487 resultados para Chips


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Use of activated charcoal and ion-exchange resin to cleaN up and concentrate enzymes in extracts from biodegraded wood. Ceriporiopsis subvermispora was used for the biodegradation of Eucalyptus grandis chips in the presence or absence of co-substrates (glucose and corn steep liquor) during 7, 14 and 28 days. Afterwards, the biodegraded chips were extracted with 50 mM sodium acetate buffer (pH 5.5) supplemented with 0.01% Tween 60. High activities of manganese peroxidases (MnPs) were observed in all the extracts, both in the absence (430, 765 and 896 UI kg(-1) respectively) and in the presence of co-substrates (1,013; 2,066 and 2,323 UI kg(-1) respectively). The extracts presented a high ratio between absorbances at 280 and 405 nm, indicating a strong abundance of aromatic compounds derived from lignin over heme-peroxidases. Adsorption into activated charcoal showed to be an adequate strategy to reduce the absorbance at 280 urn in all the extracts. Moreover, it allowed to maximize the capacity of an anion exchange resin bed (DEAE-Sepharose) used to concentrate the MnPs present in the extracts. It was concluded that the use of activated charcoal followed by adsorption into DEAE Sepharose is a strategy that can be used to concentrate MnPs in extracts obtained during the biodegradation of E. grandis by C. subvermispora.

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Pinus taeda wood chips were treated with the biopulping fungus Ceriporiopsis subvermispora in soybean-oil-amended cultures The secretion of oxalic acid and the accumulation of thiobarbituric acid reactive substances were significantly increased in soybean-oil-amended cultures By contrast the secretion of hydrolytic and oxidative enzymes was not altered in the cultures Biotreated wood samples were characterized for weight and component losses as well as by in-situ thioacidolysis Residual lignins were also extracted from biotreated wood using a mild-non-razing extraction procedure The lignins were characterized by (31)P nuclear magnetic resonance ((31)P-NMR) spectroscopy Soybean oil amendment in the cultures was found to affect lignin degradation routes however it inhibited depolymerization reactions detectable in the residual lignin that was retained in the biotreated wood As a consequence chemithermomechanical pulping of the biotreated samples was not improved by soybean oil amendment in the cultures Crown Copyright (C) 2010 Published by Elsevier Ltd All rights reserved

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Ceriporiopsis subvermispora is a white-rot fungus used in biopulping processes and seems to use the fatty acid peroxidation reactions initiated by manganese-peroxidase (MnP) to start lignin degradation. The present work shows that C. subvermispora was able to peroxidize unsaturated fatty acids during wood biotreatment under biopulping conditions. In vitro assays showed that the extent of linoleic acid peroxidation was positively correlated with the level of MnP recovered from the biotreated wood chips. Milled wood was treated in vitro by partially purified MnP and linoleic acid. UV spectroscopy and size exclusion chromatography (SEC) showed that soluble compounds similar to lignin were released from the milled wood. SEC data showed a broad elution profile compatible with low molar mass lignin fractions. MnP-treated milled wood was analyzed by thioacidolysis. The yield of thioacidolysis monomers recovered from guaiacyl and syringyl units decreased by 33% and 20% in MnP-treated milled wood, respectively. This has suggested that lignin depolymerization reactions have occurred during the MnP/linoleic acid treatment. (C) 2009 Elsevier Inc. All rights reserved.

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In the present study, it was evaluated how two different culture conditions for the biotreatment of Eucalyptus grandis by Ceriporiopsis subvermispora affect a subsequent high-yield kraft pulping process. Under the varied culture conditions investigated, different extracellular enzyme activities were observed. Manganese-peroxidase (MnP) secretion was 3.7 times higher in cultures supplemented with glucose plus corn-steep liquor (glucose/CSL) as compared to non-supplemented (NS) cultures. The biotreated samples underwent diverse levels of wood component degradation as losses of weight and lignin were increased in glucose/CSL cultures. Mass balances for lignin removal during kraft pulping showed that delignification was facilitated when both biotreated wood samples were cooked. Delignification efficiency did not correlate positively with MnP levels in the cultures. On the other hand, biopulps from NS and glucose/CSL cultures saved 27% and 38% beating time to achieve 288 Schopper-Riegler freeness during refining, respectively. Biopulps disposed of decreased tensile and tear resistances, thus easier refining of the biokraft pulps seems to be a consequence of less resistant fiber walls. Improved beatability of biopulps was tentatively related to short fibers and fines formation during refining. We suggest that to some extent polysaccharide depolymerization occurred during the biotreatment, which also resulted in diminished pulp yields in the case of glucose/CSL cultures.

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Biopulping of Eucalyptus grandis wood chips with Phanerochaete chrysosporium RP-78 was evaluated under non-aseptic conditions in laboratory and mill wood-yard. The ability of P. chrysosporium to compete with indigenous fungi present in fresh wood chips was notorious under controlled laboratory experiments. A subsequent step involved an industrial test performed with 10-ton of fresh wood chips inoculated and maintained at 37 +/- 38 degrees C for 39 days in a biopulping pilot plant. Biotreated wood chips were pulped in a chemithermomechanical pulping mill. Net energy consumption during refining was 745 kWh ton(-1) and 610 kWh ton(-1) of processed pulp for control and biotreated wood chips, respectively. Accordingly, 18.5% net energy saving could be achieved. Biopulps contained lower shive content and had improved strength properties compared to control pulps. Tensile index improved from 25 +/- 1 N m g(-1) to 33.6 +/- 0.5 N m g(-1) and delamination strength from 217 +/- 19 kPa to 295 +/- 30 kPa.

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We describe a novel method of fabricating atom chips that are well suited to the production and manipulation of atomic Bose–Einstein condensates. Our chip was created using a silver foil and simple micro-cutting techniques without the need for photolithography. It can sustain larger currents than conventional chips, and is compatible with the patterning of complex trapping potentials. A near pure Bose–Einstein condensate of 4 × 104 87Rb atoms has been created in a magnetic microtrap formed by currents through wires on the chip. We have observed the fragmentation of atom clouds in close proximity to the silver conductors. The fragmentation has different characteristic features to those seen with copper conductors.

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The demand for more pixels is beginning to be met as manufacturers increase the native resolution of projector chips. Tiling several projectors still offers a solution to augment the pixel capacity of a display. However, problems of color and illumination uniformity across projectors need to be addressed as well as the computer software required to drive such devices. We present the results obtained on a desktop-size tiled projector array of three D-ILA projectors sharing a common illumination source. A short throw lens (0.8:1) on each projector yields a 21-in. diagonal for each image tile; the composite image on a 3×1 array is 3840×1024 pixels with a resolution of about 80 dpi. The system preserves desktop resolution, is compact, and can fit in a normal room or laboratory. The projectors are mounted on precision six-axis positioners, which allow pixel level alignment. A fiber optic beamsplitting system and a single set of red, green, and blue dichroic filters are the key to color and illumination uniformity. The D-ILA chips inside each projector can be adjusted separately to set or change characteristics such as contrast, brightness, or gamma curves. The projectors were then matched carefully: photometric variations were corrected, leading to a seamless image. Photometric measurements were performed to characterize the display and are reported here. This system is driven by a small PC cluster fitted with graphics cards and running Linux. It can be scaled to accommodate an array of 2×3 or 3×3 projectors, thus increasing the number of pixels of the final image. Finally, we present current uses of the display in fields such as astrophysics and archaeology (remote sensing).

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Obstetric complications play a role in the pathophysiology of schizophrenia. However, the biological consequences during neurodevelopment until adulthood are unknown. Microarrays have been used for expression profiling in four brain regions of a rat model of neonatal hypoxia as a common factor of obstetric complications. Animals were repeatedly exposed to chronic hypoxia from postnatal (PD) day 4 through day 8 and killed at the age of 150 days. Additional groups of rats were treated with clozapine from PD 120-150. Self-spotted chips containing 340 cDNAs related to the glutamate system (""glutamate chips"") were used. The data show differential (up and down) regulations of numerous genes in frontal (FR), temporal (TE) and parietal cortex (PAR), and in caudate putamen (CPU), but evidently many more genes are upregulated in frontal and temporal cortex, whereas in parietal cortex the majority of genes are downregulated. Because of their primary presynaptic occurrence, five differentially expressed genes (CPX1, NPY, NRXN1, SNAP-25, and STX1A) have been selected for comparisons with clozapine-treated animals by qRT-PCR. Complexin 1 is upregulated in FR and TE cortex but unchanged in PAR by hypoxic treatment. Clozapine downregulates it in FR but upregulates it in PAR cortex. Similarly, syntaxin 1A was upregulated in FR, but downregulated in TE and unchanged in PAR cortex, whereas clozapine downregulated it in FR but upregulated it in PAR cortex. Hence, hypoxia alters gene expression regionally specific, which is in agreement with reports on differentially expressed presynaptic genes in schizophrenia. Chronic clozapine treatment may contribute to normalize synaptic connectivity.

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A utilização da madeira de eucalipto na confecção de painéis MDF é recente, tornando-se necessário entender as modificações em sua estrutura anatômica durante as etapas do processo industrial, notadamente no desfibramento dos cavacos. Com esse objetivo, neste estudo foram aplicadas três condições diferenciadas de desfibramento dos cavacos, alterando-se (i) o tempo de aquecimento, (ii) as pressões de digestão e de desfibramento e (iii) a energia específica de desfibramento, sendo avaliadas as características anatômicas dos componentes celulares da madeira. O aumento da intensidade de refino dos cavacos de madeira reduziu o comprimento médio das fibras e aumentou o porcentual de fibras quebradas, corroborando as imagens de microscopia eletrônica de varredura, além da diminuição do número dos vasos e de células de parênquima. Essa condição de desfibramento mais intensa promoveu, também, um característico escurecimento da coloração da polpa composta pelos elementos celulares da madeira. A aplicação de variáveis de desfibramento mais brandas aumentou a presença de feixes de fibras e do número de vasos e de parênquima, resultando em uma polpa de coloração mais clara. As alterações das características morfológicas dos componentes celulares da madeira dos cavacos de eucalipto, após o tratamento de desfibramento, relacionaram-se com as etapas do processo operacional e com a qualidade tecnológica dos painéis de fibras MDF.

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Este trabalho teve como objetivo avaliar o crescimento de mudas de maracujazeiro- amarelo em três diferentes tamanhos de recipientes, em três condições de cultivo protegido, utilizando seis diferentes substratos. Foram empregados três ambientes de cultivo: (A1) estufa em arco, coberta de filme de polietileno de 150 μm, abertura zenital e tela termorrefletora de 50% sob o filme; (A2) viveiro agrícola de tela de monofilamento, com 50% de sombra; e (A3) viveiro agrícola de tela termorrefletora, com 50% de sombra. Foram testados três volumes (V1 = xx cm³ -sacolas de polietileno de 7,5 x 11,5 cm; V2 = xx cm33 - sacolas de polietileno 10,0 x 16,5 cm; e V3 = xx cm33 -sacolas de polietileno de 15,0 x 21,5 cm) e seis substratos (S1 = solo; S2 = Plantmax®; S3 = vermiculita; S4 = fibra de coco; S5 = fibra de coco chips; e S6 = Organosuper®, composto orgânico comercial). O delineamento experimental foi inteiramente casualizado, em esquema de parcelas subsubdivididas, em que os ambientes foram as parcelas, os recipientes de diferentes volumes as subparcelas e os substratos as subsubparcelas. Aos 50 dias após a semeadura, foram medidos a altura das plantas, o comprimento da raiz, a massa de matéria seca da parte aérea e das raízes. A partir das massas de matéria seca determinaram-se a relação massa de matéria seca de parte aérea e raiz e massa de matéria seca total. A estufa foi o melhor ambiente quando se utilizou o recipiente de XX cm33 o qual proporcionou mudas maiores, com maior biomassa seca aérea, radicular e total. A vermiculita foi o melhor substrato, porém o solo adubado é uma alternativa menos dispendiosa para a região.

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Este trabalho teve como objectivo a avaliação da actual situação da indústria corticeira, o levantamento de eventuais possibilidades de inovação e o estudo de um caso promissor. Como caso promissor, decidiu-se estudar o efeito da pirólise nos resíduos de cortiça. A análise da situação actual da indústria corticeira aponta para a procura de novos produtos no sentido de alargar o mercado e promover um melhor escoamento deste recurso natural. Apesar de todos os esforços efectuados até ao momento, verifica-se que a indústria vinícola continua a ser o principal mercado da cortiça. O avanço da tecnologia tem permitido o desenvolvimento de novos produtos, alguns ainda em fase de desenvolvimento, e aponta para um potencial de inovação a vários níveis: ao nível do processo de transformação, no sentido da sua optimização; ao nível do desenvolvimento de novos produtos dado o potencial já demonstrado pela cortiça em desenvolvimentos recentes; ao nível da valorização de resíduos como, por exemplo, a consolidação de processo de recuperação de taninos da água de cozedura, a obtenção de suberina e poliois do pó e aparas de cortiça e a pirólise das aparas e pó de cortiça. Como estudo de caso, efectuou-se o estudo do efeito da pirólise em resíduos de cortiça natural, para se poder conhecer as características dos produtos obtidos bem como as condições óptimas de operação. Neste fase inicial e optou-se por se analisar as propriedades parte sólida de modo a saber as alterações sofridas durante a pirólise e estas podem apresentar uma mais-valia para o mercado corticeiro. Para efectuar o respectivo trabalho, recorreu-se a um forno pirolítico horizontal tipo Splitz e utilizou-se cortiça natural com granulometria entre 2,88 e 4,00mm. A pirólise foi realizada entre a gama de temperaturas de 400 e 900ºC e para duas rampas de aquecimento de 5ºC/min e 10ºC/min. O estudo experimental revela que na gama de temperaturas entre os 600 e 800ºC é onde a carbonização do resíduo está completa, sendo para essa mesma gama de temperaturas que se verifica, no resíduo carbonoso, um maior teor de carbono. Relativamente às rampas de aquecimento estas não apresentam efeitos significativos nas massas e teores de carbono no resíduo carbonoso final. Verificouse também, que o teor de hidrogénio diminui com o aumento da temperatura. Conclui-se que a pirólise consegue degradar os resíduos de cortiça levando à libertação de compostos que poderão ser uma mais-valia.

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Known algorithms capable of scheduling implicit-deadline sporadic tasks over identical processors at up to 100% utilisation invariably involve numerous preemptions and migrations. To the challenge of devising a scheduling scheme with as few preemptions and migrations as possible, for a given guaranteed utilisation bound, we respond with the algorithm NPS-F. It is configurable with a parameter, trading off guaranteed schedulable utilisation (up to 100%) vs preemptions. For any possible configuration, NPS-F introduces fewer preemptions than any other known algorithm matching its utilisation bound. A clustered variant of the algorithm, for systems made of multicore chips, eliminates (costly) off-chip task migrations, by dividing processors into disjoint clusters, formed by cores on the same chip (with the cluster size being a parameter). Clusters are independently scheduled (each, using non-clustered NPS-F). The utilisation bound is only moderately affected. We also formulate an important extension (applicable to both clustered and non-clustered NPS-F) which optimises the supply of processing time to executing tasks and makes it more granular. This reduces processing capacity requirements for schedulability without increasing preemptions.

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ABSTRACTOBJECTIVE To assess inter-rater reliability, test-retest reliability, and construct validity of retail food store, open-air food market, and restaurant observation tools adapted to the Brazilian urban context.METHODS This study is part of a cross-sectional observation survey conducted in 13 districts across the city of Sao Paulo, Brazil in 2010-2011. Food store and restaurant observational tools were developed based on previously available tools, and then tested it. They included measures on the availability, variety, quality, pricing, and promotion of fruits and vegetables and ultra-processed foods. We used Kappa statistics and intra-class correlation coefficients to assess inter-rater and test-retest reliabilities in samples of 142 restaurants, 97 retail food stores (including open-air food markets), and of 62 restaurants and 45 retail food stores (including open-air food markets), respectively. Construct validity as the tool’s abilities to discriminate based on store types and different income contexts were assessed in the entire sample: 305 retail food stores, 8 fruits and vegetable markets, and 472 restaurants.RESULTS Inter-rater and test-retest reliability were generally high, with most Kappa values greater than 0.70 (range 0.49-1.00). Both tools discriminated between store types and neighborhoods with different median income. Fruits and vegetables were more likely to be found in middle to higher-income neighborhoods, while soda, fruit-flavored drink mixes, cookies, and chips were cheaper and more likely to be found in lower-income neighborhoods.CONCLUSIONS The measures were reliable and able to reveal significant differences across store types and different contexts. Although some items may require revision, results suggest that the tools may be used to reliably measure the food stores and restaurant food environment in urban settings of middle-income countries. Such studies can help .inform health promotion interventions and policies in these contexts.

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Mestrado em Engenharia Mecânica - Materiais e Tecnologias de Fabrico