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Publications from the year 2018
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Mathematical analysis of a generalised p53-Mdm2 protein gene expression model
- Monika Piotrowska
- Agnieszka Bartłomiejczyk
- Marek Bodnar
We propose the generalisation of the p53-Mdm2 protein gene expression model introduced by Monk (2003). We investigate the stability of a unique positive steady state and formulate conditions which guarantee the occurrence of the Hopf bifurcation. We show that oscillatory behaviour can be caused not only by time lag in protein transcription process, but also can be present in the model without time delay. Moreover, we investigate the stability of new born periodic solutions. Theoretical results are illustrated by numerical simulations and interpreted from the biological point of view.
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Mathematical Modeling of Ice Dynamics as a Decision Support Tool in River Engineering
- Tomasz Kolerski
The prediction of winter flooding is a complicated task since it is affected by many meteorological and hydraulic factors. Typically, information on river ice conditions is based on historical observations, which are usually incomplete. Recently, data have been supplemented by information extracted from satellite images. All the above mentioned factors provide a good background of the characteristics of ice processes, but are not sufficient for a detailed analysis of river ice, which is highly dynamic and has a local extent. The main aim of this paper is to show the possibility of the prediction of ice jams in a river using a mathematical model. The case of the Odra River was used here. Within the Lower and Middle Odra River, the most significant flood risk, in winter conditions, is posed by ice jams created when movable ice is stopped by existing obstacles such as shallow areas in the riverbed, the narrowing of the riverbed, and other obstacles caused as a result of sudden changes of the river current, backwater from sea waters, and north winds, which contribute to the creation of ice jams. This in turn causes the damming of water and flooding of adjacent areas. The DynaRICE model was implemented at two locations along the Odra River, previously selected as ice-prone areas. Also, a thermal simulation of ice cover formation on Lake Dąbie was shown with variable discharge. The results of numerical simulations showed a high risk of ice jamming on the Odra River, created within one day of ice moving downstream. The prediction of the place and timing, as well as the extent, of the ice jam is impossible without the application of a robust mathematical model.
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Mathematical Modeling of the Impact Range of Sewage Discharge on the Vistula Water Quality in the Region of Włocławek
- Piotr Zima
The paper presents results of analysis of the industrial sewage discharge influence at km 688 + 250 of the Vistula River on water quality. During the analysis, two-dimensional models of flow, impurities and temperature transport were used. Hydrological conditions of the analyzed section of the river, characteristic flows and bathymetry of the riverbed in the first instance were defined. Calculations of velocity distribution at steady flow conditions were carried out for the mean of the observed low discharges MLQ = 293 m3 s −1 . For this purpose, a simplified two-dimensional kinematic model for variable depth of flow was used. The analysis of the impact of the discharge of impurities in steady flow conditions was performed by solving an equation of unsteady transport of pollution. Numerical simulations were carried out for pollution in the form of a non-degradable substance (tracer) and water temperature higher than measured in summer and winter conditions. The analysis included distribution of concentration of contaminants at the discharge site, as well as its range along the river bank.
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MEASUREMENT AND ANALYSIS OF ELECTRIC FIELD INTENSITY NEAR SELECTED TRANSMITTERS OF MOBILE TELEPHONY BASE STATIONS
- Martyna Przybyłowicz
- Krzysztof Cwalina
Wireless connectivity has become increasingly common in recent times. Day by day, there are more radiocommunication devices and new ideas for them. In the near future, when the fifth generation networks will be implemented, whose main feature will be continuous wireless communication, we must approach the issue of electric field measurements more and more carefully.
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Measurement of Latency in the Android Audio Path
- Maciej Blaszke
- Dawid Weber
- Szymon Zaporowski
This paper provides a description of experimental investigations concerning comparison between the audio path characteristics of various Android versions. First, information about the changes in each system version in the context of latency caused by them is presented. Then, a measurement procedure employing available applications to measure latency is described comparing to results contained in the Internet. Finally, a comparison between tested systems and results of tests are presented along with conclusions on possible audio processing implementations on the Android platform.
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Mechanical and fracture properties of concrete reinforced with recycled and industrial steel fibers using Digital Image Correlation technique and X-ray micro computed tomography
- Łukasz Skarżyński
- Jan Suchorzewski
Paper presents investigation of fracture phenomenon in plain concrete and in concrete reinforced with both recycled steel fibers (RSF) and industrial steel fibers (ISF). The wedge splitting test (WST), which enables stable crack propagation for quasi-brittle materials, was carried out on 75 75 75 mm cube samples. Initially, fracture process zone development was investigated only on the surface of samples using Digital Image Correlation which is a non-destructive optical testing method. Furthermore, to anal- yse the 3D cracking phenomenon (formation, development, width, shape and curvature) X-ray micro computed tomography was used. Micro-CT images were taken during continuous deformation process - without unloading sample during scanning. X-ray micro-computed tomography was also used to visu- alise and characterise air voids and fibers (length, diameter and orientation) embedded in concrete. The mechanical properties of plain, RSF and ISF reinforced concrete in terms of compressive strength, tensile splitting strength, shrinkage, tensile and residual strength in 3-point bending were additionally described.
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Mechanical properties of polyester reinforced PVC coated fabric subjected to biaxial loading of creep type
- Krzysztof Żerdzicki
- Yago Moreno Jacomini
The goal of the current study is to analyze the basic mechanical properties of the architec-tural fabric VALMEX, which is a composite material built of reinforcing polyester thread families and both sides PVC coated. The material was firstly subjected to biaxial loading of creep type for about 48 hours. The stress levels of the creep loading in two main or-thogonal directions of the fabric (commonly called the warp and fill directions) were in-troduced as follows: 4.6 kN/m, 10.4 kN/m, 16.4 kN/m, 22.4 kN/m, 28.4 kN/m, 34.4 kN/m. After creep loading the specimens were left unloaded for six months and then were subjected to the biaxial tension till rupture. For all the specimens the basic mechanical properties of the material were determined, for the warp and weft directions separately. The change of the obtained parameters shows the influence of biaxial prestress on the me-chanical performance of the VALMEX fabric.
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Mechanical Recycling via Regrinding, Rebonding, Adhesive Pressing, and Molding
- Janusz Datta
- Ewa Głowińska
- Marcin Włoch
Increasing amount of polyurethane foams waste (e.g. from the building or furniture industry) produced every year resulted in the intensive development of their recycling methods. This chapter covers most important mechanical recycling methods, i.e. regrinding, rebonding, adhesive pressing, and molding. The procedure, required equipment and chemicals (if needed) for each method were described. The possible applications of the products obtained by mechanical recycling of polyurethane foams (for example flakes, powders or molded parts) were also presented.
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Mechanism of Binding of Antifungal Antibiotic Amphotericin B to Lipid Membranes: An Insight from Combined Single-Membrane Imaging, Microspectroscopy, and Molecular Dynamics
- Ewa Grela
- Miłosz Wieczór
- Rafał Luchowski
- Joanna Zielinska
- Angelika Barzycka
- Wojciech Grudzinski
- Katarzyna Nowak
- Piotr Tarkowski
- Jacek Czub
- Wieslaw Gruszecki
Amphotericin B is a lifesaving polyene antibiotic used in the treatment of systemic mycoses. Unfortunately, the pharmacological applicability of this drug is limited because of its severe toxic side effects. At the same time, the lack of a well-defined mechanism of selectivity hampers the efforts to rationally design safer derivatives. As the drug primarily targets the biomembranes of both fungi and humans, new insights into the binding of amphotericin B to lipid membranes can be helpful in unveiling the molecular mechanisms underlying both its pharmacological activity and toxicity. We use fluorescence-lifetime-imaging microscopy combined with fluorescence-emission spectroscopy in the microscale to study the interaction of amphotericin B with single lipid bilayers, using model systems based on giant unilamellar liposomes formed with three lipids: dipalmitoylphosphatidylcholine (DPPC), dimirystoylphosphatidylcholine (DMPC), and 1-palmitoyl-2-oleoylphosphatidylcholine (POPC). The results show that amphotericin B introduced into the water phase as a DMSO solution binds to the membrane as dimers and small-molecular aggregates that we identify as tetramers and trimers. Fluorescence-detected linear-dichroism measurements revealed high orientational freedom of all the molecular-organization forms with respect to the membrane plane, which suggests that the drug partially binds to the membrane surface. The presence of sterols in the lipid phase (cholesterol but particularly ergosterol at 30 mol %) promotes the penetration of drug molecules into the lipid membrane, as concluded on the basis of the decreased orientation angle of amphotericin B molecules with respect to the axis normal to the membrane plane. Moreover, ergosterol facilitates the association of amphotericin B dimers into aggregated structures that can play a role in membrane destabilization or permeabilization. The presence of cholesterol inhibits the formation of small aggregates in the lipid phase of liposomes, making this system a promising candidate for a low-toxicity antibiotic-delivery system. Our conclusions are supported with molecular simulations that reveal the conformational properties of AmB oligomers in both aqueous solution and lipid bilayers of different compositions.
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Mechanism of Reduced Sintering Temperature of Al2O3–ZrO2 Nanocomposites Obtained by Microwave Hydrothermal Synthesis
- Iwona Koltsov
- Julita Smalc-Koziorowska
- Marta Prześniak-Welenc
- Maria Małysa
- Giora Kimmel
- Jessica McGlynn
- Alexey Ganin
- Swietlana Stelmakh
A novel method to obtain Al2O3–ZrO2 nanocomposites is presented. It consists of the co-precipitation step of boehmite (AlO(OH)) and ZrO2, followed by microwave hydrothermal treatment at 270 ◦ C and 60 MPa, and by calcination at 600 ◦ C. Using this method, we obtained two nanocomposites: Al2O3–20 wt % ZrO2 and Al2O3–40 wt % ZrO2. Nanocomposites were characterized by Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and transmission electron microscopy. Sintering behavior and thermal expansion coefficients were investigated during dilatometric tests. The sintering temperatures of the nanocomposites were 1209 ◦ C and 1231 ◦ C, respectively—approximately 100 ◦ C lower than reported for such composites. We attribute the decrease of the sintering temperature to the specific nanostructure obtained using microwave hydrothermal treatment instead of conventional calcination. Microwave hydrothermal treatment resulted in a fine distribution of intermixed highly crystalline nanoparticles of boehmite and zirconia. Such intermixing prevented particle growth, which is a factor reducing sintering temperature. Further, due to reduced grain growth, stability of the θ-Al2O3 phase was extended up to 1200 ◦ C, which enhances the sintering process as well. For the Al2O3–20 wt % ZrO2 composition, we observed stability of the zirconia tetragonal phase up to 1400 ◦ C. We associate this stability with the mutual separation of zirconia nanoparticles in the alumina matrix.
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Mechanizmy bezpieczeństwa w strefie C systemu netBaltic
- Tomasz Gierszewski
W artykule zaprezentowano rozwiązania zaimplementowane do zabezpieczania komunikacji w warunkach sporadycznej i nieciągłej łączności (Delay Tolerant Networking – DTN) w systemie netBaltic - charakterystycznej dla strefy C tego systemu. Ze względu na dużą różnorodność rozważanych mechanizmów komunikacyjnych, architektura bezpieczeństwa całego systemu została podzielona na kilka elementów – infrastrukturę klucza publicznego (PKI), bezpieczeństwo systemowe węzłów, zabezpieczanie komunikacji w modelu samoorganizującej się wieloskokowej sieci kratowej (strefy A i B), a także sieci niewrażliwej na opóźnienia (strefa C). W artykule skupiono się na zabezpieczeniu komunikacji w strefie C oraz tematyce zarządzania tożsamością.
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Mechanizmy obsługi mobilności węzłów systemu netBaltic wykorzystujące heterogeniczne systemy transmisji bezprzewodowej
- Michał Hoeft
- Józef Woźniak
Wykorzystanie sieci heterogenicznych integrujących różne techniki transmisji niesie za sobą istotne korzyści. Jedną z nich jest możliwość lepszego zaprojektowania sieci bezprzewodowej, ukierunkowanego na zróżnicowane potrzeby potencjalnych odbiorców. Heterogeniczność wprowadza jednakże nowe wymagania dotyczące mechanizmów obsługi mobilności i realizacji przełączania w warstwie sieciowej. W artykule zaprezentowano scenariusze zastosowania systemów heterogenicznych z uwzględnieniem kontekstu komunikacji morskiej. Omówiono etapy realizacji przełączania oraz przedstawiono podstawową klasyfikację metod wyboru łącza. Dodatkowo zaprezentowano wyniki testów laboratoryjnych i testów morskich mechanizmów obsługi mobilności zaprojektowanych na potrzeby realizacji przełączeń w systemie netBaltic. W artykule zaprezentowano scenariusze zastosowania systemów heterogenicznych z uwzględnieniem kontekstu komunikacji morskiej. Omówiono etapy realizacji przełączania oraz przedstawiono podstawową klasyfikację metod wyboru łącza. Dodatkowo zaprezentowano wyniki testów laboratoryjnych i testów morskich mechanizmów obsługi mobilności zaprojektowanych na potrzeby realizacji przełączeń w systemie netBaltic.
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Mechanizmy wsparcia polityki prorodzinnej w Polsce po roku 2015 na tle krajów Unii Europejskiej
- Piotr Kasprzak
- Wojciech Wyrzykowski
We współcześnie obowiązujących systemach podatkowych krajów Unii Europejskiej istnieją różne rozwiązania związane z preferencyjnym, prorodzinnym, opodatkowaniem dochodów lub dodatkami związanymi z wychowaniem dzieci. Są one ważnym, jeśli nie podstawowym elementem prowadzonej społecznej polityki prorodzinnej. Z uwagi na to, że podatki dochodowe nie są przedmiotem pełnej harmonizacji na obszarze Unii, to w ich formy w poszczególnych krajach są zróżnicowane. Demograficzny problem spadku dzietności jest jednak właściwy dla wszystkich krajów co powoduje, że intensywność i skala działań prorodzinnych jest rosnąca. Celem artykułu jest prezentacja i ocena polityki prorodzinnej prowadzonej w Polsce od roku 2015 na tle państw Unii Europejskiej. Wybór takiego okresu nie jest przypadkowy, bowiem od trzech lat w Polsce władzę sprawuje rząd, który dokonał szeregu zmian w polityce społecznej, ze szczególnym uwzględnieniem polityki prorodzinnej. Autorzy artykułu dokonali oceny dostępnych w Polsce i wybranych krajach Wspólnoty ulg i zwolnień podatkowych, a także bezpośrednich transferów pieniężnych. Uzupełnieniem analizy są studia literaturowe w obszarze teorii opodatkowania rodziny, jej dochodów i mechanizmów wsparcia polityki prorodzinnej.
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Meconium analysis as a promising diagnostic tool for monitoring fetal exposure to toxic substances: Recent trends and perspectives
- Mateusz Kacper Woźniak
- Ewa Jaszczak-Wilke
- Marek Wiergowski
- Żaneta Polkowska
- Jacek Namieśnik
- Marek Biziuk
Prenatal exposure to toxic substances is an important public health problem. Many biological specimens obtained from the fetus or mother are used for biomonitoring. Each material reflects exposure in a specific time period and has different advantages and disadvantages in terms of accuracy, time window of detection and cost/benefit ratio. Recently, meconium has become the matrix of choice in toxicology screening for detecting exposure to xenobiotics. Alcohol metabolites and illicit drugs, pharmaceuticals, nicotine, heavy metals, persistent organic pollutants and their metabolites have been detected in meconium samples. Meconium testing is non-invasive, highly accurate and able to detect prior exposure in utero from 12 to 13 weeks of gestation. This paper reviews current studies focused on meconium analysis for the assessment of fetus exposure to xenobiotics. Analytical procedures for the determination of these compounds and their metabolites and the possibilities and limitations of their use in clinical toxicology are also presented and discussed.
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Media architecture for post-modern society - new forms of participation
- Karolina Życzkowska
The article shows the relationship between the characteristics of the post-modern society, and the development of media architecture with the function of interactivity. In this context, the duality of the features of post-modern society was emphasized: taking into account its location between creativity and consumerism, as well as on the border between the real and virtual word. The development of media architecture has been linked also to the city development models derived from the Smart City concepts, open to innovation, participation and visualization of data through media solutions. Based on 15 representative cases of solutions in the field of media architecture with an interactive function, the article presents new forms of participation in the city space, depending on the interactive scenario and the type of embedded interfaces. Solutions chosen for analysis play an important role in the night image of the cities, becoming events in commercial spaces - in line with the concept of a city of sensations. The article shows the relationship between the scope of the media solution, the specificity of the interaction, and the vitality of space within the media architecture solutions. The research takes into account the visual effects transmitted on media surfaces and the spatial context of media interactive solutions.
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Medytacje Fibonacciego + sztruksowy zając / wobec Katarzyny Kobro (1898-1951)
- Krzysztof Wróblewski
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Membrane model of human abdominal wall. Simulations vs. in vivo measurements
- Izabela Lubowiecka
- Agnieszka Tomaszewska
- Katarzyna Szepietowska
- Czesław Szymczak
- Monika Lichodziejewska-Niemierko
- Michał Chmielewski
The study presents a methodology of defining a numerical model of human abdominal wall based on the experimentally registered data of the abdomen geometry due to variations of the intraabdominal pressure. The abdominal wall is modelled here as a simple homogeneous membrane structure made of linear orthotropic material The displacements registered during the increase of pressure are compared with the re-sults of the model static simulations.
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MEMORYSCAPES OF EASTERN POLAND
- Joanna Kabrońska
The text investigates new phenomena emerging in the field of social memory and commemoration in contemporary Poland. On the basis of field analyses, case studies and theoretical, transdisciplinary approaches, the paper discusses the issue of contemporary memoryscapes in eastern Poland (Bialystok and Lublin). These emerging forms of remembrance are the result of the sophisticated interplay between different actors involved in the social discourse of memory: witnesses and their testimonies, historical artefacts, architectural objects, new spaces of remembrance and many others. The research provides insights both into the concept of ‘memoryscapes’ and the process of their formation. The text concludes with an attempt to present various material forms of commemoration as an important part of the social landscape in contemporary Poland. The research findings offer the opportunity to introduce new interpretations of the complex and difficult relation between memory and architecture to academic discourse. The text stresses that today the study of memory forms would be difficult without transdisciplinary approaches. There is a need for further research, but the paper confirms the potential of this direction of study
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MEMS Technology Quality Requirements as Applied to Multibeam Echosounder
- Krzysztof Bikonis
- Jerzy Demkowicz
Small, lightweight, power-efficient, and low-cost microelectromechanical system (MEMS) inertial sensors and microcontrollers, available in the market today, help reduce the instability of Multibeam Sonars. Current MEMS inertial measurement units (IMUs) come in many shapes, sizes, and costs — depending on the application and performance required. Although MEMS inertial sensors offer affordable, appropriately scaled units, they are not currently capable of meeting all requirements for accurate and precise attitudes, due to their inherent measurement noise. The article presents the comparison of different MEMS technologies, and their parameters regarding to the main application namely, Multibeam Echo Sounders (MBES). The MEMS parameters’ quality are crucial for further MBES record- processing, the article presents the results of undertaken researches in that area, and the results are relatively positive for low-cost MEMS. The paper undertake some vital aspect of using MEMS in attitude and heading reference system (AHRS) context. The article presents a few aspects of MEMS gyro errors and their estimation process in the context of INS processing flow as well, pointing out the main difficulties behind the INS when using a few top MEMS technologies.
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Mercury concentration and the absolute and relative sizes of the internal organs in cormorants Phalacrocorax carbo (L. 1758) from the breeding colony by the Vistula Lagoon (Poland)
- Małgorzata Misztal–Szkudlińska
- Elżbieta Kalisińska
- Piotr Szefer
- Piotr Konieczka
- Jacek Namieśnik
This work analyses the effect of mercury on the condition of cormorants (Phalacrocorax carbo) from an extensive breeding colony in northern Poland, the largest in Europe. A total of 55 birds (44 adults and 11 immature) were obtained. Total mercury (Hg) concentrations were measured in the liver, kidneys, breast muscles, heart, gullet (oesophagus), stomach, intestines, trachea, lungs and eyeballs. The total body mass (TBM) and empty body mass (EBM) were measured, and the body parts taken for analysis were weighed. The relative mass of the tissues and the L/K index were expressed as percentages. Based on the L/K index the birds were divided into three condition classes: (A) very good, (B) good and (C) moderate. The mean TBM and EBM in these cormorants were 2286 and 2184 g respectively. The greatest contributions to EBM were from the breast muscles (~11%), liver (3.7%) and intestines (3.0%). The stomach, gullet, lungs, heart and kidneys made up from ~1.0–2.8% EBM, and the trachea and eyeballs < 0.4%. 31 of the 55 birds analysed were allocated to class B; mean Hg levels in them were the highest in the kidneys, liver, lungs and muscles (18.3, 9.78, 2.70, 1.86 µg/g dw respectively); they were ≤ 1 µg/g in the other tissues. In ecotoxicology it is assumed that a hepatic concentration > 16.7 µg Hg/g dw can lead to adverse effects in the reproduction of non-marine birds. In the light of the present results, the reproductive parameters of the cormorants from the colony in northern Poland, though mostly in good or very good condition, may be depressed as a result of elevated Hg levels in their body tissues.