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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Influência da queima da cana-de-açúcar nos níveis de HPAs, nitro-HPAs e oxi-HPAs associados ao aerossol atmosférico / Influence of sugar cane burning in the levels PAH, nitro-PAH and oxy-PAH associated to atmospheric particulate matter

Souza, Kely Ferreira de 01 December 2014 (has links)
Os hidrocarbonetos policíclicos aromáticos (HPAs) e seus derivados nitrados (nitro-HPAs) e oxigenados (oxi-HPAs) são compostos de grande interesse devido seus efeitos deletérios à saúde. Estes compostos são encontrados associados ao material particulado atmosférico e são formados durante a combustão de compostos orgânicos, no caso dos HPAs, e também por reações in situ através dos HPAs precursores, no caso dos nitro- e oxi-HPAs. Para avaliar a influência da queima de cana-de-açucar, amostras de material particulado foram coletadas nas cidades de Ourinhos e Araraquara (Estado de São Paulo), regiões afetadas pela queima de cana-de-açucar. Os filtros carregados foram submetidos à extração por Soxhlet, o extrato orgânico foi fracionado por HPLC e as frações de interesse foram analisadas por cromatografia a gás. Foram investigados 12 HPAs, 7 nitro-HPAs e 3 oxi-HPAs. Na cidade de Ourinhos coletou-se material particulado total (MPT) e material particulado em diferentes tamanhos. Os HPAs e a benzantrona (oxi-HPA) apresentaram concentrações maiores nas partículas menores, ao passo que nitro-HPA e os outros dois oxi-HPAs estudados (9-fluorenona e 9,10-antrona) predominaram nas partículas maiores. Em Araraquara foram coletadas amostras de MPT nos períodos diurno e noturno, e amostras de 24h nos períodos de safra e entressafra. Os HPAs e a benzantrona apresentaram predominância no período noturno, sugerindo que esses compostos devem ter sido provenientes de emissões da queima da cana-de-açucar, ao passo que os outros dois oxi-HPAs estudados (9-fluorenona e 9,10-antraquinona) não apresentaram esse comportamento. Os nitro-HPAs foram detectados em poucas amostras noturnas, provavelmente devido ao processo de remoção destes compostos por fotólise durante o dia. As correlações altas entre HPAs e alguns nitro-HPAs sugerem que tais compostos são provenientes provavelmente das mesmas fontes que os HPAs, embora alguns nitro-HPAs possam também ser formados in situ. Os compostos oxi-HPAs apresentaram correlações com alguns HPAs, mas devem ser também oriundos de outras fontes de emissão além da queima da cana-de-açúcar. De um modo geral, a queima desse tipo de biomassa parece influenciar nos níveis atmosféricos dos compostos estudados. / The polycyclic aromatic hydrocarbons (PAH) and their nitrated (nitro-PAH) and oxygenated (oxy-PAH) derivatives are compound of great interest due to their noxious effects on health. These compounds are found associated to the atmospheric particulate matter and are formed during the organic compound combustion, in case of PAH, and also by in situ reactions through the PAH precursors, in case of nitro- and oxy-PAH. In order to evaluate the sugar cane burning influence, particulate matter samples were collected at Ourinhos and Araraquara cities and submitted to Soxhlet extraction, frationating by HPLC and analized by gas-chromatography. 12 PAH, 11 nitro-PAH and 3 oxy-PAH were investigated. Total particulate matter and particulate matter in different particle sizes were collected at Ourinhos. Particulate matter in different particle sizes presented maximum concentration of PAH and benzanthrone (oxi-PAH) in the smaller particles, while nitro-PAH and the two other oxy-PAH (9-fluorenone and 9,10-anthraquinone) predominated in the larger particles. The sampling of total particulate matter in Araraquara was carried out in daytime and nighttime periods and also 24h sampling in harvest and post-harvest seasons. The PAH and the benzanthrone presented predominance in the nighttime period, suggesting sugar cane burning emissions. Moreover, the other two oxy-PAH (9-fluorenone and 9,10-anthraquinone) did not show that behavior. The nitro-PAH were detected in a few samples, and only at nighttime period in some cases. This is probably due to removal by photolysis during the daytime. The correlations between the compounds suggest a commom source between PAH and some nitro-PAH, although nitro-PAH can also be formed in situ. The oxy-PAH presented some correlations with PAH, but it seems that oxygenated PAH have another emission sources appart from burning. Biomass burning seems to influenciate the PAH and derivative levels in atmosphere.
32

Influência da queima da cana-de-açúcar nos níveis de HPAs, nitro-HPAs e oxi-HPAs associados ao aerossol atmosférico / Influence of sugar cane burning in the levels PAH, nitro-PAH and oxy-PAH associated to atmospheric particulate matter

Kely Ferreira de Souza 01 December 2014 (has links)
Os hidrocarbonetos policíclicos aromáticos (HPAs) e seus derivados nitrados (nitro-HPAs) e oxigenados (oxi-HPAs) são compostos de grande interesse devido seus efeitos deletérios à saúde. Estes compostos são encontrados associados ao material particulado atmosférico e são formados durante a combustão de compostos orgânicos, no caso dos HPAs, e também por reações in situ através dos HPAs precursores, no caso dos nitro- e oxi-HPAs. Para avaliar a influência da queima de cana-de-açucar, amostras de material particulado foram coletadas nas cidades de Ourinhos e Araraquara (Estado de São Paulo), regiões afetadas pela queima de cana-de-açucar. Os filtros carregados foram submetidos à extração por Soxhlet, o extrato orgânico foi fracionado por HPLC e as frações de interesse foram analisadas por cromatografia a gás. Foram investigados 12 HPAs, 7 nitro-HPAs e 3 oxi-HPAs. Na cidade de Ourinhos coletou-se material particulado total (MPT) e material particulado em diferentes tamanhos. Os HPAs e a benzantrona (oxi-HPA) apresentaram concentrações maiores nas partículas menores, ao passo que nitro-HPA e os outros dois oxi-HPAs estudados (9-fluorenona e 9,10-antrona) predominaram nas partículas maiores. Em Araraquara foram coletadas amostras de MPT nos períodos diurno e noturno, e amostras de 24h nos períodos de safra e entressafra. Os HPAs e a benzantrona apresentaram predominância no período noturno, sugerindo que esses compostos devem ter sido provenientes de emissões da queima da cana-de-açucar, ao passo que os outros dois oxi-HPAs estudados (9-fluorenona e 9,10-antraquinona) não apresentaram esse comportamento. Os nitro-HPAs foram detectados em poucas amostras noturnas, provavelmente devido ao processo de remoção destes compostos por fotólise durante o dia. As correlações altas entre HPAs e alguns nitro-HPAs sugerem que tais compostos são provenientes provavelmente das mesmas fontes que os HPAs, embora alguns nitro-HPAs possam também ser formados in situ. Os compostos oxi-HPAs apresentaram correlações com alguns HPAs, mas devem ser também oriundos de outras fontes de emissão além da queima da cana-de-açúcar. De um modo geral, a queima desse tipo de biomassa parece influenciar nos níveis atmosféricos dos compostos estudados. / The polycyclic aromatic hydrocarbons (PAH) and their nitrated (nitro-PAH) and oxygenated (oxy-PAH) derivatives are compound of great interest due to their noxious effects on health. These compounds are found associated to the atmospheric particulate matter and are formed during the organic compound combustion, in case of PAH, and also by in situ reactions through the PAH precursors, in case of nitro- and oxy-PAH. In order to evaluate the sugar cane burning influence, particulate matter samples were collected at Ourinhos and Araraquara cities and submitted to Soxhlet extraction, frationating by HPLC and analized by gas-chromatography. 12 PAH, 11 nitro-PAH and 3 oxy-PAH were investigated. Total particulate matter and particulate matter in different particle sizes were collected at Ourinhos. Particulate matter in different particle sizes presented maximum concentration of PAH and benzanthrone (oxi-PAH) in the smaller particles, while nitro-PAH and the two other oxy-PAH (9-fluorenone and 9,10-anthraquinone) predominated in the larger particles. The sampling of total particulate matter in Araraquara was carried out in daytime and nighttime periods and also 24h sampling in harvest and post-harvest seasons. The PAH and the benzanthrone presented predominance in the nighttime period, suggesting sugar cane burning emissions. Moreover, the other two oxy-PAH (9-fluorenone and 9,10-anthraquinone) did not show that behavior. The nitro-PAH were detected in a few samples, and only at nighttime period in some cases. This is probably due to removal by photolysis during the daytime. The correlations between the compounds suggest a commom source between PAH and some nitro-PAH, although nitro-PAH can also be formed in situ. The oxy-PAH presented some correlations with PAH, but it seems that oxygenated PAH have another emission sources appart from burning. Biomass burning seems to influenciate the PAH and derivative levels in atmosphere.
33

Neuroendocrine Function of Female Youth with Callous-Unemotional Traits

Gostisha, Andrew 04 August 2011 (has links)
Callous-unemotional (CU) traits have been shown to designate a particular subgroup of antisocial youth that are particularly violent, recidivistic, and more likely to continue offending in adulthood. Disordered neuroendocrine function may be a mechanism for the development of CU traits. We examined whether altered stress responsivity served as a mechanism linking stress exposure and the expression of CU traits. Participants were 15 incarcerated adolescent girls with CU traits. Measures of CU traits, stress exposure, and salivary cortisol were collected. Results revealed girls with CU traits had higher morning levels of cortisol, an intact cortisol awakening response (CAR), and flatter diurnal rhythms. Results indicated the type of stressor being measured and time since stressor onset are crucial to the interpretation of neuroendocrine function. We also found support for a neurobiological model for the development of CU traits drawing on the Adaptive Calibration Model. Implications of the study and directions for further research are discussed.
34

Coupling of the HPA and HPG Axes

Dismukes, Andrew 20 December 2013 (has links)
The Hypothalamic-Pituitary-Adrenal (HPA) and –Gonadal (HPG) axes have been considered mutually inhibitory; however, emerging evidence supports the proposition that this might not necessarily be the case. This idea is termed “coupling,” in which the HPA-HPG axis are mutually activated or deactivated. Coupling is examined across three data sets with different time-courses of stress exposure, and results demonstrate HPA-HPG co-activation occurs. Furthermore, stress exposure influences this relationship. The discussion shows how it is physiologically possible to have positive coupling or co-activation between these axes according to complex regulatory feedback systems and overlapping neural structures. Findings are interpreted developmentally, because adolescence may be a critical time for this co-activation to occur. Finally, the discussion emphasizes an individual difference perspective because each individual differs in the duration and type of stress they experience, and these exerted individualized effects on HPA-HPG coupling.
35

Estudo da determinação do 1-Nitropireno em material particulado atmosférico /

Azevedo, Ricardo Cambiaghi January 2002 (has links)
Orientador: Mary Rosa Rodrigues de Marchi Santiago da Silva / Banca: Maria Olimpia de Oliveira Rezende / Banca: Alberto José Cavalheiro / Resumo: Os hidrocarbonetos policíclicos aromáticos nitrados (NHPAs) constituem a classe de compostos aromáticos que têm pelo menos um grupo nitro (-NO2) ligado à cadeia aromática de um hidrocarboneto policíclico aromático (HPA). Nos anos 70 a descoberta das propriedades mutagênicas destes compostos, presentes em material particulado atmosférico e na exaustão de motores a diesel, aumentaram o interesse científico sobre a ocorrência dos mesmos no ambiente. Estes compostos, como os HPAs, estão associados a fontes de combustão como automóveis, sistemas de aquecimento (baseados na queima de biomassa ou de combustíveis fósseis); queima de biomassa (cigarro, florestas, culturas agrícolas, etc), por causa disso pode-se prever que tenham uma distribuição abrangente no ambiente. Os NHPAs são produtos da reação dos HPAs com óxidos de nitrogênio na atmosfera, apresentando-se em concentrações muito baixas neste compartimento ambiental. A análise de NHPAs é muito difícil, principalmente pelos artefactos de amostragem e pela interferência analítica causada por HPAs e outros compostos. Assim sendo, a investigação de métodos alternativos que sejam sensíveis e seletivos são de extrema importância na determinação de NHPAs em amostras atmosféricas. Neste trabalho estudou-se um método para determinação de 1-nitropireno em material particulado proveniente da queima de cana-de-açúcar. O método inclui a redução do grupo nitro a amino, com posterior determinação por HPLC/fluorescência. O método proposto tem limite de detecção de 0,930ng mL-1 e limite de determinação de 1,250ng mL-1, apresentando recuperação entre 77,00 e 86,34%, para 5,00 e 50,00ng mL-1 respectivamente. / Abstract: Nitrated Polycyclic Aromatic Hydrocarbons (NPAHs) are the class of aromatic compounds with at least one nitro group (-NO2) enhanced to aromatic chain of a Polycyclic Aromatic Hydrocarbon (PAH). In 70's the discovery of mutagenic properties of these compounds present in atmospheric particulate matter and in gas exhaust of diesel motors are increased the scientific interess on occurrence of NPAHs into environment. These compounds, as PAHs, are associated with combustion sources as automobiles; harming systems (biomass and combustible based); burning of biomass (cigarette, florest, agricultural cultures, etc), because this they have a ubicous dissemination on environment. NPAHs are product of reaction of PAHs with nitrogen oxides on atmosphere, and they are present there at very low concentrations. The analysis of NPAHs in atmospheric samples is very difficult, because of artefacts of sampling process and PAH and other compounds interference on analytical determination. Because this, investigation of alternative methods sensitive and selective is necessary for NPAHs determination in atmospheric samples. In this work is studied a method for determination of 1-nitropyrene from particulate matter of sugar cane burning. The method include reduction of nitro group to amino, and analysis by HPLC/ Fluorescence. The proposed method has detection limit of 0, 930ng mL-1 and quantification limit of .1,250ng mL-1 showing recovery ranged between 77,00 and 86,34% for concentrations of 5,00 and 50,00ng mL-1, respectively. / Mestre
36

Sistema de estresse e uso de substâncias : efeito de polimorfismos no gene CRHR1 nas dependências de crack e nicotina

Bertuzzi, Guilherme Pinto January 2013 (has links)
Os Transtornos por Uso de Substâncias (TUS) são propostos pela Associação Norte-Americana de Psiquiatria e englobam diversas dependências químicas, incluindo o tabagismo e a dependência de crack. O uso de crack tem aumentado consideravelmente nos últimos anos, segundo dados de levantamentos brasileiros e mundiais. Com mecanismo de ação semelhante ao da cocaína, porém com efeito mais rápido, o crack é uma droga que causa grave prejuízo a seus usuários e conduz à dependência em pouco tempo. O tabagismo também é uma condição bastante prevalente no mundo inteiro, sendo que os prejuízos relacionados a esse transtorno envolvem principalmente o desenvolvimento de doenças respiratórias e câncer. Diversos trabalhos têm buscado identificar fatores de suscetibilidade a esses transtornos, sendo que estudos de associação envolvendo genes do sistema de resposta a estresse vêm ganhando importância. O eixo Hipotálamo- Pituitária-Adrenal (HPA) é o sistema de resposta a estresse mais conhecido em humanos e alvo do presente trabalho, uma vez que o funcionamento dessa cascata de sinalização da produção de cortisol pode desempenhar um papel relevante no desenvolvimento de psicopatologias. Além disso, o eixo HPA pode ser considerado um mediador da relação entre situações adversas na infância e o surgimento de TUS. O objetivo desse trabalho, portanto, é investigar o papel de polimorfismos no gene CRHR1 (que codifica o receptor tipo 1 do hormônio liberador de corticotrofina – CRH, hormônio inicial do eixo HPA) sobre o desenvolvimento e características clínicas da dependência química. Para isso, foram realizados dois estudos, envolvendo amostras de mulheres. No primeiro artigo, a partir de três amostras – (1) 136 usuárias de crack, (2) 55 tabagistas e (3) 262 voluntárias saudáveis – foram identificadas diferenças de freqüências alélicas e genotípicas do SNP rs12944712; além disso, a análise de haplótipos envolvendo tal SNP e o rs110402 revelou maior frequência do haplótipo contendo o alelo G nos dois polimorfismos nos grupos de usuárias de crack e tabagistas. No segundo artigo, foi avaliado o efeito da interação geneambiente envolvendo os mesmos polimorfismos e situações adversas na infância – estimada pela escala Childhood Trauma Questionnaire (CTQ) –sobre características clínicas da amostra de usuárias de crack, como craving e gravidade da dependência – estimados, respectivamente, pelas escalas Cocaine Selective Severity Assessment (CSSA) e Addiction Severity Index (ASI6). A análise não revelou uma interação significativa. A presente dissertação, portanto, revela um efeito do gene CRHR1 sobre o desenvolvimento de TUS, embora esse efeito pareça não se manifestar sobre a gravidade. Mais estudos são necessários visando esclarecer o real efeito do gene e do eixo HPA como um todo sobre os fenótipos e comportamentos aditivos, bem como os mecanismos subjacentes a essa relação. / The Substance Use Disorders (SUD) are proposed by the American Psychiatric Association and comprise several addictions, including tobacco and crack cocaine smoking. The prevalence of crack cocaine dependence has grown considerably, according to survey data from Brazil and worldwide. With mechanism of action similar to cocaine but with faster effect, crack is a drug that causes severe impairments to its users and leads to dependence in a short time. Tobacco smoking is also a highly prevalent condition worldwide, and the impact related to this disorder includes cancer and respiratory diseases. Several studies have attempted the identification of susceptibility factors to these disorders, and association studies involving stress response system genes have been performed. The Hypothalamic-Pituitary-Adrenal (HPA) axis is the best known stress response system, and the signaling cascade production of cortisol may play a role in the development of psychopathology. In addition, HPA axis can be considered a mediator of the relationship between early life adversity and SUD. The aim of this study is to investigate the role of polymorphisms in CRHR1 gene (encoding the corticotrophin releasing factor – CRH – receptor type 1, an initial factor in HPA axis response) on the development and clinical traits of drug dependence. Two studies were conducted on women samples. In the first article, three groups were compared - (1) 136 crack smokers, (2) 55 tobacco smokers and (3) 262 healthy volunteers. Differences in allele and genotype frequencies of the SNP rs12944712 were identified; in addition, the haplotype analysis involving this SNP and rs110402 revealed a higher frequency of the haplotype containing G allele in both polymorphisms in the groups of nicotine dependents and crack smokers. In the second article, we evaluated the effect of a gene-environment interaction involving the same polymorphisms and childhood adversity - estimated by Childhood Trauma Questionnaire (CTQ) scale – on clinical characteristics of the sample of crack users, such as craving and severity of dependence - estimated respectively by the Cocaine Selective Severity Assessment (CSSA) and Addiction Severity Index (ASI6) scales. The analysis did not reveal a significant interaction. This dissertation thus shows an effect of CRHR1 genepolymorphism on the development of SUD, although this effect does not seem to impact disorder severity. More studies are needed in order to clarify the actual effect of the gene and of the HPA axis as a whole on addictive behaviors.
37

Regulation of murine corticotroph cell excitability

Duncan, Peter James January 2014 (has links)
Corticotroph cells from the anterior pituitary are an integral component of the hypothalamic-pituitary-adrenal (HPA) axis, which controls the neuroendocrine response to stress. Following stressful stimuli, corticotrophin-releasing hormone (CRH) and arginine vasopressin (AVP) from the hypothalamus act synergistically to stimulate adrenocortiotrophin hormone (ACTH) secretion from corticotroph cells. ACTH is released into the circulation where it stimulates the secretion of glucocorticoids from the adrenal cortex. The HPA axis is kept in fine balance through an elegant negative feedback system where elevation of plasma glucocorticoids results in inhibition at the level of both the pituitary and the hypothalamus. During acute stress, glucocorticoids can be beneficial however chronic elevation of glucocorticoids can have many adverse effects on health. Corticotroph cells are electrically excitable and have been shown to fire single-spike action potentials as well as complex bursting patterns. Stimulation of corticotrophs with physiological concentrations of CRH/AVP results in a robust increase in firing frequency and a transition from spiking to bursting. Intracellular Ca2+ increases to a greater extent during bursting which has been proposed to drive hormone secretion. There is evidence to suggest that large conductance calcium- and voltage-gated potassium (BK) channels promote bursting behaviour in anterior pituitary cells. Glucocorticoids have been shown to regulate ACTH secretion and also modulate BK channel activity. However, the effects of glucocorticoids on native corticotroph excitability are currently unknown. The aim of this study was to first characterise the electrical properties of corticotrophs under basal conditions and following exposure to CRH/AVP. Secondly, to investigate the regulation of corticotroph excitability by glucocorticoids. Finally, establish the role of the BK channel in regulating bursting behaviour and CORT regulation in corticotroph cells. Corticotroph cells were acutely isolated by trypsin digestion from mice aged 2-5 months constitutively expressing GFP under control of the POMC promoter (POMC-GFP). Mice used for pituitary cell culture were male unless otherwise stated. Cells were maintained in a serum free media and electrophysiological recordings obtained 24-96 hours post-isolation. Current clamp recordings were obtained from corticotrophs using the perforated patch technique. Although spontaneous activity of corticotroph cells was variable, they displayed predominantly single-spike action potentials under basal conditions. Stimulation with physiological concentrations of CRH and AVP (0.2 nM and 2 nM respectively) resulted in a membrane depolarisation accompanied by an increase in firing frequency and a transition to bursting. Individually, CRH and AVP were able to increase corticotroph excitability. However, only CRH was able to drive an increase in bursting suggesting that bursting is primarily regulated through the cAMP/PKA pathway. Experiments were performed to investigate the modulation of corticotroph activity by glucocorticoid negative feedback. Acute exposure (< 10 min) to corticosterone resulted in a decrease in spontaneous activity as well as shortening the response to CRH/AVP. Pretreatment of corticotrophs with 100 nM corticosterone (90 min) resulted in a membrane hyperpolarisation and a decrease in spontaneous firing frequency. Following corticosterone pretreatment, CRH/AVP failed to induce a significant transition from spiking to bursting. Increasing the pretreatment time to 150 minutes resulted in a further suppression of both spontaneous and CRH/AVPevoked activity. Fast activation of BK channels during the upstroke of an action potential has been proposed to promote bursting behaviour in other pituitary cells. Corticotrophs treated with a BK channel blocker (1 μM paxilline) or isolated from BK-/- mice showed no significant difference in basal activity but displayed a reduction in CRH/AVPevoked bursting activity. In both cases, bursting was significantly reduced but not completely abolished. Corticosterone treatment of BK-/- cells resulted in a further decrease in both firing frequency and bursting behaviour. Taken together, these results suggest that although BK channels play an important role in bursting, they are not the only component. Comparisons of male and female corticotrophs revealed subtle differences in their properties. Following CRH/AVP stimulation, male cells displayed a high degree of bursting activity whereas female cells exhibited predominantly an increase in singlespike action potential frequency. Treatment of female corticotrophs with corticosterone (150 min) resulted in a significant reduction in firing frequency but no measurable change in bursting behaviour. BK-/- cells from female mice showed no difference in bursting activity following CRH/AVP compared to wild types. This data suggests that modulation of firing frequency is the more important component in female corticotroph cells. In conclusion, CRH/AVP is proposed to drive ACTH secretion in male corticotroph cells through an increase in bursting activity. Corticosterone pretreatment suppresses both spontaneous and CRH/AVP-evoked activity. It is possible that corticosterone regulates corticotroph excitability through two mechanisms. Corticosterone suppresses bursting activity following CRH/AVP stimulation through multiple targets which might include the BK channel. Additionally, corticosterone reduces firing frequency through a mechanism independent of BK channels. It is important to further characterise the physiology of corticotroph cells and how ACTH secretion is regulated through their electrical excitability. This would lead to a greater understanding of the role of corticotrophs in the HPA axis. Further study of corticotrophs could potentially lead to pharmacological manipulation of the stress response and novel treatments for stress-related disorders.
38

Avaliação de HPAs nas águas subterrâneas e superficiais da área de instalação do Reator Multipropósito Brasileiro - RMB / Evaluation of PAHs in the groundwater and surface waters of the Brazilian\'s Multipurpose Reactor installation area

Pereira, Karoline de Paula 13 May 2019 (has links)
As atividades a serem realizadas na área do empreendimento RMB (Reator Multipropósito Brasileiro), cujas instalações e infraestrutura agregadas serão localizadas no estado de São Paulo, no município de Iperó, podem envolver a liberação de efluentes para o meio ambiente, seja de forma controlada ou não, do mesmo modo que qualquer outra instalação. Os hidrocarbonetos policíclicos aromáticos (HPAs) estudados neste trabalho apresentam comportamento ubíquo, são considerados compostos químicos com alta toxicidade, persistência no meio ambiente, potencial bioacumulativo e forte tendência de se biomagnificar. O objetivo desse trabalho foi determinar 14 dos 16 HPAs majoritários, classificados pela USEPA, nas amostras de águas superficiais e subterrâneas da área de instalação do RMB e seu entorno. Foram avaliados quatro períodos distintos utilizando uma metodologia já desenvolvida e validada por Brito (2009). Foi verificado o cenário atual em relação às concentrações dos HPAs nas águas da região que será construído o empreendimento, RMB, fornecendo uma visão geral do grau de contaminação ou não dos corpos hídricos, o que contribuirá com um banco de dados para pesquisas futuras. Paralelamente, foi validado e aplicado um método analítico já existente para avaliação de HPAs nos sólidos suspensos da coluna d\'água das amostras coletadas. A avaliação preliminar da área estudada demonstrou que o local do projeto RMB é preservado, mas alguns corpos d\'água ao redor da área, como o rio Sorocaba, apresentam concentrações significativas de HPAs, provavelmente em razão das atividades antropogênicas no entorno, indicando que a área precisa de uma maior atenção. Utilizando a técnica analítica de HPLC com detecção UV/vis, foram quantificados compostos como Acenaftileno Fluoreno e Fenantreno acima do valor legislado nas amostras de água. Foram observadas baixas concentrações de praticamente todos os compostos estudados no material em suspensão e alguns compostos como Fluoreno, Acenafteno, Acenaftileno e Benzo[b]fluoranteno, em concentrações mais altas, é necessário um programa de monitoramento constante, para que a partir dos dados obtidos, possa-se tomar decisões concisas de controle. / The activities to be carried out in the area of the RMB (Brazilian Multipurpose Reactor) project, whose aggregate facilities and infrastructure will be located in the state of São Paulo, in the municipality of Iperó, may release effluents into the environment, either in a controlled or not in the same way as any other installation. The polycyclic aromatic hydrocarbons (PAHs) studied in this work are ubiquitous and considered chemical compounds with high toxicity, persistence in the environment, bio accumulative potential and strong tendency to bio magnify. The objective of this study was to determine 14 of the 16 major PAHs, classified by the USEPA, in the surface and groundwater samples of the RMB installation area and its surroundings. Four distinct periods were evaluated using a methodology already developed and validated. The current scenario was verified regarding the PAHs concentrations in the waters of the region that will be built the RMB, providing an overview of the degree of contamination of the water bodies, which will contribute to a database for future research. At the same time, an analytical method was validated and applied to evaluate PAHs in the suspended solids of the water column of the collected samples. The preliminary evaluation of the studied area demonstrated that the site of the RMB project is preserved, but some water bodies around the area, such as the Sorocaba River, present significant concentrations of PAHs, probably due to the anthropogenic activities in the surroundings, indicating that the area needs more attention. Using the analytical HPLC technique with UV/vis detection, compounds such as acenaphthylene, fluorene and phenanthrene were quantified above the legislated value in the water samples. Although low concentrations of practically all compounds studied in the suspended material have been observed and some compounds such as fluorene, acenaphthene, acenaphthylene, and benzo[b]fluoranthene at high concentrations, a constant monitoring program is required to that from the data obtained, one can make concise decisions of command and control.
39

Effects of Acute Periods of Prenatal Stress on Behaviour and Endocrine Function in Guinea Pigs

Kapoor, Amita 26 February 2009 (has links)
Epidemiological studies in humans have revealed a relationship between altered development in utero and an increased incidence of pathophysiology during postnatal life. One of the mechanisms underlying this relationship is thought to be exposure to excess glucocorticoids during critical phases of brain development. The aim of the current set of studies was to determine the effects of prenatal stress during discrete developmental windows on behaviour and endocrine function in male and female guinea pig offspring. Guinea pigs were used as the model for these studies as they are a long-gestation species that give birth to neuroanatomically mature young and fetal brain development is well characterized. Pregnant guinea pigs were exposed to a high frequency strobe light during the period of rapid fetal brain growth or the period of rapid brain myelination. Pregnant guinea pigs were allowed to deliver normally and guinea pig offspring were tested for ambulatory activity, anxiety and hypothalamic-pituitary-adrenal (HPA) axis function. Male offspring whose mothers were exposed to stress during the period of rapid brain growth exhibited increased anxiety behaviour, increased basal plasma cortisol levels and decreased plasma testosterone levels. We found that replacing testosterone in these animals reversed the behavioural and endocrine differences. Male offspring whose mothers were exposed to stress during the period of rapid myelination exhibited an increased plasma cortisol response to activation of the HPA axis. Female offspring whose mothers were exposed to stress during the period of rapid brain myelination exhibited decreased ambulatory activity and a blunted salivary cortisol response to the stress of the strobe light, but only during the estrous phase of the reproductive cycle. Therefore, the current set of studies has demonstrated the effects of prenatal stress on behaviour and HPA axis activity are dependent on; 1) the timing of the prenatal stress and 2) the hypothalamic-pituitary-gonadal axis in both male and female offspring. These studies have begun to uncover the mechanisms underlying programming and provide the basis for continuing research in humans.
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The Neuroendocrinology of Seasonal Aggression in Female Syrian Hamsters

Gutzler, Stephanie 28 July 2009 (has links)
Aggression is a feature of many clinical disorders including autism, Alzheimer’s disease, bipolar disorder, and schizophrenia. The available treatment options act to prevent impulsive aggression through modulation of GABAergic and dopaminergic pathways which come with metabolic and dyskinetic side effects. The mechanism underlying aggressive motivation, however, has not been elucidated. In addition, previous studies have been heavily biased towards males of various species. Mimicking changes in day length, or photoperiod, in the laboratory is a natural manipulation used to examine seasonal changes in aggressive behavior in many species. In response to the reduction in the duration of light exposure, animals undergo gonadal regression and become reproductively quiescent. During this non-breeding season in male photoperiod-responsive animals, aggressive behavior increases significantly. Although studies have shown offensive aggression remains elevated in female rodents, seasonal regulation of this behavior in females has not been thoroughly studied. The neuropeptide arginine-vasopressin (AVP) has been implicated in the facilitation of aggressive behavior in male rodents and fishes; therefore, it is useful to examine AVP as a modulator of seasonal aggression in females. Because the actions of AVP in female social behavior may be hormonally-dependent, we investigated the hormonal mechanisms that regulate the expression of AVP receptors and the behavioral actions of AVP on aggression. In addition to changes in gonadal steroid hormones during the non-breeding season, we identified photoperiod-dependent alterations in adrenal hormone secretion as AVP plays a role in regulation of hypothalamic-pituitary-adrenal axis (HPA) activity and anxiety-like behaviors in animal models.

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