51 research outputs found

    InCl 3 -Catalyzed [2+3] Cycloaddition Reaction: A Rapid Synthesis of 5-Substituted 1H-tetrazole under Microwave Irradiation

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    Abstract: A series of 5-substituted 1H-tetrazole were efficiently prepared by InCl 3 catalyzed (10 mol %) from structurally divert organic nitriles with sodium azide under the influence of microwave irradiation. The present protocol was successfully applied to the aliphatic, aryl, benzylic and heterocyclic nitriles and corresponding 5-substituted 1H-tetrazole were obtained in good to excellent yield (70-96%). This method gives remarkable advantages such as short reaction time, simple work-up procedure and economical beneficial

    Novel extractant impregnated resin for preconcentration and determination of uranium from environmental samples

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    A novel method based on impregnation of Amberlite XAD-4 with extractant isonitroso-4-methyl-2-pentanone (IMP) has been developed for U6 + extraction and determination in various samples. The prepared extractant im- pregnated resin (EIR) sorbent was characterized by the field emission scanning electron microscope. The sorbent was packed in a glass column and investigated for various parameters such as pH, eluent, sample and eluent flow rates to optimize sorption desorption conditions for U6+. U6+ is quantitatively determined at pH 4 with flow rate 2 mL/min which showed recovery of 98.9%. The sorption behaviour of U6 + by EIR was also studied using different equilibrium isotherms and kinetic models and the experimental data confirmed that it follows Freundlich iso- therm and Weber-Morris pore diffusion kinetic model. The investigation of foreign ions influence on U6+ sorp- tion showed least interference and thus, facilitated its extraction and determination in Uranmicrolite (leachate) ore tailing, synthetic mixtures and spiked water samples. The detection limit was 0.41 μg/L while the limit of quantification as 1.35 μg/L made the method quite accurate

    Effect of surgical experience and spine subspecialty on the reliability of the {AO} Spine Upper Cervical Injury Classification System

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    OBJECTIVE The objective of this paper was to determine the interobserver reliability and intraobserver reproducibility of the AO Spine Upper Cervical Injury Classification System based on surgeon experience (< 5 years, 5–10 years, 10–20 years, and > 20 years) and surgical subspecialty (orthopedic spine surgery, neurosurgery, and "other" surgery). METHODS A total of 11,601 assessments of upper cervical spine injuries were evaluated based on the AO Spine Upper Cervical Injury Classification System. Reliability and reproducibility scores were obtained twice, with a 3-week time interval. Descriptive statistics were utilized to examine the percentage of accurately classified injuries, and Pearson’s chi-square or Fisher’s exact test was used to screen for potentially relevant differences between study participants. Kappa coefficients (κ) determined the interobserver reliability and intraobserver reproducibility. RESULTS The intraobserver reproducibility was substantial for surgeon experience level (< 5 years: 0.74 vs 5–10 years: 0.69 vs 10–20 years: 0.69 vs > 20 years: 0.70) and surgical subspecialty (orthopedic spine: 0.71 vs neurosurgery: 0.69 vs other: 0.68). Furthermore, the interobserver reliability was substantial for all surgical experience groups on assessment 1 (< 5 years: 0.67 vs 5–10 years: 0.62 vs 10–20 years: 0.61 vs > 20 years: 0.62), and only surgeons with > 20 years of experience did not have substantial reliability on assessment 2 (< 5 years: 0.62 vs 5–10 years: 0.61 vs 10–20 years: 0.61 vs > 20 years: 0.59). Orthopedic spine surgeons and neurosurgeons had substantial intraobserver reproducibility on both assessment 1 (0.64 vs 0.63) and assessment 2 (0.62 vs 0.63), while other surgeons had moderate reliability on assessment 1 (0.43) and fair reliability on assessment 2 (0.36). CONCLUSIONS The international reliability and reproducibility scores for the AO Spine Upper Cervical Injury Classification System demonstrated substantial intraobserver reproducibility and interobserver reliability regardless of surgical experience and spine subspecialty. These results support the global application of this classification system

    Effects of alirocumab on types of myocardial infarction: insights from the ODYSSEY OUTCOMES trial

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    Aims  The third Universal Definition of Myocardial Infarction (MI) Task Force classified MIs into five types: Type 1, spontaneous; Type 2, related to oxygen supply/demand imbalance; Type 3, fatal without ascertainment of cardiac biomarkers; Type 4, related to percutaneous coronary intervention; and Type 5, related to coronary artery bypass surgery. Low-density lipoprotein cholesterol (LDL-C) reduction with statins and proprotein convertase subtilisin–kexin Type 9 (PCSK9) inhibitors reduces risk of MI, but less is known about effects on types of MI. ODYSSEY OUTCOMES compared the PCSK9 inhibitor alirocumab with placebo in 18 924 patients with recent acute coronary syndrome (ACS) and elevated LDL-C (≥1.8 mmol/L) despite intensive statin therapy. In a pre-specified analysis, we assessed the effects of alirocumab on types of MI. Methods and results  Median follow-up was 2.8 years. Myocardial infarction types were prospectively adjudicated and classified. Of 1860 total MIs, 1223 (65.8%) were adjudicated as Type 1, 386 (20.8%) as Type 2, and 244 (13.1%) as Type 4. Few events were Type 3 (n = 2) or Type 5 (n = 5). Alirocumab reduced first MIs [hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.77–0.95; P = 0.003], with reductions in both Type 1 (HR 0.87, 95% CI 0.77–0.99; P = 0.032) and Type 2 (0.77, 0.61–0.97; P = 0.025), but not Type 4 MI. Conclusion  After ACS, alirocumab added to intensive statin therapy favourably impacted on Type 1 and 2 MIs. The data indicate for the first time that a lipid-lowering therapy can attenuate the risk of Type 2 MI. Low-density lipoprotein cholesterol reduction below levels achievable with statins is an effective preventive strategy for both MI types.For complete list of authors see http://dx.doi.org/10.1093/eurheartj/ehz299</p

    Effect of alirocumab on mortality after acute coronary syndromes. An analysis of the ODYSSEY OUTCOMES randomized clinical trial

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    Background: Previous trials of PCSK9 (proprotein convertase subtilisin-kexin type 9) inhibitors demonstrated reductions in major adverse cardiovascular events, but not death. We assessed the effects of alirocumab on death after index acute coronary syndrome. Methods: ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) was a double-blind, randomized comparison of alirocumab or placebo in 18 924 patients who had an ACS 1 to 12 months previously and elevated atherogenic lipoproteins despite intensive statin therapy. Alirocumab dose was blindly titrated to target achieved low-density lipoprotein cholesterol (LDL-C) between 25 and 50 mg/dL. We examined the effects of treatment on all-cause death and its components, cardiovascular and noncardiovascular death, with log-rank testing. Joint semiparametric models tested associations between nonfatal cardiovascular events and cardiovascular or noncardiovascular death. Results: Median follow-up was 2.8 years. Death occurred in 334 (3.5%) and 392 (4.1%) patients, respectively, in the alirocumab and placebo groups (hazard ratio [HR], 0.85; 95% CI, 0.73 to 0.98; P=0.03, nominal P value). This resulted from nonsignificantly fewer cardiovascular (240 [2.5%] vs 271 [2.9%]; HR, 0.88; 95% CI, 0.74 to 1.05; P=0.15) and noncardiovascular (94 [1.0%] vs 121 [1.3%]; HR, 0.77; 95% CI, 0.59 to 1.01; P=0.06) deaths with alirocumab. In a prespecified analysis of 8242 patients eligible for ≥3 years follow-up, alirocumab reduced death (HR, 0.78; 95% CI, 0.65 to 0.94; P=0.01). Patients with nonfatal cardiovascular events were at increased risk for cardiovascular and noncardiovascular deaths (P<0.0001 for the associations). Alirocumab reduced total nonfatal cardiovascular events (P<0.001) and thereby may have attenuated the number of cardiovascular and noncardiovascular deaths. A post hoc analysis found that, compared to patients with lower LDL-C, patients with baseline LDL-C ≥100 mg/dL (2.59 mmol/L) had a greater absolute risk of death and a larger mortality benefit from alirocumab (HR, 0.71; 95% CI, 0.56 to 0.90; Pinteraction=0.007). In the alirocumab group, all-cause death declined wit h achieved LDL-C at 4 months of treatment, to a level of approximately 30 mg/dL (adjusted P=0.017 for linear trend). Conclusions: Alirocumab added to intensive statin therapy has the potential to reduce death after acute coronary syndrome, particularly if treatment is maintained for ≥3 years, if baseline LDL-C is ≥100 mg/dL, or if achieved LDL-C is low. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01663402

    InCl3-Catalyzed [2+3] Cycloaddition Reaction: A Rapid Synthesis of 5-Substituted 1H-tetrazole under Microwave Irradiation

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    A series of 5-substituted 1H-tetrazole were efficiently prepared by InCl3 catalyzed (10 mol %) from structurally divert organic nitriles with sodium azide under the influence of microwave irradiation. The present protocol was successfully applied to the aliphatic, aryl, benzylic and heterocyclic nitriles and corresponding 5-substituted 1H-tetrazole were obtained in good to excellent yield (70-96%). This method gives remarkable advantages such as short reaction time, simple work-up procedure and economical beneficial

    Investigations on chemically capped CdS, ZnS and ZnCdS nanoparticles

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    CdS, ZnS and ZnCdS nanoparticles of various sizes (1-10 nm) are synthesized using a wet chemical route including passivation by organic capping molecules. The particles can also be doped with transition metal ions. The optical properties of the particles are investigated using UV absorption and photoluminescence spectroscopies. High resolution photoelectron spectroscopy using variable photon energy from a synchrotron source is performed to obtain detailed information about the nanoparticle surfaces. These investigations are able to reveal the termination of the nanoparticles and the nature of bonding between the surface atoms and stabilizing organic molecules

    An Improved and Scalable Synthesis of Insensitive High Explosive 4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX)

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    4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX), a well-known nitramine category explosive, is much less sensitive to impact and friction stimuli as compared to the familiar explosives, RDX and HMX. TEX is currently produced on pilot plant scale and is being pursued as an insensitive explosive. Herein a newer, improved, efficient, and high yielding protocol is developed for the synthesis of TEX by using solid acidic silica sulfuric acid as an efficient and recyclable catalyst. Sequentially for process parameters optimization, a study was carried out with variation of catalyst loading, nitric acid, and mole ratio of reactants. The process scale-up is also achieved successfully

    Study of Microstructural Parameters of Screen Printed ZnO Thick Film Sensors

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    This paper explores the compositional, morphological and structural properties of ZnO thick films prepared by a standard screen printing method and fired between 650 oC to 900 oC for 2 hours in an air atmosphere. The material characterization was done using X-ray energy dispersive analysis (EDX), X-ray diffraction (XRD) and a scanning electron microscope (SEM). The deposited films were polycrystalline in nature having the wurtzite (hexagonal) structure with a preferred orientation along the (101) plane. The result shows that the wt. % of Zn was found to be 80.39, 82.66 and 83.47 % for firing temperatures of 700, 800 and 900 oC respectively may be due to the release of excess oxygen. The effect of the firing temperature on structural parameters such as the crystallite size, specific surface area, texture coefficient, RMSmicrostrain, dislocation density and stacking fault probability have been studied. The results indicate that grain growth can be increased by increasing the firing temperature which is responsible for decreasing the RMSmicrostrain, stacking fault probability and dislocation density in ZnO thick films. The crystallite size changes from 18.58 nm to 37.23 nm with respect to the increase in the firing temperature
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