Background: Emotional labor, the management of feelings to create organizationally desired emotional displays, has been consistently associated with adverse health outcomes in Western populations. However, cultural context may fundamentally alter these relationships in Asian service economies. Objectives: To examine temporal trends in emotional labor prevalence and investigate associations between emotional labor and health outcomes among Korean service workers over a 17-year period. Design: Repeated cross-sectional study. Methods: We analyzed data from seven waves of the Korean Working Conditions Survey (2006-2023), comprising 271,039 observations. Emotional labor was assessed using validated items measuring frequency of hiding feelings and managing customer emotions. Health outcomes included psychological symptoms (depression, anxiety, fatigue) and physical symptoms (musculoskeletal disorders, headaches, gastrointestinal problems). We employed multivariable logistic regression, fixed-effects models, and mediation analyses, adjusting for sociodemographic and occupational factors. Results: Emotional labor exposure remained stable at approximately 3.0 (5- point scale) from 2014-2023. Health problem prevalence was consistently around 60% across all survey years. Contrary to hypotheses, emotional labor showed no significant association with health problems (OR=0.999, 95% CI: 0.993-1.005, P=0.735). These null findings persisted in fixed-effects analyses (β=-0.0003, P=0.736), gender-stratified models, and interaction tests. The Cochran-Armitage trend test revealed no temporal trends (P=0.865). Mediation analysis found no indirect effects through psychological hazards. Notably, this finding represents a paradoxical discovery that challenges Western-centric assumptions about the universality of emotional labor's health effects. Conclusion: Despite high statistical power and comprehensive methodology, we found no evidence linking emotional labor to health problems in Korean workers. These unexpected findings challenge the assumed universality of emotional labor's health effects and suggest cultural factors may fundamentally modify occupational stress pathways. Western-derived theoretical models may require substantial adaptation for Asian contexts where emotional regulation represents normative social behavior rather than occupational burden.

The high theoretical capacity of transition metal-based compounds makes them promising candidates for lithium-ion battery (LIB) anodes. Among them, iron selenide (FeSe2) has attracted considerable interest because of its excellent electrical conductivity and superior lithium storage capacity. However, pristine FeSe2 suffers from rapid capacity fading and structural instability during repeated cycling. Thus, this study used a facile solvothermal method to synthesize a FeSe2@rGO composite with enhanced structural integrity and electrical conductivity. By incorporating reduced graphene oxide (rGO), the composite demonstrated improved charge transfer kinetics and mechanical robustness. Morphological and structural characterizations were performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy analyses (XPS), which confirmed the successful formation of the composite and its uniform distribution. Electrochemical properties were evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge, long-term cycling, and electrochemical impedance spectroscopy. The optimized FeSe2@rGO electrode delivered a high reversible capacity of 971.95 mAhg-1 at 500 mAg-1 after 350 cycles. The underlying charge storage mechanism was investigated using scan rate-dependent CV, which revealed a dominant capacitivecontrolled contribution at higher scan rates. The study findings indicate that the FeSe2@rGO composite can serve as a high-performance anode material with excellent cycling stability and rate capability, providing a viable strategy for the development of advanced LIBs.

All-solid-state lithium batteries (ASSLBs) are receiving attention as a prospective next-generation secondary battery technology that can reduce the risk of commercial lithium-ion batteries by replacing flammable organic liquid electrolytes with non-flammable solid electrolytes. The practical application of ASSLBs requires developing robust solid electrolytes that possess ionic conductivity at room temperature on a par with that of organic liquids. These solid electrolytes must also be thermally and chemically stable, as well as compatible with electrode materials. Inorganic solid electrolytes, including oxide and sulfide-based compounds, are being studied as promising future candidates for ASSLBs due to their higher ionic conductivity and thermal stability than polymer electrolytes. Here, we present the challenges currently facing the development of oxide and sulfide-based solid electrolytes, as well as the research efforts underway aiming to resolve these challenges.

Carbon fibers (CFs) are considered promising composite materials for various applications. However, the high cost of CFs (as much as $26 per kg) limits their practical use in the automobile and energy industries. In this study, we developed a continuous stabilization process for manufacturing low-cost CFs. We employed a textile-grade polyacrylonitrile (PAN) fiber as a low-cost precursor and UV irradiation technique to shorten the thermal stabilization time. We confirmed that UV irradiation on the textile-grade PAN fibers could lower the initial thermal stabilization temperature and also lead to a higher reaction. These resulted in a shorter overall stabilization time and enhancement of the tensile properties of textilegrade PAN-based CFs. Our study found that only 70 min of stabilization time with UV irradiation was required to prepare textile-grade PAN-based low-cost CFs with a tensile strength of 2.37 ± 0.22GPa and tensile modulus of 249 ± 5 GPa.

Conductive carbon cloths (CCs) have been great attention as a promising current collector for flexible supercapacitors that supply power to portable and wearable electronics. However, the hydrophobic surface and weak adhesion with active materials has limited to be adopted as the binder-free and flexible electrode with mechanical/electrochemical stability. In this work, we demonstrate preparation of binder-free and flexible electrodes based on polyaniline (PANI) on carbon cloth. Polydopamine (PDA) layer are used to impart hydrophilicity, leading to uniform growth of PANI on the hydrophobic surface of carbon. Furthermore, PDA layer improves adhesion strength between PANI and carbon substrates, which allows for superior mechanical stability under ultrasonic condition. PANI-based flexible electrode shows high areal capacitance (160.8 mF cm− 2 at 0.5 mA cm− 2), good rate capability (71.1% even at high current density of 10 mA cm− 2), and long-term cycling stability (82.6% capacitance retention after 1500 cycles). Furthermore, a quasi-solid-state flexible supercapacitor reveals remarkable mechanical flexibility and durability, with superior capacitance retention (~ 100%) in bent state and after repetitive 1000 cycles.

In this study, multilayered SnO nanoparticles are prepared using oleylamine as a surfactant at 165oC. The physical and chemical properties of the multilayered SnO nanoparticles are determined by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Interestingly, when the multilayered SnO nanoparticles are heated at 400oC under argon for 2 h, they become more efficient anode materials, maintaining their morphology. Heat treatment of the multilayered SnO nanoparticles results in enhanced discharge capacities of up to 584 mAh/g in 70 cycles and cycle stability. These materials exhibit better coulombic efficiencies. Therefore, we believe that the heat treatment of multilayered SnO nanoparticles is a suitable approach to enable their application as anode materials for lithium-ion batteries.

Despite evidence that bacteria-sensing Toll-like receptors (TLRs) are activated in salivary gland tissues of Sjogren syndrome (SS) patients, the role of oral bacteria in SS etiopathogenesis is unclear. We previously reported that two SS-associated oral bacteria, Prevotella melaninogenica (Pm) and Rothia mucilagenosa (Rm), oppositely regulate the expression of major histocompatibility complex class I (MHC I) in human salivary gland (HSG) cells. Here, we elucidated the mechanisms underlying the differential regulation of MHC I expression by these bacteria. The ability of Pm and Rm to activate TLR2, TLR4, and TLR9 was examined using TLR reporter cells. HSG cells were stimulated by the TLR ligands, Pm, and Rm. The levels of MHC I expression, bacterial invasion, and viability of HSG cells were examined by flow cytometry. The hypoxic status of HSG cells was examined using Hypoxia Green. HSG cells upregulated MHC I expression in response to TLR2, TLR4, and TLR9 activation. Both Pm and Rm activated TLR2 and TLR9 but not TLR4. Rm-induced downregulation of MHC I strongly correlated with bacterial invasion and cell death. Rm-induced cell death was not rescued by inhibitors of the diverse cell death pathways but was associated with hypoxia. In conclusion, Pm upregulated MHC I likely through TLR2 and TLR9 activation, while Rm-induced hypoxia-associated cell death and the downregulation of MHC I, despite its ability to activate TLR2 and TLR9. These findings may provide new insight into how oral dysbiosis can contribute to salivary gland tissue damage in SS.