We describe a group of alloys that exhibit "super" properties, such as ultralow elastic modulus, ultrahigh strength, super elasticity, and super plasticity, at room temperature and that show Elinvar and Invar behavior. These "super" properties are attributable to a dislocation-free plastic deformation mechanism. In cold-worked alloys, this mechanism forms elastic strain fields of hierarchical structure that range in size from the nanometer scale to several tens of micrometers. The resultant elastic strain energy leads to a number of enhanced material properties.Mechanical properties, such as strength, of metallic materials are strongly affected by metallurgical processes such as heat treatment and plastic working, which bring modifications in the microstructure. On the other hand, these processes have no substantial effect on physical properties such as elastic modulus and thermal expansion. The reason for this is that the changes that can be affected by plastic working and heat treatment do not extend to interatomic bonds or electronic states.We present a group of alloys that exhibit multiple "super" properties and drastic changes in physical properties after plastic working at room temperature. These alloys simultaneously offer super elasticity, super strength, super coldworkability, and Invar and Elinvar properties. The alloys consist of Group IVa and Va elements and oxygen and share the following three electronic magic numbers: (i) a compositional average valence electron number [electron/atom (e/a) ratio] of about 4.24; (ii) a bond order (Bo value) of about 2.87 based on the DV-X␣ cluster method, which represents the bonding strength (1-3); and (iii) a "d" electron-orbital energy level (Md value) of about 2.45 eV, representing electronegativity. The properties emerge only when all three of these magic numbers are satisfied simultaneously. Various alloy composition combinations meet these criteria, such as Ti-12Ta-9Nb-3V-6Zr-O and Ti23Nb-0.7Ta-2Zr-O [mole percent (mol %)], wherein each alloy has a simple body-centered cubic (bcc) crystal structure. In order to exhibit these properties, each alloy system requires substantial cold working and the presence of a certain amount of oxygen, restricted to an oxygen concentration of 0.7 to 3.0 mol %.Typical properties of the alloys are shown in Fig. 1 for samples before and after cold swaging with 90% reduction in area (4). Tensile stress-strain curves shown in Fig. 1A indicate that cold working substantially decreases the elastic modulus and increases the yield strength and confirm nonlinearity in the elastic range, with the gradient of each curve decreasing continuously to about 1/3 its original value near the elastic limit. As a result of this decrease in elastic modulus and nonlinearity, elastic deformability after cold working reaches 2.5%, which is at least double the value before cold working. Generally, large elastic deformations that occur in so-called "super-elastic alloys" are known to be reversible martensitic transformations resulting from deformation, d...

Platelet-activating factor (PAF), a unique phospholipid mediator, possesses potent proinflammatory, smooth-muscle contractile and hypotensive activities, and appears to be crucial in the pathogenesis of bronchial asthma and in the lethality of endotoxin and anaphylactic shock. Despite this, little is known of the molecular properties of the PAF receptor and related signal transduction systems. Although several lines of evidence suggest that activation of the PAF receptor stimulates phospholipase C and subsequent inositol trisphosphate formation through G protein(s), the PAF receptor and calcium channel are reported to show a close relation. As a first approach to cloning lipid autacoid receptors, we have isolated complementary DNA for the PAF receptors. Our strategy involved gene expression in Xenopus laevis oocytes and electrophysiological detection of PAF-induced responses. Sequence analysis indicates that the receptor belongs to the superfamily of G protein-coupled receptors.

Cytoplasmic streaming is active transport widely occurring in plant cells ranging from algae to angiosperms. Although it has been revealed that cytoplasmic streaming is generated by organelle-associated myosin XI moving along actin bundles, the fundamental function in plants remains unclear. We generated high- and low-speed chimeric myosin XI by replacing the motor domains of Arabidopsis thaliana myosin XI-2 with those of Chara corallina myosin XI and Homo sapiens myosin Vb, respectively. Surprisingly, the plant sizes of the transgenic Arabidopsis expressing high- and low-speed chimeric myosin XI-2 were larger and smaller, respectively, than that of the wild-type plant. This size change correlated with acceleration and deceleration, respectively, of cytoplasmic streaming. Our results strongly suggest that cytoplasmic streaming is a key determinant of plant size. Furthermore, because cytoplasmic streaming is a common system for intracellular transport in plants, our system could have applications in artificial size control in plants.

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