A COMPARISON OF OPTICAL AND MANOMETRIC METHODS FOR THE ASSAY OF HUMAN SERUM CHOLINESTERASE

1955 ◽  
Vol 33 (4) ◽  
pp. 568-574 ◽  
Author(s):  
W. Kalow ◽  
H. A. Lindsay
Keyword(s):  
Human Serum ◽  
Temperature Control ◽  
Reaction Rate ◽  
Good Accuracy ◽  
Spectrophotometric Assay ◽  
Serum Cholinesterase ◽  
Ultraviolet Spectrophotometry ◽  
Influence Of Temperature ◽  
Hydrolysis Rates ◽  
Influence Of Temperature On

A method for the assay of human serum cholinesterase (pseudocholinesterase) is described in detail. The disappearance of benzoylcholine is measured by ultraviolet spectrophotometry. Minute amounts of serum and of the substrate are sufficient for a rapid and convenient test of good accuracy. The influence of temperature on the reaction rate is given particular attention, since temperature control is not as easily achieved in the spectrophotometer as for instance in a Warburg apparatus. Although the results of the spectrophotometric assay are fundamentally the same as those obtained by using a conventional gasometric method with acetylcholine as a substrate, small but significant differences between the two answers occur. These differences depend on the substrates and not on the methods as such. The ratio of hydrolysis rates of the two substrates, benzoylcholine and acetylcholine, varies slightly from person to person. If benzoylcholine is used in the Warburg apparatus, a concentration above the optimum must be employed in order to develop sufficient gas for measurement.

A COMPARISON OF OPTICAL AND MANOMETRIC METHODS FOR THE ASSAY OF HUMAN SERUM CHOLINESTERASE

1955 ◽  
Vol 33 (1) ◽  
pp. 568-574 ◽  
Author(s):  
W. Kalow ◽  
H. A. Lindsay
Keyword(s):  
Human Serum ◽  
Temperature Control ◽  
Reaction Rate ◽  
Good Accuracy ◽  
Spectrophotometric Assay ◽  
Serum Cholinesterase ◽  
Ultraviolet Spectrophotometry ◽  
Influence Of Temperature ◽  
Hydrolysis Rates ◽  
Influence Of Temperature On

A method for the assay of human serum cholinesterase (pseudocholinesterase) is described in detail. The disappearance of benzoylcholine is measured by ultraviolet spectrophotometry. Minute amounts of serum and of the substrate are sufficient for a rapid and convenient test of good accuracy. The influence of temperature on the reaction rate is given particular attention, since temperature control is not as easily achieved in the spectrophotometer as for instance in a Warburg apparatus. Although the results of the spectrophotometric assay are fundamentally the same as those obtained by using a conventional gasometric method with acetylcholine as a substrate, small but significant differences between the two answers occur. These differences depend on the substrates and not on the methods as such. The ratio of hydrolysis rates of the two substrates, benzoylcholine and acetylcholine, varies slightly from person to person. If benzoylcholine is used in the Warburg apparatus, a concentration above the optimum must be employed in order to develop sufficient gas for measurement.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

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