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Articles 1 - 30 of 32
Full-Text Articles in Physical Sciences and Mathematics
Optimization Of Polymer Separation By Gradient Polymer Elution Chromatography, Gideon R. Liem, Linda Nien-Hwa Wang
Optimization Of Polymer Separation By Gradient Polymer Elution Chromatography, Gideon R. Liem, Linda Nien-Hwa Wang
The Summer Undergraduate Research Fellowship (SURF) Symposium
High Performance Liquid Chromatography (HPLC) has been a versatile separation method for polymers for many years. Analysis of different polymers by HPLC is typically done by utilizing the differential solubility of the polymers by mixing a good solvent and an anti-solvent in various compositions. This method is called Gradient Polymer Elution Chromatography (GPEC). While GPEC has been used extensively, it commonly uses a linear gradient to separate components. Linear solvent gradients consume a lot of solvent and take a relatively long time (> 30 minutes) to complete. The goal of this study is to develop a step gradient from a …
Investigating Intermolecular Interactions In Crystalline Aspirin Using Cdft, Nicholas Turner, Tonglei Li, Mingtao Zhang
Investigating Intermolecular Interactions In Crystalline Aspirin Using Cdft, Nicholas Turner, Tonglei Li, Mingtao Zhang
The Summer Undergraduate Research Fellowship (SURF) Symposium
Drugs today are widely administered in their crystalline form, namely via tablets and capsules. The crystal structure of a drug molecule affects important drug qualities such as solubility, bioavailability, shelf life, and compaction properties. In order to form a basis for crystal structure prediction, it is necessary to first understand how intermolecular interactions cause molecules to pack in certain ways. Being able to predict and perhaps even control a drug molecule’s crystal structure will lead to the development of higher quality drugs that perform more consistently. Scientists and engineers do not fully understand the reasons for a molecule assuming a …
Investigation Of Major Intermolecular Interactions In 7,8-Dihydrobenzo(K)Phenanthridin-6(5h)-One Crystal Using Quantum Calculations And Crystallographic Visualization Programs, Zhiwei Liao, Tonglei Li, Mingtao Zhang
Investigation Of Major Intermolecular Interactions In 7,8-Dihydrobenzo(K)Phenanthridin-6(5h)-One Crystal Using Quantum Calculations And Crystallographic Visualization Programs, Zhiwei Liao, Tonglei Li, Mingtao Zhang
The Summer Undergraduate Research Fellowship (SURF) Symposium
Currently, tablets and capsules are the most common ways of delivering drugs. The active pharmaceutical ingredients and excipients used to make those tablets and capsules are in their crystalline form generally. However, a single molecule can form multiple different crystal structures because of different packing arrangements of the molecules. These different crystal structures have identical chemical composition but different properties such as solubility, density, stability, etc. This phenomenon is called polymorphism. Occurrence of polymorphism could be a disaster for both patients and pharmaceutical companies, as the drug could lose its efficacy due to changes in properties. Studying intermolecular interactions in …
Spectroscopic And Kinetic Study Of Copper-Exchanged Zeolites For The Selective Catalytic Reduction Of Nox With Ammonia, Shane Adam Bates
Spectroscopic And Kinetic Study Of Copper-Exchanged Zeolites For The Selective Catalytic Reduction Of Nox With Ammonia, Shane Adam Bates
Open Access Dissertations
The recent application of metal-exchanged, small-pore zeolites for use in the selective catalytic reduction (SCR) of NOx with ammonia NH3 for automotive deNOx applications has been a great stride in achieving emission standard goals. Copper-exchanged SSZ-13 (Cu-SSZ-13), the small-pore zeolite in this study, has been shown to be very hydrothermally stable and active under conditions presented in the exhaust of the lean-burn diesel engine. In this work, detailed studies were performed to identify many aspects of the active site(s) in Cu-SSZ-13 in order to learn about the standard SCR mechanism.
A series of seven Cu-SSZ-13 samples were …
Influence Of Cholesterol And Bilayer Asymmetry On Membrane Protein Distribution In Polymer-Tethered Raft-Mimicking Lipid Membranes, Noor Fueza Hussain
Influence Of Cholesterol And Bilayer Asymmetry On Membrane Protein Distribution In Polymer-Tethered Raft-Mimicking Lipid Membranes, Noor Fueza Hussain
Open Access Dissertations
It is now widely recognized that lipid rafts, which are membrane domains enriched in cholesterol (CHOL) and sphingolipids (SL), play a significant functional role in the plasma membrane. Raft domains particularly affect membrane functionality by causing sequestering of membrane proteins. Underlying mechanisms of raft-associated membrane protein sequestration remain elusive, due to the complexity, transient nature, and small size of raft domains in cellular membranes. To address these challenges, this dissertation unveils the relationship between lipid raft composition and membrane protein sequestration and function using raft-mimicking model membrane mixtures comprised of coexisting liquid-ordered (lo) and liquid-disordered (ld) domains with reconstituted membrane …
The Effect Of Composition On The Linear And Nonlinear Mechanical Properties Of Particulate Filled Elastomers, Oluwaseyi Ogebule
The Effect Of Composition On The Linear And Nonlinear Mechanical Properties Of Particulate Filled Elastomers, Oluwaseyi Ogebule
Open Access Dissertations
Engineering elastomers are materials capable of undergoing large deformation upon load application and recovering upon load removal. From car tires to building vibration isolator systems, elastomers are the most versatile of engineering materials. The inclusion of particulate fillers into elastomers enhances their mechanical properties (modulus, tensile strength, toughness, tear resistance, etc) thereby extending their applicability to more demanding functions. The automotive, healthcare, construction, adhesives and consumer products are some of the many industries that produce finished goods containing elastomeric parts.
Despite the various concepts on reinforcement in filled elastomers, a complete understanding of their linear viscoelastic properties and the nonlinear …
Construction And Demonstration Of A Tandem Mass Spectrometer Based Instrument For Cold Ion Spectroscopy, James Gerhardt Redwine
Construction And Demonstration Of A Tandem Mass Spectrometer Based Instrument For Cold Ion Spectroscopy, James Gerhardt Redwine
Open Access Dissertations
A new instrument incorporating ion trap based tandem mass spectrometry and cold ion UV and UV-IR double resonance spectroscopy has been developed at Purdue University for the study of gas phase, biologically relevant ions. The instrument incorporates multiple quadrupole linear ion trap mass analyzers to prepare and isolate the precursor ions as well as to analyze the resultant photofragments. A 22-pole ion trap cooled to 5 K via a closed cycle helium cryostat is used to cool the ions for spectroscopic interrogation. Results show the vibrational and rotational temperature of a wide assortment of ions to be 12±2 K.
The …
Continued Progress Towards Efficient Syntheses Of Cephalostatin North 1 Analogs, Daniel Preston Jamieson
Continued Progress Towards Efficient Syntheses Of Cephalostatin North 1 Analogs, Daniel Preston Jamieson
Open Access Dissertations
Jamieson, Daniel P. Ph.D., Purdue University, December 2013. Continued Progress Towards Efficient Syntheses of Cephalostatin North 1 Analogs. Major Professor: PhilipL. Fuchs.
The cephalostatins and ritterazines represent an intriguing class of marine natural products in both structure and biological activity, and the progress towards the synthesis of high valued analogs with a focus on process orientated methodology is described herein. Included in the pages to follow, is the further advancement of the `Red-Ox' strategy toward the highly efficient synthesis of 25-epi-4,15-dihydro-North 1, Chapter 2. A short review focusing on the earlier efforts toward the main synthetic challenges of North 1 …
Elucidation Of Chiral Recognition Mechanisms Of Solutes By Amylose Tris[(S)-Alpha-Methylbenzylcarbamate] Sorbent, Hung-Wei Tsui
Elucidation Of Chiral Recognition Mechanisms Of Solutes By Amylose Tris[(S)-Alpha-Methylbenzylcarbamate] Sorbent, Hung-Wei Tsui
Open Access Dissertations
Enantioselective separations of chiral molecules are important in various chemical fields, such as pharmaceuticals and agrochemicals industries. Polysaccharide-based sorbents have been widely used in chiral liquid chromatography. The recognition mechanisms which determine their enantioselectivities are not completely understood.
In this dissertation, the chiral recognition mechanisms of a widely used commercial sorbent, amylose tris[(S)-alpha-methylbenzylcarbamate], for benzoin (B) enantiomers were first studied. The HPLC data for benzoin with pure n-hexane as the mobile phase have been obtained. The behavior of sorbent-solute-hexane systems can be interpreted by considering only sorbent solute two-component interactions. Infrared (IR) spectra showed evidence of substantial hydrogen bonding (H-bonding) …
Design, Synthesis, And Evaluation Of Molecular Inhibitors For Biologically Relevant Enzymes, Sarah Emma St. John
Design, Synthesis, And Evaluation Of Molecular Inhibitors For Biologically Relevant Enzymes, Sarah Emma St. John
Open Access Dissertations
The work in this thesis details the design, synthesis, and biological evaluation of molecular inhibitors for the inhibition of biologically relevant enzymes. The first three chapters of this thesis concern the polyphenol resveratrol and its inhibition of the quinone reductase 2 (QR2) enzyme. The work on this subject resulted in the complete design, synthesis, biological and structural evaluation of a second generation library of resveratrol analogues. From this work we identified a novel resveratrol analogue that inhibits QR2 in a previously unknown binding orientation. The fourth chapter of this thesis details the de novo design of molecules for the inhibition …
Utilization Of Biomass Derived Furans In Value-Added Organics And Heterogeneous Oxorhenium Catalysts For Deoxydehydration Of Diols, Benjamin L. Wegenhart
Utilization Of Biomass Derived Furans In Value-Added Organics And Heterogeneous Oxorhenium Catalysts For Deoxydehydration Of Diols, Benjamin L. Wegenhart
Open Access Dissertations
As fossil fuels are depleted, there is a growing focus on renewable chemicals based on biomass materials, including both fuels and chemical feedstocks. Current methods for biomass utilization include biological conversion to produce ethanol and various thermochemical routes (gasification, pyrolysis, liquefaction, hydrothermal treatment, etc.). Furfural is one particular chemical that can be obtained from lignocellulosic biomass in good yields through the dehydration of sugar residues. It can be used as a feedstock for chemicals such as furan and THF, or as a platform molecule for making liquid fuels. The objective of this research is to investigate new pathways for the …
Instrumentation, Applications And Fundamentals Of Plasma Ionization Of Organic Molecules From Surfaces, Joshua Scott Wiley
Instrumentation, Applications And Fundamentals Of Plasma Ionization Of Organic Molecules From Surfaces, Joshua Scott Wiley
Open Access Dissertations
Various aspects of the interaction of low-temperature plasma (LTP) ambient ionization with organic molecules and surfaces are discussed. As an application, LTP-MS has been used for the analysis of pesticides directly from fruits and vegetables revealing low parts per billion limits of detection (LODs). Due to low power and gas requirements, a battery-operated and handheld LTP probe was developed for the point-and-shoot MS analyses. Handheld LTP was compared with large-scale LTP on a benchtop and miniature MS revealing similar LODs for both. Long-distance ion transport up to one meter was also demonstrated with flexible tubing for non-proximate sample interrogation. Fundamentals …
Gas-Phase Covalent And Non-Covalent Ion/Ion Chemistry Of Biological Macromolecules, John Robert Stutzman
Gas-Phase Covalent And Non-Covalent Ion/Ion Chemistry Of Biological Macromolecules, John Robert Stutzman
Open Access Dissertations
Gas-phase ion/ion chemistry involves the interaction of oppositely charged ions inside of the mass spectrometer. During this gas-phase chemistry, particle transfer (i.e., proton and electron) or synthesis can occur at rapid reaction rates. Particle transfer represents a mature area of ion/ion chemistry, while selective covalent modification represents a fairly new area of gas-phase chemistry. Gas-phase covalent chemistry is based on traditional solution phase organic chemistry.
The work demonstrated in this dissertation greatly involves gas-phase covalent and non-covalent Schiff base chemistry on peptide and protein ions. The reagent dianion, 4-formyl 1,3-benzene disulfonic acid, has been used to covalently modify unprotonated primary …
Development Of Quantitative Ft- Ir Methods For Analyzing The Cure Kinetics Of Epoxy Resins, Sang Ha Son
Development Of Quantitative Ft- Ir Methods For Analyzing The Cure Kinetics Of Epoxy Resins, Sang Ha Son
Open Access Dissertations
Epoxy thermosets are important engineering materials with applications in coating, adhesives, packaging and as structural components in a variety of advanced engineering products. The ultimate performance of polymer critically depends upon the details of the cure chemistry used to produce the thermoset. In order to better understand and monitor the cure chemistry, quantitative analysis of the FT-IR response has been developed for describing the epoxy-amine curing reaction as well as monitoring the hydrogen bonding that occurs in these systems The FT-IR analysis includes (i) quantitative deconvolution of complex peaks into individual spectral contributions, (ii) peak identification via DFT analysis and …
Preparation Of Mesoporous Silica Supported Ruthenium Oxides And The Application And Kinetic Study In The Catalysis Of Water Oxidation, Yang Zhang
Open Access Dissertations
Photo-induced water splitting of water into H2 and O2 has been a major focus in the development of clean and renewable energy. The development of viable and efficient catalysts that facilitates O2 production remains the major challenge in the study of the corresponding half-reaction of water oxidation. There are plenty of metal oxides reported active in the catalysis of water oxidation. However, several important performance bench marks of those materials, such as the non-stoichiometric production of O2, slow reaction rate and/or low quantum efficiency, remain to be improved.
Ruthenium oxide (RuO2) has long been known as one of the most …
Development Of Isotags For Nmr Based Metabolite Profiling And Applications, Fariba Tayyari
Development Of Isotags For Nmr Based Metabolite Profiling And Applications, Fariba Tayyari
Open Access Dissertations
NMR spectroscopy is a powerful analytical tool for both qualitative and quantitative metabolite profiling analysis. However, accurate quantitative analysis of biological systems especially using one dimensional NMR has been challenging due to signal overlap. In contrast, the enhanced resolution and sensitivity offered by chemoselective isotope tags have enabled new and enhanced methods for detecting hundreds of quantifiable metabolites in biofluids using NMR spectroscopy or mass spectrometry. In this thesis we show improved sensitivity and resolution of NMR experiments imparted by 15N and 13C isotope tagging which enables the accurate analysis of plasma metabolites. To date, isotope tagging has been used …
Synthesis Of Novel Isoprenoid Diphosphate Analogs As Chemical Tools To Investigate Protein Geranylgeranylation, Kayla Jo Temple
Synthesis Of Novel Isoprenoid Diphosphate Analogs As Chemical Tools To Investigate Protein Geranylgeranylation, Kayla Jo Temple
Open Access Dissertations
Many proteins require prenylation in order to be biologically functional. Some such proteins include the small Ras and Rho GTPase superfamilies, nuclear lamins A and B, and the kinesin motor proteins CENP-E and F. Prenyltransferase (PTase) inhibition is currently being explored as a possible treatment not only for cancer but for a wide variety of other diseases.
Clinical studies revealed that the effectiveness of farnesyltransferase inhibitors (FTIs) to treat Ras-dependent tumors is determined by which isoform of Ras is overactive. Unfortunately the majority of Ras-dependent tumors have a mutation in either the N- or K-Ras isoforms; both of these isoforms …
Implementation Of A Research-Based Lab Module In A High School Chemistry Curriculum: A Study Of Classroom Dynamics, Matthew Pilarz
Implementation Of A Research-Based Lab Module In A High School Chemistry Curriculum: A Study Of Classroom Dynamics, Matthew Pilarz
Open Access Dissertations
Pilarz, Matthew. Ph.D., Purdue University, December 2013. Implementation of a Research-Based Lab Module in a High School Chemistry Curriculum: A Study of Classroom Dynamics. Major Professor: Gabriela C. Weaver.
For this study, a research-based lab module was implemented in two high school chemistry classes for the purpose of examining classroom dynamics throughout the process of students completing the module. A research-based lab module developed for use in undergraduate laboratories by the Center for Authentic Science Practice in Education (CASPiE) was modified and implemented in two high school settings. This module consisted of four phases: Skill Building, Experimental Design, Independent Research, …
Silica Colloidal Crystals As Emerging Materials For The High-Throughput Sizing Of Proteins By Packed Capillary Electrophoresis, Nadine K. Njoya
Silica Colloidal Crystals As Emerging Materials For The High-Throughput Sizing Of Proteins By Packed Capillary Electrophoresis, Nadine K. Njoya
Open Access Dissertations
Protein heterogeneity is currently one of the leading problems in formulation of therapeutic proteins. The effectiveness of therapeutic proteins is diminished when they exhibit heterogeneity due to aggregates and degradation by-products. Furthermore, guidelines set forth by the FDA require therapeutic proteins to have high stability as well as high purity. With development time on the order of years and costs incurred in the millions, pharmaceutical companies are investing more time in finding fast and efficient ways to screen for protein heterogeneity. Current methods such as native polyacrylamide gel electrophoresis (PAGE), size-exclusion chromatography (SEC) and capillary electrophoresis (CE) are time consuming, …
Utilizing Electron Microscopy And Spectroscopy Methods To Understand Water Structure And Water Doping, Lior Miller
Utilizing Electron Microscopy And Spectroscopy Methods To Understand Water Structure And Water Doping, Lior Miller
Open Access Dissertations
Water is the second most common element in the universe and the most studied material on earth. Most of the studies concerning water are from the fields of chemistry and biology. Hence, the structure of water molecules and short range order and interactions are well characterized and understood. However, the collective arrangement of water molecules and the long range order are still missing. Understanding of this long range order in water is needed, as it is the key to many water activities.
To fill this gap, this study utilizes a new direct method for characterization of water in the vapor …
Spectroscopic Characterization Of The Water-Oxidation Intermediates In The Ru-Based Catalysts For Artificial Photosynthesis, Dooshaye Moonshiram
Spectroscopic Characterization Of The Water-Oxidation Intermediates In The Ru-Based Catalysts For Artificial Photosynthesis, Dooshaye Moonshiram
Open Access Dissertations
Utilization of sunlight requires solar capture, light-to-energy conversion and storage. One effective way to store energy is to convert it into chemical energy by fuel-forming reactions, such as water splitting into hydrogen and oxygen. Ruthenium complexes are among few molecular-defined catalysts capable of water splitting. Insight into the mechanism of their action will help to design future robust and economically feasible catalysts for light-to-energy conversion. Mechanistic insights about the design of such catalysts can be acquired through spectroscopic analysis of short-lived intermediates of catalytic water oxidation. Development of time-resolved approaches through stopped flow UV-Vis Spectroscopy to follow the catalysis of …
Top-Down Interrogation And Characterization Of Biological Macromolecules, Yang Gao
Top-Down Interrogation And Characterization Of Biological Macromolecules, Yang Gao
Open Access Dissertations
Analytical mass spectrometry has been widely applied in the field of biomolecule identification and characterization. It provides fast, accurate and robust information relevant to the molecular mass, composition and structure of the target analytes.
This thesis is focused on the top-down analysis of various macrobiomolecules, nucleic acids and proteins, in the context of ion/ion reaction and gas-phase unimolecular dissociation. The first part of the thesis deals with gas phase fragmentation behavior of chemically modified oligonucleotides. Factors, such as the observation time-scale, the ion type and the energy deposition method, are explored using a quadrupole/time-of-flight mass spectrometer. Novel fragmentation pathway associated …
Mass Spectrometric Studies On The Primary Products Of Fast Pyrolysis Of Carbohydrates And The Molecular Structures Of Asphaltenes, And The Development Of A Rastering Probe For Laser-Induced Acoustic Desorption Into An Atmospheric Pressure Chemical Ionization Source, Matthew Robert Hurt
Open Access Dissertations
Mass spectrometry (MS) has proven invaluable in the field of mixture analysis and structural elucidation. Tandem mass spectrometry (MS/MS) utilizing collision-activated dissociation (CAD) has become the technique of choice for structural elucidation of unknown analytes in mixtures. When coupled with gas chromatography (GC) or high performance liquid chromatography (HPLC), it allows for trace level analysis of mixture components. In spite of the utility of mass spectrometry in complex mixture analysis, it does have limitations. Traditional GC/MS methods used for the analysis of fast pyrolysis products cannot be used to analyze the primary products, thus limiting the knowledge that can be …
Structural Analysis Of Carbohydrates By Mass Spectrometry, Chiharu Konda
Structural Analysis Of Carbohydrates By Mass Spectrometry, Chiharu Konda
Open Access Dissertations
Protein glycosylation is a highly frequent post-translational modification. Glycosylation is actively involved in intermolecular and intercellular binding events that are important to a wide range of biological functions such as immunity and fertility. The unique functions of glycans are directly related to their structures. In order to fully characterize the structure of an unknown glycan, 5 levels of structural information is needed: sugar unit identity, anomeric configuration, linkage types, sequence, and branching location. One of the grand challenges limiting the advance of glycosciences is the lack of sensitive tools for detailed glycan structural analysis. Tandem mass spectrometry (MS/MS) is a …
Development Of A Field-Portable Miniature Mass Spectrometer Designed For In-Situ Analysis And Ion Trap Miniaturization, Paul Isaac Hendricks
Development Of A Field-Portable Miniature Mass Spectrometer Designed For In-Situ Analysis And Ion Trap Miniaturization, Paul Isaac Hendricks
Open Access Dissertations
Chemical analysis by mass spectrometry has become the gold standard due to the sensitivity, selectivity, and short analysis times that are afforded by the method. Advances in miniaturized vacuum systems, mass analyzers, electronics, and ionization sources have allowed for the development of field-portable mass spectrometers. The performance of portable instruments has received much attention for their utility in the detection of illicit drugs, explosives, environmental contaminants, therapeutic drugs, and more recently, biological tissues. Furthermore, detection of the aforementioned compounds can be completed at atmospheric pressures and in the presence of complex matrices and sample surfaces when used in conjunction with …
Fluorous- Phase Synthesis Of Heparan Sulfate Disaccharides & Low-Molecular Weight Additives For Enhancing The Performance Of Lithium-Ion Batteries., Matthew Daniel Casselman
Fluorous- Phase Synthesis Of Heparan Sulfate Disaccharides & Low-Molecular Weight Additives For Enhancing The Performance Of Lithium-Ion Batteries., Matthew Daniel Casselman
Open Access Dissertations
Heparan sulfate is a complex cell-surface proteoglycan that serves many important roles in biology, such as growth and development, immune response and pathogenesis. Heparan sulfate is structurally heterogeneous due to the variable post- glycosylation modifications, particularly the generation of diverse sets of sulfate esters (sulfoforms) for any given disaccharide unit. In order to establish useful relationships between heparan sulfate structure and biological activity, a set of well-defined sulfoforms is necessary to support binding affinity screening. In this thesis, we describe the generation of diverse sulfoforms from heparan disaccharides using a fluorous tag to facilitate purification of highly charged intermediates, and …
Osmium Catalyzed Dihydroxylation And Oxidative Cleavage Of Vinyl Sulfone And Elucidation Of The Vinylsulfone Polypropionate Methodology For The Synthesis Of The C32 Des-Methyl C28-C34 Actin Binding Tail Of Aplyronine A, Thomas Paul Bobinski
Open Access Dissertations
A general methodology for the generation of dipropionate functionalities using cyclic 7-membered vinylsulfones has been devised for the purpose of synthesizing polyketide natural products such as aplyronine A. Final oxidative cleavage via ozonolysis has been shown to be difficult providing variable yields. Furthermore, elegant synthesis of the C28-C34 segment of the aplyronine A actin binding tail has proved elusive. Utilization of OsO4 and catalytic citric acid has led to a methodology whereby harsh ozonolysis procedures can be mostly avoided. A reengineering of the vinylsulfone polypropionate methodology in conjunction with osmylation has been found to provide the actin binding tail under …
Novel Modulation Of Adenylyl Cyclase Type 2, Jason Michael Conley
Novel Modulation Of Adenylyl Cyclase Type 2, Jason Michael Conley
Open Access Dissertations
Adenylyl cyclase isoforms are distinctly modulated by G protein subunits and are therefore hypothesized to be uniquely regulated by proteins that influence G protein signaling. Activator of G protein signaling 3 (AGS3) is a G protein modulator that binds Gαi subunits in the GDP-bound state, implicating AGS3 as an important regulatorof Gi-coupled receptor signaling. We studied the ability of AGS3 to modulate recombinant adenylyl cyclase(AC) type 1 and 2 signaling in HEK293 cells following both acute and persistent activation of the D 2Ldopamine receptor (D2L DR). AGS3 expression modestly enhanced the potency of acute quinpirole-induced D 2LDR …
Fate Of 17Α-Estradiol, 17Β-Estradiol, And Estrone In Agricultural Soils And Sediments, Michael L. Mashtare Jr
Fate Of 17Α-Estradiol, 17Β-Estradiol, And Estrone In Agricultural Soils And Sediments, Michael L. Mashtare Jr
Open Access Dissertations
The shift to concentrated animal production facilities and increasing rural-urban migration has increased the localized land application of nearly 1 billion tons of manure and biosolids annually. Although these applications provide nutrients and contribute to soil tilth, they also serve as a source for an estimated 49 tons of the natural manure-borne estrogens, 17α-estradiol (17α-E2), 17β-estradiol (17β-E2), and estrone (E1). While these estrogens are critical to endocrine systems, the low concentrations observed in the environment can disrupt endocrine function in non-target organisms, e.g., altering secondary sex characteristics which can lead to changes in wildlife communities.
Research presented here focuses on …
Specific Salt Effects On The Formation And Thermal Transitions Among Β-Lactoglobulin And Pectin Electrostatic Complexes, Stacey Ann Hirt
Specific Salt Effects On The Formation And Thermal Transitions Among Β-Lactoglobulin And Pectin Electrostatic Complexes, Stacey Ann Hirt
Open Access Theses
Factors of ion specificity and ionic strength (I~0-100) were studied in the electrostatic complex formation and protein particle formation by thermal treatment for a β-lactoglobulin and pectin system. ζ-potential showed β-lactoglobulin and pectin began to interact near pH 5.50 and interactions were strengthened with decrease in pH. Visible light turbidimetry and light scattering at 90° revealed a trend in critical pH transitions for electrostatic complex formation based on both the ionic strength and the anion of the salt species, while effects of the monovalent cation was insignificant. Critical pH values for complex formation and separation (pHc and pHΦ) decreased with …