Tyrosine nitration of human ERK1 introduces an intra-hydrogen bond by molecular dynamics simulations

Structural Chemistry - ERK1 is an important kinase in Ras–Raf–MEK signaling. We have recently demonstrated by mass spectrometry that Tyr210 of ERK1 can be nitrated, and the nitration...     

Steady state hot atom kinetic theory model calculations. Time dependent rate coefficients for the nonthermal 18F + H2 reaction

This paper briefly summarizes the methodology and results for a new type of hot atom kinetic theory model calculation. The microscopic time dependence for the nuclear recoil ¹⁸F + H₂ reaction is characterized using the steady state kinetic theory of hot atom reactions. The relaxing hot atom laboratory momentum distribution is represented using a local equilibrium model. The calculated results illustrate the nature and significance of quasi steady state reaction rate coefficients and of the dynamical coupling between reactive heating and nonreactive cooling phenomena. Under nuclear recoil conditions the nonthermal ¹⁸F + H₂ reaction, which exhibits a total hot yield of 100%, fails to establish a high temperature steady state.     

Localized magnon gap modes in the 2-d Ising antiferromagnets K2CoF4 and Rb2CoF4

The defect (Mn²⁺,Ni²⁺,Fe²⁺) induced magnon gap modes in the layered antiferromagnets K₂CoF₄ and Rb₂CoF₄ were investigated with the methods of FIR absorption-and IR emission spectroscopy. The anisotropic exchange-parameters describing the strongly localized Mn²⁺ spin excitations far below the host lattice magnon band and the Ni²⁺ excitations in the vacinity of this band are presented. In the diluted system K₂Co_1-cMn_cF₄ localized Mn²⁺ cluster modes up to about C≈0.1 were observed. The excitation energy of these modes can only be explained by assuming an anisotropic Mn²⁺-Mn²⁺ exchange which is in contrast to the pure isomorphous system K₂MnF₄. In the spin mismatch system K₂CoF₄: Fe the magnetic moments of the isolated Fe²⁺ impurities are pulled from the plane perpendicular to the c-axis and aligned parallel to the easy axis of the magnetic crystal.     

CW infrared laseraction of optically pumped Co2+:KZnF3

The optical properties of KZnF₃:Co²⁺ were investigated by means of absorption and emission spectroscopy in the visible and infrared spectral region. This system is suitable for laseraction between the lowest ⁴T₁(⁴F)-⁴T₂(⁴F) Co²⁺ phonon sidebands. CW laseraction of more than 20 mW (85K) was observed at 1.95 μm when pumped with an Ar⁺-laser at 514 μm (1.5W). The system is at least tunable between 2.05 μm to 1.85 μm.     

F-to-HF reactions. VIII. Nonthermal complications for the CHF3/C3F6/C2F6 moderated nuclear recoil system

Results are reported from moderated nuclear recoil ¹⁸F experiments with the 273 K CHF₃/C₃F₆/C₂F₆ system. Although the measurement sensitivity is only about ±12%, there is no evidence to support the occurrence of nonthermal F-to-HF reactions at 95 mol % C₂F₆ moderator concentration.