No description available.

No description available.

Androgens are the main regulators of human hair growth stimulating larger, terminal hair development e.g. beard and causing scalp balding, androgenetic alopecia. Hair disorders cause psychological distress but are poorly controlled. Androgens probably act by altering regulatory paracrine factors produced by the mesenchyme-derived dermal papilla. This study aimed to investigate paracrine factors involved in androgen-regulated alopecia, particularly hepatocyte growth factor (HGF) family members, by investigating their in vivo status. Balding and non-balding scalp hair follicles and their component tissues were isolated and analysed by molecular biological methods (reverse transcriptase-polymerase chain reaction (RT-PCR), quantitative PCR and DNA microarray analysis), cell culture and immunohistochemistry. Scalp follicles expressed a range of paracrine messenger genes. The dermal papilla, cultured dermal papilla cells and dermal sheath expressed several HGF family genes, while matrix cells only produced the receptor RON suggesting autocrine roles for HGF and MSP, but a paracrine route only for MSP. Comparing balding and non-balding follicles from the same individuals revealed the expected reduction in several keratin and keratin-related protein genes supporting this approach's validity. There were also significant differences in paracrine factors previously implicated in androgen action by in vitro studies. Several factors believed to increase during androgen stimulation of larger, darker follicles, e.g. IGF-I and SCF, were lowered in balding follicles, while putative inhibitory factors, e.g. TGFß-1, were increased. HGF and MSP and their receptors, c-Met and RON, were significantly reduced. These results increase our understanding of androgen action in human hair follicles; this could lead to better treatments for hair disorders. / Saudi government

No description available.

No description available.

Ron DeSantis has become one of the most important and debated American politicians in recent years largely because of his education policies. This thesis aims to study the existence of conservatism in his laws Stop WOKE Act, Parental Rights in Education Act, and HB 1069 with research questions formulated to study the laws’ conservative idea structures and their similarities and differences. Heywood’s (2021) definition of conservatism lays the ground for the thesis, but it is primarily guided by Marietta’s (2012) four types of American conservatism used to distinguish different conservative types. The method used is a qualitative idea analysis directed by ideal types and a set scale used for a qualitative assessment, which is applied to a material consisting of official legal texts.  The analysis shows that all three laws studied have a Social Conservative and Culture Conservative idea structure. National Defense Conservatism and Economic Conservatism are also expressed, but only in the Stop WOKE Act, while the Parental Rights in Education Act and HB 1069 have similar conservative idea structures. Culture Conservative ideas mainly characterize DeSantis' education policy overall and are the main basis for the debate and criticism surrounding it.

Thesis (M.A.)--Miami University, Dept. of Theatre, 2004. / Title from first page of PDF document. Includes bibliographical references (p. 55-56).

O nucléolo é uma organela subnuclear formada pela atividade transcricional dos genes ribossomais 18S-5.8S-26S (rDNA 45S) e consequente biogênese dos ribossomos. A atividade destes genes resulta na região organizadora do nucléolo (NOR), na forma de uma constrição secundária em cromossomos metafásicos. As constrições secundárias se condensam progressivamente durante a mitose e se descondensam ao final da telófase quando a reestruturação do nucléolo se inicia. Genomas que apresentam mais de um locus de rDNA 45S deve apresentar, obrigatoriamente, pelo menos um par de NORs, enquanto os demais loci poderão ou não serem expressos. O controle da expressão dos genes ribossomais e a formação da cromatina nucleolar são modulados por eventos epigenéticos. Embora alguns pontos sobre o funcionamento dos genes ribossomais e a formação do nucléolo estejam bem estabelecidos, questões como o padrão de condensação da cromatina nucleolar durante a mitose, o padrão de funcionamento de sítios adicionais de genes ribossomais, o papel das modificações epigenéticas na dinâmica da cromatina nucleolar e na expressão do rDNA 45S e o mecanismo de herança dos genes ativos, permanecem abertas. A espécie Crotalaria juncea (Leguminosae-Papilionoideae), com 2n=2x=16 cromossomos, que possui um locus de rDNA 45S no braço curto do cromossomo 1, que sempre forma constrição secundária, e um sítio adicional com atividade facultativa no braço curto do cromossomo 4, é um excelente modelo para o estudo destas questões. No contexto apresentado, foram estudadas a dinâmica de condensação das NORs durante o ciclo celular e sua correlação com a atividade dos genes ribossomais, incluindo o locus adicional, e ainda o papel da metilação da citosina do DNA durante estes processos. Os resultados demonstram que a cromatina da região organizadora do nucléolo segrega em um estado descondensado durante a mitose, na forma de constrição secundária, ou seja, tal estrutura não se condensa durante a metáfase e não volta a se distender no início da telófase. Aparentemente, o que causa correlações equivocadas entre a atividade nucleolar e a observação morfológica da constrição secundária na metáfase é a contração forçada da cromatina da NOR causada por agentes antimitogênicos. Este modelo de segregação em um estado aberto pode ser explicado pela descrição de diversas proteínas que permanecem diretamente ligadas ou indiretamente associadas à região da NOR durante a mitose, funcionando como uma barreira física para a compactação. Ambos os sítios, principais e adicionais, do rDNA 45S presentes em Crotalaria juncea apresentam atividade transcricional, embora o locus do cromossomo 4 mostre atividade facultativa. Ao contrário do que foi anteriormente proposto, uma vez ativo, o locus adicional permanece descondensado durante todo o ciclo mitótico, seguindo o mesmo comportamento dos sítios principais. As constrições secundárias e a cromatina nucleolar são hipermetiladas em nível citológico, independentemente de sua atividade. A aparente hipometilação observada no rDNA 45S em cromossomos mitóticos e núcleos interfásicos se deve ao menor grau de compactação da região organizadora do nucléolo e, consequentemente, à baixa densidade de cromatina. / The nucleolus is a subnuclear organelle formed as a result of transcriptional activity of ribosomal RNA genes 18S-5.8S-26S (45S rDNA) and subsequent ribosome biogenesis. This activity forms the nucleolar organizing region (NOR) as a secondary constriction in metaphase chromosomes. The secondary constrictions progressively condense during mitosis and decondense at the end of telophase, when nucleoli start to reassemble. Genomes presenting more than one 45S rDNA locus must have at least one pair of NOR bearing chromosomes, while other loci may be expressed or not. Ribosomal gene expression and nucleolar chromatin assembly are modulated by specific epigenetic events. Although some topics related to rDNA gene activity and nucleolus formation are well understood, questions such as the behavior of nucleolar chromatin condensation during mitosis, standard functions associated with rDNA additional sites, role of epigenetic modifications in nucleolar chromatin and 45S rDNA expression processes, and inheritance mechanism of active genes, remain to be solved. Crotalaria juncea (Leguminosae - Papilionoideae) has 2n=2x=16 chromosomes and carries a 45S rDNA locus at the short arm of chromosome 1, always presenting a secondary constriction, and an additional site with facultative activity at the short arm of chromosome 4, being an excellent model to resolve these questions. Thus, this study aimed to study NOR condensation dynamics during the cell cycle and its correlation with ribosomal gene activity, including the additional locus, while analyzing the role of rDNA cytosine methylation during this process. The results show that NOR chromatin segregate in a decondensed way throughout mitosis, as a secondary constriction. In other words, this structure does not condense during metaphase and the NOR is not reassembled at the beginning of telophase. Misinterpretations relating nucleolar activity with morphological observations of secondary constrictions, appear to be induced by the artificial contraction of NOR chromatin caused by antimitotic drugs. This segregation model in an open state may be supported by strong diversity of proteins that are maintained attached to NORs during mitosis, serving as a physic barrier for condensation. Both principal and additional 45S rDNA sites of C. juncea are transcriptionally active, although the additional locus in chromosome 4 presented facultative activity depending upon ribosomal request. Unlike what was previously proposed, once the additional site is activated, it remains in an open configuration throughout the cell cycle, similarly to principal site behavior. Secondary constrictions and nucleolar chromatin are hypermethylated at cytological level, regardless of their activity. The seeming hipomethylated state of 45S rDNA in interphase nucleus and mitotic chromosomes is due to a lower compaction level of nucleolar organizing regions and subsequent low chromatin density.

Ce travail de thèse traite de la conception, de l'optimisation et de la modélisation électrique d'une nouvelle génération de composants MOS de puissance, appelés FLIMOS (FLoating Islands MOSFET). La structure FLIMOS permet une nette amélioration de la résistance à l'état passant des transistors MOS de puissance. Comparée à la structure à Superjonction, la structure FLIMOS est très intéressante pour les faibles et moyennes tensions de claquage. Dans un premier temps, nous avons proposé une approche analytique permettant d'estimer la tension de claquage, la résistance passante spécifique et les capacités inter-électrodes de la structure FLIMOS. Par conséquent, nous avons défini la plage des dopages "utiles" de la zone de drift pour laquelle la structure FLIMOS était optimisée. Ensuite, nous avons démontré que le concept des îlots flottants ne dégradait pas les performances dynamiques des composants MOS de puissance. Dans un deuxième temps, un nouveau modèle SPICE des transistors MOS de puissance basse tension à canal court, a été proposé pour la première fois. Ce modèle décrit d'une façon plus exacte la zone de transition entre la zone linéaire et la zone de saturation du transistor MOS de puissance et tient compte, en plus, des effets du canal court sur la tension de seuil et la mobilité. Les paramètres de ce nouveau modèle sont les mêmes que ceux du modèle SPICE niveau 3. Enfin, le modèle a été validé en comparant les résultats des simulations SPICE aux valeurs mesurées.

Le compromis entre la résistance passante spécifique et la tenue en tension a toujours été un point pénalisant les performances statiques des structures MOS de puissance conventionnelles. Depuis 1997, de nouveaux concepts, tels que la Superjonction, la U-diode et la FLI-diode, sont apparus pour dépasser les limites conventionnelles du silicium, qui apparaissaient depuis une vingtaine d'années comme "infranchissables". Deux de ces concepts sont issus de nos travaux de recherche : il s'agit de la U-diode et de la FLI-diode qui font l'objet de ce mémoire. Ces deux diodes ont été étudiées et leur principe de fonctionnement a été appliqué aux composants MOS de puissance latéraux et verticaux. Concernant les composants facilement intégrables, c'est-à-dire essentiellement les composants MOS latéraux, le concept le plus intéressant est celui de la U-diode : dans la gamme des basses tensions de claquage (en dessous de 100 Volts), plusieurs structures, nommées LUDMOS, présentent un excellent compromis entre résistance passante spécifique et tenue en tension proche et même parfois meilleur que la limite du silicium. Concernant les composants MOS verticaux, préférentiellement utilisés en tant que composants discrets, c'est le concept de la FLI-diode qui est apparu le plus "prometteur". En effet, les composants FLIMOS verticaux présentent des tenues en tension supérieures à celle de la jonction plane et des résistances passantes spécifiques fortement améliorées et inférieures à la limite du silicium. La réalisation technologique du premier transistor FLIMOS 80 Volts pour l'électronique automobile du futur (batteries 42 Volts) a permis la validation de ce concept. Grâce à ces nouveaux concepts, de nouvelles limites pour le silicium ont été définies : la limite conventionnelle est désormais dépassée. Les solutions innovantes proposées ont donc montré que le silicium avait encore de l'avenir dans le domaine des composants et de l'intégration de puissance.