A subclass of fluorescent proteins (FPs), large Stokes shift (LSS) FP, are characterized by increased spread between excitation and emission maxima. We report a photoswitchable variant of a red FP with an LSS, PSLSSmKate, which initially exhibits excitation and emission at 445 and 622 nm, but violet irradiation photoswitches PSLSSmKate into a common red form with excitation and emission at 573 ...

Experimental and theoretical investigations were performed to investigate the effect of water on optical properties of nanoceria as a function of Ce(3+) concentration. Theoretical studies based on density functional plane-wave calculations reveal that the indirect optical transitions in bare ceria nanoparticles are red-shifted with an increase in the concentration of Ce(3+). However, ceria nano...

In the Purkinje shift, the dark adapted eye becomes more sensitive to blue than to red as the retinal rods take over from the cones. A striking demonstration of the Purkinje shift, suitable for classroom use, is described in which a small change in viewing distance can reverse the perceived direction of a rotating annulus. We measured this shift with a minimum-motion stimulus (Anstis & Cavanagh...

The combined time-dependent density functional theory effective fragment potential method (TDDFT/EFP1) is applied to a study of the solvent-induced shift of the lowest singlet π → π* charge-transfer excited state of p-nitroaniline (pNA) from the gas to the condensed phase in water. Molecular dynamics simulations of pNA with 150 EFP1 water molecules are used to model the condensed-phase and gene...

We consider an effect generated by the nonexponential behavior of the survival amplitude of an unstable state in the long time region: In 1957 Khalfin proved that this amplitude tends to zero as t goes to the infinity more slowly than any exponential function of t. This effect can be described in terms of time-dependent decay rate γ(t) and then the Khalfin result means that this γ(t) is not a c...

Two-photon microscopy has advanced fluorescence imaging of cellular processes in living animals. Fluorescent proteins in the blue-green wavelength range are widely used in two-photon microscopy; however, the use of red fluorescent proteins is limited by the low power output of Ti-Sapphire lasers above 1,000 nm. To overcome this limitation we have developed two red fluorescent proteins, LSS-mKat...

This article investigates the interaction of a spherically symmetric massless scalar field with a strong gravitational field. It focuses on the propagation of waves in regions outside any horizons. The two factors acting on the waves can be identified as a redshift and a backscattering. The influence of backscattering on the intensity of the outgoing radiation is studied and rigorous quantitati...

in this work, we report, optical properties of cd1-xsnxte quantum dots (x= 0.05, 0.10 and 0.15) synthesized in water using thioglycolic acid (tga) as a modifier agent. the optical characterization of the samples was performed through absorption (uv) and photoluminescence spectra (pl). a red shift absorption and fluorescent emission peaks was observed which can be related to the increase of nano...

The tenth anniversary in 1999 of the fall of the Berlin Wall, and two years later of the collapse of the Soviet Union, provides a medium-term perspective from which to reflect on the nature of the societies of "actually existing socialism," and in particular on the economic position once held by their working classes. The need for such an examination gains added weight from the triumphalist dec...