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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.
31

Modelling and analysis of biological systems to obtain biofuels

Montagud Aquino, Arnau 01 October 2012 (has links)
Esta tesis se centra en la construcción y usos de los modelos metabólicos a escala genómica para obtener biocombustibles de manera eficiente, como etanol e hidrógeno. Como organismo objetivo, se ha elegido a la cianobacteria Synechocystis sp. PCC6803. Este organismo ha sido estudiado como una potencial plataforma de producción alimentada por fotones, dada su capacidad de crecer solamente a partir de dióxido de carbono y fotones. Esta tesis versa acerca de los métodos para modelar, analizar, estimar y predecir el comportamiento del metabolismo de las células. La principal meta es extraer conocimiento de los diferentes aspectos biológicos de un organismo con el fin de utilizarlo para un objetivo industrial pertinente. Esta tesis ha sido estructurada en capítulos organizados de acuerdo con las sucesivas tareas que terminan con la construcción de una célula in silico que se comporta, idealmente, como la que está basada en el carbono. Este proceso suele comenzar con los archivos de anotación del genoma y termina con un modelo metabólico a escala genómica capaz de integrar datos -ómicos. El primer objetivo de la presente tesis es la reconstrucción de un modelo del metabolismo de esta cianobacteria que tenga en cuenta todas las reacciones presentes en la misma. Esta reconstrucción tenía que ser lo suficientemente flexible como para permitir el crecimiento en las distintas condiciones ambientales bajo las cuales este organismo crece en la naturaleza, así como permitir la integración de diferentes niveles de información biológica. Una vez que se cumplió este requisito, se pudieron simular variaciones ambientales y estudiar sus efectos desde una perspectiva de sistema. Se han estudiado hasta cinco diferentes condiciones de crecimiento en este modelo metabólico y sus diferencias han sido evaluadas. La siguiente tarea fue definir estrategias de producción para sopesar la viabilidad de este organismo como una plataforma de producción. Se simularon perturbaciones genéticas para e / This thesis is focused on the construction and uses of genome-scale metabolic models to efficiently obtain biofuels, such as ethanol and hydrogen. As a target organism, cyanobacterium Synechocystis sp. PCC6803 was chosen. This organism has been studied as a potential photon-fuelled production platform, for its ability to grow only from carbon dioxide, water and photons. This dissertation verses about methods to model, analyse, estimate and predict the metabolic behaviour of cells. Principal goal is to extract knowledge from the different biological aspects of an organism in order to use it for an industrial relevant objective. This dissertation has been structured in chapters accordingly organized as the successive tasks that end up building an in silico cell that behaves as the carbon-based one. This process usually starts with the genome annotation files and ends up with a genome-scale metabolic model able to integrate ¿omics data. First objective of present thesis is to reconstruct a model of this cyanobacteria¿s metabolism that accounts for all the reactions present in it. This reconstruction had to be flexible enough as to allow growth under the different environmental conditions under which this organism grows in nature as well as to allow the integration of different levels of biological information. Once this requisite was met, environmental variations could be simulated and their effect studied under a system-wide perspective. Up to five different growth conditions were simulated on this metabolic model and differences were evaluated. Following assignment was to define production strategies to weigh this organism¿s viability as a production platform. Genetic perturbations were simulated to design strains with an enhanced production of three industrially-relevant metabolites: succinate, ethanol and hydrogen. Resulting sets of genetic modifications for the overproduction of those metabolites are, thus, proposed. Moreover, functional reactions couplings were studied and weighted to their metabolite production importance. Finally, genome-scale metabolic models allow establishing integrative approaches to include different types of data that help to find regulatory hotspots that can be targets of genetic modification. Such regulatory hubs were identified upon light/dark shifts and general metabolism operational principles inferred. All along this process, blind spots in Synechocystis sp. PCC6803 metabolism, and more importantly, blind spots in our understanding of it, are revealed. Overall, the work presented in this thesis unveils the industrial capabilities of cyanobacterium Synechocystis sp. PCC6803 to evolve interesting metabolites as a clean production platform. / Esta tesis es centra en la construcció i els usos del models metabòlics a escala genòmica per a obtenir eficientment biocombustibles, com etanol i hidrogen. Com a organisme diana, s¿elegí el cianobacteri Synechocystis sp. PCC6803. Aquest organisme ha segut estudiat com una plataforma de producció nodrida per fotons, per la seva habilitat per créixer a partir únicament de diòxid de carboni, aigua i fotons. Aquesta tesi versa sobre mètodes per a modelitzar, analitzar, estimar i predir el comportament metabòlic de cèl¿lules. La principal meta és extreure coneixement del diferents aspectes biològics d¿un organisme de manera que s¿usen per a un objectiu industrial rellevant. La tesi ha segut estructurada en capítols organitzats d¿acord a les successives tasques que acaben construint una cèl¿lula in silico que es comporta, idealment, com la que està basada en carboni. Aquest procés generalment comença amb els arxius de l¿anotació del genoma i acaba amb un model metabòlic a escala genòmica capaç d¿integrar dades ¿òmiques. El primer objectiu de la present tesi és la reconstrucció d¿un model del metabolisme d¿aquest cianobacteri que tinga en compte totes les reaccions que hi estan presents. Esta reconstrucció havia de ser prou flexible com per permetre la simulació del creixement en les diferents condicions ambientals en les quals aquest cianobacteri creix en la natura, així com permetre la integració de diferents nivells d¿informació biològica. Una vegada que aquest requisit fou assolit, es pogueren simular variacions ambientals i estudiar els seus efectes amb una perspectiva de sistema. S¿han simulat fins a cinc condicions de creixement en este model metabòlic i les seves diferències han segut avaluades. La següent tasca fou definir estratègies de producció per a valorar la viabilitat d¿aquest organisme com a plataforma de producció. Es simularen pertorbacions genètiques per al disseny de soques amb producció millorada de metabòlits de rellevància industrial: succinat, etanol i hidrogen. Així, es proposen conjunts de modificacions genètiques per a la sobreproducció d¿aquests metabòlits. També s'han estudiat reaccions acoblades funcionalment i s¿ha ponderat la seva importància en la producció de metabòlits. Finalment, els models metabòlics a escala genòmica permeten establir criteris per integrar diferents tipus de dades que ens ajuden a trobar punts importants de regulació. Eixos centres reguladors, que poden ser objecte de modificacions genètiques, han segut investigats baix canvis dràstics d¿il¿luminació i s¿han inferit principis operacionals del metabolisme. Al llarg d'aquest procés, s¿han revelat punts cecs al metabolisme de Synechocystis sp. PCC6803 i, el més important, punts cecs en la nostra comprensió d'aquest metabolisme. En general, el treball presentat en aquesta tesi dona a conèixer les capacitats industrials del cianobacteri Synechocystis sp. PCC6803 per a produir metabòlits d'interès, tot sent una plataforma de producció neta i sostenible. / Montagud Aquino, A. (2012). Modelling and analysis of biological systems to obtain biofuels [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17319 / Palancia
32

Vývoj pokročilých in-vivo zobrazovacích metod pro neinvazivni studium dynamiky růstu nádorů / Development of advanced in-vivo imaging methods for non-invasive study of tumour growth dynamic

Michalčíková, Tereza January 2019 (has links)
Non-invasive imaging techniques, such as micro-CT or optical imaging, provide valuable information about tumour microstructure, size, volume and growth dynamics. Although histology is an approach capable of describing several of these characteristics, the invasiveness of this analysis remains a disadvantage. The main aim of this work is the methodological development of non-invasive imaging of the dynamics of tumour growth and progression. The preparation of a dual-reporter lentiviral vector enables non-invasive study of tumour growth and dissemination of metastasis. The same dual reporter will also be a part of a second vector designed as a construct for targeting mouse embryonic stem cells with aim to produce corresponding transgenic reporter mouse line. This reporter mouse line can be beneficial for future projects by providing a novel approach for studying the dynamics of tumour growth under various genetic conditions. In addition to optical imaging, this project will also include the use of micro-CT technology which, as a non-invasive approach, has the potential to provide information about the microstructure of tumour tissue in 3D that histology is not able to report.
33

Study of synaptic vesicle cycling during exo- and endocytosis using optical approaches / Studie des Vesikelzyklus während der Exo-und Endozytose mit optischen Methoden

Hua, Yunfeng 23 August 2012 (has links)
No description available.
34

The suitability of estrogen and androgen bioassays for the measurement of endocrine activity in different water matrices

Ngcobo, Silindile January 2017 (has links)
Endocrine disrupting chemicals (EDCs) are ubiquitous in the environment and their presence in water bodies is documented. They discharge into surface water (SW) unmonitored, posing a threat to both aquatic and terrestrial lives. This is a challenge as not all populations have access to treated drinking water (TDW). The EDC contaminated serves as a route of exposure, together with ineffective treatment plants. Given the complexity of the endocrine system, EDCs may mimic or antagonise natural hormones or disrupt their synthesis, metabolism and excretion. The associated health effects include testicular dysgenesis syndrome, metabolic disorders and cancers. Policy and internationally standardised test methods are however sti ll limited. This study therefore aimed to assess the suitability of two assays used for screening estrogenic activity and one for androgenic activity in different water sources. The study consisted of two phases. In phase 1, water sample (tap, surface and treated wastewater) were collected from a catchment area in Pretoria. The samples and a spiked MilliQ laboratory water sample were extracted with solid phase extraction (SPE) and sent to Germany for distribution to participating laboratories. Samples (n=24) from six different countries were received to test for androgenic activity in the MDA-kb2 reporter gene assay. In phase 2, SW and TDW samples were collected from April 2015 until March 2016. The samples were filtered, extracted using SPE and assayed with the YES assay, T47D-KBluc reporter gene assay for estrogenic activity and MDA-kb2 reporter gene assay for androgenic activity. In phase 1, androgenic activity was detected in 4 out of 24 (21%) samples and ranged from 0.23 ± 0.040 ng/L to 0.008 ± 0.001 ng/L DHTEqs. In phase 2, estrogenic activity was detected in 16 out of 24 (67%) SW samples in the T47DKBluc reporter gene assay and ranged from 0.31 ± 0.05 pg/L to 10.51 ± 5.74 pg/L EEqs. It was below the detection limit (dl) in the YES assay. Androgenic activity was detected in 4 out of 24 (17%) SW samples, ranging from 0.0033 ± 0.0050 ng/L to 0.090 ± 0.040 ng/L DHTEqs. Androgenic and estrogenic activity was higher i n pretreatment samples compared to post-treatment in both treatment plants. In phase 1, the MDA-kb2 reporter gene assay was successfully applied to water samples from different sources. Androgenic activity was highest in treated wastewater. In phase 2, treatment plants proved to be effective in removing estrogens detected in the SW samples, as the TDW samples were below the dl. Estrogenic activity is within the ranges reported in other studies. Positive samples were below the 0.7 ng/L proposed trigger value for health risk assessments. Detected androgenic activity was lower in TDW samples compared to the SW samples supplying the two treatment plants indicating that they were both effective in removing the androgenic activity detected. Few studies have reported androgenic activity in tap water. This study strengthens the argument for using a battery of assays when monitoring endocrine activity as EDCs occur at low concentrations in mixtures. / Dissertation (MSc)--University of Pretoria, 2017. / School of Health Systems and Public Health (SHSPH) / MSc / Unrestricted
35

電視新聞播報人專業形象之研究

蘇瑞仁, SU, RUI-REN Unknown Date (has links)
本論文計乙篇,凡分四章,約四萬字。 第一章,緒論。一、闡明本研究之動機及目的旨在調查觀眾對電視新聞播報人條件之 期望,與觀眾如何評定播報人之專業形象。二、檢閱國內外相關文獻。三、界定本研 究各變項之意義及關係。 第二章,研究方法。一、描述本研究調查之樣本。二、選定測量之播報人、設計測量 播報人專業形象之量表及修訂問卷。三、概述調查過程及問卷回收情形。 第三章,資料分析。一、分析播報人條件與受試者背景、收視習慣之關係。二、播報 人專業形象因素分析。三、播報人熟悉度及專業形象之差異。 第四章,結論。一、本研究主要發現。二、研究限制及未來研究建議。
36

我國報業編採人員專業保障問題之研究

韓玉蘭, HAN, YU-LAN Unknown Date (has links)
本論文旨在探討影響新聞人員專業獨立性的因子。研究採問卷調查法,以我國報業編 輯、記者為對象,探討其生活滿意度、對勞動基準法中有關法則之看法、以及對同業 公會之期望等。 一、序論:說明研究動機、研究目的、與研究問題。 二、有關研究與文獻探討。 三、新聞人員專業保障之研究。 四、研究結果之分析。 五、結論與建議。
37

Proměny rozhlasové reportáže v letech 1926 až 1989 / The Transformation of Radio Report between 1926 and 1989

Gillichová, Martina January 2016 (has links)
This thesis focuses on the historical development of radio reportage. The topic includes both political and technological aspects which radio reportage underwent within the Czech environment. All historical periods are described using concrete radio reportages which were broadcast during given terms. The reader can imagine how the radio reporters dealt with first the Germans and then the Soviets. It was the Czech Radio and its reporters who helped Czech people to overcome certain periods in our history. And so in this thesis we can find reportages broadcast during the second world war, right after the end of this war and during the highlights of the communist era - 1968 and 1989. This publication considers the original sources which are kept in the archive of the Czech Radio which is called Archivní a programové fondy Českého rozhlasu. However, this thesis also includes some contributions of contemporary journalists who are interested in history. It should help readers to improve the knowledge of this topics and to organize the development of radio reportage.
38

O autor e o narrador nas tessituras da reportagem / -

Martins, Jaqueline Lemos 22 March 2016 (has links)
Esta tese trata de aspectos da narrativa no jornalismo, mais especificamente na reportagem. Ao assumir a condição inequívoca de autoria no texto, o jornalista abre-se para possibilidade de dar maior complexidade ao ato narrativo, abre-se para articular vozes, visões de mundo e experiências. Nesta complexidade, é possível estabelecer dois sujeitos distintos: o autor (repórter) e o narrador (sujeito elaborado pelo repórter para contar uma história). O embasamento teórico da pesquisa procura articular as noções de complexidade e dialogia (Cremilda Medina) filosofia do diálogo (Martin Buber); ponto de vista (Norman Friedman); experiência e comportamento face a face (Erving Goffman). O autor no jornalismo é um mediador cultural, tem um lugar social demarcado por sua formação profissional e está diretamente ligado ao exercício de um ofício. Já o narrador, é uma criação do autor. É um sujeito que existe para narrar, que adota perspectivas e estratégias para contar uma história, um fato/acontecimento. A constituição do(s) narrador(es) do jornalismo está sob a batuta do autor jornalista. Estabelecemos conexões entre as referências teóricas e a experiência prática. Foram observadas um total de 20 reportagens publicadas/veiculadas em jornal, revista, rádio, televisão e web. Além da observação das reportagens, foram entrevistados os dez repórteres responsáveis por estes textos jornalísticos / This thesis treats aspects of narrative in journalism, more specifically in the report. When assuming an unequivocal condition of authorship in the text, the journalist opens to the possibility of giving more complexity to the narrative act, opens to articulate voices, world views and experiences. In this complexity, it is possible to establish two distinct subjects: the author (reporter) and the narrator (subject developed by the reporter to tell a story). The theoretical basis of the research intends to articulate the notions of complexity and dialogy (Cremilda Medina) ; philosophy of dialogue (Martin Buber); point of view (Norman Friedman); experience and behavior face to face (Erving Goffman). The author in journalism is a cultural mediator and has a social place demarcated by his professional qualification and is directly linked to the exercise of a craft. Yet, the narrator in journalism is a creation of the author. It is a subject that exists to narrate, which adopts perspectives and strategies to tell a story, a fact /event. The constitution of narrator(s) of journalism is under the baton of the author journalist . We established connections between theoretical references and practical experience. It was observed a total of 20 stories published/aired in newspapers, magazines, radio, television and web. In addition to observing the reports, ten reporters responsible for these journalistic texts were interviewed.
39

Reportrars användning av informationsresurser på en svensk dagstidning. / Reporters’ use of information resources at a Swedish daily newspaper.

Ahlin, Jenny January 2007 (has links)
The purpose of this Master’s thesis is to examine the information needs of reporters at a Swedish daily newspaper, and see if they are met by the information resources provided by the newspaper. It examines if there are resources which are not used and why. The examination is based on Henczel’s model for information auditing. The method used is five qualitative interviews with reporters and 25 inquiries are sent out as well. Two interviews with people working with information management on the newspaper are also conducted. The theoretical framework consists of Taylor’s theories about information use environments, Byström’s research on task complexity and how it affects information use, and a discussion about information, knowledge and knowledge management. The result shows that reporters’ information needs are vast and vary a lot depending on what kind of issues they write about. Most of the information needs are met without the information resources provided by the newspaper, although certain resources are considered very important by some of the reporters. There are also unused resources. Reasons for this are that they do not contain the kind of information needed by the reporters, that reporters do not know they exist, or that they are not updated. / Uppsatsnivå: D
40

Genetic modification of human embryonic stem cells for lineage selection, derivation and analyses of human 3rd pharyngeal pouch epithelium like cells and its derivatives

Kaushik, Suresh Kumar January 2017 (has links)
Human pluripotent stem cells (hPSCs) such as, human embryonic stem cells (hES) and human induced pluripotent stem cells (hiPS) are a valuable resource to generate bespoke cell types for a number of therapeutic applications involving cell therapy, drug screening and disease modelling. The overarching goal of this project was to generate a set of transgenic tools by gene targeting and genetic modification of hESCs for applications in stem cell biology such as the in vitro isolation, analyses and derivation of lineage specific cell types. The transgenic tools generated in this study were designed and tested in particular for the human 3rd pharyngeal pouch epithelium (3PPE) like cells and its derivatives, namely the thymus and parathyroid, which are key organs involved in T-cell development and calcium homeostasis respectively. The forkhead transcription factor FOXN1 is considered a master regulator of the development of the thymic epithelium (TEC), the major functional component of the thymic stroma, which is intimately involved in T-cell differentiation. So, to facilitate the prospective isolation of FOXN1 expressing TECs, gene targeting was employed to place a fluorescent reporter and a lineage selection antibiotic resistance gene under the direct control of the endogenous FOXN1 promoter. To date, I have not been able to detect either the fluorescent reporter, or FOXN1 expression using published directed differentiation protocols, but only what can be deemed as precursors expressing the cytokeratin K5 and other markers associated with the development of the thymus and parthyroid from 3PPE. The lack of endogenous FOXN1 activation was observed in both the unmodified parent and the targeted FOXN1 knock-in human ES lines. Further, over-expression of FOXN1 cDNA during the differentiation protocol did not result in the activation of endogenous FOXN1. So, the results evinced in this study could be due to a number of reasons such as, technical issues associated with transference of the published protocols to the cell lines used in this study, differences in hESC lines, and effects of different hESC culture methods and practices. The homeobox gene HOXA3 is expressed in the 3PPE during development. So, a HOXA3 transgenic reporter hESC line could be an invaluable tool for prospective isolation of in vitro derived 3PPE like cells. The reporter was generated by Piggy Bac transposase mediated transposition of a HOXA3 containing Bacterial Artificial Chromsome (BAC) in the FOXN1 knock-in human ES line. To date, this is biggest reported cargo that has been successfully transposed in human ESCs. Moreover, this is the first lineage specific double reporter transgenic hESC line that has been reported for this lineage. This HOXA3 reporter line was then used to isolate and enrich for HOXA3 expressing 3PPE like cells with very high efficiencies during the directed differentiation of hESCs, thus demonstrating the key objective of this transgenic hESC line for this study. In a novel parallel approach, I have conceived, designed and generated transgenic hESCs lines capable of inducible and constitutive over-expression of key transcription factors involved in the development of 3PPE and its derivatives, the thymus and parathyroid. The objective of the said over-expression hESC lines was to interrogate if such a system could elicit morphological and gene expression changes in hESCs following over-expression. By testing the chosen panel of transcription factors in hESCs, I was able to detect cells expressing FOXN1 and GCMB, which are key markers of TECs and PTECs. Further, I have isolated an expandable population of cells expressing markers analogous to their in vivo counterpart found in the 3PPE of a developing mouse embryo around E9.0. The in vivo potency of these in vitro derived 3PPE like cells is yet to be ascertained. Nevertheless, transgenic constructs generated in this experiment could also be tested during future attempts at the differentiation of hESCs to TECs and PTECs, and also used as a basis for future studies involving the direct conversion of patient specific fibroblasts to 3PPE like cells and its derivatives. In summary, several transgenic tools developed in this project, namely the FOXN1 knock-in transgenic hESC line, FOXN1-HOXA3 double transgenic hESC line, over-expression 3PPE transgenes and hESC transgenic lines, and results from the deployment of these tools provide a foundation, from which protocols to generate functional TECs and PTECs can be refined and optimised. These transgenic hESC lines also provide a tractable model, which could be used to interrogate the development of human TECs and PTECs from human 3PPE, and identify hitherto unknown early events in their development in an in vitro reductionist setting.

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