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Articles 1 - 8 of 8

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Capillary Liquid Chromatography Using Micro Size Particles, Yanqiao Xiang Jul 2004

Capillary Liquid Chromatography Using Micro Size Particles, Yanqiao Xiang

Theses and Dissertations

High speed and/or high efficiency separations can be realized using small particles (~ 1 ┬Ám) in liquid chromatography (LC). However, due to the large pressure drop caused by small particles, conventional LC pumping systems cannot satisfy the pressure requirements needed to drive the mobile phase through the column. Use of ultrahigh pressure, elevated temperature, or both can overcome these pressure limitations and allow the use of very small particles for high speed and/or high efficiency separations.

In this dissertation, the use of ultrahigh pressures with and without elevated temperatures in capillary LC is described. Very fast separations of various ...


Velocity And Temperature Characterization Of The First Vacuum Stage Expansion In An Inductively Coupled Plasma - Mass Spectrometer, William Neil Radicic May 2004

Velocity And Temperature Characterization Of The First Vacuum Stage Expansion In An Inductively Coupled Plasma - Mass Spectrometer, William Neil Radicic

Theses and Dissertations

The inductively coupled plasma - mass spectrometer (ICP-MS) is the analytical instrument of choice for trace element detection and quantification. Despite the popularity of ICP-MS, significant degradation in sensitivity and precision occurs as the result of matrix and instrument-induced effects. The sources of these effects are not well understood, characterized, or correlated to particular plasma operating condition settings or matrix compositions and involve both neutral and charged species. The purpose of this study is to characterize the behavior of metastable Ar (I) atom and Ca (II) ion through the measurement of Doppler velocities and fluorescence line width "temperatures."

For the characterization ...


N9 Alkylation And Glycosylation Of Purines; A Practical Synthesis Of 2-Chloro-2'-Deoxyadenosine, Minghong Zhong May 2004

N9 Alkylation And Glycosylation Of Purines; A Practical Synthesis Of 2-Chloro-2'-Deoxyadenosine, Minghong Zhong

Theses and Dissertations

(a) The Robins reagent [2-acetamido-6-O-(diphenylcarbamoyl)purine] was utilized for glycosylation under Lewis acid conditions. Regioselectivity of glycosylation depends on the glycosyl donor and its 2-O- or 2-N-protecting group. Regioselective N9 glycosylation of 2-acetamido-6-O-(diphenylcarbamoyl)purine with problematic glucosamine has been accomplished by protecting the amino function as a phthalimido group with consequent stabilization of the oxocarbenium cation, and lowering the activation energy by introduction of trichloroacetimidate at the anomeric carbon.

(b) 6-Heteroaryl functions [6-(1,2,4-triazol-4-yl) and 6-(imidazol-1-yl)] were introduced into purine derivatives for regioselective N9 alkylation. The regiospecificity of alkylation mainly results from steric effects due ...


Fluorescence Detectors For Proteins And Toxic Heavy Metals, Uchenna Prince Paul Apr 2004

Fluorescence Detectors For Proteins And Toxic Heavy Metals, Uchenna Prince Paul

Theses and Dissertations

An inexpensive detector for proteins is described. The detection technique was based on two-photon excitation intrinsic protein fluorescence using a visible 532 nm diode-pumped nano laser as the excitation source. Proteins that exhibit intrinsic fluorescence must contain at least one tryptophan, tyrosine, or phenylalanine residue in their amino acid sequences. The detector was characterized and was found to have a detection limit of 4 micro-molar for tryptophan, 22 micro-molar for tyrosine and 500 micro-molar for phenylalanine. Bovine serum albumin, a serum protein with 3 tryptophan residues in its amino acid sequence was also used to characterize the detector. It was ...


Analysis Of Clinically Important Compounds Using Electrophoretic Separation Techniques Coupled To Time-Of-Flight Mass Spectrometry, Zlatuse Durda Peterson Apr 2004

Analysis Of Clinically Important Compounds Using Electrophoretic Separation Techniques Coupled To Time-Of-Flight Mass Spectrometry, Zlatuse Durda Peterson

Theses and Dissertations

Capillary electrophoretic (CE) separations were successfully coupled to time-of-flight mass spectrometric (TOFMS) detection for the analysis of three families of biological compounds that act as mediators and/or indicators of disease, namely, catecholamines (dopamine, epinephrine, norepinephrine) and their O-methoxylated metabolites (3-methoxytyramine, norepinephrine, and normetanephrine), indolamines (serotonin, tryptophan, and 5-hydroxytryptophan), and angiotensin peptides. While electrophoretic separation techniques provided high separation efficiency, mass spectrometric detection afforded specificity unsurpassed by other types of detectors.

Both catecholamines and indolamines are present in body fluids at concentrations that make it possible for them to be determined by capillary zone electrophoresis coupled to TOFMS without employing ...


Energetics Of Ion-Protein Interactions, Travis Tyson Waldron Jan 2004

Energetics Of Ion-Protein Interactions, Travis Tyson Waldron

Theses and Dissertations

In keeping with the goals of our laboratory, efforts in this thesis are directed towards improving our understanding, and therefore our ability to calculate, the energetics of protein-ligand interactions. Electrostatic contributions to protein-ligand binding events are poorly understood, and underrepresented in data sets used to parameterize the energetics of protein unfolding and binding. Therefore, the focus in this thesis is placed on ion-protein interactions as model systems that can give insight into the contribution of charge-charge interactions to the enthalpy, entropy, and heat capacity changes associated with binding. In order to measure the energetics of charge-charge interactions, both differential scanning ...


Energetic Consequences Of Structural Features And Dynamics Changes Upon Nucleotide Binding To Ribonuclease Sa: Molecular Basis For Nucleotide Binding Specificity, Greta Lynn Schrift Jan 2004

Energetic Consequences Of Structural Features And Dynamics Changes Upon Nucleotide Binding To Ribonuclease Sa: Molecular Basis For Nucleotide Binding Specificity, Greta Lynn Schrift

Theses and Dissertations

Proteins are often able to distinguish between closely related ligands, thus achieving specificity. A major goal in biophysical chemistry is to understand the molecular basis for protein-ligand recognition. This level of understanding is necessary for developing methods to accurately predict protein-ligand binding energetics from structural data. The goal of this thesis was to identify features of protein-ligand interactions that may not be adequately accounted for in structure energetics calculations in order to improve our ability to predict binding energetics for these interactions. Specifically, the features of protein-nucleotide binding were studied using the small, guanine-specific ribonuclease, RNase Sa binding to two ...


Strategies For Modifying The Genomes Of Alternate Adenoviral Serotypes To Allow Growth In Per.C6[Superscript Tm] Cells, Nancy M. Dougherty Jan 2004

Strategies For Modifying The Genomes Of Alternate Adenoviral Serotypes To Allow Growth In Per.C6[Superscript Tm] Cells, Nancy M. Dougherty

Theses and Dissertations

No abstract provided.