• Journal of Life Science
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• v.26 no.11
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• pp.1313-1319
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• 2016

Cancer is a complex disease heterogeneously composed of various types of cells including cancer stem-like cells responsible for relapse and chemoresistance in the tumor microenvironment. The conventional two-dimensional cell culture-based platform has critical limitations for representing the heterogeneity of cancer cells in the three-dimensional tumor niche in vivo. To overcome this insufficiency, three-dimensional cell culture methods in a scaffold-dependent or -free physical environment have been developed. In this study, we improved and simplified the HCT-8 colon cancer cell-based spheroid culture protocol and evaluated the relationship between cancer stemness and responses of chemosensitivity to 5- Fluorouracil (5-FU), a representative anticancer agent against colon cancer. Supplementation with defined growth factors in the medium and the culture dish of the regular surface with low attachment were required for the formation of constant-sized spheroids containing $CD44^+$ and $CD133^+$ colon cancer stem cells. The chemo-sensitivities of $CD44^+$ cancer stem cells in the spheroids were much lower than those of $CD44^-$ non-stem-like cancer cells, indicating that the chemoresistance to 5-FU is due to the stemness of colon cancer cells. Taken together, the inflammation and oncogenic gut environment-sensitive HCT-8 cell-based colon cancer spheroid culture and comparative evaluation using the simplified model would be an efficient and applicable way to estimate colon cancer stemness and pharmaceutical response to anticancer drugs in the realistic tumor niche.

• Clinical and Experimental Reproductive Medicine
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• v.33 no.3
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• pp.171-178
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• 2006

Objective: Human embryonic stem (ES) cells have a great potential in regenerative medicine and tissue engineering. The human ES cells could be differentiated into specific cell types by treatments of growth factors and alterations of gene expressions. However, the efficacy of guided differentiation and isolation of specific cells are still low. In this study, we characterized isolated cells from differentiated human ES cells by magnetic activated cell sorting (MACS) system using specific antibodies to cell surface markers. Methods: The undifferentiated hES cells (Miz-hESC4) were sub-cultured by mechanical isolation of colonies and embryoid bodies were spontaneously differentiated with DMEM containing 10% FBS for 2 weeks. The differentiated cells were isolated to positive and negative cells with MACS system using CD34, human epithelial antigen (HEA) and human fibroblast (HFB) antibodies, respectively. Observation of morphological changes and analysis of marker genes expression were performed during further culture of MACS isolated cells for 4 weeks. Results: Morphology of the CD34 positive cells was firstly round, and then it was changed to small polygonal shape after further culture. The HEA positive cells showed large polygonal, and the HFB positive spindle shape. In RT-PCR analysis of marker genes, the CD34 and HFB positive cells expressed endodermal and mesodermal genes, and HEA positive cells expressed ectodermal genes such as NESTIN and NF68KD. The marker genes expression pattern of CD34 positive cells changed during the extension of culture time. Conclusion: Our results showed the possibility of successful isolation of specific cells by MACS system from undirected differentiated human ES cells. Thus, MACS system and marker antibodies for specific cell types might be useful for guided differentiation and isolation of specific cells from human ES cells.

• Journal of radiological science and technology
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• v.31 no.2
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• pp.115-121
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• 2008

Purpose: Aortic Dissection is very dangerous, prognostic disease, which the bloodstream flow out of the true lumen of the aorta by the bursting of aortic intima resulting in a rapid dissociation of inner and outer layer from the media. It is difficult to diagnose aortic dissection clinically by normal X-ray. This study was to investigate the occurrence frequency by age and number of patients who are identified to be aortic dissection by CT (Computed Tomography) scan. Materials and methods: We investigated the trend of yearly fluctuation, gender, age, and department of clinical research of the 112 patients who conducted CT scan in C- University Hospital for two years from January 2005 to December 2006. The MIP and SSD which reconstructed CT image and the VRT image were obtained for the accurate observation. The result was investigated by comparing normal X-ray and CT scan. Results and Conclusion: 1. The yearly check of 112 patients conducted CT scan showed 37 people (41.9%) in 2005, and it was increased to 65 (58.1%) in 2006 by 1.4 times. 2. The gender distribution of patients given a CT scan showed 45 males (40.1%), and female 67 (59.9 %). The aortic dissection patients were 9 (20%) out of 45 males, 21 (31.3%) out of 67 females and women were 1.6 times more than men. Women are also 1.5 times more than men in the number of examinee. 3. The age distribution of patient's who conducted CT scan revealed that there was no patient under 30 years old while 88.3% of all patients were through 41 to 80 years old. The higher the age was, the higher the occurrence of aortic dissection was. The difference in the occurrence frequency of age was statistically significant (p<0.01). 4. The departments that requested CT scan were the emergency department 46 (41.1%), circulatory internal medicine 37 (33.0%), chest surgery 13 (11.6%), and others 6 (14.3%). The combined ratio of emergency medicine and circulatory internal medicine was 74.1% of all. The results show that the aortic dissection is a very dangerous disease whose patients visit mainly via the emergency room. 5. The aortic dissection patients had normal X-ray readings in 22 (73.3%) out of 30, and only 8 (26.7 percent) are abnormal in the X-ray diagnosis. Therefore, the CT scan needs to be enforced in order to assess accurately the disease of aortic dissection.

• Korean Journal of Remote Sensing
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• v.30 no.4
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• pp.525-536
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• 2014

In this study, a method to assess and monitor hydrological drought using remote sensing was investigated for use in regions with limited observation data, and was applied to the Upper Namhangang basin in South Korea, which was seriously affected by the 2008-2009 drought. Drought information may be obtained more easily from meteorological data based on water balance than hydrological data that are hard to estimate. Air temperature data at 2 m above ground level (AGL) were estimated using remotely sensed data, evapotranspiration was estimated from the air temperature, and the correlations between precipitation minus evapotranspiration (P-PET) and streamflow percentiles were examined. Land Surface Temperature data with $1{\times}1km$ spatial resolution as well as Atmospheric Profile data with $5{\times}5km$ spatial resolution from MODIS sensor on board Aqua satellite were used to estimate monthly maximum and minimum air temperature in South Korea. Evapotranspiration was estimated from the maximum and minimum air temperature using the Hargreaves method and the estimates were compared to existing data of the University of Montana based on Penman-Monteith method showing smaller coefficient of determination values but smaller error values. Precipitation was obtained from TRMM monthly rainfall data, and the correlations of 1-, 3-, 6-, and 12-month P-PET percentiles with streamflow percentiles were analyzed for the Upper Namhan-gang basin in South Korea. The 1-month P-PET percentile during JJA (r = 0.89, tau = 0.71) and SON (r = 0.63, tau = 0.47) in the Upper Namhan-gang basin are highly correlated with the streamflow percentile with 95% confidence level. Since the effect of precipitation in the basin is especially high, the correlation between evapotranspiration percentile and streamflow percentile is positive. These results indicate that remote sensing-based P-PET estimates can be used for the assessment and monitoring of hydrological drought. The high spatial resolution estimates can be used in the decision-making process to minimize the adverse impacts of hydrological drought and to establish differentiated measures coping with drought.

• Economic and Environmental Geology
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• v.45 no.6
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• pp.661-672
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• 2012

Lab scale experiments to investigate the dissolution reaction among supercritical $CO_2$-sandstone-groundwater by using sandstones from Gyeongsang basin were performed. High pressurized cell system (100 bar and $50^{\circ}C$) was designed to create supercritical $CO_2$ in the cell, simulating the sub-surface $CO_2$ storage site. The first-order dissolution coefficient ($k_d$) of the sandstone was calculated by measuring the change of the weight of thin section or the concentration of ions dissolved in groundwater at the reaction time intervals. For 30 days of the supercritical $CO_2$-sandstone-groundwater reaction, physical properties of sandstone cores in Gyeongsang basin were measured to investigate the effect of supercritical $CO_2$ on the sandstone. The weight change of sandstone cores was also measured to calculate the dissolution coefficient and the dissolution time of 1 g per unit area (1 $cm^2$) of each sandstone was quantitatively predicted. For the experiment using thin sections, mass of $Ca^{2+}$ and $Na^+$ dissolved in groundwater increased, suggesting that plagioclase and calcite of the sandstone would be significantly dissolved when it contacts with supercritical $CO_2$ and groundwater at $CO_2$ sequestration sites. 0.66% of the original thin sec-tion mass for the sandstone were dissolved after 30 days reaction. The average porosity for C sandstones was 8.183% and it increased to 8.789% after 30 days of the reaction. The average dry density, seismic velocity, and 1-D compression strength of sandstones decreased and these results were dependent on the porosity increase by the dissolution during the reaction. By using the first-order dissolution coefficient, the average time to dissolve 1 g of B and C sandstones per unit area (1 $cm^2$) was calculated as 1,532 years and 329 years, respectively. From results, it was investigated that the physical property change of sandstones at Gyeongsang basin would rapidly occur when the supercritical $CO_2$ was injected into $CO_2$ sequestration sites.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.4
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• pp.368-375
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• 2006

Single and complex metal oxide catalysts supported onto a commercial DT51D $TiO_2$ have been investigated for gas-phase TCE oxidation in a continuous flow type fixed-bed reaction system to develop a better design approach to catalysts for this reaction. Among the $TiO_2$-supported single metal oxides used, i.e., $CrO_x,\;FeO_x,\;MnO_x,\;LaO_x,\;CoO_x,\;NiO_x,\;CeO_x\;and\;CuO_x$, with the respective metal contents of 5 wt.%, the $CrO_x/TiO_2$ catalyst was shown to be most active for the oxidative TCE decomposition, depending significantly on amounts of $CrO_x\;on\;TiO_2$. The use of high $CrO_x$ loadings greater than 10 wt.% caused lower activity in the catalytic TCE oxidation, which is probably due to production of $Cr_2O_3$ crystallites on the surface of $TiO_2$. $CrO_x/TiO_2$-supported $CrO_x$-based bimetallic oxide catalysts were of particular interest in removal efficiency for this TCE oxidation reaction at reaction temperatures above $200^{\circ}C$, compared to that obtained with $CrO_x$-free complex metal oxides and a 10 wt.% $CrO_x/TiO_2$ catalyst. Catalytic activity of 5 wt.% $CrO_x-5$ wt.% $LaO_x$ in the removal reaction was similar to or slightly higher than that acquired for the $CrO_x$-only catalyst. Similar observation was revealed for 5 wt.% $CrO_x$-based bimetallic oxides consisting of either 5 wt.% $MnO_x,\;CoO_x,\;NiO_x\;or\;FeO_x$. These results represent that such $CrO_x$-based bimetallic systems for the catalytic TCE oxidation on significantly minimize the usage of $CrO_x$ that is well known to be one of very toxic heavy metals, and offer a very useful technique to design new type catalysts for reducing chlorinated volatile organic substances.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.5
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• pp.246-254
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• 2017

Microcystin-LR (MC-LR) is one of most abundant microcystins, and is derived from blue-green algae bloom. Advanced oxidation processes (AOPs) are effective process when high concentrations of MC-LR are released into a drinking water treatment system from surface water. In particular, UV-based AOPs such as UV, $UV/H_2O_2$, $UV/O_3$ and $UV/TiO_2$ have been studied for the removal of MC-LR. In this study, UV-LED was applied for the degradation of MC-LR because UV lamps have demonstrated some weaknesses, such as frequent replacements; that generate mercury waste and high heat loss. Degradation efficiencies of the MC-LR (initial conc. = $100{\mu}g/L$) were 30% and 95.9% using LED-L (280 nm, $0.024mW/cm^2$) and LED-H (280 nm, $2.18mW/cm^2$), respectively. Aromatic compounds of natural organic matter changed to aliphatic compounds under the LED-H irradiation by LC-OCD analysis. For application to raw water, the Nak-dong River was sampled during summer when blue-green algae were heavy bloom in 2016. The concentration of extracellular and total MC-LR, geosmin and 2-MIB slightly decreased by increasing the LED-L irradiation; however, the removal of MC-LR by UV-LED (${\lambda}=280nm$) was insufficient. Thus, advanced UV-LED technology or the addition of oxidants with UV-LED is required to obtain better degradation efficiency of MC-LR.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.1
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• pp.1-12
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• 2004

The summer distribution of $Cha-{alpha}$ and physical processes for simulating outbreak region of red tide were estimated by the Eco-Hydrodynamic model in Chinhae Bay. As a result of simulation of surface residual currents, the southward flow come in contact with the northward flow at the inlet and western part of bay in case of windlessness and below wind velocity 2 m/sec. As wind velocity increases, the velocity and direction of currents were fairly shifted. The predicted concentration of $Cha-{alpha}$ exceeded 20 mg/㎥ in Masan and Haengam Bays, and most regions were over 10 mg/㎥, which meant the possibility of red tide outbreak. From the results of the contributed physical processes to $Cha-{alpha}$, accumulation sites were distributed at the northern part of Kadok channel, around the Chilcheon island, the western part of Kajo island and some area of Chindong Bay. On the other hand, inner parts of the study area such as Masan Bay were estimated as the sites of strong algal activities. Masan and Haengam Bay are considered as the initial outbreak region of red tide by the modeling and observed data, and then red tide expanded to other areas such as physical accumulation region and western inner bay, as depending on environmental variation. The increase of wind velocity led to decrease of $Cha-{alpha}$ and enlargement of accumulation region. The variation of intensity of radiation and sunshine duration caused to rapidly fluctuation of $Cha-{alpha}$: however, it was not largely affected by the variation of pollutant loads from the land only.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.3
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• pp.138-149
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• 2008

Rapid accumulation of carbon dioxide in the atmosphere for the past century leads to acidify the surface ocean and contributes to the global warming as it forms acid in the ocean and it is a green house gas. In order to curb the green house gas emissions, in particular carbon dioxide, various multilateral agreements and programs have been established including UN Convention of Climate Change and its Kyoto Protocol for the last decades. Also a number of geo-engineering projects to manipulate the radiation balance of the earth have been proposed both from the science and industrial community worldwide. One of them is ocean fertilization to sequester carbon dioxide from the atmosphere through the photosynthesis of phytoplankton in the sea. Deliberate fertilization of the ocean with iron or nitrogen to large areas of the ocean has been proposed by commercial sector recently. Unfortunately the environmental consequences of the large scale ocean iron fertilization are not known and the current scientific information is still not sufcient to predict. In 2007, the joint meeting of parties of the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, 1972 and 1996 Protocol (London Convention/Protocol) has started considering the purposes and circumstances of proposed large-scale ocean iron fertilization operations and examined whether these activities are compatible with the aims of the Convention and Protocol and explore the need, and the potential mechanisms for regulation of such operations. The aim of this paper is to review the current development on the commercial ocean fertilization activities and management regimes in the potential ocean fertilization activities in the territorial sea, exclusive economic zone, and high seas, respectively, and further to have a view on the emerging international management regime to be London Convention/Protocol in conjunction with a support from the United Nations General Assembly through The United Nations Open-ended Informal Consultative Process on Oceans and the Law of the Sea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.262-268
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• 2017

The energy consumption of buildings is approximately 20.5% of the total energy consumption, and the interest in energy efficiency and low consumption of the building is increasing. Several studies have performed energy analysis and evaluation. Energy analysis and evaluation are effective when applied in the initial design phase. In the initial design phase, however, the energy performance is evaluated using general level information, such as glazing area and surface area. Therefore, the evaluation results of the detailed design stage, which is based on the drawings, including detailed information of the materials and facilities, will be different. Thus far, most studies have reported the analysis and evaluation at the detailed design stage, where detailed information about the materials installed in the building becomes clear. Therefore, it is possible to improve the accuracy of the energy environment analysis if the energy environment information generated during the life cycle of the building can be established and accurate information can be provided in the analysis at the initial design stage using a probability / statistical method. On the other hand, historical data on energy use has not been established in Korea. Therefore, this study performed energy environment analysis to construct the energy environment historical data. As a result of the research, information classification system, information model, and service model for acquiring and providing energy environment information that can be used for building lifecycle information of buildings are presented and used as the basic data. The results can be utilized in the historical data management system so that the reliability of analysis can be improved by supplementing the input information at the initial design stage. If the historical data is stacked, it can be used as learning data in methods, such as probability / statistics or artificial intelligence for energy environment analysis in the initial design stage.