Displaying publications 101 - 120 of 251 in total

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  1. Akimov SA, Volynsky PE, Galimzyanov TR, Kuzmin PI, Pavlov KV, Batishchev OV
    Sci Rep, 2017 10 02;7(1):12509.
    PMID: 28970526 DOI: 10.1038/s41598-017-12749-x
    Lipid membranes are extremely stable envelopes allowing cells to survive in various environments and to maintain desired internal composition. Membrane permeation through formation of transversal pores requires substantial external stress. Practically, pores are usually formed by application of lateral tension or transmembrane voltage. Using the same approach as was used for obtaining continuous trajectory of pore formation in the stress-less membrane in the previous article, we now consider the process of pore formation under the external stress. The waiting time to pore formation proved a non-monotonous function of the lateral tension, dropping from infinity at zero tension to a minimum at the tension of several millinewtons per meter. Transmembrane voltage, on the contrary, caused the waiting time to decrease monotonously. Analysis of pore formation trajectories for several lipid species with different spontaneous curvatures and elastic moduli under various external conditions provided instrumental insights into the mechanisms underlying some experimentally observed phenomena.
    Matched MeSH terms: Biomechanical Phenomena
  2. Hisham S, Kadirgama K, Mohammed HA, Kumar A, Ramasamy D, Samykano M, et al.
    Molecules, 2020 Jun 28;25(13).
    PMID: 32605301 DOI: 10.3390/molecules25132975
    Friction and wear are the main factors in the failure of the piston in automobile engines. The objective of this work was to improve the tribological behaviour and lubricant properties using hybrid Cellulose Nanocrystal (CNC) and Copper (II) oxide nanoparticles blended with SAE 40 as a base fluid. The two-step method was used in the hybrid nanofluid preparation. Three different concentrations were prepared in a range of 0.1% to 0.5%. Kinematic viscosity and viscosity index were also identified. The friction and wear behavior were evaluated using a tribometer based on ASTM G181. The CNC-CuO nano lubricant shows a significant improvement in term of viscosity index by 44.3-47.12% while for friction, the coefficient of friction (COF) decreases by 1.5%, respectively, during high and low-speed loads (boundary regime), and 30.95% during a high-speed, and low load (mixed regime). The wear morphologies results also show that a smoother surface was obtained after using CNC-CuO nano lubricant compared to SAE 40.
    Matched MeSH terms: Biomechanical Phenomena
  3. Muhammad Hanif Ramlee
    MyJurnal
    Most orthopaedic cases that involved with bone fracture are normally treated with medical implants. To be noticed that some precautions in terms of biomechanical and biomaterial properties are necessary for a successful post-sur- gery process. The biomechanical evaluation of implants could be carried out using computing and engineering technologies. However, in the computer simulation, some assumptions are needed as the limitations on computer resources and data input. This review focuses on the current method of developing the finite element model for patients with specific values of material properties for lower limb part such as hip, knee and ankle joint. Previous literature was reviewed from which keywords and search engines were identified. In this review, inclusion and exclusion criteria were used to limit the literature search. We reviewed the state-of-the-art in this area and provide recommendations for future research. In conclusion, the previous published reports illustrated different methods to develop numerical models.
    Matched MeSH terms: Biomechanical Phenomena
  4. Wong CF, Yuen KH, Peh KK
    Int J Pharm, 1999 Mar 25;180(1):47-57.
    PMID: 10089291
    A method using a texture analyzer equipment and chicken pouch as the biological tissue was investigated for measuring the bioadhesive properties of polymers under simulated buccal conditions. The method was evaluated using two polymers, namely Carbopol 974P and Methocel K4M while the instrument variables studied included the contact force, contact time and speed of withdrawal of the probe from the tissue. The parameters measured were the work of adhesion and peak detachment force. Longer contact time and faster probe speed not only gave better reproducibility of results, but also better sensitivities for both parameters measured. On the other hand, a certain level of contact force was found essential for achieving good bioadhesion, above which there was no further contribution to the bioadhesion process. When the method was applied to determine the bioadhesiveness of several polymers, the values obtained for the work of adhesion and peak detachment force were quite consistent in the ranking of the polymers. The Carbopols were found to have the highest values, followed by gelatin, sodium carboxymethyl celluloses and hydroxypropylmethyl celluloses. On the other hand, Alginic acid, Eudragit RLPO and RSPO, and Chitosan appeared to have low bioadhesive values.
    Matched MeSH terms: Biomechanical Phenomena
  5. Mousa MA, Abdullah JY, Jamayet NB, Alam MK, Husein A
    Biomed Res Int, 2021;2021:6419774.
    PMID: 34447852 DOI: 10.1155/2021/6419774
    Aim: This systematic review is aimed at investigating the biomechanical stress that develops in the maxillofacial prostheses (MFP) and supporting structures and methods to optimize it. Design and Methods. A literature survey was conducted for full-text English articles which used FEA to examine the stress developed in conventional and implant-assisted MFPs from January 2010 to December 2020.

    Results: 87 articles were screened to get an update on the desired information. 74 were excluded based on a complete screening, and finally, 13 articles were recruited for complete reviewing. Discussion. The MFP is subjected to stress, which is reflected in the form of compressive and tensile strengths. The stress is mainly concentrated the resection line and around the apices of roots of teeth next to the defect. Diversity of designs and techniques were introduced to optimize the stress distribution, such as modification of the clasp design, using materials with different mechanical properties for dentures base and retainer, use of dental (DI) and/or zygomatic implants (ZI), and free flap reconstruction before prosthetic rehabilitation.

    Conclusion: Using ZI in the defective side of the dentulous maxillary defect and defective and nondefective side of the edentulous maxillary defect was found more advantageous, in terms of compression and tensile stress and retention, when compared with DI and free flap reconstruction.

    Matched MeSH terms: Biomechanical Phenomena
  6. Zainal Abidin NA, Abdul Wahab AH, Abdul Rahim RA, Abdul Kadir MR, Ramlee MH
    Med Biol Eng Comput, 2021 Sep;59(9):1945-1960.
    PMID: 34392448 DOI: 10.1007/s11517-021-02419-6
    Complication rates of anterior cruciate ligament reconstruction (ACL-R) were reported to be around 15% although it is a common arthroscopic procedure with good outcomes. Breakage and migration of fixators are still possible even months after surgery. A fixator with optimum stability can minimise those two complications. Factors that affect the stability of a fixator are its configuration, material, and design. Thus, this paper aims to analyse the biomechanical effects of different types of fixators (cross-pin, interference screw, and cortical button) towards the stability of the knee joint after ACL-R. In this study, finite element modelling and analyses of a knee joint attached with double semitendinosus graft and fixators were carried out. Mimics and 3-Matic softwares were used in the development of the knee joint models. Meanwhile, the graft and fixators were designed by using SolidWorks software. Once the meshes of all models were finished in 3-Matic, simulation of the configurations was done using MSC Marc Mentat software. A 100-N anterior tibial load was applied onto the tibia to simulate the anterior drawer test. Based on the findings, cross-pin was found to have optimum stability in terms of stress and strain at the femoral fixation site for better treatment of ACL-R.
    Matched MeSH terms: Biomechanical Phenomena
  7. Sarpeshkar V, Mann DL, Spratford W, Abernethy B
    Hum Mov Sci, 2017 Aug;54:82-100.
    PMID: 28410536 DOI: 10.1016/j.humov.2017.04.003
    Successful interception relies on the use of perceptual information to accurately guide an efficient movement strategy that allows performers to be placed at the right place at the right time. Although previous studies have highlighted the differences in the timing and coordination of movement that underpin interceptive expertise, very little is known about how these movement patterns are adapted when intercepting targets that follow a curvilinear flight-path. The aim of this study was to examine how curvilinear ball-trajectories influence movement patterns when intercepting a fast-moving target. Movement timing and coordination was examined when four groups of cricket batters, who differed in their skill level and/or age, hit targets that followed straight or curvilinear flight-paths. The results revealed that when compared to hitting straight trials, (i) mixing straight with curvilinear trials altered movement coordination and when the ball was hit, (ii) curvilinear trajectories reduced interceptive performance and significantly delayed the timing of all kinematic moments, but there were (iii) larger decrease in performance when the ball swung away from (rather than in towards) the performer. Movement coordination differed between skill but not age groups, suggesting that skill-appropriate movement patterns that are apparent in adults may have fully emerged by late adolescence.
    Matched MeSH terms: Biomechanical Phenomena
  8. Vanrenterghem, Jos, Zulezwan A. Malik, G. Burniston, Jatin
    MyJurnal
    Journal of Sports Science and Physical Education 5(2): 9-14, 2016 - Jump squat tests can be
    used to investigate the differences in the force - velocity (f-v) profile in movement that is
    more a sport-specific than isolated exercises such as open chain leg extension. However,
    squat jumps involve multi-joint movement, making it questionable which muscle is the main
    contributor for the movement. The main aim of this study is to develop a test of isolated knee
    extension that encompasses the entire range of human f-v relationship and to investigate the
    correlation between linear encoder and kinematic measurement of angular velocity using a
    camera system during unloaded kicking. One healthy male subject volunteered to participate
    in the study and performed 10 unloaded kicks (knee extension). A cuff was strapped around
    the lower leg, approximately 2 cm above the medial malleoli and connected to a linear
    velocity encoder (MuscleLab Ergotest version 4010, Norway). During the test sessions, threedimensional
    motion analysis was performed with an Oqus Motion Capture System (Qualisys,
    Sweden). Data were transferred to Windows-based data acquisition software (Qualisys Track
    Manager). There was a positive linear relationship (r = 0.94). The unloaded kicking test to
    determine maximum angular velocity at knee extension measured using the QTM showed
    that the mean angular velocity was 362˚.s-1, with the highest value being 528˚.s-1. This
    preliminary study suggests isokinetic dynamometry (IKD) can be used to investigate the
    entire range of velocities (i.e isometric – velocity maximum) of knee extension in normal
    human subjects. Further studies can examine the use of IKD in measuring higher velocities.
    Matched MeSH terms: Biomechanical Phenomena
  9. Pearson SJ, Mohammed ASA, Hussain SR
    J Biomech, 2017 08 16;61:45-50.
    PMID: 28736078 DOI: 10.1016/j.jbiomech.2017.06.038
    PURPOSE: Descriptive data on the aspects of site specific in vivo tendon strain with varying knee joint angle are non-existent. The present study determines and compares surface and deep layer strain of the patellar tendon during isometric contractions across a range of knee joint angles.

    METHODS: Male participants (age 22.0±3.4) performed ramped isometric knee extensions at knee joint angles of 90°, 70°, 50° and 30° of flexion. Strain patterns of the anterior and posterior regions of the patellar tendon were determined using real-time B-mode ultrasonography at each knee joint angle. Regional strain measures were compared using an automated pixel tracking method.

    RESULTS: Strain was seen to be greatest for both the anterior and posterior regions with the knee at 90° (7.76±0.89% and 5.06±0.76%). Anterior strain was seen to be significantly greater (p<0.05) than posterior strain for all knee angles apart from 30°, 90°=(7.76vs. 5.06%), 70°=(4.77vs. 3.75%), and 50°=(3.74vs. 2.90%). The relative strain (ratio of anterior to posterior), was greatest with the knee joint angle at 90°, and decreased as the knee joint angle reduced.

    CONCLUSIONS: The results from this study indicate that not only are there greater absolute tendon strains with the knee in greater flexion, but that the knee joint angle affects the regional strain differentially, resulting in greater shear between the tendon layers with force application when the knee is in greater degrees of flexion. These results have important implications for rehabilitation and training.

    Matched MeSH terms: Biomechanical Phenomena
  10. Lussiana T, Gindre C, Mourot L, Hébert-Losier K
    Eur J Sport Sci, 2017 Aug;17(7):847-857.
    PMID: 28488928 DOI: 10.1080/17461391.2017.1325072
    Running patterns are often categorized into subgroups according to common features before data analysis and interpretation. The Volodalen® method is a simple field-based tool used to classify runners into aerial or terrestrial using a 5-item subjective rating scale. We aimed to validate the Volodalen® method by quantifying the relationship between its subjective scores and 3D biomechanical measures. Fifty-four runners ran 30 s on a treadmill at 10, 12, 14, 16, and 18 km h-1 while their kinematics were assessed subjectively using the Volodalen® method and objectively using 3D motion capture. For each runner and speed, two researchers scored the five Volodalen® items on a 1-to-5 scale, which addressed vertical oscillation, upper-body motion, pelvis and foot position at ground contact, and footstrike pattern. Seven 3D biomechanical parameters reflecting the subjective items were also collected and correlated to the subjective scores. Twenty-eight runners were classified as aerial and 26 as terrestrial. Runner classification did not change with speed, but the relative contribution of the biomechanical parameters to the subjective classification was speed dependent. The magnitude of correlations between subjective and objective measures ranged from trivial to very large. Five of the seven objective parameters significantly differed between aerial and terrestrial runners, and these parameters demonstrated the strongest correlations to the subjective scores. Our results support the validity of the Volodalen® method, whereby the visual appreciation of running gait reflected quantifiable objective parameters. Two minor modifications to the method are proposed to simplify its use and improve agreement between subjective and objective measures.
    Matched MeSH terms: Biomechanical Phenomena
  11. Ngoh KJ, Gouwanda D, Gopalai AA, Chong YZ
    J Biomech, 2018 07 25;76:269-273.
    PMID: 29945786 DOI: 10.1016/j.jbiomech.2018.06.006
    Wearable technology has been viewed as one of the plausible alternatives to capture human motion in an unconstrained environment, especially during running. However, existing methods require kinematic and kinetic measurements of human body segments and can be complicated. This paper investigates the use of neural network model (NN) and accelerometer to estimate vertical ground reaction force (VGRF). An experimental study was conducted to collect sufficient samples for training, validation and testing. The estimated results were compared with VGRF measured using an instrumented treadmill. The estimates yielded an average root mean square error of less than 0.017 of the body weight (BW) and a cross-correlation coefficient greater than 0.99. The results also demonstrated that NN could estimate impact force and active force with average errors ranging between 0.10 and 0.18 of BW at different running speeds. Using NN and uniaxial accelerometer can (1) simplify the estimation of VGRF, (2) reduce the computational requirement and (3) reduce the necessity of multiple wearable sensors to obtain relevant parameters.
    Matched MeSH terms: Biomechanical Phenomena
  12. Sia SF, Zhao X, Li R, Zhang Y, Chong W, He L, et al.
    Proc Inst Mech Eng H, 2016 Nov;230(11):1051-1058.
    PMID: 28095764 DOI: 10.1177/0954411916671752
    BACKGROUND: Internal carotid artery stenosis requires an accurate risk assessment for the prevention of stroke. Although the internal carotid artery area stenosis ratio at the common carotid artery bifurcation can be used as one of the diagnostic methods of internal carotid artery stenosis, the accuracy of results would still depend on the measurement techniques. The purpose of this study is to propose a novel method to estimate the effect of internal carotid artery stenosis on the blood flow based on the concept of minimization of energy loss.

    METHODS: Eight internal carotid arteries from different medical centers were diagnosed as stenosed internal carotid arteries, as plaques were found at different locations on the vessel. A computational fluid dynamics solver was developed based on an open-source code (OpenFOAM) to test the flow ratio and energy loss of those stenosed internal carotid arteries. For comparison, a healthy internal carotid artery and an idealized internal carotid artery model have also been tested and compared with stenosed internal carotid artery in terms of flow ratio and energy loss.

    RESULTS: We found that at a given common carotid artery bifurcation, there must be a certain flow distribution in the internal carotid artery and external carotid artery, for which the total energy loss at the bifurcation is at a minimum; for a given common carotid artery flow rate, an irregular shaped plaque at the bifurcation constantly resulted in a large value of minimization of energy loss. Thus, minimization of energy loss can be used as an indicator for the estimation of internal carotid artery stenosis.

    Matched MeSH terms: Biomechanical Phenomena
  13. Nehdi IA, Sbihi HM, Blidi LE, Rashid U, Tan CP, Al-Resayes SI
    Protein Pept Lett, 2018;25(2):164-170.
    PMID: 28240158 DOI: 10.2174/0929866524666170223150839
    BACKGROUND: Biodiesel is a green fuel consisting of long chain fatty acid monoalkyl esters, which can be blended with diesel or used alone which is usually produced from vegetable oils/fats by either lipasecatalyzed transesterification. In this investigation, an enzyme (Novozym 435) catalyzed process was optimized to prepare methyl esters from crude Citrullus colocynthis oil (CCO) by transesterification of CCO with methanol. However, as per our knowledge, lipase-catalyzed transesterification have not been used for biodiesel production from Citrullus colocynthis.

    OBJECTIVE: The purpose of this work was to transesterify the CCO in the presence of Candida antarctica lipase as catalyst and methanol. Additionally, the physicochemical parameters/fuel properties of the Citrullus colocynthis methyl ester (CCME) were assessed and compared.

    METHODS: Lipase-catalyzed reactions were carried out in three necked flask (50 mL) attached with reflux condenser and thermometer, immersed in oil bath at constant stirring speed (400 rpm). The reaction mixture was consisted of CCO and varying the calculated amount of methanol, tert-butyl alcohol, and Novozym 435. The experimental parameters reaction time, methanol/oil molar ratio, reaction temperature, tert-butanol content, Novozym 435 content and water content were optimized for the transesterification reaction. The CCME yield was measured using gas chromatograph. The fuel properties of the produced CCME were determined as per American Society for Testing and Materials (ASTM) and European (EN) biodiesel standard methods.

    RESULTS: In this study, an enzymatic catalyst was employed to synthesize the CCME from CCO via transesterification. Several variables affecting the CCME yield were optimized as lipase quantity (4%), water content (0.5%), methanol/oil molar ratio (5:1), reaction temperature (43 °C), reaction medium composition (80% tertbutanol/ oil), and reaction time (3.7 h). A CCME yield of 97.8% was achieved using enzyme catalyzed transesterification of CCO under optimal conditions. The significant biodiesel fuel properties of CCME, i.e. cloud point (0.70 °C); cetane number (49.07); kinematic viscosity (2.27 mm2/s); flash point (143 °C); sulfur content (2 ppm) density (880 kg/m3) and acid value (0.076 mg KOH/g) were appraised. CCME also exhibited long-term storage stability (4.80 h) and all the biodiesel fuel properties were within the range of standards (ASTM D6751 and EN 14214).

    CONCLUSION: The lipase-catalyzed transesterification produced better conversion than the base-catalyzed reaction. The fuel properties of CCME were within the limits of the ASTM D6751 and EN14214 standards. Furthermore, CCME showed good oxidative stability and a long shelf life due its high natural antioxidant content. CCME showed better fuel properties and long-term storage stability due to which it can be used as a potential alternative fuel.

    Matched MeSH terms: Biomechanical Phenomena
  14. Hasan CZC, Jailani R, Md Tahir N, Ilias S
    Res Dev Disabil, 2017 Jul;66:55-63.
    PMID: 28284567 DOI: 10.1016/j.ridd.2017.02.015
    Minimal information is known about the three-dimensional (3D) ground reaction forces (GRF) on the gait patterns of individuals with autism spectrum disorders (ASD). The purpose of this study was to investigate whether the 3D GRF components differ significantly between children with ASD and the peer controls. 15 children with ASD and 25 typically developing (TD) children had participated in the study. Two force plates were used to measure the 3D GRF data during walking. Time-series parameterization techniques were employed to extract 17 discrete features from the 3D GRF waveforms. By using independent t-test and Mann-Whitney U test, significant differences (p<0.05) between the ASD and TD groups were found for four GRF features. Children with ASD demonstrated higher maximum braking force, lower relative time to maximum braking force, and lower relative time to zero force during mid-stance. Children with ASD were also found to have reduced the second peak of vertical GRF in the terminal stance. These major findings suggest that children with ASD experience significant difficulties in supporting their body weight and endure gait instability during the stance phase. The findings of this research are useful to both clinicians and parents who wish to provide these children with appropriate treatments and rehabilitation programs.
    Matched MeSH terms: Biomechanical Phenomena
  15. 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
  16. Gallagher MT, Cupples G, Ooi EH, Kirkman-Brown JC, Smith DJ
    Hum Reprod, 2019 07 08;34(7):1173-1185.
    PMID: 31170729 DOI: 10.1093/humrep/dez056
    STUDY QUESTION: Can flagellar analyses be scaled up to provide automated tracking of motile sperm, and does knowledge of the flagellar waveform provide new insight not provided by routine head tracking?

    SUMMARY ANSWER: High-throughput flagellar waveform tracking and analysis enable measurement of experimentally intractable quantities such as energy dissipation, disturbance of the surrounding medium and viscous stresses, which are not possible by tracking the sperm head alone.

    WHAT IS KNOWN ALREADY: The clinical gold standard for sperm motility analysis comprises a manual analysis by a trained professional, with existing automated sperm diagnostics [computer-aided sperm analysis (CASA)] relying on tracking the sperm head and extrapolating measures. It is not currently possible with either of these approaches to track the sperm flagellar waveform for large numbers of cells in order to unlock the potential wealth of information enclosed within.

    STUDY DESIGN, SIZE, DURATION: The software tool in this manuscript has been developed to enable high-throughput, repeatable, accurate and verifiable analysis of the sperm flagellar beat.

    PARTICIPANTS/MATERIALS, SETTING, METHODS: Using the software tool [Flagellar Analysis and Sperm Tracking (FAST)] described in this manuscript, we have analysed 176 experimental microscopy videos and have tracked the head and flagellum of 205 progressive cells in diluted semen (DSM), 119 progressive cells in a high-viscosity medium (HVM) and 42 stuck cells in a low-viscosity medium. Unscreened donors were recruited at Birmingham Women's and Children's NHS Foundation Trust after giving informed consent.

    MAIN RESULTS AND THE ROLE OF CHANCE: We describe fully automated tracking and analysis of flagellar movement for large cell numbers. The analysis is demonstrated on freely motile cells in low- and high-viscosity fluids and validated on published data of tethered cells undergoing pharmacological hyperactivation. Direct analysis of the flagellar beat reveals that the CASA measure 'beat cross frequency' does not measure beat frequency; attempting to fit a straight line between the two measures gives ${\mathrm{R}}^2$ values of 0.042 and 0.00054 for cells in DSM and HVM, respectively. A new measurement, track centroid speed, is validated as an accurate differentiator of progressive motility. Coupled with fluid mechanics codes, waveform data enable extraction of experimentally intractable quantities such as energy dissipation, disturbance of the surrounding medium and viscous stresses. We provide a powerful and accessible research tool, enabling connection of the mechanical activity of the sperm to its motility and effect on its environment.

    LARGE SCALE DATA: The FAST software package and all documentation can be downloaded from www.flagellarCapture.com.

    LIMITATIONS, REASONS FOR CAUTION: The FAST software package has only been tested for use with negative phase contrast microscopy. Other imaging modalities, with bright cells on a dark background, have not been tested but may work. FAST is not designed to analyse raw semen; it is specifically for precise analysis of flagellar kinematics, as that is the promising area for computer use. Flagellar capture will always require that cells are at a dilution where their paths do not frequently cross.

    WIDER IMPLICATIONS OF THE FINDINGS: Combining tracked flagella with mathematical modelling has the potential to reveal new mechanistic insight. By providing the capability as a free-to-use software package, we hope that this ability to accurately quantify the flagellar waveform in large populations of motile cells will enable an abundant array of diagnostic, toxicological and therapeutic possibilities, as well as creating new opportunities for assessing and treating male subfertility.

    STUDY FUNDING/COMPETING INTEREST(S): M.T.G., G.C., J.C.K-B. and D.J.S. gratefully acknowledge funding from the Engineering and Physical Sciences Research Council, Healthcare Technologies Challenge Award (Rapid Sperm Capture EP/N021096/1). J.C.K-B. is funded by a National Institute of Health Research (NIHR) and Health Education England, Senior Clinical Lectureship Grant: The role of the human sperm in healthy live birth (NIHRDH-HCS SCL-2014-05-001). This article presents independent research funded in part by the NIHR and Health Education England. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The data for experimental set (2) were funded through a Wellcome Trust-University of Birmingham Value in People Fellowship Bridging Award (E.H.O.).The authors declare no competing interests.

    Matched MeSH terms: Biomechanical Phenomena
  17. Lussiana T, Patoz A, Gindre C, Mourot L, Hébert-Losier K
    J Exp Biol, 2019 03 18;222(Pt 6).
    PMID: 30787136 DOI: 10.1242/jeb.192047
    A lower duty factor (DF) reflects a greater relative contribution of leg swing versus ground contact time during the running step. Increasing time on the ground has been reported in the scientific literature to both increase and decrease the energy cost (EC) of running, with DF reported to be highly variable in runners. As increasing running speed aligns running kinematics more closely with spring-mass model behaviours and re-use of elastic energy, we compared the centre of mass (COM) displacement and EC between runners with a low (DFlow) and high (DFhigh) duty factor at typical endurance running speeds. Forty well-trained runners were divided in two groups based on their mean DF measured across a range of speeds. EC was measured from 4 min treadmill runs at 10, 12 and 14 km h-1 using indirect calorimetry. Temporal characteristics and COM displacement data of the running step were recorded from 30 s treadmill runs at 10, 12, 14, 16 and 18 km h-1 Across speeds, DFlow exhibited more symmetrical patterns between braking and propulsion phases in terms of time and vertical COM displacement than DFhigh DFhigh limited global vertical COM displacements in favour of horizontal progression during ground contact. Despite these running kinematics differences, no significant difference in EC was observed between groups. Therefore, both DF strategies seem energetically efficient at endurance running speeds.
    Matched MeSH terms: Biomechanical Phenomena
  18. Panagiotopoulou O, Iriarte-Diaz J, Wilshin S, Dechow PC, Taylor AB, Mehari Abraha H, et al.
    Zoology (Jena), 2017 10;124:13-29.
    PMID: 29037463 DOI: 10.1016/j.zool.2017.08.010
    Finite element analysis (FEA) is a commonly used tool in musculoskeletal biomechanics and vertebrate paleontology. The accuracy and precision of finite element models (FEMs) are reliant on accurate data on bone geometry, muscle forces, boundary conditions and tissue material properties. Simplified modeling assumptions, due to lack of in vivo experimental data on material properties and muscle activation patterns, may introduce analytical errors in analyses where quantitative accuracy is critical for obtaining rigorous results. A subject-specific FEM of a rhesus macaque mandible was constructed, loaded and validated using in vivo data from the same animal. In developing the model, we assessed the impact on model behavior of variation in (i) material properties of the mandibular trabecular bone tissue and teeth; (ii) constraints at the temporomandibular joint and bite point; and (iii) the timing of the muscle activity used to estimate the external forces acting on the model. The best match between the FEA simulation and the in vivo experimental data resulted from modeling the trabecular tissue with an isotropic and homogeneous Young's modulus and Poisson's value of 10GPa and 0.3, respectively; constraining translations along X,Y, Z axes in the chewing (left) side temporomandibular joint, the premolars and the m1; constraining the balancing (right) side temporomandibular joint in the anterior-posterior and superior-inferior axes, and using the muscle force estimated at time of maximum strain magnitude in the lower lateral gauge. The relative strain magnitudes in this model were similar to those recorded in vivo for all strain locations. More detailed analyses of mandibular strain patterns during the power stroke at different times in the chewing cycle are needed.
    Matched MeSH terms: Biomechanical Phenomena
  19. Mehdizadeh S
    Gait Posture, 2018 Feb;60:241-250.
    PMID: 29304432 DOI: 10.1016/j.gaitpost.2017.12.016
    The largest Lyapunov exponent (LyE) is an accepted method to quantify gait stability in young and old adults. However, a range of LyE values has been reported in the literature for healthy young and elderly adults in normal walking. Therefore, it has been impractical to use the LyE as a clinical measure of gait stability. The aims of this systematic review were to summarize different methodological approaches of quantifying LyE, as well as to classify LyE values of different body segments and joints in young and elderly individuals during normal walking. The Pubmed, Ovid Medline, Scopus and ISI Web of Knowledge databases were searched using keywords related to gait, stability, variability, and LyE. Only English language articles using the Lyapunov exponent to quantify the stability of healthy normal young and old subjects walking on a level surface were considered. 102 papers were included for full-text review and data extraction. Data associated with the walking surface, data recording method, sampling rate, walking speed, body segments and joints, number of strides/steps, variable type, filtering, time-normalizing, state space dimension, time delay, LyE algorithm, and the LyE values were extracted. The disparity in implementation and calculation of the LyE was from, (i) experiment design, (ii) data pre-processing, and (iii) LyE calculation method. For practical implementation of LyE as a measure of gait stability in clinical settings, a standard and universally accepted approach of calculating LyE is required. Therefore, future studies should look for a standard and generalized procedure to apply and calculate LyE.
    Matched MeSH terms: Biomechanical Phenomena
  20. Perera CK, Gopalai AA, Gouwanda D, Ahmad SA, Salim MSB
    Sci Rep, 2023 Oct 03;13(1):16640.
    PMID: 37789077 DOI: 10.1038/s41598-023-43148-0
    Forward continuation, balance, and sit-to-stand-and-walk (STSW) are three common movement strategies during sit-to-walk (STW) executions. Literature identifies these strategies through biomechanical parameters using gold standard laboratory equipment, which is expensive, bulky, and requires significant post-processing. STW strategy becomes apparent at gait-initiation (GI) and the hip/knee are primary contributors in STW, therefore, this study proposes to use the hip/knee joint angles at GI as an alternate method of strategy classification. To achieve this, K-means clustering was implemented using three clusters corresponding to the three STW strategies; and two feature sets corresponding to the hip/knee angles (derived from motion capture data); from an open access online database (age: 21-80 years; n = 10). The results identified forward continuation with the lowest hip/knee extension, followed by balance and then STSW, at GI. Using this classification, strategy biomechanics were investigated by deriving the established biomechanical quantities from literature. The biomechanical parameters that significantly varied between strategies (P 
    Matched MeSH terms: Biomechanical Phenomena
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