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At least 50% of the actin in resting human platelets is unpolymerized, and the bulk of this unpolymerized actin is complexed with a recently identified acidic, heat-stable 5-kDa peptide, named "Fx." Purified Fx binds stoichiometrically to muscle G-actin, forming a complex identifiable by nondenaturing polyacrylamide gel electrophoresis. Formation of the(More)
Avoiding predators is an essential behavior in which animals must quickly transform sensory cues into evasive actions. Sensory reflexes are particularly fast in flying insects such as flies, but the means by which they evade aerial predators is not known. Using high-speed videography and automated tracking of flies in combination with aerodynamic(More)
Primary cultures of rat dorsal root ganglionic (DRG) cells were stained with isoform-specific antibodies against non-muscle myosin II. Antibodies against the brain type myosin (MIIB) stained the peripheries of growth cones and non-neuronal cells. Double staining of the cells with the anti-myosin antibodies and rhodamine-phalloidin or anti-actin antibodies(More)
Myosin light chains from normal and hypertrophied human hearts were partially sequenced in order to see whether structural modifications of these light subunits could provide a molecular basis for the changes observed in heart properties and in myosin enzymatic activity. Normal light chains were prepared form hearts taken at autopsy, weighing 350 g or less(More)
In closed-loop systems, sensor feedback delays may have disastrous implications for performance and stability. Flies have evolved multiple specializations to reduce this latency, but the fastest feedback during flight involves a delay that is still significant on the timescale of body dynamics. We explored the effect of sensor delay on flight stability and(More)
The flight pattern of many fly species consists of straight flight segments interspersed with rapid turns called body saccades, a strategy that is thought to minimize motion blur. We analyzed the body saccades of fruit flies (Drosophila hydei), using high-speed 3D videography to track body and wing kinematics and a dynamically scaled robot to study the(More)
This paper discusses the inertia tensors of tennis rackets and their influence on the elbow swing torques in a forehand motion, the loadings transmitted to the elbow from central and eccentric impacts, and the racket acceleration responses from central and eccentric impacts. Inertia tensors of various rackets with similar mass and mass center location were(More)
The amino acid sequences of selected cyanogen bromide peptides from human blood platelet actin and human cardiac muscle actin were compared; it was found that, at position 129, platelet actin has threonine, and that cardiac muscle actin has valine. Thus human cytoplasmic and myofibrillar actins must be synthesized under the control of different genes.
The ability to regulate forward speed is an essential requirement for flying animals. Here, we use a dynamically-scaled robot to study how flapping insects adjust their wing kinematics to regulate and stabilize forward flight. The results suggest that the steady-state lift and thrust requirements at different speeds may be accomplished with quite subtle(More)
Using high-speed videography, we investigated how fruit flies compensate for unilateral wing damage, in which loss of area on one wing compromises both weight support and roll torque equilibrium. Our results show that flies control for unilateral damage by rolling their body towards the damaged wing and by adjusting the kinematics of both the intact and(More)
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