213 research outputs found
MULTIPROCESSOR MODELING TECHNOLOGIES FOR THE APPLIED STATISTICAL TASKS
The work considers the multiprocessors technologies of modeling for Monte Carlo tasks. It is shown that only application of the modern super productive systems permitted the new way to realize the mechanism of corresponding partitioned computations. The calculating schemes that supply to provide the increase of productivity and calculations' speed effectiveness are shown. In this article the modified algorithm of parallel calculations is offered based on the Monte Carlo method. Here every calculator has its own random generator of numbers. Thus intermediate calculations come true independently on the different, separately taken blades of cluster, "calculators". The results are already processed on some separately taken master -blades ("analyzer"). This allows to get rid from the necessary presence of router-communicator between the random generator of numbers and "calculator". Obviously, that such decision allows to accelerate the process of calculations. It is shown that the parallel algorithms of the Monte Carlo method are stable to any input data and have the maximal parallel form and, thus, minimal possible time of realization using the parallel computing devices. If it is possible to appoint one processor to one knot of calculation. Thus the realization of calculations becomes possible in all knots of net area in parallel and simultaneously.The work considers the multiprocessors technologies of modeling for Monte Carlo tasks. It is shown that only application of the modern super productive systems permitted the new way to realize the mechanism of corresponding partitioned computations. The calculating schemes that supply to provide the increase of productivity and calculations' speed effectiveness are shown. In this article the modified algorithm of parallel calculations is offered based on the Monte Carlo method. Here every calculator has its own random generator of numbers. Thus intermediate calculations come true independently on the different, separately taken blades of cluster, "calculators". The results are already processed on some separately taken master -blades ("analyzer"). This allows to get rid from the necessary presence of router-communicator between the random generator of numbers and "calculator". Obviously, that such decision allows to accelerate the process of calculations. It is shown that the parallel algorithms of the Monte Carlo method are stable to any input data and have the maximal parallel form and, thus, minimal possible time of realization using the parallel computing devices. If it is possible to appoint one processor to one knot of calculation. Thus the realization of calculations becomes possible in all knots of net area in parallel and simultaneously
Phase transitions on the surface of a carbon nanotube
A suspended carbon nanotube can act as a nanoscale resonator with remarkable
electromechanical properties and the ability to detect adsorption on its
surface at the level of single atoms. Understanding adsorption on nanotubes and
other graphitic materials is key to many sensing and storage applications. Here
we show that nanotube resonators offer a powerful new means of investigating
fundamental aspects of adsorption on carbon, including the collective behaviour
of adsorbed matter and its coupling to the substrate electrons. By monitoring
the vibrational resonance frequency in the presence of noble gases, we observe
the formation of monolayers on the cylindrical surface and phase transitions
within these monolayers, and simultaneous modification of the electrical
conductance. The monolayer observations also demonstrate the possibility of
studying the fundamental behaviour of matter in cylindrical geometry.Comment: Unpublished; 7 pages with 4 figures plus 3 pages of supplementary
materia
Anthropogenic and natural factors shaping the boundaries of the St. Petersburg suburban area
The suburban area of St. Petersburg stands out as Russia's most complex in terms of spatial structure, encompassing districts ranging from the suburban imperial residences of the 18th century to low-rise residential zones and modern multi-storey developments of the 21st century. This study concluded that extensive stretches of the administrative border between St. Petersburg and the Leningrad region divide homogeneous territories. Therefore, it makes little academic or practical sense to confine scholarly efforts solely to suburbs situated on one side of this border. The principal factor in delineating the St. Petersburg urban area is the transport accessibility of territories surrounding the city. It was empirically determined that the inner boundary of the suburban area is located approximately within the 40-45-minute isochrone from the city centre, while the outer boundary extends to the 2-hour isochrone. In the conditions of today's St. Petersburg, a two-hour isochrone corresponds to a 60 km distance. Along with isochrones, the actual boundary of the suburban area is determined by several natural and anthropogenic factors. In terms of the natural environment, a significant part of the St. Petersburg suburban area is anthropogenic forest-steppe, whose landscapes are radically different from those of the area’s natural southern taiga subzone. The features of the 'forest steppe' reach their peak to the southwest and south of St. Petersburg. To the north of the city, the suburban zone is defined by both ‘anthropogenic forest-steppe’ and secondary small-leaved forests that have replaced agricultural lands. Another prominent feature is parks found on the premises of former estates where introduced woody species account for a substantial portion of vegetation. The spatial structure of the suburban area north of St. Petersburg is complicated by large extents of unpopulated areas. Since the 19th century, they have divided the area into two virtually disconnected parts
CLINICAL EFFICACY AND SAFETY OF ADEMETIONINE IN PATIENTS WITH DIABETES-ASSOCIATED OSTEOARTHRITIS: A CROSS-OVER PILOT STUDY
Osteoarthritis (OA) is one of most common rheumatic diseases, and currently there is no effective pharmacological treatment of OA. It has been suggested that lack of effective treatment is, in part, due to the disease heterogeneity which may lead to development of several OA subtypes (phenotypes). Diabetes-associated OA is among the proposed OA phenotypes. The key mechanism involved into inflammatory and degenerative changes in OA is a decrease in DNA methylation suggested for several cell types, that was also demonstrated in type 2 diabetes mellitus. Therefore, pharmacological increase of DNA methylation may be an effective treatment strategy which may exert pleiotropic effects in diabetes-associated OA. In a randomized crossover study, we have evaluated efficacy and safety of ademetionine, a methyl group donor, in comparison with chondroitine sulfate in patients with OA associated with type 2 diabetes mellitus. The patients were randomly assigned to sequential treatment of chondroitine sulfate/ademetionine or ademetionine/chondroitine sulfate during one month, with a washout period of 2 weeks. The primary endpoint was pain measured according to visual analogue scale (VAS). Painful symptoms, as well as function and disease signs in knee, hip and hand joints were also assessed with KOOS, WOMAC, and FIHOA scales. General performance was assessed with SF–36 scale. To evaluate systemic inflammation, we measured serum IL-6, IL-18, adiponectin, and CRP using ELISA technique. Concentrations of serum cartilage destruction biomarkers (aggrecan and antibodies to collagen type II) were assessed by ELISA. Serum lipid levels were measured with standard method; glycated hemoglobin was assessed with liquid chromatography. Ten patients (all women, age 61.7-74.2 year with BMI of 1.1-38.4 kg/m2) were included in the study. It has been demonstrated that ademetionine showed a statistically significant analgetic effect (decrease in VAS pain), improved knee function and reduced symptoms in knee joints (as measured by KOOS subscales), and did not influence the levels of systemic inflammation or cartilage destruction biomarkers. There was also no change in lipid levels and glycated hemoglobin concentrations. Ademetionine was well tolerated, no serious adverse events occurred during the treatment. In conclusion, ademetionine does not have pleiotropic pharmacological effects in diabetes-associated OA. Its potential application in cases of different comorbidities requires further studies
Cytoprotective effect of non-opioid leu-enkephalin analogue in primary culture of pulmonary fibroblasts in oxidative stress
Aim. Analysis of the cytoprotective effect of non-opioid leu-enkephalin analogue (Phe-D-Ala-Gly-Phe-Leu-Arg) in the primary culture of pulmonary fibroblasts in conditions of oxidative stress.
Methods. Pulmonary fibroblasts were incubated with the peptide of non-opioid leu-enkephalin analogue (Phe-D-Ala-Gly-Phe-Leu-Arg) in the concentration 0.1 μM for 6 hours. To simulate oxidative stress, 60 μM H2O2 was added to the culture medium for 2 hours. Experimental series included (1) «control»; (2) «non-opiate leu-enkephalin analogue» (the peptide was added to the culture medium 44 hours after the final passage); (3) «oxidative stress» (H2O2 was added to the culture medium 48 hours after the final passage); (4) «non-opiate leu-enkephalin analogue + oxidative stress» (the peptide and H2O2 were added to the culture medium 44 and 48 hours respectively after the final passage). In order to evaluate the generation of superoxide anion by pulmonary fibroblasts, the method of lucigenin-dependent chemiluminescence was used. Computer morphometry of the nucleo-nucleolar apparatus of fibroblasts stained with silver nitrate by the AgNOR method was used to assess the cell state: the area of fibroblast nuclei, the total nucleoli area in the nucleus, and the number of nucleoli in the nucleus were measured. These parameters correlate with the activity of anabolic processes in the cells.
Results. The effect of H2O2 on the primary culture of pulmonary fibroblasts caused an increase of superoxide anion generation by the fibroblasts, reduction of fibroblast nuclei size, decrease of nucleoli amount and size. Pre-incubation of pulmonary fibroblasts with a non-opioid leu-enkephalin analogue reduced the H2O2-induced generation of superoxide anion, corrected changes in the nucleo-nucleolar apparatus of fibroblasts caused by oxidative stress. In our previous studies, similar effect in the same model was shown for non-selective μ/δ-opioid receptor agonist peptide sedatin (dermorphin analogue). The mechanism of cytoprotective effect of non-opioid leu-enkephalin analogue may include the affinity of this peptide to nociceptin receptors (NOR receptors) that requires further studies.
Conclusion. The results of the study indicate a direct cytoprotective effect of the peptide Phe-D-Ala-Gly-Phe-Leu-Arg (non-opioid leu-enkephalin analogue) in oxidative stress
Coupling carbon nanotube mechanics to a superconducting circuit
The quantum behaviour of mechanical resonators is a new and emerging field
driven by recent experiments reaching the quantum ground state. The high
frequency, small mass, and large quality-factor of carbon nanotube resonators
make them attractive for quantum nanomechanical applications. A common element
in experiments achieving the resonator ground state is a second quantum system,
such as coherent photons or superconducting device, coupled to the resonators
motion. For nanotubes, however, this is a challenge due to their small size.
Here, we couple a carbon nanoelectromechanical (NEMS) device to a
superconducting circuit. Suspended carbon nanotubes act as both superconducting
junctions and moving elements in a Superconducting Quantum Interference Device
(SQUID). We observe a strong modulation of the flux through the SQUID from
displacements of the nanotube. Incorporating this SQUID into superconducting
resonators and qubits should enable the detection and manipulation of nanotube
mechanical quantum states at the single-phonon level
COMPOSITION OF ESSENTIAL OIL OF TANACETUM VULGARE L. FROM SAMARA REGION
Aim - to analyze the essential oil isolated from the tansy (Tanacetum vulgare L.) flowers harvested from the spontaneous flora of Samara region. Materials and methods. The analysis was made on head flowers of Tanacetum vulgare harvested from the spontaneous flora of Samara region during the flowering stage (July), in 2016. The isolation of the essential oil was made in accordance with the Pharmacopeia of the Russian Federation XIIIth Edition. The essential oil was analyzed using a gas chromatograph coupled with mass-spectrometer apparatus. GCMS analysis was performed using an Agilent Technologies 7820F gas-chromatograph, series MSD, Agilent 5975. Results. It was determined that the major compounds of essential oil are represented by 2 isomers of thujone, eucalyptole (1,8-cineole) and yomogi-alcohol. According to the results of headspace analysis, the main identified components were artemisia alcohol, sabinene, eucalyptole (1,8-cineole). Conclusion. The knowledge of phytochemical characteristics of Tanacetum vulgare L. is important for the correct identification of the plant material for medical purposes
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