This study conducted a survey on environmental awareness and analyzed outdoor PM10 and heavy metals (cadmium, lead) for 60 local residents living in the Gwangyang national industrial complex from July 2019. 40.0% of subjects responded that local environmental pollution was serious. Especially, there was a high proportion of residents living near the industrial complex or roads where it was perceived that local environmental pollution was serious. The average concentration of PM10 in the outdoors of the houses was 10.95 μg/m3 and the average concentration of heavy metals in PM10 was 1.90 ng/m3 for Cd and 24.92 ng/m3 for Pb. Overall, the average concentration of PM10 and heavy metals revealed a tendency to be high in the houses located near the industrial complex or the roads. As a result of a risk assessment carried out, the cancer risk of Cd was estimated to exceed 106 in the CTE, RME and Monte Carlo analysis. These results suggest that the urgent implementation of specific environmental health education for local residents is necessary.

In the manufacturing industry, sparks occur during operation due to collisions of metals, and strong sparks and arcs are generated even during welding works. X-rays are generated when high-speed electrons from outside collide with electrons in a metal. Thus, the objective of this study proposes the risk of sparks and arcs that can generate X-rays. We developed the spark generator using the electrostatic principle and constructed the arc generating device using the high voltage. The X-rays are measured when sparks and arcs are continuously generated between the anode metal target and the cathode metal. The measured X-rays were found to be harmful to humans when exposed for a long period. Therefore, workers exposed to workplaces with frequent sparks and arcs need to protect themselves.

The reliability of the lifting system has to be ensured so that heavy cargo is handled safely during loading and unloading. Therefore, the accelerated life test was performed on the lifting bow shackle, which is highly affected by the main failure mode, among the components of the lifting system. Besides, an efficient inspection method was suggested for the preventive maintenance of the bow shackles. The acceleration index and acceleration coefficient of the bow shackles were calculated by using the life data of them. The guaranteed life data of the bow shackle can be used to predict the useful life in industries related to lifting work.

In this study, 38 residents of the Jeonnam areas in Korea were assessed for their level of exposure to VOCs. The aim was to understand the difference in levels of indoor, outdoor, and personal exposure to VOCs (benzene, toluene, ethylbenzene) and a health effect assessment was conducted to determine whether there was any fatal cause from carcinogenic or non-carcinogenic elements from case and control group. Personal exposure to benzene showed a higher distribution than indoor and outdoor concentrations, and it was found that the average concentration of the case group was higher than that of the control group in all indoor, outdoor, and personal exposures. With regard to benzene, in the CTE, RME, and Monte-Carlo analysis, all subjects in the case group were seen to exceed the lifetime cancer risk of 10−6 defined by the US EPA and in the RME analysis the control group subjects were also seen to exceed the lifetime cancer risk of 10−6 defined by the US EPA. In the case of toluene, ethylbenzene on the CTE, RME, and Monte-Carlo analysis, the non-carcinogenic standard of 1 was not exceeded.

Aloin [1,8-Dihydroxy-10-(β-D-glucopyranosyl)-3- (hydroxymethyl)-9(10H)-anthracenone]은 알로에에서 추출한 천연 안트라퀴논이다. 다양한 유형의 인간 암세포에서 항산화, 항암 효과가 있는 것으로 밝혀졌지만 인간 대장암 세포 HT-29에서 aloin의 항암 효과는 밝혀지지 않았다. 본 연구에서는 aloin이 인간 대장암 HT-29 세포에서 세포 사멸 작용을 발휘할 수 있는 메커니즘을 조사하였다. Aloin 이 세포 생존율에 영향을 미치는지 알아보기 위해 대장암 세포 HT-29, 흑색종 세포 A375SM, 위암 세포 AGS를 aloin(0, 100, 200, 300 및 400 μM)으로 처리하였을 때, HT- 29에서는 농도 의존적으로 세포 생존율을 감소시켰고, A375SM과 AGS 세포에서는 암세포 생존율의 감소가 보이지 않았다. 이러한 HT-29에서의 세포 생존율 감소가 세포자멸사로 인한 감소인지 확인하기 위해 DAPI stain과 flow cytometry를 실시한 결과 apoptotic body가 유의적으로 증가하고 세포 자멸사가 증가한 것을 확인할 수 있었다. 이와 같은 결과를 바탕으로 aloin이 대장암 세포 HT- 29에서 세포 사멸 관련 단백질 발현 양상에 미치는 영향을 확인하기 위해 western blotting을 실시하였다. Aloin은 Bax, PARP의 분절을 농도 의존적으로 증가시켰고, caspase- 3, -8을 활성화시켰지만, Bcl-2는 대조군에 비해 변화가 없었다. Aloin에 의해 유도된 세포자멸사 기전을 확인하기 위해 MAPK pathway 중 p-p38과 p-ERK의 발현을 확인한 결과, p-p38을 up-regulation시키고 p-ERK의 downregulation을 유도했다. 따라서, aloin은 인간 대장암에서 암 세포 성장 억제 효과 및 암세포 사멸 유도로 암예방 약제로서의 개발 가능성이 있다고 사료된다.

In this study, 102 residents in Gwangyang and Yeosu were evaluated for exposure to levels of urethral arsenic from April 2017 to June 2018. The geometric mean concentration of the urinary arsenic in the total studied was 154.30 μg/L, with the figure for the Gwangyang area being 201.18 μg/L and the figure for the Yeosu area being 200.21 μg/L, which signifies that there was no real difference between the two regions. The figures for males and females were 173.81 μg/L and 136.98 μg/L, respectively, indicating higher levels for males. In the case of males, the risk assessment of arsenic (As) showed that 0.54 does not exceed 1 and approximately 11.3% exceeded the reference value. For women, the number of hazardous materials did not exceed 1.41 and approximately 5.1% exceeded the reference value of the total arsenic exposure survey.

This study evaluated the physicochemical and microbial quality characteristic of seasonal commercial kimchi for hygienic safety levels. The pH of seasonal commercial kimchi was 3.84-6.36 and the titratable acidity and salinity of the samples were 0.21-1.16 and 1.19-1.54%, respectively. The content of nitrate and nitrite in the commercial kimchi were lower in the spring and summer, which was affected by acidic condition of the kimchi depending on fermentation. Heavy metal contents in commercial kimchi are not an issue because they were detected only at very low levels. The total aerobic bacteria and coliforms counts ranged from 5.25 to 8.44 Log CFU/g and 0.00 to 5.08 Log CFU/g, respectively. The total aerobic bacteria and coliforms were detected more in summer than in the other seasons. E. coli was detected in three of the samples tested. Food-borne pathogens were not detected in any of the samples except for B. cereus. B. cereus was detected in the fall in more than 70% of samples. These results suggest that commercial kimchi distributed in the fall maintain the quality properties and the microbiological safety of kimchi compared to the other seasons. Therefore, further studies as an effective distribution system for the particular seasons will be needed to guarantee the hygienic safety levels of commercial kimchi required by the consumers.

우르솔릭산은 항암, 항산화, 항염증 작용과 같은 다양한 효과를 지니고 있다. 본 연구에서는 우르솔릭산이 인간 흑색종 암세포인 A375SM과 A375P 세포에 항암효과가 있는지 확인하였다. 두 세포의 생존율은 MTT assay를 통하여 확인하였으며 증식률은 Wound healing assay로 확인하 였다. 두 세포의 apoptotic body와 apoptosis 비율의 확인을 위한 DAPI 염색과 유세포 분석을 진행하였다. 그리고 웨스턴 블로팅을 통하여 흑색종 세포의 우르솔릭산의 농도에 따른 apoptosis 단백질의 유도를 조사하였다. 우르솔 릭산의 처리 농도에 따라 흑색종 세포의 생존율 감소와 증식률 감소를 확인하였다. DAPI 염색을 통하여 우르솔 릭산의 농도가 증가함에 따라 흑색종 세포의 염색체 응축 이 농도 의존적으로 증가하였고, 유세포 분석을 통하여 우르솔릭산에 대하여 농도 의존적으로 흑색종 세포의 apoptosis 비율의 증가를 확인하였다. 그리고 웨스턴 블로팅을 통해 흑색종 세포 A375SM과 A375P의 우르솔릭산 12 μM 농도에서 cleaved-PARP와 Bax의 증가와 Bcl-2의 감소를 확 인하였다. 본 연구는 우르솔릭산의 농도를 0 에서 20 μM 수준의 저농도에서 진행하였으며, 물질 처리 후 24 시간 뒤 결과를 가지고 분석하였다. 본 연구의 결과로 보아 우르솔릭산은 흑색종 세포 A375SM과 A375P에서 apoptosis 관련 단백질들의 조절을 통해 항암효과를 일으키는 것으로 사료된다.

PURPOSES : Recently, there has been an increase in the use of discrete randomly distributed fiber materials for reinforcing pavement foundations. However, very limited study has been made on this from the perspective of pavement engineering. Therefore, this study evaluates the performance of soil-geofibers used in pavement foundations as well as the effects of stress dependency with various mixtures. METHODS: To estimate the behavior of soil-geofiber mixtures under traffic loadings, laboratory resilient modulus data for the mechanical characteristics of geofiber mixtures were used, and they were adopted to evaluate the structural response and analyze the stress dependency through 2-D finite element analysis. As the host materials, poorly graded and uniformly graded sand were selected, and each soil was mixed with three different types of fiber, namely monofilament, fibrillated, and tape. RESULTS: The stress dependent response on resilient modulus and Poisson’s ratio were mainly considered by conducting linear and nonlinear elastic analyses on various geofiber mixtures. As a result, it was found that the response and yield function of geofiber mixed layers in pavements were affected considerably depending on the gradation of the soils and the confinement conditions. A small change was found when the particle size was homogenized. CONCLUSIONS : From this, it can be concluded that the finite element model with stress dependency is suitable for estimating the performance on geofiber mixtures. It is also noted that all the responses of geofiber mixtures were relatively sensitive to the gradation of host soils. This indicates that the effects of the nonlinearity and stress-dependency of geofiber mixtures under repetitive loadings could be substantial.

In this study, 40 residents of the Gwangyang and Yeosu areas were assessed for their level of exposure to heavy metals (As, Cd, Ni) from April 2017 to June 2018. The aim was to understand the differences in levels of indoor exposure to heavy metals (As, Cd, Ni), and a health risk assessment was conducted to determine whether there was any fatal cause from carcinogenic elements. The mean concentrations of PM10 particles indoors were As 0.24 μg/m3, Cd 0.07 μg/m3, and Ni 0.89 μg/m3. The health risk assessment for the arsenic, cadmium, and nickel in indoor air confirmed that the mean values exceeded the cancer risk tolerances specified by the U.S. EPA, for As (males 3.07 × 10−4, females 3.35 × 10−4), Cd (males 3.83 × 10−5, females 4.18 × 10−5), and Ni (males 6.36 × 10−5, females 6.95 × 10−5).

유럽에서 양송이 야외발효에 많이 사용하던 윈드로우터너를 우리나라 실정에 맞게 밀짚대신 볏짚을 사용할 수 있도록 개량 개발하였다. 관행 굴삭기작업과 비교하여 조사한 결과는 다음과 같다. 교반작업 성능은 81 m3 /hr으로 굴삭기 28.6 m3 /hr보다 2.8배 높았으며, 재배사 한 동(균상면적 165 m2 )당 1회 배지교반시간이 46분으로 관행보다 노력을 66% 절감할 수 있는 것으로 분석되었다. 또한 야외발효 말기 배지더미의 온도분포 조사 결과 배지더미 중앙 아래부분의 온도가 관행보다 5℃ 이상 높아 호기발효에 유리한 것으로 나타났으며, 부숙도를 추정할 수 있는 회분조사결과 30.9±1.1%로 나타나 관행 28.4±1.6%보다 부숙정도도 높게 나타났다. 버섯의 농가 재배결과 수확량이 시작기의 경우 관행 대조구 대비 22.9% 증수되는 것으로 나타났다.