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      • 디젤분진이 체세포에서의 DNA 손상에 미치는 영향

        허찬,김남이,정규혁,문창규,허문영 한국환경독성학회 2004 환경독성보건학회지 Vol.19 No.4

        Diesel exhaust panicle (<25μm, DEP_(2.5)) is known to be probarbly carcinogenie (IARC group 2A) DEP_(2.5) contains organic compounds such as polycyclicatomatic hydrocarbon (PAH), heterocyclic compounds, phenols, and nitroarenes Reactive oxygen species (ROS) are generated by DEP_(2.5) without any biological activation system Therefore, an alternative mechanism by which DEP_(2.5) could be carcinogenic is known by the generation of oxidative DNA damage The aim of this study was to investigate genotoxic effects of DEP_(2.5) using single cell gel electrophoresis In order to evaluate the mechanisms of DEP_(2.5) genotoxicity, the rat microsome mediated and DNA repan enzyme treated comet assays together with routine comet assay were performed DEP_(2.5) was collected from diesel engine bus and dichloiomethane extract was obtained The organic extract of DEP_(2.5) revealed DNA damage itself in NIH/3T3 cells And it showed both oxidative and microsome mediated DNA damages Vitamin C as an model antioxidant reduced DNA damage in endonuclase Ⅲ treated comet assay One of flavonoid, galangin as a CYP[A] inhibitor reduced DNA damage in the presence of S-9 mixture Our results show that DEP_(2.5) ate genotoxic and a great source of oxidative stress, but antioxidants can significantly reduce oxidative DNA damages And DEP_(2.5) may contain indirect mutagens which can be inhibited by CYP inhibitors.

      • KCI등재
      • 다단 원판형 드래그펌프의 배기특성에 관한 실험적 연구

        황영규,허중식,권명근 성균관대학교 기계기술연구소 2001 성균관대학교 논문집 기계기술편 Vol.4 No.1

        In this paper, the pumping performance of the multi-stage(two-stage) disk-type drag pump which works in the pressure range from 4 to 0.003 Torr was studied experimentally, and rotational speed of the pump is 24,000rpm and nitrogen is used as a test gas. An experimental study on pumping characteristics of various multi-stage disk-type drag pump is performance. The inlet pressures are measured for various outlet pressures of teat pump. The maximum compression ratios for nitrogen are 1000(multi-stage disk-type drag pump), 740(helical-type drag pump), 90(BSC disk-type drag pump) and 85(OSC disk-type drag pump), respectively. The ultimate pressure of the multi-stage disk-type drag pump is 3.7×10-5 Torr at 0.003 Torr for outlet pressure. The maximum value of compression ratio is 1000 at 0.6 Torr for outlet pressure.

      • SCIESCOPUSKCI등재
      • KCI등재

        물리학 선량법을 이용한 갑상선암의 개인별 최대안전용량 I-131 치료법 개발과 유용성 평가

        김정철,윤정한,범희승,제갈영종,송호천,민정준,정환정,김성민,허영준,이명호,박영규,정준기 대한핵의학회 2003 핵의학 분자영상 Vol.37 No.2

        목적 : 분화갑상선암 환자에 대한 방사성옥소(I-131) 치료는 재발율과 사망률을 감소시키는 효과적인 치료법이지만, 치료용량을 증가시킴으로써 치료율을 향상시킬 수 있는지에 대해서는 아직 논란이 있다. 본 연구에서는 최대허용선량 치료법의 효용성을 검증하고자 하였다. 대상 및 방법 : 임상적 병기가 제3, 4병기이고, 6개월 이후에 I-131 전신스캔(이하 IWBS)과 혈중 thyroglobulin (이하 Tg), anti-thyroglobulin antibody (이하 ATA), 초음파검사 (이하 US) 및 F-18 FDG PET 등을 통해 치료여부를 확인할 수 있었던 58명(남:여=9:49, 평균연령 50±11세)의 유두상갑상선암 환자를 대상으로 하였다. 이중 11명은 제4병기, 47명은 제3병기였으며, 43명(남:여=4:39), 평균연령 50±11세)은 7.4 GBq 이하의 고식적인 저용량치료법으로 치료하였고, 9.25 GBq 이상의 고용량 치료를 받은 환자는 15명(남:여=5:10, 평균연령 50±12세)으로 고용량군에서 남자가 더 많았으나 연령의 차이는 없었다. 고용량군 환자 모두에서 추적용량의 방사성옥소(평균 77±3 MBq)를 경구 투여한 후 혈중 방사능소실곡선을 통해 최대허용선량(maximum permissible dose, 이하 MPD)을 계산하였으며, 7명에서는 말초혈액림프구의 중기염색체분석법에 의해 생물학적으로 MPD를 계산하였다. 14명에서는 치료용량의 방사성옥소를 투여한 후 혈중 방사능소실곡선을 통해 MPD를 계사하였다. 완전치유(complete response, 이하 CR)는 IWBS에서 병소가 없어지고, 혈중 Tg치가 1 ng/mL 이하로 감소한 경우로 정의하였으며, 부분치유(partial response, 이하 PR)는 IWBS에서 병소가 없어졌더라도 혈중 Tg, ATA치가 높거나, US 또는 PET 검사에서 병소가 남아있는 경우로 정의하였다. 치료후 IWBS에서 병소가 오히려 증가하거나 변함없는 경우는 없었다. 방사성옥소 치료에 의한 부작용은 입원기간 중 타액선이 현저하게 붓고 통증이 있거나, 구토를 심하게 하는 경우, 그리고 퇴원후 1개월째 백혈구수가 20% 이상 감소한 경우로 정의하였다. 결과 : 양 군간에 연속적인 수치변화를 비교하는 경우는 paired t-test를 이용하였으며, 대상군간 치료효과와 부작용의 비교는 chi-square test를 이용하였다. p값 0.05 미만을 통계적으로 유의한 차이로 인정하였다. 고용량군 환자 모두에서 추적용량과 치료용량의 방사성옥소 투여 후 혈액의 피폭선량은 각각 0.012±0.3 Gy, 1.66±25 Gy였으며, 방사성옥소 투여 후 혈액에 전달되는 피폭선량은 추적용량보다 치료용량에서 더 많았고 (1.21: 166 rad, p<0.001), 방사성옥소 1 mCi당 혈액에 전달되는 피폭선량은 차이가 없었다(0.58±0.1 vs. 0.56±0.1 rad/37 MBq, p=0.34). 추적용량 방사성옥소 투여 후 구한 MPD는 평균 13.3±1.9 GBq (9.7 ~ 16 GBq) 이였고, 치료용량 방사성옥소 투여 후 구한 MPD는 평균 13.8±2.1 GBq (10.4 ~ 16.3 GBq)로 유의한 차이가 없었으며 (p=0.20), 두 수치간에는 유의한 상관 관계가 있었다(r=0.8, p<0.0001). 7명의 환자에서 말초혈액림프구 중기염색체 분석법으로 MPD를 측정하였는데 혈액의 피폭선량은 1.78±0.03 G였으며, 같은 환자에서 혈중 방사능소실곡선으로부터 구한 피폭선량은 1.54±0.03 G로 유의하게 낮았으나 (p=0.01), 두 측정치 간에는 유의한 상관관계(r=0.86, p=0.01)가 있었다. 저용량 치료군 43명 중 22명(51.2%)에서 완전치유를 보였고 21명(48.8%)에서는 부분치유를 보인 반면 고용량 치료군 15명 중 12명(80%)에서 완전치유를 보였고 3명(20%)에서만 부분치유를 보여 고용량 치료군에서 유의하게 높은 완전치유를 얻을 수 있었다(p=0.05). 한편 부작용 발생빈도는 저용량 치료군 43명 중 13(30.2%), 고용량 치료군 15명 중 6명(40%)로 양군간에 유의한 차이가 없었다(p=0.46). 임상적인 병기, 연령 및 성별에 따라서는 치유의 차이가 없었다(p>0.05). 결론 : 혈중소실곡선으로부터 MPD를 결정하고 이를 토대로 환자 개개인별로 적절한 선량을 선택하여 치료하는 방법은 부작용을 최소화하면서도 치료효과를 높일 수 있는 매우 유용한 치료법이며, 고위험군 분화갑상선 암 환자에게 가장 적절한 치료법이라고 사료되었다. Purpose: Radioiodine (1-131) therapy is an effective modality to reduce both recurrence and mortality rates in differentiated thyroid cancer. Whether higher doses shows higher therapeutic responses was still debatable. The purpose of this study was to validate curve-fitting (CF) method measuring maximum permissible dose (MPD) by a biological dosimetry using metaphase analysis of peripheral blood lymphocytes. Materials and Methods: Therapeutic effects of MPD was evaluated in 58 patients (49 females and 9 males, mean age 50±11 years) of papillary thyroid cancer. Among them 43 patients were treated with ≤7.4 GBq, while 15 patients with ≥9.25 GBq. The former was defined as low-dose group, and the latter high-dose group. Therapeutic response was defined as complete response when complete disappearance of lesions on follow-up 1-131 scan and undetectable serum thyroglobulin levels were found. Statistical comparison between groups were done using chi-square test. P value less than 0.05 was regarded as statistically significant. Results: MPD measured by CF method using tracer and therapeutic doses were 13.3±1.9 and 13.8±2.1 GBq, respectively (p=0.20). They showed a significant correlation (r=0.8, p<0.0001). Exposed doses to blood measured by CF and biological methods were 1.54±0.03 and 1.78±0.03 Gy (p=0.01). They also showed a significant correlation (r=0.86, p=0.01). High-does group showed a significantly higher rate of complete response (12/15, 80%) as compared to the low-dose group (22/43, 51.2%) (p=0.05). While occurrence of side effects was not different between two groups (40% vs. 30.2%, p=0.46). Conclusion: Measurement of MPD using CF method is reliable, and the high-dose 1-131 therapy using MPD gains significantly higher therapeutic effects as compared with low-dose therapy.

      • KCI등재

        정선지역 철광산에 분포하는 암석의 역학적 특성

        김종우,박찬,김주환,허석,김동규,이동길,조영도,박삼규,Kim, Jong-Woo,Park, Chan,Kim, Ju-Hwan,Heo, Seok,Kim, Dong-Kyu,Lee, Dong-Kil,Jo, Young-Do,Park, Sam-Gyu 한국암반공학회 2015 터널과지하공간 Vol.25 No.3

        본 연구에서는 최근 재개발되고 있는 정선지역의 철광산에서 현장 초기지압 시험과 수많은 암석 실내시험을 실시하였다. 본 광산의 측압계수는 심도가 깊어질수록 작아지는 경향을 보였으며 평균값은 1.10으로 나타났다. 본 광산에 주로 분포하는 네 가지 암종인 백운암, 규장암, 화강암, 철광석에 대한 실내시험을 통해 암석의 단위중량, 공극률, 흡수율, 탄성파속도, 일축압축강도, 영률, 포와송비, 인장강도, 쇼어경도, 내부마찰각, 점착력 등의 각종 역학적 특성을 조사하였다. 실내시험 결과의 통계분석을 통해 암종별 물성을 비교하였고 물성 상호간의 관련성을 검토하였는데, 철광석보다는 규장암이나 화강암의 강도특성이 더 컸으며 암석 물성 간의 일반적인 상관관계와는 반대되는 현상도 발견되었다. 또한 Mohr-Coulomb 파괴조건과 Hoek-Brown 파괴조건을 적용하여 네 가지 암석의 파괴조건을 해석하였다. In this study, both in-situ stress measurements and a lot of laboratory rock tests were conducted at a metal mine in Jeongseon, Korea. The stress ratio obtained from in-situ stress measurements showed a tendency to decrease according to depth below surface and its average value was 1.10. The mechanical properties such as unit weight, absorption ratio, porosity, elastic wave velocity, uniaxial compressive strength, Young's modulus, Poisson's ratio, tensile strength, shore hardness, friction angle and cohesion were investigated for the four different rocks mainly distributed at a studied mine, which were dolomite, felsite, granite and magnetite. The mechanical properties of the four different rocks were compared by means of statistical analyses, whereupon the felsite and the granite turned out to have more strength characteristics than the magnetite. The correlation of mechanical properties was also investigated, whereupon a few results against the general correlation were found out. The failure criteria of the four different rocks were finally discussed by means of both Mohr-Coulomb criterion and Hoek-Brown criterion.

      • KCI등재
      • SCISCIESCOPUS

        Downregulation of APE1/Ref-1 Is Involved in the Senescence of Mesenchymal Stem Cells

        Heo, Jun-Young,Jing, Kaipeng,Song, Kyoung-Sub,Seo, Kang-Sik,Park, Ji-Hoon,Kim, Jong-Seok,Jung, Yeon-Joo,Hur, Gang-Min,Jo, Deog-Yeon,Kweon, Gi-Ryang,Yoon, Wan-Hee,Lim, Kyu,Hwang, Byung-Doo,Jeon, Byeong Wiley (John WileySons) 2009 Stem Cells Vol.27 No.6

        <P>The senescence of human mesenchymal stem cells (hMSCs) causes disruption of tissue and organ maintenance, and is thus an obstacle to stem cell-based therapies for disease. Although some researchers have studied changes in the characteristics of hMSCs (decreases in differentiation ability and self-renewal), comparing young and old ages, the mechanisms of stem cell senescence have not yet been defined. In this study, we developed a growth curve for human bone marrow derived MSCs (hBMSCs) which changes into a hyperbolic state after passage number 7. Senescence associated beta-galactosidase (SA beta-gal) staining of hBMSCs showed 10% in passage 9 and 45% in passage 11. We detected an increase in endogenous superoxide levels during senescence that correlated with senescence markers (SA beta-gal, hyperbolic growth curve). Interestingly, even though endogenous superoxide increased in a replicative senescence model, the expression of APE1/Ref-1, which is sensitive to intracellular redox state, decreased. These effects were confirmed in a stress-induced senescence model by exogenous treatment with H(2)O(2). This change is related to the p53 activity that negatively regulates APE1/Ref-1. p21 expression levels, which represent p53 activity, were transiently increased in passage 9, meaning that they correlated with the expression of APE1/Ref-1. Overexpression of APE1/Ref-1 suppressed superoxide production and decreased SA beta-gal in hBMSCs. In conclusion, intracellular superoxide accumulation appears to be the main cause of the senescence of hBMSCs, and overexpression of APE1/Ref-1 can rescue cells from the senescence phenotype. Maintaining characteristics of hBMSCs by regulating intracellular reactive oxygen species production can contribute to tissue regeneration and to improved cell therapy.</P>

      • KCI등재

        Effect of Pine Wilt Disease Control on the Distribution of Ground Beetles (Coleoptera: Carabidae)

        Heo, Young-Jin,Ha, Man-Leung,Park, Jun-Young,Lee, Snag-Gon,Lee, Chong-Kyu Institute of Forest Science 2019 Journal of Forest Science Vol.35 No.4

        We chose the Mt. Dalum area (located in Gijang-gun, Busan, Korea) for our survey, particularly The pine wilt disease zone and the non-permanent control area. This study investigates the effect of pine wilt disease on the distribution of beetle species in the process of ecosystem change due to insect control; pine forests treated for pine wilt disease were divided into insect control and non-control sites, respectively. The results of this study are as follows. Twen tyseven species belongs to 12 families were identified from 969 ground beetles collected from this sites. Species richness was the highest in Coleoptera (6 species, 469 individuals). In the control site, 21 species belongs to 10 families were identified from 228 individuals, while 24 species of 11 families from 533 individuals in the non-control area. The highest number of species were noted in June and July from the non- control and control sites, respectively. The highest number of insects in control and non-control sites was observed in July, while the lowest in September. Sipalinus gigas gigas, Spondylis buprestoides, Plesiophthalmus davidis, Calosoma maximowiczi, Damaster jankowskii jankowskii, and Damaster smaragdinus were captured in both study sites. Episomustur ntus and Glischrochilus ipsoides were only captured in the control site, while Macrodorcas rectus rectus and Pheropsophus javanus were only captured in the non-control site. Six beetles and five species (such as Calosoma maximowiczi) were found in the control site and six species (including Damaster smaragdinus) in the non-control site. The species distributions by altitude were 163, 518, and 258 individuals, at 100, 200 and 300 m sites, respectively. The diversity, evenness, and dominance indices in the control area were 0.764, 0.812, and 0.367, respectively. The diversity, evenness, and dominance indices in the non-control area were 0.927, 0.837, and 0.352, respectively. The similarity index between the control and non-control area was 80%.

      • An integrative process for obtaining lipids and glucose from <i>Chlorella vulgaris</i> biomass with a single treatment of cell disruption

        Heo, Young Mok,Lee, Hanbyul,Lee, Changsu,Kang, Juwon,Ahn, Joon-Woo,Lee, Young Min,Kang, Kyu-Young,Choi, Yoon-E,Kim, Jae-Jin Elsevier 2017 Algal research Vol.27 No.-

        <P><B>Abstract</B></P> <P>To examine the possibility of better utilizing <I>Chlorella vulgaris</I> biomass including its carbohydrate as well as lipid contents, it was investigated whether cell disruption for lipid extraction could render the remaining microalgal residue (MR) suitable for enzymatic saccharification, possibly due to the disruption of cell wall structures. The <I>C. vulgaris</I> biomass was subjected to lipid extraction with different cell disruption methods (autoclaving, microwave irradiation, osmotic shock, and sonication), and recovered MRs were hydrolyzed using an enzyme produced from <I>Trichoderma koningiopsis</I> KUC21269 in this study. The enzyme was produced on-site with a highly simplified medium of barley straw, an agricultural byproduct. As a result, the saccharification rate of MR treated with microwave was more than twice that of the control group, and microwave irradiation appeared to be a promising method for both lipid extraction and subsequent saccharification. Our results suggested that both lipids and carbohydrates in <I>C. vulgaris</I> can be utilized by applying proper cell disruption method and a fungal enzyme produced on-site using an agricultural byproduct, respectively. This study revealed the high potential of <I>C. vulgaris</I> as an integrated bio-resource for both lipids and glucose, which can be converted to biodiesel and bioethanol, providing clues for overcoming hurdles in economically feasible biofuel production using microalgae.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Both lipids and glucose in <I>C. vulgaris</I> could be obtained with a single treatment. </LI> <LI> Cell disruption for lipid extraction could also damage cell wall structures. </LI> <LI> Lipid-extracted residues were hydrolyzed using a fungal enzyme produced on-site. </LI> <LI> Saccharification rate was more than doubled by microwave irradiation. </LI> <LI> Microwave irradiation enhanced the bioaccessibility of cellulose in the cell walls. </LI> </UL> </P>

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