High-pressure reactions between the pnictogens: the rediscovery of BiN.

We explore chemical reactions within pnictogens with an example of bismuth and nitrogen under extreme conditions. Understanding chemical reactions between Bi and N, elements representing the first and the last stable elements of the nitrogen group, and the physical properties of their compounds under ambient and high pressure is far from being complete. Here, we report the high-pressure high-temperature synthesis of orthorhombic Pbcn BiN (S.G. #60) from Bi and N2 precursors at pressures above 40 GPa. Using synchrotron single-crystal X-ray diffraction on the polycrystalline sample, we solved and refined the compound's structure and studied its behavior and compressibility on decompression to ambient pressure. We confirm the stability of Pbcn BiN to pressures as low as 12.5(4) GPa. Below that pressure value, a group-subgroup phase transformation occurs, resulting in the formation of a non-centrosymmetric BiN solid with a space group Pca21 (S.G. #29). We use ab initio calculations to characterize the polymorphs of BiN. They also provide support and explanation for our experimental observations, in particular those corresponding to peculiar Bi-N bond evolution under pressure, resulting in a change in the coordination numbers of Bi and N as a function of pressure within the explored stability field of Pbcn BiN.

[Advanced endoscopic vacuum therapy for anastomotic leakage in the upper gastrointestinal tract]. / Usovershenstvovannaya endoskopicheskaya vakuumnaya terapiya pri nesostoyatel'nosti anastomozov verkhnikh otdelov zheludochno-kishechnogo trakta.

OBJECTIVE: To evaluate the effectiveness and clinical aspects of advanced endoscopic vacuum therapy for esophagogastric, esophagointestinal and gastrointestinal anastomotic leakage, to identify disadvantages and further possibilities for its improvement. MATERIAL AND METHODS: The study included 69 people. Esophagodudodenal anastomotic leakage was detected in 34 patients (49.27%), gastroduodenal anastomotic leakage - in 30 patients (43.48%), esophagogastric anastomotic leakage - in 4 (7.25%) patients. Advanced endoscopic vacuum therapy was used for these complications. RESULTS: Vacuum therapy in patients with esophagodudodenal anastomotic leakage led to complete healing of defect in 31 (91.18%) cases. In 4 (14.8%) cases, minor bleeding was noted during replacement of vacuum dressing. There were no other complications. Three (8.82%) patients died from secondary complications. Treatment of gastroduodenal anastomotic failure resulted complete healing of defect in 24 (80%) patients. Six (20%) patients died including 4 (66.67%) cases associated with secondary complications. Vacuum therapy for esophagogastric anastomotic leakage resulted complete healing of defect in 4 (100%) patients. CONCLUSION: Advanced endoscopic vacuum therapy is a simple, effective and safe method of therapy for esophagogastric, esophagoduodenal and gastrointestinal anastomotic leakage.

Novel experimental setup for megahertz X-ray diffraction in a diamond anvil cell at the High Energy Density (HED) instrument of the European X-ray Free-Electron Laser (EuXFEL).

The high-precision X-ray diffraction setup for work with diamond anvil cells (DACs) in interaction chamber 2 (IC2) of the High Energy Density instrument of the European X-ray Free-Electron Laser is described. This includes beamline optics, sample positioning and detector systems located in the multipurpose vacuum chamber. Concepts for pump-probe X-ray diffraction experiments in the DAC are described and their implementation demonstrated during the First User Community Assisted Commissioning experiment. X-ray heating and diffraction of Bi under pressure, obtained using 20 fs X-ray pulses at 17.8 keV and 2.2 MHz repetition, is illustrated through splitting of diffraction peaks, and interpreted employing finite element modeling of the sample chamber in the DAC.

Revealing the Complex Nature of Bonding in the Binary High-Pressure Compound FeO_{2}.

Extreme pressures and temperatures are known to drastically affect the chemistry of iron oxides, resulting in numerous compounds forming homologous series nFeOmFe_{2}O_{3} and the appearance of FeO_{2}. Here, based on the results of in situ single-crystal x-ray diffraction, Mössbauer spectroscopy, x-ray absorption spectroscopy, and density-functional theory+dynamical mean-field theory calculations, we demonstrate that iron in high-pressure cubic FeO_{2} and isostructural FeO_{2}H_{0.5} is ferric (Fe^{3+}), and oxygen has a formal valence less than 2. Reduction of oxygen valence from 2, common for oxides, down to 1.5 can be explained by a formation of a localized hole at oxygen sites.

[Diagnostic and conservative treatment nuances in patients with obstructive jaundice: in the wake of Russian consensus].

The research was performed at the Loginov Moscow Clinical Scientific Center. It is based on Russian obstructive jaundice (OJ) consensus results, considered at the 45th annual Central Research Institute of Gastroenterology Scientific session Oncological issues in the gastroenterologist practice (1 March 2019). The article objective is to note the diagnostic and conservative treatment current issues in patients with OJ. The increase in the number of patients with OJ of different etiology provides problem actuality. In a large number of cases, medical treatment is delayed due to inadequate diagnostic and management, while correct patients routing today can be provided regardless of medical institution level. In this article the examination steps and conservative treatment role in patients with biliary obstruction management are presented.

[Russian consensus on current issues in the diagnosis and treatment of obstructive jaundice syndrome]. / Rossiiskii konsensus po aktual'nym voprosam diagnostiki i lecheniya sindroma mekhanicheskoi zheltukhi.

The Russian consensus document on topical issues of the diagnosis and treatment of obstructive jaundice syndrome was prepared by a group of experts in various fields of surgery, endoscopy, interventional radiology, radiological diagnosis and intensive care. The goal of this document is to clarify and consolidate the opinions of national experts on the following issues: timing of diagnosis of obstructive jaundice, features of diagnostic measures, the need and possibility of conservative measures for obstructive jaundice, and strategy of biliary decompression depending on the cause and level of biliary block.

[Outcomes of minimally invasive biliary decompression in obstructive jaundice]. / Analiz rezul'tatov miniinvazivnoi dekompressii zhelchevyvodiashchikh putei pri mekhanicheskoi zheltukhe.

AIM: To study postoperative complications and mortality after minimally invasive biliary decompression in patients with mechanical jaundice. MATERIAL AND METHODS: Prospective analysis included 2.072 patients with mechanical jaundice who underwent differential biliary decompression depending on the cause, level of obstruction, severity of jaundice and patient's condition. RESULTS: Relief of bilirubinemia and stabilization of the state were achieved in 1696 patients of the main group (98,6%) and in 328 (93.18%) patients of the control group. Mortality was similar in both groups: 8 (0.46%) and 2 (0.56%) patients. The best results were obtained in the main group for in-hospital and post-hospital complications after retrograde interventions (χ2=4.440821; df=0.891435; p<0.05) and post-hospital complications after antegrade interventions (χ2=35.52869; df= 1; p<0.05). CONCLUSION: Differentiated approach to minimally invasive biliary decompression is followed by reduced postoperative morbidity.

Metastable silica high pressure polymorphs as structural proxies of deep Earth silicate melts.

Modelling of processes involving deep Earth liquids requires information on their structures and compression mechanisms. However, knowledge of the local structures of silicates and silica (SiO2) melts at deep mantle conditions and of their densification mechanisms is still limited. Here we report the synthesis and characterization of metastable high-pressure silica phases, coesite-IV and coesite-V, using in situ single-crystal X-ray diffraction and ab initio simulations. Their crystal structures are drastically different from any previously considered models, but explain well features of pair-distribution functions of highly densified silica glass and molten basalt at high pressure. Built of four, five-, and six-coordinated silicon, coesite-IV and coesite-V contain SiO6 octahedra, which, at odds with 3rd Pauling's rule, are connected through common faces. Our results suggest that possible silicate liquids in Earth's lower mantle may have complex structures making them more compressible than previously supposed.

Fe-N system at high pressure reveals a compound featuring polymeric nitrogen chains.

Poly-nitrogen compounds have been considered as potential high energy density materials for a long time due to the large number of energetic N-N or N=N bonds. In most cases high nitrogen content and stability at ambient conditions are mutually exclusive, thereby making the synthesis of such materials challenging. One way to stabilize such compounds is the application of high pressure. Here, through a direct reaction between Fe and N2 in a laser-heated diamond anvil cell, we synthesize three ironnitrogen compounds Fe3N2, FeN2 and FeN4. Their crystal structures are revealed by single-crystal synchrotron X-ray diffraction. Fe3N2, synthesized at 50 GPa, is isostructural to chromium carbide Cr3C2. FeN2 has a marcasite structure type and features covalently bonded dinitrogen units in its crystal structure. FeN4, synthesized at 106 GPa, features polymeric nitrogen chains of [N42-]n units. Based on results of structural studies and theoretical analysis, [N42-]n units in this compound reveal catena-poly[tetraz-1-ene-1,4-diyl] anions.

[About the safety of application of nasal decongestants in the practice of pediatricians]. / O bezopasnosti primeneniia nazal'nykh dekongestantov v pediatricheskoi praktike.

Undesirable effects of the application of the intransal vasoconstricting medications are a frequent occurrence in the pediatric practice. The objective of the present study was to evaluate the role of the intranasal vasoconstricting medications in the structure of the means and methods currently available for the treatment of toxicological pathologies based at a multi-field clinical hospital. The retrospective analysis of the medical histories of the patients admitted to the toxicological department and annual reports for the period from 2015 to 2016 was undertaken. The study has demonstrated that intoxication associated with the use of the intranasal vasoconstricting medications was the most common cause of hospitalization of the children in the toxicological departments. Intoxication of this origin accounted for 15-20% of the total number of toxicological pathologies among the children. The cases of intoxication are most frequently documented in the group of children at the age between 1 and 3 years. The risk of the undesirable serious complications is especially high after the application of naphazoline-based intranasal vasoconstricting medications (71.7-77.4% of all the cases of intoxication with these products). It is concluded that the use of intranasal vasoconstricting medications in the pediatric practice should be carried out under the strict control, with the naphazoline-based preparations being totally excluded from the application.

[SELECTION OF MINI-INVASIVE PALLIATIVE DECOMPRESSION METHOD IN PATIENTS WITH MALIGNANT OBSTRUCTION OF BILIARY DUCTS BASED ON THE STUDY OF BIOCHEMICAL BILE INDEXES].

The article gives our own experience in the determination and study of additional laboratory criteria (total lipids, cholesterol, maximum and area chemiluminescence, antioxidant activity) at the local level (in bile) in patients with bile duct obstruction of malignant etiology. Constellation of metabolic disorders allowed to propose an original method for determining the lithogenicity of bile (integral indicator of lithogenicity). The obtained data made it possible to justify the need to assess the degree of metabolic disturbances in bile, on the basis of which it is possible to predict the risk of lithogenesis and the duration of stent operation, which in turn helped optimize the algorithm for choosing the method of bile ducts decompression aimed at preventing early obturation of endoprostheses.

Phase-channel dynamics reveal the role of impurities and screening in a quasi-one-dimensional charge-density wave system.

Charge density waves (CDWs), i.e. the periodic spatial modulation of coupled electronic and lattice density, are ubiquitous in low-dimensional conductors and have taken on renewed relevance due their role in state-of-the-art materials, e.g. high-T c superconductors, topological insulators and low-dimensional carbon. As CDWs are described by a complex order parameter to represent both the amplitude and phase, they are formally analogous to BCS superconductors and spin-waves, providing a prototype of collective phenomena for the further development of field theories and ab-initio calculations of complex solids. The low-energy excitations are mixed electron-phonon quanta which ideally separate into an amplitude and phase channel, and provide a sensitive probe of the ground state and non-equilibrium dynamics, including ultrafast photoinduced phase transitions. While recent studies of the amplitude modes have brought substantial progress aided by a phenomenological Ginzburg-Landau framework, we focus here on the phase modes using ultrafast terahertz spectroscopy. Experiments on K0.3MoO3 provide a more complete picture, and reveal a high sensitivity to interactions with impurities and screening effects from photogenerated carriers, both of which can be accounted for by generalizations of the model. Moreover, our considerations emphasize the need to revisit the treatment of inherent electronic damping in quantum-mechanical CDW theories.

High-pressure single-crystal synchrotron diffraction study of MnGe and related compounds.

Single crystal synchrotron diffraction for pressures up to 50 GPa has revealed an essential difference in structural properties and compressibility of MnGe compared with Mn1-x Co x Ge and Mn1-x Fe x Ge solid solutions. A negative thermal expansion has been observed for MnGe at low-temperatures and high-pressures. The single crystal refinement has shown a discontinuous change of the atomic coordinates and Mn-Ge interatomic distances of MnGe in contrast to Mn0.1Co0.9Ge. These peculiarities of MnGe are likely to be associated with high-spin-low-spin transition. The relation between anisotropy of the coordination of Mn-atom and its magnetic moment is discussed.

Structural complexity of simple Fe2O3 at high pressures and temperatures.

Although chemically very simple, Fe2O3 is known to undergo a series of enigmatic structural, electronic and magnetic transformations at high pressures and high temperatures. So far, these transformations have neither been correctly described nor understood because of the lack of structural data. Here we report a systematic investigation of the behaviour of Fe2O3 at pressures over 100 GPa and temperatures above 2,500 K employing single crystal X-ray diffraction and synchrotron Mössbauer source spectroscopy. Crystal chemical analysis of structures presented here and known Fe(II, III) oxides shows their fundamental relationships and that they can be described by the homologous series nFeO·mFe2O3. Decomposition of Fe2O3 and Fe3O4 observed at pressures above 60 GPa and temperatures of 2,000 K leads to crystallization of unusual Fe5O7 and Fe25O32 phases with release of oxygen. Our findings suggest that mixed-valence iron oxides may play a significant role in oxygen cycling between earth reservoirs.

The most incompressible metal osmium at static pressures above 750 gigapascals.

Metallic osmium (Os) is one of the most exceptional elemental materials, having, at ambient pressure, the highest known density and one of the highest cohesive energies and melting temperatures. It is also very incompressible, but its high-pressure behaviour is not well understood because it has been studied so far only at pressures below 75 gigapascals. Here we report powder X-ray diffraction measurements on Os at multi-megabar pressures using both conventional and double-stage diamond anvil cells, with accurate pressure determination ensured by first obtaining self-consistent equations of state of gold, platinum, and tungsten in static experiments up to 500 gigapascals. These measurements allow us to show that Os retains its hexagonal close-packed structure upon compression to over 770 gigapascals. But although its molar volume monotonically decreases with pressure, the unit cell parameter ratio of Os exhibits anomalies at approximately 150 gigapascals and 440 gigapascals. Dynamical mean-field theory calculations suggest that the former anomaly is a signature of the topological change of the Fermi surface for valence electrons. However, the anomaly at 440 gigapascals might be related to an electronic transition associated with pressure-induced interactions between core electrons. The ability to affect the core electrons under static high-pressure experimental conditions, even for incompressible metals such as Os, opens up opportunities to search for new states of matter under extreme compression.

[Comparative characteristics of the isotopic D/H composition and antioxidant activity of freshly squeezed juices from fruits and vegetables grown in different geographical regions].

Data presented in this paper reflect changes in antioxidant activity, the content of prooxidant factors and deuterium concentration in freshly squeezed juices from fruits and vegetables grown in different climatic regions (10 samples of juices from wholesale and retail trade network of 8 kinds of vegetables and fruits, 28 manufacturers from 14 countries). Determination of the concentration of deuterium was performed using a nuclear magnetic resonance spectrometer. Total antioxidant activity of fresh juices was determined amperometrically after dilution in 2.2 mM H3PO4 in a ratio of 1:100. Prooxidant performance was evaluated by a maximum and area of flash of chemiluminescence induced by the introduction of 0.3% hydrogen peroxide. It was found that the antioxidant activity of fresh juice from fruits and vegetables grown within the same climatic region can differ by several times. In this case, most of the fruits and vegetables of russian producers were not inferior, than antioxidant activity of the fresh juices from the same plant products grown abroad. It should be noted that the indicators of the antioxidant activity of fresh juice from Russian pears exceeded this indicator of all fresh juices from pears, imported from Argentina, South Africa and the United States of America by 21.1, 30.4 and 32.7%, respectively. In assessing the prooxidant properties of fresh juices should be noted the almost complete absence of factors with prooxidant nature only in 36% of the studied fresh juices, whose maximum performance and area of flash of chemiluminescence were less than 0.1%, including a pear and apple juices from the russian production. It should be noted that the area of chemiluminescence of the juice from potatoes, grown in Russia, was at 103.1 and 115.2% lower than in juice obtained respectively from potatoes produced in Israel and Egypt (p<0.05), indicating a higher safety of consumption of potatoes produced in Russia. When studying--the isotopic D/H composition of fresh juices it was found that the highest deuterium content was in the juice from the pears, imported from Argentina (deltaD = -72% per hundred), while the lowest concentration of deuterium was observed in the juice from the Egyptian potatoes (delta = -358% per hundred). In general, significantly lower deuterium content was determined in fresh juices made from potatoes and cabbage grown in different countries, in comparison with other fresh juices from fruits and vegetables. The smallest range of differences in the isotopic D/H was composed in freshjuices from tomato, pomegranate and oranges of Turkish manufacturers (deuterium concentration ranged in them from -221 to -214% per hundred), that can be used to confirm the geographical origin of fruits and vegetables grown in Turkey. The data reflecting the antioxidant activity, the content of prooxidant factors and deuterium concentration in the juices, allow us to recommend the latter as additional criteria when assessing the quality of food products.

[Endoscopic transpapillary lithoextraction in case of parapapillary diverticulum]. / Vozmozhnosti endoskopicheskoi chrespapillyarnoi khirurgii kholedokholitiaza pri divertikulakh papillyarnoi zony dvenadtsatiperstnoi kishki.

AIM: To present the experience of endoscopic transpapillary procedures in patients with parapapillary diverticulum. MATERIAL AND METHODS: Endoscopic transpapillary treatment of choledocholithiasis was performed in 16.8% (423) of patients with suspected bile ducts stones for the period from August 2010 to January 2015. There were parapapillary diverticulum in all cases. Patients' age was from 29 to 92 years, there were 121 men and 302 women. Endoscopic transpapillary bile drainage was made in 407 (96.3%) cases. One-stage treatment was performed in 352 (83.2%) patients. The results of endoscopic transpapillary procedures in patients with parapapillary diverticulum were analyzed. RESULTS: We revealed high efficacy of transpapillary interventions in these patients. Herewith visualization of large duodenal papilla, determination of ducts' anatomic relations with diverticular and intestinal walls and adherence to main methodical and technical aspects of procedure are very important for successful treatment.

[Experimental study of influence of lipophilic products of phytogenic origin on lipid metabolism in rats].

The article presents the results of biochemical evaluation of metabolic effects of lipophilic products of plant origin among which such oils as linseed, black nuts and walnuts oils as well as medicine «Phosphogliv¼ were selected as the most promising ones. The influence of the studied substances on lipid metabolism in experiment on male rats (170­220 g body weight) with modeled acute hepatotoxicity with carbon tetrachloride (that was achieved by subcutaneous injection of 50% oil solution of carbon tetrachloride ­ 0.5 ml/100 g of the body mass once a day during 3 days) has been investigated. Liver function was assessed by triacylglycerols content in the serum, total, esterified and nonesterified cholesterol, cholesterol in the lipoproteins of high, low and very low density, as well as by the nonesterified cholesterol and phospholipids content in the hemolysate of red blood cells. Carbon tetrachloride hepatotoxic damage was accompanied by the development of severe hypercholesterolemia associated both with the increase in total cholesterol and its content in low density lipoproteins alongside the reducing of the cholesterol concentration in high density lipoproteins, resulted in secondary dyslipoproteinemia. Inhibition of the esterification of cholesterol processes as well as the decrease in the triacylglycerols concentration was observed. It is connected with the triacylglycerols endogenous synthesis blocking in the liver, resulted from its toxic damage. It is also confirmed by cholesterol content reducing in the lipoproteins of very low density. In erythrocytes of rats with CCl4 intoxication phospholipid content decreased while the amount of nonesterified cholesterol that is a component of cell membranes, influencing the proteins and lipids diffusion, which reduces the mobility of the fatty acid residues of phospholipids, increased. The injection of the black nuts and walnuts oils as well as flax oil (intragastric injections 0.2 ml daily in the morning before the main feeding from the 7th to the 30th day of the experiment, n=25 in each group) to rats with liver failure induced by carbon tetrachloride, contributed to the partial restoration of liver tissue structure and statistically reliable decrease of lipid metabolism. Decrease in the total cholesterol content by 17.5% in the group of animals treated with linseed oil was observed; LDL cholesterol also decreased under the influence of walnuts and black nuts oils by 36.7 and 40.6% respectively. The increase in the content of phospholipids in erythrocytes of rats when administered by the studied lipophilic products has made it possible to prove the improvement of the cell membranes rheological properties. The results of the study of the influence of linseed, black nuts and walnuts oils as well as medicine «Phosphogliv¼ on animals with hepatotoxicity by CCl4 have proved positive effect of these lipophilic substances on lipid metabolism.

[EXPERIMENTAL FOUNDATION FOR LINSEED AND WALNUT OILS APPLICATION IN GASTROENTEROLOGY].

In the article the influence of the hepatotropic effect of linseed and walnut oils on the lipid composition of the rats' blood serum under CCl4 intoxication has been presented. Lipid metabolism was characterised by the assessment of total cholesterol content in the blood serum, non-etherified cholesterol, cholesterol ethers, cholesterol lipoproteids of high-, low- and very low- density as well as triaclglycerins. In rats with experimental severe liver insufficiency associated with cholesterol increase in low-density lipoproteid fraction alongside its decrease in high-density lipoproteid fraction hypercholesterolemia was progressing. Cholesterol etherification inhibition (by 31.1%) was also observed. The tendency to less intensive disorders (by 1.7-2.0) as well as the tendency to lipid metabolism normalisation in animals have been revealed under the influence of lipophilic substances studied.

[Determination of deuterium concentration in foods and influence of water with modified isotopic composition on oxidation parameters and heavy hydrogen isotopes content in experimental animals].

The article presents the results of the study of the deuterium (D) content in food products as well as the influence of deuterium depleted water (DDW) on the concentration of heavy hydrogen isotopes in the blood and lyophilized tissues of rats. The most significant difference in the content of D was found between potato and pork fat, which indexes the standard delta notation (δ) D in promille, related to the international standard SMOW (Standard Mean Ocean of Water) amounted to -83,2 per thousand and -250,7 per thousand, respectively (p<0,05). Among the investigated samples of water deuterium concentration ranged from -75,5 per thousand (Narzan) to +72,1 per thousand (Kubai), that indicates the ability of some food products to increase the concentration of heavy hydrogen atoms in the body. The data obtained in the experimental modeling of the diet of male Wistar rats in the age of 5-6 mo (weight 235 ± 16 g) using DDW (δD = -743,2 per thousand) instead of drinking water (δD = -37,0 per thousand) with identical mineral composition showed that after 2 weeks significant (p <0,05) formation of isotopic (deuterium-protium, D/H) gradient in the body is possible. Changing the direction of isotopic D/H gradient in laboratory animals in comparison with its physiological indicators (72-127 per thousand, "plasma>>tissue") is due to different rates ofisotopic exchange reactions in plasma and tissues (liver, kidney, heart), which can be explained by entering into the composition of a modified diet of organic substrates with more than DDW concentration D, which are involved in the construction of cellular structures and eventually lead to a redistribution of D and change direction of D/H gradient "plasma<