Resonant and Non-Resonant Impurity States Related to GaAs/AlGaAs Quantum Well Sub-Bands.

The energy positions and wave function shapes of the ground and excited states of impurities, including resonance states, are studied using the expansion of the impurity wave function in basis functions. The structures under study are rectangular GaAs/AlGaAs quantum wells with four different widths. In all cases, the impurity binding energy (relative to the corresponding sub-band) has a maximum at or near the center of the quantum well, decreases as the heterointerface is approached, and apparently has a limit of 0 if the impurity moves deeper into the barrier.

Optoelectronic Properties of Shallow Donor Atom in 2D-Curved Nanostructures Under External Electric and Magnetic Fields.

Using the effective mass approximation and the finite difference method, we examined the linear, non-linear, and total optical absorption coefficients (OAC), as well as the relative refractive index coefficients (RIC) variations for an off-center shallow donor impurity in a 2D-curved electronic nanostructure subjected to external electric and magnetic fields. Our results reveal that the peak positions of the OAC and RIC are susceptible to the geometrical angles, the impurity position, and the strength of the applied electric and magnetic fields. In particular, the positions of the OAC and RIC peaks can be shifted towards blue or red by adjusting the geometric angle.

Numerical proceeding to calculate impurity states in 2D semiconductor heterostructures.

The article provides and discusses details of numerical proceeding for the expansion method to calculate energy positions and wave functions of the localized and resonant electronic states emerging in quantum well-type semiconductor nanostructures because of perturbation of confined states by the Coulomb potential of the hydrogenic impurity center. Effective mass approximation is used. Several excited both resonant and non-resonant states are calculated and classified for the case of a simple rectangular GaAs/AlGaAs quantum well.

Effects of quercetin on mineralized dental tissues: A scoping review.

Objective: This scoping review (SR) aimed to investigate the impact of quercetin on mineralized dental tissues intended to be used in preventive and restorative dentistry.

Methods: This SR was conducted following the PRISMA-ScR statement. A comprehensive search was performed across databases for articles published up to March 2024.

Cerebrovascular hemodynamics association with brain structure and function in Multiple Sclerosis.

Background: Vascular risk factors seem to contribute to disease progression in Multiple Sclerosis (MS), but the mechanistic connection between vascular risk and MS is unknown. Understanding cerebrovascular hemodynamics (CVH) in MS may help advance our understanding of the link between vascular risk and MS.

Objectives: Examine the relationship between CVH [dynamic cerebral autoregulation (dCA) and vasoreactivity (VR)] and brain structure (MRI) and function (cognition, and gait) in individuals with MS.