815 research outputs found

    Eco-labels voor visserij en viskweek : benchmark aan de hand van FAO-richtlijnen

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    In deze nota wordt de vraag beantwoord in hoeverre de volgende eco-labels: Marine Stewardship Council (MSC), Friend of the Sea (FOS), KRAV, Naturland, SKAL en Milieukeur voldoen aan de richtlijnen van de FAO

    Performance Centered Maintenance as a Core Policy in Strategic Maintenance Control

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    Rolling stock maintenance in the Netherlands traditionally is performed on several levels of complexity and therefore on levels of non-availability and cost. The challenge in optimizing performance and cost of rolling stock maintenance is to integrate the policy on maintenance concepts, maintenance locations and maintenance intervals (what, when & where). NedTrain as a subsidiary of the Netherlands Railways is developing and implementing this improved concept of maintenance. On one hand maintenance concepts are being improved based on the philosophy of Risk Based Maintenance, with customer demands on risks regarding safety, reliability, availability and cost as a basis for maintenance renewal. On the other hand - during analysis of current maintenance concepts and risk based improvements – modularization of maintenance tasks is taken into account leading to possibilities to perform these tasks on a lower complexity level, during natural non-availability moments of train sets (off-peak hours in daytime or at night) in local depots instead of larger workshops. With this maintenance policy “Performance Centered Maintenance”, performance improvements and cost reduction are being achieved. New strategies arise for investments in depots, train equipment (e.g. Real Time Monitoring) and training of mechanics.In this document a general overview and first results will be given of the approach

    Huishoudelijke arbeid in de schaduw van Achterhuis

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    Reactie op het hoofdstuk over de geschiedenis van de huishoudelijke arbeid uit: "arbeid een eigenaardig medicijn" van Hans Achterhui

    Essential Role of Lung Plasmacytoid Dendritic Cells in Preventing Asthmatic Reactions to Harmless Inhaled Antigen

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    Tolerance is the usual outcome of inhalation of harmless antigen, yet T helper (Th) type 2 cell sensitization to inhaled allergens induced by dendritic cells (DCs) is common in atopic asthma. Here, we show that both myeloid (m) and plasmacytoid (p) DCs take up inhaled antigen in the lung and present it in an immunogenic or tolerogenic form to draining node T cells. Strikingly, depletion of pDCs during inhalation of normally inert antigen led to immunoglobulin E sensitization, airway eosinophilia, goblet cell hyperplasia, and Th2 cell cytokine production, cardinal features of asthma. Furthermore, adoptive transfer of pDCs before sensitization prevented disease in a mouse asthma model. On a functional level, pDCs did not induce T cell division but suppressed the generation of effector T cells induced by mDCs. These studies show that pDCs provide intrinsic protection against inflammatory responses to harmless antigen. Therapies exploiting pDC function might be clinically effective in preventing the development of asthma

    Genetic characterization of wild-type measles viruses circulating in suburban Khartoum, 1997-2000

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    Measles remains endemic in many East African countries, where it is often associated with high morbidity and mortality. We collected clinical specimens from Sudanese measles patients between July 1997 and July 2000. Sequencing of the 3' 456 nucleotides of the nucleoprotein gene from 33 measles virus (MV) isolates and 8 RNA samples extracted from clinical specimens demonstrated the presence of a single endemic MV strain with little sequence variation over time (overall nucleotide divergence of 0 to 1.3%). This was confirmed by sequencing of the complete H gene of two isolates from 1997 and two from 2000, in which the overall divergence ranged between 0 and 0.5%. Comparison with MV reference strains demonstrated that the viruses belonged to clade B, genotype B3, and were most closely related to a set of viruses recently isolated in Nigeria. Our study demonstrates a remarkable genetic stability of an endemically circulating MV strain

    Substrate-induced production and secretion of cellulases by Clostridium acetobutylicum

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    Clostridium acetobutylicum ATCC 824 is a solventogenic bacterium that grows heterotrophically on a variety of carbohydrates, including glucose, cellobiose, xylose, and lichenan, a linear polymer of beta-1,3- and beta-1,4-linked beta-D-glucose units. C. acetobutylicum does not degrade cellulose, although its genome sequence contains several cellulase-encoding genes and a complete cellulosome cluster of cellulosome genes. In the present study, we demonstrate that a low but significant level of induction of cellulase activity occurs during growth on xylose or lichenan. The celF gene, located in the cellulosome-like gene cluster and coding for a unique cellulase that belongs to glycoside hydrolase family 48, was cloned in Escherichia coli, and antibodies were raised against the overproduced CelF protein. A Western blot analysis suggested a possible catabolite repression by glucose or cellobiose and an up-regulation by lichenan or xylose of the extracellular production of CelF by C. acetobutylicum. Possible reasons for the apparent inability of C. acetobutylicum to degrade cellulose are discussed

    Serological and virological characterization of clinically diagnosed cases of measles in suburban Khartoum

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    Measles continues to be a major childhood disease in terms of global morbidity and mortality. In the main areas of its endemicity the only available means of diagnosis are based on clinical criteria: the presence of a maculopapular rash and fever accompanied by cough, coryza, and/or conjunctivitis. We have studied 38 clinically diagnosed cases of measles in Khartoum, Sudan, by means of serology, reverse transcriptase PCR (RT-PCR) on throat swabs and virus isolation from lymphocytes. On the basis of serology, 28 patients were diagnosed as having an acute measles virus (MV) infection, while in 10 cases the clinical symptoms proved to have other causes. It was shown that in cases with low serum immunoglobulin M (IgM) levels, an additional measurement of IgG or virus-neutralizing antibodies was necessary to discriminate between patients with an acute MV infection sampled during an early stage of the disease and patients who had experienced an MV infection in the more distant past. The serological laboratory diagnosis was validated by an MV-specific RT-PCR: for all confirmed measles cases tested a fragment of the correct size which hybridized with a third MV-specific primer could be amplified, while all serologically negative cases were also RT-PCR negative. MV could be isolated from 17 out of 23 of the serologically confirmed cases, demonstrating that virus isolation is less reliable as a diagnostic tool than serology or RT-PCR. This study stresses the urgent need for a rapid diagnostic field test for measles
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