704 research outputs found
The relationship between P2X4 and P2X7: a physiologically important interaction?
Purinergic signaling within the kidney is becoming an important focus in the study of renal health and disease. The effectors of ATP signaling, the P2Y and P2X receptors, are expressed to varying extents in and along the nephron. There are many studies demonstrating the importance of the P2Y2 receptor on kidney function, and other P2 receptors are now emerging as participants in renal regulation. The P2X4 receptor has been linked to epithelial sodium transport in the nephron and expression levels of the P2X7 receptor are up-regulated in certain pathophysiological states. P2X7 antagonism has been shown to ameliorate rodent models of DOCA salt-induced hypertension and P2X4 null mice are hypertensive. Interestingly, polymorphisms in the genetic loci of P2X4 and P2X7 have been linked to blood pressure variation in human studies. In addition to the increasing evidence linking these two P2X receptors to renal function and health, a number of studies link the two receptors in terms of physical associations between their subunits, demonstrated both in vitro and in vivo. This review will analyze the current literature regarding interactions between P2X4 and P2X7 and assess the potential impact of these with respect to renal function
Global biodiversity indicators reflect the modeled impacts of protected area policy change
Global biodiversity indicators can be used to measure the status and trends of biodiversity relating to Convention on Biological Diversity (CBD) targets. Whether such indicators can support decision makers by distinguishing among policy options remains poorly evaluated. We tested the ability of two CBD indicators, the Living Planet Index and the Red List Index, to reflect projected changes in mammalian populations in sub-Saharan Africa in response to potential policies related to CBD targets for protected areas (PAs). We compared policy scenarios to expand the PA network, improve management effectiveness of the existing network, and combinations of the two, against business as usual. Both indicators showed that more effective management would provide greater benefits to biodiversity than expanding PAs alone. The indicators were able to communicate outcomes of modeled scenarios in a simple quantitative manner, but behaved differently. This work highlights both the considerable potential of indicators in supporting decisions, and the need to understand how indicators will respond as biodiversity changes
Polarized deep inelastic scattering at high energies and parity violating structure functions
A comprehensive analysis of deep inelastic scattering of polarized charged
leptons on polarized nucleons is presented; weak interaction contributions,
both in neutral and charged current processes, are taken into account and the
parity violating polarized nucleon structure functions are studied. Possible
ways of their measurements and their interpretations in the parton model are
discussed.Comment: (slightly modified version, includes a few new references and
corrects few misprints for publication), 14 pages in TeX (needs harvmac) no
figure, DFTT 80/9
Gamma^*, Z^* production in polarised p-p scattering as a probe of the proton spin structure
We present the results of a detailed study of the large transverse momentum
Drell-Yan process, pp --> (Gamma^*, Z^*)X --> l^+l^- X at collider energies,
with either one or both protons polarised, allowing the study of single- and
double-spin asymmetries respectively. We show how these asymmetries obtained
from angular distributions of the leptons in the Gamma^* (or Z^*) rest-frame,
can be used to get information on the polarised parton distributions. Numerical
results for the asymmetries and the cross-sections are presented, and the
sensitivity of the asymmetries to the initial parton distributions indicates
that these can be used as effective probes of the spin structure of the proton.Comment: Latex, 9 pages, 4 figures available on request, CERN-TH.6997/9
Instanton Contribution to the Quark Form Factor
The nonperturbative effects in the quark form factor are considered in the
Wilson loop formalism. The properties of the Wilson loops with cusp
singularities are studied taking into account the perturbative and
nonperturbative contributions, where the latter are considered within the
framework of the instanton liquid model. For the integration path corresponding
to this form factor -- the angle with infinite sides -- the explicit expression
for the vacuum expectation value of the Wilson operator is found to leading
order. The calculations are performed in the weak-field limit for the instanton
vacuum contribution and compared with the one- and two-loop order results for
the perturbative part. It is shown that the instantons produce the powerlike
corrections to the perturbative result, which are comparable in magnitude with
the perturbative part at the scale of order of the inverse average instanton
size. It is demonstrated that the instanton contributions to the quark form
factor are exponentiated to high orders in the small instanton density
parameter.Comment: Version coincident with the journal publication. LaTeX, 15 pages, 1
figur
Formalism for dilepton production via virtual photon bremsstrahlung in hadronic reactions
We derive a set of new formulas for various distributions in dilepton
production via virtual photon bremsstrahlung from pseudoscalar mesons and
unpolarized spin-one-half fermions. These formulas correspond to the leading
and sub-leading terms in the Low-Burnett-Kroll expansion for real photon
bremsstrahlung. The relation of our leading-term formulas to previous works is
also shown. Existing formulas are examined in the light of Lorentz covariance
and gauge invariance. Numerical comparison is made in a simple example, where
an "exact" formula and real photon data exist. The results reveal large
discrepancies among different bremsstrahlung formulas. Of all the leading-term
bremsstrahlung formulas, the one derived in this work agrees best with the
exact formula. The issues of M_T-scaling and event generators are also
addressed.Comment: 37 pages, RevTeX, epsf.sty, 10 embedded figure
Optimisation of the ActWELL lifestyle intervention programme for women attending routine NHS breast screening clinics
Acknowledgements The authors would like to acknowledge the assistance of Amy Hickman, and Eluned Hughes from Breast Cancer Now, for guidance on practical intervention perspectives, and Jill Hampton in manuscript preparation. Thanks also to all the members of our public advisory group. The Health Services Research Unit, University of Aberdeen, receives core funding from Scottish Government Chief Scientist Office. Funding This work was supported by The Scottish Government, grant number BC/Screening/17/01. The funders provided independent referee reports, which guided some of the study parameters (as described in the text). The funders have read this manuscript. In-kind support was given by Breast Cancer Now for facilitating this study.Peer reviewedPublisher PD
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