30 results match your criteria: "St. Petersburg State Electrotechnical University[Affiliation]"

Article Synopsis
  • Strontium-barium niobate (SrBaNbO) films are promising for microwave applications due to their high dielectric nonlinearity and low losses.
  • The films were synthesized on sapphire substrates using magnetron sputtering, and their structural features were analyzed through various methods, focusing on Brillouin light scattering.
  • Brillouin light scattering proved to be an effective nondestructive technique for examining the films' structures, allowing precise determination of their thickness and unique properties influenced by acoustic wave scattering.
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Comparison of passive targeted delivery of inorganic and organic nanocarriers among different types of tumors.

Nanomedicine

July 2024

Laboratory of Nano- and Microencapsulation of Biologically Active Substances, Peter The Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St. Petersburg 195251, Russia. Electronic address:

In this study, we have considered four types of nanoparticles (NPs): polylactic acid (PLA), gold (Au), calcium carbonate (CaCO), and silica (SiO) with similar sizes (TEM: 50-110 nm and DLS: 110-140 nm) to examine their passive accumulation in three different tumors: colon (CT26), melanoma (B16-F10), and breast (4T1) cancers. Our results demonstrate that each tumor model showed a different accumulation of NPs, in the following order: CT26 > B16-F10 > 4T1. The Au and PLA NPs were evidently characterized by a higher delivery efficiency in case of CT26 tumors compared to CaCO and SiO NPs.

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AlF has interesting electrophysical properties, due to which the material is promising for applications in supercapacitors, UV coatings with low refractive index, excimer laser mirrors, and photolithography. The formation of AlF-based nano- and micro-wires can bring new functionalities to AlF material. AlF nanowires are used, for example, in functionally modified microprobes for a scanning probe microscope.

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Light-trapping structures formed on surfaces of various materials have attracted much attention in recent years due to their important role in many applications of science and technology. This article discusses various methods for manufacturing light-trapping "black" silicon, namely laser, chemical and hybrid chemical/laser ones. In addition to the widely explored laser texturing and chemical etching methods, we develop a hybrid chemical/laser texturing method, consisting in laser post-texturing of pyramidal structures obtained after chemical etching.

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Determination of respiratory rate is a necessary task in assessing the state of health in humans. This review provides a description of modern devices used for recording and monitoring respiratory rate. The advantages and disadvantages of the principles of operation of these devices are discussed.

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Due to the COVID-19 epidemic, the challenge of introducing methods for investigating patients reducing or eliminating the probability of infection of medical staff is currently relevant. This article provides an analytical review of new technological approaches to organizing the work of medical personnel in carrying out auscultation of patients with COVID-19. The development and approval of such technologies is shown to have started around the world.

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For the purposes of this work, children with disabilities include disabled children or children aged 0 to 8 years who are not recognized as disabled in the prescribed manner, but who have temporary or permanent deviations in physical and (or) mental development (hereinafter - children with disabilities). The legislative basis for the implementation of the rights and opportunities of children with disabilities and their families is constituted by constitutional provisions that enshrine state guarantees for the protection of childhood, motherhood, paternity, family (part 1 of article 38, paragraph "g.1" of part 1 of article 72 of the Constitution of the Russian Federation).

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The surface properties of zinc oxide powders prepared using mechanical activation, electron beam irradiation, and vacuum annealing, as well using combinations of these types of treatments, were studied using X-ray photoelectron spectroscopy. The structure of the obtained materials was studied by an X-ray diffraction technique and by scanning electron microscopy. We found that over five hours of grinding in an attritor, the size of nanocrystals decreases from 37 to 21 nm, and microdeformations increase from 0.

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The Canonical Table of the Genetic Code as a periodic system of triplets.

Biosystems

April 2022

St. Petersburg State Electrotechnical University, Prof. Popov str. 5, 197376, St. Petersburg, Russia. Electronic address:

The Canonical Table of the Genetic Code (CTGC) is constructed theoretically on the basis of the similarity of PFs (PF) of proteins with the conformation of 4-arc chain graphs (Karasev, 2019). Of the 64 conformations of the graph, specified by the position of the connectivity edges, and the matrices of 6 variables (x … x), x = (0, 1), 4 blocks of 16 elements each were formed. Then they were coded in the form of triplets based on the correspondence of pairs of variables to four letters of the code: 00 = C, 01 = U, 10 = G, 11 = A, and supplemented based on the known triplet-amino acid assignment.

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Researchers working in various domains are focusing on extracting information from data sets by data mining techniques. However, data mining is a complicated task, including multiple complex processes, so that it is unfriendly to non-computer researchers. Due to the lack of experience, they cannot design suitable workflows that lead to satisfactory results.

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This article addresses the monitoring problem of the telecommunication networks. We consider these networks as multilevel dynamic objects. It shows that reconfigurable systems are necessary for their monitoring process in real life.

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Originally, sensors based on surface acoustic waves are fabricated using photolithography, which becomes extremely expensive when a small series or even single elements are needed for the research. A laser thin film local evaporation technique is proposed to substitute the photolithography process in the production of surface acoustic wave based inertial sensors prototypes. To estimate its potential a prototype of a surface acoustic wave gyroscope sensing element was fabricated and tested.

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Precision Angle Measurement Systems on the Basis of Ring Laser Gyro.

Sensors (Basel)

December 2020

Geodetic Observatory Wettzell, Research Unit Satellite Geodesy, Technical University of Munich, 93444 Bad Koetzting, Germany.

The main application of a ring laser gyroscope is navigation. It is currently the most widely used device for strapdown inertial navigation systems. However, it is also applicable for high-precision angle metrology systems.

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Parkinson's disease (PD) is one of the most common chronic neurological diseases and one of the significant causes of disability for middle-aged and elderly people. Monitoring the patient's condition and its compliance is the key to the success of the correction of the main clinical manifestations of PD, including the almost inevitable modification of the clinical picture of the disease against the background of prolonged dopaminergic therapy. In this article, we proposed an approach to assessing the condition of patients with PD using deep recurrent neural networks, trained on data measured using mobile phones.

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Based on ideas about the molecular vector machine of proteins [1], a database of protein pentafragments has been created and algorithms have been proposed for predicting the secondary structure of proteins according to their primary structure and for designing the primary protein structure for a given secondary structure that it takes on. A comprehensive software suite (Predicto @ Designer) has been developed using the pentafragments database and the said algorithms. For the proteins used to create the pentafragments database, a high accuracy (close to 100%) in predicting the secondary protein structure as well as good prospects for its use for designing secondary structures of proteins have been demonstrated.

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A model of molecular vector machine of proteins.

Biosystems

June 2019

St. Petersburg State Electrotechnical University, Prof. Popov str. 5, 197376, St. Petersburg, Russia. Electronic address:

Based on the analysis of NH⋯OC bond region of the proteins pentafragments using the quantum chemistry representations, a group of 20 vectors of action has been isolated. These vectors of action are reconstructed by a group of 20 side chains of amino acids being the irreducible representations of vectors. As a result, a model of molecular vector machine of proteins (MVM) has been proposed.

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Purpose: Hypertrophic osteoarthropathy (HOA) is a condition that can be inherited or acquired. It causes diffuse periosteal new bone formation on the long bones, with a predilection for the appendicular skeleton. When acquired, it is a nonspecific indicator of systemic disease that arises following a primary condition.

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Multimode high-power laser diodes suffer from inefficient beam focusing, leading to a focal spot 10-100 times greater than the diffraction limit. This inevitably restricts their wider use in 'direct-diode' applications in materials processing and biomedical photonics. We report here a 'super-focusing' characteristic for laser diodes, where the exploitation of self-interference of modes enables a significant reduction of the focal spot size.

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In both prokaryotes and eukaryotes, the survival at temperatures considerably exceeding the optimum is supported by intense synthesis of the so-called heat shock proteins (HSPs), which act to overcome the adverse effects of heat stress. Among mycoplasmas (class Mollicutes), which have significantly reduced genomes, only some members of the Acholeplasmataceae family possess small HSPs of the α-crystallin type. Overproduction of a recombinant HSP IbpA (Hsp20) from the free-living mycoplasma Acholeplasma laidlawii was shown to increase the resistance of Escherichia coli to short-term heat shock.

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A turn on of a quantum dot (QD) semiconductor laser simultaneously operating at the ground state (GS) and excited state (ES) is investigated both experimentally and theoretically. We find experimentally that the slow passage through the two successive laser thresholds may lead to significant delays in the GS and ES turn ons. The difference between the turn-on times is measured as a function of the pump rate of change ɛ and reveals no clear power law.

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Gram-positive bacteria cause a wide spectrum of infectious diseases, including nosocomial infections. While in the biofilm, bacteria exhibit increased resistance to antibiotics and the human immune system, causing difficulties in treatment. Thus, the development of biofilm formation inhibitors is a great challenge in pharmacology.

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Gram-positive bacteria can cause various infections including hospital-acquired infections. While in the biofilm, the resistance of bacteria to both antibiotics and the human immune system is increased causing difficulties in the treatment. Bacillus subtilis, a non-pathogenic Gram-positive bacterium, is widely used as a model organism for studying biofilm formation.

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By means of a computational method, the possibility of radiating a short acoustic pulse by a transducer in the form of a piezoceramic sphere internally filled with liquid is investigated. An electric inductive-resistive circuit is connected to the electric input of the transducer. Solution is obtained based on scheme-analogs theory for piezoceramic transducers, and spectral Fourier transform theory.

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Classification of sparse high-dimensional vectors.

Philos Trans A Math Phys Eng Sci

November 2009

St. Petersburg State Electrotechnical University, 5 Prof. Popov Street, 197376 St. Petersburg, Russia.

We study the problem of classification of d-dimensional vectors into two classes (one of which is 'pure noise') based on a training sample of size m. The main specific feature is that the dimension d can be very large. We suppose that the difference between the distribution of the population and that of the noise is only in a shift, which is a sparse vector.

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Analysis of blood pressure-heart rate feedback regulation under non-stationary conditions: beyond baroreflex sensitivity.

Physiol Meas

July 2009

Institut für Theoretische Physik, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany. Radio Systems Department, St Petersburg State Electrotechnical University, Professor Popov Street 5, 197376 St Petersburg, Russia.

The feedback regulation of blood pressure and heart rate is an important indicator of human autonomic function usually assessed by baroreflex sensitivity (BRS). We suggest a new method yielding a higher temporal resolution than standard BRS methods. Our approach is based on a regression analysis of the first differences of inter-heartbeat intervals and blood pressure values.

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