Acta of bioengineering and biomechanics最新文献

Purpose: This study evaluated changes in selected spatiotemporal and kinematic gait parameters and balance in girls with Adolescent idiopathic scoliosis (AIS) with and without the Chêneau brace. Methods: 15 subjects with scoliosis wearing the Chêneau brace and an equal comparative control group underwent objective gait analysis with the 3D BTS motion caption system. Balance assessment was done with the Kistler platform. The analysis was performed at comparison of gait and balance parameters in patients with scoliosis in two conditions: with and without the Chêneau brace during the study. Results: Statistically significant differences occurred in many spatiotemporal and kinematic parameters both for the AIS group with and without the Chêneau brace and in the AIS group with and without the Chêneau brace as compared to the control group. When comparing adolescents with AIS with and without the Chêneau brace, statistically significant differences were noted in the COP-X amplitude and in the path length in trials with closed eyes. Compared to the control group the following differences were statistically significant: the value of the COP-Y amplitude during the trial with closed eyes, both with and without the Chêneau brace, and the Equivalent area of the COP during the trial with closed eyes with the Chêneau brace. Conclusions: The Chêneau brace in patients with juvenile idiopathic scoliosis affects the level of selected balance and gait parameters.

Purpose: The aim of this study was to investigate the effect of substrate - polycaprolactone (PCL)-based porous membrane modified with rosmarinic acid (RA), (PCL-RA) and to determine the optimal values of low field laser irradiation (LLLT) as stimulators of biological response of RAW 264.7 macrophages. Methods: The porous polymer membrane was obtained by the phase inversion method, the addition of rosmarinic acid was 1%wt. The reference material was pure polymer membrane. RAW 264.7 were deposited on the material and then irradiated with a laser with a wavelength of 808 nm, a power of 100 mW, an irradiation dose of 2 J/cm2/cell well, applied continuously (C), (100/2/C) or pulsed (I), (100/2/I). Results: Macrophage irradiation resulted in an increase in their adhesion. Modifying the PCL membranes with rosmarinic acid had no effect on cell viability on day 3 of the cell culture. Irradiation of macrophages cultured on PCL-RA material increased their viability. Irradiation of macrophages cultured on PCL-RA material decreased macrophage secretion of NO and protein and the increase in TNF and MCP-1 secretion was only transient on day 3 of culture. Conclusions: Macrophage irradiation had a positive effect on macrophage attachment. Modification of PCL membranes with rosmarinic acid influenced the biological activity of macrophages. Culture of macrophages on rosmarinic acid-modified PCL membranes and simultaneous irradiation of LLLT cells resulted in anti-inflammatory effects.

Purpose: The impact of shoe stiffness on running biomechanics is well-documented, while the specific effect on the performance of biomechanically distinct groups such as novice runners and experienced runners is still largely unexplored. The study aimed to evaluate the biomechanical effect of different shoe longitudinal bending stiffness on the lower limb during running in novice runners and experienced runners. Methods: Twelve experienced runners and ten novice runners ran at a speed of 4.47 m/s while randomly wearing shoes with either low stiffness (5.9 Nm/rad) or high stiffness (8.6 Nm/rad). An Opensim musculoskeletal model was adopted for estimating lower limb joint angles, joint angular velocities, joint moment, joint work, peak joint reaction forces during running stance phase. Results: Results showed that novice runners displayed greater lower limb joint angles and less joint moment, while experienced runners exhibited reduced joint angles but greater joint moment, and higher peak joint reaction forces were observed at the knee and ankle joints. Furthermore, increased shoe longitudinal bending stiffness resulted in higher peak joint reaction forces at the metatarsophalangeal joint for novice runners while lower for experienced runners. Conclusions: Novice runners exhibit greater lower limb joint angles and reduced joint moments compared to experienced runners. Increased longitudinal bending stiffness results in higher peak joint reaction forces at the metatarsophalangeal joint for novice runners, while experienced runners show reduced forces under the same conditions. This nuanced understanding of joint dynamics underscores the need for tailored training and footwear recommendations specific to different levels of running experience.

Purpose: Caries or iatrogenic thermal trauma of the teeth have a significant impact on the dental pulp structure connected with stimulation of angiogenesis and lymphangiogenesis. Therefore, the aim of the study was to identify the difference in the rate of heat dissipation by vessels present in the dental pulp. Methods: Freshly extracted healthy (n = 10) and carious (n = 14) molars and premolars were cut on a diamond saw and subjected to active thermographic examination and then subjected to lymphoscintigraphy and X-ray examination. The tooth samples were heated uniformly to 40 ± 0.5 °C. A thermal imaging camera with a resolution of 640 × 320 pixels was used to record the sequence of thermograms during free cooling. Due to the different volume of teeth and different surface conditions of the examined teeth (color, roughness) and the related different radiation emissivity, the changes in the temperature (ΔT) of the tooth cross-section surface were analyzed using the subtractive method within 120 seconds from the switching off of the thermal impulse (heating). Results: Thermographic examination of healthy and cariously changed teeth revealed areas of increased tissue fluid flow combined with heat release, which may indirectly indicate the existence of vessels in these areas. On a thermal imaging camera, variations in the rate of heating or cooling across several cross-sectional sections of the same tooth indicate changes in the dental structure's density. Conclusions: In caries-affected teeth, intracanalicular fluid flows are different than those of healthy teeth. Therefore, it can be concluded that the pulp vessels enabling circulation of body fluids - blood and lymphatic - increases with the intensity of inflammation. Maintaining the homeostasis of the dental pulp depends heavily on the circulation of bodily fluids within the dental organ.

Transmissibility is used to assess dynamic responses of the occupant-seat system, and most studies have exclusively assessed the transmissibility from the floor to the cushion or the backrest surface with the human body. In this investigation, the vertical vibration transmitted from the floor to six specific locations both on the seat surface and the frame when the seat was fixed on three positions on the track was examined utilizing an SAE J826 manikin and 12 male adults (0.25 to 20 Hz) for a duration of 120 seconds at three vibration amplitudes. The transmissibility from the floor to the headrest frame, the cushion surface, the headrest surface, the seat back frame, and the seat back surface all exhibited a principal peak frequency within 4-5 Hz. With the exception of the cushion frame, the principal peak frequency and the peak transmissibility in transmissibilities to all positions decreased with increasing vibration amplitude, indicating the non-linearity within the occupant-seat system. It was also found modifying seat track positions minimally affected the seat transmissibility to either the surface or the frame of the seat. Polyurethane foam amplified vibration at peak frequency, simultaneously enhancing static sitting comfort and reducing the vertical vibration transmission above peak frequency.

Purpose: Brain tissue immersed in cerebrospinal fluid often exhibits complex mechanical behaviour, especially the nonlinear stress- strain and rate-dependent responses. Despite extensive research into its material properties, the impact of solution environments on the mechanical behaviour of brain tissue remains limited. This knowledge gap affects the biofidelity of head modelling. This study aimed to investigate the effect of solution environments on brain tissue under quasi-static and dynamic loading conditions. Methods: Porcine brain tissue was characterized in compression through quasi-static nonlinear testing and Dynamic Mechanical Analysis under various environments: air, physiological saline and artificial cerebrospinal fluid. Frequencies from 0.1 to 40 Hz were applied to determine dynamic behaviour, while brain samples were compressed up to a 0.3 strain level to obtain nonlinear response. The effects of strain, frequency and solution environment on the mechanical response of brain tissue were statistically evaluated. Results: As environmental conditions transitioned from air to artificial cerebrospinal fluid, the average stress of brain tissue increased by approximately 1.3, 1.3 and 1.4 times at strain levels of 0.1, 0.2 and 0.3, respectively. A statistically significant increase in dynamic storage and loss moduli was observed between air and artificial cerebrospinal fluid environments. At frequencies above 18 Hz, the tan delta in air was significantly lower. Conclusions: The mechanical characterization of brain tissue exhibited a dependency on solution environment under both quasi-static and dynamic loading conditions. Brain tissue showed higher stress levels and dynamic modulus in solution environments compared to an air environment. The results of this study are valuable for improving head simulations and brain material models.

Purpose: Elbow contracture is a common complication post-elbow trauma, the biomechanical environment after anterior capsule injury was complex. This study aimed to use a finite element model to investigate the biomechanical environment within elbow capsule and its surrounding tissues at various stages after anterior capsule injury. Methods: A finite element model of the elbow joint, incorporating muscle activation behavior, was developed to simulate elbow flexion under normal condition (no injury) and at 2, 4, 6 and 8 weeks following anterior joint capsular injury. The model was used to analyze von Mises stress distribution and changes within the elbow tissues. Results: At no injury condition, and 2, 4, 6 and 8 weeks, the stress of the anterior articular capsule at 60° flexion were 2.62, 3.87, 4.40, 4.57 and 5.24 MPa, respectively. Under normal conditions, and at 2, and 4 weeks, the ulnar cartilage attained its peak stress at 75°. In normal conditions, the highest stress in the ulnar cartilage was 1.08 MPa, amounting to 1.02 times and 1.05 times the stress observed at 2 and 4 weeks, respectively. At 4 weeks, compared with 6 weeks, the stress of the anterior bundle at 15, 30, 45 and 60° was reduced by 11.1, 22.6, 37.3 and 36.1%, respectively. At 6 and 8 weeks, the peak stress in the posterior articular capsule reached 11.5 and 11.7 MPa, respectively, showing minimal variation. Conclusions: The results could offer theoretical basis for rehabilitation professionals in treating and preventing elbow capsule contracture.

Soccer is a sport being performed in a very dynamic manner. It requires soccer players to be able to develop high muscle force in a very short period of time. The aim of the study was to evaluate the strength and jumping abilities of young soccer players playing in different positions on the field. The study included 49 adolescent soccer players: 6 goalkeepers, 15 defenders, 17 midfielders and 11 strikers. We measured peak torques (PT), total work (TW), and average power (AP) developed by the knee flexors and extensors under isokinetic conditions at angular velocities of 60°⋅s^-1, 180°⋅s^-1 and 300°⋅s^-1 on a Biodex dynamometer, and jump height (H) and maximum power (P _max) on a force plate. PT, AP, TW, and P _max scores were normalized relative to body mass. There were no statistically significant differences between measurements of basic somatic characteristics (body height and body weight), age and biological age as well as PT, AP, TW, H, and P _max in players from different positions on the field. Unlike defenders, midfielders showed a significant correlation of isokinetic tests indices with jump height (r = 0.54÷0.84) and maximum relative power (r = 0.55÷0.76). The differences in correlations are probably due to the different tasks and activities that players in different positions on the field perform during the game.

Purpose: The aim of the research was to develop the design of a striking dummy and the theoretical foundations of martial arts strikes and to test its effectiveness in a pedagogical experiment. This paper presents the design of a striking dummy and the foundational theories behind martial arts strikes. We used modern microelectronics, including a diverse range of sensors, for executing a multitude of electromechanical measurements. Furthermore, we developed a software package for collecting, analysing and storing data from sports training. Methods: The TaePunchBag program, part of this setup, integrates several combat sports including boxing, taekwondo, kickboxing, karate and hand-to-hand combat. It classifies and evaluates various types of hand and foot strikes, conducting specialized tests to measure attributes such as speed, response to signals, force up to 800 kg and impact accuracy. Results: The article details the tasks and operation of the "Software complex for measuring sportsmen's blows". Additionally, the advanced range of microelectronic sensors supports various electromechanical measurements, further complemented by a software package that handles data collection, analysis and storage from sports training. Conclusions: The application of this sophisticated software system to martial arts strike measurements, particularly in conjunction with a novel punching bag apparatus, may significantly improve our understanding of impact kinetics. This integrated approach is expected to produce accurate and reliable data on punch and kick power, enabling coaches and athletes to refine training strategies and boost their output.

From a current perspective, it is understood that body posture is influenced by individual asymmetries, cultural context, habitual body patterns, etiological factors and psychosocial factors allocated to the individual. Clarifying the musculoskeletal cause that originated the postural alteration is considered the clinical challenge in the treatment of pain or discomfort. Recent studies have shown the influence of changes in body weight on the distribution of plantar pressure and foot pain, emphasizing the importance of understanding these relationships. Integrating body composition with plantar pressure analysis presents an opportunity to explore gender differences and their associations with plantar pressure distribution. There is currently a lack of research integrating body composition, plantar pressure distribution and gender comparison to elucidate the complex interaction between these variables. Therefore, the main objective of this investigation is to evaluate body composition through BIA (bioimpedance) and the distribution of plantar pressure in the subjects' feet through pressure platform analysis with a specific focus on comparisons between the genders and the associations between these variables. The study employed an observational cross-sectional design. A total of 77 participants (n = 77) aged between 18 and 91 years were assessed, the majority of whom were female (n = 53, 68.83%), while 24 participants (n = 24, 31.17%) were male. The average age of the participants was 60.717 years for males and 54.33 years for females. Baropodometry and bioimpedance tests were carried out. Significant differences with a medium effect were recorded only for the three indicators, while the rest of the values showed a large effect. Significant negative correlations were found between age and height ( p < 0.05) and positive correlations between age and other factors such as BMI, fat mass, lean mass and various foot-related metrics. The results of this study showed that plantar pressure characteristics differ according to gender and are related to body composition and pain level.