Evaluation of the resistance force of magnetorheological fluid damper

The aim of this research was to examine the resistance force generated by linear hydro-cylinder type magnetorheological fluid (MRF) damper acting in different regimes. MRF damper performance has been investigated experimentally by using universal computerized material properties testing machine. Measurements of resistance force have been carried out for different speeds of the damper piston motion under different strength of the magnetic field. Dependences of the force on these parameters (speed and magnetic field strength) have been obtained. It was defined, that the force increases practically linearly when increasing strength of the magnetic field and when increasing piston speed

Dynamics of tactile device drive

A study of novel tactile device transient processes that occurs during the information transmission has been described. Mathematical model has been presented and investigation of pin drive dynamics were performed. Results of investigations allowed us to evaluate the influence of drive parameters and operating regimes on the pin motion, and may be used in engineering practice for tactile device developmen

Loading characteristics of weight stack machines

The load characteristics of the weight stack machines, where the resistance is generated by inertia of the stack of masses, are the subject of the paper. The method and means of experimental research are described. The dependencies of inertial resistance load upon the rate of exercises and the stack weight are determine

Analyses of protein cores reveal fundamental differences between solution and crystal structures

There have been several studies suggesting that protein structures solved by NMR spectroscopy and x-ray crystallography show significant differences. To understand the origin of these differences, we assembled a database of high-quality protein structures solved by both methods. We also find significant differences between NMR and crystal structures---in the root-mean-square deviations of the C$_{\alpha}$ atomic positions, identities of core amino acids, backbone and sidechain dihedral angles, and packing fraction of core residues. In contrast to prior studies, we identify the physical basis for these differences by modelling protein cores as jammed packings of amino-acid-shaped particles. We find that we can tune the jammed packing fraction by varying the degree of thermalization used to generate the packings. For an athermal protocol, we find that the average jammed packing fraction is identical to that observed in the cores of protein structures solved by x-ray crystallography. In contrast, highly thermalized packing-generation protocols yield jammed packing fractions that are even higher than those observed in NMR structures. These results indicate that thermalized systems can pack more densely than athermal systems, which suggests a physical basis for the structural differences between protein structures solved by NMR and x-ray crystallography.Comment: 9 pages, 4 figure

Using physical features of protein core packing to distinguish real proteins from decoys

The ability to consistently distinguish real protein structures from computationally generated model decoys is not yet a solved problem. One route to distinguish real protein structures from decoys is to delineate the important physical features that specify a real protein. For example, it has long been appreciated that the hydrophobic cores of proteins contribute significantly to their stability. As a dataset of decoys to compare with real protein structures, we studied submissions to the bi-annual CASP competition (specifically CASP11, 12, and 13), in which researchers attempt to predict the structure of a protein only knowing its amino acid sequence. Our analysis reveals that many of the submissions possess cores that do not recapitulate the features that define real proteins. In particular, the model structures appear more densely packed (because of energetically unfavorable atomic overlaps), contain too few residues in the core, and have improper distributions of hydrophobic residues throughout the structure. Based on these observations, we developed a deep learning method, which incorporates key physical features of protein cores, to predict how well a computational model recapitulates the real protein structure without knowledge of the structure of the target sequence. By identifying the important features of protein structure, our method is able to rank decoys from the CASP competitions equally well, if not better than, state-of-the-art methods that incorporate many additional features.Comment: 7 pages, 5 figure

Pagrindinio žemės dirbimo įtaka dirvožemio sėklų bankui ir piktžolėtumui javų bei žolių sėjomainoje

In the shallow ploughing and shallow ploughless tillage treatments there were found 25.5% and 41.5% more weed seed species in the soil, compared with the conventional tillage treatment. The seeds of Chenopodium album L., Persicaria lapathifolia L., Fallopia convolvulus L. and Viola arvensis Murray were found in all tillage treatments. The distribution of F. convolvulus L., P. lapathifolia L. seeds was significantly influenced by soil tillage only, that of V. arvensis Murray by soil tillage and its interaction with soil fertility improvement measures, and that of Ch. album L. by soil fertility improvement measures only

Metabolic and mitochondria alterations induced by SARS-CoV-2 accessory proteins ORF3a, ORF9b, ORF9c and ORF10

Antiviral signaling, immune response and cell metabolism are dysregulated by SARS-CoV-2, the causative agent of COVID-19. Here, we show that SARS-CoV-2 accessory proteins ORF3a, ORF9b, ORF9c and ORF10 induce a significant mitochondrial and metabolic reprogramming in A549 lung epithelial cells. While ORF9b, ORF9c and ORF10 induced largely overlapping transcriptomes, ORF3a induced a distinct transcriptome, including the downregulation of numerous genes with critical roles in mitochondrial function and morphology. On the other hand, all four ORFs altered mitochondrial dynamics and function, but only ORF3a and ORF9c induced a marked alteration in mitochondrial cristae structure. Genome-Scale Metabolic Models identified both metabolic flux reprogramming features both shared across all accessory proteins and specific for each accessory protein. Notably, a downregulated amino acid metabolism was observed in ORF9b, ORF9c and ORF10, while an upregulated lipid metabolism was distinctly induced by ORF3a. These findings reveal metabolic dependencies and vulnerabilities prompted by SARS-CoV-2 accessory proteins that may be exploited to identify new targets for intervention