1,559 research outputs found
Activation of phospholipase A2 by cannabinoids Lack of correlation with CNS effects
AbstractCannabinoids Δ1-tetrahydrocannabinol, cannabinol, cannabidiol and cannabigerol have been shown to affect directly the activity of phospholipase A2 in a cell-free assay. The compounds produced a biphasic activation of the enzyme, with EC50 values in the range 6.0–20.0 × 10−6 M and IC50 values in the range 50.0–150.0 × 10−6M. These results correlated well with the relative potencies reported for the stimulation of prostaglandin release from human synovial cells in vitro, confirming that activation of phospholipase A2 is the predominant action of cannabinoids on arachidonate metabolism in tissue culture. However, since Δ1-tetrahydrocannabinol is unique among these compounds in possessing cataleptic activity, it is unlikely that phospholipase A2 is the major receptor mediating the psychotropic effects of cannabis
TPA and resiniferatoxin-mediated activation of NADPH-oxidase A possible role for Rx-kinase augmentation of PKC
AbstractThe non-tumour promoting irritant, resiniferatoxin, was capable of activating the NADPH-oxidase respiratory burst of starch-elicited, but not resident mouse peritoneal macrophages in vitro. Unlike TPA, the response was synergised by incubation with zymosan. The Rx-stimulated NADPH-oxidase activity in a cell-free assay was selectively enhanced in the presence of exogenous Rx-kinase rather than PKC and in the absence of Ca2+. Since resiniferatoxin is a poor activator of PKC, it is probable that the Ca2+-independent Rx-kinase plays a role in activation of the macrophage respiratory burst following stimulation by zymosan
Winter Wheat In South Dakota
Winter wheat production in South Dakota has been constantly on the decline since 1916. In that year 2,775,000 bushels were produced. The crop reporter reports the 1920 production at a figure of 1,325,000 bushels less. At the same time the acreage decreased by 75,000 acres. Spring wheat also shows a steady decrease in production since 1918. The yield in 1916 was low. The decrease in spring wheat production based upon the highest year\u27s average is 63.2 per cent, while, basing our calculation upon the highest year\u27s production on winter wheat we have a decrease of only 47.7 percent. This in encouraging for the winter wheat growers of South Dakota when compared with that of spring wheat
Soybeans in South Dakota
The soybean is a summer annual legume, a native of eastern Asia. It has been grown in China and Japan for many hundreds of years, maiI1ly for human consumption. It was introduced into the United States early in the 19th century but did not become popular until a few decades ago. At that time importations were made into Kansas. Since that time its culture has rapidly spread over the United States. Its popularity is now generally recognized throughout the agricultural states. In localities where it has become increasingly difficult to secure stands of red clover the soybean is becoming more and more depended on for the restoration of nitrogen and as a source of green manure. The uses to which it is adapted are many. It is equally good for hogging-off, grain, soiling, silage, and is sometimes used as pasture and hay. Few other plants are so diversified in their usage. The ability of the plant to maintain itself and produce a crop during the hottest part of the summer is a point in its favor
Determining patterns in the composition of dissolved organic matter in fresh waters according to land use and management
In fresh waters, the origins of dissolved organic matter (DOM) have been found to exert a fundamental control on its reactivity, and ultimately, its ecosystem functional role. A detailed understanding of landscape scale factors that control the export of DOM to aquatic ecosystems is, therefore, pivotal if the effects of DOM flux to fresh waters are to be fully understood. In this study we present data from a national sampling campaign across the United Kingdom in which we explore the variability in DOM composition in three broad landscape types defined by similar precipitation, geology, land use and management, hydrology, and nutrient enrichment status. We characterised samples from fifty-one sites, grouping them into one of three major underlying classifications: circumneutral streams underlain by clay and mudstone (referred to as ‘clay’), alkaline streams underlain by Cretaceous Chalk or by Carboniferous or Jurassic Limestone (‘limestone’), and acidic streams in peatland catchments underlain by a range of low permeability lithologies (‘peat’). DOM composition was assessed through organic matter stoichiometry (organic carbon: organic nitrogen; organic carbon: organic phosphorus; C/N(P)DOM) and metrics derived from ultra-violet (UV)/visible spectroscopic analysis of DOM such as specific UV absorption (a254 nm; SUVA254). We found similar SUVA254, C/NDOM and DOM/a254 relationships within classifications, demonstrating that despite a large degree of heterogeneity within environments, catchments with shared environmental character and anthropogenic disturbance export DOM with a similar composition and character. Improving our understanding of DOM characterisation is important to help predict shifts in stream ecosystem function, and ecological responses to enrichment or mitigation efforts and how these may result in species composition shifts and biodiversity loss in freshwater ecosystems
Identificación del Ãndice de vulnerabilidad territorial a partir de modelos jerárquicos y heurÃsticos aplicando SOA
Auxiliar de InvestigaciónEn el proyecto se realiza el diseño y desarrollo de 4 servicios web implementando los modelos de toma de decisión (AHP, AHP FUZZY, ELECTRE y PROMETHEE), encargados de procesar datos obtenidos en campo en la primera fase del proyecto que se realizó a través de encuestas, formatos de entrevistas, talleres y metodologÃas de análisis. Los datos se procesaran de acuerdo al modelo de toma de decisión seleccionado, generando como resultado final un indicador de vulnerabilidad territorial.PregradoIngeniero de Sistema
Drag forces on inclusions in classical fields with dissipative dynamics
We study the drag force on uniformly moving inclusions which interact
linearly with dynamical free field theories commonly used to study soft
condensed matter systems. Drag forces are shown to be nonlinear functions of
the inclusion velocity and depend strongly on the field dynamics. The general
results obtained can be used to explain drag forces in Ising systems and also
predict the existence of drag forces on proteins in membranes due to couplings
to various physical parameters of the membrane such as composition, phase and
height fluctuations.Comment: 14 pages, 7 figure
Linking Backlund and Monodromy Charges for Strings on AdS_5 x S^5
We find an explicit relation between the two known ways of generating an
infinite set of local conserved charges for the string sigma model on AdS_5 x
S^5: the Backlund and monodromy approaches. We start by constructing the
two-parameter family of Backlund transformations for the string with an
arbitrary world-sheet metric. We then show that only for a special value of one
of the parameters the solutions generated by this transformation are compatible
with the Virasoro constraints. By solving the Backlund equations in a
non-perturbative fashion, we finally show that the generating functional of the
Backlund conservation laws is equal to a certain sum of the quasi-momenta. The
positions of the quasi-momenta in the complex spectral plane are uniquely
determined by the real parameter of the Backlund transform.Comment: 25 pages, 1 figur
Statistical distribution of quantum entanglement for a random bipartite state
We compute analytically the statistics of the Renyi and von Neumann entropies
(standard measures of entanglement), for a random pure state in a large
bipartite quantum system. The full probability distribution is computed by
first mapping the problem to a random matrix model and then using a Coulomb gas
method. We identify three different regimes in the entropy distribution, which
correspond to two phase transitions in the associated Coulomb gas. The two
critical points correspond to sudden changes in the shape of the Coulomb charge
density: the appearance of an integrable singularity at the origin for the
first critical point, and the detachement of the rightmost charge (largest
eigenvalue) from the sea of the other charges at the second critical point.
Analytical results are verified by Monte Carlo numerical simulations. A short
account of some of these results appeared recently in Phys. Rev. Lett. {\bf
104}, 110501 (2010).Comment: 7 figure
- …