19672 research outputs found
Sort by
Delay performance due to thermal variation on field-programmable gate array via the adoption of a stable ring oscillator
No full textThermal issues are rapidly evolving in the field-programmable gate arrays (FPGAs) and are being intensely studied as these issues appear to significantly affect the delay performance of FGPAs. A ring oscillator has been widely used as a digital temperature sensor to sense this thermal effect on FPGAs. The delay generated by the ring oscillator will vary depending on the temperature environment due to negative bias temperature instability, hot carrier injection and electromigration. It is therefore critical to adopt an accurate ring oscillator design to effectively measure the delay in FGPAs. In this study, a digital temperature sensor with a stable ring oscillator is proposed. Measurement periods of 512 and 4096 clock cycles have been implemented and the relationship between temperature, delay and total count has been established. The results show that as the temperature increases to 100°C, the delay decreases by 3.99 and 33.98% for 512 and 4096 clock cycles, respectively. It has been found that in order to reduce the degradation effect on the Virtex-6 FPGA, adopting a measurement period of 512 clock cycles is the best method. The measured data is successfully validated through a set of simulations. Thus, it may benefit a system designer and industrial player, especially in designing temperature-based FPGAs. © The Institution of Engineering and Technology 201
The comparison of the exercise stress test tolerance using Bruce and Balke-Ware protocols in Malaysians
No full textBACKGROUND: The issue of premature termination of exercise stress test in Asian people due to intolerance to rapid exercise workload increment in Bruce protocol has been pointed out. In this study, we want to compare the exercise stress test tolerance using Bruce and Balke-Ware protocols. METHODS: This was a cross-over experimental study involving 30 male subjects aged 40 to 65 performing exercise stress test using Bruce and Balke-Ware protocols. Hemodynamic responses, electrocardiographic pattern and exercise duration were monitored during the test and the reason for termination was recorded. RESULTS: Bruce protocol achieved equivalent hemodynamic responses, completion rate and test findings to Balke-Ware (P>0.001). Over 50% of the subjects were able to complete the stress test using both protocols. 46.7% (N.=14) of subjects terminate the test prematurely for Bruce and 50% (N.=15) for Balke-Ware protocol. Fatigue was the commonest cause with (57.2% N.=8, 60% N.=9), followed by achieved target heart rate (35.5% N.=5, 33.3% N.=5) and shortness of breath (7.1% N.=1, 6.7% N.=1) for Bruce and Balke-Ware respectively. The exercise capacity (metabolic equivalent) attained during exercise was similar in both protocol (P>0.001), and exercise duration in Balke-Ware was significantly longer than the Bruce protocol (P<0.001). CONCLUSIONS: We found that protocol selection does not affect the completion rate and outcome of the exercise stress test and their tolerance was similar regardless of the protocols used. For Asian peoples who were unable to complete the exercise stress test due to any reasons, their cardiac status is best evaluated using other methods. © 2018 EDIZIONI MINERVA MEDICA
Risk factors of cardiovascular disease among st-elevation myocardial infarction male patients in Malaysia from 2006 to 2013
No full textCardiovascular disease is the leading cause of death in Malaysia and globally. This study aimed to identify associated risk factors in cardiovascular disease among ST elevation myocardial infarction (STEMI) male patients and obtain a feasible model to describe the data. A total of 16,673 STEMI male patients from 18 participating hospitals across Malaysia in the National Cardiovascular Disease Database-Acute Coronary Syndrome (NCVD-ACS) registry year 2006-2013 were analysed. Univariate analysis was conducted. Significant variables from the univariate analysis were further analysed by a multivariate logistic analysis to identify the prognostic factors. The most prevalent risk factor for male patients was smoking (79.3%), followed by hypertension (54.9%) and diabetes mellitus (40.4%). At univariate level, this study is consistent with the findings from the Malaysian National Health and Morbidity Survey (NHMS) where smoking is a significant risk factor. After adjustment in multivariate logistic model, the risk factors for cardiovascular death among male patients are related to age, premorbid condition such as diabetes mellitus, hypertension, family history of CVD, Killip class, type of treatment such as percutaneous coronary intervention (PCI) and relevant comorbidity such as renal disease. Drastic efforts in the management of all risk factors in males is needed to improve adherence outcomes. © 2019, Penerbit UTM Press. All rights reserved
Autoclave-assisted synthesis of AgNPs in Z. officinale extract and assessment of their cytotoxicity, antibacterial and antioxidant activities
No full textIn this study, the authors synthesised silver nanoparticles (AgNPs) using autoclave as a simple, unique and eco-friendly approach. The effect of Zingiber officinale extract was evaluated as a reducing and stabiliser agent. According to transmission electron microscopy results, the AgNPs were in the spherical shape with a particle size of ∼17 nm. The biomedical properties of AgNPs as antibacterial agents and free radical scavenging activity were estimated. Synthesised AgNPs showed significant 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging. Strong bactericidal activity was shown by the AgNPs on Gram-positive and Gram-negative bacteria. A maximum inhibition zone of ∼14 mm was obtained for epidermidis at a concentration of 60 μg/ml for sample fabricated at 24 h. The AgNPs also showed a significant cytotoxic effect against MCF-7 breast cancer cell lines with an half maximal inhibitory concentration value of 62 μg/ml in 24 h by the MTT assay. It could be concluded that Z. officinale extract can be used effectively in the production of potential antioxidant and antimicrobial AgNPs for commercial application. © The Institution of Engineering and Technology 2018
Heterogeneous catalysis in 4-nitrophenol degradation and antioxidant activities of silver nanoparticles embedded in Tapioca starch
No full textIn this study, a simple, green and eco-friendly method was used for the synthesis of silver nanoparticles (Ag-NPs) in alkaline treated Tapioca starch. The XRD results indicated that Ag-NPs were produced after stirring for several hours at 80 °C. TEM image showed the Ag-NPs were in spherical shape with average size of 11 nm. The UV–vis results revealed clearly the formation of Ag-NPs in the range from 410 to 420 nm. Moreover, the prepared nanoparticles showed good catalytic activity in the reduction of 4-nitrophenol (4-NP). The results confirmed the catalytic activity of them in the short induction period, and the completion reaction continued within 15 min. The finding revealed also significant shift in the DPPH radical scavenging ability for studied samples. The recorded scavenging ability for the lowest concentration of the synthesized Ag-NP (50 μg/ml) was 17.29 ± 0.06 and this scavenging ability was increased to 78.60 ± 0.05, when concentration was increased to 250 μg/ml. Silver nanoparticles have many catalytic and antioxidant activities in environmental and biomedical fields. © 2016 The Author
Improvement of physicochemical properties of nanocolloidal carrier loaded with low water solubility drug for parenteral cancer treatment by Response Surface Methodology
No full textNanoemulsions have been used as a drug carrier system, particularly for poorly water-soluble drugs. Sorafenib is a poorly soluble drug and also there is no parenteral treatment. The aim of this study is the development of nanoemulsions for intravenous administration of Sorafenib. The formulations were prepared by high energy emulsification method and optimized by using Response Surface Methodology (RSM). Here, the effect of independent composition variables of lecithin (1.16–2.84%, w/w), Medium-Chain Triglycerides (2.32–5.68%, w/w) and polysorbate 80 (0.58–1.42%, w/w) amounts on the properties of Sorafenib-loaded nanoemulsion was investigated. The three responses variables were particle size, zeta potential, and polydispersity index. Optimization of the conditions according to the three dependent variables was performed for the preparation of the Sorafenib-loaded nanoemulsions with the minimum value of particle size, suitable rage of zeta potential, and polydispersity index. A formulation containing 0.05% of Sorafenib kept its properties in a satisfactory range over the evaluated period. The composition with 3% Medium-Chain Triglycerides, 2.5% lecithin and 1.22% polysorbate 80 exhibited the smallest particle size and polydispersity index (43.17 nm and 0.22, respectively) with the zeta potential of −38.8 mV was the optimized composition. The fabricated nanoemulsion was characterized by the transmission electron microscope (TEM), viscosity, and stability assessment study. Also, the cytotoxicity result showed that the optimum formulations had no significant effect on a normal cell in a low concentration of the drug but could eliminate the cancer cells. The dose-dependent toxicity made it a suitable candidate for parenteral applications in the treatment of breast cancer. Furthermore, the optimized formulation indicated good storage stability for 3 months at different temperatures (4 ± 2 °C, 25 ± 2 °C and 45 ± 2 °C)
Supplier integration roles in new product development: The automotive suppliers’ perspective
No full textThis research examined supplier integration in New Product Development (NPD) from the suppliers’ perspectives. The level of supplier involvement in NPD practices and the drivers and barriers of supplier integration in NPD were explored. In this case study based qualitative research; data were gathered from interviews conducted with ten automotive suppliers directly involved in NPD with customer firms. The suppliers to national automakers acquired higher level of integration (in terms of design responsibility, product complexity, specifications provides, influences on specifications, stage of involvement, component testing responsibility, and technological capacities) compared to the suppliers to MNC automakers. Market competition was found to be the main driver for suppliers’ involvement in NPD while limited knowledge transfer was the major barrier for suppliers’ NPD integration with customers
The effects of unsteady wind on the performances of a newly developed cross-axis wind turbine: A wind tunnel study
No full textFor the purpose of meeting the wind field in urban area, the performances of a newly invented cross-axis wind turbine (CAWT), which consists of the advantages of horizontal and vertical axis wind turbines (HAWTs and VAWTs), was examined in a calibrated open-circuit low speed wind tunnel. Firstly, to ensure the quality of the wind tunnel, the evaluations in accordance with the flow uniformity, turbulent intensity and pressure gradient along the test section were conducted within the wind tunnel, based on the IEC61400-12 standard. Furthermore, the CAWT was tested with and without the artificial turbulence generator for examining the static and dynamic performances within the steady/unsteady wind conditions at various Reynolds numbers, and the blockage inside the wind tunnel was additionally taken into account. The results showed that both the static and dynamic performances were improved with the addition of turbulence generator. Moreover, the payback period of the CAWT was calculated associated with its power performance
Encapsulation of Bacillus salmalaya 139SI using double coating biopolymer technique
No full textSustainable crop production for a rapidly growing human population is one of the current challenges faced by the agricultural sector. However, many of the chemical agents used in agriculture can be hazardous to humans, non-targeted organism and environment. Plant growth promoting rhizobacteria have demonstrated a role in promoting plant growth and health under various stress conditions including disease. Unfortunately, bacterial viability degrades due to temperature and other environmental factors (Bashan et al., Plant Soil 378: 1–33, 2014). Encapsulation of bacteria into core-shell biopolymers is one of the promising techniques to overcome the problem. This study deals with the encapsulation of Bacillus salmalaya 139SI using simple double coating biopolymer technique which consist of brown rice protein/alginate and 0·5% low molecular weight chitosan of pH 4 and 6. The influence of biopolymer to bacteria mass ratio and the chitosan pH on the encapsulation process, physic-chemical, morphology and bioactivity properties of encapsulated B. salmalaya 139SI have been studied systematically. Based on the analysis of physico-chemical, morphology and bioactivity properties, B. salmalaya 139S1 encapsulated using double coating encapsulation technology has promising viability pre- and postfreeze-drying with excellent encapsulation yields of 99·7 and 89·3% respectively. Significance and Impact of the Study: The need of a simple yet effective way of encapsulating plant growth promoting rhizobacteria is crucial to further improve their benefits to global sustainable agriculture practice. Effective encapsulation allows for protection, controlled release and function of the micro-organism, as well as providing a longer shelf life for the product. This research report offers an innovative yet simple way of encapsulating using double coating technology with environmentally friendly biopolymers that could degrade and provide nutrients when in soil. Importantly, the bioactivity of the bacteria is maintained upon encapsulation
UV- ozone treated graphene oxide/ PEDOT:PSS bilayer as a novel hole transport layer in highly efficient and stable organic solar cells
No full textThe utilization of UV-ozone (UVO) treated graphene oxide (GO)/PEDOT:PSS bilayer as hole transport layer (HTL) in solution processed organic solar cells (OSCs) is demonstrated. The HTLs were treated with UVO for 0, 5, 10 and 15 min. The 10 min treated OSC showed the best performance and displayed power conversion efficiency (PCE) of 5.24%, much higher than the untreated OSC device. This enhanced performance is mainly driven by improvements in the short circuit current (∼10.82 mA/cm2) as well as the fill factor (∼57%) that is ascribed to the moderate reduction of GO and increased work function (WF) of PEDOT:PSS after UVO treatment, which improved the contact conditions between the HTL and photoactive layer. Consequently, extraction efficiency of the photogenerated holes is increased, while recombination probability of holes and electrons in the photoactive layer is decreased. Moreover, the UVO-reduction of GO and consequently increased conductivity of reduced-GO (r-GO) has been modeled and proved using the density functional theory (DFT) simulation. Meanwhile, the 15 min UVO-treated OSC device showed severe reduction in the PCE that dropped to 2.11%, possibly due to various factors such as decomposition of chemical bonds, significant increase in the series resistance and pronounced drop in the photovoltaic performance parameters