• Clean Technology
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• v.27 no.4
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• pp.359-366
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• 2021

Halloysite nanotubes (HNTs), the multiwalled clay mineral with the composition of Al₂Si₂O₅(OH)₄·nH₂O, have been highlighted as a low-cost adsorbent for the removal of dyes from wastewater. Although a powder of halloysite presents a high specific surface area, forming media are significantly considered due to sludge-clogging induced by the water-bound agglomeration. However, higher firing temperature to achieve the structural durability of the media and lower utilization rate due to longer penetration depth into the media act as hurdles to increase the dye-adsorption capacity. In this work, the retention of the adsorption capacity of halloysite was evaluated with methylene blue solution after the heat treatment at 750 ℃. In order to improve the utilization rate, tubular media were fabricated by extrusion. The images taken by transmission electron microscopy show that HNTs present excellent structural stability under heat treatment. The HNTs also provide superb capacity retention for MB adsorption (93%, 18.5 mg g^-1), while the diatomite and Magnesol^® XL show 22% (7.65 mg g^-1) and 6% (11.7 mg g^-1), respectively. Additionally, compositing with lignin enhances adsorption capacity, and the heat treatment under the hydrogen atmosphere accelerates the adsorption in the early stage. Compared to the rod-type, the tubular halloysite media rapidly increases methylene blue adsorption capacity.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.2
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• pp.105-113
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• 2003

The pyrolysis for production of hydrogen and high quality carbon black from natural gas were studied. The reactivities in tubular reactor and FVR(free volume reactor) for the methane pyrolysis were compared, in order to prevent the formation of undesirable carbon product such as pyrocarbon, the FVR was designed. The hydrogen yield and the formation of carbon black from methane pyrolysis in this reactor were investigated at temperature range between 1443 and 1576K. From the result of TEM (transmission electron microscopy) analysis, it was confirmed that the CFC(catalytic filamentous carbon) was formed without pyrocarbon.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.45-47
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• 2002

Although Dacron and ePTFE have most widely been used for artificial vascular grafts, these materials cannot be used for small-diameter grafts (l.D.<6mm) due to thrombotic occlusion. To overcome this limitation, a small-diameter vascular graft was developed with stem cell and tissue engineering method. Autologous bone marrow stem cells were cultured and seeded onto small-diameter (4mm) collagen tubular matrices. The matrices were anastomosed to carotid arteries in canine models. Prior to implantation, histological and electron microscopical examination revealed stem cell adhesion and growth on the matrices. Angiography indicated that the vascular grafts maintained patent for 8 weeks. Histological examination showed the regeneration of endothelium, media and adventitia in the grafts. This study may allow us to step forward to the development of tissue-engineered small-diameter vascular graft appropriate for clinical applications.

• Membrane Journal
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• v.24 no.2
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• pp.123-135
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• 2014

The effects of pH, saturated oxygen, and back-flushing media were investigated in hybrid process of tubular ceramic microfiltration and $TiO_2$ photocatalyst-loaded PES (polyethersulfone) beads for advanced drinking water treatment, and compared results of water, nitrogen, or oxygen back-flushing in the viewpoints of membrane fouling resistance ($R_f$), permeate flux (J) and total treated water ($V_T$). $R_f$ decreased, and J and $V_T$ increased as decreasing pH. Turbidity treatment efficiencies were similar at water or nitrogen back-flushing independent of pH, but DOM (dissolved organic matter) treatment efficiency did not have a trend at water back-flushing. $R_f$ at NBF (no back-flushing) with SO (saturated oxygen) was the lower than that at NBF without SO. Also, the DOM treatment efficiency at NBF with SO was the lower than that at NBF without SO. It happened because OH radicals produced by reaction of SO and photocatalyst could dilute with water inside the module. The DOM treatment efficiency of gas back-flushing showed the larger than that of water back-flushing at back-flushig period 10 min. It proved that the adsorption or photo-oxidation of PES beads could be activated by the more effective bead-cleaning of gas back-flushing than water back-flushing.

• Journal of Chest Surgery
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• v.9 no.2
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• pp.276-286
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• 1976

Coarctation of the aorta is an important congenital cardiovascular defect,. which occurs in a significant number of persons. The basic anatomic defect is a localized deformity of the media, manifested by two types of strictures in the aorta: "true" coarctation and tubular hypoplasia. The zone of coarctation is characteristically located distal to the origin of left subclavian artery at or just beyond the insertion of the ligamentum arteriosum. It shortens life if untreated, but it can be corrected to render the patient functionally normal. Here we have a 2-year operative experiences with 3 cases of the aortic coarctation, two of hypoplastic type and one of postductal type, at age of 17 to 19 year old Korean, operated in 1965 and l968 at the National Medical Center. The purposes of this report are to describe the immediate and late effect of surgery, histopathologic bases and the rarity of this lesions in Korea.

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.257-267
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• 1996

Diabetes mellitus is associated with a wide range of pathophysiologic changes in the kidney. This study was designed to examine the mechanisms by which glucose modulates the expression of polarized membrane transport functions in primary cultured rabbit renal proximal tubule cells. Results are as follows: The rate of 30 minute $Rb^{+}$ uptake was significantly higher($137.76{\pm}5.40%$) in primary renal tubular cell cultures treated with 20 mM glucose than that of 5 mM glucose. Not the level of mRNA for the ${\alpha}$ subunit of Na, K-ATPase but that of ${\beta}$ subunit was elevated in primary cultures treated with high glucose. The initial rate of methyl-${\alpha}$-D-glucopyranoside(${\alpha}$-MG) uptake was significantly lower($71.91{\pm}3.02%$) in monolayers treated with 20 mM glucose than that of 5 mM glucose. There was a tendency of an increase in phlorizin binding site in cells treated with 5 mM glucose. However, 3-O-methyl-D-glucose(3-O-MG) uptake was not affected by glucose concentration in culture media. TPA inhibited $Rb^{+}$ uptake by $63.61{\pm}1.94\;and\;45.80{\pm}1.36%$ and ${\alpha}$-MG uptake by $48.54{\pm}3.69\;and\;41.87{\pm}6.70%$ in the cells treated with 5 and 20 mM glucose, respectively. Also TPA inhibited mRNA expression of Na/glucose cotransporter in cells grown in 5mM glucose medium. cAMP significantly stimulated ${\alpha}$-MG uptake by $114.65{\pm}5.70%$ in cells treated with 5mM glucose, while it did not affect ${\alpha}$-MG uptake in cell treated with 20 mM glucose. However, cAMP inhibited $Rb^{+}$ uptake by $76.69{\pm}4.16\;and\;66.87{\pm}2.41%$ in cells treated with 5 and 20 mM glucose, respectively. In conclusion, the activity of the renal proximal tubular Na,K-ATPase is elevated in high glucose concentration. In contrast, the activity of the Na/glucose cotransport system is inhibited. High glucose may in part affect the activity of the Na,K-ATPase and the Na/glucose cotransport system by controlling the protein kinase C and/or A signal transduction pathway in primary cultured renal proximal tubule cells.

• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.85-93
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• 1995

In order to examine the effect of testosterone of the cell growth, using a primary rabbit kidney proximal tubule cell culture system, we observed the effect of 3 growth factors and testosterone supplementation on the growth of primary rabbit kidney proximal tubule cells in the serum-free medium. 1 nM of testosterone showed a potentiation of the effect on the growth of the proximal tubule cell in serum-free medium, but higher concentration (>10 nM) of testosterone indeed inhibited the growth. In the absence of hydrocortisone as a growth supplement in serum-free medium, testosterone caused to potentiate the growth of the cell. In the presence of hydrocortisone, testosterone also potentiated the grwoth of the proximal tubule cells. According to the Northern analysis, testosterone increased significantly the level of ${\beta}-actin$ mRNA in proximal tubular cells of rabbit kidney. Consequently we may suggest that growth stimulatory effect of testosterone on the primary rabbit kidney proximal tubule cell in serum-free and hormonally defined media ascribed to increase the synthesis of ${\beta}-actin$, which is an important protein consisting of cellular microfilament.

• Journal of Nutrition and Health
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• v.53 no.1
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• pp.1-12
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• 2020

Purpose: Diabetic nephropathy is one of the most important diabetic complications prompted by chronic hyperglycemia, characterized by glomerulosclerosis, tubular fibrosis, and it eventually causes kidney failure. Nobiletin is a polymethoxyflavone present in tangerine and other citrus peels, and has anti-cancer and anti-inflammatory effects. This study investigated the effects of nobiletin on glomerular fibrosis through inhibition of the transforming growth factor (TGF)-β1-Src-caveolin-1 pathway. Methods: Human renal mesangial cells (HRMC) were incubated in media containing 33 mM glucose with or without 1-20 uM nobiletin for 3 day. The cellular expression levels of fibrogenic collagen IV, fibronectin, connective tissue growth factor (CTGF), TGF-β1, Src and caveolin-1 were all examined. In addition, TGF-β1, Src and caveolin-1 proteins were screened to reveal the relationship among TGF-β1-Src-caveolin-1 signaling in glomerular fibrosis. Results: High glucose promoted the production of collagen IV, fibronectin and CTGF in HRMC, which was inhibited in a dose dependent manner by 1-20 uM nobiletin. The Western blot data showed that high glucose elevated the expression of TGF-β1, Src, caveolin-1 and Rho GTPase. When nobiletin was treated to the HRMC exposed to high glucose, the expression of TGF-β1-Src-caveolin-1 was dampened. Finally, TGF-β1-Src-caveolin-1 signaling pathway was activated in high glucose-exposed HRMC, and such activation was encumbered by nobiletin. Conclusion: These result demonstrated that nobiletin blunted high glucose-induced extracellular matrix accumulation via inhibition of the TGF-β1-Src-caveolin-1 related intracellular signaling pathway. Nobiletin may be a potent renoprotective agent to counteract diabetes-associated glomerular fibrosis that leads to kidney failure.

• Journal of Gastric Cancer
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• v.5 no.3 s.19
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• pp.191-199
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• 2005

Background: Though infections of Helicobacter pylori (H. pylori) are closely associated with activation of host angiogenesis, the underlying mechanisms, as well as the strategy for its prevention, have not been identified. Here, we investigated a causal role of H. pylori infection in angiogenesis of gastric mucosa and a potent inhibitory effect of a gastric proton pump inhibitor (PPI) on the gastropathy. Materials and Methods: A comparative analysis of CD 34 expression in tissues obtained from 20 H. pylori-associated gastritis and 18 H. pylori-negative gastritis patients was performed. Expression of $HIF-1{\alpha}$ and VEGF were tested by using RT-PCR. To evaluate the direct effect of H. pylori infection on differentiation of endothelial HUVEC cells, we carried out an in vitro angiogenesis assay. Results: H. pyfori-associated gastritis tissues showed significantly higher density of $CD34^+$ blood vessels than did H. pylori-negative gastritis tissues, and the levels were well correlated with expressions of $HIF-1{\alpha}$. Conditioned media from H. pylori-infected gastric mucosal cells stimulated a tubular formation of HUVEC cells. We also found a significant inhibitory effect of PPI, an agent frequently used for H. pylori eradication, on H. pylori-induced angiogenesis. This drug effectively inhibited the phosphorylation of MAP kinase ERK1/2, which is a principal signal for H. pylori-induced angiogenesis. Conclusion: The fact that PPls can down-regulate H. pylori-induced angiogenesis suggest that anti-angiogenic treatment using PPI may be a preventive approach for H. pylori-associated carcinogenesis.