Displaying publications 1 - 20 of 26 in total

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  1. Omar R, Knight VF, Hussin DA
    Med J Malaysia, 2013 Jun;68(3):245-8.
    PMID: 23749015 MyJurnal
    This study determined the outcome of combining home based and clinic based amblyopia therapy among preschool children. A total of 479 preschool children were randomly selected for vision screening. Amblyopic therapy was prescribed to children whose visual acuity (VA) could not be improved to <0.1 LogMAR after a 6 week adaptation period with glasses. Intensive near work activities were conducted daily at home for 12 weeks, monitored by parents while weekly therapy was conducted at the optometry clinic by an optometrist. Six preschool children were diagnosed with refractive amblyopia, spherical equivalent (SE) was -11.25D to +0.75D. Significant improvement was found in the VA of right eye, t(6) = 3.07, left eye t(6) = 3.07 and both eyes t(6) = 3.42) p<0.05, at the end of the 12 week therapy. Combining home based and clinic based amblyopia therapy among preschool children showed a positive improvement in VA after 12 weeks of therapy.
    Study site: kindergarten, optometry clinic, Perak (site unclear)
  2. Omar R, Mohammed Z, Knight VF, Basrul MH
    Med J Malaysia, 2009 Dec;64(4):289-93.
    PMID: 20954552
    This study looked at the causes of vision loss, levels of distance, near vision and the use of low vision devices (LVDs) in children studying at special schools in Malaysia. A total of 139 children from two special education schools took part. Visual acuity was measured with and without LVDs. Those who required further assessment were referred to Low Vision Clinic. Near visual acuity in 71 children ranged from N4 to N64. Sixty eight children could not read the N64 chart or they were totally blind. Only eight students were using LVDs before intervention. Seventy one children were referred for low vision assessment and 48 were found to benefit from the LVDs prescribed. The major cause of visual impairment was cataract (17%). Hand held magnifier was the most preferred LVD. Majority of the children attending the blind schools had residual vision but did not have LVDs. LVDs are able to significantly improve near visual acuity and hence there is a need to prescribe and train the children to use the LVDs.
  3. Tan XL, Omar R, Knight VF
    Malays J Med Sci, 2023 Dec;30(6):147-155.
    PMID: 38239245 DOI: 10.21315/mjms2023.30.6.14
    BACKGROUND: Certified training must be provided for lay vision screeners prior to their conduct of a vision screening programme. However, the effectiveness of trained lay screeners does deteriorate over time. This study aims to evaluate the effectiveness of a recertification vision screening training module using the KieVision™ Preschool Vision Screening Kit for preschool teachers in Malaysia.

    METHODS: This was a randomised control trial. Fifty-nine preschool teachers previously enrolled in a Knowledge Transfer Programme were divided into a Study Group (n = 31) to receive recertification training and a Control Group (n = 28) to attend briefing sessions. Subjects was then asked to perform vision screening on 15 preschool children aged 4 years old-6 years old at their respective premises, then verified by optometrists after 2 weeks from the initial screening on the same children.

    RESULTS: A total of 894 children were screened, with the Study Group and Control Group screened 49.7% and 50.3%, respectively. There was higher validity in vision screening findings from the Study Group (sensitivity = 66.7%, positive predictive value (PPV) = 61.5%) compared to the Control Group (sensitivity = 36.0 %, PPV = 40.9%).

    CONCLUSION: Teachers who received recertification training were more competent in detecting children's vision impairment using KieVision™ Preschool Vision Screening Kit. Thus, timely recertification training should be emphasised to ensure sustainable consistency and reliability of vision screening programmes conducted by lay vision screeners.

  4. Johari HM, Zainudin HA, Knight VF, Lumley SA, Subramanium AS, Caszo BA, et al.
    J Sports Med Phys Fitness, 2017 Apr;57(4):396-401.
    PMID: 27045742 DOI: 10.23736/S0022-4707.16.06292-7
    BACKGROUND: Anthropometric and lung function characteristics of triathletes are important for the implementation of individual specific training and recovery recommendations. However, limited data are available for these parameters in triathletes. Hence, the aim of this study was to characterize and examine the gender differences of lung function and anthropometry parameters in competitive triathletes from Malaysia.

    METHODS: Body composition assessment and lung function tests were performed on sixteen competitive triathletes (nine male and seven female). The subject's body composition profile including muscle mass (kg), fat free mass (kg), and percent body fat was measured using a bio-impedance segmental body composition analyzer. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were measured by Quark PFT2 spirometer.

    RESULTS: The anthropometric measurements revealed that male triathletes were significantly taller than female triathletes and had significantly more protein and skeletal muscle mass. The female triathletes, however, had significantly higher percent body fat. Male triathletes had statistically significant higher FVC and FEV1 than female triathletes. Both the male and female triathletes showed a positive correlation between height, fat free mass and the lung function markers FVC and FEV1. This association was not seen with Body Mass Index (BMI) in female triathletes.

    CONCLUSIONS: The data from our study shows that anthropometric parameters are directly linked to lung function of a triathlete. We also found the relationship between BMI and lung function to be gender specific in triathletes and is dependent on the body protein and fat content. Hence, body composition characterization is essential and provides valuable information for developing individual specific training modules.
  5. Zainudin H, Caszo BA, Knight VF, Gnanou JV
    Eurasian J Med, 2019 Jun;51(2):116-120.
    PMID: 31258349 DOI: 10.5152/eurasianjmed.2019.18106
    Objective: Regular moderate-intensity exercise has beneficial health effects, whereas regular strenuous exercise increases the production of oxidants that may lead to DNA, skeletal, and cardiac muscle damages. Triathletes experience strenuous muscular activity both during competition and training, being at risk of developing these tissue damages. The objective of the present study was to estimate DNA, skeletal, and cardiac muscle damages using blood biomarkers, 8-hydroxy-2'-deoxyguanosine (8-OHdG), myoglobin, and cardiac troponin I (cTnI) among young triathletes.

    Materials and Methods: Age-matched seven male and seven female triathletes were recruited for the study. They were on a standardized training regimen and on average competed in at least one endurance event every month for the past 3-4 years. Serum biomarkers were measured using enzyme-linked immunosorbent assay at the start and at end of the racing season.

    Results: Both male and female triathletes showed a statistically significant increase in 8-OHdG. A similar pattern of increase was seen with serum myoglobin, which was not statistically significant in both male and female triathletes. cTnI levels did not show any change in both sexes.

    Conclusion: Our study shows that there could be an increased evidence of DNA damage among triathletes. However, similar effects were not observed with skeletal and cardiac muscle biomarkers.

  6. Osman MJ, Abdul Rashid JI, Khim OK, Zin Wan Yunus WM, Mohd Noor SA, Mohd Kasim NA, et al.
    RSC Adv, 2021 Jul 27;11(42):25933-25942.
    PMID: 35479481 DOI: 10.1039/d1ra04318h
    Acephate (Ac) is an organophosphate (OP) compound, which is able to inhibit the activity of acetylcholinesterase. Thus, the aim of this study was to optimize the detection of Ac using a thiolated acephate binding aptamer-citrate capped gold nanoparticle (TABA-Cit-AuNP) sensor that also incorporated an image processing technique. The effects of independent variables, such as the incubation period of TABA-Cit-AuNPs (3-24 h) for binding TABA to Cit-AuNPs, the concentration of phosphate buffer saline (PBS) (0.001-0.01 M), the concentration of thiolated acephate binding aptamer (TABA) (50-200 nM), and the concentration of magnesium sulphate (MgSO4) (1-300 mM) were investigated. A quadratic model was developed using a central composite design (CCD) from response surface methodology (RSM) to predict the sensing response to Ac. The optimum conditions such as the concentration of PBS (0.01 M), the concentration of TABA (200 nM), the incubation period of TABA-Cit-AuNPs (3 h), and the concentration of MgSO4 (1 mM) were used to produce a TABA-Cit-AuNPs sensor for the detection of Ac. Under optimal conditions, this sensor showed a detection ranging from 0.01 to 2.73 μM and a limit of detection (LOD) of 0.06 μM. Real sample analysis demonstrated this aptasensor as a good analytical method to detect Ac.
  7. Faiz Norrrahim MN, Mohd Kasim NA, Knight VF, Mohamad Misenan MS, Janudin N, Ahmad Shah NA, et al.
    RSC Adv, 2021 Feb 10;11(13):7347-7368.
    PMID: 35423275 DOI: 10.1039/d0ra08005e
    Chemical contaminants such as heavy metals, dyes, and organic oils seriously affect the environment and threaten human health. About 2 million tons of waste is released every day into the water system. Heavy metals are the largest contributor which cover about 31% of the total composition of water contaminants. Every day, approximately 14 000 people die due to environmental exposure to selected chemicals. Removal of these contaminants down to safe levels is expensive, high energy and unsustainable by current approaches such as oxidation, biodegradation, photocatalysis, precipitation, reverse osmosis and adsorption. A combination of biosorption and nanotechnology offers a new way to remediate these chemical contaminants. Nanostructured materials are proven to have higher adsorption capacities than the same material in its larger-scale form. Nanocellulose is very promising as a high-performance bioadsorbent due to its interesting characteristics of high adsorption capacity, high mechanical strength, hydrophilic surface chemistry, renewability and biodegradability. It has been proven to have higher adsorption capacity and better binding affinity than other similar materials at the macroscale. The high specific surface area and abundance of hydroxyl groups within lead to the possible functionalization of this material for decontamination purposes. Several research papers have shown the effectiveness of nanocellulose in the remediation of chemical contaminants. This review aims to provide an overview of the most recent developments regarding nanocellulose as an adsorbent for chemical contamination remediation. Recent advancements regarding the modification of nanocellulose to enhance its adsorption efficiency towards heavy metals, dyes and organic oils were highlighted. Moreover, the desorption capability and environmental issue related to every developed nanocellulose-based adsorbent were also tackled.
  8. Norizan MN, Moklis MH, Ngah Demon SZ, Halim NA, Samsuri A, Mohamad IS, et al.
    RSC Adv, 2024 Mar 20;14(14):9570.
    PMID: 38516155 DOI: 10.1039/d4ra90025a
    [This corrects the article DOI: 10.1039/D0RA09438B.].
  9. Norizan MN, Moklis MH, Ngah Demon SZ, Halim NA, Samsuri A, Mohamad IS, et al.
    RSC Adv, 2020 Nov 27;10(71):43704-43732.
    PMID: 35519676 DOI: 10.1039/d0ra09438b
    Carbon nanotubes (CNTs) have been recognised as a promising material in a wide range of applications, from safety to energy-related devices. However, poor solubility in aqueous and organic solvents has hindered the utilisation and applications of carbon nanotubes. As studies progressed, the methodology for CNTs dispersion was established. The current state of research in CNTs either single wall or multiwall/polymer nanocomposites has been reviewed in context with the various types of functionalisation presently employed. Functionalised CNTs have been playing an increasingly central role in the research, development, and application of carbon nanotube-based nanomaterials and systems. The extremely high surface-to-volume ratio, geometry, and hollow structure of nanomaterials are ideal for the adsorption of gas molecules. This offers great potential applications, such as in gas sensor devices working at room temperature. Particularly, the advent of CNTs has fuelled the invention of CNT-based gas sensors which are very sensitive to the surrounding environment. The presence of O2, NH3, NO2 gases and many other chemicals and molecules can either donate or accept electrons, resulting in an alteration of the overall conductivity. Such properties make CNTs ideal for nano-scale gas-sensing materials. Conductive-based devices have already been demonstrated as gas sensors. However, CNTs still have certain limitations for gas sensor application, such as a long recovery time, limited gas detection, and weakness to humidity and other gases. Therefore, the nanocomposites of interest consisting of polymer and CNTs have received a great deal of attention for gas-sensing application due to higher sensitivity over a wide range of gas concentrations at room temperature compared to only using CNTs and the polymer of interest separately.
  10. Dzulkurnain NA, Mokhtar M, Rashid JIA, Knight VF, Wan Yunus WMZ, Ong KK, et al.
    Polymers (Basel), 2021 Aug 15;13(16).
    PMID: 34451266 DOI: 10.3390/polym13162728
    Conducting polymers have been widely used in electrochemical sensors as receptors of the sensing signal's analytes and transducers. Polypyrrole (PPy) conducting polymers are highlighted due to their good electrical conductive properties, ease in preparation, and flexibility of surface characteristics. The objective of this review paper is to discuss the theoretical background of the two main types of electrochemical detection: impedimetric and voltammetric analysis. It also reviews the application and results obtained from these two electrochemical detections when utilizing PPy as a based sensing material in electrochemical sensor. Finally, related aspects in electrochemical sensor construction using PPy will also be discussed. It is anticipated that this review will provide researchers, especially those without an electrochemical analysis background, with an easy-to-understand summary of the concepts and technologies used in electrochemical sensor research, particularly those interested in utilizing PPy as a based sensing material.
  11. 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.
  12. Norrrahim MNF, Mohd Kasim NA, Knight VF, Ong KK, Mohd Noor SA, Abdul Halim N, et al.
    Polymers (Basel), 2021 Sep 24;13(19).
    PMID: 34641067 DOI: 10.3390/polym13193249
    The wide availability and diversity of dangerous microbes poses a considerable problem for health professionals and in the development of new healthcare products. Numerous studies have been conducted to develop membrane filters that have antibacterial properties to solve this problem. Without proper protective filter equipment, healthcare providers, essential workers, and the general public are exposed to the risk of infection. A combination of nanotechnology and biosorption is expected to offer a new and greener approach to improve the usefulness of polysaccharides as an advanced membrane filtration material. Nanocellulose is among the emerging materials of this century and several studies have proven its use in filtering microbes. Its high specific surface area enables the adsorption of various microbial species, and its innate porosity can separate various molecules and retain microbial objects. Besides this, the presence of an abundant OH groups in nanocellulose grants its unique surface modification, which can increase its filtration efficiency through the formation of affinity interactions toward microbes. In this review, an update of the most relevant uses of nanocellulose as a new class of membrane filters against microbes is outlined. Key advancements in surface modifications of nanocellulose to enhance its rejection mechanism are also critically discussed. To the best of our knowledge, this is the first review focusing on the development of nanocellulose as a membrane filter against microbes.
  13. Mezbah U, Omar R, Md Isa Z, Knight VF
    PMID: 37641697 DOI: 10.51329/mehdiophthal1439
    BACKGROUND: Clear vision is crucial for effective learning among preschool children. Hence, early detection of vision impairment and prompt treatment are required to improve prognosis. Currently, limited information is available, and no program exists to screen for vision impairment among preschoolers in Bangladesh. This study aimed to validate the KieVision™ Preschool Vision Screening Kit, translated into the Bengali language, to improve vision impairment detection among preschool children.

    METHODS: In this prospective case-control study, 60 preschool teachers from Chittagong were randomly selected. The study group was trained to conduct vision screening among preschool children using the translated kit, whereas the control group was trained using the Chittagong Eye Infirmary and Training Complex (CEITC) School Teachers' Training Module. Fifteen preschool children aged 4-6 years were screened by each preschool teacher and again by the optometrist.

    RESULTS: Sixty preschool teachers screened 900 children. The results showed a higher validity of vision screening findings by the preschool teachers in the study group (sensitivity, 68.00%; specificity, 92.75%) than in the control group (sensitivity 47.37%, specificity 70.39%). The level of agreement between the preschool teachers and optometrists was high for all tests (first-order agreement coefficient [AC1] ≥ 0.80 in the study group). The sensitivity and specificity of the visual acuity test for the study group were 59.65% and 94.15%, respectively, while in the control group it was 13.33% and 62.54%, respectively. A similar trend was noted in the general observation component and Hirschberg's test.

    CONCLUSIONS: The Bengali Language KieVision™ Preschool Vision Screening Kit can be used effectively by preschool teachers in vision screening programs to improve the identification of vision impairment among preschool children in Bangladesh.

  14. Nasir MHM, Taha MM, Razali N, Ilyas RA, Knight VF, Norrrahim MNF
    Materials (Basel), 2022 Nov 15;15(22).
    PMID: 36431566 DOI: 10.3390/ma15228082
    The thermal and rheological properties of bio-composite filament materials are crucial characteristics in the development of a bio-composite Fused Deposition Modeling (FDM) filament since the printing mechanism of FDM strongly depends on the heating and extrusion process. The effect of chemical treatment on the thermal and rheological properties was investigated to develop composite filaments for FDM using natural fibres such as sugar palm fibre (SPF). SPF underwent alkaline and silane treatment processes before being reinforced with PLA for improving adhesion and removing impurities. Thermogravimetric Analysis (TGA), Differential Scanning Calorimetric (DSC), and Melt Flow Index (MFI) analyses were conducted to identify the differences in thermal properties. Meanwhile, a rheological test was conducted to investigate the shear stress and its viscosity. The TGA test shows that the SPF/PLA composite treated with NaOH and silane showed good thermal stability at 789.5 °C with 0.4% final residue. The DSC results indicate that the melting temperature of all samples is slightly the same at 155 °C (in the range of 1 °C), showing that the treatment does not interfere with the melting temperature of the SPF/PLA composite. Thus, the untreated SPF/PLA composite showed the highest degradation temperature, which was 383.2 °C. The SPF/PLA composite treated with NaOH and silane demonstrated the highest melt flow index of 17.6 g/min. In conclusion, these findings offer a reference point for determining the filament extrusion and printability of SPF/PLA composite filaments.
  15. Taharuddin NH, Jumaidin R, Ilyas RA, Kamaruddin ZH, Mansor MR, Md Yusof FA, et al.
    Materials (Basel), 2022 Dec 15;15(24).
    PMID: 36556760 DOI: 10.3390/ma15248954
    Thermoplastic starch is a material that has the potential to be environmentally friendly and biodegradable. However, it has certain drawbacks concerning its mechanical performance and is sensitive to the presence of moisture. The current study assessed agar-containing thermoplastic sago starch (TPSS) properties at various loadings. Variable proportions of agar (5%, 10%, and 15% wt%) were used to produce TPSS by the hot-pressing method. Then, the samples were subjected to characterisation using scanning electron microscopy (SEM), mechanical analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and moisture absorption tests. The results demonstrated that adding agar to starch-based thermoplastic blends significantly improved their tensile, flexural, and impact properties. The samples' morphology showed that the fracture had become more erratic and uneven after adding agar. FT-IR revealed that intermolecular hydrogen bonds formed between TPSS and agar. Moreover, with an increase in agar content, TPSS's thermal stability was also increased. However, the moisture absorption values among the samples increased slightly as the amount of agar increased. Overall, the proposed TPSS/agar blend has the potential to be employed as biodegradable material due to its improved mechanical characteristics.
  16. Nafis ZAS, Nuzaimah M, Kudus SIA, Yusuf Y, Ilyas RA, Knight VF, et al.
    Materials (Basel), 2023 Jan 04;16(2).
    PMID: 36676215 DOI: 10.3390/ma16020479
    The efficacy of wood dust fibre treatment on the property of wood dust reinforced recycled polypropylene composite (r-WoPPC) filament was investigated. The wood dust fibre was treated using alkali, silane, and NaOH-silane. The treated wood fibre was incorporated with r-PP using a twin-screw extruder to produce filament. The silane treatment on wood dust fibre enhances interfacial bonding between wood fibre and recycled PP; hence, a filament has the highest wire pull strength, which is 35.2% higher compared to untreated and alkaline-treated wood dust filament. It is because silanol in silane forms a siloxane bond that acts as a coupling agent that improves interfacial bonding between wood dust fibre and recycled PP. The SEM micrograph of the fracture structure reveals that treated silane has strong interfacial bonding between wood dust fibre and recycled PP, having minimal void, gap, and good fibre adhesion. The water absorption test results indicate that filament with treated wood dust absorbs less water than filament with untreated wood because the treatment minimizes the gap between wood fibres and recycled PP. The FTIR analysis identified the presence of silane on the wood dust surface for silane-treated wood dust. The DSC studies suggest that the temperature range 167-170 °C be used in the extrusion machine to produce r-WoPPC filament. As a result, r-WoPPc filaments containing silane-treated wood dust have better mechanical properties and have a greater potential for usage in FDM applications.
  17. Omar R, Knight VF, Aziz Mohammed MA
    Malays Fam Physician, 2014;9(3):27-33.
    PMID: 26425302 MyJurnal
    Work-related ocular injuries and illnesses were among the major causes of job absenteeism. This study was conducted to determine if low vision rehabilitation was provided following work-related ocular problems among industrial workers in a developing country. This was a retrospective analysis of case records.
  18. Omar R, Knight VF, Mohammed Z, Tholasee GM
    MyJurnal
    While the prevalence of visually impaired children constitutes a small portion of the visually impaired population, it is important to determine whether the low vision services available are utilised by these children. This is important as previous studies have shown that children have a very high rate of successful low vision device use compared to adults. This was a cross sectional retrospective study. Fifty nine low vision clinic children records were evaluated. The results showed that 25.4% of the children were categorised as with moderate low vision, 30.5% with severe low vision and 40.7% were categorised as blind. The major causes of low vision were congenital cataract, congenital nystagmus, congenital glaucoma, macular degeneration and retinitis pigmentosa. Low vision rehabilitation for near work using magnifiers improved the vision of 30.5% of the low vision children. This finding suggests that 1/3 of low vision children could benefit from low vision rehabilitation. The low vision devices most commonly prescribed to the children in this study were stand magnifiers, hand-held magnifiers and spectacles. This study illustrates the key role of optometrists in the management of visual impairment in Malaysian children. It would appear that the establishment of low vision services in government hospitals using trained optometrists is a cost effective method of service delivery. Therefore more low vision children would have access to proper low vision rehabilitation and through that rehabilitation, their quality of life can be improved.
    Key words: children, low vision
    Study site: Klinik Penglihatan Terhad Pusat Perubatana, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
  19. Omar R, Hussin DA, Knight VF
    J Med Assoc Thai, 2012 Mar;95(3):412-7.
    PMID: 22550841
    Compare the performance of Lea Symbols and Sheridan Gardiner charts against the standard test chart used to determine reduced VA during vision screening among pre-schoolers.
  20. Omar R, Idris SS, Meng CK, Knight VF
    J Med Case Rep, 2012;6:316.
    PMID: 22992390
    A number of vision defects have been reported in association with albinism, such as photophobia, nystagmus and astigmatism. In many cases only prescription sunglasses are prescribed. In this report, the effectiveness of low-vision rehabilitation in albinism, which included prescription of multiple visual aids, is discussed.
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