New iodate fluoride Rb2Ce(IO3)5F with nonlinear optical properties

New noncentrosymmetric cerium(IV) iodate fluoride Rb2Ce(IO3)5F was prepared employing a hydrothermal technique. The compound crystallizes in the Cmc21 space group (#36) with cell parameters a = 11.1518(6) Å, b = 8.1187(4) Å and c = 17.1581(10) Å. The crystal structure of Rb2Ce(IO3)5F consists of layers composed of 8-vertex CeO7F and 7-vertex Rb(1)O7 and Rb(2)O6F polyhedra interconnected by I(2)O3 groups. These layers are stitched by trigonal pyramidal I(1)O3 and I(3)O3 groups into a 3D framework. Synthesized iodate fluoride is thermally stable in air up to 430 °C. According to DFT calculations, Rb2Ce(IO3)5F is a direct-gap semiconductor with a band gap of ca. 2.33 eV. This value is in good agreement with an estimated optical gap value of 2.35 eV. The important feature of Rb2Ce(IO3)5F is the ability to generate a second optical harmonic signal comparable to that of KH2PO4.

Extending interstitial tetrelides into carbides: synthesis and crystal and electronic structures- of RE2Co2AlC (RE = La, Pr, Nd)

New quaternary compounds RE2Co2AlC (RE = La, Pr, Nd) of the filled W2CoB2 structure type were synthesized by the reaction of samples with the nominal composition RE40Co40Al20 (RE = La, Pr, Nd) and carbon. Single crystal X-ray diffraction data show that the RE2Co2AlC compounds crystallize in a body-centered orthorhombic space group Immm (oI12) with Z = 2 and a = 4.1841(11) Å, b = 6.1161(15) Å, c = 9.091(2) Å (La2Co2AlC); a = 4.1290(9) Å, b = 6.1152(18) Å, c = 8.844(3) Å (Pr2Co2AlC); a = 4.1168(15) Å, b = 6.1131(17) Å, c = 8.792(5) Å (Nd2Co2AlC) and are isotypic to the recently reported Nd2Co2SiC. The structures can be described as interstitial carbides of the W2CoB2 structure type with carbon atoms fully occupying the octahedral voids, which leads to the anisotropic expansion of the unit cell, more pronounced along the b-axis. Electronic structure calculations predict the RE2Co2AlC (RE = La, Pr, Nd) compounds to be metallic. The relative stability of the La2Co2AlX structures where X = C, O, Si, or a vacancy was investigated based on the bonding analysis, which emphasizes the important role that carbon plays in stabilizing the structural motif.

Polytypism of Ln(SeO3)(HSeO3)·2H2O compounds: synthesis and crystal structure of the first monoclinic modification of Nd(SeO3)(HSeO3)·2H2O, DFT calculations and order/disorder description

Compounds with the general formula Ln³⁺(SeO₃)(HSeO₃)·2H₂O, where Ln = Sm³⁺, Tb³⁺, Nd³⁺ and Lu³⁺, are characterized by orthorhombic symmetry with space group P2₁2₁2₁ and unit-cell parameters in the ranges a ∼ 6.473-6.999, b ∼ 6.845-7.101, c ∼ 16.242-16.426 Å. Light-purple irregularly shaped crystals of a new monoclinic polytype of neodymium selenite Nd(SeO₃)(HSeO₃)·2H₂O have been obtained during a mild-condition hydrothermal synthesis. The monoclinic unit-cell parameters are: a = 7.0815 (2), b = 6.6996 (2), c = 16.7734 (5) Å, β = 101.256 (1)°, V = 780.48 (6) ų; space group P2₁/c. The crystal structures of Nd(SeO₃)(HSeO₃)·2H₂O polymorphs show order-disorder (OD) character and can be described using the same OD groupoid family, more precisely a family of OD structures built up from two kinds of non-polar layers (category IV). The first monoclinic maximum degree order (MDO) structure (MDO1-polytype) with space group P2₁/c can be obtained when the inversion centre is active in the L_2n-type layers, while the second MDO structure (MDO2-polytype) is orthorhombic with space group P2₁2₁2₁ and can be obtained when the [2₁--] operation is active in the L_2n-type layers. The structural complexity parameters and DFT calculations of both polytypes show that the polytype structures are extremely close energy-wise and almost equally viable from the point of total energy of the structure.

Merging the AuCu3- and BaAl4-based structure motifs: flux-assisted synthesis, crystal, and electronic structure of Ca2Pt7XP4-δ phosphide platinides (X = Al, Ti, and Zn)

Three quaternary phosphide platinides, Ca₂Pt₇AlP_3.00(4), Ca₂Pt₇TiP_3.24(4), and Ca₂Pt₇ZnP_2.78(2), were synthesized by a high-temperature technique using lead as a flux. According to the single-crystal diffraction data, they are isotypic and crystallize in the tetragonal space group I4/mmm with Z = 2 (Ca₂Pt₇AlP_3.00(4): a = 3.9893(6) Å, c = 26.832(5) Å; Ca₂Pt₇TiP_3.24(4): a = 3.99610(10) Å, c = 26.9074(17) Å; Ca₂Pt₇ZnP_2.78(2): a = 4.0020(2) Å, c = 26.5549(17) Å) and thus represent first europium-free compounds of the Eu₂Pt₇AlP_2.95 structure type. Their structures can be described as an intergrowth of the AuCu₃- and CaBe₂Ge₂-type blocks. DFT calculations predict metallic conductivity and non-magnetic state for all three compounds. Bonding analysis based on the Bader charge distribution and ELF topology reveals a combination of localized covalent and ionic interactions in the CaBe₂Ge₂-type fragments and complex pattern of pairwise, multi-center, and ionic interactions in the AuCu₃-type fragments that closely reproduces bonding in the parent Pt₃X (X = Al, Ti, Zn) binary intermetallics.

Metal-Rich Phosphides Obtained from the Lead Flux: Synthesis, Crystal, and Electronic Structure of Sr5Pt12P9 and BaPt3P2

Using a high-temperature ampoule technique and lead metal as a flux, we have grown single crystals and determined crystal structures from single-crystal X-ray diffraction data of two metal-rich phosphides, Sr₅Pt₁₂P₉ (P 2₁/m, a = 6.1472(3) Å, b = 25.1713(13) Å, c = 6.4635(3) Å, β = 99.604(2)°, Z = 2, R₁ = 0.0326, wR₂ = 0.0786) and BaPt₃P₂ (P 2₁2₁2₁, a = 6.3605(6) Å, b = 6.8541(7) Å, c = 11.3493(12) Å, Z = 4, R₁ = 0.0231, wR₂ = 0.0501). Both compounds belong to their own structure types and feature 3D networks of Pt and P atoms, with the channels occupied by alkaline earth metal cations. Density functional theory calculations reveal Sr₅Pt₁₂P₉ to be a metal, while BaPt₃P₂ is a narrow-gap semiconductor with a band gap of 0.24 eV. Bonding analysis shows that both compounds feature networks of prominent covalent localized Pt-P bonds, responsible for their structural stability, as well as additional weaker and, likely, less localized Pt-Pt interactions.

[Kinesiophobia in patients requiring hip and knee endoprosthetics: severity and provoking factors]

Kinesiophobia (KP), or an irrational fear of physical activity, significantly hinders the active rehabilitation of patients with joint pathology.

PURPOSE OF THE STUDY

To study the severity and risk factors of KP in patients requiring total hip and knee endoprosthetics (EP).

MATERIAL AND METHODS

We examined 50 patients requiring total EP of the hip and knee joints. Pain syndrome was assessed in the preoperative and early postoperative periods in all patients using a visual analog scale, as well as the levels of kinesiophobia, anxiety, and depression using the Hospital Anxiety and Depression Scale and the Tampa Scale for Kinesiophobia (TSK). Quality of patients life was studied in the preoperative period (RAND SF36 questionnaire).

RESULTS

In the majority of cases, both before and after EP, the level of KP corresponded to an average degree of severity. Both in the preoperative and in the early postoperative periods, not a single case of the absence of KP was detected (≤17 points according to the TSK); at the same time, a very high level of KP (≥55 points according to TSK) was also rarely recorded - in 3 patients in the postoperative period after EP of the hip joint. KP level significantly correlated with the duration of the pain syndrome, while the mental component of the KP, in addition to the duration of the pain syndrome, was influenced by the social status: in patients who had a steady job, the psychological component of the KP was expressed in a less degree. KP level was negatively correlated with such indicators of quality of life as vitality and physical functioning. In addition, the physical component of the KP significantly correlated with the pain intensity, the mental component - with role-playing behavior.

CONCLUSION

Early detection of KP and timely correction of distorted ideas about physical activity are necessary for successful rehabilitation of patients requiring total joint endoprosthetics of the lower limb.

Intermetallic Compound Re2Ga9Ge with Re- and Ge-Embedded Gallium Clusters: Synthesis, Crystal Structure, Chemical Bonding, and Physical Properties

Transition metal-based endohedral cluster intermetallic compounds are interesting electron phases, which frequently exhibit superconductivity with a peculiar interplay between the critical temperature and valence electron count. We present a new Re-based endohedral gallium cluster compound, Re₂Ga₉Ge. Its unique crystal structure (P4₂/mmc space group, a = 8.0452(3) Å, c = 6.7132(2) Å) is built by two types of gallium polyhedra: monocapped Archimedean antiprisms centered by rhenium atoms and tetrahedra containing a main-group element inside. The analysis of chemical bonding shows the presence of localized pairwise interactions between the p-block elements and the formation of multicenter bonds with the participation of d-orbitals of rhenium. In the electronic band structure, the Fermi level is located in a narrow pseudogap indicating the optimum band filling and thus explaining the virtual absence of a homogeneity range. The compound exhibits Pauli paramagnetism and metallic properties with unexpectedly low thermal conductivity. A sharp anomaly observed on the magnetic susceptibility and resistivity curves presumably indicates the electronic phase transition accompanied by charge ordering at the characteristic temperature of T * = 271 K in zero magnetic field.

Synthesis and supramolecular organization of the iodide and triiodides of a polycyclic adamantane-based diammonium cation: the effects of hydrogen bonds and weak I⋯I interactions

Adamantane-like divalent building blocks and iodide or polyiodide anions combine into supramolecular architectures with the help of various noncovalent forces ranging from strong hydrogen bonds to secondary and weak I⋯I interactions.

Nickel - p-block metal mixed chalcogenides based on AuCu3-type fragments: iodine-assisted synthesis as a way of obtaining new structures

Two new mixed nickel-gallium chalcogenides, Ni9.39Ga2S2 and Ni5.80GaTe2, and a new mixed nickel-indium telluride, Ni5.78InTe2, have been synthesized by a high-temperature ampoule route with the addition of iodine, and characterized from single-crystal or powder diffraction data. They belong to the relatively uncommon Ni7-xMQ2/Ni10-xM2Q2 type of structures (M = Ge, Sn, Sb, In), and are built from p-block metal-centered nickel cuboctahedra, alternating along the c axis with defective Cu2Sb-type nickel-chalcogen ones. Both tellurium-containing compounds show a small degree of orthorhombic distortion with respect to the idealized tetragonal structure, only detectable in the powder diffraction data. No phase transition to the tetragonal structure was detected for Ni5.80GaTe2 by the in situ powder diffraction measurements from room temperature to 550 °C. DFT calculations show close relationships of electronic structures of these ternary compounds to their parent intermetallics, Ni3M (M = Ga, In). Metallic conductivity and paramagnetic properties are predicted for all three with the latter confirmed by magnetic measurements. The bonding patterns, investigated via the ELF topological analysis, show multi-centered nickel - p-block metal bonds in the AuCu3-type fragments and pairwise covalent interactions in the nickel-chalcogen fragments. Both Ni7-xMTe2 compounds showed no structural or compositional changes upon high-temperature mid-pressure hydrogenation.

Electron-Precise Semiconducting ReGa2Ge: Extending the IrIn3 Structure Type to Group 7 of the Periodic Table

Intermetallic compounds with semiconducting properties are rare, but they give rise to advanced materials for energy conversion and saving applications. Here, we present ReGa₂Ge, a new electron-precise narrow-gap intermetallic semiconductor. The compound crystallizes in the IrIn₃ structure type (space group P4₂/mnm, a = 6.5734(3) Å, c = 6.7450(8) Å, and Z = 4), where Re atoms occupy the Ir site, while Ga and Ge jointly populate the In sites. ^69,71Ga nuclear quadrupole resonance spectroscopy indicates nonstatistical partially ordered distribution of Ga and Ge over two available crystallographic sites; however, the Ga:Ge ratio is exactly 2:1 without noticeable homogeneity range. The stoichiometry of ReGa₂Ge ensures its precise valence electron count, which is 17 e^- per formula unit. Accordingly, a narrow energy gap opens up at the Fermi energy in the electronic structure. Electrical resistivity, Seebeck coefficient, and thermal conductivity are in agreement with the semiconducting behavior deduced from the electronic structure calculations and point to prospective thermoelectric properties at high temperatures. Bonding analysis reveals dominant covalency in Re-E (E = Ga, Ge) and Re-Re interactions.

Synthesis, electronic structure and physical properties of two new layered compounds, EuFAgSe and EuFAg1-δTe, featuring the active redox pair Eu2+/Ag. Dalton Trans 2020;49:7426-7435. [PMID: 32432284 DOI: 10.1039/d0dt01504k]

Systematic studies of the ZrCuSiAs (also LaOAgS or 1111) structure type resulted in the synthesis of two new fluoride chalcogenides, EuFAgSe and EuFAg1-δTe, whereas their sulfide analog, EuFAgS, could not be obtained. Both new compounds are tetragonal, P4/nmm, with cell parameters a = 4.1542(1) Å, c = 9.2182(1) Å for the selenide and a = 4.3255(1) Å, c = 9.5486(1) Å for the telluride. Rietveld refinement reveals a significant silver deficiency in the telluride (δ = 0.05), while the selenide is nearly stoichiometric. Both compounds are semiconductors as shown by diffuse reflectance spectroscopy and confirmed by density-functional calculations of the band structure. Magnetism of both compounds is predominantly driven by Eu2+, as indicated by magnetic susceptibility measurements and corroborated by 151Eu Mössbauer spectroscopy. EuFAg1-δTe and EuFAgSe are paramagnetic down to 1.8 K.

EuNi2P4, the first magnetic unconventional clathrate prepared via a mechanochemically assisted route

The first magnetic unconventional clathrate EuNi₂P₄ has been prepared and its thermodynamic properties have been investigated.

Synthesis, crystal and electronic structures of Pt-rich phosphides EuPt3P and EuPt6P2

Two new ternary Pt-rich phosphides, EuPt6P2 and EuPt3P, have been prepared via a two-step solid state reaction. Their crystal structures have been determined from powder XRD data. EuPt6P2 is isostructural to SrPt6P2 (cubic, Pa3[combining macron], a = 8.4603(1) Å); its crystal structure comprises corner-sharing Pt6P trigonal prisms hosting Eu2+ cations in the cuboctahedral voids of the framework. EuPt3P is isostructural to the SrPt3P anti-perovskite (P4/nmm, a = 5.7452(1) Å and c = 5.4212(1) Å). Magnetization measurements reveal the magnetic response caused by the Eu2+(4f7) cations. EuPt6P2 is paramagnetic exhibiting no phase transitions down to 1.8 K, whereas EuPt3P orders ferromagnetically below 19 K. Similar to SrPt6P2 and SrPt3P, the new compounds are metallic with states near the Fermi level predominantly formed by the 5d orbitals of Pt.

Tennantite: multi-temperature crystal structure, phase transition and electronic structure of synthetic Cu12As4S13

The structure of synthetic tennantite Cu₁₂As₄S₁₃ was investigated at various temperatures in the 90-293 K range. It crystallizes in space group I{\overline 4}3m. No structural transformation was observed in this temperature range. The structures were refined in anharmonic approximation for atomic displacements and electron density maps were refined using the maximum entropy method. Both approaches indicate a noticeable static disorder of the copper atoms in the triangular sulfur coordination and neighbouring site at high temperatures, whereas these split copper sites are well defined at lower temperatures. One particle potential is used to describe the behaviour of atoms at these copper sites. Such behaviour may be the structural reason for changes in magnetic properties.

ReGaGe2: an intermetallic compound with semiconducting properties and localized bonding

ReGaGe2 is a new member of the family of intermetallic compounds with non-metallic properties. It displays highly localized covalent bonding patterns. Its electronic structure is governed by mixing of Re d orbitals with the s and p orbitals of Ga and Ge and features the Fermi level falling into the opened band gap, ensuring experimentally confirmed semiconducting properties.

Layered Compounds BaFMgPn (Pn = P, As, Sb, and Bi), Transition-Metal-Free Representatives of the 1111 Structure Type

Four new transition metal-free pnictide representatives of the LaOAgS structure type were predicted by DFT calculations and found in the BaFMgPn (Pn = P, As, Sb and Bi) family. The compounds adopt the tetragonal space group P4 /nmm with the unit cell parameters a/ c 4.3097(1) Å/9.5032(1) Å, 4.3855(1) Å/9.5918(1) Å, 4.5733(1) Å/9.8184(1) Å, and 4.6359(1) Å/9.8599(1) Å, respectively. According to the DFT calculations, these new compounds are semiconductors with band gaps steadily decreasing from Pn = P ( ca. 2 eV) to Pn = Bi ( ca. 1 eV). The corresponding strontium fluoride and rare-earth oxide analogs are unlikely to exist and have not been observed yet. The trends of the stability within 1111 and structurally and/or chemically related compounds based on a combined consideration of geometry and DFT calculations are discussed.

ReGa0.4Ge0.6: Intermetallic Compound with Pronounced Covalency in the Bonding Pattern

We report synthesis, crystal and electronic structure, and transport properties of new intermetallic compound ReGa_0.4Ge_0.6, which was obtained by two-step ampule method from the elements. ReGa_0.4Ge_0.6 crystallizes in its own structure type (space group I4/ mmm, a = 2.89222(3) Å, c = 15.1663(3) Å, and Z = 4) which can be described as a sequential alternation of blocks of rhenium atoms and blocks of gallium and germanium atoms. Chemical bonding analysis reveals pronounced covalency of Re-Re, Re-E, and E-E (E = Ga and Ge) interactions and an interesting bonding pattern that includes many variations of localized bonding within a single compound, including pairwise homo- and heterometallic bonding, three-centered homometallic and four-centered bonding, and possibly even more delocalized bonding, which is not often encountered in such a simple intermetallic compound. Metallic behavior is confirmed by electronic structure calculations and by measurements of electrical resistivity.

From Isolated Anions to Polymer Structures through Linking with I2: Synthesis, Structure, and Properties of Two Complex Bismuth(III) Iodine Iodides

We report the synthesis, crystal structures, and optical properties of two new compounds, K₁₈Bi₈I₄₂(I₂)_0.5·14H₂O (1) and (NH₄)₇Bi₃I₁₆(I₂)_0.5·4.5H₂O (2), as well as the electronic structure of the latter. They crystallize in tetragonal space group P4/ mmm with the unit cell parameters a = 12.974(1) and c = 20.821(3) Å for 1 and a = 13.061(3) and c = 15.162(7) Å for 2. Though 1 and 2 are not isomorphous, their crystal structures display the same structural organization; namely, the BiI₆ octahedra are linked by I₂ units to form disordered layers in 1 and perfectly ordered chains in 2. The I-I bond distances in the thus formed I-I-I-I linear links are not uniform; the central bond is only slightly longer than in a standalone I₂ molecule, whereas the peripheral bonds are significantly shorter than longer bonds typical for various polyiodides, which is confirmed by Raman spectroscopy. The analysis of the electronic structure shows that the atoms forming the I-I-I-I subunits transfer electron density from their occupied 5p orbitals onto their vacant states as well as onto 6s orbitals of bismuth atoms that center the BiI₆ octahedra. This leads to low direct band gaps that were found to be 1.57 and 1.27 eV for 1 and 2, respectively, by optical absorption spectroscopy. Luminescent radiative relaxation was observed in the near-IR region with emission maxima of 1.39 and 1.24 eV for 1 and 2, respectively, in good agreement with the band structure, despite the strong quenching propensity of I₂ moieties.

[Conservative treatment of chronic diseases of lower limb veins: major risks of poor patient compliance]

Presented herein are the results of the Russian part of the International Research Programme 'VEIN ACT' aimed at studying approaches to conservative treatment of chronic vein diseases in the Russian Federation, assessing its efficacy and safety, as well as monitoring the patient compliance. Also discussed are the regimen and results of conservative therapy, depending on patients' gender, age and body mass index, as well as the level of adherence to various methods of treatment in the cohorts concerned. High efficacy of conservative therapy in all patients was confirmed. However, the regimen of drug therapy needs to be adjusted depending on the disease severity, especially in patients of a more advanced age and those with obesity. The lowest patient compliance was observed in relation to compression treatment. The existing situation may be improved by be means of appropriate recommendations and a possible decrease of the level and degree of compression. This should of course be done carefully and attentively, with obligatorily taking into consideration the patients' age and body mass index.

Structural and Thermodynamic Stability of the "1111" Structure Type: A Case Study of the EuFZnPn Series

Two new compounds with the LaOAgS structure, EuFZnAs (1) and EuFZnSb (2), were obtained via solid state reaction. Both compounds are tetragonal (P4/nmm) with the cell parameters a = 4.1000(1) Å and c = 9.0811(1) Å for 1 and a = 4.2852(1)Å and c = 9.4238(1)Å for 2. The absence of their phosphide analog can be explained based on crystal chemical considerations as well as on quantum-chemical estimates of their thermodynamic stability with respect to EuF₂ and EuZn₂Pn₂. The magnetic response of 1 and 2 is ascribed to the presence of Eu²⁺ ions. Both compounds are paramagnetic down to low temperatures, where they order antiferromagnetically at ∼5 K and ∼3 K, respectively. They are narrow-gap semiconductors, and EuFZnSb demonstrates a relatively high value of the Seebeck coefficient.

Iodobismuthates Containing One-Dimensional BiI4(-) Anions as Prospective Light-Harvesting Materials: Synthesis, Crystal and Electronic Structure, and Optical Properties

Four iodobismuthates, LiBiI4·5H2O (1), MgBi2I8·8H2O (2), MnBi2I8·8H2O (3), and KBiI4·H2O (4), were prepared by a facile solution route and revealed thermal stability in air up to 120 °C. Crystal structures of compounds 1-4 were solved by a single crystal X-ray diffraction method. 1: space group C2/c, a = 12.535(2), b = 16.0294(18), c = 7.6214(9) Å, β = 107.189(11)°, Z = 4, R = 0.029. 2: space group P21/c, a = 7.559(2), b = 13.1225(15), c = 13.927(4) Å, β = 97.14(3)°, Z = 2, R = 0.031. 3: space group P21/c, a = 7.606(3), b = 13.137(3), c = 14.026(5) Å, β = 97.14(3)°, Z = 2, R = 0.056. 4: space group P21/n, a = 7.9050(16), b = 7.7718(16), c = 18.233(4) Å, β = 97.45(3)°, Z = 4, R = 0.043. All solid state structures feature one-dimensional (BiI4)(-) anionic chains built of [BiI6] octahedra that share two opposite edges in such a fashion that two iodine atoms in cis-positions remain terminal. The calculated electronic structures and observed optical properties confirmed that compounds 1-4 are semiconductors with direct band gaps of 1.70-1.76 eV, which correspond to their intense red color. It was shown that the cations do not affect the optical properties, and the optical absorption is primarily associated with the charge transfer from the I 5p orbitals at the top of the valence band to the Bi 6p orbitals at the bottom of the conduction band. Based on their properties and facile synthesis, the title compounds are proposed as promising light-harvesting materials for all-solid solar cells.

Kinematic constituents of the extreme head turn of Strix aluco estimated by means of CT-scanning

To analyze extreme sideways turn of the head in owls, a total fresh specimen of Strix aluco was frozen in respective posture and CT-scanned. The maximum turn to one side was found to be 360°, provided that the head is drawn into the shoulders. 160° of this full turn are ensured by the neck axial rotation (this includes ~90° twist of the head relative to epistropheus and, posterior to it, less than 15° per every cervical joint), and the rest 200° are ensured by combination of dorsal and lateral flexion. The 15° limit is overcome in five joints in respect of dorsiflexion, and in six joints in respect of lateral flexion. So large a degree of lateral mobility is unusual among birds, and is appreciated as a crucial adaptation to extreme head turning.

A novel quasi-one-dimensional topological insulator in bismuth iodide β-Bi4I4

Recent progress in the field of topological states of matter has largely been initiated by the discovery of bismuth and antimony chalcogenide bulk topological insulators (TIs; refs ,,,), followed by closely related ternary compounds and predictions of several weak TIs (refs ,,). However, both the conceptual richness of Z2 classification of TIs as well as their structural and compositional diversity are far from being fully exploited. Here, a new Z2 topological insulator is theoretically predicted and experimentally confirmed in the β-phase of quasi-one-dimensional bismuth iodide Bi4I4. The electronic structure of β-Bi4I4, characterized by Z2 invariants (1;110), is in proximity of both the weak TI phase (0;001) and the trivial insulator phase (0;000). Our angle-resolved photoemission spectroscopy measurements performed on the (001) surface reveal a highly anisotropic band-crossing feature located at the  point of the surface Brillouin zone and showing no dispersion with the photon energy, thus being fully consistent with the theoretical prediction.

Fluxes of energy, H2O, and CO2 between the atmosphere and the monsoon tropical forest in Southern Vietnam

The 2.5-year dynamics of heat, water and carbon dioxide fluxes in the tropical monsoon semi-evergreen forest in Southern Vietnam obtained by means of continuous eddy covariance observations using standard procedures of FLUXNET global network are analyzed. The features of wet seasons during the measurement period were close to long-term average ones, but dry seasons had a great heterogeneity. The maximal duration of the period with little precipitation was 4 months. The annual radiation balance in the south of Vietnam exceeded the balance at all stations of FLUXNET in tropical forests, except one. Annual evapotranspiration in monsoon forest of south of Vietnam is approximately equal to the evaporation of the rain forests of Central Amazonia. During the wet season evapotranspiration spent 80% of the radiation balance, and in the driest months this value decreased to 50%. In the dry season reduction of evapotranspiration and gross primary production was relatively small due to photosynthesizing trees of 2-4 canopy sub-layers. For the first time a large net sink of carbon dioxide from the atmosphere in the monsoon forest ecosystem was identified.

[Melatonin in the correction of sleep in post-stroke patients]

AIM

To assess an effect of melatonin on quality of life and effectiveness of rehabilitation in patients with ischemic stroke (IS) suffered from insomnia due to sleep initiation disturbance.

MATERIAL AND METHODS

Sixty post-stroke patients with insomnia were stratified into two groups matched for characteristics assessed in the study. Patients of the main group received melatonin during 21 days. In the first three days after admission and 21 days after the first examination, we administered the MMSE, the Rankin scale, FOSQ, NIHSS, EuroQol, the Epworth sleepiness scale (ESS) and used instrumental methods of examination (computed and magnetic-resonance tomography, electroencephalography, polysomnography).

RESULTS

After 3 weeks, there was a reduction (p<0.05) in ESS scores in the main group compared to the control group (5.7 and 10 scores, respectively). Significant between-group differences were identified for polysomnographic parameters: latency to sleep was 17.8 min in the main group and 20.5 min in the control group (p<0.05), the number of microactivations was 15 and 18, respectively (p<0.05). There was a trend towards more rapid recovery in the main group (on average 8.4 days) compared to the control group (10.2 days), but the differences did not reach the level of statistical significance p<0.05.

CONCLUSION

Melatonin reduced sleepiness (measured with the ESS), latency to sleep and number of wakings (microactivations) and was likely to promote the recovery in IS patients with insomnia due to sleep initiation disturbance.

Electrical muscle stimulation with Veinoplus® device in the treatment of venous ulcers

AIM

The aim of the study was to analyze the results of the electrical muscle stimulation (EMS) usage in patients with venous ulcers developed on top of a post-thrombotic syndrome (PTS).

METHODS

Sixty patients (60 legs) with active venous ulcer (C6EsAsdpPr according to CEAP classification) were divided into two groups. In addition to the background therapy consisting of a standardized compression with ULCER X and intake of micronized purified flavonoid fraction (MPFF 1000 mg daily), all the patients in the main group underwent EMS with Veinoplus® V.I. for at least 3 times a day. Follow-up examinations were performed on days 30, 60 and 90. These included pain severity assessment with 100-mm Visual Analogue Scale (VAS), disease severity measurement with VCSS (Venous Clinical Severity Score) and ankle circumference above malleolus, as well as recording number of healed venous ulcers.

RESULTS

At day 90 pain severity was reduced in both main and control groups. However, according to VAS pain reduction rates were significantly higher in patients of the main group (from 8.7 ± 0.6 to 1.9 ± 0.3 in the main group and 8.4 ± 0.6 to 3.9 ± 0.5 in the control group). At the end of the study, ankle circumference decreased from 270.9 ± 4.6 mm to 257.1 ± 4.2 mm in the main and from 269.7 ± 5.3 mm to 263.4 ± 5.2 in the control group. VCSS before treatment was 7.3 ± 0.6 in the main group and 6.8 ± 0.5 in the control group. By day 90 VCSS significantly decreased to 2.3 ± 0.4 and 4.6 ± 0.5 in the main and control groups respectively. Healing rates were significantly higher in the main group. On day 90, the number of open venous ulcers in the main group was 3 times lower than in the control group (4 vs. 12).

CONCLUSION

EMS demonstrated high efficacy and good tolerability and provided significant reduction in pain severity, VCSS score and ankle edema, as well as a 3-fold increase in the number of healed venous ulcers.

[Peculiarities of treatment of chronic venous diseases in Russia. Preliminary results of the "VEIN ACT Program"]

Presented herein are the results of the Russian part of the International Research Program "VEIN ACT" aimed at studying the structure of variants of conservative treatment for chronic venous diseases in the Russian Federation, assessing its efficacy and safety, as well as monitoring of patient compliance. The obtained findings demonstrated high popularity, among both physicians and patients, of phlebotrophic drugs, determining high patient's adherence thereto. Recommendations on correction of the lifestyle were complied with by more than 80% of patients, however frequently not in the full scale. Noted was sufficiently low compliance to compression therapy, manifesting itself as a decrease in the class of compression and irregular use thereof in more than 30% of patients. Usefulness of conservative therapy was objectively proved, consisting in satisfaction with treatment and a statistically significant decrease in severity of symptoms of chronic venous diseases in the overwhelming majority of patients.

[Treatment of sleep disorders in patients with mild cranial-brain injury in the early rehabilitation period]

OBJECTIVE

To study the effect of melatonin (melaxen) on sleep disorders in patients with mild cranial-brain injury (CBI) in the early rehabilitation period.

MATERIAL AND METHODS

Sixty patients were randomized to equal groups treated or not treated with melaxen. Along with neurological and somatic examination, polysomnography and scales for measurement depression and quality of life ( ESS, BDI, EuroQol etc) were used.

RESULTS AND CONCLUSION

Melatonin improved sleep (sleep latency, number of wakings per night etc) and decreased the severity of depression in the early rehabilitation period after mild CBI. Further research is needed to fully understand the effect of melatonin on sleep disorders in CBI, in particular in its later stages.

[Activation of neurohormonal system as an independent mechanism of heart remodeling in patients with chronic obstructive pulmonary disease]

AIM

To evaluate the contribution of activation of cytokines and renin-angiotensin-aldosterone system to heart remodeling in patients with chronic obstructive pulmonary disease in the course of a 2 year study and to estimate its relation to severe pulmonary hypertension.

MATERIALS AND METHODS

117 patients with COPD underwent measurement of TNFα, IL-6 levels and renin levels, spirometry and echocardiography (mean pressure in pulmonary artery, MPPA)). The data obtainedwere compared with the degree of remodeling of right and left ventricles. After 2 years 30 and 33 of the 63 patients were referred to groups with aggressive and moderate remodeling of the right ventricle respectively. Regressive analysis was used to detect predictors of aggressive remodeling.

RESULTS

Initial remodeling severity and rate showed stronger correlation with TNFα, IL-6 levels and renin levels than with MPPA. Multifactor analysis demonstrated that renin activity and creatinine level were the most reliable predictors of remodeling (p = 0.041 and 0.049 respectively).

CONCLUSION

Neurohormonal and imunno-inflammatory changes stimulate remodeling of right and left heart chambers. They independently affect myocardium and their influence is only partly mediated through exacerbation of pulmonary hypertension.

[Tropical monsoon forests of Vietnam (results of 20 years of phytoecological research)]

This study was carried out during the period 1989-2011. The following areas were included: Vietnam, Laos, Cambodia, Indonesia, and Malaysia. Climax tropical forest and anthropogenically transformed ecosystems, including those damaged by the chemical warfare program of the United States in Vietnam, were investigated. Some regularities in the structure dynamics and functioning of forests ecosystems under a tropical monsoon climate have been revealed. The principles of classification of tropical forests have been elaborated. The major results of investigation of the tropical monsoon forests in Vietnam are given.

[The combined drug ascoril in the treatment of patients with chronic obstructive pulmonary disease concurrent with coronary heart disease]

AIM

To evaluate the clinical efficacy of the combined drug ascoril (Glenmark, India) in patients with grade I-Ii chronic obstructive pulmonary disease (COPD) concurrent with coronary heart disease (CHD).

SUBJECTS AND METHODS

Sixty patients, including 12 (20%) women and 48 (80%) men, aged 43 to 68 years (mean age 55.1 +9.9 years), with COPD were examined. The patients were divided into 2 groups. Group 1 used the combined broncholytic and expectorant drug ascoril and Group 2 took mucolytic agent ambroxol. The follow-up period was 7 days.

RESULTS

On day 2 of ascoril treatment, all the patients showed a significant reduction in the intensity of cough that was completely relieved in 26 (87%) patients by treatment day 7. Prior to ascoril treatment, heart rate (HR) was 64.4+/-5.5 beats/min. A significant increase in HR to 72.7+/-10.1 beats/min was observed 20 min after the first drug intake (p < 0.05) and a decrease to 68.6+/-10.5 beats/min was seen after 60 min. On treatment day 7, HR was 63.0+/-6.5 beats/min, which was similar to that before ascoril treatment (p = 0.6).

CONCLUSION

In the patients with COPD concurrent with CHD, the combined drug ascoril exerts broncholytic and expectorant effects, with no pronounced negative action on HR.

[Chronic venous oedema (C3 according to CEAP): new international guidelines and consensuses]

The review based on analysing the results of epidemiological studies, as well as international guidelines and consensuses published in 2011-2012 reflects the present-day data concerning prevalence, principles of diagnosis and treatment of chronic venous oedema. This is followed by determining the role of compression and drug therapy in treatment thereof from the positions of evidence-based medicine.

[Bioflavonoids and their significance in angiology: focus on diosmin]

The article deals with historical information dedicated to the discovery of bioflavonoids and their effect on the human cardiovascular system, also considering the modern classification of phlebotrophic agents, followed by generalization and analysis of their mechanisms of action, as well as detailed discussion of different forms of diosmin. Summing up contains generalization of the Russian, European, and American guidelines on using phlebotrophic drugs for various forms and stages of chronic venous diseases.

Electromuscular stimulation with VEINOPLUS® for the treatment of chronic venous edema

AIM

Electromuscular stimulation (EMS) with VEINOPLUS® has recently emerged as a new technique to activate the calf muscle pump, improving the symptoms of venous disease. The aim of the study was to evaluate efficacy of EMS and its impact on evening edema, venous pain, venous outflow and patients quality of life.

METHODS

Thirty patients (32 legs) aged 19-50 (mean 45.2±1.3) classified CEAP C3 with chronic evening venous edema took part in the study (22 limbs: C3, S, Ep, Asp, Pr and 10 limbs: C3, S, Es, Aspd, Pr). All patients were treated with CE-registered VEINOPLUS® neuromuscular stimulator for 30 days. 3 sessions per day (each session lasted for 20 minutes) for the first 10 days, the next 10 days 2 sessions per day and one session per day for the last 10 days. The main evaluated criteria for venous edema was the circumference of the supramaleoal shin segment, measured twice with a tape measure; in the evening the day before and then 5 days after the treatment. All measurements were taken during the interval between 6 and 8 o'clock P.M. All the patients were asked to evaluate venous pain using the Visual Analog Scale, and to fill in a CIVIQ questionnaire (validated for Russian patients) for the Quality Of Life (QOL) measurement. Also venous refilling time (RT) was measured by digital PPG. That was also made twice - before the treatment and in 35 days after the treatment. No other treatments were used.

RESULTS

The EMS treatment was well tolerated by patients. There were no drop outs and patients had no need to change their lifestyles. After the treatment, total or partial reduction of evening edema was shown in 93.8% of limbs, the circumference of the lower leg diminished by 20.3mm (P<0.001), the number of painful legs reduced from 28 to 12 and the severity score of venous pain was cut from 8.3 ±1.1 to 3.8 points ±0.9 (P<0.001), QOL improved significantly as the score dropped from 34.5 ±7.8 to 17.2 points ±4.6 (P<0.001) and RT increased from 17.3 ±0.9 to 21.5 seconds ±1.1 (P<0.001). Three months after VEINOPLUS® treatment, total remission of symptoms was observed in 50% of legs, despite there being no other treatments.

CONCLUSION

VEINOPLUS® stimulation is an effective and well-tolerated therapeutic method for the treatment of chronic venous disease. The introduced scheme of EMS application was shown to be useful for treatment of chronic edema, for reducing pain and improving quality of life. It can be used as an additional mean in treatment and to prevent symptoms of CVI. This study also reveals that stimulation of calf muscles with VEINOPLUS® can improve venous outflow and symptoms of CVI. This finding should be investigated and confirmed in further studies.

[Participation of leucocytes in pathogenesis of primary forms of lower limb chronic venous disease]

AIM

The purpose of the study was to test the hypothesis on participation of WBCs in damaging the venous wall in patients presenting with primary forms of lower limb chronic venous diseases LLCVD .

MATERIAL AND METHODS

The study included a total of fifteen consecutively selected patients (13 women and 2 men) diagnosed as having grade C2-C-4 LLCVD according to the CEAP classification. Static loading (30 minutes in the sitting position) was followed by simultaneous sampling of blood from the varicose vein of the cms and ulnar vein. The total blood count including determination of both the absolute values and percentage of blood formed elements was performed using the automated haematological counter «Advia 7» («Bayer», USA). The obtained findings were statistically processed using the Microsoft Office Excel software by means of the pared two-sample τ-test for the average values.

RESULTS

The number of leukocytes and their subpopulations in blood samples obtained from the crural varicose veins turned out to be significantly less as compared with that in blood sampled from the ulnar vein. Thus, blood sampled from the crural varicose veins demonstrated a decrease in the counts of WBC by 9.6% in fourteen (93.3%) patients, that of neutrophils by 4.9% in twelve (80%) patients, that of lymphocytes by 16,8% in fifteen (100%) patients, and that oi monocytes by 24% in twelve (80%) patients. The mentioned differences were statistically significant at a = 0.05. The eosinophilic counts in blood sampled from the upper and lower extremities appeared similar in 66.7% of the examined subjects. In 33.3% of cases the eosinophilic count in blood samples from crural varicose vein was by 16.7% lower than that for blood samples form the ulnar vein. No differences for the rest parameters of the clinical blood count were revealed.

CONCLUSION

The absolute lymphocytic count in the blood samples taken after the 30-minute static loading from the crural varicose veins was significantly lower as compared with that in blood sampled form the cubital vein. The counts for RBCs and blood platelets, as well as other qualitative haematological indices (haemoglobin, haematocrit, average volume of the RBC, erythrocytic diameter, etc.) in blood sampled form crural and ulnar veins in the same patient were identical, thus strongly suggesting the lack of either haemodynamic or haemorheological phenomena capable of leading to redistribution of the blood formed elements in varicose veins. Hence a decrease in the counts of leukocytes and their subpopulations in blood sampled from crural varicose veins might be associated with the «leukocytic trap» phenomenon.