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Displaying publications 41 - 60 of 73 in total

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Hematological values in pregnancy in Orang Asli (aboriginal) women

Ong HC

Med J Malaysia, 1973 Jun;27(4):240-2.
PMID: 4270778
The ovaries at abdominal hysterectomy-conservation or removal?

Ong HC

Med J Malaysia, 1975 Sep;30(1):48-51.
PMID: 1207532
Obstetrical data in Malaysian aborigine women

Ong HC

Trop Geogr Med, 1974 Dec;26(4):384-8.
PMID: 4456697
An unusual case to pentastomiasis of the fallopian tube in an Aborigine woman

Ong HC

J Trop Med Hyg, 1974 Aug;77(8):187-9.
PMID: 4422640
In vitro antidermatophytic activity and cytotoxicity of extracts derived from medicinal plants and marine algae

Sit NW, Chan YS, Lai SC, Lim LN, Looi GT, Tay PL, et al.

J Mycol Med, 2018 Sep;28(3):561-567.
PMID: 30060991 DOI: 10.1016/j.mycmed.2018.07.001

OBJECTIVES: This study was conducted to evaluate the antidermatophytic activity of 48 extracts obtained from medicinal plants (Cibotium barometz, Melastoma malabathricum, Meuhlenbeckia platyclada, Rhapis excelsa, Syzygium myrtifolium, Vernonia amygdalina) and marine algae (Caulerpa sertularioides, Kappaphycus alvarezii) against Trichophyton rubrum and Trichophyton interdigitale (ATCC reference strains), and the cytotoxicity using African monkey kidney epithelial (Vero) cells. Active plant extracts were screened for the presence of phytochemicals and tested against clinical isolates of Trichophyton tonsurans.
METHODS: Six different extracts (hexane, chloroform, ethyl acetate, ethanol, methanol and water) were obtained from each plant or algae sample using sequential solvent extraction. The antidermatophytic activity for the extracts was assessed using a colourimetric broth microdilution method. The viability of Vero cells was measured by Neutral Red uptake assay.
RESULTS: All the extracts (except the water extracts of V. amygdalina, C. sertularioides and K. alvarezii) showed antidermatophytic activity against Trichophyton spp. The minimum fungicidal concentration (MFC) ranges for the plant extracts against T. rubrum and T. interdigitale are 0.0025-2.50 and 0.005-2.50mg/mL, respectively. The algae extracts exhibited lower potency against both species, showing MFC ranges of 0.08-2.50 and 0.31-2.50mg/mL, respectively. The ethanol and methanol extracts from the leaves of R. excelsa, and the methanol and water extracts from the leaves of S. myrtifolium were highly active (MFC<0.1mg/mL) and with high selectivity indices (SI>2.8) against reference strains of T. rubrum and T. interdigitale, and most of the clinical isolates of T. tonsurans. Phytochemical analysis indicates the presence of alkaloids, anthraquinones, flavonoids, saponins, tannins, phenolics and triterpenoids in the extracts.
CONCLUSIONS: The medicinal plant extracts exhibited stronger antidermatophytic activity compared to the algae extracts. The leaves of R. excelsa and S. myrtifolium are potential sources of new antidermatophytic agents against Trichophyton spp.
Predictions of biochar production and torrefaction performance from sugarcane bagasse using interpolation and regression analysis

Chen WH, Hsu HJ, Kumar G, Budzianowski WM, Ong HC

Bioresour Technol, 2017 Dec;246:12-19.
PMID: 28803060 DOI: 10.1016/j.biortech.2017.07.184

This study focuses on the biochar formation and torrefaction performance of sugarcane bagasse, and they are predicted using the bilinear interpolation (BLI), inverse distance weighting (IDW) interpolation, and regression analysis. It is found that the biomass torrefied at 275°C for 60min or at 300°C for 30min or longer is appropriate to produce biochar as alternative fuel to coal with low carbon footprint, but the energy yield from the torrefaction at 300°C is too low. From the biochar yield, enhancement factor of HHV, and energy yield, the results suggest that the three methods are all feasible for predicting the performance, especially for the enhancement factor. The power parameter of unity in the IDW method provides the best predictions and the error is below 5%. The second order in regression analysis gives a more reasonable approach than the first order, and is recommended for the predictions.
Fulltext Gender differences and psychological factors associated with suicidal ideation among youth in Malaysia

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.
Sustainable approach in phlorotannin recovery from macroalgae

Chia SR, Show PL, Phang SM, Ling TC, Ong HC

J Biosci Bioeng, 2018 Aug;126(2):220-225.
PMID: 29673988 DOI: 10.1016/j.jbiosc.2018.02.015

In this present study, alcohol/salt liquid biphasic system was used to extract phlorotannin from brown macroalgae. Liquid biphasic system is a new green technology that integrated with various processes into one-step, by concentrating, separating and purifying the bioproduct in a unit operation. The solvent used is non-toxic and there is potential for solvent recovery which is beneficial to the environment. Phlorotannin is a bioactive compound that has gained much attention due to its health beneficial effect. Therefore, the isolation of phlorotannin is lucrative as it contains various biological activities that are capable to be utilised into food and pharmaceutical application. By using 2-propanol/ammonium sulphate system, the highest recovery of phlorotannin was 76.1% and 91.67% with purification factor of 2.49 and 1.59 from Padina australis and Sargassum binderi, respectively. A recycling study was performed and the salt phase of system was recycled where maximum salt recovery of 41.04% and 72.39% could be obtained from systems containing P. australis and S. binderi, respectively. Similar recovery of phlorotannin was observed after performing two cycles of the system, this concludes that the system has good recyclability and eco-friendly.
Perspectives on cultivation and harvesting technologies of microalgae, towards environmental sustainability and life cycle analysis

Soudagar MEM, Kiong TS, Jathar L, Nik Ghazali NN, Ramesh S, Awasarmol U, et al.

Chemosphere, 2024 Apr;353:141540.
PMID: 38423144 DOI: 10.1016/j.chemosphere.2024.141540

The development of algae is seen as a potential and ecologically sound approach to address the increasing demands in multiple sectors. However, successful implementation of processes is highly dependent on effective growing and harvesting methods. The present study provides a complete examination of contemporary techniques employed in the production and harvesting of algae, with a particular emphasis on their sustainability. The review begins by examining several culture strategies, encompassing open ponds, closed photobioreactors, and raceway ponds. The analysis of each method is conducted in a systematic manner, with a particular focus on highlighting their advantages, limitations, and potential for expansion. This approach ensures that the conversation is in line with the objectives of sustainability. Moreover, this study explores essential elements of algae harvesting, including the processes of cell separation, dewatering, and biomass extraction. Traditional methods such as centrifugation, filtration, and sedimentation are examined in conjunction with novel, environmentally concerned strategies including flocculation, electro-coagulation, and membrane filtration. It evaluates the impacts on the environment that are caused by the cultivation process, including the usage of water and land, the use of energy, the production of carbon dioxide, and the runoff of nutrients. Furthermore, this study presents a thorough examination of the current body of research pertaining to Life Cycle Analysis (LCA) studies, presenting a perspective that emphasizes sustainability in the context of algae harvesting systems. In conclusion, the analysis ends up with an examination ahead at potential areas for future study in the cultivation and harvesting of algae. This review is an essential guide for scientists, policymakers, and industry experts associated with the advancement and implementation of algae-based technologies.
Fulltext Pattern of heart disease and pregnancy seen in a Malaysian hospital

Ong HC, Puraviappan AP, Sinnathuray TA, Chong CH, Sen DK

Singapore Med J, 1978 Jun;19(2):93-7.
PMID: 751193

Pregnancy was associated with cardiac disease in 0.94% of pregnancies. 0.66% with rheumatic lesions and 0.25'\'0 with congenital lesions. The Malays had a higher incidence than the Chinese and Indians. Most of the cardiac pregnancies were in patients between 20-30 years of age and gravida 1 to 4. Nevertheless. still about 30% of cardiac pregnancies were in patients 30 years and over in age and 20% in patient gravida 5 and above. Rheumatic lesions predominated. involving mainly the mitral valve. of which the major lesion was mitral stenosis. PDA. ASD and VSD were the major congenital lesions. Major antepartum matemal complications included arrhythmias. heart failure, anemia and pre-eclampsia. Of the arrhythmias. atrial fibrillation and sinus tachycardia occurred most commonly. A high incidence of prophylactic forceps and vacuum deliveries
was evident. There was one matemal death. The majority of infants were bom alive and well.
Valorization of sorghum distillery residue to produce bioethanol for pollution mitigation and circular economy

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.
Extraction of natural astaxanthin from Haematococcus pluvialis using liquid biphasic flotation system

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.
Fulltext Effects of acids pre-treatment on the microbial fermentation process for bioethanol production from microalgae

Phwan CK, Chew KW, Sebayang AH, Ong HC, Ling TC, Malek MA, et al.

Biotechnol Biofuels, 2019;12:191.
PMID: 31384298 DOI: 10.1186/s13068-019-1533-5

Background: Microalgae are one of the promising feedstock that consists of high carbohydrate content which can be converted into bioethanol. Pre-treatment is one of the critical steps required to release fermentable sugars to be used in the microbial fermentation process. In this study, the reducing sugar concentration of Chlorella species was investigated by pre-treating the biomass with dilute sulfuric acid and acetic acid at different concentrations 1%, 3%, 5%, 7%, and 9% (v/v).
Results: 3,5-Dinitrosalicylic acid (DNS) method, FTIR, and GC-FID were employed to evaluate the reducing sugar concentration, functional groups of alcohol bonds and concentration of bioethanol, respectively. The two-way ANOVA results (p
Source, distribution and emerging threat of micro- and nanoplastics to marine organism and human health: Socio-economic impact and management strategies

Mofijur M, Ahmed SF, Rahman SMA, Arafat Siddiki SY, Islam ABMS, Shahabuddin M, et al.

Environ Res, 2021 04;195:110857.
PMID: 33581088 DOI: 10.1016/j.envres.2021.110857

The nature of micro- and nanoplastics and their harmful consequences has drawn significant attention in recent years in the context of environmental protection. Therefore, this paper aims to provide an overview of the existing literature related to this evolving subject, focusing on the documented human health and marine environment impacts of micro- and nanoplastics and including a discussion of the economic challenges and strategies to mitigate this waste problem. The study highlights the micro- and nanoplastics distribution across various trophic levels of the food web, and in different organs in infected animals which is possible due to their reduced size and their lightweight, multi-coloured and abundant features. Consequently, micro- and nanoplastics pose significant risks to marine organisms and human health in the form of cytotoxicity, acute reactions, and undesirable immune responses. They affect several sectors including aquaculture, agriculture, fisheries, transportation, industrial sectors, power generation, tourism, and local authorities causing considerable economic losses. This can be minimised by identifying key sources of environmental plastic contamination and educating the public, thus reducing the transfer of micro- and nanoplastics into the environment. Furthermore, the exploitation of the potential of microorganisms, particularly those from marine origins that can degrade plastics, could offer an enhanced and environmentally sound approach to mitigate micro- and nanoplastics pollution.
Recent developments in physical, biological, chemical, and hybrid treatment techniques for removing emerging contaminants from wastewater

Ahmed SF, Mofijur M, Nuzhat S, Chowdhury AT, Rafa N, Uddin MA, et al.

J Hazard Mater, 2021 08 15;416:125912.
PMID: 34492846 DOI: 10.1016/j.jhazmat.2021.125912

Emerging contaminants (ECs) in wastewater have recently attracted the attention of researchers as they pose significant risks to human health and wildlife. This paper presents the state-of-art technologies used to remove ECs from wastewater through a comprehensive review. It also highlights the challenges faced by existing EC removal technologies in wastewater treatment plants and provides future research directions. Many treatment technologies like biological, chemical, and physical approaches have been advanced for removing various ECs. However, currently, no individual technology can effectively remove ECs, whereas hybrid systems have often been found to be more efficient. A hybrid technique of ozonation accompanied by activated carbon was found significantly effective in removing some ECs, particularly pharmaceuticals and pesticides. Despite the lack of extensive research, nanotechnology may be a promising approach as nanomaterial incorporated technologies have shown potential in removing different contaminants from wastewater. Nevertheless, most existing technologies are highly energy and resource-intensive as well as costly to maintain and operate. Besides, most proposed advanced treatment technologies are yet to be evaluated for large-scale practicality. Complemented with techno-economic feasibility studies of the treatment techniques, comprehensive research and development are therefore necessary to achieve a full and effective removal of ECs by wastewater treatment plants.
An evaluation of thermal characteristics of bacterium Actinobacillus succinogenes for energy use and circular bioeconomy

Lin BJ, Chen WH, Lin YY, Chang JS, Farooq A, Singh Y, et al.

Bioresour Technol, 2020 Apr;301:122774.
PMID: 31954973 DOI: 10.1016/j.biortech.2020.122774

The thermal characteristics of Actinobacillus succinogenes (AS) from pyrolysis, torrefaction, and combustion are analyzed to evaluate the potential of this biomass as a renewable fuel. AS pyrolysis can be classified into four stages, and its main decomposition zone is at 200-500 °C. The solid yield of AS after 60 min torrefaction is over 60 wt%, and the torrefaction severity index map indicates that a high torrefaction temperature with a short duration has a more profound influence on its decomposition. The Py-GC/MS analysis of AS suggests that the volatile products from 500 °C pyrolysis are similar to microalgae-derived pyrolysis bio-oils. The combustibility index (S) of AS is 4.07 × 10-7 which is much higher than that of lignite coal (0.39 × 10-7) and bituminous coal (0.18 × 10-7), and close to those of biochar and bio-oil. The obtained results are conducive to the development of microorganisms as fuel to achieve a circular bioeconomy.
A review on the engine performance and exhaust emission characteristics of diesel engines fueled with biodiesel blends

Damanik N, Ong HC, Tong CW, Mahlia TMI, Silitonga AS

Environ Sci Pollut Res Int, 2018 Jun;25(16):15307-15325.
PMID: 29721797 DOI: 10.1007/s11356-018-2098-8

Biodiesels have gained much popularity because they are cleaner alternative fuels and they can be used directly in diesel engines without modifications. In this paper, a brief review of the key studies pertaining to the engine performance and exhaust emission characteristics of diesel engines fueled with biodiesel blends, exhaust aftertreatment systems, and low-temperature combustion technology is presented. In general, most biodiesel blends result in a significant decrease in carbon monoxide and total unburned hydrocarbon emissions. There is also a decrease in carbon monoxide, nitrogen oxide, and total unburned hydrocarbon emissions while the engine performance increases for diesel engines fueled with biodiesels blended with nano-additives. The development of automotive technologies, such as exhaust gas recirculation systems and low-temperature combustion technology, also improves the thermal efficiency of diesel engines and reduces nitrogen oxide and particulate matter emissions.
A case of primary adenocarcinoma of the fallopian tube

Ong HC, Chan WF, Sinnathuray TA

Med J Malaysia, 1978 Mar;32(3):217-9.
PMID: 683046
Haemoglobin H disease and pregnancy in a Malaysian woman

Ong HC, White JC, Sinnathuray TA

Acta Haematol., 1977;58(4):229-33.
PMID: 410224 DOI: 10.1159/000207832

A case of haemoglobin H (HbH) disease associated with pregnancy is presented and discussed in the light of reports in the literature. The variable symptomatology is commented upon, although mild to moderate chronic haemolytic anaemia seems to be a constant feature. The roles of folic acid supplements and of splenectomy; the avoidance of oxidant drugs, and the mode of inheritance in HbH disease are briefly commented upon. Available reports indicate that HbH disease probably has no adverse effect on pregnancy. However, the association of the two conditions is uncommon, and reports are too few, therefore, to allow definite conclusions on the outcome in all instances.
Antifungal and cytotoxic activities of selected medicinal plants from Malaysia

Chan YS, Cheah YH, Chong PZ, Khor HL, Teh WS, Khoo KS, et al.

Pak J Pharm Sci, 2018 Jan;31(1):119-127.
PMID: 29348093

This study was conducted to investigate the antifungal potential and cytotoxicity of selected medicinal plants from Malaysia. The extracts from the stem of Cissus quadrangularis and the leaves of Asplenium nidus, Pereskia bleo, Persicaria odorata and Sauropus androgynus were assayed against six fungi using p-iodonitrotetrazolium-based on colorimetric broth microdilution method. All the plant extracts were found to be fungicidal against at least one type of fungus. The strongest fungicidal activity (minimum fungicidal concentration=0.16 mg/mL) were exhibited by the hexane extract of C. quadrangularis, the hexane, chloroform, ethanol and methanol extracts of P. bleo, the hexane and ethyl acetate extracts of P. odorata, and the water extract of A. nidus. In terms of cytotoxicity on the African monkey kidney epithelial (Vero) cells, the chloroform extract of P. odorata produced the lowest 50% cytotoxic concentration (100.3 ± 4.2 μ g/mL). In contrast, none of the water extracts from the studied plants caused significant toxicity on the cells. The water extract of A. nidus warrants further investigation since it showed the strongest fungicidal activity and the highest total activity (179.22 L/g) against Issatchenkia orientalis, and did not cause any toxicity to the Vero cells.

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