• The Journal of Engineering Geology
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• v.10 no.2
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• pp.18-35
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• 2000

The most dominant type of landslide in Korea is debris flows which mostly take place along mountain slopes during the rainy season, July to August. The landslides have been reported to begin activation when rainfall is more than 200mm within 2days. The debris flows are usually followed by translational slips which occur upper part of mountain slopes and they transit to debris flow as getting down to the valleys. Lithology, location, slope inclination, grain size distribution of soil, permeability, dry density and porosity have been proved as triggering factor causing translational slides. The triggering data taken from mapping are statistically analysed to get landslide potential quantitatively. Rock mass creeps mostly occur on well bedded sedimentary rocks in Kyeongsang Basin. Although the displacement of rock mass creep is relatively small about 1m, the creep can cause severe hazards due to relatively large volume of the involved rock mass. Examples are rock mass creep occurred in the mouth of Hwangryongsan Tunnel, in Chilgok and in Sachon in 1999. Although the direct factor of the creeps are due to slope cutting at the foot area, more attention is required A rotational slide occurring within thick soil formation or weathered rock is also closely related to bottom part of slope cutting. It is propagated circular or semi-circular type. Especially in korea, the rotational slide may be frequently occurred in Tertiary tuff area. Because they are mainly composed of volcanic ash and pyroclastic materials, well developed joints and high degree of swelling and absorption can easily cause the slide. The landslide among the Pohang-Guryongpo national road is belong to this type of slide.

• Journal of Korean Society of Transportation
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• v.17 no.1
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• pp.173-185
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• 1999

The purpose of this study is to develope a forecasting model to implement short-term Congestion Management Program (CMP) based on TDM strategies in Seoul. The CMP is composed of three elements: 1) setting a goal of short-term traffic management. 2) developing a model to forecast the impacts of TDM alternatives, and 3) finding TDM measures to achieve the goal To Predict the impacts of TDM alternatives, a model called SECOMM (SEoul COngestion Management Model) is developed. The model assumes that trip generation and distribution are not changing in a short term, and that only mode split and traffic assignment are affected by TDM. The model includes the parameter values calibrated by a discrete mode choice model, and roadway and transit networks with 1,020 zones. As a TDM measure implement, it affects mode choice behavior first and then the speeds of roadway network. The chanced speed again affects the mode choice behavior and the roadway speeds. These steps continue until the network is equilibrated. The study recommends that CMP be introduced in Seoul, and that road way conditions be monitored regularly to secure the prediction accuracy of SECOMM. Also, TDM should be the major Policy tools in removing short-term congestion problems in a big city.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.276-289
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• 1998

Purpose: To evaluate dysphagia objectively and quantitatively, and to clarify the effect of neck position and viscosity changes in patients with aspiration and laryngeal penetration. Materials and Methods: We studied 35 patients with dysphagia and 21 normal controls using videofluoroscopy and scintigraphy. Videofluoroscopy was performed with barium with three different viscosity, and scintigraphy was done with water, yogurt, and steamed egg mixed with Tc-99m tin colloid. If aspiration was found during videofluoroscopic examination, patient's neck position was changed and study repeated. Videofluoroscopy was analyzed qualitatively. We calculated 7 quantitative parameters from scintigraphy. According to the videofluoroscopic findings, we divided patients into 3 subgroups; aspiration, laryngeal penetration, and no-aspiration group. Results: The result of videofluoroscopy revealed that the most common finding was the delay in triggering pharyngeal swallow. Pharyngeal transit time (PTT) and pharyngeal swallowing efficiency(PSE) in patients with aspiration were signifi-cantly different from other groups. After neck position change, aspiration could be reduced in all of 7 patients, and laryngeal penetration reduced by about 82%. PTT and PSE were also improved after position change. Aspiration and laryngeal penetration occurred more frequently in thin liquid swallowing than in thick liquid and solid swallowing. Conclusion: PTT and PSE were useful for the evaluation of dysphagia. Aspiration and laryngeal penetration could be reduced when appropriate position assumed. We could decrease the chance of aspiration by changing the patient diet consistency. Scintigraphy might be useful tool to quantitate and follow up these changes.

• Journal of Life Science
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• v.29 no.12
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• pp.1329-1336
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• 2019

Subventricular zone (SVZ) in the brain contains neural stem cells (NSCs) which self-renew and differentiate to neurons and glial cells during postnatal period and throughout adulthood. Since fate decision to either proliferation or differentiation has to respond to intracellular and extracellular conditions, many intrinsic and extrinsic factors are involved. Among them, mitochondria have been reported to participate in fate decision of NSCs. In our previous report, we showed that long-term treatment of a mitochondrial inhibitor rotenone greatly inhibited neurogenesis. In this study, we examined the effects of short-term treatment of rotenone on SVZ NSCs. We found that (1) even one-day treatment of rotenone significantly reduced neurogenesis and earlier time points seemed to be more sensitive to rotenone, (2) a number of Mash1+ transit amplifying cells was decreased by one-day treatment of rotenone, (3) short-term treatment of rotenone eliminated most of the differentiated Tuj1+ neurons and Olig2+ oligodendrocytes, while glial fibrillary acidic protein (GFAP)+ astrocytes were not affected, and (4) sulfiredoxin 1 (Srxn1) gene expression was increased after one-day treatment of rotenone, indicating activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. All these results confirm that functional mitochondria are necessary during differentiation to neurons or oligodendrocytes as well as maintenance of neurons after differentiation. Also, these data suggest that temporary exposure to mitochondrial inhibitor such as rotenone might have long-term effects on neurogenic potential of NSCs.

• Journal of Trauma and Injury
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• v.23 no.2
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• pp.75-82
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• 2010

Purpose: In Korea, trauma is the $3^{rd}$ most common cause of death. The trauma treatment system is divided into pre-hospital and hospital stages. Deaths occurring in the pre-hospital stage are 50% of the total death, and 20% of those are deaths that are preventable. Therefore, the purpose of our study is to calculate the preventable death rates caused by trauma in our current pre-hospital system, to analyze the appropriateness of the treatment of traumatized patients and to draw a conclusions about the problems we have. Methods: The study was done on traumatized patients who expired at the emergency department from January 1, 2005, to December 31, 2009, at the Korea University Medical Centers in Anam, Guro and Ansan. The data on the patients were reviewed retrospectively based on characteristics, conditions on admission and trauma severity. The patient's RTS (revised trauma score) and ISS (injury severity score) was calculated. Preventable death rate was calculated by TRISS (the trauma score-injury severity score). Results: A total of 168 patients were enrolled. All patients were intubated and underwent CPR. Of the total, 72% patients were male, and traffic accidents were the most common form of trauma (52.4%), falls being second (28.6%). Head injury, solitary or multiple, was the most common cause of death (55.4%). Thirty-eight (38, 22.6%) deaths were preventable. The 22.6% preventable death rate consisted of 15.5% potentially preventable and 7.1% definitely preventable deaths. Based on a logistic regression analysis, the relationship between the time intervals until transfusion and imaging and death was statistically significant in the hospital stage. In the pre-hospital stage, transit time from the site of the injury to the hospital showed a significant relationship with the mortality rate. Conclusion: One hundred sixty-eight (168) patients died of trauma at the 3 hospitals of Korea University Medical Center. The TRISS method was used to calculate the preventable death rate, with a result of 22.6%. The only factor that was significant related to the preventable death rate in the pre-hospital stage was the time from injury to hospital arrival, and the time intervals until transfusion and imaging were the two factors that showed significance in the hospital stage. Shortening the time of treatment in the field and transferring the patient to the hospital as quickly as possible is the most important life-saving step in the pre-hospital stage. In the hospital stage, the primary survey, resuscitation and diagnosis should proceed simultaneously.

• Journal of Korean Society of Transportation
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• v.35 no.6
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• pp.481-498
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• 2017

Travel time reduction benefit is the most important benefit item in the feasibility study of transportation infrastructure investment projects and calculated by using the value of travel time. The current feasibility study guideline (5th edition) calculate the value of non-business ravel time in a metropolitan area, using the ratio of the value of non-business travel time to business travel time calculated based on the nationwide inter-regional traffic survey data of 1999. The characteristics of metropolitan trips are different from those of nationwide regional trips. Metropolitan trips have frequent transfers between multiple public transits and long-time commuter trips. Therefore, this research aims to calculate the value of travel time reflecting traffic characteristics in a metropolitan area by improving the limitation of current calculation methods. To reflect these characteristics, this research extracts commuter trips from non-business trips and calculates the value of travel time for commuter trips. The results of the likelihood ratio test for the commuter trip model and the non-business trip model are found to be statistically significant. An integrated public transportation model was also estimated in this study to reflect the trip conditions of the Seoul metropolitan area integrated fare system. The results of comparing coefficients between bus and subway in the integrated public transit model indicated that there were no statistically significant differences between the two modes.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.6
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• pp.1701-1705
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• 2005

Dysphagia is Swallowing disorder characterized by difficulty in oral preparation for the swallow or in moving material from the mouth to the stomach. Dysphagia is the one of the most symptom of CVA and predisposes to medical complications such as aspiration pneumonia in poststroke patients. This study was designed to report the clinical effects of acupuncture for dysphagia on a patient with Wallenberg's syndrome. 8 acupoint were used and videofluoroscopic evaluation were performed. According to the above evaluation, 'Oral transit time' decreased within 1.5 sec and 'Coating of pharyngeal wall after swallow' were disappeared. The above results suggest that acupuncture is beneficial for dysphagia.

• Journal of the Korean Society of Radiology
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• v.6 no.1
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• pp.19-26
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• 2012

It is very important for early diagnosis and therapy with ischamic cerebral infarction patients. This study was to know the ischemic penumbra lesion which compared CT-perfusion and diffusion weighted MRI(DWMRI) with acute cerebral infarction patients. 12 acute cerebral infarction patients had performed perfusion CT and performed DWMRI. Perfusion images including cerebral blood volume(CBV), cerebral blood flow(CBF), time to peak(TTP) and mean transit time(MTT) maps obtained the values with defect lesion and contralateral normal cerebral hemisphere and DWMRI was measured by signal intensity and compared of lesion size between each perfusion map. All perfusion CT maps showed the perfusion defect lesions in all patients. There were remarkable TTP and MTT delay in perfusion defect lesions. The lesions on CBF map was the most closely correlated with the lesions on DWMRI. The size of perfusion defect lesions on TTP and MTT map was larger than that of lesions on DWMRI, suggesting that MTT map can evaluate the ischemic penumbra. Perfusion CT maps make it possible to evaluate not only ischemic core and ischemic penumbra, but also hemodynamic status in the perfusion defect area. These results demonstrate that perfusion CT can be useful to the diagnosis and treatment in the patients with acute cerebral ischemic infarction.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2008.04a
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• pp.5-20
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• 2008

GLP-1-based drugs (GLP-1 analogues and DPP IV inhibitors) and incretin mimetics are currently one of the most exciting classes of agents for type II diabetes. GLP-1, a gut peptide, is an incretin that potentiates glucose-dependent insulin release from the pancreas, slows GI-transit and stimulates the proliferation of beta-cells. DPP IV inhibitors act like incretins by inhibiting DPP IV which inactivates GLP-1. LC15-0133 is a competitive, reversible DPP IV inhibitor ($IC_{50}$ = 24 nM, Ki=0.247 nM) with excellent selectivity over other critical human proteases such as DPP II, DPP 8, elastase, trypsin. and urokinase. LC15-0133 showed long half-life and good bioavailability in rats and dogs. Inhibition of plasma DPP IV activity by LC15-0133 was kept more than 50% 24 hours after oral dosing in rats and dogs at 0.1 mg/kg and 0.02 mg/kg, respectively. The Minimum effective doses of LC15-0133 were 0.01 mg/kg for lowering blood glucose excursion during oral glucose tolerance test and 0.1 mg/kg for increasing glucose-induced GLP-1 response in C57BL/6 mice. Repeat oral administration of LC15-0133 for 1 month delayed the progression to diabetes and reduced HbA1c levels in a dose-dependent manner in Zucker Diabetic Fatty rats. In conclusion, LC15-0133 is a novel, potent, selective and orally active DPP IV inhibitor and showed an excellent blood glucose lowering effects in various animal models.

• Journal of the Korean Wood Science and Technology
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• v.34 no.1
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• pp.23-31
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• 2006

X-ray transit materials with straight path and the its intensity is proportional to the density of materials. Therefore, X-ray has been extensively used as a nondestructive evaluation (NDE) method in various fields. This study was carried out for development of a portable X-ray CT (computed-tomography) system to detect deteriorations of wood members in buildings. Based on the results of our previous study, a procedure of CT image reconstruction was established In order to verify the applicability of developed system, CT images of three wood disks were reconstructed by newly developed procedure and compared with the prototypes. From the results of this study, it was shown that the newly developed system could be used not only to determine the shape, size, and position of defects, but also to find the density distribution in cross section of wood structure members. The density distribution may be utilized to clarify the reason of wood deterioration and to provide the preventive method on how to treat or repair wood buildings. Because it was initial stage of system development, there were some limitations concerned with measuring equipment and image reconstruction algorithm. Especially, measuring time including equipment setup time was longer and measuring accuracy was lower than we expected. Therefore, we planned some additional studies on improvement of equipment and algorithm to enhance the capability of X-ray CT system.