Displaying publications 81 - 100 of 116 in total

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  1. Fulltext Physical fitness and motor ability parameters as predictors for skateboarding performance: A logistic regression modelling analysis
    Ab Rasid AM, Muazu Musa R, Abdul Majeed APP, Musawi Maliki ABH, Abdullah MR, Mohd Razmaan MA, et al.
    PLoS One, 2024;19(2):e0296467.
    PMID: 38329954 DOI: 10.1371/journal.pone.0296467
    The identification and prediction of athletic talent are pivotal in the development of successful sporting careers. Traditional subjective assessment methods have proven unreliable due to their inherent subjectivity, prompting the rise of data-driven techniques favoured for their objectivity. This evolution in statistical analysis facilitates the extraction of pertinent athlete information, enabling the recognition of their potential for excellence in their respective sporting careers. In the current study, we applied a logistic regression-based machine learning pipeline (LR) to identify potential skateboarding athletes from a combination of fitness and motor skills performance variables. Forty-five skateboarders recruited from a variety of skateboarding parks were evaluated on various skateboarding tricks while their fitness and motor skills abilities that consist of stork stance test, dynamic balance, sit ups, plank test, standing broad jump, as well as vertical jump, were evaluated. The performances of the skateboarders were clustered and the LR model was developed to classify the classes of the skateboarders. The cluster analysis identified two groups of skateboarders: high and low potential skateboarders. The LR model achieved 90% of mean accuracy specifying excellent prediction of the skateboarder classes. Further sensitivity analysis revealed that static and dynamic balance, lower body strength, and endurance were the most important factors that contributed to the model's performance. These factors are therefore essential for successful performance in skateboarding. The application of machine learning in talent prediction can greatly assist coaches and other relevant stakeholders in making informed decisions regarding athlete performance.
  2. Fulltext Piezoelectric bimorphs' characteristics as in-socket sensors for transfemoral amputees
    El-Sayed AM, Hamzaid NA, Abu Osman NA
    Sensors (Basel), 2014;14(12):23724-41.
    PMID: 25513823 DOI: 10.3390/s141223724
    Alternative sensory systems for the development of prosthetic knees are being increasingly highlighted nowadays, due to the rapid advancements in the field of lower limb prosthetics. This study presents the use of piezoelectric bimorphs as in-socket sensors for transfemoral amputees. An Instron machine was used in the calibration procedure and the corresponding output data were further analyzed to determine the static and dynamic characteristics of the piezoelectric bimorph. The piezoelectric bimorph showed appropriate static operating range, repeatability, hysteresis, and frequency response for application in lower prosthesis, with a force range of 0-100 N. To further validate this finding, an experiment was conducted with a single transfemoral amputee subject to measure the stump/socket pressure using the piezoelectric bimorph embedded inside the socket. The results showed that a maximum interface pressure of about 27 kPa occurred at the anterior proximal site compared to the anterior distal and posterior sites, consistent with values published in other studies. This paper highlighted the capacity of piezoelectric bimorphs to perform as in-socket sensors for transfemoral amputees. However, further experiments are recommended to be conducted with different amputees with different socket types.
  3. 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.
  4. 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.
  5. Fulltext Preliminary analysis of knee stress in full extension landing
    Makinejad MD, Abu Osman NA, Abu Bakar Wan Abas W, Bayat M
    Clinics (Sao Paulo), 2013 Sep;68(9):1180-8.
    PMID: 24141832 DOI: 10.6061/clinics/2013(09)02
    This study provides an experimental and finite element analysis of knee-joint structure during extended-knee landing based on the extracted impact force, and it numerically identifies the contact pressure, stress distribution and possibility of bone-to-bone contact when a subject lands from a safe height.
  6. Progress of key strategies in development of electrospun scaffolds: bone tissue
    Pramanik S, Pingguan-Murphy B, Abu Osman NA
    Sci Technol Adv Mater, 2012 Aug;13(4):043002.
    PMID: 27877500
    There has been unprecedented development in tissue engineering (TE) over the last few years owing to its potential applications, particularly in bone reconstruction or regeneration. In this article, we illustrate several advantages and disadvantages of different approaches to the design of electrospun TE scaffolds. We also review the major benefits of electrospun fibers for three-dimensional scaffolds in hard connective TE applications and identify the key strategies that can improve the mechanical properties of scaffolds for bone TE applications. A few interesting results of recent investigations have been explained for future trends in TE scaffold research.
  7. Prosthesis donning and doffing questionnaire: Development and validation
    Abu Osman NA, Eshraghi A, Gholizadeh H, Wan Abas WAB, Lechler K
    Prosthet Orthot Int, 2017 Dec;41(6):571-578.
    PMID: 28190376 DOI: 10.1177/0309364617690397
    OBJECTIVES: To develop a questionnaire that specifically evaluates the ability of trans-tibial amputees to don and doff a prosthesis and to investigate the psychometric properties of the newly developed questionnaire.

    BACKGROUND: Prosthesis should be donned and doffed few times during the day and night; thus, it is important to measure ease of donning and doffing.

    STUDY DESIGN: A cross-sectional study.

    METHODS: The questionnaire was designed and evaluated by a group of experts. The final questionnaire was administered to 50 individuals with trans-tibial amputation. A test-retest study was also conducted on 20 amputees to assess the repeatability of questionnaire items.

    RESULTS: The prosthesis donning and doffing questionnaire was developed and tested through a pilot study. Based on Kappa index, the questionnaire items showed correlation coefficients greater than 0.7, which indicate good reliability and repeatability. The majority of the participants had good hand dexterity (80%) and could perform all types of grasps. The mean satisfaction scores with donning and doffing were 69.9 and 81.4, respectively. Most of the respondents needed to don and doff the prosthesis 3.44 times per day. Based on a 7-point score, the total scores ranged between 3 and 7.

    CONCLUSION: The prosthesis donning and doffing questionnaire items showed good psychometric properties. A scoring method was suggested based on the pilot sample, which requires further evaluation to be able to differentiate between more suspension types. A larger international multicenter evaluation is required in the future to measure the responsiveness of the scales. This questionnaire will be useful in the evaluation of the ability of amputees to don and doff a trans-tibial limb prosthesis. Clinical relevance Donning and doffing of prostheses are challenging tasks for many lower limb amputees. The prosthesis donning and doffing questionnaire, on its own or combined with other prosthetic evaluation questionnaires, has the potential to help manufacturers, clinicians, and researchers gain knowledge and improve the donning and doffing qualities of prostheses.

  8. Qualitative study of prosthetic suspension systems on transtibial amputees' satisfaction and perceived problems with their prosthetic devices
    Ali S, Abu Osman NA, Naqshbandi MM, Eshraghi A, Kamyab M, Gholizadeh H
    Arch Phys Med Rehabil, 2012 Nov;93(11):1919-23.
    PMID: 22579945 DOI: 10.1016/j.apmr.2012.04.024
    To investigate the effects of 3 dissimilar suspension systems on participants' satisfaction and perceived problems with their prostheses.
  9. Quantitative and qualitative comparison of a new prosthetic suspension system with two existing suspension systems for lower limb amputees
    Eshraghi A, Abu Osman NA, Karimi MT, Gholizadeh H, Ali S, Wan Abas WA
    Am J Phys Med Rehabil, 2012 Dec;91(12):1028-38.
    PMID: 23168378 DOI: 10.1097/PHM.0b013e318269d82a
    The objectives of this study were to compare the effects of a newly designed magnetic suspension system with that of two existing suspension methods on pistoning inside the prosthetic socket and to compare satisfaction and perceived problems among transtibial amputees.
  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. Review on CFD simulation in heart with dilated cardiomyopathy and myocardial infarction
    Chan BT, Lim E, Chee KH, Abu Osman NA
    Comput Biol Med, 2013 May;43(4):377-85.
    PMID: 23428371 DOI: 10.1016/j.compbiomed.2013.01.013
    The heart is a sophisticated functional organ that plays a crucial role in the blood circulatory system. Hemodynamics within the heart chamber can be indicative of exert cardiac health. Due to the limitations of current cardiac imaging modalities, computational fluid dynamics (CFD) have been widely used for the purposes of cardiac function assessment and heart disease diagnosis, as they provide detailed insights into the cardiac flow field. An understanding of ventricular hemodynamics and pathological severities can be gained through studies that employ the CFD method. In this research the hemodynamics of two common myocardial diseases, dilated cardiomyopathy (DCM) and myocardial infarction (MI) were investigated, during both the filling phase and the whole cardiac cycle, through a prescribed geometry and fluid structure interaction (FSI) approach. The results of the research indicated that early stage disease identification and the improvement of cardiac assisting devices and therapeutic procedures can be facilitated through the use of the CFD method.
  12. Satisfaction and problems experienced with transfemoral suspension systems: a comparison between common suction socket and seal-in liner
    Gholizadeh H, Abu Osman NA, Eshraghi A, Ali S, Yahyavi ES
    Arch Phys Med Rehabil, 2013 Aug;94(8):1584-9.
    PMID: 23262380 DOI: 10.1016/j.apmr.2012.12.007
    To compare a seal-in liner with the common suction socket with regards to patient satisfaction and problems experienced with the prosthesis.
  13. Satisfaction and problems experienced with wrist movements: comparison between a common body-powered prosthesis and a new biomechatronics prosthesis
    Abd Razak NA, Abu Osman NA, Kamyab M, Wan Abas WA, Gholizadeh H
    Am J Phys Med Rehabil, 2014 May;93(5):437-44.
    PMID: 24429510 DOI: 10.1097/PHM.0b013e3182a51fc2
    This report compares wrist supination and pronation and flexion and extension movements with the common body-powered prosthesis and a new biomechatronics prosthesis with regard to patient satisfaction and problems experienced with the prosthesis. Fifteen subjects with traumatic transradial amputation who used both prosthetic systems participated in this study. Each subject completed two questionnaires to evaluate their satisfaction and problems experienced with the two prosthetic systems. Satisfaction and problems with the prosthetic's wrist movements were analyzed in terms of the following: supination and pronation; flexion and extension; appearance; sweating; wounds; pain; irritation; pistoning; smell; sound; durability; and the abilities to open a door, hold a cup, and pick up or place objects. This study revealed that the respondents were more satisfied with the biomechatronics wrist prosthesis with regard to supination and pronation, flexion and extension, pain, and the ability to open a door. However, satisfaction with the prosthesis showed no significant differences in terms of sweating, wounds, irritation, pistoning, smell, sound, and durability. The abilities to hold a cup and pick up or place an object were significantly better with the body-powered prosthesis. The results of the survey suggest that satisfaction and problems with wrist movements in persons with transradial amputation can be improved with a biomechatronics wrist prosthesis compared with the common body-powered prosthesis.
  14. Fulltext Sensitivity analysis of left ventricle with dilated cardiomyopathy in fluid structure simulation
    Chan BT, Abu Osman NA, Lim E, Chee KH, Abdul Aziz YF, Abed AA, et al.
    PLoS One, 2013;8(6):e67097.
    PMID: 23825628 DOI: 10.1371/journal.pone.0067097
    Dilated cardiomyopathy (DCM) is the most common myocardial disease. It not only leads to systolic dysfunction but also diastolic deficiency. We sought to investigate the effect of idiopathic and ischemic DCM on the intraventricular fluid dynamics and myocardial wall mechanics using a 2D axisymmetrical fluid structure interaction model. In addition, we also studied the individual effect of parameters related to DCM, i.e. peak E-wave velocity, end systolic volume, wall compliance and sphericity index on several important fluid dynamics and myocardial wall mechanics variables during ventricular filling. Intraventricular fluid dynamics and myocardial wall deformation are significantly impaired under DCM conditions, being demonstrated by low vortex intensity, low flow propagation velocity, low intraventricular pressure difference (IVPD) and strain rates, and high-end diastolic pressure and wall stress. Our sensitivity analysis results showed that flow propagation velocity substantially decreases with an increase in wall stiffness, and is relatively independent of preload at low-peak E-wave velocity. Early IVPD is mainly affected by the rate of change of the early filling velocity and end systolic volume which changes the ventriculo:annular ratio. Regional strain rate, on the other hand, is significantly correlated with regional stiffness, and therefore forms a useful indicator for myocardial regional ischemia. The sensitivity analysis results enhance our understanding of the mechanisms leading to clinically observable changes in patients with DCM.
  15. Simulation of left ventricle flow dynamics with dilated cardiomyopathy during the filling phase
    Chan BT, Ong CW, Lim E, Abu Osman NA, Al Abed A, Lovell NH, et al.
    Annu Int Conf IEEE Eng Med Biol Soc, 2012;2012:6289-92.
    PMID: 23367367 DOI: 10.1109/EMBC.2012.6347432
    Dilated cardiomyopathy (DCM) is a common cardiac disease which leads to the deterioration in cardiac performance. A computational fluid dynamics (CFD) approach can be used to enhance our understanding of the disease, by providing us with a detailed map of the intraventricular flow and pressure distributions. In the present work, effect of ventricular size on the intraventricular flow dynamics and intraventricular pressure gradients (IVPGs) was studied using two different implementation methods, i.e. the geometry-prescribed and the fluid structure interaction (FSI) methods. Results showed that vortex strength and IVPGs are significantly reduced in a dilated heart, leading to an increased risk of thrombus formation and impaired ventricular filling. We suggest FSI method as the ultimate method in studying ventricular dysfunction as it provides additional cardiac disease prognostic factors and more realistic model implementation.
  16. Fulltext Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing
    Asadi-Eydivand M, Solati-Hashjin M, Shafiei SS, Mohammadi S, Hafezi M, Abu Osman NA
    PLoS One, 2016;11(3):e0151216.
    PMID: 26999789 DOI: 10.1371/journal.pone.0151216
    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C-1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C-1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds were observed in this study, the mechanical properties were not significantly improved, requiring further investigations. However, the findings of this study give a better insight into the complex nature of the problem in the fabrication of synthetic bone grafts and scaffolds via post-fabrication treatment of 3DP calcium sulfate prototypes.
  17. Fulltext Surveillance of Injury Types, Locations, and Intensities in Male and Female Tennis Players: A Content Analysis of Online Newspaper Reports
    Musa RM, Hassan I, Abdullah MR, Azmi MNL, P P Abdul Majeed A, Abu Osman NA
    Int J Environ Res Public Health, 2021 12 01;18(23).
    PMID: 34886410 DOI: 10.3390/ijerph182312686
    The popularity of modern tennis has contributed to the increasing number of participants at both recreational and competitive levels. The influx of numerous tennis participants has resulted in a wave of injury occurrences of different types and magnitudes across both male and female players. Since tennis injury harms both players' economic and career development, a better understanding of its epidemiology could potentially curtail its prevalence and occurrences. We used online-based tennis-related injury reports to study the prevalence, location types, and injury intensities in both male and female tennis players for the past five years. It is demonstrated from the chi-square analysis that injury occurrences are significantly associated with a specific gender (χ2(18) = 50.773; p = 0.001), with male players having a higher risk of injury manifestation (68.10%) as compared with female players (31.90%). Nonetheless, knee, hip, ankle, and shoulder injuries are highly prevalent in both male and female players. Moreover, the injury intensities are distributed across gender (χ2(2) = 0.398; p = 0.820), with major injuries being dominant, followed by minor injuries, whilst a few cases of career-threatening injuries were also reported. It was similarly observed that male players recorded a higher degree of both major, minor, and career-threatening injuries than female players. In addition, male players sustained more elbow, hip, knee, shoulder, and thigh injuries than female players. Whereas, female players mostly suffered from Achilles and back injuries, ankle and hamstring injuries affected both genders. The usage of online newspaper reports is pivotal in characterizing the epidemiology of tennis-related injuries based on locations and gender to better understand the pattern and localization of injuries, which could be used to address the problem of modern tennis-related injuries.
  18. Fulltext Synthesis and Characterizations of Novel Ca-Mg-Ti-Fe-Oxides Based Ceramic Nanocrystals and Flexible Film of Polydimethylsiloxane Composite with Improved Mechanical and Dielectric Properties for Sensors
    Tripathy A, Pramanik S, Manna A, Shah NF, Shasmin HN, Radzi Z, et al.
    Sensors (Basel), 2016;16(3):292.
    PMID: 26927116 DOI: 10.3390/s16030292
    Armalcolite, a rare ceramic mineral and normally found in the lunar earth, was synthesized by solid-state step-sintering. The in situ phase-changed novel ceramic nanocrystals of Ca-Mg-Ti-Fe based oxide (CMTFOx), their chemical reactions and bonding with polydimethylsiloxane (PDMS) were determined by X-ray diffraction, infrared spectroscopy, and microscopy. Water absorption of all the CMTFOx was high. The lower dielectric loss tangent value (0.155 at 1 MHz) was obtained for the ceramic sintered at 1050 °C (S1050) and it became lowest for the S1050/PDMS nanocomposite (0.002 at 1 MHz) film, which was made by spin coating at 3000 rpm. The excellent flexibility (static modulus ≈ 0.27 MPa and elongation > 90%), viscoelastic property (tanδ = E″/E': 0.225) and glass transition temperature (Tg: -58.5 °C) were obtained for S1050/PDMS film. Parallel-plate capacitive and flexible resistive humidity sensors have been developed successfully. The best sensing performance of the present S1050 (3000%) and its flexible S1050/PDMS composite film (306%) based humidity sensors was found to be at 100 Hz, better than conventional materials.
  19. Fulltext Techniques for Interface Stress Measurements within Prosthetic Sockets of Transtibial Amputees: A Review of the Past 50 Years of Research
    Al-Fakih EA, Abu Osman NA, Mahmad Adikan FR
    Sensors (Basel), 2016 Jul 20;16(7).
    PMID: 27447646 DOI: 10.3390/s16071119
    The distribution of interface stresses between the residual limb and prosthetic socket of a transtibial amputee has been considered as a direct indicator of the socket quality fit and comfort. Therefore, researchers have been very interested in quantifying these interface stresses in order to evaluate the extent of any potential damage caused by the socket to the residual limb tissues. During the past 50 years a variety of measurement techniques have been employed in an effort to identify sites of excessive stresses which may lead to skin breakdown, compare stress distributions in various socket designs, and evaluate interface cushioning and suspension systems, among others. The outcomes of such measurement techniques have contributed to improving the design and fitting of transtibial sockets. This article aims to review the operating principles, advantages, and disadvantages of conventional and emerging techniques used for interface stress measurements inside transtibial sockets. It also reviews and discusses the evolution of different socket concepts and interface stress investigations conducted in the past five decades, providing valuable insights into the latest trends in socket designs and the crucial considerations for effective stress measurement tools that lead to a functional prosthetic socket.
  20. Fulltext Technology efficacy in active prosthetic knees for transfemoral amputees: a quantitative evaluation
    El-Sayed AM, Hamzaid NA, Abu Osman NA
    ScientificWorldJournal, 2014;2014:297431.
    PMID: 25110727 DOI: 10.1155/2014/297431
    Several studies have presented technological ensembles of active knee systems for transfemoral prosthesis. Other studies have examined the amputees' gait performance while wearing a specific active prosthesis. This paper combined both insights, that is, a technical examination of the components used, with an evaluation of how these improved the gait of respective users. This study aims to offer a quantitative understanding of the potential enhancement derived from strategic integration of core elements in developing an effective device. The study systematically discussed the current technology in active transfemoral prosthesis with respect to its functional walking performance amongst above-knee amputee users, to evaluate the system's efficacy in producing close-to-normal user performance. The performances of its actuator, sensory system, and control technique that are incorporated in each reported system were evaluated separately and numerical comparisons were conducted based on the percentage of amputees' gait deviation from normal gait profile points. The results identified particular components that contributed closest to normal gait parameters. However, the conclusion is limitedly extendable due to the small number of studies. Thus, more clinical validation of the active prosthetic knee technology is needed to better understand the extent of contribution of each component to the most functional development.
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