scholarly journals Development of Innovative Materials for Forensic Examination

2021 ◽  
pp. 22-26
Author(s):  
Tatyana Ermakova ◽  
◽  
Vasily Vasiliev ◽  
Vladimir Akatyev ◽  
◽  
...  
Keyword(s):  
Physical Modeling ◽  
Soft Tissues ◽  
Experimental Studies ◽  
Gunshot Wounds ◽  
Biological Tissues ◽  
Colloidal Systems ◽  
Synthetic Compound ◽  
Forensic Examination ◽  
Synthetic Materials ◽  
Innovative Materials

In the production of experimental studies related to the modeling of the behavior of human soft tissues in such widespread types of forensic examinations as forensic ballistic, tracological, forensic examination of cold and throwing weapons, forensic medical-use bioimitators. Human corpses, animal carcasses, and their living individuals are used as such objects, but in recent decades, with the development of chemistry and chemical technology, various artificial substitutes have become increasingly widespread – colloidal systems based on gelatin, soap, mixtures of petroleum petrolatum, as well as specialized compositions. Among the main advantages of using soft tissue substitutes are the following: visibility of the results obtained, availability of synthetic materials, uniformity of structure, reproducibility of experimental results with a statistically reliable amount, as well as, if necessary, the possibility of varying mechanical parameters for physical modeling of the characteristics of human biological tissues within the framework of an expert experiment. The paper proposes a technology for obtaining a reusable synthetic compound that allows modeling the properties of human soft tissues. The synthetic compound provides the transfer of general patterns of morphology of the formed gunshot injuries, similar to gunshot wounds on biological materials.

Rapid Critical Point Drying of Tissues in a Parr Bomb

1972 ◽  
Vol 30 ◽  
pp. 400-401
Author(s):  
C.A. Baechler ◽  
W. C. Pitchford ◽  
J. M. Riddle ◽  
C.B. Boyd ◽  
H. Kanagawa ◽  
...  
Keyword(s):  
Critical Point ◽  
Critical Pressure ◽  
Soft Tissues ◽  
Biological Tissues ◽  
Critical Temperatures ◽  
Air Drying ◽  
The Past ◽  
Critical Point Drying ◽  
Great Stress ◽  
Infiltration Techniques

Preservation of the topographic ultrastructure of soft biological tissues for examination by scanning electron microscopy has been accomplished in the past by using lengthy epoxy infiltration techniques, or dehydration in ethanol or acetone followed by air drying. Since the former technique requires several days of preparation and the latter technique subjects the tissues to great stress during the phase change encountered during air-drying, an alternate rapid, economical, and reliable method of surface structure preservation was developed. Turnbill and Philpott had used a fluorocarbon for the critical point drying of soft tissues and indicated the advantages of working with fluids having both moderately low critical pressures as well as low critical temperatures. Freon-116 (duPont) which has a critical temperature of 19. 7 C and a critical pressure of 432 psi was used in this study.

scholarly journals A computational framework for modeling cell–matrix interactions in soft biological tissues

2021 ◽  
Author(s):  
Jonas F. Eichinger ◽  
Maximilian J. Grill ◽  
Iman Davoodi Kermani ◽  
Roland C. Aydin ◽  
Wolfgang A. Wall ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Three Dimensional ◽  
Biological Tissues ◽  
Computational Framework ◽  
Cell Matrix ◽  
Physiological Processes ◽  
Matrix Interactions ◽  
Mechanical Homeostasis ◽  
Cell Matrix Interactions ◽  
Short Time

AbstractLiving soft tissues appear to promote the development and maintenance of a preferred mechanical state within a defined tolerance around a so-called set point. This phenomenon is often referred to as mechanical homeostasis. In contradiction to the prominent role of mechanical homeostasis in various (patho)physiological processes, its underlying micromechanical mechanisms acting on the level of individual cells and fibers remain poorly understood, especially how these mechanisms on the microscale lead to what we macroscopically call mechanical homeostasis. Here, we present a novel computational framework based on the finite element method that is constructed bottom up, that is, it models key mechanobiological mechanisms such as actin cytoskeleton contraction and molecular clutch behavior of individual cells interacting with a reconstructed three-dimensional extracellular fiber matrix. The framework reproduces many experimental observations regarding mechanical homeostasis on short time scales (hours), in which the deposition and degradation of extracellular matrix can largely be neglected. This model can serve as a systematic tool for future in silico studies of the origin of the numerous still unexplained experimental observations about mechanical homeostasis.

A Sub-Domain Inverse Finite Element Characterization of Hyperelastic Membranes Including Soft Tissues

2003 ◽  
Vol 125 (3) ◽  
pp. 363-371 ◽  
Author(s):  
Padmanabhan Seshaiyer ◽  
Jay D. Humphrey
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Soft Tissues ◽  
Nonlinear Behavior ◽  
Local Stress ◽  
Biological Tissues ◽  
Material Behavior ◽  
Inverse Finite Element Method ◽  
Complicated Geometry ◽  
Element Method

Quantification of the mechanical behavior of hyperelastic membranes in their service configuration, particularly biological tissues, is often challenging because of the complicated geometry, material heterogeneity, and nonlinear behavior under finite strains. Parameter estimation thus requires sophisticated techniques like the inverse finite element method. These techniques can also become difficult to apply, however, if the domain and boundary conditions are complex (e.g. a non-axisymmetric aneurysm). Quantification can alternatively be achieved by applying the inverse finite element method over sub-domains rather than the entire domain. The advantage of this technique, which is consistent with standard experimental practice, is that one can assume homogeneity of the material behavior as well as of the local stress and strain fields. In this paper, we develop a sub-domain inverse finite element method for characterizing the material properties of inflated hyperelastic membranes, including soft tissues. We illustrate the performance of this method for three different classes of materials: neo-Hookean, Mooney Rivlin, and Fung-exponential.

scholarly journals Radiation diagnostics of thoracic gunshot wounds

2020 ◽  
pp. 70-80
Author(s):  
Iryna Dykan
Keyword(s):  
Soft Tissues ◽  
General Structure ◽  
Ground Glass Opacity ◽  
Gunshot Wounds ◽  
Lung Parenchyma ◽  
Combat Trauma ◽  
Side Impact ◽  
Pulmonary Contusion ◽  
Projectile Energy ◽  
Surgical Trauma

The frequency of thoracic injuries in the general structure of combat surgical trauma remains at the level of 7-12 % and unchanged from the time of the Second World War to the current armed conflicts. The overwhelming majority of them (up to 72 %) are shrapnel gunshot wounds. The formation of a gunshot wound occurs due to the action of a shock wave; a wounding projectile; energy of side impact and vortex wake. The shape, size, features of the wound canal are determined by the kinetic energy of the wounding agent and the physical properties of the damaged tissues. The lung parenchyma is loose and elastic, so small-caliber bullets with low energy cause minimal damage. The wound canal is well differentiated on CT-slices. Its cavity is filled with blood, fragments of destroyed tissue, air bubbles. On the periphery, the contusion zone is determined (area of increased attenuation in the lung-ground-glass opacity). Shrapnel wounds can be accompanied by ruptures of the pulmonary parenchyma with hemorrhages, bilateral pulmonary contusion, damage to the bone frame and soft tissues of the chest. Vascular injury with massive hemorrhage into the pleural cavity and tense hemopneumothorax are one of the main causes of mortality in penetrating wounds. Transmediastinal gunshot wounds, armor trauma and bullet embolism require special attention during radiation examination of victims. The purpose of radiation diagnostics of modern combat trauma is to identify and fully characterize injuries and their complications. The amount of diagnostic information is determined by the level of medical care. Key words: gunshot wounds, chest cavity organs, radiation diagnostics.

scholarly journals ДОСЛІДЖЕННЯ ГІГІЄНІЧНИХ ВЛАСТИВОСТЕЙ МАТЕРІАЛІВ НАТІЛЬНОЇ ЛІКАРНЯНОЇ БІЛИЗНИ

2020 ◽  
Vol 140 (6) ◽  
pp. 38-47
Author(s):  
І. О. Іванов ◽  
Н. П. Супрун ◽  
Ю. О. Ващенко
Keyword(s):  
Comparative Analysis ◽  
Materials Science ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Raw Material ◽  
Experimental Investigations ◽  
Textile Materials ◽  
Composition And Structure ◽  
Innovative Materials ◽  
Basic Functions

Investigation of the influence of the peculiarities of raw material composition and structure of traditional and innovative linen textile materials on their hygienic properties. Theoretical and experimental investigations are based on the main positions of textile materials science. In experimental studies, modern standardized methods for determining the hygienic properties of textile materials were used, as well as techniques specially developed taking into account the peculiarities of the operating conditions of underwear. The peculiarities of the operating conditions and the basic functions of hospital underwear were determined. The comparative analysis of hygienic properties of traditional and modern fabrics for underwear was carried out. Using the standardized and the developed methods, adapted to the peculiarities of the conditions of use of the products, the indicators characterizing the processes of water absorption of the materials were experimentally determined. On the basis of the obtained values of quality indicators, a comprehensive assessment of the ability of materials to transfer moisture and air, with the calculation of the arithmetic complex quality index was done. This allowed to determine the material that is optimal in properties, which provides thermophysiological comfort when operating hospital underwear. Using the developed methods, which take into account the specifics of the operating conditions, a comparative analysis of the hygienic properties of traditional and innovative materials for underwear was carried out. A new range of textile materials for underwear has been proposed, taking into account the peculiarities of the operational situation of consumption.

scholarly journals PLANNING OF EXPERIMENTAL STUDIES WITH THE PURPOSE OF DEVELOPING THE MODE OF FACING DSTP WITH A THIN SLED VENEER OF WOOD MAHAGONI

2021 ◽  
Author(s):  
Tatyana Efimova ◽  
Tatyana Ishchenko ◽  
S. Dunaev
Keyword(s):  
Wood Species ◽  
Experimental Studies ◽  
Second Order ◽  
Synthetic Materials ◽  
Natural Wood ◽  
Cost Of Production ◽  
Wood Furniture ◽  
The Cost ◽  
Huge Variety

The modern market offers mainly furniture made from traditional materials: chipboard and fiberboard, faced with synthetic materials (films, plastics). However, despite the huge variety of synthetic materials, they cannot convey the original texture, color of natural wood. Furniture made of natural wood and furniture made of panel materials, faced with sliced veneer, are classified as premium furniture due to the high cost and shortage of valuable wood species. To reduce the cost of production, it is proposed to use thin sliced and peeled veneer with a thickness of 0.4 mm. The problem is that the most common veneering defect is glue leakage, which depends on many factors, as well as the lack of clear recommendations for the choice of veneering modes. In this regard, the problem of developing a mode for veneering chipboards with thin sliced veneer of mahogany wood is relevant and requires research. The paper identifies variable factors and factors that remained constant during research. The conditions for conducting experimental studies are also given. To develop a methodology for conducting experimental studies, the method of uniform- rotatable planning of a second-order experiment was used.

scholarly journals A theoretical verification of the integral fluctuation theorem for accelerated colloidal systems in the long-time limit

2021 ◽  
Author(s):  
Yash Lokare
Keyword(s):  
Steady State ◽  
Time Scales ◽  
Numerical Study ◽  
Quantitative Description ◽  
Experimental Studies ◽  
Fluctuation Theorem ◽  
Nonequilibrium Steady States ◽  
Small Scale ◽  
Colloidal Systems ◽  
Long Time

A quantitative description of the violation of the second law of thermodynamics in relatively small classical systems and over short time scales comes from the fluctuation-dissipation theorem. It has been well established both theoretically and experimentally, the validity of the fluctuation theorem to small scale systems that are disturbed from their initial equilibrium states. Some experimental studies in the past have also explored the validity of the fluctuation theorem to nonequilibrium steady states at long time scales in the asymptotic limit. To this end, a theoretical and/or purely numerical model of the integral fluctuation theorem has been presented. An approximate general expression for the dissipation function has been derived for accelerated colloidal systems trapped/confined in power-law traps. Thereafter, a colloidal particle trapped in a harmonic potential (generated by an accelerating one-dimensional optical trap) and undergoing Brownian motion has been considered for the numerical study. A toy model of a quartic potential trap in addition to the harmonic trap has also been considered for the numerical study. The results presented herein show that the integral fluctuation theorem applies not only to equilibrium steady state distributions but also to nonequilibrium steady state distributions of colloidal systems in accelerated frames of reference over long time scales.

scholarly journals Organization of stage rehabilitation of servicemen with gunshot defects of soft tissues at the levels of medical care

2021 ◽  
Vol 26 (4) ◽  
pp. 188-195
Author(s):  
K.D. Babov ◽  
I.P. Khomenko ◽  
S.V. Tertyshnyi ◽  
Babova I.K. Babova I.K. ◽  
R.S. Vastianov
Keyword(s):  
Surgical Treatment ◽  
Soft Tissue ◽  
Medical Care ◽  
Soft Tissues ◽  
Lower Extremities ◽  
Gunshot Wounds ◽  
Care Quality ◽  
Rehabilitation Service ◽  
Soft Tissue Defects ◽  
Tissue Defects

Building a modern system of rehabilitation of servicemen in Ukraine is an integral part of providing medical care in armed conflict. Rehabilitation of servicemen after gunshot wounds with soft tissue defects of the lower extremities is a common but difficult problem for surgical and rehabilitation teams. The process of rehabilitation requires the implementation of certain methodological provisions. At present, medical care for servicemen is a four-levels’ one. Rehabilitation service is provided at the third and fourth levels of medical care. The aim of the study was to improve the quality of medical care for servicemen after gunshot wounds with soft tissue defects of the lower extremities by introducing a system of staged rehabilitation. Organizational and methodological bases of the system of staged rehabilitation of wounded servicemen with soft tissue defects at different levels of medical care have been developed. Two models of rehabilitation depending on the severity of the injury and the tactics of surgical treatment are proposed. The division of the stage of early sanatorium rehabilitation for the wounded with severe soft tissue injuries depending on the stage of surgical treatment and the formation of a "skin patch" is justified. The introduction of the proposed models of rehabilitation of wounded with soft tissue defects in the practice of early sanatorium rehabilitation will provide increasing of medical care quality.

On the analysis of the integral fluctuation theorem for accelerated colloidal systems in the long-time limit

2021 ◽  
Author(s):  
Yash Lokare
Keyword(s):  
Steady State ◽  
Time Scales ◽  
Numerical Study ◽  
Quantitative Description ◽  
Experimental Studies ◽  
Fluctuation Theorem ◽  
Nonequilibrium Steady States ◽  
Small Scale ◽  
Colloidal Systems ◽  
Long Time

Abstract A quantitative description of the violation of the second law of thermodynamics in relatively small classical systems and over short time scales comes from the fluctuation-dissipation theorem. It has been well established both theoretically and experimentally, the validity of the fluctuation theorem to small scale systems that are disturbed from their initial equilibrium states. Some experimental studies in the past have also explored the validity of the fluctuation theorem to nonequilibrium steady states at long time scales in the asymptotic limit. To this end, a theoretical and/or purely numerical model of the integral fluctuation theorem has been presented. An approximate general expression for the dissipation function has been derived for accelerated colloidal systems trapped/confined in power-law traps. Thereafter, a colloidal particle trapped in a harmonic potential (generated by an accelerating one-dimensional optical trap) and undergoing Brownian motion has been considered for the numerical study. A toy model of a quartic potential trap in addition to the harmonic trap has also been considered for the numerical study. The results presented herein show that the integral fluctuation theorem applies not only to equilibrium steady state distributions but also to nonequilibrium steady state distributions of colloidal systems in accelerated frames of reference over long time scales.

On the Ability of Structural and Phenomenological Hyperelastic Models to Predict the Mechanical Behavior of Biological Tissues Submitted to Multiaxial Loadings

2012 ◽  
Author(s):  
Mathieu Nierenberger ◽  
Yves Rémond ◽  
Saïd Ahzi
Keyword(s):  
Experimental Data ◽  
Mechanical Behavior ◽  
Strain Energy ◽  
Soft Tissues ◽  
Least Squares Method ◽  
Biological Tissues ◽  
Physical Parameters ◽  
Cauchy Stress ◽  
Specific Loading ◽  
Hyperelastic Models

Medical surgery is currently rapidly improving and requires modeling faithfully the mechanical behavior of soft tissues. Various models exist in literature; some of them created for the study of biological materials, and others coming from the field of rubber mechanics. Indeed biological tissues show a mechanical behavior close to the one of rubbers. But while building a model, one has to keep in mind that its parameters should be loading independent and that the model should be able to predict the behavior under complex loading conditions. In addition, keeping physical parameters seems interesting since it allows a bottom up approach taking into account the microstructure of the material. In this study, the authors consider different existing hyperelastic models based on strain energy functions and identify their coefficients successively on single loading stress-stretch curves. The experimental data used, come from a paper by Zemanek dated 2009 and concerning uniaxial, equibiaxial and plane tension tests on porcine arterial walls taken in identical experimental conditions. To achieve identification, the strain energy function of each model is derived differently to provide an expression of the Cauchy stress associated to each loading case. Firstly the parameters of each model are identified on the uniaxial tension curve using a least squares method. Then, keeping the obtained parameters, predictions are made for the two other loading cases (equibiaxial and plane tension) using the associated expressions of stresses. A comparison of these predictions with experimental data is done and allows evaluating the predictive capabilities of each model for the different loading cases. A similar approach is used after swapping the loading types. Since the predictive capabilities of the models are really dependent on the loading chosen to determine their parameters, another type of identification procedure is set up. It consists in adding the residues over the three loading cases during identification. This alternative identification method allows a better agreement between each model and the various types of experiments. This study evaluated the ability of some classical hyperelastic models to be used for a predictive scope after being identified on a specific loading type. Besides it brought to light some existing models which can describe at best the mechanical behavior of biological tissues submitted to various loadings.

Sign in / Sign up

Export Citation Format

Share Document