• 상하수도학회지
• /
• 제19권1호
• /
• pp.47-52
• /
• 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.

• 한국산학기술학회논문지
• /
• 제16권9호
• /
• pp.6403-6410
• /
• 2015

의료용 고분자 PLGA는 높은 생체적합성, 생분해성, 기계적 특성, 생체안정성을 가지고 있으며, 단량체 수량을 조절함으로서 분해기간을 조절할 수 있는 장점이 있다. 본 논문에서는 상전이법을 이용하여 제조된 분자량과 L/D 타입 구성비가 다른 PLGA 멤브레인들을 인산완충생리식염수 하에서 멤브레인의 분자량과 용액의 온도 조건에 따른 생분해 특성을 유추하기 위하여 질량 변화와 용액의 pH값 측정하였으며, DSC와 실사현미경을 이용하여 Tg와 표면구조의 변화을 파악하였다. PLGA의 분자량이 증가할수록 가수분해속도는 기하급수적으로 감소하고 있으며, L/D 타입 구성비에 따라 분해속도와 용액 pH변화의 차이가 크게 나타났다.

• 동의생리병리학회지
• /
• 제33권1호
• /
• pp.25-30
• /
• 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.

• 대한방사성의약품학회지
• /
• 제7권2호
• /
• pp.79-84
• /
• 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
• /
• 제32권11호
• /
• pp.989-997
• /
• 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.