29 research outputs found

    Methyl Bromide Adsorption on Activated Carbon to Control Emissions from Commodity Fumigations

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    Abstract A process to control emissions of methyl bromide (MB) into the atmosphere following the fumigation of commodities has been developed. The process consists of adsorbing the MB in the vent-stream from a fumigation process onto activated carbon (carbon). Research was undertaken to observe the eects of (1) temperature, (2) relative humidity (r.h.), (3) the concentration of MB in the vent-stream, and (4) carbon type on the amount of MB that could be adsorbed (loaded) on the activated carbon. Temperature had the most eect on the loading, followed by r.h., for a given type of carbon. The loading decreased as temperature and r.h. increased. For a given temperature and r.h., the loading varied signi®cantly for dierent carbon types. These dierences were consistent with the type of pore structures of the carbons, which in turn is determined by the raw materials and by the activation procedures used during the carbon manufacturing process. Temperatures in the carbon column rose in response to the adsorption of MB. By monitoring the temperatures, the adsorption zone could be followed throughout the column from the inlet at the start of an adsorption run to column exhaustion, or breakthrough at the end of the trial. Breakthrough was reached when the MB concentration in the column exhaust stream reached 500 ppm (2 mg/l) MB. Relative humidity of the vent-stream was less critical than ®rst anticipated because of the heating of the column. The temperature increase due to the heat of adsorption lowered the r.h. at the adsorption zone which led to the increased adsorption capacity normally associated with low humidities. Published by Elsevier Science Ltd

    microRNA-184 induces a commitment switch to epidermal differentiation

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    miR-184 is a highly evolutionary conserved microRNA (miRNA) from fly to human. The importance of miR-184 was underscored by the discovery that point mutations in miR-184 gene led to corneal/lens blinding disease. However, miR-184-related function in vivo remained unclear. Here, we report that the miR-184 knockout mouse model displayed increased p63 expression in line with epidermal hyperplasia, while forced expression of miR-184 by stem/progenitor cells enhanced the Notch pathway and induced epidermal hypoplasia. In line, miR-184 reduced clonogenicity and accelerated differentiation of human epidermal cells. We showed that by directly repressing cytokeratin 15 (K15) and FIH1, miR-184 induces Notch activation and epidermal differentiation. The disease-causing miR-184C57U mutant failed to repress K15 and FIH1 and to induce Notch activation, suggesting a loss-of-function mechanism. Altogether, we propose that, by targeting K15 and FIH1, miR-184 regulates the transition from proliferation to early differentiation, while mis-expression or mutation in miR-184 results in impaired homeostasis

    Examination of Late Palaeolithic archaeological sites in northern Europe for the preservation of cryptotephra layers

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    We report the first major study of cryptotephra (non-visible volcanic ash layers) on Late Palaeolithic archaeological sites in northern Europe. Examination of 34 sites dating from the Last Termination reveals seven with identifiable cryptotephra layers. Preservation is observed in minerogenic and organic deposits, although tephra is more common in organic sediments. Cryptotephra layers normally occur stratigraphically above or below the archaeology. Nearby off-site palaeoclimate archives (peat bogs and lakes <0.3 km distant) were better locations for detecting tephra. However in most cases the archaeology can only be correlated indirectly with such cryptotephras. Patterns affecting the presence/absence of cryptotephra include geographic position of sites relative to the emitting volcanic centre; the influence of past atmospherics on the quantity, direction and patterns of cryptotephra transport; the nature and timing of local site sedimentation; sampling considerations and subsequent taphonomic processes. Overall, while tephrostratigraphy has the potential to improve significantly the chronology of such sites many limiting factors currently impacts the successful application

    The RESET project: constructing a European tephra lattice for refined synchronisation of environmental and archaeological events during the last c. 100 ka

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    This paper introduces the aims and scope of the RESET project (. RESponse of humans to abrupt Environmental Transitions), a programme of research funded by the Natural Environment Research Council (UK) between 2008 and 2013; it also provides the context and rationale for papers included in a special volume of Quaternary Science Reviews that report some of the project's findings. RESET examined the chronological and correlation methods employed to establish causal links between the timing of abrupt environmental transitions (AETs) on the one hand, and of human dispersal and development on the other, with a focus on the Middle and Upper Palaeolithic periods. The period of interest is the Last Glacial cycle and the early Holocene (c. 100-8 ka), during which time a number of pronounced AETs occurred. A long-running topic of debate is the degree to which human history in Europe and the Mediterranean region during the Palaeolithic was shaped by these AETs, but this has proved difficult to assess because of poor dating control. In an attempt to move the science forward, RESET examined the potential that tephra isochrons, and in particular non-visible ash layers (cryptotephras), might offer for synchronising palaeo-records with a greater degree of finesse. New tephrostratigraphical data generated by the project augment previously-established tephra frameworks for the region, and underpin a more evolved tephra 'lattice' that links palaeo-records between Greenland, the European mainland, sub-marine sequences in the Mediterranean and North Africa. The paper also outlines the significance of other contributions to this special volume: collectively, these illustrate how the lattice was constructed, how it links with cognate tephra research in Europe and elsewhere, and how the evidence of tephra isochrons is beginning to challenge long-held views about the impacts of environmental change on humans during the Palaeolithic. © 2015 Elsevier Ltd.RESET was funded through Consortium Grants awarded by the Natural Environment Research Council, UK, to a collaborating team drawn from four institutions: Royal Holloway University of London (grant reference NE/E015905/1), the Natural History Museum, London (NE/E015913/1), Oxford University (NE/E015670/1) and the University of Southampton, including the National Oceanography Centre (NE/01531X/1). The authors also wish to record their deep gratitude to four members of the scientific community who formed a consultative advisory panel during the lifetime of the RESET project: Professor Barbara Wohlfarth (Stockholm University), Professor Jørgen Peder Steffensen (Niels Bohr Institute, Copenhagen), Dr. Martin Street (Romisch-Germanisches Zentralmuseum, Neuwied) and Professor Clive Oppenheimer (Cambridge University). They provided excellent advice at key stages of the work, which we greatly valued. We also thank Jenny Kynaston (Geography Department, Royal Holloway) for construction of several of the figures in this paper, and Debbie Barrett (Elsevier) and Colin Murray Wallace (Editor-in-Chief, QSR) for their considerable assistance in the production of this special volume.Peer Reviewe

    Kostenanalyse der stationär behandelten Clostridium difficile-assoziierten Diarrhö (CDAD)

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    Aim: Clostridium difficile -associated diarrhea (CDAD) causes heavy financial burden on healthcare systems worldwide. As with all hospital-acquired infections, prolonged hospital stays are the main cost driver. Previous cost studies only include hospital billing data and compare the length of stay in contrast to non-infected patients. To date, a survey of actual cost has not yet been conducted.Method: A retrospective analysis of data for patients with nosocomial CDAD was carried out over a 1-year period at the University Hospital of Greifswald. Based on identification of CDAD related treatment processes, cost of hygienic measures, antibiotics and laboratory as well as revenue losses due to bed blockage and increased length of stay were calculated.Results: 19 patients were included in the analysis. On average, a CDAD patient causes additional costs of Euro 5,262.96. Revenue losses due to extended length of stay take the highest proportion with Euro 2,555.59 per case, followed by loss in revenue due to bed blockage during isolation with Euro 2,413.08 per case. Overall, these opportunity costs accounted for 94.41% of total costs. In contrast, costs for hygienic measures (Euro 253.98), pharmaceuticals (Euro 22.88) and laboratory (Euro 17.44) are quite low.Conclusion: CDAD results in significant additional costs for the hospital. This survey of actual costs confirms previous study results.Zielsetzung: Die Clostridium-difficile -assoziierte Diarrhö (CDAD) bedingt hohe finanzielle Belastungen für Gesundheitssysteme weltweit. Wie bei allen nosokomial erworbenen Infektionen ist ein verlängerter Krankenhausaufenthalt der wesentliche Kostentreiber. Bisherige Kostenstudien beziehen sich nur auf Krankenhausabrechnungsdaten vor Einführung des DRG-Entgeltsystems und den Vergleich von Verweildauer zu nicht infizierten Patienten. Eine Erhebung tatsächlicher Kosten steht bislang aus. Methode: Anhand einer retrospektiven Analyse wurden Daten der Universitätsmedizin Greifswald von Patienten mit einer stationär behandelten CDAD über einen 1-Jahres-Zeitraum ausgewertet. Über eine Identifizierung von CDAD-relevanten Behandlungsprozessen wurden die Kosten von Hygienemaßnahmen, Arzneimittel und Labor sowie Erlösausfälle bedingt durch Bettensperrungen und Verweildauerverlängerungen berechnet. Ergebnisse: 19 Patienten wurden in die Analyse eingeschlossen. Im Durchschnitt fallen pro CDADPatient zusätzliche Gesamtkosten in Höhe von 5.262,96 Euro an. Erlösausfälle aufgrund der verlängerten Verweildauer stellen mit 2.555,59 Euro pro Fall den höchsten Anteil dar, gefolgt von den Erlösausfällen aufgrund von Bettensperrungen während der Isolierung mit 2.413,08 Euro pro Fall. Insgesamt ergeben diese Opportunitätskosten einen Anteil von 94,41% an den Gesamtkosten. Die Kosten für Hygienemaßnahmen (253,98 Euro), Arzneimittel (22,88 Euro) und Labor (17,44 Euro) sind dem gegenüber gering.Schlussfolgerung: Die CDAD führt zu deutlichen Mehrkosten für das Krankenhaus. Unsere Erhebung der tatsächlichen Kosten bestätigt bisherige Studienergebnisse

    A copper protein and a cytochrome bind at the same site on bacterial cytochrome c peroxidase

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    Pseudoazurin binds at a single site on cytochrome c peroxidase from Paracoccus pantotrophus with a Kd of 16.4 μM at 25 °C, pH 6.0, in an endothermic reaction that is driven by a large entropy change. Sedimentation velocity experiments confirmed the presence of a single site, although results at higher pseudoazurin concentrations are complicated by the dimerization of the protein. Microcalorimetry, ultracentrifugation, and 1H NMR spectroscopy studies in which cytochrome c550, pseudoazurin, and cytochrome c peroxidase were all present could be modeled using a competitive binding algorithm. Molecular docking simulation of the binding of pseudoazurin to the peroxidase in combination with the chemical shift perturbation pattern for pseudoazurin in the presence of the peroxidase revealed a group of solutions that were situated close to the electron-transferring heme with Cu−Fe distances of about 14 Å. This is consistent with the results of 1H NMR spectroscopy, which showed that pseudoazurin binds closely enough to the electron-transferring heme of the peroxidase to perturb its set of heme methyl resonances. We conclude that cytochrome c550 and pseudoazurin bind at the same site on the cytochrome c peroxidase and that the pair of electrons required to restore the enzyme to its active state after turnover are delivered one-by-one to the electron-transferring heme
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