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Are the spatio-temporal parameters of gait capable of distinguishing a faller from a non-faller elderly?

Mortaza N, Abu Osman NA, Mehdikhani N

Eur J Phys Rehabil Med, 2014 Dec;50(6):677-91.
PMID: 24831570

Fall is a common and a major cause of injuries. It is important to find elderlies who are prone to falls. The majority of serious falls occur during walking among the older adults. Analyzing the spatio-temporal parameters of walking is an easy way of assessment in the clinical setting, but is it capable of distinguishing a faller from a non-faller elderly? Through a systematic review of the literature, the objective of this systematic review was to identify and summarize the differences in the spatio-temporal parameters of walking in elderly fallers and non-fallers and to find out if these parameters are capable of distinguishing a faller from a non-faller. All original research articles which compared any special or temporal walking parameters in faller and non-faller elderlies were systematically searched within the Scopus and Embase databases. Effect size analysis was also done to standardize findings and compare the gait parameters of fallers and non-fallers across the selected studies. The electronic search led to 5381 articles. After title and abstract screening 30 articles were chosen; further assessment of the full texts led to 17 eligible articles for inclusion in the review. It seems that temporal measurements are more sensitive to the detection of risk of fall in elderly people. The results of the 17 selected studies showed that fallers have a tendency toward a slower walking speed and cadence, longer stride time, and double support duration. Also, fallers showed shorter stride and step length, wider step width and more variability in spatio-temporal parameters of gait. According to the effect size analysis, step length, gait speed, stride length and stance time variability were respectively more capable of differentiating faller from non-faller elderlies. However, because of the difference of methodology and number of studies which investigated each parameter, these results are prone to imprecision. Spatio-temporal analysis of level walking is not sufficient and cannot act as a reliable predictor of falls in elderly individuals.
WITHDRAWN: Patient-specific interface pressure case study at transradial prosthetic socket: comparison trials between ICRC polypropylene socket and air splint socket

Abd Razak NA, Abu Osman NA, Ali SA, Gholizadeh H

Eur J Phys Rehabil Med, 2016 Jan 15.
PMID: 26771916

Ahead of Print article withdrawn by publisher
Fulltext On the use of virtual reality for individuals with upper limb loss: a systematic scoping review

Hashim NA, Abd Razak NA, Shanmuganathan T, Jaladin RA, Gholizadeh H, Abu Osman NA

Eur J Phys Rehabil Med, 2022 Aug;58(4):612-620.
PMID: 35044131 DOI: 10.23736/S1973-9087.22.06794-6

INTRODUCTION: Virtual reality has recently become a popular application for rehabilitation and motor control research. This technology has emerged as a valid addition to conventional therapy and promises a successful rehabilitation. This study describes recent research related to the use of virtual reality applications in the rehabilitation of individuals with upper limb loss and to see whether this technology has enough proof of its applicability.
EVIDENCE ACQUISITION: Searches were conducted with the Web of Science, Google Scholar, IEEE Xplore, and PubMed databases from inception up to September 2020. Articles that employed virtual reality in the rehabilitation of individual with upper limb loss were included in the research if it is written in English, the keyword exists in the title and abstract; it uses visual feedback in nonimmersive, semi-immersive, or fully immersive virtual environments. Data extraction was carried out by two independent researchers. The study was drafted using the Preferred Reporting Items for Systematic Reviews and Meta-analysis Protocols (PRISMA).
EVIDENCE SYNTHESIS: A total of 38 articles met the inclusion criteria. Most studies were published between 2010 and 2020. Thirty-nine percent of the studies (N.=15), originates from North America; 55% of the studies (N.=21), were publicly funded; 61% of the studies (N.=24), was without disclosure of conflict of interest; 82% of the studies (N.=31), were cited in other studies. All the studies were published in journals and conference proceedings. Sixty-six percent of the studies (N.=25) has come out with positive outcome. The design studies were mostly case reports, case series, and poorly designed cohort studies that made up 55% (N.=21) of all the studies cited here.
CONCLUSIONS: The research conducted on the use of virtual reality in individual with upper limb loss rehabilitation is of very low quality. The improvements to the research protocol are much needed. It is not necessary to develop new devices, but rather to assess existing devices with well-conducted randomized controlled trials.
Fulltext Evaluation of Trigonella foenum-graecum extract in combination with swimming exercise compared to glibenclamide consumption on type 2 Diabetic rodents

Arshadi S, Azarbayjani MA, Hajaghaalipor F, Yusof A, Peeri M, Bakhtiyari S, et al.

Food Nutr Res, 2015;59:29717.
PMID: 26699937 DOI: 10.3402/fnr.v59.29717

The purpose of the present study was to evaluate the effect of fenugreek seed extract in combination with swimming exercise compared to glibenclamide consumption on type 2 diabetic rats.
Fulltext Analysis of Interrelationships among Voluntary and Prosthetic Leg Joint Parameters Using Cyclograms

Jasni F, Hamzaid NA, Mohd Syah NE, Chung TY, Abu Osman NA

Front Neurosci, 2017;11:230.
PMID: 28487630 DOI: 10.3389/fnins.2017.00230

The walking mechanism of a prosthetic leg user is a tightly coordinated movement of several joints and limb segments. The interaction among the voluntary and mechanical joints and segments requires particular biomechanical insight. This study aims to analyze the inter-relationship between amputees' voluntary and mechanical coupled leg joints variables using cyclograms. From this analysis, the critical gait parameters in each gait phase were determined and analyzed if they contribute to a better powered prosthetic knee control design. To develop the cyclogram model, 20 healthy able-bodied subjects and 25 prosthesis and orthosis users (10 transtibial amputees, 5 transfemoral amputees, and 10 different pathological profiles of orthosis users) walked at their comfortable speed in a 3D motion analysis lab setting. The gait parameters (i.e., angle, moment and power for the ankle, knee and hip joints) were coupled to form 36 cyclograms relationship. The model was validated by quantifying the gait disparities of all the pathological walking by analyzing each cyclograms pairs using feed-forward neural network with backpropagation. Subsequently, the cyclogram pairs that contributed to the highest gait disparity of each gait phase were manipulated by replacing it with normal values and re-analyzed. The manipulated cyclograms relationship that showed highest improvement in terms of gait disparity calculation suggested that they are the most dominant parameters in powered-knee control. In case of transfemoral amputee walking, it was identified using this approach that at each gait sub-phase, the knee variables most responsible for closest to normal walking were: knee power during loading response and mid-stance, knee moment and knee angle during terminal stance phase, knee angle and knee power during pre-swing, knee angle at initial swing, and knee power at terminal swing. No variable was dominant during mid-swing phase implying natural pendulum effect of the lower limb between the initial and terminal swing phases. The outcome of this cyclogram adoption approach proposed an insight into the method of determining the causal effect of manipulating a particular joint's mechanical properties toward the joint behavior in an amputee's gait by determining the curve closeness, C, of the modified cyclogram curve to the normal conventional curve, to enable quantitative judgment of the effect of changing a particular parameter in the prosthetic leg gait.
Fulltext A longitudinal analysis of injury characteristics among elite and amateur tennis players at different tournaments from electronic newspaper reports

Musa RM, Hassan I, Abdullah MR, Latiff Azmi MN, Abdul Majeed APP, Abu Osman NA

Front Public Health, 2022;10:835119.
PMID: 36033746 DOI: 10.3389/fpubh.2022.835119

The non-complexity of tennis, coupled with its health benefits, renders it appealing and encourages varying competitions at different levels of age, gender, and expertise. However, the rapid increase in the participation rates witnesses a surge in injury occurrences, prompting the need for in-depth analysis to facilitate immediate intervention. We employed a media content analysis technique in which tennis-associated articles published in the last 5 years were examined. A total of 207 news reports were gathered and screened for analysis. Subsequently, 71 articles were excluded from the study due to content duplications or summary updates of existing news articles, while 23 news articles were also excluded from the study due to inappropriateness. Finally, 113 news reports directly related to injury in tennis were coded and analyzed. We examined various types of injuries reported from the screened articles with respect to their status (fresh, recurrent, and recovery) across expertise levels i.e., elite, or amateur. Similarly, the incidence of injury occurrences based on the types of tournaments the players engage in was also investigated. A chi-square analysis was employed to achieve the objectives of the study. Occurrences of tennis-associated injuries are disseminated across expertise levels [ χ ( 18 ) 2 = 16.542; p = 0.555], with knee, hip, elbow, and shoulder injuries being highly prevalent in both elite and amateur players. Nevertheless, it was noted that elite players suffered a staggering 72.60% of injury-related problems, while amateur players sustained 27.40% of injuries. Moreover, the status of injury spreads based on types of tournaments [ χ ( 4 ) 2 = 3.374; p = 0.497], with higher occurrences of fresh and recurrent injuries, while low recovery rates were observed. The findings further demonstrated that injuries are sustained regardless of tournament types [ χ ( 36 ) 2 = 39.393; p = 0.321]. However, most of the injuries occurred at international tournaments (85%). Whereas, only 5.30% of the injuries occurred at national/regional tournaments while 9.70% were unidentified. It could be deduced from the findings of this investigation that elite players are more prone to injuries compared with amateur players. Furthermore, the most common tennis-related injuries affect the lower, trunk, and upper regions of the body, respectively. A large number of the reported tennis injuries are fresh and recurrent, with a few recoveries. The international tennis tournaments are highly attributed to injury occurrences as opposed to the national/regional tournaments. The application of the media-based data mining technique is non-trivial in projecting injury-related problems that could be used to facilitate the development of an injury index peculiar to the tennis sport for prompt intervention.
Fulltext Balance control in lower extremity amputees during quiet standing: a systematic review

Ku PX, Abu Osman NA, Wan Abas WA

Gait Posture, 2014 Feb;39(2):672-82.
PMID: 24331296 DOI: 10.1016/j.gaitpost.2013.07.006

Postural control has been widely evaluated for the normal population and different groups over the past 20 years. Numerous studies have investigated postural control in quiet standing posture among amputees. However, a comprehensive analysis is lacking on the possible contributing factors to balance. The present systematic review highlights the current findings on variables that contribute to balance instability for lower extremity amputees. The search strategy was performed on PubMed, Web of Science, Medline, Scopus, and CINAHL and then followed by additional manual searching via reference lists in the reviewed articles. The quality of the articles was evaluated using a methodological quality assessment tool. This review included and evaluated a total of 23 full-text articles. Despite the inconsistencies in the methodological design of the studies, all articles scored above the acceptable level in terms of quality. A majority of the studies revealed that lower extremity amputees have increased postural sway in the standing posture. Asymmetry in body weight, which is mainly distributed in the non-amputated leg, was described. Aside from the centre of pressure in postural control, sensory inputs may be a related topic for investigation in view of evidence on their contribution, particularly visual input. Other balance-related factors, such as stump length and patients' confidence level, were also neglected. Further research requires examination on the potential factors that affect postural control as the information of standing postural is still limited.
Combined effects of knee brace, laterally wedged insoles and toe-in gait on knee adduction moment and balance in moderate medial knee osteoarthritis patients

Khan SJ, Khan SS, Usman J, Mokhtar AH, Abu Osman NA

Gait Posture, 2018 03;61:243-249.
PMID: 29413792 DOI: 10.1016/j.gaitpost.2018.01.024

OBJECTIVE: To test the hypothesis that toe-in gait (TI) will further reduce first peak (Knee Adduction Moment) KAM and decrease balance when combined with a knee brace (KB) and laterally wedged insoles (LWI) in medial knee osteoarthritis (kOA) patients.
PARTICIPANTS: Twenty patients with bilateral symptomatic medial kOA.
INTERVENTIONS: 4-point leverage-based KB, full-length LWI with 5° inclination and toe-in gait (TI).
MAIN OUTCOME MEASURES: First and second peak knee adduction moment (fKAM and sKAM respectively), balance and pain.
METHODS: The fKAM and sKAM were determined from 3-dimensional gait analysis with six randomized conditions: (1) N (without any intervention), (2) KB, (3) KB + TI, (4) LWI, (5) LWI + TI, (6) KB + LWI + TI. Balance was assessed by Biodex Balance System using three stability settings, (i) Static (ii) Moderate dynamic setting for fall risk (FR12) and (iii) High dynamic setting for fall risk (FR8).
RESULTS: The reduction in fKAM and sKAM was greatest (19.75% and 12%) when TI was combined with KB and LWI respectively. No change in balance was observed when TI combined with KB, and LWI and when used concurrently with both the orthosis at static and FR12 conditions. Significant balance reduction was found at FR8 for KB + TI (22.22%), and KB + LWI + TI (35.71%). Pain increased significantly for KB (258%), KB + TI (305%), LWI + TI (210%) and KB + LWI + TI (316%). LWI showed no effect on pain.
CONCLUSIONS: There is a synergistic effect of TI when combined with KB and LWI concurrently in sKAM reduction. However, the concurrent use of TI, KB and LWI decreases balance and pain as assessed on a highly dynamic platform.
Study site: Department of Sports Medicine, University of Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
Finite element analysis on longitudinal and radial functionally graded femoral prosthesis

Oshkour AA, Abu Osman NA, Davoodi MM, Yau YH, Tarlochan F, Wan Abas WA, et al.

Int J Numer Method Biomed Eng, 2013 Dec;29(12):1412-27.
PMID: 23922316 DOI: 10.1002/cnm.2583

This study focused on developing a 3D finite element model of functionally graded femoral prostheses to decrease stress shielding and to improve total hip replacement performance. The mechanical properties of the modeled functionally graded femoral prostheses were adjusted in the sagittal and transverse planes by changing the volume fraction gradient exponent. Prostheses with material changes in the sagittal and transverse planes were considered longitudinal and radial prostheses, respectively. The effects of cemented and noncemented implantation methods were also considered in this study. Strain energy and von Mises stresses were determined at the femoral proximal metaphysis and interfaces of the implanted femur components, respectively. Results demonstrated that the strain energy increased proportionally with increasing volume fraction gradient exponent, whereas the interface stresses decreased on the prostheses surfaces. A limited increase was also observed at the surfaces of the bone and cement. The periprosthetic femur with a noncemented prosthesis exhibited higher strain energy than with a cemented prosthesis. Radial prostheses implantation displayed more strain energy than longitudinal prostheses implantation in the femoral proximal part. Functionally graded materials also increased strain energy and exhibited promising potentials as substitutes of conventional materials to decrease stress shielding and to enhance total hip replacement lifespan.
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.
Enhanced performance with elastic resistance during the eccentric phase of a countermovement jump

Aboodarda SJ, Yusof A, Abu Osman NA, Thompson MW, Mokhtar AH

Int J Sports Physiol Perform, 2013 Mar;8(2):181-7.
PMID: 23428490

To identify the effect of additional elastic force on the kinetic and kinematic characteristics, as well as the magnitude of leg stiffness, during the performance of accentuated countermovement jumps (CMJs).
Factors Associated With How Long People Would Like to Live

Awang H, Nik Osman NA, Mansor N, Ab Rashid NF, Lih Yoong T

Int Q Community Health Educ, 2020 Jul;40(4):345-352.
PMID: 31876255 DOI: 10.1177/0272684X19896733

This article examined the factors of how long people would like to live involving 462 respondents aged 40 years and older in Malaysia. Data collected through an online self-administered survey indicated that 75% of the respondents would like to live at least 80 years and on average most people would like to live 81 years. Rural respondents, those who agreed that they have a loving family, those who agreed that they want to continue working for as long as they can, respondents who believed that they will not need long-term care at 65 years and older, and those who may consider living in an assisted living facility were more likely to want to live at least 80 years compared with respondents who did not agree. Efforts should be targeted at promoting healthy lifestyle and providing more employment opportunities for older persons.
Fulltext Video Game-Based Rehabilitation Approach for Individuals Who Have Undergone Upper Limb Amputation: Case-Control Study

Hashim NA, Abd Razak NA, Gholizadeh H, Abu Osman NA

JMIR Serious Games, 2021 Feb 04;9(1):e17017.
PMID: 33538698 DOI: 10.2196/17017

BACKGROUND: Brain plasticity is an important factor in prosthesis usage. This plasticity helps with brain adaptation to learn new movement and coordination patterns needed to control a prosthetic hand. It can be achieved through repetitive muscle training that is usually very exhausting and often results in considerable reduction in patient motivation. Previous studies have shown that a playful concept in rehabilitation can increase patient engagement and perseverance.
OBJECTIVE: This study investigated whether the inclusion of video games in the upper limb amputee rehabilitation protocol could have a beneficial impact for muscle preparation, coordination, and patient motivation among individuals who have undergone transradial upper limb amputation.
METHODS: Ten participants, including five amputee participants and five able-bodied participants, were enrolled in 10 1-hour sessions within a 4-week rehabilitation program. In order to investigate the effects of the rehabilitation protocol used in this study, virtual reality box and block tests and electromyography (EMG) assessments were performed. Maximum voluntary contraction was measured before, immediately after, and 2 days after interacting with four different EMG-controlled video games. Participant motivation was assessed with the Intrinsic Motivation Inventory (IMI) questionnaire and user evaluation survey.
RESULTS: Survey analysis showed that muscle strength and coordination increased at the end of training for all the participants. The results of Pearson correlation analysis indicated that there was a significant positive association between the training period and the box and block test score (r8=0.95, P
Intrarater test-retest reliability of static and dynamic stability indexes measurement using the Biodex Stability System during unilateral stance

Arifin N, Abu Osman NA, Wan Abas WA

J Appl Biomech, 2014 Apr;30(2):300-4.
PMID: 23878204 DOI: 10.1123/jab.2013-0130

The measurements of postural balance often involve measurement error, which affects the analysis and interpretation of the outcomes. In most of the existing clinical rehabilitation research, the ability to produce reliable measures is a prerequisite for an accurate assessment of an intervention after a period of time. Although clinical balance assessment has been performed in previous study, none has determined the intrarater test-retest reliability of static and dynamic stability indexes during dominant single stance. In this study, one rater examined 20 healthy university students (female=12, male=8) in two sessions separated by 7 day intervals. Three stability indexes--the overall stability index (OSI), anterior/posterior stability index (APSI), and medial/ lateral stability index (MLSI) in static and dynamic conditions--were measured during single dominant stance. Intraclass correlation coefficient (ICC), standard error measurement (SEM) and 95% confidence interval (95% CI) were calculated. Test-retest ICCs for OSI, APSI, and MLSI were 0.85, 0.78, and 0.84 during static condition and were 0.77, 0.77, and 0.65 during dynamic condition, respectively. We concluded that the postural stability assessment using Biodex stability system demonstrates good-to-excellent test-retest reliability over a 1 week time interval.
Extracellular matrix integrity affects the mechanical behaviour of in-situ chondrocytes under compression

Moo EK, Han SK, Federico S, Sibole SC, Jinha A, Abu Osman NA, et al.

J Biomech, 2014 Mar 21;47(5):1004-13.
PMID: 24480705 DOI: 10.1016/j.jbiomech.2014.01.003

Cartilage lesions change the microenvironment of cells and may accelerate cartilage degradation through catabolic responses from chondrocytes. In this study, we investigated the effects of structural integrity of the extracellular matrix (ECM) on chondrocytes by comparing the mechanics of cells surrounded by an intact ECM with cells close to a cartilage lesion using experimental and numerical methods. Experimentally, 15% nominal compression was applied to bovine cartilage tissues using a light-transmissible compression system. Target cells in the intact ECM and near lesions were imaged by dual-photon microscopy. Changes in cell morphology (N(cell)=32 for both ECM conditions) were quantified. A two-scale (tissue level and cell level) Finite Element (FE) model was also developed. A 15% nominal compression was applied to a non-linear, biphasic tissue model with the corresponding cell level models studied at different radial locations from the centre of the sample in the transient phase and at steady state. We studied the Green-Lagrange strains in the tissue and cells. Experimental and theoretical results indicated that cells near lesions deform less axially than chondrocytes in the intact ECM at steady state. However, cells near lesions experienced large tensile strains in the principal height direction, which are likely associated with non-uniform tissue radial bulging. Previous experiments showed that tensile strains of high magnitude cause an up-regulation of digestive enzyme gene expressions. Therefore, we propose that cartilage degradation near tissue lesions may be due to the large tensile strains in the principal height direction applied to cells, thus leading to an up-regulation of catabolic factors.
Dual photon excitation microscopy and image threshold segmentation in live cell imaging during compression testing

Moo EK, Abusara Z, Abu Osman NA, Pingguan-Murphy B, Herzog W

J Biomech, 2013 Aug 9;46(12):2024-31.
PMID: 23849134 DOI: 10.1016/j.jbiomech.2013.06.007

Morphological studies of live connective tissue cells are imperative to helping understand cellular responses to mechanical stimuli. However, photobleaching is a constant problem to accurate and reliable live cell fluorescent imaging, and various image thresholding methods have been adopted to account for photobleaching effects. Previous studies showed that dual photon excitation (DPE) techniques are superior over conventional one photon excitation (OPE) confocal techniques in minimizing photobleaching. In this study, we investigated the effects of photobleaching resulting from OPE and DPE on morphology of in situ articular cartilage chondrocytes across repeat laser exposures. Additionally, we compared the effectiveness of three commonly-used image thresholding methods in accounting for photobleaching effects, with and without tissue loading through compression. In general, photobleaching leads to an apparent volume reduction for subsequent image scans. Performing seven consecutive scans of chondrocytes in unloaded cartilage, we found that the apparent cell volume loss caused by DPE microscopy is much smaller than that observed using OPE microscopy. Applying scan-specific image thresholds did not prevent the photobleaching-induced volume loss, and volume reductions were non-uniform over the seven repeat scans. During cartilage loading through compression, cell fluorescence increased and, depending on the thresholding method used, led to different volume changes. Therefore, different conclusions on cell volume changes may be drawn during tissue compression, depending on the image thresholding methods used. In conclusion, our findings confirm that photobleaching directly affects cell morphology measurements, and that DPE causes less photobleaching artifacts than OPE for uncompressed cells. When cells are compressed during tissue loading, a complicated interplay between photobleaching effects and compression-induced fluorescence increase may lead to interpretations in cell responses to mechanical stimuli that depend on the microscopic approach and the thresholding methods used and may result in contradictory interpretations.
Biomechanical evaluation of the relationship between postural control and body mass index

Ku PX, Abu Osman NA, Yusof A, Wan Abas WA

J Biomech, 2012 Jun 1;45(9):1638-42.
PMID: 22507349 DOI: 10.1016/j.jbiomech.2012.03.029

Postural stability is crucial in maintaining body balance during quiet standing, locomotion, and any activities that require a high degree of balance performance, such as participating in sports and dancing. Research has shown that there is a relationship between stability and body mass. The aims of this study were to examine the impact that two variables had on static postural control: body mass index (BMI) and gender. Eighty healthy young adults (age=21.7±1.8 yr; height=1.65±0.09 m; mass=67.5±19.0 kg) participated in the study and the static postural control was assessed using the Biodex Balance System, with a 20 Hz sampling rate in the bipedic stance (BLS) and unipedic stance (ULS) for 30s. Five test evaluations were performed for each balance test. Postural control was found to be negatively correlated with increased adiposity, as the obese BMI group performed significantly poorer than the underweight, normal weight and overweight groups during BLS and ULS tests. The underweight, normal weight and overweight groups exhibited greater anterior-posterior stability in postural control during quiet stance. In addition, female displayed a trend of having a greater postural sway than male young adults, although it was evidenced in only some BMI groups. This study revealed that BMI do have an impact on postural control during both BLS and ULS. As such, BMI and gender-specific effects should be taken into consideration when selecting individuals for different types of sporting activities, especially those that require quiet standing.
The limits of stability and muscle activity in middle-aged adults during static and dynamic stance

Ku PX, Abu Osman NA, Wan Abas WAB

J Biomech, 2016 Dec 08;49(16):3943-3948.
PMID: 27865478 DOI: 10.1016/j.jbiomech.2016.11.006

Balance control plays an important role in maintaining daily activity. However, studies on postural control among middle-aged adults are scarce. This study aims (i) to examine directional control (DCL) and electromyography activity (EMG) for different stability levels, and (ii) to determine left-right asymmetry for DCL and muscle activity among sedentary middle-aged adults. Twenty healthy, middle-aged adults (10 males, 10 females; age=50.0±7.5yrs; body height: 1.61±0.10m; body mass: 70.0±14.5kg) participated in the study. EMG for left and right side of rectus femoris (RF), biceps femoris (BF), and medial gastrocnemius (MG) were recorded. Two-way repeated measures analysis of variance was used to assess the effect of dynamic level on DCL and EMG, whereas independent sample t-test was conducted to analyse the asymmetries of DCL and EMG for the left and right leg. When the dynamic tilt surface increased, DCL scores significantly decreased (except forward, forward-rightward, and backward-leftward direction) and only RF muscle indicated significant differences. Left-right asymmetry was found in BF and MG muscles. No significant gender difference was observed in DCL and EMG. These data demonstrated that increased dynamic tilt surface may increase the displacement of center of pressure of certain directions, and stimulate RF activity in dynamic stance among sedentary middle-aged adults. Further studies should be conducted to examine the dynamic stance and muscle activity of the lower limb in age-matched patient groups with balance abnormalities.
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.
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.

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