Abstract: To gain insight into the nature of the adhesion mechanism between hydroxyapatite (HA) and rutile (rTiO(2)), the mutual affinity between their surfaces was systematically studied using density functional theory (DFT). We calculated both bulk and surface properties of HA and rTiO(2), and explored the interfacial bonding mechanism of amorphous HA (aHA) surface onto amorphous as well as stoichiometric and nonstoichiometric crystalline rTiO(2). Formation energies of bridging and subbridging oxygen vacancies considered in the rTiO(2)(110) surface were evaluated and compared with other theoretical and experimental results. The interfacial interaction was evaluated through the work of adhesion. For the aHA/rTiO(2)(110) interfaces, the work of adhesion is found to depend strongly on the chemical environment of the rTiO(2)(110) surface. Electronic analysis indicates that the charge transfer is very small in the case of interface formation between aHA and crystalline rTiO(2)(110). In contrast, significant charge transfer occurs between aHA and amorphous rTiO(2) (aTiO(2)) slabs during the formation of the interface. Charge density difference (CDD) analysis indicates that the dominant interactions in the interface have significant covalent character, and in particular the Ti-O and Ca-O bonds. Thus, the obtained results reveal that the aHA/aTiO(2) interface shows a more preferable interaction and is thermodynamically more stable than other interfaces. These results are particularly important for improving the long-term stability of HA-based implants.

Abstract: Quantized magnetic vortices driven by electric current determine key electromagnetic properties of superconductors. While the dynamic behavior of slow vortices has been thoroughly investigated, the physics of ultrafast vortices under strong currents remains largely unexplored. Here, we use a nanoscale scanning superconducting quantum interference device to image vortices penetrating into a superconducting Pb film at rates of tens of GHz and moving with velocities of up to tens of km/s, which are not only much larger than the speed of sound but also exceed the pair-breaking speed limit of superconducting condensate. These experiments reveal formation of mesoscopic vortex channels which undergo cascades of bifurcations as the current and magnetic field increase. Our numerical simulations predict metamorphosis of fast Abrikosov vortices into mixed Abrikosov-Josephson vortices at even higher velocities. This work offers an insight into the fundamental physics of dynamic vortex states of superconductors at high current densities, crucial for many applications.

Abstract: Molecular dynamics simulations are used to investigate the structural properties of a two-dimensional ensemble of magnetic rods, which are modeled as aligned single dipolar beads. The obtained self-assembled configurations can be characterized as (1) clusters, (2) percolated, and (3) ordered structures, and their structural properties are investigated in detail. By increasing the aspect ratio of the magnetic rods, we show that the percolation transition is suppressed due to the reduced mobility of the rods in two dimensions. Such a behavior is opposite to the one observed in three dimensions. A magnetic bulk phase is found with local ferromagnetic order and an unusual nonmonotonic behavior of the nematic order is observed.

Abstract: The conformational and configurational preferences of Me2PNSNPMe2 (3) and Me2PNSNAsMe2 (4) have been identified using quantum chemical calculations at the DFT/B3LYP/6-311+G* level of theory. An approach in which energetic, structural (geometries and bond orders), electronic (analysis of the electron density) and spectroscopic properties are combined leads to the conclusion that these sulfur-nitrogen-pnictogen chains share many of the properties of their chalcogen-nitrogen analogues but that the through-space intramolecular interactions favouring the Z,Z configuration are even weaker than in these latter compounds. The results of this analysis also lead to an unambiguous assignment of the variable-temperature 31P and 15N NMR spectra of these compounds and their structures both in solution and in the solid state.

Abstract: Recently, Sr-doped LaCrO3 has been experimentally introduced as a new p-type transparent conducting oxide. It is demonstrated that substituting Sr for La results in inducing p-type conductivity in LaCrO3. Performing first principles calculations we study the electronic structure and formation energy of various point defects in LaCrO3. Our results for the formation energies show that in addition to Sr, two more divalent defects, Ca and Ba, substituting for La in LaCrO3, behave as shallow acceptors in line with previous experimental reports. We further demonstrate that under oxygen-poor growth conditions, these shallow acceptors will be compensated by intrinsic donor-like defects (an oxygen vacancy and Cr on an oxygen site), but in the oxygen-rich growth regime the shallow acceptors have the lowest formation energies between all considered defects and will lead to p-type conductivity.

Abstract: Blue-colored molybdenum oxide nitrides of the Mo-2(O,N,square)(5) type were synthesized by direct nitridation of commercially available molybdenum trioxide with a mixture of gaseous ammonia and oxygen. Chemical composition, crystal structure, and stability of the obtained and hitherto unknown compounds are studied extensively. The average oxidation state of +5 for molybdenum is proven by Mo K near-edge X-ray absorption spectroscopy; the magnetic behavior is in agreement with compounds exhibiting (MoO6)-O-v units. The new materials are stable up to similar to 773 K in an inert gas atmosphere. At higher temperatures, decomposition is observed. X-ray and neutron powder diffraction, electron diffraction, and high-resolution transmission electron microscopy reveal the structure to be related to VNb9O24.9-type phases, however, with severe disorder hampering full structure determination. Still, the results demonstrate the possibility of a future synthesis of the potential binary oxide Mo2O5. On the basis of these findings, a tentative suggestion on the crystal structure of the potential compound Mo2O5, backed by electronic-structure and phonon calculations from first principles, is given.

Abstract: Synthetic glucocorticoids (GC) are the mainstay therapy for treatment of acute and chronic inflammatory disorders. Due to the high adverse effects associated with long-term use, GC pharmacology has focused since the nineties on more selective GC ligand-binding strategies, classified as selective glucocorticoid receptor (GR) agonists (SEGRAs) or selective glucocorticoid receptor modulators (SEGRMs). In the current study, GSK866 analogs with electrophilic covalent-binding warheads were developed with potential SEGRA properties to improve their clinical safety profile for long-lasting topical skin disease applications. Since the off-rate of a covalently binding drug is negligible compared to that of a non-covalent drug, its therapeutic effects can be prolonged and typically, smaller doses of the drug are necessary to reach the same level of therapeutic efficacy, thereby potentially reducing systemic side effects. Different analogs of SEGRA GSK866 coupled to cysteine reactive warheads were characterized for GR potency and selectivity in various biochemical and cellular assays. GR- and NFκB-dependent reporter gene studies show favorable anti-inflammatory properties with reduced GR transactivation of two non-steroidal GSK866 analogs UAMC-1217 and UAMC-1218, whereas UAMC-1158 and UAMC-1159 compounds failed to modulate cellular GR activity. These results were further supported by GR immuno-localization and S211 phospho-GR western analysis, illustrating significant GR phosphoactivation and nuclear translocation upon treatment of GSK866, UAMC-1217, or UAMC-1218, but not in case of UAMC-1158 or UAMC-1159. Furthermore, mass spectrometry analysis of tryptic peptides of recombinant GR ligand-binding domain (LBD) bound to UAMC-1217 or UAMC-1218 confirmed covalent cysteine-dependent GR binding. Finally, molecular dynamics simulations, as well as glucocorticoid receptor ligand-binding domain (GR-LBD) coregulator interaction profiling of the GR-LBD bound to GSK866 or its covalently binding analogs UAMC-1217 or UAMC-1218 revealed subtle conformational differences that might underlie their SEGRA properties. Altogether, GSK866 analogs UAMC-1217 and UAMC-1218 hold promise as a novel class of covalent-binding SEGRA ligands for the treatment of topical inflammatory skin disorders.

Abstract: Ablation-controlled plasmas have been used in a range of technical applications where local thermodynamic equilibrium (LTE) is often violated near the wall due to the strong cooling effect caused by the ablation of wall materials. The thermodynamic and transport properties of ablated polytetrafluoroethylene (PTFE) vapor, which determine the flowing plasma behavior in such applications, are calculated based on a two-temperature model at atmospheric pressure. To our knowledge, no data for PTFE have been reported in the literature. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and the Guldberg-Waage equation according to van de Sanden et al's derivation. The transport coefficients, including viscosity, thermal conductivity and electrical conductivity, are calculated with the most recent collision interaction potentials using Devoto's electron and heavy-particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of the Chapman-Enskog method. Results are computed for different degrees of thermal non-equilibrium, i.e. the ratio of electron to heavy-particle temperatures, from 1 to 10, with electron temperature ranging from 300 to 40 000 K. Plasma transport properties in the LTE state obtained from the present work are compared with existing published results and the causes for the discrepancy analyzed. The two-temperature plasma properties calculated in the present work enable the modeling of wall ablation-controlled plasma processes.

Abstract: The dithiol functionalized UiO-66-(SH)(2) is developed as an efficient adsorbent for the removal of mercury in aqueous media. Important parameters for the application of MOFs in real-life circumstances include: stability and recyclability of the adsorbents, selectivity for the targeted Hg species in the presence of much higher concentrations of interfering species, and ability to purify wastewater below international environmental limits within a short time. We show that UiO-66-(SH)(2) meets all these criteria.

Abstract: Phase-junctions. between a cocatalyst and its semiconductor host are quite effective to enhance the photo catalytic activity and are widely studied, while reports on the phase-juncted cocatalyst are still rare. In this work, we report the deposition of the Pt/PtO phase-juncted nanodots as cocatalyst via NaOH modification of an interconnected meso-macroporous TiO2 network with high surface area and inner-particle mesopores to enhance the performance of photocatalytic H-2 production. Our results show that NaOH modification can largely influence Pt/PtO phase-juncted nanodot formation and dispersity. Compared to the TiO2 nano particles, the hierarchically meso-macroporous TiO2 network containing 0.18 wt % Pt/PtO phase-juneted cocatalyst demonstrates a highest photocatalytic H-2 rate of 13 mmol g(-1) h(-1) under simulated solar light, and possesses a stable cycling activity without obvious decrease after five cycles. Such high H-2 production performance can be attributed to both the phase-juncted Pt/PtO providing more active sites while PtO suppresses the undesirable hydrogen back reaction, and the special hierarchically porous TiO2 network with inner-particle mesopores presenting short diffusion path lengths for photogenerated electrons and enhanced light harvesting efficiency. This work suggests that Pt/PtO phase-juncted cocatalyst on hierarchically porous TiO2 nanostructures is a promising strategy for advanced photocatalytic H-2 production.

Abstract: Bilayer graphene can exhibit deformations such that the two graphene sheets are locally detached from each other resulting in a structure consisting of domains with different van der Waals inter-layer coupling. Here we investigate how the presence of these domains affects the transport properties of bilayer graphene. We derive analytical expressions for the transmission probability, and the corresponding conductance, across walls separating different inter-layer coupling domains. We find that the transmission can exhibit a valley-dependent layer asymmetry and that the domain walls have a considerable effect on the chiral tunnelling properties of the charge carriers. We show that transport measurements allow one to obtain the strength with which the two layers are coupled. We perform numerical calculations for systems with two domain walls and find that the availability of multiple transport channels in bilayer graphene significantly modifies the conductance dependence on inter-layer potential asymmetry.