Objective To investigate sodium hydrogen sulfide(NaHS)with function of regulating glutathione(GSH)synthesis to reduce reactive oxygen species(ROS)production in type 2 diabetic cardiomyopathy(DCM).Methods Mouse cardiomyocyte cell line HL-1 was incubated with high concentration of glucose(HG:40 mmol/L)and palmitate(Pal:500 μmol/L)as a cell model of type 2 DCM.HL-1 cells were incubated with NaHS(100 μmol/L),DL-propargylglycin(PPG,1 mmol/L)and N-acetyl-l-cysteine(NAC,5 mmol/L),respectively for 72 hours.The expression of cystathionine-γ-lyase(CSE)and the key enzymes of glutathione production was tested by Western blot.Dihydroethidium(DHE)and dichlorofluoromethane(DCFH)were used to detect the content of ROS in HL-1 cells.Cell viability was detected by CCK8 kit.The content of total GSH was detected.The interaction between muscle specific ring finger protein 1(Murf1)and nuclear factor erythroid-derived 2-related factor 2(Nrf2)and Nrf2 ubiquitylation was determined by co-immunoprecipitation(co-IP).Results Compared with control group,the expression level of CSE,solute carrier family 7 members 11(SLC7A11),glutamate cysteine ligase C(GCLC),glutamate cysteine ligase M(GCLM)and glutathione synthetase(GSS)in HL-1 cells treated incubated with high glucose and palmitate was decreased,however,NaHS was found to restore it.NaHS reduced the content of ROS in HL-1 cells treated with high glucose and palmitate.The interaction between murf1 and Nrf2 was confirmed by co-immunoprecipitation(Co-IP).Compared with NaHS group,the ubiquitylation level of Nrf2 was enhanced in high glucose and palmitate group.Conclusions Sodium hydrosulfide may reduce the ubiquitylation level of Nrf2 and promote the expression of key enzymes of GSH synthesis.

Objective: To analyze the correlation between refractive errors and physical development indicators among primary school students aged 6 to 9, so as to provide a scientific basis for the development of effective prevention and control measures. Methods: A stratified cluster random sampling method was used to recruit 2 833 elementary school students aged 6 to 9 from Guangdong Province for vision screening, ocular biometry, and physical examinations in Octorber, 2020. The Chi square test, t-test, and ANOVA were employed to compare myopia rates and indicator values across different groups. Multiple linear regression models were used to analyze the correlations between height, weight, and body mass index (BMI) with refractive development indicators. Results: The screening myopia rate among primary school students aged 6 to 9 was 16.7%, and the myopia rate increased with age ( χ 2= 51.58 , P <0.01). The height and weight of the myopic group [(126.96±7.41)cm, (26.59±6.45)kg] were higher than those of the non myopic group [(124.76±7.77)cm, (25.42±5.87)kg] ( t =5.84, 3.65, P <0.01). The mean values of spherical equivalent (SE), axial length (AL), anterior chamber depth (ACD), and AL/corneal curvature radius (CR) ratio for students aged 6 to 9 were (-0.17±1.04)D, (22.96±0.78)mm, (3.38±0.24)mm, and (2.95±0.08), respectively, with statistically significant differences across different age and myopia severity groups ( t =37.08, 119.20, 41.54, 133.60; 935.30, 184.10, 73.95, 498.50, P < 0.01). After adjusting for gender, age, and residence, the multiple linear regression model showed that height was positively correlated with AL and CR, weight was positively correlated with ACD, and BMI was positively correlated with AL and ACD ( β = 0.191 , 0.070, 0.035, 0.013, 0.007, P <0.05). When stratified by myopia status, results for the non-myopic group were similar to the overall results, whereas in the myopic group, the correlations between height, BMI, and AL were not statistically significant ( P > 0.05). Conclusions Among primary school students aged 6 to 9, height and BMI are positively correlated with AL in the non myopic group but no similar correlation is observed in the myopic group, indicating that factors other than physical development, such as environmental and behavioral factors, should be considered for their impact on refractive development.

Objective To investigate the function of sodium hydrosulfide(NaHS)to regulate mitochondrial fusion/fission in diabetic cardiomyopathy and underlying mechanism.Methods Db/db mice as type 2 diabetes animal model were treated by NaHS.H9C2 cells incubated with glucose(40 mmol/L),palmitic acid(200 μmol/L,Pal)and oleate(200 μmol/L,Ole)were intervened by NaHS(100 μmol/L).H2C9 cellswere divided into control,HG+Pal+Ole,HG+Pal+Ole+NaHS and Pal+Ole+DJ-1 siRNA+NaHS groups.The protein level of Mfn2,Fis1,CSE,and DJ-1 was determined by Western blot.Mitotracker staining was used to observe the morphology of mitochondria.The ultra-structural alteration of cardiac tissues was detected by transmission electron microscopy.The cardiac functions were detected by echocardiography.Results Expression of Fis1 was increased(P＜0.05)and expression of Mfn2 was decreased(P＜0.05)in db/db and H9C2 treated by HG+Pal+Ole compared to control group.NaHS could upregulate the expression DJ-1,enhance the expression of Mfn2,and reduce the expression of Fis1.In db/db mice,cardiac systolic function was reduced.Disordered arrangement of myofilament,loss of cristae and mitochondrial fission were observed.NaHS could ameliorate these alterations.Conclusions NaHS may alleviate mitochondria injury by promoting mitochondrial fusion.

Objective To analyze mechanical characteristics for stress accumulation of the maxillary complex during expansion until complete fracture of the mid-palatal suture by using the three-dimensional (3D) finite element method, and verify validity of the model. Methods The finite element maxillary complex model containing the microimplants was established. The yield strength of the mid-palatal suture was set, and the transverse displacement of 0.25 mm was loaded every 5 ms as the load until the suture was completely fractured. The CT images of one clinical patient before and after expansion were compared and verified. Results During 0-17 ms, the stress was mainly concentrated around the microimplants, the middle of the mid-palatal suture and the zygomatico-maxillary sutures. During 18-60 ms, cracks began to occur in the mid-palatal suture, and expanded forward and backward. During 61-71 ms, the rupture path was followed by posterior part of the mid, palatal suture-the front part and the back part. Conclusions The 3D finite element model of microimplant-assisted expansion based on fracture mechanics was effective and the calculated fracture process result were more consistent with clinical practice. The research findings provide the mechanical reference model for more effective research on microimplant-assisted palatal expansion in the future.