[Diagnosis and treatment of kidney damage following stab and blunt abdominal injuries]. / Diagnostika i lechenie povrezhdenii pochek pri zakrytykh travmakh i koloto-rezanykh raneniyakh zhivota.

OBJECTIVE: To improve treatment outcomes in victims with kidney damage following blunt and stab abdominal trauma by using of minimally invasive methods of diagnosis and treatment. MATERIAL AND METHODS: About 1.2-3.5% of all victims arrived to the Dzhanelidze St. Petersburg Research Institute for Emergency Care have kidney injuries. We analyzed the results of treatment of 117 patients with isolated and combined blunt and stab abdominal injuries. The retrospective (2014-2017) group included 62 victims, and the prospective (2018-2021) group enrolled 55 patients who were treated according to the new algorithm. This algorithm included non-surgical and minimally invasive management for patients with systolic blood pressure >90 mm Hg after contrast-enhanced CT. Angiography with selective embolization was required for ongoing bleeding. We analyzed incidence of open interventions, organ-sparing procedures, complications, duration of treatment and mortality. Between-group differences were assessed using the χ2 test and Student's test. RESULTS: In both groups, kidney damage in most victims with abdominal trauma was due to road accident and catatrauma. Most patients had combined abdominal injuries, mainly in combination with head and chest lesions. Severity of injuries and clinical condition were similar in both groups. In the retrospective group, there were 9 laparotomies with nephrectomy. Nephrorraphy was performed in 8 cases, kidney vessel suture - in 4 patietns. In the prospective group, nephrectomy was performed in 3 patients with unstable hemodynamics and injuries AAST grade V. Nephrorraphy was performed in 4 victims. In one case, vascular suture was applied for tangential vein damage. All laparoscopies in both groups were diagnostic without nephrectomy. We used non-surgical treatment in 34 patients of the prospective group. One patient underwent angiography and selective embolization of renal artery branches. There were no significant between-group differences in the incidence of infectious and non-infectious complications. Mortality rate was 30.6% (n=19) and 27.3% (n=15) in the retrospective and prospective groups, respectively. CONCLUSION: The proposed algorithm for kidney injury made it possible to reduce the incidence of laparoscopies and laparotomies by 2 times, preserve the damaged kidney in 94.5% of cases and avoid invasive treatment in 62% of victims.

[Primary retrograde distal access for endovascular interventions in patients with lower limb ischemia]. / Pervichnyi retrogradnyi distal'nyi dostup pri endovaskulyarnykh vmeshatel'stvakh u patsientov s ishemiei nizhnikh konechnostei.

OBJECTIVE: To evaluate safety and technical efficiency of primary retrograde distal access for endovascular interventions in patients with lower limb ischemia. MATERIAL AND METHODS: A prospective analysis included 25 endovascular procedures via primary retrograde distal access in 23 patients with chronic obliterating diseases of lower limb arteries. Occlusive lesion of femoral-popliteal segment was observed in 68% of cases, occlusion of at least one tibial artery was also found in 68% of cases. In 44% of cases, occlusive lesion was localized at several levels. Percutaneous intervention via anterior tibial artery or dorsalis pedis artery was performed in 68% of cases, posterior tibial artery - 24% of cases, peroneal artery - 8% of cases. We used 2 accesses in 92% of cases (the main one for intervention and additional one for angiography). In 8% of cases, intervention was carried out through a single access. Angiosome artery was punctured in 65% of cases. The only patent tibial vessel was used in 20% of cases. In 24% of cases, we performed antegrade recanalization of 'adjacent' tibial artery via distal access. RESULTS: Primary retrograde distal access was successfully performed in 100% of cases. Retrograde revascularization was not successful in all cases (successful recanalization rate 96%, retrograde intervention rate - 92%). Femoral access was performed in 8% of cases. Antegrade blood flow through at least one tibial artery was restored in all cases. Direct revascularization of the affected angiosome was performed in 15 patients with foot necrosis, indirect revascularization through collaterals - in 5 patients. Local complications of surgical access occurred in 12% of cases. CONCLUSION: Endovascular revascularization via primary retrograde distal access was technically effective in most cases. There were no complications with systemic consequences.

Thermoelectric Transport in a Three-Channel Charge Kondo Circuit.

We theoretically investigate the thermoelectric transport through a circuit implementation of the three-channel charge Kondo model quantum simulator [Z. Iftikhar et al., Science 360, 1315 (2018)SCIEAS0036-807510.1126/science.aan5592]. The universal temperature scaling law of the Seebeck coefficient is computed perturbatively approaching the non-Fermi liquid strong coupling fixed point using the Abelian bosonization technique. The predicted T^{1/3}logT scaling behavior of the thermoelectric power sheds light on the properties of Z_{3} emerging parafermions and gives access to exploring prefractionalized zero modes in the quantum transport experiments. We discuss a generalization of approach for investigating a multichannel Kondo problem with emergent Z_{N}→Z_{M} crossovers between "weak" non-Fermi liquid regimes corresponding to different low-temperature fixed points.

Conformational equilibria of pharmaceuticals in supercritical CO2, IR spectroscopy and quantum chemical calculations.

In this work we demonstrate a self-consistent effective technique of analyzing the conformational equilibria of active pharmaceutical ingredient (API) molecules dissolved in supercritical carbon dioxide in a wide range of thermodynamic parameters of state. This approach can be useful for pharmaceutics when the crystalline forms of pharmaceuticals with a high purity degree and desirable polymorphism are produced using CO2-based supercritical fluids technologies. Within this approach we use a combination of quantum chemical calculations and in situ IR spectroscopy. Quantum chemical calculations allow us to perform the initial conformational search and to determine the energy characteristics of the most stable conformers of API and the energy barriers of transitions between them. IR spectroscopy gives the information on the equilibrium of the most stable conformers of pharmaceuticals dissolved in scCO2 in the thermodynamic parameter range of interest. Finally we validate our approach by applying it to the study of carbamazepine dissolved in scCO2 being in permanent contact with an excess of crystalline carbamazepine as an example. The conformational search for carbamazepine molecules in scCO2 was also performed using molecular dynamics simulation for comparison with the results obtained by the technique presented in this paper.

Effect of DMSO, urea and ethanol on hydration of stratum corneum model membrane based on short-chain length ceramide [AP].

Hydration of oriented multilamellar membrane based on ceramide [AP] in the DMSO, urea and ethanol aqueous solutions at various solute concentrations was investigated by neutron diffraction. Neither urea nor DMSO influence the repeat distance of the membrane and internal structure of bilayer at their mole concentration of up to 0.15 and 0.10, respectively. The d-spacing reduction effect of both compounds was observed at their concentrations of 0.2 for urea and 0.2 and 0.4 for DMSO. Compared to hydration in the pure water, both urea and DMSO slow down the swelling process, and this slowdown is more pronounced with increasing in their concentration. At concentration of 0.2, urea and DMSO induce the slight phase separation of the fully hydrated samples; at the highest used concentration of 0.6, DMSO induces the strong time-depend separation of the sample probably due to fluidization of lipid bilayers. Ethanol at a used molar concentration of 0.03 leads to dissolution of the sample.

Flory-type theories of polymer chains under different external stimuli.

In this Review, we present a critical analysis of various applications of the Flory-type theories to a theoretical description of the conformational behavior of single polymer chains in dilute polymer solutions under a few external stimuli. Different theoretical models of flexible polymer chains in the supercritical fluid are discussed and analysed. Different points of view on the conformational behavior of the polymer chain near the liquid-gas transition critical point of the solvent are presented. A theoretical description of the co-solvent-induced coil-globule transitions within the implicit-solvent-explicit-co-solvent models is discussed. Several explicit-solvent-explicit-co-solvent theoretical models of the coil-to-globule-to-coil transition of the polymer chain in a mixture of good solvents (co-nonsolvency) are analysed and compared with each other. Finally, a new theoretical model of the conformational behavior of the dielectric polymer chain under the external constant electric field in the dilute polymer solution with an explicit account for the many-body dipole correlations is discussed. The polymer chain collapse induced by many-body dipole correlations of monomers in the context of statistical thermodynamics of dielectric polymers is analysed.

[Assessment of functional state of microcirculatory bed of the foot in patients with lower limb critical ischaemia]. / Otsenka funktsional'nogo sostoianiia mikrotsirkuliatornogo rusla stopy u bol'nykh s kriticheskoi ishemiei nizhnikh konechnostei.

The authors assessed perfusion of the foot in patients presenting with lower limb critical ischaemia before and after endovascular revascularization, as well as analysed the interrelationship between the change of perfusion and the clinical result of treatment. The study includes a total of 15 patients presenting with ulcerative-necrotic defects of the foot. All patients underwent study of 2D-perfusion of the foot before and after the endovascular intervention. The '2D-perfusion' package was used within the framework of an angiographic examination, and required neither increase in the volume of the contrast medium nor radiation load. Four parameters of perfusion were evaluated: the time of ingress, the time of reaching the peak value, the peak value and the area under the curve. After the intervention, as compared with the baseline values there were statistically significant differences by the time of ingress (a 2.4-fold decrease; p<0.0001), the peak value (a 1.8-fold increase; p<0.0001) and the area under the curve (a 2.4-fold increase; p<0.0001). No statistically significant differences were revealed while comparing the time of reaching the peak value before and after the intervention (p=0.767). Trophic defects healed in 11 (73.3%) patients, and in 4 (26.7%) patients the process of healing continued with positive dynamics at the check-up examination. Hence, our first experience of using the assessment of 2D-perfusion demonstrates simplicity of the method with no increase of the radiation load and the dose of the contrast medium. The method makes it possible to obtain important data about the state of microcirculation of the foot in patients with lower limb critical ischaemia, to evaluate alterations after the endovascular intervention. Improvement of the parameters of perfusion is associated with a good clinical outcome.

Correction: Statistical theory of polarizable target compound impregnation into a polymer coil under the influence of an electric field.

Correction for 'Statistical theory of polarizable target compound impregnation into a polymer coil under the influence of an electric field' by A. L. Kolesnikov et al., Soft Matter, 2017, DOI: 10.1039/c7sm00417f.

Statistical theory of polarizable target compound impregnation into a polymer coil under the influence of an electric field.

The paper presents a theoretical approach for describing the influence of an electric field on the conformation of an electrically neutral dielectric polymer chain dissolved in a dielectric solvent with an admixture of a target compound. Each monomer and each molecule of the target compound carries positive excess polarizability and the solvent is described as a continuous dielectric medium. The model is based on the Flory-type mean-field theory. We demonstrate non-monotonic dependences of the expansion factor and the concentration of the target compound on the strength of the electric field and molecular polarizability. Namely, the target compound concentration in the internal polymer volume as a function of electric field strength has pronounced maxima if the molecules are polarizable. In addition, the expansion factor of the non-polarizable polymer chain can be controlled by the electric field. The dependences of the expansion factor and target compound concentration on the monomer polarizability exhibit minima and intersection points. The intersection points correspond to the equality of dielectric permittivities in the bulk solution and in the internal polymer volume.

Short periodicity phase based on ceramide [AP] in the model lipid membranes of stratum corneum does not change during hydration.

Small angle X-ray scattering technique was used to determine electron density profiles of short periodicity phase in the model lipid membranes of stratum corneum at different pH. Basic quaternary system was prepared as used previously in the neutron experiments at partial hydration. It was shown that electron density profiles of partially hydrated and fully hydrated model lipid membranes with four basic components were quite similar and demonstrated almost no interbilayer water.

Coupled multiple-mode theory for s± pairing mechanism in iron based superconductors.

We investigate the interplay between the magnetic and the superconducting degrees of freedom in unconventional multi-band superconductors such as iron pnictides. For this purpose a dynamical mode-mode coupling theory is developed based on the coupled Bethe-Salpeter equations. In order to investigate the region of the phase diagram not too far from the tetracritical point where the magnetic spin density wave, (SDW) and superconducting (SC) transition temperatures coincide, we also construct a Ginzburg-Landau functional including both SC and SDW fluctuations in a critical region above the transition temperatures. The fluctuation corrections tend to suppress the magnetic transition, but in the superconducting channel the intraband and interband contribution of the fluctuations nearly compensate each other.

Spin-mediated Photomechanical Coupling of a Nanoelectromechanical Shuttle.

We show that nanomechanical vibrations in a magnetic shuttle device can be strongly affected by external microwave irradiation through photo-assisted electronic spin-flip transitions. Mechanical consequences of these spin flips are due to a spin-dependent magnetic force, which may lead to a nanomechanical instability in the device. We derive a criterion for the instability to occur and analyze different regimes of nanomechanical oscillations. Possible experimental realizations of the spin-mediated photomechanical instability and detection of the device backaction are discussed.

On the theory of electric double layer with explicit account of a polarizable co-solvent.

We present a continuation of our theoretical research into the influence of co-solvent polarizability on a differential capacitance of the electric double layer. We formulate a modified Poisson-Boltzmann theory, using the formalism of density functional approach on the level of local density approximation taking into account the electrostatic interactions of ions and co-solvent molecules as well as their excluded volume. We derive the modified Poisson-Boltzmann equation, considering the three-component symmetric lattice gas model as a reference system and minimizing the grand thermodynamic potential with respect to the electrostatic potential. We apply present modified Poisson-Boltzmann equation to the electric double layer theory, showing that accounting for the excluded volume of co-solvent molecules and ions slightly changes the main result of our previous simplified theory. Namely, in the case of small co-solvent polarizability with its increase under the enough small surface potentials of electrode, the differential capacitance undergoes the significant growth. Oppositely, when the surface potential exceeds some threshold value (which is slightly smaller than the saturation potential), the increase in the co-solvent polarizability results in a differential capacitance decrease. However, when the co-solvent polarizability exceeds some threshold value, its increase generates a considerable enhancement of the differential capacitance in a wide range of surface potentials. We demonstrate that two qualitatively different behaviors of the differential capacitance are related to the depletion and adsorption of co-solvent molecules at the charged electrode. We show that an additive of the strongly polarizable co-solvent to an electrolyte solution can shift significantly the saturation potential in two qualitatively different manners. Namely, a small additive of strongly polarizable co-solvent results in a shift of saturation potential to higher surface potentials. On the contrary, a sufficiently large additive of co-solvent shifts the saturation potential to lower surface potentials. We obtain that an increase in the co-solvent polarizability makes the electrostatic potential profile longer-ranged. However, increase in the co-solvent concentration in the bulk leads to non-monotonic behavior of the electrostatic potential profile. An increase in the co-solvent concentration in the bulk at its sufficiently small values makes the electrostatic potential profile longer-ranged. Oppositely, when the co-solvent concentration in the bulk exceeds some threshold value, its further increase leads to decrease in electrostatic potential at all distances from the electrode.

Communication: Polarizable polymer chain under external electric field in a dilute polymer solution.

We study the conformational behavior of polarizable polymer chain under an external homogeneous electric field within the Flory type self-consistent field theory. We consider the influence of electric field on the polymer coil as well as on the polymer globule. We show that when the polymer chain conformation is a coil, application of external electric field leads to its additional swelling. However, when the polymer conformation is a globule, a sufficiently strong field can induce a globule-coil transition. We show that such "field-induced" globule-coil transition at the sufficiently small monomer polarizabilities goes quite smoothly. On the contrary, when the monomer polarizability exceeds a certain threshold value, the globule-coil transition occurs as a dramatic expansion in the regime of first-order phase transition. The developed theoretical model can be applied to predicting polymer globule density change under external electric field in order to provide more efficient processes of polymer functionalization, such as sorption, dyeing, and chemical modification.

Application of small-angle X-ray scattering to the characterization and quantification of the drug transport nanosystem based on the soybean phosphatidylcholine.

Phospholipid transport nanosystem (PTNS) for drug delivery is based on soybean phosphatidylcholine. The morphology of PTNS is investigated by means of small-angle X-ray scattering. The obtained results allow one to answer the key question from the viewpoint of organization of drug incorporation whether the PTNS nanoparticles have a structure of micelles or vesicles. It is demonstrated that PTNS is a vesicular system with an average vesicle radius of 160 ± 2Å.

A new equation of state of a flexible-chain polyelectrolyte solution: Phase equilibria and osmotic pressure in the salt-free case.

We develop a first-principle equation of state of salt-free polyelectrolyte solution in the limit of infinitely long flexible polymer chains in the framework of a field-theoretical formalism beyond the linear Debye-Hueckel theory and predict a liquid-liquid phase separation induced by a strong correlation attraction. As a reference system, we choose a set of two subsystems-charged macromolecules immersed in a structureless oppositely charged background created by counterions (polymer one component plasma) and counterions immersed in oppositely charged background created by polymer chains (hard-core one component plasma). We calculate the excess free energy of polymer one component plasma in the framework of modified random phase approximation, whereas a contribution of charge densities' fluctuations of neutralizing backgrounds we evaluate at the level of Gaussian approximation. We show that our theory is in a very good agreement with the results of Monte Carlo and MD simulations for critical parameters of liquid-liquid phase separation and osmotic pressure in a wide range of monomer concentration above the critical point, respectively.

The local environment of the molecules in water-DMSO mixtures, as seen from computer simulations and Voronoi polyhedra analysis.

Molecular dynamics simulations of water-DMSO mixtures, containing 10, 20, 30, 40, 50, 60, 70, 80, and 90 mol% DMSO, respectively, have been performed on the isothermal-isobaric (N,p,T) ensemble at T = 298 K and at the pressure equal to the experimental vapor pressure at each mixture composition. In addition, simulations of the two neat systems have also been performed for reference. The potential models used in the simulations are known to excellently reproduce the mixing properties of these compounds. The simulation results have been analyzed in detail by means of the Voronoi polyhedra (VP) of the molecules. Distributions of the VP volume and the asphericity parameter as well as that of the radius of the spherical intermolecular voids have been calculated. Detailed analyses of these distributions have revealed that both molecules prefer to be in an environment consisting of both types of molecules, but the affinity of DMSO for mixing with water is clearly stronger than that of water for mixing with DMSO. As a consequence, the dilution of the two neat liquids by the other component has been found to follow different mechanisms: when DMSO is added to neat water small domains of neat-like water persist up to the equimolar composition, whereas no such domains are found when neat DMSO is diluted by water. The observed behaviour is also in line with the fact that the main thermodynamic driving force behind the full miscibility of water and DMSO is the energy change accompanying their mixing, and that the entropy change accompanying this mixing is negative in systems of low and positive in systems of high DMSO mole fractions. Finally, we have found a direct evidence for the existence of strong hydrogen bonded complexes formed by one DMSO and two water molecules, but it has also been shown that these complexes are in equilibrium with single (monomeric) water and DMSO molecules in the mixed systems.