• Tuberculosis and Respiratory Diseases
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• v.77 no.3
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• pp.116-123
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• 2014

Background: Mesenchymal stem cells (MSCs) obtained from bone marrow or adipose tissue can successfully repair emphysematous animal lungs, which is a characteristic of chronic obstructive pulmonary disease. Here, we describe the cellular distribution of MSCs that were intravenously injected into mice with elastase-induced emphysema. The distributions were also compared to the distributions in control mice without emphysema. Methods: We used fluorescence optical imaging with quantum dots (QDs) to track intravenously injected MSCs. In addition, we used a human Alu sequence-based real-time polymerase chain reaction method to assess the lungs, liver, kidney, and spleen in mice with elastase-induced emphysema and control mice at 1, 4, 24, 72, and 168 hours after MSCs injection. Results: The injected MSCs were detected with QD fluorescence at 1- and 4-hour postinjection, and the human Alu sequence was detected at 1-, 4- and 24-hour postinjection in control mice (lungs only). Injected MSCs remained more in mice with elastase-induced emphysema at 1, 4, and 24 hours after MSCs injection than the control lungs without emphysema. Conclusion: In conclusion, our results show that injected MSCs were observed at 1 and 4 hours post injection and more MSCs remain in lungs with emphysema.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.245-271
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• 2012

A study on the indigenous diatoms was carried out at 103 sites during August 2008 to April 2011 from the marine and the brackish waters in Korea. A fine structure of small-sized diatoms was examined using a light and scanning electron microscopy. Sixty species of diatoms were newly identified and composed of 3 class, 6 subclass, 16 order, 21 family and 39 genus. The detailed nomenclatures, references, photographs and distributions were here reported. Of 60 species, the most frequent species was Tryblionella coarctata appearing 24 times, and 22 times followed by Thalassiosira lacustris, Cocconeis stauroneiformis was 20 times. In the level of genus, Chaetoceros, Parlibells and Thalassiosira were included 4 species, Actinocyclus, Minidiscus and Licmophora were included 3 species. This study will provide the knowledge of the diversity level of diatom in Korea, the knowledge is important on the diatoms for further studies.

• Journal of the Korean Statistical Society
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• v.28 no.4
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• pp.415-433
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• 1999

This paper considers the design of step-stress accelerated life tests for the Weibull distribution with a nonconstant shape parameter under Type I censoring. It is assumed that scale and shape parameters are log-linear functions of (possibly transformed) stress and that a cumulative exposure model holds for the effect of changing stress. The asymptotic variance of the maximum likelihood estimator of a stated quantile at design stress is used as an optimality criterion. The optimum three step-stress plans are presented for selected values of design parameters and the effects of errors in pre- estimates of the design parameters are investigated.

• International Journal of Reliability and Applications
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• v.9 no.2
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• pp.125-140
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• 2008

The new better than used failure rate (NBUFR), Abouammoh and Ahmed (1988), and new better than average failure rate (NBAFR) Loh (1984) classes of life distributions, have been considered in the literature as natural weakenings of NBU (NWU) property. The paper considers testing exponentiality against strictly NBUFR (NBAFR) alternatives, or their duals, based on goodness of fit approach that is possible in life testing problems and that it results in simpler procedures that are asymptotically equivalent or better than standard ones. They may also have superior finite sample behavior. The asymptotic normality are proved. Powers, Pitman asymptotic efficiency and critical points are computed. Dealing with censored data case also studied. Practical applications of our tests in the medical sciences are present.

• Journal of Ocean Engineering and Technology
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• v.16 no.1
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• pp.46-51
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• 2002

Fatigue life estimation by the theoretical stress concentration factors are, in general, considerably different from test results. And in calculating stress concentration factor, it is very difficult to consider actual geometry and material property which are the notch shapes, imperfections or defects of materials such as porosities inclusions and casting defects, etc. Therefore, the paper deals with the experimental method to find out the more exact stress concentration factors by measuring the strain distributions on each specimen by 3D-ESPI(Electronic Speckle Pattern Interferometry) System. Then the fatigue lives are compared between theoretical calculations using stress concentration factors determined by 3D-ESPI system and fatigue test results.

• Environmental Analysis Health and Toxicology
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• v.20 no.3 s.50
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• pp.249-258
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• 2005

Blood pressure, obesity and bone mineral density are multifactorial traits influenced by genetic factor. The purpose of this study was to clarify the association between three genetic polymorphisms in the estrogen receptor-$\alpha$ (ER -$\alpha$) gene and essential hypertension in korean population. One hundred and seventy-one people including 90 normotensives and 81 essential hypertentives were recruited. Among genetic polymorphisms studied, the Xba I RFLP in the intron 1 of this gene polymorphism was significantly associated with essential hypertension in women, suggesting the sexual dimorphism in genetic effect (P (<) 0.05). Further studied suggest that a larger sample size of this study are needed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.4
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• pp.395-400
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• 2009

As the variables affecting the fatigue behavior have uncertainty, the fatigue crack propagation is stochastic in nature. Therefore, the fatigue life prediction is critical for the design and the maintenance of many structural components. In this study, fatigue experiments are conducted on the specimens of magnesium alloy under the different thicknesses of specimen. The effects of specimen thickness on the probability distribution of the fatigue crack propagation life and the crack size are estimated experimentally. The probability distribution of the crack size and the fatigue life for different specimen thicknesses are investigated by Anderson-Darling test and the best fit for those probability distributions are also presented.

• Animal Systematics, Evolution and Diversity
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• v.30 no.3
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• pp.225-229
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• 2014

We report two new records of Korean fauna of genus Exochus, as well as two newly recorded species from China and Mongolia each. Specifically Exochus suborbitalis Schmiedeknecht, 1924 and Exochus thomsoni Schmiedeknecht, 1924 from Korea, Exochus kusigematii Tolkanitz, 2007 and Exochus suborbitalis Schmiedeknecht, 1924 from Mongolia and Exochus semilividus Vollenhoven, 1875 and Exochus thomsoni Schmiedeknecht, 1924 from China are reviewed. The genus Exochus have been reported 19 species from China and 21 species from Mongolia. Diagnosis of the four unrecorded species, host information, distributions and illustrations of external characters are provided.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.28-34
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• 2006

A procedure of estimating failure probability is demonstrated for a pressurized pipe of CrMo steel used at $538^{\circ}C$. Probabilistic fracture mechanics were employed considering variations of pressure loading, material properties and geometry. Probability density functions of major material variables were determined by statistical analyses of implemented data obtained by previous experiments. Distributions of the major variables were reflected in Monte Carlo simulation and failure probability as a function of operating time was determined. The creep crack growth life assessed by conventional deterministic approach was shown to be conservative compared with those obtained by probabilistic one. Sensitivity analysis for each input variable was also conducted to understand the most influencing variables to the residual life analysis. Internal pressure, creep crack growth coefficient and creep coefficient were more sensitive to failure probability than other variables.

• International Journal of Reliability and Applications
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• v.15 no.1
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• pp.65-76
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• 2014

In this article, a new model based on Lomax distribution is introduced. This new model is both useful and practical in areas such as economic, reliability and life testing. Some statistical properties of this model are presented including moments, hazard rate, reversed hazard rate, mean residual life and mean inactivity time functions, among others. It is also shown that the distributions of the new model are ordered with respect to the strongest likelihood ratio ordering. The method of moment and maximum likelihood estimation are used to estimates the unknown parameters. Simulation is utilized to calculate the unknown shape parameter and to study its properties. Finally, to illustrate the concepts, the appropriateness of the new model for real data sets are included.