Mikhail Semyonovich Tsvet was born on this day in 1872.
Here’s an excerpt from Discoveries in Medicine about the significance of Tsvet’s work:
The first chromatograph was invented by Russian botanist Mikhail Semenovich Tsvett (1872-1919). While working in Poland, Tsvett was looking for a method of separating a mixture of plant pigments (tints) which are chemically very similar to each other. To isolate different types of chlorophyll, he trickled a mixture of dissolved pigments through a glass tube packed with calcium carbonate powder. As the solution washed downward, each pigment stuck to the powder with a different degree of strength, creating a series of colored bands. Each band of color represented a different substance. Tsvett referred to the colored bands as a chromatogram. He also suggested that the technique (now called adsorption chromatography) could be used to separate colorless substances.
Although Tsvett published a report of his work in the early 1900s, chemists paid very little attention to it. There were a few reasons for ignoring the work. First, the report was written in Russian, which few Western chemists of the time read. Second, the technique may have seemed too simple to chemists who were used to relying on lengthy extraction, crystallization, or distillation processes to separate mixtures. Within a few years, Tsvett’s technique was rediscovered. The rediscovery was by the German organic chemist Richard Martin Willstatter (1872-1942), who was also studying chlorophyll. By introducing chromatography to Western European scientists, Willstatter helped establish one of the most versatile analytical techniques known to chemistry.
Join us today as we honor the work of Mikhail Semyonovich Tsvet
A variety of genetic, metabolic, developmental, and idiopathic causes can result in congenital clouding of the cornea. A common reason for congenital clouding of the cornea is congenital glaucoma. Other major causes of corneal clouding include the following: Birth trauma Peters anomaly Dermoid tumors (limbal dermoids) Sclerocornea Congenital hereditary endothelial dystrophy (CHED) Mucopolysaccharidoses Infectious/inflammatory processes The following is a mnemonic for the causes of congenital clouding of the cornea: S – Sclerocornea T – Tears in the Descemet membrane secondary to birth trauma or congenital glaucoma U – Ulcers M – Metabolic P – Peters anomaly E – Edema (CHED) D – Dermoid Other rarer causes of congenital clouding of the cornea include the following: cornea plana, corneal keloids, oculoauriculovertebral (OAV) dysplasia (Goldenhar-Gorlin syndrome), congenital corneal ectasia, congenital hereditary stromal dystrophy, posterior polymorphous dystrophy, and Fryns syndrome.
piece about how ants let other ants know whether they are dead or not.
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