The Study of Radioactive Contaminations within the Production Processes of Metal Titanium for Low-Background Experiments.

Ultra-low-radioactivity titanium alloys are promising materials for the manufacture of low-background detectors which are being developed for experiments in astroparticle physics and neutrino astrophysics. Structural titanium is manufactured on an industrial scale from titanium sponge. The ultra-low-background titanium sponge can be produced on an industrial scale with a contamination level of less than 1 mBq/kg of uranium and thorium isotopes.

Effect of clay-zwitterionic interactions in controlling the viscoelastic properties in organomodified clays.

Investigating the rheology of 2D materials such as clays is of growing interest in various applications as it dictates their flowability and structural stability. Clay minerals present unique rheological properties, especially when in suspension. This study explores the effect of functionalizing bentonite clay with betaines of variable carbon chain lengths on the rheological properties of clay slurries to analyze their interactions in suspension.

Role of Magnesium in Ultra-Low-Radioactive Titanium Production for Future Direct Dark Matter Search Detectors.

Ultra-low-radioactive titanium is the main perspective material for cryostat fabrication in dark matter search experiments. The pathways of the uranium and thorium contamination of Ti sponges produced by the Kroll process were analyzed. The general role of Mg in Ti sponge contamination by U and Th was established.

Nanocrystals of platinum-group metals as peroxidase mimics for diagnostics.

Peroxidase mimics of nanoscale materials as alternatives to natural peroxidases have found widespread uses in biomedicine. Among various types of peroxidase mimics, platinum-group metal (PGM) nanocrystals have drawn considerable attention in recent years due to their superior properties. Particularly, PGM nanocrystals display high catalytic efficiencies, allow for facile surface modifications, and possess excellent stabilities.

Skyrmion flop transition and congregation of mutually orthogonal skyrmions in cubic helimagnets.

Magnetic chiral skyrmions are particle-like excitations with a topological charge, which are currently considered as promising objects for the next generation of magnetic memory, logic, and neuromorphic devices. In three-dimensional systems, they can form rather complex topological structures. In bulk helimagnets, elongated skyrmion tubes can be ordered either perpendicularly or parallel to an external magnetic field and such configurations coexist in a specific range of fields.

Traditional Diet and Environmental Contaminants in Coastal Chukotka III: Metals.

The article is the third in the series of four that present the results of a study on environmental contaminants in coastal Chukotka, which was conducted in the context of a multi-disciplinary investigation of indigenous foodways in the region. The article presents the results of the analysis of metals found in the samples of locally harvested terrestrial, freshwater, and marine biota collected in 2016 in coastal Chukotka. For some species of local fauna and flora, the metals content was demonstrated for the first time.

Traditional Diet and Environmental Contaminants in Coastal Chukotka II: Legacy POPs.

The article is the second in the series of four that present the results of a study on environmental contaminants in coastal Chukotka, conducted in the context of a multi-disciplinary investigation of indigenous foodways in the region. The article presents the results of the analysis of legacy Persistent Organic Pollutants (POPs) found in the samples of locally harvested food and indoor matters, collected in 2016 in coastal Chukotka. Temporal trends and circumpolar comparisons of POPs in food have been carried out.

Duplication, Collapse, and Escape of Magnetic Skyrmions Revealed Using a Systematic Saddle Point Search Method.

Various transitions that a magnetic Skyrmion can undergo are found in calculations using a method for climbing up the energy surface and converging onto first order saddle points. In addition to collapse and escape through a boundary, the method identifies a transition where the Skyrmion divides and forms two Skyrmions. The activation energy for this duplication process can be similar to that of collapse and escape.

Karyotypic Characteristics of the Ornithophilic Simulium aureum Species Group (Diptera: Simuliidae) Along the Northern Black Sea Coast and the Origin of Chromosomal Reduction.

The Simulium aureum group (Diptera: Simuliidae), also known as subgenus Eusimulium Roubaud, is a monophyletic, Holarctic taxon of bird-feeding black flies with a reduced chromosome number of two and remarkably similar external structure in all life stages. We analyzed the banding patterns of the polytene chromosomes to understand the composition of this species group along the northern coast of the Black Sea where two little-known nominal species have their type localities. Our analyses link the names Simulium krymense (Rubtsov) and Simulium maritimum (Rubtsov) with unique chromosomal characters, indicate that both are male chiasmate, and reveal the presence of Simulium angustipes Edwards along the northern coast of the Black Sea for the first time.

Classical to quantum mechanical tunneling mechanism crossover in thermal transitions between magnetic states.

Transitions between states of a magnetic system can occur by jumps over an energy barrier or by quantum mechanical tunneling through the energy barrier. The rate of such transitions is an important consideration when the stability of magnetic states is assessed for example for nanoscale candidates for data storage devices. The shift in transition mechanism from jumps to tunneling as the temperature is lowered is analyzed and a general expression derived for the crossover temperature.

Chromosomal evidence of species status and evolutionary relationships of the black fly Prosimulium petrosum (Diptera, Simuliidae) in Armenia.

The karyotype of Armenian populations of the black fly Prosimulium petrosum Rubtsov, 1955 was characterized and compared with that of all other chromosomally known Palearctic members of the Prosimulium hirtipes group. Analysis of the polytene chromosomes established that Prosimulium petrosum is most closely related to European populations of Prosimulium latimucro (Enderlein, 1925) with which it shares an identical fixed chromosomal banding sequence. Its validity as a species, separate from Prosimulium latimucro, is based on its unique sex-differential sections in the expanded centromere region of chromosome I, in agreement with the unique structural configuration of the hypostomal teeth of its larvae.

[Identification of potentially invasive species of black flies [Diptera: Simuliidae] from Armenia based on an analysis of variability in the mtDNA barcode of the cox1 gene and chromosomal polymorphism].

Black flies (Diptera, Simuliidae) are well known for their medical, environmental, and veterinary importance. The simuliid fauna of Armenia includes 53 species. A number of dominant species are of ecological importance.

[The comparative analysis of the surgical treatment of the familial adenomatosis of the colon with the use of cell transplantation].

Authors represent the surgical technique of colectomy with preserving the natural intestinal passage in the treatment of the familial colic adenomatosis. The technique is based on the preserving the distal part of the rectum with its demucosation and connecting with the ileal conduit. The rectal mucosa reconstruction is performed with the use of allogenic transplantation of fetal intestinal cells.

Visual outcomes after carotid reconstructive surgery for ocular ischemia.

Aims: This study aimed to determine the influence of carotid artery surgery on ocular functions and ocular blood flow in patients with ocular ischaemic syndrome (OIS) in the late postoperative period.

Methods: One hundred and eighty patients with OIS were operated on; 104 of them suffered from acute forms of the ischaemic disease and 76 patients had chronic forms of ocular ischaemia. Before surgery and in the course of 6 months and 12 months afterwards, all the patients were examined.

[Current approach for hypertension retinopathy screening and diagnosis].

Literature review is devoted to early diagnosis and screening of hypertension retinopathy (HR). The data of large epidemiological trials are presented, they prove an association of HR with stroke, coronary heart disease, risk stratification of these conditions is estimated, besides effect of blood pressure level on HR signs onset is studied. Pathophysiology of main clinical stages of retina impairment in arterial hypertension is discussed.

[A case of vasoocclusive retinal damage in moya-moya disease].

Retinal vessel occlusion and eye haemodynamics damage is described in moya-moya disease, a rare occlusive cerebrovascular condition characterized by progressing stenosis and occlusion of cerebral arteries with collateral development in basal vascular system. Data concerning neuroophthalmological features, diagnostic and treatment methods are presented. Necessity of MR-tomography and MR-angiography in ischemic retinal damage is emphasized.

[Changes in the organ of vision in pathological tortuosity and atherosclerotic stenosis of the carotid arteries].

Pathological tortuosity of the carotid arteries is a cause of not only cerebral circulatory disorders, but also visual impairments. There are nonspecific and specific signs of circulatory disorders in the anterior ocular segment - bulbar conjunctiva. In pathological tortuosity of the carotid arteries visual impairments are divided into transient, acute, and chronic.

[Mutation analysis of K-ras protooncogene in colorectal adenocarcinomas and polyps in Russian patients].

To estimate diagnostic value of K-ras mutations during cancer risk group formation, they were studied in the samples of sporadic carcinomas (n = 33) and malignant (n = 13) polyps of large intestine obtained during surgery or polypectomy. Using PCR analysis, restriction analysis, SSCP analysis and automated sequencing, eight various point mutations were revealed. Six of them were located in codon 12 and two, in codon 13 of the K-ras gene.

[Pathological kinking of carotid arteries as a risk factor for age-related macular degeneration].

The present work was aimed at studying clinical symptoms and the incidence rate of age-related macular degeneration (ARMD) in patients diagnosed with pathological kinking of carotid arteries. A total of 63 patients presenting with pathological kinking of carotid arteries were examined. Of these, 58 were found to have age-related macular degeneration manifesting itself by degenerative alterations in the retinal pigment epithelium (RPE) in 14 (24.

Combining data sets of organochlorines (OCs) in human plasma for the Russian Arctic.

As part of AMAP's human circumpolar study of POPs, an international effort was initiated to extend coverage to communities across the Russian Arctic. Two additional laboratories were invited to join the analytical component of this effort, resulting in four participating analytical centres. Although quality assurance measures were put in place, and the level of performance of the laboratories was generally acceptable, deficiencies in the analytical protocols used were recognized subsequent to the collection and analyses of the plasma specimens.

Solution-phase synthesis of a combinatorial library of 3-[4-(coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acid amides.

The parallel solution-phase synthesis of a new combinatorial library of 3-[4-(R1-coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acid amides 9 has been developed. The synthesis involves two steps: 1) the synthesis of core building blocks - 3- [4-(coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acids, 6 - by the reaction of 3-(omega-bromacetyl)coumarins 1 with 3-amino(thioxo)methylcarbamoylpropanoic acid (5); 2) the synthesis of the corresponding 3-[4-(coumarin-3-yl)-1,3-thiazol-2-yl- carbamoyl]propanoic acids amides 9 using 1,1'-carbonyldimidazole as a coupling reagent. The advantages of the method compared to existing ones are discussed.

Blood concentrations of persistent toxic substances in the indigenous communities of the Russian Arctic.

Objectives: Investigation was carried out within the framework of the large-scale international project "Persistent Toxic Substances (PTS), Food Security and Indigenous People of the Russian North" under RAIPON/AMAP/GEF aegis. Objectives of the project are to obtain comprehensive information on exposure of indigenous populations to contaminants through food chains (and other sources), and to investigate the possible health effects connected to this exposure. Four regions of Russia are involved in the project: Kola Peninsula (Murmansk oblast), Nenetsk okrug (Pechora river basin), Taimyr Peninsula, Chukotka Peninsula.

Snow and ice concentrations of selected persistent pollutants in the Ob-Yenisey river watershed.

As one of the largest river systems attached to the Arctic Basin, the Ob-Yenisey watershed has the potential to be a major supply route of persistent organic pollutants into marine ecosystems of the Arctic Ocean. Snowfall and ice formation taking place in the Ob-Yenisey river basin and shelf are key components of the system of processes responsible for the transfer of pollutants from this high latitude river to the adjacent Kara and Barents Seas. Here we examine a large data set on persistent organic pollutants in snow and ice determined for areas within the Ob (interior and coastal), Yenisey and adjacent shelf.

[Calcium channel blockers in the treatment of primary open-angle glaucoma].

Study of nifedipine effect on the hemodynamics in the orbital and central retinal arteries showed that nifedipine therapy in a dose of 10 mg 3 times a day for 1 month results in decrease of resistance of the orbital and central retinal arteries in patients with stage I primary open-angle glaucoma. No changes in the visual field, arterial pressure, or hydrodynamics were noted.

[The cardiovascular reactions during audiogenic seizures in rats genetically predisposed to epilepsy].

Changes in arterial pressure (AP) and venous tone were studied in Krushinskiĭ-Molodkina (KM) rats genetically predisposed to audiogenic seizure, during the audio stress and 20 min after it. The venous tone was estimated by the mean circulatory filling pressure (MCFP) during a short arrest of circulation by inflating a balloon in the right atrium. It was shown that, during seizure, AP raised from 104 to 156 mm Hg on the average, while MCFP decreased from 8.