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BackgroundThe narratives of hierarchical medical sytem are generally classified into two patterns, one is the policy narrative, which is used to persuade the target audience to gain their support in practice, and the other is the academic narrative, which describes the thinking process of researchers to explore problems and enhance perceptions using words. The narratives of the hierarchical medical system are rich and diverse, but have been rarely systematically reviewed and summarized.ObjectiveWe explored the evolution process, focuses and characteristics of academic narratives of 10-year development of hierarchical medical system in China using social network analysis, aiming to provide a reference for improving the implementation of hierarchical medical system.MethodsOn March 21, 2021, we searched the database of CNKI for studies regarding hierarchical medical system in China published in academic journals in Chinese during January 1, 2009 to March 21, 2021 using "hierarchical medical system" "seeking healthcare in an orderly way" "seeking diagnosis and treatment services in an orderly way" "division of healthcare" "division of diagnosis and treatment" "first contact in primary care" "treating acute and chronic diseases separately" "cooperation between tertiary and secondary/primary hospitals" "bi-directional referrals" as keywords. Bibliometric methods, SATI 3.0 and UCINET 6.0 were used to explore the process, focuses and characteristics of academic narratives of hierarchical medical system through time series analysis, high-frequency keywords analysis, centrality analysis and small group analysis, and to generate visualized co-occurrence network diagrams of high-frequency keywords.ResultsA total of 4 882 studies were included for analysis. According to the results of time series analysis, the development of the hierarchical medical system could be roughly divided into three stages: embryonic stage (2009—2013) , acceleration stage (2014—2017) and standardization stage (2018 to present) . In terms of the use of frequency, the top five high-frequency keywords were "hierarchical medical system" "medical consortium" "primary healthcare institutions" "bi-directional referrals" and "public hospitals". In terms of closeness centrality, the top five high-frequency keywords were "hierarchical medical system" "medical consortium" "primary healthcare institutions" "bi-directional referrals" and "general practitioners". Small-group analysis yielded three groups of word clusters: core word clusters (including "medical consortium" "reform of public hospitals" "bi-directional referrals" "general practitioners" and "first contact in primary care") , secondary word clusters (including "the internet" "internet-based healthcare" "internet-based hospital" and "telemedicine") , and marginal word clusters (including "diabetes" "chronic disease" "cognition" and "influencing factors") . Health policy rhetoric was an important part of the core word clusters. And secondary and marginal word clusters were constantly evolving and generating.ConclusionThe academic narratives of hierarchical medical system have gradually derived from the mutually-promoted development of policies and real implementation regarding the hierarchical medical system, generally demonstrated various structures and relatively homogeneous research direction. Available academic and policy narratives of the hierarchical medical system are still limited to the scope of guiding principles, and the implementation of the concept and system still relies on the top-down push from the policy-making level, while the self-motivated micro-practices of hierarchical medical system in primary care have not yet emerged.

Background: Screen exposure, particularly recreational screen exposure, is an integral part of children's lives. However, little is known about how family factors influence children's excessive screen exposure, especially in the context of 69 million left-behind children experiencing parent–child separation in China. This study mainly concentrates on the correlation between parental migration, type of caregiver, depression and disciplinary practices of the caregiver and children's screen exposure, including average daily screen time (on weekdays or weekends) and screen content (recreational activities or learning activities). Methods: For a cross-sectional study, we collected data of family basic features, parental migration status and children's screen use in the past week from caregivers of 1,592 children aged 1–66 months in Anhui province. Children were classified into left-behind children (LBC), previously left-behind children (PLBC) and never left-behind children (NLBC) based on their parental migration. Multiple linear regression and binary logistic regression were used to identified the association between family factors and children's screen exposure. Results: Overall, PLBC had higher rates of screen exposure, as well as higher average daily exposure times, than NLBC and LBC. The results of logistic regression showed that PLBC had a higher likelihood of excessive screen use compared to NLBC (60 min/day, OR = 1.40, p < 0.05; 120 min/day, OR = 1.76, p < 0.05). The higher the score of disciplinary practices, the less time children spent on screens for entertainment (B = -3.37, p < 0.01). Conclusions: Our findings provide insights into the risks of children's screen exposure in different contexts of parental migration. The study emphasizes the urgent need to pay attention to PLBC's screen use and to strengthen caregivers' discipline and supervision over children's screen exposure. [ABSTRACT FROM AUTHOR]

The electromagnetic force dynamic installation (DI) method of interference fit fasteners has significant advantages in improving the quality of the assembly interface of composite structure. This study aims to investigate how improving assembly interface quality may help in achieving high‐precision interference‐fit joints in composites. Single‐lap joint specimens were prepared using electromagnetic installation technique, the fatigue life and failure behaviors of the joints under different bolt‐hole clearances were measured and analyzed experimentally. In addition, a three‐dimensional finite element model was developed to predict the radial pre‐compression stresses around the hole and the progressive failure behavior of various typical damage modes in carbon fiber‐reinforced polymer induced by the interference. The results show that the critical interference range for the DI‐composite bolted structure is 1.0%–1.2%. The fatigue life of the best interference (1.0%) and the worst interference (0%, neat fit) have a difference of 36 times in amplitude. The residual stress with uniform distribution and high amplitude reduces the stress concentration of the hole wall and improves the failure evolution of the loaded hole. The contribution of this study provides vital guidance for improving the fatigue performance of CFRP bolted structures using a novel DI method. Highlights: I = 1.0% is the critical damage‐enhancing interference size for dynamically installation interference fit bolts with electromagnetic forces.The residual stress amplitude introduced by the interference does not increase uniformly as the interference size increases. Excessive interference significantly reduces the uniformity and magnitude of residual stresses.Under subsequent cyclic loading, the fifth layer near the inlet and outlet of the extruded lower laminate appears to be the critical ply of extrusion deformation, and severe damage is concentrated in the critical ply of deformation.The decrease of stress amplitude and the variation of mean stress are the mechanisms of fatigue life enhancement in interference fit joints under external cyclic loading. [ABSTRACT FROM AUTHOR]

The nuclear data of Th is primary interest for the thorium-uranium (Th-U) fuel cycle, and its nuclear data accuracy is related to the conversion performance of Th-U fuel cycle. Based on the photo-neutron source for the thorium molten salt reactor (TMSR-PNS), the total cross section (TCS) of ThO2 was measured by the transmission method for the high purity thorium oxide (ThO2) samples. ThO2 samples which the thicknesses were respectively 0.9 cm and 0.608 cm were made by pressing and sintering process at 1 800 ℃. Based on the different pulse shapes of neutrons and γ-rays (n/γ) signal from the lithium iodide (LiI) scintillator detector used for the time-of-flight (TOF) calculation, γ-rays were identified by pulse shape discrimination (PSD) method to reduce the interference of the measured cross section. Combined with the trough position of TOF spectrum and its corresponding energy for the calibration targets of Ag, In and Cd, the flight distance was fitted to be 5.899 m, so as to convert TOF spectrum of neutrons into energy spectrum. Energy spectrum of 10 cm thickness boracic polythene sample was measured to deduct the influence of the scattering neutron from the background. According to the measured neutron leakage spectrum with or without ThO2 sample, experimental data of TCS for ThO2 were obtained. TCS of 16O from ENDF/B-Ⅶ.1 was deducted from TCS of ThO2 and TCS of Th was obtained. Combined with error of the sample purity and thickness, the fitting flight distance, relative standard deviation of TCS for 16O from ENDF/B-Ⅶ.1, and experimental statistical error, the uncertainty of experimental data were calculeted to be 3.25%-4.51% in the energy range from 0.02 to 0.1 eV. The results show that the measured data of TCS of Th are good agreement with the evaluated data of ENDF/B-Ⅶ.1 in the energy range from 0.02 to 0.1 eV. In the thermal energy range (E

The application of a no-touch technique to create an autologous radiocephalic arteriovenous fistula might improve the patency rate. In the present report, we have expanded the concept of the no-touch technique by introducing a modified no-touch technique in which we preserve the perivenous vascular tissue, followed by a functional end-to-side anastomosis to create a radiocephalic arteriovenous fistula with early maturation for hemodialysis.