2021 - Repozytorium publikacji - Politechnika Gdańska

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Effective Drug Concentration and Selectivity Depends on Fraction of Primitive Cells
- Jan Lica
- Miłosz Wieczór
- Grzegorz Jan Grabe
- Mateusz Heldt
- Marta Jancz
- Majus Misiak
- Katarzyna Gucwa
- Wioletta Brankiewicz
- Natalia Maciejewska
- Anna Stupak
- Maciej Bagiński
- Krzysztof Rolka
- Andrzej Hellmann
- Andrzej Składanowski
2021 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Poor efficiency of chemotherapeutics in the eradication of Cancer Stem Cells (CSCs) has been driving the search for more active and specific compounds. In this work, we show how cell density-dependent stage culture profiles can be used in drug development workflows to achieve more robust drug activity (IC50 and EC50) results. Using flow cytometry and light microscopy, we characterized the cytological stage profiles of the HL-60-, A-549-, and HEK-293-derived sublines with a focus on their primitive cell content. We then used a range of cytotoxic substances—C-123, bortezomib, idarubicin, C-1305, doxorubicin, DMSO, and ethanol—to highlight typical densityrelated issues accompanying drug activity determination. We also showed that drug EC50 and selectivity indices normalized to primitive cell content are more accurate activity measurements. We tested our approach by calculating the corrected selectivity index of a novel chemotherapeutic candidate, C-123. Overall, our study highlights the usefulness of accounting for primitive cell fractions in the assessment of drug efficiency.
Effective Gap Size Index for Determination of Optimum Separation Distance Preventing Pounding between Buildings during Earthquakes
- Seyed Mohammad Khatami
- Hosein Naderpour
- Alireza Mortezaei
- Seyed Mohammad Nazem Razavi
- Natalia Lasowicz
- Robert Jankowski
2021 Pełny tekst Applied Sciences-Basel
Seismic excitations may lead to collisions between adjacent civil engineering structures causing major damage. In this paper, an effective equation for calculating the gap size index is proposed so as to provide the optimum separation distance preventing structural pounding during different earthquakes. Evaluation of the best prediction of the required separation distance between two adjacent buildings was carried out by using the lumped mass multi-degree-of-freedom models of structures. Special computer program was used to perform dynamic analyses in order to confirm the accuracy of the proposed formula. For this purpose, several different models of buildings with various properties under different earthquake excitations were analyzed. The results of the study clearly show that the proposed formula for the gap size index (based on vibration periods and damping ratios of buildings) is effective and it allows us to calculate the optimum separation between adjacent structures preventing their pounding during different earthquakes.
Effects of Basalt and Carbon Fillers on Fire Hazard, Thermal, and Mechanical Properties of EPDM Rubber Composites
- Przemysław Rybiński
- Bartłomiej Syrek
- Anna Marzec
- Bolesław Szadkowski
- Małgorzata Kuśmierek
- Olusegun D. Samuel
- Milad Amiri
- Ulugbek Zakirovich Mirkhodjaev
2021 Pełny tekst Materials
Due to growing restrictions on the use of halogenated flame retardant compounds, there is great research interest in the development of fillers that do not emit toxic compounds during thermal decomposition. Polymeric composite materials with reduced flammability are increasingly in demand. Here, we demonstrate that unmodified graphene and carbon nanotubes as well as basalt fibers or flakes can act as effective flame retardants in polymer composites. We also investigate the effects of mixtures of these carbon and mineral fillers on the thermal, mechanical, and rheological properties of EPDM rubber composites. The thermal properties of the EPDM vulcanizates were analyzed using the thermogravimetric method. Flammability was determined by pyrolysis combustion flow calorimetry (PCFC) and cone calorimetry.
Effects of biotransport and hydro-meteorological conditions on transport of trace elements in the Scott River (Bellsund, Spitsbergen)
- Sara Lehmann-konera
- Waldemar Kociuba
- Stanisław Chmiel
- Łukasz Franczak
- Żaneta Polkowska
2021 Pełny tekst PeerJ
The shaping of surface water chemistry in the Svalbard Archipelago is strongly dependent on the geology of the catchment and the process of long-range transport of atmospheric pollutants (LRATP). It was found that the dissolved trace elements in the Scott River, which catchment is characterized by a decreasing degree of glaciation, were of the natural origin (i.a. weathering and dissolution of local geological substratum). The exception was Zn originated from LRATP. The paper describe the influence changes in hydro-meteorological conditions and the presence of a seabird colony on the variability in the transport of trace elements within the Scott River catchment. The work assesses long-time fluctuations in the concentration of twenty five trace elements (i.a. Al, Cr, Cu, Pb, Sr, and Zn) from eighty-four surface water samples and their relation to changes in water discharge (Q), precipitation (P), pH, and dissolved organic carbon (DOC) at two river sites (with one being under the influence of the biotransport factor). Based on the results of matrix correlation and cluster analysis it was found that the additional load of DOC from the nesting site of Larus Argentatus in the mouth section of the river drastically changed the hydro-geochemical cycle of Co, Ni, Zn, Ga, Sr, Rb, Ba and U (0.30 < r < 0.51). Furthermore, the results of cluster analysis confirmed that the bird colony’s nesting site was strongly responsible for the presence of U, Rb, Zn, Ni and marine-derived nutrients (e.g. Se and Li). The discharge of glacier meltwater and the alkaline character of water have a negative effect on the dissolution of Li and Mn (−0.31 < r < −0.51), but positively affect the level of Rb and U (r = 0.31 and 0.35, respectively) due to it being washing out a seabird nesting colony in the mouth section of the Scott River. It was observed that the event of rises in air temperature and rain, which results in increased water discharge, caused an intense transport of the trace elements load. Moreover, results of the precipitation sensitivity coefficient factor (CF) proved that precipitation effect the occurrence of Li, Sr and U in the Scott River.
Effects of FSW Tool Plunge Depth on Properties of an Al-Mg-Si Alloy T-Joint: Thermomechanical Modeling and Experimental Evaluation
- Shabbir Memon
- Dariusz Fydrych
- Aintzane Conde Fernandez
- Hamed Aghajani Derazkola
- Hesamoddin Aghajani Derazkola
2021 Pełny tekst Materials
One of the main challenging issues in friction stir welding (FSW) of stiffened structures is maximizing skin and flange mixing. Among the various parameters in FSW that can affect the quality of mixing between skin and flange is tool plunge depth (TPD). In this research, the effects of TPD during FSW of an Al-Mg-Si alloy T-joint are investigated. The computational fluid dynamics (CFD) method can help understand TPD effects on FSW of the T-joint structure. For this reason, the CFD method is employed in the simulation of heat generation, heat distribution, material flow, and defect formation during welding processes at various TPD. CFD is a powerful method that can simulate phenomena during the mixing of flange and skin that are hard to assess experimentally. For the evaluation of FSW joints, macrostructure visualization is carried out. Simulation results showed that at higher TPD, more frictional heat is generated and causes the formation of a bigger stir zone. The temperature distribution is antisymmetric to the welding line, and the concentration of heat on the advancing side (AS) is more than the retreating side (RS). Simulation results from viscosity changes and material velocity study on the stir zone indicated that the possibility of the formation of a tunnel defect on the skin–flange interface at the RS is very high. Material flow and defect formation are very sensitive to TPD. Low TPD creates internal defects with incomplete mixing of skin and flange, and high TPD forms surface flash. Higher TPD increases frictional heat and axial force that diminish the mixing of skin and flange in this joint. The optimum TPD was selected due to the best materials flow and final mechanical properties of joints.
Effects of laser pulse duration in two-photon vision threshold measurements
- Marcin Marzejon
- Maciej Wojtkowski
- Łukasz Kornaszewski
- Katarzyna Komar
2021 Proceedings of SPIE
Pulsed near-infrared (NIR) light sources can be successfully applied for both imaging and functional testing of the human eye, as published recently1. These two groups of applications have different requirements. For imaging applications, the most preferable is invisible scanning beam while efficiently visible stimulating beam is preferable for functional testing applications. The functional testing of human eye using NIR laser beams is possible due to two-photon vision (2PV) phenomenon. 2PV enables perception of pulsed near-infrared laser light as color corresponding to approximately half of the laser wavelength2. This study aims to characterize two-photon vision thresholds for various pulse lengths from a solid- state sub-picosecond laser (λc = 1043.3 nm, Frep = 62.65 MHz), either of 253 fs duration or elongated by Martinez- type stretcher to 2 ps, and fiber-optic picosecond laser (λc = 1028.4 nm, Frep = 19.19 MHz, p = 12.2 ps).
Effects of Surface Pretreatment of Titanium Substrates on Properties of Electrophoretically Deposited Biopolymer Chitosan/Eudragit E 100 Coatings
- Łukasz Pawłowski
- Michał Bartmański
- Aleksandra Mielewczyk-Gryń
- Andrzej Zieliński
2021 Pełny tekst Coatings
The preparation of the metal surface before coating application is fundamental in determining the properties of the coatings, particularly the roughness, adhesion, and corrosion resistance. In this work, chitosan/Eudragit E 100 (chit/EE100) were fabricated by electrophoretic deposition (EPD) and both their microstructure and properties were investigated. The present research is aimed at characterizing the effects of the surface pretreatment of titanium substrate, applied deposition voltage, and time on physical, mechanical, and electrochemical properties of coatings. The coating’s microstructure, topography, thickness, wettability, adhesion, and corrosion behavior were examined. The applied process parameters influenced the morphology of the coatings, which affected their properties. Coatings with the best properties, i.e., uniformity, proper thickness and roughness, hydrophilicity, highest adhesion to the substrate, and corrosion resistance, were obtained after deposition of chit/EE100 coating on nanotubular oxide layers produced by previous electrochemical oxidation.
Efficacious Alkaline Copper Corrosion Inhibition by a Mixed Ligand Copper(II) Complex of 2,2′-Bipyridine and Glycine: Electrochemical and Theoretical Studies
- Mohamed Ibrahim
- Dalia Saleh
- Morad El-Hendawy
- Ahmed Fallatah
- Gaber Mersal
- Rabah Boukherroub
- Joanna Wysocka
- Jacek Ryl
- Mohammed Amin
2021 ChemElectroChem
A mixed ligand copper(II) complex, namely, [Cu(BPy)(Gly)Cl]⋅2H2O (CuC) (BPy=2,2′-bipyridine and Gly=glycine), was synthesized and characterized. The synthesized CuC complex was tested as inhibitor to effectively mitigate the corrosion of copper in alkaline solutions using the linear sweep voltammetry (LSV) and linear polarization resistance (LPR) techniques. For the sake of comparison, such two D.C. electrochemical techniques were also applied to the Cu/OH− interface in the presence of the two studied free ligands, namely, BPy and Gly. The results showed that the three studied compounds acted as mixed-type inhibitors, with CuC being the most efficacious one. The adsorption of the inhibitor is confirmed from X-ray photoelectron spectroscopy (XPS) profiles by the appearance of organic chlorine as well as pyridine and amine nitrogen bonds. Based on XPS data, it was presumed that the corrosion inhibitor stimulates the formation of Cu2CO3(OH)2 species at the electrode surface since, in the case of a corroded reference sample (in absence of inhibitors), its proportion is trivial. The reactivity of the isolated inhibitors was analyzed by computing several quantum chemical parameters based on the density functional theory (DFT). A good correlation was found between these parameters and the anticorrosive performance. Additionally, Monte Carlo simulation studies were applied to find the best configurational space of ligands and their complex on the Cu(111) surface.
Efficiency limit of excitonic photovoltaic cells under phosphor-based white LED illumination
- Grażyna Jarosz
- Małgorzata Franz
- Rafał Marczyński
- Ryszard Signerski
2021 Pełny tekst ORGANIC ELECTRONICS
The limit of energy conversion of excitonic photovoltaic cells working under white light illumination generated by phosphor-based LED is analysed using the modified Giebink approach. Particularly, the impact of the optical energy gap and energy loss associated with the excitons dissociation at the heterojunction interface on power conversion efficiency of the device are discussed. From the results of our study it follows that the optimal optical energy gap value of organic materials equals 1.87–1.91 eV for the cool light and 1.80–1.82 eV for the warm light. The value of maximum power efficiency reaches 50%, if the energy loss related to excitons dissociation at the interface ED/EA is smaller than 0.3 eV and it decreases up to 40%, if the energy loss reaches the value of 0.5 eV. The obtained results reveal the direction of further improvement of efficiency of organic photovoltaic solar cells for indoor applications.
EFFICIENT LINE DETECTION METHOD BASED ON 2D CONVOLUTION FILTER
- Paweł Kowalski
- Piotr Tojza
2021 Pełny tekst Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
The article proposes an efficient line detection method using a 2D convolution filter. The proposed method was compared with the Hough transform, the most popular method of straight lines detection. The developed method is suitable for local detection of straight lines with a slope from -45˚ to 45˚. Also, it can be used for curve detection which shape is approximated with the short straight sections. The new method is characterized by a constant computational cost regardless of the number of set pixels. The convolution is performed using the logical conjunction and sum operations. Moreover, design of the developed filter and the method of filtration allows for parallelization. Due to constant computation cost, the new method is suitable for implementation in the hardware structure of real-time image processing systems.
Efficient Surrogate Modeling and Design Optimization of Compact Integrated On-Chip Inductors Based on Multi-Fidelity EM Simulation Models
- Piotr Kurgan
2021 Pełny tekst Micromachines
High-performance and small-size on-chip inductors play a critical role in contemporary radio-frequency integrated circuits. This work presents a reliable surrogate modeling technique combining low-fidelity EM simulation models, response surface approximations based on kriging interpolation, and space mapping technology. The reported method is useful for the development of broadband and highly accurate data-driven models of integrated inductors within a practical timeframe, especially in terms of the computational expense of training data acquisition. Application of the constructed surrogate model for rapid design optimization of a compact on-chip inductor is demonstrated. The optimized EM-validated design solution can be reached at a low computational cost, which is a considerable improvement over existing approaches. In addition, this work provides a description and illustrates the usefulness of a multi-fidelity design optimization method incorporating EM computational models of graduated complexity and local polynomial approximations managed by an output space mapping optimization framework. As shown by the application example, the final design solution is obtained at the cost of a few high-fidelity EM simulations of a small-size integrated coil. A supplementary description of variable-fidelity EM computational models and a trade-off between model accuracy and its processing time complements the work.
eFRADIR: An Enhanced FRAmework for DIsaster Resilience
- Alija Pasic
- Rita Girao-Silva
- Ferenc Mogyorosi
- Balazs Vass
- Teresa Gomes
- Peter Babarczi
- Peter Revisnyei
- Janos Tapolcai
- Jacek Rak
2021 Pełny tekst IEEE Access
This paper focuses on how to increase the availability of a backbone network with minimal cost. In particular, the new framework focuses on resilience against natural disasters and is an evolution of the FRADIR/FRADIR-II framework. It targets three different directions, namely: network planning, failure modeling, and survivable routing. The steady state network planning is tackled by upgrading a sub-network (a set of links termed the spine) to achieve the targeted availability threshold. A new two-stage approach is proposed: a heuristic algorithm combined with a mixed-integer linear problem to optimize the availability upgrade cost. To tackle the disaster-resilient network planning problem, a new integer linear program is presented for the optimal link intensity tolerance upgrades together with an efficient heuristic scheme to reduce the running time. Failure modeling is improved by considering more realistic disasters. In particular, we focus on earthquakes using the historical data of the epicenters and the moment magnitudes. The joint failure probabilities of the multi-link failures are estimated, and the set of shared risk link groups is defined. The survivable routing aims to improve the network’s connectivity during these shared risk link group failures. Here, a generalized dedicated protection algorithm is used to protect against all the listed failures. Finally, the experimental results demonstrate the benefits of the refined eFRADIR framework in the event of disasters by guaranteeing low disconnection probabilities even during large-scale natural disasters.
Ekspertyza dot. analizy osadów z powierzchni wewnętrznej rurociągu na ssaniu pompy instalacji opóźnionego koksowania
- Łukasz Gaweł
- Kazimierz Darowicki
2021
Zakres ekspertyzy obejmuje analizę osadu na wewnętrznej stronie rurociągu prowadzącego do pompy wysokociśnieniowej 0960-P35, w tym:  Analizę chemiczną osadów z powierzchni wewnętrznej rurociągu wykonanego ze stali niestopowej  Określenie właściwości magnetycznych osadów  Wskazanie mechanizmu tworzenia się osadów  Wskazanie możliwych metod ograniczających ilość tworzących się osadów na powierzchni stali niestopowej omawianego rurociągu
Ekspertyza dotycząca przyczyn pęknięcia rurociągu 8”-096-P1059, zamówienie nr WU/0402/2020/MS
- Kazimierz Darowicki
- Stefan Krakowiak
- Artur Zieliński
- Mateusz Cieślik
- Tadeusz Sonneck
2021
Wykonano badania nieniszczące i niszczących próbek materiału rurociągu wraz z przygotowaniem próbek do badań z materiału rodzimego.
Ekspertyza z oceną przyczyn powstania korozji oraz oceną ryzyka obniżenia trwałości kabli sprężenia zewnętrznego konstrukcji nośnej mostu M-4 w ciągu drogi krajowej nr 90 przez rzekę Wisłę koło Kwidzyna
- Kazimierz Darowicki
- Stefan Krakowiak
- Łukasz Gaweł
- Michał Szociński
- Tadeusz Sonneck
2021
Celem pracy jest uzyskanie informacji pomocnych do podjęcia właściwej decyzji z punktu widzenia Zarządcy obiektu, co do określenia zakresu niezbędnych działań naprawczych na moście M-4 w ciągu drogi krajowej nr 90 przez rzekę Wisłę koło Kwidzyna, spowodowanych wystąpieniem korozji splotów kabli sprężenia zewnętrznego zlokalizowanego wewnątrz dźwigara skrzynkowego ustroju nośnego przedmiotowego mostu.
El empleo en el marco de la transformación digital: Gig Economy vs Open Collaboration ¿dos caras de una misma moneda?
- David Duenas Cid
2021
Tal y como plantea Pérez [43, 44], estamos viviendo los efectos de una revolución tecnológica ligada al desarrollo de las TICs. Los procesos de innovación, describe, se retroalimentan colectivamente, involucrando diferentes actores (productores, proveedores, distribuidores y consumidores) entrelazados en clústeres o redes dinámicas y complejas. Estos procesos colectivos ayudan a desarrollar e implementar tecnologías y magnifican su impacto hasta crear nuevos paradigmas de producción y consumo. En concreto, Pérez defiende que vivimos bajo un paradigma tecno-económico como resultado de un proceso de aprendizaje colectivo que facilita el uso y la asimilación de la tecnología y su impacto en el funcionamiento de la economía. Este proceso incluye también instituciones públicas, quienes, por ejemplo, adaptan progresivamente sus sistemas
Electrical Tree Growth Behavior Under AC and DC High Voltage in Power Cables
- Mohammad AlShaikh Saleh
- Shady S. Refaat
- Marek Olesz
- Haitham Abu-Rub
2021
This work investigates the impact of an applied AC and DC high voltage on the electrical tree behavior in extruded cross-linked polyethylene (XLPE) insulation based on simulation and experimental validation. Extensive partial discharge (PD) testing methods are being implemented for high voltage cables under AC voltage for monitoring their condition. However, these PD testing methods cannot be utilized for power cables under DC voltages. DC voltages is considered in this study because of the rising implementation of HVDC cables worldwide. Therefore, it is of paramount importance to study the PD behavior originating from defects under DC voltages. Hence, classifying and diagnosing the defects taking place becomes crucial. In this paper, a 3D finite element analysis (FEA)-based modeling is considered to study the electrical treeing behavior using an embedded needle electrode in the XLPE insulation. The experiment entails PD tests with different applied high DC voltages (2.5, 5, 10, 11, and 12 kV) to study the impact on the initiation of PDs and ultimately tree growth. PD measurements were also investigated under AC voltages (7.1, 9.9, 11.3, 12.7, 14.1, and 17 kV) to compare them with PD results obtained with the applied DC voltage. The time-resolved partial discharge (TRPD) patterns are acquired for classifying the severity of the defect present in the XLPE insulation.
Electrochemical Evaluation of Sustainable Corrosion Inhibitors via Dynamic Electrochemical Impedance Spectroscopy
- Paweł Ślepski
- Husnu Gerengi
- Gökhan Gece
- Ertugrul Kaya
- Marziya Rizvi
- Michał Szociński
2021
Finding suitable measurement methods for the effective management of electrochemical problems is of paramount importance, particularly for improving efficiency in corrosion protection. The need for accurate measurement techniques specific to nonstationary conditions has long been recognized, and promising approaches have emerged. This chapter introduces dynamic electrochemical impedance spectroscopy as a novel advancement in electrochemistry that can be used efficiently in galvanostatic and potentiostatic modes. The review focuses first on an explanation of the method and second on presenting a comprehensive corpus covering available studies that have applied dynamic electrochemical impedance spectroscopy for the purpose of preventing corrosion phenomena. This chapter defines the merits of this novel approach compared with the conventional electrochemical impedance spectroscopy method.
Electrochemical glucose sensor based on the glucose oxidase entrapped in chitosan immobilized onto laser-processed Au-Ti electrode
- Wiktoria Lipińska
- Katarzyna Siuzdak
- Jakub Karczewski
- Anna Dołęga
- Katarzyna Grochowska
2021 SENSORS AND ACTUATORS B-CHEMICAL
The study on novel electrode material composed of structured titanium foil with embedded Au nanoparticles and modified with chitosan with entrapped glucose oxidase is presented. To confirm the successful immobilization of glucose oxidase FT-IR analysis was performed. The response of electrodes were tested towards glucose in the presence of different interference compounds and biological fluids. The prepared material exhibits excellent performance for glucose detection with a wide linear range, high sensitivity and very low limit of detection.
Electrochemical simulation of metabolic reduction and conjugation reactions of unsymmetrical bisacridine antitumor agents, C-2028 and C-2053
- Agnieszka Potęga
- Szymon Paczkowski
- Ewa Paluszkiewicz
- Zofia Mazerska
2021 Pełny tekst JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
Electrochemistry (EC) coupled with analysis techniques such as liquid chromatography (LC) and mass spectrometry (MS) has been developed as a powerful tool for drug metabolism simulation. The application of EC in metabolic studies is particularly favourable due to the low matrix contribution compared to in vitro or in vivo biological models. In this paper, the EC(/LC)/MS system was applied to simulate phase I metabolism of the representative two unsymmetrical bisacridines (UAs), named C-2028 and C-2053, which contain nitroaromatic group susceptible to reductive transformations. UAs are a novel potent class of antitumor agents of extraordinary structures that may be useful in the treatment of difficult for therapy human solid tumors such as breast, colon, prostate, and pancreatic tumors. It is considered that the biological action of these compounds may be due to the redox properties of the nitroaromatic group. At first, the relevant conditions for the electrochemical conversion and product identification process, including the electrode potential range, electrolyte composition, and working electrode material, were optimized with the application of 1-nitroacridine as a model compound. Electrochemical simulation of C-2028 and C-2053 reductive metabolism resulted in the generation of six and five products, respectively. The formation of hydroxylamine m/z [M+H-14]+, amine m/z [M+H-30]+, and novel N-oxide m/z [M+H-18]+ species from UAs was demonstrated. Furthermore, both studied compounds were shown to be stable, retaining their dimeric forms, during electrochemical experiments. The electrochemical method also indicated the susceptibility of C-2028 to phase II metabolic reactions. The respective glutathione and dithiothreitol adducts of C-2028 were identified as ions at m/z 873 and m/z 720. In conclusion, the electrochemical reductive transformations of antitumor UAs allowed for the synthesis of new reactive intermediate forms permitting the study of their interactions with biologically crucial molecules.