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This type of thrombolites is composed of small openings that trap fine-grained sediments. They are also known "thrombolitic-stromatolites" due to their close relation with the same composition of stromatolites. Because they trap sediment, their formation is linked to the rise of algal-cyanobacterial mats. [3]
Oncolites are very similar to stromatolites, but, instead of forming columns, they form approximately spherical structures. [1] The oncoids often form around a central nucleus, such as a shell fragment, [ 2 ] and a calcium carbonate structure is deposited by encrusting microbes .
Scientists have argued for a biological origin of stromatolites due to the presence of organic globule clusters within the thin layers of the stromatolites, of aragonite nanocrystals (both features of current stromatolites), [18] and of other microstructures in older stromatolites that parallel those in younger stromatolites that show strong ...
The stromatolites found today are almost all carbonate rocks (made of limestone), but these structures are mostly composed of the minerals gypsum and halite (rock salt), Hynek said.
Cerebral infarction, also known as an ischemic stroke, is the pathologic process that results in an area of necrotic tissue in the brain (cerebral infarct). [1] In mid to high income countries, a stroke is the main reason for disability among people and the 2nd cause of death. [2]
The blood–brain barrier is formed by the brain capillary endothelium and excludes from the brain 100% of large-molecule neurotherapeutics and more than 98% of all small-molecule drugs. [28] Overcoming the difficulty of delivering therapeutic agents to specific regions of the brain presents a major challenge to treatment of most brain disorders.
The cerebral cortex, also known as the cerebral mantle, [1] is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals.It is the largest site of neural integration in the central nervous system, [2] and plays a key role in attention, perception, awareness, thought, memory, language, and consciousness.
Cerebral softening, also known as encephalomalacia, is a localized softening of the substance of the brain, due to bleeding or inflammation. Three varieties, distinguished by their color and representing different stages of the disease progress, are known respectively as red, yellow, and white softening.