Displaying publications 41 - 60 of 116 in total

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  1. Fulltext The use of fiber Bragg grating sensors in biomechanics and rehabilitation applications: the state-of-the-art and ongoing research topics
    Al-Fakih E, Abu Osman NA, Mahamd Adikan FR
    Sensors (Basel), 2012 Sep 25;12(10):12890-926.
    PMID: 23201977 DOI: 10.3390/s121012890
    In recent years, fiber Bragg gratings (FBGs) are becoming increasingly attractive for sensing applications in biomechanics and rehabilitation engineering due to their advantageous properties like small size, light weight, biocompatibility, chemical inertness, multiplexing capability and immunity to electromagnetic interference (EMI). They also offer a high-performance alternative to conventional technologies, either for measuring a variety of physical parameters or for performing high-sensitivity biochemical analysis. FBG-based sensors demonstrated their feasibility for specific sensing applications in aeronautic, automotive, civil engineering structure monitoring and undersea oil exploration; however, their use in the field of biomechanics and rehabilitation applications is very recent and its practicality for full-scale implementation has not yet been fully established. They could be used for detecting strain in bones, pressure mapping in orthopaedic joints, stresses in intervertebral discs, chest wall deformation, pressure distribution in Human Machine Interfaces (HMIs), forces induced by tendons and ligaments, angles between body segments during gait, and many others in dental biomechanics. This article aims to provide a comprehensive overview of all the possible applications of FBG sensing technology in biomechanics and rehabilitation and the status of ongoing researches up-to-date all over the world, demonstrating the FBG advances over other existing technologies.
  2. Polycaprolactone/starch composite: Fabrication, structure, properties, and applications
    Ali Akbari Ghavimi S, Ebrahimzadeh MH, Solati-Hashjin M, Abu Osman NA
    J Biomed Mater Res A, 2015 Jul;103(7):2482-98.
    PMID: 25407786 DOI: 10.1002/jbm.a.35371
    Interests in the use of biodegradable polymers as biomaterials have grown. Among the different polymeric composites currently available, the blend of starch and polycaprolactone (PCL) has received the most attention since the 1980s. Novamont is the first company that manufactured a PCL/starch (SPCL) composite under the trademark Mater-Bi®. The properties of PCL (a synthetic, hydrophobic, flexible, expensive polymer with a low degradation rate) and starch (a natural, hydrophilic, stiff, abundant polymer with a high degradation rate) blends are interesting because of the composite components have completely different structures and characteristics. PCL can adjust humidity sensitivity of starch as a biomaterial; while starch can enhance the low biodegradation rate of PCL. Thus, by appropriate blending, SPCL can overcome important limitations of both PCL and starch components and promote controllable behavior in terms of mechanical properties and degradation which make it suitable for many biomedical applications. This article reviewed the different fabrication and modification methods of the SPCL composite; different properties such as structural, physical, and chemical as well as degradation behavior; and different applications as biomaterials.
  3. Fulltext A comparison in mechanical properties of cermets of calcium silicate with Ti-55Ni and Ti-6Al-4V alloys for hard tissues replacement
    Ataollahi Oshkour A, Pramanik S, Shirazi SF, Mehrali M, Yau YH, Abu Osman NA
    ScientificWorldJournal, 2014;2014:616804.
    PMID: 25538954 DOI: 10.1155/2014/616804
    This study investigated the impact of calcium silicate (CS) content on composition, compressive mechanical properties, and hardness of CS cermets with Ti-55Ni and Ti-6Al-4V alloys sintered at 1200°C. The powder metallurgy route was exploited to prepare the cermets. New phases of materials of Ni16Ti6Si7, CaTiO3, and Ni31Si12 appeared in cermet of Ti-55Ni with CS and in cermet of Ti-6Al-4V with CS, the new phases Ti5Si3, Ti2O, and CaTiO3, which were emerged during sintering at different CS content (wt%). The minimum shrinkage and density were observed in both groups of cermets for the 50 and 100 wt% CS content, respectively. The cermets with 40 wt% of CS had minimum compressive Young's modulus. The minimum of compressive strength and strain percentage at maximum load were revealed in cermets with 50 and 40 wt% of CS with Ti-55Ni and Ti-6Al-4V cermets, respectively. The cermets with 80 and 90 wt% of CS showed more plasticity than the pure CS. It concluded that the composition and mechanical properties of sintered cermets of Ti-55Ni and Ti-6Al-4V with CS significantly depend on the CS content in raw cermet materials. Thus, the different mechanical properties of the cermets can be used as potential materials for different hard tissues replacements.
  4. A comparison of pressure distributions between two types of sockets in a bulbous stump
    Gholizadeh H, Abu Osman NA, Eshraghi A, Arifin N, Chung TY
    Prosthet Orthot Int, 2016 Aug;40(4):509-16.
    PMID: 25583929 DOI: 10.1177/0309364614564022
    BACKGROUND: This article describes a total surface bearing prosthetic socket for a patient (25-year-old female) with a bulbous stump.

    CASE DESCRIPTION AND METHODS: The subject had unstable excessive soft tissue at the distal end of the residuum. After 2 years of prosthetic use, she experienced several problems, including pain in the residual limb and knee joint. Pressure distribution was evaluated during ambulation. We also designed a total surface bearing socket with Velcro as suspension system to distribute the load evenly on the residual limb, and to facilitate donning procedure.

    FINDINGS AND OUTCOMES: The main site of weight bearing in the old prosthesis (patellar tendon bearing) was anterior proximal region of the residual limb, especially the patellar tendon. The pressure was almost 10 times higher than the distal region during level walking. Pressures were distributed more evenly with the total surface bearing socket design, and the donning was much easier.

    CONCLUSION: Pressure distribution within the socket could be affected by socket design and suspension system. Using the total surface bearing socket and Velcro as suspension system might facilitate donning of prosthesis and reduce traction at the end of residual limb during the swing phase of gait.

    CLINICAL RELEVANCE: Proper socket design and suspension system based on the amputees' need can facilitate rehabilitation process and lead to the amputee's satisfaction. The pressure is distributed more uniformly over the residual limb by the total surface bearing socket compared to the patellar tendon bearing socket for lower limb amputees with unusual stump shape.

  5. Fulltext Comparison of various functionally graded femoral prostheses by finite element analysis
    Oshkour AA, Talebi H, Shirazi SF, Bayat M, Yau YH, Tarlochan F, et al.
    ScientificWorldJournal, 2014;2014:807621.
    PMID: 25302331 DOI: 10.1155/2014/807621
    This study is focused on finite element analysis of a model comprising femur into which a femoral component of a total hip replacement was implanted. The considered prosthesis is fabricated from a functionally graded material (FGM) comprising a layer of a titanium alloy bonded to a layer of hydroxyapatite. The elastic modulus of the FGM was adjusted in the radial, longitudinal, and longitudinal-radial directions by altering the volume fraction gradient exponent. Four cases were studied, involving two different methods of anchoring the prosthesis to the spongy bone and two cases of applied loading. The results revealed that the FG prostheses provoked more SED to the bone. The FG prostheses carried less stress, while more stress was induced to the bone and cement. Meanwhile, less shear interface stress was stimulated to the prosthesis-bone interface in the noncemented FG prostheses. The cement-bone interface carried more stress compared to the prosthesis-cement interface. Stair climbing induced more harmful effects to the implanted femur components compared to the normal walking by causing more stress. Therefore, stress shielding, developed stresses, and interface stresses in the THR components could be adjusted through the controlling stiffness of the FG prosthesis by managing volume fraction gradient exponent.
  6. Fulltext Effect of intra-articular hyaluronic injection on postural stability and risk of fall in patients with bilateral knee osteoarthritis
    Khalaj N, Abu Osman NA, Mokhtar AH, George J, Abas WA
    ScientificWorldJournal, 2014;2014:815184.
    PMID: 25136689 DOI: 10.1155/2014/815184
    Knee osteoarthritis is a common cause of disability which influences the quality of life. It is associated with impaired knee joint proprioception, which affects postural stability. Postural stability is critical for mobility and physical activities. Different types of treatment including nonsurgical and surgical are used for knee osteoarthritis. Hyaluronic acid injection is a nonsurgical popular treatment used worldwide. The aim of this study was to demonstrate the effect of hyaluronic acid injections on postural stability in individuals with bilateral knee osteoarthritis. Fifty patients aged between 50 and 70 years with mild and moderate bilateral knee osteoarthritis participated in our study. They were categorized into treatment (n = 25) and control (n = 25) groups. The treatment group received five weekly hyaluronic acid injections for both knees, whereas the control group did not receive any treatment. Postural stability and fall risk were assessed using the Biodex Stability System and clinical "Timed Up and Go" test. All the participants completed the study. The treatment group showed significant decrease in postural stability and fall risk scores after five hyaluronic acid injections. In contrast, the control group showed significant increase. This study illustrated that five intra-articular hyaluronic acid injections could significantly improve postural stability and fall risk in bilateral knee osteoarthritis patients. This trial is registered with: NCT02063373.
  7. Fulltext Comparative study between Dermo, Pelite, and Seal-In X5 liners: effect on patient's satisfaction and perceived problems
    Ali S, Abu Osman NA, Arifin N, Gholizadeh H, Abd Razak NA, Abas WA
    ScientificWorldJournal, 2014;2014:769810.
    PMID: 25184154 DOI: 10.1155/2014/769810
    This study aimed to compare the effect of satisfaction and perceived problems between Pelite, Dermo with shuttle lock, and Seal-In X5 liners on the transtibial amputees.
  8. Fulltext Development of an air pneumatic suspension system for transtibial prostheses
    Pirouzi G, Abu Osman NA, Oshkour AA, Ali S, Gholizadeh H, Abas WA
    Sensors (Basel), 2014;14(9):16754-65.
    PMID: 25207872 DOI: 10.3390/s140916754
    The suspension system and socket fitting of artificial limbs have major roles and vital effects on the comfort, mobility, and satisfaction of amputees. This paper introduces a new pneumatic suspension system that overcomes the drawbacks of current suspension systems in donning and doffing, change in volume during daily activities, and pressure distribution in the socket-stump interface. An air pneumatic suspension system (APSS) for total-contact sockets was designed and developed. Pistoning and pressure distribution in the socket-stump interface were tested for the new APSS. More than 95% of the area between each prosthetic socket and liner was measured using a Tekscan F-Scan pressure measurement which has developed matrix-based pressure sensing systems. The variance in pressure around the stump was 8.76 kPa. APSS exhibits less pressure concentration around the stump, improved pressure distribution, easy donning and doffing, adjustability to remain fitted to the socket during daily activities, and more adaptability to the changes in stump volume. The volume changes were adjusted by utility of air pressure sensor. The vertical displacement point and reliability of suspension were assessed using a photographic method. The optimum pressure in every level of loading weight was 55 kPa, and the maximum displacement was 6 mm when 90 N of weight was loaded.
  9. Fulltext Postural stability characteristics of transtibial amputees wearing different prosthetic foot types when standing on various support surfaces
    Arifin N, Abu Osman NA, Ali S, Gholizadeh H, Abas WA
    ScientificWorldJournal, 2014;2014:856279.
    PMID: 25003155 DOI: 10.1155/2014/856279
    This study aimed to evaluate the effects of prosthetic foot types on the postural stability among transtibial amputees when standing on different support surfaces.
  10. Fulltext Review of the socket design and interface pressure measurement for transtibial prosthesis
    Pirouzi G, Abu Osman NA, Eshraghi A, Ali S, Gholizadeh H, Wan Abas WA
    ScientificWorldJournal, 2014;2014:849073.
    PMID: 25197716 DOI: 10.1155/2014/849073
    Socket is an important part of every prosthetic limb as an interface between the residual limb and prosthetic components. Biomechanics of socket-residual limb interface, especially the pressure and force distribution, have effect on patient satisfaction and function. This paper aimed to review and evaluate studies conducted in the last decades on the design of socket, in-socket interface pressure measurement, and socket biomechanics. Literature was searched to find related keywords with transtibial amputation, socket-residual limb interface, socket measurement, socket design, modeling, computational modeling, and suspension system. In accordance with the selection criteria, 19 articles were selected for further analysis. It was revealed that pressure and stress have been studied in the last decaeds, but quantitative evaluations remain inapplicable in clinical settings. This study also illustrates prevailing systems, which may facilitate improvements in socket design for improved quality of life for individuals ambulating with transtibial prosthesis. It is hoped that the review will better facilitate the understanding and determine the clinical relevance of quantitative evaluations.
  11. Interface stress in socket/residual limb with transtibial prosthetic suspension systems during locomotion on slopes and stairs
    Eshraghi A, Abu Osman NA, Gholizadeh H, Ali S, Abas WA
    Am J Phys Med Rehabil, 2015 Jan;94(1):1-10.
    PMID: 24919079 DOI: 10.1097/PHM.0000000000000134
    This study aimed to compare the effects of different suspension methods on the interface stress inside the prosthetic sockets of transtibial amputees when negotiating ramps and stairs.
  12. Fulltext Balance and risk of fall in individuals with bilateral mild and moderate knee osteoarthritis
    Khalaj N, Abu Osman NA, Mokhtar AH, Mehdikhani M, Wan Abas WA
    PLoS One, 2014;9(3):e92270.
    PMID: 24642715 DOI: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC39584
    Balance is essential for mobility and performing activities of daily living. People with knee osteoarthritis display impairment in knee joint proprioception. Thus, the aim of this study was to evaluate balance and risk of fall in individuals with bilateral mild and moderate knee osteoarthritis. Sixty subjects aged between 50 and 70 years volunteered in this study. They were categorized into three groups which were healthy (n = 20), mild (n = 20) and moderate (n = 20) bilateral knee osteoarthritis groups. Dynamic and static balance and risk of fall were assessed using Biodex Stability System. In addition, Timed Up and Go test was used as a clinical test for balance. Results of this study illustrated that there were significant differences in balance (dynamic and static) and risk of fall between three groups. In addition, the main (most significant) difference was found to be between healthy group and moderate group. Furthermore, on clinical scoring of balance, the "Timed Up and Go" test, all three groups showed significant difference. In conclusion, bilateral knee osteoarthritis impaired the balance and increased the risk of fall, particularly in people with moderate knee osteoarthritis.
  13. Effect of geometrical parameters on the performance of longitudinal functionally graded femoral prostheses
    Oshkour AA, Talebi H, Seyed Shirazi SF, Yau YH, Tarlochan F, Abu Osman NA
    Artif Organs, 2015 Feb;39(2):156-64.
    PMID: 24841371 DOI: 10.1111/aor.12315
    This study aimed to assess the performance of different longitudinal functionally graded femoral prostheses. This study was also designed to develop an appropriate prosthetic geometric design for longitudinal functionally graded materials. Three-dimensional models of the femur and prostheses were developed and analyzed. The elastic modulus of these prostheses in the sagittal plane was adjusted along a gradient direction from the distal end to the proximal end. Furthermore, these prostheses were composed of titanium alloy and hydroxyapatite. Results revealed that strain energy, interface stress, and developed stress in the femoral prosthesis and the bone were influenced by prosthetic geometry and gradient index. In all of the prostheses with different geometries, strain energy increased as gradient index increased. Interface stress and developed stress decreased. The minimum principal stress and the maximum principal stress of the bone slightly increased as gradient index increased. Hence, the combination of the femoral prosthetic geometry and functionally graded materials can be employed to decrease stress shielding. Such a combination can also be utilized to achieve equilibrium in terms of the stress applied on the implanted femur constituents; thus, the lifespan of total hip replacement can be prolonged.
  14. Fulltext Gait biomechanics of individuals with transtibial amputation: effect of suspension system
    Eshraghi A, Abu Osman NA, Karimi M, Gholizadeh H, Soodmand E, Wan Abas WA
    PLoS One, 2014;9(5):e96988.
    PMID: 24865351 DOI: 10.1371/journal.pone.0096988
    Prosthetic suspension system is an important component of lower limb prostheses. Suspension efficiency can be best evaluated during one of the vital activities of daily living, i.e. walking. A new magnetic prosthetic suspension system has been developed, but its effects on gait biomechanics have not been studied. This study aimed to explore the effect of suspension type on kinetic and kinematic gait parameters during level walking with the new suspension system as well as two other commonly used systems (the Seal-In and pin/lock). Thirteen persons with transtibial amputation participated in this study. A Vicon motion system (six cameras, two force platforms) was utilized to obtain gait kinetic and kinematic variables, as well as pistoning within the prosthetic socket. The gait deviation index was also calculated based on the kinematic data. The findings indicated significant difference in the pistoning values among the three suspension systems. The Seal-In system resulted in the least pistoning compared with the other two systems. Several kinetic and kinematic variables were also affected by the suspension type. The ground reaction force data showed that lower load was applied to the limb joints with the magnetic suspension system compared with the pin/lock suspension. The gait deviation index showed significant deviation from the normal with all the systems, but the systems did not differ significantly. Main significant effects of the suspension type were seen in the GRF (vertical and fore-aft), knee and ankle angles. The new magnetic suspension system showed comparable effects in the remaining kinetic and kinematic gait parameters to the other studied systems. This study may have implications on the selection of suspension systems for transtibial prostheses. Trial registration: Iranian Registry of Clinical Trials IRCT2013061813706N1.
  15. New method for the isolation of endothelial cells from large vessels
    Ataollahi F, Pingguan-Murphy B, Moradi A, Wan Abas WA, Chua KH, Abu Osman NA
    Cytotherapy, 2014 Aug;16(8):1145-52.
    PMID: 24831838 DOI: 10.1016/j.jcyt.2014.01.010
    Numerous protocols for the isolation of bovine aortic endothelial cells have been described in the previous literature. However, these protocols prevent researchers from obtaining the pure population of endothelial cells. Thus, this study aimed to develop a new and economical method for the isolation of pure endothelial cells by introducing a new strategy to the enzymatic digestion method proposed by previous researchers.
  16. Endothelial cell responses in terms of adhesion, proliferation, and morphology to stiffness of polydimethylsiloxane elastomer substrates
    Ataollahi F, Pramanik S, Moradi A, Dalilottojari A, Pingguan-Murphy B, Wan Abas WA, et al.
    J Biomed Mater Res A, 2015 Jul;103(7):2203-13.
    PMID: 24733741 DOI: 10.1002/jbm.a.35186
    Extracellular environments can regulate cell behavior because cells can actively sense their mechanical environments. This study evaluated the adhesion, proliferation and morphology of endothelial cells on polydimethylsiloxane (PDMS)/alumina (Al2 O3 ) composites and pure PDMS. The substrates were prepared from pure PDMS and its composites with 2.5, 5, 7.5, and 10 wt % Al2 O3 at a curing temperature of 50°C for 4 h. The substrates were then characterized by mechanical, structural, and morphological analyses. The cell adhesion, proliferation, and morphology of cultured bovine aortic endothelial (BAEC) cells on substrate materials were evaluated by using resazurin assay and 1,1'-dioctadecyl-1,3,3,3',3'-tetramethylindocarbocyanine perchlorate-acetylated LDL (Dil-Ac-LDL) cell staining, respectively. The composites (PDMS/2.5, 5, 7.5, and 10 wt % Al2 O3 ) exhibited higher stiffness than the pure PDMS substrate. The results also revealed that stiffer substrates promoted endothelial cell adhesion and proliferation and also induced spread morphology in the endothelial cells compared with lesser stiff substrates. Statistical analysis showed that the effect of time on cell proliferation depended on stiffness. Therefore, this study concludes that the addition of different Al2 O3 percentages to PDMS elevated substrate stiffness which in turn increased endothelial cell adhesion and proliferation significantly and induced spindle shape morphology in endothelial cells.
  17. Mechanical and physical properties of calcium silicate/alumina composite for biomedical engineering applications
    Shirazi FS, Mehrali M, Oshkour AA, Metselaar HS, Kadri NA, Abu Osman NA
    J Mech Behav Biomed Mater, 2014 Feb;30:168-75.
    PMID: 24316872 DOI: 10.1016/j.jmbbm.2013.10.024
    The focus of this study is to investigate the effect of Al2O3 on α-calcium silicate (α-CaSiO3) ceramic. α-CaSiO3 was synthesized from CaO and SiO2 using mechanochemical method followed by calcinations at 1000°C. α-CaSiO3 and alumina were grinded using ball mill to create mixtures, containing 0-50w% of Al2O3 loadings. The powders were uniaxially pressed and followed by cold isostatic pressing (CIP) in order to achieve greater uniformity of compaction and to increase the shape capability. Afterward, the compaction was sintered in a resistive element furnace at both 1150°C and 1250°C with a 5h holding time. It was found that alumina reacted with α-CaSiO3 and formed alumina-rich calcium aluminates after sintering. An addition of 15wt% of Al2O3 powder at 1250°C were found to improve the hardness and fracture toughness of the calcium silicate. It was also observed that the average grain sizes of α-CaSiO3 /Al2O3 composite were maintained 500-700nm after sintering process.
  18. Effect of exercise and gait retraining on knee adduction moment in people with knee osteoarthritis
    Khalaj N, Abu Osman NA, Mokhtar AH, Mehdikhani M, Wan Abas WA
    Proc Inst Mech Eng H, 2014 Feb;228(2):190-9.
    PMID: 24458100 DOI: 10.1177/0954411914521155
    The knee adduction moment represents the medial knee joint load, and greater value is associated with higher load. In people with knee osteoarthritis, it is important to apply proper treatment with the least side effects to reduce knee adduction moment and, consequently, reduce medial knee joint load. This reduction may slow the progression of knee osteoarthritis. The research team performed a literature search of electronic databases. The search keywords were as follows: knee osteoarthritis, knee adduction moment, exercise program, exercise therapy, gait retraining, gait modification and knee joint loading. In total, 12 studies were selected, according to the selection criteria. Findings from previous studies illustrated that exercise and gait retraining programs could alter knee adduction moment in people with knee osteoarthritis. These treatments are noninvasive and nonpharmacological which so far have no or few side effects, as well as being low cost. The results of this review revealed that gait retraining programs were helpful in reducing the knee adduction moment. In contrast, not all the exercise programs were beneficial in reducing knee adduction moment. Future studies are needed to indicate best clinical exercise and gait retraining programs, which are most effective in reducing knee adduction moment in people with knee osteoarthritis.
    Study design: systematic review
  19. Fulltext Evaluation of new suspension system for limb prosthetics
    Gholizadeh H, Abu Osman NA, Eshraghi A, Ali S, Arifin N, Wan Abas WA
    Biomed Eng Online, 2014;13:1.
    PMID: 24410918 DOI: 10.1186/1475-925X-13-1
    Good prosthetic suspension system secures the residual limb inside the prosthetic socket and enables easy donning and doffing. This study aimed to introduce, evaluate and compare a newly designed prosthetic suspension system (HOLO) with the current suspension systems (suction, pin/lock and magnetic systems).
  20. Fulltext Influence of age on patellar tendon reflex response
    Chandrasekhar A, Abu Osman NA, Tham LK, Lim KS, Wan Abas WA
    PLoS One, 2013;8(11):e80799.
    PMID: 24260483 DOI: 10.1371/journal.pone.0080799
    BACKGROUND: A clinical parameter commonly used to assess the neurological status of an individual is the tendon reflex response. However, the clinical method of evaluation often leads to subjective conclusions that may differ between examiners. Moreover, attempts to quantify the reflex response, especially in older age groups, have produced inconsistent results. This study aims to examine the influence of age on the magnitude of the patellar tendon reflex response.

    METHODOLOGY/PRINCIPAL FINDINGS: This study was conducted using the motion analysis technique with the reflex responses measured in terms of knee angles. Forty healthy subjects were selected and categorized into three different age groups. Patellar reflexes were elicited from both the left and right patellar tendons of each subject at three different tapping angles and using the Jendrassik maneuver. The findings suggested that age has a significant effect on the magnitude of the reflex response. An angle of 45° may be the ideal tapping angle at which the reflex can be elicited to detect age-related differences in reflex response. The reflex responses were also not influenced by gender and were observed to be fairly symmetrical.

    CONCLUSIONS/SIGNIFICANCE: Neurologically normal individuals will experience an age-dependent decline in patellar reflex response.

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