• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.1
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• pp.53-62
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• 1987

High power lasers provide a controllable and precise energy source in surface transformation hardening. A careful control of the process is needed in order that the surface layer of the material reaches the austenizing temperature, but that it does not melt. In order to achieve this the results of theoretical and experimental studies on the laser surface hardening of a medium carbon steel are described. A two-dimensional computer program, which can be used generally for the determination of transient temperature distributions in welding and heat treatment, was established on the basis of the finite element method. For the confirmation of the accuracy of the numerical analysis, a medium carbon steel (SM 45C) of 5mm thickness was heat-treated with a 1kW CW CO$_{2}$ laser machine, while the traverse speed and the distance from the focal point (defocused distance) were varied. Experimental and numerical results showed a similar tendency in correlations between the hardened zone shape and the process parameters. With increasing beam spot diameter the width and depth of the hardened zone increased for relatively small beam spot diameters, but decreased rapidly after reaching the maximum value, while with increasing traverse speed the width and depth of the hardened zone decreased monotonously. Too small beam spot diameters are to be avoided, since the surface melting would lower the surface hardness and produce an uneven surface which may be unacceptable because of the possible requirement for subsequent machining. It could be observed that for a given traverse speed and laser power input there exists a optimal range of the beam spot diameter, which produce a large width of the hardened zone but no melting on the surface.

• Journal of Food Hygiene and Safety
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• v.12 no.2
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• pp.141-152
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• 1997

This study was performed to investigate the toxic effect of pyrrolizidine alkaloids from symphytum officinale i n rat. For this experiment, 120 male and female rats of Sprague-Dawley strain were used. The experimental groups were divided into five: Group CM and CF served as normal control with its gender. Group EM1 and EF1 were fed a 1% Symphytum officinal extract diet for 8 weeks. Group EM2 and EF2 fed a diet containing 2% extract diet. 4% extract diet into group EM3 and EF3 and 8% extract diet into group EM4 and EF4 were given. The results were as follows: 1. The major alkaloids of Symphytum officinale extract were symphytine, echmidine, and lasiocarpine. The amounts of total alkaloid were 168 $\mu\textrm{g}$ PAs/$m\ell$ extract. And contents of Pas in leaves were 0.05% wt.. 2. Total serum bilirubin concentrations increased significantly in group EM2, EM3, and EM4. Group EF1, EF2, EF3, and EF4 showed statistical significance for the group CF (p<0.05). 3. Aspartate transaminase activities were increased significantly in group EM3 and EM4 (p<0.05). Aspartate transaminase activities of EF1, EF2, EF3, and EF4 showed statistical significance for the group CF (p<0.05). 4. Alanine transaminase activities increased significantly in group EM3, EM4 (p<0.05). Alanine transaminase activities of EF1, EF2, EF3, and EF4 showed statistical significance for the group CF (p<0.05). 5. Alkaline phosphatase activities increased significantly in group EM2, EM3, and EM4 (p<0.05). Alkaline phosphatase activities of EF1, FE@, EF3, and EF4 showed statistical sigmificance for the group CF (p<0.05). 6. istopathological analysis of liver specimens from group EM3 and EM4 showed focal necrosis, periportal necrosis and apoptpsis. Hepatocytes obtained from group EM2 showed fatty change and hydropic degeneration in group EM3 and EM4. Chromatolysis and chromatin margination was shown in group EF2 and EF3. With the above results, it was demonstrated that the Symphytum officinal extract could induce functional change of liver, and histopathological change of liver in rats fed a diet containing extract. In conclusion, because of the risk of intoxication or adverse effect, the composition, dosage and mode of administration of herbal products should be monitored strictly. And this study serves as a reminder that herbal as well as orthodox medications may have serious side effects.

• Childhood Kidney Diseases
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• v.19 no.2
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• pp.98-104
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• 2015

Objective: To find out clinical features and long-term outcomes of idiopathic childhood nephrotic syndrome(NS) patients with late steroid resistance(LSR)/late steroid sensitiveness(LSS). Patients and Methods: A retrospective chart review was performed on 480 patients diagnosed with idiopathic childhood NS at Asan Medical Center Children's Hospital from 1990 to 2013. Twenty-four patients whose responsiveness to steroids changed over a minimum 2 year follow-up period (2-17.5 years) were investigated. All patients had undergone a renal biopsy. Results: Among 480 nephrotic children, 428 (89%) were sensitive to the first steroid course. Of those who initially responded, 11 (2.5%) developed resistance to steroid therapy after relapses. LSR mostly developed between 1 month and 1 year after the initial episode. Six patients showed a minimal change and five showed focal segmental glomerulosclerosis (FSGS). Nine (82%) responded to cyclosporine or methylprednisolone pulse therapy. Of these, two had no further relapse, whereas the other seven experienced several relapses that ranged in length from 1.1 to 13.9 years. Three of the nine who initially responded to immunosuppression went on to experience several changes in steroid responsiveness. Two (18%) with resistance to immunosuppressants, including steroids, eventually progressed to end stage renal disease. Among the 52 patients (11%) who were initially steroid resistant, 13 (23%) were converted to steroid sensitive at relapses. Among these, 9 showed minimal change and 4 showed FSGS. Two had no further relapse and the other 11 responded to steroids on subsequent relapses ranging in length from 1.3 to 9.4 years. All these patients have had no further changes in steroid responsiveness with normal renal function. Conclusions: In this study, 2.5% of initial steroid responders and 25% of initial steroid non-responders changed their responsiveness to steroids at subsequent relapses. Eighteen percent of LSR patients developed end stage renal disease. All of the LSS patients showed preserved normal renal function. Responsiveness to immunosuppressants seemed to be the most important factor determining longterm outcomes in LSR/LSS patients.

• Journal of Veterinary Clinics
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• v.32 no.5
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• pp.459-463
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• 2015

A 14-year-old, castrated male mixed-breed dog weighing 9 kg was presented for hematuria and dysuria. Abdominal ultrasound showed unilateral hydronephrosis and hydroureter with focal thickening of the ureteral wall. Surgical exploration revealed an intraluminal mass arising from the proximal left ureter. Mass resection was performed. Histopathology of the ureteral mass was consistent with a papillary transitional cell carcinoma. The patient recovered well post-operatively, but was diagnosed with another tumor three months later, this time in the right kidney. Fine-needle aspiration cytology of the renal mass revealed an epithelial cell tumor with mesenchymal features.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.187-197
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• 2010

The paleoseismological study in Korea has begun along the Yangsan fault zone (YFZ) and Ulsan fault zone (UFZ) since 1994. Some evidences related to late Quaternary movement are found at only some part of the YFZ, such as Pyonghae, Yuge, and Eonyang-Tongdosa areas. However, it is found along the most of the UFZ except the northen and southern ends of the fault. The dominant time span of faulting events along the YFZ and UFZ are quite different, and 500 ka to 200 ka and 300 ka to recent time, respectively. The dominant faulting senses of the YFZ and UFZ are right-lateral strike slip and reverse, respectively. These senses correspond well with the focal mechanism of recent occurring earthquakes along these two fault zones. If we evaluate the intensity of the activity of the YFZ from the average slip rate, which is 0.1~0.04 m/ka, it is comparable with the faults of higher C class in Japan. The slip rate of UFZ, which is 0.2~0.06 m/ka, is comparable with the faults of lower B to higher C class. Based on the relationship between maximum displacement and magnitude, the maximum earthquake magnitude is evaluated to be 6.8 and 7.0 in the YFZ and UFZ, respectively. An intensive studies are needed to clarify the problems such as segmentation of faults, return period, and geological evidences related to historical earthquakes.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.235-242
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• 2010

Two moderate earthquakes with local magnitude 4.9 and 5.0 at the Yellow Sea area occurred successively around Hong island on March 22, 2003 and Baengnyeong island on March 30, 2003, respectively, close to the Korean Peninsula. Focal mechanisms by the waveform inversion analysis are strike slip faulting with a thrust component for the March 22 event, and normal faulting for the March 30 event. The direction of P-axes of two events were ENE-WSW which were similar to previous studies on that of P-axes in and around the Korean Peninsula. Moment magnitudes determined by the waveform inversion analysis were 4.7 and 4.5, respectively, whereas those determined by spectral analysis were 4.8 and 4.6, respectively. As regards the March 22 event, regional stress by combined tectonic forces from compressions of plates colliding to the Eurasian plate, rather than mere local stress, was indicated. However, it was estimated that the March 30 event took place when the weak zone generated from the existing collision zone was reactivated when subjected to local stress in the tensile direction. This seismological observation indirectly supports the idea that the collision zone may extend to the Korean Peninsula.

• Proceedings of the Microbiological Society of Korea Conference
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• 2004.05a
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• pp.141-146
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• 2004

SPIN90 was identified to farm molecular complex with $\betaPIX$, WASP and Nck. This complex shows that SPIN90 interacts with Nck in a manner dependent upon cell adhesion to extracellular matrix, but $SPIN90{\cdot}{\beta}PIX{\cdot}WASP$ complex was stable even in suspended cells. This suggests that SPIN90 serves as an adaptor molecule to recruit other proteins to Nck at focal adhesions. SPIN90 was phosphorylated by ERK1, which was, itself, activated by cell adhesion and platelet-derived growth factor. Such phosphorylation of SPIN90 likely promotes the interaction of the $SPIN90{\cdot}{\beta}PIX{\cdot}WASP$ complex and Nck. It thus appears that the interaction of the $SPIN90{\cdot}{\beta}PIX{\cdot}WASP$ complex with Nck is crucial for stable cell adhesion and can be dynamically modulated by SPIN90 phosphorylation that is dependent on cell adhesion and ERX activation. SPIN90 directly binds syndapin I, syndapin isoform II-1 and II-s via its PRD region in vitro, in vivo and also associates with endocytosis core components such as clathrin and dynamin. In neuron and fibroblast, SPIN90 colocalizes with syndapins as puntate form, consistent with a role for SPIN90 in clathrin-mediated endocytosis pathway. Overexpression of SPIN90 N-term inhibits receptor-mediated endocytosis. Interestingly, SPIN90 PRD, binding interface of syndapin, significantly blocks internalization of transferrin, demonstrating SPIN90 involvement in endocytosis in vivo by interacting syndapin. Depletion of endogenous SPIN90 by introducing $\alpha-SPIN90$ also blocks receptor-mediated endocytosis. Actin polymerization could generate farce facilitating the pinch-out event in endocytosis, detach newly formed endocytic vesicle from the plasma membrane or push out them via the cytosol on actin tails. Here we found that SPIN90 localizes to high actin turn over cortical area, actin-membrane interface and membrane ruffle in PDGF treated cells. Overexpression of SPIN90 has an effect on cortical actin rearrangement as filopodia induction and it is mediated by the Arp2/3 complex at cell periphery. Consistent with a role in actin organization, CFP-SPIN90 present in actin comet tail generated by PIP5 $kinase\gamma$ overexpression. Therefore this study suggests that SPIN90 is functional linker between endocytosis and actin cytoskeleton.

• Toxicological Research
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• v.25 no.3
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• pp.140-146
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• 2009

This study was performed to evaluate the toxicity of cadmium selenide for a period of 28 days in Sprague-Dawley rats. Each of 10 healthy male and females rats per group received daily oral administration for 28-day period at dosage levels 30, 300 and 1,000 mg/kg of body weight. Mortality and clinical signs were checked, and body weight, water intake and food consumption were also recorded weekly. There were no dose-related changes in food consumption or urine volume. All animals survived to the end of study with no clinical signs or differences in body weight gain observed when compared with the control group. At the end of study, all animals including control group, were subjected to necropsy. Blood samples were collected for hematology tests including coagulation time and biochemistry analysis. Blood coagulation time and relative organ weight were unaffected by all received doses. White Blood Cell (WBC) counts significantly increased in the 300 mg/kg administered male animal group when compared to the control. Monocyte (MO) value were also increased significantly in both 300 and 1,000 mg/kg male animal group. However, Mean Corpuscular Volume (MCV) were significantly decreased compared with the control in the 1,000 mg/kg dose groups for male and female animals. Mean Corpuscular Hemoglobin (MCH) decreased significantly for female in the 300 and 1,000 mg/kg group compared to the control. Blood biochemical values of Inorganic phosphorus (IP) were significantly increased in both the 300 and 1,000 mg/kg dose groups in male animals when compared to the control. Creatinine (CRE) levels indicated significant increase in kidney function for the female, 30 mg/kg dose group when compared with control. There was a significant decrease in thymus absolute organ weight in the female, 1,000 mg/kg dose group when compared with control. Histopathological findings revealed no evidence of injury related to cadmium selenide except for one case of focal hepatic inflammation in the high dose (1,000 mg/kg) group. One case of lung inflammation was also seen in the control group. Basis on these result, the No Observable Adverse Effect Level (NOAEL) of cadmium selenide was determined to be more than 1,000 mg/kg/day for male and female rats under conditions in this study.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.240-248
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• 2005

To implement a globally harmonized system of classification and labeling of chemicals (GHS) in Korea, an interminsterial GHS working group involving 6 ministries established an expert working group composed of 7 experts from relevant organizations and one private consultant to prepare an officialKorean GHS version by March, 2005. As such, the translation and review of the official Korean GHS version, including annexes, started in October, 2004 and was completed on March 15, 2005. The official Korean GHS version has now been posted on the websites of the relevant ministries and organizations to solicit public opinions. The official Korean GHS version will be finalized after a public hearing scheduled forMay, 2005. Collaborative efforts as regards implementing and disseminating the GHS in Korea will be continued to avoid any confusion or duplication and for effective use of resources. The globally harmonized system of classifying and labeling chemicals (GHS) was originally adopted in 1992 at the United Nations Conference on Environment and Development (UNCED), as subsequently reflected in Agenda 21 chapter 19. The work was coordinated and managed under the auspices of the Interorganization Programme for the Sound Management of Chemicals(IOMC) Coordinating Group for the Harmonization of Chemical Classification Systems (UNCEGHS). The technical focal points for completing the work were the International Labour Organization (ILO); Organization for Economic Cooperation and Development (OECD); and United Nations Economic and Social Council's Subcommittee of Experts on the Transport of Dangerous Goods (UNSCETDG). The work was finalized in October 2002, and the World Summit on Sustainable Development in Johannesburg on 4 September 2002 encouraged countries to implement the new GHS as soon as possible with a view to having the system fully operational by 2008 (UN, 2003). Implementation has already started with pilot countries introducing the system to their national practices in different regions of the world. The GHS text, called the purple book, becameavailable as a W publication in early 2003. The GHS text, called the purple book, becameavailable as a UN publication in early 2003. The GHS system will be kept dynamic, and regularly revised and made more efficient as experience is gained in its implementation. While national or regional governments are the primary audiences for this document, it also contains sufficient context and guidance for those in industry who will ultimately be implementing the national requirements that will be introduced (UN, 2003). The Japanese government published their official Japanese GHS version, the first in Asia, in April 2004 after starting work in January 2003 based on an interministerial chemical coordination committee involving 7 ministries, including the Ministry of Foreign Affairs, Ministry of Internal Affairs and Communications, Ministry of Health, Labour, and Welfare, Ministry of Agriculture, Forestry and Fisheries, Ministry of Economy, Trade and Industry, Ministry of Land, Infrastructure, and Transport, and Ministry of Environment (MOE, 2004). Accordingly, similar to the Japanese GHS efforts, this paper presents the interministerial efforts involved in publishing the official Korean GHS version.

• Journal of Korean Neurosurgical Society
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• v.30 no.4
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• pp.522-527
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• 2001

We present a case of recurrent extraventricular neurocytoma with malignant glial differentiation in left temporoparietal area. A 37-year-old man with presentation of generalized seizure had undergone biopsy of brain tumor in left parietal area in 1987, which revealed extraventricular neurocytoma and radiotherapy was followed. Postoperative course was uneventful until eleven years after biopsy, when he became gradually aphasic and right hemiplegic. Brain CT and MRI revealed enlargement of tumor with peritumoral edema and calcifications. He underwent subtotal tumor removal in 1998. Microscopic examination of second biopsy specimen revealed presence of large areas composed of anaplastic glial cells with frequent mitosis, nuclear pleomorphism, large eosinophilic cytoplasm and eccentric nuclei, resembling gemistocytes, which were strongly immunoreactive to glial fibrillary acidic protein(GFAP) but not to synaptophysin(SNP). Also focal areas of neuronal cells were found, which were immunoreactive to SNP but not to GFAP. These histologic findings imply that this recurred tumor was a high grade, mixed tumor with divergent differentiation of neuronal and astrocyte lineage. We report a rare case of extraventricular cerebral neurocytoma with malignant glial differentiation with review of the literature.