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Wyniki wyszukiwania dla: ORGANOMETALLIC CHEMISTRY
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Characterization of herbal teas containing lime flowers – Tiliae flos by HPTLC method with chemometric analysis
PublikacjaLinden trees are a source of food products called lime flowers (Tiliae flos), traditionally used in the form of infusion for the treatment of feverish colds and coughs. Lime flowers should include flowers of Tilia cordata Mill, T.x europaea L., and T. platyphyllos Scop. or a mixture of these. The aim of current research was to establish a fast, sensitive HPTLC (high-performance thin-layer chromatography) method that would allow...
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Crystal Growth, Structure, and Magnetism of the 2D Spin 1/2 Triangular Lattice Material Rb3Yb(PO4)2
PublikacjaThe single-crystal growth, crystal structure, heat capacity, and anisotropic magnetization characterization of Rb3Yb- (PO4)2, a Yb-based triangular lattice material, are presented. Single-crystal X-ray diffraction shows that Rb3Yb(PO4)2 exhibits [Yb(PO4)]∞ layers, with the Yb in an ordered plane of equilateral triangles. One phosphate group oxygen that is not a near neighbor of the magnetic Yb displays positional disorder. The...
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Hydration of Oxometallate Ions in Aqueous Solution
PublikacjaThe strength of hydrogen bonding to and structure of hydrated oxometallate ions in aqueous solution have been studied by double difference infrared (DDIR) spectroscopy and large-angle X-ray scattering (LAXS), respectively. Anions are hydrated by accepting hydrogen bonds from the hydrating water molecules. The oxygen atom of the permanganate and perrhenate ions form weaker and longer hydrogen bonds to water than the hydrogen bonds...
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The Substantial Improvement of Amphotericin B Selective Toxicity Upon Modification of Mycosamine with Bulky Substituents
PublikacjaAbstract: Background: It is assumed that the unfavorable selective toxicity of an antifungal drug Amphotericin B (AmB) can be improved upon chemical modification of the antibiotic molecule. Objective: The aim of this study was verification of the hypothesis that introduction of bulky substituents at the amino sugar moiety of the antibiotic may result in diminishment of mammalian vitro toxicity of thus prepared AmB derivatives. Methods:...
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Superconductivity in Metal-Rich Chalcogenide Ta2Se
PublikacjaThe metal–metal bond in metal-rich chalcogenide is known to exhibit various structures and interesting physical properties. Ta2Se can be obtained by both arc-melting and solid-state pellet methods. Ta2Se crystallizes a layered tetragonal structure with space group P4/nmm (No. 129; Pearson symbol tP6). Each unit cell consists of four layers of body-centered close-packing Ta atoms sandwiched between two square nets of Se atoms, forming...
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Nano Tin/Tin Oxide Attached onto Graphene Oxide Skeleton as a Fluorine Free Anode Material for Lithium-Ion Batteries
PublikacjaHerein, we show a composite formation method of tin/tin oxide nanoparticles with graphene oxide and CMC based on laser ablation technique as an electrode material for energy storage devices. The material exhibited a three-dimensional conducting graphene oxide network decorated with tin or tin oxide nanoparticles. The structure, homogeneous distribution of nanoparticles, and direct contact between inorganic and organic parts were...
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The Reactivity of Phosphanylphosphinidene Complexes of Transition Metals Toward Terminal Dihaloalkanes
PublikacjaThe reactivities of phosphanylphosphinidene complexes [(DippN)2W(Cl)(η2-P−PtBu2)]− (1), [(pTol3P)2Pt(η2- P=PtBu2)] (2), and [(dppe)Pt(η2-P=PtBu2)] (3) toward dihaloalkanes and methyl iodide were investigated. The reactions of the anionic tungsten complex (1) with stochiometric Br(CH2)nBr (n = 3, 4, 6) led to the formation of neutral complexes with a tBu2PP(CH2)3Br ligand or neutral dinuclear complexes with unusual tetradentate...
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Activation of N2O and SO2 by the P–B Bond System. Reversible Binding of SO2 by the P–O–B Geminal Frustrated Lewis Pair
PublikacjaHerein, we present the first transformation of borylphosphine into borylphosphinite using nitrous oxide. Borylphosphine reacts with N2O via insertion of a single oxygen atom into the P−B bond and formation of a P−O−B bond system. Borylphosphine and borylphosphinite capture SO2 and activate it in an irreversible and reversible manner, respectively.
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RuAl6—An Endohedral Aluminide Superconductor
PublikacjaSuperconductivity is reported in an endohedral aluminide compound, RuAl6, with Tc = 1.21 K. The normalized heat capacity jump at Tc, ΔC/γTc = 1.58, confirms bulk superconductivity. The Ginzburg–Landau parameter of κ = 9.5 shows that RuAl6 is a type-II superconductor. Electronic structure calculations for RuAl6 are explored in comparison to its structural analogue ReAl6 (Tc = 0.74 K). The stability of the phases is discussed in...
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Superconductivity on a Bi Square Net in LiBi
PublikacjaWe present the crystallographic analysis, superconducting characterization and theoretical modeling of LiBi, that contains the lightest and the heaviest nonradioactive metal. The compound crystallizes in a tetragonal (CuAu-type) crystal structure with Bi square nets separated by Li planes (parameters a = 3.3636(1)Å and c = 4.2459(2) Å, c/a = 1.26). Superconducting state was studied in detail by magnetic susceptibility and heat...
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Solvent Impact on the Diversity of Products in the Reaction of Lithium Diphenylphosphide and a Ti(III) Complex Supported by a tBu2P–P(SiMe3) Ligand
PublikacjaWe present two important trends in the reactivity ofthe titanium complex [MeNacNacTi(Cl){η2-P(SiMe3)-PtBu2}](MeNacNac− = [Ar]NC(Me)CHC(Me)N[Ar]; Ar = 2,6-iPr2Ph)with nucleophilic reagents RLi (R = Ph2P,tBuO, (Me3Si)2N, andtBu2N) depending on the reaction medium. Reaction in nonpolarsolvent (toluene) leads to three main products: via an autoredoxprocess and nucleophilic substitution at the Ti-atom to afford theTi(IV) complex [MeNacNacTi(R){η2-P-PtBu2}]...
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Superconducting SrSnP with Strong Sn–P Antibonding Interaction: Is the Sn Atom Single or Mixed Valent?
PublikacjaThe large single crystals of SrSnP were prepared using Sn self-flux method. The superconductivity in the tetragonal SrSnP is observed with the critical temperature of ∼2.3 K. The results of a crystallographic analysis, superconducting characterization, and theoretical assessment of tetragonal SrSnP are presented. The SrSnP crystallizes in the CaGaN structure type with space group P4/nmm (S.G. 129, Pearson symbol tP6) according...
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Antimicrobial Activity of Chimera Peptides Composed of Human Neutrophil Peptide 1 (HNP-1) Truncated Analogues and Bovine Lactoferrampin
PublikacjaThree chimera peptides composed of bovine lactoferrampin and the analogue of truncated human neutrophil peptide 1 were synthesized by the solid-phase method. In two compounds peptide chains were connected via isopeptide bond, whereas in the third one disulfide bridge served as a linker. All three chimeras displayed significantly higher antimicrobial activity than the constituent peptides as well as their equimolar mixtures. The...
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Dietary antioxidants as a source of hydrogen peroxide
PublikacjaStudies of 54 antioxidants revealed that 27 of them, mainly polyphenols, generated hydrogen peroxide (H2O2) when added to Dulbecco’s modified Eagle’s medium (DMEM), other media used for culture of mammalian and yeast cells and phosphate-buffered saline. The most active antioxidants were: propyl gallate (PG), (−)-epigallocatechin gallate (EGCG) and quercetin (Q). Chelex treatment and iron chelators decreased H2O2 generation suggesting...
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Design, Synthesis, and Enzymatic Evaluation of Novel ZnO Quantum Dot-Based Assay for Detection of Proteinase 3 Activity
PublikacjaHerein, the synthesis and application of functionalized quantum dot-based protease probes is described. Such probes are composed of nontoxic ZnO nanocrystals decorated by amino groups followed by linker and labeled peptide attachment. Spherical NH2-terminated ZnO quantum dots (QDs) with the average size ranging from 4 to 8 nm and strong emission centered at 530 nm were prepared using the sol−gel method. The fluorescence of ZnO...
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Synthesis and Biological Evaluation of Acridine/Acridone Analogs as Potential Anticancer Agents
PublikacjaAcridine 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)...
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MRM–MS of marker peptides and their abundance as a tool for authentication of meat species and meat cuts in single-cut meat products
PublikacjaThe abundance of protein markers in different types of meat cuts was explored in the context of authentication of raw meat (pork, beef and chicken) and processed meat products. Peptides originating from myoglobin (Mb) and myosin (My) were analyzed using multiple reaction monitoring mass spectrometry (MRM–MS). Analytical protocol was optimized for good repeatability (CV < 10%) and high sensitivity. The MS signal intensity of Mb...
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Importance of Specific Heat Characterization when Reporting New Superconductors: An Example of Superconductivity in LiGa2Rh
PublikacjaWe show that the full-Heusler compound LiGa2Rh is a superconductor with Tc = 2.4 K. The new superconductor was found as a result of an intuition-based extension of a database search for superconductors that looked for the presence of peaks in the electronic band structure near the Fermi energy. The measurement of the entropy loss during the transition from the nonsuperconducting to the superconducting state, a straightforward measurement...
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A new dilution-enrichment sample preparation strategy for expanded metabolome monitoring of human breast milk that overcomes the simultaneous presence of low- and high-abundance lipid species
PublikacjaThe complex nature of human breast milk (HBM) makes samples difficult to analyze, requiring several extraction techniques and analytical platforms to obtain high metabolome coverage. In this work, we combined liquid-liquid extraction (LLE) and solid-phase extraction (SPE) techniques to prepare HBM samples to overcome the challenge of low- and high-abundance lipid species, enabling the semiquantitative analysis of total HBM lipids...
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Synthesis of 3-indolylmethyl substituted (pyrazolo/benzo)triazinone derivatives under Pd/Cu-catalysis: Identification of potent inhibitors of chorismate mutase (CM)
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Synthesis of 11,12-dihydro benzo[c]phenanthridines via a Pd-catalyzed unusual construction of isocoumarin ring/FeCl3-mediated intramolecular arene-allyl cyclization: First identification of a benzo[c]phenanthridine based PDE4 inhibitor
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Cytotoxicity of doxorubicin conjugated with C60 fullerene. Structural and in vitro studies
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Solid phase extraction with flame atomic absorption spectrometry for determination of traces of Ca, K, Mg and Na in quality control of white sugar
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Bioaccessibility of Ca, Cu, Fe, Mg, Mn and Zn from commercial bee honeys
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Sensitive Determination of Cd in Small-Volume Samples by Miniaturized Liquid Drop Anode Atmospheric Pressure Glow Discharge Optical Emission Spectrometry
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Flowing Liquid Anode Atmospheric Pressure Glow Discharge as an Excitation Source for Optical Emission Spectrometry with the Improved Detectability of Ag, Cd, Hg, Pb, Tl, and Zn
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AGREE—Analytical GREEnness Metric Approach and Software
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Application of cold atmospheric pressure plasmas for high-throughput production of safe-to-consume beetroot juice with improved nutritional quality
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The Baltic Sea as a dumping site of chemical munitions and chemical warfare agents
PublikacjaW pracy przedstawiono problem składowania w Morzu Bałtyckim aminucji chemicznej i bojowych środków trujących. Przedstawiono typy oraz charakterystykę BST składowanych na dnie Morza Bałtyckiego. Omówiono potencjalne zagrożenia dla środowiska abiotytcznego oraz dla organizmów żywych związanych z tego typu składowiskami. Przedstawiono również podstawowe informacje o procedurach analitycznych, które mogą być wykorzystane do wykrywania...
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Influence of a lipid bilayer on the conformational behavior of amphotericin B derivatives - A molecular dynamics study.
PublikacjaAmphotericin B (AmB) is an effective but very toxic antifungal antibiotic. In our laboratory a series of AmB derivatives of improved selectivity of action was synthesized and tested. To understand molecular basis of this improvement, comparative conformational studies of amphotericin B and its two more selectivederivatives were carried out in an aqueous solution and in a lipid membrane. These molecular simulation studies revealed...
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Ion-selective electrodes based on p-tert-butyl-homooxacalixarene di(ethyl) amides
PublikacjaPochodne dietyloamidowe p-tert-butylodihomooksakaliks[4]arenu (1), p-tert-butyloheksahomotrioksakaliks[3]arenu (2) oraz p-tert-butylokaliks[4]arenu (3) były wykorzystane jako materiał aktywny w membranach elektrod jonoselektywnych w celu sprawdzenia detekcji kationów różnych rodzajów (Na+, K+, Cs+, Mg2+, Ca2+, Mn2+, Cu2+, Zn2+, Cd2+, Pb2+ oraz kation tetrametyloammoniowy). Wyznaczono charakterystyki elektrod oraz współczynniki...
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Direct conversion of secondary phosphine oxides and H-phosphinates with [di(acyloxy)iodo]benzenes to phosphinic and phosphonic amides
PublikacjaW publikacji przedstawiono metodę pozwalająca na bezpośrednie otrzymywanie amidów kwasu fosfinowego i fosfonowego w reakcji drugorzędowych tlenków fosfin lub H-fosfinianów z [di(acyloksy)iodo]benzenami w obecności amin pierwszo lub drugorzędowych. Wykorzytując silne acylujące właściwości układu [di(acyloksy)iodo]benzen/R2P(O)H.
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Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-Active Ligands
PublikacjaCoordination complexes that possess large magnetic anisotropy (otherwise known as zero-field splitting, ZFS) have possible applications in the field of magnetic materials, including single molecule magnets (SMMs). Previous studies have explored the role of coordination number and geometry in controlling the magnetic anisotropy and SMM behavior of high-spin (S = 3/2) Co(II) complexes. Building upon these efforts, the present work...
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Comparability of Raman Spectroscopic Configurations: A Large Scale Cross-Laboratory Study
PublikacjaThe variable configuration of Raman spectroscopic platforms is one of the major obstacles in establishing Raman spectroscopy as a valuable physicochemical method within real-world scenarios such as clinical diagnostics. For such real world applications like diagnostic classification, the models should ideally be usable to predict data from different setups. Whether it is done by training a rugged model with data from many setups...
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Proteolysis of whey protein isolates in nanoemulsion systems: impact of nanoemulsification and additional synthetic emulsifiers
PublikacjaNanoemulsions are currently of interest in the functional food sector because their small droplet size (100–500 nm) provides a number of potential advantages over conventional emulsions. This study concerned the behavior of nanoemulsions stabilized with whey proteins and two synthetic emulsifiers (Tween 80 and Croduret), and exposed to conditions simulating the human upper gastrointestinal tract. In particular, the effect of synthetic...
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Diphosphinoboranes as Intramolecular Frustrated Lewis Pairs: P–B–P Bond Systems for the Activation of Dihydrogen, Carbon Dioxide, and Phenyl Isocyanate
PublikacjaHerein, we present the first example of the activation of small molecules by P-B-P bond systems. The reactivity study involves reactions of two selected diphosphinoboranes, (tBu2P)2BPh (1’) and (Cy2P)2BNiPr2 (2), that differ in terms of their structural and electronic properties for the activation of dihydrogen, carbon dioxide, and phenyl isocyanate. Diphosphinoborane 1’ activates H2 under very mild conditions in the absence of...
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Unexpected Z/E isomerism of N-methyl-O-phosphothioyl benzohydroxamic acids, their oxyphilic reactivity and inertness to amines
PublikacjaThiophosphinoylation of N-methyl p-substituted benzohydroxamic acids using disulfanes (method A) or diphenylphosphinothioyl chloride (method B) provides only one conformer of the respective O-phosphothioyl derivative (Xray and NMR analysis). Undergoing the P-transamidoxylation reaction is an evidence of the reversibility of thiophosphinoylation. Only those products containing strong EWG substituents in the aroyl residue or bulky...
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Potential Skyrmion Host Fe(IO3)3: Connecting Stereoactive Lone-Pair Electron Effects to the Dzyaloshinskii-Moriya Interaction
PublikacjaMagnetic skyrmions, which are topologically distinct magnetic spin textures, are gaining increased attention for their unique physical properties and potential applications in spintronic devices. Here we present a design strategy for skyrmion host candidates based on combinations of magnetic spin, asymmetric building units having stereoactive lone-pair electrons, and polar lattice symmetry. To demonstrate the viability of the proposed...
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Non-volatile molecular composition and discrimination of single grape white of chardonnay, riesling, sauvignon blanc and silvaner using untargeted GC–MS analysis
PublikacjaThis study developed and applied a GC–MS method aiming at molecular fingerprinting of 120 commercial single grape white wines (Chardonnay, Riesling, Sauvignon Blanc and Silvaner) for possible authentication according to grape variety. The method allowed detection of 372 peaks and tentative identification of 146 metabolites including alcohols, organic acids, esters, amino acids and sugars. The grape variety effect explained 8.3%...
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Molecular Umbrellas Modulate the Selective Toxicity of Polyene Macrolide Antifungals
PublikacjaAntifungal polyene macrolide antibiotics Amphotericin B (AmB) and Nystatin (NYS) were conjugated through the ω-amino acid linkers with diwalled “molecular umbrellas” composed of spermidine-linked deoxycholic or cholic acids. The presence of “umbrella” substituents modulated biological properties of the antibiotics, especially their selective toxicity. Some of the AmB-umbrella conjugates demonstrated antifungal in vitro activity...
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Influence of different cultivation systems on bioactivity of asparagus
PublikacjaEvaluation of functional and bioactive compounds of Asparagus officinalis L. growing in conventional and organic greenhouse and conventional open –field farming was the aim of this research. Polyphenols in cladodes grown conventionally were higher than organic. Flavonoids and carotenoids were the highest in cladodes in open field. Organic spears were richer in total phenolics (+6.9% and +19.1%) and flavonoids (+4.7% and 16.8%)...
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Ab Initio Study of the Electronic Spectrum of 7-Hydroxyquinoline
PublikacjaThe electronic spectrum of 7-hydroxyquinoline has been studied by using ab initio Multi-State Multi-Reference Møller-Plesset Second-Order Perturbation Theory (MSMRMP2). The energy range up to 6.5 eV is taken into consideration. The lowest π–π* transition is calculated to have an energy of 3.65 eV in good agreement with experimental data. Several other π–π* transitions are predicted to have excitation energies of 4.93, 5.20, 5.47,...
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Unassisted formation of hemiaminal ether from 4-aminopyridine and o-vanillin - experimental and theoretical study
PublikacjaThe reactions between o-vanillin and three isomeric aminopyridines lead to imines of diverse spatial conformation and reactivity. The direct products of these simple reactions carried out in methanol are either imine compounds formed in the reactions of 2- amino- and 3-aminopyridine with o-vanillin or the α-aminoether formed in the reaction of o-vanillin with 4-aminopyridine. The Schiff-type derivative of 4-aminopyridine and o-vanillin,...
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Comparison of an Electronic Nose Based on Ultrafast Gas Chromatography, Comprehensive Two-Dimensional Gas Chromatography, and Sensory Evaluation for an Analysis of Type of Whisky
PublikacjaWhisky is one of the most popular alcoholic beverages. There are many types of whisky, for example, Scotch, Irish, and American whisky (called bourbon). The whisky market is highly diversified, and, because of this, it is important to have a method which would enable rapid quality evaluation and authentication of the type of whisky. The aim of this work was to compare 3 methods: an electronic nose based on the technology of ultrafast...
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Bacteriophages as Factories for Eu2O3 Nanoparticle Synthesis
PublikacjaThe use of phage display to identify peptides with an ability to bind and synthesize Eu2O3 nanoparticles is demonstrated in this report. This is the first report of modified phages specifically binding a lanthanide. The peptides exposed on virions revealed very strong binding to Eu2O3 nanoparticles and the ability to catalyze Eu2O3 nanoparticles’ formation from Eu(OH)3 and Eu(NO3)3 solutions. The luminescence emission spectrum...
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Antioxidant properties of ferrous flavanol mixtures
PublikacjaInteraction of metal, especially iron ions with flavanols is considered as an important feature of these compounds and is believed to contribute to their both antioxidant and prooxidant properties. The aim of this study was to examine how Fe2+ binding to form a 4:1 (flavanol:Fe2+) mixtures affects the antioxidant properties of flavanols. ABTS∗ scavenging, protection against fluorescence bleaching induced by AAPH and hypochlorite,...
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Antioxidants and proteins in ethylene-treated kiwifruits
PublikacjaW pracy porównano właściwości przeciwutleniające i profil białek owoców kiwi poddanych działaniu etylenu i powietrza. Wysokie współczynniki korelacji między całkowitą zawartością fenoli i właściwościami przeciwutleniającymi uzyskano dla trzech metod określania właściwości przeciwutleniających: ABTS, TEAC i CUPRAC. W paśmie białek owoców kiwi rozdzielonych za pomocą elektroforezy stwierdzono różnice w paśmie siarczanu dodecylu sodu...
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Applications of sample preparation techniques in the analysis of pesticides and PCBS in food
PublikacjaPestycydy oraz anality z grupy polichlorowanych bifenyli (PCB), można znaleźć w żywności w niewielkich stężeniach, jednak ich zdolność do kumulacji i toksyczność powodują konieczność oznaczanie tych związków w żywności. Analiza próbek żywności pod kątem obecności pestycydów i analitów z grupy PCB przysparza wiele trudności ze względu na specyfikę przygotowania próbki w oparciu o wieloetapowe operacje oczyszczania próbki zawierającej...
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Optimization of condition for demineralization Baltic cod (Gadus morhua) backbone
PublikacjaKręgosłupy dorsza bałtyckiego (Gadus morhua) są alternatywnym źródłem kolagenu. Aby uzyskać z nich natywny niezanieczyszczony kolagen należy usunąć z nich białka mięśniowe i sole mineralne. Obecność tych związków pogarsza funkcjonalne właściwości preparatu kolagenowego. Dlatego celem pracy było opracowanie optymalnych parametrów demineralizacji kręgosłupów dorsza. Najlepszy efekt demineralizacji, nieomal 100%, przy stratach tylko...
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The influence of different acids and pepsin on the extractability of collagen from the skin of Baltic cod (Gadus morhua)
PublikacjaZastosowano 5,0 M roztwory kwasu cytrynowego, mlekowego, octowego oraz 0,115 M roztwór kwasu solnego. Kolagen z całych skór ekstrahowano w 4 st.C odpowiednimi kwasami (1 : 6, w/v) w czasie 24, 48 i 72 h. Stwierdzono, że kwas solny jest najmniej efektywnym rozpuszczalnikiem kolagenu spośród użytych kwasów. W zastosowanych warunkach doświadczeń maksymalnie można wyekstrahować kwasem cytrynowym 60 % kolagenu, kwasem octowym i mlekowym...