• 한국식품영양학회지
• /
• 제16권4호
• /
• pp.321-327
• /
• 2003

The reaction rates of 4-ethyl pyridine with p-methyl benzylbromide have been measured by conductometry in acetonitrile, and the rate constants of these reactions are determined in accordance with various temperatures (20, 25, 30$^{\circ}C$) and pressures (1, 200, 500, 1000 bar). The rate constants increased with the higher pressure and temperature. The activation energies and activation parameter values of these reactions are calculated by determination of the rate constants the same. The activation volume, activation compressibility coefficient and the activation entropy are all negative. The result of kinetic studies for the pressure show that this reaction proceeds in typical bimolecular nucleophilic substitution reaction.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2011년도 제37회 추계학술대회논문집
• /
• pp.922-925
• /
• 2011

Smoothed Particle Hydrodynamics (SPH) is a Lagrangian method widely used for the modeling fluid flows. Simulations of explosions require, besides the hydrodynamic equations, a realistic equation of state, an energy source term, and a set of chemical kinetic equations to follow the composition changes of the gas during the explosion. The performance of the hydrodynamic equations is investigated in the framework of the Sedov-Taylor blast-wave. The implementation of chemical kinetic equations and equation of state is studied with 1D detonation of TNT slab. Our results are compared to those from analytical and experimental studies.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권7호
• /
• pp.4229-4233
• /
• 2013

Abraxane (nab-paclitaxel) is a member of the group of nano chemotherapeutics. It is approved for metastatic breast cancer and non small cell lung cancer. Trials for several cancer types including gynecological cancers, head and neck, and prostatic cancer are being studied. In this study, the antiproliferative and apoptotic effect of abraxane was evaluated on HeLa cell line originated from human cervix carcinoma. Three different doses ($D_1$=10 nM, $D_2$=50 nM, $D_3$=100 nM) were administered to HeLa cells for 24, 48 and 72 h. The 50 nM dose of abraxane decreased DNA synthesis from 4.62-0.08%, mitosis from 3.36-1.89% and increased apoptosis from 10.6-30% at 72 h. Additionally, tripolar metaphase plates were seen in mitosis preparations. In this study, abraxane effected cell kinetic parameters significantly. This results are consistent with other studies in the literature.

• 한국수소및신에너지학회논문집
• /
• 제12권3호
• /
• pp.191-199
• /
• 2001

In this paper molecular dynamics simulations have been carried out to investigate energy and momentum transfer of hydrogen ions impacted on the Ni (100) surface with $45^{\circ}$ and $90^{\circ}$ incident angles. The initial kinetic energies of the hydrogen ion were ranged from 100 eV to 1,600 eV to study the layer-by-layer energy variation as a dependence of incident energies and angles. At low incident energies, the scattering energy transfer is dominated by the normal motion of surface layers due to thermal vibrations and multiple collision effects. For higher incident energies, the scattering energy transfer in a normal direction is greater than that in a parallel direction. In the case of penetration, the amount of transferred energies do not affect much on Ni layers at low incident energy. It was found channeling effects through Ni layers with increasing incident energies.

• Bulletin of the Korean Chemical Society
• /
• 제27권2호
• /
• pp.255-265
• /
• 2006

The oxidation of hydrazobenzene by molecular oxygen in the polar solvent methanol is catalysed by a Schiff's base complex Co(3MeOsalen) which is a synthetic oxygen carrier. The products are trans-azobenzene and water. The rate of the reaction has been studied spectrophotometrically and the rate law established. A mechanism involving a ternary complex of catalyst, hydrazobenzene and molecular oxygen has been proposed. The kinetic studies show that a ternary complex $CoL{\cdot}H_2AB{\cdot}O_2$ is involved in the rate determining step. The reactions are summarised in a catalytic cycle. The kinetic data suggest that a ternary complex involving Co(3MeOsalen), triphenyl-phosphine and molecular oxygen is catalytically acive species but at higher triphenylphosphine concentrations the catalyst becomes inactive. The destruction of the catalytic activity could be due to the catalyst becoming coordinated with triphenyl phosphine at both z axis sites of the complex e.g. Co (3MeOsalen)$(PPh_3)_2$.

• Bulletin of the Korean Chemical Society
• /
• 제24권1호
• /
• pp.91-94
• /
• 2003

Kinetic studies of the reaction of O-methyl-S-phenylthiocarbonates with benzylamines in methanol at 45.0 ℃ have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterionic tetrahedral intermediate, $T^{\pm}$, with a hydrogen-bonded four-center type transition state (TS). These mechanistic conclusions are drawn based on (ⅰ) the large magnitude of ${\rho}_X\;and\;{\rho}_Z$, (ⅱ) the normal kinetic isotope effects $(k_H/k_D\;>\;1.0)$ involving deuterated benzylamine nucleophiles, (ⅲ) the positive sign of ${\rho}_{XZ}$ and the larger magnitude of ${\rho}_{XZ}$ than that for normal $S_N2$ processes, and lastly (ⅳ) adherence to the reactivity-selectivity principle (RSP) in all cases.

• 천문학회보
• /
• 제38권1호
• /
• pp.47.1-47.1
• /
• 2013

Supersonic turbulence is believed to decay rapidly within a flow crossing time irrespective of the degree of magnetization. However, this consensus of decaying magnetohydrodynamic (MHD) turbulence relies on local isothermal simulations, which are unable to investigate the role of global magnetic fields and structures. Utilizing three-dimensional MHD simulations including interstellar cooling and heating, we investigate decaying MHD turbulence within cold neutral medium sheets embedded in warm neutral medium. Early evolution is consistent with previous studies characterized rapid decay of turbulence with the decaying time shorter than a flow crossing time and power-law temporal decay of turbulent kinetic energy with slope of -1. If initial magnetic fields are strong and perpendicular to the sheet, however long term evolutions of kinetic energy shows that a significant amount of turbulent energy still remains even after ten flow crossing times, and decaying rate is reduced as field strengths increase. We analyse power spectra of remaining turbulence to show that incompressible, in-plane motions dominate.

• Bulletin of the Korean Chemical Society
• /
• 제35권4호
• /
• pp.1016-1022
• /
• 2014

The kinetic studies on the reactions of O-methyl N,N-diisopropylamino phosphonochloridothioate with X-anilines and X-pyridines have been carried out in acetonitrile. The free energy relationship with X in the anilines exhibits biphasic concave upwards with a break region between X = (H and 4-F), giving unusual negative ${\beta}_X$ and positive ${\rho}_X$ values with weakly basic anilines. The unusual phenomenon is rationalized by isokinetic relationship. A stepwise mechanism with a rate-limiting leaving group departure from the intermediate is proposed based on the selectivity parameter and variation trend of the deuterium kinetic isotope effects with X. The free energy relationship with X in the pyridines exhibits biphasic concave upwards with a break point at X = 3-MeO. A concerted mechanism is proposed based on relatively small ${\beta}_X$ value, and frontside and backside nucleophilic attack are proposed with strongly and weakly basic pyridines, respectively.

• Archives of Pharmacal Research
• /
• 제9권2호
• /
• pp.81-86
• /
• 1986

The effect of imperatorin on hepatic microsomal mixed function oxidases (MF0) was investigated. On acute treatment, imperatorin (30 mg/kg, i.p) caused a significant reduction in activities of hepatic aminopyrine N-demethylase, hexobarbital hydroxylase and aniline hydroxylase as well as cytochrome p0450 content in rats and mice. Kinetic studies on rat liver enzymes revealed that imperatorin appeared to be a competitive inhibitor of aminopyrine N-demethylase (Ki,0.007 mM), whereas a non-competitive inhibitor of hexobarbital hydroxylase (Ki, 0.0148 mM). Imperatorin also inhibited non-competitively aniline metabolism (Ki 0.2 mM). Imperatorin binds to phenobarbital-induced cytochrome p-450 to give a typical type 1 binding sepctrum (max. 388nm, min 422 nm). Multiple administrations of imperatorin (30 mg/kg. i. p. daily for 7 days) to mice shortended markedly the duration of hexobarbital narcosis and increased activities of hepatic aminopyrine N-demethylase and hexobarbital hydroxylase and the level of cytochrome p-450 where as aniline hydroxylase activity was unaffected.

• Bulletin of the Korean Chemical Society
• /
• 제17권8호
• /
• pp.712-715
• /
• 1996

Kinetic studies are carried out on the reactions of N-methyl-N-phenylcarbamoyl chlorides with benzylamines in acetonitrile. The selectivity parameters, ρX (=-0.6~-0.8), ρY (=1.0-1.1), and ρXY (=-0.14), suggest that the reaction proceeds by an SN2 mechanism. Kinetic isotope effects, kH/kD, involving deuterated nucleophiles (XC6H4CH2ND2) are all inverse type (<1.0), and the trends of changes in the magnitude are consistent with those expected for the observed negative sign of ρXY(=∂ρX/∂σY = ∂ρY/∂σX < 0). The relatively low activation enthalpies also support the proposed mechanism.