High-pressure transformation of dithiazolylidene-dithiazolium polyiodide with N-H…N hydrogen bond: A Raman Spectroscopy study

The insight into the behavior of polyiodides under non-ambient conditions can enrich the practical applications due to obtaining materials with adjustable and tunable conducting properties. In this work Raman spectroscopy study in the range 0 - 6.5 GPa has been performed for dithiazolylidene-dithiazolium zigzag polyiodide with N-H…N hydrogen bond. Variations of band positions in the low-wavenumber region of Raman spectra have been attributed to the changes in the anionic part of the unit cell. The association of different interacting polyiodide subunits at pressure above 1.5 GPa leads to the emergence of the bands at 98 and 115 cm^-1 due to consistent vibrations in the I₈^2- zigzag. The emergence of the band at 159 cm^-1 above 0.28 GPa can be assigned to N-H…N hydrogen bond vibration. The obtained results depict undergoing structure transformations: the stronger are cation…cation and anion…anion interactions the more likely is the observation of conducting properties due to the formation of polyiodide zigzag and strongly-bound hydrogen-bonded fragment.

Spectroscopy of structurally disordered hydrated iron fluoridotitanate in the regions of vibrational and electronic excitations

Raman and optical absorption spectra of disordered hydrated iron fluoridotitanate (HITF) single crystal were studied. Temperature transformations of the Raman spectra indicate independent ordering processes of the [TiF₆]^2- and [Fe(H₂O)₆]²⁺ complexes below the structural phase transition. The absorption spectrum in the near-infrared and visible ranges includes transitions from the high spin ground state ⁵T₂ of Fe²⁺ ion to the excited ⁵E state and a set of excited triplets. Analysis by Tanabe-Sugano method gives crystal field Dq = 490 cm^-1 and Racah parameters B = 340 cm^-1 and C = 1904 cm^-1. Considerable decrease of B parameter as compared to the free ion value indicates a decrease of interelectron repulsion in the disordered neighborhood of Fe²⁺ ions.

[Methodical approaches to annotation and labeling of histological images in order to automatically detect the layers of the stomach wall and the depth of invasion of gastric cancer]

OBJECTIVE

Development of original methodological approaches to annotation and labeling of histological images in relation to the problem of automatic segmentation of the layers of the stomach wall.

MATERIAL AND METHODS

Three image collections were used in the study: NCT-CRC-HE-100K, CRC-VAL-HE-7K, and part of the PATH-DT-MSU collection. The used part of the original PATH-DT-MSU collection contains 20 histological images obtained using a high performance digital scanning microscope.

Each image is a fragment of the stomach wall, cut from the surgical material of gastric cancer and stained with hematoxylin and eosin. Images were obtained using a scanning microscope Leica Aperio AT2 (Leica Microsystems Inc., Germany), annotations were made using Aperio ImageScope 12.3.3 (Leica Microsystems Inc., Germany).

RESULTS

A labeling system is proposed that includes 5 classes (tissue types): areas of gastric adenocarcinoma (TUM), unchanged areas of the lamina propria (LP), unchanged areas of the muscular lamina of the mucosa (MM), a class of underlying tissues (AT), including areas of the submucosa, own muscular layer of the stomach and subserous sections, image background (BG). The advantage of this marking technique is to ensure high efficiency of recognition of the muscularis lamina (MM) - a natural «line» separating the lamina propria of the mucous membrane and all other underlying layers of the stomach wall. The disadvantages of the technique include a small number of classes, which leads to insufficient detailing of automatic segmentation.

CONCLUSION

In the course of the study, an original technique for labeling and annotating images was developed, including 5 classes (types of tissues). This technique is effective at the initial stages of teaching mathematical algorithms for the classification and segmentation of histological images. Further stages in the development of a real diagnostic algorithm to automatically determine the depth of invasion of gastric cancer require the correction and development of the presented method of marking and annotation.

[Severe spine lesion following alkaptonuria. Case report]

Alkaptonuria is a rare autosomal recessive disease. In these patients, melanin-like compounds as the final products of impaired metabolism of homogentisic acid are deposited mainly in connective tissue, including cartilage tissue of intervertebral discs. Similar to other degenerative spine diseases, lumbar segment is often damaged. The authors report a 67-year-old patient with alkaptonuria. Compression of cauda equina by damaged cartilage masses of intervertebral discs and spine ligaments with deposits of ochronotic pigment is described. Previously diagnosed alkaptonuria in this patient was confirmed by surgical findings (black pigmentation) and histological data.

Synthesis of Samarium OxysulfateSm2O2SO4 in the High-Temperature Oxidation Reaction and Its Structural, Thermal and Luminescent Properties

The oxidation process of samariumoxysulfide was studied in the temperature range of 500–1000 °C. Our DTA investigation allowed for establishing the main thermodynamic (∆Hº_exp = −654.6 kJ/mol) and kinetic characteristics of the process (E_a = 244 kJ/mol, A = 2 × 10¹⁰). The enthalpy value of samarium oxysulfate (ΔHºf (Sm₂O₂SO_4(monocl)) = −2294.0 kJ/mol) formation was calculated. The calculated process enthalpy value coincides with the value determined in the experiment. It was established that samarium oxysulfate crystallizes in the monoclinic symmetry class and its crystal structure belongs to space group C2/c with unit cell parameters a = 13.7442 (2), b = 4.20178 (4) and c = 8.16711 (8)Å, β = 107.224 (1)°, V = 450.498 (9)ų, Z = 4. The main elements of the crystalline structure are obtained and the cation coordination environment is analyzed in detail. Vibrational spectroscopy methods confirmed the structural model adequacy. The Sm₂O₂SO₄luminescence spectra exhibit three main bands easily assignable to the transitions from ⁴G_5/2 state to ⁶H_5/2, ⁶H_7/2, and ⁶H_9/2 multiplets.

Structural, electronic and vibrational properties of LaF3 according to density functional theory and Raman spectroscopy

Crystal structure of LaF₃ single crystal is refined in tysonite-type trigonal unit cell P [Formula: see text] c1 using density functional theory calculations and Raman spectroscopy. It is shown that trigonal structure with P [Formula: see text] c1 space group is more energy-efficient than hexagonal structure with space group P6₃ cm. Simulated Raman spectra obtained using LDA approximation is in much better agreement with experimental data than that obtained with PBE and PBEsol functionals of GGA. The calculated frequency value of silent mode B ₂ in case of hexagonal structure P6₃ cm was found to be imaginary (unstable mode), thus the energy surface obtains negative curvature with respect to the corresponding normal coordinates of the mode which leads to instability of the hexagonal structure in harmonic approximation. The A _1g line at 214 cm^-1 in Raman spectra of LaF₃ related to the translation of F2 ions along c axis can be connected with F2 ionic conductivity.

[Phenomenological Regularities of Assessment of Left Ventricle Function in Mitral Valve Insufficiency]

OBJECTIVE

to examine relationship between anatomical changes of the left ventricle (LV), dynamics of velocity of its volume modification, and blood flows in the LV in patients with mitral regurgitation (MR) before and after surgical treatment.

MATERIALS AND METHODS

We included into this study 58 patients with severe 3-4 degree MR (38 men, 20 women aged 24-69 [mean age 51±9] years) in sinus rhythm (96 %) or atrial fibrillation (4 %). The control group included 86 healthy volunteers, mean age 39±7 years. Transthoracic echocardiographic studies were performed in both groups by standard technique at rest using a high-quality echocardiograph Vivid E9, equipped with a 3.5-4.6 MHz multi frequency transducer (in patients before and after surgical repair - mitral valve [MV] replacement and MV reconstruction with annuloplasty ring). The analysis of files recorded was performed off-line by vector analysis technique including estimation of myocardial deformation velocities and dynamics of LV volume modification, construction of "flow-volume" diagram, calculation of the expended kinetic energy, and registration of intraventricular blood flows.

RESULTS

End diastolic volume (EDV), end systolic volume (ESV) and total stroke volume (TSV) (effective + retrograde) were significantly increased in patients with severe LV volume overload before surgery in comparison with the control group (p.

Nature of phase transitions in ammonium oxofluorovanadates, a vibrational spectroscopy study of (NH4)3VO2F4 and (NH4)3VOF5

Two ammonium oxofluorovanadates, (NH₄)₃VO₂F₄ and (NH₄)₃VOF₅, have been investigated by temperature-dependent infrared and Raman spectroscopy methods to determine the nature of phase transitions (PT) in these compounds. Dynamics of quasioctahedral groups was simulated within the framework of semi-empirical approach, which justified the cis-conformation of VO₂F₄^3- (C_2v) and the C_4v geometry of VOF₅^3-. The observed infrared and Raman spectra of both compounds at room temperature (RT) revealed the presence at least of two crystallographically independent octahedral groups. The first order PT at elevated temperatures is connected with a complete dynamic disordering of these groups with only single octahedral state. At lower temperatures, the octahedra are ordered and several octahedral states appear. This PT is the most pronounced in the case of (NH₄)₃VOF₅, when at least seven independent VOF₅^3- octahedra are present in the structure below 50K, in accordance with the Raman spectra. Ammonium groups do not take part in PTs at higher and room temperatures but their reorientational motion freezes at lower temperatures.

[SPECT/CT radiation in treatment of bone metastases of osteosarcoma]

The aim of this study was to demonstrate the diagnostic ca- pabilities to control effects of radiotherapy treatment in patient with osteosarcoma bone metastases by SPECT-CT method. There was conducted SPECT/CT treatment monitoring of the patient with bone metastases of osteosarcoma after external radiotherapy and cyber knife. There were detected changes in the SPECT/CT-pictures of treated bones osteosarcoma metasta- ses. The SPECT/CT has proven as a reliable method of dynam- ic control at radiotherapy. Treatment effect all of these methods was to reduce or to get absent accumulation of bone-tropic radiopharmaceutical labeled with 99mTc-technetium. SPECT/ CT study was a demonstrative method for early determination of pathological metabolism degree in bone metastases of os- teosarcoma. SPECT/CT was an effective method of treatment monitoring of bone metastases after radiotherapy.

[PREDICTORS OF RISK OF SURGERIES IN PATIENTS WITH FAILURE OF THE CORONARY CIRCULATION]

The paper analyzes the study of the myocardium in patients with coronary artery disease to identify new predictors of reduction of myocardial contractility. Research carried out on the basis of transthoracic echocardiography and transesophageal on Vivid 7 unit and Vivid-E9 with multifrequency array sensor (3.5-5.5 MHz) by method with the obligatory registration ofstandard ECG. All studies in the form of static and moving images (3-5 cardiocycles Cine-loop) is stored in workstation memory Echopac 7 (GE Vingmed Ultrasound, USA). To assess the functional state of left ventricular myocardium was measured geometry of the cavities of the heart and determines the main central hemodynamics: end-diastolic and end-systolic volume qf the left ventricle, the si:e of the left atrium, the rate of displacement of the myocardium ofivector analysis, stroke vohne, duration of the phases ofthe cardiac cycle, the pressure in the pulmonary circulation. In patients with low reserves, changes are observed during the period of contraction and relaxation. The maximum rate peaks do not coincide, and are significantly reduced compared with the outcome. Acceleration, velocity of bloodflow in the left ventricular cavity shows changing the direction of blood flow--this is nothing other than the power characteristic, which reflects energy during the contraction. Determination of the eddy currents and the velocity characterizes the acceleration of change in the direction of blood flow

Electronic structure of β-RbSm(MoO4)2 and chemical bonding in molybdates

Microcrystals of orthorhombic rubidium samarium molybdate, β-RbSm(MoO₄)₂, have been fabricated by solid state synthesis at T = 450 °C, 70 h, and at T = 600 °C, 150 h.

[The formation of liquid-crystalline dispersions of DNA-chitosan complexes under the conditions of molecular crowding]

The formation of liquid-crystalline dispersions from DNA-chitosan complexes in polyethyleneglycol-containing solutions was studied. It was shown that the molecular crowding affects neither the efficiency of binding of chitosan molecules to DNA nor the mode of spatial packing of DNA-chitosan complexes in particles of liquid-crystalline dispersions.

Analysis of binding specificity of disulfide bonded dimeric lambda-Cro V55C protein with generic hexamer oligonucleotide microchip

Binding specificity of mutant V55C disulfide bonded dimeric lambda-Cro protein (CroVC) to double-stranded DNA (dsDNA) was studied using generic hexamer oligonucleotide microchip. The curves of dissociation of hybridized DNA in the presence and absence of CroVC were converted into the effective discriminant constants to assess the relevant thermodynamic equilibrium binding constants for dsDNA-protein complexes. Then, tiling of longer oligonucleotides with shorter oligomers was used to search for sequence motifs with the highest binding specificity similarly to sequencing by hybridization. The comparison of the deduced sequences with the known natural operator half-sites demonstrated the principal ability to discern and reconstruct the major parts of 7-mer motifs corresponding to the strongest binding of CroVC subunits. Our results show the applicability of generic microchips to the analysis of binding specificity in the case of multi-subunit DNA-binding proteins.

[Dye with low specificity to nucleotide sequences of DNA: use for assessing the quantity of oligonucleotides, immobilized in cells of biological microchips]

To assess the DNA amount in samples (e.g., in biological microchip gel pads) by means of fluorescent dyes, one should use the dyes whose fluorescence weakly depends on DNA composition and structure. With the ImD-310 dye created for this purpose, we have analyzed the staining of single- and double-stranded oligo- and polynucleotides of different nucleotide composition, length, and concentration both in solution and being immobilized in biological microchip gel pads. It turned out that ImD-310 has no pronounced specificity to the single- and double-stranded nucleotide sequences, while the intensity of fluorescence for the dye complexes with d(A)8, d(T)8, d(C)8, and d(G)8 at high temperatures (50 degrees C) differs by less than 25%. A linear correlation has been established between the intensity of fluorescence and the amount of oligonucleotides immobilized on a biological microchip. The plots of the intensity of fluorescence against the concentration of NaCl and the temperature were obtained. By using a generic microchip containing all 4096 hexamer oligonucleotides, it has been determined that the dye has no distinct specificity to any certain motifs of the nucleotide sequence. Thus, ImD-310 may serve as an efficient fluorescent probe to quickly estimate the amount of oligonucleotides immobilized in a microchip, in an electrophoretic gel, etc.