RET-enhanced measurement of relaxation time constants of LOV2-based optogenetic actuators

Optogenetic actuators exist in either active or inactive states. Absorption of light drives transition of the chromophore to the activated state, whereas thermal processes typically cause gradual relaxation to the initial or dark state. Relaxation rates determine how often activation light needs to be applied to maintain the activated state, but this rate is strongly affected by temperature and sequences surrounding the photosensor domain. Application of existing cellular optogenetic actuators and optimization of new ones therefore requires knowledge of the relaxation rates under the experimental conditions in which they are used. When proteins targeted by the actuator do not generate immediately visible responses, alternative methods are required to determine relaxation times. We describe a simple yet sensitive procedure to measure the relaxation rate constant for an optogenetic actuator. By using resonance energy transfer with a fused fluorescent protein tag to detect the change in chromophore state, low amounts of whole cell lysate are sufficient to perform the measurement.

RET-enhanced measurement of relaxation time constants of LOV2-based optogenetic actuators

Optogenetic actuators exist in either active or inactive states. Absorption of light drives transition of the chromophore to the activated state, whereas thermal processes typically cause gradual relaxation to the initial or dark state. Relaxation rates determine how often activation light needs to be applied to maintain the activated state, but this rate is strongly affected by temperature and sequences surrounding the photosensor domain. Application of existing cellular optogenetic actuators and optimization of new ones therefore requires knowledge of the relaxation rates under the experimental conditions in which they are used. When proteins targeted by the actuator do not generate immediately visible responses, alternative methods are required to determine relaxation times. We describe a simple yet sensitive procedure to measure the relaxation rate constant for an optogenetic actuator. By using resonance energy transfer with a fused fluorescent protein tag to detect the change in chromophore state, low amounts of whole cell lysate are sufficient to perform the measurement.

Study of structural and dielectric properties of La0.9Na0.1CrO3- and Ni0.5Cu0.5Fe2O4-based composites

The preparation of [Formula: see text][Formula: see text]CrO3 (LNCO), [Formula: see text][Formula: see text]Fe2O4 (NCFO) and their composites of the type [Formula: see text] [Formula: see text][Formula: see text]CrO3 (LNCO) [Formula: see text] ([Formula: see text]) [Formula: see text][Formula: see text]Fe2O4 (NCFO) [Formula: see text], 0.50[Formula: see text] through solid state route is reported. From X-ray diffraction data analysis, the parent [Formula: see text][Formula: see text]CrO3 was found to crystallize in orthorhombic structure (Pnma) while [Formula: see text][Formula: see text]Fe2O4 has crystallized into the cubic structure (Fd3[Formula: see text]) further verified via Retvield refinement. The morphology and compositional studies were carried out using field emission scanning electron microscopy (FESEM) and energy dispersive analysis of X-rays (EDAX), respectively. Lattice structure was confirmed via Raman characterization for the prepared samples. The sample formation was further verified through Fourier transform Infra-Red (FTIR) spectroscopy. The dielectric studies reveal the [Formula: see text][Formula: see text]CrO3[Formula: see text] and [Formula: see text][Formula: see text]Fe2O4[Formula: see text] exhibit high dielectric constant. However, their composites show abrupt drop in dielectric constant. The electric modulus study confirmed that the samples exhibit non-Debye character with spread of relaxation time constants.

BEHAVIORS OF PHOTOCONDUCTIVE DETECTORS BASED ON MAPbI3 PEROVSKITE FILMS

The CH3NH3PbI3 films were synthesized by a facile low-cost solution process and were used to fabricate photoconductive detectors. The perovskite photodetector is very sensitive to light, with a high responsivity of 5.51[Formula: see text]mA/W and a sensitivity of 50 at 5[Formula: see text]V under 350[Formula: see text]nm light illumination. The device exhibits the fast rise and decay processes with similar appearance, and the relaxation time constants are 270 and 300[Formula: see text]ms, respectively. The photo-current shows an evident saturation, without further increase for prolonging the illumination period. The perovskite photodetectors display high responsive performances to short-wavelength lights. This study is expected to provide a fundamental knowledge of perovskite photodetectors with high speed and repeatability for practical applications.

The effect of solvent relaxation time constants on free energy gap law for ultrafast charge recombination following photoinduced charge separation

Ultrafast low exergonic charge recombination following photoinduced charge separation proceeds in a non-equilibrium mode and its rate constant is nearly independent of the free energy gap.