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  • 1
    ISSN: 1432-1106
    Keywords: Vestibulo-ocular reflex ; Optokinetic nystagmus ; Vestibular habituation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1.Unilateral habituation of the vestibuloocular reflex was produced in adult cats stimulated by repeated unidirectional velocity steps (vestibular training) or by a continuously moving visual surround (optokinetic training). — 2. Unidirectional vestibular training produced a strong asymmetry of vestibuloocular responses (VOR). Responses to velocity steps applied to the “trained” labyrinth were decreased both in gain and in time-constant. This effect generalized to responses to sinusoidal oscillations (0.03 Hz to 0.1 Hz), i.e. to a stimulus not used during training. — No spontaneous nystagmus was ever observed in spite of the dynamic VOR asymmetry. — 3. Unilateral vestibular habituation produced by vestibular training appeared to be a long-lasting phenomenon. It was still present 10 days after the end of training. — 4. Optokinetic responses were not affected by vestibular training. — 5. Unidirectional optokinetic training produced an increase in the slow phase velocity of optokinetic nystagmus (OKN) by about 25% in both directions. This effect did not persist for more than a few minutes. A marked spontaneous nystagmus was recorded in the dark after each session of optokinetic training, with a slow phase in the direction opposite to the previous OKN. — 6. VOR in response to velocity steps and to sinusoidal oscillations were decreased unilaterally after optokinetic training. This effect was of short duration, however, and disappeared within the interval between training sessions. This lack of retention contrasted with the prolonged effect of vestibular training.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 28 (1977), S. 235-248 
    ISSN: 1432-1106
    Keywords: Vestibulo-ocular reflex ; Hemilabyrinthectomy ; Role of vision ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. A new description of vestibulo-ocular responses to angular velocity steps has been used to quantify vestibular compensation in right hemilabyrinthectomized cats. The amplitudes (VM and CM) and the times of occurrence (tM and to) from stimulus onset of the peaks of slow phase eye velocity and slow cumulative eye position were computed for velocity steps directed towards the lesioned side (clockwise, CW) and towards the intact side (counterclockwise, CCW). In addition, the values of these parameters were corrected from the effects of spontaneous nystagmus, when present. 2. In animals recovering in normal laboratory conditions, spontaneous nystagmus disappeared within 10 days after operation. In CCW responses, vm decreased by about 45% during the first 3 days and then remained stationary during the next 2 weeks. In CW responses VM showed a rapid increase during the first 3 days, and then remained stationary. After 2 weeks, VM increased in both CW and CCW responses. CM changes substantially reproduced those of VM. 3. In animals put in the dark immediately after operation, spontaneous nystagmus persisted until re-exposure to light (up to 31 days) and then disappeared rapidly. VM in both CW and CCW responses remained at a low value during the dark period and became more or less doubled after one week of exposure to light. CM also increased rapidly in CW and CCW responses, after re-exposure to light. 4. In the discussion these results are compared with those concerning activity of single vestibular neurons during compensation. It is concluded that vision is a primary factor conditioning disinhibition of vestibular nuclei spontaneous activity after the critical phase of compensation.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 162 (1927), S. 321-332 
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of Pentaazadienido Complexes of Copper(I) and Copper(II). Crystal Structures of [Cu(F—C6H4N5C6H4—F) (py)]2, [Cu(Cl—C6H4N5C6H4—Cl) (py)]2, [Cu(CH3O—C6H4N5C6H4—OCH3) (py)]2Cu(NH3)42+ reacts in conc. aqueous NH3 with RN2NHN2R to yield insoluble, brownish CuII pentaazadienido complexes Cu(RN5R)2 (R = p-F—C6H4, p-Cl—C6H4, p-MeO—C6H4). The dry compounds are explosiv. They decompose in hot THF or toluene under reduction of CuII to form the CuI complexes Cu(RN5R) from which upon addition of pyridine the dinuclear, red complexes [Cu(RN5R) (py)]2 (R = p-F—C6H4 (1), p-Cl—C6H4 (2) and p-MeO—C6H4 (3)) are obtained.1 crystallizes in two monoclinic modifications: I: P21/c; a = 1370.7(3), b = 1145,2(1), c = 2436.9(3) pm, β = 91.68(1)º, Z = 4, V = 3823.8 · 106 pm3, II: P21/n; a = 1448.2(3), b = 1102.2(1), c = 2276,8(3) pm, β = 102.55(1)º, Z = 4, V = 3547.5 · 106 pm3. 2 forms monoclinic crystals with the space group P21/c; a = 1095.6(6), b = 1820,2(6), c = 1007.5(3) pm, β = 114.12(3), Z = 2; 3 crystallizes monoclinic: P21/c; a = 1213.5(5), b = 1813.8(5), c = 990.0(3) pm, β = 116.76(2)º, Z = 2.The pentaazadienid ion functions in all complexes as bridging ligand with (N1)-η1, (N3)-η1 coordination, resulting in short Cu—Cu distances of 255.2 to 258.0 pm. The pyridine molecules are bound to the Cu atoms being in 1 in a cis and in 2 and 3 in trans arrangement with respect to the Cu—Cu axis.
    Notes: Cu(NH3)42+ reagiert in konz. wässerigem NH3 mit RN2NHN2R unter Bildung schwerlöslicher CuII-pentaazadienido-Komplexe Cu(RN5R)2 (R = p-F—C6H4, p-Cl—C6H4, p-MeO—C6H4). Die im trockenen Zustand explosiven Verbindungen zersetzen sich beim Erhitzen in THF oder Toluol unter Reduktion des Kupfers zu den CuI-Komplexen Cu(RN5R), aus denen mit Pyridin die zweikernigen, roten Komplexe [Cu(RN5R) (py)]2 (R = p-F—C6H4 (1), p-Cl—C6H4 (2) und p-MeO—C6H4 (3)) entstehen. 1 kristallisiert in zwei monoklinen Modifikationen. I: P21/c; a = 1370,7(3), b = 1145,2(1), c = 2436,9(3) pm, β = 91,68(1)º, Z = 4, V = 3823,8 · 106 pm3, II: P21/n; a = 1448,2(3), b = 1102,2(1), c = 2276,8(3) pm, β = 102,55(1)º, Z = 4, V = 3547,5 · 106 pm3. 2 bildet monokline Kristalle mit der Raumgruppe P21/c; a = 1095,6(6), b = 1820,2(6), c = 1007,5(3) pm, β = 114,12(3)º, Z = 2; 3 kristallisiert ebenfalls monoklin: P21/c; a = 1213,5(5), b = 1813,8(5), c = 990,0(3) pm, β = 116,76(2)º, Z = 2.Das Pentaazadienidion fungiert in allen Komplexen als Brückenligand mit (N1)-η1, (N3)-η1-Koordination, so daß kurze Cu—Cu-Abstände im Bereich von 255,2 bis 258,0 pm resultieren. Die Pyridinmoleküle sind an die Cu-Atome gebunden und in 1 bezüglich der Cu—Cu-Achse in cis- und in 2 und 3 in trans-Stellung angeordnet.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 354 (1967), S. 27-29 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The new quaternary compound LiBa2EuO4 may be prepared from stoichiometric amounts of LiEuO2 and BaO by heating at 700°C under an inert atmosphere. According to Debye-Scherrer photographs. LiBa2EuO4 and LiEu3O4 are isostructural (space group Pbnm). The orthorhombic unit cell with a = 11.883, b = 12.130 and c = 3.601 Å contains 4 formula units LiBa2EuO4 (calculated density 6.369 g/cm3).
    Notes: Die neue quaternäre Verbindung LiBa2EuO4 kann aus den stöchiometrisch erforderlichen Mengen LiEuO2 und BaO durch Erhitzen bei 700°C unter Schutzgas erhalten werden. Wie aus DEBYE-SCHERRER-Aufnahmen hervorgeht, ist LiBa2EuO4 mit LiEu3O4 isotyp (Raumgruppe Pbnm). Die rhombische Elementarzelle mit a = 11,883, b = 12,130 und c = 3,601 Å enthält 4 Formeleinheiten LiBa2EuO4 (berechnete Dichte 6,369 g/cm3).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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