• Korean Journal of Animal Reproduction
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• v.20 no.3
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• pp.279-288
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• 1996

The objective of this study was to determine the effect of EGF on the development of IVM/IVF bovine embryos and their ICM and TE cell number. In addition, we examined the combined effect of EGF and coculture to the bovine embryo development and the expression of EGF-R protein on bovine embryos by indirect immunofluorescence. The results obtained in these experiments were summarized as follows: When the IVM/IVF 4- to 8-cell embryos were treated at 0, 1, 10, 100 ng/ml of EGF, EGF treatment group showed improved development to blastocyst and increased pattern of ICM and TE cell number compared with control, although there is not significantly different. The stimulating effect of EGF (10 ng/ml) to the develop ment level of IVM/IVF bovine embryos significantly increased development rate to blastocyst after 8-cell stage (p<0.05), although there is no significant effect to the increase of ICM and TE cell numbers. Also, expression of EGF-R on the bovine embryonic stage by indirect immunofluor escence presents after 4-cell stage and the intensity of the EGF-R staining was variable with the development progression. On the other hand, embryos cultured in coculture group added either with or without EGF commonly indicated the significant difference in development rate to blastocyst and Total cell number compared with control. These results suggest that the a addition of EGF to the coculture may stimulate the coculture effect between IVM/IVF bovineembryos and cumulus cells. Therefore, EGF could promote preimplantation bovine embryo development by binding with expressed EGF~R after 4-cell stage, and stimulate the production of embryotrophic factors from the coculture environment. Also, the present study showed that there was no significant effect of EGF to the increase of ICM and TE cell number although the rate of blastocyst significantly increased when treated with EGF after 8-cell stage (p<0.05).

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.91-101
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• 2000

The emission sources of volatile organic compounds (VOCs) are wastewater treatment plants. sanitary landfills, automobile industries, and so on. The VOCs are harmful to human beings because of their toxicity and carcinogenicity, and cause the serious air pollution problem producing ozone ($O_3$) as a result of photochemical reaction. To investigate the emission of VOCs from wastewater treatment plant, aeration basins at the City of Los Angeles' Hyperion Treatment Plant were selected and measured flux was compared with calculated flux. For compounds commonly associated with wastewater (DCM, TCM, PCE, UM, DCB, UND) and not expected in vehicle exhaust or ambient air coming off the ocean, concentrations immediately downwind of the aeration basins were a factor of ten or higher than those measured in the upwind air. The airborne flux of less degradable or non-biodegradable compounds, e.g., DCE, DCM, TCA, DCA, TCM, PCE, DCB, through an imaginary plane at the downwind side of the aeration basins was in agreement with the estimated flux from measured liquid phase concentrations. Henry's constant. aeration rate, and an assumption of bubble saturation. For several compounds (PCE, DCE, TCA), the ratio (measured flux/calculated flux) is almost unity.

• Membrane Journal
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• v.14 no.4
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• pp.289-297
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• 2004

In this study, membranes were coupled to a sequencing batch reactor for simultaneous removal of organic matter and nitrogen, and the influences of MLSS (mixed liquor suspended solid) concentration and the sludge loading rate on membrane fouling and bioactivity were investigated. The amount of membrane fouling slightly increased with MLSS concentration at both non-aeration and aeration conditions, but effect of MLSS concentration was more significant at aeration condition. Although the effect of MLSS concentration on membrane fouling was found to be insignificant at low concentration level, extremely low sludge loading, which were generated by the maintenance of large amount of biomass in the reactor, caused severe membrane fouling, and air scouring effect decreased significantly in this condition. Specific bioactivity was constantly reduced as sludge loading rate decreased. In spite of high MLSS concentration over 17,000 mg/L, the activity of the reactor decreased at extremely low sludge loading rate presumably due to the lower oxygen transfer and the competition of biomass to deficient substrate.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.6
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• pp.428-433
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• 2009

Dissolved oxygen is considered as one of the important water-quality constituents in streams from one century ago and fishes perish in low dissolved oxygen concentration. Environmental scientists and engineers have introduced the deterministic model to estimate dissolved oxygen concentration of streams and recommended the use of the Delta Method (DM), Approximate Delta Method (ADM), Extreme Value Method (EVM) and Optimization Method (OPT) which can be applied in no spatial variation of dissolved oxygen. The diurnal or annual variation of dissolved oxygen is mainly determined from the parameters such as reaeration rate, 1st production rate and respiration rate which are related to dissolved oxygen. Each method was briefly introduced and applied to two sampling sites of Anseong Stream watershed in this paper. The limitation, advantages and disadvantages of each method were reviewed and analyzed after running the each method. From these analyses, the benefit-cost approach to estimate dissolved oxygen effectively in streams was recommended.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.1
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• pp.1-8
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• 2002

Chufa (Cyperus esculentus L.) belongs to one of the sedge family and pows well in summer. The aboveground part of chufa is mostly consisted of leaves and the underground part is mostly composed of a clump of fibrous root with tuber. At the seeding year, it does not reproductive development but produces a lot of tuber. It produced many tillers from the tuber and grows in clumps as a bunch type. The plant height of mature chufa was 73 to 75cm and it grown fully in the middle of July. The number of tillers were increased rapidly until the end of July and still increased slowly after August but it showed very poor growth. The final fresh weight and dry matter yield of aboveground part of chufa were 40.3 tou/ha and 12.1 tou/ha. respectively. The regrowth of aboveground part was vigorous in the early stage of growth after 1st cutting but it was decreased rapidly after the second cutting. In control plot, the number of tubers per a clump were 722 at final stage and their fresh and drymatter yields per m: were 4.2kg and 1.9kg, respectively. In experimental plots, the amount of tubers was decreased steadily according to delay of cutting date, but late cutting date was not affect the tuber formation severely because the tuber produced already early in August. The nutritive value of chufa in vegetative growth stage was good but it was decreased according to growing up. The contents of crude protein(CP), neutral detergent fiber(NDF), dry matter digestibility (DMD) and total digestible nutrients(TDN) of aboveground part of chufa harvested finally were 6.1%, 51.5%, 39.8%, 33.2% and 39.4％, respectively. The contents of crude protein(CP), neutral detergent fiber(NDF), dry matter digestibility(DMD) and total digestible nutrients(TDN) of tubers of chufa were 6.1%, 81.5%, 39.8%, 33.2% and 39.4%, respectively and the content of oil was as high as 16.2%, especially.

• Journal of Chest Surgery
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• v.30 no.2
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• pp.125-130
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• 1997

Separating the patient from hypothermic cardiopulmonary bypass(CPB) before achieving adequate rewarming often results in afterdrop, which can predispose to electrolyte disturbances, arrhythmia, hemodynamic alterations, and shivering-induced increase of oxygen consumption. In an attempt to find an adequate end point temperature of rewarming after hypothermic CPB, 50 pediatric cardiac surgical patients were r ndomly assigned for end point temperature of rewarming of 35.5$^{\circ}C$ (Group 1) or 37t (Group 2), rectal temperature. Thereafter the rectal temperature was measured half, one, four, eight, and 16 hour after arrival to the intensive care unit(ICU), with heart rate and blood pressure. Additionally the rectal temperature was compared with esophageal temperature during CPB, and axillary temperature luring stay in the ICU. Nonpulsatile perfusion with a roller pump was used in all patients and a membrane or bubble oxygenator was used for oxygenation. Both groups were comparable with respect to age, sex, body surface area, total bypass time, and rewarming time. There was no afterdrop in both groups, and there were no statistical differences in the rectal temperatures between two groups. There were also no statistical dilyerences with respect to the heart rate and blood pressure between two groups. At the end of rewarming the esophageal temperature was higher than the rectal temperature. The axil ary temperature measured in ICU was always lower than the rectal temperature. No shivering was noted in all patients. In conclusion, with restoration of rectal temperature above 35.5$^{\circ}C$ at the end of CPB in pediatric patients, we did not observe an afterdrop.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.27-52
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• 2003

지금 우리 농업과 농촌은 대내외적으로 시련기를 맞고 있다. 농가소득의 상대적인 하락(도시근로자의 4분의 3 수준), 농촌 지역의 보건ㆍ의료 기반과 문화시설의 취약, 교육 여건의 미흡 등으로 농업을 포기하고 이농을 하는 젊은 농업 인이 늘어나고 있는 실정이다. 이러한 가운데 도하개발의제(DDA) 농산물협상, 자유무역협정(FTA) 체결 등 농산물 시장개방은 피할 수 없는 압력이 되고 있다. 더욱이, 농가의 농업소폭의 전반, 농가소득의 1/4를 차지하는 쌀 농업은 과잉재고, 소비 감소, 개방 압력 등으로 큰 시련을 겪고 있다. 정부 수매, 쌀값지지 등 정부의 보호정책은 후퇴 내지는 폐지될 수밖에 없는 환경에 놓여 있다. (중략)

• The Optical Journal
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• s.97
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• pp.18-23
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• 2005

젊은층을 중심으로 폰카메라와 더불어 패션 아이콘으로 자리잡은 디지털카메라의 고속성장은 계속되고 있는 가운데 올해는 3~4년전 200만 화소대 이하 제품을 구매했던 소비자들의 교체수요와 맞물려 그 어느때보다 카메라 메이커간 시장 1위 다툼이 치열할 것으로 보인다. 특히 세계적으로 디카 시장이 어느정도 성숙기에 접어들면서 가격경쟁이 심화됨에 따라 결과적으로 메이커들의 수익성 문제로 불거졌고 카메라 사업을 포기하거나 사업구조를 개편하면서 수익성을 확보하려는 메이커들도 생겨나는등 시장 재편의 조짐도 보이고 있다. 이는 국내 시장에도 영향을 미쳐 올해는 그 어느때보다 메이커간 치열한 공방전과 국내 시장의 지각변동이 예상되고 있다.

• The Optical Journal
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• s.96
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• pp.14-16
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• 2005

국내 광산업은 IMF를 거치면서 많은 대기업들이 사업을 포기함으로써 중소기업 위주로 개편되었다. 전체적인 시설투자는 일시적으로 줄었지만 기술력 중심의 전문기업들이 많이 생겼고, 다행스럽게도 삼성전자 등에서 지속적으로 관련 산업을 유지함으로써 새로운 도약기를 맞이하고 있다. 국책연구소들도 특성화된 분야에서 세계적인 연구성과를 발표하고 있으며, 대학에서는 광공학 관련 학과들이 많이 생겨서 전문인력을 양성하고 있다. 개발경쟁이 심한 광산업에서 다양한 첨단 광학계를 개발하기 위한 전반적인 기술 인프라가 아직은 부족하지만 산학연이 지금과 같이 계속 노력한다면 앞으로 광산업 선진국에 충분히도약할 것으로 확신한다.

• Journal of Embryo Transfer
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• v.18 no.1
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• pp.15-25
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• 2003

발생학에서 키메라(chimera)는 2개 이상의 다른 유전자형의 세포, 또는 다른 종의 세포로부터 만들어진 1개의 생물개체를 뜻하는 말로, 이는 초기 수정란의 발달과 포유류의 분화를 연구하는데 이용되고 있다. 키메라를 만드는 방법에는 할구와 내세포괴를 응집시키는 방법과 배반포 내에 여러 종류의 세포를 주입하는 방법이 있다 본 실험에서는 서로 다른 두 가지 방법의 활성화 처리법, 즉, ionomycin 처리 후 Cycloheximide (CHX) 또는 6-Dimetylaminopurine (6-DMAP)에 따른 단위 발생란의 분할과 단계적인 발달율을 살펴 보고자 하였으며, 서로 다른 방법에 의해 생산된 단위발생란 유래의 할구와 체외수정란 유래 할구를 응집하여 키메라 수정란(chimeric embryo)를 만든 후 체외수정란과 발달율을 비교해 보았다. 도축장 유래의 난소에서 난자를 채취하여 체외에서 22~24시간 성숙시킨 후 난구세포를 제거하고 metaphase II 단계의 난자를 5 $\mu$M ionomycin에 4분간 처리한 후, 10 $\mu$g/ml CHX/5 $\mu$g/ml cytochalasin B (CCB)에 5시간 또는 1.9 mM 6-DMAP에 4시간 처리하여 분할율과 배반포기 발달율을 비교 조사하였다. 난자 분할율에서는 체외수정란과 6-DMAP처리 단위 발생란에서 각각가 83.7 와 85.5%로 CHX/CCB 처리 단위발생란의 57.9%보다 유의적으로 높게(P<0.05) 나타났으며, 배반포기 발달율에 있어서는 체외수정란의 발달율이 27.8%로 6-DMAP처리 활성란 12.3%와 CHX/CCB 처리 활성란 5.3%보다 유의적으로 높게 (P<0.05) 나타났다. 키메라 수정란(chimeric embryo)은 서로 다른 두 가지 처리에 의해 생산된 단위발생란의 할구 2개와 체외수정란 유래의 할구 2개를 빈 투명대 내에서 응집시켜 제조하였다 빈 투명대 내에 키메라 수정란(chimeric embryos)의 8 세포기까지의 발달율은, 체외 수정란 할구 2개와 CHX/CCB 처리에 의한 할구 2개를 응집한 그룹은 46.1%, 체외 수정란 할구와 6-DMAP 유래 할구 2개를 응집한 그룹은 52.8% 였으며, handled control은 54.7%로 체외 수정란 77.7%에 비해 유의적으로 낮게(P<0.05) 나타났다. 배반포기까지의 발달율은 체외 수정란과 CHX/CCB에 의해 생산된 키메라 수정란(chimeric embryo)은 12.8%, 체외 수정란과 6-DMAP에 의한 키메라 수정란(chimeric embryo)은 18.8%로 handled control의 21.4%에 비해 유의적으로 낮았으며(P<0.05), 이들 키메라 수정란(chimeric embryos)은 체외 수정란의 34.9%에 비해 유의적으로 낮게(P<0.05)나타났다. 6-DMAP 처리 단위발생이 유기된 수정란 할구 2개와 체외수정란의 할구 2개의 응집에 의한 키메라 수정란(chimeric embryos)의 발달율이 CHX/CCB와 체외수정란의 응집에 의한 키메라 수정란(chimeric embryos)에 비해 다소 높게 나타났으나, 유의적인 차이는 없었다. 본 실험의 결과 서로 다른 방법에 의한 단위 발생란 유래의 할구와 체외 수정란 유래의 할구가 응집에 의한 재조합이 가능하였고 이들을 체외에서 배양하여 배반포기의 수정란까지 발달시켰다.