41 resultados para Ramón Sender


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In the present study, an extensive in vitro antimicrobial profiling was performed for three medicinal plants grown in Cuba, namely Simarouba glauca, Melaleuca leucadendron and Artemisia absinthium. Ethanol extracts were tested for their antiprotozoal potential against Trypanosoma b. brucei, Trypanosoma cruzi, Leishmania infantum and Plasmodium falciparum. Antifungal activities were evaluated against Microsporum canis and Candida albicans whereas Escherichia coli and Staphylococcus aureus were used as test organisms for antibacterial activity. Cytotoxicity was assessed against human MRC-5 cells. Only M. leucadendron extract showed selective activity against microorganisms tested. Although S. glauca exhibited strong activity against all protozoa, it must be considered non-specific. The value of integrated evaluation of extracts with particular reference to selectivity is discussed.

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Leishmaniasis is one of the most important parasitic infections, but current treatments are unsatisfactory due to their toxicity, cost and resistance. Therefore, the development of new antileishmanial compounds is imperative. Many people who live in endemic areas use plants as an alternative to treat the disease. In this paper, we characterised the essential oil from Piper auritum, evaluated its cytotoxicity and determined its antileishmanial activity. The chromatogram obtained by gas chromatography revealed 60 peaks and we found that safrole was the most abundant compound, composing 87% of the oil. The oil was active against the promastigotes of Leishmania major, Leishmania mexicana, Leishmania braziliensis and Leishmania donovani with a favourable selectivity index against peritoneal macrophages from BALB/c mice. The Piper-oil inhibited the growing of intracellular amastigotes of L. donovani with an IC50 value of 22.3 ± 1.8 μg/mL. This study demonstrates the usefulness of the essential oils as a promising alternative to treat leishmaniasis.

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The activity of five (1-5) abietane phenol derivatives against Leishmania infantum and Leishmania braziliensis was studied using promastigotes and axenic and intracellular amastigotes. Infectivity and cytotoxicity tests were performed with J774.2 macrophage cells using Glucantime as a reference drug. The mechanisms of action were analysed by performing metabolite excretion and transmission electron microscopy ultrastructural studies. Compounds 1-5 were more active and less toxic than Glucantime. The infection rates and mean number of parasites per cell observed in amastigote experiments showed that derivatives 2, 4 and 5 were the most effective against both L. infantum and L. braziliensis. The ultrastructural changes observed in the treated promastigote forms confirmed that the greatest cell damage was caused by the most active compound (4). Only compound 5 caused changes in the nature and amounts of catabolites excreted by the parasites, as measured by ¹H nuclear magnetic resonance spectroscopy. All of the assayed compounds were active against the two Leishmania species in vitro and were less toxic in mammalian cells than the reference drug.

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The aim of this work was to identify the natural breeding sites of sandflies in the province of Chaco, Argentina, for the first time. Preliminary studies were conducted in two different phytogeographic regions: dry Chaco (Parque Provincial Pampa del Indio), in January 2010, and humid Chaco (Resistencia, Margarita Belén and Colonia Benítez), from May-September 2010. A total of 127 samples were collected (Pampa del Indio: 15, Resistencia: 37, Margarita Belén: 36, Colonia Benítez: 39). A female of Migonemyia migonei was found in Pampa del Indio at the base of a bromeliad in the summer (January) and a pupal exuvium of a phlebotomine fly was found in Resistencia, in a place where dogs rested, in the winter (July). These findings highlighted these two sites as potential breeding sites. Because the existence of potential natural breeding sites for sandflies has been demonstrated in both forest and periurban areas, expanding the search efforts and characterising these sites will enable the development of specific study designs to gain insight into the spatial distribution of the risks posed by these vectors. The resulting information will serve as a basis for proposing and evaluating vector control measures.

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Lutzomyia longipalpis was recorded for the first time in Argentina in 2004, in the province of Formosa. In the following years, the vector spread to the south and west in the country and was recorded in the province of Chaco in 2010. From November 2010-May 2012, captures of Phlebotominae were made in the city of Resistencia and its surroundings, to monitor the spread and possible colonisation of Lu. longipalpis in the province of Chaco. In this monitoring, Lu. longipalpis was absent in urban sampling sites and its presence was restricted to Barrio de los Pescadores. This suggests that the incipient colonisation observed in 2010 was not followed by continuous installation of vector populations and expansion of their spatial distribution as in other urban centres of Argentina.

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We report the presence of the competent vector for Leishmaniaspp, Migonemyia migonei, and theEvandromyia cortelezzii-sallesi complex south of its known distribution in the central temperate region of Argentina, in the province of Córdoba. The persistence of this phlebotomine in the northern border of the province, its association with a case of cutaneous leishmaniasis, and the new record in the outskirts of the city of Córdoba, the second most populated in the country, strengthens the need for regular vector surveillance and a case detection-sensitive health system in vulnerable regions, even in temperate climates.

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Apresenta um serviço de resumos nas áreas de Ciência da Informação e Biblioteconomia, formatado a partir do Sistema Eletrônico de Editoração de Revistas (Seer), tecnologia de publicação eletrônica traduzido e customizado pelo Instituto Brasileiro de Informação em Ciência e Tecnologia (Ibict). Resume os dados sobre as revistas brasileiras que adotaram a tecnologia de editoração do Seer, bem como sobre o conteúdo dos números publicados da revista Pesquisa Brasileira em Ciência da Informação e Biblioteconomia (PBCIB).

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O trabalho objetivou determinar a composição corporal de cordeiros Santa Inês e estimar suas exigências de magnésio, potássio e sódio, para ganho de peso. Foram conduzidos dois experimentos com 18 cordeiros machos em cada um, com peso médio inicial de 25 e 15 kg no primeiro e no segundo experimentos, respectivamente. Em cada experimento, seis animais foram abatidos, para determinação das quantidades de cada mineral retido no corpo, servindo como animais-referência para a técnica do abate comparativo. Os doze animais remanescentes em cada experimento foram divididos em dois grupos: seis animais receberam alimentação ad libitum e seis receberam alimentação restrita. Os cordeiros do grupo ad libitum e restrito foram abatidos quando os do grupo ad libitum atingiram 35 e 25 kg de peso vivo no primeiro e segundo experimentos, respectivamente. A composição corporal em Ca, P, Mg, K e Na foi estimada a partir de equações de regressão do logaritmo da quantidade desses minerais presentes no corpo vazio dos animais, em razão do peso corporal vazio. As exigências líquidas desses minerais por kg de ganho de peso vivo, obtidas a partir da derivação das equações de predição da composição corporal foram: 0,47 e 0,41 g de Mg, 2,32 e 2,05 g de K e 1,33 e 0,55 g de Na, respectivamente, em animais com 15 e 35 kg.

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Dois experimentos foram conduzidos com o objetivo de determinar a composição corporal e estimar as exigências de Ca e P, para ganho em peso, de cordeiros Santa Inês em crescimento. Em cada experimento foram usados 18 animais com 25 a 35 kg de peso vivo (PV), no primeiro, e com 15 a 25 kg no segundo experimento. Seis animais foram abatidos no início de cada experimento para avaliar o conteúdo de Ca e P corporal, servindo como animais referência para o método do abate comparativo, seis animais receberam alimentação ad libitum e seis, alimentação restrita. As exigências líquidas de Ca e P para o ganho em peso foram estimadas a partir da derivação de equações de regressão do logaritmo da quantidade desses minerais presentes no corpo vazio, em função do peso do corpo vazio. As exigências líquidas por quilo de ganho de PV para animais com 15, 25 e 35 kg de PV foram, respectivamente: 11,63, 10,52 e 9,82 g de Ca e 5,82, 4,99 e 4,28 g de P.

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El objetivo de este trabajo fue evaluar la influencia de la fertilización mineral nitrogenada, después de la poda del cafeto robusta, sobre la productividad del cultivo y algunos indicadores químicos (pH, materia orgánica) y microbiológicos (respiración biológica y nitrificación) de dos Cambisoles en Tercer Frente, Santiago de Cuba y La Alcarraza, Holguín, durante los años 2003-2007. Se estudió la respuesta a dosis crecientes de nitrógeno (0 hasta 400 kg ha-1), en presencia de un fondo fijo de P (50 kg ha-1) y K (160 kg ha-1), en un diseño experimental de bloques al azar, con cuatro réplicas. Para productividades entre 0,50 y 0,84 Mg ha-1 de café, son suficientes 75 kg ha-1 de N. Aplicaciones de 100 kg ha-1 de N permitieron productividades de 1,22 a 1,25 Mg ha-1de café. Con dosis de 153 kg ha-1 de N, se logran producciones de 1,80 Mg ha-1 de café, mientras que para productividades superiores a 2 Mg ha-1 se necesita aplicar 200 kg ha-1 en ambos suelos. Se encontró un incremento importante en las productividades del cafeto por cada quilogramo de N aplicado, que osciló entre 2,13 y 7,80. Las dosis propuestas por sitio no afectaron la actividad microbiana y la materia orgánica de los suelos. Se encontró disminución del pH del suelo respecto a su estado inicial.

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A goiaba é um fruto muito perecível. Assim, objetivou-se avaliar os efeitos de ceras à base de carnaúba na conservação pós-colheita de goiabas Pedro Sato sob condição ambiente. Utilizaram-se cinco ceras comerciais: Citrosol AK (18%), Citrosol M (10%), Fruit wax (18 a 21%), Meghwax ECF-100 (30%) e Cleantex wax (18,5 a 20,5%), as quais foram aplicadas manualmente, na proporção de 0,15 a 0,20mL por fruta. Frutas sem aplicação de cera foram utilizadas como controle. O delineamento experimental foi inteiramente casualizado com 6 tratamentos, 4 repetições e 5 frutas por parcela. As goiabas foram caracterizadas imediatamente após a colheita e avaliadas aos 2, 4 e 6 dias após a aplicação dos tratamentos. As ceras exerceram pouca influência nos teores de sólidos solúveis totais, acidez total titulável e ácido ascórbico, porém, foram eficientes em retardar o amadurecimento, reduzir a perda de massa e a incidência de podridões. A cera Meghwax ECF-100 apresenta potencial para utilização em goiabas, porém há necessidade de ser avaliada em maior diluição, para evitar alterações indesejáveis.

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Se realizó un muestreo en una red regular de 31 puntos ubicados con GPS y con base en análisis geoestadísticos, se estudió la variabilidad espacial de algunas propiedades del suelo y de la topografía con el fin de establecer su incidencia en el rendimiento de un cultivo de mango. Las propiedades edáficas y el rendimiento presentaron un patrón de distribución espacial que varía de manera considerable dentro del lote. El rango de los modelos de semivarianza ajustados varió entre 10 y 192 metros. Con excepción del pH y del Ca las relaciones efecto pepita/meseta fueron menores del 30%, es decir, que en general hay precisión en las predicciones debido a que los procesos espaciales considerados son explicados en su mayoría por la variación estructural. K, Ca, CIC, pendiente del terreno, relación Ca+Mg/K y altitud fueron las variables que mayor influencia tuvieron en el rendimiento. El método aplicado es útil para definir zonas de manejo dentro de los lotes y algunos criterios como la altitud y la pendiente son aplicables para zonificación de áreas mayores calculándolos a partir de un modelo digital de elevación.

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C11H11N3O4 , Mr = 249.23, triclinic, , a = 5.453(1), b = 22.873(5), c = 4.893(1) Å, a = 94.47(3), b = 96.36(3), g = 86.27(3)º, V = 603.7(8)ų,Z = 2, Dx = 1.371 Mg/m-3,l(Cu Ka1) = 1.54178Å, m = 0.86mm-1, room temperature. The crystal structure of N-isopropyl-2-cyano-3(5'-nitrofuryl) - acrylamide has been determined by Direct Methods and refined to R = 0.086 for 797 observed reflections. The molecules in the crystal are packed at normal van der Waals forces and by an hydrogen bond between N1-H1...02i (N1...02i: 2.910(1)Å), with i=x,y,z+1).

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Thermospray flame furnace Atomic Absorption Spectrometry (TS-FF-AAS) was used for the total determination of Cd, Pb and Zn in fresh water and seawater samples at µg L-1 levels, and in marine sediment samples at µg g-1 levels. Using a sample loop of 50 µL and a peristaltic pump the samples were transported into the metallic tube placed over an air/acetylene flame, through a ceramic capillary (o.d. = 3.2 mm) containing two parallel internal orifices (i.d = 0.5 mm). The detection limits determined for Cd, Pb and Zn using a synthetic water matrix (2.5% m/v NaCl, 0.5% m/v MgCl2 and 0.8% m/v CaCl2) were 0.32 µg L-1; 2.6 µg L-1 and 0.21 µg L-1 respectively. The methodology by TS-FF-AAS was validated by determination of Cd, Pb and Zn in certified reference materials of water and marine sediment, and the t-test for differences between means was applied. No statistically significant differences were established in fresh water and seawater (p>0.05), whereas differences became apparent in marine sediment (p<0.03).

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Trace metals (Cd, Cu, Pb and Zn) enrichment, availability and contamination in superficial sediments of three interconnected urban lagoons localized in Concepción-Chile, were evaluated. According to the results of geochemical fracctionation analysis, Cu and Pb are rather associated with oxi-hydroxides, Cd is associated with exchangeable and carbonates fraction, while Zn is mainly associated with organic, oxi-hydroxides and residual fraction. The estimation of the availability percentages indicate that Cu is the most mobile metal and the less mobile is the Cd. An evaluation of the geo-accumulation index and urban industrial pollution allowed to classify the studied zone as moderately to highly contaminated.