Nonconservation of Topological Charge and Cusps in a One-Dimensional Laser Scheme.

An analysis was made of the field structures in a coaxial laser with fast saturable absorption. In such an efficiently one-dimensional scheme, the integer topological index (charge) naturally arises: the phase incursion of the field envelope when bypassing the aperture, divided by 2π. The topological charge is the winding number for the phase curve introduced for the electric field envelope with increase of the coordinate for fixed time. In the framework of the generalized Ginzburg-Landau equation, shown are finite numbers of plane-wave modes, stable with respect to weak perturbations, and solitonlike modes with inhomogeneous intensity distributions and different topological charge. It was found that the topological charge could change during transient to steady state. The events of these changes alternate with formation of cusps of the phase curve occurring when extrema of the field intensity and phase coincide.

Control of topology of two-dimensional solitons in a laser with saturable absorption by means of a coherent holding radiation: publisher's note.

This publisher's note contains corrections to Opt. Lett.45, 3284 (2020)OPLEDP0146-959210.1364/OL.394727.

Control of topology of two-dimensional solitons in a laser with saturable absorption by means of a coherent holding radiation.

We propose a simple method to control the topology of laser vortex solitons and their complexes in a wide-aperture laser with saturable absorption by means of weak coherent holding radiation. The holding radiation acting on initial "free" vortex solitons induces the appearance of new peripheral vortices and the splitting of multiple central vortices, as well as reconfiguration of energy flow topology. A wide variety of these stable vortex structures makes the scheme promising for topologically protected information processing.

Irreversible Hysteresis of Internal Structure of Tangle Dissipative Optical Solitons.

For three-dimensional tangle laser solitons that have a number of unclosed and closed vortex lines and coexist in a range of the scheme parameters, we predict irreversible hysteretic transformation of their internal structure when a system parameter slowly and regularly varies crossing the boundary of the stability of one or another soliton. During the hysteresis cycle, when restoring the initial parameter value, the soliton topology simplifies (decrease of topological indices), its field energy decreases, and the energy of the medium increases. The transient includes a series of elementary reactions: reconnection of vortex lines, separation of closed vortex loops after strong bending of a parent vortex line, and twist of unclosed vortex lines changing topological indices. During the transient, new (metastable) types of localized topological structures arise. It is shown that the tangent energy flow along closed vortex lines is unidirectional or direction alternating.

Topological three-dimensional dissipative optical solitons.

This article presents a review of recent investigations of topological three-dimensional (3D) dissipative optical solitons in homogeneous laser media with fast nonlinearity of amplification and absorption. The solitons are found numerically, with their formation, by embedding two-dimensional laser solitons or their complexes in 3D space after their rotation around a vortex straight line with their simultaneous twist. After a transient, the 'hula-hoop' solitons can form with a number of closed and unclosed infinite vortex lines, i.e. the solitons are tangles in topological notation. They are attractors and are characterized by extreme stability. The solitons presented here can be realized in lasers with fast saturable absorption and are promising for information applications. The tangle solitons of the type described present an example of self-organization that can be found not only in optics but also in various distributed dissipative systems of different types.This article is part of the theme issue 'Dissipative structures in matter out of equilibrium: from chemistry, photonics and biology (part 1)'.

Dynamics of nonlinear Schrödinger breathers in a potential trap.

We consider the evolution of the 2-soliton (breather) of the nonlinear Schrödinger equation on a semi-infinite line with the zero boundary condition and a linear potential, which corresponds to the gravity field in the presence of a hard floor. This setting can be implemented in atomic Bose-Einstein condensates, and in a nonlinear planar waveguide in optics. In the absence of the gravity, repulsion of the breather from the floor leads to its splitting into constituent fundamental solitons, if the initial distance from the floor is smaller than a critical value; otherwise, the moving breather persists. In the presence of gravity, the breather always splits into a pair of "co-hopping" fundamental solitons, which may be frequency locked in the form of a quasi-breather, or unlocked, forming an incoherent pseudo-breather. Some essential results are obtained in an analytical form, in addition to the systematic numerical investigation.

Topological Vortex and Knotted Dissipative Optical 3D Solitons Generated by 2D Vortex Solitons.

We predict a new class of three-dimensional (3D) topological dissipative optical one-component solitons in homogeneous laser media with fast saturable absorption. Their skeletons formed by vortex lines where the field vanishes are tangles, i.e., N_{c} knotted or unknotted, linked or unlinked closed lines and M unclosed lines that thread all the closed lines and end at the infinitely far soliton periphery. They are generated by embedding two-dimensional laser solitons or their complexes in 3D space after their rotation around an unclosed, infinite vortex line with topological charge M_{0} (N_{c}, M, and M_{0} are integers). With such structure propagation, the "hula-hoop" solitons form; their stability is confirmed numerically. For the solitons found, all vortex lines have unit topological charge: the number of closed lines N_{c}=1 and 2 (unknots, trefoils, and Solomon knots links); unclosed vortex lines are unknotted and unlinked, their number M=1, 2, and 3.

A highly conductive electrolyte for molten oxide fuel cells.

A gas-tight and ductile solid/liquid δ-Bi2O3-0.2 wt% B2O3 electrolyte for molten oxide fuel cells (MOFCs) is developed. The MOFCs are a new class of intermediate temperature fuel cells. The composite, consisting of solid (δ-Bi2O3) and liquid (molten Bi2O3 + B2O3) oxygen ion-conducting phases, demonstrates the promising application as an MOFC electrolyte with the highest oxygen ionic conductivity.

Rotating and Precessing Dissipative-Optical-Topological-3D Solitons.

We predict and study a new type of three-dimensional soliton: asymmetric rotating and precessing stable topological-dissipative-optical localized structures in homogeneous media with saturable amplification and absorption. The crucial factor determining their dynamics is the ratio of the diffusion coefficients characterizing the frequency dispersion and angular selectivity (dichroism) of the scheme. These vortex solitons exist and are stable for overcritical values of the selectivity coefficients and can be realized in lasers of large sizes with saturable absorption.

[Clinical aspects of uterine artery embolization efficacy in uterine myomas].

The authors have for the first time evaluated efficacy of embolization of the uterine arteries in uterine myomas depending on peculiarities of the blood flow in the system of the uterine arteries in the context of the B. B. Mandelbrot fractal proportionality.

[Blood plasma zinc and copper concentrations in patients with purulent soft tissue wounds].

The paper considers postoperative imbalance of the trace elements zinc and copper in 40 surgical patients aged 47.2 +/- 17.1 years who have extensive purulent soft tissue wounds (PSTW). In 90% of the patients with PSTW, plasma Zn++ levels were much lower than the reference values (the normal value was 11.1-19.5 micromol/l) while in 47.5%, serum Zn++ was in the range of less than 7 micromol/l, which is a poor prognostic factor. There was a negative correlation between the level of Zn++ and that of C-reactive protein (CRP) and a positive correlation between the former and the magnitude of a reduction in transferrin (TF) as a marker of protein-energy malnutrition. Plasma Cu/Zn ratio is shown to be of very clinical importance. The higher this ratio (normal ratio 0.9-1.13) is, the more severe the general condition of patients with PSTW, the higher CRP values (above 120 mg/l; normal value 0-6 mg/l), and the lower TF levels are. In patients with PSTW, zinc level and Cu/Zn ratio may act as an independent predictor of a grave condition during a systemic inflammatory reaction.

[Our experience of resection of extramedullary spinal tumors using hemilaminectomy and microsurgical technique].

The paper contains results of surgical treatment of 52 patients with extramedullary spinal tumors. Resection of tumors was performed using hemilaminectomy and microsurgical technique. In all cases tumors were resected totally. Follow-up data are also presented (periods of follow-up ran to 6-10 years). Control examination was complemented by MRI and X-ray spondilograms. No signs of instability and other complications were found. With reference to our own experience and literature data we discuss the possibilities of radical resection of extramedullary tumors via hemilaminectomy. This allows to avoid postoperative vertebral instability. At the same time we emphasize that despite minimally traumatic approach and high effectiveness in removal of lateral and dorsolateral tumors, hemilaminectomy in certain degree limits possibilities of radical resection of tumors located someway ventrally.

[Sipping as a mode of correction of protein-calorie deficiency in intensive care unit patients].

The paper presents the results of postoperative studies in 82 patients with major soft tissue phlegmons of the extremities and torso. The basic aspect of the studies concerned the correction of protein-calorie deficiency on the basis of additional nutrition through sipping of hypercaloric formula "Nutridrink" and the standard enteral formula "Nutrisone dry powder", which were given to in 29 and 20 patients, respectively, on postoperative day 1 for 3 weeks. A control group comprised 33 patients who received only diet 1. The findings have indicated that sipping of the enteral formula substantially reduces the catabolic pattern in the patients and facilitates a rapider recovery of the visceral protein pool.

[Characterization of the current foci of tuberculous infection].

The epidemic foci formed by patients with tuberculosis in the Admiralteisky District, Saint Petersburg in 1994-2005 were surveyed. The study showed that the bulk of the foci had been formed by patients suffering from the clinical forms of tuberculosis without the chronic pattern of a process, that of first-grade epidemic burden. These are most commonly the foci of new-onset tuberculosis; the proportion of comers from other areas and confinement institutions was not greater than 15%. The one-year foci formed by the patients living in the communal flats made up their bulk. Under the conditions of a megapolis, the cases of small epidemic are extremely few and they do not affect the intensity of the bacillary nucleus in the population of the district. The contribution of the foci formed by the homeless and migrants to the formation of the bacillary nucleus was small, but showed a stable upward trend. Every five focus was that of drug-resistant tuberculosis and they were shown to tend to increase.

[Comparative assessment of general and regional anesthesia during total endoprosthetic operations on the knee joint].

The present paper comparatively analyzes anesthetic support in 91 patients during a total endoprosthetic operation on the knee joint. All the patients were conventionally divided into 4 groups: (1) those (n=7) in whom the operation had been made under general anesthesia (nitrous oxide, ketamine, seduxen, droperidol, and fentanyl); (2) those (n=36) who had been operated on under epidural anesthesia; (3) those (n=24) who had intraoperatively received spinal (subarachnoidal) anesthesia; (4) those (n=24) whom had been intraoperatively given combined spinal and epidural anesthesia. The study established that the above-mentioned general anesthesia failed to produce a steady-state hemodynamics; the earliest postoperative period being accompanied by a significant pain syndrome, which required the use of narcotic analgesics. In Group 2, due to the specific features of the impact of epidural anesthesia itself on different innervation links (A, B, and C), susceptibility to hypotension and the adequacy of this mode of anesthesia were observed, which required the intraoperative additional administration of narcotic agents to enhance anesthesia. Group 3 was marked by a relative postoperative stability of parameters, but a significant pain syndrome is observed in the earliest postoperative period. The best results were obtained in Group 4 patients undeigone a combined spinal and epidural anesthesia. The component of subarachnoidal (spinal) anesthesia Marcaine Spinal provided a sufficient intraoperative analgesic effect and the component of epidural anesthesia induced virtually no pain syndrome under continuous epidural block.

Polarization state of quadratic spatial optical solitons.

We derive governing equations that determine a full polarization state of transversely two-dimensional spatial solitons in a bulk anisotropic medium with the second-order nonlinearity. Based on nonlinear vectorial Maxwell's equations and approximation of slowly varying envelopes, our approach describes also lowest-order nonparaxial effects, however the most important factor governing radiation polarization is the medium anisotropy. This factor results in mixing of orthogonal components of electric field of quadratic soliton that consists of coupled beams at the fundamental frequency and its second harmonics. For the case of weak anisotropy we determine the soliton polarization state by a perturbation method; it turns out that it is elliptical and changing over the soliton transverse section. The approach allows generalization to the case of optical parametric oscillators.

[Clinical and morphological aspects of Helicobacter pylori invasion in reflux esophagitis]. / Kliniko-morfologicheskie aspekty invazii Helicobacter pylori pri refliuks ezofagite.

The mucosal biopsies morphological investigation of the lower third of esophagus were conducted for Helicobacter pylori detection in 43 patients with reflux-esophagitis. Helicobacter pylori were detected in 66.7%, gastric metaplasia-in 83.3% of patients. Helicobacter pylori plays an important role in reflux-esophagitis pathogenesis. Surgical treatment is indicated if the combined antireflux and antibacterial therapy is ineffective.

[First experience with the surgical treatment of young infants with congenital pathology of the locomotor system]. / Pervyi opyt khirurgicheskogo lecheniia detei rannego vozrasta s vrozhdennoi patologiei oporno-dvigatel'nogo apparata.

The authors have revised traditional principles of treatment of children with a congenital pathology of the locomotor system. Early treatment has been shown to be necessary beginning from infancy since the operations have a more favourable course. Normal anatomo-physiological correlations of the locomotor system are being formed from the early days and months of the infants. Good immediate results were obtained in 22 children. The authors recommend to establish terms of the operative interventions for orthopedic abnormalities immediately after birth in the maternity home.