19672 research outputs found
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Challenges and Recommended Solutions in Multi-Source and Multi-Domain Sentiment Analysis
No full textThe massive availability of online reviews and postings in social media offers invaluable feedback for businesses to make better informed decisions in steering their marketing strategies towards users' interests and preferences. Sentiment analysis is, therefore, essential for determining the public's opinion towards a particular topic, product or service. Traditionally, sentiment analysis is performed on a single data source, for instance, online product reviews or Tweets. However, the need to develop a more precise, and more comprehensive result has steered the move towards performing sentiment analysis on multiple data sources. The use of multiple data sources for a particular domain of interest can increase the amount of datasets needed for training a sentiment classifier. Till now, the problem of insufficient datasets for training the classifier is only addressed by multi-domain sentiment analysis. Aiming to equip researchers with a thorough understanding on both multi-source and multi-domain sentiment analysis, this paper aims to identify the underlying challenges of multi-source and multi-domain sentiment analysis, and discuss the solutions applied by the researchers concerned. This paper also offers an insightful discussion of the findings derived from past studies, and based on these, propose some useful suggestions for the future direction of this research area. Findings derived from our review would be beneficial towards guiding researchers towards the future progress and advancement of multi-source and multi-domain sentiment analysis. © 2013 IEEE
Designing the Structural Model of TVET Lecturers’ Professionalism and Generic Skills Based on an Empirical Study in Malaysia
No full textThis study seeks to identify the level of general competency of technical and vocational education and training (TVET) lecturers of construction technology civil engineering (CTCE) of vocational college using the standard model of competency requirement based on grade of lecturer and years of teaching experience. The data were analyzed using the SPSS Version 20.0 software, which involved descriptive statistical method, mean, and standard deviation. Data collection for the assessment phase involves construction technology lecturers from 45 vocational colleges in all the states in Peninsular Malaysia. The respondents of the study were 304 lecturers who taught CTCE courses in vocational colleges from 14 states, namely Johor, Sarawak, and Federal Territory (Kuala Lumpur and Labuan). Finding shows that the professional general competency level of TVET CTCE vocational college lecturers based on years of teaching experience is high with satisfactory interpretation. It also shows that the level of professional competency of TVET CTCE lecturer of vocational college based on grade of the post is high, whereas the level of entrepreneurship skill competency as a whole is at moderate level. There was a slight decrease in the proficiency level profile of the CTCE lecturer who had more than 15 years of experience compared with those with teaching experience of 15 years or less. There found positive relationships between the dimensions of professionalism and the generic skills. The findings of the study will help the Ministry of Education in particular public or private institutions of higher learning in preparing TVET lecturers to become specialized, highly skilled, competent, and efficient in civil engineering courses in the attempt to strengthen the teaching profession, especially in technical and vocational education, which is in line with the aspirations of the 21st-century education. © The Author(s) 2019
Novel Peptides Inhibit Zika NS2B-NS3 Serine Protease and Virus Replication in Human Hepatic Cell Line
No full textZika virus (ZIKV) is a Flavivirus associated with several neurological complications. Currently, there are no vaccines or cures available and an efficient antiviral treatment is urgently needed to combat ZIKV infection. Herein, we targeted ZIKV NS2B-NS3 serine protease with short peptides to inhibit ZIKV replication in human hepatic cell line (WRL-68). The short peptide inhibitors were designed using Hyperchem 8.0.10 software. Docking energy and binding configuration were calculated using HADDOCK webserver. ZIKV NS2B-NS3 protease was produced as a recombinant single peptide in Escherichia coli and the protease activity was examined by measuring the cleavage of a fluorescent substrate in the presence of the peptides or aprotinin as a standard protease inhibitor. Computational analysis revealed that the short peptides, AYA2 and AYA9, exhibited lower docking energy to ZIKV protease than aprotinin. Both peptides also possessed lower half maximal inhibitory concentration (IC50), 30.9 and 22.1 µM respectively, against ZIKV protease activity when compared to aprotinin (35.4 µM). Interestingly, AYA2 and AYA9 exhibited minimal cytotoxic effects in WRL-68 cells and showed considerable inhibition against ZIKV replication in vitro at half maximal effective concentration (EC50) of 40.73 ± 2.3 µM and 34.65 ± 1.8 µM respectively. Fusion of these two peptides to MAP30 peptide substantially reduced the IC50 of ZIKV protease inhibition to 1.1 µM and inhibited ZIKV replication at EC50 of 0.5157 ± 0.03 µM. In sum, we reported novel peptides that effectively inhibited ZIKV replication in vitro. This study represents a cost-effective strategy of developing peptide inhibitors by shortening the peptides and producing them in recombinant form. © 2019, Springer Nature B.V
Quantification of Berberine in Berberis vulgaris L. Root Extract and Its Curative and Prophylactic Role in Cisplatin-Induced In Vivo Toxicity and In Vitro Cytotoxicity
No full textCisplatin is amongst the most potent chemotherapeutic drugs with applications in more than 50% of cancer treatments, but dose-dependent side effects limit its usefulness. Berberis vulgaris L. (B. vulgaris) has a proven role in several therapeutic applications in the traditional medicinal system. High-performance liquid chromatography was used to quantify berberine, a potent alkaloid in the methanolic root extract of B. vulgaris (BvRE). Berberine chloride in BvRE was found to be 10.29% w/w. To assess the prophylactic and curative protective effects of BvRE on cisplatin-induced nephrotoxicity, hepatotoxicity, and hyperlipidemia, in vivo toxicity trials were carried out on 25 healthy male albino Wistar rats (130–180 g). Both prophylactic and curative trials included a single dose of cisplatin (4 mg/kg, i.p.) and nine doses of BvRE (500 mg/kg/day, orally). An array of marked toxicity effects appeared in response to cisplatin dosage evident by morphological condition, biochemical analysis of serum (urea, creatinine, total protein, alanine transaminase, aspartate transaminase, total cholesterol, and triglyceride), and organ tissue homogenates (malondialdehyde and catalase). Statistically-significant (p < 0.05) variations were observed in various parameters. Moreover, histological studies of liver and kidney tissues revealed that the protective effect of BvRE effectively minimized and reversed nephrotoxic, hepatotoxic, and hyperlipidemic effects caused by cisplatin in both prophylactic and curative groups with relatively promising ameliorative effects in the prophylactic regimen. The in vitro cell viability effect of cisplatin, BvRE, and their combination was determined on HeLa cells using the tetrazolium (MTT) assay. MTT clearly corroborated that HeLa cells appeared to be less sensitive to cisplatin and berberine individually, while the combination of both at the same concentrations resulted in growth inhibition of HeLa cells in a remarkable synergistic way. The present validated the use of BvRE as a protective agent in combination therapy with cisplatin. © 2019 by the authors. Licensee MDPI, Basel, Switzerland
Selective harmonic elimination method for unequal DC sources of multilevel inverters
No full textThis paper presented an analytical and closed-form solution for the harmonic contents that were injected in the five-level inverters from asymmetrical DC sources or batteries which were suitable for renewable energy sources. In the five-level inverters, two DC sources V1 and V2 were used to synthesize the output voltage. Therefore, two transcendental equations were formulated for the fundamental and the third harmonic orders based on the unequal DC sources V1 and V2. These transcendental equations were solved analytically for low switching control technique. The proposed solution included the modulation index change which resulted in changing the fundamental component. Therefore, two switching angles are formulated and solved analytically to control the amplitude of the fundamental voltage and cancel the third order harmonic. A well-known third order equation was generated. Thus, a closed-form solution for the above two switching angles will be generated in terms of the modulation index. The proposed solution was tested for a wide range of V1/V2 ratio. Some selected simulation and experimental results were provided to validate the proposed method for wide ranges of both modulation index and V1/V2 ratio. © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group
Novel reservoir system simulation procedure for gap minimization between water supply and demand
No full textIn recent years, with the quick growth of the economy and living standards in Malaysia, keeping up with the water demand is essential for the growth of cultivation, domestic and industrial. With the merits of having dams and reservoirs, water releases from dams are usually used to respond to the water requirements of downstream dams. To match the practical water requirement considering spatial and temporal conditions, a novel optimization operation model has been formulated for minimizing the gap between the water release from a dam and the water requirement. In this context, there is a need to develop an optimization model to alleviate the complexity and multidimensionality of a dam and reservoir as water supplies and the water demand system. In this research, an optimization algorithm, namely, the shark machine learning algorithm (SMLA) that has high inertia for obtaining its targets, is proposed that mimics the natural shark process. The major objective for the proposed model is attaining the minimum difference between the water demand volume and water release. To examine the proposed model, SMLA has been utilized in determining the optimal operation policies for Timah Tasoh Dam, located in Malaysia. A new procedure to evaluate the performance of optimization models by integrating reservoir inflow forecasting with operational rules generated by optimization models has been proposed. Accordingly, two predictive models, namely, radial basis function neural network (RBF-NN) and support vector regression (SVR), have been developed to forecast monthly reservoir inflow. The test results revealed that the SVR forecasts monthly reservoir inflow better than the RBF-NN model. Additionally, the SMLA attained more reliable, resilient and less vulnerable results in the operation of the reservoir system compared to that of other optimization models. In addition, SMLA has demonstrated a significant change in the performance indicator values when using forecasted reservoir inflow data rather than deterministic reservoir inflow data
Molybdenum disulfide nanosheet decorated with silver nanoparticles for selective detection of dopamine
No full textA metal-inorganic composite, comprises of silver-molybdenum disulfide nanosheets (Ag@MoS2) was synthesized at low temperature. The Ag@MoS2 composite was drop-casted onto a glassy carbon electrode (GCE) for a highly selective dopamine (DA) detection in the presence of interfering compounds such as uric acid (UA) and ascorbic acid (AA). The physicochemical analysis of the nanosheets was carried out with X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The as-prepared Ag@MoS2-modified GCE displayed excellent electrocatalytic activity toward DA oxidation, with a 0.2 μM detection limit at a signal-to-noise ratio of 3 and an extensive linear detection range from 1 μM to 500 μM (R2 = 0.9983). The fabricated non-enzymatic electrochemical sensor demonstrated superior selectivity and stability for the detection of DA with the removal of AA and UA interfering compounds
Synthesis, characterization and electrochemical properties of cadmium sulfide – Reduced graphene oxide nanocomposites
No full textNowadays, research interest is speedily growing for fabrication of semiconductor metal sulfide nanoparticles. Proper optimization of process variables for the synthesis process can ensure tunable morphologies and distinct characteristics. Appropriate synthesis strategy can alter their electrical, optical and catalytic properties significantly. A simple, one step, the hydrothermal approach has been undertaken to prepare CdS/rGO nanocomposite here. This technique ensures fabrication of graphene-based nanocomposites with outstanding electro-catalytic characteristics using a facile route. The structural, morphological and the electrochemical properties of the synthesized sample were observed. Surface morphological features together with its phase was identified using FESEM, TEM, and XRD analysis. The crystalline phase of the synthesized sample was confirmed from the X-ray diffraction pattern. Surface functional groups of the synthesized sample were analyzed using the FTIR and FT-Raman analysis. The optical characterization of the CdS and CdS/rGO nanocomposite were examined. The FESEM and TEM images were used to illustrate the surface morphology and particle size of the CdS and CdS/rGO nanocomposite. The elemental composition of the synthesized sample was evaluated using EDAX analysis. In this research, the values for dielectric loss, dielectric constant, and resistivity and AC conductivity of the synthesized samples were determined. Thus, the overall electrochemical features of the prepared sample were evaluated. The results elucidated here showed that the synthesized sample can be used as potential electrode materials for supercapacitor ensuring high energy
Passively Q-switched fibre laser utilizing erbium-doped fibre saturable absorber for operation in C-band region
No full textIn this paper, a stable and robust all-fibre passively Q-switched erbium-doped fibre laser (EDFL) emitting at 1558 nm is described. The proposed laser utilizes an 11 cm long erbium-doped fibre as saturable absorber (SA). The fibre SA features a linear optical absorption of about 13 dB in the Q-switched EDFL operating regime. By elevating the input pump power from the threshold of 60 mW to the maximum available power of 142 mW, a pulse train with a maximum repetition rate of 86 kHz, minimum pulse width of 3.39 µs, maximum average output power of 10.5 mW, maximum pulse energy of 122 nJ and maximum peak power of 36 mW are obtained. The signal to noise ratio (SNR) of the spectrum is measured to be around 70 dB. This fibre SA is simple, reliable, compact and alignment free. Thus it is suitable for making a portable pulse laser source
Synthesis and characterization of α-Fe2O3/polyaniline nanotube composite as electrochemical sensor for uric acid detection
No full textWe report the synthesis of α-Fe2O3/polyaniline nanotube (PAn NTs) composite as an electrochemical sensor for uric acid (UA) detection. Field emission scanning electron microscopy (FESEM) indicates a hexagonal shape of the α-Fe2O3 while a nanotube morphology of the PAn. Impedance spectroscopy results confirm a significant decrease in the charge transfer resistance of the glassy carbon electrode (GCE) modified with α-Fe2O3/PAn NTs due to the presence of PAn NTs. The results show that the increase in the conductivity of α-Fe2O3 in the presence of PAnNTs could improve the catalytic performance of α-Fe2O3/PAn NTs composite, compared to the pure α-Fe2O3 nanoparticles. From differential pulse voltammetry, a linear working range for the concentration of UA between 0.01 µM and 5 µM, with a LOD of 0.038 µM (S/N = 3) was obtained. The sensitivity of the linear segment is 0.433 μA µM−1. The reliability of the modified electrode towards the detection of UA was investigated in the presence of interfering acids such as ascorbic acid, citric acid and succinic acid