Outdoor air pollution with particulate matter has become more severe in Korea. Ambient particle concentration affects the indoor environment through various routes through building envelopes. In this study, we investigated particle exposure in residential buildings. Indoor and outdoor particle sources determined the indoor concentrations and particle exposure. This paper measured indoor particles and CO2 concentrations in two different apartment buildings and conducted the survey for 24 hours. The I/O ratio of the occupant awake period was higher than the asleep period. The I/O ratio in the awake period is 0.93-3.65, while the I/O ratio in the asleep period is 0.31- 0.76.Indoor peak events such as cooking or cleaning temporarily increase the I/O ratio and emit the indoor particle sources. Decay rate constant is 0.49-6.84 (1/h) in the indoor peak events during the operation of the exhaust hood and natural ventilation. The size range of 0.3-0.5 μm size is over half for the proportions of emitted particles (55.6%). Daily exposure is divided into indoor sources (45.2%) and outdoor sources (54.8%). We found the differences for the proportion of particle exposure. The ratio of daily exposure in particles for 0.3-0.5 μm size is 43.1 (indoor)/ 56.9 (outdoor) %. However, indoor sources are higher than outdoor sources for the ratio of daily exposure in particles for the 0.5-10.0 μm size.

인간의 인위적 활동으로 인해 발생하는 중금속 중 카드 뮴 (Cd)과 아연 (Zn)은 다양한 경로를 통해 하천으로 유입 되어 서식생물에게 유해 영향을 준다. 본 연구에서는 도심 하천에서 우점하는 장수깔따구 (Chironomus plumosus)를 이용하여 Cd와 Zn 노출에 따른 생태독성학적 반응을 연구 하였다. 생활사를 고려하여, 생존율, 성장율, 우화율, 성비와 하순기절 기형을 관찰하였다. 장수깔따구 생존율은 Cd 와 Zn 노출에 따라 시간, 농도의존적인 경향을 나타냈다. 성장율은 Cd 노출 후 Day 4와 Day 7, 농도의존적인 감소를 보였으며, 고농도인 50 mg L-1에서 대조군에 비해 급격한 감소를 나타냈다. 또한, 우화율은 10, 50 mg L-1 Cd에서 대조군에 비해 감소함을 관찰하였다. 성비 변화는 100 mg L-1 Zn에서 암컷의 비율이 증가였으나 농도가 높아짐에 따라 수컷의 비율이 높아짐을 보이며 성비불균형이 관찰되었다. 게다가, 장수깔따구의 하순기절에서는 대조군에 비해 Cd와 Zn 노출된 장수깔따구에서 기형이 관찰되었다. 이와 같은 결과는 수생태계로 유입되는 중금속이 하천의 하상저층에 서식하는 저서무척추동물에게 유해한 영향을 주며, 중금속 노출에 따른 생물학적 분석을 위한 현장 지표 종으로서의 가능성을 보여주었다.

휴전국인 우리나라는 의무복무제도를 시행하고 있다. 이에 취업 및 진학을 한 20대 초반의 사회 초년생은 군 입대 문제로 많은 고민과 큰 걱정을 하고 있다. 이에 군에 대한 부정적인 인식과 군 생활 적응은 사회가 같이 풀어야 할 문제이다. 따라서 방송사 등 문제 해결을 위해 다각적으로 노력하고 있으나 역부족이다. 실제 군 입대 후 스트레스 및 불안정 심리상태의 장병 비중이 높다. 따라서 본 연구는 군 생활에서 일상적인 방법을 통해 스트레스, 불안감을 감소시키고, 집중력을 향상 시키고자 실행하였다. 주의 집중력 증가 및 스트레스, 불안감의 변화를 측정하기 위해 SMR파 대역의 주파수를 직접 노출시킨 실험군과 그렇지 않은 대조군으로 실험을 진행하였다. 실험군과 대조군대한 대응표본 t-검정 결과는 신뢰수준 95%에서 t=2.487, p=0.042로 유의차가 인정되었다. 즉, 가상사격영상에서 특정 주파수를 제시한 실험군의 피실험자들이 스트레스 및 불안정 심리의 완화효과가 발생하였다. 본 실험의 결과를 활용하면 젊은 장병들의 군 생활 적응에 효과가 높은 것으로 사료된다. 추후 연구에서는 심전도와 뇌파의 상관관계의 확인이 필요하다.

In this study, a process is developed for 3D printing with alumina (Al2O3). First, a photocurable slurry made from nanoparticle Al2O3 powder is mixed with hexanediol diacrylate binder and phenylbis(2,4,6- trimethylbenzoyl) phosphine oxide photoinitiator. The optimum solid content of Al2O3 is determined by measuring the rheological properties of the slurry. Then, green bodies of Al2O3 with different photoinitiator contents and UV exposure times are fabricated with a digital light processing (DLP) 3D printer. The dimensional accuracy of the printed Al2O3 green bodies and the number of defects are evaluated by carefully measuring the samples and imaging them with a scanning electron microscope. The optimum photoinitiator content and exposure time are 0.5 wt% and 0.8 s, respectively. These results show that Al2O3 products of various sizes and shapes can be fabricated by DLP 3D printing.

In this study, we measured the concentration of total volatile organic compounds (TVOCs) in four different seasons from 2016 to 2017 in order to determine seasonal variation of indoor air quality in relation to public transportation modes (subways, trains, and express buses). The measurement was carried out both during rush hour when traffic was congested as well as during non-rush hour when traffic was not congested. Effects by season, degree of congestion, and characteristics of public transportation were analyzed on the basis of 295 items of data during the periods of congestion and 295 items of data during the periods of non-congestion. The average TVOCs concentration in winter was the highest with 226.4 μg/m 3 . The average TVOCs concentration on an express bus was the highest with a seasonal average of 142.3 μg/m 3 . The TVOCs concentration in the period of congested traffic was higher than in the period of non-congested traffic for all public transportation modes. For the average TVOCs concentration by season and transportation, there was no data that exceeded the guidelines regarding maintaining indoor air quality. However, 2.5% of all sample measured data (TVOCs) exceeded the guidelines regarding maintaining indoor air quality. Therefore, the continuous monitoring of public transport vehicles is required.

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).

원전 해체 공정 중 절단 및 용융작업에서 발생되는 방사성 에어로졸은 작업종사자의 호흡을 통해 내부 피폭을 유발하게 된다. 이에 따라 해체 중 방사성 에어로졸로 인한 작업종사자의 내부피폭 평가가 필요한 실정이다. 정확한 내부피폭평가를 위해서는 작업종사자의 작업환경 실측값이 필요하지만 실측에 어려움이 있을 시에는 국제방사선방호위원회(ICRP)에서 제시하는 섭취량 분율 및 입자 크기 등의 권고 값을 통해 내부피폭선량을 추정할 수 있다. 본 논문에서는 입자 크기의 선정은 ICRP에서 권고하는 작업종사자의 고려 입자 크기인 5 μm을 적용하였다. 발생량의 경우, 불가리아의 Kozloduy 부지 내의 용융시설에서 발생 된 에어로졸의 포집량 데이터를 이용하여 섭취량을 산정하였다. 또한 이를 이용해 작업종사자의 체내 및 배설물에서의 방사능 수치를 계산하고 BiDAS 전산코드를 통해 내부피폭 평가를 수행하였다. Type M이 0.0341 mSv, Type S가 0.0909 mSv로 두 흡수 형태 각각 국내 연간 선량 한도의 0.17%, 0.45% 수준을 나타내었다.

This study aimed to identify specific psychological and brain activation responses relating to the processing of negative emotions in patients with alcohol dependency. The authors hypothesized that patients with alcohol dependency would demonstrate the abnormal functioning of brain regions involved in negative emotions. Eleven male patients diagnosed with alcohol dependence in an inpatient alcohol treatment facility and 13 social drinkers with similar demographics were scanned using functional magnetic resonance imaging (fMRI) as they viewed film clips that evoked negative emotions. During exposure to negative emotional stimuli, the control group evinced significantly greater activity in the right anterior cingulate cortex (ACC) in comparison to patients with alcohol dependency. Correlation analyses demonstrated a negative association in the relationship between beta values from the right ACC and amygdala in participants classified in the control group. No statistically significant relationship was observed for blood oxygenation level-dependent (BOLD) changes between the two regions in the patient group during the elicitation of negative emotions. On the other hand, patients exhibited a greater activation of the amygdala as negative emotions were induced. These results suggest that alcoholism presents pathophysiology of brain activation that is distinct from the responses of healthy individuals functioning as controls.

Phthalate is an endocrine disruptor that interferes with homeostasis and developmental regulation. It is highly toxic to the environment and is associated with various diseases of the human body. Using biological samples from 140 adult subjects, to evaluate the influencing factors which are related to contaminant concentration levels, we used correlation analysis and multiple regression analysis. Lastly, in order to analyze the health effects related to exposure to phthalates, we conducted a risk assessment by estimating acceptable daily intake exposure according to the influential factors. When we compared the concentration level according to influential factors, in general, the subjects who had engaged in home remodeling work had higher urinary phthalate metabolite concentrations levels than the subjects who had not engaged in home remodeling work. We can confirm statistically significant differences in DBP metabolites. In addition, we can confirm the concentration appeared higher in the categories such as using air freshener, sofa and foods. Through conducting a risk assessment of DEHP, BBzP, DiBP, and DnBP by using data on phthalate metabolite concentration in urine, it was found that the average concentration of all metabolites did not exceed TDI.

환율의 변동은 기업가치에 영향을 줄 수 있다. 기업이 타인자본을 사용하지 않는 다면 주가를 기준으로 추정한 환노출은 자기자본 가치의 변화만을 반영한다. 그러나 기업이 타인자본을 사용하는 경우라면 환노출에는 부채의 영향이 반영되어 부채를 사용하지 않는 경우에 비해 환노출이 확대 또는 축소되어 나타날 수 있다. 이 연구에서는 기업의 부채사용과 환노출 간의 관계를 분석한다. 부채의 사용이 환노출에 미치는 영향을 분석하기 위해 ‘환노출 의 부채레버리지 효과’ 가설을 설정한다. 분석 결과 환율의 급격한 변동이 있었던 글로벌금융위기를 포함한 기간 (2006년∼2010년)에서는 부채 사용에 따른 환노출 레버리지효과 가설을 지지하는 결과를 확인하였다. 즉, 부채의 의존도가 높은 기업의 경우 환노출이 증가하였다. 그러나 글로벌금융위기 이후 기간(2011년∼2015년)에서는 환노출 레버리지효과를 지지할 수 있는 결과가 나타나지 않았다. 이 연구의 분석 결과는 금융위기와 같이 환율이 급변하는 기간에는 부채를 많이 사용하는 기업의 경우 환노출의 급격한 증가 가능성을 고려해야 함을 시사한다.

Bisphenol A (BPA) is a common industrial chemical that has been used extensively to make certain plastics and resins since the 1960s. As a potential endocrine disruptors, BPA has been investigated for its impact on fertility/reproduction in animals and humans. However, the molecular mechanisms of BPA action and standard method for detecting BPA-related health hazards are unclear. Considering in-vitro experimental model, we investigated the effects of BPA (0.0001 to 100 μM) exposure on mouse spermatozoa. We revealed that BPA affects several sperm functions by triggering the mitogen-activated protein kinase, phosphatidylinositol 3-kinase, and protein kinase-A (PKA) activity. High doses of this chemical was also likely for the activation of protein tyrosine phosphorylation in a PKA-dependent signaling consequently induced a precocious acrosome reaction. Simultaneously, BPA has been found to decrease the rate of fertilization and early embryonic development. In addition, BPA induced differential protein expression in spermatozoa were responsible for the pathogenesis of many diseases. Considering in vivo experimental model, we deliberate the effects of gestational BPA exposure (TDI, NOAEL, and LOAEL doses) on both ejaculated and capacitated spermatozoa in F1 adult mice. We confirmed that BPA affects several sperm function in F1 male. These effects appeared to be caused by reduced numbers of stage VIII seminiferous epithelial cells in testis and decreased PKA activity and tyrosine phosphorylation (non-capacitated) in spermatozoa. We also noticed that BPA decreased average litter size as well as compromise the rates of cleavage and blastocyst formation. Proteins differentially expressed in both capacitated/ejaculated spermatozoa play a critical role in energy metabolism, stress responses, and fertility, finally predispose to the development of several diseases. On the basis of these results, we suggest that BPA alter spermatozoa function and the proteomic profile, ultimately affecting their fertility potential. Therefore, it is of critical public health significance to reevaluate the levels of BPA exposure that are currently deemed to be acceptable.