• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.11
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• pp.730-735
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• 2014

In this study, the temperature characteristics of electrostatic capacity and dielectric loss for the sample of Teflon film which is degradated at the $120^{\circ}C{\sim}200^{\circ}C$ temperature range in the oven for 10 hours has been measured in through the applied frequency range of 0.1 kHz~4,800 kHz at temperature of $50^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $170^{\circ}C$. Also, in the same conditions, the frequency characteristics of electrostatic capacity and dielectric loss for the sample of Teflon film has been measured in through the applied temperature range of $30^{\circ}C{\sim}70^{\circ}C$ on setting frequency of 0.1 kHz, 1 kHz, 10 kHz, 100 kHz. The results of this study are as follows. When the frequency range of 0.1 kHz~4,800 kHz applied to the sample of Teflon film, the electrostatic capacity has been measured at the temperature of $50^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $170^{\circ}C$. Through this measurement, it found that the electrostatic capacity decreased with increasing temperature. Regarding this result, may be it is because the electromagnetic coupling is degraded by thermal degradation. When the sample of Teflon film heated at $280^{\circ}C$ for 10 hours in oven, the dielectric loss has changed from unstable status to stabilizing status with increasing the degradation temperature in the $120^{\circ}C$, $160^{\circ}C$, $200^{\circ}C$ range. In this measurement, the two spectrums of dielectric loss appeared. It considers that this spectrum of dielectric loss appeared in 300 Hz is caused by the molecular motion of the C-F or OH group. Through this study, It found that the electrostatic capacity decreased with increasing frequency and temperature, and there is no change in dielectric loss, although the frequency increases.

• BMB Reports
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• v.40 no.4
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• pp.525-531
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• 2007

As a $\beta_2$-adrenergic agonist, clenbuterol decreases body fat, but the molecular mechanism underlying this process is unclear. In the present study, we treated 293T and L-02 cells with clenbuterol and found that clenbuterol downregulates SREBP-1c expression and upregulates CREB1 expression. Considering SREBP-1c has the function of regulating the transcription of several lipogenic enzymes, we considered that the downregulation of SREBP-1c is responsible for body fat reduction by clenbuterol. Many previous studies have found that clenbuterol markedly increases intracellular cAMP levels, therefore, we also investigated whether CREB1 is involved in this process. The data from our experiments indicate that CREB1 overexpression inhibits SREBP-1c transcription, and that this action is antagonized by CREB2, a competitive inhibitor of CREB1. Furthermore, since PPARs are able to repress SREBP-1c transcription, we investigated whether clenbuterol and CREB1 function via a pathway involving PPAR activation. However, our results showed that clenbuterol or CREB1 overexpression suppressed PPARs transcription in 293T and L-02 cells, which suggested that they impair SREBP-1c expression in other ways.

• Journal of the Korean Chemical Society
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• v.7 no.4
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• pp.257-263
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• 1963

The crystal structure of nicotinic acid hydrochloride has been determined by two-dimensional x-ray method. The unit cell is monoclinic with a = 7.21 ${\AA}$, b = 6.69 ${\AA}$, c = 7.54 ${\AA}$, ${\beta}=100^{\circ}$, space group $C{\frac{2}{2}}-P2_1$, and contains two formula units. Weissenberg diagrams have been taken along the a, b and c axes with Cu K${\alpha}$ radiation and the positions of the atoms have been fixed by means of two dimensional Patterson syntheses, a Fourier projection along the b-axis and trial and error method. The bond lengths are: pyridine ring C-C = 1.38, 1.39 ${\AA}$, C-N = 1.34, 1.36 ${\AA}$, carboxyl group $C_4-C_6$ = 1.46 ${\AA}$, $C_6-O_1$ = l.33 ${\AA}$, $C_6-O_2$ = 1.19 ${\AA}$. The ring nitrogen atom may be regarded as forming bifurcated hydrogen bond with an oxygen atom $O_2$ of one neighbouring molecule and with a neighbouring chlorine atom, being linked by forming a hydrogen bond with an other oxygen atom $O_1$ of above mentioned neighbouring molecule, in such a way that chains parallel to the c-axis are formed.

• Korean Journal of Crystallography
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• v.3 no.1
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• pp.31-36
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• 1992

6, 9-Difluoro-11, 21-dihydroxyl-16, 17-[(1methylehtylidene)bis(oxy)]-pregna-1, 4-diene-3, 20-dione (fluorocinolone acetonide) , C24H3OF106, trigonal, R3 (defined as a hexagonal lattice), a =b = 17.896 k, c: 18.365 k, V=5094.3 A', Z=9, 1 (MoK a) =0.7107 A, D=1.31 g/cm3, D.: 1.328 g/cm3 T=298 K, final R=0.050 for 1101 unique observed reflections. The molecule has conformational features in common with other corticosteroids. Three molecules related by 3-fold symmetry are involved in hydrogen bonding, forming a layer of molecules perpendicular to the c-axis.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3385-3390
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• 2010

$Li^+$ ion complex of azacrown ether with restricted motion of freedom and pseudo-bilateral symmetry was studied by infrared spectroscopy, which has shown simplified and broadened vibrational features. The C=O and N-H stretching bands, in particular, shows anomalous broadening nearly ${\sim}50\;cm^{-1}$. The density functional calculation at the level of BP86/6-31+$G^{**}$ shows that $Li^+$ ion is trapped and rather free to move around inside the cavity, as much as about $0.70\;{\AA}$. Through the relocation of $Li^+$ ion inside the cavity, the conformational changes would occur rapidly in its symmetry $C_1\;{\rightleftarrows}\;C_2\;{\rightleftarrows}\;C_1$$. The potential barrier was obtained to be merely ~2.2 kJ/mol for $C_1\;{\rightarrow}\;C_2$. During this conformational alteration, the amide backbone twists concurrently its dihedral angle side to side about up to ${\pm}3$ degree. Selected vibrational modes were interpreted in terms of the force constant variations of local symmetry coordinates between conformations in the framework of $C_1\;{\rightleftarrows}\;C_2\;{\rightleftarrows}\;C_1$.

• Korean Journal of Crystallography
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• v.15 no.1
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• pp.24-28
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• 2004

The structure of $C_{12}H_{15}N_3O_3$ has been determined by X-ray diffraction methods. The crystal system is monoclinic, space group $P2_1/c$, unit cell constants, a = 12.9955(9) ${\AA}$, b = 7.7137(5) ${\AA}$, c = 13.4699(11) ${\AA}$, ${\beta}$ = 107.86(1)$^{\circ}$, V = 1285.2(1) ${\AA}^3$, T = 296 K, Z = 4, $D_c$ = 1.350 $Mgm^{-3}$. The intensity data were collected on an Enraf-Nonius CAD-4 Diffractometer with graphite monochromated Mo $K{\alpha}$ radiation (${\lambda}$ = 1.71073 ${\AA}$). The molecular structure was solved by direct methods and refined by full-matrix least squares to a final R = 4.19% for 1644 unique observed $F_0\;>\;4{\sigma}(F_0)$ reflections 193 parameters.

• Journal of Life Science
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• v.26 no.9
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• pp.1007-1014
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• 2016

A highly efficient, rapid, and reliable multiplex polymerase chain reaction based method for distinguishing ten species of genus Cynoglossus (C. senegalensis, C. abbreviates, C. macrolepidotus, C. arel, C. semilaevis, C. interruptus, C. joyneri, C. lingua, C. robustus, and C. monodi) is described. The species-specific primer sets were designed base on the cytochrome oxidase subunit I gene (1,500 bp). The optimal PCR conditions and primers were selected for ten of Cynoglossus species to determine target base sequences using single PCR. Multiplex PCR using the ten pairs of primers either specifically amplified a DNA fragment of a unique size or failed, depending on each species DNA. The length of amplification fragment of 208 bp for C. senegalensis, 322 bp for C. abbreviates, 493 bp for C. macrolepidotus, 754 bp for C. arel, 874 bp for C. semilaevis, 952 bp for C. interruptus, 1,084 bp for C. joyneri, 1,198 bp for C. lingua, 1,307 bp for C. robustus, and 1,483 bp for C. monodi with the species-specific primers, visualized by agarose gel electrophoresis, allowed perfectly distinction of the Cynoglossus species. The multiplex PCR assay can be easily performed on multiple samples and attain final results in less than 6 hours. This technique should be a useful addition to the molecular typing tools for the tentative identification of Cynoglossus species.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.1
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• pp.18-26
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• 1997

$\beta-SiC $powder with or without the addition of 1 wt% of $\alpha-SiC$ particles (seeds) was pressureless-sintered at $1950^{\circ}C$ for 0.5, 2 and 4 h using $Y_3Al_5O_{12}$ (yttrium aluminum garnet, YAG) as a sintering aid. The introduction of $\alpha-SiC$ seeds into $\beta-SiC$ accelerated :he grain growth of elongated large grains during sintering, resulting in the coarser microstructure. The fracture toughnesses of materials with $\alpha$-SiC seeds and without $\alpha-SiC$ seeds sintered for 4 h were 7.5 and 6.1 $MPa\cdot \textrm m^{1/2}$, respectively. Higher fracture toughness of the material with seeds was due to the enhanced bridging by elongated grains, resulting from coarser microstructure.

• Food Science and Preservation
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• v.15 no.1
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• pp.1-8
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• 2008

Quality attributes of fresh-cut pak-choi (Brassica campestris var. chinensis) as affected by hydrocooling and packing were investigated in terms of weight loss, respiration, vitamin C content, total chlorophyll content, microbial load and sensory properties during storage at 4 and $10^{\circ}C$. Fresh pak-choi was trimmed and washed with cold water $(1^{\circ}C)$ as well as tap water $(6^{\circ}C)$ for 30 sec 3 times and then packaged in PP (polypropylene) film bag and PETE (polyethylene terephthalate) bay, and stored for 9 days at 4 and $10^{\circ}C$. Weight loss was decreased by washing and packing generally. Respiration rate was increased slowly over the storage at $4^{\circ}C$. Vitamin C content and total chlorophyll contents of pak-choi packaged within PETE bay decreased gradually during storage. Hydrocooling and packing within PETE bay treatments resulted in approximately 1-2 log CFU/g reduction of microbial load.

• Plant Journal
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• v.10 no.2
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• pp.48-59
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• 2014

Coupons which have same figure as weld joint of the forged steel valves and 1 inch nominal weld thickness were manufactured using ASTM A182 F92 material. After welding with GTAW method, the welded specimens have been post-weld heat treated at $705^{\circ}C$, $735^{\circ}C$, $750^{\circ}C$, $765^{\circ}C$, $795^{\circ}C$ and $825^{\circ}C$ for 1 hour per 1 inch nominal weld thickness each (Group 1) to evaluate characteristics of welds based on various holding temperature. Indeed, 3 welded specimens were post-weld heat treated for 30 minutes, 1 hour and 2 hour (Group 2) at $735^{\circ}C$ to evaluate characteristics of welds based on various holding time. Hardness values were measured at the weld metal, heat affected zone and base metal to observe hardness change depending on the condition. As a result of the evaluation, appropriate holding temperature for PWHT is proved as $750^{\circ}C$ and $765^{\circ}C$ for 1hour per 1 inch nominal weld thickness. Indeed, holding for 1 hour per 1 inch nominal weld thickness was insufficient for PWHT effect when the holding temperature was at $735^{\circ}C$. The microstructure of post-weld heat treated weld metal was determined as tempered-martensite structure.