Search results for: fractional derivatives and integrals
-
Influence of Osmolytes on Protein and Water Structure: A Step To Understanding the Mechanism of Protein Stabilization
PublicationResults concerning the thermostability of hen egg white lysozyme in aqueous solutions with stabilizing osmolytes, trimethylamine-N-oxide (TMAO), glycine (Gly), and its N-methyl derivatives, N-methylglycine (NMG), N,N-dimethylglycine (DMG), and N,N,N-trimethylglycine (betaine, TMG), have been presented. The combination of spectroscopic (IR) and calorimetric (DSC) data allowed us to establish a link between osmolytes’ influence on...
-
Synthesis and steroid sulfatase inhibitory activities of N-alkanoyl tyramine phosphates and thiophosphates
PublicationA series of phosphate and thiophosphate analogs based on the frameworks of N-alkanoyl tyramines have been synthesized and biologically evaluated. Their binding modes have been modeled using docking techniques. The inhibitory effects of the synthesized compounds were tested on STS isolated from the human placenta as well as the MCF-7, MDA-MB-231 and SkBr3 cancer cell lines. Most of the new STS inhibitors possessed potent activity...
-
Effect of Acetylation and Beta‐Amylase Treatment on Complexation of Debranched Starch with Naringenin
PublicationStarch inclusion complexation has been shown to improve solubility of water insoluble molecules. Potato starch and Hylon VII are acetylated at two levels and then debranched alone or combined with β‐amylase hydrolysis, and its complexes with naringenin are prepared in aqueous conditions and characterized in this study. Both soluble and insoluble complexes are formed with the soluble complex present in the supernatant and the insoluble...
-
Structural changes of water caused by non-electrolytes: Volumetric and compressibility approach for urea-like analogues
PublicationHydration of thiourea (TU), hydroxyurea (HU, hydroxycarbamide), acetone (AC, 2-propanone) and dimethyl sulfoxide (DMSO) has been investigated with the help of the volumetric and compression measurement. The apparent molar volumes and the apparent molar isentropic (adiabatic) compression have been calculated from the density and speed of sound data at temperatures ranging from 288.15 to 308.15 K at atmospheric pressure (0.1 MPa)....
-
Electron-Induced Decomposition of Uracil-5-yl O-(N,N-dimethylsulfamate): Role of Methylation in Molecular Stability
PublicationThe incorporation of modified uracil derivatives into DNA leads to the formation of radical species that induce DNA damage. Molecules of this class have been suggested as radiosensitizers and are still under investigation. In this study, we present the results of dissociative electron attachment to uracil-5-yl O-(N,N-dimethylsulfamate) in the gas phase. We observed the formation of 10 fragment anions in the studied range of electron...
-
Using FreeFEM open software for modelling the vibrations of piezoelectric devices
PublicationModelling vibrations of piezoelectric transducers has been a topic discussed in the literature for many decades. The first models - so-called one-dimensional - describe the vibrations only near operating frequency and near its harmonics. Attempts to introduce two-dimensional models were related to the possibility of one transducer working at several frequencies, including both thickness vibrations and those resulting from the transducer...
-
Design, synthesis, and biological evaluation of tetrahydroquinolinones and tetrahydroquinolines with anticancer activity
PublicationColorectal cancer (CRC) is the most commonly diagnosed cancer in Europe and the United States and the second leading cause of cancer related mortality. A therapeutic strategy used for the treatment of CRC involves targeting the intracellular levels of reactive oxygen species (ROS). In this study, we synthesized a series of novel tetrahydroquinolinones and assessed their ability to inhibit CRC growth and proliferation by evoking...
-
Low-Molecular Pyrazine-Based DNA Binders: Physicochemical and Antimicrobial Properties
PublicationPyrazine and its derivatives are a large group of compounds that exhibit broad biological activity, the changes of which can be easily detected by a substituent effect or a change in the functional group. The present studies combined theoretical research with the density functional theory (DFT) approach (B3LYP/6-311+G**) and experimental (potentiometric and spectrophotometric) analysis for a thorough understanding of the structure...
-
Electron-Induced Decomposition of 5-Bromo-4-thiouracil and 5-Bromo-4-thio-2′-deoxyuridine: The Effect of the Deoxyribose Moiety on Dissociative Electron Attachment
PublicationWhen modified uridine derivatives are incorporated into DNA, radical species may form that cause DNA damage. This category of molecules has been proposed as radiosensitizers and is currently being researched. Here, we study electron attachment to 5-bromo-4-thiouracil (BrSU), a uracil derivative, and 5-bromo-4-thio-20 -deoxyuridine (BrSdU), with an attached deoxyribose moiety via the N-glycosidic (N1-C) bond. Quadrupole mass spectrometry...
-
Application of Diffusion Models in the Analysis of Financial Markets: Evidence on Exchange Traded Funds in Europe
PublicationExchange traded funds (ETFs) are financial innovations that may be considered as a part of the index financial instruments category, together with stock index derivatives. The aim of this paper is to explore the trajectories and formulates predictions regarding the spread of ETFs on the financial markets in six European countries. It demonstrates ETFs’ development trajectories with regard to stock index futures and options that...
-
Studies on the charge density distribution in p-substituted phenylnitrenium cation
PublicationAniline and its derivatives are known to be mutagenic. This activity is caused by the formation of phenylnitrenium cations during aniline oxidation. Reactivity of the positively charged chemical species can be measured by means of s+ substituent constant. In this paper charge density distribution in p-substituted nitrenium cations and reactivity indices such as, hardness η, electronegativity χ , and electrophilicily ω were analyzed....
-
Applicability of phenolic acids as effective enhancers of cocrystals solubility of methylxanthines
PublicationApplicability of phenolic acids as potential cocrystal formers for methylxanthine derivatives was analyzed both in terms of cocrystallization probabilities and solubility advantage. The cocrystal formation abilities were evaluated using mixing enthalpy estimated within the conductor like screening model for real solvents (COSMO-RS) framework. The solubility improvement of potential cocrystals was estimated by formulation of the...
-
Miniaturized passive emission test chamber for in-situ measurement of emissions of organic compounds
PublicationThe results of many different studies have demonstrated unequivocally that the quality of indoor air is often much worse than that of atmospheric air (outdoor). One of the main groups of chemical compounds present in indoor air, with proven harmfulness to health,are volatile organic compounds (VOCs). VOCs present indoor comprise a wide variety of hydrocarbons and hydrocarbons derivatives including aliphatic, aromatics, alkylbenzens,...
-
Synthesis of 5-Substituted 1H-Tetrazoles from Nitriles in the Presence of Heterogeneous Catalyst
PublicationTetrazoles are five-membered heterocyclic compounds containing in their rings four nitrogen atoms. They have wide applications as corrosion inhibitors, analytical reagents, high-energy materials and gas generating compositions. Tetrazoles also play important role in coordination chemistry as ligands and in medicinal chemistry as metabolically stable surrogates for carboxylic acids. In recent years, investigation of new method of...
-
Zero-pole approach to computer aided design of in-line siw filters with transmission zeros
PublicationThis paper presents a design of a new type of in-line pseudo-elliptic filters implemented in substrate integrated waveguide(SIW) technology. To realize transmission zeros in in-line topology,frequency-dependent couplings were used. Such dispersive couplingswere implemented as shorted stubs. The design process startswith the generation of a suitable starting point. To this end, anapproximation of SIW as a rectangular waveguide is...
-
Steroid Sulfatase Inhibitors Based on Phosphate and Thiophosphate Flavone Analogs
PublicationA series of phosphate and thiophosphate flavone derivatives were synthesized and biologically evaluated in vitro for inhibition of steroid sulfatase (STS) activity. The described synthesis includes the straightforward preparation of 7-hydroxy-2-phenyl-4H-chromen-4-one 3a, 2-(4-fluorophenyl)-7-hydroxy-4H-chromen-4-one 3b, 7-hydroxy-2-(4-(trifluoromethyl)phenyl)-4H-chromen-4-one 3c, 7-hydroxy-2-(p-tolyl)-4H-chromen-4-one 3d modified...
-
New conjugates of tuftsin and muramyl dipeptide as stimulators of human monocytes-derived dendritic cells
PublicationMuramyl dipeptide (MDP) and tuftsin are known biologically active compound displaying a significant influence on various cell populations of innate immune response. MDP, as a fragment of bacterial cell wall, stimulates not only macrophages and monocytes, but also dendritic cells. In contrast, little is known about tuftsin influence on these cells. Therefore it seemed vital to access whether tuftsin or its derivatives conjugated...
-
Phage-Directed Synthesis of Photoluminescent Zinc Oxide Nanoparticles under Benign Conditions
PublicationBiological systems, especially bacteriophages and peptides, are an attractive green alternative to other known methods of nanoparticle synthesis. In this work, for the first time, bacteriophages were employed to synthesize a specific peptide, capable of producing nanoparticles (NPs). Derivatives of M13 bacteriophage exposing a ZnO-binding peptide (TMGA-LGLKWPV) on either pIII or pVIII phage coat protein were constructed and used...
-
Biosynthetic and synthetic access to amino sugars.
PublicationAmino sugars are important constituents of a number of biomacromolecules and products of mi crobial secondary metabolism, including antibiotics. For most of them, the amino group is located at the positions C1, C2 or C3 of the hexose or pentose ring. In biological systems, amino sugars are formed due to the catalytic activity of specific aminotransferases or amidotransferases by introducing an amino functionality derived from L-glutamate...
-
Solid Phase Synthesis and Biological Activity of Tuftsin Conjugates
PublicationNew tuftsin/retro-tuftsin conjugates were designed and synthesized using a classical fluorenylmethoxycarbonyl (Fmoc) solid phase procedure. All the peptide conjugates were divided into three series: 1,4-dihydroxyanthraquinone (type A), 1-nitroacridine (type B), and 4-carboxyacridone (type C) derivatives. In type A conjugates, the N-terminal group of the peptide chain is directly connected to the anthraquinone ring at C1 (Scheme...
-
In silico assessment and sonochemical synthesis of 2-alkynyl 3-chloropyrazines as prospective ligands for SARS-CoV-2
PublicationThe recent global pandemic caused by COVID-19 has triggered an intense effort worldwide towards the development of an effective cure for this disease. In our effort we have explored the 2-alkynyl substituted 3-chloropyrazine framework as a potential template for the design of molecules for this purpose. Our strategy was supported by the in silico studies of representative compounds to assess their binding affinities via docking...
-
Development of Safirinium dyes for new applications: fluorescent staining of bacteria, human kidney cells, and the horny layer of the epidermis
PublicationLow-molecular synthetic fluorophores are convenient tools in bioimaging applications. Several derivatives of Safirinium dyes as well as their reactive N-hydroxysuccinimide (NHS) esters bearing diverse substituents were synthesized and evaluated experimentally in terms of their lipophilicity by means of reverse-phase and immobilized artificial membrane high-performance liquid chromatography. Subsequently, the selected compounds...
-
Phosphinophosphoranes: Mixed-Valent Phosphorus Compounds with Ambiphilic Properties
PublicationHerein, 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...
-
Information and communication technologies versus diffusion and substitution of financial innovations. The case of exchange-traded funds in Japan and South Korea
PublicationThe substitution between financial innovations, exchange-traded funds (ETFs), and stock index derivatives (i.e. index financial instruments) is one of the relatively understudied topics of the financial sciences. The current study aims to verify empirically the diffusion and substitution of ETFs in the market for index financial instruments. It presents in-depth analysis of the development of index financial instruments traded...
-
Testing Stability of Digital Filters Using Optimization Methods with Phase Analysis
PublicationIn this paper, novel methods for the evaluation of digital-filter stability are investigated. The methods are based on phase analysis of a complex function in the characteristic equation of a digital filter. It allows for evaluating stability when a characteristic equation is not based on a polynomial. The operation of these methods relies on sampling the unit circle on the complex plane and extracting the phase quadrant of a function...
-
Fluorescent analogs of trypsin inhibitor SFTI-1 isolated from sunflower seeds-synthesis and applications
PublicationThis article describes the synthesis and enzymatic study of newly synthesized analogs of trypsin inhibitors SFTI-1 that were fluorescent labeled on their N-terminal amino groups. Two fluorescent derivatives of benzoxazole (3-[2-(4-diphenylaminophenyl) benzoxazol-5-yl]-L-alanine[(4NPh(2)) Ph] Box-Ala and 3-[2-(2', 4', 5'-trimethoxyphenyl) benzoxazol-5-yl]-l-alanine-[2,4,5-(OMe)3Ph] Box-Ala) were used as efficient fluorescent labels....
-
Sensitive simultaneous determination of 19 fluorobenzoic acids in saline waters by solid-phase extraction and liquid chromatography–tandem mass spectrometry
PublicationA solid-phase extraction (SPE) procedure using C18 stationary phase was optimized for the preconcentration of 19 fluorinated derivatives of benzoic acid (FBA): mono-, di-, tri-, and tetrafluorosubstituted in the ring, trifluoromethylbenzoic acid and 3,5-bistrifluoromethyl benzoic acid from undiluted salt-rich (>20%) reservoir waters. Quantitative (>90%) retention/elution of 16 out of 19 analyte compounds was achieved allowing a...
-
Synthesis and characterization of ruthenium and rhenium dyes with phosphonate anchoring groups
PublicationRe(L1)–Re(L3), a series of rhenium(I) tricarbonyl chloride complexes with bpy-R2 derivatives L1–L3 (bpy = 2,2′-bipyridine, R represents the substitution at the 4- and 4′-positions), and their corresponding trishomoleptic Ru(L1)3–Ru(L3)3 as well as heteroleptic ruthenium(II) complexes Ru(tbbpy)2(L1) and Ru(tbbpy)2(L2) have been synthesized and characterized. Their applicability as immobilizable metal–organic chromophores in solar...
-
New bis(azobenzocrown)s with dodecylmethylmalonyl linkers as ionophores for sodium selective potentiometric sensors
PublicationNovel biscrowns 1 and 2 were synthesized from 13-membered azobenzocrown ethers containing bromoalkylenoxy chains in para position relative to the azo group. The synthesized diester molecules are dodecylmethylmalonic acid derivatives differing by the linker length. The synthesized compounds have the potential of being used as sodium ionophores in ion-selective electrodes. They were characterized and used as ionophores in classic...
-
The influence of pre- and postharvest treatments on selected biological and epigenetic activities of Brassica sprouts
PublicationIntroduction The Brassica vegetables are rich in glucosinolates (GLs), which are enzymatically hydrolysed to bioactive isothiocynates (ITC) and indoles, regarded as the most promising chemopreventing agents. However, in the majority of brassica sprouts the GL conversion into these beneficial derivatives occurs at the level of about 1 %, while in cabbage leaves exceeds 70%. Since sprouts represent plant material, which is frequently...
-
Synthesis, molecular structure, and metabolic stability of new series of N' -(2-alkylthio-4-chloro-5-methylbenzenesulfonyl)-1-(5-phenyl-1 H -pyrazol-1-yl)amidine as potential anti-cancer agents
PublicationA series of new N'-(2-alkylthio-4-chloro-5-methylbenzenesulfonyl)-1-(5-phenyl-1H-pyrazol-1-yl)amidine derivatives have been synthesized and evaluated in vitro by MTT assays for their antiproliferative activity against cell lines of colon cancer HCT-116, cervical cancer HeLa and breast cancer MCF-7. The studied compounds display selective activity mainly against HCT-116 and HeLa cells. Thus, five compounds show selective cytotoxic...
-
Polymerization of chloro-p-xylylenes, quantum-chemical study
PublicationThe p-xylylene monomers of parylene N, C and D have similar high polymerization reactivity. For effective copolymerization processes this fact is basically a draw- back and for instance the copolymerization with styrene doesn't go at all (Corley et al. J Pol Sc 13(68):137156, 1954). Substitution of terminal hydrogen atoms by chlorine atoms reduces reactivity dramatically. 7,7,8,8-tetrachloro-p- xylylene and 2,5,7,7,8,8-hexachloro-p-xylylene...
-
Data regarding a new, vector-enzymatic DNA fragment amplification-expression technology for the construction of artificial, concatemeric DNA, RNA and proteins, as well as biological effects of selected polypeptides obtained using this method
PublicationApplications of bioactive peptides and polypeptides are emerging in areas such as drug development and drug delivery systems. These compounds are bioactive, biocompatible and represent a wide range of chemical properties, enabling further adjustments of obtained biomaterials. However, delivering large quantities of peptide derivatives is still challenging. Several methods have been developed for the production of concatemers –...
-
Waste printer ink as modifier for natural rubber/carbon black composites: No haste, use waste
PublicationFrom a sustainability perspective, achieving a greener future with a minimal carbon footprint requires maximizing waste materials' reuse. The four pillars of satisfying customer demands are processing, price, properties, and performance. Along with such a global policy, this work seeks to utilize waste printer ink (WPI) as a source of carbon in combination with low- and high-surface carbon black (LCB and HCB, respectively) additives...
-
Towards large-scale application of nanoporous materials in membranes for separation of energy-relevant gas mixtures
PublicationMembranes containing nanoporous materials (such as zeolites, metal–organic materials and 2D materials such as graphene derivatives) may allow more efficient separation of gas mixtures relevant to emerging energy technologies. For example, such membranes could be applied in the separation of gases containing mixtures of carbon dioxide (CO2) and hydrogen (H2). However, these membranes are currently at a relatively low technology...
-
On implementation of fibrous connective tissues’ damage in Abaqus software
PublicationConnective fibrous tissues, such as tendons and ligaments, in humans and animals exhibit hyperelastic behaviour. The constitution of the material of these tissues is anisotropic due to the presence of the collagen fibres, where one family of fibres is the typical case. Traumatic events and/or aging may sometimes lead to the damage of the tissue. The study of motion of affected joints or limbs is usually not permitted in vivo. This...
-
Joint experimental and theoretical study on low-energy elastic electron scattering by gaseous alkynes: Differential cross sections, shape resonances, and methylation effects
PublicationA detailed comparison of experimental and theoretical elastic cross sections for low-energy electron scattering by ethyne, taken earlier in our group by Gauf et al. [Phys. Rev. A 87, 012710 (2013)], and some of its methylated derivatives, propyne, and the isomers 1-butyne and 2-butyne, taken here, are presented. The present differential cross sections were measured at incident electron energies ranging from 1 eV to 30 eV and...
-
Chiral Schiff base complexes as an effective catalyst in Diels-Alder reaction
PublicationDiels Alder reaction is a very important tool in carbon-carbon bond formation. It is a cycloaddition between a conjugated diene and a second compound called dienophile. Where one or more heteroatoms are present in the diene and/or dienophile framework, the cycloaddition is called hetero-Diels-Alder reaction (HDA). The asymmetric Diels-Alder reaction is among the most powerful available methodologies for that construction of optically...
-
Modern approach for determination of lactulose, mannitol and sucrose in human urine using HPLC-MS/MS for the studies of intestinal and upper digestive tract permeability
PublicationA new analytical procedure was described for the simultaneous determination of lactulose, mannitol and sucrose in urine, in which HILIC chromatography and tandem mass spectrometry detection are used. Sugars are orally administered for the estimation of intestinal permeability in children digestive tract. Samples were purified by dispersive solid phase extraction (d-SPE) using Amberlite MB150 resin. Raffinose was selected as an...
-
Electron scattering cross sections for 1-pentene, H2C=CH-(CH2)2CH3, molecules
PublicationCross sections, both experimental and theoretical, are reported for electron scattering from 1-pentene (C5H10) molecules. Absolute grand-total cross sections (TCSs) were measured at electron impact energies ranging from 1 to 300 eV, using a linear electron-transmission technique. The dominant behaviour of the experimental TCS energy function is a distinct asymmetric enhancement with the maximum located around 6.5 eV. Discernible...
-
Application of dispersive liquid-liquid microextraction and gas chromatography with mass spectrometry for the determination of oxygenated volatile organic compounds in effluents from the production of petroleum bitumen
PublicationWepresent a new procedure for the determination of oxygenated volatile organic compounds in samples of postoxidative effluents from the production of petroleum bitumens using dispersive liquid–liquid microextraction and gas chromatography with mass spectrometry. The eight extraction parameters were optimized for 43 oxygenated volatile organic compounds. The detection limits obtained ranged from 0.07 to 0.82 g/mL for most of the...
-
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...
-
Assessment of hearing in coma patients employing auditory brainstem response, electroencephalography, and eye-gaze-tracking
PublicationThe results of the study conducted by Tagliaferri et al. in 12 European countries indicate that the ratio of registered brain injury cases in Europe amounts to 150-300 per 100 000 people, with the European mean value of 235 cases per 100 000 people. The project presented in the paper assumes development of a combined metric of patients’ state remaining in coma by intelligent fusion of GCS (subjective Glasgow Coma Scale or its derivatives)...
-
Structural and dynamic insights on the EmrE protein with TPP+ and related substrates through molecular dynamics simulations
PublicationEmrE is a bacterial transporter protein that forms an anti-parallel homodimer with four transmembrane helices in each monomer. EmrE transports positively charged aromatic compounds, such as TPP+ and its derivatives. We performed molecular dynamics (MD) simulations of EmrE in complex with TPP+, MeTPP+, and MBTPP+ embedded in a membrane. The detailed molecular properties and interactions were analysed for all EmrE-ligand complexes....
-
Cross sections for electron collision with pyridine [C5H5N] molecule
PublicationThe absolute grand -total cross section (TCS) for electron scattering from pyridine, C5H5N, molecules has been measured at impact energies from 0.6 to 300 eV in the linear electron-transmission experiment. The obtained TCS energy dependence appears to be typical for targets of high electric-dipole moment; the cross section generally decreases with rising energy, except for the 3–20 eV range, where a broad enhancement peaked near...
-
Recent advances in rapid multiobjective optimization of expensive simulation models in microwave and antenna engineering by Pareto front exploration
PublicationPractical engineering design problems are inherently multiobjective, that is, require simultaneous control of several (and often conflicting) criteria. In many situations, genuine multiobjective optimization is required to acquire comprehensive information about the system of interest. The most popular solution techniques are populationbased metaheuristics, however, they are not practical for handling expensive electromagnetic...
-
Synthesis and Biological Evaluation of Acridine/Acridone Analogs as Potential Anticancer Agents
PublicationAcridine and acridone analogues were prepared by Ullmann condensation and then cyclization reaction. As a result of nucleophilic substitution reaction 1-nitro-9-phenoxyacridine or 1-chloro-4-nitro-9(10H)-acridone with the corresponding peptides, the planned acridine derivatives (10a-c, 12, 17-a-d, 19) have been obtained. The cytotoxic activity of the newly obtained analogs were evaluated against melanotic (Ma) and amelanotic (Ab)...
-
Influence of Storage Time and Temperature on the Toxicity, Endocrine Potential, and Migration of Epoxy Resin Precursors in Extracts of Food Packaging Materials
PublicationThe aim of the present study was to establish a standard methodology for the extraction of epoxy resin precursors from several types of food packages (cans, multi-layered composite material, and cups) with selected simulation media (distilled water, 5% ethanol, 3% dimethyl sulfoxide, 5% acetic acid, artificial saliva) at different extraction times and temperatures (factors). Biological analyses were conducted to determine the acute...
-
Expedited Design Closure of Antenna Input Characteristics by Trust Region Gradient Search and Principal Component Analysis
PublicationOptimization-based parameter tuning has become an inherent part of contemporary antenna design process. For the sake of reliability, it is typically conducted at the level of full-wave electromagnetic (EM) simulation models. This may incur considerable computational expenses depending on the cost of an individual EM analysis, the number of adjustable variables, the type of task (local, global, single-/multi-objective optimization),...
-
Computationally-efficient design optimisation of antennas by accelerated gradient search with sensitivity and design change monitoring
PublicationElectromagnetic (EM) simulation tools are of primary importance in the design of contemporary antennas. The necessity of accurate performance evaluation of complex structures is a reason why the final tuning of antenna dimensions, aimed at improvement of electrical and field characteristics, needs to be based on EM analysis. Design automation is highly desirable and can be achieved by coupling EM solvers with numerical optimisation...