High Quality a-axis outgrowth on c-axis YlCa1-xBa2Cu3O7-d

The large amplitude of the high Tc (HTS) superconducting gap is attractive for improved electronic applications. However, the study of such HTS cuprates has uncovered that unlike the s-wave order parameter of the low Tc, an angle dependent dx2-y2 wave function is the dominant order parameter in such compounds. This symmetry causes low energy surface bound states, detrimental for applications, except at (100) oriented surfaces. It is therefore essential to have a smooth and well oriented surface of the crystallographic a-axis (100). In this work we present a study of an unconventional way to attain such surfaces in the form of a-axis outgrowth on a c-axis surface of sputtered Y1-xCaxBa2Cu3O7-d thin film. The grains topography was tested using X-ray, SEM and AFM together with Point Contact and Tunnel Junctions measurements.Comment: 15 pages, 5 figure

Determination of the critical current density in the d-wave superconductor YBCO under applied magnetic fields by nodal tunneling

We have studied nodal tunneling into YBa2Cu3O7-x (YBCO) films under magnetic fields. The films' orientation was such that the CuO2 planes were perpendicular to the surface with the a and b axis at 450 form the normal. The magnetic field was applied parallel to the surface and perpendicular to the CuO2 planes. The Zero Bias Conductance Peak (ZBCP) characteristic of nodal tunneling splits under the effect of surface currents produced by the applied fields. Measuring this splitting under different field conditions, zero field cooled and field cooled, reveals that these currents have different origins. By comparing the field cooled ZBCP splitting to that taken in decreasing fields we deduce a value of the Bean critical current superfluid velocity, and calculate a Bean critical current density of up to 3*10^7 A/cm2 at low temperatures. This tunneling method for the determination of critical currents under magnetic fields has serious advantages over the conventional one, as it avoids having to make high current contacts to the sample.Comment: 8 pages, 2 figure

Cutaneous lesions of the nose

Skin diseases on the nose are seen in a variety of medical disciplines. Dermatologists, otorhinolaryngologists, general practitioners and general plastic and dermatologic surgeons are regularly consulted regarding cutaneous lesions on the nose. This article is the second part of a review series dealing with cutaneous lesions on the head and face, which are frequently seen in daily practice by a dermatologic surgeon. In this review, we focus on those skin diseases on the nose where surgery or laser therapy is considered a possible treatment option or that can be surgically evaluated

The spectrum of spinal cord lesions in a primate model of multiple sclerosis

International audienceBackground: Experimental autoimmune encephalomyelitis (EAE) in the common marmoset is a nonhuman primate model of multiple sclerosis (MS) that shares numerous clinical, radiological, and pathological features with MS. Among the clinical features are motor and sensory deficits that are highly suggestive of spinal cord (SC) damage.Objective: To characterize the extent and nature of SC damage in symptomatic marmosets with EAE using a combined magnetic resonance imaging (MRI) and histopathology approach.Materials and methods: SC tissues from five animals were scanned using 7 T MRI to collect high-resolution ex vivo images. Lesions were segmented and classified based on shape, size, and distribution along the SC. Tissues were processed for histopathological characterization (myelin and microglia/macrophages). Statistical analysis, using linear mixed-effects models, evaluated the association between MRI and histopathology.Results: Marmosets with EAE displayed two types of SC lesions: focal and subpial lesions. Both lesion types were heterogeneous in size and configuration and corresponded to areas of marked demyelination with high density of inflammatory cells. Inside the lesions, the MRI signal was significantly correlated with myelin content (p < 0.001).Conclusions: Our findings underscore the relevance of this nonhuman primate EAE model for better understanding mechanisms of MS lesion formation in the SC

Herpesvirus trigger accelerates neuroinflammation in a nonhuman primate model of multiple sclerosis.

Pathogens, particularly human herpesviruses (HHVs), are implicated as triggers of disease onset/progression in multiple sclerosis (MS) and other neuroinflammatory disorders. However, the time between viral acquisition in childhood and disease onset in adulthood complicates the study of this association. Using nonhuman primates, we demonstrate that intranasal inoculations with HHV-6A and HHV-6B accelerate an MS-like neuroinflammatory disease, experimental autoimmune encephalomyelitis (EAE). Although animals inoculated intranasally with HHV-6 (virus/EAE marmosets) were asymptomatic, they exhibited significantly accelerated clinical EAE compared with control animals. Expansion of a proinflammatory CD8 subset correlated with post-EAE survival in virus/EAE marmosets, suggesting that a peripheral (viral?) antigen-driven expansion may have occurred post-EAE induction. HHV-6 viral antigen in virus/EAE marmosets was markedly elevated and concentrated in brain lesions, similar to previously reported localizations of HHV-6 in MS brain lesions. Collectively, we demonstrate that asymptomatic intranasal viral acquisition accelerates subsequent neuroinflammation in a nonhuman primate model of MS