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Articles 181 - 210 of 291
Full-Text Articles in Biochemistry
Novel Perturbation Approach For The Structure Factor Of The Attractive Hard-Core Yukawa Fluid, Andrij Trokhymchuk, Roman Melnyk, Filip Moucka, Ivo Nezbeda
Novel Perturbation Approach For The Structure Factor Of The Attractive Hard-Core Yukawa Fluid, Andrij Trokhymchuk, Roman Melnyk, Filip Moucka, Ivo Nezbeda
Faculty Publications
A novel perturbation approach for the structure factor S(k) of the Lennard-Jones-type Yukawa fluid with z=1.8 is presented. An approach is based on a new reference system, that is, the short-range Yukawa model with z0 > z=1.8. By choosing for the reference system the value z0=6, it is shown that (i) the proposed approach for S(k) performs much better than the traditional hard-sphere reference perturbation method does; (ii) the use of an approximate mean spherical (MSA) description of the reference structure factor provides the results for S(k) that are more accurate as those obtained from the direct MSA computations; and (iii) …
Compartmentalization Of Hiv-1 In The Secondary Lymphoid Tissues, James Peter Gregson
Compartmentalization Of Hiv-1 In The Secondary Lymphoid Tissues, James Peter Gregson
Theses and Dissertations
Follicular dendritic cells (FDCs) reside in the lymphoid follicles of the secondary lymphoid tissues (sLTs). Following the infection of an individual with human immunodeficiency virus type 1 (HIV-1), viral particles are trapped in massive quantities on the surfaces of FDCs. HIV-1 viral compartments are cell types or tissues between which there is a restriction of virus flow. Compartmentalization of HIV-1 creates numerous sites within the body in which the virus can undergo independent evolution, giving rise to a more diverse total viral population. Given the sessile nature of the FDC, I hypothesized that contrary to common assumptions, FDC-trapped HIV-1 is …
Development Of Chemomechanical Functionalization And Nanografting On Silicon Surfaces, Michael Vernon Lee
Development Of Chemomechanical Functionalization And Nanografting On Silicon Surfaces, Michael Vernon Lee
Theses and Dissertations
Progress in chemomechanical functionalization was made by investigating the binding of molecules and surface coverage on the silicon surface, demonstrating functionalization of silicon with gases by chemomechanical means, analyzing atomic force microscopy probe tip wear in atomic force microscopy (AFM) chemomechanical nanografting, combining chemomechanical functionalization and nanografting to pattern silicon with an atomic force microscope, and extending chemomechanical nanografting to silicon dioxide. Molecular mechanics of alkenes and alkynes bound to Si(001)-2x1 as a model of chemomechanically functionalized surfaces indicated that complete coverage is energetically favorable and becomes more favorable for longer chain species. Scribing a silicon surface in the presence …
Synthesis Of Resveratrol And Its Analogs, Phase-Transfer Catalyzed Asymmetric Glycolate Aldol Reaction, And Total Synthesis Of 8,9-Methylamido-Geldanamycin, Jing Liu
Theses and Dissertations
The phytoalexin resveratrol and its acetyl analogs have been made using a decarbonylative Heck reaction. The acid chloride derived from 3,5-dihydroxybenzoic acid was coupled with suitable protected 4-hydroxystyrene in the presence of palladium acetate and N,N-bis-(2,6-diisopropylphenyl)-4,5-dihydro imidazolium chloride to give the substituted stilbene in good yield as the key step. Human HL-60 cell assays showed the 4'-acetyl resveratrol variant improved activity (ED50 17 μM) relative to resveratrol (24 μM). Cinchona phase-transfer catalysts (PTC) were developed for glycolate aldol reactions to give differentially protected 1,2-diol products. Silyl enol ether of diphenylmethoxy-2,5-dimethoxyacetophenone reacted to generate benzhydryl-protected products. O-Allyl trifluorobenzyl cinchonium hydrodifluoride (20 …
Synthesis And Antiviral Evaluation Of Some 3'-Carboxymethyl-3'-Deoxyadenosine Derivatives, Houguang Shi
Synthesis And Antiviral Evaluation Of Some 3'-Carboxymethyl-3'-Deoxyadenosine Derivatives, Houguang Shi
Theses and Dissertations
3'-Carboxymethyl-3'-deoxyadenosine derivatives were prepared from 2'-O-TBDMS-3'-deoxy-3'-[(ethoxycarbonyl)methyl]adenosine (1) via simple and efficient procedures. Conversion of 1 to 5'-azido-2'-O-TBDMS-3', 5'-dideoxy -3'-[(ethoxycarbonyl) methyl] adenosine (4) was accomplished via a novel one-pot method employing 5'-activation (TosCl) followed by efficient nucleophilic displacement with tetramethylguanidinium azide. Compound 4 was converted to a 5'-[(N-methylcarbamoyl)amino] derivative (5) via one-pot reduction/acylation employing H2/Pd-C followed by treatment with p-nitrophenyl N-methylcarbamate. The latter step of this two-step process required an efficient source of p-nitrophenyl N-methylcarbamate, thus a highly efficient new method for preparing p-nitrophenyl N-alkylcarbamate was developed. N6-phenylcarbamoyl groups were introduced by treatment with phenylisocyanate, and an efficient new method for …
Asymmetric Dihydroxylation And Aziridination Of Allenes And Related Chemistry, Renmao Liu
Asymmetric Dihydroxylation And Aziridination Of Allenes And Related Chemistry, Renmao Liu
Theses and Dissertations
A novel method for asymmetric synthesis of α-hydroxy ketone with excellent regio- and stereoselectivity has been established by the systematic investigation of asymmetric dihydroxylation of allenes. The efficiency of kinetic resolution of racemic allenes was also investigated by using the AD reaction on both 1,3-disubstituted and trisubstituted allenes. Steric effects, electronic effects and allene substitution are also discussed. Aziridines were formed by copper-catalyzed intramolecular nitrene addition to alkenes. The carbamate group was used as the tether between the alkene and the nitrene. Subsequent nucleophilic attack of the aziridine was accomplished using RSH, R2NH, N3-,or ROH as the nucleophile. This addition …
Towards Early State Disease Detection In Microdevices: Fabrication And Testing Of Micro Total Analysis Systems For Bioanalytical Applications, Tao Pan
Theses and Dissertations
The past few years have seen a rapid expansion in interest in the characterization of the entire complement of proteins, or proteome. Micro total analysis systems (μTAS) are an emerging promising method, offering rapid, sensitive and low sample consumption separations. I have demonstrated microchip capillary electrophoresis (CE) devices made of CaF2. New methods have been developed for micromachining enclosed capillaries in CaF2. CE analysis of fluorescently labeled amino acids was used to illustrate bioanalytical applications of these microdevices. Initial on-chip infrared spectroscopy results for qualitative analyte identification were achieved in microfluidic CaF2 channels. I have also shown the evaluation of …
Kinetic Studies Of 6-Halopurine Nucleoside In Snar Reactions; 6-(Azolyl, Alkylthio And Fluoro)-Purine Nucleosides As Substrates For Suzuki Reactions, Jiangqiong Liu
Theses and Dissertations
In chapter 1, we describe development of a mild and efficient method for SNAr iodination of 6-chloropurine 2'-deoxynucleosides and nucleosides. Our studies demonstrate that 6-iodopurine nucleosides are excellent substrates for certain transition metal-catalyzed cross-coupling reactions. In chapter 2, we describe synthesis of protected 6-fluoro, 6-chloro, 6-bromo and 6-sulfonylpurine nucleosides. Comparisons among 6-fluoro-, 6-chloro-, 6-bromo, 6-iodo and 6-sulfonylpurine nucleosides for SNAr reactions with various N, O and S nucleophiles were investigated. Our results demonstrate that the 6-fluoropurine nucleoside is the best substrate for SNAr reactions among the four 6-halopurine nucleosides with oxygen, sulfur and aliphatic amine nucleophiles, and also with an …
Dna-Templated Nanomaterials, Hector Alejandro Becerril-Garcia
Dna-Templated Nanomaterials, Hector Alejandro Becerril-Garcia
Theses and Dissertations
Nanomaterials display interesting physical and chemical properties depending on their shape, size and composition. Self assembly is an intriguing route to producing nanomaterials with controllable compositions and morphologies. DNA has been used to guide the self assembly of materials, resulting in: (1) metal nanowires; (2) metal or semiconductor nanorods; (3) carbon nanotubes; and (4) semiconductor, metal or biological nanoparticles. My work expands the range of DNA templated nanomaterials and develops novel ways of using DNA to pattern nanostructures on surfaces. I have performed the first synthesis of silver nanorods on single stranded DNA, an attractive material for localizing DNA coupled …
Investigation Of Novel Microseparation Techniques, Yansheng Liu
Investigation Of Novel Microseparation Techniques, Yansheng Liu
Theses and Dissertations
Ultrahigh pressure liquid chromatography (UHPLC) makes it possible to use very small particles (< 2 µm) as packing materials to provide high column efficiencies. Results from a careful comparison of small porous and nonporous particles show that when the particle size is small enough (< 2 µm), both porous and nonporous particles give excellent performance, and the differences in column efficiencies between porous and nonporous particles become insignificant. Columns packed with bare diamond particles could separate small molecules, especially polar molecules, however, severe tailing occurred for less polar compounds. The polybutadiene coated diamond particles gave greater retention and better separation of small molecules compared to bare particles, although no improvement in column efficiency was observed. Changes in surface bonding of thermally hydrogenated diamond particles was achieved by chemical modification using various organic peroxides with or without reagents containing long carbon chain functional groups. It appears that the alkyl groups were attached onto the diamond surface with limited coverage. LC experiments did not demonstrate good separation; however, changes in LC behavior were observed. A repetitive solvent programming approach was successfully applied to the analysis of a continuous sample stream in microbore LC. Each analysis cycle consisted of three steps: pseudo-injection, elution and rinse. In the pseudo-injection step, elution with a non- or poor-eluting solvent produced a concentrated sample plug due to on-column focusing. Factors influencing peak symmetry, resolution and analysis cycle length were investigated. Quantitative analysis of a continuous sample stream is possible under certain operating conditions. Electric field gradient focusing (EFGF) devices with distributed resistor substrates could focus proteins in the separation channel, however, the focused bands were not stable, and the repeatability was poor due to the formation of bubbles and pH gradient in the separation channel. Both fiber-based and porous glass capillary-based planar EFGF devices with changing cross-sectional area (CCSA) channels were constructed and evaluated with the aid of a home-made scanning laser-induced fluorescence detection system. The fiber-based CCSA EFGF devices gave poorer performance compared with glass capillary based devices. Porous glass capillary-based EFGF devices could focus single proteins and separate mixtures of two to three proteins.
The Role Of Phosducin-Like Protein As A Co-Chaperone With The Cytosolic Chaperonin Complex In Assembly Of The G Protein Βγ Subunit Dimer, Paul Jayson Ludtke
The Role Of Phosducin-Like Protein As A Co-Chaperone With The Cytosolic Chaperonin Complex In Assembly Of The G Protein Βγ Subunit Dimer, Paul Jayson Ludtke
Theses and Dissertations
Phosducin-like protein (PhLP) has been shown to interact with the cytosolic chaperonin containing TCP-1 (CCT), and the βγ subunit dimer of heterotrimeric G proteins (Gβγ). Here we provide details obtained from cryo-electron microscopic and biochemical studies on the structure of the complex between the cytosolic chaperonin CCT and PhLP. Binding of PhLP to CCT occurs through only one of the two chaperonin rings, making multiple contacts with CCT through both its N- and C-terminal domains. In addition, we show that PhLP acts as a co-chaperonin along with CCT in mediating the assembly of the G protein βγ subunit and that …
The Niemann-Pick Type C2 Protein Loads Isoglobotrihexosylceramide Onto Cd1d Molecules And Contributes To The Thymic Selection Of Nkt Cells, Paul B. Savage, Nicolas Schrantz, Yuval Sagiv, Yang Liu, Albert Bendelac, Luc Teyton
The Niemann-Pick Type C2 Protein Loads Isoglobotrihexosylceramide Onto Cd1d Molecules And Contributes To The Thymic Selection Of Nkt Cells, Paul B. Savage, Nicolas Schrantz, Yuval Sagiv, Yang Liu, Albert Bendelac, Luc Teyton
Faculty Publications
The Niemann-Pick type C2 (NPC2) protein is a small, soluble, lysosomal protein important for cholesterol and sphingolipid transport in the lysosome. The immunological phenotype of NPC2-deficient mice was limited to an impaired thymic selection of Valpha 14 natural killer T cells (NKT cells) and a subsequent reduction of NKT cells in the periphery. The remaining NKT cells failed to produce measurable quantities of interferon-gamma in vivo and in vitro after activation with alpha-galactosylceramide. In addition, thymocytes and splenocytes from NPC2-deficient mice were poor presenters of endogenous and exogenous lipids to CD1d-restricted Valpha 14 hybridoma cells. Importantly, we determined that similar …
Synthesis And Optical Properties Of Four Oligothiophene-Ruthenium Complexes And Synthesis Of A Bidentate Ligand For C-F Bond Activation, Joseph S. Bair
Synthesis And Optical Properties Of Four Oligothiophene-Ruthenium Complexes And Synthesis Of A Bidentate Ligand For C-F Bond Activation, Joseph S. Bair
Theses and Dissertations
Photovoltaic cells and fluorescence sensing are two important areas of research in chemistry. The combination of photon-activated electron donors with electron acceptors provides a strong platform for the study of optical devices. A series of four oligothiophene-ruthenium complexes has been synthesized. Variation in oligothiophene length and bipyridine substitution allowed comparison of these variables on electronic properties. The longer oligothiophenes display lower energy absorption and emission compared to the shorter ones. Aromatic conjugation appears more complete with para-, rather than meta-, substitution. Oligothiophenes and Ru(bpy)32+ are highly fluorescent individually, but fluorescence is quenched when connected. Bonds of carbon to fluorine are …
Development Of Polymer Monoliths For The Analysis Of Peptides And Proteins, Binghe Gu
Development Of Polymer Monoliths For The Analysis Of Peptides And Proteins, Binghe Gu
Theses and Dissertations
Several novel polymer monoliths for the analysis of peptides and proteins were synthesized using polyethylene glycol diacrylate (PEGDA) as crosslinker. Photo-initiated copolymerization of polyethylene glycol methyl ether acrylate and PEGDA yielded an inert monolith that could be used for size exclusion liquid chromatography of peptides and proteins. This macroscopically uniform monolith did not shrink or swell in either water or tetrahydrofuran. More importantly, it was found to resist adsorption of both acidic and basic proteins in aqueous buffer without any organic solvent additives. A strong cation-exchange polymer monolith was synthesized by copolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and PEGDA. A ternary …
Development Of Methods For The Study Of Phosphoproteins, Zhaoyuan Chen
Development Of Methods For The Study Of Phosphoproteins, Zhaoyuan Chen
Theses and Dissertations
Characterization of phosphoproteins-including detection, identification of phosphoproteins and identification of phosphorylation sites-is mostly done with radiolabeling and proteomic techniques. Three main topics related to phosphoprotein characterization are included in this dissertation. First, large-scale characterization of the CHO (Chinese hamster ovary) cell phosphoproteome was done using two dimensional gel electrophoresis (2DE) separation, visualization of phosphoproteins by radiolabeling or a phosphoprotein specific dye, followed by MALDI-TOF identification. Because radiolabeling of phosphoproteins is very sensitive and straightforward to quantify, such analysis can give a clear picture of the relative phosphosphorylation of proteins present in a sample. But there are also limitations to this …
Capillary Electrophoresis Of Proteins With Selective On-Line Affinity Monoliths, Jenny Marcela Armenta Blanco
Capillary Electrophoresis Of Proteins With Selective On-Line Affinity Monoliths, Jenny Marcela Armenta Blanco
Theses and Dissertations
The analysis of proteins in biological fluids by capillary electrophoresis (CE) is of interest in clinical chemistry. However, due to low analyte concentrations and poor concentration limits of detection (CLOD), protein analysis by this technique is frequently challenging. Coupling preconcentration techniques with CE greatly improves the CLOD. An on-line preconcentration-CE method that can selectively preconcentrate any protein for which an antibody is available would be very useful for the analysis of low abundance proteins and would establish CE as a major tool in biomarker discovery. To accomplish this, an on-line protein G monolithic preconcentrator CE system for enrichment and separation …
Biochemical Investigations Of Macular Degeneration: The Significance Of Protein Oxidation Including Novel Methods For Its Study, Sarah Warburton
Biochemical Investigations Of Macular Degeneration: The Significance Of Protein Oxidation Including Novel Methods For Its Study, Sarah Warburton
Theses and Dissertations
The retinal pigment epithelium (RPE) is a monolayer of cells located directly behind the photoreceptor cells in the retina. These cells are involved in a variety of functions that support the visual process in the eye, namely 1) they form a blood-retina barrier which separates the neural retina from the choroid's blood supply, 2) the apical processes of RPE cells diurnally phagocytose the outer segments of photoreceptor cells, and 3) they participate in the renewal of the photopigment 11-cis retinal. Age-related macular degneration (AMD) is the leading cause of blindness in people over the age of 50 years in North …
Characterization Of Cucurbituril Complex Ions In The Gas Phase Using Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Haizhen Zhang
Theses and Dissertations
Host-guest interactions have been well studied in the new century to obtain fundamental insights into supramolecular chemistry. Most of the pioneering works have been done using techniques such as NMR, X-ray crystallography, IR spectroscopy and so on. However, none of these techniques is universal for the investigation of all types of supramolecules, and usually they have one or more limiting factors such as relatively large sample consumption, matrix effects from solvents, etc. Electrospray mass spectrometry has been widely used to investigate host-guest interactions in the gas phase. A particular advantage of gas phase host-guest research is that the experimental results …
Periodic Boundary Condition Induced Breakdown Of The Equipartition Principle And Other Kinetic Effects Of Finite Sample Size In Classical Hard-Sphere Molecular Dynamics Simulation, Randall B. Shirts, Scott R. Burt, Aaron M. Johnson
Periodic Boundary Condition Induced Breakdown Of The Equipartition Principle And Other Kinetic Effects Of Finite Sample Size In Classical Hard-Sphere Molecular Dynamics Simulation, Randall B. Shirts, Scott R. Burt, Aaron M. Johnson
Faculty Publications
We examine consequences of the non-Boltzmann nature of probability distributions for one-particle kinetic energy, momentum, and velocity for finite systems of classical hard spheres with constant total energy and nonidentical masses. By comparing two cases, reflecting walls (NVE or microcanonical ensemble) and periodic boundaries (NVEPG or molecular dynamics ensemble), we describe three consequences of the center-of-mass constraint in periodic boundary conditions: the equipartition theorem no longer holds for unequal masses, the ratio of the average relative velocity to the average velocity is increased by a factor of [N/(N–1)]^1/2, and the ratio of average collision energy to average kinetic energy is …
Microfabrication And Evaluation Of Planar Thin-Film Microfluidic Devices, Bridget Ann Peeni
Microfabrication And Evaluation Of Planar Thin-Film Microfluidic Devices, Bridget Ann Peeni
Theses and Dissertations
Over the past 15 years, research in the field of microfluidics has rapidly gained popularity. By seeking to miniaturize and automate separation-based analysis, microfluidic research seeks to improve current methods through decreased cost, analysis time, and sources of contamination. My work has focused on developing a novel fabrication method, based on standard microfabrication techniques, to create thin-film microfluidic devices. This microfabrication format makes it possible to generate devices that provide high efficiencies, enable mass fabrication, and provide a platform capable of integrating the microfluidic and electronic components necessary for a micro-total analysis system (μ-TAS). Device fabrication combines the processes of …
Detection Of Proteins By Two-Photon Excitation Of Native Fluorescence, Li Li
Detection Of Proteins By Two-Photon Excitation Of Native Fluorescence, Li Li
Theses and Dissertations
Proteins are of primary importance to the structure and function of all living cells. Study of proteins relies on the ability to separate a complex mixture so that individual proteins can be more easily processed by other techniques. Since protein samples often exist at low concentration in a small volume, the trend in chemical analysis is toward micro total analysis systems (µTAS) or lab-on-a-chip devices. Among µTAS separation methods, the relatively new electric field gradient focusing (EFGF) technique has shown potential. It focuses and separates analytes based on their electrophoretic migration in an opposing hydrodynamic flow. The detection principles that …
Ferritin: Mechanistic Studies And Electron Transfer Properties, Bo Zhang
Ferritin: Mechanistic Studies And Electron Transfer Properties, Bo Zhang
Theses and Dissertations
Ferritins are ubiquitous iron storage proteins in living systems. Although much is known about the iron deposition process in ferritin and a mechanism has been developed, several important issues still remain unknown. One lingering question is the less than stoichiometric quantities of hydrogen peroxide detected in previous studies on animal ferritins. Extensive experimental data on identifying the species in competition for peroxide equivalents point to a surprising conclusion that H2O2 generated in the ferroxidase reaction is consumed by amine buffers that are commonly employed in in vitro ferritin studies, while non-nitrogen containing buffers, such as acetate, phosphate, and carbonate, do …
Structure-Activity Studies Of Glycosphingolipids As Antigens Of Natural Killer T Cells, Randal Donald Goff
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 …
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
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 …
Dna-Templated Surface Alignment And Characterization Of Carbon Nanotubes., Huijun Xin
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. …
Enhanced Electrospray Ionization For Mass Spectrometry And Ion Mobility Spectrometry, Li Zhou
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 …
Electric Field Gradient Focusing-Uv Detection For Protein Analysis, Shu-Ling Lin
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 …
Model Studies Towards The Total Synthesis Of Lyconadin A Via An Acyl Radical Cascade Reaction, Koudi Zhu
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 …
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
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 …
Fabrication Of Polymeric Microfluidic Devices For Protein Analysis, Jikun Liu
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 …