Abstract
We present ALMA Cycle 4 observations of CO(1-0), CO(3-2), and
13
CO(3-2) line emission in the brightest cluster galaxy (BCG) of RXJ0821+0752. This is one of the first detections of
13
CO ...line emission in a galaxy cluster. Half of the CO(3-2) line emission originates from two clumps of molecular gas that are spatially offset from the galactic center. These clumps are surrounded by diffuse emission that extends 8 kpc in length. The detected
13
CO emission is confined entirely to the two bright clumps, with any emission outside of this region lying below our detection threshold. Two distinct velocity components with similar integrated fluxes are detected in the
12
CO spectra. The narrower component (60 km s
−1
FWHM) is consistent in both velocity centroid and linewidth with
13
CO(3-2) emission, while the broader (130–160 km s
−1
), slightly blueshifted wing has no associated
13
CO(3-2) emission. A simple local thermodynamic model indicates that the
13
CO emission traces 2.1 × 10
9
M
⊙
of molecular gas. Isolating the
12
CO velocity component that accompanies the
13
CO emission yields a CO-to-H
2
conversion factor of
α
CO
= 2.3
M
⊙
(K km s
−1
)
−1
, which is a factor of two lower than the Galactic value. Adopting the Galactic CO-to-H
2
conversion factor in BCGs may therefore overestimate their molecular gas masses by a factor of two. This is within the object-to-object scatter from extragalactic sources, so calibrations in a larger sample of clusters are necessary in order to confirm a sub-Galactic conversion factor.
Metastatic spread, not primary tumor burden, is the leading cause of breast cancer deaths. For patient prognosis to improve, new systemic adjuvant therapies that are capable of effectively inhibiting ...the outgrowth of seeded tumor cells after surgical treatment of the primary breast tumor are needed. To facilitate the preclinical development of such therapies, relevant animal models of breast cancer metastasis that can mimic the postsurgical adjuvant setting are required. Here we developed a preclinical xenograft model of breast cancer metastasis where the primary tumor was removed by surgical resection before systemic adjuvant treatment. We used this model to assess the antimetastatic effect of postsurgical dietary intervention with the soy isoflavone genistein. The anticancer activity of genistein has been established in vitro and in vivo, however, few studies have tested the potential of genistein as an antimetastatic therapy. Using our model, we tested the efficacy of adjuvant treatment with genistein to inhibit the outgrowth of metastases postsurgery. To establish primary tumors, human breast carcinoma cells, MDA-MB-435/HAL, were implanted into the mammary fat pad of female nude mice. Primary tumors were left to grow for 5 weeks before being surgically removed. Mice were then randomized into two diet groups: control soy-free diet versus genistein-supplemented diet. Five weeks later, metastatic burden was assessed. Genistein reduced the percent metastatic burden in the lungs by 10-fold. These results indicate that dietary intervention following cancer surgery can affect the outgrowth of seeded tumor cells. The availability of well-characterized, clinically relevant animal models for studying factors that regulate metastatic outgrowth postsurgery will provide an important tool for developing new systemic adjuvant therapies.
Breast cancer remains a leading cause of morbidity and mortality in women, mainly due to the propensity of primary breast tumors to metastasize to regional and distant sites. Metastatic spread after ...the removal of a primary tumor can be difficult to identify, creating uncertainty in patients with regards to possible cancer recurrence. This is a particular problem in breast cancer, exemplified by the fact that recurrence can take place after decades of apparent disease-free survival. The mechanisms underlying tumor dormancy in breast cancer remain poorly understood, and this presents significant challenges to both experimental investigation and clinical management of breast cancer. This review will discuss what is currently known about the metastatic process and tumor dormancy, consider the growing evidence that cancer stem cells may contribute to tumor progression and dormancy, and speculate about the clinical importance and implications of this research.
We report a measurement of the nuclear polarization of laser-cooled, optically pumped 37K atoms which will allow us to precisely measure angular correlation parameters in the ${\beta }^{+}$-decay of ...the same atoms. These results will be used to test the V ₋ A framework of the weak interaction at high precision. At the Triumf neutral atom trap (Trinat), a magneto-optical trap confines and cools neutral 37K atoms and optical pumping spin-polarizes them. We monitor the nuclear polarization of the same atoms that are decaying in situ by photoionizing a small fraction of the partially polarized atoms and then use the standard optical Bloch equations to model their population distribution. We obtain an average nuclear polarization of $\bar{P}=0.9913\pm 0.0009$, which is significantly more precise than previous measurements with this technique. Since our current measurement of the β-asymmetry has $0.2 \% $ statistical uncertainty, the polarization measurement reported here will not limit its overall uncertainty. This result also demonstrates the capability to measure the polarization to $\lt 0.1 \% $, allowing for a measurement of angular correlation parameters to this level of precision, which would be competitive in searches for new physics.
Recent technological advances have led to an increasing ability to detect isolated tumour cells and groups of tumour cells in patients' blood, lymph nodes or bone marrow. However, the clinical ...significance of these cells is unclear. Should they be considered as evidence of metastasis, necessitating aggressive treatment, or are they in some cases unrelated to clinical outcome? Quantitative experimental studies on the basic biology of metastatic inefficiency are providing clues that may help in understanding the significance of these cells. This understanding will be of use in guiding clinical studies to assess the significance of isolated tumour cells and micrometastases in cancer patients.
Although lymphatic dissemination is a major route for breast cancer metastasis, there has been little work to determine what factors control the ability of tumor cells to survive, establish and show ...progressive growth in a lymph node environment. This information is of particular relevance now, in the era of sentinel lymph node biopsy, where smaller intranodal tumor deposits are being detected earlier in the course of disease, the clinical relevance of which is uncertain. In this study, we compared differentially expressed genes in cell lines of high (468LN) vs. low (468GFP) lymphatic metastatic ability, and related these to clinical literature on genes associated with lymphatic metastatic ability and prognosis, to identify genes of potential clinical relevance. This approach revealed differential expression of a set of genes associated with 'cancer stem cell-like' properties, as well as networks of genes potentially associated with survival and autonomous growth. We explored these differences functionally and found that 468LN cells have a higher proportion of cells with a cancer stem cell-like (CD44+/CD24-) phenotype, have a higher clonogenic potential and a greater ability to survive, establish and grow in a foreign (lymph node and 3D Matrigel) microenvironment, relative to 468GFP cells. Differentially expressed genes which reflect these functions provide candidates for investigation as potential targets for therapy directed against early lymphatic metastasis.
Abstract
We present atmospheric gas entropy profiles for 40 early-type galaxies and 110 clusters spanning several decades of halo mass, atmospheric gas mass, radio jet power, and galaxy type. We show ...that within ∼0.1
R
2500
the entropy profiles of low-mass systems, including ellipticals, brightest cluster galaxies, and spiral galaxies, scale approximately as
K
∝
R
2/3
. Beyond ∼0.1
R
2500
entropy profiles are slightly shallower than the
K
∝
R
1.1
profile expected from gravitational collapse alone, indicating that heating by active galactic nuclei (AGN) feedback extends well beyond the central galaxy. We show that the
K
∝
R
2/3
entropy profile shape indicates that thermally unstable cooling is balanced by heating where the inner cooling and free-fall timescales approach a constant ratio. Hot atmospheres of elliptical galaxies have a higher rate of heating per gas particle compared to those of central cluster galaxies. This excess heating may explain why some central cluster galaxies are forming stars while most early-type galaxies have experienced no significant star formation for billions of years. We show that the entropy profiles of six lenticular and spiral galaxies follow the
R
2/3
form. The continuity between central galaxies in clusters, giant ellipticals, and spirals suggests perhaps that processes heating the atmospheres of elliptical and brightest cluster galaxies are also active in spiral galaxies.
We report ALMA Early Science observations of the A1835 brightest cluster galaxy (BCG) in the CO (3-2) and CO (1-0) emission lines. We detect 5 × 10{sup 10} M {sub ☉} of molecular gas within 10 kpc of ...the BCG. Its ensemble velocity profile width of ∼130 km s{sup –1} FWHM is too narrow for the molecular clouds to be supported in the galaxy by dynamic pressure. The gas may instead be supported in a rotating, turbulent disk oriented nearly face-on. Roughly 10{sup 10} M {sub ☉} of molecular gas is projected 3-10 kpc to the northwest and to the east of the nucleus with line-of-sight velocities lying between –250 km s{sup –1} and +480 km s{sup –1} with respect to the systemic velocity. The high-velocity gas may be either inflowing or outflowing. However, the absence of high-velocity gas toward the nucleus that would be expected in a steady inflow, and its bipolar distribution on either side of the nucleus, are more naturally explained as outflow. Star formation and radiation from the active galactic nucleus (AGN) are both incapable of driving an outflow of this magnitude. The location of the high-velocity gas projected behind buoyantly rising X-ray cavities and favorable energetics suggest an outflow driven by the radio AGN. If so, the molecular outflow may be associated with a hot outflow on larger scales reported by Kirkpatrick and colleagues. The molecular gas flow rate of approximately 200 M {sub ☉} yr{sup –1} is comparable to the star formation rate of 100-180 M {sub ☉} yr{sup –1} in the central disk. How radio bubbles would lift dense molecular gas in their updrafts, how much gas will be lost to the BCG, and how much will return to fuel future star formation and AGN activity are poorly understood. Our results imply that radio-mechanical (radio-mode) feedback not only heats hot atmospheres surrounding elliptical galaxies and BCGs, but it is able to sweep higher density molecular gas away from their centers.
We present Atacama Large Millimeter/submillimeter Array and Multi-Unit Spectroscopic Explorer observations of the brightest cluster galaxy in Abell 2597, a nearby (z = 0.0821) cool core cluster of ...galaxies. The data map the kinematics of a three billion solar mass filamentary nebula that spans the innermost 30 kpc of the galaxy's core. Its warm ionized and cold molecular components are both cospatial and comoving, consistent with the hypothesis that the optical nebula traces the warm envelopes of many cold molecular clouds that drift in the velocity field of the hot X-ray atmosphere. The clouds are not in dynamical equilibrium, and instead show evidence for inflow toward the central supermassive black hole, outflow along the jets it launches, and uplift by the buoyant hot bubbles those jets inflate. The entire scenario is therefore consistent with a galaxy-spanning "fountain," wherein cold gas clouds drain into the black hole accretion reservoir, powering jets and bubbles that uplift a cooling plume of low-entropy multiphase gas, which may stimulate additional cooling and accretion as part of a self-regulating feedback loop. All velocities are below the escape speed from the galaxy, and so these clouds should rain back toward the galaxy center from which they came, keeping the fountain long lived. The data are consistent with major predictions of chaotic cold accretion, precipitation, and stimulated feedback models, and may trace processes fundamental to galaxy evolution at effectively all mass scales.
PDF
