179 research outputs found
Multifractal analysis of stress time series during ultrathin lubricant film melting
Melting of an ultrathin lubricant film confined between two atomically flat
surfaces is we studied using the rheological model for viscoelastic matter
approximation. Phase diagram with domains, corresponding to sliding, dry, and
two types of friction regimes has been built taking into account
additive noises of stress, strain, and temperature of the lubricant. The stress
time series have been obtained for all regimes of friction using the
Stratonovich interpretation. It has been shown that self-similar regime of
lubricant melting is observed when intensity of temperature noise is much
larger than intensities of strain and stress noises. This regime is defined by
homogenous distribution, at which characteristic stress scale is absent. We
study stress time series obtained for all friction regimes using multifractal
detrended fluctuation analysis. It has been shown that multifractality of these
series is caused by different correlations that are present in the system and
also by a power-law distribution. Since the power-law distribution is related
to small stresses, this case corresponds to self-similar solid-like lubricant.Comment: 22 pages, 10 figures, 41 reference
Dynamic light- and acetate-dependent regulation of the proteome and lysine acetylome of Chlamydomonas
Metabolic Engineering of Cofactor F420 Production in Mycobacterium smegmatis
Cofactor F420 is a unique electron carrier in a number of microorganisms including Archaea and Mycobacteria. It has been shown that F420 has a direct and important role in archaeal energy metabolism whereas the role of F420 in mycobacterial metabolism has only begun to be uncovered in the last few years. It has been suggested that cofactor F420 has a role in the pathogenesis of M. tuberculosis, the causative agent of tuberculosis. In the absence of a commercial source for F420, M. smegmatis has previously been used to provide this cofactor for studies of the F420-dependent proteins from mycobacterial species. Three proteins have been shown to be involved in the F420 biosynthesis in Mycobacteria and three other proteins have been demonstrated to be involved in F420 metabolism. Here we report the over-expression of all of these proteins in M. smegmatis and testing of their importance for F420 production. The results indicate that co–expression of the F420 biosynthetic proteins can give rise to a much higher F420 production level. This was achieved by designing and preparing a new T7 promoter–based co-expression shuttle vector. A combination of co–expression of the F420 biosynthetic proteins and fine-tuning of the culture media has enabled us to achieve F420 production levels of up to 10 times higher compared with the wild type M. smegmatis strain. The high levels of the F420 produced in this study provide a suitable source of this cofactor for studies of F420-dependent proteins from other microorganisms and for possible biotechnological applications
Advancing understanding of microbial bioenergy conversion processes by activity-based protein profiling
Inheritance by Aggregation
Inheritance is an important concept in object-oriented programming. The mechanisms provided by many existing programming languages combine reuse of types and reuse of implementations. These mechanisms often violate encapsulation. Changes to an inheritance hierarchy affect related implementations. We separate type and class (implementation) and identify visibility of attributes and the binding of attributes to names as basic dimensions of class-based inheritance. To retain encapsulation [12] we state requirements to an inheritance mechanism and show how to fulfill them with an approach to inheritance by aggregation. Initialization is used to change bindings of attributes. 2 1. Introduction Inheritance is an important concept in object-oriented programming languages. It is used for differential programming, refinement and reuse. In existing languages inheritance is realized by a special mechanism which ought to fulfill these aspects. The major advantage of object-oriented programming ..
Effect of hot-air ageing on properties of ethylene–propylene–diene monomer (EPDM) rubber/samarium borate/polyolefin and EPDM/antimony-doped tin oxide/polyolefin composites
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