• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.47-52
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• 2005

This study was conducted to evaluate the performance of submerged hollow fiber MF processes to treat secondary wastewater for water reuse. Specifically, membrane productivity and filtrate water quality were investigated under various operating conditions (i.e. flux, recovery, and backwash rate) at pilot-scale. Membrane fouling became more severe with increasing flux and recovery, suggesting that low flux operation (< 25 LMH) was desirable. At high flux operating(> 37.5 LMH), increasing backwash rate showed only limited success. The biofouling, quantified by PEPA and BFHPC, was also significant in wastewater reclamation, and biogrowth control by chlorine, were necessary to improve membrane productivity. Filtrate water qualities are in good compliance with water reuse regulations regardless of operating conditions (flux, recovery and backwash rate). Particle (e.g. turbidity) removal ranged from 89 to 98%, while only 11 to 21% of organics (e.g. NPDOC) were removed by MF membrane. Only small improvement in biostability (e.g. AOC) was achieved by MF system, and thus, without post disinfection, significant microorganisms might be present in the filtrate due to regrowth. Lastly, in order to further investigate pathogen removal, controlled microbial challenge tests were performed by monitoring Giardia, Cryptosporidium, bacteria and virus, and showed relatively good microbial removal.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6403-6410
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• 2015

Medical polymer PLGA is biocompatible, biodegradation, mechanical characteristic and biostability, and the degradation time can be adjust by controlling the number of monomer. In this paper, PLGA membranes have different composition ratio by L/D type was prepared by phase transition method. And the PLGA membrane in phosphate buffered saline(PBS) at the different test temperatures for different periods of time to examined for change in mass and measured the pH of degradation media. Measurement of Tg and surface structure was performed using a DSC and Stereoscopic microscope. As the molecular weighter increase, hydrolysis rate was decrease in geometrical progression. According to the composition ratio by L/D type, degradation rate and the change of pH are large.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.1
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• pp.25-30
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• 2019

This study was aimed to examine the synergetic effects of photochemopreventive external agents composed of inorganic ZnO and esculetin. Zinc oxide (ZnO) is widely used in sunblocks because of its excellent biostability and little toxicity. Esculetin derived from Citrus Peel has an anti-oxidative effect. We made the hollow-shaped ZnO microsphere (MS), soaked it with esculetin (EZnO). We used SKH-1 mice to measure the photodamaging effects of UVB. The mice were divided into five groups as follows; UVB nontreated group (N), vehicle (C), esculetin (E), ZnO MS (ZnO), esculetin + ZnO MS(EZno) group. Each group of samples was topically applied to the dorsal skins before the UVB irradiation. The changes of collagen fibers in the skin tissues were observed by H & E staining and Van Gieson staining. The expression of mast cells in skin tissue was observed by immunohistochemical staining of tryptase present in the mast cell granules. Expression of inflammatory cytokines such as TNF-${\alpha}$, IL-$1{\beta}$, and MMP-9, which plays an essential role in wrinkle formation, was measured by RT-PCR. Interestingly, the composition of collagen fibers was better in the EZnO applied group than in the E or ZnO group. Moreover, mast cell expression and the expression of TNF-${\alpha}$, IL-$1{\beta}$, and MMP-9 mRNA were markedly suppressed in the EZnO group, indicating that the synergetic effects of esculetin and ZnO were excellent.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.2
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• pp.79-84
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• 2021

Radiopharmaceuticals are important for tumor diagnosis and therapy. To deliver a radiotracer at the desired target excluding non-targeted tissues is difficult The development of a targeted tracer that has a good clearance profile while maintaining high biostability and biocompatibility is key to optimizing its biodistribution and transport across biological barriers. Improving the hydrophilicity of radiotracers by PEGylation can reduce serum binding, allowing the tracer to circulate without retention and reducing its affinity for non-targeted tissues. In this study, we synthesized a new benzamido tracer (SnBz-PEG₃₆) with the introduction of a low molecular weight polyethylene glycol unit (PEG₃₆, ~2,100 Da). The tumor targeting efficiency and biodistribution of [¹³¹I]-Bz-PEG₃₆ or radiotracer-loaded liposomes were evaluated after their administration to normal mice or mouse tumor models including CT26 (xenograft) and 4T1 (xenograft and orthotopic). Most of the radiotracer was cleared out rapidly (1-24 h post-administration) through the kidney and there was little tumor uptake.

• Journal of Chest Surgery
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• v.32 no.11
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• pp.989-997
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• 1999

Background: Calcific degeneration is the major cause of clinical failure of glutaraldehyde (GA) crosslinked bioprosthetic tissues implanted in the body and necessitates the reoperation or causes death. Surface modification of biologic tissues using sulfonated polyethyleneoixde (PEO-SO3) has been suggested to significantly enhance blood compatibility, biostability and calcification-resistance by means of the synergistic effect of highly mobile and hydrophilic PEO chains and electrical repulsion of negatively charged sulfonate groups. This study was designed to evaluate the anticalcification effect of surface-modification of biologic arteries by direct coupling of PEO-SO3 after GA fixation and changes of calcification according to the implantation period through the quantitative investigation of the deposited calcium and phosphorous contents of the biologic arterial tissues in the canine circulatory implantation model. Material and Method: Total of 16 fresh canine carotid arteries were harvested from eight adult dogs and divided in to GA group(n =8) and PEO-SO3 group(n=8). Sulfonation of diamino-terminated PEO was performed using propane sultone. Canine carotid arteries were only crosslinked with 0.65% GA solution in GA group and modified by direct coupling 5% PEO-SO3 solution after GA crosslinkage for 2 days and stabilized by NaBH4 solution for 16 hours in PEO-SO3 group. In both groups the resected segment of bilateral carotid arteries were reconstructed. Reconstructed segments of the two groups were analysed the quantities of calcium and phosphorous contents after 3(n=4) and 6(n=4) weeks in vivo. Result: After implantation of 3 seeks, PEO-SO3 group showed significantly less depositions.