127 research outputs found

    Anaerobic co-digestion of sugarcane vinasse and elephant grass juice for biomethan production.

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    In the present study, biogas production was investigated by co-digesting elephant grass juice (EGJ) and sugarcane vinasse using batch reactor. Some factors that influence biomethane production were observed, including initial pH, inoculum concentration and proportions of each substrate. Two tests were carried out. In Experiment I, the following proportions (%v/v sugarcane vinasse/elephant grass juice) were tested: A - 25/75, B - 50/50, C - 75/25, D - 100/0, E - 0/100. In Experiment II, the effect of adding alkalizer to the condition that showed the highest methane production (in Experiment I) was also evaluated. In the Experiment I, the highest accumulated production was observed for the proportion 1:1 corresponding to 50% of EGJ and 50% of vinasse (370.94 mLCH4/gVS). Experiment II showed the higher values of accumulated methane production of 1,364.1 mLCH4/gVS. Regarding addition of alkalizing, a maximum production of 836.18 mLCH4/gVS was obtained in the experimental condition with 50% EGJ and 50% vinasse, but with the lowest addition of alkalizer tested (0.05 g HCO3/gCOD). In general, the use of elephant grass caused the acidification of the reactors and was unfavorable for biogas production

    Inovação tecnológica como agente de redução de impactos ambientais da indústria de rochas ornamentais no estado do Rio de Janeiro

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    A indústria de rochas ornamentais da região noroeste fluminense constitui um arranjo produtivo local de grande importância econômica. Entretanto, as empresas fazem uso de técnicas rudimentares em seus processos produtivos, o que causa sérios problemas ambientais e de competitividade. Cientes de que a principal dificuldade enfrentada por esta indústria está relacionada com a ausência de tecnologias, governo, universidades e organizações da sociedade civil têm tentado desenvolver e difundir tecnologias. O objetivo deste trabalho de pesquisa é identificar e descrever os fatores que impedem a difusão de tecnologia neste arranjo produtivo. Foram realizados múltiplos estudos de caso de caráter exploratório, descritivo e explicativo, nos quais foram utilizadas múltiplas fontes de evidência, tais como revisão bibliográfica, entrevistas semi-estruturadas com empresários e profissionais do setor, além de visitas técnicas a empresas locais. Os resultados apontam para dificuldades na difusão dessas tecnologias, especialmente para as pequenas empresas, tais como baixa qualificação de empresários e trabalhadores, resistência a mudanças dentro das empresas, e dificuldade de articulação, já que, atualmente, existe disponibilidade de recursos financeiros e apoio institucional para a inovação

    Exploring metabolic responses of potato tissue induced by electric pulses

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    In this study, we investigated the metabolic responses of potato tissue induced by pulsed electric field (PEF). Potato tissue was subjected to field strengths ranging from 30 to 500 V/cm, with a single rectangular pulse of 10 μs, 100 μs, or 1 ms. Metabolic responses were monitored using isothermal calorimetry, changes on electrical resistance during the delivery of the pulse, as well as impedance measurements. Our results show that the metabolic response involves oxygen consuming pathways as well as other unidentified events that are shown to be insensitive to metabolic inhibitors such as KCN and sodium azide. The metabolic response is strongly dependent on pulsing conditions and is independent of the total permeabilization achieved by the pulse. Evidence shows that calorimetry is a simple and powerful method for exploring conditions for metabolic stimulation, providing information on metabolic responses that can not be obtained from electrical measurements. This study set the basis for further investigations on defense-related consequences of PEF-induced stress.Sparbanksstiftelsen Färs & Frosta (Sweden).Fundação para a Ciência e a Tecnologia (FCT).Lund University (Sweden).Department of Cell and Organism Biology; Department of Plant Biochemistry

    Planejamento e gestão do processo de trabalho em saúde: avanços e limites no Subsistema de Atenção à Saúde Indígena do SUS

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    The Indigenous Health Care Subsystem (SasiSUS), as part of the Brazilian National Health System (SUS), is responsible for health care for indigenous peoples in Brazil. At the local level, the Special Indigenous Health Districts (DSEI) are responsible for managing, planning, and organizing the work process of the multidisciplinary indigenous health teams (EMSI), which provide primary health care for this population. The objective of the study was to analyze how the planning and the management of the EMSI work process occurs. A holistic multiplecase study was carried out, considering seven DSEI as units of analysis. The main source of data used were interviews and, in a complementary way, direct observation. The results indicated that, in general, planning is present in the organization of the teams’ work process, with variations between the DSEI. Carrying out the planned actions was related to the availability of different resources: adequate functioning of the information system and the intra and intersectoral articulation of SasiSUS. As a conclusion, the need to radicalize participation in planning and management, necessary for a coordinated action to guarantee differentiated care and the principles of SUS, was pointed out.O Subsistema de Atenção à Saúde Indígena (SasiSUS), como parte do Sistema Único de Saúde (SUS), é responsável pela atenção à saúde dos povos indígenas do Brasil. Em âmbito local, são os Distritos Sanitários Especiais Indígenas (DSEI) os responsáveis pela gestão, planejamento e organização do processo de trabalho das equipes multidisciplinares de saúde indígena (EMSI), que realizam a atenção primária à saúde para essa população. O objetivo do estudo foi analisar como ocorrem o planejamento e a gestão do processo de trabalho das EMSI. Foi realizado um estudo de casos múltiplos holístico, considerando sete DSEI como unidades de análise. A principal fonte de dados utilizada foi a entrevista e, de forma complementar, a observação direta. Os resultados indicaram que, de forma geral, o planejamento está presente na organização do processo de trabalho das equipes, com variações entre os DSEI. A efetivação das ações planejadas foi relacionada à disponibilidade de diferentes recursos: funcionamento adequado do sistema de informação e a articulação intra e intersetorial do SasiSUS. Como conclusão, apontouse a necessidade de radicalização da participação no planejamento e na gestão, necessária a uma ação coordenada para garantia da atenção diferenciada e dos princípios do SUS

    Effects of pulsed electric field on the viscoelastic properties of potato tissue

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    We have investigated whether transient permeabilization caused by the application of pulsed electric field would give rise to transient changes in the potato tissue viscoelastic properties. Potato tissue was subjected to nominal field strengths (E) ranging from 30 to 500 V/cm, with a single rectangular pulse of 10−5, 10−4, or 10−3 s. The changes on the viscoelastic properties of potato tissue during pulsed electric fields (PEF) were monitored through small amplitude oscillatory dynamic rheological measurements. The elastic (G′) and viscous moduli (G″) were measured every 30 s after the delivery of the pulse and the loss tangent change (tan-δ) was calculated. The results were correlated with measurements of changes on electrical resistance during the delivery of the pulse. Results show a drastic increase of tan-δ in the first 30 s after the application of the pulse, followed by a decrease 1 min after pulsation. This response is strongly influenced by pulsing conditions and is independent of the total permeabilization achieved by the pulse. Our results, supported by similar measurements on osmotically dehydrated control samples, clearly show that PEF causes a rapid change of the viscoelastic properties of the tissue that could be attributed to a partial loss in turgor pressure. This would be an expected consequence of electroporation. The recovery of tan-δ to values similar to those before pulsation strongly suggests recovery of cell membrane properties and turgor, pointing at reversible permeabilization of the cells. A slight increase of stiffness traduced by a negative change of tan-δ after application of certain PEF conditions may also give an indication of events occurring on cell wall structure due to stress responses. This study set the basis for further investigations on the complex cell stress physiology involving both cell membrane functional properties and cell wall structure that would influence tissue physical properties upon PEF application.Fundação para a Ciência e a Tecnologia (FCT

    The two-pore channel TPCN2 mediates NAADP-dependent Ca2+-release from lysosomal stores

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    Second messenger-induced Ca2+-release from intracellular stores plays a key role in a multitude of physiological processes. In addition to 1,4,5-inositol trisphosphate (IP3), Ca2+, and cyclic ADP ribose (cADPR) that trigger Ca2+-release from the endoplasmatic reticulum (ER), nicotinic acid adenine dinucleotide phosphate (NAADP) has been identified as a cellular metabolite that mediates Ca2+-release from lysosomal stores. While NAADP-induced Ca2+-release has been found in many tissues and cell types, the molecular identity of the channel(s) conferring this release remained elusive so far. Here, we show that TPCN2, a novel member of the two-pore cation channel family, displays the basic properties of native NAADP-dependent Ca2+-release channels. TPCN2 transcripts are widely expressed in the body and encode a lysosomal protein forming homomers. TPCN2 mediates intracellular Ca2+-release after activation with low-nanomolar concentrations of NAADP while it is desensitized by micromolar concentrations of this second messenger and is insensitive to the NAADP analog nicotinamide adenine dinucleotide phosphate (NADP). Furthermore, TPCN2-mediated Ca2+-release is almost completely abolished when the capacity of lysosomes for storing Ca2+ is pharmacologically blocked. By contrast, TPCN2-specific Ca2+-release is unaffected by emptying ER-based Ca2+ stores. In conclusion, these findings indicate that TPCN2 is a major component of the long-sought lysosomal NAADP-dependent Ca2+-release channel
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