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Wyniki wyszukiwania dla: FOLIN-CIOCALETU REAGENT
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The effect of heating and fermenting on antioxidant properties of white cabbage
PublikacjaIt is widely believed that natural antioxidants found in food are significantly lost during processing. Nevertheless, it was recently demonstrated that processed fruits and vegetables may retain their antioxidant activity. In the present work, the changes in the overall antioxidant properties as a consequence of fermentation of cabbage and/or heat treatment of cabbage juices and extracts were studied. Fermentation processes as...
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Application of a commercially available derivatization instrument and commonly used reagents to HPLC on-line determination of antioxidants
PublikacjaThis study demonstrates the potential of a commercially available derivatization instrument coupled with HPLC for separation and on-line determination of antioxidants detected with widely used screening reagents - DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) or FCR (Folin-Ciocalteu's phenol reagent ). As the result of optimization, key parameters of the analytical procedure,...
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The optimisation of analytical parameters for routine profiling of antioxidants in complex mixture by HPLC coupled post-column derivatisation
PublikacjaIntroduction: The wide application of natural and artificial antioxidants in food, cosmetic and pharmaceutical industry as well as the recognition of the importance of food antioxidants for supporting human health created demand for reliable and industrially applicable methods of determining antioxidative activity. This requirement can be fullfilled with the recently proposed HPLC-post-column derivatisation approach enabling the...
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New products of reaction of Lawesson's reagent with diols.
PublikacjaW artykule przedstawiono syntezę i szczegółową charakterystykę strukturalną i konformacyjną 8-, 9- i 10-członowych pierścieniowych związków heterocyklicznych o unikatowym układzie atomów O-P-S-S. W wyniku reakcji a,w-dioli z odczynnikiem Lawessona wobec zasad powstają odpowiednie sole kwasów bisditiofosfonowych, które po utlenieniu dają w/w pierścieniowe disulfidy. Kwasy bisditiofosfonowe przekształcono także w trwałe diestry S-metylowe,...
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Efficient reagent immobilization procedure for ion-sensitive optomembranes
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Mechanism of the reaction of Lawesson's reagent with N-alkylhydroxamic acids
PublikacjaIdentyfikacja fosforowych produktów powstających w reakcji kwasów hydroksamowych z odczynnikiem Lawessona pozwoliła ustalić mechanizm tytułowej reakcji. Wykorzystano w tym celu spektroskopię 31P NMR. Wzorce labilnych produktów otrzymano na niezależnej drodze syntetycznej lub przeprowadzono je w trwałe pochodne, które wyizolowano z mieszanin reakcyjnych. Produktem przejściowym badanej reakcji okazał się odpowiedni O-ditiofosfonylowany...
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1-(2-Pyridylazo)-2-naphthol as Possible Analytical Reagent
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A Novel [4+2] Cycloaddition Reaction Involving Lawesson’s Reagent. Structure and Specific Fragmentations of a New Cyclic 1,2-Thiaphosphinane-4-one
PublikacjaA crude morpholine enamine of acetone treated with Lawesson’s reagent unexpectedly yielded a six-membered thiaphosphinane-4-one. This compound is the first example of a new class of heterocycles. It has been proven that it is formed from 4-methyl-2-morpholino-1,3-pentadiene which is usually present in crude morpholine enamine batches. A mechanism of this regioselective reaction was postulated and a characteristic chair-like conformation...
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Decolorization of Congo red via hydrodynamic cavitation in combination with Fenton’s reagent
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Lawesson's reagent (LR) for direct thionation of hydroxamic acids. Substituent effect on LR reactivity
PublikacjaOkreślono zakres stosowalności i ogranicznia metody bezpośredniej tionacji kwasów hydroksamowych (HAA) za pomocą odczynnika Lawessona (LR). Przedmiotem badań było 35 HAA o wzorze ogólnym R1CON(R2)OH gdzie: R1 = alkil, aryl, benzyl, etoksykarbonylometylen, cynamyl, heteroaryl, a R2 = alkil, aryl. Ustalono, że wydajności kwasów tiohydroksamowych są niskie, gdy wyjściowy HAA posiada w swojej strukturze duże objętościowo reszty R1...
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A new silylation reagent dimethyl(3,3,3-trifluoropropyl)silyldiethylamine for the analysis of estrogenic compounds by gas chromatography–mass spectrometry
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Sequential Synthesis of Organosilicon‐Linked 2‐Methoxypyridines by Non‐Cryogenic ortho‐Metallation Using the nBu2TMPMg·Li Reagent and Hydrosilylation
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A new silylating reagent – dimethyl(3,3,3-trifluoropropyl)silyldiethylamine – for the derivatisation of non-steroidal anti-inflammatory drugs prior to gas chromatography–mass spectrometry analysis
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Microwave-assisted preparation of potato starch silicated with silicic acid
PublikacjaApplication of microwave irradiation for the silication of granular potato starch with silicic acid, and the properties of silicated starch were investigated. Potato starch was esterified on 20 min microwave irradiation of starch with silicic acid, applying the power of 450 or 800Wand, for comparison, on 120 min convectional heating of the reagent blend at 100 ◦C. The degree of esterification and the reaction efficiency did not...
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Zaawansowane utlenianie odcieków składowiskowych - przegląd metod
PublikacjaPrzedstawiono rozwiązania unieszkodliwiania odcieków składowiskowych metodami zaawansowanego utleniania, takimi jak: reakcja Fentona, utlenienie ozonem i nadtlenkiem wodoru, utlenienie elektrochemiczne, utlenienie w warunkach nadkrytycznych oraz mokre utlenienie powietrzem. Podstawy teoretyczne tych metod, ich efektywność oraz stosowane reagenty. Uwarunkowania stosowania poszczególnych metod.
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FTIR spectra of gas mixtures from the process of biogas dry reforming using Al2O3/5%Cu catalyst
Dane BadawczeThe dataset contains the FTIR spectra collected during the catalytic measurements of dry reforming of biogas (60/40 CH4-CO2) using AlOOH/1%Cu nanocatalyst. The specatra were collected every 1 minute from 800C to 500C. Reagent flow was set to 20ml/min.
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FTIR spectra of gas mixtures from the process of biogas dry reforming using CeO2/5%Cu catalyst
Dane BadawczeThe dataset contains the FTIR spectra collected during the catalytic measurements of dry reforming of biogas (60/40 CH4-CO2) using CeO2/5%Cu nanocatalyst. The specatra were collected every 1 minute from 800C to 500C. Reagent flow was set to 20ml/min.
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Control of mass concentration of reagents by sound in a gas with nonequilibrium chemical reactions
PublikacjaThe weakly nonlinear dynamics of a chemically reacting gas is studied. Nonlinear interaction of acoustic and nonacoustic types of motion are considered. We decompose the base equations using the relationships of the gas-dynamic perturbations specific for every type of motion. The governing equation for the mass fraction of a reagent influenced by dominating sound is derived and discussed. The conclusions concern the equilibrium...
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FTIR spectra of gas mixtures from the process of biogas dry reforming using Al2O3/5%Cu catalyst
Dane BadawczeThe dataset contains the FTIR spectra collected during the catalytic measurements of dry reforming of biogas (60/40 CH4-CO2) using Al2O3 (TMDAR)/5%Cu nanocatalyst. The specatra were collected every 1 minute from 800C to 500C. Reagent flow was set to 20ml/min.
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The antioxidant properties of anthocyanins in different Aronia products
PublikacjaOgromne znaczenie w patologii wielu chorób, w tym chorób układu krążenia oraz nowotworów, ma stan przewlekłego stresu oksydacyjnego. Podwyższonej produkcji reaktywnych form tlenu mogą zapobiegać naturalne przeciwutleniacze pochodzenia roślinnego. Z tego powodu przedmiotem badań w wielu ośrodkach naukowych na świecie są rośliny, których składniki charakteryzują się wysokim potencjałem przeciwutleniającym. Do takich roślin zalicza...
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The synthesis and structure of a potential immunosuppressant: N-mycophenoyl malonic acid dimethyl ester
PublikacjaThe 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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New conjugates of mycophenolic acid and their antiproliferative activity
PublikacjaThe new conjugates of mycophenolic acid (MPA) were obtained in the reaction of N6-(ω-aminoalkyl)adenosines with MPA in the presence of EDCI as a coupling reagent. New compounds 4a–h were evaluated on leukemia cell line (Jurkat) and PBMC from healthy donors. Length of the linker influenced observed activity. The compound 4b possessing 1,3-diamine spacer exhibited the most promising results and can be considered to further investigations.
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The overview of reactors used for the production of precipitated calcium carbonate via carbonation route
PublikacjaCarbonation is one of the methods for the production of precipitated calcium carbonate (PCC) on the industrial scale. A gaseous CO2 is used as a reagent in this process. The hydrodynamic conditions gener-ated in the reactor affect the course of the process and the characteristics of the precipitated calcium carbonate particles. This paper discusses the construction of standard reactors and new proposed con-struction used for the...
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Ring Opening of Triflates Derived from Benzophospholan-3-one Oxides by Aryl Grignard Reagents as a Route to 2‑Ethynylphenyl(diaryl)phosphine Oxides
PublikacjaA new simple method for the synthesis of 2-ethynylphenyl(diaryl)phosphine oxides via ring opening of benzophosphol-3-yl triflates has been developed. This process occurs via nucleophilic attack of a Grignard reagent at the phosphorus center, which results in ring opening and cleavage of a leaving group. The reaction proceeds under mild conditions and, within 15−60 min, leads to a library of previously unavailable 2-ethynylphenylphosphine...
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Factors causing degradation of sulfadimetoxine
PublikacjaSulfadimetoxine is a representative of sulfonamide drugs which presence inhibits growth of activated sludge bacteria, rhat is necessary for the effective mineralization of organic and inorganic contaminants. Therefore factors which con prevent this situation are searched. Aim of this study is selection of conditions causing efficien degradation of the drug- sulfadimetoxine. The impact of such aspects as : the type of oxidizing...
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Preparation of 1-[Ω-(1,4,5,6-Tetrahydropyrimidin-2-yl)alkyl]thymines
PublikacjaOne-stage prepn. of the hydrochloride salts of 1-[ω-(1,4,5,6-tetrahydropyrimidin-2-yl)alkyl]-thymines, e.g. I, from 1-(ω-cyanoalkyl)thymines and a 1:1-mixt. of 1,3-diaminopropane and ethanol satd. with hydrogen sulfide is described. 1-(2-Cyanoethyl)-thymine gave a facile reversal of the Michael reaction to thymine under the conditions used. The reaction of 1,3-bis(3-cyanobenzyl)thymine with the above reagent produced 1,3-bis[3-(1,4,5,6-tetrahydropyrimidin-2-yl)benzyl]thymine.
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Rheology of potato starch chemically modified with microwave-assisted reactions
PublikacjaNative potato starch was sulfated, selenated, borated, silicated and zincatated by means of microwave-assisted reactions with varying doses of relevant reagents. Resulting products were characterized involving rheological behavior of pastes, their weight-average molecular weight (Mw), and radius of gyration (Rg). Most of the pastes showed shear-thinning behavior, with the flow behavior index (n) below unity. The pastes of starch...
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Phenolic composition and antioxidant properties of polish blue-berried honeysuckle genotypes by HPLC-DAD-MS, HPLC postcolumn derivatization with ABTS or FC, and TLC with DPPH visualization
PublikacjaIn this study, different Polish cultivars of blue-berried honeysuckles (Lonicera caerulea L.), wild and bog bilberry, were analyzed for bioactive compounds. The chemical properties verified included composition of anthocyanins and other polyphenols, antioxidant activity, and profiles of antioxidants by HPLC postcolumn derivatization or TLC. The antioxidant activities of different blue-berried honeysuckle cultivars were similar...
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Common methods for the chiral determination of amphetamine and related compounds I. Gas, liquid and thin-layer chromatography
PublikacjaThis article reviews the most common, useful methods for the chiral determination of amphetamine (AM) and AM-deriveddesigner drugs in different of matrix, including blood, hair, urine, medicaments or standard solutions, taking into considerationarticles published in the past 15 years. We consider chromatographic methods (e.g., gas, liquid, high-performance liquid, and thinlayer). We describe several types of chiral derivatization...
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Impact of Cultivation Conditions, Ethylene Treatment, and Postharvest Storage on Selected Quality and Bioactivity Parameters of Kiwifruit “Hayward” Evaluated by Analytical and Chemometric Methods
PublikacjaOrganic, semiorganic, and conventional “Hayward” kiwifruits, treated with ethylene for 24 h and stored during 10 days, were assessed by UV spectrometry, fluorometry, and chemometrical analysis for changes in selected characteristics of quality (firmness, dry matter and soluble solid contents, pH, and acidity) and bioactivity (concentration of polyphenols via Folin-Ciocalteu and p-hydroxybenzoic acid assays). All of the monitored...
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Validated HPTLC method for determination of ledol and alloaromadendrene in the essential oil fractions of Rhododendron tomentosum plants and in vitro cultures and bioautography for their activity screening
PublikacjaRhododendron tomentosum (Ledum palustre) is a bog shrub used in traditional medicine for treatment of respiratory and rheumatic diseases. Due to the large variability of the chemical composition of its essential oil, depending on the habitat, the in vitro cultures were established as the alternative source of the volatile fraction. There is a need to monitor a quality of the field grown as well as in vitro plant material, especially...
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Liquefaction of macroalgae Enteromorpha biomass for the preparation of biopolyols by using crude glycerol
PublikacjaThis article describes the liquefaction process of macroalgae Enteromorpha with the use of crude glycerol as a solvent and a reagent, aimed at obtaining of new bio-polyols, which are characterized with respect to their chemical structure, physical and thermal properties. Six different biopolyols were prepared. In order to optimize the liquefaction of algal biomass for the best bio-polyol properties, two catalysts (sulfuric or orthophosphoric...
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Comparison of the content of phenolic compounds and antioxidant activity of white, red and black currants (Ribes sp.) extracts
PublikacjaThe aim of this study was to compare the content of antioxidant compounds and the antioxidant activity of extracts from white, red and black currants (Ribes sp.). The chemical properties verified included determinations of anthocyanins and other phenols by HPLC-DAD-MS, total antioxidant activity by standard spectrophotometric tests (ABTS, DPPH and FCR), and profiles of antioxidants by TLC with visualization reagents (ABTS, DPPH,...
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Meldrum’s acid assisted formation of tetrahydroquinolin‑2‑one derivatives a short synthetic pathway to the biologically useful scaffold
PublikacjaA new method for the preparation of tetrahydroquinolin-2-one derivatives is presented. This approach involves a two-step reaction between enaminones and acylating agents, immediately followed by electrophilic cyclization, all within a single synthesis procedure, eliminating the need to isolate intermediates. The entire process is facilitated by the use of acyl Meldrum’s acids which not only shortens the preparation time of the...
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Excitation of Non-Wave Modes by Sound of Arbitrary Frequency in a Chemically Reacting Gas
PublikacjaThe nonlinear phenomena in the field of high intensity sound propagating in a gas with a chemical reaction, are considered. A chemical reaction of A → B type is followed by dispersion and attenuation of sound which may be atypical during irreversible thermodynamic processes under some conditions. The first and second order derivatives of heat produced in the chemical reaction evaluated at the equilibrium temperature, density and...
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The influence of plant protection by effective microorganisms on the content of bioactive phytochemicals in apples
PublikacjaThe phytochemicals of two apple cultivars (Yellow Transparent and Early Geneva) protected in two ways, conventionally with chemical pesticides or by effective microorganisms (EM), were compared. Two types of components were determined: lipids synthesised constitutively and generated via inducible pathways polyphenols along with antioxidant activity and profiles. The antioxidant activities assessed with ABTS, DPPH and Folin–Ciocalteu...
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Thermal properties of strontium–borate glasses and glass-ceramics containing bismuth and vanadium oxides measured with DSC method
Dane BadawczeThermal properties of strontium–borate glasses and glass-ceramics containing bismuth and vanadium oxides was measured by DSC.
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Effect of Bi2O3 Excess on Morphology and Structure of BiNbO4 Ceramics
PublikacjaGoal of the present research was to fabricate BiNbO4 ceramics from the mixture of powders by the solid state reaction route and pressureless sintering at various temperatures (TS =8700C and TS =9100C) and study microstructure, phase composition and crystalline structure of BiNbO4 ceramics. Four batches were fabricated and examined, namely the one fabricated from the stoichiometric mixture of reagent – grade oxide powders, viz....
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A novel chemiluminescent immunoassay based on original acridinium ester labels as better solution for diagnosis of human toxoplasmosis than conventional ELISA test
PublikacjaToxoplasma gondii infection is one of the most common human zoonosis. Laboratory diagnosis of this disease is mainly based on the results of serological methods detecting specific antibodies in the patient’s sera. In this study we aimed to evaluate the performance of a chemiluminescence immunoassay (CLIA) based on the use of a novel immunochemical reagent in the form of the conjugate of original acridinium label (AL) attached to...
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TMSCL as a rate accelerating additive in acylations of amines with 5-(α- amino-α'-hydroxy)methylene meldrum's acids
PublikacjaAspects are presented of the acylation of amines, alcohols and thiols with 5-(α-amino- α'-hydroxy)methylene Meldrum's acids. We placed special emphasis on the acylation reaction of secondary amines with 5-(α-amino- α'-hydroxy)methylene Meldrum's acids, which, due to their basicity, caused problems concerning salt formation with a Meldrum acid derivative. We found that secondary amines, which react at the slowest rate and with a...
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Activation of the C=P bond in phosphanylphosphaalkenes C=P–P bond system) in the reaction with nucleophilic reagents: MeLi, nBuLi and tBuLi
PublikacjaThree reactions of phosphanylphosphaalkene (1) with nucleophiles were performed to activate the diphosphorus monomer. We observed similar results in the reactions with MeLi and nBuLi, in which the P–P bond is cleavaged and triphosphorus systems [P(Me)2–CH(biph)–CH(biph)–P–(PtBu 2)]- (1a'') and [P(nBu)2–CH(biph)–CH(biph)–P–(PtBu 2)]- (1b''), respectively, are formed depending on the nucleophilic reagent (biph ¼ biphenyl). In the...
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Metrics for green analytical chemistry
PublikacjaGreen analytical chemistry, although not being a new concept, does not have a greenness metrics system. Green chemistry metrics are not suitable for analytical procedure assessment because they often refer to the mass of the product. Some efforts have been made to develop suitable metrics for analytical chemistry. Some are simple to use but do not cover all aspects of analytical methods’ environmental impact. Others are more comprehensive...
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Tmscl as a rate accelerating additive in acylations of amines with 5-(α-amino- α'-hydroxy)methylene meldrum's acids
PublikacjaAspects are presented of the acylation of amines, alcohols and thiols with 5-(α-amino- α'-hydroxy)methylene Meldrum's acids. We placed special emphasis on the acylation reaction of secondary amines with 5-(α-amino- α'-hydroxy)methylene Meldrum's acids, which, due to their basicity, caused problems concerning salt formation with a Meldrum acid derivative. We found that secondary amines, which react at the slowest rate and with a...
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The XRD diffraction patterns of as-preapred (La0.3Sr0.6Ce0.1)0.9FexTi(1-x)O3-δ (x=0.1, 0.2 and 0.3) materials
Dane BadawczeThe (La0.3Sr0.6Ce0.1)0.9FexTi(1-x)O3-δ (x=0.1, 0.2 and 0.3) materials were synthesized via the Pechini method. First, the reagents in the form of nitrates were weighed and dissolved in DI water. In another beaker, a stoichiometric amount of titanium (IV) butoxide (Ti(OBu)4) was mixed together with reagent-grade ethylene glycol (EG), and citric acid...
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The XRD diffraction patterns of as-prepared (La0.3Sr0.6Ce0.1)0.9Me0.1Ti0.9O3-δ (Me= Co, Fe, Ni) materials
Dane BadawczeThe (La0.3Sr0.6Ce0.1)0.9Me0.1Ti0.9O3-δ (Me= Co, Fe, Ni) materials were synthesized via the Pechini method. First, the reagents in the form of nitrates were weighed and dissolved in DI water. In another beaker, a stoichiometric amount of titanium (IV) butoxide (Ti(OBu)4) was mixed together with reagent-grade ethylene glycol (EG), and citric acid (CA)...
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The XRD diffraction patterns of as-prepared (La0.3Sr0.6Ce0.1)0.9Ni0.05Me0.05Ti0.9O3-δ (Me= Co, Fe, Cu) materials
Dane BadawczeThe ((La0.3Sr0.6Ce0.1)0.9Ni0.05Me0.05Ti0.9O3-δ (Me= Co, Fe, Cu) materials were synthesized via the Pechini method. First, the reagents in the form of nitrates were weighed and dissolved in DI water. In another beaker, a stoichiometric amount of titanium (IV) butoxide (Ti(OBu)4) was mixed together with reagent-grade ethylene glycol (EG), and citric acid...
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The XRD diffraction patterns of as-prepared (La0.3Sr0.6Ce0.1)0.9FexMeyTi(1-x-y)O3-δ materials (Me=Ni,Co)
Dane BadawczeThe (La0.3Sr0.6Ce0.1)0.9FexMeyTi(1-x-y)O3-δ materials (Me=Ni,Co) were synthesized via the Pechini method. First, the reagents in the form of nitrates were weighed and dissolved in DI water. In another beaker, a stoichiometric amount of titanium (IV) butoxide (Ti(OBu)4) was mixed together with reagent-grade ethylene glycol (EG), and citric acid (CA)...
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Linear impedance of strontium–borate glass measured with impedance spectroscopy method at low temperature region
Dane BadawczeThe linear electrcial properties of strontium–borate glass was measured by impedance spectroscopy method.
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Characterization of white cabbages from different cultivations by isothiocynates content and antioxidant activities
PublikacjaBadania epidemiologiczne wskazują, że wraz z zwiększeniem spożywania kapusty maleje ryzyko zachorowania na niektóre nowotwory. Mechanizmy przeciwrakotwórczego działania nie są do końca wyjaśnione, jednak wiele badań przeprowadzonych z wykorzystaniem zwierząt i ludzi sugeruje, że substancje występujące w tych roślinach, szczególnie izotiocyjaniany (ITC) modulują aktywność enzymów I i II fazy. Aktywność przeciwutleniająca jest innym...
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Dispersive Micro‐Solid Phase Extraction of Selected Metals in Water and Food Samples Followed by ICP‐OES Analysis: Method Development, Analysis of Real Samples and Greenness Evaluation
PublikacjaMultiwalled carbon nanotubes (MWCNTs) are well-known adsorbents because of their high surface area, layered and hollow architecture, hydrophobicity, and multiple and easily accessible adsorption sites. In this study, MWCNTs were used for dispersive micro-solid-phase extraction of various metal chelates in environmental and food samples. Different parameters such as concentration of the chelating reagent, the sorbent dosage, the...