• 한국식품영양과학회지
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• 제33권3호
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• pp.571-575
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• 2004

대장균 O157:H7의 백신 생산을 위해서 purity가 높은 lipopolysacharride 분리, 정제를 위한 실험을 실시하였다. 대장균 O157:H7 균주를 확인하기 위해서 shiga toxin을 생산할 수 있는 60 MDa plasmid를 분리하였고, PCR법에 의해 E. coli O157:H7 shiga-like toxin(Stx) 1, 2의 stx gene을 증폭하여 E. coli O157:H7의 특징 (130 bp, 346 bp)을 확인하였다. E. coli O157:H7 LPS의 분리 정제는 페놀추출, 에탄올 분획 및 gel filtration의 간단한 방법을 사용하였다. 마지막으로 SDS-PAGE와 silver nitrate 염색을 이용하여 LPS의 purity를 확인하였다.

• 한국수산과학회지
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• 제26권6호
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• pp.529-537
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• 1993

가다랭이 안와유로부터 docosahexaenoic acid(DHA)를 정제하기 위해 기존의 방법들을 적용하여 비교 검토하고, DHA의 효과적인 정제를 위해 조작방법을 개량하였다. 가다랭이 안와조직의 총지질은 $55.4\%$였으며, 이 중 DHA는 $23.7\%$였다. 저온분별결정법과 요소결정법을 적용한 결과 순도에서 각각 약 $46\%$ 및 $61\%$의 DHA가 얻어졌다. 이들 방법들은 순도면에서는 다소 떨어지나, 정제조작이 단순하여 다량의 DHA 분리에 적합하였다. 질산은 수용액법은 상기 2가지 방법에 비하여 순도면에서는 약간 개선되었으나, 회수율이 대단히 낮았다($10\%$ 이하). 질산은 함침 실리카 칼럼 크로마토그래피법은 고순도 DHA의 정제방법으로써 적합하였다(순도 $98\%$ 이상, 회수율 $90\%$ 이상). 결과적으로 저온분별결정법과 질산은 함침 실리카 칼럼 크로마토그래피법을 조합한 개량법(2단계 정제법)이 가다랭이 안와유로부터 고순도 DHA($99.9\%$)의 정제를 위한 가장 효과적인 방법으로 평가되었다.

• Restorative Dentistry and Endodontics
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• 제37권1호
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• pp.41-49
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• 2012

Objectives: The internal adaptation of composite restorations with or without resin modified glass ionomer cement (RMGIC) was analyzed non-destructively using Microcomputed tomography (micro-CT). Materials and Methods: Thirty intact human teeth were used. The specimens were divided into 3 groups. In the control group, the cavities were etched with 10% phosphoric acid for 15 sec. Composite resin was filled into the cavity without adhesive. In group 1, light cured glass ionomer cement (GIC, Fuji II LC, GC) was applied as a base. The cavities were then etched, bonded, light cured and filled with composites. In group 2, the cavities were then etched, bonded, light cured and filled with composites without base application. They were immersed in a 25% silver nitrate solution. Micro-CT was performed before and after mechanical loading. One-way ANOVA with Duncan analysis was used to compare the internal adaptation between the groups before or after loading. A paired t-test was used to compare internal adaptation before and after mechanical loading. All statistical inferences were made within the 95% confidence interval. Results: The silver nitrate solution successfully penetrated into the dentinal tubules from the pulp spaces, and infiltrated into the gap between restoration and pulpal floor. Group 2 showed a lower adaptation than the control group and group 1 (p < 0.05). There was no significant difference between the control group and group 1. For all groups, there was a significant difference between before and after mechanical loading (p < 0.05). Conclusions: The internal adaptation before and after loading was better when composites were bonded to tooth using adhesive than composites based with RMGIC.

• Animal Systematics, Evolution and Diversity
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• 제37권4호
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• pp.280-286
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• 2021

During a field survey on Korean coastal marine waters, two ciliates belonging to the genera Pseudovorticella Foissner & Schiffmann, 1975 and Frontonia Ehrenberg, 1838 in the class Oligohymenophorea de Puytorac et al., 1974, were collected. Even though the two genera are very common in the aquatic ecosystems, they had been superficially studied in Korean habitats. Using the observation of living cells and specimens impregnated by protargol, silver carbonate, and silver nitrate, two newly recorded ciliate are identified as P. paramarina Sun, Ji, Warren & Song, 2009 and F. ocularis Bullington, 1939. A brief diagnosis, remark, and comprehensive micrographs are provided for each species.

• 자원리싸이클링
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• 제30권2호
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• pp.39-45
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• 2021

폐 태양광전지 처리과정에서 은은 실리콘 및 알루미늄을 회수 위해 제거 하거나 처리하지않고 버리고있는 현실이다. 경제적 및 환경 보호 측면에 폐 태양광전지부터 은의 회수 중요하다고 판단함. 선행연구에서 1 mol/L 질산, 반응온도 70도, 반응시간 2h로 폐 태양광전지부터 Ag, Al을 침출 하었다. 이 침출액으로부터 은을 회수하기 위해 추출제 LIX63 및 탈거제 암모니아수 이용하였다. 추출 및 탈거 효율에 영향 미치는 조건: 침출액 pH, 금속이온 농도, 추출제의 농도, A/O ratio(수상 및 유기상 부피비율), 탈거제 농도 및 탁거과정에서 A/O ratio등을 변화시켜 조차하였다. McCabe-Thiele plots로부터 Ag(I)의 추출 및 탈거에 대한 이론 단수를 구하였으며, 향류 다단 모의 추출 시험을 통해 Ag(I)의 추출과 탈거에 대한 효율이 각각 >99.99%, 98.9% 이었다. Ag(I)와 Al(III)의 순도는 각각 99.998% 와 99.99%이었으며, 질산 침출액으로부터 Ag(I)및 Al(III)을 회수하기 위한 공정도를 제안하였다.

• 한국분말재료학회지
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• 제15권6호
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• pp.466-470
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• 2008

Experiments with a URT-0.5 accelerator (0.5 MeV, 50 ns, 1 kW) generating a nanosecond electron beam for irradiation of silver nitrate in various liquid solutions (water and toluene) were performed with the aim of producing silver nanopowders. A radiochemical reaction allows making weakly agglomerated pure Ag powders with particles of 10-15 nm and 30-50 nm in size by irradiation in toluene and water respectively. The injection of the nanosecond electron beam energy to the solution is optimal. As the absorbed dose increases, the output of the radiochemical reaction does not grow, but more agglomerated powders are synthesized.

• Elastomers and Composites
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• 제54권3호
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• pp.252-256
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• 2019

Fullerene oxide[$C_{60}(O)_n$, ($n{\geq}1$)] was synthesized by dissolving fullerene[$C_{60}$] and 3-chloroperoxybenzoic acid in toluene under refluxing condition for 5 h. Hybrid fullerene oxide-silver nanoparticle composites were synthesized by dissolving fullerene oxide and silver nitrate[$AgNO_3$] in diethylene glycol under ultrasonic irradiation for 3 h. The synthesized hybrid nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, and ultraviolet-visible[UV-vis] spectroscopy. The catalytic activity for the reduction of various nitroanilines[NAs] was identified by UV-vis spectrophotometer. The efficiency of the catalytic reduction by the synthesized hybrid nanocomposites has an order of 4-NA > 2-NA > 3-NA.

• Macromolecular Research
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• 제17권9호
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• pp.688-696
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• 2009

In this study, a new class of polyurethane (PU) nanofibers containing silver (Ag) nanoparticles (NPs) was synthesized by electrospinning. A simple method that did not depending on additional foreign chemicals was used to self synthesize the silver NPs in/on PU nanofibers. The synthesis of silver NPs was carried out by exploiting the reduction ability of N,N-dimethylformamide (DMF), which is used mainly to decompose silver nitrate to silver NPs. Typically, a sol-gel consisting of $AgNO_3$/PU was electrospun and aged for one week. Silver NPs were created in/on PU nanofibers. SEM confirmed the well oriented nanofibers and good dispersion of pure silver NPs. TEM indicated that the Ag NPs were 5 to 20 nm in diameter. XRD demonstrated the good crystalline features of silver metal. The mechanical properties of the nanofiber mats showed improvement with increasing silver NPs content. The fixedness of the silver NPs obtained on PU nanofibers was examined by harsh successive washing of the as-prepared mats using a large amount of water. The results confirmed the good stability of the synthesized nanofiber mats. Two model organisms, E. coli and S. typhimurium, were used to check the antimicrobial influence of these nanofiber mats. Subsequently, antimicrobial tests indicated that the prepared nanofibers have a high bactericidal effect. Accordingly, these results highlight the potential use of these nanofiber mats as antimicrobial agents.

• Advances in nano research
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• 제6권2호
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• pp.183-200
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• 2018

In the present study silver nanoparticles (AgNPs) were successfully synthesized using aqueous extract of Sargassum muticum. The aqueous extract (10%) treated with 1 mM silver nitrate solution resulted in the formation of AgNPs and the surface plasmon resonance (SPR) of the formed AgNPs was recorded at 360 nm using UV-Visible spectrophotometer. The molecules involved in the formation of AgNPs were identified by Fourier transform infrared spectroscopy (FT-IR), surface morphology was studied by using scanning electron microscopy (SEM), SEM micrograph clearly revealed the size of the AgNPs was in the range of 40-65 nm with spherical, hexagonal in shape and poly-dispersed nature, and X-ray diffraction spectroscopy (XRD) was used to determine the crystalline structure. High positive Zeta potential (36.5 mV) of formed AgNPs indicates the stability and XRD pattern revealed the crystal structure of the AgNPs by showing the Bragg's peaks corresponding to (111), (200), (311) and (222) planes of face-centered cubic crystal phase of silver. The synthesized AgNPs exhibited effective anticancerous activity (at doses 25 and $50{\mu}g/ml$ of AgNPs) against Breast cancer cell line (MCF7).

• 자원리싸이클링
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• 제10권5호
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• pp.22-28
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• 2001

방사성 유기 혼합폐기물의 저온 분해공정인 MEO(Mediated Electrochemical Oxidation) 공정에서 발생하는 폐액으로부터 Ag를 화학적으로 회수하는 연구를 수행하였다. 고농도 질산용액과 함에 존재하는 $AgNO_3$를 HCl과 반응시켜 AgCl 침전물로 회수하였다. 이 때 HCl 최적 반응 당량비는 $AgNO_3$비해 1% 초과하였으며 100% 침전시킬 수 있었다. AgCl은 알카리 분위기에서 과산화수소와 반응시켜 순수 Ag금속으로 환원됨을 알 수 있었고, Ag금속의 환원 반응시 용액의 pH는 12.8~13.0의 범위가 적당하였다.