Innovative material based on wood waste for application in special purpose vehicles

The article presents innovative composite wood material DS-1 with a powder binding, which is used in special purpose vehicles. Vehicles for transporting radioactive waste for its recycling and disposal, and radiodiagnostics mobile complexes intended for conducting massive X-ray have been considered. The composition of material DS-1 has been revealed, experiments have been listed and a table with physical and mechanical properties has been given. Relying on experimental analysis data it can be concluded that implementation of innovative composite material DS-1 with a powder binder using barium sulphate helps solve the problem of lead replacement with lighter environmentally friendly material and contributes to complex use of wood raw materials Using a low-toxic binder in the material obtained makes its production innocuous and environmentally friendly and and solves a number of economic and energy-saving problems. © 2019 Published under licence by IOP Publishing Ltd

Thermal drag revisited: Boltzmann versus Kubo

The effect of mutual drag between phonons and spin excitations on the thermal conductivity of a quantum spin system is discussed. We derive general expression for the drag component of the thermal current using both Boltzmann equation approach and Kubo linear-response formalism to leading order in the spin-phonon coupling. We demonstrate that aside from higher-order corrections which appear in the Kubo formalism both approaches yield identical results for the drag thermal conductivity. We discuss the range of applicability of our result and provide a generalization of our consideration to the cases of fermionic excitations and to anomalous forms of boson-phonon coupling. Several asymptotic regimes of our findings relevant to realistic situations are highlighted.Comment: 14 pages, 3 figures, published version, extended discussio

Long Range Dynamics Related to Magnetic Impurity in the 2D Heisenberg Antiferromagnet

We consider a magnetic impurity in the two-dimensional Heisenberg antifferomagnet with long range antiferromagnetic order. At low temperature the impurity magnetic susceptibility has a Curie term ($\propto 1/T$) and a logarithmic correction ($\propto \ln(T)$). We calculate the correction and derive related Ward identity for the impurity-spin-wave vertex.Comment: 5 pages, 6 figure

Hole-hole superconducting pairing in the t-J model induced by spin-wave exchange

We study numerically the hole pairing induced by spin-wave exchange. The contact hole-hole interaction is taken into account as well. It is assumed that antiferromagnetic order is preserved at all scales relevant to pairing. The strongest pairing is obtained for the d-wave symmetry of the gap. Dependence of the value of the gap on hole concentration and temperature is presented. For the critical temperature we obtain Tc about 100 K at the hole concentration delta = 0.2-0.3.Comment: replaced with a revised version to appear in PRB, 6 pages, REVTeX 3.0, figures not change

Pathogenetic and Prognostic Significance of Thrombocytopenia in Patients With Necrotizing Soft Tissue Infections

Necrotizing soft tissue infection (NSTI) is a severe surgical infection which can result in sepsis and septic shock when generalized.The aim of the study was to determine the frequency of thrombocytopenia in patients with generalized NSTI, the factors promoting its development, and its association with septic shock.Materials and Methods. We examined 129 patients with NSTI treated between 09.2015 and 12.2019 at St. George Hospital in St. Petersburg, Russia. Surgical treatment, hematological and biochemical examinations, and bacteriological analysis of blood and wound discharge were performed in each patient. The studied group included 22 patients with systemic inflammatory reaction syndrome, 63 patients with sepsis, and 44 patients with septic shock.Results. We found a decrease in platelet count in NSTI patients with septic shock as early as on the first day of the disease and its further decrease within the next 3 days, with the mean platelet volume (MPV) increasing during the same period and significantly exceeding that in patients with sepsis and systemic inflammatory response syndrome. In NSTI patients with thrombocytopenia on admission, we found a significant correlation between the platelet count and the percentage of segmented neutrophils (r=0.349; P<0.001; n=40). The maximum incidenсe of septic shock was observed in patients infected with Klebsiella pneumoniae (13 out of 19, 65%). These patients had the highest MPV but did not develop thrombocytopenia. Maximum frequency of thrombocytopenia and elevation of MPV and platelet distribution width (PDW) was found in patients with NSTI and underlying chronic viral hepatitis C. However, the relative frequency of septic shock in these patients was not increased.Conclusion. The development of septic shock in NSTI is associated with a specific platelet activation patter

Патогенетическое и прогностическое значение тромбоцитопении у пациентов с некротизирующими инфекциями мягких тканей

Necrotizing soft tissue infection (NSTI) is a severe surgical infection which can result in sepsis and septic shock when generalized.The aim of the study was to determine the frequency of thrombocytopenia in patients with generalized NSTI, the factors promoting its development, and its association with septic shock.Materials and Methods. We examined 129 patients with NSTI treated between 09.2015 and 12.2019 at St. George Hospital in St. Petersburg, Russia. Surgical treatment, hematological and biochemical examinations, and bacteriological analysis of blood and wound discharge were performed in each patient. The studied group included 22 patients with systemic inflammatory reaction syndrome, 63 patients with sepsis, and 44 patients with septic shock.Results. We found a decrease in platelet count in NSTI patients with septic shock as early as on the first day of the disease and its further decrease within the next 3 days, with the mean platelet volume (MPV) increasing during the same period and significantly exceeding that in patients with sepsis and systemic inflammatory response syndrome. In NSTI patients with thrombocytopenia on admission, we found a significant correlation between the platelet count and the percentage of segmented neutrophils (r=0.349; P<0.001; n=40). The maximum incidenсe of septic shock was observed in patients infected with Klebsiella pneumoniae (13 out of 19, 65%). These patients had the highest MPV but did not develop thrombocytopenia. Maximum frequency of thrombocytopenia and elevation of MPV and platelet distribution width (PDW) was found in patients with NSTI and underlying chronic viral hepatitis C. However, the relative frequency of septic shock in these patients was not increased.Conclusion. The development of septic shock in NSTI is associated with a specific platelet activation patternНекротизирующая инфекция мягких тканей (НИМТ) — тяжелая хирургическая инфекция, при генерализации которой часто развивается сепсис и септический шок.Цель исследования — определить частоту тромбоцитопении у больных с генерализованными формами НИМТ, факторы, способствующие ее развитию и связь с развитием септического шока.Материал и методы. Обследовали 129 больных c НИМТ, лечившихся с 09.2015 по 12.2019 гг. в больнице Св. Великомученика Георгия Санкт-Петербурга. Всем пациентам провели хирургическое лечение, лабораторное гематологическое и биохимическое обследование и бактериологическое исследование крови и отделяемого из раны. Всего больных с синдромом системной воспалительной реакции было 22, с сепсисом — 63, септическим шоком — 44 человека.Результаты. Выявили снижение количества тромбоцитов у больных НИМТ с септическим шоком уже в первые сутки заболевания и дальнейшее его снижение в течение 3-х дней, причем средний объем тромбоцитов (MPV) в эти же сроки возрастал и существенно превосходил таковой у больных с сепсисом и синдромом системной воспалительной реакции. У больных НИМТ, имевших при поступлении тромбоцитопению, выявили статистически значимую корреляцию количества тромбоцитов с долей сегментоядерных нейтрофилов (r=0,349; р<0,001; n=40). Максимальную частоту септического шока отметили у больных, инфицированных Klebsiella pneumoniaе (13 из 19, 65%). У этих больных тромбоциты имели наибольший MPV, однако тромбоцитопения не развивалась. Максимальную частоту тромбоцитопении, увеличение MPV и анизоцитоз (относительную ширину распределения тромбоцитов по объему — PDW) выявили у больных с развитием НИМТ на фоне хронического вирусного гепатита С. Однако, сравнительная частота развития септического шока у этих больных не была повышена.Заключение. Развитие септического шока при НИМТ обусловлено определенным типом активации тромбоцито

Two-hole problem in the t-J model: A canonical transformation approach

The t-J model in the spinless-fermion representation is studied. An effective Hamiltonian for the quasiparticles is derived using canonical transformation approach. It is shown that the rather simple form of the transformation generator allows to take into account effect of hole interaction with the short-range spin waves and to describe the single-hole groundstate. Obtained results are very close to ones of the self-consistent Born approximation. Further accounting for the long-range spin-wave interaction is possible on the perturbative basis. Both spin-wave exchange and an effective interaction due to minimization of the number of broken antiferromagnetic bonds are included in the effective quasiparticle interaction. Two-hole bound state problem is solved using Bethe-Salpeter equation. The only d-wave bound state is found to exist in the region of 1< (t/J) <5. Combined effect of the pairing interactions of both types is important to its formation. Discussion of the possible relation of the obtained results to the problem of superconductivity in real systems is presented.Comment: 19 pages, RevTeX, 12 postscript figure

Hole-Hole Contact Interaction in the t-J Model

Using an analytical variational approach we calculate the hole-hole contact interaction on the N\'{e}el background. Solution of the Bethe-Salpeter equation with this interaction gives bound states in $d$- and p-waves with binding energies close to those obtained by numerical methods. At $t/J \ge 2-3$ the bound state disappears. In conclusion we discuss the relation between short range and long range interactions and analogy with the problem of pion condensation in nuclear matter.Comment: 11 pp. (LATEX), 7 figures (PostScript) appended, report N