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Wyniki wyszukiwania dla: MOLECULAR SPECTROSCOPY
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Characterization of a single-stranded DNA-binding-like Protein from Nanoarchaeum equitans - a nucleic acid binding protein with broad substrate specificity
PublikacjaBackground SSB (single-stranded DNA-binding) proteins play an essential role in all living cells and viruses, as they are involved in processes connected with ssDNA metabolism. There has recently been an increasing interest in SSBs, since they can be applied in molecular biology techniques and analytical methods. Nanoarchaeum equitans, the only known representative of Archaea phylum Nanoarchaeota, is a hyperthermophilic, nanosized,...
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Effect of bio-based components on the chemical structure, thermal stability and mechanical properties of green thermoplastic polyurethane elastomers
PublikacjaIt seems to be obvious that conditions changes during polyols synthesis have impact on the polyols properties. Even the chemical formula is the same or similar, physicochemical properties and also molecular weight of polyols might be different and are significant in term of future polyurethanes properties and processing. In this work, fully bio-based poly(propylene succinate)s synthesized at different temperature conditions were...
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Analysis of the Possibility of Using New Types of Protective Coatings and Abrasion-Resistant Linings under the Operating Conditions of the Spiral Classifier at KGHM Polska Miedź S.A. Ore Concentration Plant
PublikacjaA study was carried out to select the appropriate coatings for corrosion protection of the spiral classifier working at KGHM Polska Miedź S.A. Ore Concentration Plant. The abrasion resistance of selected protective coatings and wear-resistant linings was investigated using a DT-523 rotary abrasion tester with Taber CS-10 rubber abrasive discs. The average weight loss of the coatings after a cycle of 2000 revolutions was determined....
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Stabilization of N-, N,N-, N,N'-Methylated and Unsubstituted Simple Amidine Salts by Multifurcated Hydrogen Bonds
PublikacjaIn the light of the usefulness of amidines in medicinal chem., this paper considers the effects on biol. properties and chem. reactivities of org. mols. affected by intramol. interactions. The study of chem. shifts has been an important source of information on the electronic structure of amidine salts and their ability to form non-covalent bonds with nucleic acids. The NMR and IR results demonstrate that hydrogen bonds are...
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Application of polyethylene glycol-coated iron oxide nanoparticles for magnetic solid phase extraction of copper from seawater samples and its determination by graphite furnace atomic absorption spectrometry using response surface methodology for optimization of extraction
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Chemometric determination of solute-affected solvent vibrational spectra as a superior way of information extraction on solute solvation phenomena
PublikacjaW pracy zaprezentowano dwie chemometryczne metody wyznaczania widm zaburzonych rozpuszczalnika oraz liczby cząsteczek zaburzonych, na podstawie zmierzonych serii wibracyjnych widm FT-IR roztworów substancji. Pierwsza z metod została stworzona na podstawie Namiarowej Analizy Faktorowej (ang. Target Factor Analysis). Druga z nich wykorzystuje algorytm izolacji widm czystych składników z serii widm mieszanin. Działanie obu metod zostało...
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Chemometric Method of Spectra Analysis Leading to Isolation of Lysozyme and CtDNA Spectra Affected by Osmolytes
PublikacjaW niniejszej pracy zaprezentowana została chemometryczna metoda analizy danych widmowych, prowadząca do wyizolowania widm FTIR biomakrocząsteczek (lizozymu z białka jaja kurzego i ctDNA) zaburzonych przez wybrane osmolity (TMAO, betainę) w roztworach wodnych. Została ona oparta na metodzie widm różnicowych, wykorzystywanej pierwotnie do określania struktury rozpuszczalnika wokół cząsteczek substancji rozpuszczonej. Cykliczne wykorzystanie...
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Polyurethane Nanocomposites Containing Reduced Graphene Oxide, FTIR, Raman, and XRD Studies
PublikacjaRecently, graphene and other graphene-based materials have become an essential part of composite science and technology. Their unique properties are not only restricted to graphene but also shared with derivative compounds like graphene oxide, reduced graphene oxide, functionalized graphene, and so forth. One of the most structurally important materials, graphene oxide (GO), is prepared by the oxidation of graphite. Though removal...
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Role of nitrogen in evolution of sp2/sp3 bonding and optical band gap in hydrogenated carbon nitride
PublikacjaDrastic changes in the bonding are found in amorphous hydrogenated carbon nitride (a-CNx:H) film as a function of nitrogen concentration (or N/C ratio). The total C-sp3 fraction and hardness shows a sharp decrease (at N/C = 0.40) whereas optical band gap and resistivity shows a gradual increase as nitrogen concentration increases from 0.07 to 0.58. Raman spectrum of a-CNx:H film is fitted with both Gaussian (integrated intensity...
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Electron Density from Balmer Series Hydrogen Lines and Ionization Temperatures in Inductively Coupled Argon Plasma Supplied by Aerosol and Volatile Species
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Nonradiative excitation energy transport and its analysis in concentrated systems
PublikacjaW pracy przedstawiono analizę transportu energii w roztworach dwuskładnikowych. Porównano wyniki pomiarów z modelem hoppingowym i diagramatycznym oraz z wynikami symulacji Monte Carlo. Stwierdzono dobrą zgodność wyników eksperymentalnych z przewidywaniami teorii i symulacjami komputerowymi.
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Raman investigation of the patina layers on Hungarian copper ingots from a fifteenth century shipwreck
PublikacjaWe report results of the patina study of underwater archeological finding ofmedieval copper objects performed by means of the Raman and complementary spectroscopic techniques. The objects were found submerged in the sea as cargo part of the ship which sunk in the Gulf of Gdańsk in 1408. The excavated collection consists of 230 oval ingots of the size and mass up to about 60 cm and 18 kg (total of 2 tons), respectively. In the Raman...
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Novel decahedral TiO2 photocatalysts modified with Ru or Rh NPs: Insight into the mechanism
PublikacjaNovel decahedral TiO2 modified with Ru or Rh NPs were successfully synthesized by hydrothermal method. The effect of metal type as well as amount of noble metal precursor (0.05, 0.1, 0.2, 0.3 and 0.5 wt.%) on the photocatalytic activity were investigated. Decahedral TiO2 decorated by Ru and Rh nanoparticles was prepared by photodeposition method, whereas Rh doped TiO2 was obtained by onestep hydrothermal method with introduction...
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Quantitative fluorescent determination of DNA – Ochratoxin a interactions supported by nitrogen-vacancy rich nanodiamonds
PublikacjaOchratoxin A (OTA) is a hazardous contaminant of a large variety of plant and animal originated food. Herein, we report an interaction of OTA with calf thymus DNA (ct DNA) on the nanodiamond surface. We employed multispectroscopic techniques to elucidate the binding mechanism of OTA with ct DNA. The fluorescence and UV–Vis spectroscopy results show that OTA binds to ds ct DNA and forms complexes. We obtained the binding constants...
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New nanoadsorbent based on magnetic iron oxide containing 1,4,7,10-tetraazacyclododecane in outer chain (Fe3O4@SiO2-cyclen) for adsorption and removal of selected heavy metal ions Cd2+, Pb2+, Cu2+
PublikacjaMagnetic Fe3O4@SiO2-cyclen nanoparticles were prepared and used as adsorbent for Cd2+, Pb2+ and Cu2+ from aqueous solution removal process controlled with differential pulse anodic stripping voltammetry (DPASV) and hanging mercury drop electrode (HDME). Nanomaterial was synthesised in three-step process co-precipitation of Fe3O4 core, coating with silane and N-(3-(triethoxysilyl)propyl)-1,4,7,10-tetraazacyclododecane-1-carboxamide...
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Influence of Urea and Dimethyl Sulfoxide on K-Peptide Fibrillation
PublikacjaProtein fibrillation leads to formation of amyloids—linear aggregates that are hallmarks of many serious diseases, including Alzheimer’s and Parkinson’s diseases. In this work, we investigate the fibrillation of a short peptide (K-peptide) from the amyloidogenic core of hen egg white lysozyme in the presence of dimethyl sulfoxide or urea. During the studies, a variety of spectroscopic methods were used: fluorescence spectroscopy...
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Conductivity and viscosity changes of imidazolium ionic liquids induced by H2O and CO2
PublikacjaSeveral solutions of ionic liquids based on 1-ethyl-3-methylimidazolium cation saturated and unsaturated with carbon dioxide were prepared and characterized by electrochemical impedance spectroscopy. The in fluence of ILs saturation on its electrical conductivity was determined. Additionally, the in fluence of the water presence and variations of temperature on electrical properties of ionic liquids were investigated. Changes of...
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Physicochemical and Volatile Compounds Analysis of Fruit Wines Fermented with Saccharomyces cerevisiae: FTIR and Microscopy Study with Focus on Anti-Inflammatory Potential
PublikacjaThe growing trend in fruit wine production reflects consumers’ interest in novel, diverse drinking experiences and the increasing demand for healthier beverage options. Fruit wines made from kiwi, pomegranates, and persimmons fermented using S. bayanus Lalvin strain EC1118 demonstrate the versatility of winemaking techniques. Kiwifruit, persimmon, and pomegranate wines were analyzed using HPLC and GC-TOFMS analyses to determine...
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Recent Developments in Data-Assisted Modeling of Flexible Proteins
PublikacjaMany proteins can fold into well-defined conformations. However, intrinsically-disordered proteins (IDPs) do not possess a defined structure. Moreover, folded multi-domain proteins often digress into alternative conformations. Collectively, the conformational dynamics enables these proteins to fulfill specific functions. Thus, most experimental observables are averaged over the conformations that constitute an ensemble. In this...
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Arbutin: Isolation, X-ray structure and computional studies
PublikacjaArbutin, an active component originated from Serratula quinquefolia for skin-whitening use and treating skin related allergic inflammation, was characterized by microanalysis, FTIR, UV-Vis, multinuclear NMR spectroscopy, and single crystal X-ray diffraction method. The geometries of the studied compound were optimized in singlet states using the density functional theory (DFT) method with B3LYP functional. Electronic spectra were...
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Copper-based 2D-coordination polymer as catalyst for allylation of aldehydes
PublikacjaA copper-tartrate, [Cu2(Tart)2(H2O)2]·4H2O, was synthesized at room temperature in aqueous media using copper chloride and D-tartaric acid. The compound crystallizes in the monoclinic system P21 space group and was characterized by infrared spectroscopy, thermogravimetry, X-ray powder diffraction and the results are in good agreement with the single crystal...
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Hybrid cross-linked chitosan/protonated-proline:glucose DES membranes with superior pervaporation performance for ethanol dehydration
PublikacjaThis work explores a protonated L-proline:glucose (molar ratio 5:1) deep eutectic solvent (DES) in fabricating biopolymer membranes utilizing chitosan (CS). Initially, the miscibility of CS and DES to prepare homogeneous dense blend membranes has been investigated. Different techniques, such as scanning electron microscopy, contact angle (CA), atomic force microscopy (AFM), Fourier transformed infrared spectroscopy (FTIR) and swelling...
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Mono- and polynuclear Co(II) silanethiolates with aliphatic diamines
PublikacjaFour Co(II) complexes, [Co{SSi(OtBu)3}2(dmpda)] 1, [Co{SSi(OtBu)3}2(bda)2]n2 [Co{SSi(OtBu)3}2(pda)2]n3 and [Co{SSi(OtBu)3}2(hda)2]n4 [dmpda = 3-(dimethylamino)-1-propylamine; bda = 1.4-butanediamine; pda = 1.5-pentanediamine; had = 1.6-hexanediamine] have been synthesized and characterized using X-ray diffraction. Complex 1 is mononuclear and contains Co(II) coordinated by dmpda molecule in chelating mode, whereas compounds 3 and...
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Aqueous solutions of NMA, Na2HPO4 , and NaH2PO4 as models for interaction studies in phosphate–protein systems
PublikacjaPhosphate buffers are essential for many areas of studies. However, their influence on buffered systems is often ignored. The phosphate salts can interact with biologically important macromolecules (e.g. proteins) and stabilize or destabilize them. With our research, we want to answer question what kind of interactions, if any, occur between phosphate ions and a protein backbone model — N-methylacetamide (NMA). ATR-FTIR spectroscopy...
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Improvements and new functionalities of UNRES server for coarse-grained modeling of protein structure, dynamics, and interactions
PublikacjaIn this paper we report the improvements and extensions of the UNRES server (https://unres-server.chem.ug.edu.pl) for physics-based simulations with the coarse-grained UNRES model of polypeptide chains. The improvements include the replacement of the old code with the recently optimized one and adding the recent scale-consistent variant of the UNRES force field, which performs better in the modeling of proteins with the β and the...
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Interactions between hydration spheres of two different solutes in solution: The least squares fitting with constraints as a tool to determine water properties in ternary systems
PublikacjaBiological systems are complex and the problem of their description lies in mutual interactions between their components. This paper is focused on model experiment-based studies which can reduce these difficulties. The ternary aqueous N-methylacetamide (NMA)–Na2HPO4 system has been studied by means of the FTIR spectroscopy. A novel difference spectra method aimed to extract the spectral contribution of water affected simultaneously...
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Development of Biocompatible Fe3O4@SiO2 Nanoparticles as Subcellular Delivery Platform for Glucosamine-6-phosphate Synthase Inhibitors
PublikacjaNumerous inhibitors of glucoseamine-6-phophate synthase (GlcN-6-P), the enzyme responsible from catalysis of the first step of metabolic pathway leading to metabolism 5’-diphospho-N-acetyl-D- glucosamine, were reported as effective agents for inhibiting the growth of various fungal pathogens. Among the reported inhibitors,...
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The electronic excited states of dichloromethane in the 5.8-10.8 eV energy range investigated by experimental and theoretical methods
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Theoretical interpretations of photoelectron spectra of platinum atom, its cation and anion
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Theoretical interpretation of photoelectron spectra of the iridium neutral atom and anion
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Precise x-ray energies of gadolinium determined by a combined experimental and theoretical approach
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Photoelectron spectroscopy of a series of acetate and propionate esters
PublikacjaThe electronic state and photoionization spectroscopy of a series of acetate esters: methyl acetate, isopropyl acetate, butyl acetate and pentyl acetate as well as two propionates: methyl propionate and ethyl propionate, have been determined using vacuum-ultraviolet photoelectron spectroscopy. These experimental investigations are complemented by ab initio calculations. The measured first adiabatic and vertical ionization energies...
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Cross-sections for electron-scattering from 2-methyl-1-buten-3-yne, C 5 H 6 , molecules
PublikacjatCross-sections for electron collisions with the 2-methyl-1-buten-3-yne [H2C C(CH3)C CH] moleculewere measured and calculated. Absolute grand-total electron-scattering cross-section (TCS) was takenat impact energies from 0.6 to 300 eV in the linear electron-transmission experiment. The TCS energydependence for the electron–C5H6collision has two prominent enhancements separated with a deepminimum located near 1.8 eV. In addition,...
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Electron energy-loss spectroscopy of excited states of the diazine molecules: Pyridazine
PublikacjaExcitation of the valence electronic states of the pyridazine molecules in the gas phase have been studied using the technique of electron energy-loss spectroscopy. Varying the electron scattering conditions, the residual electron energy and scattering angle, enabled the optically-allowed and -forbidden excitations to be differentiated. The measured energy-loss spectra enabled the vertical excitation energies of the observed states...
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Study of ultraviolet-visible fluorescence emission following resonant Auger decay of the 2p-1nl core-excited states of argon atoms
PublikacjaWe have studied the excitation and relaxation of Ar+ ions populated in resonant Auger decay from the Ar 2p−1nl core-excited states by using ultraviolet-visible fluorescence spectroscopy and photon-photon delayed coincidence technique. Fluorescence emission yields were measured in the photon energy range of 240-–255 eV for the 3s23p4(1D)5s(2D) → 3s23p4(1D)4p(2F) (393 nm) and 3s23p4(1D)4d(2F) → 3s23p4(1D)4p(2F) (335 nm) transitions...
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The electronic excited states of dichloromethane in the 5.8-10.8 eV energy range investigated by experimental and theoretical methods
PublikacjaWe present a comprehensive experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectrum of dichloromethane, CH 2 Cl 2 , with absolute cross sections determined for the full 5.8–10.8 eV energy-range. The calculations on the vertical excitation energies and oscillator strengths were performed using the equation-of-motion coupled cluster method, restricted to the single and double excitations level (EOM-CCSD), and...
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Optimization of the femtosecond laser impulse for excitation and the Spin-Orbit mediated dissociation in the NaRb Dimer
PublikacjaWe study the dynamics of multiple coupled states under the influence of an arbitrary time-dependent external field to investigate the femtosecond laser-driven excitation and the spin-orbit mediated dissociation in the NaRb dimer. In this process, the dimer is excited from the ground triplet state 1^3Sigma+ to the 1^3Pi state using the femtosecond laser impulse and the spin-orbit coupling between the 1^3Pi and 2^1Sigma+ states results...
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Excited states of isoxazole molecules studied by electron energy-loss spectroscopy
PublikacjaElectron energy-loss spectra were measured in isoxazole in the excitation energy range 3.5−10 eV to investigate the valence excited states. Spectra recorded at different scattering conditions enabled the identification of the singlet and triplet states and the determination of their vertical excitation energies. The two lowest energy triplet bands, ππ* 13A' and ππ* 23A' at 4.20 and 5.30 eV, respectively show vibrational progressions....
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Experimental and predicted physicochemical properties of monopropanolamine-based deep eutectic solvents
PublikacjaIn this work, the novel deep eutectic solvents (DESs) based on 3-amino-1-propanol (AP) as hydrogen bond donor (HBD) and tetrabutylammonium bromide (TBAB) or tetrabutylammonium chloride (TBAC) or tetraethylammonium chloride (TEAC) as hydrogen bond acceptors (HBAs) were synthesized with different molar ratios of 1: 4, 1: 6 and 1: 8 salt to AP. Fourier Transform Infrared Spectroscopy measurements were performed to provide an evidence...
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Reactive imines: Addition of 2-aminopyrimidine to the imine bond and isolation of the aminal from the equilibrium mixture aminal/imine
PublikacjaThe reaction between o-vanillin and 2-aminopyrimidine leads to the formation of a single crystalline product: aminal, 1, which results from the reaction of the initially formed imine with 2-aminopyrimidine. The reaction was followed by the NMR spectroscopy. VT NMR studies prove that in solution two major species are observed: aminal and imine and their ratio depends on the time or/and temperature with the imine content increasing...
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Investigation of tetrabutylammonium bromide-glycerol-based deep eutectic solvents and their mixtures with water by spectroscopic techniques
PublikacjaDeep eutectic solvents (DES) are formed by an acceptor and a donor of hydrogen bonds. They are generally considered as a possible alternative to hazardous organic solvents in various fields. Very recently they have also appeared in analytical chemistry, used mainly for the separation of analytes before instrumental quantification. For the development of new extraction procedures, it is important, among other things, to understand...
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Experimental and predicted physicochemical properties of monopropanolamine-based deep eutectic solvents
PublikacjaIn this work, the novel deep eutectic solvents (DESs) based on 3-amino-1-propanol (AP) as hydrogen bond donor (HBD) and tetrabutylammonium bromide (TBAB) or tetrabutylammonium chloride (TBAC) or tetraethylammonium chloride (TEAC) as hydrogen bond acceptors (HBAs) were synthesized with different molar ratios of 1:4, 1:6 and 1:8 salt to AP. Fourier Transform Infrared Spectroscopy measurements were performed to provide an evidence...
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Interactions in Ternary Aqueous Solutions of NMA and Osmolytes—PARAFAC Decomposition of FTIR Spectra Series
PublikacjaIntermolecular interactions in aqueous solutions are crucial for virtually all processes in living cells. ATR-FTIR spectroscopy is a technique that allows changes caused by many types of such interactions to be registered; however, binary solutions are sometimes difficult to solve in these terms, while ternary solutions are even more difficult. Here, we present a method of data pretreatment that facilitates the use of the Parallel...
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DMSO and TMAO—Differences in Interactions in Aqueous Solutions of the K-Peptide
PublikacjaInteractions between a solvent and their co-solute molecules in solutions of peptides are crucial for their stability and structure. The K-peptide is a synthetic fragment of a larger hen egg white lysozyme protein that is believed to be able to aggregate into amyloid structures. In this study, a complex experimental and theoretical approach is applied to study systems comprising the peptide, water, and two co-solutes: trimethylamide...
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Amides as models to study the hydration of proteins and peptides — spectroscopic and theoretical approach on hydration in various temperatures
PublikacjaInteractions with water are one of the key factors which determine protein stability and activity in aqueous solutions. However, the protein hydration is still insufficiently understood. N-methylacetamide (NMA) is regarded as a minimal part of the peptide backbone and the relative simplicity of its structure makes it a good model for studies on protein–water interactions. In this paper, the influence of NMA and N,N-dimethylacetamide...
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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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The Physicochemical and Antibacterial Properties of Chitosan-Based Materials Modified with Phenolic Acids Irradiated by UVC Light
PublikacjaThis paper concerns the physicochemical properties of chitosan/phenolic acid thin films irradiated by ultraviolet radiation with wavelengths between 200 and 290 nm (UVC) light. We investigated the preparation and characterization of thin films based on chitosan (CTS) with tannic (TA), caffeic (CA) and ferulic acid (FA) addition as potential food‐packaging materials. Such materials were then exposed to the UVC light (254 nm) for...
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The effect of a miniature argon flow rate on the spectral characteristics of a direct current atmospheric pressure glow micro-discharge between an argon microjet and a small sized flowing liquid cathode
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Ultrasonic nebulization atmospheric pressure glow discharge — Preliminary study
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Formation of CN (B2∑+) radicals in the vacuum-ultraviolet photodissociation of pyridine and pyrimidine molecules
PublikacjaFormation of the excited CN(B2∑+) free radicals in the photodissociation of pyridine (C5H5N) and pyrimidine (C4H4N2) molecules was investigated over the energy ranges 16–27 and 14.7–25 eV, respectively. Photon-induced fluorescence spectroscopy was applied to detect the vibrationally and rotationally excited CN radicals by recording the B2∑+→X2∑+ emission bands (violet system). The measured dissociation yield curves demonstrate...