3,920 research outputs found
Spin accumulation and decay in magnetic Schottky barriers
The theory of charge and spin transport in forward-biased Schottky barriers reveals characteristic and experimentally relevant features. The conductivity mismatch is found to enhance the current-induced spin imbalance in the semiconductor. The GaAs¿MnAs interface resistance is obtained from an analysis of the magnetic-field-dependent Kerr rotation experiments by Stephens et al. and compared with first-principles calculations for intrinsic interfaces. With increasing current bias, the interface transparency grows toward the theoretical values, reflecting increasingly efficient Schottky barrier screening
Semiclassical Concepts in Magnetoelectronics
Semiclassical theories of electron and spin transport in metallic magnetic
structures are reviewed with emphasis on the role of disorder and electronic
band structures in the current perpendicular to the interface plane (CPP)
transport configuration.Comment: Proceedings of the NEC Symposium on "Spin-related Quantum Transport
in Mesoscopic Systems", to be published in the Journal of Materials Science
and Engineering
Survey of vector-borne agents in feral cats and first report of Babesia gibsoni in cats on St Kitts, West Indies
Background: As there is little data on vector-borne diseases of cats in the Caribbean region and even around the
world, we tested feral cats from St Kitts by PCR to detect infections with Babesia, Ehrlichia and spotted fever group
Rickettsia (SFGR) and surveyed them for antibodies to Rickettsia rickettsii and Ehrlichia canis.
Results: Whole blood was collected from apparently healthy feral cats during spay/ neuter campaigns on St Kitts in
2011 (N = 68) and 2014 (N = 52). Sera from the 52 cats from 2014 were used to detect antibodies to Ehrlichia canis
and Rickettsia rickettsii using indirect fluorescent antibody tests and DNA extracted from whole blood of a total of
119 cats (68 from 2011, and 51 from 2014) was used for PCRs for Babesia, Ehrlichia and Rickettsia. We could not
amplify DNA of SFG Rickettsia in any of the samples but found DNA of E. canis in 5% (6/119), Babesia vogeli in 13%
(15/119), Babesia gibsoni in 4% (5/119), mixed infections with B. gibsoni and B. vogeli in 3% (3/119), and a poorly
characterized Babesia sp. in 1% (1/119). Overall, 10% of the 52 cats we tested by IFA for E. canis were positive while
42% we tested by indirect fluorescent antibody (IFA) for R. rickettsii antigens were positive.
Conclusions: Our study provides the first evidence that cats can be infected with B. gibsoni and also indicates that
cats in the Caribbean may be commonly exposed to other vector-borne agents including SFGR, E. canis and B.
vogeli. Animal health workers should be alerted to the possibility of clinical infections in their patients while public
health workers should be alerted to the possibility that zoonotic SFGR are likely circulating in the region
Aggregating multiple body sensors for analysis in sports
Real time monitoring of the wellness of sportspersons, during their sporting activity and training, is important in order to maximise performance during the sporting event itself and during training, as well as being important for the health of the sportsperson overall. We have combined a suite of common, off-the-shelf sensors with specialist body sensing technology we are developing ourselves and constructed a software system for recording, analysing and presenting sensed data gathered from a single player during a sporting activity, a football match. We gather readings for heart rate, galvanic skin response, motion, heat flux, respiration, and location (GPS) using on-body sensors, while simultaneously tracking player activity using a combination of a playercam video and pitch-wide video recording. We have aggregated all this sensed data into a single overview of player performance and activity which can be reviewed, post-event. We are currently working on integrating other non-invasive methods for real-time on-body monitoring of sweat electrolytes and pH via a textile-based sweat sampling and analysis platform. Our work is heading in two directions; firstly from post-event data aggregation to real-time monitoring, and secondly, to convert raw sensor readings into performance indicators that are meaningful to practitioners in the field
Steady-state solution for dark states using a three-level system in coupled quantum dots
Quantum dots (QDs) are one of the promising candidates of interconnection
between electromagnetic field and electrons in solid-state devices. Dark states
appear as a result of coherence between the electromagnetic fields and the
discrete energy levels of the system. Here, we theoretically solve the
steady-state solutions of the density matrix equations for a thee-level double
QD system and investigate the condition of the appearance of a dark state. We
also numerically show the appearance of the dark state by time-dependent
current characteristics.Comment: 5 pages, 5 figure
The IL-33:ST2 axis is unlikely to play a central fibrogenic role in idiopathic pulmonary fibrosis
BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a devastating interstitial lung disease (ILD) with limited treatment options. Interleukin-33 (IL-33) is proposed to play a role in the development of IPF however the exclusive use of prophylactic dosing regimens means that the therapeutic benefit of targeting this cytokine in IPF is unclear. METHODS: IL-33 expression was assessed in ILD lung sections and human lung fibroblasts (HLFs) by immunohistochemistry and gene/protein expression and responses of HLFs to IL-33 stimulation measured by qPCR. In vivo, the fibrotic potential of IL-33:ST2 signalling was assessed using a murine model of bleomycin (BLM)-induced pulmonary fibrosis and therapeutic dosing with an ST2-Fc fusion protein. Lung and bronchoalveolar lavage fluid were collected for measurement of inflammatory and fibrotic endpoints. Human precision-cut lung slices (PCLS) were stimulated with transforming growth factor-β (TGFβ) or IL-33 and fibrotic readouts assessed. RESULTS: IL-33 was expressed by fibrotic fibroblasts in situ and was increased by TGFβ treatment in vitro. IL-33 treatment of HLFs did not induce IL6, CXCL8, ACTA2 and COL1A1 mRNA expression with these cells found to lack the IL-33 receptor ST2. Similarly, IL-33 stimulation had no effect on ACTA2, COL1A1, FN1 and fibronectin expression by PCLS. Despite having effects on inflammation suggestive of target engagement, therapeutic dosing with the ST2-Fc fusion protein failed to reduce BLM-induced fibrosis measured by hydroxyproline content or Ashcroft score. CONCLUSIONS: Together these findings suggest the IL-33:ST2 axis does not play a central fibrogenic role in the lungs with therapeutic blockade of this pathway unlikely to surpass the current standard of care for IPF
Scattering theory of interface resistance in magnetic multilayers
The scattering theory of transport has to be applied with care in a diffuse
environment. Here we discuss how the scattering matrices of heterointerfaces
can be used to compute interface resistances of dirty magnetic multilayers.
First principles calculations of these interface resistances agree well with
experiments in the CPP (current perpendicular to the interface plane)
configuration.Comment: submitted to J. Phys. D (special issue at the occasion of Prof. T.
Shinjo's 60th birthday
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