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Arrayago, Luquin Itsaso. "New approach for efficient design of stainless steel RHS and SHS elements." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/398697.
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This thesis investigates the cross-section and member behaviour of cold-formed stainless steel RHS and SHS elements and proposes an alternative and more efficient design approach. Combined with aesthetic appeal, exceptional mechanical properties and excellent corrosion and fire resistances, efficient design methods present stainless steel as an attractive alternative to the usual carbon steel for structural applications.
Exhaustive studies of the nonlinear stress-strain behaviour and the analytical modelling of the response are presented for different stainless steel alloys. The study was based on 600 experimental stress-strain curves obtained from the literature and complemented with 42 tensile coupon tests. Although the material model currently included in Annex C of EN1993-1-4 (2006) was found to accurately represent the measured stress-strain curves for the different stainless steel grades and material types, revised equations were proposed for the strain hardening parameters n and m and for the ultimate tensile stress and strain for ferritics.
A comprehensive experimental programme on five cross-sections of ferritic stainless steel grade 1.4003 tubular elements is also described. The actual geometry and initial geometric imperfections were carefully measured and the material response of flat and corner regions of each section were characterized by conducting 20 tensile tests on coupons extracted from the cross-sections. The cross-sectional behaviour was investigated through 10 stub column tests under pure compression and 16 subjected to combined loading conditions, while 8 beams were tested under four-point bending configuration and 4 subjected to three-point bending loading conditions. At member level, the bending moment redistribution capacity of ferritic continuous beams was investigated by conducting 9 five-point bending tests. Finally, 12 tests were conducted on ferritic stainless steel columns to determine the behaviour of members subjected to concentric and eccentric compression loads. Additional data on austenitic, ferritic and duplex stainless steel elements was generated from parametric studies based on finite element models validated from the conducted experiments.
The assessment of the codified design expressions was derived by comparing experimental and numerical strengths with the calculated resistance predictions for stainless steel cross-sections and members subjected to different loading conditions. Results demonstrated that predictions are noticeably conservative for stocky and slender cross-sections since enhanced material properties are not considered and the susceptibility of cross-sections to local buckling is underestimated. Thus, a full slenderness range Direct Strength Method (DSM) approach was proposed for stainless steel RHS and SHS cross-sections and members based on the same strength curve for all loading conditions. The proposed approach was found to be more accurate for cross-sections, columns and beam-columns since strain hardening effects are incorporated and due to the fact that the actual stress distribution of the cross-section is considered when determining the slenderness. The reliability of the approach was demonstrated by statistical analyses, enabling its use in structural design standards.
Finally, the applicability of design approaches based on plastic analysis to stainless steel continuous beams was assessed. The analysis of continuous beam strengths demonstrated that capacity predictions based on the first hinge formation result in a considerable overconservatism and that traditional plastic design can be safely applied with the Class 1 cross-section limit provided in EN1993-1-4 (2006). However, it was also statistically demonstrated that the best capacity predictions are obtained for design methods including both bending moment redistribution and strain hardening effects, such as the Continuous Strength Method for indeterminate structures or the proposed DSM-based approach.Esta tesis trata sobre el comportamiento de perfiles tubulares conformados en fío de acero inoxidable y propone expresiones de diseño alternativas y más eficientes. Un diseño eficiente de las estructuras de acero inoxidable, junto con sus adecuadas propiedades mecánicas y resistencia a la corrosión, hacen de este material una atractiva alternativa frente al acero al carbono para aplicaciones estructurales. Se ha realizado un estudio exhaustivo del comportamiento tensodeformacional de diferentes tipos de acero inoxidable, así como de los modelos analíticos que caracterizan su comportamiento. El estudio se basa en más de 600 curvas experimentales de material extraídas de la literatura y complementadas con 42 ensayos. Los resultados ponen en evidencia que el modelo material actualmente recogido en el Anejo C de la EN1993-1-4 (2006) representa adecuadamente el comportamiento tensodeformacional de diferentes grados y tipos de material. No obstante, se han propuesto nuevas expresiones para la determinación de los coeficientes de no linealidad n y m, así como para la predicción de la resistencia y deformación últimas de los aceros inoxidables ferríticos. La tesis también describe una campaña experimental en elementos tubulares de acero inoxidable ferrítico EN1.4003. Tras la medición de la geometría e imperfecciones iniciales, se procedió a la caracterización del comportamiento de las regiones planas y de esquina mediante 20 ensayos de material. El comportamiento seccional se ha estudiado mediante 10 ensayos de elementos cortos a compresión y 16 sometidos a flexocompresión, realizando también 8 ensayos sobre vigas biapoyadas sometidas a flexión pura y 4 sometidas a gradientes de flexión. El comportamiento a nivel de elemento se ha caracterizado mediante 12 ensayos de pilares sometidos a compresión y flexocompresión y el estudio sobre la capacidad de redistribución de estructuras de acero inoxidable ferrítico se ha basado en 9 vigas continuas. El comportamiento de los grados austeníticos, ferríticos y duplex se ha estudiado también mediante los modelos de elementos finitos previamente validados a partir de los ensayos realizados. La valoración de las expresiones de diseño actualmente recogidas en las diferentes normativas se ha llevado a cabo mediante la comparación de los resultados numéricos y experimentales con las cargas predichas para diferentes estados de carga. Dichos resultados han puesto de manifiesto que las resistencias predichas por las normativas son considerablemente conservadoras tanto para secciones robustas como esbeltas, puesto que no se tienen en cuenta los efectos de endurecimiento por deformación y el comportamiento de abolladura no está correctamente caracterizado. Por consiguiente, se ha propuesto un nuevo método de diseño basado en el Direct Strength Method (DSM) para secciones y elementos de acero inoxidable, aplicable en todo el rango de esbelteces y que emplea una misma curva de resistencia para los distintos casos de carga. Se ha demostrado que la nueva propuesta proporciona mejores resultados tanto a nivel seccional como en elementos y su fiabilidad se ha demostrado mediante el correspondiente análisis estadístico, permitiendo su inclusión en las normativas de diseño. Por último, se ha estudiado la aplicabilidad de los métodos de diseño basados en el cálculo global plástico en vigas continuas de acero inoxidable. El estudio ha demostrado que pese a que la consideración de métodos basados en cálculos elásticos proporciona resultados notablemente conservadores, los métodos tradicionales de diseño plástico pueden ser utilizados junto con la definición de Clase 1 actualmente recogida en EN1993-1-4 (2006). No obstante, también se ha demostrado que la mejor predicción de resistencia viene dada por aquellos métodos que incorporan tanto la redistribución de esfuerzos como los efectos de endurecimiento por deformación, como son el Continuous Strength Method o el método propuesto basado en el DSM
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Brahmachari, Koushik, of Western Sydney Hawkesbury University, of Science Technology and Agriculture Faculty, and School of Construction and Building Sciences. "Connection and flexural behaviour of steel RHS filled with high strength concrete." THESIS_FTA_CBS_BRAHMACHARI_K.xml, 1997. http://handle.uws.edu.au:8081/1959.7/526.
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Steel hollow section members filled with concrete have been frequently used in recent construction industry as columns and beams and beam-columns because of their superior performance and constructability. Previous research demonstrated that such system has large energy absorption capacity which is critical in the event of an earthquake. By filling steel RHS with concrete, the failure of the steel shell due to local buckling can be delayed and the ductility of the concrete core can be improved as a result of the confinement of the steel shell. This type of composite section may be used in various structures including frames of high rise buildings, bridges, offshore structures, cast-in-situ piles in foundation etc. Design methods for concrete-filled steel tubular sections are recommended in a number of code of practices. Due to the significant differences in the material properties between normal strength concrete and high strength concrete, there is a need to study the behaviour of composite sections with higher strength concretes. The study emphasises ultimate strength, ductility, post-failure strength reserve and interface bond. It also emphasises ductility and post-failure strength of the composite beams due to the brittle behaviour of higher strength concretes when compared to normal strength concrete. Spreadsheet graph were used to present the results such as load versus strains, load versus deflections etc. In this thesis analytical study is presented on the calculation of ultimate moment of resistance of the concrete-filled RHS beams. Among the main considerations of the derivation, the steel portion was assumed either elastic-perfectly plastic or perfectly plastic and concrete carries no strength in the tensile zone. At the interface both full bond and partial bond were assumed for comparison. Efforts were also made to calculate the midspan deflections of the composite beams. Simple analytical expressions derived from this study can be coded to a prgrammable calculator or in a small spreadsheet program for design use. Finite element studies were carried out by using a proprietorship software package ANSYS. In the analysis of concrete-filled, three types of elements with large deformation and nonlinear capabilities were used. A plastic shell element, a solid concrete element with cracking and crushing capabilities, and a nonlinear spring contact element were used to model the steel shell, the concrete core and the interface respectively.Doctor of Philosophy (PhD)
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Wu, Jian. "Numerical modelling and optimization of new RHS column-to-I beam connections." Thesis, Swansea University, 2013. https://cronfa.swan.ac.uk/Record/cronfa43170.
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Koch, Douglas J. "Positioning the Reserve Headquarters Support (RHS) system for multi-layered enterprise use." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep%5FKoch.pdf.
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Thesis (M.S. in Information Technology Management)--Naval Postgraduate School, September 2009.Thesis Advisor(s): Cook, Glenn. "September 2009." Description based on title screen as viewed on 6 November 2009. Author(s) subject terms: Enterprise architecture, project management, business process transformation, operating model, IT governance, IT systems, data quality, data migration, business operating model, personnel IT systems, HRM, ERP. Includes bibliographical references (p. 89-92). Also available in print.
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Brahmachari, Koushik. "Connection and flexural behaviour of steel RHS filled with high strength concrete." Thesis, View thesis, 1997. http://handle.uws.edu.au:8081/1959.7/526.
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Steel hollow section members filled with concrete have been frequently used in recent construction industry as columns and beams and beam-columns because of their superior performance and constructability. Previous research demonstrated that such system has large energy absorption capacity which is critical in the event of an earthquake. By filling steel RHS with concrete, the failure of the steel shell due to local buckling can be delayed and the ductility of the concrete core can be improved as a result of the confinement of the steel shell. This type of composite section may be used in various structures including frames of high rise buildings, bridges, offshore structures, cast-in-situ piles in foundation etc. Design methods for concrete-filled steel tubular sections are recommended in a number of code of practices. Due to the significant differences in the material properties between normal strength concrete and high strength concrete, there is a need to study the behaviour of composite sections with higher strength concretes. The study emphasises ultimate strength, ductility, post-failure strength reserve and interface bond. It also emphasises ductility and post-failure strength of the composite beams due to the brittle behaviour of higher strength concretes when compared to normal strength concrete. Spreadsheet graph were used to present the results such as load versus strains, load versus deflections etc. In this thesis analytical study is presented on the calculation of ultimate moment of resistance of the concrete-filled RHS beams. Among the main considerations of the derivation, the steel portion was assumed either elastic-perfectly plastic or perfectly plastic and concrete carries no strength in the tensile zone. At the interface both full bond and partial bond were assumed for comparison. Efforts were also made to calculate the midspan deflections of the composite beams. Simple analytical expressions derived from this study can be coded to a prgrammable calculator or in a small spreadsheet program for design use. Finite element studies were carried out by using a proprietorship software package ANSYS. In the analysis of concrete-filled, three types of elements with large deformation and nonlinear capabilities were used. A plastic shell element, a solid concrete element with cracking and crushing capabilities, and a nonlinear spring contact element were used to model the steel shell, the concrete core and the interface respectively.
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Brahmachari, Koushik. "Connection and flexural behaviour of steel RHS filled with high strength concrete /." View thesis, 1997. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030708.160244/index.html.
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Thesis (Ph. D.)--University of Western Sydney, Hawkesbury."Thesis presented for the Degree of Doctor of Philosophy, School of Construction and Building Sciences, Faculty of Science, Technology and Agriculture, University of Western Sydney, Hawkesbury, December 1997.
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Cifuentes, Catalina, and Emelie Tirmén. "Utbildning kontra arbetslivserfarenhet- En undersökning om hotell- och restaurangbranschen samt RHS studenters åsikterDatum:." Thesis, Örebro universitet, Restaurang- och hotellhögskolan - Grythytte Akademi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-19769.
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Bakgrund: Hotell- och restaurangbranschen är dålig på att anställa personer med eftergymnasiala utbildningar med inriktning på hotell och restaurang, de prioriterar istället individer som har mycket arbetslivserfarenhet. Det beror på att branschen är praktisk och att åsikten att yrkeskunskapen kan läras ut på golvet fortfarande är stark.Syftet: Syftet är att undersöka hur studenter som examinerades 2010 från Restaurang- och hotellhögskolan (RHS) i Grythyttan Örebro Universitet, uppfattar den utbildningen de genomgått. Metod: Dessutom kommer uppsatsen innehålla åsikter och tankar från före detta studenter som examinerades sommaren 2010 från Restaurang- och hotellhögskolan (RHS) i Grythyttan, Örebro universitet. Resultatet bygger på tre intervjuer med yrkesverksamma personer från hotell- och restaurangbranschen, samt tio besvarade enkäter från före detta studenter från RHS. Resultatet: visar på att hotell- och restaurangbranschen prioriterar arbetslivserfarenhet före eftergymnasiala utbildningar dock är utbildning viktigt för att arbeta sig upp inom företaget. De tidigare studenterna instämmer och anser att RHS utbildningar bör utveckla sina ledarskapskurser för att studenterna ska få större möjligheter inom hotell- och restaurangbranschen. Slutsats: Om en individ vill arbeta sig upp inom hotell- och restaurangbranschen går det snabbare om personen har en universitet/ högskoleutbildning i bagaget.
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Omair, Moayad R. "The behaviour of welded T-end plate connections to rectangular hollow section (RHS)." Thesis, Coventry University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313163.
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Ibrahim, Azmi. "Behaviour of unstiffened and bolt-stiffened RHS beams under combined bending moment and concentrated force." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240405.
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Ow, Yong Lai Meng. "Policy transfer and translation : integrated care development in SingHealth (SGH campus) Regional Health System (RHS) in Singapore." Thesis, University of Bristol, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.743041.
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Mohan, Meera. "Connections in higher strength Grade C450 cold formed rectangular hollow sections." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/24333.
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CIDECT guidelines for hollow steel joints were mainly based on research of ductile steel with yield strength up to 355 MPa. On higher strength, lower ductility steels (C450 and above) emerging, CIDECT in 2009, extended the design guidelines to C450 RHS connections also, with certain restrictions on material, geometry and class of RHS. An overall reduction factor of 0.9 in design strength and a cap on σy at 0.8 σu were also stipulated. Experimental studies were conducted at the University of Sydney to verify the need and justification for the CIDECT restrictions in C450 RHS connections. This thesis complements the experimental studies using numerical methods and some novel techniques including use of an adapted Lemaitre damage model to track fracture, tracking necking in coupon tests by using recorded engineering stress-strain data and filling in gaps in data by methods such as use of FEA and/or crosshead data, grouping variations in material test results suitably and adopting a weighted average method to depict true stress strain that would reflect plastic deformation and damage. The FE models with these features were initially benchmarked against coupon test results, then validated against RHS jointless tests and finally against 12 K gap joint tests. More than 80 parametric variations that might influence the strength and behaviour of these joints were analysed using FEA. The study led to proposals for modifications to chord plastification, punching shear, chord side wall design equations to better predict ultimate loads and fracture modes. Reduced ductility in the steel was dealt with through a modifier function that is not based on yield stress but instead recognises the reduced ultimate strains, damage parameter for fracture and the ultimate stress of the material. Another research achievement is the perfection of a methodology to numerically predict the fracture / failure behavior of RHS joints and to formulate or test, design criteria if required.
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Cornelio, Diana. "Biologia reprodutiva e presença de cromossomo B em Astyanax scabripinnis (Teleostei: Characidae)." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2013. http://tede2.uepg.br/jspui/handle/prefix/975.
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Astyanax scabripinnis is a species found in the neotropics, this species forms demes isolated populations in headwater streams. It is taxonomically unresolved, but is presented as an interesting model to study the presence of chromosomal B. The occurrence of these chromosomes in A. scabripinnis may be associated with various environmental factors and population, although little savvy about maintaining parasitic or possible heterotic effects of these chromosomes. The reproductive biology related to the presence of B chromosomes in A. scabripinnis never been addressed. Thus, the object of this study was to investigate whether aspects of the reproductive process, fundamental to the adaptive value may be related to the presence of B chromosomes in A. scabripinnis. Samples were collected quarterly between the years 2012 and 2013 in Campos do Jordao, Sao Paulo, Brazil (22 ° 40 '49.5 "S, 45 ° 23` 31.9 "W) at Stream Farm Lavrinha basin of the Paraíba do Sul. The gonads were classified macroscopically and microscopically second stages of development. Settled seasonally sex ratio of the population in the different samples. We calculated the gonadosomatic ratio (GSR) and the relationship hepatossomática (RHS) separately for females with and without chromosome B. The presence of B chromosomes was confirmed by classical cytogenetic and molecular with the use of chromosome specific probe B constructed by chromosome microdissection and amplification Degenerated Oligonucleotids Primers (DOP-PCR) and subsequent in situ hybridization (FISH). Geometric morphometric analysis were performed separately for males and females with and without the presence of chromosomes B. The results indicate that the sex ratio varied seasonally having an increased number of males compared to females. Hermaphrodite individuals were found at a frequency of 7.7%. The reproductive period is characterized by an atypical reproductive peak during the winter period, beyond the period observed pattern from the spring in September. The presence of B chromosomes has been linked to possible reproductive strategies in different populations studied, especially in relation to energy intake and stages of gonadal development. There morphometric differences both between individuals female and male subjects with and without chromosome B.
Astyanax scabripinnis é uma espécie encontrada na Região Neotropical, essa espécie forma demes populacionais isolados em cabeceiras de riachos. Ela é taxonomicamente mal resolvida, mas se apresenta como interessante modelo para o estudo da presença de cromossomos B. A ocorrência desses cromossomos em A. scabripinnis pode estar associada a diversos fatores ambientais e populacionais, embora seja pouco esclarecido sobre a manutenção parasítica ou possíveis efeitos heteróticos desses cromossomos. A biologia reprodutiva relacionada à presença de cromossomo B em A. scabripinnis nunca foi abordada. Assim, foi objeto deste trabalho investigar se aspectos do processo reprodutivo, fundamental para o valor adaptativo, podem estar relacionados à presença de cromossomos B em A. scabripinnis. As coletas foram realizadas trimestralmente entre os anos de 2012 e 2013 na região de Campos do Jordão, São Paulo, Brasil (22°40`49,5”S, 45°23`31,9” W), no Córrego da Fazenda Lavrinha, bacia do rio Paraíba do Sul. As gônadas foram classificadas macro e microscopicamente segundo estádios de desenvolvimento. Estabeleceu-se sazonalmente a proporção sexual da população nas diferentes amostragens. Foi calculada a relação gonadossomática (RGS) e a relação hepatossomática (RHS) separadamente para fêmeas com e sem cromossomo B. A presença de cromossomos B foi confirmada por meio da citogenética clássica e molecular com o emprego de sonda específica do cromossomo B construída por microdissecção cromossômica e amplificação por Degenerated Oligonucleotids Primers (DOP-PCR) e posterior hibridação fluorescente in situ (FISH). Análises de morfometria geométrica foram realizadas separadamente para fêmeas e machos com e sem a presença de cromossomos B. Os resultados indicam que a proporção sexual variou sazonalmente havendo um aumento do número dos machos em relação às fêmeas. Foram encontrados indivíduos hermafroditas na frequência de 7,7%. O período reprodutivo é caracterizado por um pico de reprodução atípico no período do inverno, além do período padrão observado a partir da primavera no mês de setembro. A presença de cromossomos B foi relacionada a possíveis estratégias reprodutivas distintas na população estudada, especialmente em relação ao aporte energético e estádios de desenvolvimento gonadal. Há diferenças morfométrica tanto entre indivíduos fêmeas e machos como entre indivíduos com e sem cromossomo B.
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Quadros, Carlos Schmidt. "Rainwater harvesting case study: FCT/UNL campus." Master's thesis, Faculdade de Ciências e Tecnologia, 2010. http://hdl.handle.net/10362/4799.
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Dissertação apresentada para a obtenção do grau de Mestre em Engenharia do Ambiente, Perfil Engenharia SanitáriaWith increasing pressure on the environment, particularly on water resources, due to outside forces such as climate change and population growth, water is nowadays a scarce and a valuable resource. With the need to find new alternatives, rainwater harvesting should be seen as an important strategy for better management of water resources, once it constitutes a free source of potable water. Rainwater harvesting systems, which already have a global implementation, are a recognised way for urban buildings to reduce their reliance on the public mains supply. Its applications are predominantly non-potable, namely toilet flushing and gardening. The aim of this report is to produce a comprehensive assessment of rainwater harvesting and its potential use all over the world, as well as the potential economical and environmental benefits. It is provided a description of all the rainwater harvesting system components, as well as water quality requirements according to the water final purpose. A case study is presented, which main object is to evaluate the feasibility of rainwater harvesting for gardening, applied to the University Campus of the Faculty of Sciences and Technology of Universidade Nova, Lisbon (FCT/UNL). A detailed characterization of the existing irrigation system on campus is provided, as well as its potential ability to collect rainwater. According to the supply and demand balance, several scenarios are presented in order to provide the necessary information for the decision-makers to evaluate the best solution for the desired application. For such, all the available information was analyzed, in order to determine the environmental, technical and economical viability of the project.
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Pereira, Filipe José Botelho. "Juntas entre perfis tubulares de aço." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/11129.
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Dissertação para obtenção do Grau de Mestre em
Engenharia Civil - Estruturas e GeotecniaO presente trabalho tem como objetivo estudar o comportamento e resistência de juntas soldadas entre perfis tubulares de aço, bem como analisar e comparar as normas e recomendações referentes à sua análise e dimensionamento, em particular, a NP EN 1993-1-8 e as novas recomendações CIDECT. Em primeiro lugar, apresentam-se e discutem-se critérios, modos de rotura e modelos analíticos considerados na determinação da resistência deste tipo de juntas. De seguida, apresentam-se os critérios de dimensionamento prescritos pela NP EN 1993-1-8 e estabelece-se uma comparação com a formulação apresentada nas novas recomendações CIDECT. Por último, apresenta-se um caso de estudo, referente a uma viga em treliça integrada num sistema estrutural para suporte de um pavimento de betão armado. Efetua-se o dimensionamento das juntas com base nos dois documentos acima referidos e com o apoio do programa de cálculo CoP2 - V&M Edition, considerando juntas constituídas por perfis tubulares circulares (CHS) e por perfis tubulares retangulares (RHS).
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Ahamed, Mohamed Imran. "Fire performance and design of CFRP strengthened and insulated cold-formed steel tubular columns." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/127142/1/Mohamed%20Imran_Ahamed_Thesis.pdf.
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This research study investigated the fire performance of steel columns strengthened with Carbon Fibre Reinforced Polymers (CFRP). Using thermal and mechanical property tests, full scale fire tests and numerical analyses, it showed that suitable insulation layers can be successfully used to increase their fire resistance to required levels. It then developed new design guidelines to determine the fire resistance of CFRP strengthened and insulated steel columns.
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Seifert, Jason Paul Harden T. Kendall. "Regulation of phospholipase C-epsilon by Rho and Ras family proteins." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1008.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Dec. 18, 2007). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Pharmacology." Discipline: Pharmacology; Department/School: Medicine.
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Park, Ashley Yuuki. "Semi-rigid joints to tubular columns and their use in semi-continuous frame design." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/semirigid-joints-to-tubular-columns-and-their-use-in-semicontinuous-frame-design(5214b6d8-7df6-4197-bbcd-d4d92b8330df).html.
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Traditionally, joints are assumed to be either pinned or fully rigid, but in reality, many behave between these two extremes giving them a semi-rigid classification. By acknowledging the semi-rigidity of nominal pin joints, steel frames can be designed as semi-continuous in which the beam bending moments are partially transmitted to the column members and the need for lateral bracing is eliminated, thus reducing material and construction costs. This thesis presents the results of numerical and theoretical studies of the behaviour of bolted endplate connections to Rectangular Hollow Section (RHS) columns using flowdrill bolts and their applications in semi-continuous frame design. Such connections exhibit significant levels of initial stiffness, strength, and deformation capacity while being more cost-effective than fully welded connections. Despite this, there is limited theoretical work carried out that allows such connections to be designed using analytical methods. In addition, there are no standardised connection design tables like that for open section columns (SCI, 1995), thereby inhibiting their adoption in practice. In this thesis, newly derived equations for initial stiffness that have a greatly improved range of validity and accuracy over existing equations are presented. Equations for bending strength of a newly derived elliptical mechanism based on yield line theory and for membrane action based on internal work principles are given. Equations for flowdrill thread stripping due to gross deformation of the RHS face are also presented thus allowing prediction of all common RHS face failure mechanisms. Equations for deformation capacity are derived thus making it possible to predict the full load-deflection behaviour of the RHS face in tension component. When combined with existing equations for bolt and endplate components, it is possible to predict the full moment-rotation behaviour of bolted endplate connections to RHS columns. Extensive parametric studies using finite element analysis (FEA) as well as validation against existing tests show that the newly derived equations can accurately predict the component-level and whole joint behaviour for a wide range of configurations. Taking advantage of the initial stiffness properties that these connections offer, a parametric study is conducted to show that connections with relatively simple detailing can offer sufficient initial stiffness and strength to enable unbraced semi-continuous design of low-rise steel frames. A hand calculation method for SLS sway in semi-continuous frames is also presented thus allowing the designer to readily carry out scheme designs without advanced software knowledge. A systematic method for the detailing of these connections for use in unbraced frame design is presented to facilitate adoption in practice.
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Ducat, Aurélien Hervé. "Apports de l'étude in vitro et in vivo de la protéine STOX1 dans la compréhension des mécanismes physiopathologiques de la prééclampsie." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCB071/document.
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La prééclampsie est un syndrome pathologique défini chez la femme par l’apparition de novo d’une hypertension artérielle (pression artérielle systolique supérieure à 140 mmHg) et d’une protéinurie (supérieure à 300 mg par jour) au cours de la grossesse. Il s’agit de la deuxième cause de mortalité maternelle en France. Les mécanismes physiopathologiques de ce syndrome, encore mal connus, semblent faire intervenir une dysfonction placentaire à l’origine d’une activation systémique de l’endothélium maternel. Pour améliorer la prise en charge de la prééclampsie et prévenir les complications à court et à long terme, la clé serait d’associer la mise en place d’un dépistage précoce à de nouveaux traitements capables de renverser l’aggravation des symptômes qui, semblerait-il, est inévitable. Notre équipe travaille sur le gène STOX1, exprimé dans les cellules placentaires. Ce gène coderait un facteur de transcription dont jusqu’à présent aucun élément de réponse sur l’ADN n’a été trouvé. Des variants de ce gène ont été identifiés en 2005 chez des patientes atteintes de prééclampsie, et des études cellulaires ont montré que ce facteur est associé au syndrome prééclamptique. Deux modèles d’étude établis et caractérisés au laboratoire ont confirmé l’implication de ce gène dans le syndrome. Notre modèle cellulaire est une lignée de choriocarcinomes surexprimant STOX1. L’équipe a montré en 2008 que les altérations transcriptomiques dues à la surexpression de STOX1 dans cette lignée cellulaire sont corrélées à celles observées dans les placentas de patientes prééclamptiques. Notre modèle murin a été obtenu par transgénèse additive du gène STOX1 humain. Bien que la prééclampsie ne se développe pas spontanément chez les rongeurs, il a été montré en 2013 que des souris femelles sauvages croisées avec des mâles transgéniques développent un phénotype prééclamptique sévère comprenant une hypertension et une protéinurie. Dans le but de mieux comprendre le lien entre la surexpression de STOX1 et l’apparition d’une prééclampsie, nous avons exploré la production in vitro et in vivo de radicaux libres de l’oxygène et de l’azote, molécules constituant de bons candidats pour jouer un rôle pivot dans l’origine des symptômes. Nous avons pu montrer que STOX1 était capable, in vitro et in vivo, de moduler le stress oxydatif, la fonction mitochondriale et la balance des radicaux libres dérivés de l’oxygène et de l’azote. De plus, nous avons étudié dans le modèle murin l’effet de la surexpression de STOX1 dans le placenta sur les organes du système cardiovasculaires. Nous avons pu montrer que des souris femelles sauvages portant des foetus transgéniques subissaient une dysfonction endothéliale associée à une hypertrophie cardiaque pathologique. Enfin, des études en cours de biologie moléculaire in vitro et in silico tentent d’explorer plus finement les fonctions moléculaires et cellulaires de la protéine STOX1, afin de résoudre son rôle dans la prééclampsie, ou dans d’autres domaines de biologie cellulaire. Une partie de ces travaux a notamment permis d’identifier une séquence d’ADN physiquement reconnue par la protéine STOX1. Le travail réalisé au cours de cette thèse permettra d’une part de mieux comprendre la fonction d’une protéine impliquée dans des maladies complexes comme la prééclampsie et la maladie d’Alzheimer, et d’autre part d’aborder de façon plus ciblée la recherche de nouveaux marqueurs ou de nouvelles thérapeutiques pour la prééclampsie grâce au modèle murinPreeclampsia is a disease syndrome defined in women by the apparition of a de novo hypertension (systolic blood pressure above 140 mmHg) and proteinuria (greater than 300 mg per day) during pregnancy. This is the second cause of maternal mortality in France. The pathophysiology of this syndrome, still poorly understood, seem to involve placental dysfunction and a systemic activation of the maternal endothelium. To improve the management of preeclampsia and prevent short and long term complications, the key would be to combine the development of early screening and new treatments to reverse the worsening of symptoms which seem inevitable. Our team works on STOX1 gene, expressed in placental cells. This gene would encode a transcription factor for which no responsive element on the DNA has been found so far. Variants of this gene have been identified in 2005 among patients with preeclampsia, and cellular studies have shown that this factor is associated with preeclampsia syndrome. Two study models, established and characterized in the laboratory, confirmed the involvement of this gene in the syndrome. Our cell model is a line of choriocarcinoma overexpressing STOX1. The team showed in 2008 that the transcriptome alterations by STOX1 overexpression in this cell line are correlated with those observed in placentas of preeclamptic patients. Our murine model was obtained by additive transgenesis of the human STOX1 gene. Although preeclampsia does not develop spontaneously in rodents, it was shown in 2013 that wild type female mice mated with transgenic males develop a severe preeclamptic phenotype including hypertension and proteinuria. In order to better understand the link between the overexpression of STOX1 and the onset of preeclampsia, we explored the in vitro and in vivo production of oxygen- and nitrogen-derived free radicals, which are good candidates to play a pivotal role in causing symptoms. We showed that, in vitro and in vivo, STOX1 was able to modulate oxidative stress, mitochondrial function and free radicals balance. In addition, we studied in the mouse model the effect of an overexpression of STOX1 in the placenta on the cardiovascular system. We showed that wild female mice with transgenic fetus underwent an endothelial dysfunction associated with a pathological cardiac hypertrophy. Finally, molecular in vitro and in silico ongoing studies try to explore more precisely the molecular and cellular functions of STOX1 protein to resolve its role in preeclampsia, or in other areas of cell biology. Part of this work enabled the identification of a DNA sequence that is physically recognized by STOX1 protein. The work done during this thesis will help better understand the function of a protein involved in complex diseases such as preeclampsia and Alzheimer's disease. It will also help search for new markers or new treatments for preeclampsia thanks to the mouse model
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Lopes, Cristina Maria da Conceição Passos. "Estudo para a implementação de plataformas de e-learning no sistema de formação de recursos humanos da saúde: o caso particular dos enfermeiros de um hospital privado." Master's thesis, Universidade de Évora, 2011. http://hdl.handle.net/10174/14695.
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A chave para o sucesso de uma organização não está nas suas capacidades em gerir os bens tangíveis, mas antes em mobilizar e tirar partido dos seus bens intangíveis. Torna-se, assim, indispensável, numa sociedade que se caracteriza pela volatilidade da informação, na qual o ritmo de vida é cada vez mais acelerado e o conhecimento é um dos principais factores de competitividade, investir nas pessoas e no seu capital intelectual. Mas, para que isso se torne num valor acrescentado é preciso partilhá-lo através de REDES em ambientes cada vez mais colaborativos.
Os ambientes virtuais de aprendizagem no formato e-learning poderão constituir-se como soluções bastante interessantes capazes de incentivar essa partilha e fixar e desenvolver o capital intelectual de uma organização.
Nesta dissertação procura-se saber se existem condições organizacionais efectivas para a implementação de um modelo de blended learning utilizando uma plataforma de e-learning, que permita dar resposta às necessidades de formação contínua dos profissionais de saúde de um hospital privado. Para dar resposta a esta questão estuda-se o ambiente interno e externo no qual se insere.
Numa primeira fase, analisa-se as condições de partida dando ênfase à percepção da gestão de topo no que se refere à tomada de decisão: mudar o modelo de formação actual para um formato inovador de blended learning. Numa segunda fase, consolida-se a análise anterior observando outros indicadores e desenha-se o modelo propriamente dito.
É um estudo puramente exploratório, qualitativo, enquadrado num paradigma compreensivo - indutivo cujas evidências dão origem a um referencial de inovação na formação; ABSTRACT:The key to the success of an organization it’s not in their capabilities in managing tangible goods, but rather to mobilize and take advantage of its intangible assets. It is therefore essential in a society characterized by volatility of information, in which the pace of life is increasingly accelerated and knowledge is one of the main factors of competitiveness, to invest in people and in their intellectual capital. But for this to become an added value you must share it through networks in increasingly collaborative environments.
Virtual learning environments in e-learning format may be very interesting solutions capable of empower this sharing, to establish and develop an organization intellectual capital.
This thesis seeks to know whether there are actual organizational conditions for the implementation of a blended learning model using an e-learning platform, allowing the needs for continuing training of health professionals of a private hospital. To respond to this issue we study the internal and external environment in which it is inserted.
Initially, we examine the starting conditions giving emphasis to the perception of top management in decision-making: changing the current training model for an innovative format of blended learning. A second phase consolidates previous analysis observing other indicators and draws the model itself.
It is a purely exploratory study, qualitative, in which evidences are framed in a comprehensive - inductive paradigm, giving rise to a benchmark of innovation in training.
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Momkus, Audrius. "Lantano oksidinių junginių gamyba zolis – gelis metodu ir jų Rentgeno fotoelektronų spektrų tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120806_122447-54505.
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Darbo tikslas yra pagaminti La2O3 sluoksnius, atkaitinant prie aukštų temperatūrų nenaudojant vakuumo ir ištirti gautų sluoksnių Rentgeno fotoelektronų spektrus. Darbe aprašyti Rentgeno fotoelektronų spektroskopijos (RFS) (XPS - X-ray photoelectron spectroscopy) metodo, naudojamo įvairių medžiagų paviršių cheminei sudėčiai nustatyti, pagrindai. Pirmajame skyriuje aprašytas Rentgeno fotoelektroninės spektroskopijos metodas, pagrindinė RFS aparatūra bei teorinė dalis. Antrajame skyriuje aprašyti: La2O3 oksidiniai junginiai ir jų tyrimų metodika, plonų nanostruktūrizuotų medžiagų sluoksnių nusodinimo iš dujų fazės (plazmos) metodas- magnetroninis dulkinimas (magnetron sputtering), aparatūra ir zolis – gelis metodas. Trečiasis skyrius yra skirtas Rentgeno fotoelektroninių spektrų matavimų, naudojant spektrometrą XSAM 800 (Kratos Analytical, Didžioji Britanija) ypatumams ir bandinių gamybos metodikai aptarti. Pateiktas išsamus La2O3 sintezės zolių-gelių metodu technologijos aprašymas. Ketvirtajame skyriuje pateikiami eksperimentiniai rezultatai gauti, matuojant La2O3 Rentgeno fotoelektronų spektrus. Darbo pabaigoje yra pateikiamos išvados, kurios galėtų būti naudingos, tobulinant La2O3 bandinių gamybos technologiją. Gautas rezultatas: nustatyta, kad zolių – gelių technologija leidžia paprastais metodais, nenaudojant sudėtingos aparatūros,bei vakuuminės įrangos susintetinti La2O3.The aim of presented work was to synthesis by using sol-gel technology and investigate the X- ray photoelectron spectra (XPS) of La2O3 thin films in the annealed high temperature and without using vacuum installation. In the present work we described the essentials of the method of X-ray photoelectron spectroscopy, used to determine chemical composition of various materials. In the first part describes the X- ray photo-electronic spectroscopy method, basic XPS equipment and theoretical part. The second part are described: La2O3 oxide compounds and the methods of their production from the gas phase – magnetron sputtering and sol – gel method. In the third part we discussed the peculiarities and methodology of spectrometer XSAM 800 (Kratos Analytical, Great Britain) samples production while measuring X-ray photoelectron spectra. The thorough description of the technology by synthesis of La2O3 sol-gel method was provided. The fourth part presents the experimental results obtained by measuring the La2O3X-ray photoelectron spectra. In the end of the work conclusions are produced that could be useful in improving production technology of La2O3 samples. Obtained results: we identified that sol-gel technology allows synthesizing La2O3 by simple methods, without using sophisticated equipment and vacuum installation.
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Mahjoubi, Habib. "Nouvelle stratégie d'amélioration de la productivité végétale en condition de stress environnemental via un meilleur contrôle du cycle cellulaire." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ059/document.
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Le stress salin est l'un des principaux facteurs environnementaux limitant la croissance des plantes et entraînant des pertes de rendement des cultures céréalières. Il est ainsi impératif de développer des variétés plus tolérantes à la salinité afin d’augmenter leurs rendements et assurer la sécurité alimentaire. La voie signalétique reliant la perception du stress salin à la réponse cellulaire, encore peu connue, a été abordée ici par l’étude des protéines RSS1-like conservées chez les plantes. La protéine RSS1 (Rice Salt Sensitive 1) du riz joue un rôle primordial dans la tolérance au stress salin en agissant à l’interface entre la perception des stress et le contrôle du développement et de la division dans les méristèmes. Lors de ce travail, l'homologue de RSS1 nommé TdRL1 (Triticum durum RSS-Like 1) a été isolé à partir de la variété tunisienne de blé dur “Oum Rabiaa“. Nous avons démontré que TdRL1 porte les motifs D et DEN-Box conservés impliqués dans la régulation post-traductionnelle de la protéine. En outre nous avons apporté la preuve que TdRL1 est l’homologue fonctionnel de RSS1 puisqu'il est capable de complémenter le mutant de perte de fonction rss1, hypersensible au stress salin. En outre, l’expression hétérologue de TdRL1 améliore la tolérance au stress salin chez la levure ainsi que chez Arabidopsis et ce par l’augmentation du pouvoir germinatif et la réduction de l’accumulation des espèces oxygénées réactives. Nos études cytologiques ont montré que la protéine TdRL1 est cytoplasmique en interphase et se localise au niveau des microtubules kinétochoriens pendant la mitose. Remarquablement, TdRL1 change de localisation cellulaire sous stress salin et montre une accumulation partielle dans le noyau, soulignant le caractère multifonctionnel de cette protéine dans la réponse au stress salin. L’ensemble des données suggère que sous contrainte saline, TdRL1 joue un rôle dans la régulation du cycle cellulaire en relation avec le réseau microtubulaire. L‘étude de la famille RSS1-like multifonctionnelle permettra ainsi d’aborder de nouvelles voies de recherche pour la création variétale de blé plus résilientes aux stress de l'environnementSalt stress is one of the main environmental factors limiting plant growth and yield in cereal crops. It is therefore imperative to develop varieties more tolerant to salt stress in order to increase yield and ensure food security. The signaling pathway linking salt stress perception to cellular response was addressed here by studying RSS1-like proteins in plants. RSS1 (Rice Salt Sensitive 1) protein plays an important role in salt stress tolerance. It acts at the interface of stress perception and developmental control and division in meristems. During this work, the RSS1 counterpart named TdRL1 (Triticum durum RSS-Like 1) was isolated from the durum wheat Tunisian variety "Oum Rabiaa". We have demonstrated that TdRL1 carries the conserved D and DEN-Box motifs involved in the post-translational regulation of the protein. In addition, we show that TdRL1 is the functional homologue of RSS1 since it was able to complement the loss-of-function mutant rss1, hypersensitive to salt stress. In addition, heterologous expression of TdRL1 enhances salt stress tolerance in yeast and in Arabidopsis by increasing germination and reducing the accumulation of reactive oxygen species. Our cytological studies have shown that the TdRL1 protein is cytoplasmic in interphase and is localized at the spindle during mitosis. Remarkably, TdRL1 changes its subcellular localization under salt stress treatment and shows a partial accumulation in the nucleus, highlighting the multifunctional nature of this protein during salt stress response. Our data suggest that under salt stress, TdRL1 plays a role in the regulation of the cell cycle in relation with the microtubule network. Pursuing the study of RSS1-like multifunctional proteins will open up new research areas for the creation of wheat varieties that are more resilient to environmental stresses
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Gonçalves, Ana Rosária Oliveira. "Procedimentos de licenciamento de utilizações de água nas regiões hidrográficas do Sado e Mira (RH6) e do Guadiana (RH7)." Master's thesis, Universidade de Évora, 2012. http://hdl.handle.net/10174/18244.
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Actualmente a água é um valor patrimonial ecológico e social que satisfaz funções em detrimento do seu uso. Face a este modelo, é necessário efetuar uma gestão integrada de recursos naturais, onde a água desempenha um papel decisivo. O presente quadro legal e institucional português, assente na Directiva Quadro da Água, aponta claramente para uma visão de protecção e utilização sustentável das massas de águas subterrâneas e de superfície, quer sejam interiores, estuarinas ou costeiras. Nesta perspectiva, visando a melhoria contínua dos serviços prestados, apostando na modernização e simplificação administrativa para uma utilização eficiente e sustentável das águas, procede-se à organização metódica, coerente e integrada dos procedimentos de licenciamento no âmbito da utilização dos recursos hídricos para captação de águas existentes nas regiões hidrográficas do Sado e Mira (RH6) e do Guadiana (RH7), afectas à Administração da Região Hidrográfica do Alentejo, I.P. Esta estrutura de procedimentos sistematiza os trâmites associados aos procedimentos legais e técnicos, desde a formalização da instrução de pedido, à decisão e consequente emissão de título. Adoptando uma perspectiva de consistência na tramitação dos processos de licenciamento, pretende-se formalizar nesta metodologia, uma ferramenta, para utilizadores e técnicos superiores da administração pública, que possibilite maior celeridade e eficácia na apreciação processual, bem como minimizar constrangimentos ao desenvolvimento das actividades associadas e/ou dependentes de captações de água; ABSTRACT: Nowadays water is an ecological and social heritage with functions determined by its use. This model requires natural resources integrated management, where freshwater plays a decisive role. The portuguese present institutional and legislative framework, regulations that transpose the Water Framework Directive, lead to protection and sustainable use of inland surface waters, transitional waters, coastal waters and groundwater. Hence, in order to improve official services for a simpler and more modern administration, aiming efficient and sustainable use of water, this procedures establishes a coherent and methodical organization of water use permit procedures for Sado and Mira (RH6) and Guadiana (RH7) river basin districts, in the Administração de Região Hidrográfica do Alentejo, I.P. area. This methodology gathers water permit legal and technical procedures, from the request to permit issuance. This guide to both water users and permit writers will ensure consistency in procedures in order to create a faster and effective review instrument and minimize water abstraction dependent activities constraints.
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Holsenbeck, Stephanie Leah. "H-RAS AND ITS ONCOGENIC MUTANTS RAS G12V AND RAS Q61L." NCSU, 2006. http://www.lib.ncsu.edu/theses/available/etd-04062006-162655/.
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The H-Ras protein is a GTPase important to cell cycle and differentiation. Mutations in this protein have been associated with 30% of cancers. A better understanding of this protein could lead to innovative treatments of cancers caused by the mutations. Solvent mapping of the crystallized Q61L mutant of the H-Ras protein with glycerol shows with potential areas of protein/protein interactions, areas that are of particular interest in the design of anti-cancer drugs. This study investigated whether glycerol can distinguish changes in the surface due to the mutation. A comparison was made between the wild-type and Q61L mutant H-Ras crystal structures in glycerol and aqueous solution. The structural analysis lead to the conclusion that the main changes observed were due to the solvent environment and not to the mutation.
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Tao, Yunxiang. "Advanced numerical analysis and fire testing of cold-formed steel hollow section stud walls." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/226716/1/Yunxiang_Tao_Thesis.pdf.
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This research investigated the behaviour of light gauge steel frame walls made of cold-formed steel hollow section studs under both ambient and fire conditions using full scale experimental and advanced numerical studies. It developed and improved new structural and fire design rules for hollow section stud walls that can be included in the Australian steel structures standard. Importantly, it showed that such wall systems have superior fire resistance than conventional wall systems used currently. Overall, this research has sufficiently improved the knowledge of light steel walls made of hollow section studs in fire, enabling structurally efficient and safer designs.
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Volk, Catherine B. "Role of inhibition of protein prenylation in the cholesterol-dependent and cholesterol-independent effects of simvastatin." Virtual Press, 2006. http://liblink.bsu.edu/uhtbin/catkey/1339597.
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Statins are widely used to treat hypercholesterolemia. Statins inhibit cholesterol biosynthesis, thereby activating genes involved in cholesterol homeostasis, which are under the control of the Sterol Regulatory Element (SRE). Statins also have cholesterol-independent beneficial cardiovascular effects mediated through the phosphoinositide 3-kinase (PI3-K) / Akt signaling pathway and by inhibition of protein prenylation. Because statins inhibit the synthesis of isoprenoids, they can act by inhibiting the small signaling GTPases Ras and Rho, which require post-translational prenylation to become membrane-anchored and functional. We showed that simvastatin-mediated inhibition of protein prenylation does not appear to play a role in activation of SRE transcriptional activity in HepG2 cells. We also found that when isoprenoids were replenished, basal phospho-Akt decreased, suggesting that inhibition of prenylation by simvastatin mediates Akt phosphorylation. Future studies will be needed to investigate the role that inhibition of protein prenylation plays in the activation of the PI3-K/Akt pathway by simvastatin.Department of Biology
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Hawisa, Samia Tayeb. "Investigation into the functional differences between N-ras, H-ras and K-ras." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312822.
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Gunaretnam, Erandika Prasadani. "Identification of M-RAS/RAS-2 expression patterns in Caenorhabditis elegans and characterization of M-RAS/RAS-2-null worms." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/47019.
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M-Ras is a member of the Ras superfamily of small-molecular weight-GTP binding proteins. It is a close relative of the oncoprotein p21Ras and shares 50% overall amino acid sequence identity. ras-2 is the Caenorhabditis elegans ortholog of the human M-Ras. It shows strong conservation of structure in worms and vertebrates. In mammals, endogenous M-Ras acts downstream of the EGF and FGF receptors to activate ERK (MAPK) signaling. The M-Ras is predominantly expressed in the mammalian central nervous system and the heart. Many human cancers including breast and colonic cancers exhibit dramatic elevations of M-Ras mRNA.
Receptor tyrosine kinase /RasGTPase/ERK signaling pathway is evolutionary conserved. In C. elegans this highly conserved signaling pathway controls many biological processes including vulval induction. C. elegans is a good model system to understand the role of M-Ras in RTK/Ras/ERK pathway.
To understand the expression patterns of RAS-2 in C. elegans, I generated a transgenic C. elegans that expresses GFP driven by the endogenous ras-2 promoter. To investigate the effect of over expressed or activated RAS-2, I also generated transgenic lines over expressing WT or activated RAS-2. I observed that RAS-2 is expressed in various tissues and organs of C. elegans including amphid sensory apparatus, proximal myoepithelial sheaths, spermatheca and in developing gonads. Based on the ras-2 expression patterns, I chose and performed appropriate behavioral assays to characterize ras-2 null worms. The phenotypic characterization and behavioral observations on ras-2 null worms revealed several phenotypes including smaller body size and faster locomotion. Furthermore, based on the behavioral assays, I found that ras-2 mutants have a normal ability to sense inputs and reproduce.
To investigate the importance of RAS-2 in pathological signaling of activated LET-23 (EGFR) or activated LET-60 (p21Ras) which cause multivulval phenotype in C. elegans, I examined the different vulval phenotypes in crosses between ras-2 null worms and let-23 or let-60 activated mutants. This revealed that ras-2 null background do not suppresses multivulval phenotype caused by activated let-23 or let-60. However, the activated let-60 exhibits a higher frequency of protruding vulva in the absence of ras-2.
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De, Hoog Carmen Lenore. "Regulation of the Ras exchange factor Ras-GRF2." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63718.pdf.
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Montaletti, Luca. "Spectral index of radio halos and X-ray temperatures." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17926/.
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Osservazioni X e Radio di ammassi di galassie dimostrano che nel mezzo intracluster coesistono componenti termiche e non termiche. Mentre le osservazioni X rivelano l'emissione termica da gas caldo diffuso, le osservazioni radio di un numero crescente di galaxy cluster massivi, hanno svelato la presenza di particelle ultrarelativistiche e campi magnetici, attraverso il rilevamento di emissione radio diffusa di sincrotrone: radio halos (RHs) e relitti. I RHs sono sorgenti radio giganti (~1Mpc) localizzate nelle regioni centrali dell’ammasso, con estensione spaziale simile a quella dell’hot ICM. In letteratura ci sono evidenze collettive che i RHs si trovano in ammassi sottoposti a fenomeni di Merger, questa connessione suggerisce che i processi gravitazionali di formazione degli ammassi potrebbero fornire l’energia per generare le componenti non termiche nei cluster. In questa tesi, per testare quantitativamente la connessione RH-merger, sono state svolte analisi statistiche basate su osservazioni radio e X, in particolare è stata indagata una correlazione, proposta nel 1999 da Colafrancesco, fra la temperatura kTX e P1.4GHz, ma non è stata trovata nessuna correlazione significativa kTX-P1.4GHz in un campione di 60 ammassi. Ulteriori indagini sono quindi state svolte sugli indici spettrali α dei RHs, che meglio di P1.4GHz sono evidenza di accelerazione elettronica (e/o compressione di campo magnetico): le analisi sono state condotte su 54 valori di α. Oltre alle analisi statistiche è stato svolto un approfondimento sul calcolo dell’indice spettrale di A1914, per quale è stato osservato uno steepening dello spettro a 98 MHz: α(<98MHz)=1.41 e α(>98MHz)=2.09. Riportiamo inoltre uno studio osservativo a 1.5GHz (dati JVLA) per gli ammassi MACS J0417, con RH noto in letteratura per il quale è stato calcolato un valore di indice spettrale α=0.98, e MACS J0647, che presenta 2 sorgenti radio con proprietà morfologiche tali da essere candidate come alone e relitto.
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Tancred, Linda. "Mechanisms of the intracellular survival of Francisella tularensis." Doctoral thesis, Umeå universitet, Klinisk bakteriologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-45869.
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Francisella tularensis is a gram-negative, highly virulent, intracellular bacterium which causes the zoonotic disease tularemia. The subspecies tularensis and holarctica are clinically important, and the former is the more virulent. The intracellular lifestyle of F. tularensis is not completely understood, but after uptake in monocytes, the bacterium escapes from the phagosome within hours and replicates massively in the cytosol. The escape is dependent on factors encoded by the Intracellular Growth Locus (igl) operon, located in the Francisella Pathogenicity Island, FPI. The thesis was aimed to clarify and understand the interaction of F. tularensis strains with the endosomal pathway of monocytic cells in general and the roles of the Igl proteins and the global regulator MglA for this interaction in particular. A focus has also been to elucidate the roles of reactive oxygen and nitrogen species for the intracellular host-parasite interaction. We show that mutants in the IglB, IglC, or IglD proteins or their regulator MglA of the live vaccine strain, LVS (subspecies holarctica), all demonstrated reduced replication rates and lowered cytopathogenicity compared to the wild type in a J774 mouse macrophage cell model. Colocalization with LAMP-1 was significantly increased for the IglC, IglD and MglA mutants compared to LVS. This indicated an impaired ability to escape into the cytoplasm, while at the same time they, like LVS, partly prevented fusion with lysosomes. IFN-γ activation of the J774 host cells prior to infection had a bactericidal effect on LVS and all of the mutants, though the cidal effect was significantly more pronounced for the mutants. Following IFN-γ activation, a majority of the mutant-containing phagosomesfused with lysosomeswhile LVS remained localized in the cytosol without significantly increased interactions with the endosomal pathway. Previous studies have revealed that IFN-γ activation of F. tularensis-infected macrophages leads to control of infection but conclusions about the importance of reactive nitrogen and oxygen species on bacterial killing are inconsistent. We found that the growth inhibition resulting from IFN-γ activation could not be attributed to an increased oxidative burst since PMA-induced superoxide production was still inhibited by LVS to the same extent as in non-activated macrophages. On the other hand, reactive nitrogen species may in part have contributed to the cidal effect. To further assess the role of reactive nitrogen species to the killing of F. tularensis, nitric oxide was administrated exogenously to J774 cells infected with LVS. This led to significant killing of intracellular LVS with a concomitant increased phagosomal localization and downregulation of the virulence gene regulator mglA. These effects were reversed by addition of a peroxynitrite decomposition catalyst. A spontaneous avirulent mutant of subspecies tularensis, strain FSC043, was previously demonstrated to provide protective immunity in mice. Here, microscopic analyses of the strain revealed an unusual intracellular localization with a delayed phagosomal escape. This may account for the low virulence, while at the same time FSC043 remains immunogenic and thereby confers protection. The igl operon is intact in strain FCS043 and we hypothesize that a defect in the FPI gene pdpC contributed to the observed phenotype. Altogether, this thesis work demonstrates the importance of the mglA and igl genes for the virulence of F. tularensis and specifically their important roles for a functional phagosomal escape and inhibition of the host cell oxidative burst. Also, addition of exogenous nitric oxide likely leads to formation of peroxynitrite intracellularly, a reactive molecule which confines the bacterium to the phagosome and confers a significant bactericidal effect on intracellular F. tularensis.
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Rodrigues, Artemis Socorro do Nascimento. "Caracterização molecular dos antigenos RhD, (RhD fraco e RhD parcial) e sua aplicação na pratica transfusional." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/310418.
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Orientador: Lilian Maria de CastilhoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: Considerando a imunogenicidade e importância clínica do antígeno RhD bem como o grande número de variantes RhD identificadas, estudos que possam esclarecer sua expressão e mecanismos moleculares envolvidos são importantes para a padronização de técnicas moleculares e sorológicas em diferentes populações. Assim foram nossos objetivos: padronizar técnicas moleculares para realização da genotipagem RHD fraco e determinar sua ocorrência na população brasileira; associar os tipos de RhD fracos encontrados com os haplótipos Rh presentes; e avaliar a aplicação da determinação do antígeno RhD na prática transfusional. Estudamos 503 amostras de DNA de doadores voluntários de sangue fenotipados como RhD ftaco. Destas amostras de DNA estudadas, 415 (82,5%) foram caracterizadas como RhD ftaco, 65 (12,9%) como RhD parcial, 15 (3%) apresentaram associações de RhD parcial e RhD ftaco e 8 (1,6%) foram RhD normal. I Os antígenos RhD fraco tipos 1, 3 e 4 foram os mais fteqüentes em nossa população. Como estes três tipos de RhD fraco não apresentam risco de aloimunização anti-D, pacientes assim classificadospodem ser transfundidos com sangue RhD-positivo. Nossos resultados demonstraram que 12,~A>das amostras fenotipadas como RhD fraco eram na verdade RhD parcial. Os antígenos RhD parciais encontrados em nosso estudo foram D~ DHMi e DVI. Quarenta (7,9%) amostras de DNA foram caracterizadas como D~ 16 (3,2%) como DHMi e 9 (1,8%) como DVI. A caracterização dos antígenos RhD parciais que reagem sorologicamente como RhD ftaco, tais como D DHMi e RhD categoria VI pode ser de grande auxilio na prevenção da aloimunização anti-D em pacientes politransfundidos e gestantes. A freqüência dos antígenos RhD parciais D~ DHMi e DVI encontrada em nossas amostras sugere um elevado risco de aloimunização ao antígeno RhD em pacientes fenotipados como RhD ftaco. - Das 503 amostras estudadas, 15 apresentaram mutações responsáveis pela expressão do antígeno RhD fraco e ao mesmo tempo mutações características de antígenos RhD parciais, ou seja, estas amostras possuíam os antígenos RhD fraco e RhD parcial associados. Estudamos quatro amostras de DNA de pacientes fenotipados como RhD :fraco que apresentavam anti-D. Nosso estudo demonstrou que a aloimunização anti-D nestes pacientes estava relacionada à presença de um antígeno RhD parcial e não a um antígeno RhD :fraco como diagnosticado sorologicamente. Duas amostras foram classificadascomo RhD parcial DAR, 1 como RhD parcial DHMi e 1 como DVI. Os resuhados demonstraram que os tipos de RhD fraco 1, 2, 3 e 4 que foram detectados à TA ou à 3'te e apresentaram grau de aglutinação superior a 1+ na AGH podem ser considerados como RhD positivo, pois não foram associados ao antígeno RhD parcial. Apesar deste trabalho ter sido o único que relacionou os tipos de RhD ftaco com o grau de aglutinação, a literatura revela que ainda não foi demonstrada aloimunização anti-D em pacientes portadores dos antígenos RhD fraco tipos 1,2 e 3. De acordo com os nossos resultados pode-se concluir que: 1. A transfusão com sangue RhD-positivo pode ser recomendada para todos os pacientes que apresentam os tipos do antígeno RhD :ftaco 1, 3 e 4 identificados por técnicas moleculares e para aqueles que apresentarem grau de aglutinação superior a 1+ na fenotipagem RhD. 2. A utilização de métodos de fenotipagem mais sensíveis em combinação com reagentes anti-D de alta afinidade é recomendada na detecção de antígenos RhD ftaco com baixa densidade antigênica em doadores de sangue; 3. Há necessidade da utilização de dois anti-soros monoc1onais (IgM e IgG) na determinação do antígeno RhD :ftacoem pacientes; 4. As genotipagens RHD, RHD ftaco e RHD parcial devem ser rea1i73dasquando os resuhados sorológicos não forem claros ou quando o paciente for politransfundido. 5. A biologia molecular associada à hemaglutinação pode aumentar consideravelmente a segurança transfusional pela mellior caracterização dos antígenos RhD em nossa população
Abstract: The purpose of this study was to characterize by molecular studies theRhD antigens (weak D and partial D) in Brazilian blood donors. DNA samples ftom 503 blood donors phenotyped as weak D were tested by two different sequence-specific primers (pCR-SSP) assays to determine the presence or absence of RHD gene (PCR-SSP intron 4 and exon 10) and to detect the common weak D types. Ofthe 503 weak D samples studied, 415 (82,5%) were identified as weak D, 65 (12,9%) as partial D, 15 (3%) showed association ofweak D and partial D and 8 (1,6%) were normal D. Weak D types 1, 3 and 4 contributed more than 85% of alI molecular weak D types. For these 3 types, D-positive transfusion can be considered safe because no immunization events have been documented yet. These findings show for the first time the frequency of weak D types in Brazilians. Molecular analysis showed that 12,9% of the weak D phenotype samples studied carried a partia! D alIele. The partial Ds found in our study were DAR, DVI and DHMi. Forty (7,9%) DNA samples were characterized as DAR, 16 (3,8%) as DHMi and 9 (1,8%) as DVI. The characterization of the partia! D antigens DAR, DHMi and DVI may avoid alIoimmunization in patients phenotyped as weak D. Fiffeteen patients showed mutations to weak D and partia! D showing that these samples had the weak D and partia! D antigens associated. We also studied 4 DNA samples of patients phenotyped as weak D who had developed anti-D. Our study showed that anti-D alIoimmunization in these patients was associated with the presence of partia! D antigens. Two samples were classified as partia!, D DAR, 1 as DHMi and 1 was DVI.AlI the weak D types identified in our study were associated with the intensity of agglutination obtained at room temperature (RT), 3'fC and AGH. The sensitivity of detecting weak D depends on the anti-D reagent and on the exact conditions of the methods. Our results showed that the weak D types 1, 2, 3 and 4 were frequently detected at RT and 3'fC and therefore could be considered as D-positive for transfusion. According to our results we could recommend the use ofmonoclonal anti-DIgM with high avidity to detect weak D antigen with low antigen density in blood donors and two monoclonals, one IgM and one IgG in combination with AGT to detect the weak D antigen in patients
Doutorado
Ciencias Basicas
Doutor em Clínica Médica
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Coudray, Laëtitia. "Synthèse d'inhibiteurs de la protéine farnésyltransférase de type bisubstrat." Paris 11, 2005. http://www.theses.fr/2005PA114832.
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La protéine farnésyltransférase (FTase) est une nouvelle cible thérapeutique dans le domaine du cancer, des maladies parasitaires et virales. Cette enzyme catalyse le transfert d'un groupement farnésyle à partir du pyrophosphate de farnésyle (FPP) sur une cystéine en position C-terminale de protéines impliquées dans la transduction du signal de division et de survie cellulaire. De nombreux inhibiteurs compétitifs de chacun des deux substrats ont été rapportés mais seulement quelques composés de type bisubstrat sont décrits. Ainsi, l'étude de composés de ce type mimant l'état de transition est apparue importante et a fait l'objet de cette thèse. Une première partie porte sur la synthèse et l'évaluation biologique de composés conçus pour mimer l'état de transition de la FTase. Ces structures comprennent trois éléments : un groupement prényle, un motif b-diacide et un noyau imidazole. Une seconde partie traite de l'étude d'analogues du FPP à fonction acide modifiéeThe enzyme protein farnesyltransferase (FTase) is a new target in anticancer therapy and also in viral and parasitic fields. FTase transfers the farnesyl group from farnesyl pyrophosphate (FPP) to the C-terminal cysteine of proteins involved in signal transduction. Lot of competitive inhibitors of FTase have been described but only few examples of bisubstrate inhibitors have been reported. Therefore, the study of this kind of compounds able to mimic the transition state of FTase seemed to be important and it was the subject of this thesis. The first part deals with the synthesis and the biological evaluation of compounds designed to mimic the transition state of FTase. These structures are composed of three elements : an isoprenyl moiety, a diacid group and an imidazole ring. The second part describes the study of FPP analogs with a modified acidic function
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Farias, Filho Antonio Lima. "Utilização de reatores aeróbios como pós-tratamento de lixiviado antigo tratado por lagoas de estabilização." reponame:Repositório Institucional da UFC, 2010. http://www.repositorio.ufc.br/handle/riufc/16350.
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FARIAS FILHO, A. L. Utilização de reatores aeróbios como pós-tratamento de lixiviado antigo tratado por lagoas de estabilização. 2010. 84 f. Dissertação (Mestrado em Engenharia Civil: Saneamento Ambiental) – Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2010.Submitted by João silva (jpauloqxb@gmail.com) on 2016-04-22T13:55:44Z No. of bitstreams: 1 2010_dis_alfariasfilho.pdf: 1242877 bytes, checksum: 070051f4c3080bfb2c9c020a546f6e6f (MD5)
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The system of stabilization ponds, which is often present in landfills, is usually not efficient to meet environmental standards for disposal of treated leachate on surface waters. This study evaluated the use of submerged aerated reactor (SAR) and sequencing batch reactor (SBR) as post-treatment options for old leachate pre-treated in waste stabilization ponds. The leachate collection took place at the outflow of the last stabilization pond of the treatment system (two anaerobic em series, followed by a facultative pond) located in West Metropolitan Landfill (ASMOC), Caucaia municipality, metropolitan region of Fortaleza, Ceará state. A physical-chemical characterization of the leachate effluent was performed to verify the compliance to reach disposal standards. The SAR was operated in five phases, being divided between synthetic wastewater and leachate, the latter tested with and without dilution. We evaluated the effect of adding an external carbon source, ethanol, for the phase in which the reactor was fed with leachate without dilution. SBR was made of acrylic, in a cylindrical shape with a working volume of 5.0 L and the total time cycle of 24 hours was initially studied. The total time cycles of 12 and 48 hours were also evaluated in the SBR performance, as well as the effect of adding ethanol as carbon source. The reactors were installed at the Laboratory of Sanitation (Labosan) of the Department of Hydraulic and Environmental Engineering (DEHA), Federal University of Ceará (UFC). They were operated in the mesophilic range, with temperature near 27 ° C. Regarding the treated leachate, the physical-chemical characterization confirmed its recalcitrance and complexity, indicating that only the stabilization ponds did not fully meet the standards of disposal. The presence of recalcitrant and toxic compounds in the leachate influent to the SAR during the investigation period decreased COD removal, showing an inhibitory effect on the microorganisms present in the inoculum. However, in another research phase, both the SAR and SBR were stable and efficient on COD and ammonia removals, even when undiluted leachate was used. The addition of ethanol as external carbon source was beneficial to meet the microbial metabolic needs, increasing both the overall efficiency of SAR and SBR in terms of organic matter removal (COD) and operational stability. The SAR and SBR were also quite efficient in the nitrification process. The study with SBR with cycle times of 12, 24 and 48 h showed no considerable difference amongst the constituent removals, so that 12 h was considered as optimal time cycle in order to minimize the costs with reactor volume and aeration time. As a general conclusion of the experiment we can say that the aerobic biological treatment, using either submerged aerated reactor (SAR) or sequencing batch reactors (SBR), can be considered a good alternative for post-treatment of old leachate pre-treated in stabilization ponds, but still requires operational adjustments and associations with physical-chemical or advanced oxidation processes for accomplish all discharge standards.
Os sistemas de lagoas de estabilização, bastante presentes em aterros sanitários normalmente não são suficientes para o atendimento aos padrões ambientais de descarte de lixiviado tratado em águas superficiais. Este trabalho avaliou o emprego das tecnologias aeróbias do tipo reator aerado submerso (RAS) e reator em batelada seqüencial (RBS) como opções de pós-tratamento para lixiviado antigo pré-tratado em lagoas de estabilização. A coleta do lixiviado se deu na saída da última lagoa de estabilização do sistema de tratamento de lixiviado (duas anaeróbias em série, seguidas de uma facultativa) localizadas no Aterro Sanitário Metropolitano Oeste (ASMOC), município de Caucaia, Região Metropolitana de Fortaleza, estado do Ceará. Inicialmente foi realizada uma caracterização físico-química do lixiviado efluente e verificação do atendimento aos padrões de descarte. O RAS foi operado em cinco fases, sendo divididas entre esgoto sintético e lixiviado, este último testado com e sem diluição. Avaliou-se o efeito da adição de fonte externa de carbono, etanol, para a fase em que o reator era alimentado com lixiviado sem diluição. O RBS foi confeccionado em acrílico, em formato cilíndrico, com um volume útil de 5,0L, sendo inicialmente estudado o tempo de operação de cada ciclo de 24 horas. Posteriormente, foram avaliados no RBS os tempos totais de ciclo de 12 e 48 horas, além do efeito da adição de etanol no desempenho do reator. Os reatores foram instalados no Laboratório de Saneamento (Labosan) do Departamento de Engenharia Hidráulica e Ambiental (DEHA) da Universidade Federal do Ceará (UFC). Eles foram operados na faixa mesofílica, com temperatura ambiente próxima de 27ºC. Em relação ao lixiviado tratado, os valores encontrados na caracterização físico-química confirmam a recalcitrância e complexidade do lixiviado, indicando que apenas as lagoas de estabilização, não atendem plenamente os padrões de descarte. A presença de compostos recalcitrantes e tóxicos no lixiviado afluente ao RAS durante um dos períodos de investigação causou diminuição na remoção de DQO, mostrando efeito inibitório nos microrganismos presentes no inóculo. Entretanto, em outra fase de investigação, tanto o RAS quanto o RBS se mostraram eficientes e estáveis na remoção de DQO e nitrogênio amoniacal, mesmo tratando lixiviado sem diluição. A adição de etanol como fonte externa de carbono foi benéfica para suprir as necessidades metabólicas microbianas, fazendo aumentar tanto a eficiência global do RAS e RBS em termos de remoção de matéria orgânica (DQO), assim como na estabilidade operacional dos mesmos. O RAS e o RBS foram também bastante eficientes no processo de nitrificação. O estudo no RBS com os tempos de ciclo de 12, 24 e 48 h revelaram que não houve diferença entre os tempos em relação à remoção dos constituintes analisados, fazendo com que se considerasse 12 h como tempo ótimo de ciclo, de forma a minimizar os custos com volume do reator e tempo de aeração. Como conclusão geral do experimento pode-se dizer que o tratamento biológico aeróbio, tanto utilizando reatores aerados submerso (RAS) quanto reatores em batelada seqüencial (RBS), pode ser considerado uma boa alternativa para o pós-tratamento de lixiviado antigos provenientes de sistemas de lagoas de estabilização, mas ainda requer adequações operacionais ou associações com processos físico-químicos ou de oxidação avançados para o enquadramento de todos os constituintes.
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Schwarz, Daniel. "Funktionelle und strukturelle Charakterisierung von Ras-Effektoren Eigenschaften des kleinen Ras-Effektors Novel Ras Effector 1 (Nore1) /." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=967348013.
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Love, Julie Ann. "Structural and functional analyses of H-Ras and R-Ras." Thesis, University of Edinburgh, 2005. http://hdl.handle.net/1842/24854.
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In this thesis I have sought to gain further insight into the regulation of integrin affinity and cellular function by Ras GTPases. A series of H- and R-Ras chimeras have been used to examine the hypothesis that specific sequences within these molecules govern their differential effects on integrin function and cellular transformation. Understanding the structure/function relationship between H-Ras and R-Ras may help to elucidate their downstream effectors which regulate integrin function and define the relevance of MAP kinase activation with regards to integrin activation and cellular transformation. This may lead to a better understanding of the development of cancer. Expression of the H- and R-Ras chimeras within an integrin reporter system (αβ-py cells) revealed that a C-terminal 25-amino acid stretch of H-Ras was required for full suppressive activity, and that the equivalent C-terminal 28-amino acid stretch of R-Ras was required to fully reverse H-Ras/Raf-intiated integrin suppression. The effects of these amino acids stretches on integrin function was further confirmed by investigations into the changes in cytoskeletal organisation and overall cellular morphology. Furthermore, the data suggest that the effects on integrin function are independent of the activation of the ERK1/2 MAP kinase pathway. This implicates a novel mechanism whereby Ras modulates integrin affinity. In summary, it is shown that H-Ras- and R-Ras-mediated integrin is regulated by distinct C-terminal domains. Moreover, integrin affinity modulation is independent of ERK1/2 MAP kinase activation. In addition there is an apparent correlation between suppression of integrin function and cellular transformation.
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Axelsson, Lena. "Karakterisering av blodgruppsgenen RHD hos patienter med svagt RhD-antigenuttryck." Thesis, Malmö högskola, Fakulteten för hälsa och samhälle (HS), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-24168.
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Rh-blodgruppssystemet är mycket komplext med 54 blodgruppsantigen som kodas av två nära varandra belägna gener på kromosom 1 – RHD och RHCE. RHD-genen kodar för RhD-proteinet, ett membranbundet protein på erytrocyter vars antigen utgör de kliniskt viktigaste och mest immunogena efter ABOsystemets, och som kan ge upphov till transfusionskomplikationer och hemolytisk sjukdom hos foster och nyfödda. Vissa individer har varianter av RhD-protein som uttrycks svagare än normalt (”svaga D”), eller där vissa epitoper saknas (”partiella D”), och för vilka serologiska metoder inte kan ge enhetliga resultat. Detta orsakar problem vid blodtransfusion, graviditet och bloddonation, och leder ofta till användning av det redan knappa lagret av RhD-negativa blodenheter för att skydda patienten. I detta projekt har åtta prover med svaga RhD-antigenuttryck sekvenserats med avseende på RHD-genen i syfte att fastställa individernas RhDfenotyp. I sex av proverna hittades sex nukleotidpolymorfismer och två deletioner, som alla är sällsynta men dock är kända sedan tidigare. I två prover kunde inga mutationer i exon eller intilliggande intron påvisas som förklaring till de svaga uttrycken av RhD hos dessa individer.The Rh blood group system is very complex with 54 blood group antigens encoded by two adjacent genes on chromosome 1 – RHD and RHCE. The RHD gene encodes the RhD protein, a membrane bound protein on erythrocytes whose antigens are the most clinically important and immunogenic after those of the ABO system, and which can result in transfusion complications and haemolytic disease of the fetus and newborn. Some individuals have variants of the RhD proteins that are expressed more weakly than normal (“weak D”), or have some of the epitopes missing (“partial D”), and for which serological methods cannot give a uniform result. This provides a problem in blood transfusion, pregnancy, and blood donation, and often results in the use of the already sparse supply of RhDnegative blood units for the safety of the patient. In this project, eight samples with weak RhD antigen expression have been sequenced with regard to the RHD gene in order to determine the RhD phenotype of the individuals. In six of the samples, six single nucleotide polymorphisms and two deletions were found, all of which are rare but are previously known. For two of the samples, no mutations in exons or adjacent introns could be detected to explain the weak expression of RhD in those individuals.
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Fauré, Julien. "Régulation des GTPases de la famille RHO par RHO-GDI." Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10006.
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Les membres de la famille RHO de GTPpases monomériques sont des interrupteurs moléculaires impliqués dans la transduction de nombreux signaux aboutissant notamment à la motilité cellulaire et à la transcription de gènes. Notre travail a porté sur le complexe formé entre la protéine G RHO et RHO-GDI, son régulateur naturel. Les deux protéines sont associées dans le cytosol mais il est nécessaire qu'elles soient séparées pour que RHO puisse exercer sa fonction. Nous nous sommes intéressés aux stimuli permettant d'activer leur protéine G à partir de son complexe avec RHO-GDI. Nous avons d'abord mis au point dans un système d'expression eucaryote la production de complexes formés in vivo entre les GTPases de la famille RHO et RHO-GDI. La purification de ces complexes a abouti à la production de cristaux et devrait permettre l'étude de leurs structures tridimensionnelles. Nous avons utilisé ces complexes pour étudier l'effet des phosphoïnositides sur l'état d'association de RHO avec RHO-GDI. Nous avons montré que ces lipides induisaient une conformation pré-activée du complexe, sans toutefois dissocier les deux partenaires. La méthode double-hybride nous a permis de cloner par interaction avec RHO-GDI l'ensemble des membres de la famille RHO ainsi que plusieurs régulateurs potentiels. Cette methode a ensuite servi à étudier les zones de RHO susceptibles d'interagir avec RHO-GDI grâce à la production de mutants de RHOA. L'interaction entre la GTPase RHO et RHO-GDI met en oeuvre un résidu isoprène lié à l'extrémité c-terminale de RHO. Les mutants de RHOA ne portant pas ce résidu sont cependant toujours capables d'interagir avec RHO-GDI, vraissemblablement grâce à la zone d'insertion de RHO. Enfin, une technique d'overlay a été utilisée pour mettre en évidence des partenaires membranaires du complexe RHO/RHO-GDI activé par les phosphoïnositides. Une protéine de 32kda, lâchement attachée à la membrane, a ainsi été isolée comme régulateur potentiel du complexe RHO/RHO-GDI.
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Carrot, Laurent. "Rayon [rhô]-numérique." Lyon 1, 2003. http://www.theses.fr/2003LYO10190.
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Dans un premier temps, on s'intéressera aux propriétés du rayon [rhô] -numérique dans les espaces de Hilbert, notion initialement introduite par Sz. -Nagy et Foias à l'aide de la [rhô]-dilatation unitaire. Puis, l'étude du shift tronqué sur l(2n) permettra d'évaluer la constante dans une inégalité de Von Neumann avec contraintes, donnée par Badea et Cassier. Ensuite, à l'aide d'une condition sur la croissance de la résolvante, nous étendrons cette notion aux espaces de Banach. L'usage de la résolvante pour les définir assurera des classes C(p)"solides", qui conserveront de nombreuses propriétés. De plus, elles permettront de passer continuement de la classe des contractions à celle des opérateurs de rayon spectral inférieur à 1. Ces classes seront donc très riches, et elles pourraient fournir une alternative à la notion de [rhô]-dilatation unitaire pour les espaces de Banach. Enfin, nous étudierons des classes particulières d'opérateurs, dont notamment les shifts à poids sur l(1) et les nilpotents.
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Bucic, Ida. "Pollard's rho method." Thesis, Linnéuniversitetet, Institutionen för matematik (MA), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-85886.
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In this work we are going to investigate a factorization method that was invented by John Pollard. It makes possible to factorize medium large integers into a product of prime numbers. We will run a C++ program and test how do different parameters affect the results. There will be a connection drawn between the Pollard's rho method, the Birthday paradox and the Floyd's cycle finding algorithm. In results we will find a polynomial function that has the best effectiveness and performance for Pollard's rho method.
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Sisk, Christopher Andrew. "In Media Res." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5444.
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We are inundated by a constant feed of media that responds and adapts in real time to the impulses of our psyches and the dimensions of our devices. Beneath the surface, this stream of information is directed by hidden, automated controls and steered by political agendas. The transmission of information has evolved into a spiral of entropy, and the boundaries between author, content, platform, and receiver have blurred. This reductive space of responsive media is a catalyst for immense political and cultural change, causing us to question our notions of authority, truth, and reality.
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Fransson, Åsa. "Cell signaling by Rho and Miro GTPases : Studies of Rho GTPases in Cytoskeletal Reorganizations and of Miro GTPases in Mitochondrial Dynamics." Doctoral thesis, Uppsala University, Ludwig Institute for Cancer Research, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8514.
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The Ras superfamily of GTPases embraces six major branches of proteins: the Ras, Rab, Ran, Arf, Rho and Miro subfamilies. The majority of GTPases function as binary switches that cycle between active GTP-bound and inactive GDP-bound states. This thesis will focus primarily on the biological functions of the Rho and Miro proteins. The Rho GTPases control the organization of the actin cytoskeleton and other associated activities, whereas the Miro GTPases are regulators of mitochondrial movement and morphology.
A diverse array of cellular phenomena, including cell movement and intracellular membrane trafficking events, are dependent on cytoskeletal rearrangements mediated by Rho GTPases. Although human Rho GTPases are encoded by 20 distinct genes, most studies involving Rho GTPases have focused on the three representatives RhoA, Rac1 and Cdc42, which each regulate specific actin-dependent cellular processes. In an effort to compare the effects of all Rho GTPase members in the same cell system, we transfected constitutively active Rho GTPases in porcine aortic endothelial (PAE) cells and examined their effects on the organization of the actin cytoskeleton. We identified a number of previously undetected roles of the different members of the Rho GTPases. Moreover, we demonstrated that the downstream effectors of Rho GTPases have a broader specificity than previously thought.
In a screen for novel Ras-like GTPases, we identified the Miro GTPases (Mitochondrial Rho). In our characterization of Miro, we established that these proteins influence mitochondrial morphology and serve functions in the transport of mitochondria along the microtubule system. Additionally, we provided evidence that Miro can be under control of calcium signaling pathways. Mitochondria are highly dynamic organelles that undergo continuous change in shape and distribution. Defects in mitochondrial dynamics are associated with several neurodegenerative diseases. In conclusion, our findings have contributed to a deeper understanding of the biological roles of Rho and Miro GTPases.
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Castillo, Chabeco Boris. "Redox Regulation of Ras Proteins in Dictyostelium discoideum." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/1864.
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Reactive oxygen species are a normal consequence of life in an aerobic environment. However when they deviate from the narrow permissible range in cells, oxidative damage can occur. Dictyostelium discoideum is a model organism ideal for the study of cell signaling events such as those affected by oxidative stress. It was previously shown that Ras signaling in Dictyostelium is affected by genetic inactivation of the antioxidant enzyme Superoxide dismutase C (SodC) and in vitro data suggests that the NKCD motif of Ras is the redox target of superoxide.
The main objective of this project was to determine the mechanism of superoxide mediated Ras regulation in vivo. To accomplish the main objective, we cloned, and in some cases, mutated different Ras proteins and later determined their activity in wild type and sodC- cells. RasC and RasD showed normal activation in sodC- cells, however RasG and RasS displayed high Ras activity. These last two Ras proteins contain the NKC118D motif inside the nucleotide binding region. A mutation of cysteine118 to alanine in RasG rendered the protein less active in sodC- than the wild type RasG protein and a mutation alanine118 to cysteine in RasD conferred redox sensitivity to this small GTPase. Additionally, the propensity of RasG to be targeted by superoxide was evident when the environment of wild type cells was manipulated to induce the internal generation of superoxide through changes in the extracellular ion levels mainly magnesium. Lack of magnesium ions increased the intracellular level of superoxide and severely hampered directional cell migration. Chemotaxis of cells expressing RasG was negatively impacted by the absence of magnesium ions; however rasG- cells did not seem to be affected in their ability to perform chemotaxis. The last experiment implies that RasG is an important mediator of cell signaling during oxidative stress, responsible for preventing cells from continuing their developmental program. Our study suggests that the cysteine residue in the NKCD motif is essential for mediating the redox sensitivity of Ras proteins in Dictyostelium and that RasG is an essential mediator of the response to oxidative stress in this organism.
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Vanhoefer, Pit. "Study of B0->rho rho decays with the belle experiment." Diss., Ludwig-Maximilians-Universität München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:19-183537.
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Nguyen, Dinh Huu. "On [rho]-generic splitting varieties for Milnor K-symbols mod [rho]." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1905631291&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Clyde-Smith, Jodi. "Characterization of ras isoform activation by ras guanine nucleotide exchange factors /." St. Lucia, Qld, 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16393.pdf.
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Kazi, Samreen H. "Minimum tile-derived microsatellite markers improve the physical map of the soybean genome and the Flyer and Hartwig genetic map at Rhg, Rfs and yield loci /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1075682461&sid=1&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Thesis (M.S.)--Southern Illinois University Carbondale, 2005."Department of Molecular Biology, Microbiology and Biochemisty." Includes bibliographical references (leaves 154-176). Also available online.
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Wagner, Melanie. "Semisynthetische Ras-Lipoproteine Studium der intrazellulären Lokalisation, biologischen Aktivität und Membranassoziation /." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969669828.
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Tsipolitis, George. "[Omega omega] and [rho]+[rho-] production in two photon interactions at ARGUS." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74351.
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The reactions $ gamma gamma$ $ to$ 2$ pi sp+2 pi sp-2 pi sp0$ and $ gamma gamma to pi sp+ pi sp- pi sp0 pi sp0$ have been studied by using the ARGUS detector at the $e sp+e sp-$ storage ring DORIS II at DESY.In the $2 pi sp+2 pi sp-2 pi sp0$ final state the production of $ omega$-mesons is observed and in particular the reaction $ gamma gamma$ $ to$ $ omega omega$ is seen for the first time. The cross section for $ gamma gamma to omega omega$ is found to have an enhancement at $ sim$1.9GeV/c$ sp2$ of about 12 nb. The topological cross sections for the reactions $ gamma gamma$ $ to$ 2$ pi sp+2 pi sp-2 pi sp0$ and $ gamma gamma$ $ to$ $ omega pi sp+ pi sp- pi sp0$ are also measured.
The production of charged $ rho$-mesons is observed in the $ pi sp+ pi sp- pi sp0 pi sp0$ final state. The cross section for the reaction $ gamma gamma$ $ to$ $ rho sp+ rho sp-$ is measured for the first time. The cross section did not show a threshold enhancement similar to that found in the reaction $ gamma gamma$ $ to$ $ rho sp0 rho sp0$ and is about a factor of four smaller. A spin parity analysis of the $ rho sp+ rho sp-$ system shows that the cross section is dominated by the two amplitudes $J sp{P}$ = 0$ sp+$ and $J sp{P}$ = 2$ sp+$ with helicity 2.
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Agarwal, Amit Balkrishna. "FUNCTIONAL DIFFERENCES BETWEEN H-RAS AND K-RAS IN TRANSGENIC MOUSE TUMORS." VCU Scholars Compass, 2007. http://scholarscompass.vcu.edu/etd_retro/74.
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The ras genes, including Harvey ras (H-ras) and Kirsten ras (K-ras), were among the first oncogenes discovered, and are the most commonly mutated oncogenes in human cancer. The H-ras and K-ras proteins are 85% identical and share considerable functional overlap. However, there is increasing evidence for functional differences between the two proteins that may impart different properties to tumors arising from mutations in these two genes. To study the functional differences between H-ras and K-ras in an in vivo setting, we used two different transgenic mouse tumor models, MMTV-H-ras and MMTV-K-ras mice. The MMTV-H-ras mice were originally developed in Dr. Leder's lab and have been well characterized with regard to tumor properties. We created a similar line of transgenic mice expressing mutant K-ras (G12V) under the control of the MMTV promoter. Female mice of both lines develop primarily mammary tumors. We compared differences between the H-ras and K-ras lines with regard to age of tumor onset, rate of tumor growth, and rates of tumor proliferation and apoptosis. The tumors were also characterized by microarray analysis to look for genes that are differentially expressed in the two tumor types. Finally, the response of tumors to two common chemotherapeutic agents, doxorubicin and taxol, was also measured. We found that tumors in the MMTV-H-ras and MMTV-K-ras mice were similar with respect to several tumor properties, including age of onset, histopathology, and proliferation and apoptotic indices. While tumors from mice of these two genotypes clustered separately in an unsupervised analysis of gene expression profiles, the differentially expressed genes did not fall within any well-defined signaling pathways. However, drug studies indicated differences in response to doxorubicin between the two isoforms, with H-ras tumors responding better than K-ras tumors. In conclusion, our studies point to specific differences between H-ras and K-ras that may represent novel signaling pathways not currently known to be regulated by Ras. In spite of the few differences in properties of tumors arising from H-ras and K-ras mutation, there might be differences in response to chemotherapeutic agents that could have clinical significance.
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Dowding, Janet. "Cerium oxide nanoparticles act as a unique catalyst and scavenge nitric oxide and peroxynitrite and decrease RNS in vitro and in vivo." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5191.
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Cerium oxide nanoparticles (CeO2 NPs)(nanoceria) have been shown to possess a substantial oxygen storage capacity via the interchangeable surface reduction and oxidation of cerium atoms, cycling between the Ce4+ and Ce3+ redox states. Reduction of Ce4+ to Ce3+ causes oxygen vacancies or defects on the surface of the crystalline lattice structure of the particles, generating a cage for redox reactions to occur. The study of the chemical and biological properties of CeO2 NPs has expanded recently, and the methods used to synthesize these materials are also quite diverse. This has led to a plethora of studies describing various preparations of CeO2 NPs for potential use in both industry and for biomedical research. Our own work has centered on studies that measure the ability of water-based CeO2 NPs materials to reduce reactive oxygen and nitrogen species in biological systems, and correlating changes in surface chemistry and charge to the catalytic nature of the particles. The application in experimental and biomedical research of CeO2 NPs began with the discovery that water-based cerium oxide nanoparticles could act as superoxide dismutase mimetics followed by their ability to reduce hydrogen dioxide similar to catalase. While their ROS scavenging ability was well established, their ability to interact with specific RNS species, specifically nitric oxide (•NO) or peroxynitrite (ONOO-) was not known. The studies described in this dissertation focus on the study of RNS and cerium oxide nanoparticles. Our in vitro work revealed that CeO2 NPs that have higher levels of reduced cerium sites (3+) at the surface (which are effective SOD mimetics) are also capable of accelerating the decay of peroxynitrite in vitro. In contrast, CeO2 NPs that have fewer reduced cerium sites at the particle surface (which also exhibit better catalase mimetic activity) have •NO scavenging capabilities as well as some reactivity with peroxynitrite. Our studies and many others have shown cerium oxide nanoparticles can reduce ROS and RNS in cell culture or animal models. The accumulation of ROS and RNS is a common feature of many diseases including Alzheimer's disease (AD). Testing our CeO2 NPS in cortical neurons, we used addition of A? peptide as an AD model system. CeO2 NPs delayed A?-induced mitochondrial fragmentation and neuronal cell death. When mitochondrial ROS levels are increased, mitochondrial fission is activated by DRP1 S616 phosphorylation. Specifically, our studies showed the reduction of phosphorylated DRP1 S616 in the presence of CeO2 NPs. Results from our studies have begun to unravel the molecule mechanism behind the catalytic nature of how CeO2 NPs reduce ROS/RNS in biological systems and represents an important step forward to test the potential neuroprotective effects of CeO2 NPs in model systems of AD. A plethora of studies describing various preparations of CeO2 NPs for potential use in both industry and for biomedical research have been described in the past five years. It has become apparent that the outcomes of CeO2 NPs exposure can vary as much as the synthesis methods and cell types tested. In an effort to understand the disparity in reports describing the toxicity or protective effects of exposure to CeO2 NPs, we compared CeO2 NPs synthesized by three different methods; H2O2 (CNP1), NH4OH (CNP2) or hexamethylenetetramine (HMT-CNP1). Exposure to HMT-CNP1 led to reduced metabolic activity (MTT) at a 10-fold lower concentration than CNP1 or CNP2 and surprisingly, exposure to HMT-CNP1 led to substantial decreases in the ATP levels. Mechanistic studies revealed that HMT-CNP1 and CNP2 exhibited robust ATPase (phosphatase) activity, whereas CNP1 lacked ATPase activity. HMT-CNP1 were taken up into HUVECs far more efficiently than the other preparations of CeO2 NPs. Taken together, these results suggest the combination of increased uptake and ATPase activity of HMT-CNP1 may underlie the mechanism of the toxicity of this preparation of CeO2 NPs, and may suggest ATPase activity should be considered when synthesizing CeO2 NPs for use in biomedical applications. Overall the studies have uncovered two new catalytic activities for water-based CeO2 NPs (•NO scavenging and accelerated decay of peroxynitrite), demonstrated their ability to reduce RNS in an AD cell culture model as well as identifying a catalytic activity (phosphatase) that may underlie the observed toxicity of CeO2 NPs reported in other studies.Ph.D.
Doctorate
Molecular Biology and Microbiology
Medicine
Biomedical Sciences