Kinetic deconjugation: a gateway to the synthesis of Xxx-Gly (E)-alkene dipeptide isosteres

A new method for the preparation of Xxx-Gly (E)-alkene dipeptide isosteres (EADIs), using LDA deprotonation followed by 1 N HCl quench, was explored. The method, named kinetic deconjugation, enabled the synthesis of Tyr-Gly, Gly-Gly, Ser-Gly, Pro-Gly, and Phe-Gly EADIs, as well as one Tyr-Gly trisubstituted alkene dipeptide isostere (TADI). Overall, this method, based on commercially available materials, leads to high yields, requires few synthetic steps and works on the gram scale in the synthesis of a wide variety of EADIs.     

Development,validation and application of a generator for distortion product otoacoustic emissions

The application area of distortion product otoacoustic emissions (DPOAEs) is expanding beyond clinical routines, towards new measurement environments, protocols, wearable hardware and more robust algorithms. To enable systematic assessment of the performance of commercial and prototype OAE equipment under various measurement conditions without a need for recruitment of the test subjects, a DPOAE generator that produces a reliable and stable response is proposed. This article suggests simple design for such generator that is easy to reproduce by third parties. This design uses an approximate model for middle and inner ear dynamics focusing on typical operational conditions. The DPOAE generator is embedded in a head and torso simulator enabling testing for various probe fitting and also residual ear canal volume effects. Measurement of the DPOAE generator response with clinical equipment shows that the response obtained falls within the range of human normative data. It is also shown that the generator is applicable outside the clinical routines and is able to highlight differences in measurements obtained with different clinical OAE measurement devices.