Background: Research on the status of many chemicals used in the semiconductor industry is needed. The purpose of this study was to describe the overall status of chemical use in the semiconductor industry in Korea and to examine it from a health perspective. Methods: Data on the status of chemical use and safety data sheets at 11 of 12 major semiconductor workplaces in Korea were collected. The number of chemical products and chemical constituents, quantities of chemicals, and trade secret ingredients used, as well as the health hazards were examined. Results: On average, 210 chemical products and 135 chemical constituents were used at the surveyed workplaces. Among all chemical products, 33% (range: 16–56%) contained at least one trade secret ingredient. Most of the trade secret ingredients were used in the photolithography process. Several carcinogens, including sulfuric acid, chromic acid, ethylene oxide, crystalline silica, potassium dichromate, and formaldehyde were also used. Only 29% (39 of 135) of the chemical constituents had occupational exposure limits, and more than 60% had no National Fire Protection Association health, safety, and reactivity ratings. Based on the aforementioned results, this study revealed the following. First, many chemical products and constituents are being used in the semiconductor industry and many products contained trade secret ingredients. Second, many products contained significant amounts of carcinogenic, mutagenic, and reproductive toxicant materials. Conclusion We conclude that protecting workers in the semiconductor industry against harm from chemical substances will be difficult, due to widespread use of trade secret ingredients and a lack of hazard information. The findings of the status of chemical use and the health and safety risks in semiconductor industry will contribute to epidemiological studies, safe workplace, and worker health protection.

Background: Research on the status of many chemicals used in the semiconductor industry is needed. The purpose of this study was to describe the overall status of chemical use in the semiconductor industry in Korea and to examine it from a health perspective. Methods: Data on the status of chemical use and safety data sheets at 11 of 12 major semiconductor workplaces in Korea were collected. The number of chemical products and chemical constituents, quantities of chemicals, and trade secret ingredients used, as well as the health hazards were examined. Results: On average, 210 chemical products and 135 chemical constituents were used at the surveyed workplaces. Among all chemical products, 33% (range: 16–56%) contained at least one trade secret ingredient. Most of the trade secret ingredients were used in the photolithography process. Several carcinogens, including sulfuric acid, chromic acid, ethylene oxide, crystalline silica, potassium dichromate, and formaldehyde were also used. Only 29% (39 of 135) of the chemical constituents had occupational exposure limits, and more than 60% had no National Fire Protection Association health, safety, and reactivity ratings. Based on the aforementioned results, this study revealed the following. First, many chemical products and constituents are being used in the semiconductor industry and many products contained trade secret ingredients. Second, many products contained significant amounts of carcinogenic, mutagenic, and reproductive toxicant materials. Conclusion We conclude that protecting workers in the semiconductor industry against harm from chemical substances will be difficult, due to widespread use of trade secret ingredients and a lack of hazard information. The findings of the status of chemical use and the health and safety risks in semiconductor industry will contribute to epidemiological studies, safe workplace, and worker health protection.

Biofilms are commonly associated with an increased risk of catheter-associated infection. To study the efficacy of materials designed to reduce biofilm formation, microbial biofilms on clinically used urinary catheter were examined. We performed 2, 3-bis (2-methyoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay to determine of biofilm formation ability and observed with scanning electron microscopy (SEM) to analyze biofilm architecture. Additionally, we calculated relative cell surface hydrophobicity (CSH) to measure hydrophobicity of microorganisms. On SEM, catheter surfaces made of latex or anti-infective (IC)-latex were rough but those of silicone, hydrogel-coated silicone (HCS), or silver-alloy-coated silicone (SCS) were relatively smoother. According to XTT reduction assay, biofilm formation was reduced on the surface of smooth silicone-based catheters compared to rough latex-based catheters. The greatest to lowest formation of microbial biofilm were as follows for these material types: silicone-elastomer-coated (SEC) latex > latex > silicone > IC-latex > HCS > SCS. Catheter materials can affect the microbial biofilm formations. First, rougher surfaces on the catheter made the microbial attachment easier and a greater amount of biofilm was formed. Second, when chemicals that inhibit growth and attachment of microorganisms on the inner and outer surfaces of the catheters were applied, the biofilm formation was inhibited. SCS was found to be the most effective in reducing the microbial biofilm formation. These results indicate that microbial biofilm formation may be closely related to the surface roughness and microbial CSH.
Biofilms* ; Catheter-Related Infections ; Catheters ; Hydrophobic and Hydrophilic Interactions ; Latex ; Microscopy, Electron, Scanning ; Silicon ; Silicones ; Urinary Catheters*

Objective: The aims of this study were to explore the prevalence of and identify predictors of anxiety and depression related to coronavirus disease of 2019 (COVID-19) in South Korea. Methods: The analysis is based on a quota survey design and a sampling frame that permitted recruitment of a national sample of 1,014 individuals between March 17–31, 2020. Several standardized measurements were used, including GAD-7, PHQ-9, COVID-19 related fear, restrictions in deaily life, as well as sociodemographic information and physical and psychosocial needs during the pandemic. Multiple logistic regression was conducted to analyze the influence of sociodemographic factors, fear, and physical/psychosocial needs on anxiety and depression. Results: Significant numbers of the respondents were identifiable anxiety (19.0%) and depression group (17.5%), respectively. This indicates that the depression and anxiety prevalence rate after the COVID-19 is substantially high compared to the depression rate of 2.6% in 2020 and 2.8% in 2018 both reported in the Korea Community Health Survey and the anxiety rate of 5.7% reported in 2016 Survey of Mental Disorders in Korea. Multiple logistic regression results showed age, COVID-19 related fear, and the level of restrictions in daily as significant factors in understanding and predicting the anxiety group. Likfewise, the COVID-19 related fear, restrictions in daily life, and need for economic support were important predictors in predicting the depression group. Conclusion Findings on predictors for greater vulnerability to anxiety and depression has important implications for public mental health in the context of the COVID-19 pandemic.

Objective: The aims of this study were to explore the prevalence of and identify predictors of anxiety and depression related to coronavirus disease of 2019 (COVID-19) in South Korea. Methods: The analysis is based on a quota survey design and a sampling frame that permitted recruitment of a national sample of 1,014 individuals between March 17–31, 2020. Several standardized measurements were used, including GAD-7, PHQ-9, COVID-19 related fear, restrictions in deaily life, as well as sociodemographic information and physical and psychosocial needs during the pandemic. Multiple logistic regression was conducted to analyze the influence of sociodemographic factors, fear, and physical/psychosocial needs on anxiety and depression. Results: Significant numbers of the respondents were identifiable anxiety (19.0%) and depression group (17.5%), respectively. This indicates that the depression and anxiety prevalence rate after the COVID-19 is substantially high compared to the depression rate of 2.6% in 2020 and 2.8% in 2018 both reported in the Korea Community Health Survey and the anxiety rate of 5.7% reported in 2016 Survey of Mental Disorders in Korea. Multiple logistic regression results showed age, COVID-19 related fear, and the level of restrictions in daily as significant factors in understanding and predicting the anxiety group. Likfewise, the COVID-19 related fear, restrictions in daily life, and need for economic support were important predictors in predicting the depression group. Conclusion Findings on predictors for greater vulnerability to anxiety and depression has important implications for public mental health in the context of the COVID-19 pandemic.

Objective: This study aimed to observe the changes in people’s depressive levels over 9 months since the coronavirus disease of 2019 (COVID-19) outbreak as well as to identify the predictors of people’s depressive levels including COVID-19 infection fear in the context of South Korea in 2020. Methods: For these purposes, four cross-sectional surveys were periodically implemented from March to December 2020. We randomly recruited 6,142 Korean adults (aged 19 to 70) by using a quota survey. Along with descriptive analysis, which included a one-way analysis of variance and correlations, multiple regression models were built to identify the predictors of people’s depressive levels during the pandemic. Results Overall, people’s depressive levels and fear of COVID-19 infection gradually increased since the COVID-19 outbreak. In addition to demographic variables (i.e., being a female, young age, unemployed, and living alone) and the duration of the pandemic, people’s COVID-19 infection fear was associated with their depressive levels. Conclusion To ameliorate these rising mental health issues, access to mental health services should be secured and expanded, particularly for individuals who present greater vulnerabilities due to socioeconomic characteristics that may affect their mental health.

Background: The coronavirus disease 2019 (COVID-19) outbreak and subsequent disease-containment measures (such as school closures) significantly affected the lives of adolescents. We evaluated the mental-health status and factors associated with anxiety and depression among South Korean adolescents. Methods: A nationwide online survey was conducted to evaluate the mental-health status of South Korean adolescents during the COVID-19 pandemic. In total, 570 adolescents aged 13–18 years were surveyed between May 27 and June 11, 2021. The participants completed the Generalized Anxiety Disorder Scale (GAD-7) and Patient Health Questionnaire (PHQ-9) to determine anxiety and depression symptoms, respectively. Stepwise logistic regression models were constructed to determine factors related to anxiety and depression. Results: Among the study participants, 11.2% and 14.2% had anxiety and depression, respectively. The results suggested that several factors, such as the experience of COVID-19 infection and quarantine of oneself, a family member or an acquaintance, physical and mental health problems, and fear of one’s local community being discriminated against as a COVID-19 area were related to anxiety and depression. Conclusion The present study identified COVID-19-related factors associated with anxiety and depression among adolescents, and provides insights regarding potential interventions to improve the mental health of adolescents. To promote the mental health of adolescents during the COVID-19 pandemic, special attention should be paid to individuals with physical or mental-health problems, and efforts should be made to reduce the negative social and emotional impacts of infection-control measures.

PURPOSE: Following determination of the maximum standardized uptake values (SUVmax) of the mediastinal lymph nodes (SUV-LN) and of the primary tumor (SUV-T) on ¹⁸F-FDG PET/CT in patients with non-small-cell lung cancer (NSCLC), the aim of the study was to determine the value of the SUV-LN/SUV-T ratio in lymph node staging in comparison with that of SUV-LN.METHODS: We retrospectively reviewed a total of 289 mediastinal lymph node stations from 98 patients with NSCLC who were examined preoperatively for staging and subsequently underwent pathologic studies of the mediastinal lymph nodes. We determined SUV-LN and SUV-R for each lymph node station on ¹⁸F-FDG PET/CT and then classified each station into one of three groups based on SUV-T (low, medium and high SUV-T groups). Diagnostic performance was assessed based on receiver operating characteristic (ROC) curve analysis, and the optimal cut-off values that would best discriminate metastatic from benign lymph nodes were determined for each method.RESULTS: The average of SUV-R of malignant lymph nodes was significantly higher than that of benign lymph nodes (0.79±0.45 vs. 0.36±0.23, P<0.0001). In the ROC curve analysis, the area under the curve (AUC) of SUV-R was significantly higher than that of SUV-LN in the low SUV-T group (0.885 vs. 0.810, P= 0.019). There were no significant differences between the AUCs of SUV-LN and of SUV-R in the medium and high SUV-T groups. The optimal cut-off value for SUV-R in the low SUV-T group was 0.71 (sensitivity 87.5 %, specificity 85.9 %).CONCLUSIONS: The SUV-R performed well in distinguishing between metastatic and benign lymph nodes. In particular, SUV-R was found to have a better diagnostic performance than SUV-LN in the low SUV-T group.
Area Under Curve ; Humans ; Lung Neoplasms ; Lung ; Lymph Nodes ; Methods ; Positron-Emission Tomography and Computed Tomography ; Retrospective Studies ; ROC Curve ; Sensitivity and Specificity

PURPOSE: This study aimed to investigate the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG), which are volume-based PET parameters, using 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in patients with surgically resectable lung adenocarcinoma.METHODS: We retrospectively evaluated 149 patients with lung adenocarcinoma who underwent 18F-FDG PET/CT before surgical resection. Maximum standardized uptake value (SUVmax), MTV, and TLG of the primary tumor with threshold value of SUVmax 30, 40, and 50% were calculated, respectively. To compare the predictive performance of volume-based PET parameters, recurrence-free survival was assessed using the Kaplan-Meier method.RESULTS: The study included 70 males and 79 females with an average age of 65.8 years. The median follow-up time was 45.4 months. Recurrence was observed in 53 patients (35.6%). The mean ± SD SUVmax, MTV30%, and TLG(30%) of the entire cohort were 4.79 ± 2.94, 19.45 ± 24.85, and 56.43 ± 101.88, respectively. The cut-off values of MTV30% and TLG(30%) for recurrence were 11.07 ad 30.56, respectively. The 1-year recurrence-free survival (RFS) rate was 96.5% in low-MTV30% patients compared with 86.2% in high-MTV30% patients (p = 0.018) and 96.0% in low-TLG(30%) patients compared with 88.5% in high-TLG(30%) patients (p < 0.001). On univariate and multivariate analysis, TLG(30%) (HR, 2.828, p < 0.001; HR, 2.738, p < 0.001, respectively) was an independent prognostic factor for predicting recurrence-free survival (RFS).CONCLUSION: TLG(30%) value was observed to be a significant prognostic factor for RFS in patients with lung adenocarcinoma treated by surgical resection.
Adenocarcinoma ; Cohort Studies ; Electrons ; Female ; Fluorodeoxyglucose F18 ; Follow-Up Studies ; Glycolysis ; Humans ; Lung ; Male ; Methods ; Multivariate Analysis ; Positron-Emission Tomography and Computed Tomography ; Recurrence ; Retrospective Studies ; Tumor Burden

PURPOSE: This study aimed to investigate the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG), which are volume-based PET parameters, using 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in patients with surgically resectable lung adenocarcinoma. METHODS: We retrospectively evaluated 149 patients with lung adenocarcinoma who underwent 18F-FDG PET/CT before surgical resection. Maximum standardized uptake value (SUVmax), MTV, and TLG of the primary tumor with threshold value of SUVmax 30, 40, and 50% were calculated, respectively. To compare the predictive performance of volume-based PET parameters, recurrence-free survival was assessed using the Kaplan-Meier method. RESULTS: The study included 70 males and 79 females with an average age of 65.8 years. The median follow-up time was 45.4 months. Recurrence was observed in 53 patients (35.6%). The mean ± SD SUVmax, MTV30%, and TLG(30%) of the entire cohort were 4.79 ± 2.94, 19.45 ± 24.85, and 56.43 ± 101.88, respectively. The cut-off values of MTV30% and TLG(30%) for recurrence were 11.07 ad 30.56, respectively. The 1-year recurrence-free survival (RFS) rate was 96.5% in low-MTV30% patients compared with 86.2% in high-MTV30% patients (p = 0.018) and 96.0% in low-TLG(30%) patients compared with 88.5% in high-TLG(30%) patients (p < 0.001). On univariate and multivariate analysis, TLG(30%) (HR, 2.828, p < 0.001; HR, 2.738, p < 0.001, respectively) was an independent prognostic factor for predicting recurrence-free survival (RFS). CONCLUSION TLG(30%) value was observed to be a significant prognostic factor for RFS in patients with lung adenocarcinoma treated by surgical resection.