We have used a biomembrane force probe decorated with P-selectin to form point attachments with PSGL-1 receptors on a human neutrophil (PMN) in a calcium-containing medium and then to quantify the forces experienced by the attachment during retraction of the PMN at fixed speed. From first touch to final detachment, the typical force history exhibited the following sequence of events: i), an ini...

We introduce a method for the acquisition of single molecule force measurements of ligand-receptor interactions using the photonic force microscope (PFM). Biotin-functionalized beads, manipulated with an optical trap, and a streptavidin-functionalized coverslip were used to measure the effect of different pulling forces on the lifetime of individual streptavidin-biotin complexes. By optimizing ...

DNA secondary structure may prove to be a significant obstacle both for enzymes that process DNA through an orifice and for the passage of DNA through nanopores proposed for some novel sequencing schemes. A nanomechanical molecular "tape reader" is assembled by threading a nanopore over DNA and pulling it using an atomic force microscope. Its formation is confirmed by studying the force require...

Single-molecule force measurement opens a new door for investigating detailed biomolecular interactions and their thermodynamic properties by pulling molecules apart while monitoring the force exerted on them. Recent advances in the nonequilibrium work theorem allows one to determine the free-energy landscapes of these events. Such information is valuable for understanding processes such as pro...

Pushing and pulling equipment in and around the OR can place high shear force demands on perioperative team members' shoulder and back muscles and joints. These high forces may lead to work-related musculoskeletal disorders. AORN Ergonomic Tool 7: Pushing, Pulling, and Moving Equipment on Wheels can help perioperative team members assess the risk of pushing and pulling tasks in the perioperativ...

The results of boxed dynamics (BXD) fully atomistic simulations of protein unfolding by atomic force microscopy (AFM) in both force clamp (FC) and velocity clamp (VC) modes are reported. In AFM experiments the unfolding occurs on a time scale which is too long for standard atomistic molecular dynamics (MD) simulations, which are usually performed with the addition of forces which exceed those o...

Accurate positioning of spindles is essential for asymmetric mitotic and meiotic cell divisions that are crucial for animal development and oocyte maturation, respectively. The predominant model for spindle positioning, termed "cortical pulling," involves attachment of the microtubule-based motor cytoplasmic dynein to the cortex, where it exerts a pulling force on microtubules that extend from ...