Aleksandr Aleksandrovsky | Institute of Physics, Russian Academy of Sciences (original) (raw)

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Papers by Aleksandr Aleksandrovsky

Crystals

AgGd(MoO4)2:Ho3+/Yb3+ double molybdates with five concentrations of Ho3+ and Yb3+ were synthesize... more AgGd(MoO4)2:Ho3+/Yb3+ double molybdates with five concentrations of Ho3+ and Yb3+ were synthesized by the microwave employed sol–gel based process (MES), and the crystal structure variation, concentration effects, and spectroscopic characteristics were investigated. The crystal structures of AgGd1−x−yHoxYby(MoO4)2 (x = 0, 0.05; y = 0, 0.35, 0.4, 0.45, 0.5)at room temperature were determined in space group I41/a by Rietveld analysis. Pure AgGd(MoO4)2 has a scheelite-type structure with mixed occupations of (Ag,Gd) sites and cell parameters a = 5.24782 (11) and c = 11.5107 (3) Å, V = 317.002 (17) Å3, Z = 4. In doped samples, the sites are occupied by a mixture of (Ag,Gd,Ho,Yb) ions, which provides a linear cell volume decrease with the doping level increase. Under the excitation at 980 nm, AGM:0.05Ho,yYb phosphors exhibited a yellowish green emission composed of red and green emission bands according to the strong transitions 5F5 → 5I8 and 5S2/5F4 → 5I8 of Ho3+ ions. The evaluated pho...

Journal of Solid State Chemistry

Journal of Alloys and Compounds

Exploration of structural, vibrational and spectroscopic properties of self-activated orthorhombi... more Exploration of structural, vibrational and spectroscopic properties of self-activated orthorhombic double molybdate RbEu(MoO 4) 2 with isolated MoO 4 units,

Molecular Therapy - Nucleic Acids

Novel nanoscale bioconjugates combining unique plasmonic photothermal properties of gold nanopart... more Novel nanoscale bioconjugates combining unique plasmonic photothermal properties of gold nanoparticles (AuNPs) with targeted delivery using cell-specific DNA aptamers have a tremendous potential for medical diagnostics and therapy of many cell-based diseases. In this study, we demonstrate the high anticancer activity of aptamer-conjugated, 37-nm spherical gold nanoparticles toward Ehrlich carcinoma in tumor-bearing mice after photothermal treatment. The synthetic anti-tumor aptamers bring the nanoparticles precisely to the desired cells and selectively eliminate cancer cells after the subsequent laser treatment. To prove tumor eradication, we used positron emission tomography (PET) utilizing radioactive glucose and computer tomography, followed by histological analysis of cancer tissue. Three injections of aptamer-conjugated AuNPs and 5 min of laser irradiations are enough to make the tumor undetectable by PET. Histological analysis proves PET results and shows lower damage of healthy tissue in addition to a higher treatment efficiency and selectivity of the gold nanoparticles functionalized with aptamers in comparison to control experiments using free unconjugated nanoparticles.

The influence of weak irradiation on the aggregation stability of quantum dots is considered. It ... more The influence of weak irradiation on the aggregation stability of quantum dots is considered. It was shown that under combined UV and visible light irradiation, a gradual increase in spontaneous aggregation takes place, testifying decrease in stabilizing potential barrier height. Thereby, the laser-induced controllable self-assembly of CdTe QDs is recommended to be performed over a time period between 80 and 100 min after the beginning of low intensity irradiation under conditions equivalent to those applied in this study.

The journal of physical chemistry. B, Jan 15, 2017

The employment of colloid quantum dots in a number of applications is limited by their instabilit... more The employment of colloid quantum dots in a number of applications is limited by their instability under light irradiation. Additional methods of photostability enhancement of UV+visible-irradiated TGA-stabilized CdTe quantum dots are investigated. Photostability enhancement was observed via either addition of sodium sulphite in the role of chemical oxygen absorber or addition of 1% gelatin, or, finally, by additional stabilization by bovine serum albumine (BSA). The latter method is the most promising, since it not only enhances the quantum dots' photostability but also makes them more biocompatible and extends the possibilities of their biological applications.

Dalton Trans., 2016

Triple molybdates NaCaLa(1−x−y)(MoO4)3:xEr3+,yYb3+ were synthesized by the microwave sol–gel method.

Tunable femtosecond pulses are generated in the VUV down to 121 nm using random quasi-phase-match... more Tunable femtosecond pulses are generated in the VUV down to 121 nm using random quasi-phase-matching in strontium tetraborate, the shortest wavelength ever produced with a second-order nonlinear optical crystal.

Journal of Siberian Federal University. Mathematics & Physics, 2015

Applied Physics B, 2014

Self-organized aggregation of nanoparticles in external resonant laser field is considered using ... more Self-organized aggregation of nanoparticles in external resonant laser field is considered using Brownian dynamics model. Formation probabilities are calculated for the pair of particles in dependence on laser wavelength and mutual orientation of particles. Times required for aggregation are calculated. Possibility of efficient aggregation using pulsed laser is deduced.

2014 International Conference Laser Optics, 2014

ABSTRACT Self-organized aggregation of nanoparticles in external resonant laser field is consider... more ABSTRACT Self-organized aggregation of nanoparticles in external resonant laser field is considered using Brownian dynamics model. Formation probabilities are calculated for the pair of particles in dependence on laser wavelength and mutual orientation of particles. Times required for aggregation are calculated. Possibility of efficient aggregation using pulsed laser is deduced.

Theoretical Foundations of Chemical Engineering, 2012

ABSTRACT Luminescent Y1.74Eu0.16Bi0.1O3 films have been obtained by extraction pyrolytic method. ... more ABSTRACT Luminescent Y1.74Eu0.16Bi0.1O3 films have been obtained by extraction pyrolytic method. The for�mation of a crystalline structure in the film upon isothermal annealing in air at 600–650°C was established by X�ray diffraction. Single�phase Y1.74Eu0.16Bi0.1O3 films begin to exhibit luminescent properties after pyrol�ysis at 500°C; the intensity of luminescence increases with increasing temperature. The films annealed at 800°C consists of defect�-free homogeneous crystallites with sizes of about 0.7 μm and demonstrats high lumi�nescence intensity

Physica B: Condensed Matter, 2006

The room-temperature EXAFS measurements have been made on FeBO 3 and VBO 3 , as well as on Fe 1Àx... more The room-temperature EXAFS measurements have been made on FeBO 3 and VBO 3 , as well as on Fe 1Àx V x BO 3 series with concentration x ¼ 0:13; 0:3, and 0.95. The first-shell Me-O bond lengths deduced from EXAFS have shown a compositional independence. It has been found that Fe 1Àx V x BO 3 forms solid solutions with random distribution of Fe 3þ and V 3þ ions. r

Doklady Akademii nauk SSSR

ABSTRACT Tunable VUV radiation is obtained by of frequency doubling of the second harmonic of Nd:... more ABSTRACT Tunable VUV radiation is obtained by of frequency doubling of the second harmonic of Nd:glass laser in the naphtalene vapor. Maximum of generated power is attained at 55 C temperature of vapor cell.

Экспериментально исследованы оптические и магнитооптические спектры растворов природной нефти раз... more Экспериментально исследованы оптические и магнитооптические спектры растворов природной нефти различного происхождения и ее тяжелых фракций в видимом диапазоне оптического излучения. Обнаружен магнитный круговой дихроизм (МКД) нефти в области длин волн ~ 550 нм. Показано, что вид спектров МКД зависит от происхождения сырья, величина магнитного дихроизма пропорциональна концентрации нефти в растворе. Сопоставление данных магнитооптической спектроскопии со спектрами электронного парамагнитного резонанса (ЭПР) и химическим составом образцов позволило сделать вывод о том, что наблюдаемая магнитооптическая активность обусловлена присутствием ионов VO2+ в исследованных образцах нефти. Обнаруженная магнитооптическая активность природной нефти может стать основой уникального метода анализа состава и свойств нефтей различного происхождения и их тяжелых фракций.

AIP Advances

Visible magnetic circular dichroism (MCD) in Pr1-xSrxMnO3 with x=0.2 and 0.4 was investigated for... more Visible magnetic circular dichroism (MCD) in Pr1-xSrxMnO3 with x=0.2 and 0.4 was investigated for the first time. Samples for the investigation – polycrystalline films with thickness from 20 to 150 nm were prepared with the dc magnetron sputtering. MCD spectra obtained in the energy interval 1–4 eV at temperatures 100–300 K consist of several maxima with different intensities: very strong one near 3.25– 3.4 eV and a broad essentially weaker band near 2 eV. An additional maximum of opposite sign arises in the samples with x = 0.4MCD spectrum at 2.33 eV. Experimental spectra were decomposed to several Gaussian components, and their amplitudes temperature dependences were analyzed. In the case of x = 0.2, all four Gaussian components are characterized by the identical temperature dependence of their amplitudes. In the case of x = 0.4, maxima observed in different spectral intervals demonstrate different temperature dependences of their amplitudes. One more unexpected phenomenon is asso...