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  • 1
    Electronic Resource
    Electronic Resource
    Effect of acetazolamide on cerebral artery blood velocity and regional cerebral blood flow in normal subjects (1989)
    Springer
    Acta neurochirurgica 97 (1989), S. 139-145 
    Details
    ISSN: 0942-0940
    Keywords: Acetazolamide ; blood velocity ; cerebral blood flow ; normal subjects ; transcranial Doppler ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of intravenous acetazolamide L g on cerebral artery blood velocity and regional blood flow (rCBF) was investigated in eight normal subjects. Blood velocity was measured with 2 MHz pulsed Doppler in the proximal segments of the middle, anterior and posterior cerebral artery (MCA, ACA, and PCA) and in the distal extracranial internal carotid artery (ICA). The rCBF in the regions of interest tentatively corresponding to the perfusion territories of these vessels was estimated using133Xe inhalation and a rapidly rotating single photon emission computer tomograph. Both blood velocity and rCBF increased after acetazolamide. There was no significant difference between the percentage ICA blood velocity increase (22 ± 12%) and the percentage rCBF increase in the ICA region of interest (25 ± 9%). In the MCA, ACA, and PCA, however, blood velocity increased more (mean increase 36–42%) than the rCBF in the corresponding regions of interest (mean increase 24–26%). These differences were highly significant suggesting a direct and site specific effect of acetazolamide in narrowing the lumen of the proximal MCA, ACA, and PCA, but not of the extracranial ICA. We also propose that the effect of acetazolamide induces reciprocal changes in the extent of adjacent perfusion territories in individual brain hemispheres. Data compiled from all subjects investigated at two very different perfusion levels (before and after acetazolamide) revealed a significant positive correlation between blood velocity and rCBF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01772826
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  • 2
    Electronic Resource
    Electronic Resource
    Blood velocity and regional blood flow in defined cerebral artery systems (1989)
    Springer
    Acta neurochirurgica 97 (1989), S. 47-52 
    Details
    ISSN: 0942-0940
    Keywords: Cerebral artery blood velocity ; transcranial Doppler ultrasound ; regional cerebral blood flow ; normal subjects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cerebral artery blood velocity and regional blood flow (rCBF) were investigated in 17 normal subjects. Blood velocity was measured with 2 MHz pulsed Doppler ultrasound in the proximal segments of the middle, anterior and posterior cerebral artery (MCA, ACA, and PCA) and in the distal extracranial internal carotid artery (ICA). The rCBF in the regions of interest tentatively corresponding to the perfusion territories of these vessels was estimated using133Xe inhalation and a rapidly rotating single photon emission computer tomograph. Concomitant capnograph recordings showed that the end-expiratory pCO2 was higher during the rCBF than during the blood velocity examinations. This difference was highly significant. While there was no significant correlation between blood velocity and rCBF when these clear differences in pCO2 were disregarded, we did find significant positive correlations when the data were normalized to a standard pCO2 (5.3 kPa) using accepted formulas. The best correlation was found for the MCA (r=0.630, p〈0.001) and the PCA (r=0.73, p 〈 0.001), with a lower correlation in the ACA (r=0.49, p〈0.01) and the ICA (r=0.41, p〈0.05). The estimated blood velocity (V) given rCBF=0 was not significantly different from 0. The results support the validity of expressing the relationship between blood velocity (V) and rCBF in defined cerebral artery systems as: V=1/60(rCBF) T (A)−1, where A represents the area of the lumen of the vessel segment where the velocity is being measured, and T denotes the size of the brain region being perfused from this artery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01577739
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation of a pure autologous biodegradable fibrin matrix for tissue engineering (2000)
    Springer
    Medical & biological engineering & computing 38 (2000), S. 686-689 
    Details
    ISSN: 1741-0444
    Keywords: Tissue engineering ; Autologous fibrinogen ; Thrombin ; Matrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Parallel to the growing role of tissue engineering, the need for cell embedding materials, which allow cells to stabilise in a three-dimensional distribution, has increased. Although several substances have been tested, fibrin is thus far the only one that permits the clinical application of cultured tissue. To date, can cause severe immunological side effects. The objective of this study was to explore the practicability of obtaining autologous thrombin from a single patient in an adequate concentration and amount. Fibrinogen was cryoprecipitated from 200 ml of freshly-frozen plasma. Thrombin was isolated from the supernatant through ionexchange chromatography. The thrombin was first bound to Sephadex A-50 and then eluated using 2ml of a salt buffer (2.0M NaCl in 0.015M trisodiumcitrate, pH 7.0). The activity of the thrombin (51 NIH ml−1 to 414 NIH ml−1) reached levels comparable to those in commercially available fibrin glues (4–500 NIH ml−1). The study has shown that it is possible to obtain a sufficient amount of autologous thrombin from a single donor to create a fibrin matrix of high efficiency without the risk of immunological and infectious side effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02344876
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  • 4
    Electronic Resource
    Electronic Resource
    In vitro synthesis of polyribonucleotides (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 10 (1968), S. 359-372 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Polyribonucleotide: orthophosphate nucleotidyl transferase, commonly known as polynucleotide phosphorylase catalyzes the reversible polymerization of ribonucleoside diphosphates with the liberation of orthophosphate. The equilibrium constant is approximately 1.0. Although isolated from a variety of sources, the enzyme occurs essentially as two types: one which does not require a primer for reaction initiation and a second which does. A parallel study of an E. coli preparation representing the first type and an M. lysodeikticus preparation representing the second showed differences other than the primer requirement. Rates of polymerization were different as were the Kms. The E. coli preparation catalyzed the synthesis of polyguanylic acid while the M. lysodeikticus preparation did not although synthesis of hetoropolymers containing guanylic acid was catalyzed by the M. lysodeikticus enzyme. Use of repurified commercial substrates made the validity of some primer-requirement experiments suspect. End group analysis of product polymers served only to raise questions concerning the reaction-initiating compounds and the reaction mechanism. A study of hetero-polymer synthesis showed not only that the rate of polymerization was different, from that of homopolymers but that uncompetitive inhibition rather than competitive inhibition occurred when two ribonucleoside diphosphates were present in the reaction mixture. Furthermore, the experiments showed a preferential uptake of one substrate over another and an “enrichment” which was constant. It has also been shown that RNA polymerase, a DNA-RNA directed polymerase, can be used to synthesize polyribonucleotides if the appropriate template is provided.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260100309
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  • 5
    Electronic Resource
    Electronic Resource
    Rayleigh instability of stationary phase films in capillary column chromatography (1987)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 10 (1987), S. 128-136 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns ; Coating of capillaries, static and dynamic ; Rayleigh instability ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The film of stationary phase on the wall of a capillary column and that of the phase solution during both static and dynamic coating is subject to Rayleigh instability, which is quite independent of so-called wettability. A theory is developed which shows that the logarithmic growth rate of Rayleigh instabilities is proportional to the surface tension and to the third power of the film thickness, and inversely to the viscosity and to the fourth power of the capillary diameter. Determination of the variation of the viscosities of stationary phase solutions with concentration in coating solvents, and the variation of the viscosities of neat stationary phases with temperature, both revealed that heating and/or diluting changed the viscosities of phases with π-electron-containing, groups much more than for polydimethylsiloxanes. Rayleigh instability is therefore more important during coating of phenyl-containing phases such as OV-17, and later during column operation. The efficiencies of capillary columns of different diameters coated with a number of phases under different conditions of temperature and coating rate, and then operated at different temperatures were in good agreement with the predictions of the theory.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240100305
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  • 6
    Electronic Resource
    Electronic Resource
    Flow measurement engineering handbook by R. W. Miller, McGraw Hill Book Company, 960 pages, $59.95 (1984)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 30 (1984), S. 702-703 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690300438
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  • 7
    Electronic Resource
    Electronic Resource
    Observations of early turbulence in the pipe flow of drag reducing polymer solutions (1972)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 18 (1972), S. 213-217 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Early turbulence has for the first time been observed in the flow of very dilute polymer solutions in tubes larger than capillary size. Flow rate-wall shear stress measurements were conducted in 0.553 and 0.660 cm. diameter pipes. Polyethylene oxide samples of two molecular weights were employed, dissolved in water-glycerine mixtures with viscosities ranging from 0.0261 to 0.160 poise. The flow rate-wall shear stress relationship for these solutions corresponded to Poiseuille's Law below a well-defined onset wall shear stress, at which the Reynolds number was less than the transition value for Newtonian fluids. As the flow rate was increased from the onset condition, however, the wall shear stress became progessively larger than that predicted by the Poiseuille relationship. The onset wall shear stress for the phenomenon increased linearly with solvent viscosity. Its relationship to polymer concentration was dependent on the solvent viscosity. An explanation for early turbulence is suggested on the basis of these results, and the relationship of the phenomenon to turbulent flow drag reduction is discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690180139
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  • 8
    Electronic Resource
    Electronic Resource
    Stability of laminar pipe flows of drag reducing polymer solutions in the presence of high-phase-velocity disturbances (1973)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 19 (1973), S. 298-304 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A theoretical study of high-phase-velocity disturbances in the laminar pipe flow of drag-reducing polymer solutions is reported. These disturbances are found to be more stable in a polymer solution with a sufficiently small relaxation time than in a Newtonian fluid. The opposite effect is predicted when the relaxation time exceeds a critical value, however. These results are shown to be consistent with a hydrodynamic instability explanation of the early turbulence phenomenon.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690190214
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  • 9
    Electronic Resource
    Electronic Resource
    Bestimmung der Äquivalentgewichte organischer Säuren in krystallisiertem Zustand (1931)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 130 (1931), S. 1-10 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19311300101
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  • 10
    Electronic Resource
    Electronic Resource
    The effect of carbon black on thermal antioxidants for polyethylene (1959)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 1 (1959), S. 37-42 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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: About 3% by weight of carbon black adequately protects polyethylene against photo-oxidation and, under accelerated test conditions, slightly inhibits thermal oxidation. As a rule small amounts of organic antioxidants are also added to the polymer for optimum protection. Now many of the common phenolic and amine additives have been found to function much less effectively in polyethylene containing carbon black than in clear polymer. Loss of effectiveness is attributed to adsorption and/or decomposition of the antioxidant by both basic and acidic carbon black.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1959.070010107
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