Fabrication of stable Pd nanowire assisted by hydrogen in solution

We have mechanically fabricated a Pd nanowire in solution under electrochemical potential control. A clear feature appeared in the conductance histogram when the electrochemical potential of the Pd wire was kept at the hydrogen evolution potential. Conductance traces showed the Pd wire was stretched 0.4 nm in length just before breaking, suggesting that at least two Pd atoms might contribute to the formation of the Pd wire. The results indicate that a certain atomic configuration of the Pd nanowire is stabilized by hydrogen. We discuss the stabilization mechanism due to changes in bond strengths caused by hydrogen adsorption or incorporation.Comment: 4 pages, 3 figures, Appl. Phys. Lett., in pres

Prediction of the Size Distributions of Methanol-Ethanol Clusters Detected in VUV Laser/Time-of-flight Mass Spectrometry

The size distributions and geometries of vapor clusters equilibrated with methanol−ethanol (Me−Et) liquid mixtures were recently studied by vacuum ultraviolet (VUV) laser time-of-flight (TOF) mass spectrometry and density functional theory (DFT) calculations (Liu, Y.; Consta, S.; Ogeer, F.; Shi, Y. J.; Lipson, R. H. Can. J. Chem. 2007, 85, 843−852). On the basis of the mass spectra recorded, it was concluded that the formation of neutral tetramers is particularly prominent. Here we develop grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) frameworks to compute cluster size distributions in vapor mixtures that allow a direct comparison with experimental mass spectra. Using the all-atom optimized potential for liquid simulations (OPLS-AA) force field, we systematically examined the neutral cluster size distributions as functions of pressure and temperature. These neutral cluster distributions were then used to derive ionized cluster distributions to compare directly with the experiments. The simulations suggest that supersaturation at 12 to 16 times the equilibrium vapor pressure at 298 K or supercooling at temperature 240 to 260 K at the equilibrium vapor pressure can lead to the relatively abundant tetramer population observed in the experiments. Our simulations capture the most distinct features observed in the experimental TOF mass spectra: Et3H+ at m/z = 139 in the vapor corresponding to 10:90% Me−Et liquid mixture and Me3H+ at m/z = 97 in the vapors corresponding to 50:50% and 90:10% Me−Et liquid mixtures. The hybrid GCMC scheme developed in this work extends the capability of studying the size distributions of neat clusters to mixed species and provides a useful tool for studying environmentally important systems such as atmospheric aerosols

Fundamental Limits of Classical and Quantum Imaging

Quantum imaging promises increased imaging performance over classical protocols. However, there are a number of aspects of quantum imaging that are not well understood. In particular, it has so far been unknown how to compare classical and quantum imaging procedures. Here, we consider classical and quantum imaging in a single theoretical framework and present general fundamental limits on the resolution and the deposition rate for classical and quantum imaging. The resolution can be estimated from the image itself. We present a utility function that allows us to compare imaging protocols in a wide range of applications.Comment: 4 pages, 3 figures; accepted for Physical Review Letters, with updated title and fixed typo

High-Performance Silicon-Based Multiple Wavelength Source

We demonstrate a stable CMOS-compatible on-chip multiple-wavelength source by filtering and modulating individual lines from a frequency comb generated by a microring resonator optical parametric oscillator.. We show comb operation in a low-noise state that is stable and usable for many hours. Bit-error rate measurements demonstrate negligible power penalty from six independent frequencies when compared to a tunable diode laser baseline. Open eye diagrams confirm the fidelity of the 10 Gb/s data transmitted at the comb frequencies and the suitability of this device for use as a fully integrated silicon-based WDM source.Comment: 3 pages, 3 figure

Reflective Synergy: A Research Model for Collaborative Inquiry

A theoretical model for collaborative inquiry as a research methodology in adult education is presented in this paper. The authors discuss the elements of the model along with their lived experience through its development

Single-inhaler fluticasone furoate/umeclidinium/vilanterol versus fluticasone furoate/vilanterol plus umeclidinium using two inhalers for chronic obstructive pulmonary disease: A randomized non-inferiority study

Background: Single-inhaler fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) 100/62.5/25 μg has been shown to improve lung function and health status, and reduce exacerbations, versus budesonide/formoterol in patients with chronic obstructive pulmonary disease (COPD). We evaluated the non-inferiority of single-inhaler FF/UMEC/VI versus FF/VI + UMEC using two inhalers. Methods: Eligible patients with COPD (aged ≥40 years; ≥1 moderate/severe exacerbation in the 12 months before screening) were randomized (1:1; stratified by the number of long-acting bronchodilators [0, 1 or 2] per day during run-in) to receive 24-week FF/UMEC/VI 100/62.5/25 μg and placebo or FF/VI 100/25 μg + UMEC 62.5 μg; all treatments/placebo were delivered using the ELLIPTA inhaler once-daily in the morning. Primary endpoint: change from baseline in trough forced expiratory volume in 1 s (FEV1) at Week 24. The non-inferiority margin for the lower 95% confidence limit was set at − 50 mL. Results: A total of 1055 patients (844 [80%] of whom were enrolled on combination maintenance therapy) were randomized to receive FF/UMEC/VI (n = 527) or FF/VI + UMEC (n = 528). Mean change from baseline in trough FEV1 at Week 24 was 113 mL (95% CI 91, 135) for FF/UMEC/VI and 95 mL (95% CI 72, 117) for FF/VI + UMEC; the between-treatment difference of 18 mL (95% CI -13, 50) confirmed FF/UMEC/VI’s was considered non-inferior to FF/ VI + UMEC. At Week 24, the proportion of responders based on St George’s Respiratory Questionnaire Total score was 50% (FF/UMEC/VI) and 51% (FF/VI + UMEC); the proportion of responders based on the Transitional Dyspnea Index focal score was similar (56% both groups). A similar proportion of patients experienced a moderate/severe exacerbation in the FF/UMEC/VI (24%) and FF/VI + UMEC (27%) groups; the hazard ratio for time to first moderate/ severe exacerbation with FF/UMEC/VI versus FF/VI + UMEC was 0.87 (95% CI 0.68, 1.12). The incidence of adverse events was comparable in both groups (48%); the incidence of serious adverse events was 10% (FF/UMEC/VI) and 11% (FF/VI + UMEC). Conclusions: Single-inhaler triple therapy (FF/UMEC/VI) is non-inferior to two inhalers (FF/VI + UMEC) on trough FEV1 change from baseline at 24 weeks. Results were similar on all other measures of efficacy, health-related quality of life, and safety. Trial registration: GSK study CTT200812; ClinicalTrials.gov NCT02729051 (submitted 31 March 2016)

Unleashing the Artist Within: New Directions for Research in Adult Education

The potential for using various art forms (drama, poetry, music, literature, visual art) in the collection and analysis of data, and in the expression of research findings is explored in this roundtable discussion