Publications reported by three months

1.Zawidzki M., Szklarski J., Effective Multi-objective Discrete Optimization of Truss-Z Layouts Using a GPU, APPLIED SOFT COMPUTING, ISSN: 1568-4946, DOI: 10.1016/j.asoc.2018.05.042, pp.1-22, 2018
Zawidzki M., Szklarski J., Effective Multi-objective Discrete Optimization of Truss-Z Layouts Using a GPU, APPLIED SOFT COMPUTING, ISSN: 1568-4946, DOI: 10.1016/j.asoc.2018.05.042, pp.1-22, 2018

Abstract:
Truss-Z (TZ) is an Extremely Modular System for creating skeletal free-form ramps and ramp networks. The TZ structures are comprised of four variations of two types of basic unit subjected to rotation. The two types of units are: R and L being a mirror reflection of each other. This paper presents a novel method based on image processing, evolutionary algorithm and intensive parallelization of multi-objective optimization of TZ layouts.

The algorithm returns a sequence of modules. The result guarantees a TZ connection between two given points (regions) and minimizes the fitness function representing certain costs associated with setting up the TZ structure.

The fitness function depends on the cost of TZ structure as well as the variety of costs related to the environment where the it is to be placed. E.g.: the earthworks, vegetation removal, obstacles avoidance, etc. There are no restrictions on the fitness function definition. It can depend on any variable which can be represented by a two-dimensional map of any property of the environment.

The formulation of the presented method is suited for application of well-established image processing methods which efficiently evaluate candidate solutions on a GPU. As a result, the employed genetic algorithm efficiently probes the search space. The practical applicability of this approach is demonstrated with three case-studies:

1) simultaneous paving of a path with congruent units in a hilly environment with trees & bushes and finding the best location for a pier over an existing river;

2) constructing of a TZ connector spanning over a mountain valley with lakes (where supports can not be placed);

3) retrofitting of an existing railway station with a large wheelchair TZ ramp of over 10 m elevation while preserving trees and minimizing the earthworks.

Keywords:
Truss-Z, Extremely Modular System, Retrofitting, accessibility, multi-objective, discrete, combinatorial, optimization, genetic algorithm, parallel computing, GPU, GPGPU

2.Rydzek G., Pakdel A., Witecka A., Shri D.N.A., Gaudière F., Nicolosi V., Mokarian-Tabari P., Schaaf P., Boulmedais F., Ariga K., pH-Responsive Saloplastics Based on Weak Polyelectrolytes: From Molecular Processes to Material Scale Properties, Macromolecules, ISSN: 0024-9297, DOI: 10.1021/acs.macromol.8b00609, Vol.51, No.12, pp.4424-4434, 2018
Rydzek G., Pakdel A., Witecka A., Shri D.N.A., Gaudière F., Nicolosi V., Mokarian-Tabari P., Schaaf P., Boulmedais F., Ariga K., pH-Responsive Saloplastics Based on Weak Polyelectrolytes: From Molecular Processes to Material Scale Properties, Macromolecules, ISSN: 0024-9297, DOI: 10.1021/acs.macromol.8b00609, Vol.51, No.12, pp.4424-4434, 2018

Abstract:
Compact polyelectrolyte complexes (COPECs), also named saloplastics, represent a new class of material with high fracture strain and self-healing properties. Here, COPECs based on poly(methacrylic acid) (PMAA) and poly(allylamine hydrochloride) (PAH) were prepared by centrifugation at pH 7. The influence of postassembly pH changes was monitored chemically by ATR-FTIR, ICP, DSC, and TGA, morphologically by SEM, and mechanically by strain to break measurements. Postassembly pH stimuli misbalanced the charge ratio in COPECs, impacting their concentration in counterions, cross-link density, and polymer chain mobility. At the material level, changes were observed in the porosity, composition, water content, and mechanical properties of COPECs. The cross-link density was a prominent factor governing the saloplastic’s composition and water content. However, the porosity and mechanical properties were driven by several factors including salt-induced plasticization and conformational changes of polyelectrolytes. This work illustrates how multiple-scale consequences arise from a single change in the environment of COPECs, providing insights for future design of stimuli-responsive materials.

3.Lanzi M., Salatelli E., Giorgini L., Marinelli M., Pierini F., Effect of the incorporation of an Ag nanoparticle interlayer on the photovoltaic performance of green bulk heterojunction water-soluble polythiophene solar cells, POLYMER, ISSN: 0032-3861, DOI: 10.1016/j.polymer.2018.07.012, Vol.149, pp.273-285, 2018
Lanzi M., Salatelli E., Giorgini L., Marinelli M., Pierini F., Effect of the incorporation of an Ag nanoparticle interlayer on the photovoltaic performance of green bulk heterojunction water-soluble polythiophene solar cells, POLYMER, ISSN: 0032-3861, DOI: 10.1016/j.polymer.2018.07.012, Vol.149, pp.273-285, 2018

Abstract:
Two water-soluble regioregular poly(3-alkylthiophene)s, incorporating aminic groups at the end of the side chains, have been synthesized using a post-polymerization functionalization procedure on a ω-bromine substituted polyalkylthiophene. The high solubility of the obtained polymers in water allowed for the preparation of “green” bulk heterojunction solar cells which reached a power conversion efficiency of 4.85% when PC61BM was used as electron-acceptor material. Improved optical absorption and photocurrent have been obtained by interposing a layer of Ag nanoparticles between the buffer and the photoactive layer, leading to a final power conversion efficiency of 5.51%.

Keywords:
Water-soluble polythiophene, Bulk heterojunction solar cell, Organic photovoltaic

4.Bukowicki M., Ekiel-Jeżewska M.L., Different bending models predict different dynamics of sedimenting elastic trumbbells, SOFT MATTER, ISSN: 1744-683X, DOI: 10.1039/C8SM00604K, Vol.14, pp.5786-5799, 2018
Bukowicki M., Ekiel-Jeżewska M.L., Different bending models predict different dynamics of sedimenting elastic trumbbells, SOFT MATTER, ISSN: 1744-683X, DOI: 10.1039/C8SM00604K, Vol.14, pp.5786-5799, 2018

Abstract:
The main goal of this paper is to examine theoretically and numerically the impact of a chosen bending model on the dynamics of elastic filaments settling in a viscous fluid under gravity at low-Reynolds-number. We use the bead-spring approximation of a filament and the Rotne–Prager mobility matrix to describe hydrodynamic interactions between the beads. We analyze the dynamics of trumbbells, for which bending angles are typically larger than for thin and long filaments. Each trumbbell is made of three beads connected by springs and it exhibits a bending resistance, described by the harmonic or – alternatively – by the ‘cosine’ (also called the Kratky–Porod) bending models, both often used in the literature. Using the harmonic bending potential, and coupling it to the spring potential by the Young's modulus, we find simple benchmark solutions: stable stationary configurations of a single elastic trumbbell and attraction of two elastic trumbbells towards a periodic long-lasting orbit. As the most significant result of this paper, we show that for very elastic trumbbells at the same initial conditions, the Kratky–Porod bending potential can lead to qualitatively and quantitatively different spurious dynamics, with artificially large bending angles and unrealistic shapes. We point out that for the bead models of an elastic filament, the range of applicability of the Kratky–Porod model might not go beyond bending angles smaller than π/2 for touching beads and beyond an even much lower value for beads well-separated from each other. The existence of stable stationary configurations of elastic trumbbells and a family of periodic oscillations of two elastic trumbbells are very important findings on their own.

5.Dulnik J., Kołbuk D., Denis P., Sajkiewicz P., The effect of a solvent on cellular response to PCL/gelatin and PCL/collagen electrospun nanofibres, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2018.05.010, Vol.104, pp.147-156, 2018
Dulnik J., Kołbuk D., Denis P., Sajkiewicz P., The effect of a solvent on cellular response to PCL/gelatin and PCL/collagen electrospun nanofibres, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2018.05.010, Vol.104, pp.147-156, 2018

Abstract:
Bicomponent polycaprolactone/gelatin and polycaprolactone/collagen fibres were formed by electrospinning using two kinds of solvents: a representative of commonly used solvents with this polymer composition, highly toxic hexafluoroisopropanol (HFIP) and alternative, less harmful one, the mixture of acetic (AA) and formic (FA) acids. Both material types were subjected to investigations of structure and in-vitro cellular activity. Viscosity and Fourier transform infrared spectroscopy (FTIR) measurements shown that the type of solvent used influences the structure of solution and conformation of polymer molecules. In-vitro quantitative tests as well as cell culture morphology observations proved that materials electrospun with the use of ‘green’ solvents can yield similar results to those obtained by made with toxic ones. Slightly better cellular response to materials electrospun from HFIP can be explained by relatively well dispersed components within the fibre and more expanded conformation of molecules, resulting in better exposition of RGD (Arg-Gly-Asp) binding sites to cells’ integrin receptors.

Keywords:
Cellular tests, Electrospinning, Biopolymers, Viscosity, Solvents

6.Jeznach O., Kołbuk D., Sajkiewicz P., Injectable hydrogels and nanocomposite hydrogels for cartilage regeneration, Journal of Biomedical Materials Research Part A, ISSN: 1549-3296, DOI: 10.1002/jbm.a.36449, pp.1-51, 2018
Jeznach O., Kołbuk D., Sajkiewicz P., Injectable hydrogels and nanocomposite hydrogels for cartilage regeneration, Journal of Biomedical Materials Research Part A, ISSN: 1549-3296, DOI: 10.1002/jbm.a.36449, pp.1-51, 2018

Abstract:
Cartilage loss due to age‐related degeneration and mechanical trauma is a significant and challenging problem in the field of surgical medicine. Unfortunately, cartilage tissue can be characterized by the lack of regenerative ability. Limitations of conventional treatment strategies, such as auto‐, allo‐ and xenografts or implants stimulate an increasing interest in the tissue engineering approach to cartilage repair. This review discusses the application of polymer‐based scaffolds, with an emphasis on hydrogels in cartilage tissue engineering. We highlight injectable hydrogels with various micro‐ and nanoparticles, as they constitute a novel and attractive type of scaffolds. We discuss advantages, limitations and future perspectives of injectable nanocomposite hydrogels for cartilage tissue regeneration.

Keywords:
polymers, hydrogels, injectable hydrogels, injectable nanocomposite hydrogels, cartilage repair, cartilage tissue engineering

7.Postek E., Sadowski T., Distributed microcracking process of WC/Co cermet under dynamic impulse compressive loading , COMPOSITE STRUCTURES, ISSN: 0263-8223, DOI: 10.1016/j.compstruct.2018.04.014, Vol.194, pp.494-508, 2018
Postek E., Sadowski T., Distributed microcracking process of WC/Co cermet under dynamic impulse compressive loading , COMPOSITE STRUCTURES, ISSN: 0263-8223, DOI: 10.1016/j.compstruct.2018.04.014, Vol.194, pp.494-508, 2018

Abstract:
Cermet Materials (CM), for example, WC/Co, have very good mechanical, thermal and wear properties. They are used for manufacturing of cutting tools. However, their behavior under dynamic loads is still not properly understood.
Experiments, e.g. Siegl and Fischmester (1988) and Ravichandran (1994), indicate that the fracture energy of
WC/Co is expended through ductile failure of the Co: (1) close to the binder/tungsten carbide interface (Liu et al., 2017) [64] or by (2) dimple rupture across the interphase (Sigl and Exner, 1987) [22]. Stress concentrations around grain boundaries lead to initiation of microcracks which are dispersed by dynamic loading.
The main goal of the paper is to investigate the previously formulated models of the two-phase composite (Sadowski et al., 2005, 2006, 2007; Dębski and Sadowski, 2014, 2017) [47–51] in the case of dynamic compressive
pulses that are common in the case of cutting tools. We have taken into account complex spatial distribution of cermet phases, grain/binder interfaces modeled by interface elements, possibility of cracks appearance within binders using interface elements as well, and rotation of brittle grains.
The obtained results show that microcracking process and stress distributions are different for quasi-static and dynamic loadings. Early development of microcracks distribution revealed by damage parameter was observed.

Keywords:
Cermet, Dynamic compressive impulse, Interface elements, Distributed microcracking process

8.Vakis A.I., Yastrebov V.A., Scheibert J., Nicola L., Dini D., Minfray C., Almqvist A., Paggi M., Lee S., Limbert G., Molinari J.F., Anciaux G., Aghababaei R., Echeverri Restrepo S., Papangelo A., Cammarata A., Nicolini P., Putignano C., Carbone G., Stupkiewicz S., Lengiewicz J., Costagliola G., Bosia F., Guarino R., Pugno N.M., Müser M.H., Ciavarella M., Modeling and simulation in tribology across scales: An overview, TRIBOLOGY INTERNATIONAL, ISSN: 0301-679X, DOI: 10.1016/j.triboint.2018.02.005, Vol.125, pp.169-199, 2018
Vakis A.I., Yastrebov V.A., Scheibert J., Nicola L., Dini D., Minfray C., Almqvist A., Paggi M., Lee S., Limbert G., Molinari J.F., Anciaux G., Aghababaei R., Echeverri Restrepo S., Papangelo A., Cammarata A., Nicolini P., Putignano C., Carbone G., Stupkiewicz S., Lengiewicz J., Costagliola G., Bosia F., Guarino R., Pugno N.M., Müser M.H., Ciavarella M., Modeling and simulation in tribology across scales: An overview, TRIBOLOGY INTERNATIONAL, ISSN: 0301-679X, DOI: 10.1016/j.triboint.2018.02.005, Vol.125, pp.169-199, 2018

Abstract:
This review summarizes recent advances in the area of tribology based on the outcome of a Lorentz Center workshop surveying various physical, chemical and mechanical phenomena across scales. Among the main themes discussed were those of rough surface representations, the breakdown of continuum theories at the nano- and microscales, as well as multiscale and multiphysics aspects for analytical and computational models relevant to applications spanning a variety of sectors, from automotive to biotribology and nanotechnology. Significant effort is still required to account for complementary nonlinear effects of plasticity, adhesion, friction, wear, lubrication and surface chemistry in tribological models. For each topic, we propose some research directions.

Keywords:
Tribology, Multiscale modeling, Multiphysics modeling, Roughness, Contact, Friction, Adhesion, Wear, Lubrication, Tribochemistry

9.Nowicki A., Trawiński Z., Gambin B., Secomski W., Szubielski M., Parol M., Olszewski R., 20-MHZ ULTRASOUND FOR MEASUREMENTS OFFLOW-MEDIATED DILATION AND SHEAR RATE IN THE RADIALARTERY , ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/j.ultrasmedbio.2018.02.011, Vol.44, No.6, pp.1187-1197, 2018
Nowicki A., Trawiński Z., Gambin B., Secomski W., Szubielski M., Parol M., Olszewski R., 20-MHZ ULTRASOUND FOR MEASUREMENTS OFFLOW-MEDIATED DILATION AND SHEAR RATE IN THE RADIALARTERY , ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/j.ultrasmedbio.2018.02.011, Vol.44, No.6, pp.1187-1197, 2018

Abstract:
A high-frequency scanning system consisting of a 20-MHz linear array transducer combined with a 20-MHz pulsed Dopplerprobe was introduced to evaluate the degree of radial artery flow-mediated dilation (FMD [%]) in two groups of patients after5 min of controlled forearm ischemia followed by reactive hyperemia. In group I, comprising 27 healthy volunteers, FMD (mean ± standard deviation) was 15.26 ± 4.90% (95% confidence interval [CI]: 13.32%–17.20%); in group II, comprising 17 patients with chronic coronary artery disease, FMD was significantly less at 4.53 ± 4.11% (95% CI: 2.42%–6.64%). Specifically, the ratio FMD/SR (mean ± standard deviation),wasequalto5.36×10−4±4.64×10−4 (95%CI:3.54×10−4 to7.18×10−4)ingroupIand1.38×10−4±0.89×10−4 (95% CI: 0.70 × 10−4 to 2.06 × 10−4) in group II. Statistically significant differences between the two groups were confirmed by a Wilcoxon–Mann–Whitney test for both FMD and FMD/SR (p < 0.01). Areas under receiver operating characteristic curves for FMD and FMD/SR were greater than 0.9. The results confirm the usefulness of the proposed measurements of radial artery FMD and SR in differentiation of normal patients from those with chronic coronary artery disease. (E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. ) © 2018 World Federation for Ultrasound in Medicine & Biology. All rights reserved.

Keywords:
Flow-mediated vasodilation, Radial artery, Shear rate, Reactive hyperemia, Endothelium, Pulsed doppler, Ultrasonography

10.Jarząbek D.M., The impact of weak interfacial bonding strength on mechanical properties of metal matrix - ceramic reinforced composites, COMPOSITE STRUCTURES, ISSN: 0263-8223, DOI: 10.1016/j.compstruct.2018.06.071, Vol.201, pp.352-362, 2018
Jarząbek D.M., The impact of weak interfacial bonding strength on mechanical properties of metal matrix - ceramic reinforced composites, COMPOSITE STRUCTURES, ISSN: 0263-8223, DOI: 10.1016/j.compstruct.2018.06.071, Vol.201, pp.352-362, 2018

Abstract:
In this work the influence of weak interface between particles and matrix on mechanical properties of metal matrix – ceramic reinforced composites is studied. Firstly, the samples made of coelectrodeposited Ni-SiC composites with 10% of SiC with poor interface bonding have been prepared. Furthermore, the tensile tests of samples have been performed. The determined Young’s modulus was equal to 67 ± 8 GPa and the ultimate tensile strength to 230 ± 15 MPa. It is assumed that the very weak interface is the reason for the poor mechanical properties of the created material. In order to confirm the assumption and get the necessary parameters for the numerical model, the measurements of the normal and shear interfacial bonding strength of the interface have been performed. The measured normal interfacial bonding strength is equal to 0.1 ± 0.03 MPa and the interfacial shear strength is equal to 4.9 ± 0.2 MPa. The experimental results have been confirmed qualitatively by the computer simulations. Representative Volume Element has been created and modelled by the Finite Element Method with cohesive zone elements. The computer simulations result in the Young’s modulus values from 119 GPa up to 126 GPa.

Keywords:
Interfacial bonding strength, Metal matrix composites, Tensile strength, Silicon carbide, Electrodeposited nickel, Cohesive elements

11.Kubissa W., Glinicki M.A., Dąbrowski M., Permeability testing of radiation shielding concrete manufactured at industrial scale, MATERIALS AND STRUCTURES, ISSN: 1359-5997, DOI: 10.1617/s11527-018-1213-0, Vol.51, No.83, pp.1-15, 2018
Kubissa W., Glinicki M.A., Dąbrowski M., Permeability testing of radiation shielding concrete manufactured at industrial scale, MATERIALS AND STRUCTURES, ISSN: 1359-5997, DOI: 10.1617/s11527-018-1213-0, Vol.51, No.83, pp.1-15, 2018

Abstract:
The effect of the composition of industrial concrete designed for radiation shielding structures on the air permeability and the diffusion of moisture was studied. The mix design for heavyweight concrete of bulk density 3168–3317 kg/m3 was developed using barite and magnetite aggregate and cements blended with fly ash and blastfurnace slag. Structural elements, like columns of a height of 4 m and massive blocks made of mixtures with different cements were manufactured using ready mixed concrete pumped into the formwork. Core specimens were taken from the elements at different locations. The air permeability index was tested using Autoclam device. Evaluation of the quality of concrete on the basis of API results varied from “very good” to “good”. The moisture distribution inside concrete specimens was equilibrated to RH = 60 ± 5%. Observation of RH changes allowed to determine the moisture diffusion coefficient. Significant differences of the permeability and moisture diffusion coefficient depending on the location of the core specimens drilling and mix design of concrete were found. The D coefficient provided a good reflection of the different quality of heavyweight concrete in structural elements.

Keywords:
Air permeability, Autoclam, Barite, Blended cement, Cracking, Heavyweight aggregate, Magnetite, Moisture diffusion, Radiation shielding concrete, Relative humidity

12.Pakdel A., Witecka A., Rydzek G., Shri D.N.A., Nicolosi V., A comprehensive analysis of extrusion behavior, microstructural evolution, and mechanical properties of 6063 Al–B4C composites produced by semisolid stir casting, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2018.02.080, Vol.721, pp.28-37, 2018
Pakdel A., Witecka A., Rydzek G., Shri D.N.A., Nicolosi V., A comprehensive analysis of extrusion behavior, microstructural evolution, and mechanical properties of 6063 Al–B4C composites produced by semisolid stir casting, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, ISSN: 0921-5093, DOI: 10.1016/j.msea.2018.02.080, Vol.721, pp.28-37, 2018

Abstract:
In this study, composites of aluminum alloy 6063 reinforced with 10 wt% boron carbide microparticles were successfully fabricated by a combination of spark plasma sintering and stir casting methods, followed by hot extrusion. A systematic study on the relationship between extrusion process variables (i.e. extrusion ratio, temperature, and punch speed) and porosity, particle refinement, particle distribution and consequently tensile properties and fracture behavior of the composites was performed. Extensive electron microscopy analysis and tensile testing of the composites revealed a multifactoral interdependency of microstructural evolution and mechanical properties on the extrusion process variables. For example, while increasing the extrusion ratio at higher temperatures led to moderate particle refinement, better densification of the composites, and improvement in mechanical properties, concurrent particle fragmentation and microvoid formation around the particles at lower temperatures had opposing effects on the mechanical behavior. We show that the dependency of mechanical properties on all such microstructural factors makes it difficult to predict optimum extrusion conditions in aluminum matrix composites. That is, unlike the common approach, extruding the composites at higher temperatures and achieving more reduction in area may not necessarily lead to the most favorable mechanical properties.

Keywords:
Aluminum matrix composite, Hot extrusion, Mechanical behavior, Microstructure, Spark plasma sintering, Stir casting

13.Pisarski D., Konowrocki R., Szmidt T., Dynamics and optimal control of an electromagnetically actuated cantilever pipe conveying fluid, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2018.06.045, Vol.432, pp.420-436, 2018
Pisarski D., Konowrocki R., Szmidt T., Dynamics and optimal control of an electromagnetically actuated cantilever pipe conveying fluid, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2018.06.045, Vol.432, pp.420-436, 2018

Abstract:
This paper deals with the problem of applying electromagnetic devices of the motional type to improve the dynamic stability of a pipe conveying air. When the flow velocity reaches a critical value, the steady equilibrium position becomes unstable, and self-excited lateral vibrations arise. In contrast, electromagnetic devices of the transformer type have been demonstrated to be highly effective in the passive stabilization of such a system, as well as the active stabilization of similar non-conservative systems with a follower force. In the present paper, we apply a pair of motional devices made of a conducting plate which is attached to the pipe and moves together with it within the perpendicular magnetic field generated by the controlled electromagnets. This motion generates eddy currents in the plates and a drag force of a viscous character. In this setting, we first investigate the possibility of designing a stabilizing control within the region of the magnetic field where every passive solution results in an
unstable or conservative state. For that purpose, we determine a practical condition justifying the existence of a stabilizing control for a given set of system parameters. Later we pose and solve an optimal control problem aiming at stabilizing the system with the optimal rate of decrease of the system’s energy. The solution is examined by means of numerical simulations performed within the three regions of the flow velocity: low subcritical, where the Coriolis acceleration of the conveyed fluid generates the predominate damping force; high subcritical, where the inertia of the fluid begins to dominate the dynamics of the system; and low supercritical,where unstable flutter vibrations start to arise. The effectiveness of the designed optimal controller is validated by comparisons with the corresponding passive solutions.

Keywords:
fluid–structure interaction, electromagnetic device, optimal control, stabilization, smart structure

14.Postek E., Sadowski T., Dynamic pulse sensitivity of WC/Co composite, COMPOSITE STRUCTURES, ISSN: 0263-8223, DOI: 10.1016/j.compstruct.2017.10.092, No.203, pp.498-512, 2018
Postek E., Sadowski T., Dynamic pulse sensitivity of WC/Co composite, COMPOSITE STRUCTURES, ISSN: 0263-8223, DOI: 10.1016/j.compstruct.2017.10.092, No.203, pp.498-512, 2018

Abstract:
Cutting tools are manufactured among others from cermet (e.g. WC/Co) having excellent mechanical properties. Geometry of the internal microstructure is complex and mechanical response due to quasi-static or dynamic loading is difficult to be described. Particularly, the dynamic loading is not investigated enough precise up till now.
Experimental evidences, e.g. Siegl and Fischmester (1988), Ravichandran (1994), indicate that the fracture energy of WC/Co is expended through ductile failure of the Co: (1) near the binder/tungsten carbide interface or by (2) dimple rupture across the interphase. Concentrations of stresses around grain boundaries lead to initiation of microcrack system, which is dispersed for dynamic loading.
The aim of the paper is to extend the previously formulated models (Sadowski et al., 2005, 2006, 2007, Dębski and Sadowski, 2014, 2017) of the polycrystalline composite towards more advanced finite element formulation, applicable for description of the cermet behavior under dynamic pulses. The model takes into account: (1) spatial distribution of the cermet constituents, (2) system of grain boundaries/binder interfaces modeled by interface elements, (3) rotation of brittle grains.
The obtained results show that stress distributions and gradual microcracking processes are quite different for quasi-static and dynamic loadings. It was revealed by damage parameter indicating concentration of microcracks.

Keywords:
Metal-ceramic composite, Interface elements, Crack propagation, Dynamic loading,

15.Frydrych K., Kowalczyk-Gajewska K., Microstructure Evolution in Cold-Rolled Pure Titanium: Modeling by the Three-Scale Crystal Plasticity Approach Accounting for Twinning, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-018-4676-2, Vol.49, No.8, pp.3610-3623, 2018
Frydrych K., Kowalczyk-Gajewska K., Microstructure Evolution in Cold-Rolled Pure Titanium: Modeling by the Three-Scale Crystal Plasticity Approach Accounting for Twinning, METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, ISSN: 1073-5623, DOI: 10.1007/s11661-018-4676-2, Vol.49, No.8, pp.3610-3623, 2018

Abstract:
A three-scale crystal plasticity model is applied to simulate microstructure evolution in hcp titanium subjected to cold rolling. Crystallographic texture and misorientation angle development, as an indicator of grain refinement, are studied. The impact of twinning activity on both phenomena is accounted for by combining the original three-scale formulation with the probabilistic twin-volume consistent (PTVC) reorientation scheme. The modeling results are compared with available experimental data. It is shown that the simulated textures are in accordance with the experimental measurements. The basic components of misorientation angle distribution, especially in the range of high angle boundaries, are also well reproduced.

16.Niemczyk B., Sajkiewicz P.Ł., Kołbuk D., Injectable hydrogels as novel materials for central nervous system regeneration, Journal of neural engineering, ISSN: 1741-2560, DOI: 10.1088/1741-2552/aacbab, Vol.15, No.5, pp.051002-1-15, 2018
Niemczyk B., Sajkiewicz P.Ł., Kołbuk D., Injectable hydrogels as novel materials for central nervous system regeneration, Journal of neural engineering, ISSN: 1741-2560, DOI: 10.1088/1741-2552/aacbab, Vol.15, No.5, pp.051002-1-15, 2018

Abstract:
Approach. Injuries of the central nervous system (CNS) can cause serious and permanent disability due to limited regeneration ability of the CNS. Presently available therapies are focused on lesion spreading inhibition rather than on tissue regeneration. Recent investigations in the field of neural tissue engineering indicate extremely promising properties of novel injectable and non-injectable hydrogels which are tailored to serve as biodegradable scaffolds for CNS regeneration. Objective. This review discusses the state-of-the-art and barriers in application of novel polymer-based hydrogels without and with nanoparticles for CNS regeneration. Main results. Pure hydrogels suffer from lack of similarities to natural neural tissue. Many of the biological studies indicated nano-additives in hydrogels may improve their topography, mechanical properties, electroconductivity and biological functions. The most promising biomaterials which meet the requirements of CNS tissue engineering seem to be injectable thermosensitive hydrogels loaded with specific micro-and nanoparticles. Significance. We highlight injectable hydrogels with various micro-and nanoparticles, because of novelty and attractiveness of this type of materials for CNS regeneration and future development perspectives.

Keywords:
hydrogels, nanoparticles, injectable, microparticles, nanofibers, central nervous system

17.Żuk P.J., Kochańczyk M., Lipniacki T., Sampling rare events in stochastic reaction-diffusion systems within trajectory looping, PHYSICAL REVIEW E, ISSN: 1539-3755, DOI: 10.1103/PhysRevE.98.022401, Vol.98, pp.022401-1-022401-10, 2018
Żuk P.J., Kochańczyk M., Lipniacki T., Sampling rare events in stochastic reaction-diffusion systems within trajectory looping, PHYSICAL REVIEW E, ISSN: 1539-3755, DOI: 10.1103/PhysRevE.98.022401, Vol.98, pp.022401-1-022401-10, 2018

Abstract:
In bistable reaction–diffusion systems, transitions between stable states typically occur on timescales orders of magnitude longer than the chemical equilibration time. Estimation of transition rates within explicit Brownian dynamics simulations is computationally prohibitively costly. We present a method that exploits a single trajectory, generated by a prior simulation of diffusive motions of molecules, to sample chemical kinetic processes on timescales several orders of magnitude longer than the duration of the diffusive trajectory. In this approach, we “loop” the diffusive trajectory by transferring chemical states of the molecules from the last to the first time step of the trajectory. Trajectory looping can be applied to enhance sampling of rare events in biochemical systems in which the number of reacting molecules is constant, as in cellular signal transduction pathways. As an example, we consider a bistable system of autophosphorylating kinases, for which we calculate state-to-state transition rates and traveling wave velocities. We provide an open-source implementation of the method.

18.Postek E., Sadowski T., Qualitative comparison of dynamic compressive pressure load and impact of WC/Co composite, International Journal of Refractory Metals and Hard Materials, ISSN: 0263-4368, DOI: 10.1016/j.ijrmhm.2018.07.009, Vol.77, pp.68-81, 2018
Postek E., Sadowski T., Qualitative comparison of dynamic compressive pressure load and impact of WC/Co composite, International Journal of Refractory Metals and Hard Materials, ISSN: 0263-4368, DOI: 10.1016/j.ijrmhm.2018.07.009, Vol.77, pp.68-81, 2018

Abstract:
Degradation of Cermet Materials (CM) under impact and pulse pressure is not thoroughly investigated. In this
study, we qualitatively compare the behaviour of WC/Co samples under these types of loading.
The new models of impact and dynamic compressive load of a WC/Co plate were investigated. We developed two models of the composite plate, namely, a continuous model and a model with crack appearance possibility in the interfaces/binders.
We noted a qualitative difference of the shapes of the deformed structure due to different models and kind of loading. The differences also concern the Mises stress, equivalent plastic strains and damage parameter.
The proposed models are suitable for both impact and pressure load. The possibility of cracks appearance should not be neglected. In case of the model with discontinuities, for both kinds of loads, the grains rotation and sliding is more distinct than in case of the continuous model.

Keywords:
Cermet, Impact, Pressure load, Interface elements, Distributed microcracking process, Numerical models

19.Frydrych K., Kowalczyk-Gajewska K., Grain refinement in the equal channel angular pressing process: simulations using the crystal plasticity finite element method, MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, ISSN: 0965-0393, DOI: 10.1088/1361-651X/aad46d, Vol.26, No.6, pp.065015-1-065015-32, 2018
Frydrych K., Kowalczyk-Gajewska K., Grain refinement in the equal channel angular pressing process: simulations using the crystal plasticity finite element method, MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, ISSN: 0965-0393, DOI: 10.1088/1361-651X/aad46d, Vol.26, No.6, pp.065015-1-065015-32, 2018

Abstract:
Grain refinement due to severe plastic deformation is simulated using the crystal plasticity finite element method in the total Lagrangian setting. A rate-independent model with the regularized Schmid law is applied. As an example, a single pass of the equal channel angular pressing process is considered. Texture evolution, misorientation angle distributions and maps of new grains are presented. A special algorithm for tracking the creation of new grains in finite element simulations is developed. The results are analysed with respect to experimental data available in the literature. The possible mechanisms leading to the fragmentation of grains in a face centred cubic material are discussed. The influence of the quality of the microstructure representation on the simulation results is assessed

Keywords:
crystal plasticity, severe plastic deformation, grain refinement, finite element method

20.Skłodowska K., Dębski P.R., Michalski J.A., Korczyk P.M., Dolata M., Zając M., Jakiela S., Simultaneous Measurement of Viscosity and Optical Density of Bacterial Growth and Death in a Microdroplet, Micromachines, ISSN: 2072-666X, DOI: 10.3390/mi9050251, Vol.9, No.5, pp.1-13, 2018
Skłodowska K., Dębski P.R., Michalski J.A., Korczyk P.M., Dolata M., Zając M., Jakiela S., Simultaneous Measurement of Viscosity and Optical Density of Bacterial Growth and Death in a Microdroplet, Micromachines, ISSN: 2072-666X, DOI: 10.3390/mi9050251, Vol.9, No.5, pp.1-13, 2018

Abstract:
Herein, we describe a novel method for the assessment of droplet viscosity moving inside microfluidic channels. The method allows for the monitoring of the rate of the continuous growth of bacterial culture. It is based on the analysis of the hydrodynamic resistance of a droplet that is present in a microfluidic channel, which affects its motion. As a result, we were able to observe and quantify the change in the viscosity of the dispersed phase that is caused by the increasing population of interacting bacteria inside a size-limited system. The technique allows for finding the correlation between the viscosity of the medium with a bacterial culture and its optical density. These features, together with the high precision of the measurement, make our viscometer a promising tool for various experiments in the field of analytical chemistry and microbiology, where the rigorous control of the conditions of the reaction and the monitoring of the size of bacterial culture are vital.

Keywords:
droplet microfluidics, cell growth, viscosity, rheology, Escherichia coli

21.Zawidzki M., Jankowski Ł., Optimization of modular Truss-Z by minimum-mass design under equivalent stress constraint, SMART STRUCTURES AND SYSTEMS, ISSN: 1738-1584, DOI: 10.12989/sss.2018.21.6.715, Vol.21, No.6, pp.715-725, 2018
Zawidzki M., Jankowski Ł., Optimization of modular Truss-Z by minimum-mass design under equivalent stress constraint, SMART STRUCTURES AND SYSTEMS, ISSN: 1738-1584, DOI: 10.12989/sss.2018.21.6.715, Vol.21, No.6, pp.715-725, 2018

Abstract:
Truss-Z (TZ) is an Extremely Modular System (EMS). Such systems allow for creation of structurally sound free-form structures, are comprised of as few types of modules as possible, and are not constrained by a regular tessellation of space. Their objective is to create spatial structures in given environments connecting given terminals without self-intersections and obstacle-intersections. TZ is a skeletal modular system for creating free-form pedestrian ramps and ramp networks. The previous research on TZ focused on global discrete geometric optimization of the spatial configuration of modules. This paper reports on the first attempts at structural optimization of the module for a single-branch TZ. The internal topology and the sizing of module beams are subject to optimization. An important challenge is that the module is to be universal: it must be designed for the worst case scenario, as defined by the module position within a TZ branch and the geometric configuration of the branch itself. There are four variations of each module, and the number of unique TZ configurations grows exponentially with the branch length. The aim is to obtain minimum-mass modules with the von Mises equivalent stress constrained under certain design load. The resulting modules are further evaluated also in terms of the typical structural criterion of compliance.

Keywords:
Extremely Modular System, Truss-Z, structural optimization, modular structures, minimum mass design, frame structures

22.Maździarz M., Rojek J., Nosewicz S., Molecular dynamics study of self-diffusion in stoichiometric B2-NiAl crystals, Philosophical Magazine, ISSN: 1478-6435, DOI: 10.1080/14786435.2018.1480838, Vol.98, No.24, pp.2257-2274, 2018
Maździarz M., Rojek J., Nosewicz S., Molecular dynamics study of self-diffusion in stoichiometric B2-NiAl crystals, Philosophical Magazine, ISSN: 1478-6435, DOI: 10.1080/14786435.2018.1480838, Vol.98, No.24, pp.2257-2274, 2018

Abstract:
Self-diffusion parameters in stoichiometric B2-NiAl solid state crystals were estimated by molecular statics/dynamics simulations with the study of required simulation time to stabilise diffusivity results. An extrapolation procedure to improve the diffusion simulation results was proposed. Calculations of volume diffusivity for the B2 type NiAl in the 1224–1699 K temperature range were performed using the embedded-atom-model potential. The results obtained here are in much better agreement with the experimental results than the theoretical estimates obtained with other methods.

Keywords:
NiAl; nickel–aluminium; diffusivity; molecular dynamics; molecular statics; embedded-atom method; sintering

23.Sławianowski J.J., Kovalchuk V., Gołubowska B., Martens A., Rożko E.E., Space‐time as a structured relativistic continuum, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, ISSN: 0170-4214, DOI: 10.1002/mma.5087, pp.1-19, 2018
Sławianowski J.J., Kovalchuk V., Gołubowska B., Martens A., Rożko E.E., Space‐time as a structured relativistic continuum, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, ISSN: 0170-4214, DOI: 10.1002/mma.5087, pp.1-19, 2018

Abstract:
There are various models of gravitation: the metrical Hilbert‐Einstein theory, a wide class of intrinsically Lorentz‐invariant tetrad theories (generally covariant in the space‐time sense), and many gauge models based on various internal symmetry groups (Lorentz, Poincare, GL(n,R), SU(2,2), GL(4,C), etc). The gauge models are usually preferred but nevertheless it is an interesting idea to develop the class of GL(4,R)‐invariant (or rather GL(n,R)‐invariant) tetrad (n‐leg) generally covariant models. This is done below and motivated by our idea of bringing back to life the Thales of Miletus concept of affine symmetry. Formally, the obtained scheme is a generally covariant tetrad (n‐leg) model, but it turns out that generally covariant and intrinsically affinely invariant models must have a kind of nonaccidental Born‐Infeld‐like structure. Let us also mention that they, being based on tetrads (n‐legs), have many features common with continuous defect theories. It is interesting that they possess some group‐theoretical solutions and more general spherically symmetric solutions, discussion of which is the main new result presented in this paper, including the applications of the 't Hooft‐Polyakov monopoles in the generally covariant theories, which enables us to find some rigorous solutions of our strongly nonlinear equations. It is also interesting that within such a framework, the normal‐hyperbolic signature of the space‐time metric is not introduced by hand but appears as a kind of solution, rather integration constants, of differential equations. Let us mention that our Born‐Infeld scheme is more general than alternative tetrad models. It may be also used within more general schemes, including also the gauge ones.

Keywords:
micromorphic medium, modified gravity, relativistic continuum, spherically symmetric solutions, theory of fundamental interactions.

24.Urbanek O., Kołbuk D., Wróbel M., Articular cartilage: New directions and barriers of scaffolds development– review, International Journal of Polymeric Materials and Polymeric Biomaterials, ISSN: 0091-4037, DOI: 10.1080/00914037.2018.1452224, pp.1-16, 2018
Urbanek O., Kołbuk D., Wróbel M., Articular cartilage: New directions and barriers of scaffolds development– review, International Journal of Polymeric Materials and Polymeric Biomaterials, ISSN: 0091-4037, DOI: 10.1080/00914037.2018.1452224, pp.1-16, 2018

Abstract:
Despite progress which has been made in recent years in the field of cell-based therapies or cell scaffolds for cartilage regeneration, a lot of work still needs to be done. Scaffolds remain a great base for tissue regeneration. However, proper implantation procedures or post-treatment still await development.

In this review we summarize paths of cartilage treatment, especially focusing on cell scaffold design and manufacture. As well as the advantages and disadvantages of available or investigated methods and materials, especially focusing on cartilage scaffold design. We show the most promising directions and barriers in the creation of healthy tissue.

Keywords:
Cartilage regeneration, medical devices, scaffold development, tissue engineering

25.Wojnar R., KINETIC EQUATION FOR THE DILUTE BOLTZMANN GAS IN AN EXTERNAL FIELD, ACTA PHYSICA POLONICA B, ISSN: 0587-4254, DOI: 10.5506/APhysPolB.49.905, Vol.49, No.5, pp.905-920, 2018
Wojnar R., KINETIC EQUATION FOR THE DILUTE BOLTZMANN GAS IN AN EXTERNAL FIELD, ACTA PHYSICA POLONICA B, ISSN: 0587-4254, DOI: 10.5506/APhysPolB.49.905, Vol.49, No.5, pp.905-920, 2018

Abstract:
We report a kinetic equation for an auxiliary distribution function f(k,v1,t) which yields the intermediate scattering function Is(k,t). To this end, the projection operator proposed by Stecki was applied. The scattering operator was given in explicit form in the limit of low density gas. The general kinetic equation was next specialized for the case of Lorentz gas.

26.Żurek Z.H., Kukla D., LDC1000 converter for NDT material diagnostics and characterisation, INSIGHT, ISSN: 1354-2575, DOI: 10.1784/insi.2018.60.7.375, Vol.60, No.7, pp.375-379, 2018
Żurek Z.H., Kukla D., LDC1000 converter for NDT material diagnostics and characterisation, INSIGHT, ISSN: 1354-2575, DOI: 10.1784/insi.2018.60.7.375, Vol.60, No.7, pp.375-379, 2018

Abstract:
The LDC1000 module[1,2] measurement tool is a commercial inductive converter made by Texas Instruments (TI). It has been designed to measure the distance to a surface from a given point above the surface of conducting materials. However, its design and software make it possible to use the device in many other innovative applications, such as in machine diagnostics (the measurement of shaft torsions and the detection and measurement of unbalance in rotating masses) and in the non-destructive testing (NDT) of continuity, shape and structural flaws. Examples of the application of this converter to flaw crack detection, to the measurement of electrical and magnetic parameters and to distance determination from a point above the surface to the surface of conducting materials, as well as to the estimation of the thickness of a non-conductive layer on a conductive surface, are described in this paper. The LDC1000 converter has been available commercially for a few years and its basic scope of application is expanding all of the time[4,5]. It has also been the subject matter for some PhD theses[6]. The principles for measuring the components of the normalised impedance are explained in the initial part of this paper, which is necessary in order to gain a full understanding of the converter operation. The LDC1000 converter operates in the current resonance region (resonance takes place between the inductive coil and the tested material). From the manifold diagnostic possibilities of the converter, its application in flaw detection will be presented in this paper. Crack detection and conductivity and distance measurements have been carried out and the local circuit inductance has been recorded. Measurements have been conducted with the standard flaw detection probe and the time required for performing repeatability measurements has also been investigated.

27.Błachowski B., Pnevmatikos N., Neural network based vibration control of seismically excited civil structures, Periodica Polytechnica Civil Engineering, ISSN: 0553-6626, DOI: 10.3311/PPci.11601, Vol.62, No.3, pp.620-628, 2018
Błachowski B., Pnevmatikos N., Neural network based vibration control of seismically excited civil structures, Periodica Polytechnica Civil Engineering, ISSN: 0553-6626, DOI: 10.3311/PPci.11601, Vol.62, No.3, pp.620-628, 2018

Abstract:
This study proposes a neural network based vibration control system designed to attenuate structural vibrations induced by an earthquake. Classical feedback control algorithms are susceptible to parameter changes. For structures with uncertain parameters they can even cause instability problems. The proposed neural network based control system can identify the structural properties of the system and avoids the above mentioned problems. In the present study it is assumed that a full state of the structure is known, which means the at each floor horizontal displacements and rotations about the vertical axis are measured. Additionally, it is assumed the acceleration signal coming from the earthquake is also available. The proposed neural control strategy is compared with the classical linear quadratic regulator (LQR) not only in terms of displacement responses, but also required control forces. Moreover, the influence of different weighting matrices on performance of the proposed control strategy has been presented.
The effectiveness of the neuro-controller has been demonstrated on two numerical examples: a simple single degree of freedom (DOF) structure and a multi-DOF structure representing a twelve story building. Both structures under consideration have been excited with El Centro acceleration signal. The results of numerical simulations on the SDOF system indicate that using neuro-controller it would be possible to obtain smaller amplitudes as compared with the LQ regulator, but it would require higher control effort.

Keywords:
vibration control, artificial neural networks, seismic excitation

28.Matsui R., Takeda K., Tobushi H., Pieczyska E.A., MECHANICAL PROPERTIES AND ADVANCED SUBJECTS IN SHAPE MEMORY ALLOYS AND POLYMERS, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, DOI: 10.15632/jtam-pl.56.2.447, Vol.56, No.2, pp.447-456, 2018
Matsui R., Takeda K., Tobushi H., Pieczyska E.A., MECHANICAL PROPERTIES AND ADVANCED SUBJECTS IN SHAPE MEMORY ALLOYS AND POLYMERS, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, DOI: 10.15632/jtam-pl.56.2.447, Vol.56, No.2, pp.447-456, 2018

Abstract:
Advanced subjects in mechanical properties of shape memory alloys and polymers are discussed. In the subloop loading under a stress-controlled condition of the shape memory alloy, the transformation-induced stress relaxation appears due to variation in temperature. The enhancement of corrosion and corrosion fatigue life of the shape memory alloy is discussed. The development of a functionally-graded shape memory alloy and polymer is expected to obtain better performance. Three-way motion appears in the shape memory composite with the shape memory alloy and polymer.

Keywords:
shape memory alloy, shape memory polymer, functionally-graded shape memory material, shape memory composite

29.Meissner M., A Novel Method for Determining Optimum Dimension Ratios for Small Rectangular Rooms, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/122369, Vol.43, No.2, pp.217-225, 2018
Meissner M., A Novel Method for Determining Optimum Dimension Ratios for Small Rectangular Rooms, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/122369, Vol.43, No.2, pp.217-225, 2018

Abstract:
A new method for determining optimum dimension ratios for small rectangular rooms has been presented. In a theoretical model, an exact description of the room impulse response was used. Based on the impulse response, a frequency response of a room was calculated to find changes in the sound pressure level over the frequency range 20-200 Hz. These changes depend on the source and receiver positions, thus, a new metric equivalent to an average frequency response was introduced to quantify the overall sound pressure variation within the room for a selected source position. A numerical procedure was employed to seek a minimum value of the deviation of the sound pressure level response from a smooth fitted response determined by the quadratic polynomial regression. The most smooth frequency responses were obtained when the source was located at one of the eight corners of a room. Thus, to find the best possible dimension ratios, in the numerical procedure the optimal source position was assumed. Calculation results have shown that optimum dimension ratios depend on the room volume and the sound damping inside a room, and for small and medium volumes these ratios are roughly 1:1.48:2.12, 1:1.4:1.89 and 1:1.2:1.45. When the room volume was suitably large, the ratio 1:1.2:1.44 was found to be the best one.

Keywords:
room acoustics, small rooms, optimum dimension ratios, room impulse response, frequency room response

30.Postek E., Sadowski T., Impact modelling of cerment composite, The 7th International Conference on Advanced Materials and Structures, 2018-03-28/03-31, Timisoara (RO), pp.111, 2018
31.Postek E., Generation of a tumor model, Supercomputing Frontiers Europe wraz z XX Sesją Sprawozdawczą Użytkowników KDM, 2018-03-12/03-16, ICM UW, Warszawa (PL), pp.1-1, 2018
Postek E., Generation of a tumor model, Supercomputing Frontiers Europe wraz z XX Sesją Sprawozdawczą Użytkowników KDM, 2018-03-12/03-16, ICM UW, Warszawa (PL), pp.1-1, 2018

Abstract:
The physical environment of living cells and tissues, and more
particularly their mechanical interaction with it, plays a crucial
regulatory role in their biological behaviour such as cell
differentiation, apoptosis, proliferation, tissue growth,
remodelling, tumor growth, etc. However, the way that
mechanical forces at the cellular level (i) influence the cell
functions and (ii) govern the behaviour of cell assemblies as well
as their development, remains unclear and hard to model.
First of all, we investigate a tissue growth model. The model is
generated with PhysiCell [1, 2].

Keywords:
computational biology, tumor growth

32.Chojnacki A., Konowrocki R., Analiza numeryczna i eksperymentalna bezpieczeństwa przed wykolejeniem pojazdu szynowego w oparciu o różne metody wyznaczania kryterium oceny, XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.8-9, 2018
Chojnacki A., Konowrocki R., Analiza numeryczna i eksperymentalna bezpieczeństwa przed wykolejeniem pojazdu szynowego w oparciu o różne metody wyznaczania kryterium oceny, XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.8-9, 2018

Abstract:
W artykule przedstawiono wyniki badań eksperymentalnych i numerycznych dotyczących zagadnień wykolejenia wagonu towarowego. Przybliżono charakteryzację stanu wiedzy dotyczącej metod oceny bezpieczeństwa pojazdów szynowych przed wykolejeniem, w celu ich porównania. W pracy przeprowadzono teoretyczne analizy porównawcze według kilku metod, które ocenią bezpieczeństwo przed wykolejeniem porównane z badaniami eksperymentalnymi. Na potrzeby analiz teoretycznych powstał numeryczny model układu pojazd szynowy-tor. Model ten uwzględniał parametry dynamiczne elementów zastosowanych w rzeczywistym pojeździe. Wyniki analizy teoretycznej poparto badaniami eksperymentalnymi przeprowadzonymi na rzeczywistym obiekcie (wagon towarowy - tor testowy). Uzyskane wyniki pozwoliły określić stan zagrożenia bezpieczeństwa ruchu wagonu towarowego przy różnych kryteriach oceny oraz je porównać.

Keywords:
współczynnik wykolejenia, dynamiki pojazdów szynowych, bezpieczeństwo, badania eksperymentalne

33.Zbieć A., Konowrocki R., Wpływ prac konserwacyjnych na zużycie kół zestawów kołowych wagonów towarowych , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.12-13, 2018
Zbieć A., Konowrocki R., Wpływ prac konserwacyjnych na zużycie kół zestawów kołowych wagonów towarowych , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.12-13, 2018

Abstract:
Artykuł dotyczy analizy nowo zdiagnozowanej przyczyny zużycia profili kół wagonu towarowego. W pracy przybliżono możliwe przyczyny nierównomiernego zużycia kół zestawów kołowych w wagonach towarowych znane z literatury, jak również podano nową hipotezę. Nowa rozpatrywana w pracy przyczyna nadmiernego zużycia kół zestawów kołowych dotyczy nieprawidłowej ich orientacji względem ramy wózka. Sytuację taką zdiagnozowano w wagonach towarowych posadowionych na wózkach z rodziny Y25, w wyniku niepoprawnego procesu naprawy ramy wózka i regeneracji maźnic. W pracy przedstawiono wyniki pomiarów przeprowadzonych na rzeczywistym wagonie towarowym oraz identyfikację zużyć i geometrii elementów pojazdu. W celu ilościowej analizy wpływu niepoprawnie zorientowanych osi zestawów kołowych na wielkość zużycia kół powstał model numeryczny, opisujący dynamikę ww. wagonu towarowego. Obliczenia numeryczne przeprowadzono przy różnych scenariuszach prędkości i geometrii toru oraz kilku wariantach zukosowania zestawów kołowych. Otrzymane z badań numerycznych wyniki wykazały istotny wpływ nierównoległości osi zestawów kołowych na nierównomierne zużycie profili kół. Zaprezentowana w pracy teza poparta wynikami badań może w znacznym stopniu wpłynąć na poprawę technologii wykonywania napraw układu biegowego oraz warunki utrzymania towarowego taboru kolejowego. Pozwoli także na redukując kosztów napraw zestawów kołowych i wydłużenie okresu ich eksploatacji.

Keywords:
zużycie kół, dynamiki pojazdów, badania numeryczne, transport towarowy

34.Bogacz R., Konowrocki R., Uszkodzenia pojazdów szynowych wywołane usterkami toru kolejowego , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.80-81, 2018
Bogacz R., Konowrocki R., Uszkodzenia pojazdów szynowych wywołane usterkami toru kolejowego , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.80-81, 2018

Abstract:
Praca zawiera omówienie wybranych zagadnień dynamicznych związanych
z kinematycznym wymuszeniem od usterek toru wpływającym na degradację elementów pojazdów szynowych oraz rozwój uszkodzeń infrastruktury. Wskazano zjawiska, które mogą być przyczyną dużych obciążeń współdziałającego ze sobą układu pojazd-tor oraz zagrożenia wypadkami spowodowanymi zmęczeniem materiału elementów takiego układu. Podano przyczyny powstawania i rozwoju pęknięć szyn i osi zestawów kołowych. Przedstawiono przykłady badań doświadczalnych wskazujących na występowanie obciążeń dynamicznych znacznie przekraczających obciążenia statyczne spowodowane oddziaływaniem pojazdu i jego układu napędowego. Omówiono i zamieszczono w pracy wyniki badań teoretycznych uzyskanych z numerycznego modelu napędu pociągu z uwzględnieniem elektromechanicznych sprzęgnięć pomiędzy silnikiem a zestawem kołowym. Model ten pozwolił na analizę niekorzystych drgań skrętnych zestawu kołowego towarzyszących podczas przejazdu przez szczeliny w pojedynczym toku szynowym toru.
Prezentowane w pracy wyniki odniesiono do badań eksperymentalnych. W pracy przedstawiono również zagadnienia dynamiczne związane z samowzbudnością wskazujące na zjawiska, które mogą być przyczyną dużych obciążeń osi zestawów kołowych, jak również toru i ich degradacji oraz uszkodzeń zmęczeniowych tych osi. Zasygnalizowane zostały prawdopodobne przyczyny powstawania wielokrotnie większych od powszechnie uznawanych obciążeń szyn kołami kolejowymi. Podano kilka przykładów eksperymentalnego zbadania dynamicznego oddziaływania zestawów kołowych z torem będącego alternatywnym podejściem do kinematycznego wyjaśniania tego zjawiska.

Keywords:
drgania skrętne, uszkodzenia pojazdu i toru, dynamiki toru, badania numeryczne

35.Konowrocki R., Dąbrowski A., Brona P., Application of longitudinal dynamics of the train in the simulator of catenary maintenance vehicles - experimental and numerical tests , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.19-20, 2018
Konowrocki R., Dąbrowski A., Brona P., Application of longitudinal dynamics of the train in the simulator of catenary maintenance vehicles - experimental and numerical tests , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.19-20, 2018

Abstract:
The paper presents results obtained from experimental and simulation tests of trains, treated as simplified one-dimensional models of railway vehicles. This approach to train dynamics enables to assess train forces and their impact on dynamic characteristics, for example related to some problems of rapid starting or emergency braking. These works were used to implement them as a solver mechanism in the simulator of catenary maintenance trains, whose features in the article are discussed. In the paper algorithm of operating vehicles by their drivers in different driving scenarios are presents. The algorithm described simulator must meet atypical requirements resulting from the specific properties of the simulated vehicles.The paper describes also the methodology of identifying driving system of modeled vehicles and the way of adaptation of parameters obtained experimentally. Then, in brief, issues related to the image animation and presentation in the simulator are discussed. Also the most important rules of operating rail vehicle simulator, selecting proper scenarios and using effective training methods are characterised. Results of operational and numerical tests presented in the paper reflect in details processes accompanying the operation of catenary maintenance trains. The experimental test methodology to the real railway vehicles to acquire some missing work parameters was allowed. Results of the presented research indicate a large convergence of theoretical results with the experiment.The obtained result allowed to validate the work of the simulator

Keywords:
training simulator, dynamics of the train, experimental test, VBS3 environmental

36.Konowrocki R., Modeling of dynamic aspects of operation railway vehicle traction drive system including the electromechanical coupling , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.46-47, 2018
Konowrocki R., Modeling of dynamic aspects of operation railway vehicle traction drive system including the electromechanical coupling , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.46-47, 2018

Abstract:
In the paper, a dynamic electromechanical interaction between the wheelset of railway vehicle and its driving electric motors is investigated. This is the high-speed train driven by the electric motors through elastic hollow shaft with linear characteristics. In particular, there is considered an influence of negative electromagnetic damping generated by the motor on a possibility of excitation of resonant torsional vibrations. Conclusions drawn from the computational results can be very useful during a design phase of these devices as well as helpful for their users during a regular maintenance.

Keywords:
electromechanical coupling, torsion oscilation, electric motor, high speed train drive

37.Konowrocki R., Groll W., Kukulski J., Walczak S., Badania doświadczalne i symulacyjne powstawania gorących obszarów w parach ciernych hamulca kolejowego pociągów dużych prędkości , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.20-21, 2018
Konowrocki R., Groll W., Kukulski J., Walczak S., Badania doświadczalne i symulacyjne powstawania gorących obszarów w parach ciernych hamulca kolejowego pociągów dużych prędkości , XXIII Scientific Conference Railway Vehicles 2018, 2018-05-22/05-25, Szczyrk (PL), pp.20-21, 2018

Abstract:
Pracę poświęcono eksperymentalnym i numerycznym badaniom dotyczącym występowania gorących punktów w elementach hamulców tarczowych stosowanego w pojazdach szynowych dużej prędkości. W pracy zaprezentowano wyniki eksperymentalnych badań przeprowadzone na rzeczywistym układzie hamulcowym dedykowanym do takich pojazdów. W badaniach eksperymentalnych wykorzystano technikę termografii w podczerwieni, która pozwoliła scharakteryzować omawiane zjawiska cieplne. Uzyskane wyniki badań doświadczanych potwierdzono analizami numerycznymi, przy wykorzystaniu z walidowanego modelu układu hamulcowego. Wykorzystano w tym celu metodę elementów skończonych. Otrzymane wyniki numeryczne ilustrują zjawisko powstawania gorących obszarów na powierzchni tarczy hamulcowej wywołane przez termoelastyczne zaburzenia występujące na jej powierzchni.

Keywords:
gorące obszary, badania numeryczne, badania eksperymentalne, układ hamulcowy, pociągi dużych prędkości

38.Jóźwiak-Niedźwiedzka D., Dąbrowski M., Gibas K., Antolik A., Glinicki M.A., Alkali-silica reaction and microstructure of concrete subjected to combined chemical and physical exposure conditions, MATBUD'2018, 8th Scientific-Technical Conference on Material Problems in Civil Engineering MATBUD'2018, 2018-06-25/06-27, Kraków, Politechnika Krakowska (PL), DOI: 10.1051/matecconf/201816305009, No.163, pp.05009-1-05009-10, 2018
Jóźwiak-Niedźwiedzka D., Dąbrowski M., Gibas K., Antolik A., Glinicki M.A., Alkali-silica reaction and microstructure of concrete subjected to combined chemical and physical exposure conditions, MATBUD'2018, 8th Scientific-Technical Conference on Material Problems in Civil Engineering MATBUD'2018, 2018-06-25/06-27, Kraków, Politechnika Krakowska (PL), DOI: 10.1051/matecconf/201816305009, No.163, pp.05009-1-05009-10, 2018

Abstract:
Salt solutions are used to ensure safe driving conditions during winter. NaCl deicer is the most often used brine in Polish climatic zone. The chemical effects of this type of chloride-based deicer in wetting and drying (WD) and temperature cycles on concrete need to be better understood. This research was focus to study the microstructure of air-entrained pavement concrete after combined chemical (10% of NaCl) and physical (WD and 60°C) exposure conditions. The adopted WD and temperature regime was designed to verify the hypothesis that regularly alternating wetting and drying cycles with external alkali supply from deicer salt will provoke the Alkali-Silica Reaction (ASR). The aggregates varied their origin and mineralogical composition. The microscopic examination was carried out on concrete specimens using SEM with EDX. The microscopic analysis has shown that main reason for concrete deterioration during cyclic chemical and physical exposure conditions was both physical influence - WD cycles and the chemical influence – ASR (primarily, the fine aggregate which lead to form of alkali-silica gel). The expansive gel was shown to be capable of destroying the test specimens. Also differences in mineralogical composition of coarse aggregates influenced on the concrete prism expansion due to ASR.

39.Antolik A., Glinicki M.A., Gawlicki M., Effect of boron-containing aggregates on setting and hardening of Portland cement mortars, MATBUD'2018, 8th Scientific-Technical Conference on Material Problems in Civil Engineering MATBUD'2018, 2018-06-25/06-27, Kraków, Politechnika Krakowska (PL), DOI: 10.1051/matecconf/201816304003, No.163, pp.04003-1-04003-6, 2018
Antolik A., Glinicki M.A., Gawlicki M., Effect of boron-containing aggregates on setting and hardening of Portland cement mortars, MATBUD'2018, 8th Scientific-Technical Conference on Material Problems in Civil Engineering MATBUD'2018, 2018-06-25/06-27, Kraków, Politechnika Krakowska (PL), DOI: 10.1051/matecconf/201816304003, No.163, pp.04003-1-04003-6, 2018

Abstract:
Multicomponent cement-based composites are known as versatile structural materials for enhanced radiation shielding. The use of selected elements, like boron, cadmium, or rare earth elements, provides an increased neutron shielding capacity. Because of profusion, reasonable costs and large cross-section for neutron capture, boron containing minerals are suggested as aggregates for radiation shielding concrete. Despite many advantages, boron additives may act as cement setting retarders. Uncontrolled setting and hardening is not acceptable in radiation shielding concrete technology. In this work we present results from isothermal calorimetry measurements on cement mortars with boron-containing aggregates. Four types of boron aggregates were used in the studies: colemanite, ulexite, borax and boron carbide. Based on calorimetric curves, the beginning of setting time was determined. Additionally early mortar strength was investigated and linear relationship between the heat generated in the isothermal calorimeter and the early compressive strength has been observed. The use of isothermal calorimetry allowed us to estimate the limits for the content of boron compounds to be used cement mortar.

40.Niemczyk B., Sajkiewicz P., Gradys A., The Effect of Chemical Composition on Crosslinking Kinetics of Methylcellulose/Agarose Hydrogel, ISBPPB 2018, 4th International Conference on Biomedical Polymers and Polymeric Biomaterials, 2018-07-15/07-18, Kraków (PL), pp.174, 2018
41.Pisarski D., On optimal distributed semi-active control of vibrating structures, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-23/07-26, Qingdao (CN), pp.3148-3149, 2018
Pisarski D., On optimal distributed semi-active control of vibrating structures, WCSCM, 7th World Conference on Structural Control and Monitoring, 2018-07-23/07-26, Qingdao (CN), pp.3148-3149, 2018

Abstract:
A novel semi-active control method for mitigation of structural vibration is studied. The
method relies on distributed state information patterns and solutions to optimal control
problem that aims at replicating the structures of the optimal open-loop switched stabilizing
controls. The performance of the designed method is validated by means of numerical
experiments performed for a double cantilever system equipped with a set of semi-active
elastomers with controlled viscoelastic properties.

42.Czarny P., Kwiatkowski D., Toma M., Kubiak J., Sliwinska A., Talarowska M., Szemraj J., Maes M., Galecki P., Sliwinski T., Impact of single-nucleotide polymorphisms of base excision repair genes on DNA damage and efficiency of DNA repair in recurrent depression disorder, MOLECULAR NEUROBIOLOGY, ISSN: 0893-7648, DOI: 10.1007/s12035-016-9971-6, Vol.54, No.6, pp.4150-4159, 2017
Czarny P., Kwiatkowski D., Toma M., Kubiak J., Sliwinska A., Talarowska M., Szemraj J., Maes M., Galecki P., Sliwinski T., Impact of single-nucleotide polymorphisms of base excision repair genes on DNA damage and efficiency of DNA repair in recurrent depression disorder, MOLECULAR NEUROBIOLOGY, ISSN: 0893-7648, DOI: 10.1007/s12035-016-9971-6, Vol.54, No.6, pp.4150-4159, 2017

Abstract:
Elevated level of DNA damage was observed in patients with depression. Furthermore, single nucleotide polymorphisms (SNPs) of base excision repair (BER) genes may modulate the risk of this disease. Therefore, the aim of this study was to delineate the association between DNA damage, DNA repair, the presence of polymorphic variants of BER genes, and occurrence of depression. The study was conducted on peripheral blood mononuclear cells of 43 patients diagnosed with depression and 59 controls without mental disorders. Comet assay was used to assess endogenous (oxidative) DNA damage and efficiency of DNA damage repair (DRE). TaqMan probes were employed to genotype 12 SNPs of BER genes. Endogenous DNA damage was higher in the patients than in the controls, but none of the SNPs affected its levels. DRE was significantly higher in the controls and was modulated by BER SNPs, particularly by c.977C > G-hOGG1, c.972G > C-MUTYH, c.2285T > C-PARP1, c.580C > T-XRCC1, c.1196A > G-XRCC1, c.444T > G-APEX1, c.-468T > G-APEX1, or c.*50C > T-LIG3. Our study suggests that both oxidative stress and disorders in DNA damage repair mechanisms contribute to elevated levels of DNA lesions observed in depression. Lower DRE can be partly attributed to the presence of specific SNP variants.

Keywords:
Recurrent depression disorder, DNA damage, DNA repair, Oxidative stress, Base excision repair, Single nucleotide polymorphism

43.Sliwinska A., Sitarek P., Toma M., Czarny P., Synowiec E., Krupa R., Wigner P., Bialek K., Kwiatkowski D., Korycinska A., Majsterek I., Szemraj J., Galecki P., Sliwinski T., Decreased expression level of BER genes in Alzheimer’s disease patients is not derivative of their DNA methylation status, PROGRESS IN NEURO-PSYCHOPHARMACOLOGY & BIOLOGICAL PSYCHIATRY, ISSN: 0278-5846, DOI: 10.1016/j.pnpbp.2017.07.010, Vol.79, pp.311-316, 2017
Sliwinska A., Sitarek P., Toma M., Czarny P., Synowiec E., Krupa R., Wigner P., Bialek K., Kwiatkowski D., Korycinska A., Majsterek I., Szemraj J., Galecki P., Sliwinski T., Decreased expression level of BER genes in Alzheimer’s disease patients is not derivative of their DNA methylation status, PROGRESS IN NEURO-PSYCHOPHARMACOLOGY & BIOLOGICAL PSYCHIATRY, ISSN: 0278-5846, DOI: 10.1016/j.pnpbp.2017.07.010, Vol.79, pp.311-316, 2017

Abstract:
Background: Neurodegeneration in Alzheimer's disease can be caused by accumulation of oxidative DNA damage resulting from altered expression of genes involved in the base excision repair system (BER). Promoter methylation can affect the profile of BER genes expression. Decreased expression of BER genes was observed in the brains of AD patients.

Aim of the study: The aim of our study was to compare the expression and methylation profiles of six genes coding for proteins involved in BER, namely: hOGG1, APE1, MUTYH, NEIL1, PARP1 and XRCC1, in the peripheral blood cells of AD patients and healthy volunteers.

Methods: The study consisted of 100 persons diagnosed with Alzheimer's disease according to DSM-IV criteria, and 110 healthy volunteers. DNA and total RNA were isolated from venous blood cells. Promoter methylation profiles were obtained by High Resolution Melting (HRM) analysis of bisulfide converted DNA samples. Real-time PCR with TaqMan probes was employed for gene expression analysis.

Results: APE1, hOGG1, MUTYH, PARP1 and NEIL1 were significantly (p < 0.001) down-regulated in the lymphocytes of AD patients, as compared to healthy volunteers. Expression of XRCC1 didn't differ significantly between both groups. We did not find any differences in the methylation pattern of any of the investigated BER genes.

Conclusions: The methylation status of promoters is not associated with downregulation of BER genes. Our results show that downregulation of BER genes detected in peripheral blood samples could reflect the changes occurring in the brain of patients with AD, and may be a useful biomarker of this disease.

Keywords:
Alzheimer's disease, DNA base excision repair genes, Gene expression, Promoter methylation

44.Niemczyk B., Sajkiewicz P., The effect of chemical composition on viscoelastic properties of methylcellulose/agarose hydrogel, 7th KMM-VIN Industrial Workshop “Biomaterials: Key Technologies for Better Healthcare”, 2017-09-27/09-28, Erlangen (DE), pp.44, 2017
Niemczyk B., Sajkiewicz P., The effect of chemical composition on viscoelastic properties of methylcellulose/agarose hydrogel, 7th KMM-VIN Industrial Workshop “Biomaterials: Key Technologies for Better Healthcare”, 2017-09-27/09-28, Erlangen (DE), pp.44, 2017

Keywords:
methylcellulose, agarose, hydrogel, cross-linking kinetics, DMA, modulus

45.Kwiatkowski D., Czarny P., Toma M., Jurkowska N., Śliwinska A., Drzewoski J., Bachurska A., Szemraj J., Maes M., Berk M., Su K.P., Gałecki P., Śliwiński T., Associations between DNA Damage, DNA Base Excision Repair Gene Variability and Alzheimer's Disease Risk, DEMENTIA AND GERIATRIC COGNITIVE DISORDERS, ISSN: 1420-8008, DOI: 10.1159/000443953, Vol.41, No.3-4, pp.152-171, 2016
Kwiatkowski D., Czarny P., Toma M., Jurkowska N., Śliwinska A., Drzewoski J., Bachurska A., Szemraj J., Maes M., Berk M., Su K.P., Gałecki P., Śliwiński T., Associations between DNA Damage, DNA Base Excision Repair Gene Variability and Alzheimer's Disease Risk, DEMENTIA AND GERIATRIC COGNITIVE DISORDERS, ISSN: 1420-8008, DOI: 10.1159/000443953, Vol.41, No.3-4, pp.152-171, 2016

Abstract:
Background: Increased oxidative damage to DNA is one of the pathways involved in Alzheimer's disease (AD). Insufficient base excision repair (BER) is in part responsible for increased oxidative DNA damage. The aim of the present study was to assess the effect of polymorphic variants of BER-involved genes and the peripheral markers of DNA damage and repair in patients with AD. Material and Methods: Comet assays and TaqMan probes were used to assess DNA damage, BER efficiency and polymorphic variants of 12 BER genes in blood samples from 105 AD patients and 130 controls. The DNA repair efficacy (DRE) was calculated according to a specific equation. Results: The levels of endogenous and oxidative DNA damages were higher in AD patients than controls. The polymorphic variants of XRCC1 c.580C>T XRCC1 c.1196A>G and OGG1 c.977C>G are associated with increased DNA damage in AD. Conclusion: Our results show that oxidative stress and disturbances in DRE are particularly responsible for the elevated DNA lesions in AD. The results suggest that oxidative stress and disruption in DNA repair may contribute to increased DNA damage in AD patients and risk of this disease. In addition, disturbances in DRE may be associated with polymorphisms of OGG1 and XRCC1.

Keywords:
DNA damage, DNA base excision repair, Alzheimer's disease risk, Dementia, Oxidative stress

46.Sliwinska A., Kwiatkowski D., Czarny P., Toma M., Wigner P., Drzewoski J., Fabianowska-Majewska K., Szemraj J., Maes M., Gałecki P., Śliwiński T., The levels of 7,8-dihydrodeoxyguanosine (8-oxoG) and 8-oxoguanine DNA glycosylase 1 (OGG1) - A potential diagnostic biomarkers of Alzheimer's disease, JOURNAL OF THE NEUROLOGICAL SCIENCES, ISSN: 0022-510X, DOI: 10.1016/j.jns.2016.07.008, Vol.368, pp.155-159, 2016
Sliwinska A., Kwiatkowski D., Czarny P., Toma M., Wigner P., Drzewoski J., Fabianowska-Majewska K., Szemraj J., Maes M., Gałecki P., Śliwiński T., The levels of 7,8-dihydrodeoxyguanosine (8-oxoG) and 8-oxoguanine DNA glycosylase 1 (OGG1) - A potential diagnostic biomarkers of Alzheimer's disease, JOURNAL OF THE NEUROLOGICAL SCIENCES, ISSN: 0022-510X, DOI: 10.1016/j.jns.2016.07.008, Vol.368, pp.155-159, 2016

Abstract:
Evidence indicates that oxidative stress contributes to neuronal cell death in Alzheimer's disease (AD). Increased oxidative DNA damage I, as measured with 8-oxoguanine (8-oxoG), and reduced capacity of proteins responsible for removing of DNA damage, including 8-oxoguanine DNA glycosylase 1 (OGG1), were detected in brains of AD patients. In the present study we assessed peripheral blood biomarkers of oxidative DNA damage, i.e. 8-oxoG and OGG1, in AD diagnosis, by comparing their levels between the patients and the controls. Our study was performed on DNA and serum isolated from peripheral blood taken from 100 AD patients and 110 controls. For 8-oxoG ELISA was employed. The OGG1 level was determined using ELISA and Western blot technique. Levels of 8-oxoG were significantly higher in DNA of AD patients. Both ELISA and Western blot showed decreased levels of OGG1 in serum of AD patients. Our results show that oxidative DNA damage biomarkers detected in peripheral tissue could reflect the changes occurring in the brain of patients with AD. These results also suggest that peripheral blood samples may be useful to measure oxidative stress biomarkers in AD.

Keywords:
Alzheimer's disease, Oxidative stress, Oxidative DNA damage, 7 8-dihydrodeoxyguanosine (8-oxoG), DNA base excision repair, 8-oxoguanine DNA glycosylase 1 (OGG1)

47.Kwiatkowski D., Czarny P., Toma M., Korycinska A., Sowinska K., Gałecki P., Bachurska A., Bielecka-Kowalska A., Szemraj J., Maes M., Śliwiński T., Association between single nucleotide polymorphisms of hOGG1, NEIL1, APEX1, FEN1, LIG1 and LIG3 genes and Alzheimer’s disease risk, NEUROPSYCHOBIOLOGY, ISSN: 0302-282X, DOI: 10.1159/000444643, Vol.73, No.2, pp.98-107, 2016
Kwiatkowski D., Czarny P., Toma M., Korycinska A., Sowinska K., Gałecki P., Bachurska A., Bielecka-Kowalska A., Szemraj J., Maes M., Śliwiński T., Association between single nucleotide polymorphisms of hOGG1, NEIL1, APEX1, FEN1, LIG1 and LIG3 genes and Alzheimer’s disease risk, NEUROPSYCHOBIOLOGY, ISSN: 0302-282X, DOI: 10.1159/000444643, Vol.73, No.2, pp.98-107, 2016

Abstract:
Background: One of the factors that contribute to Alzheimer's disease (AD) is the DNA damage caused by oxidative stress and inflammation that occurs in nerve cells. It has been suggested that the risk of AD may be associated with an age dependent reduction of the DNA repair efficiency. Base excision repair (BER) is, among other things, a main repair system of oxidative DNA damage. One of the reasons for the reduced efficiency of this system may be single-nucleotide polymorphisms (SNP) of the genes encoding its proteins. Methods: DNA for genotyping was obtained from the peripheral blood of 281 patients and 150 controls. In the present study, we evaluated the impact of 8 polymorphisms of 6 BER genes on the AD risk. We analyzed the following SNP: c.-468T>G and c.444T>G of APEX1, c.*50C>T and c.*83A>C of LIG3, c.977C>G of OGG1, c.*283C>G of NEIL1, c.-441G>A of FEN1, and c.-7C>T of LIG1. Results: We showed that the LIG1 c.-7C>T A/A and LIG3 c.*83A>C A/C variants increased, while the APEX1 c.444T>G G/T, LIG1 c.-7C>T G/, LIG3 c.*83A>C C/C variants reduced, the AD risk. We also evaluated the relation between gene-gene interactions and the AD risk. We showed that combinations of certain BER gene variants such as c.977C>Gxc.*50C>T CC/CT, c./111T>Gxc.*50C>T GG/CT, c.-468T>Gxc.*50C>T GG/CT, c.-441G>Ac.*50C>Txc.*50C>T GG/CT, c.*83A>Cx c.*50C>T CT/AC, and c.-7C>Txc.*50C>T CT/GG can substantially positively modulate the risk of AD. Conclusions: In conclusion, we revealed that polymorphisms of BER genes may have a significant effect on the AD risk, and the presence of polymorphic variants may be an important marker for AD.

Keywords:
Alzheimer's disease, Base excision repair, Polymorphisms

48.Czarny P., Kwiatkowski D., Toma M., Gałecki P., Orzechowska A., Bobińska K., Bielecka-Kowalska A., Szemraj J., Berk M., Anderson G., Śliwiński T., Single-nucleotide polymorphisms of genes involved in repair of oxidative DNA damage and the risk of recurrent depressive disorder, Medical Science Monitor, ISSN: 1643-3750, DOI: 10.12659/MSM.898091, Vol.22, pp.4455-4474, 2016
Czarny P., Kwiatkowski D., Toma M., Gałecki P., Orzechowska A., Bobińska K., Bielecka-Kowalska A., Szemraj J., Berk M., Anderson G., Śliwiński T., Single-nucleotide polymorphisms of genes involved in repair of oxidative DNA damage and the risk of recurrent depressive disorder, Medical Science Monitor, ISSN: 1643-3750, DOI: 10.12659/MSM.898091, Vol.22, pp.4455-4474, 2016

Abstract:
Background: Depressive disorder, including recurrent type (rDD), is accompanied by increased oxidative stress and activation of inflammatory pathways, which may induce DNA damage. This thesis is supported by the presence of increased levels of DNA damage in depressed patients. Such DNA damage is repaired by the base excision repair (BER) pathway. BER efficiency may be influenced by polymorphisms in BER-related genes. Therefore, we genotyped nine single-nucleotide polymorphisms (SNPs) in six genes encoding BER proteins.

Material/Methods: Using TaqMan, we selected and genotyped the following SNPs: c.-441G>A (rs174538) of FEN1, c.2285T>C (rs1136410) of PARP1, c.580C>T (rs1799782) and c.1196A>G (rs25487) of XRCC1, c.*83A>C (rs4796030) and c.*50C>T (rs1052536) of LIG3, c.-7C>T (rs20579) of LIG1, and c.-468T>G (rs1760944) and c.444T>G (rs1130409) of APEX1 in 599 samples (288 rDD patients and 311 controls).

Results: We found a strong correlation between rDD and both SNPs of LIG3, their haplotypes, as well as a weaker association with the c.-468T>G of APEXI which diminished after Nyholt correction. Polymorphisms of LIG3 were also associated with early onset versus late onset depression, whereas the c.-468T>G polymorphism showed the opposite association.

Conclusions: The SNPs of genes involved in the repair of oxidative DNA damage may modulate rDD risk. Since this is an exploratory study, the results should to be treated with caution and further work needs to be done to elucidate the exact involvement of DNA damage and repair mechanisms in the development of this disease.

Keywords:
Depression, DNA Repair, Inflammation, Oxidative Stress, Polymorphism, Single Nucleotide

49.Bocheński M., Augustyniak M., Ostrowski M., Jarzyna W., The influence of control algorithms on the effectiveness of vibration reduction of an active composite beam, PRZEGLĄD ELEKTROTECHNICZNY, ISSN: 0033-2097, DOI: 10.15199/48.2016.08.45, No.8, pp.166-169, 2016
Bocheński M., Augustyniak M., Ostrowski M., Jarzyna W., The influence of control algorithms on the effectiveness of vibration reduction of an active composite beam, PRZEGLĄD ELEKTROTECHNICZNY, ISSN: 0033-2097, DOI: 10.15199/48.2016.08.45, No.8, pp.166-169, 2016

Abstract:
The paper presents application of the MFC actuator and selected control algorithms to the suppression of the composite cantilever beam vibrations. The first part concentrates on the identification of the real structure’s parameters. The numerical model is based on the Euler-Bernoulli beam theory with a nonlinear curvature component. The second part draws on numerical simulations and leads to the identification of optimal control parameters. Finally, the determined parameters are examined in an experimental laboratory system equipped with a DSP controller.

Keywords:
MFC actuator, control algorithm, active beam, DSP controller

50.Ostrowski M., Jarzyna W., REDUKCJA DRGAŃ OBIEKTU NIELINIOWEGO Z REGULATOREM ADAPTACYJNYM PROPORCJONALNO-RÓŻNICZKUJĄCYM O STRUKTURZE MRAS, IAPGOŚ, ISSN: 2083-0157, DOI: 10.5604/20830157.1194278, Vol.6, No.1, pp.51-54, 2016
Ostrowski M., Jarzyna W., REDUKCJA DRGAŃ OBIEKTU NIELINIOWEGO Z REGULATOREM ADAPTACYJNYM PROPORCJONALNO-RÓŻNICZKUJĄCYM O STRUKTURZE MRAS, IAPGOŚ, ISSN: 2083-0157, DOI: 10.5604/20830157.1194278, Vol.6, No.1, pp.51-54, 2016

Abstract:
W artykule zaprezentowano metodę adaptacji algorytmu sterowania aktuatorem MFC służącym do redukcji drgań nieliniowych belki wysięgnikowej. Zastosowany opis matematyczny regulatora PD zaprojektowano jako strukturę MRAS, a algorytm adaptacji oparty jest o zasadę Lapunowa. Przeprowadzone badania symulacyjne określiły odporność algorytmu na błędy modelowania oraz na występujące w rzeczywistych systemach opóźnienia sprzętowe.

Keywords:
regulacja adaptacyjna, algorytm adaptacji Lapunowa, drgania belki wysięgnikowej, aktuator MFC

51.Kosny J., Curcija Ch., Fontanini A., Kossecka E., A New Approach for Analysis of Complex Building Envelopes in Whole Building Energy Simulations, Buildings XIII - Thermal Performance of the Exterior Envelope of Whole Buildings Conference, 2016-09-04/09-08, Clearwater Beach, FL (US), pp.1-26, 2016
Kosny J., Curcija Ch., Fontanini A., Kossecka E., A New Approach for Analysis of Complex Building Envelopes in Whole Building Energy Simulations, Buildings XIII - Thermal Performance of the Exterior Envelope of Whole Buildings Conference, 2016-09-04/09-08, Clearwater Beach, FL (US), pp.1-26, 2016

Abstract:
The ability for reduction of whole-building energy consumption depends, in large scales, from correct predictions of building thermal loads with the building’s envelope characteristics being one of the most important factors. Since most of today’s building envelopes are complex three-dimensional networks of structural, insulation, and finish materials, the potential for correct predictions of their thermal performance depends on availability of acceptable, scientifically valid, consensus procedures for accurately implementing a building’s envelope thermal characteristics into whole-building energy simulation programs.
This paper is discusses a joint LBNL and Fraunhofer CSE project, focused on the upgrade of the already existing THERM program and its integration with EnergyPlus, a whole-building energy simulation tool. It is expected that these two programs, combined together, will eliminate typical analytical limitations of most of existing whole building energy tools, capable to simulate only simplified one-dimensional envelopes. The main research challenge is the design of an easy to implement upgrade of the THERM numerical tool to allow analysis of complex building envelope structures. The new version of THERM needs to be able to modify thermal characteristics of the complex three-dimensional (3-D) wall assemblies, in a way to enable their use in whole building energy simulation programs. It will be achieved through an application of the unique theoretical procedure, which will allow a generation of the simplified one-dimensional (1-D) wall geometry and material characteristics to fully and accuratly capture the dynamic effects of thermal bridges.
At this stage of the project, the research team focuses on development of theoretical bases for necessary changes in the THERM framework. This paper explains the theoretical methodology which is used and presents some results from the series of steady-state and dynamic heat transfer simulations performed on building envelopes architectural components, to illustrate the accuracy limitations associated with thermal calculation methods recommended by building energy codes worldwide.

52.Mikułowski G., Fournier M., Porchez T., Belly C., Claeyssen F., Semi-Passive Vibration Control Technique via Shunting of Amplified Piezoelectric Actuators, ACTUATOR 2016, 15th International Conference on New Actuators, 2016-06-13/06-15, Bremen (DE), pp.542-546, 2016
Mikułowski G., Fournier M., Porchez T., Belly C., Claeyssen F., Semi-Passive Vibration Control Technique via Shunting of Amplified Piezoelectric Actuators, ACTUATOR 2016, 15th International Conference on New Actuators, 2016-06-13/06-15, Bremen (DE), pp.542-546, 2016

Abstract:
The objective of this paper is to provide results of an experimental and analytical investigation of Amplified Piezoelectric Actuators (APA) as vibrational isolator in a configuration of a mechanical Single Degree of Freedom system. The investigation is aimed at assessment of the mechanical properties modification ability via shunting techniques. The investigation consist of a phenomenological modelling of the APAs considered as generators and experimental verification of the vibrational energy dissipation ability in frequency domain. The results obtained during this investigation reveal that it is feasible to receive more than 20 dB reduction of the displacement amplification in the resonant range. Moreover, three tested examples of APA reveal up to 9 % of resonant frequency shift due to proper adjustment of the electronic shunting circuit, which is an encouragement for further analyses towards application of the APAs in semi-passive vibration control applications.

Keywords:
Vibration, Dissipation, Adaptive, Piezoelectric

53.Czarny P., Kwiatkowski D., Gałecki P., Talarowska M., Orzechowska A., Bobińska K., Bielecka-Kowalska A., Szemraj J., Maes M., Su K.P., Śliwiński T., Association between single nucleotide polymorphisms of MUTYH, hOGG1 and NEIL1 genes, and depression, JOURNAL OF AFFECTIVE DISORDERS, ISSN: 0165-0327, DOI: 10.1016/j.jad.2015.05.044, Vol.184, pp.90-96, 2015
Czarny P., Kwiatkowski D., Gałecki P., Talarowska M., Orzechowska A., Bobińska K., Bielecka-Kowalska A., Szemraj J., Maes M., Su K.P., Śliwiński T., Association between single nucleotide polymorphisms of MUTYH, hOGG1 and NEIL1 genes, and depression, JOURNAL OF AFFECTIVE DISORDERS, ISSN: 0165-0327, DOI: 10.1016/j.jad.2015.05.044, Vol.184, pp.90-96, 2015

Abstract:
Background: An elevated levels oxidative modified DNA bases and a decreased efficiency of oxidative DNA damage repair were found in patients with depression disorders, including recurrent type (rDD). The glycosylases are involved in base excision repair (BER), which eliminates oxidative DNA damage. Therefore, we genotyped the single nucleotide polymorphisms (SNPs) of genes encoding three glycosylases: hOGG1, MUTYH and NEILL

Methods: We selected three polymorphisms: c.977C > G - hOGG1 (rs1052133), c.972G > C - MUTYH (rs3219489) and c.*589G > C - NEIL1 (rs4462560). A total of 555 DNA samples (257 cases and 298 controls) were genotyped using TaqMan probes.

Results: The C/C genotype and allele C of the c.*589G > C decreased the risk of rDD occurrence, while the G/G genotype and allele G of the same SNP increased the risk. This polymorphism had a stronger association with early-onset depression (patients with first episode <35 years of age) than with late onset depression (first episode >= 35 years of age). We did not find any significant differences in distribution of alleles and genotypes of other SNPs; however, the G/G genotype of the c.972G > C increased the risk of late onset rDD. We also found that combined genotype C/C-C/C of c.977C > G and c.*589G > C significantly reduced the risk of rDD.

Limitations: Limited sample size and ethnic homogeneity of the studied population.

Conclusion: This is the first study to show that SNPs of genes involved in DNA repair, particularly in BER pathway, may modulate the risk of rDD. These results further support the hypothesis on the involvement of DNA repair mechanisms in pathogenesis of depression.

Keywords:
Depression, Glycosylases, BER, DNA repair, DNA damage

54.Kwiatkowski D., Czarny P., Gałecki P., Bachurska A., Talarowska M., Orzechowska A., Bobińska K., Bielecka-Kowalska A., Pietras T., Szemraj J., Maes M., Śliwiński T., Variants of Base Excision Repair Genes MUTYH, PARP1 and XRCC1 in Alzheimer's Disease Risk, NEUROPSYCHOBIOLOGY, ISSN: 0302-282X, DOI: 10.1159/000381985, Vol.71, No.3, pp.176-186, 2015
Kwiatkowski D., Czarny P., Gałecki P., Bachurska A., Talarowska M., Orzechowska A., Bobińska K., Bielecka-Kowalska A., Pietras T., Szemraj J., Maes M., Śliwiński T., Variants of Base Excision Repair Genes MUTYH, PARP1 and XRCC1 in Alzheimer's Disease Risk, NEUROPSYCHOBIOLOGY, ISSN: 0302-282X, DOI: 10.1159/000381985, Vol.71, No.3, pp.176-186, 2015

Abstract:
Background: Many clinical studies have shown that oxidative stress pathways and the efficiency of the oxidative DNA damage base excision repair (BER) system are associated with the pathogenesis of Alzheimer's disease (AD). Reduced BER efficiency may result from polymorphisms of BER-related genes. In the present study, we examine whether single nucleotide polymorphisms (SNPs) of BER genes are associated with increased risk of AD. Methods: SNP genotyping was carried out on DNA isolated from peripheral blood mononuclear cells obtained from 120 patients with AD and 110 healthy volunteers. Samples were genotyped for the presence of BER-related SNPs, i.e.XRCC1-rs1799782, rs25487; MUTYH-rs3219489, and PARP1-rs1136410. Results: We found a positive association between AD risk and the presence of G/A genotype variant of the XRCC1 rs25487 polymorphism [odds ratio (OR) = 3.762,95% Cl: 1.793-7.8911. The presence of the A/A genotype of this polymorphism reduced the risk of AD (OR = 0.485,95% Cl: 0.271-0.870). In cases of the PARP1 gene rs1136410 polymorphism, we observed that the T/C variant increases (OR =4.159, 95% Cl: 1.978-8.745) while the T/T variant reduces risk (OR = 0.240,95% Cl: 0.114-0.556) of AD. Conclusions: We conclude that BER gene polymorphisms may play an important role in the etiology of AD. Diagnosing the presence or absence of particular genetic variants may be an important marker of AD. Further research on a larger population is needed. There is also a need to examine polymorphisms of other BER in the context of AD risk.

Keywords:
Alzheimer's disease, Base excision repair, Polymorphisms

55.Śliwińska A., Kwiatkowski D., Czarny P., Milczarek J., Toma M., Korycinska A., Szemraj J., Śliwiński T., Genotoxicity and cytotoxicity of ZnO and Al2O3 nanoparticles, TOXICOLOGY MECHANISMS AND METHODS, ISSN: 1537-6516, DOI: 10.3109/15376516.2015.1006509, Vol.25, No.3, pp.176-183, 2015
Śliwińska A., Kwiatkowski D., Czarny P., Milczarek J., Toma M., Korycinska A., Szemraj J., Śliwiński T., Genotoxicity and cytotoxicity of ZnO and Al2O3 nanoparticles, TOXICOLOGY MECHANISMS AND METHODS, ISSN: 1537-6516, DOI: 10.3109/15376516.2015.1006509, Vol.25, No.3, pp.176-183, 2015

Abstract:
Objectives: Metal oxide nanoparticles (ZnO-NPs and Al2O3-NPs) are used in many fields, including consumer products and biomedical applications. As a result, exposure to these NPs is highly frequent, however, no conclusive information on their potential cytotoxicity and genotoxicity mechanisms are available. For this reason, we studied cytotoxic and genotoxic effects of ZnO-NPs and Al2O3-NPs on human peripheral blood lymphocytes.

Materials and methods: We obtained our goals by using MTT assay, Annexin V-FITC flow cytometry, and alkaline, neural and pH 12.1 versions of comet assay.

Results: Exposure of lymphocytes to both NPs for 24 h slightly decreased viability of lymphocytes at >= 0.5 mM. For the first time, we revealed using the comet assays that both ZnO-NPs and Al2O3-NPs caused a concentration-dependent increase of DNA single-strand breaks, but not alkali-labile sites. Treatment with DNA glycosylases showed that the NPs induced oxidative DNA damage. DNA damage caused by both nanoparticles at 0.05 mM was removed within 120 min, however lymphocytes did not repair DNA damage induced by 0.5 mM NPs. Studied nanoparticles did not induce apoptosis in lymphocytes.

Conclusion: Our results suggest that ZnO-NPs and Al2O3-NPs at concentration up to 0.5 mM did not exhibit cytotoxic effect but may exert genotoxic effect on lymphocytes, at least partially by the generation of oxidative DNA damage and strand breaks.

Keywords:
DNA repair, oxidative DNA damage, single and double strand breaks

56.Czarny P., Kwiatkowski D., Kacperska D., Kawczyńska D., Talarowska M., Orzechowska A., Bielecka-Kowalska A., Szemraj J., Gałecki P., Śliwiński T., Elevated Level of DNA Damage and Impaired Repair of Oxidative DNA Damage in Patients with Recurrent Depressive Disorder, Medical Science Monitor, ISSN: 1643-3750, DOI: 10.12659/MSM.892317, Vol.21, pp.412-418, 2015
Czarny P., Kwiatkowski D., Kacperska D., Kawczyńska D., Talarowska M., Orzechowska A., Bielecka-Kowalska A., Szemraj J., Gałecki P., Śliwiński T., Elevated Level of DNA Damage and Impaired Repair of Oxidative DNA Damage in Patients with Recurrent Depressive Disorder, Medical Science Monitor, ISSN: 1643-3750, DOI: 10.12659/MSM.892317, Vol.21, pp.412-418, 2015

Abstract:
Background: Depressive disorder (DD), including recurrent DD (rDD), is a severe psychological disease, which affects a large percentage of the world population. Although pathogenesis of the disease is not known, a growing body of evidence shows that inflammation together with oxidative stress may contribute to development of DD. Since reactive oxygen species produced during stress may damage DNA, we wanted to evaluate the extent of DNA damage and efficiency of DNA repair in patients with depression.

Material/Methods: We measured and compared the extent of endogenous DNA damage - single- and double-strand breaks, alkali-labile sites, and oxidative damage of the pyrimidines and purines - in peripheral blood mononuclear cells isolated from rDD patients (n=40) and healthy controls (n=46) using comet assay. We also measured DNA damage evoked by hydrogen peroxide and monitored changes in DNA damage during repair incubation.

Results: We found an increased number DNA breaks, alkali-labile sites, and oxidative modification of DNA bases in the patients compared to the controls. Exposure to hydrogen peroxide evoked the same increased damage in both groups. Examination of the repair kinetics of both groups revealed that the lesions were more efficiently repaired in the controls than in the patients.

Conclusions: For the first time we showed that patients with depression, compared with non-depresses individuals, had more DNA breaks, alkali-labile sites, and oxidative DNA damage, and that those lesions may be accumulated by impairments of the DNA repair systems. More studies must be conducted to elucidate the role of DNA damage and repair in depression.

Keywords:
Depression, DNA Damage, DNA Repair, Oxidative Stress, Reactive Oxygen Species

57.Kwiatkowski D., Śliwiński T., Naprawa DNA przez wycinanie zasad azotowych w chorobie Alzheimera, POSTĘPY HIGIENY I MEDYCYNY DOŚWIADCZALNEJ, ISSN: 0032-5449, DOI: 10.5604/17322693.1114036, Vol.68, pp.976-986, 2014
Kwiatkowski D., Śliwiński T., Naprawa DNA przez wycinanie zasad azotowych w chorobie Alzheimera, POSTĘPY HIGIENY I MEDYCYNY DOŚWIADCZALNEJ, ISSN: 0032-5449, DOI: 10.5604/17322693.1114036, Vol.68, pp.976-986, 2014

Abstract:
Choroba Alzheimera (AD - Alzheimer Disease), jest najczęstszą chorobą neurodegeneracyjną u ludzi powyżej 65 roku życia. Szacunkowe dane podają, że na AD w Polsce choruje prawie 200 tys. osób, natomiast na świecie na ten typ schorzenia cierpi około 30 mln ludzi. Progno¬zy wskazują, że w krajach rozwiniętych liczba osób dotkniętych chorobami otępiennymi, w tym AD do 2025 r. wzrośnie od kilkudziesięciu do kilkuset procent w porównaniu do 1980 r. Patogeneza AD nadal nie została do końca wyjaśniona, a wyniki badań przeprowadzonych do tej pory sugerują jej wieloczynnikowość, w której istotną rolę odgrywają wiek oraz czyn-niki genetyczne i środowiskowe. Istnieją przesłanki wskazujące związek między oksydantami wprowadzającymi uszkodzenia do materiału genetycznego oraz zmniejszeniem aktywności enzymów odpowiedzialnych za ich naprawę, a zmianami neurodegeneracyjnymi. W pracy omówiono doniesienia literaturowe obejmujące związek między poziomem aktywności głów¬nego systemu usuwającego uszkodzenia oksydacyjne DNA, czyli systemu naprawy DNA przez wycinanie zasad azotowych (BER - Base Excision Repair) a występowaniem AD. Podkreśla się także istotną rolę zmienności w genach kodujących białka BER, w modulowaniu aktywności tego systemu naprawy DNA. Wskazuje to na możliwość poznania mechanizmu powstawania AD opartego o system BER, co w przyszłości może się przyczynić do określenia molekularnych markerów tego schorzenia.

Keywords:
choroba Alzheimera, oksydacyjne uszkodzenia DNA, naprawa DNA przez wycinanie zasad azotowych, polimorfizm genetyczny

58.Urban B., Engelmann P., Kossecka E., Kosny J., Arranging Insulation for Better Thermal Resistance in Concrete and Masonry Wall Systems, 9th Nordic Symposium on Building Physics – NBS 2011, 2011-05-29/06-02, Tampere (FI), No.3, pp.1-9, 2011
Urban B., Engelmann P., Kossecka E., Kosny J., Arranging Insulation for Better Thermal Resistance in Concrete and Masonry Wall Systems, 9th Nordic Symposium on Building Physics – NBS 2011, 2011-05-29/06-02, Tampere (FI), No.3, pp.1-9, 2011

Abstract:
This paper investigates how the spatial arrangement of thermal insulation influences the overall thermal resistance of concrete and masonry wall systems. Multi-dimensional finite difference modeling was used for this purpose. Concrete masonry units (CMUs) are commercially produced in various geometries and with different weight concretes. Although insulation inserts can increase a CMUs thermal performance, thermal bridging through the solid webbing of the CMUs can greatly reduce the effectiveness of the integrated insulation. Different commercially available CMU geometries and concrete weights were investigated using finite difference modeling to show the impact on overall CMU R-value and to determine the thermal efficiency of the insulation inserts.

Keywords:
thermal insulation, building envelope, masonry, concrete, thermal performance

59.Postek E., Design Sensitivity of a Tensegrity Model of a Tissue, CMM 2011, 19th International Conference on Computer Methods in Mechanics, 2011-05-09/05-12, Warszawa (PL), pp.1-6, 2011
Postek E., Design Sensitivity of a Tensegrity Model of a Tissue, CMM 2011, 19th International Conference on Computer Methods in Mechanics, 2011-05-09/05-12, Warszawa (PL), pp.1-6, 2011

Abstract:
The design sensitivity algorithm for visco-elastic tensegrity structures is presented. We adopt Updated Lagrangian formulation. We have possibility of grouping of the design variables what is particularly useful in the case of hierarchical structures. In our case, the structure is the tissue built of elementary cells. The design sensitivity procedure is implemented with parallel solver.

Keywords:
computational biology, tensegrity structures, design sensitivity

60.Postek E., Smallwood R., Hose R., Finite deformation based model of cytoskeleton, ICCB2009, IV International Congress on Computational Bioengineering including the first European Symposium on Biomedical Integrative Research , 2009-09-16/09-18, Bertinoro (IT), DOI: 10.6092/unibo/amsacta/2646, pp.53-53, 2009
Postek E., Smallwood R., Hose R., Finite deformation based model of cytoskeleton, ICCB2009, IV International Congress on Computational Bioengineering including the first European Symposium on Biomedical Integrative Research , 2009-09-16/09-18, Bertinoro (IT), DOI: 10.6092/unibo/amsacta/2646, pp.53-53, 2009

Abstract:
The cytoskeleto is modelled as a tensegrity structure. It consists of tendons and struts [Stamenovic, 2005]. The basic tensegrity structures are developed from icosahedron.
The cells undergo finite deformations behaviour and their response to loading conditions is visco-elastic,
These types of structures are sensitive to initial prestressing what it intuitively natural since without the initial stress state they would not exist, The other factors affecting the mechanical behaviour of the cell are constitutive parameters and positions of the nodes, in fact, the shape of the cell.

Keywords:
cytoskeleton, visco-elasticity, finite strains, prestressing

61.Postek E., Parallel version of a design sensitivity tensegrity code, TAM 2009, Transnational Access Meeting, HPC-Europa2 2009, 2009-10-14/10-16, Montpellier (FR), pp.1-1, 2009
Postek E., Parallel version of a design sensitivity tensegrity code, TAM 2009, Transnational Access Meeting, HPC-Europa2 2009, 2009-10-14/10-16, Montpellier (FR), pp.1-1, 2009

Abstract:
The cytoskeleton is a tensegrity structure, The mechanics is important to the cells: "change the mechanical stresses on cancer cells and they can start to behave like healthy ones" [1] . The displacements and stresses change in the biological materials due to the growth, division and death of the cells. The cells receive signals for the actions. This constitutes the agent-stress based models of the tissue. [1] C. Ainsworth. Stretvhing the examination, Nature, 456, Dec., 696-699, 2008.

Keywords:
cell mechanics, signals, design sensitivity

62.Postek E.W., Houseman G.A., Jimack P.K., Generic Models of Linear and Non-linear Visco-elastic Surface Deformation above a Fault, EGU 2008, European Geosciences Union General Assembly 2008, 2008-04-13/04-18, Vienna (AT), pp.1-1, 2008
Postek E.W., Houseman G.A., Jimack P.K., Generic Models of Linear and Non-linear Visco-elastic Surface Deformation above a Fault, EGU 2008, European Geosciences Union General Assembly 2008, 2008-04-13/04-18, Vienna (AT), pp.1-1, 2008

Abstract:
The ground displacements measured in the vicinity of a large strike-slip earthquake are
potentially important in diagnosing the state of stress on the fault and in the medium
surrounding. The co-seismic displacement is determined by the immediate elastic response
of the medium and the slip function on the fault-surface. The post-seismic
displacement is determined by a combination of post-seismic creep on the fault, viscoelastic
relaxation in the surrounding medium, and possibly poro-elastic deformation.
There are strong indications from previous earthquake studies that the visco-elastic
relaxation involves non-linear mechanisms, which produce faster deformation in the
early stages and slower deformation in the later stages than would occur with a linear
creep mechanism. In this study we examine a simplified model of a strike-slip fault
cutting a 3D block, and compute the surface displacement versus time functions for
a range of different constitutive relations. We examine linear and non-linear Maxwell
visco-elasticity, and compare with the generalized linear Maxwell visco-elasticity. The
effect of non-linearities in the elasticity (finite strain theory) is also considered.We use
the von Mises flow function in describing the non-linear Maxwell visco-elastic creep
models in which viscous creep strain-rate is proportional to the nth power of the deviatoric
stress (formulated using the 2nd invariant of the stress tensor). We describe
analytical solutions used to validate the 3D code, and then consider the effect of the
exponent n on the time histories of the surface displacement fields above the fault.
We aim here to compare these numerical models with observations from actual fault
systems obtained using InSAR and GPS data. Among the factors affecting the surface deformation patterns are near-surface layering, and lateral variation of material
properties, as well as irregularities on the fault surface. In principle, the comparison
of observations with theory should provide a better understanding of the physical response
of the sub-surface, together with a better understanding of the earthquake cycle
as it operates on specific fault systems.

Keywords:
surface deformation, seismic cycle, visco-elasticity, numerical models

63.Postek E.W., Houseman G.A., Jimack P.K., Aspects of Non-Newtonian Viscoelastic Deformation Produced by Slip on a Major Strike- slip Fault, AGU FALL MEETING 2008, American Geophysical Union Fall Meeting 2008, 2008-12-15/12-19, San Francisco (US), pp.1-1, 2008
Postek E.W., Houseman G.A., Jimack P.K., Aspects of Non-Newtonian Viscoelastic Deformation Produced by Slip on a Major Strike- slip Fault, AGU FALL MEETING 2008, American Geophysical Union Fall Meeting 2008, 2008-12-15/12-19, San Francisco (US), pp.1-1, 2008

Abstract:
Non-Newtonian flow occurs in crustal deformation processes on the long
timescales associated with large- scale continental deformation, and also
on the short time-scales associated with post-seismic deformation. The
co-seismic displacement is determined by the instantaneous elastic
response of the rocks on either side of the fault surface to the
distribution of slip on the surface of the fault. The post-seismic
deformation is determined by some combination of visco-elastic relaxation
of the medium and post-seismic creep on the fault. The response of the
crust may depend on elastic moduli, Poisson's ratio, temperature, pressure
and creep function parameters including stress exponent, activation
energy, activation volume and viscosity coefficient. We use the von Mises
function in describing the non-linear Maxwell visco-elastic creep models.
In this study we examine a model of a strike-slip fault crossing a 3D
block. The fault slips at time zero, and we solve for the viscoelastic
deformation field throughout the 3D volume using a 3D finite element
method. We perform parametric studies on the constitutive equation by
varying these parameters and the depth of the fault event. Our findings
are focused on the fact that the system is very sensitive to the above
mentioned parameters. In particular, the most important seems to be the
temperature profiles and stress exponent. The activation energy and the
pressure are of lower importance, however, they have their meaning. We
investigated the relaxation times and the deformation patterns. We took
the material properties as typical to dry quartzite and diabase. Depending
on the parameters the surface can be deformed permanently or the
deformation can decrease. We attempt to compare qualitatively the
calculated post-seismic response in terms of the post-seismic displacement
history of the earth's surface with InSAR patterns determined from recent
major strike-slip earthquakes. Quantitative comparison of the observations
with these numerical model results can in principle provide a better
understanding of the physical properties of the sub-surface and further
insight into the diagnostic properties of the earthquake cycles of major
fault systems.

Cite as: Author(s) (2008), Title, Eos Trans. AGU, 89(53), Fall Meet.
Suppl., Abstract T44B-07

Keywords:
rheology, crust, litosphere

64.Postek E.W., Houseman G.A., Jimack P.K., The effect of geometrical nonlinearity in visco-elastic deformation, EGU 2007, European Geosciences Union, General Assembly 2007, 2007-04-15/04-20, Vienna (AT), No.9, pp.03087-03087, 2007
65.Postek E., Houseman G.A., Jimack P.K., Nonlinear effects during post-seismic visco-elastic deformation, IUGG XXIV 2007, International Union of Geodesy and Geophysics General Assembly Earth, Our Changing Planet, 2007-07-02/07-13, Perugia (IT), No.JGS003, pp.207-207, 2007
Postek E., Houseman G.A., Jimack P.K., Nonlinear effects during post-seismic visco-elastic deformation, IUGG XXIV 2007, International Union of Geodesy and Geophysics General Assembly Earth, Our Changing Planet, 2007-07-02/07-13, Perugia (IT), No.JGS003, pp.207-207, 2007

Keywords:
deformation, viscosity, power law

66.Postek E., Houseman G.A., Jimack P.K., Surface deformation during earthquake cycle for a layered visco-elastic crust, Ada Lovelace Workshops on Modelling Mantle and Lithosphere Dynamics 10th International Workshop on Modeling of Mantle Convection and Lithospheric Dynamics, 2007-09-02/09-07, Carry-le-Rouet (FR), pp.1-1, 2007
Postek E., Houseman G.A., Jimack P.K., Surface deformation during earthquake cycle for a layered visco-elastic crust, Ada Lovelace Workshops on Modelling Mantle and Lithosphere Dynamics 10th International Workshop on Modeling of Mantle Convection and Lithospheric Dynamics, 2007-09-02/09-07, Carry-le-Rouet (FR), pp.1-1, 2007

Keywords:
surface deformation, viso-elasticity, seismic cycle