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1
Content available Modeling of photochemical and photothermal effects in soft tissue subjected to laser irradiation
Jasiński Marek, Zadoń Maria
Computer Assisted Methods in Engineering and Science
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2024
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Vol. 31, no. 1
29--50
EN
The purpose of this study is to analyze the phenomena that occur in biological tissueduring photodynamic therapy (PDT). Under the influence of the laser, triplet oxygen istransformed into singlet oxygen, which is cytotoxic to cancer tissue. The impact of thelaser on the tissue may also be accompanied by changes in the thermophysical parameters,e.g., perfusion, which can affect the supply of oxygen to the tissue and, consequently,the outcome of the therapy. The proposed model uses the optical diffusion equation,the Pennes bioheat transfer equation, and reactions equations for PDT. The connectionbetween bioheat transfer and PDT models is taken into account through the respectiverelationships between perfusion rate, capillary blood velocity, and the maximum oxygensupply rate. Furthermore, a method is proposed to model abnormal vascular patterns inthe tumor subdomain. The boundary element method and the finite difference methodwere used in the numerical implementation stage.
2
Content available Selected aspects of the operation of dual active bridge DC/DC converters
Bachman Serafin, Turzyński Marek, Jasiński Marek
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2024
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Vol. 72, nr 5
art. no. e150807
EN
This review paper discusses the concept of a bidirectional dual active bridge (DAB) DC/DC converter. Practical applications and control methods are explored, and various types of DAB converters are introduced and characterized. Aspects of operation are discussed, and enriched by the results of theoretical analyses, simulations, and experimental measurements of the original authors’ work.
3
Content available Modeling of the influence of elevated temperature on oxygen distribution in soft tissue
Jasiński Marek, Zadoń Maria
Engineering Transactions
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2023
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Vol. 71, iss. 3
287--306
EN
The purpose of the study was to analyze the combined model of bioheat transfer and oxygen distribution in tissue during exposition to the external heat impulse. The effect of temperature and thermal damage to the tissue on the values of its thermophysical parameters was taken into account. The variable value of the perfusion coefficient affects the blood velocity in the capillary and thus the distribution of the partial oxygen pressure in the tissue. Various models of the oxygen dissociation curves were also considered and a sensitivity analysis was performed for the parameters of the oxygen distribution model. In the numerical realization stage, the finite difference method and the shooting method were used.
4
Content available Numerical analysis of the thermal damage process of the tissue-blood vessel system and distribution of oxygen in the tissue
Jasiński Marek
Journal of Theoretical and Applied Mechanics
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2022
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Vol. 60 nr 2
199--212
EN
The paper presents a numerical analysis of the thermal damage process taking place in biological tissue containing a blood vessel during laser irradiation. The internal heat source resulting from laser irradiation based on the solution of the optical diffusion equation is taken into account. The investigation was concerned with the influence of tissue denaturation and oxygen content in blood on temperature distribution. The analysis of oxygen transport to the tissue is treated as a part of the analysis of thermal damage processes. At the stage of numerical computations, the boundary element method and the finite difference method were used.
5
Content available Numerical analysis of thermal damage and oxygen distribution in laser irradiated tissue
Jasiński Marek
Journal of Applied Mathematics and Computational Mechanics
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2022
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Vol. 21, nr 2
51--62
EN
A numerical analysis of the thermal damage process that proceeds in biological tissue during laser irradiation is presented. Heat transfer in the tissue is assumed to be transient and two-dimensional. The internal heat source resulting from the laser irradiation based on the solution of optical diffusion equation is taken into account. Changes in tissue oxygen distribution resulting from temperature changes are analyzed using the Krogh cylinder model with Michaelis-Menten kinetics. A Hill model was used to describe the oxyhemoglobin dissociation curve. At the stage of numerical realization, the boundary element method and the finite difference method have been applied.
6
Content available Mathematical modeling of the phenomena that occur in a biological tissue containing photosensitizer
Jasiński Marek, Zadoń Maria
Journal of Applied Mathematics and Computational Mechanics
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2022
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Vol. 21, nr 4
40--51
EN
The aim of the study is to analyze photothermal and photochemical phenomena that occur during photodynamic therapy (PDT). In this type of therapy, under the influence of the laser, reactions take place related to the transformation of triplet oxygen form into its singlet form which is cytotoxic to the tissue. The increases in temperature resulting from the laser-tissue interaction during PDT are not big; however, they can lead to changes in tissue perfusion, which can affect oxygen delivery to the tissue. The proposed model uses optical diffusion equation, Pennes bioheat transfer equation, and reactions equations for PDT. The main findings of the analysis show the impact of temperature on the value of the perfusion coefficient and triplet oxygen distributions at the end of the treatment procedure.
7
Content available Eksperymentalne porównanie modułów ładowania pojazdów elektrycznych wykonanych w technologii krzemowej i węglika krzemu
Piasecki Szymon, Załęski Jarosław, Jasiński Marek
Maszyny Elektryczne : zeszyty problemowe
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2021
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Nr 2 (126)
47--52
PL
Artykuł przedstawia porównanie sprawności modułów ładowarek o mocy 50 kW, składających się z przekształtników AC/DC i DC/DC. Zaprezentowane moduły zostały opracowane i wdrożone przez firmę Zakład Energoelektroniki Twerd Sp. z o.o. jako moduły szybkiego ładowania pojazdów elektrycznych zapewniające separację galwaniczną między obwodami AC i DC poprzez wysokoczęstotliwościowy transformator. Pierwszy z modułów wykonany jest w tradycyjnej technologii krzemowej (tranzystory IGBT) i topologii umożliwiającej jednokierunkowy przesył energii. Drugi moduł w swojej konstrukcji wykorzystuje tranzystory mocy z węglika krzemu (SiC) i umożliwia dwukierunkowy transfer energii. W artykule przybliżono topologie analizowanych przekształtników oraz zaprezentowano eksperymentalne porównanie sprawności obu modułów współpracujących z baterią pojazdu elektrycznego.
EN
The article presents a comparison of the efficiency of 50 kW charger modules, consisting of AC/DC and DC/DC converters. The presented modules were developed and implemented by Zakład Energoelektroniki Twerd Sp. z o.o. as fast charging modules for electric vehicles ensuring galvanic separation between AC and DC circuits through a high-frequency transformer. The first module is made in traditional silicon technology (IGBT transistors) and a topology that enables unidirectional energy transfer. The second module uses silicon carbide (SiC) power transistors in its design and enables bi-directional energy transfer. The article presents the topologies of the analyzed converters and presents an experimental comparison of the efficiency of both modules cooperating with the electric vehicle battery.
8
Content available Numerical analysis of the temperature impact to the oxygen distribution in the biological tissue
Jasiński Marek
Journal of Applied Mathematics and Computational Mechanics
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2020
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Vol. 19, nr 3
17--28
EN
The aim of the study was to analyze changes in tissue oxygen distribution resulting from temperature changes by the use of the Krogh cylinder model with Michaelis-Menten kinetics. A Hill model was also used to describe the oxyhemoglobin dissociation curve. In particular, variable values of parameters of dissociation curve and blood velocity in capillary were considered. Mathematical description was based on two separate equations for radial and axial directions. An additional task related to determination of the temperature, tissue thermal damage and perfusion was also solved. At the stage of numerical realization, the finite difference method was used.
9
Content available Modelling of biological tissue damage process with application of interval arithmetic
Korczak Anna, Jasiński Marek
Journal of Theoretical and Applied Mechanics
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2019
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Vol. 57 nr 1
249--261
EN
In the paper, the numerical analysis of thermal processes proceeding in a 2D soft biological tissue subjected to laser irradiation is presented. The transient heat transfer is described by the bioheat transfer equation in Pennes formulation. The internal heat source resulting from the laser-tissue interaction based on the solution of the diffusion equation is taken into account. Thermophysical and optical parameters of the tissue are assumed as directed intervals numbers. At the stage of numerical realization. the interval finite difference method has been applied. In the final part of the paper, the results obtained are shown.
10
Content available Effect of dissection on the mechanical properties of human ascending aorta and human ascending aorta aneurysm
Kozuń Marta, Płonek Tomasz, Jasiński Marek, Filipiak Jarosław
Acta of Bioengineering and Biomechanics
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2019
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Vol. 21, no. 2
127--134
EN
The aim of the presented work is to determine (i) mechanical properties of the ascending aorta wall (DAA) and the wall of the ascending aortic aneurysm (DAAA), in which spontaneous dissection resulting from the evolving disease occurred, and (ii) the strength of the interface between the layers in the above-mentioned vessels. Methods: The mechanical tests were divided into two steps. In the first step the mechanical properties of the of DAA and DAAA walls were examined on the basis of uniaxial stretching until rapture. In the next step the mechanical parameters of the interface between layers of DAA and DAAA walls were determined by the peeling test. Results: Higher values of tensile strength (max) and Young’s modulus (E) were obtained for the DAAA group, to which the dissecting wall of the ascending aortic aneurysm was classified. For circumferential samples, the difference between the DAAA and DAA groups was 39% in the case of tensile strength and 70% in the case of the Young’s modulus. Conclusions: Summarizing, the studies performed showed that the dissection process is different in the case of the ascending aortic aneurysm wall and the ascending aorta wall. The wall of the ascending aortic aneurysm is more susceptible to dissection, as evidenced by lower values of the mechanical parameters of the interface between the intima and the media-adventitia complex. The obtained results of mechanical properties tests confirm that dissection and aneurysm should be treated as separate disease entities that may coexist with each other.
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