Phase transition to the state with nonzero average helicity in dense neutron matter

The possibility of the appearance of the states with a nonzero average helicity in neutron matter is studied in the model with the Skyrme effective interaction. By providing the analysis of the self-consistent equations at zero temperature, it is shown that neutron matter with the Skyrme BSk18 effective force undergoes at high densities a phase transition to the state in which the degeneracy with respect to helicity of neutrons is spontaneously removed.Comment: 4 pages, 3 figures; v2: journal versio

Spin polarized states in strongly asymmetric nuclear matter

In the framework of a Fermi liquid theory it is considered the possibility of appearance of spin polarized states in strongly asymmetric nuclear matter with Skyrme effective interaction. The zero temperature dependence of neutron and proton spin polarization parameters as functions of density is found for SLy4, SLy5 effective forces. It is shown that at some critical density it will be formed the state with the oppositely directed spins of neutrons and protons, while the state with the same direction of spins does not appear. In comparison with neutron matter, even small admixture of protons strongly decreases the threshold density of spin instability. It is clarified that protons become totally polarized within very narrow density domain while in the density profile of neutron spin polarization parameter their appear long tails near the transition density.Comment: Prepared with RevTeX4, 8p., 3 figures; to appear in PR

Anisotropic multi-gap superfluid states in nuclear matter

It is shown that under changing density or temperature a nucleon Fermi superfluid can undergo a phase transition to an anisotropic superfluid state, characterized by nonvanishing gaps in pairing channels with singlet-singlet (SS) and triplet-singlet (TS) pairing of nucleons (in spin and isospin spaces). In the SS pairing channel nucleons are paired with nonzero orbital angular momentum. Such two-gap states can arise as a result of branching from the one-gap solution of the self-consistent equations, describing SS or TS pairing of nucleons, that depends on the relationship between SS and TS coupling constants at the branching point. The density/temperature dependence of the order parameters and the critical temperature for transition to the anisotropic two-gap state are determined in a model with the SkP effective interaction. It is shown that the anisotropic SS-TS superfluid phase corresponds to a metastable state in nuclear matter.Comment: Prepared with RevTeX4, 7p., 5 fi

Competition of ferromagnetic and antiferromagnetic spin ordering in nuclear matter

In the framework of a Fermi liquid theory it is considered the possibility of ferromagnetic and antiferromagnetic phase transitions in symmetric nuclear matter with Skyrme effective interaction. The zero temperature dependence of ferromagnetic and antiferromagnetic spin polarization parameters as functions of density is found for SkM$^*$, SGII effective forces. It is shown that in the density domain, where both type of solutions of self--consistent equations exist, ferromagnetic spin state is more preferable than antiferromagnetic one.Comment: 9p., 3 figure

RETINAL VESSELS DIGITAL MORPHOMETRY IN ANALYSIS OF LASER TREATMENT RESULTS IN RETINOPATHY OF PREMATURITY

Purpose. Quantification of morphometric parameters of segments of retinal vessels of the central fundus zone, vessels of the 2nd order and peripheral vessels in the vicinity of the avascular zone to detect early signs and dynamics of stage II and III regression in retinopathy of prematurity (ROP) in different periods after laser treatment (LT).Material and methods. There were examined 50 preterm infants (100 eyes) with the type 2 (a high risk of progression) of the ROP stage II and III before and in different periods after pattern laser photocoagulation. The morphometric analysis of obtained digital images of the retina in children with ROP was performed using the retinal camera «RetCam 3» (Clarity Medisal Systems, Inc.,USA) in mode of the software «ROP-MORRNOMETRY».Results. Statistically significant differences in the diameter of retinal vessels throughout their length and the tortuosity factor of arteries in the central fundus zone in the follow-up of 1 and 2 months after laser treatment were not revealed, indicating a robust ROP regression.Conclusions. Clinical applications of data obtained in the performed study allows to optimize the postoperative monitoring of premature infants with ROP, minimizing the quantity of repeated diagnostic tests

Оценка эффективности оперативного лечения больных с хронической критической ишемией нижних конечностей в стадии трофических осложнений

Relevance. Chronic critical ischemia of the lower extremities (CCILE) in the stage of trophic complications is the final stage of diseases of the arteries of the lower extremities, leading to disability of patients and having a poor prognosis in terms of preservation of the lower extremities and mortality.Aim of study. Objective assessment of the efficacy of lower limb revascularization in trophic disorders.Material and methods. The analysis of treatment of 52 patients with stage IV CCILE (according to the classification of R. Fontaine and A.V. Pokrovsky) was carried out. Of these, 42 patients underwent three-phase scintigraphy combined with X-ray computed angiography on a hybrid apparatus. After the operation, this study was conducted in 37 patients.Results. Out of 52 patients, surgery for revascularization of the lower extremities was performed in 37 patients, 15 were not operated on. Out of 37 operated patients, improvement of blood circulation occurred in 32 (86.5%). Circulatory decompensation was observed in 5 patients (9.7%). Among non-operated patients, improvement of blood circulation occurred in 9 patients (17.3%), no effect or decompensation — in 5 (9.7%). Subjective improvement in the condition and decrease in the degree of ischemia corresponded to the improvement of microcirculation according to the data of three-phase scintigraphy.Conclusion.1. Revascularization of the lower extremities in patients with trophic disorders is an effective method of treating this pathology. Therefore, all patients with chronic ischemia threatening limb loss should be considered as candidates for revascularization.2. If the leg arteries or short occlusive or stenotic lesions of the main arteries are affected, such patients should be discussed together with specialists in endovascular surgery for endovascular treatment or joint intervention.3. Hybrid radiation method (three-phase scintigraphy and single-photon emission computed tomography, combined with X-ray computed angiography) is an objective method that reflects the state of peripheral circulation and microcirculation, and allows you to objectively assess the effectiveness of the treatment.Актуальность. Хроническая критическая ишемия нижних конечностей (ХКИНК) в стадии трофических осложнений представляет собой конечную стадию заболеваний артерий нижних конечностей, приводящую к инвалидизации больных и имеющую неблагоприятный прогноз по показателям сохранения нижних конечностей и летальности.Цель исследования. Объективная оценка эффективности реваскуляризации нижних конечностей при трофических расстройствах.Материал и методы. Проведен анализ лечения 52 больных ХКИНК IV стадии (по классификации R. Fontaine и А.В. Покровского). Из них 42 пациентам выполнена трехфазная сцинтиграфия, совмещенная с рентгеновской компьютерной ангиографией на гибридном аппарате. После операции данное исследование проведено 37 пациентам.Результаты. Из 52 пациентов операция по реваскуляризации нижних конечностей выполнена 37 пациентам, не оперированы 15. Из 37 оперированных улучшение кровообращения произошло у 32 (86,5%). Декомпенсация кровообращения отмечена у 5 пациентов (9,7%). Среди неоперированных пациентов улучшение кровообращения произошло у 9 пациентов (17,3%), отсутствие эффекта или декомпенсация — у 5 (9,7%). Субъективное улучшение состояния и снижение степени ишемии соответствовали улучшению микроциркуляции по данным трехфазной сцинтиграфии.Выводы.1. Реваскуляризация нижних конечностей у пациентов с трофическими нарушениями является эффективным методом лечения данной патологии. Поэтому все пациенты с хронической ишемией, угрожающей потерей конечности, должны быть рассмотрены как кандидаты для реваскуляризации.2. При поражении артерий голени или коротких окклюдирующих или стенотических поражениях магистральных артерий такие пациенты должны быть обсуждены совместно со специалистами по рентгенэндоваскулярной хирургии на предмет эндоваскулярного лечения или выполнения вмешательства совместно.3. Гибридный лучевой метод (трехфазная сцинтиграфия и однофотонная эмиссионная компьютерная томография, совмещенная с рентгеновской компьютерной ангиографией) является объективным методом, отображающим состояние периферического кровообращения и микроциркуляции, и позволяет объективно оценить эффективность проведенного лечения

Лечение больных с тромбозами артерий нижних конечностей и коронавирусной инфекцией

The course of severe coronavirus infection is accompanied by hypercoagulability with micro- and macroangiopathy, which may be the cause of arterial and venous thrombosis. In March, 2021 — May 2021, 14 patients with COVID-19 and acute ischemia of the lower extremities due to arterial thrombosis were operated in the Infectious Pavilion of the N.V. Sklifosovsky Research Institute for Emergency Medicine. Retrombosis in the immediate postoperative period developed in 4 patients (26.7%). The amputation at the level of the thigh was performed in 2 patients (13.3%) due to the development of ischemic gangrene. The mortality was 71.4%, 10 patients died. The main cause of death was the progression of multiple organ failure in the course of severe viral-bacterial pneumonia. The best results were obtained with a combination of open surgery and endovascular technique, performing hybrid operations.Течение коронавирусной инфекции в тяжелой форме сопровождается гиперкоагуляцией с микро- и макроангиопатией, что может быть причиной развития артериальных и венозных тромбозов. За период с марта по май 2021 года в инфекционный корпус НИИ СП им. Н.В. Склифосовского поступили и были оперированы 14 пациентов с коронавирусной инфекцией, вызванной COVID-19 и с острой ишемией нижних конечностей вследствие тромбоза артерий. Ретромбоз в ближайшем послеоперационном периоде развился у 4 больных (26,7%). У 2 пациентов (13,3%) была выполнена ампутация на уровне бедра в связи с развитием ишемической гангрены. Летальность составила 71,4%, умерли 10 пациентов. Основной причиной смертельного исхода явились прогрессирование полиорганной недостаточности на фоне тяжелой вирусно-бактериальной пневмонии. Лучшие результаты были получены при сочетании открытой хирургии и эндоваскулярной техники, выполнении гибридных операций

Effect of Cu addition on microstructure and impact toughness in the simulated coarse-grained heat-affected zone of high-strength low-alloy steels

The effects of Cu content on microstructure and impact toughness in the simulated coarse-grained heat-affected zone (CGHAZ) of high-strength low-alloy steels were investigated. It has been observed that the microstructure in the simulated CGHAZ of Cu-free steel is dominated by a small proportion of acicular ferrite and predominantly bainite with martensite–austenite constituent. Whereas, in the 0.45 and 1.01% Cu-containing steels, the acicular ferrite increased significantly due to the effective nucleation on intragranular inclusions with outer layer of MnS and CuS. The formation of acicular ferrite is attributed to superior high heat-affected zone impact toughness in the 0.45% Cu-containing steel. Furthermore, the increasing martensite–austenite constituent and ε-Cu precipitates in the simulated CGHAZ of 1.01% Cu-containing steel caused degradation in impact toughness

On a Theory of Superfluidity of Asymmetric Nuclear Matter

Influence of asymmetry on superfluidity of nuclear matter with triplet-singlet pairing of nucleons (in spin and isospin spaces) is considered within the framework of a Fermi-liquid theory. Solutions of self-consistent equations for the critical temperature and the energy gap at T=0 are obtained. It is shown, that the backward influence of pairing correlations through the normal distribution functions of nucleons leads to the qualitative change: instead of two-valued behavior the energy gap has universal one-valued behavior. At T=0 superfluidity arises as a result of a first order phase transition in density.Comment: The extended version, accepted for publication in Phys. Rev. C as a Rapid Communicatio

Phases of asymmetric nuclear matter with broken space symmetries

Isoscalar Cooper pairing in isospin asymmetric nuclear matter occurs between states populating two distinct Fermi surfaces, each for neutrons and protons. The transition from a BCS-like to the normal (unpaired) state, as the isospin asymmetry is increased, is intervened by superconducting phases which spontaneously break translational and rotational symmetries. One possibility is the formation of a condensate with a periodic crystallinelike structure where Cooper pairs carry net momentum (the nuclear Larkin-Ovchinnikov-Fulde-Ferrell-phase). Alternatively, perturbations of the Fermi surfaces away from spherical symmetry allow for minima in the condensate free energy which correspond to a states with quadrupole deformations of Fermi surfaces and zero momentum of the Cooper pairs. In a combined treatment of these phases we show that, although the Cooper pairing with finite momentum might arise as a local minimum, the lowest energy state features are deformed Fermi surfaces and Cooper pairs with vanishing total momentum.Comment: 22 pages, 6 figures, RevTex; v2: matches published version; v3: changes in the frontmatter, content unchange