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The photoluminescence spectra of the dominant H3 and H4 centers in a natural diamond sample, which is preliminarily characterized by optical and infrared spectrophotometry, are excited by femtosecond laser pulses with a wavelength of 470 nm and varying intensity. Saturation of the photoluminescence intensity of the H3 and H4 centers normalized by the intensity of laser radiation is observed and attributed to the saturation of the resonance transition responsible for the excitation. This makes it possible for the first time to estimate the absorption cross sections of H3 and H4 centers, which can be compared with values known from the literature and those determined from photoluminescence kinetics. The total concentration of H3 and H4 centers can then be found. Taking into account the known absorption coefficient of the sample at a wavelength of 470 nm and the previously established ratio of the contributions from H3 and H4 centers, their concentrations have been estimated separately for the first time. [ABSTRACT FROM AUTHOR]

The dependences of the fluorescence intensity and anisotropy of molecular rotors SYBR Green (SG) and double-stranded DNA with 10, 20, and 100 base pairs on their relative concentrations in solutions and on the viscosity of the medium were studied. It was shown that an increase in the fluorescence intensity with an increase in the SG concentration and a subsequent leveling off at a constant value was associated with an initial increase in the number of SG molecules intercalated in DNA and further saturation with the formation of nonfluorescent states. A generalized model that takes into account both internal rotations and rotational diffusion of the molecular complex as a whole was developed to explain the sharp drop in fluorescence anisotropy due to Forster intramolecular energy transfer between DNA-bound SG molecules. The proposed model made it possible to calculate universally the obtained experimental dependences of the fluorescence anisotropy on the viscosity of the medium at various dye/DNA ratios and to estimate the Forster energy transfer rates. [ABSTRACT FROM AUTHOR]

The article examines published evidence regarding chemo-fog/chemo-brain, the condition where there is a diminution in certain cognitive functions in some patients during and after adjuvant cancer chemotherapy. Subjective or objective measures of the cognitive defects that give rise to the terms include a clock-drawing test and the Functional Assessment of Cancer Therapy. Chemo-fog or chemo-brain effect is dose-related if the cause of the condition is chemo-therapeutic drugs.