Objective To analyze the contact failure of monolithic lithium disilicate CAD/CAM crowns by experiment and numerical simulation, and explore the influences of adhesives aging in water on load-bearing capacity of the crowns. Methods The specimens of sectioned monolithic lithium disilicate crowns were designed and manufactured, and evenly divided into two groups and stored in the air and in the distilled water for 30 days, respectively. The specimens were then subjected to monotonic contact loads to compare and analyze their load-bearing capacity. The fractured surfaces and adhesive interfaces of the specimens were observed by scanning electronic microscope. Meanwhile, the stress distribution on the crowns was calculated by numerical simulation to analyze the adhesives aging influence on load-bearing capacity of the crowns. Results The fracture loads on crowns stored in the air and in the water were (561.51 ± 65.66) N and (398.09 ± 90.20) N, respectively, indicating a significant difference. The tensile stress increased considerably at lower surface of the ceramic crown due to the reduction of adhesive strength at the interface of ceramic crown and substrate, which could increase the propensity of contact failure. Conclusions The adhesives aging in water reduces the bonding strength, and accordingly changes the tensile stress distributions, which can lower the load bearing capacity of the lithium disilicate crowns. The research finding provides references for the design and manufacturing of all-ceramic CAD/CAM restored crowns in clinic.

The application of ArcGIS and Maxent modelto analyze the ecological suitability of Gardenia jasminoides.Taking 85 batches of Gardenia as the basis of analysis, the selection of ecological factors for the growth of Gardenia. The results showed that the average precipitation in April, the average precipitation in November and the average precipitation in August were the most important factors affecting the growth of Gardenia. The relative concentration of Gardenia suitable growth region,north to the south of Shaanxi province, south of Henan, central Anhui, south to the north of Hainan province, west to central Sichuan province, east of Zhejiang coastal area, northeast of Taiwan.

OBJECTIVES: To investigate the clinical treatment outcomes and the changes of the outcomes over time in extremely preterm twins in Guangdong Province, China. METHODS: A retrospective analysis was performed for 269 pairs of extremely preterm twins with a gestational age of <28 weeks who were admitted to the department of neonatology in 26 grade A tertiary hospitals in Guangdong Province from January 2008 to December 2017. According to the admission time, they were divided into two groups: 2008-2012 and 2013-2017. Besides, each pair of twins was divided into the heavier infant and the lighter infant subgroups according to birth weight. The perinatal data of mothers and hospitalization data of neonates were collected. The survival rate of twins and the incidence rate of complications were compared between the 2008-2012 and 2013-2017 groups. RESULTS: Compared with the 2008-2012 group, the 2013-2017 group (both the heavier infant and lighter infant subgroups) had lower incidence rates of severe asphyxia and smaller head circumference at birth (P<0.05). The mortality rates of both of the twins, the heavier infant of the twins, and the lighter infant of the twins were lower in the 2013-2017 group compared with the 2008-2012 group (P<0.05). Compared with the 2008-2012 group, the 2013-2017 group (both the heavier infant and lighter infant subgroups) had lower incidence rates of pulmonary hemorrhage, patent ductus arteriosus (PDA), periventricular-intraventricular hemorrhage (P-IVH), and neonatal respiratory distress syndrome (NRDS) and a higher incidence rate of bronchopulmonary dysplasia (P<0.05). CONCLUSIONS There is a significant increase in the survival rate over time in extremely preterm twins with a gestational age of <28 weeks in the 26 grade A tertiary hospitals in Guangdong Province. The incidences of severe asphyxia, pulmonary hemorrhage, PDA, P-IVH, and NRDS decrease in both the heavier and lighter infants of the twins, but the incidence of bronchopulmonary dysplasia increases. With the improvement of diagnosis and treatment, the multidisciplinary collaboration between different fields of fetal medicine including prenatal diagnosis, obstetrics, and neonatology is needed in the future to jointly develop management strategies for twin pregnancy.
Bronchopulmonary Dysplasia/epidemiology* ; Female ; Gestational Age ; Humans ; Infant ; Infant, Extremely Premature ; Infant, Newborn ; Pregnancy ; Respiratory Distress Syndrome, Newborn/epidemiology* ; Retrospective Studies ; Treatment Outcome

Objective: To investigate the effect and mechanism of Xiaoyaosan on lipopolysaccharide(LPS)-induced nerve injury. Method: The 56 rats were randomly divided into control group, sham group, model group, amitriptyline group (10 mg·kg^-1), fluoxetine group (10 mg·kg^-1), Xiaoyaosan group high and low-dose (30,15 g·kg^-1).The nerve injury model rat were established by LPS injection into lateral ventride, rats were administrated for 14 days by gavage. The levels of brain-derived neurotrophic factor (BDNF) and β-nerve growth factor (β-NGF) in serum were detected by enzyme linked immunosorbent assay(ELISA), and the expressions of BDNF, nerve growth factor (NGF), tropomyosin receptor kinase B (TrkB), tropomyosin receptor kinase A (TrkA), cAMP response element-binding protein (CREB) mRNA in hippocampus and cortex were detected by Real-time PCR.Protoin expression of BDNF, TrkB, CREB, p-CREB, postsynaptic density protein 95 (PSD95), synaptophysin (SYP) in hippocampus and cortex were detected by Western blot. Result: Compared with control group, LPS decreased the level of BDNF and β-NGF in serum(P<0.01),reduced the expression of BDNF, NGF, TrkB,TrkA, CREB mRNA and the expression of BDNF, TrkB, CREB, Phospho-CREB (p-CREB), PSD95, SYP in hippocampus and cortex(P<0.05,P<0.01). Compared with model group, levels of BDNF and β-NGF in serum in Xiaoyaosan high and low-dose group were increased significantly (P<0.05,P<0.01),and expressions of BDNF, NGF, TrkB,TrkA, CREB, PSD95, SYP in hippocampus and cortex were increased significantly (P<0.05, P<0.01). Conclusion: Xiaoyaosan has a certain antagonistic effect on LPS inducednerve injury, which suggests that the effect is related to activate BDNF/NGF-TrkB/TrkA-CREB pathway and upregulated the expression of synaptic protein.