611 research outputs found

    Pt-Decorated TiO2 Materials Supported on Carbon : Increasing Activities and Stabilities toward the ORR by Tuning the Pt Loading

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    Pt nanoparticles (Pt NPs) supported on carbon have been widely employed as electrocatalysts toward oxygen reduction reaction. The development of more efficient electrocatalysts that enable one to reduce or even not require the use of Pt is a central challenge. In addition to the control over the physical and chemical features of Pt NPs, metal support interactions can be employed to enhance activities via the generation and exposure of surface-active sites. In this context, we report herein the development of electrocatalysts composed of Pt NPs supported on TiO2 microspheres, that were subsequently impregnated onto carbon. We have found that, by optimizing the loading of Pt at the TiO2 surface, the electrocatalytic activity toward the ORR could be improved compared to that of the commercial Pt/C (E-TEK) material, even at lower Pt loadings. The enhancement in activities could be assigned to the balance between Pt loading and generation of reactive surface sites, such as adsorbed oxygenated species. Moreover, the utilization of TiO2 as support enabled improved stabilities relative to Pt/C (E-TEK). We believe that the results described herein may inspire the development of electrocatalysts for the ORR with improved activities and stabilities.Peer reviewe

    Age effects on EEG correlates of the Wisconsin card sorting test

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    Body and brain undergo several changes with aging. One of the domains in which these changes are more remarkable relates with cognitive performance. In the present work, electroencephalogram (EEG) markers (power spectral density and spectral coherence) of age-related cognitive decline were sought whilst the subjects performed the Wisconsin Card Sorting Test (WCST). Considering the expected age-related cognitive deficits, WCST was applied to young, mid-age and elderly participants, and the theta and alpha frequency bands were analyzed. From the results herein presented, higher theta and alpha power were found to be associated with a good performance in the WCST of younger subjects. Additionally, higher theta and alpha coherence were also associated with good performance and were shown to decline with age and a decrease in alpha peak frequency seems to be associated with aging. Additionally, inter-hemispheric long-range coherences and parietal theta power were identified as age-independent EEG correlates of cognitive performance. In summary, these data reveals age-dependent as well as age-independent EEG correlates of cognitive performance that contribute to the understanding of brain aging and related cognitive deficits.The work was partially funded by the European Commission (FP7): “SwitchBox” (Contract HEALTH‐F2‐2010‐259772) and co‐financed by the Portuguese North Regional Operational Program (ON.2 – O Novo Norte) under the National Strategic Reference Framework (QREN), through the European Regional Development Fund (FEDER). This work was also co‐sponsored by FCT – Foundation for Science and Technology and Compete Program with the project reference FCOMP‐01‐0124‐FEDER‐021145 (PTDC/SAU‐ENB/118383/2010) and Agência De Inovação “DoIT ‐ Desenvolvimento e Operacionalização da Investigação de Translação” (project no. 13853, PPS4‐MyHealth), funded by Fundo Europeu de Desenvolvimento Regional (FEDER) through the Programa Operacional Factores de Competitividade (POFC)

    A localized outbreak of Chikungunya virus in Salvador, Bahia, Brazil

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    A localized Chikungunya virus (CHIKV; East/Central/South African genotype) outbreak (50 cases, 70% laboratory-confirmed; attack rate: 5.3 confirmed cases/100 people) occurred in a Salvador, Brazil neighborhood, between Apr-Jun/2017. Highly clustered cases in space and time, mostly along a single street, highlight an increased risk of CHIKV transmission among pockets of susceptible populations. This finding underscores the need for ongoing local level surveillance for arboviral outbreaks.Fil: Tauro, Laura Beatriz. Fundación Oswaldo Cruz; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; ArgentinaFil: Cardoso, Cristiane W.. Secretaria Municipal da Saúde de Salvador; BrasilFil: Souza, Raquel L.. Fundación Oswaldo Cruz; BrasilFil: Nascimento, Leile Cj. Fundación Oswaldo Cruz; BrasilFil: Santos, Daniela R Dos. Secretaria Municipal da Saúde de Salvador; BrasilFil: Campos, Gubio S.. Universidade Federal da Bahia; BrasilFil: Ferro Sardi, Silvia Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidade Federal da Bahia; BrasilFil: Reis, Olivete B Dos. Secretaria Municipal da Saúde de Salvador; BrasilFil: Reis, Mitermayer G.. Fundación Oswaldo Cruz; Brasil. Universidade Federal da Bahia; Brasil. University of Yale; Estados UnidosFil: Kitron, Uriel D.. Fundación Oswaldo Cruz; Brasil. University of Emory; Estados UnidosFil: Ribeiro, Guilherme S.. Universidade Federal da Bahia; Brasil. Fundación Oswaldo Cruz; Brasi

    Disruption of the inositol phosphorylceramide synthase gene affects Trypanosoma cruzi differentiation and infection capacity

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    Sphingolipids (SLs) are essential components of all eukaryotic cellular membranes. In fungi, plants and many protozoa, the primary SL is inositol-phosphorylceramide (IPC). Trypanosoma cruzi is a protozoan parasite that causes Chagas disease (CD), a chronic illness for which no vaccines or effective treatments are available. IPC synthase (IPCS) has been considered an ideal target enzyme for drug development because phosphoinositol-containing SL is absent in mammalian cells and the enzyme activity has been described in all parasite forms of T. cruzi. Furthermore, IPCS is an integral membrane protein conserved amongst other kinetoplastids, including Leishmania major, for which specific inhibitors have been identified. Using a CRISPR-Cas9 protocol, we generated T. cruzi knockout (KO) mutants in which both alleles of the IPCS gene were disrupted. We demonstrated that the lack of IPCS activity does not affect epimastigote proliferation or its susceptibility to compounds that have been identified as inhibitors of the L. major IPCS. However, disruption of the T. cruzi IPCS gene negatively affected epimastigote differentiation into metacyclic trypomastigotes as well as proliferation of intracellular amastigotes and differentiation of amastigotes into tissue culture-derived trypomastigotes. In accordance with previous studies suggesting that IPC is a membrane component essential for parasite survival in the mammalian host, we showed that T. cruzi IPCS null mutants are unable to establish an infection in vivo, even in immune deficient mice

    The influence of regular physical activity on the self-concept

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    Foi objetivo desta pesquisa estudar a influência da atividade física regular de homens e mulheres de mais de 40 anos sobre o seu autoconceito. A Escala Fatorial de Autoconceito foi administrada a 200 sujeitos, metade deles praticando algum tipo de atividade física regular no momento da pesquisa e a outra metade sendo sedentários. A Anova 2X2 revelou efeito principal da atividade física regular e do gênero sobre vários fatores do autoconceito. Os escores foram superiores em autoconfiança, autocontrole e self somático para o grupo experimental e no self ético-moral para as mulheres. Conclui-se que a atividade física regular tem impacto benéfico sobre o autoconceito.The objective of this research was to study the effect of regular physical activity of men and women over 40 on their self-concept. The Self-concept Factorial Scale was administered to 200 subjects, half of them practicing some kind of regular physical activity and the other half being sedentary. The Anova 2X2 revealed a main effect of physical activity and gender on several factors of the self-concept. The scores were higher for the experimental group on self-confidence, self-control, and somatic self. Men scored higher on self-confidence while women on moral self. It was concluded that regular physical activity is beneficial for self-concept

    Rhodium catalyzed hydroformylation of kaurane derivatives: A route to new diterpenes with potential bioactivity

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    Kaurenic and grandiflorenic acids are naturally occurring diterpenes whose biological activity has been described. Both acids contain an exocyclic methylenic double bond that allows further functionalization on their structure. In an attempt to expand the number of derivatives of these two natural products, we have undertaken a study on the hydroformylation of the methyl esters of the two acids and the trimethylsilyl ether of kaurenol. These substrates have been hydroformylated by using unmodified Rh catalysts, as well as Rh/PPh3 and Rh/tris-(o-t-butylphenyl)phosphite catalytic systems at 100 °C and 20 bar of CO/H2 (1:1). For the three substrates, the two Rh catalysts modified with P-donor ligands, produced high conversions and chemo- and regioselectivities in the diastereoisomeric pair of linear aldehydes. In all cases, the stereoselectivity observed is strongly dependent of the system used, being the most diastereoselective the least hindered unmodified Rh/CO catalyst. A correlation between the higher diastereoselectivity and the faster [beta]-elimination of the metal-alkyl intermediate observed in the unmodified system is discussed.http://www.sciencedirect.com/science/article/B6TF5-4RVMXFD-3/1/d27e671ad9e0b7fc325dfd0bdf413c7

    Cuidados na gestação, pós-parto e com bebês pelas mulheres do povoado de Pedra Branca, Santa Terezinha, Bahia

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    This present article records how women who live in a village from the interior of Bahia State, northeastern Brazil, perceive and deal with the care they are supposed to receive during their pregnancy, in the post-delivery period, and with new-born babies. Fieldwork was carried out by students in the Ethnobiology program of Universidade Estadual de Feira de Santana. They performed open-ended interviews with seven female inhabitants of the village of Pedra Branca in May 2004. The interviewees’ ages ranged from 18 to 60 years. Local obstetric knowledge and practices, as well as those concerning the care for babies were contrasted with information from the academic literature. It was observed that, although traditional practices have been transmitted from generation to generation, younger women of this community do not give the same importance to these folk knowledge as the more experienced women do.O presente artigo registra como as mulheres que vivem em um povoado do interior do estado da Bahia, nordeste do Brasil, percebem e lidam com os cuidados que devem ter durante a gravidez, no período pós-parto e com os recém-nascidos. O trabalho de campo foi conduzido por alunos da disciplina Etnobiologia da Universidade Estadual de Feira de Santana, que realizaram entrevistas semi-estruturadas com sete moradoras do povoado de Pedra Branca, em maio de 2004. As mulheres entrevistadas tinham idades entre 18 e 60 anos. Os conhecimentos e práticas obstétricas locais e com relação aos cuidados com os bebês foram contrastados com informações da literatura acadêmica pertinente. Foi observado que as mulheres mais jovens da comunidade cada vez mais dão menos importância às práticas tradicionais transmitidas pelas mulheres mais experientes

    Leishmanicidal and Immunomodulatory Activities of the Palladacycle Complex DPPE 1.1, a Potential Candidate for Treatment of Cutaneous Leishmaniasis

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    The present study focused on the activity of the palladacycle complex DPPE 1.1 on Leishmania (Leishmania) amazonensis. Promastigotes of L. (L.) amazonensis were destroyed in vitro by nanomolar concentrations of DPPE 1.1, whereas intracellular amastigotes were killed at drug concentrations fivefold less toxic than those harmful to macrophages. L. (L.) amazonensis-infected BALB/c mice were treated by intralesional injection of DPPE 1.1. Animals treated with 3.5 and 7.0 mg/kg of DPPE 1.1 showed a significant decrease of foot lesion sizes and a parasite load reduction of 93 and 99%, respectively, when compared to untreated controls. Furthermore, DPPE 1.1 was non-toxic to treated animals. The cathepsin B activity of L. (L.) amazonensis amastigotes was inhibited by DPPE 1.1 as demonstrated spectrofluorometrically by use of a specific fluorogenic substrate. Analysis of T-cells populations in mice treated with DPPE 1.1 and untreated controls was performed by fluorescence-activated cell sorter (FACS). IFN-γ was measured in supernatants of lymphocytes from popliteal and inguinal lymph nodes isolated from treated and untreated mice and stimulated with L. (L.) amazonensis amastigotes extract and active TGF-β was evaluated in supernatants of foot lesions; both dosages were carried out by means of a double-sandwich ELISA assay. A significant increase of TCD4+ and TCD8+ lymphocytes and IFN-γ secretion was displayed in mice treated with DPPE 1.1 compared to untreated animals, whereas a significant reduction of active TGF-β was observed in treated mice. These findings open perspectives for further investment in DPPE 1.1 as an alternative option for the chemotherapy of cutaneous leishmaniasis

    SECAS E OS IMPACTOS NA REGIÃO SUL DO BRASIL

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    Embora eventos de secas sejam menos frequentes na Região Sul, se comparado com outras regiões do Brasil, quando ocorrem impactam o abastecimento de água, produção agrícola e a geração de energia elétrica. Portanto, a avaliação dos impactos da seca no setor agrícola e nos recursos hídricos, são de extrema importância para a gestão de riscos nesta região. Neste estudo avaliou-se os principais eventos de secas e seus impactos entre 1998 a 2020 (maio) na Região Sul do Brasil. Para isto, foram utilizados índices de secas calculados a partir de dados de precipitação, vazão e dados derivados de satélite. De acordo com o Índice de Precipitação Padronizada (SPI), o evento mais severo de seca ocorreu no estado do Paraná em 2006. Como consequência, registrou-se valores de área agro-produtivas afetada acima de 80% e seca hidrológica excepcional na bacia hidrográfica afluente (BHA) à usina hidrelétrica (UHE) Segredo, segundo o Índice de Vazão Padronizada (SSFI), além de vazões afluentes abaixo do percentil 90 durante 50% do ano. Em Santa Catarina e no Rio Grande do Sul, os eventos de secas de maior severidade ocorreram em 2012/2013. Apesar disso, os percentuais de áreas agro-produtivas afetadas foram inferiores aos verificados para 2019/2020. Com relação aos recursos hídricos, o SSFI indicou seca excepcional na BHA ao reservatório da UHE Passo Real, e foi observada vazão abaixo do percentil 90 no primeiro semestre de 2012. No evento de seca 2019/2020, o primeiro trimestre de 2020 foi o mais crítico em termos de intensidade e expansão, como mostrado pelo Índice Integrado de Seca, em que 100% dos municípios de toda a região foram classificados em condição de seca. O impacto deste evento pode ser observado pelo SSFI da BHA ao reservatório da UHE Itaipu, com menores valores registrados a partir de janeiro de 2020. Este evento pode estar associado à influência da fase negativa da Oscilação Decadal do Pacífico e condições de neutralidade no Pacífico Equatorial

    Autoimmune hepatitis in 828 Brazilian children and adolescents: clinical and laboratory findings, histological profile, treatments, and outcomes

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    In this large clinical series of Brazilian children and adolescents, autoimmunehepatitis-1 was more frequent, and patients with autoimmune hepatitis-2 exhibited higherdisease remission rates with earlier response to treatment. Patients with autoimmune hepatitis-1 had a higher risk of death.sentation, laboratory findings, histological profile, treatments, and outcomes of children andadolescents with autoimmune hepatitis.Methods: The medical records of 828 children and adolescents with autoimmune hepatitiswere reviewed. A questionnaire was used to collect anonymous data on clinical presentation,biochemical and histological findings, and treatments.Results: Of all patients, 89.6% had autoimmune hepatitis-1 and 10.4% had autoimmunehepatitis-2. The female sex was predominant in both groups. The median age at symptomonset was 111.5 (6; 210) and 53.5 (8; 165) months in the patients with autoimmune hepatitis1 and autoimmune hepatitis-2, respectively. Acute clinical onset was observed in 56.1% and58.8% and insidious symptoms in 43.9% and 41.2% of the patients with autoimmune hepatitis-1and autoimmune hepatitis-2, respectively. The risk of hepatic failure was 1.6-fold higher forautoimmune hepatitis-2. Fulminant hepatic failure occurred in 3.6% and 10.6% of the patientswith autoimmune hepatitis-1 and autoimmune hepatitis-2, respectively; the risk was 3.1-foldhigher for autoimmune hepatitis-2. The gamma globulin and immunoglobulin G levels were sig-nificantly higher in autoimmune hepatitis-1, while the immunoglobulin A and C3 levels werelower in autoimmune hepatitis-2. Cirrhosis was observed in 22.4% of the patients; biochem-ical remission was achieved in 76.2%. The actuarial survival rate was 93.0%. A total of 4.6%underwent liver transplantation, and 6.9% died (autoimmune hepatitis-1: 7.5%; autoimmunehepatitis-2: 2.4%).Conclusions: In this large clinical series of Brazilian children and adolescents, autoimmunehepatitis-1 was more frequent, and patients with autoimmune hepatitis-2 exhibited higherdisease remission rates with earlier response to treatment. Patients with autoimmune hepatitis-1 had a higher risk of death.info:eu-repo/semantics/publishedVersio
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