Dissertations / Theses: 'Stem ends'

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Wright, Jacqueline Gilda. "The role of endophytes in citrus stem end rots." Thesis, Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19736654.

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HAGIHARA, Akio, 秋男萩原, Taketo YOKOTA, 岳人横田, Kazuharu OGAWA, and 一治小川. "Allometric Relations in Hinoki (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) Trees." 名古屋大学農学部付属演習林, 1993. http://hdl.handle.net/2237/8694.

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Ali, Enas Hussein [Verfasser]. "Differential Effects of Silibinin on Cardiovascular and Leukocyte Differentiation of Mouse Embryonic Stem Cells / Enas Hussein Ali." Gießen : Universitätsbibliothek, 2018. http://d-nb.info/1174142324/34.

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Tichy, Elisia D. "Double-Strand DNA Break Repair By Homologous Recombination Contributes To The Preservation of Genomic Stability In Mouse Embryonic Stem Cells." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1265989840.

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Naduvile, Veettil Linoj Kumar. "Steam pretreatment as an effective front end for a softwood based biorefinery." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44072.

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For any bioconversion/biorefinery process, the nature of the pretreatment process used has a significant influence on all of the subsequent process steps. Although steam pretreatment has proven effective on agricultural residues and hardwoods, softwoods are considerably more recalcitrant, usually requiring an acid catalyst to ensure effective pretreatment. One of the initial objectives of the work was to assess how effective acid catalysed steam pretreatment would be on a range of softwood substrates as past work had utilized wood chips that were obtained from one tree. It was apparent that similar pretreatment conditions could be used for a range of softwood substrates, resulting in comparable hemicellulose recovery while providing a cellulosic component which could be readily hydrolysed, but at the expense of using high enzyme loadings. To try to enhance cellulose hydrolysis we assessed the role of the various substrate components that are thought to limit hydrolysis. Lignin was shown to restrict hydrolysis at low enzyme loadings (5 – 10 FPU/g glucan), primarily by limiting the accessible cellulose surface area, but also by unproductive binding of the enzymes. To achieve effective hydrolysis at low enzyme loadings, a post-treatment step that removed/modified lignin to enhance the cellulose accessibility was assessed. Steam pretreatment and post-treatment were further optimised to result in a >85% cellulose hydrolysis at an enzyme loading of 10 FPU/g glucan. To try to increase the concentration of final sugars obtained we next evaluated the use of high substrate concentrations. Increased biomass loading during steam pretreatment not only minimised steam and SO₂ consumption, it also resulted in good recovery of the sugars at high concentration. However this was done at the expense of high enzyme loadings. Past work has primarily utilised pulp chips as the feedstock. However, they are unlikely to be used as a commercial bioconversion feedstock. A more likely feedstock, wood pellets were presoaked and steam pretreated. Surprisingly, little hemicellulose loss occurred while the cellulosic rich, water insoluble fraction was readily enzymatically hydrolysed. It was also possible to apply a single steam pretreatment to facilitate both pelletisation and subsequent enzymatic hydrolysis without the need for subsequent steam pretreatment.

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Gosbee, Melinda Jane. "Water deficit stress and the colonisation of mango plant tissue by the stem end rot fungus, Botryospaeria dothidea /." St. Lucia, Qld, 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17490.pdf.

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Jain, Arun K. "Finite depth seepage below flat apron with end cutoffs and a downstream step." Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4939.

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Design curves for uplift pressure at key points, exit gradient factor and seepage discharge factor have been presented in terms of non-dimensional floor profile ratios.; Hydraulic structures with water level differences between upstream and downstream are subjected to seepage in foundation soils. Two sources of weakness are to be guarded against: (1) percolation or seepage may cause under-mining, resulting in the collapse of the whole structure, and (2) the floor of the apron may be forced upwards, owing to the upward pressure of water seeping through pervious soil under the structure. Many earlier failures of hydraulic structures have been reported due to these two reasons. The curves and charts prepared by Khosla, Bose, and Taylor still form the basis for the determination of uplift pressure and exit gradient for weir apron founded on pervious soil of infinite depth. However, in actual practice, the pervious medium may be of finite depth owing to the occurrence of a clay seam or hard strata at shallow depths in the river basin. Also, a general case of weir profile may consist of cutoffs, at the two ends of the weir apron. In addition to the cutoffs, pervious aprons are also provided at the downstream end in the form of (i) inverted filter, and (ii) launching apron. These pervious aprons may have a thickness of 2' to 5'. In order to accommodate this thickness, the bed adjacent to the downstream side of downstream cutoff has to be excavated. This gives rise to the formation of step at the downstream end. Closed form theoretical solutions for the case of finite depth seepage below weir aprons with end cutoffs, with a step at the downstream side are obtained in this research. The parameters studied are : (i) finite depth of pervious medium, (ii) two cut offs at the ends, and (iii) a step at the downstream end. The resulting implicit equations, containing elliptic integrals of first and third kind, have been used to obtain various seepage characteristics. The results have been compared with existing solutions for some known boundary conditions. ID: 030423326; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 220-228). Ph.D. Doctorate Civil, Environmental and Construction Engineering Engineering and Computer Science

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Benson-Greenwald, Tessa M. "The Light at the End of the Tunnel: Temporal Distancing and Academic Attitudes." Miami University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=miami153175957068096.

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Lyons, Anthony J. "International relations theory and the end of the Cold War : a retrospective step forwards." Thesis, University of Essex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340591.

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Carlsson, Reine. "Ett enda steg mellan liv och död : en studie om räddningspersonals tankar när det gäller krisstöd." Thesis, University West, Department of Social and Behavioural Studies, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-1116.

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SILVA, Soraya de Lima e. "Efeitos de ferimento, umidade e temperatura na virulência de espécies de Lasiodiplodia em frutos de manga." Universidade Federal Rural de Pernambuco, 2016. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/6064.

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Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-12-02T12:54:47Z No. of bitstreams: 1 Soraya de Lima e Silva.pdf: 781402 bytes, checksum: 6f6a41f42d5f65201486956ae0b36300 (MD5) Made available in DSpace on 2016-12-02T12:54:47Z (GMT). No. of bitstreams: 1 Soraya de Lima e Silva.pdf: 781402 bytes, checksum: 6f6a41f42d5f65201486956ae0b36300 (MD5) Previous issue date: 2016-02-12 Dieback and stem-end rot, caused by species of Botryosphaeriaceae, are important diseases of mango in the Brazilian Northeast. These diseases limit the production and drastically reduce fruit quality, directly affecting exports. In this study, was investigated the effects of wound, humidity and temperature in virulence of five Lasiodiplodia species prevalent in the orchards of northeastern Brazil (L. hormozganensis, L. iraniensis, L. pseudotheobromae, L. theobromae and L. viticola). Lasiodiplodia hormozganensis, L. pseudotheobromae and L. theobromae did not induce symptoms in non-wounded fruits, but all Lasiodiplodia species induced symptoms in wounded fruits. There were differences between species in relation to virulence levels both in the absence and in the presence of wound. The wound age in fruits influenced the virulence of Lasiodiplodia species of all species has expressed increased virulence when inoculated immediately after the wound, reducing the virulence with increasing wound age. Lasiodiplodia pseudotheobromae was the most sensitive species to the wound age. The high relative humidity length influenced the virulence of the Lasiodiplodia species, with an increase in virulence with the lifting of the period under high humidity. Lasiodiplodia hormozganensis, L. iraniensis and L. theobromae induced symptoms in the absence of high humidity. The virulence of Lasiodiplodia species was significantly influenced by the time interval between the inoculation and beginning of high relative humidity. All species expressed increased virulence when exposed to high relative humidity immediately after inoculation and decreased virulence with increasing time interval to beginning of high humidity. Lasiodiplodia iraniensis and L. viticola were the species most sensitive to the delay in onset of high relative humidity. No Lasiodiplodia species induced symptoms in fruit stored at 5 ° C and only L. pseudotheobromae induced symptoms at 10 ° C. There was no significant difference between species in relation to the optimum temperature for maximum virulence expression, ranging between 29.6 and 31.3 ° C. In most experiments, the increased virulence was demonstrated by L. iraniensis while L. viticola was less virulent. A morte descendente e a podridão peduncular, causadas por espécies de Botryosphaeriaceae, são importantes doenças da mangueira no Nordeste brasileiro. Essas doenças limitam a produção e reduzem drasticamente a qualidade dos frutos, afetando diretamente a exportação. Nesse estudo, foi investigado o efeito de ferimento, umidade e temperatura na virulência de cinco espécies de Lasiodiplodia prevalentes em pomares de mangueira do Nordeste brasileiro (L. hormozganensis, L. iraniensis, L. pseudotheobromae, L. theobromae e L. viticola). Lasiodiplodia hormozganensis, L. pseudotheobromae e L. theobromae não induziram sintomas em frutos sem ferimento, mas todas as espécies de Lasiodiplodia induziram sintomas em frutos feridos. Houve diferença entre as espécies em relação aos níveis de virulência tanto na ausência como na presença de ferimento. A idade do ferimento nos frutos influenciou no nível de virulência das espécies de Lasiodiplodia e todas as espécies expressaram a maior virulência quando inoculadas imediatamente após a realização do ferimento, reduzindo a virulência com a elevação da idade do ferimento. Lasiodiplodia pseudotheobromae foi a espécie mais sensível à idade do ferimento. O tempo de duração da umidade relativa elevada influenciou na virulência das espécies de Lasiodiplodia, havendo um aumento na virulência com a elevação do período em umidade elevada. Lasiodiplodia hormozganensis, L. iraniensis e L. theobromae induziram sintomas na ausência de umidade elevada. A virulência das espécies de Lasiodiplodia foi influenciada significativamente pelo intervalo de tempo entre a inoculação e o início da umidade relativa elevada. Todas as espécies expressaram a maior virulência quando submetidas à umidade relativa elevada imediatamente após a inoculação e reduziram a virulência com o aumento do intervalo de tempo para início da umidade relativa elevada. Lasiodiplodia iraniensis e L. viticola foram as espécies mais sensíveis à demora para início da umidade relativa elevada. Nenhuma espécie de Lasiodiplodia induziu sintomas em frutos armazenados a 5 ºC e somente L. pseudotheobromae induziu sintomas a 10 ºC. Não houve diferença significativa entre as espécies em relação à temperatura ótima para expressão da máxima virulência, que variou entre 29,6 e 31,3 ºC. Na maioria dos experimentos, a maior virulência foi evidenciada por L. iraniensis, enquanto L. viticola foi a menos virulenta.

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Yamauchi, Kazunobu, Mitsuru Ikeda, Yoshiro Suzuki, Masaki Asai, Kazuo Toyama, and Eiichi Hayashi. "Evaluation of the Order Entry System by End Users : A Step to the New Hospital Information System." 名古屋大学医学部, 1994. http://hdl.handle.net/2237/6169.

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13

Saleem, Rashid. "Towards an end-to-end multiband OFDM system analysis." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/towards-an-endtoend-multiband-ofdm-system-analysis(e711f32f-1ac6-4b48-8f4e-58309c0482d3).html.

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Ultra Wideband (UWB) communication has recently drawn considerable attention from academia and industry. This is mainly owing to the ultra high speeds and cognitive features it could offer. The employability of UWB in numerous areas including but not limited to Wireless Personal Area Networks, WPAN's, Body Area Networks, BAN's, radar and medical imaging etc. has opened several avenues of research and development. However, still there is a disagreement on the standardization of UWB. Two contesting radios for UWB are Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) and DS-UWB (Direct Sequence Ultra Wideband). As nearly all of the reported research on UWB hasbeen about a very narrow/specific area of the communication system, this thesis looks at the end-to-end performance of an MB-OFDM approach. The overall aim of this project has been to first focus on three different aspects i.e. interference, antenna and propagation aspects of an MB-OFDM system individually and then present a holistic or an end-to-end system analysis finally. In the first phase of the project the author investigated the performance of MB-OFDM system under the effect of his proposed generic or technology non-specific interference. Avoiding the conventional Gaussian approximation, the author has employed an advanced stochastic method. A total of two approaches have been presented in this phase of the project. The first approach is an indirect one which involves the Moment Generating Functions (MGF's) of the Signal-to-Interference-plus-Noise-Ratio (SINR) and the Probability Density Function (pdf) of the SINR to calculate the Average Probabilities of Error of an MB-OFDM system under the influence of proposed generic interference. This approach assumed a specific two-dimensional Poisson spatial/geometric placement of interferers around the victim MB-OFDM receiver. The second approach is a direct approach and extends the first approach by employing a wider class of generic interference. In the second phase of the work the author designed, simulated, prototyped and tested novel compact monopole planar antennas for UWB application. In this phase of the research, compact antennas for the UWB application are presented. These designs employ low-loss Rogers duroid substrates and are fed by Copla-nar Waveguides. The antennas have a proposed feed-line to the main radiating element transition region. This transition region is formed by a special step-generating function-set called the "Inverse Parabolic Step Sequence" or IPSS. These IPSS-based antennas are simulated, prototyped and then tested in the ane-choic chamber. An empirical approach, aimed to further miniaturize IPSS-based antennas, was also derived in this phase of the project. The empirical approach has been applied to derive the design of a further miniaturized antenna. More-over, an electrical miniaturization limit has been concluded for the IPSS-based antennas. The third phase of the project has investigated the effect of the indoor furnishing on the distribution of the elevation Angle-of-Arrival (AOA) of the rays at the receiver. Previously, constant distributions for the AOA of the rays in the elevation direction had been reported. This phase of the research has proposed that the AOA distribution is not fixed. It is established by the author that the indoor elevation AOA distributions depend on the discrete levels of furnishing. A joint time-angle-furnishing channel model is presented in this research phase. In addition, this phase of the thesis proposes two vectorial or any direction AOA distributions for the UWB indoor environments. Finally, the last phase of this thesis is presented. As stated earlier, the overall aim of the project has been to look at three individual aspects of an MB-OFDM system, initially, and then look at the holistic system, finally. Therefore, this final phase of the research presents an end-to-end MB-OFDM system analysis. The interference analysis of the first phase of the project is revisited to re-calculate the probability of bit error with realistic/measured path loss exponents which have been reported in the existing literature. In this method, Gaussian Quadrature Rule based approximations are computed for the average probability of bit error. Last but not the least, an end-to-end or comprehensive system equation/impulse response is presented. The proposed system equation covers more aspects of an indoor UWB system than reported in the existing literature.

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Lauersdorf, Leslie. "Bone Marrow Transplant Nurses' Attitudes about Caring for Patients Who are Near the End of Life: A Quality Improvement Project." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3199.

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In oncology setting, there is a range of emotions felt by patients and nurses alike such as helplessness, anger, sadness and anxiety; and this is especially the case as patients near the end of life. The literature shows there is an interest in nurses' attitudes toward caring for patients who are near the end of life. This project examines the overall attitude of Bone Marrow Transplant (BMT) nurses' attitudes toward caring for patients who are near the end of life using the Frommelt Attitudes Toward Care of the Dying Scale (FATCOD) and a Demographic Data Sheet. This project investigated the demographic variables including age, gender, ethnicity, religion, Oncology Certified Nurses status, highest degree held, years of nursing experience, years of oncology experience, years of BMT experience, prior continuing education in end of life, and prior experience taking care of a terminally ill patient, to see if they contribute to these differences in attitudes. This was a descriptive project. The sample consisted of a total of 30 BMT nurses, which included 8 men, and 22 women who have worked on the BMT unit for over a year. The mean years of nursing experience was 13.9 (SD=10.10), mean years of oncology nursing experience was 8 (SD=5.80), and mean years of BMT experience was 7.2 (SD=.60). The results of this project indicate that there is a positive relationship between number of years of experience as a nurse and positive attitudes toward caring for patients who are near the end of life. Scores on the FATCOD had a possibility to range from 30-150, with higher scores indicating a more positive attitude toward care of the dying. The scores from this project ranged from 113-148 with a mean of 128.6, indicating an overall positive attitude toward caring for the dying. This project should spur further investigation into attitudes toward caring for patients who are near the end of life. Nurses strive to take the best possible care of their patients and having an understanding of their attitudes will help them recognize areas of strength and weakness. This project supports interventions that are already being done by End of Life (EOL) Committee on the BMT unit at the Moffitt Cancer Center. The EOL committee is helping to create positive attitudes about caring for patients who are near the end of life by both supportive and educational methods.

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PEREIRA, Alba Valéria da Silva. "Sensibilidade a fungicidas e adaptabilidade de Lasiodiplodia theobromae patogênico ao mamão." Universidade Federal Rural de Pernambuco, 2009. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/6396.

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Submitted by (lucia.rodrigues@ufrpe.br) on 2017-02-16T14:00:28Z No. of bitstreams: 1 Alba Valeria da Silva Pereira.pdf: 458155 bytes, checksum: 80e5a16e6ef2e1ee3b97cac4fbc53703 (MD5) Made available in DSpace on 2017-02-16T14:00:28Z (GMT). No. of bitstreams: 1 Alba Valeria da Silva Pereira.pdf: 458155 bytes, checksum: 80e5a16e6ef2e1ee3b97cac4fbc53703 (MD5) Previous issue date: 2009-03-16 Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq Application of fungicide is the main measure of management to stem-end rot and there is no information on the sensitivity and on the fitness costs arising from the reduction in sensitivity of its causal agent, Lasiodiplodia theobromae. One hundred and twenty monosporic isolates collected in producing areas of the Northeast region of Brazil, were divided into six populations. We evaluated the in vitro sensitivity (inhibition of mycelial growth) of the isolates to class the fungicides belonging to two groups: benzimidazoles and sterol demethylation inhibitors (DMIs). We also evaluated the fitness of isolates with different levels of sensitivity the fungicides both in vitro and in vivo (mycelial growth and aggressiveness). The average EC50 for DMIs ranged from 0,141 to 4,054, 0,045 to 0,691 and from 0,001 to 1,529 for tebuconazole, prochloraz and imazalil, respectively. The level of sensitivity to DMIs did not differ among populations. For the benzimidazoles EC50 of 91.6% of the isolates ranged from 0,002 to 0,14 and 0,36 in 1,272 (benomyl and thiabendazole,respectively).The 8.4% isolates, classified as not sensitive (NS) were not inhibited at the highest concentration evaluated (100μg ml of a.i-1). All NS isolates were from the same population. The aggressiveness of NS isolated was lower. A aplicação de fungicida é a principal medida de manejo para podridão peduncular e não há informações sobre a sensibilidade e custos adaptativos decorrentes da redução de sensibilidade do seu agente causal, Lasiodiplodia theobromae. Cento e vinte isolados monospóricos, coletados em áreas produtoras da região Nordeste do Brasil, foram divididos em seis populações. Avaliou-se a sensibilidade in vitro (inibição de crescimento micelial) dos isolados aos fungicidas das classes dos benzimidazois e inibidores da biossíntese de ergosterol (IBEs) e a adaptabilidade in vitro e in vivo (crescimento micelial e agressividade) de isolados com níveis distintos de sensibilidade aos fungicidas testados. A CE50 média para os IBEs variou de 0,141 a 4,054, 0,045 a 0,691 e 0,001 a 1,529 para o tebuconazol, prochloraz e imazalil, respectivamente. O nível de sensibilidade aos IBEs não diferiu entre populações. Para os benzimidazóis a CE50 de 91,6% dos isolados variou de 0,002 a 0,14 e 0,36 a 1,272(benomyl e tiabendazol, respectivamente). Os 8,4%, classificados como não sensíveis (NS), não foram inibidos na maior concentração avaliada (100μg de i.a. ml-1). Todos os isolados NS foram oriundos de uma mesma população. A agressividade dos isolados NS foi menor. Para os IBEs, não foi detectado nenhum custo adaptativo.

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Svensson, Daniel, and Tomas Walander. "Evaluation of an Interphase Element using Explicit Finite Element Analysis." Thesis, University of Skövde, School of Technology and Society, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-3895.

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A research group at University of Skövde has developed an interphase element for implementation in the commercial FE-software Abaqus. The element is using the Tvergaard & Hutchinson cohesive law and is implemented in Abaqus Explicit version 6.7 using the VUEL subroutine. This bachelor degree project is referring to evaluate the interphase element and also highlight problems with the element.The behavior of the interphase element is evaluated in mode I using Double Cantilever Beam (DCB)-specimens and in mode II using End Notch Flexure (ENF)-specimens. The results from the simulations are compared and validated to an analytical solution.FE-simulations performed with the interphase element show very good agreement with theory when using DCB- or ENF-specimens. The only exception is when an ENF-specimen has distorted elements.When using explicit finite element software the critical time step is of great importance for the results of the analyses. If a too long time step is used, the simulation will fail to complete or complete with errors. A feasible equation for predicting the critical time step for the interphase element has been developed by the research group and the reliability of this equation is evaluated.The result from simulations shows an excellent agreement with the equation when the interphase element governs the critical time step. However when the adherends governs the critical time step the equation gives a time step that is too large. A modification of this equation is suggested.

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Janin, Grajcarek. "Genome-wide microhomologies enable precise template-free editing of biologically relevant deletion mutations." Kyoto University, 2020. http://hdl.handle.net/2433/253215.

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Batchelor, Helen R. "Characterisation of store-operated calcium entry in a vascular endothelial cell line and impact on the production of nitric oxide." Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:548a6062-2b2f-46ce-b91a-890561b5edff.

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Store-operated calcium entry (SOCE) is a principal mechanism for extracellular calcium entry in non-excitable cell types, and is primarily facilitated by the calcium- release activated calcium (CRAC) channel; itself comprised of the pore-forming Orai-1 and calcium-sensing Stromal interaction molecule (STIM)-1 proteins. Depletion of endoplasmic reticulum (ER) calcium stores initiates STIM-1 translocation to defined ER-plasma membrane puncta, and subsequent Orai-STIM interaction and opening of Orai. The importance of this mechanism in calcium signalling in diverse tissue types is becoming increasingly clear. The vascular endothelium is a dynamic tissue, involved in the maintenance of vascular homeostasis and haemostasis. Many endothelium-derived bioactive agents, such as endothelin-1, prostaglandins, and the potent vasodilator nitric oxide (NO), are known to be produced via calcium- dependent mechanisms. However, the role of the CRAC channel in the vascular endothelium is poorly defined with little known about downstream targets of calcium influx through CRAC channels. The dysregulation of NO production by endothelial nitric oxide synthase (eNOS) is a major contributory factor in many vascular disease states, yet the calcium channel responsible for eNOS activation has yet to be identified. Within this thesis, I establish the endothelial cell line sEnd.1 as a new model system for studying CRAC channel signalling in the vascular endothelium, defining sEnd.1 SOCE as being CRAC channel-dependent. Inhibition of CRAC channels with an array of inhibitors, and knock-down of STIM-1, both reduced ATP- and TG-induced SOCE. The sEnd.1 model system was subsequently used to identify calcium entry through the CRAC channel as the elusive activation mechanism for eNOS. Through real-time imaging with the fluorescent NO dye DAF-2-DA, we established that NO production is non-linear, with a slow initial increase preceding a faster NO production phase. These kinetics, with a characteristic delay before fast production have, to our knowledge, not previously been reported. The time taken to reach the fast phase of NO production could be manipulated through changes in both local and bulk calcium rises, which indicated roles for both elements of calcium signalling in eNOS activation. eNOS regulation by calcium is complex, occurring not only through direct binding of calcium-calmodulin, but additionally through changing post-translational modifications, which in turn regulate the calcium-dependency of eNOS, such as phosphorylation of Ser1177. We propose that the delay in fast production of NO is due to the time taken to alter eNOS post-translational modifications, which thus remove inhibition on eNOS. Activation of CRAC channels increased phosphorylation of residue Ser1177 via calcium-calmodulin kinase II (CaMKII), with a similar time course to that required to reach the fast phase of NO production. Inhibition of CaMKII increased the time taken to reach fast activation. In conclusion this thesis presents a new model system for investigation of CRAC channel signalling in the endothelium. Furthermore, we clearly identify a critical endothelial pathway as being regulated by CRAC channels, by demonstrating the production of NO in response to both ATP and TG, which stimulate calcium entry through CRAC channels.

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Tutihashi, Rafael Mamoru Carneiro. "Interferência de células-tronco derivadas de tecido adiposo na atividade de produtos finais de glicação avançada em fibroblastos de pacientes diabéticos." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5132/tde-22012016-112145/.

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Feridas nos membros inferiores são a principal causa de hospitalização e morbidade nos pacientes portadores de diabetes mellitus (DM). Atualmente, atribuem-se as complicações tardias do DM ao acúmulo de produtos finais de glicação avançada (AGE) nos diversos órgãos-alvo, incluindo a pele. Já foi demonstrado que a função deficitária dos fibroblastos de diabéticos está relacionada diretamente ao acúmulo de AGEs. Neste cenário, o uso de células-tronco mesenquimais tem ganhado destaque, tendo sido demonstrado, na literatura, que células-tronco derivadas de medula óssea (BMSC) produzem lisozima, um anti-AGE fisiológico. As células-tronco derivadas do tecido adiposo (ADSC) são de fácil captação e apresentam melhor rendimento em cultura celular quando comparadas às BMSC. Neste estudo, investigamos se as ADSC sintetizam lisozima e avaliamos se o produto das ADSC tem a capacidade de diminuir os efeitos deletérios dos AGEs nos fibroblastos. Para esse fim, foram cultivadas ADSC provenientes de lipoaspiração de pacientes hígidos, fibroblastos provenientes de feridas de pacientes diabéticos e fibroblastos provenientes de pacientes hígidos. Os fibroblastos de pacientes diabéticos ou hígidos foram submetidos a três meios de cultura diferentes: normoglicêmico (controle), contendo AGE ou contendo AGE mais o meio de cultura proveniente de ADSC (eluato) e, nesses grupos, foi feito ensaio de migração de fibroblastos. Observamos que, nos meios contendo AGE, não ocorreu migração dos fibroblastos, e na cultura contendo AGE mais eluato, os fibroblastos apresentaram migração semelhante à do grupo controle. Concluímos que as ADSC produzem lisozima e que os produtos sintetizados por essas células têm a capacidade de inibir os efeitos deletérios dos AGEs em fibroblastos in vitro Lower limb ulcers are one of the major causes of morbidity and hospital admission in diabetic patients. Current researches indicate that diabetes mellitus (DM) complications are related to the accumulation in target organs, including the skin of advanced glycation end products (AGEs). It has been shown that cutaneous fibroblasts dysfunction in DM patients is directly dependent on AGE accumulation. In this context, the use of mesenchymal stem cells has been proposed, since bone marrow stem cells (BMSC) produce lysozyme, a physiological anti-AGE enzyme. Adipose tissue derived stem cells (ADSC) are easier to harvest and proliferate faster in cell cultures compared to BMSC. In this study, we investigated whether ADSC are able to produce lysozyme and also the ability of those stem cells to reduce the deleterious effects of AGEs in fibroblasts. ADSC were isolated and cultured from liposuction samples from non diabetic patients; fibroblasts were also isolated and cultured from wounds of diabetic patients and from non diabetic patients\' skin. Fibroblasts were maintained in three different conditions: in normoglycemic culture medium (control), a culture medium containing AGE or a culture medium previously in contact with ADSC for 24 hours (eluate) with addition of AGE. A fibroblast migration assay was performed. There was a lack of fibroblast migration in fibroblast culture with AGE-supplemented medium, whereas fibroblast culture containing ADSC\'s eluate and AGE showed fibroblast migration similar to the control group. Our study demonstrates that ADSC can synthesize lysozyme and we infer that the products of ADSC are able to inhibit in vitro AGE deleterious effects in fibroblas

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Manzini, Bruna Maria 1981. "Avaliação da capacidade de células mesenquimais obtidas de sangue de cordão umbilical, tecido adiposo e de medula óssea humanos na diferenciação em hepatócitos." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312495.

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Orientador: Ângela Cristina Malheiros Luzo Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas Made available in DSpace on 2018-08-24T17:27:32Z (GMT). No. of bitstreams: 1 Manzini_BrunaMaria_M.pdf: 3170870 bytes, checksum: b4d5fa2d17ceaa12512b21b7a473e3bd (MD5) Previous issue date: 2014 Resumo: Introdução: Cirrose e hepatite fulminante ocasionam diminuição severa da função hepática. Recentes avanços em terapia celular podem ser uma alternativa de tratamento. Objetivo desse estudo é analisar se MSCs obtidas de tecido adiposo (TA), sangue de cordão umbilical (SCU) e medula óssea (MO) se diferenciam em hepatócitos funcionais. Materiais e Métodos TA foi obtido de lipoaspiração, SCU do Banco Público de Cordão Umbilical e MO da Unidade de Transplante de Medula Óssea. Termo de Consentimento Livre e Esclarecido foi obtido de todos. TA foi submetido à digestão por colagenase, SCU e MO ao gradiente de Ficoll. As células obtidas foram cultivadas (DMEM meio baixa glicose, SFB) por 3 dias. As células aderentes foram tratadas com tripsina e cultivadas com meio acima e na quarta passagem, caracterizadas por citometria de fluxo, microscopia confocal e diferenciadas para linhagem mesoderrmal para confirmação da diferenciação em MSCs. Atividade da enzima Telomerase (TEA) e cariótipo foram realizados. Diferenciação para hepatócitos: 1,0 x103 MSCs foram semeadas em DMEM, HGF, bFGF, nicotinamida (7 dias), quando receberam meio de maturação (oncostatina, dexametasona e ITS) por 36 dias. A hepatogênese foi analisada por morfologia, funcionalidade (detecção da reserva de glicogênio, marcação PAS), absorção de Indocianina Verde e expressão gênica (PCR-TR dos genes albumina (Alb), Alpha- fetoproteina (AFP), tirosina amino-transferase (TAT) e glutamina sintetase (GS) nos dias 9, 18, 25 e 36). Transplantes: MSCs indiferenciadas e diferenciadas em hepatócitos derivadas de TA e MO infundidas em animais, sacrificados no 7° e 15° dias após transplante, para confirmação e avaliação da regeneração hepática por células humanas através de histopatológico. Resultados: MSCs foram obtidas das três fontes. Análises de telomerase e de cariótipo não demonstraram potencial tumorigênico. MSCs adquiriram morfologia cuboide semelhantes a hepatócitos. Análise funcional efetiva, demonstrando armazenamento de glicogênio e absorção de ICG. Expressão de albumina subiu progressivamente (3.7 no dia 9; 10 no dia 25). AFP inicialmente alta (4.5 dia 9; 5.0 no dia 18), diminuindo depois do dia 18 (3.0 dia 25 e 1.5 dia 36). GS aumentou 3 vezes mais durante processo de diferenciação. TAT foi maior que 6.6 (dia 25 e 36). Anatomopatológico dos transplantes demonstrou que apesar de todas as células conseguirem reverter a lesão, MSCs indiferenciadas foram mais efetivas. Conclusões:. Embora MSCs se diferenciaram em hepatócitos funcionais, devido demora em obter MSCs-SC relativa à diferenciação e expansão, talvez medula óssea e tecido adiposo sejam mais efetivos no processo de regeneração hepática utilizando terapia celular com MSCs Abstract: Introduction: Liver cirrhosis and fulminant hepatites greatly diminishes liver function. Cell therapy could be a new tool for treatment. This study aimed analyze whether mesenchymal stem cells (MSCs) obtained from adipose tissue (AT), umbilical cord blood (UBC) and bone marrow (BM) could differentiate into functional hepatocytes. Material and Method: Adipocyte tissue (AT) was obtained from lipoaspiration, umbilical cord blood from Umbilical Cord Blood Bank and bone marrow (BM) from BM Transplantation Unit donors. All patients and donors signed free informed consent. AT was submitted to collagenase digestion, UCB and BM to Ficoll gradient. Cells were cultured (DMEM low glucose medium, SFB) for 3 days. Detached adherent cells at passage four were characterized as MSCs by flow cytometry, mesodermal lineages differentiation. Telomerase enzyme activity, karyotype analyses discharged tumorigenicity. Hepatocyte differentiation protocol was: DMEM, HGF, bFGF, nicotinamide for 7 days; addition of maturation medium (oncostatin, dexamethasone and ITS) during 36 days. Hepatogenesis was analyzed by morphology and gene expression (RT-PCR) of albumin, AF, TAT and GS genes on day 9, 18, 25 and 36. Functionality confirmed by glycogen storage detection, indocyanine green( ICG) absorption and animal experiment performed with transplantation of undifferentiated AT and BM MSCs and hepatocyte-like cells derived from AT and BM-MSCs into BALB/NOD mice submitted to fulminant hepatitis by CCl4 intraperitoneal injection. Animals were sacrificed at 7 and 15 days post transplantation to perform anatomohistopathological analyses. Results: All MSCs acquired cuboid form as hepatocyte-like cells, stored glycogen and absorbed ICG demonstrating functionality. Albumin expression gradually increased (3.7 on day 9 , 10 on 25 ). AFP expression was high at the beginning (4.5 day 9 ; 5.0 on day 18 ) , decreasing after day 18 ( 3.0 and 1.5 on day 25 day 36 ). GS expression increased 3 times during the differentiation process. TAT expression was greater than 6.6 on day 25 and 36. Animal experiments showed that undifferentiated MSCs (U-MSCs) and derivate hepatocyte ¿like cells regenerate the injured liver, but in different degrees. U-MSCs promoted better liver regeneration. Conclusion: MSCs differentiated into funcional hepatocytes, U-MSCs promoted better regeneration at animal experiments, and might be a useful tool for regenerative medicine in liver injuries improving cell therapy in this field Mestrado Fisiopatologia Cirúrgica Mestra em Ciências

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Shikwambana, Kingsly. "Effect of harvest time, post-harvest storage and ripening temperature on fruit quality of reed avocado cultivar." Thesis, University of Limpopo, 2016. http://hdl.handle.net/10386/2049.

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Thesis (M. Sc. (Agriculture, Horticulture)) --University of Limpopo, 2016 ‘Reed’ avocado is a late season cultivar introduced to South Africa from California. The cultivar has shown good adaptation and produces quality fruit with export potential. Its pre-harvest adaptation and production aspects have been researched and documented. However, the effect of harvest time, post-harvest storage and ripening temperature has not been comprehensively studied on this newly introduced ‘Reed’ avocado cultivar. Therefore, the aim of this work was to investigate the effect of different harvest time, post-harvest storage and ripening temperature on the quality of late season ‘Reed’ avocado fruit. Matured ‘Reed’ avocado fruit were harvested based on moisture content indexing in December (2015) and January (2016). The experiment was carried out in a factorial, arranged in a completely randomised design (CRD) with three replicates. Treatment factors were: 2 x harvest time (mid-and late), 2 x post-harvest storage (2.0 and 5.5°C), 3 x ripening temperature (16, 21 and 25°C) and 5 x ripening day (0, 2, 4, 6 and 8). Fruit were stored at 2.0 and 5.5°C for 28 days, thereafter, ripened at 16, 21 and 25°C until fully ripe. During ripening, fruit were evaluated for weight loss, skin colour, firmness, respiration rate, physiological and pathological disorders. Mid-harvest fruit had higher moisture content when compared with late harvest fruit. However, harvest time, post-harvest storage, ripening temperature and ripening time (days) significantly influenced fruit weight loss, firmness, respiration rate, ripening percentage of ‘Reed’ avocado fruit during ripening. Moreover, fruit firmness decreased faster at higher temperatures (25 and 21°C) with fruit ripening within 4 and 6 days, respectively. In addition, ripening at a lower temperature (16°C) was slower with fruit fully ripened within 8 days after withdrawal from cold storage at both harvest times. ‘Reed’ avocado fruit respiration rate followed a climacteric pattern, however, significantly higher rate at higher temperature (25°C) when compared with lower temperature (16°C) after withdrawal from cold storage during both harvest times. Interestingly, mid-harvest fruit showed high electrolyte damage after withdrawal from 2.0°C when compared with late harvest fruit at the same temperature. Furthermore, mid-harvest fruit stored at 2.0ºC and ripened at 21°C showed higher chilling injury when compared with fruit ripened at 16 and 25°C. High electrolyte leakage positively correlated (R2 = 0.242) with high chilling damage for xiv mid-harvest fruit stored 5.5°C. Treatment factors had a significant effect (P < 0.05) on lightness (L *) and hue angle (h ) but no significant effect (P > 0.05) on chroma (C *) and eye colour of ‘Reed’ avocado fruit during ripening, irrespective of harvest time. Overall results showed a visual change in ‘Reed’ avocado skin colour, with eye colour changing from green to bright yellow. Furthermore, late harvest fruit showed high post-harvest pathological diseases after removal from high temperature (5.5°C) when compared with mid-harvest fruit stored at low storage temperature (2.0°C). Ripening at a higher temperature (21 and 25°C) resulted in higher incidence of stem-end rot and body rot when compared with lower temperature (16°C) for both harvest times. Late harvest fruit showed a higher incidence of vascular browning at higher ripening temperatures (21 and 25°C) when compared with lower temperature (16°C) after withdrawal from cold storage. Moreover, overall results showed that harvest time, post-harvest storage and the ripening temperature had a profound influence on the quality of ‘Reed’ avocado fruit. In conclusion, ‘Reed’ avocado fruit can be harvested during mid- or late season and stored at recommended low temperature (2.0ºC); and thereafter, ripened at either 16 or 21ºC. In addition, future studies should focus on identifying pre-harvest practices that promote higher post-harvest fruit quality for ‘Reed’ avocado fruit under South African production environment. Keywords: ‘Reed’ avocado fruit; firmness; electrolyte leakage; respiration rate; stem-end rot; body rot; vascular browning

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Mokrani, Sofiane. "Maintenance de la stabilité chromosomique des cellules souches neurales murines au cours du développement et après un stress génotoxique aiguë ou chronique Impaired brain development and behavior of Xlf null mice linked to chromosome instability-induced premature neurogenesis Higher Chromosome Stability in Mouse Embryonic Neural Stem and Progenitor Cells than in Fibroblasts in Response to Acute or Chronic Genotoxic Stress." Thesis, Institut polytechnique de Paris, 2019. http://www.theses.fr/2019IPPAX010.

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Une exposition prénatale aux radiations ionisantes est associée au développement de pathologies neurodéveloppementales liées à l’induction de dommages à l’ADN dans les cellules souches et progéniteurs neuraux (CSPN). Ainsi, la stabilité génétique des CSPN est cruciale pour le développement et l’homéostasie du cerveau. Cependant, des altérations génomiques au niveau des CSPN au cours du développement pourraient promouvoir la diversité neuronale. XLF est un composant de la voie de réparation d’ADN par NHEJ (pour Non-Homologous End-Joining). Nous avons montré une augmentation de l’instabilité des CSPN dans le cerveau embryonnaire des souris Xlf-/- qui pourrait perturber la neurogenèse au cours du développement, et ainsi être responsable d’altérations comportementales identifiées chez ces souris à l’âge adulte. A l’aide d’approches cytogénétiques, nous avons comparés la stabilité chromosomique des CSPN et des fibroblastes embryonnaires murins (MEF) exposés à un stress génotoxique aigue (irradiation γ) ou chronique (incorporation de thymidine tritiée dans l’ADN). Nos résultats démontrent que les CSPN maintiennent leur intégrité génétique de façon plus efficace que les MEF. En effet, les CSPN semblent avoir de meilleures capacités de réparation des dommages à l’ADN que les MEF, ce qui leur permet de développer une réponse adaptative à un stress génotoxique chronique. Cette réponse adaptative implique XLF et agit conjointement avec les points de contrôle du cycle cellulaire et l'apoptose pour préserver la stabilité du génome et éliminer les cellules endommagées. L’ensemble de nos résultats apporte la démonstration d’une réponse robuste aux dommages de l'ADN dans les CSPN et souligne l'importance de XLF lors du développement du cerveau Prenatal exposure to ionizing radiation has been associated with many neurodevelopmental disorders due to the DNA damage induced in neural stem and progenitors cells (NSPC). Thus, genetic stability of NSPC is crucial for brain development and homeostasis. Nevertheless, genomic alterations occurring during development in NSPC may have a potential impact on the physiological neuronal diversity. XLF is a component of the NHEJ (Non-Homologous End-Joining) repair pathway. Here, we show that NSPC from Xlf-/- embryos exhibit increased chromosome instability, leading to premature neurogenesis and consequently neurobehavioral disorders. Using cytogenetic approaches, we compared the chromosome stability of mouse embryonic NSPC and fibroblasts (MEF) exposed to acute (γ-irradiation) or chronic (incorporation of tritiated thymidine into DNA) genotoxic stress. Our results demonstrate the higher capacity of NSPC as compared to MEF to maintain their genomic integrity. We evidenced that NSPC have more efficient DNA repair activity than MEF, allowing them to develop an adaptive response to chronic genotoxic stress. This adaptive response involves XLF and acts together with apoptosis and cell cycle checkpoints to preserve the stability of the genome and to eliminate damaged cells. Altogether, our results provide new insights into the robust DNA damage response in NSPC and highlight the importance of Xlf during brain development

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Alliegro, Fernando Canola 1981. "Análise histopatológica convencional versus cortes seriados em esvaziamentos cervicais de pacientes com Carcinoma Espinocelular (CEC) de cavidade oral e orofaringe cN0 = mudança de status cervical e correlação com sobrevida = Increasing neck staging with step-serial sectioning of neck dissection specimens for oral end oropharyngeal SCC patients." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312536.

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Orientadores: Carlos Takahiro Chone, Agricio Nubiato Crespo Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas Made available in DSpace on 2018-08-26T23:06:19Z (GMT). No. of bitstreams: 1 Alliegro_FernandoCanola_M.pdf: 11261621 bytes, checksum: 619f82b9bd6eaeef9951fee3cd054674 (MD5) Previous issue date: 2015 Resumo: Objetivo. Avaliar a mudança no estadiamento cervical de pacientes com carcinoma espino celular (CEC) de cavidade oral e orofaringe, após alteração na padronização da análise anátomo-patológica dos linfonodos de espécimes cirúrgicos de esvaziamentos cervicais, clinicamente livres de metástases (cN0), com cortes seriados de todos os linfonodos. Materiais e Métodos. Estudo retrospectivo com 21 pacientes previamente classificados como cN0 submetidos a cirurgia para exérese do tumor primário e esvaziamento cervical eletivo. Realizou-se inicialmente a revisão das laminas originais e, posteriormente, cortes seriados com 5 µm de espessura e nova análise das lâminas. Para avaliar o impacto da mudança na sobrevida foi realizada análise de Kaplan-Meier (IC 95%). Resultados. Após a avaliação convencional, 14 pacientes foram classificados como pN0, isto é, patologicamente livres de metástases cervicais, e sete (33%) como pN+, ou seja, patologicamente acometidos. A análise com cortes seriados detectou outros três pacientes com acometimento linfonodal, previamente classificados como pN0 e 1 previamente estadiado como N1 mudou para N2b com 10 pacintes pN+ (48%). Houve aumento de 43% (3/7) no número de pacientes com acometimento linfonodal e 19% de aumento no estadiamento linfonodal após a nova padronização anátomo-patológica, porém sem impacto na sobrevida (p=0,554). Conclusão. Análise com cortes seriados de linfonodos de esvaziamento cervicais permitiu um aumento de 14% no número de pescoços com metastases ocultas e de 19% no estadiamento cervical inicial frente à técnica convencional Abstract: Objective. Asses the change in neck staging in patients with squamous cell carcinoma (SCC) of oral cavity and oropharynx after new methodology for histopathological analysis of lymph nodes of surgical specimens from neck dissections, with step serial sections of all harvested lymph nodes, in clinically neck negative patients (cN0). It was also studied the impact of this changes on survival. Materials and methods. Retrospective study with 21 patients previously classified as cN0 undergoing surgery for excision of the primary tumor and elective neck dissection. Initially was held to revise the original pathology slides and, subsequently, step-serial sectioning with 5 µm thick and re-examination of the slides. In order to assess the impact of change in disease-free survival was held Kaplan-Meier analysis (IC 95%). Results. After conventional evaluation, 14 patients were found to be without lymphatic metastases (pN0) and seven (33%) were affected (pN+). The analysis with step serial section has detected three other patients with lymphatic metastases, previously classified as pN0, and one patient previously as N1 increased to N2b with 10 pN(+) cases (48%). There was an increase of 43% in patients with lymph node metastases and 19% of increase in neck staging after the new histopathological standardization, but without impact on survival (p = 0.554). Conclusion. Analysis of lymph nodes in surgical specimens of neck dissections with step-serial sectioning allowed an increase of 43% of necks with occult metastases and increase of neck staging in 19% when compared to conventional technique Mestrado Otorrinolaringologia Mestre em Ciências Médicas

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Kocaba, Viridiana. "Tissue engineering pour la reconstruction cornéenne." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1078.

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En France, les dysfonctions endothéliales représentent environ la moitié des indications de greffes de cornée réalisées chaque année. Cependant, les problématiques liées à la pénurie de greffon, aux difficultés des techniques chirurgicales de greffes endothéliales ainsi qu’aux risques d’échec ou de rejet de greffe poussent les chercheurs à développer de nouvelles thérapies moins invasives et plus efficaces. La thérapie cellulaire cornéenne endothéliale est une des voies de recherche actuellement explorées dont le but est de s’affranchir des aléas de la greffe de cornée. La cornée humaine est un tissu idéal pour la thérapie cellulaire. Grâce à ses caractéristiques d’organe à la fois avasculaire et immunitairement privilégié, les cellules transplantées sont ainsi bien mieux tolérées par rapport aux autres tissus et organes vascularisés. Les avancées dans le domaine des cellules souches, de l'ingénierie, particulièrement avec l’arrivée des greffes de cellules souches épithéliales pour le traitement des pathologies sévères de la surface oculaire, ont suscité un intérêt massif afin d’adapter ces techniques aux cellules endothéliales In France, around half of all corneal keratoplasties are performed to treat corneal endothelial dysfunction each year. However, the use of endothelial keratoplasty is limited by the technical difficulty of the procedure, a shortage of available grafts, and the potential for graft failure or rejection. These limitations are driving researchers to develop new, less invasive, and more effective therapies. Corneal endothelial cell therapy is being explored as a potential therapeutic measure, to avoid the uncertainty associated with grafting. The human cornea is an ideal tissue for cell therapy as owing to its avascular characteristics, transplanted cells are better tolerated compared with other vascularized tissues and organs. Advances in the field of stem-cell engineering, particularly the development of corneal epithelial stem cell therapy for the treatment of severe diseases of the ocular surface, have aroused a massive interest in adapting cell-therapy techniques to corneal endothelial cells

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Lassalle, Damien. "Les pore forming toxin chez les Lophotrochozoaires : exemple des organismes Biomphalaria glabrata/ Schistosoma mansoni A New Assessment of Thioester-Containing Proteins Diversity of the Freshwater Snail Biomphalaria glabrata Cholesterol-TEG addition at the 5’end of siRNA allows significant increase of its uptake by hemocytes from Biomphalaria glabrata, the schistosomiasis vector snail. Under review in PeeJ. Schistosoma mansoni lysine specific demethylase (SmLSD1) is a druggable target involved in parasite survival, oviposition and stem cell proliferation." Thesis, Perpignan, 2020. https://theses-public.univ-perp.fr/2020PERP0036.pdf.

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La bilharziose est une maladie touchant 230 millions de personnes dans le monde (source OMS). Cette parasitose est provoquée par le schistosome, un vers plat parasite nommé Schistosoma mansoni. Avant de pénétrer dans l’organisme humain par la peau, ce parasite se développe chez un escargot d’eau douce, Biomphalaria glabrata, qui lui sert d’hôte intermédiaire. Nous avons dans ce contexte identifié et étudié deux protéines appartenant à la famille des pore formingtoxins (PFTs), que nous avons appelé Biomphalysine et Glabralysine. Les PFTs sont des effecteurs très connus dans le monde procaryote pour favoriser leurs pathogénicités. Ces protéines sont produites de manière soluble par les organismes, pour se fixer et s’agréger sur les membranes cellulaires cible, ce qui a pour conséquence de créer un pore lytique. Cette super famille de protéine se divise en deux sous familles, alpha et beta, classées en fonction de la modalité de formation du pore. Des études antérieures ont permis de caractériser pour la première fois des ß-PFT chez le mollusque Biomphalaria glabrata, ces protéines ont montré un rôle clef dans l’immunité du mollusque, notamment la capacité de lier au parasite et de le tuer. Cette découverte a pu ouvrir le champ à l’investigation de protéines similaire chez le mollusque et chez le parasite avec lequel il interagie. Ce projet de thèse a pour objectif, au travers d’étude génomique, transcriptomique et protéomique de caractériser et de comprendre la fonction des différentes « pore forming toxins » présentes chez le mollusque Biomphalaria glabrata et chez le parasite Schistosoma mansoni. Grace à des données collectées avant et durant le projet de thèse, nous avons pu caractériser 23 variants apparentés à la famille des Biomphalysines. Cette famille multigénique sans intron, semble avoir été acquise au travers de transfert horizontal de gênes. Par homologie avec les biomphalysines, nous avons pu caractériser 5 gènes codants pour un deuxième groupe de ß-PFT chez Biomphalaria glabrata, que nous avons appelé les Glabralysines. Ces protéines constituent une famille à part entière, proche des toxines cry de Bacillus thuringiensis, et qui d’un point de vue structural partage des homologies avec la Biomphalysine. Elles sont en effet, produites par les cellules immunitaires du mollusque et induites lors de l’infection par le parasite Schistosoma mansoni. Finalement, nous avons aussipu découvrir deux gènes codants pour des toxines, nommées Schistolysines, de la famille des ß-PFT chez le parasite Schistosoma mansoni. Ces protéines semblent être répandues chez les parasites et jouer des rôles essentiels dans leur développement, la reproduction et peut être la nutrition. Nous montrons que ces protéines sont exclusivement retrouvées au stade adulte du parasite et devraient donc jouer un rôle dans l’interaction avec l’hôte humain ou dans l’implantation ou l’exploitation de cet hôte. Ces différentes approches, dans le contexte de l’interaction entre l’hôte et son parasite permettront potentiellement d’identifier de nouvelles stratégies de lutte ou de contrôle de la maladie sur le terrain. Les résultats générés dans ce travail pourront permettre également d’étudier le rôle de ces molécules dans l’interaction avec d’autres pathogènes ou leur lien avec d’autres pathologies et plus particulièrement leur utilisation dans le développement de nouveaux traitements contre le cancer par exemple Bilharzia is a disease affecting 230 million people worldwide (source WHO). This parasitosis is caused by schistosome, a parasitic flatworm, and in particular by Schistosoma mansoni, responsible for intestinal bilharzia in Africa and tropical America. Before entering the human body through the skin, this parasite develops in a freshwater snail, Biomphalaria glabrata, which serves as an intermediate host. In this context, we have identified and studied two proteins belonging to the pore forming toxins (PFTs) family, which we have called Biomphalysin and Glabralysin. Pore forming toxins are effectors well known in the prokaryotic world to promote their pathogenicity. These proteins are produced in a soluble way by organisms, to bind and aggregate on the target cell membranes, resulting in the creation of a lytic pore. This protein superfamily is divided into two families, alpha and beta, classified according to the pore formation modality. Previous studies have characterized for the first time §-PFTs in the mollusc Biomphalaria glabrata, these proteins have shown a key role in the immunity of the mollusc, including the ability to bind and kill the parasite. This discovery may have opened the field to the investigation of similar proteins in the mollusc and in the parasite with which it interacts. This thesis project aims, through genomic, transcriptomic and proteomic studies, to characterize and understand the function of different "pore forming toxins" present in the mollusc Biomphalaria glabrata and in the parasite Schistosoma mansoni. Thanks to data collected before and during the thesis project, we were able to characterize 23 variants related to the Biomphalysin family. This multigenic family, without intron, seems to have been acquired through horizontal gene transfer. By homology with the Biomphalysins, we were able to characterize 5 genes coding for a second group of §-PFT in Biomphalaria glabrata, which we called Glabralysins. These proteins constitute a family in their own right, close to the Cry toxins of Bacillus thuringiensis, and which structurally share homologies with the Biomphalysin. They are indeed produced by the immune cells of the mollusc and induced during the infection by the parasite Schistosoma mansoni. Finally, we were also able to discover two genes coding for toxins, called Schistolysins, of the §-PFT family in the parasite Schistosoma mansoni. These proteins seem to be widespread in parasites and play essential roles in their development, in reproduction and hypothetically in nutrition. We show that these proteins are found exclusively in the adult stage of the parasite and should therefore play a role in the interaction with the human host or in the implantation or exploitation of this host. These different approaches, in the context of the interaction between the host and its parasite, will potentially lead to the identification of new strategies for the control or management of the disease in the field. The results generated in this work could also allow to study the role of these molecules in the interaction with other pathogens or their link with other pathologies and more particularly their use in the development of new cancer treatments for example

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Masci, Lorella. "Cristallochimie du fer dans les chlorites métamorphiques : approche analytique multiéchelle, expérimentale, et implications pétrologiques." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS256.

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Les chlorites sont des phyllosilicates ayant la particularité de cristalliser sur une large gamme de conditions de pression et température, et dans une variété de roches et d’environnements géologiques pouvant aller du contexte diagénétique au contexte métamorphique de type schiste bleu à amphibolitique. La composition des chlorites est sensible à leur température de cristallisation, et avec leur présence récurrente au sein des paragénèses, celles-ci sont couramment utilisées pour l’estimation des conditions thermobarométriques par les pétrologues. Cependant la plupart des modèles thermobarométriques actuels ne permettent pas d’estimer de manière fiable des températures au sein de l’ensemble des compositions des chlorites. Les modèles thermodynamiques en particulier ne prennent pas en compte ou sous-estiment l’état d’oxydation du fer dans les chlorites qui peut être sous forme Fe2+ ou Fe3+. Ce travail de thèse a ainsi pour objectif d’apporter de nouvelles données cristallochimiques sur un large panel de chlorites ayant incorporé du fer trivalent de compositions et contextes variés, tout en répondant aux questions sur : (1) la quantité de Fe3+ qui peut être incorporée dans les chlorites, (2) les substitutions cationiques permettant l’incorporation du Fe3+ dans les chlorites et leurs pôles purs associés, (3) la localisation du Fe3+ et des autres cations dans les sites cristallographiques des chlorites et enfin, (4) sur le lien éventuel entre le Fe3+ dans les chlorites et les conditions thermodynamiques du milieu que sont la pression, température, et la fugacité en oxygène à l’échelle du cristal et du minéral. Ce travail de thèse utilise différentes méthodes de mesure du Fe3+/FeTOT ; la spectroscopie d’absorption du fer au seuil K (K XANES), et la spectroscopie par perte d’énergie des électrons (EELS) couplées à l’utilisation de la microsonde électronique. Ce volet analytique est complété par des analyses de diffraction des rayons X. L’approche utilisée repose sur l’étude de chlorites naturelles échantillonnées pour leur représentativité du domaine de composition, ainsi que sur des chlorites synthétisées expérimentalement sous pression, température, et fugacité en oxygène contrôlées. Une nouvelle base de données cristallochimiques sur les chlorites ferriques constitue l’apport principal de ce travail, et a permis en particulier de mettre en évidence les substitutions contrôlant l’incorporation du Fe3+ dans la structure. Ainsi la substitution di-trioctaédrique 3R2+ = 2Fe3+ + _ et l’échange Al = Fe3+ semblent expliquer le domaine de composition des chlorites ferriques jusqu’à Fe3+ ∼ 1.5 p.f.u., permettant de définir un ou plusieurs pôles purs de type ferri-sudoite en plus d’un pôle ferrique non lacunaire et magnésien, dans les chlorites naturelles et synthétiques. Mais l’analyse de l’oxygène dans les chlorites les plus ferriques montrent un déficit de protons interprété comme lié à l’oxydation du fer divalent, tel que : Fe2+ + H+ = Fe3+, mettant en évidence un composant "oxychlorite" à base anionique O12(OH)6. Une implication importante est que la présence de lacunes et la substitution di-trioctaédrique précédemment révélées sont largement un artefact de normalisation sur la base anionique O10(OH)8. A l’échelle du minéral la distribution du rapport Fe3+/FeTOT dans les chlorites montre des variations pouvant atteindre jusqu’à ∼ 30 %, sur une échelle de la centaine à dizaine de nanomètres. Cette hétérogénéité se retrouve également à l’échelle du micromètre mais n’est pas corrélée à la distribution du FeTOT et des autres éléments majeurs dans la lame. Enfin en plus de confirmer les substitutions des chlorites naturelles, les synthèses de chlorites ont permis d’identifier un probable contrôle de la fugacité en oxygène sur le rapport Fe3+/FeTOT mais pas sur la quantité de Fe3+ incorporée, indépendamment de la composition de départ Chorite is a phyllosilicate crystallizing in a wide range of pressure and temperature conditions, among a diversity of rocks : from diagenesis to metamorphic conditions, typically in greenschist facies but also in blueschist and amphibolite facies. Chlorite is useful for metamorphic petrology as a geothermometer, as its composition is sensitive to the temperature of crystallization and chlorite is commonly found within mineral assemblages. Chlorite shows many solid solutions, among which Fe may be incorporated in large proportions in divalent (Fe2+) and/or trivalent (Fe3+) state. Unfortunately current models for geothermometry on chlorite either neglect Fe3+ or require evaluating the thermodynamic properties of Fe3+-rich chlorite for increased accuracy. This study aims at providing new crystal-chemistry data on ferric chlorite from a wide range of composition and origin, and to answer the following questions : (1) how much Fe3+ may be incorporated in chlorite ? (2) what are the cationic substitutions and end-members for Fe3+ incorporation ? (3) how is Fe3+ distributed within the chlorite structure ? and (4) what are the dependencies between Fe3+ in chlorite and the pressure-temperature conditions, and oxygen fugacity, at crystal and mineral scales ? This work investigates the speciation of iron in chlorite with different techniques; X-ray absorption near-edge spectroscopy at the Fe-K edge (K XANES), and electron energy-loss spectroscopy (EELS) combined with electron microprobe major element analyzes. X-ray diffraction investigation brings structural information on the structure of ferric chlorite. This analytical strategy is focused on chlorite from natural rock samples and experimental syntheses made at fixed pressure and temperature, and under buffered oxygen fugacity. A new database on ferric chlorite crystal-chemistry is the major output of this work, which highlights substitutions involving Fe3+. A Fe3+ -rich, vacant endmember is required to account for the di-trioctahedral substitution, and a magnesian end-member with 1 Fe3+ replacing Al for the homovalent Al - Fe3+ substitution. These results are observed in natural specimens and confirmed by experimental synthsesis of ferric chlorite. In addition, chlorite with Fe3+ > 1.5 p.f.u. shows systematic deviation from the ideal O10(OH)8 anionic basis, where proton deficit has been inferred from indirect measurements of H+ content. These results are consistent with the existence of an "oxychlorite" group within the classification of phyllosilicates. At mineral scale, the variations of the oxidation state take place at nanoscale and are unrelated to variations in the amount of Fe. Chlorite crystallized via experimental synthesis shows similar features. These results explain the poor success of geothermometry on some iron-rich chlorite, and allow us to propose improved cation distribution algorithms for geo thermometry. Our study paves the way for future experimental synthesis focused on oxychlorite

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Pic, Axel. "Numerical and experimental investigations of self-heating phenomena in 3D Hybrid Bonding imaging technologies." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI054.

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Dans cette thèse, les phénomènes d’auto-échauffement ont été étudié pour guider la conception de circuits intégrés 3D de nouvelle génération. Grâce à des études expérimentales et numériques, la dissipation thermique dans des imageurs 3D par collage hybride a été analysée et l’impact de l’augmentation de température résultante a été évalué. Premièrement, afin de développer des modèles précis, les propriétés thermiques des matériaux utilisés dans les circuits intégrés ont dû être déterminées. Différents films minces diélectriques impliquant des oxydes, des nitrures et des composés low-k ont été étudiés. Pour ce faire, la microscopie thermique à sonde locale (SThM) et la méthode électrothermique 3ω, sensibles à la conductivité thermique effective faible et élevée, ont été mises en œuvre. Dans un deuxième temps, des modèles éléments finis de circuits intégrés 3D ont été développés. Une méthode numérique nécessitant homogénéisations et approches multi-échelles a été proposée pour surmonter des grands rapports de forme inhérents à la microélectronique. La procédure numérique a été validée en comparant les calculs et les mesures expérimentales effectuées par SThM, la thermométrie résistive et la microscopie infrarouge sur une puce de test par collage hybride simplifiée. Il a été montré que la dissipation de chaleur est principalement limitée par la conductance du puit thermique ainsi que les pertes par l'air. Enfin, des études numériques et expérimentales ont été réalisées sur des imageurs 3D par collage hybride fonctionnels. Le champ de température a été mesuré par SThM et comparé aux calculs par éléments finis à la surface de la matrice. Les résultats numériques ont montré que la température de la surface des pixels est égale à celle du Front-End-Of-Line de l’imageur. L'influence de l'échauffement sur les performances optiques de l'imageur a été déduite de cette analyse. Cette étude a permis également d'évaluer les différentes méthodes numériques et expérimentales pour la caractérisation de la dissipation de chaleur en microélectronique In this PhD thesis, self-heating phenomena are studied for guiding the design of next-generation 3D Integrated Circuits (ICs). By means of experimental and numerical investigations, associated heat dissipation in 3D Hybrid Bonding imagers is analyzed and the impact of the resulting temperature rise is evaluated. First, in order to develop accurate models, the thermal properties of materials used in ICs are to be determined. Different dielectric thin films involving oxides, nitrides, and low-k compounds are investigated. To do so, Scanning Thermal Microscopy (SThM) and the 3ω electrothermal method, sensitive to low and large effective thermal conductivity, are implemented. In a second step, finiteelement models of 3D ICs are developed. A numerical method involving homogenization and a multiscale approach is proposed to overcome the large aspect ratios inherent in microelectronics. The numerical procedure is validated by comparing calculations and experimental measurements performed with SThM, resistive thermometry and infrared microscopy on a simplified Hybrid Bonding test chip. It is shown that heat dissipation is mainly limited by the heat sink conductance and the losses through air. Finally, numerical and experimental studies are performed on fully-functional 3D Hybrid Bonding imagers. The temperature field is measured with SThM and compared with finite-element computations at the die surface. The numerical results show that the temperature of the pixel surface is equal to that of the imager Front-End-Of-Line. The influence of the temperature rise on the optical performance of the imager is deduced from the analysis. The study also allows assessing the various numerical and experimental methods for characterizing heat dissipation in microelectronics

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Drouin, Érika Véronique. "L'utilisation des cellules souches embryonnaires à des fins thérapeutiques." Thèse, 2003. http://hdl.handle.net/1866/2381.

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La découverte des cellules souches embryonnaires et de leur immense potentiel thérapeutique a fait naître de grands espoirs. De nouvelles thérapies révolutionnaires pour traiter certaines des maladies les plus graves dont souffre l'humanité sont désormais envisageables. Le traitement de la vie à son stade le plus précoce est mis en cause. Le statut juridique reconnu au foetus et à l'embryon humain a des répercussions directes sur le domaine de la recherche et sur leur utilisation à des fins thérapeutiques. Nous avons examiné l'état du droit canadien quant au statut juridique du foetus et de l'embryon. De cette étude, nous avons constaté l'incertitude qui prévaut au Canada quant à leur statut. Par la suite, nous avons étudié les différentes normes canadiennes établies pour encadrer l'utilisation des cellules souches embryonnaires à des fins thérapeutiques et nous les avons analysées et comparées pour faire ressortir leurs similitudes et leurs différences. II est ressorti de notre analyse que les textes canadiens se rejoignent généralement sur l'essentiel et qu'il y a eu peu de changements de 1993 à aujourd'hui, en regard des activités de recherche interdites au Canada. Puis, nous avons examiné les systèmes normatifs applicables à ces recherches à l'étranger, soit aux États-Unis et en GrandeBretagne. Nous avons effectué une analyse comparative des trois systèmes normatifs étudiés, en évaluant différents paramètres communs à ces systèmes. Il est ressorti de cette analyse, que la Grande-Bretagne est le pays le plus libéral relativement à ces domaines de recherche, que les États-Unis sont les plus conservateurs sur ces questions et que le Canada se situe entre les deux. The embryonic stem cells discovery and the immense therapeutic potential glven to them has created big hopes in the world of today. The appearance of new revolutionary therapies to treat sorne of the most serious known diseases are now conceivable. However, the treatment of life to its earliest stage is questionned. The legal status recognized to the foetus and the embryo has, in fact, a direct effect to the research area and industry as weil as to its therapeutic use. Therefore, we have examined and studied the CUITent canadian law with respect to the legal status of the foetus and embryo. Following this study, we have noticed the uncertainty that prevails in Canada concerning the said legal status. Afierwards, we have examined ail the different canadian norms and regulations already established regarding the use of embryonic stem cells for therapeutic ends. We also did the comparaison between those norms and regulations so as to see their differences and similarities. It appears from our analysis that ail the canadian litterature generally treat the subject in the same way and that there have been few changes from 1993 up until now with respect to the forbidden researchs activities in Canada. We also have analysed the foreign law standards and regulations in United States and Great Britain concerning those forbidden researchs activities. We did the exercise of comparing the state of the law in these three countries with different parameters. It emerges from that that Great Britain is the most liberal country, United States being the most conservative and Canada being in between them. "Mémoire présenté à la Faculté des études supérieures en vue de l'obtention du grade de Maîtrise en droit (L.L.M.) Option recherche"

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Obier, Nadine. "Defining the end of pluripotency in mouse embryonic stem cells." Doctoral thesis, 2010. https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-53722.

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Stammzellen mit ihrer besonderen Fähigkeit sich selbst zu erneuern und zu differenzieren stellen einen faszinierenden Zelltyp für Grundlagenforschung und angewandte Wissenschaften dar. Pluripotente embryonale Stammzellen (ES Zellen), die aus Zellen der inneren Zellmasse von Präimplantationsembryonen etabliert werden, können ekto-, meso- und endodermale Zelltypen sowie Keimzellen hervorbringen. Im Gegensatz dazu sind multipotente adulte Stammzellen in ihrem Entwicklungspotential eingeschränkt, sie differenzieren sich zu allen Zelltypen ihres Gewebes. Zum Beispiel hämatopoetische Stammzellen (HSZs), die sich in Blut-bildenden Geweben wie dem Knochenmark befinden, vermögen sich in alle Blutzellen zu differenzieren. Während der Differenzierung von Stammzellen ändert sich nicht deren Genom, sondern ihre epigenetische Regulation. Durch epigenetische Mechanismen werden Zelltypen mit verschiedensten Phänotypen und Funktionen generiert. Für Stammzelltherapien ist ein tieferes Verständnis des Zusammenhangs von Epigenom und zellulärer Funktion wichtig. Im Rahmen dieser Dissertation war es mein Ziel, differenzierende Stammzellkulturen auf ihre Genexpression, ihre Chromatinregulation und ihr Differenzierungspotiential hin zu analysieren. Um Histonmodifikationen, die einen möglichen Mechanismus epigenetischer Regulation darstellen, global untersuchen zu können, sind zunächst, durchusszytometrische Protokolle etabliert worden, die die Analyse einzelner Zellen ermöglichen sollten. Mit dieser Methode konnten reduzierte Levels von Histonazetylierung in differenzierten ES Zellen gezeigt werden. Im Gegensatz dazu beobachtete ich vergleichbare Levels von Histonazetylierung in unreifen und reifen Knochenmarkzellen. Zusätzlich untersuchte ich die Wirkung des Histondeazetylase-Inhibitors (HDI) Trichostatin A (TSA) auf Knochenmarkzellkulturen, in denen auch HSZs enhalten sind. Nach Behandlung mit TSA erhöhte sich der Anteil von Zellen mit in vitro und in vivo hämatopoetischer Aktivität, während vor allem differenzierte Zellen in Apoptose gingen. Außerdem wurde der Verlust der Pluripotenz in differenzierenden ES Zellkulturen untersucht. Marker-basierte Analysen und funktionelle Tests wurden mit ES Zellen durchgeführt, die kurzfristig in vitro differenziert wurden. Es stellte sich heraus, dass nach funktionellen Gesichtspunkten die Pluripotenz bereits nach 2 Tagen Differenzierung deutlich reduziert war, beurteilt anhand der Fähigkeit Kolonien zu bilden, embryoide Körperchen (EK) zu formieren und zu kontrahierenden Herzmuskelzelltypen zu differenzieren. Im Gegensatz dazu verringerte sich die Expression von Pluripotenzmarkern erst zu späteren Zeitpunkten. Ich habe weiterhin beobachten können, dass die Wahl des Differenzierungssystems (Aggregations-EK, klonale EKs oder als adhärente Einzelzellschicht) einen Einfluss auf den Fortschritt und die Homogenität der Differenzierung hatte. Um das Ende der Pluripotenz genauer zu untersuchen, wurden differenzierte ES Zellen zurück in ES Zellkulturbedingungen gebracht. Die Ergebnisse deuten an, dass 3 Tage differenzierte ES Zellen einen Punkt überschritten haben, an dem eine Rückkehr zur Pluripotenz allein durch Kulturbedingungen noch möglich ist. Durch die Behandlung mit HDIs starben selektiv differenzierte ES Zellen. Des Weiteren war es Ziel dieser Arbeit, den Einuss von EED - einer essentiellen Untereinheit des Histon-methylierenden Polycomb repressive complex 2 (PRC2) - auf das Chromatin und die Funktion von ES Zellen hin zu analysieren. ES Zellen ohne EED wiesen neben dem bereits bekannten Verlust der Trimethylierung von Histon 3 an Lysin 27 (H3K27me3), global reduzierte H3K9me3 Levels sowie erhöhte Histonazetylierung auf. Trotz typischer ES Zell-Morphologie und normaler Expression von Pluripotenzgenen, besaßen EED knockout (KO)ES Zellen eine veränderte Organisation der Heterochromatinstruktur im Zellkern, eine verlangsamte Chromatinmobilität und Probleme bei der Differenzierung. Zusammenfassend gewähren meine Daten Einblick in die epigenetische Regulation von Stammzellen. Im Besonderen konnte ich zeigen, dass die Behandlung mit HDIs für differenzierende Knochenmarkzellen und differenzierende ES Zellen nachteilig war und zu deren selektivem Zelltod führte. Die hier durchgeführten Analysen ergaben, dass ES Zellen nach 3 Tagen Differenzierung das Ende der Pluripotenz erreicht hatten. Schließlich zeigten die Versuche mit EED KO ES Zellen, dass sie sich zwar selbst erneuerten und morphologisch identisch mit wildtypischen ES Zellen waren, jedoch Defekte bei der Differenzierung besaßen. Dies deutet darauf hin, dass EED nicht nur für undifferenzierte ES Zellen wichtig ist, sondern auch während der Differenzierung von Bedeutung ist Stem cells with the particular potential to self renew and to differentiate into multiple cell lineages are fascinating cell types for basic and applied research. Pluripotent embryonic stem (ES) cells are derived from the inner cell mass (ICM) of preimplantation embryos. Upon differentiation ES cells can give rise to cells of ecto-, meso- and endoderm including germ cells. In contrast, multipotent adult stem cells are more restricted in their differentiation outcomes,they differentiate into cells of their tissue of origin. For example, hematopoietic stem cells (HSCs) that reside in hemogenic tissues such as the bone marrow (BM) differentiate into hemato-/lymphoid cell lineages. Upon differentiation of stem cells not the genome, but the epigenetic regulation changes. Differentiation-associated epigenetic changes generate cell types with distinct phenotypes and functions. For stem cell-based therapies it is important to deeper understand the relation between epigenome and cellular function. In the scope of this thesis I aimed to analyze cultures of differentiating stem cells with respect to gene expression, chromatin regulation and differentiation potential. For the analysis of global histone modification levels, which represent one mechanism for epigenetic regulation, fow cytometric protocols were established that allow single cell measurements. By applying this methodology decreased histone acetylation levels were shown in differentiated ES cell populations. In contrast, comparable histone acetylation levels were observed in differentiated and undifferentiated BM cells. In addition, I investigated effects of the histone deacetylase (HDAC) inhibitor trichostatin A (TSA) on murine BM cells, comprising also HSCs. Upon TSA treatment the frequency of cells with in vitro and in vivo hematopoietic activity was increased, while lineage committed cells underwent apoptosis. Next, the loss of pluripotency was assessed in differentiating ES cell cultures. Using short-term in vitro differentiation protocols marker-based analyses and functional assays were performed.Functionally pluripotency was diminished after 2 days of differentiation as assessed by colony formation, embryoid body (EB) formation and cardiomyogenic differentiation approaches. In contrast, pluripotency marker expression was reduced at later time points. Further, the application of distinct differentiation systems (aggregation EB, clonal EB or monolayer (ML) culture) had an impact on the progression and homogeneity of differentiation cultures. To further study the end of pluripotency, differentiated ES cells were placed under ES cell culture conditions. The data suggest that 3 days differentiated ES cells had passed a point of no return and failed to regain Oct4-eGFP expression and that HDAC inhibitor treatment selectively killed differentiated ES cells. Finally, I aimed to study the effect of EED - a core subunit of the histone methylating Polycomb repressive complex 2 (PRC2) - on ES cell chromatin and function. ES cells lacking EED showed loss of histone H3 lysine 27 trimethylation (H3K27me3) accompanied by increased histone acetylation and reduced H3K9me3 levels. Despite typical ES cell morphology and pluripotency marker expression, EED knockout (KO) ES cells exhibited altered nuclear heterochromatin organization, delayed chromatin mobility and a failure in proper differentiation. Conclusively, my data provide insights into the epigenetic regulation of stem cells. Particularly, the results suggest that HDAC inhibitor treatment was detrimental for differentiated BM as well as for differentiated ES cells and that ES cells after 3 days of differentiation had lost pluripotency. Further, the data demonstrate that EED KO ES cells self renewed, exhibited morphology and pluripotency marker expression similar to wild type ES cells, but failed to differentiate. This indicates an important role of EED not only for undifferentiated but also for differentiating ES cells

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Obier, Nadine [Verfasser]. "Defining the end of pluripotency in mouse embryonic stem cells = Studien zum Ende der Pluripotenz in emrbyonalen Stammzellen der Maus / submitted by Nadine Obier." 2010. http://d-nb.info/100978935X/34.

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Li, Shr-Ling, and 李世玲. "Identification and physiological characterization and control of stem end rot of mango." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/12042711900360653153.

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碩士 國立高雄師範大學 生物科學研究所 91 Abstract Stem-end rot of mango is one of the most common and destructive diseases of cultivated mango worldwide. Recently, the disease has resulted in the poor quality of ripe fruit of mango and lower market prices in Taiwan. According to observation, symptoms at the stem end as fruit ripen usually included water-soaked tissue, quickly darken and circular lesions. Two categories fungi were isolated consistently from symptomatic fruits and from sample exhibiting twig dieback. One of the fungi produced alpha and beta spores in pycnidia when cultured on potato dextrose agar. Spore measurements were taken from 50 for each isolate obtained from fruits or twig dieback. Based on spores size, with alpha spores (3.75-7.75 x 1.25-2 μm ) and beta spores (17.5-25.0 x 0.5-1 μm ), the fungus was identified as Phomopsis mangiferae Ahmad. The other fungus was designed as isolate 0509, and observed on PDA media to produce abundant, cotton white to fluffy mycelia. Conidia are initially hyaline, aseptate and ellipsoid. Mature conidia (12.8-24.2 x 6.9-14.2 μm ) are uniseptate and brown walled. The isolate 0509 was identified as Botryodiplodia theobromae (Pat.). Comparison of the identities of rDNA ITS-full gene sequence between P. mangiferae and genus of Phomopsis in NCBI reached 98 % ; and B. theobromae as well as genus of Botryodiplodia in NCBI reached 96%. Most mango cultivars in Taiwan were susceptible to P. mangiferae and to B. theobromae. Fruit symptoms were observed after one week on wounded but not for nonwounded inoculated fruits. diseased tissue. Physiological tests for two pathogens of stem-end rot of mango were performed to the requirement of nutrient and environmental factors. The optimal temperatares of the mycelial growth for P. mangiferae and B. theobromae were 28~32 ℃ and 20 to 24 ℃, respectively. however, for on PDA media. The optimal pH values for both pathogens were between pH 5 and 9. Of the carbon sources, lactose resulted in the highest linear growth for B. theobromae and P. mangiferae, respect ;vely. carbon sources. Of the nitrogen sources, NH4HPO4 and casein were the best for B. theobromae and P. mangiferae. Nine commercial fungicides were evaluated on PDA for their abilities to inhibit mycelial growth of two pathogens. 62.5%Fludioxonil + Cyprodinil WG at 1:1500 dilution、74.1% Metalaxyl＋Copper Oxychloride at 1:1000 dilution、80% Fosetyl-Al＋Oxine-Copper WP at 1:800 dilution、37% Flusilazol EC at 1:5000 dilution and 43%Kasugamycin at 1:1000 dilution were highly effective against two pathogens, and Bacillus subtilis Y1336 and Streptomyces candidus Y21007-2 only inhibited the mycelial growth of both pathogens. .

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Lin, Ming-Fu, and 林銘福. "Design and Analysis of Elliptical Ball-End-Mill and Step-End-Mill." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/11882175700168761449.

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博士 國立成功大學 機械工程學系碩博士班 94 ABSTRACT End mills are widely used in various machining. Its geometry of cutting edges have critical effects on the milling processes and product qualities. Especially, helical ball-end-mills are in the widest use to create a variety of curved surfaces. However, the geometry of a helix ball-end-mill is complicated. Therefore, its manufacturing or re-sharpening usually needs high-skilled technician and precision tool-grinding machine. To overcome this difficulty, an unique geometry of ball-end-mill without helix flute is introduced by Aoyama, et. al. and modeled theoretically in this paper. It takes only one simple step for grinding or re-sharpening. Its elliptical cutting edges enable the end mill to meet the demanding requirements in terms of easy manufacturing, thereby enabling high-accuracy and high-performance cutting for machine parts. Its rake angle, clearance angle, wedge angle and cutting edge angle are then investigated according to International Standard Organization (ISO) by using homogeneous transformation matrices. To validate the developed algorithms, an elliptic ball-end-mill is designed and produced on an universal tool grinding machine. This design eliminates the needs of precision tool-grinding machine in manufacturing or/and re-sharpening processes, and enables excellent tool accuracy to be attained. In section IV of the study, a geometric shape of the step ball end mill is established by using differential geometric method; section V covers the normal vector of the face and flank of the cutting curve of the step ball end mill. In section IV, the required position and posture of the wheel for grinding the face and flank of the mill is determined, and since the cutting tools shape discussed in this article is from a unique generatrix, it takes the transformation of RPY matrix to get the required degrees of freedom of the position and posture as well as the matrix of the grinding wheel and the step ball end mill. Based on the matrix of the position and shape of the end mill deduced in section VI, it is concluded that the six-axis CNC machine tool of Ewag Corporation, Switzerland, is used to grind the step ball end mill. The main reference source of mathematical model of such six-axis CNC machine tool is the article uses the results to infer the NC program of mills with different forms of generatrix end. The step ball end mill is taken as an example.

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Demoz, Besrat Tesfagiorgis. "Alternative application methods of antagonists to avocado flowers to control stem-end rot pathogens." Diss., 2005. http://hdl.handle.net/2263/28456.

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Biological pre- and postharvest disease control strategies depend on successful colonisation and survival of the introduced antagonists on the infection court. Effective and economical applications involve targeting the antagonists where they are critically needed i.e. the infection court. Honeybee dispersal is one method of antagonist application to such specific sites. In view of this, an in vitro experiment was conducted to investigate attachment, colonisation and survival of Bacillus subtilis on avocado flowers. Scanning electron microscopy studies showed that the bacterium could attach and colonise avocado flower surfaces. It can also survive on the flowers for longer periods of time. In vivo mode of action of the antagonist against stem-end rot (SER) pathogens was also studied where results showed lysis and degradation of hyphae and conidia. However, no viable colonies were retrieved from bee antagonist dispersal under field conditions. Bee antagonist dissemination was compared with antagonist and fungicide spray applications in terms of SER control and the added effect on other diseases such as Cercospora spot and anthracnose. Spray applications of the antagonist were more effective in reducing the incidence of SER than bee dissemination. Integrated sprays of the antagonist and fungicides significantly reduced the incidence of both pre- and postharvest diseases. The identity of Dothiorella aromatica, one of the most important SER pathogens, was investigated at a molecular level. RAPD techniques using the discriminatory OPC02 primer successfully separated isolates into three groups based on banding profiles. A further study using RFLP identified the pathogen as a Botryosphaeria spp. The most dominant specie was B. parva followed by B. rhodina. Further studies should focus on assessing the distribution of these pathogens within avocado-growing regions of South Africa. Dissertation (MSc (Plant Pathology))--University of Pretoria, 2006. Microbiology and Plant Pathology unrestricted

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Lin, Yu-Ling, and 林育玲. "Mesenchymal stem cells ameliorate atherosclerotic lesions via restoring eNOS activity and relaxation response in endothelial cells." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/43826311211647901986.

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碩士 國立陽明大學 臨床醫學研究所 101 Objectives The purpose of the study was to evaluate the effect of mesenchymal stem cells (MSC) to treat atherosclerosis in apoE−/− mice. Background Transplantation of MSCs has been proved to be beneficial in treating myocardial infarction (MI), but the ability of MSCs to ameliorate pre-clinical atherosclerosis remains unknown. Methods In vitro, oxLD-induced human umbilical vein endothelial cells (HUVEC) damage was used. The Akt/eNOs expression was analyzed by western blot. Nitric oxide(NO) production was analyzed by Griess Assay. PCR array analysis was used to search for the possible factor in the effect of MSC. In vivo, groups with MSC, MSC treated with anti-macrophage inflammatory protein 2 (MIP-2) Ab, MIP-2 alone and PBS were studied in apoE −/− mice. Endothelial function was determined by tension recording test. Akt/eNOs expression was quantified by Immunohistochemistry. Results MSC reversed the inhibitory effect of oxLDL on Akt pathway, thereby restoring eNOS activity and ameliorating endothelial dysfunction in apoE−/− mice. The improvement of endothelial dysfunction by MSCs was significantly blocked in the group of MSCs treated with anti-MIP-2 Ab and improved by MIP-2 injection alone. Among the mitogen-activated protein kinases(MAPK) family, the level of phosphorylated P38 was increased in MSCs upon exposure to oxLDL. The effect of MSC p38 knockdown on oxLDL-exposure MSC also significantly inhibited IL-8 expression. Conclusions: MSC transplantation improved the endothelial function and plaque formation in apoE−/− mice. IL-8 and the P38 MAPK signaling pathway are involved in the protective effect of MSCs. The study contributes to elucidate the mechanisms in the use of MSCs for atherosclerosis.

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Chen, Pei-Hsien, and 陳佩賢. "Identification and physiological characterization and control of stem-end rot of papaya（Carica papaya L.）." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/88815650060445557025.

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碩士 國立高雄師範大學 生物科學研究所 91 Abstract Stem-end rot is one of postharvest diseases on papaya in Taiwan .The fungus was known to infect stem, petiole and fruit. This disease often start on stem of fruit, so it called stem-end rot. The symptoms begin at the stylar-end with circular water-soaked spots on the fruit, soften and then rot and mummify the entire fruit. The colonies of the pathogen cultured on PDA plates were white and gradually turned to gray, fluffily with abundant aerial mycelium. Conidia are initially hyaline and unicellular, subovoid to ellipsoidal with a granular content. Mature conidia are two-celled, cinnamon to light brown in color and often with longitudinal striations. According to the morphological characteristics of the pathogen, the causal agent was identified as Botryodiplodia theobromae. Pat. Comparison the identity of rDNA ITS-full gene sequence between B. theobromae and genus of Botryodiplodia in NCBI reached 99 % , they are confirmed to be of the same genus. The pathogens grow best in PDA culture at temperatures between 25~30 ℃, 30 ℃is the optimum temperature for growth and 25 ℃ is the optimum temperature for sporulation. Carbon sources for better growth are dextrose, fructose and sucrose. Nitrogen sources are potassium nitrites, sodium nitrites, glycine and urea. The mycelial growths and sporulation of B. theobromae were stimulated when cultured under light. Of the various media tested, the best for mycelial growth were potato dextrose agar, maltose extract agar and V8 juice agar. The optimal water potential was between -4.5~ -18.1 bars. B. theorbrame can grow at pH values ranging from 4 to 10, there is no significant difference in growing. The optimal temperature for conidial germination was 25~30 ℃, spore germination over 90 % after 4 hours. Fungicides were evaluated on PDA for their abilities to inhibit mycelial growth of the pathogen, 62.5 % Fludioxonil + Cyprodinil, 37 % Flusilazol, 25.9 % Tebuconazole, 25 % Prochloraz and 23.7 % Iprodione had better inhibition on pathogen growth. The IC50 are below 10 g(a.i)/ml. Among biological agents test, two isolates of Trichoderma (FT-010, FT-023) and one isolate of Streptomyces (SS31) had 100 % inhibition on B. theorbrame . The result of two biological agents already available in market Bacillus subtilis Y1336 (Bio-aid) and Streptomyces candidus Y21007-2 (Bio-bac) showed that when Y1336 were diluted to 100, 1000, and 10000 times, the percentage of inhibition were 70.7 %, 69 %, and 59.4 % ,respectively, and Y21007-2 was diluted to 100 times, the percentage of inhibition is 74.6 %. After spraying the diluted chemical and biological agents on the inflected fruits, 62.5 % Fludioxonil +Cyprodinil at 1 : 1500 dilution, 37 % Flusilazol at 1 : 10000 dilution and two biological agents Y1336 (Bio-aid) at dilution 1 : 600 and Y21007-2 (Bio-bac) at dilution 1 : 800 proved to be effective.

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Chen, Sheng-Wen, and 陳聖文. "High-speed Optical Front-end Circuits and STDM Switch with Optical Interconnect Interface." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/51325042304404822476.

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碩士 國立清華大學 電子工程研究所 101 With the increasing speed of data transmission and processing, in order to solve the non-ideal effects of conventional electrical interconnect, O/E interface is proposed to be used in chip-to-chip or intra-chip level transmission, known as the optical interconnect (OI). This thesis including five chapters focuses on designing the high-speed optical front-end blocks for OI applications. The first four chapters describe optical transceiver front-end circuits, and the optical front-end blocks are combined with a 4×4 high-speed switch to achieve a fully-integrated high-speed switch with OI interface in chapter 5.

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Huang, C. Y., and 黃朝鈺. "Force Model and Stability Analysis for Step-Over Cutting in Ball-End Mill." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/27377482200159154953.

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碩士 國立成功大學 機械工程學系 89 Force Model and Stability Analysis for Step-Over Cutting in Ball-End Mill Abstract This thesis presents an analytic force model for the slot, half-slot and step-over milling of the ball end milling processes. The analytic force model is established as the convolution of three process functions, namely tooth sequence function, coordinate transformation function and the elementary cutting function. Each of the three functions represents and describes the respective geometry and mechanics aspects of the milling process. Modeling for the step-over milling is more complicated than the other two processes and an approximated method is presented to simplify the force model. Experiment results from machining tests verify the accuracy of these analytic models. Based on the analytic force models, the stability of ball end milling process is further analyzed. A two dimensional system model is constructed including the tool/work dynamics, cutter geometry and cutting conditions of the ball end milling process. Stability limit in terms of axial and radial depths of cut and chatter frequency are analyzed and predicted as functions of system parameters including depth of cut, structure stiffness and damping property. This stability model is validated by comparing the theoretical predictions with published results.

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Castanho, Francisco, and Maksim Defer. "MTU aero engines ag: full steam ahead for MTU as end-customers drive demand for engines and maintenance." Master's thesis, 2019. http://hdl.handle.net/10362/73200.

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Hamza, Syed Muhammad Farrukh. "Shear-enhanced permeability and poroelastic deformation in unconsolidated sands." Thesis, 2012. http://hdl.handle.net/2152/ETD-UT-2012-08-6353.

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Heavy oil production depends on the understanding of mechanical and flow properties of unconsolidated or weakly consolidated sands under different loading paths and boundary conditions. Reconstituted bitumen-free Athabasca oil-sands samples were used to investigate the geomechanics of a steam injection process such as the Steam Assisted Gravity Drainage (SAGD). Four stress paths have been studied in this work: triaxial compression, radial extension, pore pressure increase and isotropic compression. Absolute permeability, end-point relative permeability to oil & water (kro and krw), initial water saturation and residual oil saturation were measured while the samples deformed. Triaxial compression is a stress path of increasing mean stress while radial extension and pore pressure increase lead to decreasing mean stress. Pore pressure increase experiments were carried out for three initial states: equal axial and confining stresses, axial stress greater than confining stress and confining stress greater than axial stress. Pore pressure was increased under four boundary conditions: 1) constant axial and confining stress; 2) constant axial stress and zero radial strain; 3) zero axial strain and constant confining stress; and 4) zero axial and radial strain. These experiments were designed to mimic geologic conditions where vertical stress was either S1 or S3, the lateral boundary conditions were either zero strain or constant stress, and the vertical boundary conditions were either zero strain or constant stress. Triaxial compression caused a decrease in permeability as the sample compacted, followed by appreciable permeability enhancement during sample dilation. Radial extension led to sample dilation, shear failure and permeability increase from the beginning. The krw and kro increased by 40% and 15% post-compaction respectively for the samples corresponding to lower depths during triaxial compression. For these samples, residual oil saturation decreased by as much as 40%. For radial extension, the permeability enhancement decreased with depth and ranged from 20% to 50% while the residual oil saturation decreased by up to 55%. For both stress paths, more shear-enhanced permeability was observed for samples tested at lower pressures, implying that permeability enhancement is higher for shallower sands. The pore pressure increase experiments showed an increase of only 0-10% in absolute permeability except when the effective stress became close to zero. This could possibly have occurred due to steady state flow not being reached during absolute permeability measurement. The krw curves generally increased as the pore pressure was increased from 0 psi. The increase ranged from 5% to 44% for the different boundary conditions and differential stresses. The kro curves also showed an increasing trend for most of the cases. The residual oil saturation decreased by 40-60% for samples corresponding to shallow depths while it increased by 0-10% for samples corresponding to greater depths. The reservoirs with high differential stress are more conducive to favorable changes in permeability and residual oil saturation. These results suggested that a decreasing mean stress path is more beneficial for production increase than an increasing mean stress path. The unconsolidated sands are over-consolidated because of previous ice loading which makes the sand matrix stiffer. In this work, it was found that over-consolidation, as expected, decreased the porosity and permeability (40-50%) and increased the Young’s and bulk moduli of the sand. The result is sand which failed at higher than expected stress during triaxial compression. Overall, results show that lab experiments support increased permeability due to steam injection operations in heavy oil, and more importantly, the observed reduction in residual oil saturation implies SAGD induced deformation should improve recovery factors. text

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Dissertations / Theses on the topic 'Stem ends'

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