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Search results for: ACRIDINONE DERIVATIVES
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Molecular dynamics simulations of the affinity of chitin and chitosan for collagen: the effect of pH and the presence of sodium and calcium cations
PublicationChitosan and chitin are promising biopolymers used in many areas including biomedical applications, such as tissue engineering and viscosupplementation. Chitosan shares similar properties with hyaluronan, a natural component of synovial fluid, making it a good candidate for joint disease treatment. The structural and energetic consequences of intermolecular interactions are crucial for understanding the biolubrication phenomenon...
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CHARACTERISATION OF CHITOSAN/HYALURONIC ACID BLEND FILMS MODIFIED BY COLLAGEN
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INFLUENCE OF THE INTERMOLECULAR INTERACTION ON PHYSICO-CHEMICAL PROPERTIES OF CHITOSAN/HYALURONIC ACID BLENDS
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THE INFLUENCE OF THE TYPE SOLVENT ON THE STRUCTURE OF CHITOSAN BLENDS WITH HYALURONIC ACID
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EFFECT OF CHITOSAN AND LIPID LAYERS DEPOSITED ONTO POLYETHYLENE TEREPHTHALATE (PET) ON ITS WETTING PROPERTIES
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WETTABILITY OF HYBRID CHITOSAN/PHOSPHOLIPID COATINGS
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WETTABILITY OF CHITOSAN-MODIFIED AND LIPID/POLYPEPTIDE-COATED PEEK SURFACES
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SURFACE CHARACTERISTICS OF DPPC MONOLAYERS DEPOSITED FROM TITANIUM DIOXIDE–CHITOSAN–HYALURONIC ACID SUBPHASES ON A GLASS SUPPORT
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CHARACTERIZATION OF MIXED LANGMUIR MONOLAYERS OF CYCLOSPORINE A WITH THE PHOSPHOLIPID DPPC AT THE CHITOSAN SUBPHASE
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BEHAVIOUR OF TiO2/CHITOSAN DISPERSION AS A FUNCTION OF SOLUTION pH
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REVIEW OF CURRENT RESEARCH ON CHITOSAN AS A RAW MATERIAL IN THREE-DIMENSIONAL PRINTING TECHNOLOGY IN BIOMEDICAL APPLICATIONS
PublicationThree-dimensional (3D) biomaterial manufacturing strategies show an extraordinary driving force for the development of innovative solutions in the biomedical sector, including drug delivery systems, disease modelling and tissue and organ engineering. Due to its remarkable and promising biological and structural properties, chitosan has been widely studied for decades in several potential applications in the biomedical field. However,...
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FDTD Method for Electromagnetic Simulations in Media Described by Time-Fractional Constitutive Relations
PublicationIn this paper, the finite-difference time-domain (FDTD) method is derived for electromagnetic simulations in media described by the time-fractional (TF) constitutive relations. TF Maxwell’s equations are derived based on these constitutive relations and the Grünwald–Letnikov definition of a fractional derivative. Then the FDTD algorithm, which includes memory effects and energy dissipation of the considered media, is introduced....
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First Copper(I) and Silver(I) Complexes Containing Phosphanylphosphido Ligands
PublicationThree new complexes with phosphanylphosphido ligands, [Cu4{μ2-P(SiMe3)-PtBu}4](1), [Ag4{μ2-P(SiMe3)-PtBu2}4](2) and [Cu{η1-P(SiMe3)-PiPr2}2]–[Li(Diglyme)2] (3) were synthesized and structurally characterized by X-ray diffraction, NMR spectroscopy, and elemental analysis. Complexes 1 and 2 were obtained in the reactionsof lithium derivative of diphosphane tBu2P-P(SiMe3)Li·2.7THF withCuCl and [iBu3PAgCl]4, respectively....
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Novel and Efficient Synthesis of Unsymmetrical Trisulfides
PublicationWe have developed a convenient method for the synthesis of unsymmetrical trisulfides under mild conditions in very good yields. The designed method is based on the straightforward preparation of 1-[(5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)trisulfanyl]dodecane from readily available 5,5-dimethyl-2-sulfanyl-2-thioxo-1,3,2-dioxaphosphorinane, sulfur dichloride (SCl2) and dodecane-1-thiol. The unsymmetrical trisulfides can...
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An efficient and convenient synthesis of unsymmetrical disulfides from thioacetates
PublicationWe have developed convenient methods for the synthesis of functionalized unsymmetrical dialkyl disulfides under mild conditions in very good yields. The designed method is based on the reaction of (5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl)-disulfanyl derivatives 1 with functionalized alkyl thiolate anions, generated in situ from thioacetates2and sodium methoxide or butylamine. The developed method allows the preparation...
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Inhibition of impurities formation in the synthesis of N-alkyltheobromines stimulated by microwave irradiation. Cationic and anionic response of membrane electrodes
PublicationN-Alkyltheobromine (1-9) derivatives were obtained by reacting theobromine with appropriate alkyl halide under microwave irradiation at 100-150 W and by conventional synthesis. Formation of by-products of oxygen atom alkylation and 1-N-alkyltheobromine ring opening were considered. The presented compounds 1-5 have been studied as ion carriers in ion-selective membrane electrodes. Selectivity of these membranes was studied towards...
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Phosphate tricyclic coumarin analogs as steroid sulfatase inhibitors: synthesis and biological activity.
PublicationIn the present work, we report convenient methods for the synthesis and biological evaluation of phosphate tricyclic coumarin derivatives as potential steroid sulfatase inhibitors. The described synthesis includes the straightforward preparation of 7-hydroxy-2,3-dihydro-1H-cyclopenta[c]chromen-4-one, 3-hydroxy-7,8,9,10-tetrahydro-6H-benzo[c]chromen-6-one and 3-hydroxy-8,9,10,11-tetrahydro-7H-cyclohepta[c]chromen-6-one modified...
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Decomposition of halogenated nucleobases by surface plasmon resonance excitation of gold nanoparticles
PublicationHalogenated uracil derivatives are of great interest in modern cancer therapy, either as chemotherapeutics or radiosensitisers depending on their halogen atom. This work applies UV-Vis spectroscopy to study the radiation damage of uracil, 5-bromouracil and 5- uorouracil dissolved in water in the presence of gold nanoparticles upon irradiation with an Nd:YAG ns-pulsed laser operating at 532nm at dierent uences. Gold nanoparticles...
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Morphology, Mechanical and Thermal Properties of Thermoplastic Polyurethane Containing Reduced Graphene Oxide and Graphene Nanoplatelets
PublicationPolyurethane/graphene nanocomposites were synthesized using commercial thermoplastic polyurethane (TPU, Apilon 52DE55), and two types of graphene derivatives: graphene nanoplatelets (GNP) and reduced graphene oxide (RGO). Fourier Transformation Infrared Spectroscopy Fourier Transformation Infrared Spectroscopy (FTIR) spectroscopy, TEM, and SEM microscopy and XRD techniques were used to chemically and structurally characterize GNP...
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Cytotoxic and Antioxidant Activities of Benzohydroxamic Acid Analogues
Publication20 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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Acceleration waves in the nonlinear micromorphic continuum
PublicationWithin the framework of the nonlinear elastic theory of micromorphic continua we derive the conditions for propagation of acceleration waves. An acceleration wave, also called a wave of weak discontinuity of order two, can be treated as a propagating nonmaterial surface across which the second derivatives of the placement vector and micro-distortion tensor may undergo jump discontinuities. Here we obtain the acoustic tensor for...
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Tuftsin-Properties and Analogs
PublicationImmunomodulation is one of the significant therapeutic strategies. It includes both stimulation or suppression of the immune system by a variety of substances called immunomodulators, designed to regulate the immune response of the organism to infections of varying etiology. An example of such a substance is tuftsin (TKPA) 3 (Fig. (1)). Tuftsin is an endogenous immunomodulator of a wide spectrum of biological activity. Tetrapeptide...
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BODIPY‐Perylene Charge Transfer Compounds; Sensitizers for Triplet‐Triplet Annihilation Up‐conversion
PublicationBODIPY heterochromophores, asymmetrically substituted with perylene and/or iodine at the 2 and 6 positions were prepared and investigated as sensitizers for triplet-triplet annihilation up conversion (TTA-UC). Single-crystal X-ray crystallographic analyses show that the torsion angle between BODIPY and perylene units lie between 73.54 and 74.51, though they are not orthogonal. Both compounds show intense, charge transfer absorption...
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Stochastic intervals for the family of quadratic maps
Open Research DataNumerical analysis of chaotic dynamics is a challenging task. The one-parameter families of logistic maps and closely related quadratic maps f_a(x)=a-x^2 are well-known examples of such dynamical systems. Determining parameter values that yield stochastic-like dynamics is especially difficult, because although this set has positive Lebesgue measure,...
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Synthesis and structure determination of 2,3-diaryl-9,9-dioxo-1H-9-thia-1,4,4a,7,10-pentaazaphenanthrene-2-ols
Publication3-Amino-1,1-dioxopyrido[4,3-e]-1,4,2-dithiazine has been synthesized and applied to the synthesis of 3-amino-2-(4-thioxo-1,4-dihydropyridin-3-ylsulfonyl)guanidine. The reaction of the aminoguanidine with the appropriate 1,2-diarylethane-1,2-diones afforded 2,3-diaryl-9,9-dioxo-1H-9-thia-1,4,4a,7,10-pentaazaphenanthrene-2-ol derivatives. The structure of these compounds, which represent a novel heterocyclic ring system, was confirmed...
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A versatile and convenient preparation of unsymmetrical diaryl disulfides
PublicationWe have developed a convenient method for the synthesis of unsymmetrical diaryl disulfides under mild conditions in excellent yields. The described method is based on the straightforward preparation of 5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinane-2-sulfenyl bromide from readily available 5,5-dimethyl-2-thiolo-2-thioxo-1,3,2-dioxaphosphorinane or bis(5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl) disulfide. The unsymmetrical...
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Convenient Synthesis of Functionalized Unsymmetrical Vinyl Disulfides and Their Inverse Electron-Demand Hetero-Diels-Alder Reaction
PublicationThe simple, convenient, and efficient methods for the preparation of unsymmetrical vinyl disulfides with additional functional groups under mild conditions with moderate to high yields were designed. The developed methods include the reaction of S-vinyl phosphorodithioate with thiotosylates or S-vinyl thiotosylate with thiols. The designed methods allow for the synthesis of unsymmetrical vinyl disulfides with additional functionalities...
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Analysis of Crash Computation on a Basis of the Pronciple of Linear Momentum and Kinetic Energy
PublicationThe article shows the calculation of a vehicle crash with a fixed pile, modelled by the finite element method. There were compared during the crash simulations changes in kinetic energy, as well as – changes in linear momentum and its derivative, with respect to time. Calculations were made in the HyperWorks CAE software environment. The obtained results show influence of various body parts and devices of the deceleration on...
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The synthesis and structure of a potential immunosuppressant: N-mycophenoyl malonic acid dimethyl ester
PublicationThe synthesis of a potential immunosuppressant, i.e. dimethyl ester of N-mycophenoyl malonic acid was optimized in the reaction of mycophenolic acid (MPA) with amino malonic dimethyl ester in the presence of propanephosphonic anhydride (T3P) as a coupling reagent. The structural properties of the obtained MPA derivative were investigated by NMR, MS and single crystal X-ray diffraction methods. Theoretical considerations of conformational...
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The II phase metabolism of endogenous and exogenous compounds, including antitumor chemotherapeutics
PublicationThe II phase metabolism, it is a set of metabolism and excretion pathways of endogenous as well as exogenous compounds including xenobiotics. UDP-glucuronyltransferases (UGTs; EC 2.4.1.17) are the most crucial representatives of II phase enzymes, which are responsible for the transformation of bilirubine and bile acids, steroids and thyroid hormones and lipids. Exogenous compounds, including drugs, carcinogens, environmental pollutants...
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Positive solutions to fractional differential equations involving Stieltjes integral conditions
PublicationIn this paper, we investigate nonlocal boundary value problems for fractional differential equations with dependence on the first-order derivatives and deviating arguments. Sufficient conditions which guarantee the existence of at least three positive solutions are new and obtained by using the Avery–Peterson theorem. We discuss problems (1) and (2) when argument b can change the character on [0, 1], so in some subinterval I of...
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Investigation of polyurethane elastomer–steel joints using glass lacquer as an adhesive agent
PublicationThis article describes an innovative method of coupling polyurethane elastomer (based on polyurethane glycolysate) with constructional steel, by implementation of a Glaspur®—glass lacquer containing latent polyurethanes and monosilane adhesion promoters. The commonly applied coupling agent is Cilbond® 45SF glue or its derivatives. Additionally, glycolysate was synthesised from polyurethane waste and 1,3-propylene glycol in 6:1...
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Absorbing Boundary Conditions Derived Based on Pauli Matrices Algebra
PublicationIn this letter, we demonstrate that a set of absorbing boundary conditions (ABCs) for numerical simulations of waves, proposed originally by Engquist and Majda and later generalized by Trefethen and Halpern, can alternatively be derived with the use of Pauli matrices algebra. Hence a novel approach to the derivation of one-way wave equations in electromagnetics is proposed. That is, the classical wave equation can be factorized...
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Azo group(s) in selected macrocyclic compounds
PublicationAzobenzene derivatives due to their photo- and electroactive properties are an important group of compounds finding applications in diverse fields. Due to the possibility of controlling the trans–cis isomerization, azo-bearing structures are ideal building blocks for development of e.g. nanomaterials, smart polymers, molecular containers, photoswitches, and sensors. Important role play also macrocyclic compounds well known for...
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New Simple and Robust Method for Determination of Polarity of Deep Eutectic Solvents (DESs) by Means of Contact Angle Measurement
PublicationThe paper presents a new method for evaluating the polarity and hydrophobicity of deep eutectic solvents (DESs) based on the measurement of the DES contact angle on glass. DESs consisting of benzoic acid derivatives and quaternary ammonium chlorides–tetrabutylammonium chloride (TBAC) and benzyldimethylhexadecylammonium chloride (16-BAC)—in selected molar ratios were chosen for the study. To investigate the DESs polarity, an optical...
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Weak Solutions within the Gradient-Incomplete Strain-Gradient Elasticity
PublicationIn this paper we consider existence and uniqueness of the three-dimensional static boundary-value problems in the framework of so-called gradient-incomplete strain-gradient elasticity. We call the strain-gradient elasticity model gradient-incomplete such model where the considered strain energy density depends on displacements and only on some specific partial derivatives of displacements of first- and second-order. Such models...
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Seasonal changes in organotin compounds in water and sediment samples from the semi-closed Port of Gdynia
PublicationThe effect of seasonal changes on the distribution of organotin compounds (OTC) in the sediments and seawaterfrom the docks of the Port of Gdynia was investigated. Sediment and seawater samples were collectedfrom four industrial docks in February (winter) and June (summer) in 2009. The samples were analyzed forbutyltin, phenyltin, octyltin, and tricyclohexyltin (total of 9 OTC derivatives). The fine fraction (b0.063 mm)accumulated...
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The New Test Procedure for Group-Type Composition of Base Oils of Lubricating Oils, Especially Emitted into the Environment
PublicationMineral base oil, a product of multistep fine refining of the relevant fractions from vacuum distillation of crude oil, is a main component of so-called mineral lubricating oils containing aliphatic and alicyclic substituted aromatic hydrocarbons, i.e., derivatives of benzene and biphenyl. Mineral lubricating oil is composed mostly of mineral base oil and a low amount of enriching additives, most often products of advanced organic...
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Analiza oddziaływań w kryształach związków zawierających w strukturze pierścień pirydynowy
PublicationMożliwość tworzenia się wiązań wodorowych jest kluczowym parametrem z punktu widzenia inżynierii kryształu, ponieważ wiązania wodorowe mają bezpośredni wpływ na strukturę oraz trwałość sieci krystalicznej. Głównym celem niniejszej rozprawy doktorskiej była analiza porównawcza wiązań wodorowych występujących w układach, zawierających w strukturze pierścień pirydynowy. Badane układy podzielono na: (1) układy ze związkami krzemosiarkowymi...
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9-Cyano-10-methylacridinium hydrogen dinitrate
PublicationThe title compound, C15H11N2+·HN2O6−, crystallizes in the monoclinic space group C2/c with four molecules in the unit cell. The planar 9-cyano-10-methylacridinium cations lie on crystallographic twofold axes and are arranged in layers, almost perpendicular to the ac plane, in such a way that neighbouring molecules are positioned in a `head-to-tail' manner. These cations and the hydrogen dinitrate anions are linked through C—H⋯O...
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Hydration of N-Hydroxyurea from Ab Initio Molecular Dynamics Simulations
PublicationN-Hydroxyurea (HU) is an important chemotherapeutic agent used as a first-line treatment in conditions such as sickle cell disease and β-thalassemia, among others. To date, its properties as a hydrated molecule in the blood plasma or cytoplasm are dramatically understudied, although they may be crucial to the binding of HU to the radical catalytic site of ribonucleotide reductase, its molecular target. The purpose of this work...
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Phosphate and Thiophosphate Biphenyl Analogs as Steroid Sulfatase Inhibitors
PublicationIn the present work, we report convenient methods for the synthesis and biological evaluation of phosphate and thiophosphate biphenyl derivatives exhibiting steroid sulfatase (STS) activity. The described synthesis is based on straightforward preparation of biphenyl-4-ol and 40-hydroxybiphenyl- 4-carboxylic acid ethyl ester modified with various phosphate or thiophosphate moieties. The inhibitory effects of these compounds were...
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Continuum models for pantographic blocks with second gradient energies which are incomplete
PublicationWe postulate a deformation energy for describing the mechanical behavior of so called pantographic blocks, that is bodies constituted by stacking of layers of pantographic sheets. We remark that the pantographic effect is limited in the plane of pantographic sheets and therefore only the second derivatives of transverse displacements along the pantographic fibers appear in the chosen deformation energy. We use this novel energy...
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On Anti-Plane Surface Waves Considering Highly Anisotropic Surface Elasticity Constitutive Relations
PublicationWithin the framework of highly anisotropic surface elasticity model we discuss the propagation of new type of surface waves that are anti-plane surface waves. By the highly anisotropic surface elasticity model we mean the model with a surface strain energy density which depends on incomplete set of second derivatives of displacements. From the physical point of view this model corresponds to a coating made of a family of parallel...
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Pre-treatment of bio fraction waste prior to fermentation processes
PublicationCurrent efforts are taken to increase resource efficiency, close material loops, and improve sustainable waste and by-products management. Thus, networking agro-food by-products and converting them into valuable products completely exhausting the potential of the raw material becomes significant. Model lignocellulosic and starch based biomass were subjected to pre-treatment with the application of acidic compounds, i.e. sulphuric...
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Fractional Order Circuit Elements Derived from Electromagnetism
PublicationIn this paper, derivations of fractional-order (FO) circuit-element equations from electromagnetism are presented. Whilst many papers are devoted to FO modelling of electrical circuits, there are no strong foundations for such an approach. Therefore, we investigate relations between the FO electromagnetism and the FO circuit theory. Our derivations start from quasi-static (QS) approximations of Maxwell's equations in media with...
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Approximative sequences and almost homoclinic solutions for a class of second order perturbed Hamiltonian systems
PublicationIn this work we will consider a class of second order perturbed Hamiltonian systems with a superquadratic growth condition on a time periodic potential and a small aperiodic forcing term. To get an almost homoclinic solution we approximate the original system by time periodic ones with larger and larger time periods. These approximative systems admit periodic solutions, and an almost homoclinic solution for the original system...
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Calix[4]arene-Thioamides as Ionophores for Transition and Heavy Metal cations
PublicationCalix[4]arene derivatives play an important role as sensing materials in Ion Selective Electrodes(ISEs). Nowadays a high impact is put to control in natural waters the level of toxic heavy metals, like Pb ,Cd, Hg or Cu which may cause the great risk to human health. Our goal was to design and to synthesize ligands possessing ability to bind transition and heavy metal cations. The synthesis, crystal structures,extractive and ionophoric...
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Saccharides
PublicationSaccharides are widely distributed in nature as the major component of fruits and vegetables (primarily monosaccharides), milk and malt (mainly disaccharides), and grains (mostly polysaccharides). They are an important source of energy, structural material, as well as flavor and taste factors. Molecules of this class of compounds contain mainly carbon, hydrogen, and oxygen atoms; however, most natural saccha- rides do not have...
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Iso-Partricin, an Aromatic Analogue of Amphotericin B: How Shining Light on Old Drugs Might Help Create New Ones
PublicationPartricin is a heptaene macrolide antibiotic complex that exhibits exceptional antifungal activity, yet poor selective toxicity, in the pathogen/host system. It consists of two compounds, namely partricin A and B, and both of these molecules incorporate two cis-type bonds within their heptaenic chromophores: 28Z and 30Z. In this contribution, we have proven that partricins are susceptible to a chromophore-straightening photoisomerization...