https://www.selleckchem.com/products/Cyclopamine.html Telecommunication devices exploit hypersonic gigahertz acoustic phonons to mediate signal processing with microwave radiation, and charge carriers to operate various microelectronic components. Potential interactions of hypersound with charge carriers can be revealed through frequency- and momentum-resolved studies of acoustic phonons in photoexcited semiconductors. Here, we present an all-optical method for excitation and frequency-, momentum-, and space-resolved detection of gigahertz acoustic waves in a spatially confined model semiconductor. Lamb waves are excited in a bare silicon membrane using femtosecond optical pulses and detected with frequency-domain micro-Brillouin light spectroscopy. The population of photoexcited gigahertz phonons displays a hundredfold enhancement as compared with thermal equilibrium. The phonon spectra reveal Stokes-anti-Stokes asymmetry due to propagation, and strongly asymmetric Fano resonances due to coupling between the electron-hole plasma and the photoexcited phonons. This work lays the foundation for studying hypersonic signals in nonequilibrium conditions and, more generally, phonon-dependent phenomena in photoexcited nanostructures.BY-kinases represent a highly conserved family of protein tyrosine kinases unique to bacteria without eukaryotic orthologs. BY-kinases are regulated by oligomerization-enabled transphosphorylation on a C-terminal tyrosine cluster through a process with sparse mechanistic detail. Using the catalytic domain (CD) of the archetypal BY-kinase, Escherichia coli Wzc, and enhanced-sampling molecular dynamics simulations, isothermal titration calorimetry and nuclear magnetic resonance measurements, we propose a mechanism for its activation and nucleotide exchange. We find that the monomeric Wzc CD preferentially populates states characterized by distortions at its oligomerization interfaces and by catalytic element conformations that allow high-affinity