Statistical Study of the Effects of the Composition on the Oxidation Resistance of Ni-Based Superalloys

The effects of alloying elements (Co, Cr, Mo, W, Al, Ti, and Ta) on the oxidation resistance of Ni-based superalloys are studied using the Response Surface Methodology (RSM). The statistical analysis showed that Al and Ta generally improve the oxidation resistance of the alloy, whereas Ti and Mo degrade the oxidation resistance. Co, Cr, and W did not alter oxidation rate significantly when examined by the mass gain averaged for all model alloys. However, it is remarkable that the degree of the effects of alloying elements varied with the concentration of other elements. Further, the effect of each element was sometimes found to be reversed for alloy groups specified by the concentration of another element

Meta-analysis of studies investigating one-year effectiveness of transdermal nicotine patches for smoking cessation

PURPOSE: The one-year effectiveness of transdermal nicotine patches versus placebo patches for smoking cessation based on continuous or sustained abstinence was studied. METHODS: A literature search of MEDLINE (PubMed), EMBASE, and the Cochrane Central Register of Controlled Trials up to April 2006 was conducted. Articles containing relevant keywords were reviewed by two evaluators independently. To be considered for inclusion in the meta-analysis, studies had to be randomized clinical trials with a transdermal nicotine patch group and a placebo patch group, had to include at least one year of follow-up, had to have abstinence biochemically verified, and had to include the odds ratio (OR) as an outcome measure. RESULTS: Sixteen trials met the selection criteria. The total number of subjects was 9457 (6084 in the nicotine patch group and 3373 in the placebo patch group). The pooled OR for smoking abstinence at one year for the nicotine patch group versus the placebo patch group was 1.79 (95% confidence interval [CI], 1.55-2.08). The pooled OR for one-year continuous or sustained abstinence for the nicotine patch compared with placebo, excluding four studies reporting only point-prevalence abstinence, was 1.75 (95% CI, 1.49-2.05). CONCLUSION: A meta-analysis of trials of transdermal nicotine patch therapy versus placebo for smoking cessation yielded ORs for smoking abstinence of about 1.8 at one year after the start of therapy. ORs were similar whether the endpoint was point-prevalence abstinence, continuous or sustained abstinence, or both