Spatial relationships among offender, knife, and victim during slashing attacks: implications for crime scene reconstruction.

BACKGROUND: The offender-victim spatial relationship is crucial in reconstructing a crime scene. The study aims to evaluate the spatial relationship of performing slashing attacks on a dummy using a Chinese kitchen knife, and thus to establish a scientific basis for crime scene reconstruction. METHODS: Twenty-four participants (12 males and 12 females) slashed a dummy's neck or chest using a kitchen knife, and the kinematic data were obtained using a three-dimensional motion capture system. The spatial relationships among offender, knife, and victim during slashing attacks were analyzed. RESULTS: Slashing distance and occupancy area are significantly influenced by gender (all P < 0.05), with males having higher values than females. Body parts significantly influence bevel angle, offender and victim azimuth angles, slashing distance, relative slashing distance, and occupancy area (all P < 0.01), with slashing the chest resulting in larger values than slashing the neck. CONCLUSION: Gender and body position significantly influence the spatial relationships of slashing action. Our data indicate that males stand farther away and occupy a larger area during slashing attacks. When the chest is slashed, the wound orientation is more diagonal, the offender's standing position and slashing distance are farther, and the occupancy area is larger compared to the neck. The findings could help identify the spatial relationships among offender, knife, and victim, providing a scientific basis for criminal investigations and court trials.

Voltage-gated sodium channels in cancer and their specific inhibitors.

Voltage-gated sodium channels (VGSCs) participate in generating and spreading action potentials in electrically excited cells such as neurons and muscle fibers. Abnormal expression of VGSCs has been observed in various types of tumors, while they are either not expressed or expressed at a low level in the matching normal tissue. Hence, this abnormal expression suggests that VGSCs confer some advantage or viability on tumor cells, making them a valuable indicator for identifying tumor cells. In addition, overexpression of VGSCs increased the ability of cancer cells to metastasize and invade, as well as correlated with the metastatic behavior of different cancers. Therefore, blocking VGSCs presents a new strategy for the treatment of cancers. A portion of this review summarizes the structure and function of VGSCs and also describes the correlation between VGSCs and cancers. Most importantly, we provide an overview of current research on various subtype-selective VGSC inhibitors and updates on ongoing clinical studies.

Predicting vertical ground reaction force in rearfoot running: A wavelet neural network model and factor loading.

This study proposed a simple method for selecting input variables by factor loading and inputting these variables into a wavelet neural network (WNN) model to predict vertical ground reaction force (vGRF). The kinematic data and vGRF of 9 rearfoot strikers at 12, 14, and 16 km/h were collected using a motion capture system and an instrumented treadmill. The input variables were screened by factor loading and utilized to predict vGRF with the WNN. Nine kinematic variables were selected, corresponding to nine principal components, mainly focusing on the knee and ankle joints. The prediction results of vGRF were effective and accurate at different speeds, namely, the coefficient of multiple correlation (CMC) > 0.98 (0.984-0.988), the normalized root means square error (NRMSE) < 15% (9.34-11.51%). The NRMSEs of impact force (8.18-10.01%), active force (4.92-7.42%), and peak time (7.16-12.52%) were less than 15%. There was a small number (peak, 4.12-6.18%; time, 4.71-6.76%) exceeding the 95% confidence interval (CI) using the Bland-Altman method. The knee joint was the optimal location for estimating vGRF, followed by the ankle. There were high accuracy and agreement for predicting vGRF with the peak and peak time at 12, 14, and 16 km/h. Therefore, factor loading could be a valid method to screen kinematic variables in artificial neural networks.

Gain-of-function mutations in the catalytic domain of DOT1L promote lung cancer malignant phenotypes via the MAPK/ERK signaling pathway.

Lung cancer is a lethal malignancy lacking effective therapies. Emerging evidence suggests that epigenetic enzyme mutations are closely related to the malignant phenotype of lung cancer. Here, we identified a series of gain-of-function mutations in the histone methyltransferase DOT1L. The strongest of them is R231Q, located in the catalytic DOT domain. R231Q can enhance the substrate binding ability of DOT1L. Moreover, R231Q promotes cell growth and drug resistance of lung cancer cells in vitro and in vivo. Mechanistic studies also revealed that the R231Q mutant specifically activates the MAPK/ERK signaling pathway by enriching H3K79me2 on the RAF1 promoter and epigenetically regulating the expression of downstream targets. The combination of a DOT1L inhibitor (SGC0946) and a MAPK/ERK axis inhibitor (binimetinib) can effectively reverse the R231Q-induced phenomena. Our results reveal gain-of-function mutations in an epigenetic enzyme and provide promising insights for the precise treatment of lung cancer patients.

Stride length mediates the correlation between movement coordination and sprint velocity.

In this study, we aimed to explore the correlation between movement coordination and sprint velocity and the mediating effects of stride length and frequency on this correlation. Thirty-two male college students (16 athletes and 16 non-athletes) participated in this study. Movement coordination was calculated using a vector coding method for intralimb (hip - knee, knee - ankle) and interlimb (hip - hip, knee - knee, ankle - ankle). There was a significant effect of group on hip - knee, hip - hip and ankle - ankle coupling angle during braking phase and knee - knee coupling angle during the propulsive phase. In all participants, the hip - hip coupling angle during the braking phase was positively correlated with sprint velocity, and the ankle - ankle coupling angle during the braking phase was negatively correlated with sprint velocity. Stride length mediated the relationship between hip - hip coupling angle and sprint velocity. In conclusion, the anti-phase of the hip - hip coupling angle and the swing phase of the ankle - ankle coupling angle may contribute to sprint velocity. Moreover, the correlation between hip - hip coupling angle and sprint velocity was related to stride length rather than stride frequency.

Biomechanical characteristics of slashing attack on different body parts of a dummy using a kitchen knife.

BACKGROUND: Slashing attack is one of the most common ways of committing a homicide. The purpose of this study was to evaluate the biomechanical characteristics of slashing different body parts of a dummy by young males and females using a Chinese kitchen knife and thus provide scientific evidence for criminal investigations and court trials. METHODS: A total of 12 male and 12 female college students participated in this study. Biomechanical parameters, including joint velocity, slashing velocity, slashing force, energy, and impulse, were evaluated when slashing the chest and the neck of a dummy using a Chinese kitchen knife. RESULTS: When slashing the neck or the chest of a dummy, male participants showed higher elbow and wrist velocities (21.2% and 28.5%, respectively) as well as higher knife velocity (33.6%), slashing velocity (25.3%), slashing force (23.3%), and energy (57.6%) compared to female participants (all p < 0.05). When slashing the chest, participants showed higher shoulder, elbow, and wrist velocities (31.9%, 12.7%, and 12.6%) as well as knife velocity (3.8%), slashing velocity (7.3%), and energy (23.2%) compared to slashing the neck (all p < 0.05), regardless of gender. CONCLUSION: Both gender and slashing position have great impact on biomechanical characteristics of the slashing movement. Our data indicate that when slashing using a Chinese kitchen knife, males may induce severer wounds than females, and slashing different body parts may generate different slashing velocity or energy. Compared to slashing position, gender may have greater influence on the biomechanical characteristics. Findings from this study may expand our knowledge about knife slashing attacks by Chinese kitchen knives as well as other knives with comparative heavy blades.

Gender-Specific Effects of 8-Week Multi-Modal Strength and Flexibility Training on Hamstring Flexibility and Strength.

The purpose of this study was to investigate the effects of multi-modal strength training or flexibility training on hamstring flexibility and strength in young males and females. A total of 20 male and 20 female college students (aged 18-24 years) participated in this study and were randomly assigned to either a multi-modal flexibility intervention group or strength intervention group. Passive straight leg raise and isokinetic strength test were performed before and after the intervention to determine flexibility and strength of the participants. Multivariate repeated-measure ANOVA was used to determine the effect of training group and gender on hamstring strength and flexibility. Both male and female participants in the strength intervention group significantly increased peak torque, relative peak torque, and flexibility (all p ≤ 0.029). Both male and female participants in the flexibility intervention group significantly increased flexibility (both p ≤ 0.001). Female participants in the flexibility intervention group significantly increased peak torque and relative peak torque (both p ≤ 0.023). However, no change was seen in peak torque and relative peak torque of male participants in the flexibility intervention group (p ≥ 0.676). An 8-week strength training program involving various training components can increase flexibility in both males and females, although the flexibility of male participants only increased slightly. While hamstring flexibility training protocol consisted of different types of stretching improved both flexibility and strength in female participants, male participants increased only flexibility but not strength, indicating such effects were gender-specific. For subjects with relatively low strength (e.g., older adults, sedentary women, postoperative rehabilitation population, etc.), strength training alone or flexibility training alone may increase both strength and flexibility.

Effects of integrative neuromuscular training intervention on physical performance in elite female table tennis players: A randomized controlled trial.

OBJECTIVES: To investigate the effects of integrative neuromuscular training (INT) on physical performance in elite female table tennis players. METHODS: Twenty-four Chinese elite female table tennis players were randomized into either INT (n = 12) group or control group (CON; n = 12). INT group performed four INT sessions every week for 8 weeks, while CON group performed traditional physical fitness training. One repetition maximal (1RM), vertical jump, Y balance test and 30-meter sprinting performance were tested before and after intervention. RESULTS: No between groups differences were detected for any tests before intervention. Significant group by time (before or after intervention) interaction effects were observed in 1RM, vertical jump, bilateral lower limb reaching distance at posteromedial and posterolateral directions, and right leg at the anterior direction for the Y balance test (all p < 0.05), but not for the left leg at the anterior direction or the 30-meter sprinting performance (both p > 0.05). Post-hoc analysis for measurements with significant interactions revealed that all significant changes were at the ING group (all p < 0.05), while no changes for the CON group were observed (all p > 0.05). CONCLUSION: Eight weeks INT significantly improved strength, power and balance in Chinese elite female table tennis players. Adopting INT in table tennis players may improve their physical performance and lead to better sports performance.

Characteristics of the Distance and Space Required for Knife Slashing Using a Motion Capture System.

OBJECTIVES: To investigate the relationship between the perpetrator's sex, victim's position and slashing location as well as anthropometric parameters on distance and space required for slashing, to provide the theoretical basis for the judgment of whether the crime scene was consistent with the criminal activity space. METHODS: The kinematics data of 12 male and 12 female subjects slashing the neck of standing and supine mannequins as well as the chest of the standing mannequins with a kitchen knife were obtained by using a 3D motion capture system. The relationship between the perpetrator's sex-victim's position, the perpetrator's sex-slashing location, and anthropometric parameters and the distance and space required for the slashing were analyzed by two-factor repeated measures ANOVA and Pearson correlation analysis respectively. RESULTS: Compared with slashing the neck of supine mannequins, the distance (L) and normalized L (l) of slashing the neck of standing mannequins were greater, while vertical distance (LVR) and normalized LVR (lVR) of the knife side were smaller. Compared with slashing the neck of standing mannequins, the L and l slashing the chest of standing mannequins were greater, while LVR and lVR were smaller. Horizontal distance (LHR) and normalized LHR (lHR) of the knife side in males were greater than that in females. Height and arm length were positively correlated with L, LHR, and LVR when striking the standing mannequins. CONCLUSIONS: When slashing the neck of supine or standing victims, the slashing distance is shorter and the slashing height is greater. Furthermore, the distance and space required for slashing are correlate with anthropometric parameters.

Effects of motor skill level and speed on movement variability during running.

Variability in movement is an informative biological feature. This study aimed to examine the effects of motor skill level and running speed on movement variability. Twenty-nine male college students (fourteen athletes and fifteen non-athletes) participated in this study. All participants performed three motor tasks: 3 m/s running, 5 m/s running, and sprint running. Lower-limb kinematic data were acquired using a 16-camera infrared motion capture system. Lower-limb coordination during the stance phase was quantified using a continuous relative phase (CRP) method for interlimb (hip-hip, knee-knee, ankle-ankle) and intralimb (hip-knee, knee-ankle). The variabilities of stride length, stride cadence, joint angles, intralimb CRP, and interlimb CRP were calculated as standard deviations of each measurement. The results revealed that there were significant interaction effects between motor skill level and speed on movement variability for stride length (p = 0.047), ankle angle during propulsive phase (p = 0.001), knee-ankle CRP during propulsive phase (p = 0.007) and knee-knee CRP during propulsive phase (p = 0.009). Athletes showed greater angle variability, coordination variability and lower stride length variability during sprinting (all p < 0.05). In contrast, no between groups variability difference was observed when jogging at fixed lower speeds (all p > 0.05). Movement variability was greater for sprinting compared to jogging. Skill level was found to differentially affect the role of coordination variability in sprint performance. For athletes, hip-knee deviation phase and hip-hip deviation phase during braking phase were negatively correlated with sprinting speed (r = -0.563 and -0.642, respectively; both p < 0.05). For non-athletes, hip-knee deviation phase was positively correlated with sprinting speed (r = 0.581, p = 0.023). In conclusion, stride length become more stable, joint angle and coordination become more variable with long-term training. Results of this study also suggest that the relationship between coordination variability and performance is complicated and may depend on motor skill level. More longitudinal studies are needed to definitively determine the relationship between movement variability and performance.

Effects of flexibility and strength training on peak hamstring musculotendinous strains during sprinting.

BACKGROUND: Hamstring injury is one of the most common injuries in sports involving sprinting. Hamstring flexibility and strength are often considered to be modifiable risk factors in hamstring injury. Understanding the effects of hamstring flexibility or strength training on the biomechanics of the hamstring muscles during sprinting could assist in improving prevention strategies and rehabilitation related to these injuries. The purpose of this study was to determine the effects of altering hamstring flexibility or strength on peak hamstring musculotendinous strain during sprinting. METHODS: A total of 20 male college students (aged 18-24 years) participated and were randomly assigned to either a flexibility intervention group or a strength intervention group. Each participant executed exercise training 3 times a week for 8 weeks. Flexibility, sprinting, and isokinetic strength testing were performed before and after the 2 interventions. Paired t tests were performed to determine hamstring flexibility or strength intervention effects on optimal hamstring musculotendinous lengths and peak hamstring musculotendinous strains during sprinting. RESULTS: Participants in the flexibility intervention group significantly increased the optimal musculotendinous lengths of the semimembranosus and biceps long head (p ≤ 0.026) and decreased peak musculotendinous strains in all 3 bi-articulate hamstring muscles (p ≤ 0.004). Participants in the strength-intervention group significantly increased the optimal musculotendinous lengths of all 3 hamstring muscles (p ≤ 0.041) and significantly decreased their peak musculotendinous strain during sprinting (p ≤ 0.017). CONCLUSION: Increasing hamstring flexibility or strength through exercise training may assist in reducing the risk of hamstring injury during sprinting for recreational male athletes.

Effects of flexibility and strength interventions on optimal lengths of hamstring muscle-tendon units.

OBJECTIVES: The aim of the present study was to determine the effects of altering both hamstring flexibility and strength on hamstring optimal lengths. DESIGN: Controlled laboratory study. METHODS: A total of 20 male and 20 female college students (aged 18-24 years) participated in this study and were randomly assigned to either a flexibility intervention group or a strength intervention group. Passive straight leg raise and isokinetic strength test were performed before and after interventions. Paired T-tests were performed to determine hamstring flexibility or strength intervention effects on hamstring optimal lengths. RESULTS: Male participants in the flexibility intervention group significantly increased range of hip joint flexion (P=0.001) and optimal lengths of semimembranosus and biceps long head (P≤0.026). Male participants in the strength intervention group significantly increased hamstring strength (P=0.001), the range of hip joint flexion (P=0.037), and optimal lengths of all three bi-articulated hamstring muscles (P≤0.041). However, female participants did not significantly increase their hamstring optimal lengths in either intervention groups (P≥0.097) although both groups significantly increased the range of hip joint flexion and strength (P≤0.009). CONCLUSION: Hamstring optimal lengths can be modified through flexibility intervention as well as strength intervention for male participants, but not for female participants in this study. Hamstring optimal lengths should be considered as hamstring flexibility measures in future prospective studies to identify potentially modifiable risk factors for hamstring injury.