• 정보교육학회논문지
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• 제18권2호
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• pp.235-242
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• 2014

국내외의 여러 기관과 단체에서는 21세기 학습자가 갖추어야 할 핵심 역량의 하나로 ICT 능력을 선정하고 있다. 따라서 한국정보교육학회에서는 정보 교과의 내용 체계에 대한 개정안에 대하여 연구하였으며, 정보 교육 내용을 '컴퓨터 시스템', '소프트웨어 제작' 및 '융합 활동'의 세 영역으로 구분하는 내용세계를 제시하였다. 이에 따라 본 논문에서는 한국정보교육학회에서 제시한 정보교과 내용체계의 '융합활동' 영역 중 생산성 도구에 대한 초등학교 및 중학교의 성취 기준을 학년군별로 마련하였다. 그 결과, 초등학교 1-2학년군에서는 그리기 도구를, 3-4학년은 문서 작성 도구를, 5-6학년은 멀티미디어 도구를, 중학교 1-3학년군은 자료분석 도구를 각각 선정하였다. 그리고 이 성취 기준을 도달하기 위한 교수 학습 방법과 평가 방안을 학년군 별로 세분화하여 제시하였다. 이와 같이 본 연구에서 제시한 '생산성 도구'에 대한 성취기준, 교수 학습 방법, 평가 방법은 향후 초 중등학교 정보교과 교육과정을 개발하는데 기여할 것으로 기대된다.

• BMB Reports
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• 제40권6호
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• pp.911-920
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• 2007

Tuberculosis, caused by Mycobacterium tuberculosis, continues to be one of the leading infectious diseases to humans. It is urgent to discover novel drug targets for the development of antitubercular agents. The 2-C-methyl-Derythritol-4-phosphate (MEP) pathway for isoprenoid biosynthesis has been considered as an attractive target for the discovery of novel antibiotics for its essentiality in bacteria and absence in mammals. MEP cytidyltransferase (IspD), the third-step enzyme of the pathway, catalyzes MEP and CTP to form 4-diphosphocytidyl-2-C-methylerythritol (CDP-ME) and PPi. In the work, ispD gene from M. tuberculosis H37Rv (MtIspD) was cloned and expressed. With N-terminal fusion of a histidine-tagged sequence, MtIspD could be purified to homogeneity by one-step nickel affinity chromatography. MtIspD exists as a homodimer with an apparent molecular mass of 52 kDa. Enzyme property analysis revealed that MtIspD has high specificity for pyrimidine bases and narrow divalent cation requirements, with maximal activity found in the presence of CTP and $Mg^{2+}$. The turnover number of MtIspD is $3.4 s^{-1}$. The Km for MEP and CTP are 43 and $92{\mu}M$, respectively. Furthermore, MtIspD shows thermal instable above $50^{\circ}C$. Circular dichroism spectra revealed that the alteration of tertiary conformation is closely related with sharp loss of enzyme activity at higher temperature. This study is expected to help better understand the features of IspD and provide useful information for the development of novel antibiotics to treat M. tuberculosis.

• 한국안광학회지
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• 제19권1호
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• pp.121-133
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• 2014

목적: 본 연구는 최근 5년간 연령에 따른 근시 유병률 진행을 비교 분석하였다. 방법: 보건복지부 산하 질병관리 본부에서 시행한 2008에서 2012년까지의 국민건강영양조사 자료를 통해 근시 유병률 진행을 비교 분석하였다. 결과: 최근 5년간 자료를 통해 근시를 분류하였고, 연령별 분석결과 약도근시 중 5-11세는 25.5%, 12-18세는 25.1%, 19-29세는 27.3%, 30-39세는 30.7%, 40-49세는 29.6%, 50-59세는 19.2%, 60-69세는 11.8%, 그리고 70세 이상에서는 20.2%의 근시유병률이 각각 나타났다. 중도근시 중 5-11세는 21.7%, 12-18세는 43.6%, 19-29세는 36.2%, 30-39세는 30.0%, 40-49세는 20.4%, 50-59세는 9.9%, 60-69세는 5.2%, 그리고 70세 이상에서는 7.6%의 근시 유병률이 각각 나타났다. 고도근시 중 5-11세는 2.1%, 12-18세는 11.7%, 19-29세는 11.5%, 30-39세는 6.9%, 40-49세는 5.6%, 50-59세는 1.9%, 60-69세는 1.5%, 그리고 70세 이상에서는 1.0%의 근시 유병률이 각각 나타났다. 결론: 근시 유병률 진행 증가에 대한 중요성을 인식하여 국민의 안보건복지와 시력저하 방지를 위한 제도적 장치와 사회적 관심이 더욱 필요할 것을 판단된다.

• 한국수정란이식학회지
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• 제10권1호
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• pp.65-72
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• 1995

The purposes of this study were to produce cloned rabbit embryos and offsprings by nuclear transplantation(NT) using in vitro matured oocytes as nuclear recipient cytoplasm and to determine the effect of frozen nuclei donor embryos on the production efficiency of cloned embryos. The 8cell embryos were collected from the mated does by flushing oviducts with Dulbecco's phosphate buffered saline containing 10% fetal calf serum(FCS) at 40 hours after hGG injection. A portion of collected embryos were preserved at 4$^{\circ}C$ for 24 hours and a portion of them were frozen by vitrification method. The embryos used for donor nuclei were synchronized in the phase of Gi /S transition. The in vitro matured oocytes were used as recipient cytoplasm following removing the nucleus and the first polar body. The synchronized blastomeres from fresh, cooled or frozen embryos were injected into the enucleated oocytes by micromanipulation and were electrofused by electrical stimulation of three pulses for 60 $\mu$sec at 1.0 W /cm in 0.28 M mannitol solution. The fused oocytes were co-cultured with a monolayer of rabbit oviductal epithelial cells in M-199 solution containing 10% FCS for 120 hours at 39$^{\circ}C$ in a 5% $CO_2$incubator. Following in vitro culture of the NT embryos to blastocyst stage, they were stained with Hoechst 33342 dye for counting the number of blastomeres by fluorescence microscopy. The nuclear transplant embryos developed in vitro to 2- to 4-cell stage were transferred into the oviducts of synchronized recipient does. The results obtained were summarized as follows: 1. The fusion rates of the blastomeres from fresh, cooled and frozen embryos with the in vitro matured and enucleated oocytes were 100, 95.8 and 64, 3%, respectively. 2. Development in vitro to blastocyst was significantly(p<0.05) different between the cloned embryos with the blastomeres from fresh, cooled or frozen embryos as 39.0, 20. 9 and 15.7%, respectively. 3. The mean numbers of cell cycle per day during in vitro culture of cloned embryos blastomeres from fresh, cooled or frozen embryos was 1.31, 1.29 and 1.16, respectively. 4. A total of 77 nuclear transplant embryos were transferred into 6 recipient does, of which two offsprings were produced from a foster mother 31 days after embryo transfer.

• Journal of Plant Biotechnology
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• 제38권1호
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• pp.69-76
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• 2011

This study describes the effect of myo-inositol on sustained cell division and plant regeneration from cotyledon-derived protoplast of cabbage (Brassica oleracea var. capitata). Freshly isolated protoplasts were cultured in modified Murashige and Skoog (MS) medium removed ammonia ions and containing $0.4\;mg\;l^{-1}$ thiamine HCl, $100\;mg\;l^{-1}$ myo-inositol, $2\;mgl^{-1}$ 2,4-D, $0.5\;mgl^{-1}$ BA, $30\;gl^{-1}$ sucrose and several concentrations of myo-inositol (2, 4, 6, 8, 10% (w/v)) as an osmotic stabilizer. After 3 weeks of culture in the dark at $25^{\circ}C$, the plating efficiency of cabbage protoplasts reached to $22.5{\pm}2.9%$ when cultured in modified MS medium supplemented with $2\;mgl^{-1}$ 2,4-D, $0.5\;mgl^{-1}$ BA, $30\;gl^{-1}$ sucrose and 8% (w/v) of myo-inositol at a density of $2{\times}10^5$ protoplasts/ml. Rapidly growing cell colonies after 3 weeks of culture were transferred to the same culture medium removed osmoticum. To induce shoot regeneration from calluses, calluses with about 2 mm in diameter were transferred to the MS medium containing $2\;mgl^{-1}$ BA and $0.5\;mgl^{-1}$ NAA. After further three weeks of incubation onto the medium in the light, green shoots were formed on the surface of calluses at a frequency of 30%. Upon transfer to half-strength MS basal medium, roots were formed onto the bottom of regenerated shoots without auxin treatments. These regenerated plantlets were successfully acclimatized to soil transfer, grown to normal mature plants. The cabbage protoplast culture system established in this study could be applied for production of somatic hybrids or cybrids by asymmetric protoplast fusion and mass proliferation of elite somatic clones of cabbage.

• 설비공학논문집
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• 제23권4호
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• pp.243-250
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• 2011

In order to investigate the effects of PAG oil concentration on heat transfer performance and pressure drop during gas cooling process of $CO_2$, the experiments on fin-tube heat exchanger of $CO_2$ heat pump were performed. The experimental apparatus consists of a gas cooler, a heater, a chiller, a mass flow meter, a pump and measurement system. Experiments were conducted in various experimental conditions, which were inlet temperature($110^{\circ}C$), mass flow rates (50, 55, 60, 65, 70 g/s) and PAG oil concentration(0 to 2.6 wt%). Heat transfer rate decreased with the increase of the oil concentration and the decrease of inlet pressure. And pressure drop increased with the increase of the oil concentration and mass flow rate of refrigerant. The COP reduction by deterioration of gas cooler performance with oil concentration was analyzed. When inlet pressure of gas cooler is 100 bar, the COP reduction was estimated by 6% under 1 wt% of oil concentration.

• 농업과학연구
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• 제33권1호
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• pp.35-41
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• 2006

이종간의 핵이식은 확보가 쉬운 난자를 이용함으로서 용이한 수핵란의 확보와 윤리적인 문제등을 피할 수 있으므로 매우 유용한 방법이다. 본 연구에서는 이러한 이종간 핵이식의 조건을 규명하고자 유산양 태아섬유아세포를 이용하여 돼지의 난자에 이종간 핵이식을 시도하였다. 돼지와 산양의 난소에서 난포란을 채취하여 각각 NCSU-23, TCM-199에 호르몬을 첨가한 성숙배양액에 배양하여 $38^{\circ}C$, 5% $CO_2$의 배양기에서 48시간 동안 체외성숙 시켜 수핵난자를 준비하였다. 공여세포는 유산양의 태아섬유아세포는 DMEM배양액에서 배양한 후 0.25% Trypsin-EDTA 용액으로 처리하여 single-cell로 분리하여 사용하였다. 돼지와 산양의 성숙란에 공여세포를 핵치환하여 0.3 M mannitol fusion medium에 넣어 각각 DC 1.2 kV/cm $30{\mu}sec$과 DC 2.39 kV/cm $15{\mu}sec$의 조건으로 BTX를 이용 2회의 전기충격으로 융합 활성화하였다. 활성화된 돼지와 산양 핵이식란은 각각 PZM-3와 mSOF 배양액에 7일간 배양하면서 할구분열율과 배발달율을 관찰하여 동종간 핵이식란과 비교하였다. 비교결과 이종간 핵이식란의 경우 분열률이 58.9%, 배반포기로의 발달률이 5.4%로 돼지 동종간 핵이식란의 분열율이 67.4%, 배반포기로의 배발달율은 13.6% 보다 낮게 나타났고, 또한 산양의 동종간 핵이식란배아의 분열율 81%, 상실배와 배반포기로의 발달률이 54.7% 보다 낮게 나타났다. 이러한 결과로 이종간의 이식은 많은 잇점에도 불구하고 아직은 낮은 배발달률을 보이고 있어 이에 대한 핵이식 조건 및 체외배양 조건 등 많은 부분에서의 추가적인 연구가 필요한 것으로 사료된다.

• 한국안광학회지
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• 제18권4호
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• pp.373-383
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• 2013

목적: 본 연구는 저소득층 분류에 따른 학동기 아동의 굴절력을 분석하였다. 방법: 영천지역 17개 초등학교 저소득층 112명과 보건복지부 산하 질병관리본부에서 시행한 2010 국민건강영양조사 자료의 -6.00 D 이하의 중등도 근시자 중 저소득층 아동을 대상으로 굴절력을 비교 분석하였으며, 설문을 통해 저소득층 단계에 따른 시력 분석과 만족도를 알아보았다. 결과: 전국 소득 최하위군 아동의 우안 등가구면 굴절력은 -1.99 D, 좌안 등가구면 굴절력은 -1.81 D, 전국 소득 최상위군 아동의 우안 등가구면 굴절력은 -1.26 D, 좌안 등가구면 굴절력은 -1.21 D, 영천지역 저소득층 가정의 아동 우안 등가구면 굴절력은 -1.85 D, 좌안 등가구면 굴절력은 -1.81 D로 조사되었다. 고아의 우안 등가구면 굴절력은 -2.75 D, 좌안 등가구면 굴절력은 -2.42 D, 한부모가정 아동의 우안 등가구면 굴절력은 -2.10 D, 좌안 등가구면 굴절력은 -1.96 D, 두 부모가 모두 있는 가정의 아동 우안 등가구면 굴절력은 -1.75 D, 좌안 등가구면 굴절력은 -1.73 D로 조사되었다. 결론: 학동기 아동의 시력에 대한 관심 부족은 근시유발의 한 요인으로 이어질 수 있으며, 이 시기의 부모와 선생님의 역할은 매우 크다. 그러나 저소득층은 부모의 역할이 제한적이므로 시력관리의 사각지대에 위치한 저소득층 아동의 시력 저하를 방지하기 위한 제도적 장치와 사회적 관심이 더욱 필요할 것으로 판단된다.

• Journal of Korean Neurosurgical Society
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• 제65권1호
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• pp.96-106
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• 2022

Objective : The most common complication of anterior cervical discectomy and fusion (ACDF) is cage subsidence and maintenance of disc height affects postoperative clinical outcomes. We considered cage subsidence as an inappropriate indicator for evaluating preservation of disc height. Thus, this study aimed to consider patients with complications such as reduced total disc height compared to that before surgery and evaluate the relevance of several factors before ACDF. Methods : We retrospectively reviewed the medical records of 40 patients who underwent stand-alone single-level ACDF using a polyetheretherketone (PEEK) cage at our institution between January 2012 and December 2018. Our study population comprised 19 male and 21 female patients aged 24-70 years. The minimum follow-up period was 1 year. Twenty-seven patients had preoperative bone mineral density (BMD) data on dual-energy X-ray absorptiometry. Clinical parameters included sex, age, body mass index, smoking history, and prior medical history. Radiologic parameters included the C2-7 cobb angle, segmental angle, sagittal vertical axis, disc height, and total intervertebral height (TIH) at the preoperative and postoperative periods. Cage decrement was defined as the reduction in TIH at the 6-month follow-up compared to preoperative TIH. To evaluate the bone quality, Hounsfield unit (HU) value was calculated in the axial and sagittal images of conventional computed tomography. Results : Lumbar BMD values and cervical HU values were significantly correlated (r=0.733, p<0.001). We divided the patients into two groups based on cage decrement, and 47.5% of the total patients were regarded as cage decrement. There were statistically significant differences in the parameters of measuring the HU value of the vertebra and intraoperative distraction between the two groups. Using these identified factors, we performed a receiver operating characteristic (ROC) curve analysis. Based on the ROC curve, the cut-off point was 530 at the HU value of the upper cortical and cancellous vertebrae (p=0.014; area under the curve [AUC], 0.727; sensitivity, 94.7%; specificity, 42.9%) and 22.41 at intraoperative distraction (p=0.017; AUC, 0.722; sensitivity, 85.7%; specificity, 57.9%). Using this value, we converted these parameters into a bifurcated variable and assessed the multinomial regression analysis to evaluate the risk factors for cage decrement in ACDF. Intraoperative distraction and HU value of the upper vertebral body were independent factors of postoperative subsidence. Conclusion : Insufficient intraoperative distraction and low HU value showed a strong relationship with postoperative intervertebral height reduction following single stand-alone PEEK cage ACDF.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2303-2309
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• 2007

Expressed protein ligation (EPL) technique, joining recombinantly expressed proteins to polypeptides, has been widely adopted for addressing various biological questions and for drug discovery. However, joining two recombinant proteins together is sometimes difficult when proteins are expressed insoluble and unrefoldable, because ligation-active proteins via intein-fusion are obtainable when they are folded correctly. We overcame this limitation coexpressing target protein with additional methionine aminopeptidase (MAP) which enhances removal of the initiation methionine of recombinantly expressed protein. Our approach demonstrated that two domains of 46 kDa 5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase, a target of herbicide glyphosate, were successfully joined by native chemical ligation, although its C-terminal domain was expressed as an inclusion body. The intein-fused N-terminal fragment of EPSP synthase (EPSPSN, residues 1-237) was expressed and the ligation-active thioester tagged N-terminal fragment (EPSPSN-thioester) was purified using a chitin affinity chromatography and mercapto-ethanesulphonate (MESNA) as intein thiolysis reagent. Its Cterminal fragment (EPSPSC, residues Met237-238CYS-427), expressed as an inclusion body, was prepared from an additional MAP-expressing strain. Protein ligation was initiated by mixing ~1 mM of EPSPSN-thioester with ~2 mM of EPSPSCCYS (residues 238CYS-427). Also we found that addition of 2% thiophenol increased the ligation efficiency via thiol exchange. The ligation efficiency was ~85%. The ligated full-length EPSP synthase was dissolved in 6 M GdHCl and refolded. Circular dichroism (CD) and enzyme activity assay of the purified protein showed that the ligated enzyme has distinct secondary structure and ~115% specific activity compared to those of wild-type EPSP synthase. This work demonstrates rare example of EPL between two recombinantly expressed proteins and also provides hands-on protein engineering protocol for large proteins.