Iron Regulation of Hepcidin Despite Attenuated Smad1,5,8 Signaling in Mice Without Transferrin Receptor 2 or Hfe.

BACKGROUND & AIMS: HFE and transferrin receptor 2 (TFR2) are each necessary for the normal relationship between body iron status and liver hepcidin expression. In murine Hfe and Tfr2 knockout models of hereditary hemochromatosis (HH), signal transduction to hepcidin via the bone morphogenetic protein 6 (Bmp6)/Smad1,5,8 pathway is attenuated. We examined the effect of dietary iron on regulation of hepcidin expression via the Bmp6/Smad1,5,8 pathway using mice with targeted disruption of Tfr2, Hfe, or both genes. METHODS: Hepatic iron concentrations and messenger RNA expression of Bmp6 and hepcidin were compared with wild-type mice in each of the HH models on standard or iron-loading diets. Liver phospho-Smad (P-Smad) 1,5,8 and Id1 messenger RNA levels were measured as markers of Bmp/Smad signaling. RESULTS: Whereas Bmp6 expression was increased, liver hepcidin and Id1 expression were decreased in each of the HH models compared with wild-type mice. Each of the HH models also showed attenuated P-Smad1,5,8 levels relative to liver iron status. Mice with combined Hfe/Tfr2 disruption were most affected. Dietary iron loading increased hepcidin and Id1 expression in each of the HH models. Compared with wild-type mice, HH mice demonstrated attenuated (Hfe knockout) or no increases in P-Smad1,5,8 levels in response to dietary iron loading. CONCLUSIONS: These observations show that Tfr2 and Hfe are each required for normal signaling of iron status to hepcidin via the Bmp6/Smad1,5,8 pathway. Mice with combined loss of Hfe and Tfr2 up-regulate hepcidin in response to dietary iron loading without increases in liver Bmp6 messenger RNA or steady-state P-Smad1,5,8 levels

Structure and properties of a novel fulleride Sm6C60

A novel fulleride Sm6C60 has been synthesized using high temperature solid state reaction. The Rietveld refinement on high resolution synchrotron X-ray powder diffraction data shows that Sm6C60 is isostructural with body-centered cubic A6C60 (A=K, Ba). Raman spectrum of Sm6C60 is similar to that of Ba6C60, and the frequencies of two Ag modes in Sm6C60 are nearly the same as that of Ba6C60, suggesting that Sm is divalent and hybridization between C60 molecules and the Sm atom could exist in Sm6C60. Resistivity measurement shows a weak T-linear behavior above 180 K, the transport at low temperature is mainly dominated by granular-metal theory.Comment: 9 pages, 3 figures, submitted to Phys. Rev. B (March 12, 1999

Optical investigation of the charge-density-wave phase transitions in NbSe3NbSe_{3}

We have measured the optical reflectivity $R(\omega)$ of the quasi one-dimensional conductor $NbSe_{3}$ from the far infrared up to the ultraviolet between 10 and 300 $K$ using light polarized along and normal to the chain axis. We find a depletion of the optical conductivity with decreasing temperature for both polarizations in the mid to far-infrared region. This leads to a redistribution of spectral weight from low to high energies due to partial gapping of the Fermi surface below the charge-density-wave transitions at 145 K and 59 K. We deduce the bulk magnitudes of the CDW gaps and discuss the scattering of ungapped free charge carriers and the role of fluctuations effects

X-Ray Scattering Measurements of the Transient Structure of a Driven Charge-Density-Wave

We report time-resolved x-ray scattering measurements of the transient structural response of the sliding {\bf Q}$_{1}$ charge-density-wave (CDW) in NbSe$_{3}$ to a reversal of the driving electric field. The observed time scale characterizing this response at 70K varies from $\sim$ 15 msec for driving fields near threshold to $\sim$ 2 msec for fields well above threshold. The position and time-dependent strain of the CDW is analyzed in terms of a phenomenological equation of motion for the phase of the CDW order parameter. The value of the damping constant, $\gamma = (3.2 \pm 0.7) \times 10^{-19}$ eV $\cdot$ seconds $\cdot$ \AA$^{-3}$, is in excellent agreement with the value determined from transport measurements. As the driving field approaches threshold from above, the line shape becomes bimodal, suggesting that the CDW does not depin throughout the entire sample at one well-defined voltage.Comment: revtex 3.0, 7 figure

Innovation and HRM : absences and politics

This article analyses the role of HRM practices in the implementation of an innovative cross-functional approach to new product development (concurrent engineering, CE) in Eurotech Industries. Contrary to CE methodology stipulations, and despite supportive conditions, HRM received scant attention in the implementation process. Organizational power and politics were clearly involved in this situation, and this article explores how their play created such HRM &lsquo;absences&rsquo;. The article builds on a four-dimensional view of power in order to provide a deeper understanding of the embedded, interdependent and political nature of HRM practice and innovation.<br /

Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

Formation of stars and planets: the role of magnetic fields

Star formation is thought to be triggered by gravitational collapse of the dense cores of molecular clouds. Angular momentum conservation during the collapse results in the progressive increase of the centrifugal force, which eventually halts the inflow of material and leads to the development of a central mass surrounded by a disc. In the presence of an angular momentum transport mechanism, mass accretion onto the central object proceeds through this disc, and it is believed that this is how stars typically gain most of their mass. However, the mechanisms responsible for this transport of angular momentum are not well understood. Although the gravitational field of a companion star or even gravitational instabilities (particularly in massive discs) may play a role, the most general mechanisms are turbulence viscosity driven by the magnetorotational instability (MRI), and outflows accelerated centrifugally from the surfaces of the disc. Both processes are powered by the action of magnetic fields and are, in turn, likely to strongly affect the structure, dynamics, evolutionary path and planet-forming capabilities of their host discs. The weak ionisation of protostellar discs, however, may prevent the magnetic field from effectively coupling to the gas and shear and driving these processes. Here I examine the viability and properties of these magnetically-driven processes in protostellar discs. The results indicate that, despite the weak ionisation, the magnetic field is able to couple to the gas and shear for fluid conditions thought to be satisfied over a wide range of radii in these discs.Comment: Invited Review. 11 figures and 1 table. Accepted for publication in Astrophysics & Space Scienc

Masculinities, affect and the (re)place(ment) of stardom in Formula One fan leisure practices

Writing from an autoethnographic perspective, this article explores male leisure practices via the mediated relationships fans enter into with stars. More specifically, my own fandom for Formula One driver Jacques Villeneuve is the locus of study, revealing how this affective investment shapes and furnishes my corresponding leisure practices. Notions of gendered 'performativity' come to the fore, with my own displays evoking, enacting and revealing oscillating performances of masculinity. Moreover, there are interesting gendered dynamics that such fan leisure practices flag in terms of the intersection of female/male relationships and the potential 'fantasy' and/or narcissistic readings that a male fan identifying with and performing as another male sport star afford. Finally, my research reveals paradoxes for contemporary masculinities, with fans reliant upon mediation and commodification to facilitate and sustain their performative roles. © 2011 Taylor & Francis