Fluidity nuclear

Alkylated aromatics have excellent low temperature fluidity and low pour points. The viscosity indexes are lower than most mineral oils. These materials are less volatile than comparably viscous mineral oils, and more stable to high temperatures, hydrolysis, and nuclear radiation. Oxidation stabihty depends strongly on the stmcture of the alkyl groups (10). However it is difficult to incorporate inhibitors and the lubrication properties of specific stmctures maybe poor. The alkylated aromatics also are compatible with mineral oils and systems designed for mineral oils (see Benzene Toulene Xylenes and ethylbenzene). ... 

The most common sterol in membranes is cholesterol (Chapter 14), which resides mainly in the plasma membranes of mammalian cells but can also be found in lesser quantities in mitochondria, Golgi complexes, and nuclear membranes. Cholesterol intercalates among the phospholipids of the membrane, with its hydroxyl group at the aqueous interface and the remainder of the molecule within the leaflet. Its effect on the fluidity of membranes is discussed subsequently. 

This report presents a determination of the fluidity of water adsorbed to saturation in zeolite 13-X. As a measure of the fluidity, the time between molecular jumps or correlation time, r, is employed it has been derived from measurements of nuclear magnetic resonance (NMR) relaxation times via the theory of Bloembergen, Purcell, and Pound (BPP)... 

In Fig. 4, we plot the volume dependences of the diffusivities of various model systems, all calculated for argonlike particles, and for the laboratory system methyl cyclohexane, which seems to be representative. Data for the latter are available for two temperatures from the accurate nuclear magnetic resonance (NMR) spin-echo measurements of Jonas et al. To group the data for different systems for better comparison of their behavior, we have obtained a reducing parameter for each liquid by taking advantage of the observations of Batchinski and Hildebrand that fluidities , and diffusivities D of highly fluid molecular liquids vary linearly with volume. 

The dynamic properties of the membrane discussed in the previous two sections have their origin in rotation about the bonds in the lipid hydrocarbon chains. It is this rotational isomerism which is the fastest molecular motion and is the fundamental basis or the membrane fluidity. The chain motions are best studied by H NMR of lipids whose chains have been specifically deuterated. The nuclear quadrupole splittings can be used to measure the order... 

---