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1

Soft tissue substitute medium used in forensic and ballistic tests

Mickiewicz Wiktoria, Helnarska Karolina J., Motrycz Grzegorz

Zeszyty Naukowe SGSP / Szkoła Główna Służby Pożarniczej

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2023

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Nr 87

53--65

EN

The article presents soft tissue substitutes that are used to assess the effects of terminal ballistics of bullets. The influence of factors on the production of ballistic gelatine blocks was analyzed and described, and the results of the production of ballistic gelatine blocks were presented along with a visualization of injuries.

PL

Abstrakt W artykule dokonano prezentacji substytutów tkanki miękkiej, które wykorzystywane są do oceny skutków balistyki końcowej pocisków. Dokonano analizy i opisu wpływu czynników na wykonanie bloków żelatyny balistycznej oraz zaprezentowano wyniki z wykonania bloków żelatyny balistycznej wraz z wizualizacją obrażeń.

2

Estimation of hydromechanical parameters of limb lymphedematous tissue with the use of chamber tests

Kaczmarek Mariusz, Nowak Joanna, Olszewski Waldemar, Zaleska Marzanna

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 1

149--161

EN

Purpose: In this paper, in vivo methods of estimation of the shear modulus and hydraulic permeability of subcutaneous tissue of lower limb are presented. Methods: The experimental technique is based on single- or two-chamber inflation-deflation tests in which temporal changes in limb circumference under the test chamber for cyclic loading are registered. Simplified models for fast undrained deformation and slow creep of oedematous tissue with squeezing out interstitial liquid were considered. Finite element simulations of the chamber test within a finite deformation poroelastic model were elaborated. Results: Formulas necessary to estimate the shear modulus and permeability of subcutaneous tissue were derived and then tested or calibrated using the results of poroelastic simulations. An example of application of the derived formulas for clinical data obtained from the chamber test was discussed. Conclusions: A simple in vivo methods of estimation of the hydromechanical properties of lymphedematous tissue (shear modulus and permeability) were proposed. The strengths and weaknesses of the proposed methodology were discussed.

3

Model of multipath propagation of ultrasonic pulses in soft tissue using divergent beam tomography method

Borowski Jędrzej, Opieliński Krzysztof J.

Vibrations in Physical Systems

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2019

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Vol. 30, nr 1

art. no. 2019130

EN

The paper presents the model of calculating ultrasound waveform beam emitted inside the circular space of ultrasonic transducer ring array and propagated through a biological medium submerged in water. Each elementary transducer emits a burst signal, which then propagates through a medium and is received by a number of transducers on the opposite side of the ring array. The method allows for calculating runtime and amplitude of ultrasonic bursts while traveling from an emitter to a receiver through a specified soft tissue section geometry, having regard to the refraction and attenuation effects and directivity pattern of transducers. The soft tissue section geometry is constructed using circular shapes with given ultrasound speed and attenuation distribution. The elaborated software creates a set of received waveforms for each transmitting transducer. The presented results produced by the software can be used as a basis for further research on inverse problems in ultrasound waveform tomography.

4

Comparison of the image compounding methods for the multi-angle 3-D ultrasound imaging

Sabiniok Maciej, Opieliński Krzysztof

Vibrations in Physical Systems

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2019

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Vol. 30, nr 1

art. no. 2019134

EN

The main goal of the paper is to compare the image compounding methods to minimise the artefacts arising in the Multi-Angle Conventional Ultrasound Imaging (MACUI) due to the system configuration. The MACUI method used for 3-D object imaging and the introduced imaging artefacts are described. Different ways of the image compounding by intensity averaging are presented in the work. Implemented methods of image compounding were tested for different types of objects mimicking soft tissue. The comparison allowed to determine the most appropriate method of intensity averaging in the compounding method. The method can be used to reduce the presence of image artefacts and enhance the quality of the resulting slices which are used to create 3-D volume of an object structure in MACUI method.

5

Experimental testing and constitutive modeling of the mechanical properties of the swine skin tissue

Łagan S. D., Liber-Kneć A.

Acta of Bioengineering and Biomechanics

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2017

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Vol. 19, no. 2

93--102

EN

The aim of the study was an estimation of the possibility of using hyperelastic material models to fit experimental data obtained in the tensile test for the swine skin tissue. Methods: The uniaxial tensile tests of samples taken from the abdomen and back of a pig was carried out. The mechanical properties of the skin such as the mean Young’s modulus, the mean maximum stress and the mean maximum elongation were calculated. The experimental data have been used to identify the parameters in specific strain-energy functions given in seven constitutive models of hyperelastic materials: neo-Hookean, Mooney–Rivlin, Ogden, Yeoh, Martins, Humphrey and Veronda–Westmann. An analysis of errors in fitting of theoretical and experimental data was done. Results: Comparison of load –displacement curves for the back and abdomen regions of skin taken showed a different scope of both the mean maximum loading forces and the mean maximum elongation. Samples which have been prepared from the abdominal area had lower values of the mean maximum load compared to samples from the spine area. The reverse trend was observed during the analysis of the values of elongation. An analysis of the accuracy of model fitting to the experimental data showed that, the least accurate were the model of neo- -Hookean, model of Mooney–Rivlin for the abdominal region and model of Veronda–Westmann for the spine region. Conclusions: An analysis of seven hyperelastic material models showed good correlations between the experimental and the theoretical data for five models.

6

Skinfold creep under load of caliper. Linear visco- and poroelastic model simulations

Nowak J., Nowak B., Kaczmarek M.

Acta of Bioengineering and Biomechanics

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2015

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Vol. 17, no. 4

39--48

EN

Purpose: This paper addresses the diagnostic idea proposed in [11] to measure the parameter called rate of creep of axillary fold of tissue using modified Harpenden skinfold caliper in order to distinguish normal and edematous tissue. Our simulations are intended to help understanding the creep phenomenon and creep rate parameter as a sensitive indicator of edema existence. The parametric analysis shows the tissue behavior under the external load as well as its sensitivity to changes of crucial hydro-mechanical tissue parameters, e.g., permeability or stiffness. Methods: The linear viscoelastic and poroelastic models of normal (single phase) and oedematous tissue (twophase: swelled tissue with excess of interstitial fluid) implemented in COMSOL Multiphysics environment are used. Simulations are performed within the range of small strains for a simplified fold geometry, material characterization and boundary conditions. The predicted creep is the result of viscosity (viscoelastic model) or pore fluid displacement (poroelastic model) in tissue. Results: The tissue deformations, interstitial fluid pressure as well as interstitial fluid velocity are discussed in parametric analysis with respect to elasticity modulus, relaxation time or permeability of tissue. The creep rate determined within the models of tissue is compared and referred to the diagnostic idea in [11]. Conclusions: The results obtained from the two linear models of subcutaneous tissue indicate that the form of creep curve and the creep rate are sensitive to material parameters which characterize the tissue. However, the adopted modelling assumptions point to a limited applicability of the creep rate as the discriminant of oedema.

7

Komputerowy model mechanicznego zespolenia ścian żołądka

Karczewska M.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2015

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Vol. 21, nr 4

191--200

PL

Celem pracy jest zoptymalizowanie połączenia szytego ścian żołądka. Optymalizacja ma obejmować zmianę konfiguracji zszywek, co wpłynie na poprawę szczelności zespolenia. W niniejszej pracy omówiony został sposób tworzenia modelu elementów skończonych MES tkanki miękkiej. Przedstawione założenia będą stanowić bazę do dalszych modyfikacji, opartych na danych materiałowych, zebranych w trakcie badań elastyczności próbek tkanki żołądka. Działania te mają na celu znalezienie modelu hipersprężystego, najlepiej opisującego charakter badanego materiału.

EN

The main goal of this work is optimization of the surgical connection (sutures) of stomach walls. The staples’ configuration changes should be reflected in the improved anastomotic tightness. In this paper it is explained how to create the FEM model of soft tissue. It will be a base for further modifications based on the material data collected during the study of flexibility of stomach tissue samples. The main goal is determine the hyperelastic model optimally describing the nature of the tested material.

8

Non-integer viscoelastic constitutive law to model soft biological tissues to in-vivo indentation

Demirci N., Tönük E.

Acta of Bioengineering and Biomechanics

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2014

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Vol. 16, no. 4

13--21

EN

Purpose: During the last decades, derivatives and integrals of non-integer orders are being more commonly used for the description of constitutive behavior of various viscoelastic materials including soft biological tissues. Compared to integer order constitutive relations, non-integer order viscoelastic material models of soft biological tissues are capable of capturing a wider range of viscoelastic behavior obtained from experiments. Although integer order models may yield comparably accurate results, non-integer order material models have less number of parameters to be identified in addition to description of an intermediate material that can monotonically and continuously be adjusted in between an ideal elastic solid and an ideal viscous fluid.Methods: In this work, starting with some preliminaries on non-integer (fractional) calculus, the “spring-pot”, (intermediate mechanical element between a solid and a fluid), non-integer order three element (Zener) solid model, finally a user-defined large strain non-integer order viscoelastic constitutive model was constructed to be used in finite element simulations. Using the constitutive equation developed, by utilizing inverse finite element method and in vivo indentation experiments, soft tissue material identification was performed. Results: The results indicate that material coefficients obtained from relaxation experiments, when optimized with creep experimental data could simulate relaxation, creep and cyclic loading and unloading experiments accurately.Conclusions: Non-integer calculus viscoelastic constitutive models, having physical interpretation and modeling experimental data accurately is a good alternative to classical phenomenological viscoelastic constitutive equations.

9

A new medical device to measure a stiffness of soft materials

Oflaz H., Baran O.

Acta of Bioengineering and Biomechanics

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2014

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Vol. 16, no. 1

125--131

EN

An objective in vivo measurement technique for assessing the material properties of soft tissue would be a valuabe tool in diagnosing dermatological pathologies. In order to make advancements in this field, a new hand-held device was designed to measure the stiffness of soft materials. The device measures the reaction forces experienced by the soft tissue under constant indentation deformations at the time of stiffness measurement. Agarose gel samples were prepared in a range of molarities to mimic the stiffness variabilities found in vivo. The stiffness of each gel was evaluated using two different measurement techniques. The first method utilized an industry standard durometer, designed to measure the hardness of materials in shore type 00 scales of soft plastics. The second measurement was taken using an original custom-built soft tissue stiffness meter, designed specifically for the present study. These two devices were compared and a strong correlation was found between them (r2 = 1.00, Spearman rank test). Additionally, it was observed that gels of different stiffness could be distinguished by both devices. In conclusion, the soft tissue stiffness can be accurately evaluated using the proposed device. The new device should be evaluated on human subjects in future studies, before it can be used to assess soft tissue disorders.

10

The simulation of mastication efficiency of the mucous-borne complete dentures

Żmudzki J., Chladek G., Malara P., Dobrzański L.A., Zorychta M., Basa K.

Archives of Materials Science and Engineering

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2013

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Vol. 63, nr 2

75--86

EN

Purpose: The aim of this study was to present rules for numerical investigations of mastication efficiency of mucous-borne complete dentures. Design/methodology/approach: Finite element method (FEM) large displacements analysis with denture detaching and sliding at mucous membrane interface was employed. The possibility of a lower denture destabilization under oblique mastication load was modeled. Denture stabilization at balancing contact „at time” and „delayed” was modeled with increasing of a distance to the opposite denture. An unfavorable mucous membrane foundation was assumed. Findings: Pressures beneath dentures during stable vertical occlusal loadings are lower than pain threshold of mucous membrane even when the denture foundation was very unfavorable. Simulation of realistic oblique mastication force results in a denture destabilization. Denture experienced a large slide, completely lost adherence at balancing side and the balancing contact was needed to achieve stabilization. The pressures beneath denture under oblique load increased to values much higher than pain threshold and the „delayed” balancing contact influenced additional increase of pressure values. Research limitations/implications: In the FEM study only characteristic unfavorable denture foundation and conventional denture type were analyzed. Practical implications: Defined values of pressure beneath dentures show that it is necessary to underlay the dentures. The influence of „delayed” balancing contact on significant increase of stress beneath dentures indicates that in case of a problem with stabilization of dentures it is necessary to introduce stabilization on the implants. Originality/value: Universal rules of conducting a numerical experiment and interpreting its results constitute the base and encouragement to complete further practical tasks awaiting engineers and prosthetists.

11

Wpływ zmienności właściwości fizycznych tkanki na rozkład temperatury w tkance przy terapeutycznym oddziaływaniu ultradźwięków

Kruglenko E.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2012

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Vol. 18, nr 4

250--254

PL

Artykuł dotyczy numerycznego wyznaczania in vivo przestrzennego i czasowego rozkładu temperatury po oddziaływaniu na tkankę zogniskowaną wiązką ultradźwiękową małej mocy. Celem pracy jest analiza wpływu parametrów fizycznych tkanki na rozkład temperatury oraz przedstawienie wyników obliczeń dla modelu wątroby szczura, w którym uwzględniono zależność parametrów fizycznych tkanki od temperatury. Wykazano, że przewidywana temperatura tkanki po 20-minutowym oddziaływaniu w większym stopniu zależy od zmiany przewodnictwa cieplnego tkanki niż od jej ciepła właściwego. Parametry materiałowe wody i tkanki wątroby przyjęto na podstawie danych z literatury. Założono, że geometria modelu numerycznego odpowiada rzeczywistemu położeniu obszaru oddziaływania względem głowicy emitującej zogniskowaną wiązkę ultradźwiękową.

EN

The paper concerns the numerical calculation of the spatiotemporal distribution of the temperature field induced by a low power focused ultrasound beam within tissues in vivo. The aim of the study was to analyze the influence of various tissue parameters on the temperature distribution and to present the results of calculations for the rat liver model, taking into account the dependence of physical parameters on the temperature. It was shown that the predicted tissue temperature after 20 minutes of interaction depends more on the tissue thermal conductivity than its heat capacity. The material parameters of water and liver tissue were taken from the literature, and the geometry of numerical model corresponds to the actual location of the interaction area of the transducer emitting highly focused ultrasound beam.

12

Badania modelowe rozkładu naprężeń kontaktowych na powierzchni błony śluzowej pod protezami zębowymi metodą elementów skończonych

Żmudzki J.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2011

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Vol. 17, nr 3

235-238

PL

Użytkownicy konwencjonalnych protez zębowych osiadających często cierpią z powodu urazów tkanek miękkich i bólu. Mechanizmy oddziaływania pomiędzy twardymi siodłami protez a powierzchnią błony śluzowej, które decydują o biomechanice protezy, są słabo poznane, szczególnie w warunkach obciążeń zgryzowych odpowiadających realnym funkcjom żucia. W pracy przedstawiono numeryczne trójwymiarowe badania symulacyjne MES (Metoda Elementów Skończonych), w których uwzględniono możliwość odrywania protezy oraz przesuwu z tarciem na powierzchni błony śluzowej. W obliczeniach kontaktu zastosowano rozszerzone sformułowanie mnożników Lagrange'a z implementacją klasycznego liniowego modelu tarcia. Przyjęto warunki obciążenia protezy z uwzględnieniem działania skośnych sił zgryzowych oraz założono możliwość zaistnienia kontaktu zwarciowego z protezą górną po stronie balansującej. Zastosowana metodyka badań modelowych pozwoliła na rozpoznanie zjawisk towarzyszących przeciwdziałaniu destabilizacji dolnej protezy poprzez kontakty zwarciowe po stronie balansującej.

EN

The users of conventional dental prostheses, commonly suffer from pain and injuries. The interaction mechanisms between hard denture saddles and mucous membrane surface, which decide on denture biomechanics, are not deeply understood, especially under the conditions of occlusal loads reflecting real mastication functions. In this paper, 3D numerical FEM (Finite Element Method) simulation, in which the possibility of detaching denture and slipping with friction on the surface of mucous membrane, is presented. In calculations, the multiplier Lagrangian formulation with implemented classical linear friction model, was exploited. It was assumed that the denture loading i s the oblique occlusal force. The possible occurrence of occlusal contact with upper denture at the balancing side, was considered, as well. The presented model analysis enabled to determine phenomena counteracting destabilization of the lower denture, by means of occlusal contacts at the balancing side.

13

Spawanie żywych tkanek miękkich.

Ivanowa O.N.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2005

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R. 49, nr 1

59-62

PL

Omówiono zagadnienia dotyczące spawania żywych tkanek z zastosowaniem prądów o dużej częstotliwości. Metoda ta jest wykorzystywana do rozdzielania tkanek, jak również w celu zatrzymania lub zapobiegania krwawieniu w wyniku rozcinania tkanek i naczyń. Określono warunki tworzenia się połączeń spawanych tkanek miękkich z zastosowaniem prądów o dużej częstotliwości oraz opracowano stanowisko spawalnicze. Omówiono mechanizm tworzenia się połączeń żywych tkanek oraz określono obszar stosowania opracowanej metody elektrochirurgii. Przytoczono przykłady zastosowań technologii spawalniczej w praktyce lekarskiej.

EN

The questions regarding to high-frequency welding of live tissues are discussed. The method is applied in order to separate the tissues as well as stanch blood or prevent bleeding in consequence of cutting tissues and vessels. It has been determined the conditions of formation of live tissue joints and the suitable welding station has been designed. The mechanism of formation of live tissue joints has been presented and the scope of application of this new-developed electrosurgical method has been defined. The examples of application of welding technology to medical practice are given.

14

2D rheological models for stress relaxation and creep in living soft tissues

Kobelev A. V., Kobeleva R. M., Protsenko Y. L.

Acta of Bioengineering and Biomechanics

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2005

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Vol. 7, nr 1

23-34

EN

Identified rheological 2D models of myocardium proposed earlier by us to analyze static 'forcedeformation" curves and ąuasi-static hysteresis loops are used to describe stress relaxation and creep in a wide range of living soft tissues, beginning with myocite level and up to the muscle fibers. The viscous properties are determined with the help of the dampers connected in series or in parallel to certain elastic primary elements of the models. The stress response functions of the models are found for the external longitudinal step-wise or pulse (colurnn-like) stretching. The inverse response functions of the longitudinal displacement for the external stress loading of the pulse shape time dependencies are also found. The values of both elastic modules, as in the static case. and also viscous coefficients are esrimated by comparing theoretical curves of relaxation, creep and recovery with the experirnental data. The latter are obtained on rather different objects, passive muscles preparations (the stress relaxation response) and endothelium cells (the creep response). It IS stated that 2D models proposed appear to be too generał to describe nonlinear relaxation and creep properties. which are lacking the traditionally used ID ones without essential modification of those models.

15

Model matematyczny ruchu kończyn dolnych człowieka uwzględniający ruch tkanek miękkich

Michnik R., Tejszerska D.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2001

|

z. 17

125-130

PL

W niniejszej pracy opracowano model matematyczny ruchu kończyn dolnych człowieka, w którym w uproszczony sposób uwzględniono ruch tkanek miękkich. Oddziaływanie tkanek miękkich na układ szkieletowy zamodelowano poprzez wprowadzenie tzw. mas drgających.

EN

Mathematical model of motion of human lower limbs, considering motion of soft tissues, in simplified manner, was elaborated in presented work. The interaction between soft tissues and bones was modeled by introduction of wobbling masses, simulating soft tissues.