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The bilayer can adopt a solid gel phase state at lower temperatures but undergo phase transition to a fluid state at higher temperatures, and the chemical properties of the lipids' tails influence at which temperature this happens. The packing of lipids within the bilayer also affects its mechanical properties, including its resistance to ...
Cholesterol is the principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils. [3] [4]Cholesterol is biosynthesized by all animal cells [citation needed] and is an essential structural and signaling component of animal cell membranes.
The concept of permeability is of importance in determining the flow characteristics of hydrocarbons in oil and gas reservoirs, [4] and of groundwater in aquifers. [5]For a rock to be considered as an exploitable hydrocarbon reservoir without stimulation, its permeability must be greater than approximately 100 md (depending on the nature of the hydrocarbon – gas reservoirs with lower ...
Hypocholesterolemia is the presence of abnormally low (hypo-) levels of cholesterol in the blood (-emia). A defect in the body's production of cholesterol can lead to adverse consequences as well. Cholesterol is an essential component of mammalian cell membranes and is required to establish proper membrane permeability and fluidity.
At low pore humidities (<75%), shrinkage is caused by a decrease of the disjoining pressure across nano-pores less than about 3 nm thick, filled by adsorbed water. The chemical processes of Portland cement hydration lead to another type of shrinkage, called the autogeneous shrinkage, which is observed in sealed specimens, i.e., at no moisture loss.
HMG-CoA reductase (3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, official symbol HMGCR) is the rate-controlling enzyme (NADH-dependent, EC 1.1.1.88; NADPH-dependent, EC 1.1.1.34) of the mevalonate pathway, the metabolic pathway that produces cholesterol and other isoprenoids.
Cholesterol is the dynamic "glue" that holds the raft together. [3] Due to the rigid nature of the sterol group, cholesterol partitions preferentially into the lipid rafts where acyl chains of the lipids tend to be more rigid and in a less fluid state. [6] One important property of membrane lipids is their amphipathic character.
a table showing ranges of values of hydraulic conductivity and permeability for various geological materials. Values are for typical fresh groundwater conditions — using standard values of viscosity and specific gravity for water at 20 °C and 1 atm. See the similar table derived from the same source for intrinsic permeability values. [13]