Summary:A competitive and a sandwich enzyme linked immunosorbent assay (ELISA) were developed for human leukocyte collagenase and gelatinase.The competitive assay could detect 0.5 ng collagenase and 0.05 ng gelatinase. The detection limit of the sandwich ELISA was 0.05 ng for collagenase and 0.02 ng for gelatinase.No cross reactivity between human leukocyte collagenase and gelatinase was detected. The sandwich ELISA was used to determine plasma levels of these enzymes. The 90% ränge for collagenase was between 0 and 50 g/l; the 90% ränge for gelatinase was between 27 and 94 g/l.
The theory of solute extraction in viscous single-drop systems is extended to show (1) the dependence of the asymptotic Nusselt number on the Peclet number from N p , = 0, the molecular diffusion limit, to N p , = 00, the Kronig and Brink limit, and (2) the dependence of the diffusion entry region Nusselt number on the Peclet number and the initial concentration profile.A numerical solution of the diffusion equation, limited to dilute solute concentrations and salute transport by viscous convection and molecular diffusion, is presented from which the nature of the Nusselt number is deduced. The observed oscillatory behavior of the Nusselt number in the diffusion entry region, as N p , +cs, is given a simple physical interpretation in terms of the circulation period of the drop liquid.The model is based upon the Hadamard stream function which theoretically is limited to creeping flow; however some experimental evidence indicates that flow fields similar to the Had0ma.d stream function exist at continuous phase Reynolds numbers of the order of ten. It is customary to analyze and correlate the results of single-drop extraction experiments in terms of mathematical models. For example, experiments with viscous drops normally are related to either the stagnant-drop model, at the extreme of vanishing circulation or to the Kronig and Brink (10) model at the opposite extreme; whereas ex-L. J ! $ Johns, Jr., is with Dow ChFmical Company, Midland, Michigan. &ann is with the University of Maryland, College Park, Mary-R. B. land. periments with turbulent drops frequently are related to the Handlos and Baron model ( 1 5 ) .This paper presents the solution to a viscous %ow model which reduces to the stagnant-drop and the Kronig and Brink models in the respective limits, that is, N p s = 0 and Np. + co, and complements these models on the interval 0 < N p e < co. A mathematical formulation of the model will be given after a brief summary of the problem and a presentation of the major assumptions.
A study has been made of the effect of column geometty and flow condition upon the dispersed-phase holdup in an rotating disk type of extraction column. Variables investigated were stator opening, disk diameter, compartment height, rotor speed, and flow rates of the dispersed and continuous phases. The toluene-water system, with the toluene dispersed, was used throughout the study. The radio-isotope technique was used to measure the dispersed-phase holdup.Results of this study as well as those of earlier investigators have been used to expand upon the design equations proposed by Logsdail, Thornton, and Pratt for estimating flooding rates and dispersed-phase holdup in rotating disk columns. Modifications to increase the accuracy of prediction of these equations have also been suggested, while possible limitations in their application have been indicated.The rotating disk column was patented by G . H. Reman ( I ) , who claimed that the column has a high volumetric efficiency, is of straightforward construction, is cheaper to build for equivalent capacities than other existing apparatus of comparable efficiency, and can be scaled up to comparatively large diameters without undue loss in efficiency. The column consists of a number of compartments formed by a series of stator rings, with a rotating disk centered in each compartment and supported by a rotating shaft. The lighter liquid enters the column at the bottom and flows upward countercurrently to the descending heavier liquid. One of the liquids is dispersed by the rotating disks and flows through the column in a toroidal pattern.Reman and Olney (Z), Reman and van de Vusse ( 3 , 4 ) , and Vermijs and Kramers ( 5 ) have published considerable operational and mass transfer data on specific small and large rotating disk extraction columns. Logsdail, Thornton, and Pratt (6) studied flooding rates for a 3-in. diameter rotating disk column in terms of column variables and physical properties. In a few cases the dispersed-phase holdup below and/or at the flood point was determined. Mass transfer data were also obtained. The column variables studied included stator opening at 2.0 and 2.25 in. disk diameter at 1.0, 1.5, and 2.0 in., compartment height at 0.50, 1.0, 2.0, and 4.0in. and rotor speed over the range of 500 to 1,800 rev./min. Water was used throughout as the continuous phase, while toluene, butyl acetate, iso-octane, white spirit, and benzene were used as the dispersed phases.The authors observed during operations of their rotating disk column that the size of the dispersed-phase droplet was independent of the phase flow rates and the dispersed-phase holdup. Using semitheoretical considerations they postulated that for such cases the phase flow rates and holdup for a specific system at a given column geometry and rotor speed can be related by the equation VdV,where TN is regarded as the mean vertical component of velocity of the droplets with respect to the continuous phase.The authors further asserted that at flooding point the flow rates reached a maximum, ...
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