scholarly journals Application of Sampling Methods to Nanostructures on the Example of Cellular Structures of Cardiac Arrhythmia Dynamics

2020 ◽  
Vol 4 (1) ◽  
Keyword(s):  
Cardiac Arrhythmia ◽  
Dynamic Systems ◽  
Sampling Methods ◽  
Cardiac Activity ◽  
Heart Tissue ◽  
Cellular Structures ◽  
Universal Model ◽  
Conductive System

This publication discusses models that describe the heart tissue as an active conductive system, taking into account its self-oscillating properties. In this type of models, cardiac rhythms can be described on the basis of the theory of dynamic systems, which justifies the need to build a universal model of oscillating medium. This type of model contributes to the understanding of these pathologies cardiac activity as parasecoli and AB-blockade.

scholarly journals Polynomial Model of Two Interacting Pacemakers Taking into Account the Time of Refractoriness

2019 ◽  
pp. 1-6
Author(s):  
Sergey Belyakin ◽  
◽  
Sergey Shuteev ◽  
Keyword(s):  
Dynamic Systems ◽  
Cardiac Activity ◽  
Heart Tissue ◽  
Polynomial Model ◽  
Universal Model ◽  
Conductive System

This publication discusses models that describe the heart tissue as an active conductive system, taking into account its self-oscillating properties. In this type of models, cardiac rhythms can be described on the basis of the theory of dynamic systems, which justifies the need to build a universal model of oscillating medium. This type of model contributes to the understanding of these pathologies cardiac activity as parasecoli and AB-blockade

scholarly journals Graph-analytical interpretation and modeling of phase portraits of cellular structures during their phase transformations

2018 ◽  
Vol 170 ◽  
pp. 01135
Author(s):  
Vladimir Kulikov
Keyword(s):  
Dynamical Systems ◽  
Dynamic Systems ◽  
Recursive Algorithm ◽  
Laser Speckle ◽  
Phase Portraits ◽  
Cellular Structures ◽  
Simulation Algorithm ◽  
Systems Models ◽  
Initial States ◽  
Discrete Moments

The article shows the possibility of representing the state of the cellular structures in the form of “phase portraits” of states in discrete moments of time. The generated structures are presented in the form of dynamic systems. Models of states of dynamical systems, is developed, based on the analysis and processing of laser speckle and other structures. The simulation algorithm of the phase portraits given in the paper allows to create information systems casts at given discrete points in time, and to control the process of formation of properties of structures. The transition of the studied systems from their initial states to the final presents a recursive algorithm with deferred calculation of the parameters of designed objects. The initial parameters of the studied systems are reported in the form of a graphic-analytical statistics and are defined further as texture geometric shapes of cellular structures.

scholarly journals Correlation of the distribution of antioxidant enzyme concentrations in blood serum and heart tissue in rats

2020 ◽  
Vol 17 ◽  
pp. 00234
Author(s):  
Pavel Boriskin ◽  
Olga Gulenko ◽  
Anatoly Devyatkin ◽  
Rufia Karimova ◽  
Victor Leonov ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Lipid Peroxidation ◽  
Blood Serum ◽  
Free Radical Oxidation ◽  
Correlation Coefficients ◽  
Heart Tissue ◽  
Cellular Structures ◽  
Weak Correlation ◽  
Radical Oxidation ◽  
Disease Markers

Cardiovascular diseases have been the leading cause of death worldwide for many years. In recent years, new cardiovascular disease markers have been sought that can improve the diagnosis and treatment of this broad and prognostically unfavorable group of diseases. The efforts of many researchers are aimed at detecting changes in the level of enzymes in the lipid peroxidation system, which are antioxidants, as possible mechanisms underlying the development of cardiovascular disease. The imbalance between the intensification of free-radical oxidation caused by active oxygen forms and the activity of the body’s protective antioxidant system leads to serious disturbances: disorganization of cellular structures, changes in their functional activity. The article presents the study of the interrelation of the concentration distribution of enzymes of the lipid peroxidation system – antioxidants in blood serum and heart tissues of white non-pedigree rats. The correlation coefficients of Spearman, the gamma of correlation and Kendel Tau revealed a reliable presence of weak correlation between the concentration of glutathione peroxidase in blood serum and heart tissues (Spearman R = 0.18 at p ≤ 0.029408, Gamma = 0.14 at p ≤ 0.018701; Kendall Tau = 0.13 at p ≤ 0.018701).

Uranyl Acetate as a Stain and a Fixative for Heart Tissue

1969 ◽  
Vol 27 ◽  
pp. 412-413
Author(s):  
M. A. Hayat
Keyword(s):  
Nucleic Acids ◽  
Osmium Tetroxide ◽  
Heart Tissue ◽  
Uranyl Acetate ◽  
Cellular Structures ◽  
Mitochondrial Matrix ◽  
Double Staining ◽  
Lead Salts ◽  
Wide Range ◽  
Cell Components

Lead salts show affinity for a wide range of cellular structures and they increase general contrast much more intensely than any other known electron stain. However, lead stains do not show a strong affinity for nucleic acids, especially DNA. Since uranyl salts exhibit special affinity for nucleic acids, double staining of sections with uranyl acetate followed by lead acetate has become quite popular. Uranyl acetate is also an excellent fixative provided the tissue is treated with this reagent prior to dehydration. After double fixation with glutaraldehyde and osmium tetroxide, uranyl acetate treatment prior to dehydration markedly improves the preservation of all cell components especially that of nucleic acids, ground proteins, myofibril including Z bands, and mitochondrial matrix. Thus, when employed prior to dehydration, uranyl acetate acts not only as a stain but also as a general fixative for both nucleic acids and proteins (Hayat, 1969). Uranyl acetate is so easy to apply to both the tissue block and the sections that there seems no reason for not routinely using it for general staining. In the present study, tissues were exposed to uranyl acetate twice. The details of the method used are given below.

Influence of Adsorbent Nature on the Dynamic Headspace Study of Insect Semiochemicals

2017 ◽  
Vol 70 (8) ◽  
pp. 902 ◽  
Author(s):  
Sergio A. Rodriguez ◽  
María L. Paliza ◽  
Monica A. Nazareno
Keyword(s):  
Dynamic Systems ◽  
Eucalyptus Globulus ◽  
Lower Cost ◽  
Sampling Methods ◽  
Dynamic Headspace ◽  
Adsorption Selectivity ◽  
Porapak Q ◽  
Volatile Organic ◽  
Insect Semiochemicals ◽  
Reported Data

In chemical ecology studies (insect–insect, insect–plant relationships), it is important to choose the appropriate sampling methods and the correct optimization of sampling by using dynamic systems. In the present work, different adsorbents were evaluated in a dynamic system that presents a stream of purified air flowing through an aeration chamber containing a mixture of volatile organic compounds, mainly insect semiochemicals such as α-pinene, sulcatone, β-linalool, menthone, isomenthone, methyl salicylate, grandlure I, grandlure II, grandlure III, grandlure IV, eugenol, and α-ionone. Traditional adsorbents such as Tenax TA, Porapak Q, Hayesep Q, and activated charcoal were evaluated; further, alternatives such as Porapak Rxn RP, HLB, SCX, and silica gel, among others were proposed owing to their lower cost. The results demonstrated that Porapak Q and Porapak Rxn RP, despite their different chemical composition, were able to produce similar ratios of compounds to that of the reference solution and, moreover, with the highest recovery yields. However, it is important to emphasize the adsorption selectivity provided by SCX for eugenol and α-ionone. When Porapak Rxn RP was used in the analysis of Eucalyptus globulus volatiles, excellent results were obtained, and these agree with reported data from a hydrodistillation method.

Preparatory Procedures for Electron Microscopic Analysis at the Molecular Level of Resolution

1978 ◽  
Vol 36 (3) ◽  
pp. 516-520
Author(s):  
F.J. Sjostrand
Keyword(s):  
Electron Microscope ◽  
Molecular Level ◽  
Microscopic Analysis ◽  
Resolving Power ◽  
Cellular Structures ◽  
Electron Microscopic ◽  
Systematic Analysis ◽  
Technical Developments ◽  
Thin Sectioning ◽  
Obvious Reason

In the 1940's and 1950's electron microscopy conferences were attended with everybody interested in learning about the latest technical developments for one very obvious reason. There was the electron microscope with its outstanding performance but nobody could make very much use of it because we were lacking proper techniques to prepare biological specimens. The development of the thin sectioning technique with its perfectioning in 1952 changed the situation and systematic analysis of the structure of cells could now be pursued. Since then electron microscopists have in general become satisfied with the level of resolution at which cellular structures can be analyzed when applying this technique. There has been little interest in trying to push the limit of resolution closer to that determined by the resolving power of the electron microscope.

Some aspects of the defect structure in an austenitic stainless steel

1978 ◽  
Vol 36 (1) ◽  
pp. 314-315
Author(s):  
R. Gonzalez ◽  
L. Bru
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cellular Structures ◽  
Total Strain Amplitude ◽  
Total Deformation ◽  
Density Of Dislocations ◽  
Planar Arrays ◽  
Stacking Fault Tetrahedra ◽  
Distribution Of Dislocations ◽  
Very High

The analysis of stacking fault tetrahedra (SFT) in fatigued metals (1,2) is somewhat complicated, due partly to their relatively low density, but principally to the presence of a very high density of dislocations which hides them. In order to overcome this second difficulty, we have used in this work an austenitic stainless steel that deforms in a planar mode and, as expected, examination of the substructure revealed planar arrays of dislocation dipoles rather than the cellular structures which appear both in single and polycrystals of cyclically deformed copper and silver. This more uniform distribution of dislocations allows a better identification of the SFT.The samples were fatigue deformed at the constant total strain amplitude Δε = 0.025 for 5 cycles at three temperatures: 85, 293 and 773 K. One of the samples was tensile strained with a total deformation of 3.5%.

Phase behavior of cationic and anionic surfactants at low concentrations

1992 ◽  
Vol 50 (1) ◽  
pp. 694-695
Author(s):  
E. Naranjo
Keyword(s):  
Phase Behavior ◽  
Structural Characterization ◽  
Dynamic Systems ◽  
Anionic Surfactants ◽  
Intermolecular Forces ◽  
Stable Form ◽  
Surfactant Mixtures ◽  
Low Concentrations ◽  
Cationic And Anionic Surfactants ◽  
General Method

Equilibrium vesicles, those which are the stable form of aggregation and form spontaneously on mixing surfactant with water, have never been demonstrated in single component bilayers and only rarely in lipid or surfactant mixtures. Designing a simple and general method for producing spontaneous and stable vesicles depends on a better understanding of the thermodynamics of aggregation, the interplay of intermolecular forces in surfactants, and an efficient way of doing structural characterization in dynamic systems.

Going Beyond 3-D Imaging: Automated 3-D Montaged image Analysis of Cytological Specimens

1996 ◽  
Vol 54 ◽  
pp. 282-283
Author(s):  
Badrinath Roysam ◽  
Hakan Ancin ◽  
Douglas E. Becker ◽  
Robert W. Mackin ◽  
Matthew M. Chestnut ◽  
...  
Keyword(s):  
Image Analysis ◽  
Structural Changes ◽  
Sampling Methods ◽  
Spatial Clustering ◽  
Three Dimensional ◽  
Field Of View ◽  
Cell Counting ◽  
Depth Of Field ◽  
Tissue Cell ◽  
Tissue Organization

This paper summarizes recent advances made by this group in the automated three-dimensional (3-D) image analysis of cytological specimens that are much thicker than the depth of field, and much wider than the field of view of the microscope. The imaging of thick samples is motivated by the need to sample large volumes of tissue rapidly, make more accurate measurements than possible with 2-D sampling, and also to perform analysis in a manner that preserves the relative locations and 3-D structures of the cells. The motivation to study specimens much wider than the field of view arises when measurements and insights at the tissue, rather than the cell level are needed.The term “analysis” indicates a activities ranging from cell counting, neuron tracing, cell morphometry, measurement of tracers, through characterization of large populations of cells with regard to higher-level tissue organization by detecting patterns such as 3-D spatial clustering, the presence of subpopulations, and their relationships to each other. Of even more interest are changes in these parameters as a function of development, and as a reaction to external stimuli. There is a widespread need to measure structural changes in tissue caused by toxins, physiologic states, biochemicals, aging, development, and electrochemical or physical stimuli. These agents could affect the number of cells per unit volume of tissue, cell volume and shape, and cause structural changes in individual cells, inter-connections, or subtle changes in higher-level tissue architecture. It is important to process large intact volumes of tissue to achieve adequate sampling and sensitivity to subtle changes. It is desirable to perform such studies rapidly, with utmost automation, and at minimal cost. Automated 3-D image analysis methods offer unique advantages and opportunities, without making simplifying assumptions of tissue uniformity, unlike random sampling methods such as stereology.12 Although stereological methods are known to be statistically unbiased, they may not be statistically efficient. Another disadvantage of sampling methods is the lack of full visual confirmation - an attractive feature of image analysis based methods.

Improving Feeding Outcomes in the NICU: Moving From Volume-Driven to Infant-Driven Feeding

2010 ◽  
Vol 19 (3) ◽  
pp. 68-74 ◽  
Author(s):  
Catherine S. Shaker
Keyword(s):  
Intensive Care Unit ◽  
Dynamic Systems ◽  
Neonatal Intensive Care ◽  
Well Being ◽  
Dynamic Systems Theory ◽  
Feeding Problems ◽  
Care Giving ◽  
Extremely Preterm ◽  
Extremely Preterm Infants

Current research on feeding outcomes after discharge from the neonatal intensive care unit (NICU) suggests a need to critically look at the early underpinnings of persistent feeding problems in extremely preterm infants. Concepts of dynamic systems theory and sensitive care-giving are used to describe the specialized needs of this fragile population related to the emergence of safe and successful feeding and swallowing. Focusing on the infant as a co-regulatory partner and embracing a framework of an infant-driven, versus volume-driven, feeding approach are highlighted as best supporting the preterm infant's developmental strivings and long-term well-being.

Sign in / Sign up

Export Citation Format

Share Document