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A phenocryst is an early forming, relatively large and usually conspicuous crystal distinctly larger than the grains of the rock groundmass of an igneous rock. Such rocks that have a distinct difference in the size of the crystals are called porphyries, and the adjective porphyritic is used to describe them.
Neuroplasticity is the process by which neurons adapt to a disturbance over time, and most often occurs in response to repeated exposure to stimuli. [27] Aerobic exercise increases the production of neurotrophic factors [note 1] (e.g., BDNF, IGF-1, VEGF) which mediate improvements in cognitive functions and various forms of memory by promoting blood vessel formation in the brain, adult ...
Corpora arenacea (singular: corpus arenaceum, [1] also called brain sand or acervuli [2] [3] or psammoma bodies [4] or pineal concretions [4]) are calcified structures in the pineal gland and other areas of the brain such as the choroid plexus. Older organisms have numerous corpora arenacea, whose function, if any, is unknown.
It is likely that such effects have an effect on the blood supply to the brain. That such an effect might well lead to damage to the brain seems likely. Therefore it is regarded that the association between exposure to air pollutants and effects on cognitive decline and dementia as likely to be causal with respect to this mechanism. [65]
The effects of early-life exposures to anesthesia on the brain in humans are controversial. Evidence from nonhuman primate research suggests significant developmental neurotoxicity and long-term social impairment, with a dose–response relationship where repeated exposures cause a more severe impact than single ones.
It is not known what the effects are from long-term ingestion or skin contact with low levels of cresols. The Occupational Safety and Health Administration has set a permissible exposure limit at 5 ppm (22 mg/m 3 ) over an eight-hour time-weighted average, while the National Institute for Occupational Safety and Health recommends a limit of 2.3 ...
It crystallizes in the monoclinic system, usually as long prismatic crystals showing a diamond-shaped cross section, but also in fibrous, bladed, acicular, columnar, and radiating forms. Its Mohs hardness is 5.0–6.0, and its specific gravity is 3.0–3.4.
Blue light, a type of high-energy light, is part of the visible light spectrum. High-energy visible light (HEV light) is short-wave light in the violet/blue band from 400 to 450 nm in the visible spectrum, which has a number of purported negative biological effects, namely on circadian rhythm and retinal health (blue-light hazard), which can lead to age-related macular degeneration.