• BMB Reports
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• 제28권2호
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• pp.100-106
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• 1995

S-adenosylmethionine (SAM) synthetase was purified to homogeneity from soybean (Glycine max) axes. The enzyme was purified 216-fold with a 1.5% yield by ammonium sulfate fractionation, acetone fractionation, ion exchange chromatography with DEAE-sephacel, gel filtration with Sephacryl S-300, and afffinity chromatography with ATP-agarose. The enzyme activity reached a maximum 3 days after germination. SAM synthetase had a subunit molecular weight of 57,000 daltons from a silver stained single band on SDS-PAGE. The molecular weight of the enzyme was 110,000 daltons from Sephacryl S-300 gel filtration. The enzyme was composed of two identical subunits. The $K_m$ values of the enzyme for L-methionine and ATP were 1.81 and 1.53 mM, respectively. The enzymatic activity was not affected by polyamines, agmatine, or SAM analogues, but was inhibited by SAM. The inhibition pattern was showed non-competitive for L-methionine and uncompetitive for ATP. The activity of SAM synthetase was inhibited by thiol-blocking reagents. The enzyme was induced by treatment with $10^{-3}$ M putrescine at germination. Experimental data revealed a possible novel regulation mechanism of polyamine biosynthesis through several endogenous intermediates.

• 분석과학
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• 제24권5호
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• pp.401-405
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• 2011

본 연구는 수용액 중의 발암물질로 규제되고 있는 브롬산 이온($BrO_3^-$)을 제거하는 방법에 관한 것이다. 브롬산 이온은 먹는 물의 정수 과정 중 브롬 이온의 존재 하에 오존 처리과정에서 생성되는 물질이다. 본 방법은 별다른 물리적 화학적 변화의 과정이 필요하지 않고, 활성알루미나를 이용하여 효과적으로 제거할 수 있어 먹는 물 등의 정수에도 유용하게 적용될 수 있다. 브롬산 이온 500 ${\mu}g$/L 농도의 용액을 표면 개질된 산성 활성알루미나를 사용하여 1~2 분 내에 95% 이상 제거하는 효과를 나타내었다.

• 한국응용과학기술학회지
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• 제10권1호
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• pp.57-65
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• 1993

The fatty acid, all $cis-{\Delta}^{5,11,14}-C_{20:3}$, in the Gingko nuts oils, was isolated and, purified by urea-adduct method, silver ion silica gel chromatography and HPLC equipped with reversed phase ${\mu}-Bondapak$ $C_{18}$ column. Its structural elucidation was conducted by IR and $^1H$-, $^{13}C$-NMR technique. The fatty acid composition of seed oils mainly consists of linoleic acid(37.73%), vaccenic acid(18.30%), oleic acid(15.18%), palmitic acid(3.37%), palmitoleic acid(3.37%) and ${\Delta}^5$ NMDB fatty acids(8.50%) in which all $cis-{\Delta}^{5,11,14}-C_{20:2}$ predominates.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2607-2610
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• 2011

Monodispersed Ag/$TiO_2$ core/shell nanoparticles were synthesized in solution via colloid-seeded deposition process using Ag nanoparticles as colloid seeds and $Ti(SO_4)_2$ as Ti-source respectively. Silver nitrate was reduced to Ag nanoparticles with $N_2H_4{\cdot}H_2O$ in the presence of CTAB as stabilizing agent. The titania sols hydrolyzed by the $Ti(SO_4)_2$ solution deposited on the surface of Ag nanoparticles to form the Ag/$TiO_2$ core/shell nanoparticles. Inductively coupled plasma atomic emission spectrometry (ICP-AES) showed low amount of Ag ion leaching from the Ag/$TiO_2$ core/shell nanoparticles. The Ag/$TiO_2$ core/shell nanoparticles indicated excellent antibacterial effects against Escherichia coli and maintained long-term antibacterial property.

• Food Science and Biotechnology
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• 제15권1호
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• pp.107-111
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• 2006

Kernel oils of Lindera erythrocarpa seeds had high level of unusual fatty acid. Picolinyl ester of this unknown fatty acid showed molecular ion at m/z = 317 with other diagnostic ions such as m/z = 151, 191 (40 amu between two peaks), 204, and 218 on GC-MS. Characteristic peak at $720\;cm^{-1}$ appeared in IR spectrum. In $^1H-NMR$ spectrum both methylene protons at C-3 and C-6 resonated at ${\delta}2.309$ and ${\delta}2.012$, and methine protons of double bond resonated in lower magnetic field centered at ${\delta}5.296$ (C-4) and ${\delta}5.387$ (C-5) as multiplet (J = 9.7Hz). In $^{13}C-NMR$, signals at ${\delta}22.669$ and ${\delta}27.048$ were due to C-3 and C-6 of ${\delta}^4$-monoenoic acid. Results obtained from spectroscopic measurements confirmed unknown fatty acid as cis-4-tetradecenoic acid (cis-4-$C_{14:1}$). Main fatty acid components of oils were cis-4-$C_{14:1}$ (44.5-45.1%), oleic acid ($C_{18:1}$), 20.4-21.3%), and lauric acid ($C_{12:0}$, 11.6-12.4%), along with trace amounts of cis-4-$C_{12:1}$ and cis-4-$C_{16:1}$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.339-339
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• 2007

Metal coating on ceramic powder has long been attracting interest for various applications such as superconductor where the brittle nature of high temperature ceramic superconductor was complemented by silver coating and metalloceramics where mechanical property improvement was achieved via electroless plating. More recently it has become of great interest in embedded passive device applications since metal coating on ceramic particles may result in the enhancement of the dielectric properties of ceramic-polymer composite capacitors. In our study, nickel ion-containing solution was used for coating commercial capacitor-grade $BaTiO_3$ powder. After filtering process, the powder was dried and heat-treated in 5% forming gas at $900^{\circ}C$. XRD and TEM were utilized for the observation of crystallization behavior and morphology of the particles. It was found that the nickel coating characteristics were strongly dependent on the several parameters and processing variables, such as starting $BaTiO_3$ particle size, nickel source, solution chemistry, coating temperature and time. In this paper, the effects of these variables on the coating characteristics will be presented in some detail.

• 멤브레인
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• 제31권1호
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• pp.61-66
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• 2021

본 연구는 현재 올레핀/파라핀 분리에서 사용되는 극저온 분리법을 대체하기 위한 촉진수송 분리막에 대한 연구이다. 촉진수송 분리 막을 상업화하기 위해서는 비용 절감 또한 매우 중요한 요소이다. 하지만 많은 연구가 이루어지고 있는 AgBF4는 상대적으로 고가인 은 염이기 때문에 이를 대체하기 위해 비교적 저렴한 AgCF3SO3를 이용하여 PEBAX-2533/AgCF3SO3/Al(NO3)3 복합막을 제조하였다. 분리막의 특성은 SEM, FT-IR, RAMAN을 통해 분석되었으며, 이번 연구를 통해 고분자 매트릭스가 장기 안정성에 영향을 준다는 사실을 확인하였다.

• 한국재료학회지
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• 제24권12호
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• pp.671-676
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• 2014

It is known that bones get damaged by accidents and aging. Since the discovery of Bioglass, various kinds of ceramics have been also found to bond to living bone; some of these ceramics are already being clinically used as bone-repairing materials. In the present study, antibacterial calcium silicate gel ($Ag-30CaO{\cdot}70SiO_2$ gel) was prepared by sol-gel method in order to control the microstructure, which is related to the dissolution rate and induction period of apatite formation in body environment. In addition, biological $Ag-30CaO{\cdot}70SiO_2$ is tested. This was done to impart antimicrobial activity to the $30CaO{\cdot}70SiO_2$. Ag ion was added during sol-gel synthesis to replace the $H_2O$ added during the making of the $30CaO{\cdot}70SiO_2$ gel, which has silver solutions of various concentration. After the sol-gel process, 1N-$HNO_3$ solution was used to wash the gel when synthesizing the gel, in order to maintain the porous structure and remove PEG, water soluble polymers. Then, the apatite forming ability of the sol-gel derived CaO-$SiO_2$ gels was investigated using simulated body fluid (SBF), which had almost the same ion concentration as that of human blood plasma. The gels were analyzed by FT-IR spectroscopy, SEM observation, XRD, and fluorescent microscopy. The apatite was successfully created even after washing the gel; apatite is present in an amorphous state, and was found to affect the concentration of the Ag ion in cells in MC3T3 live & dead assay results. From these results, it is suggested that a good material that can be used to repair defects of nature bone is $Ag-30CaO{\cdot}70SiO_2$ gel.

• 분석과학
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• 제7권2호
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• pp.225-232
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• 1994

$Pb^{2+}$에 대해 $Ag^+$의 높은 추출 선택성이 기대되는 비고리 폴리에테르인 포단드 I-VII을 설계하여 높은 수율로 합성하였다. 포단드 I-VII을 추출제로 이용하여 물/클로로포름계에서 $Ag^+$ 및 $Pb^{2+}$의 피크린산염에 대한 %추출률(%Ex)을 구하였다. 또한 $Ag^+$과 포단드 I-VII과의 착물 형성에 대한 안전도상수(log K)를 전위차 적정에 의해 구하였다. %Ex($Ag^+$)는 치환된 황주개원자 수에 비례하였으나, 황 주개원자가 3개 치환된 포단드 VI(log K:7.65)와 4개 치환된 포단드 VII(log K:9.15)은 모두 100%에 가까운 추출률을 나타내었다. %Ex($Ag^+/Pb^{2+}$)에 있어서는 산소-황 혼합주개 포단드(IV-VII)가 더 큰 값을 나타내었다. 한편, %Ex($Ag^+$) 및 log K의 크기는 황주개자리의 변화에 크게 의존하였는데, 이는 NMR 실험결과 방향족 말단기 사이의 ${\pi}-{\pi}$ 스텍킹 상호작용에 기인한 것으로 생각된다.

• 한국안광학회지
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• 제15권4호
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• pp.361-366
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• 2010

목적: Hollow Cathode Discharge방법을 이용한 HCD 이온플레이팅 장비를 제작하였고, 이 장비를 이용하여 stainless steel 위에 TiN 박막을 질소 가스양을 변화하면서 코팅하였으며, 이때 TiN 박막의 미세색상변화를 분석하였다. 방법: 질소 가스에 대한 TiN박막의 미세색상변화를 광학적으로 관찰하기 위해 분광복사계와 분광광도계를 사용하였고, 질소 가스에 대한 TiN 박막의 성분 변화를 알기위해 XPS로 분석하였다. 결과: 질소가스 120 sccm의 TiN 박막의 CIE 색좌표는 (0.382, 0.372)로 은색과 금색의 혼합색으로 나타나고 질소 가스양이 증가함에 따라 x, y값 둘다 조금씩 커져 금색이 점점 진해지는 것을 알 수 있었다. 또한 분광광도계에 의한 TiN 박막의 반사율에 있어서 질소 가스양이 증가함에 따라 550 nm 파장근처에서의 반사율의 기울기가 대체적으로 점점 커지는 것을 알 수 있었다. 그리고 XPS를 사용하여 Ti scan 한 결과, $N_2$ 성분에서 유래된 458 eV의 조그마한 피크는 조금씩 더 들어가며 TiN 성분에서 유래된 455 eV의 큰 피크는 약간씩 커지는 것을 볼 수 있었다. 결론: 질소 가스양이 120 sccm인 TiN 박막에서는 표면에 있는 TiC 성분과 표면과 내부에 존재하는 $N_2$, TiN 성분으로 인해 은색과 금색의 혼합색으로 나타났으나, 질소 가스양이 증가함에 따라 TiN 성분이 다른 성분에 비해 점점 많아져 금색이 점점 진해진 것으로 유추할 수 있었다.