• The Journal of Engineering Geology
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• v.23 no.4
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• pp.447-455
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• 2013

A micro-mechanical pipe network model with the shape of a cube was developed to simulate the behavior of fluid flow through a porous medium. The fluid-flow mechanism through the cubic pipe network channels was defined mainly by introducing a well-known percolation theory (Stauffer and Aharony, 1994). A non-uniform flow generally appeared because all of the pipe diameters were allocated individually in a stochastic manner based on a given pore-size distribution curve and porosity. Fluid was supplied to one surface of the pipe network under a certain driving pressure head and allowed to percolate through the pipe networks. A percolation condition defined by capillary pressure with respect to each pipe diameter was applied first to all of the network pipes. That is, depending on pipe diameter, the fluid may or may not penetrate a specific pipe. Once pore pressures had reached equilibrium and steady-state flow had been attained throughout the network system, Darcy's law was used to compute the resultant permeability. This study investigated the sensitivity of network size to permeability calculations in order to find out the optimum network size which would be used for all the network modelling in this study. Mean pore size and pore size distribution curve obtained from field are used to define each of pipe sizes as being representative of actual oil sites. The calculated and measured permeabilities are in good agreement.

• Korean Journal of Pharmacognosy
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• v.39 no.4
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• pp.310-315
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• 2008

Viscum album coloratum (Korean mistletoe; KM) is a semi-parasitic plant growing on various trees. This plant hasbeen shown to possess a variety of biological functions such as immunomodulation, apoptosis-induction and antitumor activity. However, there is no information about how the extract of KM affects life span of the host. In this study, in order to examine the effect of KM on the longevity of the host, we investigated whether a Korean mistletoe extract (KME) was able to extend the life length in an experimental model using the spring silkworm moth of Bombyx mori (Lepidoptera bombycidae). We established a model test for survival in which all of the male and female moths died within 18 days after the beginning of the experiment. Mean survival time of female moths was longer than that of male moths. Both male and female moths fed with KME containing diet (200 or 400 ${\mu}g$/head/day) showed significantly higher mean survival times than those of the control moths. Studying the effect of KME on prolongation of mean survival time showed that male moths were more susceptible than female moths. The moths fed with KME-containing diet showed a slight decrease in body weight. Interestingly, however, no difference in food intake was observed between moths fed with KME-containing diet and those with control diet. In analysis for mRNA increase in the SIRT2 gene, a member of the Sir2 gene family playing important roles in regulation of cell death and prolongation of life span, moths fed with KME-containing diet showed a significant increase in SIRT2 gene expression. These results suggest that KME has a potential to extend the life span in Bombyx mori, and its effect is partly associated with increase in SIRT2 gene expression.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.459-465
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• 2011

It has been reported that the femoral morphology has a major correlation to femoral neck fractures(FNF). Previous studies to analyze these correlations have relied on mechanical testing and finite element methods. However, these methods have not been widely applied to various femur samples and models. It is because of the availability of the samples from both patients and cadavers, and also of the geometric limitations in changing the shape of the models. In this study we analyzed femoral neck fractures using a parameterized femoral model that could provide flexibility in changing the geometry of the model for the wide applications of FNF analysis. With the parameterization a variety of models could be generated by changing four major dimensions: femoral head diameter(FHD), femoral neck diameter(FND), femoral neck length(FNL), and neck-shaft angle(NSA). We have performed FEA on the models to compute the stress distributions and reaction forces, and compare them with the data previously generated from mechanical testing. The analysis results indicate that the FND is significantly related with the FNF and the FHD is not significantly related with the FNF.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.3
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• pp.143-149
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• 2012

Groundwater flow simulations were performed to obtain data of groundwater flow used in a safety assessment for a hypothetical geological disposal facility assumed to be located in the KURT (KAERI Underground Research Tunnel) site. A regional scale modeling of the groundwater flow system was carried out to make boundary conditions for a local scale modeling. And, fracture zones identified at the study site were involved in the local scale groundwater flow model. From the results of the local scale modeling, a hydraulic head distribution was indicated and it was used in a particle tracking simulation for searching pathway of groundwater from the location of the hypothetical disposal facility to the surface where the groundwater reached. The flow distance and discharge rate of the groundwater in the KURT site were calculated. It was thought that the modeling methods used in this study was available to prepare the data of groundwater flow in a safety assessment for a geological disposal facility of radioactive wastes.

• Journal of Ginseng Research
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• v.42 no.2
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• pp.183-191
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• 2018

Background: Ginseng saponin has long been used as a traditional Asian medicine and is known to be effective in treating various kinds of pain. Ginsenoside Rf is one of the biologically active saponins found in ginseng. We evaluated ginsenoside Rf's antinociceptive and anti-inflammatory effects, and its mechanism of action on adrenergic and serotonergic receptors, in an incisional pain model. Methods: Mechanical hyperalgesia was induced via plantar incision in rats followed by intraperitoneal administration of increasing doses of ginsenoside Rf (vehicle, 0.5 mg/kg, 1 mg/kg, 1.5 mg/kg, and 2 mg/kg). The antinociceptive effect was also compared in a Positive Control Group that received a ketorolac (30 mg/kg) injection, and the $Na{\ddot{i}}ve$ Group, which did not undergo incision. To evaluate the mechanism of action, rats were treated with prazosin (1 mg/kg), yohimbine (2 mg/kg), or ketanserin (1 mg/kg) prior to receiving ginsenoside Rf (1.5 mg/kg). The mechanical withdrawal threshold was measured using von Frey filaments at various time points before and after ginsenoside Rf administration. To evaluate the anti-inflammatory effect, serum interleukin $(IL)-1{\beta}$, IL-6, and tumor necrotizing $factor-{\alpha}$ levels were measured. Results: Ginsenoside Rf increased the mechanical withdrawal threshold significantly, with a curvilinear dose-response curve peaking at 1.5 mg/kg. $IL-1{\beta}$, IL-6, and tumor necrotizing $factor-{\alpha}$ levels significantly decreased after ginsenoside Rf treatment. Ginsenoside Rf's antinociceptive effect was reduced by yohimbine, but potentiated by prazosin and ketanserin. Conclusion: Intraperitoneal ginsenoside Rf has an antinociceptive effect peaking at a dose of 1.5 mg/kg. Anti-inflammatory effects were also detected.

• Progress in Medical Physics
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• v.22 no.2
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• pp.79-84
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• 2011

In this study, Geant4 based Monte Carlo simulations were carried out for medical linear accelerator. Modified Medical Linac2 toolkit was used for calculation. The energy spectrum, most probable energy and the photon mean energy compared with the published results using the EGS4 code. The results well agreed with published results. The calculated results of photon fluence, energy fluence and mean energy according to the radius from the centre of the beam were analyzed. Monte Carlo simulation using Medical Linac2 code is considered to be useful for analysis of medical linear accelerator. Because the calculated results varies depending on Physics List model for same head structure. It it important to choose the right model for research purpose. Monte Carlo simulation using GEANT4 Medical Linac2 is a valuable for any novice to adopt this code to the study related to 6 MV photon fluence from medical linear accelerator.

• Journal of the Korean Geotechnical Society
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• v.29 no.6
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• pp.5-17
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• 2013

Slug tests can be adopted to estimate hydraulic conductivity of the slurry trench wall backfill for its abilities to reflect the in-situ performance of the construction. A comprehensive three-dimensional numerical model is developed to simulate the slug test in a slurry trench wall considering the presence of bentonite cake on the interface boundaries between the wall and the surrounding soil formation. Influential factors such as wall width (i.e., proximity of wall boundary), well deviation, vertical position of well intake section, compressibility of wall backfill, etc. are taken into account in the model. A series of simulation results are examined to evaluate the bentonite cake effect in analyzing practical slug test results in the slurry trench wall. The results show that the modified line-fitting method can be used without any correction factor for the slug test in the slurry trench wall with the presence of bentonite cake. A case study is reanalyzed with the assumption of existing bentonite cake. The results are compared with the previously reported results by the approaches assuming no bentonite cake (constant-head boundary) or upper-bound solution (no-flux boundary). The case study demonstrates the bentonite cake effect and the validity of the modified line-fitting method in the estimation of the hydraulic conductivity of the slurry wall backfill.

• Tunnel and Underground Space
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• v.30 no.5
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• pp.496-507
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• 2020

A prediction of the performance of EPB TBM is significant for improving the constructability of tunnels. Thus, various attempts to simulate TBM excavation by the numerical method have been made until these days. In this paper, to evaluate the performance of TBM with different operating conditions, a parametric study was carried out using coupled discrete element method (DEM) and finite difference method (FDM) EPB TBM driving model. The analysis was conducted by changing the penetration rate (0.5 and 1.0 mm/sec) and the rotational speed of screw conveyor (5, 15, and 25 rpm) while the rotation velocity of the cutter head kept constant at 2 rpm. The torque, thrust force, chamber pressure, and discharging with different TBM operating conditions were compared. The result of parametric study shows that the optimum driving condition can be determined by the coupled DEM-FDM numerical model.

• Journal of the Korean Geotechnical Society
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• v.33 no.8
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• pp.5-16
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• 2017

When a lateral load is applied to a short pile whose embedded depth is relatively smaller than its diameter, an overturning failure occurs. To investigate the behavior of laterally loaded short piles, several model tests in laboratory scales had been carried out, however the behavior of large moment carrying piles for electric poles, traffic sign and road lamp, etc. have not been revealed yet. This paper deals with the real-scale load tests for 750 mm diameter short piles. To simulate the actual loading condition, very large moment was mobilized by applying lateral loads to the location 8 m away from the pile head. Three load tests changing the pile embedded lengths to 2.0 m, 2.5 m, and 3.0 m were carried out. The test piles overturned abruptly with very small displacement and rotation before the failures. These brittle failures are in contrast with the ductile failures shown in the former model tests with the relatively smaller moment to lateral load ratio. Comparisons of the test results with three existing methods for the estimation of the ultimate lateral capacity show that the method assuming the rotation point at pile tip matches well when the embedded depth is small, however, as the embedded depth increases the other two methods assuming the inversion of soil pressure with respect to rotation points in pile length match better.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5965-5972
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• 2013

PIN1 is one member of the parvulin PPIase family. By controlling Pro-directed phosphorylation, PIN1 plays an important role in cell transformation and oncogenesis. There are many polymorphisms in the PIN1 gene, including rs2233678 and rs2233679 affecting the PIN1 promoter. Recently, a number of case-control studies were conducted to investigate the association between PIN1 gene rs2233678 and rs2233679 polymorphism and cancer risk. However, published data are still conflicting. In this paper, we summarized data for 5,427 cancer cases and 5,469 controls from 9 studies and attempted to assess the susceptibility of PIN1 gene polymorphism to cancers by a synthetic meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the relationship. All analyses were performed using Stata software. Our results suggested that rs2233678 represented a protective factor in overall analysis (CC vs GG: OR= 0.697, 95%CI: 0.498-0.976; CG vs GG: OR=0.701, 95%CI: 0.572-0.858; Dominant model: OR= 0.707, 95%CI: 0.590-0.847; C allele vs G allele: OR=0.734, 95%CI: 0.623-0.867) and especially for squamous cell carcinoma of the head and neck, lung cancer and breast cancer in Asians and Caucasians. The rs2233679 polymorphism was significantly associated with decreased cancer risk in overall analysis (CT vs CC: OR=0.893, 95%CI=0.812-0.981; Dominant model: OR=0.893, 95%CI=0.816-0.976; T allele vs C allele; OR=0.947, 95%CI=0.896-1.000) and especially in Asians. In conclusion, our meta-analysis suggested that -842G>C (rs2233678) and -667C>T (rs2233679) may contribute to genetic susceptibility for cancer risks. Further prospective research with larger numbers of worldwide participants is warranted to draw comprehensive and firm conclusions.