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101.
A biosensor for peptide determination was constructed with trypsin or α-chymotrypsin immobilized on hydrogen ion-selective coated-wire electrode and its fundamental properties were investigated with two artificial peptides. The substrates could be determined in the range 0.1–40 mM with response times of 5–10 min. The effects of pH and concentration of buffer solution on the determination were investigated. 相似文献
102.
Kotaro Nagatani Yunosuke Hoshino Haruka Tezuka Masahisa Nakada 《Tetrahedron letters》2017,58(10):959-962
A synthetic pathway to the C-ring fragment of cotylenin A which emerged from our retrosynthetic analysis of cotylenin A is described. The catalytic asymmetric intramolecular cyclopropanation (CAIMCP) of the α-diazo-β-keto ester bearing 2,4,6-trimethylphenyl group as the ester part has been found to afford the crystalline product with high ee, which allowed to establish the approach to the C-ring fragment which required ten-pot operations. The developed approach would be beneficial to a large scale synthesis of the C-ring fragment for the total synthesis of cotylenin A. 相似文献
103.
The pseudoplastic flow of suspensions, alumina or styrene-acrylamide copolymer particles in water or an aqueous solution of glycerin has been studied by the step-shear-rate method. The relation between the shear rate,D, and the shear stress,, in the step-shear-rate measurements, where the state of dispersion was considered to be constant, was expressed as = AD
1/2 +CD. The effective solid volume fraction,ø
F, andA were dependent on the shear rate and expressed byø
F =aD
b andA = D
. Combining the above relations, the steady flow curve was expressed by = D
1/2 + +
0 (1 – a D
b/0.74)–1.85
D, where
0 is the viscosity of the medium.With an increase in solid volume fraction and a decreases in the absolute value of the-potential, the flow behavior of the suspensions changed from Newtonian ( = = b = 0), slightly pseudoplastic ( = b = 0), pseudoplastic ( = 0) to a Bingham-like behavior.The change in viscosity of the medium had an effect on the change in the effective volume fraction. 相似文献
104.
105.
Sakakura A Hori M Fushimi M Ishihara K 《Journal of the American Chemical Society》2010,132(44):15550-15552
A chiral copper(II) complex of 3-(2-naphthyl)-l-alanine amide successfully catalyzes the enantioselective 1,3-dipolar cycloaddition reaction of nitrones with propioloylpyrazole and acryloylpyrazole derivatives. The asymmetric environment created by intramolecular π-cation interaction gives the corresponding adducts in high yields with excellent enantioselectivity. This is the first successful method for the catalytic enantioselective 1,3-dipolar cycloaddition of nitrones with acetylene derivatives. The 1,3-dipolar cycloadducts can be stereoselectively converted to β-lactams via reductive cleavage of the N-O bond using SmI(2). 相似文献
106.
To evaluate the superiority of using a task-specific onium salt (TSOS), a novel TSOS reagent 1-methyl-3-[2-(8-quinolinylaminosulfonyl)ethyl]imidazolium chloride (HmimesqCl) was synthesized, and its performance in extraction of different divalent metal cations was investigated. This TSOS reagent has both a cationic imidazolium unit and an anionic (proton-dissociable) complexation unit for the extraction of metal cations into an ionic liquid. In the use of HmimesqCl, relatively high extraction of metals resulted in comparison with the use of its non-imidazolium analogs, without changing the extraction selectivity. 相似文献
107.
A photoinduced spin-state change in the itinerant correlated electron system is studied. A photon introduced in the low-spin band insulator induces a bound state of the high-spin state and a photoexcited hole. This bound state brings a characteristic peak in the pump-probe optical absorption spectra which are completely different from the spectra in thermal-excited states. The present results well explain the recent experiments of the ultrafast optical spectroscopy in perovskite cobaltites. 相似文献
108.
The visible second harmonic of the idler output from a noncollinear optical parametric amplifier was compressed using adaptive dispersion control with a deformable mirror. The amplifier was pumped by and seeded in the signal path by a common 400 nm second-harmonic pulse from a Ti:sapphire regenerative amplifier. Thus, both the idler output and the second harmonic of the idler were passively carrier-envelope phase stabilized. The shortest pulse duration achieved was below 3 fs. 相似文献
109.
A convenient synthesis of chiral 3,3′-disubstituted 1,1′-binaphthyl-2,2′-disulfonic acids (BINSA, 1) was developed. The key was directed ortho-lithiation of BINSA methyl ester 2 with n-BuLi and subsequent reaction with an electrophile. Electrophiles such as Br2, I2, Me3SiOTf, and i-PrOB(Pin) reacted smoothly with 3,3′-dilithiated BINSA methyl ester, and the corresponding 3,3′-dihalo-, 3,3′-bis(trimethylsilyl)-, and 3,3′-diboryl-BINSA derivatives were obtained in yields of 21–78%. This simple synthetic method is highly attractive since the ability to prepare 3,3′-disubstituted BINOLs in advance can be useful. 相似文献
110.
We have developed efficient electrocatalysts for methanol oxidation using new synthetic method facilitating deposition of Pt–Ru very thin nanoplatelets on carbon nanoparticles The method involves oxidation of carbon support, adsorption of Pb2+, its reduction and galvanic displacement of Pb0 by Pt and/or Ru. The Pt mass activity of this catalyst is about 10 times higher than that of the commercial Pt–Ru/C. The catalyst with the 1:1 Pt/Ru ratio displayed the highest methanol oxidation activity per surface Pt atom. Our results demonstrate the new synthetic method that yields the catalyst with potential for solving the problem of high Pt loading in direct methanol fuel cell anodes. 相似文献