Displaying publications 1 - 20 of 26 in total

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  1. Omar R, Wan Abdul WMH, Knight VF
    BMC Public Health, 2019 Jun 13;19(Suppl 4):543.
    PMID: 31196018 DOI: 10.1186/s12889-019-6865-3
    BACKGROUND: School children are considered a high-risk group for visual impairment because uncorrected refractive errors and problems such as amblyopia can seriously affect their learning abilities and their physical and mental development. There are many studies reporting the prevalence of refractive errors among school children of different ethnic groups in Malaysia, however, studies concerning the prevalence of refractive errors among indigenous or Orang Asli children are very limited. Therefore, the objective of this study was to determine the prevalence and causes of visual impairment among Orang Asli children.

    METHODS: One hundred ten Orang Asli children aged 7 to 12 years old in Negeri Sembilan, Malaysia were selected. 51% of these children were boys while the remainders were girls. They underwent visual acuity test, cover test, Hirschberg's test, ocular external assessment and ophthalmoscopy. Children who failed the vision screening were then referred for further eye examination.

    RESULTS: Of these 110 Orang Asli children, 46 failed the vision screening and subsequently 45 of them were confirmed to have visual problems (40.9% of the total subjects). The main cause of visual impairment in this study was refractive error (34.5% of the total subjects) where the main refractive error found was hyperopia (28.2%) followed by amblyopia (2.7%), strabismus (1.8%) and ocular abnormalities (1.8%).

    CONCLUSION: Hence, vision screening and a comprehensive eye examination is very important and needs to be done on all Orang Asli children so that any visual problems can be detect at an early stage to avoid the development of learning difficulties among these already disadvantaged children.

  2. Omar R, Rahman MH, Knight VF, Mustaphal M, Mohammed Z
    BMC Res Notes, 2014;7:667.
    PMID: 25245590 DOI: 10.1186/1756-0500-7-667
    BACKGROUND: Vision impairment associated with diabetic retinopathy, is well known and low vision rehabilitation is always recommended. In this report, the importance of objective measure of mental health and quality of life screening in diabetic retinopathy low-vision assessment is discussed.
    CASE PRESENTATION: We describe the case of a 43-year-old Asian female who has mild vision impairment due to tractional retinal detachment secondary to diabetic retinopathy and how mental health screening and quality of life screening during low vision rehabilitation can improve in the management of this patient.
    CONCLUSION: Although vision impairment was mild, the psychological impact was enormous and affected her quality of life substantially. This case report illustrates that recognition of the mental health and quality of life impact on visual impairment is critical to the rehabilitation management of low vision patients with diabetic retinopathy.
  3. Omar R, Anan NS, Azri IA, Majumder C, Knight VF
    BMJ Open, 2022 Jan 31;12(1):e048965.
    PMID: 35105614 DOI: 10.1136/bmjopen-2021-048965
    OBJECTIVE: The aim of this study is to determine the characteristics of eye injuries, medical costs and return-to-work status among industrial workers to provide better vision rehabilitative services.

    SETTING: Nationwide data from the Social Security Organisation (SOCSO) of Malaysia.

    PARTICIPANTS: A stratified random sample of workers registered with the SOCSO of Malaysia with documentation of eye injury.

    PRIMARY AND SECONDARY OUTCOME MEASURES: Characteristics of eye injuries and medical costs related to eye injury (primary) and return-to-work status (secondary).

    RESULTS: A total of 884 from 8861 case files workplace accidents involving eye injury registered with Social Security Services (SOCSO) were identified. The mean age was 35±10 years and the highest incidence of work-related eye injury occurred in the age group 30-39 years and among Malay ethnics. Males are affected more than females' workers. The highest cause of eye injury was the impact from a moving object excluding falling objects (89.2%) and anterior segment injuries occurred more than posterior segment injuries. The total direct and Indirect medical cost was RM1 108 098.00 (US$316 599.40) and RM4 150 140.00 (US$1 185 754.20) for 884 cases.

    CONCLUSION: The majority of workers suffered from the low level of eye injury. A significant relationship was found between the severity of eye injury and employee work status. The indirect cost of medical and vision rehabilitation was higher than the direct cost. Awareness and vision rehabilitation programmes at the workplace need to be addressed for better prevention and rehabilitative service.

  4. Omar R, Kuan YM, Zuhairi NA, Manan FA, Knight VF
    Int J Ophthalmol, 2017;10(9):1460-1464.
    PMID: 28944208 DOI: 10.18240/ijo.2017.09.20
    AIM: To compare visual efficiency, specifically accom-modation, vergence, and oculomotor functions among athletes and non-athletes.

    METHODS: A cross-sectional study on sports vision screening was used to evaluate the visual skills of 214 elementary students (107 athletes, 107 non-athletes), aged between 13 and 16y. The visual screening assessed visual parameters such as ocular motor alignment, accommodation, and vergence functions.

    RESULTS: Mean visual parameters were compared between age-group matched athletes (mean age 14.82±0.98y) and non-athletes (mean age 15.00±1.04y). The refractive errors of all participants were corrected to maximal attainable best corrected visual acuity of logMAR 0.0. Accommodation function assessment evaluated amplitude of accommodation and accommodation facility. Vergence functions measured the near point of convergence, vergence facility, and distance fusional vergence at break and recovery point. Ocular motor alignment was not statistically significant between both groups. Athletes had a statistically significant amplitude of accommodation for both the right eye (t=2.30, P=0.02) and the left eye (t=1.99, P=0.05). Conversely, non-athletes had better accommodation facility (t=-2.54, P=0.01) and near point of convergence (t=4.39, P<0.001) when compared to athletes. Vergence facility was found to be better among athletes (t=2.47, P=0.01). Nevertheless, non-athletes were significantly better for both distance negative and positive fusional vergence.

    CONCLUSION: Although the findings are still inconclusive as to whether athletes had superior visual skills as compared to non-athletes, it remains important to identify and elucidate the key visual skills needed by athletes in order for them to achieve higher performance in their sports.

  5. Omar MN, Rahman RNZRA, Noor NDM, Latip W, Knight VF, Ali MSM
    J Biomol Struct Dyn, 2024 Mar 31.
    PMID: 38555730 DOI: 10.1080/07391102.2024.2331093
    Aminopeptidase P (APPro) is a crucial metalloaminopeptidase involved in amino acid cleavage from peptide N-termini, playing essential roles as versatile biocatalysts with applications ranging from pharmaceuticals to industrial processes. Despite acknowledging its potential for catalysis in lower temperatures, detailed molecular basis and biotechnological implications in cold environments are yet to be explored. Therefore, this research aims to investigate the molecular mechanisms underlying the cold-adapted characteristics of APPro from Pseudomonas sp. strain AMS3 (AMS3-APPro) through a detailed analysis of its structure and dynamics. In this study, structure analysis and molecular dynamics (MD) simulation of a predicted model of AMS3-APPro has been performed at different temperatures to assess structural flexibility and thermostability across a temperature range of 0-60 °C over 100 ns. The MD simulation results revealed that the structure were able to remain stable at low temperatures. Increased temperatures present a potential threat to the overall stability of AMS3-APPro by disrupting the intricate hydrogen bond networks crucial for maintaining structural integrity, thereby increasing the likelihood of protein unfolding. While the metal binding site at the catalytic core exhibits resilience at higher temperatures, highlighting its local structural integrity, the overall enzyme structure undergoes fluctuations and potential denaturation. This extensive structural instability surpasses the localized stability observed at the metal binding site. Consequently, these assessments offer in-depth understanding of the cold-adapted characteristics of AMS3-APPro, highlighting its capability to uphold its native conformation and stability in low-temperature environments. In summary, this research provides valuable insights into the cold-adapted features of AMS3-APPro, suggesting its efficient operation in low thermal conditions, particularly relevant for potential biotechnological applications in cold environments.Communicated by Ramaswamy H. Sarma.
  6. Gnanou JV, Caszo BA, Khalil KM, Abdullah SL, Knight VF, Bidin MZ
    PMID: 26155596 DOI: 10.1186/s40200-015-0183-9
    BACKGROUND: Adiponectin is a hormone secreted by adipocytes during the fasting phase of the fast-fed cycle. Ramadan fasting involves prolonged fasting for up to twelve hours and thus could lead to increased secretion of adiponectin by adipocytes. However, studies on the role of adiponectin on glucose and body weight homeostasis during Ramadan fasting is still a matter of controversy. Thus the specific aim of this study was to assess the effect of fasting during Ramadan on the adiponectin levels, body weight and glucose homeostasis in healthy male Malaysian subjects.

    METHODS: Twenty healthy male (19-23 years) Muslim subjects were followed up during the fasting month of Ramadan. Anthropometry and blood samples were taken one week before and during the fourth week of fasting. Plasma glucose, insulin and adiponectin were estimated and insulin sensitivity indices were estimated using the Homeostasis Model Assessment.

    RESULTS: Subjects experienced a significant decrease in body weight (2.4 %, p 

  7. 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.
  8. 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.
  9. 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
  10. 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.
  11. 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.
  12. 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.
  13. 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.
  14. 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.

  15. 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.
  16. 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.
  17. 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.
  18. 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.
  19. 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.
  20. 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.].
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