Symmetry restrictions in chirality dependence of physical properties of single wall nanotubes

We investigate the chirality dependence of physical properties of nanotubes which are wrapped by the planar hexagonal lattice including graphite and boron nitride sheet, and reveal its symmetry origin. The observables under consideration are of scalar, vector and tensor types. These exact chirality dependence obtained are useful to verify the experimental and numerical results and propose accurate empirical formulas. Some important features of physical quantities can also be extracted by only considering the symmetry restrictions without complicated calculations.Comment: 5 pages, 1 figure

Chandra View of DA 530: A Sub-Energetic Supernova Remnant with a Pulsar Wind Nebula?

Based on a Chandra ACIS observation, we report the detection of an extended X-ray feature close to the center of the remnant DA 530 with 5.3 sigma above the background within a circle of 20'' radius. This feature, characterized by a power-law with the photon index gamma=1.6+-0.8 and spatially coinciding with a nonthermal radiosource, most likely represents a pulsar wind nebula. We have further examined the spectrum of the diffuse X-ray emission from the remnant interior with a background-subtracted count rate of ~0.06 counts s^-1 in 0.3-3.5 keV. The spectrum of the emission can be described by a thermal plasma with a temperature of ~0.3-0.6 keV and a Si over-abundance of >~7 solar. These spectral characteristics, together with the extremely low X-ray luminosity, suggest that the remnant arises from a supernova with an anomalously low mechanical energy (<10^50 ergs). The centrally-filled thermal X-ray emission of the remnant may indicate an early thermalization of the SN ejecta by the circum-stellar medium. Our results suggest that the remnant is likely the product of a core-collapsed SN with a progenitor mass of 8-12 Msun. Similar remnants are probably common in the Galaxy, but have rarely been studied.Comment: 23 pages, 7 figures, accepted for publication in ApJ; complete the abstract on astro-ph and correct some typo

The effect of dietary fat intake on hepatic gene expression in LG/J AND SM/J mice

Background The liver plays a major role in regulating metabolic homeostasis and is vital for nutrient metabolism. Identifying the genetic factors regulating these processes could lead to a greater understanding of how liver function responds to a high-fat diet and how that response may influence susceptibilities to obesity and metabolic syndrome. In this study we examine differences in hepatic gene expression between the LG/J and SM/J inbred mouse strains and how gene expression in these strains is affected by high-fat diet. LG/J and SM/J are known to differ in their responses to a high-fat diet for a variety of obesity- and diabetes-related traits, with the SM/J strain exhibiting a stronger phenotypic response to diet. Results Dietary intake had a significant effect on gene expression in both inbred lines. Genes up-regulated by a high-fat diet were involved in biological processes such as lipid and carbohydrate metabolism; protein and amino acid metabolic processes were down regulated on a high-fat diet. A total of 259 unique transcripts exhibited a significant diet-by-strain interaction. These genes tended to be associated with immune function. In addition, genes involved in biochemical processes related to non-alcoholic fatty liver disease (NAFLD) manifested different responses to diet between the two strains. For most of these genes, SM/J had a stronger response to the high-fat diet than LG/J. Conclusions These data show that dietary fat impacts gene expression levels in SM/J relative to LG/J, with SM/J exhibiting a stronger response. This supports previous data showing that SM/J has a stronger phenotypic response to high-fat diet. Based upon these findings, we suggest that SM/J and its cross with the LG/J strain provide a good model for examining non-alcoholic fatty liver disease and its role in metabolic syndrome

Targeted next-generation sequencing of dedifferentiated chondrosarcoma in the skull base reveals combined TP53 and PTEN mutations with increased proliferation index, an implication for pathogenesis

Dedifferentiated chondrosarcoma (DDCS) is a rare disease with a dismal prognosis. DDCS consists of two morphologically distinct components: the cartilaginous and noncartilaginous components. Whether the two components originate from the same progenitor cells has been controversial. Recurrent DDCS commonly displays increased proliferation compared with the primary tumor. However, there is no conclusive explanation for this mechanism. In this paper, we present two DDCSs in the sellar region. Patient 1 exclusively exhibited a noncartilaginous component with a TP53 frameshift mutation in the pathological specimens from the first surgery. The tumor recurred after radiation therapy with an exceedingly increased proliferation index. Targeted next-generation sequencing (NGS) revealed the presence of both a TP53 mutation and a PTEN deletion in the cartilaginous and the noncartilaginous components of the recurrent tumor. Fluorescence in situ hybridization and immunostaining confirmed reduced DNA copy number and protein levels of the PTEN gene as a result of the PTEN deletion. Patient 2 exhibited both cartilaginous and noncartilaginous components in the surgical specimens. Targeted NGS of cells from both components showed neither TP53 nor PTEN mutations, making Patient 2 a naïve TP53 and PTEN control for comparison. In conclusion, additional PTEN loss in the background of the TP53 mutation could be the cause of increased proliferation capacity in the recurrent tumor

Electronic structure and Fermi surface character of LaONiP from first principles

Based on First-principles calculation, we have investigated electronic structure of a ZrCuSiAs structured superconductor LaNiPO. The density of states, band structures and Fermi surfaces have been given in detail. Our results indicate that the bonding of the La-O and Ni-P is strongly covalent whereas binding property between the LaO and NiP blocks is mostly ionic. It's also found that four bands are across the Fermi level and the corresponding Fermi surfaces all have a two-dimensional character. In addition, we also give the band decomposed charge density, which suggests that orbital components of Fermi surfaces are more complicated than cuprate superconductors.Comment: Submitted to Phys.Rev.