High resolution crystal structure of Z DNA in complex with Cr3 cations

This work is part of our project aimed at characterizing metal-binding properties of left-handed Z-DNA helices. The three Cr(3+) cations found in the asymmetric unit of the d(CGCGCG)(2)–Cr(3+) crystal structure do not form direct coordination bonds with atoms of the Z-DNA molecule. Instead, the hydrated Cr(3+) ions are engaged in outer-sphere interactions with phosphate groups and O6 and N7 guanine atoms of the DNA. The Cr(3+)(1) and Cr(3+)(2) ions have disordered coordination spheres occupied by six water molecules each. These partial-occupancy chromium cations are 2.354(15) Å apart and are bridged by three water molecules from their hydration spheres. The Cr(3+)(3) cation has distorted square pyramidal geometry. In addition to the high degree of disorder of the DNA backbone, alternate conformations are also observed for the deoxyribose and base moieties of the G2 nucleotide. Our work illuminates the question of conformational flexibility of Z-DNA and its interaction mode with transition-metal cations. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00775-015-1247-5) contains supplementary material, which is available to authorized users

Welding of stainless-duplex steels Properties of welded joints

Translated from Polish (Biuletyn Instytutu Spawalnictwa 2001 45 (2) p. 25-33)Available from British Library Document Supply Centre-DSC:9023.190(10332)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

An assessment of solid-wire film coatings for MAG welding

Solid electrode-wires, intended for MAG welding, are made of common and low-alloy constructional steels and are usually coated with a thin copper film whose role is to ensure good electrical contact in the contact tube (the current terminal), a low level of resistance to feed in the spiral of the MAG welding clamp, and a temporary anticorrosion protection. The present paper contains results of the investigations into the properties of film coatings on G3Sil-EN 440 solid wires. The assessment of the wire properties was based on the criteria established in the course of the experimentation. This was necessary because the available standards for the welding wires do not uniquely specify requirements regarding factors such as, for instance, film thickness, its uniformity and surface roughness which influence the quality of the coatingTranslated from Polish (Biul. Inst. Spawalnictwa 2001 45 (4) p. 53-56)Available from British Library Document Supply Centre-DSC:9023.190(10423)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo