304 research outputs found
Reaction pathways involved in CH4 conversion on Pd/Al2O3 catalysts : TAP as a powerful tool for the elucidation of the effective role of the metal/support interface
Temporal Analysis of Products (TAP) investigation on Natural Gas-fueled Vehicle (NGV) catalysts provides information related to the nature of reaction steps involved over noble metals and at the metal-support interface. The determination of accurate kinetic parameters for methane adsorption from single pulse experiments and subsequent investigation of sequential surface reactions from alternative CH4/O2 pulse experiments is the first step toward the establishment of relevant structure/activity relationships which can highlight the importance of the metal/support interface on freshly-prepared and aged single palladium based catalysts
Nitrogen-doped carbon nanotube spheres as metal-free catalysts for the partial oxidation of H<sub>2</sub>S
AbstractNitrogen-doped carbon nanotubes (N-CNTs) with macroscopic shaping were synthesized by a coagulation route using alginate as a coagulating agent and the as-synthesized sample was used as metal-free catalysts in the partial oxidation of H2S into elemental sulfur. The N-CNT beads display a relatively high desulfurization activity along with a high stability as a function of time on stream. The desulfurization performance of the N-CNT beads was also measured and compared to that of the Fe2O3/SiC catalyst. The N-CNT beads display a higher desulfurization activity under the similar reaction conditions with, however, lower sulfur selectivity due to the problem of diffusion of the reactant through the bead porosity
Optimal Antithrombotic Regimens for Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention An Updated Network Meta-analysis
Importance: Antithrombotic treatment in patients with atrial fibrillation (AF) and percutaneous coronary intervention (PCI) presents a balancing act with regard to bleeding and ischemic risks. Objectives: To evaluate the safety and efficacy of 4 antithrombotic regimens by conducting an up-to-date network meta-analysis and to identify the optimal treatment for patients with AF undergoing PCI. Data Sources: Online computerized database (MEDLINE). Study Selection: Five randomized studies were included (N = 11542; WOEST, PIONEER AF-PCI, RE-DUAL PCI, AUGUSTUS, ENTRUST-AF PCI). Data Extraction and Synthesis: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used in this network meta-analysis, in which bayesian random-effects models were applied. The data were analyzed from September 9 to 29, 2019. Main Outcomes and Measures: The primary safety outcome was thrombolysis in myocardial infarction (TIMI) major bleeding and the primary efficacy outcome was trial-defined major adverse cardiovascular events (MACE). Results: The total number of participants included in the study was 11 532. The mean age of the participants ranged from 70 to 72 years, 69% to 83% were male, 20% to 26% were female, and the participants were predominantly white (>90%). Compared with vitamin K antagonists (VKA) plus dual antiplatelet therapy (DAPT) (reference), the odds ratios (ORs) (95% credible intervals) for TIMI major bleeding were 0.57 (0.31-1.00) for VKA plus P2Y12 inhibitor, 0.69 (0.40-1.16) for non-VKA oral anticoagulant (NOAC) plus DAPT, and 0.52 (0.35-0.79) for NOAC plus P2Y12 inhibitor. For MACE, using VKA plus DAPT as reference, the ORs (95% credible intervals) were 0.97 (0.64-1.42) for VKA plus P2Y12 inhibitor, 0.95 (0.64-1.39) for NOAC plus DAPT, and 1.03 (0.77-1.38) for NOAC plus P2Y12 inhibitor. Conclusions and Relevance: The findings of this study suggest that an antithrombotic regimen of VKA plus DAPT should generally be avoided, because regimens in which aspirin is discontinued may lead to lower bleeding risk and no difference in antithrombotic effectiveness. The use of a NOAC plus a P2Y12 inhibitor without aspirin may be the most favorable treatment option and the preferred antithrombotic regimen for most patients with AF undergoing PCI
Fine mapping of a linkage peak with integration of lipid traits identifies novel coronary artery disease genes on chromosome 5
Coronary artery disease (CAD), and one of its intermediate risk factors, dyslipidemia, possess a demonstrable genetic component, although the genetic architecture is incompletely defined. We previously reported a linkage peak on chromosome 5q31-33 for early-onset CAD where the strength of evidence for linkage was increased in families with higher mean low density lipoprotein-cholesterol (LDL-C). Therefore, we sought to fine-map the peak using association mapping of LDL-C as an intermediate disease-related trait to further define the etiology of this linkage peak. The study populations consisted of 1908 individuals from the CATHGEN biorepository of patients undergoing cardiac catheterization; 254 families (N = 827 individuals) from the GENECARD familial study of early-onset CAD; and 162 aorta samples harvested from deceased donors. Linkage disequilibrium-tagged SNPs were selected with an average of one SNP per 20 kb for 126.6-160.2 MB (region of highest linkage) and less dense spacing (one SNP per 50 kb) for the flanking regions (117.7-126.6 and 160.2-167.5 MB) and genotyped on all samples using a custom Illumina array. Association analysis of each SNP with LDL-C was performed using multivariable linear regression (CATHGEN) and the quantitative trait transmission disequilibrium test (QTDT; GENECARD). SNPs associated with the intermediate quantitative trait, LDL-C, were then assessed for association with CAD (i.e., a qualitative phenotype) using linkage and association in the presence of linkage (APL; GENECARD) and logistic regression (CATHGEN and aortas)
Gene Expression Patterns in Peripheral Blood Correlate with the Extent of Coronary Artery Disease
Systemic and local inflammation plays a prominent role in the pathogenesis of atherosclerotic coronary artery disease, but the relationship of whole blood gene expression changes with coronary disease remains unclear. We have investigated whether gene expression patterns in peripheral blood correlate with the severity of coronary disease and whether these patterns correlate with the extent of atherosclerosis in the vascular wall
Effects of the endpoint adjudication process on the results of a randomised controlled trial: The ADVANCE trial
BACKGROUND Endpoint adjudication committees (EPAC) are widely used in clinical trials. The aim of the present analysis is to assess the effects of the endpoint adjudication process on the main findings of the ADVANCE trial (Trial registration: ClinicalTrials.gov NCT00145925). METHODS AND FINDINGS The ADVANCE trial was a multicentre, 2×2 factorial randomised controlled trial of blood pressure lowering and intensive blood glucose control in 11140 patients with type 2 diabetes. Primary outcomes were major macrovascular (nonfatal myocardial infarction, nonfatal stroke and cardiovascular death) and microvascular (new or worsening nephropathy and retinopathy) events. Suspected primary outcomes were initially reported by the investigators at the 215 sites with subsequent adjudication by the EPAC. The EPAC also adjudicated upon potential events identified directly by ongoing screening of all reported events. Over a median follow-up of 5 years, the site investigators reported one or more primary outcomes among 2443 participants. After adjudication these events were confirmed for 2077 (85%) with 48 further events added through the EPAC-led database screening process. The estimated relative risk reductions (95% confidence intervals) in the primary outcome for the blood pressure lowering comparison were 8% (−1 to 15%) based on the investigator-reported events and 9% (0 to 17%) based on the EPAC-based events (P for homogeneity = 0.70). The corresponding findings for the glucose comparison were 8% (1 to 15%) and 10% (2% to 18%) (P for homogeneity = 0.60). The effect estimates were also highly comparable when studied separately for macrovascular events and microvascular events for both comparisons (all P for homogeneity>0.6). CONCLUSIONS The endpoint adjudication process had no discernible impact on the main findings in ADVANCE. These data highlight the need for careful consideration of the likely impact of an EPAC on the findings and conclusions of clinical trials prior to their establishment.Jun Hata, Hisatomi Arima, Sophia Zoungas,, Greg Fulcher, Carol Pollock, Mark Adams, John Watson, Rohina Joshi, Andre Pascal Kengne, Toshiharu Ninomiya, Craig Anderson, Mark Woodward, Anushka Patel, Giuseppe Mancia, Neil Poulter, Stephen MacMahon, John Chalmers, Bruce Neal, on behalf of the ADVANCE Collaborative Grou
Director Characteristics and Firm Performance
The traditional methodology examining optimal boards relates a simple board variable (e.g. independence or board demography) to firm performance, however, ig- noring other board characteristics. This paper investigates how the education and business experience of directors affect firm performance. The sample consists of 1,574 directorships from 224 listed firms in Switzerland. Using OLS and including control variables, the results show that graduates of minor Swiss universities are negatively related to Tobin’s Q, and industrial knowledge and Tobin’s Q are nega- tively correlated if the firm has more divisions. In addition, director fixed effects (or unobserved characteristics) are significant, but improve the explanatory power of the models only by 5 percent
Association of the PHACTR1/EDN1 genetic locus with spontaneous coronary artery dissection
Background:
Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of acute coronary syndromes (ACS) afflicting predominantly younger to middle-aged women. Observational studies have reported a high prevalence of extracoronary vascular anomalies, especially fibromuscular dysplasia (FMD) and a low prevalence of coincidental cases of atherosclerosis. PHACTR1/EDN1 is a genetic risk locus for several vascular diseases, including FMD and coronary artery disease, with the putative causal noncoding variant at the rs9349379 locus acting as a potential enhancer for the endothelin-1 (EDN1) gene.
Objectives:
This study sought to test the association between the rs9349379 genotype and SCAD.
Methods:
Results from case control studies from France, United Kingdom, United States, and Australia were analyzed to test the association with SCAD risk, including age at first event, pregnancy-associated SCAD (P-SCAD), and recurrent SCAD.
Results:
The previously reported risk allele for FMD (rs9349379-A) was associated with a higher risk of SCAD in all studies. In a meta-analysis of 1,055 SCAD patients and 7,190 controls, the odds ratio (OR) was 1.67 (95% confidence interval [CI]: 1.50 to 1.86) per copy of rs9349379-A. In a subset of 491 SCAD patients, the OR estimate was found to be higher for the association with SCAD in patients without FMD (OR: 1.89; 95% CI: 1.53 to 2.33) than in SCAD cases with FMD (OR: 1.60; 95% CI: 1.28 to 1.99). There was no effect of genotype on age at first event, P-SCAD, or recurrence.
Conclusions:
The first genetic risk factor for SCAD was identified in the largest study conducted to date for this condition. This genetic link may contribute to the clinical overlap between SCAD and FMD
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