9 research outputs found

    Heterogeneous catalysis in esterification reactions: preparation of phenethyl acetate and cyclohexyl acetate by using a variety of solid acidic catalysts

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    Esterification is an important class of reactions in the preparation of perfumery and flavor chemicals, wherein homogeneous acid catalysts are normally used. The application of solid acidic and superacidic catalysts can prove to be very effective from the viewpoint of activity, selectivity, reusability, and economy in the manufacture of perfumery esters, and thus, this paper delineates such studies in the preparation of phenethyl acetate and cyclohexyl acetate with a variety of solid acids including a complete theoretical and experimental analysis. The list of catalysts employed for this study is Filtrol-24, Amberlyst-15, sulfated zirconia, heteropolyacids (supported on silica and carbon and also unsupported), and concentrated sulfuric acid

    Predictors of permanent pacemaker insertion after TAVR: A systematic review and updated meta-analysis

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    OBJECTIVES: The aim of this analysis was to evaluate the predictors associated with increased risk of permanent pacemaker implantation (PPMI) following transcatheter aortic valve replacement (TAVR). BACKGROUND: While TAVR has evolved as the standard of care for patients with severe aortic stenosis, conduction abnormalities leading to the need for PPMI is one of the most common postprocedural complications. METHODS: A systematic literature search was performed to identify relevant trials from inception to May 2020. Summary effects were calculated using a DerSimonian and Laird random-effects model as odds ratio with 95% confidence intervals for all the clinical endpoints. RESULTS: Thirty-seven observational studies with 71 455 patients were identified. The incidence of PPMI following TAVR was 22%. Risk was greater in men and increased with age. Patients with diabetes mellitus, presence of right bundle branch block, baseline atrioventricular conduction block, and left anterior fascicular block were noted to be at higher risk. Other significant predictors include the presence of high calcium volume in the area below the left coronary cusp and noncoronary cusp, use of self-expandable valve over balloon-expandable valve, depth of implant, valve size/annulus size, predilatation balloon valvuloplasty, and postimplant balloon dilation. CONCLUSION: Fourteen factors were found to be associated with increased risk of PPMI after TAVR, suggesting early identification of high-risk populations and targeting modifiable risk factors may aid in reducing the need for this post TAVR PPMI

    Effect of genotype guided oral P2Y12 inhibitor selection after percutaneous coronary intervention: A systematic review and meta-analysis of randomized clinical trials.

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    BACKGROUND: Clopidogrel is the most frequently used P2Y12 inhibitor as a component of the dual antiplatelet regimen in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). Prior studies have shown the variable efficacy of clopidogrel due to genotypic differences in the CYP2C19 enzyme function, which converts clopidogrel to its active metabolite. The aim of this meta-analysis is to evaluate the effectiveness of genotype testing-guided P2Y12 inhibitor prescription therapy to patients after PCI for ACS compared to non-genotype guided conventional treatment. METHODS: A comprehensive literature search was performed in PubMed, Embase, and Cochrane to identify relevant trials. Summary effects were calculated using a DerSimonian and Laird random-effects model as odds ratio with 95% confidence intervals for all the clinical endpoints. RESULTS: Seven studies with 9617 patients were included. Genotype-guided strategy arm included prasugrel or ticagrelor prescription to patients with loss of function (LOF) of CYP219 alleles (most commonly alleles being *2 and *3) and clopidogrel prescription to those without the LOF allele. The conventional arm included patients treated with clopidogrel without genotype testing. Comparison of genotype arm with conventional arm showed decreased major adverse cardiovascular events (MACE), improved cardiovascular (CV) mortality, and reduced incidence of myocardial infarction (MI) in the genotype arm, and a similar stroke incidence in the two arms. Regarding adverse events, the incidence of stent thrombosis was lower in the genotype arm than the conventional arm. CONCLUSION: Our analysis illustrates the possible advantages of genotype-guided P2Y12 inhibitor prescription strategy compared to non-genotype-guided strategy with reductions in MACE, CV mortality, MI, and stent thrombosis. This analysis can be used as a stepping stone to conducting further trials determining the efficacy of this treatment strategy in various ACS subtypes

    The ATLAS experiment at the CERN Large Hadron Collider: a description of the detector configuration for Run 3

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    Abstract The ATLAS detector is installed in its experimental cavern at Point 1 of the CERN Large Hadron Collider. During Run 2 of the LHC, a luminosity of  ℒ = 2 × 1034 cm-2 s-1 was routinely achieved at the start of fills, twice the design luminosity. For Run 3, accelerator improvements, notably luminosity levelling, allow sustained running at an instantaneous luminosity of  ℒ = 2 × 1034 cm-2 s-1, with an average of up to 60 interactions per bunch crossing. The ATLAS detector has been upgraded to recover Run 1 single-lepton trigger thresholds while operating comfortably under Run 3 sustained pileup conditions. A fourth pixel layer 3.3 cm from the beam axis was added before Run 2 to improve vertex reconstruction and b-tagging performance. New Liquid Argon Calorimeter digital trigger electronics, with corresponding upgrades to the Trigger and Data Acquisition system, take advantage of a factor of 10 finer granularity to improve triggering on electrons, photons, taus, and hadronic signatures through increased pileup rejection. The inner muon endcap wheels were replaced by New Small Wheels with Micromegas and small-strip Thin Gap Chamber detectors, providing both precision tracking and Level-1 Muon trigger functionality. Trigger coverage of the inner barrel muon layer near one endcap region was augmented with modules integrating new thin-gap resistive plate chambers and smaller-diameter drift-tube chambers. Tile Calorimeter scintillation counters were added to improve electron energy resolution and background rejection. Upgrades to Minimum Bias Trigger Scintillators and Forward Detectors improve luminosity monitoring and enable total proton-proton cross section, diffractive physics, and heavy ion measurements. These upgrades are all compatible with operation in the much harsher environment anticipated after the High-Luminosity upgrade of the LHC and are the first steps towards preparing ATLAS for the High-Luminosity upgrade of the LHC. This paper describes the Run 3 configuration of the ATLAS detector.</jats:p

    Initial invasive or conservative strategy for stable coronary disease

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    BACKGROUND Among patients with stable coronary disease and moderate or severe ischemia, whether clinical outcomes are better in those who receive an invasive intervention plus medical therapy than in those who receive medical therapy alone is uncertain. METHODS We randomly assigned 5179 patients with moderate or severe ischemia to an initial invasive strategy (angiography and revascularization when feasible) and medical therapy or to an initial conservative strategy of medical therapy alone and angiography if medical therapy failed. The primary outcome was a composite of death from cardiovascular causes, myocardial infarction, or hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest. A key secondary outcome was death from cardiovascular causes or myocardial infarction. RESULTS Over a median of 3.2 years, 318 primary outcome events occurred in the invasive-strategy group and 352 occurred in the conservative-strategy group. At 6 months, the cumulative event rate was 5.3% in the invasive-strategy group and 3.4% in the conservative-strategy group (difference, 1.9 percentage points; 95% confidence interval [CI], 0.8 to 3.0); at 5 years, the cumulative event rate was 16.4% and 18.2%, respectively (difference, 121.8 percentage points; 95% CI, 124.7 to 1.0). Results were similar with respect to the key secondary outcome. The incidence of the primary outcome was sensitive to the definition of myocardial infarction; a secondary analysis yielded more procedural myocardial infarctions of uncertain clinical importance. There were 145 deaths in the invasive-strategy group and 144 deaths in the conservative-strategy group (hazard ratio, 1.05; 95% CI, 0.83 to 1.32). CONCLUSIONS Among patients with stable coronary disease and moderate or severe ischemia, we did not find evidence that an initial invasive strategy, as compared with an initial conservative strategy, reduced the risk of ischemic cardiovascular events or death from any cause over a median of 3.2 years. The trial findings were sensitive to the definition of myocardial infarction that was used

    Health-status outcomes with invasive or conservative care in coronary disease

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    BACKGROUND In the ISCHEMIA trial, an invasive strategy with angiographic assessment and revascularization did not reduce clinical events among patients with stable ischemic heart disease and moderate or severe ischemia. A secondary objective of the trial was to assess angina-related health status among these patients. METHODS We assessed angina-related symptoms, function, and quality of life with the Seattle Angina Questionnaire (SAQ) at randomization, at months 1.5, 3, and 6, and every 6 months thereafter in participants who had been randomly assigned to an invasive treatment strategy (2295 participants) or a conservative strategy (2322). Mixed-effects cumulative probability models within a Bayesian framework were used to estimate differences between the treatment groups. The primary outcome of this health-status analysis was the SAQ summary score (scores range from 0 to 100, with higher scores indicating better health status). All analyses were performed in the overall population and according to baseline angina frequency. RESULTS At baseline, 35% of patients reported having no angina in the previous month. SAQ summary scores increased in both treatment groups, with increases at 3, 12, and 36 months that were 4.1 points (95% credible interval, 3.2 to 5.0), 4.2 points (95% credible interval, 3.3 to 5.1), and 2.9 points (95% credible interval, 2.2 to 3.7) higher with the invasive strategy than with the conservative strategy. Differences were larger among participants who had more frequent angina at baseline (8.5 vs. 0.1 points at 3 months and 5.3 vs. 1.2 points at 36 months among participants with daily or weekly angina as compared with no angina). CONCLUSIONS In the overall trial population with moderate or severe ischemia, which included 35% of participants without angina at baseline, patients randomly assigned to the invasive strategy had greater improvement in angina-related health status than those assigned to the conservative strategy. The modest mean differences favoring the invasive strategy in the overall group reflected minimal differences among asymptomatic patients and larger differences among patients who had had angina at baseline
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