• Korean Journal of Materials Research
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• v.33 no.1
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• pp.21-28
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• 2023

The electromembrane process, which has advantages such as scalability, sustainability, and eco-friendliness, is used in renewable energy fields such as fuel cells and reverse electrodialysis power generation. Most of the research to visualize the internal flow in the electromembrane process has mainly been conducted on heterogeneous ion exchange membranes, because of the non-uniform swelling characteristics of the homogeneous membrane. In this study, we successfully visualize the electro-convective vortices near the Nafion homogeneous membrane in PDMS-based microfluidic devices. To reinforce the mechanical rigidity and minimize the non-uniform swelling characteristics of the homogeneous membrane, a newly developed swelling supporter was additionally adapted to the Nafion membrane. Thus, a clear image of electroconvective vortices near the Nafion membrane could be obtained and visualized. As a result, we observed that the heterogeneous membrane has relatively stronger electroconvective vortices compared to the Nafion homogeneous membranes. Regarding electrical response, the Nafion membrane has a higher limiting current and less overlimiting current compared to the heterogeneous membrane. Based on our visualization, it is assumed that the heterogeneous membrane has more activated electroconvective vortices, which lower electrical resistance in the overlimiting current regime. We anticipate that this work can contribute to the fundamental understanding of the ion transport characteristics depending on the homogeneity of ion exchange membranes.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.81-88
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• 2010

This study was conducted to find the capability of comparison of overall oxygen transfer coefficient in the membrane coupled high performance reactor (MPHCR) in treating high organic loading wastewater. Effluent quality had been analyzed while the influent organic loading rate was changed from 2 to $7kg\;COD/m^3{\cdot}day$. The oxygen transfer coefficients had been investigated using two-phase nozzle for operating variables which were internal circulation flowrate (5~8 L/min), air flow rate (0.0125~0.2 L/min), liquid temperature ($10{\sim}20^{\circ}C$), and pure-oxygen flow rate (0.0125~0.2 L/min). The overall oxygen transfer coefficient was increased with flowrate of internal circulation and air and high temperature. Especially, internal circulation flow rate showed distinct effect on overall oxygen transfer coefficient due to an increase of gas holdup and air-liquid contract area by two-phase nozzle. In the high range of organic loading rate from 4 to $7kg\;COD/m^3{\cdot}day$, the removable efficiency of COD was 91%. Conventional activated sludge process usually treat organic loading from 0.32 to $0.64kg\;COD/m^3{\cdot}day$ however, the MPHCR can treat 10 to 20 times higher if it would be compared to the conventional activated sludge process. Foaming problem often happened and caused biomass wash out of the reactor, therefore, the foaming should be controlled for the enhanced operation.

• Journal of Gastric Cancer
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• v.18 no.1
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• pp.37-47
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• 2018

Purpose: The endoscopic management of a fully covered self-expandable metal stent (SEMS) has been suggested for the primary treatment of patients with anastomotic leaks after total gastrectomy. Embedded stents due to tissue ingrowth and migration are the main obstacles in endoscopic stent management. Materials and Methods: The effectiveness and safety of endoscopic management were evaluated for anastomotic leaks when using a benign fully covered SEMS with an anchoring thread and thick silicone covering the membrane to prevent stent embedding and migration. We retrospectively reviewed the data of 14 consecutive patients with gastric cancer and anastomotic leaks after total gastrectomy treated from January 2009 to December 2016. Results: The technical success rate of endoscopic stent replacement was 100%, and the rate of complete leaks closure was 85.7% (n=12). The mean size of leaks was 13.1 mm (range, 3-30 mm). The time interval from operation to stent replacement was 10.7 days (range, 3-35 days) and the interval from stent replacement to extraction was 32.3 days (range, 18-49 days). The complication rate was 14.1%, and included a single jejunal ulcer and delayed stricture at the site of leakage. No embedded stent or migration occurred. Two patients died due to progression of pneumonia and septic shock 2 weeks after stent replacement. Conclusions: A benign fully covered SEMS with an anchoring thread and thick membrane is an effective and safe stent in patients with anastomotic leaks after total gastrectomy. The novelty of this stent is that it provides complete prevention of stent migration and embedding, compared with conventional fully covered SEMS.

• THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
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• v.9 no.1
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• pp.15-37
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• 2003

Objective: We are aimed to identify anti-tumor effects of Curcuma longa L. on the stomach cancer cells through molecular biologic methods. Material & Methods: We used AGS as human stomach cancer cells obtained from American Type Culture Collection. The boiled extract of Curcuma longa L. $5{\mu}l$ (Sample I), $10{\mu}l$ (Sample II) was treated to cultural media(ml) for 0, 6, 12, 24, 48 hours. We measured the killing effect on stomach cancer cells through Trypan blue exclusion test and the suppressive effect on viability of stomach cancer cells via MTT assay. For identification of its anticancer mechanism, the revelation of Bcl-2, Bcl-XL, and Bax which are genes related to apoptosis using the quantitative RT-PCR, change of mitochondria membrane permeability and membrane potential via flow cytometry, the cycle of cell mitosis, caspase cleavage and annexin V staining were examined. Results: 1. showed significant killing effect on stomach cancer cell than the control group with a time(6 hours later) and density dependent manner, which was statistical significance. 2. Extract of Curcuma longa L. showed suppressive effect on viability of stomach cancer cells that each test groups had more suppressive effects on viability of stomach cancer cells than the control group with a time(6 hours later), which was statistical significance.(p<0.05) 3. In the test about the revelation of genes related to apoptosis, the revelation of Bcl-2 and Bcl-XL decreased with a density manner which was statistical significance. but the revelation of Bax was not changed with statistical significance. 4. Extract of Curcuma longa L. caused apoptosis by decreasing the absorbance of mitochondria with statistical significance, and also induced apoptosis by decreasing the membrane potential of mitochondria. 5. Extract of Curcuma longa L. destructed the cell cycle of cell mitosos. 6. Cell apoptosis was induced by extract of Curcuma longa L. certificated by method of caspase cleavage and annexin V staining. Conclusion: This experiment showed that Curcuma longa L. has anti-tumor effect with statistical significance. This is in vitro experiment and basic experiment on Curcuma longa L.. We hope more progressive research on Curcuma longa L. will go on and its anti-tumor effects will be more practically identified.

• Tuberculosis and Respiratory Diseases
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• v.66 no.5
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• pp.380-384
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• 2009

Drug-induced subacute cutaneous lupus erythematosus (SCLE) is associated with use of the following classes of medications: anti-hypertensives, anti-cholesterolemia, anti-psychotics, and anti-inflammatory drugs. Docetaxel is an anti-neoplastic agent, which is widely used for treatment of non-small cell lung cancer. Few cases of docetaxel-induced SCLE have been reported in the medical literature. Here, we report the case of a 58-year-old female patient who developed drug-induced SCLE after administration of docetaxel. After 4 cycles of chemotherapy with docetaxel and cisplatin, erythematous skin eruptions developed on the patient's face. Skin biopsies of the eruptions were remarkable for interfacing dermatitis with basement membrane thickening. Immunofluorescent study revealed characteristic features of SCLE, including granular deposition of IgM, C3, and apoptotic bodies along the basement membrane. The skin eruptions resolved gradually after cessation of drug and with the use of topical corticosteroids.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.285-289
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• 2017

Pheochromocytoma can present with various symptoms including cardiogenic shock and cardiac arrest. Particularly, in cases of cardiogenic shock of unknown origin, pheochromocytoma should be considered. A 20-year-old woman without any medical history visited our emergency department due to nausea, vomiting, headache, and chest pain. Echocardiography revealed severe left ventricular dysfunction. Mechanical ventilation and veno-arterial extracorporeal membrane oxygenation (ECMO) were implemented owing to her unstable vital signs. For unstable vital sign and cardiogenic shock in a young woman without any previous medical history, pheochromocytoma was considered and diagnosed based on elevated levels of catecholamine derivatives in a 24-hour urine sample. Cardiac function recovered and ECMO was discontinued on the 5th day of hospitalization. She later underwent an elective adrenalectomy and no recurrence was found during the follow-up period. We reported a case of pheochromocytoma which was presented with cardiogenic shock in a young woman with no concomitant disease, and successfully treated with ECMO followed by an elective adrenalectomy.

• Journal of Korean Neurosurgical Society
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• v.64 no.1
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• pp.110-119
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• 2021

Objective : Preoperative prediction of the arachnoid membrane descent in pituitary surgery is useful for achieving gross total removal and avoiding cerebrospinal fluid leakage resulting from tearing of the arachnoid membrane in the chiasmatic cistern. In this study, we analyzed the patterns of arachnoid membrane descent during or after pituitary tumor surgery and identified the factors related to this descent. Methods : Analysis was restricted to pituitary macroadenomas not extending into the third ventricle or over the internal carotid artery. To minimize confounding factors, patients who underwent revision surgery, those who had a torn arachnoid during operation or small medial diaphragma sellae (DS) opening, and subtotal resections were excluded. We enrolled 41 consecutive patients in this retrospective analysis. The degree of arachnoid descent was categorized using intraoperative videos. Preoperative magnetic resonance findings, including tumor height, suprasellar extension, and variables including DS area and medial opening size, tumor composition, and displacement of the pituitary stalk and gland were evaluated to determine their correlations with arachnoid membrane descent. Results : Arachnoid membrane descent was significantly correlated with DS area and medial opening size. Based on T2-weighted images (T2WI) magnetic resonance (MR) images, tumor composition was significantly associated with arachnoid membrane descent. Other factors were not significantly correlated with arachnoid membrane descent. Conclusion : T2WI of tumor composition and preoperative MR imaging of DS area and medial opening provided valuable information regarding arachnoid membrane descent. These parameters may serve as fundamental measures to facilitate complete resection of pituitary macroadenomas.

• The Korean Journal of Physiology
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• v.25 no.1
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• pp.17-26
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• 1991

Single smooth muscle cells of the rabbit pulmonary artery were isolated by treatment with collagenase and elastase. Using the patch clamp technique, potassium channel activity was recorded from the inside-out membrane patch. The channel had a sin히e channel conductance of about 360 pS in symmetrical concentration of K on both sides of the patch, 150 mM, and had a linear current-voltage relationship. During the application of 10 mM tetraethylammonium (TEA) to the intracellular membrane surface, the amplitude of single channel current was reduced and very rapid flickering appeared. The open probability $(P_0)$ of this channel was increased by increasing positivity of the potential across the patch membrane, with e-fold increase by 20 mV depolarization, and by increasing the internal $Ca^{2+}$ concentration. These findings are consistent with those of large conductance Ca-activated K channels reported in other tissues. But the shortening of the mean open time by increasing $[Ca^{2+}]_i$, was an unexpected result and one additional closed state which might be arisen from a block of the open channel by Ca binding was suggested. The $P_0-membrane$ potential relationship was modulated by internal pH. Decreasing pH reduced $P_0$. Increasing pH not only increased $P_0$ but also weakened the voltage dependency of the channel opening. The modulation of Ca-activated K channel by pH was thought to be related to the mechanism of regulation of vascular tone by the pH change.

• Journal of Korean Society on Water Environment
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• v.25 no.1
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• pp.120-124
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• 2009

This study was performed to investigate the application of submerged membrane bioreactor (MBR) system for biological nutrient removal of municipal wastewater. MBR bioreactor consists of four reactors such as anaerobic, stabilization, anoxic and submerged membrane aerobic reactors with two internal recycles. The hydraulic retention time (HRT), sludge retention time (SRT) and flux were 6.2 hr, 34.1 days and $19.6L/m^2/hr$ (LMH), respectively. As a result of operation, the removal efficiency of $COD_{Cr}$, SS, TN and TP were 94.3%, 99.9%, 69.4%, and 74.6%, respectively. There was no significant effect of microbial activity after the maintenance cleaning using 200 mg/L of NaOCl. Membrane filtration for the treatment of municipal wastewater was performed for longer than 9 months without chemical recovery cleaning.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1255-1257
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• 1997

In order to obtain key technologies for a kW class internal humidifying proton-exchange-membrane fuel cell (PEMFC) a single cell with a large electrode area has been designed and manufactured and the performance of large area membrane/electrode assemblies (MEAs) has been evaluated by using the single cell. A small area MEA made of commercial E-TEK electrode and Nafion 117 membrane showed a performance of 0.7V, $300mA/cm^2$ whereas large area MEA made of catalyst layer on carbon support and Nafion 117 showed a lower performance. To improve the performance of large MEA direct coating of catalyst was carried out on the membrane using a screen printer.