• Journal of the Korean Chemical Society
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• v.17 no.2
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• pp.95-104
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• 1973

Ground electronic structures and SNreactivities of a series of alkylchlorides (methyl,ethyl, iso-propyl, trans n-butyl, sec-butyl, tert-butylchloride) have been studied using approximate $({\sigma}-MO)$ method, such as EHT and CNDO/2. It was found that CNDO/2 gives better results for the systems such as alkylchlorides whose structural differences are not remarkable, in comparison with EHT method. According to CNDO/2 results, calculated dipole moments for alkylchlorides are slightly higher than observed values, showing the order of primary < secondary < tertiary alkylchlorides. It was also found that highest occupied(HO) MO's are completely or nearly degenerate, and show relatively weak $\pi$-antibonding nature between$\alpha$-carbon and Cl atoms. Furthermore, the electrons in this MO are largely confined to Cl atom, and hence these behaves as likely as p-lone pair electrons of Cl atom. On the contrary, lowest unoccupied (LU) MO's show strong $\sigma$-antibonding nature between $\alpha$-carbon and Cl atoms whose electron clouds are directed along the C-Cl axis. It has been discussed that the$S_N2$ reactivities of alkylchlorides may largely be controlled by ${\sigma}^{\ast}$ LUMO, and the antibonding strength between $\alpha$-carbon and Cl atoms in this MO may become the measure of $S_N2$reactivity. The relationship between $S_N2$reactivity and C-Cl bond polarizability has also been discussed. It has been suggested that the unique structure factors determining $S_N1$reactivities may be $\pi$-antibonding strength between $\alpha$-carbon and Cl atoms in HOMO and C-Cl bond strength in ground state.

• Herbal Formula Science
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• v.12 no.1
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• pp.209-223
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• 2004

Objective: This study was conducted to investigate the effects of Coptidis Rhizoma on the plasma IL-6 and $TNF-{\alpha}$ level in mice by intracerebroventricular(I.C.V.) injection of Lipopolysaccharide (LPS). Method: 6 mice were assigned to each of the Normal group, the Control group, and the individual Experimental groups. In the Normal group only saline was administered intragastrically, and in the Control group LPS was injected intracerebroventricularly 1 hr after intragastric administration of saline. In the Experimental groups Coptidis Rhizoma(0.5g/kg, 1.0g/kg, 3.0g/kg) was administered intragastrically to mice 1 hr prior to LPS (100ng/mouse) I.C.V. Injection. To measure the plasma IL-6 and $TNF-{\alpha}$ level of mice, their blood samples were collected from retro-orbital venous plexus, immediately centrifuged at $4^{\circ}C$, and plasma was removed and stored frozen at $-83^{\circ}C$ for later determination of plasma IL-6 and $TNF-{\alpha}$. Result: 1. LPS I.C.V. Injection increased plasma IL-6 level significantly in a dose-dependent manner compared with Normal group. (P<0.01) The plasma IL-6 concentration reached a significant maximal level about 1 hr after LPS(100ng/mouse) I.C.V. Injection.(P<0.001) 2. Both the 0.5g/kg(Sample A) and 1.0g/kg(Sample B) groups to which Coptidis Rhizoma was administered intragastrically 1 hr prior to LPS(100ng/mouse) I.C.V. Injection showed insignificant lower plama IL-6 level in 1 hr than Control group(P>0.05), and 3.0g/kg group(Sample C) conversely showed higher plama IL-6 level than Control group. 3. LPS I.C.V. Injection increased plasma $TNF-{\alpha}$ level significantly in a dose-dependent manner compared with Normal group.(P<0.05) The plasma $TNF-{\alpha}$ concentration reached a significant maximal level about 1 hr after LPS(100ng/mouse) I.C.V. Injection.(P<0.001) 4. All Sample groups(0.5g/kg, 1.0g/kg, and 3.0g/kg) to which Coptidis Rhizoma was administered intragastrically with each constituent-dose 1 hr prior to LPS(100ng/mouse) I.C.V. Injection showed significant lower $TNF-{\alpha}$ plama level in 1 hr than Control group.(P<0.001) These data revealed that Coptidis Rhizoma might have anti inflammatory effect by reducing the plasma $TNF-{\alpha}$ level in a dose dependent manner in mice LPS I.C.V. Injection.

• Herbal Formula Science
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• v.12 no.1
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• pp.195-208
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• 2004

Objective: This study was conducted to investigate the effects of Aconiti Tuber on the plasma IL-6 and $TNF-{\alpha}$ level in mice stimulated by intracerebroventricular(I.C.V.) Injection of Lipopolysaccharide(LPS). Method: 6 mice were assigned to each of the normal group, the control group, and the experimental group. In the normal group only saline was administered intragastrically, and in the control group LPS was injected intracerebro-ventricularly 1 hr after intragastric administration of saline. In the experimental groups (Aconiti Tuber 0.5g/kg, Aconiti Tuber 1.0g/kg, Aconiti Tuber 3.0g/kg) each sample was administered intragastrically to mice 1 hr prior to the stimulation by LPS I.C.V. Injection. To measure the plasma IL-6 and $TNF-{\alpha}$ level of mice, their blood samples were collected from retro-orbital plexus, immediately centrifuged at $4^{\circ}C$, and plasma was removed and stored frozen at $-83^{\circ}C$ for later determination of plasma IL-6 and $TNF-{\alpha}$. Result : 1. LPS I.C.V. Injection increased plasma IL-6 level significantly in a dose-dependent manner compared with normal group(P<0.01). The plasma IL-6 concentration reached a significant maximal level about 1 hr after LPS I.C.V. Injection(P<0.001). LPS I.C.V. Injection increased plasma $TNF-{\alpha}$ level significantly in a dose-dependent manner(P<0.05). The plasma $TNF-{\alpha}$ concentration reached a significant maximal level about 1 hr after LPS I.C.V. Injection(P<0.001). 2. Sample A group to which Aconiti Tuber(0.5g/kg) was administered intragastrically 1 hr prior to the stimulation by LPS I.C.V. Injection showed insignificant lower plasma IL-6 level in 1 hr than control group(P<0.0635), and sample B group (Aconiti Tuber 1.0g/kg) showed significant lower plasma IL-6 level in 1 hr than control group(P〈0.05), and sample C group (Aconiti Tuber 3.0g/kg) showed significant lower IL-6 plasma level in 1 hr than control group(P<0.01). 3. sample A group to which Aconiti Tuber(0.5g/kg) was administered intragastrically 1 hr prior to the stimulation by LPS I.C.V. Injection showed insignificant lower plasma $TNF-{\alpha}$ level in 1 hr than control group(P>0.05), and Both sample B(1.0g/kg) and sample C(3.0g/kg) groups showed significant lower $TNF-{\alpha}$ plasma level in 1 hr than control group(P<0.01). These data revealed that Aconiti Tuber might have the anti inflammatory effect by reducing the plasma IL-6 and $TNF-{\alpha}$ level in a dose dependent manner in mice LPS I.C.V. Injection.

• Journal of the Korean Chemical Society
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• v.34 no.3
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• pp.239-247
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• 1990

The gas-phase S_N2$ reactions can be classified into neutral bimolecular, solvated, and ionic reactions; the neutral bimolecular reaction proceeds via retention mechanism whereas the ionic reaction produces inversion products. In the reaction of solvated nucleophile with one solvent molecule, a six-center transition state (TS) is formed and the two processes i.e., retention and inversion, are found to compete with a favored path depending on the electronic effect of the nucleophile and substituents in the substrate and on the steric requirement. In the ionic reaction, the difference in the energy barrier between the two processes reduces to a small value when the substrate methyl group is made bulky, leaving ability of the leaving group is improved and at the same time the negative charge of the nucleophile is dispersed. When the reaction center atom in the $S_N2$ reaction is changed to a larger sized second row elements, the activation barrier decreases since the steric crowding in the penta-coordinated TS is relieved. However within the same row, the barrier was found to increase as the atomic size decreased. For the boron, B, the barrier height was the least since in addition to the relatively large atomic size compared to C and N, it forms tetra-coordinated TS so that the steric crowding becomes nearly negligible.

• Journal of the Korean Chemical Society
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• v.18 no.2
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• pp.85-96
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• 1974

Extended H ckel Theory and CNDO/2 MO calculation methods have been applied to $C_6H_5YCH_2Cl$(Y = None, -$CH_2$-, -O-, -S-, -CO-, -$SO_2$-). It has been shown that charge distributions in molecules are mainly controlled by the migration of valence inactive electron, giving the order of ${\sigma}$-acceptor and ${\pi}$-donor effects -O- > -S- > -$CH_2$- > -$SO_2$-. The -CO- group exceptionally acts as ${\sigma}$-donor and ${\pi}$-acceptor. It was also predicted that, $S_N2$ reactivities of C$C_6H_5YCH_2Cl$ would be in the order of -O-${\thickapprox}$-CO- >>-S-${\thickapprox}$None > -$CH_2$-, neglecting solvent effect. From the results of our studies, we conclude that the structural factors influencing 의 $S_N$ reactivities will be: (1) positive charge developments on reaction center carbon atom (2) energy level of ${\sigma}$-antibonding unoccupied MO with respect to C-Cl bond. (3) ${\sigma}$-antibonding strength of C-Cl bond at that level.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.3
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• pp.297-302
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• 2022

We investigated the origin of magnetic behaviors induced by an asymmetric spin exchange interaction in Fe-site engineered lead iron niobate [Pb(Fe_1/2Nb_1/2)O₃, PFN], which exhibits a room-temperature multiferroicity. The magnitude of spin exchange interaction was regulated by the introduced transition metals with a distinct Bohr magneton, i.e., Cr, Co, and Ni. All compositions were found to have a single-phase perovskite structure keeping their ferroelectric order except for Cr introduction. We discovered that the incorporation of each transition metal imposes a distinct magnetic behavior on the lead iron niobate system; antiferro-, hard ferro-, and soft ferromagnetism for Cr, Co, and Ni, respectively. This indicates that orbital occupancy and interatomic distance play key roles in the determination of magnetic behavior rather than the magnitude of the individual Bohr magneton. Further investigations are planned, such as X-ray absorption spectroscopy, to clarify the origin of magnetic properties in this system.

• Herbal Formula Science
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• v.15 no.1
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• pp.185-197
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• 2007

Objective : This study was conducted to investigate the effects of Hwangryunhaedok-Tang and Geongangbuja-Tang on the change of interleukin-6 (IL-6) and tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$) level induced by LPS I.C.V. injection in mice. Method : We devided group into 6 mice and 6 mice were assingned to each group. In the normal group only saline was administered intragastrically, and in the control group LPS was injected intracerebroventricularly 1 hr after intragastric administration of saline. In the experiment groups Hwangryunhaedok-Tang(0.5g/kg, 1.0g/kg, 3.0g/kg) was administered intragastrically to mice 1 hr prior to LPS(100mg/mouse) I.C.V. injection.. Also Geongangbuja-Tang (0.5g/kg, 1.0g/kg, 3.0g/kg) was administered intragastrically to mice 1 hr prior to LPS(100mg/mouse) I.C.V. injection. To measure the plasma IL-6 and $TNF-{\alpha}$ level of mice, their blood samples were collected from retro-orbital plexus, immediately centrifuged at $4^{\circ}C$, and plasma was removed and stored frozen at $-83^{\circ}C$ for later determination of IL-6 and $TNF-{\alpha}$. The level of IL-6 and $TNF-{\alpha}$ production was measured by enzyme-linked immunosorbent assay in the plasma. Result : Regarding IL-6 level, The 0.5g/kg and the 1g/kg groups of Geongangbuja-Tang decreased IL-6 level. Especially the 3g/kg control group decreased IL-6 level significantly than the normal group(p<0.01). Regarding $TNF-{\alpha}$ level, the 3g/kg group of Geongangbuja-Tang decreased it significantly(p<0.05). Conclusion : These data revealed that Hwangryunhaedok-Tang might not have the anti imflammatory effect and Geongangbuja-Tang(3g/kg)might have the anti imflammatory effect by reducing the plasma IL-6 and $TNF-{\alpha}$ level in mice LPS Injection.EIM (Eighteen Incompatible Medicaments) is an important component in Oriental pharmacology and is directly related to clinical prescriptions. Medical practitioners argued that the definite cause and meaning of EIM was ambiguous and therefore debated the issue of clinical application of the EIM. This study conducted an in-depth literary research on the origin, meaning and contents of EIM with the purpose to contribute in its efforts to be used clinically. Even after thousands of years have past since establishment of Oriental medicine, EIM is still tabooed and was an obstacle that hindered ideologies. Modern herbal medicine texts claim that the use of EIM can reduce treatment effects and promote poisoning and side effects. However, since long ago, there has been medical practitioners who reject this as false. Recently, poisoning caused by EIM has been claimed to be from the toxicity of the drug itself, rather than the result of interaction between the drugs, and therefore they suggest that EIM is not a forbidden domain. In addition, EIM showed a difference in number depending on the era. However, this can be understood not as a definite number, but instead as a warning to be careful during combination of drugs for use as clinical medicine. Historically, there were very few cases in which EIM was used for clinical tests and thus, the clinical value is not, while others applied EIM directly to their bodies, which showed signs for the usefulness and potential of EIM for us. A more concrete and in-depth study must be made on EIM.