Sheet Dependence on Superconducting Gap in Oxygen-Deficient Iron-based Oxypnictide Superconductors NdFeAs0.85

Photoemission spectroscopy with low-energy tunable photons on oxygen-deficient iron-based oxypnictide superconductors NdFeAsO0.85 (Tc=52K) reveals a distinct photon-energy dependence of the electronic structure near the Fermi level (EF). A clear shift of the leading-edge can be observed in the superconducting states with 9.5 eV photons, while a clear Fermi cutoff with little leading-edge shift can be observed with 6.0 eV photons. The results are indicative of the superconducting gap opening not on the hole-like ones around Gamma (0,0) point but on the electron-like sheets around M(pi,pi) point.Comment: 8 pages, 3 figure

Symptomatic Developmental Venous Anomaly with an Increased β2-microglobulin Level in Cerebrospinal Fluid: A Case Report

Background: Gadolinium-enhanced magnetic resonance imaging (MRI) can be used to observe the progression of cerebral infarction, which sometimes mimics malignant brain tumors. While the β2-microglobulin (β2MG) level in blood plasma or cerebrospinal fluid (CSF) is useful for the diagnosis of malignant tumors or degenerative diseases, these results may create confusion regarding a definitive diagnosis, because it is not a specific marker. We present a rare case of symptomatic developmental venous anomaly (DVA), accompanied by transient, irregular, enhanced cerebral lesions and elevated β2MG in the CSF. Case Description: A 56-year-old woman developed dysarthria and underwent MRI, which revealed a right frontal hyperintense area around a previous lesion on diffusion-weighted imaging (DWI). She was treated based on the tentative diagnosis of an ischemic cerebrovascular event, and symptoms subsided in 3 days. MRI on day 7 revealed an enlargement of the hyperintense area on DWI. Post-gadolinium MRI showed multiple, enhanced patchy areas in the right frontal lobe and an abnormally large vein connected to dilated medullary venules, indicating DVA. Magnetic resonance angiography showed no stenosis or arterial occlusion. The β2MG level in the CSF was elevated at 2,061 μg/l, and a differential diagnosis from malignant tumor was required. However, MRI on day 23 revealed total disappearance of the enhanced lesions and a decrease in the high intensity area on DWI. Considering the clinical course, the DVA was symptomatic because of the perfusion disturbance. Conclusion: Careful evaluation is necessary when considering the associated pathologies and potential complications of DVA if detected near a gadolinium-enhanced lesion

Structure of MSPL–inhibitor complex

Infection of certain influenza viruses is triggered when its HA is cleaved by host cell proteases such as proprotein convertases and type II transmembrane serine proteases (TTSP). HA with a monobasic motif is cleaved by trypsin-like proteases, including TMPRSS2 and HAT, whereas the multibasic motif found in high pathogenicity avian influenza HA is cleaved by furin, PC5/6, or MSPL. MSPL belongs to the TMPRSS family and preferentially cleaves [R/K]-K-K-R↓ sequences. Here, we solved the crystal structure of the extracellular region of human MSPL in complex with an irreversible substrate-analog inhibitor. The structure revealed three domains clustered around the C-terminal α-helix of the SPD. The inhibitor structure and its putative model show that the P1-Arg inserts into the S1 pocket, whereas the P2-Lys and P4-Arg interacts with the Asp/Glu-rich 99-loop that is unique to MSPL. Based on the structure of MSPL, we also constructed a homology model of TMPRSS2, which is essential for the activation of the SARS-CoV-2 spike protein and infection. The model may provide the structural insight for the drug development for COVID-19

Topological surface states of ternary chalcogenides probed by ARPES

Trabajo presentado a la "16th International Conference on Solid Films and Surfaces" celebrada en Genova (Italia) del 1 al 6 de julio de 2012.Three-dimensional topological insulators (3D TIs) recently emerge as a new state of quantum matter, which can be topologically classified with Z2 topological invariants. It possesses a massless Dirac Fermion in a bulk energy gap whose spin orientations are locked with electron momentum, resulting in a helical spin texture. A number of 3D TIs have been intensively studied, among which Bi2Se3 has been regarded as one of the most promising candidates for potential applications in ultra-low power consumption quantum devices that can work stably at room temperature due to a sufficiently large bulk energy gap. Therefore, a significant effort has been made towards spintronic applications, but the surface contribution to conduction was hardly observed. This stimulates us to search for new 3D TIs possessing more ideal Dirac Fermions sufficiently isolated from the bulk continuum as actually predicted in several ternary compounds. Here we have studied the surface Dirac cones of several ternary chalcogenides including TlBiSe2 and PbBi2Te4 by high-resolution angle resolved photoemission spectroscopy using synchrotron radiation at Hiroshima Synchrotron Radiation Center (HiSOR). The single topological surface state is confirmed to be present at the surface Brillouin zone (SBZ) center for TlBiSe2. The Dirac cone is practically ideal especially near the Dirac point and its velocity is larger than for Bi2Se3. There are no bulk continuum states that energetically overlap with the DP, which means that the scattering channel from the topological surface state to the bulk continuum is suppressed. We have also clarified that PbBi2Te4 is the 3D TI, accompanying a single Dirac cone at the SBZ center. The size of the Fermi surface contours are significantly large in the bulk energy gap region. Besides, this material is found to have a Z2 topological invariant 1; (111). These novel findings pave an effective way for controlling the group velocity with sufficiently large spin current density by tuning the chemical potential in the topological quantum transport regionPeer Reviewe

Group IIA secreted phospholipase A2 controls skin carcinogenesis and psoriasis by shaping the gut microbiota

Besides promoting inflammation by mobilizing lipid mediators, group IIA secreted phospholipase A2 (sPLA2-IIA) prevents bacterial infection by degrading bacterial membranes. Here, we show that, despite the restricted intestinal expression of sPLA2-IIA in BALB/c mice, its genetic deletion leads to amelioration of cancer and exacerbation of psoriasis in distal skin. Intestinal expression of sPLA2-IIA is reduced after treatment with antibiotics or under germ-free conditions, suggesting its upregulation by gut microbiota. Metagenome, transcriptome, and metabolome analyses have revealed that sPLA2-IIA deficiency alters the gut microbiota, accompanied by notable changes in the intestinal expression of genes related to immunity and metabolism, as well as in the levels of various blood metabolites and fecal bacterial lipids, suggesting that sPLA2-IIA contributes to shaping of the gut microbiota. The skin phenotypes in Pla2g2a–/– mice are lost (a) when they are cohoused with littermate WT mice, resulting in the mixing of the microbiota between the genotypes, or (b) when they are housed in a more stringent pathogen-free facility, where Pla2g2a expression in WT mice is low and the gut microbial compositions in both genotypes are nearly identical. Thus, our results highlight a potentially new aspect of sPLA2-IIA as a modulator of gut microbiota, perturbation of which affects distal skin responses

Solitary Cranial Langerhans Cell Histiocytosis : Two case reports

Langerhans cell histiocytosis (LCH) is a proliferation of Langerhans cells intermixed with inflammatory cells, in particular eosinophils, that may manifest as a unisystem (unifocal or multifocal) or multisystem disease. We describe the clinical and histologic spectrum of LCH of the orbit and skull in our two cases. Both cases had unifocal erosive skull lesions with a history of trauma. Typical histologic features included numerous histiocytes with varying degrees of giant cell formation and scattered eosinophilic granulocytes. The presence of Langerhans cells was confirmed by CD1a and S100 immunohistochemistry. LCH has an excellent prognosis when treated with surgical resection, steroids and radiotherapy or chemotherapy. One of our patients is disease free at 7 year follow-up and one patient had regression of lesion on follow-up