12 research outputs found
Rates of coverage and determinants of complete vaccination of children in rural areas of Burkina Faso (1998-2003)
Effects of acute tryptophan depletion on executive function in healthy male volunteers
BACKGROUND: Neurocognitive impairment is frequently described in a number of psychiatric disorders and may be a direct consequence of serotonergic dysfunction. As impairments in executive functions are some of the most frequently described, the purpose of this study was to examine the performance of normal volunteers on a range of executive tasks following a transient reduction of central serotonin (5-HT) levels using the method of acute tryptophan depletion (ATD). METHODS: Fifteen healthy male subjects participated in a within-subject, double-blind, counterbalanced crossover study. ATD was induced by ingestion of a 100 g amino-acid drink. Executive function was evaluated using the Wisconsin Card Sorting Test, Stroop, Verbal Fluency and Trail Making. Visual analogue scales were administered to assess mood. RESULTS: Plasma free and total tryptophan concentrations were significantly reduced by the depleting drink (P < 0.001). ATD selectively improved motor speed/ attention on the Trails A test (P = 0.027), with no effect on subjective ratings of mood. Interaction effects between drink and the order of drink administration were observed on most neurocognitive tests. CONCLUSIONS: The improvement in simple motor speed/ attention following ATD is in keeping with the ascribed role of 5-HT in the cortex, however performance on tests of executive function is not robustly altered. The presence of interaction effects on most tasks suggests that subtle changes may occur but are masked, possibly by simple learning effects, in the context of a crossover design. This has implications for the design of future studies, particularly those examining executive functions
Safety and efficacy of a urine alkalinization protocol developed for high-dose methotrexate patients during intravenous bicarbonate shortage
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Industrial operating experience of the GTE ceramic recuperator
GTE Products Corporation, under a jointly funded program with the US Department of Energy (DOE), developed a compact ceramic high temperature recuperator that could recover heat from a relatively clean exhaust gases at temperatures up to of 2500{degree}F. The DOE program was very successful in that it allowed GTE to improve the technical and economic characteristics of the recuperator and stimulate industrial acceptance of the recuperator as an energy- saving technology. The success of the DOE Program was measured by the fact that from January 1981 to December 1984, 561 recuperators were installed by GTE on new or retrofitted furnaces. One objective of this contract was to conduct a telephone survey of the industrial plants that use the recuperator to determine their operating experience, present status, and common problems, and thus to complete the historical picture. Additionally, recuperators were returned to GTE after operating on industrial furnaces, and a post mortem'' analysis was undertaken with a goal of identifying the potential reason(s) for premature failure of the ceramic matrix. When contamination of the matrix was evident, historical data and spectrographic analysis were used to identify the type of contaminant, and its source. This effort has shown the type of degradation that occurs and has identified system design techniques that can be used to maximize the ceramic recuperator life cycle. 12 refs., 14 figs., 13 tabs