Singular value decomposition for the 2D fan-beam Radon transform of tensor fields

In this article we study the fan-beam Radon transform ${\cal D}_m$ of symmetrical solenoidal 2D tensor fields of arbitrary rank $m$ in a unit disc $\mathbb D$ as the operator, acting from the object space ${\mathbf L}_{2}(\mathbb D; {\bf S}_m)$ to the data space $L_2([0,2\pi)\times[0,2\pi)).$ The orthogonal polynomial basis ${\bf s}^{(\pm m)}_{n,k}$ of solenoidal tensor fields on the disc $\mathbb D$ was built with the help of Zernike polynomials and then a singular value decomposition (SVD) for the operator ${\cal D}_m$ was obtained. The inversion formula for the fan-beam tensor transform ${\cal D}_m$ follows from this decomposition. Thus obtained inversion formula can be used as a tomographic filter for splitting a known tensor field into potential and solenoidal parts. Numerical results are presented.Comment: LaTeX, 37 pages with 5 figure

A REVIEW OF ANCISTRONYCHA M¾RKEL WITH THE DESCRIPTION OF ATALANTYCHA, A NEW NEARCTIC GENUS (COLEOPTERA: CANTHARIDAE)

Abstract The genus Ancistronycha Märkel is reviewed. Atalantycha, new genus, is described

Dynamic image recognition in a spiking neuron network supplied by astrocytes

Mathematical model of spiking neuron network (SNN) supplied by astrocytes is investigated. The astrocytes are specific type of brain cells which are not electrically excitable but inducing chemical modulations of neuronal firing. We analyzed how the astrocytes influence on images encoded in the form of dynamic spiking pattern of the SNN. Serving at much slower time scale the astrocytic network interacting with the spiking neurons can remarkably enhance the image recognition quality. Spiking dynamics was affected by noise distorting the information image. We demonstrated that the activation of astrocyte can significantly suppress noise influence improving dynamic image representation by the SNN.Comment: arXiv admin note: text overlap with arXiv:2210.0101

Nanomaterials Potentiating Standard Chemotherapy Drugs' Effect

Application of antitumor chemotherapeutic drugs is hindered by a number of barriers, multidrug resistance that makes effective drug deposition inside cancer cells difficult is among them. Recent research shows that potential efficiency of anticancer drugs can be increased with nanoparticles. This review is devoted to the application of nanoparticles for cancer treatment. Various types of nanoparticles currently used in medicine are reviewed. The nanoparticles that have been used for cancer therapy and targeted drug delivery to damaged sites of organism are described. Also, the possibility of nanoparticles application for cancer diagnosis that could help early detection of tumors is discussed. Our investigations of antitumor activity of low-dimensional nanostructures based on aluminum oxides and hydroxides are briefly reviewed

A New Lycid Genus from the Dominican Amber (Insecta, Coleoptera, Lycidae, Leptolycinae, Leptolycini)

A new fossil genus, Electropteron  gen.n., and a new species, E. avus  sp.n., are described from the Dominican Amber. Electropteron avus  gen.n., sp.n., appears to be related to some of the extant Great Antillean lycids and is the first fossil taxon from the subfamily Leptolycinae

Zeta potential change of Neuro-2a tumor cells after exposure to alumina nanoparticles

In recent years, researches have paid much attention to the physical, chemical, biophysical and biochemical properties of a cell surface. It is known that most of the cells’ surfaces are charged. This charge depends on the biochemical structure of the cell membranes. Therefore, measurement of a cell surface charge is a significant criterion that gives information about the cell surface. Evaluation of the cells zeta-potential is important to understand the interaction mechanisms of various drugs, antibiotics, as well as the interaction of nanoparticles with the cell surface. In this study, we use the dynamic light scattering method to detect the zeta-potential change of Neuro-2a tumor cells. It has been observed that zeta-potential shifted to negative values after exposure to metal oxide nanoparticles and inducing apoptosis

Astrocyte control bursting mode of spiking neuron network with memristor-implemented plasticity

A mathematical model of a spiking neuron network accompanied by astrocytes is considered. The network is composed of excitatory and inhibitory neurons with synaptic connections supplied by a memristor-based model of plasticity. Another mechanism for changing the synaptic connections involves astrocytic regulations using the concept of tripartite synapses. In the absence of memristor-based plasticity, the connections between these neurons drive the network dynamics into a burst mode, as observed in many experimental neurobiological studies when investigating living networks in neuronal cultures. The memristive plasticity implementing synaptic plasticity in inhibitory synapses results in a shift in network dynamics towards an asynchronous mode. Next,it is found that accounting for astrocytic regulation in glutamatergic excitatory synapses enable the restoration of 'normal' burst dynamics. The conditions and parameters of such astrocytic regulation's impact on burst dynamics established