e., selection on exposed cases) and illustrate this with an example study.
Study Design and Setting: A case-control study was used to analyze the effect of statins on major bleedings during treatment with vitamin K antagonists. A total of 110 patients who experienced such bleedings were included 18-1,018 days after the bleeding complication and matched to 220 controls.
Results: Semaxanib inhibitor A protective association of major bleeding for exposure to statins (odds ratio [OR]: 0.56; 95% confidence interval: 0.29-1.08) was
found, which did not become stronger after adjustment for confounding factors. These observations lead us to suspect survivor bias. To identify this bias, results were stratified on time between bleeding event and inclusion, and repeated for a negative control (an exposure not related to survival): blood group non-O. The ORs for exposure to statins increased gradually selleck inhibitor to 1.37 with shorter time between outcome
and inclusion, whereas ORs for the negative control remained constant, confirming our hypothesis.
Conclusion: We recommend the presented method to check for overoptimistic results, that is, survivor bias in case control studies. (C) 2014 Elsevier Inc. All rights reserved.”
“BACKGROUND: Liquid-phase catalytic hydrogenation of m-dinitrobenzene is an environmentally friendly routine for m-phenylenediamine production. The key to increasing product yield is to develop catalysts with high catalytic performance. In this work, La2O3-modified BMS-777607 manufacturer Ni/SiO2 catalysts were prepared and applied to the hydrogenation of m-dinitrobenzene to m-phenylenediamine. The effect of La2O3 loading on the properties of Ni/SiO2 was investigated. The reaction kinetic study was performed in ethanol over Ni/3%La2O3-SiO2 catalyst, in order to clarify the reaction mechanism of m-dinitrobenzene hydrogenation.
RESULTS: It was found that the activity of the silica supported nickel catalysts is obviously
influenced by La2O3 loading. Ni/3%La2O3 -SiO2 catalyst exhibits high activity owing to its well dispersed nickel species, with conversion of m-dinitrobenzene and yield of m-phenylenediamine up to 97.1% and 94%, respectively. The results also show that Ni/3%La2O3 -SiO2 catalyst can be reused at least six times without significant loss of activity.
CONCLUSION: La2O3 shows strong promotion of the effect of Ni/SiO2 catalyst for liquid-phase hydrogenation of m-dinitrobenzene. La2O3 loading can affect the properties of Ni/SiO2 catalyst. Based on the study of m-dinitrobenzene hydrogenation kinetics over Ni/3%La2O3-SiO2 catalyst, a possible reaction mechanism is proposed. (c) 2009 Society of Chemical Industry”
“Objective: To determine whether BNP or NT-proBNP levels more strongly indicate or predict cardiac diseases in patients with chronic heart failure, cerebral infarction, cerebral hemorrhage, and acute cerebral infarction complicated with heart failure.