The endogenous hormones estrone and 17β-estradiol support vertebrate growth and development, but slight increases above ambient concentrations may paradoxically induce endocrine disruption, leading to increased frequencies of reproductive disorders and cancer in humans and wildlife. Livestock excrete estrogenic compounds which can lead to surface and groundwater contamination. Limited information exists concerning estrogen fate and transport, as exposure concerns have recently arisen. This study examined the chemical behavior of estrone and 17β-estradiol with the goal of elucidating manure management principles applicable to animal feeding operations (AFOs). Both compounds indicated that they are susceptible to physicochemical and biological decomposition. Photolysis yielded 27- and 35-day half-lives for estrone and 17β-estradiol at pH 7, respectively, based on test conditions. 17β-estradiol photolysis exhibited a slight pH-dependent behavior. Mineralization produced half-lives ranging from 7 to 15 days for estrone and 3 to 7 days for 17β-estradiol. Indigenous microbial populations did not demonstrate a lag phase and therefore appeared to have been well acclimated to degrading these compounds. Anaerobic lagoon supplements did not affect mineralization rates. The compounds had partition coefficients ranging from 2 to 4.4 mL g-1, depending on soil characteristics. Estrone and 17β-estradiol had a higher absorptivity to soils with greater clay content and organic matter. Once sorbed, binding appeared largely irreversible with minimal desorption. Column experiments detected no estrone in the leachate for the finer textured soils, while estrone had completely migrated through the loamy fine sand after 7 pore volumes. Hypothetical scenarios, simulated using HYDRUS-1D, evaluated the combined effects of soil texture and the values obtained for sorption and mineralization on leaching. Model results indicated rapid leaching in loamy sand, while sandy clay loam and clay yielded significantly slower estrone and 17β-estradiol movement with concentrations 1 to 3 orders of magnitude lower. Data suggest that estrogens applied to sandy soil may leach and contaminate groundwater, especially in the presence of shallow water tables. Sandy clay loam and clay likely present minimal risk for subsurface mobility, but simulated accumulation near the soil surface may promote transport via overland flow. Sound manure management practices will likely reduce off-site transport of estrogens originating from AFOs.

The endogenous hormones estrone and 17β-estradiol support vertebrate growth and development, but slight increases above ambient concentrations may paradoxically induce endocrine disruption, leading to increased frequencies of reproductive disorders and cancer in humans and wildlife. Livestock excrete estrogenic compounds which can lead to surface and groundwater contamination. Limited information exists concerning estrogen fate and transport, as exposure concerns have recently arisen. This study examined the chemical behavior of estrone and 17β-estradiol with the goal of elucidating manure management principles applicable to animal feeding operations (AFOs). Both compounds indicated that they are susceptible to physicochemical and biological decomposition. Photolysis yielded 27- and 35-day half-lives for estrone and 17β-estradiol at pH 7, respectively, based on test conditions. 17β-estradiol photolysis exhibited a slight pH-dependent behavior. Mineralization produced half-lives ranging from 7 to 15 days for estrone and 3 to 7 days for 17β-estradiol. Indigenous microbial populations did not demonstrate a lag phase and therefore appeared to have been well acclimated to degrading these compounds. Anaerobic lagoon supplements did not affect mineralization rates. The compounds had partition coefficients ranging from 2 to 4.4 mL g-1, depending on soil characteristics. Estrone and 17β-estradiol had a higher absorptivity to soils with greater clay content and organic matter. Once sorbed, binding appeared largely irreversible with minimal desorption. Column experiments detected no estrone in the leachate for the finer textured soils, while estrone had completely migrated through the loamy fine sand after 7 pore volumes. Hypothetical scenarios, simulated using HYDRUS-1D, evaluated the combined effects of soil texture and the values obtained for sorption and mineralization on leaching. Model results indicated rapid leaching in loamy sand, while sandy clay loam and clay yielded significantly slower estrone and 17β-estradiol movement with concentrations 1 to 3 orders of magnitude lower. Data suggest that estrogens applied to sandy soil may leach and contaminate groundwater, especially in the presence of shallow water tables. Sandy clay loam and clay likely present minimal risk for subsurface mobility, but simulated accumulation near the soil surface may promote transport via overland flow. Sound manure management practices will likely reduce off-site transport of estrogens originating from AFOs.

The purpose of this study was to investigate the carbodiimide-mediated amidation of hyaluronan (HA). The carbodiimide-mediated amidation includes the formation of a urea derivative, O-acylisourea, between the carbodiimide and a carboxylic group of HA, which a primary amine can displace, resulting in an amide bond. Reaction conditions were investigated and optimized, the molecular weights Mn and Mw were determined with size-exclusion chromatography and by-products were analysed with 1H NMR. The reaction is done at room temperature in slightly acidic pH, giving a degree of substitution between 5 to 15 %. A catalyst, N-hydroxysuccinimide, was needed for the coupling to be successful, since O-acylisourea was shown not to be reactive enough towards primary amines. It was found out that dissociated primary amines successfully couple to HA, contrary to what has been suggested before. 1H NMR revealed that O-acylisourea readily forms a by-product, which is covalently attached to HA, through the means of rearrangement. Also, 1H NMR showed that the carbodiimide reacts with phenols. An increase of Mn and Mw compared with native HA was observed and attributed to ester bond formation between a hydroxyl- and carboxylic group of HA polysaccharides. To conclude, the carbodiimide-mediated amidation is an unspecific reaction which is not suited for the coupling of primary amines to HA.

In this dissertation, an electrical discharge coating uses an isolated sleeve to form a closed space between the end surface of electrode and the work to deposit a thin film onto a substrate. The discharge occurs at the location where the two surfaces are closest and the dielectric fluid ionizes at this location to create a path for the discharge. Hence, this closed space is heated to extremely high temperature, so that a small portion of the work surface is suddenly melted with the particles in the dielectric fluid and then coated to increase its coating speed and quality. The electrode material is made of brass, the work material SKD11, and the dielectric fluid is kerosene with the WC powder concentration of 50g/L. The pulse-on and pulse-off times are 25 and 500£gs, respectively. The effects of supply voltage, electrical discharge coating time, electrical discharge gap, and powder added cycle on the coating characteristics are investigated. According to the experimental results, the electrical discharge with isolated sleeve can achieve a complete coating layer onto the surface of work. The coating thickness increases with increasing electrical discharge coating time and gap as the supply voltage is larger than the threshold voltage of electrical discharge. At the supply voltage below 250V and the added powder cycle less than 10, the coating thickness increases with increasing supply voltage and cycle. The quality of coating layer is better at the low gap distance and the high supply voltage. The hardness of coating layer is about HV 1687 which is approximately 5 times of substrate hardness using micro-hardness test. The electrical discharge without isolated sleeve cannot achieve the above-mentioned advantages.

Submitted by Jesiel Ferreira Gomes (jesielgomes@ufcg.edu.br) on 2018-02-19T12:09:48Z No. of bitstreams: 1 Dissertação José Milton Oliveira.pdf: 613927 bytes, checksum: 42f920a8d7524e2725e2f08e00f5222d (MD5) / Made available in DSpace on 2018-02-19T12:09:48Z (GMT). No. of bitstreams: 1 Dissertação José Milton Oliveira.pdf: 613927 bytes, checksum: 42f920a8d7524e2725e2f08e00f5222d (MD5) Previous issue date: 2008 / O Monocloreto de Vinila (MVC) é produzido a partir do craqueamento térmico da molécula de 1,2 dicloroetano (1,2 EDC), sendo que durante este processo endotérmico, a molécula MVC é formada pela remoção de um átomo de hidrogênio e outro de cloro da molécula de 1,2 EDC, que posteriormente se combinam para produzir também uma molécula de ácido clorídrico. Além destes produtos, também ocorre a formação de diversos subprodutos tais como cloropreno, benzeno e substâncias orgânicas com baixo número de átomos de hidrogênio (coque). O coque, por sua vez, ao se depositar ao longo das serpentinas dos fornos de craqueamento é responsável pela: i) Elevação de pressão na carga deste equipamento, influenciada pelo acúmulo de coque e por outros parâmetros, tais como vazões de alimentação de EDC, conversão e, principalmente, temperatura, e/ou ii) Elevação pontual de temperatura, devido à diminuição da condutividade térmica dos tubos da serpentina, causado pelo crescimento da camada de coque. Esses dois parâmetros, intimamente relacionados, são cruciais na determinação da parada de operação dos fornos para a realização da operação de decoque, pois, o depósito de coque afeta a velocidade nos tubos (tempo de residência/conversão), afeta a transferência de calor (temperatura/conversão), entre outros. O efeito da cada agente isoladamente não é conhecido quantitativamente. Um dos caminhos para a aquisição deste conhecimento é a construção de um modelo do processo, confrontando-o com os resultados de uma fornalha industrial. O modelo desenvolvido nesta pesquisa tem como objetivo prever a conversão do 1,2 dicloroetano, proporcionando um melhor acompanhamento do equipamento. O mesmo foi ajustado a partir de dados de processo coletados em unidade industrial. / Vinyl Chloride Monomer (MVC) is produced from the thermal cracking of the 1.2 Dicloroethane (1.2 EDC). The molecule of MVC is formed by the removal an atom of Hydrogen and another of Chlorine of the molecule of 1.2 EDC, that subsequently combine for produce also a molecule of Chloridirc acid. Beyond these products, also occurs the formation of diverse byproducts such as Chloroprene, Benzene and Organic substances with low Hydrogen atoms number (coke). The coke itself deposit into the coil furnace and it is responsible by the: i) Elevation of pressure in feed furnace, influenced by the accumulation of coke and by others parameters, such as feed of EDC, conversion and, mainly, temperature, or ii) punctual Elevation of temperature, due to the diminution of the thermal conductivity of the pipes. These two parameters, intimate related, healthy crucial in the determination of the stop of operation of the ovens for the achievement of the operation of decoke, therefore the deposit of coke affects the speed in the pipes (time of residence/conversion), affects the transference of heat (temperature/conversion), among others. The effect of the each agent isolated is not known quantitative. One of the way for the acquisition of this knowledge is the construction of a model of the trial, confronting it with the results of an industrial furnace. The model developed in this research has like objective foresees the conversion of the 1,2 EDC, providing a better accompaniment of the equipment. The even it was adjusted from facts of trial collected in industrial unit.

Ce travail a été entrepris dans le but de caractériser biochimiquement et biologiquement les collagènes de méduse. l’objectif de notre travail a été d’évaluer ce matériel en vue de sa valorisation pour l’élaboration de biomatériaux à usage médical. dans un premier temps, nous avons optimisé les techniques d’extractions des collagènes de quatre espèces de méduses : rhizostoma pulmo, cotylorhiza tuberculata, pelagia noctiluca et aurelia aurita. l’étude de la stabilité thermique par dichroïsme circulaire des collagènes nous a montré que la température de dénaturation des collagènes de rhizostoma pulmo était de 28,9°c. nous avons choisi de réaliser la réticulation des collagènes de méduse par la méthode des carbodiimides (edc/nhs). cette méthode nous a permis d’augmenter la température de dénaturation jusqu’à 33°c (versus 28,9°c). l’étude de l’interaction entre les cellules d’origine humaine (mg63 et fibroblastes) et les collagènes de méduses, nous a permis de démontrer qu’elles étaient capables d’adhérer aux collagènes de méduses natifs ou dénaturés. des immunomarquages de la vinculine des cellules mg63 et des fibroblastes sur collagènes de méduse natifs ou dénaturés nous ont permis de caractériser les adhésions mises en places par ces deux types cellulaires. l’analyse des milieux de culture des cellules mg63 et des fibroblastes par zymographie sur collagènes de méduse natifs ou dénaturés nous a permis de mettre en évidence que des mmps d’origine humaine, seraient capables de dégrader les collagènes de méduses. nous pouvons dans ce cas estimer que le collagène de méduse serait un bon substrat pour l’élaboration de biomatériaux résorbables / This work was undertaken to characterize biochemically and biologically jellyfish collagen. the aim of our study was to evaluate the material for the development of biomaterials for medical use. initially, we optimized the technical extraction of collagen from four species of jellyfishes: rhizostoma pulmo, cotylorhiza tuberculata, pelagia noctiluca and aurelia aurita. the study of thermal stability by circular dichroism of collagen has shown that the denaturation temperature of rhizostoma pulmo collagens was 28.9 ° c. we chose to achieve crosslinking of collagen of jellyfish by the method of carbodiimides (edc/nhs). this method allowed us to increase the denaturation temperature to 33 ° c (vs. 28.9 ° c). the study of the interaction between human cells (mg63 and fibroblasts) and jellyfish collagen, demonstrated that they were able to adhere native or denatured jellyfish collagen. the immunostains of vinculin of mg63 cells and fibroblasts seeded on native or denatured jellyfish collagen, allowed us to characterize the focal adhesions of these two cell types. analysis of culture media of mg63 cells and fibroblasts by collagen zymography on native or denatured jellyfish collagen gels, allowed us to demonstrate that mmps of human origin, are able to degrade jellyfish collagen. we estimate in this case that the jellyfish collagen is a good substrate for the development of resorbable biomaterials

A study to optimise an IgG based immunosensor is presented, that has been carried out by absorbing monolayers to a gold transducer surface at varying immersion times and temperatures. The theory and kinetics of monolayer adsorption are analysed and discussed. Existing mathematical models are reviewed and experimentally researched, to highlight gaps in knowledge that would facilitate high quality, cost effective immunosensor production. The creation of two mathematical models to predict monolayer adsorption kinetics and optimal immersion times are discussed. Details are provided of how the new mathematical models may be advanced, and how the production of immunosensors may be further improved. The first novel mathematical model (PTCS) has been created to model the presence of two sequentially forming structures on the surface of a substrate. It gives an insight into the percentages of each structure on the surface, along with the actual adsorption process. This model provides a good fit to all applicable experimental data and has allowed the deduction of optimum immersion times. The second novel model (PIF) provides a greater insight than existing models into the individual contributions to surface coverage by both random and island growth. This allows an insight into how the monolayer surface is covered, which is critical to determine the optimum conditions for adsorption. This model also provides a good fit to the isotherm data it has been applied to. To provide a thorough understanding of the bulk properties of monolayer formation over the gold transducer, and how these properties vary with immersion time and temperature, various measurement techniques have been employed. Electrochemical Impedance Spectroscopy (EIS) has been the principle measurement technique used to measure the bulk properties, but confirmation studies have also been carried out including, Contact angle measurements, FTIR microscopy with BSA molecular labels, Fluorescence microscopy for small adsorbed molecules and AFM for layers assembled from macromolecules. The data generated from the different techniques show consistency with the arguments discussed in each instance. Two different IgG adsorption processes have been compared. These include direct IgG addition and a multilayered streptavidin-based process. The results indicate that IgG molecules adsorbed via the streptavidin based multilayer process are more vertically orientated and have a higher packing density of IgG molecules. Keywords: Self Assembled Monolayer, impedance-based immunoassay, Streptavidin, biotinylated IgG, mathematical adsorption modelling.

Thesis (M.Ing. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2007.

The pharmaceutical industry is spending more and more on Research and Development (R&D) every year. In addition, these R&D costs are increasing at a faster rate than sales. In order to resolve this dilemma a significant increase in R&D productivity is required. One of the main contributions to these R&D costs is the acquisition of data during clinical trials. The most important objective of a clinical trial is the collection of high quality data. No matter how well a clinical trial is conducted, if the data quality is poor, a meaningful analysis is not possible. The data acquisition method therefore plays a significant role in the overall outcome of a clinical trial. In this study a Mobile Clinical Data Acquisition System (MCDAS) was developed for the electronic collection of high-quality Patient-Reported Outcome (PRO) data. The system consisted of a cellular phone based electronic Diary (eDiary) for capturing data, and a website for administering the collected data. The system was designed so that it could be implemented on any clinical trials, no matter what data was collected. The MCDAS was successfully implemented on two clinical trials. The study shows that electronically capturing clinical data improves the quality of data obtained, thereby reducing the time and costs associated with clinical trials. / Thesis (M.Ing. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2007.

The pharmaceutical industry is spending more and more on Research and Development (R&D) every year. In addition, these R&D costs are increasing at a faster rate than sales. In order to resolve this dilemma a significant increase in R&D productivity is required. One of the main contributions to these R&D costs is the acquisition of data during clinical trials. The most important objective of a clinical trial is the collection of high quality data. No matter how well a clinical trial is conducted, if the data quality is poor, a meaningful analysis is not possible. The data acquisition method therefore plays a significant role in the overall outcome of a clinical trial. In this study a Mobile Clinical Data Acquisition System (MCDAS) was developed for the electronic collection of high-quality Patient-Reported Outcome (PRO) data. The system consisted of a cellular phone based electronic Diary (eDiary) for capturing data, and a website for administering the collected data. The system was designed so that it could be implemented on any clinical trials, no matter what data was collected. The MCDAS was successfully implemented on two clinical trials. The study shows that electronically capturing clinical data improves the quality of data obtained, thereby reducing the time and costs associated with clinical trials. / Thesis (M.Ing. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2007.