Lindberg Vistisen (thrilldinner9)

The kinetics analysis proved the necessity for incorporating into kinetics modeling not only the static properties of reaction minima and transition states but more importantly, the kinetics of individual base-pair conformers that have formed in collisional activation. The analysis also pinpointed the origin of the statistical kinetics of HG-[9MG·1MC + H]+vs. the non-statistical behavior of WC-[9MG·1MC + H]+ in terms of their distinctively different intra-base-pair hydrogen-bonds and consequently the absence of proton transfer between the N1 position of 9MG and the N3' of 1MC in the Hoogsteen base pair. Finally, the Hoogsteen base pair was examined in the presence of a water ligand, i.e., HG-[9MG·1MC + H]+·H2O. Besides the same type of base-pair dissociation as detected in dry HG-[9MG·1MC + H]+, secondary methanol elimination was observed via the SN2 reaction of water with nucleobase methyl groups.We study how crowding affects the activity and catalysis-enhanced diffusion of enzymes and passive tracers by employing a fluctuating-dumbbell model of conformation-changing enzymes. Our Brownian dynamics simulations reveal that the diffusion of enzymes depends qualitatively on the type of crowding. If only enzymes are present in the system, the catalysis-induced enhancement of the enzyme diffusion - somewhat counter-intuitively - increases with crowding, while it decreases if crowding is due to inert particles. For the tracers, the diffusion enhancement increases with increasing the enzyme concentration. We also show how the enzyme activity is reduced by crowding and propose a simple expression to describe this reduction. Our results highlight subtle effects at play concerning enzymatic activity and macromolecular transport in crowded systems, such as, e.g., the interior of living cells.The vibrational spectrum of liquid and solid nitroethane was measured as a function of pressure. Both Raman scattering and absorption IR spectroscopies were applied to samples of nitroethane, statically compressed at ambient temperature to a maximum pressure of 8.0 GPa and 16.9 GPa, respectively. A new amorphous to crystalline transition pressure was found to lie between 1.59-1.63 GPa. Davydov splitting of internal modes into two components suggests two molecules associated with the unit cell, which is consistent with the DFT predictions made in a previous study. For most bands below 1200 cm-1, pressure induced mode progression was consistent with DFT predictions. Conversely, observed mode shifts in the 2950-3100 cm-1 region were generally stiffer than their DFT counterparts. A discontinuity in mode evolution between 3.7-4.3 GPa was observed for a number of modes and shown to coincide with hydrogen bond rearrangement in this pressure region. Preferred orientation and crystallite strain might explain the increased scatter between the various pressure induced mode shift cycles. Time intervals on the order of ∼30 h may be required between spectra, in order to give the crystallites time to equilibrate their strain.Limonene with endo- and exo-double bonds is a significant monoterpene in the atmosphere and has high reactivity towards O3. see more We investigated the atmospheric oxidation mechanism of limonene ozonolysis using a high level quantum chemistry calculation coupled with RRKM-ME kinetic simulation. The additions of O3 can take place at both the endo- and exo-double bonds with a branching ratio of 0.87 0.13, forming four major highly energized CIs* (named Syn-2a*, Syn-2b*, Anti-2b* and Anti-2c*) with the relative higher fractions of 0.21 0.35 0.27 0.11. A yield of 4% for Limona-ketone was obtained as well. For the unimolecular isomerization pathways of limonene + O3 → POZs → CIs* → SOZ, VHP, or dioxirane, five, one, or none of the internal rotations are treated as hindered internal rotors for CIs*. We obtained percentages of 0.59 0.18 0.14 in total for separate isomerization routes in the formation of VHPs, dioxirane and SOZs from CIs* u