Evidence for equilibrium exciton condensation in monolayer WTe2

We present evidence that the two-dimensional bulk of monolayer WTe2 contains electrons and holes bound by Coulomb attraction—excitons—that spontaneously form in thermal equilibrium. On cooling from room temperature to 100 K, the conductivity develops a V-shaped dependence on electrostatic doping, while the chemical potential develops a step at the neutral point. These features are much sharper than is possible in an independent-electron picture, but they can be accounted for if electrons and holes interact strongly and are paired in equilibrium. Our calculations from first principles show that the exciton binding energy is larger than 100 meV and the radius as small as 4 nm, explaining their formation at high temperature and doping levels. Below 100 K, more strongly insulating behaviour is seen, suggesting that a charge-ordered state forms. The observed absence of charge density waves in this state is surprising within an excitonic insulator picture, but we show that it can be explained by the symmetries of the exciton wavefunction. Therefore, in addition to being a topological insulator, monolayer WTe2 exhibits strong correlations over a wide temperature range

Intravenous paracetamol vs ibuprofen in renal colic: a randomised, double-blind, controlled clinical trial

Pain management is one of the essentials of emergency care. Renal colic secondary to urinary stone disease forms one of the most intense pain types. The present study aimed to compare the effect of intravenous ibuprofen to paracetamol in ceasing renal colic. This randomised double-blind study was composed of two intervention arms, intravenous paracetamol and intravenous ibuprofen. Study subjects were randomised to receive a single dose of either paracetamol, 1 g in 100 ml normal saline, or ibuprofen (800 mg in 100 ml normal saline) in a blinded fashion. Subjects reported pain intensity on a visual analogue scale with lines intersection multiples of ten just before the drug administration, 15 and 30 min after the study drug administration. Two hundred patients were randomised to either of two study arms: however, 97 patients in ibuprofen group and 99 patients in paracetamol groups were included into 30 minute analysis. Differences of pain improvements between two groups was 9.5 (5.4–13.7) at 15 min (p = 0.000) and 17.1 (11.9–22.5) at 30 min, those both favouring ibuprofen over paracetamol (p = 0.000). Although ten (10.1%) patients in paracetamol group needed rescue drug, there were only two (2%) patients in ibuprofen group (difference: 8%; 95% CI 0.7–16%, p = 0.02). Intravenous 800 mg ibuprofen is more effective than IV paracetamol in ceasing renal colic at 30 min. © 2017, Springer-Verlag GmbH Germany

Intravenous paracetamol vs ibuprofen in renal colic: a randomised, double-blind, controlled clinical trial.

Pain management is one of the essentials of emergency care. Renal colic secondary to urinary stone disease forms one of the most intense pain types. The present study aimed to compare the effect of intravenous ibuprofen to paracetamol in ceasing renal colic. This randomised double-blind study was composed of two intervention arms, intravenous paracetamol and intravenous ibuprofen. Study subjects were randomised to receive a single dose of either paracetamol, 1 g in 100 ml normal saline, or ibuprofen (800 mg in 100 ml normal saline) in a blinded fashion. Subjects reported pain intensity on a visual analogue scale with lines intersection multiples of ten just before the drug administration, 15 and 30 min after the study drug administration. Two hundred patients were randomised to either of two study arms: however, 97 patients in ibuprofen group and 99 patients in paracetamol groups were included into 30 minute analysis. Differences of pain improvements between two groups was 9.5 (5.4-13.7) at 15 min (p = 0.000) and 17.1 (11.9-22.5) at 30 min, those both favouring ibuprofen over paracetamol (p = 0.000). Although ten (10.1%) patients in paracetamol group needed rescue drug, there were only two (2%) patients in ibuprofen group (difference: 8%; 95% CI 0.7-16%, p = 0.02). Intravenous 800 mg ibuprofen is more effective than IV paracetamol in ceasing renal colic at 30 min

Sensitivity analysis for in-cylinder soot-particle size imaging with laser-induced incandescence

International audienceSoot particle sizes can be determined from time-resolved laser-induced incandescence (LII) in point measurements where full signal traces are detected. For instantaneous imaging, strategies are required that must cope with time-gated information and that rely on assumptions on the local boundary conditions. A model-based analysis is performed to identify the dependence of LII particle-size imaging on the assumed boundary conditions such as bath gas temperature, pressure, particle heat-up temperature, accommodation coefficients, and soot morphology. Various laser-fluence regimes and gas pressures are considered. For 60 bar, fluences that lead to particle heat-up temperatures of 3400– 3900 K provided the lowest sensitivity on particle-sizing. Effects of laser attenuation are evaluated. A combination of one detection gate starting at the signal peak and the other starting with 5 ns delay was found to provide the highest sensitivity at 60 bar. The optimum gate delays for different pressures are shown. The effects of timing jitter and poly-dispersity are investigated. Systematic errors in pyrometry imaging at 60 bar is evaluated

Determination of small soot particles in the presence of large ones from time-resolved laser-induced incandescence

International audienceInformation about the polydispersity of soot can in principle be gained from time-resolved laser-induced incandescence (LII) using pre-assumed particle-size distributions. This paper introduces an alternative method, called two-exponential reverse fitting (TERF) that is based on combined mono-exponential fits to the LII signal decay at various delay times. The method approximates the particle-size distribution as a combination of one large and one small monodisperse equivalent mean particle size and does not require a distribution assumption. It also provides a ratio of the contribution of both size classes. The systematic error caused by describing LII signals by mono-exponential decays is calculated as less than 2% for LII signals simulated for monodisperse aggregated soot with heat-up temperatures for which evaporation is negligible. The effects of particle size, heat-up temperature, aggregate size, and pressure on this error are evaluated. The method is tested on simulated LII signals for lognormal and bimodal size distributions and applied to LII data acquired in a laminar non-premixed ethylene/air flame at various heights above burner. The results are compared to transmission electron microscopy (TEM) measurements of thermophoretically-sampled soot. The particle size of the large particle-size class evaluated with the method showed good consistency with TEM results, however the size of the small particle-size class and the relative contribution could not be compared due to missing information in the TEM results for small particles. These limitations of TEM measurements are discussed and the effect of the exposure time of the sampling grid is evaluated.

Investigations of the long-term effects of LII on soot and bath gas

<p>A combination of high-repetition rate imaging, laser extinction measurements, two-color soot pyrometry imaging, and high-resolution transmission electron microscopy of thermophoretically sampled soot is used to investigate the long-term and permanent effects of rapid heating of in-flame soot during laser-induced incandescence (LII). Experiments are carried out on a laminar non-premixed co-annular ethylene/air flame with various laser fluences. The high-repetition rate images clearly show that the heated and the neighboring laser-border zones undergo a permanent transformation after the laser pulse, and advect vertically with the flow while the permanent marking is preserved. The soot volume fraction at the heated zone reduces due to the sublimation of soot and the subsequent enhanced oxidation. At the laser-border zones, however, optical thickness increases that may be due to thermophoretic forces drawing hot particles towards relatively cooler zones and the rapid compression of the bath gas induced by the pressure waves created by the expansion of the desorbed carbon clusters. Additionally sublimed carbon clusters can condense onto existing particles and contribute to increase of the optical thickness. Time-resolved two-color pyrometry imaging show that the increased temperature of soot both in the heated and neighboring laser-border zones persists for several milliseconds. This can be associated to the increase in the bath-gas temperature, and a change in the wavelength-dependent emissivity of soot particles induced by the thermal annealing of soot. Ex-situ analysis show that the lattice structure of the soot sampled at the laser-border zones tend to change and soot becomes more graphitic. This may be attributed to thermal annealing induced by elevated temperature.</p> <p>Copyright © 2017 American Association for Aerosol Research</p

PEGylated amyloid peptide nanocontainer delivery and release system

A micellar nanocontainer delivery and release system is designed on the basis of a peptide-polymer conjugate. The hybrid molecules self-assemble into micelles comprising a modified amyloid peptide core surrounded by a PEG corona. The modified amyloid peptide previously studied in our group forms helical ribbons based on a beta-sheet motif and contains beta-amino acids that are excluded from the beta-sheet structure, thus being potentially useful as fibrillization inhibitors. In the model peptide-PEG hybrid system studied, enzymatic degradation using alpha-chymotrypsin leads to selective cleavage close to the PEG-peptide linkage, break up of the micelles, and release of peptides in unassociated form. The release of monomeric peptide is useful because aggregation of the released peptide into beta-sheet amyloid fibrils is not observed. This concept has considerable potential in the targeted delivery of peptides for therapeutic applications