Analysis and study on biomarkers of local muscle fatigue caused by repetitive lifting task.

BACKGROUND: Work-related musculoskeletal disorders (WMSDs) show a rapid growth trend. It has brought a huge economic burden to the society and become a serious occupational health problem that needs to be solved urgently. This study aimed to analyze the local muscle response under continuous ergonomic load, screen sensitive fatigue-related biomarkers and provide data support for the early prevention of local muscle damage and the exploration of early warning indicators. METHODS: Thirteen male college student volunteers were recruited to perform simulated repetitive manual lifting tasks in the laboratory. The lifting task was designed for 4 periods which lasted for 12 min in each, and then paused for 3 min for sampling. Local muscle fatigue is assesed by the Rating of perceived exertion (RPE) and the Joint analysis of sEMG spectrum and amplitude (JASA). Elbow venous blood was collected and 14 kinds of biomarkers were analyzed, which included Metabolic markers Ammonia (AMM), Lactic acid (LAC), Creatine kinase (CK), Lactate dehydrogenase (LDH), Cartilage oligomeric matrix protein (COMP), C-telopeptide of collagen I and II (CTX-I, CTX-II) and Calcium ion (Ca2+); Oxidative stress marker Glutathione (GSH); Inflammatory markers C-reaction protein (CRP), Prostaglandin E2 (PG-E2), Interleukin-6 (IL-6) and Tumor necrosis factor α (TNF-α); Pain marker Neuropeptide Y (NPY). Repeated measures analysis of variance (Repeated ANOVA), linear regression analysis, t-test and spearman correlation analysis were used to analyze the data. RESULTS: Both subjective and objective fatigue appeared at the same period. Serum AMM, LAC, CK, LDH, COMP, CTX-II, Ca2+ and NPY after fatigue were significantly higher than those before fatigue (p < 0.05). There was a certain degree of correlation between the markers with statistical differences before and after fatigue. CONCLUSIONS: Metabolic markers (serum AMM, LAC, CK, LDH, COMP, CTX-II, Ca2+) and pain markers (serum NPY) can reflect local muscle fatigue to a certain extent in repetitive manual lifting tasks. It is necessary to further expand the research on fatigue-related biomarkers in different types of subjects and jobs in the future.

The prevalence and risk factors of work related musculoskeletal disorders among electronics manufacturing workers: a cross-sectional analytical study in China.

OBJECTIVES: To describe the prevalence of self-reported musculoskeletal disorders among workers in the electronics manufacturing industry and to investigate the relations between work-related musculoskeletal disorders (WMSDs) and work-related variables. METHODS: An interview-based questionnaire survey was carried out in thirty electronics manufacturing factories in China in 2018. The prevalence of WMSDs was estimated using the modified Nordic Musculoskeletal Questionnaire (NMQ). A multivariate logistic regression model was applied to evaluate the effects of risk factors on WMSDs on multiple body parts. RESULTS: The 12-month prevalence of WMSDs among participants was 40.6%, and the common body sites affected were the neck (26.8%), shoulder (22.8%), upper back (14.9%), and lower back (14.8%). The results of logistic regression showed that female adults, > 5 job tenure and work-related factors (including awkward posture, lifting or carrying weights, excessive repetition, prolonged sitting, monotonous work and working under conditions of cold or temperature variations) led to a higher risk of WMSDs on most body parts. Upper back, wrist/hand and elbow pain levels were significantly higher for workers with vibration. However, more frequently, physical exercise was a protective factor against WMSDs on most body parts except the upper back, leg and knee. CONCLUSIONS: The study indicates a high prevalence of musculoskeletal pain among the electronics manufacturing industry in China. Different personal and work factors are related to the occurrence of WMSD on different body parts. Preventive measures should be implemented based on the characteristics of WMSD in the electronic manufacturing industry. Furthermore, the training and intervention guidance of ergonomic hazards in the workplace need to be strengthened by understanding the impact of bad posture, avoiding long-term sitting posture and increasing physical activities.

The association between adverse ergonomic factors and work-related musculoskeletal symptoms among medical staff in China: a cross-sectional study.

We investigated the prevalence of work-related musculoskeletal symptoms (WMSs) among medical staff and evaluated the associations of different levels of adverse ergonomic factors with WMSs. A total of 6099 Chinese medical staff were asked to complete a self-reported questionnaire to assess the prevalence and risk factors of WMSs from June 2018 to December 2020. A prevalence rate of 57.5% was observed for WMSs among overall medical staffs, which mainly affected the neck (41.7%) and shoulder (33.5%). 'Keeping sitting for long hours very frequently' (OR = 1.26, 95% CI: 1.04, 1.53) was positively associated with WMSs in doctors, while 'keeping sitting for long hours occasionally' (OR = 0.91, 95% CI: 0.85, 0.97) was identified as a protective factor of WMSs in nurses. The associations of adverse ergonomic factors, organisational factors, and environmental factors with WMSs were different among medical staff in different positions.Practitioner summary: We conducted a multi-city study concerning the risk factors of WMSs by carrying out a face-to-face one-to-multiple questionnaire survey among medical staff in China. As a risk factor of WMSs in medical staff, adverse ergonomic factors should be paid more attention by the standard setting department and policy makers.Abbreviations: WMSDs: work-related musculoskeletal disorders; WMSs: work-related musculoskeletal symptoms; MSDs: musculoskeletal disorders; NMQ: Nordic Musculoskeletal Questionnaires; DMQ: Dutch Musculoskeletal Questionnaires; NIOSH: National Institute for Occupational Safety and Health; ORs: odds ratios.

Prevalence and risk factors analysis for low back pain among occupational groups in key industries of China.

BACKGROUND: With the acceleration of industrialization and population aging, low back pain (LBP) has become the leading cause of life loss years caused by disability. Thus, it places a huge economic burden on society and is a global public health problem that needs urgent solution. This study aimed to conduct an epidemiological investigation and research on a large sample of workers in key industries in different regions of China, determine the incidence and distribution characteristics of LBP, explore the epidemic law, and provide a reference basis for alleviating global public health problems caused by LBP. METHODS: We adopted a modified epidemiological cross-sectional survey method and a stratified cluster sampling method. All on-duty workers who fulfill the inclusion criteria are taken as the research participants from the representative enterprises in key industries across seven regions: north, east, central, south, southwest, northwest, and northeast China. The Chinese version of the musculoskeletal disease questionnaire, modified by a standardized Nordic questionnaire, was used to collect information, and 57,501 valid questionnaires were received. Descriptive statistics were used, and multivariate logistic regression analysis (p < 0.05) was performed to explore the association between musculoskeletal disorders and potential risk factors. RESULTS: LBP annual incidence among workers in China's key industries is 16.4%. There was a significant difference in LBP incidence among occupational groups across different industries (p < 0.05). The multivariate regression model showed the following as risk factors for LBP: frequent repetitive movements with the trunk, working in the same positions at a high pace, trunk position, frequently turning around with your trunk, often working overtime, lifting heavy loads (i.e., more than 20 kg), education level, staff shortage, working age (years), cigarette smoking, use of vibration tools at work, body mass index, lifting heavy loads (i.e., more than 5 kg), and age (years). Physical exercise, often standing at work, and absolute resting time were protective factors. CONCLUSION: LBP incidence among key industries and workers in China is high. Thus, it is urgent to take relevant measures according to the individual, occupational, and psychosocial factors of LBP to reduce the adverse impact of LBP on workers' health.

Shoulder work-related musculoskeletal disorders and related factors of workers in 15 industries of China: a cross-sectional study.

BACKGROUND: Changes in modern industrial production practices can easily lead to shoulder work-related musculoskeletal disorders (WMSD). The current reports on shoulder WMSD are limited to some industries are less well studied, and the sample size is usually small. This study aimed to describe the prevalence and severity of shoulder WMSD in a large sample of Chinese workers from 15 industries, analyze the possible correlations with sociodemographic and work-related variables, and compare the differences between industries. METHODS: A cross-sectional study was conducted among a sample of 55,749 participants from 252 enterprises in 15 industries throughout China. A Chinese version of the musculoskeletal disease questionnaire was used to collect the demographic factors, shoulder symptoms in past 12 months, and work-related factors including posture-related factors, repetition, vibration, work organization, job control, and environmental factors as independent variables. Descriptive statistics were used, and the binary logistic regression analysis was performed to explore the association between shoulder WMSD and potential demographic and work-related factors. RESULTS: Nearly 35.5% of participants reported shoulder pain and discomfort in the previous 12 months. Biopharmaceutical manufacturing (56.2%), medical services (54.4%), and aviation services (50.1%) were the three industries with the highest prevalence of shoulder WMSD. The pain score of aviation services workers was the highest. The related factors for shoulder WMSD varied among the different industries. CONCLUSION: Our study found a relatively high prevalence of shoulder WMSD in China. There were large differences in the prevalence of shoulder WMSD among industries, and the related factors were particular to each industry. Such information is useful to help occupational health practitioners and policymakers conduct preventive programs to reduce shoulder disorders in these working populations.

Controlled 2H/1T phase transition in MoS2 monolayers by a strong interface with M2C MXenes: a computational study.

Due to the high conductivity and abundant active sites, the metallic 1T phase of a two-dimensional molybdenum sulfide monolayer (1T-MoS2) has witnessed a broad range of potential applications in catalysis, and spintronic and phase-switching devices, which, however, are greatly hampered by its poor stability. Thus, the development of particular strategies to realize the phase transition from the stable 2H phase to the metastable 1T phase for MoS2 nanosheets is highly desirable. Herein, by means of density functional theory (DFT) computations, we systematically explored the potential of the interfacial interaction of 2H- and 1T-MoS2 monolayers with a series of M2C MXenes (M = Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) for achieving the 2H/1T phase transformation. Our results revealed that the 2H → 1T transition for MoS2 monolayers can occur thermodynamically by anchoring on Ti2C, Zr2C, or Hf2C substrates with the extremely strong metal-S interaction, which can be well rationalized by the analysis of the charge transfer, work function, and density of states. Specially, these obtained stable 1T-MoS2/M2C hybrid materials exhibit excellent metallic features, outstanding magnetism, and enhanced mechanical properties. Our findings provide a new avenue to tune the phase transformation for MoS2 monolayers by strong interfacial interactions, which helps to further widen the potential applications of MoS2 monolayers.

Prevalence and risk factors for MSDs in vegetable greenhouse farmers: a cross-sectional survey from Shandong rural area, China.

PURPOSE: The aim of the research is a cross sectional survey on the prevalence of symptoms related to MSDs in vegetable greenhouse farmers from Shandong rural area and on the risk factors that may influence it. METHODS: This cross-sectional survey was selected 249 farmers working in vegetable greenhouse from different districts of Shandong Province, China. The Questionnaire and the Rapid Upper Limb Assessment (RULA) technique were used to identify ergonomic risks. χ2 analysis was used to find the relationship between MSDs and various factors. Also, logistic regression methodology was applied to get the most influencing factor for MSDs. RESULTS: The prevalence of MSDs in farmers working in vegetable greenhouse is 87.5%, and the top 3 prevalent areas of MSDs in various parts of the body are: lower back (47.4%), neck (33.3%), and shoulder (31.7%). The results of Logistic regression analysis showed that age, years working in vegetable greenhouses, keeping their backs in the same position for a long time, and working hours greater than 10 hours per day were the risk factors for MSDs in the farmers. The outcome of the RULA grand score had been found to be higher than 5 in the overwhelming majority of the farmers. CONCLUSIONS: All findings infer that each task of greenhouse vegetable growing inflicts different levels of disorder in a farmers' musculoskeletal structure. Interventions should be increased and reduce the bad ergonomic load level as soon as possible, provided to reduce the impact of such disorders.

Tuning the electronic structures of monolayer triphosphides MP3 (M = Sn and Ge) for CO2 electroreduction through interface engineering: a theoretical prediction.

Interface engineering by integrating various two-dimensional materials to form heterostructures can not only preserve the desired properties of individual components, but also induce new functions. Herein, by means of density functional theory (DFT) computations, we have investigated the effects of interface engineering of the graphene substrate on the electronic structures of monolayer triphosphides MP3 (M = Sn and Ge) and their catalytic performance for the electroreduction of carbon dioxide (CO2ER). Our results revealed that the MP3/graphene interfaces exhibit good structural stability, enhanced electrical conductivity, superior CO2ER performance, and obvious suppressing effects on hydrogen evolution due to the charge transfer at the interface. Thus, our results suggested that SnP3/graphene and GeP3/graphene heterostructures can be utilized as promising CO2ER catalysts with high-efficiency and high-selectivity, offering cost-effective opportunities to convert CO2 for renewable energy supply via interface engineering.

Computational screening of a single transition metal atom supported on the C2N monolayer for electrochemical ammonia synthesis.

The nitrogen reduction reaction (NRR) under ambient conditions using renewable energy is a green and sustainable strategy for the synthesis of NH3, which is one of the most important chemicals and carbon-free carriers. Thus, the search for low-cost, highly efficient, and stable NRR electrocatalysts is critical to achieve this goal. Herein, using comprehensive density functional theory (DFT) computations, we design a new class of NRR electrocatalysts based on a single transition metal (TM) atom supported on the experimentally feasible two-dimensional C2N monolayer (TM@C2N). Based on the computed free energies of each elementary pathway, Mo@C2N is predicted to exhibit the best catalytic activity among the TM@C2N, in which the proton-coupled electron transfer of the NH2* species to NH3(g) is the potential-determining step. Especially, the computed onset potential of the NRR on Mo@C2N is -0.17 V, which is even lower than that for the well-established stepped Ru(0001) surface (-0.43 V). Furthermore, the NRR catalytic performance of these TM@C2N can be well explained by their adsorption strength with N2H* species. Our findings open a new avenue for optimizing the TM catalytic performance for the NRR with the lowest number of metal atoms on porous low-dimensional materials.

CO2 electroreduction performance of a single transition metal atom supported on porphyrin-like graphene: a computational study.

Searching for low-cost, efficient, and stable electrocatalysts for CO2 electroreduction (CO2ER) reactions is highly desirable for the reduction of CO2 emission and its conversion into useful products, but remains a great challenge. In this work, single transition metal atoms supported on porphyrin-like graphene catalysts, i.e., TMN4/graphene, acting as electrocatalysts for CO2 reduction were explored by means of comprehensive density functional theory (DFT) computations. Our results revealed that these anchored TM atoms possess high stability due to their strong hybridization with the unsaturated N atoms of the substrate and function as the active sites. On the basis of the calculated adsorption strength of CO2ER intermediates, we have identified that single Co, Rh, and Ir atoms exhibit superior catalytic activity towards CO2 reduction. In particular, CH3OH is the preferred product of CO2ER on the CoN4/graphene catalyst with an overpotential of 0.59 V, while the RhN4/graphene and IrN4/graphene catalysts prefer to reduce CO2 to CH2O with an overpotential of 0.35 and 0.29 V, respectively. Our work may open a new avenue for the development of catalytic materials with high efficiency for CO2 electroreduction.

[Toxicity of vehicle exhaust on BEAS-2B cells in vitro by air-liquid interface].

OBJECTIVE: To evaluate the toxic effect of vehicle exhaust( VE) on lung epithelial cells by air-liquid interface( ALI) method in vitro, and analyze the different toxicity of VE after being treated with 0. 2 µm filter. METHODS: VE were collected using20 liter Tedlar bags and their particulate matter( PM) number, surface and mass concentration were measured by particle size spectrometer for the interference of 0. 2 µm filter or non-filter. Four groups were included, which divided into blank control group, clean air group, filtered VE exposure group, non-filtered VE exposure group. The blank control group did not do any treatment; the clean air group was an artificial gas containing21% O_2 and 79% N_2; the filtered VE group( marked as f VE) was filtered using a 0. 2µm particle filter for VE. The VE group was used VE directly collected by air bag and marked as non-f VE. Except the blank control group, BEAS-2B cells were treated with clean air or VE by ALI method at a flow rate of 25 mL/min, 37 ℃ for 60 min in vitro. Cell relative viability was evaluated by CCK-8 assay. The reactive oxygen species( ROS)generation was determined via flow cytometry with 2', 7'-dichloro-dihydro-fluorescein diacetate( DCFH-DA) probe. Apoptosis and necrosis rate were measured using the commercial kit of Annexin V-FITC/PI by flow cytometry. RESULTS: In the non-f VE group, the PM of number, surface and mass concentration for 0. 5-10 µm diameters were 0. 24×10~3N/cm~3, 0. 29 ×10~3µm~2/cm~3 and 0. 19 µg/m~3, respectively, and for the PM of 10-500 nm diameters, they were 56 ×10~3N/cm~3、34. 53 ×10~8nm~2/cm~3 and 95ng/m~3, respectively. The PM of 0. 5-10 µm diameters in f VE group, their number, surface and mass concentration were less than 1 N/cm~3, 1 µm~2/cm~3 0. 001 µg/m~3, respectively. After filtration, the number, surface and mass concentration of PM in 10-500 nm diameters reduced by 89. 79%, 93. 57% and 90. 55%, respectively, as compared with non-f VE. In the clean air group, the cell relative viability, ROS generation, early apoptosis rate and late apoptosis and necrosis rate were( 90. 15 ± 4. 25) %, ( 1. 92 ± 0. 34)×10~5, ( 1. 09 ± 0. 48) % and( 8. 93 ± 3. 31) %, respectively. Compared with the clean air group, the cell relative viability, the ROS generation and the late apoptosis and necrosis rate of the two VE exposure groups were significantly different( all P < 0. 05). The cell relative viability of f VE exposure group were significantly higher than that in the non-f VE exposure group( t = 6. 331, P < 0. 001), and had no significant difference about the ROS generation[f VE ∶ non-VE =( 2. 94 ± 0. 21) ×10~5∶( 3. 32 ± 0. 49) ×10~5, t =-1. 252, P = 0. 279], early apoptosis rate [f VE∶ non-VE =( 1. 09 ± 0. 30) % ∶( 0. 99 ±0. 10) %, t = 0. 708, P = 0. 497] and late apoptosis and necrosis rate [f VE ∶ non-VE =( 21. 75 ± 10. 37) % ∶( 15. 32 ± 2. 74) %, t = 1. 347, P = 0. 242] between f VE and nonf VE exposure group( all P > 0. 05). CONCLUSION: Increased toxicity of human lung cells( BEAS-2B) in vitro were observed by ALI method at a flow rate of 25 mL/min, 37 ℃ for60 min. After using a 0. 2 µm filter, the toxicity was obviously decreased.

Prevalence and its risk factors for low back pain among operation and maintenance personnel in wind farms.

BACKGROUND: With the increasingly severe energy shortage and climate change problems, developing wind power has become a key energy development strategy and an inevitable choice to protect the ecological environment worldwide. The purpose of this study was to investigate the prevalence of low back pain (LBP) and analyze its risk factors among operation and maintenance personnel in wind farms (OMPWF). METHODS: A cross-sectional survey of 151 OMPWF was performed, and a comprehensive questionnaire, which was modified and combined from Nordic Musculoskeletal Questionnaires (NMQ), Washington State Ergonomics Tool (WSET) and Syndrome Checklist-90(SCL-90) was used to assess the prevalence and risk factors of LBP among OMPWF. RESULTS: The prevalence of LBP was 88.74 % (134/151) among OMPWF. The multivariable model highlighted four related factors: backrest, somatization, squatting and lifting objects weighing more than 10 lb more than twice per minute. CONCLUSIONS: The prevalence of LBP among OMPWF appears to be high and highlights a major occupational health concern.

[Present state of occupational hazards in automobile maintenance industry in Beijing, China].

OBJECTIVE: To explore the present state of occupational hazards and health status of workers in the automobile maintenance industry. METHODS: The monitoring results of occupational hazards in 25 automobile maintenance companies, occupational health examination results of 751 male workers in 63 automobile maintenance companies, and physical examination results of 205 male students in one Research Institute were statistically analyzed in 2012. RESULTS: The concentrations of benzene, toluene, xylene, ethyl acetate, and butyl acetate in the workplace were 0.3∼21.7, 0.4∼40.3, 0.4∼84.8, 1.9∼34.3, and 0.7∼516.7 mg/m(3), respectively; benzene concentration exceeded the upper limit in two workplaces, and butyl acetate concentration exceeded the upper limit in one workplace. The intensity of noise was 70.3∼ 91.3 dB (A) and exceeded the upper limit in one workplace. The prevalence of blood system involvement in spray painters was 15.6%, significant higher than that of the control group (P < 0.05). High-frequency hearing loss was detected in 53.9%of all metalers. Logistic regression analysis indicated that blood system involvement was not correlated with age and working years in spray painters; high-frequency hearing loss in metalers was positively correlated with age, but not correlated with working years. CONCLUSION: The status of occupational hazards in the automobile maintenance industry should not be neglected, and the management of noxious positions and personal protection should be strengthened in enterprises.

Effects of Simulated Acid Rain on Photosynthesis in Pinus massoniana and Cunninghamia lanceolata in Terms of Prompt Fluorescence, Delayed Fluorescence, and Modulated Reflection at 820 nm.

The effects of simulated acid rain (SAR) on the photosynthetic performance of subtropical coniferous species have not been thoroughly investigated. In this study, we treated two coniferous species, Pinus massoniana (PM) and Cunninghamia lanceolata (CL), with four gradients of SAR and then analyzed their photosynthetic activities through measurements of gas exchange, prompt fluorescence (PF), delayed fluorescence (DF), and modulated reflection at 820 nm (MR820). Gas exchange analysis indicated that the decrease in the net photosynthetic rate (Pn) in PM and CL was unrelated to stomatal factors. For the PF transients, SAR induced positive K-band and L-band, a significant reduction in photosynthetic performance index (PIABS), the quantum yield of electron transfer per unit cross-section (ETO/CSm), and maximal photochemical efficiency of photosystem II (Fv/Fm). Analysis of the MR820 kinetics showed that the re-reduction kinetics of PSI reaction center (P700+) and plastocyanin (PC+) became slower and occurred at later times under SAR treatment. For the DF signals, a decrease in the amplitude of the DF induction curve reduced the maximum value of DF (I1). These results suggested that SAR obstructed photosystem II (PSII) donor-side and acceptor-side electron transfer capacity, impaired the connectivity between PSII and PSI, and destroyed the oxygen-evolving complex (OEC). However, PM was better able to withstand SAR stress than CL, likely because of the activation of a protective mechanism.

Epidemiological study of multi-site WMSDs in the footwear industry in China.

Objectives. This study aimed to identify the prevalence of multi-site work-related musculoskeletal disorders (WMSDs) in Chinese footwear industry workers from 2018 to 2020 and explore the possible influencing factors of WMSDs. Methods. 7106 subjects from 26 large shoe factories in China were investigated using the epidemiological cross-sectional survey method by using the Nordic musculoskeletal questionnaire (NMQ). Results. The total prevalence of WMSDs in the study subjects was 36.8% (2616/7106). Among them, the prevalence of multi-site WMSDs was 26.1% (1858/7106). The proportion of multi-site WMSDs involving two sites was the largest (31.38%). In addition, the results showed that the risk factors of multi-site WMSDs were gender, marital status, long current job experience, poor health, poor working posture, etc. Conclusions. The prevalence of WMSDs was high in the Chinese footwear industry. Based on the results, therefore, it seems necessary to improve work posture, work organization and workenvironment to prevent WMSDs.

α-Ketoglutarate Improves Ovarian Reserve Function in Primary Ovarian Insufficiency by Inhibiting NLRP3-Mediated Pyroptosis of Granulosa Cells.

SCOPE: Premature ovarian insufficiency (POI) is a common female infertility problem, with its pathogenesis remains unknown. The NOD-like receptor family pyrin domain-containing 3 (NLRP3)-mediated pyroptosis has been proposed as a possible mechanism in POI. This study investigates the therapeutic effect of α-ketoglutarate (AKG) on ovarian reserve function in POI rats and further explores the potential molecular mechanisms. METHODS AND RESULTS: POI rats are caused by administration of cyclophosphamide (CTX) to determine whether AKG has a protective effect. AKG treatment increases the ovarian index, maintains both serum hormone levels and follicle number, and improves the ovarian reserve function in POI rats, as evidence by increased the level of lactate and the expression of rate-limiting enzymes of glycolysis in the ovaries, additionally reduced the expression of NLRP3, Gasdermin D (GSDMD), Caspase-1, Interleukin-18 (IL-18), and Interleukin-1 beta (IL-1ß). In vitro, KGN cells are treated with LPS and nigericin to mimic pyroptosis, then treated with AKG and MCC950. AKG inhibits inflammatory and pyroptosis factors such as NLRP3, restores the glycolysis process in vitro, meanwhile inhibition of NLRP3 has the same effect. CONCLUSION: AKG ameliorates CTX-induced POI by inhibiting NLRP3-mediated pyroptosis, which provides a new therapeutic strategy and drug target for clinical POI patients.

Risk and related factors of elbow musculoskeletal diseases: a nationwide cross-sectional survey in China.

OBJECTIVES: Although studies have shown that work-related musculoskeletal disorders (WMSDs) are common and continue to be a major source of disability and work time loss, there are few reports about elbow WMSDs. The aim of this study was to explore the prevalence and associated factors of elbow WMSDs. METHODS: The valid questionnaires of 57501 workers from 15 different industries nationwide were collected and the c2 test and logistic regression analysis were applied to reveal the prevalence and risk factors of elbow WMSDs. RESULTS: The findings indicated that the overall prevalence of elbow WMSDs among workers was 7.3%. However, the prevalence of elbow WMSDs in toy manufacturing was 21.3%, which was significantly higher than that in other industries (P < .05). Logistic regression analysis showed that age 40 and above, married, very poor health, left-handedness, lifting weights (more than 20 kg each time), work requiring upper limb or hand force, work in an uncomfortable position, repetitive operations within 1 minute, using vibrating tools, work involving cold, cool draughts, or temperature changes, work being completed in the same workshop, work being done outdoors, frequent dealings with customers, 2 shifts, often working overtime, staff shortage, and often working for colleagues were risk factors for elbow WMSDs. A higer education level, monthly income, and enough rest time were protective factors for elbow WMSDs. CONCLUSIONS: Toy manufacturing is a high-risk industry for elbow WMSDs. Promotion of education about ergonomics should be strengthened, and workers' ergonomics awareness should be improved to reduce the impact of WMSDs.

Interface engineering of transition metal-nitrogen-carbon by graphdiyne for boosting the oxygen reduction/evolution reactions: A computational study.

Exploring high-efficiency electrocatalysts to boost the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is pivotal to the large-scale applications for clean and renewable energy technologies, such as fuel cells, water splitting, and metal-air batteries. Herein, by means of density functional theory (DFT) computations, we proposed a strategy to modulate the catalytic activity of transition metal-nitrogen-carbon catalysts through their interface engineering with graphdiyne (TMNC/GDY). Our results revealed that these hybrid structures exhibit good stability and excellent electrical conductivity. Especially, CoNC/GDY was identified as a promising bifunctional catalyst for ORR/OER with rather low overpotentials in acidic conditions according to the constant-potential energy analysis. Moreover, the volcano plots were established to describe the activity trend of the ORR/OER on TMNC/GDY using the adsorption strength of the oxygenated intermediates. Remarkably, the d-band center and charge transfer of the TM active sites can be utilized to correlate the ORR/OER catalytic activity and their electronic properties. Our findings not only suggested an ideal bifunctional oxygen electrocatalyst, but also provided a useful strategy to obtain highly efficient catalysts by interface engineering of two-dimensional heterostructures.

Machine-learning-accelerated screening of single metal atoms anchored on MnPS3 monolayers as promising bifunctional oxygen electrocatalysts.

Searching for bifunctional oxygen electrocatalysts with good catalytic performance to promote the oxygen evolution/reduction reactions (OER/ORR) is of great significance to the development of sustainable and renewable clean energy. Herein, we performed density functional theory (DFT) and machine-learning (DFT-ML) hybrid computations to investigate the potential of a series of single transition metal atoms anchored on the experimentally available MnPS3 monolayer (TM/MnPS3) as the bifunctional electrocatalysts for the ORR/OER. The results revealed that the interactions of these metal atoms with MnPS3 are rather strong, thus guaranteeing their high stability for practical applications. Remarkably, the highly efficient ORR/OER can be achieved on Rh/MnPS3 and Ni/MnPS3 with lower overpotentials than those of metal benchmarks, which can be further rationalized by establishing the volcano and contour plots. Furthermore, the ML results showed that the bond length of TM atoms with the adsorbed O species (dTM-O), the number of d electrons (Ne), the d-center (εd), the radius (rTM) and the first ionization energy (Im) of the TM atoms are the primary descriptors featuring the adsorption behavior. Our findings not only suggest novel highly efficient bifunctional oxygen electrocatalysts, but also provide cost-effective opportunities for the design of single-atom catalysts using the DFT-ML hybrid method.

Review on Main Gate Characteristics of P-Type GaN Gate High-Electron-Mobility Transistors.

As wide bandgap semiconductors, gallium nitride (GaN) lateral high-electron-mobility transistors (HEMTs) possess high breakdown voltage, low resistance and high frequency performance. PGaN gate HEMTs are promising candidates for high-voltage, high-power applications due to the normally off operation and robust gate reliability. However, the threshold and gate-breakdown voltages are relatively low compared with Si-based and SiC-based power MOSFETs. The epitaxial layers and device structures were optimized to enhance the main characteristics of pGaN HEMTs. In this work, various methods to improve threshold and gate-breakdown voltages are presented, such as the top-layer optimization of the pGaN cap, hole-concentration enhancement, the low-work-function gate electrode, and the MIS-type pGaN gate. The discussion of the main gate characteristic enhancement of p-type GaN gate HEMTs would accelerate the development of GaN power electronics to some extent.