500 research outputs found

    Design optimization of pixel sensors using device simulations for the phase-II CMS tracker upgrade

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    In order to address the problems caused by the harsh radiation environment during the high luminosity phase of the LHC (HL-LHC), all silicon tracking detectors (pixels and strips) in the CMS experiment will undergo an upgrade. And so to develop radiation hard pixel sensors, simulations have been performed using the 2D TCAD device simulator, SILVACO, to obtain design parameters. The effect of various design parameters like pixel size, pixel depth, implant width, metal overhang, p-stop concentration, p-stop depth and bulk doping density on the leakage current and critical electric field are studied for both non-irradiated as well as irradiated pixel sensors. These 2D simulation results of planar pixels are useful for providing insight into the behaviour of non-irradiated and irradiated silicon pixel sensors and further work on 3D simulation is underway. Ā© 2015 Elsevier B.V

    Noncoronary Cardiac Abnormalities Are Associated With Coronary Artery Dilation and With Laboratory Inflammatory Markers in Acute Kawasaki Disease

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    ObjectivesWe explored the association of noncoronary cardiac abnormalities with coronary artery dilation and with laboratory inflammatory markers early after Kawasaki disease (KD) diagnosis.BackgroundLeft ventricular (LV) dysfunction, mitral regurgitation (MR), and aortic root dilation occur early after diagnosis; their associations with coronary artery dilation and inflammatory markers have not been well-described.MethodsCentrally interpreted echocardiograms were obtained at KD diagnosis and 1 and 5 weeks after diagnosis on 198 subjects in the National Institutes of Health-sponsored Pediatric Heart Network KD pulsed steroid trial. Regression models were constructed to investigate the relationships among early LV dysfunction, MR, and aortic root dilation with coronary artery dilation and laboratory inflammatory markers.ResultsAt diagnosis, LV systolic dysfunction was present in 20% of subjects and was associated with coronary artery dilation, seen in 29% (p = 0.004). Although LV dysfunction improved rapidly, LV dysfunction at diagnosis predicted greater odds of coronary artery dilation at 1 and 5 weeks after diagnosis (5-week odds ratio: 2.7, 95% confidence interval: 1.2 to 6.3). At diagnosis, MR was present in 27% of subjects and aortic root dilation was present in 8%; each was associated with larger coronary artery size at diagnosis. Left ventricular dysfunction was associated with higher erythrocyte sedimentation rate and, at diagnosis only, lower serum albumin; MR was associated with higher erythrocyte sedimentation rate and lower albumin at all times. Aortic root size had little association with inflammatory markers.ConclusionsNoncoronary cardiac abnormalities are associated with coronary artery dilation and laboratory evidence of inflammation in the first 5 weeks after KD, suggesting a shared inflammatory mechanism. (Trial of Pulse Steroid Therapy in Kawasaki Disease [A Trial Conducted by the Pediatric Heart Network]; NCT00132080

    Patient-centric trials for therapeutic development in precision oncology

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    An enhanced understanding of the molecular pathology of disease gained from genomic studies is facilitating the development of treatments that target discrete molecular subclasses of tumours. Considerable associated challenges include how to advance and implement targeted drug-development strategies. Precision medicine centres on delivering the most appropriate therapy to a patient on the basis of clinical and molecular features of their disease. The development of therapeutic agents that target molecular mechanisms is driving innovation in clinical-trial strategies. Although progress has been made, modifications to existing core paradigms in oncology drug development will be required to realize fully the promise of precision medicine

    Inflammasome sensor NLRP1 controls rat macrophage susceptibility to Toxoplasma gondii

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    Toxoplasma gondii is an intracellular parasite that infects a wide range of warm-blooded species. Rats vary in their susceptibility to this parasite. The Toxo1 locus conferring Toxoplasma resistance in rats was previously mapped to a region of chromosome 10 containing Nlrp1. This gene encodes an inflammasome sensor controlling macrophage sensitivity to anthrax lethal toxin (LT) induced rapid cell death (pyroptosis). We show here that rat strain differences in Toxoplasma infected macrophage sensitivity to pyroptosis, IL-1Ī²/IL-18 processing, and inhibition of parasite proliferation are perfectly correlated with NLRP1 sequence, while inversely correlated with sensitivity to anthrax LT-induced cell death. Using recombinant inbred rats, SNP analyses and whole transcriptome gene expression studies, we narrowed the candidate genes for control of Toxoplasma-mediated rat macrophage pyroptosis to four genes, one of which was Nlrp1. Knockdown of Nlrp1 in pyroptosis-sensitive macrophages resulted in higher parasite replication and protection from cell death. Reciprocally, overexpression of the NLRP1 variant from Toxoplasma-sensitive macrophages in pyroptosis-resistant cells led to sensitization of these resistant macrophages. Our findings reveal Toxoplasma as a novel activator of the NLRP1 inflammasome in rat macrophages

    Genetic and Functional Assessment of the Role of the rs13431652-A and rs573225-A Alleles in the G6PC2 Promoter That Are Strongly Associated With Elevated Fasting Glucose Levels

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    OBJECTIVE Genome-wide association studies have identified a single nucleotide polymorphism (SNP), rs560887, located in a G6PC2 intron that is highly correlated with variations in fasting plasma glucose (FPG). G6PC2 encodes an islet-specific glucose-6-phosphatase catalytic subunit. This study examines the contribution of two G6PC2 promoter SNPs, rs13431652 and rs573225, to the association signal. RESEARCH DESIGN AND METHODS We genotyped 9,532 normal FPG participants (FPG <6.1 mmol/l) for three G6PC2 SNPs, rs13431652 (distal promoter), rs573225 (proximal promoter), rs560887 (3rd intron). We used regression analyses adjusted for age, sex, and BMI to assess the association with FPG and haplotype analyses to assess comparative SNP contributions. Fusion gene and gel retardation analyses characterized the effect of rs13431652 and rs573225 on G6PC2 promoter activity and transcription factor binding. RESULTS Genetic analyses provide evidence for a strong contribution of the promoter SNPs to FPG variability at the G6PC2 locus (rs13431652: Ī² = 0.075, P = 3.6 Ɨ 10āˆ’35; rs573225 Ī² = 0.073 P = 3.6 Ɨ 10āˆ’34), in addition to rs560887 (Ī² = 0.071, P = 1.2 Ɨ 10āˆ’31). The rs13431652-A and rs573225-A alleles promote increased NF-Y and Foxa2 binding, respectively. The rs13431652-A allele is associated with increased FPG and elevated promoter activity, consistent with the function of G6PC2 in pancreatic islets. In contrast, the rs573225-A allele is associated with elevated FPG but reduced promoter activity. CONCLUSIONS Genetic and in situ functional data support a potential role for rs13431652, but not rs573225, as a causative SNP linking G6PC2 to variations in FPG, though a causative role for rs573225 in vivo cannot be ruled out

    Baubles, Bangles, and Biotypes: A Critical Review of the use and Abuse of the Biotype Concept

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    Pest species of insects are notoriously prone to escape the weapons deployed in management efforts against them. This is particularly true in herbivorous insects. When a previously successful tactic fails the insect population has apparently adapted to it and is often considered to be a new or distinct entity, and given the non-formal category ā€˜biotypeā€™. The entities falling under the umbrella term ā€˜biotypeā€™ are not consistent either within or between biotypes, and their underlying genetic composition and origins, while generally unknown, are likely heterogeneous within and variable between biotypes. In some cases race or species may be more appropriate referents. Some examples of applications of the concept in the context of host plant resistance are discussed. It is argued here that the term ā€˜biotypeā€™ and its applications are overly simplistic, confused, have not proved useful in current pest management, and lack predictive power for future management

    Comparative costs and activity from a sample of UK clinical trials units

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    Background: The costs of medical research are a concern. Clinical Trials Units (CTUs) need to better understand variations in the costs of their activities. Methods: Representatives of ten CTUs and two grant-awarding bodies pooled their experiences in discussions over 1.5 years. Five of the CTUs provided estimates of, and written justification for, costs associated with CTU activities required to implement an identical protocol. The protocol described a 5.5-year, nonpharmacological randomized controlled trial (RCT) conducted at 20 centres. Direct and indirect costs, the number of full time equivalents (FTEs) and the FTEs attracting overheads were compared and qualitative methods (unstructured interviews and thematic analysis) were used to interpret the results. Four members of the group (funding-body representatives or award panel members) reviewed the justification statements for transparency and information content. Separately, 163 activities common to trials were assigned to roles used by nine CTUs; the consistency of role delineation was assessed by Cohen's Īŗ. Results: Median full economic cost of CTU activities was Ā£769,637 (range: Ā£661,112 to Ā£1,383,323). Indirect costs varied considerably, accounting for between 15% and 59% (median 35%) of the full economic cost of the grant. Excluding one CTU, which used external statisticians, the total number of FTEs ranged from 2.0 to 3.0; total FTEs attracting overheads ranged from 0.3 to 2.0. Variation in directly incurred staff costs depended on whether CTUs: supported particular roles from core funding rather than grants; opted not to cost certain activities into the grant; assigned clerical or data management tasks to research or administrative staff; employed extensive on-site monitoring strategies (also the main source of variation in non-staff costs). Funders preferred written justifications of costs that described both FTEs and indicative tasks for funded roles, with itemised non-staff costs. Consistency in role delineation was fair (Īŗā€‰=ā€‰0.21-0.40) for statisticians/data managers and poor for other roles (Īŗā€‰<ā€‰0.20). Conclusions: Some variation in costs is due to factors outside the control of CTUs such as access to core funding and levels of indirect costs levied by host institutions. Research is needed on strategies to control costs appropriately, especially the implementation of risk-based monitoring strategies

    Subjective and objective binge eating in relation to eating disorder symptomatology, negative affect, and personality dimensions

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    The current study explored the clinical meaningfulness of distinguishing subjective (SBE) from objective binge eating (OBE) among individuals with threshold/subthreshold bulimia nervosa (BN). We examined relations between OBEs and SBEs and eating disorder symptoms, negative affect, and personality dimensions using both a group comparison and a continuous approach
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