Phytase, an enzyme that degrades the phosphorus storage compound phytate, has the potential to enhance phosphorus availability in animal diets when engineered into soybean (Glycine max) seeds. The phytase gene from Aspergillus niger was inserted into soybean transformation plasmids under control of constitutive and seed-specific promoters, with and without a plant signal sequence. Suspension cultures were used to confirm phytase expression in soybean cells. Phytase mRNA was observed in cultures containing constitutively expressed constructs. Phytase activity was detected in the culture medium from transformants that received constructs containing the plant signal sequence, confirming expectations that the protein would follow the default secretory pathway. Secretion also facilitated characterization of the biochemical properties of recombinant phytase. Soybean-synthesized phytase had a lower molecular mass than did the fungal enzyme. However, deglycosylation of the recombinant and fungal phytase yielded polypeptides of identical molecular mass (49 kD). Temperature and pH optima of the recombinant phytase were indistinguishable from the commercially available fungal phytase. Thermal inactivation studies of the recombinant phytase suggested that the additional protein stability would be required to withstand the elevated temperatures involved in soybean processing.

A geometrically exact curved/ twisted beam theory, that assumes that the beam cross-section remains rigid, is re-examined and extended using orthonormal frames of reference starting from a 3-D beam theory. The relevant engineering strain measures with an initial curvature correction term at any material point on the current beam cross-section, that are conjugate to the first PiolaKirchhoff stresses, are obtained through the deformation gradient tensor of the current beam configuration relative to the initially curved beam configuration. The stress resultant and couple are defined in the classical sense and the reduced strains are obtained from the three-dimensional beam model, which are the same as obtained from the reduced differential equations of motion. The reduced differential equations of motion are also re-examined for the initially curved/twisted beams. The corresponding equations of motion include additional inertia terms as compared to previous studies. The linear and linearized nonlinear constitutive relations with couplings are considered for the engineering strain and stress conjugate pair at the three-dimensional beam level. The cross-section elasticity constants corresponding to the reduced constitutive relations are obtained with the initial curvature correction term. Along with the beam theory, some basic concepts associated with finite rotations are also summarized in a manner that is easy to understand.

We report neutron diffuse scattering measurements on highly magnetostrictive Fe 1Àx Ga x alloys (0:14 < x < 0:20) with different thermal treatments. This diffuse scattering scales with magnetostriction and exhibits asymmetric peaks at the (100) and (300) reciprocal lattice positions that are consistent with the coexistence of short-range ordered, coherent nanometer-scale precipitates embedded in a long-range ordered, body-centered cubic matrix. A large peak splitting is observed at (300) for x ¼ 0:19, which indicates that the nanoprecipitates are not cubic and have a large elastic strain. This implies a structural origin for the enhanced magnetostriction. DOI: 10.1103/PhysRevLett.102.127201 PACS numbers: 75.80.+q, 61.05.fg, 64.70.Nd, 75.50.Bb Mechanically strong and malleable Galfenol alloys (Fe 1Àx Ga x ) exhibit enhanced and extremely large magnetostriction coefficients along [100] of up to 3 100 =2 ¼ 400 ppm at low saturation fields [1,2]. The addition of Ga into the body-centered cubic (bcc) -Fe phase is known to produce a diversity of crystal structures including chemically disordered bcc A2 (Fe), ordered bcc DO 3 (Fe 3 Ga), ordered bcc B 2 (FeGa), and face-centered cubic L1 2 (Fe 3 Ga) phases [3,4]. Previous studies of Fe 1Àx Ga x alloys cooled (postgrowth) at 10 C= min have shown the presence of two anomalous peaks in the magnetostriction. The first peak at x % 0:19 has been attributed to an increase in the magnetoelastic coupling, resulting from the formation of short-range ordered (SRO) Ga pairs along the [100] axis of the A2 structure [5], and the second at x % 0:27 to a softening of the shear modulus c 0 ¼ ðc 11 -c 12 Þ=2 [6,7]. Of special note is the fact that both 3 100 =2 and the presence of a two-phase region (A2 þ DO 3 ) depend sensitively on thermal history; this suggests that the enhanced magnetostriction is due to an underlying heterogeneity rather than a conventional homogeneous ferromagnetic phase.A structurally heterogeneous model [8] has been proposed to explain the enhanced magnetostriction and elastic softening for such Fe 1Àx Ga x alloys. This model assumes that the heat treatment produces a structurally and chemically heterogeneous state consisting of coarseningresistant, nanometer-scale DO 3 precipitates within an A2 matrix. Theoretically, heterogeneity has been predicted to result from the following sequence of transformations: (i) bcc ! bcc 0 þ DO 3 decomposition, followed by (ii) a diffusionless Bain strain that transforms the DO 3 nanoprecipitates into a face-centered tetragonal (fct) structure. Recently, nanometer-scale (<2 nm) DO 3 precipitates [9] have been identified in an A2 matrix of Fe 0:81 Ga 0:19 using high-resolution transmission electron microscopy (HRTEM), consistent with the theoretical prediction of step (i) in the transformational sequence. However, all prior structural investigations have shown that both the DO 3 and A2 phases are cubic. There have been no reports of lower-symmetry phases, as predicted by step (ii) in the transformational sequence. This is a ke...

We characterized the magnetomechanical conversion abilities of Ni-Zn ferrite, cobalt ferrite, and Metglas by constructing a magnetic power path with two winding coils. We found that under high power drive, a portion of the mechanical power re-transformed to the magnetic form and was captured by the receiver coil, which resulted in a decrease in the magnetomechanical conversion ability of the coil-magnetostriction structure. This presents an upper limit of the power conversion characteristics of magnetoelectric gyrators. Furthermore, the efficiency of a Metglas/Pb(Zr,Ti)O3 gyrator was characterized by varying the values of the resistive load, magnetic bias, and power density. The maximum measured efficiency for the power transferred across an optimal resistor load was greater than 90% under low drive conditions and 89% with a power density of up to 30 W/in.3

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