The relationship between occupational dust exposure and incidence of diabetes in male workers: A retrospective cohort study.

AIM: Previous studies have focused on the association between ambient particulate matter and diabetes. However, the relationship between subacute exposure to occupational dust and diabetes has not been explored. We aimed to assess this relationship. METHODS: Men who worked in dust-related process factories between January 2013 and December 2017 were recruited from a Korea Health Worker Examination Common Data Model cohort. A history of physician-diagnosed diabetes, use of an anti-diabetic drug, or a fasting blood glucose level of ≥7 mmol/L were considered the criteria to diagnose diabetes. Multivariable time-dependent Cox analysis estimated hazard ratios (HRs) and 95% CIs for incident diabetes associated with exposure to occupational dust exposure; interactions with lifestyle factors were analysed. Sensitivity analyses used propensity score matching and landmark analysis. RESULTS: Among 5141 male participants (median follow-up duration, 3.85 years), 349 participants had diabetes. Occupational dust exposure was related to an increased risk of diabetes in the time-dependent Cox analysis (entire cohort: HR 1.66 [95% CI 1.25-2.19], matched cohort: HR 1.65 [95% CI 1.22-2.24]). The findings showed the same direction in the landmark analysis (HR 1.42 [95% CI 1.01-1.99]). CONCLUSIONS: A significant relationship exists between occupational dust exposure and increased risk of diabetes in male workers. Further studies should be conducted to confirm that occupational dust exposure is a possible risk factor for diabetes.

Flavobacterium knui sp. nov., a novel member of the family Flavobacteriaceae.

A Gram-stain negative, non-motile, rod-shaped bacterial strain, designated 2-56T, was isolated from water and characterized taxonomically using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain 2-56T belongs to the family Flavobacteriaceae in the phylum Bacteroidetes and is closely related to Flavobacterium paronense KNUS1T (98.4%) and Flavobacterium collinsense 4-T-2T (96.7%). The G + C content of the genomic DNA of strain 2-56T was 33.4 mol%. The isolate contained MK-6 as the predominant respiratory quinone, and iso-C15:1 G (15.9%), iso-C15:0 (15.8%), iso-C17:0 3-OH (10.7%), and iso-C15:0 3-OH (9.6%) were the major fatty acids. The major polar lipids were phosphatidylethanolamine and an unidentified lipid. The phenotypic and chemotaxonomic data support the affiliation of strain 2-56T with the genus Flavobacterium. However, the DNA-DNA relatedness between the isolate and F. paronense and F. collinsense were 35.7 and 21.5%, respectively, clearly showing that strain 2-56T is not related to them at the species level. Strain 2-56T could be clearly differentiated from its close neighbours on the basis of its phenotypic, genotypic and chemotaxonomic features. Therefore, strain 2-56T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium knui sp. nov. is proposed. The type strain is 2-56T (= KCTC 62061T = JCM 32247T).

Clinical Evaluation of Rapid Diagnostic Test Kit for Scrub Typhus with Improved Performance.

Diagnosis of scrub typhus is challenging due to its more than twenty serotypes and the similar clinical symptoms with other acute febrile illnesses including leptospirosis, murine typhus and hemorrhagic fever with renal syndrome. Accuracy and rapidity of a diagnostic test to Orientia tsutsugamushi is an important step to diagnose this disease. To discriminate scrub typhus from other diseases, the improved ImmuneMed Scrub Typhus Rapid Diagnostic Test (RDT) was evaluated in Korea and Sri Lanka. The sensitivity at the base of each IgM and IgG indirect immunofluorescent assay (IFA) in Korean patients was 98.6% and 97.1%, and the specificity was 98.2% and 97.7% respectively. The sensitivity and specificity for retrospective diagnosis at the base of IFA in Sri Lanka was 92.1% and 96.1%. ImmuneMed RDT was not reactive to any serum from seventeen diseases including hemorrhagic fever with renal syndrome (n = 48), leptospirosis (n = 23), and murine typhus (n = 48). ImmuneMed RDT shows superior sensitivity (98.6% and 97.1%) compared with SD Bioline RDT (84.4% at IgM and 83.3% at IgG) in Korea. The retrospective diagnosis of ImmuneMed RDT exhibits 94.0% identity with enzyme-linked Immunosorbent assay (ELISA) using South India patient serum samples. These results suggest that this RDT can replace other diagnostic tests and is applicable for global diagnosis of scrub typhus. This rapid and accurate diagnosis will be beneficial for diagnosing and managing scrub typhus.

Continuous exposure to 60 Hz magnetic fields induces duration- and dose-dependent apoptosis of testicular germ cells.

To evaluate duration- and dose-dependent effects of continuous exposure to a 60 Hz magnetic field (MF) on the testes in mice, BALB/c male mice were exposed to a 60 Hz MF at 100 µT for 24 h a day for 2, 4, 6, or 8 weeks, and at 2, 20, or 200 µT for 24 h a day for 8 weeks. Any exposures to MF did not significantly affect body or testicular masses. However, the apoptotic cells among testicular germ cells were increased duration-dependent at exposures of 100 µT for 6 and 8 weeks and dose-dependent at exposures of 20 and 200 µT for 8 weeks. The number of sperm in epididymis and the diameter of seminiferous tubule decreased in mice exposed to 100 and 200 µT for 8 weeks, respectively. To induce the apoptosis of testicular germ cell in mice, the minimum dose is 20 µT at continuous exposure to a 60 Hz MF for 8 weeks and the minimum duration is 6 weeks at continuous exposure of 100 µT. Taken together, these results suggest that continuous exposure to a 60 Hz MF might affect, duration- and dose-dependent biological processes including apoptotic cell death and spermatogenesis in the male reproductive system of mice.

Nondestructive Single-Atom-Thick Crystallographic Scanner via Sticky-Note-Like van der Waals Assembling-Disassembling.

Crystallographic characteristics, including grain boundaries and crystallographic orientation of each grain, are crucial in defining the properties of two-dimensional materials (2DMs). To date, local microstructure analysis of 2DMs, which requires destructive and complex processes, is primarily used to identify unknown 2DM specimens, hindering the subsequent use of characterized samples. Here, a nondestructive large-area 2D crystallographic analytical method through sticky-note-like van der Waals (vdW) assembling-disassembling is presented. By the vdW assembling of veiled polycrystalline graphene (PCG) with a single-atom-thick single-crystalline graphene filter (SCG-filter), detailed crystallographic information of each grain in PCGs is visualized through a 2D Raman signal scan, which relies on the interlayer twist angle. The scanned PCGs are seamlessly separated from the SCG-filter using vdW disassembling, preserving their original condition. The remaining SCG-filter is then reused for additional crystallographic scans of other PCGs. It is believed that the methods can pave the way for advances in the crystallographic analysis of single-atom-thick materials, offering huge implications for the applications of 2DMs.

Improvement of the diagnostic sensitivity of scrub typhus using a mixture of recombinant antigens derived from Orientia tsutsugamushi serotypes.

Diagnosis of scrub typhus is difficult because its symptoms are very similar to other acute febrile illnesses, such as leptospirosis, murine typhus, and other viral hemorrhagic fevers. To differentiate scrub typhus from other acute febrile diseases, a rapid and reliable serological diagnosis is important. We have developed a chimeric recombinant antigen cr56 and two other recombinant antigens, r21 and kr56, from various serotypes of Orientia tsutsugamushi. They were tested for the detection of antibodies against O. tsutsugamushi in the patient's serum samples using enzyme-linked immunosorbent assay (ELISA) and dot-blot analyses. As of conventional immunofluorescence assay (IFA), when the mixture of these three recombinant antigens was used, both sensitivity and specificity of the recombinant antigens were increased up to 98% in IgM and IgG at ELISA and dot blotting. Additionally, both sensitivity and specificity by detection of IgM and IgG antibodies at rapid diagnostic test (RDT), using the mixture of three antigens and gold conjugated antibodies, were 99%. Our results suggest the use of mixture of these recombinant antigen proteins in ELISA or RDT is suitable as a diagnostic test for scrub typhus.

Association between physical risk factors and sleep disturbance among workers in Korea: The 5th Korean Working Conditions Survey.

OBJECTIVE: Sleep disturbance is associated with negative effects to workers' health and productivity; hence, it is important to find which population of workers are associated with sleep disturbance. This study aimed to investigate the association between physical risk factors (vibration, noise, high, and low temperatures) and sleep disturbance in the Korean working population. METHODS: We analyzed data on 29,213 paid workers from the 5th Korean Working Conditions Survey. Individual and occupational characteristics, physical risk factors exposure, and sleep disturbance were collected using self-reported questionnaires. To assess the association between physical risk factors and sleep disturbance, the chi-square test and multivariable logistic regression models were conducted. All statistical analyses were performed in sex-based subgroups. RESULTS: We observed that all physical risk factors are associated with sleep disturbance. The adjusted odds ratios (95% confidence interval [CI]) of severe exposure to vibration, noise, high and low temperature were 1.69 (CI:1.47-1.94), 2.52 (CI:2.17-2.92), 3.09 (CI:2.69-3.56), and 1.96 (CI:1.68-2.28) in male workers and 2.27 (CI:1.89-2.72), 3.52 (CI:2.92-4.24), 3.30 (CI:2.81-3.87), and 2.87 (CI:2.44-3.38) in female workers, respectively. The prevalence of sleep disturbance increased with increased exposure to physical risk factors, indicating a dose-response relationship. CONCLUSIONS: Physical risk factors exposure in the workplace was associated with sleep disturbance of workers, indicating a dose-response relationship. Given the impact of sleep disturbance on workers' health and efficiency, it may be important to control exposure to physical risk factors in the working environment with regards to sleep conditions.

Secondhand Smoke in the Workplace Is Associated With Depression in Korean Workers.

Background: Smoking negatively affects health, and previous studies argue that secondhand smoke (SHS) has a significantly negative health effect. We investigated whether SHS in the workplace influences workers' depression. Methods: Three years of data (2014, 2016, and 2018) from the Korean National Health and Nutrition Examination Survey were analyzed. Participants who were not current smokers were classified into the occupational SHS exposed and non-exposed groups. Multivariate logistic regression was performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs) by adjusting various covariates. Stratified analysis with variables, such as year, sex, occupational classification, average working hours, was additionally performed. Results: The crude ORs of depression was 1.51 (95% CI: 1.27-1.80), and the fully adjusted OR with all the covariates was 1.57 (95% CI: 1.30-1.88). This indicated a significant relationship between occupational SHS and depression. The ORs increased every 2 years: 1.07 (95% CI: 0.79-1.44) in 2014, 1.88 (95% CI: 1.34-2.64) in 2016, and 2.07 (95% CI: 1.43-2.99) in year 2018. Stratification analysis also showed a significant association between SHS and depression among those in the prolonged work hours group and male employees, as well as blue- and white-collar workers. Conclusion: SHS in the workplace was significantly associated with workers' depression. Our study provides insights into the impact of exposure to SHS for workers and provides a basis for further research and policy-making in this field.

Fracture Resistance of Monolithic Zirconia Crowns Depending on Different Marginal Thicknesses.

Under some clinical conditions, the preparation of crowns of limited marginal thickness is inevitable. In such situations, it is questionable whether the same ideal preparation criteria can be applied equally. Since there are only a small number of studies focusing on the fracture resistance with respect to the marginal thickness, there is a need for a study evaluating whether zirconia crowns of limited marginal thickness are clinically acceptable. The purpose of this study is to evaluate the fracture resistance of monolithic zirconia crowns of limited marginal thickness in the posterior area. Methods: Abutments and CAD/CAM zirconia crowns with a marginal thickness of 1.0 mm were set as the control group, while experimental groups A, B, and C possessed reduced marginal thicknesses of 0.8 mm, 0.6 mm, and 0.4 mm, respectively (n = 10 per group). Resin-based abutment dies and monolithic zirconia crowns were fabricated using the CAD/CAM technique, and a universal testing machine was used to measure the fracture load value. Fractured specimens were examined with a scanning electron microscope. The data were analyzed using a one-way ANOVA and Bonferroni post hoc test (p < 0.05). Results: The means and standard deviations of the fracture load values of the control group and the three experimental groups were as follows: control group (1.0 mm): 3090.91 ± 527.77 N; group A (0.8 mm): 2645.39 ± 329.21 N; group B (0.6 mm): 2256.85 ± 454.15 N; group C (0.4 mm): 1957.8 ± 522.14 N. Conclusions: The crowns fabricated with a CAD/CAM zirconia block with limited marginal thicknesses of 0.6 mm and 0.4 mm showed significantly lower fracture resistance values compared to those with the recommended margin thickness of 1.0 mm.

Does severe subacute noise exposure increase risk of new onset hypertension beyond conventional risk factors? A 30 000 person-years cohort study.

OBJECTIVES: Previous studies mostly focused on the relationship between chronic environmental noise exposure and hypertension but the effects of subacute (under 4 years) exposure with severe (>85 dB) noise exposure on clinical level hypertension have not been explored. This study aimed to reveal the association between severe noise exposure and hypertension. METHODS: The severe noise exposure group was recruited from a Common Data Model conducted for the Korean Participants Health Examination from January 2014 to December 2017. The use of antihypertensive drug and/or blood pressure of at least 140/90 mmHg was defined as new onset clinical hypertension. A multivariate Cox proportional hazard model was implemented to estimate hazard ratios and 95% confidence intervals (CI) by adjusting covariates including demographic, lifestyle, and other chemical exposure factors. Time-dependent Cox analysis and Landmark analysis were further performed as a sensitivity analysis. RESULTS: During the 29 332 person-years follow-up with 12 412 participants of the entire cohort, new onset hypertension occurred in 1222 participants. The findings showed that severe noise exposure was associated with an increased risk of hypertension incidence in the entire cohort [final model hazard ratio 1.28 (95% CI 1.11-1.47)]. Other covariates did not attenuate the association after adjusting age and sex. Time-dependent Cox and Landmark analysis also showed significant results [hazard ratio 1.60 (95% CI 1.38-1.85) and hazard ratio 1.33 (95% CI 1.13-1.57)]. CONCLUSION: Severe noise with subacute exposure is significantly associated with hypertension development. Further studies should be implemented to clarify whether severe exposure to noise could be an important risk factor for hypertension.

Association between Self-Perceived Social Support in the Workplace and the Presence of Depressive/Anxiety Symptoms.

This study aimed to investigate the association of support from colleagues and supervisors at the workplace on depressive and anxiety symptoms in wage earners from Korea. The data used in this study were from the fifth Korean Working Conditions Survey (KWCS) conducted in 2017 and analyzed using a multivariate logistic regression model. Furthermore, we measured the odds ratios (ORs) and 95% confidence intervals (CIs) of depressive and anxiety symptoms by stratifying covariates. The ORs of depressive and anxiety symptoms for the "non-support" group were higher than for the "support group" in terms of support from both colleagues and supervisors. The results of the stratified analysis of covariates, male, young, highly-educated, full-time, and white-collar groups were associated with the lack of support. Support from colleagues and supervisors was significantly associated with the Korean wage worker's mental health-depressive and anxiety symptoms, respectively. Further longitudinal and clinical studies on the relationship between mental health and support at the workplace are required.

Predictors of Positive Video Capsule Endoscopy Findings for Chronic Unexplained Abdominal Pain: Single-Center Retrospective Study and Meta-Analysis.

Video capsule endoscopy (VCE) is an effective diagnostic modality for detecting small bowel lesions. However, the value of VCE for patients with chronic recurrent abdominal pain (CAP) of unknown etiology remains obscure. We retrospectively analyzed factors that could predict enteropathy based on the medical records of 65 patients with unexplained chronic recurrent abdominal pain (CAP) who were assessed using VCE between 2001 and 2021. We also conducted a systematic review and meta-analysis of the literature to validate our results. The positive findings of 27 (41.5%) of the 65 patients were mostly ulcerative lesions including stricture (n = 14, 60.9%) and erosion (n = 8, 29.7%). Multivariate analysis identified elevated ESR (OR, 1.06, 95% CI, 1.02-1.1, p = 0.004) as a significant risk factor for enteropathy predicted by VCE. Three eligible studies in the meta-analysis included 523 patients with CAP. Elevated C-reactive protein (CRP) (OR, 14.09; 95% CI, 2.81-70.60; p = 0.001) and erythrocyte sedimentation rate (ESR) (OR, 14.45; 95% CI, 0.92-227.33; p = 0.06) indicated VCE-positive findings in patients with unexplained abdominal pain. Elevated levels of the inflammatory markers ESR and CRP can thus predict positive VCE findings in patients with CAP.

Occupational Noise Exposure and Incidence of High Fasting Blood Glucose: A 3-Year, Multicenter, Retrospective Study.

The role of hazardous occupational noise exposure on the development of prediabetes is not well researched. We aimed to elucidate exposure to hazardous occupational noise as an independent risk factor for high fasting blood glucose (FBG). Participants exposed/non-exposed to occupational noise were recruited from the Common Data Model cohorts of 2013/2014 from two centers and were followed-up for 3 years. Multivariate time-dependent Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) and were adjusted for various covariates. Pooled HRs were calculated. Among the 43,858 participants of this retrospective cohort study, 37.64% developed high FBG. The mean (standard deviation) age in the cohort was 40.91 (9.71) years. In the fully adjusted models, the HRs of high FBG in the two centers were 1.35 (95% CI: 1.24-1.48) and 1.22 (95% CI: 1.17-1.28), and the pooled HR was 1.28 (95% CI: 1.16-1.41). A Kaplan-Meier plot of high FBG incidence by occupational noise exposure showed significant results (p < 0.001). We found that occupational noise exposure is significantly associated with high FBG. Preventing exposure to hazardous noise in the work environment may help reduce the risk for prediabetes among workers.

The Association Between the Number of Consecutive Night Shifts and Insomnia Among Shift Workers: A Multi-Center Study.

Objectives: There is a need to determine the optimal limit of consecutive night shift work to reduce insomnia caused by the accumulation of sleep problems among night shift workers. This study aimed to investigate the prevalence of insomnia caused by consecutive night shifts and evaluate the night shift duration that worsens insomnia the most, using a large amount of medical examination data. Methods: Night shift profiles and baseline demographics data of three hospitals were collected from January 2015 to December 2017. For subjects who had been examined more than once at the same institution, information corresponding to the most recent date was used. Multivariate logistic regression was performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Pooled ORs were calculated by using the results of the three institutions. Results: Of the 33,669 participants, 31.3% were female. The average age was 41.1 ± 11.1 years and the prevalence of insomnia was 38.7% (n = 13,025). After adjusting for potential confounders and compared to workers who reported not working in consecutive night shifts, odds of insomnia were greatest among workers reporting working three consecutive nights (OR 2.65, 95% CI 1.97-3.56) followed by those working two nights (OR 1.81, 95% CI 1.45-2.26), five nights (OR 1.78, 95% CI 1.56-2.03), and four nights (OR 1.68, 95% CI 1.55-1.82). Conclusion: Our study demonstrates a significant relationship between consecutive night shift and insomnia with multicenter examination data, using common data model. This study could be a basis for establishing policies and guidelines that improve night shift workers' health.

Completely foldable electronics based on homojunction polymer transistors and logics.

An increase in the demand for completely foldable electronics has motivated efforts for the development of conducting polymer electrodes having extraordinary mechanical stability. However, weak physical adhesion at intrinsic heterojunctions has been a challenge in foldable electronics. This paper reports the completely foldable polymer thin-film transistors (PTFTs) and logic gate arrays. Homojunction-based PTFTs were fabricated by selectively doping p-type diketopyrrolopyrrole-based semiconducting polymer films with FeCl3 to form source/drain electrodes. The doping process caused a gradual work function change with depth, which promoted charge injection to semiconducting regions and provided a low contact resistance. In addition, the interfacial adhesion in the PTFTs was improved by interfacial cross-linking between adjacent component layers. The electrical performance of the resulting PTFTs was maintained without noticeable degradation even after extreme folding, suggesting that the proposed fabrication strategy can further be applied to various semiconducting polymers for the realization of foldable electronics.

Stoichiometric Doping of Highly Coupled Cu2-xS Nanocrystal Assemblies.

The hole density of individual copper sulfide nanocrystals (Cu2-xS NCs) is determined from the stoichiometric mismatch (x) between copper and sulfide atoms. Consequently, the electronic properties of the material vary over a range of x. To exploit Cu2-xS NCs in devices, assemblies of NCs are typically required. Herein, we investigate the influence of x, referred to as the stoichiometric doping effect, on the structural, optical, electrical, and thermoelectric properties of electronically coupled Cu2-xS NC assemblies. The doping process is done by immersing the solid NC assemblies into a solution containing a Cu(I) complex for different durations (0-10 min). As Cu+ gradually occupied the copper-deficient sites of Cu2-xS NCs, x could be controlled from 0.9 to less than 0.1. Consequently, the near-infrared (NIR) absorbance of Cu2-xS NC assemblies changes systematically with x. With increasing x, electrical conductivity increased and the Seebeck coefficient decreased systematically, leading to the maximal thermoelectric power factor from a film of Cu2-xS NCs at an optimal doping condition yielding x = 0.1. The physical characteristics of the Cu2-xS NC assemblies investigated herein will provide guidelines for exploiting this emerging class of nanocrystal system based on doping.

Universal three-dimensional crosslinker for all-photopatterned electronics.

All-solution processing of large-area organic electronics requires multiple steps of patterning and stacking of various device components. Here, we report the fabrication of highly integrated arrays of polymer thin-film transistors and logic gates entirely through a series of solution processes. The fabrication is done using a three-dimensional crosslinker in tetrahedral geometry containing four photocrosslinkable azide moieties, referred to as 4Bx. 4Bx can be mixed with a variety of solution-processable electronic materials (polymer semiconductors, polymer insulators, and metal nanoparticles) and generate crosslinked network under exposure to UV. Fully crosslinked network film can be formed even at an unprecedentedly small loading, which enables preserving the inherent electrical and structural characteristics of host material. Because the crosslinked electronic component layers are strongly resistant to chemical solvents, micropatterning the layers at high resolution as well as stacking the layers on top of each other by series of solution processing steps is possible.

High-resolution patterning of colloidal quantum dots via non-destructive, light-driven ligand crosslinking.

Establishing multi-colour patterning technology for colloidal quantum dots is critical for realising high-resolution displays based on the material. Here, we report a solution-based processing method to form patterns of quantum dots using a light-driven ligand crosslinker, ethane-1,2-diyl bis(4-azido-2,3,5,6-tetrafluorobenzoate). The crosslinker with two azide end groups can interlock the ligands of neighbouring quantum dots upon exposure to UV, yielding chemically robust quantum dot films. Exploiting the light-driven crosslinking process, different colour CdSe-based core-shell quantum dots can be photo-patterned; quantum dot patterns of red, green and blue primary colours with a sub-pixel size of 4 µm × 16 µm, corresponding to a resolution of >1400 pixels per inch, are demonstrated. The process is non-destructive, such that photoluminescence and electroluminescence characteristics of quantum dot films are preserved after crosslinking. We demonstrate that red crosslinked quantum dot light-emitting diodes exhibiting an external quantum efficiency as high as 14.6% can be obtained.