• BMB Reports
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• v.40 no.4
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• pp.494-500
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• 2007

The endophytic bruchid pest Callosobruchus maculatus causes severe damage to storage cowpea seeds, leading to economical losses. For this reason the use of $\alpha$-amylase inhibitors to interfere with the pest digestion process has been an interesting alternative to control bruchids. With this aim, $\alpha$-amylase inhibitors from baru seeds (Dipteryx alata) were isolated by affinity chromatographic procedures, causing enhanced inhibition of C. maculatus and Anthonomus grandis $\alpha$-amylases. To attempt further purification, this fraction was applied onto a reversed-phase HPLC column, generating four peaks with remarkable inhibition toward C. maculatus $\alpha$-amylases. SDS-PAGE and MALDI-ToF analysis identified major proteins of approximately 5.0, 11.0, 20.0 and 55 kDa that showed $\alpha$-amylase inhibition. Results of in vivo bioassays using artificial seeds containing 1.0% (w/w) of baru crude extract revealed 40% cowpea weevil larvae mortality. These results provide evidence that several $\alpha$-amylase inhibitors classes, with biotechnological potential, can be isolated from a single plant species.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1551-1554
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• 2010

Two diastereomeric chiral stationary phases (CSPs) were applied to the liquid chromatographic resolution of various racemic ${\alpha}$-amino methyl esters, ${\alpha}$-amino N,N-diethylamides and ${\alpha}$-amino N-propylamides. The CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (R,R)-tartaric acid unit as chiral barriers did not show any chiral recognition. In contrast, the CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (S,S)-tartaric acid unit as chiral barriers was found to show excellent chiral recognition especially for the two enantiomers of ${\alpha}$-amino N-propylamides. Some of ${\alpha}$-amino methyl esters and ${\alpha}$-amino N,N-diethylamides were also resolved on the CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (S,S)-tartaric acid unit. From these results it was concluded that the two chiral units composing the diastereomeric CSPs can show "matched" or "mismatched" effect on the chiral recognition according to their absolute stereochemistry.

• Journal of the Korean Ceramic Society
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• v.27 no.6
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• pp.808-816
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• 1990

The thermal behavior of transformation and characteristics of seeded sample powders prepared by simultaneous $\alpha$-Al2O3 seed addition with water on the Al-sec-butoxide hydrolysis were studied. $\alpha$-Al2O3 seed particles are shown to act as nuclei for transformation of $\theta$-to $\alpha$-Al2O3 and to result in an increase in thetransformation kinetics and lowering of the transformation temperature by as much as 143$^{\circ}C$. Simultaneous seed addition on the hydrolysis resulted in uniform dispersin and creation of nucleation site on seed surface and only 0.1wt% seeding lowered the transformation temperature by as much as 115$^{\circ}C$. For 3wt% seed addition, $\alpha$-Al2O3 single phase was obtained at 95$0^{\circ}C$ for 100 minutes and the specific surface area of products were lowered to 11.9$m^2$/g as compared with that of $\alpha$-Al2O3 powder prepared without seed at 115$0^{\circ}C$ ; 15.1$m^2$/g due to depression of vermicular structure growth.

• Archives of Pharmacal Research
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• v.26 no.9
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• pp.731-734
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• 2003

Five known kaurane type diterpenoids, 16$\alpha$H, 17-isovaleryloxy-ent-kauran-19-oic acid (1), 16$\alpha$-hydroxy-17-isovaleryloxy-ent-kauran-19-oic acid (2), paniculoside-IV (3), 16$\alpha$-hydroxy-ent-kauran-19-oic acid (4), and ent-kaur-16-en-19-oic acid (5) were isolated from the root of Acanthopanax koreanum by repeated column chromatography and reversed phase preparative HPLC. The structures of these compounds were established from physicochemical and spectral data. Among the isolated compounds 16$\alpha$H, 17-isovaleryloxy-ent-kauran-19-oic acid (1) showed potent inhibitory activity ($IC_50$ value, 16.2 $\mu$ M) on TNF-$\alpha$ secretion from HMC-1, a trypsin-stimulated human leukemic mast cell line.

• Textile Coloration and Finishing
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• v.28 no.4
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• pp.231-238
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• 2016

We investigated the evolution of crystal formation as a function of drawing ratio in poly(1,4-diaminobutane-co-adipic acid-co-${\varepsilon}$-caprolactam-co-diethylenetriamine)(nylon 466T) copolymer formed by four monomers, i.e 1,4-diaminobutane, adipic acid, ${\varepsilon}$-caprolactam, diethylenetriamine(DETA), using synchrotron X-ray scattering measurement. In case of pristine(as spun) nylon 466T fiber, it was consisted with unoriented nylon $6{\alpha}$ and unoriented nylon $46{\alpha}$ phases. As increase the drawing ratio, unoriented nylon $6{\alpha}$ was transformed to oriented ${\gamma}$ phase, while unoriented nylon $46{\alpha}$ changed to oriented $46{\alpha}$ phase. The effect of the addition of DETA was not observed in the pristine fibers. However, DETA affected to restrict the formation of crystals at the maximum drawing condition, and as a result it had a role to increase the moisture regain.

• Food Science of Animal Resources
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• v.30 no.5
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• pp.787-794
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• 2010

Calcium plays a role as a signaling molecule in various cellular events. It has been reported that calcium suppresses adipocyte differentiation only in the early phase of adipogenesis. Herein, we demonstrate that treatment of A23187, a mobilizer of intracellular calcium, on day 4 post adipocyte differentiation could still reduce lipid accumulation in differentiating 3T3-L1 cells for 48 h. In addition, luciferase reporter gene and RT-Q-PCR assays demonstrate that A23187 can selectively inhibit transcriptional activities and expression of PPAR$\gamma$ and LXR$\alpha$, suggesting that A23187 may reduce lipid accumulation in the late phase of adipogenesis via downregulation of PPAR$\gamma$ and LXR$\alpha$ expression and transactivation. Moreover, inhibition of HDAC activity by trichostatin A (TSA) partially blocked A23187-mediated downregulation of transcriptional activities of PPAR$\gamma$ and LXR$\alpha$. Together, our data demonstrate that calcium mobilization inhibits expression and transcriptional activities of PPAR$\gamma$ and LXR$\alpha$, resulting in reduced lipid accumulation in differentiating adipocytes, and thus, mobilization of intracellular calcium in adipocytes may serve as a new preventive and therapeutic approach for obesity.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.5
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• pp.110-119
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• 2009

In this study magnetic fields near electric power lines with branch lines which have a arbitrary angle were derived and formulated by dipole antenna theory and could be calculated easily using the formula. It seems that those formula could be applicable to the consideration of magnetic fields during the design of distribution lines with branch lines. As an example those formulated equations on elements of magnetic fields were applied to a model of 3 phase distribution lines with branch lines and calculated by Matlab programs and the results were presented The analyzed results are follows. The resultant magnetic field is dominated by the componant By all over y-axis in the case of the smaller branched angle $\alpha$ and the lower observed point z. In case of ${\alpha}=\frac{\pi}{2}$[rad], the resultant field is affected by the componant Bx. The resultant field is dominated by the componant Bz at the vicinity of the power lines and it shows very large value at the branch line position of y-axis in case of ${\alpha}>\frac{\pi}{2}$.

• Korean Journal of Materials Research
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• v.12 no.4
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• pp.317-323
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• 2002

Effect of V and Sb content on characteristics of ${\beta}\;to\;{\alpha}$ phase transformation in Zr-0.84Sn alloy has been studied using optical microscopy and transmission electron microscopy. As V content increased, the ${\beta}{\to}{\beta}+{\alpha}$ transformation temperature was lowered, thus allowing the width of $\alpha$-lath in air-cooled Zr-0.86Sn-0.40V alloy to be fine. The width of ${\alpha}$-lath in air-cooled Zr-0.84Sn-xSb, however, was rarely changed with Sb content. The ${\beta}\;to\;{\alpha}$ transformed microstructures of water-quenched Zr-0.84Sn, Zr-0.84Sn-0.10V and Zr-0.84Sn-0.19V alloys were mainly slipped martensite. On the other hand, those of wafter-quenched Zr-0.86Sn-0.40V and Zr-0.85Sn-0.05Sb alloys were predominantly twinned martensite. In case of water-quenched Zr-0.85Sn-0.12Sb and Zr-0.84Sn-0.17Sb alloys, basketweave structure was observed. The transition of slipped martensite to twinned martensite in Zr-0.84Sn-xV alloys and the transition of twinned martensite to basketweave structure in Zr-0.84Sn-xSb alloys were due to the decrease of $M_s$ temperature.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.427-431
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• 1995

The influence of Nd and B contents on the magnetic properties and structures of ${\alpha}-Fe$ based Nd-(Fe,Co)-B-Mo-Cu alloys was investigated. $Nd_{4}{(Fe_{0.9}Co_{0.1})}_{92-x}B_{x}Mo_{3}Cu_{1}$ and $Nd_{x}{(Fe_{0.9}Co_{0.1})}_{86-x}B_{10}Mo_{3}Cu_{1}$ amorphous alloys prepared by rapid solidification process were crystallized to form nanocrystalline structure. The increase of B content in $Nd_{4}{(Fe_{0.9}Co_{0.1})}_{92-x}B_{x}Mo_{3}Cu_{1}$ nanocrystalline resulted in the change of stucture of soft phase in the sequence of ${\alpha}-Fe$->${\alpha}-Fe+Fe_{3}B$->$Fe_{3}B$. The coercivitis of the alloys were increased with increasing B content and was 263 kA/m at x=18. On the contrary, the remanence has shown an opposite trends. The increase of Nd content in $Nd_{x}{(Fe_{0.9}Co_{0.1})}_{86-x}B_{10}Mo_{3}Cu_{1}$ nanocrystalline containing ${\alpha}-Fe$ as main phase had no effect on the structure and improved coercivity up to 256 kA/m. However, the remanence was decreased from 1.4 T to 1.15 T according to the increase of Nd content.

• Journal of Korea Foundry Society
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• v.35 no.2
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• pp.36-43
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• 2015

In this study, the influences of aluminum and tin additions (individual and combined) on corrosion behavior of magnesium alloy have been determined. The studied alloys were fabricated by permanent mold casting method to measure the corrosion properties, a potentiodynamic test, hydrogen evolution test and immersion test were carried out in a 3.5% NaCl solution at pH 7.2. From the results of microstructure analysis, the Mg-9Al-1Zn alloy was found to be composed of ${\alpha}$-Mg and rod-like $Mg_{17}Al_{12}$ phase and the Mg-5Sn-5Al-1Zn alloy was found to be composed of ${\alpha}$-Mg, rod-like $Mg_{17}Al_{12}$ and $Mg_2Sn$ phases. In the case of the Mg-9Sn-1Zn alloy, the microstructure was composed of ${\alpha}$-Mg and eutectic $Mg_2Sn$ phase. With Sn addition (individual and combined), the corrosion resistance of the Mg alloys improved.