Cellular SERS structures for non-invasive study of living cells

Surface-enhanced Raman spectroscopy (SERS) is a potent and highly selective tool to chemically identify and determine the structure of molecules and materials. However, the large biomolecules and living cells are still difficult to study using modern SERS-substrates. Here we present a new approach to the geometry of the surface of plasmon nanostructures (cellular surfaces), which makes it possible to efficiently work with volumetric objects as cells or organelles. We use the scanning Raman microscope to map the SERS from the specially prepared microcapsules formed with a Layer-by-Layer deposition method and with built-in Raman tags (Indocyanine green). It demonstrated the possibility to detect SERS signal from Indocyanine green in microcapsules located in cavities, while the signal from the Raman dye in microcapsules located on a flat surface is not detected. The obtained results can be useful in biosensors applications.

Fast Computation by MLFMM-FFT with NURBS in Large Volumetric Dielectric Structures

A refinement for the computation of the rigorous part of the multi-level fast multipole method (MLFMM) of analyzing volumetric objects is presented. A scheme based on the fast Fourier technique (FFT) is proposed with the objective of reducing the computational resources required to accurately analyze large homogeneous and non-homogeneous dielectric volumes. In order to reduce the memory requirements, the storage of the near-field terms of the method of moments (MoM) matrix is performed only for the positions corresponding to a parallelepiped with the size of the level 1 block of the MLFMM, computed with the vacuum permittivity, taking advantage of the Toeplitz symmetry present in regular hexahedral meshes. The FFT avoids applying the near-field MoM matrix in the iterative solution process. The application of this approach results in huge improvements in terms of memory usage, but also a speeds up the iterative solution process because the use of three-dimensional (3D) FFTs is very efficient for computing convolutions when the number of unknowns of the problems becomes very large as happens in volumetric problems. We also propose a new approach for the numerical treatment of the transition of the dielectric permittivity between different dielectrics or between a dielectric and a free space. To validate the computation technique, the radar cross section (RCS) of several dielectric bodies is computed using the classical MLFMM approach and it is compared with the presented FFT-based-MLFMM solution. The results demonstrate that the efficient memory and computation time usage of the proposed approach.

Methods For Calculating Radio Holograms Of Volumetric Objects

A method for calculating holograms for volumetric objects based on the representation of objects in the form of ensembles of virtual point sources distributed on a set of parallel planes has been proposed. The proposed method is the development of the well-known method in which objects are represented as ensemble of real point scatterers. The possibilities of the proposed method are demonstrated by calculating a hologram of a fragment of a sphere, on which 1000 points are randomly selected, at which radiation emanating from the center of the sphere is scattered. The choice of a fragment of a sphere as an object under study is due to the fact that when calculating its hologram, phase errors inherent in approximate calculations are most pronounced. The calculations were performed for the frequency range of 2...100 GHz, the sphere radius of 0.5 m, a two-dimensional hologram size of 0.65×0.65 m, and a pixel count of 512×512. It is shown that, in comparison with the known method, the proposed method makes it possible to calculate the amplitude of a hologram with satisfactory accuracy if virtual sources are placed on parallel planes in an amount of more than 64 pieces. In the case of objects that require representation in the form of an ensemble of point scatterers in the amount of more than 1000 pieces, the calculation of their holograms by the proposed method turns out to be much more efficient than the known method.

DIVA: natural navigation inside 3D images using virtual reality

As three-dimensional microscopy becomes commonplace in biological re-search, there is an increasing need for researchers to be able to view experimental image stacks in a natural three-dimensional viewing context. Through stereoscopy and motion tracking, commercial virtual reality headsets provide a solution to this important visualization challenge by allowing researchers to view volumetric objects in an entirely intuitive fashion. With this motivation, we present DIVA, a user-friendly software tool that automatically creates detailed three-dimensional reconstructions of raw experimental image stacks that are integrated in virtual reality. In DIVA’s immersive virtual environment, users can view, manipulate and perform volumetric measurements on their microscopy images as they would to real physical objects. In contrast to similar solutions, our software provides high-quality volume rendering with native TIFF file compatibility. We benchmark the software with diverse image types including those generated by confocal, light-sheet and electron microscopy. DIVA is available at https://diva.pasteur.fr and will be regularly updated.

Casting

This chapter investigates how projection mapping reconfigures the relationship between projection surface, moving image, and space in the field of artists’ projected moving-image works. Projection mapping is a relatively new method that can be used to transform irregularly shaped objects and indoor/outdoor spaces into display surfaces. This mode of projection envelops three-dimensional surfaces with digital moving images, using complicated projection technologies. In examining this process, the author analyses various contextual reviews as well as her own piece Casting to discover projection mapping’s distinctive properties. Casting (2016) is Kang’s projection-mapping installation at the Victoria and Albert Museum (V&A) in London, which was created as the culmination of Kang’s six-month artist-in-residency program at the V&A, and acquired by the institution in 2017 as its first purchase of a projection-mapping installation piece. This chapter examines how, by integrating volumetric objects and space, projection mapping dismantles the conventional notion of screen and frame that are accepted in experimental film and video installation works. The chapter introduces the concept of augmented space to understand how the spatial employment of projected moving images generates a novel type of narrative and experiences in comparison with the previous projected moving-image artworks. Accordingly, the chapter identifies how projection mapping practices can develop a distinguished type of aura in the realm of digital media art works.

POSSIBILITIES OF APPLYING MACHINE VISION TO INCREASE EFFICIENCY OF FUNCTIONING OF A GRAIN-CLEANING MACHINE

The article provides a rationale for the use of machine vision systems on grain cleaning machines. The paper presents the dependence of the purity of the grain material, the content of weed and grain impurities, the loss of grain material relative to the feed in kg / s. In addition, the article provides an overview of the most used systems for detecting volumetric objects, and histograms of the most significant characteristics of the systems under consideration are constructed.

Real-Time Augmented Reality Physics Simulator for Education

Physics education applications using augmented reality technology, which has been developed extensively in recent years, have a lot of restrictions in terms of performance and accuracy. The purpose of our research is to develop a real-time simulation system for physics education that is based on parallel processing. In this paper, we present a video see-through AR (Augmented Reality) system that includes an environment recognizer using a depth image of Microsoft’s Kinect V2 and a real-time soft body simulator based on parallel processing using GPU (Graphic Processing Unit). Soft body simulation can provide more realistic simulation results than rigid body simulation, so it can be more effective in systems for physics education. We have designed and implemented a system that provides the physical deformation and movement of 3D volumetric objects, and uses them in education. To verify the usefulness of the proposed system, we conducted a questionnaire survey of 10 students majoring in physics education. As a result of the questionnaire survey, 93% of respondents answered that they would like to use it for education. We plan to use the stand-alone AR device including one or more cameras to improve the system in the future.

APPLICATION OF LASER PHOTONICS METHODS IN ORTHOPEDIC DENTISTRY FOR NON-INVASIVE NON-CONTACT EXAMINATION OF BULK MICRO-DEFORMATIONS OF BONE TISSUE

Modern methods of laser photonics, which make it possible to measure the dynamics of micro-deformations of volumetric objects without contact and with high sensitivity, find increasing application in a wide variety of fields. Particularly attractive is the use of such a delicate, non-perturbing technique in medicine. The article reports on experiments using laser photonics methods in dental implantology, which allowed to give practical medical recommendations. In the work, a study was made of the possibilities of holographic and speckle interferometry methods for measuring the deformation of the jaw bone tissue with a step-by-step installation of cylindrical and conical mini implants. The possibility of determining the relaxation time of deformations after the installation of mini implants was demonstrated. The purpose of this work is to justify the possibility and feasibility of using laser photonics to solve this medical problem.

Visual Awareness and Visual Appearances

Many philosophers from the traditions of both phenomenology and analytic philosophy have observed that our perceptual (e.g. visual) experience involves a certain duality. In the terminology used in this chapter, we seem to be visually aware of more than what is visually apparent to us. Such duality is present in various cases, from the perception of opaque volumetric objects to that of natural kinds, artefacts, and familiar persons. This chapter offers a general account of the duality, according to which visual appearances supervene on low-level visual facts while the scope of visual awareness depends on context-sensitive cognitive habits or heuristics based on visual appearances.

MODELLING ABOVE GROUND BIOMASS OF MANGROVE FOREST USING SENTINEL-1 IMAGERY

Many studies have been conducted in the estimation of forest above ground biomass (AGB) using features from synthetic aperture radar (SAR). Specifically, L-band ALOS/PALSAR (wavelength ~23&amp;thinsp;cm) data is often used. However, few studies have been made on the use of shorter wavelengths (e.g., C-band, 3.75&amp;thinsp;cm to 7.5&amp;thinsp;cm) for forest mapping especially in tropical forests since higher attenuation is observed for volumetric objects where energy propagated is absorbed. This study aims to model AGB estimates of mangrove forest using information derived from Sentinel-1 C-band SAR data. Combinations of polarisations (VV, VH), its derivatives, grey level co-occurrence matrix (GLCM), and its principal components were used as features for modelling AGB. Five models were tested with varying combinations of features; a) sigma nought polarisations and its derivatives; b) GLCM textures; c) the first five principal components; d) combination of models a&amp;minus;c; and e) the identified important features by Random Forest variable importance algorithm. Random Forest was used as regressor to compute for the AGB estimates to avoid over fitting caused by the introduction of too many features in the model. Model e obtained the highest r² of 0.79 and an RMSE of 0.44&amp;thinsp;Mg using only four features, namely, &amp;sigma;^&amp;deg;_<i>VH</i> GLCM variance, &amp;sigma;^&amp;deg;_<i>VH</i> GLCM contrast, PC1, and PC2. This study shows that Sentinel-1 C-band SAR data could be used to produce acceptable AGB estimates in mangrove forest to compensate for the unavailability of longer wavelength SAR.