The Approach for Studying Variability of Sea Wave Spectra in a Wide Range of Wavelengths from High-Resolution Satellite Optical Imagery

The development and validation of a method for remote measurement of the spectra of sea waves, which significantly expands the capabilities to study surface waves in large water areas in a wide range of wavelengths, is described. The applied approach is based on the use of retrieving operators, which are constructed by the method of numerical simulation, taking into account the nonlinear nature of brightness field modulation by the slopes of the sea surface. Retrieving operators have a set of parameters that are adapted to the real conditions of aerospace imaging. To assess the adequacy of the retrieving of wave spectra recorded from satellite images, they are compared with the spectra obtained by ground-based means under controlled conditions. The studies have shown the adequacy of remote measurement of the spectra of slopes and elevations of sea waves with wavelengths in the range 0.1–1 m. The possibility of using the developed method for studying the variability of sea waves in the coastal zone under conditions of limited fetch, including in the presence of anthropogenic disturbances, is shown.

Currency paper from waste textile lint fibers: Nanofibrillated cellulose and combined system of starch-nanocellulose and polyacrylamide-nanocellulose substituting for long-fiber chemical pulp

Nanofibrillated cellulose (NFC) and a combined systems of NFC with cationic starch or cationic polyacrylamide were used in place of long-fiber chemical pulp in manufacturing currency paper from waste lint fibers from the textile industry. Handmade papers (60 g) were produced from each treatment, and the physical, mechanical, and optical characteristics of papers were compared. The results showed that increasing amounts of NFC by itself increased tensile strength, resistance to bursting, tearing, porosity, and opacity, and decreased the resistance to folding and brightness. Increasing NFC in combination with cationic starch reduced the need for chemical pulp, while improving porosity, opacity, and brightness and increased tensile strength, bursting strength, resistance to tearing, and folding in comparison to the use of long-fiber pulp. Increasing NFC in combination with cationic polyacrylamide, compared to long-fiber chemical pulp, increased opacity, tensile strength, and resistance to bursting and decreased the porosity, resistance to tearing, folding, and brightness. Field emission-scanning electron microscopy results showed that an enhanced percentage of NFC reduced porosity so that addition of 5% cellulosic nanofiber made the paper surface smoother and pores were relatively filled.

Single particle electron cryomicroscopy: trends, issues and future perspective

There has been enormous progress during the last few years in the determination of three-dimensional biological structures by single particle electron cryomicroscopy (cryoEM), allowing maps to be obtained with higher resolution and from fewer images than required previously. This is due principally to the introduction of a new type of direct electron detector that has 2- to 3-fold higher detective quantum efficiency than available previously, and to the improvement of the computational algorithms for image processing. In spite of the great strides that have been made, quantitative analysis shows that there are still significant gains to be made provided that the problems associated with image degradation can be solved, possibly by minimising beam-induced specimen movement and charge build up during imaging. If this can be achieved, it should be possible to obtain near atomic resolution structures of smaller single particles, using fewer images and resolving more conformational states than at present, thus realising the full potential of the method. The recent popularity of cryoEM for molecular structure determination also highlights the need for lower cost microscopes, so we encourage development of an inexpensive, 100 keV electron cryomicroscope with a high-brightness field emission gun to make the method accessible to individual groups or institutions that cannot afford the investment and running costs of a state-of-the-art 300 keV installation. A key requisite for successful high-resolution structure determination by cryoEM includes interpretation of images and optimising the biochemistry and grid preparation to obtain nicely distributed macromolecules of interest. We thus include in this review a gallery of cryoEM micrographs that shows illustrative examples of single particle images of large and small macromolecular complexes.