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41.
42.
Tatsuo Iwasa Fumio Tokunaga Tôru Yoshizawa Thomas G. Ebrey 《Photochemistry and photobiology》1980,31(1):83-85
Abstract— Quantum efficiencies for photoconversion of bacteriorhodopsin (trans-bR) to a bathochromic product (batho-bRt ) and its photoreversion in purple membrane at 77 and 9 K were investigated with low temperature spectrophotometry. The kinetics of the photoconversion and its photoreversion cannot be expressed by a single exponential curve. The photoconversions at 77 and 9 K showed the same slope in the early stage. The kinetics of the photoreversions were identical at the two temperatures. These results indicate that the quantum efficiencies for the conversion of trans-bR to batho-bRt or for its photoreversion are identical at the two temperatures.
The fact that the photoreversion cannot be expressed by a single exponential curve suggests the existence of several conformational states of batho-bRt due to the trimer structure of the purple membrane. 相似文献
The fact that the photoreversion cannot be expressed by a single exponential curve suggests the existence of several conformational states of batho-bR
43.
The quantum oscillations in the AC magnetoconductance was studied for inversion layers in Si-MOS-FETs under high magnetic fields at 1.5 K. Each peak in the Shubnikov-de Haas oscillation was found to be remarkably sharpened with increasing frequency up to 50 MHz. It was also found that the width of the gate voltage for non-conductive region (σxx=0) increases with increasing frequency. 相似文献
44.
Specific heat has been investigated in a layered nitride superconductor, Li(0.12)ZrNCl, with T(c)=12.7 K. The obtained data have shown a marked dichotomy: The specific heat jump at T(c) (DeltaC/gamma(n)T(c)=1.8) and the superconducting gap ratio (2Delta/k(B)T(c)=4.6-5.2) have indicated an intermediate to a strong coupling of electrons, while the upper limit of the electron-phonon coupling constant lambda has directly been estimated to be 0.22, which belongs to a weak coupling regime. Furthermore, the rapid increase of gamma as a function of magnetic field suggests that the present material has an anisotropic s wave gap. 相似文献
45.
Li J Zhang ZP Schwartz AJ Abe K Abe K Aihara H Akatsu M Asano Y Aushev T Bakich AM Bay A Bedny I Bitenc U Bizjak I Bondar A Bozek A Bracko M Brodzicka J Browder TE Chao Y Chen A Chen KF Chen WT Cheon BG Chistov R Choi SK Choi Y Chuvikov A Cole S Dalseno J Danilov M Dash M Dong LY Drutskoy A Eidelman S Eiges V Enari Y Fang F Fratina S Gabyshev N Garmash A Gershon T Gokhroo G Haba J Hayasaka K Hayashii H Hazumi M Higuchi T Hokuue T Hoshi H Hou S Hou WS Iijima T Imoto A Inami K Itoh R Iwasaki M 《Physical review letters》2005,94(7):071801
We have searched for mixing in the D(0)-D (0) system by measuring the decay-time distribution of D(0) --> K(+) pi(-) decays. The analysis uses 90 fb(-1) of data collected by the Belle detector at the KEKB e(+) e(-) collider. We fit the decay-time distribution for the mixing parameters x' and y' and also for the parameter R(D), which is the ratio of the rate for the doubly-Cabibbo-suppressed decay D(0)--> K+ pi(-) to that for the Cabibbo-favored decay D(0)--> K-pi(+). We do these fits both assuming CP conservation and allowing for CP violation. We use a frequentist method to obtain a 95% C.L. region in the x'(2) - y' plane. Assuming no mixing, we measure R(D) = (0.381 +/- 0.017(+0.008)(-0.016))%. 相似文献
46.
Karataev P Araki S Hamatsu R Hayano H Muto T Naumenko G Potylitsyn A Terunuma N Urakawa J 《Physical review letters》2004,93(24):244802
An experiment on the investigation of optical diffraction radiation (ODR) from a slit target as a possible tool for noninvasive electron beam-size diagnostics has been performed at the KEK accelerator test facility. The experimental setup has been installed at the diagnostics section of the extraction line. We have performed the first incoherent ODR observation from a slit target. The measured angular distributions are in reasonable agreement with the theoretical expectation. The beam-size effect onto the ODR angular pattern has been observed. Moreover, the sensitivity to the beam size as small as 14 microm has been achieved. 相似文献
47.
Takada K Uehara T Nakao Y Matsunaga S van Soest RW Fusetani N 《Journal of the American Chemical Society》2004,126(1):187-193
Three new alpha-glucosidase inhibitors, schulzeines A-C (1-3), were isolated from the marine sponge Penares schulzei. Their structures were elucidated by spectral analysis and chemical degradations to be the isoquinoline alkaloids, encompassing two amino acids, and C(28) fatty acid, the last of which was sulfated. Absolute stereochemistry of schulzeines was determined by application of the modified Mosher analysis to fragments obtained by chemical degradation. Schulzeines A-C inhibit alpha-glucosidase with IC(50) values of 48-170 nM. 相似文献
48.
Itaka K Kanayama N Nishiyama N Jang WD Yamasaki Y Nakamura K Kawaguchi H Kataoka K 《Journal of the American Chemical Society》2004,126(42):13612-13613
An siRNA nanocarrier formed through self-assembly of PEG-based block catiomer possessing two distinct amino groups with different pKa values in a side chain was developed. This design provided the carrier with a sufficient siRNA complexation and an assumed buffering capacity in the endosomes, allowing it to exhibit remarkable gene knockdown abilities as well as sufficient serum tolerability. 相似文献
49.
Although some reactions on rotaxanes have been reported, the characteristic features of the rotaxanes providing unique reaction fields have hardly been studied, especially as catalyst. In our continuous studies on interlocked molecules such as rotaxanes and catenanes, we have noticed the importance of such interlocked structures with high freedom in functionalized materials such as molecular catalyst. For catalytic asymmetric benzoin condensations, two optically active rotaxanes possessing thiazolium salt moieties were prepared using the binaphthyl group as the chiral auxiliary. The benzoin condensations of aromatic aldehydes catalyzed by the chiral rotaxanes as catalysts gave optically active benzoins with ca. 30% ee in moderate to high chemical yields depending upon the structure of rotaxane and the reaction conditions employed. From the results, two intrarotaxane chirality transfers are confirmed: (i) through-space chirality transfer from wheel to axle and (ii) through-bond chirality transfer controlled with an achiral wheel. Because these asymmetric reaction fields are specific to the rotaxane structure, the importance and possibility of the "rotaxane field" as a particular reaction field is demonstrated in this work. 相似文献
50.
A rotaxane with a ferrocene moiety at the axle terminus was prepared. The redox potential of the ferrocene moiety decreased by ca. 80 mV when the rotaxane had a crown ether wheel capable of moving on the axle. Thus, the stabilization of the oxidized state of the ferrocene moiety is assumed to accompany the transposition of the wheel component on the axle toward the ferrocene moiety. [reaction--see text] 相似文献