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2010

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Articles 571 - 600 of 950

Full-Text Articles in Chemistry

Process For Preparation Of Conducting Polymers, Reuben D. Rieke Jan 2010

Process For Preparation Of Conducting Polymers, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Methods of preparing conducting polymers and the conductive polymers prepared therefrom are provided. The method includes a) combining a monomer-metal complex together with a manganese (II) halide to provide a monomer-manga nese complex, and b) combining the monomer-manganese complex together with a metal catalyst to provide the conductive polymer. Electronic devices can be made using the polymers prepared as described herein.

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Routes To Acylated Sydnones Utilizing Microwave Chemistry, Amber C. Rumple Jan 2010

Routes To Acylated Sydnones Utilizing Microwave Chemistry, Amber C. Rumple

Browse all Theses and Dissertations

In the present work, microwave chemistry was utilized to improve and optimize two methods for the acylation of sydnones. Whereas before, 4-acyl-3-arylsydnones could be synthesized by the use of Friedel-Crafts reactions utilizing either Montmorillonite K-10 or bismuth(III) triflate/lithium perchlorate as catalysts in moderate to good yields after long reaction times, with the introduction of microwave chemistry 4-acyl-3-arylsydnones can be synthesized in good to excellent yields in much shorter times. A previous method using Montmorillonite K-10 allowed for a variety of 4-acetyl-3-arylsydnones to be synthesized thermally in moderate to good yields after at least 24 hours. This method was extended in …

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Tuning The Magnetic And Electronic Properties Of Bilayer Graphene Nanoribbons On Si(001) By Bias Voltage, Zhuhua Zhang, Changfeng Chen, Xiao Cheng Zeng, Wanlin Guo Jan 2010

Tuning The Magnetic And Electronic Properties Of Bilayer Graphene Nanoribbons On Si(001) By Bias Voltage, Zhuhua Zhang, Changfeng Chen, Xiao Cheng Zeng, Wanlin Guo

Xiao Cheng Zeng Publications

We report on a systematic study of bias-voltage-induced modulation of magnetic and electronic properties of bilayer zigzag graphene nanoribbons (Z-GNRs) on Si(001) substrate by first-principles calculations. We show that the intrinsically nonmagnetic bilayer Z-GNRs exhibit magnetic ordering on the top layer while the bottom layer serves as a nonmagnetic buffer layer when adsorbed on the substrate. Interestingly, the adsorbed bilayers display distinct ribbon-width-dependent magnetoelectric effect under bias voltages. The magnetoelectric coefficient oscillates with increasing ribbon width, which arises from an interesting interplay of the interaction of the bottom ribbon layer with the substrates and the decay length of the localized …

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Observation Of Earlier Two-To-Three Dimensional Structural Transition In Gold Cluster Anions By Isoelectronic Substitution: MauN- (N=8–11; M=Ag,Cu), Lei-Ming Wang, Rhitankar Pal, Wei Huang, Xiao Cheng Zeng, Lai-Sheng Wang Jan 2010

Observation Of Earlier Two-To-Three Dimensional Structural Transition In Gold Cluster Anions By Isoelectronic Substitution: MauN- (N=8–11; M=Ag,Cu), Lei-Ming Wang, Rhitankar Pal, Wei Huang, Xiao Cheng Zeng, Lai-Sheng Wang

Xiao Cheng Zeng Publications

The effects of isoelectronic substitution on the electronic and structural properties of gold clusters are investigated in the critical size range of the two-dimensional (2D)-three-dimensional (3D) structural transition (MAun −, n=8–11; M=Ag,Cu) using photoelectron spectroscopy and density functional calculations. Photoelectron spectra of MAun − are found to be similar to those of the bare gold clusters Aun+1 − , indicating that substitution of a Au atom by a Ag or Cu atom does not significantly alter the geometric and electronic structures of the clusters. The only exception occurs at n …

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Energy Barrier, Charge Carrier Balance, And Performance Improvement In Organic Light-Emitting Diodes, Pavel Anzenbacher Jr., Amare Benor, Shin-Ya Takizawa, C. Pérez-Bolivar Jan 2010

Energy Barrier, Charge Carrier Balance, And Performance Improvement In Organic Light-Emitting Diodes, Pavel Anzenbacher Jr., Amare Benor, Shin-Ya Takizawa, C. Pérez-Bolivar

Chemistry Faculty Publications

The charge injection properties of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate anodes are crucial for performance of organic photovoltaics and organic light-emitting diodes (OLEDs). A simple method for tuning hole injection efficiency using UV-ozone is shown to change anode work-function and optimized carriers balance in the devices and improved efficiency in OLEDs. The optimum time of treatment and work-function differs with device architecture. © 2010 American Institute of Physics.

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Matrix Isolation And Computational Study Of Isodifluorodibromomethane (F2 Cbr-Br): A Route To Br2 Formation In Cf2 Br2 Photolysis, Alexander N. Tarnovsky, Lisa George, Aimable Kalume, Patrick Z. El-Khoury, Scott A. Reid Jan 2010

Matrix Isolation And Computational Study Of Isodifluorodibromomethane (F2 Cbr-Br): A Route To Br2 Formation In Cf2 Br2 Photolysis, Alexander N. Tarnovsky, Lisa George, Aimable Kalume, Patrick Z. El-Khoury, Scott A. Reid

Chemistry Faculty Publications

The photolysis products of dibromodifluoromethane (CF2 Br 2) were characterized by matrix isolation infrared and UV/Visible spectroscopy, supported by ab initio calculations. Photolysis at wavelengths of 240 and 266 nm of CF2 Br2:Ar samples (∼1:5000) held at ∼5 K yielded iso- CF2 Br2 (F2 CBrBr), a weakly bound isomer of CF2 Br2, which is characterized here for the first time. The observed infrared and UV/Visible absorptions of iso- CF2 Br2 are in excellent agreement with computational predictions at the B3LYP/aug-cc-pVTZ level. Single point energy calculations at the CCSD(T)/aug-cc-pVDZ level on the B3LYP optimized geometries suggest that the isoform is a …

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Characterization Of Iso -Cf2 I2 In Frequency And Ultrafast Time Domains, Alexander N. Tarnovsky, Patrick Z. El-Khoury, Lisa George, Aimable Kalume, Scott A. Reid, Bruce S. Ault Jan 2010

Characterization Of Iso -Cf2 I2 In Frequency And Ultrafast Time Domains, Alexander N. Tarnovsky, Patrick Z. El-Khoury, Lisa George, Aimable Kalume, Scott A. Reid, Bruce S. Ault

Chemistry Faculty Publications

The photolysis of diiododifluoromethane (CF2 I2) in condensed phases was studied by a combination of matrix isolation and ultrafast time-resolved spectroscopy, in concert with ab initio calculations. Photolysis at wavelengths of 355 or 266 nm of CF2 I2:Ar samples (1:5000) held at ∼8 K yielded iso -CF2 I2 (F2 C-I-I), a metastable isomer of CF2 I2, characterized here for the first time. The infrared (IR) spectra of this isomer were recorded in matrix experiments, and the derived positions of the C-F stretching modes are in very good agreement with the predictions of high level ab initio calculations, which show that …

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8-Methoxy-4-(4-Methoxyphenyl)Quinoline, Pavel Anzenbacher Jr., Ligia Llovera, Teresa González, Simón E. López Jan 2010

8-Methoxy-4-(4-Methoxyphenyl)Quinoline, Pavel Anzenbacher Jr., Ligia Llovera, Teresa González, Simón E. López

Chemistry Faculty Publications

In the title compound, C 17H 15NO 2, the dihedral angle between the quinoline and benzene ring systems is 62.17 (1)°. In the crystal, zigzag chains propagating in c are linked by C-H⋯O hydrogen bonds, and weak C-H⋯π inter-actions link the chains.

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Revealing Linear Aggregates Of Light Harvesting Antenna Proteins In Photosynthetic Membranes, Yufan He, Xiaohua Zeng, Saptarshi Mukherjee, Suneth Rajapaksha, Samuel Kaplan, H. Peter Lu Jan 2010

Revealing Linear Aggregates Of Light Harvesting Antenna Proteins In Photosynthetic Membranes, Yufan He, Xiaohua Zeng, Saptarshi Mukherjee, Suneth Rajapaksha, Samuel Kaplan, H. Peter Lu

Chemistry Faculty Publications

How light energy is harvested in a natural photosynthetic membrane through energy transfer is closely related to the stoichiometry and arrangement of light harvesting antenna proteins in the membrane. The specific photosynthetic architecture facilitates a rapid and efficient energy transfer among the light harvesting proteins (LH2 and LH1) and to the reaction center. Here we report the identification of linear aggregates of light harvesting proteins, LH2, in the photosynthetic membranes under ambient conditions by using atomic force microscopy (AFM) imaging and spectroscopic analysis. Our results suggest that the light harvesting protein, LH2, can exist as linear aggregates of 4 2 …

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Fabrication And Characterization Of Gel-Type Solar Cells Sensitized By Green-Synthesized Zinc Sulfide Quantum Dots, Adam Alman Jan 2010

Fabrication And Characterization Of Gel-Type Solar Cells Sensitized By Green-Synthesized Zinc Sulfide Quantum Dots, Adam Alman

Undergraduate Honors Theses

Three different types of fully integrated ZnS quantum dot-TiO2 nanoparticle gels were used to create films for usage in photovoltaic cells. The films were annealed onto TEC-8 F:SnO2 conductive glass electrode and the cell was completed by adding a polyolsolvated I/I3 redox couple to the film and capping the cell with a counter electrode constructed of graphite-coated TEC-8 glass. Electrical output of the cells under a 360 W halogen light source and a natural or simulated (1000 W xenon arc lamp) sunlight source were estimated by multi-meter. The highest absolute energy conversion efficiency seen was from an …

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Investigating The Function Of Gd³ + In (Y,Gd)Bo₃:Eu³⁺ Through Transfer Efficiency Measurements, Rosa Lea Rabinovitz Jan 2010

Investigating The Function Of Gd³ + In (Y,Gd)Bo₃:Eu³⁺ Through Transfer Efficiency Measurements, Rosa Lea Rabinovitz

Undergraduate Honors Theses

The optical properties of gadolinium and europium doped samples of yttrium borate were assessed to determine a quantitative value for the host-to-activator energy transfer efficiency under VUV excitation. Emission, excitation, and reflectance data were collected through VUV spectroscopy. A plot of the energy transfer versus europium concentration was used to illustrate the behavior of the system with increasing amounts of europium. a/B ratios for each gadolinium concentration were calculated from trends given by the inverse energy transfer plot. These values show that with an increase of gadolinium in the crystal lattice, the a/B ratio increases. This indicates that there is …

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Characterization Of Phytochemicals Isolated From Plants Of The Pacific Northwest And Western United States For Combating Fungal Multidrug Resistance, John David Schreiber Jan 2010

Characterization Of Phytochemicals Isolated From Plants Of The Pacific Northwest And Western United States For Combating Fungal Multidrug Resistance, John David Schreiber

Undergraduate Honors Theses

Fungal multidrug resistance is an emerging problem for those suffering from fungal infections, and for those seeking to discover or produce novel fungicidal drugs. Plants native to the Pacific Northwest as well as in the Olympic national rainforest were collected and screened for phytochemicals which exhibit direct antifungal activity toward Candida and Saccharomyces spp. as well as those that inhibit fungal ABC transporters that are, in large part, responsible for the development of multidrug resistance. Dalea formosa (Fabaceae), a plant native to the American Southwest, was also screened for phytochemicals of medicinal interest. The methanolic extract of aerial portions of …

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Neuraminidase Activity Of Influenza Virus Strains That Differ In The Ability To Cause Disease, Benjamin Hanks Brown, Bart Tarbet Jan 2010

Neuraminidase Activity Of Influenza Virus Strains That Differ In The Ability To Cause Disease, Benjamin Hanks Brown, Bart Tarbet

Browse All Undergraduate research

Influenza viruses are classified based on their surface glycoproteins: hemagglutinin and neuraminidase.  Hemagglutinin (HA) is responsible for binding to the host cell, while neuraminidase (NA) facilitates escape of newly formed virus particles. These studies determined the NA activity of three subtypes of influenza A virus that differ in their ability to cause disease in mice:  influenza A/NWS/33 (H1N1), influenza A/Victoria/3/75 (H3N2), and influenza A/Duck/MN/1525/81 (H5N1).  Chemiluminescent quantitation of NA activity in equal amounts of each virus was determined in three replicate experiments.  Results indicate that N1 virus subtypes have higher NA activity than do N2 subtypes.  In addition, the NA …

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Discovery And Identification Of New Dna Photoproducts And Investigation Of The Redox Mechanism Of Human Apurinic/Apyrimidinic Endonuclease 1 (Hape1) Protein, Dian Su Jan 2010

Discovery And Identification Of New Dna Photoproducts And Investigation Of The Redox Mechanism Of Human Apurinic/Apyrimidinic Endonuclease 1 (Hape1) Protein, Dian Su

All Theses and Dissertations (ETDs)

Exposure of cells to ultraviolet light results in the formation of DNA photoproducts, many of which have been linked to skin cancer. The majority of these photoproducts arise from a photoreaction between two pyrimidines. Irradiation of double stranded B form DNA under physiological conditions mainly produces adjacent dimers. Nonadjacent photodimers of both intrastrand and interstrand types are much rarer. Intrastrand-type nonadjacent dimers form when one or more nucleotides between two pyrimidines become extrahelical owing to the formation of single strand DNA or a slipped structure. This allows the two pyrimidines to photodimerize in a colinear arrangement, as if the intervening …

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Icosahedral B12-Containing Core–Shell Structures Of B80, Hui Li, Nan Shao, Bo Shang, Lan-Feng Yuan, Jinlong Yang, Xiao Cheng Zeng Jan 2010

Icosahedral B12-Containing Core–Shell Structures Of B80, Hui Li, Nan Shao, Bo Shang, Lan-Feng Yuan, Jinlong Yang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Low-lying icosahedral (Ih) B12-containing structures of B80 are explored, and a number of core–shell isomers are found to have lower energy than the previous predicted B80 fullerene. The structural transformation of boron clusters from tubular structure to core–shell structure may occur at a critical size less than B80.

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Graphene-Like Bilayer Hexagonal Silicon Polymorph, Jaeil Bai, Hideki Tanaka, Xiao Cheng Zeng Jan 2010

Graphene-Like Bilayer Hexagonal Silicon Polymorph, Jaeil Bai, Hideki Tanaka, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We present molecular dynamics simulation evidence for a freezing transition from liquid silicon to quasi-twodimensional (quasi-2D) bilayer silicon in a slit nanopore. This new quasi-2D polymorph of silicon exhibits a bilayer hexagonal structure in which the covalent coordination number of every silicon atom is four. Quantum molecular dynamics simulations show that the stand-alone bilayer silicon (without the confinement) is still stable at 400 K. Electronic band-structure calculations suggest that the bilayer hexagonal silicon is a quasi-2D semimetal, similar to a graphene monolayer, but with an indirect zero band gap.

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Toward A General Approach For Rna-Templated Hierarchical Assembly Of Split-Proteins, Jennifer L. Furman, Ahmed H. Badran, Oluyomi Ajulo, Jason R. Porter, Cliff I. Stains, David J. Segal, Indraneel Ghosh Jan 2010

Toward A General Approach For Rna-Templated Hierarchical Assembly Of Split-Proteins, Jennifer L. Furman, Ahmed H. Badran, Oluyomi Ajulo, Jason R. Porter, Cliff I. Stains, David J. Segal, Indraneel Ghosh

Cliff Stains Publications

The ability to conditionally turn on a signal or induce a function in the presence of a user-defined RNA target has potential applications in medicine and synthetic biology. Although sequence-specific pumilio repeat proteins can target a limited set of ss- RNA sequences, there are no general methods for targeting ssRNA with designed proteins. As a first step toward RNA recognition, we utilized the RNA binding domain of argonaute, implicated in RNA interference, for specifically targeting generic 2-nucleotide, 3′ overhangs of any dsRNA. We tested the reassembly of a split-luciferase enzyme guided by argonaute-mediated recognition of newly generated nucleotide overhangs when …

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Evaluation Of Solid-Phase Extraction Sorbent With Ketoimine Groups For The Preconcentration Of Benzene And Phenolic Compounds In Water, Iwona Rykowska, Wieslaw Wasiak Jan 2010

Evaluation Of Solid-Phase Extraction Sorbent With Ketoimine Groups For The Preconcentration Of Benzene And Phenolic Compounds In Water, Iwona Rykowska, Wieslaw Wasiak

Turkish Journal of Chemistry

The applicability of silica gel, modified with ketoimine groups, to solid phase extraction (SPE) was tested. Basic characteristics of the modified silica were determined using elemental analysis, and ^{29}Si CP MAS NMR spectroscopy, as well as measurement of specific surface area. Some applications of the sorbent studied to preconcentration and further determination of organic compounds, such as benzene, phenol, and o-chlorophenol, by means of solid-phase extraction (SPE) and gas chromatography are presented. The determined recovery rates were about 95%-98%.

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Inhibition Of Nonsense-Mediated Mrna Decay By Antisense Morpholino Oligonucleotides Restores Functional Expression Of Herg Nonsense And Frameshift Mutations In Long-Qt Syndrome, Qiuming Gong, Matthew R. Stump, Zhengfeng Zhou Jan 2010

Inhibition Of Nonsense-Mediated Mrna Decay By Antisense Morpholino Oligonucleotides Restores Functional Expression Of Herg Nonsense And Frameshift Mutations In Long-Qt Syndrome, Qiuming Gong, Matthew R. Stump, Zhengfeng Zhou

Faculty Publications - Department of Biological & Molecular Science

Mutations in the human ether-a-go-go-related gene (hERG) cause long-QT syndrome type 2 (LQT2). We previously described a homozygous LQT2 nonsense mutation Q1070X in which the mutant mRNA is degraded by nonsense-mediated mRNA decay (NMD) leading to a severe clinical phenotype. The degradation of the Q1070X transcript precludes the expression of truncated but functional mutant channels. In the present study, we tested the hypothesis that inhibition of NMD can restore functional expression of LQT2 mutations that are targeted by NMD. We showed that inhibition of NMD by RNA interference-mediated knockdown of UPF1 increased Q1070X mutant channel protein expression and hERG current …

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Mutational Studies Uncover Non-Native Structure In The Dimeric Kinetic Intermediate Of The H2a–H2b Heterodimer, Matthew R. Stump, Lisa M. Gloss Jan 2010

Mutational Studies Uncover Non-Native Structure In The Dimeric Kinetic Intermediate Of The H2a–H2b Heterodimer, Matthew R. Stump, Lisa M. Gloss

Faculty Publications - Department of Biological & Molecular Science

The folding pathway of the histone H2A–H2B heterodimer minimally includes an on-pathway, dimeric, burst-phase intermediate, I2. The partially folded H2A and H2B monomers populated at equilibrium were characterized as potential monomeric kinetic intermediates. Folding kinetics were compared for initiation from isolated, folded monomers and the heterodimer unfolded in 4 M urea. The observed rates were virtually identical above 0.4Murea, exhibiting a log-linear relationship on the final denaturant concentration. Below ∼0.4 M urea (concentrations inaccessible from the 4-M urea unfolded state), a rollover in the rates was observed; this suggests that a component of the I2 ensemble contains non-native structure that …

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Assimilative Domain Proficiency And Performance In Chemistry Coursework, Scott William Byrnes Jan 2010

Assimilative Domain Proficiency And Performance In Chemistry Coursework, Scott William Byrnes

Walden Dissertations and Doctoral Studies

The assimilation and synthesis of knowledge is essential for students to be successful in chemistry, yet not all students synthesize knowledge as intended. The study used the Learning Preference Checklist to classify students into one of three learning modalities -- visual, auditory, or kinesthetic (VAK). It also used the Kolb Learning Style Inventory (KLSI), which utilizes four learning domains - Converging, Accommodating, Diverging, and Assimilating - to explain the students' maturation process by showing shift from any domain towards the Assimilating domain. A shift approaching this domain was considered as improvement in the assimilation and synthesis of knowledge. This pre-experimental …

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Ionic Liquids In Analytical Chemistry And Calix[4]Arene Chemistry Of Nox Gases, Eranda Pathirana Wanigasekara Jan 2010

Ionic Liquids In Analytical Chemistry And Calix[4]Arene Chemistry Of Nox Gases, Eranda Pathirana Wanigasekara

Chemistry & Biochemistry Dissertations - Archive

Application of ionic liquids (ILs) in analytical chemistry can be numerous. The use of ILs in analytical techniques including gas chromatography (GC), electrospray ionization mass spectrometry (ESI-MS), capillary electrophoresis (CE), high performance liquid chromatography (HPLC), solid phase microextraction (SPME) and spectroscopy have attracted great attention of scientific community in the past few decades. Many advancements in this field are due to the development of multiply charged, multifunctional ionic liquids.This dissertation mainly consists of two parts. The first part focuses on the use of new, structurally diverse, chemically robust ionic liquids for GC, SPME and ESI-MS applications. Within this section, highly …

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Nanopore Stochastic Sensing With Ionic Liquid Supporting Electrolyte And Ionic Liquid Based Water Quantitation Using Gas Chromatography, Dilani A. Jayawardhana Jan 2010

Nanopore Stochastic Sensing With Ionic Liquid Supporting Electrolyte And Ionic Liquid Based Water Quantitation Using Gas Chromatography, Dilani A. Jayawardhana

Chemistry & Biochemistry Dissertations - Archive

This dissertation focuses toward finding two new avenues to explore the properties of ionic liquids (ILs). First, ILs has been used as a novel, and advantageous supporting electrolytes in nanopore stochastic sensing technology. Here, the sensing element is the alpha hemolysin protein, while a solution containing an ionic liquid will be used as the background electrolyte, instead of the typical used NaCl/KCl solution. This method employs single-channel recording with the planar lipid bilayer technique, where current modulation represents individual binding events. In this study, a useful means of implementing IL salt solutions will be demonstrated. Specifically, its great enhancements of …

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The Use Of Ionic Liquid Based Salts In Gas Chromatography And Electrospray Ionization Mass Spectrometry, Zachary Steven Breitbach Jan 2010

The Use Of Ionic Liquid Based Salts In Gas Chromatography And Electrospray Ionization Mass Spectrometry, Zachary Steven Breitbach

Chemistry & Biochemistry Dissertations - Archive

This dissertation focuses on two uses for Room Temperature Ionic Liquids (RTILs). First, RTILs will be used to produce novel Gas Chromatographic (GC) stationary phases. The use of new phosphonium based RTIL GC columns for one-dimensional and two-dimensional GC will be discussed. The high thermal stability and unique orthogonality of these phases will be demonstrated. Additionally, the development of the first tricationic RTIL based GC stationary phases will be presented. The exceptional peak shape for polar compounds and thermal stability of these stationary phases are examined. Furthermore, the solvation properties of these novel solvents will be described via a linear …

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Estrogen Analysis By Liquid Chromatography - Mass Spectrometry, Hien P. Nguyen Jan 2010

Estrogen Analysis By Liquid Chromatography - Mass Spectrometry, Hien P. Nguyen

Chemistry & Biochemistry Dissertations - Archive

Estrogens are well known as female hormones associated with both health and disease. Although they have been reported as potential carcinogens, their use as therapy in the treatment of neurodegeneration has recently received a great deal of attention. The main goal of this work was to advance estrogen analysis using liquid chromatography - mass spectrometry (LC-MS) and associated techniques in order to support pre-clinical and clinical research on the neuroprotective effects of estrogens. Native estrogen analyses were performed in different types of biological samples, including human cerebrospinal fluid (CSF), horse serum, phosphate buffered saline - bovine serum albumin (PBS-BSA), mouse …

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Total Synthesis Of Cyclooroidin And Studies Towards Some Oroidin Dimers, Sabuj Mukherjee Jan 2010

Total Synthesis Of Cyclooroidin And Studies Towards Some Oroidin Dimers, Sabuj Mukherjee

Chemistry & Biochemistry Dissertations - Archive

This dissertation consists of two parts. The first part describes the synthesis of northern fragment of nagelamide R and the enantioselective total synthesis of cyclooroidin. The oroidin family of marine natural products is a growing group of marine sponge-derived alkaloids which contain 2-aminoimidazole and pyrrolecarboxamide fragments as their signature features. The structural complexity, and in many cases interesting biological profiles, of these compounds has rendered several of these natural products as targets of interest. In the context of nagelamide R, the key transformation involves the intramolecular cyclization of a pyrrolecarboxamide via the carbonyl oxygen leading to the formation of oxazoline, …

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Elucidation Of The Structure And Recognition Properties Of Antimony(Iii)-Tartrate Using Electrospray Ionization Mass Spectrometry, Aruna B. Wijeratne Jan 2010

Elucidation Of The Structure And Recognition Properties Of Antimony(Iii)-Tartrate Using Electrospray Ionization Mass Spectrometry, Aruna B. Wijeratne

Chemistry & Biochemistry Dissertations - Archive

Chirality of molecules is a major topic in the design, discovery and development of new drugs. Currently, analytical chemistry research divisions are challenged to find new methods to screen enantiospecific molecular recognition properties of potential chiral drug candidates with targeted biological molecules in a time-sensitive environment. Recently, mass spectrometry (MS) has received significant attention for its use in studying molecular recognition systems. Electrospray ionization mass spectrometry (ESI-MS) has received the most attention for the investigation of stereochemical association phenomena, due to its capacity to transfer solution phase chiral interactions into the gas phase for analysis in single-stage mass spectra. ESI-MS …

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Application Of Pd-Catalyzed Reactions In The Total Synthesis Of Oroidin-Derived Alkaloids, Manojkumar R. Bhandari Jan 2010

Application Of Pd-Catalyzed Reactions In The Total Synthesis Of Oroidin-Derived Alkaloids, Manojkumar R. Bhandari

Chemistry & Biochemistry Dissertations - Archive

The oroidin family of marine natural products is a growing group of sponge-derived alkaloids which contain 2-aminoimidazole and pyrrolecarboxamide fragments as their signature features. Due to their structural diversity and biological activity, many groups are interested in the total synthesis of these natural products. It has been proposed that many of the alkaloids in this family are produced in nature simply by dimerization and/or cyclization of the simplest member, oroidin. In this dissertation we have attempted to explore these biosynthetic relationships to complete the total synthesis of several oridin-derived natural products. This dissertation consists of two parts. The first part …

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Analytical Characterization Of Anthocyanins From Natural Products By Reverse-Phase Liquid Chromatography-Photodiode Array-Electrospray Ionization-Ion Trap-Time Of Flight Mass Spectrometry, Jeremy S. Barnes Jan 2010

Analytical Characterization Of Anthocyanins From Natural Products By Reverse-Phase Liquid Chromatography-Photodiode Array-Electrospray Ionization-Ion Trap-Time Of Flight Mass Spectrometry, Jeremy S. Barnes

Chemistry & Biochemistry Theses - Archive

Anthocyanins are known to be one of the most powerful phytochemical antioxidant and believed to have a positive influence on a variety of health conditions. Numerous studies continue on these compounds that are readily found in most plants. Red hybrid-tea rose petals and wild blueberries were used as model systems for optimizing the extraction and identification process of anthocyanins in plant material using high performance liquid chromatography (HPLC) and mass spectrometry (MS) without the use of authentic standards. A number of extraction parameters, including sample homogenization, solvent selection and acid type and amount, were varied to examine the effects on …

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Physical And Biochemical Assessment Of Mexican Palo Verde Response To Chromium Toxicity, Yong Zhao Jan 2010

Physical And Biochemical Assessment Of Mexican Palo Verde Response To Chromium Toxicity, Yong Zhao

Open Access Theses & Dissertations

In the United States, about 1/3 of the 1400 superfund sites have been reported to be chromium contaminated, making chromium the second most common metal found in superfund chemical contamination sites. Chromium removal from soil has commonly been carried out via chemical, physical, and thermal processes. However, these methods are expensive and/or invasive to local ecosystems. In contrast to these techniques, phytoremediation (the use of plants to remove toxic substances from areas containing contamination at low or medium levels) appears to be a cost-effective and environmentally friendly process for chromium removal. However, most reports on chromium phytoremediation suggest that this …

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