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Lee, Hyung-Chul,Hwang, Sang-Gu,Lee, Young-Gu,Sohn, Hyung-Ok,Lee, Dong-Wook,Hwang, Seok-Youn,Kwak, Yi-Swong,Wee, Jae-Joon,Joo, Woo-Hong,Cho, Yong-Kweon,Moon, Ja-Young Institute of Genetic Engineering Changwon National 2002 Gene and Protein Vol.6 No.-
The effects of the subchronic administration of Panax ginseng extracts were examined on the hepatic cytochrome P450-dependent monooxygenase system of guinea pigs pre-exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Panax ginseng extracts were intraperitioneally administered to guinea pigs at 100 ㎎/㎏/day for 14 days from 1 week after a single intraperitoneal injection of 1 ㎍ of TCDD/㎏ of body weight. TCDD treatment increased the total cytochrome P450 content 2.86-fold, and this was remarkably inhibited by the administration of Panax ginseng extracts. Treatment with ginseng extract alone also decreased the contents of cytochrome P450 by 33%, but both TCDD and ginseng extracts had no effect on cytochrome b_5 content. The administration of TCDD resulted in a 1.73-fold increase in microsomal NADPH-cytochrome P450 reductase activity in the guinea pig liver, and this was significantly inhibited by ginseng extracts, but treatment with ginseng extracts alone had no effect on its activity, and no statistical changes in the activity of NADPH-cytochrome b_5 reductase were observed in guinea pig liver due to TCDD and/or ginseng extract administration. Compared to the control, ECOD activity remarkably (1.76-fold) increased after TCDD administration, but this increase was completely inhibited by treatment with ginseng extract. Treatment with ginseng extract alone resulted in a 50% reduction of ECOD activity. TCDD administration remarkably induced benzphetamine demethylation (BPDM) activity, while ginseng extract also slightly increased the enzyme's activity, but the induction attributed to ginseng extracts was not statistically significant. Even though administration of ginseng extracts slightly inhibited TCDD-induced BPDM activity, the inhibition was not statistically significant. These results indicate that ginseng extract exerts different effect on the induction of P450 isozymes. From these results, we suggest that panax ginseng extracts may act as an inhibitor of CYPIA rather than that of CYP2B. ⓒ 2002 Elsevier Science Inc. All right reserved.
Lee, Ki-Hyoung,Park, Sang-gyu,Kim, Min-Chul,Lee, Bong-Sang,Wee, Dang-Moon Elsevier 2011 Materials science & engineering. properties, micro Vol.529 No.-
<P><B>Highlights</B></P><P>► We offer information for determining optimum alloying contents of SA508 Gr.4N steel. ► This study shows improvement of toughness with increasing Ni and Cr contents. ► Ni content is more effective on the impact toughness than on the fracture toughness. ► Cr content is more effective on the fracture toughness. ► We offer detailed information on relationship between toughness and microstructure.</P> <P><B>Abstract</B></P><P>SA508 Gr.4N Ni–Cr–Mo low alloy steel, in which Ni and Cr contents are higher than in commercial reactor pressure vessel (RPV) steels, may be a candidate RPV material with the improved strength and toughness due to its tempered martensitic microstructure. This study aims at assessing the effects of microstructural factors with alloying element contents on the transition properties of Ni–Cr–Mo low alloy steels. Model alloys with different Ni and Cr contents were fabricated and their Charpy impact toughness and fracture toughness were examined in the transition region according to ASTM E23 and E1921 standard procedures, respectively. The test results showed extensive improvements of both impact toughness and fracture toughness with increasing Ni and Cr contents. However, Ni content was more effective on the impact toughness than on the fracture toughness, while Cr content was more effective on the fracture toughness. In order to identify a difference in effects of alloying elements contents on the fracture toughness and impact toughness, the relations between the transition properties and the scale of the microstructural features such as packets and carbides are discussed in detail.</P>
Lee, Chul-Wee Korean Magnetic Resonance Society 2002 Journal of the Korean Magnetic Resonance Society Vol.6 No.2
The chalcogenide glass (ALS, $Al_2S_3-La_2S_3$) was prepared by melting a stoichiometric mixture of aluminum powder and $La_2S_3$ under $H_2S$ atmosphere at $1200{\circ}C$. Glasses containing 0.1-0.1% of $Mn^{2+},\;Gd^{3+}$ and $Cu^{2+}$ were also prepared. The characteristic features of the ESR spectra for the transition metal containing ALS glasses are interpreted.
O-Acylation of Heteropolyanions Containing Two Adjacent Vanadium Atoms
Lee, Chul-Wee,So, Hyun-Soo,Lee, Kyu-Ryong Korean Chemical Society 1988 Bulletin of the Korean Chemical Society Vol.9 No.6
Reaction of Keggin- or Dawson-type heteropolyanions containing two adjacent vanadium atoms with acetic anhydride in the presence of acid produced acylated anions. Heteropolyanions with one or no vanadium atom do not react under the same conditions, indicating that the acyl group is attached to the bridging oxygen atom between the two vanadium atoms. A characteristic infrared band at 1760 $cm^{-1}$ was observed for the acylated anions. The 8-line EPR spectrum shows that one of the vanadium atoms is reduced to V(IV ). The acylated heteropolyanions are easily hydrolyzed, and its acyl group can also be transferred to aniline.
Lee,Hyung Chul,Hwang,Sang Gu,Lee,Young Gu,Sohn,Hyung Ok,Lee,Dong Wook,Kwak,Yi Swong,Wee,Jae Joon,Joo,Woo Hong,Cho,Yong Kweon,Moon,Ja Young 한국생명과학회 2001 한국생명과학회 학술발표회 Vol.33 No.-
The effects of the subchronic administration of panax ginseng extracts were examined on the hepatic cytochrome P450-dependent monooxygenase system of guinea pigs preexposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Panax ginseng extracts were intraperitoneally administered to guinea pigs at 100 ㎎/㎏/day for 14 days from 1 week after a single intraperitoneal injection of 1μg of TCDD/㎏ of body weight. TCDD treatment increased the total cytochrome P450 content 2.86-fold, and this was remarkably inhibited by the administration of panax ginseng extracts. Treatment with ginseng extract alone also decreased the contents of cytochrome P450 by 33%, but both TCDD and ginseng extracts had no effect on cytochrome b5 content. The administration of TCDD resulted in a 1.73-fold increase in microsomal NADPH-cytochrome P450 reductase activity in the guinea pig liver, and this was significantly inhibited by ginseng extracts, but treatment with ginseng extracts alone had no effect on its activity, and no statistical changes in the activity of NADPH-cytochrome b_5 reductase were observed in guinea pig liver due to TODD and/or ginseng extract administration. Compared to the control, ECOD activity remarkably (1.76-fold) increased after TCDD administration, but this increase was completely inhibited by treatment with ginseng extract. Treatment with ginseng extract alone resulted in a 50% reduction of ECOD activity. TCDD administration remarkably induced benzphetamine demethylation (BPDM) activity, while ginseng extract also slightly increased the enzymes activity, but the induction attributed to ginseng extracts was not statistically significant. Even though administration of ginseng extracts slightly inhibited TCDD-induced BPDM activity, the inhibition was not statistically significant. These results indicate that ginseng extract exerts different effect on the induction of P450 isozymes. From these results, we suggest that panax ginseng extracts may act as an inhibitor of CYP1A rather than that of CYP2B.
Lee, Ki-Hyoung,Kim, Min-Chul,Lee, Bong-Sang,Wee, Dang-Moon Elsevier 2010 Materials science & engineering. properties, micro Vol.527 No.15
<P><B>Abstract</B></P><P>This study aims at assessing the fracture toughness behavior of tempered martensitic Ni–Mo–Cr low alloy steels for reactor pressure vessels in a transition temperature region using a master curve approach. The fracture toughness tests for model alloys with various chemical compositions were carried out following ASTM E1921-08. The microstructures, tensile properties, and Charpy impact toughness were also evaluated. Alloying elements such as Ni, Cr, and Mo affected the mechanical properties of alloys from changes in the phase fraction and precipitation behavior. In the fracture toughness test results, the data sets showed a deviation from the median curve and a smaller scatter than that of the prediction of the ASTM standard, especially in the lower transition region. The exponential parameter of the master curve equation was adjusted by an exponential fitting to data sets for expressing well the temperature dependency of the fracture toughness. The adjusted parameter provided good agreement for data distribution and the independence of <I>T</I><SUB>0</SUB> from test temperatures through an overall temperature range in contrast with the results from the standard master curve.</P>
Lee, Chul-Wee,So, Hyun-Soo,Lee, Kyu-Ryong Korean Chemical Society 1986 Bulletin of the Korean Chemical Society Vol.7 No.2
The solution epr spectra of ${\alpha}-1,2,3-[H_nPV(IV)V_2W_9O_{40}]^{(7-n)-}$were measured at various pH and three protonated species have been identified. The spectrum of $H_3PV(IV)Ⅴ_2$ consisting of 8 lines indicates that the V-OH-V bridge prevents effectively the electron transfer between the vanadium atoms. The spectrum of $H_2PV(IV)V_2$ consisting of 15 lines can be interpreted by assuming that the electron is hopping fast between the two vanadium atoms in the V-O-V sequence. The multi-line spectrum of $HPV(IV)V_2$ is interpreted as a poorly resolved 43-line spectrum which originates from the electron hopping among the three vanadium atoms with the forward and backward transition probabilities of 4:1 in the OH-V-O-V sequence.
Lee, Chul Wee,Yu, Jong-Sung,Larry Kevan 순천대학교 기초과학연구소 1992 基礎科學硏究誌 Vol.3 No.-
Dehydration, oxidation-reduction, and adsorbate (D_2O, CD_3OH, CO) interactions of PdSAPO_11 prepared by adding Pd(NH_3)_4Cl_2 during the synthesis of SAPO-11 have been studied and compared with (S)PdH-SAPO-11 and (i) PdH-SAPO-11 where (S) and (i) refer to solid-state ion exchange and impregnation, respectively. Diffuse reflectance spectra, electron spin resonance (ESR), and electon spin echo modulation (ESEM) spectroscopies are almost the same for the three differently prepared Pd-containing samples. ESR spectra of dehydrated samples at 600℃ show g_1=2.9 and 2.6 and g_1=2.1, which are assigned to two Pd(I) species. Adsorption of water on dehydrated samples induces decomposition of water and the formation of a Pd-oxygen radical complex. ESEM shows that, after adsorption of CD_3OH, the g_1=2.9 component of Pd(I) disappears and the g_1=2.6 Pd(I) coordinates to one methanol with a Pd-D distance of 0.39-0.40 nm. Pd(II) in SAPO-11 is reduced to Pd(I) by CO and forms at least two different Pd(I)-carbonyl complexes. Within the range of 0.5-1.0 mol % Pd in PdSAPO-11, it is most probable that the Pd ions are not in framework positions.
Epr Study of the 10-Tungsto-2-vanado(Ⅳ, Ⅴ)phosphate Anion, [PV(Ⅳ)VW$_{10}O_{40}]^{6-}$
Lee, Chul-Wee,So, Hyun-Soo,Lee, Kyu-Ryong Korean Chemical Society 1986 Bulletin of the Korean Chemical Society Vol.7 No.1
The polycrystalline epr spectrum of ${\alpha}-1,\;2-[PV(IV)VW_{10}O_{40}]^{6-}$ doped into host crystals and its solution spectrum are reported. The solution spectrum consists of fifteen lines, indicating that the unpaired electron is hopping fast between the two vanadium atoms. The polycrystalline spectrum, which consists of three sets of fifteen lines, was analyzed as a spectrum of an I = 7 system and the epr parameters were determined. The spectrum cannot be interpreted by assuming that each line appears at the average magnetic field of two hyperfine lines expected for two uncoupled vanadium atoms.