• 공업화학
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• 제35권1호
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• pp.37-41
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• 2024

열대성 과일로 널리 재배되고 있는 코코넛(coconut)의 독특한 껍질(shell)은 과육 섭취 후 얻어지는 부산물로 활용 가치가 클 것으로 기대된다. 이 코코넛 껍질을 전도성 고분자와 혼합하여 복합소재를 간단한 방식으로 제조하고 섭씨 600도 정도의 상대적 저온에서 탄화하여 수득되는 소재의 전기화학적 특성 및 활용 가능성을 고찰하였다. 먼저, 외형적 요소를 주사전자현미경(scanning electron microscope, SEM)으로 관찰하였다. 탄소의 미세구조를 라만(Raman) 분광 분석을 통하여 추론하였다. 전기전도 가능성을 간단한 옴의 관계(Ohmic relation)를 통하여 확인하였다. 나아가, 탄화된 재료가 리튬 이차 전지의 음극(anode) 소재로 활용될 수 있는지 여부를 반쪽 전지(half-cell) 충방전(charge/discharge) 테스트를 통해 살펴보았으며, 최대 충전 용량은 약 750 mAh로 높게 나타났으나, 충전이 진행됨에 따라 빠른 감소를 보였다. 본 연구는 향후 목질계 폐기물의 활용에 대한 중요한 정보를 제공할 것이다.

• 생명과학회지
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• 제34권6호
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• pp.365-376
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• 2024

이 연구는 여러 종류의 암세포주(A-549, AGS, HCT-116, MDA-MB-231 및 U 87-MG)와 정상세포주(MRC-5 및 MSC)에 RNA를 DNA로 전환시킬 수 있는 역전사 효소의 억제 처리 후 세포의 성장에 미치는 영향을 비교 조사하였다. 각 세포주에 efavirenz (EFA) 역전사 효소 억제제를 1주일 동안 처리하였을 때, 세포 성장의 반억제농도(IC₅₀) 값은 암세포주보다 정상세포주에서 더 높은 값을 나타냈다. 결정된 IC₅₀ 값에 따라 15 µM 농도로 EFA를 1주일 동안 처리하였을 때, 역전사 효소 및 말단소립 복원 효소의 활성은 EFA 처리군에서 비처리군에 비하여 유의적으로(p<0.05) 감소하였다. 그러나, 역전사 효소 및 말단소립 복원효소의 활성은 정상세포주에서는 검출되지 않았다. 15 µM EFA를 처리한 후, 암세포주와 정상세포주에서 세포성장율을 비교하였을 때, EFA 처리는 모든 세포의 성장을 억제하였는데, 정상세포주보다 암세포주에서 세포의 성장율이 현저하게(p<0.05) 감소하였다. 또한, 역전사 효소의 억제가 세포의 노화 및 사멸에 미치는 영향을 분석하기 위해 노화 관련 ß-galactosidase 효소의 활성을 분석하였을 때, EFA 처리가 노화관련 효소 활성이 점점 증가하는 것으로 보아, EFA 역전사 효소의 처리는 세포 노화 및 세포 사멸을 유도하는 것을 알 수 있었다. 이상의 결과를 바탕으로, 역전사 효소의 억제는 정상세포보다는 암세포의 성장을 더 억제하는 것을 알 수 있었지만, 항암치료 등에서 응용되기 위해서는 세포에서 역전사 효소의 기능과 역할에 대해서는 좀 더 심도있는 연구가 필요할 것으로 생각된다.

• 약학회지
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• 제50권1호
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• pp.52-57
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• 2006

The activation of cyclin dependent kinase 4 (CDK4) is found in more than half of all human cancers. Therefore CDK4 is an attractive target for the development of a novel anticancer agent. For mass screening of CDK4 inhibitor, we set up in vitro kinase assay for CDK4 activity using a cyclin D1-CDK4 fusion protein, which is constitutively active and exhibits enhanced stability. From the screening of representative compound library of Korea Chemical Bank, we found that 7-chloro-4-nitro-benzo[1,2,5]oxadiazole 1-oxide (FBP-1248) selectively inhibited CDK4 activity in vitro by ATP competitive manner. This compound prevented the phosphorylation of retinoblatsoma tumor suppressor protein, Rb, and inhibited cell growth through cell cycle arrest. In summary, we developed an efficient assay system for CDK4 activity in vitro and identified the CDK4 inhibitory compound, FBP-1248.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.275-279
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• 2005

Insect cell transformants, stably expressing human $GFP_{uv}-{\beta}1$, 3-N-acetylglucosaminyltransferase 2 $({\beta}3GnT2)$ as the green fluorescent protein $(GFP_{uv})-fused$ protein, were efficiently isolated on Western blot by the quantification of the densitometric intensity of the fusion protein. From almost 150 transformants containing the fusion gene linked to three different types of signal sequence, two transformants, Tn-pXme4a and -pX28a, were successfully selected, showing 8.3 and 8.6 mU/mL ${\beta}3GnT$ activity, respectively. This method requires a screening time almost one-half that required in the isolation of stably transformed cells with high expression levels, and at the same time allows the handling a large number of transformants.

• 대한세포병리학회지
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• 제3권2호
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• pp.52-59
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• 1992

A number of studies have shown the value of fine needle aspiration cytology for the diagnosis of breast lesions, but reports on the comparison of cytologic and histologic variations of breast cancers are few. We reviewed histologically proven 106 breast aspirates with an emphasis on the cytology of ductal carcinomas and of an area of uncertain atypia. Positive and negative predictive values of breast aspiration cytology were 100% On review of the cases originally diagnosed as atypia of uncertain nature (19 %), features more suggestive of malignancy or benignancy were recognizable in most underdiagnosed cases and a half of overdiagnosed cases, respectively. However, indistinguishable atypism also remained. Thirty seven cases out of 53 infiltrating duct carcinomas revealed malignant cytology, with variations in background, cellularity, morphology of cell groups, and extent of isolated tumor cells. When classifying the infiltrating duct carcinomas into scirrhous, solid-tubular, and papillotubular types, scirrhous type frequently appeared as irregularly shaped tight or loose cell clusters, and solid-tubular type as round-margined cell balls.

• 한국미생물·생명공학회지
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• 제21권4호
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• pp.342-347
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• 1993

It was proved that the cell growth followed a photo-inhibition model in light-limited turbidostat cultivation, having 1.06 (1/h) of maximum specific growth rate and 0.00094(kcal/$cm^2$/h) and 0.063 (kcal/$cm^2$/h) as half saturation and light inhibition constants, repectively. ${\beta}$-carotene production showed a growth related porcess. And the activation energy of Dunaliella salina was roughly estimated as 12.36 (kcal/mole) in employing Arrhenius relationship. It should also point out that relatively much porduction of ${\beta}$-carotene was observed at hight light intensity with yieding 1.04 (mg-carotene/g-dry cell/day) of specific product production rate while the cell growth was decreased. The optimal conditions of producing ${\beta}$-carotene in turbiodostat cultivation were as follows: $7.5{\times}10^{-3}$(kcal/$cm^2$/h)of light intensity, 2 (mM) and 50(mM) of nitrate and sodium bicarbonate concentrations and 100(ml/h) of $CO_2$ flow rate.

• 식물분류학회지
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• 제41권3호
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• pp.230-234
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• 2011

While preparing a floristic study of Korean hepatics, we discovered the 4 unrecorded species Alobiellopsis parvifolius, Calypogeia japonica, Hattoria yakushimensis and Nardia subclavata. A. parvifolius is often confused with Solenostoma fusiforme (Steph.) Amak. in appearance, but the former differs by occasional presence of underleaves and a large hyaline outer cells of stem. C. japonica is similar to C. tosana (Steph.) Steph. The former, however, is separated from the latter by 2-3 biconcentric oil-bodies per cell compared to 3-5 grape oil-bodies per cell. H. yakushimensis is a monotypic genus based on a Japanese species. This genus is characterized by unlobed, closely imbricate leaves with margins distinctly incurved and usually pigmented with a reddish purple color. N. subclavata is similar to N. assamica (Mitt.) Amakawa in large underleaves and globular oil-bodies. The former, however, is separated from the latter by convex trigones versus concave trigones, smooth cuticles versus smooth to verrucose cuticles, and oil-bodies occurring in each cell versus occurring in approximately half or fewer leaf cells.

• 한국세라믹학회지
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• 제44권12호
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• pp.715-719
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• 2007

STS444 with or without $La_{0.9}Sr_{0.1}MnO_3$ (LSM)-coating was contacted to $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ (LSCF) cathode on various electrolyte materials and the polarization resistance $(R_p)$ was measured by impedance spectroscopy. By making a symmetric half-cell and contacting only one side of the cathode with the interconnect, the effect of chromium (Cr) poisoning was separated from the aging effects. When the LSCF cathode was contacted with LSM-coated STS (stainless steel), $R_p$ of LSCF was lower than that contacted with the uncoated STS. Impedance patterns measured for the working electrode (W.E.), the counter electrode (C.E.) at $600^{\circ}C$ in air were analyzed. Normalized data of net Cr effect showed that $Ce_{0.9}Gd_{0.1}O_2$ (GDC) electrolyte is more tolerant to the chromium poisoning than $La_{0.9}Sr_{0.1}Ga_{0.8}Mg_{0.2}$ (LSGM) or 8 mol% $Y_2O_3-doped$ $ZrO_2$ (YSZ) electrolytes.

• ALGAE
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• 제22권3호
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• pp.235-240
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• 2007

The red tide-causing flagellate Chattonella anticfua can cause mass fish kills by their clogging in fish gills. Thisstudy examined the nutrient requirements of C. antiqua isolated from Korea. C. anticfua displayed maximum growthat the day five, followed by a decrease in cell density. Nitrate and nitrite were the preferred nitrogen sources, alonewith adenosine diphosphate for phosphorus compounds. In medium that contained ammonium, a significantdecrease in cell density was observed. Half-saturation constants, Ks, calculated from the maximum growth ratewere 4.94 U|M for NC>3 and 0.79 flM for P04. The growth of C. antiqua was not within the function of the N:P ratio (RU= 0.29). With an N:P ratio as low as 10, the increase in cell density was apparent, with a higher division rate. At lev-els above 50 fiM of NaNOg or 8 ;uM of NaHUPCU, the growth rates were somewhat decreased. Phosphate was thelimiting factor for C. antiqua growth since the starvation of phosphate had brought about a rapid decrease in celldensity in semi-continuous culture. Studies about the temporal modification of the efficiency of nitrate or phosphateuptake may be necessary to explain the bloom dynamics of C. antiaua.

• 전자공학회논문지S
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• 제35S권8호
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• pp.21-31
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• 1998

본 논문에서는 복사 네트워크의 멀티캐스트 셀을 적절하게 분배할 수 있는 새로운 분배 알고리즘을 제안한다. 합산기, 분배기, 가상 주소 부호기, 방송 네트워크가 이원적으로 구성된 복사 네트워크는 제안된 분배 알고리즘에 의하여 낮은 번지와 높은 번지가 양분되어 동시에 동작하기 때문에 입력된 셀이 균등하게 처리되어 셀 지연율과 입력 공정성이 개선되고 복잡도가 감소된다. 또한 방송 네트워크로 이진 트리와 Banyan 네트워크로 구성된 확장 Banyan 네트워크를 사용하여 오버플로우 발생 확률을 1/2로 감소 시킨다. 분석 결과 제안된 알고리즘은 입력 버퍼에서 셀 지연율이 확연하게 감소됨을 알 수 있었다.