432 research outputs found
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Competitive interactions between Douglas-fir or ponderosa pine and whiteleaf manzanita
Juvenile Douglas-fir, ponderosa pine, and whiteleaf manzanita
growth in southwest Oregon varied with density of co-developing
manzanita and presence of herbaceous cover. Plant xylem pressure
potential and stomatal conductance of each species was responsive
to competition-induced depletion of soil water. Rates varied among
species. The best correlations with growth usually accompanied a
two-year lag between stress and observed response. The densities
of manzanita observed ranged from 0 to 27000 seedlings per hectare.
Intra-specif Ic competition between individual manzanita
seedlings began at age three and became more accentuated, reducing
growth by age five. The competitive indices used were basal diameter,
canopy volume, above-ground biomass, and leaf area. Growth was always
least when herbaceous plants were present. Soil moisture depletion
was negatively correlated to amount of seedling growth. The community
parameters leaf area index, stand biomass, and stand basal area,
increased most rapidly at the highest densities, suggesting full site
occupancy did not occur by age five.
Six levels of manzanita density were provided by thinning and
planting to manipulate biomass, leaf area index, and canopy cover.
These parameters were used as inter-specific indices of competition
for Douglas-fir and ponderosa pine. Competitive influence of shrubs
on conifers was slight at age three, and increased progressively
through the fifth year. Stem volume in 1985 was most highly
correlated with manzanita canopy cover in 1983. Conifers grownnc
with both xaanzanita and herbaceous competition had the smallest stem
volumes, and those kept herb-free during the first and second years
of the study had smaller stem volumes than those that were herb-free
during the entire three years.
Species showed different strategies in water use. Manzanita
maintained high levels of xylem pressure potential with high levels
of stomatal conductance. Douglas-fir had intermediate level of
xylem pressure potential, and pine was lowest. Douglas-fir and pine
had similar stomatal conductance. This suggests the pine had access
to soil water that the Douglas-fir and manzanita could not exploit
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Glyphosate and hexazinone mixtures : effects on weeds and Douglas-fir transplants
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Bone Morphogenetic Proteinâ2 Decreases MicroRNAâ30b and MicroRNAâ30c to Promote Vascular Smooth Muscle Cell Calcification
Background: Vascular calcification resembles bone formation and involves vascular smooth muscle cell (SMC) transition to an osteoblastâlike phenotype to express Runx2, a master osteoblast transcription factor. One possible mechanism by which Runx2 protein expression is induced is downregulation of inhibitory microRNAs (miR). Methods and Results: Human coronary artery SMCs (CASMCs) treated with bone morphogenetic proteinâ2 (BMPâ2; 100 ng/mL) demonstrated a 1.7âfold (P<0.02) increase in Runx2 protein expression at 24 hours. A miR microarray and target prediction database analysis independently identified miRâ30b and miRâ30c (miRâ30bâc) as miRs that regulate Runx2 expression. Realâtimeâpolymerase chain reaction confirmed that BMPâ2 decreased miRâ30b and miRâ30c expression. A luciferase reporter assay verified that both miRâ30b and miRâ30c bind to the 3âČâuntranslated region of Runx2 mRNA to regulate its expression. CASMCs transfected with antagomirs to downregulate miRâ30bâc demonstrated significantly increased Runx2, intracellular calcium deposition, and mineralization. Conversely, forced expression of miRâ30bâc by transfection with preâmiRâ30bâc prevented the increase in Runx2 expression and mineralization of SMCs. Calcified human coronary arteries demonstrated higher levels of BMPâ2 and lower levels of miRâ30b than did noncalcified donor coronary arteries. Conclusions: BMPâ2 downregulates miRâ30b and miRâ30c to increase Runx2 expression in CASMCs and promote mineralization. Strategies that modulate expression of miRâ30b and miRâ30c may influence vascular calcification
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Natural and artificial regeneration of whiteleaf manzanita in competition studies
At three sites in southwest Oregon, uniform stands of whiteleaf manzanita were created for future studies on the effects of manzanita competition on Douglas-fir and ponderosa pine plantations. The sites were marked according to grids and nearby 2-year-old seedlings were lifted and transplanted to fill in gaps in the natural stands. Some plots were treated with a mixture of simazine, glyphosate, and 2,4-D to control weeds, and some were left untreated. After one year, survival of natural seedlings that were not transplanted was 98.0 and 95.3 percent on treated and untreated plots. Survival of transplanted seedlings was 66 and 92 percent on treated and untreated plots. Residual herbicides in the soil may have decreased the survival of transplanted seedlings. A uniform stocking of manzanita can be achieved by transplanting natural seedlings and controlling weeds with a minimum amount of herbicides
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Efficacy of imazapyr and metsulfuron methyl for site preparation and conifer release in the Oregon coast range
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Can we control brush by helicopter spraying before timber harvest?
Aerial application of fosamine ammonium or glyphosate at moderate rates was not adequate for controlling understory brush before final harvesting of mature Douglas-fir (Pseudotsuga menziesii) stands or for reducing vigor of post-harvest sprouting. Symptoms of herbicide injury were those associated with low application rates, suggesting that the canopy intercepted too much of the chemicals for adequate brush treatment. Site-preparation effects of logging were more pronounced than those of herbicide treatment in curbing future dominance by brush. Shrub species composition did not change as a result of spraying, logging, or both. Controlling understory brush with herbicides before harvest may require aerial application at higher rates or use of ground equipment where coniferous overstories are dense
TCR-engineered adoptive cell therapy effectively treats intracranial murine glioblastoma
BACKGROUND: Adoptive cellular therapies with chimeric antigen receptor T cells have revolutionized the treatment of some malignancies but have shown limited efficacy in solid tumors such as glioblastoma and face a scarcity of safe therapeutic targets. As an alternative, T cell receptor (TCR)-engineered cellular therapy against tumor-specific neoantigens has generated significant excitement, but there exist no preclinical systems to rigorously model this approach in glioblastoma.
METHODS: We employed single-cell PCR to isolate a TCR specific for the Imp3
RESULTS: We isolated and characterized the 3Ă1.1C TCR that displayed a high affinity for mImp3 but no wild-type cross-reactivity. To provide a source of mImp3-specific T cells, we generated the MISTIC mouse. In a model of adoptive cellular therapy, the infusion of activated MISTIC T cells resulted in rapid intratumoral infiltration and profound antitumor effects with long-term cures in a majority of GL261-bearing mice. The subset of mice that did not respond to the adoptive cell therapy showed evidence of retained neoantigen expression but intratumoral MISTIC T cell dysfunction. The efficacy of MISTIC T cell therapy was lost in mice bearing a tumor with heterogeneous mImp3 expression, showcasing the barriers to targeted therapy in polyclonal human tumors.
CONCLUSIONS: We generated and characterized the first TCR transgenic against an endogenous neoantigen within a preclinical glioma model and demonstrated the therapeutic potential of adoptively transferred neoantigen-specific T cells. The MISTIC mouse provides a powerful novel platform for basic and translational studies of antitumor T-cell responses in glioblastoma
Statistical Characterization of the Chandra Source Catalog
The first release of the Chandra Source Catalog (CSC) contains ~95,000 X-ray
sources in a total area of ~0.75% of the entire sky, using data from ~3,900
separate ACIS observations of a multitude of different types of X-ray sources.
In order to maximize the scientific benefit of such a large, heterogeneous
data-set, careful characterization of the statistical properties of the
catalog, i.e., completeness, sensitivity, false source rate, and accuracy of
source properties, is required. Characterization efforts of other, large
Chandra catalogs, such as the ChaMP Point Source Catalog (Kim et al. 2007) or
the 2 Mega-second Deep Field Surveys (Alexander et al. 2003), while
informative, cannot serve this purpose, since the CSC analysis procedures are
significantly different and the range of allowable data is much less
restrictive. We describe here the characterization process for the CSC. This
process includes both a comparison of real CSC results with those of other,
deeper Chandra catalogs of the same targets and extensive simulations of
blank-sky and point source populations.Comment: To be published in the Astrophysical Journal Supplement Series (Fig.
52 replaced with a version which astro-ph can convert to PDF without issues.
Hospital Preparedness and SARS
On May 23, 2003, Toronto experienced the second phase of a severe acute respiratory syndrome (SARS) outbreak. Ninety cases were confirmed, and >620 potential cases were managed. More than 9,000 persons had contact with confirmed or potential case-patients; many required quarantine. The main hospital involved during the second outbreak was North York General Hospital. We review this hospitalâs response to, and management of, this outbreak, including such factors as building preparation and engineering, personnel, departmental workload, policies and documentation, infection control, personal protective equipment, training and education, public health, management and administration, follow-up of SARS patients, and psychological and psychosocial management and research. We also make recommendations for other institutions to prepare for future outbreaks, regardless of their origin
Cu-II(atsm) Attenuates Neuroinflammation
Background: Neuroinflammation and biometal dyshomeostasis are key pathological features of several neurodegenerative diseases, including Alzheimer's disease (AD). Inflammation and biometals are linked at the molecular level through regulation of metal buffering proteins such as the metallothioneins. Even though the molecular connections between metals and inflammation have been demonstrated, little information exists on the effect of copper modulation on brain inflammation. Methods: We demonstrate the immunomodulatory potential of the copper bis(thiosemicarbazone) complex Cu-II(atsm) in an neuroinflammatory model in vivo and describe its anti-inflammatory effects on microglia and astrocytes in vitro. Results: By using a sophisticated in vivo magnetic resonance imaging (MRI) approach, we report the efficacy of Cu-II(atsm) in reducing acute cerebrovascular inflammation caused by peripheral administration of bacterial lipopolysaccharide (LPS). Cu-II(atsm) also induced anti-inflammatory outcomes in primary microglia [significant reductions in nitric oxide (NO), monocyte chemoattractant protein 1 (MCP-1), and tumor necrosis factor (TNF)] and astrocytes [significantly reduced NO, MCP-1, and interleukin 6 (IL-6)] in vitro. These anti-inflammatory actions were associated with increased cellular copper levels and increased the neuroprotective protein metallothionein-1 (MT1) in microglia and astrocytes. Conclusion: The beneficial effects of Cu-II(atsm) on the neuroimmune system suggest copper complexes are potential therapeutics for the treatment of neuroinflammatory conditions.Peer reviewe
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