Objective: To describe the epidemiological characteristics of suicide death and self-harm/suicide in China from 2006 to 2016. Methods: Data in this study are from the datasets of National Death Cause Surveillance from 2006 to 2016 and the National Injury Surveillance Dataset 2016. The age-standardized death rate based on the population census in 2000 was used to describe the trend of suicide over years. This study also described the epidemiological characteristics of suicide death and the demographic characteristics, suicide methods and severity of patients who sought medical help after committing suicide or self-inflicted injury in 2016. Results: Age-standardized suicide mortality had been declining from 9.23/100 000 in 2006 to 5.33/100 000 in 2016 by 42.25%. Suicide mortality increased with age. In 2016, the suicide mortality in China was 7.05/100 000, and among people over 85 years old was 49.49/100 000. In 2016, the dominant two suicide methods were poisoning (39.12%) and sharp injury (25.62%). The first leading method of suicide in rural population, urban population and young people aged 10-to 17-year-old was poisoning (65.13%), sharp injury (29.90%) and fall (25.47%), respectively. As age increased, the severity of suicide/self-inflicted injury increased. The proportions of serious cases among young people aged 10-to 17-year-old and older people aged 60 years old and above who sought medical help after committing suicide or self-inflicted injury were 4.88% and 26.86%, respectively. Conclusion China′s suicide mortality has been declining and special attention should be given to the suicide of old people.

Objective: To analyze the current situation and the trend of the death due to foreign body in airway in children less than 5 years old in China from 1990 to 2017. Methods: Using the mortality data of foreign body in airway in China from 1990 to 2017 from the Global Disease Burden 2017 (data covered 31 provinces, autonomous regions, municipalities, as well as Hong Kong and Macau Special Administrative Regions, excluding Taiwan Province) to describe the death status of children under 5 years old due to foreign body in airway in China, and to calculate the relative change and 95% uncertainty interval (UI) of mortality rate and proportion of children under 5 years old due to foreign body in airway between 1990 and 2017. The robust linear regression was performed with the first-order lag of mortality, and the supremum Wald test was used to explore whether the mortality trend had obvious structural changes around a certain time point. Results: In 2017, the mortality rate of children under 5 years old due to foreign body in airway in China was 8.57/100 000 (95%UI: 7.41/100 000-9.57/100 000), and there was no significant difference between boys (9.05/100 000, 95%UI: 6.82/100 000-10.23/100 000) and girls (8.02/100 000, 95%UI: 7.02/100 000-9.12/100 000). The supremum Wald test showed that there was a structural change around the year of 2005 (P<0.001) in terms of the mortality rate of foreign body in the airway among children under 5 years old, which depicted a relatively stable trend before 2005 and a significant downward trend after 2005. Compared with 1990, the mortality rate of foreign body in airway among children, boys and girls under 5 years old in 2017 decreased by 49.32% (95%UI: 37.78%-65.41%), 41.22% (95%UI: 25.68%-68.26%) and 56.91% (95%UI: 44.78%-66.70%), respectively; the mortality proportion of foreign body in airway among increased by 153.33% (95%UI: 75.99%-204.56%), 171.05% (95%UI: 48.75%-239.63%) and 137.90% (95%UI: 86.62%-198.09%), respectively; the rank of foreign body in airway in all disease increased by 6 and became the first leading cause of injury from the second. Conclusion From 1990 to 2017, the mortality rate of foreign body in airway among children, boys and girls under 5 years old in China generally showed a downward trend. Compared with 1990, the mortality proportion of foreign body in airway among these population increased by a relatively large extent in 2017.

Objective: To investigate the mechanical effects during en-mass retraction of maxillary anterior teeth with clear aligner using three-dimensional finite element method. Methods: Cone-beam CT (CBCT) was used to scan a female orthodontic patient (26 years old, from Department of Orthodontics, Stomatological Hospital of Chongqing Medical University) whose maxillary first premolars were extracted and maxillary dentition had been aligned and leveled. A finite element model including maxillary teeth-periodontal ligament (PDL)-alveolar bone-clear aligner was established by using Mimics 17.0, SolidWorks 2016 and Geomagic Studio 2015 software packages. The process of 0.2 mm en-mass retraction of anterior teeth using clear aligner was simulated by using non-linear contact method of Abaqus 6.14. The trend and displacement of maxillary teeth, the stress distribution of PDL and alveolar fossae, and the deformation trend of clear aligner were obtained and analyzed. Results: Under the experimental condition, lingual crown tipping and distal tipping movement of anterior teeth were observed, and all of them had the tendency of overbite increasing.The maximum displacement of the central incisor, lateral incisor and canine were 25.16, 50.34 and 24.98 μm, respectively. Meanwhile, the second premolar, first molar and second molar had the tendency of mesial tipping movement, and the maximum displacement of them were 33.04, 2.90 and 16.63 μm, respectively. The stress distribution both at the PDL and alveolar fossae were consistent with tooth movement pattern. It was noted that the stress in the PDL of the canine and second premolar were comparatively big, and the corresponding apical areas of alveolar fossae appeared stress concentration. Concurrently, it was found that the clear aligner showed stress concentration at the junction of adjacent teeth with a tendency of crown directional dislocation. Conclusions During en-mass retraction of anterior teeth with clear aligner, attention should be paid to the overbite and torque in anterior teeth, and the anchorage protection of posterior teeth. At the same time, we should be careful of root resorption of the teeth on both sides of the extraction space.

Objective: To describe the trends and potential reasons responsible for injury mortality among children under 18 years old in different stages of the China Children’s Development Outlines (CCDO) for children from 1990 to 2017, in China. Methods: Data derived from the Global Burden of Disease 2017 (GBD2017) were used to analyze the change of injury mortality, among children under 18 years old, by sex and provinces. Results: Since 1990, the Chinese government had formulated and implemented three CCDOs on Children. Each CCDO proposed corresponding main targets and strategic measures based on the development of children under current situation, in each area, accordingly. The first two CCDOs failed to set clear targets for child injury prevention and control, but the third one did propose a quantifiable target. The injury mortality rate of children under 18 years old showed a declining trend in all periods of the three CCDOs, by 26.07%, 40.68% and 26.48%, respectively. Both boys and girls showed significant downward trend in these three stages. Mortality rate on child injury differed in these three stages in all the 31 provinces. Conclusion Thanks to the contribution of CCDO in different stages that providing important policies and impetus for the prevention and control of child injury, the number of deaths caused by child injury kept reducing, from 1990 to 2017, in China.

Objective: To analyze and compare the disease burden of falls in Chinese population aged 0-19, in 1990 and 2017. Methods: Indicators including number of deaths, mortality rates, years of life lost due to premature mortality (YLL), years lived with disability (YLD) and disability-adjusted of life years (DALY), on falls, were gathered from the Global Burden of Disease (GBD) 2017 and used to describe the disease burden and corresponding parameters on falls, between 1990 and 2017, in China. Results: In 2017, number of death, YLLs, YLDs, DALYs caused by falls were 5 321, 0.43 million person years, 0.14 million person years and 0.57 million person years respectively, among aged 0-19 group. Rates on standardized mortality, YLLs, YLDs and DALYs on falls were 1.76/100 000, 141.49/100 000, 46.99/100 000, and 188.48/100 000, respectively. The burden of falls decreased with the increase of age. Compared with 1990, disease burden of falls decreased in all age groups, both in male and female, with more seen in the lower age groups. Compared with 1990, the number of deaths, rates on YLLs, YLDs and DALYs caused by falls decreased by 65.08%, 46.63%, 47.38% and 36.33% respectively, in 2017. However, the YLDs rate increased by 73.31% between 1990 and 2017. The ratio of YLLs to DALYs decreased from 90.84% in 1990 to 75.07% in 2017, with a proportion as 17.36%. Conclusion Compared with 1990, although the disease burden of falls among aged 0-19 group showed a decreasing trend, falls still caused serious disease burden for the aged 0-19 group. Research that targeting prevention on falls, should be continued.

Objective: To understand the injuries among 16 459 left-behind children from 27 poor rural areas in 12 provinces of China, 2016. Methods: Data were collected from the survey of 'Health Service Needs Assessment’ (HSNA) program on left-behind children, from poor rural areas in the middle and western parts of China. Factors including causes, types, locations, related activities, ways of treatment and outcomes among left-behind children with injuries in 2016, were described and analyzed by gender and age groups. Results: In 2016, per-person and person-time incidence rates of injuries were 8.88% and 11.21%, among the 16 459 left-behind children from 27 poor rural areas in 12 provinces of China, both higher in boys, than in girls. Most injuries were unintentional with its proportion higher in older children. The main types of injuries were seen as falls, blunt and sharp injuries, with burns and animal injuries more common in younger children. Injuries among left-behind children mainly took place at home, kindergarten/school, and on the highways/streets/roads, during playing. Most common ways of treatment would include at the emergency settings, self-treated, with older children more likely to treat by themselves. Most injuries were cured. Conclusions In programs on prevention and control of injuries targeting the left-behind children in poor rural areas, special attention should be given to older boys, on falls and blunt/sharp injuries, at home or kindergarten/school. Education programs should pinpoint on self-rescue skills and guidance on kids by the parents, with behavioral norms and social support included. Related comprehensive prevention and control mechanism should be developed in families, schools and communities, with medical resources and insurance mechanism explored to serve these population and districts, including those left-behind children.

Objective: To establish the model of the self-confidence, motivation and authoritative advice factors influencing the use of child restraint and use structural equation model to test it to provide scientific basis for promoting the advocacy of use of child restraint. Methods: Using multi-stage cluster random sampling method, 9 112 parents from the family with one or more private cars and 0-6 years old children in Shanghai and Shenzhen were investigated about the use of child restraint. A theoretical model of the self-confidence, motivation and authoritative advice factors influencing the use of child restraint was constructed. The theoretical model was validated and quantitatively analyzed by structural equation model. Results: The overall model accords with the expected theoretical model, and the goodness of model fit was fine. The indicators had met the standard. RMSEA=0.03, CFI=0.97. The standardization coefficients of each route showed statistical significance (P<0.05). The standardization coefficients of the influence of authoritative suggestions and motives on self-confidence were 0.45 and 0.30 respectively, and the standardization coefficients of the influence of self-confidence on the use of child restraint was 0.40. The standardization coefficient of the influence of authoritative suggestions on motivation was 0.61. Conclusions In the advocacy of the use of child restraint, we should attach importance to the use of recommendations from experts and organizations with professional authority, good credibility and public welfare. We should take the status of children’s road traffic safety and the mechanism of the role of child restraint as one of the key points of propaganda.

Objective: To understand the current situation of road traffic injuries among primary and secondary school students in Mengzi city. Methods: Using the cluster random sampling method, more than 9 000 primary and secondary school students from 20 primary and secondary schools in Mengzi city, were randomly sampled. A questionnaire survey was conducted on the occurrence of road traffic injuries in school students. Results: A total of 9 197 students were surveyed, including 150 from road traffic injuries. The incidence rates of road traffic injuries was 1.63% among students in Mengzi city and 2.85% among junior high school students, with the high incidence in May. The leading places of injuries were village roads (38.00%), city roads (33.33%) and district roads (12.67%), respectively. 26.67% of the traffic injuries occurred on the way to or from schools, with riding on electric bicycle (52.00%) as the major cause and contusion/abrasion (75.33%) appeared as the major signs. Both lower and upper limbs plus multiple parts were accounting for 45.51%, 22.16% and 16.17%, respectively of all the injuries. 70.67% of all the cases with road traffic injuries in children, recovered after treatment. Children with road traffic injuries would stay in the hospital for up to 90 days but spent less than 30 000 Yuan. Conclusion The incidence of road traffic injuries among students in Mengzi city seemed relatively high, with junior high school students reached the highest. Riding electric bicycle appeared as the leading cause for traffic injuries in children in Mengzi city of Yunnan province.

Objective To study the effect of contusion and exhaustive exercise on satellite cells' activation and Pax7/CBF1/DAPT contents in skeletal muscles of rats,and reveal the repair mechanism of the skeletal muscle injury.Methods Twenty-four seven-week-old male Sprague-Dawley(SD)rats were randomly divided into a control(C)group,an immediately after exhaustive exercise(E0)group,a 24 hours after exhaustive exercise(E24)group and a 48 hours after exhaustive exercise(E48)group,each of 6.Other 18 SD rats were randomly divided into 3 groups,6 rats in each group:an immediately after contusion group(D0),a 24h post-contusion group(D24)and a 48h post-contusion group(D48).All groups were killed at different time points after exhaustive exercise and the contusion respectively while the control group was at resting state,and their serum was extracted.The right gastrocnemius muscles were resected and divided into 2 parts:one was used immediately for culturing satellite cells,while the other was stored in the bridge at-80℃.All the serum and gastrocnemius muscles were tested for Pax7,CBF1 and DAPT contents using the enzyme-linked immunosorbent assay(ELISA).Moreover,three-day-old newborn rats were also slaughtered for the above experiment.Results The results of culture in vitro showed that one day after the culture began a small amount of spindle satellite cells could be seen in the newborn rats,but the satellite cells of other groups were growing slowly.However,on the third day and the fifth day,the spindle satellite cells of each group began to proliferate in quantity and reached the peak.Then all the satellite cells had a good proliferation until the seventh day after serial passage,and some patial fusions to microtubules occurred.The biggest cell number and proliferation rate was in newborn rats,but no skeletal muscle satellite cell was found in the control group.At the same time,the number and the proliferation rate of skeletal muscle satellite cells in contusion groups were significantly higher than the exhaustive exercise groups.The results of Elisa showed that the contents of CBF1 and Pax7 in skeletal muscles in exhaustive groups and contusion groups,were significantly upregulated,compared to the control group(P＜0.05).Amomg them,the CBF1 content in group D0,together with the Pax7 content in group D24 and D48,was significantly higher than that of the other groups(P＜0.05).On the other hand,the content of DAPT in skeletal muscles of exhaustive groups and contusion groups,compared to the control group,was significantly downregulated (P＜0.05).To be more specific,the value of group D0 was significantly lower than that of the other groups (P＜0.05).However,there was no significant difference in it among group E0,E24 and E48.Conclusions Contusion and exhaustive exercise can activate the skeletal muscle satellite cells to proliferate and differentiate.The number of activated skeletal muscle satellite cells in the contusion groups is significantly larger than that of exhaustive groups maybe due to the stronger stimulating by contusion.Both contusion and exhaustive exercise increase the contents of Pax7 and CBF1 in skeletal muscles,but decrease that of DAPT.The Pax7 and CBF1 may play a positive regulating role in terms of activating skeletal satellite cells and repairing skeletal muscle injury,while DAPT may play a negative regulating role.

Objective: To understand the status and trend of the mortality rate of falls in different gender, age groups and provinces in China from 1990 to 2015, to explore the number of subgroups of different trends in all provinces, and to determine the different trajectory of subgroups. Methods: Using the mortality rate of falls in China from 1990 to 2015 from the Global Disease Burden 2015 (data covers 31 provinces, autonomous regions, municipalities, as well as Hong Kong and Macau Special Administrative Regions, excluding Taiwan Province) to describe the status of the mortality rate of falls in different gender, age group and provinces in China 2015 and to calculate the corresponding relative change. Using log linear model to calculate the annual percent changes from 1990 to 2015. The number of subgroups and corresponding characteristics of different trajectories were analyzed by trajectory model to analyze with four indicators, P value of the coefficient of independent variables with different orders in all subgroups, Bayesian information criterion, log Bayes factor and average posterior probability. Results: In 2015, the age standardized mortality rate of falls in China was 8.38/100 000 (95%UI: 5.54/100 000-9.30/100 000), which was higher in men (10.81/100 000, 95%UI: 6.58/100 000-12.14/100 000) than that in women (5.84/100 000,95%UI: 3.41/100 000-6.62/100 000), and in the elderly aged 70-year-old and above (60.50/100 000, 95%UI: 38.36/100 000-67.75/100 000) than that in other age groups. From 1990 to 2015, there was no obvious change in the age standardized mortality rate of falls in total population, men and women with average percent change about 0.37 (95%UI: -0.08-0.83), 0.45 (95%UI: 0.05-0.84) and 0.31 (95%UI: -0.26-0.87) respectively, but a significant decrease and increase could be seen in children under 15-year-old, especially under 5-year-old with average percent change about -4.07 (95%UI: -5.62--2.51), and the elderly aged 70-year-old and above with average percent change about 1.89 (95%UI: 1.42-2.37) respectively. Four types of trajectories could be categorized for different trends of age standardized mortality rate of falls in all provinces. The first group had the lowest fall mortality with a downward trend. The fall mortality was close in the second and third group but with different change tendency, a decreasing propensity in the former and an increasing one in the latter. The fourth group had the highest fall morality with obvious fluctuation. Conclusion There was no significant change in the age standardized mortality rate of falls in China from 1990 to 2015. However, the trend of age standardized mortality rate of falls varied in different age and provinces during the same period of time.