• Korean Journal of Veterinary Research
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• v.39 no.1
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• pp.220-225
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• 1999

The aim of these experiments was to investigate the effects of bovine oviduct epithelial cells (OEC) derived from different segments to bind sperm binding and maintain their motility in vitro. In experiment 1, the number of sperm attached to OEC derived from isthmus or ampulla, the motility of unattached sperm during co-culture and fertilizing ability were assessed. In experiment 2, heparin treated sperm (hsp) or no treated sperm (nsp) were used to evaluate OEC binding ability of capacitated sperm. In experiment 1, regardless of their origin, approximately 65% of the sperm were attached to OEC within 2h. From 6h of co-culture, the numbers of unattached sperm on ampullary OEC were significantly higher than those on isthmic OEC (p<0.005). From 12h of co-culture, the motility of unattached sperm on isthmic OEC were significantly higher than those on ampullary OEC(p<0.05). The cleavage rate of oocytes inseminated on OEC derived from isthmic segment was also significantly higher than those from ampullary segment (p<0.01). In experiment 2, the numbers of unattached hsp on OEC were significantly higher than those of controls (p<0.01), between 2-24h examination. From 12h of co-culture, the motility of unattached nsp were significantly greater than those of hsp (p<0.01). These results show that bovine OEC derived from the isthmus play more important role(s) for sperm binding, maintaining motility and fertilization in vitro than those from the ampulla, and heparin induced capacitation may change sperm binding ability on OEC in vitro.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.2
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• pp.160-166
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• 2004

Combustion using oxygen enriched air is known as a technology which can increase flame stability as well as thermal efficiency due to improving the burning rate. Lift-off, blowout limit and flame length were examined as a function of jet velocity, coflow velocity and OEC(Oxygen Enriched Concentration). Blowout limit of the flame below OEC 25% decreased with increase of coflow velocity, but the limit above OEC 25% increased inversely. Lift-off height decreased with increase of OEC. In particular, lift-off hardly occurred in the condition above OEC 40%. Flame length of the flames above OEC 40% was increased until the blowout occurred. Great flame stability was obtained since lift-off and blowout limit significantly increased with increase of OEC.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.326-331
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• 2003

Combustion using oxygen enriched air is known as a technology which can increase flame stability as well as thermal efficiency due to improvement of the burning rate. Lift-off, blowout limit and flame length were examined as a function of jet velocity, coflow velocity and OEC(Oxygen Enriched Concentration). Blowout limit of the flame below OEC 25% decreased with coflow velocity, but the limit above OEC 25% increased inversely. Lift-off height decreased with increase of OEC. Especially lift-off hardly occurred in the condition above OEC 40%. Flame length of the flames above OEC 40% was increased until the blowout occurred. Flame stability became improved since lift-off and blowout limit increased much with increase of OEC.

• Journal of Embryo Transfer
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• v.13 no.3
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• pp.227-233
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• 1998

The aim of these experiments was to investigate the effects of oviduct epithelial cells on bovine in vitro fertilization. Oviduct epithelial cell monolayers (OEC) on the 4-well dish were prepared according to general procedures. Monolayers were formed within 5days. The medium for OEC culture (TCM199 with 10% FBS) was replaced with IVF-TALP 2h before each experiment. Macromolecules/proteins from oviductal conditioned medium (OM) were recovered by ultrafiltration, which desalted and concentrated macromolecules greater than 5kDa, and this OM were added to W medium (experiment 1). The cleavage rate in OM+OEC group was significantly higher than in OM group (p〈0.01). In this experiment 2, oocytes were inseminated on OEC with sperm which had been pre-incubated with OEC for 0 or 4h before insemination. In this experiment, oocytes were exposed to sperm only 8 h for clarifying the effect. After insemination, oocytes were cultured in CRlaa. At 42 h post insemination, oocytes were denuded and examined for evidence of cleavage. The cleavage rates of oocytes which were inseminated with OEC treated sperm for 4 h were significantly higher than those of the other group (p〈0.01). In conclusion, sperm released from OEC have more fertilizing ability than those before attachment.

• Rapid Communication in Photoscience
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• v.3 no.2
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• pp.35-37
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• 2014

PEC (photoelectrochemical) water splitting for $O_2/H_2$ production is one of the promising but difficult way to utilize solar energy. Among photocatalytic materials for PEC water oxidation, $BiVO_4$ (Eg = 2.4 eV) has been recently intensively studied since it has various advantageous properties. But its maximum efficiency has not been realized owing to kinetic factors - slow water oxidation at surface & insufficient stability. These problems can be simultaneously solved by application of oxygen evolution catalyst (OEC) such as $CoO_x$, Co-Pi, $IrO_x$ etc. Herein we report the first successful application of $NiFeO_x$ OEC on $BiVO_4$, showing good performance compared to other effective OEC applied on $BiVO_4$ under basic conditions. The enhanced activity of OEC loaded $BiVO_4$ has been supported by the surface charge separation efficiency and electrochemical impedance studies.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.2
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• pp.223-229
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• 2004

Combustion using oxygen enriched air is known as a technology which can increase thermal efficiency due to increase of the flame temperature. Flame shapes, schlieren photos, OH radical chemiluminescence and local flame temperature were examined as a function of OEC(Oxygen Enriched Concentration) in a coaxial non-premixed jet. With increase of OEC, flame length and width decreased, but its brightness increased significantly, and the size of vortices in the flame also increased. Especially, the reaction around the flame surface became active. The strong OH intensity appeared to be made and moved from middle stream to upper one with increase of OEC, which shows combustion reaction in the upper stream becomes more dominant In addition, the temperature distributions of the flames showed similar tendency with OH radical intensities. A flame with high temperature and strong stability was obtained with increasing OEC of the coflow.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.113-115
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• 2012

안드로이드 앱의 불법 복제를 방지하고자 기존에 온라인 실행(Online Execution Class: OEC) 또는 앱을 암호화된 상태로 배포하여 실행 시에 적법한 사용자만이 암호를 복호화하여 실행이 가능하도록 하는 방법들이 있다. 하지만 스마트폰이 저전력과 저사양인 점을 고려할 때, 위에 방법은 스마트폰의 보안을 보장할 수 있지만 성능 면에서 부담이 된다. 본 논문에서 OEC를 암호화하여 보안 수준을 높이고 개발자에게 보안 수준을 선택할 수 있게 하여 환경에 맞추어 안전을 유지할 수 있도록 시스템 설계를 제안한다.

• Environmental and Resource Economics Review
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• v.15 no.2
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• pp.201-245
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• 2006

We applied general equilibrium model to analysis the economic impact of international emission trading by sector and the efficiency of the Convention to study whether Climate Change Convention satisfy the efficiency. We divided the world as 4 groups : USA, OECD members w/o USA (OEC), Former Soviet Union (FSU) and Developing countries (DEV). Compared to no trading, global trading would accomplish the same environmental effect with less cost as much as 97.8 billion$, which is the surplus of trading. However, half of it is taken by USA and 20% by OEC. FSU and DEV have only 18% and 10%. This result suggest the two things. First, the emission trading is effective as far as the participation of developing countries are guaranteed. If they do not take part in the coalition and emit the leakage, it may threaten the stability of the international trading coalition. Second, we found the logical ground of the side payment for developing countries. The permit buying countries take more share of the surplus under the emission trading, while the energy sector of developing countries shrinks to sell permits, which may adversely affect to economic growth of the countries. Therefore, the Annex-I countries need to provide side payment to lead the participation of the developing countries.

• Molecules and Cells
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• v.41 no.6
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• pp.582-590
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• 2018

Endothelial progenitor cells (EPCs) and outgrowth endothelial cells (OECs) play a pivotal role in vascular regeneration in ischemic tissues; however, their therapeutic application in clinical settings is limited due to the low quality and quantity of patient-derived circulating EPCs. To solve this problem, we evaluated whether three priming small molecules (tauroursodeoxycholic acid, fucoidan, and oleuropein) could enhance the angiogenic potential of EPCs. Such enhancement would promote the cellular bioactivities and help to develop functionally improved EPC therapeutics for ischemic diseases by accelerating the priming effect of the defined physiological molecules. We found that preconditioning of each of the three small molecules significantly induced the differentiation potential of $CD34^+$ stem cells into EPC lineage cells. Notably, long-term priming of OECs with the three chemical cocktail (OEC-3C) increased the proliferation potential of EPCs via ERK activation. The migration, invasion, and tube-forming capacities were also significantly enhanced in OEC-3Cs compared with unprimed OECs. Further, the cell survival ratio was dramatically increased in OEC-3Cs against $H_2O_2$-induced oxidative stress via the augmented expression of Bcl-2, a pro-survival protein. In conclusion, we identified three small molecules for enhancing the bioactivities of ex vivo-expanded OECs for vascular repair. Long-term 3C priming might be a promising methodology for EPC-based therapy against ischemic diseases.

• Asian Spine Journal
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• v.12 no.6
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• pp.998-1009
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• 2018

Study Design: Olfactory ensheathing cells (OECs) from rat olfactory mucosa were cultured, characterized, and transplanted into a rat model of spinal cord injury (SCI). Purpose: To evaluate different doses of OECs in a rat model of SCI. Overview of Literature: SCI causes permanent functional deficit because the central nervous system lacks the ability to perform spontaneous repair. Cell therapy strategies are being explored globally. The clinical use of human embryonic stem cell is hampered by ethical controversies. Alternatively, OECs are a promising cell source for neurotransplantation. This study aimed to evaluate the efficacy of different doses of allogenic OEC transplantation in a rat model of SCI. Methods: OECs were cultured from the olfactory mucosa of Albino Wistar rats; these cells were characterized using immunohistochemistry and flow cytometry. Rats were divided into five groups (n=6 rats each). In each group, different dosage ($2{\times}10^5$, $5{\times}10^5$, $10{\times}10^5$, and >$10{\times}10^5$) of cultured cells were transplanted into experimentally injured spinal cords of rat models. However, in the SCI group, only DMEM (Dulbecco's modified Eagle's medium) was injected. Rats were followed up upto 8 weeks post-transplantation. The outcome of transplantation was assessed using the Basso, Beattie, Bresnahan (BBB) scale; motor-evoked potential studies; and histological examination. Results: Cultured cells expressed 41% of p75NTR, a marker for OEC, and 35% of anti-fibronectin, a marker for olfactory nerve fibroblast. These cells also expressed $S100{\beta}$ and glial fibrillary acid protein of approximately 75% and 83%, respectively. All the transplanted groups showed promising BBB scores for hind-limb motor recovery compared with the SCI group (p<0.05). A motor-evoked potential study showed increased amplitude in all the treated groups compared with the SCI. Green fluorescent protein-labeled cells survived in the injured cord, suggesting their role in the transplantation-mediated repair. Transplantation of $5{\times}10^5$ cells showed the best motor outcomes among all the doses. Conclusions: OECs demonstrated a therapeutic effect in rat models with the potential for future clinical applications.