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The contribution presents the representative research progress on global static gravity field modeling, regional geoid/quasigeoid determination, vertical datum study, as well as the theory, algorithm and software for gravity field study in China from 2019 to 2023, which are the highlights of the chapter 6 “Progress in Earth Gravity Model and Vertical Datum” in the “2019—2023 China National Report on Geodesy” that submitted to the International Association of Geodesy(IAG). In addition, suggestions are proposed to promote the research in the fields of earth gravity field, geoid/quasigeoid and vertical datumin China according to trends of international geodesy and related disciplines.

Purpose: To assess the current prevalence of caries, gingival bleeding, calculus, and fluorosis and to determine the risk factors for caries in permanent teeth of 12-year-old students in Guangdong Province, China.Materials and Methods: A cross-sectional survey was carried out among 1920 12-year-old students in Guangdong Province. All participants were required to undergo an oral health examination. Information concerning the subjects' family background, dietary habits, and relevant oral health behaviour were collected in a structured questionnaire. Chi-squared tests, Wilcoxon rank-sum tests, and the logistic regression model were used in the statistical analysis.Results: The prevalence rates of caries in permanent teeth, gingival bleeding, calculus, and fluorosis were 43.07%, 40.57%, 43.75%, and 5.05%, respectively; the average decayed, missing, and filled teeth (DMFT) index was 1.06±1.721. Residence (odds ratios [OR] rural=1.798, 95% CI: 1.485-2.177), sex (OR female=1.352, 95% CI: 1.121-1.631), paternal education level (OR >9 years=0.755, 95% CI: 0.608-0.936), presence of calculus (OR yes=1.279, 95% CI: 1.057-1.548), and frequency of consumption of sugary snacks (OR frequently=1.418, 95% CI: 1.064-1.890) were statistically significantly associated with the risk of permanent teeth caries.Conclusion: Oral health in 12-year-olds in Guangdong Province remains to be improved. Rural residence, female sex, the presence of calculus, and frequent consumption of sugary snacks could increase the risk of caries. The paternal educational level was negatively associated with the risk of caries, whereas we found no association between the maternal educational level and the risk of caries in this population. [ABSTRACT FROM AUTHOR]

Objective: To investigate the protective effect of Illicium verum extract on the vascularization of osteoporotic fracture in rats, and to elucidate its potential mechanism., Methods: The osteoporotic fracture model was established in ovariectomized rats. Rats were infused with 0.05 ml/kg extract in the stomach every morning. Eighteen rats are then divided into control group, model group, and Illicium verum extract group with 6 rats in each group. To observe the therapeutic effect of Illicium verum extract on osteoporotic rats. Femoral bone mineral density and elastic segment end-point load were evaluated by dual-energy x-ray absorptiometry and three-point bending test. Hematoxylin-eosin staining was used to measure the number and area of callus blood vessels. The serum levels of VEGF and NO were detected by ELISA. Moreover, the expressions of NOX2, NOX4, NRF2, p-PI3K, CyclinD1, VEGF, HIF1α, and eNOS in HUVEC were detected by Western blot. CCK8 and wound healing assay were used to detect the proliferation and migration of HUVEC. Then, the ability of HUVEC to form blood vessels was detected by tube formation assay., Results: Firstly, control group showed the normal pathomorphology and density of femoral bone, and model group showed significantly decreased bone density and consistent with bone microstructure degeneration, destruction, thinning, and fracture of bone trabecular structure vs control group, and illicium verum extract significantly increased femoral density and maximum load, increased the number and area of callus blood vessels and increased VEGF and NO levels in serum vs model group. Then, Illicium verum extract promoted the expression of NRF2, p-PI3K, CyclinD1, VEGF, HIF1α, and eNOS protein in HUVEC, inhibited the expression of NOX2 and NOX4, and enhanced the cell proliferation, migration, and angiogenesis. However, the effect was reversed by the overexpression of NRF2 and the treatment with LY294002., Conclusion: Illicium verum extract protects the vascularization of the osteoporotic fracture model in rats.

Purpose: To assess the current prevalence of caries, gingival bleeding, calculus, and fluorosis and to determine the risk factors for caries in permanent teeth of 12-year-old students in Guangdong Province, China., Materials and Methods: A cross-sectional survey was carried out among 1920 12-year-old students in Guangdong Province. All participants were required to undergo an oral health examination. Information concerning the subjects' family background, dietary habits, and relevant oral health behaviour were collected in a structured questionnaire. Chi-squared tests, Wilcoxon rank-sum tests, and the logistic regression model were used in the statistical analysis., Results: The prevalence rates of caries in permanent teeth, gingival bleeding, calculus, and fluorosis were 43.07%, 40.57%, 43.75%, and 5.05%, respectively; the average decayed, missing, and filled teeth (DMFT) index was 1.06±1.721. Residence (odds ratios [OR] rural=1.798, 95% CI: 1.485-2.177), sex (OR female=1.352, 95% CI: 1.121-1.631), paternal education level (OR >9 years=0.755, 95% CI: 0.608-0.936), presence of calculus (OR yes=1.279, 95% CI: 1.057-1.548), and frequency of consumption of sugary snacks (OR frequently=1.418, 95% CI: 1.064-1.890) were statistically significantly associated with the risk of permanent teeth caries., Conclusion: Oral health in 12-year-olds in Guangdong Province remains to be improved. Rural residence, female sex, the presence of calculus, and frequent consumption of sugary snacks could increase the risk of caries. The paternal educational level was negatively associated with the risk of caries, whereas we found no association between the maternal educational level and the risk of caries in this population.