1,179 research outputs found

    Power cord provided with a power cord transformer

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    A power cord (10) provided with a power cord transformer (12) is described. The transformer comprises a core (11) of ferromagnetic material, a primary coil (13) and a secondary coil (14) both provided around the core. The core and coils have such a shape that the distance between two points on the primary coil and also the distance between two points on the secondary coil is always smaller than twice the largest axis of the power cord cross section

    Decoupling of epitaxial graphene via gold intercalation probed by dispersive Raman spectroscopy

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    Signatures of a superlattice structure composed of a quasi periodic arrangement of atomic gold clusters below an epitaxied graphene (EG) layer are examined using dispersive Raman spectroscopy. The gold-graphene system exhibits a laser excitation energy dependant red shift of the 2D mode as compared to pristine epitaxial graphene. The phonon dispersions in both the systems are mapped using the experimentally observed Raman signatures and a third-nearest neighbour tight binding electronic band structure model. Our results reveal that the observed excitation dependent Raman red shift in gold EG primarily arise from the modifications of the phonon dispersion in gold-graphene and shows that the extent of decoupling of graphene from the underlying SiC substrate can be monitored from the dispersive nature of the Raman 2D modes. The intercalated gold atoms restore the phonon band structure of epitaxial graphene towards free standing graphene

    Remote sensing: Physical principles, sensors and products, and the LANDSAT

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    Techniques of data acquisition by remote sensing are introduced in this teaching aid. The properties of the elements involved (radiant energy, topograph, atmospheric attenuation, surfaces, and sensors) are covered. Radiometers, photography, scanners, and radar are described as well as their products. Aspects of the LANDSAT system examined include the characteristics of the satellite and its orbit, the multispectral band scanner, and the return beam vidicon. Pixels (picture elements), pattern registration, and the characteristics, reception, and processing of LANDSAT imagery are also considered

    Passive heat stress reduces circulating endothelial and platelet microparticles

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    NEW FINDINGS: What is the central question of this study? Does passive heat stress of +2°C oesophageal temperature change concentrations of circulating arterial endothelial- and platelet-derived microparticles in healthy adults? What is the main finding and its importance? Concentrations of circulating endothelial- and platelet-derived microparticles were markedly decreased in heat stress. Reductions in circulating microparticles might indicate favourable vascular changes associated with non-pathological hyperthermia. Interest in circulating endothelial- and platelet-derived microparticles (EMPs and PMPs, respectively) has increased because of their potential pathogenic role in vascular disease and as biomarkers for vascular health. Hyperthermia is commonly associated with a pro-inflammatory stress but might also provide vascular protection when the temperature elevation is non-pathological. Circulating microparticles might contribute to the cellular adjustments and resultant vascular impacts of hyperthermia. Here, we determined whether circulating concentrations of arterial EMPs and PMPs are altered by passive heat stress (+2°C oesophageal temperature). Ten healthy young men (age 23 ± 3 years) completed the study. Hyperthermia was achieved by circulating ∼49°C water through a water-perfused suit that covered the entire body except the hands, feet and head. Arterial (radial) blood samples were obtained immediately before heating (normothermia) and in hyperthermia. The mean ± SD oesophageal temperature in normothermia was 37.2 ± 0.1°C and in hyperthermia 39.1 ± 0.1°C. Concentrations of circulating EMPs and PMPs were markedly decreased in hyperthermia. Activation-derived EMPs were reduced by ∼30% (mean ± SD; from 61 ± 8 to 43 ± 7 microparticles μl-1 ; P < 0.05) and apoptosis-derived EMPs by ∼45% (from 46 ± 7 to 23 ± 3 microparticles μl-1 ; P < 0.05). Likewise, circulating PMPs were reduced by ∼75% in response to hyperthermia (from 256 ± 43 to 62 ± 14 microparticles μl-1 ). These beneficial reductions in circulating EMPs and PMPs in response to a 2°C increase in core temperature might partly underlie the reported vascular improvements following therapeutic bouts of physiological hyperthermia.This study was funded through a Canadian Research Chair and an NSERC Discovery grant held by P.N.A. and a National Institutes of Health award (HL107715 to C.A.D.). A.R.B. is funded through an NSERC postdoctoral fellowship. D.F. is funded through the Swiss National Science Foundation. J.D. is funded by the Woolf Fisher Trust (New Zealand)

    The accuracy of ADC measurements in liver is improved by a tailored and computationally efficient local-rigid registration algorithm

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    This study describes post-processing methodologies to reduce the effects of physiological motion in measurements of apparent diffusion coefficient (ADC) in the liver. The aims of the study are to improve the accuracy of ADC measurements in liver disease to support quantitative clinical characterisation and reduce the number of patients required for sequential studies of disease progression and therapeutic effects. Two motion correction methods are compared, one based on non-rigid registration (NRA) using freely available open source algorithms and the other a local-rigid registration (LRA) specifically designed for use with diffusion weighted magnetic resonance (DW-MR) data. Performance of these methods is evaluated using metrics computed from regional ADC histograms on abdominal image slices from healthy volunteers. While the non-rigid registration method has the advantages of being applicable on the whole volume and in a fully automatic fashion, the local-rigid registration method is faster while maintaining the integrity of the biological structures essential for analysis of tissue heterogeneity. Our findings also indicate that the averaging commonly applied to DW-MR images as part of the acquisition protocol should be avoided if possible

    Prehypertension and Endothelial Progenitor Cell Function.

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    Prehypertension is associated with significant damage to the coronary vasculature and increased rates of adverse cardiovascular events. Circulating endothelial progenitor cells (EPCs) are critical to vascular repair and the formation of new blood vessels. We tested the hypothesis that prehypertension is associated with EPC dysfunction. Peripheral blood samples were collected from 83 middle-aged and older adults (51 M/32 F): 40 normotensive (age 53±2 yr; BP 111/74±1/1 mmHg) and 43 prehypertensive (54±2; 128/77±1/1 mmHg). EPCs were isolated from peripheral blood and EPC colony-forming capacity (colony-forming unit assay), migratory activity (Boyden chamber) and apoptotic susceptibility (active caspase-3 concentrations) were determined. There were no significant differences in either the number of EPC CFUs (10±2 vs. 9±1), EPC migration (1165±82 vs. 1120±84 fluorescent units), or active intracellular caspase-3 concentrations (2.7±0.3 vs. 2.3±0.2 ng/mL) between the normotensive and prehypertensive groups. When groups were stratified into low prehypertension (n=27; systolic BP: 120–129 mmHg) and high prehypertension (n=16; 130–139 mmHg), it was found that EPCs from the high prehypertensive group produced fewer (~65%, P\u3c0.05) CFUs compared with the low prehypertensive (4±1 vs. 12±2) and normotensive adults. In conclusion, EPC colonyforming capacity is impaired only in prehypertensive adults with systolic BP greater than 130 mmHg. Prehypertension is not associated with migratory dysfunction or enhanced apoptosis of EPCs
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