Efficiency of Electron-Positron Pair Productionby Neutrino Flux from Accretion Disk of a Kerr Black Hole

Dominant processes of neutrino production and neutrino-induced \ep-pair production are examined in the model of a disk hyper-accreting onto a Kerr black hole. The efficiency of plasma production by a neutrino flux from the disk, obtained for the both cases of presence and absence of a magnetic field, is found to be no more than several tenths of percent and, therefore, not enough for the origin of cosmological gamma-ray bursts.Comment: 8 pages, 1 figur

Immunophenotype and metabolism are linked in peripheral blood neutrophils from patients with kidney cancer

The aim of the present study was to analyze the relationships between expression of activation and adhesion receptors on peripheral blood neutrophils, and intracellular activity of some neutrophil enzymes in patients with kidney cancer (KC). Patients and methods: the KC patients (n = 72) (T3N0M0, clear-cell type) were examined prior to surgical treatment at the Krasnoyarsk Regional Oncology Center. The diagnosis was verified histologically for all KC patients. The phenotype of blood neutrophils was studied using flow cytometry. The surface receptor expression levels of the neutrophils were evaluated by mean fluorescence intensity. NAD and NADP-dependent dehydrogenases activities in purified peripheral blood neutrophils were measured by bioluminescent method. Results: we have found that the phenotypic alterations in circulating KC patients’ neutrophils appeared along with inhibition of main intracellular metabolic processes and were closely linked with them. The features of the phenotypic imbalance in the neutrophils from KC patients were associated with a decrease in blood cells expressing adhesive (CD11b and CD62L) and functional (CD64 and HLA-DR) receptors. Moreover, the patient’s neutrophils expressed CD11b, CD16 and HLA-DR on their cell surface more intensively, than neutrophilic leukocytes from control group. These phenotypic changes in KC patients’ blood neutrophils occurred in parallel with pronounced decrease in immature cells numbers. The metabolic changes of neutrophil cytoplasmic compartment in KC patients were determined by a decrease in Glu6PDH activity (a key and initializing enzyme of the pentose phosphate cycle) and NADH-LDH (anaerobic glycolysis). Mitochondrial metabolism in neutrophils of KC patients was characterized by multidirectional changes in the activity of NAD- and NADP-dependent glutamate dehydrogenases (decreased activity of NAD-dependent and increased activity of NADP-dependent) and a decrease in NADH-MDH activity. The established features in mitochondrial enzymes activities suggest some disturbances of NAD-dependent processes that could lead to down-regulation of aerobic energy processes. We guess that the decreased activity of plastic and energy processes in blood neutrophils of KC patients could affect the receptor expression levels. By means of correlation analysis, we have found that the relationships in KC patients were determined by negative effects of NADHGDH and NADH-LDH activities upon expression of activation and adhesion receptors in blood neutrophils. Of these enzymes, only glutathione reductase activity in neutrophils from KC patients was positively linked with the CD23 and HLA-DR expression. Thus, an increase in activity of energy processes (e.g., coupling the tricarboxylic acid cycle to amino acid metabolism) in blood neutrophils from the patients with kidney cancer could stimulate expression levels of activation and adhesion receptors and potentially increase antitumor activity of neutrophils

Semiclassical approach to the decay of protons in circular motion under the influence of gravitational fields

We investigate the possible decay of protons in geodesic circular motion around neutral compact objects. Weak and strong decay rates and the associated emitted powers are calculated using a semi-classical approach. Our results are discussed with respect to distinct ones in the literature, which consider the decay of accelerated protons in electromagnetic fields. A number of consistency checks are presented along the paper.Comment: To appear in Physical Review

Disadvantages of distance learning for students and teachers

The main difficulties faced by students and teachers during the transition to forced distance learning during quarantine are considered and ways to solve some of them are indicated

FUNCTIONAL ACTIVITY OF NEUTROPHILS AND HEMOSTASIS PATTERN IN PATIENTS WITH ACUTE DESTRUCTIVE PANCREATITIS

The aim of present study was to investigate relationships between indicators of functional activity of neutrophilic granulocytes, and hemostasis parameters in patients with acute destructive pancreatitis (ADP). The study included thirty-three patients with ADP. 35 healthy persons were examined as a control group. The phagocytosis level in neutrophils was determined by flow cytometry using FITC-labeled staphylococcal protein A. We have calculated the percentage of fluorescent neutrophils as phagocytic index, and average cell fluorescence assumed phagocytic number. The intensity of respiratory burst observed in neutrophil samples was evaluated using chemiluminescence assay. All the persons under study were also tested for blood coagulation and vascular-platelet hemostasis. It was found that the ADP patients with decreased number of phagocytic neutrophils in the blood showed a decrease in respiratory burst intensity in the neutrophils. Moreover, spontaneous and induced synthesis of the primary reactive oxygen species (ROS) in neutrophils of ADP patients proceeded faster than in healthy people, but its intensity was much lower. The maximal level of spontaneous and induced synthesis of secondary ROS in neutrophils of patients was significantly higher than in healthy individuals, but its rapid may be generally characterized by insufficient respiratory burst in these patients. A reduced neutrophil phagocytic activity and kinetic characteristics of primary and secondary ROS synthesis may be attributed to the effects produced by pancreatic enzymes entering blood flow which may alter functional activity of the blood neutrophils. Concerning hemostasis in patients with ADP, some disturbances were found only in the coagulation link which seem to depend on increase in fibrinogen, soluble fibrin monomer complexes and D-dimer in blood plasma, along with reduced antithrombin III levels. Such a change in blood coagulation indexes is typical to inflammatory processes and presumes activation of the coagulation cascade and higher risk of septic complications. In patients with ADP, we have found a significantly increased number of correlations between indicators of functional activity of neutrophils and hemostasis parameters. This analysis revealed a relationship by the patients with ADP reflect some unidirectional changes in functional activity of neutrophils (as phagocytosis and respiratory burst), and blood coagulation parameters (as blood clotting and vascular/ platelet links). The changes in functional activity of neutrophils and the state of hemostasis in the ADP patients, as well as correlations between their alterations are omvolved into the pathogenesis of this disorder, and determine potential mechanisms for evolving complications