Tuesday, February 26, 2013

History of Thiamine

Thiamine was the first vitamin to be discovered. Kanehiro Takaki, a Japanese naval doctor, was the first to report that beriberi seemed to be a nutritional deficiency based on reducing the incidence of beriberi in Japanese sailors by giving them additional meat, dry milk and vegetables.

Christiaan Eijkman, a Dutch military surgeon, who traveled to the Dutch East Indies to study beriberi, in 1890s began to clarify the role of diet in the development of beriberi.

Eijkman discovered that a disease similar to beriberi occurred in birds that were fed a diet of steam-cooked polished rice, as opposed to crude rice.

In 1926, thiamine was the first B vitamin isolated, as a crystalline, water soluble, yellowish white powder with a salty, slightly nutty taste. It was crystallized from rice polishing by two Dutch scientists Barend Jansen and W. F. Donald as antineuritic vitamin.

By 1936 it had been synthesized and its chemical structure determined by Robert R. Williams which he named ‘thiamine’.

The discovery of thiamine revolutionized the management of wet beriberi because thiamine quickly reversed the cardiac manifestations of the disease.
History of Thiamine

Friday, February 15, 2013

Discovery of chlorophyll

Chlorophyll is a green pigment found in almost all plants, algae and cyanobacteria. The chloro portion of the word chlorophyll is from the Greek chloros, which means yellowish green, and phyllon, which means leaf. 

Chlorophyll was first isolated by Joseph Bienaimé Caventou (1795-1877) and Pierre Joseph Pelletier (1788-1842) in 1817.

At the time of their work, scientists know that green plants consume carbon dioxide and release oxygen.

In 1883, German physiologist Julius von Sachs showed that chlorophyll is not scattered all around a plant cell but is found in special structures called chloroplasts. He is given credit for proving that chlorophyll is involved in photosynthesis.

Later work shows that chlorophyll is an essential chemical for photosynthesis to occur.

Chlorophyll a and b were purified by German scientist, Richard Willstatter in 1906-1914. Subsequently they were separated chromatographically in 1933.

Willstatter received a Nobel Prize in Chemistry in 1915 for his work in chlorophyll.

In 1965 a US scientist, Robert Burns Woodward, won a Noble Prize in Chemistry for figuring out the structure of the chlorophyll molecule.
Discovery of chlorophyll

Sunday, February 3, 2013

History of logarithm

Early Arab mathematicians took over the basic algorithms for calculations from India and around 950 Abu’l Hassan Ahmad ibn Ibrahim Al-Uqlidisi adapted them for use with pen and paper rather than traditions Indian dustboard.

Several mathematician of the sixteenth century had been playing with possibility of coordinating arithmetical and geometrical progressions, mainly in order to ease the work with the complicated trigonometrical tables. 

The most ingenious and enduring solutions was development of logarithms by the Scottish mathematicians John Napier in the early 17th century.

In 1614 the invention of logarithms burst upon the world with the publication of Napier’s A description of the admirable table of logarithms.

Publication of the system of logarithms was greeted with prompt recognition and among the most enthusiastic admirers was Henry Briggs, the first Savillian professor of geometry at Oxford and the first Gresham College professor of geometry.

Briggs proposed the system of common logarithms with base 10. From 1615 Briggs devoted the main part of his time to the construction of logarithmic tables.

Tables of logarithms were published first in 1620 by the Swiss mathematician Joost Burgi, who discovered logarithm independently of Napier between 1603 and 1611.
History of logarithm
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