V.N. Nikiforov

Radio frequency radiation-induced hyperthermia using Si nanoparticle-based sensitizers for mild cancer therapy.

Offering mild, non-invasive and deep cancer therapy modality, radio frequency (RF) radiation-induced hyperthermia lacks for efficient biodegradable RF sensitizers to selectively target cancer cells and thus avoid side effects. Here, we assess crystalline silicon (Si) based nanomaterials as sensitizers for the RF-induced therapy. Using nanoparticles produced by mechanical grinding of porous silicon and ultraclean laser-ablative synthesis, we report efficient RF-induced heating of aqueous suspensions of the nanoparticles to temperatures above 45-50°C under relatively low nanoparticle concentrations (<1 mg/mL) and RF radiation intensities (1–5 W/cm2). For both types of nanoparticles the heating rate was linearly dependent on nanoparticle concentration, while laser-ablated nanoparticles demonstrated a remarkably higher heating rate than porous silicon-based ones for the whole range of the used concentrations from 0.01 to 0.4 mg/mL. The observed effect is explained by the Joule heating due to the generation of electrical currents at the nanoparticle/water interface. Profiting from the nanoparticle-based hyperthermia, we demonstrate an efficient treatment of Lewis lung carcinoma in vivo. Combined with the possibility of involvement of parallel imaging and treatment channels based on unique optical properties of Si-based nanomaterials, the proposed method promises a new landmark in the development of new modalities for mild cancer therapy.

Investigation of phase relationships and physical properties of YbPdGe compounds

Abstract A variety of physicochemical analysis techniques were employed in constructing the isothermal cross-section of the phase diagram of the YbPdGe system 870 K. Several new ternary compounds Yb 10 Pd 75 Ge 15 , Yb 20 Pd 20 Ge 60 , Yb 2 PdGe 6 , YbPdGe 2 , YbPd 2 Ge, YbPdGe, YbPd 0.5 Ge 1.5 , Yb 33.3 Pd 28 Ge 38.7 and Yb 42 Pd 13 Ge 45 were detected. The temperature dependences of the specific electric resistance were investigated for the alloys on the basis of YbPdGe, YbPd 2 Ge and YbPd 2 Ge 2 compounds as well as for Yb(PdGe) 3 (alloy from the range of solid solutions based on YbPd 3 ).

Crystal structure of the new compound Ce3Pt23Ge11

Abstract The crystal structure of the compound Ce3Pt23Ge11 has been determined by X-ray analysis of a single crystal (Enraf-Nonius CAD-4 autodiffractometer, Mo Kα radiation, 276 independent reflections, R-factor 0.0735 in isotropic approximation). This structure has been found to belong to a new structural type: space group F 4 3m, a = 17.1833(9) A , Z = 8 . The coordination polyhedra of the cerium atoms are compressed cubes, those of platinum have eight or 10 apexes and those of germanium are either trigonal prisms with an additional atom or cubes. The magnetic properties of Ce3Pt23Ge11 at low temperatures (4–100 K) were investigated. A diffuse magnetic phase transition at around 10 K was detected.

SWITCHING EFFECTS IN THE DIELECTRIC PHASE OF THE PB1-XSNXTE(IN) COMPOUNDS

Abstract The current-voltage characteristics (CVC) and switching effects have been investigated in the monocrystalline Pb 1−x Sn x Te alloys doped with In at liquid helium temperatures. Experimental results are interpreted in terms of joule heat model.

Magnetic Properties of Copper as a Constituent of Nanobridges Formed between Spatially Fixed Deoxyribonucleic Acid Molecules

The number of copper ions as constituents of a nanobridge that links two deoxyribonucleic acid (DNA) molecules that are fixed in a particle of a liquid-crystalline dispersion has been evaluated from the measurements of the magnetic susceptibility of particles in the liquid-crystalline dispersion of DNA. It has been shown that the experimental data are consistent with both theoretical assumptions on the possible structure of a nanobridge and a thermodynamic model that describes the formation of these bridges.

Optical properties of PbTe:Mn

Abstract In this paper, we investigate Mn concentration and crystal growth rate influence on optical properties of PbTe:Mn single crystals. We measured far-infrared reflectivity spectra at room temperature in the 10–250 cm −1 spectral range. The analysis of the far-infrared spectra was made by a fitting procedure based on the model of coupled oscillators. In spite of the strong plasmon-LO phonon interaction, we found that the plasma frequency decreases as Mn concentration increases, while the crystal growth rate has the opposite effect. Also, we obtained the Mn impurity in-band mode at about 50 cm −1 .

Transport and magnetic properties of the new ternary compound CeRuSi2 at low temperatures

Abstract The new cerium ternary compound CeRuSi 2 has been prepared and characterized. At a temperature T ∼ 10K this compound reveals a magnetic transition, magnetisation measurements give clear evidence for a ferromagnetic state. Above 10 K we observed paramagnetic heavy-fermion-like behaviour with an electronic specific heat coefficient γ ≃ 100 mJ/mole K 2 .

Anomalous ferromagnetism and non-Fermi-liquid behavior in the Kondo lattice CeRuSi2

The structural, electronic and magnetic properties of the Kondo-lattice system CeRuSi2 are experimentally investigated and analyzed in the series of other ternary cerium compounds. This system is shown to be an excellent model system demonstrating coexistence of the Kondo effect and anomalous ferromagnetism with a small magnetic moment which is confirmed by magnetic and μSR measurements. Data on specific heat, resistivity, heat conductivity and Seebeck coefficient are presented. Being deduced from the resistivity and specific heat data, a non-Fermi-liquid behavior is observed at low temperatures, which is unusual for a ferromagnetic Kondo system. A comparison with other magnetic Kondo lattices is performed.

Effect of hydrogen on the magnetic anisotropy and spin–reorientation transition in ErFe11Ti single crystal

Abstract The effect of hydrogenation on the magnetic properties of the intermetallic compound ErFe 11 Ti are studied. Single crystals of the hydrogen-containing compound were obtained. Magnetic characteristics of the ErFe 11 Ti and ErFe 11 TiH single crystals have been investigated in the temperature range 4.2–750 K and in magnetic fields up to 13 kOe. Upon hydrogenation, the uniaxial magnetic anisotropy is observed to increase, while the spin–reorientation temperatures T SR shifted towards lower temperatures.

Size and surface effects on the magnetism of magnetite and maghemite nanoparticles

The size effects of magnetite and maghemite nanoparticles on their magnetic properties (magnetic moment, Curie temperature, blocking temperature, etc.) have been investigated. Magnetic separation and centrifugation of an aqueous solution of nanoparticles were used for their separation into fractions; their sizes were measured by atomic force microscopy, dynamic light scattering, and electron microscopy. A change in the size leads to a change in the Curie temperature and magnetic moment per formula unit. Both native nanoparticles and those covered with a bioresorbable layer have been considered. The magnetic properties have been calculated by the Monte Carlo method for the classical Heisenberg model with various bulk and surface magnetic moments.