89 research outputs found
Why NiAl is an itinerant ferromagnet but NiGa is not
NiAl and NiGa are closely related materials on opposite sides of a
ferromagnetic quantum critical point. The Stoner factor of Ni is virtually the
same in both compounds and the density of states is larger in NiGa. So,
according to the Stoner theory, it should be more magnetic, and, in LDA
calculations, it is. However, experimentally, it is a paramagnet, while
NiAl is an itinerant ferromagnet. We show that the critical spin
fluctuations are stronger than in NiGa, due to a weaker q-dependence of the
susceptibility, and this effect is strong enough to reverse the trend. The
approach combines LDA calculations with the Landau theory and the
fluctuation-dissipation theorem using the same momentum cut-off for both
materials. The calculations provide evidence for strong, beyond LDA, spin
fluctuations associated with the critical point in both materials, but stronger
in NiGa than in NiAl.Comment: replaced (incorrect version submitted
Endothelial Stomatal and Fenestral Diaphragms in Normal Vessels and Angiogenesis
Vascular endothelium lines the entire cardiovascular system where performs a series of vital functions including the control of microvascular permeability, coagulation inflammation, vascular tone as well as the formation of new vessels via vasculogenesis and angiogenesis in normal and disease states. Normal endothelium consists of heterogeneous populations of cells differentiated according to the vascular bed and segment of the vascular tree where they occur. One of the cardinal features is the expression of specific subcellular structures such as plasmalemmal vesicles or caveolae, transendothelial channels, vesiculo-vacuolar organelles, endothelial pockets and fenestrae, whose presence define several endothelial morphological types. A less explored observation is the differential expression of such structures in diverse settings of angiogenesis. This review will focus on the latest developments on the components, structure and function of these specific endothelial structures in normal endothelium as well as in diverse settings of angiogenesis
Über Rubin Laser Schwellenwertuntersuchungen an der Netzhaut.
Wir haben uns die Aufgabe gestellt, Schädigungsschwellenwerte der Retina für Laserstrahlen zu ermitteln. Dabei interessiert hauptsächlich Laserlicht im sichtbaren Specktralbereich, das durch die brechenden Augenmedien auf die Retina fokussiert wird. Dadurch kann an dieser empfindlichsten Stelle eine um ca. 5 Größenordnungen höhere Intensität entstehen.  
ON USING PALLADIUM AND NICKEL-CATALYZED COUPLING REACTIONS FOR THE SYNTHESIS OF POLYAROMATICS - INSIGNIFICANT SIDE REACTIONS CAN MAKE LARGE DIFFERENCES
ON USING PALLADIUM AND NICKEL-CATALYZED COUPLING REACTIONS FOR THE SYNTHESIS OF POLYAROMATICS - INSIGNIFICANT SIDE REACTIONS CAN MAKE LARGE DIFFERENCES
ON USING PALLADIUM AND NICKEL-CATALYZED COUPLING REACTIONS FOR THE SYNTHESIS OF POLYAROMATICS - INSIGNIFICANT SIDE REACTIONS CAN MAKE LARGE DIFFERENCES
Comparative effects of argon green and krypton red laser photocoagulation for patients with diabetic exudative maculopathy.
- …