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      • A SUB-SATURN MASS PLANET, MOA-2009-BLG-319Lb

        Miyake, N.,Sumi, T.,Dong, Subo,Street, R.,Mancini, L.,Gould, A.,Bennett, D. P.,Tsapras, Y.,Yee, J. C.,Albrow, M. D.,Bond, I. A.,Fouqué,, P.,Browne, P.,Han, C.,Snodgrass, C.,Finet, F.,Furusawa, K IOP Publishing 2011 The Astrophysical journal Vol.728 No.2

        <P>We report the gravitational microlensing discovery of a sub-Saturn mass planet, MOA-2009-BLG-319Lb, orbiting a K-or M-dwarf star in the inner Galactic disk or Galactic bulge. The high-cadence observations of the MOA-II survey discovered this microlensing event and enabled its identification as a high-magnification event approximately 24 hr prior to peak magnification. As a result, the planetary signal at the peak of this light curve was observed by 20 different telescopes, which is the largest number of telescopes to contribute to a planetary discovery to date. The microlensing model for this event indicates a planet-star mass ratio of q = (3.95 +/- 0.02) x 10(-4) and a separation of d = 0.97537 +/- 0.00007 in units of the Einstein radius. A Bayesian analysis based on the measured Einstein radius crossing time, t(E), and angular Einstein radius,theta(E), along with a standard Galactic model indicates a host star mass of M-L = 0.38(-0.18)(+0.34) M-circle dot and a planet mass of M-p = 50(-24)(+44)M(circle plus), which is half the mass of Saturn. This analysis also yields a planet-star three-dimensional separation of a = 2.4(-0.6)(+1.2) AU and a distance to the planetary system of D-L = 6.1(-1.2)(+1.1) kpc. This separation is similar to 2 times the distance of the snow line, a separation similar to most of the other planets discovered by microlensing.</P>

      • KCI등재

        A CLASS OF MAPPINGS BETWEEN R<sub>z</sub>-SUPERCONTINUOUS FUNCTIONS AND R<sub>δ</sub>-SUPERCONTINUOUS FUNCTIONS

        Prasannan, A.R.,Aggarwal, Jeetendra,Das, A.K.,Biswas, Jayanta The Honam Mathematical Society 2017 호남수학학술지 Vol.39 No.4

        A new class of functions called $R_{\theta}$-supercontinuous functions is introduced. Their basic properties are studied and their place in the hierarchy of strong variants of continuity, which already exist in the literature, is elaborated. The class of $R_{\theta}$-supercontinuous functions properly contains the class of $R_z$-supercontinuous functions [39] which in turn properly contains the class of $R_{cl}$-supercontinuous functions [43] and so includes all cl-supercontinuous (clopen continuous) functions ([38], [34]) and is properly contained in the class of $R_{\delta}$-supercontinuous functions [24].

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        Photoproduction of the<sub>f1</sub>(1285)meson

        Dickson, R.,Schumacher, R. A.,Adhikari, K. P.,Akbar, Z.,Amaryan, M. J.,Anefalos Pereira, S.,Badui, R. A.,Ball, J.,Battaglieri, M.,Batourine, V.,Bedlinskiy, I.,Biselli, A.,Boiarinov, S.,Briscoe, W. J. American Physical Society 2016 Physical Review C Vol.93 No.6

        <P>The f(1)(1285) meson withmass 1281.0 +/- 0.8MeV/c(2) and width 18.4 +/- 1.4MeV (full width at half maximum) was measured for the first time in photoproduction from a proton target using CLAS at Jefferson Lab. Differential cross sections were obtained via the eta pi(+)pi(-), K+(K) over bar (0) pi(-), and (K-K0)pi(+) decay channels from threshold up to a center-of-mass energy of 2.8 GeV. The mass, width, and an amplitude analysis of the eta pi(+)pi(-) final-state Dalitz distribution are consistent with the axial-vector J(P) = 1(+) f(1)(1285) identity, rather than the pseudoscalar 0(-) eta(1295). The production mechanism is more consistent with s-channel decay of a high-mass N* state and not with t-channel meson exchange. Decays to eta pi pi go dominantly via the intermediate a(0)(+/-) (980)pi(-/+) states, with the branching ratio Gamma [a(0)pi (no (K) over barK)]/Gamma[eta pi pi (all)] = 0.74 +/- 0.09. The branching ratios Gamma (K (K) over bar pi)/Gamma(eta pi pi) = 0.216 +/- 0.033 and Gamma (gamma rho(0))/Gamma(eta pi pi) = 0.047 +/- 0.018 were also obtained. The first is in agreement with previous data for the f(1)(1285), while the latter is lower than the world average.</P>

      • MOA-2010-BLG-073L: AN M-DWARF WITH A SUBSTELLAR COMPANION AT THE PLANET/BROWN DWARF BOUNDARY

        Street, R. A.,Choi, J.-Y.,Tsapras, Y.,Han, C.,Furusawa, K.,Hundertmark, M.,Gould, A.,Sumi, T.,Bond, I. A.,Wouters, D.,Zellem, R.,Udalski, A.,Snodgrass, C.,Horne, K.,Dominik, M.,Browne, P.,Kains, N.,Br IOP Publishing 2013 The Astrophysical journal Vol.763 No.1

        <P>We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010 March 18. This event was remarkable because the source was previously known to be photometrically variable. Analyzing the pre-event source light curve, we demonstrate that it is an irregular variable over timescales >200 days. Its dereddened color, (V - I)(S),(0), is 1.221 +/- 0.051 mag, and from our lens model we derive a source radius of 14.7 +/- 1.3 R-circle dot, suggesting that it is a red giant star. We initially explored a number of purely microlensing models for the event but found a residual gradient in the data taken prior to and after the event. This is likely to be due to the variability of the source rather than part of the lensing event, so we incorporated a slope parameter in our model in order to derive the true parameters of the lensing system. We find that the lensing system has a mass ratio of q = 0.0654 +/- 0.0006. The Einstein crossing time of the event, t(E) = 44.3 +/- 0.1 days, was sufficiently long that the light curve exhibited parallax effects. In addition, the source trajectory relative to the large caustic structure allowed the orbital motion of the lens system to be detected. Combining the parallax with the Einstein radius, we were able to derive the distance to the lens, D-L = 2.8 +/- 0.4 kpc, and the masses of the lensing objects. The primary of the lens is an M-dwarf with M-L,M-1 = 0.16 +/- 0.03 M-circle dot, while the companion has M-L,M-2 = 11.0 +/- 2.0 M-J, putting it in the boundary zone between planets and brown dwarfs.</P>

      • Enhanced production of nargenicin A1 and creation of a novel derivative using a synthetic biology platform

        Dhakal, D.,Chaudhary, A. K.,Yi, J. S.,Pokhrel, A. R.,Shrestha, B.,Parajuli, P.,Shrestha, A.,Yamaguchi, T.,Jung, H. J.,Kim, S. Y. Springer Science + Business Media 2016 Applied microbiology and biotechnology Vol.100 No.23

        <P>Nargenicin A1, an antibacterial produced by Nocardia sp. CS682 (KCTC 11297BP), demonstrates effective activity against various Gram-positive bacteria. Hence, we attempted to enhance nargenicin A1 production by utilizing the cumulative effect of synthetic biology, metabolic engineering and statistical media optimization strategies. To facilitate the modular assembly of multiple genes for genetic engineering in Nocardia sp. CS682, we constructed a set of multi-monocistronic vectors, pNV18L1 and pNV18L2 containing hybrid promoter (derived from ermE* and promoter region of neo (r) ), ribosome binding sites (RBS), and restriction sites for cloning, so that each cloned gene was under its own promoter and RBS. The multi-monocistronic vector, pNV18L2 containing transcriptional terminator showed better efficiency in reporter gene assay. Thus, multiple genes involved in the biogenesis of pyrrole moiety (ngnN2, ngnN3, ngnN4, and ngnN5 from Nocardia sp. CS682), glucose utilization (glf and glk from Zymomonas mobilis), and malonyl-CoA synthesis (accA2 and accBE from Streptomyces coelicolor A3 (2)), were cloned in pNV18L2. Further statistical optimization of specific precursors (proline and glucose) and their feeding time led to similar to 84.9 mg/L nargenicin from Nocardia sp. GAP, which is similar to 24-fold higher than Nocardia sp. CS682 (without feeding). Furthermore, pikC from Streptomyces venezuelae was expressed to generate Nocardia sp. PikC. Nargenicin A1 acid was characterized as novel derivative of nargenicin A1 produced from Nocardia sp. PikC by mass spectrometry (MS) and nuclear magnetic resonance (NMR) analyses. We also performed comparative analysis of the anticancer and antibacterial activities of nargenicin A1 and nargenicin A1 acid, which showed a reduction in antibacterial potential for nargenicin A1 acid. Thus, the development of an efficient synthetic biological platform provided new avenues for enhancing or structurally diversifying nargenicin A1 by means of pathway designing and engineering.</P>

      • SCISCIESCOPUS

        Analysis method for determination of nisin A and nisin Z in cow milk by using liquid chromatography-tandem mass spectrometry

        Ko, K.Y.,Park, S.R.,Lee, C.A.,Kim, M. American Dairy Science Association 2015 Journal of dairy science Vol.98 No.3

        Nisin, a polypeptide with antimicrobial properties, is known as a natural preservative. It is used in various foods, including dairy products. This study validated a novel procedure using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of nisin A and nisin Z in cow milk. An extraction solution of 0.1 M acetate buffer containing 1 M NaCl (pH 2.0) and MeOH (1:1) was used to extract nisin A and nisin Z from milk samples. After the addition of extraction buffers, the samples were homogenized and centrifuged. The supernatant was filtered and injected for LC-MS/MS analysis. The linearity of the analytical method had a high correlation coefficient (r≥0.9987). The limits of quantitation of nisin A and nisin Z were approximately 12.9 and 10.9 @?g/kg, respectively. The accuracy of the analytical method in milk ranged from 90.6 to 103.4% for nisin A and from 83.8 to 104.4% for nisin Z. The coefficient of variation values of intra- and interday in milk determined to be less than 5% in both nisin A and nisin Z. Because the proposed method has comparatively high recovery and low coefficient of variation, it seems appropriate for the determination of nisin A and nisin Z in milk samples. As the quantification of nisin A and nisin Z in milk samples by using LC-MS/MS has only been rarely reported until now, this study provides a meaningful technological advance for the dairy industry.

      • KCI등재

        Salinity Tolerance of Blackgram and Mungbean 2 : Mineral Ions Accumulation in Different Plant Parts

        P. K. Raptan,A. Hamid,Q. A. Khaliq,A. R. M. Solaiman,J. U. Ahmed,M. A. Karim 韓國作物學會 2001 Korean journal of crop science Vol.46 No.5

        Blackgram (Vigna mungo) is more salt tolerant than mungbean (Vigna radiata). This study was initiated to know whether the accumulation pattern of mineral ions in different plant parts plays a significant role in the differences in salt tolerance between the two Vigna species. Different mineral ions, viz. N, Cl, Na, K, Mg and Ca in different organs of two varieties of each of blackgram- Barimash-l (susceptible one) and Barimash-2 (tolerant one), and mungbean-Barimung-3 (tolerant one) and Barimung-4(susceptible one), were analyzed after growing with 0, 50, 75 and 100 mM NaCl solutions. The two crops showed a decreased but similar pattern of total N accumulation under saline conditions. The tolerant variety of both the crops showed a less reduction in total N than the susceptible one. Leaves showed the maximum while stem the minimum N, irrespective of levels of salinity. C l[-10] and N a+ accumulation increased with the increasing salinity levels. Interestingly, similar to a halophyte, the salt tolerant blackgram exhibited conspicuously higher amount of N a+ in the shoot than the salt-susceptible mungbean. However, the tolerant varieties showed less amount of N a+ than the susceptible one, especially in blackgram. Seeds of both Vigna spp. accumulated the minimum amount of N a+ than other plant parts. K+ accumulation decreased by salinity in most of the plant parts, except seeds. Blackgram showed larger reduction in K than mungbean. The Mg++ increased in leaves, petioles and stem by salinity while decreased in the roots, podshells and seeds in both the crops. Salinity increased Ca++ accumulation in all plant-parts except roots of both Vigna spp. Apparently, the leaves of mungbean accumulated higher concentration of Ca++ than blackgram. Varietal differences in the accumulation pattern of K+ , Mg++ and Ca++ were not clear. It was concluded that blackgram, presumably, possesses a similar salt tolerance mechanism to halophyte, and the pattern of accumulation of mineral ions in blackgram and mungbean was not fully ascribed to the differences in salinity tolerance between the two Vigna species.gna species.ies.s.ies.

      • Mouse Pulmonary Cytochrome P-450 Naphthalene Hydroxylase : cDNA Cloning, Sequence, and Expression in Saccharomyces cerevisiae

        Ritter, Joseph K.,Owens, Ida S.,Negishi, Masahiko,Nagata, Kiyoshi,Sheen, Yhun Y.,Gillette, James R.,Sasame, Henry A. 이화여자대학교 생명과학연구소 1991 생명과학연구논문집 Vol.2 No.-

        We have isolated a cDNA clone, Nah-2, encoding the cytochrome P-450^Nah(naphthalene hydroxylase) from a mouse lung λZAP cDNA library using anti-cytochrome P-450^Nah IgG as a probe. This same antibody selectively blocked[Nagata, K.,Martin, B. M., Gillette, J. R., & Sasame, H. A.(1990) Drug Metab. Dispos. 18, 557-564] the cytochrome P-450 in mouse lung microsomes that catalyzed the conversion of naphthalene to (1R,2S)- naphthalene 1,2-oxide, which has been postulated as a causative agent in the naphthalene-induced tissue-specific necrosis of Clara cells in mouse lung. The toxic effect is seen in mouse and not in rat. The cDNA encodes a polypeptide of 491 amino acids with a molecular mass of 50 kDa. Northern blot analysis with an Nah-2specific probe revealed that the mRNA is expressed in a species-and tissue-specific manner, present only in mouse lung and liver and not in that of rat. The mRNA encoding Nah-2 is constitutively expressed and is not induced by either phenobarbital, pyrazole, pregnenolone 16∂-carbonitrile, or 3-methylcholanthrene. Comparative amino acid sequence analyses with other documented members of the P-450 gene superfamily revealed that this encoded protein is in the IIF subfamily. To analyze its substrate specificity, the cDNA was inserted into the vector, pAAH5, and expressed in the Saccharonyces cerevisiae strain, AH_22. The presence of cytochrome P-450_Nah in the micreosomes isolated from transformed cell and analyzed by Western blot was confirmed by immunocomplexing product with anti-cytochrome P450_Nah IgG. Furthermore, activity toward naphthalene in the microsomes from the transformed cells established that this clone encodes a naphthalene hydroxylase. Like lung microsomes and purified and reconstituted cytochrome P450_Nah, transformed yeast microsomes convert naphthalene primarily to the trans-(1R)-hydroxy-(2R)-glutathionyl-1, 2-dihydronaphthalene conjugate, a stable form of the putative toxicant(1R,2S) oxide in the presence of glutathione and a mixture of glutathione S-transferases. Results of immunochemical studies support a role of this cytochrome P-450 in lung toxicity in mice exposed to high doses of naphthalene.

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        Critical temperature switch development for metallic magnetic calorimeters

        Kim, S R,Jeon, J A,Kim, I,Kim, H L,Kim, S G,Kwon, D H,Lee, M K,Lee, H J,Kim, Y H IOP Publishing Ltd 2019 Superconductor science & technology Vol.32 No.5

        <P>We report the recent progress on critical temperature switch development for metallic magnetic calorimeters (MMCs). The superconducting planar coil of a micro-fabricated MMC is charged with a persistent current, which serves as the stable field current to magnetize the sensor material. Part of the Nb superconducting circuit is fabricated with an alloy of Nb and Ta (NbTa), another superconducting material with a transition temperature (<I>T</I> <SUB> <I>C</I> </SUB>) that is lower than that of Nb. A persistent current can be injected into the loop while lowering the temperature from above to below the <I>T</I> <SUB> <I>C</I> </SUB> of the NbTa switch. Resistance measurements of a sputtered film of a NbTa alloy with a Ta concentration of 62% showed a clear superconducting transition at 5.29 K. Using one of the completed MMC devices, the ability to use the <I>T</I> <SUB> <I>C</I> </SUB> switch for charging with a persistent current up to 120?mA was tested by means of magnetization measurements. The magnetization measurements recorded with a DC-SQUID were in good agreement with the calculated values in all tested cases with four different currents. These results indicate that an MMC can be charged with a persistent current as expected using the <I>T</I> <SUB> <I>C</I> </SUB> switch. This work is the first demonstration of the proposed <I>T</I> <SUB> <I>C</I> </SUB> switch in a complete MMC setup. Based on the present progress, future studies will investigate multi-channel operation and the development of a hybrid setup with an on-chip heater.</P>

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        Novel anti-apoptotic mechanism of A20 through targeting ASK1 to suppress TNF-induced JNK activation

        Won, M,Park, K A,Byun, H S,Sohn, K-C,Kim, Y-R,Jeon, J,Hong, J H,Park, J,Seok, J H,Kim, J M,Yoon, W-H,Jang, I-S,Shen, H M,Liu, Z G,Hur, G M Macmillan Publishers Limited 2010 CELL DEATH AND DIFFERENTIATION Vol.17 No.12

        The zinc-finger protein A20 has crucial physiological functions as a dual inhibitor of nuclear factor-κB (NF-κB) activation and apoptosis in tumor necrosis factor (TNF) receptor 1 signaling pathway. Although the molecular basis for the anti-NF-κB function of A20 has been well elucidated, the anti-apoptotic function of A20 is largely unknown. Here, we report a novel mechanism underlying the anti-apoptotic function of A20: A20 blocks TNF-induced apoptosis through suppression of c-jun N-terminal kinase (JNK) by targeting apoptosis signal-regulating kinase1 (ASK1). First, the ectopic expression of A20 drastically inhibits TNF-induced JNK activation and apoptosis in multiple cell types including those deficient of NF-κB activation. Unexpectedly, the blunting effect of A20 on TNF-induced JNK activation is not mediated by affecting the TNFR1 signaling complex formation. Instead, A20 interacts with ASK1, an important MAPKK kinase in the JNK signaling cascade. More importantly, overexpression of wild-type A20, but not of mutant A20 (ZnF4; C624A, C627A), promotes degradation of the ASK1 through the ubiquitin-proteasome system. Taken together, the results from this study reveal a novel anti-apoptotic mechanism of A20 in TNF signaling pathway: A20 binds to ASK1 and mediates ASK1 degradation, leading to suppression of JNK activation and eventually blockage of apoptosis.

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