26 research outputs found

    Synthesis Of ZnO Nanomaterials, WOx Nanoparticles And WOx/ZnO Nanocomposites For Inhibition Of Bacterial Growth And Organic Dyes Removal

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    Waste water treatment using wide bandgap semiconductor particles, in particular the ZnO nanoparticles, is one of the alternative and economical approach. However, the photodegradation of organic pollutants by ZnO nanoparticles is relatively poor due to fast recombination of photogenerated electron-holes. In addition, the antibacterial activities reported from various research groups were often confusing and contradicting. The present study aimed to improve the photocatalytic performance of ZnO nanoparticles from the morphology and coupling perspectives. In this project, the ZnO submicron rods (46.19 %) demonstrated better photodegradation efficiency than ZnO nanodisks (21.47 %) after 75 minutes of ultraviolet light irradiation. The photodegradation efficiency of ZnO submicron rods was improved slightly by depositing narrow bandgap semiconductor (WOx nanoparticles). The photodegradation efficiency of WOx/ZnO nanocomposites achieved 48.38 % under UV irradiation. These nanoparticles were tested for their antibacterial activity using antibacterial susceptibility assay without and with UV light irradiation. Based on the results, both ZnO submicron rods and WOx/ZnO nanocomposites displayed better antibacterial performance against Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) than Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), the effectiveness of inhibition on bacteria by these particles were bacteria-type dependent, and only Escherichia coli was sensitive to the presence of WO3

    Annealing study of α-Fe2O3 nanoparticles steel-waste based: microstructure and magnetic behavior

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    The interest of this paper is to show the influence of annealing process on magnetic properties and microstructure of -Fe2O3 derived from steel waste product (mill scales). The mill scales flakes were wet ball milling for several hours to form a fine powder. The mill scales powder was purified by using magnetic separation to isolate the magnetic and non magnetic particles. The method was continue for Curie temperature separation technique. The purified powder was annealed at 400/450/500 and 550 °C at 6 oC/mins to form hematite, -Fe2O3. The annealed powders were milled for several hours by using mechanical alloying. Annealing at varied temperatures produced α-Fe2O3 nanopowders with average crystallite size 18.1 nm to 28.6 nm. Phase transformation occurred directly by annealing in air, conversion of FeO and Fe3O4 phase to form α-Fe2O3. The correlation between the magnetic properties and microstructure, of the sintered powders at 1200 oC enables to obtain microphase of α-Fe2O3 and Fe3O4 with different particle size and magnetic properties. The resultant α-Fe2O3 nanopowders are ferromagnetic with moderate coercivities

    Towards a global partnership model in interprofessional education for cross-sector problem-solving

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    Objectives A partnership model in interprofessional education (IPE) is important in promoting a sense of global citizenship while preparing students for cross-sector problem-solving. However, the literature remains scant in providing useful guidance for the development of an IPE programme co-implemented by external partners. In this pioneering study, we describe the processes of forging global partnerships in co-implementing IPE and evaluate the programme in light of the preliminary data available. Methods This study is generally quantitative. We collected data from a total of 747 health and social care students from four higher education institutions. We utilized a descriptive narrative format and a quantitative design to present our experiences of running IPE with external partners and performed independent t-tests and analysis of variance to examine pretest and posttest mean differences in students’ data. Results We identified factors in establishing a cross-institutional IPE programme. These factors include complementarity of expertise, mutual benefits, internet connectivity, interactivity of design, and time difference. We found significant pretest–posttest differences in students’ readiness for interprofessional learning (teamwork and collaboration, positive professional identity, roles, and responsibilities). We also found a significant decrease in students’ social interaction anxiety after the IPE simulation. Conclusions The narrative of our experiences described in this manuscript could be considered by higher education institutions seeking to forge meaningful external partnerships in their effort to establish interprofessional global health education

    Future of hawking in Singapore.

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    We investigate the future of an essential part of Singapore’s service economy, the food hawking industry. We will be using the survey as our primary means of answering our fundamental research question,” Is there a future for government managed hawking in Singapore?” There are 3 main parties involved in the future of hawking: government bodies, the hawkers and the consumers of hawker fare

    Isolation and Characterization of Cellulose Nanocrystals from Oil Palm Mesocarp Fiber

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    The aim was to explore the utilization of oil palm mesocarp fiber (OPMF) as a source for the production of cellulose nanocrystals (CNC). OPMF was first treated with alkali and then bleached before the production of CNC by acid hydrolysis (H2SO4). The produced materials were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), a scanning electron microscope (SEM) and a transmission electron microscope (TEM). It was proven that acid hydrolysis can increase the crystallinity of bleached OPMF and reduce the dimension of cellulose to nano scale. Changes in the peaks of the FTIR spectrum at 2852 (C-H stretching), 1732 (C=O stretching) and 1234 cm−1 (C-O stretching) indicated that the alkali treatment completely removed hemicelluloses and lignin from the fiber surface. This can be seen from the thermogram obtained from the TGA characterization. Morphological characterization clearly showed the formation of rod-shaped CNCs. The promising results prove that OPMF is a valuable source for the production of CNC

    Study protocol for a randomized controlled trial comparing the effectiveness of physical exercise and melatonin supplement on treating sleep disturbance in children with autism spectrum disorders.

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    BackgroundPrevious study showed that both melatonin supplement and physical exercise intervention could improve sleep quality in children with autism spectrum disorders (ASD) with the increase in endogenous melatonin level. However, none of the studies have directly compared the effectiveness between the two interventions on treating sleep disturbance in children with ASD. Without direct comparison, we do not know which intervention is better. Thus, we designed a study to compare which intervention is more effective to treat sleep disturbance in children with ASD and to examine whether the combination of the two could be the most efficacious. We present a protocol for conducting a randomized controlled trial to compare the effectiveness of physical exercise and melatonin supplement on treating sleep disturbance in children with ASD.Study designThe proposed study will be a four-group randomised control trial (RCT) design, with equal allocation of participants to the three intervention groups and one control group.MethodsAll eligible participants will be randomly allocated to a morning jogging group, a melatonin supplement group, a combination group and a control group. Changes in sleep quality will be monitored through actigraphic assessment and parental sleep logs. Melatonin levels represented by 6-sulfoxymelatonin will be measured from the participants' 24-h and the first morning void urinary samples. All the assessments will be carried out before the intervention (T1), in the mid of the study (5 weeks after the commencement of the study) (T2) and after the 10-week intervention (T3). Level of statistical significance will be set at 5% (i.e. p FindingsThe findings will provide evidence to determine whether physical exercise or melatonin supplement or the combination of interventions is the most effective to treat sleep disturbance in children with ASD

    Reducing Chemotherapy Waiting Times in the Ambulatory Setting of a Tertiary Cancer Centre Using a Design Thinking Approach

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    Introduction: Chemotherapy is complex. We hypothesized that a design thinking approach could redesign preparatory processes and reduce wait times. Methods: A multidisciplinary process mapping exercise was undertaken to understand the current processes, followed by proposing and testing solutions. Proposals were selected based on desirability and feasibility. These focused on starting the morning treatments on time and scheduling pre-made regimens in these slots. The primary outcome measure was the time from the appointment to starting treatment. Treatments in the post-intervention study group were compared against a historical control group. Results: The median time to start morning treatment decreased by 46%, from 83 min (with an interquartile range 50–127) in the control group to 45 min (with an interquartile range of 24–81 min) in the study group (p p p p < 0.001). Conclusion: We have shown that a data-driven, design thinking approach can improve waiting times. This can be adapted to improve other processes in an empathetic, sustainable manner

    Effects of Camphorquinone on Cytotoxicity, Cell Cycle Regulation and Prostaglandin E2 Production of Dental Pulp Cells: Role of ROS, ATM/Chk2, MEK/ERK and Hemeoxygenase-1.

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    Camphorquinone (CQ) is a popularly-used photosensitizer in composite resin restoration. In this study, the effects of CQ on cytotoxicity and inflammation-related genes and proteins expression of pulp cells were investigated. The role of reactive oxygen species (ROS), ATM/Chk2/p53 and hemeoxygenase-1 (HO-1) and MEK/ERK signaling was also evaluated. We found that ROS and free radicals may play important role in CQ toxicity. CQ (1 and 2 mM) decreased the viability of pulp cells to about 70% and 50% of control, respectively. CQ also induced G2/M cell cycle arrest and apoptosis of pulp cells. The expression of type I collagen, cdc2, cyclin B, and cdc25C was inhibited, while p21, HO-1 and cyclooxygenase-2 (COX-2) were stimulated by CQ. CQ also activated ATM, Chk2, and p53 phosphorylation and GADD45α expression. Besides, exposure to CQ increased cellular ROS level and 8-isoprostane production. CQ also stimulated COX-2 expression and PGE2 production of pulp cells. The reduction of cell viability caused by CQ can be attenuated by N-acetyl-L-cysteine (NAC), catalase and superoxide dismutase (SOD), but can be promoted by Zinc protoporphyin (ZnPP). CQ stimulated ERK1/2 phosphorylation, and U0126 prevented the CQ-induced COX-2 expression and prostaglandin E2 (PGE2) production. These results indicate that CQ may cause cytotoxicity, cell cycle arrest, apoptosis, and PGE2 production of pulp cells. These events could be due to stimulation of ROS and 8-isoprostane production, ATM/Chk2/p53 signaling, HO-1, COX-2 and p21 expression, as well as the inhibition of cdc2, cdc25C and cyclin B1. These results are important for understanding the role of ROS in pathogenesis of pulp necrosis and pulpal inflammation after clinical composite resin filling
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