55 research outputs found

    Influence of chemical treatment on the recycling of composites before pyrolysis

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    Recycling of carbon fibers is one of the upcoming global research topics in composite engineering. This work investigates the influence of chemical treatment on the recovery of carbon fibers from carbon fiber reinforced plastic before pyrolysis. The chemical pretreatment was achieved using a zinc chloride/ethanol solution. The pyrolysis process was conducted in a sliding furnace. The effect of such pre-treatment on thermal degradation behaviour was determined by a thermogravimetric analyser (TGA). An original sample was also investigated for benchmarking. After the thermal pyrolysis process, the fiber tensile properties were measured using a single fiber tester. The surface functional groups and graphitization degree recovered carbon fiber were characterized using X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The surface morphology of recycled carbon fibers was investigated by SEM. Pristine carbon fibers were also included in the study for benchmarking. During the pyrolysis process, the devolatilisation temperature of the pre-impregnated prepregreduced by around 40-50°C and the peak temperature was 40-50°C lower compared to that of the original prepreg. The chemical pre-treatment process reduces the pyrolysis temperature compared to the conventional pyrolysis process. After pyrolysis in nitrogen with a small amount of air, loose carbon fibers were recovered, and their surface was clean. The similar surface functional groups and the decrease of degree of graphitization were detected on the recycled carbon fiber

    Studies of Prototype CsI(Tl) Crystal Scintillators for Low-Energy Neutrino Experiments

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    Crystal scintillators provide potential merits for the pursuit of low-energy low-background experiments. A CsI(Tl) scintillating crystal detector is being constructed to study low-energy neutrino physics at a nuclear reactor, while projects are underway to adopt this technique for dark matter searches. The choice of the geometrical parameters of the crystal modules, as well as the optimization of the read-out scheme, are the results of an R&D program. Crystals with 40 cm in length were developed. The detector requirements and the achieved performance of the prototypes are presented. Future prospects for this technique are discussed.Comment: 32 pages, 14 figure

    A Caenorhabditis elegans assay of seizure-like activity optimised for identifying antiepileptic drugs and their mechanisms of action

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    BACKGROUND: Epilepsy affects around 1% of people, but existing antiepileptic drugs (AEDs) only offer symptomatic relief and are ineffective in approximately 30% of patients. Hence, new AEDs are sorely needed. However, a major bottleneck is the low-throughput nature of early-stage AED screens in conventional rodent models. This process could potentially be expedited by using simpler invertebrate systems, such as the nematode Caenorhabditis elegans. NEW METHOD: Head-bobbing convulsions were previously reported to be inducible by pentylenetetrazol (PTZ) in C. elegans with loss-of-function mutations in unc-49, which encodes a GABAA receptor. Given that epilepsy-linked mutations in human GABAA receptors are well documented, this could represent a clinically-relevant system for early-stage AED screens. However, the original agar plate-based assay is unsuited to large-scale screening and has not been validated for identifying AEDs. Therefore, we established an alternative streamlined, higher-throughput approach whereby mutants were treated with PTZ and AEDs via liquid-based incubation. RESULTS: Convulsions induced within minutes of PTZ exposure in unc-49 mutants were strongly inhibited by the established AED ethosuximide. This protective activity was independent of ethosuximide's suggested target, the T-type calcium channel, as a null mutation in the worm cca-1 ortholog did not affect ethosuximide's anticonvulsant action. COMPARISON WITH EXISTING METHOD: Our streamlined assay is AED-validated, feasible for higher throughput compound screens, and can facilitate insights into AED mechanisms of action. CONCLUSIONS: Based on an epilepsy-associated genetic background, this C. elegans unc-49 model of seizure-like activity presents an ethical, higher throughput alternative to conventional rodent seizure models for initial AED screens

    A CsI(Tl) Scintillating Crystal Detector for the Studies of Low Energy Neutrino Interactions

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    Scintillating crystal detector may offer some potential advantages in the low-energy, low-background experiments. A 500 kg CsI(Tl) detector to be placed near the core of Nuclear Power Station II in Taiwan is being constructed for the studies of electron-neutrino scatterings and other keV-MeV range neutrino interactions. The motivations of this detector approach, the physics to be addressed, the basic experimental design, and the characteristic performance of prototype modules are described. The expected background channels and their experimental handles are discussed.Comment: 34 pages, 11 figures, submitted to Nucl. Instrum. Method

    Onset of Superfluidity in 4He Films Adsorbed on Disordered Substrates

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    We have studied 4He films adsorbed in two porous glasses, aerogel and Vycor, using high precision torsional oscillator and DC calorimetry techniques. Our investigation focused on the onset of superfluidity at low temperatures as the 4He coverage is increased. Torsional oscillator measurements of the 4He-aerogel system were used to determine the superfluid density of films with transition temperatures as low as 20 mK. Heat capacity measurements of the 4He-Vycor system probed the excitation spectrum of both non-superfluid and superfluid films for temperatures down to 10 mK. Both sets of measurements suggest that the critical coverage for the onset of superfluidity corresponds to a mobility edge in the chemical potential, so that the onset transition is the bosonic analog of a superconductor-insulator transition. The superfluid density measurements, however, are not in agreement with the scaling theory of an onset transition from a gapless, Bose glass phase to a superfluid. The heat capacity measurements show that the non-superfluid phase is better characterized as an insulator with a gap.Comment: 15 pages (RevTex), 21 figures (postscript

    The PHENIX Experiment at RHIC

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    The physics emphases of the PHENIX collaboration and the design and current status of the PHENIX detector are discussed. The plan of the collaboration for making the most effective use of the available luminosity in the first years of RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program available at http://www.rhic.bnl.gov/phenix

    Driver Fusions and Their Implications in the Development and Treatment of Human Cancers.

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    Gene fusions represent an important class of somatic alterations in cancer. We systematically investigated fusions in 9,624 tumors across 33 cancer types using multiple fusion calling tools. We identified a total of 25,664 fusions, with a 63% validation rate. Integration of gene expression, copy number, and fusion annotation data revealed that fusions involving oncogenes tend to exhibit increased expression, whereas fusions involving tumor suppressors have the opposite effect. For fusions involving kinases, we found 1,275 with an intact kinase domain, the proportion of which varied significantly across cancer types. Our study suggests that fusions drive the development of 16.5% of cancer cases and function as the sole driver in more than 1% of them. Finally, we identified druggable fusions involving genes such as TMPRSS2, RET, FGFR3, ALK, and ESR1 in 6.0% of cases, and we predicted immunogenic peptides, suggesting that fusions may provide leads for targeted drug and immune therapy

    The trans-ancestral genomic architecture of glycemic traits

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    Glycemic traits are used to diagnose and monitor type 2 diabetes and cardiometabolic health. To date, most genetic studies of glycemic traits have focused on individuals of European ancestry. Here we aggregated genome-wide association studies comprising up to 281,416 individuals without diabetes (30% non-European ancestry) for whom fasting glucose, 2-h glucose after an oral glucose challenge, glycated hemoglobin and fasting insulin data were available. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; P < 5 x 10(-8)), 80% of which had no significant evidence of between-ancestry heterogeneity. Analyses restricted to individuals of European ancestry with equivalent sample size would have led to 24 fewer new loci. Compared with single-ancestry analyses, equivalent-sized trans-ancestry fine-mapping reduced the number of estimated variants in 99% credible sets by a median of 37.5%. Genomic-feature, gene-expression and gene-set analyses revealed distinct biological signatures for each trait, highlighting different underlying biological pathways. Our results increase our understanding of diabetes pathophysiology by using trans-ancestry studies for improved power and resolution.A trans-ancestry meta-analysis of GWAS of glycemic traits in up to 281,416 individuals identifies 99 novel loci, of which one quarter was found due to the multi-ancestry approach, which also improves fine-mapping of credible variant sets.Diabetes mellitus: pathophysiological changes and therap

    Modeling Microstructure and Irradiation Effects

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    The Physics of the B Factories

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