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Y2O3 transparent ceramics with different amounts of ZrO2 were obtained by reactive vacuum sintering at a relatively low temperature of 1735 °C for 22 h. The influence of ZrO2 concentration within the 0–15 mol.% range on the microstructure, phase composition, microhardness, and optical properties of ceramics in the visible and IR ranges was investigated. SEM and XRD results indicate the absence of secondary phases in the studied concentration range, indicating the formation of single-phase solid solutions. It was shown that doping by ZrO2 considerably decreases the average grain size of ceramics, while microhardness has the opposite behaviour. 15 mol.% ZrO2-doped Y2O3 ceramics demonstrated the highest transmittance in the visible wavelength range. On the other hand, 5 and 7 mol.% ZrO2-doped Y2O3 could be considered promising materials for the first atmospheric window (3–5 μm).

A map of debris flow activity of the Geysernaya river basin, where large-scale debris flow processes associated with the collapse of fragments of the left side of the valley have been observed three times over the past 40 years, was compiled. Three independent debris flow areas of the river basin have been identified and characterized: the upper reaches of the river — the Levaya Geysernaya basin, the middle river course — below the dammed lake formed in 2014, and the lower downstream part — below the dammed lake that existed in 2007–2014. It was found that debris flow processes are typical for most of the Geysernaya river tributaries. Moreover, in the left tributaries debris flows may have aseasonal character, because they are formed in conditions of constant heating and active gas-hydrothermal influence within the thermal fields. The landslide dam formed in 2014 is resistant to erosion, and an independent breakthrough of the dammed lake is unlikely. With further erosion of the 2007 dam and the expansion of the breach in the dam body, collapse of its sides and debris flow in the lower part of the Geysernaya river valley cannot be ruled out. Risks of rockfall, landslide and debris flow processes, the initiation of which is most likely on the left side of the valley, should be considered in planning the development of recreational facilities.

Background: Intraductal papillary mucinous neoplasms (IPMNs) have the potential to evolve into pancreatic adenocarcinoma (PDAC). While main-duct IPMNs (MD-IPMNs), involving the main pancreatic duct (MPD), are less common than side-branch IPMNs (SB-IPMNs) or mixed-type IPMNs (mixed-IPMNs), their malignant transformation potential is far greater. Controversy exists between different guidelines in terms of recommended management strategies. This study was aimed at assessing the utility of the radiological follow up of MD-IPMNs and mixed-type IPMNs, including prevalence of worrisome radiological findings as well as clinical and laboratory parameters, and their correlation with the development of progression or pancreatic adenocarcinoma. Methods: Eighty-four patients with MD-IPMNs or mixed-type IPMNs who underwent at least one magnetic resonance cholangiopancreatography (MRCP) were included. Clinical and laboratory data were obtained retrospectively. A cross-sectional analysis was carried out to establish clinical and laboratory parameters associated with development of PDAC. A retrospective cohort analysis was performed on 44 patients who had at least six months of follow up, trying to identify factors correlating with worrisome radiological features. Results: Nine cases (10.7%) of PDAC were recorded in this cohort. The laboratory and imaging factors associated with cyst size progression greater than 5 mm during follow up were elevated alanine transaminase (ALT) levels, the maximal cyst size, and the MPD diameter. Cross-sectional analysis indicated that PDAC was associated with nausea (p = 0.01), as well as increased levels of aspartate aminotransferase (AST) (p = 0.05), gamma glutamyl transpeptidase (GGT) (p = 0.01), and alkaline phosphatase (ALP) (p = 0.01). Conclusions: Elevated levels of liver enzymes were associated with IPMN progression and, subsequently, the development of PDAC. ALT levels, maximal cyst size, and MPD diameter are associated with the progression of cyst size. These data may aid in risk-stratifying patients when determining the follow up approach for IPMNs.

The detachment of large parts of low-angle mountain glaciers resulting in massive ice–rock avalanches have so far been believed to be a unique type of event, made known to the global scientific community first for the 2002 Kolka Glacier detachment, Caucasus Mountains, and then for the 2016 collapses of two glaciers in the Aru range, Tibet. Since 2016, several so-far unrecognized low-angle glacier detachments have been recognized and described, and new ones have occurred. In the current contribution, we compile, compare, and discuss 20 actual or suspected large-volume detachments of low-angle mountain glaciers at 10 different sites in the Caucasus, the Pamirs, Tibet, Altai, the North American Cordillera, and the Southern Andes. Many of the detachments reached volumes in the order of 10–100 million m3. The similarities and differences between the presented cases indicate that glacier detachments often involve a coincidental combination of factors related to the lowering of basal friction, high or increasing driving stresses, concentration of shear stress, or low resistance to exceed stability thresholds. Particularly soft glacier beds seem to be a common condition among the observed events as they offer smooth contact areas between the glacier and the underlying substrate and are prone to till-strength weakening and eventually basal failure under high pore-water pressure. Partially or fully thawed glacier bed conditions and the presence of liquid water could thus play an important role in the detachments. Surface slopes of the detached glaciers range between around 10∘ and 20∘. This may be low enough to enable the development of thick and thus large-volume glaciers while also being steep enough to allow critical driving stresses to build up. We construct a simple slab model to estimate ranges of glacier slope and width above which a glacier may be able to detach when extensively losing basal resistance. From this model we estimate that all the detachments described in this study occurred due to a basal shear stress reduction of more than 50 %. Most of the ice–rock avalanches resulting from the detachments in this study have a particularly low angle of reach, down to around 5∘, likely due to their high ice content and connected liquefaction potential, the availability of soft basal slurries, and large amounts of basal water, as well as the smooth topographic setting typical for glacial valleys. Low-angle glacier detachments combine elements and likely also physical processes of glacier surges and ice break-offs from steep glaciers. The surge-like temporal evolution ahead of several detachments and their geographic proximity to other surge-type glaciers indicate the glacier detachments investigated can be interpreted as endmembers of the continuum of surge-like glacier instabilities. Though rare, glacier detachments appear to be more frequent than commonly thought and disclose, despite local differences in conditions and precursory evolutions, the fundamental and critical potential of low-angle soft glacier beds to fail catastrophically.

We analyzed multi-time satellite images of the Central Caucasus glacial zone and interpreted more than thirty rock avalanche events in the 21st century with a total damage area of more than 25 km2 (including the collapse zone of the Kolka Glacier disaster). The highest rock and rock-ice avalanche activity is detected in the section of The Greater Caucasus range (northern and southern slopes) with a length of about 20 km between the Bashkara and Kulaktau peaks (16 rock avalanches) and in the section of the Kazbek-Dzhimaray Massif (series of rock avalanches to the surface of Kolka, Suatisi and Devdoraki glaciers). The feature of the rock and ice-rock avalanches is the large runout distance. For 12 events (about 40%) the distance was more than 2000 m. One ice-rock avalanche from the Mount Kazbek (excluding the Kolka Glacier disaster in 2002) reached the runout distance more than 10 km. In some areas, the rock avalanches occurred several times. In particular, a large number of avalanches were in the cirque of the Kolka Glacier; the last of them at the end of 2019. Thrice шт each case, rock avalanches originated from Mount Bashkara, in the cirques of the Murkvam Glacier, the East Shtulu Glacier, and the Devdoraki Glacier. Ice and rock avalanches were the initial stage of the complex process of the Kolka Glacier disaster and following catastrophic glacial debris flow in the Genaldon/Gizeldon River valley in 2002. Also, they were causes of glacier surges, formation of dammed lakes, and debris flows. As a result of the collapse of the hanging glacier and bedrock, the former right tributary of the Kolka Glacier surged to 200 m in 2006. Ice-rock avalanche from Mount Kazbek in 2014 load up the former right tributary of the Devdoraki Glacier and caused its advancing in 2015–2019, at a distance of more than 400 m. The avalanches caused catastrophic debris flows in the Amilishka/Kabakhi River valley in 2014, the Mestiachala River valley in 2019. Rock avalanches can cause outbursts of lakes and debris flows. Two dammed lakes formed as a result of the rock avalanche from the cirque above the Seri Glacier in the Tviberi River valley of the in May 2016. The lakes (total area was more than 0.05 km2) have outburst at the end of August 2017 after heavy rains. Rock avalanches of the 20th century led to an abrupt deceleration in the retreat of the Yusengi, Bartuytsete, East Shtulu and Mosota glaciers. The formation of rock avalanches in the 21st century took place at high altitudes (an average of about 3900 m). Possibly, the reason was associated with an increase of the «0» isotherm and of the high border of the zone of intense frost weathering due to climate warming. Some rock avalanches in the section of the Kazbek-Dzhimarai Massif have been caused by endogenous factors (seismicity and volcanism).

The paper presents the reconstruction of the most catastrophic debris flows in the Gerkhozhan-Su river valley (North Caucasus, Russia) based on a chain of mathematical models. Transport-shift model was applied for 6 sections of debris flow formation or intense material increment, while for the rest the FLO-2D hydrodynamic model was used. A number of numerical experiments were carried out in the transport-shift model for a section of a debris flow origination site with a change in the parameters of a potential debris flow-forming soils, such as initial moisture content and density. According to the simulation results, with a rise in moisture content, the maximum debris flow discharge can increase by about 2.8 times. Modeling of debris flow in the Gerkhozhan-Su river valley was conducted for the case of low density debris flow. Based on the results, debris flow wave hydrographs were obtained at 12 sections. The results of modeling are in general agreement with the commonly accepted reconstructed pattern of the debris flow in 2000 and values obtained by videomaterials.

Background: Intraductal papillary mucinous neoplasms (IPMNs) have the potential to evolve into pancreatic adenocarcinoma (PDAC). While main-duct IPMNs (MD-IPMNs), involving the main pancreatic duct (MPD), are less common than side-branch IPMNs (SB-IPMNs) or mixed-type IPMNs (mixed-IPMNs), their malignant transformation potential is far greater. Controversy exists between different guidelines in terms of recommended management strategies. This study was aimed at assessing the utility of the radiological follow up of MD-IPMNs and mixed-type IPMNs, including prevalence of worrisome radiological findings as well as clinical and laboratory parameters, and their correlation with the development of progression or pancreatic adenocarcinoma. Methods: Eighty-four patients with MD-IPMNs or mixed-type IPMNs who underwent at least one magnetic resonance cholangiopancreatography (MRCP) were included. Clinical and laboratory data were obtained retrospectively. A cross-sectional analysis was carried out to establish clinical and laboratory parameters associated with development of PDAC. A retrospective cohort analysis was performed on 44 patients who had at least six months of follow up, trying to identify factors correlating with worrisome radiological features. Results: Nine cases (10.7%) of PDAC were recorded in this cohort. The laboratory and imaging factors associated with cyst size progression greater than 5 mm during follow up were elevated alanine transaminase (ALT) levels, the maximal cyst size, and the MPD diameter. Cross-sectional analysis indicated that PDAC was associated with nausea (p = 0.01), as well as increased levels of aspartate aminotransferase (AST) (p = 0.05), gamma glutamyl transpeptidase (GGT) (p = 0.01), and alkaline phosphatase (ALP) (p = 0.01). Conclusions: Elevated levels of liver enzymes were associated with IPMN progression and, subsequently, the development of PDAC. ALT levels, maximal cyst size, and MPD diameter are associated with the progression of cyst size. These data may aid in risk-stratifying patients when determining the follow up approach for IPMNs. [ABSTRACT FROM AUTHOR]

Aim. To study the effects of fixed-dose indapamide/perindopril combination on endothelial function and arterial stiffness in patients with uncontrolled stage 1-2 hypertension (HTN) and chronic kidney disease (CKD).Material and methods. Total of 100 patients with uncured or uncontrolled with ≥3 months antihypertensive therapy HTN and CKD G3 (67% females, mean age 59,1±12,5 years) were included in the study. Each patient took indapamide/perindop combination in accordance with 1 of 3 existing regimes (depending on doses) for 3 months. Primary aim was to assess the effects of indapamide/perindopril combination on endothelial function and parameters of arterial stiffness after 12 weeks of treatment (assessment by AngioScan diagnostic complex). Secondary aims were achievement of target blood pressure (BP) after 4 and 12 weeks of therapy and assessment of glomerular filtration rate (GFR) and the albumin-tocreatinine ratio (ACR) changes after 12 weeks.Results. Initially, there was an increase in arterial stiffness parameters in all patients, and during treatment decrease was observed: central systolic BP (SBP) from 120±10,1 to 112,9±6,3 mm Hg, median augmentation index from 10,9% to 4,6%, stiffness index from 8,1±2,4 to 7,1±0,9, vascular age decreased by 9,6% (р< 0,001 for trend). Significant improvement of endothelial function was observed regardless of diabetes presence: occlusion index increased from 1,5±0,3 to 1,7±0,5, median phase shift — from -4,6 to -2,4 ms (p< 0,01). After 4 weeks, 27% of patients reached target BP, by the end of the study — 90%. A decrease in the median ACR from 16,3 to 15,0 mg/g, GFR increase from 50,2±7,6 to 53,6±8,7 ml/min/1,73 m2 were observed (p< 0,01 for trend).Conclusion. Therapy with a fixed-dose indapamide/perindopril combination in patients with uncontrolled stage 1-2 HTN and G3 CKD leads to a significant improvement in arterial stiffness, endothelial and renal function, and achievement of target BP in 90% of patients.

Video images captured at long range often show low-contrast floating objects of interest on a sea surface. A comparative experimental study of the statistical characteristics of reflections from floating objects and from the agitated sea surface showed differences in the correlation and spectral characteristics of these reflections. The functioning of the recently proposed modified matched subspace detector (MMSD) is based on the separation of the observed data spectrum on two subspaces: relatively low and relatively high frequencies. In the literature, the MMSD performance has been evaluated in general and using only a sea model (i.e., additive Gaussian background clutter). This paper extends the performance evaluating methodology for low contrast object detection using only a real sea dataset. The methodology assumes an object of low contrast if the mean and variance of the object and the surrounding background are the same. The paper assumes that the energy spectrum of the object and the sea are different. The paper investigates a scenario in which an artificially created model of a floating object with specified statistical parameters is placed on the surface of a real sea image. The paper compares the efficiency of the classical matched subspace detector (MSD) and MMSD for detecting low-contrast objects on the sea surface. The article analyzes the dependence of the detection probability at a fixed false alarm probability on the difference between the statistical means and variances of a floating object and the surrounding sea.

Multilayer YAG/Nd3+:YAG/YAG composite laser ceramics were obtained by the reactive sintering in vacuum. The effect of the neodymium ion concentration (1–4 at.%) on the formation of defects and optical quality of composite ceramics was studied. It was found that neodymium ions modify densification kinetics during solid-state reactive sintering of the highly-doped Nd3+:YAG ceramics by decreasing shrinkage rate in the temperature range 1320–1350 °C. Differences in phase transformation kinetics during reactive sintering lead to generation of pores at the interface of adjacent layers which decrease the optical homogeneity of fabricated YAG/Nd3+:YAG/YAG composite ceramics. The influence of layered structure on the laser performance of optical ceramics was investigated. It was shown that the ceramics with multilayer composite architecture have slope efficiency almost twice as the single-layer ceramics with the same composition (22% and 12.5%, respectively).

New data on continuing advance of the Kamchatka glaciers Erman, Vlodavets, Sopochny, Schmidt, and Bogdanovich were obtained as a result of analysis of aerospace information taken at different times. Glacier Erman advances during the past 70 years (1945–2016). Over the period from 1949 to 2016, its area increased by 4.7 km2 and the length – by 3.3 km (from 18.2 to 21.5 km). The highest speed of advancing had been estimated for the Schmidt glacier, in 2007–2013 it exceeded 100 m/year. We had identified a new isolated glacier between glaciers Erman and Schmidt, named as the Obvalny (the «Avalanche») glacier, since in 1945 this glacier was buried under volcanic-avalanche deposits resulted from the Klyuchevskaya volcano eruption. In 1975–2016, the Obvalny glacier advanced over a distance of about 1700 m. Also, we had found more 30 ice-rock massifs («wandering glaciers») on slopes of the Klyuchevskaya volcano. Their contours looked like drops or tongues, and some of them advanced in the frontal zone. From 2002 to 2016, the «wandering glacier» in the upper reaches of river Glubokaya (eastern sector of the volcano) advanced for 740 m (55 m/year). Advancing of glaciers here is a consequence of lateral and terminal eruptions of the Klyuchevskaya volcano in XX and XXI centuries. Erman Glacier, glacier advance, Klyuchevskaya volcano, lateral eruption, space images, volcanic and rock avalanche deposits, «wandering glaciers».

The relevance of the research is caused by the lack of study of relations between relief and construction of gas transportation systems. The decision of scientific and applied engineering problems, such as choice of optimal route for pipelines, design of measures for engineering protection of facilities and land reclamation, planning of monitoring areas of gas transportation systems, requires an assessment of engineering and geomorphological conditions. This study represents regional-scaled experience of such an assessment. The aim of this work is the regional engineering geomorphological assessment of the area of gas transportation systems passage (for example, the site of the proposed gas pipeline in the Saratov region). The assessment was carried out by morphometric, morpholithologic, morphodynamic and complex criteria applicable at the regional scale level. Methods: cartographic method, comparative-geographical method, field geomorphological and landscape mapping, morphometric and statistical analysis, morpholithogenesis analysis, GIS analysis (using radar digital topographic database SRTM), interpretation of space images. Graphics and design build was performed by using MS Office, ArcGIS, AutoCAD and Global Mapper. Results. The author has carried out regional engineering assessment of the relief for the route of gas transportation systems in Saratov region. At the site selected for regional assessment, the most difficult geomorphological areas are presented at the crossings of river valleys. The slopes and bottoms of the valleys, alternating with the watershed areas, determine the route differentiation by morpholithological and morphodynamic conditions. The Northern part of the territory is more favorable in terms of the terrain dissection along the route. At the same time, in the South (in the Lysogorsky district) there is more developed transport infrastructure.