Using the Method of “Optical Biopsy” of Prostatic Tissue to Diagnose Prostate Cancer

The possibilities of using optical spectroscopy methods in the differential diagnosis of prostate cancer were investigated. Analytical discrimination models of Raman spectra of prostate tissue were constructed by using the projections onto latent structures data analysis(PLS-DA) method for different wavelengths of exciting radiation—532 and 785 nm. These models allowed us to divide the Raman spectra of prostate cancer and the spectra of hyperplasia sites for validation datasets with the accuracy of 70–80%, depending on the specificity value. Meanwhile, for the calibration datasets, the accuracy values reached 100% for the excitation of a laser with a wavelength of 785 nm. Due to the registration of Raman “fingerprints”, the main features of cellular metabolism occurring in the tissue of a malignant prostate tumor were confirmed, namely the absence of aerobic glycolysis, over-expression of markers (FASN, SREBP1, stearoyl-CoA desaturase, etc.), and a strong increase in the concentration of cholesterol and its esters, as well as fatty acids and glutamic acid. The presence of an ensemble of Raman peaks with increased intensity, inherent in fatty acid, beta-glucose, glutamic acid, and cholesterol, is a fundamental factor for the identification of prostate cancer.

Synthesis, microstructure, mechanical properties and luminescence of a ceramics Gd(NbxTa1−x)O4

Ceramic solid solutions GdNbx[Formula: see text]O4 ([Formula: see text]–1) were synthesized by sol–gel. Morphological particularities of microstructure were studied, strength characteristics (Young’s modulus) and stress intensity factor for mode I [Formula: see text] were evaluated. The latter is a criterion of crack resistance of the material. Luminescent properties of solid solutions GdNbx[Formula: see text]O4 were researched under UV exciting radiation. A comparatively small addition of Ta ([Formula: see text]) was shown to increase luminescence intensities of centers [Formula: see text]–O−. An addition of Ta to GdNbO4 leads to creation of solid solution [Formula: see text][Formula: see text]O4. Intensity of these centers is 3–6.5 times larger than that of GdNbO4 and GdTaO4.

Фотолюминесценция квантовых точек Zn-=SUB=-1-x-y-=/SUB=-Cu-=SUB=-x-=/SUB=-Eu-=SUB=-y-=/SUB=-S/EuL-=SUB=-3-=/SUB=- в полиакрилатной матрице

Zinc sulfide is one of the most popular luminescent semiconductors of group A(II)B(VI). Doping ZnS quantum dots with Ln3+ ions makes it possible to form nanoscale structures in a semiconductor matrix containing isolated centers of narrow-band luminescence. The introduction of quantum dots into the acrylate matrix further stabilizes the particles and allows them to form their morphology. Nanoscale structures of Zn1-x-yCuxEuyS/EuL3, where L − trifluoroacetate are anions, were synthesized by the method of emerging reagents in situ in the medium of methyl methacrylate (MMA). ZnS doping was performed by simultaneous introduction of soluble precursors of zinc sulfide, as well as copper and europium trifluoroacetates into the acrylate reaction mixture. Polymer optically transparent compositions of PMMA/Zn1-x-yCuxEuyS/EuL3 were obtained by radical polymerization of MMA in the block. The excitation of luminescence of compositions is associated with Interzone electron transitions in ZnS, with a system of levels that form alloying ions in the forbidden zone of ZnS, as well as with their own energy absorption by Eu3+ ions. Broadband luminescence of compositions is caused by intracrystalline defects formed in ZnS during doping. Narrow-band luminescence occurs as a result OF 5D0→7Fj electronic transitions in Eu3+ ions associated with quantum dots, as well as being in the polymer matrix independently of them. The transfer of energy from the donor levels of the semiconductor matrix to the levels of Eu3+ ions, followed by its release in the form of luminescence, was confirmed by the imposition of absorption bands doped with ZnS and excitation bands of luminescence compositions, as well as an increase in the intensity of narrow-band luminescence of Eu3+ ions while reducing the intensity of a wide band of recombination luminescence of doped ZnS. A decrease in the intensity of the ZnS recombination luminescence band with an increase in the concentration of Eu3+ >1.0∙10-3 mol/L ions is also associated with the formation of a layer of complex europium compounds on the particle surface that prevent the passage of exciting radiation to the particle core.

Люминесценция ионов Eu-=SUP=-3+-=/SUP=- в матрице фторированной алюмоиттриевой композиции

The optical spectra of fluorinated yttrium aluminum compositions activated by Eu3+ ions were studied. The compositions were synthesized by thermal decomposition at 800 °C of fluorine-containing complexes of yttrium, europium, and aluminum nitrate, isolated as sols from ethyl acetate (EA). The main phases of the compositions are (Y1-xEux)OF and (Y1-xEux)AlO3. Photoluminescence is associated with 5D1,2 → 7F0,1,2 and 5D0 → 7F0,1,2,3,4 electronic transitions of 4f - electrons of Eu3+ ions, replacing yttrium ions in its oxide and oxyfluoride. The dependences of luminescence on the composition and synthesis conditions of the compositions, the wavelength of the exciting radiation, and other factors are established.

Фотолюминесценция квантовых точек (Zn, Pb, Mn)S в полиакрилатной матрице

Solutions of quantum dots (Zn,Pb,Mn)S with different mole ratio of cations were obtained by colloidal synthesis in methyl methacrylate (MMA) medium. By thermal polymerization of MMA in the block, colloidal solutions are transferred to the glassy state. The optical transparency of PMMA/(Zn,Pb,Mn)S compositions at wavelengths >500 nm reaches 90% with the thickness of the absorbing layer up to 5 mm. Photoluminescence of compositions in the spectral region of 400–480 nm is associated with electron recombination at the levels of defects in the crystal structure of ZnS, in the range of 520–620 nm with 4T1 → 6A1 electron transition in Mn2+ ions. Excitation of photoluminescence occurs as a result of interband transitions in ZnS and energy transfer from the conduction band of ZnS to Mn2+ ion levels. The luminescence spectrum depends on the molar ratio of Mn2+ and Pb2+ ions, the sequence of introduction of the components into the reaction mixture, the wavelength of the exciting radiation.

Features of transmission of electromagnetic waves through composite nanoresonators including epsilon-near-zero metamaterials

Transmission of electromagnetic waves through nanometric multilayers (nanoresonators) including a main composite layer made of two alternating strips of low-absorbing dielectrics that is sandwiched between epsilon-near-zero (ENZ) or metallic spacer layers has been modeled. Analytical models are based on exact solutions of electromagnetic boundary problems. The spacers with the definite properties lead to extreme dependences of amplitude transmission coefficients on the system parameters and drastic increase in phase difference of the transmitted waves. These effects are most pronounced for subwavelength multilayer thicknesses due to multibeam interference features in the nanoresonator, and they can be amplified when the main layer and (or) the whole system thicknesses decrease. The investigated transmission features take place under variations of the system parameters such as anisotropy of the main layer materials, non-ideal realization of ENZ materials, oblique incidence of the exciting radiation (for small incidence angles). The obtained results can have applications in development of ultra-thin nanophotonics devices using phase transformation of transmitted waves.

Features of reflection of electromagnetic waves from nanometric perforated multilayers including epsilon-near-zero metamaterials

Using the exact solutions of electromagnetic boundary problems, analytical modeling of reflection of electromagnetic waves from nanometric perforated multilayers has been carried out. New features of operation of the multilayers including the substrate or layers of epsilon-near-zero (ENZ) materials are established. Presence of the ENZ main layer or substrate leads to the quickly changing and extreme values of phase and module of amplitude reflection coefficients depending on the system parameters. The ENZ (or metallic for the thicker systems) substrate has a significant impact on the transformation of phase difference of the reflected waves. The detailed numerical analysis of the obtained results for the multilayers including silver or phase change materials (germanium antimony tellurium alloy, vanadium dioxide) components is performed. The considered reflection characteristics are reasonably “stable” to variation of the system parameters such as oblique incidence of the exciting radiation (for TE or TM polarization), possible presence of magnetic properties of the layers and effective electromagnetic anisotropy of the substrate material. The obtained results can be used to develop ultra-thin (with significantly subwavelength thicknesses) transformers of phase and amplitude of reflected radiation, holograms, metasurfaces and other nanophotonics applications.

Оптический метод измерения температуры фторидных кристаллов, активированных ионами Yb-=SUP=-3+-=/SUP=- и Tm-=SUP=-3+-=/SUP=-

The fluorescence intensities ratio (FIR) method is applied for measuring the temperature inside the luminescent LiY_0.8Yb_0.2F_4:Tm^3+ crystal. The obtained results are used for monitoring of the sample temperature in the experiment when the exciting radiation waist is shifted by the focusing lens inside the sample. It is shown that a considerable change in the luminescence intensity of the LiY_0.8Yb_0.2F_4:Tm^3+ crystal (0.2%) is not accompanied by a significant change in the temperature. This verifies the hypothesis about the appearance of amplified spontaneous luminescence (ASL) of Yb^3+ ions during intense laser pumping in these crystals.

Микрокристаллические алмазные порошки как перспективные объекты для генерации многочастотного вынужденного комбинационного рассеяния-=SUP=-*-=/SUP=-

The laws of Raman scattering in microcrystalline diamond powders are investigated depending on the size of diamond microresonators in the range of 1–600 mkm. The observed effect of the anomalously high intensity of spontaneous Raman scattering in diamond microresonators is explained by the “trapping” of electromagnetic radiation in them, the wavelength of which is smaller than the size of diamond microcrystals. Due to the "trapping" of photons in diamond microresonators, the density of electromagnetic energy for excitation and secondary radiation increases. The high quality factor of the fundamental optical mode in the vibrational spectrum of diamond and the anomalous increase in the intensity of Raman scattering in diamond microresonators open up possibilities for observing low-threshold stimulated multifrequency Raman scattering in microcrystalline diamond powders. The use of the generation lines of a pulsed solid-state YAG: Nd3+ laser (λ = 1064 nm) and its optical harmonics (λ = 1064, 532, 354, 266 nm) as exciting radiation makes it possible to create a line of laser-frequency oscillators from the ultraviolet region that are equidistant in frequency shift to the terahertz range, promising for the study of biological and medical objects.

Synthesis of Core/Shell CuO-Zno Nanoparticles and Their Second-Harmonic Generation Performance / Kodols/Čaula Cuo-Zno Nanodaļiņu Sintēze Un To Spēja Ģenerēt Otrās Harmonikas Signālu

The present paper presents the method for obtaining core/shell CuO-ZnO nanoparticles and nanocoatings by using a commercially available vacuum coating system. Initially generated Cu-Zn core/shell nanoparticles have been oxidised with a highly reactive atomic oxygen beam. Second-harmonic generation has been observed in the obtained samples. The dependence of second- harmonic intensity on the wavelength of the exciting radiation is shown in the paper.