Three-Dimensionally Printed, Vertical Full-Color Display Pixels for Multiplexed Anticounterfeiting

Information encryption strategies have become increasingly essential. Most of the fluorescent security patterns have been made with a lateral configuration of red, green, and blue subpixels, limiting the pixel density and security level. Here we report vertically stacked, luminescent heterojunction micropixels that construct high-resolution, multiplexed anticounterfeiting labels. This is enabled by meniscus-guided three-dimensional (3D) microprinting of red, green, and blue (RGB) dye-doped materials. High-precision vertical stacking of subpixel segments achieves full-color pixels without sacrificing lateral resolution, achieving a small pixel size of ∼μm and a high density of over 13,000 pixels per inch. Furthermore, a full-scale color synthesis for individual pixels is developed by modulating the lengths of the RGB subpixels. Taking advantage of these unique 3D structural designs, trichannel multiplexed anticounterfeiting Quick Response codes are successfully demonstrated. We expect that this work will advance data encryption technology while also providing a versatile manufacturing platform for diverse 3D display devices.

[Baseline survey of psychosocial factors levels and their health effects in a cohort study of natural gas field workers]

Objective: To investigate the level of psychosocial factors in workplace and their health effects among workers in a natural gas field. Methods: A prospective and open cohort of natural gas field workers was established to study the level of workplace psychosocial factors and their health effects, with a follow-up every 5 years. In October 2018, a cluster sampling method was used to conduct a baseline survey of 1737 workers in a natural gas field, including a questionnaire survey on demographic characteristics, workplace psychosocial factors and mental health outcomes, physiological indicators such as height and weight, and biochemical indicators such as blood routine, urine routine, liver function and kidney function. The baseline data of the workers were statistically described and analyzed. The psychosocial factors and mental health outcomes were divided into high and low groups according to the mean score, and the physiological and biochemical indicators were divided into normal and abnormal groups according to the reference range of normal values. Results: The age of 1737 natural gas field workers was (41.8±8.0) years old, and the length of service was (21.0±9.7) years. There were 1470 male workers (84.6%). There were 773 (44.5%) high school (technical secondary school) and 827 (47.6%) college (junior college) graduates, 1490 (85.8%) married (including remarriage after divorce), 641 (36.9%) smokers and 835 (48.1%) drinkers. Among the psychosocial factors, the detection rates of high levels of resilience, self-efficacy, colleague support and positive emotion were all higher than 50%. Among the mental health outcomes evaluation indexes, the detection rates of high levels of sleep disorder, job satisfaction and daily stress were 41.82% (716/1712), 57.25% (960/1677) and 45.87% (794/1731), respectively. The detection rate of depressive symptoms was 22.77% (383/1682). The abnormal rates of body mass index (BMI), triglyceride and low density lipoprotein were 46.74% (810/1733), 36.50% (634/1737) and 27.98% (486/1737), respectively. The abnormal rates of systolic blood pressure, diastolic blood pressure, uric acid, total cholesterol and blood glucose were 21.64% (375/1733), 21.41% (371/1733), 20.67% (359/1737), 20.55% (357/1737) and 19.17% (333/1737), respectively. The prevalence rates of hypertension and diabetes were 11.23% (195/1737) and 3.45% (60/1737), respectively. Conclusion: The detection rates of high level psychosocial factors in natural gas field workers are high, and their effects on physical and mental health remain to be verified. The establishment of a cohort study of the levels and health effects of psychosocial factors provides an important resource for confirming the causal relationship between workplace psychosocial factors and health.

Nonlinear Optical Activities in Two-Dimensional Gallium Sulfide: A Comprehensive Study

The nonlinear optical (NLO) properties of two-dimensional (2D) materials are fascinating for fundamental physics and optoelectronic device development. However, relatively few investigations have been conducted to establish the combined NLO activities of a 2D material. Herein, a study of numerous NLO properties of 2D gallium sulfide (GaS), including second-harmonic generation (SHG), two-photon excited fluorescence (TPEF), and NLO absorption are presented. The layer-dependent SHG response of 2D GaS identifies the noncentrosymmetric nature of the odd layers, and the second-order susceptibility (χ²) value of 47.98 pm/V (three-layers of GaS) indicates the superior efficiency of the SHG signal. In addition, structural deformation induces the symmetry breaking and facilitates the SHG in the bulk samples, whereas a possible efficient symmetry breaking in the liquid-phase exfoliated samples results in an enhancement of the SHG signal, providing prospective fields of investigation for researchers. The generation of TPEF from 800 to 860 nm depicts the two-photon absorption characteristics of 2D GaS material. Moreover, the saturable absorption characteristics of 2D GaS are realized from the largest nonlinear absorption coefficient (β) of -9.3 × 10³, -91.0 × 10³, and -6.05 × 10³ cm/GW and giant modulation depths (T_s) of 24.4%, 35.3%, and 29.1% at three different wavelengths of 800, 1066, and 1560 nm, respectively. Hence, such NLO activities indicate that 2D GaS material can facilitate in the technical advancements of future nonlinear optoelectronic devices.

Two-Photon Lasing from Two-Dimensional Homologous Ruddlesden-Popper Perovskite with Giant Nonlinear Absorption and Natural Microcavities

Two-dimensional Ruddlesden-Popper perovskites (RPPs) with multiple quantum well-like structures, strong excitonic quantum confinement, and high stability are promising optical gain media. However, the lasing from such material with a small number of inorganic well layers is difficult to achieve. Herein, we demonstrate the low-threshold upconversion lasing from the homologous RPP (PEA)₂(MA)_n-1Pb_nI_3n+1 (n = 2 and 3) microflakes with wavelength varies from 598 to 637 nm under 800 nm laser excitation at low temperature (≤153 K). Using the micro Z-scan technique, we discovered that the RPP flakes have a giant two-photon absorption coefficient β as high as 3.6 × 10³ cm GW^-1, resulting in the effective upconversion transition under two-photon excitation. Furthermore, the self-formation of Fabry-Pérot microcavities provides the support for lasing emission from the n ≥ 2 RPP flakes. Calculation results and microscopic transient absorption measurements reveal that low-threshold lasing is due to the high differential gain coefficient and the suppressed nonradiative Auger recombination rate inside the quantum confinement structures. These properties enable RPPs as potential gain media for developing upconversion microcavity lasers.

[A descriptive analysis of tea consumption in adult twins in China]

Objective: To describe the distribution characteristics of tea consumption in adult twins recruited in the Chinese National Twin Registry (CNTR) and provide clues to genetic and environmental influences on tea consumption. Methods: Enrolled in CNTR during 2010-2018, 25 264 twin pairs aged 18 years and above were included in subsequent analysis. Random effect models were used to estimate tea consumption in the population and regional distribution characteristics. The concordance rate of the behavior and difference in consumption volume of tea within pairs were also described. Results: The mean age of all subjects was (35.38±12.45) years old. The weekly tea consumers accounted for 17.0%, with an average tea consumption of (3.36±2.44) cups per day. The proportion of weekly tea consumers was higher among males, 50-59 years old, southern, urban, educated, and the first-born in the twin pair (P<0.05), and lower among unmarried individuals (P<0.001). Within-pair analysis showed that the concordance rate of tea consumption of monozygotic (MZ) twins was higher than that of dizygotic (DZ) twins and the overall heritability of tea consumption was 13.45% (11.38%-15.51%). Stratified by the characteristics mentioned above, only in males, the concordance rate of MZ showed a tendency to be greater than that of DZ (all P<0.05). The differences in consumption volume of tea within twin pairs were minor in MZ among males (P<0.05), while the differences were not significant in female twins. Conclusion: There were discrepancies in the distribution of tea consumption among twins of different demographic and regional characteristics. Tea consumption was mainly influenced by environmental factors and slightly influenced by genetic factors. The size of genetic factors varied with gender, age, and region, and gender was a potential modified factor.

[A case-control study on the relationship between DNA methylation and occupational noise hearing loss]

Objective: To explore the relationship between DNA methylation and occupational noise-induced hearing loss. Methods: A case-control study was conducted. People with hearing loss induced by occupational noise were recruited as the case group and those with normal hearing but still exposed to occupational noise were recruited as the control group. A total of 60 participants were included, of which 30 participants were in the case group and 30 in the control group. The methylation level was detected by 850k genome-wide DNA methylation chip technology. The significance of differential methylated position (DMP) was tested by R-packet 'Champ'. The differential methylated region (DMR) was analyzed by using Champ's Bumphunter algorithm. Cluster profiler was used to analyze the gene list for GO and KEGG pathway enrichment. Results: There was significant difference between two groups in binaural high-frequency average hearing threshold (P<0.05), but there was no significant difference in age, smoking, drinking, hypertension, physical exercise and cumulative noise exposure. The results of DMP and DMR analysis showed that 713875 sites were detected in the case group and the control group, and 439 methylation sites with significant difference, accounting for 0.06%; 650 regions were detected, and 72 methylation regions with significant differences, accounting for 11.08%. Compared with the control group, the results of GO enrichment analysis showed that the case group had statistically significant differences in four pathways: axogenesis of projection neurons in the central nervous system, neuronal development in the central nervous system, axogenesis of neurons in the central nervous system and neuronal differentiation in the central nervous system. KEGG enrichment analysis showed that there were significant differences in sphingolipid metabolism, aldosterone synthesis and secretion, primary bile acid biosynthesis pathway between the case group and the control group. Conclusion: The occurrence of occupational noise-induced hearing loss may be related to the regulation of gene expression related to axogenesis of projection neurons in the central nervous system, development of neurons in the central nervous system, axogenesis of neurons in the central nervous system, differentiation of neurons in the central nervous system, sphingolipid metabolism, aldosterone synthesis and secretion, primary bile acid biosynthesis and gene methylation related to metabolism.

[A descriptive analysis on coronary heart disease in adult twins in China]

Objective: To describe the distribution characteristics of coronary heart disease in adult twins recruited from Chinese Twin Registry (CNTR), and provide clues and evidence for the effect of genetic and environmental influences on coronary heart disease. Methods: By using the data of CNTR during 2010-2018, a total of 34 583 twin pairs aged ≥18 years who completed questionnaire survey and had related information were included in the current study to analyze the population and area distribution characteristics of coronary heart disease. Random effect models were used to compare the differences between groups. The concordane rate of coronary heart disease were calculated respectively in monozygotic (MZ) twin pairs and dizygotic (DZ) twin pairs to estimate the heritability. Results: The twin pairs included in this analysis were aged (34.2±12.4) years. The overall prevalence rate of coronary heart disease in twin pairs was 0.7%. Twin pairs who were women, older, obese and lived in northern China had higher prevalence of coronary heart disease (P<0.05). Intra-pair analysis in the same-sex twin pairs found that the concordane rate of coronary heart disease was higher in MZ twin pairs (25.3%) than in DZ twins (7.4%), and the difference was statistically significant (P<0.001). The overall heritability of coronary heart disease was 19.3% (95%CI: 11.8%-26.8%). Stratified by gender, age and area, the concordane rate was still higher in MZ twin pairs than in DZ pairs. Participants who were women, aged 18-30 years or ≥60 years and lived in northern China had a higher heritability of coronary heart disease. Conclusion: The distribution of coronary heart disease in twin pairs differed in populations and areas. The prevalence of coronary heart disease was affected by genetic factors, but the effect varied with age, gender and area.

[A descriptive analysis on type 2 diabetes in twins in China]

Objective: To describe the distribution characteristics of type 2 diabetes in twins in Chinese National Twin Registry (CNTR), provide clues and evidence for revealing the influence of genetic and environmental factors for type 2 diabetes. Methods: Of all twins registered in the CNTR during 2010-2018, a total 18 855 twin pairs aged ≥30 years with complete registration information were included in the analysis. The random effect model was used to describe the population and area distribution characteristics and concordance of type 2 diabetes in twin pairs. Results: The mean age of the subjects was (42.8±10.2) years, the study subjects included 10 339 monozygotic (MZ) twin pairs and 8 516 dizygotic (DZ) twin pairs. The self-reported prevalence rate of type 2 diabetes was 2.2% in total population and there was no sighificant difference between MZ and DZ. Intra-twin pairs analysis showed that the concordance rate of type 2 diabetes was 38.2% in MZ twin pairs, and 16.0% in DZ twin pairs, the difference was statistically significant (P<0.001). The concordance rate of type 2 diabetes in MZ twin parts was higher than that in DZ twin pairs in both men and women, in different age groups and in different areas (P<0.05). Further stratified analysis showed that in northern China, only MZ twin pairs less than 60 years old were found to have a higher concordance rate of type 2 diabetes compared with DZ twin pairs (P<0.05). In southern China, the co-prevalence rate in male MZ twin pairs aged ≥60 years was still higher than that in DZ twin pairs (P<0.05). Conclusion: The twin pairs in this study had a lower self-reported prevalence of type 2 diabetes than the general population. The study results suggested that genetic factors play a role in type 2 diabetes prevalence in both men and women, in different age groups and in different areas, however, the effect might vary.

Unlocking surface octahedral tilt in two-dimensional Ruddlesden-Popper perovskites

Molecularly soft organic-inorganic hybrid perovskites are susceptible to dynamic instabilities of the lattice called octahedral tilt, which directly impacts their carrier transport and exciton-phonon coupling. Although the structural phase transitions associated with octahedral tilt has been extensively studied in 3D hybrid halide perovskites, its impact in hybrid 2D perovskites is not well understood. Here, we used scanning tunneling microscopy (STM) to directly visualize surface octahedral tilt in freshly exfoliated 2D Ruddlesden-Popper perovskites (RPPs) across the homologous series, whereby the steric hindrance imposed by long organic cations is unlocked by exfoliation. The experimentally determined octahedral tilts from n = 1 to n = 4 RPPs from STM images are found to agree very well with out-of-plane surface octahedral tilts predicted by density functional theory calculations. The surface-enhanced octahedral tilt is correlated to excitonic redshift observed in photoluminescence (PL), and it enhances inversion asymmetry normal to the direction of quantum well and promotes Rashba spin splitting for n > 1.

Robust and Flexible Random Lasers Using Perovskite Quantum Dots Coated Nickel Foam for Speckle-Free Laser Imaging

The advantage of using flexible metallic structures as the substrate of flexible lasers over plastic materials is its strong mechanical strength and high thermal conductivity. Here, it is proposed to deposit CsPbBr₃ perovskite quantum dots onto Ni porous foam for the realization of flexible lasers. Under two-photon 800 nm excitation at room temperature, incoherent random lasing emission is observed at ≈537 nm. By external deformation of the Ni porous foam, incoherent random lasing can be tuned to amplified spontaneous emission as well as the corresponding lasing threshold be controlled. More importantly, it is demonstrated that the laser is robust to intensive bending (>1000 bending cycles) with minimum effect on the lasing intensity. This flexible laser is also shown to be an ideal light source to produce a "speckle" free micro-image.

[Application and prospect of multiomics techniques in susceptibility to occupational noise hearing loss]

With the continuous innovation of technology, genomics and other omics techniques, such as transcriptomics, proteomics, and metabolomics, are increasingly becoming an important basis for precision medicine. Current research on susceptibility to occupational noise hearing loss (ONHL) has focused on genomics. Building the future of precision medicine is the focus of current ONHL research. Compared to single-omics studies, the use of multi-omics analysis can provide an integrated flow of information on ONHL susceptibility. This paper outlines the advantages and limitations of different histological techniques and the application of each histology in the disease, and focuses on the feasibility of applying multi-omics techniques in ONHL susceptibility research. The analysis of multi-omics techniques can better guide the comprehensive understanding of the disease in clinical research.

[Effect of occupational stress on depression in gas field workers]

Objective: To explore the occurrence level of depressive symptoms and it's influencing factors among gas field workers. Methods: In October 2018, a cross-sectional study was conducted in 1726 gas field workers from a gas field by using cluster sampling method. Questionaire was used to evaluate the individual factors, depressive symptoms, occupational stress factors and stress regulatory factors. The correlation between depressive symptoms and occupational stress was analyzed. Multivariate logistic regression was used to analyze the influencing factors of depressive symptoms. Results: The depressive symptoms score of gas field workers was 12.00 (7.00, 19.00) point. Correlation analysis revealed that depressive symptoms score was positively related to sleep disorders (r=0.598) , effort (r=0.186) , daily tension (r=0.478) , negative affectivity (r=0.565) , social support (r=0.446) and monotony of work (r=0.484) (P<0.01) . And it was negatively related to reward (r=-0.386) , work stability (r=-0.294) , promotion opportunities (r=-0.258) , positive affectivity (r= -0.310) , self-efficacy (r=-0.312) , contral strategy (r=-0.268) , support strategy (r=-0.209) and job satisfaction (r=-0.398) (P<0.01) . Multivariate logistic regression analysis revealed that sleep disorder, high negative affectivity, low support from colleagues, low support from family, high monotony of work and high daily tension were the risk factors for depressive symptoms of gas field worker (OR=3.423, 95%CI: 2.644-4.397; OR=2.847, 95%CI: 2.200-3.683; OR=1.646, 95%CI: 1.215-2.116; OR=1.496, 95%CI: 1.164-1.923; OR=1.578, 95%CI: 1.227-2.303; OR=1.903, 95%CI: 1.480-2.440; P<0.01) . High work stability, high self-efficacy and high job satisfaction were protective factors for depressive symptoms of gas field workers (OR=0.752, 95%CI: 0.591-0.958; OR=0.590, 95%CI: 0.465-0.749; OR=0.718, 95%CI: 0.516-0.999; P<0.05) . Conclusion: Occupational stress factors have a great influence on the depressive symptoms of gas field workers. Increased work stability, self-efficacy and job satisfaction could reduce the risk of depressive symptoms.

[Correlation between social support and occupational stress among gas production workers in the field]

Objective: To investigate the level of social support and its correlation with occupational stress among gas production workers in the field. Methods: In October 2018, the cluster sampling method was used to perform a cross-sectional survey for 1726 gas production workers in the field, and related data of these workers were collected, including age, education level, marital status, level of social support, and related factors for occupational stress. A Spearman's rank correlation analysis was used to investigate the correlation between social support and occupational stress, and the levels of occupational stress-related factors were compared between the groups with different social support scores. Results: The gas production workers in the field had a median (25th percentile, 75th percentile) social support score of 24.00 (19.00, 28.00) , and there was a significant difference in social support score between the workers with different posts or work shifts (P<0.01) . Social support score was positively correlated with effort, daily stress, negative emotion, and job routinization (P<0.05) and was negatively correlated with job satisfaction, reward, working stability, and promotion opportunity (P<0.05) . The group with a high social support score had significantly higher scores of effort, job routinization, sleep disorders, and daily stress than the other two groups (P<0.01) , and the group with a low social support score had significantly higher scores of reward, self-efficacy, positive affection, and job satisfaction than the other two groups (P<0.01) . Conclusion: High-level social support plays an important role in alleviating occupational stress and protecting mental health among gas production workers in the field.

[Interaction of shift work and psychological capital on abnormal glucose and lipid metabolism among natural gas field workers]

Objective: To explore the interaction between shift work and psychological capital on abnormal glucose and lipid metabolism. Methods: A convenient sampling survey of demographics characteristics, shift work and psychological capital was conducted on 1 415 natural gas field workers by questionnaire in October 2018,and their physiological and biochemical indexes were measured according to standard norms. Multivariate logistic regression model was used to analyze the interaction between shift work and psychological capital on abnormal glucose and lipid metabolism. Results: For 1 415 subjectsthe prevalence of abnormal blood glucose was 21.2%, the prevalence of diabetes was 8.3%.The prevalence of abnormal total cholesterol was 40.4%, the prevalence of hypercholesterolemia was 11.3%.The prevalence of abnormal triglyceride was 41.6%, the prevalence of hypertriglyceridemia was 24.7%.The detection rate of Low-density Lipoprotein was 17.3%, the detection rate of Low-density Lipoprotein was 4.0%, and the detection rate of high-density Lipoprotein was 1.3%. Multiple logistic regression model analysis showed that shift work, the low level of self-efficacy and the low level of optimism was positively associated with abnormal blood glucose, respectively (P<0.05). Shift work was positively associated with abnormal triglyceride (P<0.05). However, there was no interaction between shift work, low self-efficacy, low hope, low resilience, and low optimism on abnormal glucose and lipid metabolism. Conclusion: Shift work was a risk factor of abnormal blood glucose and triglyceride, self-efficacy and optimism were protective factors of abnormal blood glucose. There was no multiplicative interaction between shift work and psychological capital on abnormal glucose and lipid metabolism in the study population.

[A preliminary study on establishment of the Core Occupational Stress Scale (COSS) norms for manufacturing and medical workers in China]

Objective: To establish the Core Occupational Stress Scale (COSS) norm values for manufacturing and medical workers. Methods: A total of 10 316 manufacturing workers of 20 companies from 7 provincial capital cities and 5 031 medical workers of 19 hospitals from 4 provincial capital cities were investigated using a stratified sampling method. Questionnaire information including occupational stress was collected. Norms of mean, percentile and T scores were calculated for COSS total and sub-dimension scores by different demographic characteristics. Based on the normal distribution, cut points of x¯+0.5s, x¯+s, x¯+1.5s of COSS total scores were calculated to classify the degree of occupational stress. Results: The COSS total scores were (45.48±8.16) and (45.71±8.46). The 50th percentiles were both 46, and T score ranges were (15-92) and (16-91), respectively, for manufacturing and medical workers. When the total score was<50, 50-53, 54-57, and >57 for manufacturing worker, or<50, 50-54, 55-58, and >58 for medical workers, occupational stress would be classified into none, mild, moderate, and severe levels. Conclusion: Compatible with the national condition of China, as well as the principles of psychological measurement, these norm values for manufacturing and medical workers could provide theoretical support and practical guideline on occupational mental health promotion.

[Development of the Core Occupational Stress Scale for occupational populations in China]

Objective: To develop the Core Occupational Stress Scale (COSS) for key occupational populations, and to assess the reliability and validity of COSS in China. Methods: According to the literature review, in-depth interview and expert evaluation, the item pool of COSS was established. A total of 20 981 employees (3 703 employees from 2018 and 17 178 employees from 2019) of manufacturing, medical, and traffic polices, etc. from Beijing, Tianjin, Shanghai, Chongqing, Jiangsu, Shandong, Zhejiang, Hunan, Guangdong and Hubei were investigated using convenient sampling of those participating in general or occupational health examination of the day. Item differential test and exploratory factor analysis (EFA) were used to screen items from the item pool; confirmatory factor analysis (CFA) was used to test structure validity; criterion and convergent validity were tested by Pearson correlation. Cronbach's α coefficient was used to test the reliability of the scale. Results: The EFA suggested a four-factor structure for a 17-item version of COSS, which were social support, organization and reward, demand and effort, and control. It explained 62.06% of the total variance and factor loadings ranged from 0.447 to 0.918. The CFA confirmed the hypothesized four-factor model (GFI=0.904, CFI=0.912, RMSEA=0.079). The COSS scores were positively correlated with burnout, depressive symptoms, and effort-reward imbalance scores with r ranging from 0.357 to 0.567 (P<0.05). The total COSS and each dimension of Cronbach's α coefficients were 0.772-0.896. Conclusions: The COSS has good reliability and validity and can be used as an occupation stress assessment for occupational populations in China.

[Correlation of job monotony and social support on daily hassle: a cross-sectional study based on natural gas field workers]

Objective: To explore the correlation of job monotony and social support on daily hassle. Methods: A convenient sampling survey of demographics characteristics, job monotony, social support and daily hassle was conducted on 1 466 natural gas field workers by questionnaire in October; 2018. Multivariate logistic regression model was used to analyze the correlation of job monotony and social support on daily hassle. Results: The age of 1 466 subjects was (44.47±8.0) years and the length of service was (20.46±5.77) years. There were 258(17.6%), 173(11.8%), 799(54.5%), 120(8.2%) and 116(7.9%) subjects from production and marketing department, processing plant, branch, maintenance department and emergency center respectively. There were 374(25.5%) and 1 092(74.5%) subjects with high and low level of job monotony, and 398(27.1%), 648(44.2%) and 420(28.6%) subjects with high, middle and low level of social support. There were 464(31.7%) and 1 002(68.3%) subjects with high and low daily tension respectively. Compared with the low level of job monotony, the high level of job monotony had a higher risk of daily hassle(OR=4.83,P<0.001), and compared with the high level of social support, the middle and low level of social support had a higher risk of daily hassle(OR=1.25, 2.24,P<0.05). Conclusion: Job monotony and social support were associated with daily hassle.

[Using the experience of industrilized countries for reference to promote the prevention and control of occupational stress from research to practice]

Occupational stress is one of the major occupational health problems in industrialized countries. In Europe, the United States, Japan, and other countries, occupational stress has been included in the prevention and control of occupational hazards in the workplace. This problem has also become a major risk factor affecting the physical and mental health of the working population in China. Over the last three decades, China had carried out a lot of research on occupational stress and made significant progress, but there is still a big gap between China and industrialized countries in terms of theoretical research on occupational stress, development of measurement tools, research topics and methods, formulation of regulations and standards, and practice of prevention and control. Articles in this key issue report the research on the core scale of occupational stress measurement for the Chinese working population, the scale scoring norm of manufacturing and medical personnel, the research on the relationship between positive psychology variables, and occupational stress and its role in the relationship between occupational stress and health outcomes.

[Airway parameters and reference value range of high-resolution CT reconstruction in general population]

Objective: To investigate the measurement of small airways by high-resolution CT and image post-processing software. Screen and analyze the reconstructed airway parameters in order to find the best imaging biomarker parameters of small airway changes and calculate the reference value range; meanwhile, explore its influencing factors. Methods: From a water plant and a medical school, 169 cases of the general population aged 20 to 60 were selected as research objects, and questionnaire surveys and CT tests were performed, and CT data were reconstructed with image post-processing software. The reference value range of the general population was evaluated, and a linear mixed effect model was used to adjust the age, gender, height, BMI, and smoking status, and analyze the influencing factors of airway parameters. Results: The ratio of sixth-grade tracheal wall area to total tracheal area in the Left B1+2 to carina was (53.01±13.35) %, Left B9 to carina was (50.44±12.98) %, Right B1 to carina was (52.73±12.22) %, and Right B9 to carina was (52.93±11.85) %. The ratio of nineth-grade tracheal wall area to total tracheal area in the Left B1+2 to carina was (44.08±14.66) %, Left B9 to carina was (42.44±15.89) %, Right B1 to carina was (46.51±14.03) %, and Right B9 to carina is (43.54±15.87) %. BMI affect the area of the tracheal wall, all p value<0.05. Conclusion: High-resolution CT small airway morphology can make a preliminary assessment of the susceptible population of small airway-related diseases based on a range of reference values, and prevent and control it in combination with influencing factors.

Ultraviolet C lasing at 263 nm from Ba2LaF7:Yb3+,Tm3+ upconversion nanocrystal microcavities

It is a daunting challenge to realize ultraviolet C (UVC) lasing (i.e., has a wavelength range from 200 to 275 nm) from upconversion nanocrystals due to their low upconversion efficiency. Here, we fabricate Ba₂LaF₇:Yb³⁺(90mol%), Tm³⁺(5mol%) upconversion nanocrystals from amorphous borosilicate glass to support emission at ∼263nm under 980 nm ns laser excitation. The excitation threshold can be further reduced from ∼130 to ∼26.5mJ/cm² by using a cylindrical microcavity. We also found that the growth of defect-free Ba₂LaF₇ nanocrystals with a high concentration of codoping Yb³⁺ and Tm³⁺ ions inside high optical damage threshold borosilicate glass is the key to achieving room-temperature UVC upconversion lasing under high-intensity excitation.

[Application of an occupational health risk assessment method in dioctyl phthalate producing enterprise]

Objective: To find the risk assessment model of [di (2-ethylhexyl) phthalate, DEHP] fitting well for producing companies. Methods: The Cluster Sampling method was used in selecting a DEHP producing company in the occupational health and workplace environment monitoring study conducted between July and August in 2017. Data was collected by site evaluating and workplace environment monitoring. According to GBZ/T 298-2017《Technical Guidelines for Occupational Health Risk Assessment of Chemical Hazards in the Workplace》, a qualitative assessment method and a semi-quantitative comprehensive index method were chosen as the models and were compared. Results: The occupational health risk of the two methods rated 4 (high risk) and 2 (negligible risk) . Conclusion: The semi-quantitative comprehensive index method is more comprehensive and accurate when used to assess the occupational health risk caused by DEHP.

[Analysis on the effect of sound insulation reconstruction in operation room of steel rolling production line in a steel plant]

Objective: To investigate the effect of sound insulation improvement on the noise exposure of workers in the operation room of hot rolling line for wide and heavy plate. Methods: From September 2019 to September 2017, based on the occupational health Survey, the data of 25 fixed operation rooms and workers in operation rooms of a steel rolling production line were collected retrospectively, the noise exposure levels before and after the improvement of sound insulation were statistically analyzed. Results: The noise exposure value of the workers, the qualified rate of 0 Grade 8 hours equivalent noise (L(EX, 8 h)) ≤85 dB (A) and the qualified rate of the design limit value of the operation room were all higher than those before the modification, the difference was statistically significant (P<0.01) , after the renovation, the Class II and above noise hazards were eliminated, the equivalent continuous a sound level (L(Aeq, 8 h)) >75 dB (A) of the workers in the operation room was 8h, and the noise level in the operation room still did not meet the Ergonomics limit standard. Conclusion: The improvement of sound insulation can effectively improve the working environment of noise workplace operating room and reduce the workers'noise exposure level.

[Prediction of KCNQ4gene polymorphism varies with CNE or noise exposure duration on the Risk of NIHL-Cox model analysis based on cohort study]

Objective: The purpose of this study was to explore the association between gene in the potassium recycling pathway 4 (KCNQ4) polymorphisms and the susceptibility to noise-induced hearing loss (NIHL) , and analysis the effect of cumulative noise exposure (CNE) and noise exposure duration on this association. Methods: A nested case-control study with 1∶1 matched was used based on the cohort of noise exposure in a steel factory. A total of 286 cases were selected as the group of hearing loss and 286 controls were chosen according to the matching standards of same gender, same type of work, age difference ≤ 5 years, noise exposure duration ≤ 2 years. The single nucleotide polymorphisms (SNPs) of rs4660468, rs4660470, rs34287852 in KCNQ4 were genotyped by SNPscan(TM) method. The codominant, dominant and recessive models were established to study KCNQ4 polymorphisms and the susceptibility to NIHL by single-factor conditional logistic regression analysis. The COX regression analysis was used to analyze the risk of developing NIHL in individuals with different genotypes along with the extending of noise exposure duration or CNE. Results: In the case of CNE≤96 dB (A) ·year, the risk of developing NIHL in individuals with TA genotype of rs4660470 was 2.197 times than individuals with TT genotypes (95%CI: 1.032~4.677) , and those with TA+AA and TT genotypes (HR=2.467, 95%CI: 1.025~5.934) With the increase of noise exposure duration, in rs4660470, individuals with TA genotype had a higher risk of suffering NIHL than those with TT genotype (HR=1.461, 95%CI: 1.061~2.011) , individuals with TA and/or AA genotype had a earlier risk of suffering NIHL than those with TT genotype. Conclusion: The mutant allele A of rs4660470 in KCNQ4 may be a risk factor for developing NIHL, CNE≤100 dB (A) ·year or the increase of noise exposure duration may further increase the risk of NIHL.

[Association between PON2 gene polymorphisms and susceptibility to noise-induced hearing loss]

Objective: To investigate the relationship between SNP and noise-induced hearing loss (NIHL) susceptibility in occupational noise exposure population in China. Methods: From 6297 for a certain steel works in contact with noise, contact length of 3 years or more and workplace noise exposure intensity of 80 dB (A) , ears or high frequency (3 000, 4 000, 6 000 Hz) average of hearing acuity 40 dB (HL) , or high frequency loss in both ears, on the basis of single whisper frequency (500, 1, 000, 2 000 Hz) average threshold of 26 dB (HL) or object as case group. A case-control study was designed with 1:1 matching. Subjects with the same gender, the same type of work, age ±5 years old, and working age ±2 years after noise exposure were selected as the control group. Subjects with any whisper frequency (500, 1, 000, 2, 000 Hz) whose hearing threshold in any frequency band was ≤25 dB (A) and whose average high-frequency hearing threshold in pure tone hearing test was <35 dB (A) were selected as the control group. Four sites of PON2 gene were genotyped by medium-and high-throughput SNP genotyping. Univariate logistic regression was used to analyze the relationship between single SNP polymorphism and NIHL. Results: A total of 286 case-control pairs were included. Smoking was statistically significant difference between cases and controls (P<0.001) . Conclusion: No statistical difference has been found between single SNP polymorphism and NIHL. At the level of greater than 92 dB of high noise exposure, rs7785846 (CT+TT) genotype is a risk factor for occupational noise deafness, and its OR is 2.74 (95%CI: 1.09-6.89) compared with wild homozygous type (CC) . Conclusion. The rs7785846 (CT+TT) genotype carriers of PON2 gene are more susceptible to hearing impairment when exposed to high noise intensity.

[Association between GSTP1 gene polymorphisms and susceptibility to noise-induced hearing loss]

Objective: To investigate the association between the single nucleotide polymorphisms (SNPS) at rs1695 and rs6591256 in glutathione S-transferase P1 (GSTP1) gene and susceptibility to noise-induced hearing loss in Chinese Han workers exposed to noise. Methods: Using the 1: 1 nested case-control study and taking 6297 workers exposed to noise in a steel plant in Henan province as the cohort study population in July 2019, we screened those who have been exposed to noise for ≥3 years and whose binaural high frequency (3000, 4000, 6000 Hz) average hearing threshold is ≥40 dB (A) into the case group. The control group was selected according to the matching criteria of the same sex, same type of work, and the age difference was not more than 5 years old, and the working age difference was not more than 2 years. 276 subjects were selected into the case group and the control group respectively. The medium and high throughout single nucleotide polymorphism typing technology (SNPscanTM technology) was used to detect the polymorphism of three nucleotide sites of GSR gene, and conditional logistic regression was used to analyze the relationship between single nucleotide polymorphism (SNP) and NIHL, and the relationship between different polymorphic sites and the risk of NIHL after adjusting covariates. After stratification with different cumulative noise exposure (CNE) , Conditional logistic regression analysis was used to analysis the risk of NIHL at different loci. Results: The mean and standard deviation of age of the selected subjects was (40.28±8.00) , the mean and standard deviation of noise-exposed working years was (18.7±8.92) years. The range of noise exposure levels and comulative noise exposure were 80.05-93.35dB (A) and 86.83-107.92 dB (A) ·year, respectively. Compared with the control group, there were no statistically significant differences in age, noise-exposured working years, intensity of noise exposure, CNE, gender, drinking, hypertension prevalence and noise exposure level in the hearing loss group (P>0.05) , while there were statistically difference in smoking, binaural high-frequency average hearing threshold and binaural speech frequency (P<0.05) . After adjusting for smoking, drinking, hypertension and other factors, in the co-dominant model, compared with GGgenotype, the risk of NIHL was higher in rs1002149 GT genotype and rs2251780 GA genotype (OR=1.558, 95%CI: 1.028-2.361; OR=1.550, 95%CI: 1.020-2.355, P<0.05) ; compared with TT/GT genotype, the rs1002149 TT genotype has a higher risk of developing NIHL (OR=1.494, 95%CI: 1.002-2.228, P<0.05) , while rs3779647 genotype had no relationship with the risk of NIHL (P>0.05) . In the equivalent sound level (L(Aeq)) of noise >85 dB (A) stratification, compared with GG genotype, carrying rs1002149 GT genotype and rs2251780 GT genotype has higher risk of nihl (OR=1.801, 95%CI: 1.093-2.967; OR=1.720, 95%CI: 1.050-2.817, P<0.05) . Haplotype analysis of two sites, rs1002149 and rs2251780, was not found to be related to NIIHL susceptibility. Conclusion: The allele G of rs1695 and rs6591256 may be risk factors of NIHL.

[Relationship research among CDH23 gene and the risk of noise-induced hearing loss]

Objective: To explore the relationship among CDH23 gene variation and the risk of noise-induced hearing loss (NIHL) . Methods: The nested case-control study was performed and this study followed a cohort of 6297 noise-exposed workers in a steel factory of Henan province in China from January 1, 2006 to December 31, 2015. In July 2019, subjects whose average hearing threshold were more than 40 dB in high frequency were defined as the case group, and subjects whose average hearing threshold were less than 35 dB in high frequency and less than 25 dB in speech frequency were defined as the control group. A nested case-control study which included 572 subjects was carried out, in which subjects consisted of 286 cases and 286 controls. 18 single nucleotide polymorphisms (SNPs) in CDH23 were selected and genotyped, then we analyzed the association among SNPs in CDH23, haplotypes in CDH23 and NIHL risk. Logistic regression was performed to analyze the main effects of SNPs and the interactions between CNE and SNPs adjusting cumulative noise exposure (CNE) , smoking, drinking, physical exercise and hypertension. Moreover, the association between haplotypes in CDH23 and NIHL risk were also analyzed. We ananlyzed the relationship amongst different SNP groups and NIHL risk using the generalized multifactor dimensionality reduction (GMDR) method. Results: The results suggested that significant associations were observed for rs3802711, rs3752751, rs3752752, rs11592462, rs10762480, rs3747867 for NIHL overall and/or various CNE strata by adjusting CNE, smoking, drinking, physical exercise and blood pressure. For rs3802711, workers exposure to noise carrying the AA/GA genotype of rs3802711 increased risk of NIHL than those carrying GG genotype (OR=3.121; 95%CI:1.054-9.239, P=0.035) in overall; In the stratified analysis of CNE (>97 dB (A) ·year at rs3802711 locus, workers exposure to noise carrying GA genotype (OR=2.056; 95%CI:1.226~3.448, P=0.006) and GA+AA/GA genotype (OR=2.221; 95%CI:1.340~3.681, P=0.002) increased NIHL risk. For rs11592462, workers exposure to noise carrying the GG genotype of rs11592462 increased risk of NIHL than those carrying CC genotype in overall (OR=3.951; 95%CI:1.104-14.137, P=0.04) ; workers exposure to noise carrying the GG genotype of rs11592462 increased risk of NIHL than those carrying CG+CC genotype in overall (OR=4.06; 95%CI:1.145-14.391, P=0.03) . After adjusting CNE, smoking, drinking, physical exercise and blood pressure, the haplotypes of CDH23 rs1227049, rs10999947, rs3752752, rs3752751, rs10762480, rs3802711, rs11592462, rs10466026, rs4747194, rs4747195 were not associated with the risk of NIHL. GMDR analysis showed no association between SNP combination and NIHL risk after adjusting CNE, smoking, drinking, physical exercise and blood pressure. Conclusion: Gene polymorphisms in CDH23 might associate significantly with the risk of NIHL.

[Association between GPX1 gene polymorphisms and noise-induced hearing loss]

Objective: To identify association between genetic polymorphism in the Glutathione peroxidase 1 gene (GPX1) and noise-induced hearing loss (NIHL) . Methods: A nested case control study was conducted based on a cohort of noise-exposed subjects. 392 cases were selected from the steel factory in Henan Province, 392 matched control subjects for each case were designated on the basis of the matched criterion including same gender, age (±5years) and duration of exposure to noise (±2years) . Two single nucleotide polymorphisms (SNPs) of GPX1 were genotyped by SNPscanTM multiplex SNP genotyping kit. Hardy-Weinberg equilibrium (HWE) tests were performed using Pearson's χ(2) for each SNP among control group, effects of genotypes of GPX1 on NIHL were analyzed by logistic regression. Results: All two SNPs were in HWE. After adjustment for covariates including smoking status, rs1987628 polymorphism was statistically significantly associated with the NIHL risk under codominant and Dominant inheritance models; In the subjects carrying rs1987628 GA genotype had a higher NIHL risk than those carrying the GG genotype, the adjusted OR value was 1.803 (95%CI 1.215-2.676, P=0.003) . And meanwhile, rs1987628 GA+AA genotype had a higher NIHL risk than those carrying the GG genotype, the adjusted OR value was 1.762 (95%CI 1.197-2.593, P=0.004) . Conclusion: It was suggested that genetic polymorphism in the GPX1 gene might be the genetic susceptible factor for NIHL.

[Association between GSTP1 gave polymorphisms and susceptibility to noise-induced hearing loss]

Objective: To investigate the association between the single nucleotide polymorphisms (SNPS) at rs1695 and rs6591256 in glutathione S-transferase P1 (GSTP1) gene and susceptibility to noise-induced hearing loss in Chinese Han workers exposed to noise. Methods: A 1: 2 matched nested case-control study was performed, which based on the cohort of 6297 workers exposed to noise in an iron and steel plant in Henan, China, who were followed up from January 1, 2006 to December 31, 2015. According to the criteria of binaural average high-frequency hearing threshold ≥40 dB, a total of 292 workers were enrolled as hearing loss group; after the adjustment for sex, type of work, age (difference≤5 years) , and working years of noise exposure (difference≤2 years) , according to the criteria of binaural average high-frequency hearing threshold <35 dB, and the speech frequency hearing threshold of any ear at any frequency band ≤25 dB, a total of 584 workers were enrolled as control group. The single nucleotide polymorphisms (SNPs) of rs1695 and rs6591256 in GSTP1 were genotyped by high throughput SNP genotyping assay. Hardy-Weinberg equilibrium of control group was checked. The association between the SNPs at the two loci and susceptibility to NIHL was analyzed. Results: The L(Aeq, 8 h) range of workers exposed to noise was 80.2-98.8 dB (A) . The risk of NIHL in individuals with allele G of rs1695 was 1.291 times of those with allele A (95%CI: 1.042-1.598, P<0.05) . The risk of NIHL in individuals with allele G of rs6591256 was 1.390 times of those with allele A (95%CI: 1.119-1.728, P<0.05) . The risk of NIHL in individuals with AG and GG genotypes of rs6591256 was 1.437 times of those with AA genotype (95%CI: 1.057-1.952, P<0.05) . With the increase of noise exposure duration, individuals with AG and GG genotypes of rs6591256 had a higher risk of NIHL than those with AA genotype (HR=1.273, 95%CI: 1.002-1.616, P<0.05) . Conclusion: The allele G of rs1695 and rs6591256 may be risk factors of NIHL.

Atomic-Scale Insights into the Dynamics of Growth and Degradation of All-Inorganic Perovskite Nanocrystals

An understanding of growth and degradation pathways is significant to solve the problem of the structural instability of all-inorganic perovskite nanocrystals (NCs). However, it is still a great challenge to directly record such dynamic processes with high spatial resolution owing to the existence of complex internal factors even using in situ transmission electron microscopy observation. Here, we employ a glassy matrix to produce CsPbBr₃ NCs to ensure that the growth and degradation processes of CsPbBr₃ NCs are recorded in the vacuum chamber, which could avoid the influence of the external factors, under electron beam (E-beam) irradiation. In addition, two stages of degradation pathways induced by the E-beam are observed sequentially: (1) a layer-by-layer decomposition and (2) instantaneous vanishing once the radius reaches the critical radius (∼2.3 nm). Indeed, we demonstrated that defects serve as a key flash point that could trigger the structural collapse of CsPbBr₃ NCs. Our findings provide critical insights into the general instability issue of all-inorganic perovskite NCs in practical applications.

Deep UV random lasing from NaGdF4:Yb3+,Tm3+ upconversion nanocrystals in amorphous borosilicate glass

The realization of lanthanide-doped upconversion nanocrystals embedded in a robust and transparent solid medium is highly desired to achieve deep UV (<300nm) lasing. Here, we fabricate NaGdF₄:Yb³⁺,Tm³⁺ upconversion nanocrystals inside amorphous borosilicate glass to support ∼290nm random lasing emission under 980 nm excitation. We found that with careful control of the growth process, which is the key to achieve high-crystallinity nanocrystals, the nanocrystals can suppress defect-related quenching and enhance ¹I₆→³H₆(⁶I_J→⁸S_7/2) transition of Tm³⁺ (Gd³⁺) ions under five-photon absorption excitation so that high optical gain (>45cm^-1) at ∼290nm can be obtained.

Enhanced laser speckle optical sensor for in situ strain sensing and structural health monitoring

In this Letter, an enhanced laser speckle optical sensor (LSOS) for nondestructive, noncontact, and high-accuracy strain measurement has been developed. Subsystems of laser beam shaping and telecentric imaging were incorporated into the LSOS to achieve optimized speckle patterns, and a field-of-view (FOV) separation was introduced to extend sensor gauge length. Validation tests confirmed that the LSOS achieved consistent results with resistive strain gauges in laboratory conditions with maximum RMS error (RMSE) of $ 9.44\;\unicode{x00B5} \unicode{x03B5} $9.44µε. Sensing practicality was demonstrated in field tests. The results showed that the LSOS is capable of achieving accurate strain measurements in an external environment with maximum RMSE of $ 13.34\;\unicode{x00B5}\unicode{x03B5} $13.34µε.

[Determination of nitrogen oxides in the air of workplace by ion chromatography]

Objective: Improvement the method of nitrogen oxide sampling, analysis and detection in workplace air. Methods: Absorption and collection with sodium carbonate-sodium bicarbonate buffer solution, analysised by ion chromatography, anion column AS23, column temperature 30 ℃. Results: The linearity of the nitrite ion in the corresponding mass concentration range 0~90.0 μg/ml was good (Nitrogen dioxide in 0~120.0 mg/m(3)) , correlation coefficient>0.999 5. The detection limit was 0.16 μg/ml, The minimum detection concentration was 0.11 mg/m(3) with the sampling volume 7.5 L. Conclusion: The method has good accuracy, high sensitivity, with directing injection and no pre-treatment, and can popularize in general laboratories, and can satisfy the determination of nitrogen oxides in the air of workplace.

[Study on safety of adjuvant radiotherapy concurrent with weekly chemotherapy for stage ⅡB-ⅣA esophageal carcinoma after radical resection]

Objective: To evaluate the tolerability and short-term efficacy of chemo-radiotherapy in 125 patients with stage ⅡB-ⅣA esophageal carcinoma after radical resection. Methods: We retrospectively evaluated the rate of completion, toxicity and survival of patients undergoing adjuvant concurrent chemo-radiotherapy after radical resection of esophageal carcinoma from January 2004 to December 2014 in our institution. The survival rate was determined by the Kaplan-Meier method and analyzed using the log-rank test. Multivariate prognostic analysis was performed using the Cox proportional hazard model. Results: 122 patients received more than 50 Gy dose (97.6%). A total of 52 patients received more than 5 weeks chemo-radiotherapy (41.6%), while 73 patients underwent only 1-4 weeks (58.4%). The median following up was 48.4 months. 8 patients lost follow up (6.4%). The 1-year and 3-year overall survival rate were 91.6% and 57.0%, respectively, with a median survival time of 64.4 months. The 1-year and 3-year disease free survival rate were 73.2% and 54.3%, respectively, with a median disease free survival time of 59.1 months. The most common acute complications associated with chemo-radiotherapy were myelosuppression, radiation esophagitis and radiation dermatitis, the majority of which were Grade 1-2. Of the 125 patients, there were 59 cases of recurrence, including 23 cases with local regional recurrence, 26 cases with hematogenous metastasis, and 8 cases with mixed recurrence. Univariate analysis showed that the numbers of concurrent chemotherapy was associated with the overall survival (P=0.006). But receiving more than 5 weeks was not the prognostic factor compared to 1 to 4 weeks chemotherapy (P=0.231). Multivariate analysis showed that only the numbers of concurrent chemotherapy was an independent prognostic factor (P=0.010). Conclusions: Postoperative radiotherapy concurrent with weekly chemotherapy could improve the overall survival and decrease the recurrence for stage ⅡB-ⅣA esophageal carcinoma after radical resection. However, the completion rate of chemotherapy was low, so it was necessary to explore reasonable regimens to improve the completion rate and carry out prospective randomized controlled trial.

Highly efficient and ultra-narrow bandwidth orange emissive carbon dots for microcavity lasers

Luminescent materials with high efficiency, narrow emission bandwidth and long emission wavelength have attracted extensive attention in recent years. However, for novel luminescent carbon dots, it is still a major challenge to obtain these properties simultaneously. Here, this type of carbon dot was proposed using 1,4-diaminonaphthalene as the initial source. The carbon dots demonstrate strong orange emission with the highest quantum yield of 82% and an extremely narrow emission bandwidth of 30 nm. It is found that the orange emission of carbon dots is attributed to the high defect amounts including nitrogen and oxygen doping. The high carboxyl group content leads to a high efficiency and the uniform size distribution results in a narrow bandwidth. The carbon dots are used as the gain medium of a whispering gallery mode microcavity laser. A low excitation threshold of 12 kW cm-2 and a high quality factor of ∼3600 can be obtained from the microcavity lasers. This work has provided a didactic example to develop high-quality long emission-wavelength carbon dots with strong emission and an ultra-narrow emission bandwidth, which makes it possible to expand the application of original and high-performance lasers or other optical devices.

[Expression and clinical significance of SSH1 in gastrointestinal stromal tumors]

Objective: To investigate the correlations between the expression of the slingshot-1(SSH1) and the general clinicopathological factors in gastrointestinal stromal tumor (GIST) patients. Methods: Immunohistochemical staining was used to detect the expression of SSH1 protein in 96 gastrointestinal stromal tumors, and the correlations between expression level of SSH1 and general clinicopathological factors were analyzed. Results: Totally, there were 96 cases of GIST patients (49 males and 47 males), with a mean age of (55.80±12.33) years. The tumors were located in different organs: 62 cases (64.6%) in the stomach, 29 cases (30.2%) in the intestine, and 5 cases (5.2%) in other organs, with a mean tumor size of (5.11±3.73) cm. The low risk group contained 57 cases (59.4%), 18 cases (18.8%) in middle risk group and 21 cases (21.9%) in high risk group. The pathological examination showed that the positive expression rate of CD117, CD34, DOG-1, Ki-67, SMA, S-100 and Desmin was 85.4%, 84.4%, 86.5%, 90.6%, 10.4%, 3.1% and 2.1%, respectively. In 96 cases of GIST, 37 cases (38.5%) had high expression of SSH1, and SSH1 expression level was correlated with the tumor invasion depth, risk classification, tumor mitotic figure count, CD34(+) (P<0.05). Conclusions: SSH1 plays an important role in the development of GIST. High expression of SSH1 is closely related to the invasion depth, risk classification and tumor mitosis of GIST.

[Self-esteem and Occupational Stress Relationship Analysis of 1413 Train Drivers in a Railway Bureau]

Objective: To investigate self-esteem status of train drivers. Methods: By using cluster sampling method, a cross-sectional study was conducted in 1 413 train drivers (including passenger train drivers 301, freight train drivers683, passenger shunting train drivers350, and high speed train drivers79) from a railway bureau. The occupational stressors, strains, self-esteem and personalities were measured using occupational stress instruments and effort-reward imbalance questionnaire. Results: The level of self-esteem is medium ofthe train drivers. Sself-esteem scores among different among different job category (job title) , marry status, age, length of service groups were statistical significance (P<0.01) . Differences of self-esteem among different educational level, exercise, smoking and drinking groups weren't statistical significance (P>0.05) . Correlation analysis revealed that self-esteem score was related positively to job satisfaction (r=0.300) , reward (r=0.842) , working stability (r=0.243) , promotion opportunities (r=0.493) , positive affectivity (r=0.216) , responsibility for human beings (r=0.112) and responsibility for things scores (r=0.108) (P<0.01) , negatively to sleep quality (r=-0.103) , social support (r=-0.212) , role conflict (r=-0.007) , role ambiguity (r=-0.169) , physiological needs (r=-0.115) , daily stress (r=-0.150) , negative affectivity (r=-0.252) , depressive symptoms scores (r=-0.215) (P<0.01) . Nonparametric test found that train drivers of group with low self-esteem score reported higher scores for physiological need, role conflict, role ambiguity, social sleep quality, depressive symptoms, negative affectivity, social support and daily stress scores than the medium and higher groups (P<0.01 or<0.05) . But reword, job satisfaction, positive affectivity, copping stratgy, working stability and promotion opportunities scores were lower than the group of medium and higher groups (P<0.01) . Inter-group conflict scores were insignificance (P>0.05) . Multivariate logistic regression analysis revealed that low low self-esteem for drivers occured the risk of job dissatisfaction about 1.5 times as high as that of drivers with higher self-esteem (OR=1.476) Conclusion: Different types of locomotive drivers get different level of self-esteem. Self-esteem was affected by occupational stress largely.

[Determination of p-Anisidine in workplace air by HPLC]

Objective: To establish an HPLC method for determining p-Anisidine in workplace air. Methods: An C(18) capillary column was used with the detection wavelength of 240 nm, the methanol solution (v/v=62:38) as mobile phase, the flow rate was 0.9 ml/min, and the injection volume was 20 μl. Results: The linear range (μg/ml) for p-Anisidine was 0~100; correlation coefficient was 0.999 7; the detection limit was 0.15 μg/ml; the average precision of RSD was 4.4%. The sampling efficiency was more than 95% using silicone tube as sampling filter. Sample can be stored at room temperature for more than 7 d. Conclusion: the method appered to be accurate, simple, sensitive and reliable, also have a high sampling efficiency, and can be usd to determine p-anisidine in workplace air simultaneously.

[Sleep quality and occupational stress relationship analysis of 1413 train drivers in a railway bureau]

Objective: To investigate sleep quality status of train drivers. Methods: By using cluster sampling method, a cross-sectional study was conducted in 1413 train drivers (including passenger train drivers 301, freight train drivers 683, passenger shunting train drivers 350, and high speed train drivers 79) from a railway bureau. The occupational stressors, strains, personalities and sleep quality were measured using occupational stress instruments and effort-reward imbalance questionnaire. Results: The train drivers of poor sleep quality was 48.34%. Sleep quality scores among different among different job category (job title) , exercise, smoking and drinking were statistical significance (P<0.01) . Differences of sleep quality among different educational level, marry status, age, length of service groups weren't statistical significance (P>0.05) . Correlation: analysis revealed that sleep quality score was related negatively to job satisfaction, reward, working stability, promotion opportunities, positive affectivity, esteem and self-esteem scores (r: -0.454, -0.207, -0.329,-0.170, -0.291, -0.103, -0.139, P<0.01 or P<0.05) , positively to social support, effort, role conflict, conflict between groups, conflict in groups, responsibility for person, responsibility for thing, psychological needs, physiological needs, daily stress, negative affectivity, depressive symptoms scores (r: 0.338, 0.524, 0.226, 0.094, 0.182, 0.210, 0.247, 0.190, 0.615, 0.550, 0.345, 0.570, P<0.01) . Nonparametric test found that train drivers of group with high sleep quality score reported higher scores for physiological need, psychological need, effort, role conflict, conflict between groups, social support, daily stress, depressive symptoms, responsibility for person, responsibility for thing, negative affectivity and coping scores than the group of lower sleep quality score (P<0.01) . But reword, job satisfaction, positive affectivity, self-esteem working stability and Promotion opportunities scores were lower than the group of lower sleep quality score (P<0.01) . Multivariate logistic regression analysis revealed the risk for more physiological needs, more effort, more depressive symptoms and more daily stress for drivers occured the risk of poor sleep quality were more than two times as high as that of drivers with less physiological needs, less effort, less depressive symptoms and less daily stress (OR=2.905~2.005) . Conclusions Different types of locomotive drivers get different level of sleep quality. Sleep quality was affected by occupational stress largely. Reducing the occupational stress may contribute to improve the sleep quality of train drivers.

[Change of occupational stress from 1996 to 2012 among train engine drivers]

Objective: To analyze the change of level of occupational stress between 1996 and 2012 among train engine drivers. Methods: the cross-section investigation was conducted by using cluster sampling method, subjects included 1 116 and 1 002 passenger train engine drivers and freight train engine drivers respectively in 1996 and in 2012;occupational stressors, strains, personalities, buffering factors and individual factors were investigated by using Occupational Stress Instruments. Unconditional logistic regression analyses were performed to estimate the associations between job stressors, personalities, buffering factors and individual factors and strains. Multivariate OR(95%CI) were derived from the logistic regression models. Results: From 1996 to 2012, for the passenger train engine drivers the scores of role ambiguity (17.67±5.30 vs.14.11±4.66) increased 25.32%, mental load (10.41±3.56 vs. 16.29±2.08) and physical environment (3.61±2.18 vs. 7.03±1.65) scores decreased 36.10% and 48.64% respectively, sleep disorders (18.04±9.20 vs. 13.35±4.00) and negative affectivity (2.76±1.86 vs. 2.14±1.86) scores increased 33.14% and 28.97% respectively, the differences were statistical significant (P<0.001) . For the freight train engine drivers the scores of sleep disorders (20.33±8.17 vs. 12.47±4.12) and negative affectivity (2.95±1.70 vs. 1.87±1.81) scores increased 57.75% and 60.03% respectively, positive affectivity (2.17±1.60 vs. 2.91±1.50) score decreased 25.43%, the differences were statistical significant (P<0.001) . In general, scores varies in factors related to occupational stress among freight train engine drivers were larger than those among passenger train engine drivers. The risk factor of job dissatisfaction among passenger train drivers in 1996 was insufficient superior support (OR=3.77, 95%CI: 2.23-6.37) , the risk factors in 2012 were insufficient superior support (OR=3.35, 95%CI:1.56-7.17) , poor physical environment (OR=3.61, 95%CI: 1.91-6.80), and fewer positive affectivity (OR=3.47, 95%CI: 1.75-6.82). The risk factor of job dissatisfaction among freight train drivers in 1996 and in 2012 were insufficient superior support (OR (95%CI) were 3.11 (2.31-4.19), 2.59 (1.84-3.65) , respectively). Conclusion: The level of occupational stress among train engine drivers in 2012 was larger than that in 1996, the level of occupational stress among freight train drivers was larger than passenger train drivers, the interventions aimed at reducing occupational stress in the Chinese train engine drivers should take into account promotion for design of job organization and contents and organization management style.

Multiphoton Upconversion Emission from Diamond Single Crystals

Room-temperature upconversion emission up to eight-photon absorption is demonstrated from diamond single crystals under femtosecond laser excitation for the first time. The low concentration of defects and impurities is attributed to the support of free excitons emission at 235 nm. Nonlinear optical properties are also investigated by using an open-aperture Z-scan technique. The corresponding three-, five-, and eight-photon absorption coefficients of the diamonds are found to be 1.8 × 10^-2 cm³/GW², 5 × 10^-9 cm⁷/GW⁴, and 1.6 × 10^-19 cm¹³/GW⁷, respectively. Considering its high hardness and high thermal conductivity, diamonds are a versatile nonlinear optical material suitable for high-power deep ultraviolet applications under multiphoton excitation.

Frequency upconverted amplified spontaneous emission and lasing from inorganic perovskite under simultaneous six-photon absorption

Multiphoton pumped stimulated emission requires simultaneous absorption of photons for the creation of population inversion to sustain optical amplification. Recently, stimulated emission by simultaneous absorption of up to five photons has been realized. To achieve more diverse nonlinear optical applications, it is desired to have more photons involved in the upconversion process. Here, we demonstrate unambiguously frequency upconverted amplified spontaneous emission and lasing via simultaneous six-photon absorption from inorganic perovskite. Our finding allows the utilization of inorganic perovskite as the novel alternative for higher-order multiphoton fluorescent applications.

[Current status of hearing loss and related influencing factors in workers with noise exposure in refining and chemical industry]

Objective: To investigate the current status of hearing loss and related influencing factors in workers with noise exposure in refining and chemical industry. Methods: From August 2015 to March 2016, the investigation method of collecting the data of past occupational health examinations and measuring noise in working environment was used to enroll 8 672 male workers. Results: Of all workers, 11.6% were diagnosed with hearing loss. There were significant differences in the distribution of hearing impairment among workers exposed to noise at different ages, device types and types of work (χ(2)=17.80, 77.80 and 30.53, all P<0.05) . The level of noise exposure≥85 dB (A) (OR=5.79, 95%CI 3.70-8.81) , working years with noise exposure (OR=1.57, 95%CI 1.05-2.43) , and 25 years (OR=3.29, 95%CI 2.08-5.71) were risk factors for hearing loss in workers with noise exposure in refining and chemical industry. Conclusion: The level of noise exposure and working years with noise exposure are main influencing factors for hearing loss in workers with noise exposure in refining and chemical industry.

[Association between single nucleotide polymorphismsin human heat shock protein 70 gene and susceptibility to noise-induced hearing loss]

Objective: To investigate the association between the single nucleotide polymorphisms (SNPs) at rs1043618, rs2075800, and rs2763979 in human heat shock protein 70 (HSP70) gene and susceptibility to noise-induced hearing loss (NIHL) . Methods: A case-control study was performed, and 5 934 workers exposed to noise in an iron and steel plant in Henan, China, who underwent physical examination from 2006 to 2015, were enrolled as study subjects. According to the criteria of binaural average high - frequency (3000, 4000, and 6000 Hz) hearing threshold≥40 dB (HL) and monauralaverage speech-frequency (500, 1000, 2000 Hz) hearing threshold≥26 dB (HL) on the basis of binauralhigh frequency loss measured by pure tone audiometry, as well as the exclusion of NIHL, a total of 286 workers were enrolled as hearing loss group; after the adjustment for sex, type of work, age (difference≤5 years) , and working years of noise exposure (difference ≤2 years) , 286 workers were enrolled as control group. A 2 ml blood genomic DNA extraction kit was used to perform DNA extraction for the peripheral blood samples, and a multiple SNP typing kit was used to determine the genotypes at the three loci in 572 samples. The association between the SNPs at the three loci and susceptibility to NIHL was analyzed. Results: In all workers, the equivalent sound level (L(Aeq)) of noise was 75.0~96.8 dB (A) . The hearing loss group had a significantly higher binauralhigh - frequencyhearing threshold than the control group (t=56.908, P<0.05) . With CC+TC genotype as control, TT genotype at rs2763979 in HSP70 gene was associated with the susceptibility to NIHL (OR=1.731, 95%CI 1.021-2.935) . In the group with cumulative noise exposure of 96 dB (A) ·year, TT genotype at rs2763979was associated with the susceptibility to NIHL (OR=5.694, 95%CI 1.256-25.817) . The rs1043618 and rs2075800 loci of HSP70 were not associated with the susceptibility to NIHL (both P>0.05) . After the adjustment for confounding factors including smoking and drinking, haplotype CCT was associated with the susceptibility to NIHL (OR=1.425, 95%CI 1.035-1.961) . Conclusion: TT genotype at rs2763979 of HSP70 gene and haplotype CCT are risk factors for NIHL.

Direct Identification of Surface Defects and Their Influence on the Optical Characteristics of Upconversion Nanoparticles

Core-shell structure is an obvious concept to suppress surface-related deactivations in lanthanide-doped upconversion nanoparticles (UCNPs). However, no direct observation of atomic-scale surface restoration, which can improve the upconversion photoluminescence, has been reported. Here, we use aberration-corrected high-angle annular dark field scanning transmission electron microscopy to study the surface condition of KLu₂F₇:Yb³⁺,Er³⁺ bare core UCNPs. Due to the very thin and uniform thickness of the UCNPs, we observe unambiguously that the recovery from surface defects enhances upconversion photoluminescence. Furthermore, the realization of dominant green lasing emission under pulsed laser excitation confirms the high crystallinity of the UCNPs.

[Association of etheno-DNA adduct and DNA methylation level among workers exposed to diesel engine exhaust]

Objective: To investigate the association between etheno-DNA adduct and the promoter of DNA methylation levels of cyclin dependent kinase inhibitor 2A (P16), Ras association domain family 1 (RASSF1A) and O-6-methylguanine-DNA methyltransferase (MGMT) in workers with occupational exposure to diesel engine exhaust (DEE). Methods: We recruited 124 diesel engine testing workers as DEE exposure group and 112 water pump operator in the same area as control group in Henan province in 2012 using cluster sampling. The demographic data were obtained by questionnaire survey; urine after work and venous blood samples were collected from each subject. The urinary etheno-DNA adducts were detected using UPLC-MS/MS, including 1,N6-etheno-2'-deoxyadenosine (εdA) and 3,N4-etheno-2'-deoxycytidine(εdC). The DNA methylation levels of P16, RASSF1A, and MGMT were evaluated using bisulfite-pyrosequencing assay. The percentage of methylation was expressed as the 5-methylcytosine (5mC) over the sum of cytosines (%5mC). Spearman correlation and multiple linear regression were applied to analyze the association between etheno-DNA adducts and DNA methylation of P16, RASSF1A, and MGMT. Results: The median (P(25)-P(75)) of urinary εdA level was 230.00 (98.04-470.91) pmol/g creatinine in DEE exposure group, and 102.10 (49.95-194.48) creatinine in control group. The level of εdA was higher in DEE exposure group than control group (P<0.001). DNA methylation levels of P16, RASSF1A and MGMT were 2.04±0.41, 2.19 (1.94-2.51), 2.22 (1.94-2.46)%5mC in exposure group, and 2.19±0.40, 2.41 (2.11-2.67), 2.44 (2.15-2.91)%5mC in control group. DNA methylation levels were lower in exposure group (P values were 0.005, 0.002 and 0.001, respectively). Spearman correlation analysis showed that DNA methylation levels of P16, RASSF1A, and MGMT were negative associated with urinary εdA level (r values were -0.155, -0.137, and -0.198, respectively, P<0.05). No significant correlation was observed between the εdC level and any measured DNA methylation levels (P>0.05) . Multiple linear regression confirmed the negative correlation between εdA and DNA methylation levels of P16, RASSF1A, and MGMT in non-smoking group (β (95%CI) was -0.068 (-0.132--0.003), -0.082 (-0.159--0.004) and -0.048 (-0.090--0.007), P values were 0.039, 0.039 and 0.024, respectively). Moreover, εdC was negative associated with DNA methylation level of MGMT in non-smoking group (β (95%CI) was -0.094 (-0.179--0.008), P=0.032). Conclusion: DEE exposure could induce the increased of εdA and decreased of DNA methylation levels of P16, RASSF1A and MGMT.