Effects of whole-body vibration at different periods on lumbar vertebrae in female rats.

The current study aimed to investigate the effects of whole-body vibration (WBV) before and after ovariectomy on lumbar vertebrae, and to observe whether the positive effects of WBV before and after ovariectomy on lumbar vertebrae in rats could be maintained after vibration stopped. Three-month-old female rats were divided into four groups (n = 45/group): control (CON), ovariectomy (OVA), WBV before ovariectomy (WBV-BO), and WBV after ovariectomy (WBV-AO) groups. For 1-8 weeks, WBV-BO group was subjected to vertical WBV. At the 9th week, the rats in WBV-BO, WBV-AO, and OVA groups were ovariectomized. During 11-18 weeks, WBV-AO group was subjected to vibration. For 19-26 weeks, no intervention was done for rats. The lumbar vertebrae were examined by Micro-CT, compressive test, creep test, and microindentation test. At the 8th week, the displacement of the L1-L2 annulus fibrosus in WBV-BO group was 18% smaller compared with CON group (p<0.05). At the 18th week, the elastic modulus of the L5 vertebral body in WBV-BO and WBV-AO groups was 53% and 57% higher than that in CON group, respectively (p<0.05); the displacement of the L1-L2 annulus fibrosus in WBV-BO group was 25% smaller than those in the other groups (p<0.05). At the 26th week, there was no significant difference in the displacement of the L1-L2 annulus fibrosus between WBV-BO group and other groups (p>0.05); the elastic modulus of the L5 vertebral body had no significant difference between WBV-AO group and CON group (p>0.05). Our results demonstrated that WBV before ovariectomy effectively prevented disc degeneration with significant effects up to 8 weeks after ovariectomy. The vertebral mechanical properties could be significantly improved by WBV after ovariectomy, but the residual effect did not maintain after WBV stopped.

[Design of new gradient scaffolds based on triply periodic minimal surfaces and study on its mechanical, permeability and tissue differentiation characteristics].

In order to establish a bone scaffold with good biological properties, two kinds of new gradient triply periodic minimal surfaces (TPMS) scaffolds, i.e., two-way linear gradient G scaffolds (L-G) and D, G fusion scaffold (N-G) were designed based on the gyroid (G) and diamond (D)-type TPMS in this study. The structural mechanical parameters of the two kinds of scaffolds were obtained through the compressive simulation. The flow property parameters were also obtained through the computational fluid dynamics (CFD) simulation in this study, and the permeability of the two kinds of scaffolds were calculated by Darcy's law. The tissue differentiation areas of the two kinds of scaffolds were calculated based on the tissue differentiation theory. The results show that L-G scaffold has a better mechanical property than the N-G scaffold. However, N-G scaffold is better than the L-G scaffold in biological properties such as permeability and cartilage differentiation areas. The modeling processes of L-G and N-G scaffolds provide a new insight for the design of bone scaffold. The simulation in this study can also give reference for the prediction of osseointegration after the implantation of scaffold in the human body.

[Study of building up a comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy].

OBJECTIVE: To build up a simple and effective comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy. METHOD: One hundred and twenty cases of laryngeal tubor were selected. Using Logistic regression method to analyse relative factors, including weight, height, BMI, neck girth, neck upward degree, upper-lower incisor teeth distance, thyroid-mentum distance, thyroid-sternum distance, Mallampati test, Yamamoto test and Upper lip bite test. Build data-base to construct a comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy. RESULT: The relative factors of difficult laryngeal exposure were BMI, neck girth, upper-lower incisor teeth distance, neck upward degree, thyroid-mentum distance, Mallampati test and Yamamoto test (P < 0.05). To build up a comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy. The predicting standards included the seven relative factors, each factor has 1 score, 2 score, 3 score. Higher score means more risk. Eight score was designed as minimum, under the premise,the sensibility, misdiagnosis rate, missed misdiagnosis rate, specificity of the experiment were 95.5%, 5.3%, 4.5%, 94.7%. CONCLUSION: The comprehesive system is an effective method for predicting difficult intubation. It can help to identify difficult cases according to the results of this predicting system.