• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.307-317
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• 1999

The purpose of this study is to utilize conventional procedures for evaluation of liquefaction potential and to compare the results obtained by modified detailed method based on Korean earthquake magnitude (M=6.5). Liquefaction potential is assessed by comparing liquefaction strength of soil and cyclic shear stress generated in the soil layers during earthquakes. The cyclic shear stress is computed from the earthquake response analysis, and liquefaction strength of soil is evaluated by using results from cyclic triaxial tests. The cyclic triaxial tests are performed on many different conditions of sample ; relative densities(50%, 60%, and 70%), initial effective confining pressures (70kPa, 100kPa, and 150kPa), and fine contents(10%, 20%, and 30%). From the result of comparing the conventional procedure with the modified detailed method, it is found that the modified detailed method tends to evaluate larger safety factor against liquefaction in the weak sand site$(FS \leq1.5)$. Therefore in this case, it is suggested that liquefaction potential should be evaluated by using the modified detailed method based on cyclic triaxial tests. It is also found that in modified detailed method based on earthquake magnitude 6.5, critical depth where liquefaction can be generated is around 15m from the ground surface.

• Tuberculosis and Respiratory Diseases
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• v.57 no.5
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• pp.443-448
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• 2004

Background : Small-cell carcinomas of lung have a tendency for rapid growth and early wide metastasis. Despite the high response rates of combination chemotherapy alone or with radiotherapy, the overall long-term survival rate is very disappointing. According to autopsy findings, the common cause of failure is local recurrence in the primary cancer site. Therefore, surgical resection with combined chemotherapy has recently been attempted for very early stage small-cell carcinomas of the lung. Methods : 10 patients (TNM I & II: 5 cases each) undergoing surgical resection for small-cell carcinomas of the lung were treated with adjuvant chemotherapy in an attempt to prolong survival. Of these, 9 patients received chemotherapy, and a retrospective study for survival undertaken (Kaplan-Meier analysis). Results : The median survival time was 26 months, and the 2- and 5-year survival rates were 68.6 and 46.7%, respectively. If the 1 patient not having undergone chemotherapy was excluded, the 2-, 5-year survival rates were 76.2 and 50.8%, respectively? No difference in the survival rate was seen between patients with TNM stages I and II. Conclusion : Adjuvant chemotherapy after surgical resection results in prolonged survival for patients with TNM stages I and II small-cell carcinomas of the lung.

• Journal of the Korean Geotechnical Society
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• v.30 no.10
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• pp.67-80
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• 2014

The thickness of permafrost in Eastern Siberia is from 200 to 500 meters. The seasonally frozen layer can vary from 0 to 4m depending on ground temperature and its location. The shear wave velocity varies from 80m/s in summer to 1500m/s in winter depending on soil type. When melted, large impedence will occur due to the difference between the shear wave velocity of seasonally frozen soil and that of permafrost layer. Large displacement may occur at the boundary of the melted and the frozen layer, and this phenomenon should be considered in a seismic design. In this research, one-dimensional equivalent linear analyses were performed to investigate the effects of the seasonally frozen layer on ground amplification characteristics. Soil profiles of Yakutsk and Chara in Eastern Siberia were selected from geotechnical reports. 20 recorded ground motions were used to evaluate the effect of input motions. As the thickness of seasonally frozen layer and the difference in the shear wave velocity increases, the amplification is shown to increase. Peat, very soft organic soil widely distributed throughout Eastern Siberia, is shown to cause significant ground motion amplification. It is therefore recommended to account for its influence on propagated motion.

• Journal of the Korean Geotechnical Society
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• v.18 no.1
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• pp.91-99
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• 2002

In this study, a new methodology for the assessment of liquefaction potential is proposed. Since there is no data on the liquefaction damage in Korea, the dynamic behavior of fully saturated soils is characterized through laboratory dynamic tests. There are two experimental parameters related to the soil liquefaction resistance characteristics : the one is the index of disturbance determined by $G/G_{max}$ curve and the other is a plastic shear strain trajectory evaluated from stress-strain curve. The proposed methodology takes advantage of the site response analysis based on real earthquake records to determine the driving effect of earthquake. In the evaluation of liquefaction resistance characteristics, it is verified experimentally that the magnitude of cyclic shear stress has no influence on the critical value of plastic shear strain trajectory at which the initial liquefaction occurs. Cyclic triaxial tests under the conditions of various cyclic stress ratios and torsional shear tests are carried out far the purpose of verification. Through this study, the critical value at the initial liquefaction is found unique regardless of the cyclic stress ratio. It is also f3und that liquefaction resistance curve drawn with disturbance and plastic shear strain trajectory can simulate the behavior of fully saturated soils under dynamic loads.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.73-82
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• 1989

When the flood occurs in the alluvial rivers, the rivers adjust to the flood by means of the mechanism of the river bed variations and its morphological changes to pass that safely, the numerical model was developed to simulate the process of the alluvial river bed variation due to flood wave and carried out by the flood routing for flood wave and the sediment routing for river bed variation. The flood wave, river bed variation, and bed material size distribution may be analysed and predicted by this model. The ability of this model to predict the process of river bed response was proved by the application to the reach from Paldang dam to Indogyo site. In view of the flood analysis considering the sediment process, the effects of river bed variation for the flood routing may be negligible because the river bed variation is smaller than the unsteady flow variation during the same period. By the application of this model, it is shown that, in occurring of sequential flood events, the variation of the river bed and bed material size distribution due to flood wave is more dependent on the first flood event than the latter flood events, and that the river bed variation in this reach of the downstream Han river is dependent on the degradation and the coarsening of bed materials.

• Radiation Oncology Journal
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• v.8 no.2
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• pp.177-182
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• 1990

From 1984 to 1988, fourty two patients with nasopharyngeal cancer were treated at the Department of Radiation Oncology in Kyungpook National University Hospital. Thirteen patients refused treatment and the median survival time was 7.8 months. Twenty nine patients received a full course of radiation at least 70 Gy to the primary site and 60 Gy to the nodal sites. These patients were all belonged to stage III or IV, The local control rate was $75\% in squamous cell carcinomas, and all the patients with lymphoepithelioma showed a complete response. Overall locoregional failure was $27.6\%. Distant metastasis was the predominant pattern of failures; 4/6 in lymphoepithelioma, 4/10 En squamous cell carcinoma. The Three-year-survival rate for squamous cell carcinoma was $40.5\%$, and for lymphoepithelioma $25.9\%, respectively. This may be due to the more frequent distant metastases in lymphoepithelioma and ineffective chemotherapy. No survival correlation was found with the level of neck node involvement. Though adjuvant chemotherapy was found to be of no benefit in overall survival, more prudent and aggressive chemotherapy would be necessary.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.221-237
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• 2005

For developing the site-specific fertilizer management strategies of crop, it is essential to know the spatial variability of soil factors and to assess their influence on the variability of crop growth and yield. In 2002 and 2003 cropping seasons within-field spatial variability of rice growth and yield was examined in relation to spatial variation of soil properties in the· two paddy fields having each area of ca. $6,600m^2$ in Suwon, Korea. The fields were managed without fertilizer or with uniform application of N, P, and K fertilizer under direct-seeded and transplanted rice. Stable soil properties such as content of clay (Clay), total nitrogen (TN), organic mater (OM), silica (Si), cation exchange capacity (CEC), and rice growth and yield were measured in each grid of $10\times10m$. The two fields showed quite similar spatial variation in soil properties, showing the smallest coefficient of variation (CV) in Clay $(7.6\%)$ and the largest in Si $(21.4\%)$. The CV of plant growth parameters measured at panicle initiation (PIS) and heading stage (HD) ranged from 6 to $38\%$, and that of rice yield ranged from 11 to $21\%$. CEC, OM, TN, and available Si showed significant correlations with rice growth and yield. Multiple linear regression model with stepwise procedure selected independent variables of N fertilizer level, climate condition and soil properties, explaining as much as $76\%$ of yield variability, of which $21.6\%$ is ascribed to soil properties. Among the soil properties, the most important soil factors causing yield spatial variability was OM, followed by Si, TN, and CEC. Boundary line response of rice yield to soil properties was represented well by Mitcherich equation (negative exponential equation) that was used to quantify the influence of soil properties on rice yield, and then the Law of the Minimum was used to identify the soil limiting factor for each grid. This boundary line approach using five stable soil properties as limiting factor explained an average of about $50\%$ of the spatial yield variability. Although the determination coefficient was not very high, an advantage of the method was that it identified clearly which soil parameter was yield limiting factor and where it was distributed in the field.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.4
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• pp.291-297
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• 2013

Notch1 has been reported to be highly expressed in triple-negative and other subtypes of breast cancer. Mutant p53 (R280K) is overexpressed in MDA-MB-231 triple-negative human breast cancer cells. The present study aimed to determine whether the mutant p53 can be a potent transcriptional activator of the Notch1 in MDA-MB-231 cells, and explore the role of this mutant p53-Notch1 axis in curcumin-induced apoptosis. We found that curcumin treatment resulted in an induction of apoptosis in MDA-MB-231 cells, together with downregulation of Notch1 and its downstream target, Hes1. This reduction in Notch1 expression was determined to be due to the decreased activity of endogenous mutant p53. We confirmed the suppressive effect of curcumin on Notch1 transcription by performing a Notch1 promoter-driven reporter assay and identified a putative p53-binding site in the Notch1 promoter by EMSA and chromatin immunoprecipitation analysis. Overexpression of mutant p53 increased Notch1 promoter activity, whereas knockdown of mutant p53 by small interfering RNA suppressed Notch1 expression, leading to the induction of cellular apoptosis. Moreover, curcumin-induced apoptosis was further enhanced by the knockdown of Notch1 or mutant p53, but it was decreased by the overexpression of active Notch1. Taken together, our results demonstrate, for the first time, that Notch1 is a transcriptional target of mutant p53 in breast cancer cells and suggest that the targeting of mutant p53 and/or Notch1 may be combined with a chemotherapeutic strategy to improve the response of breast cancer cells to curcumin.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.604-609
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• 2020

The purpose of this study is to check the priority control status of the current operation process alarm by comparing the priority of the alarm set up in PV high trip point, which is being installed and operated in the domestic petrochemical industry, with the criteria presented in ISA 18.2 International Standard or EEMUA 191 Guidelines. In the event of a process problem, excessively set high alarm is provided to the driver in a short period of time, making it difficult to identify the alarm that needs to be handled first. As a result, it is likely that the operator will not be able to carry out appropriate actions within the specified time frame, and many cases have been reported leading to unexpected process shutdowns or process accidents. Therefore, this study aims to introduce international standards related to alarm management and identify the level of alarm control used at the domestic petrochemical industry site to inform potential risks that may occur in the petrochemical process of the national industrial complex in the future and suggest ways to reduce risk factors. This paper was submitted to Professor Lee Inbeom's retirement anniversary issue.

• Journal of The Korean Dental Society of Anesthesiology
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• v.14 no.3
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• pp.157-165
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• 2014

Background: Incisional site of surgical operation become transient ischemic state and then occur reoxygenation due to vasodilatation by inflammatory reaction, the productive reactive oxygen species (ROS) give rise to many physiologic results. Apoptosis have major role on elimination of inflammatory cell and formation of granulation tissue in normal wound healing process. Remifentanil can prevent the inflammatory response and can suppress inducible nitric oxide synthase expression in a septic mouse model. After cardiopulmonary bypass for coronary artery surgery, remifentanil can also inhibit the release of biomarkers of myocardial damage. Here we investigated whether remifentanil pretreatment has cellular protective effect against hypoxia-reoxygenation in HaCaT human keratinocytes, if so, the role of apoptosis and autophagy on this phenomenon. Methods: The HaCaT human keratinocytes were exposed to various concentrations of remifentanil (0.01, 0.05, 0.1, 0.5 and 1 ng/ml) for 2 h before hypoxia (RPC/HR group). These cells were cultured under 1% oxygen tension for 24h at $37^{\circ}C$. After hypoxia, to simulate reoxygenation and recovery, the cells were reoxygenated for 12 h at $37^{\circ}C$. 3-MA/RPC/HR group was treated 3-methyladenine (3-MA), autophagy inhibitor for 1h before remifentanil treatment. Cell viability was measured using a quantitative colorimetric assay with thiazolyl blue tetrazoliumbromide (MTT, amresco), showing the mitochondrial activity of living cells. To investigate whether the occurrence of autophagy and apoptosis, we used fluorescence microscopy and Western blot analysis. Results: The viability against hypoxia-reoxygenation injury in remifentanil preconditioning keratinocytes were increased, and these cells were showed stimulated expression of autophagy 3-MA suppressed the induction of autophagy effectively and the protective effects on apoptosis. Atg5, Beclin-1, LC3-II and p62 were elevated in RPC/HR group. But they were decreased when autophagy was suppressed by 3-MA. Conclusions: Remifentanil preconditioning showed the protective effect in human keratinocytes, and we concluded that autophagy may take the major role in the recovery of wound from hypoxia-reoxygenation injury. We suggest that further research is needed about the cell protective effects of autophagy.