2021 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2021

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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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text 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 Full text
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 Full text 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.