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- PublicationBioassay-guided profiling of quercus infectoria gall extracts using HPLC and their antimalarial activity(2025-01)Malaria is a public health concern as the emergence of drug-resistant malaria parasites causes significant morbidity and mortality annually. The discovery of potent antimalarial drugs derived from medicinal plants is believed to be a crucial strategy for addressing the antimalarial drug resistance crisis. Therefore, the antimalarial properties of crude extracts from Quercus infectoria (QI) galls were investigated through bioassay-guided fractionation. Acetone (QIA) and methanol (QIM) crude extracts have been reported to exhibit promising antimalarial activity against Plasmodium falciparum (3D7 strain) with IC50 values of 5.85 ± 1.64 μg/mL and 10.31 ± 1.90 μg/mL, respectively. These extracts were subjected to fractionation using automated preparative high-performance liquid chromatography (prep-HPLC) to identify the most active fractions. Nine fractions were separated from each extract, of which the fractions QIA6 and QIM6 showed potent antimalarial activity, with IC50 values of 17.65 ± 1.82 μg/mL and 24.21 ± 1.88 μg/mL, respectively. In comparison, the standard antimalarial drug artemisinin had an IC50 value of 0.004 ± 0.001 μg/mL. The fractions of the Quercus infectoria galls exhibited antimalarial activity, which could be attributed to the presence of various secondary metabolites, particularly phenolic compounds such as ellagic acid. The high-performance liquid chromatography (HPLC) analytical method was established for the quantification of ellagic acid as a marker in the Quercus infectoria gall crude extract. All parameters including specificity, precision, accuracy, linearity, limit of detection (LOD) and limit of quantitation (LOQ), were found to be in the acceptable criteria of the ICH guideline. Targeted phenolic compound analysis of the most active fraction was performed by high-resolution liquid chromatography coupled with mass spectrometry (HR-LCMS). HR-LCMS analysis was conducted on the active fractions, QIA6 and QIM6, and revealed that kaempferol-3-O-glucoside, quercetin-3-glucoside, and syringic acid were among the major compounds identified in QIA6, while syringic acid and 3,4-dihydroxybenzoic acid were predominant in QIM6. The correlation between antimalarial activity and phenolic compounds in fractions QIA6 and QIM6 led to the quantitation of four targeted phenolic compounds. Thus, this study showed promising antimalarial activity of Quercus infectoria (QI) galls when fractionation was performed, which can be used as a guideline for future investigations on the molecular mechanism underlying the antimalarial action and further reflect the importance of an in-depth antimalarial investigation.
- PublicationValidation of plasma probe hardware platform for in-situ measurement and monitoring of atmospheric parameters using sounding rocket(2024-04-01)This thesis presents the validation of a plasma probe hardware platform for insitu measurement, accompanied by a real-time communication system. The objective is to create an integrated system that combines a plasma probe hardware platform with a reliable and efficient real-time communication infrastructure. The hardware platform incorporates multiple sensors, including temperature, magnetic, accelerometer, camera, pressure, and GPS, to enhance the understanding of the relationship between in-situ plasma probe measurements and environmental parameters. The real-time communication system ensures seamless data transmission between the platform and the ground station operator during the data collection process, providing valuable realtime access to the collected data. This feature also serves as a redundancy solution in the event of recovery failure, ensuring that data can still be transmitted and monitored even if the platform cannot be recovered. Through this integrated approach, researchers can monitor, analyse, and make informed decisions based on the collected data in real-time, even in challenging recovery scenarios. The validation of the plasma probe hardware platform, coupled with the real-time communication system, advances our capability to study plasma phenomena, offering significant implications for space exploration, atmospheric research, and related scientific endeavours.
- PublicationSynthesis of molecularly imprinted polymer-ordered mesoporous silica adsorbent for batch and fixed-bed column adsorption of chloramphenicol(2024-09-01)This study describes a novel synthesis of a surface-imprinted polymer-ordered mesoporous silica adsorbent for highly selective chloramphenicol (CAP) adsorption using activator regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Initially, ordered mesoporous silica was synthesized by the sol-gel method and functionalized to prepare a silica-ATRP initiator (SiO2@Br) for polymer grafting. CAP was used as the template molecule for imprinting via precipitation polymerization. The effects of varying polymerization reaction parameters, such as template to functional monomer molar ratio (1:2 – 1:10), template to cross-linker molar ratio (1:4 – 1:20), solvent types (acetonitrile and toluene) and their mixtures (0 – 100%), catalyst to ligand ratio (1:2 – 1:10), catalyst to reducing agent ratio (1:2 – 1:10), reaction temperature (313 – 353 K), and reaction time (6 – 30 h) on imprinting factor (IF) values and adsorption capacities (Qt) were studied. The physical and chemical properties of the resulting adsorbent were analyzed using FTIR, TGA, EDX, SEM, HRTEM, and nitrogen sorption techniques. The SiO2@Br had a specific surface area of 638.31 m².g-1 and a total pore volume of 0.4152 cm³.g-1. Post-polymerization, the specific surface area and pore volume of the adsorbent (SiO2@MIPs-CAPcr) decreased to 11.91 m².g-1 and 0.019 cm³.g-1, indicating successful grafting. Adsorption performance was investigated through batch and fixed-bed column studies. Batch experiments investigated the effects of initial solute concentration (10 – 50 mg.L-1), adsorbent dosage (5 – 25 mg), temperature (293 – 313 K), and initial pH (3 – 11) on CAP adsorption. The adsorption equilibrium data for SiO2@MIPs-CAPcr were well fitted by the Sips models, with a maximum adsorption capacity (Qs) of 19.68 mg.g-1. The adsorption kinetic followed pseudo second-order behaviour. Thermodynamic analysis indicated an exothermic process with entropy change due to reduced molecule movement. Selectivity studies involved antibiotics ciprofloxacin (CIP) and thiamphenicol (TAP) as model adsorbates. Fixed-bed column experiments tested initial concentrations (10 – 50 mg.L-1), volumetric inlet flow rates (0.1 – 0.5 mL.min-1), and bed heights (0.5 – 1.0 cm). The Thomas model best described the fixed-bed column adsorption behaviour. The SiO2@MIPs-CAPcr adsorbent demonstrated remarkable selectivity for CAP and excellent adsorption capabilities in both batch and fixed-bed operations.
- PublicationFuzzy-based vector control system for permanent magnet synchronous motor(2024-12-01)Permanent Magnet Synchronous Motor (PMSM) is highly regarded for its efficiency, power density, and dynamic performance, making it integral in industrial automation and electric vehicles. However, traditional PI controllers often struggle with parameter variations, nonlinear characteristics, and load disturbances, affecting steady-state and dynamic performance. This thesis addresses these challenges by proposing a Fuzzy PI control strategy that combines Field-Oriented Control (FOC) with Fuzzy logic, enabling adaptive adjustments of PI parameters for enhanced stability, robustness, and responsiveness. MATLAB/Simulink simulations show that the Fuzzy PI controller achieves faster steady-state response, reduces steady-state error, and minimizes overshoot across various speeds, including 500 and 1200 r/min. During a load disturbance test with a drop from 50% (5 Nm) to zero at 2.5 seconds, both controllers reached a similar overshoot peak (about 600 rpm); however, the Fuzzy PI controller stabilized back to 500 rpm within 0.3 seconds, significantly faster than the 0.8 seconds of the conventional PI controller. Additionally, the Fuzzy PI controller reduced current oscillations (±4 A versus ±6 A), further affirming its superior dynamic response and precision. These results validate the Fuzzy PI control strategy's effectiveness in optimizing PMSM performance, offering a robust framework for advanced control applications.
- PublicationCopper oxide nanocrystals based electrospun nanofibrous membrane for solar water evaporation(2024-03-01)Solar water evaporation has attracted widespread research, which narrowed the huge gap between inadequate clean water supply and human needs. For membrane evaporators, improving the solar absorption, water supply ability, and thermal management are critical to photothermal performance. Developing a suitable structure of light absorbing material could be a feasible approach to address these problems and to enhance evaporation performance. Yet there is limited research focus on this topic. In this study, three different structural CuO-based membrane evaporators were developed to adjust the membrane properties for improving solar evaporation performance. First of all, a triple-layer P/CuO-nanocluster nanofibrous membrane was fabricated through electrospinning, heating and hydrothermal processes. The top and bottom hydrophilic layers of CuO-nanocluster can effectively absorb sunlight, transport water, and suppress salt accumulation on the membrane surface. The middle layer of nanofibrous PVDF-HFP thin-film can support the whole system. The resultant membrane showed an evaporation rate of 1.21 kgm−2h−1 and efficiency of 83.57% for 3.5 wt.% saline water, which is higher than control group without membrane of 0.24 kgm−2h−1 and 16.26%, respectively. The next membrane structure design was core-shell structural P/CuO-Ag NPs nanofibrous membrane. During the electrospinning process, hydrophilic PVP was introduced to help more CuO growth media penetrating into the membrane interior during hydrothermal process. The Ag NPs incorporation enhanced membrane light absorption and wettability. The resultant core-shell P/CuO-Ag membrane achieved better evaporation rates of 1.31 kgm−2h−1 and efficiency of 90.77% for 3.5 wt.% saline water. The final membrane structure was hollow structural P/CuO-C nanofibrous membrane synthesized through coaxial electrospinning. During the fabrication process, the spinning precursor mixed with C NPs in the shell layer to enhance the light absorption while the hydrophilic PVP in the core layer was removed in the hydrothermal step to form a hollow structure. The formation of the hollow structure not only enhanced light absorption but also improved thermal management capacity of the membrane. As a result, the hollow structural P/CuO-C membrane achieved the best evaporation rate of 1.36 kgm−2h−1 and efficiency of 93.07% for 3.5 wt.% saline water as compared to the previous two structures. The outcome of this work will inspire subsequent research to construct of suitable architecture materials for potential applications in water treatment, thermal insulation, energy generation, energy storage, and other related fields.
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- PublicationDesign of a retrofit inferarm cruthes(2008-04-01)The walking stick is a great aid when the person had an accident and his walking is impaired. It provides steadiness and stability, allowing the user to get around pretty well. By the way, for a person that unable to walk, the easiest way to help them to get around is using a wheelchair. It would help them hanging around easily with no burden to walk. But, wheelchair is not able to use in all aspect. For example, the user can't use the wheelchair to go up the staircase. Furthermore, if a person always sits on the wheelchair s without exercise, the bones of legs will get weaker. The main objective of this project is to design a crutch that can assist the disable or leg's injury person to climb up the staircase. It would help to prevent further damage or accidents when the user climbs up the staircase. Besides, the user is able to maintain proper posture, relieves damaging. stress, and reduces the overall chance of injury when climbing staircase. The project has completed with 3D solid modeling of the designed crutches with SolidWork 2007. Furthermore. COSMOS analysis was done on the critical parts of the designed crutches to make sure the factor of safety required was achieved.
- PublicationEvaluation of captopril and nefediplne in Treatment of hypertension secondary to Post streptococcal acute Glomerulonephritis - A randomized control trial.(2012)Post-streptococcal Acute Glomerulonephritis (PSAGN) is still common in Malaysia. Hypertension is one of its main complications which can lead to severe morbidity in children. Conventional method in treating hypertension in these patients was to use nifedipine to reduce the blood pressure. Recent study in the pathophysiology of the disease had shown apart from water and sodium retention, inappropriate production of angiotensin II could also contributes to the development of hypertension. Captopril, an angiotensin converting enzyme inhibitor can help to reduce the production of angiotensin II which can cause blood pressure reduction. To compare the effectiveness of captopril versus nifedipine in controlling blood pressure in children with PSAGN with hypertension. This was a double blinded randomized controlled trial, registered with ANZCTR (Trial No: ACTRN12611000778987) All children admitted to Wad 6 Selatan HUSM diagnosed clinically with PSAGN with hypertension during a one year study period are eligible for the study. Subjects were randomized either to receive nifedipine (control) or captopril (intervention). Outcomes measured are blood pressure changed in the first 4 hours and blood pressure changes until Day 3 of starting the medication, duration of days to achieve blood pressure control, total duration of admission and the need to use additional medication. Blood urea and serum creatinine levels are compared from before starting treatment and at Day 3 after starting treatment. Out of 40 patients who were recruited and randomized, only 19 from the nifedipine treatment group and 13 from the captopril treatment group completed the study. Both treatment groups had no difference in their baseline data. Nifedipine produces a more significant reduction in SBP and DBP compared to captopril in the first 4 hours of starting treatment (SBP p= 0.001, DBP — 0.016). There was no difference in reduction of SBP and DBP after 8 hours of treatment between the groups (SBP p=0.630, DBP p=0.497). There were no significant differences in the duration of blood pressure normalization (nifedipine: 2.7 days, captopril 2.9 days, p= 0.803) and duration of admission (nifedipine: 6.9 days, captopril: 5.4 days; p=0.183) and the need for additional medication to control the blood pressure (p=0.32) between the groups. Changes of blood urea and serum creatinine levels were not significant before and after treatment (Blood urea changes, /?= 0.564; serum creatinine changes, p- 0.236). Nifedipine produces more significant blood pressure reduction in SBP and DBP in the first 4 hours of starting treatment.
- PublicationDiet quality and predictor factors of body weight status among children with learning disabilities in Kelantan(2022-08)Evidence suggests that children with Learning Disabilities (LD) have unhealthy Body Weight Status (BWS) and poor dietary patterns. A cross-sectional study was conducted to determine the diet quality and the predictors of Body Mass Index (BMI) of LD children. This study recruited LD children who attended the Special Education Integration Program from nine schools located in districts with high, moderate and low socio-economic status in Kelantan. Parents completed a Malay language self-administered questionnaire on demographic and socio-economic background, child’s feeding problems, food frequency questionnaire and comprehensive parental feeding practices. Height and weight of children were measured by researcher to determine BWS. Diet quality was assessed using The Malaysian Healthy Eating Index. Multiple linear regression analysis was applied to test the research hypothesis. A total of 259 children with LD aged 10.54±1.69 years (68.0% males, 32.0% females) participated in this study. Their average BMI was 18.38±4.79 kg/m2; males (18.79±4.76 kg/m2) had significantly higher BMI than females (17.52±4.77 kg/m2), p= 0.046. The prevalence of underweight, thin and severely thin were 11.9%, while 28.1% were overweight and obese. The diet quality average score was 48.15±9.23%, where 40.5% of the children were at risk of poor diet quality. The total daily energy intake was 1831.96±542.15 kcal with a mean carbohydrate intake (241.80±74.75g), protein intake (76.10±25.54g) and fat intake (63.42±21.33g), respectively. Majority of children had a higher score for the occurrence of rapid eating (2.00±1.32), food refusal (1.47±1.35), and food selectivity (1.26±1.13) during mealtimes in the past six months. Parental feeding practice including pressure to eat (Beta =-0.282), restriction of weight control (Beta =0.351) and modelling (Beta =-0.162), child age (Beta =0.222), and childbirth weight (Beta =0.137) were significantly related to BMI (R=0.561, R2=0.315; F(5,217) =19.972, p<0.001). The current findings suggested that early detection of nutrition issues in children with LD and regular positive feeding practice by parents during mealtime is essential to address the poor nutritional status of LD children.
- PublicationAir flow in an air conditioning car(2002-03-01)It is necessary for cars in Malaysia to have air-conditioning due to its environment and weather. Basically, this final year project covers the analysis of airconditioning in a model of general shape cabin of a car. For this computer assisted analysis, it involves computation of airflow in the cabin from different sources of airflow positions. The title of my project is “ Airflow In An Air-Conditioning Car”. The analysis was carried out in a standard basic shape of car cabin design which is available in Malaysia. Analysis was in three dimensional (3D) case.
- PublicationModelling and simulation of bio-oil production from palm oil biomass via fast pyrolysis using aspen plus(2021-07-01)The increase in energy consumption, limited fuel resources, massive dependency on fossil fuels, and greenhouse gas emission has resulted in increased research development on renewable energy sources. Renewable energy is the best option for meeting the current energy demands and reduce the dependence on fossil fuels. In this final year project, three palm oil biomass, namely empty fruit bunches (EFB), mesocarp fibre (MF), and palm kernel shell (PKS) were optimized to produce bio-oil via fast pyrolysis. Process modelling and simulation were carried out using ASPEN PLUS V10.0. The simulation includes pre-treatment, fast pyrolysis section, gas-solid separation, and bio-oil refining section. The model developed was successfully validated with the experimental data obtained from literature. Then, the effect of pyrolysis temperature and residence time during the fast pyrolysis of oil palm biomass were studied to maximize the yield of bio-oil product. Based on the results, the maximum bio-oil yields for EFB, MF, and PKS were 56.46 wt.%, 47.39 wt.%, and 44.03 wt.%, respectively, obtained at a temperature of 550 °C and residence time of 2 s. PKS achieved the highest biochar and gas yield of 49.77 wt.% and 37.21 wt.% at 450 °C and 600 °C, respectively due to its highlignin content. The obtained yields in this study are consistent with experimental results found in the literatures. Therefore, the model developed can be used to optimize fast pyrolysis process for different biomass sources without the need to perform complex experimental investigations. Such model will make an important contribution on the improvement and intensification of fast pyrolysis of biomass.