Jeonghoon Kim

Enantioselective synthesis of (2R,3S)-(+)-catechin

Abstract A new enantioselective synthetic method for catechin from trans-methyl cinnamate derivative was developed via asymmetric dihydroxylation (ADH), the addition of an aryllithium species, followed by the Barton–McCombie reaction and an intramolecular Mitsunobu reaction as key steps.

Enantioselective synthetic method for 3-hydroxyflavanones: an approach to (2R,3R)-3′,4′-O-dimethyltaxifolin

A new enantioselective synthetic method for (2R,3R)-3-hydroxyflavanone (1a) was developed via asymmetric dihydroxylation (ADH) and intramolecular Mitsunobu reaction as key reactions and the application to synthesis of (2R,3R)-3′,4′-O-dimethyltaxifolin (1b) is described.

Air Quality, Biomarker Levels, and Health Effects on Staff in Korean Restaurants and Pubs Before and After a Smoking Ban

INTRODUCTION The Korean government implemented a smoking ban at square floor area of ≥150 m(2), rather than <150 m(2), restaurants and pubs from July 2013. This study examined the effects of the smoking regulations in restaurants and pubs in terms of the air quality, biomarker levels and health effects on staff. METHODS Particulate matter smaller than 2.5 µm (PM2.5) was measured in 146 facilities before and 1 month after the ban. The urinary cotinine and 4-(methylnitrosamino)-1-(3-pyridyl)-1- butanol (NNAL) levels were measured in 101 staff members at 77 facilities before and 1 month after the ban. We also measured self-reported respiratory and sensory symptoms on both phases. RESULTS Of the 146 facilities, 121 facilities were included in the PM2.5 analysis. In ≥150 m(2) pubs, the indoor PM2.5 concentration was significantly reduced after the ban (p < .05). While the urinary cotinine concentrations of the staff in all facilities were not changed after the ban, the total NNAL concentrations of the staff in ≥150 m(2) pubs were significantly reduced after the ban (p < .05). The health effects on staff show that only sensory symptoms significantly improved in ≥150 m(2) facilities after the ban (p < .05). CONCLUSIONS The smoking ban significantly reduced the levels of PM2.5 and total NNAL concentrations in ≥150 m(2) pubs and improved sensory health among staff in ≥150 m(2) facilities. The results of this study can be useful in supporting an expansion of the smoking ban in all indoor places, including <150 m(2) restaurants and pubs.

Indoor PM 2.5 Concentrations in Different Sizes of Pubs with Non-comprehensive Smoke-free Regulation

Objectives: The Korean government implemented a smoke-free regulation for pubs with a net indoor area of ≥100 m on January 1, 2014. The purpose of this study was to determine the indoor levels of concentrations of particulate matter smaller than 2.5 μm (PM2.5) in implemented and non-implemented pubs in Seoul and Changwon. Methods: PM2.5 concentrations in fifty-two 100-150 m 2 (implemented) and fifty-seven <100 m (nonimplemented) pubs were measured. A real-time aerosol monitor was used to measure PM2.5 concentrations. Field technicians recorded characteristics of the pubs including net indoor area, indoor volume and presence of smoking rooms and counted the number of burning cigarettes, patrons and vents. Results: Differences between indoor and outdoor PM2.5 concentrations in 100-150 m 2 and <100 m pubs were not significantly different in each city. Smoking was observed in 33% of 100-150 m pubs and 51% of <100 m pubs. Average differences between indoor and outdoor PM2.5 concentrations in the 100-150 m 2 and <100 m pubs were 79.2 μg/m and 155.6 μg/m, respectively. When smokers were not observed, differences between indoor and outdoor PM2.5 concentrations ware 12.4 μg/m 3 in 100-150 m pubs and 24.5 μg/m in <100 m pubs. Conclusion: Although the regulation was implemented only in ≥100 m pubs, a higher difference between indoor and outdoor PM2.5 concentrations was observed in implemented and non-implemented pubs with smokers. Strict implementation of the regulation in all pubs is needed for better indoor air quality.

Relationships Between Secondhand Smoke Incursion and Wheeze, Rhinitis, and Eczema Symptoms in Children Living in Homes Without Smokers in Multi-Unit Housing

INTRODUCTION Secondhand smoke (SHS) incursion can occur in units of multi-unit housing (MUH). The purpose of this study was to determine the relationship between SHS incursion and allergic symptoms in children living in MUH without smokers. METHODS We conducted a cross-sectional study from May to September 2015 in Seoul, Korea. Children were recruited from elementary schools, kindergartens, and daycare centers. In total, 16676 children between 1 and 13 years of age living in MUH without smokers were included in the analysis. Allergic symptoms during the previous 12 months (current wheeze, rhinitis, and eczema) and home environmental factors, including the frequency of SHS incursion during the previous 12 months, were examined using a questionnaire filled out by the parents or guardians of the children. RESULTS The prevalence of current allergic symptoms in children was 4.9% for wheeze, 42.0% for rhinitis, and 28.1% for eczema. The prevalence of SHS incursion into the childrens homes was 61.6%. In a multivariable logistic regression analysis adjusted for demographic and home environmental factors, children living in homes with SHS incursion (either no more than once a month or more than once a month) were more likely to have current wheeze, rhinitis, and eczema than those with no SHS incursion. CONCLUSIONS More than half of the childrens homes in MUH without smokers had SHS incursion. SHS incursion into homes was associated with wheeze, rhinitis, and eczema symptoms in children. IMPLICATIONS Children living in multi-unit housing (MUH) can be exposed to secondhand smoke (SHS) from smoke transferred from neighboring units with smokers. This study found that more than half of the childrens homes without smokers in MUH had SHS incursion. Children living in homes with SHS incursion (either no more than once a month or more than once a month) were more likely to have current wheeze, rhinitis, and eczema than those with no SHS incursion. We confirmed that SHS incursion was associated with allergic symptoms in children.

Relationship between exposure to second-hand smoke in the workplace and occupational injury in the Republic of Korea

Background Most studies in the field of smoking exposure in the workplace linked to occupational safety have only focused on active smoking. Few studies have reported that exposure to second-hand smoke in the workplace is a possible factor increasing the risk of occupational injury without considering occupational characteristics. The aim of this study was to determine the association between occupational injury and level of exposure to second-hand smoke at the workplace among Korean workers, after taking into account occupational characteristics. Method Using data from the third Korean Working Conditions Survey, levels of exposure to second-hand smoke were categorized as none, moderate, and high. We investigated the influence of exposure to second-hand smoke on occupational injury using logistic regression analysis with stratification by sex, smoking status, smoke-free policy in the workplace, and occupational characteristics. Occupational characteristics (occupational classification, working schedule, length of working day, and co-exposure to occupational hazards in the workplace) were stratified and analyzed using logistic regression models to estimate the risk of occupational injury linked to exposure to second-hand smoke. Results Among all participants, there was a significant dose-dependent association between risk of occupational injury and level of exposure level to second-hand smoke. After stratification by sex and smoking status, there was a significant association between risk of occupational injury and exposure level to second-hand smoke. Moreover, there was a significant relationship between exposure to second-hand smoke in the workplace and occupational injury, depending on the smoking-free policy at workplace (odds ratio [OR] in completely non-smoking workplace, 4.23; OR in non-smoking workplace with separate smoking area, 2.98; OR in smoking workplace 2.84). Additionally, there was a significant relationship between risk of occupational injury and exposure to second-hand smoke after stratification by occupational classification, working schedule, long working hours, and co-exposure to hazards in the workplace. Discussion There was a dose-response relationship between occupational injury and exposure to second-hand smoke, even after stratification to reduce the impact of various potential confounders and after taking into account occupational characteristics. These findings provide greater insight into the effects of exposure to second-hand smoke on the working population and may direct further research and policy-making in this field.