53 research outputs found
Low Temperature Anomaly in Mesoscopic Kondo Wires
We report the observation of an anomalous magnetoresistance in extremely
dilute quasi-one-dimensional AuFe wires at low temperatures, along with a
hysteretic background at low fields. The Kondo resistivity does not show the
unitarity limit down to the lowest temperature, implying uncompensated spin
states. We suggest that the anomalous magnetoresistance may be understood as
the interference correction from the accumulation of geometric phase in the
conduction electron wave function around the localized impurity spin.Comment: Four pages, five figure
Possible robust insulator-superconductor transition on solid inert gas and other substrates
We present observations of the insulator-superconductor transition in
ultrathin films of Bi on amorphous quartz, quartz coated with Ge, and for the
first time, solid xenon condensed on quartz. The relative permeability
ranges from 1.5 for Xe to 15 for Ge. Though we find screening
effects as expected, the I-S transition is robust, and unmodified by the
substrate. The resistance separatrix is found to be close to h/4e^2 and the
crossover thickness close to for all substrates. I-V studies and
Aslamazov-Larkin analyses indicate superconductivity is inhomogeneous. The
transition can be understood in terms of a percolation model.Comment: accepted in Physical Review
Purinergic signalling links mechanical breath profile and alveolar mechanics with the pro-inflammatory innate immune response causing ventilation-induced lung injury
Severe pulmonary infection or vigorous cyclic deformation of the alveolar epithelial type I (AT I) cells by mechanical ventilation leads to massive extracellular ATP release. High levels of extracellular ATP saturate the ATP hydrolysis enzymes CD39 and CD73 resulting in persistent high ATP levels despite the conversion to adenosine. Above a certain level, extracellular ATP molecules act as danger-associated molecular patterns (DAMPs) and activate the pro-inflammatory response of the innate immunity through purinergic receptors on the surface of the immune cells. This results in lung tissue inflammation, capillary leakage, interstitial and alveolar oedema and lung injury reducing the production of surfactant by the damaged AT II cells and deactivating the surfactant function by the concomitant extravasated serum proteins through capillary leakage followed by a substantial increase in alveolar surface tension and alveolar collapse. The resulting inhomogeneous ventilation of the lungs is an important mechanism in the development of ventilation-induced lung injury. The high levels of extracellular ATP and the upregulation of ecto-enzymes and soluble enzymes that hydrolyse ATP to adenosine (CD39 and CD73) increase the extracellular adenosine levels that inhibit the innate and adaptive immune responses rendering the host susceptible to infection by invading microorganisms. Moreover, high levels of extracellular adenosine increase the expression, the production and the activation of pro-fibrotic proteins (such as TGF-β, α-SMA, etc.) followed by the establishment of lung fibrosis
Comparison of central and local serial CT assessments of metastatic renal cell carcinoma patients in a clinical phase IIB study
Background: Clinical oncological studies attempt to improve precision of data by central radiological assessments. However, it is unclear, to which extent local and central assessments diverge. Purpose: To quantify inter-reader variability and the deviation of local from central radiological assessments of computed tomography (CT) scans. Material and Methods: This was a sub-study of a randomized clinical phase IIb trial in metastatic renal cell carcinoma (RCC), comparing first-line sorafenib with interferon-alpha-2a (IFN-alpha-2a). It analyzed agreements of local with central RECIST CT assessments by Cohen's kappa (kappa), symmetry tests, deviations in waterfall plots, Bland-Altman plots, and parametric survival analyses. Conclusion: These data suggest that central radiologic review may reduce technical measurement variability in clinical trials, which should be scrutinized in future studies compared to a volumetric reference
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