783 research outputs found

    Effect of temperature on the electro-oxidation of ethanol on platinum

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    We present in this work an experimental investigation of the effect of temperature (from 25 to 180 ºC) in the electro-oxidation of ethanol on platinum in two different phosphoric acid concentrations. We observed that the onset potential for ethanol electro-oxidation shifts to lower values and the reaction rates increase as temperature is increased for both electrolytes. The results were rationalized in terms of the effect of temperature on the adsorption of reaction intermediates, poisons, and anions. The formation of oxygenated species at high potentials, mainly in the more diluted electrolyte, also contributes to increase the electro-oxidation reaction rate.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Pesquisa (CNPq

    Tandem X-ray absorption spectroscopy and scattering forin situtime-resolved monitoring of gold nanoparticle mechanosynthesis

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    Current time-resolvedin situapproaches limit the scope of mechanochemical investigations possible. Here we develop a new, general approach to simultaneously follow the evolution of bulk atomic and electronic structure during a mechanochemical synthesis. This is achieved by coupling two complementary synchrotron-based X-ray methods: X-ray absorption spectroscopy (XAS) and X-ray diffraction. We apply this method to investigate the bottom-up mechanosynthesis of technologically important Au micro and nanoparticles in the presence of three different reducing agents, hydroquinone, sodium citrate, and NaBH4. Moreover, we show how XAS offers new insight into the early stage generation of growth species (e.g.monomers and clusters), which lead to the subsequent formation of nanoparticles. These processes are beyond the detection capabilities of diffraction methods. This combined X-ray approach paves the way to new directions in mechanochemical research of advanced electronic materials.Peer reviewe

    Escorpiones venenosos encontrados en Corrientes y Chaco. Características de la intoxicación

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    Mediante el proyecto de Voluntariado Universitario “Alerta roja: escorpiones!” aprobado por la SPU, hemos realizado charlas, recorridas y trabajos de laboratorio en Corrientes y Chaco, alertando sobre la toxicidad de los escorpiones, la forma de reconocer especies tóxicas, medidas de prevención y profilaxis. Asimismo se capturaron ejemplares para su identificación y estudio posterior. Hemos encontrado las especies de escorpiones venenosos Tityus trivittatus y T. Confluens en Corrientes y Chaco, extraído su veneno (promedio 0,26 y 0,21 mg por ejemplar respectivamente) y analizado la casuística de accidentes particularmente en Puerto Vilelas (Chaco) encontrando que el 100 % refería dolor en el accidente, no requiriéndose en ninguno de los casos la derivación a centros de mayor complejidad.

    Validación del uso tradicional de especies de Asclepias contra el veneno de Bothrops diporus (yarará chica) en el Nordeste de Argentina

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    La familia Asclepiadaceae posee tradición en etnomedicina. En el nordeste argentino, A.mellodora y A. curassavica se utilizan como cataplasmas en accidentes de ofidios. En este trabajo, los extractos acuosos, etanólicos y hexánicos de A. mellodora y A. curassavica se evaluaron por SDS-PAGE para determinar su actividad alexitérica. El estudio in vitro de la capacidad inhibitoria de las actividades proteolítica, hemolítica indirecta y coagulante permitieron determinar que ambas especies manifiestan actividad, siendo A. mellodora más activa. Estadísticamente los extractos de A. mellodora fueron igualmente activos contra el veneno de Bothrops diporus y no mostraron diferencias significativas respecto del órgano utilizado en la inhibición de la actividad coagulante. Este resultado está en consonancia con la forma tradicional de su uso como cataplasma. Sobre el extracto etanólico de las raíces de A. mellodora se realizó un fraccionamiento bioguiado que permitió identificar fracciones de compuestos responsables de la actividad

    PTX3-based genetic testing for risk of aspergillosis after lung transplant

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    [Excerpt] We read with interest the article by Wójtowicz et al [1], and would like to comment on it and to share findings from our complementary study. We have recently established genetic variation in the long pentraxin 3 (PTX3) as a major determinant of susceptibility to invasive aspergillosis (IA) after hematopoietic stem cell transplant [2]. Wójtowicz et al are the first to uncover similar findings in solid organ transplant (SOT) recipients, highlighting a potential applicability of these markers in predicting infection across patients with intrinsically different predisposing conditions (...).ESCMID -European Society of Clinical Microbiology and Infectious Diseases(undefined

    Influencia del género en las formas de participación femenina en los proyectos productivos de Hueyapan, Morelos, México

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    In this article, we consider the relationship between productiveand cultural aspects within a framework of rural developmentwith gender perspective. The backdrop is the community ofHueyapan, Morelos, where the population speaks Nahuatl andpreserves its customs and traditions. The hypothesis was thatproductive projects in which women participate are influencedby gender roles in their success or failure. The methodology usedwas based on a qualitative approach and the techniques were:literature review, participative observation, semi-structuredinterviews, life histories and workshops. The conclusions indicatethat traditional gender stereotypes (in regards to division of labor,couple relationships and kinship relationships) influence women'sparticipation in projects. A successful experience in participationpositively influences the rearrangement of gender patterns, makingthem more flexible for women and men.En el presente trabajo se reflexiona sobre la relación entre losaspectos productivos y culturales, dentro del marco del desarrollorural con perspectiva de género. El escenario es la comunidadde Hueyapan, Morelos, su población habla nahuatl y conservasus costumbres y tradiciones. La hipótesis planteada es que losproyectos productivos en que participan las mujeres son influenciadosen su éxito o fracaso por los roles de género. La metodologíaempleada se basó en un enfoque cualitativo y las técnicasfueron: revisión bibliográfica, observación participante, entrevistasemi estructurada, historia de vida y talleres. Las conclusionesindican que los estereotipos tradicionales de género (relativosa la división del trabajo, las relaciones de pareja y las relacionesde parentesco) influyen en la participación de las mujeresen los proyectos. La experiencia exitosa de participación influyepositivamente en el reacomodo de los patrones de género haciéndolosmás flexibles para mujeres y hombres

    Low-level Laser Therapy to the Mouse Femur Enhances the Fungicidal Response of Neutrophils against Paracoccidioides brasiliensis

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    Neutrophils (PMN) play a central role in host defense against the neglected fungal infection paracoccidioidomycosis (PCM), which is caused by the dimorphic fungus Paracoccidioides brasiliensis (Pb). PCM is of major importance, especially in Latin America, and its treatment relies on the use of antifungal drugs. However, the course of treatment is lengthy, leading to side effects and even development of fungal resistance. the goal of the study was to use low-level laser therapy (LLLT) to stimulate PMN to fight Pb in vivo. Swiss mice with subcutaneous air pouches were inoculated with a virulent strain of Pb or fungal cell wall components (Zymosan), and then received LLLT (780 nm; 50 mW; 12.5 J/cm2; 30 seconds per point, giving a total energy of 0.5 J per point) on alternate days at two points on each hind leg. the aim was to reach the bone marrow in the femur with light. Non-irradiated animals were used as controls. the number and viability of the PMN that migrated to the inoculation site was assessed, as well as their ability to synthesize proteins, produce reactive oxygen species (ROS) and their fungicidal activity. the highly pure PMN populations obtained after 10 days of infection were also subsequently cultured in the presence of Pb for trials of protein production, evaluation of mitochondrial activity, ROS production and quantification of viable fungi growth. PMN from mice that received LLLT were more active metabolically, had higher fungicidal activity against Pb in vivo and also in vitro. the kinetics of neutrophil protein production also correlated with a more activated state. LLLT may be a safe and non-invasive approach to deal with PCM infection.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)National Institute of Health (US NIH)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fed Univ Alfenas UNIFAL MG, Inst Biomed Sci, Dept Microbiol & Immunol, Alfenas, MG, BrazilFed Univ Alfenas UNIFAL MG, Inst Biomed Sci, Dept Biochem, Alfenas, MG, BrazilState Univ Campinas UNICAMP, Inst Biol, Dept Struct & Funct Biol, São Paulo, BrazilFed Univ São Paulo UNIFESP, Dept Microbiol Immunol & Parasitol, São Paulo, SP, BrazilMassachusetts Gen Hosp, Wellman Ctr Photomed, Boston, MA 02114 USAHarvard Univ, Sch Med, Dept Dermatol, Boston, MA 02115 USAMIT, Harvard Mit Div Hlth Sci & Technol, Cambridge, MA 02139 USAFed Univ Alfenas UNIFAL MG, Inst Biomed Sci, Dept Pathol & Parasitol, Alfenas, MG, BrazilFed Univ São Paulo UNIFESP, Dept Microbiol Immunol & Parasitol, São Paulo, SP, BrazilCNPq: 486135/2012-8CNPq: 304827/2012-6FAPEMIG: CBB-PPM-00119-14National Institute of Health (US NIH): R01AI050875CAPES: AEX-9765-14-0Web of Scienc

    Endosymbiosis in trypanosomatids: the genomic cooperation between bacterium and host in the synthesis of essential amino acids is heavily influenced by multiple horizontal gene transfers

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    Background Trypanosomatids of the genera Angomonas and Strigomonas live in a mutualistic association characterized by extensive metabolic cooperation with obligate endosymbiotic Betaproteobacteria. However, the role played by the symbiont has been more guessed by indirect means than evidenced. Symbiont-harboring trypanosomatids, in contrast to their counterparts lacking symbionts, exhibit lower nutritional requirements and are autotrophic for essential amino acids. To evidence the symbiont’s contributions to this autotrophy, entire genomes of symbionts and trypanosomatids with and without symbionts were sequenced here. Results Analyses of the essential amino acid pathways revealed that most biosynthetic routes are in the symbiont genome. By contrast, the host trypanosomatid genome contains fewer genes, about half of which originated from different bacterial groups, perhaps only one of which (ornithine cyclodeaminase, EC:4.3.1.12) derived from the symbiont. Nutritional, enzymatic, and genomic data were jointly analyzed to construct an integrated view of essential amino acid metabolism in symbiont-harboring trypanosomatids. This comprehensive analysis showed perfect concordance among all these data, and revealed that the symbiont contains genes for enzymes that complete essential biosynthetic routes for the host amino acid production, thus explaining the low requirement for these elements in symbiont-harboring trypanosomatids. Phylogenetic analyses show that the cooperation between symbionts and their hosts is complemented by multiple horizontal gene transfers, from bacterial lineages to trypanosomatids, that occurred several times in the course of their evolution. Transfers occur preferentially in parts of the pathways that are missing from other eukaryotes. Conclusion We have herein uncovered the genetic and evolutionary bases of essential amino acid biosynthesis in several trypanosomatids with and without endosymbionts, explaining and complementing decades of experimental results. We uncovered the remarkable plasticity in essential amino acid biosynthesis pathway evolution in these protozoans, demonstrating heavy influence of horizontal gene transfer events, from Bacteria to trypanosomatid nuclei, in the evolution of these pathways

    Comparison of the neuropsychological assessment in a girl with bilateral cerebrovascular disease (moyamoya) before and after surgical intervention

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    Moyamoya is a chronic progressive cerebrovascular disease with characteristic angiographic findings and a clinical picture with episodes of transient ischemic attacks, headache, seizures, hemiparesis, which may resolve after surgical treatment. We describe the case of a girl with the typical findings of the disease, comparing them before and after surgery with the use of neuropsychological tests, neurological examination and laboratory tests.A doença de moyamoya é anormalidade cerebrovascular crônica e progressiva identificada através das características angiográficas; estão presentes no quadro clínico episódios isquêmicos transitórios, cefaléia, crises convulsivas, hemiparesia, que podem desaparecer após tratamento cirúrgico. Nós descrevemos o caso de uma menina com características clássicas da doença, comparando-o em dois momentos, antes e depois da cirurgia, através de avaliações neurológicas, neuropsicológicas, e exames complementares.1036104
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