Bulk ferromagnetism in cleavable van der Waals telluride NbFeTe2

A van der Waals telluride, NbFeTe2, has been synthesized using chemical vapor transport reactions. The optimized synthetic conditions yield high-quality single crystals with a novel monoclinic crystal structure. Monoclinic NbFeTe2 demonstrates a (100) cleavage plane, bulk ferromagnetism below 87 K, and a metallic ground state-the necessary prerequisites for needed spintronics technologies.

Interplay of two magnetic sublattices in related compounds Sm2Mn1-xGa6-yGey (x = 0.1-0.3, y = 0.6-1.0) and Sm4MnGa12-yGey (y = 3.0-3.5) with different ordering of empty and filled (Ga,Ge)6 octahedra

Single crystals of two new intermetallic phases Sm2Mn1-xGa6-yGey (x = 0.1-0.3, y = 0.6-1.0) and Sm4MnGa12-yGey (y = 3.0-3.5) were grown using a self-flux technique. According to single crystal X-ray diffraction data, Sm4MnGa12-yGey is characterised by the Y4PdGa12 structure type (a ∼ 8.65 Å; Im3̄m), while Sm2Mn1-xGa6-yGey formally adopts the K2PtCl6 structure type (a ∼ 8.71 Å; Fm3̄m). The general features of both compounds with rather similar crystal structures are represented by the alternation of empty and Mn-filled p-element octahedra, the order of which is determined by the Mn concentration. The diffraction data for Sm2Mn1-xGa6-yGey reveal a large concentration of Mn vacancies (x ∼ 0.3), which affects adjacent Ga/Ge atoms leading to their shift towards the vacancy. Both compounds demonstrate two ferromagnetic-like transitions and the presence of two interacting Mn and Sm magnetic sublattices. The Mn sublattice orders at TC1 of 143 K and 318 K, while the Sm one orders at lower temperatures at TC2 of 50 K and 280 K for Sm4MnGa8.6Ge3.4 and Sm2Mn0.74Ga5.1Ge0.9, respectively. The increase in Mn content not only increases the ordering temperatures, but also dramatically decreases the coercivity μ0HC from 230 mT to just 6.5 mT at 2 K. Despite the presence of two magnetically active sublattices in Sm2Mn0.74Ga5.1Ge0.9, the magnetic entropy change is quite low and only reaches 0.3 J kg-1 K-1 at T = 300 K and μ0H = 5 T, while the estimated relative cooling power (RCP) is about 36 J kg-1 at 5 T.

Impact of Ge Doping on Structural and Magnetic Ordering in RMnxGa3 and R4Mn1-xGa12-yGey (R = Tb, Dy; x ≤ 0.25, y ≈ 1.0-3.3)

Single crystals of RMnxGa3 and their new quaternary derivatives R4Mn1-xGa12-yGey (R = Tb, Dy, x ≤ 0.25, y ≈ 1.0-3.3) were grown from a Ga flux. The compounds are derivatives of cubic RGa3 phases, with Mn atoms filling the Ga6 voids. RMnxGa3 formally adopts a cubic ABO3 perovskite structure, in which the presence of Mn atoms results in a shift of the neighboring Ga atoms from their ideal position. A partial substitution of Ga by Ge leads to a higher Mn content, resulting in structural ordering of the latter and the formation of the superstructure phases R4Mn1-xGa12-yGey, which can be formally described in the Y4PdGa12 structure type. The presence of Mn vacancies, which was observed for R = Tb, and Ga/Ge mixing lead to a noticeable deviation from the idealized structure. The compounds contain two magnetic sublattices: the R sublattice, which orders antiferromagnetically near 20 K, and the Mn sublattice, which orders ferromagnetically at TC = 125-225 K with the Ge doping resulting in higher TC. The two sublattices are not independent, as the Mn sublattice induces partial ferromagnetic ordering of the rare earth atoms below TC, at least for the Ge-doped phases. Near TN, both magnetic susceptibility and heat capacity reveal complex behavior, indicating changes in magnetic structures below TN.

New Spin-Polarized Electron Source Based on Alkali Antimonide Photocathode

New spin-dependent photoemission properties of alkali antimonide semiconductor cathodes are predicted based on the detected optical spin orientation effect and DFT band structure calculations. Using these results, the Na_{2}KSb/Cs_{3}Sb heterostructure is designed as a spin-polarized electron source in combination with the Al_{0.11}Ga_{0.89}As target as a spin detector with spatial resolution. In the Na_{2}KSb/Cs_{3}Sb photocathode, spin-dependent photoemission properties were established through detection of a high degree of photoluminescence polarization and high polarization of the photoemitted electrons. It was found that the multi-alkali photocathode can provide electron beams with emittance very close to the limits imposed by the electron thermal energy. The vacuum tablet-type sources of spin-polarized electrons have been proposed for accelerators, which can exclude the construction of the photocathode growth chambers for photoinjectors.

Fe-Rich Ferromagnetic Cleavable Van der Waals Telluride Fe5AsTe2

Transition metal-based layered compounds with van der Waals gaps between the structural layers are a rich source of magnetic materials for spintronic applications. Bulk crystals can be cleaved, providing high-quality two-dimensional nanomaterials, which are promising for the manipulation of spins in spintronic devices and low power quantum logic interfaces. The layered van der Waals telluride Fe₅AsTe₂ can be synthesized by the high-temperature reaction of elements. In the crystal structure, Fe-rich structural layers with the composition of Fe_4.58(4)AsTe₂ are separated by the van der Waals gaps with no atoms in the interstitial region. Crystal growth employing chemical vapor transport reactions yields bulk cleavable crystals, which exhibit weak inherent ferromagnetism below the Curie temperature of T_C = 48 K. In the ordered state, the magnetization shows a dual-slope behavior in low magnetic fields, indicating the compensated or canted nature of magnetism. Magnetic susceptibility and magnetization measurements reveal perpendicular magnetic anisotropy. The large Rhodes-Wohlfarth ratio of 4.6 indicates the itinerant nature of ferromagnetism in Fe₅AsTe₂.

[Ultrastructure of neointima of native and artificial elements of the blood circulatory system]

OBJECTIVE

To compare the neointima structure in conduits for coronary bypass grafting, bioprosthetic heart valves, tissue-engineered vascular grafts, and metal stents.

MATERIAL AND METHODS

The objects of the study were the fragments of the human internal thoracic artery, experimental biodegradable vascular prostheses, leaflets of xenopericardial bioprostheses of heart valves, and fragments of stented vessels. Tissue samples were fixed in formalin and post-fixed in osmium tetroxide. After dehydration and epoxy resin embedding, the samples were ground and polished. Samples were counterstained with uranyl acetate and lead citrate and visualized by means of backscattered scanning electron microscopy.

RESULTS

Neointimal pattern in all samples was similar. Neointima was comprised of endothelial cells, smooth muscle cells, fibroblasts, and the extracellular matrix. Endothelial cells showed significant diversity both between different elements of the circulatory system and within the same tissue, having either elongated or polygonal shape. Adhesion of leukocytes testified to the endothelial cell activation. In the absence of inflammation in the superficial layer of the neointima, the arrangement of smooth muscle cells and extracellular matrix fibers was parallel to the endothelium. Clusters of foam cells were frequently detected around the neointimal layers with solid inclusions (metal stents or calcium deposits). Thickening of the neointima was accompanied by the presence of capillaries and capillary-like structures.

CONCLUSION

Neointima formation is a typical response to the damage inflicted to the elements of the circulatory system. Neointima underwent a constant remodeling characterized by an altered cellular composition, macrophage invasion, neovascularization, and calcification.

[Modern aspects of the treatment of submacular hemorrhages secondary to macular degeneration]

Age-related macular degeneration complicated by submacular hemorrhage if not treated timely leads to permanent loss of central vision. The basis of effective therapy is its early start, dislocation of blood from central parts of the retina and blockage of neovascularization. This review examines the current methods of treatment of submacular hemorrhages, anatomical and functional outcomes, risks of postoperative complications, as well as trends in the use of combined methods of surgical intervention.

Molecular and Supramolecular Structures of Triiodides and Polyiodobismuthates of Phenylenediammonium and Its N,N-dimethyl Derivative

Despite remarkable progress in photoconversion efficiency, the toxicity of lead-based hybrid perovskites remains an important issue hindering their applications in consumer optoelectronic devices, such as solar cells, LED displays, and photodetectors. For that reason, lead-free metal halide complexes have attracted great attention as alternative optoelectronic materials. In this work, we demonstrate that reactions of two aromatic diamines with iodine in hydroiodic acid produced phenylenediammonium (PDA) and N,N-dimethyl-phenylenediammonium (DMPDA) triiodides, PDA(I₃)₂⋅2H₂O and DMPDA(I₃)I, respectively. If the source of bismuth was added, they were converted into previously reported PDA(BiI₄)₂⋅I₂ and new (DMPDA)₂(BiI₆)(I₃)⋅2H₂O, having band gaps of 1.45 and 1.7 eV, respectively, which are in the optimal range for efficient solar light absorbers. All four compounds presented organic–inorganic hybrids, whose supramolecular structures were based on a variety of intermolecular forces, including (N)H⋅⋅⋅I and (N)H⋅⋅⋅O hydrogen bonds as well as I⋅⋅⋅I secondary and weak interactions. Details of their molecular and supramolecular structures are discussed based on single-crystal X-ray diffraction data, thermal analysis, and Raman and optical spectroscopy.

[Peculiarities of diagnosis and emergency surgical care in aorto-oesophageal fistula]

An aorto-oesophageal fistula is a rare but life-threatening pathological condition developing on the background of diseases of the aorta and oesophagus, as well as after surgical interventions on the aorta. The article deals with a clinical case report regarding management of a patient presenting with an aorto-oesophageal fistula resulting from a thoracic artery aneurysm. The main clinical manifestations of the diseases included dysphagia (due to oesophageal obstruction caused by thrombotic masses of the aneurysm) and the occurring gastrointestinal haemorrhage. Comprehensive instrumental diagnosis was performed using roentgen examination of the oesophagus, oesophagoscopy, and contrast-enhanced computed tomography of the chest. The obtained findings made it possible to objectively assess the patient's state, to carry out timely treatment in conditions of a surgical hospital, and to avoid severe complications.

Spectral detection of spin-polarized ultra low-energy electrons in semiconductor heterostructures

The circularly polarized cathodoluminescence (CL) technique has been used to study the free spin-polarized electron injection in semiconductor heterostructures with quantum wells (QWs). A polarized electron beam was created by the emission of optically oriented electrons from the p-GaAs(Cs,O) negative electron affinity (NEA) photocathode. The prepared beam was injected in a semiconductor QW target, which was activated by cesium and oxygen to reduce the work function. To study the spin-dependent injection, we developed a spin-detector prototype, which consists of a compact proximity focused vacuum tube with the source and target placed parallel to each other on the opposite ends of the vacuum tube (photodiode). The injection of polarized low-energy electrons into the target by varying the kinetic energy in the range of 0.5-5.0 eV and temperature in the range of 90-300 K was studied. The CL was polarized to 2 % by the injection of 20 % spin-polarized electron beam with the energy of 0.5 eV at room temperature. The asymmetry (Sherman function) of spin detection was estimated. It was shown that the dependence of the CL polarization degree on the injected electron energy is satisfactory described by the model that considers the electron spin relaxation in the heterostructure matrix and QWs. The results demonstrate that semiconductor detectors are promising for the spin-polarimetry applications based on the optical detection of free-electron spin polarization.

[Surgical treatment of a patient with saccular arterial aneurysm of the cavernous-ophthalmic segment]

Presented in the article are the results of surgical management of a patient with an extremely rare pathology - a saccular arterial aneurysm of the cavernous-ophthalmic segment of the left internal carotid artery. We performed multistage open surgical intervention in the following scope: osteoplastic pterional craniotomy on the left, creation of a wide-lumen anastomosis between the left external carotid artery and M2 segment of the left middle cerebral artery with the use of the radial artery, ligation of the cervical portion of the left internal carotid artery and clipping of its supraclinoid portion. The chosen surgical policy made it possible to create sufficient volumetric blood flow through the shunt, comparable to the blood flow through the internal carotid artery, which helped avoid ischaemic stroke after exclusion of the aneurysm from circulation. A conclusion was drawn on efficacy of this method of treatment.

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.

[Predictors of long-term complications after carotid endarterectomy]

AIM

To analyze the predictors of complications within 3 years after carotid endarterectomy (CEE).

MATERIAL AND METHODS

The study included 1035 patients after CEE for the period 2011-2016. Long-term follow-up period was 42.4±18.6 months (≈ 3.5 years). The endpoints were such unfavorable cardiovascular events as death, myocardial infarction, stroke/transient ischemic attack, redo revascularization. Statistical analysis was carried out by using of Statistica for Windows 8.0 software package (StatSoft Inc., USA). Stepwise logistic regression was applied to identify risk factors of adverse outcomes and death in long-term postoperative period.

RESULTS

Comprehensive analysis of numerous factors (anamnestic, instrumental-diagnostic, surgical) allowed us to identify predictors of long-term unfavorable outcomes in patients with occlusive-stenotic lesions of carotid arteries. Risk factors of long-term complications were SYNTAX score ≥33 (high risk), unstable plaque in the contralateral ICA, occlusion of contralateral ICA, LVEF <39%, ICA cross-clamping >40 min, previous CABG.

CONCLUSION

These data are extremely important and can be used to create prognostic models. The last ones are necessary to determine optimal treatment strategy in patients with occlusive-stenotic lesions of supra-aortic vessels.

Copper-Promoted C-Se Cross-Coupling of 2-Selenohydantoins with Arylboronic Acids in an Open Flask

The modification of Chan-Lam-Evans cross-coupling reaction for the selective Se-arylation of 2-selenohydantoins under base-free mild conditions via aryl boronic acids is described herein. This approach was used to synthesize novel 5-arylidene-3-substituted-2-(arylselanyl)-imidazoline-4-ones with high yields. The anticancer activity of the final compounds was evaluated in vitro against different cancer cells, and thus, the possibility of 5-arylidene-3-substituted-2-(arylselanyl)-imidazoline-4-ones successful application as cytotoxic agents was demonstrated.

[Surgical treatment of protoplasmic astrocytoma of sylvian aqueduct involving posterior part of the third ventricle]

It is presented case report of extremely rare pathology - protoplasmic astrocytoma of sylvian aqueduct involving posterior section of the third ventricle. The main principles of treatment were considered. Dynamics of neurological status was demonstrated. An effectiveness of treatment strategy was assessed.

Crystal Growth of Intermetallics from the Joint Flux: Exploratory Synthesis through the Control of Valence Electron Count

In this study, we modify the flux-growth method for the purpose of exploratory synthesis of ternary intermetallic compounds. Our concept is based on the assumption that valence electron count plays a crucial role in the stability of polar intermetallic compounds of different structure types. Control of the valence electron count parameter is made possible through the use of an excess of two metals having a different number of valence electrons. By gradually changing the ratio between these metals in the joint flux, we scan the gross number of valence electrons and explore the crystallization of new compounds. In the ternary system Re-Ga-Zn, we detect compounds belonging to three structure types, ReGa₅, PtHg₄, and V₈Ga₄₁, while gradually increasing the content of Zn metal in the flux. Two new compounds, ReGa₃Zn and Re₈Ga_{41- x}Zn _x with x = 21.2(5), are obtained in the form of high-quality single crystals, and the former compound shows the narrow-gap semiconducting behavior favorable for high thermoelectric performance.

[In-hospital outcomes of carotid endarterectomy depending on severity of contralateral lesion]

AIM

To compare in-hospital outcomes of carotid endarterectomy (CEE) in patients with different lesion of contralateral internal carotid artery (ICA).

MATERIAL AND METHODS

There were 730 CEE procedures in patients with bilateral ICA lesion for the period 2011-2016. All patients were divided into 4 groups depending on contralateral ICA stenosis grade: group 1 - stenosis up to 60% (42.6%, n=311); group 2 - 60-90% (18.7%, n=137); group 3 - 90-99% (25.9%, n=189); group 4 - occlusion (12.7%, n=93). Endpoints were unfavorable cardiovascular events including death, myocardial infarction (MI), stroke/TIA, significant hemorrhage by BARC scale (Bleeding Academic Research Consortium).

RESULTS

In-hospital mortality and incidence of MI, stroke/TIA were similar in all groups. However, there were no cardiovascular complications in patients with critical contralateral stenosis or occlusion. Bleeding followed by redo surgery was the most frequent complication. Overall incidence of adverse cardiovascular events did not exceed 1.23%.

CONCLUSION

There was no correlation between contralateral ICA stenosis and incidence of in-hospital adverse events including death, MI, stroke/TIA. Currently, technique of CEE is well developed that is associated with low incidence of postoperative complications.

[Choice of surgical tactics in patients with acute cholecystitis complicated by cholelithiasis]

PURPOSE OF THE STUDY

Comparison of the methods of surgical treatment of cholelithiasis.

MATERIAL AND METHODS

The work is based on the experience of treating 139 patients with acute cholecystitis complicated by choledocholithiasis from 2008 to 2016, who were on treatment of the department of acute surgical diseases of the liver and pancreas, N.V. Sklifosovsky.

RESULTS

The use of percutaneous drainage of the gallbladder in an acute period can reduce complications and reduce the number of urgent video-laparoscopic cholecystectomies to 1%.

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.

[Carotid endarterectomy: three-year results of follow up within the framework of a single-centre register]

The purpose of the study was to determine the incidence rate and structure of cardiovascular complications in patients presenting with lesions of the carotid arteries and multifocal atherosclerosis, having endured carotid endarterectomy (CEA), during a three-year period within the framework of a single-centre register. The study included a total of 1,035 patients subjected to CEA over the period from 2011 to 2016. The duration of the long-term follow up averagely amounted to 42.4±18.6 months. The outcome measures assessed were as follows: death, myocardial infarction (MI), acute cerebral circulation impairment (transitory ischaemic attack) [ACCI (TIA)], clinically significant haemorrhage according to the BARC scale, unplanned repeat revascularization. In the remote period of follow up, the mortality rate did not exceed 2.3%. Of the unfavourable outcomes, most frequently observed turned out to be ACCI (TIA), with less often observed being MI. Two times a year, all patients underwent duplex scanning of the carotid arteries, whose findings revealed haemodynamically significant restenosis in 3.28% of cases. The average period of formation of restenosis amounted to 14.0±3.1 months after the operation. Three patients underwent repeat CEA and a further 16 patients endured stenting of the internal carotid artery (with 2 patients having developed intraoperative TIA). In the remote period, no cases of secondary restenosis were revealed this group of patients. It was determined that restenosis more often developed in patients having sustained classical.

[Combination therapy for benign prostatic hyperplasia in the light of clinical guidelines]

The article reviews clinical trials on the effectiveness of combination therapy with 5-reductase inhibitors and -blockers in men with benign prostatic hyperplasia (BPH). These trials have demonstrated a significant improvement in the symptoms and quality of life in this group of patients. The authors outline main strategies offered by the Russian clinical guidelines for BPH patients.

Nontrivial Recurrent Intergrowth Structure and Unusual Magnetic Behavior of Intermetallic Compound Fe32+δGe33As2

A new phase Fe_32+δGe₃₃As₂ (δ ≤ 0.136) was obtained by two-step synthesis from the elements. Fe_32+δGe₃₃As₂ crystallizes in its own structure type (space group P6/mmm, Z = 1, a = 11.919(3) Å, c = 7.558(4) Å) that can be described as a recurrent two-dimensional intergrowth of two intermetallic structure types, MgFe₆Ge₆ and Co₂Al₅. Their blocks are represented by infinite columns in the structure. No visible structural changes were observed in the temperature range from 10 to 300 K. At 125 K, Fe_32+δGe₃₃As₂ undergoes an antiferromagnetic-like transition, while above 150 K it shows a typical Curie-Weiss paramagnetic behavior. Below the transition temperature, a peculiar field-dependent magnetic susceptibility, that shows a significant increase of the susceptibility upon increasing the magnetic field, and a change in transport properties have been observed. Above 140 K, Fe_32+δGe₃₃As₂ reveals a metallic behavior, in agreement with electronic structure calculation, while below this point the resistivity nonmonotonically increases upon cooling. The Seebeck coefficient is positive, indicating that holes are the major charge carriers, and shows a broad maximum around 57 K.

New insight on bismuth cuprates with incommensurate modulated structures

The incommensurate modulated crystal structure of Bi2.27Sr1.73CuO6 + δ (2201) phase [a = 5.3874 (5), b = 5.3869 (4), c = 24.579 (3) Å; β = 90.01 (1)°, q = 0.2105 (3)a(*) + 0.538 (4)c(*), Z = 4, the (3 + 1)-dimensional monoclinic A2/a(α0γ) group] has been refined with R = 0.041, wR = 0.052 from X-ray single-crystal data including up to third-order satellite reflections. The same structure has also been considered as incommensurate composite with a2 = 2.437, b2 = 5.387, c2 = 24.614, β2 = 93.06, q2 = 0.4524a2(*)-0.243c2(*) and the (3 + 1)-dimensional A2/m(α0γ)0s group for the second component. Both approaches give quite similar results. The structure possesses oxygen disorder in the oxygen-rich region of the BiO layer. An extra O atom is determined in the bridging position shifted ∼ 0.6 Å from BiO towards the SrO layer. Its presence is the cause of the tremendous increase of the bismuth U(11) atomic displacement parameter in ∼ 20% of the unit cells (t = -0.05-0.15). Vacancies are determined in the oxygen site of the SrO layer, which may result in the oxygen content variation with annealing at different oxygen pressures. The total refined oxygen content 6.18 (1) corresponds to the results of chemical analysis.

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.

[Clinical diagnosis and prognosis of pulmonary thromboembolism]

Pulmonary thromboembolism (PTE) is a nosological entity that complicates the course of many diseases. This circumstance determines difficulties in the diagnosis and determination of further patient management tactics. Bolus-enhanced computed tomography of pulmonary arteries, a method having high resolution and high accuracy, is presently accepted to be the gold standard to verify the diagnosis. At the same time this radiocontrast study cannot be used as a screening tool by economic and other reasoning, which determines the importance of the clinical diagnosis of the disease. This review considers different approaches to diagnosing PTE and a base of elaborated clinical algorithms and comparatively assesses empirical and scoring systems for the diagnosis and prediction of a disease course characterized by the rapidness and unpredictability of an outcome even in correctly made diagnosis.

[Emergency fiberoptic bronchoscopy for diagnostics and treatment of lung atelectasis]

The article deals with results of fiberoptic bronchoscopy using during treating of patients suffering atelectasis. According to the research atelectasis is likely to advance in the first three days after serious patients have been admitted to the intensive therapy unit or after operative treatment. Left-sided atelectasis is half as widespread again the right-sided one. The research highlights the effectiveness of atelectasis X-ray diagnosis. Fiberoptic bronchoscopy in almost all the cases allowed diagnosing the degree of tracheobronchial tree obstruction and its causes. Single suction fiberoptic bronchoscopy leads to normalization and encouraged positive dynamics in 76% of all the cases (57 patients). Repeated endoscopic sanation in the first two days was necessary for 25 patients (25.3%) with unresolved or reoccurring atelectasis. The effectiveness of second research was to 84%. It's important to add that mostly patients with serious chest injury were subjected to unresolved or reoccurring atelectasis. And mainly in these cases blood was seen through the tracheobronchial tree lumen.

Crystal structure of 2-(4-methylphenyl)-2-oxo-1-(phenyliodonio)-1-(triphenylarsonio)ethanid tetrafluoroborate solved from X-ray powder data

The crystal structure of 2-(4-methylphenyl)-2-oxo-1-(phenyliodonio)-1-(triphenylarsonio)ethanid tetrafluoroborate, C33H27AsIO+BF4 –, was solved and refined from laboratory X-ray powder diffraction data in combination with a DFT calculation (CoK α1, a=24.427(2) Å, b = 13.3412(18) Å, c=22.399(2) Å, β = 119.49(2)°, S.G. C2/c, R p/R wp = 0.030/0.039). The main features of the C33H27AsIO+BF4 – structure are similar to those reported previously for arsenium and phosphorous organic compounds. The distinctive features are short I … O and I … F (2.743(19) and 2.916(17) Å, respectively) intermolecular contacts, also observed previously in the same type of compound, refined from single crystal data.

[How to validate the symptoms of pulmonary thromboembolism: how diagnostic scales help]

AIM

To detect the most important clinical symptoms suggesting pulmonary thromboembolism (PTE) and to determine the diagnostic value of the scales used to estimate the likelihood of its occurrence.

MATERIALS AND METHODS

The prospective study included 130 patients admitted to hospital with a diagnosis of PTE and a referral for a surgery clinic. Scores of the likelihood of PTE were estimated using the Canada and Geneva scales in all the patients on admission.

RESULTS

In all the patients with suspected PTE, the Canadian and revised Geneva scores averaged 4.2 +/- 0.48 and 6.21 +/- 0.5, respectively. These scores correspond to the intermediate clinical probability of PTE. In 96 patients whose diagnosis was verified by instrumental studies, the Canadian and Geneva scores were 4.41 +/- 0.57 and 6.17 +/- 0.63, respectively, which was also consistent with the intermediate clinical probability of PTE. In 34 patients, whose diagnosis of PTE was ruled out, the average scores did not virtually differ from those in the patients with the verified diagnosis and were 6.14 +/- 1.3 and 4.18 +/- 0.87, respectively. The area under characteristic curve for the Canadian scale was 0.428 and that for the Geneva scale was 0.512. With the use of a two-level interpretation system, a total of more than 6 Canadian scores and 10 Geneva scores suggested that there was a high probability of PTE.

CONCLUSION

The investigation indicated the low value of integral systems for estimating the likelihood of PTE in the total population of patients with this disease. The authors recommend the two-level interpretation system, in which a total of more than 6 Canadian scores and 10 Geneva scores were identified with a high probability (up to 80%) of PTE.

[Effectiveness of panzytrat--modern physiological enzyme preparation in complex therapy of pancreatic exocrine secretory insufficiency in cholelithiasis]

In the article the analysis of the survey with 102 patients with gallstone disease involved, 68 of whom underwent cholecystectomy and 34 were treated conservatively, is made. The content of fecal elastase 1 in stool was estimated for diagnostics of exocrine enzyme insufficiency of pancreas by immune-enzyme analysis. It was stated that 90% of patients possess secondary exocrine insufficiency of pancreas in case of gallstone disease. It is the result of complex metabolic liver abnormalities, portal and mesenterial haemodynamics, dysbiosis of large intestine which are the components of a syndrom of maldigestion and appear during gallstone disease progressing long time before hospitalization. Cholecystectomy doesn't eliminate enzyme insufficiency of pancreas. The effectiveness of using new physiological enzymatic drug Panzytrat in a complex therapy of a syndrom of maldigestion in case of gallstone disease is shown.

The high-pressure form of cadmium vanadate, CdV2O6

The crystal structure of a new high-pressure modification of cadmium divanadium hexaoxide, CdV(2)O(6), was refined from X-ray single-crystal data. It contains zigzag chains of edge-sharing VO(6) octahedra. Octahedra in adjacent chains share corners and form corrugated layers. Octahedrally coordinated Cd atoms, which lie on twofold axes, are situated between the layers. The columbite-like structure results in a strong distortion of the CdO(6) octahedra which may be stabilized only at high pressure.

[Preparation of biodegradable porous films for use as wound coverings]

We studied the preparation of polymeric films formed from solutions of poly-3-hydroxybutyrate and poly-epsilon-caprolactone in chloroform and methylene chloride. A morphological study of film chips (electron microscopy) showed that solvent evaporation results in the formation of a heterogeneous structure with interpenetrating pores (1-20 microm). We proposed a new method for introducing the proteolytic enzyme and the aminopolysaccharide chitosan into the composition of polyester films. Composite films possessed necrolytic activity and were characterized by increased hydrophilicity. Properties of enzyme-containing films from a mixture of polymers (proteolytic activity, porous structure, and increased hydrophilicity) account for their use in the preparation of biodegradable wound coverings.

[Treatment of gastroduodenal ulcer bleedings in a general hospital of emergency care]

Treatment of patients with gastroduodenal ulcer bleedings in a general hospital of emergency care is a complex of measures including of endoscopic diagnosis and stopping of bleeding, use of effective antisecretory drugs with obligatory laboratory control of acid-producing function of the stomach, surgical treatment and eradication of H. pylori. Up-to-date methods of endoscopic hemostasis - spirituous infiltration, argon-plasma coagulation, clipping of vessels in ulcer and also their combination in difficult cases - provide reliable hemostasis and allow to avoid urgent surgery. Recently we succeeded in reducing the rate of urgent surgeries performed at the height of bleedings from 70 to 40%. These methods can be recommended for clinical practice because they reduce significantly lethality rates in patients with severe conditions.

[Cell composition of bronchoalveolar lavage fluid in compound chest trauma with main damage to the lungs]

Lethal effect on alveolar macrophages is observed cytologically in all cases. Increase of neutrophils in alveols was found against the background of allergisation and inflammatory immune reactions. General state of patients with a syndrome of acute pulmonary damage but without parallel pulmonary pathology improved by day 5-20, neutrophillosis was moderate (22.8 +/- 8.3). On the contrary lavage liquid in patients with parallel pulmonary pathology had a high neutrophillosis (85.5 +/- 6.6). Endopulmonary cytogram allows prognosis and correction of treatment.

[Endoscopic intubation of the trachea in emergencies]

The article presents the results of performing endoscopic intubation of the trachea under emergency situations in patients and victims of traumatic and pyo-inflammatory alterations of organs and tissue of the neck. The technique of the trachea intubation is described. It was noted that in such patients there appear serious problems during the intubation of the trachea by the method of direct laryngoscopy which are due to considerable disturbances of the anatomo-topographic interrelations of the organs, marked edema of the tissues and by the presence of the pathological content in the lumen of the oro- and laryngopharynx. The trachea intubation performed under the control of vision with the help of a bronchofibroscope allows to avoid additional traumatization of the tissue of the oro- and laryngopharynx, to rapidly introduce the endotracheal tube into the trachea without hypoxia, to perform sanitation of the oral cavity, pharynx and the tracheobronchial tree.

[Possibility of using microbiological data in epidemiological analysis of hospital pneumonias]

A total of 528 patients with nosocomial pneumonias were examined by bacteriological methods during 4 years. The data on the patients and on 2468 bacterial strains isolated from them were computer processed using original software "Hospital Infection". Special attention was paid to hospital strains of pneumonia agents of the same taxonomic position with identical markers of antibacterial resistance. Tendencies and seasonal fluctuations in the prevalence of hospital serovars were detected. Special bacteriological studies helped detect differences in the translocation capacity of different biological variants of the agents. Routine bacteriological studies and their adequate statistical computer processing yield information needed for epidemiological analysis of the development of nosocomial pneumonias in patients of clinical wards of different profile.

[Tracheobronchoscopy in injuries of the thorax and neck]

The results of examination and treatment of patients with penetrating wounds of the thorax and the neck are analysed. Diagnostic potential abilities of roentgenography and tracheobronchoscopy are evaluated comparatively. High diagnostic and curative effectiveness of tracheobronchoscopy is detected, which is indicated in diagnosis of the wounds of the larynx and the trachea as well as in cases of technical difficulties during endotracheal intubation. Besides, tracheobronchoscopy is indicated in postoperative period for sanation of the tracheobronchial tree under visual control for prevention of broncho-pulmonary complications.

[Diagnosis and removal of foreign bodies of the trachea and bronchi]

The article presents results of examination and treatment of patients with foreign bodies in the tracheobronchial tree. It was noted that clinical manifestations were not leading in diagnosis of aspirated foreign bodies. The X-ray diagnosis is also not sufficiently effective, especially in cases with organic foreign bodies. Fiber bronchoscopy was used in 45 patients for diagnosis and removal of foreign bodies from the tracheobronchial tree. Practical recommendations are given on the method of removal of the foreign bodies depending on the shape, size and kind of the foreign body. The authors consider that the main criterion for fulfilling diagnostic fiber bronchoscopy in cases of suspected foreign body is information from the patient of probable aspiration of a foreign body. High efficiency of both diagnostic and curative fiber bronchoscopy for foreign bodies in the tracheobronchial tree is noted.

[Fiber bronchoscopy in the early diagnosis and treatment of aspiration in patients with severe craniocerebral and associated injuries]

The use of fiber bronchoscopy (FBS) for early diagnosis of aspiration in patients with grave craniocerebral (CCI) and combined injury is analyzed. Aspiration is not always associated with a clear-cut clinical picture in this cohort of patients, and x-ray examination of thoracic organs during the first hours after the injury is ineffective. High diagnostic potentials of BFS and possibility of removing the contents from the tracheobronchial tree under visual control dictate this measure for all cases with grave CCI and combined injuries during the first hours of hospitalization.

[Diagnosis and endoscopic treatment of reflux esophagitis]

The article analyses the use of endoscopic selective drug denervation of the stomach (ESDDS) in 58 patients with reflux esophagitis. Complex appraisal of the efficacy of the treatment showed the result to be good and satisfactory in one month in 96.4% of cases and 6 month after ESDDS in 89.1% of cases; the respective values in the same terms after nonoperative treatment were 66.7% and 54.5%. The pathogenetic substantiation of the use of ESDDS is the arrest of the flow of pathological vegetative impulses due to its action, which promotes restoration of regulation of the main functions of the gastroesophageal system which become almost natural, and normalizes processes of autocleansing of the esophagus. The method may be recommended for treating active manifestations of reflux esophagitis and preventing recurrences, including cases of its combination with duodenal ulcer.