Sheep are often used as preclinical large animal models for testing the therapeutic potential of multipotent mesenchymal stem cells (MMSCs). A cell culture with characteristics typical for MMSCs was ...obtained due to optimization of the method of cell isolation from sheep bone marrow (BM) in a Ficoll density gradient. The advantage of using SepMate-15 tube compared to the isolation by the classical method has been demonstrated. The obtained cells demonstrated a strong adhesion to the culture plastic, fibroblast-like morphology, and, being induced in vitro, the ability to differentiate into cells of adipose, bone, and cartilage tissues. Adipogenic differentiation was confirmed on day 14, when adipocytes with lipid vesicles positive for Oil Red O specific staining had been formed. On day 14, specific alkaline phosphatase activity appeared in cells in osteogenic medium. Von Kossa staining revealed the presence of insoluble calcium salts in the intercellular space. Chondrogenic differentiation appeared on day 14 and was accompanied with the formation of multilayer structures with an abandon matrix, in which the isogenic groups that resemble hyaline cartilage lacunae were visualized. On day 21, the cells formed tight microgranules with glycosaminoglycan matrixes. Cells were cryopreserved in three different media at the zero passage. A comparative analysis of cell viability was then performed, which revealed a relatively good cell state (more than 70% of live cells). The MMSCs culture obtained from sheep BM was deposited at two to three passages in the specialized Collection of Somatic Cell Cultures of Agricultural and Industrial Animals at the All-Russian Research Institute of Experimental Veterinary Medicine of Russian Academy of Science and could be used in preclinical studies.
Objectives - to evaluate the latent period of complex sensory-motor reaction ^SMR) to relevant visual stimuli in virtual reality (VR) with personalized and indifferent content. Material and methods. ...The study included 10 healthy right-handed males aged 18-19. The selection of subjects in groups was based on two VR scenarios, the content of which reflected (personalized VR) or did not reflect their personal experience (indifferent VR). The latent period of CSMR to relevant visual stimuli was registered using a gamepad and an EEG recording system (BP-010302 BrainAmp Standart 128) in the oddball paradigm. VR scenarios were demonstrated using Oculus Rift CV1 headset. Registration of СSMR in personalized and indifferent VRs was done in three sessions with the interval of 24 hours. Each session lasted 7-8 minutes and included 30-40 CSMR registrations. Igroup Presence Questionnaire (IPQ) was used for subjective evaluation of VR immersiveness. The collected data was processed with IBM SPSS Statistics 22 software. Results. Statistically significant correlations were registered only in VR with personalized content, between the latent time of CSMR and indexes of spatial presence (0.694522) and a general effect of VR immersiveness (-0.592243). It was noted that latent period of CSMR to relevant visual stimuli in VR is determined by the semantic content: the time of CSMR to relevant stimuli in personalized VR was significantly less, than to those in indifferent VR. Conclusion. We support the adequacy of the methodology of studying the mechanisms of human voluntary attention with inclusion of personalized scenes in VR content. It is suggested that such methodology is promising for neurorehabilitation of patients with age-related cognitive impairment
A virtual instrument has been designed to measure the operating efficiency of hydroelectric equipment. A mathematical model of the dynamic systematic error of a measurement is obtained, which is used ...to optimize the mode of operation of the instrument. A test bench is developed for checking similar virtual instruments.
We study
Σ
-definability of countable models over hereditarily finite {ie193-01} superstructures over the field ℝ of reals, the field ℂ of complex numbers, and over the skew field ℍ of quaternions. ...In particular, it is shown that each at most countable structure of a finite signature, which is
Σ
-definable over {ie193-02} with at most countable equivalence classes and without parameters, has a computable isomorphic copy. Moreover, if we lift the requirement on the cardinalities of the classes in a definition then such a model can have an arbitrary hyperarithmetical complexity, but it will be hyperarithmetical in any case. Also it is proved that any countable structure
Σ
-definable over {ie193-03}, possibly with parameters, has a computable isomorphic copy and that being
Σ
-definable over {ie193-04} is equivalent to being
Σ
-definable over {ie193-05}.
Periodic motions of essentially non-linear self-sustained oscillatory systems, described by Rayleigh and Van der Pol equations, are constructed and investigated. The period and initial value of the ...velocity of the system, which determine the self-sustained oscillations of the oscillators for small and moderately large values of the feedback factors, are calculated by the Lyapunov-Poincaré method using a developed accelerated-convergence algorithm and a continuation with respect to a parameter. The trajectories and limit cycles are also constructed with a guaranteed relative and absolute error. The qualitative features of the self-sustained oscillations due to an increase in the self-excitation factors are established and the oscillators are compared. The results of a numerical investigation of periodic solutions of the Van der Pol equation are compared with familiar solutions.
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