236 research outputs found

    Ensuring successful introduction of Wolbachia in natural populations of Aedes aegypti by means of feedback control

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    The control of the spread of dengue fever by introduction of the intracellular parasitic bacterium Wolbachia in populations of the vector Aedes aegypti, is presently one of the most promising tools for eliminating dengue, in the absence of an efficient vaccine. The success of this operation requires locally careful planning to determine the adequate number of individuals carrying the Wolbachia parasite that need to be introduced into the natural population. The introduced mosquitoes are expected to eventually replace the Wolbachia-free population and guarantee permanent protection against the transmission of dengue to human. In this study, we propose and analyze a model describing the fundamental aspects of the competition between mosquitoes carrying Wolbachia and mosquitoes free of the parasite. We then use feedback control techniques to devise an introduction protocol which is proved to guarantee that the population converges to a stable equilibrium where the totality of mosquitoes carry Wolbachia.Comment: 24 pages, 5 figure

    Antimicrobial activity of Alternanthera brasiliana Kuntze (Amaranthaceae): a biomonitored study

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    In an attempt to identify new antimicrobial compounds with potential to be used as a bactericidal/ fungicidal agent, a biomonitored study of extracts of Alternanthera brasiliana, which is used in Brazilian folk medicine as bactericidal, analgesic and anti-inflammatory, was developed. Different techniques of evaluation have been used in the partitioned extracts of the antimicrobial activity associated with chromatographic methodologies. The work led to the isolation of two substances in the ethyl acetate extract, identified as quercetin and sitosterol glycoside and the antibacterial evaluation of these substances demonstrated that the flavonoid presented antibacterial action against S. aureus. Further studies intend to identify new substances with antibacterial activity in extracts of A. brasiliana.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    HISTÓRICO DA COMPOSIÇÃO DA VEGETAÇÃO ARBÓREA DO PARQUE DO IBIRAPUERA E SUA CONTRIBUIÇÃO PARA A CONSERVAÇÃO DA BIODIVERSIDADE

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    Os parques urbanos, além de importantes espaços de recreação, esportes, lazer, cultura e promover melhoria na qualidade de vida, apresentam potencial de contribuir para a biodiversidade regional. Objetivou-se discutir as modificações históricas da composição da vegetação arbórea do Parque Ibirapuera de São Paulo, SP; sua contribuição para a conservação da biodiversidade regional; e analisar as espécies arbóreas do Parque quanto ao risco de queda. Para isso, foi elaborado inventário por censo dos indivíduos arbóreos do Parque Ibirapuera. Historicamente as primeiras vegetações inseridas no Parque possuíam o papel de promover a drenagem da área com o uso de espécies arbóreas exóticas, como as do gênero Eucalyptus e Ligustrum, que hoje representam 16% e 7,29% das árvores, respectivamente. Estas representaram a maior porcentagem de espécies classificadas em risco de queda alto, 83,7%. A inserção posterior de espécies nativas no Parque contribuiu para o aumento da biodiversidade regional, atualmente apresentando 39,4% de árvores nativas brasileiras. Os resultados indicam a necessidade da contínua diversificação de árvores e arbustos com espécies nativas, pois além de contribuir para a minimização de pragas e doenças vegetais, pela manutenção da diversidade e dos processos ecológicos na paisagem urbana, poderá prevenir fatores importantes que provocam a queda de árvores

    The effect of continuous positive airway pressure on blood pressure in patients with obstructive sleep apnea and uncontrolled hypertension : study design and challenges during the COVID-19 pandemic

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    OBJECTIVES: To describe the MORPHEOS (Morbidity in patients with uncontrolled HTN and OSA) trial, and describe the challenges imposed by the COVID-19 pandemic. METHODS: MORPHEOS is a multicenter (n=6) randomized controlled trial designed to evaluate the blood pressure (BP) lowering effects of treatment with continuous positive airway pressure (CPAP) or placebo (nasal strips) for 6 months in adult patients with uncontrolled hypertension (HTN) and moderate-to-severe obstructive sleep apnea (OSA). Patients using at least one antihypertensive medication were included. Uncontrolled HTN was confirmed by at least one abnormal parameter in the 24-hour ABPM and >= 80% medication adherence evaluated by pill counting after the run-in period. OSA was defined by an apnea-hypopnea index >= 15 events/ hours. The co-primary endpoints are brachial BP (office and ambulatory BP monitoring, ABPM) and central BP. Secondary outcomes include hypertension-mediated organ damage (HMOD) to heart, aorta, eye, and kidney. We pre-specified several sub-studies from this investigation. Visits occur once a week in the first month and once a month thereafter. The programmed sample size was 176 patients but the pandemic prevented this final target. A post-hoc power analysis will be calculated from the final sample. ClinicalTrials.gov: NCT02270658. RESULTS: The first 100 patients are predominantly males (n=69), age: 52±10 years, body mass index: 32.7±3.9 kg/m2 with frequent co-morbidities. CONCLUSIONS: The MORPHEOS trial has a unique study design including a run-in period; pill counting, and detailed analysis of hypertension-mediated organ damage in patients with uncontrolled HTN that will allow clarification of the impact of OSA treatment with CPAP

    INTOXICAÇÃO NATURAL DE BOVINOS LEITEIROS POR Cestrum laevigatum (SOLANACEAE) NO AGRESTE DE PERNAMBUCO – BRASIL

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    The aim of the present study was to report an outbreak of natural poisoning by Cestrum laevigatum in dairy cattle in the “Agreste” region of Pernambuco state, Brazil. Epidemiological and clinical data were collected. Among a lot of 60 cows, eight became ill and four died. Two cows underwent necropsy, during which fragments of the central nervous system, liver, gall bladder, spleen and kidney were collected for histopathlogical analysis. Blood samples were collected for hematological and biochemical tests. The animals exhibited apathy, muscle tremors, reduced appetite, different degrees of dehydration and compromised reticulorumen dynamics as well as a small quantity of dry feces with the presence of mucus and blood. The laboratory exams revealed an increase in serum activity of aspartate aminotransferase and gamma glutamyltransferase as well as hypoalbuminemia. The necropsy revealed an enlarged liver and cutting surface with a nutmeg aspect as well as areas of hemorrhaging in the heart, trachea, abomasum, spleen, intestine and bladder. The microscopic analysis revealed centrilobular hepatic necrosis associated to accentuated hemorrhaging. These findings characterized poisoning by Cestrum laevigatum and led to the adoption of control and prevention measures

    Ferramentas para a caracterização de painéis fotovoltaicos

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    Neste trabajo apresentamos procedimientos y herramientas para la caracterización completa de paneles fotovoltaicos. Como punto de partida, fueron obtenidas las curvas caracteristicas provenidas por el fabricante. En un segundo momento fueron hechas coletas manuales de dados para la confección de las curvas caracteristicas. A partir de las propriedades fisicas de semiconductores el modelamento del panel fue establecido. El procedimiento establecido és muy fatigoso y reiterativo, podendo llevar a imprecisiones. Para la automatización deste procedimiento, lo siguiente sistema fue proyectado y montado: un conversor dc/dc permite realizar el control electronico de carga resistiva; un computadora realiza el control cíclico de la variación de carga del panel. Un sistema de aquisición de dados permite la obtención de los parámetros en el panel. A partir desta coleta de dados automatizada un software constroe las curvas caracteristicas.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

    Brazilian Morus nigra

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    Morus nigra has been used popularly for several proposes, including diabetic. In an attempt to support medicinal value, the acute hypoglycemic, hypolipidemic, and antioxidant effects of the ethanolic extract of Morus nigra (EEMn 200 or 400 mg/kg b.w.) were evaluated in normal and alloxan-induced diabetic treated for 14 days. Serum biochemical and antioxidant analysis were performed at the end of experiment. Oral glucose tolerance test was performed at 10th and 15th days. Chromatographic analysis by HPLC-DAD of EEMn was performed. Insulin was used as positive control to glycemic metabolism as well as fenofibrate to lipid metabolism. EEMn (400 mg/kg/day) reduced fasting and postprandial glycaemia, improved oral glucose tolerance, and reduced lipolysis and proteolysis in diabetic rats. EEMn decreased the blood levels of total cholesterol and increased HDL level when compared to the diabetic control rats. At higher levels, EEMn reduced triglycerides and VLDL levels in diabetic rats. Also, EEMn reduced malondialdehyde and increased the reduced glutathione levels in liver of diabetic rats. Chromatographic analysis identified the presence of the flavonoids rutin, isoquercetin, and kaempferitrin. Acute EEMn treatment reduced hyperglycemia, improved oral glucose tolerance, and minimized dyslipidemia and oxidative stress leading to a reduction in atherogenic index in alloxan-induced diabetic rats
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