188 research outputs found
OS FENOIS VOLATEIS E OS SEUS PRECURSORES EM SOLUÇÕES MODELO E EM VINHO
A produção de fenóis voláteis tem causado grande preocupação na indústria vitivinícola por ser responsável pela introdução de aromas desagradáveis que afectam a qualidade dos vinhos. Os etilfenóis, resultantes da degradação dos ácidos hidroxicinâmicos devido à actividade microbiana, conferem aos vinhos um aroma a estrebaria quando presentes em concentrações elevadas.
Este trabalho teve como principal objectivo avaliar a influência das leveduras do género Brettanomyces/Dekkera na degradação dos ácidos hidroxicinâmicos, tentando correlacioná-la com a taxa de formação dos etilfenóis.
A composição de ácidos fenólicos e de fenóis voláteis num meio sintético e em vinhos tintos inoculados com leveduras deste género foi determinada por HPLC-DAD e GC-FID, respectivamente. Através destes métodos analíticos foi possível identificar e quantificar os ácidos cafeico, cumárico e ferúlico e os etilfenóis 4-etilcatecol, 4-etilfenol e 4-etilguaiacol ao longo do tempo. Os resultados obtidos permitiram concluir que as leveduras D. bruxellensis podem ser consideradas leveduras contaminantes muito importantes, dada a sua capacidade de produzirem quantidades elevadas de etilfenóis que são responsáveis pela deterioração do vinho
Assessment of Dimethoate in Olive Oil Samples Using a Dual Responsive Molecularly Imprinting-Based Approach
A new generation of advanced materials developed by molecular imprinting technology
showing a stimuli-responsive functionality are emerging. The switchable ability to control
the uptake/release of the target analyte by action of external stimulus combined with a
remarkable selectivity and specificity, makes these functional materials very attractive for sample
preparation purposes. In this work, the usefulness of a sample preparation tool for the selective
enrichment/pre-concentration of dimethoate from olive oil spiked samples based on “tailor-made”
dual responsive magnetic and photonic molecularly imprinted polymers as sorbents is explored.
To achieve this goal, a smart molecularly imprinted polymer (MIP) possessing magnetic and
photonic responsiveness was successfully synthesized, and its physico-chemical and morphological
characterization was assessed. Further, the trace analysis of dimethoate in spiked olive oil samples
was validated and successfully implemented using smart-MIPs as sorbents in the sample preparation
step, with high recoveries (83.5 0.3%) and low detection limit (0.03 g mL 1)
Production of Medium-Chain Length Polyhydroxyalkanoates by Pseudomonas citronellolis Grown in Apple Pulp Waste
Background and objective: Apple pulp waste generated by the fruit processing industry is a sugar-rich material with great potential to be used as a feedstock for production of value added microbial products. The aim of this work was to use this feedstock for the cultivation of Pseudomonas citronellolis and production of medium-chain-length polyhydroxyalkanoates, a natural elastomer.Material and methods: The solid fraction of the apple pulp waste was discarded and the soluble fraction, rich in fructose (17.7 g l-1), glucose (7.5 g l-1) and sucrose (1.2 g l-1), was used for the batch bioreactor cultivation of Pseudomonas citronellolis NRRL B-2504.Results and conclusion: Pseudomonas citronellolis reached a polymer content in the biomass of 30% wt and a volumetric productivity of 0.025 g l-1 h-1. The polymer was mainly composed of 3-hydroxydecanoate (68% mol) and 3-hydroxyoctanoate (22% mol), with minor contents of 3-hydroxydodecanoate (5% mol), 3-hydroxytetradecanoate (4% mol) and 3-hydroxyhexanoate (1% mol), and had a molecular weight of 3.7×105 Da. It presented glass transition and melting temperatures of -12 and 53°C, respectively, and a thermal degradation temperature of 296°C. The polymer’s films were dense, ductile and permeable to oxygen and carbon dioxide. These results demonstrated that apple pulp waste is a suitable feedstock for the production of a biopolymer with properties that render it a promising alternative to some synthetic petrochemical-derived polyesters.Conflict of interest: The authors declare no conflict of interest
Lipodystrophy defined by Fat Mass Ratio in HIV-infected patients is associated with a high prevalence of glucose disturbances and insulin resistance
INTRODUCTION: Combined antiretroviral therapy (cART) in the treatment of HIV-1 infection has been associated with complications, including lipodystrophy, hyperlipidaemia, insulin resistance (IR) and diabetes. AIMS: To compare the prevalence of glucose homeostasis disturbances and IR in HIV patients on cART according to the presence of lipodystrophy (defined clinically and by Fat Mass Ratio) and different patterns of fat distribution and to establish their associations. DESIGN: Cross-sectional cohort study. METHODS: We evaluated body composition and IR and insulin sensitivity indexes in 345 HIV-infected adults. RESULTS: Patients with clinical lipodystrophy (CL) had higher plasma glucose levels than patients without CL, without significant differences in plasma insulin levels, A1c, HOMA-IR, HOMA-B, QUICKI, or MATSUDA index. Patients with lipodystrophy defined by FMR had higher plasma glucose and insulin levels, A1c, HOMA-IR, QUICKI and MATSUDA than patients without lipodystrophy, without differences in HOMA-B. Higher insulin resistance (HOMA-IR ≥ 4) was present in patients with FMR-defined lipodystrophy. Patients with FMR-defined lipodystrophy had a higher prevalence of IFG, IGT and DM than patients without lipodystrophy. Significant associations between HOMA-IR and total, central and central/peripheral fat evaluated by CT at abdominal level were found and no association between HOMA-IR and peripheral fat. Association between HOMA-IR and total and trunk fat but no association with leg and arm fat (evaluated by DXA) was found. CONCLUSIONS: IR and glucose disturbances were significantly increased in patients with FMR-defined lipodystrophy. FMR lipodystrophy definition seems to be a more sensitive determinant of insulin resistance and glucose disturbances than clinical definition
Surto de sarampo na regiao metropolitana de Campinas, SP
O Brasil não apresenta circulação endêmica do vírus do sarampo desde o ano 2000. Entre maio e junho de 2011, a Região Metropolitana de Campinas, Estado de São Paulo, registrou três casos de sarampo. Foram descritos casos, as medidas de controle, a busca de possível fonte e de casos secundários. A caracterização genotípica do vírus identificou o genótipo D4, circulante no continente europeu. Não foram encontrados casos índice ou secundários. As medidas de controle efetuadas, aliadas à cobertura vacinal adequada da Região Metropolitana de Campinas contribuíram para que a transmissão da doença fosse interrompida
Genetic Diversity Strategy For The Management And Use Of Rubber Genetic Resources: More Than 1,000 Wild And Cultivated Accessions In A 100-genotype Core Collection
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. Arg.] is the only plant species worldwide that is cultivated for the commercial production of natural rubber. This study describes the genetic diversity of the Hevea spp. complex that is available in the main ex situ collections of South America, including Amazonian populations that have never been previously described. Genetic data were analyzed to determine the genetic structure of the wild populations, quantify the allelic diversity and suggest the composition of a core collection to capture the maximum genetic diversity within a minimal sample size. A total of 1,117 accessions were genotyped with 13 microsatellite markers. We identified a total of 408 alleles, 319 of which were shared between groups and 89 that were private in different groups of accessions. In a population structure and principal component analysis, the level of clustering reflected a primary division into the following two subgroups: cluster 1, which consisted of varieties from the advanced breeding germplasm that originated from the Wickham and Mato Grosso accessions; and cluster 2, which consisted of the wild germplasm from the Acre, Amazonas, Para and Rondonia populations and Hevea spp. The analyses revealed a high frequency of gene flow between the groups, with the genetic differentiation coefficient (GST) estimated to be 0.018. Additionally, no distinct separation among the H. brasiliensis accessions and the other species from Amazonas was observed. A core collection of 99 accessions was identified that captured the maximum genetic diversity. Rubber tree breeders can effectively utilize this core collection for cultivar improvement. Furthermore, such a core collection could provide resources for forming an association panel to evaluate traits with agronomic and commercial importance. Our study generated a molecular database that should facilitate the management of the Hevea germplasm and its use for subsequent genetic and genomic breeding.107Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FAPESP [2007/50392-1, 2012/50491-8, 2011/50188-0, 2009/52975-0, 2012/05473-1]CNPq [478701/2012-8, 402954/2012-2
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