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1
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Growth and EPR properties of ErVO4single crystals

100%
Leniec G., Kaczmarek S. M., Berkowski M., Głowacki M., Skibiński T., Bojanowski B.
Nukleonika
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2015
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vol. 60
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issue 3
405-410
EN
Single crystals of ErVO4 were grown by the Czochralski method under ambient pressure in a nitrogen atmosphere. Obtained crystals were transparent with strong pink coloring. Electron paramagnetic resonance (EPR) spectra were recorded as a function of the applied magnetic field. Temperature and angular dependences of the EPR spectra of the samples in the 3–300 K temperature range were analyzed applying both Lorentzian––Gauss approximation for diluted medium and Dyson for dense magnetic medium. EPR-NMR program was done to find local symmetry and spin Hamiltonian parameters of erbium ions.
2
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Dyson line and modified Dyson line in the EPR measurements

100%
Popovych V., Bester M., Stefaniuk I., Kuzma M.
Nukleonika
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2015
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vol. 60
|
issue 3
385-388
EN
The difficulty in determining the electron paramagnetic resonance (EPR) line parameters of ferromagnetic semiconductors has been addressed. For these materials, the resonance line is very broad and lies at low resonance field, so that only a part of the line can be detected experimentally. Moreover, the line is of asymmetric (Dysonian) shape as described by the line shape parameter α. We have compared values of line parameters derived by computer fitting of the whole experimental EPR line to the Dyson function (or modified Dyson function) with the values obtained by applying this procedure to the left and the right half of the line.
3
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Effect of microwave power on EPR spectra of natural and synthetic dental biocompatible materials

100%
Adamczyk J., Ramos P., Pilawa B.
Nukleonika
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2015
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vol. 60
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issue 3
449-453
EN
Paramagnetic centers in the two exemplary synthetic and natural dental biocompatible materials applied in implantology were examined by the use of an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. The EPR spectra were measured in the range of microwave power 2.2–70 mW. The aims of this work were to compare paramagnetic centers concentrations in different dental biocompatible materials and to determine the effect of microwave power on parameters of their EPR spectra. It is the very first and innovatory examination of paramagnetic centers in these materials. It was pointed out that paramagnetic centers existed in both natural (~1018 spin/g) and synthetic (~1019 spin/g) dental biocompatible materials, but the lower free radical concentration characterized the natural sample. Continuous microwave saturation of EPR spectra indicated that faster spin-lattice relaxation processes existed in synthetic dental biocompatible materials than in natural material. Linewidths (ΔBpp) of the EPR spectra of the natural dental material slightly increased for the higher microwave powers. Such effect was not observed for the synthetic material. The broad EPR lines (ΔBpp): 2.4 mT, 3.9 mT, were measured for the natural and synthetic dental materials, respectively. Probably strong dipolar interactions between paramagnetic centers in the studied samples may be responsible for their line broadening. EPR spectroscopy is the useful experimental method in the examination of paramagnetic centers in dental biocompatible materials.
4
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X-Ray and EPR study on copper (II) complexes with an enamine ligand

100%
Ahmedova A., Vaz M., Ciattini S., Gochev G., Caneschi A., Mitewa M.
Open Chemistry
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2005
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vol. 3
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issue 1
146-156
EN
The enamine (HEAID) obtained from aniline and 2-acetyl-1,3-indandione (2AID) behaves as a bidentate ligand in coordination with copper (II) ion. Two types of crystals, apparently different in shape, were isolated and studied by single-crystal X-ray diffraction. The X-ray data for the brown rhombic crystals of compound 1 shows a mononuclear complex of Cu(II) coordinated with two EAID-anions, Cu(EAID)2. The X-ray data for the green crystals of compound 2 shows a dinuclear Cu(II) complex with two OH− groups acting as bridging ligands, [Cu2(μ-OH)2(EAID)2]. In both cases the ligand coordinates after deprotonation of the amine group.
5
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EPR and optical properties of KYb(WO4)2 and KTb0.2Yb0.8(WO4)2 single crystals

100%
Kaczmarek S., Macalik L., Fuks H., Leniec G., Skibiński T., Hanuza J.
Open Physics
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2012
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vol. 10
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issue 2
492-499
EN
Well oriented KYb(WO4)2 and KTb0.2Yb0.8(WO4)2 single crystals have been investigated for their magnetic and optical properties using the Raman and EPR techniques. The registered EPR signal is dominated by three lines ascribed to ytterbium ions: one main and two satellites. Tb ions, although non-paramagnetic, distinctly modify magnetic properties of the KYb(WO4)2 single crystal. Basic parameters of the spin Hamiltonian, including Zeeman and hyperfine terms (g and A matrices) as well the spatial orientation between principal and crystallographic axes systems were determined for both crystals.
6
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Growth and EPR properties of KSm(WO4)2 and KEr(WO4)2 single crystals

100%
Leniec G., Skibiński T., Kaczmarek S., Iwanowski P., Berkowski M.
Open Physics
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2012
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vol. 10
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issue 2
500-505
EN
Growth conditions and electron paramagnetic resonance investigations of two well oriented KSm(WO4)2 and KEr(WO4)2 single crystals have been presented and discussed. Hyperfine structure of Sm3+ ion was detected and analyzed for angular and temperature dependences. EPR spectra of KEr(WO4)2 and its angular dependence showed the presence of 5 magnetically nonequivalent Er centers in the crystal. A change in the type of magnetic interactions was analyzed using mixed (Gaussian and Lorentzian) fits of the EPR spectra.
7
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Wolne rodniki w dymie tytoniowym – metody analizy i znaczenie biomedyczne

100%
Kośmider L., Knysak J., Gawron M., Czogała J., Goniewicz M. Ł.
Medycyna Środowiskowa - Environmental Medicine
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2013
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vol. 16
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issue 3
7-14
EN
Free radicals, i.e. atoms or groups of atoms containing one or more unpaired electrons, are significant constituents of tobacco smoke that contribute to its toxic properties. Radicals are generated during complex pyrolysis and combustion reactions in burning a cigarette cone. It has been shown that some free radicals found in tobacco smoke have relatively long half-time life (over 5 mins). We have reviewed modern analytical methods used for identification and quantitative analysis of free radicals in tobacco smoke, particularly the electron paramagnetic resonance combined with a spin-trapping approach. We also discussed the role of free radicals in etiology of respiratory and cardiovascular conditions among smokers. Finally, we reviewed biochemical mechanisms of various pathological conditions, including disturbances in lipid peroxidation, activity modification of lecithin-cholesterol acyltransferase and level high density lipoprotein, hyperactivity to substance P, and inactivation of neutral endopeptidase, that are thought to be contributed by free radicals from tobacco smoke.
PL
Wolne rodniki – atomy lub grupy atomów, zawierające jeden lub więcej niesparowanych elektronów, są jednym z wielu czynników odpowiedzialnych za toksyczne właściwości dymu tytoniowego. Rodniki powstają w wyniku procesów spalania oraz procesów pirolizy, zachodzących w stożku żarzenia w trakcie wypalania papierosa. Niektóre rodniki występujące w dymie tytoniowym mają względnie długi okres półtrwania (ponad 5 min.). W niniejszej pracy omówiono nowoczesne metody analityczne służące do identyfikacji i ilościowej analizy wolnych rodników w próbkach dymu tytoniowego, ze szczególnym uwzględnieniem elektronowego rezonansu paramagnetycznego, w połączeniu z metodą pułapkowania spinowego. W pracy dokonano przeglądu istniejących poglądów na temat roli wolnych rodników w etiologii określonych chorób układu krążenia i układu oddechowego u palaczy, a także potencjalnych mechanizmów biochemicznych odpowiedzialnych za różne stany patologiczne (zaburzenia procesów peroksydacji lipidów, modyfikacje struktury i aktywności acylotransferazy lecytyna:cholesterol i poziomu lipoproteiny wysokiej gęstości, nadwrażliwość na substancję P i inaktywację obojętnej endopeptydazy).
8
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Microwave saturation of EPR spectra of oxidised coal

100%
Pilawa B., Więckowski A., Pietrzak R., Wachowska H.
Open Chemistry
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2007
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vol. 5
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issue 1
330-340
EN
Microwave saturation of multi-component EPR spectra of oxidized lignite Mequinenza (Spain) with a carbon content of 65.1 wt % and with a high sulphur content of 10.3 wt % was studied. The coal was oxidized with nitric acid (NHO3), peroxyacetic acid (PAA), and in O2/Na2CO3 system. Three different groups of paramagnetic centres exist in the coal samples analyzed. The EPR spectrum of the demineralised coal was a superposition of broad Gauss (ΔB pp = 0.75 mT), broad Lorentz 1 (ΔB pp = 0.42 mT) and narrow Lorentz 3 lines (ΔB pp = 0.08 mT). The three EPR components with linewidths: 0.58–0.77 mT (Gauss line), 0.30–0.39 mT (Lorentz 1 line) and 0.05–0.06 mT (Lorentz 3 line) were recorded for the oxidized coal. The g-values were obtained for the samples studied in the ranges 2.0043–2.0046 (Gauss lines), 2.0035–2.0038 (Lorentz 1 lines) and 2.0032–2.0034 (Lorentz 3 lines). The broad Gauss and Lorentz 1 lines saturate at low microwave powers. The narrow Lorentz 3 lines of demineralised coal were not saturated at microwave power from the range considered. After the coal oxidation with HNO3, PAA and in O2/Na2CO3 system, the microwave saturation of the narrow Lorentz 3 lines was also observed, which indicated a degradation of the multi-ring aromatic structures upon oxidation. [...]
9
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Synthesis, characterization and spectroscopic properties of some 2-substituted 1,3-indandiones and their metal complexes

88%
Ahmedova A., Atanasov V., Marinova P., Stoyanov N., Mitewa M.
Open Chemistry
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2009
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vol. 7
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issue 3
429-438
EN
New 2-acyl-1,3-indandione derivatives, compounds 1–4, were obtained by condensation of 2-acetyl-1,3-indandione with benzaldehyde, thiophene-2-aldehyde, thiophene-3-aldehyde and furane-2-aldehyde, respectively. The structures of the newly synthesized 2-substituted 1,3-indandiones were characterized by means of spectroscopic methods (FT-IR, 1H and 13C NMR, UV-Vis and MS). Based on the obtained results it is suggested that the compounds exist in the exocyclic enolic form. Mass spectral fragmentation paths are also proposed. In order to verify the possibility for tautomerization processes of the newly synthesized compounds their absorption spectra were recorded in various solvents. Furthermore, the complexation properties of the compounds with metal(II) ions were also studied. A series of non-charged complexes with Cu(II), Cd(II), Zn(II), Co(II) and Ni(II) was isolated and analyzed by elemental analyses and IR. The paramagnetic Cu(II) complexes were studied by EPR and distorted, flattened tetrahedral structures are predicted. The other metal complexes show the presence of water molecules, most probably coordinated to the metal ion, thus forming octahedral geometry. Ultimately, the studied properties of the newly synthesized compounds, 1–4, suggest that they may find application as extracting agents for metal ions, rather than as optical sensors. [...]
10
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Effect of microwave power on EPR spectra of thermally sterilizedeucerinum anhydricum

88%
Ramos P., Pepliński P., Pilawa B.
Nukleonika
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2015
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vol. 60
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issue 3
439-442
EN
Free radicals formed during thermal sterilization of eucerinum anhydricum – the pharmaceutical base were examined by an X-band (9.3 GHz) spectrometer. Eucerinum anhydricum was sterilized at different physical conditions according to the Polish Pharmacopeia norms. The samples were heated at temperatures: 160°C (120 min), 170°C (60 min), and 180°C (30 min). The aim of this study is to compare free radical concentration and effect of microwave power on EPR spectra of eucerinum anhydricum base thermally sterilized at different temperatures and periods of time. The effect of time storage on the free radicals in the heated samples was tested. Free radical concentrations in the sample stored 15 min strongly decreased with the increasing of sterilization temperature, probably as the result of recombination. Storage caused strong decrease of free radical concentrations in the samples, probably as the result of interactions with oxygen. It was observed to be independent of sterilization conditions from 2 days of storage and longer. Because of the lowest free radical concentration, for eucerinum anhydricum thermal sterilization at 180°C for 30 min is recommended. The sterilized samples should be stored at inert atmosphere without oxygen molecules. Fast spin-lattice relaxation processes existed in sterilized eucerinum anhydricum. The character of changes of amplitudes and linewidths of EPR lines with increasing of microwave power was the same for different storage times. The parameters of thermal sterilization and storage time influenced free radical concentration in eucerinum anhydricum, but magnetic spin-lattice interactions were unchanged. The usefulness of EPR spectroscopy in optimization of thermal sterilization process of eucerinum anhydricum was confirmed.
11
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Low temperature synthesis and characterization of Mn3O4 nanoparticles

88%
Baykal A., Köseoğlu Y., Şenel M.
Open Chemistry
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2007
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vol. 5
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issue 1
169-176
EN
Heating hydrous manganese (II) hydroxide gel at 85 °C for 12 hours produces Mn3O4 nanoparticles. They were characterized by X-ray powder diffraction (XRD) and infrared spectroscopy (FTIR). The particle size estimated from the SEM and X-ray peak broadening is approximately 32 nm, showing them to be nanocrystalline. EPR measurements confirm a typical Mn2+signal with a highly resolved hyperfine structure. [...]
12
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Callitriche cophocarpa - a new rich source of active phenolic compounds

88%
Augustynowicz J., Długosz-Grochowska O., Kostecka-Gugała A., Leja M., Kruczek M., Świderski A.
|
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issue 4
519-527
EN
This study was focused on the analysis of the contents (by HPLC-DAD) and antioxidant activity of phenolic compounds of aquatic higher plant Callitriche cophocarpa. The novelty of the work was: 1) the study of the species which is almost unknown in the context of investigations of bio-active compounds and, 2) the application of a unique L-band electron resonance spectroscopy (L-band EPR) to measure antioxidant activity of samples. The results were compared with those obtained for microalgae Chlorella and Spirulina which are widely distributed as the diet supplements. The obtained results are very promising with respect to the freeze-dried material of Callitriche, which revealed both high level of phenolic compounds (33 mg g−1 dry weight) and antioxidant activity (0.14 g of reduced DPPH· g−1 dry weight). An isoform of sinapic acid appeared to be the main fraction in this sample. The average content of the total phenolic compounds in Callitriche freeze-dried samples was ca. 43 or 25 times higher than in the case of the Chlorella or Spirulina samples, respectively. These samples showed also 16 times lower scavenging activity in relation to freeze-dried Callitriche material.
13
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THE RADIOSTABILITY OF BETAMIPRON IN THE SOLID STATE

88%
Zalewski P., Kilińska K., Cielecka-Piontek J., Skibiński R., Miklaszewski A., Bednarski W.
Acta Poloniae Pharmaceutica - Drug Research
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2019
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vol. 76
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issue 4
629-634
EN
The influence of ionising radiation on physicochemical properties of betamipron in solid state was studied. No changes for betamipron irradiated with a dose of 25 kGy, required to attain sterility, was observed by spectroscopic and chromatographic methods. Solid betamipron has proven to be very stable on irradiation, and irradiation has been found to be a suitable method for its sterilization.
14
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Splenic melanosis in agouti and black mice

88%
Michalczyk-Wetula D., Wieczorek J., Płonka P.
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issue 3
457-463
EN
An interesting example of extradermal deposition of melanin in vertebrates, notably in mammals, is splenic melanosis. In particular, if the phenomenon of splenic melanosis is correlated with hair or skin pigmentation, it must reflect the amount and perhaps the quality of pigment produced in hair follicle melanocytes. The present paper is our first study on splenic pigmentation in mice of phenotype agouti. We used untreated mixed background mice C57BL/6;129/SvJ (black - a/a, agouti - A/a, A/A), and as a control - black C57BL/6 and agouti fur from 129/SvJ mice, Mongolian gerbils (Meriones unguiculatus) and golden hamsters (Mesocricetus auratus). After euthanasia skin and spleen was evaluated macroscopically, photographed and collected for further analysis using Fontana-Masson and hematoxylin-eosin staining and electron paramagnetic resonance (EPR) at X-band. Spleens of the agouti mice revealed splenic melanosis but were slightly weaker pigmented than their black counterparts, while the presence of pheomelanin was difficult to determine. The fur of both phenotypes was of similar melanin content, with the same tendency as in the spleens. The contribution of pheomelanin in the agouti fur was on the border of detectability by EPR. Histological and EPR analysis confirmed the presence of melanin in the melanotic spleens. The shape of the EPR signal showed a dominance of eumelanin in fur and in melanized spleens in both phenotypes of mice. Therefore, splenic melanosis does reflect the hair follicle pigmentation not only in black, but also in agouti mice.
15
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Synthesis, characterization, catalytic and antimicrobial studies of ruthenium(III) complexes

88%
Thilagavathi N., Jayabalakrishnan C.
Open Chemistry
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2010
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vol. 8
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issue 4
842-851
EN
Ru(III) complexes of the type [RuXB(L)2] have been prepared by the reaction of 3,4-dihydropyrimidin-2(1H)-ones/thiones (HL1–HL4) with the precursors of the type [RuX3B3] where X=Cl or Br; B=PPh3 or AsPh3 and L is the deprotonated ligand. The synthesized complexes were characterized by physico-chemical methods, electrochemical and magnetic moment data. The catalytic efficiency of the complexes were examined in the oxidation of alcohols and antimicrobial studies were also carried out. [...]
16
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Taurine-EVA copolymer-paraffin rods dosimeters for EPR high-dose radiation dosimetry

88%
Maghraby A. M., Mansour A., Abdel-Fattah A. A.
Nukleonika
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2014
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vol. 59
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issue 1
9-13
EN
Taurine/EPR rods (3 × 10 mm) have been prepared by a simple technique in the laboratory where taurine powder was mixed with a molten mixture of paraffin wax and an ethylene vinyl acetate (EVA) copolymer. The binding mixture EVA/Paraffin does not present interference or noise in the EPR signal before or after irradiation. The rods show good mechanical properties for safe and multi-use handling. An EPR investigation of radiation induced radicals in taurine rods revealed that there are two types of radicals produced after exposure to gamma radiation (60Co). EPR spectra were recorded and analyzed - also the microwave power saturation and modulation amplitude were studied and optimized. Response of taurine to different radiation doses (1.5-100 kGy) was studied and found to follow a linear relationship up to 100 kGy. Radiation induced radicals in taurine persists and showed a noticeable stability over 94 days following irradiation. Uncertainities associated with the evaluation of radiation doses using taurine dosimeters were discussed and tabulated. It was found that taurine possesses good dosimetric properties using EPR spectroscopy in high doses in addition to its simple spectrum.
17
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Synthesis, characterization and magnetic investigation of (NH4)0.5Mn1.25(H2O)2[BP2O8]·0.5H2O

88%
Birsöz B., Baykal A., Toprak M., Köseoglu Y.
Open Chemistry
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2007
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vol. 5
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issue 2
536-545
EN
A new borophosphate compound with the composition (NH4)χ Mn((3−χ)/2)(H2O)2 [BP2O8]·(1−x)H2O was prepared under mild hydrothermal conditions and characterized by X-ray powder diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) methods. The title compound was synthesized from MnCl2·2H2O, H3BO3, and (NH4)2HPO4 with variable molar ratios by heating at 180 °C for 7 days in an autoclave. The X-ray diffraction data of the water insoluble polycrystalline powder was indexed using the TREOR program in hexagonal system with the unit cell parameters of a = 9.5104, c = 15.7108 Å, Z = 6 and the space group P65 (No.176). (NH4)χ Mn((3−χ)/2)(H2O)2 [BP2O8]·(1−x)H2O is isostructural with (NH4)χ M ((3−χ)2)/II (H2O)2 [BP2O8]·(1−x)H2O (MII = Co, Cd, Mg; x = 0.5–1). Its unit cell parameters and hkl values were in good agreement with the other isostructural compounds. This is the first report presenting both the synthetic details and the indexed X-ray powder diffraction pattern of this compound along with the characterization by FTIR, thermal gravimetric analysis, scanning electron microscopy and EPR. [...]
18
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Growth, optical and EPR properties of Li1.72Na0.28Ge4O9 single crystals pure and slightly doped with Cr

88%
Jasik A., Berkowski M., Kaczmarek S., Suchocki A., Kaminska A., Leniec G., Nowakowski P., Domukhovski V.
Open Physics
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2012
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vol. 10
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issue 2
506-513
EN
Single crystals of lithium-sodium-tetragermanate, a member of the solid solution series Li2−xNaxGe4O9 with x=0.28, pure and slightly doped with Cr3+ ions (0.03 mol.% and 0.1 mol.%), were grown in ambient atmosphere by the Czochralski technique from stoichiometric melt. The crystals with dimensions up to 20 mm in diameter and 50 mm in length were obtained. The crystal structure has been determined by means of X-ray diffraction. Phase analysis and structural refinement of the Li1.72Na0.28Ge4O9 crystals were performed by X-ray powder diffraction using Ni-filtered Cu Kα radiation with a Siemens D5000 diffractometer. The absorption, excitation and photoluminescence spectra of the crystals were measured in the UV-VIS and IR range at low temperatures. EPR investigations were performed using a conventional X-band Bruker ELEXSYS E 500 CW-spectrometer operating at 9.5 GHz with 100 kHz magnetic field modulation. Temperature and angular dependences of the EPR spectra of the crystal samples were recorded in the 3–300 K temperature range.
19
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Strategy of Cr detoxification by Callitriche cophocarpa

88%
Augustynowicz J., Kołton A., Baran A., Kostecka-Gugała A., Lasek W.
Open Chemistry
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2013
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vol. 11
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issue 2
295-303
EN
The present work focused on the qualitative and quantitative analysis of Cr detoxification strategy of aquatic cosmopolitan plant Callitriche cophocarpa. This plant species has just been described in the context of its unusual accumulation potential of Cr. The emphasis of the work was placed on the redox reaction Cr(VI)→Cr(III) which is considered to be remediation mechanism of highly reactive and mobile Cr(VI) ions. Plants were immersed for 5 days in 1 mM of Cr(VI) (potassium dichromate) or 1 mM of Cr(III) (chromium sulphate) solutions in semi-natural conditions. Cr was effectively removed from the solution up to the extent of ca.58% or 35% of the starting amount, in the case of Cr(III) and Cr(VI), respectively. No plant-induced Cr(VI) reduction accompanying Cr accumulation was observed in Cr(VI) solutions except from the apparent one, noticed at the fourth day of incubation. On the contrary to these results, according to the method of electron paramagnetic resonance spectroscopy (L-band EPR), biphasic signal of Cr(V) attending Cr(VI) to Cr(III) reduction was detected inside the plant tissue every day of investigations. Our results show that phytoextraction but not phytostabilization is the main strategy of Cr detoxification by C. cophocarpa in aquatic systems. [...]
20
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Security of Electronic Patient Record using Imperceptible DCT-SVD based Audio Watermarking Technique

88%
Kanhe A., Gnanasekaran A.
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issue 1
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