Acta of bioengineering and biomechanics最新文献

Purpose: The aim of the analysis was to develop design principles for a new material having properties similar to those of the natural aortic artery. This involved replacing the complex structure of the aortic wall with a new material with a layer-composite structure having the same strength and hemodynamic properties. The structure of the material used to construct the new aortic prosthesis consists of three layers. The fibers in inner layer were embedded in a liquid matrix, which does not degrade or change its properties in contact with the moving fiber. Methods: The FEM was used to develop the strength properties of the new material. Constitutive equations were defined to relate the state of stress and the state of strain in the material. Based on the results of the identification process, a material specimen was prepared. Due to the orthotropic properties of the material. In the experimental studies, a specimen developed for the circumferential direction was tested. Results: In the circumferential direction, the Young's modulus was 1090 kPa, and the fiber shape factor was 0.056. In the axial direction, the Young's modulus was 440 kPa, the fiber shape factor was 0.067. Conclusions: The paper presents the process of optimizing the material model of a new bioprosthesis, which mechanically imitates the natural material of the aorta. A simple fiber structure was immersed in a liquid matrix and described using basic material parameters. This approach allows to obtain a material with non-linear characteristics and high compliance.

Purpose: The purpose of this study was to investigate the effects of foot strike patterns and running-induced fatigue on the biomechanical responses of the knee and ankle joints in amateur marathon runners by analyzing the combined effects of these two factors on lower limb joint kinematics, kinetics, and muscle activation characteristics under different conditions. Methods: A total of 26 participants were recruited.13 male amateur marathon runners with habitual non-rearfoot strike and 13 with rearfoot strike patterns underwent mild, moderate and severe running-induced fatigue interventions. Kinematic, ground reaction force and electromyographic data were collected. A two-way analysis of variance was performed in SPSS for statistical analysis. Results: Fatigue level significantly affected knee joint range of motion ( p = 0.023), peak joint moment ( p = 0.003), and joint stiffness ( p = 0.040). The non-rearfoot strike runners exhibited significantly greater ankle joint range of motion ( p < 0.001) and lower peak joint moments ( p < 0.001) compared to rearfoot strike runners. A significant interaction effect between fatigue and foot strike pattern was observed on the Root Mean Square amplitude of the medial gastrocnemius ( p = 0.017) and biceps femoris ( p = 0.021). Conclusions: A significant interaction effect between fatigue and foot strike patterns was observed in Root Mean Square. Given the impact of localized muscle fatigue on joint kinematics and kinetics, the nonrearfoot strike runners may demonstrate intense fatigue-related biomechanical alterations to the knee and ankle joints during the latter stages of long-distance running. These results suggest that understanding foot strike biomechanics under fatigue may inform training and injury prevention.

Purpose: Increased physical load on the body of American football players, especially in the lower limbs, may be associated with increased risk of foot deformities and injuries, potentially influencing players' overall fitness and performance. The aim of the study was to assess the relationship between American football training, training duration and anthropometric features, and foot posture in Polish players. Methods: 70 athletes training American football in Poland and 35 non-training. The study used a questionnaire and the Foot Posture Index - 6 to assess foot shape. An analysis of the relationship between age, Body Mass Index and training experience with foot posture was conducted. Results: The average BMI value between the studied groups of athletes and non-training was significantly different ( p < 0.01). The athletes and non-training participants showed good foot posture according to the total Foot Posture Index - 6, but a statistically significant difference between the groups was found in all partial values of the Foot Posture Index measurements 1-6, except for Foot Posture Index 2, left foot. In the group of athletes, no statistically significant relationship was found between anthropometric parameters and Body Mass Index and Foot Posture Index - 6. In the non-training participants, a significant relationship ( p < 0.02) was found between the shape of the left foot and BMI. Conclusions: Monitoring foot posture and BMI in athletes practicing American football may be beneficial. Based on the observed tendency toward foot pronation, football players may benefit from individually selected footwear, including anti-pronation options when indicated.

Purpose: This study aimed to develop feature extraction strategies for Center of Pressure (CoP) signals using adaptive genetic programming to characterize fall risk in older adults. Methods: The individual performance of CoP indices reported in the state-of-the-art was optimized through adaptive genetic programming across mathematical domains, such as entropy, time-based (distance, area, hybrid measures) and frequency-based ones. The validity of the new CoP indices was tested using mean difference tests for groups with and without fall risk, measuring the correlation with existing measures, as well as through the performance of univariate and multiple logistic regressions, which were reported in terms of the macro-average F1-score, recall, accuracy, specificity, sensitivity, and Area Under the Curve (AUC). Results: The newly generated genetic CoP indices outperformed state-of-the-art indices in fall risk identification. The genetic-frequency CoP index achieved the best performance in univariate logistic regression, with an AUC of 0.763 using five-fold cross-validation. Moreover, all genetic indices showed statistically significant differences between older adults with and without fall risk. Conclusions: These results suggest that the proposed methodology provides some simple calculation formulas that facilitate its future adoption in clinical settings and increase fall risk classification performance by up to 27.0%.

Purpose: To examine the relationship between the frontal plane alignment of the lower extremity, adductor longus muscle architecture (cross-sectional area and thickness), and anaerobic power capacity. Methods: Football players aged 14-16 joined the study and were evaluated for lower extremity alignment in the frontal plane radiographs. We examined adductor longus muscle thickness and cross-sectional area on both sides with ultrasound. To evaluate anaerobic power capacity, we did a 30-second Wingate test. Correlation analysis and multiple regression analysis were performed. Results: 27 football players were enrolled in the study. The anatomical axis angle of the right side was 2.85 ± 1.75, and left side was 2.67 ± 1.62. A positive and strong correlation was found between both side muscle cross-sectional area and maximum and average power (right: r = 0.829, p < 0.001; r = 0.851, p < 0.001, left: r = 0.742, p < 0.001; r = 0.789, p < 0.001, respectively), and the right and left muscle thickness and the maximum and average power (right: r = 0.678, p < 0.001; r = 0.717, p < 0.001, left: r = 0.714, p < 0.001; r = 0.741, p < 0.001, respectively). The multiple regression analysis found that average power could be assessed with right and left axis angles, right muscle cross-sectional area, age, body mass index, and career duration. The analysis showed that these variables accounted for 80.3% of the variability in the average power (F (6,20) =13.558, p < 0.001). Same independent variables could explain 77.6% of the variability in the maximum power (F (6,20) = 11.577, p < 0.001). Conclusions: Muscle thickness and cross-sectional area strongly correlate with average and maximum power. The cross-sectional area and lower extremity alignment angle in the dominant leg could be used to estimate anaerobic power outputs.

Purpose: The aim of this study was to evaluate absorbable and non-absorbable surgical sutures exposed to an environment with a chemical composition similar to that of ocular body fluids. Methods: The evaluation was based on the results of tests of the mass, diameter and mechanical properties of samples immersed in physiological saline solution (BSS) at different time intervals. Results: Based on the conducted research, it was found that multifilament threads made of PGCL dissolve the fastest under these conditions, while PDS monofilament threads dissolve the longest. In the first case, the last measurements could be taken after 14 days of immersion, while in the second case, the mono-filament was not completely dissolved even after 80 days. Conclusions: Despite numerous publications in this area, available from various sources, it is very difficult to compare the obtained results to those of other authors. This is due to the fact that studies conducted on threads made of different materials and diameters, as well as in different environments, can have a significant impact on the resorption process. This justifies the need for this type of research.

Purpose: This study aimed to compare the efficacy of four contemporary retreatment file systems, i.e., R-Endo, XP-Endo Retreatment, HyFlex Remover, and MicroMega Remover, in the solvent-free removal of aged bioceramic sealers from root canals, and to elucidate the relationship between file design and retreatment performance using advanced micro-computed tomography (micro-CT). Methods: 40 extracted human mandibular premolars with single straight canals were prepared and obturated using either Total Fill BC or BioRoot RCS sealers, then aged for one year. Specimens were randomly assigned to four retreatment file systems (n = 5 per subgroup), and retreatment was performed without solvents according to manufacturers' protocols. Residual filling material was quantified pre- and post-retreatment using micro-CT. Data were analyzed with repeated-measures analysis of variance. Results: XP-Endo Retreatment and HyFlex Remover showed superior removal efficiency, particularly in middle and cervical thirds (>84%), whereas R-Endo consistently exhibited the lowest performance, especially apically. MicroMega Remover demonstrated intermediate efficacy, outperforming R-Endo but less effective than XP-Endo Retreatment and HyFlex. No significant differences were observed between Total Fill BC and BioRoot RCS sealers. Results indicated significant effects of canal third and file system ( p < 0.001) and a significant canal third × file system × sealer interaction ( p = 0.037). Conclusions: File design and metallurgical properties significantly influence the mechanical retrievability of aged calcium silicate-based sealers in solvent-free retreatment. XP-Endo Retreatment and HyFlex Remover provided superior cleaning under in vitro conditions. These findings inform clinicians on the selection of retreatment instruments for predictable removal of bioceramic sealers.

Purpose: The aim of this study was an exploration of the multiscale vibratory response of the spine following orthopedic surgery in patients with idiopathic scoliosis and postoperative traumatic fatigue injury. Methods: In this paper, the postoperative macroscopic spine model in the modal, time and frequency domains to obtain the vibration response of the patient's entire spine were analyzed. Subsequently, the stresses in the cortical bone mesoscopic bone units around the surgically damaged interface were calculated using submodeling algorithms. The pore stresses and pore flow velocities of the osteocytes were then derived from the stresses of the mesoscopic bone units to predict fatigue damage at the fusion surface. Results: The findings indicated that the first three orders of intrinsic frequency exerted the most significant influence on the spine model. The maximum stress of the bone unit was observed at the X3 bone plate on the left side of the fusion surface, and the maximum pore pressure and flow velocity of the bone cells occurred at the X4 on the right side of the fusion surface. The medical implants used in spinal orthopedics, titanium cages and pedicle nails, change the mobility of the adjacent segments and also create a stress shielding effect that impacts the fusion of bone tissues. Conclusions: Microscopic bone cell synapses experience greater pore pressures and pore flow velocities in the vibration environment compared to those under the static environment, which may promote cell growth. Vibration at low loads typically does not induce fatigue damage to cancellous bone at the fusion surface of medical implants.

Purpose: The aim of this study was to determine the relationship between anthropometric indices and kinematic underwater undulatory swimming (UUS) variables among young female swimmers. Methods: The following parameters were determined in 34 participants (age 16.74 ± 0.70 years, World Aquatics score 561 ± 64): body height (H), mass (M) and fat percentage (B_F ), BMI, lengths of the lower limb (L_L ), thigh (L_T ), and calf (L_C ), circumferences of thigh (C_T ), maximum calf (C_{C MAX}) and distal lower leg (C_CDIS ), skinfolds on the thigh (F_T ) and calf (F_C ), as well as foot length (F_L ) and width (W_F ), based on which an estimated foot surface area was calculated (S_F ). Using the kinematic analysis of UUS recordings, the following were determined: velocity (v), frequency ( f ), distance per cycle (DPC), amplitude of toe (A) and product of A × f (I_Af ). Pearson r correlation analysis was performed. Results: A relationship was observed between v and: C_{C MAX} (r = 0.48), C_CDIS (r = 0.39) and L_F (r = 0.35). I_Af was correlated with: C_CDIS (r = 0.40), C_{C MAX} (r = 0.39) and M (r = 0.35). A relationship was observed between A and F _T (r = 0.45) and C _T (r = 0.42), as well as DPC with F_T (0.40) and C_{C MAX} (0.37). Conclusions: The results indicate that the somatic structure has a small effect on the effectiveness and kinematic indices of UUS among young female swimmers.

Purpose: The present study aimed to assess physical performance and its relationship with age and BMI in young male football players with Down syndrome and mild intellectual disability compared to their untrained peers. Methods: The study included 60 boys with Down syndrome and mild intellectual disability aged 11-13 years, assigned to the study group (trained football at the Futbol+ Sports Academy) and the control group (untrained peers). Research tools was the Eurofit Special test. The data were analyzed based on the using chi-squared test, Student's t-test for independent variables, or Mann-Whitney U-test, Pearson's linear correlation or Spearman's rank correlation. Results: Young male football players with Down syndrome scored better for Standing Long Jump ( p < 0.001), Bent Knee Sit-ups in 30 seconds ( p < 0.001), 2 kg Medicine Ball Forward Push with one hand ( p < 0.001), and Walking on a Gymnastic Bench in the Upright Position ( p = 0.001), while for 25 m Run from a High Start, boys from the control group achieved better results ( p < 0.001). There were no statistically significant relationships of Eurofit Special test results with age and BMI. Conclusions: Football training improves physical performance of boys with Down syndrome and mild intellectual disability, especially dynamic balance, muscle strength of the lower limbs, upper limbs and abdomen. It can therefore be assumed that these characteristics are the most important indicators of the effectiveness of football training in these individuals. Age and BMI should not be considered as determinants of motor fitness in children and adolescents with Down syndrome and associated mental retardation.