445 research outputs found
Josephson Junctions with a synthetic antiferromagnetic interlayer
We report measurements of the critical current vs. Co thickness in
Nb/Cu/Co/Ru/Co/Cu/Nb Josephson junctions, where the inner Co/Ru/Co trilayer is
a "synthetic antiferromagnet" with the magnetizations of the two Co layers
coupled antiparallel to each other via the 0.6 nm-thick Ru layer. Due to the
antiparallel magnetization alignment, the net intrinsic magnetic flux in the
junction is nearly zero, and such junctions exhibit excellent Fraunhofer
patterns in the critical current vs. applied magnetic field, even with total Co
thicknesses as large as 23 nm. There are no apparent oscillations in the
critical current vs. Co thickness, consistent with theoretical expectations for
this situation. The critical current of the junctions decays over 4 orders of
magnitude as the total Co thickness increases from 3 to 23 nm. These junctions
may serve as useful templates for future explorations of spin-triplet
superconducting correlations, which are predicted to occur in supercon-
ducting/ferromagnetic hybrid systems in the presence of certain types of
magnetic inhomogeneity.Comment: 4 pages, 5 figure
Vessel Cold-Ironing Using a Barge Mounted PEM Fuel Cell: Project Scoping and Feasibility.
A barge-mounted hydrogen-fueled proton exchange membrane (PEM) fuel cell system has the potential to reduce emissions and fossil fuel use of maritime vessels in and around ports. This study determines the technical feasibility of this concept and examines specific options on the U.S. West Coast for deployment practicality and potential for commercialization.The conceptual design of the system is found to be straightforward and technically feasible in several configurations corresponding to various power levels and run times.The most technically viable and commercially attractive deployment options were found to be powering container ships at berth at the Port of Tacoma and/or Seattle, powering tugs at anchorage near the Port of Oakland, and powering refrigerated containers on-board Hawaiian inter-island transport barges. Other attractive demonstration options were found at the Port of Seattle, the Suisun Bay Reserve Fleet, the California Maritime Academy, and an excursion vessel on the Ohio River
Pifithrin-alpha inhibits p53 signaling after interaction of the tumor suppressor protein with hsp90 and its nuclear translocation
Pifithrin-alpha (PFTalpha) was originally thought to be a specific inhibitor of signaling by the tumor suppressor protein p53. However, the laboratory that discovered pifithrin recently reported that the compound also inhibits heat shock and glucocorticoid receptor (GR) signaling, and they suggested that PFTalpha targets a factor common to all three signal transduction pathways, such as the hsp90/hsp70-based chaperone machinery (Komarova, E. A., Neznanov, N., Komarov, P. G., Chernov, M. V., Wang, K., and Gudkov, A. V. (2003) J. Biol. Chem. 278, 15465-15468). Because it is important for the mechanistic study of this machinery to identify unique inhibitors of chaperone action, we have examined the effect of PFTalpha on transcriptional activation, the hsp90 heterocomplex assembly, and hsp90-dependent nuclear translocation for both p53 and the GR. At concentrations where PFTalpha blocks p53-mediated induction of p21/Waf-1 in human embryonic kidney cells, we observed no inhibition of GR-mediated induction of a chloramphenicol acetyl transferase reporter in LMCAT cells. PFTalpha did, however, cause a left shift in the dexamethasone dose response curve by increasing intracellular dexamethasone concentration, apparently by competing for dexamethasone efflux from the cell. The assembly of p53 or GR heterocomplexes with hsp90 and immunophilins was not affected by PFTalpha either in vivo or in vitro and did not affect the nuclear translocation of either transcription factor. Thus, we conclude that PFTalpha does not inhibit GR-mediated induction or the function of the chaperone machinery, and, as originally thought, it may specifically inhibit p53 signaling by acting at a stage after p53 translocation to the nucleus.Fil: Murphy, Patrick J.. University of Michigan; Estados UnidosFil: Galigniana, Mario Daniel. University of Michigan; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Morishima, Yoshihiro. University of Michigan; Estados UnidosFil: Harrell, Jennifer M.. University of Michigan; Estados UnidosFil: Kwok, Roland P.. University of Michigan; Estados UnidosFil: Ljungman, Mats. University of Michigan; Estados UnidosFil: Pratt, William B.. University of Michigan; Estados Unido
Spin-Diffusion Lengths in Metals and Alloys, and Spin-Flipping at Metal/Metal Interfaces: an Experimentalist's Critical Review
In magnetoresistive (MR) studies of magnetic multilayers composed of
combinations of ferromagnetic (F) and non-magnetic (N) metals, the magnetic
moment (or related 'spin') of each conduction electron plays a crucial role,
supplementary to that of its charge. While initial analyses of MR in such
multilayers assumed that the direction of the spin of each electron stayed
fixed as the electron transited the multilayer, we now know that this is true
only in a certain limit. Generally, the spins 'flip' in a distance
characteristic of the metal, its purity, and the temperature. They can also
flip at F/N or N1/N2 interfaces. In this review we describe how to measure the
lengths over which electron moments flip in pure metals and alloys, and the
probability of spin-flipping at metallic interfaces. Spin-flipping within
metals is described by a spin-diffusion length,l^M(sf), where the metal M = F
or N. Spin-diffusion lengths are the characteristic lengths in the
current-perpendicular-to-plane (CPP) and lateral non-local (LNL) geometries
that we focus upon in this review. In certain simple cases, l^N(sf) sets the
distance over which the CPP-MR and LNL-MR decrease as the N-layer thickness
(CPP-MR) or N-film length (LNL) increases, and l^F(sf) does the same for
increase of the CPP-MR with increasing F-layer thickness. Spin-flipping at
M1/M2 interfaces can be described by a parameter, delta(M1/M2), which
determines the spin-flipping probability, P = 1 - exp(-delta). Increasing
delta(M1/M2) usually decreases the MR. We list measured values of these
parameters and discuss the limitations on their determinations.Comment: Invited Review, to appear in J. Phys. Cond. Matter. 50 pages, 18
figures. The new version contains additional material and revisions to
improve clarit
Bostonia: The Boston University Alumni Magazine. Volume 10
Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs
Development of a decision support tool to facilitate primary care management of patients with abnormal liver function tests without clinically apparent liver disease [HTA03/38/02]. Abnormal Liver Function Investigations Evaluation (ALFIE)
Liver function tests (LFTs) are routinely performed in primary care, and are often the gateway to further invasive and/or expensive investigations. Little is known of the consequences in people with an initial abnormal liver function (ALF) test in primary care and with no obvious liver disease. Further investigations may be dangerous for the patient and expensive for Health Services. The aims of this study are to determine the natural history of abnormalities in LFTs before overt liver disease presents in the population and identify those who require minimal further investigations with the potential for reduction in NHS costs
Recommended from our members
Mainstreaming domestic and gender-based violence into sociology and the criminology of violence
Sociological and criminological views of domestic and gender-based violencegenerally either dismiss it as not worthy of consideration, or focus on specificgroups of offenders and victims (male youth gangs, partner violence victims). Inthis paper, we take a holistic approach to violence, extending the definition fromthat commonly in use to encompass domestic violence and sexual violence. Weoperationalize that definition by using data from the latest sweep of the CrimeSurvey for England and Wales. By so doing, we identify that violence is currentlyunder-measured and ubiquitous; that it is gendered, and that other forms of violence (family violence, acquaintance violence against women) are equally ofconcern. We argue that violence studies are an important form of activity forsociologists
- …