Publications by authors named "A A Zakharchenko"

Based on analytical description of isotope production by bremsstrahlung (X-ray) radiation, an algorithm is proposed for calculating the optimal dimensions of a cylindrical target of given mass positioned at a given distance from a bremsstrahlung converter to ensure the maximum yield of the isotope product. The expressions are derived for the total activity and its distribution along the target axis. A technique of γ-spectrometric measuring the activity of a thick production target is proposed.

View Article and Find Full Text PDF

Based on a developed analytical model, a method is proposed for measuring the photonuclear cross section averaged over bremsstrahlung flux without application of additional target-monitor of photon flux. The method involves the use of a thin isotopic target, that completely overlaps the photon beam (a photonuclear converter), as well as an algorithm for processing the data on the yield of a reaction under study in such a target. The novel technique was validated on the reactions Mo(γ,n)Mo and Ni(γ,n)Ni in the range of photon end-point energy of 40.

View Article and Find Full Text PDF

An analytical method is used to describe isotope production at an electron accelerator. The key characteristics that determine the total target activity and its distribution have been established. The expressions for the reaction yield depend explicitly on the irradiation regime and parameters of the giant dipole resonance.

View Article and Find Full Text PDF

Bioprosthetic heart valves (BHV), made from glutaraldehyde-fixed xenografts, are widely used for surgical and transcatheter valve interventions but suffer from limited durability due to structural valve degeneration (SVD). We focused on metabolic syndrome (MetS), a risk factor for SVD and a highly prevalent phenotype in patients affected by valvular heart disease with a well-recognized cluster of comorbidities. Multicenter patient data (N = 251) revealed that patients with MetS were at significantly higher risk of accelerated SVD and required BHV replacement sooner.

View Article and Find Full Text PDF

Bioprosthetic heart valves (BHV) fabricated from heterograft tissue, such as glutaraldehyde pretreated bovine pericardium (BP), are the most frequently used heart valve replacements. BHV durability is limited by structural valve degeneration (SVD), mechanistically associated with calcification, advanced glycation end products (AGE), and serum protein infiltration. We investigated the hypothesis that anti-AGE agents, Aminoguanidine, Pyridoxamine [PYR], and N-Acetylcysteine could mitigate AGE-serum protein SVD mechanisms in vitro and in vivo, and that these agents could mitigate calcification or demonstrate anti-calcification interactions with BP pretreatment with ethanol.

View Article and Find Full Text PDF