Background Fatigue among distribution network live-line workers in complex operational environments has become increasingly severe and requires widespread attention. Objective To investigate the positive rates of fatigue and associated influencing factors of live-line power distribution workers, and to make a reasonable strategy to reduce the fatigue of front-line workers. Methods Power supply companies in Guangdong, Guangxi, and Yunnan provinces were selected by cluster sampling in 2023, and all front-line live-line workers in the selected companies were recruited. The questionnaire used in this study consisted of two parts: one was the Fatigue Scale-14 (FS-14) for investigating fatigue status and the other was for associated influencing factors. A FS-14 score greater than 3 points was defined as fatigue. \begin{document}$ {\chi }^{2} $\end{document} test and logistic regression were employed to analyze the factors affecting fatigue. Results A total of 1341 questionnaires were distributed, and 1217 valid questionnaires were recovered, with a valid response rate of 90.75%. The average fatigue score of the participants was (6.84±3.79) points, and a total of 1054 participants scored over 3, resulting a fatigue positive rate of 86.6%. The logistic regression model showed that working under extreme weather (OR=2.03, 95%CI: 1.38, 2.98), overtime 2-3 times a week (OR=5.24, 95%CI: 1.28, 21.40), overtime everyday (OR=6.95, 95%CI: 1.71, 28.27), frequent wrist rotation (OR=1.95, 95%CI: 1.08, 3.51), and leaning back slightly (OR=2.94, 95%CI: 1.19, 7.28) associated with higher positive rates of fatigue. Conclusion The high positive rate of fatigue among live-line power distribution workers suggests severe fatigue issues. Extreme weather conditions, working overtime frequency, and maintaining wrist rotation and backward bending postures during work are main factors affecting their fatigue.

Background When live working line operators engage in upper limb operations, working for a long time with raising arms and the exposure to adverse ergonomic factors tend to increase muscle load, cause fatigue accumulation, and increase the risk of work-related musculoskeletal disorders (WMSDs). Objective To analyze work posture and associated muscle fatigue during executing breaking/connecting contact terminal, and identify adverse ergonomic factors of the work process. Methods This study recruited 10 volunteers to perform breaking/connecting contact terminal simulation. At a distance of 4.5, 3.5, and 2.5 m from the body to the wire, each performed the task 5 times. Visual 3D was used to analyze the kinematic data from motion capture. The surface electromyography (sEMG) signals of the deltoid, biceps, triceps, and brachioradialis were recorded during the simulation and analyzed for muscle fatigue using root mean square (RMS), median frequency (MF), and jointed EMG amplitude and spectrum analysis (JASA). After completion of each task, Borg scale was used to query the volunteers of their subjective fatigue. A 2-min rest was required between each distance. Results The kinematic data from motion capture showed that in the entire process of the task, the right upper limb was higher when lifting, with the right shoulder joint maintaining flexion and fluctuating periodically between abduction and adduction, external and internal rotation, the right elbow joint maintaining flexion and supination. The frequency of task cycle showed a significant effect on the Borg scale scores (P<0.001, partial \begin{document}$ {\eta }^{2} $\end{document}=0.464); the distance showed no significant effect on the Borg scale scores (P>0.05, partial \begin{document}$ {\eta }^{2} $\end{document}=0.002); their interaction effect was not significant (P>0.05, partial \begin{document}$ {\eta }^{2} $\end{document}=0.020). The results of the sEMG signals showed that at a distance of 4.5 m, the volunteers had the highest percentages of maximal voluntary electrical activation (MVE%) in the deltoid and right brachioradialis and the lowest MF values in the deltoid and left brachioradialis after completing 5 task cycles. The results of JASA showed that fatigue was observed in brachioradialis and deltoid after completing 5 task cycles at a distance of 4.5 m, the right deltoid and right brachioradialis at a distance of 3.5 m, in the brachioradialis, deltoid, and left bicep at a distance of 2.5 m. Conclusion The subjective fatigue of workers who engaged in breaking/connecting contact terminal elevates with more repetitive operations. Based on the sEMG and motion capture analysis, it can be found that improper distance between the workers and the target work area can increase the burden from poor posture and improper use of work equipment, and lead to muscle fatigue; the deltoid and brachioradialis are the key muscles of fatigue in this type of operation; changing the angle of the elbow joint and the shoulder joint during the process of the operation can affect the deltoid and brachioradialis exertion and loading.

Background Power grid is an important component of the national infrastructure. The occupational health issues among the workers in this industry are attracting great concern nationwide. Objective To investigate the prevalence of work-related musculoskeletal disorders (WMSDs) in neck and shoulder among the power distribution workers of power supply enterprises, and analyze the related influencing factors. Method In April 2023, a total of 1244 workers in 50 municipal power supply bureaus were randomly selected from the three provinces under China Southern Power Grid using cluster sampling method. The questionnaire used in the study was based on a revised Musculoskeletal Disorders Questionnaire and added ergonomic load of upper limb work. \begin{document}$ {\chi }^{2} $\end{document} test and logistic regression model were used to explore the influencing factors of neck pain and shoulder pain among the subjects. Results A total of 1244 valid questionnaires were recovered and the effective recovery rate was 90.87%(1244/1369). The positive rates of neck pain and shoulder pain were 45.5% (566 cases) and 36.3% (452 cases) respectively. The logistic regression analysis results showed that more than 20 years working age (OR=2.27, 95%CI: 1.39, 3.96; OR=2.56, 95%CI: 1.53, 4.26), often (OR=2.08, 95%CI: 1.35, 3.20; OR=2.40, 95%CI: 1.50, 3.58)/quite often (OR=2.96, 95%CI: 1.73, 5.04; OR=2.72, 95%CI: 1.49, 4.94) maintaining a forced posture, and working immediately after break (OR=1.72, 95%CI: 1.04, 2.85; OR=2.14, 95%CI: 1.19, 3.88) were associated with a higher positive rate of neck pain and shoulder pain respectively. Feeling sufficient rest (OR=0.61, 95%CI: 0.47, 0.80; OR=0.63, 95%CI: 0.50, 0.83) and opportunity to decide when to take breaks (OR=0.72, 95%CI: 0.53, 0.98; OR=0.62, 95%CI: 0.41, 0.93) were associated with a lower positive rate of neck pain and shoulder pain respectively. Conclusion The positive rates of neck pain and shoulder pain are high among power distribution workers. The main influencing factors included long working age, quite often maintaining a forced posture, and working immediately after break.

Objective: To explore the prospective association between multidimensional sleep indicators and the risk of newlyonset dental caries, providing a reference for childrens oral healthrelated sleep intervention. Methods: In October 2021, 1 417 students in grades 1 to 4 (aged 6 to 11) from two elementary schools in Bengbu, Anhui Province, were selected by cluster sampling method. Surveys and followup visits were conducted at baseline (T1), November 2022 (T2), May 2023 (T3), and November 2023 (T4), respectively, including parental questionnaires, oral health and physical examination. Bedtime, sleep duration, sleep midpoint, social jet lag, weekend catchup sleep, and sleep habits were collected and calculated. A multifactorial Cox proportional risk regression model was used to analyze the association between multidimensional sleep indicators and newlyonset caries in schoolaged children after 2 years. Results: The prevalence of dental caries in children was 65.1% at baseline, and the prevalence was 59.0% at the end of the 2year followup. Cox proportional risk regression model showed that for every 1point increase in the childrens bedtime resistance, nocturnal awakenings, parasomnias, and daytime sleepiness scores, the risk of newlyonset caries increased by 12% (HR=1.12, 95%CI=1.08-1.15), 22% (HR=1.22, 95%CI=1.15-1.29), 12% (HR=1.12, 95%CI=1.08-1.17), and 15% (HR=1.15, 95%CI=1.12-1.19), respectively; the risk of newlyonset caries increased by 23% for each 1 h increase in the length of weekend catchup sleep (HR=1.23, 95%CI=1.14 -1.33); compared with children who went to bed before 21:00 on school days, those who went to bed later than 22:00 had a 57% higher risk of newlyonset caries (HR=1.57, 95%CI=1.22-2.03). Compared to children who slept adequately (≥9 h/d), those with insufficient sleep had a 67% higher risk of new caries (HR=1.67, 95%CI=1.43-1.95) (P<0.01). Conclusions These findings suggest a significant association between sleep patterns/sleep disorders and the development of childhood dental caries. Incorporating sleep behavior optimization and sleep quality improvement into comprehensive caries prevention and oral health management protocols may represent a promising intervention strategy to enhance childrens oral health outcomes.

Under the trend of increasing aging， integrated elderly care and medical services is an important measure to optimize the supply of elderly care services and promote the good death of the elderly. Using the cooperative production theory and the classical grounded theory， a qualitative analysis was conducted on 38 cases of elderly palliative care and 25 cases of hospital-based palliative care under the integrated elderly care and medical services model from a hospital in Nanning City using Nvivo 20.0 software. This paper found that the integrated elderly care and medical services mode emphasized the deep integration of medical and elderly care services by integrating resources and improving service efficiency， to achieve the basic experience of comprehensive health care for the elderly. The promotion of these experiences has a positive significance for building a multi-agent cooperative production system， strengthening personnel training， perfecting the performance distribution mechanism， and further promoting the development of the national palliative care pilot.

Objective: To understand classroom environmental conditions and their association with spinal curvature abnormalities among students of primary and secondary schools in Guizhou Province, so as to provide a basis for formulating school health policies and scientific prevention and control measures for abnormal spinal curvature in students. Methods: Using a stratified random sampling method, 471 schools (2 811 classrooms) were selected annually across the province from 2022 to 2024 in order to monitor and evaluate classroom environment according to national standards. Spinal examinations were conducted for 196 606 (2022), 194 876 (2023), and 195 048 (2024) students, and χ 2 test was used to analyze the correlation of desk and chair compliance with student spinal curvature abnormalities. Results: The qualified rates of classroom blackboard illuminance uniformity ( 85.41 %) and the blackboard size (82.24%) were the highest in primary and secondary schools in Guizhou Province, while the average blackboard surface illumination qualified rate (20.10%) was the lowest. The average desk illumination (50.11%-58.63%), desk illumination uniformity (61.92%-72.27%) and qualified noise rate (50.04%-51.94%) increased significantly in 3 years; in addition, the compliance rate of desks and chairs decreased from 25.00% to 13.52%, and the differences were all statistically significant ( χ 2=42.48, 80.93, 46.09, 129.72, all P <0.05). Middle school classrooms outperformed primary schools in terms of per capita area, average blackboard illuminance, blackboard illuminance uniformity, average desktop illuminance, desktop illuminance uniformity, and noise compliance ( χ 2=311.55, 12.41, 20.64, 40.76, 10.25, 52.47), but had lower compliance for blackboard size and reflectance ( χ 2=537.29, 7.59) (all P <0.01). Urban schools had higher compliance than suburban schools for per capita area, average blackboard illuminance, average desktop illuminance, and desktop illuminance uniformity ( χ 2=73.71, 17.68, 29.30 , 36.03), but lower compliance for desk-chair suitability, blackboard size, and blackboard reflectance ( χ 2=4.72, 26.02, 5.43 ) (all P <0.05). The spinal curvature abnormality detection rate was 0.83%. A significant association was found between abnormality detection and desk-chair non compliance ( χ 2=223.85, P <0.01). Conclusions Classroom environment hygiene in Guizhou schools is suboptimal. Strengthening school environmental hygiene infrastructure and greater attention to its impact on student s health are essential.

Objective: To understand the epidemiological characteristics of abnormalities spinal curvature among children and adolescents in Karst landform in Guizhou Province, so as to provide a scientific basis for targeted comprehensive intervention. Methods: From September to December 2023, 194 875 children and adolescents aged 6-18 were selected from all countieldistricts of 9 cities (prefectures) in Guizhou Province by stratified random cluster sampling method according to the proportion of Karst landform area in Guizhou Province for carrying out spinal curvature abnormality screening, and a questionnaire survey was conducted on 139 449 students in the fourth grade and above of primary school. Binary Logistic regression was used for multivariate analysis. Results: The detection rate of abnormal spinal curvature among children and adolescents aged 6-18 in Guizhou Province was 1.13%. The detection rates of abnormal spinal curvature in areas with a high proportion of Karst landform, areas with a low proportion of Karst landform, intercalation areas, and nonKarst landform areas were 1.10%, 2.00%, 0.90%, and 0.60%, respectively. Among them, the detection rates of abnormal spinal curvature in female students (2.40%, 1.60%, 0.90%) in areas with a low proportion of Karst landform, intercalation areas and nonKarst landform were higher than those in male students (1.60%, 0.10%, 0.30) (χ2=12.66, 112.69, 30.22, all P<0.05). The detection rates of abnormal spinal curvature among senior high school students (2.00%, 4.30%, 1.40%, 1.30%) in different Karst landform distributions were successively higher than those among junior high school students (1.40%, 3.20%, 1.00%, 0.60%) and primary school students (0.70%, 0.80%, 0.60%, 0.30%) (χ2=306.11, 175.80, 14.24, 39.57, all P<0.05). The results of multivariate Logistic regression analysis showed that the detection rates of abnormal spinal curvature in both highproportion and lowproportion Karst landform areas were higher than those in nonKarst landform areas [OR(95%CI)=1.84(1.05-2.25), 1.60(1.23-2.09), both P<0.05]. Conclusion The detection rate of abnormal spinal curvature in children and adolescents aged 6-18 in Guizhou Province is related to the distribution of Karst landform, so it is necessary to strengthen screening and appropriate comprehensive interventions.

ObjectiveTo systematically investigate the identification characteristics of medicinal amber， elucidate its microscopic features， crystal structural properties， and elemental composition， and thereby provide a scientific foundation for quality control and authenticity verification. MethodsThirty-nine batches of amber samples were collected and analyzed through integrated techniques including morphological analysis， microscopic identification， powder X-ray diffraction （XRD）， Raman spectroscopy， Fourier-transform infrared （FTIR） spectroscopy， and inductively coupled plasma mass spectrometry （ICP-MS） to evaluate their morphological attributes， phase composition， molecular vibrational modes， and trace element profiles. Among them， the XRD experiment used Cu Kα radiation （λ=1.540 6 Å）， with a scanning angle range of 10° to 70° （2θ） and a step size of 0.02°， the Raman spectroscopy experiment employed a 785 nm laser， with a spectral measurement range of 3 400 to 50 cm^-1， a laser power of 300 mW， a laser intensity of 30%， and a scanning time of 100 to 1 000 ms， the infrared spectroscopy experiment used a carbon-sulfur lamp， with a scanning range of 4 000 to 500 cm^-1， a resolution of 4 cm^-1， and 3 scans， the ICP-MS experiment utilized frequency power of 1.2 kW， a double-pass cyclonic spray chamber， a sample introduction system flow rate of 0.7-1.0 L·min^-1， and an auxiliary gas flow of 0.2 L·min^-1. ResultsUnder orthogonal polarized light microscopy， medicinal amber exhibited an isotropic homogeneous structure， with partial samples containing inorganic impurities such as AsS and SiO₂. FTIR spectra revealed characteristic absorption peaks at 2 932-2 939 cm^-1 （C-H stretching vibrations）， 1 705-1 728 cm^-1 （C=O stretching vibrations）， and 880-887 cm^-1 （C=C deformation vibrations）， confirming the oxidative polymerization of terpenoid resin. Raman spectroscopy further identified distinctive peaks at 2 925 cm^-1， 2 870 cm^-1 （saturated C-H stretching）， and 1 648 cm^-1 （C=C stretching）， consistent with the structural features of oxidized-polymerized resin. ICP-MS analysis demonstrated that S， Al， Si， Fe， Na， and Ca were the predominant trace elements in medicinal amber. ConclusionThis study comprehensively evaluated medicinal amber's morphological attributes， phase composition， molecular vibrational modes， and trace elements through multimodal analytical techniques. The findings establish data support for establishing quality standards for medicinal amber and distinguishing it from synthetic resin imitations.

ObjectiveTo systematically investigate the identification characteristics of medicinal amber， elucidate its microscopic features， crystal structural properties， and elemental composition， and thereby provide a scientific foundation for quality control and authenticity verification. MethodsThirty-nine batches of amber samples were collected and analyzed through integrated techniques including morphological analysis， microscopic identification， powder X-ray diffraction （XRD）， Raman spectroscopy， Fourier-transform infrared （FTIR） spectroscopy， and inductively coupled plasma mass spectrometry （ICP-MS） to evaluate their morphological attributes， phase composition， molecular vibrational modes， and trace element profiles. Among them， the XRD experiment used Cu Kα radiation （λ=1.540 6 Å）， with a scanning angle range of 10° to 70° （2θ） and a step size of 0.02°， the Raman spectroscopy experiment employed a 785 nm laser， with a spectral measurement range of 3 400 to 50 cm^-1， a laser power of 300 mW， a laser intensity of 30%， and a scanning time of 100 to 1 000 ms， the infrared spectroscopy experiment used a carbon-sulfur lamp， with a scanning range of 4 000 to 500 cm^-1， a resolution of 4 cm^-1， and 3 scans， the ICP-MS experiment utilized frequency power of 1.2 kW， a double-pass cyclonic spray chamber， a sample introduction system flow rate of 0.7-1.0 L·min^-1， and an auxiliary gas flow of 0.2 L·min^-1. ResultsUnder orthogonal polarized light microscopy， medicinal amber exhibited an isotropic homogeneous structure， with partial samples containing inorganic impurities such as AsS and SiO₂. FTIR spectra revealed characteristic absorption peaks at 2 932-2 939 cm^-1 （C-H stretching vibrations）， 1 705-1 728 cm^-1 （C=O stretching vibrations）， and 880-887 cm^-1 （C=C deformation vibrations）， confirming the oxidative polymerization of terpenoid resin. Raman spectroscopy further identified distinctive peaks at 2 925 cm^-1， 2 870 cm^-1 （saturated C-H stretching）， and 1 648 cm^-1 （C=C stretching）， consistent with the structural features of oxidized-polymerized resin. ICP-MS analysis demonstrated that S， Al， Si， Fe， Na， and Ca were the predominant trace elements in medicinal amber. ConclusionThis study comprehensively evaluated medicinal amber's morphological attributes， phase composition， molecular vibrational modes， and trace elements through multimodal analytical techniques. The findings establish data support for establishing quality standards for medicinal amber and distinguishing it from synthetic resin imitations.

Objective To explore the value of oral contrast-enhanced ultrasonography (OCEUS) combined with contrast-enhanced CT in predicting preoperative T staging in patients with gastric cancer. Methods A retrospective analysis was conducted on 80 patients with gastric cancer confirmed via endoscopic biopsy or postoperative pathology at the First People’s Hospital of Jining from January 2021 to November 2024. The cohort included 56 males and 24 females, aged 38-79 years, with a median age of 55.9 years. All patients underwent both OCEUS and contrast-enhanced CT within one week prior to surgery. T staging of gastric cancer was determined using OCEUS, contrast-enhanced CT, or their combination. The results were compared with pathological T staging, and statistical differences in accuracy were analyzed. Results Pathological T staging identified T1 in 9 cases, T2 in 16 cases, T3 in 42 cases, and T4 in 13 cases. OCEUS indicated T1 in 6 cases, T2 in 14 cases, T3 in 50 cases, and T4 in 10 cases, with an accuracy rate of 80.0%. Contrast-enhanced CT indicated T1 in 4 cases, T2 in 12 cases, T3 in 52 cases, and T4 in 12 cases, with an accuracy rate of 75.0%. The combination of OCEUS and contrast-enhanced CT indicated T1 in 6 cases, T2 in 15 cases, T3 in 47 cases, and T4 in 12 cases, with an accuracy rate of 87.5%. The combined approach demonstrated significantly higher accuracy in preoperative T staging compared to either method alone (P < 0.05). Conclusion The combination of OCEUS and contrast-enhanced CT improves the accuracy of preoperative T staging in gastric cancer patients, providing valuable support for their diagnosis and treatment.