• 대한방사성의약품학회지
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• 제2권1호
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• pp.17-21
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• 2016

Alkali metal fluoride sources (MFs) such as potassium fluoride (KF) have been widely used as a fluoride source in the nucleophilic displacement reaction. However, they have low solubility and nucleophilicity in most of the organic solvents. Bulky fluoride sources such as tetrabutylammonium fluoride (TBAF) were substituted for MFs to improve these properties. However, hygroscopic property of TBAF makes it less convenient for handling as well as its strong basic property can make the side-reaction occur. Recently, novel fluoride sources have been developed to solve these problems. In this paper, we would like to introduce coordinated fluoride sources as a new fluoride sources such as tetrabutylammonium tetra(t-butyl alcohol)-coordinated fluoride, crown ether metal complex fluoride, and various bulky alcohols coordinated fluoride complexes. In particular, bulky alcohol coordinated fluoride source could generated by the controlled hydrogen-bonded of fluoride with alcohols and these fluoride sources have better stability and reactivity with showing low hygroscopic property. The study of these fluoride sources will help to understand the characteristic of [$^{18}F$]fluoride for increasing the radiochemical yield in the [$^{18}F$]radiofluorination.

• 약학회지
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• 제44권2호
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• pp.149-154
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• 2000

Flavin mononucleotide (1,4-butanediamine) Pt(II) complex (7FMN) was synthesized and screened anticancer activity [J. Pharm. Soc. Korea 43(6),762-770 (1999)]. 7FMN have good water solubility and moderate anticancer activiy In this paper cell-cycle specificity and nephrotoxicity were studied. Interaction of DNA with cisplatin and synthesized 7FMN was analyzed by flow cytometry and showed G2 arrest in L1210 cell line. It means that cell-cycle on L1210 was inhibit in S phase by cisplatin and 7FMN. In order to biochemically analyze nephrotoxicity of cisplatin and 7FMN, after injecting each agent intraperitoneally, blood was exsanguinated after 6 hours, 1 day, 3 days and 7 days, respectively. Then, serum was separated from the blood. The serum level of BUN, creatinine and uric acid in cisplatin and 7FMN administated mice (25~35 g, ICR strain, a dose each 8,12 and 16 times of the $IC_{50}$/ value, cisplatin; 7 times) were determined by autochemistry analyzer. In cisplatinadministered mice group, BUN level was elevated than normal control group at 3rd day and repaired at 7th day. In 7FMN administrated group was not elevated. Creatinine and uric acid level were no difference with the normal control group. Therefore synthesized 7FMN is less toxic than cisplatin in nephrotoxiciaty.

• 한국지하수토양환경학회지:지하수토양환경
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• 제23권6호
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• pp.1-8
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• 2018

In this study, formaldehyde and benzene were selected as the arbitrary chemicals in accidental leakage to environment, and their physicochemical and biological characteristics and toxicity were studied. Also, the fate of these chemicals in soil and groundwater was studied based on the results of previous studies. They can be released into the atmosphere as gas or vapor phase, which then can be photochemically degraded. Since they have relatively high water solubility, they are likely to have high mobility in water and soil. Volatilization of these chemicals from soil is affected by the soil moisture content. Biodegradation of formaldehyde and benzene is one of the important pathways as well. Therefore, it is necessary to study the environmental impacts of leakage accidents of flammable chemicals such as formaldehyde and benzene. Further research on the fate of flammable chemicals in the environment is needed to take appropriate response actions to leakage accidents of flammable chemicals, and this will contribute to the development of practical guidelines to cope with leakage accidents.

• 한국기계가공학회지
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• 제18권2호
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• pp.91-95
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• 2019

A new experimental approach is proposed to detect a specific polymer dissolved in a liquid. Distinctive optical properties were found using a laser scattering technique when there is a polymer compound with almost no difference in optical properties (index of refraction) in a liquid phase. The index of refraction, which determines the refraction of light, is obtained by dissolving PCL and PLA. The used samples are biodegradable materials with similar properties and dissolved in a mixture of Chloroform 7: Methanol 3. To predict the optical properties, a 632-nm diode laser was used as the light source of the device, and an integrating sphere was used as the light receiver. Although PCL and PLA had a similar index of refraction of 1.46-1.48, the dissolved PCL showed a relative transmittance of 43%, and the dissolved PLA had a relative transmittance of 34%. The difference in optical properties of the pure polymer compound in the solid state or liquid state is not significantly different, and the difference in the dissolved state in the specific solvent is remarkable because the solubility differs in a specific solution and is randomly distributed.

• Steel and Composite Structures
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• 제45권2호
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• pp.281-291
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• 2022

Surmounting complexities in analyzing the mechanical parameters of concrete entails selecting an appropriate methodology. This study integrates a novel metaheuristic technique, namely satin bowerbird optimizer (SBO) with artificial neural network (ANN) for predicting uniaxial compressive strength (UCS) of concrete. For this purpose, the created hybrid is trained and tested using a relatively large dataset collected from the published literature. Three other new algorithms, namely Henry gas solubility optimization (HGSO), sunflower optimization (SFO), and vortex search algorithm (VSA) are also used as benchmarks. After attaining a proper population size for all algorithms, the Utilizing various accuracy indicators, it was shown that the proposed ANN-SBO not only can excellently analyze the UCS behavior, but also outperforms all three benchmark hybrids (i.e., ANN-HGSO, ANN-SFO, and ANN-VSA). In the prediction phase, the correlation indices of 0.87394, 0.87936, 0.95329, and 0.95663, as well as mean absolute percentage errors of 15.9719, 15.3845, 9.4970, and 8.0629%, calculated for the ANN-HGSO, ANN-SFO, ANN-VSA, and ANN-SBO, respectively, manifested the best prediction performance for the proposed model. Also, the ANN-VSA achieved reliable results as well. In short, the ANN-SBO can be used by engineers as an efficient non-destructive method for predicting the UCS of concrete.

• 한국자기학회지
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• 제4권3호
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• pp.226-232
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• 1994

철-희토류 화합물인 Sm-Fe 이원계에서 조성식 $SmFe_{7+x}M_{x}(M=Mo,\;V,\;Ti)$ 화합물을 급속냉각기술로 제조하여 강자성을 나타내는 새로운 자성상인 ${Sm(Fe,\;M)}_{7}$을 합성하였다. Sm-Fe 이원계에 제 2의 천이원소 Mo, V 또는 Ti를 첨가함으로써, ${Sm(Fe,\;M)}_{7}$ 자성상은 큐리온도(Tc)가 $T_{c}=355^{\circ}C$에 달했으며 x=0.8과 1.0 사이에서 $SmFe_{7+x}M_{x}(M=Mo,\;V,\;Ti)$의 고유보자력 ($_{i}H_{c}$)이 3~6 kOe를 갖는 신 자성상을 제조하였다. ${Sm(Fe,\;M)}_{7}$ 상은 급냉응고 된 상태에서나 열처리 후에도 변함없이 안정하였으며 오히려 급냉상태에서 보다 우수한 강자기 특성을 보였다. ${Sm(Fe,\;M)}_{7}$은 육방정계 결정구조를 갖는 능방정계이며 P6/mmm Space Group에 속하는 것으로 판명되었다. ${Sm(Fe,\;M)}_{7}$ 자성상이 고보자력을 나타내는 원천적인 이유는 급속냉각에 의하여 결정입도가 $2000~8000\;{\AA}$의 미립자로 형성되기 때문이며, 높은 규리온도를 보이는 까닭은 급속냉각에 의해 제 2의 천이원소인 Mo, V 또는 Ti의 Fe에 대한 고용도가 평형상태에서 보다 월등히 높아져 자기변환온도를 상승하게 하였기 때문이다.

• Nuclear Engineering and Technology
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• 제31권3호
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• pp.335-343
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• 1999

The effects of N $b_2$ $O_{5}$ and oxygen potential on the densification and grain growth of U $O_2$ fuel have been investigated.0.3 wt% N $b_2$ $O_{5}$ -doped U $O_2$fuel pellets were sintered at 1$700^{\circ}C$ for 4 hours in sintering atmospheres which have various ratios of $H_2O$ to $H_2$ gas. Compared with those of undoped U $O_2$ pellets, the sintered density and grain size of the 0.3 wt% N $b_2$ $O_{5}$ -doped U $O_2$ pellet increase under the $H_2O$/ $H_2$ gas ratio of 5.0$\times$10$^{-3}$ to 1.0$\times$10$^{-2}$ and under the $H_2O$/ $H_2$gas ratio of 5.0$\times$10$^{-3}$ to $1.5\times$10$^{-2}$ , respectively. The sintering of U $O_2$fuel pellets containing 0.1 wt% to 0.5 wt% N $b_2$ $O_{5}$ was carried out at 168$0^{\circ}C$ for 4 hours. The enhancing effect of N $b_2$ $O_{5}$ on the sintered density and grain size becomes larger as the N $b_2$ $O_{5}$ content increases. The solubility limit of N $b_2$ $O_{5}$ in U $O_{2}$ seems to be between 0.3 wt% and 0.5 wt%, and beyond the solubility limit the second phase whose composition corresponds near to N $b_2$U $O_{6}$ is precipitated on grain boundary. The enhancement of densification and grain growth in U $O_2$ is attributed to the increased concentration of a uranium vacancy which is formed by the interstitial N $b^{4+}$ ion in the U $O_2$ lattice.

• The Korean Journal of Ceramics
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• 제1권2호
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• pp.91-95
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• 1995

Polycrystalline bismuth- and aluminum- substituted dysporsium and yttrium iron garnet (Bi2R3-xAlyFe5-yO12, R=Dy or Y, $0\leqx\leq3, \; 0\leqy\leq3$) films have been prepared by pyrolysis. The crystallization temperatures, the solubility limit of bismuth ions into the garnet phase, and magnetic and magneto-optic properties of the films have been investigated as a function of bismuth and aluminum concentration. It was found that the crystallization temperatures as a function of bismuth and aluminum concentration. It was found that the crystallization temperatures of these films rapidly decreased as bismuth concentration. It was found that the crystallization temperatures of these films rapidly decreased as bismuth concentration (x) increased up to x=1.5 and then remained temperatures of these films rapidly decreased as bismuth concentration (x) increased up to x=1.5 and then remained unchanged at x>1.5, whereas, showed no changes as aluminum concentration (y) increased up to y=1.0 and then gradually increased at y>1.0. The solubility limit of bismuth ions was x=1.8 when y=0 but increased to x=2.3 when y=1.0. It was demonstrated that the magnetic and magneto-optic properties of the dysprosium iron garnet films could be tailored by bismuth and aluminum substitution suitable for magneto-optic recording as follows. The saturation magnetization and coercivity data obtained for the films indicated that the film composition at which the magnetic compensation temperature became room temperature was y=1.2 when x=1.0. Near this composition the coercivity and the squareness of the magnetic hysteresis loop of the films were several kOe and unit, respectively. The Curie temperatures of the films increased with the increase of x but decreaed with the increase of y, and was 150-$250^{\circ}C$ when x=1.0 and y=0.6-1.4. The Faraday rotation at 633 nm of the films increased as x increased but decreased as y increased, and was 1 deg/$\mu\textrm{m}$ when x=1.0 and y=1.0. Based on the data obtained, the appropriate film composition for magneto-optic recording was estimated as near x=1.0 and y=1.0 or $BiDy_2AlFe_4O_{12}$.

• Korean Chemical Engineering Research
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• 제55권3호
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• pp.369-378
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• 2017

혈관 내피세포 성장인자(Vascular endotherial growth factor, VEGF)는 혈관 투과율 조절이나 혈관 생성에 관련된 단백질로 임상용으로 쓰일 가능성이 높다. 이 단백질은 고순도와 고효율로 상업적으로 대량생산이 필요하다. 유비퀴틴 융합 단백질로 온화한 조건에서 용해시키기 위해 다양한 조건을 연구하였고, pH와 변성제 변화를 시도하였다. BL21 (DE3) 대장균 숙주세포에서 pET28-a 벡터를 사용하여 재조합 대장균을 제조하여, 20 L의 회분식 배양으로 14 g/L농도의 세포배양을 하였다. 발효 후UBP1 효소 분해와 재접힘 단계를 포함한 4단계의 크로마토그래피 공정으로 구성된 정제공정으로 VEGF를 정제하였다. 유비퀴틴 융합단백질로 2 M 요소와 pH10 온화한 조건에서 VEGF의 정제가 가능하였다. 2번의 Ni-affinity 크로마토그래피컬럼을 이용하여 고효율의 재접힘과 이합체화 공정을 수행하였다. DEAE (Diethyl Amino Ethyl) 음이온 교환 컬럼을 통하여 변형체(multimeric, misfolded)단백질과 endotoxin을 제거 할 수 있었다. 젤 여과 크로마토그래피를 이용하여 dimer와 monomer를 분리 하여 이합체화 VEGF를 제조하였다. 최종 VEGF의 특성분석을 SDS-PAGE (Soidum Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis) 전기영동, RP-HPLC (Reversed Phase High Performance Liquid Chromatography)으로 하여 순도 97% (RP-HPLC기준)를 얻었다.

• 공업화학
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• 제26권6호
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• pp.719-724
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• 2015

아이소리퀴리티게닌은 감초의 구성 성분으로서 항산화, 항균 활성과 같은 다양한 약리학적 활성을 가지고 있는 소수성 물질이다. 본 연구에서는 소수성 약물의 용해도를 증진시키기 위해서 아이소리퀴리티게닌/2-하이드록시프로필-베타사이클로덱스트린 복합체를 freeze-drying 방식으로 제조하였고, 상평형 연구, DSC, SEM, 1H NMR을 통하여 그 특성을 확인하였다. 항균 활성은 Staphylococcus aureus (S. aureus)와 Escherichia coli (E. coli)에 대해 broth dilution assay 측정법으로 최소성장억제농도(minimum inhibitory concentration, MIC)를 확인하였다. 상평형 연구를 통해 아이소리퀴리티게닌/2-하이드록시프로필-베타사이클로덱스트린 복합체는 1 : 1 몰비율로 형성되는 것을 확인하였다. S. aureus와 E. coli에 대한 MIC는 아이소리퀴리티게닌/2-하이드록시프로필-베타사이클로덱스트린 복합체의 경우 각각 1.25 및 2.5 mg/mL이었으며, free한 아이소리퀴리티게닌은 각각 5, 5 mg/mL로 아이소리퀴리티게닌/2-하이드록시프로필-베타사이클로덱스트린 복합체가 더 높은 항균 활성을 나타내었다. 이는 아이소리퀴리티게닌/사이클로덱스트린 복합체가 식품 및 화장품 산업에서 합성 방부제를 대체하고 천연 방부제로서 응용 가능성이 있음을 시사한다.