Rhodopsin (also known as visual purple) is a light-sensitive receptor protein involved in visual phototransduction. It is named after ancient Greek ῥόδον (rhódon) for rose, due to its pinkish color, and ὄψις (ópsis) for sight. Rhodopsin is a biological pigment found in the rods of the retina and is a G-protein-coupled receptor (GPCR). It belongs to a group of photoswitchable opsins. Rhodopsin is extremely sensitive to light, and thus enables vision in low-light conditions. When rhodopsin is exposed to light, it immediately photobleaches. In humans, it is regenerated fully in about 30 minutes, after which rods are more sensitive.
Rhodopsin was discovered by Franz Christian Boll in 1876.
Zen (Chinese: 禪; pinyin: Chán; Japanese: 禅, romanized: zen; Korean: 선, romanized: Seon; Vietnamese: Thiền) is a school of Mahayana Buddhism that originated in China during the Tang dynasty, known as the Chan School (Chánzong 禪宗), and later developed into various sub-schools and branches. From China, Chán spread south to Vietnam and became Vietnamese Thiền, northeast to Korea to become Seon Buddhism, and east to Japan, becoming Japanese Zen. The term Zen is derived from the Japanese pronunciation of the Middle Chinese word 禪 (chán), an abbreviation of 禪那 (chánnà), which is a Chinese transliteration of the Sanskrit word dhyāna ("meditation"). Zen emphasizes rigorous self-restraint, meditation-practice, insight into the nature of mind (見性, Ch. jiànxìng, Jp. kensho, "perceiving the true nature") and nature of things (without arrogance or egotism), and the personal expression of this insight in daily life, especially for the benefit of others. As such, it de-em