Displaying publications 1 - 20 of 53 in total

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  1. Lee D, Kim K
    Acta Trop, 2024 Nov 26.
    PMID: 39608662 DOI: 10.1016/j.actatropica.2024.107481
    The coronavirus disease 2019 pandemic highlighted the necessity and limitations of scientific collaboration and equitable and effective international research partnerships. The spread of mosquito-borne diseases (MBDs) presents severe public health challenges, particularly in Southeast Asia. Addressing these threats requires establishing regional priorities, bridging research gaps, and strengthening long-term international collaboration. We propose a practical approach to multifaceted perspectives to enhance collaboration across Asia. This study examines MBD-related scientific publications from nine Southeast Asian countries between January 2017 and June 2024, utilizing bibliometric analysis and data visualization to identify research trends, research capacities, key institutions, and international collaborative partners. Thailand and Singapore led the dengue research, followed by Malaysia and Indonesia. Vietnam and the Philippines demonstrated moderate research capabilities, whereas Cambodia, Laos, and Myanmar had lower capacities. Relationships with high-income countries drove international collaboration, whereas intra-regional collaboration in Southeast Asia increased. Furthermore, we identified directions for cooperative opportunities between South Korea and other Southeast Asian countries by analyzing their relative research capacities for infectious MBDs. We propose a practical approach to bridge research-capacity gaps and strengthen collaboration between low- and middle-income countries. These findings provide fundamental information for developing future infectious-disease-response strategies and international-collaboration research partnerships and facilitate the implementation of effective global public health preparedness policies and evidence-based decision-making, such as knowledge-transfer and resource-sharing.
  2. Hapiz A, Jawad AH, Wilson LD, ALOthman ZA
    Int J Phytoremediation, 2024 Feb;26(3):324-338.
    PMID: 37545130 DOI: 10.1080/15226514.2023.2241912
    In this investigation, microwave irradiation assisted by ZnCl2 was used to transform pineapple crown (PN) waste into mesoporous activated carbon (PNAC). Complementary techniques were employed to examine the physicochemical characteristics of PNAC, including BET, FTIR, SEM-EDX, XRD, and pH at the point-of-zero-charge (pHpzc). PNAC is mesoporous adsorbent with a surface area of 1070 m2/g. The statistical optimization for the adsorption process of two model cationic dyes (methylene blue: MB and, crystal violet: CV) was conducted using the response surface methodology-Box-Behnken design (RSM-BBD). The parameters include solution pH (4-10), contact time (2-12) min, and PNAC dosage (0.02-0.1 g/100 mL). The Freundlich and Langmuir models adequately described the dye adsorption isotherm results for the MB and CV systems, whereas the pseudo-second order kinetic model accounted for the time dependent adsorption results. The maximum adsorption capacity (qmax) for PNAC with the two tested dyes are listed: 263.9 mg/g for CV and 274.8 mg/g for MB. The unique adsorption mechanism of MB and CV dyes by PNAC implicates multiple contributions to the adsorption process such as pore filling, electrostatic forces, H-bonding, and π-π interactions. This study illustrates the possibility of transforming PN into activated carbon (PNAC) with the potential to remove two cationic dyes from aqueous media.
  3. Hapiz A, Jawad AH, Alothman ZA, Wilson LD
    Int J Phytoremediation, 2024 May;26(7):1064-1075.
    PMID: 38084662 DOI: 10.1080/15226514.2023.2288904
    In this study, pineapple crown (PC) feedstock residues were utilized as a potential precursor toward producing activated carbon (PCAC) via pyrolysis induced with ZnCl2 activation. The PCAC has a surface area (457.8 m2/g) and a mesoporous structure with an average pore diameter of 3.35 nm, according to the Brunauer-Emmett-Teller estimate. The removal of cationic dye (Fuchsin basic; FB) was used for investigating the adsorption parameters of PCAC. The optimization of significant adsorption variables (A: PCAC dose (0.02-0.1 g/100 mL); B: pH (4-10); C: time (10-90); and D: initial FB concentration (10-50 mg/L) was conducted using the Box-Behnken design (BBD). The pseudo-second-order (PSO) model characterized the dye adsorption kinetic profile, whereas the Freundlich model reflected the equilibrium adsorption profile. The maximum adsorption capacity (qmax) of PCAC for FB dye was determined to be 171.5 mg/g. Numerous factors contribute to the FB dye adsorption mechanism onto the surface of PCAC, which include electrostatic attraction, H-bonding, pore diffusion, and π-π stacking. This study illustrates the utilization of PC biomass feedstock for the fabrication of PCAC and its successful application in wastewater remediation.
  4. Lee DW, Teoh DC, Chong FL
    Med J Malaysia, 2015 Apr;70(2):110-1.
    PMID: 26162391 MyJurnal
    We present a case of nasopharyngeal carcinoma complicated with hyperleucocytosis. After ruling our other causes we concluded that the hyperleucocytosis was due to paraneoplastic leukemoid reaction (PLR). The overall survival was 15 months which is rare among patients with PLR.
    Keywords: Sabah
  5. Lim TO, Lee DG, Zaki M
    Med J Malaysia, 2000 Jun;55(2):188-95.
    PMID: 19839147
    We determined the provision for dialysis treatment in Malaysia. There were 181 dialysis centres as at 1st June 1999 (161 Haemodialysis (HD) and 20 Continuous Ambulatory Peritoneal Dialysis (CAPD) centres), providing treatment for 5614 patients. This is equivalent to an estimated prevalence rate of 253 patients per million population (pmp) and new dialysis acceptance rate of 49 patients pmp. Dialysis facilities were widely distributed throughout the country though rather unevenly among states. Penang, Selangor/KL, Malacca led with number of dialysis patients pmp ranging from 417 to 480. Kelantan and Sabah had the lowest provision with 51 and 64 patients pmp respectively. There were more centres and HD capacity in the private sector while the Non-Government Organisation and public sectors had about the same capacity. However the public sector had more patients on account of availability of CAPD and home HD services, as well as low HD capacity to patient ratio. The number ofcentres, HD capacity and patients have increased rapidly especially since 1991; the estimated growth rates were 16.5 centres/year, 658 capacity/year, and 392 patients/year respectively. There was also a trend toward increasing over-capacity in the private and NGO sectors. In conclusion, the level of dialysis provision is increasing, indicating increasing accessibility of dialysis treatment in Malaysia. Over-capacity is a concern in the private and NGO sectors. Thus funding agencies should be encouraged to source provision from those sectors. The public sector still has the crucial role of providing for under-served areas in the country.
  6. Lee DW, Kang IH, Ismail F
    Med J Malaysia, 2020 07;75(4):338-341.
    PMID: 32723991
    OBJECTIVE: Three-weekly docetaxel causes a high rate of febrile neutropenia, especially in the Asian population. Two-weekly docetaxel has been shown to reduce rate of febrile neutropenia in castrate-resistant prostate cancer patients. We conducted a preliminary study to investigate the safety of two-weekly docetaxel in advanced breast cancer patients.

    METHODS: We recruited 10 patients with advanced breast cancer with ECOG (Eastern Cooperative Oncology Group) performance status score of zero to two, who needed chemotherapy in the first or second-line setting to receive two-weekly docetaxel for 8 cycles. The primary endpoint was safety and secondary endpoints were response rate and progression free survival.

    RESULTS: The most reported adverse events were haematological (anaemia 100% and neutropenia 90%). The febrile neutropenia rate was 10%. The overall response rate was 20%. The median progression free survival was 5.0 months.

    CONCLUSION: Two-weekly docetaxel may be a reasonable alternative treatment regimen for patients with advanced breast cancer in the first or second-line setting. This regimen is yet to be compared with standard 3-weekly schedule in a phase 3 randomised clinical trial.

  7. Lee DW, Tan GS, Liew FY
    Planta Med, 1977 Feb;31(1):83-93.
    PMID: 840935
  8. Lee D, Weinberg M, Benoit S
    Am J Public Health, 2017 05;107(5):684-686.
    PMID: 28323479 DOI: 10.2105/AJPH.2017.303698
    OBJECTIVES: To assess US availability and use of measles-mumps-rubella (MMR) vaccination documentation for refugees vaccinated overseas.

    METHODS: We selected 1500 refugee records from 14 states from March 2013 through July 2015 to determine whether overseas vaccination records were available at the US postarrival health assessment and integrated into the Advisory Committee on Immunization Practices schedule. We assessed number of doses, dosing interval, and contraindications.

    RESULTS: Twelve of 14 (85.7%) states provided data on 1118 (74.5%) refugees. Overseas records for 972 (86.9%) refugees were available, most from the Centers for Disease Control and Prevention's Electronic Disease Notification system (66.9%). Most refugees (829; 85.3%) were assessed appropriately for MMR vaccination; 37 (3.8%) should have received MMR vaccine but did not; 106 (10.9%) did not need the MMR vaccine but were vaccinated.

    CONCLUSIONS: Overseas documentation was available at most clinics, and MMR vaccinations typically were given when needed. Further collaboration between refugee health clinics and state immunization information systems would improve accessibility of vaccination documentation.

  9. Kusrini E, Usman A, Sani FA, Wilson LD, Abdullah MAA
    Environ Monit Assess, 2019 Jul 10;191(8):488.
    PMID: 31292792 DOI: 10.1007/s10661-019-7634-6
    This paper presents the adsorption capacity of a biosorbent derived from the inner part of durian (Durio zibethinus) rinds, which are a low-cost and abundant agro-waste material. The durian rind sorbent has been successfully utilized to remove lanthanum (La) and yttrium (Y) ions from their binary aqueous solution. The effects of several adsorption parameters including contact time, pH, concentrations of La and Y, and temperature on the removal of La and Y ions were investigated. The adsorption isotherm and kinetics of the metal ions were also evaluated in detail. Both La and Y ions were efficiently adsorbed by the biosorbent with optimum adsorption capacity as high as 71 mg La and 35 mg Y per gram biosorbent, respectively. The simultaneous adsorption of La and Y ions follows Langmuir isotherm model, due to the favorable chelation and strong chemical interactions between the functional groups on the surface of the biosorbent and the metal ions. The addition of oxygen content after adsorption offers an interpretation that the rare-earth metal ions are chelated and incorporated most probably in the form of metal oxides. With such high adsorption capacity of La and Y ions, the durian rind sorbent could potentially be used to treat contaminated wastewater containing La and Y metal ions, as well as for separating and extracting rare-earth metal ions from crude minerals.
  10. Iqbal A, Saidu U, Adam F, Sreekantan S, Yahaya N, Ahmad MN, et al.
    Molecules, 2021 Apr 25;26(9).
    PMID: 33923041 DOI: 10.3390/molecules26092509
    In this work, mesoporous TiO2-modified ZnO quantum dots (QDs) were immobilised on a linear low-density polyethylene (LLDPE) polymer using a solution casting method for the photodegradation of tetracycline (TC) antibiotics under fluorescent light irradiation. Various spectroscopic and microscopic techniques were used to investigate the physicochemical properties of the floating hybrid polymer film catalyst (8%-ZT@LLDPE). The highest removal (89.5%) of TC (40 mg/L) was achieved within 90 min at pH 9 due to enhanced water uptake by the LDDPE film and the surface roughness of the hybrid film. The formation of heterojunctions increased the separation of photogenerated electron-hole pairs. The QDs size-dependent quantum confinement effect leads to the displacement of the conduction band potential of ZnO QDs to more negative energy values than TiO2. The displacement generates more reactive species with higher oxidation ability. The highly stable film photocatalyst can be separated easily and can be repeatedly used up to 8 cycles without significant loss in the photocatalytic ability. The scavenging test indicates that the main species responsible for the photodegradation was O2●-. The proposed photodegradation mechanism of TC was demonstrated in further detail based on the intermediates detected by LC-time-of-flight/mass spectrometry (LC/TOF-MS).
  11. Manaf NA, Saad B, Mohamed MH, Wilson LD, Latiff AA
    J Chromatogr A, 2018 Mar 30;1543:23-33.
    PMID: 29478831 DOI: 10.1016/j.chroma.2018.02.032
    Sorbents were prepared by cross-linking β-cyclodextrin (β-CD) using two different types of cross-linker units at variable reactant mole ratios. The resulting polymers containing β-CD were evaluated as sorbents in micro-solid phase extraction (μ-SPE) format for the extraction of the endogenous steroids testosterone (T), epitestosterone (E), androsterone (A), etiocholanolone (Etio), 5α-androstane-3α,17β-diol (5αAdiol) and 5β-androstane-3α,17β-diol (5βAdiol). The best sorbent (C1; cyclodextrin polymer) showed superior extraction characteristics compared with commercial sorbents (C18 and Bond Elut Plexa). Parameters influencing the extraction efficiency of the C1 sorbent such as extraction and desorption times, desorption solvent and volume of sample were investigated. The extracts were separated using a Hypersil Gold column (50 × 2.1 mm, 1.9 μm) under gradient elution coupled to a LC-MS/MS. The compounds were successfully separated within 8 min. The method offers good repeatability (RSD  0.995) were within the range of 1-200 ng mL-1 for T and E, 250-4000 ng mL-1 for A and Etio and 25-500 ng mL-1 for 5αAdiol and 5βAdiol, respectively. The method was applied for the determination of steroid profile of urine from volunteers.
  12. Reghioua A, Jawad AH, Selvasembian R, ALOthman ZA, Wilson LD
    Int J Phytoremediation, 2023;25(14):1988-2000.
    PMID: 37291893 DOI: 10.1080/15226514.2023.2216304
    This research aims to convert pomegranate peel (PP) into microporous activated carbon (PPAC) using a microwave assisted K2CO3 activation method. The optimum activation conditions were carried out with a 1:2 PP/K2CO3 impregnation ratio, radiation power 800 W, and 15 min irradiation time. The statistical Box-Behnken design (BBD) was employed as an effective tool for optimizing the factors that influence the adsorption performance and removal of methylene blue (MB) dye. The output data of BBD with a desirability function indicate a 94.8% removal of 100 mg/L MB at the following experimental conditions: PPAC dose of 0.08 g, solution pH of 7.45, process temperature of 32.1 °C, and a time of 30 min. The pseudo-second order (PSO) kinetic model accounted for the contact time for the adsorption of MB. At equilibrium conditions, the Freundlich adsorption isotherm describes the adsorption results, where the maximum adsorption capacity of PPAC for MB dye was 291.5 mg g-1. This study supports the utilization of biomass waste from pomegranate peels and conversion into renewable and sustainable adsorbent materials. As well, this work contributes to the management of waste biomass and water pollutant sequestration.
  13. Arni LA, Hapiz A, Abdulhameed AS, Khadiran T, ALOthman ZA, Wilson LD, et al.
    Int J Biol Macromol, 2023 Jul 01;242(Pt 4):125086.
    PMID: 37247708 DOI: 10.1016/j.ijbiomac.2023.125086
    In this study, a magnetic chitosan grafted-benzaldehyde (CS-BD/Fe3O4) was hydrothermally prepared using benzaldehyde as a grafting agent to produce a promising adsorbent for the removal of acid red 88 (AR88) dye. The CS-BD/Fe3O4 was characterized by infrared spectroscopy, surface area analysis, scanning electron microscopy-energy dispersive X-ray, vibrating sample magnetometry, powder X-ray diffraction, CHN elemental analysis, and point of zero charge (pHPZC). The Box-Behnken design (BBD) was adopted to study the role of variables that influence AR88 dye adsorption (A: CS-BD/Fe3O4 dose (0.02-0.1 g), B: pH (4-10), and time C: (10-90 min)). The ANOVA results of the BBD model indicated that the F-value for the AR88 removal was 22.19 %, with the corresponding p-value of 0.0002. The adsorption profiles at equilibrium and dynamic conditions reveal that the Temkin model and the pseudo-first-order kinetics model provide an adequate description of the isotherm results, where the maximum adsorption capacity (qmax) with the AR88 dye was 154.1 mg/g. Several mechanisms, including electrostatic attraction, n-π interaction, π-π interaction, and hydrogen bonding, regulate the adsorption of AR88 dyes onto the CS-BD/Fe3O4 surface. As a result, this research indicates that CS-BD/Fe3O4 can be utilized as an effective and promising bio-adsorbent for azo dye removal from contaminated wastewater.
  14. Wu R, Abdulhameed AS, Yong SK, Li H, ALOthman ZA, Wilson LD, et al.
    Int J Biol Macromol, 2023 Aug 30;247:125806.
    PMID: 37453635 DOI: 10.1016/j.ijbiomac.2023.125806
    An effective hydrothermally prepared chitosan-benzaldehyde/SiO2 adsorbent (CTA-BZA/SiO2) employed functionalization of a CTA biopolymer with SiO2 nanoparticles and BZA. CTA-BZA/SiO2 is an adsorbent that was utilized for the adsorption of an acidic dye (acid red 88, AR88) from synthetic wastewater. The fundamental adsorption variables (A: CTA-BZA/SiO2 dosage (0.02-0.1 g); B: pH (4-10); and C: duration (10-60)) were optimized via the Box-Behnken design (BBD). The Langmuir and Freundlich isotherms (coefficients of determination R2 = 0.99) agreed well with empirical data of AR88 adsorption by CTA-BZA/SiO2. The pseudo-first-order model showed reasonable agreement with the kinetic data of AR88 adsorption by CTA-BZA/SiO2. The maximal AR88 adsorption capacity (qmax) for CTA-BZA/SiO2 was identified to be 252.4 mg/g. The electrostatic attractions between both the positively charged CTA-BZA/SiO2 adsorbent and the AR88 anions, plus the n-π, π-π, and H-bond interactions contribute to the favourable adsorption process. This study reveals that CTA-BZA/SiO2 has the capacity to be a suitable adsorbent for the removal of a wider range of organic dyes from industrial effluents.
  15. Arni LA, Hapiz A, Jawad AH, Abdulhameed AS, ALOthman ZA, Wilson LD
    Int J Biol Macromol, 2023 Sep 01;248:125943.
    PMID: 37482164 DOI: 10.1016/j.ijbiomac.2023.125943
    Herein, a novel nanohybrid composite of magnetic chitosan-salicylaldehyde/nanoclay (MCH-SAL/NCLA) was hydrothermally synthesized for removal of azo dye (acid red 88, AR88) from simulated wastewater. Response surface methodology combined with the Box-Behnken design (RSM-BBD) was applied with 29 experiments to assess the impact of adsorption variables, that include A: % NCLA loading (0-50), B: MCH-SAL/NCLA dose (0.02-0.1 g/100 mL), C: pH (4-10), and time D: (10-90 min) on AR88 dye adsorption. The highest AR88 removal (75.16 %) as per desirability function was attained at the optimum conditions (NCLA loading = 41.8 %, dosage = 0.06 g/100 mL, solution pH = 4, and time = 86. 17 min). The kinetic and equilibrium adsorption results of AR88 by MCH-SAL/NCLA reveal that the process follows the pseudo-first-order and Temkin models. The MCH-SAL/NCLA composite has a maximum adsorption capacity (173.5 mg/g) with the AR88 dye. The adsorption of AR88 onto the MCH-SAL/NCLA surface is determined by a variety of processes, including electrostatic, hydrogen bonding, n-π, and n-π interactions. This research revealed that MCH-SAL/NCLA can be used as a versatile and efficient bio-adsorbent for azo dye removal from contaminated wastewater.
  16. Abdulhameed AS, Hapiz A, Musa SA, ALOthman ZA, Wilson LD, Jawad AH
    Int J Biol Macromol, 2024 Jan;255:128075.
    PMID: 37977465 DOI: 10.1016/j.ijbiomac.2023.128075
    Herein, a quadruple biomagnetic nanocomposite of cross-linked chitosan-ethylene glycol diglycidyl ether/organo-nanoclay (MCH-EGDE/ORNC) was designed for the uptake of remazol brilliant blue R (RBBR) dye from aqueous environment. The adsorption process was systematically improved via the Box-Behnken design (BBD) to determine the influence of key uptake parameters, including MCH-EGDE/ORNC dosage, pH, and time, on the RBBR removal. The highest RBBR removal of 87.5 % was achieved at the following conditions: MCH-EGDE/ORNC dosage: 0.1 g/100 mL; pH: 4.0; contact time: 25 min. The findings of the kinetics and equilibrium studies revealed an excellent fit to the pseudo-second order and the Freundlich models, respectively. The adsorption capacity of the MCH-EGDE/ORNC for RBBR was found to be 168.4 mg/g, showcasing its remarkable adsorption capability. The present work highlights the potential of MCH-EGDE/ORNC biomaterial as an advanced adsorbent and lays the foundation for future applications in water purification and environmental remediation.
  17. Hapiz A, Jawad AH, Wilson LD, ALOthman ZA, Abdulhameed AS, Algburi S
    Int J Phytoremediation, 2024;26(4):579-593.
    PMID: 37740456 DOI: 10.1080/15226514.2023.2256412
    In this study, bamboo waste (BW) was subjected to pyrolysis-assisted ZnCl2 activation to produce mesoporous activated carbon (BW-AC), which was then evaluated for its ability to remove cationic dyes, specifically methylene blue (MB) and crystal violet (CV), from aqueous environments. The properties of BW-AC were characterized using various techniques, including potentiometric-based point of zero charge (pHpzc), scanning electron microscopy with energy dispersive X-rays (SEM-EDX), X-ray diffraction (XRD), gas adsorption with Brunauer-Emmett-Teller (BET) analysis, infrared (IR) spectroscopy. To optimize the adsorption characteristics (BW-AC dosage, pH, and contact time) of PBW, a Box-Behnken design (BBD) was employed. The BW-AC dose of 0.05 g, solution pH of 10, and time of 8 min are identified as optimal operational conditions for achieving maximum CV (89.8%) and MB (96.3%) adsorption according to the BBD model. The dye removal kinetics for CV and MB are described by the pseudo-second-order model. The dye adsorption isotherms revealed that adsorption of CV and MB onto BW-AC follow the Freundlich model. The maximum dye adsorption capacities (qmax) of BW-AC for CV (530 mg/g) and MB (520 mg/g) are favorable, along with the thermodynamics of the adsorption process, which is characterized as endothermic and spontaneous. The adsorption mechanism of CV and MB dyes by BW-AC was attributed to multiple contributions: hydrogen bonding, electrostatic forces, π-π attraction, and pore filling. The findings of this study highlight the potential of BW-AC as an effective adsorbent in wastewater treatment applications, contributing to the overall goal of mitigating the environmental impact of cationic dyes and ensuring the quality of water resources.
  18. Agha HM, Abdulhameed AS, Jawad AH, Sidik NJ, Aazmi S, Wilson LD, et al.
    Int J Phytoremediation, 2024;26(4):459-471.
    PMID: 37583281 DOI: 10.1080/15226514.2023.2246596
    This work aims to apply the use of food-grade algae (FGA) composited with chitosan-benzaldehyde Schiff base biopolymer (CHA-BD) as a new adsorbent (CHA-BA/FGA) for methyl violet 2B (MV 2B) dye removal from aqueous solutions. The effect of three processing variables, including CHA-BA/FGA dosage (0.02-0.1 g/100 mL), pH solution (4-10), and contact duration (10-120 min) on the removal of MV 2B was investigated using the Box-Behnken design (BBD) model. Kinetic and equilibrium dye adsorption profiles reveal that the uptake of MV 2B dye by CHA-BA/FGA is described by the pseudo-second kinetics and the Langmuir models. The thermodynamics of the adsorption process (ΔG°, ΔH°, and ΔS°) reveal spontaneous and favorable adsorption parameters of MV 2B dye onto the CHA-BA/FGA biocomposite at ambient conditions. The CHA-BA/FGA exhibited the maximum ability to absorb MV 2B of 126.51 mg/g (operating conditions: CHA-BA/FGA dose = 0.09 g/100 mL, solution pH = 8.68, and temperature = 25 °C). Various interactions, including H-bonding, electrostatic forces, π-π stacking, and n-π stacking provide an account of the hypothesized mechanism of MV 2B adsorption onto the surface of CHA-BA/FGA. This research reveals that CHA-BA/FGA with its unique biocomposite structure and favorable adsorption properties can be used to remove harmful cationic dyes from wastewater.
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