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  1. Koh CT, Tonsomboon K, Oyen ML
    Interface Focus, 2019 Oct 06;9(5):20190012.
    PMID: 31485308 DOI: 10.1098/rsfs.2019.0012
    Amnion is a membrane that surrounds and structurally protects the developing fetus during pregnancy. The rupture of amniotic membranes prior to both normal and preterm deliveries involves stretch forces acting on a biochemically triggered weak zone of the membranes. Fracture toughness is an important mechanical property describing how the membranes containing a defect resist fracture, but this property has never been investigated in amniotic membranes. In this work, the fracture toughness of many samples cut from four pieces of amniotic membrane from different mothers was examined by uniaxial and pure shear (mode I) fracture tests. The measurement was checked for dependence on the sample geometry and notch length. Results from the uniaxial tensile test show J-shaped stress-strain curves and confirm that the amniotic membrane is a nonlinear material. The measured fracture toughness of four amniotic membranes ranged from 0.96 ± 0.11 to 1.83 ± 0.18 kJ m-2. Despite considering the effect of the presence of the defect on mechanical property measurement, similar fracture behaviour was observed for pre-notched and unnotched specimens, indicating that the membranes were extremely tolerant to defects. This defect-tolerant characteristic provides insight into the understanding of fetal membrane rupture.
  2. Butcher AL, Koh CT, Oyen ML
    J Mech Behav Biomed Mater, 2017 May;69:412-419.
    PMID: 28208112 DOI: 10.1016/j.jmbbm.2017.02.007
    Electrospinning is a simple and efficient process for producing sub-micron fibres. However, the process has many variables, and their effects on the non-woven mesh of fibres is complex. In particular, the effects on the mechanical properties of the fibre meshes are poorly understood. This paper conducts a parametric study, where the concentration and bloom strength of the gelatin solutions are varied, while all electrospinning process parameters are held constant. The effects on the fibrous meshes are monitored using scanning electron microscopy and mechanical testing under uniaxial tension. Mesh mechanical properties are relatively consistent, despite changes to the solutions, demonstrating the robustness of electrospinning. The gel strength of the solution is shown to have a statistically significant effect on the morphology, stiffness and strength of the meshes, while the fibre diameter has surprisingly little influence on the stiffness of the meshes. This experimental finding is supported by finite element analysis, demonstrating that the stiffness of the meshes is controlled by the volume fraction, rather than fibre diameter. Our results demonstrate the importance of understanding how electrospinning parameters influence the pore size of the meshes, as controlling fibre diameter alone is insufficient for consistent mechanical properties.
  3. Yusoff S, Koh CT, Mohd Aminuddin MY, Krishnasamy M, Suhaila MZ
    East Asian Arch Psychiatry, 2013 Sep;23(3):91-101.
    PMID: 24088402
    The Malaysian Clinical Practice Guidelines (CPG) for Management of Dementia (second edition) was launched in April 2010 by the Ministry of Health Malaysia. A training programme for the management of dementia, involving all categories of staff working at primary and secondary centres, was implemented to ensure that care delivery for people with dementia was in accordance with the guidelines. The study aimed to look into improving knowledge and understanding of dementia following training, and to evaluate the effectiveness of the training programme using a clinical audit indicator recommended in the guidelines.
  4. Khoo W, Chung SM, Lim SC, Low CY, Shapiro JM, Koh CT
    Data Brief, 2019 Dec;27:104718.
    PMID: 31763388 DOI: 10.1016/j.dib.2019.104718
    Data in this article are supplementary to the corresponding research article [1]. Morphological features of homogeneous and graded nanofibrous electrospun gelatin scaffolds were observed using scanning electron microscopy. Microstructural properties including fiber diameter and pore size were determined via image analysis, using ImageJ. Uniaxial tensile and fracture tests were performed on both homogeneous and graded scaffolds using a universal testing machine. Stress-strain curves of all scaffolds are presented. Computing software, MATLAB, was used to design fibrous networks with thickness-dependent density and alignment gradients (DAG). Finite element analysis software, Abaqus, was used to determine the effect of the number of layers on the fracture properties of DAG multilayer scaffolds.
  5. Koh CT, Ghazi HF, Ahmad MI, Abdul Samad N, Lai KEY, Ismail NF, et al.
    Health Serv Res Manag Epidemiol, 2016 May 5;3:2333392816643720.
    PMID: 28462275 DOI: 10.1177/2333392816643720
    OBJECTIVES: To assess the knowledge, attitude, and practice of parents regarding antibiotic usage for treating upper respiratory tract infection (URTI) among children.
    METHODS: A cross-sectional study was conducted among 320 randomly selected parents attending a primary health clinic using self-administered questionnaires.
    RESULTS: About two-thirds (69.1%) of the parents had poor knowledge level. Only 25.2% and 21.6% of the parents could correctly identify amoxicillin and penicillin as the treatment of children's URTI. However, about two-thirds (67.5%) of the parents were aware of the antibiotic resistance caused by overuse of antibiotics. A significant association was noted between the father's and mother's educational level and family income with the knowledge level. Only mother's educational level depicted a significant association with the attitude.
    CONCLUSION: The knowledge of parents regarding antibiotic usage for URTI was poor. More numbers of health promotions and educational campaigns are required to help parents understand about antibiotic usage.
    Study site: Primary care clinic, Bandar Tasik Selatan, Kuala Lumpur, Malaysia
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