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  • Polymer and Materials Science  (12)
  • Chemical Engineering  (5)
  • Cat  (3)
  • hypertension  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 86 (1991), S. 324-332 
    ISSN: 1432-1106
    Keywords: Vision ; Optokinetic nystagmus ; Eye movements ; Plaids ; Brainstem ; Motion perception ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have recorded the direction of optokinetic nystagmus (OKN) elicited by moving plaid patterns in order to dissociate the pathways that mediate horizontal OKN. The plaids used comprised two drifting sinusoidal gratings arranged such that their individual directions of drift were very different from the direction of coherent motion of the overall pattern. The direction of OKN with binocular viewing was close to the mean of the component directions, suggesting a dominant influence of cortical visual neurons that respond to oriented one-dimensional components of the image. But the direction of OKN was consistently shifted slightly towards the direction of motion of the overall pattern, suggesting a secondary influence responsive to pattern direction. OKN recordings obtained during monocular viewing suggest that this secondary influence reflects the direct retinal pathway to the brainstem structures mediating OKN.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 17 (1973), S. 315-332 
    ISSN: 1432-1106
    Keywords: Red nucleus ; Unit recording ; Motor cortex ; Topographical organization ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A topographical study of the cortico-rubrospinal pathway was conducted in cats anesthetized with chloralose. Extracellular unit recordings were made from cells in the red nucleus projecting to the spinal cord. They were identified by antidromic invasion following stimulation of their axones at the 2nd cervical and 9th thoracic levels of the spinal cord. I. The pericruciate cortical regions from which spikes could be induced in rubrospinal neurons were limited to the lateral part of the anterior sigmoid gyrus, the lateral sigmoid gyrus and the anterior part of the posterior sigmoid gyrus. No responses were obtained from stimulation of the medial part of the anterior sigmoid gyrus or the gyrus proreus. Compared to the somatotopic organization of the motor cortex for the cat described by Woolsey (1958), our results show that the rubrospinal cells receive projections from the motor cortex controlling proximal and distal muscles but not axial muscles. II. Neurons projecting to the cervico-thoracic cord receive afferents from the lateral part of the anterior sigmoid gyrus and the lateral sigmoid gyrus whereas those projecting to the lumbo-sacral cord receive projections from the entire surface of the sigmoid gyrus except the medial part of the anterior sigmoid gyrus and the gyrus proreus. III. A latero-medial organization of cells within the red nucleus was found according to the origin of their cortical afferents. Rubrospinal neurons with fibers terminating in the cervical or thoracic cord receive projections from the motor cortex controlling the proximal musculature of the forelimb when they are located in the dorso-lateral region of the nucleus and the entire forelimb motor cortex when they are located in the medial part of the nucleus. It is suggested that this organization may indicate a control of proximal forelimb musculature by dorsolateral rubrospinal cells and distal musculature by medial cells. IV. Rubrospinal cells placed medially in the nucleus receive more convergent projections (i.e. from a greater cortical surface) than cells placed more laterally. It was shown that for certain cells the convergence occurs in the direct pathway. These results are discussed in terms of a functional organization allowing coordinated movements of different segments of a single limb or of different limbs.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 60 (1985), S. 411-416 
    ISSN: 1432-1106
    Keywords: Vision ; Motion after-effects ; Cat ; Visual cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Responses of striate cortical neurones to bars of optimal orientation and width, moving with fixed velocity, were recorded in the lightly anaesthetized cat. Effects of periods of pre-adaptation with square-wave gratings of variable spatial frequency and velocity, drifting continuously in each cell's preferred or null directions, were investigated. Variations of cells' directional bias and responsiveness to oriented bars were assessed in relation to the degree and time-course of pre-adaptation to drifting gratings, compared with the preceding level of firing when exposed to uniform backgrounds of the same average luminance. All cells showed some susceptibility to pre-adapting moving gratings: subsequent responses to a bar were initially depressed in the direction of pre-adaptation and, in direction-biased or bidirectional cells, were enhanced in the opposite direction, compared with bar responses following exposure merely to a uniform background. These effects were strongest and most consistent amongst standard complex cells and weakest amongst special complex cells: maximal effects were obtained with adapting gratings of optimal velocity and spatial frequency.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1041
    Keywords: debrisoquine ; hypertension ; renin ; catecholamines ; platelet monoamine oxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The 24 h urinary excretion of adrenaline, noradrenaline, metadrenaline, normetadrenaline and vanillylmandelic acid, plasma renin activity and plasma and urinary debrisoquine were measured before and during chronic treatment with oral debrisoquine in 14 in-patients with essential hypertension. There was a significant fall (mean ±SD) in the 24 h urinary excretion of vanillylmandelic acid (15.3±2.8 to 6.7±1.9 µmol) noradrenaline (199.0±105.8 to 125.2±43.3 nmol) and plasma renin activity (0.71±0.47 to 0.40±0.20 pmol Angio I ml−1 h−1) while the urinary normetadrenaline/noradrenaline ratio increased (10.4±6.1 to 17.1±5.1). No significant change was seen in the output of adrenaline or of O-methylated metabolites. Debrisoquine produces extensive noncompetitive inhibition of platelet monoamine oxidase in vivo at low therapeutic plasma concentrations. These changes support the view that treatment with debrisoquine produces intraneuronal inhibition of monoamine oxidase and post-ganglionic blockage. There was a significant correlation between the change in standing diastolic blood pressure and the daily dose (rs=−0.52), pre-dose plasma concentration (rs=−0.85) and mean daily urinary recovery (rs=−0.80), of debrisoquine. The full extent of the biochemical changes were seen at low dose and low plasma concentration and were not directly correlated with the fall in standing or supine blood pressure.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 29 (1985), S. 33-36 
    ISSN: 1432-1041
    Keywords: cold sensitivity ; hypertension ; alpha- and beta-blockade
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The presence of cold sensitivity was investigated in three groups of patients; untreated hypertensives and hypertensives treated by a beta-adrenoceptor blocker (propranolol) or by a combined alpha-and beta-adrenoceptor blocker (labetalol) at two ambient temperatures. At a comfortable ambient (24°C) one-third of the untreated and those treated with beta-blockade only showed cold sensitivity as compared with 16% of patients on the combined therapy. Under conditions of mild cold stress (20°C) cold sensitivity increased in frequency in all three groups, more than half of the untreated and beta-blocked patients were affected and greater than one-third of those with alpha- and beta-blockade. These findings indicate that in the general population of hypertensives treatment with beta-adrenoceptor blockade alone may have little effect on the peripheral vasculature and that a useful degree of protection may be provided by therapy which blocks both receptors.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 14 (1978), S. 383-390 
    ISSN: 1432-1041
    Keywords: Acebutolol ; N-acetyl metabolite ; drug plasma concentrations ; plasma renin activity ; hypertension ; β-blockade
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Relationships between plasma concentrations of acebutolol (Ac) and its N-acetyl metabolite (Am) and pharmacological effects were studied in patients with essential hypertension. In an acute study (N=7) 400 mg oral acebutolol produced similar peak plasma levels of Ac and Am but Am had a longer half life. Group mean pulse and blood pressure fell significantly, although the size of individual blood pressure fall varied five-fold. There was no significant change in plasma renin activity. Correlations were found between drug concentration and β-blockade, assessed as % reduction in exercise tachycardia, and between both of these and the fall in post exercise systolic blood pressure. Similar comparisons were made in a chronic optimum dose study (N=11) both pre-dose and three hours post-dose. Am concentration was consistently higher than Ac at both times. Blood pressure was lowered equally pre-and post-dose when compared to placebo and plasma renin activity (PRA) was reduced on active treatment. Correlations were again shown between drug concentrations and β-blockade but none were found with changes in blood pressure or PRA. Between subject differences in blood pressure response could not be fully explained in terms of the other measurements but it is unlikely that pharmacokinetic differences are the major source of this variability.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 29 (1989), S. 433-440 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The flow of Newtonian and non-Newtonian fluids which obeys a power law relationship between shear stress and shear rate has been modeled in the melt conveying section of a self-wiping co-rotating twin-screw extruder using a finite element analysis of an unwound channel section. Predictions of throughput against pressure gradient are compared with experimentally obtained results for maize grits which is represented as a power law material. Rheological data applicable to extrusion simulation were obtained from capillary rheometry. Comparisons are reasonable with predicted characteristic showing similar behavior.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 40 (1994), S. 373-377 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 28 (1977), S. 405-409 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Chromverarmung nichtrostender Stähle beim Glühen im VakuumBei der selektiven Oxidation von Chrom in nichtrostenden Stählen wird das Oxidatinos-verhalten stark von den Veränderungen der Chromkonzentration an der Metalloberfläche und im Metall beeinflußt. Nach den bisherigen Annahmen verhält sich das Chrom bei der selektiven Oxidation ebenso wie bei der Verflüchtigung während des Vakuumerhitzens auf hohe Temperaturen. In der vorliegenden Arbeit wird die Verdampfung von Chrom aus Stahl 316 bei Vakuumanlassen bei 1000 °C mittels energiedispersiver Röntgenstrahlen- und Neutronenaktivierungsanalyse untersucht. Es wird festgestellt, daß der Chromverlust aus austenitischen nichtrostenden Stählen durch Interdiffusion in der Legierung kontrolliert wird. Entsprechend der Vorhersage nimmt die Chromkonzentration an der Metalloberfläche mit zunehmender Erhitzungsdauer ab. Das Chromverarmungsprofil im Metall stimmt gut über in mit einem früher obgeleiteten Modell, abgesehen von einer anomalen Zone in Oberflächennähe. Die hohe Auflösung der Neutronenaktivierungstechnik läßt erkennen, daß es sich um eine etwa 2μm dicke Zone handelt, wo die Chromkonzentration steiler absinkt als es den erwartungen entspricht.
    Notes: During selective chromium Oxidation of stainless steels the changes in chromium concentration at the metal surface and in the metal have an important bearing on the overall oxidation performance. It has been proposed that an analogue of chromium behaviour during selective oxidation is obtained from volatilisation of chromium during high temperature vacuum annealing. In the present report the evaporation of chromium from 316 type of steel, vacuum annealed at 1000 °C, has been investigated by menas of energy dispersive X-ray analysis and by neutron activation analysis. It was established that chromium loss from austenitic stainless steels is rate controlled by interdiffusion in the alloy. As predicted the chromium concentration at the metal surface decreased with increasing vacuum annealing time. The chromium depletion profile in the metal was in good agreement with the previously derived model apart from an anomalous region near the surface. Here the higher resolution of the neutron activation technique indicated a zone within ∼2μm of the surface where the chromium concentration decreased more steeply than expected.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 29 (1978), S. 246-250 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Konzentrationsprofile in einem Duplex-Oxidzunder auf Stahl 316Konzentrationsprofile in auf vakuumangelassenem Stahl 316 entstandenem Duplex-Oxidzunder wurden mit Neutronenaktivierungsanalyse und energiedispersiver Analyse untersucht. Gute qualitative Übereinstimmung zwischen den beiden Methoden ergab sich für das Konzentrationsprofil von Chrom in der äußeren Oxidschicht; die Ergebnisse deuten auf eine geringe Geschwindigkeit der Stromdiffusion in die äußere Magnetitschicht. Bei der inneren Oxidschicht ist die Übereinstimmung zwischen den beiden Methoden weniger gut, da die Ergebnisse der Neutronenaktivierung durch die Anwesenheit von Metall in der Querschnittsfläche verfälscht werden. Die Ergebnisse der energiedispersiven Analysen dieser Schicht stimmen mit früheren Befunden überein, wonach normale oder nichtselektive Oxydation auftritt.
    Notes: Concentration profiles through duplex scales formed on vacuum annealed 316 stainless steel have been investigated using neutron activation analysis and energy dispersive analysis. Good qualitative agreement between the two analytical techniques was obtained for chromium concentration profiles in the outer oxide. These indicated a low rate of chromium diffusion into the Fe3O4 layer. There was less agreement between the two methods in the inner oxide as the neutron activation results were complicated by the presence of metal in sections through this oxide layer. The energy dispersive results in this layer were consistent with previous findings which indicated conservative or non selective oxidation occurring.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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