Tectonics of the Greater Caucasus and the Arabia-Eurasia Orogen.

The new thermochronometric dataset presented in this dissertation unequivocally shows a 5 Ma onset of rapid exhumation throughout the Greater Caucasus. Patterns of exhumation rule out the possibility of climate being a major cause of the accelerated erosion and point to a tectonic forcing. Asymmetric exhumation with higher rates on the southern front of the Greater Caucasus agrees with the south-verging structure of the orogen and suggests that the uplift is the result of thrusting of Eurasia over the Transcaucasus that, thus, began in Pliocene time. Sedimentologic observations, in combination with thermochronometric data, led to the conclusion that the onset of thrusting in the Greater Caucasus resulted from collision between Transcaucasus and Eurasia, following closure of the Greater Caucasus back-arc basin. Subduction of the Greater Caucasus basin, therefore, provided a mechanism for a previously puzzling fact of the existence of a high mountain range far away from the Neotethyan suture. The paradox of the western Greater Caucasus, where high elevations and deep levels of exhumation are associated with low seismicity and little active shortening is resolved. An estimate for a long-term (Ma) rate of overthrusting on the Main Caucasus fault derived from a thermokinematic model constrained by thermochronometric and seismic data agrees with the active rate of convergence derived from geodetic observations. The rapid exhumation is a result of highly focused deformation occurring on a steeply dipping fault. Such kinematics is likely dictated by a competent rheology of the ancient crust of the western Transcaucasus and Eurasia. The final chapter provides a development of the detrital thermochronometric methodology with a new method for estimating erosion models describing short-term spatial patterns of erosion and long-term history of denudation. This approach allows thermochronometric studies of terrains inaccessible for bedrock sampling and is useful in the Greater Caucasus, where the axis of the range coincides with three international borders.Ph.D.GeologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/86342/1/borya_1.pd

Widespread late Cenozoic increase in erosion rates across the interior of eastern Tibet constrained by detrital low-temperature thermochronometry

New detrital low-temperature thermochronometry provides estimates of long-term erosion rates and the timing of initiation of river incision from across the interior of the Tibetan Plateau. We use the erosion history of this region to evaluate proposed models of orogenic development as well as regional climatic events. Erosion histories of the externally drained portion of the east-central Tibetan Plateau are recorded in modern river sands from major rivers across a transect that spans >750 km and covers a region with no published thermochronometric ages. Individual grains from eight catchments were analyzed for apatite (U-Th)/He and fission track thermochronometry. A wide distribution in ages that, in most cases, spans the entire Cenozoic and Late Mesozoic eras requires a long period of slow or no erosion with a relative increase in erosion rate toward the present. We apply a recently developed methodology for inversion of detrital thermochronometric data for three specified erosion scenarios: constant erosion rate, two-stage erosion history, and three-stage erosion history. Modeling results suggest that rates increase by at least an order of magnitude between 11 and 4 Ma following a period of slow erosion across the studied catchments. Synchroneity in accelerated erosion across the whole of the Tibetan Plateau rather than a spatial or temporal progression challenges the widely held notion that the plateau evolved as a steep, northward-propagating topographic front, or that south to north precipitation gradients exert a primary control on erosion rates. Instead, we suggest that accelerated river incision late in the orogen's history relates to regional-scale uplift that occurred in concert with eastern expansion of the plateau

Relict basin closure and crustal shortening budgets during continental collision: An example from Caucasus sediment provenance

Comparison of plate convergence with the timing and magnitude of upper crustal shortening in collisional orogens indicates both shortening deficits (200–1700 km) and significant (10–40%) plate deceleration during collision, the cause(s) for which remains debated. The Greater Caucasus Mountains, which result from postcollisional Cenozoic closure of a relict Mesozoic back‐arc basin on the northern margin of the Arabia‐Eurasia collision zone, help reconcile these debates. Here we use U‐Pb detrital zircon provenance data and the regional geology of the Caucasus to investigate the width of the now‐consumed Mesozoic back‐arc basin and its closure history. The provenance data record distinct southern and northern provenance domains that persisted until at least the Miocene. Maximum basin width was likely ~350–400 km. We propose that closure of the back‐arc basin initiated at ~35 Ma, coincident with initial (soft) Arabia‐Eurasia collision along the Bitlis‐Zagros suture, eventually leading to ~5 Ma (hard) collision between the Lesser Caucasus arc and the Scythian platform to form the Greater Caucasus Mountains. Final basin closure triggered deceleration of plate convergence and tectonic reorganization throughout the collision. Postcollisional subduction of such small (102–103 km wide) relict ocean basins can account for both shortening deficits and delays in plate deceleration by accommodating convergence via subduction/underthrusting, although such shortening is easily missed if it occurs along structures hidden within flysch/slate belts. Relict basin closure is likely typical in continental collisions in which the colliding margins are either irregularly shaped or rimmed by extensive back‐arc basins and fringing arcs, such as those in the modern South Pacific.Key PointsU‐Pb provenance indicates Greater Caucasus formed by postcollisional Cenozoic closure of a Mesozoic back arc basin likely ~350–400 km widePostcollisional subduction/underthrusting of such relict basins helps account for shortening deficits and delayed plate decelerationPlate convergence should not be expected to balance upper crustal shortening or the length of subducted slab following collisionPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135981/1/tect20504.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135981/2/tect20504_am.pd

Rapid Pliocene exhumation of the central Greater Caucasus constrained by low‐temperature thermochronometry

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94839/1/tect2241.pd

Practical recommendations for choosing an immunobiological preparation for the treatment of severe bronchial asthma of T2-endotype

Biological therapy of bronchial asthma (BA) is a modern method of treating severe forms of the disease, that are uncontrolled by traditional pharmacotherapeutic approaches. Currently, 5 monoclonal antibody (AT) preparations are registered in the world for the treatment of severe bronchial asthma (SBA) of the T2 endotype (T2-SBA) – antibodies, binding to immunoglobulin (Ig) E (anti-IgE – omalizumab), interleukin antagonists (IL)-5 (anti-IL-5 – mepolizumab, resizumab) and its receptor (anti-IL-5Rα – benralizumab), as well as antibodies, that selectively bind to the IL-4 and -13 receptor (anti-IL-4 /13Rα – dupilumab). The article presents data on the effectiveness of these drugs in relation to the key characteristics of SBA, formulates clinical and laboratory criteria, the study of which in real practice can potentially predict the likelihood of a clinical response to a particular type of biological therapy. An algorithm is proposed for choosing a targeted therapy strategy for patients with SBA, clinically associated with allergies, for patients with severe non-allergic eosinophilic BA and for patients with eosinophilic BA of a combined phenotype.Биологическая терапия бронхиальной астмы (БА) представляет собой современный метод лечения тяжелых форм заболевания, неконтролируемых при помощи традиционных фармакотерапевтических подходамов. В настоящее время в мире зарегистрированы 5 препаратов моноклональных антител (АТ) для лечения тяжелой бронхиальной астмы (ТБА) Т2-эндотипа (Т2-ТБА) – АТ, связывающие иммуноглобулин (Ig) Е (анти-IgE – омализумаб), антагонисты интерлейкина (IL)-5 (анти-IL-5 – меполизумаб, реслизумаб) и его рецептора (анти-IL-5Rα – бенрализумаб), а также АТ, избирательно связывающиеся с рецептором IL-4 и -13 (анти-IL-4/13Rα – дупилумаб). В статье приведены данные об эффективности указанных препаратов в отношении ключевых характеристик ТБА, сформулированы клинико-лабораторные критерии, при исследовании которых в реальной практике потенциально может быть предсказана вероятность клинического ответа на тот или иной вид биологической терапии. Предложен алгоритм выбора стратегии таргетной терапии для пациентов с ТБА, клинически ассоциированной с аллергией, для больных тяжелой неаллергической эозинофильной БА и для страдающих эозинофильной БА сочетанного фенотип

Laboratory studies of the operation of a single-phase solid-state transformer when operating from a wind turbine

The article describes a laboratory equipment for studying the operation of a single-phase solid-state transformer when operating from a wind turbine. Oscillograms of currents and oscillograms of voltages are given during the operation of a solid-state transformer from a voltage source. To simulate a wind turbine, the "actuating mechanism - generator" assembly was used. Wind gusts were simulated using a frequency converter. The key elements of the solid-state transformer - a dual active bridge - were controlled by the phase shift method. Critical points were found that could not be foreseen in a theoretical or simulation study. The experiment showed the perspective of using new technologies to maintain a stable output voltage frequency and voltage level

Improving the Electricity Quality by Means of a Single-Phase Solid-State Transformer

The paper describes the use of a single-phase three-stage solid-state transformer in networks with non-sinusoidal voltages in order to improve the quality of electricity. An active-inductive load was chosen as the load. The solid-state transformer was simulated by the Matlab/Simulink software. Its performance was analyzed and the parameters for optimal performance were specified. The voltage and current graphs on the load and their spectral analysis are given. Total harmonic distortion was evaluated for current and voltage. As a comparison, the operation of a classic transformer was simulated. Modeling shows that solid-state transformer copes with improving the quality of electricity better than a classical transformer. In addition to improving the quality of the load current, the solid-state transformer protects the consumer from overvoltage, voltage dips, and other transient phenomena, due to the accumulated supply of electricity in the capacitors of the DC-Bus

Pulmonary Fibrosis and Progressive Pulmonary Fibrosis in a Prospective Registry of Interstitial Lung Diseases in Eastern Siberia

Interstitial lung diseases (ILD) are part of a large heterogeneous group of diseases that differ in many ways (in their cause, clinical presentation, and response to therapy, etc.), but there are similar pathophysiological mechanisms involved in the development of the inflammation and/or fibrosis of the lungs. Currently, several criteria for pulmonary fibrosis (PF) and progressive pulmonary fibrosis (PPF) are proposed, and the information on the prevalence and characteristics of these conditions is limited. The aim of this study was to evaluate the spectrum of PF and PPF according to the registry of patients with ILD in eastern Siberia. Materials and methods: The study included patients with ILD from all of the medical institutions in the Irkutsk region (eastern Siberia). Each case of ILD (n = 270) was reviewed by a multidisciplinary discussion panel. The ILD patient registry included information on the clinical findings, history, pulmonary function tests, high-resolution computed tomography (HRCT), and histological findings. The follow-up period for the patients varied from 1 to 5 years. Results: Pulmonary fibrosis was detected by HRCT in 104 patients with ILD (38.5%). PF was present in 100% of the patients with IPF and SS-ILD, in 90.9% of the patients with CHP, in 71.4% of the patients with NSIP, and in 60% of the patients with RA-ILD. Sixty-two patients met the criteria for PPF (23.0% of the entire ILD cohort and 59.6% of the patients with PF). PPF occurred most often in the patients with IPF, CHP, IPAF, and SSc-ILD: 100%, 72.7%, 40%, and 38.5% of them, respectively. The variables associated with fibrosis progression included Velcro crackles (OR 18.3, p p < 0.001). Conclusion: Pulmonary fibrosis and progressive pulmonary fibrosis are common in patients with ILD. The high mortality rate of PPF dictates the need for the active, early detection of a progressive fibrosing course of a wide range of ILD and suggests that further studies assessing the effectiveness of the interventions might be warranted

Fast-Processable Non-Flammable Phthalonitrile-Modified Novolac/Carbon and Glass Fiber Composites

Phthalonitrile resins (PN) are known for their incredible heat resistance and at the same time poor processability. Common curing cycle of the PN includes dozens hours of heating at temperatures up to 375 &deg;C. This work was aimed at reducing processing time of phthalonitrile resin, and with this purpose, a novolac oligomer with hydroxyl groups fully substituted by phthalonitrile moieties was synthesized with a quantitative yield. Formation of the reaction byproducts was investigated depending on the synthesis conditions. The product was characterized by 1H NMR and FT-IR. Curing of the resins with the addition of different amounts of novolac phenolic as curing agent (25, 50 and 75 wt.%) was studied by rheological and DSC experiments. Based on these data, a curing program was developed for the further thermosets&rsquo; investigation: hot-pressing at 220 &deg;C and 1.7 MPa for 20 min. TGA showed the highest thermal stability of the resin with 25 wt.% of novolac (T5% = 430 &deg;C). The post-curing program was developed by the use of DMA with different heating rates and holding for various times at 280 or 300 &deg;C (heating rate 0.5 &deg;C/min). Carbon and glass fiber plastic laminates were fabricated via hot-pressing of prepregs with Tg&rsquo;s above 300 &deg;C. Microcracks were formed in the CFRP, but void-free GFRP were fabricated and demonstrated superior mechanical properties (ILSS up to 86 MPa; compressive strength up to 620 MPa; flexural strength up to 946 MPa). Finally, flammability tests showed that the composite was extinguished in less than 5 s after the flame source was removed, so the material can be classified as V-0 according to the UL94 ratings. For the first time, fast-curing phthalonitrile prepregs were presented. The hot-pressing cycle of 20 min with 150 min free-standing post-curing yielded composites with the unique properties. The combination of mechanical properties, scale-up suitable fast-processing and inflammability makes the presented materials prospective for applications in the electric vehicle industries, fast train construction and the aerospace industry