Various approaches to the characteristics of optical diffusion of the growing polymer foams as a specific version of the multiple scattering random media with a high level of disorder are considered. These approaches include the diffuse reflectance and transmittance measurements, low-coherence reference-based reflectometry, and full-field multi-speckle correlometry. The relationship between the key parameter of optical diffusion diagnostics, such as the transport mean free path of the probe light propagation in the foams and structural properties of polymer foams are discussed. A possible influence of the optical inversion effect under the wet-to-dry transition in expanding polymer foams on the diagnostic parameters is taken into account.
The comparative analysis of influence of low-intensity electromagnetic fields on the processes of self-assembly of core histones H2A and H2B was performed. To study the self-organization of histones H2A and H2B used the method of wedge dehydration. Image-facies analysis included their qualitative characteristics, as well as the calculation of quantitative indicators, followed by statistical analysis. It was established that electromagnetic radiation changes the self-organization of histones. At the same time, there is a differential sensitivity of histones to the influence of the red laser and UHF irradiation. Established fact influence of low-intensity electromagnetic fields on the process of self-assembly of core histones offers the prospect of further study of the biological effects of these types of radiation.
The analysis of influence of low-intensity electromagnetic field on the processes of self-assembly of core histones H3.2 and H4 was performed. To study the self-organization of histones H3.2 and H4 used the method of wedge dehydration. Image-facies analysis included their qualitative characteristics, as well as the calculation of quantitative indicators, followed by statistical analysis. It was established that UHF-Radiation (1GHz, 0,1 μW/cm2, 10 min) significantly modifies the process of self-assembly of core histones H3.2 and H4. Established fact influence of low-intensity electromagnetic field on the process of self-assembly of core histones offers the prospect of further study of the biological effects of this type of radiation.
The aim of the study was to assess the effectiveness of the original treatment of patients with psoriasis, including VLOK- 525 and the local impact of pulsed IR NEELIE. Under the supervision of a 264 patients with widespread forms of psoriasis in progresive stage (163 men and 101 women) between the ages of 24 to 63 years old (average age - 41 years), being diagnosted with the disease from 1 to 30 years ago. In the main group the complex treatment included the original laser methods apparatus " LAZMIK VLOK," with the laser head emit KL-VLOK-525-20 for intravenous laser blood irradiation and ML-635-40 for external impact. It was shown that combined laser therapy of patients with a moderate form of psoriasis (10 <PASI<50), including a local effect on psoriatic elements by pulsed red light LIL (635 nm) with a power of 40 W with a pulse repetition rate of up to 10 Hz OOO-VLOK-667 allows effectively the cease of inflammatory changes and lead to a reduction in erythema, infiltration and exfoliation.
A new approach to the interpretation of OCT probes of coarse-grained random media is considered. In the framework of the approach, the integrated scan-depth-dependent diffuse reflectivity of a probed sample is estimated using a set of OCT A-scans. A relationship between the integrated reflectivity and a transport mean free path of light propagation in the probed sample is established using Monte-Carlo simulations. The considered technique was applied for characterization of the structure of highly porous polymer (polylactide) matrices synthesized using a supercritical fluidic (SCF) foaming of a pre-plasticized raw polymer. The results of experimental verification of the considered technique are compared with similar data obtained in the framework of other approaches to OCT data interpretation.
The aim of the present work was to investigate the ability of inhibiting the growth of various strains of Staphylococcus aureus by low-intensity laser light. As object of research used methicillin-sensitive and methicillinresistant strains of Staphylococcus aureus. For irradiation was used a semiconductor laser, which generates linearly polarized radiation of the red spectral region (λ - 660 nm). Power density was 100 mW/cm2, irradiation time – 5, 10, 15 and 30 min, heat density respectively 30, 60, 90, and 180 J/cm2. It was established that low-intensity laser radiation has an inhibitory effect on growth of colonies of both methicillin-sensitive and methicillin-resistant strains of Staphylococcus aureus. But resistant strain is more sensitive to the action of red light, as the bacteriostatic effect is detected at the lower doses.
The study of antimicrobial photodynamic activity of subingibing concentrations of aqueous solutions of silver nanoparticles under the photodynamic action of blue led radiation in relation to the standard and clinical strain of Staphylococcus aureus. The greatest sensitivity to the combined effects of radiation and metal nanoparticles showed methicillin-resistant clinical strain of Staphylococcus aureus. The samples containing silver nanoparticles presented in the experiment were characterized by a pronounced antimicrobial activity and can be considered as promising photosensitizers for photodynamic therapy of pyoinflammatory diseases.
Analysis of the influence of low-intensity electromagnetic field on the processes of self-assembly of the lincer histone H1 was performed. To study used a wedge dehydration method. Image-analysis of facies included their qualitative characteristics and calculation of quantitative parameters with subsequent statistical processing. It was established that UHF-Radiation (1GHz, 0,1 μW/cm2 , 10 min) significantly modifies the process of self-organization of lincer histone, which determines the possibility of the involvement of the genetic apparatus of the cell in the effects of this type of radiation on biological objects.
The influence of low-intensity electromagnetic radiation on the process of self-assembly, spectral-fluorescent characteristics and lethal effect of bacterial lipopolysaccharide (endotoxin) was performed. A solution of bacterial lipopolysaccharide exposed to electromagnetic waves with a frequency of 1 GHz, the power density of 0.1 μW/cm2 for 10 min. In experiments on a large group of control and irradiated mice, a comparative analysis of the estimated lethal dose of endotoxin was performed. It was proved that UHF radiation of certain parameters reduces the lethal effects of bacterial lipopolysaccharide on 26%.
The temporal evolution of the metastable and unstable foams had been studied. Diffusion wave spectroscopy was chosen as the diagnostic method, with calculation of the correlation time of the fluctuations in the intensity of the probing radiation. It was established that the correlation time increases with the time according to the power law with different parameters, depending on the type of the evolution and was found to be equal to 0.5 for the case of the metastable and to 2,52 for the unstable foam. It was also determined that the behaviour of the correlation time agrees well with the evolution of the characteristic dimensions of the scatterers in the form of bubbles in the medium, which can be used for contactless monitoring of the foaming processes in the production of the foam-like materials for various applications, for example, in the synthesis of the biocompatible polymer matrices - scaffolds.
The influence of red laser irradiation on the growth of colonies of Staphylococcus aureus and photodynamic effect of the photosensitizer Photoditazine were performed. It was established that the emission of red laser light caused an inhibition of bacterial growth. This effect on standard strain of Staphylococcus aureus was evident only when relatively high doses of radiation (180 j/cm2). Photosensitivity of the methicillin-resistant strains was much higher: bacteriostatic effect of red light was observed already at the dose of 60 j/cm2 . Pre-treatment of bacterial cells by Photoditazine significantly enhances the inhibitory effect of the laser light.
The influence of red laser irradiation on the growth of colonies of methicillin-resistant strain of Staphylococcus aureus and photodynamic effects of the photosensitizers Photoditazine and Dimegin were performed. It was established that the red semiconductor laser (λ - 660 nm, 100 mW/cm2) at 10-, 15- and 30-mins exposure, has a direct bacteriostatic action on the growth of S. aureus. Pre-treatment of bacterial cells by Photoditazine significantly enhances the inhibitory effect. The photosensitizing action of Dimegin does not appear at influence on methicillin-resistant S. aureus.
Analysis of the influence of red laser irradiation on the processes of self-assembly of the core histones H2A and H2B was performed using a wedge dehydration method. Image-analysis of facies included their qualitative characteristics and calculation of quantitative parameters with subsequent statistical processing. It was established that linearly polarized red laser light (λ - 660 nm, 1 J/cm2) significantly modified the process of self-assembly of core histone H2B, whereas the structure of the facies of H2A histone changed to a lesser extent. Histones were used in the form of aqueous salt solutions. The effect of red light seems to result from the formation of singlet oxygen by direct laser excitation of molecular oxygen.
Random changes in the polarization states of partial contributions to the multiple scattered light fields in a random medium are analyzed using the statistical modeling of polarized light transport in the medium. The mapping of local polarization states on the Poincaré sphere surface clearly indicates the different scenarios of the "order – disorder" transition in the case of Rayleigh and Mie scatterers. If the random medium consisting of small particles is probed by a linearly polarized laser beam, then propagating partial waves keep their linear polarization state but the dispersion of azimuth angles rapidly increases with the increasing average propagation path for these waves. On the contrary, the multiple scattering by random ensembles of the large particles is accompanied by random transformations of the linear polarization of propagating waves to the elliptical polarization. The obtained results are considered in the relation to the known features of polarization decay in the random media.
The effect of excitation of local surface modes in semiconductor nanoparticles is studied experimentally and theoretically for various compounds: titanium dioxide, titanium nitride, tungsten disilicide, molybdenum disilicide. Enhancement of depolarizing properties for non-spherical titania nanoparticles (nanoplatelets and nanoribbons) associated with the excitation of local surface modes is considered. The possibility to retrieve the dielectric function spectrum from the depolarization factor measurements for low-dimensional nanoparticles is discussed.
This study focuses on the analysis of the temperature-dependent dynamics of scatterers in aqueous solutions of gelatin with added scattering centers (submicron particles of titanium dioxide), whose characterized by high scattering efficiency, during the process of gelation. The technique of full field speckle-correlometry with a localized source of probing radiation and the spatial filtering of the speckle-modulated images of the medium surface was applied to investigate systems with different values of the volume fraction of scatterers. It was shown that the Arrhenius equations with significantly different values of the activation energy can describe the temperature dependencies of the correlation time of speckle intensity fluctuations for temperature ranges above and below the gelation characteristic temperature. Note that the correlation time of speckle intensity fluctuations is determined by the mobility of the scattering centers in the medium. This suggests the existence of transition between two different regimes of spatially limited diffusion of scattering centers in the probed medium under the condition of "sol-gel" transition. The estimated values of activation energy of spatially limited scatter diffusion in the studied systems at low temperatures correlate with the published values of the gelation activation energy for gelatin aqueous solutions.
The effect of increase in the uncertainty of local polarization states of laser light forward scattered by random media was studied in the experiments with phantom scatterers. At macroscopic level this effect is related to decay in the degree of polarization of scattered light in the course of transition from single to multiple scattering. Gelatin layers with embedded titania particles were used as the phantom scatterers. Features of distributions of local polarization states in various polarization coordinates were considered.
The aim was to study the possibility of using polarimetry methods of performance evaluation of blood plasma of patients with breast cancer and spectroscopy method in the diagnosis of breast cancer and determine the criteria for their use of non-invasive screening for problems.
The aim was to study the possibility of using polarimetry methods of performance evaluation of blood plasma of patients
with breast cancer and spectroscopy method in the diagnosis of breast cancer and determine the criteria for their use of
non-invasive screening for problems.
The morphological peculiarities of TS mitral valve of the heart of man in normal and abnormal spaced strings of the left ventricle and the study of their structural features depending on the location was studied. There are given the results of comparative statistics, correlation and fractal study population Mueller-matrix images (MMI) of healthy and abnormal (early forms that are not diagnosed by histological methods) BT normal and abnormally located tendon strings left ventricle of the human heart. Abnormalities in the structure of the wings, tendon strings (TS), mastoid muscle (MM) in inconsistencies elements and harmonized operation of all valve complex shown in the features of the polarization manifestations of it laser images.
We studied a methods of assessment of a connective tissue of cervix in terms of specific volume of fibrous component and an optical density of staining of connective tissue fibers in the stroma of squamous cancer and cervix adenocarcinoma. An absorption spectra of blood plasma of the patients suffering from squamous cancer and cervix adenocarcinoma both before the surgery and in postsurgical periods were obtained. Linear dichroism measurements transmittance in polarized light at different orientations of the polarization plane relative to the direction of the dominant orientation in the structure of the sample of biotissues of stroma of squamous cancer and cervix adenocarcinoma were carried. Results of the investigation of the tumor tissues showed that the magnitude of the linear dichroism Δ is insignificant in the researched spectral range λ=280-840 nm and specific regularities in its change observed short-wave ranges.
The features of formation of interferometer output in the case of a broadband light source and random medium as a retro-reflector in the interferometer object arm are considered. It is shown for the large values of the pathlength difference the interferometer output decays exponentially with the decay rate dependent on the transport parameters of a probed random medium. This allows us to determine the transport mean free path of light propagation in the medium. This approach can e applied not only for the strongly scattering media, but also for scattering samples characterized by non-diffusive regime of light propagation.
The possibility to increase the sensitivity of the full field speckle-correlometry to the scatter mobility variations is
discussed. The considered technique is based on application of diagnostic parameters such as the skewness and the
kurtosis of probability distributions of intensity fluctuations for time-integrated dynamic speckles.
Diffuse reflectance of polarized light is studied in application to characterization of multiple scattering anisotropic
media (such as, e.g., the fibrous tissues) with the use of focused probe laser beam. The theoretical model for description
of the transport properties (the values of transport scattering coefficients and effective refractive index for different
polarization states of probe light) of closely packed systems of partially disordered dielectric cylinders is considered on
the base of coherent potential approximation. The influence of structural and optical characteristics of fibrous systems
(such as the volume fraction of cylindrical scatters, their average diameter, the degree of disorder, refractive indices of
scatters and surrounding medium) on diagnostical parameters determined with the polarization videoreflectometry can
be analyzed in the framework of the considered theoretical model. The obtained theoretical results satisfactorily agree
with the experimental data on polarization videoreflectometry and spectral-polarization measurements in the
transmittance mode of in-vitro samples of demineralized bone, muscular tissue and phantom samples (partially oriented
polymer films).
Application of polarized probe light and polarization discrimination of backscattered light give the additional possibilities for characterization and imaging of various diseases localized in superficial layers of tissues because of the high sensitivity of polarization state of multiply scattered light, which is detected in the backscattering mode, to alterations in optical parameters of the probed tissue. In this work we compare two methods of analysis of multiple scattering anisotropic media (demineralized bone), such as laser videoreflectometry and method of coherent backscattering. The agreement between results obtained with these two techniques is satisfactory.
Monte-Carlo simulations are applied to study the polarized light transport from a localized light source in layered multiple scattering media with the expressed macroscopic anisotropy of optical properties. The shape and orientation of the equal intensity profiles for various polarization states of backscattered light are analyzed in the dependence on the distance between the source and detection point. Obtained results are compared with the experimental results obtained by other authors in the experiments with tissue phantoms and in-vivo tissues. Various numerical techniques for reconstruction of the optical parameters of multiple scattering anisotropic media on the basis of polarization analysis of backscattered light are considered. The developed technique can be used as the theoretical basis for morphological diagnostics of anisotropic tissue layers consisting of collagen fibrils (such as, e.g., derma) by means of polarization videoreflectometry.
Monte-Carlo technique is applied to study the light transport from a localized light source in layered multiple scattering media with the expressed macroscopic anisotropy of underlying layers. The shape and orientation of the equal intensity profiles and the pathlength distributions of backscattered light are analyzed in the dependence on the distance between the source and detection point. Obtained results are compared with the experimental results obtained by other authors in the experiments with tissue phantoms and in-vivo human and mouse skin.
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