Porous junctions called intercalated discs form junctions between the cells. Its sediments consist mainly of shales and greywackes with intercalated rhyolites and carbonates. It has long striated ducts and short intercalated ducts. The gland has short, striated ducts and long, intercalated ducts. The material is composed of cobalt oxide layers with the lithium intercalated. Old papers were unearthed in which researchers tried to isolate graphene starting with intercalated compounds. The bond between the carbon and fluorine atoms is covalent, thus fluorine is not intercalated. Electrical resistance through intercalated discs is very low, thus allowing free diffusion of ions. Tertiary spirals are intercalated between the preceding groups in more specialized species. Nephron remodeling increases the number of distal convoluted cells, principle cells, and intercalated cells. Two layers of Na can be intercalated in between MXene layers. Historically, lunisolar calendars intercalated entire leap months on an observational basis. A complex magnesium(I) species has also been intercalated into graphite. Striated and intercalated ducts are also present. Under electron microscopy, an intercalated disc's path appears more complex.