333 research outputs found

    Why Ni3_3Al is an itinerant ferromagnet but Ni3_3Ga is not

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    Ni3_3Al and Ni3_3Ga 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 Ni3_3Ga. So, according to the Stoner theory, it should be more magnetic, and, in LDA calculations, it is. However, experimentally, it is a paramagnet, while Ni3_3Al is an itinerant ferromagnet. We show that the critical spin fluctuations are stronger than in Ni3_3Ga, 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 Ni3_3Ga than in Ni3_3Al.Comment: replaced (incorrect version submitted

    An emerging role for IQGAP1 in tight junction control

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    © 2016, © 2016 The Author(s). Published with license by Taylor & Francis. © 2016, © Barbara E. Tanos, Charles Yeaman, and Enrique Rodriguez-Boulan. IQGAP1 is a scaffold protein involved in the assembly of adherens junctions. Our work has recently revealed a novel role for IQGAP1 in the regulation of tight junctions (TJ) through differential recruitment of claudins to the nascent TJ. Here, we discuss the potential mechanisms of this regulation, including IQGAP1 effects on CDC42, and IQGAP1 interactions with sorting/trafficking molecules (e.g. Exo70). Given the many roles of IQGAP1 and the large number of interacting partners, we focus our discussion of these functions in the context of junction formation, trafficking, growth factor signaling and cancer. We also propose a potential role for IQGAP1 in regulating epithelial integrity and compartmentalized signaling in epithelia

    Vitrectomy with complete posterior hyaloid removal for ischemic central retinal vein occlusion: Series of cases

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    BACKGROUND: Central retinal vein occlusion (CRVO) is a common retinal vascular disorder with potentially complications: (1) persistent macular edema and (2) neovascular glaucoma. No safe treatment exists that promotes the return of lost vision. Eyes with CRVO may be predisposed to vitreous degeneration. It has been suggested that if the vitreous remains attached to the macula owing to a firm vitreomacular adhesion, the resultant vitreous traction can cause inflammation with retinal capillary dilation, leakage and subsequent edema6. The roll of vitrectomy in ischemic CRVO surgical procedures has not been evaluated. CASE PRESENTATION: This is a non comparative, prospective, longitudinal, experimental and descriptive series of cases. Ten eyes with ischemic CRVO. Vitrectomy with complete posterior hyaloid removal was performed. VA, rubeosis, intraocular pressure (IOP), and macular edema were evaluated clinically. Multifocal ERG (m-ERG), fluorescein angiography (FAG) and optic coherence tomography (OCT) were performed. Follow-up was at least 6 months. Moderate improvement of visual acuity was observed in 60% eyes and stabilized in 40%. IOP changed from 15.7 ± 3.05 mmHg to 14.9 ± 2.69 mmHg post-operative and macular edema from 976 ± 196 μm to 640 ± 191 μm to six month. The P1 wave amplitude changed from 25.46 ± 12.4 mV to 20.54 ± 11.2 mV. CONCLUSION: A solo PPV with posterior hyaloid removal may help to improve anatomic and functional retina conditions in some cases. These results should be considered when analyzing other surgical maneuvers

    Endothelial Stomatal and Fenestral Diaphragms in Normal Vessels and Angiogenesis

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    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

    Latest results from the SEMATECH Berkeley extreme ultraviolet microfield exposure tool

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    Microfield exposure tools (METs) continue to play a dominant role in the development of extreme ultraviolet (EUV) resists. One of these tools is the 0.3 numerical aperture SEMATECH Berkeley MET operating as a resist and mask test center. Here they present an update on the tool summarizing some of the latest test and characterization results. they provide an update on the long-term aberration stability of the tool and present line-space imaging in chemically amplified photoresist down to the 20-nm half-pitch level. Although resist development has shown substantial progress in the area of resolution, line-edge-roughness (LER) remains a significant concern. Here we present a summary of recent LER performance results and consider the effect of mask contributors to the LER observed from the SEMATECH Berkeley microfield tool
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