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        검색결과 9,514

        6161.
        2006.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        해체비용 산정은 원자력시설에 대한 해체 설계 및 계획 수립하는 데 중요한 기술이다. 해체비용 산정은 해체활동 단계와 해체시설의 구성요소에 맞게 해체작업을 분류하여 계산을 해야 한다. 본 논문에서는 원자력연구시설 해체비용 산정 기술로 이용하기 위하여 해체비용항목 및 그룹의 구성요소와 해체대상물에 대한 작업시간 계산의 기준이 되는 단위비용 인자 구성요소를 도출함으로써 해체비용 산정에 필요한 기본 구조를 완성하였다. 또한 주요 해체활동 및 작업에 대한 비용 산정 시 구성요소에 대한 고려사항을 살펴보았다. 향후, 이러한 기법을 이용하여 원자력연구시설에 대한 해체비용 산정 및 평가 방법론을 확립하는데 기본 기술로 활용할 예정이다.
        4,000원
        6162.
        2006.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        PFC 제염기술은 원자력연구시설 핫셀 내부의 바닥이나 장치표면에 부착된 고방사능분진을 제거하기 위한 방법 중의 하나이다. 고가의 PFC 제염용액을 회수 정제후 재사용하고, 2차폐기물발생을 획기적으로 줄일 수 있는 여과장치를 개발하였다. PFC 매질 내 현탁성 방사성입자를 제거하기 위해 오염특성에 적합한 여과장치를 개발하고 입자제거 성능평가시험을 수행하였다. 개발된 PFC 여과장치는 핫셀 내부로 들어갈 수 있게 알맞은 크기와 무게로 제작되었으며 바퀴와 고리를 부착하여 이동이 용이하다. PFC 여과장치의 성능평가결과 모의입자의 농도 증가 시 flux가 감소하였고, Pre-filter()와 final-filter() 두개를 장착하여 여과시간에 따른 flux의 감소를 개선하였다. 개발된 PFC 여과장치는 분당 약 0.2L의 PFC 폐액을 처리 할 수 있다.
        4,000원
        6163.
        2006.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        우라늄 변환시설 가동 중 발생하여 라군(lagoon)에 저장중인 방사성 슬러지 폐기물에 대한 처리는 시설 해체과정에서 매우 중요한 업무 중 하나이다. 슬러지 구성성분 중 다량을 차지하는 질산암모늄의 폭발 위험성 등으로 인해 미생물을 이용한 질산염의 분해는 질산염을 안정적으로 처리할 수 있는 효과적인 방법이라 할 수 있다. 본 연구에서는 라군 슬러지의 약 60 wt%를 차지하는 질산염을 혐기성 균주의 하나인 Pseudomonas halodenidificans를 이용하여 탈질하기위한 공정 변수에 대한 영향을 평가하였다. 온도, 질산염 농도, 전자공여체의 영향, C/N 비율, 초기 접종하는 균주의 비율, pH등의 공정변수에 대하여 실험한 이번 결과는 향후 연속식 공정 설계를 위한 기초 자료로 사용될 것이다.
        4,000원
        6164.
        2006.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        최근 미국 ANL연구소가 개발한 다이포실 수지는 우라늄의 선택특성이 우수하나 수지의 형태가 분말형이므로 입상의 비드형으로 제조하기 위하여 다이포실 분말을 알기네이트상에 고정화하는 방법을 적용하였다. 생성된 비드의 우라늄에 대한 흡착특성을 측정한 결과, 소디움 알기네이트 자체도 우라늄 흡착특성을 최대 68%까지 나타낸 후 30% 수준으로 감소하였으며, 이는 흡착후 탈착하는 과정을 거쳐 평형에 이르는 것으로 사료된다. 또한 비드내 다이포실의 양이 증가할수록 우라늄의 흡착이 증가하며 최대 85 %정도의 흡착율을 나타내고 있다. 다이포실 수지만의 경우 반응초기에 급격한 흡착을 보이고 있으나 3일정도 이후에는 비드의 흡착율과 유사한 결과를 나타내고 있으며 비드내 함유된 순 다이포실량을 고려할 경우 알기네이트 자체의 흡착효과로 인해 비드의 흡착효율이 크게 상승되는 것으로 해석된다. 우라늄 농도의 영향은 농도의 증가에 따라 우라늄의 제거효율이 감소하였으며, 비드의 양을 2배로 증가시킨 결과 최대 90%이상의 제거효율을 얻었다. 결론적으로 다이포실 수지를 소디움 알기네이트상에 고정화하여 입자형의 비드로 제조하므로서 적은 양의 수지로 우라늄 제거특성이 우수한 비드를 얻을 수 있었으며 나아가서 연속공정에의 적용도 가능한 것으로 사료된다.
        4,000원
        6165.
        2006.06 구독 인증기관 무료, 개인회원 유료
        This study was conducted to detect the apoptosis incidence in blastocysts and to compare the abundance of Bax, Bcl2L1, VEGF and FGFR2 in in vitro fertilized (IVF), parthenogenetic (PAT) and nuclear transfer (NT) embryos. Oocytes matured for 40 hr were enucleated and reconstructed with confluenced fetal fibroblasts (FFs) derived from a ~45 day fetus. Reconstructed eggs were then fused with 2 DC pulses (2.0 kV/cm, 30 μsec) and cultured with 7.5 μg/ml cytochalasin B for 3 hr. Parthenotes (PAT) were produced with the same electric strength and culture for NT eggs. The embryos were cultured in NCSU-23 medium at 39℃, 5% CO2, 5% O2 in air. In 3 runs, set of 10 embryos at the 4-cell to blastocyst stages were used to extract total RNA for analyzing the gene expression patterns of pro-apoptotic (Bax), anti-apoptotic (Bcl2L1), vasculogenesis (VEGF), implantation (FGFR2III) using real-time quantitative PCR. Cleavage and blastocyst rates were significantly higher (P<0.05) in IVF and PAT (79.3±8.5 and 25.5±6.1, and 85.0±6.4 and 38.6±5.5, respectively) than NT counterparts (65.1±5.2 and 15.6±3.0, respectively). Significantly higher (P<0.05) total cells were observed in IVF controls and PAT (34.7±5.8 and 38.1±4.1) than NT embryos (24.8±3.2). Apoptosis index was significantly lower (P<0.05) in IVF than NT embryos. The Relative abundances (RA) of Bax and VEGF were significantly higher (P<0.05) at blastocyst stage in NT than IVF control. The RA of Bcl2L1 and FGFR2III were significantly higher (P<0.05) at blastocyst stage in IVF than NT. The present study observed the abnormal gene expressions in NT embryos at various developmental stages, suggesting certain clues to find out the cause of the low efficiency of NT to term.
        4,000원
        6167.
        2006.06 구독 인증기관 무료, 개인회원 유료
        Cyclin B1 is known to reflect the M-phase promoting factor (MPF), a universal regulator of G2/M-phase transition, activity during the process of oocytes maturation. To investigate whether culture condition affects the maturation rate and the expression of cyclin B1 protein, bovine immature oocytes are stimulated and cultured according to the following protocols: Experiment 1: denuded oocytes (denude) only, COC only, denuded oocytes + granulosa cells (denude + GCs) and COC + GCs; Experiment 2: no-activation (control), 7% ethanol for 5 min and 10 l/ml ionomycin for 5 min at immediately before maturation. The maturation rates of denude and no-activation group were significantly lower in both experiments (P<0.05), respectively. Co-culture or stimulation method in bovine immature oocytes culture increases the cyclin B1 expression significantly in both experiments (P<0.05). Based on these results, culture condition affects the maturation rate and the expression of cyclin B1 protein during the first meiotic maturation in bovine immature oocytes.
        3,000원
        6168.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문의 연구목적은 Choroidal neovascularization (맥락막 신생혈관) 모텔에서 HO-1 발현제와 억제재의 영향을 알아보고자 한다. 30마리의 Brown Norway rat을 각각 10마리씩 세 그룹, Hemin treated group, SnPP treated group, Contorl group으 로 나누어서 실험을 진행하였다. Hemin treat group은 10μmol/kg hemin(Frontier Scientific Inc. USA) 을 SnPP treat group은 10 μmol/kg SnPP(Frontier Scientific Inc. USA)을 laser 시술 2 일에서 14 일까지 복강내 주사하였고 Control군은 0.5 mß씩 식 염 수를 주사하였다. 14 일 후 안저사진촬영과 형광안저촬영을 실시하였다. SnPP treated group에서 Hemin treated group보다 더 많은 선생혈관이 생성되었다. Hemin treated group에서는 맥락막 신생혈관 형성의 정도가 정상대조군에 비교하여 저하됨을 알 수 있었다. 본 연구의 결과 HO-1 의 inducer 인 Hemin 이 맥락막의 신생혈관 억제에 영향을 미치는 것으로 보여진다.
        4,000원
        6169.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The electro-chemical removal (ECR) of water pollutants by metal-ACF electrodes from wastewater was investigated over wide range of ECR time. The ECR capacities of metallic ACF electrodes were related to physical properties such as adsorption isotherm, surface area and pore size and to reaction time. Surface morphologies and elemental analysis for the metal supported ACFs after electro-catalytic reaction were investigated by scanning electron microscopy (SEM) and energy disperse X-ray (EDX) to explain the changes in adsorption properties. The IR spectra of metallic ACFs for the investigation of functional groups show that the electro-catalytic treatment is consequently associated with the removal of pollutants with the increasing surface reactivity of the activated carbon fibers. The metal-ACFs were electro-catalytically reacted to waste water to investigate the removal efficiency for the COD, T-N, NH4-N, NO3-N and NO2-N. From these removal results of the piggery waste using metallic ACFs substrate, satisfactory removal performance was achieved. The removal efficiency of the metallic ACFs substrate was mainly determined by the properties of the material for adsorption and trapping of organics, and catalytic effects.
        4,000원
        6170.
        2006.06 구독 인증기관 무료, 개인회원 유료
        The growing oocytes become progressively capable of resuming meiosis, and full meiotic competence appear when they are about 80% of the size of fully grown oocytes. As hormonal influences vary at different stages of reproductive cycle, the size of oocytes may vary according to the reproductive stages. The present study was designed to compare the diameter between the ovulated and freshly collected immature canine oocytes. The ovulated oocytes were collected 72 hr after ovulation by oviductal tube flushing by laparotomy under general anesthesia. Immature oocytes were collected by ovarian slicing method. Diameter of all oocytes was measured directly using epiflurescence microscope with a calibrated micro-eyepiece micrometer at ×200 magnification. The thickness of zona pellucida and diameter of cytoplasm were measured separately and recorded. A total of 2209 zona intact oocytes were collected, among them 628 from anestrus, 675 from follicular, 838 from luteal and 68 by fallopian tubes flushing methods. The average number of oocytes was 104.7, 168.8, 119.7 and 11.3 for anestrus, follicular, luteal and fallopian tubes flushing methods, respectively. The average diameters of the ooplasm and oocyte were significantly varied in different reproductive stages as well as with ovulated oocytes (P<0.05). The average diameter of ooplasm and oocyte was 115.6 and 127.7, 143.0 and 162.0, 134.6 and 150.6, 159.6 and 185.6 for anestrus, follicular, luteal and ovulated oocytes, respectively. Highest number of oocytes with larger diameter could be collected from the follicular and luteal stages. In conclusion, the follicular and luteal ovaries are the best sources of oocytes for canine IVM.
        4,000원
        6171.
        2006.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        알파분광법에 의한 의 정량방법을 검토하였다. 황산염 매질에서 전류세기, 전착시간 및 유기물 첨가제 둥의 변화에 따른 의 전착조건을 찾은 결과 A에서 유기첨가제 없이 시간 동안 전착하는 것이 효율적이었다. 을 4.16 Bq에서 0.0264 Bq(1ng) 까지 전착한 결과 농도가 낮을수록 전착율 및 재현성이 낮아졌으며 1 ng 까지 측정이 가능하였다. 사용후 핵연료 합성용액에서 을 분리한 후 알파분광법으로 측정하여 정량한 결과 (n=4)의 회수율을 나타내었다. 사용후 핵연료 시료용액 중 을 정량하였으며 계산 값과 비교한 결과 10% 이내에서 서로 일치하였다.
        4,000원
        6172.
        2006.06 구독 인증기관 무료, 개인회원 유료
        The possibility of producing transgenic embryos expressing the green fluorescence protein (GFP) gene have been evaluated after transfer of exogenous gene into the porcine zygote cytoplasm using the intracytoplasm sperm injection (ICSI) as gene delivery method. For DNA binding to sperm heads, 0.05% Triton X-100 or Lipofectin was used. After injection of the sperm bound to DNA by means of Lipofectin or Triton X-100 triturate, the blastocyst formation rates on day 6 were not significantly different from that of ICSI only group (18.8, 19.2 and 25.3%). In terms of GFP expression, more embryos were in GFP form in Triton X-100 group than in Lipofectin group (40.6 vs 36.4%), while percentage of non-mosaic embryos expressing the GFP gene in all blastomere was higher (P<0.05) in Lipofectin group than in Triton X-100 group (4.2 vs 0.9%). ICSI embryos derived from sperm treated with Lipofectin/DNA complex was transferred into 3 recipients and were collected by uterine flushing on days 5, 7 and 15 after embryo transfer, and then GFP expression was observed by a fluorescence microscopy. Over 26% of the collected embryos were normally expressed GFP gene. These results suggest that foreign gene transfer method with DNA bound sperm caused minimal damage to structure of oocytes that can result to full development of porcine embryos. This was confirmed in this study when the embryos that were transferred after ISCI of DNA bound sperm had a normal development and gene expression until preimplantation.
        4,000원
        6173.
        2006.06 구독 인증기관 무료, 개인회원 유료
        This study was conducted to examine the effect of IRES controlled reporter gene on screening and production of recombinant human erythropoietin (EPO) proteins from cultured CHO cells. The cDNA was cloned for EPO from human liver cDNA. Using site-directed mutagenesis, we generated recombinant human EPO (rhEPO) with two additional N-glycosylations (Novel erythropoiesis-stimulating protein: NESP). Wild type hEPO and NESP were cloned into expression vectors with GFP reporter gene under regulatory control of CMV promoter and IRES so that the vectors could express both rhEPO and GFP. The expression vectors were transfected to cultured CHO-K1 cells. Under microscopy, expression of GFP was visible. Using supernatant of the culture, ELISA assay, immunocytochemistry and in vitro assay using EPO dependant cell line were performed to estimate biological activity to compare the production characteristics (secretion levels, etc.) between rhEPO and NESP. The activity of NESP protein, obtained by mutagenesis, was described and compared with its rhEPO counterpart produced under same conditions. Although NESP had less secretion level in CHO cell line, the biological activity of NESP was greater than that of rhEPO. These results are consistent with previous researches. We also demonstrated that rhEPO and GFP proteins expressed simultaneously from transfected CHO cell line. Therefore we conclude that use of GFP reporter gene under IRES control could be used to screen and produce rhEPO in cultured CHO cells.
        4,000원
        6174.
        2006.06 KCI 등재 구독 인증기관·개인회원 무료
        Agaricus blazeiMurill is an edible mushroom distributed in Brazil and presently cultivated in other areas, including Korea, Japan, and China. Its chemical components, including steroids and lectin and various polysaccharides have been widely studied. For this, we used U937/vector and U937/Bcl-2 cells, which were generated by transfection of the cDNA of the Bcl-2 gene. As compared with U937/vector, U937/Bcl-2 cells exhibited a 4-fold greater expression of Bcl-2. Treatment with 0.5 or 4 mg/ml A. blazei Murill for 24 h produced morphological features of apoptosis in U937/vector cells, respectively. This was associated with caspase-3 activation and PARP degradation. In contrast, A. blazei Murill-induced caspase-3 activation and PARP degradation and apoptosis were significantly inhibited by z-DEVD-fmk in U937 cells. Bcl-2 overexpressing cells exhibited sustained caspase-3 activation and expression levels of the Bcl-2 proteins during A. blazei Murill-induced apoptosis. In addition, these findings indicate that Bcl-2 inhibits A. blazei Murill-induced apoptosis by a mechanism that interferes with Bcl-2 degradation and activity of caspase-3 that is involved in the execution of apoptosi.
        6176.
        2006.06 구독 인증기관 무료, 개인회원 유료
        R-type(Cav2.3) calcium channel contributes to pain sensation in peripheral sensory neurons. Six isoforms of Cav2.3 that result from combinations of presence or deletion of three inserts(insert I and insert in the II-III loop, and insert III in N-terminal regions) have been demonstrated to be present in different mammalian tissues. However, the molecular basis of Cav2.3 in trigeminal ganglion(TG) neurons is not known. In the present study, we determined which isoforms of Cav2.3 are expressed in rat TG neurons using the RT-PCR analysis. Whole tissue RT-PCR analyses revealed that only two isoforms, Cav2.3a and Cav2.3e, were present in TG neurons. From single-cell RT-PCR, we found that Cav2.3e rather than Cav2.3a was the major isoform expressed in TG neurons, and Cav2.3e was preferentially detected in small-sized neurons that express nociceptive marker, transient receptor potential vanilloid 1(TRPV1). Our results suggest that Cav2.3e in trigeminal neurons may be a potential target for the pain treatment.
        4,000원
        6178.
        2006.06 구독 인증기관 무료, 개인회원 유료
        Malaysian secondary school teachers' readiness to use Information Communication Technology (ICT) is considered a critical skill in terms of national goals for schools that will prepare students to compete in the knowledge economy of the 21st century. The study investigated 303 teachers' ICT readiness in terms of their basic ICT knowledge, skills, and attitudes towards ICT. Data were collected via the Teachers' ICT Readiness instrument which consisted of an ICT knowledge test, an ICT skills test, and attitude towards ICT questionnaire. The results indicated that the majority of teachers had a moderate level of basic ICT knowledge and skills. A majority of the teachers too had a positive attitude towards ICT. Discussion and recommendations focus on the need to capitalize on the positive attitudes to turn these into action, increasing readiness to use ICT.
        4,000원