Membrane proteins (MPs) play vital roles in the function of cells and are also major drug targets. Structural information on proteins is vital for understanding their mechanism of function and is ...critical for the development of drugs. However, obtaining high‐resolution structures of membrane proteins, in particular, under native conditions is still a great challenge. In such cases, the low‐resolution methods small‐angle X‐ray and neutron scattering (SAXS and SANS) might provide valuable structural information. However, in some cases small‐angle scattering (SAS) provides ambiguous ab initio structural information if complementary measurements are not performed and/or a priori information on the protein is not taken into account. Understanding the nature of the limitations may help to overcome these problems. One of the main problems of SAS data analysis of solubilized membrane proteins is the contribution of the detergent belt surrounding the MP. Here, a comprehensive analysis of how the detergent belt contributes to the SAS data of a membrane‐protein complex of sensory rhodopsin II with its cognate transducer from Natronomonas pharaonis (NpSRII–NpHtrII) was performed. The influence of the polydispersity of NpSRII–NpHtrII oligomerization is the second problem that is addressed here. It is shown that inhomogeneity in the scattering length density of the detergent belt surrounding a membrane part of the complex and oligomerization polydispersity significantly impacts on SAXS and SANS profiles, and therefore on 3D ab initio structures. It is described how both problems can be taken into account to improve the quality of SAS data treatment. Since SAS data for MPs are usually obtained from solubilized proteins, and their detergent belt and, to a certain extent, oligomerization polydispersity are sufficiently common phenomena, the approaches proposed in this work might be used in SAS studies of different MPs.
Ambiguities in and the completeness of SAS data analysis of membrane proteins (MPs) are considered here in the case of the sensory rhodopsin II–transducer complex solubilized in a detergent. The contribution of the detergent belt surrounding MPs is one of the main problems in SAS data analysis of MPs; the second problem addressed here is the influence of oligomerization polydispersity (which is a sufficiently common phenomenon for MPs) on the quality of SAS structural analysis.
Postulated conformers of trifluoromethylated β-aminoenones stabilized by intramolecular NH⋯O and N⋯HO bonds were studied by IR and NMR spectroscopy and evaluated with quantum chemical calculations ...(B3LYP/6-311+G(d,p), MP2/6-311+G(d,p)//B3LYP/6-311+G(d,p) and MP2/6-31G(d,p)) and NBO analysis. The influence of the nature of EWG, substituents at the nitrogen atom and double bond, and of orbital interactions of heteroatoms and double bonds in these structures on the proton affinity of basic and acid centers, strength of hydrogen bonds, and the energy of tautomeric transfers is discussed. The theoretical results agree satisfactorily with the experimental observations.
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•A diverter based on flowing lithium layer concept allows to reduce fuel recycling.•HIP diffusion bonding provides a reliable Cu/SS joint for divertor receiving plate.•HIP-made Cu/SS plate with ...cooling channels withstood a heat flux up to 11.9 MW/m2.•HIP-made Cu/SS plate with cooling channels withstood 1000 thermal cycles at 8 MW/m2.
A prospective technology for manufacture of the tokamak divertor target based on the concept of flowing liquid lithium layer is described. A small-size bimetal plate was produced by the hot isostatic pressing diffusion bonding of a thick solid copper base, which serves as a thermal sink, and a thin (0.2 mm) stainless-steel foil, which serves as a corrosion-resistance coating. The mock-up with cooling channels in the copper sink was tested by loading the stainless-steel surface by a high heat flux in two loading modes. First, the absorbed heat flux density was increased step-by step from 0.5 MW/m2 to 11.9 MW/m2. Second, thermocycling (1000 cycles) at an absorbed heat-flux density of about 8 MW/m2 was performed. The mock-up demonstrated acceptable uniformity of the temperature on the surface without spot overheating and good stability in thermal cycling in the range of RT-500 °C. No defects were observed after the tests performed.
When using renewable heat sources that have limited volumetric heat capacity, for example, air, water, gases, the temperature of which changes significantly during cooling in the evaporator and ...heating in the condenser, execution of cycles for heat pumps operating on zeotropic mixtures, the temperature of which also changes, makes it possible to increase their energy efficiency. The paper proposes a technique for thermal calculation of counter-flow tube-type evaporators and heat pump condensers which use media with limited volumetric heat capacity as heat sources, and zeotropic mixtures as working substances. We carried out experimental corroboration of the proposed technique for thermal calculation of counter-flow tube-type evaporators and heat pump condensers, which confirms the validity of the developed mathematical equations of heat transfer in the "medium with limited volumetric heat capacity, i.e. propane-butane zeotropic mixture" system. Average deviation of experimental data from theoretical dependencies with a confidence level of 95% is 27.6%, which makes it possible to recommend them for use in design and operational practice.
The work is a review of neutronographic investigations of supramolecular structures on upgraded small-angle spectrometer YuMO. Here, key parameters of small-angle spectrometers are considered. It is ...shown that two-detector system is the basis of YuMO upgrade. It allows to widen the dynamic q-range twice. In result, the available q-range is widened and dynamic q-range and data collection rate are doubled. The detailed description of YuMO spectrometer is given.The short review of experimental researches made on the spectrometer in the polymers field, biology, material science and physical chemistry is given. The current investigations also have a methodological aspect. It is shown that upgraded spectrometer provides advanced world level of research of supramolecular structures.
•The permissible beryllium tile size, size of defects in the bonding interface, and load on the tile edges were verified by experiments.•Critical technologies of beryllium-armoured component have ...been successfully qualified by the ITER organization.•The mock-ups with beryllium armour withstood 30,000 cycles at 4.7 MW/m2.•A full-scale prototype of the ITER enhanced-heat flux first wall panel has been manufactured, inspected and tested.
The Russian Federation shall supply 179 enhanced heat flux First Wall Panels (FWP) to the ITER construction site. These panels have about 30 types and consist of a steel supporting structure (FW Beam) with multilayer plasma-facing units (PFU) attached onto it. To start the production of the panels, the manufacturing readiness must be confirmed by the ITER Organization (IO). The JSC “NIIEFA” responsible for manufacturing of a part of the components, final assembly and testing of the panels has come a long way from the experimental work on small-scale mock-ups, through the development of the design and key manufacturing technologies to the production and testing of the full-scale prototype (FSP) which is the final step before the confirmation for the manufacture. The manufactured FSP has successfully passed most of the acceptance tests including hydraulic pressure and leak tightness tests. The high heat flux tests have been successfully carried out on the PFUs with beryllium armour. In parallel to the tests of the beryllium prototype, the tungsten armour has been analyzed and tested which is due to the IO's intention to change the armour material.
Using a multidetector system on the YuMO spectrometer allows shortening the time of measurements. The quantitative comparison of the measurement time using one and two-detector mode is done. The time ...range for experiments was from several minutes up to 12 hours. It was shown that two-detector system shortens more than twice the time of the measurement. While making a structural investigation using advanced software the two-detector system allows to treat the data at a qualitatively new level. An example illustrating the features of the channels choice and measurement time on the spectrometer was shown. The results of this paper could be used when planning the experiments on the YuMO spectrometer, for modernization of the installation and for equipment using time-of-flight method.
The article presents operation principles and calculation methods for compression heat pumps using zeotropic mixtures as working fluids. It proposes the principle and methodological provisions for ...achieving the minimum value of mean condensation and boiling temperatures difference by selecting the molar concentration value for the low-boiling component of the zeotropic mixture out of two components that are close in their physical properties, and taking into account saturation temperature change in the condenser and evaporator of the heat pump, depending on the relative amount of the boiled out mixture and limited heat capacity heated and cooled mediums temperature changes. The authors developed a thermal calculation model for flow tubular condensers and evaporators of the zeotropic mixture, which allows to take into account the intensity of heat exchange changes and temperature conditions depending on the continuously changing composition and flow regimes of the vapor-liquid mixture taking place in the following sequence: dispersed, circular wave and layered-plug flow modes.
Abstract
We report the discovery of a new unidentified extended
γ
-ray source in the Galactic plane named LHAASO J0341+5258 with a pretrial significance of 8.2 standard deviations above 25 TeV. The ...best-fit position is R.A. = 55.°34 ± 0.°11 and decl. = 52.°97 ± 0.°07. The angular size of LHAASO J0341+5258 is 0.°29 ± 0.°06
stat
± 0.°02
sys
. The flux above 25 TeV is about 20% of the flux of the Crab Nebula. Although a power-law fit of the spectrum from 10 to 200 TeV with the photon index
α
= 2.98 ± 0.19
stat
± 0.02
sys
is not excluded, the LHAASO data together with the flux upper limit at 10 GeV set by the Fermi-LAT observation, indicate a noticeable steepening of an initially hard power-law spectrum with a cutoff at ≈50 TeV. We briefly discuss the origin of ultra-high-energy gamma rays. The lack of an energetic pulsar and a young supernova remnant inside or in the vicinity of LHAASO J0341+5258 challenge, but do not exclude, both the leptonic and hadronic scenarios of gamma-ray production.
Abstract
The paper substantiates the construction and location of differential pressure sensors for a coarse and fine gas energy-saving plant. Energy saving is achieved by installing filtering ...cylindrical elements of fine and coarse purification one inside the other, optimizing their shape and substantiating the location of the differential pressure sensors. The results of the studies show that the total specific heat consumption for heating and ventilation of purification plants from all energy-saving measures for the proposed option is 1.85 times lower than the existing analogue of the non-optimized shape and measuring the pressure drop at the inlet and outlet branch pipes. The article also proved that the static gas pressure in the lower part of filter elements of the coarse and fine purification will always be higher than in their upper part. This results in a proportionally higher amount of inlet gas and therefore more solids settling in the bottom of the filter element. Measurement of the pressure drop in the lower part of the filter element, the most clogged with solid particles, makes it possible to receive a signal at the dispatching console earlier and provides a time reserve for technical personnel to timely remove accumulated blockages from coarse purification elements and prompt replacement of fine purification elements.
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