The study and prediction of the failure mechanisms affecting long fibre reinforced composites is a fundamental field that provides an essential knowledge for structural design with composites. Transverse failure, generated at ply level by mechanism damage known as inter-fibre/matrix usually determines initiation in any laminate which justifies its relevant role need to understand micromechanica...

There are two alternative pathways by which inverted repeat sequences in supercoiled DNA molecules may extrude cruciform structures, called C-type and S-type. S-type cruciforms, which form the great majority, are characterised by absolute requirement for cations to promote extrusion, which then proceeds at higher temperatures and with lower activation parameters than for C-type cruciforms. The ...

pT181 and other closely related rolling circle plasmids have the nicking site for initiation of replication between the arms of a GC-rich inverted repeat sequence adjacent to the binding site for the dimeric initiator protein. Replication is initiated by the initiator-induced extrusion of this sequence as a cruciform, creating a single-stranded region for nicking by the protein. Nicking is foll...

Holliday junctions form during DNA repair and homologous recombination processes. These processes entail branch migration, whereby the length of two arms of a cruciform increases at the expense of the two others. Branch migration is carried out in prokaryotic cells by the RuvAB motor complex. We study RuvAB-catalyzed branch migration by following the motion of a small paramagnetic bead tethered...

Topoisomerases are essential cellular enzymes that maintain the appropriate topological status of DNA and are the targets of several antibiotic and chemotherapeutic agents. High-throughput (HT) analysis is desirable to identify new topoisomerase inhibitors, but standard in vitro assays for DNA topology, such as gel electrophoresis, are time-consuming and are not amenable to HT analysis. We have...

The cruciform hypothesis states that if a visual evoked potential component originates in V1, then stimuli placed in the upper versus lower visual fields will generate responses with opposite polarity at the scalp. This diagnostic has been used by many studies as a definitive marker of V1 sources. To provide an empirical test of the validity of the cruciform hypothesis, we generated forward mod...

Recombination at stalled replication forks is regulated at an early stage by sumoylation. In this issue of Cell, Branzei et al. show that the Ubc9/SUMO modification pathway controls the accumulation of cruciform structures at stalled forks.