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Phase equilibria of [Fe.sub.2][O.sub.3] have been studied up to 58 GPa and 1400 K using the Kawai-type multi anvil apparatus equipped with sintered diamond anvils. Identification of phases and pressure determination has been carried out by means of in situ X-ray observation using synchrotron radiation at SPring-8. Hematite (phase I) successively transforms to the [Rh.sub.2][O.sub.3](II)-type structure (phase II) and then to an orthorhombic structure (phase III) with increasing pressure. The transformations of hematite into high-pressure phases have been observed only at temperatures higher than 500 K, which is not concordant with previous results obtained by using the diamond anvil cell. Volume changes accompanied by the I-II and II-III transformations are calculated to be -2.8 and -5.0%, respectively. The phase boundary between I and II phases and that between II and III have been proposed to be P (GPa) = -0.015 T (K) + 44.2 and P (GPa) = -0.005 T (K) + 48.7, respectively. Possible correlation between a Mort transition and the phase stabilities may be concealed at room temperature due to slow reaction kinetics of the structural transformations. Keywords: High-pressure phase equilibria, [Fe.sub.3][O.sub.3], Kawai-cell, sintered diamond, in situ X-ray observation

The pressure-volume equation of state (EoS) of single-crystal MgO has been studied in diamond-anvil cells loaded with helium to 118 GPa and in a non-hydrostatic KC1 pressure medium to 87 GPa using monochromatic synchrotron X-ray diffraction. A third-order Birch-Murnaghan fit to the non-hydrostatic P-V data (KC1 medium) yields typical results for the initial volume, [V.sub.0] = 74.698(7) [[Angstrom].sup.3], bulk modulus, [K.sub.T0] = 164(1) GPa, and pressure derivative, K' = 4.05(4), using the non-hydrostatic ruby pressure gauge of Mao et al. (1978). However, compression of MgO in helium yields [V.sub.0] = 74.697(6) [[Angstrom].sup.3], [K.sub.T0] = 159.6(6) GPa, and K' = 3.74(3) using the quasi-hydrostatic ruby gauge of Mao et al. (1986). In helium, the fitted equation of state of MgO underdetermines the pressure by 8% at 100 GPa when compared with the primary MgO pressure scale of Zha et al. (2000), with [K.sub.T0] = 160.2 GPa and K' = 4.03. The results suggest that either the compression mechanism of MgO changes above 40 GPa (in helium), or the ruby pressure gauge requires adjustment for the softer helium pressure medium. We propose a ruby pressure gauge for helium based on shift of the ruby-[R.sub.1] fluorescence line ([DELTA][LAMBDA]/[[LAMBDA].sub.0]) and the primary MgO pressure scale, with P (GPa) = A/B{[[1 + ([DELTA][LAMBDAP]/[[LAMBDA].sub.0]).sup.B] - 1}, where A is fixed to 1904 GPa and B = 10.32(7). Keywords: MgO, helium pressure medium, static compression, equation of state, ruby fluorescence

We have measured Raman spectra of the postperovskite (PPv) phase in CaIr[O.sub.3] up to 30 GPa to constrain the Gruneisen parameter ([gamma]). We identified a total of 4 strong modes between 200 and 650 [cm.sup.-1], which is in contrast with the Raman spectra of [Mn.sub.2][O.sub.3] and MgGe[O.sub.3]-PPv where at least nine different modes have been detected. We found no sign of a phase transition in the Raman spectra of PPv CaIr[O.sub.3], which supports the stability of the PPv phase up to 30 GPa and room temperature in CaIr[O.sub.3]. The spectroscopic Gruneisen parameter, [[gamma].sub.sp.0] = 1.66~1.72, constrained from our Raman data, is in excellent agreement with the thermodynamic Gruneisen parameter, [[gamma].sub.th,0] = 1.75 [+ or -] 0.05, calculated from recent XRD measurements (Martin et al. 2007) on CaIr[O.sub.3]-PPv synthesized at high pressure and temperature similar to our starting material. Our result suggests that [[gamma].sub.sp] constrained by Raman measurements provides a reasonable estimate on the [[gamma].sub.th] of the PPv phase in CaIr[O.sub.3]. Keywords: Postperovskite, CaIr[O.sub.3], Gruneisen parameter, Raman sepctroscopy, thermal equation of state

Chronic hypoxia accelerates renal fibrosis. The chief mediator of the hypoxic response is hypoxia-inducible factor 1 (HIF-1) and its oxygen-sensitive component HIF-1[alpha]. HIF-1 regulates a wide variety of genes, some of which are closely associated with tissue fibrosis. To determine the specific role of HIF-1 in renal fibrosis, we generated a knockout mouse in which tubular epithelial expression of von Hippel-Lindau tumor suppressor (VHL), which acts as a ubiquitin ligase to promote proteolysis of HIF-1[alpha], was targeted. We investigated the effect of VHL deletion (i.e., stable expression of HIF-1[alpha]) histologically and used the anti-HIF-1[alpha] agent [3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole] (YC-1) to test whether inhibition of HIF-1[alpha] could represent a novel approach to treating renal fibrosis. The area of renal fibrosis was significantly increased in a 5/6 renal ablation model of [VHL.sup.-/-] mice and in all VH[L.sup.-/-] mice at least 60 wk of age. Injection of YC-1 inhibited the progression of renal fibrosis in unilateral ureteral obstruction model mice. In conclusion, HIF-1[alpha] appears to be a critical contributor to the progression of renal fibrosis and could be a useful target for its treatment. hypoxia; HIF-1; VHL; fibrosis; fibroblast-specific protein 1

Using the CaIr[O.sub.3]-type structure model (space group Cmcm), lattice parameters and atomic positions of the MgGe[O.sub.3] post-perovskite (pPv) phase were determined based on Rietveld refinements at 78-109 GPa and first-principles calculations based on density functional theory. The reproducibility of structural parameters obtained for different samples, consistency with theoretical calculations, and good agreement with expected bond lengths based on structurally similar materials all provide evidence for both validity of CaIr[O.sub.3]-type structure model for the pPv phase in MgGe[O.sub.3] exceeding 1 Mbar and reliability of structural parameters obtained by Rietveld refinements approaching 1 Mbar. The MgGe[O.sub.3] pPv phase exhibits strong anisotropy in axial compressibility, with the b-axis being most compressible. The polyhedral bulk modulus for the Ge[O.sub.6] octahedron is 1.9x larger than that for the Mg[O.sub.8] hendecahedron. Examination of neighboring O-O distances shows that the O-O distance aligned along the a direction is one of the longest and that aligned along c is one of the shortest, and these may be related to the lower compressibility along e compared with a. Comparison of structural features of MgGe[O.sub.3] pPv with those for MgSi[O.sub.3], NaMg[F.sub.3], and CaIr[O.sub.3] pPv show that MgSi[O.sub.3] pPv has more similarity with NaMg[F.sub.3] and MgGe[O.sub.3] pPv than with CaIr[O.sub.3] pPv in such parameters as degree of octahedral distortion, implying that both NaMg[F.sub.3] and MgGe[O.sub.3] pPv are better analogs to MgSi[O.sub.3] pPv than CaIr[O.sub.3] pPv. Keywords: Post-perovskite, MgGe[O.sub.3], Rietveld refinement, high-pressure experiment, first-principles calculation, laser-heated diamond anvil cell, density functional theory, polycrystalline X-ray diffraction

Intriguing seismic observations have been made for the bottom 400 km of Earth's mantle (the D' region) over the past few decades, yet the origin of these seismic structures has not been well understood. Recent theoretical calculations have predicted many unusual changes in physical properties across the postperovskite transition, perovskite (Pv) [right arrow] postperovskite (PPv), that may provide explanations for the seismic observations. Here, we report measurements of the crystal structure of ([Mg.sub.0.91][Fe.0.09])Si[O.sub.3]-PPv under quasi-hydrostatic conditions up to the pressure (P)-temperature (7) conditions expected for the core-mantle boundary (CMB). The measured crystal structure is in excellent agreement with the first-principles calculations. We found that bulk sound speed ([V.sub.[PHI]) decreases by 2.4 [+ or -] 1.4% across the PPv transition. Combined with the predicted shear-wave velocity ([V.sub.s]) increase, our measurements indicate that lateral variations in mineralogy between Pv and PPv may result in the anticorrelation between the [V.sub.[PHI] and Vs anomalies at the D' region. Also, density increases by 1.6 [+ or -] 0.4% and Gruneisen parameter decreases by 21 [+ or -] 15% across the PPv transition, which will dynamically stabilize the PPv lenses observed in recent seismic studies. equation of state | mantle | phase transition | bulk sound speed | Gruneisen parameter

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2006.01.024 Byline: Kyoko Miwata, Takuto Chiba, Reiko Horii, Lixy Yamada, Atsushi Kubo, Daisuke Miyamura, Nori Satoh, Yutaka Satou Keywords: Ciona intestinalis; Ascidian; Zinc finger; Expression profile Abstract: The recent decoding of a number of animal genomes has provided unprecedented information regarding evolution and gene structures, but this information must be supplemented with precise gene annotations and the temporal and spatial expression patterns of individual genes. In the present study, we systematically identified and characterized 566 zinc finger genes in the genome of Ciona intestinalis, an emerging model system for genome-wide studies of development and evolution. Of these genes, 356 genes encoded a potential transcription factor based on putative nucleic acid binding activity or domains of unknown function. We further examined the expression patterns of 225 genes during embryogenesis, and, when considered with a previous study [Imai, K.S., Hino, K., Yagi, K., Satoh, N., Satou, Y., 2004. Gene expression profiles of transcription factors and signaling molecules in the ascidian embryo: towards a comprehensive understanding of gene networks. Development 131, 4047-4058], we have characterized the developmental expression patterns of nearly 85% of the potential zinc finger-containing transcription factors. Overall, zinc finger genes are preferentially maternally expressed with little larval expression during development. The present study provides a valuable reference for genome-wide studies in this species and for future studies wishing to examine zinc finger gene expression patterns in other animals. Author Affiliation: Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan Article History: Received 30 September 2005; Revised 20 January 2006; Accepted 21 January 2006

Using the laser-heated diamond anvil cell, we investigate the stability and equation of state of the postperovskite (ppv, Calr[O.sub.3]type) phase synthesized from a natural pyroxene composition with 9 mol.% FeSi[O.sub.3]. Our measured pressure-volume data from 12-106 GPa for the ppv phase yield a bulk modulus of 219(5) GPa and a zero-pressure volume of 164.9(6) [[Angstrom].sup.3] when [K'.sub.0] = 4. The bulk modulus of ppv is 575(15) GPa at a pressure of 100 GPa. The transition pressure is lowered by the presence of Fe. Our x-ray diffraction data indicate the ppv phase can be formed at P > 109(4) GPa and 2,400(400) K, corresponding to [approximately equal to] 400-550 km above the core-mantle boundary. Direct comparison of volumes of coexisting perovskite and Calr[O.sub.3]-type phases at 80-106 GPa demonstrates that the ppv phase has a smaller volume than perovskite by 1.1(2)%. Using measured volumes together with the bulk modulus calculated from equation of state fits, we find that the bulk sound velocity decreases by 2.3(2.1)% across this transition at 120 GPa. Upon decompression without further heating, it was found that the ppv phase could still be observed at pressures as low at 12 GPa, and evidence for at least partial persistence to ambient conditions is also reported. phase transition | x-ray diffraction | high pressure | diamond anvil cell | lower mantle