For CO 2 sensing studies, chips with multiple NTFET devices were wire bonded and packaged in a 40-pin CERDIP package before functionalization with PEI/starch polymers. The polymer functionalized packaged devices were assembled in a flow cell in which air or CO 2 gas mixtures could be introduced to the devices. The low concentrations of CO 2 were achieved by mixing different proportions of air and 10 % CO 2 in air with a CSSI 1010 precision gas diluter (Custom Sensor Solutions, Inc., Naperville, IL). [8] For some recent examples of solubilization of SWNTs with polymers, see: a) Received

No abstract

We have applied nanoporous anodic alumina films as planar optical waveguides and studied changes in the effective dielectric constants of these thin films due to various processes occurring in the pores. We demonstrate the potential of the porous anodic alumina waveguide for high sensitivity (bio-) chemical sensing with bovine serum albumin adsorption and desorption at various pH values, with subangstrom sensitivity in the effective thickness of protein adsorbed. We also monitored pore widening (alumina dissolution) with subangstrom sensitivity, which is conceptually the reverse of detecting conformal film deposition on pore surfaces. Furthermore, we monitored the exchange of pore-filling media between phosphate buffer solution and ethanol, which produces qualitatively the same response as complete pore filling with other materials by various deposition techniques. Thus porous anodic alumina films may be employed simultaneously as deposition templates and as highly sensitive detectors of processes within the pores.

High density nanoparticle arrays on surfaces have been created using a template‐assisted approach. Templates were produced by evaporating aluminum onto substrates and subsequently anodizing the aluminum to produce nanoporous alumina films. The resulting templates have a narrow distribution of pore sizes tunable from ∼ 25 to ∼ 70 nm. To demonstrate the flexibility of this approach for producing nanoparticle arrays on various substrates, templates have been fabricated on silicon oxide, silicon, and gold surfaces. In all cases, a final chemical etching step yielded pores that extended completely through the template to the underlying substrate. Because the templates remain in intimate contact with the substrate throughout processing, they may be used with either vacuum‐based or wet chemical deposition methods to direct the deposition of nanoparticles onto the underlying substrates. Here we have produced gold nanodot arrays using evaporation and gold nanorod arrays by electrodeposition. In each case, the diameter and height of the nanoparticles can be controlled using the confining dimensions of the templates, resulting in high density (∼ 1010 cm–2) arrays of nanoparticles over large areas (> 1 cm2).

Narrow Bi2Te3 nanowire arrays, where the individual wires are dense and parallel, have been fabricated by electrodeposition. The array–template composites have a high wire density over a large area (see Figure) and are relatively thick, which makes them ideally suited for direct incorporation into existing device structures for thermoelectric or other applications.

Deep learning (DL) neural networks have only recently been employed to interpret chest radiography (CXR) to screen and triage people for pulmonary tuberculosis (TB). No published studies have compared multiple DL systems and populations. We conducted a retrospective evaluation of three DL systems (CAD4TB, Lunit INSIGHT, and qXR) for detecting TB-associated abnormalities in chest radiographs from outpatients in Nepal and Cameroon. All 1196 individuals received a Xpert MTB/RIF assay and a CXR read by two groups of radiologists and the DL systems. Xpert was used as the reference standard. The area under the curve of the three systems was similar: Lunit (0.94, 95% CI: 0.93–0.96), qXR (0.94, 95% CI: 0.92–0.97) and CAD4TB (0.92, 95% CI: 0.90–0.95). When matching the sensitivity of the radiologists, the specificities of the DL systems were significantly higher except for one. Using DL systems to read CXRs could reduce the number of Xpert MTB/RIF tests needed by 66% while maintaining sensitivity at 95% or better. Using a universal cutoff score resulted different performance in each site, highlighting the need to select scores based on the population screened. These DL systems should be considered by TB programs where human resources are constrained, and automated technology is available.

Arrays of bismuth telluride (Bi2Te3) nanowires with diameters of ∼25, ∼50, and ∼75 nm have been produced by electrochemical deposition into porous anodic alumina templates. Scanning electron microscopy confirms that the nanowire arrays are dense with a narrow distribution of nanowire diameters. The structure of the nanowires was assessed immediately after deposition, after annealing to ∼80% of the melting point, and after melting/recrystallization. As determined by XRD analysis, there is strong fiber texture in the arrays that depends on both the nanowire diameter and the postdeposition processing conditions. Bright-field/dark-field imaging and diffraction in the transmission electron microscope reveal that the as-deposited nanowires are polycrystalline with a bamboo-type grain structure that does not change significantly upon annealing, and a similar grain structure is obtained after melting and resolidification.

Mesoporous mixed‐element oxides have proved difficult to synthesize via the surfactant template method that has been applied so successfully to silica. A synthetic strategy based on the use of molecular precursors in conjunction with block copolymer templates is revealed here for the production of homogeneous multi‐component oxides (see Figure).