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Identification of competencies for Malaysian occupational safety and health professionals

Daud R, Ismail M, Omar Z

Ind Health, 2010;48(6):824-34.
PMID: 20616464

Competencies of occupational safety and health (OSH) professionals have become a concern due to the significance of safety management in the field of safety engineering. The purpose of this article is to identify competencies needed by OSH professionals. These competencies are required by professionals in administrating and enforcing legislations related to OSH in Malaysia. This study used Delphi technique in three rounds of data collection. The benefits of this research approach are the use of experts in gaining opinions without time and geographical restraints. The results show 25 generic competencies with combinations of cognitive, interpersonal and intrapersonal competencies and 33 functional or specific competencies including knowledge and skills needed by OSH professionals. Both generic and functional competencies are also divided into threshold and differentiating competencies that would be used to differentiate average and excellent performance of OSH professionals.
Fulltext Maxillofacial injuries associated with intimate partner violence in women

Saddki N, Suhaimi AA, Daud R

BMC Public Health, 2010;10:268.
PMID: 20492720 DOI: 10.1186/1471-2458-10-268

The facial region has been the most common site of injury following violent episodes. The purpose of this study was to determine the prevalence and pattern of maxillofacial injuries associated with intimate partner violence (IPV) in women treated at a single facility in Malaysia.
Fulltext Experimental Analysis of Fabricated Synthetic Midthoracic Paediatric Spine as Compared to the Porcine Spine Based on Range of Motion (ROM)

Muhayudin NA, Basaruddin KS, Daud R, McEvoy F, Tansey

Appl Bionics Biomech, 2021;2021:2799415.
PMID: 34608402 DOI: 10.1155/2021/2799415

The present study is aimed at investigating the mechanical behaviour of fabricated synthetic midthoracic paediatric spine based on range of motion (ROM) as compared to porcine spine as the biological specimen. The main interest was to ensure that the fabricated synthetic model could mimic the biological specimen behaviour. The synthetic paediatric spine was designed as a 200% scaled-up model to fit into the Bionix Servohydraulic spine simulator. Biomechanical tests were conducted to measure the ROM and nonlinearity of sigmoidal curves at six degrees of freedom (DOF) with moments at ±4 Nm before the specimens failed. Results were compared with the porcine spine (biological specimen). The differences found between the lateral bending and axial rotation of synthetic paediatric spine as compared to the porcine spine were 18% and 3%, respectively, but was still within the range. Flexion extension of the synthetic spine is a bit stiff in comparison of porcine spine with 45% different. The ROM curves of the synthetic paediatric spine exhibited nonlinearities for all motions as the measurements of neutral zone (NZ) and elastic zone (EZ) stiffness were below "1." Therefore, it showed that the proposed synthetic paediatric spine behaved similarly to the biological specimen, particularly on ROM.
Fulltext Finite Element Modelling of a Synthetic Paediatric Spine for Biomechanical Investigation

Muhayudin NA, Basaruddin KS, Ijaz MF, Daud R

Materials (Basel), 2023 Jun 21;16(13).
PMID: 37444827 DOI: 10.3390/ma16134514

Studies on paediatric spines commonly use human adult or immature porcine spines as specimens, because it is difficult to obtain actual paediatric specimens. There are quite obvious differences, such as geometry, size, bone morphology, and orientation of facet joint for these specimens, compared to paediatric spine. Hence, development of synthetic models that can behave similarly to actual paediatric spines, particularly in term of range of motion (ROM), could provide a significant contribution for paediatric spine research. This study aims to develop a synthetic paediatric spine using finite element modelling and evaluate the reliability of the model by comparing it with the experimental data under certain load conditions. The ROM of the paediatric spine was measured using a validated FE model at ±0.5 Nm moment in order to determine the moment required by the synthetic spine to achieve the same ROM. The results showed that the synthetic spine required two moments, ±2 Nm for lateral-bending and axial rotation, and ±3 Nm for flexion-extension, to obtain the paediatric ROM. The synthetic spine was shown to be stiffer in flexion-extension but more flexible in lateral bending than the paediatric FE model, possibly as a result of the intervertebral disc's simplified shape and the disc's weak bonding with the vertebrae. Nevertheless, the synthetic paediatric spine has promising potential in the future as an alternative paediatric spine model for biomechanical investigation of paediatric cases.
Three-dimensional morphometric study of the trapezium shape of the trochlea tali

Daud R, Abdul Kadir MR, Izman S, Md Saad AP, Lee MH, Che Ahmad A

J Foot Ankle Surg, 2013 Jul-Aug;52(4):426-31.
PMID: 23623302 DOI: 10.1053/j.jfas.2013.03.007

The trapezium shape of the talar dome limits the use of 2-dimensional plain radiography for morphometric assessment because only 2 of the 4 required parameters can be measured. We used computed tomography data to measure the 4 morphologic parameters of the trochlea tali: anterior width, posterior width, trochlea tali length, and angle of trapezium shape. A total of 99 subjects underwent computed tomography scanning, and the left and right talus bones were both virtually modeled in 3 dimensions. The 4 morphologic parameters were measured 3 times each to obtain the intraclass correlation, and analysis of variance was used to check for any significant differences between the repeated measurements. The average intraclass correlation coefficient for the measurements for 2 to 3 trials was 0.94 ± 0.04. Statistical analyses were performed on the data from all 198 talus bones using SAS software, comparing male and female and left and right bones. All 4 morphometric values were greater in the male group. No significant differences were found between the left and right talus bones. A strong positive correlation was observed between the trochlea tali length and the anterior width. The angle of trapezium shape showed no correlation with the other 3 parameters. The measurements were compared with the dimensions of the current talar components of 4 total ankle arthroplasty implants. However, most of them did not perfectly match the trapezium shape of the talus from our population. We successfully analyzed the trapezium shape of the trochlea tali using reliable virtual 3-dimensional measurements. Compared with other published reports, our study showed a relatively smaller dimension of the trochlea tali than the European counterparts.
A pilot study of reference vibrotactile perception thresholds on the fingertip obtained with Malaysian healthy people using ISO 13091-1 equipment

Daud R, Maeda S, Kameel NN, Ripin MY, Bakrun N, Md Zein R, et al.

Ind Health, 2004 Apr;42(2):189-95.
PMID: 15128168

The purpose of this paper is to clarify the reference vibrotactile perception thresholds (VPT) for healthy people in Malaysia. The measurement equipment standard, ISO 13091-1, of the vibrotactile perception thresholds for the assessment of nerve dysfunction and the analysis and interpretation of measurements at the fingertips standard, ISO 13091-2, were published in ISO/TC108/SC4/WG8 on 2001 and 2003 individually. In the ISO 13091-2 standard, the reference VPT data were obtained from few research papers. Malaysian people's VPT data don't include to this standard. In Malaysia, when the VPT is using to diagnose of the hand-arm vibration syndrome, the reference VPT data need to compare with the worker's ones. But, Malaysia does not have the reference VPT data yet. So, in this paper, the VPT was measured by using ISO 13091-1 standard equipment to obtain the reference data for Malaysian people. And these data were compared with the ISO reference data on the ISO 13091-2 standard. From the comparison of these data, it was clear that the Malaysian healthy people's VPT data were consistent with the reference data of the ISO 13091-2 standard.
Stability Analysis of Plate-Screw Fixation for Femoral Midshaft Fractures

Basirom I, Daud R, Ijaz MF, Rojan MA, Basaruddin KS

Materials (Basel), 2023 Aug 30;16(17).
PMID: 37687652 DOI: 10.3390/ma16175958

An understanding of the biomechanical characteristics and configuration of flexible and locked plating in order to provide balance stability and flexibility of implant fixation will help to construct and promote fast bone healing. The relationship between applied loading and implantation configuration for best bone healing is still under debate. This study aims to investigate the relationship between implant strength, working length, and interfragmentary strain (εIFM) on implant stability for femoral midshaft transverse fractures. The transverse fracture was fixed with a fragment locking compression plate (LCP) system. Finite element analysis was performed and subsequently characterised based on compression loading (600 N up to 900 N) and screw designs (conventional and locking) with different penetration depths (unicortical and bicortical). Strain theory was used to evaluate the stability of the model. The correlation of screw configuration with screw type shows a unicortical depth for both types (p < 0.01) for 700 N and 800 N loads and (p < 0.05) for configurations 134 and 124. Interfragmentary strain affected only the 600 N load (p < 0.01) for the bicortical conventional type (group BC), and the screw configurations that were influenced were 1234 and 123 (p < 0.05). The low steepness of the slope indicates the least εIFM for the corresponding biomechanical characteristic in good-quality stability. A strain value of ≤2% promotes callus formation and is classified as absolute stability, which is the minimum required value for the induction of callus and the maximum value that allows bony bridging. The outcomes have provided the correlation of screw configuration in femoral midshaft transverse fracture implantation which is important to promote essential primary stability.
Assessment of stress shielding around a dental implant for variation of implant stiffness and parafunctional loading using finite element analysis

Ishak MI, Daud R, Noor SNFM, Khor CY, Roslan H

Acta Bioeng Biomech, 2022;24(3):147-159.
PMID: 38314490

PURPOSE: The aim of this study was to evaluate the mechanical stimuli transfer at the bone-implant interface via stress and strain energy density transfer parameters. This study also aimed to investigate the effect of different implant stiffness and parafunctional loading values on the defined mechanical stimuli transfer from the implant to the surrounding bone.
METHODS: A three-dimensional finite element model of two-piece threaded dental implant with internal hexagonal connection and mandibular bone block was constructed. Response surface method through face-centred central composite design was applied to examine the influence of two independent factors variables using three levels. The analysis model was fitted to a second-order polynomial equation to determine the response values.
RESULTS: The results showed that the implant stiffness was more effective than the horizontal load value in increasing the stress and strain energy density transfers. The interaction between both factors was significant in decreasing the likelihood of bone resorption. Decreasing the implant stiffness and horizontal load value led to the increased stress transfer and unexpected decrease in the strain energy density, except at the minimum level of the horizontal load. The increase in the implant stiffness and horizontal load value (up to medium level) have increased the strain energy transfer to the bone.
CONCLUSIONS: The stress and strain energy density were transferred distinctively at the bone-implant interface. The role of both implant stiffness and parafunctional loading is important and should be highlighted in the preoperative treatment planning and design of dental implant.