Notes

Methylene orange adsorption in thermo plasma tv's broadened graphite in the multilayer ray system.
The outstanding performance of NiOOH/FeOOH-based oxygen evolution reaction (OER) catalysts is rationalized in terms of a bifunctional mechanism involving two distinct active sites. In this mechanism, the OOHads reaction intermediate, which unfavorably affects the overall OER activity due to the linear scaling relationship, is replaced by O2 adsorbed at the active site on FeOOH and Hads adsorbed at the NiOOH substrate. Here, we use the computational hydrogen electrode method to assess promising models of both the FeOOH catalyst and the NiOOH hydrogen acceptor. These two materials are interfaced in various ways to evaluate their performance as bifunctional OER catalysts. In some cases, overpotentials as low as 0.16 V are found, supporting the bifunctional mechanism as a means to overcome the limitations imposed by linear scaling relationships.Vacuum ultraviolet (VUV) light at 118 nm has been shown to be a powerful tool to ionize molecules for various gas-phase chemical studies. A convenient table top source of 118 nm light can be produced by frequency tripling 355 nm light from a NdYAG laser in xenon gas. This process has a low efficiency, typically producing only nJ/pulse of VUV light. Simple models of the tripling process predict that the power of 118 nm light produced should increase quadratically with increasing xenon pressure. However, experimental 118 nm production has been observed to reach a maximum and then decrease to zero with increasing xenon pressure. Here, we describe the basic theory and experimental setup for producing 118 nm light and a new proposed model for the mechanism limiting the production based on pressure broadened absorption.Thermodiffusion in liquids (the Soret effect) has several unusual properties. In particular, transport can occur with or against a temperature gradient depending on the case. Numerous empirical correlations have been proposed with mixed success or range of applicability. Here, we show that physicochemical mechanics, derived from the Smoluchowski equation as a description of diffusive transport phenomena, is in accord with the experimental and simulated thermodiffusion data from colloidal beads and biomacromolecules to ionic solutions and ultracold fluid mixtures. It yields a simple formula for the Soret coefficient ST based on the reference molar entropy including non-ideality. Hydrodynamic and local non-equilibrium effects are discussed but not included as these are apparently not a major contribution for the wide range of solutes under the near-equilibrium experimental conditions considered here.In a previous work [Pan et al., Molecules 23, 2500 (2018)], a charge projection scheme was reported, where outer molecular mechanical (MM) charges [>10 Å from the quantum mechanical (QM) region] were projected onto the electrostatic potential (ESP) grid of the QM region to accurately and efficiently capture long-range electrostatics in ab initio QM/MM calculations. Here, a further simplification to the model is proposed, where the outer MM charges are projected onto inner MM atom positions (instead of ESP grid positions). This enables a representation of the long-range MM electrostatic potential via augmentary charges (AC) on inner MM atoms. Combined with the long-range electrostatic correction function from Cisneros et al. [J. Chem. Phys. 143, 044103 (2015)] to smoothly switch between inner and outer MM regions, this new QM/MM-AC electrostatic model yields accurate and continuous ab initio QM/MM electrostatic energies with a 10 Å cutoff between inner and outer MM regions. This model enables efficient QM/MM cluster calculations with a large number of MM atoms as well as QM/MM calculations with periodic boundary conditions.The p53 transcription factor is a key mediator in cellular responses to various stress signals including DNA repair, cell cycle arrest, and apoptosis. In this work, we employ landscape and flux theory to investigate underlying mechanisms of p53-regulated cell fate decisions. Based on a p53 regulatory network, we quantified the potential landscape and probabilistic flux for the p53 system. The landscape topography unifies and quantifies three cell fate states, including the limit cycle oscillations (representing cell cycle arrest), high p53 state (characterizing apoptosis), and low p53 state (characterizing the normal proliferative state). Landscape and flux results provide a quantitative explanation for the biphasic dynamics of the p53 system. In the oscillatory phase (first phase), the landscape attracts the system into the ring valley and flux drives the system cyclically moving, leading to cell cycle arrest. In the fate decision-making phase (second phase), the ring valley shape of the landscape provides an efficient way for cells to return to the normal proliferative state once DNA damage is repaired. If the damage is unrepairable with larger flux, the system may cross the barrier between two states and switch to the apoptotic state with a high p53 level. By landscape-flux decomposition, we revealed a trade-off between stability (guaranteed by landscape) and function (driven by flux) in cellular systems. Cells need to keep a balance between appropriate speed to repair DNA damage and appropriate stability to survive. This is further supported by flux landscape analysis showing that flux may provide the dynamical origin of phase transition in a non-equilibrium system by changing landscape topography.Exchange and correlation holes are unique quantum concepts for understanding the nature of electron interactions based on quantum conditional probabilities. Among those, the exact exchange hole is of special interest since it is derived rigorously from first principles without approximations and is often modeled by approximate exchange expressions of density functional theory. In this work, the algorithm for the computation of the spherically averaged exact exchange hole for a given reference point is developed and implemented for molecular orbitals in Gaussian basis functions. The formulas include a novel recursive relation for the spherical average of the Bessel function of the first kind and the asymptotic expressions when the exponential factor of the Bessel function becomes large. MEK inhibitor This new capability is used to explore the extent to which current popular model exchange holes resemble or differ from the exact exchange hole. Point-wise accuracy of the exchange holes for isolated atoms is important in local hybrid schemes, real-space models of static correlation, and others.
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