Antimicrobial photodynamic therapy (APDT) is a promising approach to overcome antimicrobial resistance. However, for widespread implementation of this approach, approved photosensitizers are needed. In this study, we used commercially available preparations (Calendulae officinalis floridis extract, Chamomillae recutitae floridis extract, Achillea millefolii herbae extract; Hypericum perforatum extract; Eucalyptus viminalis folia extract) as photosensitizers for inactivation of gram-negative (Pseudomonas aeruginosa) and gram-positive (Staphylococcus aureus) bacteria. Spectral-luminescent analysis has shown that the major chromophores are of chlorophyll (mainly chlorophyll a and b) and hypericin nature. The extracts are efficient generators of singlet oxygen with quantum yield (gamma(Delta)) from 0.40 to 0.64 (reference compound, methylene blue with gamma(Delta) = 0.52). In APDT assays, bacteria before irradiation were incubated with extracts for 30 min. After irradiation and 24 h of incubation, colony-forming units (CFU) were counted. Upon exposure of P. aeruginosa to radiation of 405 nm, 590 nm, and 660 nm at equal energy dose of 30 J/cm(2) (irradiance - 100 mW/cm(2), exposure time - 5 min), the most pronounced effect is observed with blue light (>3 log(10) reduction); in case of S. aureus, the effect is approximately equivalent for light of indicated wavelengths and dose (>4 log(10) reduction).

The effects of radiation from laser and LED sources with wavelengths λ = 405 and 445 nm on the metabolic activity of cultured somatic cells were compared. A more pronounced inhibitory effect was observed upon exposure to light with λ = 405 nm. Fundamental differences in the action of monochromatic and quasi-monochromatic light were not noted. The photobiological effect was shown to be due to photochemical processes involving various reactive oxygen species, the contribution of which to cell inactivation depended on the time after the termination of irradiation. Porphyrin components were detected for the first time in fluorescence spectra of suspensions of living cells in addition to the flavin component. It was concluded based on a comparison of the absorption characteristics of flavin and porphyrin sensitizers, chemiluminescence analysis, and the biological effects of radiation with λ = 405 and 445 nm that endogenous porphyrins with the most intense absorption in this area made the determining contribution to singlet oxygen formation in cells when exposed to radiation with λ = 405 nm. The contribution of flavins was more pronounced under the action of radiation with λ = 445 nm, which corresponded to their absorption spectrum maximum and the absorption minimum of endogenous porphyrins.

The role of nanodiamonds in the reaction of photochemical transformation of tryptophan in the presence of halogenated carbohydrates is studied. Photochemical transformation of free tryptophan in a suspension of diamond nanoparticles and in a hybrid complex with the latter under UV irradiation in the presence of chloroform is investigated. The data obtained in the course of the stationary and time-resolved studies reveal the presence of the nonradiative transfer of the electronic-excitation energy between tryptophan molecules and products of its photodecomposition in the case of covalent complex with the nanodiamond. It is demonstrated that this energy transfer enhances the integral intensity of fluorescence in the spectral interval around ~450 nm. The covalent complex of tryptophan and nanodiamond can thus be used as a fluorescent marker of the presence of chloroform in a solution.

The role of nanodiamonds in the reaction of photochemical transformation of tryptophan in the presence of halogen hydrocarbons has been studied. The photochemical transformation of free tryptophan in a suspension with diamond nanoparticles and in a hybrid complex with them when exposed to UV radiation in the presence of chloroform is investigated. Data from stationary and time-resolved spectroscopic studies show the presence of non-radiative transfer of electron excitation energy between tryptophan molecules and its photodestruction products for the case of a covalent complex with a nanodiamond. It is shown that in the presence of energy transfer, an increase in the intensity of integral fluorescence occurs in the range of ~ 450 nm. Thus, a covalent tryptophan complex with a nanodiamond can serve as a fluorescent marker for the presence of chloroform in solution.

Complex study of quadrupolar azacrown dye (E,E)-5,5 '-Bis[2-(4-(4',70,10',13',16'-pentaoxa-1 azacyclooctadecyl)phenyl)ethenyl]-2,2 '-bipyridine 1 was performed. Electronic spectra of absorption and fluorescence in different solvents exhibit strong solvatochromism. Electrooptical absorption measurements (EOAM) were performed to determine the electric dipole moments. These measurements gave large values of dipole moments in the ground mu(g) and Franck-Condon excited state leFC equal to 6.8 +/- 0.14C m and 39.3 +/- 0.3C m, respectively. Furthermore, the results of EOAM suggest the existence two conformers in the ground state with close energies of electronic transitions. Density functional theory (DFT) calculations directly show that the shape of this molecule is not planar in the ground state and also allows the existence of two stable conformers with close energies. They appeared due to different orientations of the left and right pyridine fragments of the solute. The energies, electric dipole moments and dependences of dipole moments on the strength of applied electric field were calculated for found stable conformers of 1. DFT calculations with TD / B3LYP / 3-21G and cc-pVDZ (Time Depend) approach show that external electric field increases dramatically the dipole moments of the solute under study. The higher field intensity the larger the excited electric dipole in the range intensities from zero to similar to 2.8 x 10(9) V/m. (C) 2021 Published by Elsevier B.V.

The prospects for thermal imaging and spectral technology in organizing the monitoring of laser technology processes for high-temperature modification of structural materials are analyzed. It is shown that the use of thermal imaging technology is appropriate during setup of these processes. For continuous monitoring it is more promising to use small-sized spectral technology. Solutions are proposed in which it can be used to conduct continuous monitoring based on the determination of two parameters: the effective heating temperature of the treated surface in the interaction region of the laser radiation and a parameter associated with the effective heating area. The prospects for introducing small-sized spectral devices for continuous monitoring into the feedback loop of the control system for laser systems are demonstrated.

The role of nanodiamonds in the reaction of photochemical transformation of tryptophan in the presence of halogen hydrocarbons has been studied. The photochemical transformation of free tryptophan in a suspension with diamond nanoparticles and in a hybrid complex with them when exposed to UV radiation in the presence of chloroform is investigated. Data from stationary and time-resolved spectroscopic studies show the presence of non-radiative transfer of electron excitation energy between tryptophan molecules and its photodestruction products for the case of a covalent complex with a nanodiamond. It is shown that in the presence of energy transfer, an increase in the intensity of integral fluorescence occurs in the range of ~ 450 nm. Thus, a covalent tryptophan complex with a nanodiamond can serve as a fluorescent marker for the presence of chloroform in solution. Keywords: nanoscale diamonds, hybrid complexes, tryptophan phototransformation, spectral-luminescent properties, fluorescence decay kinetics, chloroform.

We present study on spectral-luminescent characteristics medicinal plant extracts, their ability to generate singlet oxygen upon photoexcitation and photodynamic effects of extracts on mammalian cell culture and different taxonomic groups of bacteria.

For the first time, using sturgeon sperm as a model system, sensitive to optical radiation, the comparative studies of biological effect of continuous wave, quasi-continuous wave, nano- and picosecond laser radiation under conditions with equal average irradiance (3 mW/cm2) and wavelength (532 nm) have been carried out. Analyzing the parameters of spermatozoa motion it has been shown that, depending on the energy dose and mode of laser operation, the radiation may have both stimulatory and inhibitory effect on the velocity of motion and spermatozoa motility duration as well as on sustaining of functional characteristics of cold-stored sperm. The possibility of increasing the fertilization rate due to use of the sperm preliminary treated with laser radiation is demonstrated. For the first time, the possibility of enhancement of biological effect going from continuous wave to quasi-continuous wave laser radiation at equal irradiance and wavelength has experimentally been proven. It is shown that the difference in biological effect of continuous wave, quasi-continuous wave, nano- and picosecond laser radiation is due to amplitude (peak) values of intensity. Using fluorescence analysis and luminol-dependent chemiluminescence assay, evidence for the participation of endogenous flavins and metal-free porphyrins in sensitized ROS formation (singlet oxygen, hydrogen peroxide, and hydroxyl radicals) in sturgeon sperm was obtained. Mechanisms of photochemical and photothermal reactions explaining the difference in efficacy of action of laser radiation in above modes are discussed.

Electrooptical absorption measurements (EOAM), solvatochromic dependences and quantum chemical simulations testify to large dipole moments change of two quadrupolar oligophenylenevinylenes upon transition to Franck-Condon excited state mu(FC)(e). The values of the dipole moments mu(g) and mu(FC)(e) are in the range [(4.2 - 4.9)10(30)] C m and (30.8 - 47.0)10(30)C m, respectively. The relations of dipole moments in the ground and excited states determined by EOAM correlate well with results obtained via the solvatochromic method. Calculations carried out by density functional theory (DFT) show that optimized configuration of the ground state of these molecules is not planar. The results from all methods applied unequivocally show the structural symmetry breaking in the studied compounds. (C) 2021 Elsevier B.V. All rights reserved.

From electrooptical absorption measurements (EOAM) follows that the dipole moments of azacrown ketocyanine dyes 2,5-di{(E)-1-[4-(4,7,10,13-tetraoxa-1-azacyclopentadecyl)phenyl]methylidene}-1-cyclopentanone (Compound 1) and (E)-1-(2-hydroxy-4methoxyphenyl)-3-[4-(4,7,10,13-tetraoxa-1-azacyclopentadecyl)phenyl]-2-propen-1-one (Compound 2) in the equilibrium ground state μg and the change of dipole moments upon transition to the excited Franck–Condon state Δaμ are large. This alteration causes a significant long-wavelength shift of the absorption and emission spectra, as well as large fluorescence Stokes shift with increasing polarity of the solvent.

We have developed a method for online monitoring of blood levels of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, methemoglobin, and sulfhemoglobin using the diffuse reflectance spectrum of the mucosa of the lip or tongue of the patient, measured at a distance from the area to which the exciting radiation is delivered. The method is based on simple analytical expressions approximating the dependence of the diffuse light signals on the absorption coefficient, the transport scattering coefficient, the scattering anisotropy factor, and the refractive index of the mucosa. We have estimated the uncertainties in the method when there is a priori uncertainty in the optical parameters of the tissue. We have analyzed the experimental diffuse reflectance spectra of the mucosa of the lip, demonstrating that the hemoglobin composition of the studied tissue corresponds to normal physiological data.

This paper discusses the autofluorescence kinetics of healthy and tumorous tissues of the pituitary, as well as their diffuse scattering spectra in the wavelength ranges, respectively, of 380-600 and 350-1000 nm. Measurements were made by means of apparatus consisting of two units, a time-correlated photon-counting system, and a unit for exciting and recording the spectra of diffusely scattered light. It is found that a significant difference is observed in the mean autofluorescence time of tumorous and healthy tissues in the 380-600-nm spectral range. It is established that the intensity of diffusely reflected light is significantly lower in samples of healthy tissues than in samples of pituitary adenoma in the wavelength range 650-1000 nm. The sensitivity and specificity of the identification of the pituitary tissues after the data were processed by means of discriminant analysis were 100%. (C) 2014 Optical Society of America.

We have derived simple analytical expressions that enable highly accurate calculation of diffusely reflected light signals of skin in the spectral range from 450 to 800 nm at a distance from the region of delivery of exciting radiation. The expressions, taking into account the dependence of the detected signals on the refractive index, transport scattering coefficient, absorption coefficient and anisotropy factor of the medium, have been obtained in the approximation of a two-layer medium model (epidermis and dermis) for the same parameters of light scattering but different absorption coefficients of layers. Numerical experiments on the retrieval of the skin biophysical parameters from the diffuse reflectance spectra simulated by the Monte Carlo method show that commercially available fibre-optic spectrophotometers with a fixed distance between the radiation source and detector can reliably determine the concentration of bilirubin, oxy- and deoxyhaemoglobin in the dermis tissues and the tissue structure parameter characterising the size of its effective scatterers. We present the examples of quantitative analysis of the experimental data, confirming the correctness of estimates of biophysical parameters of skin using the obtained analytical expressions.

We have studied complex formation between molecules of the fluorescent probe 1-anilinonaphthalene-8-sulfonate (1,8-ANS) and the major form (A 1 ) and a minor form (A b ) of hemoglobin. The contribution of the longlived component f 3 to the kinetic curves for fluorescence decay in HbA 1b solutions is 0.021–0.036, which indicates a dramatic decrease (compared with HbA 1 ) in the accessibility of the central cavity of HbA 1b for binding 1,8-ANS. Disappearance of the long-lived component f 3 in the fluorescence decay kinetics of 1,8-ANS in HbA 1b solutions in the presence of inositol hexaphosphate (IHP) suggests that the regulatory region of HbA1b is completely inaccessible for interaction both with the negatively charged molecules of the probe and with natural regulators of the transport function for this form of the heme protein.

Dipole moments of (E,E)-2,5-bis[2-(4-N,N-dipropylaminophenyl)ethylenyl]-3,6-dimethylpyrazine (VS365) quadrupolar dye in 1,4-dioxane and cyclohexane in addition to its instantaneous fluorescence spectra and fluorescence lifetimes in dichloromethane (pure and with added trifluoroacetic acid) were measured. Quantumchemical calculations show that the π − π conjugated system is localized in the flattest part of the molecule due to disorder in the ground-state geometry of the dye molecule and that this part is the one responsible for light absorption. The effect of localized excitation of the dye causes a considerable change in its dipole moment Δaμ. Various fluorescent forms of the dye that feature considerably spaced emission spectra and different fluorescence lifetimes originate by adding trifluoroacetic acid to the solution of oligophenylenevinylene in dichloromethane.

The spectral and temporal characteristics of new 6,12-dimethoxyindolo[3,2-b]carbazole, 5,11-dimethyl-6,12-dimethoxyindolo[3,2-b]carbazole, and 5,11-dihexyl-6,12-di(hexyloxy)indolo[3,2-b]carbazole fluorescence probes in organic solvents and protein complexes are studied. The dipole moments of indolocarbazoles in 1,4-dioxane were measured by electrooptical absorption method. The measured dipole moments have values within the range of (3.1–3.6) × 10−30 C m in the equilibrium ground state and increase to (4.8–5.6) × 10−30 C m after excitation. The excited state lifetime of indolocarbazole derivatives increases with increasing polarity and viscosity of the environment. The binding of indolocarbazoles with trypsinogen and human serum albumin increases the fluorescence intensity, changes the intensity ratio of fluorescence bands, and increases the average excited state lifetime of indolocarbazoles. The analysis of the instantaneous fluorescence spectra and fluorescence decay parameters at different wavelengths revealed the existence of several types of probe binding sites in proteins. It is found that the fluorescence characteristics of indolocarbazole derivatives depend on the conformation rearrangements of trypsinogen due to its thermal denaturation.