• Elastomers and Composites
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• v.44 no.3
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• pp.274-281
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• 2009

Nylon 6 and nylon elastomer were prepared by anionic polymerization route. Nylon elastomers, composed of hard segment of polyamide(PA) and soft segment of polyether(PE), were synthesized by use of TDI terminated polyol with caprolactam. The morphology of the electrospun webs of nylon and nylon elastomers, observed by FE-SEM, showed that the porous electrospun web was composed of nanofibers, whose diameter were in the range of 100 to 180 nm. Their behavior of melting and crystallization and the chemical structure of nylon elastomers were investigated by DSC and ATR FT-IR. Result of tensile testing indicated that nylon has higher tensile strength and lower elongation than nylon elastomers. Atmospheric plasma(APP) with $O_2$ and $N_2$ as reactive gas modified the surface of electrospun nylon and electrospun nylon elastomers allowing them higher hydrophilicity, while APP with $CH_4$ as reactive gas modified the surface of polymers allowing higher hydrophobicity.

• Journal of Environmental Impact Assessment
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• v.20 no.3
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• pp.281-297
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• 2011

The specie composition, stranding crops and the dominant species of phytoplankton were studied in three streams, Namdae-stream, Yeongok-stream and Sacheon-stream from May 2008 to February 2009. The water qualities of the three streams which run into estuary were also examined using phytoplankton indicators. As the result, the phytoplankton appeared 94 taxa in Namdae-stream, 79 taxa in Yeongok-stream and 73 taxa in Sacheon-stream, diatoms appeared the most in phytoplankton. Genus Navicula and Cymbella in diatoms appeared to be over 10 taxa in each stream, N. cryptocephala, N. cryptotenella and N. gregaria, the pollution tolerance taxa, appeared more frequent in the downstream. Due to the separation of each substrate by the rapid water velocity in the upstream, Achnanthes minutissima, a known periphyton, was dominant in upstream site at Namdae and Yeongok-stream. Some construction areas and sites of downstream of Namdae-stream, Yeongok-stream and Sacheon-stream were shown to be polluted because pollution tolerance taxa, such as Cyclotella meneghiniana, Nitzschia palea and Oscillatoria limnetica, were dominant. The total of 20 taxa phytoplankton indicators were found, composed of 16 taxa of Water pollution algae including Oscillatoria limosa, 2 taxa of Clean water algae Meridion circulare and Staurastrum puntulatum, 1 taxa of Toxic algae Microcystis aeruginosa and 1 taxa of Taste and odor algae Fragilaria construens. Water pollution indicators were appeared frequently in polluted sites of biological water quality(DAIpo, TDI) and of sites containing high trophic state index(TSI). Therefore, using the phytoplankton indicators can assess water quality through relation of biological water quality and trophic state index.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.30 no.1
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• pp.118-125
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• 2017

Objectives : The aim of this study was to report the effect of Dangguijakyak-san and acupuncture on postviral olfactory disorder. Methods : Dangguijakyak-san extract granule was administered three times a day. Acupuncture was applied to 11 acupoints(EX-HN3, GV20, GV23 and both side of LI04. LR03, LI20, EX-HN8) for 15 minutes once a week. Results : The score of olfactory threshold test and TDI(Threshold-Discrimination-Identification) score increased by 3 points. The subjective sense of smell was improved for the substances that could not previoulsy be smelled. Conclusions : This study shows the possibility of using Dangguijakyak-san and acupuncture to treat postviral olfactory disorder.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.2
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• pp.139-152
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• 2009

According to the third study on the distribution of chemical substances carried out by the Department of Environment in 2006, there were a total of 900 chemical substances whose respective annual usage amount exceeded 1,000 tons and, among them, 90 substances belonged to the 168 hazardous substances requiring management(53.6%). The work-related illnesses caused by hazardous substances requiring management in Korea between $1992{\sim}2005$ can be classified into four groups depending on the type of the chemical substances. These four groups are 23 organic substances including benzene, 12 metals including lead, 3 acids and bases including hydrogen chloride, and 6 gaseous substances including carbon monoxide. These hazardous substances requiring management were again classified depending on the threshold limit values. The chemicals whose TLV was lower than or equal to 0.005 ppm included 4 organic substances including methylene bisphenyl isocyanate and toluene-2,4-diisocyanate (TDI). The chemicals whose TLV was larger than 51 ppm included 22 organic substances including diethyl ether and 1,2-dichloroethylene. When we classified these hazardous substances requiring management according to the categories of GHS health hazards, we found that isobutyl acetate and magnesium oxide didn't belong to the 13 health hazard categories. Among the substances whose TLV is set and whose annual usage amount is more than 0.1 million ton, we recommended 12 chemical species including 4,4'-Methylenedianiline as new hazardous substances requiring management. All the recommended substances were found to be hazardous when we classified their health hazards.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.43-43
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• 2018

수생태계는 다른 여러 생태계 중에서 가장 위험에 처해있으며, 기후변화로 인한 수온, 수문 수질의 변화는 수생태계와 담수 생물다양성에 가장 큰 영향을 미치는 요인 중 하나이다. 본 연구에서는 생물 생태학적으로 변화하는 세계적인 물 관리 패러다임에 따라 한강유역에서의 미래 수생태계 평가를 수행하였다. 본 연구의 목적은 수생태 건강성 관측자료와 수질자료, SWAT 모형을 이용하여 미래 기후변화에 따른 한강유역의 수생태를 평가하는 것이다. 본 연구에서 선정한 수생태계 건강성 조사자료로 국립환경과학원에서 8년간(2008년~2015년) 봄과 가을 2차례에 걸쳐 모니터링 한 부착돌말류(TDI), 저서형 대형무척추동물(BMI), 어류(FAI)에 대한 수생태 등급자료 및 해당 지점에 대한 수온 및 수질자료를 이용하였다. 수집한 결과를 DB(T-N, $NH_4N$, $NO_3N$, T-P, PO4P)에 대한 수생태 등급의 상관성을 분석하고 수온 수질인자에 따른 수생태 등급을 나타내어 미래 기후변화에 따른 수생태 건강성 평가 및 예측을 실시하고자 하였다. Soil and Water Assessment Tool (SWAT) 모형은 유역의 신뢰성 있는 유역 수문, 수질 모의 및 기후변화 영향평가를 위하여 활용되었다. SWAT 모형을 이용하여 한강유역의 다목적댐(3개), 발전용댐(1개), 다기능보(3개) 운영을 고려하였고, 237개의 표준유역으로 분할한 뒤 수문 및 수질 모의를 수행하였다. 모형의 적용성 평가를 위해 댐 및 보의 유입량, 증발산량, 토양수분, 지하수위, SS, T-N, T-P에 대하여 보정(2005~2009) 및 검증(2010~2015)을 수행하였다. 기후변화에 따른 수문, 수질 및 수생태 평가를 위해 기상청의 HadGEM3-RA RCP 4.5와 8.5 시나리오를 적용하였으며, 기준년(1975-2005)년에 대해 2020s(2010-2039), 2050s(2040-2069), 2080s(2070-2099)의 수생태를 평가하였다.

• Journal of odor and indoor environment
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• v.17 no.4
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• pp.315-321
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• 2018

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.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.320-320
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• 2016

본 연구에서는 자연환경, 수생태환경과 관련된 모니터링자료 및 수문/수질 SWAT(Soil and Water Assessment Tool) 모델링 자료를 이용하여 유역건전성을 평가하기 위한 지수를 개발하고, 한강유역($34,148km^2$)을 대상으로 표준유역단위 유역건전성 평가를 수행하였다. 본 연구에서는 미국 EPA(Environmental Protection Agency)의 유역건전성 분석 사례를 개선하여 우리나라에 유역 특성에 맞는 통합 유역건전성 평가지수를 개발하였다. 본 연구에서 분석하고자 하는 유역건전성은 유역이 본래 가지고 있는 자연적인 건전성을 평가하고자 하는 것으로, 평가를 위한 지표로 자연토지피복, 하천환경, 수문, 수질, 서식지, 수생태 관련 요소를 각각 선정하였다. 자연토지피복 및 하천, 서식지 유역건전성 평가를 위해서 DEM, 토지이용도, 하천도, 저수지, 습지자료를 이용하였고, 수생태 유역건전성 평가를 위해서는 6년간(2008년~2013년) 모니터링 된 TDI, BMI, FAI 자료로 이용하였다. 수문/수질 유역건전성 평가를 위해서는 SWAT 모형의 장기모의 결과를 활용하였으며, 30년간(1985년-2014년) 모의된 강수량, 총유출, 지표유출, 침투, 토양수분, 중간유출, 침루, 지하수 충진, 기저유출, Sediment, T-N, T-P 결과를 이용하였다. 각 평가지표로부터 표준유역별 sub-index를 도출하였으며, 6가지 sub-index를 이용하여 통합 유역건전성 지수를 산정하였다. 산정된 지수는 0부터 1까지의 값으로 나타나며, 1에 가까울수록 유역건전성이 좋은 유역을 의미한다. 연구결과 한강유역의 통합 유역건전성은 상류에서 하류로 갈수록 건전성이 안 좋아지는 것으로 분석되었으며, 특정 표준유역에 대하여 자연환경, 수문, 수질, 수생태환경 각각의 유역건전성을 평가할 수 있었다.

• Journal of Chest Surgery
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• v.54 no.1
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• pp.59-64
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• 2021

Background: Diaphragmatic injuries following blunt or penetrating thoraco-abdominal trauma are rare, but can be life-threatening. Rib fractures are the most common associated injury in patients with a traumatic diaphragmatic injury (TDI). We hypothesized that the pattern of rib fracture injuries could dictate the likelihood of acute TDIs. Methods: A retrospective study was carried out between April 2014 and October 2018 to analyze patients with TDIs and rib fractures at a major trauma center in London, United Kingdom. Results: Over the study period, 1,560 patients had rib fractures, of whom 14 had associated diaphragmatic injuries. Left-sided diaphragmatic injuries were found in 8 patients (57%). A significant proportion of the rib fractures were located posterolaterally (44.9%). The highest frequency of fractures was found in ribs 5-10, which accounted for 74% of all the fractures. Ten patients underwent surgery, of whom 7 were diagnosed with a diaphragmatic injury intraoperatively after video-assisted thoracoscopic surgery assessment of the pleural cavity. Two patients died due to severe injuries of other organs and the remaining 2 patients were managed conservatively. Conclusion: Our series of patients demonstrates a relationship between significant rib fractures and diaphragmatic injuries in trauma patients, and the diagnostic difficulties in identifying the condition. We found that the location of the rib fractures and the pattern of injury in patients with TDIs were much lower and posterolateral in the chest wall without a preference for laterality. We suggest using a thoracoscope in patients undergoing chest wall surgery post-trauma to aid in diagnosing this condition.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.630-634
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• 2020

We developed a processing recipe to synthesize flexible polyurethane foam with a pore size of 335 ± 107 ㎛. The gelling reaction time was varied from 0 to 30 minutes and the physical properties of the foam were evaluated. The gelling reaction where the polypropylene glycol and tolylene 2,4-diisocyanate (TDI) were reacted to form urethane prepolymer, proceeded until a chemical blowing agent, deionized water, was introduced. Fourier transform infrared (FT-IR) spectra showed that the composition of the foam did not change but the foam height reached a peak value when the gelling reaction time was 10 minutes. We found that increasing the gelling time lessened the coalescence and helped the formation of cells. Lastly, the repeatability of polyurethane foam was confirmed by one-way analysis of variance (ANOVA) by synthesizing ten identical polyurethane foams under the same experimental conditions, including the gelling reaction time. Overall, the new time parameter in-between the gelling and blowing reactions will give extra stability in manufacturing identical polyurethane foams and can be applied to various polyurethane foam processes.

• Korean Journal of Pharmacognosy
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• v.51 no.4
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• pp.270-277
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• 2020

This study analyzed mycotoxins, aflatoxin B1, B2, G1, G2, fumonisin B1, B2, ochratoxin A and zearalenone, using LC-MS/MS and conducted risk assessment on 54 samples of seeds distributed in SeoulYangnyeongsi and the management status of extramural herbal dispensary facility. The matched calibration showed a good linearity as observed in 6 concentration levels(r2>0.999) as a result of method validation applied with Arecae semen. Limits of detection(LOD) and quantification(LOQ) were in the range of 0.02-0.11 ㎍/kg and 0.08-0.34 ㎍/kg, respectively. Recoveries also estimated, ranging from 65.1-99.7% with relative standard deviation(RSD) 0.5-6.3%. As a result of the method on 54 samples, mycotoxins were detected in 16 samples. Among them, two Thujae semen showed a degree of concentration that exceeded the aflatoxin specification. In the risk assessment, the human exposure safety standard values were calculated as ADI(Acceptable Daily Intake) for aflatoxin B1, fumonisin and zearalenone. Ochratoxin A was calculated as PTWI(Provisional Tolerable Weekly Intake). The MOE(Margine of Exposure) of aflatoxin B1 was in the range of 40.36-3536.88. And no items exceeded 100% in %TDI(Tolerable Daily Intake) and %TWI(Tolerable Weekly Intake) of fumonisin, zearalenone and ochratoxin A.