• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.259-264
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• 2006

In MT and GDS survey for probing the deep structure of the Earth, surrounding seas play a critical role to distort the response of in-land geological structure. This study analyzed the sea effect in the Korean Peninsula and investigated the spatial and frequency dependency of it using 2-D MT modeling. Due to conductance difference between the Yellow Sea and the East Sea, the effect of each sea shows the dependence on frequency and spatial distance from each coastline. In general, TM mode responses are more severely affected by surrounding sea than TE mode one and the differences between 1-D model and TM mode responses are in inverse proportion to the frequency. Assuming that the lowest limit of acquired frequency is 0.001Hz for the given 1-D structure, the separation distance, where the sea effect can be negligible, is approximately 100km for the East Sea and 40-50km for the Yellow Sea, respectively. But, this separation distance is a function of the 1-D electrical structure of subsurface and the used frequency.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.4
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• pp.265-270
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• 2003

This study was conducted to determine the influence of seeding date on growth, characteristic yield and chemical composition of Italian millet (Setaria italica) from April 20 to May 30, 2003(April 20, May 1, May 20 and May 30) in Jeju. A local variety was seeded on days to heading were lessened as seeding date was delayed. The plant height was longest when seeded on 1 May(131cm) than at the other seeding dates. Stem diameter, number of leaves, leaf length and leaf width had the similar trend with plant height. SPDA reading values were greater at earlier seedings. Fresh forage yield was greatest (43.28MT/ha) at 1 May seeding and decreased gradually before or after this seeding date. Dry matter yield, crude protein yield and total digestible nutrient (TDN) yield had nearly the same tendency with fresh forage yield. Crude protein, crude fat, NFE and TDN contents were greatest at 30 May seeding and then decreased earlier seedings. Crude ash and crude fiber content tended to decreased as seeding was delayed. Based on the these findings, optimum seeding date for forage production of Italian millet seems to be early May in Jeju island.

• Ocean and Polar Research
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• v.26 no.2
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• pp.187-197
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• 2004

The purpose of this paper is to investigate economic feasibility of manganese nodules in Korea area (Clarion-Clipperton Fracture Zone). We assumed that the production scale of manganese nodules were 3.0MT or 1.5MT and analyzed that the capital cost and operating cost were estimated in the four sectors, exploration, mining, transportation and metallurgical process. The capital cost and operating cost evaluation reflects the latest technical practices. First, for analyzing economic feasibility, the scenario suggests that the production of 4 metals can be made for 25 years. Assuming the discount rate at 8.0%, equity capital at 50% and tax at 27%. When manganese nodule were mininged 3.0 MT, economic feasibility analyses showed that IRR was 12.8 and pay-back period was 9.2 years, and when manganese nodules were mininged 1.5 MT, economic feasibility analyses showed that IRR was 4.0 and pay-back period was 11.8 years. This study indicated there is economic validity of at the product of manganese nodules 3.0 MT. In addition, we carried out a sensitivity analysis at the change of cobalt price on mining 1.5 MT. The result of sensitivity analysis clearly showed that economic validity is high at increasing of cobalt price 50% up.

• Environmental Analysis Health and Toxicology
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• v.19 no.3
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• pp.261-269
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• 2004

Although the biological functions of metallothioneins (MTs) are still being investigated, they have been suggested to be involved in detoxification of heavy metals, scavenging of free radicals, and protection against alkylating agents. MTs have been reported to be induced in most of animal tissues by heavy metals such as zinc, copper, mercury and cadmium, and the proteins have binding affinities to the metals. However, the presence or induction of MTs was reported not to be clear in leydig cells, which produce testosterone for the maturation of spermatozoa in male testes. In this study, we investigated the inducibility of metallothionein isomers by cadmium in cultured mouse leydig cells. Total RNA was extracted from the near confluent grown leydig cells and RT-PCR was Performed using the Primers which were synthesized on the basis of MT-1, 2, 3 and 4 cDNA from GenBank database. As results, MT-1 and MT-2 mRNA were found to be expressed in cadmium non-treated control cells and MT 1 mRNA expression was dose-dependent when leydig cells were treated with cadmium chloride. But MT-3 which is known to be brain specific and MT-4 which is another isoform of metallothionein, were not expressed. Other genes induced or depressed in cadmium treated leydig cells were also identified by microarray techniques.

• Korean Journal of Remote Sensing
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• v.30 no.3
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• pp.341-350
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• 2014

Landsat images can monitor the snow-covered Earth surface variations with the ground resolution of 30m and the multi-spectral bands in the visible, NIR, SWIR and TIR spectral regions for the last 30 years. The Southern Volcanic Zone (SVZ) of Chile consists of many volcanoes, and all of the volcanoes are covered with snow at the top of mountain. Snow cover area in southern province of the SVZ of Chile (37 to $46^{\circ}S$) have been influenced by significant frontal retreats as well as eruptive activities. In this study, we have investigated the changes of the snow-cover area and snow-line elevation at Mt. Villarrica and Mt. Llaima, Chile from three Landsat images acquired on Feb. 1990, 2005 and 2011. The snow-cover areas are 13.42, 26.75 and $21.60km^2$ at Mt. Villarrica in 1990, 2005 and 2011, respectively, and 3.82, 25.12 and $8.89km^2$ at Mt. Llaima in 1990, 2005 and 2011, respectively. The snow-line elevations are 1871, 1738 and 1826m at Mt. Villarrica in 1990, 2005 and 2011, respectively, and 2007, 1822 and 1818m at Mt. Llaima in 1990, 2005 and 2011, respectively. The results indicate that both of the snow-cover and snow-line changes are strongly related with the volcanic activity change. The results demonstrate that the snow-cover area and snow-line elevation changes can be used as an indicator of the volcanic activity at Mt. Villarrica and Mt. Llaima, Chile.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.1
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• pp.7-12
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• 2003

This study was conducted to determine the influence of seeding date (May 3, 13, 23, June 2, 12) on the growth characteristics yield and feed value Azuki bean(Vigna angularis W.F. Wight) from May 3, 2002 to August 3, 2002 in Jeju province. Plant height was the longest (84cm) when seeded on 13 May and was the shortest (48.4cm) when seeded on 12 June. Numbers of branches and leaves per plant, stem diameter and weight of leaves and stems per plant were the same trend with plant height. Fresh forage, fry matter, crude protein and TDN(total digestible nutrient) yield per ha at were increased to 54.6MT, 7.7MT, 1.4MT and 4.5MT, respectively, whereas decreased as seeding date was delayed and then at seeding on 12 June were decreased to 11.5MT/ha 2.12MT/ha 0.4MT/ha and 1.3MT/ha, respectively The content of crude protein, crude fat, NFE(nitrogen free extract) and TDN were incresed 17.6%∼21.3%, 3.3%∼4.5%, 34.3%∼41.4% and 56%∼64.8%, respectively, as seeding was delayed from 3 May to 13 June. Whereas the content of crude fiber and crede ash were decreased 33.8%∼23.5% and 11%∼9.3％, respectively.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3409-3416
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• 2012

Aim: It is well known that polycyclic aromatic hydrocarbons (PAHs) such as benzo (a) pyrene have carcinogenic properties and may cause many types of cancers in human populations. Genetic susceptibility might be due to variation in genes encoding for carcinogen metabolizing enzymes, such as cytochrome P-450 (CYP450). Our study aimed to investigate the effect of genetic polymorphisms of CYP1A1 (m1 and m2) on genetic damage in 115 coal-tar workers exposed to PAHs at their work place. Methods: Genetic polymorphisms of CYP1A1 were determined by the PCR-RFLP method. Comet and buccal micronucleus assays were used to evaluate genetic damage among 115 coal tar workers and 105 control subjects. Results: Both CYP1A1 m1 and CYP1A1 m2 heterozygous and homozygous (wt/mt+mt/mt) variants individually as well as synergistically showed significant association (P<0.05) with genetic damage as measured by tail moment (TM) and buccal micronuclei (BMN) frequencies in control and exposed subjects. Conclusion: In our study we found significant association of CYP1A1 m1 and m2 heterozygous (wt/mt)+homozygous (mt/mt) variants with genetic damage suggesting that these polymorphisms may modulate the effects of PAH exposure in occupational settings.

• Geophysics and Geophysical Exploration
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• v.22 no.2
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• pp.62-71
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• 2019

We conducted DC resistivity and MT survey to obtain the resistivity structure of the central Myanmar basin. We tried to analyze the underground structure through the resistivity variation of Myanmar by performing representative geophysical survey methods because researches on the electrical resistivity structure are insufficient in Myanmar. The electrical resistivity is expected to be low considering the marine sedimentary rocks composed of shale and sandstone in this area. The DC resistivity and MT survey were carried out using SmartRho of Geolux Co., Ltd. and MTU-5A of Phoenix geophysics Ltd., respectively, to visualize the electrical resistivity structure of study area. DC resistivity and MT survey showed an electrical resistivity less than dozens of ohm-m within the depth of 100 m. In particular, MT survey data were almost similar to TM and TE modes in the frequency range above 1 Hz. The two-dimensional inversion of MT data showed a subsurface structure with low resistivity below 150 ohm-m divided into east-west direction. We confirmed that the inversions of DC resisitivity and MT data along an overlapped survey line represented similar results. In the future, considering the high electrical conductivity, it would be effective to perform DC resistivity and MT survey simultaneously to study the electrical resistivity structure of the central Myanmar basin.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.84.1-84.1
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• 2015

The Baptistina family is one of the typical young asteroid families with an age estimated to be about 140-320 Myrs old (Masiero et al. 2012); considered to have not enough time to experience a significant collisional and dynamical evolution since it was formed. Therefore, it may offer a unique insight into spin rate distribution of relatively fresh fragments and physical mechanism of a family break-up event. Observations of the Baptistina family asteroids were conducted during 111 nights from 2013 Oct. to 2015 Feb., using 0.5 m- to 2 m- class telescopes at 6 observatories in the northern hemisphere. We used CCD cameras on the Sobaeksan Optical Astronomy Observatory (SOAO) 0.6 m telescope on Mt. Sobaek, Korea, the Lemmonsan Optical Astronomy Observatory (LOAO) 1.0 m telescope on Mt. Lemmon, USA, the Tubitak Ulusal Gozlemevi (TUG) 1.0 m telescope in Bakirlitepe, Turkey, the Bohyunsan Optical Astronomy Observatory (BOAO) 1.8 m telescope on Mt. Bohyun, Korea, the McDonald Observatory 2.1 m Otto Struve Telescope on Mt. Locke, USA, and the National Astronomical Research Institute of Thailand (NARIT) Observatory 2.4 m telescope on Mt. Doi Inthanon, Thailand. Here, we will present our preliminary results for lightcurve analyses of Baptistina family members.

• Tuberculosis and Respiratory Diseases
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• v.50 no.5
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• pp.579-590
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• 2001

Background : The aging process may be induced, at least in part, by reactive oxygen species(ROS). It has been thought that the lung could be a good source of ROS because it has a high oxygen tension. In the present study, we invetigated the inducibility of the first and last lines against oxidative stress, superoxide dismutases(CujZn-SOD and Mn-SOD) as a scavenger of ${O_2}^-\;{\cdot}$ and metallothionein(MT) as a scavenger of $OH{\cdot}$, respectively, in mouse lungs with age. Methods : Oxidative stress was induced by paraquat, an intracellular superoxide generator, at 1, 4, 8, and 12 months of age and then SODs and MT mRNAs were determined by RT-PCR method. Results : The steady-state level of Mn-SOD mRNA increased from 1 to 8 months but decreased thereafter. However, Mn-SOD mRNA was not induced by paraquat after 1 month. On the other hand, there was no change in the steady-state level of Cu/Zn-SOD mRNA, which decreased abruptly at 12 months of age. Additionally, Cu/Zn-SOD mRNA was not induced by paraquat at any age. There was no change in the steady-state level of MT mRNA with age whereas its inducibility by paraquat was intact at all ages. Conclusion : These results indicate that lack of induction of SODs with age may be one of the causative factors in the aging process while induction of MT may play an important role in the defense against oxidative stress. It is therefore implicated that the tissue antioxidant/prooxidant balance could be one of determinants of mean life span.