Locomotion of the fish-like foil under own effort

Self-locomotion of the fish-like foil is simulated by the mesh-free method of viscous vortex domains (VVD). The foil consists of three rigid sections connected by the spring hinges. The forcing periodic moment is applied between first and second sections imitating the muscular effort of the fish. The hinge between the second and third sections is elastic and passive. The task is solved as coupled flow-structure interaction

Molecular Characteristics of Chitosan and Structure of its Films Formed from Water Solutions of Acetic and Hydrochloric Acids

Molecular characteristics of chitosan in diluted water solutions of acetic and hydrochloric acids were studied by viscometry, dynamic light scattering, and thin layer chromatography. Chitosan molecules were found to undergo destruction in the solutions of hydrochloric acid and its mixtures with acetic acid. The structure of the chitosan films cast from these solvents was studied by DSC, TGA, and SEM. As shown by electron microscopic data, all the films had an amorphous-crystalline structure but the films prepared from chitosan solutions in diluted hydrochloric acid were characterized by a higher degree of crystallinity. It was supposed that a lower molecular mass of chitosan molecules in the hydrochloric acid solutions results in more extended conformations providing a higher capability of self-organization and formation of regular supermolecular structure. The difference in crystal modification in structure of the films cast of these acids was observed. It was found that the films prepared from the mixtures of acids had a spherulite structure and the crystal modification like ones cast from hydrochloric acid, but with a lower degree of crystallinity

Novel strong tissue specific promoter for gene expression in human germ cells

<p>Abstract</p> <p>Background</p> <p>Tissue specific promoters may be utilized for a variety of applications, including programmed gene expression in cell types, tissues and organs of interest, for developing different cell culture models or for use in gene therapy. We report a novel, tissue-specific promoter that was identified and engineered from the native upstream regulatory region of the human gene <it>NDUFV1 </it>containing an endogenous retroviral sequence.</p> <p>Results</p> <p>Among seven established human cell lines and five primary cultures, this modified <it>NDUFV1 </it>upstream sequence (mNUS) was active only in human undifferentiated germ-derived cells (lines Tera-1 and EP2102), where it demonstrated high promoter activity (~twice greater than that of the SV40 early promoter, and comparable to the routinely used cytomegaloviral promoter). To investigate the potential applicability of the mNUS promoter for biotechnological needs, a construct carrying a recombinant cytosine deaminase (RCD) suicide gene under the control of mNUS was tested in cell lines of different tissue origin. High cytotoxic effect of RCD with a cell-death rate ~60% was observed only in germ-derived cells (Tera-1), whereas no effect was seen in a somatic, kidney-derived control cell line (HEK293). In further experiments, we tested mNUS-driven expression of a hyperactive <it>Sleeping Beauty </it>transposase (SB100X). The mNUS-SB100X construct mediated stable transgene insertions exclusively in germ-derived cells, thereby providing further evidence of tissue-specificity of the mNUS promoter.</p> <p>Conclusions</p> <p>We conclude that mNUS may be used as an efficient promoter for tissue-specific gene expression in human germ-derived cells in many applications. Our data also suggest that the 91 bp-long sequence located exactly upstream <it>NDUFV1 </it>transcriptional start site plays a crucial role in the activity of this gene promoter <it>in vitro </it>in the majority of tested cell types (10/12), and an important role - in the rest two cell lines.</p

A Robotically-Assembled 100-Meter Space Telescope

The future of astronomy may rely on extremely large space telescopes in order to image Earth-sized exoplanets or study the first stars. These telescopes will not be possible without a radical shift in design methods and concepts that are not limited by the size of a single payload fairing. In-Space Telescope Assembly Robotics (ISTAR) is one solution. The ISTAR project has developed a concept for an optical space telescope with a collecting area of nearly 8000 square meters, launched in pieces from the ground, and assembled by highly dexterous robots in space. The concept has been demonstrated to meet optical requirements and failure criteria. This paper focuses on the design and feasibility analysis of the telescope structure, as it has to be stiff and precise enough to maintain optical tolerances while also being amenable to robotic operations. The overall optical scheme of the telescope is first presented, which includes four main elements: a spherical primary mirror roughly hexagonal in shape spanning 100 meters flat to flat; an eyepiece containing all subsequent mirrors and detectors; a metrology system; and a sun shade. The conceived structure that connects and supports these components is then detailed, beginning with the concept of operations and assembly process and ending with the results of a comprehensive structural analysis. Particular attention is given to the truss structure that supports the primary mirror segments, called the backplane. The backplane design uses both robotic assembly and deployable structures to reduce assembly time, featuring expanding truss modules grouped with pre-assembled clusters of mirror segments that are connected together in space. The truss geometry of the structure was chosen from a vast design space, which was first narrowed using “back-of-the-envelope” analytical methods, to satisfy vibrational stiffness and mass criteria. Higher fidelity simulations using finite element analysis and matrix methods were then used to demonstrate that the structure meets optical and failure strength requirements while subjected to loads typically encountered in the space environment. This paper includes many of the decisions and trades made throughout the activity, providing a reference for the design of large modular space structures and laying the groundwork for future flight missions of this nature

Subsea Methane Hydrates: Origin and Monitoring the Impacts of Global Warming

The East Siberian Arctic shelf is the area where the largest natural gas reserves are concentrated. The formation of permafrost of the Arctic shelf during the Ice Age contributed to the emergence of a zone of stable existence of gas hydrates in the sedimentary layer, and subsequent flooding of the shelf led to its gradual degradation, the thawing of gas hydrates and the subsequent emissions of methane into the atmosphere. In the first part of the paper, we use mathematical modeling to study the processes of the formation of subsea permafrost on the Arctic shelf considering changes in the sea levels over the past 200 thousand years. Numerical simulations show the influence of climate warming up to 2200 on the degradation of subsea permafrost and the violation of the conditions for the stable existence of methane hydrates in bottom sediments using the example of the East Siberian shelf. The second part of the paper proposes a method for seismic monitoring of the state of gas hydrates based on a solution of multi-parameter inverse seismic problems. In particular, the degree of attenuation of seismic energy is one of the objective parameters for assessing the consolidation of gas hydrates: the closer they are to the beginning of decomposition, the higher the attenuation and, hence, the lower the quality factor. In this publication, we do not solve a multi-parameter inverse seismic problem for a real geological object. This would be impossible due to the lack of necessary data. Instead, we focus on substantiating the possibility of correct solutions for the problem of the reconstruction of the absorption and velocities for a viscoelastic medium in relation to the problem of monitoring the state of gas hydrate deposits. As noted in a range of publications, the thawing of gas hydrates leads to an increase in the fluid saturation of the geological medium followed by an increase in the absorption of seismic energy—that is, a decrease in the quality factor. Thus, the methods of seismic monitoring of the state of gas hydrates to predict the possibility of developing dangerous scenarios should be based on solving a multi-parameter inverse seismic problem. This publication is devoted to the presentation of this approach

The Views of Special Education Department Students on the Use of Assistive Technologies in Special Education

Assistive technologies are an important factor for individuals with special needs to benefit from educational services. The aim of this research is to determine the opinions and thoughts of special education students on the use of technologies. The study group of the research consisted of 41 teacher candidates studying in Cyprus and Russian universities in the special education department in their classes in the fall semester of the 2020–2021 academic year. With regard to the collection of research data, it aims to determine students’ views with the ‘Personal Information Form’ developed by the researchers to determine the demographic characteristics of the research group and the ‘Semi-Structured Interview Form’ prepared by the researchers. The descriptive analysis method was used in the analysis of the data obtained from the interview questions. As a result of the research, special education teacher candidates’ use of the assistive technologies is given in detail in the results section

Chlorin content, magnetic susceptibility, and lightness records of sediment core LV53-27 (Sea of Japan, 2010)

Sediment core LV53-27 (41° 54′ N, 132° 33′ E) was retrieved in the northwestern Sea of Japan (Pervenets Seamount) at 1698 m depth during a joint Russian-Chinese expedition LV53 on RV “Akademik M.A. Lavrentyev” in 2010-11-10T23:39:00. The 757-cm long core was characterized by clay/silty clay sediments with alternating dark and light layers. in order to investigate millenial-scale climate changes with ultra-high resolution digital image of this sediment core was processed. Sediment core LV53-27 recovered about 120 kyr according to age model (Gorbarenko et al., submitted to Global and Planetary Changes). Age model was based on correlation of magnetic susceptibility, chlorin content and lightness records with similar records of well-dated sediment core MD01-2407. The magnetic susceptibility (MS) of the sediments was measured in cube samples throughout the core at 2-cm intervals using an AGICO Kappabridge MFK1-FA. These measurements were performed at the Laboratory of Cenozoic Geology and Paleomagnetism of the North-East Interdisciplinary Scientific Research Institute in Magadan, Russia. Data presented as natural logarithm of units SI (International System of Units) Chlorin content was measured with pretreatment procedures and analytical reagents, as proposed by Harris et al. (1996), using a Shimadzu UV-1650PC spectrophotometer at 1 cm resolution. Color lightness (CL) of the sediments was measured using the original photocolorimeter based on a Canon 50D digital camera. One-meter core sections with 14 cm diameter were split into two halves, while performing surface smoothing. Two flash units with soft boxes were used for creating an even and diffused illumination of the sediment surface. Camera shooting was performed with the following settings: ISO 100, 1/100'' exposure, and 8.0 focal ratio. Every image covered approximately 40 cm of the core section with approximately 11 pixels per 1 mm stratigraphic resolution. The X-rite Color Checker was used for calibrating the white balance of each image. Digital images were processed with the RTImageProc software for calculating the CL data from black (0) to white (255) with 1-pixel resolution and averaged with 1 mm step. Need to note that the width of the analyzed window of each image (80 mm) in the studied core allow to significantly reduce the possible effect of the sediment bioturbation by organisms several millimeters in diameter

Oncobox Bioinformatical Platform for Selecting Potentially Effective Combinations of Target Cancer Drugs Using High-Throughput Gene Expression Data

Sequential courses of anticancer target therapy lead to selection of drug-resistant cells, which results in continuous decrease of clinical response. Here we present a new approach for predicting effective combinations of target drugs, which act in a synergistic manner. Synergistic combinations of drugs may prevent or postpone acquired resistance, thus increasing treatment efficiency. We cultured human ovarian carcinoma SKOV-3 and neuroblastoma NGP-127 cancer cell lines in the presence of Tyrosine Kinase Inhibitors (Pazopanib, Sorafenib, and Sunitinib) and Rapalogues (Temsirolimus and Everolimus) for four months and obtained cell lines demonstrating increased drug resistance. We investigated gene expression profiles of intact and resistant cells by microarrays and analyzed alterations in 378 cancer-related signaling pathways using the bioinformatical platform Oncobox. This revealed numerous pathways linked with development of drug resistant phenotypes. Our approach is based on targeting proteins involved in as many as possible signaling pathways upregulated in resistant cells. We tested 13 combinations of drugs and/or selective inhibitors predicted by Oncobox and 10 random combinations. Synergy scores for Oncobox predictions were significantly higher than for randomly selected drug combinations. Thus, the proposed approach significantly outperforms random selection of drugs and can be adopted to enhance discovery of new synergistic combinations of anticancer target drugs