Electronic Structure of the Chevrel-Phase Compounds Snx_{x}Mo6_{6}Se7.5_{7.5}: Photoemission Spectroscopy and Band-structure Calculations

We have studied the electronic structure of two Chevrel-phase compounds, Mo$_6$Se$_{7.5}$ and Sn$_{1.2}$Mo$_6$Se$_{7.5}$, by combining photoemission spectroscopy and band-structure calculations. Core-level spectra taken with x-ray photoemission spectroscopy show systematic core-level shifts, which do not obey a simple rigid-band model. The inverse photoemission spectra imply the existence of an energy gap located $\sim 1$ eV above the Fermi level, which is a characteristic feature of the electronic structure of the Chevrel compounds. Quantitative comparison between the photoemission spectra and the band-structure calculations have been made. While good agreement between theory and experiment in the wide energy range was obtained as already reported in previous studies, we found that the high density of states near the Fermi level predicted theoretically due to the Van Hove singularity is considerably reduced in the experimental spectra taken with higher energy resolution than in the previous reports. Possible origins are proposed to explain this observation.Comment: 8 pages, 5 figure

Canonical Quantization of SU(3) Skyrme Model in a General Representation

A complete canonical quantization of the SU(3) Skyrme model performed in the collective coordinate formalism in general irreducible representations. In the case of SU(3) the model differs qualitatively in different representations. The Wess-Zumino-Witten term vanishes in all self-adjoint representations in the collective coordinate method for separation of space and time variables. The canonical quantization generates representation dependent quantum mass corrections, which can stabilize the soliton solution. The standard symmetry breaking mass term, which in general leads to representation mixing, degenerates to the SU(2) form in all self-adjoint representations.Comment: 24 RevTex4 pages, no figure

Hall-effect and resistivity measurements in CdTe and ZnTe at high pressure: Electronic structure of impurities in the zincblende phase and the semi-metallic or metallic character of the high-pressure phases

We carried out high-pressure resistivity and Hall-effect measurements in single crystals of CdTe and ZnTe up to 12 GPa. Slight changes of transport parameters in the zincblende phase of CdTe are consitent with the shallow character of donor impurities. Drastic changes in all the transport parameters of CdTe were found around 4 GPa, i.e. close to the onset of the cinnabar to rock-salt transition. In particular, the carrier concentration increases by more than five orders of magnitude. Additionally, an abrupt decrease of the resistivity was detected around 10 GPa. These results are discussed in comparison with optical, thermoelectric, and x-ray diffraction experiments. The metallic character of the Cmcm phase of CdTe is confirmed and a semi-metallic character is determined for the rock-salt phase. In zincblende ZnTe, the increase of the hole concentration by more than two orders of magnitude is proposed to be due to a deep-to-shallow transformation of the acceptor levels. Between 9 and 11 GPa, transport parameters are consistent with the semiconducting character of cinnabar ZnTe. A two orders of magnitude decrease of the resistivity and a carrier-type inversion occurs at 11 GPa, in agreement with the onset of the transition to the Cmcm phase of ZnTe. A metallic character for this phase is deduced.Comment: 20 pages, 4 figure

Plane-wave based electronic structure calculations for correlated materials using dynamical mean-field theory and projected local orbitals

The description of realistic strongly correlated systems has recently advanced through the combination of density functional theory in the local density approximation (LDA) and dynamical mean field theory (DMFT). This LDA+DMFT method is able to treat both strongly correlated insulators and metals. Several interfaces between LDA and DMFT have been used, such as (N-th order) Linear Muffin Tin Orbitals or Maximally localized Wannier Functions. Such schemes are however either complex in use or additional simplifications are often performed (i.e., the atomic sphere approximation). We present an alternative implementation of LDA+DMFT, which keeps the precision of the Wannier implementation, but which is lighter. It relies on the projection of localized orbitals onto a restricted set of Kohn-Sham states to define the correlated subspace. The method is implemented within the Projector Augmented Wave (PAW) and within the Mixed Basis Pseudopotential (MBPP) frameworks. This opens the way to electronic structure calculations within LDA+DMFT for more complex structures with the precision of an all-electron method. We present an application to two correlated systems, namely SrVO3 and beta-NiS (a charge-transfer material), including ligand states in the basis-set. The results are compared to calculations done with Maximally Localized Wannier functions, and the physical features appearing in the orbitally resolved spectral functions are discussed.Comment: 15 pages, 17 figure

Dynamic architectural interplay between leucocytes and mammary epithelial cells.

The adult mammary gland undergoes dynamic changes during puberty and the postnatal developmental cycle. The mammary epithelium is composed of a bilayer of outer basal, or myoepithelial, cells and inner luminal cells, the latter lineage giving rise to the milk-producing alveolar cells during pregnancy. These luminal alveolar cells undergo Stat3-mediated programmed cell death following the cessation of lactation. It is established that immune cells in the microenvironment of the gland have a role to play both in the ductal outgrowth during puberty and in the removal of dead cells and remodelling of the stroma during the process of postlactational regression. However, most studies have focussed on the role of the stromal immune cell compartment or have quantified immune cell populations in tissue extracts. Our recent development of protocols for deep imaging of the mammary gland in three dimensions (3D) has enabled the architectural relationship between immune cells and the epithelium to be examined in detail, and we have discovered a surprisingly dynamic relationship between the basal epithelium and leucocytes. Furthermore, we have observed morphological changes in the myoepithelial cells, as involution progresses, which were not revealed by previous work in 2D tissue sections and whole tissue. This dynamic architecture suggests a role for myoepithelial cells in the orderly progression of involution. We conclude that deep imaging of mammary gland and other tissues is essential for analysing complex interactions between cellular compartments

Spinal Cord Injury Repair by Intrathecal Infusion of Stromal Cell-Derived Factor-1/CXC Chemokine Receptor 4 in a Rat Model

Background: Stromal cell-derived factor-1 (SDF-1)/CXC Chemokine receptor 4 (CXCR4) is an important cytokine, with multiple functions, which plays a crucial role in the recruitment of multiple stem cell types in the defect sites of central nervous system (CNS). Various strategies have been managed to improve functional recovery after spinal cord injury (SCI). One of these strategies is the use of factors to limit damage and increase recovery. Objectives: In this study we investigated the effect of SDF-1 in spinal cord injury repair in a rat model. Materials andMethods: Adult male Wistar rats were randomly divided to four groups (n = 5) as follows: Sham, SCI, SDF-1 and Vehicle. Spinal cord injury model was created by contusion of T8-T9 by clips and SDF-1 infusion pump implanted in the neck region. One week after injury, 5-Bromo-20-Deoxyuridine (BrdU) was injected to trace the proliferative cells. Basso-Beattie-Bresnahan (BBB) test was performed to evaluate locomotor activity following SCI. Immunohistochemistry test was performed to determine proliferating cells, and real time polymerase chain reaction (PCR) was performed to detect the CXCR4 cells in tissue. Results: Significant improvements in locomotor function were detected in the SDF-1 group compared with the SCI and vehicle groups (P < 0.05). The results showed that SDF-1 treatment increased proliferative cells at the spinal cord injury site. Real time PCR revealed that these proliferative cells are CXCR4 positive that intake Bromodeoxyuridine (Brdu). Conclusions: These results showed that the administration of SDF-1a increases the number of proliferating cells in the injured area in the spinal cord and improves functional recovery

Testicular seminoma – unusual histology and staging with sub epithelial spread of seminoma along the vas deferans

BACKGROUND: The route of local and metastatic spread of testicular seminoma is well recognised and accepted. The spread is via lymphatics to the paraaortic nodes. CASE PRESENTATION: We present a case report of testicular seminoma in a 56 year old man with previously unreported histological findings. In this case seminoma tumour cells did not appear to have spread by the expected lymphatic route. There was no involvement of retro-peritoneal para-aortic lymph nodes. The tumour appeared to have spread directly along the vas deferans in the sub epithelial plane to the mesenteric lymph nodes. CONCLUSION: This type of seminoma tumour spread has not previously been described and it is not a recognised route for metastasis by seminoma tumour. In this case the macroscopic clinical appearance was of a stage I tumour with normal tumour markers. However, the pathological stage of the tumour was surprisingly increased to stage III on the basis of histology and CT radiological findings. We present the unusual histological findings. In view of this unusual histological finding we reinforce the need for accurate staging and for resection of the spermatic cord close to the deep inguinal ring. Accurate staging is crucial in planning the treatment and follow up of seminoma and determines the prognosis

Field‐aligned currents during IMF ∼0

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95012/1/grl14623.pd

Reproducibility of optical coherence tomography airway imaging

Optical coherence tomography (OCT) is a promising imaging technique to evaluate small airway remodeling. However, the short-term insertion-reinsertion reproducibility of OCT for evaluating the same bronchial pathway has yet to be established. We evaluated 74 OCT data sets from 38 current or former smokers twice within a single imaging session. Although the overall insertion-reinsertion airway wall thickness (WT) measurement coefficient of variation (CV) was moderate at 12%, much of the variability between repeat imaging was attributed to the observer; CV for repeated measurements of the same airway (intra-observer CV) was 9%. Therefore, reproducibility may be improved by introduction of automated analysis approaches suggesting that OCT has potential to be an in-vivo method for evaluating airway remodeling in future longitudinal and intervention studies. (C) 2015 Optical Society of Americ