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Summary: Protein-protein interactions (PPIs) play central roles in orchestrating biological processes. While some PPIs are stable, many important ones are transient and hard to detect with conventional approaches. We developed ReBiL, a recombinase enhanced bimolecular luciferase complementation platform, to enable detection of weak PPIs in living cells. ReBiL readily identified challenging transient interactions between an E3 ubiquitin ligase and an E2 ubiquitin-conjugating enzyme. ReBiL’s ability to rapidly interrogate PPIs in diverse conditions revealed that some stapled α-helical peptides, a class of PPI antagonists, induce target-independent cytosolic leakage and cytotoxicity that is antagonized by serum. These results explain the requirement for serum-free conditions to detect stapled peptide activity, and define a required parameter to evaluate for peptide antagonist approaches. ReBiL’s ability to expedite PPI analysis, assess target specificity and cell permeability, and reveal off-target effects of PPI modifiers should facilitate the development of effective, cell-permeable PPI therapeutics and the elaboration of diverse biological mechanisms. : Li et al. developed a recombinase-enhanced bimolecular luciferase complementation platform, termed ReBiL, to evaluate low-affinity protein-protein interactions (PPIs) that are not detectable by other methods and to analyze PPI antagonists in living cells. ReBiL showed that small-molecule p53-Mdm2 antagonists disrupt their intended targets effectively in cells, whereas stapled peptides did not. Stapled peptides unexpectedly induced cell membrane disruption resulting in p53-independent death associated with cytoplasmic leakage. ReBiL is also valuable for high-throughput screening and for deciphering signaling mechanisms mediated by protein interactions.

The paper is concerned with experimental aerodynamic research on the midsection of a 1220 mm long turbine rotor blade. Optical as well as pneumatic measurements of the midsection blade cascade have been performed in a suction type high-speed wind tunnel. The results of measurements are analyzed and discussed. Interferograms and schlieren pictures taken in a wide range of isentropic exit Mach numbers and incidence angles exhibit the existence of several phenomena occurring in the transonic flow field at certain conditions concerning the exit Mach number and the angle of incidence. A flow separation taking place at an extreme negative incidence has been found to produce an additional loss of 6%. The presence of the reflection of an exit shock wave on the suction side of the neighbouring profile has been found to have a substantial influence on the losses, since the loss coefficient value has increased about 10% in cases without the reflection, i.e. the cases at a high exit Mach number and a high positive angle of incidence. Several reflection types have been observed and described.

This paper deals with the study of a flow field and namely the configuration of shock waves in a blade cascade equipped with a part-span connector called tie-boss. The cascade consists of prismatic blades formed from the mid-section of a very long last-stage blade of a steam turbine. The study is based on numerical simulations of the flow through a cascade that was previously tested in a wind tunnel. Commercial software Ansys CFX was used for the simulations and Ansys ICEM for the mesh generation. The computational domain contains non-homogenous mesh interfaces. The simulations showed that the presence of the tie-boss has a profound effect on the configuration of the shock waves. The blade exit shock waves are disturbed and new lateral shock waves are introduced into the flow.

This paper deals with the numerical simulation of 2D transonic flow through the SE1050 turbine blade cascade at various flow conditions. The first one concerns the design operation with a zero incidence angle involved in the ERCOFTAC Database CFD-QNET and the second one with a +20° incidence angle corresponding to an off-design operation. Advanced mathematical models with two different models of the bypass transition to turbulence were applied for the simulation of different regimes of transonic flows as well as with attached and separated flows. Transition models proposed by Dick et al. [1] and by Menter and Smirnov [2] are based on transport equations for the intermittency coefficient. Numerical results were compared with experimental data based on the optical and pressure measurements.

This paper presents new results of computational experiments on the implementation of Overfire Air (OFA) technologies using an example of a combustion chamber of the BKZ-75 boiler of the Shakhtinskaya power plant (Shakhtinsk, Kazakhstan) burning high-ash Karaganda coal. The effect of mass air flow through special nozzles located above the burner level on the flow aerodynamics, temperature fields, concentration fields of carbon monoxide CO and nitrogen NO over the entire volume of the combustion chamber was studied. The studied characteristics were compared for various percentages of supplying additional air through OFA injectors: OFA is 0% (basic version), 10% and 18 %. It was shown that the installation of OFA injectors leads to a change in the field of the total velocity vector, temperature, and concentrations of carbon oxides and nitrogen. An increase in the percentage of air supplied through OFA injectors to 18% leads to a decrease in the concentrations of carbon monoxide CO by about 36% and nitrogen oxide NO by 25% compared with the base case. The obtained results will optimize the process of burning pulverized fuel in the combustion chamber of the BKZ-75 boiler, increase the efficiency of fuel burnout, reduce harmful emissions and introduce OFAtechnology at other coal-burning thermal power plants.

In this work, a comprehensive study of thermal processes and aerodynamic and concentration characteristics of the combustion chamber of the boiler BKZ-75 of the Shakhtinskaya thermal power plant (Kazakhstan) are presented. A comparison of the characteristics of the combustion processes for two cases is given for the direct-flow method of supplying the mixture - the burners are located on opposite-side walls and the swirl-air mixture supplying method - burners with a swirl angle of the air mixture flow and their inclination to the centre of symmetry of the boiler by 30 degrees. The research results allow us to determine the optimal technological parameters of the studied object, to improve the methodology for the numerical study of heat and mass transfer processes in high-temperature and chemically reacting flows in the presence of turbulence, and also develop appropriate technological solutions for installing burner devices (direct-flow or swirl) in the studied combustion chamber.

The aim of the work is to create new computer technologies for 3D modelling of heat and mass transfer processes in high-temperature physicochemically reacting environments that will allow to determine the aerodynamics of the flow and heat and mass transfer characteristics of technological processes occurring in the combustion chambers in existing coal-fired thermal power plants of the Republic of Kazakhstan. The novelty of the research lies in the use of the latest information technologies of 3D modelling, which will enable project participants to obtain new data on complex heat and mass transfer processes when burning pulverized coal in real combustion chambers operating in Kazakhstan’s Thermal Power Plants (TPP). A numerical simulation, including thermodynamic, kinetic and threedimensional computer simulation of heat and mass transfer processes when burning low-grade fuel, will allow finding optimal conditions for setting adequate physical, mathematical and chemical models of the technological process of combustion of burning high ash coals. The computer modelling methods proposed for the development are new and technically feasible, since coal-fired power plants all over the world use all types of coal. The developed technologies will allow replacing or eliminating the conduct of expensive and labour-consuming natural experiments on coal-fired power plants.

A study of the speed of sound in a pure water substance is presented here. The IAPWS data on the state of water and steam are applied only for investigating the speed of sound for a one-phase medium. A special numerical model for investigating the parameters of shock waves in steam is presented here and is applied for investigating extremely weak waves to obtain velocities representing the speed of sound in both one-phase and two-phase steam. Problems with the speed of sound in two-phase steam are discussed, and three types of speed of sound are derived for the metastable region of wet steam.

Transonic flow past two cusped airfoils is numerically solved and achieved results are analyzed by means of flow behavior and oblique shocks formation.Regions around sharp trailing edges are studied in detail and parameters of shock waves are solved and compared using classical shock polar approach and verified by reduction parameters for symmetric configurations.

The paper deals with problems of transonic flow field periodicity downstream of a profile cascade with finite number of blades. The origin of phenomena generating this aperiodicity in transonic wind tunnel is described. The solution of this problem by means of adjustable perforated tailboard is documented by results of optical measurements (interferometry, schlieren methods) on a turbine profile cascade consisting of six blades only. The conditions of formation of limit load regime are described.