Displaying publications 1 - 20 of 101 in total

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  1. Comparing groups using robust H statistic with adaptive trimmed mean
    Nur Faraidah Muhammad Di, Sharipah Soaad Syed Yahaya, Suhaida Abdullah
    Sains Malaysiana, 2014;43:643-648.
    An alternative robust method for testing the equality of central tendency measures was developed by integrating H Statistic with adaptive trimmed mean using hinge estimator, HQ. H Statistic is known for its ability to control Type I error rates and HQ is a robust location estimator. This robust estimator used asymmetric trimming technique, where it trims the tail of the distribution based on the characteristic of that particular distribution. To investigate on the performance (i.e. robustness) of the procedure, some variables were manipulated to create conditions which are known to highlight its strengths and weaknesses. Bootstrap method was used to test the hypothesis. The integration seemed to produce promising robust procedure that is capable of addressing the problem of violations to the assumptions. About 20% trimming is the appropriate amount of trimming for the procedure, where this amount is found to be robust in most conditions. This procedure was also proven to be robust as compared to the parametric (AN0vA) and non parametric (Kruskal-Wallis) methods.
    Matched MeSH terms: Prostheses and Implants
  2. Fulltext Review on Medical Implantable Antenna Technology and Imminent Research Challenges
    Soliman MM, Chowdhury MEH, Khandakar A, Islam MT, Qiblawey Y, Musharavati F, et al.
    Sensors (Basel), 2021 May 02;21(9).
    PMID: 34063296 DOI: 10.3390/s21093163
    Implantable antennas are mandatory to transfer data from implants to the external world wirelessly. Smart implants can be used to monitor and diagnose the medical conditions of the patient. The dispersion of the dielectric constant of the tissues and variability of organ structures of the human body absorb most of the antenna radiation. Consequently, implanting an antenna inside the human body is a very challenging task. The design of the antenna is required to fulfill several conditions, such as miniaturization of the antenna dimension, biocompatibility, the satisfaction of the Specific Absorption Rate (SAR), and efficient radiation characteristics. The asymmetric hostile human body environment makes implant antenna technology even more challenging. This paper aims to summarize the recent implantable antenna technologies for medical applications and highlight the major research challenges. Also, it highlights the required technology and the frequency band, and the factors that can affect the radio frequency propagation through human body tissue. It includes a demonstration of a parametric literature investigation of the implantable antennas developed. Furthermore, fabrication and implantation methods of the antenna inside the human body are summarized elaborately. This extensive summary of the medical implantable antenna technology will help in understanding the prospects and challenges of this technology.
    Matched MeSH terms: Prostheses and Implants*
  3. Fulltext Energy harvesting for the implantable biomedical devices: issues and challenges
    Hannan MA, Mutashar S, Samad SA, Hussain A
    Biomed Eng Online, 2014;13:79.
    PMID: 24950601 DOI: 10.1186/1475-925X-13-79
    The development of implanted devices is essential because of their direct effect on the lives and safety of humanity. This paper presents the current issues and challenges related to all methods used to harvest energy for implantable biomedical devices. The advantages, disadvantages, and future trends of each method are discussed. The concept of harvesting energy from environmental sources and human body motion for implantable devices has gained a new relevance. In this review, the harvesting kinetic, electromagnetic, thermal and infrared radiant energies are discussed. Current issues and challenges related to the typical applications of these methods for energy harvesting are illustrated. Suggestions and discussion of the progress of research on implantable devices are also provided. This review is expected to increase research efforts to develop the battery-less implantable devices with reduced over hole size, low power, high efficiency, high data rate, and improved reliability and feasibility. Based on current literature, we believe that the inductive coupling link is the suitable method to be used to power the battery-less devices. Therefore, in this study, the power efficiency of the inductive coupling method is validated by MATLAB based on suggested values. By further researching and improvements, in the future the implantable and portable medical devices are expected to be free of batteries.
    Matched MeSH terms: Prostheses and Implants*
  4. Topology optimisation of spinal interbody cage for reducing stress shielding effect
    Chuah HG, Abd Rahim I, Yusof MI
    Comput Methods Biomech Biomed Engin, 2010 Jun;13(3):319-26.
    PMID: 19927241 DOI: 10.1080/10255840903208189
    The stress shielding effect is an event in which the replacement implant limits the load transferred to bone and the ineffective stress in the vertebrae causes bony growth to cease. In the present study, a 3D finite element L4-L5 model was developed and subjected to a 1200 N compression preload. Five groups of muscle forces were applied on L4 under flexion-extension, lateral bending and axial rotation. Topology optimisation was employed for reducing the stress shielding effect by removing the ineffective material from the design domain. The optimised design was designed with polyaryletheretherketone (PEEK) titanium and cortical materials to encounter the shielding response. The stress responses show that the new design increased the stress magnitude by at least 17.10, 18.11 and 18.43% in 4 Nm of flexion-extension, lateral bending and axial rotation, respectively. In conclusion, the material factor did not significantly alter the stress magnitude, but volume was the key factor in reducing the stress shielding effect.
    Matched MeSH terms: Prostheses and Implants*
  5. Designing 3D prosthetic templates for maxillofacial defect rehabilitation: A comparative analysis of different virtual workflows
    Farook TH, Jamayet NB, Abdullah JY, Asif JA, Rajion ZA, Alam MK
    Comput Biol Med, 2020 03;118:103646.
    PMID: 32174323 DOI: 10.1016/j.compbiomed.2020.103646
    OBJECTIVE: To design and compare the outcome of commercial (CS) and open source (OS) software-based 3D prosthetic templates for rehabilitation of maxillofacial defects using a low powered personal computer setup.

    METHOD: Medical image data for five types of defects were selected, segmented, converted and decimated to 3D polygon models on a personal computer. The models were transferred to a computer aided design (CAD) software which aided in designing the prosthesis according to the virtual models. Two templates were designed for each defect, one by an OS (free) system and one by CS. The parameters for analyses were the virtual volume, Dice similarity coefficient (DSC) and Hausdorff's distance (HD) and were executed by the OS point cloud comparison tool.

    RESULT: There was no significant difference (p > 0.05) between CS and OS when comparing the volume of the template outputs. While HD was within 0.05-4.33 mm, evaluation of the percentage similarity and spatial overlap following the DSC showed an average similarity of 67.7% between the two groups. The highest similarity was with orbito-facial prostheses (88.5%) and the lowest with facial plate prosthetics (28.7%).

    CONCLUSION: Although CS and OS pipelines are capable of producing templates which are aesthetically and volumetrically similar, there are slight comparative discrepancies in the landmark position and spatial overlap. This is dependent on the software, associated commands and experienced decision-making. CAD-based templates can be planned on current personal computers following appropriate decimation.

    Matched MeSH terms: Prostheses and Implants*
  6. Fulltext Review on prophylactic antibiotics for dental patients with prosthetic joints
    Chai WL, Yong CK, Ngeow WC
    Ann Dent, 2003;10(1):22-26.
    MyJurnal
    Most prosthetic joint infections originate from wound contamination or haematogenous seeding from distant sites of infection. Bacteraemia may follow dental treatment but there is little evidence of it related to prosthetic joint infection. Nevertheless, controversy continues with regards to the effect of dental treatment in patients with prosthetic joints. This article reviews current English literature regarding the use of antibiotic prophylaxis in the dental management of patients with prosthetic joints. Routine antibiotic prophylaxis is not recommended for every patient with prosthetic joints when receiving dental treatments. However, antibiotic prophylaxis may be prescribed for high-risk groups with predisposing factors to infection when undergoing dental treatment with high risk of bacteraemia.
    Matched MeSH terms: Prostheses and Implants*
  7. Fulltext On the integral solutions of the diophantine equation x4 + y4 = z3
    Ismail, S., Mohd Atan, K.A.
    Pertanika Journal of Science & Technology, 2013;21(1):119-126.
    MyJurnal
    This paper is concerned with the existence, types and the cardinality of the integral solutions for
    diophantine equation
    4 4 3
    x y z + = where x , y and z are integers. The aim of this paper was to
    develop methods to be used in finding all solutions to this equation. Results of the study show the
    existence of infinitely many solutions to this type of diophantine equation in the ring of integers
    for both cases, x y = and x y ¹ . For the case when x y = , the form of solutions is given by
    3 3 4
    ( , , ) (4 , 4 ,8 ) x y z n n n = , while for the case when x y ¹ , the form of solutions is given by
    3 1 3 1 4 1
    ( , , ) ( , , )
    k k k
    x y z un vn n
    - - -
    = . The main result obtained is a formulation of a generalized method to find
    all the solutions for both types of diophantine equations.
    Matched MeSH terms: Prostheses and Implants
  8. Fulltext A biomechanical comparison between Taylor’s spatial frame and ilizarov external fixator
    Tan, B. B., Shanmugam, R., Chua, Y. P., Hossain, G., Saw, A.
    Malays Orthop J, 2014;8(2):35-39.
    MyJurnal
    Taylor’s spatial frame (TSF) and Ilizarov external fixators (IEF) are two circular external fixator commonly used to address complex deformity and fractures. There is currently no data available comparing the biomechanical properties of these two external fixators. This study looks into the mechanical characteristics of each system. TSF rings with 6 oblique struts, 4 tube connectors, 4 threaded rods, and 6 threaded rods were compared to a standard IEF rings with 4 threaded rods. Compression and torsional loading was performed to the frame as well as construct with Polyvinylchloride tubes. TSF rings with 4 tube connectors had the highest stiffness (3288 N/mm) while TSF rings with 6 struts was the least stiff. The situation was reversed for torsion where TSF rings with 6 oblique struts had the highest torsional stiffness (82.01 Nm/Degree) and frame Ilizarov rings with 4 threaded rods the least. Standard TSF construct of two ring with 6 oblique struts have better torsional stiffness and lower axial stiffness compared to the standard IEF.
    Matched MeSH terms: Prostheses and Implants
  9. Fulltext Development of power recovery circuit for bio-implantable stimulator
    Mokhalad Khaleel Alghrairi, Nasri Bin Sulaiman, Roslina Bt Mohd Sidek, Saad Mutashar
    Pertanika Journal of Science & Technology, 2017;25(102):87-96.
    MyJurnal
    This paper presents a modified design of low power recovery circuit in micro-system implanted device to stimulate the human nerve and muscle. The amplitude shift keying ASK was used to modulate data by using operating frequency 6.78MHz ISM industrial scientific medical band to be less invasive to tissue. The proposed system consists of an external part which has ASK modulator and class-E power amplifier with 94.5% efficiency. The internal part has half wave rectifier and voltage regulator to generate very stable 1.8VDC using 0.35um CMOS technology. The Orcad pspice 16.6 and MULTISIM 11 software were used to simulate the design of power recovery and class-E power amplifier respectively. The regulated voltage utilised to power the sub-electronic device implanted inside human body with very stable voltage even change implanted load resistance. The proposed system has 12.5%modulation index and low power consumption.
    Matched MeSH terms: Prostheses and Implants
  10. Fulltext Patient-specific frontal titanium mesh fabrication using a moulding technique
    Rengarajoo J, Harun RH, Royan SJ, Kohir S, Mamat MR
    Ann R Coll Surg Engl, 2022 Jul;104(7):556.
    PMID: 35174718 DOI: 10.1308/rcsann.2021.0299
    Matched MeSH terms: Prostheses and Implants
  11. Fulltext Modulation techniques for biomedical implanted devices and their challenges
    Hannan MA, Abbas SM, Samad SA, Hussain A
    Sensors (Basel), 2012;12(1):297-319.
    PMID: 22368470 DOI: 10.3390/s120100297
    Implanted medical devices are very important electronic devices because of their usefulness in monitoring and diagnosis, safety and comfort for patients. Since 1950s, remarkable efforts have been undertaken for the development of bio-medical implanted and wireless telemetry bio-devices. Issues such as design of suitable modulation methods, use of power and monitoring devices, transfer energy from external to internal parts with high efficiency and high data rates and low power consumption all play an important role in the development of implantable devices. This paper provides a comprehensive survey on various modulation and demodulation techniques such as amplitude shift keying (ASK), frequency shift keying (FSK) and phase shift keying (PSK) of the existing wireless implanted devices. The details of specifications, including carrier frequency, CMOS size, data rate, power consumption and supply, chip area and application of the various modulation schemes of the implanted devices are investigated and summarized in the tables along with the corresponding key references. Current challenges and problems of the typical modulation applications of these technologies are illustrated with a brief suggestions and discussion for the progress of implanted device research in the future. It is observed that the prime requisites for the good quality of the implanted devices and their reliability are the energy transformation, data rate, CMOS size, power consumption and operation frequency. This review will hopefully lead to increasing efforts towards the development of low powered, high efficient, high data rate and reliable implanted devices.
    Matched MeSH terms: Prostheses and Implants*
  12. Synthesis of nanosized hydroxyapatite powders
    Zarina O, Radzali O
    Med J Malaysia, 2004 May;59 Suppl B:160-1.
    PMID: 15468867
    Hydroxyapatite powder was mechanochemically synthesized from calcium pyrophosphate (Ca2P2O7) and calcium carbonate (CaCO3) using a solid-state reaction. The two powders were mixed in distilled water, milled for 8 hours, dried and calcined at 1100 degrees C for 1 hour. The phase(s) formed was analyzed by x-ray diffraction (XRD). It was found that hydroxyapatite was not the only one formed. This result will be used as the starting point to produce a single-phase hydroxyapatite in terms of excess hydroxyl group in a mechanochemical reaction.
    Matched MeSH terms: Prostheses and Implants*
  13. The influence of sintering temperature on the porosity and strength of porous hydroxyapatite ceramics
    Rusnah M, Andanastuti M, Idris B
    Med J Malaysia, 2004 May;59 Suppl B:158-9.
    PMID: 15468866
    The present paper reports on the influence of sintering temperature on the porosity and strength of porous hydroxyapatite (HA). HA powder was first prepared by the sol-gel precipitation method using calcium hydroxide and ortho-phosporic acid. The fine HA powder, measuring <50 microm was then mixed into a slurry with the addition of binder agent, being a mixture of sago and PVA. A small amount of sodium dodecyl sulphate was also used as a foaming agent. Porous HA samples were then prepared via slip casting technique. The surface morphology of the sintered samples was observed under scanning electron microscopy at 20 kV and the compositions were determined via SEM-EDX. A universal testing machine was used to determine the compaction strength of the sintered samples.
    Matched MeSH terms: Prostheses and Implants*
  14. Biomaterials research in Malaysia--development in facilities and expertise for in-vivo evaluation
    Khalid K
    Med J Malaysia, 2004 May;59 Suppl B:133-4.
    PMID: 15468854
    Matched MeSH terms: Prostheses and Implants*
  15. Prospects of plasma immersion ion implantation and deposition (PIlI & D) in the biomaterials field in Malaysia and south East Asia
    Mohamed MH
    Med J Malaysia, 2004 May;59 Suppl B:19-20.
    PMID: 15468798
    One of the emerging technologies in the area of plasma processing is plasma immersion ion implantation (PSII). The paper addresses the merits offered by the PSII technique especially in the area of biomaterial processing. Worldwide development status as well as the drive towards commercial applications is elaborated in an attempt to draw the attention to the importance of the process for Malaysia as well as south East Asia.
    Matched MeSH terms: Prostheses and Implants*
  16. Fulltext Characterization of the Fat Channel for Intra-Body Communication at R-Band Frequencies
    Asan NB, Hassan E, Shah JVSRM, Noreland D, Blokhuis TJ, Wadbro E, et al.
    Sensors (Basel), 2018 Aug 21;18(9).
    PMID: 30134629 DOI: 10.3390/s18092752
    In this paper, we investigate the use of fat tissue as a communication channel between in-body, implanted devices at R-band frequencies (1.7⁻2.6 GHz). The proposed fat channel is based on an anatomical model of the human body. We propose a novel probe that is optimized to efficiently radiate the R-band frequencies into the fat tissue. We use our probe to evaluate the path loss of the fat channel by studying the channel transmission coefficient over the R-band frequencies. We conduct extensive simulation studies and validate our results by experimentation on phantom and ex-vivo porcine tissue, with good agreement between simulations and experiments. We demonstrate a performance comparison between the fat channel and similar waveguide structures. Our characterization of the fat channel reveals propagation path loss of ∼0.7 dB and ∼1.9 dB per cm for phantom and ex-vivo porcine tissue, respectively. These results demonstrate that fat tissue can be used as a communication channel for high data rate intra-body networks.
    Matched MeSH terms: Prostheses and Implants*
  17. Transcatheter occlusion of native persistent ductus arteriosus using conventional Gianturco coils
    Alwi M, Kang LM, Samion H, Latiff HA, Kandavel G, Zambahari R
    Am J Cardiol, 1997 May 15;79(10):1430-2.
    PMID: 9165178 DOI: 10.1016/s0002-9149(97)00160-4
    Two hundred eleven patients with small- to moderate-sized native patent ductus arteriosus underwent closure using Gianturco coils, employing the transvenous multiple catheter approach. Short-term results showed a high rate of complete occlusion and a potential long-term complication of mild left pulmonary artery stenosis in a small number of patients.
    Matched MeSH terms: Prostheses and Implants*
  18. Advancement of Electrospun Nerve Conduit for Peripheral Nerve Regeneration: A Systematic Review (2016-2021)
    Lee SY, Thow SY, Abdullah S, Ng MH, Mohamed Haflah NH
    Int J Nanomedicine, 2022;17:6723-6758.
    PMID: 36600878 DOI: 10.2147/IJN.S362144
    Peripheral nerve injury (PNI) is a worldwide problem which hugely affects the quality of patients' life. Nerve conduits are now the alternative for treatment of PNI to mimic the gold standard, autologous nerve graft. In that case, with the advantages of electrospun micro- or nano-fibers nerve conduit, the peripheral nerve growth can be escalated, in a better way. In this systematic review, we focused on 39 preclinical studies of electrospun nerve conduit, which include the in vitro and in vivo evaluation from animal peripheral nerve defect models, to provide an update on the progress of the development of electrospun nerve conduit over the last 5 years (2016-2021). The physical characteristics, biocompatibility, functional and morphological outcomes of nerve conduits from different studies would be compared, to give a better strategy for treatment of PNI.
    Matched MeSH terms: Prostheses and Implants*
  19. Permeability study of cancellous bone and its idealised structures
    Syahrom A, Abdul Kadir MR, Harun MN, Öchsner A
    Med Eng Phys, 2015 Jan;37(1):77-86.
    PMID: 25523865 DOI: 10.1016/j.medengphy.2014.11.001
    Artificial bone is a suitable alternative to autografts and allografts, however their use is still limited. Though there were numerous reports on their structural properties, permeability studies of artificial bones were comparably scarce. This study focused on the development of idealised, structured models of artificial cancellous bone and compared their permeability values with bone surface area and porosity. Cancellous bones from fresh bovine femur were extracted and cleaned following an established protocol. The samples were scanned using micro-computed tomography (μCT) and three-dimensional models of the cancellous bones were reconstructed for morphology study. Seven idealised and structured cancellous bone models were then developed and fabricated via rapid prototyping technique. A test-rig was developed and permeability tests were performed on the artificial and real cancellous bones. The results showed a linear correlation between the permeability and the porosity as well as the bone surface area. The plate-like idealised structure showed a similar value of permeability to the real cancellous bones.
    Matched MeSH terms: Prostheses and Implants*
  20. Fulltext Controlling the degradation kinetics of porous iron by poly(lactic-co-glycolic acid) infiltration for use as temporary medical implants
    Yusop AH, Daud NM, Nur H, Kadir MR, Hermawan H
    Sci Rep, 2015;5:11194.
    PMID: 26057073 DOI: 10.1038/srep11194
    Iron and its alloy have been proposed as biodegradable metals for temporary medical implants. However, the formation of iron oxide and iron phosphate on their surface slows down their degradation kinetics in both in vitro and in vivo scenarios. This work presents new approach to tailor degradation behavior of iron by incorporating biodegradable polymers into the metal. Porous pure iron (PPI) was vacuum infiltrated by poly(lactic-co-glycolic acid) (PLGA) to form fully dense PLGA-infiltrated porous iron (PIPI) and dip coated into the PLGA to form partially dense PLGA-coated porous iron (PCPI). Results showed that compressive strength and toughness of the PIPI and PCPI were higher compared to PPI. A strong interfacial interaction was developed between the PLGA layer and the iron surface. Degradation rate of PIPI and PCPI was higher than that of PPI due to the effect of PLGA hydrolysis. The fast degradation of PIPI did not affect the viability of human fibroblast cells. Finally, this work discusses a degradation mechanism for PIPI and the effect of PLGA incorporation in accelerating the degradation of iron.
    Matched MeSH terms: Prostheses and Implants*
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