• 제목/요약/키워드: $U_3 O_8$

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참느릅나무의 성분에 관한 연구 (Studies on the Constituents of Ulmus parvifolia)

  • 문영희;임기룡
    • 생약학회지
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    • 제26권1호
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    • pp.1-7
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    • 1995
  • The bark of Ulmus parvifolia Jacq. (Ulmaceae) has been used for the treatment of gonorhea, edema, scabies and eczema marginatum. Previous investigations conducted with the heartwood and leaves have demonstrated it to contain sesquiterpenes as well as fat acids from the heartwood and flavonol glycosides from leaves. However, no phytochemical work has been done on the bark parts of this plant. Investigation of the phytochemical constituents in the barks of U. parvifolia has resulted in the isolation of sterols, sterol glucoside and a catechin glycoside, $(+)-catechin\;7-O-{\alpha}-{_L}-rhamnopyranoside$, all of which were isolated for the first time from this plant. Sterols were consisted of the three components, ${\beta}-sitosterol$, stigmasterol and campesterol in a ratio of 92.1:4.1:3.8, and sterol glucoside was identified as ${\beta}-sitosterol\;3-O-{\beta}-{_D}-glucoside$. The structure of the catechin $7-O-{\alpha}-{_L}-rhamnoside$ was established primarily by analysis of $^1H-and$ COSY-45 NMR, HMQC and HMBC and EI mass spectra of the heptaacetate. Especially, HMBC spectrum provides effective way for the determination of the point of attachment of the rhamnosyl group to catechin moiety.

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Metabolic Engineering of Escherichia coli for the Biological Synthesis of 7-O-Xylosyl Naringenin

  • Simkhada, Dinesh;Kim, EuiMin;Lee, Hei Chan;Sohng, Jae Kyung
    • Molecules and Cells
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    • 제28권4호
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    • pp.397-401
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    • 2009
  • Flavonoids are a group of polyphenolic compounds that have been recognized as important due to their physiological and pharmacological roles and their health benefits. Glycosylation of flavonoids has a wide range of effects on flavonoid solubility, stability, and bioavailability. We previously generated the E. coli BL21 (DE3) ${\Delta}pgi$ host by deleting the glucose-phosphate isomerase (Pgi) gene in E. coli BL21 (DE3). This host was further engineered for whole-cell biotransformation by integration of galU from E. coli K12, and expression of calS8 (UDP-glucose dehydrogenase) and calS9 (UDP-glucuronic acid decarboxylase) from Micromonospora echinospora spp. calichensis and arGt-4 (7-O-glycosyltransferase) from Arabidopsis thaliana to form E. coli (US89Gt-4), which is expected to produce glycosylated flavonoids. To test the designed system, the engineered host was fed with naringenin as a substrate, and naringenin 7-O-xyloside, a glycosylated naringenin product, was detected. Product was verified by HPLC-LC/MS and ESI-MS/MS analyses. The reconstructed host can be applied for the production of various classes of glycosylated flavonoids.

PDMS 채널 내부에 성장된 산화아연 나노막대를 이용한 H7N9 인플루엔자 바이러스 전기화학 면역센서 (Electrochemical Immunosensor Based on the ZnO Nanorods Inside PDMS Channel for H7N9 Influenza Virus Detection)

  • 한지훈;이동영;박정호
    • 센서학회지
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    • 제23권4호
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    • pp.278-283
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    • 2014
  • In this study, we propose an immunosensor using zinc oxide nanorods (NRs) inside PDMS channel for detecting the influenza A virus subtype H7N9. ZnO with high isoelectric point (IEP, ~9.5) makes it suitable for immobilizing proteins with low IEP. In this proposed H7N9 immunosensor structure ZnO NRs were grown on the PDMS channel inner surface to immobilize H7N9 capture antibody. A sandwich enzyme-linked immunosorbent assay (ELISA) method with was used 3,3',5,5' tetramethylbenzidine (TMB) for detecting H7N9 influenza virus. The immunosensor was evaluated by amperometry at various H7N9 influenza antigen concentrations (1 pg/ml - 1 ng/ml). The redox peak voltage and current were measured by amperometry with ZnO NWs and without ZnO NWs inside PDMS channel. The measurement results of the H7N9 immunosensor showed that oxidation peak current of TMB at 0.25 V logarithmically increased from 2.3 to 3.8 uA as the H7N9 influenza antigen concentration changed from 1 pg/ml to 1 ng/ml. And then we demonstrated that ZnO NRs inside PDMS channel can improve the sensitivity of immunosensor to compare non-ZnO NRs inside PDMS channel.

한국인(韓國人) 성인(成人) 치열궁(齒列弓)의 형태학적(形態學的) 연구(硏究) (A Morphological Study of Dental Arches in Korean Adults)

  • 우상민
    • 대한치과보철학회지
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    • 제8권1호
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    • pp.30-36
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    • 1968
  • The measurements on the various items, such as arch form, kinds of anterior dental arch, degree of curvature in anterior dental arches, relationship between direction of the disto-incisal edge of the canine and first premolar, and kinds of posterior dental arch in upper dental arches were studied on 311 cases of the Korean adults aged from 20 to 30years. The results were as follows. 1. The commonest type of the upper dental arches was U-type (53.7%), the remaining were O-type (25.4%) and V-type (20.0%). 2. A slight curvature type (71.87%) prevailed against angulated curvature type in upper anterior dental arches. 3. The degree of curvature from $121^{\circ}$ to $160^{\circ}$ in anterior dental arches was common, and the degree of curve of 1-type with on curvature was smaller than 4, 5 type with two curvature. 4. The direction of the disto-incisal edge of canine went between the tip of the buccal cusp and the lingual incline of the buccal cusp of the first premolar in most dental arches and went lingual incline of the buccal cusp of the first premolar in U-type, from buccal cusp to lingual cusp of the first premolar in O-type and were distributed from buccal edge to central groove of the first premolar in V-type. 5. A posterior dental arch with almost straight curvature was common in 60.87%, and 4-type with a half rounded curve from first premolar to second molar was next.

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Investigation of Pellet-Clad Mechanical Interaction in Failed Spent PWR Fuel

  • Jung, Yang Hong;Baik, Seung Je
    • Corrosion Science and Technology
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    • 제18권5호
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    • pp.175-181
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    • 2019
  • A failed spent fuel rod with 53,000 MWd/tU from a nuclear power plant was characterized, and the fission products and oxygen layer in the pellet-clad mechanical interaction region were observed using an EPMA (Electron Probe Micro-Analyzer). A sound fuel rod burned under similar conditions was used to compare and analyze, the results of the failed fuel rod. In the failed fuel rod, the oxide layer represented $10{\mu}m$ of the boundary of the cladding, and $35{\mu}m$ of the region outside the cladding. By comparison, in the sound fuel rod, the oxide layer was $8{\mu}m$, observed in the cladding boundary region. The cladding inner surface corrosion and the resulting fuel-cladding bonding were investigated using an EPMA. Zirconium existed in the bonding layer of the (U, Zr)O compound beyond the pellet cladding interaction gap of $20{\mu}m$, and composition of UZr2O3 was observed in the failed fuel rod. This paper presents the results of the EPMA examination of a spent fuel specimen, and a technique to analyze fission products in the pellet-clad mechanical interaction region.

충남탄전, 대동누층군의 셰일과 탄질암에 관한 암석화학 및 환경지구화학적 특성 (Petrochemistry and Environmental Geochemistry of Shale and Coal from the Daedong Supergroup, Chungnam Coal Field, Korea)

  • 이찬희;이현구;김경웅
    • 자원환경지질
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    • 제30권5호
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    • pp.417-431
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    • 1997
  • Characteristics of sedimentary rocks and enrichment of toxic elements in shale and coal from the Chungnam coal field were investigated based upon geochemistry of major, trace and rare earth elements. Shale and coal of the area are interbedded along the Traissic to the Jurassic Daedong Supergroup, which can be subdivided into grey shale, black shale and coal. The coal had been mined, however all the mines are abandonded due to the economic problems. The shale and coal are characterized by relatively low contents of $SiO_2$, and $Al_2O_3$ and high levels of loss-on-ignition (LOI), CaO and $Na_2O$ in comparison with the North American Shale Composite (NASC). Light rare earth elements (La, Ce, Yb and Lu) are highly enriched with the coal. Ratios of $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ in shale and coal range from 30.0 to 351.8 and from 4.2 to 106.8, which have partly negative correlations against $SiO_2/Al_2O_3$ (1.24 to 6.06), respectively. Those are suggested that controls of mineral compositions in shale and coal can be due to substitution and migration of those elements by diagenesis and metamorphism. Shale and coal of the area may be deposited in terrestrial basin deduced from high C/S (39 to 895) and variable composition of organic carbon (0.39 to 18.40 wt.%) and low contents of reduced sulfur (0.01 to 0.05 wt.%). These shale and coal were originated from the high grade metamorphic and/or igneous rocks, and the rare earth elements of those rocks are slightly influenced with diagenesis and metamorphism on the basis of $Al_2O_3$ versus La, La against Ce, Zr versus Yb, the ratios of La/Ce (0.38 to 0.85) and Th/U (3.6 to 14.6). Characteristics of trace and rare earth elements as Co/Th (0.07 to 0.86), La/Sc (0.31 to 11.05), Se/Th (0.28 to 1.06), V/Ni (1.14 to 3.97), Cr/V (1.4 to 28.3), Ni/Co (2.12 to 8.00) and Zr/Hf (22.6~45.1) in the shale and coal argue for inefficient mixing of the simple source lithologies during sedimentation. These rocks also show much variation in $La_N/Yb_N$ (1.36 to 21.68), Th/Yb (3.5 to 20.0) and La/Th (0.31 to 7.89), and their origin is explained by derivation from a mixture of mainly acidic igneous and metamorphic rocks. Average concentrations in the shale and coal are As=7.2 and 7.5, Ba=913 and 974, Cr=500 and 145, Cu=20 and 26, Ni=38 and 35, Pb=30 and 36, and Zn=77 and 92 ppm, respectively, which are similar to those in the NASC. Average enrichment indices for major elements in the shale (0.79) and coal (0.77) are lower than those in the NASC. In addition, average enrichment index for rare earth elements in coal (2.39) is enriched rather than the shale (1.55). On the basis of the NASC, concentrations of minor and/or environmental toxic elements in the shale and coal were depleted of all the elements examined, excepting Cr, Pb, Rb and Th. Average enrichment indices of trace and/or potentially toxic elements (As, Cr, Cu, Ni, Pb, U and Zn) are 1.23 to 1.24 for shale and 1.06 to 1.22 for coal, respectively.

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Artemia 공급 단계에서 은어(Plecoglossus altivelis), 조피볼락(Sebastes schlegeli ), 감성돔(Acanthopagrus schlegeli ) 및 넙치(Paralichthys olivaeus)의 소화효소 활성 (Comparative Study of Digestive Enzyme in the Artemia Feeding Step of the Sweet Fish Plecoglossus altivelis, Rock Fish Sebastes schlegeli, Black Seabream Acanthopagrus schlegeli, and Olive Flounder Paralichthys olivaeus)

  • 이배익;김이청;김근업;권오남
    • 한국수산과학회지
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    • 제45권1호
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    • pp.50-55
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    • 2012
  • We compared the nutritional requirements of whole larvae of the black seabream Acanthopagrus schlegeli, sweet fish Plecoglossus altivelis, olive flounder Paralichthys olivaeus and rock fish Sebastes schlegeli. The larvae were 20, 30, 14 and 5 DAH (or spawning) of black seabream, sweet fish, olive flounder and rock fish, respectively. Specific ${\alpha}$-amylase activity (mU/mg protein) was highest (8,324.9 mU/mg protein) in rock fish larvae (P<0.05). Specific trypsin-like protease activity was highest (11,330.1 mU/mg protein) in black seabream larvae (P<0.05), which also exhibited the highest activity, 685.5 mU/mg dry weight (P<0.05). The specific activities per mg protein and mg dry weight of black seabream were the highest (187.4 mU/mg protein and 11.3 mU/mg dry weight, respectively) (P<0.05). A/P, P/L and A/L ratios of rock fish were 1.47, 90.3 and 133.1, respectively (P<0.05). We present here basic larval digestive enzymatic nutritional requirement data.

THE BRIGHT PART OF THE LUMINOSITY FUNCTION FOR HALO STARS

  • Lee, Sang-Gak
    • 천문학회지
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    • 제28권2호
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    • pp.139-146
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    • 1995
  • The bright part of the halo luminosity function is derived from a sample of the 233 NLTT propermotion stars, which are selected by the 220 km/ see of cutoff velocity in transverse to rid the contamination by the disk stars and corrected for the stars omitted in the sample by the selection criterion. It is limited to the absolute magnitude range of $M_v=4-8$, but is based on the largest sample of halo stars up to now. This luminosity function provides a number density of $2.3{\cdot}10^{-5}pc^{-3}$ and a mass density of $2.3{\cdot}10^{-5}M_{o}pc^{-3}$ for 4 < $M_v$ < 8 in the solar neighborhood. These are not sufficient for disk stability. The kinematics of the sample stars are < U > = - 7 km/sec, < V > = - 228 km/sec, and < W > = -8 km/sec with (${\sigma_u},{\sigma_v},{\sigma_w}$) = (192, 84, 94) km/sec. The average metallicity of them is [Fe/H] = $- 1.7{\pm}0.8$. These are typical values for halo stars which are selected by the high cutoff velocity. We reanalyze the luminosity function for a sample of 57 LHS proper-motion stars. The newly derived luminosity function is consistent with the one derived from the NLTT halo stars, but gives a somewhat smaller number density for the absolute magnitude range covered by the LF from NLTT stars. The luminosity function based on the LHS stars seems to have a dip in the magnitude range corresponding to the Wielen Dip, but it also seems to have some fluctuations due to a small number of sample stars.

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A NOTE ON WEAKLY IRRESOLUTE MAPPINGS

  • Chae, Gyu-Ihn;Dube, K.K.;Panwar, O.S.
    • East Asian mathematical journal
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    • 제1권
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    • pp.89-100
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    • 1985
  • A mapping f: X$\rightarrow$Y is introduced to be weakly irresolute if, for each x $\varepsilon$ X and each semi-neighborhood V of f(x), there exists a semi-neighborhood U of x in X such that $f(U){\subset}scl(V)$. It will be shown that a mapping f: X$\rightarrow$Y is weakly irresolute iff(if and only if) $f^{-1}(V){\subset}sint(f^{_1}(scl(V)))$ for each semiopen subset V of Y. The relationship between mappings described in [3,5, 6,8] and a weakly irresolute mapping. will be investigated and it will be shown that every irresolute retract of a $T_2$-space is semiclosed.

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대자석의 품질기준(品質基準) 및 포제전후의 성질비교 (Study for the Standardization of Haematite and Comparison Property before and after Haematite Processing)

  • 이장천
    • 대한한의학방제학회지
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    • 제12권1호
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    • pp.177-193
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    • 2004
  • Objectives: This study has been done to compare the Haematite's composition before and after using processing method and to clarify its quality and naming through the historical herbal books. Methods: I studied the Haematite and processed Haematite using physical and chemical methods which contain microscopic analysis, X-ray diffraction analysis, thermal analysis, XRF, ICP, etc, to compare the compositions and its characters. Results: Haematite is a metallic oxide(Hematite, $Fe_2O_3$). Haematite contains a main ingredients of crude Haematite Fe 40.336% - 62.174%, processed Haematite $50.499%{\sim}62.791%$(a theory value is 69.944% the korean pharmacopoeia wants >45%) and small ingredients, also. Conclusion: A radio-element contents of U, Th contain less than average contents of the lithosphere's U 1.8ppm, Th 7.2ppm.

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