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    • Computational Fluid Dynamics Analysis on the Disorder of Cerebrospinal Fluid Circulation Induced by the Aqueductal Stenosis
    Xu Zhu , Baopeng Wu , Xiaoyuan Guo , Qiang Chen
    Adopted date: October 24,2024
    [Abstract](1) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Background: The cerebral aqueduct is a narrow channel connecting the third and fourth ventricles, and the aqueductal stenosis can obstruct cerebrospinal fluid (CSF) circulation, resulting in obstructive hydrocephalus. This is associated with intracranial hypertension and clinically manifests as headaches etc. Thus, understanding the effects of varying stenosis degrees of the aqueduct on the intracranial CSF flow field is essential for revealing the pathogenesis of obstructive hydrocephalus. Methods: We utilized clinical MRI image sequences of a male volunteer and semi-automated image segmentation technique to reconstruct a complete normal CSF circulation model. Subsequently, we manually created eight ideal models representing different stenosis degrees of the aqueduct. Computational fluid dynamics (CFD) was then performed to simulate the CSF flow field across all nine models. Results: The stenosis degree of the aqueduct was positively correlated with the maximum pressure difference between the aqueduct upstream and downstream and the maximum velocity of CSF within the stenosed aqueduct. In the normal model, the maximum pressure difference was 0.84 Pa and a maximum CSF velocity 11.4 mm/s. While in the maximum stenosed model, their counterparts were 21.36 Pa and 60.3 mm/s, respectively. This indicated that the maximum pressure difference and the maximum velocity were approximately 25 times and 5 times their counterparts of the normal model, respectively. Moreover, the maximum pressure difference exhibited an exponential relationship with the stenosis area of the aqueduct and a linear relationship with the square of the CSF velocity. Conclusion: The pressure difference and velocity of the stenosed aqueduct was not apparently increased with mild stenosis with respect to the normal aqueduct, while the great aqueductal stenosis increased the risk of hydrocephalus. This study provides a theoretical framework that could be helpful to understand the development of hydrocephalus and intracranial hypertension.
    Analysis of Coordination Patterns and Energy Flow in Patellofemoral Pain Syndrome During Sit-to-Stand Transitions
    li lei , liu xuan , li chen , ni xin di , huang long , liu ye
    Adopted date: October 24,2024
    [Abstract](1) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Objective: To explore limb coordination patterns and energy flow strategies during the Sit-to-Stand (STS) task in individuals with Patellofemoral Pain (PFP), providing theoretical evidence for the pathogenesis of PFP and aiding in the development of treatment and rehabilitation strategies for PFP patients. Methods: This study recruited 36 participants for the STS test, divided into a Unilateral Patellofemoral Pain Group (UPFPG), Bilateral Patellofemoral Pain Group (BPFPG), and a Control Group (CG) based on the number of limbs affected by patellofemoral pain. An infrared motion capture system (Qualisys, Sweden, sampling frequency 200Hz) and a 3D force plate (Kistler, Switzerland, sampling frequency 1000Hz) were used for motion capture. Biomechanical indicators of the trunk, pelvis, and lower limbs were calculated using Visual 3D and Matlab. Coupling angles was used to represent coordination patterns via vector coding; the segmental net energy integration method was used to calculate energy flow within segments at each stage, with positive values indicating energy input and negative values indicating output. Statistical analysis was performed using one-way ANOVA, with a significance level set at 0.05. Results: In the frontal plane coordination pattern, the proximal coordination mode frequency of the pelvis-hip coordination in the FMP phase was higher in UPFPG than in BPFPG (P=0.024). In the MTP phase, the frequency of in-phase coordination in the trunk-pelvis coordination was higher in UPFPG than in BPFPG (P=0.023), while the frequency of distal coordination was higher in CG than in UPFPG (P=0.032). For the knee-ankle coordination pattern, the frequency of distal coordination in CG was lower than that in UPFPG and BPFPG (P=0.025, P=0.005). In segmental energy flow, during the FMP phase, the energy output from the pelvis in MP was higher in BPFPG than in CG (P=0.021). Conclusion: PFP affects energy flow patterns and frontal plane coordination patterns during the STS task. Specifically, individuals in the UPFPG may engage in lateral pelvic and ankle movements as a dynamic compensation for patellofemoral joint pressure, whereas individuals in the BPFPG appear to increase pelvic region energy output and employ a more complex whole-body coordination pattern to compensate for functional deficits in the knee caused by PFP.
    Effect of stent and balloon shape on the hemodynamics in tapered vessels with multiple stenosis
    SHEN Xiang , LIU Qiang , XU Yue , HE Zewen , CHEN Jiahao , JIANG Jiabao , YAN Hengfeng
    Adopted date: October 22,2024
    [Abstract](2) [HTML](0) [PDF 0.00 Byte](0)
    Abstract:
    Objective The influence of stent and balloon shape on hemodynamics was studied in tapered vessels with multiple stenosis. Methods The hemodynamic model was established after the implantation of vascular stent in tapered vessel with multiple stenosis. The numerical simulation method was used to study the effect of the combination of different shaped stents and balloons on postoperative hemodynamics. Results When the cylindrical stent was expanded using cylindrical balloon and tapered balloon respectively, the use of tapered balloon for expansion can produce less low-speed blood flow and low TAWSS areas; When tapered balloon was used to expand cylindrical stent and tapered stent respectively, expanding the cylindrical stent can generate less low-speed blood flow and low TAWSS areas. Conclusions The hemodynamic environment of tapered vessel with multiple stenosis was influenced by the shape of stent and balloon. The use of tapered balloon to expand cylindrical stent in tapered vessels with multiple stenosis can achieve favorable hemodynamic environment and reduce the possibility of ISR.The research conclusion of this paper can provide scientific basis for the rational formulation of clinical intervention scheme.
    Prediction and Clinical Evaluation of Cobb Angle in Idiopathic Scoliosis Using Machine Learning and Mechanical Data from Three Points of 3D-Printed Orthoses
    MA Xunjun , LI Ya , YU Jun , LIU Haitao , WU Yuncheng , WANG Jinwu
    Adopted date: October 21,2024
    [Abstract](4) [HTML](0) [PDF 0.00 Byte](0)
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    ：Objective To develop a Cobb angle prediction model for adolescent idiopathic scoliosis (AIS) based on three-point mechanical data from 3D-printed orthotics and various machine learning algorithms, providing an innovative, radiation-free method for early clinical screening and monitoring of AIS.MethodsClinical data from AIS patients and mechanical data from 3D-printed orthotics were collected to construct a comprehensive dataset with features such as gender, age, disease type, weight, and Risser score. Using six algorithms—Random Forest, Support Vector Regression, Gradient Boosting, and others—to construct and evaluate the performance of Cobb angle prediction models.ResultsThe Gradient Boosting model outperformed others in terms of accuracy, precision, and F1-Score, while the CatBoost model also showed excellent performance in accuracy and AUC. The Gradient Boosting model achieved an accuracy of 0.942, fitting well with the actual Cobb values.Conclusion The Cobb angle prediction model based on mechanical data and machine learning effectively avoids the radiation risks associated with traditional full-spine X-ray examinations in early clinical screening. It provides a non-invasive assessment for AIS patients, enhancing the safety and efficiency of screening and monitoring, and offering a powerful decision-making tool for clinicians, with significant clinical implications.
    Effect of Exercise Fear on Lower Limb Muscle Activation in Patients with Knee Osteoarthritis
    DUAN Bixuan , ZHANG Yuxuan , MA Pei , LI Wei
    Adopted date: October 21,2024
    [Abstract](7) [HTML](0) [PDF 0.00 Byte](0)
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    Abstract: Objective This study applied surface electromyography (sEMG) to analyze muscle activation intensity in patients with knee osteoarthritis (KOA) during physical activity and investigated the impact of exercise-related fear on lower limb muscle function in these patients. Methods A total of 30 KOA patients were selected and categorized into a high-fear group (n = 16) and a low-fear group (n = 14) based on the TSK-17 scale (Tampa Scale for Kinesiophobia) scores, with 14 healthy individuals serving as the control group. A wireless sEMG system recorded muscle activity in the bilateral rectus femoris, vastus medialis, vastus lateralis, biceps femoris, semitendinosus, tibialis anterior, and the medial and lateral heads of the gastrocnemius. Test activities included walking at normal speed, stair ascent, and stair descent. Muscle activation was normalized to maximal voluntary contraction (MVC) by calculating the root mean square (RMS) of the EMG signals to compare muscle activation under different conditions. Correlation analyses were conducted to evaluate the relationship between muscle activation and TSK-17 scores. Results A total of 30 KOA patients were selected and categorized into a high-fear group (n = 16) and a low-fear group (n = 14) based on the TSK-17 scale (Tampa Scale for Kinesiophobia) scores, with 14 healthy individuals serving as the control group. A wireless sEMG system recorded muscle activity in the bilateral rectus femoris, vastus medialis, vastus lateralis, biceps femoris, semitendinosus, tibialis anterior, and the medial and lateral heads of the gastrocnemius. Test activities included walking at normal speed, stair ascent, and stair descent. Muscle activation was normalized to maximal voluntary contraction (MVC) by calculating the root mean square (RMS) of the EMG signals to compare muscle activation under different conditions. Correlation analyses were conducted to evaluate the relationship between muscle activation and TSK-17 scores. Results: In normal walking, the high-fear group's healthy side showed significantly greater activation in the rectus femoris (35.32±20.82 vs. 27.32±12.20, P=0.02), vastus medialis (43.57±23.30 vs. 30.33±13.54, P<0.01), and vastus lateralis (52.89±34.44 vs. 38.25±22.51, P<0.01) compared to the affected side. Similarly, muscle activation was elevated during stair ascent in the high-fear group, with significant differences in the rectus femoris (32.03±14.26 vs. 22.91±11.42, P<0.01), vastus medialis (43.93±18.35 vs. 29.14±16.57, P<0.01), and vastus lateralis (55.45±27.88 vs. 36.00±25.47, P<0.01). Furthermore, in the high-fear group, the affected side exhibited significantly increased activation in the rectus femoris during normal walking compared to the low-fear group and controls. Correlation analysis revealed a significant positive association between TSK-17 scores and rectus femoris activation on the healthy side during stair descent (r=0.952, P<0.01).Conclusions Exercise-related fear has a significant impact on muscle activation patterns in KOA patients, particularly during stair descent, which places greater functional demand on the lower limbs. These findings underscore the importance of addressing psychological factors in KOA rehabilitation to improve both motor function and quality of life comprehensively.
    LI Guibing, WangXinyu, XU Shengkang, LI Kui, QIU Jinlong
    Li Guibing , Wang Xinyu , Xu Shengkang , Li Kui , Qiu Jinlong
    Adopted date: October 21,2024
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    Objective The purpose of the current study is to explore the frequency domain characteristics of pedestrian head dynamic response in vehicle collisions and to investigate the correlation between frequency domain parameters and time domain injury criteria. Methods Finite element modelling based on a human body model was used to simulate the process of pedestrian head-to-vehicle impacts and the wavelet packet signal analysis method was employed to obtain the frequency domain response of pedestrian head in the simulations. Results The head energy in impacts at the hood area is mainly dispersed in the 0-300Hz frequency band, while the head energy in contacts at the windshield area is mainly concentrated in the 0-5Hz frequency band. The peak energy of frequency band for pedestrian head generally increases with the increase of linear and rotational speed, and the influence of rotational speed on the peak energy of frequency band is more significant when the linear speed is higher. The linear correlation R2 values between the peak energy of the head frequency band caused by the collision between the hood and windshield area and the time-domain criterion for skull injury are 0.85 and 0.61, respectively. But their correlation with the time-domain indicators for brain injury evaluation is relatively low (R2<0.5). Conclusions The frequency domain response characteristics of pedestrian heads are affected by collision speed and position. The peak energy of the frequency band can potentially characterize the risk of skull injury, but the frequency band and concentration of the peak energy of the frequency band are not related to the risk of head injury. The results of this study can provide basic reference for the evaluation of head blunt injury combined with time-frequency response.
    The Immediate Impact of Acute Visual Acuity Decline on the Gait of Hemiplegic Patients
    Leng HongShuai , Meng QingHua , Zhou LuXing , Zhang Nan , Deng YiJie
    Adopted date: October 21,2024
    [Abstract](3) [HTML](0) [PDF 0.00 Byte](0)
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    Objective To investigate the immediate impact of changes in kinematic and dynamic characteristics before and after visual intervention on the gait of hemiplegic patients. Methods Thirty visually normal hemiplegic patients were recruited. Recruit 30 hemiplegic patients with normal vision, select plane mirrors with different refractive degrees (0°), concave lenses (+150°, +450°) to simulate normal vision, moderate myopia, and high myopia scenarios for straight line walking tests. The Qualisys 3D motion capture system and Kistler 3D force platform were employed to collect kinematic and dynamic parameters of the patients, and the differences in related indicators before and after visual intervention were compared.Results Visual intervention affected the step length, walking speed, and joint angles of hemiplegic patients. Especially after acute changes in vision, there is a significant difference in the stride length and ankle joint angle on the patient's affected side.. Under high myopia, step length and step length symmetry were better than under moderate myopia, but at the expense of gait speed. Visual intervention led to asymmetric trends in step length symmetry and joint angle symmetry. There were very significant differences in COP and COP symmetry between normal vision and high myopia.Conclusion Acute changes in vision can significantly affect the gait of hemiplegic patients, especially when there is a notable decrease in walking speed and changes in ankle joint angles with high myopia, and an increase in walking speed with moderate myopia. Additionally, under all conditions of vision change, the symmetry of COP is reduced, indicating a higher risk of falls. This suggests that during the rehabilitation process of hemiplegic patients, reasonable vision assessment and corresponding intervention measures are expected to improve the patient's walking ability and quality of life.
    Effects of motion task and cognitive task interventions on dynamic stability of the body of the elderly when walking downstairs
    FU Qian , YAN Xiao Qin , WANG Jiang Na , MA Gang , SUN Wei
    Adopted date: October 12,2024
    [Abstract](15) [HTML](0) [PDF 0.00 Byte](0)
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    Objective: To investigate how interference from motor and cognitive tasks affects the postural stability of older adults while descending stairs. Methods: The study involved 52 older adults (mean age: 66.8 ± 3.6 years). Using the Vicon infrared motion capture system and Kistler force plate, kinematic and dynamic data were collected simultaneously during stair descent under three conditions: single-task, motor task, and cognitive task. Dynamic stability during stair descent was assessed using the Measure of Stability algorithm. Repeated measures ANOVA was applied to compare differences across conditions. Results: 1) Gait Parameters: Compared to the single-task condition, both step speed (P < 0.001) and step frequency (P < 0.001) were significantly reduced under motor and cognitive task conditions.tep length (P = 0.037) was also significantly reduced under the cognitive task condition compared to the single-task condition. 2) Anterior-Posterior Dynamic Stability: Compared to the single-task condition, centroid velocity (P < 0.001) and extrapolated centroid position (P < 0.001) were significantly increased, while dynamic stability (P < 0.001) was significantly decreased under both motor and cognitive task conditions. In comparison to the cognitive task condition, centroid displacement (P = 0.011) and velocity (P = 0.014) , as well as extrapolated centroid position (P < 0.001) , were significantly greater under the motor task condition. 3) Medial-Lateral Dynamic Stability: Compared to the single-task condition, centroid displacement (P < 0.001) was significantly reduced under both motor and cognitive task conditions. Additionally, the extrapolated centroid position (P = 0.001) was significantly reduced, and dynamic stability (P = 0.038) was significantly increased under the motor task condition compared to the single-task condition. Conclusion: The study found that older adults adjust their gait in response to dual-task interference while descending stairs by "slowing down step speed, reducing step frequency, and shortening step length." This adjustment helps maintain medial-lateral dynamic stability but significantly decreases anterior-posterior dynamic stability, thereby increasing the risk of falls.
    Analysis of bone mineral density and change of muscle tissue in elderly women with hip fracture
    peiwenjiang , xuwenting , mupei , wangyuxuan , maochaoyong , chenjian
    Adopted date: October 10,2024
    [Abstract](8) [HTML](0) [PDF 0.00 Byte](0)
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    Objective To investigate the correlation between the change of muscle tissue and bone density in elderly women with hip fracture. Methods 79 elderly patients with hip fracture were selected as the fracture group and 45 physical examination personnel as the control group. Results Muscle content and fat content of whole body, upper limb and lower limb, trunk fat content, relative index of skeletal muscle mass (SMI) and bone mineral density in the fracture group were significantly lower than those in the control group (P < 0.05). The incidence rate of sarcopenia in fracture population was higher than that in control group (60.76% PS 42.22%). Bone mineral density of femoral neck of the affected side was significantly lower than that of the intact side in women with intertrochanteric fractures (0.490±0.092 VS 0.613±0.099). Logistic analysis found that SMI in elderly women with hip fracture was negatively correlated with age, and positively correlated with body mass index (BMI), femoral neck bone density and systemic bone density. Conclusion The rate of sarcopenia was significantly higher in elderly patients with hip fracture, and SMI was closely related to femoral neck bone density and systemic bone density. Therefore, sarcopenia should be highly emphasized in the prevention and treatment of osteoporotic fracture in elderly people.
    T cell mechanoimmunology research progress
    songfang wu , jizhong Lou
    Adopted date: October 08,2024
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    T cells play essential roles in adaptive immunity, and the specific recognition of antigens by T cell receptors (TCRs) is key in initiating anti-tumor and antiviral immune responses. Recent studies demonstrated that force plays an important regulatory role in T cell immune responses, laying the foundation for the emerging field of mechanoimmunology. In this review, we focus on the mechanisms by which force assists TCRs in distinguishing between specific antigens and non-specific antigens, as well as the critical role force plays in initiating TCR transmembrane signaling and triggering T cell activation. We summarize novel biophysical single-molecule tools and advanced imaging techniques that can deeply reveal the importance of mechanical forces at the molecular and/or cellular level. Here, we tried to provide a deeper understanding of the cutting-edge hotspots in the field of mechanoimunology and suggest potential future directions .