Special Strategies

Aniline and its derivatives are so reactive in elec trophilic aromatic substitu tion that special strategies are usually necessary to carry out these reactions effec tively This topic is discussed in Section 22 14... 

Moreover, some special strategies have been developed from this type of combination to achieve efficient therapeutic effects. For example, upward-moving and downward-moving herbs, and dispersing and restraining herbs may be used at the same time. 

Moreover, some special strategies have been developed from this type of combination to attain efficient therapeutic effects. For example, upward-moving and downward-moving herbs, and dispersing and restraining herbs, may be used at the same time. The first herb treats the disorder and the second herb - which has different or opposite properties, directional tendency and functions - serves as its assistant. In this way, it keeps the action of the first herb steady and moderate. 

For handling acetylene in chemical processes under pressure a special strategy has been developed to solve the specific problems of this chemical - the decomposition of the substance even under mild conditions. It is known that this reaction is generating a pressure increase of approximately factor 11 above the normal working pressure. Therefore the design pressure of all components of acetylene plants should be selected eleven times higher compared to the operating pressure. 

Another alternative technique, solid-phase microextraction (SPME), was used for the determination of fluoxetine [79] and several TCAs [80], SPME is a miniaturized and solvent-free technique, where analytes are extracted from the sample by adsorption on a thin polymer coating fixed to the solid surface of a fiber, located inside an injection needle or a capillary. Its main disadvantage is that special strategies are needed to couple SPME to the LC-MS analysis. 

The calculation demonstrates that the concept of a strain-free bond has a clear electronic basis. It is important to note that in molecular mechanics the concepts of force constant and strain-free parameter are intimately linked. The calculated C-C pair, ke, do = (4.88 Ncm-1,1.51 A), are very close to the best empirically optimized values of the most extended force fields. Although special strategies will be required to calculate specific ke, do pairs, the problem may be considered solved in general and the empirical estimates used with confidence. As a rule of thumb it is noted that, to first approximation,... 

Purification of chemokines from natural sources requires special strategies. First of all, the detection system should be useful to detect the required chemokine at low concentrations, i.e., it is important to choose an assay system that allows the detection of low amounts of the chemokine in a screening system. Screening systems often used are Boyden chamber chemotaxis assay... 

Carbonic anhydrases accelerate CO2 hydration dramatically. The most active enzymes, typified by human carbonic anhydrase II, hydrate CO2 at rates as high as k =10 s, or a million times a second. Fundamental physical processes such as diffusion and proton transfer ordinarily limit the rate of hydration, and so special strategies are required to attain such prodigious rates. 

A radical species may also be generated by reduction of an electron-deficient compound and a classical entry to 4,4 -bipyridines is the reduction of a pyridine by sodium and subsequent rearomatization. Figure 8a illustrates the use of such a reduction in order to prepare the precursor of a sodium-ion molecular switch [30], A more general route, derived from the ancient copper-catalyzed Ullmann coupling, is the metal-induced dimerization of an aryl halide. The key step is a reductive elimination within the coordination sphere of the metal. A nickel(O) complex, in stoichiometric quantities, is usually selected for this purpose. Constable and Ward have used such a reaction to prepare a bis-terpyridine from an interesting synthon, which would have otherwise required a more specialized strategy with dedicated intermediates (Figure 8b) [31]. 

In this context, SEE has a great potential for replacing older extraction methods, e.g., Soxhlet extraction. Despite important limitations described elsewhere, with the help of special strategies for the extraction of moderately polar and highly polar analytes, the SEE range of applications will dramatically increase in the near future. 

Special Strategies Used for Metabolite Detection/Characterization.168... 

SPECIAL STRATEGIES USED FOR METABOLITE DETECTION/CHARACTERIZATION... 

Using special strategies such as those involving, e.g., a coaxial jet mixer [79], a packed bed connector [80] or a metal helix insertion [66]. 

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