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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The development of tissue explant and embryonic stem cell derived models to investigate the molecular and cellular mechanisms that coordinate vertebrate haematopoiesis and angiogenesis

Evans, Amanda Lisabeth January 2013 (has links)
Understanding the processes that control the formation of blood (haematopoiesis), and blood vessels (vasculogenesis and angiogenesis) in vivo has huge clinical importance. The complex three-dimensional architecture of blood vessels is dynamic and aberrant regulation of either the growth or function of the vascular system may potentiate the spread of tumours, resulting in failure of physiological processes such as implantation and placental development, leading to a range of angiogenesis associated disorders for example diabetic retinopathy. Both embryonic and adult haematopoiesis are also three-dimensional, dynamic processes in which deregulation may result in blood disorders or leukaemia. The experiments herein describe my contribution to investigations into the molecular mechanisms involved in haematopoiesis and angiogenesis over a period of approximately 15 years, taking advantage of technical advances as they became available and adapting them to specific cell models. For example, microarray technology has facilitated discovery of new pathways and transcripts implicated in normal and pathological angiogenesis; central to this mechanism is the role of vascular endothelial growth factor (VEGF), a mitogen specific to endothelial cells. Chromosome immunoprecipitation (ChIP) technology subsequently revealed pathways of early mesoderm formation and the importance of gastrulation in this process. Transcriptional targets of the T-box transcription factor Brachyury were subsequently determined. Throughout this work, the human female reproductive tract provided a unique resource, as one of the rare sites of physiological angiogenesis with which to investigate endothelial cell biology and haematopoiesis. Embryonic stem cell-derived embryoid bodies subsequently proved to be an excellent model for the study of early blood vessel development in three dimensions (2003-5), and to follow early mesoderm development (2006-2010). Targets of Brachyury revealed the close association between blood vessel development, haematopoiesis and early mesoderm formation via a common haemangioblast precursor for blood and endothelial cell lineages. Data gathered by myself, and colleagues, from gene expression and transcription factor analysis is now being used to create lineage codes or routemaps for differentiation of stem cells to mature cells in-vitro and it is now possible to produce mature megakaryocytes and erythrocytes in vitro. The current challenge is to produce fully functional human platelets and enucleated red blood cells. Combined with the use of autologous induced pluripotent stem cells (iPSCs) this makes patientspecific tailoring of cell-based therapies a real possibility.
2

Estudo do Efeito Combinado da Radiólise e Fratura sob Tensão Ambiental no Policarbonato Nacional

SILVA, Pietro Paolo Jorge Corrêa Greco P de Oliveira e 26 March 2015 (has links)
Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2016-01-19T18:26:29Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese.pdf: 4185723 bytes, checksum: a60fe4f68c25e0ae1b815fb488c72847 (MD5) / Made available in DSpace on 2016-01-19T18:26:29Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese.pdf: 4185723 bytes, checksum: a60fe4f68c25e0ae1b815fb488c72847 (MD5) Previous issue date: 2015-03-26 / O policarbonato (PC) é um polímero termoplástico amorfo, transparente e com excelentes propriedades mecânicas, como alta rigidez, ductibilidade e tenacidade. Ele tem sido utilizado em artefatos médicos, plantas de usinas nucleares e instalações de medicina nuclear. Nestas aplicações, frequentemente, fica exposto à radiação gama, seja por esterilização de artefatos médicos ou em serviço. Em muitas ocasiões, também é exposto a líquidos como álcoois, detergentes, óleos, etc., utilizados normalmente para sua limpeza, e pode sofrer o efeito de trincamento/fratura sob tensão ambiental – environmental stress cracking - ESC. No presente trabalho, amostras de policarbonato Durolon® em duas formulações – padrão (STD) e com aditivo radioestabilizante (ADT) – foram submetidas a doses de radiação gama na faixa de 25 a 200 kGy e/ou expostos à ação de metanol, etanol e isopropanol e caracterizadas por diversas técnicas, como análises viscosimétricas e térmicas, ensaios de sorção, ensaios mecânicos, microscopia óptica e eletrônica de varredura e espectroscopia UV-VIS. As análises em viscosimetria capilar mostraram que o PC Durolon® sofre predominantemente cisão da cadeia principal, nas doses de 25, 50, 75, 100 e 200 kGy, tanto na formulação padrão como na aditivada. As análises térmicas demonstraram que as temperaturas de máxima decomposição térmica, Tmáx, assim como de transição vítrea, Tg, não sofreram alterações significativas em função das doses de radiação gama, indicando que além do PC ter excelente estabilidade térmica, a adição do protetor radiolítico não altera essa propriedade em doses até 200 kGy. Nos experimentos de sorção, foram calculados os parâmetros de difusão, D, para os três líquidos e foi observado que o metanol e o etanol atuam como agentes causadores de ESC, sendo o primeiro mais agressivo, enquanto que o isopropanol não atuou como agente causador de ESC no PC. Foi observado também que o efeito combinado de ESC mais radiólise potencializa a ação do líquido no polímero, assim como também foi observado que as amostras com aditivo radioestabilizante em sua formulação foram mais susceptíveis à ação ESC do metanol e etanol. Os ensaios visuais de microscopia óptica, acompanhando o tempo de imersão nos líquidos, confirmaram os dados obtidos para os parâmetros de difusão dos líquidos tensoativos. Os dados em espectroscopia UV-VIS indicaram que o PC na formulação padrão sofre um grau de amarelamento, detectado nas regiões próximas ao comprimento de onda de 420 nm, consideravelmente maior do que a formulação PC-ADT. Ensaios mecânicos de tração em duas velocidades de garra, 2 mm/min e 20 mm/min, foram realizados nas amostras de PC-STD e os dados indicaram que o PC é consideravelmente resistente à radiação, já que até em doses de 200 kGy conservou praticamente estável suas propriedades mecânicas. Entretanto, quando se ensaiaram mecanicamente os corpos de prova expondo-os ao metanol e isopropanol observou-se que ambos diminuíram drasticamente a capacidade do PC de se alongar, diminuindo sua ductibilidade, e tornando-o frágil. Ademais, foi observado que o isopropanol atuou mais severamente nessa fragilização do que o metanol. Uma hipótese foi elaborada para explicar tal comportamento baseada nos parâmetros de solubilidade de Hansen e no tamanho das moléculas dos líquidos. / Polycarbonate (PC) is a thermoplastic and amorphous polymer, has good transparence and has excellent mechanical properties such as high hardness, ductility and toughness. It has been used in medical devices, nuclear power plants and nuclear medicine facilities. Often it is exposed to gamma radiation, either by sterilization of medical devices or in service. On many occasions, they are also exposed to liquids such as alcohols, detergents, oils, etc., normally used for cleaning, and the polymer can suffer the effect of environmental stress cracking - ESC. In the present work, samples of Durolon® polycarbonate in two formulations - standard (STD) and with radio stabilizer additive (ADT) - were subjected to gamma radiation doses in the range from 25 to 200 kGy and / or exposed to the action of methanol, ethanol and isopropanol and characterized by various techniques such as viscosimetric and thermal analysis, sorption testing, mechanical testing, optical microscopy, SEM and UV-VIS spectroscopy. Capillary viscometry showed that the Durolon® PC undergo mainly main chain scission at doses of 25, 50, 75, 100 and 200 kGy, both in standard formulation as with the additive. Thermal analysis showed that the maxim rate temperature of thermal decomposition, Tmáx, as the glass transition, Tg, did not change significantly as a function of gamma radiation doses, indicating that in addition to PC has excellent thermal stability, the addition of radiolytic protector additive does not change this property in doses up to 200 kGy. In sorption experiments, it was calculated the diffusion parameters, D, from the three liquids and it was observed that methanol and ethanol act as ESC agents, and the former more aggressively than the latter, while isopropanol did not act as a ESC agent in PC. It was also observed that the combined effect of ESC with radiolysis increased the action of the liquid in the polymer, as it was also observed that samples with additive in their formulations were more susceptible to ESC action of methanol and ethanol. Visual testing and optical microscopy, following the time of immersion in liquids, confirmed the data obtained for the diffusion parameters of the surface-active liquids. Data for UV-VIS spectroscopy indicated that the PC standard formulation suffers a degree of yellowing, detected in wavelength near from 420 nm, considerably higher than the formulation with radiolytic protector additive. Tensile tests in two speeds, 2 mm / min and 20 mm / min were performed on samples of PC-STD and the data indicated that the PC has a good resistance to radiation, since until doses up to 200 kGy PC keep their excellent mechanical properties. However, when the samples tested were exposed to methanol and isopropanol it was observed that both solvents dramatically decreased the ability of the PC to stretch, decreasing its ductility, and making it brittle. Furthermore, it was observed that the isopropanol worked most severely than methanol on the weakening of polycarbonate. A hypothesis was developed to explain such behavior based on Hansen solubility parameters and in the sizes of liquid molecules too.
3

Epithelial-to-mesenchymal stem cell transition in a human organ: Lessons from Lichen Planopilaris

Imanishi, H., Answell, David M., Chéret, J., Harries, M., Bertolini, M., Sepp, N., Biro, T., Poblet, E., Jimenez, F., Hardman, J., Panicker, S.P., Ward, C.M., Paus, R. 06 May 2020 (has links)
Yes / Epithelial-to-mesenchymal transition (EMT) is critical for embryonic development and wound healing, and occurs in fibrotic disease and carcinoma. Here, we show that EMT also occurs within the bulge, the epithelial stem cell (eSC) niche of human scalp hair follicles, during the inflammatory permanent alopecia, lichen planopilaris. We show that a molecular EMT signature can be experimentally induced in healthy human eSCs in situ by antagonizing E-cadherin, combined with transforming growth factor-β1, epidermal growth factor, and IFN-γ administration, which to our knowledge has not been reported previously. Moreover, induction of EMT within primary human eSCs can be prevented and even partially reversed ex vivo by peroxisome proliferator−activated receptor-γ agonists, likely through suppression of the transforming growth factor-β signaling pathway. Furthermore, we show that peroxisome proliferator−activated receptor-γ agonists also attenuates the EMT signature even in lesional lichen planopilaris hair follicles ex vivo. We introduce lichen planopilaris as a model disease for pathological EMT in human adult eSCs, report a preclinical assay for therapeutically manipulating eSC EMT within a healthy human (mini-)organ, and show that peroxisome proliferator−activated receptor-γ agonists are promising agents for suppressing and partially reversing EMT in human hair follicles eSCs ex vivo, including in lichen planopilaris.
4

Full spectrum : Amnesty International and economic, social, and cultural rights

Rowe, Paul W. 04 June 2009
In 2001, Amnesty International, the worlds largest international human rights non-governmental organization, made the decision to change its narrow mandate into a much broader mission statement that called for the protection and promotion of both civil and political rights and economic, social and cultural rights. Although the organization had added to its original mandate core concerning the release of prisoners of conscience before, the addition of economic, social, and cultural rights represented a major shift away from Amnesty Internationals classic focus on civil and political rights. Amnesty Internationals decision to promote all of the human rights listed in the United Nations Universal Declaration of Human Rights and become a full spectrum human rights defender was a controversial one within the organization. The debate by the Amnesty membership over whether to accept an expanded form of mandate took place within the organization over a period of a decade before any changes were made. Concerns and fears over accepting economic, social and cultural rights into the mandate ranged from the practical to the theoretical.<p> This thesis will look at the decision made by Amnesty International to begin actively promoting and defending economic, social and cultural rights. It will examine why a leading human rights organization decided to modify its focus considerably and what the challenges were in doing this. In exploring the issues of contention brought up during the debates by the organizations membership, the larger questions surrounding international political acceptance of economic, social, and cultural rights will be examined.
5

Full spectrum : Amnesty International and economic, social, and cultural rights

Rowe, Paul W. 04 June 2009 (has links)
In 2001, Amnesty International, the worlds largest international human rights non-governmental organization, made the decision to change its narrow mandate into a much broader mission statement that called for the protection and promotion of both civil and political rights and economic, social and cultural rights. Although the organization had added to its original mandate core concerning the release of prisoners of conscience before, the addition of economic, social, and cultural rights represented a major shift away from Amnesty Internationals classic focus on civil and political rights. Amnesty Internationals decision to promote all of the human rights listed in the United Nations Universal Declaration of Human Rights and become a full spectrum human rights defender was a controversial one within the organization. The debate by the Amnesty membership over whether to accept an expanded form of mandate took place within the organization over a period of a decade before any changes were made. Concerns and fears over accepting economic, social and cultural rights into the mandate ranged from the practical to the theoretical.<p> This thesis will look at the decision made by Amnesty International to begin actively promoting and defending economic, social and cultural rights. It will examine why a leading human rights organization decided to modify its focus considerably and what the challenges were in doing this. In exploring the issues of contention brought up during the debates by the organizations membership, the larger questions surrounding international political acceptance of economic, social, and cultural rights will be examined.
6

Biologiškai aktyvių junginių chromatografinė analizė paprastojo rapontiko (Rhaponticum carthamoides (DC.)Iljin) ekstraktuose / Chromatographic analysis of biologically active compounds in rhaponticum carthamoides (DC.) iljin extracts

Frolova, Ana 10 August 2009 (has links)
Paprastasis rapontikas (Rhaponticum carthamoides (DC.) Iljin) priklauso graižažiedžių šeimai, savaime augantis pietų Sibire [1]. Daugiametis žolinis augalas. Sinonimai: Leuzea carthamoides, Stemmacantha carthamoides, maralinė šaknis [2]. Paprastojo rapontiko ekstraktai pasižymi plačiu spektru teigiamo poveikio: pagerina miegą, apetitą, nuotaiką, fizinę ir psichinę būklę [3], druskų apytaką, virškinimą, stabdomas navikų vystymasis [4], stimuliuoja centrinę nervų, širdies ir kraujagyslių sistemas [1], pasižymi hipolipideminiu [5], psichostimuliuojančiu [4] vabzdžius atbaidančiu, imuninę sistemą stiprinančiu poveikiu, taikomas lėtiniam alkoholizmui, impotencijai gydyti [4]. Darbo tikslas: atlikti biologiškai aktyvių junginių chromatografinę analizę paprastojo rapontiko (Rhaponticum carthamoides (DC.) Iljin) ekstraktuose. Augalinė žaliava. Analizei naudota paprastojo rapontiko augalinė žaliava (lapai) rinkta VDU KBS 2006 metų gegužės – spalio mėnesiais. Džiovinama gerai vėdinamoje patalpoje, vengiant tiesioginių saulės spindulių 15 – 20 °С temperatūroje. Eksperimentinė dalis. Metanoliniai paprastojo rapontiko ekstraktai buvo ruošiami 1g susmulkintos augalinės žaliavos užpilant 10 ml 75 % metanoliu ir paliekant 24 valandoms purtyklėje. Gautas ekstraktas filtruojamas. Optimizuotas kietafazės ekstrakcijos metodas metanoliniams paprastojo rapontiko ekstraktams; nustatyti suminiai fenolinių junginių ir flavonoidų kiekiai bei antioksidacinis aktyvumas fotometriniu metodu; atlikta... [toliau žr. visą tekstą] / Rhaponticum (Rhaponticum carthamoides (DC.) Iljin) is an herbaceous perennial plant from the family Asteraceae that inhabits the sub-alpine zone. It can be found growing wild in Southern Siberia, Kazakhstan, the Altay region. Synonyms founded in literature: Maral root, Leuzea carthamoides, Stemmacantha carthamoides. Research indicates that extracts of Rhaponticum carthamoides may have a beneficial effect on impotence, memory and learning, cardiovascular and CN systems, increasing working capacity of tired skeletal muscles, as well as anabolic and adaptogenic processes, can help break addictive behaviours. The aim of this study is to analyse the biologically active compounds in Rhaponticum carthamoides (dc.) Iljin extracts by means of chromatographic method. Raw material of Rhaponticum carthamoides (DC) Iljin. The plant material (21 samples) was collected from the collection of medicinal plants at Kaunas Botanical Garden of Vytautas Magnus University at different vegetation phases during May–October, 2006. Freshly cut plants were sorted out and dried in the drying room at 15-20°C temperature. Experimental. Into 1g of raw material 10 ml of 75% methanol was added and placed into shaker for 24 h. The methanolic extracts were filtered. For measuring of total amount of phenolics, flavonoids compounds and antioxidant activity in methanolic extracts spectrophotometer was used. For qualitative and quantitative investigation of flavonoids high performance liquid chromatography was... [to full text]
7

Antihistamininių vaistų (klemastino fumarato, loratadino, desloratadino) mišinio išskyrimas iš kraujo plazmos ir identifikavimas efektyviosios skysčių chromatografijos metodu / Antihistamines (clemastine fumarate, loratadine, desloratadine) extraction from human plasma and identification using high performance liquid chromatography

Zdanytė, Birutė 30 June 2014 (has links)
Darbo tikslas: optimizuoti metodiką, kuria būtų galima atlikti antihistamininių vaistų mišinio, sudaryto iš klemastino fumarato, loratadino ir desloratadino, ekstrakciją iš kraujo plazmos ir kokybinį nustatymą efektyviosios skysčių chromatografijos metodu. Darbo uždaviniai: Atlikti mokslinės literatūros analizę siekiant įvertinti antihistamininių vaistų savybes ir pasirinktų junginių ekstrakcijos iš kraujo plazmos ir tapatybės nusatymo metodikas. Optimizuoti ir validuoti ESC metodiką kokybiniam pasirinktų preparatų mišinio nustatymui iš kraujo plazmos. Parinkti klemastino fumarato, loratadino ir desloratadino skysčių – skysčių ekstrakcijos iš kraujo plazmos sąlygas. Apibendrinti gautus ekstrakcijos ir ESC rezultatus. Metodai: skysčių – skysčių ekstrakcija ir ESC. Tyrimo objektas: kraujo plazma, į kurią įterpti antihistamininiai vaistai klemastino fumaratas, loratadinas, desloratadinas ir jų mišinys. Rezultatai: tiriamųjų medžiagų sulaikymo laikai: desloratatadino apie – 5,9 min, loratadino – apie 11,4 min, klemastino fumarato – apie 13,2 min. Validuota ESC atlikimo metodika. Atliekant ekstrakciją su trichlormetanu neišsiekstrahavo nei vienas tiriamasis junginys, su dichlormetanu – loratadinas, su dietileteriu ir cikloheksanu – visi trys tiriamieji junginiai. Išvados: 1. Atlikta mokslinės literatūros analizė, apžvelgiant antihistamininių vaistų savybes, ekstrakcijos iš kraujo plazmos būdus bei identifikavimo metodus, didžiausią dėmesį skiriant efektyviajai skysčių... [toliau žr. visą tekstą] / Aim: to optimise a method, by which mixture of antihistamines containing clemastine fumarate, loratadine and desloratadine could be extracted from human plasma and qualitative determination using high performance liquid chromatogrophy could be made. Tasks: to carry out analysis of scientific literature and evaluate characteristics of antihistamines and methods of chosen compounds extraction from human plasma and identity determination. Optimise and validate HPLC method for qualitative determination of chosen medicines. Select conditions suitable for chosen antihistamines liquid – liquid extraction from human plasma. Carry out qualitative determination of clemastine fumarate, loratadine and desloratadine in human plasma using validated HPLC method. Summarize results of extraction and HPLC. Methods: liquid – liquid extraction and HPLC. Object: human plasma with embedded antihistamines: clemastine fumarate, loratadine, deloratadine and their mixture. Results: retention times of test substances: desloratadine – 5,9 min, loratadine – 11,4 min, clemastine fumarate – 13,2 min. HPLC method was validated. None of the compounds were extracted using trichlormethan. Only loratadine was extracted using dichlormethan. All three compounds were extracted using diethyl ether and cyclohexane. Conclusions: 1. Analysis of scientific literature was caried out, characteristics of antihistamines, methods of extraction from human plasma and identity determination of chosen compounds were overviewed... [to full text]
8

Evaluation of an Aquavac-Esc® booster on production of food-size channel catfish Ictalurus punctatus in earthen ponds

McNeely, Joshua P., Terhune, Jeffery S. January 2006 (has links) (PDF)
Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.
9

Evaluation of the live attenuated vaccine Aquavac Esc and the effects of a primary nursery phases on the production of channel catfish fingerling in earthen ponds

Carrias, Abel Antonio, Terhune, Jeffrey S. January 2005 (has links) (PDF)
Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.
10

The role of Chlamydia trachomatis infection in adverse pregnancy outcomes

Giakoumelou, Sevasti January 2017 (has links)
Chlamydia trachomatis (Ct), the most common sexually transmitted bacterium, has been associated with adverse pregnancy outcomes including controversial data on miscarriage, intrauterine growth restriction and low birth weight, however the causative mechanisms are unknown. A successful pregnancy requires normal endometrial stromal cell (ESC) decidualisation and trophoblast invasion, processes that involve chemokine action and lead to successful implantation. My objectives were to determine whether Ct infection impacts upon ESC decidualisation and chemokine secretion on human primary ESC invitro, to investigate the role of Ct infection in pregnancy in-vivo using a murine model of pregnancy and to investigate the role of Ct in miscarriage in a statistically powered case control study. A novel finding is that Ct can infect and proliferate in ESC, resulting in suboptimal decidualisation as measured by decidualisation marker prolactin’s reduced mRNA and protein levels in infected ESC. Furthermore, the altered secreted chemokine profile of decidualised ESC suggests an attenuated innate immune response from infected ESC. Focusing on chemokines C-X-C motif chemokine 12 (CXCL12) and CXCL16, important for trophoblast invasion, decreased mRNA and protein concentrations were detected in infected decidualised cells. From the in-vivo mouse model of past Ct infection in pregnancy, it was demonstrated that Ct infection did neither affect the fertility of the mice, pregnancy or resorption numbers in C3H mice nor alter embryonic and placental weight on e12 embryos. However, Ct infection caused reduction of embryo and placenta weight on e14 embryos. Finally, preliminary data from the case control study indicate that past Ct infection is not associated with miscarriage. Our in house PGP3 ELISA that detects past Ct infection was more sensitive than a commercially available MOMP ELISA. My data suggests that Ct infection affects pregnancy during the implantation stage by impairing decidualisation and altering chemokine secretion predisposing for adverse pregnancy outcomes that include growth restriction during later gestation.

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