Dorothy Mary Crowfoot Hodgkin OM FRS HonFRSC.docx - Dorothy...

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Dorothy Mary Crowfoot Hodgkin OM FRS HonFRSC [10] [11] (12 May 1910 – 29 July 1994) was a British chemist who developed protein crystallography , for which she won the Nobel Prize in Chemistry in 1964. [10] [12] She advanced the technique of X-ray crystallography , a method used to determine the three- dimensional structures of molecules. Among her most influential discoveries are the confirmation of the structure of penicillin as previously surmised by Edward Abraham and Ernst Boris Chain , and the structure of vitamin B 12 , for which she became the third woman to win the Nobel Prize in Chemistry. In 1969, after 35 years of work, Hodgkin was able to decipher the structure of insulin . [13] She is regarded as one of the pioneer scientists in the field of X-ray crystallography studies of biomolecules , which became an essential tool in the field of structural biology .
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Sodium cyclamate (sweetener code 952) is an artificial sweetener . It is 30–50 times sweeter than sucrose (table sugar), making it the least potent of the commercially used artificial sweeteners. It is often used with other artificial sweeteners, especially saccharin ; the mixture of 10 parts cyclamate to 1 part saccharin is common and masks the off-tastes of both sweeteners. [1] It is less expensive than most sweeteners, including sucralose , and is stable under heating. Safety concerns have led to cyclamates being banned in the United States and other countries, though the European Union recognizes them as safe. Sodium cyclamate, commonly known as simply as cyclamate, is an artificial sweetener, used as a sugar substitute. The sweet taste of cyclamate was discovered by accident. In 1937, a student named Michael Sveda at the University of Illinois. While working on synthesising medicines, he put the cigarette he was smoking on the bench; when he put it back in his mouth he noticed the sweet taste. It was originally marketed in tablet form, and recommended for use as a tabletop sweetener for diabetics. It was one of the most widely used sugar substitutes, and at around 30 -50 times sweeter than sugar is one the least potent of the artificial sweeteners. It is commonly used in soft drinks, often in combination with other sugar substitutes such as saccharine. It is approved as a sweetener in over 55 countries.
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Osmium has a blue-gray tint and is the densest stable element ; it is approximately twice as dense as lead [3] and slightly denser than iridium . [6] Calculations of density from the X-ray diffraction data may produce the most reliable data for these elements, giving a value of 22.587±0.009 g/cm 3 for osmium, slightly denser than the 22.562±0.009 g/cm 3 of iridium; both metals are nearly 23 times as dense as water. [7] Osmium is a hard but brittle metal that remains lustrous even at high temperatures. It has a very low compressibility . Correspondingly, its bulk modulus is extremely high, reported between 395 and 462 GPa , which rivals that of diamond (443 GPa). The hardness of osmium is moderately high at 4 GPa.
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