19672 research outputs found
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Polysaccharides of Pleurotus flabellatus strain Mynuk produced by submerged fermentation as a promising novel tool against adhesion and biofilm formation of foodborne pathogens
No full textFoodborne bacteria biofilms present a major concern for the food industry. Although their numerous biological activities are well established, there is little research to date on the use of polysaccharides of mushroom origin as a possible solution for preventing biofilm formation. Therefore, the aim of this study was to examine the antiadhesion and antibiofilm effects of several types of Pleurotus flabellatus strain Mynuk polysaccharide extracts (PFSMpe), produced by air-lift submerged fermentation, against American Type Culture Collection (ATCC) and clinical strains of foodborne bacteria, as well as the cytotoxicity of these extracts. PFSMpe exhibited antiadhesion activity toward clinical isolates, and the percentage of adhesion inhibition was highest for water (WE) and exopolysaccharide (EXOPE) extracts (>50%) against Enterococcus faecalis. Selected ATCC strains were more resistant than clinical strains, indicating the antiquorum sensing mechanism of PFSMpe action. Antibiofilm activity was similar to antiadhesion activity and WE showed the strongest effect, again on E. faecalis. Differences in antiadhesion and antibiofilm effects of PFSMpe may be explained by differences in chemical composition, with crude extracts showing greater efficiency due to a synergistic effect. PFSMpe did not exhibit cyctotoxic activity against normal human cell lines. Overall, the findings of this study show that PFSMpe represents a promising novel strategy against bacterial biofilms. © 2019 Elsevier Lt
Temperature-independent chirped FBG pressure transducer with high sensitivity
No full textHigh sensitivity pressure transducer is always in demand in many industrial applications. In this paper, a highly sensitive temperature discriminated pressure transducer based on the use of natural rubber diaphragm and chirped fibre Bragg grating (CFBG) is proposed and demonstrated. The sensing mechanism is based on the measurement of bandwidth change and total reflection power. Results showed that the use of rubber diaphragm enhanced the sensitivity, which was experimentally obtained at -276.7 pm/kPa. Furthermore, the pressure transducer was temperature insensitive and cost-effective due to the simple demodulation technique. © 2019 Elsevier Lt
Temperature-insensitive pressure transducer based on reflected broadened spectrum with enhanced sensitivity
No full textPasting of half the grating of an FBG sensor on a natural rubber diaphragm was used to sense the pressure measurement. The pressure-induced strain on half of the grating resulted in bandwidth broadening. From the pressure range of 0 kPa to 20 kPa, the pressure sensitivity at 15 dB bandwidth changed was obtained at 77.7 pm/kPa with 99.94% of linearity. Through total reflected power monitoring via photodetector, the pressure transducer retrieved a sensitivity of 0.1686 dB m/kPa and evaded a complex demodulation technique. As a result of the temperature-independent bandwidth change, the pressure transducer was totally temperature insensitive. © 2019 Elsevier B.V
A new image size reduction model for an efficient visual sensor network
No full textImage size reduction for energy-efficient transmission without losing quality is critical in Visual Sensor Networks (VSNs). The proposed method finds overlapping regions using camera locations, which eliminate unfocussed regions from the input images. The sharpness for the overlapped regions is estimated to find the Dominant Overlapping Region (DOR). The proposed model partitions further the DOR into sub-DORs according to capacity of the cameras. To reduce noise effects from the sub-DOR, we propose to perform a Median operation, which results in a Compressed Significant Region (CSR). For non-DOR, we obtain Sobel edges, which reduces the size of the images down to ambinary form. The CSR and Sobel edges of the non-DORs are sent by a VSN. Experimental results and a comparative study with the state-of-the-art methods shows that the proposed model outperforms the existing methods in terms of quality, energy consumption and network lifetime. © 2019 Elsevier Inc
Numerical analysis of heat transfer in human head
No full textAn investigation of heat transfer in human head is carried out by using finite element method. The head is modeled with different tissues having varying physical properties. The current work is focused to simulate the effect of various physical and geometrical parameters such as ambient temperature, heat transfer coefficient and variation in the thickness of different tissue layers of human head. The effect of presence of hair on human head is also investigated. It is found that the deep brain temperature remains almost constant whereas a small variation occurs in the other layers with respect to varying environmental and geometrical parameters. © 2019, KSME & Springer
School level resources and students’ performance in Malaysian national type Chinese schools
No full textThe Malaysian government has always prioritised investment in education by providing quality education as one of the aspirations envisioned in the Malaysian Education Blueprint. Quality education is often associated with better learning environment, adequate resources, and quality teachers. Previous studies in Malaysia were mainly focused on socio-economic factors that determine students’ performance and were consistently focused on students’ performance in national schools. This study aims to identify school level factors that determine National Type Chinese School students’ performance in UPSR examinations. This study also analyses whether there are gaps in school level resources between higher performing and lower performing Chinese schools. Questionnaires were distributed to two hundred teachers in National Type Chinese schools around the area of Kuala Lumpur and Selangor, Malaysia. Data were then analysed using inferential statistics such as multiple regression analysis and t-test. Results indicate that band of school, number of teachers, small class size, average parents’ income, fund allocated, instructional materials, science laboratory, teacher shortage and leadership are important school level factors that determine students’ performance in UPSR examinations. The findings show that teachers perceive that there are significant differences between higher performing and lower performing schools in terms of school resources such as books, internet connections, teachers’ leadership, classroom management. These findings provide insights to policy makers on the necessary policy interventions that need to be taken to ensure quality education regardless of the performance of schools. © 2019, University of Malaya. All rights reserved
Telescopic Synthesis of Azo Compounds via Stable Arenediazonium Tosylates by Using n-Butyl Nitrite as Diazotization Reagent
No full textA multi-step catalyst-free synthesis of azo compounds by using n-butyl nitrite as a diazotization reagent and p-toluene sulfonic acid as a mild acidic agent in ethanol/water mixed solvent was investigated. In the combined one-pot synthesis process, no nitrous acid was produced during the diazotization. By controlling the conditions in a continuous process, a 62–88% yield was obtained. The current method has the following advantages: reduce waste by avoiding solvent for the purification of products in the diazotization step; save energy, time, and cost; work under environmentally benign conditions, and produce a good amount of products with potential use as azo-dyes, pigments, and therapeutic agents. © 2017, © 2017 Taylor & Francis Group, LLC
Dynamic process modeling and hybrid intelligent control of ethylene copolymerization in gas phase catalytic fluidized bed reactors
No full textBACKGROUND: Polyethylene (PE) is the most extensively consumed plastic in the world, and gas phase-based processes are widely used for its production owing to their flexibility. The sole type of reactor that can produce PE in the gas phase is the fluidized bed reactor (FBR), and effective modeling and control of FBRs are of great importance for design, scale-up and simulation studies. This paper discusses these issues and suggests a novel advanced control structure for these systems. RESULTS: A unified process modeling and control approach is introduced for ethylene copolymerization in FBRs. The results show that our previously developed two-phase model is well confirmed using real industrial data and is exact enough to further develop different control strategies. It is also shown that, owing to high system nonlinearities, conventional controllers are not suitable for this system, so advanced controllers are needed. Melt flow index (MFI) and reactor temperature are chosen as vital variables, and intelligent controllers were able to sufficiently control them. Performance indicators show that advanced controllers have a superior performance in comparison with conventional controllers. CONCLUSION: Based on control performance indicators, the adaptive neuro-fuzzy inference system (ANFIS) controller for MFI control and the hybrid ANFIS–proportional-integral-differential (PID) controller for temperature control perform better regarding disturbance rejection and setpoint tracking in comparison with conventional controllers. © 2019 Society of Chemical Industry. © 2019 Society of Chemical Industr
Cost-Effectiveness of Adjuvant Trastuzumab Therapy for Early Breast Cancer in Asia: A Systematic Review
No full textObjectives: To systematically review and assess the quality of the economic evidence of adjuvant trastuzumab usage in early breast cancer in Asian countries. Methods: Literature search was performed using 6 electronic databases (PubMed, Scopus, Ovid MEDLINE, EconLit, National Health Service Economic Evaluation Database, and ISI Web of Knowledge). The final search was performed in October 2018. All potential economic studies were then checked for eligibility. The reporting and methodological qualities of each study were independently assessed by 2 authors of this review, using the Consolidated Health Economic Evaluation Reporting Standards, Drummond, and Philips checklists. To compare the different currencies used in these studies, all costs were converted into US dollars (2016). Results: A total of 6 studies were included; most of them were performed from the healthcare provider perspective. The incremental cost-effectiveness ratio for evaluation performed for a lifetime horizon were reported at 20 816 per quality-adjusted life-year in 2 studies. The model outcome was generally sensitive to the changes in trastuzumab drug acquisition cost and discount rate, as well as its clinical effectiveness. For the quality assessment, all studies fulfilled more than 50% of the requirements in the Consolidated Health Economic Evaluation Reporting Standards, Drummond, and Philips checklists. Conclusions: Adjuvant trastuzumab therapy is considered a cost-effective option for early breast cancer in Asian countries including China, Iran, Japan, Singapore, and Taiwan. All studies were generally well conducted. Economic evaluations from the societal perspective, with inclusion of indirect and informal care costs, are warranted to facilitate informed decision making among policy makers. © 2019 ISPOR—The professional society for health economics and outcomes researc
Two-Step Purification of Glycerol as a Value Added by Product From the Biodiesel Production Process
No full textFor every ton of biodiesel produced, about 100 kg of glycerol is also generated as a by-product. The traditional method of removing glycerol is mainly by gravity separation or centrifugation. This method generates crude glycerol, which may still contain impurities such as methanol, oil, soap, salt, and other organic materials at ppm levels. The effective usage of crude glycerol is important to improve the economic sustainability of the biodiesel industry while reducing the environmental impacts caused by the generated waste. The application and value of crude glycerol can be enhanced if these impurities are removed or minimized. Thus, it is important to develop a method which can increase the economic and applicable value of crude glycerol. Therefore, in the present study, the dual step purification method comprised of acidification and ion exchange techniques has been used to purify the crude glycerol and convert it into higher-value products. The acidification process started with the pH adjustment of the crude glycerol, using phosphoric acid to convert soap into fatty acid and salts. Then, the pretreated glycerol was further purified by ion exchange with a strong cation H+ resin. Gas chromatography (GC) was used to analyze both crude and purified glycerol and expressed as the weight percentage of glycerol content. A maximum glycerol purity of 98.2% was obtained after the dual step purification method at the optimized conditions of 60% of solvent, the flow rate of 15 mL/min and 40 g of resin. Further, the glycerol content measured being within the accepted amount of BS 2621:1979. Therefore, this study has proven that the proposed crude glycerol purification process is effective in improving the glycerol purity and could enhance the applicability of glycerol in producing value-added products which bring new revenue to the biodiesel industry. © Copyright © 2019 Abdul Raman, Tan and Buthiyappan