Two-stage procedure

In dissimilarity-based compound selection the required subset of molecules is identified directly, using an appropriate measure of dissimilarity (often taken to be the complement of the similarity). This contrasts with the two-stage procedure in cluster analysis, where it is first necessary to group together the molecules and then decide which to select. Most methods for dissimilarity-based selection fall into one of two categories maximum dissimilarity algorithms and sphere exclusion algorithms [Snarey et al. 1997]. 

In the Strecker synthesis an aldehyde is converted to an a ammo acid with one more carbon atom by a two stage procedure m which an a ammo nitrile is an mterme diate The a ammo nitrile is formed by reaction of the aldehyde with ammonia or an ammonium salt and a source of cyanide ion Hydrolysis of the nitrile group to a car boxylic acid function completes the synthesis... 

There is a two-stage procedure to help judge the veracity of a program s output ... 

Figure 3. Nomograph to determine the optimum number of replications in the second stage of a two-stage procedure.

Monomer concentrations Ma a=, ...,m) in a reaction system have no time to alter during the period of formation of every macromolecule so that the propagation of any copolymer chain occurs under fixed external conditions. This permits one to calculate the statistical characteristics of the products of copolymerization under specified values Ma and then to average all these instantaneous characteristics with allowance for the drift of monomer concentrations during the synthesis. Such a two-stage procedure of calculation, where first statistical problems are solved before dealing with dynamic ones, is exclusively predetermined by the very specificity of free-radical copolymerization and does not depend on the kinetic model chosen. The latter gives the explicit dependencies of the instantaneous statistical characteristics on monomers concentrations and the rate constants of the elementary reactions. 

The immobilization procedure performed in two stages allows one to exclude the detrimental effect of acid on the entrapped proteins [44,71,86]. It was demonstrated [87] by the example of a set of oxidases that their activity was retained if the entrapment was carried out at a pH as close to their isoelectric point (pi) as possible. Because the pi value of most enzymes is in the neutral region, the two-stage procedure favors the retention of their functionality. Therefore, the pH shift to the optimal region provides a means of extending the sol-gel entrapment to a wide range of enzymes [45,71]. 

The two-stage procedure eliminates the detrimental effect of acid, but an alcohol, which is produced in the course of precursor hydrolysis Equation (2), remains in solution. This can cause unfolding of the biomacromolecule and denaturation of... 

Ow et al. (2005) developed an improved method of incorporating fluorescent molecules into silica particles using a modified Stober synthesis, which resulted in both enhanced fluorescence and photostability of the encapsulated dyes. In this two-stage procedure, reactive organic dyes... 

It can be shown (Mikhail, 1976), reproduced here in Appendix A, that the solution for the overall set of balance equations can be obtained from the equivalent two-stage procedure as follows ... 

Equivalence between the Solution of the Overall Set of Balance Equations and the Two-Stage Procedure... 

If H0 is rejected, a two-stage procedure is initiated. First, a list of candidate biases and leaks is constructed by means of the recursive search scheme outlined by Romagnoli (1983). All possible combinations of gross errors (measurement biases and/or process leaks) from this subset are analyzed in the second stage. Gross error magnitudes are estimated simultaneously for each combination and chi-square test statistic calculations are performed to identify the suspicious combinations. We will now explain the stages of the procedure. 

Table 8.1(c) shows Marx s procedure for calculating prices of production. This is a two-stage procedure. First, the average rate of profit is established for the economy as a whole, so that... 

A convenient procedure for assessing the digestibility of forages is the cellulase digestibility technique. This was refined by Jones and Hayward (1973) at the Welsh Plant Breeding Station (WPBS) in Aberystwyth (since 1992, the Institute for Grassland and Environmental Research). It was later extended to a two-stage procedure with a pepsin pre-treatment (Jones and Hayward, 1975). 

The overall methodology of IB polymerization by the two-stage procedure has been followed (see Sect. 2.2.1). The terminal allyl-functionahzation of the hving PIB arms was carried out by adapting a procedure developed in these laboratories [63]. Allyltrimethylsilane (ATMS) ( 100-fold excess relative to the PIB chain end) was added when IB conversion has reached 95%. After 60 min the polymerization mixture was poured into an excess of chilled methanol, the product separated, redissolved in hexanes, washed with water and methanol, and finally reprecipitated into methanol. 

The strategy involved initiation of St polymerization by the living PIB arms of octa-arm stars. Scheme 7 illustrates the key steps and structures. The overall methodology of living IB polymerization by the two-stage procedure has been followed (see Sect. 4.1). Briefly, stars with predetermined arm molecular weights were prepared by the use of 1, in conjunction with BClj-TiC coinitiators used in two stages, then St was added to obtain the star blocks. 

A number of different approaches have been suggested for systematic reduction of detailed reaction mechanisms [160,313], The most common approach involves a two-stage procedure. First, a skeletal mechanism is established by removing all redundant species and reactions. Second, the skeletal mechanism is further reduced by order-of-magnitude approximations, resulting in the analytically reduced mechanism. 

The method described here is adapted from the procedure of Staudinger and Freudenberger.2 It has been found to be more convenient and to give more reproducible results than the two-stage procedure given in Organic Syntheses 3 where references to other methods of preparation are also cited. 

Fig. 3 Basis of the Soai amplifying autocatalysis illustrated by a two-stage procedure...

The idea of the sequential QM/MM method is thus to join the quantum calculations and the computer simulations in an efficient way to reduce the number of QM calculations and hence the computational cost. Therefore, in the two-stage procedure the system is first simulated using classical force fields for all interactions,... 

We now discuss what it means for a method of analysis to be robust or adaptive . Lenth s method is adaptive because of the two-stage procedure used to obtain the pseudo standard error. The pseudo standard error i is computed from... 

In the last of the six papers Hong and Huang have examined how added surfactants such as FC-143, ammonium perfluorooctanoate [CF3(CF2)6 CO2NH4], influenced the Ti02-photocatalyzed decomposition of a large number of PCB congeners adsorbed on soils [102]. The authors concluded that the perfluorinated surfactants are photostable and do not get directly involved in the photochemistry of the chlorobiphenyls (unlike the surfactants mentioned earlier), and the surfactants extract the PCBs from the soil which are then expeditiously photoxidized on TiC>2. This represents a novel two-stage procedure to remove PCBs from soil and then destroy them. 

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