Universiti Kebangsaan Malaysia
  • Bangi, Selangor, Malaysia
Recent publications
Neurodegenerative diseases are often associated with the accumulation of oxidative stress and neuroinflammation. Edible bird’s nest (EBN) is a glycoprotein (sialylated mucin glycopeptides) found to be beneficial against neurodegenerative diseases. Antioxidative, anti-inflammatory, and anti-apoptotic properties of EBN in preserving neuronal cells were widely researched using in vitro and in vivo models. Functional effects of EBN are often linked to its great number of antioxidants and anti-inflammatory glycopeptides. Bioactive compounds in EBN, especially sialic acid, add value to neurotrophic potential of EBN and contribute to neuronal repair and protection. Various studies reporting the neuroprotective effects of EBN, their molecular mechanisms, and neuroactive composition were gathered in this review to provide better insights on the neuroprotective effects of EBN.
This review attempts to delineate the effects and roles of fermented foods on allergic responses (AR), specifically from milk, plant, and meat sources. Evidence for AR alleviation and aggravation were noted for many different fermented food groups. Positive outcomes on AR through fermented foods could be linked to microbial hydrolysis of food allergens, improvement in gut microbiota robustness, and modulation of the immune system that promotes a balance between T helper 1 (Th1) and Th2 cells. Studies on plant-based, non-protein rich fermented foods tend to show more favourable results compared to those on meat-based or protein-rich group. The usage of specific and known starter cultures are helpful in alleviating AR, as in the case for many yogurt, Kefir or Dahi products. Sufficient fermentation time was also deemed important, exemplified in studies that showed inefficient AR reduction through consumption of fresh cheese. However, formation of new allergens through fermentation of certain meat-based foods, or by using specific fermenting microbes (e.g. Penicillium sp.), is possible. Thus, combination of starter cultures and food substrates must be considered in preventing or eliminating AR from intake of these foods. This review may aid consumers to make informed decision during the consumption of fermented food.
In this study, an off-grid photovoltaic (PV) inverter generates three-phase power to supply the local load and is controlled using an optimized fuzzy logic controller (FLC) using particle swarm optimization (PSO) to control the photovoltaic system’s output. The PSO improves the three-phase inverter’s membership functions (MFs) by using the objective function as mean square error (MSE) for voltage at the output. The best-obtained outcome of the PSO is used to trigger the gate drives of the PWM inverter. The system has been simulated and modeled using MATLAB/Simulink to validate the performance of the proposed method and shows the best control output from the inverter and has been tested in a different types of loads. The motivation for using FLC to control the shape of MFs was about saving time consumed in trial and error. The results present an output of three-phase voltage and current waveform subjected to different loading conditions.
Heavy metal ions present in water bodies are of great concern for human health, aquatic life, and environmental sustainability. The heteroatoms present in small organic molecule-based sensors endow them with the ability to coordinate as ligands with different metal ions. Due to increasing interest in human health and water quality maintenance, the detection of heavy metal ions is of vital importance. The small organic molecules due to their facile synthesis and efficient chemosensing properties have been employed repeatedly for the detection of environmental pollutants. In this review article, we considered current advances in the field of fluorescence sensors developed for the sensing of heavy metals (having higher toxicity concerns) in water bodies. Further, the chemosensing preferences, mechanism, and detection limits are compared and discussed providing valuable perceptions for the future development of fluorescent sensors intended for heavy metal sensing. By highlighting the limitations and challenges that already synthesized probes face, this critical and comprehensive review will help and support the design of highly efficient, sensitive, and selective sensors for heavy metal detection in the future. The analysis of the recent advancements reveled the small organic molecules’ potential with efficient sensing performances to broaden the scope of practical applications. free full text link: https://authors.elsevier.com/c/1g8Ws7tGO~KHZM
Carica papaya leaf has a potentially well-known therapeutic effect in accelerating human blood platelet counts against dengue fever and dengue haemorrhagic fever. However, consuming the extract was considered troublesome due to its bitter taste. The fresh papaya leaves were extracted into two types of preparation: a) Fresh Papaya Leaves Extract (FPL) and b) Papaya Leaves with Saponin Reduction Extract (PLSR). This was followed by the determination of the best edible O/W emulsion formulation of both different extracts with virgin coconut oil (VCO) and whey protein (WP) as surfactant. Through Ternary Phase Diagram (TPD), the optimum ratio (w/w) of FPL/PLSR: VCO: WP were 63: 16: 21 and 65: 16: 19 respectively. Both formulas were examined for their physicochemical properties including pH, creaming index (CI), contact angle and droplet size measurement. The human bronchial epithelium cell (BEAS-2B) was treated using both emulsions for 72 hrs of cell growth response (EC50). The result shows that both FPL and PLSR formulations were slightly acidic and exhibited stable emulsion with no creaming formation (CI) up to 24 hrs of storage (25 ℃). Next, FPL emulsion shows 3 times higher wettability and 4 times bigger nanoparticle size than PLSR. These properties can affect the emulsion absorptivity in the targeted cell microenvironment. Remarkably, the BEAS-2B cell viability (%) for each emulsion was relatively elevated within 24 hrs and increased to more than 100% at 48 and 72 hrs of exposure. This might hugely represent its potential in repairing damaged blood vessels due to dengue haemorrhagic fever. Besides, the EC50 value also indicated low levels of concentration needed to exponentially increase cell growth and safe for dengue fever treatment. For that reason, the recommended effective dosage by the Ministry of Health (Malaysia) (MOH) for both FPL and PLSR emulsions is two tablespoons twice a day for three consecutive days of treatment (equally to the effective dosage of 102 g extract).
In Malaysia, many university students have different views on saving management based on different factors. Therefore, this study aims to examine the intention and behaviours towards saving among Malaysian students. A cross-sectional design was adopted to collect quantitative data from 307 Malaysian students and universities in Klang Valley. Furthermore, the theory of planned behaviour (TPB) was applied, followed by an extension of TBP by embedding the constructs involved in the behaviour of saving. The results indicated that financial attitude, financial socialisation, financial capability, and self-control have a positive and significant effect on saving intention and behaviour among university students in Malaysia. However, financial education did not have a significant impact on saving intention and behaviour. Notably, the results offer a guideline to policymakers and awareness campaign to increase saving behaviour and financial management. The relevant agencies should focus on improving financial attitude, financial socialization, financial capability, financial education, and self-control towards saving intention and behaviour for their future planning in education and life.
The aspects of life and industry and also model and principles of business has changed significantly parallel with the phenomena of rapid growth in today’s digital age. In addition, the Information and Communications Technology (ICT) will give significant affects to digital economy. Therefore, in the case of fully utilizing the technology, conventional business systems is highly recommending to replace by ICT which is believed as the best platform that could lead the firm to be more competitive in the current market. On the other hand, one of the factor to ensure the effectiveness and efficiency of the business is management accounting information (MAI). MAI is a primary information source for planning, decision-making and control which is crucial for business in achieving competitive advantage. The main focus of this study is to investigate the relationship between MAI and performance moderated by digital inclusion among SMEs in Malaysia. Resource Based View (RBV) has been used as the underpinning theory, which expect that digital inclusion moderates the relationship between MAI and performance. The data was collected by survey method using questionnaires and distributed to SMEs in Malaysia. Based on the samples of 338 respondents the study employs Structured Equation Model (SEM) using SmartPLS 3 software to analyze the data. The results reveal that MAI (include broad scope, timeliness and integration) has a positive direct effect on performance. However, there is no evidence that digital inclusion moderating the relationship between MAI and performance. The finding of this study suggest that SMEs in Malaysia should include all information needed in their management accounting system., quickly and effectively disseminate the information to the relevant parties and integrate the information between departments in order to improve the performance of the organization.
The study examines the customers' perception towards buying insurance online with factors taken from the theory of planned behavior like attitude, subjective norm, and perceived behavioral control among the Chinese working adults. The research collected cross-sectional survey-based data. The collected data analyzed with the structural equation modeling with SmartPLS 3.1. The study's results offer empirical support that internet trustworthiness positively influences the attitude towards making purchases online, normative structure positively and significantly impacts the subjective norms towards internet purchase, and user internet self-efficacy significantly influences the perceived behavioral control for the internet purchase. The results confirm that the attitude and perceived behavioral control positively and significantly influence intention to purchase insurance online. Intention to purchase insurance online significantly predicts the behavior of purchasing insurance online. Current research establishes significant empirical evidence that the behavioral attitudinal beliefs build on the behavioral beliefs towards the making purchase over the internet. The subjective norms for internet purchase are not supportive, and consumers are finding less social support to buy financial products over the internet. Current work extends the theory of planned behavior with the behavior beliefs that formulates the attitudinal beliefs that leads to the development of the internet and purchase behaviors.
Given the significance of electronic word of mouth for digital edge, this research evaluated the influence of selected determinants towards brand image and electronic word of mouth among airline passengers in Malaysia. A total of 400 random airline passengers were participated in this survey. The results showed that the components for social media marketing activities components are entertainment and trendiness. It is revealed that social media marketing activities, value consciousness, and brand consciousness can positively and significantly enhance brand image. Brand image shown a positive influence on electronic word of mouth among the Malaysian airline passengers. Thus, brand image can significantly mediate the effects of social media marketing activities, value consciousness, and brand consciousness eWOM across the sample of the study. Apart from extending the current e-marketing management literature, the study contributed to the airline companies, particularly in Malaysia, to set their marketing plans using social media, value, and brand consciousness in developing customers engagement through electronic word of mouth.
Background and Motivations: Continuous Blood Pressure (BP) monitoring is crucial for real-time health tracking, especially for people with hypertension and cardiovascular diseases (CVDs). The current cuff-based BP monitoring methods are non-invasive but discontinuous while continuous BP monitoring methods are mostly invasive and can only be applied in a clinical setup to patients being monitored by advanced equipment and medical experts. Several studies have reported different techniques for predicting BP values from non-invasive Photoplethysmogram (PPG) and Electrocardiogram (ECG) signals. Apart from BP readings, estimating ABP waveforms from non-invasive signals can provide vital body parameters such as Mean Arterial Pressure (MAP) which can be used to determine poor organ perfusion, nutrient supply to organs, and cardiovascular diseases (CVDs), etc. Methods It is challenging to estimate ABP waveforms while maintaining a high BP prediction performance and ABP waveform pattern. In this work, we propose a novel approach for ABP waveform estimation by separating the task into BP prediction and a normalized ABP waveform estimation through segmentation from PPG, PPG derivatives, and ECG signals, and combining afterward. We propose the Nested Attention-guided BiConvLSTM Network or NABNet which uses LSTM blocks during segmentation for better handling of the existing phase shifts between PPG, ECG, and ABP signals. Several experiments were performed to improve the ABP reconstruction performance, which was combined with an existing BP prediction pipeline for the non-invasive estimation of ABP waveforms. Results The proposed framework can robustly estimate ABP waveforms from PPG and ECG signals by reaching a high MAP performance and low construction error while maintaining the overall Grade A performance of the BP prediction pipeline. Conclusion Linearly translating the range-normalized, synthesized ABP segments by corresponding SBP and DBP predictions from the BP prediction pipeline managed to robustly estimate ABP waveforms from PPG and ECG signals.
Artificial intelligence (AI)-powered autonomous vehicles (AVs) are one of the most disruptive technologies with potentially wide-ranging social implications, including improvements in passenger/driver safety, environmental protection, and equity considerations. The current research extends the UTAUT2 model in the context of fully AVs (level 5 automation) to determine and rank determinants of intention to adopt AVs. Collected data from 378 respondents were analysed by a hybrid approach employing partial least squares (PLS) complemented by the Adaptive Neuro-Fuzzy Inference Systems (ANFIS) technique. According to the findings, five major determinants emerged: trust, hedonic motivation, social influence, compatibility, and effort expectancy. Furthermore, compatibility positively moderates the association between performance expectancy and intention to use AVs. The findings shed light on determinant factors, their level of importance, and the potential interplay between them in shaping individuals' intention to adopt and use AVs. Furthermore, the current research provides valuable insights to carmakers, technology developers, and practitioners on determinants of AVs adoption, assisting them in devising effective AVs-related strategies.
The alcohol fuel cell is a promising technology that will replace conventional energy production with higher energy conversion efficiency and less pollutant emission. However, the catalyst faces some challenges, and it requires modification. Among various modification methods, producing bimetallic alloys has delivered better performance than monometallic noble metal catalysts. Five catalyst models, Pd (1 1 1), Ag (1 1 1), Pd3Ag (1 1 1), PdAg (1 1 1), and PdAg3 (1 1 1), have been studied in this work in terms of structural, electronic, and adsorption molecules properties through density functional theory (DFT) studies. The structural and electronic properties of the modified catalyst model show the ligand and strain effect on the alloy with the addition of silver as second metal promotes the adsorption capability; however, the catalytic activity heavily depends on the alloy composition. Searching for active sites was also carried out by adsorption of selected atoms and molecules and used as a preliminary study to find possible active sites for alcohol electrochemical reaction at the anode in a direct liquid fuel cell (DLFC). The Pd3Ag (1 1 1) catalyst exhibits better adsorption ability on atomics, simple molecules, and alcohol/polyol molecules (methanol, ethanol, and glycerol). This work also carried out catalytic activities for ORR at the cathode. Pd3Ag (1 1 1) was found to be the most suitable for the ORR. The presence of the Ag atom showed theoretically a promising metal–metal combination for an excellent catalyst that might replace monometallic catalyst and produce a new tri-metallic catalyst in the future for the application in DLFCs, especially with glycerol. Even by replacing the 75% of Pd surface with Ag, the adsorption strength on the glycerol is remarkable, positively contributing to the oxidation reaction. The Ag metal is a suitable second metal candidate for the alloy to oxidize molecules with a longer carbon chain similar to or more than glycerol.
Developing facile strategies for anchoring transition-metal nanoparticles (M-NPs) on support materials to make their easy handling, and nascent technologies to advance their applications towards large scale sustainable catalysis are highly demanding. Herein, one-pot strategy is reported for the in-situ immobilization of palladium nanoparticles (Pd-NPs) on highly porous polyurea (PPU). In this approach, Pd acetate (PdAc) solution in tolylene-2,4-diisocyanate (TDI) was gradually added in H2O/acetone (3/7 wt%) mixture under stirring at ambient conditions, followed by the addition of NaBH4 to get Pd/PPU. The combined outcomes of characterizations of resulting Pd/PPU by NMR, SEM, ICP-OES, XRD, XPS, TEM, and BET techniques revealed the successful immobilization of uniformly dispersed Pd-NPs (dmean = 6.2 nm) on PPU having hierarchically porous morphology with specific surface area of 127.13 m²/g. The hybrid composite, Pd/PPU, was used in packed-bed reactor to evaluate its performance as the continuous flow catalytic converter for several toxic organic and inorganic pollutants, as well as their mixture in aqueous medium with the assistance of suitable reductants. The effects of Pd loading, feed concentrations, and permeation flux on the activity of Pd/PPU are discussed. A remarkable permeation flux of 21,000 Lm⁻² h⁻¹ (LMH) with > 99% of pollutant’s reduction efficiency and high stability (no change for 20 h used) of Pd/PPU in packed-bed continuous flow catalytic converter were obtained, far better (>10 times) to compare with reported results (2000 LMH) so far. This work therefore provides facile strategy to get PPU-based Pd, a high-performance catalyst for continuous flow reduction of toxic contaminants from wastewaters.
although there are outstanding issues. First, the overwhelming majority of reviewers are from developed countries, although evidence suggests participation by developing country reviewers increased between the Fourth and Fifth Assessments. Second, earlier sections of chapters are more densely reviewed than later ones. This is true even when executive summaries are removed from analysis. In consequence, some sections on specialised topics may escape in-depth review. Thirdly, those review comments which are received make a valid and valuable contribution to the scientific development of chapters. We suggest how outstanding issues could be addressed, including through enhanced reviewer recognition, a wider role for review editors, adherence to mandated page lengths from early in the process, reviewer training, and consistency in reporting to allow systematic evaluation. Making such changes will result in more transparent, consistent and representative processes delivering reviews which effectively contribute to the credibility and legitimacy of future Global Environmental Assessments and, ultimately, their recognition and contribution.
In this work, we develop a pseudoinverse-based static finite-element solver to model the elastic deformation and non-local brittle fracture of solids. The pseudoinverse of the finite-element stiffness matrix is calculated using a QR decomposition-based method which is faster than using the traditional approach based on the singular value decomposition method. This new finite-element framework has two advantages: (1) the finite-element equations can still be solved even when the finite-element stiffness matrix is singular, and (2) there is no need for introducing an artificial elastic rest energy or viscous regularization for the sole purpose of keeping the finite-element stiffness matrix non-singular in order to solve the finite-element equations. We also show that the proposed method is robust in solving chosen boundary value problems involving the elastic deformation and abrupt non-local mode I and mixed-mode brittle fracture of solids when compared to the traditional element kill method where a small but finite residual stiffness is maintained at a material in order to prevent the finite-element stiffness matrix from being singular. Hence, this proposed method allows the modeling of separation/fragmentation of solids when fracture occurs. Finally, we use the new computational framework to model the fracture of PMMA beam samples at room temperature. By calibrating the material parameters in the constitutive theory using analytical methods and fitting to a Mode I fracture experiment force–displacement response, we show that our newly-proposed computational method is able to predict the experimental fracture loci and crack propagation characteristics in PMMA beam samples undergoing mixed-mode fracture conditions to good accord.
Naturally regenerated (NR) mangroves offer an excellent passive approach for climate change mitigation and adaptation under UN decade of restoration program. However, the support of NR mangroves on total ecosystem carbon (TEC) stocks and sequestration potential remained unclear across forest stand development process that can significantly vary spatially and temporally due to regeneration age. Using the ‘space for time’ approach, this study quantified the TEC stocks along the Merlimau - Kuala Sebatu fringing mangrove habitat expansion chrono-sequence that comprised of 3, 6, 12, 18, 25 years age and intact stands. We also estimated the carbon (C) sequestration potential of each stand-age by comparing with un-vegetated mudflats as control. We collected aboveground tree, belowground root, downed woody debris, litterfall and soil core up to 2 m for TEC quantification and C sequestration. Mean TEC stocks ranged from 232 ± 69 to 296 ± 49 Mg C/ha for NR3 and NR25 respectively at the study area. TEC stocks from different aged NR and intact mangroves were not significantly different from each other and therefore did not affect by age. Aboveground trees C and downed wood C pools were significantly affected by stand-age. In contrast, sediment C stocks (representing up to 80 %) remained generic over many years, driving the constant of TEC stocks in this study. Equally affected by age, the NR mangroves sequestered total C of 2.28 to 17.38 (mean ± SE: 7.36 ± 1.88 Mg C/ha yr⁻¹), with younger stands (NR3) holding almost six times higher total C sequestration rates than older mangroves (NR25). Our study suggests that highly suspended sediments driving from upstream, especially in the younger mangrove stands at a lower elevation, supports higher bulk density and C accumulation rate in the sediment as they expand seaward. This study proves that NR mangroves comprised primarily of younger mangrove stands can be a C sequestrator powerhouse that promises nature-based climate solutions through avoidance and management. Though, future research is needed to understand how better management and conservation practices can affect or towards increasing trend of TEC especially sediment carbon stock that holds almost 80 % of total TEC.
This paper aims to develop a natural-disaster theme museum visitor satisfaction model by integrating authenticity, involvement, and destination image by applying Arnolds’ theory of emotion. This study takes place at Aceh Tsunami Museum, Indonesia. An Importance-Performance Map Analysis is applied to identify the performance and the importance of the museum attributes in determining visitor satisfaction. Using an adapted questionnaire, 199 usable data gathered from the Aceh Tsunami Museum were analyzed using Partial Least-Squares Structural Equation Modelling (PLS-SEM). The result showed that authenticity, involvement, and destination image as the predictors of visitor satisfaction with image as the highest predictor of visitor satisfaction. This study also found that image plays as a mediator in the relationship between authenticity, involvement and satisfaction. Subsequently, this study identifies two paths to reach visitor satisfaction in the natural-disaster theme museum. They are authenticity-image-satisfaction and involvement-image-satisfaction with the latter path have higher contribution to the visitor satisfaction. From IPMA analysis, it is found that activities that adding knowledge to the visitors are deemed important to create visitors satisfaction.
The swiftlet’s nest is an edible bird’s nest (EBN) produced from dried gelatinized saliva secreted by swiftlets during the breeding season. It is widely used in industries for its high nutritional values and health benefits. However, the utilization of ESN is restricted due to its physicochemical properties, such as insolubility. The recently invented bioactive ESN hydrolyzate is reported to improve the ESN’s solubility, functional and nutritional properties to broaden its application. This study has produced bioactive ESN hydrolyzates with different hydrolysis periods to investigate the optimum conditions to achieve maximized degree of hydrolysis (DH) and to compare the physicochemical differences. The result revealed that optimum ESN hydrolysis was at 90 minutes, in which the DH and enhanced solubility (three folds) indicated a complete breakdown of glycoprotein into bioactive glycopeptide. This result is in line with the physicochemical analyses result. The hydrolysis has significantly decreased (p ≤ .05) the ESN protein content, while the levels for peptide, glycopeptide, polysaccharides, and sialic acid showed the opposite. Interestingly, the amino acid from raw ESN and hydrolyzates in all incubation periods showed no significant difference (p ≤ .05). This result suggests that the ESN biological properties remained unchanged with alcalase hydrolysis. Therefore, the findings in this study confirm the feasibility of bioactive ESN hydrolyzate as a versatile product suitable for various industries in utilizing ESN in whole instead of as extracts.
Nigella sativa L. is a fragrant plant that belongs to the Ranunculaceae family. It is commonly used as a form of traditional medicine in Middle-Eastern countries. In this study, Nigella seed oil from Saudi Arabia was extracted using the cold press and Soxhlet methods to investigate the effects of solvents polarities on yield and antioxidant properties. The analysis revealed that the highest yield (40%) of oil was obtained with ethanol solvent. The aqueous methanol extract the highest level of total phenolic compounds (239 mg GAE/g). Moreover, the methanol extract showed the most elevated 2,2-Diphenyl-1-picrylhydrazyl radical rummaging assay, at 59%. The ferric reducing and antioxidant power activities of the oils extracted with ethanol and tetrahydrofuran were 13,199 and 13,326 mmol Fe2+/100 g dry weight, respectively. Thus, the findings show that a high level of natural antioxidants can be derived from Nigella sativa oil extracted by ethanol solvent.
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21,226 members
Naif H. Al-Hardan
  • Department of Applied Physics
Habibah Ahmad
Simon Kumar Das
  • Department of Earth Sciences & Environment
Caryn Mei Hsien Chan
  • Faculty of Health Sciences
Saidah Saad
  • Faculty of Information Science and Technology
Universiti Kebangsaan Malaysia (UKM), 43600, Bangi, Selangor, Malaysia
Head of institution