Clostridium perfringens is a leading cause of food poisoning annually in the United States. Ingested C. perfringens vegetative cells respond to the acidic conditions of the stomach by initiating sporulation. The process of sporulation is essential in the formation of an enterotoxin (CPE) that is responsible for the symptoms of acute food poisoning. During sporulation, the cell must differentiate into the mother cell and the forespore. Studies in Bacillus subtilis have shown that gene expression during sporulation is compartmentalized, with different genes expressed in the mother cell and the forespore. The cell-specific RNA polymerase sigma factors coordinate the development of the differentiating cell. These sigma factors are Ï F, Ï E, Ï G, and Ï K. The C. perfringens cpe gene, encoding the enterotoxin CPE, is transcribed from three promoters, P1, P2, and P3. P2 and P3 were previously proposed to be Ï E-dependent, and P1 was proposed to be Ï K-dependent based on consensus recognition sequences. In this study, mutations were introduced into the sigE and sigK genes of C. perfringens. In the sigE and sigK mutants, promoter fusion assays indicated that there was no transcription of cpe in either mutant. We also determined through transcriptional analyses that Ï E-associated RNA polymerase and Ï K-associated RNA polymerase co-regulate the transcription of each other. RT-PCR analyses indicated that Ï K is a very early acting sigma factor. The evidence provided here shows that the regulation of sporulation in C. perfringens is not the same as it is in B. subtilis, as previously proposed. / Master of Science

Foi feito um estudo a partir dos dados provenientes das fichas de notificação do atendimento Centro de Controle de Intoxicações da Prefeitura do Município de São Paulo, CCI-SP no período de 1998 a 2002 com o objetivo de avaliar as intoxicações na população. Crianças de 1 a 4 anos foi o grupo mais exposto, com 38,8% seguido pelos adultos de 20 a 29 anos, com 14,4% do total dos atendimentos. A circunstância acidental foi a principal razão das exposições, especialmente para crianças de 1 a 4 anos, com 66,4% das ocorrências. A tentativa de suicídio foi a circunstância mais freqüente nas faixas etárias de 15 a 19 anos (20,9%) e de 20 a 29 anos (32,4%). Os medicamentos (43,4%), liderados pelos psicofármacos, foram os agentes mais freqüentes nas exposições, seguidos pelos produtos químicos de uso domiciliar (16,5%), especialmente produtos a base de hipoclorito de sódio. Ações de prevenção e educação da população frente ao risco das intoxicações foram sugeridas. / Data collected from Poison Control Center of Prefeitura do Município de São Paulo registration sheets reporting from 1998 to 2002 were used in order to evaluate the poisoning among the population. The study shows that children aged 1-4, corresponding to 38,8%, followed by the adults (20-29 years old) corresponding to 14,4%, were the main affected groups from the total cases of poisoning exposures. The accidental circumstance was the major cause of the exposures, especially in the 1-4 age group with corresponding to 66,4% of poisoning cases. The suicide attempts are higher among adolescents between ages from 15 to 19 (20,9%) and adults from 20 to 29 (32,4%). The medicine drugs represent 43,4% of all poisoning cases, with psychotropics ranking followed by household products (16,5%), in special solutions of sodium hypochlorite. The study suggests preventive actions and public education to reduce risks of poisoning.

This work focuses on understanding the heterogeneous/homogeneous nature of the catalytic species for a variety of immobilized metal precatalysts used for C-C coupling reactions. These precatalysts include: (i) tethered organometallic palladium pincer complexes, (ii) an encapsulated small molecule palladium complex in a polymer matrix, (iii) mercapto-modified mesoporous silica metalated with palladium acetate, and (iv) amino-functionalized mesoporous silicas metalated with Ni(II). As part of this investigation, the use of metal scavengers as selective poisons of homogeneous catalysis is introduced and investigated as a test for distinguishing heterogeneous from homogeneous catalysis. The premise of this test is that insoluble materials functionalized with metal binding sites can be used to selectively remove soluble metal, but will not interfere with catalysis from immobilized metal. In this way the test can definitely distinguish between surface and solution catalysis of immobilized metal precatalysts. This work investigates three different C-C coupling reactions catalyzed by the immobilized metal precatalysts mentioned above. These reactions include the Heck, Suzuki, and Kumada reactions. In all cases it is found that catalysis is solely from leached metal. Three different metal scavenging materials are presented as selective poisons that can be used to determine solution vs. surface catalysis. These selective poisons include poly(vinylpyridine), QuadrapureTM TU, and thiol-functionalized mesoporous silica. The results are contrasted against the current understanding of this field of research and subtleties of tests for distinguishing homogeneous from heterogeneous catalysis are presented and discussed.

Thesis (M. Heal. Sc.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 85-88). Also available via the World Wide Web.

Foi feito um estudo a partir dos dados provenientes das fichas de notificação do atendimento Centro de Controle de Intoxicações da Prefeitura do Município de São Paulo, CCI-SP no período de 1998 a 2002 com o objetivo de avaliar as intoxicações na população. Crianças de 1 a 4 anos foi o grupo mais exposto, com 38,8% seguido pelos adultos de 20 a 29 anos, com 14,4% do total dos atendimentos. A circunstância acidental foi a principal razão das exposições, especialmente para crianças de 1 a 4 anos, com 66,4% das ocorrências. A tentativa de suicídio foi a circunstância mais freqüente nas faixas etárias de 15 a 19 anos (20,9%) e de 20 a 29 anos (32,4%). Os medicamentos (43,4%), liderados pelos psicofármacos, foram os agentes mais freqüentes nas exposições, seguidos pelos produtos químicos de uso domiciliar (16,5%), especialmente produtos a base de hipoclorito de sódio. Ações de prevenção e educação da população frente ao risco das intoxicações foram sugeridas. / Data collected from Poison Control Center of Prefeitura do Município de São Paulo registration sheets reporting from 1998 to 2002 were used in order to evaluate the poisoning among the population. The study shows that children aged 1-4, corresponding to 38,8%, followed by the adults (20-29 years old) corresponding to 14,4%, were the main affected groups from the total cases of poisoning exposures. The accidental circumstance was the major cause of the exposures, especially in the 1-4 age group with corresponding to 66,4% of poisoning cases. The suicide attempts are higher among adolescents between ages from 15 to 19 (20,9%) and adults from 20 to 29 (32,4%). The medicine drugs represent 43,4% of all poisoning cases, with psychotropics ranking followed by household products (16,5%), in special solutions of sodium hypochlorite. The study suggests preventive actions and public education to reduce risks of poisoning.

Schätzungen über die Gesamtzahl der Vergiftungen in Deutschland belaufen sich auf 150 - 200.000 pro Jahr. In Deutschland machen Vergiftungsfälle 10% der in Notaufnahmen und auf Intensivstationen behandelten Patienten aus. Bis dato gibt es in Deutschland nur wenige strukturiert erfasste epidemiologische Daten von vergiftungsbedingten Todesfällen. In der vorliegenden Arbeit wurden die vergiftungsbedingten Todesfälle aus dem Giftinformationszentrum-Nord (GIZ-Nord) für den Zeitraum vom 01.01.1996 bis einschließlich 31.12.2009 retrospektiv analysiert. Insbesondere vor dem Hintergrund der Toxikovigilanz konnten folgende Fragen zu Risikokonstellationen für letale Vergiftungen durch diese Arbeit beantwortet werden: 1. Gibt es bei den vergiftungsbedingten Todesfällen jahreszeitliche Schwankungen? Ja, die vergiftungsbedingten bzw. suizidalen letalen Intoxikationen zeigen jahreszeitliche Schwankungen mit einem maximalen Anteil im Frühling von knapp 30% und dem geringsten Anteil im Herbst mit etwa 20%. 2. Bergen die iatrogen bedingten Vergiftungen ein besonderes Mortalitätsrisiko? Ja, die iatrogenen Vergiftungen weisen die höchste Mortalitätsrate mit knapp 5 ‰ aller iatrogenen Expositionen auf, vor allem bei parenteraler Arzneimittelapplikation. 3. Stellen Adoleszente (Heranwachsende und Jugendliche) und Senioren über 70 Jahre besonders gefährdete Altersgruppen für letale Intoxikationen dar? Ja, beide Populationen stellen besondere Risikogruppen für vergiftungsbedingte Todesfälle dar. Vor allem männliche Heranwachsende repräsentieren eine Risikogruppe für letale Intoxikationen durch Abusus. 30% aller vergiftungbedingten Todesfälle durch Abusus sind bei männlichen Jugendlichen aufgetreten. Senioren (Männer und Frauen) über 70 Jahre sind eine im hohen Maß gefährdete Altersgruppe für letale Vergiftungen. Einerseits ist die relative Mortalitätsrate bezogen auf alle Expositionen dieser Altersgruppe mit knapp 6 ‰ am höchsten. Andererseits zeigen die suizidalen Intoxikationen bei den Senioren eine zunehmende Tendenz. Außerdem bilden Senioren mit einem Anteil von 24% die Gruppe mit dem größten Anteil an den letalen nicht suizidalen Intoxikationen. Mehr als 70% der akzidentellen letalen Intoxikationen und 50% der letalen Vergiftungen durch Verwechslungen betreffen Senioren, dabei sind Frauen mehr als 3fach häufiger betroffen als Männer. Darüber hinaus sind Senioren durch Aspiration schäumender, prinzipiell niedrig toxischer Kosmetika und tensidhaltiger Chemikalien besonders gefährdet. 4. Gibt es bei den gewerblichen Expositionen besondere Risikokonstellationen? Ja, die gewerblichen Expositionen, die mit einer hohen Männerlastigkeit auftreten, bergen eine hohe letale Intoxikationsgefahr. Vor allem bei den gewerblichen inhalativen Expositionen von toxischen Reizgasen besteht eine Gefährdung für die betroffenen Beschäftigten, aber auch für die nicht selbstgeschützten Ersthelfer: 6% der inhalativen gewerblichen Intoxikationen durch Schwefelwasserstoff endeten letal.

Chan Tai-Wai David. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 263-275). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

by Lau Wai Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1981. / Bibliography: leaves 189-205.

Made available in DSpace on 2016-04-28T20:18:29Z (GMT). No. of bitstreams: 1 2008 - Michel Jose Sales Abdalla Helayel.pdf: 2764990 bytes, checksum: 2ef0f5307007bc87483b82ee19e1b257 (MD5) Previous issue date: 2008-09-17 / Natural poisoning by Pseudocalymma elegans is described in a cow in the county of Rio Bonito, RJ. Also decribed is the experimental reproduction of this poisoning in three calves (1.0, 0.5 and 0.25 g/kg of the fresh plant) and in five rabbits (0.5 0.25 0.125 0.0625 and 0.0312 g/kg of the dried and ground plant) with the plant collected in the area where the deaths had occurred. Post-mortem and histopathological examinations of the natural case in the cow did not reveal significant alterations. Oral administration of 1g/kg of the sprouts of P. elegans caused death of the calf 5hours and 30 minutes after beginning of the administration of the plant. The dose of 0.5 g/kg caused death of the animal after 76 hours and 36 minutes. The 0.25g/kg dose caused only clinical signs which consisted of heart palpitation and arrhythmia, increase of breathing frequency, reluctance in moving, positive vein pulse, ingurgitated jugular veins, mooing, falling down, peddling movements followed by death. At post-mortem examination the lesions were those of acute heart insufficiency, and histopatologic examination revealed the typical kidney lesion (hydropic degeneration in the distal convoluted tubules) seen in the poisoning by plants that cause "sudden death". In the experimentally poisoned rabbits the clinical course was from less than one to two minutes. The histopatological examination of the kidney of two rabbits also revealed that characteristic microscopic kidney lesion. This is the first description of a natural case of P. elegans poisoning in cattle with post-mortem and histopatological description. The occurrence of the plant in the county of Rio Bonito had not been known by the veterinarians. It is conluded that the plant has a higher toxicity as described before. / Descreve-se a intoxica??o natural por Pseudocalymma elegans em pelo menos um bovino em Rio Bonito, RJ e a reprodu??o experimental dessa intoxica??o em tr?s bovinos (1, 0,5 e 0,25 g/kg da planta fresca) e em 5 coelhos (0,5 - 0,25 - 0,125- 0,0625 e 0,0312 g/kg da planta dessecada e mo?da) com exemplares dessa planta colhida no local onde ocorreu o ?bito. A necropsia e a histopatologia do bovino intoxicado naturalmente, n?o revelaram altera??es significativas. A administra??o, por via oral, de 1g/kg da brota??o da planta causou o ?bito do bovino dentro de 5h e 30 minutos ap?s o in?cio da administra??o da planta, j? pela administra??o de 0,5 g/kg, o ?bito do animal ocorreu ap?s 76 horas e 36 minutos. A dose de 0,25g/kg foi capaz de causar sintomas, mas n?o levou ao ?bito. Os sintomas apresentados foram arritmia card?aca, taquicardia, aumento da freq??ncia respirat?ria, relut?ncia em se mover, pulso venoso positivo, jugulares e grandes vasos ingurgitados, mugidos, queda ao solo, movimentos de pedalagem seguido de ?bito. ? necropsia foram verificadas altera??es compat?veis com ?s observadas na insufici?ncia card?aca aguda, e o exame histopatol?gico revelou a les?o renal t?pica (degenera??o hidr?pica em t?bulos contornados distais) de intoxica??o por plantas que causam morte s?bita . Nos coelhos intoxicados experimentalmente a evolu??o variou entre menos de um minuto a dois minutos. O exame histopatol?gico do rim de dois coelhos tamb?m revelou a les?o microsc?pica caracter?stica. Trata-se do primeiro registro, com necropsia e histopatologia, de intoxica??o natural por P. elegans em bovinos. Essa planta ainda n?o havia sido mapeada nessa ?rea do Estado do Rio de Janeiro. Conclui-se que a planta pode ser mais t?xica do que anteriormente descrito.

La photocatalyse est une technique émergente de traitement des déchets qui nécessite un faible apport d’énergie présentée sous forme lumineuse. L’emploi de catalyseurs supportés autorise une séparation efficace des produits de réaction, en dépit d’une réduction de leur surface spécifique. De par les avantages qu’offre la pulvérisation réactive (bonne tenue mécanique, synthèse sur substrats froids, contrôle aisé de la microstructure, …), la synthèse de revêtements de TiO2 par cette technique fait l’objet de recherches intensives.Après une description des mécanismes mis en jeu lors d’une réaction photocatalytique, les phénomènes physiques à la base de la synthèse de revêtements céramiques par pulvérisation réactive à haute pression sont détaillés. Afin de s’affranchir de la contamination du catalyseur par le sodium du verre, une barrière de diffusion de SiNx est intercalée. Les influences de la position du substrat par rapport au flux de vapeur métallique, de la température de recuit, de la pression totale et de l’épaisseur des films catalyseurs sur leurs propriétés physicochimiques et photocatalytiques sont étudiées, autorisant la formulation d’hypothèses quant aux liens qui les unissent. Enfin, des premiers travaux portant sur la synthèse d’un photocatalyseur TiO2-xNy cristallisé in situ à haute pression sont présentés. / AThe photocatalysis is a new way of organic pollutants treatments which needs a low energy supplied under light wave. The use of supported catalyst allows an efficient separation of the reaction products, in spite of their specific area reduction. Owing to the advantages that offers reactive sputtering (good mechanical adhesion, synthesis on cold substrates, easy control of the microstructure, …), the synthesis by this technique of the most promising semiconductor photocatalyst, namely the titanium dioxide, is the subject of intensive researchs. After a description of the mechanisms occurring during a photocatalytic reaction, the physical phenomena at the origin of the ceramic coating synthesis are detailed. In order to hinder the sodium contamination of the catalyst from the glass substrate, a SiNx diffusion barrier is intercalated. The influences of the substrate position relatively to the metallic flux, the annealing temperature, the total pressure and the TiO2 coating thickness on the physico-chemical and photocatalytic properties are investigated allowing the formulation of hypothetic relations combining them. Finally, first studies on in situ crystallized TiO2-xNy photocatalyst deposited at high pressure are presented.