Objective To reconstruct three-dimensional finite element analysis all-ceramic crowm model of the first maxillary molar.Methods After the CT scanning and image processing to the first maxillary molar in vivo,a 3-D geometric model was established by the Imageware software.The mesh model was then built in Abaqus,the finite element analysis software.Result The three dimensional finite element all-ceramic crown models of the first maxillary molar was constructed on the computer,which had 60 160 nodes and 186 328 tetrahedrons elements.Conclusion The finite element model constructed has the advantages of intact structure and precise elements,can simulate the natural condition and facilitate the further biomechanical research.

Objective:To analyze whether there are differences and related influencing factors in liver injury associated with different strains of 2019-nCoV/SARS-CoV-2 infection.Methods:Data of epidemiology, clinical symptoms, laboratory tests, and treatment outcomes of patients with COVID-19 infection confirmed with Alpha and Delta virus strain in Zhejiang Province were retrospectively collected. Statistical analysis was performed using independent samples t-test or Mann-Whitney U test, χ2 test or Fisher's exact test, and logistic regression analysis. Results:A total of 788 and 381 cases with Alpha and Delta virus strain were included. Vaccination ratio was 0% in Alpha and 85.30% in Delta group ( P<0.001), The proportion of patients with fever (80.71% vs. 40.94%, P<0.001) was significantly higher in Alpha than Delta strain group. The proportion of critical ill patients was significantly higher in Delta group (9.90% vs. 1.57%, respectively, P<0.001). The virus negative conversion time was significantly longer in Delta than Alpha group (22 d vs. 11 d, P<0.001), but the incidence of liver injury was significantly higher in Alpha than Delta group (20.05% vs. 13.91%, P=0.011). Univariate analysis showed that Alpha virus strain infection, male sex, body mass index, chronic liver disease, fever, diarrhea, shortness of breath, severe/critical illness, elevated creatine kinase (CK), elevated international normalized ratio (INR) and an elevated neutrophil/lymphocyte ratio was significantly associated with an increased risk of liver injury occurrence, and in patients with pharyngeal pain the risk of liver injury occurrence was significantly reduced. Multivariate analysis showed that shortness of breath [ OR, 2.667 ( CI: 1.389-5.122); P=0.003], increased CK [ OR, 2.544 ( CI: 1.414-4.576); P=0.002] and increased INR [OR, 1.721] ( CI: 1.074-2.758); P=0.024] was significantly associated with an increased risk of liver injury occurrence, and in patients with pharyngeal pain the risk of liver injury occurrence was significantly reduced [ OR, 0.424 ( CI: 0.254-0.709); P=0.001]. Conclusion:Although the virulence of the Delta is stronger than Alpha strain, most patients infected with Delta strain vaccinated against COVID-19 in Zhejiang province had milder clinical symptoms and a lower incidence and degree of liver injury. Notably, the infection risk even remains after vaccination; however, symptoms and the incidence of severe and critical illness can be significantly reduced.

Objective: To analyze the clinical features of respiratory epithelial adenomatoid hamartoma (REAH) in the nasal cavity. Methods: Clinical datas of 23 patients, who were hospitalized in Department of Otorhinolaryngology Head and Neck Surgery, the Affiliated Hospital of Qingdao University, from February 2016 to February 2018 with histopathologically proved REAH in the nasal cavity were reviewed. There were 18 males and 5 females, with the age range from 16 to 71 years old. The most common area, main symptoms, surgical methods and follow-up results were analyzed. Results: The most common area was olfactory cleft (21 cases), and the mainly symptom was nasal congestion (18 cases). All the patients received transnasal endoscopic surgery and had no recurrence during following-up from three months to one year. Conclusions The most common area of REAH in the nasal cavity is the olfactory cleft. Histopathological result is needed to make a definite diagnosis. Complete surgical resection is the main treatment.