335 research outputs found

    Comparison of esters determination techniques in cachaça

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    An analytical comparison of three different techniques for quantitative profile of esters in cachaça is reported. The Ministério da Agricultura Pecuária e Abastecimento (MAPA) recommends the use of GC/FID or volumetry. Despite being laborious and lacking in chemical speciation, the volumetric technique for total ester content shows to be appropriate, reproducible, and accurate for the analysis of cachaça. However, the GC/FID suggested by MAPA, considering only ethyl acetate, shows inaccuracy, underestimating the total ester content by a median factor of 72%, mainly due to the absence of ethyl lactate analysis. On the other hand, the GC/MS technique that comprises the analysis and speciation of nine esters, including ethyl lactate, proved to be reproducible, simple, fast and accurate for the analysis of total ester content in cachaça. Thus, the total ester content results obtained using GC/FID must be considered with precaution.FAPESPCNP

    Mean-field model for a mixture of biaxial nematogens and dipolar nanoparticles

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    We analyze a mean-field model for mixtures involving biaxial nematogens and dipolar nanoparticles, taking into account orientational and isotropic pair interactions between nematogens, but also orientational nematogen-nanoparticle interactions. We determine bulk equilibrium phase diagrams for a wide range of interaction strengths, identifying in each case the effect of the nanoparticles on the stability of nematic phases and on the appearance of multicritical points. Special attention is given to the limit of low concentration of nanoparticles, in which their effect on the temperatures of both the first-order uniaxial-isotropic and the continuous biaxial-uniaxial transitions is investigated in detail

    Hidrogenionic potential (pH) of the attractant, trap density and control threshold for Ceratitis capitata (Diptera: tephritidae) on Hamlin oranges in São Paulo central region, Brazil

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    This study evaluated the effect of initial pH values of 4.5, 6.5 and 8.5 of the attractant (protein bait) Milhocina® and borax (sodium borate) in the feld, on the capture of fruit flies in McPhail traps, using 1, 2, 4 and 8 traps per hectare, in order to estimate control thresholds in a Hamlin orange grove in the central region of the state of São Paulo. The most abundant fruit fly species was Ceratitis capitata, comprising almost 99% of the fruit flies captured, of which 80% were females. The largest captures of C. capitata were found in traps baited with Milhocina® and borax at pH 8.5. Captures per trap for the four densities were similar, indicating that the population can be estimated with one trap per hectare in areas with high populations. It was found positive relationships between captures of C. capitata and the number of Hamlin oranges damaged, 2 and 3 weeks after capture. It was obtained equations that correlate captures and damage levels which can be used to estimate control thresholds. The average loss caused in Hamlin orange fruits by C. capitata was 2.5 tons per hectare or 7.5% of production.Esta pesquisa teve como objetivos: avaliar o efeito do pH inicial, 4.5; 6.5 e 8.5, do atrativo proteico Milhocina® e bórax (tetraborato de sódio) na captura de moscas-das-frutas em armadilhas McPhail; estudar densidades de armadilhas, 1; 2; 4 e 8 por hectare, para estimar níveis de controle em laranja cv. Hamlin, na região central de São Paulo. A espécie predominante, com 99% das moscas-das-frutas capturadas, foi Ceratitis capitata, sendo 80% de fêmeas. As maiores capturas de C. capitata ocorreram nas armadilhas com Milhocina® e bórax em pH 8.5. As capturas, nas 4 densidades, foram semelhantes, indicando que a população pode ser estimada com uma armadilha por hectare em áreas de altas populações. Houve relações positivas entre capturas de C. capitata e o número de frutos danificados, 2 e 3 semanas após a captura. Assim, foram obtidas equações que relacionam a captura e o dano, possibilitando estimar níveis de controle desse inseto. As perdas médias causadas por C. capitata em laranja cv. Hamlin chegaram a 2,5 toneladas de frutos por hectare ou 7,5% da produção.info:eu-repo/semantics/publishedVersio

    Comparative study of the atmospheric chemical composition of three South American cities

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    PM10 samples were collected in 2008 at three sites in South America in the framework of an international project (South American Emissions Megacities, and Climate; SAEMC). The concentration of metals, metalloids, ion and organic compounds of most PM10 samples collected at three sites (Buenos Aires (BAI), Bogotá (BOG) and São Paulo (SPA)) is below the air quality standard of the respective countries. At the sites n-alkanes and carbon preference index distribution indicated the influence of petroleum residues derived from vehicular emissions. Most PAH detected are attributed to light-duty gasoline vehicles and to stationary sources. At all sites benzo[a]pyrene equivalent values mean a significant cancer risk. Sulfate, nitrate, ammonium, calcium and sodium are the most abundant water-soluble ions at the three sites. Ammonium sulfate is likely the form presented for these species formed by photochemical reactions of precursors emitted mainly by vehicles. At BAI and SPA, formate/acetate ratios indicated the contribution of photochemical reactions; on the contrary, at BOG site, acetate is predominant, indicating strong contribution of vehicular emissions. São Paulo samples showed the highest concentrations of elements among all the sites. None of the toxic or potentially toxic elements exceed the guideline values of the World Health Organization. At BAI site earth crust seems to be the major source of Fe and Mn; at SPA, anthropogenic source is responsible for Pb and Zn presences. Traffic related element is well correlated at the three sites.Fil: Vasconcellos, Pérola C.. Universidade de Sao Paulo; BrasilFil: Souza, Davi Z.. Instituto Nacional de Pesquisas Nucleares; BrasilFil: Ávila, Simone G.. Universidade de Sao Paulo; BrasilFil: Araújo, Maria P.. Universidade de Sao Paulo; BrasilFil: Naoto, Edson. Universidade de Sao Paulo; BrasilFil: Nascimento, Kátia H.. Universidade de Sao Paulo; BrasilFil: Cavalcante, Fernando S.. Universidade de Sao Paulo; BrasilFil: Dos Santos, Marina. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Smichowski, Patricia Nora. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Behrentz, Eduardo. Universidad de los Andes; Colombi

    Vascular retinal findings after COVID-19 vaccination in 11 cases: a coincidence or consequence?

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    Purpose: The primary purpose of this study was to assess vascular retinal findings temporally related to COVID-19 vaccination. With greater information regarding all possible future adverse events, we hope to understand the real dimension and relevance of what was presented. Methods: Eleven patients with visual complaints after COVID-19 vaccination were enrolled. Data on the following were included: age, sex, vaccine, time of symptom onset, systemic findings, medical history, best-corrected visual acuity, and ocular findings by slit-lamp biomicroscopy as well as multimodal retinal imaging (color fundus, red-free photography, spectral-domain optical coherence tomography, optical coherence tomography angiography, and fluorescein-angiography). Inclusion criteria were the presence of ophthalmologic signs within 30 days after the first or second dose of any COVID-19 vaccine. Results: Of 11 patients, five had arterial occlusion (45.4%), four had venous occlusion (36.4%), and two (18.2%) had nonspecific vascular alterations suggestive of retinal ischemia such as cotton-wool spots. The mean age was 57 (SD = 16; range: 27-84) years. The mean time of symptoms onset was 10 (SD = 5.4; range: 3-16) days. Nine patients were female (81.8%). Systemic risk factors were observed in 36.4% of patients. Two patients had both neurological and visual symptoms, with arterial occlusion. Overall, 36.4% patients had COVID-19 in the previous year. Seven patients (63.6%) received ChAdOx1 nCoV- 19 (AZD1222) vaccine. Conclusions: Our data suggest that retinal events temporally related to COVID-19 vaccination are possible but are very rare. The relationship of these events with post-COVID-19 vaccination warrants further attention to derive a meaningful conclusion.RESUMO Objetivos: o principal objetivo deste estudo foi descrever pacientes com achados vasculares retinianos temporalmente relacionados à vacinação contra COVID-19. Com maior notificação de possíveis eventos adversos similares, esperamos compreender a real dimensão e relevância do que foi apresentado. Métodos: Onze pacientes com queixas visuais após vacinação contra COVID-19 foram estudados. Os dados analisados foram: idade, gênero, tipo de vacinação, tempo de aparecimento de sintomas, achados sistêmicos, antecedentes pessoais, acuidade visual com melhor correção, biomicroscopia e imagem retiniana multimodal (retinografia colorida, red-free, SD-OCT, OCTA e angiofluoresceinografia). Os critérios de inclusão foram a presença de alterações oftalmológicas ocorridas dentro de 30 dias após a primeira ou segunda dose de qualquer vacina contra COVID-19. Resultados: Onze pacientes foram incluídos: 5 com oclusão arterial (45,4%), 4 com oclusão venosa (36,4%) e 2 (18,2%) com alterações não específicas vasculares sugestivas de isquemia retiniana como exsudatos algodonosos. A idade média dos pacientes foi de 57 anos (DP=16; com intervalo de 27 a 84 anos). A média de tempo de aparecimento de sintomas após a vacinação foi de 10 dias (DP=5,4; com intervalo de 3 a 16 dias). Nove dos onze pacientes eram do sexo feminino (81,8%). Fatores de risco sistêmicos foram observados em 36,4% dos pacientes. Dois pacientes tiveram sintomas neurológicos e visuais, com oclusão arterial. 36,4% dos pacientes tiveram infecção prévia por COVID-19 no último ano. Sete pacientes (63,6%) receberam a vacina ChAdOx1 nCoV-19 (AZD1222). Conclusões: nossos dados sugerem que eventos retinianos temporalmente relacionados à vacinação contra COVID-19 são possíveis, porém raros. A relação entre estes eventos pós-vacinais exigem futura atenção antes de maiores conclusões

    ATIVIDADE LEISHMANICIDA in vitro DE FRAÇÕES DO EXTRATO HIDROALCOÓLICO DAS FOLHAS DE Chenopodium ambrosioides L.

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    A leishmaniose é uma doença infecciosa causada por protozoários do gênero Leishmania e representa sério problema de saúde pública em paises da África, Ásia e América Latina. Chenopodium ambrosioides L.,  popularmente conhecido como mastruz, tem sido utilizado no Maranhão para o tratamento tópico de úlceras leishmanióticas. O trabalho avaliou a eficácia das frações do extrato hidroalcoólico das folhas de C. ambrosioides contra formas promastigotas da espécie Leishmania amazonensis. O fracionamento foi realizado pela partição sequencial do extrato hidroalcoólico de folhas de C. ambrosioides com solventes de polaridade crescente (hexano, clorofórmio e acetato de etila). As formas promastigotas foram cultivadas em meio RPMI 1640 com e sem as frações. Após 24h de incubação a 26ºC, o número de promastigotas viáveis foi contado pelo método direto em câmara de Neubauer. As concentrações que inibem o crescimento de 50% (CI50 ) das promastigotas de L. amazonensis foram calculadas a partir da avaliação da mortalidade das promastigotas in vitro. De acordo com escores padrões nas frações de acetato de etila e hidroalcoólica remanescente não foi observada atividade leishmanicida significativa, mas as frações hexânica e clorofórmica apresentaram-se ativas. Os resultados obtidos demonstram uma ação leishmanicida promissora das frações. Estudos futuros são necessários para investigar a eficácia destas frações no tratamento da leishmaniose em modelos experimentais in vivo.Descritores: Chenopodium ambrosioides L.; Mastruz; Leishmaniose; in vitro. Abstract:  In vitro leishmanicidal activity of fractions obtained from hydroalcoholic extracts of  Chenopodium ambrosioides’  leaves. Leishmaniasis is an infectious disease caused by protozoa of the genus Leishmania and represents serious public health problem in Africa, Asia and Latin America. Chenopodium ambrosioides, popularly known as “mastruz”, has been used in Maranhão for the topical treatment of leishmanial ulcers. The study evaluated the effectiveness of the fractions from hydroalcoholic extract of C. ambrosioides’  leaves against the promastigotes of Leishmania amazonensis. Fractionation as accomplished by partition sequential extract of leaves of C. ambrosioides with solvents of increasing polarity (hexane, chloroform and ethyl acetate). The promastigotes forms were cultured in supplemented RPMI 1640 with or without fractions. After 24h incubation at 26°C, the number of viable promastigotes was counted by the direct method in a Neubauer chamber. The concentrations that inhibit growth of 50% (IC50 ) of L. amazonensis’ promastigotes were calculated from the assessment of the mortality of promastigotes in vitro. According to standard scores, in the ethyl acetate and hydroalcoholic remaining fractions there was no leishmanicidal activity, while the hexane and chloroform fractions were actives. The results showed a promissor leishmanicidal activity of fraction. Future studies are necessary to investigate the effectiveness of these fractions in the treatment of these fractions in experimental models in vivo.Descriptors: Chenopodium ambrosioides L.; Mastruz; Leishmaniasis; in vitro

    T-Cell Memory Responses Elicited by Yellow Fever Vaccine are Targeted to Overlapping Epitopes Containing Multiple HLA-I and -II Binding Motifs

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    The yellow fever vaccines (YF-17D-204 and 17DD) are considered to be among the safest vaccines and the presence of neutralizing antibodies is correlated with protection, although other immune effector mechanisms are known to be involved. T-cell responses are known to play an important role modulating antibody production and the killing of infected cells. However, little is known about the repertoire of T-cell responses elicited by the YF-17DD vaccine in humans. In this report, a library of 653 partially overlapping 15-mer peptides covering the envelope (Env) and nonstructural (NS) proteins 1 to 5 of the vaccine was utilized to perform a comprehensive analysis of the virus-specific CD4+ and CD8+ T-cell responses. The T-cell responses were screened ex-vivo by IFN-γ ELISPOT assays using blood samples from 220 YF-17DD vaccinees collected two months to four years after immunization. Each peptide was tested in 75 to 208 separate individuals of the cohort. The screening identified sixteen immunodominant antigens that elicited activation of circulating memory T-cells in 10% to 33% of the individuals. Biochemical in-vitro binding assays and immunogenetic and immunogenicity studies indicated that each of the sixteen immunogenic 15-mer peptides contained two or more partially overlapping epitopes that could bind with high affinity to molecules of different HLAs. The prevalence of the immunogenicity of a peptide in the cohort was correlated with the diversity of HLA-II alleles that they could bind. These findings suggest that overlapping of HLA binding motifs within a peptide enhances its T-cell immunogenicity and the prevalence of the response in the population. In summary, the results suggests that in addition to factors of the innate immunity, "promiscuous" T-cell antigens might contribute to the high efficacy of the yellow fever vaccines. © 2013 de Melo et al

    Revisiting the term neuroprotection in chronic and degenerative diseases

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    Thanks to the development of several new researches, the lifetime presented a significant increase, even so, we still have many obstacles to overcome - among them, manage and get responses regarding neurodegenerative diseases. Where we are in the understanding of neuroprotection? Do we really have protective therapies for diseases considered degeneratives such as amyotrophic lateral sclerosis and its variants, Parkinson's disease, Alzheimer's disease and many others? Neuroprotection is defined by many researches as interactions and interventions that can slow down or even inhibit the progression of neuronal degeneration process. We make some considerations on this neuroprotective effect.Department of Neurology, Antonio Pedro University Hospital, Fluminense Federal University , NiteróiNeurology Service, Nova Iguaçu Hospital , PosseBrain Mapping Laboratory and Electroencephalogram, Federal University of Rio de JaneiroBrain Mapping and Functionality Laboratory, Federal University of PiauíSeverino Sombra University Center, School of Medicine , VassourasDepartment of Neurology, Federal University of São Paulo , BrazilDepartment of Neurology, Federal University of São Paulo , BrazilWeb of Scienc

    A proposal for the evaluation of the bioeconomic efficiency of beef cattle production systems

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    ABSTRACT The objective of this study was to identify types of production system and their main indicators on bioeconomic efficiency, using qualitative and quantitative methods to evaluate beef cattle farms in the western region of the state of Rio Grande do Sul. A survey was carried out with 43 farmers operating in the western region of that state. All farms operated with complete cycle production systems in areas larger or equal to 900 ha. A qualitative questionnaire with binary answers and a quantitative questionnaire with numerical answers were applied. Technology and Management drivers were used for the calculation of the efficiency index of farmers obtained by both questionnaires. Farmers were divided into three clusters: low-efficiency level (LEL), intermediate-efficiency level (IEM), or high-efficiency level (HEL), as a result of the comparison of the scores obtained for the analyzed parameters. Subfactors resulting from each comparison (LEL × IEL; LEL × HEL, and IEL × HEL) were different as a function of the comparison and of the methods applied. Low-efficiency level farmers need to improve essential production processes, such as technology and management, as well as health management practices together with the financial management of the production system. Intermediate-efficiency level farmers need to improve their routine animal management, pasture management, and calculation of financial indicators to become highly efficient. The quantitative method allowed to identify underestimation (39.3%) or overestimation (24.2%) when farmers were are classified in clusters. Different methods may be used, but those based on quantitative information have stronger discrimination power to identify different types of farmers
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