• Journal of the Korean Chemical Society
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• v.56 no.4
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• pp.416-423
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• 2012

Using time domain reflectometry, the complex dielectric spectra between 10 MHz to 20 GHz has been measured in the whole composition range at 10, 20, 30 and $40^{\circ}C$ for the binary mixtures of ethylene glycol and dimethyl sulfoxide. For all the mixtures, only one dielectric loss peak was observed in this frequency range. The relaxation in these mixtures can be described by a single relaxation time using the Debye model. A systematic variation is observed in dielectric constant (${\varepsilon}_0$) and relaxation time (${\tau}$). The excess permittivity (${\varepsilon}^E$), excess inverse relaxation time $(1/{\tau})^E$, Kirkwood correlation factor (g) and thermodynamic parameters viz. enthalpy of activation (${\Delta}H$) and Gibbs free energy of activation (${\Delta}G$) have been determined, to confirm the formation of hydrogen bonded homogeneous and heterogeneous cooperative domains, the dynamics of solute - solute interaction and the hindrance to molecular rotation in the hydrogen bonded glass forming ethylene glycol - dimethyl sulphoxide system.

• Journal of The Korean Astronomical Society
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• v.43 no.5
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• pp.141-152
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• 2010

UBV I CCD photometry is obtained for the open clusters NGC 4609 and Hogg 15 in Crux. For NGC 4609, CCD data are presented for the first time. From new photometry we derive the reddening, distance modulus and age of each cluster - NGC 4609 : E(B-V ) = $0.37{\pm}0.03$, $V_0-M_V=10.60{\pm}0.08$, log $\tau$= 7.7 $\pm$ 0.1; Hogg 15 : E(B - V ) = 1.13 $\pm$ 0.11, $V_0-M_V$ = 12.50 $\pm$ 0.15, log $\tau$ $\lesssim$ 6.6. The young age of Hogg 15 strongly implies that WR 47 is a member of the cluster. We also determine the mass function of these clusters and obtain a slope $\Gamma$ = -1.2 ($\pm$0.3) for NGC 4609 which is normal and a somewhat shallow slope (${\Gamma}=-0.95{\pm}0.5$) for Hogg 15.

• BMB Reports
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• v.43 no.10
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• pp.704-709
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• 2010

The Swedish mutation (K595N/M596L) of amyloid precursor protein (APP-swe) has been known to increase abnormal cleavage of cellular APP by Beta-secretase (BACE), which causes tau protein hyperphosphorylation and early-onset Alzheimer's disease (AD). Here, we analyzed the effect of APP-swe in global gene expression using deep transcriptome sequencing technique. We found 283 genes were down-regulated and 348 genes were up-regulated in APP-swe expressing H4-swe cells compared to H4 wild-type cells from a total of approximately 74 million reads of 38 base pairs from each transcriptome. Two independent mechanisms such as kinase and phosphatase signaling cascades leading hyperphosphorylation of tau protein were regulated by the expression of APP-swe. Expressions of catalytic subunit as well as several regulatory subunits of protein phosphatases 2A were decreased. In contrast, expressions of tau-phosphorylating glycogen synthase kinase $3\beta$(GSK-3$\beta$), cyclin dependent kinase 5 (CDK5), and cAMP-dependent protein kinase A (PKA) catalytic subunit were increased. Moreover, the expression of AD-related Aquaporin 1 and presenilin 2 expression was regulated by APP-swe. Taken together, we propose that the expression of APP-swe modulates global gene expression directed to AD pathogenesis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.5
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• pp.380-384
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• 2013

In this paper, we have developed a low temperature process to make two type of paste by using $TiO_2$ nanoparticles(P25). The interconnections between substrate and $TiO_2$ films or link between particles of free-binder paste(FP1, FP2, FP3) is very poor. Therefore, the Titanium(IV) isopropoxide was added to the TP paste to improve the interconnection. Electron transport time (${\tau}_t$) and recombination time (${\tau}_r$) are analyzed by IMPS (intensity-modulated photocurrent spectroscopy) and IMVS(Intensity-modulated photovoltage spectroscopy). In the results, ${\tau}_t$ of TP paste based DSSCs (about $4.3{\times}10^{-3}$) is faster than other samples. ${\tau}_r$ is longer from $2.7{\times}10^{-2}$ s of FP2 to $3.0{\times}10^{-2}$ s of TP. A solar conversion efficiency (DSSCs) of TP is 3.54% for an incident solar energy of 100 mW $cm^{-2}$(meanwhile, 2.70% for DSSCs with FP2). The conversion efficiency is increased by 1.3 times.

• Toxicological Research
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• v.29 no.1
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• pp.7-14
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• 2013

Betaine supplementation has been shown to alleviate altered glucose and lipid metabolism in mice fed a high-fat diet or a high-sucrose diet. We investigated the beneficial effects of betaine in diabetic db/db mice. Alleviation of endoplasmic reticulum (ER) and oxidative stress was also examined in the livers and brains of db/db mice fed a betaine-supplemented diet. Male C57BL/KsJ-db/db mice were fed with or without 1% betaine for 5 wk (referred to as the db/db-betaine group and the db/db group, respectively). Lean non-diabetic db/+ mice were used as the control group. Betaine supplementation significantly alleviated hyperinsulinemia in db/db mice. Betaine reduced hepatic expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha, a major transcription factor involved in gluconeogenesis. Lower serum triglyceride concentrations were also observed in the db/db-betaine group compared to the db/db group. Betaine supplementation induced hepatic peroxisome proliferator-activated receptor alpha and carnitine palmitoyltransferase 1a mRNA levels, and reduced acetyl-CoA carboxylase activity. Mice fed a betaine-supplemented diet had increased total glutathione concentrations and catalase activity, and reduced lipid peroxidation levels in the liver. Furthermore, betaine also reduced ER stress in liver and brain. c-Jun N-terminal kinase activity and tau hyperphosphorylation levels were lower in db/db mice fed a betaine-supplemented diet, compared to db/db mice. Our findings suggest that betaine improves hyperlipidemia and tau hyperphosphorylation in db/db mice with insulin resistance by alleviating ER and oxidative stress.

• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.1
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• pp.57-62
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• 1990

This paper deals with the flow caused by a two-dimensional pulsating source, which moves with a constant horizontal speed beneath the free surface. The analysis is based on lincar potential theory including surface tension effects. In the case of subcritical reduced frequencies $\tau<1/4(\tau=U_{\omega}/g$, U=constant speed, $\omega$=circular frequency, g=gravitational acceleration), six wave components arc found. Two of them are largely affected by surface tension, which propagate ahead of the source in the direction of and opposite to the steady translation, respectively. The rest are almost identical with those found by Haskind(1954), i.e. for which the surface tension effect is negligible. For low oscillation frequencies, the resonant frequency still exists at $\tau$ only slightly greater than 1/4. For oscillation frequencies greater than $\nu(={\omega}^2/g)>20$, the surface tension effect is so significant that it disperses generated waves and consequently the singular phenomenon is removed. However, in addition to the gravity breaking, capillary breakings occur when the translation speed coincides with the minimum capillary celerity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.3
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• pp.217-226
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• 2016

In this study, we investigated the antioxidative and cellular protective effects on HaCaT cells and erythrocytes of Moringa oleifera (M. oleifera) leaves extract and its fractions. All experiments were performed with 50% ethanol extract, ethyl acetate fraction and aglycone fraction of M. oleifera leaves. The free radical scavenging activity ($FSC_{50}$) of the extract and fractions of M. oleifera leaves were in the following order: 50% ethanol extract ($77.10{\mu}g/mL$) < ethyl acetate fraction ($20.63{\mu}g/mL$) < aglycone fraction ($17.00{\mu}g/mL$) by using the 1, 1-diphenyl-2-picrylhydrazyl. In $Fe^{3+}-EDTA/H_2O_2$ system using the luminol, reactive oxygen species (ROS) scavenging activities (total antioxidant capacity, $OSC_{50}$) of aglycone fraction ($OSC_{50}=0.63{\mu}g/mL$) was the strongest among all extracts, which was much higher than L-ascorbic acid ($1.50{\mu}g/mL$). In the $^1O_2$-induced cellular damage of erythrocytes, the cellular protective effects of 50% ethanol extract (${\tau}_{50}=46.9min$) and aglycone fraction (${\tau}_{50}=122.1min$) were higher than (+)-${\alpha}$-tocopherol (${\tau}_{50}=37.7min$), known as a lipophilic antioxidant at $10{\mu}g/mL$. After cell damage induced by $400mJ/cm^2$ UVB irradiation, the cellular protective effects of ethyl acetate and aglycone fraction of M. oleifera leaves extract were showed on the concentration from 0.20 to $1.56{\mu}g/mL$. These results suggest that M. oleifera leaves extract and its fractions can function as a natural antioxidant agent in cosmetics on skin exposed to UV radiation by protecting cellular membrane against ROS.

• Journal of the Korean Mathematical Society
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• v.47 no.3
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• pp.495-504
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• 2010

This paper continues a line investigation in [1]. Let A be a K-algebra and M an A/K-bimodule. In [5] Hamaguchi gave a necessary and sufficient condition for gDer(A, M) to be isomorphic to BDer(A, M). The main aim of this paper is to establish similar relationships for generalized ($\sigma$, $\tau$)-derivations.

• Journal of the Chungcheong Mathematical Society
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• v.24 no.2
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• pp.239-245
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• 2011

In this paper, we will study the tension field of the function related to a Riemannain submersion ${\pi}\;:\;N{\rightarrow}M$ with totally geodesic fibres. In case that the Riemannain submersion ${\pi}\;:\;N{\rightarrow}M$ particularly has a smooth map $f\;:\;M{\rightarrow}N$ which happens to be a section, we will show that tension field ${\tau}(f)$ of the energy functional can be decomposed into the horizontal and vertical parts.

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.209-218
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• 1996

Acetylcholine (ACh) activates the inwardly rectifying muscarinic $K^{+}$ channel in rat atrial cells via pertussis toxin (PTX)-sensitive G-protein ($G_k$) coupled with the muscarinic receptor (mAChR). Although this $K^{+}\;(K_{ACh})$ channel function has reported to be modulated by the phosphorylation process, a kinase and phosphatase involved in these processes are still unclear. Since either PKA or PKC was not effective on this ATP-modulation, the present study examined the possible involvement of the protein tyrosine kinase (PTK) and protein tyrosine phosphatase (PTP) in the function of the $K_{ACh}$ Channel. In the inside-out (I/O) patch preparation excised from the adult rat atrial cell, when activated by 10 ${\mu}M$ ACh in the pipette and 100 ${\mu}M$ GTP in the bath, the mean open time (${\tau}_{o}$) and the channel activity ($K_{ACh}$) was 1.13 ms (n=5) and 0.19 (n=6), respectively. Following the application of 1 mM ATP into the bath, ${\tau}_{o}$ increased by 34% (1.54 ms, n=5) and $K_{ACh}$ by 66% (0.28, n=6). Channel function elevated by ATP was lasted after washout of ATP. However, this ATP-induced increase in the $K_{ACh}$ channel function did not occur in pretreated cells with genistein ($50{\sim}100 {\mu}M$), a selective PTK inhibitor, but occurred in pretreated cells with equimolar daidzein, a negative control of the genistein. On the contrary, PTP which acts on tyrosine residue conversely reversed both ATP-induced increased ${\tau}_{o}$ by 32% (1.20 ms, n=3) and $K_{ACh}$ by 41% (0.15, n=3), respectively. Taken together, these results suggest that $K_{ACh}$ channel may, at least partly, be regulated by the tyrosyl phosphorylation, although it is unclear where this process exerts on the muscarinic signal transduction pathway comprising the mAChR-$G_{k}$-the $K_{ACh}$ channel.