1,572 research outputs found

    Electrolyte management in porous battery components. Static measurements

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    The interaction between the porous hydrogen and nickel electrodes and microporous separator with respect to electrolyte management in nickel/hydrogen cells has been investigated. The distribution of electrolyte among the components has been measured and correlated with the pore size distributions, total void volume, and resistance of a variety of electrodes and separators. Calculations are used to show the effects of systematically varying these properties

    Pore size engineering applied to the design of separators for nickel-hydrogen cells and batteries

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    Pore size engineering in starved alkaline multiplate cells involves adopting techniques to widen the volume tolerance of individual cells. Separators with appropriate pore size distributions and wettability characteristics (capillary pressure considerations) to have wider volume tolerances and an ability to resist dimensional changes in the electrodes were designed. The separators studied for potential use in nickel-hydrogen cells consist of polymeric membranes as well as inorganic microporous mats. In addition to standard measurements, the resistance and distribution of electrolyte as a function of total cell electrolyte content were determined. New composite separators consisting of fibers, particles and/or binders deposited on Zircar cloth were developed in order to engineer the proper capillary pressure characteristics in the separator. These asymmetric separators were prepared from a variety of fibers, particles and binders

    Low noise charge injection in the CCD22

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    The inclusion of a charge injection structure on a charge coupled device (CCD) allows for the mitigation of charge transfer loss which can be caused by radiation induced charge trapping defects. Any traps present in the pixels of the CCD are filled by the injected charge as it is swept through the device and consequently, the charge transfer efficiency is improved in subsequently acquired images. To date, a number of different types of CCD have been manufactured featuring a variety of charge injection techniques. The e2v Technologies CCD22, used in the EPIC MOS focal plane instruments of XMM-Newton, is one such device and is the subject of this paper. A detailed understanding of charge injection operation and the use of charge injection to mitigate charge transfer losses resulting from radiation damage to CCDs will benefit a number of space projects planned for the future, including the ESA GAIA and X-ray Evolving Universe Spectrometry (XEUS) missions.The charge injection structure and mode of operation of the CCD22 are presented, followed by a detailed analysis of the uniformity and repeatability of the charge injection amplitude across the columns of the device. The effects of proton irradiation on the charge injection characteristics are also presented, in particular the effect of radiation induced bright pixels on the injected charge level

    Irradiation of the Nasopharynx

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    Alternative Bait Marker Systems for White-Tailed Deer

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    We compared alternative bait markers for a study of free-ranging white-tailed deer (Odocoileus virginianus) based on the following criteria: 1) detectability in fecal matter; 2) incorporation into corn bait; 3) palatability; and 4) cost. We used penned sheep (Ovis aries) as an experimental model to evaluate Microtaggants, metallic flakes, plastic chips, and rare earth elements as bait markers, and molasses and soy lecithin as marker adhesives. The metallic flake­-soy lecithin combination best met our criteria. It was also successful in a field study evaluating supplemental feeding on deer behavior and activity in central Wisconsin. Metallic flakes were easily detected under field conditions, readily adhered to shelled corn bait, enabled assessment of deer activity at distinct feeding sites and could be used in studies of feeding behavior and movements of other free-ranging herbivores

    Antifungal Activity Assessment of Selected Locally Sold Over-The-Counter Azole against Candida Isolates from Hospital and Community Settings of Rivers State, Nigeria

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    There seems to be multiple factors that could affect the performance of a drug which may range widely from measurements to packaging, storage, handling and standardization. Candida species are ubiquitous in nature and are found at different parts of the body, with some present as normal flora. However, drug abuse as mostly associated with the conscious intake of drugs without the guide or prescription of a physician, poses enormous challenge to personal and public health. Hence, this study was designed for comparative analysis of the antifungal activity of over the counter azole and standardized fluconazole disc on the Candida species isolated from community and hospital settings in Rivers State. All Candida isolates were inoculated onto a Sarbouraud dextrose agar plate to obtain a pure culture and then used for normal saline microscopy, germ tube test and carbohydrate assimilation tests to confirm Candida species. Antifungal susceptibility testing using the Kirby Bauer disc diffusion method was carried out and the data generated were type-set in Microsoft Excel version 2003, and transferred into statistical package for social sciences (SPSS), IBM version 21 for statistical analysis. The study results showed 59 Candida isolates with 11.9% Candida isolated testing negative to germ tube test while 88.1% of the tested positive to germ tube test. However, distribution of germ tube positive Candida species from hospital and community settings showed that the community setting had 90.6% germ tube positive Candida isolates and 9.4% germ tube negative Candida isolates while hospital settings showed 85.2% germ tube positive isolates and 14% germ tube negative isolates. In this study, 28.6% Non-albicans Candida (NAC) were susceptible to clotrimazole, 14.3% NAC were susceptible dose dependent while 57.1% were resistant to clotrimazole. However, fluconazole recorded 0% susceptibility dose dependence by Non-albicans Candida, 42.9% susceptibility and 57.1% resistance. Similarly, 63.5%, 15.4%, and 21.2% of Candida albicans were susceptible, susceptibility dose dependent and resistant respectively to fluconazole. While, 30.8%, 34.6% and 34.6% of Candida albicans were susceptible, susceptibility dose dependent and resistant to itraconazole. In conlusion, fluconazole had the best efficacy on non-albicans Candida while clotrimazole was best for killing Candida albicans It is believed that a change in attitude from self medication is very crucial as it remains a key factor that could be responsible for increased incidence of Candida species’ resistance to azole therapy. Furthermore, change towards adherence to antifungal drug regimes when encouraged and cultivated as a positive habit for all patients, could enhance monitoring of drug efficacy and clinical/treatment outcomes

    The effect of early child care attendance on childhood asthma and wheezing: A meta-analysis.

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    ObjectiveResearch evidence offers mixed results regarding the relationship between early child care attendance and childhood asthma and wheezing. A meta-analysis was conducted to synthesize the current research evidence of the association between early child care attendance and the risk of childhood asthma and wheezing.MethodPeer reviewed studies published from 1964-January 2017 were identified in MEDLINE, CINAL, and EMBASE using MeSH headings relevant to child care and asthma. Two investigators independently reviewed the selected articles from this search. All relevant articles that met our inclusion criteria were selected for further analysis. Data were extracted from studies that had sufficient data to analyze the odds of asthma or wheezing among children who attended child care.ResultsThe meta-analysis of 32 studies found that (1) early child care attendance is protective against asthma in children 3-5 years of age but not for children with asthma 6 years of age or older. (2) Early child care attendance increases the risk of wheezing among children 2 years of age or younger, but not the risk of wheezing for children over 2 years of age.ConclusionsThis meta-analysis shows that early child care attendance is not significantly associated with the risk of asthma or wheeze in children 6 years of age or older
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