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Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Aircraft-Based Measurements For The Identification And Quantification Of Sources And Sinks In The Carbon Cycle, Dana R Caulton
Aircraft-Based Measurements For The Identification And Quantification Of Sources And Sinks In The Carbon Cycle, Dana R Caulton
Open Access Dissertations
Improved quantification of carbon-cycle sources and sinks is an important requirement for determining mitigation strategies and modeling future climate interactions. Analytically robust measurements require high-precision instrumentation and thoughtful experimental design to produce rigorous and reproducible results despite complex and quickly changing meteorological and environmental conditions. Here, an aircraft platform equipped with a high-precision cavity ring-down spectrometer for CO2, CH4 and H2O quantification was used to acquire data from previously un-sampled sources. The aircraft mass-balance technique was used to quantify CH4 emissions from natural gas well pads in the drilling stage, which were 2-3 orders of …
New Strategies To Reveal Protein Candidates In Protein-Protein Interactome Study, Meng-Chieh Chen
New Strategies To Reveal Protein Candidates In Protein-Protein Interactome Study, Meng-Chieh Chen
Open Access Theses
Comprehensive protein-protein interaction network analysis can help reveal protein functions in a system-wide manner. A reliable knowledgebase of interaction networks is not only important for selecting the candidates for drug therapies, but also for evaluating the disease risk. In current interaction databases, 322579 interactions comprised of 56460 proteins have been reported (statistical analysis from APID: Agile Protein Interaction DataAnalyzer; http://bioinfow.dep.usal.es/apid/index.htm). The huge datasets are contributed mainly by yeast -two -hybrid (Y2H) screening and affinity-purification followed by mass spectrometry (AP-MS). High false positive rates and failing to cover certain interaction categories are the limitations of these two methods. Here, we developed …
Reverse-Phase Liquid Chromatography Of Small Molecules Using Silica Colloidal Crystals, Natalya Khanina
Reverse-Phase Liquid Chromatography Of Small Molecules Using Silica Colloidal Crystals, Natalya Khanina
Open Access Theses
Capillaries packed with a silica colloidal crystal (SCC) of 470 nm nonporous particles have recently been shown to offer significant improvements in the peak width, resolution, and speed of protein analysis due to the reduction of the A and C term broadening contributions of the Van Deemter equation. While protein separations using this technology have shown vast improvements, small molecules remain largely unexplored. As the SCC allows for an approximately diffusion limited system, extremely high plate numbers are expected for small molecule separations. The research presented herein studies the feasibility of pressure-driven small molecule separation using SCCs and commercial instrumentation. …
Metal-Protein Interactions For Proteomics Applications, Keerthi B Jayasundera
Metal-Protein Interactions For Proteomics Applications, Keerthi B Jayasundera
Open Access Dissertations
In the quest of deciphering biological mechanisms, the understanding of proteins and their functions is a vital component. However the complexity of the proteome poses an immense challenge for analytical chemists to explore it comprehensively. Currently mass spectrometry is at the forefront of proteome analysis, providing great capabilities to couple with modern separation techniques for wide applications. One major objective of current proteomic technologies is to identify proteins of interest among high background, in particular from complex biological samples. A variety of techniques have been developed over the years to simplify protein samples, which are broadly classified as enrichment, high …
Gas-Phase Ion/Ion Reactions Of Biomolecules: An Examination Of Carboxylate Reactivity And Arginine Based Non-Covalent Complexes, Nathan Zachary Barefoot
Gas-Phase Ion/Ion Reactions Of Biomolecules: An Examination Of Carboxylate Reactivity And Arginine Based Non-Covalent Complexes, Nathan Zachary Barefoot
Open Access Theses
The advent of Electrospray Ionization with the ability to generate multiply charges ions has contributed significantly to the study of gas-phase ion/ion reactions. With the tools available in mass spectrometry it has been shown that these reactions are effective at transforming one type of gaseous ion into another through a series of reactions. This work examines some of these reactions and their application to field of proteomics specifically focusing on the amino acids of arginine and lysine. NHS reagents have been shown to react to both of these molecules with in the gas-phase under different conditions but have relies on …
Separation Of On-Column Labeled Model Proteins With Packed Capillary Electrophoresis, Yingxu Hao
Separation Of On-Column Labeled Model Proteins With Packed Capillary Electrophoresis, Yingxu Hao
Open Access Theses
Protein drugs are increasingly developed in the pharmaceutical company. Under the regulation of FDA, high purity of therapeutic proteins needs to be maintained. Before putting those drugs in the market, fast and efficient method is in need to achieve homogeneity. Traditionally, polyacrylamide gel electrophoresis (PAGE), capillary electrophoresis (CE), and size-exclusion chromatography (SEC) are used for the purification process. These methods have the disadvantages of low time and cost efficiency, and this quality assurance process has become the bottleneck of production. In our group, sub-micron silica colloidal particles with polyacrylamide layer on the surface are packed inside capillaries to increase the …
Physical And Chemical Attributes Of A Genetically Modified Fruit Pectin, Carl Patrick Littrell
Physical And Chemical Attributes Of A Genetically Modified Fruit Pectin, Carl Patrick Littrell
Open Access Theses
Pectin is an important polymer used in the food industry as a thickening and gelling agent. Though pectin is ubiquitous in plants, chemical and structural differences among pectin molecules prevent most from being viable for industrial use. Enzymes found naturally in fruit cell walls during the ripening process impair many desirable attributes of fruit pectins, rendering them unsuitable for industrial applications. Pectin methylesterase (PME) is one such enzyme whose expression can be altered during ripening through the use of recombinant genetic engineering. Reduction in levels of PME results in increased degree of methylation and molecular size of pectin, greatly increasing …
Investigation Into The Control Of Melittin Secondary Structure And Antimicrobial Activity, Zachary B. Molinets
Investigation Into The Control Of Melittin Secondary Structure And Antimicrobial Activity, Zachary B. Molinets
Open Access Theses
Antimicrobial resistance has been an exponentially growing problem since the discovery of antibiotics. Antibiotics have been misused for many years and this misuse has grown into a real problem for the medical community. While there are countless safeguards to prevent infection by a resistant strain of bacteria, there are still many plagued by it and must be treated with sometimes dangerous antibiotics. Melittin, along with many other peptides, contain potent antimicrobial properties, but are also toxic toward enthrocytes. The control of the secondary structure of peptides provides the key to adjusting their activity.
Synthesis And Characterization Of Crystalline Iron Nanoparticles From Zerovalent Iron Sandwich Complexes, Anh Tue Nguyen
Synthesis And Characterization Of Crystalline Iron Nanoparticles From Zerovalent Iron Sandwich Complexes, Anh Tue Nguyen
Open Access Theses
In this project we present a systematic study on the synthesis of crystalline iron nanocubes by thermal decomposition of an iron sandwich complex, ( π-C5H5)Fe0(π-C 6H7), in the presence of oleylamine and oleylamine.HCl as surfactants and n-decane as a solvent. The presence of oleylamine.HCl is essential for the reproducible formation of crystalline iron cores.^ Reaction parameters such as temperature, surfactant concentration, effect of counterion, and organoiron reagent structure were investigated in order to obtain iron nanoparticles with uniform size and shape. The nanoparticles, which were characterized by …
Reactivity Studies Of Tridhydropyridine Radical Cautions By Using Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry And Advancement Of Mass Spectrometric Analysis Of Asphaltenes And Degradation Products, Mohammad Sabir Aqueel
Open Access Dissertations
Aromatic organic molecules which have unpaired electrons play an important role in a variety of applications in the fields of organic synthesis, organic magnets, and biological activity of organic compounds. Several studies have been published on σ- type carbon-centered mono- and biradicals. Reactive intermediates with three formally unpaired electrons are known as triradicals. They can be defined as species with three electrons distributed in three degenerate or nearly degenerate orbitals, based on Salem's definition of biradicals from the electronic structure point of view. Very little is known about the reactivity of carbon-centered σ,σ,σ- triradicals due to the complexity of studying …
Protein Affinity Extraction Of Prostate Specific Antigen (Psa) Using Submicron Spheres, Yao Wang
Protein Affinity Extraction Of Prostate Specific Antigen (Psa) Using Submicron Spheres, Yao Wang
Open Access Theses
PSA has been used as a biomarker for prostate cancer for a long time. To characterize different glycoforms of PSA using techniques like UHPLC and cIEF, concentration and purification of PSA from complex samples becomes necessary. Our group has developed submicron silica spheres based affinity beads to extract PSA through immunoprecipitation. This study focuses on measuring the bead performance when antibody type/amount was varied and PSA concentration was lowered for clinical use. To better satisfy the requirement of large-scale extraction, several attempts were made to increase the bead capacity. The results will be presented and future directions of the project …