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Fulltext Optimization and blends study of heterogeneous acid catalyst-assisted esterification of palm oil industry by-product for biodiesel production

Akinfalabi SI, Rashid U, Arbi Nehdi I, Yaw Choong TS, Sbihi HM, Gewik MM

R Soc Open Sci, 2020 Jan;7(1):191592.
PMID: 32218977 DOI: 10.1098/rsos.191592

The optimum conditions to produce palm fatty acid distillate (PFAD)-derived-methyl esters via esterification have been demonstrated with the aid of the response surface methodology (RSM) with central composite rotatable design in the presence of heterogeneous acid catalyst. The effect of four reaction variables, reaction time (30-110 min), reaction temperature (30-70°C), catalyst concentration (1-3 wt.%) and methanol : PFAD molar ratio (3 : 1-11 : 1), were investigated. The reaction time had the most influence on the yield response, while the interaction between the reaction time and the catalyst concentration, with an F-value of 95.61, contributed the most to the esterification reaction. The model had an R2-value of 0.9855, suggesting a fit model, which gave a maximum yield of 95%. The fuel properties of produced PFAD methyl ester were appraised based on the acid value, iodine value, cloud and pour points, flash point, kinematic viscosity, density, ash and water contents and were compared with biodiesel EN 14214 and ASTM D-6751 standard limits. The PFAD methyl ester was further blended with petro-diesel from B0, B3, B5, B10, B20 and B100, on a volumetric basis. The blends were characterized by TGA, DTG and FTIR. With an acid value of 0.42 (mg KOH g-1), iodine value of 63 (g.I2/100 g), kinematic viscosity of 4.31 (mm2 s-1), the PFAD methyl ester has shown good fuel potential, as all of its fuel properties were within the permissible international standards for biodiesel.

Matched MeSH terms: Biomechanical Phenomena
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.

Matched MeSH terms: Biomechanical Phenomena
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.

Matched MeSH terms: Biomechanical Phenomena
Fulltext Lunge as a sport-specific exercise: a mini review

Ali Md Nadzalan, Muhammad Hannan Sazali, Mohamad Shahrul Azzfar

Journal of Engineering and Science Research, 2018;2(1):6-10.
MyJurnal

As a way to enhance performance in sports, apart from in-field or in court training, athletes are recommended to adopt resistance training into their training routine. As an exercise that needs the performer to split their legs, lunge is suggested to be included as an exercise in a training session. Various researches had been conducted on lunge and several findings showed different methods or protocols of lunge affect the kinematics, kinetics muscle activation and fascicle behaviour response during the exercise. Although not much study conducted on the chronic adaptations, the existing studies suggested that performers should well plan the training protocols as this will cause different training adaptations.

Matched MeSH terms: Biomechanical Phenomena
Finite element study of functionally graded porous femoral stems incorporating body-centered cubic structure

Alkhatib SE, Tarlochan F, Mehboob H, Singh R, Kadirgama K, Harun WSBW

Artif Organs, 2019 Jul;43(7):E152-E164.
PMID: 30805945 DOI: 10.1111/aor.13444

The mismatch between stiffness of the femoral dense stem and host bone causes complications to patients, such as aseptic loosening and bone resorption. Three-dimensional finite-element models of homogeneous porous (HGP) and functionally graded porous (FGP) stems incorporating body-centered cubic (BCC) structures are proposed in this article as an alternative to the dense stems. The relationship between the porosity and strut thickness of the BCC structure was developed to construct the finite-element models. Three levels of porosities (20%, 50%, and 80%) were modeled in HGP and FGP stems. The porosity of the stems was decreased distally according to the sigmoid function (n = 0.1, n = 1 and n = 10) with 3 grading exponents. The results showed that FGP stems transferred 120%-170% higher stresses to the femur (Gruen zone 7) as compared to the solid stem. Conversely, the stresses in HGP and FGP stems were 12%-34% lower than the dense stem. The highest micromotions (105-147 µm) were observed for stems of 80% overall porosity, and the lowest (42-46 µm) was for stems of 20% overall porosity. Finally, FGP stems with a grading exponent of n = 10 resulted in an 11%-28% reduction in micromotions.

Matched MeSH terms: Biomechanical Phenomena
Fulltext Comparison of lower limb kinematics during early and late phases of 2km time trial on stationary rowing ergometer among male national rowers

Amirah Zahiran, Fara Liana Zainuddin, Shazlin Shaharudin

Malaysian Journal of Medicine and Health Sciences, 2020;16(3):3-7.
MyJurnal

Introduction: In this study, we evaluated the kinematics of lower limb during early and late phases of 2km time trial on stationary rowing ergometer among Malaysian male rowers. Methods: Seventeen national-level rowers voluntari- ly participated. Three dimensional lower limb kinematics data were collected to represent the first 400 m (i.e., early) and the last 400m (i.e., late) phases of 2km time trial on a stationary ergometer. The kinematics data at sagittal, frontal and transverse planes of dominant leg during catch and finish positions were compared across early and late phases of the time trial using paired T-test. Results: The kinematics of lower limb joints at three planes were not significantly different during early versus late phases of 2km time trial among male senior rowers except for hip flexion at finish (p=0.411), ankle rotation at catch (p=0.779) and ankle abduction at finish (p=0.677). Conclusion: Lower limb kine- matics particularly the hip flexion, ankle rotation and ankle abduction may change across early and late phases of 2km time trial due to fatigue. Coaches and rowers should monitor these motions during fatiguing rowing piece and develop necessary injury prevention measures.

Matched MeSH terms: Biomechanical Phenomena
Biomechanical responses of thigh and lower leg during 10 consecutive soccer instep kicks

Amiri-Khorasani M, Abu Osman NA, Yusof A

J Strength Cond Res, 2011 Apr;25(4):1177-81.
PMID: 20838249 DOI: 10.1519/JSC.0b013e3181d6508c

This study investigated the number of trials necessary to obtain optimal biomechanical responses in 10 consecutive soccer instep kicks. The kicking motions of dominant legs were captured from 5 experienced and skilled adult male soccer players (height: 184.60 ± 4.49 cm; mass: 80 ± 4.24 kg; and age: 25.60 ± 1.14 years) using a 3D infrared high-speed camera at 200 Hz. Some of the important kinematics and kinetics parameters are maximum thigh angular velocity, maximum lower leg angular velocity, maximum of thigh moment, maximum lower leg moment at forward and impact phases, and finally maximum ball velocity after impact selected to be analyzed. There was a significant decrease of ball velocity between the first and the fifth kick and the subsequent kicks. Similarly, the lower leg angular velocity showed a significant decrease after the fifth kick and thereafter. Compared with the first kick, the thigh angular velocity has been shown to decrease after the sixth kick and thereafter, and the thigh moment result of the sixth kick was significantly lower when compared with the first kick. Moreover, the lower leg moment result of the fourth kick was significantly lower in comparison with the first kick. In conclusion, it seems that 5 consecutive kicks are adequate to achieve high kinematics and kinetics responses and selecting more than 5 kicks does not result in any high biomechanical responses for analysis.

Matched MeSH terms: Biomechanical Phenomena/physiology
Fulltext Dynamic finite element analysis of mobile bearing type knee prosthesis under deep flexional motion

Anuar MA, Todo M, Nagamine R, Hirokawa S

ScientificWorldJournal, 2014;2014:586921.
PMID: 25133247 DOI: 10.1155/2014/586921

The primary objective of this study is to distinguish between mobile bearing and fixed bearing posterior stabilized knee prostheses in the mechanics performance using the finite element simulation. Quantifying the relative mechanics attributes and survivorship between the mobile bearing and the fixed bearing prosthesis remains in investigation among researchers. In the present study, 3-dimensional computational model of a clinically used mobile bearing PS type knee prosthesis was utilized to develop a finite element and dynamic simulation model. Combination of displacement and force driven knee motion was adapted to simulate a flexion motion from 0° to 135° with neutral, 10°, and 20° internal tibial rotation to represent deep knee bending. Introduction of the secondary moving articulation in the mobile bearing knee prosthesis has been found to maintain relatively low shear stress during deep knee motion with tibial rotation.

Matched MeSH terms: Biomechanical Phenomena
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.

Matched MeSH terms: Biomechanical Phenomena
Hybrid learning control for improving suppression of hand tremor

As'arry A, Md Zain MZ, Mailah M, Hussein M

Proc Inst Mech Eng H, 2013 Nov;227(11):1171-80.
PMID: 23901066 DOI: 10.1177/0954411913494325

Patients with hand tremors may find routine activities such as writing and holding objects affected. In response to this problem, an active control technique has been examined in order to lessen the severity of tremors. In this article, an online method of a hybrid proportional-integral control with active force control strategy for tremor attenuation is presented. An intelligent mechanism using iterative learning control is incorporated into the active force control loop to approximate the estimation mass parameter. Experiments were conducted on a dummy hand model placed horizontally in a tremor test rig. When activated by a shaker in the vertical direction, this resembles a postural tremor condition. In the proportional-integral plus active force control, a linear voice coil actuator is used as the main active tremor suppressive element. A sensitivity analysis is presented to investigate the robustness of the proposed controller in a real-time control environment. The findings of this study demonstrate that the intelligent active force control and iterative learning controller show excellent performance in reducing tremor error compared to classic pure proportional, proportional-integral and hybrid proportional-integral plus active force control controllers.

Matched MeSH terms: Biomechanical Phenomena
The use of sonication treatment to decellularize aortic tissues for preparation of bioscaffolds

Azhim A, Syazwani N, Morimoto Y, Furukawa KS, Ushida T

J Biomater Appl, 2014 Jul;29(1):130-41.
PMID: 24384523 DOI: 10.1177/0885328213517579

A novel decellularization method using sonication treatment is described. Sonication treatment is the combination of physical and chemical agents. These methods will disrupt cell membrane and release cell contents to external environments. The cell removal was facilitated by subsequent rinsing of sodium dodecyl sulfate detergents. Sonication treatment is used in the preparation of complete decellularized bioscaffolds. The aim of this study is to confirm the usefulness of sonication treatment for preparation of biological scaffolds. In this study, samples of aortic tissues are decellularized by sonication treatment at frequency of 170 kHz in 0.1% and 2% sodium dodecyl sulfate detergents for 10-h treatment time. The relation between decellularization and sonication parameters such as dissolved oxygen concentration, conductivity, and pH is investigated. Histological analysis and biomechanical testing is performed to evaluate cell removal efficiency as well as changes in biomechanical properties. Minimal inflammation response elicit by bioscaffolds is confirmed by xenogeneic implantation and immunohistochemistry. Sonication treatment is able to produce complete decellularized tissue suggesting that these treatments could be applied widely as one of the decellularization method.

Matched MeSH terms: Biomechanical Phenomena
Fulltext Molecular Mechanisms of Stress-Responsive Changes in Collagen and Elastin Networks in Skin

Aziz J, Shezali H, Radzi Z, Yahya NA, Abu Kassim NH, Czernuszka J, et al.

Skin Pharmacol Physiol, 2016;29(4):190-203.
PMID: 27434176 DOI: 10.1159/000447017

Collagen and elastin networks make up the majority of the extracellular matrix in many organs, such as the skin. The mechanisms which are involved in the maintenance of homeostatic equilibrium of these networks are numerous, involving the regulation of genetic expression, growth factor secretion, signalling pathways, secondary messaging systems, and ion channel activity. However, many factors are capable of disrupting these pathways, which leads to an imbalance of homeostatic equilibrium. Ultimately, this leads to changes in the physical nature of skin, both functionally and cosmetically. Although various factors have been identified, including carcinogenesis, ultraviolet exposure, and mechanical stretching of skin, it was discovered that many of them affect similar components of regulatory pathways, such as fibroblasts, lysyl oxidase, and fibronectin. Additionally, it was discovered that the various regulatory pathways intersect with each other at various stages instead of working independently of each other. This review paper proposes a model which elucidates how these molecular pathways intersect with one another, and how various internal and external factors can disrupt these pathways, ultimately leading to a disruption in collagen and elastin networks.

Matched MeSH terms: Biomechanical Phenomena/physiology
AFM analysis of collagen fibrils in expanded scalp tissue after anisotropic tissue expansion

Aziz J, Ahmad MF, Rahman MT, Yahya NA, Czernuszka J, Radzi Z

Int J Biol Macromol, 2018 Feb;107(Pt A):1030-1038.
PMID: 28939521 DOI: 10.1016/j.ijbiomac.2017.09.066

Successful use of tissue expanders depends on the quality of expanded tissue. This study evaluates the impact of anisotropic self-inflating tissue expander (SITE) on the biomechanics of skin. Two different SITE were implanted subcutaneously on sheep scalps; SITE that requires 30days for maximum expansion (Group A; n=5), and SITE that requires 21days for maximum expansion (Group B; n=5). Control animals (n=5) were maintained without SITE implantation. Young's Modulus, D-periodicity, overlap and gap region length, diameter, and height difference between overlap and gap regions on collagen fibrils were analyzed using atomic force microscopy. Histology showed no significant differences in dermal thickness between control and expanded skin of groups A and B. Furthermore, most parameters of expanded skin were similar to controls (p>0.05). However, the height difference between overlap and gap regions was significantly smaller in group B compared to both control and group A (p<0.01). Strong correlation was observed between Young's Modulus of overlap and gap regions of the control and group A, but not group B. Results suggest that a relatively slower SITE can be useful in reconstructive surgery to maintain the biomechanical properties of expanded skin.

Matched MeSH terms: Biomechanical Phenomena
Fulltext The Effects of Leg Length Discrepancy on Stability and Kinematics-Kinetics Deviations: A Systematic Review

Azizan NA, Basaruddin KS, Salleh AF

Appl Bionics Biomech, 2018;2018:5156348.
PMID: 30116295 DOI: 10.1155/2018/5156348

Various studies have examined body posture stability, including postural sway and associated biomechanical parameters, to assess the severity effects of leg length discrepancy (LLD). However, various viewpoints have been articulated on the results of these studies because of certain drawbacks in the comprehensive analysis of the effect of variations in LLD magnitude. Therefore, this systematic review was performed to help focus on the current findings to help identify which biomechanical parameters are most relevant, commonly used, and able to distinguish and/or have specific clinical relevance to the effect of variations in LLD magnitude during static (standing) and dynamic (walking) conditions. Several electronic databases containing studies from the year 1983 to 2016 (Scopus, ScienceDirect, PubMed, PMC, and ProQuest) were obtained in our literature search. The search process yielded 22 published articles that fulfilled our criteria. We found most of the published data that we analyzed to be inconsistent, and very little data was obtained on the correlation between LLD severity and changes in body posture stability during standing and walking. However, the results of the present review study are in line with previous observational studies, which describe asymmetry in the lower limbs corresponding to biomechanical parameters such as gait kinematics, kinetics, and other parameters described during static (standing) postural balance. In future investigations, we believe that it might be useful to use and exploit other balance-related factors that may potentially influence body posture stability.

Matched MeSH terms: Biomechanical Phenomena
Fulltext Leg Length Discrepancy: Dynamic Balance Response during Gait

Azizan NA, Basaruddin KS, Salleh AF, Sulaiman AR, Safar MJA, Rusli WMR

J Healthc Eng, 2018;2018:7815451.
PMID: 29983905 DOI: 10.1155/2018/7815451

Balance in the human body's movement is generally associated with different synergistic pathologies. The trunk is supported by one's leg most of the time when walking. A person with poor balance may face limitation when performing their physical activities on a daily basis, and they may be more prone to having risk of fall. The ground reaction forces (GRFs), centre of pressure (COP), and centre of mass (COM) in quite standing posture were often measured for the evaluation of balance. Currently, there is still no experimental evidence or study on leg length discrepancy (LLD) during walking. Analysis of the stability parameters is more representative of the functional activity undergone by the person who has a LLD. Therefore, this study hopes to shed new light on the effects of LLD on the dynamic stability associated with VGRF, COP, and COM during walking. Eighteen healthy subjects were selected among the university population with normal BMIs. Each subject was asked to walk with 1.0 to 2.0 ms-1 of walking speed for three to five trials each. Insoles of 0.5 cm thickness were added, and the thickness of the insoles was subsequently raised until 4 cm and placed under the right foot as we simulated LLD. The captured data obtained from a force plate and motion analysis present Peak VGRF (single-leg stance) and WD (double-leg stance) that showed more forces exerted on the short leg rather than long leg. Obviously, changes occurred on the displacement of COM trajectories in the ML and vertical directions as LLD increased at the whole gait cycle. Displacement of COP trajectories demonstrated that more distribution was on the short leg rather than on the long leg. The root mean square (RMS) of COP-COM distance showed, obviously, changes only in ML direction with the value at 3 cm and 3.5 cm. The cutoff value via receiver operating characteristic (ROC) indicates the significant differences starting at the level 2.5 cm up to 4 cm in long and short legs for both AP and ML directions. The present study performed included all the proposed parameters on the effect of dynamic stability on LLD during walking and thus helps to determine and evaluate the balance pattern.

Matched MeSH terms: Biomechanical Phenomena
Fulltext The HUKM Spinal Instrumentation System for adolescent idiopathic scoliosis. A biomechanical comparison study using finite element analysis

Azlan AM, Mohammad AR, Ariffin AK

Med J Malaysia, 2005 Jul;60 Suppl C:30-4.
PMID: 16381280 MyJurnal

This finite element analysis is aimed at comparing relative stiffness of three different posterior instrumentation constructs: the Hospital Universiti Kebangsaan Malaysia Spinal Instrumentation System (HUKM-SIS), the Cotrell-Dubousset Instrumentation (CDI) and Harrington Instrumentation System (HIS), used in the treatment of adolescent idiopathic scoliosis (AIS). The constructs were tested under various loads using MSC Patran 2001 r2a. Under increasing flexion loads, there was a linearly corresponding increase in deflection magnitudes for all constructs on the load-deflection curve. The CDI was the stiffest construct under axial, forward flexion and extension loads, followed by the HUKM-SIS and HIS. Under lateral bending loads, the HUKM-SIS construct was the stiffest followed by CDI and HIS. The HUKM-SIS construct was stiffer than HIS under torsional loads. We conclude that multiple pedicle screws increase the stiffness of posterior instrumentation constructs under all loads and inter-segmental spinous processes wiring increase the stiffness against lateral bending.

Matched MeSH terms: Biomechanical Phenomena
Biomechanical analysis of the wrist arthroplasty in rheumatoid arthritis: a finite element analysis

Bajuri MN, Abdul Kadir MR, Murali MR, Kamarul T

Med Biol Eng Comput, 2013 Feb;51(1-2):175-86.
PMID: 23124814 DOI: 10.1007/s11517-012-0982-9

The total replacement of wrists affected by rheumatoid arthritis (RA) has had mixed outcomes in terms of failure rates. This study was therefore conducted to analyse the biomechanics of wrist arthroplasty using recently reported implants that have shown encouraging results with the aim of providing some insights for the future development of wrist implants. A model of a healthy wrist was developed using computed tomography images from a healthy volunteer. An RA model was simulated based on all ten general characteristics of the disease. The ReMotion ™ total wrist system was then modelled to simulate total wrist arthroplasty (TWA). Finite element analysis was performed with loads simulating the static hand grip action. The results show that the RA model produced distorted patterns of stress distribution with tenfold higher contact pressure than the healthy model. For the TWA model, contact pressure was found to be approximately fivefold lower than the RA model. Compared to the healthy model, significant improvements were observed for the TWA model with minor variations in the stress distribution. In conclusion, the modelled TWA reduced contact pressure between bones but did not restore the stress distribution to the normal healthy condition.

Matched MeSH terms: Biomechanical Phenomena
Mechanical and functional assessment of the wrist affected by rheumatoid arthritis: A finite element analysis

Bajuri MN, Kadir MR, Raman MM, Kamarul T

Med Eng Phys, 2012 Nov;34(9):1294-302.
PMID: 22277308 DOI: 10.1016/j.medengphy.2011.12.020

Understanding the pathomechanics involved in rheumatoid arthritis (RA) of the wrist provides valuable information, which will invariably allow various therapeutic possibilities to be explored. The computational modelling of this disease permits the appropriate simulation to be conducted seamlessly. A study that underpins the fundamental concept that produces the biomechanical changes in a rheumatoid wrist was thus conducted through the use of finite element method. The RA model was constructed from computed tomography datasets, taking into account three major characteristics: synovial proliferation, cartilage destruction and ligamentous laxity. As control, a healthy wrist joint model was developed in parallel and compared. Cartilage was modelled based on the shape of the articulation while the ligaments were modelled with linear spring elements. A load-controlled analysis was performed simulating physiological hand grip loading conditions. The results demonstrated that the diseased model produced abnormal wrist extension and stress distribution as compared to the healthy wrist model. Due to the weakening of the ligaments, destruction of the cartilage and lower bone density, the altered biomechanical stresses were particularly evident at the radioscaphoid and capitolunate articulations which correlate to clinical findings. These results demonstrate the robust finding of the developed RA wrist model, which accurately predicted the pathological process.

Matched MeSH terms: Biomechanical Phenomena
Racial variations in knee joint laxity: A comparative study of the Jordanian Arab and Malay populations

Bashaireh KM, Yabroudi MA, Nawasreh ZH, Al-Zyoud SM, Bashir NB, Aleshawi AJ, et al.

Knee, 2020 Aug;27(4):1205-1211.
PMID: 32711883 DOI: 10.1016/j.knee.2020.05.003

BACKGROUND: A high incidence of joint laxity has been reported among Asians compared with Western populations, but clear differences between more specific ethnic populations have not been established. This study aimed to determine the average knee laxity in the Malaysian and Jordanian populations.
METHODS: Jordanian and Malaysian medical students from our institution were invited to participate in the study. General demographic data and factors affecting joint laxity were obtained from each participant using a printed questionnaire. Both knees were examined using the anterior drawer test while in 90° of flexion. Knee laxity was measured by three separate independent investigators through a knee laxity tester.
RESULTS: One hundred and eighty-six participants (95 females) were enrolled in the study. Among them, 108 Malaysians participated. The Jordanians had significantly higher knee laxity in both knees compared with the Malaysians. The mean average right knee laxity for Jordanians was 2.98 mm vs. 2.72 mm for Malaysians (P = 0.005). Similarly, the mean average left knee laxity for Jordanians was 2.95 mm, while for Malaysians, it was 2.62 mm (P = 0.0001). Furthermore, smokers had significantly more laxity in both knees. After performing a multivariate linear regression analysis for all factors, race was the only independent factor that affected knee laxity in both knees.
CONCLUSIONS: Race is directly associated with knee laxity. Jordanians tend to have more laxity in knee joints compared with Malaysians. Larger multi-center and genetic studies are recommended to establish the racial differences between different ethnic groups.

Matched MeSH terms: Biomechanical Phenomena
A novel motion sensor-driven control system for FES-assisted walking after spinal cord injury: A pilot study

Braz GP, Russold MF, Fornusek C, Hamzaid NA, Smith RM, Davis GM

Med Eng Phys, 2016 11;38(11):1223-1231.
PMID: 27346492 DOI: 10.1016/j.medengphy.2016.06.007

This pilot study reports the development of a novel closed-loop (CL) FES-gait control system, which employed a finite-state controller that processed kinematic feedback from four miniaturized motion sensors. This strategy automated the control of knee extension via quadriceps and gluteus stimulation during the stance phase of gait on the supporting leg, and managed the stimulation delivered to the common peroneal nerve (CPN) during swing-phase on the contra-lateral limb. The control system was assessed against a traditional open-loop (OL) system on two sensorimotor 'complete' paraplegic subjects. A biomechanical analysis revealed that the closed-loop control of leg swing was efficient, but without major advantages compared to OL. CL automated the control of knee extension during the stance phase of gait and for this reason was the method of preference by the subjects. For the first time, a feedback control system with a simplified configuration of four miniaturized sensors allowed the addition of instruments to collect the data of multiple physiological and biomechanical variables during FES-evoked gait. In this pilot study of two sensorimotor complete paraplegic individuals, CL ameliorated certain drawbacks of current OL systems - it required less user intervention and accounted for the inter-subject differences in their stimulation requirements.

Matched MeSH terms: Biomechanical Phenomena

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