Displacement technique

As ATP binding to myosin, and ATP hydrolysis, are both faster than the overall observed ATPase rate, the slow step that follows the rapid phosphate burst and that must limit the overall observed ATPase rate must be the release of phosphate, or the release of ADP. The rate at which ADP is released was measured by a displacement technique (Trentham et al., 1972), in which the rate at which ADP bound to S-1 is displaced by ATP was measured. This experiment showed that the rate of ADP release (2 s ) is greater than the overall rate of hydrolysis (0.03 s" ). Thus the release of Pj, and not that of ADP, is rate limiting. 

Nguyen et al. [205] designed a volume displacement technique that was used to measure the capillary pressures for both hydrophobic and hydrophilic materials. One requirement for this method is that the sample material must have enough pore volume to be able to measure the respective displaced volume. Basically, while the sample is filled wifh water and then drained, the volume of water displaced is recorded. In order for the water to be drained from fhe material, it is vital to keep the liquid pressure higher than the gas pressure (i.e., pressure difference is key). Once the sample is saturated, the liquid pressure can be reduced slightly in order for the water to drain. From these tests, plots of capillary pressure versus water saturation corresponding to both imbibitions and drainages can be determined. A similar method was presented by Koido, Furusawa, and Moriyama [206], except they studied only the liquid water imbibition with different diffusion layers. 

Brusseau, M.L., Jessup, R.E., and Rao, P.S.C. Sorption kinetics of organic chemicals evaluation of gas-purge and miscible-displacement techniques, Environ. Sci. Technol, 24(5) 727-735, 1990. 

Rates for this reaction may easily be measured by disappearance of azide UV absorption. Most importantly, kinetic saturation behavior is noted with sufficient amounts of the reactants cycloaddition velocity becomes independent of substrate concentration. As is familiar from enzyme catalysis, this indicates complete occupancy of all available cucurbituril by reacting species. In actuality, the rate of the catalyzed reaction under conditions of saturation was found to be the same as that for release of the product from cucurbituril. Such a stoichiometric triazole complex was independently prepared and its kinetics of dissociation were examined by the displacement technique previously outlined, giving the identical rate constant of 1.7xl0 s under the standard conditions. (It is not uncommon for product release to be rate-limiting in enzymic reactions). 

The heat output is determined by a Parr adiabatic bomb calorimeter in an argon atmosphere (5 atm.). The gas volume of a sample is determined in the same set-up except that the sample is burnt at 1 atmosphere of air in place of argon atmosphere (inert atmosphere) and the volume of gases liberated is measured by a water displacement technique. 

Carski, T.H., and D.L. Sparks. 1985. A modified miscible displacement technique for investigating adsorption-desorption kinetics in soils. Soil Sci. Soc. Am. /. 49 1114-1116. 

Sparks, D. L., and Recheigl, J. E. (1982). Comparison of batch and miscible displacement techniques to describe potassium adsorption kinetics in Delaware soils. Soil Sci. Soc. Am. J. 46, 875-877. 

The introduction of the samples onto the capillary column can be carried out by either displacement techniques or electrokinetic migration. Three methods of displacement or hydrostatic injection are available a) direct injection, or pressure b) gravity flow, or siphoning and c) suction. The electrokinetic injection method arose from findings that electroosmosis act like a pump (80). Both methods have advantages and disadvantages. For example, a bias has been reported in electrokinetically injected... 

Laboratory-based methods of pore water displacement are designed to approximate diffuse water in quasi-equilibrium with the soil solid phase. Methodologies for obtaining unaltered soil pore water in a laboratory setting may be broadly defined as displacement techniques and comprise... 

Deshmukh, R., Leitch, W. E., and Cole, D. L. (1998). Application of sample displacement techniques to the purification of synthetic oligonucleotides and nucleic acids A mini-review with experimental results. J. Chromatogr. 806, 77-92. 

Displacement technique [44] Initially, the polymer was equilibrated in MeCN and the template and a variety of compounds, including potential reporters (Fig. 20.17), were chromatographed. All of the reporter compounds examined displayed a low affinity for the MIP, giving k values of at most 1.0, while that of )8-estradiol was 3.5 (kimp / -estradiol dansylate = 0.73). 

The detailed chemistry of the stratum corneum is complicated by the membrane s composition, formation, and structure. Some gross chemical characterizations have determined the primary chemical components of the tissue which are shown in Table I (29). The tissue is primarily cellular with approximately 10% extracellular components which are lipid and mucopolysaccharides. The bulk of the tissue is densely packed intracellular fibrous protein associated with lipids, resulting in a dry general body corneum density of 1.35-1.40 gm/cm as determined by a gas displacement technique (30). 

After equilibration, the films were first rinsed quickly by a dilution and displacement technique which insures that the films are not exposed to the protein solution/air interface. The dilution-displacement rinse was done by running solvent through the equilibration bottle at about 400 ml/min for approximately I min using a two-hole rubber stopper fitted with two glass tubes, one for entrance and one for exit of buffer. 

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