Effect of an in-plane magnetic field on the velocity of a domain wall in a two-layered uniaxial magnetic film

The motion of an isolated domain wall in a two-layered uniaxial magnetic film has been investigated by solving Slonczewski equations by the progonka method with allowance for the demagnetizing fields of the layers. Perpendicular to the plane of the domain wall, there was applied an in-plane external magnetic field, whose intensity was varied. Static configurations of a twisted domain wall have been calculated. In the dependence of the domain-wall velocity on the magnetic field applied along the normal to the film plane, additional maxima have been revealed in the range of middle fields. The dependences of the position of the domain wall and of the phase angle on the time and the coordinate along the normal to the film plane have been calculated.     

Stress Response Is the Main Trigger of Sporadic Amyloidoses

Amyloidoses are a group of diseases associated with the formation of pathological protein fibrils with cross-β structures. Approximately 5–10% of the cases of these diseases are determined by amyloidogenic mutations, as well as by transmission of infectious amyloids (prions) between organisms. The most common group of so-called sporadic amyloidoses is associated with abnormal aggregation of wild-type proteins. Some sporadic amyloidoses are known to be induced only against the background of certain pathologies, but in some cases the cause of amyloidosis is unclear. It is assumed that these diseases often occur by accident. Here we present facts and hypotheses about the association of sporadic amyloidoses with vascular pathologies, trauma, oxidative stress, cancer, metabolic diseases, chronic infections and COVID-19. Generalization of current data shows that all sporadic amyloidoses can be regarded as a secondary event occurring against the background of diseases provoking a cellular stress response. Various factors causing the stress response provoke protein overproduction, a local increase in the concentration or modifications, which contributes to amyloidogenesis. Progress in the treatment of vascular, metabolic and infectious diseases, as well as cancers, should lead to a significant reduction in the risk of sporadic amyloidoses.     

Improving the Reliability of Interference Measurements by using Several Wavelengths

Methods are proposed to improve the reliability of interference measurements of surface nanotopography with sharp height gradients that lead to ambiguity in determining the phase of interference signals. The effect of the total measurement error on the range of multiwavelength measurements is considered. The results of field experiments demonstrating an increase in the range of measurements of nanotopography by the proposed methods in comparison with single-wavelength measurements are given.     

Photoluminescence of i-GaxIn1 ? xAs/n-GaAs heterostructures containing a random InAs quantum dot array

i-Ga _x In_{1 − x} As/n-GaAs heterostructures containing InAs quantum dots have been grown by ion beam deposition and their photoluminescence has been studied. The photoluminescence spectrum of the heterostructures contains three characteristic peaks. The peak at 1.1 eV has a large width and is due to the array of InAs quantum dots of different sizes, randomly arranged on the surface of the i-Ga _x In_{1 − x} As layer. From the position of another peak (hν = 0.94 eV), we have evaluated the composition of the Ga _x In_{1 − x} As solid solution: x = 0.64. The third photoluminescence peak corresponds to the intrinsic absorption edge of the n-GaAs substrate. The key features of luminescence photoexcitation in the heterostructures are discussed. We show that the Ga_0.64In_0.36As quantum well may accumulate not only photogenerated electrons but also electrons that come from a thin interfacial n-GaAs layer through ballistic transport.