Objective This study aimed to explore the relationship between the spontaneous changes of mesiodistal angulation of lower second molars(L2M)and individual clinical characteristics in patients with early permanent dentition correction.Methods A total of 44 patients with a total of 88 mandibular second molars were included in this study after screening.Based on the frequency distribution histogram of the initial angle of inclina-tion(L2M initial angle)of the L2M crown before treatment,it was divided into three groups:Group A:small angle group,L2M initial angle is 0°～17.5°;Group B:medium angle group,L2M initial angle is 17.5°～42.5°;Group C:large angle group,L2M initial angle is 42.5°～60°.According to whether L2M has erupted and exposed most of the crown,it was divided into erupted group and unerupted group.According to the mandibular plane angle,it can be divided into high angle,low angle,and average angle.CBCT reconstructed panoramic images were used to measure the mesiodistal inclination of L2M and analyze the relationship between each group and the change in mesiodistal inclination angles of L2M.Results After treatment,L2M mesiodistal angulation in the small angle,large angle,non-eruption,and high angle groups became more significant.The angle in the middle angle group was significantly smaller.The L2M mesiodistal angulation in the eruption and average angle group did not change significantly.The angles of ANB,Y-axis,and mandibular plane have no correlation with the initial angle of L2M.Conclusion The L2M in patients with large and high angles is more likely to topple during a correc-tion.During the correction,the L2M tends to approach the normal axial inclination.

Different sagittal and vertical malocclusions exhibit different characteristics in the growth,development,and final morphol-ogy of the temporomandibular joint.Different skeletal malocclusions affect the spatial and morphological characteristics of the final tem-poromandibular joint through different growth and development mechanisms.These mechanisms have important guiding significance for determining the etiology and guiding treatment plans of maxillofacial malocclusion in children and adolescents in clinical practice.This article summarized and analyzed morphological differences of the temporomandibular joint fossa and condyle in different sagittal and ver-tical malocclusions,as well as the relative position of the condyle in the fossa.It is found that there is a connection between different maxillofacial malocclusions and the characteristics of the temporomandibular joint,with the vertical direction having a more significant impact on the temporomandibular joint than the sagittal direction;the impact of vertical malocclusion on the temporomandibular joint is mainly reflected in the shape of the joint fossa and the position of the condyle in the fossa.The joint fossa of hyperdivergent malocclu-sion is often relatively low and flat,with the condyle located in the anterior upper position of the fossa.The joint fossa of hypodivergent is relatively narrow and deep,and the condyle is relatively backward and lower in the joint fossa.The possible mechanisms were also elaborated,providing reference for clinicians'comprehensive diagnosis and treatment.

This study was designed to explore the effect of up-regulation of interleukin(IL)-37a expression on lung function and T helper type 1(Th1)/Th2 cytokine balance in rats with acute respiratory distress syndrome(ARDS).Mesenchymal stem cells(MSCs)overexpressing IL-37a were constructed and co-cultured with mononuclear cells,then flow cytometry was used to detect the effect of IL-37a overexpression on Th1 and Th2 expression,and ELISA was used to detect IFN-γ and IL-4 levels in supernatant of the culture medium.Total of 30 SD rats were recruited and randomly divided into control group(sham surgery),ARDS group(lipopolysaccharideinduced establishment of ARDS model),and IL-37a group(ARDS model+tail vein injection of 10 μg/kg IL-37a),with 10 rats in each group.After 12 hours of modeling,arterial oxygen pressure(PaO2)and oxygenation index(PaO2/FiO2)were measured using a blood gas analyzer,and the dry/wet(W/D)ratio of the lungs was measured.HE staining was used to observe lung tissue pathology and evaluate lung pathological injury scores;ELISA was used to detect alveolar lavage fluid(BALF)and serum IL-4 and IFN-γ expression;flow cytometry was used to detect spleen Th1/Th2;while Western blot was used to detect the protein expression of NF-κB and NLRP3 in lung tissue.Data showed that the levels of Th1,Th1/Th2,and IL-4 in the peripheral cells of the overexpression IL-37a group were lower than those in the negative control group cells,while the expression of Th2 and IFN-γ were higher than those in the negative control group cells(P＜0.05).Compared with the control group,the ARDS group showed lower levels of PaO2,PaO2/FiO2,BALF and serum IL-4,but higher levels of W/D,lung pathological injury score,BALF and serum IFN-γ,spleen Th1/Th2,and lung tissue NF-κB and NLRP3 proteins.IL-37a could reverse the changes mentioned above in ARDS rats(P＜0.05).Taken together,up-regulation of IL-37a expression can ameliorate lung injury in ARDS rats,which may be related to the role of IL-37a in inducing MSC differentiation and promoting the restoration of Th1/Th2 balance.

【Objective:】 To construct a questionnaire on medical students’ cognition level of public health ethics, and to provide a scientific and objective evaluation tool for understanding the cognitive level of medical students on public health ethics. 【Methods:】 Based on the literature review and focus group discussion, the initial questionnaire was constructed. The Delphi method was used to conduct three rounds of correspondence with 12 experts, and the final questionnaire was drafted. And exploratory factor analysis and internal consistency were used to evaluate the questionnaire. 【Results:】 In the three rounds of correspondence, the enthusiasms of experts were all 100%, the authority coefficients were all 0.84, the coefficients of variation were 0~0.32, 0~0.26, 0~0.12, respectively, and the coordination coefficients were 0.206, 0.163, and 0.250, respectively (all P<0.05). The analysis of the items showed that the critical ratio values and related coefficients of the questionnaire items were statistically different. The structural validity analysis showed that the cumulative variance contribution rate of the extracted two common factors was 61.015%. The intrinsic consistency reliability analysis showed that the questionnaire Cronbach’s coefficient was 0.956. Finally, the questionnaire of 26 items was formed, including two dimensions: knowledge of public health ethics and application of public health ethics. 【Conclusion:】 The questionnaire on medical students’ cognition level of public health ethics is reliable and has good reliability and validity, and can be used as a tool for medical students’ public health ethics cognition level.