36,835 research outputs found
Impaired decidual natural killer cell regulation of vascular remodelling in early human pregnancies with high uterine artery resistance
During human pregnancy, natural killer (NK) cells accumulate in the maternal decidua, but their specific roles remain to be determined. Decidual NK (dNK) cells are present during trophoblast invasion and uterine spiral artery remodelling. These events are crucial for successful placentation and the provision of an adequate blood supply to the developing fetus. Remodelling of spiral arteries is impaired in the dangerous pregnancy complication pre-eclampsia. We studied dNK cells isolated from pregnancies at 9-14 weeks' gestation, screened by uterine artery Doppler ultrasound to determine resistance indices which relate to the extent of spiral artery remodelling. dNK cells were able to promote the invasive behaviour of fetal trophoblast cells, partly through HGF. Cells isolated from pregnancies with higher resistance indices were less able to do this and secreted fewer pro-invasive factors. dNK cells from pregnancies with normal resistance indices could induce apoptotic changes in vascular smooth muscle and endothelial cells in vitro, events of importance in vessel remodelling, partly through Fas signalling. dNK cells isolated from high resistance index pregnancies failed to induce vascular apoptosis and secreted fewer pro-apoptotic factors. We have modelled the cellular interactions at the maternal-fetal interface and provide the first demonstration of a functional role for dNK cells in influencing vascular cells. A potential mechanism contributing to impaired vessel remodelling in pregnancies with a higher uterine artery resistance is presented. These findings may be informative in determining the cellular interactions contributing to the pathology of pregnancy disorders where remodelling is impaired, such as pre-eclampsia. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd
Outdoor Recreation Valuation (ORVal) User Guide: Version 2.0
The ORVal Tool is web application developed by the Land, Environment, Economics and Policy
(LEEP) Institute at the University of Exeter with support from DEFRA. It can be accessed at:
http://leep.exeter.ac.uk/orval.Department for Environment, Food and Rural Affairs (Defra
Outdoor Recreation Valuation (ORVal) User Guide: Version 1.0
The ORVal Tool is web application developed by the Land, Environment, Economics and Policy
(LEEP) Institute at the University of Exeter with support from DEFRA. It can be accessed at:
http://leep.exeter.ac.uk/orval.Department for Environment, Food and Rural Affairs (Defra
Specifying ODP computational objects in Z
The computational viewpoint contained within the Reference Model of Open Distributed Processing (RM-ODP) shows how collections of objects can be configured within a distributed system to enable interworking. It prescribes certain capabilities that such objects are expected to possess and structuring rules that apply to how these objects can be configured with one another. This paper highlights how the specification language Z can be used to formalise these capabilities and the associated structuring rules, thereby enabling specifications of ODP systems from the computational viewpoint to be achieved
Accretion Disc Theory: From the Standard Model Until Advection
Accretion disc theory was first developed as a theory with the local heat
balance, where the whole energy produced by a viscous heating was emitted to
the sides of the disc. One of the most important new invention of this theory
was a phenomenological treatment of the turbulent viscosity, known as ''alpha''
prescription, when the (r) component of the stress tensor was
approximated by ( P) with a unknown constant . This
prescription played the role in the accretion disc theory as well important as
the mixing-length theory of convection for stellar evolution. Sources of
turbulence in the accretion disc are discussed, including nonlinear
hydrodynamical turbulence, convection and magnetic field role. In parallel to
the optically thick geometrically thin accretion disc models, a new branch of
the optically thin accretion disc models was discovered, with a larger
thickness for the same total luminosity. The choice between these solutions
should be done of the base of a stability analysis. The ideas underlying the
necessity to include advection into the accretion disc theory are presented and
first models with advection are reviewed. The present status of the solution
for a low-luminous optically thin accretion disc model with advection is
discussed and the limits for an advection dominated accretion flows (ADAF)
imposed by the presence of magnetic field are analysed.Comment: Roceeding of the Int. Workshop "Observational Evidence for Black
Holes in the Universe". Calcutta, 11-17 January 1998. Kluwer Acad. Pu
The ORVal Recreation Demand Model
Department for Environment, Food and Rural Affairs (Defra
Addressing the Collective Action Problem in Multiple-purchaser PES: An Experimental Investigation of Negotiated Payment Contributions
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Involving multiple-purchasers in a PES scheme has the potential to deliver numerous benefits including cost-sharing, expanded financing and broadened scope. That few such schemes exist is evidence of a classic market failure resulting from incentives to free-ride on the payments of other purchasers. In the context of an experimental investigation, this paper
explores the role of negotiation and binding pre-commitments to payments in solving that collective action problem. Our novel experimental setup involves two purchasers seeking a level of payment acceptable to a single provider while also agreeing their own individual contributions to that payment. Contrasting treatments are used to explore complexities of the
conditions under which negotiations might take place including asymmetries between the purchasers, treatments with incomplete information and treatments with uncertainty over the levels of benefit. We find that those complexities change the ease with which a negotiated agreement is achieved as well as the relative size of the payoffs enjoyed by the different
parties to the negotiations Our findings are generally positive, showing that under many circumstances parties to a multiple-purchaser PES can successfully negotiate a mutually agreeable schedule of payments and contributions.This project was carried out as part of the Defra Payments for Ecosystem Services (PES) Pilot Research Projects: River Fowey Improvement Scheme [NE0131]. It was also supported by a University of East Anglia studentship. Funding support is gratefully acknowledged
ïżŒMinimum target prices for production of direct acting antivirals and associated diagnostics to combat Hepatitis C Virus
Combinations of direct-acting antivirals (DAAs) can cure hepatitis C virus (HCV) in the majority of treatment-naĂŻve patients. Mass treatment programs to cure HCV in developing countries are only feasible if the costs of treatment and laboratory diagnostics are very low. This analysis aimed to estimate minimum costs of DAA treatment and associated diagnostic monitoring. Clinical trials of HCV DAAs were reviewed to identify combinations with consistently high rates of sustained virological response across hepatitis C genotypes. For each DAA, molecular structures, doses, treatment duration, and components of retrosynthesis were used to estimate costs of large-scale, generic production. Manufacturing costs per gram of DAA were based upon treating at least 5 million patients per year and a 40% margin for formulation. Costs of diagnostic support were estimated based on published minimum prices of genotyping, HCV antigen tests plus full blood count/clinical chemistry tests. Predicted minimum costs for 12-week courses of combination DAAs with the most consistent efficacy results were: US152 for sofosbuvir+ribavirin; US115 for MK-8742+MK-5172. Diagnostic testing costs were estimated at US34 for two HCV antigen tests and US171-360 per person without genotyping or US$261-450 per person with genotyping. These cost estimates assume that existing large-scale treatment programs can be established. (Hepatology 2015;61:1174â1182
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