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Repozytorium publikacji
Politechniki Gdańskiej

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  • Modyfikacja cementu kostnego w celu uzyskania długotrwałej ochrony antybakteryjnej
    • Marcin Wekwejt
    2021

    Niniejsza rozprawa doktorska stanowi przewodnik po jednotematycznym cyklu publikacji, dotyczącym modyfikacji akrylowego cementu kostnego celem uzyskania długotrwałej i efektywnej ochrony antybakteryjnej. W ramach niego przeprowadzono badania eksperymentalne polegające na opracowaniu technologii wytwarzania modyfikowanego cementu kostnego oraz procedury medycznej jego stosowania. Cement kostny był modyfikowany przez zastosowanie trzech typów dodatków w różnych stężeniach: antybakteryjnych (nanocząstek srebra, miedzi lub ich kombinacji), biodegradowalnych (celuloza, chitozan, trójfosforan wapnia, polidioksanon i magnez) oraz bioaktywnych (bioszkło 45S5 i 1393-B3). W badaniach oceniano zależność między składem cementu, zwłaszcza rodzajami i stężeniami dodatków, a jego właściwościami fizyczno-chemicznymi, mechanicznymi oraz biologicznymi. Uzyskane wyniki pozwoliły na dobór optymalnego składu chemicznego cementu kompozytowego, w którym dodatek nanosrebra wynosi 1,5% mas., zaś bioaktywnego szkła 5,0 % mas. W zależności od medycznego przeznaczenia, domieszkowany nanosrebrem cement zawierający bioszkło 45S5 zaleca się do zastosowań jako substytut kości z profilaktyczną osłoną antybakteryjną, natomiast cement wzbogacony bioszkłem 1393-B3 do zastosowań terapeutycznych w celu zwalczenia infekcji. Opracowane cementy pozwalają znacząco eliminować problemy związane ze stosowaniem dotychczasowych cementów w praktyce klinicznej.

  • Molecular basis of essentiality of early critical steps in the lipopolysaccharide biogenesis in Escherichia coli K-12: requirement of MsbA, cardiolipin, LpxL, LpxM and GcvB
    • Patrycja Gorzelak
    • Gracjana Klein-Raina
    • Satish Raina
    2021 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    To identify the physiological factors that limit the growth of Escherichia coli K-12 strains synthesizing minimal lipopolysaccharide (LPS), we describe the first construction of strains devoid of the entire waa locus and concomitantly lacking all three acyltransferases (LpxL/LpxM/LpxP), synthesizing minimal lipid IVA derivatives with a restricted ability to grow at around 21 °C. Suppressors restoring growth up to 37 °C of Δ(gmhD-waaA) identified two independent single-amino-acid substitutions—P50S and R310S—in the LPS flippase MsbA. Interestingly, the cardiolipin synthase-encoding gene clsA was found to be essential for the growth of ΔlpxLMP, ΔlpxL, ΔwaaA, and Δ(gmhD-waaA) bacteria, with a conditional lethal phenotype of Δ(clsA lpxM), which could be overcome by suppressor mutations in MsbA. Suppressor mutations basS A20D or basR G53V, causing a constitutive incorporation of phosphoethanolamine (P-EtN) in the lipid A, could abolish the Ca++ sensitivity of Δ(waaC eptB), thereby compensating for P-EtN absence on the second Kdo. A single-amino-acid OppA S273G substitution is shown to overcome the synthetic lethality of Δ(waaC surA) bacteria, consistent with the chaperone-like function of the OppA oligopeptide-binding protein. Furthermore, overexpression of GcvB sRNA was found to repress the accumulation of LpxC and suppress the lethality of LapAB absence. Thus, this study identifies new and limiting factors in regulating LPS biosynthesis.

  • Molecular Dynamics to Predict Cryo-EM: Capturing Transitions and Short-Lived Conformational States of Biomolecules
    • Łukasz Nierzwicki
    • Giulia Palermo
    2021 Pełny tekst Frontiers in Molecular Biosciences

    Single-particle cryogenic electron microscopy (cryo-EM) has revolutionized the field of the structural biology, providing an access to the atomic resolution structures of large biomolecular complexes in their near-native environment. Today’s cryo-EM maps can frequently reach the atomic-level resolution, while often containing a range of resolutions, with conformationally variable regions obtained at 6 Å or worse. Low resolution density maps obtained for protein flexible domains, as well as the ensemble of coexisting conformational states arising from cryo-EM, poses new challenges and opportunities for Molecular Dynamics (MD) simulations. With the ability to describe the biomolecular dynamics at the atomic level, MD can extend the capabilities of cryo-EM, capturing the conformational variability and predicting biologically relevant short-lived conformational states. Here, we report about the state-of-the-art MD procedures that are currently used to refine, reconstruct and interpret cryo-EM maps. We show the capability of MD to predict short-lived conformational states, finding remarkable confirmation by cryo-EM structures subsequently solved. This has been the case of the CRISPR-Cas9 genome editing machinery, whose catalytically active structure has been predicted through both long-time scale MD and enhanced sampling techniques 2 years earlier than cryo-EM. In summary, this contribution remarks the ability of MD to complement cryo-EM, describing conformational landscapes and relating structural transitions to function, ultimately discerning relevant short-lived conformational states and providing mechanistic knowledge of biological function.

  • Molecular level interpretation of excess infrared spectroscopy
    • Maciej Śmiechowski
    2021 Pełny tekst JOURNAL OF MOLECULAR LIQUIDS

    Infrared (IR) spectroscopy is an invaluable tool in studying intermolecular interactions in solvent mixtures. The deviation of the IR spectrum of a mixture from the spectra of its pure components is a sensitive measure of the non-ideality of solutions and the modulation of intermolecular interactions introduced by mutual influence of the components. Excess IR spectroscopy, based on the established notion of excess thermodynamic functions, provides a well-defined picture of such deviation. On the other hand, the difference spectra method strives to obtain so-called affected spectra by numerically removing the bulk component contribution until the IR spectrum of the spectrally affected component is isolated. Although tremendously useful, excess IR spectroscopy remains poorly studied from a computational point of view. Based on ab initio molecular dynamics (AIMD) simulations, IR spectra of a dimethyl sulfoxide (DMSO)–γ-butyrolactone (GBL) liquid mixture are obtained here from first principles, without resorting to experimental input. Using dipolar decomposition techniques, the excess IR spectrum is further analyzed by rigorously separating the contributions from the modulation of the intra- and intermolecular parts of the spectra of both components and the mutual interaction spectrum. It is found that while the intramolecular part of excess IR spectrum is a good predictor of its overall shape, the intermolecular parts are crucial for elucidation of the band shifts and fine details of the IR spectrum of the mixture. Furthermore, the affected IR spectrum is obtained for both components by applying the spectral similarity method. The exact relationship between the affected and excess IR spectrum is derived and the latter is discovered as the predictor of the band shifts in the affected spectrum. Owing to a reduced cancellation effect of intermolecular contributions, the affected spectrum is a physically justified counterpart of the excess IR spectrum, providing a complementary view of the interactions in the mixture.

  • Molecular mechanism of proton-coupled ligand translocation by the bacterial efflux pump EmrE
    • Jakub Jurasz
    • Maciej Bagiński
    • Jacek Czub
    • Miłosz Wieczór
    2021 Pełny tekst PLoS Computational Biology

    The current surge in bacterial multi-drug resistance (MDR) is one of the largest challenges to public health, threatening to render ineffective many therapies we rely on for treatment of serious infections. Understanding different factors that contribute to MDR is hence crucial from the global “one health” perspective. In this contribution, we focus on the prototypical broad-selectivity proton-coupled antiporter EmrE, one of the smallest known ligand transporters that confers resistance to aromatic cations in a number of clinically relevant species. As an asymmetric homodimer undergoing an “alternating access” protomer-swap conformational change, it serves as a model for the mechanistic understanding of more complex drug transporters. Here, we present a free energy and solvent accessibility analysis that indicates the presence of two complementary ligand translocation pathways that remain operative in a broad range of conditions. Our simulations show a previously undescribed desolvated apo state and anticorrelated accessibility in the ligand-bound state, explaining on a structural level why EmrE does not disrupt the pH gradient through futile proton transfer. By comparing the behavior of a number of model charged and/or aromatic ligands, we also explain the origin of selectivity of EmrE towards a broad class of aromatic cations. Finally, we explore unbiased pathways of ligand entry and exit to identify correlated structural changes implicated in ligand binding and release, as well as characterize key intermediates of occupancy changes.

  • Molecular targets for antifungals in amino acid and protein biosynthetic pathways
    • Aleksandra Kuplińska
    • Kamila Rząd
    2021 Pełny tekst AMINO ACIDS

    Fungi cause death of over 1.5 million people every year, while cutaneous mycoses are among the most common infections in the world. Mycoses vary greatly in severity, there are long-term skin (ringworm), nail or hair infections (tinea capitis), recurrent like vaginal candidiasis or severe, life-threatening systemic, multiorgan infections. In the last few years, increasing importance is attached to the health and economic problems caused by fungal pathogens. There is a growing need for improvement of the availability of antifungal drugs, decreasing their prices and reducing side effects. Searching for novel approaches in this respect, amino acid and protein biosynthesis pathways appear to be competitive. The route that leads from amino acid biosynthesis to protein folding and its activation is rich in enzymes that are descriptive of fungi. Blocking the action of those enzymes often leads to avirulence or growth inhibition. In this review, we want to trace the principal processes of fungi vitality. We present the data of genes encoding enzymes involved in amino acid and protein biosynthesis, potential molecular targets in antifungal chemotherapy, and describe the impact of inhibitors on fungal organisms.

  • Molecular Umbrella as A Nanocarrier for Antifungals
    • Andrzej Skwarecki
    • Dorota Martynow
    • Maria Milewska
    • Sławomir Milewski
    2021 Pełny tekst MOLECULES

    A molecular umbrella composed of two O‐sulfated cholic acid residues was applied for the construction of conjugates with cispentacin, containing a “trimethyl lock” (TML) or o‐dithiobenzylcarbamoyl moiety as a cleavable linker. Three out of five conjugates demonstrated antifungal in vitro activity against C. albicans and C. glabrata but not against C. krusei, with MIC90 values in the 0.22–0.99 mM range and were not hemolytic. Antifungal activity of the most active conjugate 24c, containing the TML–pimelate linker, was comparable to that of intact cispentacin. A structural analogue of 24c, containing the Nap‐NH2 fluorescent probe, was accumulated in Candida cells, and TML‐containing conjugates were cleaved in cell‐free extract of C. albicans cells. These results suggest that a molecular umbrella can be successfully applied as a nanocarrier for the construction of cleavable antifungal conjugates.

  • Molecularly targeted nanoparticles: an emerging tool for evaluation of expression of the receptor for advanced glycation end products in a murine model of peripheral artery disease
    • Marcin Woźniak
    • Christian J. Konopka
    • Agata Płoska
    • Jamila Hendhli
    • Anna Siekierzycka
    • Maciej Banach
    • Rafal Bartoszewski
    • Lawrence W. Dobrucki
    • Leszek Kalinowski
    • Iwona T. Dobrucki
    2021 Pełny tekst CELLULAR AND MOLECULAR BIOLOGY

    Abstract Background: Molecular imaging with molecularly targeted probes is a powerful tool for studying the spatio-temporal interactions between complex biological processes. The pivotal role of the receptor for advanced glycation end products (RAGE) in numerous pathological processes, aroused the demand for RAGE targeted imaging in various diseases. In the study, we evaluated the use of a diagnostic imaging agent for RAGE quantification in an animal model of peripheral artery disease, a multimodal dual-labeled probe targeted at RAGE (MMIA-CML). Methods: PAMAM dendrimer was conjugated with Nε-carboxymethyl-lysine (CML) modified albumin to synthesize the RAGE-targeted probe. A control untargeted agent carried native non-modified human albumin (HSA). Bifunctional p-SCN-Bn-NOTA was used to conjugate the 64Cu radioisotope. Surgical right femoral artery ligation was performed on C57BL/6 male mice. One week after femoral artery ligation, mice were injected with MMIA-CML or MMIA-HSA labeled with 64Cu radioisotope and 60 min later in vivo microPET-CT imaging was performed. Immediately after PET imaging studies, the murine hindlimb muscle tissues were excised and prepared for gene and protein expression analysis, using RT-PCR and Western blot technique respectively. To visualize RAGE expression in excised tissues, microscopic fluorescence imaging was performed using RAGE-specific antibodies and RAGE-targeted and -control MMIA. Results: Animals subjected to PET imaging exhibited greater MMIA-CML uptake in ischemic hindlimbs than non-ischemic hindlimbs. We observed a high correlation between fluorescent signal detection and radioactivity measurement. Significant RAGE gene and protein overexpression were observed in ischemic hindlimbs compared to non-ischemic hindlimbs at one week after surgical ligation. Fluorescence microscopic staining revealed significantly increased uptake of RAGE-targeted nanoparticles in both ischemic and non-ischemic muscle tissues compared to the control probe but at a higher level in ischemic hindlimbs. Ischemic tissue exhibited explicit RAGE dyeing following anti-RAGE antibody and high colocalization with the MMIA-CML targeted at RAGE. Conclusions: The present results indicate increased expression of RAGE in the ischemic hindlimb and enable the use of multimodal nanoparticles in both in vitro and in vivo experimental models, creating the possibility for imaging structural and functional changes with a RAGE-targeted tracer.

  • Molybdenum-uranium-vanadium geochemistry in the lower Paleozoic Alum Shale of Scandinavia: Implications for vanadium exploration
    • Leibo Bian
    • Niels H. Schovsbo
    • Anthony Chappaz
    • Xiaowei Zheng
    • Arne Thorshøj Nielsen
    • Thomas Ulrich
    • Xibo Wang
    • Shifeng Dai
    • Jennifer M. Galloway
    • Aleksandra Małachowska
    • Xuhui Xu
    • Hamed Sanei
    2021 INTERNATIONAL JOURNAL OF COAL GEOLOGY

    This paper investigates the hyper-enrichments of molybdenum (Mo), uranium (U), and vanadium (V) in the lower Paleozoic, Alum Shale of Denmark, Sweden, Norway, and Estonia. Molybdenum and U are mainly associated with organic matter and the highest contents are found in the Furongian part of the Alum Shale. This Furongian hyper-enrichment of Mo and U commenced with the Steptoean Positive Carbon Isotope Excursion (SPICE) event. The temporal distribution of V content increases moderately from the Miaolingian to the Furongian, followed by a significant increase in the Early Ordovician. In addition, the vanadium content generally increases towards the offshore, distal part of the Alum Shale basin. The geochemical affinity of V seems to change from organic matter in the Cambrian to minerals in the Early Ordovician. The hyper-enrichment of V in the Lower Ordovician succession appears to result from upwelling of deep oceanic water. The spatial distribution of V in the Alum Shale indicates that the highest concentrations are located in Scania, southernmost Sweden.

  • Monitoring of Caged Bluefin Tuna Reactions to Ship and Offshore Wind Farm Operational Noises
    • Vicente Puig-Pons
    • Ester Soliveres
    • Isabel Pérez-Arjona
    • Victor Espinosa
    • Pedro Poveda-Martínez
    • Jaime Ramis-Soriano
    • Patricia Ordoñez-Cebrián
    • Marek Moszyński
    • Fernando de la Gándara
    • Manuel Bou-Cabo
    • José L. Cort
    • Eladio Santaella
    2021 Pełny tekst SENSORS

    Underwater noise has been identified as a relevant pollution affecting marine ecosystems in different ways. Despite the numerous studies performed over the last few decades regarding the adverse effect of underwater noise on marine life, a lack of knowledge and methodological procedures still exists, and results are often tentative or qualitative. A monitoring methodology for the behavioral response of bluefin tuna (Thunnus thynnus) when exposed to ship and wind turbine operational noises was implemented and tested in a fixed commercial tuna feeding cage in the Mediterranean sea. Fish behavior was continuously monitored, combining synchronized echosounder and video recording systems. Automatic information extracted from acoustical echograms was used to describe tuna reaction to noise in terms of average depth and vertical dimensions of the school and the indicators of swimming speed and tilt direction. Video recordings allowed us to detect changes in swimming patterns. Different kinds of stimuli were considered during bluefin tuna cage monitoring, such as noise generated by feeding boats, wind farm operational noise, and other synthetic signals projected in the medium using a broadband underwater projector. The monitoring system design was revealed as a successful methodological approach to record and quantify reactions to noise. The obtained results suggested that the observed reactions presented a strong relationship with insonification pressure level and time. Behavioral changes associated with noise are difficult to observe, especially in semi-free conditions; thus, the presented approach offered the opportunity to link anthropogenic activity with possible effects on a given marine species, suggesting the possibility of achieving a more realistic framework to assess the impacts of underwater noise on marine animals.

  • Monitoring Regenerative Heat Exchanger in Steam Power Plant by Making Use of the Recurrent Neural Network
    • Tacjana Niksa-Rynkiewicz
    • Natalia Szewczuk-Krypa
    • Anna Witkowska
    • Krzysztof Cpałka
    • Marcin Zalasiński
    • Andrzej Cader
    2021 Pełny tekst Journal of Artificial Intelligence and Soft Computing Research

    Artificial Intelligence algorithms are being increasingly used in industrial applications. Their important function is to support operation of diagnostic systems. This paper pesents a new approach to the monitoring of a regenerative heat exchanger in a steam power plant, which is based on a specific use of the Recurrent Neural Network (RNN). The proposed approach was tested using real data. This approach can be easily adapted to similar monitoring applications of other industrial dynamic objects.

  • Monitoring the curing process of epoxy adhesive using ultrasound and Lamb wave dispersion curves
    • Erwin Wojtczak
    • Magdalena Rucka
    2021 Pełny tekst MECHANICAL SYSTEMS AND SIGNAL PROCESSING

    Monitoring the stiffness of adhesives is a crucial issue when considering the durability andstrength of adhesive joints. While there are many studies conducted on specimens madeonly from adhesive, the problem of curing of an adhesive film in real joints is moderatelyconsidered. This paper presents the monitoring of stiffening of epoxy adhesive using ultra-sound. Ultrasonic pulse velocity method was firstly applied for monitoring of adhesivespecimens. Then, a new procedure using dispersion relations and scanning laser vibrome-try was proposed for monitoring the curing process of an adhesive joint of steel plates. Bothapproaches gave comparable results showing the increase of the dynamic elastic modulusof adhesive in time. The study presented that the proposed procedure was capable of real-time monitoring the curing process of an adhesive layer in multi-layer systems.

  • Mono- and bimetallic (Pt/Cu) titanium(IV) oxide core–shell photocatalysts with UV/Vis light activity and magnetic separability
    • Zuzanna Bielan
    • Ewa Kowalska
    • Szymon Dudziak
    • Kunlei Wang
    • Bunsho Ohtani
    • Anna Zielińska-Jurek
    2021 Pełny tekst CATALYSIS TODAY

    Titanium(IV) oxide is one of the most widely investigated photocatalysts. However, separation of nano-sized particulate titania might result in profitless technologies for commercial applications. Additionally, bare titania is almost inactive under the Vis range of solar spectrum due to its wide bandgap. Therefore, the present study aims to prepare novel coreinterlayer- shell TiO2 magnetic photocatalysts modified with metal nanoparticles (Pt, Cu), which exhibit both photocatalytic and magnetic properties, making it easily separable within the magnetic field. Accordingly, the core-shell structure of Fe3O4@SiO2/TiO2 was obtained in water/TX100/cyclohexane microemulsion. Platinum and copper were photodeposited on four TiO2 templates and characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), specific surface area (BET) measurement and diffuse reflectance spectroscopy (DR-UV/Vis). Photoactivity was studied in the reaction of phenol, acetic acid, and methanol degradation under UV/Vis irradiation, using both polychromatic and monochromatic irradiation (action spectrum analysis). The core-interlayer-shell structure of Pt and Cu modified magnetic photocatalysts was confirmed using scanning transmission electron microscopy (STEM). Magnetic photocatalysts modified with platinum and copper revealed improved photoactivity both in oxidation and reduction photocatalytic reactions, as compared to unmodified Fe3O4@SiO2/TiO2 photocatalysts. Finally, the correlation between physicochemical properties and photocatalytic activities of Fe3O4@SiO2/TiO2-Pt/Cu photocatalysts was investigated. For the first time, the effect of metals’ loading on the efficiency of phenol degradation and mineralization (TOC removal), and quantum efficiency of reaction in the presence of magnetic photocatalysts were analyzed. It was found that phenol can be efficiently decomposed (ca. 100%) during 60 min of UV/Vis irradiation for the photocatalyst recovered within the magnetic field during three subsequent degradation cycles.

  • MONTE CARLO MODELING OF OPTICAL SENSOR FOR POST-OPERATIVE FREE FLAP MONITORING
    • Ignacy Rogoń
    • Piotr Tojza
    • Edmund Wittbrodt
    • Maciej Łuszczek
    • Jerzy Jankau
    2021

    After a preliminary study of the currently employed methods in vitality monitoring of the tissue flaps (TRAM, DIEP, SIEA), a usefulness of optical techniques is discussed. It seems that one of the most promising in monitoring tissue flaps blood flow is a near infrared spectrometry (NIRS). However, a special design of a measurement sensor has to be developed. First, basing on the literature study an optical “window” is characterized. Then, a Monte Carlo examination of the selected sensors constructions are evaluated. Also, design recommendations for a NIR measurement system are presented.

  • Monument / Las Szpęgawski
    • Joanna Kabrońska
    2021 Pełny tekst Architektura-Murator

    Współczesne monumenty często projektowane są tak, aby angażować uwagę odwiedzających miejsce pamięci nie tylko pod względem wizualnym. Zapraszają one do wejścia w swoją przestrzeń, nawet do dotknięcia powierzchni, a tym samym tworzą bliższe i bogatsze więzi ze zwiedzającymi. Tekst przedstawia Monument Pamięci w Lesie Szpęgawskim autorstwa Katarzyny Ephraim jako współczesne miejsce pamięci.

  • More than just a beer—the potential applications of by-products from beer manufacturing in polymer technology
    • Aleksander Hejna
    2021 Pełny tekst Emergent Materials

    Beer is the most popular alcoholic beverage in the world, and its popularity is continuously growing. Currently, global beer production is estimated at around 2 billion hectoliters. Nevertheless, the increasing production capacity implicates the rising issue of generated by-products—brewers’ spent grain, spent hops, spent yeast, and wastewater. They are generated in massive amounts, so having in mind the current pro-ecological trends, it is crucial to look for their utilization methods. Among the possibilities, particular attention should be drawn to polymer technology. This sector can efficiently use different lignocellulosic materials, which could be applied as fillers for polymer composites or sources of particular chemical compounds. Moreover, due to their chemical composition, brewing industry by-products may be used as functional fillers and additives. They could be introduced to enhance the materials’ resistance to oxidation, microbes, or fungi. These issues should be considered especially important in the case of biodegradable polymers, whose popularity is growing over the last years. This paper summarizes the literature reports related to the composition and potential applications of the brewing industry by-products in polymer technology. Moreover, potential directions of research based on the possibilities offered by the brewing industry by-products are presented.

  • Morphology Regulation Mechanism and Enhancement of Photocatalytic Performance of BiOX (X = Cl, Br, I) via Mannitol-Assisted Synthesis
    • Patrycja Wilczewska
    • Aleksandra Bielicka-giełdoń
    • Karol Szczodrowski
    • Anna Malankowska
    • Jacek Ryl
    • Karol Tabaka
    • Ewa Siedlecka
    2021 Pełny tekst Catalysts

    BiOX (X = Cl, Br, I) photocatalysts with dominant (110) facets were synthesized via a mannitol-assisted solvothermal method. This is the first report on the exposed (110) facets-, size-, and defects-controlled synthesis of BiOX achieved by solvothermal synthesis with mannitol. This polyol alcohol acted simultaneously as a solvent, capping agent, and/or soft template. The mannitol concentration on the new photocatalysts morphology and surface properties was investigated in detail. At the lowest concentration tested, mannitol acted as a structure-directing agent, causing unification of nanoparticles, while at higher concentrations, it functioned as a solvent and soft template. The effect of exposed (110) facet and surface defects (Bi(3−x)+, Bi4+, Bi5+) of BiOX on the photocatalytic activity of nanomaterials under the UV–Vis irradiation were evaluated by oxidation of Rhodamine B (RhB) and 5-fluorouracil (5-FU), an anticancer drug, and by reduction of Cr(VI). Additionally, the influence of crucial factors on the formation of BiOX in the synthesis with mannitol was discussed extensively, and the mechanism of BiOX formation was proposed. These studies presented a new simple method for synthesizing BiOX without any additional surfactants or shape control agents with good photocatalytic activity. The study also provided a better understanding of the effects of solvothermal conditions on the BiOX crystal growth.

  • Morphology, Thermo-Mechanical Properties and Biodegradibility of PCL/PLA Blends Reactively Compatibilized by Different Organic Peroxides
    • Marta Przybysz-Romatowska
    • Mateusz Barczewski
    • Szymon Mania
    • Agnieszka Tercjak
    • Józef Haponiuk
    • Krzysztof Formela
    2021 Pełny tekst Materials

    Reactive blending is a promising approach for the sustainable development of bio-based polymer blends and composites, which currently is gaining more and more attention. In this paper, biodegradable blends based on poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA) were prepared via reactive blending performed in an internal mixer. The PCL and PLA content varied in a ratio of 70/30 and 55/45. Reactive modification of PCL/PLA via liquid organic peroxides (OP) including 0.5 wt.% of tert-butyl cumyl peroxide (BU), 2,5-dimethyl-2,5-di-(tert-butylperoxy)-hexane (HX), and tert-butyl peroxybenzoate (PB) is reported. The materials were characterized by rotational rheometer, atomic force microscopy (AFM), thermogravimetry (TGA), differential scanning calorimetry (DSC), tensile tests and biodegradability tests. It was found that the application of peroxides improves the miscibility between PCL and PLA resulted in enhanced mechanical properties and more uniform morphology. Moreover, it was observed that the biodegradation rate of PCL/PLA blends reactively compatibilized was lower comparing to unmodified samples and strongly dependent on the blend ratio and peroxide structure. The presented results confirmed that reactive blending supported by organic peroxide is a promising approach for tailoring novel biodegradable polymeric systems with controllable biodegradation rates.

  • Możliwości i ryzyka związane z automatyzacją weryfikacji pracy studentów na przykładzie przedmiotu Metrologia
    • Sylwia Babicz-Kiewlicz
    • Dariusz Palmowski
    2021 Pełny tekst

    Przedmiot Metrologia jest wykładany na Wydziale Elektroniki, Telekomunikacji i Informatyki Politechniki Gdańskiej na trzecim semestrze studiów na trzech kierunkach: Elektronika i Telekomunikacja, Inżynieria Biomedyczna oraz Automatyka, Cybernetyka i Robotyka. W trakcie zajęć laboratoryjnych studenci wykonują sześć ćwiczeń, z których dwa są całkowicie oceniane przez program weryfikujący poprawność kolejnych wykonywanych zadań. Publikacja ma na celu przedstawienie zalet i wad oceniania automatycznego. Prezentuje możliwości, jakie niesie za sobą automatyzacja oceniania, jednocześnie wskazując wynikające z tego zagrożenia. Na finalną liczbę punktów możliwych do zdobycia na przedmiocie składają się: test, ocena pracy na zajęciach oraz sprawozdanie z każdego z sześciu ćwiczeń. O ile test oraz sprawozdanie są zawsze oceniane przez prowadzącego, o tyle ocena pracy na zajęciach na dwóch ćwiczeniach jest oceniana automatycznie przez program komputerowy. Co więcej, ocenianie to odbywa się w dwojaki sposób: na jednym ćwiczeniu punkty są przydzielane za poprawne wykonanie zadania, a na drugim ćwiczeniu każdorazowa pomyłka powoduje odjęcie 20% pozostałych możliwych do zdobycia punktów za dane zadanie. Wprowadzenie automatycznego oceniania zwalnia prowadzących z nieustannej kontroli studentów, dzięki czemu może on się skupić na zgłaszanych przez nich problemach. Jednocześnie nakłada na prowadzących obowiązek zapewnienia bezawaryjnego sprzętu. Z jednej strony takie ocenianie zapewnia pełen obiektywizm w postaci bezstronności prowadzącego, ale u studentów wywołuje poczucie ostateczności, co z kolei ich bardzo stresuje. Takich dylematów jest więcej. Autorzy w publikacji podjęli próbę analizy pozytywnych i negatywnych aspektów takiej formy oceny pracy na zajęciach.

  • Możliwości i zasady stosowania hybrydowych urządzeń energochłonnych na przykładzie urządzenia SafeEnd
    • Łukasz Jeliński
    • Kazimierz Jamroz
    • Marcin Budzyński
    • Anna Gobis
    • Dawid Bruski
    • Stanisław Burzyński
    • Grzegorz Bagiński
    2021 Drogownictwo

    Od kilku lat na świecie stosowane są urządzenia energochłonne spełniające rolę poduszki zderzeniowej oraz terminala energochłonnego. Urządzenia te stosowane są do osłony zakończeń barier drogowych oraz osłony obiektów znaj-dujących się w strefie bezpieczeństwa drogi. Przykładem takiego urządzenia jest urządzenie energochłonne U-15a SafeEnd (SE) stosowane od niedawna w Polsce, jednakże niektórzy zarządcy dróg zgłaszają obawy do ich stosowania, jako osłony energochłonnej. Największe zastrzeżenia wśród niektórych zarządzających drogami budziły: brak certyfikatu dla systemu SE, jako poduszki zderzeniowej, zbyt mała wielkość powierzchni czołowej (odblaskowej) sposób połączenia SE z barierami na rozjazdach, wymuszający większe odgięcie drogowych barier ochronnych od krawędzi jezdni, generując w ten sposób ryzyko uderzenia w barierę pod kątem przekraczającym 20 stopni, co może zwiększać ryzyko przerwania bariery i najazdu na przeszkodę. W niniejszym artykule zaprezentowano wyniki badań i analiz funkcjonowania urządzenia SE produkcji firmy Saferoad oraz możliwości i zasady stosowania tych urządzeń, jako hybrydowych urządzeń energochłonnych.

  • Możliwości zamiany elektrycznych przepływomierzy powietrza stosowanych w silnikach spalinowych samochodów
    • Robert Otta
    • Dariusz Świsulski
    • Anna Golijanek-Jędrzejczyk
    2021 Pełny tekst Przegląd Elektrotechniczny

    W artykule przedstawiono podstawowe typy przepływomierzy powietrza, stosowane w silnikach spalinowych samochodów: z klapąspiętrzającą, HLM, HFM, Vortex i MAP. Przedstawiono wyniki badania tych przepływomierzy na specjalnie przygotowanym stanowisku pomiarowym. Przeanalizowano możliwość ich zamiany i zweryfikowano taką możliwość w praktyce.

  • MRAS-Based Switching Linear Feedback Strategy for Sensorless Speed Control of Induction Motor Drives
    • Mohamed Amine Fnaiech
    • Jarosław Guziński
    • Mohamed Trabelsi
    • Abdellah Kouzou
    • Mohamed Benbouzid
    • Krzysztof Łuksza
    2021 Pełny tekst ENERGIES

    This paper presents a newly designed switching linear feedback structure of sliding mode control (SLF-SMC) plugged with an model reference adaptive system (MRAS) based sensorless fieldoriented control (SFOC) for induction motor (IM). Indeed, the performance of the MRAS depends mainly on the operating point and the parametric variation of the IM. Hence, the sliding mode control (SMC) could be considered a good control alternative due to its easy implementation and robustness. Simulation and experimentation results are presented to show the superiority of the proposed SLF-SMC technique in comparison with the classical PI controller under different speed ranges and inertia conditions.

  • MRI-Derived Subcutaneous and Visceral Adipose Tissue Reference Values for Children Aged 6 to Under 18 Years
    • Kacper Marunowski
    • Dominik Świętoń
    • Włodzimierz Bzyl
    • Małgorzata Grzywińska
    • Mariusz Kaszubowski
    • Piotr Bandosz
    • Dmitry Khrichenko
    • Maciej Piskunowicz
    2021 Pełny tekst Frontiers in Nutrition

    The assessment of body composition in pediatric population is essential for proper nutritional support during hospitalization. However, currently available methods have limitations. This study aims to propose a novel approach for nutrition status assessment and introduce magnetic resonance imaging (MRI)-derived subcutaneous and visceral fat normative reference values. A total of 262 healthy subjects aged from 6 to 18 years underwent MRI examinations and anthropometric measurements. MRI images at the second lumbar vertebrae were used by two radiologists to perform the semi-automatic tissue segmentation. Based on obtained adipose tissue surface areas and body mass index (BMI) scores sex-specific standard percentile curves (3rd, 10th, 25th, 50th, 75th, 90th, 97th) and z-scores were constructed using LMS method. Additionally, 85th and 95th centiles of subcutaneous and visceral adipose tissue were proposed as equivalents of overweight and obesity. Bland-Altman plots revealed an excellent intra-observer reproducibility and inter-observer agreement. In conclusion, our findings demonstrate highly reproducible method and suggest that MRI-derived reference values can be implemented in clinical practice.

  • Multi-Aspect Quality Assessment Of Mobile Image Classifiers For Companion Applications In The Publishing Sector
    • Karol Draszawka
    2021

    The paper presents the problem of quality assessment of image classifiers used in mobile phones for complimentary companion applications. The advantages of using this kind of applications have been described and a Narrator on Demand (NoD) functionality has been described as one of the examples, where the application plays an audio file related to a book page that is physically in front of the phone's camera. For such a NoD application, an image classifier is a key component. A thorough quantitative evaluation of the accuracy and robustness of such classifiers was conducted using 18 books of various sorts, 48 test classifiers and 10 testers. We analyzed the impact of the type and condition of the books that define the page classification problem, the position of the mobile device camera in the image acquisition process, the parameters of mobile devices used in tests, and selected options in a training process of classifiers.

  • Multicriteria Decision Analysis and Grouping of Analytical Procedures for Phthalates Determination in Disposable Baby Diapers
    • Magdalena Fabjanowicz
    • Justyna Płotka-Wasylka
    • Marek Tobiszewski
    2021 Pełny tekst MOLECULES

    This study presents the application of one of the tools from the multicriteria decision analysis set (MCDA), the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Selected green analytical chemistry metrics were used to rank analytical procedures for the phthalate determination in disposable baby diapers. Nine analytical procedures were assessed in order to find one that has the lowest environmental impact and the best analytical figures of merit. Nine different criteria, where weighting was based on the experts’ evaluation, were used in the procedures’ assessment. With the use of TOPSIS, an easy and straightforward technique, selection of the most appropriate procedure was made.

  • Multifaceted Analyses of Four Different Prototype Lightweight Photovoltaic Modules of Novel Structure
    • Krzysztof Mik
    • Paweł Zawadzki
    • Jan Tarłowski
    • Marcin Bugaj
    • Piotr Grygiel
    • Sebastian Bykuć
    2021 Pełny tekst ENERGIES

    Dynamic growth of photovoltaic capacity in Poland encourages many entities to invest in photovoltaic systems. However, in the case of buildings with low roof-bearing capacity it can be problematic or even impossible to mount conventional PV modules due to their relatively high weight. Hence, the use of lightweight PV modules is a potential solution. In this paper four different prototype silicon lightweight modules of novel structure manufactured by the Xdisc S.A have been investigated in terms of their electrical and thermal features. The measurements showed that all prototypes have efficiency exceeding 19.5% and power in range of 214 to 242 Wp at standard test conditions. Their area density is about 3.5 kg/m2 which is typical for lightweight modules. In turn, the Power-to-Weight Ratio exceeds 40 W/kg threshold and in one case reaches almost 58 W/kg. Thanks to the measurements, the prototypes could be modelled in PVsyst (PVsyst SA, Satigny, Switzerland). The performed simulations of an example PV system revealed that installations based on prototypes have comparable performance to a conventional installation. Nevertheless, at current prices they are less profitable than the standard system and it shows the need for future cost reductions in the manufacturing process. The proposed materials selection may be the starting point for search of inexpensive substitutes of these materials which still conserve modules high performance. A system based on the prototypes can still prove advantageous when simplicity and promptness outweigh higher initial costs.

  • Multimateriałowe oraz wielokolorowe drukowanie wysokiej jakości części z żywic utwardzanych światłem UV w technologii PolyJet
    • Dawid Zieliński
    2021 Pełny tekst Materiały & Maszyny Technologiczne

    Możliwość budowania multimateriałowych oraz wielokolorowych elementów stanowi ważny trend w rozwoju technologii żywicznych druku 3D. W niniejszym opracowaniu skupiono się na charakterystyce podstawowej metody przetwarzającej ciekłe fotopolimery – technologii PolyJet. Omówiono zasadę jej działania oraz najważniejsze aspekty procesu dotyczące m.in. parametrów drukarki, stosowanych struktur podporowych oraz rodzaju uzyskiwanej powierzchni wydruków. Wskazano ponadto główne grupy przetwarzanych materiałów wraz z charakterystyką ich wybranych właściwości. W końcowej części pracy zaprezentowano kluczowe korzyści oraz ograniczenia związane z wykorzystaniem technologii PolyJet, jak i również szereg praktycznych wskazówek.

  • Multi-objective optimization of the cavitation generation unit structure of an advanced rotational hydrodynamic cavitation reactor
    • Xun Sun
    • Ze Yang
    • Xuesong Wei
    • Yang Tao
    • Grzegorz Boczkaj
    • Joon Yong Yoon
    • Xiaoxu Xuan
    • Songying Chen
    2021 Pełny tekst ULTRASONICS SONOCHEMISTRY

    Hydrodynamic cavitation (HC) has been widely considered a promising technique for industrial-scale process intensifications. The effectiveness of HC is determined by the performance of hydrodynamic cavitation reactors (HCRs). The advanced rotational HCRs (ARHCRs) proposed recently have shown superior performance in various applications, while the research on the structural optimization is still absent. The present study, for the first time, identifies optimal structures of the cavitation generation units of a representative ARHCR by combining genetic algorithm (GA) and computational fluid dynamics, with the objectives of maximizing the total vapor volume, , and minimizing the total torque of the rotor wall, . Four important geometrical factors, namely, diameter (D), interaction distance (s), height (h), and inclination angle (θ), were specified as the design variables. Two high-performance fitness functions for and were established from a central composite design with 25 cases. After performing 10,001 simulations of GA, a Pareto front with 1630 non-dominated points was obtained. The results reveal that the values of s and θ of the Pareto front concentrated on their lower (i.e., 1.5 mm) and upper limits (i.e., 18.75°), respectively, while the values of D and h were scattered in their variation regions. In comparison to the original model, a representative global optimal point increased the by 156% and decreased the by 14%. The corresponding improved mechanism was revealed by analyzing the flow field. The findings of this work can strongly support the fundamental understanding, design, and application of ARHCRs for process intensifications.

  • Multi-objective Tabu-based Differential Evolution for Teleportation of Smart Virtual Machines in Private Computing Clouds
    • Jerzy Balicki
    • Piotr Dryja
    2021

    We propose a multi-objective approach for using differential evolution algorithm with tabu search algorithm as an additional mutation for live migration (teleportation) of virtual machines. This issue is crucial in private computing clouds. Teleportation of virtual machines is supposed to be planned to determine Pareto-optimal solutions for several criteria such as workload of the bottleneck host, communication capacity of the critical node, electric power of hosts, and computer costs. Some numerical results are presented for the experimental cloud based on OpenStack platform for smart city and smart education systems.

  • Multi-Technique Investigation of Grave Robes from 17th and 18th Century Crypts Using Combined Spectroscopic, Spectrometric Techniques, and New-Generation Sequencing
    • Magdalena Śliwka-Kaszyńska
    • Marek Ślebioda
    • Anna Brillowska-Dąbrowska
    • Martyna Mroczyńska
    • Jakub Karczewski
    • Anna Marzec
    • Przemysław Rybiński
    • Anna Drążkowska
    2021 Pełny tekst Materials

    The textile fragments of the funeral clothes found in the 17th and 18th century crypts were subjected to spectroscopic, spectrometric, and microbial investigation. The next-generation sequencing enabled DNA identification of microorganisms at the genus and in five cases to the species level. The soft hydrofluoric acid extraction method was optimized to isolate different classes of dyes from samples that had direct contact with human remains. High-performance liquid chromatography coupled with diode matrix and tandem mass spectrometry detectors with electrospray ionization (HPLC-DAD-ESI-MS/MS) enabled the detection and identification of 34 colourants that are present in historical textiles. Some of them are thus far unknown and uncommon dyes. Indigo, madder, cochineal, turmeric, tannin-producing plant, and young fustic were identified as sources of dyes in textiles. Scanning electron microscopy with energy-dispersive X-ray detector (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR) were used to identify and characterize fibres and mordants in funeral gowns. Of the 23 textile samples tested, 19 were silk while the remaining four were recognized as wool. The presence of iron, aluminium, sodium, and calcium suggests that they were used as mordants. Traces of copper, silica, and magnesium might originate from the contaminants. The large amount of silver indicated the presence of metal wire in one of the dyed silk textiles. SEM images showed that textile fibres were highly degraded.

  • Multiuser Stereoscopic Projection Techniques for CAVE-Type Virtual Reality Systems
    • Jacek Lebiedź
    • Adam Mazikowski
    2021 Pełny tekst IEEE Transactions on Human-Machine Systems

    Despite the development of increasingly popular head mounted displays, CAVE-type systems may still be considered one of the most immersive virtual reality systems with many advantages. However, a serious limitation of most CAVE-type systems is the generation of a three-dimensional (3-D) image from the perspective of only one person. This problem is significant because in some applications, the participants must cooperate with each other in the virtual world. This paper presents the adaptation of a one-user CaveAutomaticVirtual Environment (CAVE) installation in the Immersive 3-D Visualization Lab at the Gda´nsk University of Technology to a two-user stereoscopy system. Simultaneous use of two alternative one-user stereoscopies available in the I3DVL (a technique with spectrum separation—Infitec, and active stereo) and a simple electronic circuit have allowed us to transform the one-user stereoscopy CAVE installation to a two-user stereoscopic system. The experiments performed concentrated on several objective measurable parameters. The calculated crosstalk value was low, approximately 1%, which can be considered negligible and shows the proper operation of the proposed technique. Additionally, initial experiments based on the tested two-user application and related to user comfort in the developed two-user stereoscopy are discussed in this paper. However, this topic still needs further research. The proposed solutions are a cheap alternative to adapt the existing one-user CAVE-type systems which support two projection techniques to a two-user system.

  • Multivariate Assessment of Procedures for Molecularly Imprinted Polymer Synthesis for Pesticides Determination in Environmental and Agricultural Samples
    • Mariusz Marć
    • Marta Bystrzanowska
    • Katarzyna Pokajewicz
    • Marek Tobiszewski
    2021 Pełny tekst Materials

    In the case of quantitative and qualitative analysis of pesticides in environmental and food samples, it is required to perform a sample pre-treatment process. It allows to minimalize the impact of interferences on the final results, as well as increase the recovery rate. Nowadays, apart from routinely employed sample preparation techniques such as solid-phase extraction (SPE) or solid-phase microextraction (SPME), the application of molecularly imprinted polymers (MIPs) is gaining greater popularity. It is mainly related to their physicochemical properties, sorption capacity and selectivity, thermo-mechanical resistance, as well as a wide range of polymerization techniques allowing to obtain the desired type of sorption materials, adequate to a specific type of pesticide. This paper targets to summarize the most popular and innovative strategies since 2010, associated with the MIPs synthesis and analytical procedures for pesticides determination in environmental and food samples. Application of multi-criteria decision analysis (MCDA) allows for visualization of the most beneficial analytical procedures in case of changing the priority of each step of analysis (MIPs synthesis, sample preparation process—pesticides extraction, chromatographic analysis) bearing in mind metrological and environmental issues

  • Multivariate Statistical Approach for Nephrines in Womenwith Obesity
    • Ralitsa Robeva
    • Miroslava Nedyalkova
    • Georgi Kirilov
    • Atanaska Elenkova
    • Sabina Zacharieva
    • Błażej Kudłak
    • Natalia Jatkowska
    • Vasil Simeonov
    2021 Pełny tekst MOLECULES

    Catecholamines are physiological regulators of carbohydrate and lipid metabolism during stress, but their chronic influence on metabolic changes in obese patients is still not clarified. The present study aimed to establish the associations between the catecholamine metabolites and metabolic syndrome (MS) components in obese women as well as to reveal the possible hidden subgroups of patients through hierarchical cluster analysis and principal component analysis. The 24-h urine excretion of metanephrine and normetanephrine was investigated in 150 obese women (54 non diabetic without MS, 70 non-diabetic with MS and 26 with type 2 diabetes). The interrelations between carbohydrate disturbances, metabolic syndrome components and stress response hormones were studied. Exploratory data analysis was used to determine different patterns of similarities among the patients. Normetanephrine concentrations were significantly increased in postmenopausal patients and in women with morbid obesity, type 2 diabetes, and hypertension but not with prediabetes. Both metanephrine and normetanephrine levels were positively associated with glucose concentrations one hour after glucose load irrespectively of the insulin levels. The exploratory data analysis showed different risk subgroups among the investigated obese women. The development of predictive tools that include not only traditional metabolic risk factors, but also markers of stress response systems might help for specific risk estimation in obesity patients.

  • NA STYKU LĄDU I WODY - GDAŃSK
    • Anna Orchowska-Smolińska
    2021 Zawód: Architekt

    Na wyjątkowość zasobu kulturowego dawnej Stoczni Gdańskiej składają się różne wartości i czynniki działające na siebie wzajemnie w sposób synergiczny. Obok treści historycznych, związanych z samym zakładem przemysłowym, znajdują się te dotyczące strajków robotniczych i przemian ustrojowych. Dodatkowo, specyfiką krajobrazu przemysłowego, w rozumieniu zabudowy i zagospodarowania, jest pewna „warstwowość”, a dla obserwatora z zewnątrz czasem niezrozumiałe zagęszczenie i chaotyczność. W rzeczywistości są one wynikiem dostosowywania struktury przestrzennej i modyfikacji ciągów technologicznych do nowych potrzeb. Można zatem powiedzieć, że układ ten rozważnie wpisuje nowe potrzeby eksploatacyjne w zastaną przestrzeń. A co z przyszłością tego terenu? Bliższe poznanie zespołu dysponującego całym wachlarzem zasobów, wartości, atutów i symboliki karze postawić sobie szereg pytań o sposoby dalszego postępowania. Jak poprowadzić proces planowanych na tym terenie inwestycji i jak zarządzać dziedzictwem stoczni, by miejsce to dalej żyło? Czy możliwy jest rozwój tego terenu symbiotycznie powiązany z jego ochroną? Jak uszlachetnić jego dziedzictwo, nie redefiniując cennego przekazu? Czy możliwe jest przekształcenie tego terenu zapewniające jego dostępność i przystępność dla wszystkich? Jak sprawić, by dzielnica ta wciąż mówiła o sobie jako o dawnej stoczni, nie będąc sztucznym tworem dla elit? Na te i wiele innych pytań szukamy wciąż odpowiedzi.

  • Najczęstsze problemy usługowych środowisk wdrożeniowych
    • Andrzej Sobecki
    2021

    Zakres dostępnych obecnie rozwiązań informatycznych umożliwia zna- czące usprawnienie procesu wytwarzania i dostarczania oprogramowania do klienta. Poprawna integracja środowiska wytwórczego pozwala wy- eliminować szereg problemów dotyczących wewnętrznej współpracy ze- społów developerskich. Zmiana architektur aplikacji z monolitycznych na rozproszone heterogeniczne zbiory usług wymaga innego podejścia do wdrażania usług. Dotychczasowe metody wydają się być nieefektywne i mogą istotnie zwiększać koszty operacyjne. Nowe typy narzędzi i bi- bliotek pozwalają wreszcie na pełną automatyzację procesu konfiguracji i wdrażania usług, utrzymywania ich wysokiej dostępności oraz dostar- czają nowe mechanizmy zabezpieczania usług. Są one również dostoso- wane m.in. do wykorzystania chmur obliczeniowych, które oferują znacz- nie większa funkcjonalność niż jedynie zbiór połączonych ze sobą serwe- rów. W rozdziale opisano nowoczesne architektury oprogramowania, ich wymagania względem środowiska wdrożeniowego oraz zaprezentowano przykład takiego środowiska. Przy czym nie jest wymagane posiadanie chmury obliczeniowej, aby skorzystać z przedstawianych mechanizmów.

  • Nanosilver-loaded PMMA bone cement doped with different bioactive glasses – evaluation of cytocompatibility, antibacterial activity, and mechanical properties
    • Marcin Wekwejt
    • Si Chen
    • Beata Kaczmarek
    • Małgorzata Nadolska
    • Krzysztof Łukowicz
    • Anna Pałubicka
    • Anna Michno
    • Anna Maria Osyczka
    • Martin Michalek
    • Andrzej Zieliński
    2021 Pełny tekst Biomaterials Science

    Nanosilver-loaded PMMA bone cement (BC-AgNp) is a novel cement developed as a replacement for conventional cements. Despite favorable properties and antibacterial activity, BC-AgNp still lacks biodegradability and bioactivity. Hence, we investigated the doping with bioactive glasses (BGs) to create a new bioactive BC characterized by time-varying porosity and gradual release of nanosilver. The BC Cemex was used as the base material and modified simultaneously with the AgNp and BGs: melted 45S5 and 13-93B3 glasses with various particles size and sol-gel derived SiO2/CaO microparticles. The effect of BGs addition was examined by microscopic analysis, an assessment of setting parameters, wettability, FTIR and UV-VIS spectroscopy, mechanical testing, hemo- and cytocompatibility and antibacterial efficiency studies. The results show that it is possible to incorporate various BGs into BC-AgNp that lead to different properties depending on the type and size of BGs. The smaller particles of melted BGs showed higher porosity and better antibacterial properties with the moderate deterioration of mechanical properties. The sol-gel derived BGs, however, displayed a tendency for agglomeration and random distribution in BC-AgNp. The BGs with greater solubility more efficiently improves the antibacterial properties of BC-AgNp. Besides, the unreacted MMA monomer release could negatively influence the cellular response. Despite that, the cements doped with different bioactive glasses are suitable for medical applications.

  • Nanotechnologie w implantologii – osiągnięcia i wyzwania
    • Michał Bartmański
    2021

    Aktualnie nanotechnologia jest jedną z najszybciej rozwijających się gałęzi przemysłu, w tym również w zakresie medycyny i implantologii. Osiągnięcia nanotechnologii wykorzystuje się w obrazowaniu, diagnostyce, leczeniu chorób nowotworowych i bólu, lecz również szeroko w obszarze projektowania i wytwarzania implantów, w tym głownie modyfikacji powierzchni materiałów, które mają za zadanie chwilowo lub permanentnie zastąpić funkcję naturalnej tkanki lub narządu. Najczęściej wykorzystywanymi materiałami na implanty długotrwałe są tytan i jego stopy, ze względu na odpowiednie właściwości mechaniczne, chemiczne i wysoką biokompaty-bilność. W zakresie interakcji implantu z tkanką, głównie kostną, to powierzchnia materiału implantowanego odgrywa kluczową rolę. W celu nadania lepszych właściwości powierzchniowych implantu, głównie mecha-nicznych i biologicznych, stosuje się wiele metod modyfikacji powierzchni wykorzystujących osiągnięcia nanotechnologii. Wśród nich między innymi wykorzystywanie metalicznych nanocząstek o udowodnionym działaniu antybakteryjnym w celu nadania implantom właściwości biobójczych w obrębie wszczepu. Innymi metodami pozostają elektrolityczne wytwarzanie nano-rurkowych warstw ditlenku tytanu czy osadzanie powłok o grubościach nanometrycznych, głównie na bazie fosforanów wapnia, lub po prostu osadzanie powłok i wytwarzanie warstw z dodatkiem nanocząstek. W prezentacji przedstawione zostaną główne osiągnięcia w zakresie wyko-rzystania nanotechnologii w implantologii oraz omówione zostaną kwestie wciąż nierozwiązane, a które pozostają wyzwaniem dla naukowców z całego świata.

  • Nanotubular Oxide Layer Formed on Helix Surfaces of Dental Screw Implants
    • Magdalena Jażdżewska
    • Michał Bartmański
    2021 Pełny tekst Coatings

    Surface modification is used to extend the life of implants. To increase the corrosion resistance and improve the biocompatibility of metal implant materials, oxidation of the Ti-13Nb- 13Zr titanium alloy was used. The samples used for the research had the shape of a helix with a metric thread, with their geometry imitating a dental implant. The oxide layer was produced by a standard electrochemical method in an environment of 1M H3PO4 + 0.3% HF for 20 min, at a constant voltage of 30 V. The oxidized samples were analyzed with a scanning electron microscope. Nanotubular oxide layers with internal diameters of 30–80 nm were found. An analysis of the surface topography was performed using an optical microscope, and the Sa parameter was determined for the top of the helix and for the bottom, where a significant difference in value was observed. The presence of the modification layer, visible at the bottom of the helix, was confirmed by analyzing the sample cross-sections using computed tomography. Corrosion tests performed in the artificial saliva solution demonstrated higher corrosion current and less noble corrosion potential due to incomplete surface coverage and pitting. Necessary improved oxidation parameters will be applied in future work.

  • Natural Products Counteracting Cardiotoxicity during Cancer Chemotherapy: The Special Case of Doxorubicin, a Comprehensive Review
    • Izabela Koss-Mikołajczyk
    • Vanja Todorovic
    • Sladjana Sobajic
    • Jamal Mahajna
    • Marko Gerić
    • Josep Tur
    • Agnieszka Bartoszek-Pączkowska
    2021 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    Cardiotoxicity is a frequent undesirable phenomenon observed during oncological treatment that limits the therapeutic dose of antitumor drugs and thus may decrease the effec-­‐‑ tiveness of cancer eradication. Almost all antitumor drugs exhibit toxic properties towards cardiac muscle. One of the underlying causes of cardiotoxicity is stimulation of oxidative stress by chem-­‐‑ otherapy. This suggests that an appropriately designed diet or dietary supplements based on edi-­‐‑ ble plants rich in antioxidants could decrease the toxicity of antitumor drugs and diminish the risk of cardiac failure. This comprehensive review compares the cardioprotective efficacy of edible plant extracts and foodborne phytochemicals whose beneficial activity was demonstrated in vari-­‐‑ ous models in vivo and in vitro. The studies selected for this review concentrated on a frequently applied in cancer therapy anthracycline antibiotic – doxorubicin -­‐‑ as the oxidative stress and car-­‐‑ diotoxicity inducing agent.

  • Nauka w świecie cyfrowym okiem młodego inżyniera - phishing w mediach elektronicznych
    • Dominika Bieńkowska
    • Przemysław Falkowski-Gilski
    2021 Pismo PG

    Phishing to metoda oszustwa, w której przestępca podszywa się pod inną osobę lub instytucję w celu wyłudzenia poufnych danych, zainstalowania szkodliwego oprogramowania bądź też nakłonienia ofiary do wykonania określonych zadań. Jest to przestępstwo wykorzystujące zarówno metody socjotechniczne, jak i sztuczki technologiczne do osiągnięcia zaplanowanego celu. Działania hakerów żerują na nieostrożnych ofiarach, skłaniając je do uwierzenia, że mają do czynienia z zaufanym źródłem.

  • NbIr 2 B 2 and TaIr 2 B 2 – New Low Symmetry Noncentrosymmetric Superconductors with Strong Spin–Orbit Coupling
    • Karolina Górnicka
    • Xin Gui
    • Bartlomiej Wiendlocha
    • Loi T. Nguyen
    • Weiwei Xie
    • Robert J. Cava
    • Tomasz Klimczuk
    2021 ADVANCED FUNCTIONAL MATERIALS

    Superconductivity was first observed more than a century ago, but the search for new superconducting materials remains a challenge. The Cooper pairs in superconductors are ideal embodiments of quantum entanglement. Thus, novel superconductors can be critical for both learning about electronic systems in condensed matter and for possible application in future quantum technologies. Here two previously unreported materials, NbIr2B2 and TaIr2B2, are presented with superconducting transitions at 7.2 and 5.2 K, respectively. They display a unique noncentrosymmetric crystal structure, and for both compounds the magnetic field that destroys the superconductivity at 0 K exceeds one of the fundamental characteristics of conventional superconductors (the “Pauli limit”), suggesting that the superconductivity may be unconventional. Supporting this experimentally based deduction, first-principle calculations show a spinsplit Fermi surface due to the presence of strong spin–orbit coupling. These materials may thus provide an excellent platform for the study of unconventional superconductivity in intermetallic compounds.

  • Network design for surface water quality monitoring in a road construction project using Gamma Test theory
    • Sama Azadi
    • Hamid Amiri
    • Mehrdad Ghorbani Mooselu
    • Helge Liltved
    • Roberto Castro-Muñoz
    • Xun Sun
    • Grzegorz Boczkaj
    2021 Pełny tekst Water Resources and Industry

    Road construction has a negative environmental impact on the surrounding aquatic environment, requiring the continuous monitoring of surface water quality. Here, optimization of the water quality monitoring network (WQMN) is an essential step in supporting the sustainable development of road construction projects. This study introduces Gamma Test theory (GTT) as a practical method for optimizing the WQMN of surface waters during road construction. The water quality index (WQI) was computed in 48 monitoring stations for six monitoring periods from 2017 to 2019; data was acquired from a primary monitoring network over a new highway in southern Norway. Based on the results, it is possible to reduce the number of stations by 23% in comparison with the original empirical network. The proposed method could be useful to design the monitoring networks of projects with limited construction time and budget, as well as projects lacking enough data.

  • Neural Modelling of Steam Turbine Control Stage
    • Jerzy Głuch
    • Marta Drosińska-Komor
    2021

    The paper describes possibility of steam turbine control stage neural model creation. It is of great importance because wider application of green energy causes severe conditions for control of energy generation systems operation Results of chosen steam turbine of 200 MW power measurements are applied as an example showing way of neural model creation. They serve as training and testing data of such neural model. Relatively simple set of nozzle boxes neural models consisting control stage is applied. They act as a neural regresor. Research study on ways of creation mentioned neural model is the main purpose of the paper. Finally accurate neural tool is created. It can serve as a proper pattern of control stage operation for engineers tuning turbine control equipment. Another way of application consists in usage as a component of turbomachinery heat and flow diagnostic programs. These programs take mainly into account of technical objects efficiency degradation.

  • Neural Oscillation During Mental Imagery in Sport: An Olympic Sailor Case Study
    • Dagmara Budnik-Przybylska
    • Adrian Kastrau
    • Patryk Jasik
    • Maria Każmierczak
    • Łukasz Doliński
    • Paweł Syty
    • Marta Łabuda
    • Jacek Przybylski
    • Selenia di Fronso
    • Maurizio Bertollo
    2021 Pełny tekst Frontiers in Human Neuroscience

    The purpose of the current study was to examine the cortical correlates of imagery depending on instructional modality (guided vs. self-produced) using various sports-related scripts. According to the expert-performance approach, we took an idiosyncratic perspective analyzing the mental imagery of an experienced two-time Olympic athlete to verify whether different instructional modalities of imagery (i.e., guided vs. self-produced) and different scripts (e.g., training or competition environment) could differently involve brain activity. The subject listened to each previously recorded script taken from two existing questionnaires concerning imagery ability in sport and then was asked to imagine the scene for a minute. During the task, brain waves were monitored using EEG (32-channel g. Nautilus). Our findings indicate that guided imagery might induce higher high alpha and SMR (usually associated with selective attention), whereas self-produced imagery might facilitate higher low alpha (associated with global resting state and relaxation). Results are discussed in light of the neural efficiency hypothesis as a marker of optimal performance and transient hypofrontality as a marker of flow state. Practical mental training recommendations are presented.

  • Neurochemical changes underlying cognitive impairment in olfactory bulbectomized rats and the impact of the mGlu5-positive allosteric modulator CDPPB
    • Agata Płoska
    • Paulina Cieślik
    • Anna Siekierzycka
    • Leszek Kalinowski
    • Joanna M. Wierońska
    2021 BRAIN RESEARCH

    The olfactory bulbectomized (OBX) rat model is a well-established model of depression in which antidepressant drugs reverse deficits in the passive avoidance test 14 days after administration. Recently, the olfactory bulbectomized rat model has been proposed to be a model of Alzheimer’s disease (AD), and the available data indicate similarities between the changes that typically occur in AD and those observed in OBX animals. In the present study, the occurrence of neurochemical impairments related to AD were investigated 8 months after OB ablation. The expression of the nitric oxide synthases eNOS and nNOS, receptor for advanced glycation endproducts (RAGEs) and dimethylarginine dimethylaminohydrolase (DDAH1) in the prefrontal cortices (PFCs), hippocampi and striata of olfactory bulbectomized and sham-operated rats was evaluated. Subsequently, the impact of the administration of a positive allosteric modulator of the mGlu5 receptor, CDPPB (14 days, 2.5 or 5 mg/kg), on OBX-related changes was assessed. OB ablation induced typical deficits in passive avoidance. Significant aberrations in the expression of both isoforms of NOS were observed in the hippocampus and striatum, and the expression of DDAH1 was increased in the PFCs of OBX animals. CDPPB at a dose of 5 mg/kg ameliorated cognitive impairment in the passive avoidance test and partially reversed the changes in eNOS and nNOS expression induced by the lesion. The results of this study confirm that some of the neurochemical changes observed in OBX animals may resemble those associated with AD pathology and that activation of the mGlu5 receptor may partially counteract these pathological alterations.

  • Neuronowe modele z atencją w przetwarzaniu języka naturalnego
    • Szymon Olewniczak
    2021

    Celem niniejszego rozdziału jest wprowadzenie w tematykę sieci neuronowych z atencją oraz ich zastosowań w przetwarzaniu języka naturalnego. Rozdział skupia się w szczególności na dokładnym omówieniu architektury modelu Transformer, wykorzystującego atencję jako podstawowy mechanizm swojego działania.

  • Neurotrophic factors in human milk in early lactation and the effect of Holder and microwave pasteurization on their concentrations
    • Dorota Martysiak-Żurowska
    • Małgorzata Puta
    • Bogumiła Kiełbratowska
    • Aleksandra Wesołowska
    2021 JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION

    Objective: The objective of this study was to determine the level of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) in human milk in the first two weeks of breastfeeding and compare of the effects of Holder pasteurization (HoP, 62.5°C, 30 minutes) and microwave pasteurization (MP) at constant temperature (62.5°C) on the concentraion of both neurotrophic factors (NFs). Methods: Concentration of NFs in human milk was determined using a commercially available ELISA assay. Results: The average concentration of BDNF and GDNF in milk was 11±6 ng/mL and 336 ±238 pg/mL respectively. There was a positive correlation between the concentrations of BDNF and GDNF in human milk and day of lactation (r=0.441, p<0.05 and r=0.482, p<0.05 respectively). In addition, there was a significant correlation between the levels of BDNF and GDNF (r=0.366, p<0.05). HoP and MP for 10 minutes affected both NF levels similarly, causing degradation of BDNF by about 24% and 17%, and GDNF by 47% and 45% respectively. Use of MP for 5 minutes resulted in preservation of nearly 91% BDNF and 79% GDNF in human milk. Conclusions: In the pasteurization processes carried out, results showed that GDNF is more susceptible to degradation under the influence of high temperature. To the authors’ best knowledge, this is the first study evaluating the effects of HoP and MP at constant temperature on the concentration of NFs in human milk. It was found that the MP for 5 minutes is the optimal method.

  • Neutralising Responsibility: A Critical Analysis of an Airline’s Climate Disclosures
    • Eljas Johansson
    2021 Pełny tekst

    Sustainability reporting provides companies with a medium through which they can communicate their non-financial impacts to stakeholders. The airline industry has been much at the centre of the climate change debate in recent years, which is why it is hardly surprising that airlines seek to take a proactive stance in such reporting. This study critically assesses how an airline based in the Scandinavian region constructs sustainability discourse in relation to climate impact in its corporate reporting to stakeholders. The paper uniquely approaches this question by drawing upon thematic analysis combined with an examination of the text’s grammatical meanings. Overall, the findings demonstrate that the company’s climate discourse is characterised by optimistic forward-looking statements and justifications, realised by techniques of neutralisation, whose purpose is to rationalise and legitimise the company’s adverse climate impact. This short paper contributes to the still relatively underexamined research area of airline sustainability reporting by concentrating on the climate disclosures and responding to the lack of latent analysis in this context. This paper’s findings are intended to stimulate the discussion amongst academics and practitioners on how sustainability is communicated in corporate annual reporting to make it more meaningful.

  • New Carvone-Based Deep Eutectic Solvents for Siloxanes Capture from Biogas
    • Patrycja Makoś-Chełstowska
    • Edyta Słupek
    • Aleksandra Kramarz
    • Jacek Gębicki
    2021 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

    During biogas combustion, siloxanes form deposits of SiO2 on engine components, thus shortening the lifespan of the installation. Therefore, the development of new methods for the purification of biogas is receiving increasing attention. One of the most effective methods is physical absorption with the use of appropriate solvents. According to the principles of green engineering, solvents should be biodegradable, non-toxic, and have a high absorption capacity. Deep eutectic solvents (DES) possess such characteristics. In the literature, due to the very large number of DES combinations, conductor-like screening models for real solvents (COSMO-RS), based on the comparison of siloxane activity coefficient of 90 DESs of various types, were studied. DESs, which have the highest affinity to siloxanes, were synthesized. The most important physicochemical properties of DESs were carefully studied. In order to explain of the mechanism of DES formation, and the interaction between DES and siloxanes, the theoretical studies based on σ-profiles, and experimental studies including the 1H NMR, 13C NMR, and FT-IR spectra, were applied. The obtained results indicated that the new DESs, which were composed of carvone and carboxylic acids, were characterized by the highest affinity to siloxanes. It was shown that the hydrogen bonds between the active ketone group (=O) and the carboxyl group (-COOH) determined the formation of stable DESs with a melting point much lower than those of the individual components. On the other hand, non-bonded interactions mainly determined the effective capture of siloxanes with DES.

  • NEW DESIGNS OF MAGNETIC FLUID SEALS FOR RECIPROCATING MOTION
    • Leszek Matuszewski
    • Piotr Bela
    2021 Pełny tekst Polish Maritime Research

    T he operating conditions of magnetic fluid seals during reciprocating motion are so different from those observed in rotating motion that the use of their conventional structures for reciprocating motion seals yields no good results. The analysis of the sealing mechanism of magnetic fluid seals in reciprocating motion shows that the operation of these seals is affected by the carry-over phenomenon and magnetic fluid film deformation in the sealing gap, which depends on the velocity of the reciprocating motion. The reduced amount of magnetic fluid in the sealing gap caused by the reciprocating motion of the shaft is the main reason for seal failures. T he paper presents a short characterisation of magnetic fluid sealing technology, the principle of sealing, the operation of the magnetic fluid and the seal failure mechanism in linear motion of the shaft. Moreover, some new structural designs of hybrid seals, being combinations of typical hydraulic seals with magnetic fluid seals for reciprocating motion, and some examples of magnetic fluid sealing structures for hydraulic cylinders and piston compressors which have practical application values are presented.