Polyhydrazide-Based Organic Nanotubes as Efficient and Selective Artificial Iodide Channels

Reported herein is a series of pore-containing polymeric nanotubes based on a hydrogen-bonded hydrazide backbone. Nanotubes of suitable lengths, possessing a hollow cavity of about a 6.5 Å diameter, mediate highly efficient transport of diverse types of anions, rather than cations, across lipid membranes. The reported polymer channel, having an average molecular weight of 18.2 kDa and 3.6 nm in helical height, exhibits the highest anion-transport activities for iodide (EC₅₀=0.042 μm or 0.028 mol % relative to lipid), whcih is transported 10 times more efficiently than chlorides (EC₅₀=0.47 μm ). Notably, even in cholesterol-rich environment, iodide transport activity remains high with an EC₅₀ of 0.37 μm . Molecular dynamics simulation studies confirm that the channel is highly selective for anions and that such anion selectivity arises from a positive electrostatic potential of the central lumen rendered by the interior-pointing methyl groups.     

Adaptive stabilized interferometer with laser diode

We describe a diode laser interferometer with an electronic adaptive system of fringe pattern stabilization and vibrations suppression. The interferometer allows to obtain up to four high-quality images with relative phase shifts. Also an algorithm for fringe pattern processing has been proposed.     

A regularized point cloud registration approach for orthogonal transformations

An important part of the well-known iterative closest point algorithm (ICP) is the variational problem. Several variants of the variational problem are known, such as point-to-point, point-to-plane, generalized ICP, and normal ICP (NICP). This paper proposes a closed-form exact solution for orthogonal registration of point clouds based on the generalized point-to-point ICP algorithm. We use points and normal vectors to align 3D point clouds, while the common point-to-point approach uses only the coordinates of points. The paper also presents a closed-form approximate solution to the variational problem of the NICP. In addition, the paper introduces a regularization approach and proposes reliable algorithms for solving variational problems using closed-form solutions. The performance of the algorithms is compared with that of common algorithms for solving variational problems of the ICP algorithm. The proposed paper is significantly extended version of Makovetskii et al. (CCIS 1090, 217–231, 2019).

     

Estimation of uncertainty in electrochemical amperometric measurement of dissolved oxygen concentration

A procedure for the estimation of measurement uncertainty of dissolved oxygen (DO) concentration measurement based on the ISO approach is presented. It is based on a mathematical model that involves 14 input parameters. The uncertainty of DO concentration strongly depends on changes in experimental details (temperature difference between calibration and measurement, the time interval between calibration and measurement, etc.). The relative measurement uncertainty is, however, practically independent of the DO concentration itself. The uncertainty is the lowest if the calibration and the measurement are done at the same temperature and on the same day. A calculation tool is provided (in the form of a GUM Workbench file) for practitioners that can be used for uncertainty calculation of DO concentrations at very different experimental conditions.Electronic Supplementary Material The uncertainty calculation example is available as a GUM Workbench calculation file C_O2_meas.smu (GUM Workbench ver. 1.3.3, Metrodata GmbH) together with its data file Input_values.xls (MS Excel 97). For those users who do not have GUM Workbench, the full report of the GUM Workbench calculation is available as a PDF file C_O2_meas.pdf. This material is available via the Internet at .     

Desilylative nitration of C,N‐disilylated 3‐amino‐4‐methylfurazan

3,4‐Bis(3‐nitrofurazan‐4‐yl)furoxanhas been synthesized bynitration of C,N‐bis(trimethylsilyl)derivative of 3‐amino‐4‐methylfurazan with nitrogenoxides.     

Straightforward one-pot synthesis of benzofuroxans from o-halonitrobenzenes in ionic liquids

Treatment of o-halonitrobenzenes with sodium azide in a [empyrr][BF4]/Bu4NBr/H2O system gives benzofuroxans in high yields, with the recovery and reuse of the ionic liquid for at least ten times.