Sunday, June 23, 2013
Winlicenus' research was in organic chemistry. Starting in 1868 he began studying lactic acid. Lactic acid is a carboxylic acid that is a metabolite of glucose. In his studies he found that there were two types of lactic acid which had different chemical properties. While these two chemicals have the same chemical formula (the same numbers and types of atoms) they have different structures. In the case of lactic acid (a three carbon long carboxylic acid) one form has a hydroxyl group attached to the carbon adjacent to the carbonyl carbon and the other form has a hydroxyl group attached to the terminal carbon, the carbon on the opposite end of the three carbon chain from the carbonyl. Because these two molecules have different structures they have different properties, but the formulas for both compounds are both C3H6O3. Winlicenus called these chemicals with the same formula but different structures structural isomers.
Another important experiment carried out by Winlicenus, working in collaboration with his friend Aldolf Fick a professor of physiology at the University of Zurich, showed that carbohydrates and fats were the principal source of muscular energy. The pair ascended the Faulhorn, taking with them only food from which proteins had been excluded. While they climbed the pair monitored their nitrogen metabolism and found that the the break down of proteins accounted for less than one third of the energy generated by their metabolism.
Wislicenus was elected a foreign member of the British Royal Chemical Society in 1888 and member of the Royal Society of London in 1897 which presented him with its Davy Medal in the following year.
Winlicenus died on December 5, 1902.
P.F.F.; "Johannes Wislicenus. 1835-1902"; Proceedings of the Royal Society (1907) 78:iii-xii
Ramberg, Peter J.; Chemical Structure, Spatial Arrangement: An Early History of Stereochemistry. 1874-1914; Ashgate Publishing Ltd.; 2003
"Johannes Wislicenus, Biography", retrieved from: my.rsc.org
Johannes Wislicenus Wikipedia Entry
Sunday, June 9, 2013
Cassini is probably best remembered for discovering the Cassini Division, a open space between Saturn's A and B rings. Before Cassini it was believed that the rings of Saturn were one large solid ring structure orbiting the planet. Cassini's observations of the rings showed that there were breaks between the rings. We know now that the rings of Saturn are not solid at all, but made up of orbiting pieces of ice and debris. Cassini was also responsible for identifying four of the moons orbiting Saturn: Iapetus, Rhea, Tethys, and Dione. Cassini also shares credit for discovering the red spot on Jupiter with English scientist Robert Hooke Although Cassini initially believed in a geocentric model for the solar system he eventually came to believe in a solarcentric model, similar to that proposed by Nicolas Copernicus.
In addition to craters on the moon and Mars named after him Cassini also has an asteroid named after him. Additionally NASA's unmanned probe that is currently exploring Saturn and its moons is named after him (for more information on the Cassini probe see here).
As he grew older Cassini's vision failed him and his son Jacques began to run the Paris Observatory. Cassini died on December 14, 1712.
Connor, Elizabeth; "The Cassini Family and the Paris Observatory"; Astronomical Society of the Pacific Leaflets (1947)218:146-153
O'Connor, J.J. and Robertson, E.F.; "Giovanni Domenico Cassini"; Retrieved from: history.mcs.st-anderews.ac.uk
Giovanni Domenicao Cassini Wikipedia Entry
Sunday, June 2, 2013
In 1903 he was appointed professor of pharmacology at the University of Graz in Austria. While working at Graz he conducted an experiment that proved that the transmission of nerve impulses to the heart was conducted by a soluble factor, the idea for which came to him in a dream. First he isolated two frog hearts, one with the vagus nerve still attached. The vagus nerve is part of the parasympathetic nervous system and causes the heart muscle to slow its beating. First he stimulated the attached vagus nerve, which caused the attached heart to slow its beating. Taking a sample of the fluid surrounding the heart with the attached nerve he applied it to the second heart. The second heart slowed its beating in response to the added fluid. Loewi named the unknown soluble factor that caused the second heart to slow its beating "vagustoff". It was later identified as acetylcholine. The transmission of nerve impulses between different neurons and at the nerve interfaces with muscles are conducted by soluble chemicals called neurotransmitters. For his pioneering work establishing the importance of neurotransmitters Loewi shared the 1936 Nobel Prize in medicine and physiology with Henry Dale. He would remain in Austria until 1938 when he was forced to leave due to the German occupation. After a brief stays in Belgium and the United Kingdom, Loewi emigrated to the United States in 1940
Other honors won by Loewi include honorary doctorates from the University of Graz, Yale University, University of New York (where he worked after he emigrated to the United States) and the University of Frankfurt. He was made an honorary member of the Physiological Society of London and a member of the Royal Society.
Loewi died on December 25, 1961.
Valenstein, Elliot S.; The War of Soups and the Sparks: The Discovery of Neurotransmitters and the Dispute Over How Nerves Communicate; Columbia University Press; 2005
Otto Loewi Nobel Biography
Ottto Loewi Wikipedia Entry