163 research outputs found
Multiple cutaneous and hepatic infantile hemangiomas having a successful response to propranolol as monotherapy at neonatal period
No full textInfantile hepatic hemangioma (IHH) is a common liver tumors of infancy with a higher incidence in females. Various treatments for infantile hepatic hemangioma such as systemic corticosteroids, interferon-alpha, vincristine and cyclophosphamide have been suggested, though no consensus exists about the first-choice treatment. Recent evidences suggest that propranolol, a nonselective β-blocker, may be effective and safe as first-line therapy for infantile hepatic hemangioma. We report a case of female born at term with a weight of 2.450 g started to develop multiple cutaneous IHs at 10 days of age and presenting concomitant multiple cutaneous and hepatic infantile hemangiomas confirmed on magnetic resonance imaging. Propranolol, used as monotherapy, was started at 14 days of age at a dose of 2 mg/kg/day orally and maintained for 6 months. Patient was monitored in the hospital during first days of treatment with propranolol, and discharged after no side-effects were detected. Hepatic and cutaneous lesions had complete resolution in three months, although the fibro-fatty residuum of largest cutaneous nodule was still palpable at month 6. A further control after 6 months showed no recurrences. Our report case suggests that propranolol can be a safe and effective first-line therapy for neonates with concomitant multiple cutaneous and hepatic infantile hemangiomas
Twist grain boundary liquid-crystalline phases under the effect of the magnetic field: a complete 2H and 13C NMR study
No full textA liquid crystal (HZL7/*) containing an (S)-2-methylbutyl-(S)-lactote unit in the chiral chain, is investigated by means of H-2 and C-13 NMR spectroscopy in order to obtain information on its orientational order, its molecular structure and the effect of external magnetic fields on the supramolecular structure of its phases. This mesogen presents very peculiar mesomorphic properties and exhibits frustrated TGBA* and TGBC* phases in a wide temperature range up to 60 degrees C, as well as an additional phase transition from TGBC(1)* to TGBC(2) *. H-2 NMR measurements show, for the first time, a peculiar magnetic field effect in unwinding the supramolecular structure of both the TGBA* and TGBC* phases. This effect is particularly evident at higher magnetic fields, while different behaviour is observed at lower magnetic fields. This indicates that the supromolecular structure is very sensitive to magnetic fields of the order of 1 Tesla. Moreover, the analysis of the H-2 and C-13 NMR spectra of HZL 7/* allow us to obtain several structural properties, such as the tilt angle of the TGBC* phases and the local orientational order parameters referred to the phenyl and biphenyl fragments. This is the first structural characterization of the frustrated phases of these complexes by means of NMR
1H NMR relaxometry in the TGBA* and TGBC* phases
No full textRecent results obtained by 1H NMR relaxometry of liquid crystals having twist grain boundary (TGB) phases are here reviewed. In
particular, three chiral rod-like lactate derivative mesogens were investigated. In the isotropic phase, three-exponential magnetization
decay was observed in all cases and the three distinct spin-lattice relaxation times (T1) were assigned to three specific molecular groups
of these molecules. In the TGBA* and TGBC* phases the magnetization decay is mono-exponential and the main features of the 1H NMR
dispersion curves analyzed through a global target fitting procedure in terms of specific molecular and collective dynamics are discussed
Synthesis and mesomorphic properties of new compounds exhibiting TGBA and TGBC liquid crystalline phases
No full textWe synthesised a series of rod-like mesogens with a (S)-2-methylbutyl-(S)-lactate unit in the chiral chain that exhibited extremely wide temperature ranges in the TGBA and TGBC* phases. TGB phases were identified, based on typical textures in confined samples and in free-standing films, by Grandjean-Cano texture and by NMR studies on a deuterium-labelled isotopomer. A sufficiently high electric or magnetic field transformed the TGBA and TGBC* phases into their respective SmA and SmC* phases, the TGB structures being restored within some 20-30 minutes. Therefore values of the spontaneous polarisation and spontaneous tilt angle, when measured under a sufficiently high field, gave evidence of the properties of the SmC* phase. Temperature dependencies of relaxation frequency, dielectric strength, selective reflection and layer spacing showed anomalies at a certain temperature within the TGBC* phase range. Also, changes in textures, as well as in 2H-NMR spectra, occurred at this same temperature. These results suggest the existence of two TGBC* phases
Studies on oxidation of ergot alkaloids: oxidation and desaturation of dihydrolysergol-stereochemical requirements
No full textA new method for the oxidation of ergoline alcohols to aldehydes was found (TFFA-DMSO, -78 °C, then DIPEA). Structural features of ergolines required for successful C7-C8 double bond introduction via Polonovski-Potier reaction of respective 6-N-oxides were defined and experimentally confirmed: (i) the presence of electron-withdrawing group at C-8; (ii) trans-diaxial orientation of N6-O and C7-H bonds (both requirements are fulfilled for dihydrolyserg-17-al and its 2,4-dinitrophenyl hydrazone prepared in this work)
Direct Measure of the Tilt Angle in de Vries-Type Liquid Crystals through NMR Spectroscopy
No full textcommunication
Keramika Heleny Johnové výstava ze sbírek uměleckoprůmyslového odboru MG v Brně ; květen - červen 1981 ; kabinet užitého umění Moravské galerie v Brně
No full text1H NMR Relaxometric Study of Molecular Dynamics in a “de Vries” Liquid Crystal
No full textLiquid crystals that exhibit de Vries smectic A phases are promising materials for new generations of ferroelectric liquid crystal displays and other electro-optical devices. We investigated the molecular dynamic properties of a rod-like de Vries liquid crystal compound, namely the 9HL, a (S)-hexyl lactate derivative, in the whole mesophasic range. This is the first molecular dynamics’ investigation on a de Vries phase, and the interest of this system is related to the understanding of the structural and supramolecular organization of de Vries SmA phases, which has been a subject of a broad scientific debate in the last years. Proton NMR spin–lattice relaxation times, T1, were measured in the range 100 MHz to 5 kHz, thus covering a very wide range of motional regimes. 1H NMR dispersion curves and temperature-dependent relaxation rates were analyzed with a global minimum target fitting approach and the main molecular motions, namely reorientational diffusion, translational self-diffusion, layer undulation, and tilting director fluctuations were fully characterized. The molecular dynamics’ behavior observed across the SmA–SmC* phase transitions of 9HL was consistent with the proposed cluster diffuse cone model for the de Vries SmA phase
Nektere aplikace maticove analyzy.
No full textThesis submitted were created during my post - graduate study at the Masaryk University of Brno. In the work there are some applications of matrices analysis mentioned (it is one of the subject of interests of my supervisor Prof. RNDr. Ladislav Skula, DrSc.) The introductory part of the work deals with historical background of studied theory together with basic information about all chapters. In the first chapter some basic concepts of the theory of structures, hyperstructures and matrices are summarised. In the second chapter the solution of the matrices equation A=BC-CB over the Galois points for quadrate matrices (n=3 and n=4) are described. The problem was solved both theoretically and numerically on PC. Third chapter deals with construction of the set of mutually commutable matrices solved for n=2 and 3. The matrix of homogeneous system for arbitrary natural numbers is presented. By trying to solve the matrix we obtained elements mutually commutable matrices mentioned above. Fourth chapter is devoted to complex matrices A+iB, where A,B are quadrate real matrices n-th row with positive elements. Two hyperoperations defined on monounary algebra(Mreg,d) and their properties are mentioned also. The application of matrices calculus in the theory of linear regression is discussed in the fifth chapter together with solution of two examples.Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi
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