Restricted mobility

For acute stroke patients with restricted mobility, they recommend prophylactic low-dose subcutaneous heparin or low-molecular-weight heparins or heparinoids (grade lA). 

Particular advantages of solvent-free methods are enhancement of reactivity, because of the increased concentration, and specific selectivity, because of the restricted mobility. 

Equation (10) is exact in the absence of local motion. It provides a good approximation for the protein core residues, characterized by restricted mobility in the protein backbone in this case both J(0) and /(local motion to p in Eq. (10) is canceled out The approach described here is rather general and accommodates both large 1) and small < 1) molecules and mole-... 

Recently, the PER of phenyl acetate and phenyl benzoate has been studied within zeolites of the faujasite and pentasil families, which are structurally very different. [277,278] It was found that for phenyl acetatet in faujasites X and Y, the predominating product is the ortho isomer, whereas in the pentasils ZSM-5 and ZSM-11, the preferred product is the para isomer. These differences have been explained taking into account the different sizes and shapes of the cavities and channels of the two families. The faujasites are made up of channels of 8 A diameter, leading to supercages of 13 A diameter, where the reaction is expected to occur, whereas the pentasils are made up of narrow channels of 6 A diameter. In the X and Y faujasites, the ortho position would be favored due to the restricted mobility, whereas in the channels of ZSM-5 and ZSM-11, there would be a shape limitation because the ortho isomer does not fit but the para isomer does (Table 15). With phenyl benzoate inside X or Y zeolites, the same... 

Note 1 The mobility of the polymer segments surrounding the multiplets is reduced relative to that of bulk material. With increasing ion content, the number density of the ionomer multiplets increases, leading to overlapping of the restricted mobility regions around the multiplets and the formation of clusters. 

In patients with severely restricted mobility during acute illness —... 

Medical patients during acute illness In medical patients with severely restricted mobility during acute illness, the recommended dose is 5,000 units administered by subcutaneous injection once daily. In clinical trials, the usual duration of administration was 12 to 14 days. 

When high-resolution NMR spectra have to be recorded of a polymeric sample, one has to recognize that polymer solutions are in general highly viscous. To prevent excessive signal broadening caused by this restricted mobility of the solution, polymer solutions for NMR studies have to be highly diluted (approx. 

Cyclization reactions in systems with restricted mobility (most notably ring systems) to form either fused or bridged ring systems, in order to determine the relative disposition of substituents, has played an important role in the structural elucidation of many natural products 109. The method is based on the precondition that only one relative configuration will allow ring closure for steric reasons. Two recent examples may serve to illustrate the procedure. 

The anionic catalysts listed earlier react with lactam monomer to first form the salt, which in turn will dissociate to the active species, namely, the lactam anion. A strongly dissociating catalyst in low concentrations, therefore, is always preferable to weakly dissociating catalysts in higher concentrations. The catalytic activity of the various alkali metal and quaternary salts of a lactam generally follows the extent of their ionic dissociation that is controlled by the cation. Activity of a salt decreases with increasing size of the cation due to restricted mobility and decreased ionization potential. 

This obvious drawback can be circumvented by adding polymer bound antioxidants. Actually, polymer bound antioxidants are highly resistant to volatilization and leaching. However, the main disadvantage polymer bound antioxidants is their restricted mobility. On the other hand, if the antioxidant is bound to a low molecular weight polymer this problem is not as serious. 

Since AG° = AH0- TAS° (see Chapter 6), it follows that the negative value of AG° for hydrophobic interactions must result from a positive entropy change, which may arise from the restricted mobility of water molecules that surround dissolved hydrophobic groups. When two hydrophobic groups come together to form a "hydrophobic bond," water molecules are freed from the structured region around the hydrophobic surfaces and the entropy increases. The AS° for Eq. 2-9 is about 12 J deg 1 mol-1. Attempts have been made to relate this value directly to the increased number of orientations possible for a water molecule when it is freed from the structured region.64 However, interpretation of the hydrophobic effect is complex and controversial.65-713... 

Whether polymerized model membrane systems are too rigid for showing a phase transition strongly depends on the type of polymerizable lipid used for the preparation of the membrane. Especially in the case of diacetylenic lipids a loss of phase transi tion can be expected due to the formation of the rigid fully conjugated polymer backbone 20) (Scheme 1). This assumption is confirmed by DSC measurements with the diacetylenic sulfolipid (22). Figure 25 illustrates the phase transition behavior of (22) as a function of the polymerization time. The pure monomeric liposomes show a transition temperature of 53 °C, where they turn from the gel state into the liquid-crystalline state 24). During polymerization a decrease in phase transition enthalpy indicates a restricted mobility of the polymerized hydrocarbon core. Moreover, the phase transition eventually disappears after complete polymerization of the monomer 24). 

For mesostructured aluminophosphates with lamellar structure WISE spectra indicate that template surfactant species have very restricted mobility as the ll wide lines are very broad.3 This is also consistent with the trans-conformation of the aliphatic chains. Other representatives of mesoporous A1PO exhibited template species with much narrower H resonances.2... 

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