Meselson and Stahl invented what new technique in their quest to prove that DNA replication is semi-conservative?
Meselson and Stahl devised the technique of density gradient centrifugation.
They grew bacteria in a medium containing a heavy isotope of nitrogen, 15N. After a few generations, some bacteria had DNA with only 15N in its bases. The researchers then placed some of these bacteria in a medium in which the only source of nitrogen was 14N. By centrifugation, the researchers could show that the DNA in the next generation of bacteria was intermediate in mass between DNA containing only 15N and DNA containing only 14N. This proved that the semi-conservative model was the correct model of DNA replication.
Meselson and Stahl conducted an experiment in 1958, and discovered that DNA replication was semiconservative. In semiconservative replication, when the double stranded DNA helix is replicated each of the two new double-stranded DNA helixes consisted of one strand from the original helix and one newly synthesized.
This is usually used in a medical or technological context. A pioneer is the first to do something. So if a doctor who invented a technique advertises that they are a pioneer in their field, then they are trying to imply that they should have more knowledge and experience on whatever technique because they did it the longest.
In the Renaissance, "Chiaroscuros" was invented as a drawing technique using coloured paper, where the artist worked from the paper's base tone towards light using white. From this light and dark technique was developed further to become a technique which is characterised by strong, bold contrasts between light and darkm affecting a whole composition making the composition more 'dramatic'.
Is it true that teriyaki sauce was invented for a Japanese racecar driver at the turn of the century?
Mohs Ambroise Pare was a French barber surgeon that was born in 1510 and died in 1590. During his lifetime he invented several surgical practices and instruments. Among his inventions was his development of the technique used for closing wounds with stitches that he used for helping treat soldiers that were wounded on the battlefield.