320 research outputs found
Multimodal Magnetic Resonance and Near-Infrared-Fluorescent Imaging of Intraperitoneal Ovarian Cancer Using a Dual-Mode-Dual-Gadolinium Liposomal Contrast Agent.
The degree of tumor removal at surgery is a major factor in predicting outcome for ovarian cancer. A single multimodality agent that can be used with magnetic resonance (MR) for staging and pre-surgical planning, and with optical imaging to aid surgical removal of tumors, would present a new paradigm for ovarian cancer. We assessed whether a dual-mode, dual-Gadolinium (DM-Dual-Gd-ICG) contrast agent can be used to visualize ovarian tumors in the peritoneal cavity by multimodal MR and near infra-red imaging (NIR). Intraperitoneal ovarian tumors (Hey-A8 or OVCAR3) in mice enhanced on MR two days after intravenous DM-Dual Gd-ICG injection compared to controls (SNR, CNR, p < 0.05, n = 6). As seen on open abdomen and excised tumors views and confirmed by optical radiant efficiency measurement, Hey-A8 or OVCAR3 tumors from animals injected with DM-Dual Gd-ICG had increased fluorescence (p < 0.05, n = 6). This suggests clinical potential to localize ovarian tumors by MR for staging and surgical planning, and, by NIR at surgery for resection
Cataclysmic Variables — X-rays and Optical Activity in V1223 Sgr and V709 Cas
Intermediate polars are a major fraction of all cataclysmic variables detected by INTEGRAL in hard X-ray. These objects have recently been proposed to be the dominant X-ray source population detected near the Galactic centre, and they also contribute significantly to X-ray diffuse Galactic ridge emission. Nevertheless, only 25% of all known intermediate polars have been detected in hard X-ray. This fact can be related to the activity state of these close interacting binaries.A multi-frequency (from optical to X-ray) investigation of intermediate polars is essential for understanding the physical mechanisms responsible for the observed activity of these objects
Developments in the production of soderberg paste for electrodes in ferro alloy furnaces
Using raw petroleum coke as raw-material, NML has devel-oped a dense carbon aggregate as a substitute for gas calcined anthracite. This dense carbon aggregate has been used for making soderberg paste, the properties of which have been studied and compared with a Norwegian and two indigenous pastes. The suitability of this material has been tested on a commercial scale in ferro alloy and pig iron furnaces.
Attempts also have been made to produce dense carbon aggregate by partial replacement of petroleum coke with low ash coal and the study of its properties have been described in this paper
Wind mass transfer in S-type symbiotic binaries III. Confirmation of a wind focusing in EG Andromedae from the nebular [OIII]\lambda 5007 line
Context. The structure of the wind from the cool giants in symbiotic binaries
carries important information for understanding the wind mass transfer to their
white dwarf companions and its fuelling. Aims. In this paper, we indicate a
non-spherical distribution of the neutral wind zone around the red giant (RG)
in the symbiotic binary star, EG And. Methods. We achieved this aim by
analysing the periodic orbital variations of fluxes and radial velocities of
individual components of the H and [OIII]5007 lines observed
on our high-cadence medium (R 11 000) and high-resolution (R 38
000) spectra. Results. The asymmetric shaping of the neutral wind zone at the
near-orbital-plane region is indicated by: (i) the asymmetric course of the
H core emission fluxes along the orbit; (ii) the presence of their
secondary maximum around the orbital phase , which is possibly
caused by the refraction effect; and (iii) the properties of the H
broad wing emission originating by Raman scattering on H atoms. The wind is
substantially compressed from polar directions to the orbital plane as
constrained by the location of the [OIII]5007 line emission zones in
the vicinity of the RG at/around its poles. The corresponding mass-loss rate
from the polar regions of Msun/yr is a factor of lower than the average rate of Msun/yr derived from
nebular emission of the ionised wind from the RG. Furthermore, it is two orders
of magnitude lower than that measured in the near-orbital-plane region from
Rayleigh scattering. Conclusions. The startling properties of the nebular
[OIII]5007 line in EG And provides an independent indication of the
wind focusing towards the orbital plane.Comment: 10 pages, 8 figure
Density asymmetry and wind velocities in the orbital plane of the symbiotic binary EG Andromedae
Context. Non-dusty late-type giants without a corona and large-scale
pulsations represent objects that do not fulfil the conditions under which
standard mass-loss mechanisms can be applied efficiently. The driving mechanism
of their winds is still unknown.
Aims. The main goal of this work is to match the radial velocities of
absorbing matter with a depth in the red giant (RG) atmosphere in the S-type
symbiotic star EG And.
Methods. We measured fluxes and radial velocities of ten FeI absorption lines
from spectroscopic observations with a resolution of ~30 000. At selected
orbital phases, we modelled their broadened profiles, including all significant
broadening mechanisms.
Results. The selected FeI absorption lines at 5151 - 6469A, originate at a
radial distance ~1.03 RG radii from its centre. The corresponding radial
velocity is typically ~1 km/s , which represents a few percent of the terminal
velocity of the RG wind. The high scatter of the radial velocities of several
km/s in the narrow layer of the stellar atmosphere points to the complex nature
of the near-surface wind mass flow. The average rotational velocity of 11 km/s
implies that the rotation of the donor star can contribute to observed focusing
the wind towards the orbital plane. The orbital variability of the absorbed
flux indicates the highest column densities of the wind in the area between the
binary components, even though the absorbing neutral material is geometrically
more extended from the opposite side of the giant. This wind density asymmetry
in the orbital plane region can be ascribed to gravitational focusing by the
white dwarf companion.
Conclusions. Our results suggest that both gravitational and rotational
focusing contribute to the observed enhancement of the RG wind towards the
orbital plane, which makes mass transfer by the stellar wind highly efficient.Comment: 12 pages, 10 figure
On the nature of the candidate T-Tauri star V501 Aurigae
We report new multi-colour photometry and high-resolution spectroscopic
observations of the long-period variable V501 Aur, previously considered to be
a weak-lined T-Tauri star belonging to the Taurus-Auriga star-forming region.
The spectroscopic observations reveal that V501 Aur is a single-lined
spectroscopic binary system with a 68.8-day orbital period, a slightly
eccentric orbit (e ~ 0.03), and a systemic velocity discrepant from the mean of
Taurus-Auriga. The photometry shows quasi-periodic variations on a different,
~55-day timescale that we attribute to rotational modulation by spots. No
eclipses are seen. The visible object is a rapidly rotating (vsini ~ 25 km/s)
early K star, which along with the rotation period implies it must be large (R
> 26.3 Rsun), as suggested also by spectroscopic estimates indicating a low
surface gravity. The parallax from the Gaia mission and other independent
estimates imply a distance much greater than the Taurus-Auriga region,
consistent with the giant interpretation. Taken together, this evidence
together with a re-evaluation of the LiI~6707 and H lines
shows that V501 Aur is not a T-Tauri star, but is instead a field binary with a
giant primary far behind the Taurus-Auriga star-forming region. The large mass
function from the spectroscopic orbit and a comparison with stellar evolution
models suggest the secondary may be an early-type main-sequence star.Comment: 13 pages, 7 figures. Accepted to MNRA
- …