Glutamyl-tRNAGln amidotransferase in Deinococcus radiodurans may be confined to asparagine biosynthesis

Asparaginyl-tRNA (Asn-tRNA) and glutaminyl-tRNA (Gln-tRNA) are essential components of protein synthesis. They can be formed by direct acylation by asparaginyl-tRNA synthetase (AsnRS) or glutaminyl-tRNA synthetase (GlnRS). The alternative route involves transamidation of incorrectly charged tRNA. Examination of the preliminary genomic sequence of the radiation-resistant bacterium Deinococcus radiodurans suggests the presence of both direct and indirect routes of Asn-tRNA and Gln-tRNA formation. Biochemical experiments demonstrate the presence of AsnRS and GlnRS, as well as glutamyl-tRNA synthetase (GluRS), a discriminating and a nondiscriminating aspartyl-tRNA synthetase (AspRS). Moreover, both Gln-tRNA and Asn-tRNA transamidation activities are present. Surprisingly, they are catalyzed by a single enzyme encoded by three ORFs orthologous to Bacillus subtilis gatCAB. However, the transamidation route to Gln-tRNA formation is idled by the inability of the discriminating D. radiodurans GluRS to produce the required mischarged Glu-tRNAGln substrate. The presence of apparently redundant complete routes to Asn-tRNA formation, combined with the absence from the D. radiodurans genome of genes encoding tRNA-independent asparagine synthetase and the lack of this enzyme in D. radiodurans extracts, suggests that the gatCAB genes may be responsible for biosynthesis of asparagine in this asparagine prototroph.

Dynamic investigation of an ancient masonry bell tower with operational modal analysis: a non-destructive experimental technique to obtain the dynamic characteristics of a structure

This paper shows the results of an experimental analysis on the bell tower of “Chiesa della Maddalena” (Mola di Bari, Italy), to better understand the structural behavior of slender masonry structures. The research aims to calibrate a numerical model by means of the Operational Modal Analysis (OMA) method. In this way realistic conclusions about the dynamic behavior of the structure are obtained. The choice of using an OMA derives from the necessity to know the modal parameters of a structure with a non-destructive testing, especially in case of cultural-historical value structures. Therefore by means of an easy and accurate process, it is possible to acquire in-situ environmental vibrations. The data collected are very important to estimate the mode shapes, the natural frequencies and the damping ratios of the structure. To analyze the data obtained from the monitoring, the Peak Picking method has been applied to the Fast Fourier Transforms (FFT) of the signals in order to identify the values of the effective natural frequencies and damping factors of the structure. The main frequencies and the damping ratios have been determined from measurements at some relevant locations. The responses have been then extrapolated and extended to the entire tower through a 3-D Finite Element Model. In this way, knowing the modes of vibration, it has been possible to understand the overall dynamic behavior of the structure.

Seismic behavior of a masonry chimney with severe cracking condition: preliminary study

This paper presents a structural analysis of a masonry chimney built in the 1940s, which is currently being cataloged as local interest heritage. This structure has not served any industrial purpose for the last thirty years. The chimney is located in the town of Agost (Alicante - Spain) and directly exposed to the prevailing winds from the sea, as it is approximately 12 km away from the waterfront and there are not any significant barriers, which could protect the structure against the wind. There are longitudinal cracks and fissures all along the shaft because of the chimney’s geometrical characteristics, the effect of the masonry creep and especially the lack of maintenance. Moreover, there is also a permanent bending deformation in the upper 1/3 of the height due to the wind pressure. A numerical analysis for the static behavior against gravity and wind loads was performed using the structure’s current conditions after a detailed report of its geometry, its construction system and the cracking pattern. Afterwards, the dynamic behavior was studied, i.e. a seismic analysis using both response spectra and accelerograms in order to examine the structural stability. This work shows the pre-monitoring analysis before any experimental testing. Using the current results the future test conditions will be determined (e.g. number of sensors and monitoring point location, excitation systems, etc) prior to a possible structural reinforcement by applying composite material (fiber reinforced polymers).

Optimal model through identified frequencies of a masonry building structure with wooden floors

The paper presents the analysis of an important historical building: the Saint James Theater in the city of Corfù (Greece) actually used as the Municipality House. The building, located in the center of the city, is made of carves stones and is characterized by a stocky shape and by the presence of wooden floors. The study deals with the structural identification of such structure through the analysis of its ambient vibrations recorded by means of accelerometers with high accuracy. A full dynamic testing was developed using ambient vibrations to identify the main modal parameters and to make a non-destructive characterization of this building. The results of these dynamic tests are compared with the modal analysis of a complex finite element (FE) simulation of the structure. This analysis may present several problems and uncertainties for this stocky building. Due to the presence of wooden floors, the local modes can be highly excited and, as a consequence, the evaluation of the structural modal parameters presents some difficulties.

Geographic Scope Under Conditions Of Confined And Connected Change: The Case Of Telefónica (Spain). ACES Working Papers, 2012

Traditional explanations of MNE geographic scope formation fit somewhat uncomfortably with recent empirical and theoretical work in IB that suggests (1) that wholesale (not just gradual) changes in MNE geographic scope may be more frequent than previously thought, and (2) that managers’ responses to a world increasingly characterized by random, unpredictable change are more experimental and less optimizing in nature than assumed in most models of international expansion. In this paper we draw from studies portraying industries as dynamic networks, and from the literature on managerial cognition to provide a complementary explanation of the evolution of MNE geographic scope that reconciles the insights of traditional IB models with the questions raised by more recent studies in this field. We illustrate the proposed model through a detailed account of the internationalization process of Telefonica, the Spanish telecommunications company.

Working in confined spaces.

Mode of access: Internet.

Permit-required confined spaces (permit spaces).

"OSHA 3138."

Brickwork & masonry, a practical text book for students & those engaged in the design & execution of structures in brick & stone;

Mode of access: Internet.

The mechanic's companion : or, The elements and practice of carpentry, joinery, bricklaying, masonry, slating, plastering, painting, smithing, and turning, comprehending the latest improvements and containing a full description of the tools belonging to each branch of business, with copious directions for their use, an explanation of the terms used in each art and an introduction to practical geometry /

Mode of access: Internet.

Operative masonry; or, A theoretical and practical treatise of building; containing a scientific account of stones, clays, bricks, mortars, cements, &c.; a description of their component parts, with the manner of preparing and using them. The fundamental rules in geometry, on masonry and stone-cutting, with their application to practice. Illustrated with forty copper-plate engravings.

Republished in 1846 with title: Practical masonry: or A theoretical and operative treatise of building ...

Navigation dam masonry.

Cover title.

Treatises on architecture, building, masonry, joinery, and carpentry /

Includes bibliographical references.

Effect of mortar properties on strength of masonry /

"Issued November 20, 1961."

A treatise on masonry construction.

Has p. 78, 78a-78j; 79a-79m; 112a-112z; 113a-113b.

The builders : a story & study of masonry /

Includes bibliographical references (pages [299]-304) and index.