Investigating moiré interlayer excitons under the influence of atomic reconstructions

The moiré pattern which emerges due to a relative rotation between two monolayers of transition metal dichalcogenides (TMDs) features a long lattice period for small twist angles. The resulting band structure modulation acts as an effective potential for interlayer excitons (IXs). However, lattice reconstructions change the moiré potential which forms broader and deeper potential minima, realizing a periodic array of quantum wells for IXs. This serves as an implementation of the Bose-Hubbard (BH) model for the simulation of correlated excitonic states. Expanding on previous results [1], we describe the correlated behavior of IXs in the moiré lattice with an extended BH model taking into account non local interactions and a material realistic modelling of the dielectric screening. Considering interatomic forces, we discuss how the BH parameters and especially the excitonic wave functions are influenced by local atomic reconstructions. Furthermore, by solving the BH model with a sublattice mean-field description, we address the question in how far correlated states of moiré excitons emerge at different twist angles and integer as well as fractional lattice fillings. [1] Götting et al., Phys. Rev. B 105, 165419 (2022

Enkele determinante in Aardrykskunde-onderrig in swart skole

D.Ed. (Education)Please refer to full text to view abstrac

Biodistribution of a potential chemotherapeutic, dinuclearbisphosphinogold(I) dithiocarbamate, as determined by its 198Au radiolabelled analogue

Dinuclearbisphosphinogold(I) dithiocarbamato, BPDTC, was previously found to have antitumour activity in vitro. 198Au radiolabelled BPDTC (radiochemical yield of 70 ± 6 % and radiochemical purity of[95 %) was used to determine its in vivo biodistribution in Sprague-Dawley rats. Gamma scintigraphs were performed over a period of 48 h and final radioactivity measurements of harvested organs of the test animals after termination was performed at 2, 4 and 48 h. The study successfully showed the biodistribution of the gold complex, with the highest uptake of the compound being observed in the lungs, liver and spleenNuclear Technologies in Medicine and the Biosciences Initiative (NTeMBI), a national technology platform developed and managed by the South African Nuclear Energy Corporation (Necsa) and funded by the Department of Science and Technology. Biomed (Mintek

Evolutionary stability of altruism and envy in Tullock contests

Evolutionary stability, Contests, Conflict theory, Envy, Altruism,

Nonconventional MRI and microstructural cerebral changes in multiple sclerosis

MRI has become the most important paraclinical tool for diagnosing and monitoring patients with multiple sclerosis (MS). However, conventional MRI sequences are largely nonspecific in the pathology they reveal, and only provide a limited view of the complex morphological changes associated with MS. Nonconventional MRI techniques, such as magnetization transfer imaging (MTI), diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI) promise to complement existing techniques by revealing more-specific information on microstructural tissue changes. Past years have witnessed dramatic advances in the acquisition and analysis of such imaging data, and numerous studies have used these tools to probe tissue alterations associated with MS. Other MRI-based techniques-such as myelin-water imaging, 23 Na imaging, magnetic resonance elastography and magnetic resonance perfusion imaging-might also shed new light on disease-associated changes. This Review summarizes the rapid technical progress in the use of MRI in patients with MS, with a focus on nonconventional structural MRI. We critically discuss the present utility of nonconventional MRI in MS, and provide an outlook on future applications, including clinical practice. This information should allow appropriate selection of advanced MRI techniques, and facilitate their use in future studies of this disease