Mole (unit) measure the amount of substance (although in practice it is usual). There are many physical relationships between amount of substance and other physical quantities, the most notable one being the ideal gas law (where the relationship was first demonstrated in 1857). The term "mole" was first used in a textbook describing these colligative properties. Chemical engineers use the unit extensively, and decimal multiples may be more suitable for industrial use. For convenience in avoiding conversions in the imperial (or American customary units), some engineers adopted the "pound-mole" (notation "lb-mol" or "lbmol"), which is defined as the number of entities in
Ground substance as hyaluronic acid, heparan sulfate, dermatan sulfate, and chondroitin sulfate, proteoglycans which GAGs are bound to, and glycoproteins. Components of the ground substance are secreted by fibroblasts. Usually it is not visible on slides, because it is lost during staining in the preparation process. Link proteins such as vinculin, spectrin and actomyosin stabilize the proteoglycans and organize elastic fibers in the ECM. Changes in the density of ground substance can allow collagen fibers to form aberrant cross-links. Loose connective tissue is characterized by few fibers and cells, and a relatively large amount of ground substance. Dense connective tissue has a