• Title/Summary/Keyword: Tail Moment

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Local Field Distribution in YNi$_2B_2C$ Superconductor (YNi$_2B_2C$의 초전도 상태에서 국소자기장의 분포)

  • Kim, Do-Hyeong;Lee, Kyu-Ho;Han, Ki-Seong;Seo, Seung-Won;Lee, Moo-Hee;Lee, Seong-Ik;Cho, Byeong-Ki
    • 한국초전도학회:학술대회논문집
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    • v.9
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    • pp.251-255
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    • 1999
  • Local field distribution in the mixed state of type II superconductors has been numerically calculated and compared with $^{11}$B NMR spectra for YNi$_2B_2C$ single crystals. We find that only small distortion of vortex positions from the perfect lattice points is enough to smear out the low frequency shoulder. As the vortices are further distorted, the line shape changes from an asymmetric shape with a high frequency tail to a symmetric Gaussian line shape. It is found that the second moment of the field distribution has a major contribution from the high frequency tail. Consequently, a linewidth of the full width at half maximum calculated from the second moment assuming for a Gaussian line shape is overestimated.

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Evaluation of DNA damage in Pesticide Sprayers using Single Cell Gel Electrophoresis (단세포전기영동법(single Cell Gel Electrophoresis Assay)을 이용한 농약 살포자의 DNA손상 평가)

  • 이연경;이도영;이은일;이동배;류재천;김해준;설동근
    • Environmental Mutagens and Carcinogens
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    • v.21 no.2
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    • pp.128-134
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    • 2001
  • Single cell gel electrophoresis (SCGE) assay, also called comet assay, is a rapid and sensitive method to detect DNA damage in single cell level. To evaluate the DNA damage of lymphocytes of pesticides sprayers, SCGE assay was carried out for 50 pesticides sprayer and 58 control subjects. They were interviewed with structured questionnaire to get the information about the kinds and amount of pesticide. Insecticides and fungicides were predominant among pesticides. Major components of pesticides were organophosphorus, organosulfate, cartap, carbamates, and triazole. Sprayed pesticides were classified into two groups. Group I included organophosphorus, organoarsenic, organotin, tetrazine, triazole and gramoxone, which were known to cause DNA damages. Group II pesticide were carbamates, surfactants, organosulfates, etc., which were not found as DNA damaging agents in scientific documents. Olive tail moments of 100 lymphocytes were measured by KOMET 3.1 program for each person. The means of tail moments were compared between farmers exposed to pesticides and control subjects. Farmers showed higher tail moments than control subjects (2.07$\pm$1.40 vs 1.53$\pm$0.77, p<0.05). The means of tail moments also were compared among group I sprayers (n=36), group II sprayers (n=24) and, control subject, and the means or tail moments were 3.4s$\pm$3.2o, 2.66$\pm$2.20 and 1.53$\pm$0.77 respectively. The difference between means of group I sprayers and controls was statistically significant (p<0.05). In conclusion, this study showed higher DNA damage in farmers exposed to pesticides than control subjects, and comet assay could be useful as a biological monitoring method of genotoxic pesticides for farmers.

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Controlled Flight of Tailless Insect-Like Flapping-Wing Flying-Robot (꼬리날개 없는 곤충모방 날갯짓 비행로봇의 제어비행)

  • Phan, Hoang Vu;Kang, Taesam;Park, HoonCheol
    • The Journal of Korea Robotics Society
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    • v.11 no.4
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    • pp.256-261
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    • 2016
  • An insect-like flapping-wing flying-robot should be able to produce flight forces and control moments at the same time only by flapping wings, because there is no control surface at tail just like an insect. In this paper, design principles for the flapping mechanism and control moment generator are briefly explained, characteristics measured force and moment generations of the robot are presented, and finally controlled flight of the flying robot is demonstrated. The present insect-like robot comprises a lightweight flapping mechanism that can produce a flapping angle larger than $180^{\circ}$ and a control moment generator that produces pitch, roll, and yaw moments by adjusting location of the trailing edges at the wing roots. The measured force and moment data show that the control input angles less than $9^{\circ}$ would not significantly reduce the vertical force generation. It is also observed that the pitch, roll, and yaw control moments are produced only by the corresponding control input. The simple PID control theory is used for the controlled flight of the flying robot, controlling pitch, roll, and yaw motions. The flying robot successfully demonstrated controlled flight for about 40 seconds.

Aerodynamic Force Measurement of Counter-Rotating System (동축 반전 시스템의 공력측정)

  • Kim, Su-Yean;Choi, Jong-Wook;Kim, Sung-Cho
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.39-42
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    • 2008
  • In the case of the general helicopter among rotorcraft, length of the rotor blade for thrust-generation is longer than that of fuselage and tail rotor is required in order to compensate moment of the fuselage. For those reasons, enough space for take-off and landing should be secured and an accessibility for building is low. Also, the accidents caused by tail rotor occur frequently. However, the case of counter-rotating has merits that tail rotor is unnecessary as well as length of the rotor blade can be shortened but has a weakness that the weight of body is increased. In the present study, aerodynamic force measurement on single rotor system equipped with NACA0012 airfoil, which has aspect ratio of 6 and chord length of 35.5 mm, was carried out. And measurement was conducted with blade which has a half size of the former blade by using single motor counter-rotating. Aerodynamic force measurement was acquired by using 6-component balances and coefficients of thrust and power were derived along the pitch angle varying from 0$^{\circ}$ to 90$^{\circ}$ with the increment of 10$^{\circ}$. Those aerodynamic force data will be utilized for the design and production of brand-new counter-rotating rotor blade system which has same thrust with single blade system and provides a good accessibility to building by reducing its blade length.

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Design of Whirl Tower Test Facility for Helicopter Rotor System (헬리콥터 로터시스템 회전시험설비의 설계)

  • Kim, Seung-Bum;Song, Keun-Woong;Choi, Hee-Ju;Kim, Eun-Jong;Park, Byung-Kwan
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1136-1141
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    • 2008
  • The helicopter rotor system generates lift, thrust, maneuvering force and moment to the helicopter with the torque and pitch control force transferred from the main rotor hub/control. And the tail rotor system generates the thrust for yaw axis control of the helicopter with the torque and pitch control force transferred from the tail rotor hub/control. Ground whirl test shall be performed to verify the compliance of requirement performance test and dynamic test of rotor blade and hub/control. This paper describes a design of whirl tower test facility for helicopter rotor system test and evaluation. Design results are summarized and compared with design requirements.

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Radiation Protective Effect of vitamin C and Cysteine on DNA Damage in Mice Splenic Lymphocytes by Single Cell Gel Electrophoresis Assay (단세포 겔 전기영동법을 이용한 생쥐 비장 림프구 DNA 손상에 대한 비타민 C 및 시스테인의 방사선 방어효과)

  • 천기정;김진규;김봉희
    • Environmental Analysis Health and Toxicology
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    • v.16 no.1
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    • pp.17-20
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    • 2001
  • The alkaline comet assay, employing a single-cell gel electrophoresis(SCGE), is a rapid, simple and sensitive technique for visualizing and measuring DNA damage leading to strand breakage in individual mammalian cells. The protecting effect of pretreatment with vitamin C and cysteine on the DNA damage of gamma ray was investigated in mice splenic lymphocytes. Vitamin C and cysteine were administered orally for five consecutive days before irradiation. Four week old ICR male mice were irradiated wish 3.5Gy of γ-radiation and were sacrificed 3 days later. Spleens were taken for DNA damage examination by Comet assay and the tail moments of DNA single -strand breaks in tole splenic lymphocytes were evaluated. The results show that pretreatment with vitamin C and cysteine were effective in protecting against DNA damage by gamma ray. Administration of antioxidants like vitamin C and cysteine to mice before irradiation was effective in reducing the tail moment of splenic lymphocytes DNA.

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Effects of lymphocyte DNA damage levels in Korean plant food groups and Korean diet regarding to glutathione S-transferase M1 and T1 polymorphisms (건강한 성인의 glutathione S-transferase M1과 T1 유전자 다형성에 따른 한식에서의 식물성 식품군과 한식의 DNA 손상 감소 효과)

  • Kim, Hyun-A;Lee, Min-Young;Kang, Myung-Hee
    • Journal of Nutrition and Health
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    • v.50 no.1
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    • pp.10-24
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    • 2017
  • Purpose: GST (glutathione S-transferase) M1 and T1 gene polymorphisms are known to affect antioxidant levels. This study was carried out to evaluate genetic susceptibility by measuring the effect of DNA damage reduction in the Korean diet by vegetable food according to GST gene polymorphisms using the ex vivo method with human lymphocytes. Methods: Vegetable foods in the Korean diet based the results of the KNHANES V-2 (2011) were classified into 10 food groups. A total of 84 foods, which constituted more than 1% of the total intake in each food group, were finally designated as a vegetable food in the Korean diet. The Korean diet applied in this study is the standard one-week meals for Koreans (2,000 Kcal/day) suggested by the 2010 Dietary Reference Intakes for Koreans. Ex vivo DNA damage in human lymphocytes was assessed using comet assay. Results: In the Korean food group, the DNA damage protective effect of GSTM1 and GSTT1 was found to be greater in mutant type and wild-type, respectively. and the DNA damage protective effect according to the combined genotype of GSTM1 and GSTT1 was different depending on the food group. On the other hand, in Korean Diet, the DNA damage protective effect appeared to be larger in GSTM1 wild-type than in mutant type and was found to not be affected by GSTT1 genotype. Conclusion: These results can be used as basic data to demonstrate the superiority of the antioxidant function of Korean dietary patterns and food groups. Furthermore, it may be a starting point to begin research on customized antioxidant nutrition according to individual genes.

Antimutagenic Effects of Ginsenoside Rb$_1$, Rg$_1$ in the CHO-K1 Cells by Benzo[a]pyrene with Chromosomal Aberration Test and Comet Assay

  • Kim, Jong-Kyu;Kim, Soo-Jin;Rim, Kyung-Taek;Cho, Hae-Won;Kim, Hyeon-Yeong;Yang, Jeong-Sun
    • Molecular & Cellular Toxicology
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    • v.5 no.2
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    • pp.126-132
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    • 2009
  • The usage and types of chemicals are advancing, specializing, large-scaled increasing, and new chemical exposed workers are concerning to occupational disease. The generation of reactive oxygen in the body from carcinogen, mutation and DNA damage in cancer is protected by natural antioxidants (phytochemicals) with antimutagenic effect. There were many reports of ginsenoside Rb$_1$, Rg$_1$ grievances of the genetic mutation to suppress the effect confirm the genetic toxicity test with chromosomal aberration test and the Comet (SCGE) assay confirmed the suppression effect occurring chromosomal DNA damage. We had wanted to evaluate the compatibility and sensitivity between the chromosomal aberration (CA) test and the Comet assay. We used the CA test and Comet assay to evaluate the anti-genotoxicity of ginsenoside Rb$_1$ and Rg$_1$, in CHO-K1 (Chinese hamster ovary fibroblast) cell in vitro, composed negative control (solvent), positive control (benzo[a]pyrene), test group (carcinogen+variety concentration of ginsenoside) group. The positive control was benzo[a]pyrene (50 $\mu$M), well-known carcinogen, and the negative control was the 1 % DMSO solvent. The test group was a variety concentration of ginsenoside Rb$_1$, Rg$_1$ with 10$^{-8}$%, 10$^{-6}$%, 10$^{-4}$%, 10$^{-2}$%, 1%, 10%. In chromo-somal aberration test, we measured the number of cells with abnormally structured chromosome. In Comet assay, the Olive tail moment (OTM) and Tail length (TL) values were measured. The ratio of cell proliferation was increased 8.3% in 10$^{-8}$%, 10$^{-6}$%, 10$^{-4}$%, 10$^{-2}$%, 1%, 10% Rb$_1$ treated groups, and increased 10.4% in 10$^{-10}$%, 10$^{-8}$%, 10$^{-6}$%, 10$^{-4}$%, 10$^{-2}$%, 1% Rg$_1$ treated groups. In the CA test, the number of chromosomal aberration was decreased all the Rb$_1$ and Rg$_1$ treated groups. In the Comet assay, the OTM values were decreased in all the Rb$_1$ and Rg$_1$ treated groups. To evaluate the compatibility between CA and Comet assay, we compared the reducing ratio of chromosomal abnormalities with its OTM values, it was identified the antimutagenicity of ginsenoside, but it was more sensitive the CA test than the Comet assay. Ginsenoside Rb$_1$ and Rg$_1$ significantly decrease the number of cells with chromosomal aberration, and decrease the extent of DNA migration. Therefore, ginsenoside Rb$_1$, Rg$_1$ are thought as an antioxidant phytochemicals to protect mutagenicity. The in vitro Comet assay seems to be less sensitive than the in vitro chromosomal aberration test.

Development of Load Factors Based on Optimum Reliability Analysis Model (하중 계수에 기초한 최적신뢰성해석 모델 개발)

  • 이증빈;신형우
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1992.04a
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    • pp.134-139
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    • 1992
  • This study introduces simple derivation of optimum load factors based on both cornell's MFOSM (Mean First Order End Moment) methods and Lind - Hasofers AFOSM (Advanced First Order 2nd Moment) methods and demonstrates the relationship between the optimum reliability, the load factors, the probability distributions selected to model the load, and a measure of relative failure cost. Although some of the cost parameters cannot be evaluated accurately and the upper tail characteristics of the distributions of the random loads remain uncertainty, this optimum reliability formulation provides insight on which Parameters are most significant in selecting appropriate load criteria for structure design.

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Estimations of the skew parameter in a skewed double power function distribution

  • Kang, Jun-Ho;Lee, Chang-Soo
    • Journal of the Korean Data and Information Science Society
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    • v.24 no.4
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    • pp.901-909
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    • 2013
  • A skewed double power function distribution is defined by a double power function distribution. We shall evaluate the coefficient of the skewness of a skewed double power function distribution. We shall obtain an approximate maximum likelihood estimator (MLE) and a moment estimator (MME) of the skew parameter in the skewed double power function distribution, and compare simulated mean squared errors for those estimators. And we shall compare simulated MSEs of two proposed reliability estimators in two independent skewed double power function distributions with different skew parameters.