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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The separation technique for nonlinear partial differential equations : General results and its connection with other methods

Malloki, I. A. January 1987 (has links)
No description available.
2

Analyses of spermatozoa surface proteins using different separation techniques

Fortuin, Kay Arlene January 2013 (has links)
Magister Scientiae (Medical Bioscience) - MSc(MBS) / Passage of spermatozoa through the female reproductive tract is essential for the regulation of fertilization, ensuring that healthy sperm reach the oocyte. Previous studies were devoted to morphological selection of sperm cells by the cervical mucus. However, research prove that the loss of integrity of the sperm plasma membrane is associated with infertile men, irrespective of their normal semen parameters. This indicates that the sperm plasma membrane plays an important role in fertilization. Further studies indicated that sperm surface proteins assist penetration through the female reproductive tract and would therefore provide useful insight in understanding other factors associated with male infertility. The aim of this project was to determine if there are any differences between sperm surface proteins of fertile donor samples in relation to infertile patient samples using different separation techniques and different detergents. Three different sperm separation techniques were employed, including wash, swim-up (SU) and Percoll density gradient centrifugation (DGC).Parallel to this, the deoxy-ribose nucleic acid (DNA) fragmentation of these cells were analysed for comparison of the extent of DNA damage induced due to different separation techniques used. This provided evidence that the best separation technique is the DGC as it minimises the amount of DNA fragmentation caused. Four different detergents were used in the process of extracting the membrane proteins from spermatozoa, namely sodium dodecyl sulphate (SDS), saponin,cetyl-trimethyl-ammonium bromide (CTAB), and TWEEN-20. The membrane proteins were then separated on a12% SDS poly-acrylamide gel electrophoresis (PAGE), and analysed by Coomassie blue and silver staining techniques as well as densitometry. Due to the different chemical nature of the detergents that extracted different surface proteins, CTAB (cationic) and SDS (anionic) extracted the most because of its strong solubilising abilities as non-ionic detergents. Common proteins that were extracted in donor samples included; 115, 92.5, 89, 61, 55.5, 51.5, 47, 44.5, 43, 38.5, 34 and 28 kDa proteins. In patients, commonly occurring proteins included; 92.5, 74.5, 70, 60.5, 51.5, 50, 44.5, 43, 36, 29.5, and 25.5 kDa proteins. Marked differences were found between membrane proteins extracted from donor samples in comparison to patient samples. Identification of these proteins was done using the SwissProt database and a literature search. Mostly non-genomic progesterone receptors were identified; others included oestrogen receptor, a phosphotyrosyl protein, P34H, equatorial segment protein, mannose lectin receptor, human guanylylcyclase receptor, epididymal protease inhibitor receptor, PH30 and estradiol binding protein. The function of the membrane surface proteins identified in this study plays a vital role in fertilization. A few of these functions include sperm attachment and binding to the oocyte as well as penetration thereof. Others play a role in signalling events such as capacitation, hyperactivation and acrosome reaction. The absence of these proteins in patient sperm possibly accounts for the functional inability to successfully achieve fertilization suggesting that this provides molecular insight to reasons for infertility amongst men. In addition to this, proteins presented by patient samples that were absent in healthy donors may too account for their infertility status. Estradiol binding protein and PH30 are two proteins presented only in patient samples. Their function plays a role in the inhibition of the acrosome reaction and sperm-egg fusion, respectively. In conclusion, these differences in protein expression between fertile donors and patients may form the molecular basis of infertility amongst men and indicates possibilities for novel proteonomic approaches to improve andrological diagnosis in future.
3

Separation Of Chromate And Borate Anions By Polymer Enhanced Ultrafiltration From Aqueous Solutions Employing Specifically Tailored Polymers

Oktar Doganay, Ceren 01 December 2007 (has links) (PDF)
In this study two polychelatogens for borate and a polyelectrolyte for chromate retention (R) were designed for investigating the effect of pH and loading (g metal /g polymer) on the separation performances of the synthesized polymers using continuous polymer enhanced ultrafiltration. Increase in pH increased the retention of borate for all of the synthesized polymers. Decrease in the loading resulted in an enhancement in boron retention with PNSM and PNSL. When COP was utilized, retentions remained almost constant after a certain loading, probably due to possible adverse effects of high polymer concentrations on polymer conformation in aqueous solutions. Decrease in loading caused an increase in the retention of chromate until a loading of 0.01. After that a slight decrease was observed. Maximum Cr (VI) retention was obtained as 0.70 for a loading of 0.01 and a pH of 4. Effect of crowding on Cr(VI) retention was also investigated. It was observed that retention does not only depend on the loading but also on the concentrations of both Cr (VI) and PDAM. Effect of the presence of competing anions such as chloride and sulfate on the retention of chromate was investigated to see the effect of competing anion charge to the selectivity of the synthesized polyelectrolyte. Addition of both anions decreased the retention of Cr(VI) . Divalent sulfate decreased the retention more than monovalent chloride indicating that charge of the anion may be the predominant variable in the retention of chromate using PDAM. Finally, dynamic and static light scattering measurements were performed to investigate the conformational changes in the structure of the synthesized polymers at different pH values as well as in the presence of boron in the solution. In this study, it is shown that PEUF can be successfully applied to for boron and Cr (VI) retention with the synthesized polymers. Satisfactory retention values were obtained both for boron and Cr (VI). Even if the retention of Cr (VI) decreased with the addition of high amount of competing anions, significant Cr (VI) retentions could be obtained.
4

Decomposition of Aromatic Amines in a Jet Fuel Surrogate

Rohaly, Matthew Joseph January 2014 (has links)
No description available.
5

Sistema automatizado para a medição de desvios de forma e orientação / Automated system for measuring form and orientation deviations

Sagawa, Juliana Keiko 12 September 2008 (has links)
O modo de produção vigente exige cada vez mais rapidez, precisão e eficiência nos processos. Em resposta a essas tendências, constituem-se desafios à área de Metrologia a obtenção de sistemas de medição e algoritmos de avaliação de erros mais precisos; a avaliação de incertezas com precisão; e a execução de medições com rapidez. Neste trabalho apresenta-se um Sistema Automatizado de medição para avaliação dos desvios de forma e orientação de componentes. O sistema é baseado na utilização de um robô industrial com seis graus de liberdade e sensores de deslocamento do tipo LVDT. O emprego de sistemas como o proposto para a avaliação de desvios geométricos está condicionado à utilização de um modelo matemático de separação de erros, uma vez que a acurácia de posicionamento e a repetibilidade dos robôs disponíveis atualmente não são adequadas à medição de grandezas micrométricas. Além da aplicação do modelo de separação de erros, este trabalho inclui a elaboração modelos e rotinas de processamento de dados para a avaliação de desvios geométricos. Sistemas similares desenvolvidos foram aplicados principalmente à medição de desvios de retilineidade, e em alguns casos, circularidade. Neste trabalho, buscou-se ampliar o escopo de aplicações deste tipo de sistema, de forma a abranger não só a avaliação dos desvios de retilineidade, mas também a avaliação dos desvios de planicidade e perpendicularismo. Além disso, o enfoque da pesquisa foi dirigido à avaliação do desempenho do sistema e do modelo de separação de erros, por meio da realização de testes experimentais com três peças distintas e por meio de análise comparativa com sistemas convencionais de medição. Os resultados obtidos comprovaram a eficiência do sistema proposto, que destacou-se também por apresentar boa repetibilidade. / The current production system demands fast, efficient and precise processes. In order to address these issues, most of the research efforts in the Metrology area have been focused into the development of faster and more accurate measuring systems as well as into the definition of methods to better evaluate uncertainties in measurement. This work presents an automated system for the evaluation of form and orientation deviations of mechanical components. A six-degree-of-freedom industrial robot and LVDT sensors are used to take the measurements. The implementation of the proposed system depends on the application of a mathematical model for error separation since the accuracy of positioning and repeatability presented by the currently available industrial robots are not suitable for measuring micrometric deviations. Besides the application of the error separation model, this work also includes the development of data processing algorithms for the evaluation of geometrical deviations. Few similar systems to the proposed one were developed and applied mainly for straightness and, in some cases, roundness measurements. This work aimed at broadening the range of applications of this kind of measuring systems, making them suitable for the evaluation of flatness and orthogonality deviations. Additionally, the focus of the research was set to the performance evaluation of the system and the error separation model. In order to do that, experimental tests with three different parts were carried out. The values found were compared to the values of the deviations measured with conventional GD&T practice. The obtained results showed the efficiency of the proposed system, which also presented good repeatability.
6

Effect Of Ionic Strength On The Performance Of Polymer Enhanced Ultrafiltration In Heavy Metal Removal From Aqueous Solutions

Islamoglu, Sezin 01 November 2006 (has links) (PDF)
Effect of ionic strength on the efficiency of heavy metal removal and recovery from aqueous solutions via continuous mode polymer enhanced ultrafiltration (PEUF) method was examined. Application of PEUF to divalent ions of cadmium, nickel and zinc after their prior linking with polyethylenimine (PEI) results in complete removal of metal ions from single component aqueous solutions at high pHs. Binding ability and hence the extent of metal retention in high ionic strength medium exhibits differences between solutions containing single and multicomponent metal mixtures. In single component metal solutions, extent of retention decreases but binding order of metals remains unaffected both in low and high ionic strength medium. But, in binary component metal mixtures, with increase in ionic strength the binding order of metals changes. Fractional separation of Cd, Ni and Zn ions from equimolar binary and ternary mixtures of these metals and effect of ionic strength on fractional separation efficiency were investigated. Depending on pH and salt concentration and metal pairs present in the solution fractional separation can be achieved.Dynamic and static light scattering experiments were performed in order to gain insight about the conformational changes in PEI structure due to the pH and ionic strength alternations in solution. It was found that, the increase in ionic strength reduces the size of the macromolecules. A chemical equilibrium model was developed in order to estimate the apparent binding constants of metal-PEI complexes. Based on the data obtained from continuous and batch mode PEUF experiments apparent binding constants were estimated and compared to reveal the performance differences between these operational modes.
7

Sistema automatizado para a medição de desvios de forma e orientação / Automated system for measuring form and orientation deviations

Juliana Keiko Sagawa 12 September 2008 (has links)
O modo de produção vigente exige cada vez mais rapidez, precisão e eficiência nos processos. Em resposta a essas tendências, constituem-se desafios à área de Metrologia a obtenção de sistemas de medição e algoritmos de avaliação de erros mais precisos; a avaliação de incertezas com precisão; e a execução de medições com rapidez. Neste trabalho apresenta-se um Sistema Automatizado de medição para avaliação dos desvios de forma e orientação de componentes. O sistema é baseado na utilização de um robô industrial com seis graus de liberdade e sensores de deslocamento do tipo LVDT. O emprego de sistemas como o proposto para a avaliação de desvios geométricos está condicionado à utilização de um modelo matemático de separação de erros, uma vez que a acurácia de posicionamento e a repetibilidade dos robôs disponíveis atualmente não são adequadas à medição de grandezas micrométricas. Além da aplicação do modelo de separação de erros, este trabalho inclui a elaboração modelos e rotinas de processamento de dados para a avaliação de desvios geométricos. Sistemas similares desenvolvidos foram aplicados principalmente à medição de desvios de retilineidade, e em alguns casos, circularidade. Neste trabalho, buscou-se ampliar o escopo de aplicações deste tipo de sistema, de forma a abranger não só a avaliação dos desvios de retilineidade, mas também a avaliação dos desvios de planicidade e perpendicularismo. Além disso, o enfoque da pesquisa foi dirigido à avaliação do desempenho do sistema e do modelo de separação de erros, por meio da realização de testes experimentais com três peças distintas e por meio de análise comparativa com sistemas convencionais de medição. Os resultados obtidos comprovaram a eficiência do sistema proposto, que destacou-se também por apresentar boa repetibilidade. / The current production system demands fast, efficient and precise processes. In order to address these issues, most of the research efforts in the Metrology area have been focused into the development of faster and more accurate measuring systems as well as into the definition of methods to better evaluate uncertainties in measurement. This work presents an automated system for the evaluation of form and orientation deviations of mechanical components. A six-degree-of-freedom industrial robot and LVDT sensors are used to take the measurements. The implementation of the proposed system depends on the application of a mathematical model for error separation since the accuracy of positioning and repeatability presented by the currently available industrial robots are not suitable for measuring micrometric deviations. Besides the application of the error separation model, this work also includes the development of data processing algorithms for the evaluation of geometrical deviations. Few similar systems to the proposed one were developed and applied mainly for straightness and, in some cases, roundness measurements. This work aimed at broadening the range of applications of this kind of measuring systems, making them suitable for the evaluation of flatness and orthogonality deviations. Additionally, the focus of the research was set to the performance evaluation of the system and the error separation model. In order to do that, experimental tests with three different parts were carried out. The values found were compared to the values of the deviations measured with conventional GD&T practice. The obtained results showed the efficiency of the proposed system, which also presented good repeatability.
8

Binding of radiographic contrast media to serum proteins : a clinical and experimental investigation of their adverse effects through influence on active steroid hormone levels

Wirell, Staffan January 1982 (has links)
<p>S. 1-40: sammanfattning, s. 41-96: 5 uppsatser</p> / digitalisering@umu.se
9

Métodos multivariados para a elucidação de informações analíticas em amostras complexas

Mendes, Thiago de Oliveira 04 August 2015 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-04T14:27:39Z No. of bitstreams: 1 thiagodeoliveiramendes.pdf: 10542310 bytes, checksum: 9b116b21c7d753e1a26ffeaeab698db5 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T15:58:12Z (GMT) No. of bitstreams: 1 thiagodeoliveiramendes.pdf: 10542310 bytes, checksum: 9b116b21c7d753e1a26ffeaeab698db5 (MD5) / Made available in DSpace on 2016-01-25T15:58:12Z (GMT). No. of bitstreams: 1 thiagodeoliveiramendes.pdf: 10542310 bytes, checksum: 9b116b21c7d753e1a26ffeaeab698db5 (MD5) Previous issue date: 2015-08-04 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O estudo de amostras complexas, como alimentos, fármacos e fluidos biológicos necessita de métodos robustos de análise de dados, uma vez que estas amostras podem conter informações de dezenas a milhares de constituintes. A pesquisa desenvolvida neste trabalho tem como temática principal a aplicação de métodos multivariados de análise para extrair informações a partir dos espectros vibracionais (infravermelho e Raman) ou de massas, de amostras complexas. Técnicas de separação tais como CE, GC e LC são utilizadas como abordagem auxiliar para fornecer informações aos modelos multivariados propostos. Cinco aplicações são discutidas no texto. A primeira faz o uso da PCA sobre cromatogramas de GC de diferentes amostras de óleo de soja e azeite de oliva, buscando realizar uma análise exploratória das duas classes de óleos vegetais. Na sequência são analisadas misturas com adições controladas de óleo de soja em azeite de oliva pelas técnicas de absorção infravermelha e espalhamento Raman, com o objetivo de propor uma regressão PLS que determine o percentual de adição. A segunda aplicação aborda a busca de marcadores vibracionais, infravermelho e Raman, que possam ser utilizados para a quantificação do percentual de gordura em amostras de leite fluido. Neste estudo foi realizada uma análise do perfil de ácidos graxos presentes no leite pela técnica de GC, com o objetivo de selecionar uma molécula representativa de triacilglicerol que foi utilizada para simular espectros vibracionais por modelos teóricos. A partir dos espectros obtidos por simulação computacional foi proposta a atribuição de modos vibracionais presentes na gordura do leite. Foi também proposto um modelo MLR preditor do percentual de gordura em amostras de leite fluido, cujas variáveis vibracionais foram previamente selecionadas a partir de um modelo PLS. Outra aplicação foi a utilização de modelo PLS sobre espectros Raman para a determinação simultânea das concentrações de rifampicina, isoniazida, etambutol e pirazinamida em amostras de comprimidos utilizados no tratamento antituberculose. A quarta aplicação está focada na quantificação do percentual de soro de leite adicionado fraudulentamente em amostras de leite por análise do perfil de ácidos graxos por GC e CE. Uma análise discriminante foi utilizada para selecionar marcadores de ácidos graxos que foram monitorados por regressão MLR. Por fim, é apresentada a elaboração de um tutorial completo de análise univariada e multivariada de dados, desenvolvido em R-software, para a determinação de biomarcadores em experimentos de metabolômica baseados em análises de espectros de massas. Todas estas aplicações têm como interseção o uso de métodos multivariados de análise de dados como ferramenta principal para propor novos marcadores vibracionais/metabolitos, assim como, métodos alternativos para a quantificação de diferentes analitos. / The study of complex samples such as food, drugs, and biological fluids require a robust data analysis methods, since these samples may contain information tens of thousands of constituents. The research developed in this work has as main theme the application of multivariate analysis methods to extract information from the vibrational spectra (infrared and Raman) or mass spectra of complex samples. Separation techniques such as CE, GC and LC are used as an auxiliary approach to providing information to the proposed multivariate models. Five applications are discussed in the text. The first makes use of PCA on GC chromatograms of samples of soybean oil and olive oil, searching for an exploratory analysis of the two classes of vegetable oils. Following are analyzed with mixtures of controlled additions of soybean oil in olive oil, by infrared absorption and Raman scattering techniques, with the aim of proposing a PLS regression to determine the percentage of addition. A second application addresses the search vibrational markers, infrared and Raman, that may be used to quantify the percentage of fat in milk fluid samples. In this study we carried out a profile analysis of fatty acids present in milk by CG technique, for the purpose of selecting a representative molecule of triacylglycerol was used to simulate vibrational spectra by theoretical models. From the spectra obtained by computer simulation was proposed assignment of vibrational modes present in milk fat. It was also proposed an MLR predictor model of the percentage of fat in fluid samples, whose vibrational variables were previously selected from a PLS model. Another application has been the use of PLS model of Raman spectra for the simultaneous determination of concentrations of rifampicin, isoniazid, ethambutol and pyrazinamide in tablet samples used in anti-tuberculosis treatment. The fourth application is focused on quantifying the percentage of whey added fraudulently in milk samples for analysis of the fatty acid profile by GC and CE. A discriminant analysis was used to select fatty acids markers that were monitored by MLR regression. Finally, it shows the preparation of a complete tutorial of univariate and multivariate data analysis, developed in R-software, for the determination of biomarkers in metabolomics experiments based on mass spectra analysis. All these applications have the intersection as the use of multivariate methods of analyzing data as the main tool to propose new vibrational / metabolite markers as well as alternative methods for quantification of various analytes.
10

Stanovení vybraných "Musk" sloučenin v biotických vzorcích / Determination of selected musk compounds in biotic samples

Blahová, Eliška January 2008 (has links)
Musk compounds (MUSK) or synthetic fragrances are organic substances commonly used as fragrant constituents of detergents, soaps, cosmetics, personal care products, industrial and in-house cleaning agents, industrial plasticizers, chewing tobacco and fresheners. The big attention is pushed ahead studying these compounds, their fate in different parts of ecosystems and studying their characteristics at present, because musks infiltrate many environmental components, particularly aquatic and marine ecosystems, through their large application and their ability to be perzistant. This diploma thesis was focused on four synthetic “classical” fragrances used over the world. The aim of this study was to perform a method optimisation for the determination of selected fragrances in biotic matrix. There was made an evalution of ability of selected water treatment plant to clear away musks from water, these results were used for evaluating contamination measurement of aquatic ecosystem. The identification and quantification of analytes was carried out by high resolution gas chromatography - mass spectrometry (HRGC/MS).

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