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Repozytorium publikacji
Politechniki Gdańskiej

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  • Badania skuteczności ochrony katodowej Nabrzeża Zachodniego odcinek nr 1 (południowy) oraz Pomostu A w Porcie Gdynia
    • Krzysztof Żakowski
    • Juliusz Orlikowski
    • Kazimierz Darowicki
    2021

    Zbadano skuteczność ochrony katodowej południowego odcinka nabrzeża zachodniego oraz pomostu A w Porcie Wojennym w Gdyni. Ochrona realizowana jest za pomocą aluminiowych anod galwanicznych spawanych do ścianki szczelnej oraz pali.

  • Badania skuteczności ochrony katodowej Nabrzeża Zachodniego odcinek nr 2 (północny) oraz Pirsu C w Porcie Gdynia
    • Krzysztof Żakowski
    • Juliusz Orlikowski
    • Kazimierz Darowicki
    2021

    Zbadano skuteczność ochrony katodowej północnego odcinka nabrzeża zachodniego oraz pomostu C w Porcie Wojennym w Gdyni. Ochrona realizowana jest za pomocą aluminiowych anod galwanicznych spawanych do ścianki szczelnej oraz pali.

  • Badania skuteczności ochrony katodowej Ostrogi Pilotowej w Porcie Gdynia
    • Krzysztof Żakowski
    • Kazimierz Darowicki
    2021

    Przedmiotem opracowania jest ocena skuteczności ochrony katodowej palościanki Ostrogi Pilotowej w Porcie Wojennym w Gdyni Oksywiu. Ochrona realizowana jest za pomocą aluminiowych anod galwanicznych spawanych do ścianki.

  • Badania wytrzymałościowe zgrzein łączących pręty zbrojeniowe o średnicy Ø30mm
    • Wojciech Kiełczyński
    • Ryszard Buza
    2021

    Zakres badań dotyczy oceny wytrzymałościowej zgrzein doczołowych, wykonanych metodą zwarciową. Elementami zgrzewanymi były pręty zbrojeniowe o średnicy Ø30mm. Badania związane są z okresową kontrolą stabilności parametrów zgrzewarki, szczególnie w odniesieniu do górnych, dopuszczalnych przez producenta zakresów parametrów zgrzewania oraz analizą wyników i porównaniu rezultatów prób wytrzymałościowych uzyskanych w 2019 i 2020 w trakcie wdrażania technologii.

  • BADANIE ZABEZPIECZEŃ MODUŁÓW WYTWARZANIA ENERGII ZGODNIE Z WYMAGANIAMI KODEKSU SIECI RfG
    • Mirosław Włas
    • Kacper Chyła
    2021 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    Celem zapewnienia bezpieczeństwa systemu elektroenergetycznego w ramach systemu wzajemnie połączonego, niezbędnym jest ustalenie jednakowych wymogów mających zastosowanie do modułów wytwarzania energii. W tym celu ustanowiony został kodeks sieci RfG dotyczący wymogów w zakresie przyłączania jednostek wytwórczych do sieci. W pracy przedstawione zostały wymagania kodeksu sieci RfG wobec zabezpieczeń źródeł wytwórczych. Na stanowisku badawczym przeprowadzono próby działania zabezpieczeń z wykorzystaniem przekaźnika zabezpie-czeniowego REX 640 na modelu sieci oraz wykonana została komunikacja z nadrzędnym systemem SCADA wykorzystując protokół IEC 61850. Przeprowadzone badania są niezbędne do złożenia dokumentu PGMD zezwalającego na eksploatację modułu wytwarzania energii.

  • Badanie zdolności do odkształcenia plastycznego kątowych próbek spawanych o zmiennej geometrii połączenia i różnym wkładem ciepła (energii liniowej)
    • Wojciech Kiełczyński
    • Jacek Haras
    • Marek Chodnicki
    2021

    Przedmiotem badań były próbki dostarczone przez Zleceniodawcę wykonane w rożnych warunkach cieplnych i geometrycznych. W tej części pracy próbki poddano badaniom mającym stwierdzić ich zdolność do odkształceń plastycznych. 3. Przeprowadzone w tych samych warunkach próby badania zdolności spoin, a szczególnie grani do odkształcenia plastycznego ujawniły, że jakość połączeń zrealizowanych wg wariantu zmodyfikowanego jest wyższa niż w przypadku wariantu bez modyfikacji. Świadczą o tym badania wizualne rozciąganych powierzchni grani spoiny.

  • Bariery i ograniczenia wdrażania technologii BIM- wyniki badań pilotażowych
    • Waldemar Kosiedowski
    • Marek Wirkus
    2021 Pełny tekst Builder

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  • Bariery rozwoju bioekonomii w Polsce
    • Roksana Bochniak
    • Aleksandra Gołąbek
    • Paweł Dąbrowski
    • Dariusz Mikielewicz
    2021 Przegląd Komunalny

    W Polsce sytuacja ponownego wykorzystania odpadu celem produkcji nowych produktów nie jest obecnie do końca uregulowana prawnie. Nie obserwuje się wielu dobrych praktyk w przedsiębiorstwach. Wartościowe odpady poprodukcyjne są wykorzystywane na cele energetyczne bądź jako nawóz dla roślin lub pasza dla zwierząt. W celu zlokalizowania barier w rozwoju bioekonomii przeprowadzono wywiady z osobami bezpośrednio związanymi z kwestiami dotyczącymi tego zagadnienia.

  • Baseline-free debonding detection in reinforced concrete structures by elastic wave propagation
    • Beata Zima
    • Rafał Kędra
    2021 Pełny tekst MEASUREMENT

    The article presents the results of the numerical and experimental analysis concerning wave propagation in reinforced concrete (RC) beams with various extent of debonding between the steel rod and concrete cover. The main aim of the paper was to consider the unsolved research gaps, which considerably limit the application of wave-based methods in practice. The propagation of the flexural wave modes excited and registered on the outer surface of the concrete cover in RC beams with various damage sizes were considered. The phenomenon of flexural wave propagation in a damaged beam was described theoretically and the relationship between damage size and wave velocity was proposed. Next, the theoretical predictions were examined experimentally. The research allows to observe the variability of the velocity of a wave propagating in various regions of the monitored specimen. The differences between times of flight allow to determine the localization of the debonded rod. The study indicates that the debonding size can be successfully determined if the velocities of flexural wave modes in the concrete specimen as well as in separated reinforcing rod are known.

  • Baza polityk wydawniczych i repozytorium Open Access – uzupełniające się elementy
    • Joanna Błasiok
    • Agnieszka Szymik
    2021 Pełny tekst

    Przedstawiono korzyści płynące z tworzenia i wykorzystywania bazy polityk wydawniczych polskich czasopism naukowych dla różnych interesariuszy, takich jak wydawcy, redaktorzy, naukowcy i bibliotekarze. Omówiono podstawowe zadania i funkcje bazy, tak aby ukazać ją jako kompleksowe źródło informacji o polityce wydawniczej polskich czasopism. Gromadzone w bazie informacje stanowią istotną pomoc w ustalaniu zasad samoarchiwizacji publikacji w repozytoriach naukowych. Na przykładzie deponowania materiałów w repozytorium MOST Wiedzy opisano wykorzystanie bazy w praktyce.

  • Bead-on-Plate Underwater Wet Welding on S700MC Steel
    • Jacek Tomków
    • Aleksandra Świerczyńska
    • Michał Landowski
    • Adrian Wolski
    • Grzegorz Rogalski
    2021 Pełny tekst Advances in Science and Technology Research Journal

    The participation of high strength steels in marine and offshore structures is increasing, which makes it necessary to develop recommendations for underwater repair welding works. The article presents the results of bead-on-plate welded specimens made of S700MC high strength steel in underwater wet welding conditions by covered elec- trodes. Three specimens with heat input values in the range 0.91-1.05 kJ/mm were made. The specimens were sub- jected to visual, metallographic, macro- and microscopic tests as well as hardness measurements using the Vickers method. It was found that the higher heat input leads to formation of mixed bainite-martensite microstructure in the heat-affected zone (HAZ). Lower heat input value results in presence of martensite in HAZ. It was shown that in the scope of the performed tests, the maximum hardness of HAZ did not exceed the critical value for the material group, and the increase in heat input caused the decrease of hardness by about 25 HV10 to a level 250-260 HV10.

  • Bee Bread Exhibits Higher Antimicrobial Potential Compared to Bee Pollen
    • Karolina Pełka
    • Olga Otłowska
    • Randy Worobo
    • Piotr Szweda
    2021 Pełny tekst Antibiotics-Basel

    This study aimed at investigation of the antimicrobial potential of ethanolic extracts of bee bread (BB) and bee pollen (BP) and suspensions of these products in MHB (Mueller Hinton Broth). We covered 30 samples of BP and 19 samples of BB harvested in Polish apiaries. Slightly lower activity was observed against Gram-negative bacteria compared to Gram-positive staphylococci. BB extracts exhibited higher inhibitory potential with minimum inhibitory concentration (MIC) values in the range from 2.5 to 10% (v/v) against Staphylococcus aureus ATCC 25923 and ATCC 29213. Most active BB extracts, namely, BB6, BB11 and BB19, effectively inhibited growth of clinical isolates of S. aureus (n = 9), including MRSA (methicillin resistant Staphylococcus aureus) strains (n = 3) at concentrations ranging from 2.5 to 5.0% (v/v). Minimal bactericidal concentration (MBC) values were in the same range of concentrations; however, a shift from 2.5 to 5.0% (v/v) was observed for some products. The most active BP extracts inhibited the growth of reference strains of S. aureus at a concentration of 5% (v/v). Up to the concentration of 20% (v/v) three and seven BP extracts were not able to inhibit the growth of S. aureus ATCC 29213 and S. aureus ATCC 25923 respectively. The growth of staphylococci was also importantly inhibited in suspensions of the products in MHB. No correlation between phenolic content and antimicrobial activity was observed

  • Bee Pollen and Bee Bread as a Source of Bacteria Producing Antimicrobials
    • Karolina Pełka
    • Randy Worobo
    • Justyna Walkusz
    • Piotr Szweda
    2021 Pełny tekst Antibiotics-Basel

    The principal objective of the study was the isolation and identification of bacteria that are present in mature bee bread (BB) and dried (ready for selling and consumption) bee pollen (BP). Obtained isolates were screened for their potential to inhibit select human pathogenic bacteria and their ability to produce enzymes of particular industrial importance. Four and five samples of BP and BB, respectively, were used for the study. In total, 81 strains of bacteria were isolated, and 34 (42%) of them exhibited antagonistic interactions with at least one reference strain of pathogenic bacteria, namely Staphylococcus aureus ATCC 25923, Staphylococcus aureus ATCC 29213, Staphylococcus epidermidis 12228, Pseudomonas aeruginosa ATCC 27857, and Escherichia coli ATCC 25922. The sequencing of the 16S rRNA gene revealed that all strains producing antimicrobials belong to the genus Bacillus spp., and among them, five species were identified: B. pumilus (n = 17), B. altitudinis (n = 9), B. licheniformis (n = 4), B. subtilis (n = 2), and B. safensis (n = 1). Furthermore, 69, 54, 39, and 29 of the strains exhibited lipolytic, proteolytic, cellulolytic, and esterolytic activity, respectively. Alpha amylase and beta galactosidase activity were rarely observed, and none of the strains produced laccase. The outcomes of the study revealed that BP and BB can be considered potential sources of bacteria producing antimicrobial agents and/or enzymes of particular industrial importance. Of course, additional research is required to verify this hypothesis, but the results of preliminary studies are promising.

  • Behavior of residual current devices at frequencies up to 50 kHz
    • Stanisław Czapp
    • Hanan Tariq
    2021 Pełny tekst ENERGIES

    The use of residual current devices (RCDs) is obligatory in many types of low-voltage circuits. They are devices that ensure protection against electric shock in the case of indirect contact and may ensure additional protection in the case of direct contact. For the latter purpose of protection, only RCDs of a rated residual operating current not exceeding 30 mA are suitable. Unfortunately, modem current-using equipment supplied via electronic converters with a pulse width modulation produces earth fault currents composed of high-frequency components. Frequency of these components may have even several dozen kHz. Such components negatively influence the RCDs’ tripping level and, hence, protection against electric shock may be ineffective. This paper presents the results of the RCDs’ tripping test for frequencies up to 50 kHz. The results of the test have shown that many RCDs offered on the market are not able to trip for such frequencies. Such behavior was also noted for F-type and B-type RCDs which are recommended for the circuits of high-frequency components. Results of the test have been related to the requirements of the standards concerning RCDs operation. The conclusion is that these requirements are not sufficient nowadays and should be modified. Proposals for their modification are presented.

  • Benchmarking Scalability and Security Configuration Impact for A Distributed Sensors-Server IOT Use Case
    • Robert Kałaska
    • Paweł Czarnul
    2021 Pełny tekst

    Internet of Things has been getting more and more attention and found numerous practical applications. Especially important in this context are performance, security and ability to cope with failures. Especially crucial is to find good trade-off between these. In this article we present results of practical tests with multiple clients representing sensors sending notifications to an IoT middleware – DeviceHive. We investigate performance under different loads by various numbers of IoT clients and show how various strengths of the hash algorithm affect the performance measured by the number of client requests handled within a predefined time frame.

  • Betaine and L-carnitine ester bromides: Synthesis and comparative study of their thermal behaviour and surface activity
    • Angelica Mero
    • Andrea Mezzetta
    • Janusz Nowicki
    • Justyna Łuczak
    • Lorenzo Guazzelli
    2021 JOURNAL OF MOLECULAR LIQUIDS

    Six esters of both betaine and L-carnitine bromides, featuring alkyl groups ranging from C8 to C18 in length, have been synthesized. The thermal behaviour of these twelve bio-based salts has been analyzed and compared by thermal gravimetric analysis and differential scanning calorimetry. The L-carnitine alkyl ester bromides melted below 100 C and can hence be considered ionic liquids (ILs) with full rights. Conversely, the betaine alkyl ester bromides, with the exception of the shortest member of the series, melted slightly above this upper limit. Also, they resulted less thermally stable when compared to their L-carnitine analogues. Moreover, the self-aggregation behavior of these structurally related betaine and L-carnitine alkyl ester bromides, inspected through surface tension, conductivity measurements and isothermal titration calorimetry, varied significantly. The critical micelle concentration (CMC) values for the L-carnitine series were lower than those of the betaine series, and the former ILs were also capable of adsorbing more efficiently at the air/water interface as well as of reducing surface tension. A potential use of these organic salts as components of deep eutectic solvents is envisaged, thus showcasing the applicability of this natural trimethylammonium cation.

  • Beyond the helium buffer: 12C−2 rotational cooling in cold traps with H2 as a partner gas: interaction forces and quantum dynamics
    • Barry P. Mant
    • Jan Franz
    • Roland Wester
    • Francesco Antonio Gianturco
    2021 Pełny tekst MOLECULAR PHYSICS

    abstract = { The scattering cross-sections and corresponding rate coefficients for rotationally inelastic collisions of $^{12}$C$_2$^-$ ($^2 \Sigma_g^+$) with H$_2$ ($^1 \Sigma_g^+$) are presented over a broad range of cold-trap temperatures. They have been calculated using quantum scattering theory that employs a new ab initio potential energy surface. The rate coefficients for the inelastic processes in the anionic partner are used to model the thermalisation dynamics of $^{12}$C$_2$^-$ using H$_2$ as a buffer gas, a trap partner which is found here to be far more efficient than the typical buffer gas He and even more so than when using Ar as a partner gas. The microscopic physics underlying these findings is discussed in some detail. We additionally compute and discuss $^{12}$C$_2$^-$ quadrupole transitions by spontaneous emission and use the newly computed rates to show that the anion's rotational levels should be in local thermal equilibrium at typical interstellar conditions.

  • Bez tytułu, obraz olejny, 95x80 cm
    • Jan Buczkowski
    2021

    Prezentacja obrazu na wystawie sztuki współczesnej

  • Bezczujnikowe sterowanie pięciofazową maszyną indukcyjną klatkową zasilaną z falownika prądu
    • Filip Wilczyński
    2021 Pełny tekst

    W rozprawie podjęto temat bezczujnikowego sterowania pięciofazową maszyną indukcyjną zasilaną z falownika prądu. Autor rozprawy zaproponował nowe struktury regulacji dla pięciofazowej maszyny indukcyjnej zasilanej z falownika prądu (w podwójnym układzie współrzędnych), które umożliwiają lepsze wykorzystanie obwodu magnetycznego maszyny, poprzez kontrolowaną iniekcję trzeciej harmonicznej prądu. W rozprawie przedstawiono algorytmy wektorowej modulacji szerokości impulsów dla pięciofazowego falownika prądu, pozwalające na niezależne kształtowanie dwóch wektorów prądu wyjściowego falownika. Autor przedstawił wyniki badań symulacyjnych i eksperymentalnych opracowanych struktur regulacji oraz algorytmów modulacji szerokości impulsów. Ponadto, przedstawiono bezczujnikową pracę badanego układu napędowego oraz analizę uzyskanych przebiegów prądu i napięcia stojana pięciofazowej maszyny indukcyjnej zasilanej z falownika prądu.

  • Bias-Dependent Dynamics of Degradation and Recovery in Perovskite Solar Cells
    • M. Prete
    • M. V. Khenkin
    • Damian Głowienka
    • B. R. Patil
    • J. S. Lissau
    • Ilker Dogan
    • Jennie Hansen
    • T. Leißner
    • J. Fiutowski
    • H.-G. Rubahn
    • B. Julsgaard
    • P. Balling
    • V. Turkovic
    • Yulia Galagan
    • E. A. Katz
    • M. Madsen
    2021 Pełny tekst ACS Applied Energy Materials

    Degradation of perovskite solar cells (PSCs) is often found to be partially or fully reversible when the cells are allowed to recover in the dark. Unlike the dynamics of degradation, knowledge about the dynamics of PSC cell recovery is very limited. Here, we demonstrate that the PSC recovery strongly depends on the electrical bias conditions during the light-induced degradation and that it can be manipulated by applying an external electrical bias during the recovery phase. Investigation of the recovery dynamics allows us to analyze the degradation mechanisms in detail. More specifically, we aged a mixed-cation mixed-halide PSC with a n-i-p structure under illumination in open-circuit (OC) or short-circuit (SC) conditions, and periodically measured their characteristics during the recovery. PSCs aged in SC degrade faster and fully recover after the light is switched off, while the performance of the cells aged in OC does not recover but instead further decreases after the light is switched off (“drop-in-dark” effect). With the use of transient photoluminescence, secondary ion mass spectrometry, and drift-diffusion-based simulations, we hypothesize that extrinsic ion migration causes the drop-in-dark effect, by forming an electron extraction barrier at the metal oxide electron transport layer. The applied bias alleviates this effect. Our results are relevant for gaining a deeper understanding of the multiple degradation mechanisms present in perovskite solar cells, and for finding a practical way to assist their recovery.

  • Bicycle Traffic Model for Sustainable Urban Mobility Planning
    • Jacek Oskarbski
    • Krystian Birr
    • Karol Żarski
    2021 Pełny tekst ENERGIES

    Modelling tools and transport models are required to assess the impact of measures for the effective planning of cycling routes in cities. This paper presents the methodology for developing a four-stage macroscopic model of bicycle traffic for the city of Gdynia, and its use in planning new bicycle routes, considering a modal shift. The model presented in this paper allows for the evaluation of the influence of the characteristics of the cycling infrastructure, along with the development of the cycling network based on the choice of cycling as an alternative to other modes of transport, by taking into account the modal shift. The model takes into account the influence of the longitudinal gradient, link, and surface type of cycling routes on the distribution and demand for bicycle traffic. The results of our research allow us to assess the impact of planned cycling routes on the reduction in the volume of car traffic, which is crucial for reducing energy consumption and negative environmental impacts. Experiences from the application of the model in Gdynia suggest that the model provides a strong basis to support mobility planning and monitoring processes in cities worldwide. Cities should take into account the methods proposed in this paper when planning the development of their transport systems.

  • Bifractal receiver operating characteristic curves: a formula for generating receiver operating characteristic curves in credit-scoring contexts
    • Błażej Kochański
    2021 Pełny tekst Journal of Risk Model Validation

    This paper formulates a mathematical model for generating receiver operating characteristic (ROC) curves without underlying data. Credit scoring practitioners know that the Gini coefficient usually drops if it is only calculated on cases above the cutoff. This fact is not a mathematical necessity, however, as it is theoretically possible to get an ROC curve that keeps the same Gini coefficient no matter how big a share of lowest score cases are excluded from the calculation (a “right-hand” fractal ROC curve). Analogously, a left-hand fractal ROC curve would be a curve that keeps its Gini coefficient constant below any cutoff point. The model proposed here is a linear combination of left- and right-hand ROC curves. A bifractal ROC curve is drawn with just two parameters: one responsible for the shape of the curve and the other responsible for the area under the curve (a Gini coefficient). As is shown in this paper, most real-life credit-scoring ROC curves lie between the two fractal curves. In consequence, the Gini coefficient will be consistently lower when computed only on approved loans.

  • Bifurcation of equilibrium forms of a gas column rotating with constant speed around its axis of symmetry
    • Joanna Janczewska
    • Anita Zgorzelska
    2021 Pełny tekst NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS

    We will be concerned with the problem of deformation of the lateral surface of a column that rotates with constant speed around its axis of symmetry. The column is filled by a gas and our goal is to investigate the deformation of the lateral surface depending on the pressure of the gas.

  • Big Data from Sensor Network via Internet of Things to Edge Deep Learning for Smart City
    • Jerzy Balicki
    • Honorata Balicka
    • Piotr Dryja
    2021

    Data from a physical world is sampled by sensor networks, and then streams of Big Data are sent to cloud hosts to support decision making by deep learning software. In a smart city, some tasks may be assigned to smart devices of the Internet of Things for performing edge computing. Besides, a part of workload of calculations can be transferred to the cloud hosts. This paper proposes benchmarks for division tasks between an edge layer and a cloud layer for deep learning. Results of some numerical experiments are presented, too.

  • Bilans energii i ślad węglowy w zrównoważonej gospodarce oczyszczalni ścieków
    • Ewa Zaborowska
    • Mojtaba Maktabifard
    • Jacek Mąkinia
    2021 Forum Eksploatatora

    Dążenie do osiągnięcia zrównoważonego rozwoju stawia przed oczyszczalniami ścieków (OŚ) nowe wyzwania. Oprócz dotrzymywania standardów jakościowych w odpływie, obserwuje się dążenie do samowystarczalności energetycznej. Nowym kryterium oceny jest ślad węglowy (CF) określający skumulowaną emisję gazów cieplarnianych generowanych przez OŚ. Celem artykułu było określenie relacji między bilansem energii a śladem węglowym w zrównoważonej gospodarce miejskich OŚ. Dla sześciu obiektów wyznaczono całkowity CF i jego komponenty oraz zidentyfikowano wrażliwe parametry mogące wpływać na niepewność wyników. W artykule przedstawiono metodę uproszczoną bazującą na współczynnikach emisji oraz pokazano możliwości, jakie daje zastosowanie modelowania komputerowego. Stwierdzono, że zarówno emisje bezpośrednie, jak i pośrednie mogą istotnie wpływać na CF OŚ. Bezpośrednie emisje procesowe dominują w OŚ stosujących odzysk energii z biogazu (62-74%), a emisje pośrednie związane z energią dominują CF w OŚ pokrywających zapotrzebowanie z sieci elektroenergetycznej (69-72%). Wykazano, że wskaźniki procesowych emisji podtlenku azotu są specyficzne dla danego obiektu i należą do najbardziej wrażliwych parametrów wpływających na oszacowanie całkowitego CF. Nie stwierdzono występowania korelacji pomiędzy poziomem samowystarczalności energetycznej a całkowitym CF OŚ. Natomiast silna zależność wiąże samowystarczalność energetyczną ze stosunkiem pośredniej do bezpośredniej emisji gazów cieplarnianych. CF OŚ można obniżyć dzięki zastosowaniu odnawialnych źródeł energii i odzysku energii na miejscu, rolniczemu zagospodarowaniu osadów ściekowych, a także poprzez odpowiednią manipulację parametrów operacyjnych.

  • Binary-Encounter Model for Direct Ionization of Molecules by Positron-Impact
    • Małgorzata Franz
    • Katarzyna Wiciak-Pawłowska
    • Jan Franz
    2021 Pełny tekst Atoms

    We introduce two models for the computation of direct ionization cross sections by positron impact over a wide range of collision energies. The models are based on the binary-encounter-Bethe model and take into account an extension of the Wannier theory. The cross sections computed with these models show good agreement with experimental data. The extensions improve the agreement between theory and experiment for collision energies between the first ionization threshold and the peak of the cross section. The models are based on a small set of parameters, which can be computed with standard quantum chemistry program packages.

  • BINDER COURSES USING COLD RECYCLED MIXTURES – A NOVEL CONCEPT IN COLD RECYCLING
    • Bohdan Dołżycki
    • Andrea Grilli
    • Alex Balzi
    • Mariusz Jaczewski
    • Cezary Szydłowski
    2021

    Cold recycling with cement and bituminous emulsion is one of the most environmentally friendly techniques to maximize the reuse of reclaimed asphalt (RA) collected during demolition of roads. Cold recycled mixtures are commonly used for base courses in construction or rehabilitation of flexible and semi-rigid pavements. Current experiences demonstrated that cold recycling with appropriate requirements and technical recommendations allows long-lasting pavements to be designed. Those outcomes stimulated researchers and engineers in the new challenge of using the cold recycled mixtures in binder layers that are generally more often included in maintenance planning. This paper summarizes current San Marino and Polish experiences with cold recycled mixtures designed for binder layers. The first part of the paper presents the design phase of the cold recycled mixtures in both countries. It describes and compares the composition of the mixtures, grading curves of the mineral mixtures, binding agents and requirements. The second part of the paper shows laboratory test results of mechanical properties of cold recycled mixtures for binder courses including test results in full-scale application.

  • Bioactivities of Phenolic Compounds from Kiwifruit and Persimmon
    • Kim Young-mo
    • Abas Faridah
    • Yong-Seo Park
    • Ang-Kyun Park
    • Kyung-Sik Ham
    • Seong-Gook Kang
    • Martyna Lubinska-Szczygeł
    • Aviva Ezra
    • Shela Gorinstein
    2021 Pełny tekst MOLECULES

    Fruit used in the common human diet in general, and kiwifruit and persimmon particularly, displays health properties in the prevention of heart disease. This study describes a combination of bioactivity, multivariate data analyses and fluorescence measurements for the differentiating of kiwifruit and persimmon, their quenching and antioxidant properties. The metabolic differences are shown, as well in the results of bioactivities and antioxidant capacities determined by ABTS, FRAP, CUPRAC and DPPH assays. To complement the bioactivity of these fruits, the quenching properties between extracted polyphenols and human serum proteins were determined by 3D-fluorescence spectroscopy studies. These properties of the extracted polyphenols in interaction with the main serum proteins in the human metabolism (human serum albumin (HSA), α-β-globulin (α-β G) and fibrinogen (Fgn)), showed that kiwifruit was more reactive than persimmon. There was a direct correlation between the quenching properties of the polyphenols of the investigated fruits with serum human proteins, their relative quantification and bioactivity. The results of metabolites and fluorescence quenching show that these fruits possess multiple properties that have a great potential to be used in industry with emphasis on the formulation of functional foods and in the pharmaceutical industry. Based on the quenching properties of human serum proteins with polyphenols and recent reports in vivo on human studies, we hypothesize that HSA, α-β G and Fgn will be predictors of coronary artery disease (CAD).

  • Bio-Based Polyurethane Networks Derived from Liquefied Sawdust
    • Kamila Gosz
    • Agnieszka Tercjak
    • Adam Olszewski
    • Józef Haponiuk
    • Łukasz Piszczyk
    2021 Pełny tekst Materials

    The utilization of forestry waste resources in the production of polyurethane resins is a promising green alternative to the use of unsustainable resources. Liquefaction of wood-based biomass gives polyols with properties depending on the reagents used. In this article, the liquefaction of forestry wastes, including sawdust, in solvents such as glycerol and polyethylene glycol was investigated. The liquefaction process was carried out at temperatures of 120, 150, and 170 C. The resulting bio-polyols were analyzed for process efficiency, hydroxyl number, water content, viscosity, and structural features using the Fourier transform infrared spectroscopy (FTIR). The optimum liquefaction temperature was 150 C and the time of 6 h. Comprehensive analysis of polyol properties shows high biomass conversion and hydroxyl number in the range of 238–815 mg KOH/g. This may indicate that bio-polyols may be used as a potential substitute for petrochemical polyols. During polyurethane synthesis, materials with more than 80 wt% of bio-polyol were obtained. The materials were obtained by a one-step method by hot-pressing for 15 min at 100 C and a pressure of 5 MPa with an NCO:OH ratio of 1:1 and 1.2:1. Dynamical-mechanical analysis (DMA) showed a high modulus of elasticity in the range of 62–839 MPa which depends on the reaction conditions.

  • Biofilm bakteryjny uropatogennych szczepów E. coli Dr+ jako czynnik indukujący przewlekłość zakażeń dróg moczowych ograniczający ich leczenie
    • Beata Zalewska-Piątek
    • Rafał Piątek
    2021 Postępy Mikrobiologii

    Zakażenia dróg moczowych (ZUM) stanowią jedne z najczęściej występujących infekcji bakteryjnych, dotykających każdego roku miliony osób na świecie. Problematyka tych zakażeń wynika z ich przewlekłości i nawrotów, pomimo stosowania terapii antybiotykowej oraz ciągle wzrastającej lekooporności uropatogenów je wywołujących. Dominującym czynnikiem etiologicznym ZUM są uropatogenne szczepy E. coli (UPECs), wykazujące zdolność do adhezji, inwazji, tworzenia wewnątrzkomórkowych agregatów bakteryjnych i złożonych struktur biofilmu w obrębie skolonizowanych dróg moczowych. Szczepy E. coli Dr+ stanowią trzecią grupę UPECs, które produkują homopolimeryczne struktury adhezyjne, występujące na powierzchni komórek bakteryjnych w postaci fimbrii Dr. Są one odpowiedzialne za zapalenie pęcherza moczowego u dzieci i odmiedniczkowe zapalenie nerek u dorosłych, zwłaszcza u kobiet ciężarnych (40% przypadków, w III trymestrze ciąży). Zdolność do tworzenia biofilmu stanowi również przyczynę przewlekłości tych zakażeń i trudności terapeutyczne. W toku prowadzonych badań wykazano, że fimbrie Dr i białko DraD stanowią główne determinanty urowirulencji klinicznego izolatu E. coli IH11128 Dr+, odpowiedzialne za tworzenie biofilmu, natomiast autoagregująca adhezyna Ag43 może wpływać na jego rozwój i zwiększenie przeżywalności bakterii w komórkach uroepitelialnych. Wstępne analizy wykazały również, że bakterie te wzrastające na podłożu polistyrenowym, tworzą biofilm o rozgałęzionej, drzewiastej strukturze z komórkami uwięzionymi w rozległej macierzy pozakomórkowej. Powyższe dane eksperymentalne wymagają jednak dalszych badań, dotyczących struktury i składu biochemicznego biofilmu, w odniesieniu do aktywności metabolicznej komórek bakteryjnych.

  • Bio-inspired approaches for explosives detection
    • Wasilewski Tomasz
    • Jacek Gębicki
    • Wojciech Kamysz
    2021 Pełny tekst TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    Due to unique abilities of the animals regarding analysis of complex gas substances, they still remain a gold standard in analysis of explosives. Unusual capabilities of biological chemosensory systems, including both vertebrates and invertebrates, stimulate elaboration of the devices mimicking their activity and operation parameters as precisely as possible. The electronic analogues are a subject of investigation in many research centres, which brings their successful commercialization closer. They are believed to substitute or to complement animals in the analysis of gas substances, including explosive and hazardous ones. The limitations of classic gas sensors can be overcome using the strategies inspired by the solutions known from biological systems. Apart from high selectivity and sensitivity desired for analysis of the explosives, mimicking biological systems allows overcoming other problems connected mainly with effective sampling and odour localization. Presented review is focused on the biomimetic devices, which mimic the sense of smell in a direct way and which are the inspiration to design the devices used for detection of the explosives. Potential of biosensors and bioelectronic noses (B-ENs) to mimic the incredibly accurate and versatile "biological noses" was evaluated. A summary of the strategies inspired by biological olfactory systems should facilitate the approach to the problem of artificial instruments design and to development of the strategy aimed at analysis of the explosives with these systems.

  • BIOLOGICAL AGE ASSESSMENT ALGORITHMS BASED ON X-RAY IMAGES OF BONE TISSUE
    • Natalia Głowacka
    2021

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  • Biologically active compounds based on the carbazole scaffold - synthetic and mechanistic aspects
    • Milena Witkowska
    2021 Pełny tekst

    Doctoral dissertation is divided into three main parts: introduction, results and discussion and experimental. The introduction is divided into four main parts which describe: 5-hydroxytryptamine receptors, the most popular antidepressants, new compounds based on the carbazole structure with affinity for serotonin receptors, telomeres and telomerase with their functions, telomerase inhibition strategies, carbazoles approved in cancer treatment, new carbazole derivatives which are telomerase inhibitors and selected methods of synthesis tetrahydrocarbazole and carbazole derivatives. The main part of the work are results and discussion. In this chapter the effects of experiments in the synthesis of 1,2,3,4-tetrahydrocyclopenta[b]indoles, 1,2,4-trisubstituted carbazole derivatives and 1,2,3,6-tetrasubstituted carbazole derivatives are described. The experimental part includes procedures for the preparation of compounds, spectral analysis of products and a list of instruments that were used in the implementation of this work.

  • Biomass in biogas production: Pretreatment and codigestion
    • Archana Kasinath
    • Sylwia Fudala-Książek
    • Małgorzata Szopińska
    • Hubert Byliński
    • Wojciech Artichowicz
    • Anna Remiszewska-Skwarek
    • Aneta Łuczkiewicz
    2021 Pełny tekst RENEWABLE & SUSTAINABLE ENERGY REVIEWS

    Globally, there is increasing awareness that the implementation of ‘waste to energy’ technology is one of the best means to achieve sustainable energy development. The most popular approach is the conversion of organic-rich compounds into clean and renewable products by anaerobic digestion (AD). Biogas can be produced from agricultural residues, municipal/industrial biowastes, and sustainable biomass, especially materials that are locally available. However, in many cases, the methane yields obtained from the conventional AD process are regarded as having limited profitability. This paper summarizes the recent knowledge regarding the different strategies that are used to enhance AD efficiency and the methods to strengthen the existing incentives to overcome today's barriers to biogas production. Special attention was given to several approaches used to improve the biodegradability of organic matter and the methane potential of feedstocks, mainly codigestion and pretreatment of single/mixed substrates. The statistical analyses indicated enormous variability among biogas systems, thus, there is a need for unification of the methods applied for process control and the parameters used for the discussion of results. A synchronized methodology is also needed to understand the environmental advantages and drawbacks of selected utilization pathways in biogas production. Currently, the underestimated potential of AD is of growing interest, and pretreatment/codigestion can directly increase the effectiveness of this technology and lead to its optimization. Nonetheless, a proper evaluation of the environmental (e.g., sustainable biomass) and social (e.g., bioaerosol nuisance) aspects is also needed.

  • Biomass Production and Removal of Nitrogen and Phosphorus from Processed Municipal Wastewater by Salix schwerinii: A Field Trial
    • Muhammad Mohsin
    • Erik Kaipiainen
    • Mir Md Abdus Salam
    • Nikolai Evstishenkov
    • Nicole Nawrot
    • Aki Villa
    • Ewa Wojciechowska
    • Suvi Kuittinen
    • Ari Pappinen
    2021 Pełny tekst Water

    In many Baltic regions, short-rotation willow (Salix spp.) is used as a vegetation filter for wastewater treatment and recycling of valuable nutrients to upsurge bioeconomy development. In this context, a four-year field trial (2016–2019) was carried out near a wastewater treatment plant in eastern Finland (Outokumpu) to investigate the effect of the processed wastewater (WW) on biomass production as well as the nutrients uptake capability (mainly N and P) by a willow variety (Salix schwerinii). Results indicated that WW irrigation expressively increased the willow diameter growth and biomass yield around 256% and 6510%, respectively, compared to the control treatment site (without WW). The willow was also able to accumulate approximately 41–60% of the N and 32–50% of the P in two years (2018–2019). Overall, willow showed a total 20% mortality rate under WW irrigation throughout the growing periods (2017–2019) as compared to control (39%). The results demonstrate that willow has the potential to control eutrophication (reducing nutrients load) from the wastewater with the best survival rate and can provide high biomass production for bioenergy generations in cold climatic conditions.

  • Biomass-Derived Nitrogen Functionalized Carbon Nanodots and Their Anti-Biofouling Properties
    • Maria Rybarczyk
    • Emilia Gontarek-Castro
    • Karolina Ollik
    • Marek Lieder
    2021 Pełny tekst Processes

    The prevalence of the antibiotic resistant bacteria remains a global issue. Cheap, sustainable and multifunctional antibacterial membranes are at the forefront of filtrating materials capable of treating multiple flow streams, such as water cleansing treatments. Carbon nanomaterials are particularly interesting objects shown to enhance antibacterial properties of composite materials. In this article, amino-functionalized, photoluminescent carbon nanodots (CNDs) were synthesized from chitosan by bottom-up approach via simple and green hydrothermal carbonization. A chemical model for the CNDs formation during hydrothermal treatment of chitosan is proposed. The use of urea as an additional nitrogen source leads to the consumption of hydroxyl groups of chitosan and higher nitrogen doping level as pyridinic and pyrrolic N-bonding configurations in the final carbonaceous composition. These functionalized carbon nanodots that consist of carbon core and various surface functional groups were used to modify the commercially available membranes in order to enhance their anti-biofouling properties and add possible functionalities, including fluorescent labelling. Incorporation of CNDs to membranes increased their hydrophilicity, surface charge without compromising membranes integrity, thereby increasing the factors affecting bacterial wall disruption. Membranes modified with CNDs effectively stopped the growth of two Gramnegative bacterial colonies: Klebsiella oxytoca (K. oxytoca) and Pseudomonas aeruginosa (P. aeruginosa).

  • Biomechanics of Lumbar Spine Injury in Road Barrier Collision–Finite Element Study
    • Łukasz Pachocki
    • Karol Daszkiewicz
    • Piotr Łuczkiewicz
    • Wojciech Witkowski
    2021 Pełny tekst Frontiers in Bioengineering and Biotechnology

    Literature and field data from CIREN database have shown that lumbar spine injuries occur during car crashes. There are multiple hypotheses regarding how they occur; however, there is no biomechanical explanation for these injuries during collisions with road safety barriers (RSBs). Therefore, the objective of this study was to investigate the mechanics of vertebral fractures during car collisions with concrete RSBs. The finite element method was used for the numerical simulations. The global model of the car collision with the concrete RSB was created. The lumbar spine kinematics were extracted from the global simulation and then applied as boundary conditions to the detailed lumbar spine model. The results showed that during the collision, the occupant was elevated, and then dropped during the vehicle landing. This resulted in axial compression forces 2.6 kN with flexion bending moments 34.7 and 37.8 Nm in the L2 and L3 vertebrae. It was shown that the bending moment is the result of the longitudinal force on the eccentricity. The lumbar spine index for the L1–L5 section was 2.80, thus indicating a lumbar spine fracture. The minimum principal strain criterion of 7.4% and damage variable indicated L2 and L3 vertebrae and the inferior part of L1, as those potentially prone to fracture. This study found that lumbar spine fractures could occur as a consequence of vehicle landing during a collision with a concrete RSB mostly affecting the L1–L3 lumbar spine section. The fracture was caused by a combination of axial forces and flexion bending moments.

  • Biomechanics of the medial meniscus in the osteoarthritic knee joint
    • Karol Daszkiewicz
    • Piotr Łuczkiewicz
    2021 Pełny tekst PeerJ

    Background. Increased mechanical loading and pathological response of joint tissue to the abnormal mechanical stress can cause degradation of cartilage characteristic of knee osteoarthritis (OA). Despite osteoarthritis is risk factor for the development of meniscal lesions the mechanism of degenerative meniscal lesions is still unclear. Therefore, the aim of the study is to investigate the influence of medial compartment knee OA on the stress state and deformation of the medial meniscus. Methods. The finite element method was used to simulate the stance phase of the gait cycle. An intact knee model was prepared based on magnetic resonance scans of the left knee joint of a healthy volunteer. Degenerative changes in the medial knee OA model were simulated by nonuniform reduction in articular cartilage thickness in specific areas and by a decrease in the material parameters of cartilage and menisci. Two additional models were created to separately evaluate the effect of alterations in articular cartilage geometry and material parameters of the soft tissues on the results. A nonlinear dynamic analysis was performed for standardized knee loads applied to the tibia bone. Results. The maximum von Mises stress of 26.8 MPa was observed in the posterior part of the medial meniscus body in the OA model. The maximal hoop stress for the first peak of total force was 83% greater in the posterior horn and only 11% greater in the anterior horn of the medial meniscus in the OA model than in the intact model. The reduction in cartilage thickness caused an increase of 57% in medial translation of the medial meniscus body. A decrease in the compressive modulus of menisci resulted in a 2.5-fold greater reduction in the meniscal body width compared to the intact model. Conclusions. Higher hoop stress levels on the inner edge of the posterior part of the medial meniscus in the OA model than in the intact model are associated with a greater medial translation of the meniscus body and a greater reduction in its width. The considerable increase in hoop stresses shows that medial knee OA may contribute to the initiation of meniscal radial tears.

  • BIOMEDICAL ENGINEERING EDUCATION IN POLAND - PIONEERS AND INSTITUTIONS
    • Antoni Nowakowski
    2021

    The aim of this chapter is to show the history of biomedical engineering education in Poland, from the beginning till today with special task to underline the role of modern information technology. This story is not very old, just around one century, that may be classified into four basic periods related to important historic events. First are the beginnings before the second world war. Then post-war recovery and development of fundamentals, this is the period from 1946 till around 1970. The third period, till the change of political system in Poland in “nineties”, may be called formation of multicentre knowledge based education. Finally, from ca 1995, development of modern biomedical engineering education supported by “explosion” of information technologies. Each period is here characterised. Many data are given based on personal memory as the author was privileged to know almost all pioneers involved in biomedical engineering education in Poland and participated in many important events/moments of institutions involved in development of modern biomedical engineering.

  • Bistability in a One-Dimensional Model of a Two-Predators-One-Prey Population Dynamics System
    • Sergey Kryzhevich
    • Viktor Avrutin
    • Gunnar Sӧderbacka
    2021 Pełny tekst Lobachevskii Journal of Mathematics

    In this paper, we study a classical two-predators-one-prey model. The classical model described by a system of three ordinary differential equations can be reduced to a one-dimensional bimodalmap. We prove that this map has at most two stable periodic orbits. Besides, we describe the bifurcation structure of the map. Finally, we describe a mechanism that leads to bistable regimes. Taking this mechanism into account, one can easily detect parameter regions where cycles with arbitrary high periods or chaotic attractors with arbitrary high numbers of bands coexist pairwise.

  • Block graphs with large paired domination multisubdivision number
    • Christina M. Mynhardt
    • Joanna Raczek
    2021 Pełny tekst Discussiones Mathematicae Graph Theory

    The paired domination multisubdivision number of a nonempty graph G, denoted by msdpr(G), is the smallest positive integer k such that there exists an edge which must be subdivided k times to increase the paired domination number of G. It is known that msdpr(G) ≤ 4 for all graphs G. We characterize block graphs with msdpr(G) = 4.

  • Blockchain technologies to address smart city and society challenges
    • Julian Szymański
    • Higinio Mora
    • Julio Mendoza-Tello
    • Erick Varela-guzmán
    2021 COMPUTERS IN HUMAN BEHAVIOR

    New Information and Communications Technologies (ICT) are changing the way in which the world works. These technologies provide new tools to face the issues of contemporary society (poverty, migrations, sustainable development challenges, governance, etc.). Among them, blockchain emerge as a disruptive technology able to make things in a completely different and innovative way. They can provide solutions where before there were none. Recently, these technologies have become subject of intense research and development by industry and academia. In consequence, a large amount of interesting works is published in many areas, proposing solutions, services, frameworks and applications based on these technologies. The research focusing on the previous challenges are especially interesting in current society. However, the proposals arrive at higher speed than society can assimilate them, and sometimes they are not properly exploited. Thus, this paper provides a comprehensive overview of the blockchain technology to identify what are its key attributes that enable to successfully address the social challenges. The review has been conducted from three point of views: service-delivery, resource-management and city-administration, and has been focused on the Sustainable Development Goals of the United Nations, in order to cover the full agenda of current social issues. The contributions of this work are an exhaustive compilation of the existing research on blockchain technology to tackle the social challenges from several angles, and the identification of the key features and the conditioning factors of the practical applicability of the technology.

  • Blockchain: zdecentralizowane zaufanie
    • Stanisław Barański
    2021

    Bitcoin wprowadził innowację na wielu płaszczyznach. Jako pierwszy rozwiązał problem osiągania konsensusu w sieciach otwartych, stworzył zagadkę ekonomiczną w postaci globalnej waluty deflacyjnej, pozwolił na transfer pieniędzy tym, którzy wcześniej byli wykluczeni bankowo, ale przede wszystkim stworzył fundamenty pod platformę zdecentralizowanego zaufania. Zapoczątkował technologie zdecentralizowanych aplikacji, które dotychczas nie mogły istnieć bez zaufanej trzeciej strony. W pracy opisana została ta ostatnia płaszczyzna.

  • Błedy realizacji prac remontowych przyczyną uszkodzeń wilgotnościowych zabytkowego budynku sali BHP w Gdańsku
    • Maciej Niedostatkiewicz
    2021 Pełny tekst Builder

    W artykule przedstawiono opis uszkodzeń wilgotnościowych występujących w historycznym budynku sali VBHP w Gdańsku po zakończeniu prac związanych z jego remonem opraz opisano zakres podjętych prac naprawczych

  • Book Review
    • Edward Szczerbicki
    2021 Intelligent Decision Technologies-Netherlands

    Acting over the last three decades as an Editor and Associate Editor for a number of international journals in the general area of cybernetics and AI, as well as a Chair and Co-Chair of numerous conferences in this field, I have had the exciting opportunity to closely witness and to be actively engaged in the stimulating research area of machine learning and its important augmentation with deep learning techniques and technologies. From this extensive personal perspective of an active researcher, I consider the book “Machine Learning Paradigms: Advances in Deep Learning-based Technological Applications” a very important and truly outstanding contribution into the enhancement of our understanding of how deep learning can be applied in real life centred technologies and techniques within a number of important and truly diverse domains. These domains include medical, geospatial, social, economic, and food processing just to mention a few that are covered in this significant book. Its 16 chapters are all well presented, coherent, and well written. The presented applications are innovative and supported by scientifically rigorous research. I find it remarkable that the Editors were able to complete such a comprehensive compendium on deep learning challenges, advances and applications. With no hesitation, I recommend it as a “must read” reference for researchers, practitioners, and higher research degrees students who want to experience truly exciting deep dive into a full-fledged deep learning. Two renowned global class experts in the field edit the book, which for me is always the best indicator of the importance and quality of the content. I would like to finish this brief review expanding a bit further on my personal viewpoint regarding the book. For any active researcher like myself, the most important advantage of the book is the fact that it leaves its reader with a heightened ability to think – in different ways – about developing, evaluating, and implementing deep learning-based techniques and technologies in real life environments.

  • Boron-Doped Diamond/GaN Heterojunction—The Influence of the Low-Temperature Deposition
    • Michał Sobaszek
    • Marcin Gnyba
    • Sławomir Kulesza
    • Mirosław Bramowicz
    • Tomasz Klimczuk
    • Robert Bogdanowicz
    2021 Pełny tekst Materials

    We report a method of growing a boron-doped diamond film by plasma-assisted chemical vapour deposition utilizing a pre-treatment of GaN substrate to give a high density of nucleation. CVD diamond was deposited on GaN substrate grown epitaxially via the molecular-beam epitaxy process. To obtain a continuous diamond film with the presence of well-developed grains, the GaN substrates are exposed to hydrogen plasma prior to deposition. The diamond/GaN heterojunction was deposited in methane ratio, chamber pressure, temperature, and microwave power at 1%, 50 Torr, 500 C, and 1100 W, respectively. Two samples with different doping were prepared 2000 ppm and 7000 [B/C] in the gas phase. SEM and AFM analyses revealed the presence of well-developed grains with an average size of 100 nm. The epitaxial GaN substrate-induced preferential formation of (111)-facetted diamond was revealed by AFM and XRD. After the deposition process, the signal of the GaN substrate is still visible in Raman spectroscopy (showing three main GaN bands located at 565, 640 and 735 cm1) as well as in typical XRD patterns. Analysis of the current–voltage characteristics as a function of temperature yielded activation energy equal to 93.8 meV.

  • Borrelia burgdorferi BmpA-BBK32 and BmpA-BBA64: New Recombinant Chimeric Proteins with Potential Diagnostic Value
    • Weronika Grąźlewska
    • Bartłomiej Ferra
    • Lucyna Holec-Gąsior
    2021 Pełny tekst Pathogens

    Currently, the diagnosis of Lyme disease is based mostly on two-tiered serologic testing. In the new generation of immunoenzymatic assays, antigens comprise whole-cell lysates of members of the Borrelia burgdorferi sensu lato (s.l.) species complex, with the addition of selected recombinant proteins. Due to the high diversity of members of the B. burgdorferi s.l. genospecies and the low degree of conservation among the amino acid sequences of their proteins, serodiagnostic methods currently in use are not sufficient for the correct diagnosis of borreliosis. Two divalent chimeric proteins (BmpA-BBK32 and BmpA-BBA64) were expressed in Escherichia coli. Following purification by one-step metal-affinity chromatography, preparations were obtained containing milligram levels of chimeric protein exhibiting electrophoretic purity in excess of 98%. Reactivity of the new chimeric proteins with specific human IgG antibodies was preliminarily determined by Western blot. For this purpose, 20 negative sera and 20 positive sera was used. The new chimeric proteins were highly reactive with IgG antibodies contained in the serum of patients suffering from borreliosis. Moreover, no immunoreactivity of chimeric proteins was observed with antibodies in the sera of healthy people. These promising results suggest that new chimeric proteins have the potential to discriminate between positive and negative sera.

  • Bortezomib induces methylation changes in neuroblastoma cells that appear to play a significant role in resistance development to this compound
    • Karolina Łuczkowska
    • Katarzyna Ewa Sokołowska
    • Olga Taryma-Leśniak
    • Krzysztof Pastuszak
    • Anna Supernat
    • Jonas Bybjerg-Grauholm
    • Lise Lotte Hansen
    • Edyta Paczkowska
    • Tomasz K. Wojdacz
    • Bogusław Machaliński
    2021 Pełny tekst Scientific Reports

    The anticancer activity of bortezomib (BTZ) has been increasingly studied in a number of indications and promising results for the use of this treatment have been shown in neuroblastoma. As BTZ treatment is usually administered in cycles, the development of resistance and side effects in patients undergoing therapy with BTZ remains a major challenge for the clinical usage of this compound. Common resistance development also means that certain cells are able to survive BTZ treatment and bypass molecular mechanisms that render BTZ anticancer activity. We studied the methylome of neuroblastoma cells that survived BTZ treatment. Our results indicate that BTZ induces pronounced genome wide methylation changes in cells which recovered from the treatment. Functional analyses of identified methylation changes demonstrated they were involved in key cancer pathology pathways. These changes may allow the cells to bypass the primary anticancer activity of BTZ and develop a treatment resistant and proliferative phenotype. To study whether cells surviving BTZ treatment acquire a proliferative phenotype, we repeatedly treated cells which recovered from the first round of BTZ treatment. The repetitive treatment led to induction of the extraordinary proliferative potential of the cells, that increased with subsequent treatments. As we did not observe similar effects in cells that survived treatment with lenalidomide, and non‑treated cells cultured under the same experimental conditions, this phenomenon seems to be BTZ specific. Overall, our results indicate that methylation changes may play major role in the development of BTZ resistance.

  • Bounds on isolated scattering number
    • Marcin Jurkiewicz
    2021

    The isolated scattering number is a parameter that measures the vulnerability of networks. This measure is bounded by formulas de- pending on the independence number. We present new bounds on the isolated scattering number that can be calculated in polynomial time.

  • Bounds on isolated scattering number
    • Marcin Jurkiewicz
    2021 ANZIAM JOURNAL

    The isolated scattering number is a parameter that measures the vulnerability of networks. This measure is bounded by formulas de- pending on the independence number. We present new bounds on the isolated scattering number that can be calculated in polynomial time.