39 research outputs found

    Specific heat and magnetization study on single crystals of a frustrated, quasi one-dimensional oxide: Ca3Co2O6

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    Specific heat and magnetization measurements have been carried out under a range of magnetic fields on single crystals of Ca3Co2O6. This compound is composed of Ising magnetic chains that are arranged on a triangular lattice. The intrachain and interchain couplings are ferromagnetic and antiferromagnetic, respectively. This situation gives rise to geometrical frustration, that bears some similarity to the classical problem of a two-dimensional Ising triangular antiferromagnet. This paper reports on the ordering process at low-T and the possibility of one-dimensional features at high-T.Comment: 7 pages, 6 figures, accepted for publication in PR

    Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

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    Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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    Estabilidade de farinha de batata-doce biofortificada Stability of biofortified sweet potato flour

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    A farinha de batata-doce, quando elaborada a partir de raízes com alto teor de &#946;-caroteno, é fonte de pró-vitamina A, que apresenta efeitos benéficos na saúde humana. Visando contribuir com o suprimento de vitamina A na alimentação de populações carentes, a EMBRAPA tem selecionado e melhorado culturas via biofortificação, como da batata-doce, e pesquisado o desenvolvimento de produtos com esta matéria-prima biofortificada. Complementando esses desenvolvimentos, o objetivo deste estudo foi comparar o efeito do tipo de embalagem e do sistema de acondicionamento do produto na preservação de carotenoides de farinha de batata-doce biofortificada. A farinha foi acondicionada com e sem vácuo, em embalagens com diferentes barreiras ao oxigênio, vapor d'água e luz (PET/Al/PEBD, PETmet/PEBD, PEBD/PA/PEBD e PEBD) e estocada a 25 °C/75%UR com e sem exposição à luz por um ano. Perdas de 50% de carotenoides totais e &#946;-caroteno ocorreram na farinha em PETmet/PEBD e PEBD sem vácuo, aos 50 dias de estocagem, em razão do teor de oxigênio residual presente no espaço livre e também da alta permeação de oxigênio pelo material no caso do PEBD, no qual a composição do ar foi mantida durante todo o estudo. Perdas de 50% de carotenoides ocorreram aos 90 dias com ou sem exposição à luz no produto em PEBD/PA/PEBD com vácuo, indicando que a reação de oxidação de carotenoides sob luz se restringe apenas à farinha em contato com a superfície da embalagem. Sob vácuo e em PETmet/PEBD, os teores de carotenoides na farinha diminuíram ligeiramente e foram mantidos no PET/Al/PEBD, até 360 dias de estocagem. Os resultados indicaram que a redução do teor de oxigênio no espaço livre da embalagem por meio da aplicação de vácuo aliada ao uso de materiais de embalagem com barreira ao oxigênio da ordem de grandeza de PET com metalização barreira são os fatores mais importantes na preservação de carotenoides em farinha de batata-doce biofortificada.<br>Sweet potato flour, when made from roots with high &#946;-carotene contents, is a source of pro-vitamin A, presenting beneficial effects for human health. Thus aiming at contributing to the supply of vitamin A in the diet of more needy populations, EMBRAPA has selected and improved some crops via biofortification, such as the sweet potato, and developed products with the biofortified raw material. Complementing these developments, the purpose of this study was to correlate the effect of the type of package and packaging system on the product, in the preservation of the carotenoids in the biofortified sweet potato flour. The flour was packed with and without vacuum in packs with different oxygen, water vapour and light barriers (PET/Al/LDPE, PETmet/LDPE, LDPE/PA/LDPE and LDPE) and stored at 25 °C/75%RH with and without exposure to light. Losses of 50% of the total carotenoids and &#946;-carotene occurred in the flour packed in PETmet/LDPE and LDPE without vacuum after 50 days of storage, due to the residual oxygen in the headspace and the high oxygen transmission rate in the case of LDPE, where the internal atmosphere showed the composition of air throughout the study. Losses of 50% carotenoids occurred after 90 days with and without exposure to light in the flour packed in LDPE/PA/LDPE with vacuum, indicating that in the presence of light, the carotenoid oxidation reaction is restricted to flour in contact with the surface of the package. Under vacuum and packed in PETmet/LDPE, the carotenoid contents of the flour reduced slightly, but were preserved for up to 360 days of storage when packed in PET/Al/LDPE. The results indicate that the key factors to preserve carotenoids in biofortified sweet potato flour are the reduction of the oxygen level in the headspace of the package by the application of vacuum, together with the use of packaging materials with an oxygen barrier as good as that of PET with a metalized barrier

    Probiotic yogurts manufactured with increased glucose oxidase levels: postacidification, proteolytic patterns, survival of probiotic microorganisms, production of organic acid and aroma compounds

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    We investigated the effect of increased glucose oxidase concentration as a technological option to decrease oxidative stress during the processing of probiotic yogurts. Probiotic yogurts were produced with increased concentrations of glucose oxidase (0, 250, 500, 750, or 1,000 mg/kg) and submitted to physicochemical and microbiological analysis at 1, 15, and 30 d of refrigerated storage. Higher concentrations of glucose oxidase (750 and 1,000 mg/kg) and a longer storage time were found to have an influence on the characteristics of the probiotic yogurt, contributing to more extensive postacidification, an increase in the dissolved oxygen level, and higher proteolysis. In addition, increased production of aroma compounds (diacetyl and acetaldehyde) and organic acids (mainly lactic acid) and a decrease in the probiotic bacteria count were reported. The use of glucose oxidase was a feasible option to minimize oxidative stress in probiotic yogurts. However, supplementation with excessive amounts of the enzyme may be ineffective, because insufficient substrate (glucose) is present for its action. Consumer tests should be performed to evaluate changes in the sensory attributes of the probiotic yogurts with increased supplementation of glucose oxidase. In addition, packaging systems with different permeability to oxygen should be evaluated9552261226

    Probiotic Yogurts Manufactured With Increased Glucose Oxidase Levels: Postacidification, Proteolytic Patterns, Survival Of Probiotic Microorganisms, Production Of Organic Acid And Aroma Compounds.

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    We investigated the effect of increased glucose oxidase concentration as a technological option to decrease oxidative stress during the processing of probiotic yogurts. Probiotic yogurts were produced with increased concentrations of glucose oxidase (0, 250, 500, 750, or 1,000 mg/kg) and submitted to physicochemical and microbiological analysis at 1, 15, and 30 d of refrigerated storage. Higher concentrations of glucose oxidase (750 and 1,000 mg/kg) and a longer storage time were found to have an influence on the characteristics of the probiotic yogurt, contributing to more extensive postacidification, an increase in the dissolved oxygen level, and higher proteolysis. In addition, increased production of aroma compounds (diacetyl and acetaldehyde) and organic acids (mainly lactic acid) and a decrease in the probiotic bacteria count were reported. The use of glucose oxidase was a feasible option to minimize oxidative stress in probiotic yogurts. However, supplementation with excessive amounts of the enzyme may be ineffective, because insufficient substrate (glucose) is present for its action. Consumer tests should be performed to evaluate changes in the sensory attributes of the probiotic yogurts with increased supplementation of glucose oxidase. In addition, packaging systems with different permeability to oxygen should be evaluated.952261-
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