Rapid Development of a Tool for Prioritizing Patients with Coronavirus Disease 2019 for Intensive Care.

Objectives: To explain and demonstrate a new approach for rapidly developing a decision-support tool for prioritizing patients with coronovirus 2019 disease for admission to ICUs.

Design: An expert group used multi-criteria decision analysis methods to specify criteria and weights, representing their relative importance, for prioritizing patients with coronovirus 2019 disease with respect to likely clinical benefit. Specialized multi-criteria decision analysis software, implementing the "Potentially All Pairwise RanKings of all possible Alternatives" method to determine the weights, was used.

Lamplight Stabilization for GPS Rb Atomic Clocks via RF-Power Control.

Recent evidence indicates that the signal-in-space user-range-error (SIS-URE) for GPS is strongly influenced by the satellite atomic clock's rubidium (Rb) lamplight intensity jumps. Following a proposal by Bloom and Bell, we have implemented RF-power control of an RF-discharge lamp of the type employed in Rb atomic frequency standards (RAFS). Since Rb lamplight intensity jumps are mapped onto the clock's output frequency via the light-shift effect, stabilization of the Rb light emitted by the lamp has the potential to significantly improve the RAFS' long-term frequency stability, and hence the GPS SIS-URE.

Carbon nanotube modified probes for stable and high sensitivity conductive atomic force microscopy.

Conductive atomic force microscopy (C-AFM) is used to characterise the nanoscale electrical properties of many conducting and semiconducting materials. We investigate the effect of single walled carbon nanotube (SWCNT) modification of commercial Pt/Ir cantilevers on the sensitivity and image stability during C-AFM imaging. Pt/Ir cantilevers were modified with small bundles of SWCNTs via a manual attachment procedure and secured with a conductive platinum pad.

Accurate thickness measurement of graphene.

Graphene has emerged as a material with a vast variety of applications. The electronic, optical and mechanical properties of graphene are strongly influenced by the number of layers present in a sample. As a result, the dimensional characterization of graphene films is crucial, especially with the continued development of new synthesis methods and applications.

Planar silver nanowire, carbon nanotube and PEDOT:PSS nanocomposite transparent electrodes.

Highly conductive, transparent and flexible planar electrodes were fabricated using interwoven silver nanowires and single-walled carbon nanotubes (AgNW:SWCNT) in a PEDOT:PSS matrix via an epoxy transfer method from a silicon template. The planar electrodes achieved a sheet resistance of 6.6 ± 0.

Highly conductive interwoven carbon nanotube and silver nanowire transparent electrodes.

Electrodes fabricated using commercially available silver nanowires (AgNWs) and single walled carbon nanotubes (SWCNTs) produced sheet resistances in the range 4-24 Ω □ with specular transparencies up to 82 %. Increasing the aqueous dispersibility of SWCNTs decreased the bundle size present in the film resulting in improved SWCNT surface dispersion in the films without compromising transparency or sheet resistance. In addition to providing conduction pathways between the AgNW network, the SWCNTs also provide structural support, creating stable self-supporting films.

Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales.

Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures.

Transition metal-substituted Dawson anions as chemo- and regio-selective oxygen transfer catalysts for H2O2 in the epoxidation of allylic alcohols.

Organic-soluble transition metal-substituted Dawson compounds [(n-C(4)H(9))(4)N](9)[P(2)W(17)O(61)M(Br)] (M(n+) = Co(2+), Ni(2+), Cu(2+) and Zn(2+)), [(n-C(4)H(9))(4)N](7)[HP(2)W(17)O(61)M(Br)] (M(n+) = Cr(3+), Mn(3+) and Fe(3+)) and [K/(n-C(4)H(9))(4)N](10-n)[P(2)W(17)O(61)M(H(2)O)] (M(n+) = Ir(4+), Ru(3+) and Pd(2+)) have been investigated as oxygen transfer agents for H(2)O(2) to a series of primary allylic alcohols to generate epoxides under biphasic reaction conditions (1,2-dichloroethane/H(2)O) at 30 or 35 degrees C, such that the effect of variations in the substituted transition metals could be evaluated. The allylic alcohols involved the species R(1)R(2)C=C(R(3))CH(2)-OH (where R(1), R(2) and R(3) = H or Me), as well as cyclic (2-cyclohexen-1-ol), bicyclic [(R-)-(-)-myrtenol and (R-)-(-)-nopol] and species with two unsaturated sites (geraniol and nerol). The reactions are highly chemoselective and regioselective.

Analysis and demonstration of coupling control in polymer microring resonators using photobleaching.

We describe postfabrication trimming of coupling in both laterally and vertically coupled polymer microring resonators (MRRs), using photobleaching. For both cases, a tapered directional-coupler-based simple analytical model is developed to simulate the change in coupling due to a bleaching-induced decrease in refractive index. A tightly focused laser beam spot (a few kilowatts per square centimeter) is used to precisely bleach the coupling region alone.

Grating-assisted coupling of optical fibers and photonic crystal waveguides.

We propose and analyze a highly efficient method of coupling light from optical fibers to two-dimensional photonic crystal waveguides. Efficient coupling is achieved by positioning of a tapered fiber parallel to the linear defect, where the photonic crystal's cladding functions as a grating coupler and provides field confinement as well. Numerical simulations indicate that better than 90% transmission is possible with a full width at half-magnitude bandwidth of 12nm.

Calculated out-of-plane transmission loss for photonic-crystal slab waveguides.

A fully three-dimensional finite-difference time domain numerical model is presented for calculating the out-of-plane radiation loss in photonic-crystal slab waveguides. The propagation loss of a single-line defect waveguide in triangular-lattice photonic crystals is calculated for suspended-membrane, oxidized-lower-cladding, and deeply etched structures. The results show that low-loss waveguides are achievable for sufficiently suspended membranes and oxidized-lower-cladding structures.