Displaying publications 21 - 40 of 73 in total

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  1. Ong HC, Ibrahim N, Wahab S
    PMID: 27574475 DOI: 10.2147/PRBM.S112129
    Nowadays, family members are gradually taking on the role of full-time caregivers for patients suffering from schizophrenia. The increasing burden and tasks of caretaking can cause them psychological distress such as depression or anxiety. The aim of this study was to measure the correlation between perceived stigma and coping, and psychological distress as well as determine the predictors of psychological distress among the caregivers. Results showed that 31.5% of the caregivers experienced psychological distress. "Community rejection" was found to be positively associated with psychological distress. In case of coping subscales, psychological distress had a positive correlation with substance use, use of emotional support, behavioral disengagement, venting, and self-blame, while it was negatively correlated with "positive reframing". Behavioral disengagement was the best predictor of psychological distress among caregivers of patients with schizophrenia, followed by positive reframing, use of emotional support, self-blame, and venting. Health practitioners can use adaptive coping strategies instead of maladaptive for caregivers to help ease their distress and prevent further deterioration of psychological disorders.
    Study site: Psychiatric Clinic, Hospital Canselor Tuanku Muhriz (Pusat Perubatan Universiti Kebangsaan Malaysia, PPUKM)
    Scales & Questionnaire: Kessler’s K10
    Psychological Distress Scale; Devaluation of Consumer Scale (DCS); Devaluation of Consumer Families Scale (DCFS); Brief COPE
  2. Ibrahim N, Ong HC, Wahab S
    Malays J Med Sci, 2017 May;24(3):83-91.
    PMID: 28814936 MyJurnal DOI: 10.21315/mjms2017.24.3.10
    INTRODUCTION: Caregivers often experience stressful situations while in the midst of the caregiving process. Thus, various methods of coping have been widely applied and studied in previous researches. The aim of this study was to develop a novel questionnaire to assess the coping strategies employed by those who provide care to patients, and to further validate it among caregivers of schizophrenia patients in Malaysia.

    METHODS: This study, which involved the caregivers of schizophrenia patients from a hospital in Kuala Lumpur, Malaysia, was comprised of three parts, namely in-depth interviews, a pilot study, and the validation of the developed questionnaire, known as Caregiver Cope (CgCopeTM).

    RESULTS: Part A originally consisted of eight themes, and it was later modified to seven themes with four items each after discussions with some experts. Part B initially had 28 items derived from the seven themes in Part A, which were then reduced to six components after a factor analysis. Part C of the questionnaire consisted of 19 items, with six components (Distraction, Caring for patient, Venting, Religion, Recreation, and Social support) having a moderate to high reliability ranging from a Cronbach's alpha coefficient of 0.54 to 0.82. A factor analysis showed that the six factors of coping accounted for 62.36% of the total variance.

    CONCLUSION: The CgCOPETM questionnaire is suitable for use among caregivers of schizophrenia patients. There is a need to further validate the instrument among caregivers of other patient populations.

  3. Hamadneh N, Khan WA, Sathasivam S, Ong HC
    PLoS One, 2013;8(5):e66080.
    PMID: 23741525 DOI: 10.1371/journal.pone.0066080
    Particle swarm optimization (PSO) is employed to investigate the overall performance of a pin fin.The following study will examine the effect of governing parameters on overall thermal/fluid performance associated with different fin geometries, including, rectangular plate fins as well as square, circular, and elliptical pin fins. The idea of entropy generation minimization, EGM is employed to combine the effects of thermal resistance and pressure drop within the heat sink. A general dimensionless expression for the entropy generation rate is obtained by considering a control volume around the pin fin including base plate and applying the conservations equations for mass and energy with the entropy balance. Selected fin geometries are examined for the heat transfer, fluid friction, and the minimum entropy generation rate corresponding to different parameters including axis ratio, aspect ratio, and Reynolds number. The results clearly indicate that the preferred fin profile is very dependent on these parameters.
  4. Pang YL, Lim S, Ong HC, Chong WT
    Ultrason Sonochem, 2016 Mar;29:317-27.
    PMID: 26585012 DOI: 10.1016/j.ultsonch.2015.10.003
    In this work, γ-Fe2O3 and TiO2 NTs/γ-Fe2O3 composites with good magnetism and sonocatalytic activity were prepared by a facile polyol method and utilize the principle of isoelectric point method, respectively. The structural and magnetic features of the prepared calcined γ-Fe2O3 and composite catalysts were investigated by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), surface analysis, UV-Vis diffuse reflectance spectra (UV-Vis DRS), vibrating sample magnetometry (VSM) and zeta potential analysis. The effects of calcination temperature on γ-Fe2O3 phase variation, physical properties and sonocatalytic properties were investigated. The porosity, specific surface area, band gap energy and sonocatalytic activity of γ-Fe2O3 were gradually decreased with calcination temperature increased. TiO2 NTs/γ-Fe2O3 with appropriate composition and specific structural features possess synergetic effects such as efficient separation of charge carriers and hydroxyl radicals produced by heterogeneous fenton and fenton-like reactions. This enhanced the sonocatalytic activity for the degradation of Orange G under ultrasonic irradiation. The sonocatalytic reactions obeyed pseudo first-order kinetics. All these information provide insight into the design and development of high-efficiency catalyst for wastewater treatment.
  5. Chai TT, Kwek MT, Ong HC, Wong FC
    Food Chem, 2015 Nov 1;186:26-31.
    PMID: 25976787 DOI: 10.1016/j.foodchem.2014.12.099
    This study aimed to isolate a potent antiglucosidase and antioxidant fraction from Stenochlaena palustris. Extraction was performed with hexane, chloroform, ethyl acetate, methanol, and water. Antiglucosidase, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and ferric reducing antioxidant power (FRAP) assays found methanol extract (ME) to be the most active. Water fraction (WF) of ME was a stronger α-glucosidase inhibitor (EC50 2.9 μg/mL) than quercetin, with weak antiamylase activity. WF was a competitive α-glucosidase inhibitor. DPPH scavenging activity of WF (EC50 7.7 μg/mL) was weaker than quercetin. WF (EC50 364 μg/mL) was a stronger hydrogen peroxide scavenger than gallic acid (EC50 838 μg/mL) and was equally strong as quercetin in scavenging superoxide. WF possessed moderate copper chelating activity. WF was enriched in total phenolics (TP) and hydroxycinnamic acids (THC). TP correlated with antioxidant activity (R(2) > 0.76). Only THC correlated with antiglucosidase activity (R(2) = 0.86). Overall, WF demonstrated concurrent, potent antiglucosidase and antioxidant activities.
  6. Ong HC, Singh H, Ng TK, Chong CH
    Med J Malaysia, 1978 Mar;32(3):212-4.
    PMID: 683044
  7. Tan ST, Ong HC, Chai TT, Wong FC
    Pharmacogn Mag, 2018 04 10;14(54):227-230.
    PMID: 29720836 DOI: 10.4103/pm.pm_282_17
    Background: Medicinal fern species represent a potentially important source for both food and medicinal applications. Previously, two underutilized tropical fern species (Blechnum orientale and Phymatopteris triloba) were reported with cytotoxic activities against selected cancer cell lines. However, the exact mechanism remains elusive.

    Objective: In this paper, we reported the identification of six differentially expressed proteins isolated from cancer cells, following exposure to the cytotoxic fern extracts.

    Materials and Methods: The identities of these cancer proteins were determined by matrix-assisted laser desorption ionization time-of-flight protein sequencing.

    Results: The cancer proteins were identified as follows: elongation factor 1-γ, glyceraldehydes-3-phosphate dehydrogenase, heat shock protein 90-β, heterogeneous nuclear ribonucleoprotein-A2/B1, truncated nucleolar phosphoprotein B23, and tubulin-β chain. To the best of our knowledge, this paper represents the first time these cancer proteins are being reported, following exposure to the aforementioned cytotoxic fern extracts.

    Conclusion: It is hoped that further efforts in this direction could lead to the identification and development of target-specific chemotherapeutic agents.

    SUMMARY: Cytotoxic fern extracts were tested in anti-cancer proteomic works.Six differentially-expressed cancer proteins were identified.Potential anti-cancer protein targets were reported. Abbreviations used: EF: Elongation factor; HRP: Horseradish peroxidase; HSP: Heat shock protein; MALDI: Matrix-assisted laser desorption/ionization.

  8. Ha ZY, Ong HC, Oo CW, Yeong KY
    Curr Alzheimer Res, 2020;17(13):1177-1185.
    PMID: 33602088 DOI: 10.2174/1567205018666210218151228
    BACKGROUND: Benzimidazole is an interesting pharmacophore which has been extensively studied in medicinal chemistry due to its high affinity towards various enzymes and receptors. Its derivatives have been previously shown to possess a wide range of biological activities including anthelmintic, antihypertensive, antiulcer, as well as anticholinesterase activity.

    OBJECTIVE: The objective of this study is to search for more potent benzimidazole-based cholinesterase inhibitors, through the modification of the 1- and 2-positions of the benzimidazole core.

    METHODS: Synthesis of compounds were carried out via a 4-step reaction scheme following a previously reported protocol. Structure-activity relationship of the compounds are established through in vitro cholinesterase assays and in silico docking studies. Furthermore, cytotoxicity and blood brain barrier (BBB) permeability of the compounds were also investigated.

    RESULTS: Among the synthesised compounds, three of them (5IIa, 5IIb, and 5IIc) exhibited potent selective butyrylcholinesterase inhibition at low micromolar level. The compounds did not show any significant cytotoxicity when tested against a panel of human cell lines. Moreover, the most active compound, 5IIc, was highly permeable across the blood brain barrier.

    CONCLUSION: In total 10 benzimidazole derivatives were synthesized and screened for their AChE and BuChE inhibitory activities. Lead compound 5Iic, represents a valuable compound for further development as potential AD therapeutics.

  9. Chee CF, Lee HB, Ong HC, Ho AS
    Chem Biodivers, 2005 Dec;2(12):1648-55.
    PMID: 17191961
    In our screening program for new photosensitizers from the Malaysian biodiversity, we found five pheophorbide-related compounds from the leaves and stems of Aglaonema simplex. Detailed spectroscopic analyses showed that compounds 1-3 and 5 are pheophorbide and hydroxy pheophorbide derivatives of chlorophyll a and b. Compound 4, identified as 15(1)-hydroxypurpurin-7-lactone ethyl methyl diester, was isolated for the first time from the Araceae family. An MTT-based short-term survival assay showed that all five compounds exhibit moderate-to-strong photocytotoxic activities towards human leukemia (HL60) and two oral squamous carcinoma cell lines (HSC-2 and HSC-3). Compounds 4 and 5 showed the strongest photocytotoxicities, with IC(50) values of 0.30-0.41 muM (Table 2). Compounds 1-3 with Et chains at C(17(3)) were less photocytotoxic than the parent pheophorbide a (5).
  10. Su G, Ong HC, Mofijur M, Mahlia TMI, Ok YS
    J Hazard Mater, 2022 Feb 15;424(Pt B):127396.
    PMID: 34673394 DOI: 10.1016/j.jhazmat.2021.127396
    The application of waste oils as pyrolysis feedstocks to produce high-grade biofuels is receiving extensive attention, which will diversify energy supplies and address environmental challenges caused by waste oils treatment and fossil fuel combustion. Waste oils are the optimal raw materials to produce biofuels due to their high hydrogen and volatile matter content. However, traditional disposal methods such as gasification, transesterification, hydrotreating, solvent extraction, and membrane technology are difficult to achieve satisfactory effects owing to shortcomings like enormous energy demand, long process time, high operational cost, and hazardous material pollution. The usage of clean and safe pyrolysis technology can break through the current predicament. The bio-oil produced by the conventional pyrolysis of waste oils has a high yield and HHV with great potential to replace fossil fuel, but contains a high acid value of about 120 mg KOH/g. Nevertheless, the application of CaO and NaOH can significantly decrease the acid value of bio-oil to close to zero. Additionally, the addition of coexisting bifunctional catalyst, SBA-15@MgO@Zn in particular, can simultaneously reduce the acid value and positively influence the yield and quality of bio-oil. Moreover, co-pyrolysis with plastic waste can effectively save energy and time, and improve bio-oil yield and quality. Consequently, this paper presents a critical and comprehensive review of the production of biofuels using conventional and advanced pyrolysis of waste oils.
  11. Ibrahim N, Amit N, Che Din N, Ong HC
    Psychol Res Behav Manag, 2017;10:129-135.
    PMID: 28496374 DOI: 10.2147/PRBM.S125176
    Suicide is a global phenomenon that has been showing an upward trend in recent years. It is the second leading cause of death among youth. Studies on suicidal ideation warrant greater attention, as it leads to suicide attempts and other health risk behaviors. Thus, the objective of this study was to compare gender differences in suicidal ideation and determine the predictors of suicidal ideation among youth. This cross-sectional study was carried out among 232 youths aged between 15 and 25 years from selected urban areas in Malaysia. The results showed that suicidal ideation was higher among male participants compared with female participants. Age was the predictor of suicidal ideation for males, while depression and loss of motivation, as components of hopelessness, were the predictors of suicidal ideation among females. Hence, it is important that professionals conduct early identification tests for suicidality among young people. This will facilitate the early detection of depression and hopelessness, which is important, in order to prevent suicidal behaviors or other problems before these occur.
  12. Ong HC, Lee PYA, Ng TK, Chong CH
    Singapore Med J, 1978 Mar;19(1):33-6.
    PMID: 663681
    A retrospective analysis of 102 cases of hydatidiform moles seen in the Maternity Hospital, Kuala Lumpur, Malaysia, is presented. The incidence was 1 : 669. The tumour was more common In the Malays and in the lower social class patients. No specific age group or parity group was exempted. Vaginal bleeding and amenorrhoea were prominent features. Hyperemesis and abdominal cramps occurred less commonly. The uterine size was larger than dates in 62.7% of patients. Pre-eclampsia complicated 23.5% of the moles and Its severity was inversely related to the uterine size. Spontaneous abortion occurred In 57.8% of patients at a mean gestational period of 19 weeks.

    Study site: Maternity Hospital Kuala
    Lumpur, Malaysia
  13. Silitonga AS, Hassan MH, Ong HC, Kusumo F
    Environ Sci Pollut Res Int, 2017 Nov;24(32):25383-25405.
    PMID: 28932948 DOI: 10.1007/s11356-017-0141-9
    The purpose of this study is to investigate the performance, emission and combustion characteristics of a four-cylinder common-rail turbocharged diesel engine fuelled with Jatropha curcas biodiesel-diesel blends. A kernel-based extreme learning machine (KELM) model is developed in this study using MATLAB software in order to predict the performance, combustion and emission characteristics of the engine. To acquire the data for training and testing the KELM model, the engine speed was selected as the input parameter, whereas the performance, exhaust emissions and combustion characteristics were chosen as the output parameters of the KELM model. The performance, emissions and combustion characteristics predicted by the KELM model were validated by comparing the predicted data with the experimental data. The results show that the coefficient of determination of the parameters is within a range of 0.9805-0.9991 for both the KELM model and the experimental data. The mean absolute percentage error is within a range of 0.1259-2.3838. This study shows that KELM modelling is a useful technique in biodiesel production since it facilitates scientists and researchers to predict the performance, exhaust emissions and combustion characteristics of internal combustion engines with high accuracy.
  14. Ooh KF, Ong HC, Wong FC, Sit NW, Chai TT
    Pharmacogn Mag, 2014 Aug;10(Suppl 3):S443-55.
    PMID: 25298659 DOI: 10.4103/0973-1296.139767
    The phytochemistry and bioactivity of wetland macrophytes are underexplored. Plants are known as the natural sources of phytochemical beneficial to health.
  15. Ganandran GS, Mahlia TM, Ong HC, Rismanchi B, Chong WT
    ScientificWorldJournal, 2014;2014:745894.
    PMID: 25133258 DOI: 10.1155/2014/745894
    This paper reports the result of an investigation on the potential energy saving of the lighting systems at selected buildings of the Universiti Tenaga Nasional. The scope of this project includes evaluation of the lighting system in the Library, Admin Building, College of Engineering, College of Information Technology, Apartments, and COE Food court of the university. The main objectives of this project are to design the proper retrofit scenario and to calculate the potential electricity saving, the payback period, and the potential environmental benefits. In this survey the policy for retrofitting the old lighting system with the new energy saving LEDs starts with 10% for the first year and continues constantly for 10 years until all the lighting systems have been replaced. The result of the life cycle analysis reveals that after four years, the selected buildings will bring profit for the investment.
  16. Hasan SS, Teh KM, Ahmed SI, Chong DW, Ong HC, Naina B
    Public Health, 2015 Jul;129(7):954-62.
    PMID: 26138018 DOI: 10.1016/j.puhe.2015.05.014
    OBJECTIVES: To investigate association between quality of life (QoL) and International Normalized Ratio (INR) control, with the secondary aim of assessing QoL using generic and anticoagulation-specific, the Short Form Health Survey (SF-12) and the Duke Anticoagulation Satisfaction Scale (DASS).
    STUDY DESIGN: This study assessed anticoagulation related QoL at three time intervals in two groups of patients on long-term warfarin therapy.
    METHODS: Data of 326 randomly sampled patients (163 patients each in DASS and SF-12 groups) who had been on warfarin therapy for at least one year at anticoagulation clinics were analysed. QoL was assessed at three time intervals: at the start, six months and one year of warfarin therapy. Indications and target INR ranges and subjects INR values were recorded. Time in Therapeutic Range (TTR) was estimated for four subject subgroups, based on target ranges of INR for clustered indications.
    RESULTS: Of the total, 43% of the subjects were aged between 50 and 64 years, and 51% were female. DASS assessed subjects older than 35 years perceived significant decrease in overall mean scores of anticoagulation related QoL, whilst all SF-12 assessed subjects perceived an increase in QoL. The mean percentage days in range for all INR target range subgroups did not exceed more than 60% but there was only a weak correlation (Rs = 0.104, P > 0.05) between INR control and overall QoL.
    CONCLUSION: Malaysian urban outpatients on warfarin treatment longer than one year report a significant overall decrease in QoL, as measured using a validated condition-specific instrument. These patients appeared to adapt well to lifestyle limitations imposed by long-term anticoagulation.
    KEYWORDS: Anticoagulation therapy; International Normalized Ratio; Quality of life

    Study site: anticoagulation clinics at a
    suburban tertiary Ministry of Health hospital in Peninsular
    Malaysia
  17. Yong AL, Ooh KF, Ong HC, Chai TT, Wong FC
    Food Chem, 2015 Nov 1;186:32-6.
    PMID: 25976788 DOI: 10.1016/j.foodchem.2014.11.103
    In this paper, we investigated the antibacterial mechanism and potential therapeutic targets of three antibacterial medicinal plants. Upon treatment with the plant extracts, bacterial proteins were extracted and resolved using denaturing gel electrophoresis. Differentially-expressed bacterial proteins were excised from the gels and subjected to sequence analysis by MALDI TOF-TOF mass spectrometry. From our study, seven differentially expressed bacterial proteins (triacylglycerol lipase, N-acetylmuramoyl-L-alanine amidase, flagellin, outer membrane protein A, stringent starvation protein A, 30S ribosomal protein s1 and 60 kDa chaperonin) were identified. Additionally, scanning electron microscope study indicated morphological damages induced on bacterial cell surfaces. To the best of our knowledge, this represents the first time these bacterial proteins are being reported, following treatments with the antibacterial plant extracts. Further studies in this direction could lead to the detailed understanding of their inhibition mechanism and discovery of target-specific antibacterial agents.
  18. Khoo KS, Chew KW, Ooi CW, Ong HC, Ling TC, Show PL
    Bioresour Technol, 2019 Oct;290:121794.
    PMID: 31319214 DOI: 10.1016/j.biortech.2019.121794
    This work aimed to study the application of liquid biphasic flotation (LBF) for the efficient and rapid recovery of astaxanthin from H. pluvialis microalgae. The performance of LBF for the extraction of astaxanthin was studied comprehensively under different operating conditions, including types and concentrations of food-grade alcohol and salt, volume ratio, addition of neutral salt, flotation period, and mass of dried H. pluvialis biomass powder. The maximum recovery, extraction efficiency and partition coefficient of astaxanthin obtained from the optimum LBF system were 95.11 ± 1.35%, 99.84 ± 0.05% and 385.16 ± 3.87, respectively. A scaled-up LBF system was also performed, demonstrating the feasibility of extracting natural astaxanthin from microalgae at a larger scale. This exploration of LBF system opens a promising avenue to the extraction of astaxanthin at lower cost and shorter processing time.
  19. Ong HC, Ling AC, Ng DS, Ng RX, Wong PL, Omar SFS
    IDCases, 2021;23:e01051.
    PMID: 33532241 DOI: 10.1016/j.idcr.2021.e01051
    Preterm birth is a global concern with considerable morbidity and mortality. Intrapartum infection is a known cause of preterm birth and Actinomyces infection is one of the infections contributing to preterm birth. We report a case of preterm birth of a trisomy-21 neonate to a mother with positive Actinomyces naeslundii from an intra-operative placental swab sample and discussed the relationship of this bacteria and preterm delivery, and the role of postpartum antibiotics use in this case.
  20. Chen WH, Lo HJ, Yu KL, Ong HC, Sheen HK
    Environ Pollut, 2021 Sep 15;285:117196.
    PMID: 33962308 DOI: 10.1016/j.envpol.2021.117196
    This research aims to study the wet torrefaction (WT) and saccharification of sorghum distillery residue (SDR) towards hydrochar and bioethanol production. The experiments are designed by Box-Behnken design from response surface methodology where the operating conditions include sulfuric acid concentration (0, 0.01, and 0.02 M), amyloglucosidase concentration (36, 51, and 66 IU), and saccharification time (120, 180, and 240 min). Compared to conventional dry torrefaction, the hydrochar yield is between 13.24 and 14.73%, which is much lower than dry torrefaction biochar (yield >50%). The calorific value of the raw SDR is 17.15 MJ/kg, which is significantly enhanced to 22.36-23.37 MJ/kg after WT. When the sulfuric acid concentration increases from 0 to 0.02 M, the glucose concentration in the product increases from 5.59 g/L to 13.05 g/L. The prediction of analysis of variance suggests that the best combination to maximum glucose production is 0.02 M H2SO4, 66 IU enzyme concentration, and 120 min saccharification time, and the glucose concentration is 30.85 g/L. The maximum bioethanol concentration of 19.21 g/L is obtained, which is higher than those from wheat straw (18.1 g/L) and sweet sorghum residue (16.2 g/L). A large amount of SDR is generated in the kaoliang liquor production process, which may cause environmental problems if it is not appropriately treated. This study fulfills SDR valorization for hydrochar and bioenergy to lower environmental pollution and even achieve a circular economy.
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