Global behavior of cosmological dynamics with interacting Veneziano ghost

In this paper, we shall study the dynamical behavior of the universe accelerated by the so called Veneziano ghost dark energy component locally and globally by using the linearization and nullcline method developed in this paper. The energy density is generalized to be proportional to the Hawking temperature defined on the trapping horizon instead of Hubble horizon of the Friedmann-Robertson-Walker (FRW) universe. We also give a prediction of the fate of the universe and present the bifurcation phenomenon of the dynamical system of the universe. It seems that the universe could be dominated by dark energy at present in some region of the parameter space.Comment: 8 pages, 7 figures, accepted for publication in JHE

Effective Activation of Strong C−Cl Bonds for Highly Selective Photosynthesis of Bibenzyl via Homo-Coupling

Carbon-carbon (C−C) coupling of organic halides has been successfully achieved in homogeneous catalysis, while the limitation, e.g., the dependence on rare noble metals, complexity of the metal-ligand catalylst and the poor catalyst stability and recyclability, needs to be tackled for a green process. The past few years have witnessed heterogeneous photocatalysis as a green and novel method for organic synthesis processes. However, the study on C−C coupling of chloride substrates is rare due to the extremely high bond energy of C−Cl bond (327 kJ mol−1). Here, we report a robust heterogeneous photocatalyst (Cu/ZnO) to drive the homo-coupling of benzyl chloride with high efficiency, which achieves an unprecedented high selectivity of bibenzyl (93 %) and yield rate of 92 % at room temperature. Moreover, this photocatalytic process has been validated for C−C coupling of 10 benzylic chlorides all with high yields. In addition, the excellent stability has been observed for 8 cycles of reactions. With detailed characterization and DFT calculation, the high selectivity is attributed to the enhanced adsorption of reactants, stabilization of intermediates (benzyl radicals) for the selective coupling by the Cu loading and the moderate oxidation ability of the ZnO support, besides the promoted charge separation and transfer by Cu species

Synergy of Ag and AgBr in a Pressurized Flow Reactor for Selective Photocatalytic Oxidative Coupling of Methane

Oxidation of methane into valuable chemicals, such as C2+ molecules, has been long sought after but the dilemma between high yield and high selectivity of desired products remains. Herein, methane is upgraded through the photocatalytic oxidative coupling of methane (OCM) over a ternary Ag-AgBr/TiO2 catalyst in a pressurized flow reactor. The ethane yield of 35.4 μmol/h with a high C2+ selectivity of 79% has been obtained under 6 bar pressure. These are much better than most of the previous benchmark performance in photocatalytic OCM processes. These results are attributed to the synergy between Ag and AgBr, where Ag serves as an electron acceptor and promotes the charge transfer and AgBr forms a heterostructure with TiO2 not only to facilitate charge separation but also to avoid the overoxidation process. This work thus demonstrates an efficient strategy for photocatalytic methane conversion by both the rational design of the catalyst for the high selectivity and reactor engineering for the high conversion

Selective catalytic oxidation of ammonia over nano Cu/zeolites with different topologies

The selective catalytic oxidation of ammonia (NH3-SCO) is the last mitigation step in exhaust treatment using a 4-way catalytic converter to convert any excess and unreacted NH3 (that was used as a reductant of NOx) into environmentally benign N2 and H2O. Here, we report a series of highly reactive and selective nano Cu/zeolites for the NH3-SCO reaction. The NH3-SCO activity was found in the order nano Cu/ZSM-5 (MFI topology) > Cu/Beta (BEA) > Cu/MCM-49 (MWW) > Cu/Y (FAU) > Cu/Mordenite (MOR) > Cu/Ferrierite (FER). The best catalyst, i.e., nano Cu/ZSM-5, achieves 98% NH3 conversion at 250 °C with the N2 yield maintained at >98% even at up to 500 °C. When assessed under practical exhaust conditions in the presence of moisture (5% H2O) as well as that after hydrothermal aging (5% H2O, 850 °C, 8 h), the nano Cu/ZSM-5 exhibited only minor deactivation as a result of its good retention of Cu dispersion, pore structure and specific surface area. Furthermore, small micropore (10-membered ring, 10-MR) topologies were found to be crucial in maintaining high N2 yields. For Cu/Y and Cu/Mordenite, composed of 12-MR pores that are non-interconnected with smaller pores, their N2 yields were compromised by forming NOx at temperatures above 400 °C. Based on the in situ DRIFTS study, the iSCR mechanism appears to be applicable for all fresh and aged Cu/zeolites with the exception of fresh Cu/MCM-49 that follows the imide mechanism

Versatile Preparation of Mesoporous Single-Layered Transition-Metal Sulfide/Carbon Composites for Enhanced Sodium Storage

Transition metal sulfides are promise electrochemical energy storage materials due to their abundant active sites, large inter-layer space and high theoretical capacities. Especially for sodium storage. However, the low conductivity and poor cycling stability at high current densities hampered their applications. Herein, we report a versatile dual-templates method to elaborate ordered mesoporous single layered MoS2 /carbon composite with high specific area, uniform pore size and large pore volume. The single layered MoS2 is confined in the carbon matrix. The mesopores between the composite nanorods provide fast electrolyte diffusion. The obtained nanocomposite shows a high sodium storage capability, excellent rate capacity, and very good cycling performance. A 310 mAh g-1 capacity can remains at 5.0 A g-1 after 2500 cycles. Furthermore, a SIB full cell composed the MoS2 /carbon composite anode and a Na3 V2 (PO4 )3 (NVP) cathode maintains a specific capacity of 330 mA h g-1 at 1.0 A g-1 during 100 cycles. The mechanism is investigated by in situ and ex situ characterizations as well as density functional theory (DFT) calculations. This article is protected by copyright. All rights reserved

Advanced Li₂S/Si Full Battery Enabled by TiN Polysulfide Immobilizer

Lithium sulfide (Li2S) is a promising cathode material with high capacity, which can be paired with nonlithium metal anodes such as silicon or tin so that the safety issues caused by the Li anode can be effectively avoided. However, the Li2S full cell suffers from rapid capacity degradation due to the dissolution of intermediate polysulfides. Herein, a Li2S/Si full cell is designed with a Li2S cathode incorporated by titanium nitride (TiN) polysulfide immobilizer within parallel hollow carbon (PHC). This full cell delivers a high initial reversible capacity of 702 mAh gLi2S−1 (1007 mAh gsulfur−1) at 0.5 C rate and excellent cyclability with only 0.4% capacity fade per cycle over 200 cycles. The long cycle stability is ascribed to the strong polysulfide anchor effect of TiN and highly efficient electron/ion transport within the interconnected web‐like architecture of PHC. Theoretical calculations, self‐discharge measurements, and anode stability experiments further confirm the strong adsorption of polysulfides on the TiN surface. The present work demonstrates that the flexible Li2S cathode and paired Si anode can be used to achieve highly efficient Li‐S full cells

Collagen characteristics affect the texture of pork Longissimus and Biceps femoris

Connective tissue is considered to infuence the toughness of pork, but most studies on connective tissue focus on the loin muscle. Cooking loss, Warner–Bratzler shear force (WBSF), texture profle analysis (hardness, springiness, chewiness, resilience, and cohesiveness), total and insoluble collagen content, the percentage of type III collagen relative to the total of type I and III collagen, proteoglycan content and intramuscular fat (IMF) content were measured for pork Biceps femoris (BF) and Longissimus thoracis et lumborum (LTL) and Pearson’s correlation was performed. The results showed that BF had higher WBSF, resilience, total, and insoluble collagen content than LTL (P < 0.05). When considering both muscles, total and insoluble collagen content were positively correlated (P < 0.05) with WBSF (r = 0.47 and 0.49, respectively), hardness (r = 0.49 and 0.50, respectively), cohesiveness (r = 0.50 and 0.50, respectively), chewiness (r = 0.58 and 0.59, respectively) and resilience (r = 0.63 and 0.63, respectively). The percentage of type III collagen content was negatively correlated (P < 0.05) with WBSF (r = −0.68) and hardness (r = −0.58). Collagen content was correlated (P < 0.05) with WBSF (r = 0.75) and hardness (r = 0.61) in LTL and with cohesiveness (r = 0.74) and resilience (r = 0.63) in BF. Collagen characteristics differ between muscles and contribute to pork texture in both LTL and BF

Conserved Genetic Interactions between Ciliopathy Complexes Cooperatively Support Ciliogenesis and Ciliary Signaling

Mutations in genes encoding cilia proteins cause human ciliopathies, diverse disorders affecting many tissues. Individual genes can be linked to ciliopathies with dramatically different phenotypes, suggesting that genetic modifiers may participate in their pathogenesis. The ciliary transition zone contains two protein complexes affected in the ciliopathies Meckel syndrome (MKS) and nephronophthisis (NPHP). The BBSome is a third protein complex, affected in the ciliopathy Bardet-Biedl syndrome (BBS). We tested whether mutations in MKS, NPHP and BBS complex genes modify the phenotypic consequences of one another in both C. elegans and mice. To this end, we identified TCTN-1, the C. elegans ortholog of vertebrate MKS complex components called Tectonics, as an evolutionarily conserved transition zone protein. Neither disruption of TCTN-1 alone or together with MKS complex components abrogated ciliary structure in C. elegans. In contrast, disruption of TCTN-1 together with either of two NPHP complex components, NPHP-1 or NPHP-4, compromised ciliary structure. Similarly, disruption of an NPHP complex component and the BBS complex component BBS-5 individually did not compromise ciliary structure, but together did. As in nematodes, disrupting two components of the mouse MKS complex did not cause additive phenotypes compared to single mutants. However, disrupting both Tctn1 and either Nphp1 or Nphp4 exacerbated defects in ciliogenesis and cilia-associated developmental signaling, as did disrupting both Tctn1 and the BBSome component Bbs1. Thus, we demonstrate that ciliary complexes act in parallel to support ciliary function and suggest that human ciliopathy phenotypes are altered by genetic interactions between different ciliary biochemical complexes

TVL₁ Planarity Regularization for 3D Shape Approximation

The modern emergence of automation in many industries has given impetus to extensive research into mobile robotics. Novel perception technologies now enable cars to drive autonomously, tractors to till a field automatically and underwater robots to construct pipelines. An essential requirement to facilitate both perception and autonomous navigation is the analysis of the 3D environment using sensors like laser scanners or stereo cameras. 3D sensors generate a very large number of 3D data points when sampling object shapes within an environment, but crucially do not provide any intrinsic information about the environment which the robots operate within. This work focuses on the fundamental task of 3D shape reconstruction and modelling from 3D point clouds. The novelty lies in the representation of surfaces by algebraic functions having limited support, which enables the extraction of smooth consistent implicit shapes from noisy samples with a heterogeneous density. The minimization of total variation of second differential degree makes it possible to enforce planar surfaces which often occur in man-made environments. Applying the new technique means that less accurate, low-cost 3D sensors can be employed without sacrificing the 3D shape reconstruction accuracy