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Synbiotics are complex preparations of prebiotics that can be selectively utilized by live microorganisms to improve host health. Synbiotics are divided into complementary synbiotics, which consist of probiotics and prebiotics with independent functions, and synergistic synbiotics, which consist of prebiotics that are selectively used by gut microorganisms. Complementary synbiotics used in human clinical trials include Lactobacillus spp. and Bifidobacterium spp. as probiotics, and fructooligosaccharides, galactooligosaccharides, and inulin as prebiotics. Over the past five years, synbiotics have been most commonly used in patients with metabolic disorders, including obesity, and immune and gastrointestinal disorders. Several studies have observed alterations in the microbial community; however, these changes did not lead to significant improvements in disease outcomes or biochemical and hematological markers. The same synbiotics have been applied to individuals with different gut environments. As a result, even with the same synbiotics, there are non-responders who do not respond to the applied synbiotics due to the different intestinal environment for each individual. Therefore, to obtain meaningful results, applying different synbiotics depending on the individual is necessary. Synergistic synbiotics are one solution to circumvent this problem, as they combine elements that can effectively improve health, even in non-responders. This review aims to explain the concept of synbiotics, highlight recent human clinical trials, and explore the current state of research on synergistic synbiotics., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Aim: To assess the ability of clinical examination, biomarkers, electrophysiology and brain imaging, individually or in combination to predict good neurological outcomes at 6 months after CA., Methods: This was a retrospective analysis of the Korean Hypothermia Network Prospective Registry 1.0, which included adult out-of-hospital cardiac arrest (OHCA) patients (≥18 years). Good outcome predictors were defined as both pupillary light reflex (PLR) and corneal reflex (CR) at admission, Glasgow Coma Scale Motor score (GCS-M) >3 at admission, neuron-specific enolase (NSE) <17 µg/L at 24-72 h, a median nerve somatosensory evoked potential (SSEP) N20/P25 amplitude >4 µV, continuous background without discharges on electroencephalogram (EEG), and absence of anoxic injury on brain CT and diffusion-weighted imaging (DWI)., Results: A total of 1327 subjects were included in the final analysis, and their median age was 59 years; among them, 412 subjects had a good neurological outcome at 6 months. GCS-M >3 at admission had the highest specificity of 96.7% (95% CI 95.3-97.8), and normal brain DWI had the highest sensitivity of 96.3% (95% CI 92.9-98.4). When the two predictors were combined, the sensitivities tended to decrease (ranging from 2.7-81.1%), and the specificities tended to increase, ranging from81.3-100%. Through the explorative variation of the 2021 European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) prognostication strategy algorithms, good outcomes were predicted, with a specificity of 83.2% and a sensitivity of 83.5% in patients by the algorithm., Conclusions: Clinical examination, biomarker, electrophysiology, and brain imaging predicted good outcomes at 6 months after CA. When the two predictors were combined, the specificity further improved. With the 2021 ERC/ESICM guidelines, the number of indeterminate patients and the uncertainty of prognostication can be reduced by using a good outcome prediction algorithm., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The occurrence of a critical event during a urinary tract infection (UTI) can have a significant impact on mortality. This study aimed to investigate the association between the skeletal muscle index (SMI) and critical events in patients with a UTI. From April 2019 to March 2022, a total of 478 patients who met the diagnostic criteria of a UTI and underwent an abdominal CT were included in this study. Multivariate binary logistic regression analysis was used to assess independent predictors of critical events. The primary outcome was any critical event, defined as the initiation of dialysis, invasive ventilation, initiation of vasoactive medications, cardiac arrest, or death. The UTI patients were divided into two groups: those with a low SMI (n = 93) and those with a high SMI (n = 385). In multivariate analysis, a low SMI, diabetes mellitus, altered mentality, lactate levels, and creatinine levels were identified as significant predictors of critical events. A low SMI is an independent factor associated with the occurrence of critical events in UTI patients during hospitalization. Patients with a low SMI, indicating muscle wasting, may have less resilience to infections and a higher risk of experiencing severe complications. Considering the SMI along with other clinical factors can help health care providers assess and manage UTI patients.

Soybean-derived peptides exert several beneficial effects in various experimental models. However, only a few studies have focused on the radical scavenging and anti-wrinkle effects of soymilk-derived peptides produced via different processes, such as fermentation, enzymatic treatment, and ultrafiltration. Therefore, in this study, we investigated the radical scavenging and antiwrinkle effects of soymilk fractions produced using these processes. We found that 50SFMKUF5, a 5 kDa ultrafiltration fraction fermented with Lacticaseibacillus paracasei MK1 after flavourzyme treatment, exhibited the highest radical scavenging activity using the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay as well as potent anti-wrinkle effects assessed by type 1 procollagen production and tumor necrosis factor-α production in ultraviolet B (UVB)-treated human dermal fibroblasts and HaCaT keratinocytes. To identify potential bioactive peptides, candidate peptides were synthesized, and their anti-wrinkle effects were assessed. APEFLKEAFGVN (APE), palmitoyl-APE, and QIVTVEGGLSVISPK peptides were synthesized and used to treat UVB-irradiated fibroblasts, HaCaT keratinocytes, and α-melanocyte-stimulating hormone-induced B16F1 melanoma cells. Among these peptides, Pal-APE exerted the strongest effect. Our results highlight the potential of soymilk peptides as anti-aging substances.

Lactobacillus johnsonii 7409N31 was isolated from the feces of a healthy 11-day-old Hanwoo calf from a farm in Geochang-gun, Gyeongsangnam-do, Korea. The genome of the strain was completely sequenced using the PacBio RSII sequencing system, and it was confirmed that it was composed of one circular chromosome. The size of the entire genome was 2,198,442 bp, and it had 35.01 mol% guanine + cytosine (G + C) content and 2,222 protein-coding sequences, 24 rRNA, 3 ncRNA, and 112 tRNA genes. Strain 7409N31 possessed genes encoding enzymes involved in the hydrolysis of both fibrous and non-fibrous carbohydrates. These data provide a comprehensive theoretical understanding for developing industrial probiotic feed additives that improve nutrient digestibility., Competing Interests: No potential conflict of interest relevant to this article was reported., (© Copyright 2023 Korean Society of Animal Science and Technology.)

As an initial study to elucidate the molecular mechanism of how probiotics modulate macrophage activity, we monitored mRNA expression patterns in peritoneal macrophages (PMs) treated with two different strains of probiotics. After treatment with either Weissella cibaria WIKIM28 or Latilactobacillus sakei WIKIM50, total RNAs from PMs were isolated and subjected into gene chip analyses. As controls, mRNAs from vehicle (phosphate-buffered saline, PBS)-treated PMs were also subjected to gene chip analysis. Compared to vehicle (PBS)-treated PMs, WIKIM28-treated and WIKIM50-treated PMs exhibited a total of 889 and 432 differentially expressed genes with expression differences of at least 4 folds, respectively. Compared to WIKIM28-treated PMs, WIKIM50-treated PMs showed 25 up-regulated genes and 21 down-regulated genes with expression differences of more than 2 folds. Interestingly, mRNA transcripts of M2 macrophage polarization marker such as anxa1 , mafb , and sepp1 were increased in WIKIM50-treated PMs comparing to those in WIKIM28-treated PMs. Reversely, mRNA transcripts of M1 macrophage polarization marker such as hdac9 , ptgs2 , and socs3 were decreased in WIKIM50-treated PMs comparing to those in WIKIM28-treated PMs. In agreement with these observations, mRNA expression levels of tumor necrosis factor-α and interleukin-1α were significantly reduced in WIKIM50-treated macrophages compared to those in WIKIM28-treated macrophages. These results may indicate that probiotics can be classified as two different types depending on their ability to convert macrophages into M1 or M2 polarization., Competing Interests: The authors declare no potential conflicts of interest., (© Korean Society for Food Science of Animal Resources.)

Background: Severe sepsis and septic shock are the leading cause of in-hospital death. As sepsis progresses, expression and activity of endogenous mediators of inflammation change. Early detection of biomarkers can play a role in sepsis screening and in improvement of patient outcomes. Recent studies suggest that increase in monocyte volume may be helpful in early detection of sepsis. Therefore, we evaluated the utility of monocyte distribution width (MDW) for the early assessment of sepsis compared with the blood culture and other inflammatory biomarkers., Methods: Medical records of 1,404 patients (aged ≥19 years) who were admitted to the emergency department owing to clinically suspected infectious disease and requested blood cultures from Oct 2019 to Jan 2021 were reviewed. The patients were grouped based on Sepsis-3 criteria. They had undergone other laboratory tests to evaluate their clinical status. MDW was analyzed using DxH900 hematology analyzer (Beckman Coulter, Brea, California, USA). To determine the diagnostic performance of MDW, C-reactive protein (CRP), and procalcitonin (PCT) for sepsis, the area under the curve (AUC) of receiver operating characteristics curves and their sensitivity and specificity were measured., Results: Among 1,404 patients, 520 patients were designated the sepsis group based on Sepsis-3 criteria. In the sepsis group, MDW value was 24.1 (median, IQR 21.6-28.1); AUC values for MDW, CRP, and PCT were 0.67 (95% CI, 0.64-0.69), 0.66 (95% CI, 0.63-0.68), and 0.75 (95% CI, 0.72-0.77), respectively. For diagnosis of the sepsis, the cut-off value of MDW was 21.7 (sensitivity 74% and specificity 54%). Measured values of MDW were higher for the blood culture positive group than that of the blood culture contamination group (P<0.001, 95% CI, -5.9 to -3.0) or blood culture negative group (P<0.001, 95% CI = -5.8 to -4.2)., Conclusions: MDW is a new hematological parameter that is simultaneously calculated during complete blood cell counting by Beckman Coulter hematology analyzer. MDW is expected to serve as a useful indicator for early screening of sepsis in conjunction with CRP and PCT. MDW is especially useful for sepsis assessment in patients with a suspected infection. MDW can also assist in discriminating false positive blood cultures., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Jo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Introduction: We investigated the clinical characteristics, outcomes and factors related to the serious adverse events (AEs) of patients visiting the emergency department (ED) with various AEs after ChAdOx1 and mRNA COVID-19 vaccination., Methods: Patients with AEs who visited the ED between March 2021 and September 2021 were selected from three EDs. The clinical data of these patients were collected by retrospectively reviewing medical records. Serious adverse events (AEs) were defined as any adverse medical events that led to hospital admission., Results: A total of 3572 patients visited the ED with AEs; 69.6% were administered mRNA vaccines, and the median (IQR) age was 48 (31-63) years. Regarding chief complaints, chest pain/discomfort (43.7%) was most common in the mRNA vaccines group, while fever (15.8%) was more commonly presented in the ChAdOx1 group. Most patients (93.9%) were discharged from the ED. In multivariate analysis, age ≥70 years, days from vaccination to ED visit ≥8 days, fever and dyspnea as chief complaints were higher independent risk factors for serious AEs (OR 27.94, OR 2.55, OR 1.95 and OR 2.18: p < 0.001, p < 0.001, p = 0.003 and p = 0.003, respectively)., Conclusion: Most patients who visited the ED with AEs after vaccination were discharged from the ED regardless of the type of vaccine. Emergency physicians need to differentiate serious AEs and consider factors that may require admission to the ED., Competing Interests: Declaration of competing interest The authors have no potential conflicts of interest to disclose., (Copyright © 2022 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Background: Sepsis is a series of organ failures caused by dysregulated responses to infection. Risk factors for sepsis are multiple comorbidities, a poor nutrition status, and limited mobility. The primary purpose of the study was to determine whether ambulation ability with albumin and C-reactive protein are predictive of 28-day mortality of elderly patients with sepsis., Methods: This was a retrospective observational study using a multicentre-based registry of elderly patients between November 2016 and February 2017. The inclusion criteria were a patient ≥65 years and a diagnosis of sepsis and exclusion criteria were a patient with covariates of ambulation ability such as central nervous system diseases, or malignancy. The area under the receiver operating characteristic curve of prediction models were calculated and compared. The survival rates according to the ambulation ability were estimated and compared by the log-rank test., Results: 2291 patients ≥65 years visited with infectious diseases. 496 subjects with central nervous system diseases, 710 subjects with malignancy and 817 subjects with a Sequential Organ Failure Assessment score ≤ 1 were excluded. Ultimately, 278 subjects were included in the primary analysis. 133 (47.8%) subjects were male and the median age was 78 years. 228 (82%) subjects could ambulate independently before morbidity and 28 (10.1%) subjects expired in 28 days. In the inability to ambulate and C-reactive protein to albumin ratio model, the area under the curve predicting 28-day mortality was 0.761 with no significant difference from the Sequential Organ Failure Assessment score (0.859, p = 0.097) and the estimated survival rate on 28th day according to the ability to ambulate showed a significant difference (hazard ratio = 1.212, p < 0.001)., Conclusion: The premorbid ambulation ability with albumin and C-reactive protein can be combined to predict 28-day mortality in elderly patients with sepsis., (© 2022. The Author(s).)

A high-fat diet (HFD) induces low-grade, chronic inflammation throughout the body including the hypothalamus, a key brain region involved in the control of satiety and energy expenditure in central nervous system (CNS). Kimchi is a traditional fermented Korean food, which is recognized as a healthy food. In this study, we evaluated its ability to suppress the obesity-induced inflammation in mice fed an HFD. Male C57BL/6 mice were fed an HFD or HFD with kimchi (pH 5.2 ∼ 5.8). Oral administration of kimchi significantly reduced the body weight, fat mass gain, and levels of pro-inflammatory cytokines in serum. Furthermore, kimchi diminished the HFD-induced activation of astrocyte and microglial cells (reactive gliosis, a hallmark of CNS injury and inflammation) in hypothalamus region. IgG accumulation assay showed that kimchi ingestion suppressed HFD-induced breakage of the blood brain barrier (BBB) via upregulating the expression of tight junction molecules in cerebrovascular endothelial cells. In addition, kimchi modulated gut microbiome profiles, which showed an increase in the abundance of Akkermansia muciniphila. Moreover, kimchi enhanced acetate level and BBB integrity in A. muciniphila-colonized gnotobiotic mice. These results suggest that kimchi may exert beneficial effects to prevent and ameliorate obesity and associated neuroinflammation by changing gut microbiota composition and short-chain fatty acids production., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Among comatose survivors of out-of-hospital cardiac arrest (OHCA), targeted temperature management (TTM) has improved neurological outcomes. However, although the target temperature shifted from 33°C to 33°C~36°C, the optimal target temperature is still unclear. The goal of this study was to evaluate neurological outcomes at 6 months at target temperatures of 33°C and 36°C., Materials and Methods: We analyzed OHCA survivors who underwent TTM and were recorded in the Korean Hypothermia Network, a prospective multicenter registry, from October 2015 to December 2018. The primary outcome was good neurological outcome at six months, defined as a cerebral performance category of 1-2, and the secondary outcome was survival at 6 months., Results: A total of 1339 patients were treated with TTM in twenty-two emergency departments. Of those, 1054 were treated at 33°C, and 285 were treated at 36°C. There was no significant difference in good neurological outcomes at 6 months (30.6% vs. 31.2%, p = 0.850, adjusted OR 0.97, 95% CI = 0.73-1.29]) and survival at six months (41.4% vs. 38.7%, p = 0.401, adjusted HR 1.08, 95% CI = 0.91-1.28]) between TTM 33°C and TTM 36°C. After propensity score matching, good neurological outcomes at 6 months (OR 0.93, 95% CI = 0.74-1.18) and survival at 6 months (HR 1.05, 95% CI = 0.92-1.21) were still not associated with TTM 33°C and TTM 36°C., Conclusion: In this study, patients treated with a target temperature of 33°C had similar good neurological outcomes and survival at six months compared with those treated with a target temperature of 36°C., Competing Interests: The authors have declared that no competing interests exist.

Allergic rhinitis (AR) is a type I hypersensitivity mediated by dominant T helper 2 (Th2) response over the Th1 response after re-exposure to a specific allergen. Currently, socio-economic cost evoked by AR is quickly increasing since the prevalence of AR is gradually increasing in all ages worldwide. Several probiotic Lactobacillus strains have been described with potential immunomodulatory effects against type I hypersensitivity such as AR. Thus, the aim of the present work was to characterize basic probiotic property and immunomodulatory role of newly isolated Lactobacillus strains from Kimchi, a traditional fermented Korean food, in AR. Among the identified strains, Lactiplantibacillus plantarum NR16 revealed to be a powerful Th1 inducer since immune cells co-cultured with NR16 produced the highest quantity of interferon-γ (IFN-γ) and interleukin-12 (IL-12) but secreted a low amount of IL-4 in vitro. Therefore, NR16 was selected for the following assays conducted with mice with birch pollen-induced AR. Oral administration of NR16 reduced airway hyperresponsiveness and leukocyte infiltration in lesions of mice. In conclusion, oral administration of NR16 may mitigate symptoms of AR by inducing Th1 immune response, which might rebalance Th2/Th1 ratio by decreasing Th2 cytokine production in specific lesions of mucosa., (© 2022 The Society for Applied Microbiology.)

Purpose: To assess the performance of the post-cardiac arrest (CA) prognostication strategy algorithm recommended by the European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) in 2020., Methods: This was a retrospective analysis of the Korean Hypothermia Network Prospective Registry 1.0. Unconscious patients without confounders at day 4 (72-96 h) after return of spontaneous circulation (ROSC) were included. The association between the prognostic factors included in the prognostication strategy algorithm, except status myoclonus and the neurological outcome, was investigated, and finally, the prognostic performance of the prognostication strategy algorithm was evaluated. Poor outcome was defined as cerebral performance categories 3-5 at 6 months after ROSC., Results: A total of 660 patients were included in the final analysis. Of those, 108 (16.4%) patients had a good neurological outcome at 6 months after CA. The 2020 ERC/ESICM prognostication strategy algorithm identified patients with poor neurological outcome with 60.2% sensitivity (95% CI 55.9-64.4) and 100% specificity (95% CI 93.9-100) among patients who were unconscious or had a GCS&#95;M score ≤ 3 and with 58.2% sensitivity (95% CI 53.9-62.3) and 100% specificity (95% CI 96.6-100) among unconscious patients. When two prognostic factors were combined, any combination of prognostic factors had a false positive rate (FPR) of 0 (95% CI 0-5.6 for combination of no PR/CR and poor CT, 0-30.8 for combination of No SSEP N20 and NSE 60)., Conclusion: The 2020 ERC/ESICM prognostication strategy algorithm predicted poor outcome without an FPR and with sensitivities of 58.2-60.2%. Any combinations of two predictors recommended by ERC/ESICM showed 0% of FPR., (© 2022. The Author(s).)

We evaluated the performance of cardiac arrest-specific prognostication scores developed for outcome prediction in the early hours after out-of-hospital cardiac arrest (OHCA) in predicting long-term outcomes using independent data. The following scores were calculated for 1,163 OHCA patients who were treated with targeted temperature management (TTM) at 21 hospitals in South Korea: OHCA, cardiac arrest hospital prognosis (CAHP), C-GRApH (named on the basis of its variables), TTM risk, 5-R, NULL-PLEASE (named on the basis of its variables), Serbian quality of life long-term (SR-QOLl), cardiac arrest survival, revised post-cardiac arrest syndrome for therapeutic hypothermia (rCAST), Polish hypothermia registry (PHR) risk, and PROgnostication using LOGistic regression model for Unselected adult cardiac arrest patients in the Early stages (PROLOGUE) scores and prediction score by Aschauer et al. Their accuracies in predicting poor outcome at 6 months after OHCA were determined using the area under the receiver operating characteristic curve (AUC) and calibration belt. In the complete-case analyses, the PROLOGUE score showed the highest AUC (0.923; 95% confidence interval [CI], 0.904-0.941), whereas the SR-QOLl score had the lowest AUC (0.749; 95% CI, 0.711-0.786). The discrimination performances were similar in the analyses after multiple imputation. The PROLOGUE, TTM risk, CAHP, NULL-PLEASE, 5-R, and cardiac arrest survival scores were well calibrated. The rCAST and PHR risk scores showed acceptable overall calibration, although they showed miscalibration under the 80% CI level at extreme prediction values. The OHCA score, C-GRApH score, prediction score by Aschauer et al., and SR-QOLl score showed significant miscalibration in both complete-case (P = 0.026, 0.013, 0.005, and < 0.001, respectively) and multiple-imputation analyses (P = 0.007, 0.018, < 0.001, and < 0.001, respectively). In conclusion, the discrimination performances of the prognostication scores were all acceptable, but some showed significant miscalibration., Competing Interests: The authors have declared that no competing interests exist.

Early prognostication in cardiac arrest survivors is challenging for physicians. Unlike other prognostic modalities, biomarkers are easily accessible and provide an objective assessment method. We hypothesized that in cardiac arrest patients with targeted temperature management (TTM), early circulating microRNA (miRNA) levels are associated with the 6-month neurological outcome. In the discovery phase, we identified candidate miRNAs associated with cardiac arrest patients who underwent TTM by comparing circulating expression levels in patients and healthy controls. Next, using a larger cohort, we validated the prognostic values of the identified early miRNAs by measuring the serum levels of miRNAs, neuron-specific enolase (NSE), and S100 calcium-binding protein B (S100B) 6 h after cardiac arrest. The validation cohort consisted of 54 patients with TTM. The areas under the curve (AUCs) for poor outcome were 0.85 (95% CI (confidence interval), 0.72-0.93), 0.82 (95% CI, 0.70-0.91), 0.78 (95% CI, 0.64-0.88), and 0.77 (95% CI, 0.63-0.87) for miR-6511b-5p, -125b-1-3p, -122-5p, and -124-3p, respectively. When the cut-off was based on miRNA levels predicting poor outcome with 100% specificity, sensitivities were 67.7% (95% CI, 49.5-82.6), 50.0% (95% CI, 32.4-67.7), 35.3% (95% CI, 19.7-53.5), and 26.5% (95% CI, 12.9-44.4) for the above miRNAs, respectively. The models combining early miRNAs with protein biomarkers demonstrated superior prognostic performance to those of protein biomarkers.

The gray-to-white matter ratio (GWR) has been used to identify brain damage in comatose patients after cardiac arrest. However, Hounsfield units (HUs), the measurement of brain density on computed tomography (CT) images, may vary depending on the machine type or parameter. Therefore, differences in CT scanners may affect the GWR in post-cardiac arrest patients. We performed a retrospective study on comatose post-cardiac arrest patients who visited the hospital from 2007 to 2017. Two CT, Lightspeed and SOMATOM, scanners were used. Two observers independently measured the HUs of the caudate nucleus, putamen, posterior internal capsule, and corpus callosum using regions of interest. We compared the GWR calculated from the HUs measured at different CT scanners. The analysis of different scanners showed statistically significant differences in the measured HUs and GWR. The HUs and GWR of Lightspeed were measured lower than SOMATOM. The difference between the two CT scanners was also evident in groups divided by neurological prognosis. The area under the curve of the receiver operating characteristic curve to predict poor outcomes of Lightspeed was 0.798, and the cut-off value for 100% specificity was 1.172. The SOMATOM was 0.855, and the cut-off value was 1.269. The difference in scanners affects measurements and performance characteristics of the GWR in post-cardiac arrest patients. Therefore, when applying the results of the GWR study to clinical practice, reference values for each device should be presented, and an integrated plan should be prepared., Competing Interests: The authors have declared that no competing interests exist.

Purpose: We analysed the prognostic value of somatosensory, brainstem auditory and visual evoked potentials (SSEPs, BAEPs and VEPs, respectively) for outcome prediction in cardiac arrest patients with targeted temperature management (TTM) and assessed whether BAEP and VEP measurements conferred added value to SSEP measurements., Methods: Cases with SSEPs and VEPs or BAEPs were reviewed in a TTM registry. We focused on whether the following responses were clearly discernible: N20 for SSEPs, V for BAEPs, and P100 for VEPs. Each type of evoked potential was classified as absent, present or indeterminable. Neurological outcomes after 6 months were dichotomized as good (Cerebral Performance Category [CPC] 1-2) or poor (CPC 3-5)., Results: From 185 patients, 185 SSEPs, 172 BAEPs and 178 VEPs were included. None of the patients with a good outcome had absent SSEP, BAEP or VEP responses. Absent SSEP, BAEP and VEP responses yielded sensitivities of 42.3% (95% confidence interval [CI], 33.7-51.3%), 9.4% (95% CI, 4.6-16.7%) and 54.4% (95% CI, 46.0-62.5%) for poor outcomes, respectively. For the overall cohort, the addition of VEP measurements improved the sensitivities of single SSEP measurements (65.8% [95% CI, 57.7-73.3%] versus 36.2% [95% CI, 28.6-44.4%] and multimodal prognostication using SSEPs, brainstem reflex and brain computed tomography (75.7% [95% CI, 68.0-82.3%] versus 60.5% [95% CI, 52.3-68.4%])., Conclusions: The prognostic value of VEPs was comparable to that of SSEPs, but the use of BAEPs was limited due to their low sensitivity. Additional VEP measurements can reduce prognostic uncertainty., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Aim of the Study: We investigated whether controlled normothermia (CN) after the rewarming phase of targeted temperature management (TTM) is associated with preventing post-rewarming fever and outcomes 6 months after out-of-hospital cardiac arrest (OHCA)., Methods: This was an analysis of a prospective registry comprising OHCA patients treated with TTM at 22 academic hospitals between October 2015 and December 2018. We calculated the incremental area under the curve (iAUC) for body temperature greater than or equal to 37.5 °C for each patient during the first 24 h after the end of rewarming. The relationships among CN and iAUC, 6-month survival and good neurological outcome were analysed. To minimize differences in the baseline characteristics of the patients, we used propensity score-matched analysis., Results: In total, 1144 patients were enrolled. After propensity score matching, 646 patients (comprising 323 pairs) were obtained. In the unmatched cohort, post-rewarming CN was significantly associated with a lower iAUC (0.34 [1.38] vs. 1.19 [2.27]; p < 0.001) but not 6-month survival (adjusted odds ratio (OR): 1.121; 95% confidence interval (CI): 0.836-1.504; p = 0.446) and good neurological outcome (adjusted OR: 1.030; 95% CI: 0.734-1.446; p = 0.863). The results were similar in the propensity score-matched cohort (0.38 [1.56] vs. 1.03 [2.21], p < 0.001, OR: 1.347, 95% CI: 0.989-1.835, p = 0.059 and OR: 1.280, 95% CI 0.925-1.772, p = 0.137, respectively)., Conclusion: Post-rewarming CN prevents high fever in the normothermia phase of TTM. However, our data suggest the lack of association between CN and the patient's 6-month survival and good neurological outcome., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Grammatical Error Correction (GEC) is the task of detecting and correcting various grammatical errors in texts. Many previous approaches to the GEC have used various mechanisms including rules, statistics, and their combinations. Recently, the performance of the GEC in English has been drastically enhanced due to the vigorous applications of deep neural networks and pretrained language models. Following the promising results of the English GEC tasks, we apply the Transformer with Copying Mechanism into the Korean GEC task by introducing novel and effective noising methods for constructing Korean GEC datasets. Our comparative experiments showed that the proposed system outperforms two commercial grammar check and other NMT-based models.

Limit order books (LOBs) have been widely adopted as a trading mechanism in global securities markets, and the degree of LOB transparency is one of the most studied topics in market design. In the past, this issue was mainly researched through the comparison of LOB transparency in a market before and after a policy change, although such instances were rare and occurred decades ago. This article analyzes the importance of broker identities (IDs) in the LOB with respect to price movement predictability by proposing a different approach. By analyzing raw LOB data, an enormous dataset of selected Hong Kong stocks is divided into two parts, namely the prices and order volumes (anonymous LOBs), and a list of broker IDs in the bid and ask queues. A deep learning model is then employed to predict the mid-price movement after 20 ticks. Our result indicates that the best F1 scores of the anonymous LOB and broker ID models are fairly high, ranging from 57.63% to 68.70% and from 53.70% to 59.39%, respectively. When comparing the performance of both datasets, surprisingly, the overall F1 prediction performance based solely on the broker ID dataset can reach, on average, 85.13% that of the anonymous LOB dataset. The contributions of this study are twofold. First, a machine learning-based tool for finance researchers is proposed to quantitatively measure the price predictability of LOB features, and the results of the impact of LOB transparency on traders' profitability are novel as this study is empirical. Second, the empirical result strongly suggests that the broker ID queues in the LOB consist of significant information content for price prediction, and thus, the study provides insights for regulators to determine the appropriate degree of LOB transparency to guarantee a fair market for all investors.

(1) Background: Follow-up management of workers' general health examination (WGHE) is important, but it is not currently well done. Chatbot, a type of digital healthcare tool, is used in various medical fields but has never been developed for follow-up management of WGHE in Korea. (2) Methods: The database containing results and explanations related to WGHE was constructed. Then, the channel, which connects users with the database was created. A user survey regarding effectiveness was administered to 23 healthcare providers. Additionally, interviews on applicability for occupational health services were conducted with six nurses in the agency of occupational health management. (3) Results: Chatbot was implemented on a small scale on the Amazon cloud service (AWS) EC2 using KaKaoTalk and Web Chat as user channels. Regarding the effectiveness, 21 (91.30%) rated the need for chatbots as very high; however, 11 (47.83%) rated the usability as not high. Of the 23 participants, 14 (60.87%) expressed overall satisfaction. Nurses appreciated the chatbot program as a method for resolving accessibility and as an aid for explaining examination results and follow-up management. (4) Conclusions: The effectiveness of WGHE and the applicability in the occupational health service of the chatbot program for follow-up management can be confirmed.

Objective: High-quality intensive care, including targeted temperature management (TTM) for patients with postcardiac arrest syndrome, is a key element for improving outcomes after out-of-hospital cardiac arrest (OHCA). We aimed to assess the status of postcardiac arrest syndrome care, including TTM and 6-month survival with neurologically favorable outcomes, after adult OHCA patients were treated with TTM, using data from the Korean Hypothermia Network prospective registry., Methods: We used the Korean Hypothermia Network prospective registry, a web-based multicenter registry that includes data from 22 participating hospitals throughout the Republic of Korea. Adult comatose OHCA survivors treated with TTM between October 2015 and December 2018 were included. The primary outcome was neurological outcome at 6 months., Results: Of the 1,354 registered OHCA survivors treated with TTM, 550 (40.6%) survived 6 months, and 413 (30.5%) had good neurological outcomes. We identified 839 (62.0%) patients with preClinsumed cardiac etiology. A total of 937 (69.2%) collapses were witnessed, shockable rhythms were demonstrated in 482 (35.6%) patients, and 421 (31.1%) patients arrived at the emergency department with prehospital return of spontaneous circulation. The most common target temperature was 33°C, and the most common target duration was 24 hours., Conclusion: The survival and good neurologic outcome rates of this prospective registry show great improvements compared with those of an earlier registry. While the optimal target temperature and duration are still unknown, the most common target temperature was 33°C, and the most common target duration was 24 hours.

Background: Prognostication after cardiac arrest (CA) needs a multimodal approach, but the optimal method is not known. We tested the hypothesis that the combination of neuron-specific enolase (NSE) and neuroimaging could improve outcome prediction after CA treated with targeted temperature management (TTM)., Methods: A retrospective observational cohort study was performed on patients who underwent at least one NSE measurement between 48 and 72 hr; received both a brain computed tomography (CT) scan within 24 hr and diffusion-weighted magnetic resonance imaging (DW-MRI) within 7 days after return of spontaneous circulation (ROSC); and were treated with TTM after out-of-hospital CA between 2009 and 2017 at the Seoul St. Mary's Hospital in Korea. The primary outcome was a poor neurological outcome at 6 months after CA, defined as a cerebral performance category of 3-5., Results: A total of 109 subjects underwent all three tests and were ultimately included in this study. Thirty-four subjects (31.2%) experienced good neurological outcomes at 6 months after CA. The gray matter to white matter attenuation ratio (GWR) was weakly correlated with the mean apparent diffusion coefficient (ADC), PV400 and NSE (Spearman's rho: 0.359, -0.362 and -0.263, respectively). NSE was strongly correlated with the mean ADC and PV400 (Spearman's rho: -0.623 and 0.666, respectively). Serum NSE had the highest predictive value among the single parameters (area under the curve (AUC) 0.912, sensitivity 70.7% for maintaining 100% specificity). The combination of a DWI parameter (mean ADC or PV400) and NSE had better prognostic performance than the combination of the CT parameter (GWR) and NSE. The addition of the GWR to a DWI parameter and NSE did not improve the prediction of neurological outcomes., Conclusion: The GWR (≤ 24 hr) is weakly correlated with the mean ADC (≤ 7 days) and NSE (highest between 48 and 72 hr). The combination of a DWI parameter and NSE has better prognostic performance than the combination of the GWR and NSE. The addition of the GWR to a DWI parameter and NSE does not improve the prediction of neurological outcomes after CA treatment with TTM., Competing Interests: The authors have declared that no competing interests exist.

Background: Community-based active contact and follow-up are known to be effective in reducing the risk of repeat suicide attempts among patients admitted to emergency departments after attempting suicide. However, the characteristics that define successful collaborations between emergency departments and community-based mental healthcare centers in this context are not well known., Methods: This study investigated patients visiting the emergency department after suicide attempts from May 2017 to April 2019. Patients were classified in either the successful collaboration group or the failed collaboration group depending on whether or not they were linked to a community-based follow-up intervention. Clinical features and socioeconomic status were considered as independent variables. Logistic regression analysis was performed to identify factors influencing the collaboration., Results: Of 674 patients, 153 (22.7%) were managed successfully via the targeted collaboration. Completion of hospital-based psychological counseling (adjusted odds ratio [aOR], 233.55; 95% confidence interval [CI], 14.99-3,637.67), supported out-of-pocket expenses (aOR, 11.17; 95% CI, 3.03-41.03), Korean Triage and Acuity Scale 1-3 (aOR, 4.31; 95% CI, 1.18-15.73), suicide attempt associated with mental disorder (aOR, 0.15; 95% CI, 0.04-0.52), and self-discharge against medical advice (aOR, 0.12; 95% CI, 0.02-0.70) were independent factors influencing the collaboration., Conclusion: Completion of hospital-based psychological counseling was the most highly influential factor determining the outcome of the collaboration between the emergency department and community-based mental healthcare center in the management of individuals who had attempted suicide. Completion of hospital-based psychological counseling is expected to help reduce the risk of repeat suicide attempts., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2020 The Korean Academy of Medical Sciences.)

We investigated the association between post-rewarming fever (PRF) and 6-month neurologic outcomes in cardiac arrest survivors. This was a multicenter study based on a registry of comatose adult (≥18 years) out-of-hospital cardiac arrest (OHCA) survivors who underwent targeted temperature management between October 2015 to December 2018. PRF was defined as peak temperature ≥ 38.0 °C within 72 h after completion of rewarming, and PRF timing was categorized as within 24, 24-48, and 48-72 h epochs. The primary outcome was neurologic outcomes at six months after cardiac arrest. Unfavorable neurologic outcome was defined as cerebral performance categories three to five. A total of 1031 patients were included, and 642 (62.3%) had unfavorable neurologic outcomes. PRF developed in 389 (37.7%) patients in 72 h after rewarming: within 24 h in 150 (38.6%), in 24-48 h in 155 (39.8%), and in 48-72 h in 84 (21.6%). PRF was associated with improved neurologic outcomes (odds ratio (OR), 0.633; 95% confidence interval (CI), 0.416-0.963). PRF within 24 h (OR, 0.355; 95% CI, 0.191-0.659), but not in 24-48 h or 48-72 h, was associated with unfavorable neurologic outcomes. Early PRF within 24 h after rewarming was associated with favorable neurologic outcomes.

Objectives: The aim of this study was to evaluate the prognostic performance of the peak amplitude of P25/30 cortical somatosensory evoked potentials in predicting nonawakening in targeted temperature management-treated cardiac arrest patients., Design: Prospective analysis., Setting: Four academic tertiary care hospitals., Patients: Eighty-seven cardiac arrest survivors after targeted temperature management., Interventions: Analysis of the amplitude of P25/30., Measurements and Main Results: In all participants, somatosensory evoked potentials were recorded after rewarming, and bilaterally absent pupillary and corneal reflexes were evaluated at 72 hours after the return of spontaneous circulation. We analyzed the amplitudes of the N20 and P25/30 peaks and the N20-P25/30 complex in cortical somatosensory evoked potentials. Upon hospital discharge, 87 patients were dichotomized into the awakening and nonawakening groups. The lowest amplitudes of N20, P25/30, and N20-P25/30 in the awakening patients were 0.17, 0.45, and 0.73 μV, respectively, and these thresholds showed a sensitivity of 70.5% (95% CI, 54.8-83.2%), 86.4% (95% CI, 72.7-94.8%), and 75.0% (95% CI, 59.7-86.8%), respectively, for nonawakening. The area under the curve of the P25/30 amplitude was significantly higher than that of the N20 amplitude (0.955 [95% CI, 0.912-0.998] vs 0.894 [95% CI, 0.819-0.969]; p = 0.036) and was comparable with that of the N20-P25/30 amplitude (0.931 [95% CI, 0.873-0.989]). Additionally, adding resuscitation variables or an absent brainstem reflex to the P25/30 amplitude showed a trend toward improving prognostic performance compared with the use of other somatosensory evoked potential amplitudes (area under the curve, 0.958; 95% CI, 0.917-0.999 and area under the curve, 0.974; 95% CI, 0.914-0.996, respectively)., Conclusions: Our results provide evidence that the absence of the P25/30 peak and a reduction in the P25/30 amplitude may be considered prognostic indicators in these patients.

Background: The purpose of this study was to assess the reliability and validity of the 3-item version of the Work Engagement Scale (WES-3), which is based on the Job Demands-Resources (JD-R) model and was used in the 5 th Korean Working Conditions Survey (KWCS)., Methods: This study used data from the 5th KWCS (n = 50,205), which was conducted in 2017 with a sample of the Korean working population. The survey gathered comprehensive information on working conditions to define workforce changes and the quality of work and life. The reliability and internal consistency of the WES-3 were assessed using the corrected item-total correlation and Cronbach's alpha coefficient. Confirmatory factor analysis (CFA) was used to test the construct validity of work engagement. The convergent validity was assessed using the correlation with the WHO-5 well-being index. Correlations between work engagement and JD-R factors were also calculated., Results: The Cronbach's alpha for work engagement was 0.776, indicating acceptable internal consistency. The model comprising 3 work engagement and 2 burnout items showed an excellent fit (χ 2 : 382.05, Tucker-Lewis index: 0.984, comparative fit index: 0.994, root mean square error of approximation: 0.043). The convergent validity was significant (correlation coefficient: 0.42). Correlations with burnout and job demands were negligible, whereas correlations with job resources and job satisfaction were weakly positive., Conclusions: The results of our study confirm that the WES-3 has acceptable reliability and validity., Competing Interests: Competing interests: The authors declare that they have no competing interest., (Copyright © 2020 Korean Society of Occupational & Environmental Medicine.)

Background: The reliability of somatosensory evoked potential (SSEP) to predict a poor outcome of cardiac arrest patients after targeted temperature management (TTM) has been questioned due to self-fulfilling prophecy., Methods: This was a multicentre, prospective, registry-based study. Data were collected from the Korean Hypothermia Network (KORHN)-pro registry between November 2015 and December 2018. We excluded cases with possible bias (inappropriate SSEP recordings and patients who decided on the withdrawal of life-sustaining therapy [WLST]) and calculated the sensitivities and false positive rates (FPRs) for an absent N20 and an absent brainstem reflex. A poor outcome was defined as a cerebral performance category score of 3-5 after 6 months., Results: A total of 262 patients were analysed: 83 in the good outcome group and 179 in the poor outcome group. A bilaterally absent N20 was found in 127 patients and predicted a poor outcome with a sensitivity of 71.0% (95% confidence interval [CI], 63.7-77.5) and an FPR of 0.0% (95% CI, 0.0-4.3). Among the patients with absent brainstem reflexes (n = 103), 3 had a good outcome, with an FPR of 4.3% (95% CI, 0.9-12.2). The absence of one or both N20 and brainstem reflex had a sensitivity of 84.2% (95% CI, 77.4-89.6) and an FPR of 4.3% (95% CI, 0.9-12.2)., Conclusions: Our results provide further evidence that SSEP exactly predicts poor neurological outcome in these patients and suggest that caution be taken when the brainstem reflex is used as a single test to make decisions regarding WLST., (Copyright © 2020. Published by Elsevier B.V.)

Objective: The aim of this study in out-of-hospital cardiac arrest (OHCA) patients treated with targeted temperature management (TTM) was to evaluate the prognostic value of OHCA, C-GRApH, and CAHP scores with initial neurologic examinations for predicting neurologic outcomes., Methods: This retrospective study included OHCA patients treated with TTM from 2009 to 2017. We calculated three cardiac arrest (CA)-specific risk scores (OHCA, C-GRApH, and CAHP) at the time of admission. The initial neurologic examination included an evaluation of the Full Outline of UnResponsiveness brainstem reflexes (FOUR&#95;B) and Glasgow Coma Scale motor (GCS&#95;M) scores. The primary outcome was the neurologic outcome at hospital discharge., Results: Of 311 subjects, 99 (31.8%) had a good neurologic outcome at hospital discharge. The OHCA score had an area under the receiver operating characteristic curve (AUROC) of 0.844 (95% confidence interval (CI): 0.798-0.884), the C-GRApH score had an AUROC of 0.779 (95% CI: 0.728-0.824), and the CAHP score had an AUROC of 0.872 (95% CI: 0.830-0.907). The addition of the FOUR&#95;B or GCS&#95;M score to the OHCA score improved the prediction of poor neurologic outcome (with FOUR&#95;B: AUROC = 0.899, p = 0.001; with GCS&#95;M: AUROC = 0.880, p = 0.004). The results were similar with the C-GRApH and CAHP scores in predicting poor neurologic outcome., Conclusions: This study confirms the good prognostic performance of CA-specific scores to predict neurologic outcomes in OHCA patients treated with TTM. By adding new variables associated with the initial neurologic examinations, the prognoses of neurologic outcomes improved compared to the existing scoring models., Competing Interests: The authors have declared that no competing interests exist.

Background: The effect of renal replacement therapy (RRT) on the outcomes of severe acute kidney injury (AKI) after out-of-hospital cardiac arrest (OHCA) is uncertain. This study aimed to evaluate the association of RRT with 6-month mortality in patients with severe AKI treated with targeted temperature management (TTM) after OHCA., Methods: This was a retrospective analysis of a prospectively collected multicentre observational cohort study that included adult OHCA patients treated with TTM across 22 hospitals in South Korea between October 2015 and December 2018. AKI was diagnosed using the Kidney Disease: Improving Global Outcomes criteria. The primary outcome was 6-month mortality and the secondary outcome was cerebral performance category (CPC) at 6 months. Multivariate Cox regression analysis was performed to define the role of RRT in stage 3 AKI., Results: Among 10,426 patients with OHCA, 1373 were treated with TTM. After excluding those who died within 48 h of return of spontaneous circulation (ROSC) and those with pre-arrest chronic kidney disease, our study cohort comprised 1063 patients. AKI developed in 590 (55.5%) patients and 223 (21.0%) had stage 3 AKI. Among them, 115 (51.6%) were treated with RRT. The most common treatment modality among RRT patients was continuous renal replacement therapy (111 [96.5%]), followed by intermittent haemodialysis (4 [3.5%]). The distributions of CPC (1-5) at 6 months for the non-RRT vs. the RRT group were 3/108 (2.8%) vs. 12/115 (10.4%) for CPC 1, 0/108 (0.0%) vs. 1/115 (0.9%) for CPC 2, 1/108 (0.9%) vs. 3/115 (2.6%) for CPC 3, 6/108 (5.6%) vs. 6/115 (5.2%) for CPC 4, and 98/108 (90.7%) vs. 93/115 (80.9%) for CPC 5, respectively (P = 0.01). The RRT group had significantly lower 6-month mortality than the non-RRT group (93/115 [81%] vs. 98/108 [91%], P = 0.04). Multivariate Cox regression analyses showed that RRT was independently associated with a lower risk of death in patients with stage 3 AKI (hazard ratio, 0.569 [95% confidence interval, 0.377-0.857, P = 0.01])., Conclusion: Dialysis interventions were independently associated with a lower risk of death in patients with stage 3 AKI treated with TTM after OHCA.

Our goal is to fabricate flexible magnetic polymer composites as antenna substrates for very high frequency (VHF)/low ultra high frequency (UHF) antennas for unmanned aerial vehicles (UAVs) and medical devices. Magnetodielectric materials, which have permeability ( μ ) similar to permittivity ( ε ), have attracted great attention, because they facilitate miniaturization of microwave devices while keeping or enhancing electromagnetic characteristics. Mechanically millled Ba 1.5 Sr 1.5 Co 2 Fe 24 O 41 (Ba 1.5 Sr 1.5 Z) hexaferrite particles were used to increase permeability in the interesting frequency band. The microwave properties of Ba 1.5 Sr 1.5 Z composites were predicted and measured. Hansen's zero-order analysis of antenna bandwidth and electromagnetic field simulation showed that the hexaferrite-based flexible composite could enhance a bandwidth and achieve the miniaturization of antennas as well. The magnetic antenna substrates can be a good solution to integrate antennas into the UAVs whose dimensions are comparable to or larger than communication wavelength.

Introduction: It is well known that hypoalbuminemia is associated with adverse outcomes in various critical illnesses. However, there are few studies specifically measuring the association between albumin level and neurologic outcomes after CA treated with TTM. The aim of this study was to assess whether serum albumin concentration on admission had prognostic value for OHCA patients treated with TTM., Methods: We included adult patients aged ≥18 years with nontraumatic OHCA treated with TTM whose serum albumin concentration was available and who were admitted from 2009 to 2016. Serum albumin was measured within 1 h after ROSC, and hypoalbuminemia was defined as admission serum albumin <3.5 g/dl. A good neurologic outcome was defined as a cerebral performance category score of 1 or 2 at 6 months., Results: A total of 255 patients were eligible for analysis, of whom 106 (41.6%) survived to 6 months; 84 (32.9%) of these patients achieved favorable neurologic outcomes. The mean albumin values were significantly lower in patients with poor neurologic outcomes than the values in those with good neurologic outcomes (3.3 ± 0.6 vs. 3.9 ± 0.4, respectively, p < 0.001). After adjusting the crude model, patients in the hypoalbuminemia group were 3.5 times more likely to have poor neurologic outcome than were those in the normal albumin group (OR 3.526, 95% CI 1.388-8.956, p =0.008)., Conclusions: Hypoalbuminemia was common after CA, and the serum albumin level at admission was associated with poor neurological outcomes at 6 months after CA in patients treated with TTM., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this article., (Copyright © 2019 Soo Hyun Kim et al.)

Background: No tool is available for the multidimensional measurement of workplace well-being among Korean workers. In this study, the Workplace Positive emotion, Engagement, Relationships, Meaning, and Accomplishment (PERMA)-Profiler, a multidimensional workplace well-being measure, was translated into Korean, and its validity and reliability were assessed., Methods: The Workplace PERMA-Profiler, including the positive emotion, engagement, relationships, meaning, and accomplishment domains, was translated according to international guidelines. The questionnaires included the Workplace PERMA-Profiler, Mental Health Continuum-Short Form, Utrecht Work Engagement Scale, Maslach Burnout Inventory-General Survey, Psychosocial Well-being Index-Short Form, and Korean Occupational Stress Scale-Short Form. A total of 316 Korean workers completed a web-based survey with adequate response. Cronbach's alpha values were calculated to assess scale reliability, and correlational and confirmatory factor analyses were used to assess validity., Results: Cronbach's alpha values for the Korean Workplace PERMA-Profiler ranged from 0.70 to 0.95. Confirmatory factor analysis indicated that the 5-factor model had a marginally acceptable fit [χ 2 (80) = 383.04, comparative fit index = 0.909, Tucker-Lewis index = 0.881, root mean square error of approximation = 0.110, and standardized root mean square residual = 0.054]. The 5-factor PERMA domains were correlated positively with work engagement and mental well-being in life, and negatively with burnout, occupational stressors, and stress responses. These results showed that the Workplace PERMA-Profiler has good convergent and divergent validity., Conclusions: The Korean version of the Workplace PERMA-Profiler had good reliability and validity. It might be used as an indicator or evaluation tool for positive mental health interventions in the workplace., Competing Interests: Competing interests: The authors declare that they have no competing interests., (Copyright © 2019 Korean Society of Occupational & Environmental Medicine.)