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Wyniki wyszukiwania dla: electron paramagnetic resonance
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Isolation and structure of a covalent cross-link adduct between mitomycin C and DNA
PublikacjaA DNA cross-link adduct of the antitumor agent mitomycin C (MC) to DNA has been isolated and characterized; the results provide direct proof for bifunctional alkylation of DNA by MC. Exposure of MC to Micrococcus luteus DNA under reductive conditions and subsequent nuclease digestion yielded adducts formed between MC and deoxyguanosine residues. In addition to the two known monoadducts, a bisadduct was obtained. Reductive MC activation...
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Multimodal analysis of traction forces and the temperature dynamics of living cells with a diamond-embedded substrate
PublikacjaCells and tissues are constantly exposed to chemical and physical signals that regulate physiological and pathological processes. This study explores the integration of two biophysical methods: traction force microscopy (TFM) and optically detected magnetic resonance (ODMR) to concurrently assess cellular traction forces and the local relative temperature. We present a novel elastic substrate with embedded nitrogen-vacancy microdiamonds...
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Refined theoretical study of radiative association: Cross sections and rate constants for the formation of SiN
PublikacjaRadiative association of silicon mononitride (SiN) in its two lowest molecular electronic states is studied through quantum and classical dynamics. Special attention is paid to the behavior of the cross section at high collision energies. A modified expression for the semiclassical cross section is presented which excludes transitions to continuum states. This gives improved agreement with quantum mechanical perturbation theory...
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A coarse‐grained approach to NMR ‐data‐assisted modeling of protein structures
PublikacjaThe ESCASA algorithm for analytical estimation of proton positions from coarse-grained geometry developed in our recent work has been implemented in modeling protein structures with the highly coarse-grained UNRES model of polypeptide chains (two sites per residue) and nuclear magnetic resonance (NMR) data. A penalty function with the shape of intersecting gorges was applied to treat ambiguous distance restraints, which automatically...
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Synthesis, characterization, and application of 2D/2D TiO2-GO-ZnFe2O4 obtained by the fluorine-free lyophilization method for solar light-driven photocatalytic degradation of ibuprofen
PublikacjaIn this study, we report the potential of 2D/2D TiO2- GO-ZnFe2O4 photocatalyst obtained using the fluorine-free lyophilization technique for the degradation of ibuprofen belonging to the group of active pharmaceutical ingredients (API). The improved ibuprofen degradation under simulated solar light was achieved in the presence of a composite of 2D TiO2 combined with GO and embedded ZnFe2O4, which additionally provides superparamagnetic...
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Special techniques and future perspectives: Simultaneous macro- and micro-electrode recordings
PublikacjaThere are many approaches to studying the inner workings of the brain and its highly interconnected circuits. One can look at the global activity in different brain structures using non-invasive technologies like positron emission tomography (PET) or functional magnetic resonance imaging (fMRI), which measure physiological changes, e.g. in the glucose uptake or blood flow. These can be very effectively used to localize active patches...
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LC-MS and LC-NMR as Complementary Techniques for the Determination of Pharmaceuticals in Dosage Formulations
PublikacjaPharmaceuticals contain not only pharmacologically active compounds but also a range of excipients. The danger exists that impurities may also be present in such drugs, which may adversely affect their efficacy and even endanger patient health and life. Monitoring the composition of pharmaceutical products is therefore essential. The trace amounts of such impurities in pharmaceuticals are often identified and determined with liquid...
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Induced-fit binding of laccase to gold and carbon electrodes for the biological fuel cell applications
PublikacjaAnalogues of laccase natural substrates (syringic, veratric, ferulic, vanillic, isovanillic, 3,5-dimethoxybenzoic aldehydes) were employed to bind and orient laccase molecules in a way which facilitates adsorption of the catalyst molecules and their electrical connection with the conductive support. Laccase was bound efficiently to these substrates both on gold and carbon electrodes forming, respectively, 2D and 3D films sensitive...
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New method to monitor changes in the subarachnoid width and pial artery pulsation for physiological and clinical research
PublikacjaThere are several medical conditions associated with brain oedema such as traumatic brain injury, intoxication or tumors. Brain edema and related brain parenchyma expansion may lead to compression and subsequent injury of several brain structures. So far, the only method enabling detection and monitoring of the progress a cerebral oedema in a patient, has been monitoring of intracranial pressure (ICP) with a pressure probe inserted...
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Epoxy Composites Filled with Natural Calcium Carbonate. 1. Epoxy Composites Obtained in the Presence of Monoperoxy Derivative of Epidian-6 Epoxy Resin
PublikacjaPhysico-mechanical properties of the products based on filled epoxy-oligomeric mixtures composed of Epidian-5 epoxy resin, oligoesteracrylate TGM-3 and monoperoxide derivative of Epidian-6 epoxy resin (PO) have been investigated. CaCO3 was used as a filler and polyethylene polyamine was a curing agent. The effect of PO and CaCO3 on the gel-fraction content and physico-mechanical properties was examined. Using a scanning electron...
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THE USE OF THE Ti-13Zr-13Nb ALLOY POWDER FOR MANUFACTURING OF PROSTHETIC PARTS BY SELECTIVE LASER MELTING
PublikacjaThe 3D printing is a manufacturing technique belonging to the additive methods able to prepare the designed parts for various purposes. The present reasearch was aimed to fabricate the prosthetic foundations and bridges made of the new Ti-13Zr-13Nb alloy by the selective laser melting (SLM) of a metal powder. The scanning electron examinations and micro scanning tomography were used to investigate the surface quality and intrinsic...
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The rovibrational energy levels of the diatomic silver anion and neutral silver dimer
Dane BadawczeThe process of a two-channel decay of the diatomic silver anion (Ag2-), namely the spontaneous electron ejection giving Ag2 + e- and the dissociation leading to Ag- + Ag is theoretically studied. The ground state potential energy curves (PECs) of the neutral silver dimer and anionic silver diatomic molecule are calculated using the single reference...
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Diamond surface modification following thermal etching of Si supported hydrogenated diamond films by DBr
PublikacjaZbadano, wykorzystując spektroskopię oscylacyjną (HREELS - High Resolution Electron Energy Loss Spectroscopy) modyfikacje chemiczne powierzchni wodorowanego diamentu, umieszczonego na podkładzie krzemowym i wystawionego na działanie DBr a następnie podgrzanego do temp. powyżej 600 st.K. Przedstawiona procedura powoduje tworzenie się węglika krzemu SiC na powierzchni warstwy diamentowej, co jest widoczne na widmie HREEL jako dwa...
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Formation of intermetallic compounds in the solid-liquid composites of the Ga-Ni system
PublikacjaThe processes of formation of intermetallic compounds in the composite system of liquid gallium-nickel powder by the methods of x-ray diffraction, scanning electron microscopy and differential thermal analysis have been studied. A change in the phase composition was discovered and the influence of thermal treatment of the composites under investigation on the phase formation processes was analyzed. The mechanism of gallium enriched...
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Nongeminate recombination in organic bulk heterojunction solar cells: Contribution of exciton–polaron interaction
PublikacjaA new model to explain nongeminate recombination in organic bulk heterojunction solar cells is presented. We suggest that the annihilation of excitons on charge carriers at the interface between donor and acceptor phases competes with the bimolecular recombination of Coulombically bound electron–hole pairs. The exciton–polaron interaction gives visible contribution to the reduction of Langevin recombination. An analytical formula,...
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Hybrid biobateryy based on arylated carbon nanotubes and laccase
PublikacjaSingle-walled carbon nanotubes (SWCNT) were covalently modified with antracene and antraquinone and used for the construction of cathodes for biocatalytic reduction od dioxygen. The nanotubes with aromatic groups casted onto the electrode increased the working surface of the electrode and enabled efficient direct electron tarnsfer (DET) between the enzyme and the electrode. the aryl groups enter the hydrophobic pocket of the T1...
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TEM and EDX study of the Al2O3 ultra thin films
Dane BadawczeThe ultra-thin layers of Al2O3 were deposited on a silicon substrates. The method of atomic layer deposition (Beneq TFS 200 ALD system) was chosen as the proper method of dielectric layer deposition. This method provides precise thickness control down to a single atomic layer. The precursors used were trimethylaluminum (Sigma-Aldrich) and purified water....
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Influence of the annealing condictions on the chemical structure of LaBaGdCo ceramics
Dane BadawczeCeramic samples based on Barium, Lanthanum, Gadolinium and Cobaltium were produced by solid state reaction. After sintring in a furnance, samples were annealed at 300 Celsius degree in wet and dry atmosphere. Annealing takes 72h or 2h. Results of annealing were observed by X-Ray photoemission spectroscopy (XPS), OmicronNanotechnology. XPS analysis...
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Diaryl Sulfide Derivatives as Potential Iron Corrosion Inhibitors: A Computational Study
PublikacjaThe 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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Experimental and theoretical investigation of conformational states and noncovalent interactions in crystalline sulfonamides with a methoxyphenyl moiety
PublikacjaFour sulfonamide derivatives with a methoxyphenyl moiety, namely N-{4-[(2-methoxyphenyl)sulfamoyl] phenyl}acetamide (1a), N-{4-[(3-methoxyphenyl)sulfamoyl]phenyl}acetamide (1b), 4-amino-N-(2- methoxyphenyl)benzenesulfonamide (2a) and 4-amino-N-(3-methoxyphenyl)benzenesulfonamide (2b), have been synthesized and characterized physiochemically by CHNS, MS, FT-IR, 1H NMR, 13C NMR, PXRD and TG methods. Crystal structures were determined...
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Comparison of Properties of the Hybrid and Bilayer MWCNTs—Hydroxyapatite Coatings on Ti Alloy
PublikacjaCarbon nanotubes are proposed for reinforcement of the hydroxyapatite coatings to improve their adhesion, resistance to mechanical loads, biocompatibility, bioactivity, corrosion resistance, and antibacterial protection. So far, research has shown that all these properties are highly susceptible to the composition and microstructure of coatings. The present research is aimed at studies of multi-wall carbon nanotubes in three different...
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The Influence of the Electrodeposition Parameters on the Properties of Mn-Co-Based Nanofilms as Anode Materials for Alkaline Electrolysers
PublikacjaIn this work, the influence of the synthesis conditions on the structure, morphology, and electrocatalytic performance for the oxygen evolution reaction (OER) of Mn-Co-based films is studied. For this purpose, Mn-Co nanofilm is electrochemically synthesised in a one-step process on nickel foam in the presence of metal nitrates without any additives. The possible mechanism of the synthesis is proposed. The morphology and structure...
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Various types of semiconductor photocatalysts modified by CdTe QDs and Pt NPs for toluene photooxidation in the gas phase under visible light
PublikacjaA novel synthesis process was used to prepare TiO2 microspheres, TiO2 P-25, SrTiO3 and KTaO3 decorated by CdTe QDs and/or Pt NPs. The effect of semiconductor matrix, presence of CdTe QDs and/or Pt NPs on the semiconductor surface as well as deposition technique of Pt NPs (photodeposition or radiolysis) on the photocatalytic activity were investigated. The as-prepared samples were characterized by X-ray powder diffractometry (XRD),...
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Singlet oxygen-dominated peroxymonosulfate activation by layered crednerite for organic pollutants degradation in high salinity wastewater
PublikacjaAdvanced oxidation processes have been widely studied for organic pollutants treatment in water, but the degradation performance of radical-dominated pathway was severely inhibited by the side reactions between the anions and radicals, especially in high salinity conditions. Here, a singlet oxygen (1O2)-dominated non-radical process was developed for organic pollutants degradation in high salinity wastewater, with layered crednerite...
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Screen-printed Sn-doped TiO2 nanoparticles for photocatalytic dye removal from wastewater: A technological perspective
PublikacjaTiO2 is widely used as a photocatalyst with a wide band gap, which limited its application. Ion doping and formulating a high-quality screen-printing paste enhance its features. However, the printability of objects for advanced application seems essential nowadays. In this research, the Sn-doped TiO2 nanoparticles were prepared through a sol-gel method followed by calcination at various temperatures of 450 °C, 550 °C, 650 °C, 750...
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Shaking table experimental study on the effectiveness of polymer bearings for seismic isolation of structures
PublikacjaSeismic isolation has been recognised to be a very effective way of protecting structures from damage during earthquakes. It allows us to extend the natural period of the structure and therefore avoid resonance with the ground motion. Moreover, by increasing damping in the isolation devices, more energy can be dissipated and thus the structural response can be further reduced. The aim of this paper is to show the results of the...
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Innovative Bidirectional Isolated High-Power Density On-Board Charge for Vehicle-to-Grid
PublikacjaThis paper deals with developing and implementing a bidirectional galvanically isolated on-board charger of a high-power density. The power density of the new charger was 4 kW/kg and 2.46 kW/dm3, and the maximum efficiency was 96.4% at 3.4 kW. Due to the requirement to achieve a high-power density, a single-stage inverter topology was used. Regarding switching losses, due to the topology of the circuit with so-called hard switching,...
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Phosphinophosphoranes: Mixed-Valent Phosphorus Compounds with Ambiphilic Properties
PublikacjaHerein, we present a simple synthesis of mixed-valent phosphinophosphoranes bearing three- and five-coordinate phosphorus centers. Compounds with phosphorus–phosphorus bonds were synthesized via a reaction of lithium phosphides RR′PLi with cat2PCl (cat = catecholate), whereas derivatives with methylene-linked phosphorus centers were obtained via a reaction of phosphanylmethanides RR′CH2Li with cat2PCl. The presence of accessible...
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Eco-Friendly Ether and Ester-Urethane Prepolymer: Structure, Processing and Properties
PublikacjaThis study concerns bio-based urethane prepolymers. The relationship between the chemical structure and the thermal and processing parameters of bio-based isocyanate-terminated ether and ester-urethane prepolymers was investigated. Bio-based prepolymers were obtained with the use of bio-monomers such as bio-based diisocyanate, bio-based polyether polyol or polyester polyols. In addition to their composition, the bio-based prepolymers...
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Principles of target DNA cleavage and the role of Mg2+ in the catalysis of CRISPR–Cas9
PublikacjaAt the core of the CRISPR–Cas9 genome-editing technology, the endonuclease Cas9 introduces site-specific breaks in DNA. However, precise mechanistic information to ameliorate Cas9 function is still missing. Here, multimicrosecond molecular dynamics, free energy and multiscale simulations are combined with solution NMR and DNA cleavage experiments to resolve the catalytic mechanism of target DNA cleavage. We show that the conformation...
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Plasma-Based Deposition and Processing Techniques for Optical Fiber Sensing
PublikacjaPlasma-based techniques are widely applied for well-controlled deposition, etching or surface functionalization of a number of materials. It is difficult to imagine fabrication of novel microelectronic and optoelectronic devices without using plasma-enhanced deposition of thin films, their selective etching or functionalization of their surfaces for subsequent selective binding of chemical or biological molecules. Depending on...
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Experimental study on the effectiveness of polymer damper in damage reduction of temporary steel grandstand
PublikacjaA large number of accidents, involving collapses of temporary grandstands during different types of events, were observed in the past. If the synchronized movement of people is tuned with the natural frequency of the affected part of the structure, resonance might occur. It may lead to severe damages of grandstands, their collapse or panic among the spectators. The aim of the paper is to assess, through preliminary experimental...
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The topography of strontium–borate glasses and glass-ceramics containing bismuth and vanadium oxides measured with SEM method
Dane BadawczeThe topography of strontium–borate glasses and glass-ceramics containing bismuth and vanadium oxides was measured by SEM.
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Cavitation wearing of the SUPERSTON alloy after laser treatment at cryogenic conditions
PublikacjaThe purpose of this paper is to demonstrate the method of laser remelting at cryogenic conditions of the SUPERSTON alloy and its influence on microstructure and cavitation wearing. The cavitation test was performed using the rotating disc facility in IPM PAN Gdansk. During the cavitation test, the mass loss of the material with different parameters of laser remelting was determined. Surface and cross-section microstructure of the...
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Superconductivity in Bismuth Pyrochlore Lattice Compounds RbBi2 and CsBi2: The Role of Relativistic Effects
PublikacjaSuperconducting properties of two bismuthide intermetallic compounds, RbBi2 and CsBi2, were studied by means of experimental measurements and ab initio calculations. We show that in both compounds, the superconductivity emerges from the pyrochlore Bi lattice and its formation is heavily influenced by relativistic effects. Based on our analysis of the effect of spin–orbit coupling on the electron–phonon coupling, we suggest a possible...
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Investigation of corrosion behavior of 6060 and 6082 aluminum alloys under simulated acid rain conditions
PublikacjaInstantaneous impedance changes of 6060 and 6082 type aluminum alloys in pure water, and simulated acid rain poured into the pure water was investigated by dynamic electrochemical impedance spectroscopy (DEIS). In this way, the influence of aluminum content on the corrosion behavior of 6060 and 6082 type aluminum alloys immersed in simulated acid rain was determined. The corrosion rate of the alloy decreased with increasing Al...
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Cytotoxic and Antioxidant Activities of Benzohydroxamic Acid Analogues
Publikacja20 benzohydroxamic acid analogues were synthesized and evaluated for their in vitro cytotoxicities against mouse mammary tumor cells as well as antioxidant activities against DPPH radical and superoxide anion. It was found that benzothiohydroxamic acids exhibit greater cytotoxicities than benzohydroxamic acids and N-isopropyl derivatives are more active than N-methyl ones. On the other hand, benzothiohydroxamic acids show more...
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Interactions between components of SrTi0.98 Nb0.02O3-δ-YSZ and SrTi0.98 Nb0.02O3-δ -CeO2 composites
PublikacjaComposites consisting of SrTiO3-based perovskite and either yttria-stabilized zirconia or ceria were investigated. The mechanical compatibility and possible inter-diffusion between phases were characterized by scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. A gradual disappearance of Ce-containing phases with an increase in the temperature of reduction in hydrogen was noticed. Moreover,...
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Sharp transitions in low-number quantum dots Bayesian magnetometry
PublikacjaWe consider Bayesian estimate of static magnetic field, characterized by a prior Gaussian probability distribution, in systems of a few electron quantum dot spins interacting with infinite temperature spin environment via hyperfine interaction. Sudden transitions among optimal states and measurements are observed. Usefulness of measuring occupation levels is shown for all times of the evolution, together with the role of entanglement...
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A Method and Device for 3D Recognition of Cutting Edge Micro Geometry
PublikacjaA very useful method was successfully applied in the investigation of tools for machining wood and wood based composites. It allows scanning of the cutting edge micro geometry in three dimensions and reproducing it in a virtual space as a 3D surface. The application of the method opens new possibilities of studying tool wear by scanning, including the calculation of volume loss and other analysis of tool wedge geometry along and...
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Electrical conductivity and relaxation processes in V2O5 nanorods prepared by sol–gel method
PublikacjaProperties of high purity V2O5 nanorods prepared by a sol – gel method are presented. The studied materials were characterized by: X-ray diffractometry (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The electrical impedance was measured as a function of temperature and frequency. The obtained results show that the electrical conductivity increases with increasing temperature. The d.c. conductivity...
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Instantaneous impedance monitoring of AA 7075 aluminum alloy corrosion in borate buffer with admixed chloride ions
PublikacjaThe study presents a research capabilities of Dynamic Electrochemical Impedance Spectroscopy (DEIS) as a tool used for instantaneous on-line monitoring of corrosion processes on the example of AA 7075 aluminum alloy. A borate buffer with admixed chloride ions in a quantity ranging from 0.05 to 25 mM was used to represent different types of corrosion attack. The surface of samples specimens was evaluated before and after the tests...
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Structural, magnetic and spectral properties of tetrahedral cobalt(II) silanethiolates: a variety of structures and manifestation of field-induced slow magnetic relaxation
PublikacjaBlue crystals of five heteroleptic cobalt(II) silanethiolates 1–5 have been obtained by the reaction of [Co{SSi (tBuO)3}2(NH3)]2 with aminopyridines and aminomethylpyridines at an appropriate molar ratio and their structural, spectral, thermal and magnetic properties have been established and described. All complexes 1–5 contain Co(II) ions in a tetrahedral CoN2S2 environment formed by (tBuO)3SiS− residues and pyridines and present...
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Effect of carbazole and pyrrolidine functionalization of phenanthroline ligand on ground- and excited-state properties of rhenium(I) complexes. Interplay between 3MLCT and 3IL/3ILCT
PublikacjaNew rhenium(I) tricarbonyl complexes based on the phenanthroline ligand were designed and synthesized to investigate the role of carbazole (cbz) and pyrrolidine (pyrr) substituents in determining thermal, electrochemical and optoelectronic properties. Both pyrr and cbz are electron-releasing substituents, but they differ in the steric hindrance and electron delocalization ability. The impact of pyrr and cbz on ground- and excited-state...
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Chemically reduced graphene oxide based aerogels - Insight on the surface and textural functionalities dependent on handling the synthesis factors
PublikacjaEfficient adjusting of reduced graphene oxide aerogels properties requires information about experimental factor-aerogel property relationship. In this work, the reduced graphene oxide aerogels surface and textural functionalities in relation to precursor concentration, gelation time and hydrogel freezing temperature were studied in detail, with the use of dynamic adsorption method of gaseous organic probes and experimental design....
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Relationship between GIX, SIDX, and ROTI ionospheric indices and GNSS precise positioning results under geomagnetic storms
PublikacjaIonospheric indices give information about ionospheric perturbations, which may cause absorption, diffraction, refraction, and scattering of radio signals, including those from global navigation satellite systems (GNSS). Therefore, there may be a relationship between index values and GNSS positioning results. A thorough understanding of ionospheric indices and their relationship to positioning results can help monitor and forecast...
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Bias-Dependent Dynamics of Degradation and Recovery in Perovskite Solar Cells
PublikacjaDegradation of perovskite solar cells (PSCs) is often found to be partially or fully reversible when the cells are allowed to recover in the dark. Unlike the dynamics of degradation, knowledge about the dynamics of PSC cell recovery is very limited. Here, we demonstrate that the PSC recovery strongly depends on the electrical bias conditions during the light-induced degradation and that it can be manipulated by applying an external...
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Scattering of electrons by a 1,2-butadiene (C4H6) molecule: measurements and calculations
PublikacjaWe present the results of experimental and theoretical study on electron collisions with a 1,2-butadiene (H2C=C=CHCH3) molecule. Absolute grand-total cross sections (TCSs) were measured using a linear electron-transmission method for collision energies in the 0.5–300 eV range. Two distinct features in the TCS energy curve were detected: a narrow peak located at 2.3 eV and a broad enhancement centered around 9 eV. We attributed...
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Perovskite-type KTaO3–reduced graphene oxide hybrid with improved visible light photocatalytic activity
PublikacjaNovel rGO–KTaO3 composites with various graphene content were successfully synthesized using a facile solvothermal method which allowed both the reduction of graphene oxide and loading of KTaO3 nanocubes on the graphene sheets. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX), Fourier...
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The influence of small intestinal mucus structure on particle transport ex vivo
PublikacjaMucus provides a barrier to bacteria and toxins while allowing nutrient absorption and waste transport. Unlike colonic mucus, small intestinal mucus structure is poorly understood. This study aimed to provide evidence for a continuous, structured mucus layer and assess the diffusion of different sized particles through it. Mucus structure was assessed by histology and immunohistochemistry. Ultra-structure was assessed by scanning...