Search results for: antibiotic-resistant%20bacteria
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Bee Products and Essential Oils as Alternative Agents for Treatment of Infections Caused by S. aureus
PublicationBacteria of the genus Staphylococcus are important human and veterinary pathogens. A crucial characteristic for this group of bacteria is that they can easily acquire mechanisms of antibiotic resistance for a plethora of antibiotics currently in use for human and animal therapies. Therefore, there is a great need to find novel, non-antibiotic chemotherapeutics with marked antistaphylococcal activity. Promising but still underestimated...
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Influence of a lipid bilayer on the conformational behavior of amphotericin B derivatives - A molecular dynamics study.
PublicationAmphotericin B (AmB) is an effective but very toxic antifungal antibiotic. In our laboratory a series of AmB derivatives of improved selectivity of action was synthesized and tested. To understand molecular basis of this improvement, comparative conformational studies of amphotericin B and its two more selectivederivatives were carried out in an aqueous solution and in a lipid membrane. These molecular simulation studies revealed...
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Stereostructure of mycoheptin A2
PublicationThe absolute configurations of all the stereogenic centers of the antibiotic mycoheptin A2 were established upon previouslyelaborated general procedure, consisting of DQF-COSY, NOESY, ROESY, HSQC and HMBC experiments as major tools. Thestructure of mycoheptin A2 without stereochemistry of its aglycone has been reported before.
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Determination of amikacin and ciprofloxacin by liquid chromatography with pre-column derivatization to evaluate sustained delivery of antibiotics from Drug-Eluting Biopsy Needle
PublicationDetermination of chosen antibacterial antibiotics: amikacin and ciprofloxacin was carried out by HPLC-UV after derivatization with 9-fluorenylmethyl chloroformate and in their native form by HPLC-MS/MS. Developed methods have been applied to control the kinetics of antibiotic release from polymer-based controlled drug delivery system.
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Stereostructure of mycoheptin A2
PublicationThe absolute configurations of all the stereogenic centers of the antibiotic mycoheptin A2 were established upon previously elaborated general procedure, consisting of DQF-COSY, NOESY, ROESY, HSQC and HMBC experiments as major tools. The structure of mycoheptin A2 without stereochemistry of its aglycone has been reported before.
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Amphotericin B and Its New Derivatives - Mode of Action
PublicationAmphotericin B (AmB) is a well known antifungal and antiprotozoal antibiotic used in the clinic for several decades. Clinicalapplications of AmB, however, are limited by its nephrotoxicity and many other acute side effects which are not acceptable by patientswhen their life is not threaten. In order to improve the therapeutic index of this drug, lipid formulations have been introduced and manyefforts have been made to obtain less...
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A new assay for simultaneous identification and differentiation of Klebsiella oxytoca strains
PublicationBacterial strain typing, or identifying bacteria at the strain level, is particularly important for diagnosis, treatment, and epidemiological surveillance of bacterial infections. This is especially the case for bacteria exhibiting high levels of antibiotic resistance or virulence, and those involved in nosocomial or pandemic infections. Strain typing also has applications in studying bacterial population dynamics.
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Activity of isavuconazole and other triazole derivatives against clinical isolates of Aspergillus fumigatus
PublicationAspergillus fumigatus is the most frequent pathogen of the genus Asperillus, which is highly susceptible to triazole derivatives, especially to isavuconazole and voriconazole. Many countries face a growing problem of infections due to A. fumigatus showing acquired resistance to one or several triazoles. In medical centres, monitoring the susceptibility of isolated Aspergillus spp. is recommended. The aim of this study was to collect...
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Mechanical characteristics of welded joints between different stainless steels grades
Publicationnvestigation of mechanical characteristics of welded joints is one of the most important tasks that allow determining their functional properties. Due to the very high, still rising, cost of some stainless steels it is justified, on economic grounds, welding austenitic stainless steel with steels that are corrosion-resistant like duplex ones. According to forecasts the price of...
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Resistance of Escherichia coli and Enterococcus spp. to selected antimicrobial agents present in municipal
PublicationIn this study, the susceptibility to erythromycin (E) and to trimethoprim/sulfamethoxazole (SXT) among isolates of Enterococcus spp. and Escherichia coli was tested, respectively. Both fecal indicators were detected and isolated from raw(RW) and treated wastewater (TW) as well as from samples of activated sludge (AS) collected in a local wastewater treatment plant (WWTP). Biodiversity of bacterial community in AS was also monitored...
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Composite GFRP U-shaped footbridge
PublicationThe paper presents proposals for the use of glass fiber reinforced polymer composites for the construction of engineering objects, known and commonly used in the shipbuilding industry. An example of a pedestrian footbridge was used in this case, which, despite the considerable thickness of the structural material, was made using infusion technology in one production cycle. The designed and produced footbridge span is durable, dynamically...
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Relation of the polymorphism of cyp51A sequence and the susceptibility of Aspergillus fumigatus isolates to triazoles determined by commercial gradient test (Etest) and by reference methods
PublicationThe aim of this study was to evaluate the accuracy of commercial gradient test (Etest) in the detection of triazole resistant Aspergillus fumigatus isolates using reference microdilution methods and the analysis of sequences of the cyp 51A gene. The study was performed on twenty clinical isolates which were identified as Aspergillus fumigatus based on the DNA sequences of the ITS1-2 fragment of ribosomal DNA and the β-tubulin gene,...
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Heptaene macrolides biosynthesis by Streptomyces species
PublicationPolyene macrolides are one of the groups of secondary metabolites, generated by microorganisms belonging to the Streptomyces genus. These compounds, containing 3 - 7 conjugated double bonds systems in their molecules exhibit high antifungal activity against a broad spectrum of fungal pathogens with heptaenes demonstrating the highest antifungal potential. At the large extent, efficiency of biosynthesis of these natural products...
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Ocena odporności na pękanie podbudów drogowych z mieszanek mineralno-cementowo-emulsyjnych (MCE)
PublicationPodbudowy z mieszanek mineralno-cementowo-emulsyjnych (MCE) są jednym z wielu materiałów stosowanych do wykonywania warstw nawierzchni w ramach przebudów dróg w Polsce. Mieszanki MCE pozwalają na maksymalne powtórne wykorzystanie istniejących warstw konstrukcyjnych do budowy lub przebudowy nawierzchni. Do wykonania podbudów z MCE stosuje się materiał pochodzący z rozbiórki istniejących warstw (destrukt) bitumicznych, warstw związanych...
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The Substantial Improvement of Amphotericin B Selective Toxicity Upon Modification of Mycosamine with Bulky Substituents
PublicationAbstract: Background: It is assumed that the unfavorable selective toxicity of an antifungal drug Amphotericin B (AmB) can be improved upon chemical modification of the antibiotic molecule. Objective: The aim of this study was verification of the hypothesis that introduction of bulky substituents at the amino sugar moiety of the antibiotic may result in diminishment of mammalian vitro toxicity of thus prepared AmB derivatives. Methods:...
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Bacteriophages as an antistaphylococcal agent
PublicationRecently observed increase of infection caused by Staphylococcus aureus is currently one of the most important problem of clinical microbiology. Most of the strains responsible for the infections are a MRSA (methicillin resistant Staphylococcus aureus) strains. In this situation commonly used antibiotics are not sufficient. There is an urgent need to search for a new nonatibiotic treatment against this pathogen. In the literature...
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The structure, including stereochemistry, of levorin A1
PublicationThe constitution and stereostructure of levorin A1 1, an aromatic heptaeneantifungal antibiotic, was established on the basis of NMR studies, which contained DQFCOSY,ROESY, HSQC and HMBC experiments. Mycosamine moiety was used as an internalchiral probe to determine the absolute configuration of levorin A1 stereogenic centers: 13S,15R, 17S, 18R, 19S, 21R. The relative configuration of the remaining stereogenic centers wasassigned...
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Analysis of Validation and Simplification of Timber-Frame Structure Design Stage with PU-Foam Insulation
PublicationThe transition from experimental studies to the realm of numerical simulations is often necessary for further studies, but very difficult at the same time. This is especially the case for extended seismic analysis and earthquake-resistant design. This paper describes an approach to moving from the experimental testing of an elementary part of a wood-frame building structure to a numerical model, with the use of a commercial engineering...
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Tensile test of 1.4307 / X2CrNi18-9 / AISI 304L grade austenitic steel
Open Research DataShip structures and their components are build mainly of steel. Hull steel is used to build the hull structure. Some structural elements, such as RSW (Refrigerated See Water) tanks, or LNG (Liquid Natural Gas) tanks - gas transported at temperatures below -162° C, are build from austenitic steels. Austenitic steels have a different microstructure and...
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Tensile test of 1.4541 / X6CrNi18-10 / AISI 321 grade austenitic steel
Open Research DataShip structures and their components are build mainly of steel. Hull steel is used to build the hull structure. Some structural elements, such as RSW (Refrigerated See Water) tanks, or LNG (Liquid Natural Gas) tanks - gas transported at temperatures below -162° C, are build from austenitic steels. Austenitic steels have a different microstructure and...
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Polyurethanes as a carrier of drugs for gentamicin
PublicationGentamicin is one of the most popular drug and is widely used due to its antibiotic properties. 3% of world production of polyurethanes (PU) is dedicated to biomedical applications, where they can serve are parts of orthopedic prosthesis or artificial organs, disposable medical devices, wound and burn dressing, contact lenses among others. In the study, to obtain drug carriers, a combination of these two materials were prepared...
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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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Tensile test of 1.4571 / X6CrNiMoTi17-12-2 / AISI 316Ti grade austenitic steel
Open Research DataShip structures and their components are build mainly of steel. Hull steel is used to build the hull structure. Some structural elements, such as RSW (Refrigerated See Water) tanks, or LNG (Liquid Natural Gas) tanks - gas transported at temperatures below -162° C, are build from austenitic steels. Austenitic steels have a different microstructure and...
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Turmeric nanofiber-encapsulated natural product formulation act as a phytogenic feed additive—A study in broilers on growth performance, biochemical indices of blood, and E. coli in cecum
PublicationA phytogenic feed additive (PFA) formulation was prepared with bioactive molecules—curcuminoids, gingerol, and carvacrol by encapsulating in nanofiber isolated from turmeric spent (turmeric nanofiber, TNF). This formulation was completely characterized by scanning electron microscope, ultra performance liquid chromatography, and gas chromatography and evaluated for its efficacy. PFA-encapsulated TNF (PFA@TNF) considerably increased...
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Xanthone synthetic derivatives with high anticandidal activity and positive mycostatic selectivity index values
PublicationWith the current massive increases in drug-resistant microbial infection as well as the significant role of fungal infections in the death toll of COVID-19, discovering new antifungals is extremely important. Natural and synthetic xanthones are promising derivatives, although only few reports have demonstrated their antifungal mechanism of action in detail. Newly synthetized by us xanthone derivative 44 exhibited strong antifungal...
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Molecular Umbrellas Modulate the Selective Toxicity of Polyene Macrolide Antifungals
PublicationAntifungal polyene macrolide antibiotics Amphotericin B (AmB) and Nystatin (NYS) were conjugated through the ω-amino acid linkers with diwalled “molecular umbrellas” composed of spermidine-linked deoxycholic or cholic acids. The presence of “umbrella” substituents modulated biological properties of the antibiotics, especially their selective toxicity. Some of the AmB-umbrella conjugates demonstrated antifungal in vitro activity...
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Iso-Partricin, an Aromatic Analogue of Amphotericin B: How Shining Light on Old Drugs Might Help Create New Ones
PublicationPartricin is a heptaene macrolide antibiotic complex that exhibits exceptional antifungal activity, yet poor selective toxicity, in the pathogen/host system. It consists of two compounds, namely partricin A and B, and both of these molecules incorporate two cis-type bonds within their heptaenic chromophores: 28Z and 30Z. In this contribution, we have proven that partricins are susceptible to a chromophore-straightening photoisomerization...
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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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The loop impedance measurement
Open Research DataThe loop impedance measurement
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Visualizing Carotid Bodies With Doppler Ultrasound Versus CT Angiography: Preliminary Study
PublicationOBJECTIVE. The purpose of this article is to evaluate the utility of ultrasound in identifying carotid bodies (CBs) in patients with drug-resistant arterial hypertension. SUBJECTS AND METHODS. We enrolled 13 patients with drug-resistant hypertension into a trial for surgical CB excision. CT angiography (CTA) and Doppler ultrasound (DUS) of the cervical arteries were performed before surgery. CBs were identified in a blind manner...
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Effect of the Post-Weld Surface Condition on the Corrosion Resistance of Austenitic Stainless Steel AISI 304
PublicationSurfaces of welded elements made of corrosion-resistant (stainless) steels develop temper colours. The removal of thickened oxide layers off steels exposed to temperatures below 300°C is necessary and entails the restoring of high corrosion resistance of the stainless steel. The article presents tests concerned with the effect of a method applied to remove post-weld temper on the corrosion resistance of austenitic stainless steel...
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Pathological brain network activity: memory impairment in epilepsy
PublicationOur thinking, memory and cognition in general, relies upon precisely timed interactions among neurons forming brain networks that support cognitive processes. The surgical evaluation of drug-resistant epilepsy using intracranial electrodes provides a unique opportunity to record directly from human brain and to investigate the coordinated activity of cognitive networks. In this issue of Neurology®, Kleen and colleagues1 implicate...
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Cavitation Erosion of Nodular Cast Iron - Microstructural Effects
PublicationThe paper deals with susceptibility of nodular cast iron with ferritic-pearlitic matrix on cavitation erosion. Cavitation tests were carried out with the use of a cavitation erosion vibratory apparatus employing a vibration exciter operated at frequency of 20 kHz. The study allowed to determine the sequence of subsequent stages in which microstructure of cast iron in superficial regions is subject to degradation. The first features...
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Phylogenetic relationship and antimicrobial resistance in Escherichia coli isolated from the Reda River and the Oliwski Stream, Northern Poland = Lekooporność i przynależność filogenetyczna szczepów Escherichia Coli izolowanych z rzeki Redy i Potoku Oliwskiego
PublicationThe high abundance of fecal bacteria in surface water is usually related to poor agricultural practice, pollution caused by domesticated and wild animals as well as with septic tank failures. Identification of fecal contamination sources seems to be crucial in order to effectively estimate the inherent risk. In this study, the phylogenetic relationship of 30 isolates of E. coli, originated from surface water, was estimated by employing...
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Impact of Initial Population on Evolutionary Path Planning Algorithm
PublicationIn this paper an impact of initial population on evolutionary path planning algorithm is presented. Tested algorithm is used to determine close to optimal shippaths in collision avoidance situation. For this purpose a path planning problem is defined. A specific structure of the individual path and fitness function is presented. For the simulation purposes a close to real tested environment is created. Four tests are performed....
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Comparative molecular modelling of biologically active sterols
PublicationMembrane sterols are targets for a clinically important antifungal agent – amphotericin B. The relatively specific antifungal action of the drug is based on a stronger interaction of amphotericin B with fungal ergosterol than with mammalian cholesterol. Conformational space occupied by six sterols has been defined using the molecular dynamics method to establish if the conformational features correspond to the preferential interaction...
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Impact of Initial Population on Evolutionary Path Planning Algorithm
PublicationIn this paper an impact of initial population on evolutionary path planning algorithm is presented. Tested algorithm is used to determine close to optimal ship paths in collision avoidance situation. For this purpose a path planning problem is defined. A specific structure of the individual path and fitness function is presented. For the simulation purposes a close to real tested environment is created. Four tests are performed....
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Aspects of intergranular corrosion of AISI 321 stainless steel in high-carbon-containing environments
PublicationPurpose – The purpose of this paper is to present a case study of unexpected sensitization to intergranular corrosion of highly resistant AISI 321 steel in petrochemical conditions, where it was subjected to the simultaneous influence of elevated temperature of 250°C and vapors from the asphalt production process. Design/methodology/approach – Corrosion coupons were exposed in an installation carrying asphalt vapors. To identify...
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Secured wired BPL voice transmission system
PublicationDesigning a secured voice transmission system is not a trivial task. Wired media, thanks to their reliability and resistance to mechanical damage, seem an ideal solution. The BPL (Broadband over Power Line) cable is resistant to electricity stoppage and partial damage of phase conductors, ensuring continuity of transmission in case of an emergency. It seems an appropriate tool for delivering critical data, mostly clear and understandable...
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Ciprofloxacin-modified degradable hybrid polyurethane-polylactide porous scaffolds developed for potential use as an antibacterial scaffold for regeneration of skin
PublicationThe aim of the performed study was to fabricate an antibacterial and degradable scaffold that may be used in the field of skin regeneration. To reach the degradation criterion for the biocompatible polyurethane (PUR), obtained by using amorphous α,ω-dihydroxy(ethylene-butylene adipate) macrodiol (PEBA), was used and processed with so-called “fast-degradable” polymer polylactide (PLA) (5 or 10 wt %). To meet the antibacterial requirement...
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Natural Products Counteracting Cardiotoxicity during Cancer Chemotherapy: The Special Case of Doxorubicin, a Comprehensive Review
PublicationCardiotoxicity 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...
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Quest for the Molecular Basis of Improved Selective Toxicity of All-Trans Isomers of Aromatic Heptaene Macrolide Antifungal Antibiotics
PublicationThree aromatic heptaene macrolide antifungal antibiotics, Candicidin D, Partricin A (Gedamycin) and Partricin B (Vacidin) were subjected to controlled cis-trans to all trans photochemical isomerization. The obtained all-trans isomers demonstrated substantially improved in vitro selective toxicity in the Candida albicans cells: human erythrocytes model. This effect was mainly due to the diminished hemotoxicity. The molecular modeling...
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Transport deficiency is the molecular basis of Candida albicans resistance to antifungal oligopeptides
Publication(FMDP), an inhibitor of glucosamine-6-phosphate synthase, exhibited growth inhibitory activity against Candida albicans, with minimal inhibitory concentration values in the 0.05–50 mg/L range. Uptake by the peptide permeases was found to be the main factor limiting an anticandidal activity of these compounds. Di- and tripeptide containing FMDP (F2 and F3) were transported by Ptr2p/Ptr22p peptide transporters (PTR) and FMDP-containing...
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RecA Proteins from Deinococcus geothermalis and Deinococcus murrayi - Cloning, Purification and Biochemical Characterisation
PublicationEscherichia coli RecA plays a crucial role in recombinational processes, the induction of SOS response and mutagenic lesion bypasses. It has also been demonstrated that RecA protein is indispensable when it comes to the reassembly of shattered chromosomes in gamma-irradiated Deinococcus radiodurans, one of the most radiation-resistant organisms known. Moreover, some functional differences between E. coli and D. radiodurans RecA...
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Straightening of ship hull structure made of 316L stainless steel - tensile test of water cooled materia
Open Research DataThe AISI 316L type steel belongs to the group of chromium-nickel stainless steels. They are determined according to European standards as X2CrNiMo17-12-2 and belong to the group of austenitic stainless steels. Steels of this group are used for elements working in seawater environments, for installations in the chemical, paper, and food, industries,...
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Straightening of ship hull structure made of 316L stainless steel - tensile test of reference material materia (transverse direction)
Open Research DataThe AISI 316L type steel belongs to the group of chromium-nickel stainless steels. They are determined according to European standards as X2CrNiMo17-12-2 and belong to the group of austenitic stainless steels. Steels of this group are used for elements working in seawater environments, for installations in the chemical, paper, and food, industries,...
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Straightening of ship hull structure made of 316L stainless steel - tensile test of reference material materia (longitudinal direction)
Open Research DataThe AISI 316L type steel belongs to the group of chromium-nickel stainless steels. They are determined according to European standards as X2CrNiMo17-12-2 and belong to the group of austenitic stainless steels. Steels of this group are used for elements working in seawater environments, for installations in the chemical, paper, and food, industries,...
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Straightening of ship hull structure made of 316L stainless steel - microstructure of naturally colled material
Open Research DataThe AISI 316L type steel belongs to the group of chromium-nickel stainless steels. They are determined according to European standards as X2CrNiMo17-12-2 and belong to the group of austenitic stainless steels. Steels of this group are used for elements working in seawater environments, for installations in the chemical, paper, and food, industries,...
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Straightening of ship hull structure made of 316L stainless steel - microstructure of water cooled material
Open Research DataThe AISI 316L type steel belongs to the group of chromium-nickel stainless steels. They are determined according to European standards as X2CrNiMo17-12-2 and belong to the group of austenitic stainless steels. Steels of this group are used for elements working in seawater environments, for installations in the chemical, paper, and food, industries,...
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Straightening of ship hull structure made of 316L stainless steel - microstructure of reference material
Open Research DataThe AISI 316L type steel belongs to the group of chromium-nickel stainless steels. They are determined according to European standards as X2CrNiMo17-12-2 and belong to the group of austenitic stainless steels. Steels of this group are used for elements working in seawater environments, for installations in the chemical, paper, and food, industries,...
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Straightening of ship hull structure made of 316L stainless steel - tensile test of naturally cooled material
Open Research DataThe AISI 316L type steel belongs to the group of chromium-nickel stainless steels. They are determined according to European standards as X2CrNiMo17-12-2 and belong to the group of austenitic stainless steels. Steels of this group are used for elements working in seawater environments, for installations in the chemical, paper, and food, industries,...
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Implant system for treatment of the orbital floor defects of blowout fractures in the maxillofacial region using polypropylene yarn and bioactive bone cement
PublicationFractures in the craniofacial region are a serious problem in terms of treatment. The most reasonable solution is the use of individual implants dedicated to a specific patient. The aim of this study was to develop the implant system specifically for treatment of the orbital floor defects of blowout fractures of maxillofacial region, using polypropylene yarn and bone cement. Three types of bone cement were used to fix the polypropylene...
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Quantitative Analysis of Biofilm Formed on Vascular Prostheses by Staphylococcus Epidermidis with Different ica and aap Genetic Status
PublicationOBJECTIVES: This study aims to examine biofilm formed on vascular prostheses by Staphylococcus epidermidis with different ica and aap genetic status, and to evaluate the effect of antibiotic-modified prostheses on bacterial colonization. METHODS: Biofilm formation was determined using fluorescence microscopy imaging. Quantitative analysis was conducted using the biofilm coverage ratio (BCR) calculations. RESULTS: Our investigations...
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The influence of humic substances in treated sewage on the quality of surface waters
PublicationAt present the evaluation of WWTP effectiveness is based upon organic matter and nutrients removal. Recently it was found out that sewage treatment leads to formation of resistant to biochemical degradation organic compounds, similar to humic acids. The humic acids formed during sewage treatment process play diversified functions when discharged to surface waters - for instance they can act as carriers of hydrophobic organic pollutants...
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The overexpression of CPR and P450 3A4 in pancreatic cancer cells changes the metabolic profile and increases the cytotoxicity and pro-apoptotic activity of acridine antitumor agent, C-1748
PublicationDrug resistance is one of the major cause of pancreatic cancer treatment failure. Thus, it is still imperative to develop new active compounds and novel approach to improve drug efficacy. Here we present 9-amino-1-nitroacridine antitumor agent, C-1748, developed in our laboratory, as a candidate for pancreatic cancer treatment. We examined (i) the cellular response of pancreatic cancer cell lines: Panc-1, MiaPaCa-2, BxPC-3 and...
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Human-associated bacteria and their mobile genetic elements - important minority in wastewater and wastewater impacted ecosystems
PublicationSince human-associated bacteria have been recognized as vectors in two - way gene transmission between the pathogenic and environmental populations, health hazard connected with wastewater discharge requires reevaluation. In this paper the particular attention was given to antimicrobial-resistance of Escherichia coli and enterococci isolated from wastewater and wastewater impacted environments. The obtained results showed that...
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Essential oils as potential anti-staphylococcal agents
PublicationAntibiotic therapy of staphylococcal mastitis is characterized by significantly lower cure rates compared to infections caused by other microorganisms. Thus, it is necessary to search for new, alternative, non-antibiotic agents that are effective in the eradication of these bacteria. The aim of our research was to investigate the antimicrobial, especially anti-staphylococcal potential of a large collection (n=36) of essential oils...
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Marcin Wekwejt dr inż.
PeopleMarcin Wekwejt, absolwent studiów inżynierskich w inż. biomedycznej (2016; Politechnika Bydgoska im. J. i J. Śniadeckich & Collegium Medicum im. L. Rydygiera), studiów magisterskich w inż. mechaniczno-medycznej (2018; Politechnika Gdańska & Gdański Uniwersytet Medyczny) oraz studiów doktoranckich w dyscyplinie inż. materiałowej (2021, Politechnika Gdańska). Uzyskał z wyróżnieniem stopień naukowy doktora nauk inżynieryjno-technicznych...
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Acoustic Processor of the Mine Countermeasure Sonar
PublicationThis paper presents the concept of an acoustic processor of the mine countermeasure sonar. Developed at the Department of Marine Electronics Systems, Gdansk University of Technology, the acoustic processor is an element of the MG-89, an underwater acoustic station. The focus of the article is on the modules of the processor. They are responsible for sampling analogue signals and implementing the algorithms controlling the measurement...
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Proteolysis of whey protein isolates in nanoemulsion systems: impact of nanoemulsification and additional synthetic emulsifiers
PublicationNanoemulsions are currently of interest in the functional food sector because their small droplet size (100–500 nm) provides a number of potential advantages over conventional emulsions. This study concerned the behavior of nanoemulsions stabilized with whey proteins and two synthetic emulsifiers (Tween 80 and Croduret), and exposed to conditions simulating the human upper gastrointestinal tract. In particular, the effect of synthetic...
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The problem of infections associated with implants – an overview
PublicationImplant-associated infections are serious and relatively common complication that leads to implant loss. The purpose of this paper is to gather knowledge about this issue. A literature review of the epidemiology, risk factors and pathogenesis of infections related to implants was carried out. This position collects data on commonly used implants and infections associated with them from various fields of medicine and contains classifications...
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Evaluation of Langmuir and Freundlich Isotherms for Removal of Cephalexin and Tetracycline Antibiotics By Sistan Sand from Water and Wastewater Samples
PublicationIn this research, Sistan sand was used as a natural and inexpensive sorbent for removal of cephalexin and tetracycline antibiotics from water and wastewater samples. For a concentration 60.0 mg L-1 of cephalexin, optimum removal conditions were: pH of the sample 3.0, adsorbent amount 1.0 g, contact time 20.0 min, added amount of sodium chloride to adjust the ionic strength of the solution 7.0 g L-1. Langmuir isotherm was the best...
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Biofilm bakteryjny uropatogennych szczepów E. coli Dr+ jako czynnik indukujący przewlekłość zakażeń dróg moczowych ograniczający ich leczenie
PublicationZakażenia dróg moczowych (ZUM) stanowią jedne z najczęściej występujących infekcji bakteryjnych, dotykających każdego roku miliony osób na świecie. Problematyka tych zakażeń wynika z ich przewlekłości i nawrotów, pomimo stosowania terapii antybiotykowej oraz ciągle wzrastającej lekooporności uropatogenów je wywołujących. Dominującym czynnikiem etiologicznym ZUM są uropatogenne szczepy E. coli (UPECs), wykazujące zdolność do adhezji,...
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Cząsteczki mikroRNA - nowy biologicznie aktywny składnik mleka kobiecego
PublicationCząsteczki mikroRNA są krótkimi, niekodującymi oligonukleotydami odpowiadającymi za potranskrypcyjną regulację ekspresji genów. W wyniku ich aktywności kontrolowanych jest wiele procesów komórkowych oraz szlaków sygnalizacyjnych. Od 2010 roku wiadomo, że wchodzą one w skład mleka kobiecego, które obecnie uznaje się za jedno z najbogatszych pokarmowych źródeł mikroRNA. Funkcje tych cząsteczek w organizmie karmionego mlekiem matki...
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A continual model of a damaged medium used for analyzing fatigue life of polycrystalline structural alloys under thermal–mechanical loading
PublicationThe main physical laws of thermal–plastic deformation and fatigue damage accumulation processes in polycrystalline structural alloys under various regimes of cyclic thermal–mechanical loading are considered. Within the framework of mechanics of damaged media, a mathematical model is developed that describes thermal–plastic deformation and fatigue damage accumulation processes under low-cycle loading. The model consists of three...
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Modification of gradient HPLC method for determination of small molecules' affinity to human serum albumin under column safety conditions: Robustness and chemometrics study
PublicationIn the early stages of drug discovery, beyond the biological activity screening, determining the physicochemical properties that affect the distribution of molecules in the human body is an essential step. Plasma protein binding (PPB) is one of the most important investigated endpoints. Nevertheless, the methodology for measuring %PPB is significantly less popular and standardized than other physicochemical properties, like lipophilicity....
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Corrosion degradation of spacers – examination of changes in bone cement coating.
PublicationSpacer is a special implant used at the time of infection after endoprosthetic surgery. It consists of a metal core and bone cement coating with an antibiotic. In the human body spacers are exposed to degradation processes. This paper looks at the effect of corrosion on spacers. Electrochemical corrosion tests were performer on titanium pins with bone cement coating in two solutions: Ringer’s solution and artificial...
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Peptide dendrimers as antifungal agents and carriers for potential antifungal agent—N3‐(4‐methoxyfumaroyl)‐(S)‐2,3‐ diaminopropanoic acid—synthesis and antimicrobial activity
PublicationA series of peptide dendrimers and their conjugates with antimicrobial agent FMDP (N3‐(4‐methoxyfumaroyl)‐(S)‐2,3‐diamino‐propanoic acid) were synthesized. The obtained compounds were tested for the antibacterial and antifungal activity. All novel dendrimers displayed much better activity against the tested strains than FMDP itself. Moreover, their conjugates with FMDP also exhibited antimicrobial activity. The most promising molecules...
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Microwave heat treatment application to pasteurization of human milk
PublicationA prototype of microwave pasteurizer has been proposed as an alternative for holder pasteurization (HP) routinely used in Human Milk Bank (HMB), ensuring microbiological safety of human milk (HM). It was shown that the time of heat generation was about 15–16 min shorter by applying the microwave than in HP. Total inactivation of heat-sensitive bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus...
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Acoustic Processor of the MCM Sonar
PublicationThis paper presents the concept of an acoustic processor of the mine countermeasure sonar. Developed at the Department of Marine Electronics Systems, Gdansk University of Technology, the acoustic processor is an element of the MG-89, a modernised underwater acoustic station. The focus of the article is on the modules of the processor. They are responsible for sampling analogue signals and implementing the algorithms controlling...
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Influence of controlled crystallization and SrF2 content on the structure and properties of Eu3+ doped phosphate glasses
PublicationNew phosphate glasses and glass-ceramics P2O5–Bi2O3–K2O–Nb2O5-SrF2 doped with Eu were synthesized and studied in this work. The influence of the SrF2 content (0–15 mol%) and the parameters of the heat treatment on their structural and optical properties were investigated. For the above purpose, the structural characterization by FTIR spectroscopy and XRD measurements was carried out, which showed a significant effect of SrF2 on...
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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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Biomechanical testing of bioactive bone cements – a comparison of the impact of modifiers: antibiotics and nanometals
PublicationApart from its bone filler and fracture stabilizing function, bone cement can be used as a carrier of bioactive substances, and such modified bone cement can protect the implant against microorganisms, treat local infections and combat bacteria introduced during the surgical procedure. In this paper, the effects of modifying antibiotics and nanosilver on the biomechanical properties of bone cement were examined. The following tests...
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Antimicrobial and Antiproliferative Coatings for Stents in Veterinary Medicine—State of the Art and Perspectives
PublicationMicrobial colonization in veterinary stents poses a significant and concerning issue in veterinary medicine. Over time, these pathogens, particularly bacteria, can colonize the stent surfaces, leading to various complications. Two weeks following the stent insertion procedure, the colonization becomes observable, with the aggressiveness of bacterial growth directly correlating with the duration of stent placement. Such microbial...
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Evidence of mutations conferring resistance to clarithromycin in wastewater and activated sludge
PublicationThe occurrence of clarithromycin in wastewater samples and of the activated sludge bacteria possibly resistant to this pharmaceutical was the object of the study. Samples of wastewater or activated sludge were taken from a municipal wastewater treatment plant in summer and winter and characterised regarding their clarithromycin concentrations and the presence of nucleic acid fragments (Cla-sequences) known to be responsible for...
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The effect of convective heating and microwave heating on antioxidant enzymes in pooled mature human milk
PublicationThe effects of convective and microwave heating at constant temperature (62.5, 66 and 70 °C) on the activity of antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPx) in pooled mature human milk were compared. Activities of the enzymes were determined using spectrophotometric kits. Activity of GPx decreased significantly in the first stage of heating when milk samples were warmed to pasteurisation...
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Corrosion behavior of hydrogen charged super duplex stainless steel welded joints
PublicationThe electrochemical behavior of the weld metal, heat-affected zone (HAZ), and base material of super duplex stainless steel (SDSS) welded joints, made with the application of flux-cored arc welding (FCAW) and submerged arc welding (SAW), were investigated with the use of metallographic examinations (optical microscopy and scanning electron microscopy), potentiodynamic polarization measurements and total hydrogen content determination...
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Hybrid analogues of SFTI-1 modified in P1 position by β- and γ-amino acids and N-substituted β-alanines
PublicationA series of compounds containing either non-proteinogenic beta-/gamma-amino acids or N-substituted beta-alanine residues (beta-peptoid units) in P-1 specificity position were synthesized based on the structure of sunflower trypsin inhibitor 1 (SFTI-1). The compounds were synthesized on a solid support; the N-substituted beta-alanines (beta Nhlys and beta Nhphe) were introduced into a peptidomimetic chain via a two-step approach...
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Evaluation of reformer tubes degradation after long term operation
PublicationPurpose of this paper is to show the effect of long-term service at elevated temperatures on microstructural changes of cast steel reformer tubes made of the alloy IN-519 (24%Cr, 24%Ni, Nb). The relationship between mechanical properties and microstructure degradation is discussed. Investigations were performed on five tubes taken from ammonia reformer furnace. Tubes worked at temperature of 880C and 3,2 MPa pressure. The operation...
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Progress in used tyres management in the european union: a review
PublicationThe dynamic increase in the manufacture of rubber products, particularly those used in the automobile industry, is responsible for a vast amount of wastes, mostly in the form of used tyres, of which more than 17 million tonnes are produced globally each year. The widely differing chemical compositions and the cross-linked structures of rubber in tyres are the prime reason why they are highly resistant to biodegradation, photochemical...
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The Effect of C45 Carbon Black-Phosphomolybdic Acid Nanocomposite on Hydrogenation and Corrosion Resistance of La2Ni9Co Hydrogen Storage Alloy
PublicationIn this paper, we analysed the influence of corrosion processes and the addition of a carbon black-heteropoly phosphomolybdic acid (C45-MPA) nanocomposite on the operating parameters of a hydride electrode obtained on the basis of the intermetallic compound La2Ni9Co. The electrochemical properties of negative electrodes for NiMH batteries were studied using galvanostatic charge/discharge curves, the potentiostatic method, and electrochemical...
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CFFT columns in road through railroad crossings
PublicationThere were 12801 road through railroad one-level crossings in Poland in 2018. 215 accidents happened at them in 2018. In order to increase safety in rail and road traffic two-level crossings should be used. They are definitely safer and make the traffic more smooth. In the design and construction of two-level intersections of railway and road or path columns of circular cross-section are often used. They can be successfully replaced...
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Peptide Permeases in Candida albicans
PublicationAims: The aim of this work was to characterize oligopeptide uptake in Candida albicans mutants in which the genes encoding putative peptide permeases were selectively disrupted. Initial velocities of transport of model oligopeptides, (Ala)2, (Ala)3, (Ala)4, and sensitivity of mutants to antifungal oligopeptides containing N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP) were determined and compared to those of the wild-type...
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Antimicrobial resistance of Pseudomonas spp. isolated from wastewater and wastewater-impacted marine coastal zone
PublicationIn this study, species distribution and antimicrobial susceptibility of cultivated Pseudomonas spp. were studied in influent (INF), effluent (EFF), and marine outfall (MOut) of wastewater treatment plant (WWTP). The susceptibility was tested against 8 antimicrobial classes, active against Pseudomonas spp.: aminoglycosides, carbapenems, broad-spectrum cephalosporins from the 3rd and 4th generation, extended-spectrum penicillins,...
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Regulated Control of the Assembly and Diversity of LPS by Noncoding sRNAs
PublicationThe outer membrane (OM) of Gram-negative bacteria is asymmetric due to the presence of lipopolysaccharide (LPS) facing the outer leaflet of the OM and phospholipids facing the periplasmic side. LPS is essential for bacterial viability, since it provides a permeability barrier and is a major virulence determinant in pathogenic bacteria. In Escherichia coli, several steps of LPS biosynthesis and assembly are regulated by the RpoE...
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How do sterols determine the antufungal activitiy of amphotericin B? Free energy of binding between the drug and its membrane targets.
PublicationAmphotericin B (AmB) is a well-known polyene antibiotic used to treat systemic fungal infections. It is commonly accepted that the presence of sterols in the membrane is essential for the AmB biological activity, that is, for the formation of transmembrane ion channels. The selective toxicity of AmB for fungal cells is attributed to the fact that it is more potent against fungal cell membranes containing ergosterol than against...
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Właściwości katalityczne i biomedyczne związków zawierających jony rutenu(II) oraz rutenu(III)
PublicationRuthenium complexes appear in scientific publications mainly as catalysts in the olefins metathesis process. In this review, we want to indicate the research niche regarding the use of ruthenium(II) and ruthenium(III) complexes in other catalytic processes, i.e. polymerization or epoxidation of olefins and depolymerization. We would like to combine the catalytic properties of ruthenium(II,III) complex compounds with their biomedical...
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The Many Faces of Enterococcus spp.—Commensal, Probiotic and Opportunistic Pathogen
PublicationEnterococcus spp. are Gram-positive, facultative, anaerobic cocci, which are found in the intestinal flora and, less frequently, in the vagina or mouth. Enterococcus faecalis and Enterococcus faecium are the most common species found in humans. As commensals, enterococci colonize the digestive system and participate in the modulation of the immune system in humans and animals. For many years reference enterococcal strains have...
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Subjective Quality Evaluation of Speech Signals Transmitted via BPL-PLC Wired System
PublicationThe broadband over power line – power line communication (BPL-PLC) cable is resistant to electricity stoppage and partial damage of phase conductors. It maintains continuity of transmission in case of an emergency. These features make it an ideal solution for delivering data, e.g. in an underground mine environment, especially clear and easily understandable voice messages. This paper describes a subjective quality evaluation of...
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Microstructure and Properties of Electroless Ni-P/Si3N4 Nanocomposite Coatings Deposited on the AW-7075 Aluminum Alloy
PublicationThe article presents the results of mechanical and tribological tests of Ni-P/Si3N4 nanocomposite coatings deposited on the AW-7075 aluminum alloy using the chemical reduction method. The influence of the chemical composition on the Vickers microhardness determined by the DSI method was examined. The nanocomposite layers were made of Si3N4 silicon nitride in a polydisperse powder with a particle size ranging from 20 to 25 nm. The...
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Influence of process of straightening ship hull structure made of 316L stainless steel on corrosion resistance and mechanical properties
PublicationThe AISI 316L type steel belongs to the group of chromium-nickel stainless steels. They are determined according to European standards as X2CrNiMo17-12-2 and belong to the group of austenitic stainless steels. Steels of this group are used for elements working in seawater environments, for installations in the chemical, paper, and food, industries, for architectural elements, and many others. The chemical composition of corrosion-resistant...
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Tribological Properties of Ni-P/Si3N4 Nanocomposite Layers Deposited by Chemical Reduction Method on Aluminum Alloy AW-7075
PublicationThe article presents the results of tribological tests of Ni-P/Si3N4 nanocomposite and Ni-P nickel layers deposited on the AW-7075 aluminum alloy by chemical reduction method, and the AW-7075 alloy without coating. Nanocomposite layers were produced using Si3N4 siliconnitride in the form of a polydisperse powder whose particle sizes ranged from 20 to 25 nm. The influence of the content of the dispersion phase layer material on...
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Regulated Assembly of LPS, Its Structural Alterations and Cellular Response to LPS Defects
PublicationDistinguishing feature of the outer membrane (OM) of Gram-negative bacteria is its asymmetry due to the presence of lipopolysaccharide (LPS) in the outer leaflet of the OM and phospholipids in the inner leaflet. Recent studies have revealed the existence of regulatory controls that ensure a balanced biosynthesis of LPS and phospholipids, both of which are essential for bacterial viability. LPS provides the essential permeability...
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Antibody Cross-Reactivity in Serodiagnosis of Lyme Disease
PublicationLyme disease is a tick-borne disease caused by spirochetes belonging to the Borrelia burgdorferi sensu lato complex. The disease is characterized by a varied course; therefore, the basis for diagnosis is laboratory methods. Currently, a two-tiered serological test is recommended, using an ELISA as a screening test and a Western blot as a confirmatory test. This approach was introduced due to the relatively high number of false-positive...
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Surgical Site Infection after Breast Surgery: A Retrospective Analysis of 5-Year Postoperative Data from a Single Center in Poland
PublicationBackground and Objectives: Surgical site infection (SSI) is a significant complication of non-reconstructive and reconstructive breast surgery. This study aimed to assess SSI after breast surgery over five years in a single center in Poland. The microorganisms responsible for SSI and their antibiotic susceptibilities were determined. Materials and Methods: Data from 2129 patients acquired over five years postoperatively by the...
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Composite Polyurethane-Polylactide (PUR/PLA) Flexible Filaments for 3D Fused Filament Fabrication (FFF) of Antibacterial Wound Dressings for Skin Regeneration
Publicationhis paper addresses the potential application of flexible thermoplastic polyurethane (TPU) and poly(lactic acid) (PLA) compositions as a material for the production of antibacterial wound dressings using the Fused Filament Fabrication (FFF) 3D printing method. On the market, there are medical-grade polyurethane filaments available, but few of them have properties required for the fabrication of wound dressings, such as flexibility...
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Diaryl Sulfide Derivatives as Potential Iron Corrosion Inhibitors: A Computational Study
PublicationThe present work aimed to assess six diaryl sulfide derivatives as potential corrosion inhibitors. These derivatives were compared with dapsone (4,4′-diaminodiphenyl sulfone), a common leprosy antibiotic that has been shown to resist the corrosion of mild steel in acidic media with a corrosion efficiency exceeding 90%. Since all the studied compounds possess a common molecular backbone (diphenyl sulfide), dapsone was taken as the...
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May Staphylococcus lugdunensis Be an Etiological Factor of Chronic Maxillary Sinuses Infection?
PublicationStaphylococcus lugdunensis is an opportunistic pathogen found in the healthy human skin microbiome bacterial community that is able to cause infections of diverse localization, manifestation, and course, including laryngological infections, such as necrotizing sinusitis. Chronic maxillary sinusitis is a disease present in up to one third of European and American populations, and its etiology is not fully described. Within this...
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Analysis of Transparent Concrete as an Innovative Material Used in Civil Engineering
PublicationSince the dawn of history concrete has been, right behind stone and brick, one of the oldest building materials. The ancient Romans took advantage of its opportunities. They constructed amazing architectural objects, which survived centuries as whole buildings or parts of them. Concrete is so ubiquitous, that when we are walking in a newer districts of cities we are virtually surrounded by concrete from everywhere. Sometimes...
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Behaviour of Asymmetric Structure with Base Isolation Made of Polymeric Bearings
PublicationEarthquake-induced ground motions are the most severe and unpredictable threats to the structures all around the world. Seismic excitations cause a lot of damage in a wide variety of ways, leaving thousands of casualties in their wake. Due to randomness of earthquake occurrence, lack of visible causes and their power of destructiveness, structural engineers need to develop new technical solutions and protection systems against...