• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.789-799
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• 2019

The settlement hardly occurs in structures supported by pile foundation such as abutment, culvert but a cavity is formed in the lower part of a structure. As a result, soil discharged from the lateral ground to the cavity accelerates the settlement of the lateral ground of the structure, resulting in a larger settlement. Therefore, in order to prevent problems caused by cavity under the structure supported by pile foundation, soil Flow Protector (briefly called 'FLP'), which can be easily installed on the side of structure, was developed. In this study, an laboratory model test was carried out to prove the reduction effect of settlement and to estimate the optimal installation length of the FLP. As a result, the installation of the FLP reduced the settlement of the lateral ground and prevented the leakage of lateral ground soil into the cavity. If the stiffness of the FLP is small, the state or active earth pressure is generated in the upper part, which is not favorable for stability. But if the stiffness of the FLP is high enough, the passive earth pressure area is generated in the upper part, which will be advantageous for the stability. Also, the increased installation length of FLP is effective to reduce the settlement. And the ratio of the optimal length of the FLP to the box structure height (H = 250 mm) are flexible FLP 1.38, stiff FLP 0.73.

• The Journal of Internal Korean Medicine
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• v.30 no.2
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• pp.270-287
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• 2009

Objective : Yinjinchunggan-tang(YJCGT) is reported previously as having theraputic effects on hepatitis such as anti-implammatory, anti-apoptotic, anti-viral(HBV), etc. Though this prescription is not studied on its anti-fibrogenic effect, it is still expected to have the effect in the liver. Thus, this study was performed to investigate the anti-fibrogenic effect of YJCGT on thioacetamide(TAA)-induced liver fibrosis in rats. Method: Rat liver fibrosis was induced by intraperitoneal TAA injection(150mg/kg) 3 times a week for 5 weeks. After the YJCGT (YJCGT 1g/kg, YJCGT 2g/kg)-treatment, body weight, liver and spleen weights, liver function test, the complete blood count and the portal pressure were studied. In addition, gene expressions of ASMA, procollagen type Ia2, MMP2, TIMP1 and TIMP2, all of which are known to be associated with liver fibrosis, were analyzed by RT-PCR. After YJCGT (YJCGT 1g/kg, YJCGT 2g/kg) treatment, percentages of collagen in TAA-induced rat liver tissue were measured by image analyzer. Results : The body weight of the normal group increased more than that of the control and YJCGT-treated groups. The AST level of the YJCGT lg/kg-treated group significantly decreased compared to that of the control. The ALT and the GGT levels of the YJCGT 2g/kg-treated group significantly increased compared to those of the control. In the YJCGT-treated groups. WBC, RBC and Hgb elevated by TAA injection decreased but platelet count increased. In the YJCGT lg/kg-treated group, the portal pressure elevated by TAA injection significantly decreased. The significant decreases in the gene expressions of procollagen type Ia2, MMP2 and TIMP2 were observed in the YJCGT-treated groups. In histological findings. TAA injections caused severe liver fibrosis, but the YJCGT treatment significantly reduced the amounts of hepatic collagens. Conclusions: These results suggest that YJCGT has beneficial effects on the treatment of patients with liver cirrhosis as well as chronic hepatitis. Further study should be done to decide the optimal concentration of the YJCGT for the treatment of liver cirrhosis.

• The Journal of Internal Korean Medicine
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• v.32 no.2
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• pp.153-169
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• 2011

Objectives : This study was performed to investigate the anti-fibrogenic effect and the effect on cell growth and apoptosis in YJCGT, YJCGT YSO and YJCGT YSCO on thioacetamide-induced rat liver tissue and the immortalized human hepatic cell line LX2. Materials and Methods : LX2 cells were treated with various concentrations (0, 50, 150, 300 ug/ml) of YJCGT, Y+YSO, and Y+YSCO extract for 24, 48 and 72 hours. After the treatment, cell viability was measured by using MTT assay. Caspase inhibitor assay, and cell viability were determined by a colorimetric assay with PMS/MTS solution. Rat liver fibrosis was induced by intraperitoneal thioacetamide injection 150 mg/kg 3 times a week for 5 weeks. After the treatment, body weight, liver & spleen weights, liver function test, the complete blood cell count and the change of portal pressure were studied. After YJCGT, Y+YSO, and Y+YSCO treatment, percentages of collagen in thioacetamide-induced rat liver tissue were measured. Results : The viability of the LX2 cell decreased in a dose- and time-dependent manner. Exposure of LX2 cells to YJCGT, YJCGT+YSO and YJCGT+YSCO induced caspase-3 activation, but co-treatment of YJCGT, YJCGT+YSO and YJCGT+YSCO with the pan-caspase inhibitor Z-VAD-FMK, and the caspase-3 inhibitor Z-DEVE-FMK, blocked apoptosis. There was no difference in rat body weight between the thioacetamide only group and the YJCGT, YJCGT+YSO and YJCGT+YSCO groups. In the YJCGT, YJCGT YSO and YJCGT YSCO groups, the serum level of GPT significantly went down compared with the thioacetamide only group. In the YJCGT, Y+YSO, Y+YSCO groups, white blood cell elevated by thioacetamide injection decreased but RBC, Hgb, and Hct increased. In the Y+YSO group, the portal pressure elevated by thioacetamide injection significantly decreased. In the histological finding, thioacetamide injections caused severe fibrosis, but YJCGT, Y+YSO, and Y+YSCO treatment significantly reduced the amounts of hepatic collagens. Conclusions : YJCGT, Y+YSO, and Y+YSCO inhibit the growth of LX2 cells by inducing apoptosis through caspase activity. YJCGT, Y+YSO, and Y+YSCO have beneficial effects on the treatment of cirrhotic patients as well as patients with chronic hepatitis.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.193-206
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• 2018

In this study, as part of the "Small-scale $CO_2$ Injection-Demonstration Project in Offshore Pohang Basin", we performed drilling and completion of a $CO_2$ injection well from the offshore platform installed in the Yeongil Bay, Pohang city, Gyeongsang buk-do. The drilling of injection well was carried out from an offshore platform installing on the sediment formations of the Pohang Basin. Drilling diameters were reduced by stages, depending on the formation pressure and groundwater pressure along a depth and the casing installation and cement grouting in drilled hole were performed at each stage. The injection well was drilled to a final depth of 816.5 m with a hole diameter of 4 7/8 inches (${\Phi}124mm$) and the perforated casing for an injection section was installed in a depth of 746.5~816.5 m. Injection tubing, packer, and christmas tree were installed for the completion of an injection well for $CO_2$. The validation project of the $CO_2$ injection was accomplished successfully by drilling the injection well and installing the injection facilities, and through the suitable $CO_2$ injection process. The current injection facility is a facility for small-scale injection demonstration of 100 tons. In the case of large-scale demonstration facility test of a capacity of 10,000 tons, research is underway through the upgrading of the injection facilities.

• The Journal of Internal Korean Medicine
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• v.31 no.2
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• pp.314-330
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• 2010

Objective : This study was performed to investigate the anti-fibrogenic effect and changes of inflammation-related genes by YBR I and YBR II (YBR I: Arteisiae Capillaris Herba, Atractylodis Rhizoma Alba, Hoelen/ YBR II: YBR I +Sanguisorbae Radix, Biotae Cacumen, Cirsii Japonici Herba) on HSC(hepatic stellate cells)-T6 and TAA-induced rat liver tissue. Materials and Methods : HSC-T6 were treated with various concentrations of distilled-water extract YBR I and YBR II extract for 24, 48 and 72 hours. After the treatment, cell viability, proliferation, procollagen levels and IL-6 levels were measured by using MTT Assay, BrdU Assay, Procollagen Type 1 C-peptide EIA kit, and Murine IL-6 ELISA Development kit. Rat liver fibrosis was induced by intraperitoneal TAA injection of 150mg/kg 3 times a week for 6 weeks. After the treatment, body weight, liver & spleen weights, liver function test, complete blood cell count and change of portal pressure were studied. In addition, gene expressions of ASMA, IL-6, MMP-2, TIMP-1 and TIMP-2, all of which are known to be associated with liver fibrosis, were analyzed by using Real-Time PCR. After YBR I and YBR IItreatment, percentages of collagen in TAA-induced rat liver tissue were measured. Results : The viability and proliferation of the HSC-T6 decreased as the concentration increased. The production of procollagen decreased as the concentration increased. The production of IL-6 was little influenced by YBR I and YBR II. There was no difference in rat body weight between the TAA-only group and the YBR groups. Compared with rat liver weight of TAA-only group, that of the YBR groups increased. In the YBR I group, the serum level of AST elevated by TAA injection significantly decreased and in the YBR I and II group, the serum level of ALP and ALT elevated by TAA injection decreased. In the YBR I group, white blood cell count elevated by TAA injection decreased but platelets increased. In the YBR I group, the portal pressure elevated by TAA injection significantly decreased. Decreases in the gene expression of ASMA and MMP-2 were observed in the YBR I group. The gene expression of IL-6 was little influenced by YBR I and YBR II -treated groups. In the histological finding, TAA injections caused severe fibrosis, but YBR I and YBR II treatment significantly reduced the amounts of hepatic collagens. Conclusions : These results suggest that YBR I and II have inhibitory effects on the hepatic fibrogenesis.

• Journal of Drive and Control
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• v.13 no.2
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• pp.10-18
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• 2016

A front-end loader (FEL) mounted on an agricultural tractor is one of the most commonly used implements to mechanize routine agricultural tasks. When the FEL is used with a loaded bucket, careful operation is required to maintain safety and avoid spillage when the tractor passes a bump because a change in the gravity center of the tractor due to varied loadings can affect the stability of the tractor. Use of a boom suspension system consisting of accumulators and orifice dampers can be instrumental in reducing pitching vibrations while increasing the handling performance of the FEL-mounted tractor. The objective of this research was to reduce bump shocks by adding an orifice and a flow control valve to the original hydraulic circuit composed solely of accumulators. A simulation study was performed using the SimulationX program to investigate the effects of an accumulator and an orifice-throttle damper on bump shocks. Results showed that the peak pressure on a boom cylinder and the vertical acceleration of a bucket were significantly affected by use of both an accumulator and an orifice damper. In a field test conducted with a 75-kW tractor, the peak pressure of the boom cylinder, and the root mean square (RMS) vertical acceleration of the bucket and seat were reduced by on average, 23.0, 42.2, and 44.9% respectively, as compared to those measured with the original accumulator system, showing that an improved design for the accumulator hydraulic circuit can reduce bump shocks. Further studies are needed to design a tractor suspension system that includes the effects of cabin suspension and tires as well as dynamic analysis.

• Composites Research
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• v.26 no.6
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• pp.363-372
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• 2013

Numerical simulation for Resin Transfer Molding manufacturing process is attempted by using the eXtended Finite Element Method (XFEM) combined with the level set method. XFEM allows to obtaining a good numerical precision of the pressure near the resin flow front, where its gradient is discontinuous. The enriched shape functions of XFEM are derived by using the level set values so as to correctly describe the interpolation with the resin flow front. In addition, the level set method is used to transport the resin flow front at each time step during the mold filling. The level set values are calculated by an implicit characteristic Galerkin FEM. The multi-frontal solver of IPSAP is adopted to solve the system. This work is validated by comparing the obtained results with analytic solutions. Moreover, a localization method of XFEM and level set method is proposed to increase the computing efficiency. The computation domain is reduced to the small region near the resin flow front. Therefore, the total computing time is strongly reduced by it. The efficiency test is made with a simple channel flow model. Several application examples are analyzed to demonstrate ability of this method.

• Membrane Journal
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• v.24 no.3
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• pp.213-222
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• 2014

In this study, 2-stage recirculation membrane process was developed for purification of high purity bio-methane for the vehicle fuel application. Pure gas permeation and mixture gas permeation test were done as a function of methane content and pressure in the feed using polysulfone membrane modules. 2-stage membrane plant was designed, constructed in a food waste treatment cite. Dehumidification, dry desulfurization, and desiloxane plants are installed for the removal of $H_2O$, $H_2S$ and siloxane in the biogas. Permeation test were done with the pre-treated methane mixture in terms of methane purity and recovery by adjusting the ratio of membrane area (1:1, 1:3, 2:2) in the first and second membrane modules in the plant. When membrane area of 2 stage increased to $3m^2$ from $1m^2$ at 1-stage membrane area of $1m^2$, the feed rate and $CH_4$ recovery at 95% methane purity were increased from 47.1% to 92.5% respectively. When the membrane area increased two-fold (1:1 to 2:2), $CH_4$ recovery increased from 47.1% to 88.3%. When the feed flow rate was increased, in 1:3 ratio, final purity of the methane is reduced, the methane recovery is increased. When operating pressure was increased, the feed rate was increased and recovery was slightly decreased. From this result, membrane area, feed pressure and feed rate could be the important factor to the performance of the membrane process.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.773-780
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• 1999

Background: It has been demonstrated that brief periods of calcium depletion and repletion (calcium-free preconditioning, CP) have cardioprotective effects as seen in ischemic preconditioning(IP) which enhances the recovery of post-ischemic contractile dysfunction and reduces the incidence of reperfusion-induced arrhythmia or infarct size after a prolonged ischemia. In the present study, we tested this paradoxical phenomenon in isolated rabbit hearts. Material and Method: Hearts isolated from New Zealand white rabbits(1.5∼2.0 Kg body weight) were perfused with Tyrode solution using the Langendorff technique. After stabilizing the baseline hemodynamics, the hearts were subjected to 45 minutes of global ischemia followed by 120 minutes of reperfusion with IP(IP group, n=7) or without IP (ischemic control group, n=7). IP was induced by a single episode of 5 minutes global ischemia and 10 minutes reperfusion. In the CP group(n=7), the hearts were subjected to perfusion with Tyrode solution with calcium depletion for 5 minutes and repletion for 10 minutes, and 45 minutes of ischemia and 120 minutes of reperfusion. Left ventricular function including developed pressure, dP/dt, heart rate, left ventricular end-diastolic pressure and coronary flow was measured. Infarct size was determined by staining with 1% triphenyltetrazolium chloride and planimetry. Data were analyzed by a one-way analysis of variance and Tukey's post-hoc test. Result: In comparison with the ischemic control group, IP significantly enhanced the recovery of the left ventricular function including the left ventricular developed pressure, contractility, and coronary flow; in contrast, these functional parameters of the CP group tended to be lower than those of the ischemic control group. However, the infarct size was significantly reduced by IP or CP(p<0.05). Conclusion: These results suggest that in isolated Langendorff-perfused rabbit heart model, CP(induced by single episode of 5 minutes calcium depletion and 10 minutes repletion) could not improve the post-ischemic contractile dysfunction(after a 45-minute global ischemia) but it has an infarct size-limiting effect.

• Journal of Chest Surgery
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• v.32 no.7
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• pp.603-612
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• 1999

Background : It has been documented that brief repetitive periods of ischemia and reperfusion (ischemic preconditioning, IP) enhances the recovery of post-ischemic contractile function and reduces infarct size after a longer period of ischemia. Many mechanisms have been proposed to explain this process. Recent studies have suggested that transient increase in the intracellular calcium may have triggered the activation of protein kinase C(PKC); however, there are still many controversies. Accordingly, the author performed the present study to test the hypothesis that preconditioning with high concentration of calcium before sustained subsequent ischemia(calcium preconditioning) mimics IP by PKC activation. Material and Method : The isolated hearts from the New Zealand White rabbits(1.5∼2.0 kg body weight) Method: The isolated hearts from the New Zealand White rabbits(1.5∼2.0 kg body weight) were perfused with Tyrode solution by Langendorff technique. After stabilization of baseline hemodynamics, the hearts were subjected to 45-minute global ischemia followed by a 120-minute reperfusion with IP(IP group, n=13) or without IP(ischemic control, n=10). IP was induced by single episode of 5-minute global ischemia and 10-minute reperfusion. In the Ca2+ preconditioned group, perfusate containing 10(n=10) or 20 mM(n=11) CaCl2 was perfused for 10 minutes after 5-minute ischemia followed by a 45-minute global ischemia and a 120-minute reperfusion. Baseline PKC was measured after 50-minute perfusion without any treatment(n=5). Left ventricular function including developed pressure(LVDP), dP/dt, heart rate, left ventricular end-diastolic pressure(LVEDP) and coronary flow(CF) was measured. Myo car ial cytosolic and membrane PKC activities were measured by 32P-${\gamma}$-ATP incorporation into PKC-specific pepetide. The infarct size was determined using the TTC (tetrazolium salt) staining and planimetry. Data were analyzed using one-way analysis of variance(ANOVA) variance(ANOVA) and Tukey's post-hoc test. Result: IP increased the functional recovery including LVDP, dP/dt and CF(p<0.05) and lowered the ascending range of LVEDP(p<0.05); it also reduced the infarct size from 38% to 20%(p<0.05). In both of the Ca2+ preconditioned group, functional recovery was not significantly different in comparison with the ischemic control, however, the infarct size was reduced to 19∼23%(p<0.05). In comparison with the baseline(7.31 0.31 nmol/g tissue), the activities of the cytosolic PKC tended to decrease in both the IP and Ca2+ preconditioned groups, particularly in the 10 mM Ca2+ preconditioned group(4.19 0.39 nmol/g tissue, p<0.01); the activity of membrane PKC was significantly increased in both IP and 10 mM Ca2+ preconditioned group (p<0.05; 1.84 0.21, 4.00 0.14, and 4.02 0.70 nmol/g tissue in the baseline, IP, and 10 mM Ca2+ preconditioned group, respectively). However, the activity of both PKC fractions were not significantly different between the baseline and the ischemic control. Conclusion: These results indicate that in isolated Langendorff-perfused rabbit heart model, calcium preconditioning with high concentration of calcium does not improve post-ischemic functional recovery. However, it does have an effect of limiting(reducing) the infart size by ischemic preconditioning, and this cardioprotective effect, at least in part, may have resulted from the activation of PKC by calcium which acts as a messenger(or trigger) to activate membrane PKC.