1,413 research outputs found
Endoplasmic reticulum stress in malignancy.
The combination of relative nutrient deprivation and dysregulation of protein synthesis make malignant cells especially prone to protein misfolding. Endoplasmic reticulum stress, which results from protein misfolding within the secretory pathway, has a profound effect on cancer cell proliferation and survival. In this review, we examine the evidence implicating endoplasmic reticulum dysfunction in the pathology of cancer and discuss how recent findings may help to identify novel therapeutic targets
Chandra Observation of the Cluster Environment of a WAT Radio Source in Abell 1446
Wide-angle tail (WAT) radio sources are often found in the centers of galaxy
clusters where intracluster medium (ICM) ram pressure may bend the lobes into
their characteristic C-shape. We examine the low redshift (z=0.1035) cluster
Abell 1446, host to the WAT radio source 1159+583. The cluster exhibits
possible evidence for a small-scale cluster-subcluster merger as a cause of the
WAT radio source morphology. This evidence includes the presence of temperature
and pressure substructure along the line that bisects the WAT as well as a
possible wake of stripped interstellar material or a disrupted cool core to the
southeast of the host galaxy. A filament to the north may represent cool,
infalling gas that's contributing to the WAT bending while spectroscopically
determined redshifts of member galaxies may indicate some component of a merger
occurring along the line-of-sight. The WAT model of high flow velocity and low
lobe density is examined as another scenario for the bending of 1159+583. It
has been argued that such a model would allow the ram pressure due to the
galaxy's slow motion through the ICM to shape the WAT source. A temperature
profile shows that the cluster is isothermal (kT= 4.0 keV) in a series of
annuli reaching a radius of 400 kpc. There is no evidence of an ongoing cooling
flow. Temperature, abundance, pressure, density, and mass profiles, as well as
two-dimensional maps of temperature and pressure are presented.Comment: 40 AASTeX pages including 15 postscript figures; accepted for
publication in Ap
A Taxonomy of Extended Radio Sources in Clusters of Galaxies
At the request of the conference attendees, we have compiled a classification
of extended radio sources in clusters. These range from scales of tens of
parsecs to over a megaparsec in scale, and include both sources associated with
AGN and sources thought to derive from the electron population in the ionized
ICM. We pay special attention to distinguishing between the types of AGN in the
cores of cooling flow clusters and between the multiple classes of objects
referred to over the years as ``radio relics.'' We suggest new names based on
physical arguments for some of these classes of objects where their commonly
used names are inappropriate or confusing.Comment: 5 pages, to appear in "The Riddle of Cooling Flows in Galaxies and
Clusters of Galaxies," held in Charlottesvile, VA, May 31 - June 4, 2003, ed.
T. H. Reiprich, J. C. Kempner, and N. Soker,
http://www.astro.virginia.edu/coolflow
Hot Bubbles in Cooling Flow Clusters
As more cooling flow clusters of galaxies with central radio sources are
observed with the Chandra and XMM-Newton X-ray Observatories, more examples of
"bubbles" (low-emission regions in the X-ray coincident with radio emission)
are being found. These bubbles are surrounded by bright shells of X-ray
emission, and no evidence of current strong shocks has yet been found. Using an
analytic approach and some simplifying assumptions, we derive expressions
relating the size and location of a bubble, as well as the density contrast
between the bubble and the ambient medium, with the shock history of the
bubble. These can be applied straightforwardly to new observations. We find
that existing observations are consistent with a mild shock occurring in the
past, and with the bulk of the cool material in the X-ray shells being cooled
at the cluster center and then pushed outward by the radio source. Strong
shocks are ruled out unless they occurred more than 1 Gyr ago. We also discuss
Rayleigh-Taylor instabilities as well as the case of a bubble expanding into an
older bubble produced from a previous cycle of radio activity.Comment: 20 pages, Submitted to Ap
Characterization of electrospun nanocomposite scaffolds and biocompatibility with adipose-derived human mesenchymal stem cells
Electrospun nanocomposite scaffolds were fabricated by encapsulating multi-walled carbon nanotubes (MWNT) in poly (lactic acid) (PLA) nanofibers. Scanning electron microscopy (SEM) confirmed the fabrication of nanofibers, and transmission electron microscopy identified the alignment and dispersion of MWNT along the axis of the fibers. Tensile testing showed an increase in the tensile modulus for a MWNT loading of 0.25 wt% compared with electrospun nanofibrous mats without MWNT reinforcement. Conductivity measurements indicated that the confined geometry of the fibrous system requires only minute doping to obtain significant enhancements at 0.32 wt%. Adipose-derived human mesenchymal stem cells (hMSCs) were seeded on electrospun scaffolds containing 1 wt% MWNT and 0 wt% MWNT, to determine the efficacy of the scaffolds for cell growth, and the effect of MWNT on hMSC viability and proliferation over two weeks in culture. Staining for live and dead cells and DNA quantification indicated that the hMSCs were alive and proliferating through day 14. SEM images of hMSCs at 14 days showed morphological differences, with hMSCs on PLA well spread and hMSCs on PLA with 1% MWNT closely packed and longitudinally aligned
Chandra Observation of the Central Region of the Cooling Flow Cluster Abell 262: A Radio Source that is a Shadow of its Former Self?
We present a Chandra observation of the cooling flow cluster Abell 262.
Spectral fits show that the intracluster medium (ICM) in A262 cools by a factor
of three from 2.7 keV to 0.9 keV at the cluster center. A mass deposition rate
of Mdot = 19 +6/-5 Msun/yr is measured. Complex structure is found in the very
inner regions of the cluster, including knots of emission and a clear deficit
of emission to the east of the cluster center. The bright X-ray structures are
located in the same regions as optical line emission, indicating that cooling
to low temperatures has occurred in these regions. The X-ray deficit is
spatially coincident with the eastern radio lobe associated with the active
galactic nucleus hosted by the central cD galaxy. The region surrounding the
X-ray hole is cool, and shows no evidence that it has been strongly shocked.
This joins the ranks of other cooling flow clusters with Chandra-detected
bubbles blown by central radio sources. This source is different than the other
well-known cases, in that the radio source is orders of magnitude less luminous
and has produced a much smaller bubble. Comparing the energy output of the
radio source with the luminosity of the cooling gas shows that energy
transferred to the ICM from the radio source is insufficient to offset the
cooling flow unless the radio source is currently experiencing a less powerful
than average outburst, and was more powerful in the past.Comment: Astrophysical Journal, in press; 9 pages, 8 figure
Cost-Effectiveness of Laparoscopic Hysterectomy With Morcellation Compared With Abdominal Hysterectomy for Presumed Myomas
Hysterectomy for presumed leiomyomata is one of the most common surgical procedures performed in non-pregnant women in the United States. Laparoscopic hysterectomy (LH) with morcellation is an appealing alternative to abdominal hysterectomy (AH), but may result in dissemination of malignant cells and worse outcomes in the setting of an occult leiomyosarcoma. We sought to evaluate the cost-effectiveness of LH versus AH
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