The role of rhoA/rho-associated kinase (ROK) signaling pathways in agonist-induced contraction of the rat myometrium was investigated. We measured the [Ca(2+)](i)-force relationship, phosphorylation of myosin regulatory light chains (MLC(20)) in intact tissue and the Ca(2+)-sensitization of force in permeabilized myometrial cells of rat. In measurements of the relationship between [Ca(2+)](i) a...

Sculpting organism shape requires that cells produce forces with proper directionality. Thus, it is critical to understand how cells orient the cytoskeleton to produce forces that deform tissues. During Drosophila gastrulation, actomyosin contraction in ventral cells generates a long, narrow epithelial furrow, termed the ventral furrow, in which actomyosin fibres and tension are directed along ...

DNA is partly denatured in vitro by applying a force that mechanically separates the two strands of the double helix. Sudden reduction of the imposed displacement triggers spontaneous reannealing of the molecule. The corresponding force signals are measured by optical trapping interferometry for backward steps of various amplitudes and base sequence intervals. The measured signals frequently sh...

The sternomastoid (SM) muscle plays an important role in supporting breathing. It also has unique anatomical advantages that allow its wide use in head and neck tissue reconstruction and muscle reinnervation. However, little is known about its contractile properties. The experiments were run on rats and designed to determine in vivo the relationship between muscle force (active muscle contracti...

Skinned fibers from the normal human heart with the beta-myosin heavy chain (ventricular fibers) revealed both a higher force generation per cross section and a higher Ca2+ sensitivity than skinned fibers with the alpha-myosin heavy chain (atrial fibers). The relation between isometric ATPase activity and isometric tension of atrial fibers was higher than that of ventricular fibers. Since the A...

We study the rigidity of two-dimensional site-diluted central force triangular networks under tension. We calculate the shear modulus micro directly and fit it with a power law of the form mu approximately (p-p*)(f), where p is the concentration of sites, p* its critical value, and f the critical exponent. We find that the critical behavior of mu is quite sensitive to tension. As the tension is...

Prestressed concrete (PSC) is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative ind...

To simulate primary atomization, one has to track the position of the phase interface accurately, handle large numbers of topology changes and drops, treat the singular force of surface tension in an accurate and stable manner, and ensure grid-independent numerical results. To address all of these challenges we present a balanced force Refined Level Set Grid (RLSG) method for collocated, unstru...

Skinned fibers from the normal human heart with the f3-myosin heavy chain (ventricular fibers) revealed both a higher force generation per cross section and a higher Ca2' sensitivity than skinned fibers with the a-myosin heavy chain (atrial fibers). The relation between isometric ATPase activity and isometric tension of atrial fibers was higher than that of ventricular fibers. Since the ATPase-...

Faithful distribution of the genome requires that sister kinetochores, which assemble on each chromatid during cell division, interact with dynamic microtubules from opposite spindle poles in a configuration called chromosome biorientation. Biorientation produces tension that increases the affinity of kinetochores for microtubules via ill-defined mechanisms. Non-bioriented kinetochore-microtubu...