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정경수,이대우,양희정,이순철,김길현 충남대학교 약학대학 의약품개발연구소 1994 藥學論文集 Vol.10 No.-
To ellucidate immunologic activities of ginseng saponin, the splenic leukocytes of BALB/c mice were incubated in RPMI medium for 48hr with or without ginseng total saponin(GTS), and then analyzed flow cytometrically. Upto the concentration of 100㎍/㎖, GTS exherted stimulatory effect on the immune cells most prominently on B cells: the percentage of the surface Immunoglobulin (sIg) -positive cells (B cells) of the control was 47.l%, while that of GTS treated was 58.9%. The percentages of monoclonal antibody(mAb) J1j-reactive cells (T cells) were 28.8% and 3l.3%, those of mAb Gkl.5-reactive cells (CD4' T cells) were l8.5% and l9.l%, and those of mAb M1/70-reactive cells (mostly macrophages) were 4.4 and 5.0% at the concentration of 0 and 100㎍/㎖, respectively. However, at the concentration of 300㎍/㎖ or higher, GTS was found to be toxic to the immune cells especially to B cells in that the flow rate of the cells (gated viable cells) significantly decreased and the percentage of B cells droped from 58.9% to 31.2% and 25.4% at l00, 300, and 1000㎍/㎖, respectivelly. These data strongly suggests that GTS would exhert B-cell mitogen-like activity at physiological concentrations of 100㎍/㎖ or lower.
꽃송이버섯 열수 추출물을 포함하는 조합물들의 항암면역활성
정경수,이우찬 충남대학교 약학대학 의약품개발연구소 2005 藥學論文集 Vol.20 No.-
In order to develope a new composite to be used as immunopotentiating health food, the composites including extracts of Sparassis crispa, Grifola frondosa, Phellinus linteus, red ginseng, and Oxya japonica were prepared and tested for their antitumor immunoactivities. Of these, the composite G3, which contained the extracts of S. crispa (20%), G. frondosa (55%), P. linteus (5%), red ginseng (10%), and O. japonica (10%), showed marked lymphoblastogenic activity on the in vitro cultured BALB/c mouse splenic lymphocytes and successfully suppressed the growth of sarcoma 180 cells implanted into the peritoneum of ICR mice. Moreover, the composite G3 exerted antitumor activity against sarcoma 180 tumor cells subcutaneously implanted into the left groin of ICR mice with the tumor inhibition ratio of 46.2%.
Phellinus linteus 균사 배양물로부터 분리한 단백다당체 Kp의 항암활성
정경수,김신숙,김희수,한만우,김병각 충남대학교 약학대학 의약품개발연구소 1994 藥學論文集 Vol.10 No.-
A protein-polysaccaride fraction Kp(53.9% polysaccharide, 14.2% protein) was separated from the shake-cultured mycelia of a basidiomycetous fungus, Phellinus linteus, and its antitumor activity against sarcoma 180 in ICR mice was investigated. When administered after the tumor implantation. Kp exerted antitumor activity by inhibiting the growth of the sarcoma 180 solid tumor by 71.5% and increasing the life span of the sarcoma 180 ascitic mice by 51.5% at 100 ㎎/㎏. In pretreatment tests, in which Kp was administered once daily for 9 days before the tumor implantation. Kp inhibited the growth of the solid and ascites form of sarcoma 180, respectively, by 35.4% and by 80.3% at 100 ㎎/㎏. However, Kp showed no in vitro cytotoxic activity against a murine leukemia L1210 and a human gastric tumor SNU.1 upto the concentration of 200 ㎍/㎖. From these results, it is clear that the antitumor activity of Kp is exerted through its immunomodulating activity on the host's immune system.
Kyeong Woo Chung,Ho-Sung Yoon,Chul-Joo Kim,Jin Young Lee,Rajesh Kumar Jyothi 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.83 No.-
The technology for extraction and recovery of the thorium from its source is one of the significant areas ofresearch Present investigation deals on development of a process for extraction of thorium and itsseparation from the uranium and rare earths contained Korean monazite leach liquor. In the preliminarystudy, sulfuric acid treatment of monazite concentrate followed by water leaching was carried out. Furthermore double salt precipitation and acid leaching lead to produce thorium rich leach liquor. Various commercial extractants accomplishing D2EHPA, PC88A, Amine and Primene JM-T were testedand optimized for selective separation of thorium. The effective extraction behavior of thorium followedthe order as; Primene JM-T > D2EHPA > PC88A and high separation factor was resulted at high acidity(2.5 mol/L) of leach liquor, ensuring on high selectivity of Primene JM-T towards loading of Th. Theco-extraction of cerium was prevented by changing thorium oxidation state using Fe2+ and H2O2 andreported. The co-extraction of other associated rare earths was scrubbed with sulfuric acid solutions. Subsequently, stripping studies were carryout with two different types of mineral acids and it wasquantitative using high acid concentration (5 mol/L).
The effect of ultrasound on the sulfuric acid leaching of uranium by use of MnO2 as a oxidant
Chung Kyeong Woo,Yoon Ho-Sung,Kim Chul-Joo,Jeon Ho-SeoK 한국자원공학회 2021 Geosystem engineering Vol.24 No.6
The paper reported sonochemical leaching of uranium from black shale in Fe2+-containing sulfuric acid solution of pH 2 using MnO2 as an oxidant. Ultrasound enhanced uranium leaching at the initial time but suppressed it over a prolonged time. In addition, the amount of MnO2-input was increased for ultrasonic leaching than conventional leaching at the same time. It was understood that ultrasonic leaching conditions should be optimized to achieve a positive effect. Faster leaching of uranium and reduced consumption of MnO2 could be found under the optimum condition of leaching up to ca. 85% at the sonication power of 25 W.
Oxidation Behavior of Ni_xFe_(1-x)(OH)_2 in Cl^- -containing Solutions
Chung, Kyeong Woo,Kim, Kwang Bum 한국부식방식학회 2003 Corrosion Science and Technology Vol.2 No.3
The addition of Ni leads to the formation of protective rust layer on steel and subsequently high corrosion resistance of steel in (Cl)^--containing environment. α-FeOOH, β-FeOOH, γ-FeOOH and Fe₃O₄ are formed mainly on steels exposed to (Cl)^--containing environment. As the first work of this kind, this study reports the influence of Ni on the oxidation behavior of Ni_xFe_(1-x)(OH)₂ in (Cl)^--containing solution at two different pH regions(condition Ⅰ under which the solution pH is allowed to decrease and condition Ⅱ under which solution pH is maintained at 8) where γ-FeOOH and Fe₃O₄ are predominantly formed, respectively, upon oxidation of Fe(OH)₂. In the presence of Ni(Ⅱ) in the starting solution, the formation of β-FeOOH was facilitated and the formation of γ-FeOOH was suppressed with increasing Ni(Ⅱ) content and with increasing oxidation rate of Fe(Ⅱ). Ni(Ⅱ) was found to have Fe₃O₄-suppressing effect under condition Ⅱ.
정경우(Chung, Kyeong-Woo),김세융(Kim, Se-Yung),양유창(Yang, Yoo-Chang),안승균(Ahn, Seung-Gyun),전유택(Jeon, Yoo-Taek),나상묵(Na, Sang-Mook) 한국신재생에너지학회 2006 한국신재생에너지학회 학술대회논문집 Vol.2006 No.11
Bipolar plate, which forms about 50% of the stack cost, is an important core part with polymer electrolyte membrane in PEMFC. Bipolar plates have been commonly fabricated from graphite meterial having high electrical conductivity and corrosion resistance. Lately, many researchers have concentrated their efforts on the development of metallic bipolar plate and stainless steel has been considered as a potential material for metallic bipolar plate because of its high strength, chemical stability, low gas permeability and applicability to mass production. However, it has been reported that its inadequate corrosion behavior under PEMFC environment lead to a deterioration of membrane by dissolved metal ions and an increase in contact resistance by the growth of passive film therefore, its corrosion resistance as well as contact resistance must be improved for bipolar plate application. In this work, several types of coating were applied to 316L and their electrical conductivity and corrosion resistance were evaluated In the simulated PEMFC environment. Application of coating gave rise to low interfacial contact resistances below 19m{Omega}cm² under the compress force of 150N/cm². It also made the corrosion potential to shift in the posit ive direct ion by 0.3V or above and decreased the corrosion current from ca. 9{mu}A/cm² to ca. 0.5{mu}A/cm² in the mixed solution of 0.1N;N₂SO₄ and 2ppm HF A coat ing layer under potentiostatic control of 0.6V and 0.75V_{SCE} for 500 hours or longer showed some instabilities, however, no significant change in coat Ing layer were observed from Impedance data. In addition, the corrosion current maintained less than 1{mu}A/cm² for most of time for potentiostatic tests. It indicates that high electrical conductivity and corrosion resistance can be obtained by application of coatings in the present work.