397 research outputs found
The small-scale structure of the fluctuating passive scalar field in a turbulent boundary layer
Issued as final reportNational Science Foundatio
Acquisition of a research and teaching salt water flume at Priest Landing, GA.
Issued as final reportNational Science Foundation (U.S.
Personality Change as a Validation of the Bereiter Differential-Change Scales
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67011/2/10.1177_001316446802800112.pd
Globular Cluster Photometry with the Hubble Space Telescope VII. Color Gradients and Blue Stragglers in the Central Region of M30 (NGC 7099) from WFPC2 Observations
We present F555W (V), F439W (B), and F336W (U) photometry of 9507 stars in
the central 2' of the dense, post core collapse cluster M30 (NGC 7099) derived
from HST WFPC2 images. These data are used to study the mix of stellar
populations in the central region of the cluster. Forty eight blue straggler
stars are identified and are found to be strongly concentrated towards the
center. The specific frequency of blue stragglers, F_BSS\equiv
N(BSS)/N(V<V_HB+2), is 0.25\pm 0.05 in the inner region of M30 (r<20''),
significantly higher than the frequency found in other clusters. The shape of
M30's BSS luminosity function resembles the prediction of the collisional
formation model and is inconsistent with the binary merger model, of Bailyn and
Pinsonneault. An unusually blue star (B=18.6,B-V=-0.97), possibly a cataclysmic
variable based on its color, is found about 1.2'' from the center. Bright RG
stars appear to be depleted by a factor of 2--3 in the inner r<10'' relative to
fainter giants, subgiants, and MSTO stars (95% significance). We confirm that
there is a radial gradient in the color of the cluster light, going from
B-V=0.82 at r=1' to B-V=0.45 in the central 10''. The central depletion of the
bright RG is responsible for about half of the observed color gradient; the
rest of the gradient is caused by the relative underabundance of faint red MS
stars near the center (presumably a result of mass segregation). The luminosity
function of M30's evolved stars does not match the luminosity function shape
derived from standard stellar evolutionary models: the ratio of the number of
bright giants to the number of turnoff stars in the cluster is 30% higher than
predicted by the model (3.8\sigma effect), roughly independent of RG brightness
over the range M_V=-2 to +2. (abridged)Comment: To appear in the Astronomical Journal. 42 pages, 13 figures, 4
tables, full resolution figures and complete data tables available at
ftp://eku.sns.ias.edu/pub/GLOBULAR_CLUSTERS/m30-ppr7/ or
http://www.ucolick.org/~zodiac/m30
Optimal Elevation of β-Cell 11β-Hydroxysteroid Dehydrogenase Type 1 Is a Compensatory Mechanism That Prevents High-Fat Diet–Induced β-Cell Failure
Type 2 diabetes ultimately results from pancreatic β-cell failure. Abnormally elevated intracellular regeneration of glucocorticoids by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in fat or liver may underlie pathophysiological aspects of the metabolic syndrome. Elevated 11β-HSD1 is also found in pancreatic islets of obese/diabetic rodents and is hypothesized to suppress insulin secretion and promote diabetes. To define the direct impact of elevated pancreatic β-cell 11β-HSD1 on insulin secretion, we generated β-cell–specific, 11β-HSD1–overexpressing (MIP-HSD1) mice on a strain background prone to β-cell failure. Unexpectedly, MIP-HSD1(tg/+) mice exhibited a reversal of high fat–induced β-cell failure through augmentation of the number and intrinsic function of small islets in association with induction of heat shock, protein kinase A, and extracellular signal–related kinase and p21 signaling pathways. 11β-HSD1(−/−) mice showed mild β-cell impairment that was offset by improved glucose tolerance. The benefit of higher β-cell 11β-HSD1 exhibited a threshold because homozygous MIP-HSD1(tg/tg) mice and diabetic Lep(db/db) mice with markedly elevated β-cell 11β-HSD1 levels had impaired basal β-cell function. Optimal elevation of β-cell 11β-HSD1 represents a novel biological mechanism supporting compensatory insulin hypersecretion rather than exacerbating metabolic disease. These findings have immediate significance for current therapeutic strategies for type 2 diabetes
Analysis of in vitro secretion profiles from adipose-derived cell populations
BACKGROUND: Adipose tissue is an attractive source of cells for therapeutic purposes because of the ease of harvest and the high frequency of mesenchymal stem cells (MSCs). Whilst it is clear that MSCs have significant therapeutic potential via their ability to secrete immuno-modulatory and trophic cytokines, the therapeutic use of mixed cell populations from the adipose stromal vascular fraction (SVF) is becoming increasingly common. METHODS: In this study we have measured a panel of 27 cytokines and growth factors secreted by various combinations of human adipose-derived cell populations. These were 1. co-culture of freshly isolated SVF with adipocytes, 2. freshly isolated SVF cultured alone, 3. freshly isolated adipocytes alone and 4. adherent adipose-derived mesenchymal stem cells (ADSCs) at passage 2. In addition, we produced an ‘in silico’ dataset by combining the individual secretion profiles obtained from culturing the SVF with that of the adipocytes. This was compared to the secretion profile of co-cultured SVF and adipocytes. Two-tailed t-tests were performed on the secretion profiles obtained from the SVF, adipocytes, ADSCs and the ‘in silico’ dataset and compared to the secretion profiles obtained from the co-culture of the SVF with adipocytes. A p-value of < 0.05 was considered statistically different. To assess the overall changes that may occur as a result of co-culture we compared the proteomes of SVF and SVF co-cultured with adipocytes using iTRAQ quantitative mass spectrometry. RESULTS: A co-culture of SVF and adipocytes results in a distinct secretion profile when compared to all other adipose-derived cell populations studied. This illustrates that cellular crosstalk during co-culture of the SVF with adipocytes modulates the production of cytokines by one or more cell types. No biologically relevant differences were detected in the proteomes of SVF cultured alone or co-cultured with adipocytes. CONCLUSIONS: The use of mixed adipose cell populations does not appear to induce cellular stress and results in enhanced secretion profiles. Given the importance of secreted cytokines in cell therapy, the use of a mixed cell population such as the SVF with adipocytes may be considered as an alternative to MSCs or fresh SVF alone
The Metallicity-Luminosity Relation, Effective Yields, and Metal Loss in Spiral and Irregular Galaxies
I present results on the correlation between galaxy mass, luminosity, and
metallicity for a sample of spiral and irregular galaxies having well-measured
abundance profiles, distances, and rotation speeds. Additional data for low
surface brightness galaxies from the literature are also included for
comparison. These data are combined to study the metallicity-luminosity and
metallicity-rotation speed correlations for spiral and irregular galaxies. The
metallicity luminosity correlation shows its familiar form for these galaxies,
a roughly uniform change in the average present-day O/H abundance of about a
factor 100 over 11 magnitudes in B luminosity. However, the O/H - V(rot)
relation shows a change in slope at a rotation speed of about 125 km/sec. At
faster V(rot), there appears to be no relation between average metallicity and
rotation speed. At lower V(rot), the metallicity correlates with rotation
speed. This change in behavior could be the result of increasing loss of metals
from the smaller galaxies in supernova-driven winds. This idea is tested by
looking at the variation in effective yield, derived from observed abundances
and gas fractions assuming closed box chemical evolution. The effective yields
derived for spiral and irregular galaxies increase by a factor of 10-20 from
V(rot) approximately 5 km/sec to V(rot) approximately 300 km/sec, asympotically
increasing to approximately constant y(eff) for V(rot) > 150 km/sec. The trend
suggests that galaxies with V(rot) < 100-150 km/sec may lose a large fraction
of their SN ejecta, while galaxies above this value tend to retain metals.Comment: 40 pages total, including 7 encapsulated postscript figures. Accepted
for publication in 20 Dec 2002 Ap
Pain and analgesic use associated with skeletal-related events in patients with advanced cancer and bone metastases
PURPOSE: Bone metastases secondary to solid tumors increase the risk of skeletal-related events (SREs), including the occurrence of pathological fracture (PF), radiation to bone (RB), surgery to bone (SB), and spinal cord compression (SCC). The aim of this study was to evaluate the impact of SREs on patients' pain, analgesic use, and pain interference with daily functioning.
METHODS: Data were combined from patients with solid tumors and bone metastases who received denosumab or zoledronic acid across three identically designed phase 3 trials (N = 5543). Pain severity (worst pain) and pain interference were assessed using the Brief Pain Inventory at baseline and each monthly visit. Analgesic use was quantified using the Analgesic Quantification Algorithm.
RESULTS: The proportion of patients with moderate/severe pain and strong opioid use generally increased in the 6 months preceding an SRE and remained elevated, while they remained relatively consistent over time in patients without an SRE. Regression analysis indicated that all SRE types were significantly associated with an increased risk of progression to moderate/severe pain and strong opioid use. PF, RB, and SCC were associated with significantly greater risk of pain interference overall. Results were similar for pain interference with emotional well-being. All SRE types were associated with significantly greater risk of pain interference with physical function.
CONCLUSIONS: SREs are associated with increased pain and analgesic use in patients with bone metastases. Treatments that prevent SREs may decrease pain and the need for opioid analgesics and reduce the impact of pain on daily functioning
Pain and analgesic use associated with skeletal-related events in patients with advanced cancer and bone metastases
PURPOSE: Bone metastases secondary to solid tumors increase the risk of skeletal-related events (SREs), including the occurrence of pathological fracture (PF), radiation to bone (RB), surgery to bone (SB), and spinal cord compression (SCC). The aim of this study was to evaluate the impact of SREs on patients' pain, analgesic use, and pain interference with daily functioning.
METHODS: Data were combined from patients with solid tumors and bone metastases who received denosumab or zoledronic acid across three identically designed phase 3 trials (N = 5543). Pain severity (worst pain) and pain interference were assessed using the Brief Pain Inventory at baseline and each monthly visit. Analgesic use was quantified using the Analgesic Quantification Algorithm.
RESULTS: The proportion of patients with moderate/severe pain and strong opioid use generally increased in the 6 months preceding an SRE and remained elevated, while they remained relatively consistent over time in patients without an SRE. Regression analysis indicated that all SRE types were significantly associated with an increased risk of progression to moderate/severe pain and strong opioid use. PF, RB, and SCC were associated with significantly greater risk of pain interference overall. Results were similar for pain interference with emotional well-being. All SRE types were associated with significantly greater risk of pain interference with physical function.
CONCLUSIONS: SREs are associated with increased pain and analgesic use in patients with bone metastases. Treatments that prevent SREs may decrease pain and the need for opioid analgesics and reduce the impact of pain on daily functioning
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