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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.
161

Partial Oxidation of Ethene to Ethylene Oxide in Microchannel Reactors: Partial Oxidation of Ethene to Ethylene Oxidein Microchannel Reactors

Kursawe, Ansgar 11 December 2009 (has links)
In der vorliegenden Arbeit wurde die heterogen katalysierte Oxidation von Ethen zu Ethylenoxid an Silberkatalysatoren untersucht. Ziel dieser Arbeit war es, Mikrostrukturreaktoren für schnelle und stark exotherme Oxidationsreaktionen zu erproben und diese Epoxidation diente als Modellreaktion. Gleichzeitig wurden explosions- und flammhemmende Eigenschaften des Mikrostrukturreaktors ausgenutzt, um die partielle Oxidation von Ethen zu Ethyenoxid im Explosionsbereich (> 9% Sauerstoff) ohne Sicherheitsprobleme zu ermöglichen. Um die gesteckten Ziele zu erreichen wurden zwei parallele Lösungswege beschritten. Zunächst wurden modulare Mikrostrukturreaktoren und geeignete mikrostrukturierte Katalysatorträger entwickelt, um Untersuchungen verschiedener katalytischer Beschichtungen in dieser neuen und nicht allgemein verfügbaren Reaktorbauweise zu ermöglichen. Zur katalytische Erprobungen dieser Konstruktion war es notwendig, geeignete Beschichtungstechniken zur Immobilisierung katalytisch aktiver Spezies zu entwickeln. Durch die Bauweise dieser Reaktoren als Wandreaktor erschien es anfänglich nicht möglich, kommerziell verfügbare pellet-artige Katalysatoren zu verwenden. Daher wurden, parallel zur Konstruktion der modularen Mikroreaktoren, verschiedene auf Silber basierende Beschichtungstechniken hinsichtlich ihrer Eignung für diese Reaktion erprobt. Zur Erprobung kamen u.a. Silberimmobilisierung in einem durch anodischen Oxidation erzeugen Porensystem bzw. einer durch Sol-Gel Beschichtung erzeugten a-Aluminiumoxid Schicht und die Abscheidung von metallischem Silber per Vakuumbeschichtung auf einem Trägermaterial. Zuletzt wurde die Immobilisierung eines gemahlenen, kommerziellen Katalysators per elektrostatischer Pulverabscheidung auf einem entsprechend präparierten Trägermaterial vorgenommen und erfolgreich erprobt. Die wichtigste Erkenntnis dieser Arbeit aus chemisch-katalytischer Sicht ist der enorm positive Einfluss hoher Sauerstoffkonzentrationen auf die Selektivität und gleichzeitig den Umsatz des umzusetzenden Ethylens. Wird die Sauerstoffkonzentration von unter 10% auf bis zu 80% erhöht, so steigt die Selektivität zu Ethylenoxid um ca. 10% an und simultan kann der Umsatzgrad abhängig vom Katalysator und der Reaktortemperatur um den Faktor 2 bis 10 gesteigert werden. Diese Beobachtung wurde für jeden funktionierenden Katalysator gemacht, unabhängig von dessen Herstellung. Mittels Promotoren wie Cs-Salzen und Stickoxiden konnte die Selektivität in Abwesenheit gängiger Moderatoren wie Chlorkomponenten auf 70% (Cs-Salze) bzw. 75% (NOx) gesteigert werden. Verfahrenstechnisch ist festzuhalten, dass Mikrostrukturreaktoren gleich welcher Bauweise unter allen Reaktionsbedingungen thermisch stabil und beherrschbar blieben. Es wurden Umsatzgrade bis 99% bezüglich Ethen erzielt bzw. Reaktionstemperaturen von über 630 K bei einem binären Ethylen-Sauerstoff Gemisch (20%/80%) angewendet. Angesichts adiabater Temperaturerhöhungen von mehr als 3000 K konnte dennoch ein stabiler Betrieb des Reaktors festgestellt werden. Diese thermische Stabilität war bei Katalysatoren in Festbettreaktoren nicht gegeben.
162

Klinická klasifikace sekvenčních variant v nekódujících regulačních oblastech genů predisponujících ke vzniku karcinomu prsu. / Clinical classification of sequence variants in non-coding regulatory regions in breast cancer susceptibility genes.

Bubáková, Eliška January 2019 (has links)
Inactivation of tumor supressor gene BRCA1 causes a life-long risk of breast carcinoma development. Genetic screenings of indicated individuals from high-risk families help to identify large number of sequence variants in known predisposing genes. Majority of discovered variants doesn't have clinical significance yet which causes a big problem for diagnostics. Some of these variants are found within regulatory non-coding regions of gene. A part of the clinical classification of variants is their functional characterization. The goal of this thesis was to create a model system for functional characterization of variants in non-coding regions and to verify its function. Model system was based on targeted gene manipulation by co-transfecting CRISPR-Cas9 construct and donor construct that contained a portion of BRCA1 gene sequence with analyzed modifications, into U2 OS cells. The cells have stably integrated DR-GFP system which allows the activity of homologous recombination (HR) to be determined. Monoallelic modifications were induced into U2 OS cells. These modifications were in a Kozak sequence region of BRCA1 gene. Expression level of BRCA1 mRNA was determined by qRT-PCR, which showed the same levels of mRNA in all cells with analyzed alterations. Next, expression level of BRCA1 protein was...
163

Molekulárně genetická analýza u Niemann-Pickovy choroby typu C / Molecular genetic analysis in Niemann-Pick type C disease

Marešová, Ivona January 2013 (has links)
Niemann-Pick disease type C (NPC) is a rare, severe disease with autosomal recessive inheritance. Disease is caused by pathogenic mutations located in genes NPC1/NPC2. These genes encode lysosomal non enzymatic NPC1/NPC2 proteins that are part of lipid transport. As a result of malfunction of these proteins intracellular accumulation of lipids occurs, in particular free cholesterol and glycolipids. Causal therapy is currently still unsatisfactory therefore new therapies are evolved. However these therapies depend on whether the patient cells contain at least residual amount of transcript NPC1 gene. In a group of patiens, for which a fibroblast culture was available, I analyzed the effect of pathogenic mutations on the expression level of the transcript. Results showed that for all pathogenic mutations transcript level is low, but detectable. Moreover, I characterized the structure of the NPC1 gene promoter. By sequence analysis I found polymorphisms rs8099071, rs28403610, rs2981422, rs1652354, rs1788774, rs1788772 in promoter. On the basis of the composition of polymorphisms in individual patiens, I estimate six different haplotypes. I performed mutation analysis in DNA of recently diagnosed patient. I found only one pathogenic mutation p.I1061T (c.3182T> C) in the NPC1 gene. Therefore I tested...
164

Struktur und Funktion des Gens für das translationell kontrollierte Tumorprotein (TCTP)

Thiele, Holger 28 February 2000 (has links)
Das translationell kotrollierte Tumorprotein (TCTP) ist ein bei Eukaryonten vorkommendes hochkonserviertes Protein, das eine Rolle bei der Pathogenese allergischer Erkrankungen spielt. Bei atopischen Kindern vermittelt es eine IgE abhängige Histaminfreisetzung aus basophilen Granulozyten. Die zugrundeliegenden Mechanismen sind jedoch unklar. TCTP hat die Eigenschaft, an das Tubulin des Zytoskeletts der Zelle zu binden und besitzt eine hohe Affinität für Kalzium. Seine Synthese wird auf dem transkriptionellen und translationellen Niveau reguliert. Eine früher angenommene spezifische Funktion in Tumorzellen konnte nicht bestätigt werden. Das für TCTP kodierende Gen wird als TPT1 bezeichnet. Um die molekulare Basis für die Kontrolle der Synthese des TCTP zu verstehen, wurden in dieser Arbeit Struktur und Funktion des TPT1-Gens bei Mensch und Kaninchen untersucht. Erstmalig wurde die vollständige Struktur eines Säuger-TPT1-Gens durch Klonierung und Sequenzierung aufgeklärt und die funktionelle Rolle des Promotors analysiert. Das 3,8 kb große Kaninchengen wird durch fünf Introns unterbrochen, und kodiert für zwei mRNAs von 843 und 1163 nt, die sich in der Länge der 3' untranslatierten Region unterscheiden. Sie entstehen durch alternative Polyadenylierung. Vom Human-Gen wurden genomische Rekombinanten isoliert und seine vorläufige Struktur ermittelt. Es besitzt eine identische Intron/Exon Architektur und unterscheidet sich nur geringfügig in der Länge der Introns. Auch bei der Expression des Human-Gens entstehen zwei mRNAs. Hybridisierungsexperimente mit RNA aus 10 Kaninchen- und 50 Human-Geweben zeigten, daß beide TCTP mRNAs in allen untersuchten Geweben in ähnlichem Verhältnis zueinander exprimiert werden. Die Gesamtkonzentrationen der TCTP- mRNAs unterschied sich jedoch in verschiedenen Gewebegruppen bis zum Faktor 100. Dies deutet auf eine ausgeprägte Regulation der gewebsspezifischen Transkription hin. Die Promotorstrukturen von 1,2 kb 5'-flankierender Sequenzen des Kaninchen- Gens wurden mit Computerprogrammen auf Bindungsstellen für Transkriptionsfaktoren analysiert. Für funktionelle Aussagen wurden Promotorfragmente mit dem Chloramphenicol-Acetyltransferase-Gen (cat) gekoppelt und die Promotoraktivität durch Bestimmung der CAT-Enzymaktivität nach Zelltransfektionen ermittelt. Ein minimaler Promotor von 66 bp Länge, der eine TATA-Box enthält, konnte eingegrenzt werden. Die maximale Promotoraktivität, die 90% im Vergleich zum starken Thymidinkinase-Promotor betrug, war mit einem 290 bp langem Fragment assoziiert und enthielt eine SP-1, zwei AP-1/CREB und zwei ETS Bindungsstellen. Diese Konstellation ist ein häufiges Merkmal von Genen, die wie das TPT1-Gen durch Phorbolester und Lipopolysaccharide induzierbar sind. Im Sequenzbereich bis -160 sind die Promotoren des Human- und des Kaninchen-Gens sehr ähnlich (89% Homologie), alle Bindungsorte für Transkriptionsfaktoren sind hier konserviert. Weiterhin wurde im Kaninchengenom eine Vielzahl von prozessierten TPT1- Pseudogenen.gefunden. Sechs von ihnen und ihre genomisch-flankierenden Integrationsorte wurden sequenziert. Sie repräsentierten beide mRNA Typen und waren zu über 99% zu den korrespondierenden mRNAs homolog. Die Leserahmen aller Pseudogene waren intakt, bei zwei Pseudogenen war die Aminosäuresequenz sogar unverändert erhalten. Die durch CAT-Assays getestete Transkriptionsaktivität der 5'flankierenden Region eines Pseudogens zeigte eine Aktivität von über 15% gegenüber dem authentischen TPT1-Promotor. Dies ist ein Indiz für eine mögliche Expression von TPT1 Pseudogenen in vivo. / The translationally controlled tumor protein (TCTP) is a conserved eukaryotic protein, which is involved in the pathogenesis of allergic diseases. In atopic children it has been reported to mediate histamine release from basophilic leukocytes in an IgE dependent way. The underlying mechanism, however, is unknown. TCTP is characterized by an efficient binding to tubulin of cytoskeletal structures and by a high calcium affinity. Its synthesis is regulated at the transcriptional and translational level. A specific function in tumor cells, which was assumed initially, could not be confirmed. The gene coding for TCTP is called TPT1. To understand the molecular basis for the control of TCTP expression structure and function of the human and rabbit TPT1 genes were investigated including their promoter regions. The first mammalian TPT1 gene (rabbit) was cloned and sequenced. It consists of 3.8 kb and is interrupted by five introns. Two mRNAs of 843 and 1163 nt length are transcribed differing in their 3'untranslated regions. They are generated by alternative polyadenylation. Furthermore genomic recombinants were isolated containing the human TPT1 gene and a preliminary structure of the gene was established. The human gene has the same intron/exon architecture as the rabbit gene just differing in the length of its introns. Human multi-tissue dotblots revealed an identical transcription pattern for both mRNAs. The concentration of the TCTP mRNAs differed up to the factor 100 between different tissues, indicating distinct tissue specificity in transcriptional control. 1.2 kb 5'flanking promoter structures were analyzed for transcription factor binding sites. For functional studies TPT1 promoter fragments were fused to the chloramphenicol acetyltransferase (CAT) reportergene and assayed by cell transfection and CAT enzyme activity. A basic promoter of 66 bp length containing a TATA box could be defined. Maximal promoter activity of 90% compared to the strong thymidine kinase promoter was associated with a fragment of 290 bp containing a SP-1, two AP-1/CREB and two ETS binding sites. This is a common feature of genes like TPT1, which are inducible by phorbolesters and lipopolysaccharides. Furthermore, numerous processed TPT1 pseudogenes were found spread through the rabbit genome. Six pseudogenes and their flanking genomic integration sites were sequenced. They represented both mRNA types and were at least 99% homologous to the corresponding mRNAs. In all pseudogenes the open reading frames were retained and in two of them the original amino acid sequence was even conserved completely. The 5'flanking region of one pseudogene was tested for transcriptional activity by CAT assays and revealed an activity of about 15% of the authentical TPT1 promoter. This could suggest a possible expression of TPT1 pseudogenes in vivo.
165

Os Cadernos do Promotor: as ações do Tribunal do Santo Ofício no Maranhão e Grão-Pará (1640-1750)

CARVALHO, Leila Alves de 25 June 2018 (has links)
Submitted by Rosana Moreira (rosanapsm@outlook.com) on 2018-10-10T18:49:44Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_CadernosPromotorAcoes.pdf: 4357352 bytes, checksum: b777b12f6a51002d8867d481eb8a4819 (MD5) / Approved for entry into archive by Edisangela Bastos (edisangela@ufpa.br) on 2018-10-16T18:53:20Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_CadernosPromotorAcoes.pdf: 4357352 bytes, checksum: b777b12f6a51002d8867d481eb8a4819 (MD5) / Made available in DSpace on 2018-10-16T18:53:20Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_CadernosPromotorAcoes.pdf: 4357352 bytes, checksum: b777b12f6a51002d8867d481eb8a4819 (MD5) Previous issue date: 2018-06-25 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esta pesquisa tem por objetivo analisar como ocorreram as ações do Tribunal do Santo Ofício na Amazônia lusa – Maranhão e Grão-Pará – num recorte temporal mais que secular, entre 1640 e 1750. O intuito é perceber as estratégias empregadas pelo Santo Ofício como forma de espraiar seu poder em um período anterior à Visitação Pombalina de 1763, dentro da realidade da colônia de vasta extensão e diversas populações. Neste contexto, buscamos identificar os agentes do Santo Ofício, assim como, as formas utilizadas para implantar o disciplinamento moral e religioso neste espaço e nesta sociedade. Nos embasamos, como fonte principal, nos manuscritos dos Cadernos do Promotor da Inquisição de Lisboa, para, através deles, detectarmos os procedimentos estabelecidos pelos agentes inquisitoriais; apontar, quantitativamente e qualitativamente quais eram as denúncias mais relevantes do ponto de vista do Tribunal; e, identificar, por qual razão algumas queixas não se tornaram processos. / This research aims to analyse how the actions of the Court of the Holy Office in the Portuguese Amazon – Maranhão and Grão-Pará – within the temporal space which extends from 1640 to 1750. The intention is to understand the strategies employed by the Holy Office as a way of spreading its power in a period prior to the Visitation of 1763 during Pombal’s rule within the reality of the colony market by its huge extension and its diverse populations. In this context, we search to identify its agents, as well as the forms used to implement moral and religious discipline in this space and in this society. We will base ourselves, as main source, on the manuscripts of the Promoter of the Inquisition of Lisbon, and through them, try to detect the procedures established by the inquisitorial agents; quantitatively and qualitatively, which were the most relevant complaints from the Court's point of view; and to identify, for which reason some complaints did not turn into processes.
166

Transcriptoma, sítios de ligação para fatores de transcrição e região promotora de cana-de-açúcar / Transcriptome, transcription factors binding sites, and sugarcane promoter region

Oliveira, Mauro de Medeiros 26 September 2018 (has links)
O Brasil tem a maior produção de cana-de-açúcar do mundo. O cultivo de cana-de-açúcar no Brasil está voltado principalmente para a produção de açúcar ou Etanol e nos últimos anos para a produção de bioeletricidade através da utilização da biomassa do bagaço e da palha. Apesar da importância econômica e do potencial sustentável que a cana-de-açúcar apresenta, o genoma de referência para esta cultura ainda não está disponível na literatura. A principal justificativa para isso está na complexidade do mesmo, em especial pela alopoliploidia e autopoliploidia. De fato esta característica é a principal barreira para o desenvolvimento de novas variedades comerciais. Na literatura há diferentes estratégias que visam contribuir com o conhecimento genômico de cana-de-açúcar sendo mais prevalente dados de transcriptoma e pouca informação sobre o processo de regulação gênica. Além disso, diferente do que é observado em outras culturas comerciais, em cana-de-açúcar não há trabalhos associados com a caracterização in silico da região Promotora, assim como na identificação de sítios de ligação para Fatores de Transcrição (TFBSs). Por esta razão, o nosso trabalho foi direcionado para a caracterização in silico de regiões regulatórias em cana-de-açúcar. Para esta tarefa nós realizamos apenas a rotulação de sequências de DNA não codificante que estavam a upstream de cada gene anotado em cana-de-açúcar. Todos os genes foram selecionados de dados de transcriptoma e a sequência de DNA da região Promotora foi isolada do Genespace de cana-de-açúcar SP80-3280 gerado pelo projeto de sequenciamento do genoma de referência do nosso grupo. A rotulação da região regulatória em cana-de-açúcar foi executada em duas subsequências: Core Promoter e Promotor Proximal. Na região Core Promoter nós realizamos a identificação do sítio de inicio de transcrição (TSS), a estimativa do tamanho da região 5\' UTR e a classificação da região Core Promoter em TATA-box ou TATA-less. Todos os processos foram realizados através da ferramenta TSSPlant. A utilização da ferramenta TSSPlant motivou o desenvolvimento de uma nova ferramenta para predição do sinal de TSS que aqui chamamos de TSSFinder. A ferramenta TSSinder apresentou resultados de predição do sinal de TSS superior aos seus pares, além disso esta ferramenta foi bem sucedida em diferentes organismos como Arabidopsis thaliana, Gallus gallus e Saccharomyces cerevisiae. Na região Promotora Proximal nós realizamos a identificação de TFBSs através de duas metodologias: predição de novo e mapeamento de matrizes de TFBS (PSSM). O processo de predição de novo foi realizada por meio de dois modelos: Maximização da expectativa e Gibbs Sampler e esse processo foi executado apenas para o subgrupo de genes co-expressos ou apenas para o conjunto de sequências homeólogas de cada gene de cana-de-açúcar selecionado. Para o restante das sequências foi realizado apenas o mapeamento das matrizes de TFBSs identificadas durante o processo de predição de novo. Em paralelo todos TFBSs identificados no nosso trabalho foram comparados com o banco de TFBS para plantas. Através desse procedimento foi possível estimar qual classe de Fator de Transcrição está interagindo com o TFBS identificado na região Promotora Proximal dos genes Scdr1, ScSuSy, ScPAL. Com este trabalho, nós cobrimos parte da lacuna observada em estudos in silico paras regiões regulatórias de cana-de-açúcar. Além disso, nós aperfeiçoamos o processo de identificação do sinal de TSS para diferentes organismos; inclusive para plantas Dicotiledôneas e Monocotiledôneas. / Brazil has the highest production of sugarcane in the world. Its cultivation in Brazil is aimed at producing of sugar or ethanol and in recent years, biomass for bioenergy from bagasse and straw. Despite the economic importance and the sustainable potential that sugarcane presents, a reference genome for this crop is not yet available in the literature. One justification for this absence lies in the sugarcane genome complexity, allopolyploidy and autopolyploidy. In fact these characteristics are the main barrier for the development of new commercial varieties. In the literature different strategies aimed at contributing to genomic sugarcane mostly on the transcriptome and little information on the process of gene regulation. Furthermore, unlike other commercial crops, sugarcane has no reported in silico characterization of its promoter regions and identification of Transcription Factor binding sites. For this reason, our work was directed to an in silico characterization of regulatory regions in sugarcane. For this task we performed the labeling of non-coding DNA sequences that were upstream of each gene annotated in sugarcane. All genes were using from transcriptome data and the promoter region DNA sequence was isolated from Genespace of the SP80-3280 reference genome obtained of our group. The labeling of the regulatory region in sugarcane was carried out in two subsections: Core Promoter and Proximal Promoter. In the Core Promoter region we performed the identification of the TSS signal, the estimation of the size of the 5\' UTR region and the classification of the Core Promoter region in TATA-box or TATA-less. All processes were performed using the TSSPlant tool. The use of the TSSPlant tool motivated the development of a new tool to predict the TSS signal that we call TSSFinder. The TSSinder tool presented TSS signal prediction results superior to its peers, moreover this tool was successful in different organisms - Arabidopsis thaliana, Gallus gallus and Saccharomyces cerevisiae. In the Proximal Promoter region we performed the identification of TFBSs through two methodologies: de novo prediction and mapping of TFBS matrices (PSSM). The de novo prediction process was performed using two models: Expectancy Maximization and Gibbs Sampler and this process was performed only for subgroups of coexpressed genes or only for the set of homeologues sequences from each sugarcane gene. For the rest of the sequences only the mapping of the matrices of TFBSs identified during the de novo prediction process was conducted. In parallel all TFBSs identified in our work were compared with the TFBS database for plants. Through this procedure it was estimated which class of Transcription Factor is interacting with the TFBS identified in the Proximal Promoter region of the Scdr1, ScSuSy, ScPAL genes.With this work, we cover part of the gap observed in in silico studies for the regulatory region of sugarcane. In addition, we improved the process of identification the TSS signal for different organisms including dicotyledonous and monocotyledonous plants.
167

兩岸公司法制之比較研究 / A Comparative Study on Company Law Between Two Sidea of Taiwan Strait

王文杰, Wang, Wen Chieh Unknown Date (has links)
在公司法上,公司是作為一種制度而存在,它是一種形式定型化行為準則化,運行規範化的企業組織。兩岸均採公司法作為規範市場經濟主體的法律。然兩岸由於政治制度、經濟結構的不同,而存在著各自的特色和相互的差異。公司法制亦然。   本篇論文先就兩岸公司法制個別的發展沿革與變遷背景作歷史觀察;繼之,分別從其法典、法條之形式與實質內容,比較分析兩岸公司法制之體系、制度、規範之異同,及其異同之原因。除了實體法之探究,亦對此分析兩岸公司法制中各個經濟發展與社會環境作用於公司法中的聯繫及影響。尤其是大陸在一九七九年後經濟體制改革到十四大確立社會主義市場經濟體制建立現代化企業的轉換對公司法制的影響及呈現不同風貌。   經由本篇論文所獲致之研究經驗及理解,對於兩岸公司法制之探討將具意義,並以此作為研究兩岸法律體制的基礎與準備。
168

Catalizadores de Rh-soportado y su aplicación en la hidrogenación de crotonaldehído

Krstic, Vesna 19 July 2005 (has links)
Este trabajo ha sido realizado en el contexto de los proyectos de MAT 2002-03808 y MAT 2002-02158, financiados por la Dirección General de Investigación del Ministerio de Ciencia y Tecnología (MCyT). Se han sintetizado y caracterizado catalizadores Rh-soportado (sólo o promovido con Sn) utilizando diferentes tipos de soportes. Como soportes de catalizadores se utilizaron tanto materiales microporosos, silicatos laminares (bentonitas) de distinta procedencia y bentonitas modificadas mediante la introducción de pilares (PILC's) o transformadas en productos zeolíticos; como materiales mesoporosos, MCM-41, con una o dos fuentes de Silicio. Los mencionados catalizadores han sido aplicados en la hidrogenación de crotonaldehído, en fase gaseosa y condiciones suaves, de alto interés tanto académico como industrial en química fina, farmacéutica y alimentaria. Se han analizado y discutido la actividad/selectividad en relación con las diferentes características de los soportes y las distintas condiciones de trabajo como: temperatura de reducción del Rh, temperaturas de reacción, y presencia de estaño como promotor. Se han caracterizado los soportes y catalizadores mediante diferentes técnicas instrumentales UV-Vis, espectroscopia IR, ATG/DTG, DRX, isotermas de adsorción-desorción de N2, quimisorción de O2/H2, quimisorción de NH3, adsorción-desorción de piridina mediante espectroscopia IR-TF, XPS y se utilizó la Cromatografia de gases para la hidrogenación de crotonaldehído. Los resultados obtenidos ponen de manifiesto que tanto las arcillas de partida como las modificadas (con pilares o bien transformada en zeolitas) y materiales MCM-41, han resultado soportes idóneos para la formación de catalizadores heterogéneos de Rh y de Rh promovido con Sn, habiéndose generado, por tanto, nuevos materiales de alto valor añadido para el caso de las arcillas modificadas y nuevos retos de aplicación para los nuevos nanomateriales MCM-41. Así mismo se constata que la adición de Sn como promotor, modifica la conversión a todas las temperaturas de reacción, obteniéndose para todos los catalizadores, mayor selectividad hacia alcohol crotílico que en ausencia de Sn. En resumen, a lo largo de este trabajo se han logrado preparar catalizadores metal soportados utilizando unos nuevos soportes de catalizadores que muestran, generalmente, alta selectividad hacia alcohol crotílico en la hidrogenación de crotonaldehído, en condiciones suaves y a presión atmosférica, condiciones usuales de trabajo en la industria de química fina, farmacéutica y alimentaria, donde time mayor repercusión la aplicación de la reacción estudiada. / This work has been performed within the projects MAT 2002-03808 and MAT 2002-02158, financed by the DGESIC (Dirección General de Enseñanza Superior e Investigación y Ciencia) and CICYT (Comisión de Investigación Científica y Técnica), respectively.An Rh-supported catalyst (alone or promoted with Sn) has been synthesized and characterized using different types of supports. Aluminum silicate (clay) of different origins and clay modified by introduction of pillars (PILC's) or transformed into zeolytic products were used as microporous materials. MCM-41 (with one or two Silicon sources) was used as mesoporous materials. The catalyst has been applied in the hydrogenation of cortonaldehyde in gaseous phase and mild conditions. These have high academic and industrial interest. Activity and selectivity of catalysts have been analyzed at different conditions of work like: temperature of reduction of the Rh, temperatures of reaction and tin presence as promoter.These supports (micro and mesoporous materials) and catalysts have been characterized using different technical instruments: UV-Vis, spectroscopy IR, ATG/DTG, XRD, isotherms of adsorption-desorption of N2, chemisorptions of O2/H2, chemisorptions of NH3, adsorption-desorption of pyridine by DRIFTS, XPS and hydrogenation of crotonaldehyde by Gas Chromatography. The results obtained show that the natural clay material, as modified (with incorporation of pillars or transformed into zeolites), and materials MCM-41, have been good supports to the formation of heterogeneous catalysts of Rh and Rh promoted with Sn, having generated new materials of high value in the case of modified clays and raises new challenges of application for nanomaterials MCM-41. Also observed is that the addition of Sn as promoter was modifying the conversion at all temperatures of reaction, obtaining for all the catalysts greater selectivity to crotyl alcohol than without tin (Sn).In summary, throughout this work, we have been able to prepare and obtain metal supported catalysts using new supports of catalysts that show great selectivity towards crotyl alcohol in the hydrogenation of crotonaldehyde in mild conditions and atmospheric pressure. This is a very important reaction in the production of many pharmaceutical, agrochemical and fragrance compounds, having great repurcussion on the application of the studied reaction and attracting much interest in fundamental research in catalysis.
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Promoter-driven splicing regulation in fission yeast

Moldón Vara, Alberto 17 October 2008 (has links)
The meiotic cell cycle is modified from the mitotic cell cycle by having a premeiotic S phase which leads to high levels of recombination, two rounds of nuclear division with no intervening DNA synthesis, and a reductional pattern of chromosome segregation. Rem1 is a cyclin that is expressed only during meiosis in the fission yeast Schizosaccharomyces pombe. Cells in which rem1 has been deleted show a decreased intragenic meiotic recombination and a delay at the onset of meiosis I. When ectopically expressed in mitotically growing cells, Rem1 induces a G1 arrest followed by severe mitotic catastrophes. Here we show that rem1 expression is regulated at the level of both transcription and splicing, encoding for two proteins with different function depending on the intron retention. We have determined that the regulation of rem1 splicing is not dependent on any transcribed region of the gene. Furthermore, when the rem1 promoter is fused to other intron-containing genes, the chimeras show a meiotic-specific regulation of splicing, exactly as endogenous rem1. This regulation is dependent on two transcription factors of the forkhead family, Mei4 and Fkh2. While Mei4 induces both transcription and splicing of rem1, Fkh2 is responsible for the intron retention of the transcript during vegetative growth and pre-meiotic S phase. / El ciclo meiótico se diferencia del ciclo mitótico por tener una fase S pre-meiótica caracterizada por altos niveles de recombinación, dos rondas de división nuclear sin síntesis de DNA entre las dos y una segregación cromosómica reduccional. Rem1 es una ciclina que sólo se expresa en meiosis en la levadura de fisión Schizosaccharomyces pombe. Celulas con rem1 deleccionado presentan una tasa de recombinación intragénica disminuida y un retraso en el inicio de meiosis I. Cuando se expresa ectópicamente en células creciendo vegetativamente, Rem1 induce un arresto en G1 seguido de catástrofe mitótica. Este trabajo describe que la expresión de rem1 está regulada a nivel de la trascripción y el procesamiento, codificando para dos proteínas con funciones diferentes dependiendo de la retención intrónica.. Hemos determinado que la regulación del splicing de rem1 no depende de ninguna región transcrita del gen. Además, cuando el promotor se fusiona a otros genes que contienen intrones, las quimeras presentan una regulación específica de meiosis como el rem1 endógeno. Esta regulación depende de dos factores de transcripción de la familia Forkhead, Mei4 y Fkh2. Mientras Mei4 induce la transcripción y el splicing de rem1, Fkh2 es responsable de la retención intrónica del tránscrito durante crecimiento vegetativo y fase S pre-meiótica.
170

Exploring the Functional Relevance of Polymorphisms within the CD14 and IRF-1 Gene for Promoter Activity by Haplotype-Specific Chromatin Immunoprecipitation (HaploChIP)

Mertens, Jasmin 19 January 2011 (has links)
No description available.

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