Optical absorption of single-layer hexagonal boron nitride in the ultraviolet

In this paper we theoretically describe the absorption of hexagonal boron nitride (hBN) single layer. We develop the necessary formalism and present an efficient method for solving the Wannier equation for excitons. We give predictions for the absorption of hBN on quartz and on graphite. We compare our predictions with recently published results (Elias et al 2019 Nat. Commun. 10 2639) for a monolayer of hBN on graphite. The spontaneous radiative lifetime of excitons in hBN is also computed. We argue that the optical properties of hBN in the ultraviolet are very useful for the study of peptides and other biomolecules.The authors would like to thank André Chaves and Bruno Amorim for reading the manuscript, making suggestions, and for discussions on the topic of the paper. NMRP acknowledges support from the European Commission through the project 'Graphene-Driven Revolutions in ICT and Beyond' (Ref. No. 785219), and the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Financing UID/FIS/04650/2019. In addition, NMRP acknowledges COMPETE2020, PORTUGAL2020, FEDER and the Portuguese Foundation for Science and Technology (FCT) through projects PTDC/FIS- NAN/3668/2013 and POCI-01-0145-FEDER-028114, and POCI-01-0145-FEDER-029265 and PTDC/NAN-OPT/29265/2017, the authors also acknowledge the funding of Fundação da Ciência e Tecnologia, of COMPETE 2020 program in the FEDER component (European Union), through the project POCI-01-0145-FEDER-02888

Zero-energy vortices in Dirac materials

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record In this brief review, we survey the problem of electrostatic confinement of massless Dirac particles, via a number of exactly solvable one- and two-body models. By considering bound states at zero energy, we present a route to obtain truly discrete states of massless Dirac particles in scalar potentials, circumventing the celebrated Klein tunnelling phenomenon. We also show how the coupling of two ultrarelativistic particles can arise, and discuss its implications for cutting-edge experiments with two-dimensional Dirac materials. Finally, we report an analytic solution of the two-body Dirac-Kepler problem, which may be envisaged to bring about a deeper understanding of critical charge and atomic collapse in mesoscopic Dirac systems.European Union Horizon 202

Non-ST-segment elevation acute coronary syndrome in elderly patients and long-livers. Features of treatment. Literature review and case report

Despite the growing population of elderly people and long-livers every year, the treatment of acute coronary syndrome in these groups is not fully developed and is not regulated in clinical guidelines due to the lack of large randomized clinical trials. The article presents a literature review covering the following issues arising during clinical decision-making in the treatment of non-ST-segment elevation acute coronary syndrome in this group of patients: selection of invasive treatment strategy, scope of myocardial revascularization, appointment of dual antiplatelet therapy taking into account the bleeding risk, decreased renal function and senile asthenia. In addition, a case report of successful treatment of a 101-year-old female patient with non-ST-segment elevation myocardial infarction, who underwent percutaneous coronary intervention with stenting of infarct-related artery, was presented

Dielectric disorder in two-dimensional materials

Understanding and controlling disorder is key to nanotechnology and materials science. Traditionally, disorder is attributed to local fluctuations of inherent material properties such as chemical and structural composition, doping or strain. Here, we present a fundamentally new source of disorder in nanoscale systems that is based entirely on the local changes of the Coulomb interaction due to fluctuations of the external dielectric environment. Using two-dimensional semiconductors as prototypes, we experimentally monitor dielectric disorder by probing the statistics and correlations of the exciton resonances, and theoretically analyse the influence of external screening and phonon scattering. Even moderate fluctuations of the dielectric environment are shown to induce large variations of the bandgap and exciton binding energies up to the 100 meV range, often making it a dominant source of inhomogeneities. As a consequence, dielectric disorder has strong implications for both the optical and transport properties of nanoscale materials and their heterostructures

Use of glycoprotein IIb/IIIa inhibitors in myocardial infarction in the Russian Federation, according to the Russian Registry of Acute Myocardial Infarction REGION-IM

Aim. To analyze the frequency, indications, and outcomes of using glycoprotein IIb/IIIa inhibitors in patients with acute myocardial infarction (AMI) in Russia based on data from a multicenter registry.Material and methods. This work is part of the REGION-MI (Russian Registry of Acute Myocardial Infarction) multicenter retrospective-prospective observational study, which included patients admitted to hospitals in 45 regions of Russia with a diagnosis of AMI from 2020 to 2023. The decision to prescribe glycoprotein IIb/IIIa inhibitors was made by physicians. The observation period was 12 months, the following outcomes were recorded: cardiovascular events (relapse/repeated AMI, stent thrombosis, revascularisation), hemorrhagic complications, and in-hospital and all-cause mortality during the entire observation period. The study is conducted on the "Quinta" platform. Statistical data processing was performed using IBM SPSS Statistics ver.24.Results. A total of 10,884 patients were included in the registry, glycoprotein IIb/IIIa inhibitors were prescribed to 114 patients (1%), all of whom underwent percutaneous coronary intervention (PCI), while among patients with non-ST elevation myocardial infarction, the frequency of IIb/IIIa inhibitors was 0.5%, among ST-segment elevation myocardial infarction patients — 1.3%. Eptifibatide was used most often (67.5%), tirofiban was prescribed in 28.9% of cases, abciximab — 2.6%, framon — 0.9%. The most common indication for prescribing drugs were complications of PCI, in particular — distal embolism. There was a higher incidence of cardiogenic shock and multivessel revascularization in the glycoprotein IIb/IIIa inhibitor group. In-hospital mortality and adverse events within 180 days (death, cardiovascular events) did not differ between patients who did and did not receive glycoprotein IIb/IIIa inhibitors. The use of glycoprotein IIb/IIIa inhibitors in this study was associated with an increased risk of all in-hospital bleeding (odds ratio 9.656, confidence interval 2.859-3,894, p <0.001). Other predictors of in-hospital bleeding were: prescription of glycoprotein IIb/IIIa inhibitors, chronic kidney disease with glomerular filtration rate <60 ml/min/1.73 m2, body weight less than 60 kg.Conclusion. We observed a very low frequency of glycoprotein IIb/IIIa inhibitors usage in Russia, while these drugs are used mainly for complications of PCI in the group of patients with the highest risk — with cardiogenic shock, multivessel revascularisation, and complications of the procedure, which can have impact on the outcomes. Further research is needed to develop an optimal protocol for glycoprotein IIb/IIIa inhibitors administration in AMI