Objective: To study the correlation between electronic screen use and myopia among primary and secondary school students in six provinces and cities in China, in order to provide a scientific basis for comprehensive prevention and control of myopia. Methods: From November 2020 to June 2022, a total of 16 557 primary and secondary school students from six provinces and cities in China (Beijing City, Liaoning Province, Zhejiang Province, Henan Province, Shaanxi Province, Chongqing City) were selected by stratified cluster random sampling and probability smampling methods, and a questionnaire prepared by Beijing Center for Disease Control and Prevention was used to investigate their electronic screen use. According to Screening Criteria for Myopia in Children and Adolescents, 0.5% mass concentration of compound topicamide eye drops was used to paralyze the ciliary muscle and undergo slit lamp optometry. Chisquare test was used to compare the differences between groups, and binary Logistic regression was used to analyze the association between electronic screen use and myopia. Results: About 58.3% of primary and secondary school students used electronic screens for more than two hours a day on average, and 63.4% of primary and secondary school students used continuously electronic products for more than 15 minutes at a time for nonstudy purposes. After adjusting for confounding factors, parents unrestricted use of electronic screen time and electronic screen time ≥2 h/d were positively correlated with myopia (OR=1.27, 1.13, P<0.05). Gender stratified analysis showed that boys who used electronic screen time ≥2 h/d had a higher risk of myopia (OR=1.15, P<0.05). The results of grade stratification analysis showed that parents unrestricted electronic screen use time and electronic screen time ≥2 h/d were positively correlated with myopia in the lower grade of primary school students (OR=1.34, 1.18, P<0.05). Among the higher grade of primary school students, continuous use of electronic screens for nonstudy purposes for more than 15 minutes at one time was positively correlated with myopia (OR=1.18, P<0.05). There was a multiplicative interaction between total screen time and one continuous screen time (OR=1.04, P<0.05). Conclusions Primary and secondary students in six provinces and cities in China reports excessive electronic screen usage which is associated with myopia. Schools and parents should jointly limit the use of electronic screen among primary and secondary students to reduce the occurrence of myopia.

ObjectiveTo understand the death status of major chronic diseases among the registered residents in Xuhui District， Shanghai from 2007 to 2021， and to analyze the probability and trend of premature death， so as to provide an evidence for the policy-making of disease control and prevention. MethodsBased on the data from the death registration system of the registered residents in Xuhui District， Shanghai from 2007 to 2021， the mortality rate of major chronic diseases， life expectancy without cause of death， potential years of life lost （PYLL）， average years of life lost （AYLL）， and premature death rate were calculated. Joinpoint 4.8 software was used to calculate the annual percentage change （APC） of premature death rate and its trend. ResultsIn 2021， the mortality rate and standardized mortality rate of four major chronic diseases， namely cardiovascular and cerebrovascular diseases， malignant tumors， diabetes mellitus and chronic lower respiratory diseases among the registered residents in Xuhui District， Shanghai was 767.75/100 000 and 234.69/100 000， respectively， accounting for 85.63% of the total causes of death among the residents in Xuhui District， Shanghai. The PYLL， AYLL and PYLL rate were 10 710.00 person-years， 1.49 years per person， and 11.43‰， respectively. Life expectancy increased by 14.91 years after removing the four major chronic diseases. From 2007 to 2021， the premature death rate of chronic diseases among the registered residents in Xuhui District decreased from 9.38% to 7.91% （APC=-1.09%，P<0.05）. Malignant tumors had the highest rate in premature death， and the premature death rate was higher in males than that in females， with a slower rate of decline than in females. Cardiovascular and cerebrovascular diseases， malignant tumors and chronic lower respiratory diseases showed a significant decreasing trend in premature death rate （APC=-1.30%， -1.20%， -5.42%， P<0.05）， while diabetes mellitus showed a significant increasing trend in premature death rate （APC=3.20%， P<0.05）. There was a significant increasing trend in the rate of premature death from diabetes mellitus in males （APC=5.15%， P<0.05） and a decreasing trend in the rate of premature death from diabetes mellitus in females （APC=-0.76%， P<0.05）. ConclusionCardiovascular and cerebrovascular diseases， malignant tumors， diabetes mellitus and chronic lower respiratory diseases are the main causes of death among the registered residents in Xuhui District. The probability of premature death of the residents in Xuhui District from major chronic diseases is at a low level， indicating that the prevention and control of chronic diseases in Xuhui District has achieved some success， but it is still difficult to realize the goals of the Outline of the "Healthy China 2030" Plan. Therefore， it is necessary to comprehensively carry out the control of risk factors such as tobacco use， harmful alcohol consumption， salt intake， hypertension， hyperglycemia and obesity， especially to strengthen the control of risk factors for male residents， as well as early diagnosis and treatment of malignant tumors， cardiovascular and cerebral vascular diseases and diabetes mellitus， and to implement the disease management mechanism to reduce premature death.

Infectious bone defect is bone defect with infection or as a result of treatment of bone infection. It requires surgical intervention, and the treatment processes are complex and long, which include bone infection control,bone defect repair and even complex soft tissue reconstructions in some cases. Failure to achieve the goals in any step may lead to the failure of the overall treatment. Therefore, infectious bone defect has been a worldwide challenge in the field of orthopedics. Conventionally, sequestrectomy, bone grafting, bone transport, and systemic/local antibiotic treatment are standard therapies. Radical debridement remains one of the cornerstones for the management of bone infection. However, the scale of debridement and the timing and method of bone defect reconstruction remain controversial. With the clinical application of induced membrane technique, effective infection control and rapid bone reconstruction have been achieved in the management of infectious bone defect. The induced membrane technique has attracted more interests and attention, but the lack of understanding the basic principles of infection control and technical details may hamper the clinical outcomes of induced membrane technique and complications can possibly occur. Therefore, the Chinese Orthopedic Association organized domestic orthopedic experts to formulate An evidence-based clinical guideline for the treatment of infectious bone defect with induced membrane technique ( version 2023) according to the evidence-based method and put forward recommendations on infectious bone defect from the aspects of precise diagnosis, preoperative evaluation, operation procedure, postoperative management and rehabilitation, so as to provide useful references for the treatment of infectious bone defect with induced membrane technique.

Objective: To explore the association between reading and writing posture with the occurrence of myopia in Chinese children and adolescents, so as to provide a reference for reducing its prevalence among primary and secondary school students. Methods: Using data from the 2020 survey on the current status of hyperopia reserve in primary and secondary school students from six provinces/cities, namely Beijing, Zhejiang, Chongqing, Shaanxi, Liaoning, and Henan selected by multi stage stratified cluster probability sampling method during November 2020 to June 2022. A total 16 782 students who completed the optometry examination of cycloplegia according to the Children and Adolescents Myopia Screening Standard and questionnaire survey were included for analyzing analyze the association between reading and writing posture with myopia. Results: The overall detection rate of myopia among primary and secondary school students was 45.7%, of which 35.0% were primary school students, 84.1% junior high school students, and 90.4% senior high school students. Poor reading and writing posture was found in 73.6% of primary and secondary school students. Adjusting for confounding factors such as gender, school period, region, outdoor time every day, and whether parents were myopic, the results of the multilevel Logistic regression showed that the following factors were positively correlated with myopia:poor reading and writing posture ( OR=1.17, 95%CI =1.07-1.28), never/occasionally reading and writing with a reading distance which was more than one foot away between the eyes and book ( OR=1.28, 95%CI=1.08-1.53, OR=1.23, 95%CI = 1.08- 1.40), teachers occasionally reminding the child of their reading and writing posture ( OR=1.13, 95%CI =1.01-1.25), and often/always reading and writing while lying down or with the face on the arm ( OR=1.15, 95%CI=1.01-1.32, OR=1.46, 95% CI = 1.17-1.82), always reading and writing with the head in the hand ( OR=1.56, 95%CI =1.20-2.01). Further, a negative correlation was detected between myopia and parents occasionally reminding their children of their reading and writing posture ( OR= 0.85 , 95%CI =0.76-0.96) ( P <0.05). Conclusion Poor reading and writing posture is a risk factor for the development of myopia in primary and secondary school students, and interventions for reading and writing posture need to be strengthened to reduce the occurrence of myopia among primary and secondary school students.

Objective To compare the reprogramming effects and biological characteristics of two types of human odontogen-ic induced pluripotent stem cells(iPSCs).Methods Human dental pulp stem cells(DPSCs)and stem cells from apical papilla (SCAP)were isolated and primarily cultured.The Sendai reprogramming system was utilized to induce DPSCs and SCAP into iP-SCs.The morphology,reprogramming efficiency,reprogramming and time were compared between human DPSCs-iPSCs and SCAP-iPSCs.The SeV and exogenous transcriptional gene expression were detected by RT-PCR.Results Human DPSCs and SCAP were reprogrammed as iPSCs with classical ES-like clonal morphology.The reprogramming efficiencies were(0.68 ± 0.02)% and(0.7 ± 0.01)% respectively,the difference was not statistically significant(P>0.05).The reprogramming time was(26.0 ± 2.1)d and (27.0 ± 1.4)d respectively,the difference was not statistically significant(P>0.05).The RT-PCR results showed that no expres-sion of exogenous virus or transcriptional gene sequence in both iPSCs.Conclusion Human DPSCs and SCAP can be reprogrammed as virus-free and transgene-free iPSCs,which are the ideal sources of iPSCs.

The design of research protocol and quality control are the key to ensure the quality of clinical trial. A randomized clinical trial regarding the effects of medication combined with acupuncture on live birth rate in polycystic ovary syndrome (PCOS), which was initially designed as a comparative effectiveness research, then added with an acupuncture control group and finally became a factorial analysis, is taken as an example to explain the protocol design and optimization process, demonstrating the high level of methodology design and international recognization. By a series of measurements, such as unified purchase of acupuncture equipment, multiple trainings and assessments for acupuncturists' knowledge and operation standardization, in-site supervision of local center experts, the standard operation of acupuncture could be ensured and the credibility and scientificity of research results could be improved.

Objective To comparatively study the features of two reprogramming systems of induced pluripotent stem cells (iPSCs)from human dental origin.Methods Two kinds of reprogramming system,i.e.STEMCCA lentivirus /feed layer and Sen-dai virus /matrigel were used to induce human stem cells from apical papilla(SCAP)into iPSCs,respectively.The induction efficien-cies,workload of generating iPSCs,aneuploidy karyotype ratio,complexities of eliminating exogenous transcription factors and spe-cific markers expression were compared between these two systems.Results The STEMCCA reprogramming system required to prepare the feeder cell MEF.The reprogramming efficiency was 0.1%.Transcription gene-free iPSCs cells were obtained by the Cre-loxp enzyme digestion technique at the later stage.Sendai virus reprogramming system was feeder-free and the preparation of matrigel was quite simple with unified standard.The reprogramming efficiency was 0.7%,which was much higher than that of STEMCCA system(P <0.05).The exogenous virus and transgenes could be gradually eliminated after several passages of natural subclone.Conclusion The Sendai virus/matrigle reprogramming system is much more applicable for the induction of iPSCs from dental origin than the STEMCCA system.

Objective To compare the growth characteristics,proliferation and osteo/odontogenic differentiation capability of stem cells from human dental pulp (dental pulp stem cells,DPSCs) and apical papilla (stem cells from apical papilla,SCAP) in vitro.Methods Human dental pulp and apical papilla tissues were separated from impacted third molars of young healthy donors at the age of root development and digested by collagenase type Ⅰ and dispase type Ⅱ to derive primitive DPSCs and SCAP.Cells were then induced for osteo/odontongenic differentiation by medium containing β-glycerophosphate,dexamethasone and KH2PO4.Flow cytometry was utilized to test the expression of specific markers of stem cells,including CD24,CD34,CD45,CD90,CD105,CD146,STRO-1 and OCT-4.AR-S was used to display the mineralization structure and RT-PCR was applied to analyze the expression of bone sialoprotein (BSP),osteocalcin (OCN) and dentine sialophosphoprotein (DSPP).Results Both DPSCs and SCAP were positive for CD90,CD105,CD146,STRO-1 and OCT-4,in percentages varying according to cell type,without expression of CD34 or CD45.Only SCAP expressed CD24 positively.Both cells formed organized mineralization structure after 2 weeks of induction in time-dependent manner,with more mineralization by SCAP and expressed differentiation markers,including BSP,OCN and DSPP.Conclusion Human DPSCs and SCAP possess the characteristics of MSCs and could be differentiated into odontonblast-like cells in vitro.Both cells are approachable stem cell sources for dental tissue engineering.

Objective To explore the miRNA regulating the potential cancer-promoting gene CCL18 in cutaneous malignant melanoma.Methods Bioinformatics analysis was conducted by using online software miRanda and TargetScan,so as to predict the miRNA targeting CCL18 gene.Three kinds of C CL18 3'UTR dual-luciferase reporter vectors,including mutant 3'UTR vector (mutant 3'UTR group),wildtype 3'UTR vector (wild-type 3'UTR group) and empty vector (blank control group),as well as miRNA vectors carring selected miRNAs were constructed according to human gene sequence analysis,and then were used to co-transfect 293T cells.After 48-hour treatment,the cells were lysed for detection of luciferase activity.Real-time fluorescence-based quantitative PCR was performed to measure the expression of CCL 18 and selected miRNA in 14 fresh malignant melanoma tissue specimens and 14 paracancerous normal skin tissue specimens (control tissues),and their correlations were analyzed.Results Online software analysis showed that some miRNAs were identified to target the 3'UTR of CCL18 gene,including miR-183,miR-128 and miR-33a.Luciferase reporter vectors and miRNA vectors were constructed successfully.As luciferase activity assay showed,when miR-183 and miR-128 were bound to the CCL18 3'UTR,the luciferase activities were significantly higher in their mutant 3'UTR groups (11.63 ± 0.42;8.80 ± 0.49) than in their wild-type 3'UTR groups (4.86 ± 0.39;5.01 ± 0.54;both P ＜ 0.05) and blank control groups (2.41 ± 0.13;2.39 ± 0.05;both P ＜ 0.01),while there were no significant differences between miR-33a-hinding mutant 3'UTR group (6.41 ± 0.47) and miR-33a-binding wild-type 3'UTR group (6.16 ± 0.22,P ＞ 0.05).Real-time fluorescence-based quantitative PCR revealed higher mRNA expression of the CCL18 gene (3.52 ± 1.68),but lower expression of miR-183 (0.49 ± 0.32),miR-128 (0.30 ± 0.20) and miR-33a (0.46 ± 0.40) in the malignant melanoma tissues compared with the control tissues.The mRNA expression of the CCL18 gene was negatively correlated with the expression of miR-128 (rs =-0548,P ＜ 0.05),but showed no significant correlations with the expression of miR-183 and miR-33a (both P ＞ 0.05).Conclusion miR-128 may play a role in regulating the potential malignant melanoma-promoting gene CCL18.

Objective To comparatively study the characteristics of 3 kinds of culture substrates of human odontogenic induced pluripotent stem cells(iPSCs).Methods The human odontogenic iPSCs were cultured by 3 kinds of substrates:mouse embryonic fibroblasts(MEF),matrigel and recombinant human vitronectin(VTN-N).The iPSCs growth situation was compared among three groups.Results The preparation time of these 3 kinds of substrates was 14,3,1 hlespectively,and,the difference was statistically significant (P＜0.05).The iPSCs reprogramming time was (30± 1.6),(26 ± 2.1),(27 ± 1.4) d,lespectively,wht that in the MEF group significantly higer than in other two groups (P＜0.05).The reprogramming efficiencies were 0.3 ％ ± 0.03 ％,0.56 ％ ± 0.08 ％,0.7 ％ ± 0.02 ％ respectively (P＜ 0.05).Three kinds of substrate could better support iPSCs growth and make them to maintain un-differentiation status.Conclusion with no heterologous animal components,and the adrantaga of simple pleparation,oonfrollable standard and shorter gramming time is easy to prepare,the standard is controllable and the reprogramming time is shorter,which is an ideal substrate for supporting iPSCs growth.