Mechanical forces exerted by laser tweezers or atomic force microscopes can be used to drive rare transitions in single molecules, such as unfolding of a protein or dissociation of a ligand. The phenomenological description of pulling experiments based on Bell's expression for the force-induced rupture rate is found to be inadequate when tested against computer simulations of a simple microscop...

Regulation of genomic activity occurs through the manipulation of DNA by competent mechanoenzymes. Force-clamp optical tweezers that allow the structural dynamics of the DNA molecule to be measured were used here to investigate the kinetics of mechanically-driven strand reannealing. When the force on the torsionally unconstrained λ-phage DNA is decreased stepwise from above to below the overstr...

Many biological processes generate force, and proteins have evolved to resist and respond to tension along different force axes. Single-molecule force spectroscopy allows for molecular insight into the behavior of proteins under force and the mechanism of protein folding in general. Here, we have used src SH3 to investigate the effect of different pulling axes under the low-force regime afforde...

We report the first experimental realization of magnetic trapping of a sample of cold radicals following multistage Zeeman deceleration of a pulsed supersonic beam. H atoms seeded in a supersonic expansion of Kr have been decelerated from an initial velocity of 520 m/s to 100 m/s in a 12-stage Zeeman decelerator and loaded into a magnetic quadrupole trap by rapidly switching the fields of the t...

Trap-awareness and related phenomena whereby successive capture events are not independent is a feature of the majority of capture-recapture studies. This phenomenon was up to now difficult to incorporate in open population models and most authors have chosen to neglect it although this may have damaging consequences. Focusing on the situation where animals exhibit a trap response at the occasi...