Objective: Neck muscle activation plays an important role in maintaining posture and preventing trauma injuries of the head-neck system, levels of which are primarily controlled by the neural system. Thus, the present study aims to establish and validate a neuromuscular head-neck model as well as to investigate the effects of realistic neural reflex control on head-neck behaviors during impact loading. Methods: The neuromuscular head-neck model was first established based on a musculoskeletal model by including neural reflex control of the vestibular system and proprioceptors. Then, a series of human posture control experiments was implemented and used to validate the model concerning both joint kinematics of the cervical spine and neck muscle activations. Finally, frontal impact experiments of varying loading severities were simulated with the newly established model and compared with an original model to investigate the influences of the implanted neural reflex controllers on head-neck kinematic responses. Results: The simulation results using the present neuromuscular model showed good correlations with in-vivo experimental data while the original model even cannot reach a correct balance status. Furthermore, the vestibular reflex is noted to dominate the muscle activation in less severe impact loadings while both vestibular and proprioceptive controllers have a lot of effect in higher impact loading severity cases. Conclusions: In summary, a novel neuromuscular head-model was established and its application demonstrated the significance of the neural reflex control in predicting in vivo head-neck responses and preventing related injury risk due to impact loading.
Head injury is the most common and fatal injury in car-pedestrian accidents. Due to the lack of human test data, real-world accident data is useful for the research on the mechanism and tolerance of head injuries. The objective of the present work is to investigate pedestrian head-brain injuries through real car-pedestrian accidents and evaluate the existed injury criteria. Seven car-to-pedestrian accidents in China were selected from the IVAC (Investigation of Vehicle Accident in Changsha) database. Accident reconstructions using multi-body models were conducted to determine the kinematic parameters associated with the injury and were used to measure head injury criteria. Kinematic parameters were input into a finite element model to run simulations on the head-brain and car interface to determine levels of brain tissue stress, strain, and brain tissue injury criteria. A binary logistic regression model was used to determine the probability of head injury risk associated with AIS3+ injuries (Abbreviated Injury Scale). The results showed that head injury criteria using kinematic parameters can effectively predict injury risk of a pedestrians’ head skull. Regarding brain injuries, physical parameters like coup/countercoup pressure are more effective predictors. The results of this study can be used as the background knowledge for pedestrian friendly car design.
The most commonly used numerical human body models and anthropomorphic test devices (ATDs) in vehicle safety analysis are in the anthropometry of Western European or North American. However, the anthropometric differences between European/American and Chinese population are remarkable and have significant influences on pedestrian kinematics and injury response in vehicle crashes. Therefore, the current study aims to develop and validate a finite element (FE) human body model representing the anthropometry of Chinese 50th% adult male for pedestrian safety analysis and development of Chinese ATDs. Firstly, a human body pedestrian model, named as C-HBM (Chinese Human Body Model), was developed based on the medical image data of a volunteer selected according to both anthropometry and anatomy characteristics of 50th% Chinese adult male. Then, the biofidelity of the C-HBM pedestrian model was validated against cadaver impact test data reported in the literature at the segment and full-body level. Finally, the validated C-HBM pedestrian model was employed to predict Chinese pedestrian injuries in real world vehicle crashes. The results indicate that the C-HBM pedestrian model has a good capability in predicting human body mechanical response in cadaver tests and Chinese pedestrian leg and thorax injuries in real world vehicle crashes. Kinematic analysis shows that the C-HBM pedestrian model has less sliding on the hood surface, shorter movement in the horizontal direction, and higher pelvis displacement in the vertical direction than cadavers and the pedestrian model in the anthropometry of westerner due to anthropometric differences in the lower limbs. This implies that anthropometric differences between different ethnic groups should be considered in applications of numerical human body models and ATDs. The currently developed C-HBM pedestrian model provides a basic tool for vehicle safety design and evaluation in China market, and for development of Chinese ATDs.
This study aimed to evaluate a personalized 3D-printed percutaneous vertebroplasty positioning module and navigation template based on preoperative CT scan data that was designed to treat patients with vertebral compression fractures caused by osteoporosis.A total of 22 patients with vertebral compression fractures admitted to our hospital were included in the study. Positioning was performed with the new 3D-printed positioning module, and the navigation template was used for patients in the experimental group, and the traditional perspective method was used for patients in the control group. The experimental group consisted of 11 patients, 2 males and 9 females, with a mean age of 67.27 ± 11.86 years (range: 48 to 80 years), and the control group consisted of 11 patients, 3 males and 8 females, with a mean age of 74.27 ± 7.24 years (range: 63 to 89 years). The puncture positioning duration, number of intraoperative fluoroscopy sessions, and preoperative and postoperative visual analog scale (VAS) scores were statistically analyzed in both groups.The experimental group had shorter puncture positioning durations and fewer intraoperative fluoroscopy sessions than the control group, and the differences were statistically significant (P < .05). There were no significant differences in age or preoperative or postoperative VAS scores between the two groups (P > .05).The new 3D-printed vertebroplasty positioning module and navigation template shortened the operation time and reduced the number of intraoperative fluoroscopy sessions. It also reduced the difficulty in performing percutaneous vertebroplasty and influenced the learning curve of senior doctors learning this operation to a certain degree.
Abstract Reactive oxygen species (ROS)‐induced oxidative stress in the endoplasmic reticulum (ER) is generally believed to be an important prerequisite for immunogenic cell death (ICD) which can trigger antitumor immune responses for cancer immunotherapy. However, thus far, little is known between the oxidative stress in a certain organelle other than ER and ICD. Herein, polymers for preparing ROS‐responsive nanoparticles (NP‐I‐CA‐TPP) with mitochondrial targeting performance as ICD nanoinducers are designed. It is believed that NP‐I‐CA‐TPP can target mitochondria which are extremely important organelles intimately involved in cellular stress signaling to play an important role in the induction of ICD. NP‐I‐CA‐TPP can amplify cinnamaldehyde (CA)‐induced ROS damage by iodo–thiol click chemistry‐mediated glutathione depletion in cancer cells. Finally, NP‐I‐CA‐TPP is shown to disrupt mitochondrial redox homeostasis, amplify mitochondrial oxidative stress, promote cancer cell apoptosis via inducing ICD, and triggering the body's antitumor immune response for cancer immunotherapy.
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