77 research outputs found
Initial mass function variability from the integrated light of diverse stellar systems
Galaxie
An expression signature of the angiogenic response in gastrointestinal neuroendocrine tumours: correlation with tumour phenotype and survival outcomes.
BACKGROUND: Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are heterogeneous with respect to biological behaviour and prognosis. As angiogenesis is a renowned pathogenic hallmark as well as a therapeutic target, we aimed to investigate the prognostic and clinico-pathological role of tissue markers of hypoxia and angiogenesis in GEP-NETs. METHODS: Tissue microarray (TMA) blocks were constructed with 86 tumours diagnosed from 1988 to 2010. Tissue microarray sections were immunostained for hypoxia inducible factor 1α (Hif-1α), vascular endothelial growth factor-A (VEGF-A), carbonic anhydrase IX (Ca-IX) and somatostatin receptors (SSTR) 1â5, Ki-67 and CD31. Biomarker expression was correlated with clinico-pathological variables and tested for survival prediction using KaplanâMeier and Cox regression methods. RESULTS: Eighty-six consecutive cases were included: 51% male, median age 51 (range 16â82), 68% presenting with a pancreatic primary, 95% well differentiated, 51% metastatic. Higher grading (P=0.03), advanced stage (P<0.001), high Hif-1α and low SSTR-2 expression (P=0.03) predicted for shorter overall survival (OS) on univariate analyses. Stage, SSTR-2 and Hif-1α expression were confirmed as multivariate predictors of OS. Median OS for patients with SSTR-2+/Hif-1α-tumours was not reached after median follow up of 8.8 years, whereas SSTR-2-/Hif-1α+ GEP-NETs had a median survival of only 4.2 years (P=0.006). CONCLUSION: We have identified a coherent expression signature by immunohistochemistry that can be used for patient stratification and to optimise treatment decisions in GEP-NETs independently from stage and grading. Tumours with preserved SSTR-2 and low Hif-1α expression have an indolent phenotype and may be offered less aggressive management and less stringent follow up
High-Field Fermi Surface Properties in the Low Carrier Heavy Fermion Compound URu2Si2
We performed the Shubnikov-de Haas (SdH) experiments of the low carrier heavy
fermion compound URu2Si2 at high fields up to 34T and at low temperatures down
to 30mK. All main SdH branches named alpha, beta and gamma were observed for
all the measured field-directions (H // [001] -> [100], [100] -> [110] and
[001] -> [110]), indicating that these are attributed to the closed Fermi
surfaces with nearly spherical shapes. Anomalous split of branch alpha was
detected for the field along the basal plane, and the split immediately
disappears by tilting the field to [001] direction, implying a fingerprint of
the hidden order state. High field experiments reveal the complicated
field-dependence of the SdH frequencies and the cyclotron masses due to the
Zeeman spin-splitting associated with the Fermi surface reconstruction in the
hidden order state with small carrier numbers. A new SdH branch named omega
with large cyclotron mass of 25m0 was detected at high fields above 23T close
to the hidden order instabilities.Comment: 6 pages, 7 figures, accepted for publication in J. Phys. Soc. Jp
Pressure Collapse of the Magnetic Ordering in MnSi via Thermal Expansion
The itinerant quasi-ferromagnetic metal MnSi has been studied by detailed
thermal expansion measurements under pressures and magnetic fields. A sudden
decrease of the volume at the critical pressure Pc ~1.6 GPa has been observed
and is in good agreement with the pressure variation of the volume fraction of
the spiral magnetic ordering. This confirms that the magnetic order disappears
by a first order phase transition. The energy change estimated by the volume
discontinuity on crossing Pc is of similar order as the Zeeman energy of the
transition from the spiral ground state to a polarized paramagnetic one under
magnetic field. In contrast to the strong pressure dependence of the transition
temperature, the characteristic fields are weakly pressure dependent,
indicating that the strength of the ferromagnetic and the Dzyaloshinskii-Moriya
interactions do not change drastically around Pc. The evaluated results of the
thermal expansion coefficient and the magnetostriction are analyzed
thermodynamically. The Sommerfeld coefficient of the linear temperature term of
the specific heat is enhanced just below Pc. The magnetic field-temperature
phase diagrams in the ordered and paramagnetic phases are also compared.
Comparison is made with other heavy fermion compounds with first order phase
transition at 0 K.Comment: 9 pages, 13 figures, accepted to be published in JPS
A Study of Cosmic Ray Composition in the Knee Region using Multiple Muon Events in the Soudan 2 Detector
Deep underground muon events recorded by the Soudan 2 detector, located at a
depth of 2100 meters of water equivalent, have been used to infer the nuclear
composition of cosmic rays in the "knee" region of the cosmic ray energy
spectrum. The observed muon multiplicity distribution favors a composition
model with a substantial proton content in the energy region 800,000 -
13,000,000 GeV/nucleus.Comment: 38 pages including 11 figures, Latex, submitted to Physical Review
Superconductivity in Ce- and U-based "122" heavy-fermion compounds
This review discusses the heavy-fermion superconductivity in Ce- and U-based
compounds crystallizing in the body-centered tetragonal ThCr2Si2 structure.
Special attention will be paid to the theoretical background of these systems
which are located close to a magnetic instability.Comment: 12 pages, 9 figures. Invited topical review (special issue on "Recent
Developments in Superconductivity") Metadata and references update
Radial distribution of dust, stars, gas, and star-formation rate in DustPedia face-on galaxies
Aims. The purpose of this work is the characterization of the radial distribution of dust, stars, gas, and star-formation rate (SFR) in a sub-sample of 18 face-on spiral galaxies extracted from the DustPedia sample.
Methods. This study is performed by exploiting the multi-wavelength DustPedia database, from ultraviolet (UV) to sub-millimeter bands, in addition to molecular (12CO) and atomic (Hi) gas maps and metallicity abundance information available in the literature. We fitted the surface-brightness profiles of the tracers of dust and stars, the mass surface-density profiles of dust, stars, molecular gas, and total gas, and the SFR surface-density profiles with an exponential curve and derived their scale-lengths. We also developed a method to solve for the CO-to-H2 conversion factor (αCO) per galaxy by using dust- and gas-mass profiles.
Results. Although each galaxy has its own peculiar behavior, we identified a common trend of the exponential scale-lengths versus wavelength. On average, the scale-lengths normalized to the B-band 25 mag/arcsec2 radius decrease from UV to 70 ÎŒm, from 0.4 to 0.2, and then increase back up to ~0.3 at 500 microns. The main result is that, on average, the dust-mass surface-density scale-length is about 1.8 times the stellar one derived from IRAC data and the 3.6 ÎŒm surface brightness, and close to that in the UV. We found a mild dependence of the scale-lengths on the Hubble stage T: the scale-lengths of the Herschel bands and the 3.6 ÎŒm scale-length tend to increase from earlier to later types, the scale-length at 70 ÎŒm tends to be smaller than that at longer sub-mm wavelength with ratios between longer sub-mm wavelengths and 70 ÎŒm that decrease with increasing T. The scale-length ratio of SFR and stars shows a weak increasing trend towards later types. Our αCO determinations are in the range (0.3â9) Mâ pc-2 (K km s-1)-1, almost invariant by using a fixed dust-to-gas ratio mass (DGR) or a DGR depending on metallicity gradient
Sustainability in manufacturing processes: practices performed in metal forming, casting, heat treatment, welding and electrostatic painting
© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. This article aims to list the main sustainable practices developed in the processes of metal forming, casting, heat treatment, welding and electrostatic painting. When analysed the literature about sustainable manufacturing, a predominance of studies about machining is observed and the processes mentioned are few explored in academic studies. The research strategy used to reach the objective was systematic literature review, conducted for each process cited. Many sustainable practices were identified with prominence of better materials use and energy efficiency. The authors of this article believe that the information presented here can be useful for researches in their future studies and for industry professionals interested in improving manufacturing processes
Initial Mass Function Variability (or Not) among Low-velocity Dispersion, Compact Stellar Systems
Recommended from our members
Multiple Muon Events in Soudan 2
Abstract: This is a progress report on multiple muon events recorded by the Soudan 2 detector. 6 refs
- âŠ