Triangle Percolation in Mean Field Random Graphs—with PDE

We apply a PDE-based method to deduce the critical time and the size of the giant component of the “triangle percolation” on the Erdős-Rényi random graph process investigated by Derényi, Palla and Vicsek in (Phys. Rev. Lett. 94:160202, [2005]; J. Stat. Phys. 128:219–227, [2007]).     

Who's talking first? Consensus or lack thereof in coevolving opinion formation models

We investigate different opinion formation models on adaptive network topologies. Depending on the dynamical process, rewiring can either (i) lead to the elimination of interactions between agents in different states, and accelerate the convergence to a consensus state or break the network in noninteracting groups or (ii), counterintuitively, favor the existence of diverse interacting groups for exponentially long times. The mean-field analysis allows us to elucidate the mechanisms at play. Strikingly, allowing the interacting agents to bear more than one opinion at the same time drastically changes the model's behavior and leads to fast consensus.     

Removal of Water-Soluble Extractives Improves the Enzymatic Digestibility of Steam-Pretreated Softwood Barks

Softwood bark contains a large amounts of extractives—i.e., soluble lipophilic (such as resin acids) and hydrophilic components (phenolic compounds, stilbenes). The effects of the partial removal of water-soluble extractives before acid-catalyzed steam pretreatment on enzymatic digestibility were assessed for two softwood barks—Norway spruce and Scots pine. A simple hot water extraction step removed more than half of the water-soluble extractives from the barks, which improved the enzymatic digestibility of both steam-pretreated materials. This effect was more pronounced for the spruce than the pine bark, as evidenced by the 30 and 11% glucose yield improvement, respectively, in the enzymatic digestibility. Furthermore, analysis of the chemical composition showed that the acid-insoluble lignin content of the pretreated materials decreased when water-soluble extractives were removed prior to steam pretreatment. This can be explained by a decreased formation of water-insoluble “pseudo-lignin” from water-soluble bark phenolics during the acid-catalyzed pretreatment, which otherwise results in distorted lignin analysis and may also contribute to the impaired enzymatic digestibility of the barks. Thus, this study advocates the removal of extractives as the first step in the processing of bark or bark-rich materials in a sugar platform biorefinery.     

Electrically Conductive Composites Based on Chitosan and Graphene Stabilized by Pluronic F-108

Highly concentrated dispersions of few-layer graphene stabilized by amphiphilic block copolymer Pluronic F-108 are obtained. According to transmission electron and atomic force microscopy, the thickness of the graphene particles is on average from one to ten layers and their lateral sizes vary from 150 nm to 1 μm. Using these dispersions, new chitosan-based film composites with the filler content up to 5 wt % are obtained; the electrical conductivity of these composites reaches 4.3 × 10^–1 S/cm.     

Notes on Interpolation. X (Two Boundary Value Problems)

In this paper we use (0, 2) interpolational polynomials to give an approximate solution of the differential equation y(x) + A(x)y(x) = F(x), x I := [-1, 1] j in case when the boundary values are y(-1) = and y(1) = , , R.     

Activation mechanism of the human histamine H4 receptor--an explicit membrane molecular dynamics simulation study

Molecular dynamics (MD) simulations in a membrane-embedded environment were carried out on the homology model of the human histamine H4 receptor (hH4R) alone and in complex with its endogenous activator histamine and with the first reported selective hH4R antagonist JNJ7777120. During the simulation of the histamine-hH4R complex, considerable changes occurred in the hH4R structure as well as in the interaction pattern of histamine at the binding site. These changes are in agreement with experimental data published on GPCR activation. In particular, the intracellular side of TM helix VI moved significantly away from TM helices III and VII. Moreover, histamine formed an interaction with Asn147 (4.57) that was previously proved to be important in hH4R activation. Results of the MD simulations of the native hH4R and the JNJ7777120-hH4R complex suggest that these models represent an inactive conformation of hH4R. MD simulation in the presence of JNJ7777120 resulted in the movement of the intracellular side of TM helix VI in the direction of TM helix III. Snapshots of the simulations may serve as functionally relevant models in the development of novel hH4R ligands in the future.     

RIXS in correlated electron systems under extreme conditions

ABSTRACT

We report here on the application of Resonant Inelastic X-ray Scattering (RIXS) in correlated electrons systems under pressure. Thanks to its bulk sensitivity and superior resolving power, RIXS appears as a powerful spectroscopic technique to unravel the local electronic and magnetic properties of materials at extreme conditions. The method is illustrated in vanadium-oxides- and Fe-based superconductors at high pressure.     

Progress in Polyarsolyl Chemistry

The synthesis of heteroatom analogues of the cyclopentadienyl anion Cp^? is a fascinating and challenging field of research. The replacement of methine moieties by phosphorus is well investigated for the synthesis of mono‐, tri‐ and pentaphospholyl ligands. On the other hand, arsenic derivatives are rare and 1,2,4‐triarsolyl and tetraarsolyl salts are unknown. Herein, we report on the synthesis of Cs[E₃C₂(trip)₂] ( 1 a : E=P; 1 b : E=As; trip=2,4,6‐triisopropylphenyl) and Cs[E₄C(trip)] ( 2 a : E=P; 2 b : E=As). Compound 1 b represents the first 1,2,4‐triarsolyl and 2 b the first tetraarsolyl anion. All salts are obtained in one‐pot syntheses using E(SiMe₃)₃, 2,4,6‐triisopropylbenzoyl chloride and CsF. The products 1 a ?2 C₄H₈O₂, 2 a ?Et₂O and 2 b ?3 C₄H₈O₂ were characterized by X‐ray structural analysis, which revealed planar heterocycles. Nucleus‐independent chemical shifts (NICS) confirmed the aromaticity of these anions. Notably, compound 2 a ?Et₂O is only the second tetraphospholyl ligand which is structurally characterized.     

Fluctuations in the homogenization of semilinear equations with random potentials

We study the stochastic homogenization and obtain a random fluctuation theory for semilinear elliptic equations with a rapidly varying random potential. To first order, the effective potential is the average potential and the nonlinearity is not affected by the randomness. We then study the limiting distribution of the properly scaled homogenization error (random fluctuations) in the space of square integrable functions, and prove that the limit is a Gaussian distribution characterized by homogenized solution, the Green’s function of the linearized equation around the homogenized solution, and by the integral of the correlation function of the random potential. These results enlarge the scope of the framework that we have developed for linear equations to the class of semilinear equations.