Objective:To evaluate the bio-mechanics of the cracked molars. Methods: A three dimensional finite element(3D-FEM) model of an upper first molar was constructed by Ansys 8.0 software. The model's cuspal inclination was shaped according to the mean value of the cuspal inclination in the cracked maxillary first molars and the intact ones respectively. The influence of cuspal inclination on the stress distribution was evaluated under different loads:Load of 600 N vertically applied to the occlusal surface of the model, or load of 200 N applied from three directions (vertically, at a 45?angle, horizontally). Results:For the model with the cuspal inclination of the cracked maxillary first molars, its maximum tensile stress, compressive stress and Von Mises stress were higher than those of the control models. The tensile stress and Von Mises stress increased with the increase of force direction and became to the highest under horizontal loads. The tensile stress was mainly distributed at the mediolingual cusp, centre groove and the palatal side of the cervical region. Conclusions: Under equivalent loads, the molar with bigger cuspal inclination suffers more unfavorable stress, which will magnify the occurrence of cracked tooth syndrome (CTS), and horizontal bite force may be a critical factor.

Objective To prepare a novel bioactive and degradable scaffold with mineralized collagenpolyose based composite by biomimetic synthesis for bone tissue engineering and explore the compatibility of osteoblast culturing on the scaffold. Methods Two kinds of polyelectrolyte were assembled on the surface of diatomite particles in order to adsorbe on nano-zirconia through opposite charges. Zeta potential,particle size and size distribution were compared before and after the modification of diatomite; IR was used to analysis molecular structure of functional group changes on the surface of diatomite particles, nano-composite powder morphology was observed by SEM. Results Two kinds of the polyelectrolyte were successfully assembled on the surface of diatomite powders. Particle size and size distribution were significantly reduced, d (0.5) reduce from 16.421 μm to 0.420 μm. SEM showed the dispersion of the modified diatomite was improved and had a good adsorption with nano-zirconia. Conclusion Layer-by-layer technique could enhance the dispersion of diatomite-based dental ceramic powders as well as a good adsorption of nano-composite ceramic powder.

Objective:To study the effect of PAD (presentation-assimilation-discussion) class applied in the standardized residency training of dermatovenereology on improving residents' practical operation ability.Methods:A total of 120 residents taking the standardized residency training of dermatovenereology in the Affiliated Hospital of North Sichuan Medical College from November 2018 to December 2020 were selected as the research objects and divided into two groups according to the time order of admission, among which, 60 residents enrolled from November 2018 to November 2019 were selected as the control group, and 60 residents enrolled from December 2019 to December 2020 were selected as the experimental group. The control group adopted the traditional standardized residency training mode, and the experimental group adopted the teaching mode of PAD class. SPSS 22.0 statistical software was used for data analysis. The results of theoretical knowledge assessment and skill operation assessment were compared between the two groups by t test, the evaluation of teaching effect was compared between the two groups by chi-square test, and the satisfaction of teaching was compared between the two groups by rank sum test. Results:The theoretical knowledge [(45.38±4.14) points], skill operation [(42.35±4.32) points] and total score [(88.74± 7.69) points] of the experimental group were higher than those of the control group [(39.62 ± 4.15) points, (36.25±4.27) points, (77.96±7.52) points, respectively], with statistical significance ( P<0.05). The evaluation of teaching effect in the experimental group showed that 49 residents (81.67%) believed that their learning interest had been stimulated; 51(85.00%) improved their self-learning ability; 47(78.33%)improved their ability of analyzing and solving problems; 50(83.33%) improved their doctor-patient communication ability; 49(81.67%) improved their clinical thinking ability; 52(86.67%) improved their teamwork ability; and 50(83.33%) improved their literature retrieval ability. The results of satisfaction showed that the experimental group was significantly higher than the control group in sense of responsibility, teaching methods, teaching contents and self-evaluation. Conclusion:The application of PAD class in the standardized residency training of dermatovenereology plays a positive role in mobilizing the learning enthusiasm of residents and cultivating their independent learning ability, and can significantly improve the practical operation and theoretical awareness of residents.

OBJECTlVE To establish Tg(-6.3CYP3A65∶EGFP) transgenic zebrafish for quick, intuitive detection of heavy metals ( copper, cadmium and zinc) , dioxin-like PCBs ( PCB126) and other environmental pollutants. METHODS Tol2 transposon system was used to generate transgenic zebrafish lines Tg(-6.3CYP3A65∶EGFP) in which CYP3A65 promoter regualated labeled fluorescence. The effect of heavy mentals ( copper, cadmium and zinc ) and PCB126 on the relative amounts of CYP3A65 gene expression was determined by observing the change in fluorescence intensity. RESULTS The relative gene expression of CYP3A65 was significantly increased after 96 h exposure to copper 0.1 and 0.2μmol·L-1 , cadmium 0.35 and 0.7μmol·L-1 , zinc 1.5 and 3μmol·L-1 , and PCB126 2-32μmol·L-1 , respectively ( P<0.01) , but decreased after 96 h exposure to copper 0. 9 μmol·L-1 , cadmium 2. 7 and 5.4 μmol·L-1 , and zinc 24μmol·L-1 , respectively( P<0.01) . CYP3A65 gene expression was significantly increased after 168 h exposure to copper 0.1 and 0.2 μmol·L-1 , cadmium 0.35 and 0.7 μmol·L-1 , zinc 1.5 and 3 μmol·L-1, and PCB126 2-32 μmol·L-1, respectively(P<0.01), but decreased after 168 h exposure to copper 0.9 μmol·L-1, cadmium 2.7 and 5.4 μmol·L-1, and zinc 12 and 24 μmol·L-1( P<0.05) , in a concentration-dependent manner. CONCLUSlON The results suggest that zebrafish CYP3A65 gene expression and the CYP3A65 labeled fluorescence lines can be another candidate biomarker for detecting environmental pollutants.

Immune evasion has made ovarian cancer notorious for its refractory features, making the development of immunotherapy highly appealing to ovarian cancer treatment. The immune-stimulating cytokine IL-12 exhibits excellent antitumor activities. However, IL-12 can induce IFN-γ release and subsequently upregulate PDL-1 expression on tumor cells. Therefore, the tumor-targeting folate-modified delivery system F-DPC is constructed for concurrent delivery of IL-12 encoding gene and small molecular PDL-1 inhibitor (iPDL-1) to reduce immune escape and boost anti-tumor immunity. The physicochemical characteristics, gene transfection efficiency of the F-DPC nanoparticles in ovarian cancer cells are analyzed. The immune-modulation effects of combination therapy on different immune cells are also studied. Results show that compared with non-folate-modified vector, folate-modified F-DPC can improve the targeting of ovarian cancer and enhance the transfection efficiency of pIL-12. The underlying anti-tumor mechanisms include the regulation of T cells proliferation and activation, NK activation, macrophage polarization and DC maturation. The F-DPC/pIL-12/iPDL-1 complexes have shown outstanding antitumor effects and low toxicity in peritoneal model of ovarian cancer in mice. Taken together, our work provides new insights into ovarian cancer immunotherapy. Novel F-DPC/pIL-12/iPDL-1 complexes are revealed to exert prominent anti-tumor effect by modulating tumor immune microenvironment and preventing immune escape and might be a promising treatment option for ovarian cancer treatment.