Boron (B) is required for cross linking of the pectic polysaccharide rhamnogalacturonan II (RG-II) and is consequently essential for the maintenance of cell wall structure. Arabidopsis (Arabidopsis thaliana) BOR1 is an efflux B transporter for xylem loading of B. Here, we describe the roles of BOR2, the most similar paralog of BOR1. BOR2 encodes an efflux B transporter localized in plasma membrane and is strongly expressed in lateral root caps and epidermis of elongation zones of roots. Transfer DNA insertion of BOR2 reduced root elongation by 68%, whereas the mutation in BOR1 reduced it by 32% under low B availability (0.1 mM), but the reduction in shoot growth was not as obvious as that in the BOR1 mutant. A double mutant of BOR1 and BOR2 exhibited much more severe growth defects in both roots and shoots under B-limited conditions than the corresponding single mutants. All single and double mutants grew normally under B-sufficient conditions. These results suggest that both BOR1 and BOR2 are required under B limitation and that their roles are, at least in part, different. The total B concentrations in roots of BOR2 mutants were not significantly different from those in wild-type plants, but the proportion of cross-linked RG-II was reduced under low B availability. Such a reduction in RG-II cross linking was not evident in roots of the BOR1 mutant. Thus, we propose that under B-limited conditions, transport of boric acid/borate by BOR2 from symplast to apoplast is required for effective cross linking of RG-II in cell wall and root cell elongation.

Thoracic ultrasonography is a simple, sensitive and accurate method for the evaluation of body fluid accumulation in patients with decompensated CHF. This technique can be used to assist in making the diagnosis of decompensated CHF if other causes of pleural effusion have been clinically ruled out.

We have prepared a diluted system of Co3O4 nanocrystals dispersed in nonmagnetic SiO2 by heating an MCM-41 molecular sieve soaked in 0.075 mol/L CoCl2 aqueous solution in flowing oxygen at 300 °C for 3 h. Transmission electron microscopy showed that fine particles of about 3 nm exhibiting the (220) and (331) lattice fringes of the Co3O4 crystal distribute randomly in amorphous SiO2. Magnetic measurements using a SQUID magnetometer suggested the presence of quantum resonant spin tunneling of intraparticle superparamagnetic moments below the blocking temperature. The maximum points in the ac susceptibility shifted toward higher temperature from ≈3 to ≈5 K with increasing the frequency from ≈10-2 to ≈103 Hz. There were no divergent peaks above 1.7 K in the nonlinear susceptibility. The field dependent magnetization from 0 to ≈20 kG showed a small hysteresis loop at 2 K, whereas there were no hysteresis loops at both 5 and 10 K. The diluted Co3O4 nanocrystals is a new and ideally suitable material for the study of macroscopic magnetic quantum effects.

Electronic and magnetic properties of RuSr 2 GdCu 2 O 8 have been investigated by electric resistivity, magnetization, and Cu-, Ru-NMR measurements. Magnetic order (T M ϭ133 K) and superconductivity ͓T s (onset)ϳ52 K͔ have been confirmed. We observed two kinds of Ru-NMR signals ͑the hyperfine fields of 101 Ru are 590 kOe and 290 kOe͒, suggesting a charge segregation of Ru 5ϩ (Sϭ3/2) and Ru 4ϩ (Sϭ1) with complete replacement of the Cu-O chains by Ru-O layers. The RuO 6 octahedra are connected through apical oxygens to two layers of CuO 5 square pyramids. The magnetic order of Ru ions in RuSr 2 RCu 2 O 8 is believed to be associated with the hybridization of Ru-4d and oxygen 2p orbital in the RuO 2 planes, while superconductivity could occur in the CuO 2 planes, if holes are doped inherently into Cu-O 3d-2p orbitals. In this sense, the valence states of Cu and Ru ions are crucial for understanding the origin of ferromagnetism and superconductivity. It is also quite interesting if RuSr 2 RCu 2 O 8 is a particular ferromagnetic superconductor with a high magnetic ordering temperature, as this would suggest a superconducting order parameter of the FuldeFerrell-Larkin-Ovchinnikov type 9 or a possible triplet superconductivity. 4 An interplay between both the order parameters through electromagnetic interactions would produce an exotic state such as a self-induced vortex state, 10 as investigated previously for a magnetic superconductor, Ce 1Ϫx Gd x Ru 2 . 11 Concerning the magnetic nature, the ferromagnetism is still puzzling. Though large magnetic moments would be expected for the ionic state of Ru 5ϩ (Sϭ3/2) or Ru 4ϩ (S ϭ1), an upper limit of the saturated magnetic moments under applied field are obtained to be ϳ1.05 B by the magnetization measurements. 2-4 Moreover, a weak ferromagnetism is observed by the spontaneous magnetization at zero field cooling, and the ferromagnetic component is estimated to be 0.28 B . 2,3 The Ru moments in the ferromagnetic state are suggested to be perpendicular to the c axis by a SR experiment. 3 However, the recent neutron diffraction measurement on RuSr 2 GdCu 2 O 8 ͑Ref. 12͒ demonstrates that the magnetic order of the Ru moments (ϳ1.18 B ) is antiferromagnetic along the c axis in contrast to the conclusion of the ferromagnetic ordering. The ferromagnetic contribution is presumed to be a canting component in the antiferromagnetic arrangements. A recent band calculation 13 supports the lowest energy for an antiferromagnetic arrangement. Thus, the magnetic nature of RuSr 2 RCu 2 O 8 is still controversial.Magnetic order and superconductivity are believed to be mutually exclusive in general. Therefore, a naive question arises: how does the superconducting order parameter develop under the ferromagnetically ordered state with very high T M ? In order to gain insight into the true origin of the coexistence of the magnetism and superconductivity, further extended experiments, especially from a microscopic point of view, are required. Here, we have carried out nuclear magnetic resonance...

To lower the dielectric constant k of interlayer-dielectric films with two-dimensional pore structures while maintaining their mechanical strength, the influences of pore arrangement on the elastic modulus E and k of the films were investigated. It was found that periodicity in pore structure enhances E with constant k. Periodic porous silica films having a hexagonal arrangement of circular cylindrical pores with k < 2:0 and E > 3 GPa were demonstrated to be feasible at a porosity of 0.614 using a bulk material with a k of 4.0 and E > 21 GPa.