Displaying publications 21 - 40 of 42 in total

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  1. Ceftazidime-resistant Klebsiella pneumoniae bloodstream infection in children with febrile neutropenia
    Ariffin H, Navaratnam P, Mohamed M, Arasu A, Abdullah WA, Lee CL, et al.
    Int J Infect Dis, 2000;4(1):21-5.
    PMID: 10689210
    OBJECTIVES: To evaluate prevalence of ceftazidime-resistant Klebsiella pneumoniae (CRKP) in the pediatric oncology unit of University Hospital, Kuala, Lumpur, and to identify differences between febrile neutropenic pediatric patients with CRKP and ceftazidime-sensitive K. pneumoniae (CSKP) bacteremia.

    MATERIALS AND METHODS: Febrile neutropenic patients treated between January 1996 and December 1997 at the pediatric oncology unit of University Hospital, Kuala Lumpur, were prospectively studied. Empirical antibiotic therapy consisted of ceftazidime and amikacin. Those who developed K. pneumoniae bacteremia were identified, and clinical features analyzed. Ceftazidime-resistance was documented via disk-diffusion testing. Production of extended-spectrum beta-lactamase (ESBL) was inferred on the basis of synergy between ceftazidime and amoxicillin-clavulanic acid. The different features between the two groups and variables associated with the development of CRKP bacteremia were analyzed using chi-square and t-tests and calculation of odds ratios. A multivariate analysis was used to identify independent factors for CRKP development.

    RESULTS: Ceftazidime-resistance was seen in 51.6% of all K. pneumoniae isolates, and all these isolates were inferred to be ESBL producers. All isolates were sensitive to imipenem. Susceptibility to gentamicin was 90.5%. The mean continuous hospital stay prior to the detection of bacteremia was 13.7 days overall, but significantly longer in the CRKP group (21.9 d) compared to the CSKP group (4.3 d) (P = 0.003). Children with CRKP were more likely to have received antibiotics in the 2 weeks prior to detection of bacteremia (87.5% of cases) than the CSKP group (20.0% of cases) (P = 0.0008). Sepsis-related mortality was higher in those with CRKP (50.0%) than in the CSKP group (13.3%) (P = 0.02). Patients who did not receive CRKP-directed antibiotics within 48 hours of admission were more likely to have a fatal outcome than those who did (P = 0.009). Logistic regression analysis identified use of third-generation cephalosporins 2 weeks prior to presentation and a hospital stay of 2 weeks or more as independent risk factors for development of CRKP.

    CONCLUSIONS: More than half of total K. pneumoniae isolated from blood cultures in the unit were ceftazidime-resistant. Children with febrile neutropenia with prolonged hospital stay and recent prior antibiotic exposure are at high risk of developing CRKP bacteremia. Mortality was significantly higher in this group. Early commencement of appropriate antibiotics (e.g., imipenem with or without gentamicin), according to susceptibility study results, may be beneficial in such circumstances.

  2. Virotherapy: Current Trends and Future Prospects for Treatment of Colon and Rectal Malignancies
    Lee CL, Veeramani S, Molouki A, Lim SHE, Thomas W, Chia SL, et al.
    Cancer Invest, 2019;37(8):393-414.
    PMID: 31502477 DOI: 10.1080/07357907.2019.1660887
    Colorectal cancer (CRC) is one of the most common malignancies. In recent decades, early diagnosis and conventional therapies have resulted in a significant reduction in mortality. However, late stage metastatic disease still has very limited effective treatment options. There is a growing interest in using viruses to help target therapies to tumour sites. In recent years the evolution of immunotherapy has emphasised the importance of directing the immune system to eliminate tumour cells; we aim to give a state-of-the-art over-view of the diverse viruses that have been investigated as potential oncolytic agents for the treatment of CRC.
  3. Fulltext Standardization and experience may influence the survival of laparoscopic radical hysterectomy for cervical cancer
    Lee CL, Huang KG, Chua PT, Mendoza MCVR, Lee PS, Lai SY
    Taiwan J Obstet Gynecol, 2021 May;60(3):463-467.
    PMID: 33966729 DOI: 10.1016/j.tjog.2021.03.013
    OBJECTIVE: Minimally invasive radical hysterectomy has been shown to be associated with poorer outcome in an influential prospective, randomized trial. However, many centers worldwide performing minimally invasive radical hysterectomy have data and experience that prove otherwise. We aim to review surgical and oncologic outcomes of patients operated by Laparoscopic Radical Hysterectomy in a tertiary hospital, by experienced surgeons and standardization in radicality, for cervical carcinoma Stage 1A1-1B1 from January 2009 to May 2014.

    MATERIALS & METHODS: Standardised surgical technique with Parametrium & Paracolpium resection approach was adopted by qualified and experienced Gynecologic/Gyne-Oncologic Endoscopic & Minimally Invasive Surgeons in performing Laparoscopic Radical Hysterectomy for Cervical Cancer stage 1A1-1B1 from January 2009-May 2014, involving 53 patients. Electronic Medical Record system (EMR) Of Chang Gung Memorial Hospital(Tertiary Referral Centre), Department of Obstetrics & Gynecology was accessed for surgical and oncologic outcomes.

    RESULTS: Fifty-Three patients operated from January 2009 to May 2014 were followed up for an average of 96.7 months with longest follow-up at 127 months. There were no cases of recurrence or death reported. 5 Year - Survival Rate and 5 Year Disease-Free Survival Rate were 100%. Two patients received post-operative pelvic radiation concurrent with chemotherapy using Cisplatin due to greater than 1/3 cervical stromal invasion.

    CONCLUSION: It is vital to standardize minimally invasive surgical techniques for early stage cervical cancer, with focus on adequate radicality and resection which may contribute to excellent survival outcomes. Further international multi-center randomized trial (Minimally Invasive Therapy Versus Open Radical Hysterectomy In Cervical Cancer) will provide justification for continued practice of MIS in early stage cervical cancer.

  4. Fulltext Diabetes literacy and knowledge among patients with type 2 diabetes mellitus attending a primary care clinic in Seremban, Malaysia
    Lee CL, Chee WSS, Arasu K, Kwa SK, Mohd Ali SZ
    Malays J Nutr, 2019;25(4):435-444.
    MyJurnal DOI: 10.31246/mjn-2019-0031
    Introduction: Good health literacy and knowledge are associated with improved outcomes in diabetes. The purpose of this study was to determine diabetes-specific literacy and knowledge levels, and its associated socio-demographic factors, among adults with type 2 diabetes mellitus (T2DM).
    Methods: This cross-sectional study was conducted among 196 adults from the Indian, Chinese, and Malay ethnic groups with T2DM who attended a primary care clinic in Seremban, Malaysia. The Literacy Assessment for Diabetes and Diabetes Knowledge Test 2 were used to assess diabetes-specific literacy and knowledge, respectively.
    Results: The majority of participants (75.0%) had literacy scores that corresponded to Ninth Grade Level but only 3.6% of participants had a good knowledge of diabetes. Literacy scores explained up to 19.8% of the variance in knowledge scores (r=0.445, p<0.01). Indian participants had the lowest literacy and knowledge scores when compared to Chinese and Malays (p<0.05). Participants with higher education had better literacy
    and knowledge scores (p<0.05). Educational level was more likely than ethnicity to predict both literacy and knowledge scores (p<0.001), while gender and age did not significantly predict either score. The majority of participants could answer general questions about physical activity, diabetes-related complications and healthy eating. Knowledge of diabetes and its relation to specific foods and the effect of diet on glucose control were limited among the participants.
    Conclusion: Education and ethnicity were associated with literacy and knowledge on diabetes. There existed a deficit of diabetes-related nutrition knowledge among the participants. These findings may help healthcare providers tailor individualised patient educational interventions.
    Keywords: Diabetes literacy, diabetes knowledge, type 2 diabetes
  5. Knowledge, attitudes and practices of schoolchildren toward whole grains and nutritional outcomes in Malaysia
    Koo HC, Lee CL, Nur Hidayah AS, Nurain Hazwani AR
    Appetite, 2018 04 01;123:256-263.
    PMID: 29309853 DOI: 10.1016/j.appet.2018.01.002
    Whole grains play an important role in regulating body weight. However, interventions aimed to increase whole grains consumption have had limited impact on body mass index for age z-score (BAZ) due to insufficient understanding of knowledge, attitudes and practices (KAP) toward whole grains. This survey aimed to evaluate whole grains KAP among schoolchildren, as well as to investigate the associations of whole grains KAP with BAZ among the schoolchildren in Negeri Sembilan, Malaysia. This cross-sectional survey was conducted among 380 schoolchildren aged 9-11 years, cluster sampled from six randomly selected schools. Data were collected through a validated self-administered guided questionnaire. Body weight and height were measured. A majority of the schoolchildren had normal body weight (56.6%), moderate whole grains knowledge (42.6%), as well as neutral attitudes (66.1%) and poor practices (58.9%) toward whole grains consumption. Significant positive associations were found between knowledge and attitudes (r = 0.337; p 
  6. Fulltext Exploring the Biocontrol Efficacy of Trichoderma spp. against Rigidoporus microporus, the Causal Agent of White Root Rot Disease in Rubber Trees (Hevea brasiliensis)
    Go WZ, Chin KL, H'ng PS, Wong MY, Lee CL, Khoo PS
    Plants (Basel), 2023 Feb 27;12(5).
    PMID: 36903926 DOI: 10.3390/plants12051066
    Rigidoporus microporus, which causes white root rot disease (WRD) in Hevea brasiliensis, is a looming threat to rubber plantation in Malaysia. The current study was conducted to determine and evaluate the efficiency of fungal antagonists (Ascomycota) against R. microporus in rubber trees under laboratory and nursery conditions. A total of 35 fungal isolates established from the rubber tree rhizosphere soil were assessed for their antagonism against R. microporus by the dual culture technique. Trichoderma isolates can inhibit the radial growth of R. microporus by 75% or more in the dual culture test. Strains of T. asperellum, T. koningiopsis, T. spirale, and T. reesei were selected to assess the metabolites involved in their antifungal activity. Results indicated that T. asperellum exhibited an inhibitory effect against R. microporus in both volatile and non-volatile metabolite tests. All Trichoderma isolates were then tested for their ability in producing hydrolytic enzymes such as chitinase, cellulase and glucanase, indole acetic acid (IAA), siderophores production, and phosphate solubilization. From the positive results of the biochemical assays, T. asperellum and T. spirale were selected as the biocontrol candidates to be further tested in vivo against R. microporus. The nursery assessments revealed that rubber tree clone RRIM600 pretreated with only T. asperellum or with the combination of T. asperellum and T. spirale was able to reduce the disease severity index (DSI) and exert higher suppression of R. microporus compared to other pretreated samples, with the average DSI below 30%. Collectively, the present study demonstrates that T. asperellum represents a potential biocontrol agent that should be further explored to control R. microporus infection on rubber trees.
  7. Fulltext Physical properties and bonding quality of laminated veneer lumber produced with veneers peeled from small-diameter rubberwood logs
    Khoo PS, Chin KL, H'ng PS, Bakar ES, Lee CL, Go WZ, et al.
    R Soc Open Sci, 2019 Dec;6(12):191763.
    PMID: 31903217 DOI: 10.1098/rsos.191763
    The peeling of small-diameter rubberwood logs from the current short-rotation practices undoubtedly will produce lower grade veneers compared to the veneers from conventional planting rotation. Hence, this raises the question of the properties of the produced laminated veneer lumber (LVL) from veneers peeled from small-diameter rubberwood logs using the spindleless lathe technology. Different thicknesses of rubberwood veneers was peeled from rubberwood logs with diameter less than 20 cm using a spindleless lathe. Three-layer LVLs were prepared using phenol formaldehyde (PF) adhesive and hot pressed at different temperatures. During the peeling of veneer, lathe checks as deep as 30-60% of the veneer thickness are formed. Owing to deeper lathe check on 3 mm rubberwood veneer, higher pressing temperature significantly increased the gluebond shear strength of the PF-bonded LVL. In addition, lathe check frequency was also shown to influence the bond strength. The presence of higher lathe check frequency on 2 mm veneer increased the wettability, thus facilitating optimum penetration of adhesive for stronger bonding. These findings stress the importance of measuring and considering the lathe check depth and frequency during the lamination process to get a better understanding of bonding quality in veneer-based products.
  8. Fulltext Characterization of bioadsorbent produced using incorporated treatment of chemical and carbonization procedures
    Lee CL, H'ng PS, Chin KL, Paridah MT, Rashid U, Go WZ
    R Soc Open Sci, 2019 Sep;6(9):190667.
    PMID: 31598301 DOI: 10.1098/rsos.190667
    The production of bioadsorbent from palm kernel shell (PKS) and coconut shell (CS) pretreated with 30% phosphoric acid (H3PO4) was optimized using the response surface methodology (RSM). Iodine adsorption for both bioadsorbents was optimized by central composite design. Two parameters including the H3PO4 pretreatment temperature and carbonization temperature were determined as significant factors to improve the iodine adsorption of the bioadsorbent. Statistical analysis results divulge that both factors had significant effect on the iodine adsorption for the bioadsorbent. From the RSM analysis, it was suggested that using 80 and 79°C as H3PO4 pretreatment temperature and 714 and 715°C as carbonization temperature would enhance the iodine adsorption of the CS and PKS bioadsobent, respectively. These results indicated that H3PO4 is a good pretreatment for preparing PKS and CS prior to carbonization process to produce bioadsorbent with well-developed microporous and mesoporous volume. The effort to produce alternative high grade and inexpensive adsorbent derived from lignocellulosic biomass, particularly in the nut shell form was implied in this research.
  9. Fulltext Valorisation of Underutilized Grass Fibre (Stem) as a Potential Material for Paper Production
    Lee CL, Chin KL, H'ng PS, Hafizuddin MS, Khoo PS
    Polymers (Basel), 2022 Nov 29;14(23).
    PMID: 36501601 DOI: 10.3390/polym14235203
    An integrated and feasible approach was proposed using the underutilized grass fibre (stem) derived from Napier grass and sugarcane for paper production in this study. To enhance paper strength, pre-hydrolysis and beating techniques have been used to improve the chemical pulps and mechanical pulping process, respectively. Napier grass and sugarcane are promising non-wood sources for pulp production, owing to their high cellulose and low lignin and extractive content. With the additional mild alkaline pre-treatment to the mechanical pulping process, the lignin content was greatly reduced. The results reveal that the mechanical pulping with alkaline pre-treatment may indeed potentially replace the most prevalent pulping process (chemical pulping). As evidenced by the paper strength properties, mechanical pulping is far more suitable for grass-type biomass, particularly Napier grass, which had a folding endurance capability five times greater than chemical pulping. Furthermore, the remaining high hemicellulose content from mechanical pulping contributed to a high pulp yield, while also facilitating the fibrillation on the sugarcane's laboratory paper handsheet. The findings also demonstrated that the additional beating process from chemical pulping causes the fibres to be drawn toward each other, resulting in a more robust fibre network that contributes to good paper strength. Consequently, this work sheds new light on the development of advanced paper derived from grass fibre.
  10. Fulltext Fabrication of Highly Microporous Structure Activated Carbon via Surface Modification with Sodium Hydroxide
    Hafizuddin MS, Lee CL, Chin KL, H'ng PS, Khoo PS, Rashid U
    Polymers (Basel), 2021 Nov 16;13(22).
    PMID: 34833252 DOI: 10.3390/polym13223954
    The aim of this study was to select the optimal conditions for the carbonization process followed by surface modification treatment with sodium hydroxide (NaOH) to obtain a highly microporous activated carbon structure derived from palm kernel shells (PKS) and coconut shells (CS). The effects of the carbonization temperature and NaOH concentration on the physiochemical properties, adsorption capability, specific surface area, surface morphology, and surface chemistry of PKS and CS were evaluated in this study. The results show that surface-modified activated carbons presented higher surface area values (CS: 356.87 m2 g-1, PKS: 427.64 m2 g-1), smaller pore size (CS: 2.24 nm, PKS: 1.99 nm), and larger pore volume (CS: 0.34 cm3 g-1, PKS: 0.30 cm3 g-1) than the untreated activated carbon, demonstrating that the NaOH surface modification was efficient enough to improve the surface characteristics of the activated carbon. Moreover, surface modification via 25% NaOH greatly increases the active functional group of activated carbon, thereby directly increasing the adsorption capability of activated carbon (CS: 527.44 mg g-1, PKS: 627.03 mg g-1). By applying the NaOH post-treatment as the ultimate surface modification technique to the activated carbon derived from PKS and CS, a highly microporous structure was produced.
  11. Fulltext Application strategies by selective medium treated with entomopathogenic bacteria Serratia marcescens and Pseudomonas aeruginosa as potential biocontrol against Coptotermes curvignathus
    Chin KL, H'ng PS, Lee CL, Wong WZ, Go WZ, Khoo PS, et al.
    R Soc Open Sci, 2021 Apr 14;8(4):201311.
    PMID: 33996113 DOI: 10.1098/rsos.201311
    The success of microbial termiticides in controlling termites depends on the ability of microbes to grow in different media and the functionality of the microbes as a resistant barrier or toxic bait. This study was conducted to understand the mortality rate and behaviour changes of the subterranean termite Coptotermes curvignathus Holmgren introduced with different concentrations of Serratia marcescens strain LGMS 1 and Pseudomonas aeruginosa strain LGMS 3 using wood and soil as bacterial transfer medium. In general, higher concentration of bacteria in soil caused a reduction in tunnelling activity and wood consumption and an increase in mortality. However, application on wood revealed a different outcome. Wood treated with S. marcescens of 106 CFU ml-1 concentration proved to be more efficient as bait than higher concentration applications as it caused a high mortality rate while still highly palatable for termites. Wood or soil treated with S. marcescens concentration higher than 109 CFU ml-1 creates a high toxicity and repellent barrier for termites. Pseudomonas aeruginosa of 109 CFU ml-1 concentrations applied on wood served as a slow-acting toxic bait. However, the ability for S. marcescens and P. aeruginosa to survive on wood is low, which made the bait unable to retain a useful level of toxicity for a long period of time and frequent reapplication is needed.
  12. Microwave steam activation, an innovative pyrolysis approach to convert waste palm shell into highly microporous activated carbon
    Yek PNY, Liew RK, Osman MS, Lee CL, Chuah JH, Park YK, et al.
    J Environ Manage, 2019 Apr 15;236:245-253.
    PMID: 30735943 DOI: 10.1016/j.jenvman.2019.01.010
    Microwave-steam activation (MSA), an innovative pyrolysis approach combining the use of microwave heating and steam activation, was investigated for its potential production of high grade activated carbon (AC) from waste palm shell (WPS) for methylene blue removal. MSA was performed via pyrolytic carbonization of WPS to produce biochar as the first step followed by steam activation of the biochar using microwave heating to form AC. Optimum yield and adsorption efficiency of methylene blue were obtained using response surface methodology involving several key process parameters. The resulting AC was characterized for its porous characteristics, surface morphology, proximate analysis and elemental compositions. MSA provided a high activation temperature above 500 °C with short process time of 15 min and rapid heating rate (≤150 °C/min). The results from optimization showed that one gram of AC produced from steam activation under 10 min of microwave heating at 550 °C can remove up to 38.5 mg of methylene blue. The AC showed a high and uniform surface porosity consisting high fixed carbon (73 wt%), micropore and BET surface area of 763.1 and 570.8 m2/g respectively, hence suggesting the great potential of MSA as a promising approach to produce high grade adsorbent for dye removal.
  13. Strategic hazard mitigation of waste furniture boards via pyrolysis: Pyrolysis behavior, mechanisms, and value-added products
    Foong SY, Liew RK, Lee CL, Tan WP, Peng W, Sonne C, et al.
    J Hazard Mater, 2022 01 05;421:126774.
    PMID: 34364214 DOI: 10.1016/j.jhazmat.2021.126774
    Waste furniture boards (WFBs) contain hazardous formaldehyde and volatile organic compounds when left unmanaged or improperly disposed through landfilling and open burning. In this study, pyrolysis was examined as a disposal and recovery approach to convert three types of WFBs (i.e., particleboard, plywood, and fiberboard) into value-added chemicals using thermogravimetric analysis coupled with Fourier-transform infrared spectrometry (TG-FTIR) and pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS). TG-FTIR analysis shows that pyrolysis performed at an optimum temperature of 250-550 °C produced volatile products mainly consisting of carbon dioxide, carbon monoxide, and light hydrocarbons, such as methane. Py-GC/MS shows that pyrolysis at different final temperatures and heating rates recovered mainly phenols (25.9-54.7%) for potential use as additives in gasoline, colorants, and food. The calorific value of WFBs ranged from 16 to 18 MJ/kg but the WFBs showed high H/C (1.7-1.8) and O/C (0.8-1.0) ratios that provide low chemical energy during combustion. This result indicates that WFBs are not recommended to be burned directly as fuel, however, they can be pyrolyzed and converted into solid pyrolytic products such as biochar with improved properties for fuel application. Hazardous components, such as cyclopropylmethanol, were removed and converted into value-added compounds, such as 1,4:3,6-dianhydro-d-glucopyranose, for use in pharmaceuticals. These results show that the pyrolysis of WFBs at high temperature and low heating rate is a promising feature to produce value-added chemicals and reduce the formation of harmful chemical species. Thus, the release of hazardous formaldehyde and greenhouse gases into the environment is redirected.
  14. Fulltext Septicaemia of subterranean termites Coptotermes curvignathus caused by disturbance of bacteria isolated from termite gut and its foraging pathways
    Chin KL, H'ng PS, Wong WZ, Lee CL, Khoo PS, Luqman AC, et al.
    R Soc Open Sci, 2020 Aug;7(8):200847.
    PMID: 32968530 DOI: 10.1098/rsos.200847
    Microbial pathogens continue to attract a great deal of attention to manage the termite population. Every bacterium has its own mode of action and in fact, the mechanisms used by bacteria to attack termites remain elusive at the moment. Hence, the objective of this study was to evaluate the susceptibility of subterranean termites Coptotermes curvignathus to opportunistic pathogens using culturable aerobic bacteria isolated from the termite gut and its foraging pathways. Bacterial suspensions were prepared in concentrations of 103, 106 and 109 colony-forming units (CFU) ml-1 and introduced to the termites via oral-contact and physical contact treatment. The data show that contact method acted slower and gave lower mortality, compared to the oral-contact method. Coptotermes curvignathus were highly susceptible to Serratia marcescens and Pseudomonas aeruginosa. Serratia marcescens showed the highest mortality percentage of 68% and 54% at bacterial concentration of 109 CFU ml-1 via oral-contact and contact method, respectively. Serratia marcescens was also defined as the bacteria with the highest ability to induce the high mortality of C. curvignathus with the lowest concentration of bacterial suspension at a given time under laboratory condition. The results of this study indicate that P. aeruginosa and S. marcescens in particular may be attractive candidates worth further examination as a possible biocontrol agent against C. curvignathus in the field and to evaluate environmental and ecological risks of the biocontrol.
  15. A Review of Bio-Based Activated Carbon Properties Produced from Different Activating Chemicals during Chemicals Activation Process on Biomass and Its Potential for Malaysia
    Chew TW, H'Ng PS, Luqman Chuah Abdullah BCTG, Chin KL, Lee CL, Mohd Nor Hafizuddin BMS, et al.
    Materials (Basel), 2023 Nov 27;16(23).
    PMID: 38068108 DOI: 10.3390/ma16237365
    Activated carbon is the preferred adsorbent for gas and water treatment in various industry across the world due to its efficiency, reliability, and accessibility. Recently, in Malaysia, studies are mainly focused on the fabrication of activated carbon from lignocellulosic biomass-based precursors from agricultural waste such as coconut shell, rice husk, and palm kernel shell. Activated carbon fabrication is a two-step process; the precursor will first undergo carbonization, then, activation is carried out either physically or chemically to develop its porous surface for adsorption purposes. The main benefit of activated carbon is the customizable pore structure for different utilization, which can be easily achieved by the chemical activation process. The types and concentration of chemicals used for activation, pre-treatment of precursor, duration of the activation process, and the mass ratio of precursor to chemicals are proven to effectively influence the resulting pore structure. However, the chemicals used in the activation process can be harmful to the environment. Thus, the chemical recovery process is necessary after the activation process. Nonetheless, more in-depth research on producing activated carbon from abundant biomass materials with bio-based chemical agents for activation is needed to achieve an ecological and sustainable manufacturing process.
  16. Fulltext Virulence of Rigidoporus microporus Isolates Causing White Root Rot Disease on Rubber Trees (Hevea brasiliensis) in Malaysia
    Go WZ, Chin KL, H'ng PS, Wong MY, Luqman CA, Surendran A, et al.
    Plants (Basel), 2021 Oct 07;10(10).
    PMID: 34685932 DOI: 10.3390/plants10102123
    Latex production from Hevea brasiliensis rubber tree is the second most important commodity in Malaysia, but this industry is threatened by the white root rot disease (WRD) caused by Rigidoporus microporus that leads to considerable latex yield loss and tree death. This study aimed to characterize and compare the virulence of five R. microporus isolates obtained from infected rubber trees located at different states in Malaysia. These isolates were subjected to morphological and molecular characterization for species confirmation and pathogenicity test for the determination of virulence level. BLAST search showed that the ITS sequences of all the pathogen isolates were 99% identical to R. microporus isolate SEG (accession number: MG199553) from Malaysia. The pathogenicity test of R. microporus isolates conducted in a nursery with 24 seedlings per isolate showed that isolate RL21 from Sarawak has developed the most severe above- and below-ground symptoms of WRD on the rubber clone RRIM600 as host. Six months after being infected with R. microporus, RL21 was evaluated with the highest average of disease severity index of 80.52% for above- and below-ground symptoms, followed by RL22 (68.65%), RL20 (66.04%), RL26 (54.38%), and RL25 (43.13%). The in vitro growth condition tests showed that isolate RL21 of R. microporus has optimum growth at 25-30 °C, with the preference of weakly acidic to neutral environments (pH 6-7). This study revealed that different virulence levels are possessed among different R. microporus isolates even though they were isolated from the same host species under the same climate region. Taken together, field evaluation through visual observation and laboratory assays have led to screening of the most virulent isolate. Determination of the most virulent isolate in the present study is vital and shall be taken into consideration for the selection of suitable pathogen isolate in the development of more effective control measures in combating tenacious R. microporus.
  17. Fulltext Evolution of Hematopoietic Stem Cell Transplant Programs in Malaysia
    Saidon N, Anuar NA, Meng CK, Chuan OT, Mui TS, Gin GG, et al.
    Blood Cell Ther, 2020 Aug 25;3(3):44-47.
    PMID: 36714175 DOI: 10.31547/bct-2019-017
    Hematopoietic stem cell transplantation (HSCT) is now widely practiced worldwide. It has the potential to cure many hematological diseases, such as acute leukemia and thalassemia. As an emerging country, Malaysia has made advancements despite many challenges. HSCT has evolved rapidly since the first pediatric allogeneic HSCT case in 1987. The first adult HSCT was performed 5 years later in 1993. Currently, a total of 13 hospitals offer HSCT services throughout Malaysia. These include private healthcare services, substantially funded government hospitals governed by the Ministry of Health, and partially funded teaching hospitals governed by the Ministry of Education. Until 2015, 1,987 allogeneic and 1,648 autologous HSCT procedures were performed. This article narrates the history and development of HSCT in Malaysia and briefly discusses the challenging issues in this area.
  18. Fulltext Production of bioadsorbent from phosphoric acid pretreated palm kernel shell and coconut shell by two-stage continuous physical activation via N2 and air
    Lee CL, H'ng PS, Paridah MT, Chin KL, Rashid U, Maminski M, et al.
    R Soc Open Sci, 2018 Dec;5(12):180775.
    PMID: 30662718 DOI: 10.1098/rsos.180775
    In the present study, agricultural biomass-palm kernel shell (PKS) and coconut shell (CS)-was used to produce high porosity bioadsorbent using two-stage continuous physical activation method with different gas carrier (air and N2) in each stage. The activation temperature was set constant at 600, 700, 800 or 900°C for both activation stages with the heating rate of 3°C min-1. Two parameters, the gas carrier and activation temperature, were determined as the significant factors on the adsorption properties of bioadsorbent. BET, SEM, FTIR, TGA, CHNS/O and ash content were used to elucidate the developed bioadsorbent prepared from PKS and CS and its capacity towards the adsorption of methylene blue and iodine. The novel process of two-stage continuous physical activation method was able to expose mesopores and micropores that were previously covered/clogged in nature, and simultaneously create new pores. The synthesized bioadsorbents showed that the surface area (PKS: 456.47 m2 g-1, CS: 479.17 m2 g-1), pore size (PKS: 0.63 nm, CS: 0.62 nm) and pore volume (PKS: 0.13 cm3 g-1, CS: 0.15 cm3 g-1) were significantly higher than that of non-treated bioadsorbent. The surface morphology of the raw materials and synthesized bioadsorbent were accessed by SEM. Furthermore, the novel process meets the recent industrial adsorbent requirements such as low activation temperature, high fixed carbon content, high yield, high adsorption properties and high surface area, which are the key factors for large-scale production of bioadsorbent and its usage.
  19. Performances of Polymer-Dispersed Liquid Crystal Films for Smart Glass Applications
    Islam MS, Chan KY, Thien GSH, Low PL, Lee CL, Wong SK, et al.
    Polymers (Basel), 2023 Aug 16;15(16).
    PMID: 37631477 DOI: 10.3390/polym15163420
    Polymer-dispersed liquid crystal (PDLC) film is an active smart film penetrating the market due to its unique functionalities. These functional characteristics include switchable tint capabilities, which shield building residents from the sun's harmful ultraviolet (UV) rays, improve energy-saving features, and produce higher cost-efficiency. Although PDLC films are promising in several applications, there is still ambiguity on the performance of PDLC films. Particularly, the sizing effects' (such as film thickness and area) correlation with visible light transmission (VLT), ultraviolet rejection (UVR), infrared rejection (IRR), light intensity, current consumption, and apparent power consumption is not well understood. Therefore, this study investigated the sizing effects of PDLC films, including the thickness effect on VLT, UVR, IRR, light intensity, and area influence on current and apparent power consumptions. The varying applied voltage effect on the light transmittance of the PDLC film was also effectively demonstrated. A 0.1 mm PDLC film was successfully presented as a cost-efficient film with optimal parameters. Consequently, this study paves the way for a clearer understanding of PDLC films (behavior and sizing effects) in implementing economic PDLC films for large-scale adoption in commercial and residential premises.
  20. Fulltext Starch-Based Polymer Materials as Advanced Adsorbents for Sustainable Water Treatment: Current Status, Challenges, and Future Perspectives
    Khoo PS, Ilyas RA, Uda MNA, Hassan SA, Nordin AH, Norfarhana AS, et al.
    Polymers (Basel), 2023 Jul 21;15(14).
    PMID: 37514503 DOI: 10.3390/polym15143114
    Over the past three decades, chemical and biological water contamination has become a major concern, particularly in the industrialized world. Heavy metals, aromatic compounds, and dyes are among the harmful substances that contribute to water pollution, which jeopardies the human health. For this reason, it is of the utmost importance to locate methods for the cleanup of wastewater that are not genuinely effective. Owing to its non-toxicity, biodegradability, and biocompatibility, starch is a naturally occurring polysaccharide that scientists are looking into as a possible environmentally friendly material for sustainable water remediation. Starch could exhibit significant adsorption capabilities towards pollutants with the substitution of amide, amino, carboxyl, and other functional groups for hydroxyl groups. Starch derivatives may effectively remove contaminants such as oil, organic solvents, pesticides, heavy metals, dyes, and pharmaceutical pollutants by employing adsorption techniques at a rate greater than 90%. The maximal adsorption capacities of starch-based adsorbents for oil and organic solvents, pesticides, heavy metal ions, dyes, and pharmaceuticals are 13,000, 66, 2000, 25,000, and 782 mg/g, respectively. Although starch-based adsorbents have demonstrated a promising future for environmental wastewater treatment, additional research is required to optimize the technique before the starch-based adsorbent can be used in large-scale in situ wastewater treatment.
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