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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 3 (1969), S. 699-710 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A generalization of a theorem on off-diagonal hypervirial relations is obtained and is used to demonstrate when to expect exact solutions of eigenvalue problems using the hypervirial method. Links are established between the hypervirial method and other approximation methods. The harmonic oscillator and hydrogen atom problems are given as examples.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 6 (1964), S. 247-270 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of ambient pressure and ultrasonic power on the disintegration of yeast suspension have been investigated. The results obtained are, in the main, consistent with the theory that cell breakage is primarily a phenomenon dependent on producing gaseous cavitation in the medium. The importance of the experimental results and techniques applied to Commercial cell disintegrators is briefly discussed. A simple flow system is described which is easily attached to probe-type disintegrators. The use of a crystal pickup for tuning and control purposes is described.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solutions of calf thymus DNA have been degraded in the presence of vibrating air bubbles in ultrasonic fields of low power which would not normally induce ultrasonic cavitation. The DNA was degraded to a limiting intrinsic viscosity, after which further irradiation by ultrasound had little or no effect. This limiting intrinsic viscosity decreased with increase in the ultrasonic intensity. Previously developed theories have-been adapted to calculate the maximum velocity gradient associated with the streaming of the solution around such vibrating air bubbles. The tensile force which is induced and which acts on the DNA has been calculated on the basis of current theories of degradation by hydrodynamic shear. These calculations indicate that the degradation of the DNA by ultrasound under conditions of “stable cavitation” is mainly the result of the shearing forces engendered in the solution around the oscillating bubbles.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 14 (1972), S. 33-42 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The release constant, k, of brewers yeast sonicated at powers up to 200 W at 20 kHz has been shown to be independent of cell concentration up to values of 60 g made up to 100 ml. It is inversely proportional to the volume of the treatment vessel in the range 75 to 450 ml, and almost proportional to the input acoustic power from 60 to 195 acoustic watts. A flow system is described and a relationship linking protein release, flow rate, and the protein release constant, determined from batch experiments, is derived. Good agreement between the theoretical prediction of protein release and experimental results with the flow system was obtained.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Biochemical and Microbiological Technology and Engineering 2 (1960), S. 49-70 
    ISSN: 0368-1467
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new vibrator, commercially available as the Sonomec Wave-Pulse Generator, is described, in which micro-organisms may be disrupted by shaking with glass beads. The amplitude and frequency of vibration of the shaker may be varied independently by suitable linkages incorporated in the mechanism. A study has been made of the effect of several variables, particularly the height of the liquid column in the vibrating container, on the rate of disruption. A relation is shown to exist between the acoustic heating produced in the container by the passage of sound waves through the liquid and the rate of disruption of baker's yeast. It is considered that at most depths of the liquid column, the action is similar to that of other shakers, but at a certain depth of liquid, additional forces arise which greatly increase the rapidity of disruption. How these forces act is not known. Factors affecting the rate of disruption of baker's yeast, Corynebacterium xerosis and Bacillus megatherium have been studied and a comparison has been made of the fractions obtained by differential centrifugation of the cell dispersion and compared with similar preparations from the Hughes press.
    Additional Material: 6 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Biochemical and Microbiological Technology and Engineering 3 (1961), S. 405-433 
    ISSN: 0368-1467
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two commercially available ultrasonic instruments are described, in which micro-organisms and other cells may be disintegrated.Sound waves (20 kc/s) are generated in the cell suspension by means of titanium velocity transformers (probes) coupled to a magnetostriction transducer. One instrument operating at 500 W will disintegrate from 2 to 500 ml, the other operating at 50 W from 1 ml to 30 ml.Yeast was used as a test organism but results on some other organisms are also given. Cell rupture is shown to be independent of sonically generated free radicals, but enzyme inactivation (alcohol dehydrogenase) is accelerated by free radicals. Increasing the viscosity, decreasing surface tension of the suspending medium, or the presence of CO2 decreases disintegration. The addition of solid nuclei such as powdered glass, as well as small air bubbles, increases disintegration.This is consistent with disintegration being due to cavitation, but does not indicate the precise mechanism of cell rupture. Some effects of sonic disruption are compared with disruption by other methods.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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