Determination and analysis of monitoring period and measuring duration of personal internal exposure dose / 中国辐射卫生

Objective To develop a reasonable plan of monitoring personal internal exposure dose. Methods This paper introduced the methods of monitoring the individual dose and direct measurement of three representative radionuclides. Results The maximum monitoring periods were determined according to the radionuclide retention characteristics and the reporting standards and requirements, which were m(1)/m(T/2) ≤ 3 and m(T/2)/m(T) ≤ 3. The lower detection limit of the instrument was derived from the monitoring periods and the annual radionuclide intake limit, which should be lower than the derived method detection limit of the corresponding radionuclide. Then the measuring duration of the instrument that meets the corresponding conditions was derived from the derived method detection limit of the instrument and the maximum monitoring period. Conclusion Our results provide a reference for the formulation of a plan of monitoring personal internal exposure dose.

Research progress on immunotherapy for triple-negative breast cancer / 中国临床药理学与治疗学

Triple-negative breast cancer (TNBC) is a subtype of breast cancer characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). It is highly aggressive, easy to relapse, and chemotherapy remains its mainstay treatment due to the lack of therapeutic targets. In recent years, many advances have been made in the development of immunotherapy for TNBC. This review summarizes the primary modalities of immunotherapy for TNBC, including immune checkpoint inhibitors, adoptive immune cell therapy, tumor vaccines and oncolytic virus. We present the latest research progress on each treatment from the perspective of clinical study and fundamental research, while introducing the potential predictive biomarkers and resistance mechanisms of immunotherapy for TNBC.

The interaction between social psychology and workload factors of neck work-related musculoskeletal disorders / 中国职业医学

{L-End}Objective To explore the interaction between social psychology and workload factors on neck work-related musculoskeletal disorders (WMSDs) in manual workers. {L-End}Methods Manual workers in Henan Province and Hubei Province were selected as the research subjects using typical sampling method. The Chinese Musculoskeletal Questionnaire was used to investigate the prevalence of neck WMSDs in the research subjects. A total of 4 327 workers with neck WMSDs were selected as the case group, and 4 327 workers without neck WMSDs were selected as the control group in a 1∶1 pairing. Conditional logistic regression analysis was used to compare the relevant risk factors in the two groups, and the additive interaction model was established to analyze the interactions between the risk factors. {L-End}Results The univariate conditional logistic analysis results showed that dynamic load, static load, power load and psychosocial factors increased the risk of neck WMSDs in manual workers (all P<0.05). In terms of the social psychological factors, insufficient rest time had the greatest impact workers, with the odds ratio (OR) and 95% confidence interval (CI) of 1.799 (1.647-1.965). In terms of dynamic load, static load and power load, repeated similar movements of the head per minute (bending, twisting), forward bending of the neck or maintaining this posture for a long time, and lifting heavy objects>20 kg had the greatest impact, with the OR and 95%CI of 1.599 (1.470-1.739), 1.984 (1.805-2.181) and 1.241 (1.093-1.408), respectively. There was a synergistic interaction between insufficient rest time and forward bending of the neck or maintaining this posture for a long time, and the relative excess risk due to interaction (95%CI) and attributable proportion (95%CI) were 0.420 (0.187-0.652) and 0.171 (0.066-0.276), respectively. There is no interaction between insufficient rest time and repeated similar movements of the head per minute (bending, twisting), and lifting heavy objects >20 kg. {L-End}Conclusion The interaction between insufficient rest time and forward bending of the neck or maintaining this posture for a long time (static load) can increase the risk of neck WMSDs in manual workers, which is an additive synergistic effect.

Study on influencing factors of work-related musculoskeletal disorders in neck-shoulder-back of manufacturing workers / 中国职业医学

{L-End}Objective To investigate the influencing factors of work-related musculoskeletal disorders (WMSDs) that affect neck-shoulder-back among manufacturing workers. {L-End}Methods A total of 8 250 front-line workers from 27 manufacturing enterprises in Henan Province and Hubei Province were selected as the research subjects using cluster sampling method. The Musculoskeletal Disorders Questionnaire was used to investigate the prevalence of neck-shoulder-back (include neck, shoulder, upper back, and lower back) WMSDs in the past year. The log-binomial model, principal component analysis (PCA) and multivariate logistic regression analysis were used to analyze the influencing factors of WMSDs in the neck-shoulder-back. {L-End}Results The prevalence of WMSDs was 77.2%. The prevalence of neck-shoulder-back WMSDs was 50.9%. The prevalence ratios of WMSDs were relatively higher among the neck, shoulder, and upper back (all P<0.05). The results of PCA improved logistic regression analysis showed that the influencing factors of neck-shoulder-back WMSDs were individual factors, biomechanical factors, psychosocial factors and environmental factors. In terms of individual factors, the risk of neck-shoulder-back WMSDs was higher in females than in males (P<0.05). With the increase of age, length of service, and education level, the risk of neck-shoulder-back WMSDs increased among manufacturing workers (all P<0.05). The risk of neck-shoulder-back WMSDs of workers in textile, clothing, shoes and hats manufacturing industry was relatively lower than that in the other nine industries (all P<0.05). In terms of the biomechanical factors, spending a lot of effort to operate tools/machines, sitting for a long time at work,bending greatly bending and turning at the same time, neck leaning forward or maintaining this posture for a long time, neck twisting or maintaining this posture for a long time and uncomfortable position resulting in difficulty exerting exertion were all risk factors of neck-shoulder-back WMSDs among manufacturing workers (all P<0.05) Bending slightly for a long time was a protective factor for neck-shoulder-back WMSDs among manufacturing workers (P<0.05). In terms of the psychosocial factors, doing the same work every day, self-determination in resting time between works staff shortage, and frequent overtime work were risk factors for neck-shoulder-back WMSDs among manufacturing workers (all P<0.05). Adequate resting time was a protective factor for neck-shoulder-back WMSDs among manufacturing workers (P<0.01). In terms of environmental factors, working under cold or fluctuating temperature, having nothings to lean on, and soles slipping or falling at work were all risk factors for neck-shoulder-back WMSDs among manufacturing workers (all P<0.05). {L-End}Conclusion Manufacturing workers are prone to suffer from neck-shoulder-back WMSDs. The influencing factors include individual factors, biomechanical factors (force load and static load), psychosocial factors and environmental factors.

Overview of advances in evaluation methods for ergonomic exposure / 环境与职业医学

Ergonomic exposure is one of the important causes of work-related musculoskeletal disorders (WMSDs). Accurate measurement and evaluation of ergonomic exposure level and implementation of ergonomic intervention are of great significance to the prevention and control of WMSDs. Ergonomic exposure can be divided into external exposure and internal exposure, and its evaluation methods include subjective judgment method, systematic observation method, and direct measurement method. This paper summarized the internal exposure assessment methods based on musculoskeletal dynamics and biomarkers, introduced the overall design concept of ergonomic exposure assessment system, used the Ergonomic Assessment Worksheet (EAWS) as an example, and discussed the development trend of automation, intelligence, and compounding of ergonomic exposure assessment methods and the factors considered in the selection of ergonomic exposure assessment methods.

Study on ergonomic intervention to relieve work-related musculoskeletal disorders among assembly workers in a railway vehicle manufacturing enterprise / 环境与职业医学

Background Work-related musculoskeletal diseases (WMSDs) occur in a variety of occupational populations. Because of their various discomfort and serious disease burden, they have become an important issue worthy of attention in the field of occupational health. The prevention and control of WMSDs is one of the public health problems to be solved. Objective To evaluate the intervention effect on WMSDs among assembly workers in a railway vehicle manufacturing enterprise, so as to provide scientific basis for the prevention and control of WMSDs. Methods A total of 250 assembly workers in a railway vehicle manufacturing enterprise were selected using convenience sampling from August to December 2017. The Chinese Musculoskeletal Questionnaire was used for epidemiological investigation, and the Ergonomic Checkpoints was used for ergonomic inspection and worker interview. According to the above survey results, a six-month intervention plan including stepladder improvement and ergonomics training were implemented in the assembly workshop from September 2018 to February 2019. The intervention effects including the awareness of WMSDs, the exposure level of ergonomic load, and the occurrence of WMSDs symptoms were evaluated with relevant cross-sectional survey results before and after the intervention. The scores of WMSDs symptom intensity, symptom duration, and symptom frequency from low to high were 0-10, 1-4, and 1-5, respectively. Results After the intervention, the awareness rates of assembly workers on WMSDs types, affected body sites, influencing factors, preventive measures, and symptoms all increased from 52.3%, 51.9%, 25.5%, 19.1%, and 51.5% to 68.5%, 61.3%, 48.1%, 40.9%, and 61.3%, respectively (P<0.05). After the intervention, the proportion of assembly workers who "often" bend their head backwards frequently decreased from 34.6% to 21.8%, the proportion who "often" keep their trunk backward for a long time decreased from 26.6% to 15.0%, and the proportion who "never" raise their arms frequently increased from 3.4% to 9.0% (P<0.05). After the intervention, the scores of WMSDs symptom intensity in neck, shoulders, upper back, low back, elbows, hands/wrists, hips/thighs, knees, and ankles/feet all decreased, and the medians were mostly decreased from 6 to 3 (P<0.05); the scores of WMSDs symptom duration only decreased in neck (P<0.05) and there was no significant difference in the other body sites before and after the intervention; the median scores of WMSDs symptom frequency in low back, hands/wrists, and hips/thighs decreased from 3 to 2 (P<0.05). Conclusion The six-month intervention of stepladder improvement and ergonomics training among assembly workers in a railway vehicle manufacturing enterprise can improve workers' awareness of WMSDs, and reduce the exposure frequency of awkward postures and the intensity, duration, and frequency of WMSDs symptoms.

Relationship between ergonomic exposures and work-related musculoskeletal disorders of assembly workers in assembly manufacturing enterprises / 环境与职业医学

Background China's manufacturing industry is still labor-intensive, and assembly employees in manufacturing industry are facing a great risk of work-related musculoskeletal disorders (WMSDs). Objective To investigate and analyze the prevalence and distribution of WMSDs among assembly workers in manufacturing enterprises and explore the relationship between WMSDs and ergonomic exposure factors such as posture load and mental load. Methods From July to September 2017, by convenient sampling, a cross-sectional survey was conducted to select 670 workers engaged in electronic accessories assembly and railway vehicle manufacturing in three manufacturing enterprises in two cities in northern China as the research participants. The posture load assessment was based on the Chinese Musculoskeletal Questionnaire independently developed by our research group. The mental load assessment was based on a revised Chinese version of the Subjective Workload Assessment Technique. An unconditional logistic regression model was used to explore the relationship between ergonomic exposure and WMSDs. Results The overall prevalence rate of WMSDs was 39.6% (265/670) with 43.8% in males and 25.2% in females; the highest prevalence rate was 47.7% in the group aged 40 years and over. The prevalence rate of WMSDs in the electronic accessories assembly workers was 16.9%, that in the railway vehicle manufacturing workers was 57.3%, and the difference was statistically significant (\begin{document}$ {\chi

Influencing factors for work-related musculoskeletal disorders among assembly workers in four manufacturing enterprises / 环境与职业医学

Background The prevalence rate of work-related musculoskeletal disorders (WMSDs) among manufacturing workers is relatively high and has been widely concerned. However, research on the prevalence and risk factors of multi-site WMSDs is still insufficient. Objective To explore the prevalence and risk factors of multi-site WMSDs of assembly workers in four manufacturing enterprises. Methods The "Chinese Musculoskeletal Questionnaire" was used to conduct a cross-sectional survey among 1401 assembly workers selected by convenient sampling in four manufacturing enterprises, and their demographic characteristics, the prevalence of WMSDs in various body parts, and the information about biomechanical factors, work organizations, work environment, and psychosocial factor exposure were collected. The prevalence of WMSDs and multi-site WMSDs were estimated, Pearson χ2 test was used for univariate analysis of multi-site WMSDs risk factors, and logistic regression was used for multi-factor analysis. Results The total prevalence rate of WMSDs was 54.9% (769/1 401). The top three affected sites were neck (41.4%), shoulders (30.7%), and wrist/hand (25.1%). The prevalence rate of multi-site WMSDs was 41.9% (587/1 401). The prevalence rates of multi-site WMSDs in railway vehicle assembly and riveting workers were higher than those in electronic parts processing and glass manufacturing workers (P<0.001). The results of logistic regression analysis showed that individual factors such as female (OR=2.09, 95%CI: 1.48−2.97) and drinking (OR=1.52, 95%CI: 1.05−2.18), biomechanics factors such as keeping head down for a long time (OR=1.37, 95%CI: 1.22–1.53), keeping bending frequently (OR=1.18, 95%CI: 1.03–1.34), and keeping arms up for a long time (OR=1.25, 95%CI: 1.10–1.41), work organizational factors such as electronic parts processing, railway vehicle assembly, and riveting (OR values were 3.23, 5.70, and 13.83, respectively), environmental factors such as temperature a little cold (OR=4.84, 95%CI: 1.90–12.37), noise seriously affecting work (OR=2.25, 95%CI: 1.23–4.11), and psychosocial factors such as high job demands (OR=1.47, 95%CI: 1.04–2.08), fatigue after work (OR=1.92−2.61) were risk factors of multi-site WMSDs. Conclusion The prevalence rate of multi-site WMSDs in assembly workers is high, and the main influencing factors include individual factors, awkward work postures, environmental factors, and psychosocial factors.

Pay attention to the prevention and control of work-related musculoskeletal disorder / 环境与职业医学

The health impacts and economic burdens associated by work-related musculoskeletal disorders (WMSDs) have become an important issue in the field of occupational health. Compared with developed countries, we should more systematically carry out in-depth research and practice on occupational ergonomics, comprehensively understand ergonomic factors and their characteristics, and strengthen the intervention and health risk assessment of ergonomic risk factors in key workplaces based on specific production conditions of different industries, so as to prevent and control the occurrence and development of WMSDs. This article introduced the concept, signs, symptoms, risk factors, and currently identifiable site-specific WMSDs. This column presented new research progress from the aspects of ergonomic load assessment methods, the prevalence and related risk factors of WMSDs in different trades, and ergonomic intervention of WMSDs, aiming to provide reference and basis for future research.

Usage of printing equipment in college teachers' offices and influencing factors of released particulate matter / 环境与职业医学

Background Printing and copying equipment is likely to release a large amount of particulate matter, thereby endangering human health. However, there is insufficient research on the level of particulate matter released by printers in offices and its influencing factors. Objective This study is designed to investigate the usage of printing equipment in college teachers' offices and the level of indoor particulate matter during printing, and to explore the influence of printer location and indoor ventilation on the particulate matter pollution level released during printer operation. Methods From 9:00 to 16:00 on January 4 to 6, 2021, 20 faculty offices in a university in Beijing were selected by convenient sampling to measure the indoor particulate matter level during printing, and to investigate the printing equipment usage of 31 users in the offices. Besides, experiments were designed to explore the influence of position and distance from a printer, ventilation, and the distance between a printer and a nearby window during ventilation on the number concentration of particulate matter released by the printers. Results Except one printer being placed on the ground, the other 30 printers were placed on office desks (0.71±0.16) m above the ground. Among them, 65% of the printers (n=20) were less than 1 m away from the users horizontally, and 74% of the users (n=23) accessed the printers 1-5 times a week, printing (7.03±4.07) pages per time. The peak mass concentrations in users' offices during printing of PM10, PM2.5, and PM1 were (21.96±12.96), (7.92±5.54), and (5.77±5.00) μg·m−3, respectively, and the peak number concentration of PM0.25−0.28 was (40941±36926) P·L−1. The experiments showed that when the particle sizer was located in the front, side, and back of the printers, the peak values of PM0.25−0.28 number concentration during printing were (24257±551), (12588±1354), and (11192±249) P·L−1, respectively, and the difference among them was statistically significant (F=214.9, P<0.01); when the particle sizer was placed 0.1, 0.2, and 0.3 m away from the printers, the peak values of PM0.25−0.28 number concentration during printing were (24257±551), (19847±1426), and (16480±878) P·L−1, respectively, and the difference among them was statistically significant (F=44.66, P<0.01); when the experiment room was ventilated or not, the peak values of PM0.25−0.28 number concentration during printing were (18595±488) and (24257±551) P·L−1, respectively, and the difference between them was statistically significant (F=192.6, P<0.01); when the distance between the printer and the window was 1, 2, 3 m, the peak values of PM0.25-0.28 number concentration during printing were (16780±823), (18347±348), and (18595±488) P·L−1, respectively, and the difference among them was statistically significant (F=8.407, P<0.05). Conclusion The overall printer workload is small and the concentration of particulate matter in the faculty offices is low when the printers are working. Printer position, distance, ventilation, and the distance from a nearby window under ventilation conditions are factors affecting the concentration of particulate matter released by the printers.

Nosocomial infection control strategy in cabin hospitals during the epidemic of COVID-19 / 中华医院管理杂志

Large cabin hospitals prove a vital role in " admitting all" of the COVID-19 patients with mild symptoms in the overall measures against the epidemic.For such hospitals, nosocomial infection management to prevent epidemic spreading is a prerequisite and guarantee. The authors studied the operation processes of Dongxihu cabin hospital in Wuhan, and probed into such aspects as personal protection, environmental sanitation management, item management, occupational exposure disposal, and discharged patient management. The paper also analyzed common and critical problems in operation, for references to other cabin hospitals or makeshift treatment facilities.

Influencing factors of work-related musculoskeletal disorders among dentists / 中国职业医学

OBJECTIVE: To analyze the prevalence of work-related musculoskeletal disorders(WMSDs) among dentists and explore its influencing factors. METHODS: A total of 455 dentists from 9 medical organizations of Beijing and Fuzhou cities were selected as study subjects. The disease occurrence and mental workload were investigated using China Musculoskeletal Disorders Questionnaire and Subjective Workload Assessment Technique. The influencing factors of WMSDs were analyzed by multivariate logistic regression. RESULTS: The total prevalence of WMSDs was 58.9%(268/455) among dentists. The top three body parts of WMSDs were neck(41.5%), shoulder(33.6%) and lower back(28.1%). The median of mental workload score was 58. Multivariate logistic regression analysis results indicated that female dentists showed a higher risk than male dentists(P<0.01) after excluding the influence of confounding factors. The higher the length of service, the higher their risk for WMSDs(P<0.01). Dentists who hold their heads sideways for long time, bent frequently, and use vibrating tools had relatively high risks of developing WMSDs(P<0.01). Dentists who use armchairs had a relatively low risk of WMSDs(P<0.01). There was no correlation between the mental workload and the prevalence of WMSDs in dentists(P>0.05). CONCLUSION: The prevalence of WMSDs among dentists is high. Individual factors, awkward posture and using vibrating tools are risk factors of WMSDs among dentists.Armchair use can help reduce the risk of WMSDs.

Association of lower extremity work-related musculoskeletal disorders and types of working among manufacturing workers / 中国职业医学

OBJECTIVE: To investigate the prevalence of lower extremity work-related musculoskeletal disorders(WMSDs) among manufacturing workers, and to explore the association of lower extremity WMSDs and different types of working. METHODS: A total of 7 908 workers were selected as study subjects from four manufacturing factories in China using the cluster sampling method. The Musculoskeletal Disorders Investigating Questionnaire was adopted to investigate the prevalence of lower extremity WMSDs and the distribution of types of working. The prevalence ratio(PR) of WMSDs, calculated by log-binomial model, was used to estimate the correlation of WMSDs in different parts of lower extremity. The multi-factor logistic regression was used to analyze the association of lower extremity WMSDs and different types of working. RESULTS: The total annual prevalence of lower extremity WMSDs was 41.0%(3 241/7 908) among manufacturing workers. The annual prevalence of WMSDs of different parts in lower extremity from high to low were knee(29.5%), ankle/foot(23.9%) and hip/thigh(16.7%). The correlation of WMSDs of the three parts in lower extremity was close, and the range of PR values was 2.21-3.88. The result of logistic regression analysis showed that the workers who frequently sat for long periods had higher risk of lower extremity WMSDs than those who never/rarely sat for long periods(odds ratio=1.39, P<0.01). The higher the frequency of standing, kneeling/squatting for long periods, carrying heavy loads ≥5 kg and driving, the higher the risk of lower extremity WMSDs(the odds ratios were 1.33, 1.41, 1.16 and 1.12, respectively, P<0.01). CONCLUSION: The prevalence of lower extremity WMSDs was relatively high among manufacturing workers. There is a dose-effect relationship between the types of working and lower extremity WMSDs.

Establishment and verification of the Chinese Musculoskeletal Questionnaire——The questionnaire is attached in the attachment / 中国职业医学

OBJECTIVE: To compile the Chinese Musculoskeletal Questionnaire(CMQ) and test its reliability and validity. METHODS: The initial CMQ was formed through studying literatures, interviewing professional workers who have work-related musculoskeletal disorders(WMSDs) and investigation with occupational health and ergonomics experts. Then, 436 and 443 manufacturing workers were selected as prediction and verification samples respectively by convensence sampling method. The reliability and validity of the CMQ were tested by item analysis, exploratory factor analysis and confirmatory factor analysis. RESULTS: i) The CMQ composed of 48 items with item analysis. ii) Nine common factors of CMQ were extracted using exploratory factor analysis, which explained 70.721% of WMSDs variance. iii) The results of confirmatory factor analysis showed that the ratio of chi-square to degree of freedom was 3.380, the comparative fit index was 0.781, the Tucker-Lewis index was 0.764, the root mean square error of approximation was 0.073, and the standardized root mean square residual was 0.068. iv) The results showed that the item reliabilities of the 9 common factors of CMQ such as upper and lower limbs posture load, neck posture load, back posture load, job demand, social support, job control, job environment, job system and job facilities were 0.205-0.841, the composite reliabilities were 0.545-0.894, and the convergence efficiencies were 0.377-0.834. The correlation coefficients between the common factors were less than its square root of the convergence validities. CONCLUSION: The CMQ has good reliability and validity, and is a reliable and effective tool for evaluating WMSDs.

Nosocomial infection control strategy in cabin hospital during the outbreak of COVID-19 / 中华医院管理杂志

The construction of mobile Cabin hospitals is a pioneering effort for the prevention and controlling of the patients with mild symptoms during the outbreak epidemic of Novel Coronavirus Pneumonia. It is a prerequisite and important guarantee for the hospital to manage the hospital infection and prevent the spreading of the epidemic. Our team is located in Dongxihu mobile Cabin hospital, which is one of the first three Cabin hospitals in Wuhan. This article takes the operation process of this hospital as a clue, and discusses aspects of personal protection, environmental sanitation management, item management, occupational exposure disposal, and discharged patient management. It also analyzed common and critical problems in operation. With a view to provide reference for other Cabin hospitals or temporary treatment agencies.

Application of CiteSpace software in the visualization analysis of work-related musculoskeletal disorders / 中华劳动卫生职业病杂志

Objective@#To investigate the visual application of the CiteSpace software in the field of work-related musculoskeletal disorders (WMSDs) .@*Methods@#The literature on WMSDs research, published from 1991 to 2017, was retrieved in Web of Science database. The CiteSpace 5.2 was used to make visualization analysis on the hotspots and tendency of the keywords, authors, countries (regions) and research institutes in relevant literature.@*Results@#A total of 3224 literatures were included in the analysis. The amount of the literatures published was increasing annually. The key word co-occurrence network showed that the research hotspots mainly focused on the study of epidemiology, risk factors, symptoms, and other aspects of WMSDs. The cooperation network and time network of counties and regions showed that America and Europe were at the leading position in the field of WMSD, and the top three were America, Canada and Sweden. The developing countries, like Brazil and China, had also begun to make relative research since 2000. In research cooperation, the collaboration among countries, research institutions was relatively close, and multiple leading core authors and teams were formed in the international arena.@*Conclusion@#The CiteSpace software can directly demonstrate the hotspots and tendency in the area of WMSDs.

Analysis of characteristics and influencing factors of fine particulate matters and submicron particulate matters in printing shop / 中华预防医学杂志

Objective@#To analyze the physical characteristics of fine particulate matters (PM2.5) and submicron particulate matters (PM1), and investigate the factors influencing the emission peak of printer particles.@*Methods@#A 12-hour particle concentration monitoring for PM2.5 and PM1 was conducted in a printing shop on January 5th, 2018. PM2.5 in the air was analyzed after the monitoring process to figure out morphological characteristics and element composition of printer particles. Besides, experiments were carried out in an enclosed space to detect the number concentration peaks of PM1 during every printing process. Influencing factors investigated in this study were printer types, toner coverages and interval time between different printing processes.@*Results@#The 12-hour particles concentration monitoring showed that the number concentration of PM1 and the mass concentration of PM2.5 were 7.510×104 pt/cm3 and 96.85 μg/m3. The diameter of most PM2.5 was less than 100 nm, with a fractal dimension of 2.591. Most PM2.5 appeared as regular spheres with typical agglomeration phenomenon, while some were in rhabditiform or irregular shapes. Element analysis showed that PM2.5 was mainly composed of C, O, Si, Ca, with less metallic element. The PM1 emission peak values of three printers were 3.60×104, 3.43×104, 0.31×104 pt/cm3, respectively and the difference was not statistically significant (χ2=5.42, P>0.05). When the page coverage rate was 0%, 2.5%, 5%, 10%, 20% and 50%, the PM1 emission peak value of printer A was 6.74×104, 4.62×104, 3.82×104, 2.82×104, 1.00×104 and 1.08×104 pt/cm3, and the difference was also not statistically significant (χ2=7.01, P>0.05). The natural logarithm of PM1 emission peak value in printing work was associated with the resting time before printing and the change value of heating roller temperature (r value was 0.83 and 0.89, respectively, all P values<0.05).@*Conclusion@#PM2.5 and PM1 in the printing shop stayed at a high level. Particles appeared as various shapes and element compositions were complex. The temperature change of heating roller was one of most important factors that lead to the increased number concentration peak of PM1.

Analysis of antibiotic resistance and influencing factors for Helicobacter pylori in children / 中华实用儿科临床杂志

Objective@#To investigate the antibiotic resistance of Helicobacter pylori(Hp) isolates cultured from endoscopic gastric mucosal samples and influencing factors for antibiotic resistance in children.@*Methods@#From April 2013 to February 2016, Hp cultured from mucosa samples of the gastric antrum and the body of stomach was investigated in 246 patients with 13C breath test positive examined by gastroscopy.Resistance to Amoxicillin, Clarithromycin, Metronidazole, Tetracycline was tested for Hp by using E-test.The clinical data were collected from the patients, and the relationship among age, gender, endoscopic diagnosis, histological performance, eradication number factors and antibiotic resistance rate were analyzed.@*Results@#Of 246 specimens, 174 cases (70.7%) were positive.The overall antibiotic resistance rates of isolates obtained were 96.55% (168/174 cases), 57.47% (100/174 cases), 4.02% (7/174 cases), 1.15%(2/174 cases) with respect to Clarithromycin, Metronidazole, Tetracycline and Amoxicillin.An antibiotic resistance rate was 43.10% (75/174 strains), among which the Clarithromycin resistance rate was 93.33% (70/75 strains), and the Metronidazole resistance rate was 6.67% (5/75 strains). Double resistance rate was of 54.02%(94/174 strains), among which the resistances rate of Clarithromycin+ Metronidazole was 52.30%(91/94 strains), and the resistances rate of Clarithromycin+ Tetracycline was 1.72%(3/94 strains). Triple resistance rate of Clarithromycin+ Metronidazole+ Tetracycline was 1.15%(2/174 strains). Quadruple resistance rate of Clarithromycin+ Metronidazole+ Amoxicillin+ Tetracycline was 1.15%(2/174 strains). Factor analysis showed that the resistance rate of Clarithromycin in children who had failed in eradication therapy [98.7%(148/150 cases)] was higher than that in children who had not undergone eradication therapy [83.3%(20/24 cases)], and the difference was statistically significant(χ2=14.610, P<0.05). There was no significant difference in the relationship between Hp resistance to Metronidazole and Clarithromycin and the age, gender, endoscopic diagnosis and histological manifestations(all P>0.05).@*Conclusions@#Hp resistance rate to Clarithromycin, Metronidazole is very high in children, but it is relatively low to Amoxicillin and Tetracycline, and multiple antibiotic resistance is at high prevalence.

Analyzing the potential category of occurrence pattern of musculoskeletal disorders among workers in an electronic parts processing factory / 中国职业医学

OBJECTIVE: To explore the occurrence pattern of work-related musculoskeletal disorders( WMSDs) in electronic parts processing workers. METHODS: A total of 498 workers from an electronic parts processing factory were selected as study subjects by judgement sampling method. The prevalence of WMSDs in the past 1 year was investigated by using the China Musculoskeletal Questionnaire. The potential category model was used to classify the categories of WMSDs. RESULTS: The incidence of WMSDs in the past 1 year was 46. 8%( 233/498). Among them,the incidence of WMSDs involving only one site was 13. 1%( 65/498),and those involving at least 2 sites were 33. 7%( 168/498). The multi-site WMSDs were about 6-58 times of the single-site WMSDs. According to potential category analysis,the occurrence patterns of WMSDs were divided into three categories: i) cervical and shoulder occurrence group( 135 persons,27. 1%); ii) all parts group( 31 persons,6. 2%); iii) few or no site group( 332 persons,66. 7%). CONCLUSION: The occurrence of multi-site WMSDs in electronic parts processing workers were more common than the single-site. Analysis of potential category can be used to explore the occurrence pattern of WMSDs.

Analyzing the influencing factors of multisite work-related musculoskeletal disorders among workers in a railway vehicle manufacturing enterprise / 中国职业医学

OBJECTIVE: To analyze the prevalence and influencing factors of multisite work-related musculoskeletal disorders(WMSDs) of workers in a railway vehicle manufacturing enterprise. METHODS: A total of 366 male workers in the assembly and riveting workshop of a railway vehicle manufacturing enterprise were selected as the research subjects using the cluster sampling method. The Chinese Musculoskeletal Questionnaire was used to investigate the prevalence of multiple sites of WMSDs. Multiple logistic regression analysis was used to analyze the influencing factors. RESULTS: The total prevalence of WMSDs was 56.3%(206/366). The prevalence of WMSDs in all parts from high to low was as follows: lower back(35.5%), hand and wrist(27.6%), neck(23.2%), shoulder(21.0%), knee(19.9%), upper back(18.6%), hip and leg(18.0%), ankle/foot(15.8%) and elbow(12.3%)(P<0.01). The total prevalence of multisite WMSDs was 38.0%(139/366). The prevalence of WMSDs in different numbers of parts from high to low was as follows: 6 or more parts(12.0%), 2 parts(10.7%), 3 parts(6.6%), 5 parts(5.5%) and 4 parts(3.3%)(P<0.01). Multiple logistic regression analysis results showed that the overweight and obese workers had higher risk of multi site WMSDs than those with normal body mass index(P<0.05).Those with long-term low heads, frequent bending, long bending of the elbows, and higher frequency of work requirements, and less frequently communicated with the leader had higher risk of multi site WMSDs(P<0.05). CONCLUSION: The prevalence of multisite WMSDs in railway vehicle manufacturing enterprise is relatively high. The influencing factors include individual factors, adverse ergonomic factors and psychosocial factors.