Large-Scale Statistical Analysis of Defect Emission in hBN: Revealing Spectral Families and Influence of Flakes Morphology

Quantum emitters in two-dimensional layered hexagonal boron nitride are quickly emerging as a highly promising platform for next-generation quantum technologies. However, precise identification and control of defects are key parameters to achieve the next step in their development. We conducted a comprehensive study by analyzing over 10,000 photoluminescence emission lines, revealing 11 distinct defect families within the 1.6 to 2.2 eV energy range. This challenges hypotheses of a random energy distribution. We also reported averaged defect parameters, including emission linewidths, spatial density, phonon side bands, and the Debye-Waller factors. These findings provide valuable insights to decipher the microscopic origin of emitters in hBN hosts. We also explored the influence of hBN host morphology on defect family formation, demonstrating its crucial impact. By tuning flake size and arrangement we achieve selective control of defect types while maintaining high spatial density. This offers a scalable approach to defect emission control, diverging from costly engineering methods. It highlights the importance of investigating flake morphological control to gain deeper insights into the origins of defects and to expand the spectral tailoring capabilities of defects in hBN

Symmetry-dependent dielectric screening of optical phonons in monolayer graphene

Quantised lattice vibrations (i.e., phonons) in solids are robust and unambiguous fingerprints of crystal structures and of their symmetry properties. In metals and semimetals, strong electron-phonon coupling may lead to so-called Kohn anomalies in the phonon dispersion, providing an image of the Fermi surface in a non-electronic observable. Kohn anomalies become prominent in low-dimensional systems, in particular in graphene, where they appear as sharp kinks in the in-plane optical phonon branches. However, in spite of intense research efforts on electron-phonon coupling in graphene and related van der Waals heterostructures, little is known regarding the links between the symmetry properties of optical phonons at and near Kohn anomalies and their sensitivity towards the local environment. Here, using inelastic light scattering (Raman) spectroscopy, we investigate a set of custom-designed graphene-based van der Waals heterostructures, wherein dielectric screening is finely controlled at the atomic layer level. We demonstrate experimentally and explain theoretically that, depending exclusively on their symmetry properties, the two main Raman modes of graphene react differently to the surrounding environment. While the Raman-active near-zone-edge optical phonons in graphene undergo changes in their frequencies due to the neighboring dielectric environment, the in-plane, zone-centre optical phonons are symmetry-protected from the influence of the latter. These results shed new light on the unique electron-phonon coupling properties in graphene and related systems and provide invaluable guidelines to characterise dielectric screening in van der Waals heterostructures and moir\'e superlattices.Comment: 22 pages, main manuscript with 3 figures, appendix with 5 figures, supplemental material with 6 figure

Long-term renal outcome in children with OCRL mutations: retrospective analysis of a large international cohort

BACKGROUND: Lowe syndrome (LS) and Dent-2 disease (DD2) are disorders associated with mutations in the OCRL gene and characterized by progressive chronic kidney disease (CKD). Here, we aimed to investigate the long-term renal outcome and identify potential determinants of CKD and its progression in children with these tubulopathies. METHODS: Retrospective analyses were conducted of clinical and genetic data in a cohort of 106 boys (LS: 88 and DD2: 18). For genotype-phenotype analysis, we grouped mutations according to their type and localization. To investigate progression of CKD we used survival analysis by Kaplan-Meier method using stage 3 CKD as the end-point. RESULTS: Median estimated glomerular filtration rate (eGFR) was lower in the LS group compared with DD2 (58.8 versus 87.4 mL/min/1.73 m(2), P < 0.01). CKD stage II-V was found in 82% of patients, of these 58% and 28% had moderate-to-severe CKD in LS and DD2, respectively. Three patients (3%), all with LS, developed stage 5 of CKD. Survival analysis showed that LS was also associated with a faster CKD progression than DD2 (P < 0.01). On multivariate analysis, eGFR was dependent only on age (b = -0.46, P < 0.001). Localization, but not type of mutations, tended to correlate with eGFR. There was also no significant association between presence of nephrocalcinosis, hypercalciuria, proteinuria and number of adverse clinical events and CKD. CONCLUSIONS: CKD is commonly found in children with OCRL mutations. CKD progression was strongly related to the underlying diagnosis but did not associate with clinical parameters, such as nephrocalcinosis or proteinuria

Investigations and modernizations of buckets of surface mining machines

Przedstawiono wyniki prac eksperymentalnych i projektowych oraz analiz numerycznych zmierzających do optymalizacji kosztów eksploatacji czerpaków stosowanych w Kopalni Węgla Brunatnego Turów. Zaprezentowano kompletne podejście do procesu projektowania i optymalizacji uwzględniające wyniki badań w rzeczywistych warunkach urabiania i wykorzystujące najnowocześniejsze narzędzia numeryczne do realizacji procesu konstruowania tego typu obiektów. Efektem prac są dwa projekty czerpaków z zębami wymiennymi i stałymi, które w znaczący sposób poprawią wskaźniki techniczno-eksploatacyjne i przełożą się na realne oszczędności uzyskiwane przez użytkowników.Results of experimental tests, design work and numerical analyses aimed to optimize the operating costs of buckets used in the Turow Surface Mine. In the presented approach of designing and optimization, results of tests in real conditions of mining are taken into account. Also modern numerical tools support the process of designing such facilities. Results of the presented work are two buckets with quick replaceable and permanent teeth, which significantly improve the technical and operational indicators and enable real savings achieved by the users