Magnetization reversal of ferromagnetic nanodisc placed above a superconductor

Using numerical simulation we have studied a magnetization distribution and a process of magnetization reversal in nanoscale magnets placed above a superconductor plane. In order to consider an influence of superconductor on magnetization distribution in the nanomagnet we have used London approximation. We have found that for usual values of London penetration depth the ground state magnetization is mostly unchanged. But at the same time the fields of vortex nucleation and annihilation change significantly: the interval where vortex is stable enlarges on 100-200 Oe for the particle above the superconductor. Such fields are experimentally observable so there is a possibility of some practical applications of this effect.Comment: 8 pages, 9 figure

A New Chapter in the Treatment of Patients with Heart Failure. The Role of Sodium-Glucose Co-transporter Type 2 Inhibitors

Heart failure (HF) remains one of the major social and medical public health problems worldwide. Despite new advances in the treatment of patients with HF, the prognosis is still poor. According to the European Cardiology Society guidelines for the diagnosis and treatment of acute and chronic heart failure (CHF) 2021, a new class of drugs related to hypoglycemic has been confirmed to be effective in influencing the survival of patients with heart failure with low ejection fraction (HFpEF), regardless of the presence of disorders of carbohydrate metabolism. We are talking about inhibitors of the sodium-glucose co-transporter type 2 (iSGLT-2) or gliflozins. The article presents the results of the latest large clinical trials on the effective use of SGLT-2 in patients with HF, not only with low, but also with intact ejection fraction (HFpEF), for which there is no evidence base at the present stage. The review article presents the results of experimental studies that explored the potential mechanisms of action of gliflozins with an emphasis on new ones that are of fundamental importance for patients with heart failure, and also describes controversial and little-studied issues. Currently, there is no therapy that improves outcomes in patients with acute heart failure. The article presents the results of small analyzes of the use of iSGLT-2 in this category of patients, which are the basis for the hypothesis of their potentially effective and safe use in the case of acute decompensation of CHF, however, the role of gliflozins in this category of patients requires further in-depth study

Interacting circular nanomagnets

Regular 2D rectangular lattices of permalloy nanoparticles (40 nm in diameter) were prepared by the method of the electron lithography. The magnetization curves were studied by Hall magnetometry with the compensation technique for different external field orientations at 4.2K and 77K. The shape of hysteresis curves indicates that there is magnetostatic interaction between the particles. The main peculiarity is the existence of remanent magnetization perpendicular to easy plain. By numerical simulation it is shown, that the character of the magnetization reversal is a result of the interplay of the interparticle interaction and the magnetization distribution within the particles (vortex or uniform).Comment: 16 pages, 8 figure

A hysteresis model with dipole interaction: one more devil-staircase

Magnetic properties of 2D systems of magnetic nanoobjects (2D regular lattices of the magnetic nanoparticles or magnetic nanostripes) are considered. The analytical calculation of the hysteresis curve of the system with interaction between nanoobjects is provided. It is shown that during the magnetization reversal system passes through a number of metastable states. The kinetic problem of the magnetization reversal was solved for three models. The following results have been obtained. 1) For 1D system (T=0) with the long-range interaction with the energy proportional to $r^{-p}$, the staircase-like shape of the magnetization curve has self-similar character. The nature of the steps is determined by interplay of the interparticle interaction and coercivity of the single nanoparticle. 2) The influence of the thermal fluctuations on the kinetic process was examined in the framework of the nearest-neighbor interaction model. The thermal fluctuations lead to the additional splitting of the steps on the magnetization curve. 3) The magnetization curve for system with interaction and coercivity dispersion was calculated in mean field approximation. The simple method to experimentally distinguish the influence of interaction and coercivity dispersion on the magnetization curve is suggested.Comment: 22 pages, 8 figure

Magnetization curves for two-dimensional rectangular lattices of permalloy nanoparticles: experimental investigation and numerical simulation

Abstract This work is concerned with the behaviour of a regular 2D rectangular lattice of Ni 3 Fe nanoparticles, determined by the dipole interaction between them. The samples under study, prepared by electron-beam lithography, consisted of about 10 5 particles approximately 50 nm in size. The magnetization curves were studied by Hall magnetometry for different external magnetic field orientations at 4.2 K and 77 K. The results indicate a collective behaviour of the system. The magnetization curves depend on the external magnetic field direction and temperature; the system exhibits multistability. A model system of interacting 3D magnetic dipoles forming a rectangular lattice was numerically simulated by solving a system of stochastic Landau-Lifshitz equations. The multistability of the system and steps in the magnetization curves were obtained. It is shown analytically that the shape of the magnetization curves depends on the character of the interaction in the system

Role of glycemic control in elective percutaneous coronary interventions in patients with type 2 diabetes

Aim. To assess the association of glycemic control (achievement of an individual target glycated hemoglobin level) with the outcomes of elective percutaneous coronary interventions in patients with type 2 diabetes (T2D).Material and methods. This cohort observational study included 74 patients with a median age of 61 (57; 64) years. There were 49% of men with a previously established T2D, who had indications for elective primary percutaneous coronary intervention (PCI) for stable coronary artery disease. At inclusion in the study and after 1 month, the concentration of fasting blood glucose, glycated hemoglobin (HbA1c), fructosamine, and serum creatinine were determined. Plasma glucose levels were determined using the hexokinase method. HbA1c level was determined by immunoturbidimetry on a Konelab 30i chemistry analyzer. The concentration of fructosamine was determined by the kinetic colorimetric assay on a Konelab 30i chemistry analyzer. Statistical processing was carried out using the Statistica 10.0 program from StatSoft, Inc. (USA).Results. At the time of enrollment, 31% of participants had not achieved the target glycated hemoglobin level against the background of nonoptimal hypoglycemic therapy in most cases. A total of 18 (25%) following adverse cardiovascular events were registered within 12 months after PCI: 11 (15%) patients developed acute coronary syndrome; among them, 6 (8%) patients had stent restenosis according to coronary angiography, 4 (6%) patients — progression of atherosclerosis, which required repeated PCI with stenting of another vessel, 2 (3%) patients — cerebrovascular accident, and 3 (4%) patients were hospitalized due to de compensated heart failure. According to multivariate logistic regression, only the HbA1c level was a predictor of adverse outcomes during the year after PCI — a 1% increase in HbA1c level increased the risk of adverse outcomes by 1,79 times (odds ratio, 1,79, 95% confidence interval, 1,06-3,02, p=0,028). Poor glycemic control 1 month before PCI increased the risk of cardiovascular events by 4,04 times over the next year, while non-target HbA1c level immediately before PCI increased the risk of adverse outcomes by 4,7 times, and 5 months after PCI, by 7,34 times.Conclusion. The significance of non-target glycated hemoglobin level for adverse outcomes during the year after elective PCI against the background of T2D was established with an increase in the negative effect as long-term (after myocardial revascularization) maintenance of poor glycemic control

International longitudinal registry of patients with atrial fibrillation and treated with rivaroxaban: RIVaroxaban Evaluation in Real life setting (RIVER)

Background Real-world data on non-vitamin K oral anticoagulants (NOACs) are essential in determining whether evidence from randomised controlled clinical trials translate into meaningful clinical benefits for patients in everyday practice. RIVER (RIVaroxaban Evaluation in Real life setting) is an ongoing international, prospective registry of patients with newly diagnosed non-valvular atrial fibrillation (NVAF) and at least one investigator-determined risk factor for stroke who received rivaroxaban as an initial treatment for the prevention of thromboembolic stroke. The aim of this paper is to describe the design of the RIVER registry and baseline characteristics of patients with newly diagnosed NVAF who received rivaroxaban as an initial treatment. Methods and results Between January 2014 and June 2017, RIVER investigators recruited 5072 patients at 309 centres in 17 countries. The aim was to enroll consecutive patients at sites where rivaroxaban was already routinely prescribed for stroke prevention. Each patient is being followed up prospectively for a minimum of 2-years. The registry will capture data on the rate and nature of all thromboembolic events (stroke / systemic embolism), bleeding complications, all-cause mortality and other major cardiovascular events as they occur. Data quality is assured through a combination of remote electronic monitoring and onsite monitoring (including source data verification in 10% of cases). Patients were mostly enrolled by cardiologists (n = 3776, 74.6%), by internal medicine specialists 14.2% (n = 718) and by primary care/general practice physicians 8.2% (n = 417). The mean (SD) age of the population was 69.5 (11.0) years, 44.3% were women. Mean (SD) CHADS2 score was 1.9 (1.2) and CHA2DS2-VASc scores was 3.2 (1.6). Almost all patients (98.5%) were prescribed with once daily dose of rivaroxaban, most commonly 20 mg (76.5%) and 15 mg (20.0%) as their initial treatment; 17.9% of patients received concomitant antiplatelet therapy. Most patients enrolled in RIVER met the recommended threshold for AC therapy (86.6% for 2012 ESC Guidelines, and 79.8% of patients according to 2016 ESC Guidelines). Conclusions The RIVER prospective registry will expand our knowledge of how rivaroxaban is prescribed in everyday practice and whether evidence from clinical trials can be translated to the broader cross-section of patients in the real world