02151nas a2200313   4500008004500000020001400045245007700059210006900136300001400205490000700219520129600226653001401522653002601536653001701562653003301579653001301612653001401625653001601639653001201655653001201667653001701679653002001696653001501716653001001731100001401741700001301755700002001768856004901788       2012                        Engldsh    a1463-907600aHydration and temperature interdependence of protein picosecond dynamics0 aHydration and temperature interdependence of protein picosecond   a6375-63810 v143 a<p>We investigate the nature of the solvent motions giving rise to the rapid temperature dependence of protein picoseconds motions at 220 K, often referred to as the protein dynamical transition. The interdependence of picoseconds dynamics on hydration and temperature is examined using terahertz time domain spectroscopy to measure the complex permittivity in the 0.2-2.0 THz range for myoglobin. Both the real and imaginary parts of the permittivity over the frequency range measured have a strong temperature dependence at &gt;0.27 h (g water per g protein), however the permittivity change is strongest for frequencies &lt;1 THz. The temperature dependence of the real part of the permittivity is not consistent with the relaxational response of the bound water, and may reflect the low frequency protein structural vibrations slaved to the solvent excitations. The hydration necessary to observe the dynamical transition is found to be frequency dependent, with a critical hydration of 0.19 h for frequencies &gt;1 THz, and 0.27 h for frequencies &lt;1 THz. The data are consistent with the dynamical transition solvent fluctuations requiring only clusters of similar to 5 water molecules, whereas the enhancement of lowest frequency motions requires a fully spanning water network.</p>10aChemistry10adielectric-relaxation10afluctuations10ainelastic neutron-scattering10alysozyme10amyoglobin10apercolation10aPhysics10aspectra10aspectroscopy10aterahertz beams10atransition10awater1 aLipps, F.1 aLevy, S.1 aMarkelz, A., G.  uhttps://markelz.physics.buffalo.edu/node/23302295nas a2200289   4500008004500000020001400045245010500059210006900164260000800233300001600241490000800257520142900265653001401694653002301708653002401731653001301755653002201768653002201790653002901812653001701841653002001858653002701878653002001905100001501925700001601940856004901956       2010                        Engldsh    a1520-610600aHydration Effects on Energy Relaxation of Ferric Cytochrome C Films after Soret-Band Photoexcitation0 aHydration Effects on Energy Relaxation of Ferric Cytochrome C Fi  cNov  a15151-151570 v1143 a<p>Protein hydration plays a critical role in protein dynamics and biological processes. Pump-probe transmission measurement has been applied to investigate the hydration effects on the energy relaxation of a heme protein ferric Cytochrome c (Cyt c) film after soret-band photoexcitation. Transient dynamics study indicates that the energy internal conversion time of similar to 300 fs is independent of hydration. The vibrationally excited electronic ground-state recovery rates show two transitions at the hydration level of h = 12.4-16.5% and 21.7-23.5%. The first transition occurs at the hydration level for the onset of an increasing ferric Cyt c flexibility while the second transition occurs at the saturated hydration level. The hydration dependence of steady-state electronic absorption spectrum results shows that the Q-band peak is nearly constant in center wavelength, but the line width surprisingly narrows with increasing hydration. For the similar to 695 nm absorbance associated with the MET80-Fe bond, the intensity increases with increasing hydration and slightly blue shifts. The 695 nm peak grows rapidly at h = 12.4% and then plateaus at h = 21.7%. This research shows that similar to 695 nm absorbance and ground-state recovery rates are sensitive to the hydration of the protein. This study will aid in understanding how hydration modulates the activity of the protein dynamics at a local level.</p>10aChemistry10acircular-dichroism10aconformation change10adynamics10aferricytochrome-c10aprotein hydration10aresolved resonance raman10aspectroscopy10aunfolded states10avibrational-relaxation10awater-molecules1 aYe, S., J.1 aMarkelz, A.  uhttps://markelz.physics.buffalo.edu/node/27400473nas a2200145   4500008004100000020001400041245007700055210006900132300001400201490000700215100001700222700001900239700002000258856004900278       2006                        eng d  a0006-349500aHydration dependence of conformational dielectric relaxation of lysozyme0 aHydration dependence of conformational dielectric relaxation of   a2576-25810 v901 aKnab, Joseph1 aChen, Jing-Yin1 aMarkelz, Andrea  uhttps://markelz.physics.buffalo.edu/node/18901708nas a2200433   4500008004100000245007100041210006900112250001900181260003200200300001400232490000700246520024500253653001200498653002200510653002900532653004000561653002200601653002100623653003500644653004500679653004500724653003400769653004400803653003500847653002700882653002100909653001200930653002200942653002300964653001400987653003201001653001701033653003601050653003601086653003501122653003301157100002001190856006401210       2000                        eng d00aHigh field pulsed terahertz measurements of nonlinear conductivity0 aHigh field pulsed terahertz measurements of nonlinear conductivi  aPostconference  aKaua'i-Lihue, HI, USAc2000  a105 - 1060 v463 a<p>High field pulsed terahertz spectroscopy is used to measure the inplane nonlinear conductivity response of two dimensional electron gases. Results are compared to FEL measurements suggesting LO phonon bottleneck weakening at 0.5 THz.</p>10a0.5 THz10a2D electron gases10aConductivity measurement10aelectrical conductivity measurement10aElectron emission10aFEL measurements10aFinite impulse response filter10ahigh field pulsed terahertz measurements10ahigh field pulsed terahertz spectroscopy10ahigh-speed optical techniques10ainplane nonlinear conductivity response10aLO phonon bottleneck weakening10anonlinear conductivity10anonlinear optics10aphonons10aPower measurement10aPulse measurements10aResonance10asemiconductor quantum wells10aspectroscopy10aSubmillimeter wave measurements10asubmillimetre wave spectroscopy10atwo dimensional electron gases10atwo-dimensional electron gas1 aMarkelz, A., G.  uhttps://ieeexplore.ieee.org/document/883591/authors#authors