Abstract— A visual pigment was extracted from lamprey retina and was expressed in cultured mammalian cells (293S) using a cDNA fragment isolated from lamprey retina. The extracted pigment, a putative lamprey rhodopsin, had an absorption maximum at 503 nm. The recombinant lamprey rhodopsin, reconstituted with 11- cis -retinal, showed an absorption maximum at about 500 nm. Both pigments reacted with an anti-bovine rhodopsin antibody (Rh29), which recognizes the short photoreceptor cells in lamprey retina. Unlike rhodopsins of higher vertebrates, the lamprey rhodopsin bleached gradually in the presence of 100 m M hydroxylamine even in the dark. Our results suggest that, despite its high similarities with other vertebrate rhodopsins, lamprey rhodopsin has a character different from those of higher vertebrates. 相似文献
We calculated the molecular field coefficients, nFeFe and nRFe (R=Sm, Gd, Tb, Ho and Tm), for R2Fe17−xGax and the values of nFeFe and nSmFe for R2Fe17−xTx (T=Al and Si) using the experimental values of the Curie temperature. The values of nFeFe increase in spite of the decrease of μFe for 0?x?5. The values of nSmFe have large values when the magnetic anisotropy is axial. For 6?x?8, the values of nFeFe, nHoFe and nTmFe increase largely, which is related to the change of the easy magnetization direction. For Y2Fe17−xTx (T=Ga and Al), the values of nFeFe have a maximum value with increasing those of μFe. With increasing V−1, the values of nFeFe have a maximum value around the same value of V−1 for Y2Fe17−xTx (T=Ga and Al). For Y2Fe17−xSix, the values of nFeFe increase with increasing V−1. 相似文献
N-Tosylaziridine was found to be a useful substrate for cycloaddition reaction with carbon dioxide. The reaction was successfully catalyzed by lithium bromide under atmospheric pressure to give the corresponding five-membered cyclic urethane, N-tosyl-1,3-oxazolidin-2-one, selectively. It was found that electron-donating nature of the substituent at 2-position of N-tosylaziridine accelerated the reaction, and this tendency allowed us to estimate the reaction mechanism. 相似文献
The volume changes for each step in the successive complex formation between the metal ions Cu2+ and Zn2+ with the ligand L, where L is bpy = 2,2-bipyridine and phen = 1,10-phenanthroline, in water have been determined at 25°C in the following way: Aqueous solution of M(NO3)2 has been taken as solvent and the densities of solutions have been measured at various ratio of [ligand]/[M2+]. The partial molar volumes V
20
have been calculated for the nitrates of the complex ions [ML]2+, [ML2]2+, and [ML3]2+. The volume change V is given as V=V
20
([MLn+1](NO3)2)–V
20
([MLn](NO3)2)–V
20
(L). Volume changes of the first coordination of L to M2+ are larger than the other two steps and the third step coordination leads to small or even negative values of V. 相似文献
The magnetic properties of Y2Fe17−xGax for 3≤x≤7 and Gd2Fe17−xGax for 5≤x≤7 have been investigated using 57Fe Mössbauer spectroscopy. These compounds have the rhombohedral Th2Zn17 structure. X-ray diffraction analysis of aligned powders shows that the easy direction of magnetization is parallel to the c-axis in Y2Fe10Ga7 and Gd2Fe10Ga7 and is perpendicular to the c-axis in Y2Fe14Ga3, Y2Fe12Ga5, Gd2Fe12Ga5 and Gd2Fe11Ga6. Mössbauer studies indicate that those samples are ordered ferromagnetically. The 57Fe hyperfine field decreases with increasing Ga content. This decrease results from the decreased magnetic exchange interactions resulting from Ga substitution. The average isomer shift, δ, for R2Fe17−xGax (R=Y and Gd) at room temperature is positive and the magnitude of δ increases with increasing Ga content. 相似文献
Growth modes of Co thin films on the both N-saturated and partially N-adsorbed Cu(0 0 1) surfaces are studied in detail. From results of the STM and XPS measurements, segregation of N atoms depending on the Co island size is concluded. This new type of atom segregation is explained by means of a lattice strain of the substrate due to the small Co island formation. A novel core-level shift of N 1s during the Co film growth is also reported. A possible influence of the lattice strain to the electronic structure of the surfactant is discussed. 相似文献
We present the design of a novel metal micro-aperture surface emitting laser for tera byte optical data storage. The field distribution near micro-aperture is calculated by 2-dimensional finite element method, and it is shown that a spot size as narrow as 100 nm beyond a diffraction limit is obtainable. 相似文献
Summary: A diastereomeric pair of novel N‐propargylphosphonamidates, HCCCH2NHP(O)(CH3)O‐L ‐menthyl was synthesized by the successive condensations of methylphosphonic dichloride with L ‐menthol and propargylamine. The (R)‐P‐isomer ( 1a ) was isolated, and the absolute configuration was determined by XRD. Polymerization of 1a , and a mixture of 1a and (S)‐P‐isomer ( 1b ) was carried out with a zwitterionic Rh complex as a catalyst. cis‐Stereoregular polymers with number‐average molecular weights of 5 600–9 800 were obtained in good yields. Poly( 1a ) and poly( 1a 29‐co‐ 1b 71) exhibited large specific rotations (+408 and −146°), and intense Cotton effects ([θ] = +2.25 and −0.9 × 104 deg · cm2 · dmol−1) based on the conjugated polyacetylene backbone around 325 nm in CHCl3, indicating that these polymers have helical structures, whose predominant helical senses are opposite.
Polymerization of N‐propargylphosphonamidate. 相似文献
Fluorogenic active host labeled at the upper and lower rims of -cyclodextrin, namely, mono-3A-deoxy-3A-pyrenebutylamido-6X-O-mono-pyrenebutylate-mono-altro--cyclodetrin (mixture-1,X = A, B, C, D, E, F, G, or H), has been synthesized in order to investigate their host-guest complexation with steroidal compoundsusing fluorescence spectra. Monomer and excimer fluorescence was observed for mixture host. Inclusion of a guest molecule in the cyclodextrin cavity resultedin increased monomer fluorescence and decreased excimer fluorescence. The extent of monomerand excimer fluorescence variations ofmixture-1 with the guestwas used as an indication for the sensing ability. The guest inducedfluorescence changes were measured for 10-7 M solutions of mixture-1.The values I/I0, where I0 and I are fluorescence intensities in the absence and presence of a guest, respectively, and I is I0 - I, were then used to describe the sensing ability. 相似文献