• The Korean Journal of Physiology and Pharmacology
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• v.26 no.3
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• pp.175-182
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• 2022

Translocation of azurophil granules is pivotal for bactericidal activity of neutrophils, the first-line defense cells against pathogens. Previously, we reported that lysophosphatidylcholine (LPC), an endogenous lipid, enhances bactericidal activity of human neutrophils via increasing translocation of azurophil granules. However, the precise mechanism of LPC-induced azurophil granule translocation was not fully understood. Treatment of neutrophil with LPC significantly increased CD63 (an azurophil granule marker) surface expression. Interestingly, cytochalasin B, an inhibitor of action polymerization, blocked LPC-induced CD63 surface expression. LPC increased F-actin polymerization. LPC-induced CD63 surface expression was inhibited by both a Rho specific inhibitor, Tat-C3 exoenzyme, and a Rho kinase (ROCK) inhibitor, Y27632 which also inhibited LPC-induced F-actin polymerization. LPC induced Rho-GTP activation. NSC23766, a Rac inhibitor, however, did not affect LPC-induced CD63 surface expression. Theses results suggest a novel regulatory mechanism for azurophil granule translocation where LPC induces translocation of azurophil granules via Rho/ROCK/F-actin polymerization pathway.

• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.23.2-23.2
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• 2007

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• Korea-Australia Rheology Journal
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• v.14 no.3
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• pp.129-138
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• 2002

A cationic surfactant, cetyltrimethylammonium $\rho$-toluenesufonate (CTA$\rho$TS), forms long threadlike micelles in aqueous solution. The threadlike micelles make concentrated entanglement networks, so that the solution shows pronounced viscoelastic behavior as concentrated polymer systems do. However, a mechanism for a process responsible for the longest relaxation time of the threadlike micellar system is different from that of semi-dilute to concentrated polymer systems. The threadlike micellar system exhibits unique viscoelasticity described by a Maxwell model. The longest relaxation time of the threadlike micellar system is not a function of the concentration of CTA$\rho$TS, but changes with that of $\rho$-toluenesufonate ($\rho$$TS^{-}$) ions in the bulk aqueous phase supplied by adding sodium $\rho$-toluenesulfonate (NapTS). The rates of molecular motions in the threadlike micelles are not influenced by the concentration of $\rho$$TS^{-}$ anions, therefore, molecular motions in the threadlike micelles (micro-dynamics) are independent of the longest relaxation mechanism (macro-dynamics). A nonionic surfactant, oleyldimethylamineoxide (ODAO), forms long threadlike micelles in aqueous solution without any additives. The aqueous threadlike micellar system of ODAO also shows Maxwell type viscoelastic behavior. However, the relaxation mechanism for the longest relaxation process in the system should be different from that in the threadlike micellar systems of CTA$\rho$TS, since the system of ODAO does not contain additive anions. Because increase in the average degree of protonation of head groups of ODAO molecules in micelles due to adding hydrogen bromide causes the relaxation time remarkably longer, changes in micro-structure and micro-dynamics in the threadlike micelle are closely related to macro-dynamics in contrast with the threadlike micellar system of CTA$\rho$TS.

• Molecules and Cells
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• v.26 no.4
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• pp.396-403
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• 2008

The first ORF of the ARV S1133 S1 segment encodes the nonstructural protein p10, which is responsible for the induction of cell syncytium formation. However, p10-dependent signaling during syncytium formation is fully unknown. Here, we show that dominant negative RhoA, Rho inhibitor C3 exoenzyme, ROCK/Rho-kinase inhibitor Y-27632 and Rac1 inhibitor NSC23766 inhibit p10-mediated cell fusion. p10 over-expression is concomitant with activation and membrane translocation of RhoA and Rac1, but not cdc42. RhoA and Rac1 downstream events, including JNK phosphorylation and transcription factor AP-1 and $NF-{\kappa}B$ activation, as well as MLC expression and phosphorylation are simultaneously activated by p10. p10 point mutant T13M possessed 20% fusion-inducing ability and four p10 fusion-deficient mutants V15M, V19M, C21S and L32A reduced or lost their ability to activate RhoA and Rac1 signaling. We conclude that p10-mediated syncytium formation proceeds by utilizing RhoA and Rac1-dependent signaling.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.2
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• pp.95-101
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• 2013

This paper presents the comparison of the earth resistivity obtained from the measurements made with the three-electrode and four-electrode fall-of-potential techniques. The ${\rho}-a$ curve obtained from Wenner four-electrode method in undisturbed earth is in good agreement with the ${\rho}-l$ curve obtained from the three-electrode method based on the fall-of- potential method. However, The ${\rho}-a$ curve in disturbed earth with moisture and freezing is significantly different with the ${\rho}-l$ curve. The ${\rho}-a$ curve is considerably sensitive to the freezing and the moisture present in the earth surface compared to the ${\rho}-l$ curve. Thus to determine the actual earth resistivity, it is necessary to take into account the earth surface conditions when measuring the earth resistivity.

• Journal of the Korean Chemical Society
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• v.32 no.5
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• pp.416-421
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• 1988

Kinetic studies for the nucleophilic substitution reactions of benzyl halides(para-substituted benzyl bromides and benzyliodide) with substituted pyridines in MeOH-MeCN mixtures have been carried out in order to elucidate the reaction mechanism. Cross interaction coefficient, ${\rho}_{XY}$ values suggested that the reactions between benzylhalides and substituted pyridines exhibit an dissocitive $S_N$2 mechanism. Hammett (${\rho}_X$, ${\rho}_Y$), Br${\o}$nsted ${\beta}_N$ and solvatochromic correlation coefficient a, s, a/s values were illustrated. Kinetic results were compared between potential energy surface model and quantum mechanical model. The quantum mechanical approach showed to be consistent with kinetic results.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3805-3809
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• 2012

Results for molecular dynamics simulation method of small liquid drops of argon (N = 1200-14400 molecules) at 94.4 K through a Lennard-Jones intermolecular potential are presented in this paper as a preliminary study of drop systems. We have calculated the density profiles ${\rho}(r)$, and from which the liquid and gas densities ${\rho}_l$ and ${\rho}_g$, the position of the Gibbs' dividing surface $R_o$, the thickness of the interface d, and the radius of equimolar surface $R_e$ can be obtained. Next we have calculated the normal and transverse pressure tensor ${\rho}_N(r)$ and ${\rho}_T(r)$ using Irving-Kirkwood method, and from which the liquid and gas pressures ${\rho}_l$ and ${\rho}_g$, the surface tension ${\gamma}_s$, the surface of tension $R_s$, and Tolman's length ${\delta}$ can be obtained. The variation of these properties with N is applied for the validity of Laplace's equation for the pressure change and Tolman's equation for the effect of curvature on surface tension through two routes, thermodynamic and mechanical.

• Molecules and Cells
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• v.27 no.2
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• pp.191-198
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• 2009

The present study was undertaken to determine whether treatment with genistein, the plant-derived estrogen-like compound influences agonist-induced vascular smooth muscle contraction and, if so, to investigate related mechanisms. The measurement of isometric contractions using a computerized data acquisition system was combined with molecular experiments. Genistein completely inhibited KCl-, phorbol ester-, phenylephrine-, fluoride- and thromboxane $A_2$-induced contractions. An inactive analogue, daidzein, completely inhibited only fluoride-induced contraction regardless of endothelial function, suggesting some difference between the mechanisms of RhoA/Rho-kinase activators such as fluoride and thromboxane $A_2$. Furthermore, genistein and daidzein each significantly decreased phosphorylation of MYPT1 at Thr855 had been induced by a thromboxane $A_2$ mimetic. Interestingly, iberiotoxin, a blocker of large-conductance calcium-activated potassium channels, did not inhibit the relaxation response to genistein or daidzein in denuded aortic rings precontracted with fluoride. In conclusion, genistein or daidzein elicit similar relaxing responses in fluoride-induced contractions, regardless of tyrosine kinase inhibition or endothelial function, and the relaxation caused by genistein or daidzein was not antagonized by large conductance $K_{Ca}$-channel inhibitors in the denuded muscle. This suggests that the RhoA/Rho-kinase pathway rather than $K^+$- channels are involved in the genistein-induced vasodilation. In addition, based on molecular and physiological results, only one vasoconstrictor fluoride seems to be a full RhoA/Rho-kinase activator; the others are partial activators.

• Journal of the Korea Society of Computer and Information
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• v.20 no.8
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• pp.29-33
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• 2015

This paper proposes a discrete logarithm algorithm that remarkably reduces the execution time of Pollard's Rho algorithm. Pollard's Rho algorithm computes congruence or collision of ${\alpha}^a{\beta}^b{\equiv}{\alpha}^A{\beta}^B$ (modp) from the initial value a = b = 0, only to derive ${\gamma}$ from $(a+b{\gamma})=(A+B{\gamma})$, ${\gamma}(B-b)=(a-A)$. The basic Pollard's Rho algorithm computes $x_i=(x_{i-1})^2,{\alpha}x_{i-1},{\beta}x_{i-1}$ given ${\alpha}^a{\beta}^b{\equiv}x$(modp), and the general algorithm computes $x_i=(x_{i-1})^2$, $Mx_{i-1}$, $Nx_{i-1}$ for randomly selected $M={\alpha}^m$, $N={\beta}^n$. This paper proposes 4-model Pollard Rho algorithm that seeks ${\beta}_{\gamma}={\alpha}^{\gamma},{\beta}_{\gamma}={\alpha}^{(p-1)/2+{\gamma}}$, and ${\beta}_{{\gamma}^{-1}}={\alpha}^{(p-1)-{\gamma}}$) from $m=n={\lceil}{\sqrt{n}{\rceil}$, (a,b) = (0,0), (1,1). The proposed algorithm has proven to improve the performance of the (0,0)-basic Pollard's Rho algorithm by 71.70%.

• YAKHAK HOEJI
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• v.50 no.4
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• pp.293-299
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• 2006

The aim of present study was to investigate the possible influence of Rho-kinase inhibition on the plant-derived estrogen-like compounds-induced arterial relaxation. Agonist- or depolarization-induced vascular smooth muscle contractions involve the activation of Rho-kinase pathway. However there are no reports addressing the question whether this pathway is involved in genistein-or daidzein-induced vascular relaxation in rat aortae precontracted with phenylephrine or thromboxane $A_2$ mimetic U-46619. We hypothesized that Rho-kinase inhibition plays a role in vascular relaxation evoked by genistein or daidzein in rat aortae. Endothelium-intact and denuded arterial rings from male Sprague-Dawley rats were used and isometric contractions were recorded using a computerized data acquisition system. Genistein concentration-dependently inhibited phenylephrine or thromboxane $A_2-induced$ contraction regardless of endothelial function. Surprisingly, in the agonists-induced contraction, similar results were also observed in aortae treated with daidzein, the inactive congener for protein tyrosine kinase inhibition, suggesting that Rho-kinase might act upstream of tyrosine kinases in phenylephrine-induced contraction. In conclusion, in the agonists-precontracted rat aortae, genistein and daidzein showed similar relaxant response regardless of tyrosine kinase inhibition or endothelial function.