649 research outputs found

    Upgrading the beam telescopes at the DESY II Test Beam Facility

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    The DESY II Test Beam Facility is a key infrastructure for modern high energy physics detector development, providing particles with a small momentum spread in a range from 1 to 6 GeV to user groups e.g. from the LHC experiments and Belle II as well as generic detector R&D. Beam telescopes are provided in all three test beam areas as precise tracking reference without time stamping, with triggered readout and a readout time of >115 μ\mus . If the highest available rates are used, multiple particles are traversing the telescopes within one readout frame, thus creating ambiguities that cannot be resolved without additional timing layers. Several upgrades are currently investigated and tested: Firstly, a fast monolithic pixel sensor, the TelePix, to provide precise track timing and triggering on a region of interest is proposed to overcome this limitation. The TelePix is a 180 nm HV-CMOS sensor that has been developed jointly by DESY, KIT and the University of Heidelberg and designed at KIT. In this publication, the performance evaluation is presented: The difference between two amplifier designs is evaluated. A high hit detection efficiency of above 99.9 % combined with a time resolution of below 4 ns at negligible pixel noise rates is determined. Finally, the digital hit output to provide region of interest triggering is evaluated and shows a short absolute delay with respect to a traditional trigger scintillator as well as an excellent time resolution. Secondly, a fast LGAD plane has been proposed to provide a time resolution of a few 10 ps, which is foreseen to drastically improve the timing performance of the telescope. Time resolutions of below 70 ps have been determined in collaboration with the University of California, Santa Barbara

    Analysis of serum inflammatory mediators identifies unique dynamic networks associated with death and spontaneous survival in pediatric acute liver failure

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    Background: Tools to predict death or spontaneous survival are necessary to inform liver transplantation (LTx) decisions in pediatric acute liver failure (PALF), but such tools are not available. Recent data suggest that immune/inflammatory dysregulation occurs in the setting of acute liver failure. We hypothesized that specific, dynamic, and measurable patterns of immune/inflammatory dysregulation will correlate with outcomes in PALF. Methods: We assayed 26 inflammatory mediators on stored serum samples obtained from a convenience sample of 49 children in the PALF study group (PALFSG) collected within 7 days after enrollment. Outcomes were assessed within 21 days of enrollment consisting of spontaneous survivors, non-survivors, and LTx recipients. Data were subjected to statistical analysis, patient-specific Principal Component Analysis (PCA), and Dynamic Bayesian Network (DBN) inference. Findings: Raw inflammatory mediator levels assessed over time did not distinguish among PALF outcomes. However, DBN analysis did reveal distinct interferon-gamma-related networks that distinguished spontaneous survivors from those who died. The network identified in LTx patients pre-transplant was more like that seen in spontaneous survivors than in those who died, a finding supported by PCA. Interpretation: The application of DBN analysis of inflammatory mediators in this small patient sample appears to differentiate survivors from non-survivors in PALF. Patterns associated with LTx pre-transplant were more like those seen in spontaneous survivors than in those who died. DBN-based analyses might lead to a better prediction of outcome in PALF, and could also have more general utility in other complex diseases with an inflammatory etiology. Copyright: © 2013 Azhar et al

    ElectrochemicalN-demethylation of tropane alkaloids

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    A practical, efficient, and selective electrochemicalN-demethylation method of tropane alkaloids to their nortropane derivatives is described. Nortropanes, such as noratropine and norscopolamine, are important intermediates for the semi-synthesis of the medicines ipratropium or oxitropium bromide, respectively. Synthesis was performed in a simple home-made electrochemical batch cell using a porous glassy carbon electrode. The reaction proceeds at room temperature in one step in a mixture of ethanol or methanol and water. The method avoids hazardous oxidizing agents such as H(2)O(2)orm-chloroperbenzoic acid (m-CPBA), toxic solvents such as chloroform, as well as metal-based catalysts. Various key parameters were investigated in electrochemical batch or flow cells, and the optimized conditions were used in batch and flow-cells at gram scale to synthesize noratropine in high yield and purity using a convenient liquid-liquid extraction method without any need for chromatographic purification. Mechanistic studies showed that the electrochemicalN-demethylation proceeds by the formation of an iminium intermediate which is converted by water as the nucleophile. The optimized method was further applied to scopolamine, cocaine, benzatropine, homatropine and tropacocaine, showing that this is a generic way ofN-demethylating tropane alkaloids to synthesize valuable precursors for pharmaceutical products

    SNAPSHOT USA 2020: A second coordinated national camera trap survey of the United States during the COVID-19 pandemic

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    Managing wildlife populations in the face of global change requires regular data on the abundance and distribution of wild animals, but acquiring these over appropriate spatial scales in a sustainable way has proven challenging. Here we present the data from Snapshot USA 2020, a second annual national mammal survey of the USA. This project involved 152 scientists setting camera traps in a standardized protocol at 1485 locations across 103 arrays in 43 states for a total of 52,710 trap-nights of survey effort. Most (58) of these arrays were also sampled during the same months (September and October) in 2019, providing a direct comparison of animal populations in 2 years that includes data from both during and before the COVID-19 pandemic. All data were managed by the eMammal system, with all species identifications checked by at least two reviewers. In total, we recorded 117,415 detections of 78 species of wild mammals, 9236 detections of at least 43 species of birds, 15,851 detections of six domestic animals and 23,825 detections of humans or their vehicles. Spatial differences across arrays explained more variation in the relative abundance than temporal variation across years for all 38 species modeled, although there are examples of significant site-level differences among years for many species. Temporal results show how species allocate their time and can be used to study species interactions, including between humans and wildlife. These data provide a snapshot of the mammal community of the USA for 2020 and will be useful for exploring the drivers of spatial and temporal changes in relative abundance and distribution, and the impacts of species interactions on daily activity patterns. There are no copyright restrictions, and please cite this paper when using these data, or a subset of these data, for publication

    SNAPSHOT USA 2019: a coordinated national camera trap survey of the United States

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    With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the SNAPSHOT USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August-24 November of 2019). We sampled wildlife at 1,509 camera trap sites from 110 camera trap arrays covering 12 different ecoregions across four development zones. This effort resulted in 166,036 unique detections of 83 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results represent a timely and standardized camera trap survey of the United States. All of the 2019 survey data are made available herein. We are currently repeating surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at eMammal.si.edu/snapshot-usa, as will future data paper submissions. These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic landscape variables, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans. There are no copyright restrictions; please cite this paper when using the data for publication

    Cost-Effectiveness of Intermittent Preventive Treatment of Malaria in Pregnancy in Southern Mozambique

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    BACKGROUND: Malaria in pregnancy is a public health problem for endemic countries. Economic evaluations of malaria preventive strategies in pregnancy are needed to guide health policies. METHODS AND FINDINGS: This analysis was carried out in the context of a trial of malaria intermittent preventive treatment in pregnancy with sulphadoxine-pyrimethamine (IPTp-SP), where both intervention groups received an insecticide treated net through the antenatal clinic (ANC) in Mozambique. The cost-effectiveness of IPTp-SP on maternal clinical malaria and neonatal survival was estimated. Correlation and threshold analyses were undertaken to assess the main factors affecting the economic outcomes and the cut-off values beyond which the intervention is no longer cost-effective. In 2007 US,theincrementalcost−effectivenessratio(ICER)formaternalmalariawas41.46US, the incremental cost-effectiveness ratio (ICER) for maternal malaria was 41.46 US (95% CI 20.5, 96.7) per disability-adjusted life-year (DALY) averted. The ICER per DALY averted due to the reduction in neonatal mortality was 1.08 US(95 (95% CI 0.43, 3.48). The ICER including both the effect on the mother and on the newborn was 1.02 US (95% CI 0.42, 3.21) per DALY averted. Efficacy was the main factor affecting the economic evaluation of IPTp-SP. The intervention remained cost-effective with an increase in drug cost per dose up to 11 times in the case of maternal malaria and 183 times in the case of neonatal mortality. CONCLUSIONS: IPTp-SP was highly cost-effective for both prevention of maternal malaria and reduction of neonatal mortality in Mozambique. These findings are likely to hold for other settings where IPTp-SP is implemented through ANC visits. The intervention remained cost-effective even with a significant increase in drug and other intervention costs. Improvements in the protective efficacy of the intervention would increase its cost-effectiveness. Provision of IPTp with a more effective, although more expensive drug than SP may still remain a cost-effective public health measure to prevent malaria in pregnancy. TRIAL REGISTRATION: ClinicalTrials.gov NCT00209781

    Technical design of the phase I Mu3e experiment

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    The Mu3e experiment aims to find or exclude the lepton flavour violating decay μ→eee at branching fractions above 10−16. A first phase of the experiment using an existing beamline at the Paul Scherrer Institute (PSI) is designed to reach a single event sensitivity of 2⋅10−15. We present an overview of all aspects of the technical design and expected performance of the phase I Mu3e detector. The high rate of up to 108 muon decays per second and the low momenta of the decay electrons and positrons pose a unique set of challenges, which we tackle using an ultra thin tracking detector based on high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurements

    Technical design of the phase I Mu3e experiment

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    The Mu3e experiment aims to find or exclude the lepton flavour violating decay μ→eee\mu \rightarrow eee at branching fractions above 10−1610^{-16}. A first phase of the experiment using an existing beamline at the Paul Scherrer Institute (PSI) is designed to reach a single event sensitivity of 2⋅10−152\cdot 10^{-15}. We present an overview of all aspects of the technical design and expected performance of the phase~I Mu3e detector. The high rate of up to 10810^{8} muon decays per second and the low momenta of the decay electrons and positrons pose a unique set of challenges, which we tackle using an ultra thin tracking detector based on high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurements.Comment: 114 pages, 185 figures. Submitted to Nuclear Instruments and Methods A. Edited by Frank Meier Aeschbacher This version has many enhancements for better readability and more detail

    A reactivity-selectivity study of the Friedel-Crafts acetylation of 3,3′-dimethylbiphenyl and the oxidation of the acetyl derivatives

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    <p>Abstract</p> <p>Background</p> <p>Friedel-Crafts acetylation is an important route to aromatic ketones, in research laboratories and in industry. The acetyl derivatives of 3,3′-dimethylbiphenyl (3,3′-dmbp) have applications in the field of liquid crystals and polymers and may be oxidized to the dicarboxylic acids and derivatives that are of interest in cancer treatment.</p> <p>Findings</p> <p>The effect of solvent and temperature on the selectivity of monoacetylation of 3,3’-dmbp by the Perrier addition procedure was studied using stoichiometric amounts of reagents. 4-Ac-3,3′-dmbp was formed almost quantitatively in boiling 1,2-dichloroethane and this is almost twice the yield hitherto reported. Using instead a molar ratio of substrate:AcCl:AlCl<sub>3</sub> equal to 1:4:4 or 1:6:6 in boiling 1,2-dichloroethane, acetylation afforded 4,4′- and 4,6′-diacetyl-3,3′-dmbp in a total yield close to 100%. The acetyl derivatives were subsequently converted to the carboxylic acids by hypochlorite oxidation. The relative stabilities of the isomeric products and the corresponding σ-complexes were studied by DFT calculations and the data indicated that mono- and diacetylation followed different mechanisms.</p> <p>Conclusions</p> <p>Friedel-Crafts acetylation of 3,3′-dmbp using the Perrier addition procedure in boiling 1,2-dichloroethane was found to be superior to other recipes. The discrimination against the 6-acetyl derivative during monoacetylation seems to reflect a mechanism including an AcCl:AlCl<sub>3</sub> complex or larger agglomerates as the electrophile, whereas the less selective diacetylations of the deactivated 4-Ac-3,3′-dmbp are suggested to include the acetyl cation as the electrophile. The DFT data also showed that complexation of intermediates and products with AlCl<sub>3</sub> does not seem to be important in determining the mechanism.</p
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