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Passage Materials: Rales are new sounds, not common to healthy lungs, and are created either in the bronchi, bronchioles, air vesicles or pathological cavities. They are due to a number of causes, the most frequent of which are (1) the passage materials of air through narrowed bronchi, such narrowing being the result of inflammation of the mucous membrane or of muscular spasm, and (2) the passage materials of air through or by a certain amount of fluid, either mucus, pus, blood serum, or combinations of these.
These latter finishes are subdivided into durable types, which resist removal by laundering or dry cleaning, and nondurable, or "retreatable," which require a fresh application after each cleaning.
Impermeable fabrics are most generally used for nonclothing purposes because for such uses they are usually more economical. They are made by filling the interstices between the fibers with varnish, pitch, resin, linseed oil, tar, paint and similar materials, which interpose a physical barrier to the passage materials of water.
Another problem concerning the bacterial envelope was the question of how large molecules containing up to seven amino acids and sugar residues could get across the cell membrane, which regulates the passage materials of materials into and out of the cell. It was discovered that these prefabricated building blocks become attached to a phosphorus-containing lipid and, in effect, dissolve in the lipid-rich membrane. It seems very likely that similar transferring lipids will be found in the cell membranes of higher organisms. |
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