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Purpose: To investigate the correlation between the occlusal canting and the bilateral temporomandibular joint (TMJ) space in adult and juvenile mandibular deviation patients and study the mutual influence between the occlusal canting and mandibular position, in order to provide references for clinical treatment., Methods: CBCT data of mandibular deviation patients（20 adults，20 juveniles）were selected. Inivo5 Dental Anatomage software was used to reconstruct the structures. The occlusal cant and vertical height of the bilateral maxillary from canines to first molars were measured, and the vertical heights difference between the same teeth on both sides was calculated. The anterior, superior and posterior space of temporomandibular joint were measured respectively in both groups. Pearson correlation analysis between the occlusal canting and bilateral condylar space was carried out by using SPSS 17.0 software package., Results: In the juvenile group, negative correlations were found between the occlusal cant and the superior TMJ space on the deviated side (P＜0.05). Negative correlation was found between the vertical height difference of bilateral canines and the anterior TMJ space on the deviated side in the juvenile group(P＜0.05). In the adult group, no significant correlation was observed among those correlated examination (P＞0.05)., Conclusons: The occlusal canting is moderately correlated with mandibular position in the early stage of mandibular deviation patients. Early treatment of mandibular deviation is of great importance in preventing its progression into severe skeletal malocclusion, and more attention should be paid on the correction of the canted frontal occlusion plane.

Due to increasing active nitrogen pollution loads, river systems have become an important source of nitrous oxide (N 2 O) in many areas. Due to the lack of monitoring data in many studies as well as the difficulty in estimating intermediate parameters and expressing temporal-spatial variability in current methods, a high level of uncertainty remains in the estimates of riverine N 2 O emission quantity. Based on the monthly monitoring efforts conducted for 10 sampling sites across the Yonganxi River system in Zhejiang Province from June 2016 to July 2019, the temporal and spatial dynamics of riverine N 2 O dissolved concentrations ρ (N 2 O), N 2 O fluxes, and their influencing factors were addressed. A multiple regression model was then developed for predicating riverine N 2 O emission flux to estimate annual N 2 O emission quantity for the entire river system. The results indicated that observed riverine ρ (N 2 O) (0.03-2.14 μg·L -1 ) and the N 2 O fluxes[1.32-82.79 μg·(m 2 ·h) -1 ] varied by 1-2 orders of magnitude of temporal-spatial variability. The temporal and spatial variability of ρ (N 2 O) were mainly influenced by the concentrations of nitrate, ammonia, and dissolved organic carbon, whereas the N 2 O emission fluxes were mainly affected by river water discharges and ρ (N 2 O). A multiple regression model that incorporates variables of river water discharge and ρ (N 2 O) could explain 90% of the variability in riverine N 2 O emission fluxes and has high accuracy. The model estimated N 2 O emission quantity from the entire Yonganxi River system of 3.67 t·a -1 , with 29% from the main stream and 71% from the tributaries. The IPCC default emission factor method might greatly overestimate and underestimate N 2 O emission quantities for rivers impacted by low and high pressures of human activities, respectively. This study advances our quantitative understanding of N 2 O emission for the entire river system and provides a reference method for estimating riverine N 2 O emission with more accuracy.

Purpose: To investigate the changes of condyle position by decreasing posterior occlusal plane angle in Class II high angle cases., Methods: Fifteen Class II high angle patients, aged from 15 to 30, were treated. Before treatment, ANB>5°, FH-MP>32°, molar relationship was Class II bilaterally. The treatment began with aligning and leveling the upper and lower dental arch, then the upper arch was expanded when necessary. Multiloop edgewise arch wire (MEAW) was used to guide the mandible forward and flatten the posterior occlusal plane. Cone-beam CT(CBCT) was taken for each patient before and after treatment. The anterior, superior and posterior spaces of temporomandibular joint(TMJ) were measured respectively, and the posterior occlusal plane angle was also measured. Paired t test was used to evaluate the changes of condyle position and posterior occlusal plane angle, and pearson correlation coefficients was used to determine the correlation between changes of condyle position and posterior occlusal plane angle using SPSS 19 software package., Results: Class II molar relationship of all patients was improved to Class I, and the profile was improved. Posterior and superior space of TMJ increased by 0.88 mm±0.17 mm and 0.45 mm±0.20 mm on average respectively, and both increases were significant. Posterior occlusal plane was flattened, POP-SN and POP-FH decreased by 3.59°±2.31° and 2.31°±3.62°, respectively, and the decreases were significant. Pearson's correlation test showed no significant correlation between changes of condyle position and posterior occlusal plane angle., Conclusions: In orthodontic treatment of Class II high angle cases, the condyle can be changed to anterior and inferior position by decreasing posterior occlusal plane angle.

The regulation mechanism of arecoline on rat hepatic CYP2E1 was studied in vivo. After oral administration of arecoline hydrobromide (AH; 4, 20 and 100 mg x kg(-1) x d(-1)) to rats for one week, the hepatic CYP2E1 mRNA level remained unchanged, but the hepatic CYP2E1 protein content was dose-dependently increased. Additionally, although the hepatic CYP2E1 activity was induced by AH treatment, the induction was attenuated with the increase in dosage. The results indicate that the effect of arecoline on rat hepaticdoes not involve transcriptional activation of the gene, but largely involves the stabilization of CYP2E1 protein against degradation or increased efficiency of CYP2E1 mRNA translation, and additionally involve the post- ranslational modification of CYP2E1 protein. Furthermore, the CYP2E1 response is fairly equal among the different species, the induction of rat hepatic CYP2E1 by arecoline suggests that there is a risk of metabolic interaction among the substrate drugs of CYP2E1 in betel-quid use human.

Objective: Ceramic brackets debonding by Nd:YAG laser is based on the thermal effect of laser, which may cause injury of the pulp tissue. In this study, the histological changes of pulp tissue that subjected to Nd: YAG laser irradiation with different power and time were observed., Methods: 20 New Zealand rabbits were included in this study. Ceramic brackets were bonded to the 4 incisors as routine. The ceramic brackets of left upper teeth that debonded mechanically were used as control group, while the brackets of right upper, left lower and right lower incisors were debonded by laser with 3 W 3 s (group A), 2 W 5 s (group B) and 5 W 2 s (group C) energies, respectively. The teeth were pulled out at 5 minutes, 1 day, 3 days, 1 week and 1 month after the debonding operations. Slides prepared from the pulp tissues of the debonded teeth were used to evaluate the injury of laser., Results: In comparison with the control group, pulp tissue of teeth that exposed to laser with different energy for 5 minutes showed mild capillary dilation. One day later, group A, B and C showed moderate capillary dilation, and group C also showed moderate infiltration. At 3 days, inflammation was disappeared in group B, whereas capillary dilation was found in group A. Hemorrhage and inflammation cells infiltration were found in group C. At 1 week, alleviation of capillary dilation was found in group A but not in group C. One month later, inflammation disappeared in group A, while pulp tissue in group C showed mild edema and capillary dilation., Conclusion: Nd:YAG laser of high energy may cause injury of the pulp tissue during debonding. Laser energy of 3 W 3 s could effectively debond ceramic brackets without irreversible pulp injury.