


Vol 63, No 9 (2018)
- Year: 2018
- Articles: 24
- URL: https://journal-vniispk.ru/1063-7842/issue/view/12574
Physical Approaches and Problems of Data Interpretation in the Life Sciences
Interrelation of Absorption Spectra of Plant Pigments and LED Lighting with Different Spectral Compositions
Abstract
Absorption spectra of pigments derived from the plants that were illuminated by light with different spectral composition during their growth are presented. The role of the spectrum of LED lighting in the life of plants has been estimated, and its influence on pigment absorption has been noted. It has been recommended to use a full range of lighting in the range of 400–700 nm with the domination of the red component when growing oats in protected ground. It has been found that the recording of absorption spectra of pigments allows the monitoring of the influence of lighting on the processes of plant growth and development. It has been assumed that the use of sources with a controlled spectrum in a greenhouse will allow directed influence on the nature of biochemical reactions occurring in plants during their development: photosynthesis and photomorphogenesis.



Biologically Active Hybrid Nanosystems Based on Zero-Valent Selenium Nanoparticles, Biocompatible Polymers, and Polyelectrolitic Complex
Abstract
The molecular-conformal, morphological, and kinetic characteristics of selenium-containing nanosystems (NSs) based of biocompatible polymer matrices of different origins modified Se0 nanoparticles for the Se0 : polymer mass ratio ν = 0.1 have been analyzed using static and dynamic light scattering methods, UV spectroscopy, flow birefringence, and atomic force and transmission electron microscopies. We have determined the rate constants for the formation of selenium-containing NSs, the size characteristics of the corresponding nanostructures, as well as their shape, molecular mass, and density. It is found that isolated dense spherical polymolecular selenium-containing nanostructures are formed in the aqueous solution. Our results can be used as the physicochemical foundation for the modification of polymer materials with clearly manifested physiological activity by biogenic elements in the zero-valent form.



A New Method for Production of the Sr-82 Generator Radionuclide and Other Medical Radionuclides
Abstract
A cyclotron (C-80) designed to produce protons with an energy of 40–80 MeV and beam intensity of 100–200 μA has been launched at the Petersburg Nuclear Physics Institute, National Research Center Kurchatov Institute. The main task of C-80 is the production of a wide range of medical radionuclides for diagnosis and therapy. A complex named Radioactive Isotopes on the C-80 Cyclotron (RIC-80) and intended to function on the C-80 beam was developed for this purpose. A brief description of the RIC-80 complex is given, and the results of the use of new methods and studies of target devices for the production of the generator radioisotope 82Sr; 223Ra, 224Ra, and 225Ac radioisotopes that undergo alpha-decay; 67Cu; and other medical radionuclides are presented. The use of a mass separator in the “on-line” mode to obtain ion beams of high-purity radioisotopes is a distinctive feature of the complex used in the project, and it is especially important for medical applications.



A Model of Intermittent Ballistic-Brownian Particle Transport and Its Asymptotic Approximation
Abstract
A mean-field model of intermittent transport of particles, molecules or organelles is proposed. A particle may be in one of two phases: the first is a ballistic (active) phase, when the particle runs with constant velocity in some direction, and the second is a Brownian (passive) phase, when the particle diffuses freely. The particle can instantly change the phase of motion. The distribution of the duration of the passive phase (the free path distribution) is exponential, while that of the active phase is arbitrary. In the case that transitions between the phases are very frequent an approximation to the model is derived. An example is given which shows that the use of the exponential distribution of free paths, when it is actually non-exponential, may lead to significant errors in solutions.



Simulation of the Stationary and Nonstationary Charge Transfer Conditions in a Uniform Holstein Chain Placed in Constant Electric Field
Abstract
The charge transfer in a Holstein molecular chain placed in a uniform electric field has been numerically simulated. It has been shown that for given parameters of the chain, a charge placed in a constant electric field may uniformly travel very large distances (several hundred thousand sites). The charge may move with a constant velocity if the field strength is low. With an increase in the field strength, the charge starts oscillating (Bloch oscillations). Good agreement has been shown between the theoretical and numerical field dependences of the charge constant velocity.



The Electron-Conformational Model of Ryanodine Receptors of the Heart Cell
Abstract
The main ideas of an electron-conformational (EC) model of ligand-activated ryanodine channels (RyR) that reduces many degrees of freedom of this gigantic nanoscopic molecular complex to two so-called electron and conformational degrees of freedom are presented. In the toy model, the conformational potential or energy profile of the RyR channel represents two branches that describe the dependence of energy on the conformational coordinate (reaction coordinate) in the initial and ligand-activated states, respectively. A model extension that takes into account both the tetrameric structure of the RyR channel and additional (orthogonal) rotational conformational mode has been considered. The EC model has been demonstrated to give a biophysical basis to the traditional phenomenological model of Markov chains. To demonstrate the possibilities of the EC model, we refer to examples of model description of the dynamics of isolated RyR channels and clusters of RyR channels in release units of the heart cell.



Novel Regulatory System in Plants and the Necessity of a Breeding Phytotron in the Russian Federation
Abstract
A novel plant epigenetic regulatory system is reported. This is a change in product spectra of genes determining a productivity trait caused by a change in a limiting factor of the environment. Based on this discovery, the Theory of Ecogenetic Organization of Plant Quantitative Traits (TEGOPQT) was elaborated over the period from 1984 to 2014. The Theory gave rise to 24 prognostic corollaries and 10 know-hows. They are able to increase sharply the effectiveness of plant breeding aimed at higher yields. The prerequisite of this success is a creation of a priority breeding phytotron in the Russian Federation. The paper lists the necessary biophysical instruments and other devices that are needed to equip the growth chambers of the phytotron.



Polarized Fluorescence in Indole under Two-Photon Excitation by Femtosecond Laser Pulses
Abstract
We have analyzed the decay of fluorescence intensity in indole dissolved in propylene glycol under two-photon excitation by linearly and circularly polarized femtosecond laser pulses in the wavelength range 475–510 nm. The dependences of fluorescence intensity I0, anisotropy r, and parameter Ω on the excitation energy have been determined and analyzed. In particular, a nonmonotonic behavior of I0 indicating the increase of indole excited state density in the excitation energy range above 5.1 eV and the anisotropy sign reversal due to the variation of the symmetry of indole vibronic states have been observed and interpreted theoretically.



Spectral Characteristics of the DMEM Cell-Culture Medium
Abstract
Spectral characteristics of luminescence of the DMEM cell-culture medium are studied. The luminescence spectrum of the medium is determined in the visible and near-IR spectral ranges at wavelengths of up to 1350 nm under excitation at 405 and 660 nm. The lifetimes of excited states of the medium are determined, and the absence of singlet oxygen phosphorescence at about 1270 nm is demonstrated.



Viability of Different Types of Cells Cultivated on the Surface of Medical Electret
Abstract
The effect of the electric field of a medical electret on the basis of tantalum pentoxide (Ta2O5) on the viability of human fibroblasts, multipotent mesenchymal stromal bone marrow cells, osteocytes, and chondrocytes cultivated on the surface of tantalum orthopedic implants with an electret coating was studied in vitro. Using the methods of photocolorimetic analysis and scanning electron microscopy, difference in the metabolic activity and cell morphology, in the character of the cell attachment to the implants and distribution by their surface, associated with the value and character of the electric charge distribution on the surface of these implants and the type of cellular test systems, were detected. Unclear mechanisms of the effect of the electric field of medical electrets on the functional activity of different types of the organism cell and tissues dictate the need for further experimental developments and fundamental studies in this field.



Development of Process Technologies, Diagnostic Methods, and Functional Materials and Structures
Non-Hydrostatic Pressure-Induced Phase Transitions in Self-Assembled Diphenylalanine Microtubes
Abstract
The structural phase transitions in diphenylalanine microtubes caused by an increase in the non-hydrostatic pressure have been examined. Raman scattering investigations have been carried out and the results obtained have been interpreted and analyzed. Spectral variations in the ranges of phenyl ring vibrations and high-frequency oscillations of NH and CH groups have been analyzed. Under pressures of up to 9.8 GPa, four spectral anomalies indicative of the occurrence of phase transitions have been observed. The transitions under pressures of 1.7 and 4 GPa are shown to be reversible. The transition at 5.7 GPa is accompanied by partial sample amorphization.



Investigation of Toxic Effect and Penetration into Cells of Monodisperse Spherical Composite Particles Based on Mesoporous Silica
Abstract
Сomposite particles based on monodisperse spherical mesoporous silica particles (MSMSPs) are synthesized by noncovalent binding of organic active components (propidium iodide fluorescent dye and Radakchlorin photosensitizer) from aqueous solutions. Hybrid particles with a core–shell structure are synthesized, which are MSMSPs filled with Fe3O4 and coated with mesoporous silica, the internal surface of which is modified by Fluorescein isothiocyanate (FITC) fluorescence dye by means of chemisorption. The toxicity and penetration of the obtained particles into the cells of the HeLa and K-562 cell lines were studied. The effective photodynamic action of MSMSPs containing Radachlorin in mesopores is demonstrated, which indicates the promise of using the synthesized composite particles for medical purposes.



The Mechanical Properties of Chitosan Fibers Obtained in Different Spinning Conditions by Coagulation Method
Abstract
The chitosan fibers have been obtained by coagulation method from an aqueous solution of 2% acetic acid into an ethanol–alkaline mixture. The influence of the chitosan molecular mass, the polymer solution feed rate, and the stretching ratio on the mechanical properties of the obtained filaments has been investigated. It is found that the viscosity of the chitosan solution depends on the chitosan molecular mass: with increasing molecular mass, the viscosity of the solution increases and, hence, the concentration of chitosan in the solution required for processing decreases. The optimal parameters of the spinning process have been determined. Polyfilament fibers with different diameters of elementary filaments and their number have been obtained.



Formation of Polyacrylamide and PEGDA Hydrogel Particles in a Microfluidic Flow Focusing Droplet Generator
Abstract
Monodisperse polymeric particles have great potential in biomedical and physical applications. Modern high-throughput droplet microfluidic technologies make it possible to produce monodisperse water-in-oil macroemulsions with desired properties. Polymerization in a macroemulsion transforms it to a suspension of microparticles. These particles may be viewed as containers for targeted delivery of drugs and also as bioink for 3D printing of tissues and organs. Conditions for formation of PEGDA and polyacrylamide particles using a microfluidic flow-focusing emulsion generator have been studied. Manufactured microparticles have been characterized by their geometrical sizes and mechanical properties. In addition, the diffusion escape of small molecules from microparticles has been studied using Rhodamine B fluorescent dye.



Self-Organization of a Bioactive Nanostructured Oxide Layer at the Surface of Sintered Titanium Sponge Powder Subjected to Electrochemical Anodization
Abstract
Self-ordered nanoporous/nanotubular oxide films are prepared on the surface of porous powder materials of a titanium sponge by electrochemical anodization. By using scanning electron and atomic force microscopies, we establish that anodization of sintered powder of a titanium sponge in an electrolyte containing H2SO4 (10%) and HF (0.15%) yields an X-ray amorphous TiO2 film with a thickness of 250–350 nm and a regular pattern of nanopores and nanotubes with diameters of 30 to 70 nm. Our results confirm that the described method for surface modification of sintered powders of a titanium sponge holds promise in manufacturing bioactive implants.



Spectrophotometric Evaluation of L-Lysine Concentrations in Water–Organic Solutions
Abstract
In this work, the conditions of spectrophotometric evaluation of the ninhydrin assay for L-lysine in a water dimethyl sulfoxide solution were investigated. The absorption spectrum of the L-lysine–ninhydrin reaction product exhibited two maxima at 420 and 500 nm. It was shown that pH of the reaction medium affected the intensity of the product color. The stability of the ninhydrin reaction products was the highest at pH 8–9. The phase proportion of the water–organic solution had little effect on the optical density of the product. The absorption spectra of the ninhydrin reaction products of L-lysine derivatives: Nα-boc-lysine and Nε-z-lysine, indicated that it was the α amino group of lysine that participated in the reaction.



Immobilization of Photoditazine on Vaterite Porous Particles and Analysis of the System Stability in Model Media
Abstract
In this paper, we present the results on immobilization of Photoditazine, the photosensitizer of the second generation, on vaterite (metastable modification of calcium carbonate) porous particles of two different sizes. The adsorption efficiency is found to be 3.0 and 3.2 wt % Photoditazine on vaterite particles with average diameters of 5 and 0.5 μm, respectively. The curves of Photoditazine desorption from vaterite particles are determined depending on the composition of the dispersion medium (water and bovine serum albumin solution). It is found that vaterite particles in water are subjected to recrystallization in accordance with the dissolution–precipitation mechanism. The presence of albumin molecules at a physiological concentration allows stabilizing metastable vaterite particles of micron and submicron size for at least 17 days.



Porous Silicon as a Nanomaterial for Disperse Transport Systems of Targeted Drug Delivery to the Inner Ear
Abstract
The samples of porous silicon (por-Si) particles in three size ranges (60–80, 250–300, and 500–600 nm) are obtained by electrochemical anodic etching of single-crystal silicon in an electrolyte based on an HF solution, followed by a change in the modes of ultrasonic treatment and homogenization. A complex characterization of particles was carried out by scanning electron microscopy, photon cross-correlation spectroscopy, and X-ray photoelectron spectroscopy. In vitro biocompatibility models using unicellular organisms of infusoria Paramecium caudatum Keln are applied to demonstrate the low toxicity of the samples at concentrations used for intravenous administration. The systemic in vivo biodistribution was studied for the por-Si 60–80 nm sample using adult Wistar rats. Introduced nanoobjects are found in the liver and heart tissues without significant changes in shape or size and predominantly in the oxidized state. Possibilities of using por-Si samples as matrices for transporting pharmaceuticals with intravenous administration are studied by assessing the intensity of the ototropic effect of gentamicin. An objective audiologic method for studying the amplitude of otoacoustic emission revealed the largest otodepressive effect of gentamicin when submicrometer-sized por-Si particles (500–600 nm) was used as a disperse system for drug delivery. Thus, modifications of the conditions for the synthesis of por-Si nanoparticles are promising directions in obtaining physicochemical parameters of transport particles that are optimal for specific tasks of targeted drug delivery.



Instrument Development and Devices for Practical Applications
Microchip Devices for Nucleic Acid Amplification
Abstract
Basic requirements for microchip devices used in nucleic acid amplification by means of a polymerase chain reaction (PCR), as well as in their isothermal amplification, are considered, and the results of testing the devices made of various materials are reported. Tests involved detecting a small amount of nucleic acid molecules in a sample by the colony PCR technique. The uniformity of the molecular colony distribution over the reaction chamber of the device has been quantitatively estimated. The application potential of the microchips for molecular diagnostics is discussed.



Method for the Search for the Size Standard Peaks in Fragment Analysis of DNA
Abstract
Fragment analysis of DNA by the capillary gel-electrophoresis method is an effective tool for studying the DNA structure, which has a large number of applications (in particular, for genetic expertise of breeds and breed samples of a number of important crops). Fragment analysis of DNA is carried out in several stages. The stage of processing of the results of investigations includes the procedure of detection of peaks for standard DNA fragments. We list the features of the spectrum of the DNA fragment distribution, which necessitate the development of a new method for detecting peaks of a standard. We propose a method for their search based on comparison of the aggregate of standard lengths of DNA fragments and spectral peaks and describe the algorithm for implementing this method. We also consider in detail the critical stage of the algorithm, i.e., the choice of the threshold for the procedure of detection of peaks in the spectrum. The advantages and disadvantages of the method are enumerated and the results of testing are considered.



Screening of the Protective Actions under the Laser Irradiation of Bio-Objects: Experimental Results and Physical Model
Abstract
The screening of protective radiations that occur during laser radiation of biological tissues have been experimentally studied. The metallic and dielectric screens with different shape have been used for screening. The physical model of generation of the secondary radiation that generates the protective effects, which lead to a substantial increase in the environmental resistance of living organisms placed nearby, has been suggested. It has been assumed that this radiation is mainly concentrated in the frequency range lower than 10 GHz.



Imaging in Diagnostic Nuclear Medicine
Abstract
Single-photon emission computed tomography (SPECT) and positron emission tomography (PET) are modern methods for visualization in diagnostic nuclear medicine. SPECT is known as a workhorse in cardiology, and PET is the gold standard in oncology. The development of nuclear medicine is provided by cooperation of physicists, mathematicians, biologists, medical doctors, and radio-chemists. In spite of extensive clinical applications, several problems may lead to false diagnoses. In particular, the correction of attenuation of gamma radiation in human organs must be taken into account. For interpretation and evaluation of such an effect on the clinical results, we perform physico-mathematical simulation of the SPECT diagnostics in cardiology in the absence and presence of the correction of attenuation. A brief review of the state-of-the art is presented. The simulation employs the first Russian anthropomorphic mathematical phantom that describes the distribution of radio-pharmacological agent (99m Tc-methoxyisobutylisonitrile) in chest organs of a typical male patient. A model for calculation of raw images is developed with allowance for attenuation of radiation in biological tissues and the effect of collimator and detector. The results of the proposed models and calculated images are compared with clinical images obtained at the Meshalkin Institute of Circulation Pathology (Novosibirsk) and Myasnikov Institute of Clinical Cardiology (Moscow). Statistical algorithms are developed for the solution of the inverse problem of image reconstruction based on the entropy principle. The clinical and physico-mathematical approaches are compared in the evaluation of the effect of correction on the quality of reconstructed images of the left ventricle of myocardium.



The Single Cells and Cell Populations Viability Estimation in vitro by the Time-Domain Impedance Spectroscopy
Abstract
In the present study, we investigate the sensitivity and applicability of the time-domain electrical impedance spectroscopy (EIS) techniques, namely Fourier-EIS and adaptive filtering based EIS (AF-EIS), for studying cells' populations and single living cells in natural physiological environment in vitro. Using ultra-violet radiation for decreasing cell life-span we demonstrate the possibility to distinguish the living cells' population from the dead cells by both Fourier-EIS and AF-EIS. However, determining the viability of the single cell requires significant sensitivity, which is inaccessible with the conventional Fourier-EIS contrary to AF-EIS. The latter result stems from the high noise immunity of the AF-EIS, which also makes it possible to provide the measurements using the safe for cells 15-mV excitation voltage and 10–100 nA current response. The developed single-cell AF-EIS approach opens a direct roadmap for creating accurate, robust, and easy to implement toxin and radiation hazard sensors with the living cell as an acting element and proposes a solution for actual ecological and healthcare problems.



InAsSb Diode Optical Pairs for Real-Time Carbon Dioxide Sensors
Abstract
Efficiencies of optical pairs consisting of fast low-noise uncooled immersion LEDs and photodiodes based on InAsSb solid solution are studied. The proposed optical pairs are promising for applications in compact low-voltage sensors of carbon dioxide. The threshold sensitivity of such a sensor is several hundreds of ppm, and the measurement error is no worse than 5% in a wide range of concentrations (up to 10 v/v%) at a relatively high time resolution (50 ms) and a sample volume of no greater than 50 mL. Relatively high working rate and low volume of the sample improve diagnostics in capnography and allow applications in pediatrics and side-stream capnography including measurements of instantaneous CO2 concentration in the course of breathing.


