Objective On the basis of explicit dynamics calculation theory, a numerical model for calculating active and passive properties of muscles with high strain rate was proposed. Methods In the process of calculating the motion equation of muscle element with high strain rate, Hill’s three-factor muscle model with high strain rate was introduced into the noda force formula to modify the node force in each time step. Results As Hill’s three-factor muscle model was introduced in numerical calculation, the muscle element had the passive characteristics of the general structural constitutive model and its proprietary active characteristics. Conclusions The research findings will contribute to numerical calculation for dynamic response and damage of muscles with high strain rate.

OBJECTIVETo investigate the clinical value of high-field-strength intraoperative magnetic resonance imaging (iMRI) combined with optic radiation neuro-navigation for the resection of temporal lobe low-grade gliomas.

METHODSFrom April 2009 to September 2013, 65 patients with temporal lobe low-grade gliomas (WHO grade II) involving optic radiation were operated with iMRI and functional neuro-navigation. Diffusion tensor imaging (DTI) based fiber tracking was used to delineate optic radiation. The reconstructed optic radiations were integrated into a navigation system, in order to achieve intraoperative microscopic-based functional neuro-navigation. iMRI was used to update the images for both optic radiations and residual tumors. Volumetric analyses were performed using 3D Slicer for pre- and intra-operative tumor volumes in all cases. All patients were evaluated for visual field deficits preoperatively and postoperatively. The Student t test was used to evaluate the average rate of extent of resection between groups. Spearman rank correlation analysis was used to assess correlations between predictors and epilepsy prognosis.

RESULTSPreoperative tumor volumes were (78±40) cm3. In 29 cases, iMRI scan detected residual tumor that could be further resected, and extent of resection were increased from 76.2% to 92.7% (t=7.314, P<0.01). In 19 cases (29.2%), gross total resection was accomplished, and iMRI contributed directly to 8 of these cases. Postsurgical follow-up period varied from 13 months to 59 months, mean (33±13) months. Tumor progression were observed in 3 patients, newly developed or deteriorated visual field defects occurred in 4 patients (6.2%). For patients with pre-operative seizures, Engel Class I were achieved for 89.7% of them. Spearman rank correlation analysis revealed that seizure outcome (Engel Class) was related to increased excision of ratio (r=-0.452, P=0.004, 95% CI: -0.636--0.261) and larger tumors (r=0.391, P=0.014, 95% CI: 0.178-0.484).

CONCLUSIONSWith iMRI and functional neuro-navigation, the optic radiation can be accurately located, while extent of resection can be evaluated intra-operatively. This technique is safe and helpful for preservation of visual field for the resection of temporal lobe low-grade gliomas involving optic radiation.

Brain Neoplasms ; pathology ; surgery ; Glioma ; pathology ; surgery ; Humans ; Magnetic Resonance Imaging ; Neuronavigation ; Temporal Lobe ; surgery

ObjectiveTo assess the level of internal exposure to PCP in a community population in Shanghai， to investigate the factors affecting the level of PCP， and to analyze the correlation between the exposure and thyroid hormone levels. MethodsA total of 464 residents of a community in Shanghai were selected as the study subjects. A questionnaire survey was conducted to obtain the demographic information， dietary situation， lifestyle and behavioral habits， and disease history of the individuals， and blood samples were collected. Gas chromatography-electron trap was applied to determine the PCP levels in serum. Multicategorical logistic regression analysis was used to analyze the possible influencing factors of PCP exposure in humans. Thyroid hormone levels were used as the dependent variable and serum PCP as the independent variable. Multiple linear regression analysis was used to assess the association between PCP and thyroid hormones in the community population after controlling the confounding factors such as age， gender， literacy， annual personal income， and chronic diseases. ResultsThe detection rate of serum PCP in 464 subjects was 90.3%， and the median serum PCP level was 0.43 μg·L^-1. The differences in PCP levels among different age groups were statistically significant. There were no significant differences in PCP levels among different gender and BMI groups. The study of PCP exposure factors showed that age， frequency of using plastic products， consumption of freshwater fish， type of occupation， annual income， and consumption of tea or coffee were the potential influencing factors for PCP exposure. Among them， age， frequency of using plastic products， consumption of tea or coffee， and consumption of freshwater fish were positively associated with PCP levels， and annual personal income was negatively associated with it. The results of multiple linear regression analysis showed that among men， PCP levels were positively correlated with TSH （b=0.105， 95%CI：0.017‒0.313） and negatively correlated with FT4 （b=-0.026， 95%CI：-0.057‒0.004）， and among women， PCP levels were positively correlated with TSH （b=0.092， 95%CI：-0.211‒0.904） and FT3 （b=0.017， 95%CI：-0.058‒0.230） and negatively correlated with FT4 （b=-0.013， 95%CI：-0.011‒0.037）. ConclusionSerum PCP detection is common among community residents in Shanghai. Different demographic characteristics or behavioral habits may increase or decrease PCP exposure. PCP exposure then affects human thyroid hormone levels.