Aspects of the Strategy

Merrifield s original idea was based on the general scheme of stepwise condensation of N-protected amino acids to the first one, which is linked with its carboxyl function by an ester bond to the insoluble polymer support. This way of solid phase peptide synthesis resulted from the well-known risk of racemization during activation of peptidic carboxyl components, which is minimized in activated amino acid derivatives, N-acylated by urethane-type protecting groups [40] (Fig. 7). Depending on the chosen method, the C-terminal activation of N-protected peptides tends to racemize a certain amount of the material because of the possible formation of an oxazolinone intermediate [41] (Fig. 8). 

For that reason, the applicability of the other strategy introduced by R. L. Letsinger and M. J. Kornet in 1963 [42] is in contrast to the Merrifield procedure limited. In the second method the stepwise peptide synthesis starts from the opposite direction, beginning from the N-terminal amino acid bound by its amino function to an insoluble support. The peptide is elongated by activations of the solid phase carboxyl component on each 

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Certain aspects of the strategy used to sequence DNA resemble the methods used to sequence proteins. Both types of molecules require methods amenable to lengthy polymers, but in the case of DNA, a single DNA molecule is so long that it is absolutely... 

As we will see from the examples on the following pages, a wide range of approaches have been developed to access lanthanide arrays. We will deal with them by using examples of a number of different classes of systems in the solid state and in solution to illustrate key aspects of the strategies used to prepare these complexes. 

A questionnaire given to Coordinators asked them to rate aspects of the strategy in terms of its usefulness (the rating scale was 4 - Of critical importance 3 - Very useful 2 - Somewhat useful 1 - Not very useful). All aspects were valued, but especially valued were the SIS Components (mean 3.4) and Component Mapping (3.1), staff meetings (3.4), and the action planning process (3.6). Infrastructure... 

Further details of the BB, sometimes referred to as Ladyzhenskaya-Babuska-Brezi (LBB) condition and its importance in the numerical solution of incompressible flow equations can be found in textbooks dealing with the theoretical aspects of the finite element method (e.g. see Reddy, 1986), In practice, the instability (or checker-boarding) of pressure in the U-V-P method can be avoided using a variety of strategies. 

The retrosynthetic analysis described above outlines a triply convergent strategy towards the synthesis of zaragozic acid A (1). The most pleasing aspect of the retrosynthetic strategy is the rapid and enantioselective manner in which the two-dimensional molecule... 

In this short initial communication we wish to describe a general purpose continuous-flow stirred-tank reactor (CSTR) system which incorporates a digital computer for supervisory control purposes and which has been constructed for use with radical and other polymerization processes. The performance of the system has been tested by attempting to control the MWD of the product from free-radically initiated solution polymerizations of methyl methacrylate (MMA) using oscillatory feed-forward control strategies for the reagent feeds. This reaction has been selected for study because of the ease of experimentation which it affords and because the theoretical aspects of the control of MWD in radical polymerizations has attracted much attention in the scientific literature. 

The second approach is addressed to elaborate methods able to derive from accurate calculations the points of interest for the interpretation The strategy, in general, consists in the adoption of a simpler model (the mathematical aspects of the model are again concerned) and the task consists in reducing the information coming from the full in-depth calculation (not the the numerical values of observables and other statutory quantities alone) to the level of the simpler model. For example accurate calculations may be reduced at the level of a simple VB theory (Robb, Hiberty) or of a simple MO perturbation scheme (Bernardi) making more transparent the interpretation. 

In order to systematically remedy the previous drawbacks, we recently proposed to perform a perturbation treatment, not on a wavefunction built iteratively, but on a wavefunction that already contains every components needed to properly account for the the chemistry of the problem under investigation [34], In that point of view, we mean that this zeroth-order wavefunction has to be at least qualitatively correct the quantitative aspects of the problem are expected to be recovered at the perturbation level that will include the remaining correlation effects that were not taken into account in the variational process any unbalanced error compensations or non-compensations between the correlation recovered for different states is thus avoided contrary to what might happen when using any truncated CIs. In this contribution, we will report the strategy developed along these lines for the determination of accurate electronic spectra and illustrate this process on the formaldehyde molecule H2CO taken as a benchmark. 

With this in mind, the search for molecular markers that define populations of neurons in areas important for arousal is clearly warranted. In this chapter we describe the identification of four peptidergic systems that modulate different aspects of the sleep-wakefulness cycle. The success of this strategy demonstrates the need for new markers of neuronal cell types, which may define populations of neurons critical for our understanding of cortical activity and sleep. 

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