Structural rearrangement of mesostructured silica nanoparticles incorporated with ZnO catalyst and its photoactivity: effect of alkaline aqueous electrolyte concentration

ZnO-incorporated mesostructured silica nanoparticles (MSN) catalysts (ZM) were prepared by the introduction of Zn ions into the framework of MSN via a simple electrochemical system in the presence of various concentrations of NH4OH aqueous solution. The physicochemical properties of the catalysts were studied by XRD, 29Si MAS NMR, nitrogen adsorption-desorption, FE-SEM, TEM, FTIR, and photoluminescence spectroscopy. Characterization results demonstrated that the alkaline aqueous electrolyte simply generated abundant silanol groups on the surface of the catalysts as a consequence of desilication to form the hierarchical-like structure of the MSN. Subsequent restructuring of the silica network by the creation of oxygen vacancies and formation of Si-O-Zn during the electrolysis, as well as formation of new Si-O-Si bonds during calcination seemed to be the main factors that enhanced the catalytic performance of photodecolorization of methyl orange. A ZM prepared in the presence of 1.0 M NH4OH (ZM-1.0) was determined to be the most effective catalyst. The catalyst displays a higher first-order kinetics rate of 3.87 × 10-1 h-1 than unsupported ZnO (1.13 × 10-1 h-1) that prepared under the same conditions in the absence of MSN. The experiment on effect of scavengers showed that hydroxyl radicals generated from the three main sources; reduced O2 at the conduction band, decomposed water at the valence band and irradiated H2O2 in the solution, are key factors that influenced the reaction. It is also noted that the recycled ZM-1.0 catalyst maintained its activity up to five runs without serious catalyst deactivation

The Thromboembolism and Bleeding Event in Patients Receiving Warfarin, Dabigatran, or Rivaroxaban in Nonvalvular Atrial Fibrillation

Increasing in trend of Dabigatran and Rivaroxaban usage every year in Hospital Sultanah Nur Zahirah (HSNZ) has raised concerns regarding their effectiveness and safety compared to Warfarin. Therefore, we investigated the prevalence of thromboembolism (stroke or systemic embolism) and bleeding events in patients receiving Warfarin, Dabigatran or Rivaroxaban in our setting. This retrospective cohort study involved patients with nonvalvular atrial fibrillation who were started on Warfarin, Dabigatran or Rivaroxaban from January 1, 2014 to December 31, 2018. To fulfil inclusion criteria, patients must be on treatment for at least one year and for Warfarin group, at least 65% of Time in Therapeutic Range (TTR) should be achieved. Data were collected from Warfarin registration book, drug usage record card and Hospital Information System. 142 patients (Warfarin, n=98; Dabigatran, n=30; Rivaroxaban, n=14) with mean age of 68±8.7 years old were included in the study. Majority of them were male, Malay and non-smoker with 57.0%, 97.2% and 95.8% respectively. Upon study enrolment, all patients were at moderate risk of stroke (median CHA2DS2-VASc score=3) and low risk of bleeding (median HAS-BLED score=2). One Ischemic stroke was identified in each group of Rivaroxaban 15 mg and Dabigatran 150 mg. Four bleeding events occurred in all groups except for Dabigatran group that were hematuria, gum bleeding and upper gastrointestinal bleeding. Thromboembolism and bleeding events still occur in all groups. However, the prevalence is small in our setting with the percentage of 1.4% and 2.8% respectively. The events mostly attributed by the predisposed risk factors

Physicochemical properties of palm oil and palm kernel oil blend fractions after interesterification

Abstract The objective of this study was to determine the physicochemical properties of olein and stearin fractions obtained from non-interesterified (NIE), chemically interesterified (CIE) and enzymatically interesterified (EIE) 50:50 palm oil and palm kernel oil blend. The potential applications of both olein and stearin fractions were also identified. Stearin and olein fractions were obtained through a single stage dry fractionation at 25°C. The physicochemical properties analysed include percent yield, fatty acid composition (FAC), iodine value (IV), smoke point, cloud point, slip meting point (SMP) and solid fat content. Results indicated that the percent olein yield was higher from the EIE (85%) and NIE blends (82.2%) than in CIE blend (41.8%). The EIE blend produce liquid fraction with the highest amount of unsaturated fatty acid (~50%). Hence, the olein fraction of EIE blend best met the requirement to be used as frying oil based on the highest smoke point (265.1°C) and lowest cloud point (6.2°C). On the other hand, the stearin fraction of CIE blend might be suitable to be used in margarine formulation as it has SMP close to body temperature