Narcyz Piślewski

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Magnetic resonance imaging has been used to monitor the hydration of hydroxypropylmethylcellulose samples by two-dimensional mapping of properties such as spin density and relaxation times. The measurements were performed at two pH values of water: 2 and 6 and two temperatures 25 and 37 degrees C. It is shown that transport behavior of water into HPMC(More)
Magnetic resonance imaging was used to study the behavior of the gel layer thickness in hydroxypropyl methyl cellulose (HPMC) matrices loaded with different amounts of soluble tetracycline hydrochloride. The time dependence of the diffusion front, effective T2, and proton-density analysis clearly indicates a Case II diffusion mechanism in the system(More)
Proton magnetic resonance (1H magnetic resonance imaging (MRI)) images of human trabecular bone were acquired and discussed for two samples with different porosity. Three-dimensional 3D Spin Echo (3D SE) and Multi-Slice Multi-Echo (MSME) pulse sequences were examined. A very high slice resolution of (38 microm)2 was achieved (MSME). The intensity histograms(More)
The proton spin-lattice relaxation times in natural and partially deuterated ammonium hexachlorotellurate have been measured. At high temperature (above 50 K) the relaxation curve reveals the classical, hindered reorientation of the ammonium ion with the same activation energy for all studied samples Ea = 5.6 kJ/mol. Below 50 K, the minima which appear in(More)
Molecular motions and phase transition in [N(CH3)2H2]3Sb2I9 was studied by measuring the temperature dependencies of the proton spin-lattice relaxation times T1 and the second moment M2. The results are interpreted in terms of the C'3 reorientation of the methyl groups and the whole cationic reorientation about the C2 axis. The activation parameters for(More)
The 1H relaxation times T1 of methylammonium in chlorobismuthate(III) were measured in the temperature range from 50 to 270 K with a SXP 4/100 Bruker pulse spectrometer at 55.2 MHz. It was found that the T1 temperature dependence has three minima. The individual relaxation rates of the three-proton groups can be described by the O'Reilly and Tsang formula.(More)
Proton spin-lattice relaxation times (T1) have been measured as a function of temperature for the following catecholamines: dopamine hydrochloride and adrenaline hydrochloride. For both substances a single symmetric minimum of T1 is observed which can be explained as a result of NH3 (dopamine) and CH3 (adrenaline) reorientation around the three-fold axis of(More)
Human uterine muscle and its nuclear fractions have been studied by means of nuclear magnetic resonance at temperatures from 300 degrees K to 143 degrees K. Different proton populations have been detected above and below the freezing point. On this basis it is suggested that the freezing of water in uterine muscle starts at the cell nuclei.
The proton nuclear magnetic resonance (NMR) second moment and spin-lattice relaxation time for polycrystalline bis-n-propylammonium pentabromoantimonate (nPBA) have been measured from 70 to 290 K. The results are interpreted in terms of the CH3 and NH3 group reorientations for which the activation parameters have been determined. A structural phase(More)