Substitution effect INDEX

The hydrophobicity index is also suitable for correlating the cM values of various substituted sodium alkane 1-sulfonates [68]. The perfluoroalkyl substituent, e.g., 8 17 has a pronounced hydrophobic effect (/ = 1.66 at 75°C, sodium salt), whereas the hydrophilic disulfonates have values distinctly below 1 (for a-disulfonates, / = 0.75 was derived [70]). Further, it was somewhat surprisingly shown that substituents like 1-hydroxymethyl, 3-hydroxyethoxy, or even the hydroxyethoxyethoxy groups have hydrophobic effects. 

The susceptibility or mixing coefficients, pj and pj , depend upon the position of the substituent (indicated by the index, /) with respect to the reaction (or detector) center, the nature of the measurement at this center, and the conditions of solvent and temperature. It has been held that the p/scale of polar effects has wide general applicability (4), holding for substituents bonded to an sp or sp carbon atom (5) and, perhaps, to other elements (6). The or scale, however, has been thought to be more narrowly defined (7), holding with precision only for systems of analogous pi electronic frameworks (i.e., having a dependence on reaction type and conditions, as well as on position of substitution). 

Three main parameters were used to evaluate the efficiency of the polymerization, namely monomer conversion (Cmma), initiation efficiency of the reaction (/ = Mn theo/3 n,SEc), and polydispcrsity index (PDI). These results are depicted in Fig. 2. It is obvious that the Cu(I)-catalyzed systems are more effective than the Fe(II)-catalyzed systems under the studied conditions. It was concluded that a bipyridine based ligand with a critical length of the substituted alkyl group (e.g., dHbpy) shows the best performance in Cu(I)-mediated systems. Besides, Cu(I) halide-mediated ATRP with 4,5 -Mbpy as the ligand and TsCl as the initiator was better controlled than that with dMbpy as the ligand, and polymers with much lower PDI values were obtained in the former case. 

Therapy is perfectly adequate with simple iron salts (Table 2). In adults ferrous gluconate, fumarate or sulphate are all of proven equal efficiency. Approximately 50 mg of iron is present in each tablet with the remaining 300 mg made up with an inert filler. These are given on an empty stomach at least twice a day but should nausea prevail they can be taken with food. Absorption of slow release preparations is not recommended since iron is detached from the carrier beyond the main areas of absorption in the duodenum or jejunum. Stools turn black in all cases and this is a useful index of patient compliance. In 25% of individuals gastrointestinal tract side effects are encountered in the form of diarrhoea or constipation and patients will often spontaneously discontinue medication. It is therefore essential that a tablet-count be carried out on a regular basis with a substitute being provided when this first-line medication is intolerable. In children the same preparations are favoured as syrups these are given twice... 

Therefore, within limits, we may interpret N in (3.41) as the effective refractive index of the slab of particles. This leads naturally to the question To what extent is N similar to the refractive index of a homogeneous medium For example, under what conditions, if any, will substitution of N into the expression for the reflection coefficient of a homogeneous slab yield physically correct results We can answer the latter and more specific of these two questions by calculating the field Er at the point P (Fig. 3.8), which is the sum... 

Recent research by Kornilov et al. (91ZOR144) on the aromaticity of 6-nitro-TPs substituted at C-2 revealed that the experimentally detected values (by reversible covalent hydration) proved more sensitive to substituent effects than the modified aromaticity index ANs of Pozharskii did. 

Therapeutic index (ABBR TI) A ratio used to represent the relative safety of a particular drug the larger the therapeutic index, the safer the drug. It is calculated as the median toxic dose divided by the median effective dose. (In animal trials, the median lethal dose is often substituted for the median toxic dose.)... 

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