19672 research outputs found
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Liquefaction of natural rubber to liquid fuels via hydrous pyrolysis
No full textIn this study, the natural rubber (NR) was liquefied to produce liquid fuels using hydrous pyrolysis technique. The study was performed in the autoclave batch reactor at different temperatures (300–400 °C), with different water to natural rubber mass ratios (1:1–5:1) and different reaction times (15–75 min). The effect of different parameters then was evaluated on the liquid product in term of quantity and quality. The results showed that the highest liquid yield of 76 wt% was obtained at temperature, H2O/material mass ratio and time of 375 °C, 3:1 and 30 min respectively. Among the parameters, temperature was found to be the most important parameter, showing a notable positive effect on the liquid oil quality and quantity. The characterization results showed that the oil had high energy density, low oxygen and sulfur contents, and non-acidic. The GC–MS analysis showed that the obtained oil was dominated by alkenes, aromatics and alkyls. From all characteristic results it showed that the oil from NR was more suitable to be used as fuel compare to the oil derived from scrap tire, where the study on hydrous pyrolysis of scrap tire was also provided in this manuscript as comparative study. In addition, the production of oil from the hydrous pyrolysis of NR in Malaysia could add to the energy potential about 15 PJ/year or equivalent to 2.5 million barrels of oil per year
Oral health care for the elderly population in Malaysia: A review of current status and future direction
No full textPoor oral health status among the elderly population in Malaysia could be associated with various limitations in accessing oral health care services experienced by these individuals. This review discusses government policies and services available to support oral health needs of the elderly population in Malaysia. It also discusses the current status of oral health and dental treatment needs of this patient cohort, as well as the level of utilization of oral health care services. Recommendations to address the various issues are provided to serve as guidance to policy makers in formulating an effective plan aimed at improving the status of oral health and the services available for elderly individuals in the country
Dioscorea bulbifera induced apoptosis through inhibition of ERK 1/2 and activation of JNK signaling pathways in HCT116 human colorectal carcinoma cells
No full textDioscorea bulbifera, also known as air potato, has been cultivated as food crop mainly in tropical countries in Asia and Australia. The tubers are edible and have often been used in Traditional Chinese Medicine (TCM) and Ayurvedic medicine to treat cancer, diabetes, thyroid disease, and inflammation. This study aimed to investigate the effects of D. bulbifera on HCT116 human colorectal carcinoma cells and to unravel the plausible mechanisms underlying its apoptotic effects. The ethanol crude and fractions (hexane, ethyl acetate and water) of D. bulbifera were subjected to cell viability MTT assay against various cancer cell lines. The lowest IC50 of the extract and fractions on selected cancer cells were selected for further apoptosis assay and western blot analysis. HCT116 cancer cells were treated with D. bulbifera and stained with Annexin/PI or Hoechst 33342/PI for preliminary confirmation of apoptosis. The dissipation of mitochondria membrane potential (MMP) was determined by flow cytometry. The protein expressions of apoptosis-related proteins such as Bcl-2 family, caspases, Fas, PARP, ERK1/2 and JNK were detected by western blot analysis. Moreover, the HCT116 cells were treated with UO126 and SP600125 inhibitors to verify the involvement of ERK1/2 and JNK protein expressions in inducing apoptotic cell death. Based on the result, D. bulbifera ethyl acetate fraction (DBEAF) exhibited the most compelling cytotoxicity on HCT116 cells with an IC50 of 37.91 ± 1.30 µg/mL. The induction of apoptosis was confirmed by phosphatidylserine externalization and chromatin condensation. Depolarization of MMP further conferred the induction of apoptosis was through the regulation of Bcl-2 family proteins. Activation of caspase cascades (caspase-3, -9, -8 and -10) was elicited followed by the observation of cleaved PARP accumulation in DBEAF-treated cells. Furthermore, death receptor, Fas was activated upon exposure to DBEAF. Collective apoptotic evidences suggested the involvement of intrinsic and extrinsic pathways by DBEAF in HCT116 cells. Interestingly, the attenuation of ERK1/2 phosphorylation accompanied by the activation of JNK was detected in DBEAF-treated cells. In conclusion, the findings revealed that DBEAF induced apoptosis through intrinsic and extrinsic pathways involving ERK1/2 and JNK
Q-switched thulium/holmium fiber laser with gallium selenide
No full textA passively Q-switched thulium/holmium fiber laser with a gallium selenide (GaSe) saturable absorber (SA) is proposed and demonstrated for the first time. The GaSe based SA is prepared by mechanical exfoliation and inserted into the proposed laser cavity to generate Q-switched pulses. Stable Q-switching operation is achieved at 1986.0 nm, with output pulse repetition rates ranging from 22.9 kHz to 32.3 kHz over a pump power range of 112.0 mW to 235.0 mW. The generated Q-switched pulses have a maximum pulse energy of 120.3 nJ and minimum pulse width of 6.9 μs. The proposed thulium/holmium fiber laser with GaSe SA will be able to cater to multiple applications requiring pulsed laser outputs in the 2.0 μm region
Impact of currency reform on Chinese external trade
No full textThis paper discusses the impact of Chinese authorities’ 2005 decision to abandon the fixed exchange rate regime on China’s international trade. After such reform, exchange rate volatility tend to arise and that can affect a country’s international trade. As the Chinese economy is highly reliant on international trade, the consequences of exchange rate reform may be serious. Our findings reveal that the influence of exchange rate changes is negative only on China’s imports. There is no such influence for its exports. Therefore, the exchange rate fluctuations after the 2005 reform are encouraging for China’s trade balance. On the other hand, there is no significant effect on exchange rate volatility
Interference reduction using MMSE-DFE equalizer with one-third ICI-SC STFBC for MIMO-OFDMA system
No full textOrthogonal frequency division multiple access (OFDMA) allows simultaneous low data rate transmission for several users. However, as one symbol interferes with subsequent symbol, it will produce a phenomenon called intersymbol interference (ISI) which has similar effect as noise and thus making the communication less reliable. Besides that, Doppler spread due to channel time-variation destroys the orthogonality in OFDMA system and degrade the system performance with intercarrier interference (ICI). In order to solve this issue, minimum mean square error-decision feedback equalizer (MMSE-DFE) with one-third (ICI-SC) subcarrier mapping method using space-time-frequency block codes (STFBC) is proposed. The objective is to minimize both ISI and ICI effects by evaluating pairwise error probability (PEP) and bit error rate (BER) performances. From the simulation results, MMSE-DFE with one-third ICI-SC technique shows the best result for MIMO-OFDMA system with 25% improvement of PEP and 4.8% improvement of BER
Leadership and staff organizational citizenship behaviour in higher education institutions: A quantitative analysis
No full textHigher education institutions are known for producing skilled manpower needed to attain sustainable and holistic development. These institutions cannot achieve their predetermined goals without effective leadership. Leadership is an important factor in an organization. Academic leaders are pivot of change in any higher education institution. As a change agent, the success and failure of the system depend on academic leaders. Their belief and judgment about themselves, attitude towards change and policy tell in every aspect of education system. Therefore, this study examined the impact of leadership self-efficacy and change oriented behaviour on staff organizational citizenship behaviour in higher education institutions. It adopted a quantitative research design. A questionnaire consisting of 40 items was used to gather information from 420 respondents who were randomly selected across 10 different public higher education institutions in Lagos State, Nigeria. Structural Equation Modelling(SEM) was used in analysing the data collected in this study. The findings show that leadership self-efficacy, change oriented behaviour and change policy impact significantly on staff organizational citizenship behaviour. In order to improve staff organizational citizenship behaviour and performance in higher education institutions, academic leaders must display a high self-efficacy, be open to innovation, ensure effective communication and adopt friendly policy that will stimulate staff. If all these are put in place, higher education institutions will be able to achieve their set goals and respond positively to the needs of different stakeholders
Paleoenvironmental reconstruction and hydrocarbon potentials of Upper Cretaceous sediments in the Anambra Basin, southeastern Nigeria
No full textPalynological, organic petrographic, and organic geochemical analyses of the Campanian-Maastrichtian sediments in Akukwa-2 well were carried out to infer their paleoenvironments, origin of the organic matter, and hydrocarbon generation potentials. The TOC values of the analysed sediments range from 0.27–3.02 wt%, while the S2 pyrolysis yield range from 0.55 to 3.35 mg HC/g rock. This indicates that the Nkporo and Mamu sediments possess fair source generative potential. The samples contain Type III-II and Type III kerogen as shown by the present-day HI values between 58 and 292 mg HC/g TOC and pyrolysis-GC data. The organic matter within the sediments is also likely to generate mainly gas. This is in agreement with the petrographic observations, which revealed that the analysed shale samples contain abundant vitrinite macerals, apart from bituminite, alginite, cutinite, and resinite. Also, the sediments are immature to early mature in terms of hydrocarbon generation as indicated by vitrinite reflectance, biomarker maturity, and pyrolysis Tmax data. Biomarker distribution ratios, palynomorphs assemblage, and organic petrographic observations further point out that the organic materials within the sediments were of mixed aquatic and terrigenous origin and were deposited under suboxic paleodepositional conditions. Based on sedimentological, palynological, and biomarker characteristics, the environment of deposition of the analysed sediments was inferred to be a relatively quiet, shallow marine with fluvial incursion, most especially at the upper part of the intervals studied and consequently, it is a delta associated depositional environment with a fluviatile influence. The sediments are therefore suggested to be deposited in a paleogeographic setting close to vegetation source
Automated diagnosis of focal liver lesions using bidirectional empirical mode decomposition features
No full textLiver is the heaviest internal organ of the human body and performs many vital functions. Prolonged cirrhosis and fatty liver disease may lead to the formation of benign or malignant lesions in this organ, and an early and reliable evaluation of these conditions can improve treatment outcomes. Ultrasound imaging is a safe, non-invasive, and cost-effective way of diagnosing liver lesions. However, this technique has limited performance in determining the nature of the lesions. This study initiates a computer-aided diagnosis (CAD) system to aid radiologists in an objective and more reliable interpretation of ultrasound images of liver lesions. In this work, we have employed radon transform and bi-directional empirical mode decomposition (BEMD) to extract features from the focal liver lesions. After which, the extracted features were subjected to particle swarm optimization (PSO) technique for the selection of a set of optimized features for classification. Our automated CAD system can differentiate normal, malignant, and benign liver lesions using machine learning algorithms. It was trained using 78 normal, 26 benign and 36 malignant focal lesions of the liver. The accuracy, sensitivity, and specificity of lesion classification were 92.95%, 90.80%, and 97.44%, respectively. The proposed CAD system is fully automatic as no segmentation of region-of-interest (ROI) is required
Ensuring the well-being of the elderly: Revisiting the role and adequacy of social protection schemes in Malaysia and the Philippines
No full textGlobally, social protection schemes are considered as effective tools in ensuring the well-being of the poor, disempowered and otherwise marginalised people of society. It is applicable in cases of elderly people who are comparatively vulnerable due to their old age, and at times poverty or the lack of financial security. The proportion of elderly people in poverty is higher than that in the working age population, indicating the increasing likelihood of people falling into poverty as they leave or retire from the workforce. Therefore, one way of addressing poverty among the elderly is through social protection mechanisms. Malaysia and the Philippines are two Southeast Asian countries on their way to becoming ageing nations. As such, both these countries have already adopted numerous social protection schemes to ensure the well-being of the marginalised segments of society, including the elderly. Thus, based on existing literature, this paper is an attempt to revisit and re-examine the role and adequacy of existing social protection schemes available in Malaysia and the Philippines