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201.
The sub-millisecond protonation dynamics of the chromophore in S65T mutant form of the green fluorescent protein (GFP) was
tracked after a rapid pH jump following laser-induced proton release from the caged photolabile compoundo-nitrobenzaldehyde. Following a jump in pH from 8 to 5 (which is achieved within 2 μs), the fluorescence of S65T GFP decreased
as a single exponential with a time constant of ∼90 μs. This decay is interpreted as the conversion of the deprotonated fluorescent
GFP chromophore to a protonated non-fluorescent species. The protonation kinetics showed dependence on the bulk viscosity
of the solvent, and therefore implicates bulk solvent-controlled protein dynamics in the protonation process. The protonation
is proposed to be a sequential process involving two steps: (a) proton transfer from solvent to the chromophore, and (b) internal
structural rearrangements to stabilize a protonated chromophore. The possible implications of these observations to protein
dynamics in general is discussed 相似文献
202.
203.
S. Schrader A. Penzkofer W. Holzer R. Velagapudi B. Grimm 《Journal of luminescence》2004,110(4):303-308
Optical, structural and morphological properties of thin films of polyparaphenylenevinylene (PPV) formed by an alkyl sulfinyl precursor route have been studied. Thin films were fabricated on an optical glass and on quartz glass either by spin-coating of the precursor solution or by layer-by-layer deposition using Langmuir–Blodgett technique. PPV precursor films were also spin-coated on gold-coated glass in order to study thin-film optical parameters by surface plasmon spectroscopy. We have been successful in forming about 40 precursor mono layers on quartz glass by Langmuir–Blodgett technique using optimized surface pressure and dipping conditions. After thermal conversion of the precursor layers good quality fluorescent PPV films of yellow colour have been obtained. Optical characterization of the films was carried out by linear absorption and emission spectroscopy, ellipsometry, and surface plasmon spectroscopy. Structural and morphological studies on the thin films were carried out by using X-ray scattering and atomic force microscopy. Wave-guided travelling-wave laser action has been achieved in a PPV film on quartz glass. The sample was transversally pumped with picosecond laser pulses (wavelength 347.15 nm, duration 35 ps). Laser emission occurred at 550 nm for pump pulse energy densities above . 相似文献
204.
V.B. Nalbandyan 《Journal of Physics and Chemistry of Solids》2004,65(6):1201
The irreproducibility of electrical properties of Na0.88Li0.12NbO3 solid solution on thermal cycling reported by M.A.L. Nobre and S. Lanfredi is explained by gradual decomposition of the supersaturated solid solution below ca. 800 °C. 相似文献
205.
A mathematical model of laser beam treatment of double layer alloys (Ni/Fe, Al/Fe and Cr/Fe systems) describing the effect of laser beam on different physical and geometrical parameters of coated layer system has been adapted. The numerical solutions of the non-homogeneous heat-transport differential equation could estimate the temperature of the treated region.The suggested model allows investigation of the temperature distribution as a function of treated surface and laser parameters. The physical parameters of the treated materials were taken as functions of temperature due to the change in the temperature of the treated double layer materials. 相似文献
206.
It is shown that the introduction of heavy inert gas impurities into the condensed phase of a lighter inert gas can significantly change the kinetic properties of the latter at high pressures. The electronic structure of the ordered Ar15Xe solid solution is calculated. Doping of the condensed phase of a light inert gas with atoms of a heavier inert gas may become a new convenient tool in high-pressure experiments. 相似文献
207.
S. B. Bushuk Yu. A. Kal'vinkovskaya A. N. Rubinov 《Journal of Applied Spectroscopy》2004,71(2):291-294
Capture of an ensemble of polymeric microspheres in a water suspension under the action of optical gradient forces in the field of interfering laser beams has been investigated for the case of two-, three-, and four-beam interference. The self-diffraction and diffraction of radiation on induced ordered spatial distribution of particles have been obtained. 相似文献
208.
We prove that every noetherian affine PI Hopf algebra has finite injective dimension, which answers a question of Brown (1998).
209.
In this article, we define stochastic dynamics for a system coupled to reservoirs. The rules for forward and backward transitions are related by a generalized detailed balance identity involving the system and its reservoirs. We compare the variation of information and of entropy. We define the Carnot dissipation and prove that it can be expressed in terms of cyclic transformations. Lower bounds for partial dissipations are also studied, as well as the effect of switching off certain reservoirs. We also study the near degeneracy of the stochastic matrix, relate it to phase transitions and we show that the reduced dynamics on the set of phases is a permutation. Finally, we relate these concepts to heat, work and more generally to the dissipation and creation of resources, in general systems. 相似文献
210.
M.B. Xu 《Applied Acoustics》2003,64(7):731-752
The forced vibration of an infinite elastic circular cylindrical shell filled with fluid is studied. Three methods are employed to analyze the forced vibration problem of this shell-fluid coupled system, that is, wave propagation approach (wave mode superposition), theorem of residues and a numerical integral method. In order to explain these methods more explicitly, before being used to investigate the vibration of an infinite fluid-filled elastic circular cylindrical shell, all these three methods are employed firstly to analyze the forced vibration problem of an infinite beam and an infinite elastic circular cylindrical shell in vacuo. Advantage and disadvantage of these three methods are discussed and their interesting relationship is revealed. That is, to any circumferential wavenumber and frequency of the external force, there is an unchangeable relationship between the general coordinates of various waves in the wave propagation approach and the residuals in the theorem of residues. 相似文献