Annals of Biomedical Engineering最新文献

Purpose: The kinematic benefits of arm swing during running for upper body stability have been previously investigated, while its role in metabolic energy efficiency remains controversial. To address this, this study aimed to test the hypothesis that active arm swing during running reduces both torso angular motion around the longitudinal axis and metabolic energy consumption.

Methods: We employed forward dynamics musculoskeletal running simulations with different arm conditions to investigate the hypothesis. Full-body musculoskeletal running models, incorporating 150 muscles, were developed using artificial neural network-based running controllers. Three arm conditions were simulated using the running models and controllers: active arm swing, passive arm swing, and fixed arms.

Results: Our results revealed that the active arm swing model demonstrated the lowest total metabolic energy consumption per traveling distance. The costs of transport were 5.52, 5.73, and 5.82 J/kg-m for active, passive, and fixed arm models, respectively. Interestingly, while metabolic energy consumption in the upper limb muscles was higher during active arm swing, the total energy consumption was lower. Additionally, the longitudinal rotation of the torso was minimal in the active arm swing condition.

Conclusion: These findings support our hypothesis, demonstrating that active arm swing during running reduces the angular motion of the torso and the metabolic energy consumption. This study provides evidence that arm swing during running is performed actively as an energy-saving mechanism. These results contribute to understanding of running biomechanics and may have implications for performance optimization in sports and rehabilitation settings.

Purpose: This study aimed to explore whether mechanical load features, including the magnitude of the medial knee contact force (KCFmed) and its center of pressure (KCFcop) during gait, predict future surgery in patients with knee osteoarthritis (OA).

Methods: Twenty-six patients with knee OA walked three times at a comfortable speed, and the external knee adduction moment (KAM), flexion moment (KFM), and total knee moment of the KAM and KFM (KTM) were assessed. We further evaluated KCFmed and KCFcop using a musculoskeletal model. The values of knee moments and KCFmed were extracted at the first and second peaks, and the average KCFcop location and amount of KCFcop displacement were calculated during the early-, mid-, and late-stance phases. Ten years after data collection, we confirmed whether the patients required knee surgery (Surg_OA) or not (NonSurg_OA).

Results: Twenty-four patients with complete data were divided into Surg_OA and NonSurg_OA groups. The Surg_OA group had significantly lower KTM, KFM, and KCFmed values at the first peak than the NonSurg_OA group. In the Surg_OA group, KCFcop shifted toward the joint center during the mid- and late-stance phases, and the amount of KCFcop displacement was small during the mid-stance phase. No significant differences were observed in the other parameters.

Conclusion: Our findings demonstrated that individuals who underwent knee surgery within 10 years showed suppressed KCFmed magnitudes in the first half of the stance phase, whereas they received sustained force on a localized area of the medial compartment during the mid-stance phase.

Titanium (Ti)-based materials are favored for hard tissue applications, yet their bioinertness limits their success. This study hypothesizes that functionalizing Ti materials with chitosan nano/microspheres and calcitriol (VD) will enhance their bioactivity by improving cellular activities and mineralization. To test this, chitosan particles were applied uniformly onto Ti surfaces using electrophoretic deposition (EPD) at 20 V for 3 minutes. VD was then loaded onto the coated surfaces, and the release profile of VD was monitored. Human fetal osteoblastic cells (hFOB) were cultured on the VD-loaded Ti surfaces. Cellular activities such as proliferation, Alkaline phosphatase (ALP) activity, osteogenic gene expression (runt-related transcription factor 2 (Runx2), collagen type 1 (Col I), osteocalcin ( OCn), osteopontin (OP)), and mineralization were assessed. Von Kossa staining was performed to analyze mineralization, and the expression of cell adhesion proteins (N-cadherin (NC), integrin alpha V (IaV), integrin beta 3, (Ib3)) was measured. The results showed that approximately 50% of the VD released over 50 hours. The chitosan coating increased surface roughness three-fold, and this, combined with VD release, resulted in reduced cell proliferation but increased ALP activity, suggesting enhanced differentiation. VD-functionalized Ti surfaces showed statistically significant differences in osteogenic gene expressions, particularly on rougher surfaces. Additionally, the expression of cell adhesion proteins (NC, IaV, Ib3) was upregulated on VD-containing coated surfaces. Von Kossa analysis revealed that surface roughness significantly enhanced mineralization, particularly on VD-free surfaces by day 7, while mineralization on VD-containing bare surfaces started on day 14. These findings demonstrate that VD-loaded chitosan coatings significantly enhance the biocompatibility and bioactivity of Ti-based materials, highlighting their potential for applications in bone regeneration.

Extracorporeal Membrane Oxygenation (ECMO) is a modality of extracorporeal life support which allows temporary support in cases of cardiopulmonary failure and cardiogenic shock. This study presents a valveless pump that works by the Liebau effect as a possible pumping system in ECMO circuits, replacing the current roller and centrifugal pumps. For this purpose, a mock circulatory loop emulating the haemodynamic of the right part of the heart has been constructed. A veno-venous ECMO circuit with the integrated Liebau pump has been incorporated to analyse its performance. The Liebau pump in the ECMO circuit showed a flow assistance in the range of paediatric ECMO and low blood flow range for adults. In addition, experimental tests conducted demonstrated the advantage of the Liebau pump over currently used pumps as the ability to generate a pulsatile flow, which has many advantages in biomedical applications.

Purpose: To evaluate the mechanical wear of cartilage with different types of degradation.

Methods: Bovine osteochondral explants were treated with interleukin-1β (IL-1β) to mimic inflammatory conditions, with chondroitinase ABC (ChABC) to specifically remove glycosaminoglycans (GAGs), or with collagenase to degrade the collagen network during 5 days of culture. Viscoelastic properties of cartilage were characterized via indentation. Biochemical assays were performed to quantify the cartilage matrix loss to the media during culture and from an accelerated, ex vivo wear test. The coefficient of friction during the wear test was measured. Distribution of GAGs in the tissue was assessed histologically.

Results: All three degradative treatments decreased the cartilage modulus values and depleted GAGs in histological sections. However, wear was not uniform among the different treatments. Collagen loss from the tissue due to mechanical wear was only higher with IL-1β and collagenase treatment, while collagen loss due to wear with ChABC treatment was similar to untreated controls. In addition, less GAG was released due to mechanical wear in all degraded groups than the controls, likely because GAGs had already been depleted from these tissues during culture. As no significant differences in the coefficient of friction were observed between groups, changes in wear were attributed to altered tissue composition and structure rather than to changes in frictional forces.

Conclusions: Results suggest that cartilage with a degraded collagen network is more susceptible to mechanical wear, but that cartilage wear may be relatively unaffected by the loss of GAGs. Furthermore, exacerbated mechanical wear could be an additional mechanism by which inflammatory cytokines induce cartilage breakdown.

Purpose: To evaluate the population variation in head-to-helmet contact forces in helmet users.

Methods: Four different size Kevlar composite helmets were instrumented with contact pressure sensors and chinstrap tension meters. A total number of 89 volunteers (25 female and 64 male volunteers) participated in the study. The length, width, and circumference of their heads were measured and each volunteer was assigned a helmet size. Volunteers were asked to wear the helmet in three different configurations and the chinstrap tension and contact force between the head and each of the seven interior pads were recorded.

Results: The majority of forces measured on any individual pad were between 0 and 5 N. However, some users exhibited pressure points with forces as high as 30 N. The contact force distribution is non-uniform across the interior of the helmet, with the largest force concentrated at the front. Head shape is a major driver of the observed contact force. There was a statistically significant difference between female and male volunteers, and between groups with different experience levels.

Conclusions: The fit of helmet systems is highly subject specific. The current metrics used to assign helmet sizes may not accurately predict correct helmet fit.

Purpose: People with unilateral transtibial amputation experienced a higher incidence of knee osteoarthritis due to abnormal movement patterns. This study aimed to explore alternations in muscle coordination to reduce mechanical burdens in their daily activities.

Methods: Five males with unilateral transtibial amputation were recruited. Two daily activities (level walking and standing up from a chair) were simulated using muscle-driven simulation. Two cost functions were applied: minimising the knee adduction moment and minimising both the knee adduction moment and knee flexion moment. This enabled the identification of altered muscle coordination and any possible changes in kinematic patterns.

Results: For people with unilateral transtibial amputation, reducing knee adduction angles during stance was found effective in reducing knee adduction moments. To mitigate peak contact forces at the intact knee, muscle activations of vasti and gastrocnemius should be decreased, while muscle activations of soleus should be increased during activities of level walking and standing up from a chair.

Conclusion: Our study suggested that minimising knee adduction moments was effective in reducing joint loading during level walking while minimising both knee adduction moments and knee flexion moments was effective during standing up from a chair. Therefore, the alteration of muscle coordination should be carefully designed for different daily activities.

Purpose: Head acceleration events (HAEs) are a growing concern in contact sports, prompting two rugby governing bodies to mandate instrumented mouthguards (iMGs). This has resulted in an influx of data imposing financial and time constraints. This study presents two computational methods that leverage a dataset of video-coded match events: cross-correlation synchronisation aligns iMG data to a video recording, by providing playback timestamps for each HAE, enabling analysts to locate them in video footage; and post-synchronisation event matching identifies the coded match event (e.g. tackles and ball carries) from a video analysis dataset for each HAE, this process is important for calculating the probability of match events resulting in HAEs. Given the professional context of iMGs in rugby, utilising commercial sources of coded match event datasets may expedite iMG analysis.

Methods: Accuracy and validity of the methods were assessed via video verification during 60 rugby matches. The accuracy of cross-correlation synchronisation was determined by calculating synchronisation error, whilst the validity of post-synchronisation event matching was evaluated using diagnostic accuracy measures (e.g. positive predictive value [PPV] and sensitivity).

Results: Cross-correlation synchronisation yielded mean synchronisation errors of 0.61-0.71 s, with all matches synchronised within 3 s' error. Post-synchronisation event matching achieved PPVs of 0.90-0.95 and sensitivity of 0.99-1.00 for identifying correct match events for SAEs.

Conclusion: Both methods achieved high accuracy and validity with the data sources used in this study. Implementation depends on the availability of a dataset of video-coded match events; however, integrating commercially available video-coded datasets offers the potential to expedite iMG analysis, improve feedback timeliness, and augment research analysis.