• 제목/요약/키워드: repeated exposure

검색결과 245건 처리시간 0.029초

Twenty-Eight-Day Repeated Inhalation Toxicity Study of Nano-Sized Neodymium Oxide in Male Sprague-Dawley Rats

  • Kim, Yong-Soon;Lim, Cheol-Hong;Shin, Seo-Ho;Kim, Jong-Choon
    • Toxicological Research
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    • 제33권3호
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    • pp.239-253
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    • 2017
  • Neodymium is a future-oriented material due to its unique properties, and its use is increasing in various industrial fields worldwide. However, the toxicity caused by repeated exposure to this metal has not been studied in detail thus far. The present study was carried out to investigate the potential inhalation toxicity of nano-sized neodymium oxide ($Nd_2O_3$) following a 28-day repeated inhalation exposure in male Sprague-Dawley rats. Male rats were exposed to nano-sized $Nd_2O_3-containing$ aerosols via a nose-only inhalation system at doses of $0mg/m^3$, $0.5mg/m^3$, $2.5mg/m^3$, and $10mg/m^3$ for 6 hr/day, 5 days/week over a 28-day period, followed by a 28-day recovery period. During the experimental period, clinical signs, body weight, hematologic parameters, serum biochemical parameters, necropsy findings, organ weight, and histopathological findings were examined; neodymium distribution in the major organs and blood, bronchoalveolar lavage fluid (BALF), and oxidative stress in lung tissues were analyzed. Most of the neodymium was found to be deposited in lung tissues, showing a dose-dependent relationship. Infiltration of inflammatory cells and pulmonary alveolar proteinosis (PAP) were the main observations of lung histopathology. Infiltration of inflammatory cells was observed in the $2.5mg/m^3$ and higher dose treatment groups. PAP was observed in all treatment groups accompanied by an increase in lung weight, but was observed to a lesser extent in the $0.5mg/m^3$ treatment group. In BALF analysis, total cell counts, including macrophages and neutrophils, lactate dehydrogenase, albumin, interleukin-6, and tumor necrosis factor-alpha, increased significantly in all treatment groups. After a 4-week recovery period, these changes were generally reversed in the $0.5mg/m^3$ group, but were exacerbated in the $10mg/m^3$ group. The lowest-observed-adverse-effect concentration of nano-sized $Nd_2O_3$ was determined to be $0.5mg/m^3$, and the target organ was determined to be the lung, under the present experimental conditions in male rats.

정기적인 찜질방노출이 청년과 노년 여성의 내한성에 미치는 영향 (The Effects of Regular Jjimjilbang Exposure on Cold Tolerance in Young and Elderly Females)

  • 최정화;송은영;황수경
    • 한국지역사회생활과학회지
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    • 제18권4호
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    • pp.599-607
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    • 2007
  • We analyzed the effects of regular Jjimjilbang (Korean sauna) exposure on the cold tolerance in young and elderly females. Subjects were young (n=7) and elderly (n=7) females who had never had Jjimjilbang exposure experience. The Jjimjil training group was exposured in the Jjimjilbang 19 times per week. Jjimjibang exposure was limited to three times per day. Jjimjil activity was taken freely. To prove the effects of the cold tolerance, subjects were exposed to cold air ($12{\pm}1^{\circ}C,\;60{\pm}10%$RH). In these conditions, subjects were exposed for 30 minutes at which time rectal temperature, skin temperatures, clothing microclimate, energy expenditure, blood pressure and subjective sensation were measured. To prove the effects of the local cold tolerance, vascular hunting reaction was observed measuring the finger skin temperature while the left middle finger tip was immersed in cold water of $0^{\circ}C$ for 30 minutes. The results are as follows. According to repeated Jjimjil exposure, rectal temperature changes, peripheral temperature and energy expenditure were increased gradually in the cold climate chamber. Blood pressure, subjective sensation and vascular hunting reactions did not show any significant difference. In conclusion, regular Jjimjilbang exposure has negative effects on the ability of the body to improve its regulation of temperature especially in cold tolerance.

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석유계총탄화수소의 위해성평가 시 적정 분획 시료수 결정에 대한 고찰 (Study on the Soil Sample Number of Total Petroleum Hydrocarbons Fractionation for Risk Assessment in Contaminated Site)

  • 전인형;김상현;정현용;정부윤;노회정;김현구;남경필
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제24권5호
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    • pp.11-16
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    • 2019
  • In this study, a reliable number of soil samples for TPH fractionation was investigated in order to perform risk assessment. TPH was fractionated into volatile petroleum hydrocarbons (VPH) with three subgroups and extractable petroleum hydrocarbons (EPH) with four subgroups. At the study site, concentrations of each fraction were determined at 18 sampling points, and the 95% upper confidence limit (UCL) value was used as an exposure concentration of each fraction. And then, 5 sampling points were randomly selected out of the 18 points, and an exposure concentration was calculated. This process was repeated 30 times, and the results were compared statistically. Exposure concentrations of EPH obtained from 18 points were 99.9, 339.1, 27.3, and 85.9 mg/kg for aliphatic $C_9-C_{18}$, $C_{19}-C_{36}$, $C_{37}-C_{40}$, and aromatic $C_{11}-C_{22}$, respectively. The corresponding exposure concentrations obtained from 5 points were 139.8, 462.8, 35.1 and 119.4 mg/kg, which were significantly higher than those from 18 points results (p <0.05). Our results suggest that limited number of samples for TPH fractionation may bias estimation of exposure concentration of TPH fractions. Also, it is recommended that more than 30 samples need to be analyzed for TPH fractionation in performing risk assessment.

파라콰트에 의한 피부 손상의 임상적 고찰 (Paraquat Poisoning by Skin Absorption)

  • 양종오;길효욱;이은영;홍세용
    • 대한임상독성학회지
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    • 제2권2호
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    • pp.101-105
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    • 2004
  • Purpose: Paraquat is the most commonly used herbicide in Korea. Exposure to paraquat through the skin has resulted in local irritation or inflammation of varying degree, sometimes severe. The purpose of this study was to review the patients with paraquat poisoning by skin absorption. Methods: We analysed retrospectively the clinical and laboratory findings of 45 patients with paraquat poisoning after dermal exposure, who were admitted to Soonchunhyang University Cheonan Hospital from January 1999 to December 2003. Results: Among 870 cases of paraquat poisoning, 45 cases were exposed to paraquat through the skin. The peak incidence was the fifth decade($40\%$). The clinical symptoms were pain, pruritus, nausea, and vomiting. The major skin lesions were generalized vesicobullae and necrotic erosion in face, scrotum, trunk, upper and lower extremities and etc. All patients were survived after skin contact or inhalation of paraquat. Conclusion: This study illustrates the extreme toxicity of paraquat and demonstrates that lethal quantities of paraquat may be absorbed if repeated exposure to it. Stricter precautions, including the mandatory use of protective clothing, should be recommended whenever this material is used.

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네덜란드의 토양환경정책 (Soil Environmental Policy in Netherlands)

  • 송창수
    • 한국토양환경학회지
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    • 제2권2호
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    • pp.3-8
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    • 1997
  • 본 고에서는 네덜란드에서 시행하고 있는 토양환경정책에 대하여 정리하여 보았다. 네덜란드 토양환경관리목표는 토양의 다기능성의 유지 및 회복에 두고 있다. 네덜란드의 토양법체계는 토양보호법을 중심으로 환경관리법, 건축법 등을 통해 토양환경의 보전을 하고 있으며, 공장지대나 주유소는 토양보호법의 테두리 안에서 별도의 명령을 통해 관리되고 있다. 아울러 정화의 책임에 대하여 오염원인자부담원칙 및 정부부담의 원칙을 취하고 있는데, 1987년 이전에 대해서는 책임을 묻지 않는 방법을 취하고 있다. 정화의 책임순서로는 오염원인자, 소유자, 권리행사자 순으로 되어 있으며, 정화는 오염자 스스로 정화를 하도록 유도하고 그렇지 않을 경우에는 정부가 돈을 투자하여 정화를 행하고 있다. 아울러 건축물을 짓고자 할 경우에는 토양에 관한 조사를 하도록 하고 있으며, 토지를 사고 파는 과정에서는 반드시 토양의 질에 관한 정보를 확인하도록 행하고 있다.

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디지털흉부X선촬영에서 검출기 방식에 따른 최적의 노출조건 (Optimal Exposure Conditions according to Detector Type in Chest Digital Radiography)

  • 이원정
    • 대한안전경영과학회지
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    • 제17권4호
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    • pp.213-221
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    • 2015
  • The aim of this study was to set up the optimal exposure condition according to detector type considering image quality (IQ) with radiation dose in chest digital radiography. We used three detector type such as flat-panel detector (FP) and computed radiography (CR), and charge-coupled device (CCD). Entrance surface dose (ESD) was measured at each exposure condition combined tube voltage with tube current using dosimeter, after attaching on human phantom, it was repeated 3 times. Phantom images were evaluated independently by three chest radiologists after blinding image informations. Standard exposure condition using each institution was 117 kVp-AEC at FP and 117 kVp-8 mAs at CR, and 117 kVp-8 mAs at CCD. Statistical analysis was performed by One way ANOVA (Dunnett T3 test) using SPSS ver. 19.0. In FP, IQ scores were not significant difference between 102 kVp-4 mAs and 117 kVp-AEC (28.4 vs. 31.1, p=1.000), even though ESD was decreased up to 50% ($62.3{\mu}Gy$ vs. $125.1{\mu}Gy$). In CR, ESD was greatly decreased from 117 kVp-8 mAs to 90 kVp-8 mAs without significant difference of IQ score (p=1.000, 24.6 vs. 19.5). In CCD, IQ score of 117 kVp-8 mAs was similar with 109 kVp-8 mAs (29.6 vs. 29.0), with decreasing from $320.8{\mu}Gy$ to $284.7{\mu}Gy$ (about 11%). We conclude that optimal x-ray exposure condition for chest digital radiography is 102 kVp-4 mAs in FP and 90 kVp-8 mAs in CR, and 109 kVp-8 mAs in CCD.

수술실 간호사의 방사선 노출 경험: 현상학적 연구 (Paper Operration room nurses Experience in Using Radiation Suegery: Phenomenological Research)

  • 윤재현
    • 한국산학기술학회논문지
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    • 제21권1호
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    • pp.426-438
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    • 2020
  • 본 연구의 목적은 방사선 노출 경험을 참여자의 관점에서 확인함으로써 수술실 간호사의 방사선 노출 경험에 대한 구성요소를 확인하고 의미구조를 밝히는 데 있다. 연구의 참여자는 일 광역시 종합병원 수술실에서 근무하는 간호사로 수술실 경력이 6개월 이상인 자 9명을 대상으로 하였다. 심층면담으로 자료를 수집하였고, Giorgi(2004)의 현상학적 분석 방법으로 분석하였다. 연구 결과 수술실 간호사의 방사선 노출 경험은 "반복되는 방사선 노출로 질환 발생을 걱정함", "육체적, 정신적으로 소진됨", "방사선 방어를 통해 자기보호를 하고자 노력함", "내적 혼란과 갈등을 느낌", "근무환경 개선을 요구함", "현실을 받아들이고 적응함"의 6개 구성요소로 도출 되었다. 결론으로 이들의 경험은 방사선 노출 수술에 참여하면서 질환 발생을 걱정하고 방사선 피폭과 관련된 신체적, 정신적 소진을 경험하고 갈등을 느끼면서 이직을 고려하기도 하지만 자기보호를 하고자 노력하고 현실을 받아들이고 적응하는 과정을 보였다. 본 연구결과의 바탕으로 방사선 안전 환경조성을 위해서는 조직적 차원에서 체계적으로 구체적인 해결 방법을 모색하는 것이 바람직하다고 볼 수 있다.

홍화 황색소를 사용한 모발염색 (Hair-dyeing by Using Safflower Yellow Colorant)

  • 신윤숙;조아랑;류동일
    • 한국의류학회지
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    • 제33권3호
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    • pp.391-400
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    • 2009
  • The purpose of this study is to investigate the efficacy of safflower yellow colorant as a natural dye for hair coloring. The dyeing properties of safflower yellow colorant on hair were explored to obtain optimum conditions. Also, the effect of mordant was studied in terms of dye uptake, colorfastness, and hair damage to better understand the characteristics of the colorant. Tensile strength measurement and SEM analysis were carried out for investigating hair damage to light exposure and washing. On the basis of obtained results considering possible hair damage, optimum dyeing conditions were set 100%(o.w.h.) colorant concentration, pH 5, $40^{\circ}C$, and 20min. Dye uptake was improved more effectively by repeated dyeing rather than by increasing concentration. Pre-mordanting method improved dye uptake slightly, irrespective of mordant type. The safflower yellow colorant produced Y colors on hair. Cu and Fe mordants improved washing and light fastness slightly. Better strength retention was obtained with the mordanted-dyed hair than the unmordanted-dyed hair after light irradiation for 40 hours and 10 repeated washing. The hair was more damaged by light exposure than by washing. It was concluded that the safflower yellow colorant can be used as a natural semi-permanent hair dye producing Y color without mordanting.

Korean Red Ginseng extract attenuates alcohol-induced addictive responses and cognitive impairments by alleviating neuroinflammation

  • Hee Jin Kim;Min Yeong Lee;Gyu Ri Kim;Hyun Jun Lee;Leandro Val Sayson;Darlene Mae D. Ortiz;Jae Hoon Cheong;Mikyung Kim
    • Journal of Ginseng Research
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    • 제47권4호
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    • pp.583-592
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    • 2023
  • Background: Alcohol is one of the most commonly used psychoactive drugs. Due to its addictive characteristics, many people struggle with the side effects of alcohol. Korean Red Ginseng (KRG) is a traditional herbal medicine that is widely used to treat various health problems. However, the effects and mechanisms of KRG in alcohol-induced responses remain unclear. Therefore, the purpose of this study was to investigate the effects of KRG in alcohol-induced responses. Methods: We investigated two aspects: alcohol-induced addictive responses and spatial working memory impairments. To determine the effects of KRG in alcohol-induced addictive responses, we performed conditioned place preference tests and withdrawal symptom observations. To assess the effects of KRG in alcohol-induced spatial working memory impairment, Y-maze, Barnes maze, and novel object recognition tests were performed using mice after repeated alcohol and KRG exposure. To investigate the potential mechanism of KRG activity, gas chromatography-mass spectrometry and western blot analysis were performed. Results: KRG-treated mice showed dose-dependent restoration of impaired spatial working memory following repeated alcohol exposure. Furthermore, withdrawal symptoms to alcohol were reduced in mice treated with KRG and alcohol. The PKA-CREB signaling pathway was activated after alcohol administration, which was reduced by KRG. However, the levels of inflammatory cytokines were increased by alcohol and decreased by KRG. Conclusion: Taken together, KRG may alleviate alcohol-induced spatial working memory impairments and addictive responses through anti-neuroinflammatory activity rather than through the PKA-CREB signaling pathway.

Whole Spine Scanography의 검사방향에 따른 환자 선량 평가 (Patient Radiation Exposure Dose Evaluation of Whole Spine Scanography Due to Exposure Direction)

  • 김정수;서덕남;권순무;김정민
    • 대한방사선기술학회지:방사선기술과학
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    • 제38권1호
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    • pp.1-6
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    • 2015
  • Whole spine scanography(WSS)는 전신에 X선을 조사하는 검사로 치료기간 동안 빈번한 X선 조사가 이루어지는 검사이다. 일반촬영 분야에서는 많은 X선이 전신에 조사되는 검사이다. 따라서 논문에서는 Auto image pasta기법의 디지털 WSS 검사에서 환자의 검사방향에 따른 유효선량과 장기선량을 전산모사를 통하여 평가하였고, 영상에서 척추의 확대도와 각도의 변화를 평가하였다. 전후면 자세에서의 평균 유효선량은 0.069 mSv였고, 후전면 자세에서 평균 유효선량은 0.0361 mSv로 약 2배의 차이를 보였다. 전후면 자세에서 남성의 평균 유효선량은 0.089 mSv, 여성에 대한 평균 유효선량은 0.431 mSv로 나타났고, 후전면 자세에서 남성의 평균 유효선량은 0.050 mSv, 여성에서는 0.026 mSv로 나타났다. 확대율에서는 후전면 자세에서 전후면 자세에 비해 5%정도 확대 되었으나 각도에는 큰 변화를 보이지 않았다. 따라서 임상 환경에서 동일한 검사조건에서 환자의 자세를 변화시키는 것만으로도 환자의 피폭선량을 감소시킬 수 있음을 확인하였다. 특히 WSS와 같이 치료기간 동안 반복되는 검사에서 환자의 피폭선량 최적화를 위하여 검사 프로토콜의 재정립이 필요함을 확인하였다.