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Search results for: mechanism of azole resistance
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Mechanisms of azole resistance among clinical isolates of Candida glabrata in Poland
PublicationCandida glabrata is currently ranked as the second most frequently isolated aetiological agent of human fungal infections, next only to Candida albicans. In comparison with C. albicans, C. glabrata shows lower susceptibility to azoles, the most common agents used in treatment of fungal infections. Interestingly, the mechanisms of resistance to azole agents in C. albicans have been much better investigated than those in C. glabrata....
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The mechanism of overcoming multidrug resistance (MDR) of fungi by amphotericin B and its derivatives
PublicationPrzeprowadzono badania porównawcze w celu określenia aktywności i cytotoksyczności amfoterycyny B (AmB) i jej pochodnych wobec standardowego szczepu S. cerevisiae i jego transformantów zawierających geny C. albicans kodujące białka oporności wielolekowej (MDR) typu ABC i MFS. Pochodne AmB: amid 3-dimetyloaminopropylowy amfoterycyny B oraz ester metylowy N-metylo-N-D-fruktopiranozylo-amfoterycyny B wykazały efekt fungistatyczny...
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Virulence, antifungal susceptibility and molecular mechanisms of echinocandin resistance among Candida isolates recovered from clinical specimens
PublicationFungi of the genus Candida belong to the natural microflora of healthy individuals. However, they can also be a cause of opportunistic infections especially among patients with an impaired immune system. The first line therapy of Candida infections is based on triazoles. However, in recent years there an increase of azole resistant Candida spp., in particular C. glabrata and C. krusei, has been observed. For this reason, echinocandin...
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The Effect of Posaconazole, Itraconazole and Voriconazole in the Culture Medium on Aspergillus fumigatus Triazole Resistance
PublicationTriazoles are the only compounds used as antibiotics in both medicine and agriculture. The presence of triazoles in the environment can contribute to the acquisition of azole resistance among isolates of Aspergillus fumigatus. The objective of this study was to investigate the effect of A. fumigatus exposure to triazoles on susceptibility to these compounds. Seventeen triazole-resistant and 21 triazole-sensitive A. fumigatus isolates...
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Występowanie oraz charakterystyka molekularna oporności na azole wśród klinicznych i środowiskowych izolatów Aspergillus fumigatus
PublicationCelem badań prowadzonych w ramach niniejszej pracy doktorskiej było sprawdzenie występowania oporności na azole grzybów A. fumigatus pochodzących z Polski oraz jej molekularna charakterystyka. W toku badań utworzono kolekcję 200 izolatów A. fumigatus pochodzących z różnych miejsc Polski. W skład kolekcji wchodziły izolaty kliniczne, środowiskowe i weterynaryjne. Przynależność gatunkową badanych grzybów potwierdzono metodami diagnostyki...
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Detection of Polish clinical Aspergillus fumigatus isolates resistant to triazoles
PublicationWe studied the presence of triazole resistance of 121 Aspergillus fumigatus clinical isolates collected in two Polish cities, Warsaw and Wrocław, to determine if resistance is emerging in our country. We identified five itraconazole resistant isolates (4.13%) carrying the TR34/L98H alteration in Cyp51A gene, four of which were cross-resistant to posaconazole and one to voriconazole. One isolate was intermediate susceptible to itraconazole...
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Pharmaceuticals and other contaminants of emerging concern in Admiralty Bay as a result of untreated wastewater discharge: Status and possible environmental consequences
PublicationConsidering how the impact of human activity in Antarctica is growing, the aim of this study was to conduct the first assessment of pharmaceuticals and personal care products (PPCPs), other emerging contaminants (ECs), and antibiotic resistance genes present in the western shore of the Admiralty Bay region of King George Island. In total, more than 170 substances were evaluated to assess the potential environmental risks they pose...
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Effect of Cyclodextrins on Coupling of o-Ethoxybenzenediazonium Salt with Pyrrole, Imidazole and 2-Methylimidazole
PublicationThe effect of b-cyclodextrin on o-ethoxybenzenediazonium salt coupling with pyrrole, imidazole and 2-methylimidazole has been studied. The differences in the reaction course, the overall yield and products distribution have been analyzed. Experiments without cyclodextrins and selected reactions with a- and c-cyclodextrins have been performed for comparison. The results are discussed in terms of co-conformation of azole molecules...
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WIELOLEKOOPORNE ZAKAŻENIA CANDIDA - PROBLEM XXI WIEKU!
PublicationW ostatnich latach obserwuje się dramatyczny wzrost zakażeń grzybiczych, których przyczyną są grzyby z rodzaju Candida (C). Większość zakażeń wywoływana jest przez C. albicans, C. glabrata, C. krusei, C. parapsilosis i C. tropicalis. Dotychczas najczęściej stosowanymi lekami przeciwko Candida spp były azole, jednakże ze względu na występowanie naturalnej oporności na te antybiotyki (C. glabrata i C. krusei) coraz częściej azole...
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Prognozowanie krzywej osiadania pala wierconego z iniekcją ciśnieniową pod podstawą
PublicationArtykuł jest kontynuacją tematyki autora dotyczącą mechanizmu działania iniekcji ciśnieniowej pod podstawą pala wierconego. W poprzednich publikacjach, autor wykazał, że iniekcja ta w głównej mierze uaktywnia zwiększone opory gruntu wzdłuż pobocznicy pala. Na tej podstawie w niniejszym artykule zaprezentowano procedurę obliczeniową prognozowania krzywą osiadania pala wierconego z iniekcją ciśnieniową pod podstawą. Przedstawiono...
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Stimulated by cyclodextrins high yield synthesis of azocrown analogues comprising pyrrole or imidazole residues
PublicationThe influence of cyclodextrins (CDs) on the formation of azocrown ethers comprising pyrrole, imidazole and substituted imidazole has been studied. Pyrrole, imidazole, 2-methyl-, 4-methyl- and 4-phenylimidazole were coupled with bisdiazonium salts derived from bis-1,5-(2-aminophenoxy)-3-oxapentane or bis-1,8-(2-aminophenoxy)-3,6-dioxaoctane to form macrocyclic compounds with two azo units. The syntheses were performed under standard...
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Essential Oils, Silver Nanoparticles and Propolis as Alternative Agents Against Fluconazole Resistant Candida albicans, Candida glabrata and Candida krusei Clinical Isolates
PublicationDevelopment of effective and safe therapeutic treatment of fungal infections remains one of the major challenge for modern medicine. The aim of presented investigation was to analyze the in vitro antifungal activity of selected essential oils, ethanolic extracts of propolis and silver nanoparticles dropped on TiO2 against azole-resistant C. albicans (n = 20), C. glabrata (n = 14) and C. krusei (n = 10) clinical isolates. Among...
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Optical recognition elements: macrocyclic imidazole chromoionophores entrapped in silica xerogel
PublicationMaterials containing new chromoionophores consisting of crown residue and azole moiety as partsof macrocycles were encapsulated by the sol-gel procedure in silica xerogel matrices and proposed aschemical recognition elements especially for such metal ions as Li+, Cs+ and Cu2+. Action of these recognition elements is in principle based on changes of reflectance. The recognition elements containing 21-membered chromogenic...
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Chromogenic azole diazothiacrown ethers
PublicationZsyntezowane zostały etery koronowe zawierające atomy siarki, dwa ugrupowania azowe oraz fragment pirolu lub imidazolu w makropierścieniu.Zbadana została zdolność zsyntezowanych związków makrocyklicznych pod kątem kompleksowania jonów metali metodą spektrofotometrii UV-vis.Największe zmiany spektralne zaobserwowano pod wpływem jonów ołowiu, miedzi, cynku, niklu, kobaltu oraz srebra.W przypadku jonów metali I i II grupy układu okresowego...
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Metallochromic azole azomacrocyclic reagents
PublicationW artykule opisano syntezę makrocyklicznych azozwiązków zawierających resztę pirolową lub imidazolową. Zbadano zdolność kompleksowania jonów metali w acetonitrylu (spektroskopia UV-Vis). Otrzymane związki przetestowano jako jonofory w membranowych elektrodach jonoselektywnych.
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Metallochromic azocrown ethers incorporating azole residues
PublicationZwiązki o charakterze odczynników metalochromowych są szeroko stosowane w chemii analitycznej. Reagenty te zbudowane są zazwyczaj z grupy fenolowej połączonej z ugrupowaniem azowym. Włączenie takiego podstawnika do związków makrocyklicznych spowodowało utworzenie nowej grupy reagentów o charakterze chromojonoforów. Zsyntezowane zostały nowe makrocykliczne chromojonofory zawierające w makropierścieniu grupę fenolową lub azolową....
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The impact of various azole antifungals on the liquid crystalline ordering in itraconazole
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MECHANIZMY OPORNOŚCI NA AZOLE DROŻDŻAKÓW Z RODZAJU CANDIDA
PublicationOporność na rożne grupy chemoterapeutyków jest w ciągu ostatnich lat coraz większym problemem, zwłaszcza jeśli chodzi o dobór odpowiedniej terapii infekcji grzybiczych. Drożdżaki z rodzaju Candida wykazują oporność przede wszystkim na leki z grupy azoli. Jest to grupa leków najczęściej stosowana ze względu niewielką ilość efektów ubocznych w porównaniu do innych grup chemoterapeutyków: echinokandyn czy polienów charakteryzujących...
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New Peptide Based Fluconazole Conjugates with Expanded Molecular Targets
PublicationInfections of Candida spp. etiology are frequently treated with azole drugs. Among azoles, the most widely used in the clinical scenario remains fluconazole (FLC). Promising results in treatment of dangerous, systemic Candida infections demonstrate the advantages of combined therapies carried out with combinations of at least two different antifungal agents. Here, we report five conjugates composed of covalently linked FLC and...
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The role of glucuronidation in drug resistance
PublicationThe final therapeutic effect of a drug candidate, which is directed to a specific molecular target strongly depends on its absorption, distribution, metabolism and excretion (ADME). The disruption of at least one element of ADME may result in serious drug resistance. In this work we described the role of one element of this resistance: phase II metabolism with UDP-glucuronosyltransferases (UGTs). UGT function is the transformation...
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Accurate rolling resistance Rolling resistance measurements can be influenced by a number of factors
PublicationTire rolling resistance is one of the most difficult-to-measure parameters of the tire/ pavement interface, especially if road measurements are required. First of all, it is necessary to measure a fairly small force in the system that is heavily loaded by other forces and subjected to many adverse effects causing measurement errors. The second problem is related to the fact that tire rolling resistance depends on many factors,...
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Examination of cyp51A and cyp51B expression level of the first Polish azole resistant clinical Aspergillus fumigatus isolate
PublicationAspergillus fumigatus is one of the most prevalent airborne fungal pathogens causing infections worldwide. Most A. fumigatus strains are susceptible to azoles, which are administered as the first line therapeutics. However, during last decade the acquired resistance to triazoles by these species has been described. There is a number of publications concerning the examination of clinical A. fumigatus strains from different countries,...
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Correlation between the number of Pro-Ala repeats in the EmrA homologue of Acinetobacter baumannii and resistance to netilmicin, tobramycin, imipenem and ceftazidime
PublicationAcinetobacter baumannii coccobacilli are dangerous to patients in intensive care units because of their multidrug resistance to antibiotics, developed mainly in the past decade. This study aimed to examine whether there is a significant correlation between the number of Pro-Ala repeats in the CAP01997 protein, the EmrA homologue of A. baumannii, and resistance to antibiotics. A total of 79 multidrug-resistant A. baumannii strains...
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Oporność patogennych drożdżaków z rodzaju Candida na chemoterapeutyki przeciwgrzybowe i nowe sposoby jej przełamywania
PublicationCelem badania było określenie podatności na leki przeciwgrzybowe izolatów Candida od pacjentów z polskich szpitali oraz określenie mechanizmów oporności na nie. Drugim celem było zbadanie aktywności przeciwgrzybowej produktów naturalnych (olejków eterycznych i propolisów pszczelich) i mechanizmów ich działania. Prawie 20% zebranych izolatów wykazało oporność na flukonazol oraz oporność krzyżową na cztery badane azole. Większość...
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A five-year retrospective study shows increasing rates of antimicrobial drug resistance in Cabo Verde for both Staphylococcus aureus and Escherichia coli
PublicationObjectives Data on baseline drug resistance is important in informing future antimicrobial stewardship programs. So far, no data on the antimicrobial drug resistance of clinical isolates was available for the African archipelago of Cabo Verde. Methods We have performed a retrospective analysis over five-years (2013-17) of the antimicrombial drug susceptibility profiles of clinical isolates in the two main hospitals of Cabo Verde....
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Final report on noise and rolling resistance
PublicationWork Package 6 deals with environmental impacts of PERS use, including noise and rolling resistance. This report covers preliminary noise tests performed in the laboratory and at the road test sites. The obtained results indicate that PERS material reduce noise considerably - up to 12 dB in comparison to SMA16 reference surface. Noise reduction properties are especially visible in the case of factory produced PERS slabs supplied...
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Methods of Tire Rolling Resistance Measurements
PublicationTire rolling resistance is one of the factors related to tire/road interaction that has important influence on road vehicles performance. Raising fuel price and increased concern related to the environmental changes result in growing interest in reduction of tire rolling resistance that influences fuel consumption, especially in free-flowing highway traffic with moderate speeds. There are several methods of tire rolling resistance measurements....
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Road texture influence on tyre rolling resistance
PublicationTyre performance, one of the critical factors for vehicle users, is strongly related to theroad surface characteristics, most notably to the pavement texture. Phenomena that occur at the tyre/road interface affect tyre friction (skid resistance), rolling resistance, tyre wear and tyre/road noise. This article deals with relationship between surface texture and rolling resistance of light and heavy vehicle tyres. Mean profile depth...
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Ship Resistance Prediction with Artificial Neural Networks
PublicationThe paper is dedicated to a new method of ship’s resistance prediction using Artificial Neural Network (ANN). In the initial stage selected ships parameters are prepared to be used as a training and validation sets. Next step is to verify several network structures and to determine parameters with the highest influence on the result resistance. Finally, other parameters expected to impact the resistance are proposed. The research utilizes...
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Impact of probability distribution on the uncertainty of resistance measurement
PublicationThe paper presents studies on the influence of probability distributions on the expanded uncertainty of the resistance measurement. Choosing the correct probability distribution is very important to estimate of measurement uncertainty. The paper presents the results of analysis of the resistance measurement uncertainty using the technical method of resistance: 100 G. The analysis of the uncertainty...
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On the durability of the hydraulic satellite motor working mechanism in overload condition
PublicationThe paper presents the newest construction of the hydraulic satellite pump/motor. In this study, the fracture of the hydraulic satellite motor working mechanism is investigated. Factors influencing the durability of satellite working mechanism have been described. The durability of the hydraulic satellite motor working mechanism at a load, corresponding to a pressure of 15 MPa supplied with refined rapeseed oil is very low. Analyses...
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INFLUENCE OF LOAD AND INFLATION PRESSURE ON THE TYRE ROLLING RESISTANCE
PublicationTyre load and inflation pressure are important factors controlling rolling resistance of road vehicles. The article presents results obtained in the Technical University of Gdańsk during laboratory and road measurements of different car tyres rolling on different pavements. The knowledge of rolling resistance characteristics is important for modelling car dynamics as well as fuel consumption. It is also necessary to establish proper...
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INFLUENCE OF TEMPERATURE ON THE TYRE ROLLING RESISTANCE
PublicationTemperature is a very important factor controlling rolling resistance of road vehicle tyres. There are at least three different temperatures that may be considered as important factors controlling thermal conditions of the rolling tyre. The most common measure of the thermal conditions during tyre rolling is ambient air temperature. The other two are: pavement temperature and “tyre” temperature. Tyre temperature is the most difficult...
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Engineering method of tire rolling resistance evaluation
PublicationTire rolling resistance is one of the most difficult tire parameters to measure. The reason is that for modern tires the force of rolling resistance corresponds to 0.5–1% of tire load, thus measurements of very small forces must be performed in a heavily loaded system. This constitutes great problems, especially in road conditions. Laboratory measurements are easier to perform, as the environment may be better controlled, but roadwheel...
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Study of the NO2 sensing mechanism of PEDOT-RGO film using in situ Raman Spectroscopy
PublicationIn this work, the mechanism of the NO2 reaction with PEDOT-RGO composite film has been investigated via in situ Raman spectroscopy. Reduced graphene oxide (RGO), poly(3,4-ethylenedioxytiophene)-reduced graphene oxide (PEDOT-RGO) and poly(3,4-ethylenedioxytiophene)/ClO4− (PEDOT/ClO4−) films were fabricated using an electrodeposition method and used as resistance sensors of gaseous nitrogen dioxide. The experimental results indicate...
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Road texture influence on tire rolling resistance
PublicationTire rolling resistance is one of the most important resistive forces acting on road vehicles. It depends on tire and surface characteristics as well as vehicle operating parameters. This paper deals with the influence of road surface texture on rolling resistance of passenger car tires. Results of road measurements performed on variety of road surfaces are presented.
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Tyre rolling resistance and its influence on fuel consumption
PublicationRolling resistance of tyres is one of the major resistive forces acting on any wheeled vehicle. Unfortunately, it is also one of the forces very difficult to measure. It is estimated that in certain traffic conditions (like for example constant speed driving with slow or moderate speed) so called Rolling Resistance Impact Factor may be as high as 0.3. This means that reduction of rolling resistance by 50% would lead to 15% of energy...
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Decreasing CO2 Emissions By Reducing Tire Rolling Resistance
PublicationThe first motor vehicle was built by Nicolas Cugnot almost 250 years ago and since then there has been a continuous process of motor vehicles’ improvements, as well as development of new road pavements. The fuel crisis of the 70s of the 20th century made it clear to vehicle builders that measures should be taken to reduce vehicle fuel consumption and it contributed to an increased interest in electric vehicles. Although significant...
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Influence of Road Wetness on Tire-Pavement Rolling Resistance
PublicationRolling resistance of tires is one of the most important factors influencing energy consumption of road vehicles, especially on rural roads. For practical reasons, most of rolling resistance measurements are usually performed for dry road conditions. Based on the fact that roads are wet during a considerable time over the year and as part of the projects MIRIAM, ROLRES and ROSANNE, the TUG (Technical University of Gdańsk) in Poland...
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The mechanism of grouting action under the base of bored pile
PublicationThe grouting under the base of bored pile is carried out in order to reduce pile settlement and improve its bearing capacity. The principal aim of grouting is to introduce an initial force between the soil and the pile base. In non-cohesive soil, the grouting can also enlarge the pile base area and therefore improve the base resistance. The example of static load tests on instrumented bored piles installed with and without grouting...
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TEMPERATURE INFLUENCE ON TIRE ROLLING RESISTANCE MEASUREMENTS QUALITY
PublicationGlobal warming makes it necessary to reduce energy consumption, which in the case of motor vehicles, is connected, among other things, with reduction of resistive forces acting on a vehicle during its motion. One of the most important components of those forces is rolling resistance, which is very difficult to measure, especially in road conditions. The article deals with issues related to the influence of the thermal state of...
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ANALYSIS OF THE PUNCHING FAILURE MECHANISM IN WORKING PLATFORMS
PublicationPaper presents an analysis of the shear failure mechanism which occurs from the punching of a working platform layer in relation to its thickness, grain size arrangement and mechanical properties, taking into consideration the interaction with soft subgrade. The study is based on the observations of performance of natural scale structures (Streefkerk) and the results of model investigations numerically represented with the use...
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Elctrochemical oxidation and corrosion resistance of the Ti13Nb13Zr alloy
PublicationThis paper presents the results of oxidation and corrosion tests carried out on titanium alloy Ti13Nb13Zr. The oxide film was prepared by electrochemical environment 2M H3PO4 for 30 min and 1 h, at a constant voltage 40V. The tests of corrosion resistance were performed by potentiostatic method in Ringer's solution at different pH values: 7, 5 and 3. The change in an appearance of surface and the increase in corrosion resistance...
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Analysis of Rolling Resistance of Tires With Run Flat Insert
PublicationRun flat properties are required for tires intended for special applications like military or rescue vehicles. Run-Flat inserts make possible to drive a car or truck, with certain restrictions, also when inflation pressure is very low or non-existing (after tire damage). Rolling resistance of tires rolling the inserts increases considerably in relation to the rolling resistance of properly inflated tires. This paper presents results...
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The Niching Mechanism in the Evolutionary Method of Path Planning
PublicationThis paper presents the concept of the niching mechanism in the evolutionary method of path planning. The problem is considered based on the example of a ship path planning. In this method the diversity of individuals is tested in respect to their physical distance, not the fitness function value. The researches show that such an approach increases effectiveness of solution space exploration, what results in a final solution with...
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Modernization of the Trailer for Tyre/Road Rolling Resistance Measurements
PublicationIn the article the ways of defining tyre rolling resistance are presented. The advantages of the laboratory tests of tyre/road rolling resistance and the advantages and disadvantages of on the road tyre/road rolling resistance tests are described. The description of the special trailer used for tyre/road rolling resistance measurements designed and constructed in the Faculty of Mechanical Engineering at Gdansk University of Technology,...
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Comparison of Tire Rolling Resistance Measuring Methods for Different Surfaces
PublicationThe rolling resistance of car tires is one of the most important parameters characterizing tires today. This resistance has a very significant contribution to the energy consumption of wheeled vehicles. The climate crisis has forced tire and car manufacturers to place great emphasis on the environmental impact of their products. Paradoxically, the development of electric vehicles has led to an even greater importance of rolling...
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Light-Modulated Sunscreen Mechanism in the Retina of the Human Eye
PublicationThe functioning of the human eye in the extreme range of light intensity requires a combination of the high sensitivity of photoreceptors with their photostability. Here, we identify a regulatory mechanism based on dynamic modulation of light absorption by xanthophylls in the retina, realized by reorientation of pigment molecules induced by trans–cis photoisomerization. We explore this photochemically switchable system using chromatographic...
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A simple model of the trap-assisted recombination with the excitonic Auger mechanism
PublicationWe present a simple model of the trap-assisted recombination combined with the excitonic Auger mechanism. It has been shown that only six independent transitions of electrons and holes should be taken into account to describe a combination of the Shockley–Read–Hall (SRH) recombination with this excitonic process. This is in opposition to a well-known model of the SRH mechanism with the free carriers Auger effect via deep states,...
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Cavitation Erosion Resistance Influence of Material Properties
PublicationThe cavitation erosion is the phenomena that causes degradation of fluid flow machinery components due to repetitive implosion of cavitation bubbles adjacent to the solid surface. Cavitation erosion is a complex phenomenon, which includes not only hydrodynamic factors of liquid, but also properties of erodible material e.g. microstructure, hardness or Young modulus. In order to reduce the negative impact of erosion on machine components,...