1,948 research outputs found

    Sustainable Production of Hydrogen by Steam Reforming of Ethanol Using Cobalt Supported on Nanoporous Zeolitic Material

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    [EN] Cobalt catalysts supported on Y zeolite and mesoporized Y zeolite (Y-mod) have been studied in steam reforming of ethanol (SRE). Specifically, the effect of the mesoporosity and the acidity of the y zeolite as a support has been explored. Mesoporous were generated on Y zeolite by treatment with NH4F and the acidity was neutralized by Na incorporation. Four cobalt catalysts supported on Y zeolite have been prepared, two using Y zeolite without mesoporous (Co/Y, Co/Y-Na), and two using Y zeolite with mesoporous (Co/Y-mod and Co/Y-mod-Na). All catalysts showed a high activity, with ethanol conversion values close to 100%. The main differences were found in the distribution of the reaction products. Co/Y and Co/Y-mod catalysts showed high selectivity to ethylene and low hydrogen production, which was explained by their high acidity. On the contrary, neutralization of the acid sites could explain the higher hydrogen selectivity and the lower ethylene yields exhibited by the Co/Y-Na and Co/Y-mod-Na. In addition, the physicochemical characterization of these catalysts by XRD, BET surface area, temperature-programmed reduction (TPR), and TEM allowed to connect the presence of mesoporous with the formation of metallic cobalt particles with small size, high dispersion, and with high interaction with the zeolitic support, explaining the high reforming activity exhibited by the co/y-mod-Na sample as well as its higher hydrogen selectivity. It has been also observed that the formation of coke is affected by the presence of mesoporous and acidity. Both properties seem to have an opposite effect on the reforming catalyst, decreasing and increasing the coke deposition, respectively.This research was funded by Generalitat Valenciana, grant number PROMETEO/2018/006", Spanish Government (Project RTI2018-102161-I00) and RED DE EXCELENCIA EN BIORREFINERIAS SOSTENIBLES (RED2018-102623-T).Da Costa Serra, JF.; Navarro, MT.; Rey Garcia, F.; Chica, A. (2020). Sustainable Production of Hydrogen by Steam Reforming of Ethanol Using Cobalt Supported on Nanoporous Zeolitic Material. Nanomaterials. 10(10):1-13. https://doi.org/10.3390/nano10101934S113101

    Functional genomics and expression analysis of the Corynebacterium glutamicum fpr2-cysIXHDNYZ gene cluster involved in assimilatory sulphate reduction

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    Rückert C, Koch DJ, Rey DA, et al. Functional genomics and expression analysis of the Corynebacterium glutamicum fpr2-cysIXHDNYZ gene cluster involved in assimilatory sulphate reduction. BMC Genomics. 2005;6(1): 121.Background: Corynebacterium glutamicum is a high-GC Gram-positive soil bacterium of great biotechnological importance for the production of amino acids. To facilitate the rational design of sulphur amino acid-producing strains, the pathway for assimilatory sulphate reduction providing the necessary reduced sulfur moieties has to be known. Although this pathway has been well studied in Gram-negative bacteria like Escherichia coli and low-GC Gram-positives like Bacillus subtilis, little is known for the Actinomycetales and other high-GC Gram-positive bacteria. Results: The genome sequence of C. glutamicum was searched for genes involved in the assimilatory reduction of inorganic sulphur compounds. A cluster of eight candidate genes could be identified by combining sequence similarity searches with a subsequent synteny analysis between C. glutamicum and the closely related C. efficiens. Using mutational analysis, seven of the eight candidate genes, namely cysZ, cysY, cysN, cysD, cysH, cysX, and cysI, were demonstrated to be involved in the reduction of inorganic sulphur compounds. For three of the up to now unknown genes possible functions could be proposed: CysZ is likely to be the sulphate permease, while CysX and CysY are possibly involved in electron transfer and cofactor biosynthesis, respectively. Finally, the candidate gene designated fpr2 influences sulphur utilisation only weakly and might be involved in electron transport for the reduction of sulphite. Real-time RT-PCR experiments revealed that cysIXHDNYZ form an operon and that transcription of the extended cluster fpr2 cysIXHDNYZ is strongly influenced by the availability of inorganic sulphur, as well as L-cysteine. Mapping of the fpr2 and cysIXHDNYZ promoters using RACE-PCR indicated that both promoters overlap with binding-sites of the transcriptional repressor McbR, suggesting an involvement of McbR in the observed regulation. Comparative genomics revealed that large parts of the extended cluster are conserved in 11 of 17 completely sequenced members of the Actinomycetales. Conclusion: The set of C. glutamicum genes involved in assimilatory model organisms E. coli and B. subtilis is used by members of this order, providing the basis for further biochemical studies.sulphate reduction was identified and four novel genes involved in this pathway were found. The high degree of conservation of this cluster among the Actinomycetales supports the hypothesis that a different metabolic pathway for the reduction of inorganic sulphur compounds than that known from the well-studied model organisms E. coli and B. subtilis is used by members of this order, providing the basis for further biochemical studies

    Immunohistological Biomarkers of Toxicity by a Pharmaceutical Antidepressant in the Freshwater Cichlid Fish Cichlasoma dimerus (Teleostei, Cichliformes)

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    Melano-macrophage centers (MMCs) are nodular clusters of pigmented macrophages, implicated in homeostasis and destruction and recycling of endogenous and exogenous material. They can increase in size and/or frequency under environmental stress resulting in immunohistological biomarkers of water quality. Fluoxetine (FLX), a commonly prescribed antidepressant, can cause neuroendocrine, behavioral and reproductive alterations in teleost fish. In the present study, we analyzed the effects of a 2-week 50 µg/L FLX exposure on MMCs in histological sections of spleen and head-kidney (HK) of the cichlid fish Cichlasoma dimerus. In the spleen, FLX caused an increase in the area and a decrease in the number of MMCs. An increase in the proportion of the HK occupied by MMCs was observed in FLX-exposed fish, due to an increase in their number but not their area. The deposition rate of MMCs varies according to the hemolymphopoietic organ and would be the result of a differential response to FLX on homeostatic functions (elimination of cellular debris, iron processing and immune response).Fil: Rey Vázquez, Graciela. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Da Cuña, Rodrigo Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentina. Universidad de Buenos Aires; ArgentinaFil: Dorelle, Luciana Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentina. Universidad de Buenos Aires; ArgentinaFil: Lo Nostro, Fabiana Laura. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentin

    U–Pb and Sm–Nd geochronology of amphibolites from the Curaçá Belt, São Francisco Craton, Brazil : tectonic implications

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    The Curaçá terrane is part of the Itabuna–Salvador–Curaçá (I–S–C) Paleoproterozoic orogen in the São Francisco craton, northeastern Brazil, and comprises supracrustal rocks, gneisses of their probable basement, amphibolites, and mafic-ultramafic Cu-bearing bodies (including the Caraíba Cu-Mine), all affected by D1-D3 deformation events associated to M1-M3 metamorphism under high-T granulite and amphibolite facies, and assisted by G1-G3 tonalitic-granodioritic-granitic intrusions. U–Pb and Sm–Nd Thermal Ionization Mass Spectrometry (TIMS) isotopic data from amphibolite, tonalite, and granite, sampled in a well-known outcrop, indicate partial reset and heterogeneous modification of the original isotopic systems, attributable to deformation and metamorphism. The ages obtained from these systems agree with each other, and also with other previously published U–Pb data, and imply that 2.6 Ga is the crystallization age of the protolith of the amphibolite. Together with key structural relationships, they also indicate a 2.08–2.05 Ga interval for M3 metamorphism, and make even a less precise age (2.2–2.3 Ga) acceptable, as it suggests contamination in the amphibolite with material in a syn-D2 tonalite crystallized 2248±36 Ma ago. The new data demonstrate the existence of Neoarchean fragments of both oceanic and continental crusts and constrain the Archean-Paleoproterozoic development of the Curaçá belt, the I–S–C orogen, and the São Francisco craton

    Exponential Mixing for a Stochastic PDE Driven by Degenerate Noise

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    We study stochastic partial differential equations of the reaction-diffusion type. We show that, even if the forcing is very degenerate (i.e. has not full rank), one has exponential convergence towards the invariant measure. The convergence takes place in the topology induced by a weighted variation norm and uses a kind of (uniform) Doeblin condition.Comment: 10 pages, 1 figur

    Cistoscopia no diagnóstico e seguimento de esquistossomose urinária em militares brasileiros retornando de Moçambique, África

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    The assessment of urinary schistosomiasis in individuals coming from endemic areas often requires diagnostic resources not used in areas of exposure in order to determine complications or to establish more precise criteria of cure. Cystoscopy and 24-hour urine examination were performed, after treatments with praziquantel 40 mg/kg body weight, single dose, on 25 Brazilian military men who were part of a United Nations peace mission to Mozambique in 1994. The median age of the individuals was 29 years and all presented a positive urine parasitological exam. The alterations detected by cystoscopy were hyperemia and granulomas in the vesical submucosa in 59.1% of the individuals and only granulomas in 40.9%. A vesical biopsy revealed granulomas in all patients and viable eggs in 77.3% even after a period during which the patients no longer excreted eggs in urine. Cystoscopy after treatment, followed by biopsy and histopathological evaluation, performed in areas where the evolution of the disease can be better monitored, was found to be a safe criterion of parasitological cure.A avaliação de esquistossomose urinária em indivíduos procedentes de áreas endêmicas, freqüentemente requer recursos diagnósticos não usados nas áreas de exposição, para determinar as complicações ou estabelecer um critério de cura mais preciso. A cistoscopia e o exame de urina de 24 horas foram realizados, após tratamentos com praziquantel na dose de 40 mg/kg de peso, dose única, em 25 militares brasileiros que participaram de uma Missão de Paz pela ONU em Moçambique no ano de 1994. A idade média dos indivíduos foi de 29 anos e todos apresentavam exame parasitológico de urina positivo. As alterações detectadas pela cistoscopia foram hiperemia e granulomas na submucosa vesical em 59.1% dos indivíduos e somente granulomas em 40.9%. A biópsia vesical revelou granulomas em todos os pacientes e ovos viáveis em 77.3%, mesmo após um período durante o qual os pacientes não mais eliminavam ovos pela urina. Após o tratamento, a cistoscopia seguida por biópsia e avaliação histopatológica, realizada em áreas onde a evolução da doença pode ser monitorada melhor, demonstrou ser um critério mais seguro de cura parasitológica

    Cochlear implant and large vestibular aqueduct syndrome in children

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    Crianças com SAVA podem ter deficiências auditivas moderadas a severas durante fases precoces da infância, porém sua audição residual permite que elas desenvolvam linguagem oral com aparelhos auditivos convencionais e possam estar completamente integradas a condições escolares regulares. Contudo, estas crianças apresentam uma deterioração de sua habilidade auditiva com o decorrer do tempo e o implante coclear está sendo utilizado como uma opção para manter a habilidade auditiva. OBJETIVO: Avaliação da habilidade auditiva de 3 crianças com SAVA submetidas a implante coclear. MATERIAIS: Estudo retrospectivo baseado em revisão de prontuários. RESULTADOS: Em reconhecimento de palavras em campo aberto paciente 1, 80%, paciente 2, 87,5%, paciente 3, 4%. CONCLUSÃO: Os pacientes com aqueduto vestibular alargado são considerados bons candidatos para implante coclear pelos principais centros de implante coclear do mundo, por desenvolverem, em sua maioria, bons resultados de percepção de fala, o que leva estes pacientes a uma boa inserção social.Children with LVAS can develop a severe sensorineural hearing loss early in childhood, but they can be rehabilitated with hearing aids to continue their regular studies and to have a normal life. The problem is that they can deteriorate their hearing capacity, and at this point a cochlear implant can be used to preserve their hearing skills and vocalization. AIM: to evaluate the hearing skills of 3 children with LVAS referred to cochlear implants. MATERIAL: retrospective study based on medical charts' review. RESULTS: Speech recognition in open field: patient 1, 80%; patient 2, 87.5%; patient 3, 4 %. CONCLUSION: Children with LVAS are considered good candidates for Cochlear implant surgery by the most important centers of the world because most of them can develop good speech recognition, providing them a good social life

    DIAGNÓSTICO INTEGRAL DEL ÁREA DE INFLUENCIA DE LA UNIVERSIDAD NACIONAL DE LUJÁN. Una herramienta para la gestión.

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    Se presenta en esta ponencia el trabajo de configuración del programa “DIAGNÓSTICO INTEGRAL DEL AREA DE INFLUENCIA DE LA UNIVERSIDAD NACIONAL DE LUJAN: Evaluación e impacto de acciones y servicios hacia la comunidad”. La labor en equipo, que está avalada por disposición 688/06 del Consejo Directivo Departamental de Ciencias Sociales de la Universidad Nacional de Luján (UNLu.), tiene como meta perfilar el área de influencia de la UNLu para establecer un diagnóstico de los territorios involucrados, y evaluar las acciones y servicios realizados desde el ámbito universitario. A partir de la caracterización de la relación universidad-área de influencia, se delinearán distintas tácticas de base para la planificación y gestión de servicios a la comunidad. Los servicios se pensarán en función de las demandas de los distintos sectores sociales: extrínsecos (comunidad) e intrínsecos (UNLu). Se da cuenta también aquí, del sistema de relaciones entre los distintos proyectos del programa que intentan dimensionar la vinculación entre: • crecimiento vegetativo de la población y crecimiento vegetativo del alumnado; • creación de carreras y necesidades de la comunidad; • sistema de transporte y servicios académicos; • investigación y desarrollo local; • extensión y vinculación sectorial

    The expression of creativity in learning how to read and write : a case study

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    O presente artigo tem por objetivo destacar as formas em que a criatividade se expressa na aprendizagem da leitura e da escrita da criança. Assume-se como referencial teórico a concepção de aprendizagem criativa desenvolvida por Mitjáns Martínez. Segundo essa concepção, os processos criativos emergem nos contextos de ação do sujeito, mediante recursos subjetivos constituídos historicamente e que se organizam no momento da ação concreta. A expressão desse tipo de aprendizagem tem se configurado pela personalização da informação, confrontação com o dado e pela geração, produção de ideias novas que vão além do que está posto. Adota-se como eixo norteador a pesquisa qualitativa, apoiada nos princípios da epistemologia qualitativa desenvolvida por González Rey, com opção pelo estudo de caso utilizando instrumentos abertos e semiabertos, tais como: dinâmicas conversacionais, observações, entrevistas como processo e diário de ideias. A investigação foi desenvolvida em uma escola da rede pública, com alunos dos primeiros e segundos anos do ensino fundamental, na qual acompanhamos os aprendizes por dois anos consecutivos. Como conclusão, considera-se que a expressão da criatividade na aprendizagem da leitura e da escrita foi significativamente apresentada pelas características destacadas por Mitjáns Martínez, bem como pela relação lúdica da criança com sua aprendizagem.This paper has the purpose of highlighting the ways through which creativity is expressed in the child´s learning of how to read and write. The theoretical assumption taken is the concept of creative learning developed by Mitjáns Martínez. According to such conception, the creative processes emerge in the context of the individual´s action, through subjective resources that are historically constructed and are organized in the moment of concrete action. The expression of this type of learning has been configured by the personalization of information, confrontation with the data, and by the generation and production of new ideas that go beyond what is taken for granted. The guiding axis adopted is qualitative research, supported by the principles of thequalitative epistemology developed by González Rey, with the option of conducting a case study utilizing open and semi-open tools, such as: conversational dynamics, observations, interviews as a process and a diary of ideas. The investigation took place in a public school, among 1st and 2nd graders, in which we monitored the learners for two years in a row. As a conclusion, we consider that the expression of creativity in learning how to read and write was significantly presented by the characteristics emphasized by the author mentioned above, as well as by the playful relationship of the child with his/her learning

    Parâmetros genéticos para características de crescimento e reprodução de bovinos da raça Canchim.

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    O objetivo deste trabalho foi estimar parâmetros genéticos para idades ao primeiro (IPP) e segundo partos (ISP), idades ao primeiro (IPP PEN) e segundo partos penalizadas (ISP PEN), e a ocorrência de parto até os 38 meses de idade (PP38), em bovinos da raça Canchim, bem como estimar as relações genéticas entre essas características e o peso (PE420) de machos e femêas e a circunferência escrotal (CE420) de novilhos, medidos aos 420 dias de idade. Foram estimados parâmetros genéticos em análises bicaracterísticas, por meio de inferência bayesiana. As análises foram realizadas entre CE420 e PE420 e as características reprodutivas medidas em fêmeas. As características reprodutivas das fêmeas devem apresentar baixa resposta à seleção, e mudanças no manejo e nas condições ambientais melhoram tais características. A seleção quanto ao maior peso aos 420 dias de idade não deve provocar mudanças nas características reprodutivas em fêmeas, enquanto a seleção para o aumento da circunferência escrotal, na mesma idade, contribui para melhorar tais características
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