One-step synthesis of vanadium-doped anatase mesocrystals for Li-ion battery anodes.

Here we report a successful one-step synthesis of vanadium-doped anatase mesocrystals by reactive annealing of NH4TiOF3/PEG2000 mesocrystal precursors with NH4VO3. The formation solid solution Ti1-xVxO2with vanadium content up tox = 25 at% inheriting the structure of mesocrystals is observed for the first time. The doping mechanism via vapor phase transport of vanadium is proposed. The Ti1-xVxO2mesocrystals exhibit improved specific capacity of 175 mAh g-1(compared to 150 mAh g-1for pure anatase phase) and decreased potential gap between charge and discharge processes.

Gas permeation through nanoporous membranes in the transitional flow region.

An experimental study on the permeability of anodic alumina (20-120 nm) and track-etched (30 nm) nanoporous membranes for different gases in the transitional flow regime is reported in the range of Knudsen numbers from 0.1 to 10. A significant variation (up to 30%) of the membrane permeance for different gases at the same Knudsen numbers is reported with certainty. It is established that this discrepancy relates to a molecule's effective collision area, which is poorly described in the frameworks of conventional gas permeation models. Two models are proposed for the description of the effect: self-diffusion of penetrate gases due to intermolecular collisions and enhancement of the slip flow contribution due to tangential momentum accommodation growth with the decrease of a molecule's effective collision area. The best fit parameters for the simultaneous fit of the experimental data with different models for 30 membrane-gas pairs are given.

The structure and continuous stoichiometry change of 1DTbBrx@SWCNTs.

HRTEM and HAADF STEM of 1DTbBrx@SWCNT meta-nanotubes reveal three structural modifications of 1D nanocrystals within single wall carbon nanotube channels attributed to a different stoichiometry of the guest crystal. For SWCNTs with diameters Dm > 1.4 nm a most complete tetragonal unit cell is observed. When crystallization occurs inside SWCNT with Dm < 1.4 nm 1D TbBrx crystal deforms a nanotube to elliptical shape in cross section. In this case the 1D crystal unit cell becomes monoclinic, with possible loss of a part of bromine atoms. Two modifications of a monoclinic unit cell appear. One of them is characterized by single or pair vacancies in the structure of the 1D crystal. Another structure is explained by peripheral and central bromine atoms loss. An appearance of such modifications can be stimulated by electron irradiation. The loss of bromine atoms is in agreement with chemical analysis data. Electronic properties of obtained meta-nanotubes are investigated using optical absorption and Raman spectroscopy. It is shown that intercalation of terbium bromide into SWCNTs leads to acceptor doping of SWCNTs. According to local EDX analysis and elemental mapping this doping can arise from significant stoichiometry change in 1D nanocrystal indicating an average Tb:Br atomic ratio of 1:2.8 ± 0.1.

Atomically precise semiconductor--graphene and hBN interfaces by Ge intercalation.

The full exploration of the potential, which graphene offers to nanoelectronics requires its integration into semiconductor technology. So far the real-world applications are limited by the ability to concomitantly achieve large single-crystalline domains on dielectrics and semiconductors and to tailor the interfaces between them. Here we show a new direct bottom-up method for the fabrication of high-quality atomically precise interfaces between 2D materials, like graphene and hexagonal boron nitride (hBN), and classical semiconductor via Ge intercalation. Using angle-resolved photoemission spectroscopy and complementary DFT modelling we observed for the first time that epitaxially grown graphene with the Ge monolayer underneath demonstrates Dirac Fermions unaffected by the substrate as well as an unperturbed electronic band structure of hBN. This approach provides the intrinsic relativistic 2D electron gas towards integration in semiconductor technology. Hence, these new interfaces are a promising path for the integration of graphene and hBN into state-of-the-art semiconductor technology.

HRTEM of 1DSnTe@SWNT nanocomposite located on thin layers of graphite.

The method for imaging of highly sensitive nanostructures unstable under electron beam irradiation is introduced. To reduce charge and thermally generated beam damage, highly conductive multilayered graphene or thin graphite layers were used as supports for nanostructures. Well-defined crystalline structure of graphite layers enables image reconstruction by Fourier filtering and allows maintaining high quality of images. The approach was tested for imaging of highly sensitive quasi one-dimensional SnTe nanocrystals hosted inside single-walled carbon nanotubes. Relying on the filtered images and the image simulation, the structure of one-dimensional SnTe was established as a chain of fcc NaCl type unit cells, connected by the [001] edges with <110> direction coinciding with nanotube axis.

Permeability of anodic alumina membranes with branched channels.

Mass-transport properties of anodic alumina membranes exploited in a number of technological areas are strongly affected by the real pore structure and arrangement of channels that can split or terminate during the anodization process. This paper focuses on the investigation of pore branching and rearrangement caused by voltage variation in the course of the anodic oxidation of aluminum. Gas-transport measurements were utilized for the quantitative determination of an effective through porosity of multilayer anodic alumina membranes with branched channels obtained by variation of anodization voltage. It was shown that on decrease of anodization voltage a branching of pores occurs, while an increase of anodization voltage leads to the termination of some of the pores with an increase in the diameter of others. Gas permeance measurements combined with electron microscopy unambiguously prove dead-end pore formation on voltage increase, while no pore merging appears. This generally affects any mass-transport properties and applications of anodic alumina membranes as the delivery of any species (e.g. ions, gas molecules, etc) through the blocked channels is impossible.

The structure of nanocomposite 1D cationic conductor crystal@SWNT.

Nanocomposites consisting of one-dimensional (1D) crystals of the cationic conductors CuI, CuBr and AgBr inside single-walled carbon nanotubes, mainly (n, 0), were obtained using the capillary technique. 1D crystal structure models were proposed based on the high resolution transmission electron microscopy performed on a FEI Titan 80-300 at 80 kV with aberration correction. According to the models and image simulations there are two modifications of 1D crystal: hexagonal close-packed bromine (iodine) anion sublattice (growth direction <001>) and 1D crystal cubic structure (growth direction <112>) compressed transversely to the nanotube (D(m) ∼1.33 nm) axis. Tentatively this kind of 1D crystal can be considered as monoclinic. One modification of the anion sublattice reversibly transforms into the other inside the nanotube, probably initiated by electron beam heating. As demonstrated by micrographs, copper or silver cations can occupy octahedral positions or are statistically distributed across two tetrahedral positions. A 1DAgBr@SWNT (18, 0; 19, 0) pseudoperiodic 'lattice distortion' is revealed resulting from convolution of the nanotube wall function image with 1D cubic crystal function image.

The structure of 1D CuI crystals inside SWNTs.

Nanocomposites consisting of one-dimensional CuI crystals inside single-walled carbon nanotubes were obtained using the capillary technique. high-resolution transmission electron microscopy investigations of the atomic structure of the encapsulated 1D CuI crystals revealed two types of 1D CuI crystals with growth direction <001> and <110> relative to the bulk hexagonal CuI structure. Atomic structure models were proposed based on the high-resolution transmission electron microscopy images. According to the proposed models and image simulations, the main contrast in the 1D crystal images arises from the iodine atoms whereas copper atoms, with lower atomic number giving lower contrast, are thought to be statistically distributed.

[Functional-anatomical prerequisites of revascularization of the femoro-popliteal arterial segment].

Improved results of surgical treatment of patients with critical ischemia of lower extremities can be obtained by using the collateral bed. The condition of the profound femoral artery and the popliteal artery, especially in the zone of its trifurcation, is of the greatest significance for the decision on the volume of surgery. The carrying capacity of the collateral bed of the profound femoral artery in occlusion of the femoral artery was on average 284 ml/min. A positive prognostic criterion of recovered circulation in the extremity using the profound femoral artery is preservation of the patent trifurcation of the popliteal artery and/or the anterior tibial artery. The blood flow volume along the profound femoral artery under the given functional-anatomical conditions should be not less than 150 ml/min. Semiclosed loop endarterectomy of the superficial femoral and popliteal arteries with multilevel lesions of the lower extremity arteries allows the main zones of the collateral bed of the femoro-popliteal-tibial segment to be included in the blood flow.

[Multilevel revascularization of the lower extremities using loop endarterectomy].

Results of 91 reconstructions of the ilio-femoro-popliteal segment in patients with multilevel injuries of the lower extremity arteries were analyzed. In 42 of the operations a method of operations associated with loop endarterectomy was used. The first stage in all the patients consisted of iliac deep femoral reconstructions or semi-closed loop endarterectomy from iliac arteries in order for inclusion in blood flow of the profound femoral artery. In the presence of the volumetric blood flow along the profound femoral artery less than 150 ml/min after the first stage of revascularization the operation volume was extended at the expense of the femoro-distal reconstructions and/or semi-closed loop endarterectomy from the femoral and popliteal arteries. It was found that revascularization of the ilio-femoral segment in combination with desobliteration of the popliteal artery allowed performing two-level reconstructions with little time and material costs followed by primary positive results in 92.9% of cases.

[Quality of life of patients with atherosclerotic lesion of lower extremity arteries as dependent on individual and typological properties of the patient personality]. / Kachestvo zhizni bol'nykh s ateroskleroticheskim porazheniem arterii nizhnikh konechnostei v zavisimosti ot individual'no-tipologicheskikh svoistv lichnosti patsienta.

Twenty men with atherosclerotic lesion of lower extremity arteries verified by contrast angiography and ultrasound Doppler were examined. The patients' age varied from 36 to 69 years (mean 57 years). Six patients had IIB ischemia, 13 presented with degree III and one patient had degree IV ischemia according to the R. Fontaine classification modified by A. V. Pokrovsky. The MOS SF = 36 questionnaire was used to estimate the quality of life of all the patients. The individual typological properties of the personality were defined using the psychodiagnostic test (PDT). A significant decrease of the patients' quality of life was revealed according to the scales: physical function, physical role, physical pain, general health condition. A correlation was recorded between the patient's age and the parameters of the "physical function scale" (r=-0.63; p<0.005). The individual typological properties of the personality exert an effect on five of the eight SF = 36 scales. A feedback was discovered between neurotism and mental health (r=-0.455; P<0.05), conscientiousness and the physical role (r=-0,487; p<0.05); a direct relationship was found between disinhibition and physical pain (r=0.451; p<0.05), general activity and physical pain (r=0.535; p<0.05). An indistinctly pronounced feed back manifested itself between the "neurotism" and "physical pain" scales (r=-0.409), "psychotism" end the "physical role", (r=-0.437), "introversion" and "vitality" (r=-0.408), "femininity" and the "emotional role" (r=-0.404), and a direct relationship was established between the scales "esthetic impressionability" and "vitality" (r=0.406).

[Tetrapyrroles: diversity, biosynthesis, biotechnology]. / Tetrapirroly: raznoobrazie, biosintez, biotekhnologiia.

Various aspects of metabolism and biotechnology of tetrapyrroles are reviewed. Structures and properties of newly discovered tetrapyrrole pigments, biosynthesis of most important functional tetrapyrroles (hemes, chlorophylls, corrinoids, siroheme, and methanogenesis factor F430), and biotechnological methods of production of porphyrins and corrinoids are discussed. 5-Aminolevulinic acid is shown to be a promising anticancer preparation.