• 한국산업보건학회지
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• 제21권3호
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• pp.139-145
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• 2011

Objectives: This investigation is purposed to evaluate the airborne asbestos concentrations in the public buildings having asbestos containing materials(ACMs) in Seoul. Methods: The Seoul Metropolitan Government carried out an asbestos survey to the city-owned public buildings to identify the level of risk exposure, classified into low, moderate and high risk. To evaluate the airborne concentration of asbestos, 11 sampling sites in ten buildings based on the survey were selected. The air samples from the eleven sites were analyzed by Phase Contrast Microscopy(PCM) and Transmission Electron Microscopy (TEM), and compared the analytical results from the both. Results: 1. The airborne fiber concentrations by PCM were less than the detection limit($7f/mm^2$) in 9(82%) out of 11 sampling sites. The highest concentration was 0.0043 f/cc, but it was below the guideline value for indoor air quality(0.01 f/cc), proposed by the Ministry of Environment, Korea. 2. In two sampling sites, having moderate risk level, the chrysotile was identified and showed it's concentrations of 0.0102 s/cc and 0.0058 s/cc, less than $5{\mu}m$ lengths. 3. The ACMs identified in the two sampling sites were a packing material(65% of chrysotile) in mechanical area and a thermal system insulation(5% of chrysotile) in a boiler room. Having more possibility of asbestos emission in the mechanical area, it would be required to set up and carry out the asbestos management plan. Conclusions: Based on the result of this study, the airborne asbestos concentrations in the public buildings with ACMs were generally lower than the guideline value for indoor air quality. There are widespread concerns about the possible health risk resulting from the presence of airborne asbestos fibers in the public buildings. Most of the previous studies about airborne asbestos analysis in Korea were performed based on PCM method that asbestos and non-asbestos fibers are counted together. In the public and commercial buildings, having ACMs, it is suggested that the asbestos be analyzed by TEM method to identify asbestos due to concerns about asbestos exposure to workers and unspecified people.

• 한국대기환경학회지
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• 제24권3호
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• pp.346-356
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• 2008

Asbestos is the name of a group of minerals with long and thin fibers that originate naturally in the environment. Asbestos mainly affects lungs and the membrane that surrounds the lungs. In general, PCM (phase contrast microscopy) and PLM (polarized light microscopy) have been used to analyze asbestos fibers. However, these methods have often problems to over-estimate number concentration when counting real asbestos fibers. Moreover, there are many difficulties when separating and identifying various asbestos and non-asbestos fibers. In order to determine quantitative information on fibrous particles, source profiles for asbestos and non-asbestos fibers must be initially developed on the basis of their chemical compositions and physical parameters. In our study, a SEM/EDX was used to develop source profiles from known asbestos samples as reference samples. We could make the source profile matrix consisting of 6 types of asbestos fibers and 2 types of non-asbestos fibers by analyzing 380 fibers. Based on these profiles, a rule building expert system was developed by using the visual basic application (VBA). Various fibers were successfully classified by 2 simple rules in the EXCEL environment based on several visual steps such as inserting data, viewing results, and saving results. For a case study to test the expert system, samples from a construction materials and from various indoor environments such as a residental area, a preschool classroom, and an underground store were collected and analyzed. As a result of the survey, a total of 76 individual test fiber particles was well classified into 5 different types of particle classes; 9.3% of chrysotile, 15.4% of amosite, 0.8 of crocidolite, 4.2% of tremolite, 5.8% glass fiber, 21.1% of other fibers, and 43.5% of unknown fibers in terms of number concentration. Even though unknown portion was high, it will be decreased markedly when expanding fiber source profiles.

• Applied Biological Chemistry
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• 제38권5호
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• pp.435-439
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• 1995

바이러스 살충제의 개발을 위한 기초 자료로서 Hyphantria cunea nuclear polyhedrosis virus(HcNPV)의 일부 특성과 병원성을 조사하였다. HcNPV는 Spodoptera frugiperda (Sf)세포의 핵에서 복제 되었으며, 바이러스를 감염 시켰을 경우 감염 24시간 후에 prepolyhedra 형성이 관찰 되었고, 감염 48시간 후에는 성숙된 많은 polyhedra가 전체세포에서 관찰 되었으며, 감염 72시간 후에는 polyhedra가 세포밖으로 방출 되었다. 또한 세포는 부유 배양에서 잘 성장 하였으며, 바이러스에 감염되기 전의 세포 배양액은 pH가 6.35이었으나 이주 점차 증가하여 감염 120시간 후에는 pH가 6.77이었다. Polyhedra inclusion body(PIB)를 설탕 밀도구배 원심 분리한 결과 $50{\sim}55%$ 부근에서 벤드가 형성 되었고, polyhedra는 도립 현미경과 전자 현미경하에서 관찰한 결과 대부분 4변형의 6면체(tetragonal hexahedron) 이었고, PIB의 크기는 평균 $2.5{\mu}m$이었다. 또한 감염 48시간 후에 polyhedra 속에는 다발을 형성한 비리온이 봉입 되어 있었다. 흰불나방 유충에대한 병원성 시험에서는 4령에서 보다는 2령과 3령의 유충에서 치사율이 높았고, $1.5{\times}10^{9}{\sim}l.5{\times}10^{7}PIB/ml$로 섭식시킨 구룹에서는 2령과 3령 유충에서 90% 이상의 치사율을 나타 내었다.

• 대한환경공학회지
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• 제27권7호
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• pp.771-776
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• 2005

최근 항균 성능이 뛰어나면서도 인체에 유해하지 않은 나노 사이즈 은 입자를 이용한 항균 제품 개발 및 연구가 활발히 이루어지고 있음에 따라, 나노 사이즈의 은 입자를 보다 쉬운 방법으로 균일하게 제조하고, 그 특성을 평가하는데 많은 관심이 집중되고 있다. 본 연구에서는 은 이온의 광환원을 통해 나노 은 입자를 $15{\sim}20\;nm$ 크기로 균일하게 제조한 뒤, 나노 은 입자의 농도, pH, 온도가 변화함에 따른 항균 특성을 살펴보고 이를 정량적으로 평가, 은 이온의 항균 특성과 비교하였다. 또한 주사 전자 현미경과 투과 전자 현미경을 통하여 나노 은 입자의 미생물 불활성화 특성을 은 이온의 미생물 불활성화 특성과 비교하였다. 주요 결과로는 나노 은 입자의 항균 효과는 동일한 은 농도를 기준으로 하였을 때 은 이온의 항균 효과에 비하여 약 20배 정도 적은 것을 알 수 있었다. 또한 나노 은 입자의 농도, 온도가 높을수록 항균 성능은 향상됨을 알 수 있었으며 이는 은 이온의 실험 결과와 일치한다. 그러나 나노 은 입자의 항균 성능은 높은 pH에서 향상된 반면, 은 이온의 경우 pH 변화에 따른 항균 성능 변화가 관찰되지 않았다. 나노 은 입자와 은 이온에 의해 불활성화된 미생물을 주사 전자 현미경과 투과 전자 현미경으로 관찰한 결과, 나노 은 입자는 미생물 세포막을 크게 손상시키는 반면, 은 이온은 그렇지 않았다. 은 이온의 경우 은 이온이 미생물 안으로 흡수되어 세포질막을 손상시켜 미생물을 불활성화 시키는 것으로 알 수 있었다.

• 대한화장품학회지
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• 제48권1호
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• pp.55-64
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• 2022

Cleansing foam이라 불리는 지방산 칼륨 cream soap은 crystal gel 구조로 이루어져 있어 유화계와는 달리 전단응력에 약하며 고온의 보관조건에서 쉽게 분리되는 특성을 보여준다. Crystal gel 구조는 지방산의 종류 및 비율, 중화도, polyol의 종류와 사용량에 따라 크게 영향을 받는다. Crystal gel 구조에 미치는 이들의 영향을 조사하기 위해 water/potassium hydroxide (KOH)/fatty acid ternary system에서 실험을 실시하였다. Differential scanning calorimeter (DSC) 측정 결과 myristic acid (MA) : stearic acid (SA) = 3 : 1 비율에서 공융점(eutectic point)를 갖고 이 혼합비가 가장 안전한 삼성분계(ternary system)를 만든다는 것을 발견했다. 점도 측정과 편광현미경 (POM) 관찰 결과 중화도는 75% 부근이 최적이라고 판단된다. 삼성분계의 melting point (T_m)이 보관온도보다 높을 때, 그리고 crystal phase가 lamellar gel phase로 상 전이가 일어날 때 안정하나 지방산 함량의 증가는 안정성에 거의 영향을 미치지 않는다. 삼성분계에 polyol의 첨가는 T_m을 변화시키고 상전이를 일으키는데 중요한 역할을 한다. 클렌징폼의 구조는 저온 주사전자현미경 (Cryo-SEM), 소각 및 광각 X-선 산란 (SAXS, WAXS) 분석으로 규명하였다. Butylene glycol (BG), propylene glycol (PG), dipropylene glycol (DPG)은 T_m을 낮추어주며 lamellar gel phase 형성을 어렵게 하는 반면 glycerin, PEG-400, sorbitol은 T_m을 상승시키고 lamellar gel phase 형성을 용이하게 하며 안정한 삼성분계를 만든다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권9호
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• pp.4983-4988
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• 2013

Objectives: To establish a taxol-resistant cell line of human ovarian carcinoma (A2780/Taxol) and investigate its biological features. Methods: The drug-resistant cell line (A2780/Taxol) was established by continuous stepwise selection with increasing concentrations of Taxol. Cell morphology was assessed by microscopy and growth curves were generated with in vitro and in vivo tumor xenograft models. With rhodamine123 (Rh123) assays, cell cycle distribution and the apoptotic rate were analyzed by flow cytometry (FCM). Drug resistance-related and signal associated proteins, including P-gp, MRPs, caveolin-1, PKC-${\alpha}$, Akt, ERK1/2, were detected by Western blotting. Results: A2780/Taxol cells were established with stable resistance to taxol. The drug resistance index (RI) was 430.7. Cross-resistance to other drugs was also shown, but there was no significant change to radioresistance. Compared with parental cells, A2780/Taxol cells were significantly heteromorphous, with a significant delay in population doubling time and reduced uptake of Rh123 (p<0.01). In vivo, tumor take by A2780 cells was 80%, and tumor volume increased gradually. In contrast, with A2780/Taxol cells in xenograft models there was no tumor development. FCM analysis revealed that A2780/Taxol cells had a higher percentage of G0/G1 and lower S phase, but no changes of G2 phase and the apoptosis rate. Expression of P-gp, MRP1, MRP2, BCRP, LRP, caveolin-1, PKC-${\alpha}$, Phospho-ERK1/2 and Phospho-JNK protein was significantly up-regulated, while Akt and p38 MARK protein expression was not changed in A2780/Taxol cells. Conclusion: The A2780/Taxol cell line is an ideal model to investigate the mechanism of muti-drug resistance related to overexpression of drug-resistance associated proteins and activation of the PKC-${\alpha}/ERK$ (JNK) signaling pathway.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.1-18
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• 1996

There are many advantages when using IIF and DNA probe methods over anaerobic culture method in that they are time-and effort-saving, more precise and more sensitive. Furthermore, in IIF and DNA probe methods, the detection is possible only with small amount of bacteria, the quantitative analysis is possible, and the cell viability is not necessary. The purpose of this study is to observe the incidence of P.endodontalis by carrying out anaerobic culture, IIF and colony lift using DNA probe method respectively, and to compare these 3 methods in terms of effectiveness and sensitivity in order to identify the most effective detection method. 30 teeth with at least one clinical symptoms, with single canal, and with pulp necrosis were sampled. For sampling bacteria, access cavity was prepared after disinfecting tooth and its surroundings. Then the paper point was inserted up to the periapical area, leave there for a while, and finally it was placed into PRAS Ringer's sol. and PBS sol. In anaerobic culture method, P.endodontalis was identified by biochemical tests after subculturing black and brown colonies which were produced after 7 days of incubation on BAP and Brucella BAP in anaerobic chamber. To identify P.endodontalis in IIF method, species-specific polyclonal rabbit-antisera of P.endodontalis(ATCC 35406) was reacted with sampled PBS sol. dispensed onto glass slide, and then P.endodontalis was examined by phase contrast microscopy after incubating with Goat anti-rabbit lgG conjugated to Fluorescein isothiocyanate. For colony lift using DNA probe method, membranes were laid over colonies on the surface of BAP and were hybridized with cloned DNA probe of P.endodontalis. The existence of P.endodontalis was then identified by the methods of chemiluminescent detection and color metric detection. Black colony was found in 11 teeth out of 30 teeth and P.endodontalis was detected in 6 teeth (20 %) by anaerobic culture method, 16 teeth (53 %) by IIF method, and 7 teeth (23 %) by DNA probe method. IIF method is significantly better in detecting P.endodontalis than DNA probe method and anaerobic culture method. There was no significant differences between DNA probe method and anaerobic culture method. There was significant correlation between the formation of black colony and the existence of P.endodontalis. The probability of detecting P.endodontalis when black colony being present is 2.89 times higher than when not being present. There was significant relationship between the foul odor of clinical symptoms and P.endodontalis. The sensitivity of existing P.endodontalis when foul odor being present was 93.75 %, while the specificity of not existing P.endodontalis when foul odor not being present was 28.57 %. These results suggested that the probes of P.endodontalis will be used to decide the method and prognosis in endodontic treatments.

• Archives of Plastic Surgery
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• 제32권2호
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• pp.143-148
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• 2005

Chemotactic migration of bone forming cell, osteoblast, is an important event during bone formation, bone remodeling, and fracture healing. Migration of cells is mediated by adhesion receptors, such as integrins, that link the cell to extracellular matrix ligands, type I collagen, fibronectin, laminin and depend on interaction between integrin and extracellular ligand. Our study was designed to investigate the effect of extracellular matrix like fibronectin, laminin, type I collagen on migration of osteoblast. Migration distance and speed of MC3T3-E1 cell on extracellular matrix-coated glass were measured for 24 hours using 0.01% type I collagen, 0.01% fibronectin, 100 microliter/ml laminin. The migration distance and speed of MC3T3-E1 cell was compared using a video-microscopy system. To determine migration speed, cells were viewed with a 4 phase- contrast lens and video recorded. Images were captured using a color CCD camera and saved in 8-bit full-color mode. The migration distance on 0.01% type I collagen or 0.01% fibronectin was longer than that on $100{\mu}l/ml$ laminin-coated glass. The migration speed on fibronectin-coated glass was 68 micrometer/hour which was fastest. The migration speed on type I collagen-coated glass was similar with that on fibronectin-coated glass. The latter two migration speeds were faster than that on no-coated glass. On the other hand, the average migration speed on laminin-coated glass was 37micrometer/hour and not different from that of control group. In conclusion, the extracelluar matrix ligands such as type I collagen and fibronectin seem to play an important role in cell migration. The type I collagen or fibronectin coated scaffold is more effective for migration of osteoblast in tissue engineering process.

• 생명과학회지
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• 제20권2호
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• pp.253-259
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• 2010

본 연구는 땅콩나물 추출물이 glutamate가 유도하는 세포독성으로부터 신경세포를 보호하는 효과를 확인하였다. 땅콩나물을 부위별로 전체, 머리, 줄기 부분으로 나누어 methanol로 처리하여 얻어진 각각의 추출물 WME, HME 그리고 SME를 이용하여 glutamate에 의하여 유도된 세포독성에 대한 신경세포보호효과를 관찰하였다. 기지의 신경세포 N18-RE-105 세포주를 이용하여 MTT reduction assay, LDH release assay, 형태학적인 변화 및 apoptosis를 관찰한 결과로부터 HME에서 효율적인 신경세포보호효과를 보였다. 다음으로 HME를 이용하여 hexane, diethyl ether, ethyl acetate, water 층으로 분획하여 신경세포 보호 효과를 확인한 결과, diethyl ether 층에서 가장 높은 활성을 확인할 수 있었다. 그리고 HME의 apoptosis 억제 효과를 확인하기 위하여 flow cytometric analysis를 실시한 결과에서 glutamate 만을 처리하였을 경우 sub-G1기 세포가 58.5%의 확인되었으나 HME를 100 mg/ml 동시 처리하였을 때에는 sub-G1 세포가 9.1%로 감소하여 높은 apoptosis 억제 효과를 확인할 수 있었다. 이상의 결과로부터 땅콩나물 머리 부분 methanol 추출물에는 glutamate에 의한 세포독성으로부터 신경세포를 보호하는 효과가 있다는 것을 알 수 있었다.

• 한국융합학회논문지
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• 제2권1호
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• pp.31-36
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• 2011

이 연구는 치과 기공사의 석면 사용의 문제를 조사 수행하였다. 분석을 위한 샘플은 2010년 12월에서, 2011년 1월까지 대구광역시 10개 치과기공소에서 40개의 샘플링을 개인 샘플러에 의해 샘플 되었고 위상차 현미경으로 분석하였다. 측정결과는 다음과 같다. 1. 10개 치과기공소 40개소의 공기 중 석면의 기하평균농도는 0.0061 f/cc 로서 작업환경기준 및 실내환경기준에 미달하였으나 2개 치과기공소에서 실내환경관리기준을 초과하였다. 2. 가공실과 소환실의 공기 중 석면의 기하평균농도는 가공실이 0.0099 f/cc로 소환실 0.0037 f/cc 보다 높았다. 3. 치과기공소에서 사용 중인 Casting ring liner 종류별 공기 중 석면농도는 산업용석면제품을 사용하는 곳이 0.0159f/cc로 가장 높았고, 다음이 석면함유제품을 사용하는 곳 0.0104 f/cc, 비석면제품을 사용하는 곳 0.0026 f/cc 순으로 나타났다. 치과기공소에서 석면이 함유된 Casting ring liner를 사용하고 작업환경농도 또한 일부 치과기공소에서 실내환경기준을 초과하는 것으로 나타나고 있으므로 석면제품 Casting ring liner를 비석면제품으로 대치(Substitution)하는 대책이 시급히 강구되어야 하고 환기설비를 보완하여 치과기공사들의 건강을 보호할 수 있도록 하여야 하겠다.