170 research outputs found

    Galanin hatása a vazopresszin kiválasztásra patkányba

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    The 29 amino acid-containing galanin isolated from the porcine intestine is known to play a significant role in the regulation of the function of the hypothalamo-neurohypophyseal system. The basal vasopressin concentration was examined, and also those vasopressin levels following osmotic and non-osmotic stimuli after centrally administered galanin. The effects of rat, porcine and human galanin and the human galanin 1-16 fragment on vasopressin release were studied. Finally, the question was investigated of whether the galanin receptor antagonist galantid (M15) was able to prevent the vasopressin level changes induced by galanin. Galanin administered intravenously did not influence the vasopressin excretion. After the intracerebroventricular (i.c.v.) injection of galanin, the vasopressin level decreased and the enhancement of the plasma vasopressin concentration following intraperitoneal 2.5% NaCI solution or histamine administration was significantly moderated. There was no essential difference in the vasopressin release effects of rat, porcine and human galanins. The human galanin 1-16 fragment proved to be active as concerns vasopressin regulation. Galantid administered i.c.v. before the galanin injection prevented all of the vasopressin- responsive effects of galanin. The results indicate that galaninergic control is of great importance in the regulation of vasopressin secretion

    Observation of conduction electron spin resonance in boron doped diamond

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    We observe the electron spin resonance of conduction electrons in boron doped (6400 ppm) superconducting diamond (Tc =3.8 K). We clearly identify the benchmarks of conduction electron spin resonance (CESR): the nearly temperature independent ESR signal intensity and its magnitude which is in good agreement with that expected from the density of states through the Pauli spin-susceptibility. The temperature dependent CESR linewidth weakly increases with increasing temperature which can be understood in the framework of the Elliott-Yafet theory of spin-relaxation. An anomalous and yet unexplained relation is observed between the g-factor, CESR linewidth, and the resistivity using the empirical Elliott-Yafet relation.Comment: 10 pages, 11 figures, submitted to Phys. Rev.

    Grape (Vitis vinifera) seeds from Antiquity and the Middle Ages Excavated in Hungary - LM and SEM analysis

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    Grape (Vitis vinifera) seed remains were excavated at Roman and Medieval archeological sites in Hungary and analyzed by LM (Light Microscopy) and SEM (Scanning Electron Microscopy). Excavation sites included Budapest (Aquincum; 2nd - 4th CENT. A.D. Hungary) and Keszthely (Fenékpuszta) of the Roman Age (5th CENT. A.D., Hungary); and Gyır (Ece; 11-12th CENT. A.D., Hungary), Debrecen (13th CENT. A.D., Hungary) and the King’s Palace of Árpád Dinasty at the Castle of Buda, Budapest (15th CENT. A.D., Hungary) of the Middle Ages. Ancient seeds were compared to thirty current grape varieties of similar seed size, shape, and morphology (Szabó et al. 2007´). The modern grape variety Vitis vinifera cv. ‘kék bakator’ (syn.:‘Blue Bocca d’Oro’; ‘aranybogyó’) was found most similar in seed morphology to one of the ancient samples (15th CENT. Debrecen, Hungary) which indicates the antiquity of this cultivar

    Correlation between microstructure and temperature dependence of magnetic properties in Fe 60 Co 18 ( Nb , Zr ) 6 B 15 Cu 1 alloy series

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    Temperature dependence of magnetic properties of nanocrystalline Fe60Co18Cu1B15Nb6−xZrx (x =0, 3, 6) alloys has been studied at different stages of devitrification. Transmission electron microscopy shows nanocrystals of the size �5 nm, which remains almost constant along the nanocrystallization process. Curie temperature of the residual amorphous phase decreases as nanocrystallization progresses for all the studied alloys. Thermal dependence of the exchange stiffness constant is obtained from the measurement of specific magnetization and coercivity as a function of crystalline fraction and temperature for the three studied alloys

    Magnetic resonance in the antiferromagnetic and normal state of NH_3K_3C_60

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    We report on the magnetic resonance of NH_3K_3C_60 powders in the frequency range of 9 to 225 GHz. The observation of an antiferromagnetic resonance below the phase transition at 40 K is evidence for an antiferromagnetically ordered ground state. In the normal state, above 40 K, the temperature dependence of the spin-susceptibilty measured by ESR agrees with previous static measurements and is too weak to be explained by interacting localized spins in an insulator. The magnetic resonance line width has an unusual magnetic-field dependence which is large and temperature independent in the magnetically ordered state and decreases rapidly above the transition. These observations agree with the suggestion that NH_3K_3C_60 is a metal in the normal state and undergoes a Mott-Hubbard metal to insulator transition at 40 K.Comment: 4 pages, 5 figures. Submitted to Phys. Rev.
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