Cut-free Calculi and Relational Semantics for Temporal STIT Logics

We present cut-free labelled sequent calculi for a central formalism in logics of agency: STIT logics with temporal operators. These include sequent systems for Ldm , Tstit and Xstit. All calculi presented possess essential structural properties such as contraction- and cut-admissibility. The labelled calculi G3Ldm and G3Tstit are shown sound and complete relative to irreflexive temporal frames. Additionally, we extend current results by showing that also Xstit can be characterized through relational frames, omitting the use of BT+AC frames

Novel Computational Simulation of Redox Reactions Within a Metal Electrospray Emitter

To further both our fundamental understanding implications of the electrolytic nature of the electrospray and our understanding of the analytical ion source, in the context of electrospray mass spectrometry (ES-MS), a computational simulation of the oxidation of chemical species inside a metal emitter has been developed. The analysis code employs a boundary integral method for the solution of the Laplace equation for the electric potential and current, and incorporates standard activation and concentration polarization functions for the redox active species in the system to define the boundary conditions. The specific system modeled consisted of a 100 {mu}m i .d., inert metal capillary CHICN/H2O (90/10 V/V). ES emitter and a spray solution comprised of an analyte dissolved in Variable parameters included the concentration (i.e., 5, 10, 20, and 50 ~M) of the easily oxidized analyte ferrocene (Fe, dicyclopentadienyl iron) in the solution, and solution conductivities of 1.9, 3.8, and 7.6 x 107 Mho/cm. ES currents were on the order of 0.05 {mu}A and the flow rate was 5 @A_nin. Under these defined conditions, the two most prominent reactions at the emitter metakolution interface were assumed to be H20 oxidation (2H20 = 02 + 4H+ + 4e") and Fe oxidation (Fe = Fe' +e-). Using this model it was possible to predict the inter-facial potentials, as well as the current density for each of the reactions, as a function of axial position from the emitter spray tip back upstream, under the various operational conditions. Computational fluid dynamics (CFD) calculations showed that the imposed flow rate through the emitter was adequate to prevent significant back-diffusion of Fe+ into the emitter against the flow direction. The computational simulations predict the same behavior for the ES ion source as has been observed experimentally and is consistent with the controlled-current electrolytic cell analogy of Van Berkel and Zhou (Anal. Chem. 1995, 67,.2916-2923). Furthermore, the simulations demonstrate that the majority of the current involved in the redox reactions originated within a 200- 300 ~m region near the spray tip

Multi-machine benchmark of the self-consistent 1D scrape-off layer model DIV1D from stagnation point to target with SOLPS-ITER

This paper extends a 1D dynamic physics-based model of the scrape-off layer (SOL) plasma, DIV1D, to include the core SOL and possibly a second target. The extended model is benchmarked on 1D mapped SOLPS-ITER simulations to find input settings for DIV1D that allow it to describe SOL plasmas from upstream to target—calibrating it on a scenario and device basis. The benchmark shows a quantitative match between DIV1D and 1D mapped SOLPS-ITER profiles for the heat flux, electron temperature, and electron density within roughly 50% on: (1) the Tokamak Configuration Variable (TCV) for a gas puff scan; (2) a single SOLPS-ITER simulation of the Upgraded Mega Ampere Spherical Tokamak; and (3) the Upgraded Axially Symmetric Divertor EXperiment in Garching Tokamak (AUG) for a simultaneous scan in heating power and gas puff. Once calibrated, DIV1D self-consistently describes dependencies of the SOL solution on core fluxes and external neutral gas densities for a density scan on TCV whereas a varying SOL width is used in DIV1D for AUG to match a simultaneous change in power and density. The ability to calibrate DIV1D on a scenario and device basis is enabled by accounting for cross field transport with an effective flux expansion factor and by allowing neutrals to be exchanged between SOL and adjacent domains.</p

Structural basis of metallo-β-lactamase, serine-β-lactamase and penicillin-binding protein inhibition by cyclic boronates

β-Lactamases enable resistance to almost all β-lactam antibiotics. Pioneering work revealed that acyclic boronic acids can act as ‘transition state analogue’ inhibitors of nucleophilic serine enzymes, including serine-β-lactamases. Here we report biochemical and biophysical analyses revealing that cyclic boronates potently inhibit both nucleophilic serine and zinc-dependent β-lactamases by a mechanism involving mimicking of the common tetrahedral intermediate. Cyclic boronates also potently inhibit the non-essential penicillin-binding protein PBP 5 by the same mechanism of action. The results open the way for development of dual action inhibitors effective against both serine- and metallo-β-lactamases, and which could also have antimicrobial activity through inhibition of PBPs

Stabilization of mesoporous nanocrystalline zirconia with Laponite

The mesoporous nanocrystalline zircoina was synthesized via solid state reaction-structure directing method in the presence of Laponite. The introduction of Laponite renders the higher thermal stability and lamellar track to the zirconia. Laponite acts as inhibitor for crystal growth and also hard template for the mesostructure. The role of Laponite is attributed to the interaction between the zirconia precursors and the nano-platelets of Laponite via the bridge of hydrophilic segments of surfactant. It results in the formation of Zr-O-Mg-O-Si frameworks in the direction of Laponite layer with the condensation of frameworks during the calcination process, which contributes the higher stability and lamellar structure to the nano-sized zirconia samples