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The term "compound atom" was confusing to some of Dalton's contemporaries as the word "atom" implies indivisibility, but he responded that if a carbon dioxide "atom" is divided, it ceases to be carbon dioxide. The carbon dioxide "atom" is indivisible in the sense that it cannot be divided into smaller carbon dioxide particles. [4] [19]
Sir Alexander Fleming FRS FRSE FRCS [2] (6 August 1881 – 11 March 1955) was a Scottish physician and microbiologist, best known for discovering the world's first broadly effective antibiotic substance, which he named penicillin.
1929: Alexander Fleming: Penicillin, the first beta-lactam antibiotic; 1929: Lars Onsager's reciprocal relations, a potential fourth law of thermodynamics; 1930: Subrahmanyan Chandrasekhar discovers his eponymous limit of the maximum mass of a white dwarf star; 1931: Kurt Gödel: incompleteness theorems prove formal axiomatic systems are incomplete
Some view the birth of quantum chemistry in the discovery of the Schrödinger equation and its application to the hydrogen atom in 1926. [ citation needed ] However, the 1927 article of Walter Heitler and Fritz London [ 5 ] is often recognised as the first milestone in the history of quantum chemistry.
Thomas Hunt Morgan identifies a sex chromosome linked gene in Drosophila melanogaster (1910) and his student Alfred Sturtevant develops the first genetic map (1913). Alexander Fleming demonstrates that the zone of inhibition around a growth of penicillin mould on a culture dish of bacteria is caused by a diffusible substance secreted by the ...
Molecular phylogeny has established that Alexander Fleming's first discovered penicillin producing strain is of a distinct species, P. rubens, and not of P. notatum. [4] [5] It has rarely been reported as a cause of human disease. [6] It is the source of several β-lactam antibiotics, most significantly penicillin.
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Sample of penicillin mould presented by Alexander Fleming to Douglas Macleod in 1935. The discovery of penicillin was one of the most important scientific discoveries in the history of medicine. Ancient societies used moulds to treat infections and in the following centuries many people observed the inhibition of bacterial growth by moulds.