[Direct transfistulous ultrasound in minimally invasive surgical treatment of infected pancreatic necrosis]. / Pryamoe chresfistul'noe ul'trazvukovoe issledovanie pri minimal'no invazivnom khirurgicheskom lechenii patsientov s infitsirovannym pankreonekrozom.

OBJECTIVE: To develop a method for direct transfistulous ultrasound in minimally invasive treatment of infected pancreatic necrosis. MATERIAL AND METHODS: There were 148 patients with infected pancreatic necrosis between 2015 and 2019 at the Krasnodar City Clinical Hospital No. 2. Drainage with 28-32 Fr tubes was carried out at the first stage, endoscopic transfistulous sequestrectomy - at the second stage (19 (12.8%) patients). In 84 (56.8%) patients, we applied original diagnostic method (transfistulous ultrasonic assessment of inflammatory focus). RESULTS: There were 3 accesses to omental bursa in 93 (62.8%) patients and 2 in 43 (29.1%) patients. We also performed 2 access to retroperitoneal space in 63 (42.6%) patients and 1 access in 38 (25.8%) cases. Transfistulous ultrasound was used once in 19 (22.6%) patients, twice in 28 (33.3%) and 3 times in 37 (44.1%) patients. Examination was not performed in 18 (12.2%) patients due to the following reasons: migration of drainage catheters - 5, non-rectilinear fistulous tract - 13. No complications were observed. CONCLUSION: Transfistulous ultrasound makes it possible to diagnose pathological changes in the pancreas and parapancreatic tissue at various stages of surgical treatment.

[Technological features of open and minimally invasive surgical treatment of local complications of purulent-necrotic pancreatitis]. / Sravnenie tekhnologicheskikh osobennostei primeneniya otkrytykh i minimal'no invazivnykh sposobov khirurgicheskogo lecheniya mestnykh oslozhnenii gnoino-nekroticheskogo pankreatita.

There are various options for surgical treatment of purulent-necrotic pancreatitis with significant technological differences. Combining surgical methods other than traditional ones into a group of minimally invasive ones based on the principle of the absence of standard laparotomy is not entirely correct. The review presents modern methods of surgical treatment of acute pancreatitis, comparison of their technology regarding classical stages of surgical intervention and their classification.

[A modified method for percutaneous drainage of acute necrotic collections in patients with infected pancreatic necrosis]. / Modifitsirovannyi metod chreskozhnogo drenirovaniya ostrykh nekroticheskikh skoplenii u patsientov s infitsirovannym pankreonekrozom.

OBJECTIVE: To develop a modified method for percutaneous drainage of acute necrotic collections in patients with infected pancreatic necrosis. MATERIALS AND METHODS: Minimally invasive surgical technologies were used in 74 patients with infected acute necrotic collections at the Krasnodar Regional Clinical Hospital No. 2 between 2017 and 2019. Of these, 59 (79.7%) people underwent percutaneous drainage as a final treatment. In 11 (14.9%) patients, video sequestrectomy through the fistula was additionally used to increase efficiency of percutaneous drainage. RESULTS: PCD in our modification implies delivery of double-lumen drains 26-32 Fr in the same plane to zones of necrosis, their programmed replacement for prevention of obstruction and flexible endoscopy for control of pathological process. Local purulent-necrotic parapancreatitis occurred in 31 (41.9%) patients, widespread parapancreatitis - in 43 (58.1%) patients. There were 339 minimally invasive interventions. Laparotomy was required in 4 (5.4%) patients. Incidence of perioperative complications was 10.6%, mortality - 16.2%. CONCLUSION: A modified percutaneous drainage method may be used as final surgical treatment in 79.7% of patients with infected pancreatic necrosis.

[Transfistulous endoscopic sequestrectomy in the treatment of infected pancreatic necrosis]. / Sposob chresfistul'noi videoskopicheskoi nekrsekvestrektomii v lechenii infitsirovannogo pankreonekroza.

OBJECTIVE: To develop an effective minimally invasive method for the treatment of infected pancreatic necrosis. MATERIAL AND METHODS: There were 168 patients with infected pancreatic necrosis who were treated at the Regional Clinical Hospital No. 2 between 2011 and 2018. Eighty-seven (51.8%) patients underwent primary drainage with large-diameter double-lumen drains 28-32 Fr, and original technique of transfistulous endoscopic sequestrectomy was used. Puncture-drainage interventions with transfistulous endoscopic sequestrectomy were used in 23 (26.4%) patients with local and 64 (73.6%) patients with widespread purulent-necrotic parapancreatitis. RESULTS: Percutaneous channels are accesses to purulent-necrotic cavity and used for transfistulous endoscopic sequestrectomy. This procedure was performed 98 times. Time of primary sanitation in patients with 3 accesses in omental bursa was significantly less compared to 2 accesses (62±4.3 vs. 89±8.2 min, p<0.05). In case of repeated sanitation, time of intervention did not depend on the number of accesses. Incidence of local complications was 9.1%, extra-abdominal complications - 19.4%. Mortality rate was 12.6%. CONCLUSION: Original technique of transfistulous endoscopic sequestrectomy increases efficiency of sanitation of infected parapancreatitis, improves treatment outcomes and reduces mortality to 12.3%.

[Cutaneous and visceral leishmaniasis in patients with HIV infection in Russia. Case report].

The article contains information on the problem of the combined course of HIV infection and leishmaniasis: a number of statistical and overview data in the world. It also presents a brief description of known cases of HIV patients with leishmaniasis in the Russian Federation. In all cases the diagnostics of leishmaniasis was difficult due to the lack of alertness of physicians to this illness, as well as poor knowledge of epidemiological situation of leishmaniasis. All patients with visceral leishmaniasis but one caught it during their stay in Crimea. Cutaneous leishmaniasis was described in HIV infection in the Russian Federation for the second time and is associated with the patient's residence in the Chechen Republic.

[Minimally invasive surgical interventions in the treatment of severe acute pancreatitis]. / Mini-invazivnye khirurgicheskie vmeshatel'stva v lechenii patsientov s ostrym pankreatitom tyazheloi stepeni.

OBJECTIVE: To improve the outcomes in patients with severe destructive pancreatitis undergoing minimally invasive surgery. MATERIAL AND METHODS: There were 482 patients with acute destructive pancreatitis for the period from 2007 to 2016. Non-infected acute destructive pancreatitis was diagnosed in 58% (n=280) of patients, infected pancreatic necrosis - in 42% (n=202) of patients. Minimally invasive technologies were used in the treatment of purulent complications of destructive pancreatitis: endoscopic papillotomy, percutaneous puncture of fluid accumulations, ultrasound- and X-ray-assisted drainage of abscesses and retroperitoneal phlegmon. RESULTS: There were 688 drainage surgeries in 92 patients with infected pancreatic necrosis: US-assisted Seldinger drainage - 599 (87%), single-stage drainage - 89 (13%) cases. Percutaneous transfistular retroperitoneal interventions were made in 72 patients (one intervention - 29 patients, redo procedures - 43 patients). Complications associated with minimally invasive procedures developed in 2.7% (19) of cases. Six patients required laparotomy. Mean length of hospital-stay was 36.5 days. Mean rate of restitution of post-necrotic areas was 37.7 days. CONCLUSION: Minimally invasive procedures reduce overall mortality up to 6% in patients with acute pancreatitis and up to 14% in those with destructive forms of inflammation.

Microscopic Nature of the First-Order Field-Induced Phase Transition in the Strongly Anisotropic Ferrimagnet HoFe_{5}Al_{7}.

We report on x-ray magnetic circular dichroism experiments in pulsed fields up to 30 T to follow the rotations of individual magnetic moments through the field-induced phase transition in the ferrimagnet HoFe_{5}Al_{7}. Near the ground state, we observe simultaneous stepwise rotations of the Ho and Fe moments and explain them using a two-sublattice model for an anisotropic ferrimagnet with weak intersublattice exchange interactions. Near the compensation point, we find two phase transitions. The additional magnetization jump reflects the fact that the Ho moment is no longer rigid as the applied field acts against the intersublattice exchange field.

Hybrid Sound Modes in One-Dimensional Quantum Liquids.

We study sound in a single-channel one-dimensional quantum liquid. In contrast to classical fluids, instead of a single sound mode we find two modes of density oscillations. The speeds at which these two sound modes propagate are nearly equal, with the difference that scales linearly with the small temperature of the system. The two sound modes emerge as hybrids of the first and second sounds, and combine oscillations of both density and entropy of the liquid.

Longitudinal Negative Magnetoresistance and Magnetotransport Phenomena in Conventional and Topological Conductors.

Recently, a large negative longitudinal (parallel to the magnetic field) magnetoresistance was observed in Weyl and Dirac semimetals. It is believed to be related to the chiral anomaly associated with topological electron band structure of these materials. We show that in a certain range of parameters such a phenomenon can also exist in conventional centrosymmetric and time-reversal invariant conductors, lacking topological protection of the electron spectrum and the chiral anomaly. We also discuss the magnetic field enhancement of the longitudinal components of the thermal conductivity and thermoelectric tensors.

Second Sound in Systems of One-Dimensional Fermions.

We study sound in Galilean invariant systems of one-dimensional fermions. At low temperatures, we find a broad range of frequencies in which in addition to the waves of density there is a second sound corresponding to the ballistic propagation of heat in the system. The damping of the second sound mode is weak, provided the frequency is large compared to a relaxation rate that is exponentially small at low temperatures. At lower frequencies, the second sound mode is damped, and the propagation of heat is diffusive.

Anomalous Hall Effect in Type-I Weyl Metals.

We study the ac anomalous Hall conductivity σ_{xy}(ω) of a Weyl semimetal with broken time-reversal symmetry. Even in the absence of free carriers these materials exhibit a "universal" anomalous Hall response determined solely by the locations of the Weyl nodes. We show that the free carriers, which are generically present in an undoped Weyl semimetal, give an additional contribution to the ac Hall conductivity. We elucidate the phy146sical mechanism of the effect and develop a microscopic theory of the free carrier contribution to σ_{xy}(ω). The latter can be expressed in terms of a small number of parameters (the electron velocity matrix, the Fermi energy µ, and the "tilt" of the Weyl cone). The resulting σ_{xy}(ω) has resonant features at ω∼2µ which may be used to separate the free carrier response from the filled-band response using, for example, Kerr effect measurements. This may serve as a diagnostic tool to characterize the doping of individual valleys.

Magneto-elastic coupling across the first-order transition in the distorted kagome lattice antiferromagnet Dy3Ru4Al12.

Structural changes through the first-order paramagnetic-antiferromagnetic phase transition of Dy3Ru4Al12 at 7 K have been studied by means of X-ray diffraction and thermal expansion measurements. The compound crystallizes in a hexagonal crystal structure of Gd3Ru4Al12 type (P63/mmc space group), and no structural phase transition has been found in the temperature interval between 2.5 and 300 K. Nevertheless, due to the spin-lattice coupling the crystal volume undergoes a small orthorhombic distortion of the order of 2×10-5 as the compound enters the antiferromagnetic state. We propose that the first-order phase transition is not driven by the structural changes but rather by the exchange interactions present in the system.

UH3-based ferromagnets: new look at an old material.

UH3 is the first discovered material with ferromagnetism based purely on the 5f electronic states, known for more than half century. Although the U metal is Pauli paramagnet, the reduced 5f-5f overlap in compounds allows for moment formation and ordering, typically if the U-U spacing exceeds the Hill limit, i.e. about 340 pm. The stable form of UH3, known as ß-UH3, has rather high TC ≈ 170 K. Such high value is rather unusual, considering dU-U = 331 pm. Properties of metastable α-UH3 with dU-U = 360 pm could be never well established. Using the fact that α-UH3 is in fact bcc U with interstitials filled by H, we attempted to synthesize α-UH3 starting from the γ-U alloys, with the bcc structure retained to room temperature by doping combined with ultrafast cooling. While up to 15% Zr a contamination by ß-UH3 was obtained, 20% Zr yielded single phase α-UH3. The TC value remains high and very similar to ß-UH3. One can see an increase up to 187 K for 15% Zr, followed by a weak decrease. Magnetic moments remain close to 1 µB/U atom. An insight is provided by ab-initio calculations, revealing a a charge transfer towards H-1s states, depopulating the U-6d and 7s states, leaving almost pure 5f character around the Fermi level. The 5f magnetism exhibits a high coercivity (µ0Hc up to 5.5 T) and large spontaneous volume magnetostriction of 3.2*10-3. Even higher increase of TC, reaching up to 203 K, can be achieved in analogous Mo stabilized hydrides, which yield an amorphous structure. The compounds represent, together with known hydrides of U6Fe and U6Co, a new group of robust 5f ferromagnets with small dU-U but high TC. Although common hydrides are fine powders, some of the new hydrides described as (UH3)(1-x)T x (T = Zr or Mo) remain monolithic, which allows to study transport and thermodynamic properties.

Aharonov-Bohm oscillations in singly connected disordered conductors.

We show that the transport and thermodynamic properties of a singly connected disordered conductor exhibit quantum Aharonov-Bohm oscillations as a function of the total magnetic flux through the sample. The oscillations are associated with the interference contribution from a special class of electron trajectories confined to the surface of the sample.

Quantum criticality in a Mott pn junction in an armchair carbon nanotube.

In an armchair carbon nanotube pn junction the p and n regions are separated by a region of a Mott insulator, which can backscatter electrons only in pairs. We predict a quantum-critical behavior in such a pn junction. Depending on the junction's built-in electric field E, its conductance G scales either to zero or to 4e(2)/h as the temperature T is lowered. The two types of the G(T) dependence indicate the existence, at some special value of E, of an intermediate quantum-critical point with a finite conductance G<4e(2)/h. This makes the pn junction drastically different from a simple potential barrier in a Luttinger liquid.

Hydrodynamic description of transport in strongly correlated electron systems.

We develop a hydrodynamic description of the resistivity and magnetoresistance of an electron liquid in a smooth disorder potential. This approach is valid when the electron-electron scattering length is sufficiently short. In a broad range of temperatures, the dissipation is dominated by heat fluxes in the electron fluid, and the resistivity is inversely proportional to the thermal conductivity, κ. This is in striking contrast to the Stokes flow, in which the resistance is independent of κ and proportional to the fluid viscosity. We also identify a new hydrodynamic mechanism of spin magnetoresistance.

Equilibration of Luttinger liquid and conductance of quantum wires.

Luttinger liquid theory describes one-dimensional electron systems in terms of noninteracting bosonic excitations. In this approximation thermal excitations are decoupled from the current flowing through a quantum wire, and the conductance is quantized. We show that relaxation processes not captured by the Luttinger liquid theory lead to equilibration of the excitations with the current and give rise to a temperature-dependent correction to the conductance. In long wires, the magnitude of the correction is expressed in terms of the velocities of bosonic excitations. In shorter wires it is controlled by the relaxation rate.

Hydrodynamics of liquids of chiral molecules and suspensions containing chiral particles.

We obtain hydrodynamic equations describing a fluid consisting of chiral molecules or a suspension of chiral particles in a Newtonian fluid. The hydrodynamic velocity and stresses arising in a flowing chiral liquid have components that are forbidden by symmetry in a Newtonian liquid. For example, a chiral liquid in a Poiseuille flow between parallel plates exerts forces on the plates, which are perpendicular to the flow. A generic flow results in spatial separation of particles of different chirality. Thus even a racemic suspension will exhibit chiral properties in a generic flow. A suspension of particles of random shape in a Newtonian liquid is described by equations which are similar to those describing a racemic mixture of chiral particles in a liquid.

Equilibration of a one-dimensional Wigner crystal.

Equilibration of a one-dimensional system of interacting electrons requires processes that change the numbers of left- and right-moving particles. At low temperatures such processes are strongly suppressed, resulting in slow relaxation towards equilibrium. We study this phenomenon in the case of spinless electrons with strong long-range repulsion, when the electrons form a one-dimensional Wigner crystal. We find the relaxation rate by accounting for the umklapp scattering of phonons in the crystal. For the integrable model of particles with inverse-square repulsion, the relaxation rate vanishes.

A high-field magnetization study of a Nd(2)Fe(14)Si(3) single crystal.

Magnetization study of a single crystal of Nd(2)Fe(14)Si(3) (with the rhombohedral Th(2)Zn(17)-type structure) reveals that the compound is a ferromagnet with a spontaneous magnetic moment of 32.3µ(B) per formula unit (at T = 2 K) and a Curie temperature equal to 495 K. The easy-magnetization direction lies close to the b-axis, tilting slightly towards the c-axis. (The b-axis [120] is not a high-symmetry direction in the crystallographic class D(3d).) The observed strong magnetic anisotropy is attributed almost entirely to the Nd sublattice, as concluded from comparison with a Y(2)Fe(14)Si(3) single crystal. A magnetic field applied along the c-axis induces a first-order spin reorientation transition at B(FOMP) = 20 T. In the process of magnetization the Nd and Fe sublattices behave as essentially non-collinear. This is manifest particularly in the downward curvature of the first (pre-FOMP) stage of the magnetization curve. It is proposed to regard this curvature as a validity criterion for the single-sublattice approximation.