Photobleaching Reveals Heterogeneous Stoichiometry for Equinatoxin II Oligomers

Equinatoxin II (EqtII), a sea anemone cytolysin, is known to oligomerize to form pores that spontaneously insert into membranes. Crystallographic and cryo‐EM studies of structurally similar cytolysins offer contradictory evidence for pore stoichiometry. Here we used single‐molecule photobleaching of fluorescently labeled EqtII to determine the stoichiometry of EqtII oligomers in supported lipid bilayers. A frequency analysis of photobleaching steps revealed a log‐normal distribution of stoichiometries with a mean of 3.4±2.3 standard deviations. Comparison of our experimental data with simulations of fixed stoichiometries supports our observation of a heterogeneous distribution of EqtII oligomerization. These data are consistent with a model of EqtII stoichiometry where pores are on average tetrameric, but with large variation in the number of subunits in individual pores.     

The Bologna reform’s impacts on the scientific publication performance of Ph.D. graduates—the case of Slovenia

Scientometrics - In this paper, the impact of the Bologna reform is analyzed based on differences in scientific publication performance among the Ph.D. graduates that enrolled into doctoral study...     

Temperature and concentration dependence of the critical resolved shear stress of cadmium-zinc alloy single crystals

The increase of the critical resolved shear stress of cadmium single crystals by additions of zinc has been investigated in the temperature range 77 to 295 K. The temperature dependence of the critical resolved shear stress can be divided into two temperature regions. At all temperatures the critical resolved shear stress was found to increase withc ^2/3 wherec is the atomic concentration of zinc as solute. The concentration dependence of the plateau stress is explained according to the theory of Labusch [5].     

Sliding-mode motion controller with adaptive fuzzy disturbance estimation

This paper proposes a motion control scheme which belongs to the class of the control schemes known as sliding-mode control with disturbance estimation. A novel adaptive fuzzy disturbance estimator works as an estimator of a major part of robot dynamics. The adaptation algorithm is derived by using the Lyapunov stability theory and provides global asymptotic stability of the state errors, resulting in the sliding-mode regime. The structure of the disturbance estimator is optimized by the introduction of three fuzzy logic subsystems, based on the physical properties of the robot mechanism. This also significantly lowers the computational burden and enables real-time implementation. Performance of the proposed controller scheme, as well as some practical design aspects, are demonstrated by the control of a direct-drive robot.     

Simulations of Transformation Kinetics in a Multi-Pass Weld

This paper discusses the thermal welding cycle's influence on microstructural changes in the weld metal. We examined the kinetics of austenite formation by the application of simulated microstructures. Special attention was dedicated to the thermal welding cycle's influence on the formation of microstructures with very low toughness, which could be potential triggers of brittle fracture. The simulated microstructures were prepared by the application of several simulated thermal cycles with different peak temperatures, on samples of real single-pass weld metal.

The results of this research show that martensite-austenite constituents form in the overcritical temperature regions (over 950°C), too. The dissolution of carbides (particularly cementite) occurs at temperatures much higher than their expected solubility temperature, particularly over a short heating time. The nucleation rate of austenite in ferrite is not very rapid, in spite of the great amount of interfacial area on which nucleation can occur. The surface energies associated with austenite, ferrite, and carbide are not favorable for nucleation. Nucleation occurred at high angle boundaries where the surface energies are more favorable. The rate of austenite formation is controlled by the rate of growth of the austenite grains. The kinetics of austenite transformation in the weld metal are slower compared to the kinetics of austenite transformation in the heat affected zone. The weld metal is very stable and less sensitive to the thermal influence of the subsequent weld passes. The simulation of kinetics of austenite transformation in the weld metal enables the determination optimal of welding parameters, particularly the cooling rate from 800°C to 500°C.