Development of Korean Head forms for Respirator Performance Testing

Seo, Hyekyung,Kim, Jennifer Ivy,Kim, Hyunwook Occupational Safety and Health Research Institute 2020 Safety and health at work Vol.11 No.1

Background: Protection from yellow dust and particulate matter is ensured by the use of respirators among the Korean citizens and workers. However, the manikins used to test the performance of the same were manufactured considering western facial specifications owing to which they do not represent Korean facial characteristics. Methods: Analysis of the data from the 6th 3D anthropometric survey of Koreans (Size Korea; 2010-2013) of 4,583 people aged 7 to 69 years was performed to obtain their facial dimensions. We subsequently clustered 44 facial measurements using Design X software, followed by the creation of the cluster centroid. Results: Three 3D head forms were developed-small, medium, and large, and their images were stored in ".stl" format for 3D printing. The facial widths and lengths of the three head forms were 127.1 mm × 90.6 mm, 143.2 mm × 104.0 mm, and 149.1 mm × 120.2 mm, respectively. Conclusion: We developed manikin head forms according to the facial dimensions of the Korean population, which was essential in evaluating respiratory protective equipment. These head forms can be used to test the performance of respirators considering the facial dimensions of the Korean population.

착용자 환경 및 시간에 대한 마스크 미생물 오염 연구

서혜경 ( Hyekyung Seo ),권영일 ( Young-il Kwon ),이성연 ( Seong Yeoun Lee ),강병갑 ( Byoung-kab Kang ),명준표 ( Jun-pyo Myong ),장호영 ( Hoyeong Jang ),김희주 ( Huiju Kim ),심수아 ( Sua Shim ),박성욱 ( Sungwook Park ) 한국산업보건학회 2021 한국산업보건학회지 Vol.31 No.4

Objectives: This study aims to investigate differences in microbial contamination according to the duration and environment of mask wearing. Methods: Forty-five participants were recruited from workers in an offices, multi-purpose facilities, and a schools. After wearing of KF94 mask for two. four, and six hours, the microorganisms adsorbed on the outer and inner layers of the mask were inoculated on BAP(Blood Agar Plate), Chocolate agar, and SDA plates. The bacterial count (CFUs: colony-forming units) cultured in each plate was measured and analyzed for changes in filtration efficiency. Results: The microbial contamination of masks worn in classrooms, offices, and multi-purpose facilities showed a significant difference depending on the environment (p<0.000). The measured CFUs increased significantly according to the time wearing the mask. The difference between the inner and outer layers of the mask was also significant (p<0.05). However, there was no statistical difference in the filtration efficiency of the masks by duration time (p=0.515). Conclusions: Masks worn by workers in the offices, multi-purpose facilities, and schools showed an increase of microbial contamination with the amount of time wearing the mask. The results indicate that the masks used in daily life may have adverse health effects if they are worn for a long time or reused over several days without the realizing that the masks can be contaminated with biological hazards. Guidelines on the safe threshold time for mask use should be established through further research.

Fit Test를 이용한 국내산 N95 마스크의 교육 후 밀착도 비교

서혜경 ( Hyekyung Seo ),권영일 ( Young-il Kwon ),명준표 ( Jun-pyo Myong ),강병갑 ( Byoung-kab Kang ) 한국산업보건학회 (구 한국산업위생학회) 2021 한국산업보건학회지 Vol.31 No.1

Objectives: A number of medical institutions have been conducting fit tests to perform seal checks on masks. This study aimed to compare the differences fit factor before and after domestic N95 mask-wearing training through a fit-test. Methods: A survey of 59 healthcare workers was conducted regarding whether they had undergone a fit test or received training on mask-wearing. Further, the fit of two types of domestic N95 masks was measured before and after the training using a QNFT(Quantitative Fit test). The average fit factors before and after training were compared using a paired t-test. Additionally the differences in the fit test pass rate were analyzed using a McNemar test. Results: A statistically significant difference was seen between the fit factors in the fit tests conducted before and after the training (p=0.0015), as well as in the fit of the two types of masks tested (p<0.01). Thus, an improvement in mask fitting was seen after the training, even with differently fitted masks. Conclusions: Upon using a QNFT, a significant increase in the fit factors for N95 masks was observed after training compared with masks that were fitted as usual. This highlights the importance of training in mask-wearing, with the conclusion that training healthcare providers will improve the fit of masks.

Examining a causal effect of private tutoring in Korea: does private tutoring damage students’ self-regulated learning?

Hyekyung Jung,Eun Hee Seo 서울대학교 교육연구소 2019 Asia Pacific Education Review Vol.20 No.3

Previous findings on the relationship between private tutoring and self-regulated learning are inconsistent. In this study, we assumed that the inconsistency of these findings was due to a combination of methodological issues, differing definitions of self-regulated learning and failure to account for the amount of time spent in private tutoring. The purpose of the study is to examine a causal effect of private tutoring on students’ self-regulated learning based on a social-cognitive perspective via the marginal mean weight through stratification method (MMW-S). We especially investigated if the effect of private tutoring varies depending on the quantity of private tutoring. Based on the hours of private tutoring per week, 3750 Korean middle school students were classified into six subgroups, and the population average causal effect of multivalued private tutoring was estimated with MMW-S. This finding indicated that private tutoring had a null effect on self-regulated learning across different levels of private tutoring, and no evidence was found that excessive private tutoring for academic subjects had a positive or negative impact on self-regulated learning. The findings imply that private tutoring itself neither progresses nor damages students’ self-regulated learning abilities.

<i>Spirodela polyrhiza</i> (L.) Sch. ethanolic extract inhibits LPS-induced inflammation in RAW264.7 cells

Seo, Chang-Seob,Lee, Mee-Young,Shin, In-Sik,Lee, Jin-Ah,Ha, Hyekyung,Shin, Hyeun-Kyoo Informa Healthcare 2012 IMMUNOPHARMACOLOGY AND IMMUNOTOXICOLOGY Vol.34 No.5

<P><I>Objective</I>: <I>Spirodela polyrhiza</I> (L.) Sch. is widely used in Korean traditional medicine. No previous work has investigated in detail the anti-inflammatory activities of <I>S. polyrhiza</I> or assessed <I>in vitro</I> their potential underlying mechanism(s). We assessed the effects of <I>S. polyrhiza</I> ethanolic extract (SPEE) on the production of inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and investigated some potential underlying mechanisms. Additionally, we performed simultaneous determination of seven flavonoids in <I>S. polyrhiza</I> by high-performance liquid chromatography (HPLC)-photodiode array (PDA).</P><P><I>Materials and methods</I>: RAW264.7 cells were subjected to 5, 10, 20, and 50 μg/mL of SPEE for 1 h then treated with LPS for 24 h. Production of namely nitric oxide (NO), prostaglandin E<SUB>2</SUB> and cytokine levels were measured by the Griess reagent and ELISA, respectively. To investigate the underlying mechanisms of the anti-inflammatory activities of SPEE, expression of NO synthase (iNOS), cyclooxygenase-2 (COX-2), and nuclear factor-kappa B (NF-κB) proteins were evaluated by western blot analysis. HPLC analysis was performed using a Gemini C<SUB>18</SUB> column at 40°C and PDA detection at 340 nm.</P><P><I>Results</I>: SPEE treatment significantly inhibited the LPS-induced production of NO, prostaglandin E<SUB>2</SUB>, interleukin-6, and tumor necrosis factor-α and inhibited the expression of iNOS and COX-2 via attenuation of NF-κB p65 expression. The contents of the seven flavonoids in <I>S. polyrhiza</I> range from 0.25 to 8.77 mg/g.</P><P><I>Conclusions</I>: These results indicate that the anti-inflammatory activity of SPEE may be NF-κB p65 signaling. Also, the method will help to improve quality control of <I>S. polyrhiza</I>.</P>

Vibrio sp. dhg; A Novel Promising Microbial Platform for the Biorefinery of Brown Macroalgae

Hyekyung LEE,Hyun Gyu LIM,Dong Hun KWAK,Sungwoo PARK,Sunghwa WOO,Sang Woo SEO,Gyoo Yeol JUNG 한국생물공학회 2022 한국생물공학회 학술대회 Vol.2022 No.4

Efficient Brown Macroalgae Biorefinery Using Non-edible Biomass and Engineered Vibrio sp. dhg

HyeKyung LEE,Sung Hwa WOO,Hyun Gyu LIM,Dong Hun KWAK,Sungwoo PARK,Sang Woo SEO,Gyoo Yeol JUNG 한국생물공학회 2023 한국생물공학회 학술대회 Vol.2023 No.10

Establishment of minimal positive-control conditions to ensure brain safety during rapid development of emergency vaccines

Baek, Hyekyung,Kim, Kwang Ho,Park, Min Young,Kim, Kyeongryun,Ko, Bokyeong,Seo, Hyung Seok,Kim, Byoung Soo,Hahn, Tae-Wook,Yi, Sun Shin The Korean Society of Veterinary Science 2017 Journal of Veterinary Science Vol.18 No.-

<P>With the increase in international human and material exchanges, contagious and infectious epidemics are occurring. One of the effective methods of epidemic inhibition is the rapid development and supply of vaccines. Considering the safety of the brain during vaccine development is very important. However, manuals for brain safety assays for new vaccines are not uniform or effective globally. Therefore, the aim of this study is to establish a positive-control protocol for an effective brain safety test to enhance rapid vaccine development. The blood-brain barrier's tight junctions provide selective defense of the brain; however, it is possible to destroy these important microstructures by administering lipopolysaccharides (LPSs), thereby artificially increasing the permeability of brain parenchyma. In this study, test conditions are established so that the degree of brain penetration or brain destruction of newly developed vaccines can be quantitatively identified. The most effective conditions were suggested by measuring time-dependent expressions of tight junction biomarkers (zonula occludens-1 [ZO-1] and occludin) in two types of mice (C57BL/6 and ICR) following exposure to two types of LPS (<I>Salmonella</I> and <I>Escherichia</I>). In the future, we hope that use of the developed positive-control protocol will help speed up the determination of brain safety of novel vaccines.</P>

프랑스 한글학교 계승어 학습자의 한국어 학습 동기와 태도 연구: 한국인 가정과 다문화 가정 아동의 비교를 중심으로

박혜경 ( Hyekyung Park ),서진숙 ( Jinsuk Seo ) 성결대학교 다문화평화연구소 2016 다문화와 평화 Vol.10 No.2

이 연구는 프랑스 한글학교의 한국인 가정과 다문화 가정의 한국어 계승어 학습자를 대상으로 그들의 한국어 학습 동기와 태도를 조사, 확인하여 두 학습자 집단 간에 차이를 밝히는 데 첫 번째 목적이 있다. 또한 두 학습자 집단의 차이를 토대로 한글학교에서 한국어 수업을 효과적으로 운영하는 방안을 제안하는 데 목적이 있다. 이에 이 연구에서는 한국인 가정과 다문화 가정이 비교적 균질하게 분포한 프랑스 소재 한글학교의 아동 학습자를 대상으로 한국어 학습 동기와 태도에 대해 조사를 실시하였다. 그 결과 한국인 가정의 아동의 학습 동기는 정체성, 가족 관련, 자기 개발, 외적 압력 동기로 다양하게 가지고 있는 반면 다문화 가정의 아동은 정체성과 가족 관련 동기로 압축되어 나타났다. 또한 태도에 있어서 한국인 가정 아동은 일반 한국어 모어 화자들과 유사한 수준의 한국어 능력에 도달하고자 하는 의지가 강했지만 다문화 가정 아동의 경우 그러한 수준까지는 크게 동의하지 않았다. 반면 한국어 학습 의지나 만족도는 다문화 가정 아동이 한국인 가정의 아동보다 높게 나타났다. 이 두 집단은 학습 동기와 태도에 있어서 차이를 보이므로 학급을 분리하여 한국어 수업을 운영하는 것이 가장 이상적이지만 학습자 변인에 따라 다양한 학급 구성이 어려운 한글학교의 현실을 감안하여 본 논문에서는 교육 내용 선정 및 교육 수준, 목표 설정에 차이를 두어 수업을 운영하는 방안을 제안하였다. This study surveyed the attitude and learning motivation of Korean students of Korean families and Korean language heritage students of multicultural families. The first aim was to discover the differences between the two groups. Also, the aim was to suggest an effective method to teach Korean lessons in Korean language schools based on the differences between these two groups. Therefore, in this study, Korean families and Korean language heritage learners of multicultural families were the subject of this study and in this study, for a comparison of Korean families and multicultural families, a uniform distribution of French material survey was completed on the Korean language schools`` child learners`` motivation to learn Korean and their attitude toward learning. As for the result, children of Korean families were found to have identity, family related, personal development, external pressure and various motivation whereas, multicultural family children``s motivation was compressed into identity and family related motivation. Also, in the case of children of Korean families, there was a strong determination to reach a level of competence similar to those of the general Koreans but in the case of multicultural family children, such levels were not as significantly accepted. On the other hand, multicultural family children were found to have higher determination and satisfaction regarding Korean learning. The two groups show a difference in learning motivation and their attitude toward learning. Therefore, it is most rational to separate their learning but the reality that it is difficult for Hangeul School to configure a class based on student variations was considered and in this paper, selection of educational content and level of education, by making a difference in goal setting, was proposed as a plan to teach the class.

수변경관 이용 활성화를 위한 자연형 하천 이용행태 및 만족도

하혜경 ( Hyekyung Ha ),서자유 ( Jayoo Seo ) 한국경관학회 2021 한국경관학회지 Vol.13 No.1

본 연구는 하천법 전면 개정 이후 친환경 하천계획 수립에 따라 복원된 자연형 하천을 대상으로 지역민들의 하천 이용행태 및 만족도 조사를 실시하였다. 이는 기존의 하천 자체의 환경과 생태자원에 대한 접근에서 지역민 참여와 프로그램 참여 등 자연형 하천의 수변경관 이용을 활성화하는데 목적이 있다. 연구 방법으로는 자연형 하천 유형에 따라 지역하천, 근린하천, 소하천으로 구분하여 각 하천별로 50명을 대상으로 총 291명 대상의 설문조사를 실시하였다. 연구결과 첫째, 자연형 하천은 지역하천, 근린하천, 소하천 등 하천의 규모와 길이, 고수부지의 상황에 따라 지역민들의 이용행태와 요구사항이 상이하므로 자연형 하천의 수변계획시 하천유형에 따라 구분하여 계획할 필요가 있다. 둘째, 조깅로, 운동공간, 체육시설 등 운동공간이 많은 규모가 큰 하천 일수록 만족도가 높았으며, 활동적인 운동시설에 요구도가 높고, 장시간 이용자가 많으므로 이에 대응하는 조경시설이 요구된다. 셋째, 자연형 하천이 소하천의 경우는 고수부지가 협소하고 수목량과 그늘이 부족하여 휴식시설 등에 대한 요구도가 높게 나타났는데, 추후 소하천의 수변공간에 세심한 계획이 필요하다. 본 연구는 자연형 하천의 수변환경을 개선하기 위한 기초자료로 주민들의 인식조사를 통해 하천 이용행태 및 만족도 조사를 실시함으로써 기존의 자연형 하천 연구가 수질, 수량, 동·식물 환경조사 등 생태환경연구에 치중하였던 것을 한계로 삼아 도심 내에서 자연형 하천의 수변경관 이용을 보다 활성화하기 위한 방안으로 자연형 하천 수변계획시 기초자료로서 의미가 있다. 그러나, 6개의 하천이 전국의 지방하천, 근린하천, 소하천을 대표하기에는 한계가 있으므로 연구 표본을 확대할 필요가 있다. This study conducted a survey on river usage behavior and satisfaction of local residents on natural rivers restored according to the establishment of eco-friendly river plans after the complete revision of the River Law. This aims to revitalize the use of natural rivers, such as local residents’ participation and program participation in access to the environment and ecological resources of the existing river itself. As a research method, according to the type of natural river, it was classified into regional rivers, neighboring rivers, and small rivers, and a total of 291 people were surveyed for 50 people for each river. This study conducted a survey on river usage behavior and satisfaction of local residents on natural rivers restored according to the establishment of eco-friendly river plans after the complete revision of the River Law. This aims to revitalize the use of natural rivers, such as local residents’ participation and program participation in access to the environment and ecological resources of the existing river itself. As a research method, according to the type of natural river, it was classified into regional rivers, neighboring rivers, and small rivers, and a total of 291 people were surveyed for 50 people for each river. As a result of the study, first, natural type rivers are comprehensively conceived such as rivers, waterside land use, and park green areas in the planning stage, but they are separated in the detailed design stage, and the consistency of river and waterfront planning is not maintained. Second, natural type rivers have different usage behaviors and requirements depending on the size and length of rivers such as regional rivers, neighboring rivers, and small rivers, and the situation of the reservoir site, so it is necessary to separate and plan the waterfront plans of natural type rivers. Third, in the case of small rivers of natural type rivers, the demand for rest facilities is high because the high water site is narrow and the amount of trees and shade is insufficient, while the demand for active sports facilities is high in rivers with large river sizes such as neighboring rivers or regional rivers. It is high and there are many users for a long time, so a landscaping facility corresponding to this is required. This study is the basic data for improving the water conversion landscape of natural type rivers, and by conducting a survey on river usage behavior and satisfaction through residents’ perception survey, the existing natural river research is based on ecological environment such as water quality, quantity, animal and plant environment survey. It is a method to further revitalize the watersides of natural rivers within the city, taking the focus on research as a limit, and is meaningful as basic data when planning natural rivers. However, it is necessary to expand the research sample because six rivers are limited to represent local, neighboring and small rivers nationwide.