Energy-optimal steering of transitions through a fractal basin boundary.

We study fluctuational transitions in a discrete dy- namical system having two co-existing attractors in phase space, separated by a fractal basin boundary. It is shown that transitions occur via a unique ac- cessible point on the boundary. The complicated structure of the paths inside the fractal boundary is determined by a hierarchy of homoclinic original sad- dles. By exploiting an analogy between the control problem and the concept of an optimal fluctuational path, we identify the optimal deterministic control function as being equivalent to the optimal fluctu- ational force obtained from a numerical analysis of the fluctuational transitions between two states

Decay of the turbulent cascade of capillary waves on the charged surface of liquid hyrdrogen.

We study the free decay of capillary turbulence on the charged surface of liquid hydrogen. We find that the decay begins from the high frequency spectral domains of the surface oscillations and is of a quasi-adiabatic character. The characteristic relaxation time of the whole turbulent cascade is close to the viscous damping time for capillary waves of frequency equal to the driving frequency

Effects of enzymatically depolymerised fucoidan on effector functions of innate and adaptive immunity cells

The use of sulfated polysaccharides (fucoidans) as active pharmaceutical ingredients or adjuvants poses the challenge of obtaining structurally characterised and homogeneous samples or their oligomeric fractions maintaining high biological activity. The authors obtained a highly purified enzymatic hydrolysate of fucoidan from the brown alga Fucus evanescens and compared its biological activity with that of a native sample. The aim of the study was to compare, in vitro and in vivo, the effects of depolymerised fucoidan from the brown alga F. evanescens and native fucoidan on the effector functions of innate and adaptive immunity cells loaded with ovalbumin (OVA). Materials and methods: the effects of the fucoidan samples (depolymerised and native) on the expression of the main immunophenotypic markers by innate and adaptive immunity cells (neutrophils, monocytes, natural killers, and lymphocytes) were studied in vitro using flow cytometry. The levels of serum OVA-specific antibodies (IgG, IgG1, IgG2а) and cytokines (IFN-γ, IL-2, IL-10, IL-12) were studied in vivo using BALB/c mice immunised with OVA. The statistical analysis of the data obtained was performed using the Statistica 10 software package. Results: in vitro, both fucoidan samples altered the expression of the main immunophenotypic markers by innate and adaptive immunity cells, indicating their activation. In vivo, mice treated with the fucoidan samples demonstrated an increase in the levels of OVA-specific antibodies (IgG, IgG1 and IgG2a) and in the production of cytokines (IFN-γ, IL-2, IL-10). Conclusions: the effects of enzymatically depolymerised fucoidan on functional activity of innate and adaptive immunity cells are comparable to those of native fucoidan. The findings indicate the possibility of using enzymatic hydrolysis products of fucoidan as adjuvants for a wide range of prophylactic and therapeutic vaccines

DETECTION OF CAUSATIVE AGENTS OF TICK-BORNE INFECTIONS BY POLYMERASE CHAIN REACTION ASSAY CARRIED OUT AS A PART OF CLINICAL STUDIES IN THE “REPUBLICAN CLINICAL INFECTIOUS DISEASES HOSPITAL” OF ULAN-UDE

The article is devoted to the study of vector-borne pathogens circulating in the Republic of Buryatia. The authors have carried out  identification of the genetic material of tick-borne encephalitis virus,  Borrellia burgdorferi, Borrellia miуamotoi, Coxiella burnetii and  Rickettsia sibirica in various samples of biological material. The  object of the study were whole blood, leukocyte fraction and blood  serum of patients admitted to the hospital in a state of fever that  occurred after sucking of the tick, as well as mites brought by the  population. A detailed analysis of the data showed that 11.7 % (9  out of 70) of the clinical material samples and 17.8 % (50 out of  281) of the tick samples had genetic markers of tick-borne  pathogens. In the material from the patients, the RNA of tick-borne  encephalitis virus was most often determined, and in the DNA of  Borrellia burgdorferi mites. In addition, the authors first confirmed  the etiologic role of Borrellia miуamotoi in the development of cases  of Lyme disease in the Republic. An unexpected finding was the  detection of Coxiella burnetii DNA in ticks and in clinical material. In  the Republic of Buryatia Q-fever was detected by laboratory  diagnostics for the first time. This fact confirms the circulation of this pathogen in the region. In this regard, the authors conducted a  retrospective analysis of the medical histories of patients who were found to have genetic markers of Q-fever

Incresing the efficiency of heat and mass exchange in an improved rotary film evaporator for concentration of fruit-andberry purre

An improved model of a rotary film evaporator with a cutting blade having a reflective surface and equipped with an autonomous heating system which is fed by a power supply from Peltier elements. The reflective surface of the advanced cutting blade had an area of 0.06 m2 and was heated by a flexible film resistive electric heater of radiating type with a ~15...20 W power supply. This solution provides additional heating and mixing and helps to capture the cut-off layer of puree while reducing the useful surface of the working chamber by 7 %. Most evaporators have a low heat transfer coefficient reducing the energy content of the process and final quality of the product. The heat exchange efficiency can be increased by improving the design of the film-forming element of the rotary film evaporator. The use of the proposed cutting blade with a reflective surface enables an increase in the heat transfer coefficient by approximately 20 % compared to the basic rectangular blade design. When comparing the calculated data, it can be concluded that the main indicator of resource efficiency, namely specific energy consumption for heating a unit volume of product in the RFE amounts to 408 kJ/kg compared to 1,019 kJ/kg with the basic vacuum evaporator which means a 1.97 times consumption reduction. The duration of heat treatment in the RFE is 60 s compared to 1 h in the basic VE which shows a significant reduction of raw material exposure to high temperatures. The obtained data show the effectiveness of engineering and technological solutions. The engineering and technological component of any heat and mass exchange processes, in particular the concentration of fruit-and-berry raw materials, is the main component in the production of semi-finished food products of a high degree of readiness

Влияние ферментативно деполимеризованного фукоидана на эффекторные функции клеток врожденного и адаптивного иммунитета

The use of sulfated polysaccharides (fucoidans) as active pharmaceutical ingredients or adjuvants poses the challenge of obtaining structurally characterised and homogeneous samples or their oligomeric fractions maintaining high biological activity. The authors obtained a highly purified enzymatic hydrolysate of fucoidan from the brown alga Fucus evanescens and compared its biological activity with that of a native sample. The aim of the study was to compare, in vitro and in vivo, the effects of depolymerised fucoidan from the brown alga F. evanescens and native fucoidan on the effector functions of innate and adaptive immunity cells loaded with ovalbumin (OVA). Materials and methods: the effects of the fucoidan samples (depolymerised and native) on the expression of the main immunophenotypic markers by innate and adaptive immunity cells (neutrophils, monocytes, natural killers, and lymphocytes) were studied in vitro using flow cytometry. The levels of serum OVA-specific antibodies (IgG, IgG1, IgG2а) and cytokines (IFN-γ, IL-2, IL-10, IL-12) were studied in vivo using BALB/c mice immunised with OVA. The statistical analysis of the data obtained was performed using the Statistica 10 software package. Results: in vitro, both fucoidan samples altered the expression of the main immunophenotypic markers by innate and adaptive immunity cells, indicating their activation. In vivo, mice treated with the fucoidan samples demonstrated an increase in the levels of OVA-specific antibodies (IgG, IgG1 and IgG2a) and in the production of cytokines (IFN-γ, IL-2, IL-10). Conclusions: the effects of enzymatically depolymerised fucoidan on functional activity of innate and adaptive immunity cells are comparable to those of native fucoidan. The findings indicate the possibility of using enzymatic hydrolysis products of fucoidan as adjuvants for a wide range of prophylactic and therapeutic vaccines.Использование сульфатированных полисахаридов (фукоиданов) в качестве фармацевтических субстанций или адъювантов связано с решением задачи по получению структурно охарактеризованных и однородных образцов или их олигомерных фракций, сохраняющих высокую биологическую активность. Нами получен высокоочищенный продукт ферментативного гидролиза фукоидана из бурой водоросли Fucus evanescens и дана оценка биологической активности полученного продукта в сравнении с нативным фукоиданом. Цель работы: изучение влияния ферментативно деполимеризованного образца фукоидана из бурой водоросли F. evanescens на эффекторные функции клеток врожденного и адаптивного иммунитета in vitro и in vivo в условиях антигенной нагрузки овальбумином (ОВА) в сравнении с нативным фукоиданом. Материалы и методы: для оценки влияния образцов фукоиданов (ферментативно деполимеризованного и нативного) in vitro на уровень экспрессии основных иммунофенотипических маркеров клеток врожденного и адаптивного иммунитета (нейтрофилов, натуральных киллеров, моноцитов, лимфоцитов) применяли методы проточной цитометрии. В экспериментах in vivo в сыворотке крови мышей линии BALB/c, иммунизированных ОВА, исследовали уровень специфических антител IgG, IgG1, IgG2а и цитокинов (IFN-γ, IL-2, IL-10, IL-12). Статистическую обработку полученных данных проводили с помощью пакета программы Statistica 10. Результаты: под влиянием обоих образцов фукоиданов in vitro выявлены изменения уровня экспрессии основных иммунофенотипических маркеров клеток врожденного и адаптивного иммунитета, свидетельствующие об их активации. В условиях in vivo под действием образцов фукоиданов наблюдалось увеличение уровня ОВА-специфических антител (IgG, IgG1, IgG2a) и продукции цитокинов (IFN-γ, IL-2, IL-10). Выводы: показана активация образцом ферментативно деполимеризованного фукоидана врожденного и адаптивного иммунитета, которая не уступает действию нативного образца фукоидана, что определяет возможность его применения в качестве адъюванта для широкого спектра профилактических и терапевтических вакцин

Accommodating a Non-Conservative Internal Mutation by WaterMediated Hydrogen-Bonding Between β-Sheet Strands: A Comparison of Human and Rat Type B (Mitochondrial) Cytochrome b5

Mammalian type B (mitochondrial) cytochromes b5 exhibit greater amino acid sequence diversity than their type A (microsomal) counterparts, as exemplified by the type B proteins from human (hCYB5B) and rat (rCYB5B). The comparison of X-ray crystal structures of hCYB5B and rCYB5B reported herein reveals a striking difference in packing involving the five-stranded β-sheet, attributable to fully buried residue 21 in strand β4. The greater bulk of Leu21 in hCYB5B in comparison to Thr21 in rCYB5B results in a substantial displacement of the first two residues in β5, and consequent loss of two of the three hydrogen bonds between β5 and β4. Hydrogen-bonding between the residues is instead mediated by two well-ordered, fully buried water molecules. In a 10 ns molecular dynamics simulation, one of the buried water molecules in the hCYB5B structure exchanged readily with solvent via intermediates having three water molecules sandwiched between β4 and β5. When the buried water molecules were removed prior to a second 10 ns simulation, β4 and β5 formed persistent hydrogen bonds identical to those in rCYB5B, but the Leu21 side chain was forced to adopt a rarely observed conformation. Despite the apparently greater ease of water access to the interior of hCYB5B than of rCYB5B suggested by these observations, the two proteins exhibit virtually identical stability, dynamic and redox properties. The results provide new insight into the factors stabilizing the cytochrome b5 fold

Noise-induced escape through a fractal basin boundary

We study noise-induced escape within a discrete dynamical system that has two co-existing chaotic attractors in phase space separated by a locally disconnected fractal basin boundary. It is shown that escape occurs via a unique accessible point on the fractal boundary. The structure of escape paths is determined by the original saddles forming the homoclinic structure of the system and by their hierarchical interrelations

Computational modeling of paroxysmal depolarization shifts in neurons induced by the glutamate release from astrocytes

Recent experimental studies have shown that astrocytes respond to external stimuli with a transient increase of the intracellular calcium concentration or can exhibit self-sustained spontaneous activity. Both evoked and spontaneous astrocytic calcium oscillations are accompanied by exocytosis of glutamate caged in astrocytes leading to paroxysmal depolarization shifts (PDS) in neighboring neurons. Here, we present a simple mathematical model of the interaction between astrocytes and neurons that is able to numerically reproduce the experimental results concerning the initiation of the PDS. The timing of glutamate release from the astrocyte is studied by means of a combined modeling of a vesicle cycle and the dynamics of SNARE-proteins. The neuronal slow inward currents (SICs), induced by the astrocytic glutamate and leading to PDS, are modeled via the activation of presynaptic glutamate receptors. The dependence of the bidirectional communication between neurons and astrocytes on the concentration of glutamate transporters is analyzed, as well. Our numerical results are in line with experimental findings showing that astrocyte can induce synchronous PDSs in neighboring neurons, resulting in a transient synchronous spiking activity

Fluctuational transitions across different kinds of fractal basin boundaries.

We study fluctuational transitions in discrete and continuous dynamical systems that have two coexisting attractors in phase space, separated by a fractal basin boundary which may be either locally disconnected or locally connected. Theoretical and numerical evidence is given to show that, in each case, the transition occurs via a unique accessible point on the boundary, both in discrete systems and in flows. The complicated structure of the escape paths inside the locally disconnected fractal basin boundary is determined by a hierarchy of homoclinic points. The interrelation between the mechanism of transitions and the hierarchy is illustrated by consideration of fluctuational transitions in dynamical systems demonstrating "fractal-fractal" basin boundary metamorphosis at some value of a control parameter. The most probable escape path from an attractor, which can be either regular or chaotic, is found for each type of boundary using both statistical analysis of fluctuational trajectories and the Hamiltonian theory of fluctuations