Experimental study of intrinsic multiple Andreev reflections effect in GdO(F)FeAs superconductor array junctions

We report the first observation of the intrinsic multiple Andreev reflections effect (IMARE) in S-n-S-...-S-arrays (S = superconductor, n = normal metal) formed by "break-junction" technique in GdO(F)FeAs superconductor (Tc = 48 - 53 K). We show that superconducting gap peculiarities at dI/dV-spectra sharpen dramatically in the arrays as compared with that in the single-contact spectra; this enables to improve significantly accuracy of the bulk superconducting parameters determination. Using IMARE, we determined the large and the small gap values \Delta_L = 11 +- 1.1 meV and \Delta_S = 2.6 +- 0.4 meV. The BCS-ratio 2\Delta_L/kTc^{local} = 5.0 - 5.9 > 3.52 (Tc^{local} is the contact area critical temperature) evidences for a strong electron-boson coupling. The results obtained agree well with our previous data by Andreev spectroscopy for single SnS-contacts.Comment: 6 pages, 6 figure

Circulating free DNA in hypertensive patients with high cardiovascular risk

Aim. To evaluate the level of circulating free nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) in hypertensive patients with high cardiovascular risk.Material and methods. The study included 70 patients, of which 51 were patients with hypertension (HTN) and 19 were healthy. The study of the level of circulating free nDNA and mtDNA was carried out using quantitative polymerase chain reaction (PCR). Additionally, demographic data, comorbidities, risk factors, heredity, results of complete blood count and biochemical blood tests, electrocardiography and echocardiography were analyzed.Results. The level of nDNA in HN patients was significantly higher than in healthy patients: Me (LQ; UQ) — 227 (110; 370) copies/mL and 88 (62; 116) copies/ml, respectively (p<0,0001). In hypertensive patients with a very high cardiovascular risk, the level of nDNA and mtDNA was significantly higher compared to healthy participants: 294 (154; 489) copies/ml versus 88 (62; 116) copies/ml, p<0,0001; 56731 (42531; 129375) copies/mL versus 35156 (18325; 54956) copies/mL, p=0,015.Conclusion. The level of circulating free DNA in hypertensive patients with very high cardiovascular risk is significantly increased, and therefore this parameter can be a cardiovascular risk marker