<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">M. Xu</style></author><author><style face="normal" font="default" size="100%">D. George</style></author><author><style face="normal" font="default" size="100%">R. Jimenez</style></author><author><style face="normal" font="default" size="100%">A. Markelz</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Photo-Switching of Protein Dynamical Collectivity</style></title><secondary-title><style face="normal" font="default" size="100%">Photonics</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2021</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.mdpi.com/2304-6732/8/8/302</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">8</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p class=&quot;rtejustify&quot;&gt;We examine changes in the picosecond structural dynamics with irreversible photobleaching of red fluorescent proteins (RFP) mCherry, mOrange2 and TagRFP-T. Measurements of the protein dynamical transition using terahertz time-domain spectroscopy show in all cases an increase in the turn-on temperature in the bleached state. The result is surprising given that there is little change in the protein surface, and thus, the solvent dynamics held responsible for the transition should not change. A spectral analysis of the measurements guided by quasiharmonic calculations of the protein absorbance reveals that indeed the solvent dynamical turn-on temperature is independent of the thermal stability/photostate however the protein dynamical turn-on temperature shifts to higher temperatures. This is the first demonstration of switching the protein dynamical turn-on temperature with protein functional state. The observed shift in protein dynamical turn-on temperature relative to the solvent indicates an increase in the required mobile waters necessary for the protein picosecond motions, that is, these motions are more collective. Melting-point measurements reveal that the photobleached state is more thermally stable, and structural analysis of related RFP’s shows that there is an increase in internal water channels as well as a more uniform atomic root mean squared displacement. These observations are consistent with previous suggestions that water channels form with extended light excitation providing O&lt;sub&gt;2 &lt;/sub&gt;access to the chromophore and subsequent fluorescence loss. We report that these same channels increase internal coupling enhancing thermal stability and collectivity of the picosecond protein motions. The terahertz spectroscopic characterization of the protein and solvent dynamical onsets can be applied generally to measure changes in collectivity of protein motions.&lt;/p&gt;
</style></abstract><section><style face="normal" font="default" size="100%">302</style></section></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>10</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Y. Deng</style></author><author><style face="normal" font="default" size="100%">K. Niessen</style></author><author><style face="normal" font="default" size="100%">A. Markelz</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Angular Distortion Removal of THz Anisotropic Dichroism Microscope</style></title><secondary-title><style face="normal" font="default" size="100%">2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves</style></secondary-title><short-title><style face="normal" font="default" size="100%">2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)</style></short-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">absorption</style></keyword><keyword><style  face="normal" font="default" size="100%">angular distortion removal</style></keyword><keyword><style  face="normal" font="default" size="100%">Biomedical measurement</style></keyword><keyword><style  face="normal" font="default" size="100%">continuous iso-response curve</style></keyword><keyword><style  face="normal" font="default" size="100%">detection light polarizations</style></keyword><keyword><style  face="normal" font="default" size="100%">discontinuous iso-response angle pairs</style></keyword><keyword><style  face="normal" font="default" size="100%">Distortion</style></keyword><keyword><style  face="normal" font="default" size="100%">light polarisation</style></keyword><keyword><style  face="normal" font="default" size="100%">material characterization</style></keyword><keyword><style  face="normal" font="default" size="100%">Microscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">proteins</style></keyword><keyword><style  face="normal" font="default" size="100%">rapid anisotropic terahertz spectroscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">relative polarizations</style></keyword><keyword><style  face="normal" font="default" size="100%">spectroscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">stationary sample</style></keyword><keyword><style  face="normal" font="default" size="100%">terahertz spectroscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">terahertz wave spectra</style></keyword><keyword><style  face="normal" font="default" size="100%">THz anisotropic dichroism microscope</style></keyword><keyword><style  face="normal" font="default" size="100%">vibrations</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2019</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2019</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://ieeexplore.ieee.org/document/8873793</style></url></web-urls></urls><pub-location><style face="normal" font="default" size="100%">Paris, France</style></pub-location><pages><style face="normal" font="default" size="100%">1 - 2</style></pages><isbn><style face="normal" font="default" size="100%">2162-2035</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;We have developed a stationary sample THz anisotropic dichroism microscope as a powerful tool for material characterization. The key innovation is the use of an iso-response curve defined by the terahertz and detection light polarizations. Here we show that following a continuous iso-response curve introduces angular distortion in the spectrum, and this distortion can be eliminated by using a discontinuous iso-response angle pairs avoiding large gradient regions. Employing this additional constraint on the relative polarizations provides a convenient technique for rapid anisotropic terahertz spectroscopy.&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>10</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">D. Wolpert</style></author><author><style face="normal" font="default" size="100%">W. Cox</style></author><author><style face="normal" font="default" size="100%">J. Cerne</style></author><author><style face="normal" font="default" size="100%">A. Markelz</style></author><author><style face="normal" font="default" size="100%">T. Zhao</style></author><author><style face="normal" font="default" size="100%">R. Ramesh</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Romanowicz M.</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Finite size effects in ferroelectric nanosystems: Absence of mode softening</style></title><secondary-title><style face="normal" font="default" size="100%">2003 Nanotechnology Conference and Trade Show - Nanotech</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Ferroelectric materials</style></keyword><keyword><style  face="normal" font="default" size="100%">Fourier Transform Infrared Spectroscopy</style></keyword><keyword><style  face="normal" font="default" size="100%">Frequency ranges</style></keyword><keyword><style  face="normal" font="default" size="100%">Lead compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Mode softening</style></keyword><keyword><style  face="normal" font="default" size="100%">nanostructured materials</style></keyword><keyword><style  face="normal" font="default" size="100%">Natural frequencies</style></keyword><keyword><style  face="normal" font="default" size="100%">Optical modes</style></keyword><keyword><style  face="normal" font="default" size="100%">Permittivity</style></keyword><keyword><style  face="normal" font="default" size="100%">phase transitions</style></keyword><keyword><style  face="normal" font="default" size="100%">phonons</style></keyword><keyword><style  face="normal" font="default" size="100%">Routers</style></keyword><keyword><style  face="normal" font="default" size="100%">Thermal effects</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2003</style></year><pub-dates><date><style  face="normal" font="default" size="100%">02/2003</style></date></pub-dates></dates><pub-location><style face="normal" font="default" size="100%">San Francisco, CA</style></pub-location><volume><style face="normal" font="default" size="100%">2</style></volume><pages><style face="normal" font="default" size="100%">76-81</style></pages><isbn><style face="normal" font="default" size="100%">0972842209</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;We present measurements of the mode softening behavior for PbZr 0.5Ti0.5O3 (PZT(50)) thin films using terahertz time domain spectroscopy (TTDS). The films were grown using pulsed laser deposition (PLD) techniques on silicon substrates to study how reduced size affects the mode softening behavior. At room temperature two modes are observed at 1.1 THz (37 cm-1) and at 2.3 THz (77 cm-1). As the temperature is increased toward Tc we do not see strong mode softening, but rather a spectral weight transfer from the high frequency mode to the low frequency mode. This absence of mode softening is more dramatic than that reported by other investigators[1]. We will discuss the possible sources for this discrepancy. These results suggest a change in lattice dynamics for nanoscale ferroelectric films that may be highly dependent on the sample preparation technique.&lt;/p&gt;</style></abstract><notes><style face="normal" font="default" size="100%">cited By 0</style></notes></record></records></xml>