251 research outputs found
Structure formation of TiB2-TiC-B4C-C hetero-modulus ceramics via reaction hot pressing
The densification kinetics and structure of TiB2-TiC-C, TiB2-C and TiB2-B4C-C hetero-modulus ceramics produced via reaction hot-pressing of B4C and TiС precursors are investigated. The reaction begins at 1100°C with boron carbide decomposition and progresses in two main stages which can be predominantly determined by the boron atoms to TiC grains diffusion mechanisms. The solid phase grain boundary diffusion starts at 1100°C and effective gas phase transport finalises the reaction at temperatures above 1400°C. Two distinctive waves of the charge consolidation allow densifying investigated refractory materials at 1900°C and 30MPa during 16 minutes. The reaction is shown to define the features of the composite structure: submicron TiB2 particles and faceted voids in B4C matrix, flake-like graphite and TiB2 inclusions in TiC matrix. High concentration of carbon atoms (~ 10 at.%) in synthesized diboride titanium grains have been observed
Biofuel cell based on microscale nanostructured electrodes with inductive coupling to rat brain neurons.
Miniature, self-contained biodevices powered by biofuel cells may enable a new generation of implantable, wireless, minimally invasive neural interfaces for neurophysiological in vivo studies and for clinical applications. Here we report on the fabrication of a direct electron transfer based glucose/oxygen enzymatic fuel cell (EFC) from genuinely three-dimensional (3D) nanostructured microscale gold electrodes, modified with suitable biocatalysts. We show that the process underlying the simple fabrication method of 3D nanostructured electrodes is based on an electrochemically driven transformation of physically deposited gold nanoparticles. We experimentally demonstrate that mediator-, cofactor-, and membrane-less EFCs do operate in cerebrospinal fluid and in the brain of a rat, producing amounts of electrical power sufficient to drive a self-contained biodevice, viz. 7 μW cm(-2) in vitro and 2 μW cm(-2) in vivo at an operating voltage of 0.4 V. Last but not least, we also demonstrate an inductive coupling between 3D nanobioelectrodes and living neurons
Distinctive features of diffusion-controlled radiation defect recombination in stoichiometric magnesium aluminate spinel single crystals and transparent polycrystalline ceramics
This work has been performed within the framework of the EUROfusion Enabling Research project: ENR-MFE19.ISSP-UL-02 “Advanced experimental and theoretical analysis of defect evolution and structural disordering in optical and dielectric materials for fusion application”. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Research of A.L, E.F.,, V.S and E.S has been partly supported by the Estonian Research Council grant (PUT PRG619); has been also carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 and 2019–2020 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.MgAl2O4 spinel is important optical material for harsh radiation environment and other important applications. The kinetics of thermal annealing of the basic electron (F, F+) and hole (V) centers in stoichiometric MgAl2O4 spinel irradiated by fast neutrons and protons is analyzed in terms of diffusion-controlled bimolecular reactions. Properties of MgAl2O4 single crystals and optical polycrystalline ceramics are compared. It is demonstrated that both transparent ceramics and single crystals, as well as different types of irradiation show qualitatively similar kinetics, but the effective migration energy Ea and pre-exponent D0 are strongly correlated. Such correlation is discussed in terms of the so-called Meyer-Neldel rule known in chemical kinetics of condensed matter. The results for the irradiated spinel are compared with those for sapphire, MgO and other radiation-resistant materials.Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART
The front-end electronics for the COMPASS MWPCs
In the COMPASS experiment 34 planes of MWPCs for about 26,000 readout channels of MWPCs are used. The very high rate of the muon and hadron beams, and the consequently high trigger rate, requires the use of a front-end electronics with new conceptual design, to have a fast DAQ with a minimum dead-time. Its scheme will be described, together with some results of the performances achieved
Mapping of the immunodominant regions of the NAD-dependent formate dehydrogenase
AbstractA panel of 4 monoclonal antibodies and 7 polyclonal antisera against NAD-dependent formate dehydrogenase from methylotrophic bacterium Pseudomonas sp. 101 has been obtained. The reactivity of the 37 overlapping proteolytic peptides with the monoclonal antibodies and polyclonal antisera has been studied with ELISA test. The data obtained were interpreted residing on the structural model of the formate dehydrogenase at 3 Å resolution. The immunodominant regions in the formate dehydrogenase molecule and the epitopes for the monoclonal antibodies were elucidated
NADP-Dependent Aldehyde Dehydrogenase from Archaeon Pyrobaculum sp.1860
We present the functional and structural characterization of the first archaeal thermostable NADP-dependent aldehyde dehydrogenase AlDHPyr1147. In vitro, AlDHPyr1147 catalyzes the irreversible oxidation of short aliphatic aldehydes at 60–85°С, and the affinity of AlDHPyr1147 to the NADP+ at 60°С is comparable to that for mesophilic analogues at 25°С. We determined the structures of the apo form of AlDHPyr1147 (3.04 Å resolution), three binary complexes with the coenzyme (1.90, 2.06, and 2.19 Å), and the ternary complex with the coenzyme and isobutyraldehyde as a substrate (2.66 Å). The nicotinamide moiety of the coenzyme is disordered in two binary complexes, while it is ordered in the ternary complex, as well as in the binary complex obtained after additional soaking with the substrate. AlDHPyr1147 structures demonstrate the strengthening of the dimeric contact (as compared with the analogues) and the concerted conformational flexibility of catalytic Cys287 and Glu253, as well as Leu254 and the nicotinamide moiety of the coenzyme. A comparison of the active sites of AlDHPyr1147 and dehydrogenases characterized earlier suggests that proton relay systems, which were previously proposed for dehydrogenases of this family, are blocked in AlDHPyr1147, and the proton release in the latter can occur through the substrate channel
The mRubyFT Protein, Genetically Encoded Blue-to-Red Fluorescent Timer.
peer reviewedGenetically encoded monomeric blue-to-red fluorescent timers (mFTs) change their fluorescent color over time. mCherry-derived mFTs were used for the tracking of the protein age, visualization of the protein trafficking, and labeling of engram cells. However, the brightness of the blue and red forms of mFTs are 2-3- and 5-7-fold dimmer compared to the brightness of the enhanced green fluorescent protein (EGFP). To address this limitation, we developed a blue-to-red fluorescent timer, named mRubyFT, derived from the bright mRuby2 red fluorescent protein. The blue form of mRubyFT reached its maximum at 5.7 h and completely transformed into the red form that had a maturation half-time of 15 h. Blue and red forms of purified mRubyFT were 4.1-fold brighter and 1.3-fold dimmer than the respective forms of the mCherry-derived Fast-FT timer in vitro. When expressed in mammalian cells, both forms of mRubyFT were 1.3-fold brighter than the respective forms of Fast-FT. The violet light-induced blue-to-red photoconversion was 4.2-fold less efficient in the case of mRubyFT timer compared to the same photoconversion of the Fast-FT timer. The timer behavior of mRubyFT was confirmed in mammalian cells. The monomeric properties of mRubyFT allowed the labeling and confocal imaging of cytoskeleton proteins in live mammalian cells. The X-ray structure of the red form of mRubyFT at 1.5 Å resolution was obtained and analyzed. The role of the residues from the chromophore surrounding was studied using site-directed mutagenesis
Completion of the 8 MW Multi-Frequency ECRH System at ASDEX Upgrade
Over the last 15 years, the Electron Cyclotron Resonance Heating (ECRH) system at the ASDEX Upgrade tokamak has been upgraded from a 2 MW, 2 s, 140 GHz system to an 8 MW, 10 s, dual frequency system (105/140 GHz). Eight gyrotrons were in routine operation during the current experimental campaign. All gyrotrons are step-tunable operating at 105 and 140 GHz with a maximum output power of about 1 MW and 10 s pulse length. The system includes 8 transmission lines, mainly consisting of oversized corrugated waveguides (I.D. = 87 mm) with overall lengths between 50 and 70 meters including quasi-optical sections at both ends. Further improvements of the transmission lines with respect to power handling and reliability are underway
Динамика органной дисфункции и маркеров воспаления у пациентов с септическим шоком при мультимодальной гемокоррекции: мультицентровое, рандомизированное, контролируемое исследование
АКТУАЛЬНОСТЬ: Септический шок считается наиболее серьезным осложнением в интенсивной медицине и сопровождается значительной летальностью. Экстракорпоральная гемокоррекция может улучшить результаты лечения пациентов с септическим шоком. ЦЕЛЬ ИССЛЕДОВАНИЯ: оценка влияния гемокоррекции с помощью мультимодального адсорбента «Эфферон ЛПС» на динамику органной дисфункции и маркеры воспаления у пациентов с септическим шоком. МАТЕРИАЛЫ И МЕТОДЫ: Мультицентровое рандомизированное контролируемое исследование проведено в четырех медицинских организациях города Москвы (НИИ СП им. Н.Ф. Склифосовского ДЗМ, ГКБ № 1 им. Н.И. Пирогова ДЗМ, ГКБ им. С.С. Юдина ДЗМ, ГКБ № 68 им. В.П. Демихова ДЗМ) с марта 2021 г. по май 2022 г. В исследование включены 58 пациентов (29 мужчин и 29 женщин) с септическим шоком. Рандомизацию проводили в соотношении 2:1 (гемоперфузия: контроль). Не позднее 24 ч после включения пациента в исследование выполняли процедуры селективной гемоперфузии или использовали стандартную терапию. Гемосорбцию с использованием «Эфферон ЛПС» проводили двукратно, с интервалом 24,5 (23,3–26,0) ч. РЕЗУЛЬТАТЫ: Применение селективного гемосорбента «Эфферон ЛПС» позволило уже через 72 ч снизить тяжесть органной дисфункции у пациентов с септическим шоком с 7 до 3 баллов по шкале SOFA (Sequential Organ Failure Assessment) за счет улучшения гемодинамики, респираторной и почечной функции. В отличие от контрольной группы, в группе «Эфферон ЛПС» уже через 72 ч значимо снижался уровень С-реактивного белка (СРБ) в 1,5 раза, прокальцитонина (ПКТ) — в 2,7 раза, интерлейкина-6 — в 2,3 раза. Тяжесть органной дисфункции значимо коррелировала с уровнем СРБ (r = 0,346) и ПКТ (r = 0,444). Длительность госпитализации выживших пациентов составила 16,1 и 30,1 дня в группе «Эфферон ЛПС» и контрольной группе соответственно (p = 0,032). Потребность в проведении заместительной почечной терапии у выживших к 3-м суткам значимо снижалась с 73,7 до 33,3 % только в группе «Эфферон ЛПС», но не в контрольной группе. ВЫВОДЫ: Применение селективного гемосорбента «Эфферон ЛПС» позволило уменьшить выраженность системного воспаления и значимо снизить тяжесть органной дисфункции у пациентов с септическим шоком за счет улучшения показателей гемодинамики, газообмена и почечной функции
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