Active Ingredient: Doxycycline
It inhibits the synthesis of bacterial proteins by binding to the 30 S ribosomal subunit, which is only found in bacteria.
This stops bacterial growth giving the immune system time to kill and remove the bacteria.
American Cyanamid was one of these, and in the late 1940 s chemists there discovered chlortetracycline, the first member of the tetracycline class of antibiotics.
Both compounds, like penicillin, were natural products and it was commonly believed that nature had perfected them, and further chemical changes could only degrade their effectiveness.
Scientists at Pfizer led by Lloyd Conover modified these compounds, which led to the invention of tetracycline itself, the first semi-synthetic antibiotic. Charlie Stephens' group at Pfizer worked on further analogs and created one with greatly improved stability and pharmacological efficacy: doxycycline.
It was clinically developed in the early 1960 s and approved by the FDA in 1967.
Bartok uses the chromatic sets eg. However instead of utilising the chromatic possibilities in the set, Bartok plays mirror games, alternating between pitches.
This is seen throughout the movement VIn mm.
In mm. The overall set effect of movement towards the central axis.
In contrast, in mm. Using the overlap of the two central pitches G and F there is an overall set effect of movement outwards to the ends of the set which is emphasised by the initial A-E chord on mm.
A graph was made for statistical purposes showing the frequency of the pitch class sets that were segmented in the movement. The top five are as follows PCSet Freq 6- 14 -6 7 7-5 6 4- 6 4-1 4 Set 6- had the most number of occurrences.
This is attributed to the fact that it was used on numerous occasions as a chord pedal but most noticeably at the beginning of the movement mm.
It is worth mentioning that although set 6- is used eg.
However the spacings of the accompanying chord pedal are usually wide eg. Another trend to note from the PCSet frequency table is that eighty percent of the top five sets are symmetrical.
As in most tonal music, Bartok uses cadences at the end of sections. In the absence of keys and modulations, there are particular pitch class collections that are used cadentially or as a final chord to end a particular section.
These articulations and instrumentational groupings underpinned many of the decisions in segmenting the work.
Throughout the movement the accompaniment has a specific articulation as a distinguishing characteristic eg. Other examples where paired articulation specifications denote the solo or accompaniment texture is in mm.
Again in mm. The beginning of Section B mm. This is emphasised by the unprecedented pizzicato texture change and use of sul ponticello from mm. Utilising the Golden mean 0.