Theory of collision-induced translation-rotation spectra: H2-He

This is the published version, also available here: http://dx.doi.org/10.1103/PhysRevA.29.595.An adiabatic quantal theory of spectral line shapes in collision-induced absorption and emission is presented which incorporates the induced translation-rotation and translation-vibration spectra. The generalization to account for the anisotropy of the scattering potential is given. Calculations are carried out of the collision-induced absorption spectra of He in collisions with H2 with ab initio electric dipole functions and realistic potentials. The anisotropy of the interaction potential is small and is not included in the calculations. The predicted spectra are in satisfactory agreement with experimental data though some deviations occur which may be significant. The rotational line shapes have exponential wings and are not Lorentzian. The connection between the quantal and classical theories is written out explicitly for the isotropic overlap induction

Virtual reality environments for health professional education (Protocol)

Objectives: To assess the effects of virtual reality environment (VRE)-based educational interventions for health professionals on knowledge, skills, and participants’ attitude towards and satisfaction with the interventions. Additionally, this review will assess the interventions' economic impact (cost and cost effectiveness), patient-related outcomes and unintended adverse effects of VRE-based educational interventions for post-registration healthcare providers

Photoelectron Flux Build-Up in the Plasmasphere

Processes which confine photoelectrons to the plasmasphere (e.g., collisional backscattering from the thermosphere and magnetic trapping due to pitch angle redistribution through Coulomb collisions in the plasmasphere) tend to increase the steady state photoelectron flux in the plasmasphere above the amplitude level that would otherwise have been attained. Theoretical calculations are presented of steady state photoelectron fluxes in the plasmasphere, for specified atmospheric and ionospheric conditions. (Observational plasma line intensity data for these conditions exist and will be compared elsewhere.) General features of the angular distribution are presented and compared with observations. The transparency of the plasmasphere and the backscattering properties of the thermosphere are investigated. The buildup effect due to collisional backscatter alone is calculated, and the combined buildup effect of pitch angle diffusion and backscatter is estimated. It is found that the inclusion of these effects increases the steady state photoelectron flux amplitude in the plasmasphere by about 50% over the value obtained when the buildup effects are neglected. The calculated steady state photoelectron fluxes in the plasmasphere are in good agreement with the available observations

Nickel(II) and iron(II) triple helicates assembled from expanded quaterpyridines incorporating flexible linkages

In the present study the interaction of Fe(II) and Ni(II) with the related expanded quaterpyridines, 1,2-, 1,3- and 1,4-bis-(5'-methyl-[2,2']bipyridinyl-5-ylmethoxy)benzene ligands (4–6 respectively), incorporating flexible, bis-aryl/methylene ether linkages in the bridges between the dipyridyl domains, was shown to predominantly result in the assembly of [M2L3]4+ complexes; although with 4 and 6 there was also evidence for the (minor) formation of the corresponding [M4L6]8+ species. Overall, this result contrasts with the behaviour of the essentially rigid 'parent' quaterpyridine 1 for which only tetrahedral [M4L6]8+ cage species were observed when reacted with various Fe(II) salts. It also contrasts with that observed for 2 and 3 incorporating essentially rigid substituted phenylene and biphenylene bridges between the dipyridyl domains where reaction with Fe(II) and Ni(II) yielded both [M2L3]4+ and [M4L6]8+ complex types, but in this case it was the latter species that was assigned as the thermodynamically favoured product type. The X-ray structures of the triple helicate complexes [H2O⊂Ni2(4)3](PF6)4·THF·.2H2O, [Ni2(6)3](PF6)4·195MeCN·1.THF·1.82O, and the very unusual triple helicate PF6− inclusion complex, [(PF6)⊂Ni2(5)3](PF6)3·1.75eCN·5.25TF·0.25H2O are reported

Real-time probing of β-amyloid self-assembly and inhibition using fluorescence self-quenching between neighbouring dyes

The fluorescence response of the Thioflavin-T (ThT) dye and derivatives has become the standard tool for detecting β-amyloid aggregates (Aβ) in solution. However, it is accepted that ThT-based methods suffer from important drawbacks. Some of these are due to the cationic structure of ThT, which limits its application at slightly acidic conditions; whereas some limitations are related to the general use of an extrinsic-dye sensing strategy and its intrinsic requirement for the formation of a sensor-binding site during the aggregation process. Here, we introduce fluorescence-self-quenching (FSQ) between N-terminally tagged peptides as a strategy to overcome some of these limitations. Using a combination of steady-state, picosecond time-resolved fluorescence and transmission electron microscopy, we characterize the fluorescence response of HiLyte fluor 555-labelled Aβ peptides and demonstrate that Aβ self-assembly organizes the covalently attached probes in close proximity to trigger the self-quenching sensing process over a broad range of conditions. Importantly, we prove that N-terminal tagging of β-amyloid peptides does not alter the self-assembly kinetics or the resulting aggregated structures. We also tested the ability of FSQ-based methods to monitor the inhibition of Aβ1–42 aggregation using the small heat-shock protein Hsp20 as a model system. Overall, FSQ-based strategies for amyloid-sensing fill the gap between current morphology-specific protocols using extrinsic dyes, and highly-specialized single-molecule techniques that are difficult to implement in high-throughput analytical determinations. When performed in Förster resonance energy transfer (FRET) format, the method becomes a ratiometric platform to gain insights into amyloid structure and for standardizing in vitro studies of amyloid aggregation