1,888 research outputs found
Logarithmic singularities and quantum oscillations in magnetically doped topological insulators
We report magnetotransport measurements on magnetically doped
(Bi,Sb)Te films grown by molecular beam epitaxy. In Hallbar devices,
logarithmic dependence on temperature and bias voltage are obseved in both the
longitudinal and anomalous Hall resistance. The interplay of disorder and
electron-electron interactions is found to explain quantitatively the observed
logarithmic singularities and is a dominant scattering mechanism in these
samples. Submicron scale devices exhibit intriguing quantum oscillations at
high magnetic fields with dependence on bias voltage. The observed quantum
oscillations can be attributed to bulk and surface transport.Comment: 10 pages, 13 figure
Plastic Deformation Modes of CuZr/ Cu Multilayers
We synthesized CuZr/Cu multilayers and performed nanoindentation testing to explore the dependence of plastic deformation modes on the thickness of CuZr layers. The Cu layers were 18 nm thick and the CuZr layers varied in thickness from 4 nm to 100 nm. We observed continuous plastic co-deformation in the 4 nm and 10 nm CuZr − 18 nm Cu multilayers and plastic-induced shear instability in thick CuZr layers (\u3e20 nm). The plastic co-deformation is ascribed to the nucleation and interaction of shear transformation zones in CuZr layers at the adjacent interfaces, while the shear instability is associated with the nucleation and propagation of shear bands in CuZr layers. Shear bands are initialized in the CuZr layers due to the accumulated glide dislocations along CuZr-Cu interfaces, and propagate into adjacent Cu layers via slips on {111} plane non-parallel to the interface. Due to crystallographic constraint of the Cu layers, shear bands are approximately parallel to {111} plane in the Cu layer
Investigation of the oxidation mechanisms of superlattice Cr-CrN/TiSiN-Cr multilayer coatings on Zircaloy substrates under high-temperature steam atmospheres
Identification and Nearly Full-Length Genome Characterization of Novel Porcine Bocaviruses
The genus bocavirus includes bovine parvovirus (BPV), minute virus of canines (MVC), and a group of human bocaviruses (HBoV1-4). Using sequence-independent single primer amplification (SISPA), a novel bocavirus group was discovered with high prevalence (12.59%) in piglet stool samples. Two nearly full-length genome sequences were obtained, which were approximately 5,100 nucleotides in length. Multiple alignments revealed that they share 28.7–56.8% DNA sequence identity with other members of Parvovirinae. Phylogenetic analyses indicated their closest neighbors were members of the genus bocavirus. The new viruses had a putative non-structural NP1 protein, which was unique to bocaviruses. They were provisionally named porcine bocavirus 1 and 2 (PBoV1, PBoV2). PBoV1 and PBoV2 shared 94.2% nucleotide identity in NS1 gene sequence, suggesting that they represented two different bocavirus species. Two additional samples (6V, 7V) were amplified for 2,407 bp and 2,434 bp products, respectively, including a partial NP1 gene and the complete VP1 gene; Phylogenetic analysis indicated that 6Vand 7V grouped with PBoV1 and PBoV2 in the genus of bocavirus, but were in the separate clusters. Like other parvoviruses, PBoV1, PBoV2, 6Vand 7V also contained a putative secretory phospholipase A2 (sPLA2) motif in the VP1 unique region, with a conserved HDXXY motif in the catalytic center. The conserved motif YXGXF of the Ca2+-binding loop of sPLA2 identified in human bocavirus was also found in porcine bocavirus, which differs from the YXGXG motif carried by most other parvoviruses. The observation of PBoV and potentially other new bocavirus genus members may aid in molecular and functional characterization of the genus bocavirus
Identification of the Cylindromatosis Tumor-Suppressor Gene Responsible for Multiple Familial Trichoepithelioma
Multiple familial trichoepithelioma (MFT) is an autosomal dominant skin disease characterized by the presence of many small benign tumors with pilar differentiation predominantly on the face. The first locus has been previously mapped to chromosome 9p21, but no gene for MFT has been identified to date. To identify the disease gene in a large Chinese family, we initially performed linkage analysis with microsatellite markers from 9p21, but failed to confirm the linkage to this region. Previous publications showed MFT and familial cylindromatosis (FC) can occur within one family and in a single person. Therefore, we speculated that the cylindromatosis gene (CYLDI gene) responsible for FC may be related to the pathogenesis of MFT. In view of that, we genotyped all available individuals using 11 microsatellite markers spanning the CYLDI gene region at 16q12–q13. We identified the linkage of MFT to this region. Mutation analysis in the CYLDI gene detected a frameshift mutation, designated as c.2355–2358delCAGA. The study firstly identified the cylindromatosis gene responsible for MFT and showed that different mutations of the CYLDI gene can give rise to distinct clinical and histological expression such as FC and MFT
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Photo-functionalized TiO2 nanotubes decorated with multifunctional Ag nanoparticles for enhanced vascular biocompatibility
Titanium dioxide (TiO2) has a long history of application in blood contact materials, but it often suffers from insufficient anticoagulant properties. Recently, we have revealed the photocatalytic effect of TiO2 also induces anticoagulant properties. However, for long-term vascular implant devices such as vascular stents, besides anticoagulation, also anti-inflammatory, anti-hyperplastic properties, and the ability to support endothelial repair, are desired. To meet these requirements, here, we immobilized silver nanoparticles (AgNPs) on the surface of TiO2 nanotubes (TiO2-NTs) to obtain a composite material with enhanced photo-induced anticoagulant property and improvement of the other requested properties. The photo-functionalized TiO2-NTs showed protein-fouling resistance, causing the anticoagulant property and the ability to suppress cell adhesion. The immobilized AgNPs increased the photocatalytic activity of TiO2-NTs to enhances its photo-induced anticoagulant property. The AgNP density was optimized to endow the TiO2-NTs with anti-inflammatory property, a strong inhibitory effect on smooth muscle cells (SMCs), and low toxicity to endothelial cells (ECs). The in vivo test indicated that the photofunctionalized composite material achieved outstanding biocompatibility in vasculature via the synergy of photo-functionalized TiO2-NTs and the multifunctional AgNPs, and therefore has enormous potential in the field of cardiovascular implant devices. Our research could be a useful reference for further designing of multifunctional TiO2 materials with high vascular biocompatibility
Cordyceps Sinensis: anti-fibrotic and inflammatory effects of a cultured polysaccharide extract
It has been suggested that the traditional Chinese herbal preparation Cordyceps Sinensis (CS) may have a beneficial effect in renal disease. To satisfy increasing demand, CS derivatives have been produced by aseptic mycelia cultivation. We have demonstrated antifibrotic activity of cultured CS previously. The aim of this study was to examine bioactivity of a polysaccharide isolated from cultured CS with a complicated monosaccharide composition, mainly consisting of Gal, Glc and Man. This polysaccharide antagonised the effect of TGF-b1 in stimulating the expression of collagen in the HK2 renal cell line. This was associated with down regulation of the TGF-b receptor Alk5. In addition the polysaccharide antagonised IL-1b stimulated sICAM-1 dependent adherence of monocytes to a monolayer of HK2 cell. This was associated with increased expression of the primary receptor for hyaluronan CD44, and was abrogated by removal of the cell surface hyaluronan pericellular coat. In summary we describe both anti-fibrotic and anti-inflammatory activity in a polysaccharide isolated from cultured CS
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