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Displaying publications 41 - 49 of 49 in total

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Electrovalent effects of sodium carboxymethyl cellulose and hydroxyethyl cellulose on regeneration of empty fruit bunch cellulose to A superabsorbent hydrogel

Salleh KM, Zakaria S, Armir NAZ, Khairunnisa-Atiqah MK, Wang B

Int J Biol Macromol, 2024 Aug 16.
PMID: 39154673 DOI: 10.1016/j.ijbiomac.2024.134816

The hydrogel regeneration process, involving various cellulose types, results in distinct chemical bonding patterns. Even minor variations in chemical interactions among polymers during regeneration significantly impact properties like hydrogel-forming ability, hydrophilicity, and swelling capacity. This study focuses on regenerating a superabsorbent hydrogel from the interplay of native empty fruit bunch cellulose (EFBC), sodium carboxymethyl cellulose (NaCMC), and hydroxyethyl cellulose (HEC) using epichlorohydrin (ECH) as a crosslinker. The hydrogel was formed from dissolved EFBC solutions in an aqueous NaOH/urea solvent, supplemented with different NaCMC and HEC weight ratios, and ECH chemically assisted the crosslinking process. EFBC provides the hydrogel's supporting skeletal structure, while NaCMC and HEC play vital roles in enhancing forming ability and its physical and mechanical properties through diverse chemical interactions based on their electrovalent properties. Notably, NaCMC imparts hydrophilicity, while HEC indirectly improves superabsorbent properties through the enhancement of the elastic network's retraction force. Hydrogels combining NaCMC and HEC show a remarkable water absorption capacity exceeding 30,000 %, surpassing those regenerated solely with EFBC and NaCMC. The highest swelling, over 130,000 %, is achieved with 0.75 % NaCMC and 0.25 % HEC. Regarding thermal stability, hydrogels with a higher NaCMC proportion outperform those with increased HEC content. The study highlights the critical role of tailored chemical interactions in successfully regenerating an improved superabsorbent hydrogel with enhanced water absorption properties.
Fulltext Antibacterial performance of Ag nanoparticles and AgGO nanocomposites prepared via rapid microwave-assisted synthesis method

Chook SW, Chia CH, Zakaria S, Ayob MK, Chee KL, Huang NM, et al.

Nanoscale Res Lett, 2012;7(1):541.
PMID: 23020815 DOI: 10.1186/1556-276X-7-541

Silver nanoparticles and silver-graphene oxide nanocomposites were fabricated using a rapid and green microwave irradiation synthesis method. Silver nanoparticles with narrow size distribution were formed under microwave irradiation for both samples. The silver nanoparticles were distributed randomly on the surface of graphene oxide. The Fourier transform infrared and thermogravimetry analysis results showed that the graphene oxide for the AgNP-graphene oxide (AgGO) sample was partially reduced during the in situ synthesis of silver nanoparticles. Both silver nanoparticles and AgGO nanocomposites exhibited stronger antibacterial properties against Gram-negative bacteria (Salmonella typhi and Escherichia coli) than against Gram-positive bacteria (Staphyloccocus aureus and Staphyloccocus epidermidis). The AgGO nanocomposites consisting of approximately 40 wt.% silver can achieve antibacterial performance comparable to that of neat silver nanoparticles.
Citric acid modified kenaf core fibres for removal of methylene blue from aqueous solution

Sajab MS, Chia CH, Zakaria S, Jani SM, Ayob MK, Chee KL, et al.

Bioresour Technol, 2011 Aug;102(15):7237-43.
PMID: 21620692 DOI: 10.1016/j.biortech.2011.05.011

Chemically modified kenaf core fibres were prepared via esterification in the presence of citric acid (CA). The adsorption kinetics and isotherm studies were carried out under different conditions to examine the adsorption efficiency of CA-treated kenaf core fibres towards methylene blue (MB). The adsorption capacity of the kenaf core fibres increased significantly after the citric acid treatment. The values of the correlation coefficients indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich isotherm. The maximum adsorption capacity of the CA-treated kenaf core fibres was found to be 131.6mg/g at 60°C. Kinetic models, pseudo-first-order, pseudo-second-order and intraparticle diffusion, were employed to describe the adsorption mechanism. The kinetic data were found to fit pseudo-second-order model equation as compared to pseudo-first-order model. The adsorption of MB onto the CA-treated kenaf core fibres was spontaneous and endothermic.
Fulltext Phylogenetic relationships of Malayan gaur with other species of the genus Bos based on cytochrome b gene DNA sequences

Rosli MK, Zakaria SS, Syed-Shabthar SM, Zainal ZZ, Shukor MN, Mahani MC, et al.

Genet. Mol. Res., 2011;10(1):482-93.
PMID: 21476194 DOI: 10.4238/vol10-1gmr1002

The Malayan gaur (Bos gaurus hubbacki) is one of the three subspecies of gaurs that can be found in Malaysia. We examined the phylogenetic relationships of this subspecies with other species of the genus Bos (B. javanicus, B. indicus, B. taurus, and B. grunniens). The sequence of a key gene, cytochrome b, was compared among 20 Bos species and the bongo antelope, used as an outgroup. Phylogenetic reconstruction was employed using neighbor joining and maximum parsimony in PAUP and Bayesian inference in MrBayes 3.1. All tree topologies indicated that the Malayan gaur is in its own monophyletic clade, distinct from other species of the genus Bos. We also found significant branching differences in the tree topologies between wild and domestic cattle.
Fulltext Production of Rigid Polyurethane Foams Using Polyol from Liquefied Oil Palm Biomass: Variation of Isocyanate Indexes

Amran UA, Salleh KM, Zakaria S, Roslan R, Chia CH, Jaafar SNS, et al.

Polymers (Basel), 2021 Sep 11;13(18).
PMID: 34577973 DOI: 10.3390/polym13183072

Development of polyurethane foam (PUF) containing bio-based components is a complex process that requires extensive studies. This work reports on the production of rigid PUFs from polyol obtained via liquefaction of oil palm empty fruit bunch (EFB) biomass with different isocyanate (NCO) indexes. The effect of the NCO index on the physical, chemical and compressive properties of the liquefied EFB-based PUF (EFBPUF) was evaluated. The EFBPUFs showed a unique set of properties at each NCO index. Foaming properties had affected the apparent density and cellular morphology of the EFBPUFs. Increasing NCO index had increased the crosslink density and dimensional stability of the EFBPUFs via formation of isocyanurates, which had also increased their thermal stability. Combination of both foaming properties and crosslink density of the EFBPUFs had influenced their respective compressive properties. The EFBPUF produced at the NCO index of 120 showed the optimum compressive strength and released the least toxic hydrogen cyanide (HCN) gas under thermal degradation. The normalized compressive strength of the EFBPUF at the NCO index of 120 is also comparable with the strength of the PUF produced using petrochemical polyol.
Fulltext Vitamin E improved bone strength and bone minerals in male rats given alcohol

Zakaria S, Mat-Husain SZ, Ying-Hwey K, Xin-Kai K, Mohd-Badawi A, Abd-Ghani NA, et al.

Iran J Basic Med Sci, 2017 Dec;20(12):1360-1367.
PMID: 29238472 DOI: 10.22038/IJBMS.2017.9610

Objectives: Alcohol consumption induces oxidative stress on bone, which in turn increases the risk of osteoporosis. This study determined the effects of vitamin E on bone strength and bone mineral content in alcohol-induced osteoporotic rats.
Materials and Methods: Three months old Sprague Dawley male rats were randomly divided into 5 groups: (I) control group; (II) alcohol (3g/kg) + normal saline; (III) alcohol (3g/kg) + olive oil; (IV) alcohol (3g/kg) + alpha-tocopherol (60mg/kg) and (V) alcohol (3g/kg) + palm vitamin E (60mg/kg). The treatment lasted for three months. Following sacrifice, the right tibia was subjected to bone biomechanical test while the lumbar (fourth and fifth lumbar) and left tibia bones were harvested for bone mineral measurement.
Results: Alcohol caused reduction in bone biomechanical parameters (maximum force, ultimate stress, yield stress and Young's modulus) and bone minerals (bone calcium and magnesium) compared to control group (P<0.05). Palm vitamin E was able to improve bone biomechanical parameters by increasing the maximum force, ultimate stress and Young's modulus (P<0.05) while alpha-tocopherol was not able to. Both alpha-tocopherol and palm vitamin E were able to significantly increase tibia calcium and magnesium content while only alpha-tocopherol caused significant increase in lumbar calcium content (P<0.05).
Conclusion: Both palm vitamin E and alpha-tocopherol improved bone mineral content which was reduced by alcohol. However, only palm vitamin E was able to improve bone strength in alcohol treated rats.
Fulltext Transition care readiness among patients in a tertiary paediatric department

Lau SC, Azim E, Abdul Latiff Z, Syed Zakaria SZ, Wong SW, Wu LL, et al.

Med J Malaysia, 2018 12;73(6):382-387.
PMID: 30647208

INTRODUCTION: A smooth transition of healthcare for young people with chronic illnesses from paediatric to adult healthcare services is important to ensure optimal outcome. At the moment, there are no standard guidelines to assess a patient's readiness to transfer care.

METHODS: A cross-sectional study using a self-administered questionnaire, adapted from UNC (University of North Carolina) TRxANSITION self-assessment tool was conducted to evaluate patients' transition care readiness in paediatric haematology and paediatric diabetes clinic.

RESULTS: A total of 80 patients (37 thalassaemia and 43 diabetes) with the mean age of 21.2 (SD±4.3) years, were recruited during the 3-month study period. Majority of the patients have basic knowledge regarding their medications, and were able to comply with their follow-up. The mean total score obtained by the respondents on this questionnaire was 15.3 (SD±3.59). Self-management skills and knowledge on disease were the two poorly scored section; with mean score of 3.78 (SD±1.38) and 4.28 (SD±1.20) respectively. Overall, only 21 (26.2%) respondents obtained high score (score above 75th percentile). Seventy-five percent of the respondents admitted that they were not ready for transfer to an adult healthcare service yet at the time of the study.

CONCLUSION: We suggest that patients with high score should be prepared for transition to adult facility whereas those with a low score need to be identified to ensure provision of continuous education.
Epidemiology and clinical profiles of cutaneous graft versus host disease in allogeneic peripheral blood stem cell transplantation

Kamal Rodin NS, Ismail NA, Abdul Wahid SF, Jamil A, Syed Zakaria SZ, Syed Abd Kadir SS, et al.

Malays J Pathol, 2021 Dec;43(3):361-373.
PMID: 34958057

INTRODUCTION: The epidemiology of cutaneous graft versus host disease (GVHD) in allogeneic peripheral blood stem cell transplantation (PBSCT) in Malaysia has not been described.
MATERIALS AND METHODS: We retrospectively analysed 691 allogeneic PBSCT patients between 2010-2017 in two centers.
RESULTS: The prevalence of cutaneous GVHD was 31.4% (217/691). No associations were detected with race, age or gender of donor and recipients. Cutaneous GVHD was associated with host cytomegalovirus (CMV) seropositivity (p<0.01), conditioning (p<0.01), GVHD prophylaxis (p=0.046) and survival (p<0.01). Majority developed the acute form (58.1%;126/217). Biopsies in 20.7% (45/217) showed 55.6% positivity for GVHD. Overall, involvement was non-severe. A majority demonstrated complete response (CR) to first-line corticosteroids (70.0%;152/217). Secondline therapies (extracorporeal phototherapy (ECP), psolaren ultraviolet A (PUVA), mycophenolate, tumour necrosis factor (TNF) inhibitors, interleukins inhibitors, or CD20 monoclonal antibodies) were required in 65/217, with 38.5% CR. Second-line therapy was associated with gender (p=0.042), extra-cutaneous GVHD (p=0.021), treatment outcomes (p=0.026) and survival (p=0.048). Mortality in cutaneous GVHD was 24.0% with severe sepsis being the leading cause at Day 100 (7.8%) and 5-years (7.8%), and relapsed disease at 2-years (32.7%). In steroid refractoriness, severe GVHD caused 30.8% mortality. In cutaneous GVHD, survival at Day 100 was 95.4%; 80.2% at 2-years and 73.1% at 5-years. The median survival in cutaneous GVHD was significantly shorter at 55 months, compared to those without GVHD at 69 months (p=0.001).
CONCLUSION: Cutaneous involvement is the commonest clinical manifestation of GVHD. A larger national study is warranted to further analyse severity and outcome of multiorgan GVHD, and factors associated with steroid refractoriness.
Fulltext Developing forecasting model for future pandemic applications based on COVID-19 data 2020-2022

Wan Mohamad Nawi WIA, K Abdul Hamid AA, Lola MS, Zakaria S, Aruchunan E, Gobithaasan RU, et al.

PLoS One, 2023;18(5):e0285407.
PMID: 37172040 DOI: 10.1371/journal.pone.0285407

Improving forecasting particularly time series forecasting accuracy, efficiency and precisely become crucial for the authorities to forecast, monitor, and prevent the COVID-19 cases so that its spread can be controlled more effectively. However, the results obtained from prediction models are inaccurate, imprecise as well as inefficient due to linear and non-linear patterns exist in the data set, respectively. Therefore, to produce more accurate and efficient COVID-19 prediction value that is closer to the true COVID-19 value, a hybrid approach has been implemented. Thus, aims of this study is (1) to propose a hybrid ARIMA-SVM model to produce better forecasting results. (2) to investigate in terms of the performance of the proposed models and percentage improvement against ARIMA and SVM models. statistical measurements such as MSE, RMSE, MAE, and MAPE then conducted to verify that the proposed models are better than ARIMA and SVM models. Empirical results with three real datasets of well-known cases of COVID-19 in Malaysia show that, compared to the ARIMA and SVM models, the proposed model generates the smallest MSE, RMSE, MAE and MAPE values for the training and testing datasets, means that the predicted value from the proposed model is closer to the actual value. These results prove that the proposed model can generate estimated values more accurately and efficiently. As compared to ARIMA and SVM, our proposed models perform much better in terms of error reduction percentages for all datasets. This is demonstrated by the maximum scores of 73.12%, 74.6%, 90.38%, and 68.99% in the MAE, MAPE, MSE, and RMSE, respectively. Therefore, the proposed model can be the best and effective way to improve prediction performance with a higher level of accuracy and efficiency in predicting cases of COVID-19.