256 research outputs found

    Dissimilarity Based Contrastive Divergence for Anomaly Detection

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    This paper describes training of a Re- stricted Boltzmann Machine(RBM) using dissimilarity-based contrastive divergence to obtain an anomaly detector. We go over the merits of the method over other approaches and describe the method's usefulness to ob- tain a generative model

    Studies on Fabrication and Characterization of Nanoclay Reinforced Nylon-6 composites: Enhancement of Heat distortion Temperature

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    Organically modified nanoclay (cation exchange capacity of 135 to 145 meq/100 g) was used as nanophase reinforcement for fabrication of nylon-6 nanocomposites. The thickness of clay platelets varied form 1.2 nm to 1.3 nm with 3.485 nm as d-spacing. Nylon 6/nanoclay composites were fabricated with loading of 2.5, 5.0 and 10 wt. % nanoclay via direct melt compounding technique using conventional twinscrew extruder. Processing temperature profile from hopper to header was 230-240-245-260 °C and screw speed was maintained at 180 rpm. The nylon 6/clay nanocomposites were characterized for thermal and mechanical properties. The structural properties were characterized by Differential Scanning Calorimeter (DSC) and X-ray diffraction analysis. The tensile fracture morphology was analyzed by using Scanning Electron Microscope (SEM). DSC nonisothermal curves show an increase in the crystallization temperature with increasing degree of crystallinity. The crystallization rate of the nanoclay reinforced nylon 6 composites was found to be significantly faster than that for the pristine nylon 6 and suggests that the layered silicates act as nucleating centers. XRD result shows that addition of nanoclay by this technique favors the formation of γ-crystalline phase in nylon 6/nanoclay composites. Due to this, there is substantial enhancement in the tensile strength and Izod impact strength. A variation from 700 to 971 Kg/cm2 for tensile strength and from 3.0 to 3.4 Kg.cm/cm of notch for Izod impact strength. The detailed results are presented

    Synthesis of Polycarbosilane, Polymer Impregnation Pyrolysis based C SiC Composites and Prototype Development

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    Due to some extraordinary thermo-mechanical properties, silicon carbide is considered one of the best materials used for high temperature applications in defence and aerospace. Polycarbosilane (PCS) has been widely used as SiC precursor. This paper describes the research and development work undertaken to establish the technologies for synthesis and characterisation of PCS, fabrication process and characterisation of Carbon fibre reinforced SiC matrix (C/SiC) composite laminates and shaped articles. The molecular weight and softening point of the PCS was found to be 1400-1800 Mn and 140-150 °C respectively. Flexural stress of the unidirectional (UD) C/SiC composites and bidirectional (2D) C/SiC composites was found to be 400-450 MPa and 300-350 MPa respectively. Tensile stress of the 2D C/SiC composite was found to be around 200 MPa. Coefficient of thermal expansion and thermal diffusivity of the 2D C/SiC composites at RT- 1000 °C were found to be in range of 0.3-2.2×10-6/ °C and 32-6 mm2/s respectively. The fabrication process developed for the UD and 2D C/SiC composites using the indigenous PCS has been also demonstrated to fabricate typical size divergent rocket nozzle and hot structure. Fabrication process of the SiC fibre has also been described in brief

    miRNA Profiling of Naïve, Effector and Memory CD8 T Cells

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    microRNAs have recently emerged as master regulators of gene expression during development and cell differentiation. Although profound changes in gene expression also occur during antigen-induced T cell differentiation, the role of miRNAs in the process is not known. We compared the miRNA expression profiles between antigen-specific naïve, effector and memory CD8+ T cells using 3 different methods-small RNA cloning, miRNA microarray analysis and real-time PCR. Although many miRNAs were expressed in all the T cell subsets, the frequency of 7 miRNAs (miR-16, miR-21, miR-142-3p, miR-142-5p, miR-150, miR-15b and let-7f) alone accounted for ∼60% of all miRNAs, and their expression was several fold higher than the other expressed miRNAs. Global downregulation of miRNAs (including 6/7 dominantly expressed miRNAs) was observed in effector T cells compared to naïve cells and the miRNA expression levels tended to come back up in memory T cells. However, a few miRNAs, notably miR-21 were higher in effector and memory T cells compared to naïve T cells. These results suggest that concomitant with profound changes in gene expression, miRNA profile also changes dynamically during T cell differentiation. Sequence analysis of the cloned mature miRNAs revealed an extensive degree of end polymorphism. While 3′end polymorphisms dominated, heterogeneity at both ends, resembling drosha/dicer processing shift was also seen in miR-142, suggesting a possible novel mechanism to generate new miRNA and/or to diversify miRNA target selection. Overall, our results suggest that dynamic changes in the expression of miRNAs may be important for the regulation of gene expression during antigen-induced T cell differentiation. Our study also suggests possible novel mechanisms for miRNA biogenesis and function

    How Australian general practitioners engage in discussions about alcohol with their patients: a cross-sectional study

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    Objective: This study aimed to investigate factors that inhibit and facilitate discussion about alcohol between general practitioners (GPs) and patients. Design: Data analysis from a cross-sectional survey. Setting and participants: 894 GP delegates of a national health seminar series held in five capital cities of Australia in 2014. Main outcome measures: Likelihood of routine alcohol enquiry; self-assessed confidence in assessing and managing alcohol issues in primary healthcare. Results: Most GPs (87%) reported that they were likely to routinely ask patients about their alcohol consumption and had sufficient skills to manage alcohol issues (74%). Potential barriers to enquiring about alcohol included perceptions that patients are not always honest about alcohol intake (84%) and communication difficulties (44%). ‘I usually ask about alcohol’ was ranked by 36% as the number one presentation likely to prompt alcohol discussion. Altered liver function test results followed by suspected clinical depression were most frequently ranked in the top three presentations. Suspicious or frequent injuries, frequent requests for sickness certificates and long-term unemployment were ranked in the top three presentations by 20% or less. Confidence in managing alcohol issues independently predicted likelihood to ‘routinely ask’ about alcohol consumption. Lack of time emerged as the single most important barrier to routinely asking about alcohol. Lack of time was predicted by perceptions of competing health issues in patients, fear of eliciting negative responses and lower confidence in ability to manage alcohol-related issues. Conclusions: Improving GPs' confidence and ability to identify, assess and manage at-risk drinking through relevant education may facilitate greater uptake of alcohol-related enquiries in general practice settings. Routine establishment of brief alcohol assessments might improve confidence in managing alcohol issues, reduce the time burden in risk assessment, decrease potential stigma associated with raising alcohol issues and reduce the potential for negative responses from patients

    Resultant-based methods for plane curves intersection problems

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    http://www.springeronline.com/3-540-28966-6We present an algorithm for solving polynomial equations, which uses generalized eigenvalues and eigenvectors of resultant matrices. We give special attention to the case of two bivariate polynomials and the Sylvester or Bezout resultant constructions. We propose a new method to treat multiple roots, detail its numerical aspects and describe experiments on tangential problems, which show the efficiency of the approach. An industrial application of the method is presented at the end of the paper. It consists in recovering cylinders from a large cloud of points and requires intensive resolution of polynomial equations

    Meditation Awareness Training (MAT) for Work-related Wellbeing and Job Performance: A Randomised Controlled Trial

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    Due to its potential to concurrently improve work-related wellbeing (WRW) and job performance, occupational stakeholders are becoming increasingly interested in the applications of meditation. The present study conducted the first randomized controlled trial to assess the effects of meditation on outcomes relating to both WRW and job performance. Office-based middle-hierarchy managers (n = 152) received an eight-week meditation intervention (Meditation Awareness Training; MAT) or an active control intervention. MAT participants demonstrated significant and sustainable improvements (with strong effect sizes) over control-group participants in levels of work-related stress, job satisfaction, psychological distress, and employer-rated job performance. There are a number of novel implications: (i) meditation can effectuate a perceptual shift in how employees experience their work and psychological environment and may thus constitute a cost-effective WRW intervention, (ii) meditation-based (i.e., present-moment-focussed) working styles may be more effective than goal-based (i.e., future-orientated) working styles, and (iii) meditation may reduce the separation made by employees between their own interests and those of the organizations they work for

    Ultrahigh Surface Area Three-Dimensional Porous Graphitic Carbon from Conjugated Polymeric Molecular Framework

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    Porous graphitic carbon is essential for many applications such as energy storage devices, catalysts, and sorbents. However, current graphitic carbons are limited by low conductivity, low surface area, and ineffective pore structure. Here we report a scalable synthesis of porous graphitic carbons using a conjugated polymeric molecular framework as precursor. The multivalent cross-linker and rigid conjugated framework help to maintain micro- and mesoporous structures, while promoting graphitization during carbonization and chemical activation. The above unique design results in a class of highly graphitic carbons at temperature as low as 800 ??C with record-high surface area (4073 m2 g-1), large pore volume (2.26 cm-3), and hierarchical pore architecture. Such carbons simultaneously exhibit electrical conductivity >3 times more than activated carbons, very high electrochemical activity at high mass loading, and high stability, as demonstrated by supercapacitors and lithium-sulfur batteries with excellent performance. Moreover, the synthesis can be readily tuned to make a broad range of graphitic carbons with desired structures and compositions for many applications.clos

    Neuroinflammation, Mast Cells, and Glia: Dangerous Liaisons

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    The perspective of neuroinflammation as an epiphenomenon following neuron damage is being replaced by the awareness of glia and their importance in neural functions and disorders. Systemic inflammation generates signals that communicate with the brain and leads to changes in metabolism and behavior, with microglia assuming a pro-inflammatory phenotype. Identification of potential peripheral-to-central cellular links is thus a critical step in designing effective therapeutics. Mast cells may fulfill such a role. These resident immune cells are found close to and within peripheral nerves and in brain parenchyma/meninges, where they exercise a key role in orchestrating the inflammatory process from initiation through chronic activation. Mast cells and glia engage in crosstalk that contributes to accelerate disease progression; such interactions become exaggerated with aging and increased cell sensitivity to stress. Emerging evidence for oligodendrocytes, independent of myelin and support of axonal integrity, points to their having strong immune functions, innate immune receptor expression, and production/response to chemokines and cytokines that modulate immune responses in the central nervous system while engaging in crosstalk with microglia and astrocytes. In this review, we summarize the findings related to our understanding of the biology and cellular signaling mechanisms of neuroinflammation, with emphasis on mast cell-glia interactions

    Serodiagnosis of Echinococcus spp. Infection: Explorative Selection of Diagnostic Antigens by Peptide Microarray

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    Crude or purified, somatic or metabolic extracts of native antigens are routinely used for the serodiagnosis of human helminthic infections. These antigens are often cross-reactive, i.e., recognized by sera from patients infected with heterologous helminth species. To overcome limitations in antigen production, test sensitivity and specificity, chemically synthesized peptides offer a pure and standardized alternative, provided they yield acceptable operative characteristics. Ongoing genome and proteome work create new resources for the identification of antigens. Making use of the growing amount of genomic and proteomic data available in public databases, we tested a bioinformatic procedure for the selection of potentially antigenic peptides from a collection of protein sequences including conceptually translated nucleotide sequence data of Echinococcus multilocularis and E. granulosus (Plathyhelminthes, Cestoda). The in silico selection was combined with high-throughput screening of peptides on microarray and systematic validation of reactive candidates in enzyme-linked immunosorbent assay. Our study proved the applicability of this approach for selection of peptide antigens with good diagnostic characteristics. Our results suggested the pooling of several peptides to reach a high level of sensitivity required for reliable immunodiagnosis
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