Isolated bovine adrenal chromaffin cells exposed to single 2-, 4-, or 5-ns pulses undergo a rapid, transient rise in intracellular Ca mediated by Ca entry via voltage-gated Ca channels (VGCCs), mimicking the activation of these cells in vivo by acetylcholine. However, pulse durations 150 ns or longer elicit larger amplitude and longer-lived Ca responses due to Ca influx via both VGCCs and a yet to be identified plasma membrane pathway(s). To further our understanding of the differential effects of ultrashort versus longer pulse durations on Ca influx, chromaffin cells were loaded with calcium green-1 and exposed to single 3-, 5-, 11-, 25-, or 50-ns pulses applied at their respective Ca activation threshold electric fields.
View Article and Find Full Text PDFWe demonstrate local phonon analysis of single AlN nanocrystals by two complementary imaging spectroscopic techniques: tip-enhanced Raman scattering (TERS) and nano-Fourier transform infrared (nano-FTIR) spectroscopy. Strong surface optical (SO) phonon modes appear in the TERS spectra with their intensities revealing a weak polarization dependence. The local electric field enhancement stemming from the plasmon mode of the TERS tip modifies the phonon response of the sample, making the SO mode dominate over other phonon modes.
View Article and Find Full Text PDFJ Phys Condens Matter
May 2021
The Shubnikov de Haas (SdH) effect measurements have been performed to evaluate the influence of SiNpassivation, a spacer layer, and Si-doped barrier layer on the electronic transport parameters of two-dimensional (2D) electrons in AlGaN/AlN/GaN heterostructures under temperatures from 1.8 K to 40 K and at a magnetic field up to 11 T. The 2D electron effective mass (*), 2D carrier density (), the difference between Fermi level and subband energy levels (-), quantum lifetime () are determined by analyzing SdH oscillations.
View Article and Find Full Text PDFDetergent resistance of erythrocytes and viscosity of whole blood altered sharply already on the first stages of spectrin denaturation process (46-48 degrees C). Alternatively, deformability changes arise above 50 degrees C. Further insignificant increase in viscosity proceeded above 50 degrees C.
View Article and Find Full Text PDF