The electronic structure of (C59N)2 from high energy spectroscopy

We report the results of a detailed study of the occupied and unoccupied electronic structure of dimers of the new heterofullerene C59N by means of photoemission and electron energy-loss spectroscopy. A close similarity is found between the electronic structures of pristine (C59N)2 and C60 with an additional broadening of the spectra in the former due to the distortion of the fullerene cage caused both by dimerization and the chemical substitution. Both the occupied and unoccupied electronic states, as well as the interband transitions between them, attest to the high degree of molecular character retained in the solid state. Comparison of the shake-up structures in the C1s and N1s X-ray photo emission spectra confirm that the highest lying occupied states in the heterofullerene have a strong degree of N character, whereas the lowest lying unoccupied states have mainly C character. We also present the optical conductivity of the heterofullerene (derived from the loss function), which shows an optical gap of 1.4 eV, some 0.4 eV smaller than that of C60

The Wave-Front Correction System for the Sunrise Balloon-Borne Solar Observatory

This paper describes the wave-front correction system developed for the Sunrise balloon telescope, and it provides information about its in-flight performance. For the correction of low-order aberrations, a Correlating Wave-Front Sensor (CWS) was used. It consisted of a six-element Shack - Hartmann wave-front sensor (WFS), a fast tip-tilt mirror for the compensation of image motion, and an active telescope secondary mirror for focus correction. The CWS delivered a stabilized image with a precision of 0.04 arcsec (rms), whenever the coarse pointing was better than ± 45 arcsec peak-to-peak. The automatic focus adjustment maintained a focus stability of 0.01 waves in the focal plane of the CWS. During the 5.5 day flight, good image quality and stability were achieved during 33 hours, containing 45 sequences, which lasted between 10 and 45 min. © 2010 The Author(s)

Analysis of ancestral and functionally relevant CD5 variants in systemic lupus erythematosus patients

OBJECTIVE: CD5 plays a crucial role in autoimmunity and is a well-established genetic risk factor of developing RA. Recently, evidence of positive selection has been provided for the CD5 Pro224-Val471 haplotype in East Asian populations. The aim of the present work was to further analyze the functional relevance of non-synonymous CD5 polymorphisms conforming the ancestral and the newly derived haplotypes (Pro224-Ala471 and Pro224-Val471, respectively) as well as to investigate the potential role of CD5 on the development of SLE and/or SLE nephritis. METHODS: The CD5 SNPs rs2241002 (C/T; Pro224Leu) and rs2229177 (C/T; Ala471Val) were genotyped using TaqMan allelic discrimination assays in a total of 1,324 controls and 681 SLE patients of Spanish origin. In vitro analysis of CD3-mediated T cell proliferative and cytokine response profiles of healthy volunteers homozygous for the above mentioned CD5 haplotypes were also analyzed. RESULTS: T-cell proliferation and cytokine release were significantly increased showing a bias towards to a Th2 profile after CD3 cross-linking of peripheral mononuclear cells from healthy individuals homozygous for the ancestral Pro224-Ala471 (CC) haplotype, compared to the more recently derived Pro224-Val471 (CT). The same allelic combination was statistically associated with Lupus nephritis. CONCLUSION: The ancestral Ala471 CD5 allele confers lymphocyte hyper-responsiveness to TCR/CD3 cross-linking and is associated with nephritis in SLE patients

Formation of h

The formation process of hexagonal boron nitride (hBN) monolayer sheets on single-crystalline ZrB2(0001) thin films grown on Si(111) wafers has been investigated by electron diffraction, scanning tunneling microscopy, and photoelectron spectroscopy. A two-step reaction was identified, resulting first in the formation of a silicon nitride layer by room temperature exposure of the silicene-terminated ZrB2 thin film surface to nitrogen radicals and then in the formation of an hBN monolayer replacing the silicon nitride layer through annealing at 900 °C. A large-scale moiré pattern and a clear dispersion of the π-electronic band provide evidence for the formation of an epitaxial hBN monolayer sheet directly on the diboride surface. The unique ability of the ZrB2(0001) surface, upon which both silicene and hBN monolayers can be formed, opens a way toward the integration of these two very different two-dimensional materials

Formation of h BN monolayers through nitridation of epitaxial silicene on diboride thin films

The formation process of hexagonal boron nitride (hBN) monolayer sheets on single-crystalline ZrB2(0001) thin films grown on Si(111) wafers has been investigated by electron diffraction, scanning tunneling microscopy, and photoelectron spectroscopy. A two-step reaction was identified, resulting first in the formation of a silicon nitride layer by room temperature exposure of the silicene-terminated ZrB2 thin film surface to nitrogen radicals and then in the formation of an hBN monolayer replacing the silicon nitride layer through annealing at 900 °C. A large-scale moiré pattern and a clear dispersion of the π-electronic band provide evidence for the formation of an epitaxial hBN monolayer sheet directly on the diboride surface. The unique ability of the ZrB2(0001) surface, upon which both silicene and hBN monolayers can be formed, opens a way toward the integration of these two very different two-dimensional materials