462 research outputs found

    Generation of internal stress and its effects

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    Internal stresses may be generated continually in many polycrystalline materials. Their existence is manifested by changes in crystal defect concentration and arrangement, by surface observations, by macroscopic shape changes and particularly by alteration of mechanical properties when external stresses are simultaneously imposed

    In-vitro and in-vivo evaluation of the antistaphylococcal activity of S-5556, a new 16-membered macrolide

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    During recent years, a resurgence of interest in the macrolides had led to the discovery of new derivatives of erythromycin with improved antibacterial activity and pharmacokinetic properties. In this study the in-vitro and in-vivo antistaphylococcal activity of S-5556, a 16-membered macrolide, was evaluated. In vitro, S-5556 was slightly less active than erythromycin against methicillin-susceptible Staphylococcus aureus. In contrast, it had superior activity for methicillin-resistant S. aureus (MRSA); several of these strains with inducible resistance to the macrolides-lincosamides-streptogramins group were susceptible to S-5556 whereas erythromycin was inactive. The combination of S-5556 with oxatillin was synergic for most MRSA strains tested. In vivo, a single prophylactic dose of S-5556 prevented 75%-100% of the cases of acute staphylococcal subcutaneous foreign body infection in a guinea pig-model. In a rat-model of chronic implant infection due to a methicillin- and erythromycin-resistant S. aureus strain, S-5556 significantly decreased the bacteria] concentration around the foreign material, however resistant mutants emerge

    Cypress: A High Yielding, High Quality Long-Grain Rice Variety

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    Cypress is a high-yielding, early-maturing, semidwarf, long-grain rice variety with excellent grain quality. This bulletin includes information on the history, characteristics, cultural management and pest reaction of Cypress.https://digitalcommons.lsu.edu/agcenter_bulletins/1011/thumbnail.jp

    Extensive remodeling of DC function by rapid maturation-induced transcriptional silencing.

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    The activation, or maturation, of dendritic cells (DCs) is crucial for the initiation of adaptive T-cell mediated immune responses. Research on the molecular mechanisms implicated in DC maturation has focused primarily on inducible gene-expression events promoting the acquisition of new functions, such as cytokine production and enhanced T-cell-stimulatory capacity. In contrast, mechanisms that modulate DC function by inducing widespread gene-silencing remain poorly understood. Yet the termination of key functions is known to be critical for the function of activated DCs. Genome-wide analysis of activation-induced histone deacetylation, combined with genome-wide quantification of activation-induced silencing of nascent transcription, led us to identify a novel inducible transcriptional-repression pathway that makes major contributions to the DC-maturation process. This silencing response is a rapid primary event distinct from repression mechanisms known to operate at later stages of DC maturation. The repressed genes function in pivotal processes--including antigen-presentation, extracellular signal detection, intracellular signal transduction and lipid-mediator biosynthesis--underscoring the central contribution of the silencing mechanism to rapid reshaping of DC function. Interestingly, promoters of the repressed genes exhibit a surprisingly high frequency of PU.1-occupied sites, suggesting a novel role for this lineage-specific transcription factor in marking genes poised for inducible repression

    Thin-film silicon detectors for particle detection

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    Integrated particle sensors have been developed using thin-film on ASIC technology. For this purpose, hydrogenated amorphous silicon diodes, in various configurations, have been optimized for particle detection. These devices were first deposited on glass substrates to optimize the material properties and the dark current of very thick diodes (with thickness up to 50 μm). Corresponding diodes were later directly deposited on CMOS readout chips. These integrated particle sensors have been characterized using light pulse illumination and beta particle irradiation from 63Ni and 90Sr sources. Direct detection of single low- and high-energy beta particles have been demonstrated. The application of this new integrated particle sensor concept for medical imaging is also discussed

    BMC Nephrol

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    BACKGROUND: To describe the quality of life of adolescents initiating haemodialysis, to determine the factors associated with quality of life, and to assess coping strategies and their impact on quality of life. METHODS: All adolescents initiating haemodialysis between September 2013 and July 2015 in French paediatric haemodialysis centres were included. Quality of life data were collected using the "Vecu et Sante Percue de l'Adolescent et l'Enfant" questionnaire, and coping data were collected using the Kidcope questionnaire. Adolescent's quality of life was compared with age- and sex-matched French control. RESULTS: Thirty-two adolescents were included. Their mean age was 13.9 +/- 2.0 years. The quality of life score was lowest in leisure activities and highest in relationships with medical staff. Compared with the French control, index, energy-vitality, relationships with friends, leisure activities and physical well-being scores were significantly lower in haemodialysis population. In multivariate analyses, active coping was positively associated with quality of life and especially with energy-vitality, relationships with parents and teachers, and school performance. In contrast, avoidant and negative coping were negatively associated with energy-vitality, psychological well-being and body image for avoidant coping, and body image and relationships with medical staff for negative coping. CONCLUSIONS: The quality of life of haemodialysis adolescents, and mainly the dimensions of leisure activities, physical well-being, relationships with friends and energy-vitality, were significantly altered compared to that of the French population. The impact of coping strategies on quality of life seems to be important. Given the importance of quality of life and coping strategies in adolescents with chronic disease, health care professionals should integrate these aspects into care management

    Radiation hardness of amorphous silicon particle sensors

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    Radiation tests of 32 μm thick hydrogenated amorphous silicon n-i-p diodes have been performed using a high- energy 24 GeV proton beam up to fluences of 2x1016 protons/cm2. The results are compared to irradiation of similar 1 μm and 32 μm thick n-i-p diodes using a proton beam of 405 keV at a fluence of 3x1013 protons/cm2. All samples exhibited a drop of the photoconductivity and an increase in the dark leakage current under both high and low energy proton irradiation. An almost full recovery of the device performance was observed after a subsequent thermal annealing

    Quantum efficiency measurement of n–i–p a-Si:H photodiode array on CMOS circuit for positron emission tomography (PET)

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    Detection of scintillation light from LSO (Lutetiumoxyorthosilicate) crystals used in positron emission tomography (PET) is traditionally based on photo- multipliers. The proposal is to develop a novel photo- sensor, which is based on vertically integrating an hydrogenated amorphous silicon (a-Si:H) film on a pixel readout chip. The a-Si:H film is deposited with a n-i-p diode structure. The ASIC (Application Specific Integrated Circuit) performs both signal amplification and readout processing. The advantage of such an approach is the extremely compact and low-cost design, together with ultra- low noise signal retrieval. In addition the a-Si:H offers the technological advantage of direct deposition on the wafer thanks to the low deposition temperature. The article presents the results of quantum efficiency measured on different types of a-Si:H photodiodes deposited on glass (DC measurement) and CMOS circuit (AC measurement). Quantum Efficiency (QE) up to 80% has been measured at the wavelength of interest for the optimized photodiodes. © 2007 Elsevier B.V. All rights reserved

    Combination antiretroviral therapy and the risk of myocardial infarction

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