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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Ovlivnění motoriky mláďat laboratorního potkana specifickým antagonistou AMPA receptorů / Influencing motor activity in laboratory rat offspring by specific antagonist of AMPA receptors.

Soukupová, Andrea January 2016 (has links)
The IEM 1460 is a potential age-specific anticonvulsant and an indicator of the distribution of AMPA receptor subtypes among rat brain cells. It is a derivative of adamantane, that was tested in previous studies on models of human myoclonic and generalized tonic-clonic seizures with promising results. In this thesis we evaluated its effect on the motor activity of rat offspring in the age of 12, 18 and 25 days, we used 90 animals in total . The effect was evaluated 30 minutes after intraperitoneal administration of IEM 1460 in two doses, 10 mg/kg or 20 mg/kg, and was compared to the control animals with physiological solution applied intraperitoneally in amount of 20 mg/kg. To test the animals we used Open field test, righting reflex, negative geotaxis, horizontal bar test, rope climbing test, regular and irregular horizontal ladder test. The tests were applied to animals in mentioned order. There were found significant changes influencing motor behaviour, primarily in the 12 days old animals with the dose of 20 mg/kg IEM 1460 and in the 25 days old animals with both doses of IEM 1460, 10 and 20 mg/kg. In the 18 days old animals the results were less significant. Powered by TCPDF (www.tcpdf.org)
112

Mapování kontaktních míst mezi eukaryotickým translačním iniciačním faktorem eIF3 a 40S ribozomální podjednotkou. / Mapping the contact points between eukaryotic translation initiation factor eIF3 and the 40S ribosomal subunit.

Kouba, Tomáš January 2013 (has links)
Translation initiation in eukaryotes is a multistep process requiring the orchestrated interaction of several eukaryotic initiation factors (eIFs) together with the small ribosomal subunit to locate the mRNA's translational start and to properly decode the genetic message that it carries. The largest of these factors, eIF3, forms the scaffold for other initiation factors to promote their spatially coordinated placement on the ribosomal surface. It is our long-standing pursuit to map the 40S-binding site of the yeast multisubunit eIF3 and here we present three new mutual interactions between these two macromolecules (i) The C-terminal region of the eIF3c/NIP1 subunit is comprised of the conserved bipartite PCI domain and we show that a short C-terminal truncation and two clustered mutations directly disturbing the PCI domain produce lethal or slow growth phenotypes and significantly reduce amounts of 40S-bound eIF3 in vivo. The extreme C-terminus directly interacts with small subunit ribosomal protein RACK1/ASC1, which is a part of the 40S head, and, consistently, deletion of ASC1 impairs eIF3 association with ribosomes. The PCI domain per se shows strong but unspecific binding to RNA, for the first time implicating this protein fold in protein-RNA interactions. We conclude that the c/NIP1...
113

Modelo computacional para o dimensionamento da subunidade em irrigação localizada / Computational model for design of sub-unit trickle irrigation systems

Castiblanco, Christian Jose Mendoza 16 May 2013 (has links)
Com o objetivo de fornecer ferramenta para auxiliar no dimensionamento da subunidade em irrigação localizada, especificamente para o método de irrigação por gotejamento, foi desenvolvido um Modelo Computacional, para o ambiente Windows em linguagem Visual Basic. Este modelo permitirá que esses sistemas de irrigação possam ser dimensionados sem negligenciar a perda localizada de carga ocasionada pela inserção dos emissores nas linhas laterais e pela inserção das linhas laterais nas linhas de derivação, o que muitas vezes causa desbalanço hidráulico destes sistemas. O modelo considera todas as etapas do desenvolvimento do projeto de irrigação para dimensionamento da subunidade, as características agronômicas do solo, do clima e da cultura, determinando-se condições de armazenamento da água no solo, a evapotranspiração e o ciclo de desenvolvimento da cultura. Para o dimensionamento da subunidade o modelo utiliza parâmetros como, declividade do terreno, pressão de entrada na linha, espaçamento entre emissores e linhas laterais, diâmetro da linha lateral, comprimento da linha de derivação, variação máxima de carga de pressão na lateral e variação máxima de vazão dos emissores. Estes dois últimos parâmetros considerados como critério de projeto. Por último, as características do emissor, sua vazão e área de protrusão, assim como o conector utilizado na conexão da linha lateral com a linha de derivação, que determinarão as perdas localizadas de carga. Com esses parâmetros o modelo determina e fornece como resultado, de forma ágil e precisa, o comprimento máximo da linha lateral pelo método da aproximação hidráulica, a perda localizada de carga, ocasionada pela inserção dos emissores na linha, expresso em termos de comprimento equivalente, os diâmetros para a linha de derivação, a perda localizada de carga, ocasionada pela inserção dos conectores na linha de derivação e o numero de linhas laterais conectadas na linha de derivação. Apresentando a tabela do dimensionamento da linha e o gráfico do perfil de pressão. Nos dimensionamentos realizados, utilizando os tipos de emissores existentes na base de dados do modelo, o emissor que proporcionou maior perda localizada de carga, em termos de comprimento equivalente, foi o emissor in-line (Uniram) com 0,758 m, resultando acréscimo do comprimento da linha lateral em 197,25 m, se desconsideradas as perdas localizadas de carga. O emissor que resultou menor acréscimo nas perdas localizadas de carga foi o do tipo online (Katif), com 0,11 m de comprimento equivalente, correspondendo 29 m de acréscimo no comprimento da linha lateral se desconsideradas as perdas localizadas de carga. Portanto, o modelo permite realizar as comparações do dimensionamento da subunidade considerando e desconsiderando as perdas localizadas de carga, possibilitando observar as diferenças resultantes no dimensionamento da subunidade quando negligenciadas estas perdas. / This research had the objective to develop a tool to design drip irrigation systems subunit. The computational model was developed to Windows in Visual Basic language. The model takes into account in the design both the local head loss due to the insertion of emitters in the lateral line and the insertion the lateral line in the main line. These local head losses are responsible for hydraulic unbalance of this type of irrigation system. The model considers all irrigation project steps for design of a sub-unit: soil properties, climate and crop characteristics. The model determines soil water content, evapotranspiration and crop cycle stage. In the sub-unit design, the model utilizes some parameters, such as, slope, pressure head in the main line, space between emitters and lateral lines, lateral line diameter, length of derivation line, maximum variation of pressure head in the lateral line, and maximum variation of emitters discharge. Emitter characteristics, its discharge and protrusion area, connector used to connect the lateral line into the derivation line, are also taken into account in the model. The model with previous parameters determines and provides precisely results of: maximum length of lateral line by hydraulic approximation method; local head losses, due to emitter insertion into lateral line, expressed as equivalent length losses; derivation line diameter; local head loss, due to connector insertion in the derivation line; and number of lateral line connected in the derivation line. It shows a design table and pressure profile. It was utilized some emitter types in the model database. The in-line emitter (Uniram) showed the biggest local head losses, 0,758 m in terms of equivalent length, it resulted in a increment in the lateral line length of the 197,25 m compared to lateral line without consider the local losses. Emitter online type (Katif) showed the lowest local head losses, 0,11 m of equivalent length which correspond 29 m in the lateral line length. Therefore, the model allows to compare the differences in the sub-unit design when it is considered the local head losses with the sub-units design neglecting theses losses.
114

Studies of the assembly pathway of human ATP synthase

Douglas, Corsten Perrie Louise Claire January 2017 (has links)
Human mitochondrial ATP synthase is an enzyme containing 18 unlike subunits located in the inner mitochondrial membrane (IMM), where the catalytic F1 domain extends into the mitochondrial matrix and the FO domain, which contains the c8-ring rotor, the a-subunit and the supernumerary subunits, is anchored in the IMM. All the subunits, apart from the a- and A6L-subunits, are encoded in the nucleus and require transport into the mitochondria before being assembled. The a- and A6L-subunits are encoded on the mitochondrial genome. The respiratory complexes generate the proton motive force (PMF), which ATP synthase uses to generate ATP from ADP and Pi. Rotation of the α- and β-subunits with the central stalk γ-, δ- and ε-subunits is prevented by coupling the F1 domain to the FO domain via the peripheral stalk (the OSCP-, F6-, d- and b-subunits). ATP hydrolysis is prevented by the natural inhibitor of the enzyme, IF1, binding to the F1 domain. In addition to the aand, b-subunits, the FO domain contains the c8-ring and six supernumerary subunits not involved in the catalytic activity of ATP synthase. The roles of five of these subunits in the assembly of ATP synthase, the e-, f-, g-, DAPIT- and 6.8 kDa proteolipid-subunits, were investigated by suppressing or disrupting their expression individually. The e-subunit is the first of the supernumerary subunits to assemble, then the g-subunit followed by the f-, 6.8 kDa proteolipid- and DAPIT-subunits. All five supernumerary subunits investigated were required to facilitate the dimerisation and oligomerisation of ATP synthase. The e-, f- and g-subunits were found to be important for maintaining mitochondrial respiratory capacity.
115

Proposição de um método para concepção da estratégia de produção: uma abordagem a partir do conceito de subunidades estratégicas de negócios

Dupont, André Cardoso 28 March 2011 (has links)
Submitted by William Justo Figueiro (williamjf) on 2015-06-29T21:41:13Z No. of bitstreams: 1 55.pdf: 2692429 bytes, checksum: f93c564b596e3eb883b24495f89a5a7c (MD5) / Made available in DSpace on 2015-06-29T21:41:13Z (GMT). No. of bitstreams: 1 55.pdf: 2692429 bytes, checksum: f93c564b596e3eb883b24495f89a5a7c (MD5) Previous issue date: 2011-03-28 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O fenômeno da “nova economia” – combinação da globalização com a velocidade da alta tecnologia – insere no ambiente empresarial um conjunto de complexidades do ponto de vista da gestão. Primeiramente, com o aumento de competidores (aumento da oferta), em função da globalização, e a não correspondência de aumento em termos de mercado consumidor (demanda), as organizações tendem a ampliar sua gama de produtos ofertados ao mercado para conseguir aumento de escala de produção. Além disso, com a difusão da informação, propiciada também pela ”nova economia”, as melhores práticas, em termos conceituais, estão acessíveis a todos. A diferença, portanto, entre sistemas produtivos e organizações pode não estar nas práticas e técnicas em si, mas, em como essas são entendidas a partir da concepção de distintas estratégias de produção. O referencial teórico busca apresentar os principais aspectos teóricos acerca da estratégia de produção: i) competitividade; ii) estratégia competitiva; iii) níveis estratégicos; iv) estratégia de produção; v) dimensões competitivas; vi) modelos de concepção de estratégia de produção; vii) Fábricas Focalizadas; e viii) Unidades Estratégicas de Negócios (UENs). Visando a enriquecer os conceitos pesquisados, a pesquisa apresenta proposições teóricas a partir da literatura anteriormente analisada: i) Subunidades Estratégicas de Negócios (SubUENs); ii) comparações entre os conceitos de FFs, UENs e SubUENs; iii) análise de resultados por SubUEN; e iv) aspectos econômicos da estratégia. A partir desde cenário, o presente trabalho propõe um método geral para auxiliar na concepção da estratégia de produção das empresas. No entanto, a partir da percepção do aumento da diversificação das linhas de produtos nas empresas e da decorrente ampliação da complexidade de gestão nas mesmas, percebe-se uma lacuna nos conceitos existentes no âmbito da estratégia de produção e se propõe a adoção do conceito de SubUENs. Assim, a proposta desta pesquisa é desenvolver um método que, com a adoção do conceito de SubUEN, possa contribuir para a construção da estratégia de produção alinhando as dimensões econômico-financeira, mercadológica e produtiva das empresas industriais. O método de pesquisa foi o Design Research, e a etapa empírica do trabalho foi realizada em empresa do setor metal-mecânico, localizada em Caxias do Sul (RS). O método proposto teve como base cinco fontes de informação: i) os conceitos existentes no âmbito da estratégia de produção; ii) proposições teóricas da pesquisa; iii) conhecimento empírico de um grupo de especialistas, que avaliou o método antes de sua aplicação; iv) contribuição dos profissionais da empresa e do próprio pesquisador a partir da aplicação do método; e v) a avaliação do método a partir da aplicação do mesmo em ambiente empresarial. Ao término do estudo, chegou-se a uma proposta final de método que está disponível para novas aplicações. / The so-called “new economy” – a combination of globalization with the speed of high technology – enter the business environment a set of complexities in terms of management. First, with the increase of competitors (increasing supply), due to globalization, and the mismatch in terms of increase of consumer market (demand), organizations tend to expand their range of products offered to the market to achieve scale-up production. Moreover, with the dissemination of information, made possible also by the “new economy”, best practices, in conceptual terms, are accessible to all. The difference therefore between systems and organizations may not be in the practices and techniques themselves, but rather in how these are understood from the design of different production strategies. The theoretical framework seeks to present the main theoretical aspects concerning the production strategy: i) competitiveness, ii) competitive strategy, and iii) strategic levels, iv) production strategy; v) competitive dimensions vi) design models of manufacturing strategy; vii) Focused Factories and viii) Strategic Business Units (SBUs). To enrich the concepts surveyed the research presents theoretical propositions from the literature reviewed above: i) Strategic Business SubUnits (SubSUBs), ii) comparisons between the concepts of Focused Factories, SBUs and SubSUBs iii) analysis of results by SubSBU and iv) economic aspects of the strategy. Starting from scenario, this research proposes a general method to assist in designing the production strategy of the enterprises. However, from the perception of increased diversification of product lines within companies and the consequent expansion of the complexity of managing the same, a gap was perceived in the existing concepts in the context of manufacturing strategy and proposes the adoption of the concept of SubSBUs. Thus, the purpose of this research is to develop a method that, by adopting the concept of SubSUBs could contribute to the construction of manufacturing strategy by aligning the economic-financial, marketing and production of industrial companies. The research method was the Design Research, and the stage of empirical research was conducted in a company of the metal-mechanic located in Caxias do Sul (RS). The proposed method was based on five sources of information: i) the existing concepts in the context of manufacturing strategy, ii) theoretical propositions of the research; iii) empirical knowledge of an expert group that evaluated the method before its application; iv) contribution of professionals in the company and the researcher from applying the method and v) the evaluation method from the application of it in a business environment. At the end of the research was a proposal to end the method that is available for new applications.
116

Structural and Functional Aspects of β1 Integrin Signalling

Nilsson, Stina January 2006 (has links)
<p>Integrins are transmembrane glycoproteins primarily mediating interactions of cells with the extracellular matrix. Each receptor is a complex of one α- and one β-subunit with affinity for a diverse set of ligands. A prerequisite for ligand binding, and subsequent events, is the activation of integrins by cytoplasmic signals that confer a large conformational change to the extracellular domain.</p><p>In this thesis, the role of a cytoplasmic threonine-cluster, conserved in several β subunits, in β1-integrin activation was investigated. Phosphorylation of these residues is postulated to regulate β2 and β3 integrin affinity for ligands, but it has not been shown so far to occur for β1. Residue T788, but not T789, was established as a site of critical importance for inside-out activation of β1 integrins by mutagenesis to alanine. In contrast to β1-T788A, a phospho-mimicking mutation, β1-T788D, expressed the conformation sensitive 9EG7-epitope and mediated normal cell adhesion. In addition, the T788D mutation did not interfere with binding of the talin head domain, an interaction important for integrin activation. Thus, phosphorylation of T788 in integrin β1 was concluded to be compatible with inside-out receptor activation, in line with β2 and β3 integrin regulation. </p><p>Focal adhesion kinase (FAK) is activated after integrin ligation and is, together with Src, one of the central players in integrin-mediated events. Phosphatidylinositol 3-kinase (PI3K) is thought to be activated by binding to FAK. However, a novel, major β1-integrin signalling pathway to activate PI3K was identified, which is FAK- and Src-independent.</p><p>Growth factor induced stimulation of extracellular signal-regulated kinase (Erk) is largely dependent on signals from integrin mediated adhesion to pass checkpoints downstream of Ras. The mechanisms by which β1-integrins mediate Erk-activation were characterized by pin-pointing what phosphorylation sites on the mitogen-activated protein (MAP) kinases and their effector proteins were FAK-dependent. The results indicated that β1 integrins can promote Erk activation by FAK-dependent mechanisms at the levels of both cRaf and Mek, and in addition, a FAK-independent checkpoint at the level of Mek activation.</p>
117

Neurosteroids Induce Allosteric Effects on the NMDA Receptor : Nanomolar Concentrations of Neurosteroids Exert Non-Genomic Effects on the NMDA Receptor Complex

Johansson, Tobias January 2008 (has links)
<p>The neurosteroids constitute a group of powerful hormones synthesized and acting in the central nervous system. They participate in a number of important central processes, such as memory and learning, mood and neuroprotection. Their effects emerge from rapid interactions with membrane bound receptors, such as the N-methyl-D-aspartate (NMDA) receptor, the gamma-amino-butyric acid receptor and the sigma 1 receptor. The mechanisms of action are separate from classical genomic interactions. </p><p>The aims of this thesis were to identify and characterize the molecular mechanisms underlying the effects of nanomolar concentrations of neurosteroids at the NMDA receptor. </p><p>The results show that the neurosteroids pregnenolone sulfate (PS) and pregnanolone sulfate 3α5βS) differently modulate the NMDA receptor, changing the kinetics for the NMDA receptor antagonist ifenprodil, through unique and separate targets at the NR2B subunit. The effects that appear to be temperature independent were further confirmed in a calcium imagining functional assay. A second functional study demonstrated that PS and 3α5βS affect glutamate-stimulated neurite outgrowth in NG108-15 cells. </p><p>Misuse of anabolic androgenic steroids (AAS) has powerful effects on emotional states. Since neurosteroids regulate processes involved in mood it can be hypothesised that AAS can interact with the action of neurosteroids in the brain. However, chronic administration of the AAS nandrolone decanoate did not alter the allosteric effects of PS or 3α5βS at the NMDA receptor, but changed the affinity for PS, 3α5βS and dehydroepiandrosterone sulfate to the sigma 1 receptor. The results also showed that the neurosteroids displace <sup>3</sup>H-ifenprodil from the sigma 1 and 2 receptors without directly sharing the binding site for <sup>3</sup>H-ifenprodil at the sigma 1 receptor. The decreased affinity for the neurosteroids at the sigma 1 receptor may be involved in the depressive symptoms associated with AAS misuse.</p><p>The NMDA receptor system is deeply involved in neurodegeneration and the NMDA receptor antagonist ifenprodil exert neuroprotective actions. The findings that neurosteroids interact with ifenprodil at the NMDA receptor may be an opportunity to obtain synergistic effects in neuroprotective treatment.</p>
118

Structural and Functional Aspects of β1 Integrin Signalling

Nilsson, Stina January 2006 (has links)
Integrins are transmembrane glycoproteins primarily mediating interactions of cells with the extracellular matrix. Each receptor is a complex of one α- and one β-subunit with affinity for a diverse set of ligands. A prerequisite for ligand binding, and subsequent events, is the activation of integrins by cytoplasmic signals that confer a large conformational change to the extracellular domain. In this thesis, the role of a cytoplasmic threonine-cluster, conserved in several β subunits, in β1-integrin activation was investigated. Phosphorylation of these residues is postulated to regulate β2 and β3 integrin affinity for ligands, but it has not been shown so far to occur for β1. Residue T788, but not T789, was established as a site of critical importance for inside-out activation of β1 integrins by mutagenesis to alanine. In contrast to β1-T788A, a phospho-mimicking mutation, β1-T788D, expressed the conformation sensitive 9EG7-epitope and mediated normal cell adhesion. In addition, the T788D mutation did not interfere with binding of the talin head domain, an interaction important for integrin activation. Thus, phosphorylation of T788 in integrin β1 was concluded to be compatible with inside-out receptor activation, in line with β2 and β3 integrin regulation. Focal adhesion kinase (FAK) is activated after integrin ligation and is, together with Src, one of the central players in integrin-mediated events. Phosphatidylinositol 3-kinase (PI3K) is thought to be activated by binding to FAK. However, a novel, major β1-integrin signalling pathway to activate PI3K was identified, which is FAK- and Src-independent. Growth factor induced stimulation of extracellular signal-regulated kinase (Erk) is largely dependent on signals from integrin mediated adhesion to pass checkpoints downstream of Ras. The mechanisms by which β1-integrins mediate Erk-activation were characterized by pin-pointing what phosphorylation sites on the mitogen-activated protein (MAP) kinases and their effector proteins were FAK-dependent. The results indicated that β1 integrins can promote Erk activation by FAK-dependent mechanisms at the levels of both cRaf and Mek, and in addition, a FAK-independent checkpoint at the level of Mek activation.
119

Neurosteroids Induce Allosteric Effects on the NMDA Receptor : Nanomolar Concentrations of Neurosteroids Exert Non-Genomic Effects on the NMDA Receptor Complex

Johansson, Tobias January 2008 (has links)
The neurosteroids constitute a group of powerful hormones synthesized and acting in the central nervous system. They participate in a number of important central processes, such as memory and learning, mood and neuroprotection. Their effects emerge from rapid interactions with membrane bound receptors, such as the N-methyl-D-aspartate (NMDA) receptor, the gamma-amino-butyric acid receptor and the sigma 1 receptor. The mechanisms of action are separate from classical genomic interactions. The aims of this thesis were to identify and characterize the molecular mechanisms underlying the effects of nanomolar concentrations of neurosteroids at the NMDA receptor. The results show that the neurosteroids pregnenolone sulfate (PS) and pregnanolone sulfate 3α5βS) differently modulate the NMDA receptor, changing the kinetics for the NMDA receptor antagonist ifenprodil, through unique and separate targets at the NR2B subunit. The effects that appear to be temperature independent were further confirmed in a calcium imagining functional assay. A second functional study demonstrated that PS and 3α5βS affect glutamate-stimulated neurite outgrowth in NG108-15 cells. Misuse of anabolic androgenic steroids (AAS) has powerful effects on emotional states. Since neurosteroids regulate processes involved in mood it can be hypothesised that AAS can interact with the action of neurosteroids in the brain. However, chronic administration of the AAS nandrolone decanoate did not alter the allosteric effects of PS or 3α5βS at the NMDA receptor, but changed the affinity for PS, 3α5βS and dehydroepiandrosterone sulfate to the sigma 1 receptor. The results also showed that the neurosteroids displace 3H-ifenprodil from the sigma 1 and 2 receptors without directly sharing the binding site for 3H-ifenprodil at the sigma 1 receptor. The decreased affinity for the neurosteroids at the sigma 1 receptor may be involved in the depressive symptoms associated with AAS misuse. The NMDA receptor system is deeply involved in neurodegeneration and the NMDA receptor antagonist ifenprodil exert neuroprotective actions. The findings that neurosteroids interact with ifenprodil at the NMDA receptor may be an opportunity to obtain synergistic effects in neuroprotective treatment.
120

Examination of neonatal immunity in IL-13 receptor alpha 1 deficient mice

Hardaway, John C., Zaghouani, Habib. January 2009 (has links)
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on January 5, 2010). Vita. Thesis advisor: Habib Zaghouani. Includes bibliographical references.

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