xie, Jerry Goodisman, Tewodros Asefa

Chemistry - All Scholarship

We report on adsorption and release of the anticancer drugs cisplatin and transplatin from mesoporous silica nanomaterials, emphasizing the differences between cisplatin and its much less toxic isomer. Two types of particles, M.CM-41 and SBA-IS, were used, either as just synthesized or after calcination to remove the templates. The particles were characterized by TEM, nitrogen physisorption, and elemental analysis. The UV-vis spectra of cisplatin and transplatin were obtained and the intensities of several bands (205-210 nm, 210-220 nm, 220-235 nm, and 300-330 nm) were found proportional to drug concentrations, allowing their use for measuring drug concentration. To evaluate drug adsorption …

Go to article

Activation Of Propargylic Alcohols By Piano-Stool Ruthenium Complexes Bearing Phosphoramidite Ligands, Stephen Andrew Costin Dec 2010

Activation Of Propargylic Alcohols By Piano-Stool Ruthenium Complexes Bearing Phosphoramidite Ligands, Stephen Andrew Costin

Dissertations

Various piano-stool ruthenium complexes bearing phosphoramidite ligands have been synthesized and characterized spectroscopically and in some cases structurally. Reaction of phosphoramidite ligands with an appropriate metal precursor gives new piano-stool ruthenium complexes [RuCl(L)(arene)(phosphoramidite)], where L = Cl, PPh3, or others. The novel complexes are tested for their ability to activate propargylic alcohols catalytically as well as stoichiometrically. Specifically, catalytic substitution of propargylic alcohols via allenylidene intermediates is envisioned. Stoichiometric reactions designed to form stable, isolable allenylidenes are sought as well. h6-p-cymene complexes of the type [RuCl2(h6-p-cymene)(phosphoramidite)] activate propargylic alcohols in the reaction with carboxylic acids to form b-oxo esters. The …

Go to article

Ua1b1/2 L.Y. Lancaster Lecture Series, Wku Archives Dec 2010

Ua1b1/2 L.Y. Lancaster Lecture Series, Wku Archives

WKU Archives Collection Inventories

Records regarding the L.Y. Lancaster Lecture Series.

Go to article

Hybrid Micro-/Nanogels For Optical Sensing And Intracellular Imaging, Weitai Wu, Shuiqin Zhou Dec 2010

Hybrid Micro-/Nanogels For Optical Sensing And Intracellular Imaging, Weitai Wu, Shuiqin Zhou

Publications and Research

Hybrid micro-/nanogels are playing an increasing important part in a diverse range of applications, due to their tunable dimensions, large surface area, stable interior network structure, and a very short response time. We review recent advances and challenges in the developments of hybrid micro-/nanogels toward applications for optical sensing of pH, temperature, glucose, ions, and other species as well as for intracellular imaging. Due to their unique advantages, hybrid micro-/nanogels as optical probes are attracting substantial interests for continuous monitoring of chemical parameters in complex samples such as blood and bioreactor fluids, in chemical research and industry, and in food …

Go to article

Direct Patterning Of Silanized-Biomolecules On Semiconductor Surfaces, Dorjderem Nyamjav, Richard C. Holz Dec 2010

Direct Patterning Of Silanized-Biomolecules On Semiconductor Surfaces, Dorjderem Nyamjav, Richard C. Holz

Chemistry Faculty Research and Publications

A novel approach to pattern silanized-biomolecules directly onto glass (SiOx) substrates via Dip-Pen nanolithography (DPN) and microcontact printing (μCP) is presented. Subsequent hybridization reactions of DPN patterned silanized-DNA with its complementary strands provide “proof-of-concept” that the patterned oligonucleotides maintain their biological activities. The fabrication strategy does not require premodification of substrates and offers a cheap and robust way to immobilize molecules on electronically important semiconductor surfaces.

Go to article

Dual Inhibition Of Sodium-Mediated Proton And Calcium Efflux Triggers Non-Apoptotic Cell Death In Malignant Gliomas, William Harley, Candace Floyd, Tamara Dunn, Xiao-Dong Zhang, Tsung-Yu Chen, Manu Hegde, Hasan Palandoken, Michael H. Nantz, Leonardo Leon, K.L. Carraway Iii, Bruce Lyeth, Fredric A. Gorin Dec 2010

Dual Inhibition Of Sodium-Mediated Proton And Calcium Efflux Triggers Non-Apoptotic Cell Death In Malignant Gliomas, William Harley, Candace Floyd, Tamara Dunn, Xiao-Dong Zhang, Tsung-Yu Chen, Manu Hegde, Hasan Palandoken, Michael H. Nantz, Leonardo Leon, K.L. Carraway Iii, Bruce Lyeth, Fredric A. Gorin

Chemistry and Biochemistry

Malignant glioma cells maintain an elevated intracellular pH (pHi) within hypoxic–ischemic tumormicroenvironments through persistent activation of sodium–proton transport (McLean et al., 2000). Amiloride has been reported to selectively kill human malignant glioma cell lines but not primary astrocytes (Hegde et al., 2004). While amiloride reduces pHi of malignant gliomas by inhibiting isoform 1 of sodium–proton exchange (NHE1), direct acidification was shown to be cytostatic rather than cytotoxic. At cytotoxic concentrations, amiloride has multiple drug targets including inhibition of NHE1 and sodium–calciumexchange. Amiloride's glioma cytotoxicity can be explained, at least in part, by dual inhibition of NHE1 and …

Go to article

Measurements Of Gas‐Phase Inorganic And Organic Acids From Biomass Fires By Negative‐Ion Proton‐Transfer Chemical‐Ionization Mass Spectrometry, P. Veres, James M. Roberts, I. R. Burling, C. Warneke, Joost De Gouw, Robert J. Yokelson Dec 2010

Measurements Of Gas‐Phase Inorganic And Organic Acids From Biomass Fires By Negative‐Ion Proton‐Transfer Chemical‐Ionization Mass Spectrometry, P. Veres, James M. Roberts, I. R. Burling, C. Warneke, Joost De Gouw, Robert J. Yokelson

Chemistry and Biochemistry Faculty Publications

[1] Emissions from 34 laboratory biomass fires were investigated at the combustion facility of the U.S. Department of Agriculture Fire Sciences Laboratory in Missoula, Montana. Gas-phase organic and inorganic acids were quantified using negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS), open-path Fourier transform infrared spectroscopy (OP-FTIR), and proton-transfer-reaction mass spectrometry (PTR-MS). NI-PT-CIMS is a novel technique that measures the mass-to-charge ratio (m/z) of ions generated from reactions of acetate (CH3C(O)O−) ions with inorganic and organic acids. The emission ratios for various important reactive acids with respect to CO were determined. Emission ratios for isocyanic acid (HNCO), 1,2 …

Go to article

Investigation Of Volatile Products From Wood Pyrolysis, Prabhavathi Gade Dec 2010

Investigation Of Volatile Products From Wood Pyrolysis, Prabhavathi Gade

Masters Theses & Specialist Projects

In this research we are following the thermo-chemical degradation of wood in the absence of oxygen. The objectives are to evaluate the influence of heating rates on pyrolysis products obtained from wood pyrolysis and to evaluate the influence of acid pre-treatment on pyrolysis products. Depending on the wood heating rates, pyrolysis can be categorized as Flash pyrolysis, Fast pyrolysis, and Slow pyrolysis. We have evaluated the volatile products obtained at different heating rates and the volatile products obtained from sulfuric acid pre-treatment by using gas chromatography- mass spectrometry (GC-MS). We have also performed thermo-gravimetric analysis (TGA) of raw wood samples …

Go to article

Quantum Chemical Studies Of Nucleic Acids: Can We Construct A Bridge To The Rna Structural Biology And Bioinformatics Communities?, Jiri Sponer,, Judit Sponer, Anton I. Petrov, Neocles B. Leontis Dec 2010

Quantum Chemical Studies Of Nucleic Acids: Can We Construct A Bridge To The Rna Structural Biology And Bioinformatics Communities?, Jiri Sponer,, Judit Sponer, Anton I. Petrov, Neocles B. Leontis

Chemistry Faculty Publications

In this feature article we provide a side-by-side introduction for two research fields quantum chemical calculations of molecular interaction in nucleic acids and RNA structural bioinformatics Our main aim is to demonstrate that these research areas while largely separated in contemporary literature have substantial potential to complement each other that could significantly contribute to our understanding of the exciting world of nucleic acids We identify research questions amenable to the combined application of modern ab initio methods and bioinformatics analysis of experimental structures while also assessing the limitations of these approaches The ultimate aim is to attain valuable physicochemical insights …

Go to article

Two-Phase Partitioning System Using Elvax 40w Polymer For The Biodegradation Of Aqueous Phenols, Amit Suresh Ghode Dec 2010

Two-Phase Partitioning System Using Elvax 40w Polymer For The Biodegradation Of Aqueous Phenols, Amit Suresh Ghode

Masters Theses & Specialist Projects

A solid-liquid two phase partitioning system (TPPS) is a new technology platform for destroying toxic organic compounds. TPPS have traditionally been operated by using an immiscible organic phase which partitions organic compounds into the aqueous phase. TPPS using an immiscible organic phase suffers from several limitations such as the organic phase could be biodegradable and hence only certain compatible microbial strains could be used. This therefore, eliminates the desired use of mixed microbial populations for efficient degradation. A solid-liquid two phase partitioning system, in which solid polymeric beads replace liquid organic phase, appears to have benefits over the traditional liquid-liquid …

Go to article

Ultrasonic Activation Of Triacetone Triperoxide, Latravia R. Dobson Dec 2010

Ultrasonic Activation Of Triacetone Triperoxide, Latravia R. Dobson

Department of Chemistry: Dissertations, Theses, and Student Research

Triacetone triperoxide (TATP) is an organic peroxide that has received widespread attention in recent years. TATP is a ketone peroxide with a high active oxygen content. It is relatively shock sensitive, with explosive decomposition easily initiated, and is therefore considered a primary explosive. However, TATP is also a powerful explosive possessing about 83 % of the power of TNT. TATP can be prepared quickly and easily from inexpensive household chemicals in the absence of any specialized facilities, making it the explosive of choice for modern day terrorists. TATP poses a major challenge for security and law enforcement services around the …

Go to article

I, A New Synthetic Approach To The Synthesis Of N-(Phosphonoacetyl)-L-Ornithine. Ii, The Influence Of Pyridine On The Ozonolysis Of Alkenes, Bradley M. Johnson Dec 2010

I, A New Synthetic Approach To The Synthesis Of N-(Phosphonoacetyl)-L-Ornithine. Ii, The Influence Of Pyridine On The Ozonolysis Of Alkenes, Bradley M. Johnson

Department of Chemistry: Dissertations, Theses, and Student Research

Part I. The use of chemical inhibitors to manipulate the level of amino acids in cells has proven to be invaluable in the mechanistic study of gene expression in bacteria and fungi. Here we present a new approach to the synthesis of δ‐N‐ (phosphonoacetyl)‐L‐ornithine (PALO), a potent ornithine transcarbamylase inhibitor, using a new amino acid protecting group, 9‐borabicyclononane (9‐BBN). Starting from commercially available reagents and utilizing mild reaction conditions, we were able to form PALO in fewer synthetic steps and in greater yields than previous attempts.

Part II. Ozonolysis is widely used to transform alkenes into oxygen‐rich functional groups (e.g.– …

Go to article

Kinetic, Mechanistic, And Structural Investigation Of Features Controlling Stereoselectivity Of (R)- And (S)-Hydroxypropyl Com Dehydrogenases From Xanthobacter Autrophicus Strain Py2, Dariusz Adam Sliwa Dec 2010

Kinetic, Mechanistic, And Structural Investigation Of Features Controlling Stereoselectivity Of (R)- And (S)-Hydroxypropyl Com Dehydrogenases From Xanthobacter Autrophicus Strain Py2, Dariusz Adam Sliwa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Enantiopure alcohols are valuable intermediates in fine organic synthesis, in particular for preparation of biologically active compounds. The necessity of preparing single enantiomer drugs in an optically pure form has triggered much research, especially in the pharmaceutical industry. The biocatalytical production of chiral alcohols by alcohol dehydrogenase enzymes is characterized by the asymmetric reduction of the corresponding ketones, usually with high degree of stereoselectivity. The commercial value of the enzymes as stereoselective biocatalysts has been a significant driving force in understanding features that control their mechanism of catalysis and stereoselectivity. This work focuses on two enantiocomplementary dehydrogenase enzymes ((R …

Go to article

Folate Receptor-Targeted Delivery Of Small Interfering Rna To Cancer Cells, Yilin Zhang Dec 2010

Folate Receptor-Targeted Delivery Of Small Interfering Rna To Cancer Cells, Yilin Zhang

Dissertations

The vitamin folic acid (folate, FA) has been extensively explored as a targeting ligand to deliver a variety of diagnostic/prognostic/therapeutic agents into various tumors through the assistance of its receptor – the folate receptor (FR). FR is over-expressed in many types of human cancer and can mediate internalization of FA-conjugates through an endocytic pathway. The discovery of small interfering RNA (siRNA), which is cable of inducing potent gene silencing in a sequence-specific manner, provides an excellent molecular tool to suppress aberrant gene expression in malignancies, and therefore siRNA has the potential to revolutionize cancer therapeutics. Towards the goal of developing …

Go to article

Electrochemical Investigation Of Azurin Thermodynamic And Adsorption Properties At Monolayer-Protected Cluster Film Assemblies – Evidence For A More Homogeneous Adsorption Interface, Tran Doan, Morgan Lynn Vargo, John K. Gerig, Chris P. Gulka, Matthew L. Trawick, Jonathan D. Dattelbaum, Michael C. Leopold Dec 2010

Electrochemical Investigation Of Azurin Thermodynamic And Adsorption Properties At Monolayer-Protected Cluster Film Assemblies – Evidence For A More Homogeneous Adsorption Interface, Tran Doan, Morgan Lynn Vargo, John K. Gerig, Chris P. Gulka, Matthew L. Trawick, Jonathan D. Dattelbaum, Michael C. Leopold

Chemistry Faculty Publications

Thermodynamic and adsorption properties of protein monolayer electrochemistry (PME) are examined for Pseudomonas aeruginosa azurin (AZ) immobilized at an electrode modified with a networked film of monolayer-protected clusters (MPCs) to assess if nanoparticle films of this nature offer a more homogeneous adsorption interface compared to traditional self-assembled monolayer (SAM) modified electrodes. Specifically, electrochemistry is used to assess properties of surface coverage, formal potential, peak broadening, and electron transfer (ET) kinetics as a function of film thickness. The modification of a surface with dithiol-linked films of MPCs (Au225C675) provides a more uniform binding interface for AZ that results in voltammetry with …

Go to article

Spectral Reflectance As An Indicator Of Foliar Concentrations Of Arsenic In Common Sunflower (Helianthus Annuus), Yuridia Patricia Peralta De Gandy Dec 2010

Spectral Reflectance As An Indicator Of Foliar Concentrations Of Arsenic In Common Sunflower (Helianthus Annuus), Yuridia Patricia Peralta De Gandy

Theses and Dissertations - UTB/UTPA

Studies were conducted to investigate the use of spectral reflectance by foliage of common sunflower as a potential indicator of arsenic contamination of soil. Germination method was developed for sunflower seeds, and cohorts of sunflower seedlings in hydroponic tanks were established. The cohorts were exposed to 0 ppm, 5 ppm, 7.5 ppm, and 10 ppm treatments of As (V) and reflectance measurements of foliage were collected using a spectroradiometer during two experiments.Results demonstrated the feasibility of using spectral reflectance by foliage of common sunflower as a potential indicator of arsenic contamination. In both experiments, arsenic concentrations in leaf tissues were …

Go to article

High Flow Air Sampling For Field Detection Using Gas Chromatography-Mass Spectrometry, Jacolin Ann Murray Dec 2010

High Flow Air Sampling For Field Detection Using Gas Chromatography-Mass Spectrometry, Jacolin Ann Murray

Theses and Dissertations

The ability to rapidly detect and identify hazardous analytes in the field has become increasingly important. One of the most important analytical detection methods in the field is gas chromatography-mass spectrometry (GC-MS). In this work, a hand-portable GC-MS system is described that contains a miniature toroidal ion trap mass analyzer and a low thermal mass GC. The system is self-contained within the dimensions of 47 x 36 x 18 cm and weighs less than 13 kg. Because the instrument has a small footprint, it was used as the detector for an automated near-real-time permeation testing system. In permeation testing, materials …

Go to article

First Prev Next Last