• The Korean Journal of Nuclear Medicine
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• v.37 no.6
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• pp.393-401
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• 2003

Objective: Pullulan derivatives (PD) can be used to make self-assembled hydrogel nanoparticles which are responsive to ionic strength. The aim of this study is to evaluate the potential of PD as a retaining carrier of radioisotope inside tumors. Materials and Methods: Four types of PD were evaluated which included pullulan acetate (PA), succinylated PA (SPA), PA-DTPA and SPA-DTPA conjugates. They were radiolabeled with Tc-99m. Labelling efficiencies were determined at 30 min, 1, 2, 4 and 12 hours after radiolabeling. CT-25 colon cancer cells were subcutaneously injected into Balb/c mice. After 2 weeks of subcutaneous injection, Tc-99m-labelled PD (Tc-99m-PD) were injected into the tumors. Whole body images of mice were obtained at 30 min, 1, 2, and 12 hr after intratumoral injection. All twenty mice were grouped into four groups by largest diameter; control A (largest diameter = 5 mm, n = 5), control B (largest diameter = 10 mm, n = 5), pullulan A (largest diameter = 5 mm, n = 5), pllulan B (largest diameter = 10 mm, n = 5). Dynamic images were obtained for 1 hour after intratumoral injection. Static images were obtained at 1 hr, 2 hr, 3 hr and 4 hr after intratumoral injection with Tc-99m pertechnetate and Tc-99m-PA. Target-to-background ratios and retention rates were calculated. Results: Labeling efficiencies of PA, SPA, PA-DTPA and SPA-DTPA were $94.5{\pm}5.9%,\;97.8{\pm}3.5%\;94.2{\pm}3.8%,\;and\;92.5{\pm}6.2%$, respectively (p>0.05). Percent retention rates (%RR) of PA and PA-DTPA were significantly higher than those of control, however, those of SP-DTPA and SPA became similar to control at 4 and 12 hr, respectively. %RR of pullulan A and pullulan B at 1, 4 and 8 hr is significantly higher than that of control (p < 0.05). However, %RR between pullulan A and pullulan B were similar. Conclusion: The lonic strength dependent PD-nanoparticles are retained in the tumor. No difference of %RR according to tumor size was noted. Therapeutic application of PD labelled with beta- or alpha- emitting radionuclides can be expected.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.4
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• pp.317-323
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• 2018

When oral cancer develops in the maxilla, oro-nasal communication occurs after surgical treatment including removal of the primary site. Restoration through an obturator is necessary to prevent food from storing due to non-oral opening, and to ensure proper pronunciation and aesthetic restoration. In this case, the patient was treated with right hemi-maxillectomy due to oral cancer and has residual abutment and poor periodontal support due to the effect of head and neck radiotherapy. The obturator was treated with a hybrid telescopic double crown denture. Reporting a successful prognosis in 18 months of follow-up.

• Journal of the Korean Geographical Society
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• v.35 no.4
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• pp.641-647
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• 2000

한반도 중부지방의 사면형성과정을 검토하기 위하여 이 지역에 광범위하게 분포하는 쥬라기의 화강암과 선캄브리아기의 편마암으로 구성된 산지 소유역에서 수문관측을 실시하였다. 화강암 유역의 면적은 0.0546$\textrm{km}^2$이며, 기복비는 0.35이다. 편마암 유역은 다소 넓어 면적은 0.0754$\textrm{km}^2$이나 기복비는 0.36으로 거의 같다. 두 유역의 사면은 모두 사림으로 피복되어 있다. 관입시험 결과에 의하면 화강암유역 토층의 층후는 20cm 이하로 얇고 도처에 기반암이 보출된다. 반면에 편마암 유역의 층후는 50cm 이상으로 상대적으로 두껍게 나타난다. 관측은 1999년 5월부터 시작하였으며, 현재도 계속되고 있다. 강우에 대한 유출방응은 편마암 유역이 화강암 유역에 비하여 신속하게 나타난다. 첨두유량과 기저유량 모두 화강암유역보다는 편마암유역에 전반적으로 높게 관측되어 편마암 유역 사면에서의 저류량이 큰 것으로 생각된다. 또한 편마암사면에서 우수의 체류시간을 반영하여 전기전도도는 편마암 유역이 화강암유역보다 2배 정도 높게 관측된다.

• Tunnel and Underground Space
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• v.22 no.4
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• pp.266-275
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• 2012

In this study, a method is devised to implement a supercritical $CO_2$ ($scCO_2$) injection environment on a laboratory scale and to investigate the effects of $scCO_2$ on the properties of rock specimens. Specimens of shale and sandstone normally constituting the cap rock and reservoir rock, respectively, were kept in a laboratory reactor chamber with $scCO_2$ for two weeks. From this stage, a chemical reaction between rock surface and the $scCO_2$ was induced. The effect of saline water was also investigated by comparing three conditions ($scCO_2$-rock, $scCO_2-H_2O$-rock and $scCO_2$-brine(1M)-rock). Finally, we checked the changes in the properties before and after the reaction by destructive and nondestructive testing procedures. The swelling of shale was a main concern in this case. The experimental results suggested that $scCO_2$ has a greater effect on the swelling of the shale than pure water and brine. It was also observed that the largest swelling displacement of shale occurred after a reaction with the $H_2O-scCO_2$ solution. The results of a series of the destructive and nondestructive tests indicate that although each of the property changes of the rock differed depending on the reaction conditions, the $H_2O-scCO_2$ solution had the greatest effect. In this study, shale was highly sensitive to the reaction conditions. These results provide fundamental information pertaining to the stability of $CO_2$ storage sites due to physical and chemical reactions between the rocks in these sites and $scCO_2$.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.381-393
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• 2014

Seismic reflection data are integrated with fieldwork data in order to understand startigraphy, structural geology and hydrocarbon potentials of Cretaceous strata in the Mesopotamian basin, Northeastern Iraq. Cretaceous strata in the basin divided into the Qamchuqa, Kometan, Bekhme and Shiranish formations, which are composed of carbonates deposited in shallow marine environment. The geological structures in these formations are mainly recognized as thrusts, detachment folds, fault propagation folds and fault bend folds. As well, NW-SE trending fractures are regularly developed, and are horizontal or perpendicular to the structures. The distribution and frequency of fractures are related to the development of the thrusts. In terms of hydrocarbon potentials, Cretaceous strata in the basin have limited capacities for source rocks and seal rocks due to the lack of organic carbon content and the well-developed fractures, respectively. Although these carbonates have limited primary porosity, however, development of the secondary porosity derived from the fractures contributes to enhance the reservoir quality. Most important factor for the reservoir quality of Cretaceous strata seems to be the frequency and connectivity of fractures relative to locations of folds and faults. The results delineated in this study will use as reference for recognizing stratigraphy and structures of Cretaceous strata and will provide useful information on hydrocarbon potentials of Cretaceous strata in the Mesopotamian basin, NE Iraq.

• Journal of Soil and Groundwater Environment
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• v.10 no.6
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• pp.45-55
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• 2005

The geothermal research has been carried out on the Heunghae, Pohang geothermal area know as having geo-heat-flow area in the Korean peninsula. This study results so far indicate that geothermal water in the area is in peripheral waters of hydrothermal area and is not in equilibrium with the reservoir rock. The average oxygen and hydrogen stable isotope values are as follows: deep groundwater $(average:\;{\delta}^{18}O=-10.1\%_{\circ},\;{\delta}D=-65.8\%_{\circ})$, intermediate groundwater (average: $(average:\;{\delta}^{18}O=-8.9\%_{\circ},\;{\delta}D=-59.6\%_{\circ})$, shallow groundwater $(average:\;{\delta}^{18}O=-8.0\%_{\circ},\;{\delta}D=-53.6\%_{\circ})$, surface water $(average:\;{\delta}^{18}O=-7.9\%_{\circ},\;{\delta}D=-53.3\%_{\circ})$ respectively. Deep groundwaters was originated from a local meteoric water recharged from distant, topographically high mountain region and not affected by the sea water. High temperature zone inferred from water geothermometers is around D-1, D-5, D-6, 1-04 well zones. The estimated enthalpy from Silica-enthalpy mixing model is near 410 kJ/kg, which corresponds to the temperature of $98^{\circ}C$, and in consistent with the result of Na-K and K-Mg geothermometer.

• Geophysics and Geophysical Exploration
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• v.18 no.3
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• pp.125-132
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• 2015

The water saturation ($S_w$), which is very important to estimate hydrocarbon reserves in the reservoir, has been determined from resistivity index (RI) by using the Archie's formula. However, in many cases, it has been reported that n is not constant for a given formation and it could be varied with water saturation. In addition, it frequently happens that the line obtained by linear regression analysis on log-log scale does not pass through the origin. In order to overcome these drawbacks, we suggested a modified Archie's formula, which can handle almost all the RI vs. $S_w$ cross-plots whether the trend is straight or curved and whether it passes through the origin or not. We also demonstrated that how to determine conductivity exponent ${\mu}$, critical water saturation $S_c$, and saturation distribution factor b in the laboratory to use the modified Archie's formula. Since the modified Archie's formula takes into account pore structure, pore water distribution, and wettability of reservoir such as clean sandstone and carbonate rocks, it might improve field applicability.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.359-373
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• 2013

Shale is considered as a source rock for conventional oil and gas exploration and development because shale is fine-grained detrital sedimentary rock which can preserve the organic matter better. Shale has a good sealing capacity for the petroleum trap due to its low permeability. Commercial recoveries of gas from shale in the North America based on the development of technologies of horizontal drilling and hydraulic fracturing reveal that shale also function as a effective reservoir rock. Geochemical techniques to evaluate generation potential of the hydrocarbons from organic matter in the source rocks can be applied for the exploration of the shale gas resources. To evaluate shale gas resources, it is important to understand various geochemical processes and shale characteristics controlling generation, storage and estimation of shale gas reserves. In this paper, the generation mechanism of the oil and gas from organic matter is reviewed, and geochemical techniques which can be applied for the evaluation and characterization of shale gas are introduced.

• Journal of Life Science
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• v.30 no.6
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• pp.563-569
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• 2020

Oncoplastic surgery (OPS) combines oncologically safe tumor resection with aesthetically satisfying reconstruction of defects using established plastic surgery techniques. OPS is characterized by initial excision as extensive as is beneficial for oncological safety, and, once sufficient resection is complete, displacement or replacement techniques are selected based on remnant volume. The size of the lesion and the individual patient are important factors when considering the appropriate approach, and when pre-operative imaging, including MRI, is used to determine the technique, the complete removal of cancer cells by permanent pathology is essential. A frozen section is used during the operation to reduce the reoperation rate, but it is difficult to cover the entire margin surface theoretically and even harder in practice. A recent report about adequate margins has empowered OPS in its oncological safety. Considering the patients to whom each modality could be applied, basic breast volume is an important factor, and this is influenced by ethnic differences. In Europe or the US, for example, the average breast size is 36D (600 ㎤) and reduction mammoplasty is predominantly used. However, the average size of patients in our institution is 33A (300 ㎤), and so quite different approaches are selected in most cases. New techniques involving radiofrequency and fluorescence have been proposed as safe and easily accessible ways of reducing complications.

• The Journal of Engineering Geology
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• v.31 no.1
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• pp.1-17
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• 2021

It is important to evaluate the fracture network in a rock volume because fractures control the ground conditions and fluid flow characteristics. Therefore, various attempts have been made to quantify fracture networks to better understand ground and flow conditions. The use of fracture density alone (a quantitative parameter based on geometric analysis) does not fully explain the evolution of fracture networks, or quantify the spatial relationship (e.g. connectivity) of fractures in a rock mass. Therefore, the need for fracture network characterization based on topological analysis has recently emerged. In Korea however, the topological analysis of fracture networks within a rock mass has rarely been studied. As such, the definition of the topological analysis of fracture networks and the graph theory related to the topological analysis are briefly summarized in this study. We also introduce an application method for these analyses to fracture characterization. If the topological method is used for the analysis of fracture networks, it can also be adopted to analyze fluid flow characteristics of groundwater, characterize petroleum reservoirs, and analyze the evolution of a fracture network. In addition, topological analysis can be useful for site selection of major facilities such as nuclear waste disposal sites because it can be used to evaluate the stability of the potential sites.