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Wyniki wyszukiwania dla: GRAPHENE DERIVATIVES
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Indirect Measurement of Motor Current Derivatives in PMSM Sensorless Drives
PublikacjaMotor current derivatives contain useful information for control algorithms, especially in sensorless electric drives. The measurement of motor current derivatives in electric motors supplied by voltage source inverter can be performed using di/dt transducers. However, in such a solution additional sensors have to be installed, e.g. Rogowski coils. Another approach is to measure current derivatives indirectly – by oversampling...
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Fractional Problems with Right-Handed Riemann-Liouville Fractional Derivatives
PublikacjaIn this paper, we investigate the existence of solutions for advanced fractional differential equations containing the right-handed Riemann-Liouville fractional derivative both with nonlinear boundary conditions and also with initial conditions given at the end point T of interval [0,T ]. We use both the method of successive approximations, the Banach fixed point theorem and the monotone iterative technique, as well. Linear problems...
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Synthesis and biological activity of mycophenolic acid-amino acid derivatives
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Alkylation of 9-substituted guanine derivatives with α,ω-dihaloalkanes
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Studies on the influence of β-cyclodextrin derivatives on the physical stability of famotidine
PublikacjaThe usage of Fourier transform infrared spectroscopy, near infrared spectroscopy, differential scanning calorimetry and microscopy is presented in this work focused on the exploration of the effect of CD on the physical stability of famotidine (FAM). The most significant information was achieved by analysis of the second derivatives ofnear infrared (NIR) spectra recorded. Changes in the shape of spectra derivatives allow...
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Photophysics of 7-Hydroxytetrahydroisoquinoline-3-carboxylic Acid and Its Derivatives
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Antimicrobial and surface activity of 1-alkyl-3-methylimidazolium derivatives
PublikacjaWiedza na temat zależności struktura-aktywność umożliwia projektowanie i syntezę nowych kationowych związków amfifilowych ze zoptymalizowaną aktywnością antymikrobową na rzecz przyszłego rozwoju nowych środków dezynfekujących, sanityzujących czy konserwujących. Potrzeba projektowania i identyfikowania nowych związków posiadających właściwości przeciwbakteryjne jest rezultatem pojawienia się bardziej odpornych mikroorganizmów w...
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Prediction of antimicrobial activity of imidazole derivatives by artificial neural networks
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New Chalcones Derivatives With Potent Antitumor Activity And Their Metabolism In Vitro
PublikacjaChalcone derivatives exhibit a broad range of biological activities, with antioxidant and cytotoxic properties among the most studied. Despite numerous reports on chalcones as cytotoxic, and potentially anticancer agents, very little is know on their actual mechanism of activity. Generally, chalcones are considered as antimitotic agents, which interfere with tubulin assembly.We have recently developed a new class of chalcones with...
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The content of butyl- and phenyltin derivatives in the sediment from the Port of Gdansk
PublikacjaPróbki osadów portowych były pobierane dwukrotnie (2003 i 2005)z różnych nabrzeży w Porcie Gdańsk. Rdzenie o długości 25 cm były dzielone na warstwy o grubości 2 i 5cm i po odpowiednim przygotowaniu (w tym także analizie sitowej) były poddawane analizie na zawartość związkow cynoorganicznych.W analizowanych póbkach (o różnej granulacji cząstek osadu) wykryto i oznaczono względnie duże stężenie TBT, DBT, MBT oraz MPhT. Osady portowe...
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Supramolecular Interactions between β-Cyclodextrin and the Nucleobase Derivatives of Ferrocene
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Conjugation of polyethylenimine and its derivatives to carbon-encapsulated iron nanoparticles
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Natural composites based on polysaccharide derivatives: preparation and physicochemical properties
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Numerical Estimation of Hull Hydrodynamic Derivatives in Ship Maneuvering Prediction
PublikacjaPrediction of the maneuvering characteristics of the ship at the design stage can be done by means of model tests, computational simulations or a combination of both. The model tests can be realized as direct simulation of the standard maneuvers with the free running model, which gives the most accurate results, but is also the least affordable as it requires very large tank or natural lake, as well as complex equipment of the...
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Anticancer Properties of Amino Acid and Peptide Derivatives of Mycophenolic Acid
PublikacjaBackground: Although Mycophenolic Acid (MPA) is applied as prodrugs in clinic as an immunosuppressant, it also possesses anticancer activity. MPA acts as Inosine-5’-Monophosphate Dehydrogenase (IMPDH) inhibitor, where the carboxylic group at the end of the side chain interacts with Ser 276 of the enzyme via hydrogen bonds. Therefore, MPA derivatives with other polar groups indicated high inhibition too. On the other hand, potent...
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NUMERICAL ESTIMATION OF HULL HYDRODYNAMIC DERIVATIVES IN SHIP MANOUVERING PREDICTION
PublikacjaOperating in crowded waterways pose a risk of accidents and disasters due to maneuvering limitations of the ship. In order to predict ship’s maneuvering characteristics at the design stage, model tests are often executed as the most accurate prediction tool. Two approaches can be distinguished here: free running model tests and numerical simulations based on planar motion model with the use of hydrodynamic derivatives obtained...
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Immunosuppressive properties of amino acid and peptide derivatives of mycophenolic acid
PublikacjaMycophenolic acid (MPA) was coupled with amino acids and biologically active peptides including derivatives of tuftsin to modify its immunosuppressive properties. Both amino acid unit in the case of simple MPA amides and modifications within peptide moiety of MPA - tuftsin conjugates influenced the observed activity. Antiproliferative potential of the obtained conjugates was investigated in vitro and MPA amides with threonine methyl...
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Expedited antenna optimization with numerical derivatives and gradient change tracking
PublikacjaDesign automation has been playing an increasing role in the development of novel antenna structures for various applications. One of its aspects is electromagnetic (EM)-driven design closure, typically applied upon establishing the antenna topology, and aiming at adjustment of geometry parameters to boost the performance figures as much as possible. Parametric optimization is often realized using local methods given usually reasonable...
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Therapeutic Potential of Carnosine and Its Derivatives in the Treatment of Human Diseases
PublikacjaDespite significant progress in the pathogenesis, diagnosis, treatment, and prevention of cancer and neurodegenerative diseases, their occurrence and mortality are still high around theworld. The resistance of cancer cells to the drugs remains a significant problem in oncology today,while in the case of neuro-degenerative diseases, therapies reversing the process are still yet to be found. Furthermore, it is important to seek new...
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Synthesis of ester derivatives of propylene glycol in the presence of zinc carboxylates.
PublikacjaZbadano wpływ temperatury i stężenia karboksylanów cynku na przebieg estryfikacji glikolu propylenowego kwasami tłuszczowymi. Otrzymano emulgatory, w których maksymalne stężenie monoestru wynosiło 55-57%.
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Synthesis and biological activity of mycophenolic acid-amino acid derivatives
PublikacjaIn search of new immunosuppressants, mycophenolic acid (MPA) was coupled with amino acid methyl esters followed by hydrolysis to analogs bearing free carboxylic groups. The obtained compunds were tested in vitro as growth inhibitors of lymphoid cell line (Jurkat) and human peripheral blood mononuclear cells (PBMC) from healthy donors. According to obtained results recovering of free carboxylic group increased their activity. Additionally,...
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Reduction of Derivative pipeline effort in water turbine
PublikacjaThe paper presents an approach to evaluate and reduce the effort of the derivative pipeline in a water turbine of a hydrostatic power station in its vulnerable spots. Potential places of the biggest effort of the structure, as well as the coefficient of displacement and safety factor related to them were identified using FEM numerical method. Pipeline reinforcement was designed and made based on FEM analysis. Original technology...
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Antifungal action of the oxathiolone-fused chalcone derivative
PublikacjaAMG-148, pochodna chalkonu z pierścieniem oksatiolonowym, wykazuje aktywność przeciwgrzybową in vitro wobec szczepów grzybowych patogennych dla człowieka, z wartościami minimalnych stężeń hamujących wzrost mieszczących się w zakresie 1-16 mikrogramów na mililitr, natomiast w wyższych stężeniach związek ten działa grzybobójczo. Obecność głównych białek oporności wielolekowej, Cdr1p, Cgr2p lub Mdr1p nie wpływa znacząco na aktywność...
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Analysis of graphene multi-strip planar guiding structures with the use of spectral domain approach
PublikacjaSpectral domain approach is modified and used to analyze some simple structures containing graphene strips. The modification is simple and concerns the Green’s function only. Moreover, the method is combined with the recently published root finding algorithms, which significantly improve the efficiency of the analysis. The results obtained for a simple guiding structure is verified and the field displacement effect is confirmed.
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Dielectric properties of modified graphene oxide filled polyurethane nanocomposites and its correlation with rheology
PublikacjaThis study aims at investigating the dynamic mechanical, dielectric and rheological properties of reinforced polyurethane (PU) nanocomposites containing hydrophilic graphene oxide (GO) and/or hydrophobic modified graphene oxide (mGO) sheets. The organic modification of GO was performed with 4,4′-methylenebis (phenyl isocyanate) (MDI) and the samples were prepared by solvent mixing. We found that addition of mGO provides a more...
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I-V, dielectric, antibacterial, and robust EMI shielding effectiveness properties of graphene/Fe3O4
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Synthesis of 3-D Graphene via Combustion Synthesis of Magnesium and Calcium/Magnesium Oxalates
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Graphene-encapsulated iron nanoparticles as a non-viral vector for gene delivery into melanoma cells
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Three dimensional graphene/carbonized metal-organic frameworks based high-performance supercapacitor
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Well-Designed Porous Graphene Flakes for Lithium-Ion Batteries with Outstanding Rate Performance
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Could graphene construct an effective conducting network in a high-power lithium ion battery?
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Functionalization of graphene oxide coatings with phosphorus atoms and their corrosion resistance in sodium chloride environment
PublikacjaIn this work, we compared corrosion resistance of graphene oxide, and phosphorus functionalized reduced graphene oxide coatings obtained as a result of electrophoretic deposition on the copper substrate. Doping graphene oxide with phosphorus atoms was performed by a hydrothermal method in the presence of different amounts of phosphoric acid. Structural studies confirmed the insertion of phosphorus atoms into the graphene oxide...
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Morphology and the physical and thermal properties of thermoplastic polyurethane reinforced with thermally reduced graphene oxide
PublikacjaIn this study, thermally reduced graphene oxide (TRG)-containing polyurethane nanocomposites were obtained by the extrusion method. The content of TRG incorporated into polyurethane elastomer systems equaled 0.5, 1.0, 2.0 and 3.0 wt%. The morphology, static and dynamic mechanical properties, and thermal stability of the modified materials were investigated. The application of TRG resulted in a visible increase in material stiffness...
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Fabrication of 3D graphene/MoS2 spherical heterostructure as anode material in Li-ion battery
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The effect of boiling in a thermosyphon on surface tension and contact angle of silica and graphene oxide nanofluids
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Low temperature CVD growth of graphene nano-flakes directly on high K dielectrics
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The covalent and non-covalent conjugation of graphene oxide with hydroxycamptothecin in hyperthermia for its anticancer activity
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Interatomic potential suitable for the modeling of penta-graphene: Molecular statics/molecular dynamics studies
PublikacjaWe test the potentials available for elemental carbon, with the scope to choose the potential suitable for the modeling of penta-graphene, the latest two dimensional carbon allotrope. By using molecular statics and molecular dynamics simulations we show that there is only one potential e namely the Tersoff-type potential proposed by Erhart and Albe in 2005 e which is able to correctly describe all the important features of penta-graphene....
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Anisotropic mechanical behavior and auxeticity of penta-graphene: Molecular statics/molecular dynamics studies
PublikacjaWe investigate the mechanical properties of penta-graphene (PG), a recently proposed two-dimensional carbon allotrope using atomistic simulation techniques combined with the empirical description of interatomic interactions. We report on the dependence of its three in-plane mechanical moduli (i.e. Young's modulus, Poisson's ratio and shear modulus) on the deformation direction, strain and temperature. We show that PG displays a...
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3D Hierarchical Boron-Doped Diamond-Multilayered Graphene Nanowalls as an Efficient Supercapacitor Electrode
PublikacjaSynthesis of stable hybrid carbon nanostructure for high-performance supercapacitor electrode with long life-cycle for electronic and energy storage devices is a real challenge. Here, we present a one-step synthesis method to produce conductive boron-doped hybrid carbon nanowalls (HCNWs), where sp2-bonded graphene has been integrated with and over a three-dimensional curved wall-like network of sp3-bonded diamond. The spectroscopic...
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Continuum contact model for friction between graphene sheets that accounts for surface anisotropy and curvature
PublikacjaUnderstanding the interaction mechanics between graphene layers and co-axial carbon nanotubes (CNTs) is essential for modeling graphene and CNT-based nanoelectromechanical systems. This work proposes a new continuum contact model to study interlayer interactions between curved graphene sheets. The continuum model is calibrated and validated using molecular dynamics (MD) simulations. These are carried out employing the reactive...
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Facilitated water transport in composite reduced graphene oxide pervaporation membranes for ethanol upgrading
PublikacjaHigh purity ethanol is one of the most sought-after renewable energy sources. However, standard production methods yield ethanol of insufficient quality. Membrane processes such as pervaporation are recognized as a viable method for upgrading ethanol. Their performance and selectivity depend solely on membrane employed. Hydrophilic polyvinyl alcohol (PVA) membranes are used industrially for this purpose, but there is a trade-off...
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Electrochemical simulation of enzymatic transformations studied for the selected antitumor acridine derivatives
PublikacjaThe elucidation of the metabolic pathways and the biotransformation mechanisms of potential drugs is a crucial point in drug development. It allows to know the activation routes of the new biologically active compounds, especially in respect to their possible toxicity. Generally, in vivo or in vitro experiments with liver microsomes or hepatocytes are performed. However, these testing schemes are tedious, time consuming and of...
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Investigations on the immunosuppressive activity of derivatives of mycophenolic acid in immature dendritic cell
PublikacjaThe main activity of mycophenolic acid (MPA) and its analogs is the inhibition of proliferation of T cells. Here, we hypothesized that MPA and its conjugates inhibits also the activity of antigen-presenting cells (APC) including dendritic cells (DCs). We tested the effect of novel amino acid derivatives of MPA and conjugates of MPA with acridines/acridones on DCs by flow cytometry, ELISA and MLR assay. Both acridines/acridone derivatives...
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Amine–alkyl derivatives of hydantoin: New tool to combat resistant bacteria
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Azomacrocyclic derivatives of imidazole: synthesis, structure, and metal ion complexation properties
PublikacjaNew azocrown ethers comprising imidazoles in the macrocycle have been synthesized. Imidazole, 2-methyl-, 4-methyl-, and 4-phenylimidazole were incorporated to form macrocyclic units by coupling with the appropriate bis-diazonium salts. The syntheseswere performed under high dilution conditions. The X-ray structure of a water adduct of the 21-membered crown ether derivative of 4-methylimidazole 8 has been solved. Metal...
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Antimicrobial activity of 5-arylidene aromatic derivatives of hydantoin. Part 2
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Kinetics of Flavoenzyme-Catalyzed Reduction of Tirapazamine Derivatives: Implications for Their Prooxidant Cytotoxicity
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Determination of the Stereostructure of Pyrimidine Nucleoside Derivatives with a Combination of Various Chiroptical Methods
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Anti-Helicobacter pylori activity of some newly synthesized derivatives of xanthone
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