• Corrosion Science and Technology
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• 제9권6호
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• pp.331-337
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• 2010

This study compared the macro and micro electrochemical characteristics at the local area of welding metal on dissimilar welding parts for type 304 stainless steel (SS) and type 316L SS. The materials are used for double wall gas pipe of duel fuel engine for a ship. The various potentiodynamic experiments were performed several times in 10% ${H_2C_2O_2}{\cdot}{H_2O}$ solution using macro and micro methods, respectively. The micro electrochemical experiments conducted to resolve at local area on cross-section of dissimilar welding materials by micro-droplet cell device. The micro-droplet cell techniques can be used almost electrochemical experiments to resolve corrosion characteristics of the limited electrode area of the metallic surface between wetted spot of working electrode and tip of sharpened capillary tube. The results of macro electrochemical experiments show that resistance of active dissolution reaction at welding zone was high due to low current density by formation of passivation protection film at passive region. According to the micro electrochemical experiment, the corrosion current density of welding zone and bond zone were relatively high.

• Molecules and Cells
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• 제41권2호
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• pp.93-102
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• 2018

Discoidin domain receptor 1 (DDR1) is involved in tumorigenesis and angiogenesis. However, its role in lymphangiogenesis has been unknown. Here, we tested whether downregulation of DDR1 expression by miR-199a/b can suppress lymphangiogenesis. We also aimed to identify miRNA target site(s) in the 3' untranslated region (UTR) of DDR1. Transfection with miR-199a/b-5p mimics reduced expression of DDR1 and tube formation in primary human dermal lymphatic endothelial cells, whereas miR-199a/b-5p inhibitors showed the opposite effects. Critically, injection of miR-199a/b-5p mimics suppressed DDR1 expression and lymphangiogenesis in a corneal alkali-burn rat model. The three well-conserved seed matched sites for miR-199a/b-5p in the DDR1 3'-UTR were targeted, and miRNA binding to at least two sites was required for DDR1 inhibition. Our data suggest that DDR1 promotes enhanced lymphangiogenesis during eye injury, and miR-199a/b-5p suppresses this activity by inhibiting DDR1 expression. Thus, this miRNA may be useful for the treatment of lymphangiogenesis-related eye diseases.

• 한국항해항만학회지
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• 제35권5호
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• pp.365-370
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• 2011

최근 지구 온난화와 더불어 급격한 기후 변화 등으로 여름철 주간 냉방 수요가 급격히 증가하고 있다. 이에 따른 전력 수요량 또한 증가하고 있다. 이런 이유로 세계적으로 에너지 이용 효율 향상에 대한 관심이 높아지고 있고, 최근 국내 및 국외의 축냉시스템을 이용한 주간 전력 피크값을 최소화 하는 연구개발과 실제 적용 사례가 늘어나고 있다. 빙축열시스템의 경우 그 경제적 효과가 높아 그 관심이 높아지고 있는 추세이다. 축냉시스템은 주간 냉방에 사용하는 냉열을 야간에 만들어 탱크에 저장해 두었다가 그것을 낮에 이용함으로써, 갑작스런 부하 증가에 적절히 대응할 수 있는 등 여러 가지 장점을 갖고 있다. 본 실험에서는 슬러리아이스 생성을 위해 냉각표면에서 생성된 슬러리아이스를 분리시키기 위해 유체보다 밀도가 낮은 역전유동 물질을 삽입하여 역전 유동층을 형성하였으며, 역전유동층의 유동에 의해 관군으로 구성되어 있는 냉각튜브 표면에 빙부착이 심화되기 전에 얼음 입자를 분리시켜 수 내지 수십 미크론 단위의 슬러리아이스를 생성하도록 하였다.

• 한국산학기술학회논문지
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• 제16권9호
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• pp.5795-5801
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• 2015

식생활의 향상 및 다양화로 신선한 제품에 대한 요구가 증가하고 있으며, 이에 따라 냉장 및 냉동식품의 저온유통 또한 점차 증가되고 있다. 현재 냉동산업에는 주로 R134a 냉매가 사용되고 있으며 GWP(Global Warming Potential)가 1300으로써 매우 높아 지구온난화에 영향을 미친다. 이를 대체하기 위한 냉매로써 R1234yf 냉매가 있으며, GWP는 4로써 매우 낮다. 냉동탑차 냉장시스템에 사용되는 증발기는 저온조건에서 작동되기 때문에 서리가 형성되어 시스템의 성능을 급격히 감소시킨다. 따라서, 본 연구에서 R134a와 R1234yf 냉매를 작동유체로 사용한 증발기의 성능을 착상조건 하에서 다양한 운전조건으로 분석하였다. 해석결과, 서리성장 조건에서 공기측 입구온도, 상대습도, 증발온도 변화에 대하여 R134a 증발기의 성능이 R1234yf 증발기보다 더욱 민감하게 나타났으며 서리의 성장 또한 R134a 증발기가 더 크게 나타났다.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.416-424
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• 2018

Microstructure of oxide formed on Zr-Nb-Sn tube sample was intensively examined by scanning transmission electron microscopy after exposure to simulated primary water chemistry conditions of various concentrations of Zn (0 or 30 ppb) and dissolved hydrogen ($H_2$) (30 or 50 cc/kg) for various durations without applying desirable heat flux. Microstructural analysis indicated that there was no noticeable change in the microstructure of the oxide corresponding to water chemistry changes within the test duration of 100 days (pretransition stage) and no significant difference in the overall thickness of the oxide layer. Equiaxed grains with nano-size pores along the grain boundaries and microcracks were dominant near the water/oxide interface, regardless of water chemistry conditions. As the metal/oxide interface was approached, the number of pores tended to decrease. However, there was no significant effect of $H_2$ concentration between 30 cc/kg and 50 cc/kg on the corrosion of the oxide after free immersion in water at $360^{\circ}C$. The adsorption of Zn on the cladding surface was observed by X-ray photoelectron spectroscopy and detected as ZnO on the outer oxide surface. From the perspective of $OH^-$ ion diffusion and porosity formation, the absence of noticeable effects was discussed further.

• The Plant Pathology Journal
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• 제32권5호
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• pp.460-468
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• 2016

To study the control of postharvest decay caused by Colletotrichum gloeosporioides and Penicillium expansum, gamma irradiation alone or in combination with fumigation was evaluated to extend the shelf life of apples in South Korea. An irradiation dose of 2.0 kGy resulted in the maximum inhibition of C. gloeosporioides and P. expansum spore germination. The gamma irradiation dose required to reduce the spore germination by 90% was 0.22 and 0.35 kGy for C. gloeosporioides and P. expansum, respectively. Microscopic observations revealed that when the fungal spores were treated with gamma irradiation (4.0 kGy), conidial germination was stopped completely resulting in no germ tube formation in C. gloeosporioides. Treatment with the eco-friendly fumigant ethanedinitrile had a greater antifungal activity against C. gloeosporioides and P. expansum in comparison with the non-treated control under in vitro conditions. The in vitro antifungal effects of the gamma irradiation and fumigation treatments allowed us to further study the effects of the combined treatments to control postharvest decay on stored apples. Interestingly, when apples were treated with gamma irradiation in combined with fumigation, disease inhibition increased more at lower (< 0.4 kGy) than at higher doses of irradiation, suggesting that combined treatments reduced the necessary irradiation dose in phytosanitary irradiation processing under storage conditions.

• 한국산학기술학회논문지
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• 제10권3호
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• pp.613-619
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• 2009

SHI-1909를 초산과 TNBS에 의해 rat에 유발된 염증성 대장염 모델에서 5일 동안 경구 투여 하여 대조약인 프레드니솔론과 그 치료 효능을 비교 조사하였다. 7% 초산과 5% TNBS 용액을 polyethylene 튜브로 rat의 항문에 점적하여 염증성 대장염을 유발하였으며 점적 후 초산과 TNBS 대조군은 말단의 대장부위에서 궤양과 염증 증상 같은 병적인 소견을 보여 염증성 대장염이 잘 유발되었음을 확인할 수 있었다. 약물의 투약기간 중 염증 치유 변수인 실험동물의 중량과 식이 섭취량 변화를 관찰하였으며 실험이 종료된 후에는 실험동물을 희생시킨 후 대장의 길이와 궤양, 병적인 소견을 조사하였다. SHI-1909의 투여는 중량변화와 식이 섭취량 등에서 대조약과 필적할 만한 결과를 나타내었으며 특히 대장의 손상 정도 평가에서 대조약물인 프레드니솔론보다도 더 우수한 효과를 나타내었다. 이러한 결과로부터 SHI-1909는 IBD의 치료에 가능성이 있는 치료 약물이 될 수 있을 것으로 사료된다.

• 한국동물학회지
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• 제24권2호
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• pp.65-75
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• 1981

Gerris paludum의 精子形成 동안의 尖體形成에 대한 연구를 요약하면 다음과 같다. 1. Golgi體는 精母細胞의 초기단계에서 細胞質에 산재되어 있다가 서로 융합하여 囊 胚形을 하며 이들이 모여서 감수분열 전기에는 몇 개의 큰 Golgi體群을 형성하는데, 이들은 결국 精細胞에 균등히 분포된다. 2. 精子完成에서 acroblast는 처음에 하나의 큰 胞로 나타나다가, 그 내부에서 尖體顆粒이 分化된 후, acroblast는 顆粒에서 分離되어 결국 tail filament를 따라 사라진다. 3. 尖體는 mitochondrial derivatives의 반대편인 核 전면부로 이동한 후, two zones 즉 core와 sheath로 分化된다. 4. Basal bodies와 tip은 모두 sheath에서 由來한다. Basal bodies는 sheath의 基部에서 발생해서 尖體가 伸長되고 좁아짐에 따라 점차로 尖體의 基部를 싸기 시작하여 결국 완전히 둘러싸게 되며, 分化된 tip은 core의 前端部에 인접해서 나타나지만 sheath와 뚜렷이 연결되어 있다. 5. 分化된 tip은 basal bodies보다 앞서서 伸長한다. Basal bodies는 精細胞 후기에 하나의 顆粒으로 융합하지 않고 서로 연결된 wtin-tubes로 나타나며, sperm bundle에서는 basal bodies group을 형성한다.

• 대한종양외과학회지
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• 제14권2호
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• pp.95-101
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• 2018

Purpose: The standard treatment of esophageal cancer is the Ivor-Lewis operation, which consists of an abdominal phase involving gastric tube formation, and a chest phase involving esophagectomy and anastomosis. We aimed to report our experience of performing thoracic esophagectomy with the laparoscopic gastric pull up (LGPU) technique and its surgical outcomes. Methods: Clinicopathologic data and short-term surgical outcomes of 14 patients who underwent LGPU for thoracic esophageal cancer from August 2008 to May 2016 were retrospectively reviewed. Results: Mean age of the patients was 62.3 years and mean body mass index was $21.7kg/m^2$. Eleven patients had medical comorbidities. Patients' mean American Society of Anesthesiologists score was 2. Mean operation time was 428.5 minutes, with the mean abdominal operation time being 138.9 minutes. There was no open conversion case. Three patients had pneumonia, three patients had surgical site infection, and one patient had subcutaneous emphysema within 30 days after surgery. One patient had minor anastomosis site leakage. There was one 30-day mortality case. One patient with postoperative aspiration pneumonia developed acute respiratory distress disease, and died due to sepsis. Mean postoperative intensive care unit stay was 3.5 days, and mean postoperative hospital stay was 20.6 days. Nasogastric tubes were removed on average at 3.4 days, and mean oral intake time was 3.4 days. Conclusion: If the gastrointestinal surgeon has extensive experience in laparoscopic procedures, LGPU will be a safe and feasible technique for thoracic esophagectomy in patients with intrathoracic esophageal cancer.

• Biomolecules & Therapeutics
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• 제27권1호
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• pp.117-125
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• 2019

Mebendazole (MBZ), a microtubule depolymerizing drug commonly used for the treatment of helminthic infections, has recently been noted as a repositioning candidate for angiogenesis inhibition and cancer therapy. However, the definite anti-angiogenic mechanism of MBZ remains unclear. In this study, we explored the inhibitory mechanism of MBZ in endothelial cells (ECs) and developed a novel strategy to improve its anti-angiogenic therapy. Treatment of ECs with MBZ led to inhibition of EC proliferation in a dose-dependent manner in several culture conditions in the presence of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) or FBS, without selectivity of growth factors, although MBZ is known to inhibit VEGF receptor 2 kinase. Furthermore, MBZ inhibited EC migration and tube formation induced by either VEGF or bFGF. However, unexpectedly, treatment of MBZ did not affect FAK and ERK1/2 phosphorylation induced by these factors. Treatment with MBZ induced shrinking of ECs and caused G2-M arrest and apoptosis with an increased Sub-G1 fraction. In addition, increased levels of nuclear fragmentation, p53 expression, and active form of caspase 3 were observed. The marked induction of autophagy by MBZ was also noted. Interestingly, inhibition of autophagy through knocking down of Beclin1 or ATG5/7, or treatment with autophagy inhibitors such as 3-methyladenine and chloroquine resulted in marked enhancement of anti-proliferative and pro-apoptotic effects of MBZ in ECs. Consequently, we suggest that MBZ induces autophagy in ECs and that protective autophagy can be a novel target for enhancing the anti-angiogenic efficacy of MBZ in cancer treatment.