A Model of Acute Peritonitis.

The biological models used in the study of generalized peritonitis can be subdivided into 5 groups (introduction of foreign bodies, cultures of microorganisms, suspensions of feces, chemicals, and mechanical damage to the gastrointestinal tract) or into 4 groups (introduction of foreign bodies, chemicals, bacterial contamination of the abdominal cavity, and combined methods). After analysis of published reports, the most justified classification of methods of peritonitis modelling is based on the type of peritonitis-inducing agent and the administration route and on the nature of peritonitis developing in the abdominal cavity. The choice of the model maximally close reproducing clinical conditions of peritonitis should be based on the specific objectives of the study, focusing on the etiology, pathogenesis, and severity of the disease course, planned measures aimed at eliminating the process, and other factors.

Simulation of Mechanical and Thermal Wounds of Soft Tissues.

Millions of accidental and surgical injuries of soft tissues are registered annually around the world [5]. Untimely and insufficiently effective treatment of wounds in 50-70% leads to the development of purulent-septic infection and the development of septic conditions and fatal outcomes [1-4], which necessitates thorough study of inflammatory and regenerative processes occurring in the injured soft tissues. Various models of mechanical and thermal damage to soft tissues are proposed for studying the inflammatory and reparative processes, for assessing the therapeutic effects and developing new approaches to wound treatment. However, the developed models do not fully meet the requirements of researchers and are not always simple and uniformly reproducible, close to the course of the pathology in humans, and highly reliable. When choosing the model of mechanical and thermal wounds, the experience of other researchers should be taken into consideration due to the need of actualization and improvement of existing models.

[Dynamics of mortality according to the materials of the forensic medical examination bureau of a particular region]. / Dinamika smertnosti po materialam byuro sudebno-meditsinskoi ekspertizy otdel'no vzyatogo regiona.

OBJECTIVE: To show the dynamics of the structure of deaths of the main types of violent and non-violent death on the material of the thanatological department of a separate regional bureau of forensic medical examination. Among the violent causes are considered: mechanical injury, mechanical asphyxia, transport injury, poisoning. Among the nonviolent causes of death the diseases of circulatory system, pneumonia, infectious and oncological pathology have been studied. The period from 2001 to 2020 was investigated. Dynamic changes over a selected period are most clearly demonstrated by the ratio of numerical data to the original 2001 indicators taken as 100%. The data presented objectively reflecting the dynamics of the number and proportion of certain types of death are only the initial stage of the analysis undertaken. The second step should be the determination of the causes of the identified changes that require an integrated approach including medical, demographic and socio-economic data.

Amplification of Relativistic Electron Bunches by Acceleration in Laser Fields.

Direct acceleration of electrons in a coherent, intense light field is revealed by a remarkable increase of the electron number in the MeV energy range. Laser irradiation of thin polymer foils with a peak intensity of ∼1×10^{20} W/cm^{2} releases electron bunches along the laser propagation direction that are postaccelerated in the partly transmitted laser field. They are decoupled from the laser field at high kinetic energies, when a second foil target at an appropriate distance prevents their subsequent deceleration in the declining laser field. The scheme is established with laser pulses of high temporal contrast (10^{10} peak to background ratio) and two ultrathin polymer foils at a distance of 500 µm. 2D particle in cell simulations and an analytical model confirm a significant change of the electron spectral distribution due to the double foil setup, which leads to an amplification of about 3 times of the electron number around a peak at 1 MeV electron energy. The result verifies a theoretical concept of direct electron bunch acceleration in a laser field that is scalable to extreme acceleration potential gradients. This method can be used to enhance the density and energy spread of electron bunches injected into postaccelerator stages of laser driven radiation sources.

Coulomb-driven energy boost of heavy ions for laser-plasma acceleration.

An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19} W/ cm^{2}. Highly charged gold ions with kinetic energies up to >200 MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration.

[Free amino acids and reducing sugars in the freshwater shrimp Gammarus lacustris (Crustacea, Amphipoda) at the initial stage of preparation to winter season].

A peculiarity of amino acid profile of the cold-resistant freshwater shrimp Gammarus lacustris in the beginning of autumn is a high level of ornithine, the second after alanine (17.0 +/- 1.4 and 22.6 +/- 1.4 micromol/ml of homogenate, respectively). The amount of alanine and ornithine accounts for 39.8% of the total pool of free amino acids and together with lysine and leucine - 55%. Free glucose is the major reducing sugar (6.42 +/- 0.78 micromol/ml).

[Congelation of cryoprotective solutions and cryopreservation of fish sperm].

The influence of additional components and the velocity of cooling on the freezing of cryoprotective solutions has been studied using the cryomicroscopy technique. It was shown that additional components and the rate of cooling of cryoprotective medium fundamentally change the ice area of microparticles and the survival of fish spermatozoa during the freezing-thawing procedure.

[Intraoperative ultrasound diagnosis in the removal of intraocular foreign bodies].

The paper provides a rationale and indications for diascleral removal of foreign bodies from the anterior chamber of the eyeball, by intraoperatively using ultrasound study. The clinical material presents 148 cases of diascleral removal of foreign (49 magnetic and 49 amagnetic) bodes impacted into the tunics of the anterior eye without evident opacities of optical media and without signs of endophthalmitis. The paper provides a pathogenetic rationale for the method that is lowly traumatic and highly effective (foreign bodies being removed in 99.9% of cases) due to the high precision of location of a scleral cut in the projection of foreign body bedding owing to intraoperative sound usage. A model clinical case of fragment removal is also shown in the paper. The specific features of criteria for using the method are described, by taking into account the anatomic characteristics of orbital eyeball location.

Energetic proton acceleration and bunch generation by ultraintense laser pulses on the surface of thin plasma targets.

Energetic proton acceleration from concave targets, the front of which were irradiated with 40 fs laser pulses with an intensity of 10(20)W/cm(2), has been studied as a function of the depth of the concave shape. Three kinds of targets, a triangular concave target, a circular concave target and a parabolic concave target are considered. When the depth of the concave shape was varied, the peak proton energy showed a maximum. The underlying mechanism for the existence of a maximum peak proton energy is presented by tracing the proton trajectory. It is concluded that a parabolic concave target is the best, among the targets considered, for accelerating a proton beam, since a proton beam from a parabolic concave target goes through the strongest electric field.

Functional stability of hippocampal slices after treatment with cyclooxygenase inhibitors.

The influence of cyclooxygenase inhibitors on functional stability of hippocampal slices, determined by electrophysiological criteria of recovery after slicing and long-term maintainence of population activity, was studied. Transient (3 min) treatment of slices during slicing with indomethacin (45 microM) or aspirin (0.5 mM) allowed registration of the population responses from the second minute. The activity reached 100% after 15 min incubation and could be registrated for 3 days under conditions of overnight hypothermia. The presence of the same drugs for the entire incubation period had the same effect. The present findings suggest that slicing is a crucial point for triggering of pathological events mediated by cyclooxygenase products and that blockade of cyclooxygenase provides for the further high longterm functional stability of brain slices.

Enhancement of x-ray line emission from plasmas produced by short high-intensity laser double pulses.

Femtosecond laser-produced plasmas are bright ultrafast line x-ray sources potentially suitable for different applications including material science and biology. The conversion efficiency of the laser energy incident onto a solid target into the x-ray emission is significantly enhanced when a laser prepulse precedes the main pulse. The details of x-ray line emission from solid targets irradiated by a pair of ultrashort laser pulses are investigated both theoretically and experimentally. Insight into spatial and temporal characteristics of the line x-ray source is provided by numerical simulations and a simplified analytical model. Optimal time separation of the laser pulses is searched for in order to reach the maximum conversion of laser energy into the emission of selected x-ray lines. We deduced how the optimal pulse separation scales with laser and target parameters.

Scattered light diagnostics of overdense plasma cavity in solid targets irradiated by an ultraintense laser pulse.

The light scattered backward from a target illuminated by ultraintense laser pulses carries important information about the nonlinear laser-plasma interaction. We analyze the usefulness of this information by plasma corona analysis with the help of an analytical model we developed, and particle-in-cell simulation. The spectrum of scattered light is shown to be shifted, to be broadened, and to be modulated, in comparison with the initial laser spectrum, and the spectral shift is an indicator of laser pulse contrast ratio.

Electron bunch trapping and compression by an intense focused pulse laser.

A focused short-pulse laser of TEM (1,0)+TEM (0,1) mode has two intensity peaks in the radial direction, so that the transverse ponderomotive force may trap electrons between the two peaks. At the same time the longitudinal ponderomotive force may accelerate electrons at the head of the laser pulse, when the laser is focused. When the electrons move to the laser tail, the laser may diverge and the electron deceleration becomes relatively weak. Our numerical analyses demonstrate that electrons are trapped well by the laser potential well, and that at the same time the acceleration by the longitudinal ponderomotive force induces the electron bunch compression. This trapping and compression mechanism is unique: the electron bunch can be compressed to the scale of the laser pulse length.

Waveguide propagation of intense electromagnetic radiation in slightly inhomogeneous nonlinear media.

The propagation of self-localizing beams of electromagnetic waves in the form of nonlinear waveguides in a slightly inhomogeneous medium is studied analytically and numerically. The trajectories of the axial ray are studied as a function of its direction and the field strength at the initial point on the basis of a nonlinear scalar Helmholtz equation. Analytic expressions are derived. The longitudinal refractive index, the field intensity, and the waveguide radius are plotted as functions of the instantaneous position of the point on the axial ray. Deep penetration of the beam into the opaque region and the position of the screening surface are studied as functions of the parameters of the beam and the medium. A steady-state 3D problem is analyzed for a power-law nonlinearity with an arbitrary power. A 2D problem is analyzed for the case of a ponderomotive nonlinearity with saturation.

[Crystallization of aqueous solutions of cryoprotectors from Atlantic cod and lake Gammarus]. / Kristallizatsiia vodnykh rastvoov krioprotektorov atlanticheskoi treski i ozernogo gammarusa.

A comparative analysis of two types of cryoprotectants, antifreeze glycoproteins from Atlantic cod (Gadus morhua) and carbohydrates from hemolymph of amphypoid crustacean (Gammarus lacustris) has been performed. Both glycoprotein and carbohydrate antifreezes effectively decreased the freezing point of water solutions and diminished the size of ice crystals formed. Noncolligative and colligative mechanisms of action are characteristic correspondingly for glycoproteins and carbohydrates.

[The use of various models of biosynthesis kinetics]. / O vozmozhnosti ispol'zovaniia razlichnykh modelei kinetiki biosinteza.

The available models of the microorganism growth kinetics are analyzed. The possibility of application of the Monod model is studied. It is shown that these models do not permit describing adequately the experimental data at different initial concentrations of biomass and substrate that vary in a wide range. The calculations of the static modes of operation of biochemical react ors differ greatly.

[Forecasting of biocenosis quantity in the open system with a finite difference model]. / Prognozirovanie chislennosti biotsenoza v otkrytoi sisteme s pomoshch'iu konechno-raznostnoi modeli s zapazdyvaniem.

A simple mathematical model for the dynamics of biocenosis in an open system was worked out. The model is based on the finite-difference presentation of experimental data. It also takes into account the past history of population development. The testing of the model proved its ability to forecast the density of populations in open systems.

[Long-term morphofunctional preservation of guinea pig hippocampal slices following short-term treatment with cyclooxygenase inhibitors]. / Dlitel'naia morfofunktsional'naia sokhrannost' srezov gippokampa morskoi svinki posle kratkoi obrabotki ingibitorami tsiklooksigenaz.

Hippocampal slices treated with cyclooxygenase inhibitor indomethacin for three min during the sectioning (45 min) or aspirin (0.5 min) in long term (up to 5 days) preservation in periodic nocturnal hypothermia were studied morphofunctionally using light microscopy and electrophysiological registration of induced population responses of area CAI to stimulation of Schaffers collaterals. Structural disorders were revealed in control slices as early as the third hour of incubation and they were destroyed following the first hypothermal challenge (24 hrs following preparation). The structure in slices treated with blockers remained more stable as compared to control ones and the activity was registered until d 3 (aspirin) and 5 (indomethacin). Morphological changes were not immediately, followed by electric activity decline. On the whole it may be suggested that essential viability increase occurred due to destructive processes inhibition mediated by short living cyclooxygenase metabolites.

[Use of enzyme-antibody immune complexes in serological analysis]. / Primenenie immunnykh kompleksov fermenta--antitelo v serologicheskom analize.

In model experiments with simulation of rabbit immune response to mouse IgG and antibody production in echinococcosis patients the indirect enzyme-linked immunosorbent assay has been several times more sensitive with peroxidase-antiperoxidase and catalase-anticatalase complexes than with enzyme-antiglobulin chemical conjugates. The immune complexes have been found to retain their activity for 6 months and longer.

[Testaceans (Protozoa: Testacea) in quaternary permafrost sediments of Bykovsky Peninsula, arctic Yakutia]. / Rakovinnye ameby (Protozoa: Testacea) v chetvertichnykh mnogoletnemerzlykh otlozheniiakh poluostrova Bykovskii, arkticheskaia Iakutiia.

The results of the first protozoological study in terms of paleoecology of long-term sediments and buried soils formed in the cryolite zone of northeastern Siberia are discussed. The data on testaceans (Protozoa: Testacea) inhabiting various sites of Bykovsky Peninsula, Laptev Sea coast near estuary of Lena, within the last 53,000 years (late Pleistocene and Holocene).