Dissertations / Theses on the topic 'Attenuation factor'

Orientador: Marcelo Brocchi
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: O gênero Salmonella spp é formado por bacilos gram-negativos, que podem ser divididos em 3 espécies: S. enterica, S. bongori e S. subterranea. A maioria das sorovariedades patogênicas para o homem está incluída no subgrupo I da espécie S. enterica. A infecção por S. enterica inicia-se com a ingestão de água ou alimentos contaminados. Estes microrganismos são patógenos intracelulares facultativos e, uma vez ingeridos, apresentam a capacidade de aderir e invadir células da mucosa intestinal, preferencialmente células M. Uma vez ultrapassada a mucosa intestinal, S. enterica invade, persiste e prolifera no interior de vacúolos de células do sistema retículo endotelial podendo assim, alcançar diferentes órgãos e tecidos do hospedeiro, causando infecção sistêmica. Sendo assim, linhagens mutantes avirulentas, mas ainda capazes de causar infecção transitória, são boas candidatas a potenciais vacinas vivas orais. Tais mutantes são potenciais carreadores de proteínas heterólogas, compondo, assim, as chamadas vacinas multi-valentes. Que seja de nosso conhecimento, não existem mutantes atenuados de S. enterica desenvolvidos inteiramente no Brasil, havendo necessidade de pagamento de patentes a grupos estrangeiros para sua utilização. Em eucariotos, o DNA cromossômico bacteriano está associado a proteínas (histonas) formando o núcleo, enquanto em procariotos, estas proteínas são denominadas histona-like, formando um nucleóide. Dentre essas proteínas podemos citar a IHF (integration host factor), um heterodímero que controla ou influencia vários processos celulares, como a duplicação e recombinação do DNA, além de regular positiva ou negativamente a expressão de vários genes. Neste estudo, mutantes nulos para os genes himA e himD de IHF foram criados pela técnica de recombinação homóloga mediada pelo sistema ? Red (Datsenko e Wanner, 2000) e testados quanto a atenuação da virulência e capacidade de desencadear resposta imune efetiva e protetora contra a salmonelose murina. Os mutantes também foram caracterizados quanto a diversas características biológicas, como a capacidade de invasão e sobrevivência intracelular, resistência a radicais reativos de oxigênio e nitrogênio, ente outras, sendo os resultados comparados com as respectivas linhagens selvagens. Os mutantes himA e himD de S. enterica foram atenuados e capazes de induzir resposta imune protetora quando desafiados com doses elevadas da linhagem selvagem, indicando que estas linhagens recombinantes são potenciais candidatas a vacinais vivas orais
Abstract: The genus Salmonella sp is formed by gram-negative bacilli, which can be divided into 3 species: S. enterica, S. bongori and S. subterranea. The majority of the serovars pathogenic to humans is included in the subgroup I of the S. enterica species. The infection with S. enterica starts either the ingestion of contaminated water or food. These microorganisms are facultative intracellular pathogens and, once ingested, they have the capacity to adhere and invade cells of the intestinal mucosa, with preference for M cells. Then, S. enterica can invade and proliferate within vacuoles of immune cells, particularly macrophages, achieving different organs and tissues of the host, causing systemic infection. Mutant strains of S. enterica with attenuation of the virulence but that are still able to cause a transient infection, are good candidates for potential live oral vaccines. These mutants are also good carriers of heterologous antigens to cells of the immunological system, been able to induce an effective immunological response. To the best of our knowledge, no mutants of this type were developed in Brazil leading to the needed to pay royalties to foreign groups for their use. In prokaryotes the genomic DNA are associated with a number of proteins, the so called histone-like proteins, with structural and regulatory properties, forming the nucleoid. The IHF (Integration Host Factor) is one of the more abundant histone-like in prokaryotes. IHF is a heterodimeric DNA-binding protein that controls a number of cellular processes, such as DNA duplication and DNA recombination and also modulates the expression of different genes. In this work we constructed recombinant strains of S. enterica mutants for the himA and himD genes that encode for the IHF subunits using the ? Red system (Datsenko and Wanner, 2000) and tested for attenuation and immunogenicity. The mutant strains were also characterized and compared to the parental strains for other biological characteristics such as the capacity to invade and proliferate into eukaryotic cells and to survive to different stress conditions. The S. enterica himA and himD mutant strains were attenuated for virulence and able to induce a protective immunity against the wild type strain of S. enterica indicating that these recombinant strains are candidates to formulate a new live oral vaccine
Mestrado
Ciencias Basicas
Mestre em Clinica Medica

This thesis deals with the problem of shielding ionizing radiation which is a beam that has enough energy to ionize an atom or a molecule of an irradiated substance. This radiation can occur in nuclear facilities such as a nuclear power plant, a particle accelerator, or in X-rays in healthcare. Until now, standard shielding materials, most often lead or concrete, have been used to protect against ionizing radiation. New trends are therefore trying to replace these materials with lighter, more effective and harmless materials. The practical part is focused on measure the data to obtain the basic properties of shielding materials, such as the attenuation factor and the buildup factor. A measuring platform is described here, which can be used to measure the data needed to calculate the attenuation factor and the buildup factor. The measurement results are compared with tabular values to determine the accuracy of the measurements. Furthermore, the results of measurements of five concrete materials from the company MICo, spol. s r.o. To obtain theoretical values, the simulation program MCNP6 was used, in which it is possible to create a model of the measuring platform, which was used in practical measurements. Next the shielding material, source and detector are defined. The result lead again to the data needed to determine the attenuation factor. The results of measurement and simulation data in MCNP6 are evaluated and graphically processed into such a form that it is possible to compare the properties of shielding materials with each other.

Mesure des coefficients d'attenuation des elements de numero atomique 46 a 54 dans le domaine 15 a 45 kev. Determination des parametres de la loi de variation empirique du coefficient d'attenuation en fonction de la longueur d'onde du rayonnement. Determination des facteurs de diffusion anomale vers l'avant, en utilisant la relation de dispersion

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Seismic wave dispersion and attenuation studies have become an important tool for lithology and fluid discrimination in hydrocarbon reservoirs. The processes associated to attenuation are complex and are encapsulated in a single quantitative description called quality factor (Q). The present dissertation has the objective of comparing different approaches of Q determination and is divided in two parts. Firstly, we made performance and robustness tests of three different approaches for Q determination in the frequency domain. They are: peak shift, centroid shift and spectral ratio. All these tests were performed in a three-layered model. In the suite of tests performed here, we varied the thickness, Q and inclination of the layers for propagation pulses with central frequency of 30, 40 and 60 Hz. We found that the centroid shift method is produces robust results for the entire su?te of tests. Secondly, we inverted for Q values using the peak and centroid shift methods using an sequential grid search algorithm. In this case, centroid shift method also produced more robust results than the peak shift method, despite being of slower convergence
Os estudos da dispers?o e da atenua??o das ondas s?smicas t?m se tornado uma ferramenta importante na discrimina??o das litologias e conte?do de fluidos em reservat?rios de hidrocarbonetos. Os processos associados ? atenua??o s?o complexos e sintetizados em uma ?nica descri??o quantitativa chamada fator de qualidade (Q). A presente disserta??o tem o objetivo de comparar diferentes aproxima??es para a determina??o de Q e ? dividido em duas partes. Primeiramente, fizemos um teste de performance e robustez de tr?s m?todos diferentes para a determina??o de Q no dom?nio da freq??ncia. S?o elas: deslocamento de pico, deslocamento de centr?ide e raz?o espectral. Todos os testes foram feitos em um modelo de tr?s camadas. O conjunto de testes aqui realizados consistia em variar a espessura da camada, Q e a inclina??o das camadas para a propaga??o dos pulsos com freq??ncias centrais de 30, 40 e 60 Hz. Pudemos determinar que o m?todo do deslocamento de centr?ide produz os resultados mais robustos para todo o conjunto de testes. Em segundo lugar, invertemos os valores de Q utilizando os m?todos de deslocamento de pico e de centr?ide utilizando um algoritmo de busca seq?encial. Neste caso, o m?todo de centr?ide tamb?m produziu os resultados mais robustos que o m?todo de deslocamento de picos, apesar de ter uma converg?ncia mais lenta

The aim of this thesis is to present a simple model for the radiation to light conversion processes in fluorescent layers as an aid in future developments and applications. Optimisation between sensitivity and spatial resolution for fluorescent layers in digital radiology is a delicate task where the extrinsic efficiency for various phosphors needs to be established for varying parameters. The extrinsic efficiency of a fluorescent layer can be expressed as the ratio of the light energy per unit area at the screen surface to the incident xray energy fluence. Particle size is a critical factor in determining the value of the extrinsic efficiency, but in most models it is not treated as an independent variable. Based on the definition of a light extinction factor (ξ), a model is proposed such that, knowing the intrinsic efficiency η, the particle size and the thickness of a certain make of screen, the extrinsic efficiency can be calculated for an extended range of particle sizes and / or screen thicknesses. The light extinction factor ξ is an optical parameter determined from experimental data on extrinsic efficiency. The proposed model is compared to established methods. Further experiments have confirmed the validity of the model. Monte-Carlo simulations have been utilised to refine the calculations of energy imparted to the phosphor by taking into account the escape of scattered and K-radiation generated in the screen and interface effects at the surfaces. The luminance was measured for a set of in-house manufactured screens of varying thicknesses and particle sizes. Utilising the proposed model, the corresponding calculated values deviated ± 14 %.within the studied range.

Orientador: Marcelo Brocchi
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O gênero Salmonella pertence à família Enterobacteriaceae que agrupa bacilos Gram-negativos, anaeróbios facultativos, fermentadores e geralmente flagelados. S. enterica é um dos patógenos de origem alimentar mais prevalente, sendo que infecções causadas por essa bactéria podem estar relacionadas a praticamente todos os tipos de alimentos. O trabalho foi proposto com o intuito de realizar a caracterização fenotípica e molecular de linhagens atenuadas de Salmonella enterica Typhimurium para genes codificadores de proteínas associadas ao nucleóide (NAPs Nucleoid associated Proteins). As características fenótipicas dos mutantes nulos de Salmonella enterica para os genes ihfA ou ihfB, codificadores das subunidades A e B de IHF, foram avaliadas através de crescimento in vitro, motilidade, sobrevivência frente ao estresse nutricional (sobrevivência em fase estacionária), sob condições ácidas, na presença de sais biliares e quanto à capacidade de invasão e sobrevivência em macrófagos (linhagem J774A.1). Testes de confirmação da atenuação e avaliação da capacidade de induzir proteção em caso de infecção por S. enterica foram realizados utilizando o modelo murino. Os mutantes não apresentaram diferença no crescimento in vitro e na capacidade de sobreviver na presença de sais biliares em comparação com a linhagem selvagem. As linhagens mutantes para os genes ihfA ou ihf ihf ihfB) apresentaram uma menor capacidade de sobrevivência sob condições ácidas quando comparadas com a linhagem selvagem. A motilidade dos mutantes simples também foi reduzida. Os mutantes simples e duplo apresentaram maior capacidade de sobreviver sob estresse nutricional quando comparados com a linhagem selvagem. O mutante para o gene ihfA e o duplo mutante apresentaram um aumento na capacidade de invadir macrófagos. ihf ihfB mostraram uma capacidade aumentada em sobreviver no interior de macrófagos quando comparadas com a linhagem selvagem. Os mutantes nulos viii de Salmonella enterica para os genes ihfA ou ihfB apresentam atenuação, em diferentes graus, quanto à virulência e apresentaram capacidade de induzir proteção no modelo murino de infecção por S. enterica. Esses resultados demonstram que essa proteína apresenta função relacionada com a virulência bacteriana, sendo um importante alvo de estudo na busca de linhagens atenuadas
Abstract: The genus Salmonella belongs to the Enterobacteriaceae family that comprises Gram-negative bacillus, facultative anaerobe, fermenting and generally flagellate. S. enterica is one of the most prevalent food-borne pathogen, and infections caused by this bacterium can be associated to almost all types of food. The work was proposed with the purpose of performing phenotypic and molecular characterization of attenuated strains of Salmonella enterica Typhimurium for genes encoding proteins associated with the nucleoid (NAPs - Nucleoid associated Proteins). The phenotypic characteristics of the null mutants of Salmonella enterica for genes ihfA or ihfB, encoding the A and B subunits of IHF, were evaluated by in vitro growth, motility, survival under nutritional stress (survival in the stationary phase), under acidic conditions, in the presence of bile salts and for the ability of invasion and survival in macrophages (J774A.1 strain). Attenuation tests and evaluation of the capacity to induce protection in case of infection by S. enterica were performed using the murine model. The mutants showed no difference in the in vitro growth and the ability to survive in the presence of bile salts in comparison with the wild type strain. The single mutant for ihfA or ihf ihf ihfB) showed decreased survival under acidic conditions when compared to the wild type strain. Motility of single mutants was also reduced. Single and double mutants showed higher ability to survive under nutritional stress when compared with the wild type strain. The mutant gene for ihfA and the double mutant showed an increased ability to invade ihf ihfB mutants showed an increased ability to survive within macrophages when compared with the wild type strain. Null mutants of Salmonella enterica for ihfA or ihfB genes exhibited attenuation, to varying degrees, for virulence and showed ability to induce protection in a murine model of infection by S. enterica. x These results demonstrate that this protein has function associated to bacterial virulence and is an important subject of study in search for attenuated strains
Mestrado
Genetica de Microorganismos
Mestra em Genética e Biologia Molecular

This thesis addresses the problem of predicting satellite path rain fade duration statistics for an arbitrary location, frequency, elevation angle and polarization. It summarizes the development of a dynamic stochastic model. From this model a technique is derived for predicting fade duration statistics for one site using measured attenuation data at another site. This technique is evaluated by comparing predicted and experimental results for several locations, frequencies, elevation angles and polarizations.
M.S.

The phenomenon of plume persistence was observed for five federal Superfund sites by analysis of historical groundwater-withdrawal and contaminant-concentration data collected from long-term pump-and-treat operations. The potential factors contributing to plume persistence are generally recognized to include incomplete isolation of the source zone, permeability heterogeneity, well-field hydraulics, and non-ideal (rate-limited, nonlinear) desorption. However, the significance of each factor, especially the site-specific contribution is undetermined, which is very important for site development and management. One objective of this study is to quantify the impacts of different factors on mass-removal efficiency. Three-dimensional (3D) numerical models were used to simulate the impact of different well-field configurations on pump-and-treat mass removal. The relationship between reduction in contaminant mass discharge (CMDR) and mass removal (MR) was used as the metric to examine remediation efficiency. Results indicate that (1) even with effort to control the source, residual impact of source can still be a factor causing plume persistence, (2) the well-field configuration has a measurable impact on mass-removal efficiency, which can be muted by the influence of permeability heterogeneity, (3) in terms of permeability heterogeneity, both variance and correlation scale influence the overall mass-removal behavior, (4) the CMDR-MR relationship can be used to quantify the impacts of different factors on mass-removal efficiency at the plume scale. It has been recognized that the use of pump and treat for groundwater remediation will require many decades to attain site closure at most complex sites. Thus, monitored natural attenuation (MNA) and enhanced attenuation (EA) have been widely accepted as alternatives because of their lower cost and sustainable management for large, complex plumes. However, the planning and evaluation of MNA/EA applications require greater levels of characterization data than typically collected. Advanced, innovative methods are required to characterize specific attenuation processes and associated rates to evaluate the feasibility of MNA/EA. Contaminant elution and tracer (CET) tests have been proposed as one such advanced method. Another objective of this study is to investigate the use of modified well-field configurations to enhance the performance of CET tests to collect critical site-specific data that can be used to better delineate attenuation processes and quantify the associated rate coefficients. Three-dimensional numerical models were used to simulate the CET test with specific well-field configurations under different conditions. The results show that the CET test with a nested (two-couplet) well-field configuration can be used to characterize transport and attenuation processes by eliminating the impact of the surrounding plume. The results also show that applying select analytical mass-removal functions can be an efficient method for parameter estimation, as it does not require the use of mathematical transport modeling and does not require the attendant input data that are costly and time-consuming to obtain.

Thesis (Ph. D.)--Florida State University, 2007.
Advisor: Katinka Dijkstra, Florida State University, College of Arts and Sciences, Dept. of Psychology. Title and description from dissertation home page (viewed Oct. 2, 2007). Document formatted into pages; contains viii, 65 pages. Includes bibliographical references.

Gonadotrophin surge attenuating factor (GnSAF) is a non-steroidal ovarian factor which reduces pituitary responsiveness to GnRH both in vitro and in vivo. GnSAF is present in serum from superovulated women in a 141 kDa molecular weight form. GnSAF bioactivity (suppression of GnRH-induced LH secretion from cultured rat pituitary cells) in serum from superovulated women is not overcome by incubation with an inhibin antibody, demonstrating that it is distinct from inhibin. Under the culture conditions used, the ovarian steroids had no significant suppressive effects on GnRH-induced LH secretion, showing that GnSAF bioactivity is not due oestradiol or progesterone. GnSAF is also present in serum from the follicular phase of spontaneously cycling women with maximal levels being produced during the mid follicular phase. It has been suggested that GnSAF production during the follicular phase suppresses LH release from the pituitary until the levels of oestradiol produced by the developing follicle are high enough to overcome the effects of GnSAF and the LH surge occurs. However, suppression of LH secretion by an enriched GnSAF preparation is potentiated by oestradiol and progesterone, both individually and in combination. This suggests that it is not a rise in steroid positive feedback but a decrease in GnSAF negative feedback which enables the LH surge to occur. Follistatin and GnSAF in combination have additive effects on the suppression of GnRH-induced LH secretion, whereas GnSAF and inhibin in combination cause no greater suppression than they do individually. GnSAF present in inhibin-stripped human follicular fluid is also able to reduce both the GnRH self-priming response, and its augmentation by progesterone, by rat pituitary cells in culture after only 90 minutes exposure. Inhibin and follistatin have no such effects under the same conditions.

Дисертаційна робота присвячена рішенню актуальної науково-прикладної задачі, яка полягає в розробці методу визначення рівнів основних та побічних електромагнітних випромінювань в урбанізованих середовищах за рахунок удосконалення моделей їх розповсюдження. Обґрунтовано необхідність в підвищені ефективності використання пристроїв моніторингу електромагнітної обстановки на основі аналізу особливостей розповсюдження електромагнітних випромінювань в урбанізованому середовищі та недоліків існуючого математичного апарату для їх опису. Запропоновано структуру експериментальної установки та проведено дослідження особливостей розповсюдження основних та побічних електромагнітних випромінювань в урбанізованому середовищі, зроблено прогнозування характеру їх розповсюдження на прикладі моделі COST231MWM. Представлено модель оцінки енергетичних характеристик сигналів в точці спостереження на основі експериментальних досліджень затухання електромагнітних випромінювань в залежності від частоти, характеру перешкоди та відстані в реальних умовах експлуатації та отримано відповідні графічні й математичні залежності, що лягли в основу методу удосконалення моделей розповсюдження електромагнітних випромінювань. Обґрунтовано наукові методи синтезу деталізованої структурної схеми процесів виявлення та локалізації неконтрольованих та неліцензованих пристроїв передавання інформації по радіоканалах, що включають розробку програмного забезпечення для визначення зони електромагнітної доступності всередині приміщення. Розроблено оригінальний підхід, алгоритм функціонування та методи синтезу засобів пошуку в умовах радіоперешкод та виявлення джерел електромагнітних випромінювань.
Диссертация посвящена решению актуальной научно-прикладной задачи, которая заключается в разработке метода определения уровней основных и побочных электромагнитных излучений в урбанизированных средах за счет совершенствования моделей их распространения. Обоснована необходимость в повышении эффективности использования устройств мониторинга электромагнитной обстановки на основе анализа особенностей распространения электромагнитных излучений в урбанизированной среде и недостатков существующего математического аппарата для их описания. Предложена структура экспериментальной установки и проведены исследования особенностей распространения основных и побочных электромагнитных излучений в урбанизированной среде, сделано прогнозирования характера их распространения на примере модели COST 231 MWM. Представлена модель оценки энергетических характеристик сигналов в точке наблюдения на основе экспериментальных исследований затухания электромагнитных излучений в зависимости от частоты, характера препятствия и расстояния в реальных условиях эксплуатации и получены соответствующие графические и математические зависимости, которые легли в основу метода совершенствования моделей распространения электромагнитных излучений. Обоснованнонаучныеметоды синтеза детализированной структурной схемы процессов обнаружения и локализации неконтролируемых и нелицензированных устройств передачи информации по радиоканалам, включающих разработку программного обеспечения для определения зоны электромагнитной доступности внутри помещения. Разработан оригинальный подход, алгоритм функционирования и методы синтеза средств поиска в условиях радиопомех и обнаружения источников электромагнитных излучений.
The dissertation is devoted to the decision of the actual scientific and applied problem which consists in the development of a method of definition of levels of the basic and secondary electromagnetic radiations in the urban environments at the expense of perfection of models of their distribution. The necessity in the increased efficiency of use of devices of monitoring of an electromagnetic situation on the basis of the analysis of features of distribution of electromagnetic radiations in the urban environment and lacks of the existing mathematical device for their description is proved. The structure of the experimental setup is proposed and the peculiarities of propagation of main and secondary electromagnetic radiations in the urban environment are studied, the nature of their propagation is predicted on the example of COST231Milti-Wall-Model. The nature of the interference and the distance in real operating conditions and the corresponding graphical and mathematical dependences were obtained, which formed the basis of the method of improving the models of electromagnetic radiation propagation. Scientific methods of synthesis of the detailed structural scheme of processes of detection and localization of uncontrolled and unlicensed devices of information transmission on radio channels, including development of the software for definition of a zone of electromagnetic accessibility indoors are substantiated. An original approach, algorithm of functioning and methods of synthesis of search means in the conditions of radio interference and detection of sources of electromagnetic radiation are developed. To solve the problem in the dissertation the following tasks have been set and solved: – the necessity in the increased efficiency of use of devices of monitoring of an electromagnetic situation on the basis of the analysis of features of distribution of electromagnetic radiations in the urban environment and lacks of the existing mathematical approach for their description is proved. – has been created the model for estimating the energy characteristics of signals at the observation point based on experimental studies of electromagnetic radiation attenuation depending on the frequency, nature of interference and distance in real operating conditions, for obtaining graphical and mathematical dependences. Has been developed method for improving radio wave propagation models (on the example of the COST 231 MWM). – development of a method for detection and localization of uncontrolled and unlicensed devices for transmitting information on the radio channel in a complex interfering and electromagnetic environment inside a dedicated room of the electromagnetic availability zone and development of a detailed structure of this process. – development of software that will determine the perimeter of the electromagnetic availability zone on the basis of the obtained mathematical apparatus for the purposes of monitoring the electromagnetic environment indoors and information security. – conducting experimental verification of the obtained results to assess the peculiarities of the propagation of main and secondary electromagnetic radiation in the urban environment, predicting the nature of their distribution in applied models of COST 231 MWM, based on the results, evaluated by viewing and creating semantic information about side electromagnetic radiation and pickup.

Factors influencing natural attenuation of dinitrotoluenes (DNT) in surface soils and the application of monitored natural attenuation (MNA) as a remediation strategy were examined using contaminated soils from Badger Army Ammunition Plant (BAAP). Based on the previous research involving contaminated media obtained from locations at BAAP, and the fact that groundwater at the site is not contaminated, it seemed likely that aerobic biodegradation of DNT is active without intervention, and that natural attenuation may be an effective strategy for managing the contamination that exists at BAAP. Microcosms showed that microbes indigenous to soils are capable of 2,4-DNT mineralization and that DNT will adsorb reversibly and become bioavailable. In column studies 2,4-DNT biodegradation was observed and the nitrite evolved during DNT degradation was presumably removed due to oxidation by nitrite oxidizers. The use of simulated rainwater as influent with no nutrient amendments suggests that nutrients do not limit the biodegradation of low concentrations of DNT in the soil tested. In the chemostat study carried out to study effect lowering of temperature (22㬠15㬠10㬠7.5㠡nd 4㩠on biodegradation of DNT at hydraulic retention time of 2.5 days, no sustained change in the DNT substrate removal was observed with change in temperature, but it had a large effect on the nitrite oxidizers. This suggests that the seasonal fluctuations in temperature will have minimal effect on the DNT removal via biodegradation at temperatures above 0㮠Nitrite oxidizers were active at 22㬠their activity decreased at 15㠡nd ceased at temperatures 10㠡nd lower. Nitrite is generally taken as a line of evidence for biodegradation of DNT. The results from the soil column study and chemostat showed that nitrite measurement should not be always taken as a conclusive indicator of DNT degradation. It should be taken into consideration that absence of nitrite does not necessarily mean absence of DNT biodegradation (probably at high temperatures).

INTRODUCCIÓN: La atención primaria de salud es el escenario ideal para la identificación precoz de pacientes con enfermedad de hígado graso no alcohólico (EHGNA). La EHGNA es una enfermedad potencialmente progresiva que puede conducir a la cirrosis y cáncer de hígado, pero con frecuencia no se reconoce y los sujetos en riesgo de sufrirla, no suelen ser evaluado. El parámetro de atenuación controlada (CAP) es un método fiable para cuantificar de forma no invasiva la presencia de grasa en el hígado. Tiene la ventaja de que también realiza de forma simultánea la medición de la rigidez hepática (LS), que nos da una estimación de la presencia de fibrosis hepática significativa. Actualmente no hay información sobre el CAP en sujetos con factores de riesgo metabólico y que son atendidos en Atención Primaria de Salud. OBJETIVO: Estudiar la prevalencia de esteatosis hepática, estimada por CAP, en sujetos de la comunidad que presentan factores de riesgo metabólico y correlacionar los hallazgos con las características clínicas, bioquímicos y LS. RESULTADOS: Los sujetos con factores de riesgo tenían valores de CAP más altos que los del grupo control (268 ± 64 frente a 243 ± 49dB / m, p <0,001). La prevalencia de esteatosis severa (CAP> 280dB / m) en sujetos con factores riesgo fue del 43%. En el análisis multivariante, el índice de hígado graso (FLI) y el HOMA fueron factores predictivos independientes de esteatosis severa. Hubo una correlación directa entre los valores del CAP y los valores de FLI (r = 0.52, p <0.001). La prevalencia de LS fue del 12,6% en el grupo de riesgo vs 0% en el grupo control (p <0.001). El aumento de LS ocurrió predominantemente en sujetos con valores altos del CAP. CONCLUSIONES: Una alta proporción de sujetos con factores de riesgo metabólico visitados en atención primaria tienen valores de esteatosis severa. El FLI podría usarse como un sustituto del CAP. El aumento de LS se encontró en una proporción significativa de sujetos con factores de riesgo, pero no en los sujetos del grupo control.
BACKGROUND: Primary care is the ideal setting for early identification of patients with non- alcoholic fatty liver disease (NAFLD). NAFLD is a potentially progressive disease that may lead to cirrhosis and liver cancer but is frequently underrecognized because subjects at risk are often not evaluated. Controlled attenuation parameter (CAP) is a reliable method for non-invasive quantification of liver fat. It has the advantage of simultaneous measurement of liver stiffness (LS), an estimate of liver fibrosis. There is no information on CAP in subjects with risk factors from primary care. AIM: To investigate the prevalence of hepatic steatosis, as estimated by CAP, in subjects from the community with metabolic risk factors and correlate findings with clinical and biochemical characteristics and LS. PATIENTS AND METHODS: Population-based study of 215 subjects with metabolic risk factors without known liver disease identified randomly from a primary care center. A control group of 80 subjects matched by age and sex without metabolic risk factors was also studied. CAP and LS were assessed using Fibroscan. RESULTS: Subjects with risk factors had CAP values higher than those of control group (268±64 vs 243 ±49dB/m,p<0.001). Prevalence of severe steatosis (CAP> 280dB/m) in subjects with risk factors was 43%. In multivariate analysis, fatty liver index (FLI) and HOMA were independent predictive factors of severe steatosis. There was a direct correlation between CAP and FLI values (r = 0.52, p<0.001). Interestingly, prevalence of increased LS was 12.6% in the risk group vs 0% in the control group (p<0.001). Increased LS occurred predominantly in subjects with high CAP values. CONCLUSIONS: A high proportion of subjects with metabolic risk factors seen in primary care have severe steatosis. FLI could be used as a surrogate of CAP. Increased LS was found in a significant proportion of subjects with risk factors but not in control subjects.

The aim of this thesis was to generate "artificial" antibodies against a bioactive protein, GnSAF, produced by human ovarian granulosa cells that remains unidentified after 20 years of research. The library used in this study was a synthetic single-chain antibody scFv, Tomlinson J library. The antigen for biopanning was partially purified GnSAF. Screening the antibody clones from the library incorporated an additional selection step: an in vitro rat monolayer bioassay for GnSAF based on the specific suppression of GnRH-induced LH secretion. The initial screening with a binding ELISA technique resulted in 8 clones that were tested by bioassay, initially as pooled phage forms and subsequently as individual soluble scab forms. Three scabs recognised GnSAF bioactivity; with the suppression of GnRH-induced LH secretion by GnSAF-containing preparations reduced by up to 50% following incubation with the scabs. In order to improve the stability of the scabs for immunopurification purposes, and to widen the range of secondary labelled-antibodies available, the scabs were engineered into full length human immunoglobulins (IgG). One clone of the purified IgG form significantly altered GnSAF dose-response curves and demonstrated high affinity for GnSAF bioactivity when immobilised. When used for repeated immunopurification cycles and then Western blotted, this antibody enabled the isolation of a distinct band at around 66 kDa suggesting that this might be GnSAF. The main candidate molecules identified from the immunopurified material by excision of 2-D gel protein spots was a human serum albumin precursor and alloalbumin. This study demonstrates that the combination of bioassay and phage display technologies is a powerful tool in the study of uncharacterised proteins.

Chloroform (CF), tetrachloroethene (PCE) and trichloroethene (TCE) are dense chloro-aliphatic hydrocarbons (CAH) extensively used as industrial solvents. These compounds have been largely released to the environment due to poor waste management. In this thesis, the effect of a ZVI-PRB installed at a field site contaminated mainly with PCE, TCE and cis-DCE was evaluated. Moreover, a novel strategy to degrade the recalcitrant CF -alkaline hydrolysis induced by concrete-based recycled construction wastes- was proposed and developed in order to test its efficiency in degrading this pollutant. Compound specific isotope analysis (CSIA) is a valuable tool for monitoring an environmental treatment in the field, based on the isotope fractionation of an element during transformation reactions. Therefore, the general aim of this thesis is to use compound specific isotope analysis of 13C, 37Cl and 2H as a tool to assess both induced attenuation processes 1) chlorinated ethenes degradation by a ZVI-PRB installed at the field sited; and, 2) the proposed new remediation technique based on the use of concrete-based recycled construction wastes to degrade chloroform (CF) by alkaline hydrolysis applied at a site contaminated by this pollutant. First, laboratory experiments were conducted to study both ZVI and concrete effects on the chlorinated ethenes and the chloroform, respectively. ZVI experiments yielded carbon isotope fractionation values of the chlorinated ethenes degradation by the specific ZVI used in the field application, as well as, the first chlorine isotope fractionation values of TCE and cis-DCE associated to this reaction. Two promising approaches to discriminate the abiotic ZVI degradation versus biotic degradation present at the field site were brought forward 1) the dual isotope C-Cl approach, which distinguished slopes 4 times lower than for biodegradation of cis-DCE by the commercially available Dehalococcoides-containing culture mixed culture KB-1; and 2) the product-specific carbon isotope fractionation that showed a 10‰ difference between those products coming from β-dichloroelimination and hydrogenolysis reactions. Concrete experiments with CF achieved a 95% CF degradation after 28 d, accompanied by a significant carbon isotope fractionation. The carbon isotopic fractionation associated with alkaline hydrolysis of CF was -53±3‰. The obtained laboratory data permitted the assessment of the respective induced degradation treatments applied at the field site. At the site with the ZVI-PRB treatment, both, occurrence of biodegradation and degradation by ZVI-PRB were evidenced by means of detected metabolites and 13C data, with quantitative estimates of ZVI-PRB efficiency of less than 10% and 2% for PCE and cis-DCE, respectively. Dual element 13C-37Cl isotope plots confirmed that the effect of the ZVI-PRB was masked by biodegradation. Based on carbon isotopes data, 49% and almost 100% of PCE and TCE, respectively, were estimated to be removed by biodegradation. Finally the combination of 2H with 13C and 37Cl discriminated two different sources of contamination spilled from the same industry. This indicates the potential of δ2H to discriminate if a compound is of industrial origin, or whether it is formed as a daughter product during degradation. Regarding CF hydrolysis, field-scale pilot experiments were used to test the efficiency of the concrete-base recycled construction wastes to induce alkaline hydrolysis. The carbon isotopic fractionation obtained at the lab scale allowed the calculation of the percentage of chloroform degradation in the field-scale pilot experiments where alkaline conditions were induced in two recharge water interception trenches filled with concrete-based construction wastes. A maximum of approximately 30-40% of chloroform degradation was achieved. Although further research is required, the treatment of chloroform in groundwater through the use of concrete-based construction wastes is proposed. This strategy would also imply the recycling of construction and demolition wastes for use in value-added applications to increase economic and environmental benefits.
El chloroform (CF), el tetracloroetè (PCE) i el tricloretè (TCE) són hidrocarburs clor-alifàtics densos usats extensament com a solvents industrials. Aquests compostos s’han alliberat al medi degut a un tractament inadequat dels seus residus. En aquesta tesi, l’efecte d’una barrera permeable reactiva de ferro zero valent (BPR-FZV) instal•lada en un emplaçament contaminat majoritàriament amb PCE, TCE i cis-dicloretè (cis-DCE, subproducte de TCE) ha estat avaluada. A més a més, s’ha proposat i desenvolupat una nova estratègia per a degradar el CF, el qual és un compost recalcitrant, consistent en la inducció de la hidròlisi alcalina del CF mitjançant residus de construcció basats en formigó. L’ànàlisi isotòpic de compost específic (AICE) és una eina valuosa per al monitoreig d’un sistema de tractament medi ambiental, basant-se en el fraccionament isotòpic d’un element durant les reaccions de transformació. L’objectiu general d’aquesta tesi és l’ús de l’anàlisi isotòpic de compost específic de 13C, 37Cl i 2H com una eina per a controlar els dos processos d’atenuació 1) la degradació dels eten-clorats mitjançant una BPR-FZV instal•lada en el camp; i, 2) la nova tècnica de remediació de CF proposada basada en l’ús de residus reciclats de la construcció per tal d’induir la hidròlisi alcalina del CF. En general, mitjançant la combinació dels isòtops de C, Cl i H, aquesta tesi aporta noves eines per discriminar la degradació dels compostos organoclorats d’estudi mitjançant FZV, respecte la biodegradació en el camp, així com també per a identificar fonts de contaminació d’origen industrial o de productes formats, entre d’altres aportacions. A més a més, el nou mètode proposat per a degradar el CF basat en la seva hidròlisi alcalina mitjançant l’ús de residus de construcció reciclats ha demostrat ser eficient en la degradació d’aquest contaminant, així com també, mitjançant l’ús de isòtops de carboni, ha demostrat funcionar en experiments pilot monitorejats a escala de camp.

L'operon phest d'e. Coli code pour deux sous unite de la phenylalanyl-arnt synthetase. La transcription de cet operon est modulee par un mecanisme d'attenuation dependant du taux d'aminoacylation de l'arnt phe. La determination de la sequence nucleotidique des regions distales de l'operon a permis de mettre en evidence le gene hima transcrit dans la meme direction que phet, et demarrant seulement 7 nucleotides en aval de celui-ci. Hima est sous controle sos et autoregule. L'autoregulation de hima intervient via une modulation de l'activite des deux promoteurs: le promoteur principal, dont depend la transcription phest et le promoteur secondaire, interne phet. L'induction sos de l'expression de hima intervient au niveau des deux promoteurs. Ces controles impliquent un lien entre l'appareil de traduction et la reponse sos. Le controle hima par attenuation permet de coupler la synthese de son produit a l'etat fonctionnel de l'appareil de traduction

Thesis (M.S. in Systems Engineering Management)--Naval Postgraduate School, Sept. 2004.
Thesis Advisor(s): Kenneth L. Davidson. Includes bibliographical references (p. 83-85). Also available online.

Etude en laboratoire de roche par essais non destructifs. On s'interesse aux differentes causes d'attenuation d'une onde longitudinale. Pour des roches plutoniques, la diffraction sur grains domine; pour un calcaire cristallin, l'attenuation suit l'evolution du champ microfissural; pour une roche poreuse, l'attenuation est influencee par la dimension du milieu poreux; l'attenuation augmente par ailleurs avec l'alteration; essai sur une aplite

[EN] The test for determining the resonance frequencies has traditionally been used to investigate the mechanical integrity of concrete cores, to assess the conformity of concrete constituents in different accelerated durability tests, and to ascertain constitutive properties such as the elastic modulus and the damping factor. This nondestructive technique has been quite appealed for evaluation of mechanical properties in all kinds of durability tests. The damage evolution is commonly assessed from the reduction of dynamic modulus which is produced as a result of any cracking process. However, the mechanical behavior of concrete is intrinsically nonlinear and hysteretic. As a result of a hysteretic stress-strain behavior, the elastic modulus is a function of the strain. In dynamic tests, the nonlinearity of the material is manifested by a decrease of the resonance frequencies, which is inversely proportional to the excitation amplitude. This phenomenon is commonly referred as fast dynamic effect. Once the dynamic excitation ceases, the material undergoes a relaxation process whereby the elastic modulus is restored to that at rest. This phenomenon is termed as slow dynamics. These phenomena (fast and slow dynamics) find their origin in the internal friction of the material. Therefore, in cement-based materials, the presence of microcracks and interfaces between its constituents plays an important role in the material nonlinearity. In the context of the assessment of concrete durability, the damage evolution is based on the increase of hysteresis, as a result of any cracking process. In this thesis three different nondestructive techniques are investigated, which use impacts for exciting the resonant frequencies. The first technique consists in determining the resonance frequencies over a range of impact forces. The technique is termed Nonlinear Impact Resonant Acoustic Spectroscopy (NIRAS). It consists in ascertaining the downward resonant frequency shift that the material undergoes upon increasing excitation amplitude. The second technique consists in investigating the nonlinear behavior by analyzing the signal corresponding to a single impact. This is, to determine the instantaneous frequency, amplitude and attenuation variations corresponding to a single impact event. This technique is termed as Nonlinear Resonant Acoustic Single Impact Spectroscopy (NSIRAS). Two techniques are proposed to extract the nonlinear behavior by analyzing the instantaneous frequency variations and attenuation over the signal ring down. The first technique consists in discretizing the frequency variation with time through a Short-Time Fourier Transform (STFT) based analysis. The second technique consists of a least-squares fit of the vibration signals to a model that considers the frequency and attenuation variations over time. The third technique used in this thesis can be used for on-site evaluation of structures. The technique is based on the Dynamic Acousto- Elastic Test (DAET). The variations of elastic modulus as derived through NIRAS and NSIRAS techniques provide an average behavior and do not allow derivation of the elastic modulus variations over one vibration cycle. Currently, DAET technique is the only one capable to investigate the entire range of nonlinear phenomena in the material. Moreover, unlike other DAET approaches, this study uses a continuous wave source as probe. The use of a continuous wave allows investigation of the relative variations of the elastic modulus, as produced by an impact. Moreover, the experimental configuration allows one-sided inspection.
[ES] El ensayo de determinación de las frecuencias de resonancia ha sido tradicionalmente empleado para determinar la integridad mecánica de testigos de hormigón, en la evaluación de la conformidad de mezclas de hormigón en diversos ensayos de durabilidad, y en la terminación de propiedades constitutivas como son el módulo elástico y el factor de amortiguamiento. Esta técnica no destructiva ha sido ampliamente apelada para la evaluación de las propiedades mecánicas en todo tipo de ensayos de durabilidad. La evolución del daño es comúnmente evaluada a partir de la reducción del módulo dinámico, producido como resultado de cualquier proceso de fisuración. Sin embargo, el comportamiento mecánico del hormigón es intrínsecamente no lineal y presenta histéresis. Como resultado de un comportamiento tensión-deformación con histéresis, el módulo elástico depende de la deformación. En ensayos dinámicos, la no linealidad del material se manifiesta por una disminución de las frecuencias de resonancia, la cual es inversamente proporcional a la amplitud de excitación. Este fenómeno es normalmente denominado como dinámica rápida. Una vez la excitación cesa, el material experimenta un proceso de relajación por el cual, el módulo elástico es restaurado a aquel en situación de reposo. Este fenómeno es denominado como dinámica lenta. Estos fenómenos ¿dinámicas rápida y lenta¿ encuentran su origen en la fricción interna del material. Por tanto, en materiales basados en cemento, la presencia de microfisuras y las interfaces entre sus constituyentes juegan un rol importante en la no linealidad mecánica del material. En el contexto de evaluación de la durabilidad del hormigón, la evolución del daño está basada en el incremento de histéresis, como resultado de cualquier proceso de fisuración. En esta tesis se investigan tres técnicas diferentes las cuales utilizan el impacto como medio de excitación de las frecuencias de resonancia. La primera técnica consiste en determinar las frecuencias de resonancia a diferentes energías de impacto. La técnica es denominada en inglés: Nonlinear Impact Resonant Acoustic Spectroscopy (NIRAS). Ésta consiste en relacionar el detrimento que el material experimenta en sus frecuencias de resonancia, con el aumento de la amplitud de la excitación. La segunda técnica consiste en investigar el comportamiento no lineal mediante el análisis de la señal correspondiente a un solo impacto. Ésta consiste en determinar las propiedades instantáneas de frecuencia, atenuación y amplitud. Esta técnica se denomina, en inglés, Nonlinear Single Impact Resonant Acoustic Spectroscopy (NSIRAS). Se proponen dos técnicas de extracción del comportamiento no lineal mediante el análisis de las variaciones instantáneas de frecuencia y atenuación. La primera técnica consiste en la discretización de la variación de la frecuencia con el tiempo, mediante un análisis basado en Short-Time Fourier Transform (STFT). La segunda técnica consiste en un ajuste por mínimos cuadrados de las señales de vibración a un modelo que considera las variaciones de frecuencia y atenuación con el tiempo. La tercera técnica empleada en esta tesis puede ser empleada para la evaluación de estructuras in situ. La técnica se trata de un ensayo acusto-elástico en régimen dinámico. En inglés Dynamic Acousto-Elastic Test (DAET). Las variaciones del módulo elástico obtenidas mediante los métodos NIRAS y NSIRAS proporcionan un comportamiento promedio y no permiten derivar las variaciones del módulo elástico en un solo ciclo de vibración. Actualmente, la técnica DAET es la única que permite investigar todo el rango de fenómenos no lineales en el material. Por otra parte, a diferencia de otras técnicas DAET, en este estudio se emplea como contraste una onda continua. El uso de una onda continua permite investigar las variaciones relativas del módulo elástico, para una señal transito
[CAT] L'assaig de determinació de les freqüències de ressonància ha sigut tradicionalment empleat per a determinar la integritat mecànica de testimonis de formigó, en l'avaluació de la conformitat de mescles de formigó en diversos assajos de durabilitat, i en la terminació de propietats constitutives com són el mòdul elàstic i el factor d'amortiment. Esta tècnica no destructiva ha sigut àmpliament apel·lada per a l'avaluació de les propietats mecàniques en tot tipus d'assajos de durabilitat. L'evolució del dany és comunament avaluada a partir de la reducció del mòdul dinàmic, produït com resultat de qualsevol procés de fisuración. No obstant això, el comportament mecànic del formigó és intrínsecament no lineal i presenta histèresi. Com resultat d'un comportament tensió-deformació amb histèresi, el mòdul elàstic depén de la deformació. En assajos dinàmics, la no linealitat del material es manifesta per una disminució de les freqüències de ressonància, la qual és inversament proporcional a l'amplitud d'excitació. Este fenomen és normalment denominat com a dinàmica ràpida. Una vegada l'excitació cessa, el material experimenta un procés de relaxació pel qual, el mòdul elàstic és restaurat a aquell en situació de repòs. Este fenomen és denominat com a dinàmica lenta. Estos fenòmens --dinámicas ràpida i lenta troben el seu origen en la fricció interna del material. Per tant, en materials basats en ciment, la presència de microfissures i les interfícies entre els seus constituents juguen un rol important en la no linealitat mecànica del material. En el context d'avaluació de la durabilitat del formigó, l'evolució del dany està basada en l'increment d'histèresi, com resultat de qualsevol procés de fisuración. En esta tesi s'investiguen tres tècniques diferents les quals utilitzen l'impacte com a mitjà d'excitació de les freqüències de ressonància. La primera tècnica consistix a determinar les freqüències de ressonància a diferents energies d'impacte. La tècnica és denominada en anglés: Nonlinear Impact Resonant Acoustic Spectroscopy (NIRAS). Esta consistix a relacionar el detriment que el material experimenta en les seues freqüències de ressonància, amb l'augment de l'amplitud de l'excitació. La segona tècnica consistix a investigar el comportament no lineal per mitjà de l'anàlisi del senyal corresponent a un sol impacte. Esta consistix a determinar les propietats instantànies de freqüència, atenuació i amplitud. Esta tècnica es denomina, en anglés, Nonlinear Single Impact Resonant Acoustic Spectroscopy (NSIRAS). Es proposen dos tècniques d'extracció del comportament no lineal per mitjà de l'anàlisi de les variacions instantànies de freqüència i atenuació. La primera tècnica consistix en la discretización de la variació de la freqüència amb el temps, per mitjà d'una anàlisi basat en Short-Time Fourier Transform (STFT). La segona tècnica consistix en un ajust per mínims quadrats dels senyals de vibració a un model que considera les variacions de freqüència i atenuació amb el temps. La tercera tècnica empleada en esta tesi pot ser empleada per a l'avaluació d'estructures in situ. La tècnica es tracta d'un assaig acusto-elástico en règim dinàmic. En anglés Dynamic Acousto-Elastic Test (DAET). Les variacions del mòdul elàstic obtingudes per mitjà dels mètodes NIRAS i NSIRAS proporcionen un comportament mitjà i no permeten derivar les variacions del mòdul elàstic en un sol cicle de vibració. Actualment, la tècnica DAET és l'única que permet investigar tot el rang de fenòmens no lineals en el material. D'altra banda, a diferència d'altres tècniques DAET, en este estudi s'empra com contrast una ona contínua. L'ús d'una ona contínua permet investigar les variacions relatives del mòdul elàstic, per a un senyal transitori. A més, permet la inspecció d'elements per mitjà de l'accés per una sola cara.
Eiras Fernández, JN. (2016). Studies on nonlinear mechanical wave behavior to characterize cement based materials and its durability [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/71439
TESIS
Premiado

La résistance aux antimicrobiens est l’un des défis majeurs du XX1eme siècle. Pseudomonas aeruginosa est inscrit sur la liste des organismes pathogènes qui deviennent résistants aux antibiotiques conventionnels. De nouvelles stratégies visant à atténuer la virulence sans perturber la croissance et la viabilité bactériennes, également connues sous le nom de stratégie anti-virulence, sont développées. Les plantes sont connues pour produire de nombreux métabolites secondaires. Des extraits de fruits de Pistachia Lentiscus originaires d'Algérie et de 40 extraits de plantes originaires du Nord-Chili ont été criblés pour leur capacité à atténuer la production de la pyocyanine, un facteur de virulence majeur de P. aeruginosa, dans le but d’évaluer leur potentiel effet antivirulence. Les extraits sélectionnés (Pistacia lentiscus, Azorella atacamensis, Baccharis grisebachii, Haplopappus rigidus et Parastrephia terestiucula), ont été fractionnés et l’ensemble de ces extraits et fractions a montré une atténuation de la production d’autres facteurs de virulence (élastase, rhamnolipides), qui a pu être attribuée, au moins partiellement à une diminution de la communication bactérienne via le mécanisme du quorum sensing. Ces extraits et fractions altèrent également la fluidité membranaire de P. aeruginosa. Cet effet anti-virulence a été validé dans un modèle d'infection cellulaire, et sur le nématode Caenorhabditis elegans. Dans toutes ces conditions, la croissance de P. aeruginosa n'a pas été affectée. Un profilage chimique des extraits et fractions de P. lentiscus et d'A atacamensis a révélé la présence d'acide gingkolique et de diterpenoides de type azorellane/mulinane comme potentiels composés bioactifs. De futures études visent à identifier les composés bioactifs sur P. aeruginosa H103, ainsi que sur un panel de souches cliniques, et à évaluer un potentiel effet potentialisateur de l'activité des antibiotiques. Ces travaux visent in fine à proposer ces composés d’origine végétale comme adjuvants dans le traitement des infections à P. aeruginosa
Antimicrobial resistance has become a great challenge in therapeutic medicine so much so that the World health organization forecasts the possibility of a post-antibiotic era where minor injuries may lead to mortality. Pseudomonas aeruginosa is among the list of organisms that are highly resistant to conventional antibiotics, partly due to its broad genome, which facilitates the elaboration of virulence determinants and rapid adaptation to various environments, in addition to its inherent resistance mechanisms. In view of this, alternative measures of controlling microbial virulence activities using novel approaches that do not disturb its growth and viability, also known as anti-virulence strategy, are gaining wider attention. Since plants are repositories of several metabolites with chemical defense system against environmental pathogens, through ethnobotanical led studies, the effect of Pistacia lentiscus fruit extracts originating from Algeria and forty plant extracts originating from North-Chile were biologically and chemically evaluated with the aim of deciphering their anti-virulence effects against P. aeruginosa. Furthermore, this study tried to gain more insight into the bioactive compounds and possible mechanism of action. From the results obtained, selected plant extracts attenuated P. aeruginosa mainly pyocyanin activity and /or elastase and rhamnolipids virulence production which appears to be associated with the inhibition of quorum sensing activities and the alteration in membrane activities. The anti-virulence effect of the selected extracts (P. lentiscus, Azorella atacamensis, Baccharis grisebachii, Haplopappus rigidus and Parastrephia terestiucula) were also validated in biological models of infections where they mediated the toxicity of P. aeruginosa towards A549 human monolayer cells and/or Caenorhabditis elegans nematode. Interestingly, growth of the pathogen was not affected. Further chemical profiling of P. Lentiscus, and A atacamensis extracts revealed the presence of gingkolic acid and azorellane/mulinane diterpenoids as the putative bioactive compounds. Future studies intend to explore these extracts and their derived compounds on the potentiation of antibiotic activity in a panel of clinical strains. In general, this study sets the pace for the possible use of these plant extracts as adjuvants in treatment of P. aeruginosa infections

博士
國立中山大學
電機工程學系研究所
98
This thesis first discusses the ground plane effects of a test site on the antenna factors (AFs) of hybrid antenna (biconical log-periodic dipole array). Meanwhile, the effects of mutual coupling between antenna and its image, and the variation of active phase center are also discussed. From these analyses, a hybrid method, based on the modified SSM (Standard Site Method) and the PCPM (Phase Center and Pattern Matching) applied to the hybrid antenna for NSA (Normalized Site Attenuation) measurement is proposed. By this method, the low geometry- dependent AFs of hybrid antenna can be obtained to produce more reasonable NSA values for a test site. Secondly, this thesis proposes a simple, fast, and accurate method to calibrate the free-space AFs of broadband EMC (Electromagnetic Compatibility) antennas. This method adopts a fixed-height configuration and a MUSIC (MUltiple SIgnal Classification) algorithm. This configuration significantly shortens measurement time and removes height-dependent calibration errors. Meanwhile, the MUSIC algorithm can remove unexpected reflections from the ground plane or any other reflecting objects, by which the free-space AFs can be calculated. In addition, this method can also automatically compensate for the phase center shift, which makes measurement easier and more convenient. To verify this method, the calibrated results are compared with other published standard methods: the mean differences can be as low as 0.25 dB for the LPDA (log-periodic dipole array), 0.42 dB for the hybrid antennas, and 0.36 dB for the horn antennas. Finally, this thesis provides a method of using two equivalent negative inductances from two terminals of three coupled inductors to reduce the parasitic inductances of a typical three-capacitor EMI (Electromagnetic Interference) filter. Theoretical analysis and formula deduction for the design of two equivalent negative inductances are demonstrated. The experimental results show that the insertion losses of a three-capacitor EMI filter at 50 MHz can be reduced by 16.8 dB for the DM (differential-mode) and by 19.2 dB for the CM (common-mode). In Appendix A of this thesis, an extended study of the effect of ground plane on antenna’s radiation is described. A simple V-shape edge-groove design for a finite ground plane can effectively reduce the pattern ripples of a monopole. The optimal design of proposed structure can reduce the peak-to-peak pattern ripples from 26 to 4.5 dB.

碩士
國立臺灣大學
應用力學研究所
104
Ultrasonic system, the widely used in clinical diagnosis, is providing the relatively convenient, instantaneity, non-invasion and low cost than MRI, CT, etc. Besides, the assessment of backscattering signal processing on tissue parameters by quantitative analysis have become increasingly popular recently. Based on the above reasons, the spectral shift method is proposed by using the short-time Fourier transform to estimate the ultrasonic attenuation coefficients which is an important issue for clinical diagnosis. Investigating the influence of system factors by proposed method is the main concept of this study, e.g. evaluate the patient’s fatty liver condition by observing the variation tendency of the ultrasonic attenuation coefficients. There are two parts in this study: 1. the graphite phantom experiment and 2. the clinical experiment based on the results of phantom experiment. In the former experiment, the measured standard attenuation coefficients were compared with the results of the spectral shift method in three system factors adjustments, the center frequency of ultrasonic transducer, diffraction compensation, and Time Gain Compensation (TGC). Measurement results showed that the attenuation coefficient increased with high fatty concentration. The characteristics of high frequency with high attenuation was verified because the failing slope of center frequency were increased with larger center frequency of transducer. To precisely improve the estimated attenuation coefficients, the diffraction calibration of the beam focal effects caused by the transducer in acoustic transfer is involved. Experimental results showed that no matter the convex transducer or the linear transducer, the accuracy of modified attenuation coefficients have significantly improved. To have better image visualization of B-Mode, the TGC will be opened to identify the deeper region in the clinical. It was frequently investigated that the attenuation coefficients of the N-TGC estimated have better accuracy than the TGC. Clinical experiment on fatty liver is the second part of this study. It was discovered that the attenuation coefficients of TGC estimated is higher than N-TGC; however, in the ROC curve analysis, the results of TGC estimated is lower than N-TGC. To sum up, lower center frequency of ultrasonic transducer, diffraction calibration, and N-TGC are the three beset system factors to identify the mild and moderate fatty liver in clinical applications.

Thesis (M.S.)--State University of New York at Buffalo, 2008.
Title from PDF title page (viewed on Jan. 22, 2009) Available through UMI ProQuest Digital Dissertations. Thesis adviser: Rabideau, Alan Includes bibliographical references.

The linear attenuation coefficient and buildup factor are a few of the important characteristics that need to be studied and determined prior to using a material clinically in radiation treatment and protection. The linear attenuation coefficient and buildup factor, as well as several other properties, will be determined for MCP-96 alloy to assess its use in radiation therapy. A narrow collimated beam of γ-rays from sources with varying energies will pass through various thicknesses of MCP-96 alloy. The attenuation in the intensity of the beam will be determined for each varying thickness of the alloy. Plotting the thickness of the alloy versus the corresponding logarithmic intensity of the beam will allow calculation of the linear attenuation coefficient. The narrow beam geometry will then be replaced by the broad beam geometry to determine the buildup factor. Additional radiation is obtained through the broad beam geometry as a result of scattering and secondary radiation. Comparing the broad beam geometry to the narrow beam geometry allows determination of the buildup factor. Since the buildup factor depends upon the thickness of the MCP-96 attenuator, the energy of the beam, and the source-to-attenuator (STA) distance, it will be calculated using three parameters. It will be calculated as a function of thickness of MCP-96 alloy by using various thicknesses of the alloy; as a function of the energy of the incident radiation beam by using several sources with different beam energies; and finally, as a function of the source-to-attenuator distance by changing the position of the MCP-96 attenuators.
Department of Physics and Astronomy

碩士
國立中興大學
食品暨應用生物科技學系所
98
Lycopene has been shown to inhibit tumor proliferation and metastasis as well as induce cancer cell apoptosis. However, little attention has been paid on the anti-angiogenic effect of lycopene. In this study, we employed the human umbilical vein endothelial cells (HUVECs) to investigate the anti-angiogenic effect of lycopene and the possible mechanisms of action. Lycopene (2.5-20 μM) slightly affected the proliferation of HUVEC cells for incubation of 12 and 24 h. Incubation of HUVEC cells with lycopene for 6, 12 and 24 h significantly inhibited the tube formation, and the effect was strongest at 6 h of incubation. Results revealed that lycopene significantly: 1) inhibited the invasion, migration and adhesion of HUVEC cells; 2) decreased the activities of matrix metalloproteinase-2 (MMP-2) and urokinase-type plasminogen activator (uPA); 3) increased the protein expression of tissue inhibitors of metalloproteinase-2 (TIMP-2), plasminogen activator inhibitor-1 (PAI-1) and nonmetastatic protein 23 homologue 1 (nm23-H1). In addition, incubation of HUVEC cells with lycopene (10 μM) for 2, 4 and 6 h showed that lycopene significantly: 1) inhibited the protein expression of the vascular endothelial growth factor receptor-2 (VEGFR-2) at 2 h of incubation; 2) down-regulated the phosphorylation of ERK 1/2 and p38 at 4 h of incubation; 3) diminished the protein expression of PI3K and the phosphorylation of Akt at 6 h of incubation. The present study is the first to demonstrate that the anti-angiogenic effect of lycopene on HUVEC cells involves the attentenuation of VEGFR-2 signaling pathway followed by inhibition of extracellular matrix (ECM) degradation, tube formation and cell migration, leading to reduced angiogenesis.

碩士
輔仁大學
基礎醫學研究所碩士班
104
Acute inflammation companied with the exacerbation of various lung pathologies such as acute lung injury (ALI). Lipopolysaccharide (LPS), the component of bacterial cell wall, was released after bacteria dead. LPS modulated lung inflammation via up-regulation the expression of intercellular adhesion molecule-1 (ICAM-1), cytosolic phospholipase A2 (cPLA2) and cyclooxygenase-2 (COX-2). Additionally, the release of tumor necrosis factor-α (TNF-α) was the characteristic of microbial infection-induced ALI. TNF-α acted as a pleiotropic cytokine involving in inflammatory responses. Thus, expression and actions of ICAM-1, cPLA2 and COX-2 contributed to LPS- and TNF-α-regulated lung inflammation, and manipulating the expression of these genes may provide beneficial effects on treatment of pulmonary pathologies. On the other hand, melatonin, synthesized by the pineal gland, played key roles in regulating circadian rhythms. More and more reports suggested that melatonin exerted various biological effects, such as antioxidant, anticancer, anti-inflammatory, immunomodulatory. However, whether application of melatonin attenuated lung inflammation of pulmonary pathologies remained largely unknown. Thus, the objective of this work is to establish the actions of melatonin on manipulating lung inflammation. We found that pretreatment of melatonin significantly attenuated mRNA expression of ICAM-1, cPLA2 and COX-2 in LPS- and TNF-α-stimulated A549 cells. Moreover, LPS and TNF-α significantly enhanced intracellular accumulation of reactive oxygen species (ROS), which was reversed by melatonin. LPS or TNF-α-activated p47phox subunit of NADPH oxidase was downregulated by melatonin, suggested that melatonin modulated intracellular ROS balance via modulating NADPH oxidase activity. In ICR mice, intra-tracheal injection of LPS and TNF-α significantly enhanced the expression of inflammatory proteins and accumulation of leukocytes in lung. Pre-treatment of melatonin (i.p.) attenuated LPS and TNF-α effects in ICR mice. In addition, melatonin was found to modulate the expression of surfactant A (SP-A) and SP-D in LPS- and TNF-α-treated mice. Taken together, we found that melatonin attenuated LPS- and TNF-α-regulated lung inflammation via reduce intracellular ROS together with expression of ICAM-1, cPLA2 and COX-2.

碩士
國立中山大學
電機工程學系研究所
91
The CISPR of IEC in European and the ANSI in American use the model of site attenuation to evaluate and quantify the quality of OATS. The ANSI also uses the concept of Normalized Site Attenuation (NSA) to eliminate the effects brought about by different antennas, which may cause the inaccuracy of site attenuation. To stringently require the quality of OATS, the measured values of NSA have to be compared with the theoretical ones. If their differences are within (+/-)4 dB at all frequencies, the test environment of the OATS can be accepted. At present, the theoretical values of NSA are used as a standard for verifying the OATS in the world. However, many non-ideal factors derived from certain assumptions and simplifications of the NSA may cause the measured NSA to deviate from the theoretical values. To understand the manner and extent of the effects, in this thesis we find out the non-ideal factors by studying the NSA by numerically simulating the effects of each factor on NSA measurement by the method of moment (MoM), and the results are analyzed and discussed. We find that there is a difference of 6 dB on the NSA when the impedance of the receive antenna is mismatched. Meanwhile, we also study the relationship between the conductivity of non-perfect electrical conductor and the ideal value of NSA. We conclude that a ground plane made by metal can be regarded as a PEC one. However, the values of NSA will increase if the conductivity of ground plane is below 1000 S/m. Besides, considering the humid Taiwan climate in particular, we investigate the condition of a thin layer of water covering the ground plane after rain and the results show that the effect of the water plane will decrease the values of NSA. As for the measurement at a distance of 3 m, a deviation of 2 dB at low frequencies arises from the effect of near field for the case of horizontal polarization. Finally as for the non-conducting table in OATS, our results show that the larger values of relative permittivity and conductivity of table result in the larger change of NSA value. The difference can be 3 dB for the case with a wooden table. With results of our research, the effects of non-ideal factors on NSA measurement can be comprehended clearly. The comparison of the differences also can be used as a reference for the modification of the NSA measurement in the future.

碩士
國立中興大學
食品暨應用生物科技學系所
101
Angiogenesis, the process of vascular growth by sprouting of pre-existing vessels, plays an important role in many physiological and pathological processes. Vascular endothelial growth factor receptor-2 (VEGFR2) is a specific tyrosine kinase receptor and is involved in cell proliferation, invasion and migration in vascular endothelial cells. Intergrin β1, a cell adhesion molecule that is expressed on the endothelial cell surface, plays an important role in cell migration, proliferation, differentiation and survival of endothelium. 2-Deoxyglucose (2-DG), a synthetic non-metabolizable analogue of glucose, can interfere with glycolysis and N-linked glycosylation by competition with glucose and mannose metabolism, respectively. The interference of 2-DG with N-linked glycosylation has been shown to induce unfolded protein response in endoplasmic reticulum resulting in promotion of apoptosis and inhibition of angiogenesis in human umbilical vascular endothelial cells (HUVECs). However, the anti-angiogenic mechanisms of 2-DG are not well-investigated, it is unclear whether the anti-angiogenic activity of 2-DG is related to VEGFR2- and integrin β1-mediated pathways involved in extracellular matrix (ECM) degradation, cell migration and differentiation in vascular endothelial cells. In this study, we employed an ex vivo rat aortic rings assay to substantiate the anti-angiogenic action of 2-DG and investigated the molecular mechanism underlying such actions in HUVECs. Results reveal that rat aortic rings treated with 2-DG (0.05-1 mM) for 7 d resulted in a significant inhibition of new blood formation, with an inhibition of 40% (P < 0.05) at 1 mM of 2-DG. 2-DG (0.1-1 mM) also significantly inhibited tube formation, invasion, migration and adhesion of HUVECs in a concentration-dependent manner at 24 h of incubation, with an inhibition of 50%, 58%, 55% and 26% (P < 0.05) at 1 mM 2-DG, respectively. In addition, 2-DG significantly inhibited mRNA and protein expression of VEGFR2 as well as protein expression of integrin β1. Meanwhile, VEGFR2 tended to shift to low molecular weight position by 2-DG treatment. Mechanistically, 2-DG significantly inhibited VEGFR2- and integrin β1-mediated signaling pathways, such as: (1) phosphorylation of focal adhesion kinase (FAK) followed by attenuated PI3K-Akt axis, leading to inhibited protein expression of Rho small GTPase (Rho and Rac1); (2) phosphorylation of p38; (3) mRNA, protein expression and activity of matrix metalloproteinase-2 (MMP-2) and (4) protein expression of tissue inhibitor of metalloproteinase-2 (TIMP-2). In addition, mannose (2 mM) reversed the effects of 2-DG on tube formation, MMP-2 avtivity as well as on VEGFR2 and integrin β1 protein expression in HUVECs. We then employed immunofluorescence assay to illustrate the effects of 2-DG on VEGFR2 distribution in HUVECs. Results reveal that pre-incubation of HUVECs with 2-DG (1 mM) for 24 h clearly induced accumulation of VEGFR2 on endoplasmic reticulum, whereas co-incubation with mannose (2 mM) significantly reversed such an accumulation. In conclusion, the present study demonstrats that 2-DG has anti-angiogenic activity which involves attenuating of VEGFR2- and integrin β1-mediated signaling pathways as well as interference of N-linked glycosylation.