887 research outputs found
Sliding tethered ligands add topological interactions to the toolbox of ligand-receptor design
International audienceAdhesion in the biological realm is mediated by specific lock-and-key interactions between ligand-receptor pairs. These complementary moieties are ubiquitously anchored to substrates by tethers that control the interaction range and the mobility of the ligands and receptors, thus tuning the kinetics and strength of the binding events. Here we add sliding anchoring to the toolbox of ligand-receptor design by developing a family of tethered ligands for which the spacer can slide at the anchoring point. Our results show that this additional sliding degree of freedom changes the nature of the adhesive contact by extending the spatial range over which binding may sustain a significant force. By introducing sliding tethered ligands with self-regulating length, this work paves the way for the development of versatile and reusable bio-adhesive substrates with potential applications for drug delivery and tissue engineering
Complementary currencies for sustainable development in Kenya: the case of the Bangla-Pesa
This paper is a report on the development of a complementary currency system that allows Kenyans in informal settlements to trade goods and services and meets sustainable development objectives. The system in this report, Bangla-Pesa, uses a mutual-credit model through a network of local business, including many whose owners fall under the extreme poverty line. The paper documents the reasons for its creation, how it was launched, the immediate positive benefits upon launch, and some of the difficulties faced. Bangla-Pesa is shown to facilitate exchanges of roughly 50 Euros in value per day among 109 businesses, which should raise living standards in the community primarily through the utilization of excess business capacity. After only a week of circulation – Bangla-Pesa helped community members increase sales an estimated 22% through capacity trading. This system’s implementation and governance model are detailed with the aim of improving upon and replicating the model for future sustainable development programs
General bounds on non-standard neutrino interactions
We derive model-independent bounds on production and detection non-standard
neutrino interactions (NSI). We find that the constraints for NSI parameters
are around O(10^{-2}) to O(10^{-1}). Furthermore, we review and update the
constraints on matter NSI. We conclude that the bounds on production and
detection NSI are generally one order of magnitude stronger than their matter
counterparts.Comment: 18 pages, revtex4, 1 axodraw figure. Minor changes, matches published
versio
Loop bounds on non-standard neutrino interactions
We reconsider the bounds on non-standard neutrino interactions with matter
which can be derived by constraining the four-charged-lepton operators induced
at the loop level. We find that these bounds are model dependent. Naturalness
arguments can lead to much stronger constraints than those presented in
previous studies, while no completely model-independent bounds can be derived.
We will illustrate how large loop-contributions to four-charged-lepton
operators are induced within a particular model that realizes gauge invariant
non-standard interactions and discuss conditions to avoid these bounds. These
considerations mainly affect the constraint on the
non-standard coupling strength \eps_{e\mu}, which is lost. The only
model-independent constraints that can be derived are .
However, significant cancellations are required in order to saturate this
bound.Comment: Minor changes, version to be published in JHEP. 17 pages, 3 Axodraw
figures, REVTeX
Optimized Two-Baseline Beta-Beam Experiment
We propose a realistic Beta-Beam experiment with four source ions and two
baselines for the best possible sensitivity to theta_{13}, CP violation and
mass hierarchy. Neutrinos from 18Ne and 6He with Lorentz boost gamma=350 are
detected in a 500 kton water Cerenkov detector at a distance L=650 km (first
oscillation peak) from the source. Neutrinos from 8B and 8Li are detected in a
50 kton magnetized iron detector at a distance L=7000 km (magic baseline) from
the source. Since the decay ring requires a tilt angle of 34.5 degrees to send
the beam to the magic baseline, the far end of the ring has a maximum depth of
d=2132 m for magnetic field strength of 8.3 T, if one demands that the fraction
of ions that decay along the straight sections of the racetrack geometry decay
ring (called livetime) is 0.3. We alleviate this problem by proposing to trade
reduction of the livetime of the decay ring with the increase in the boost
factor of the ions, such that the number of events at the detector remains
almost the same. This allows to substantially reduce the maximum depth of the
decay ring at the far end, without significantly compromising the sensitivity
of the experiment to the oscillation parameters. We take 8B and 8Li with
gamma=390 and 656 respectively, as these are the largest possible boost factors
possible with the envisaged upgrades of the SPS at CERN. This allows us to
reduce d of the decay ring by a factor of 1.7 for 8.3 T magnetic field.
Increase of magnetic field to 15 T would further reduce d to 738 m only. We
study the sensitivity reach of this two baseline two storage ring Beta-Beam
experiment, and compare it with the corresponding reach of the other proposed
facilities.Comment: 17 pages, 3 eps figures. Minor changes, matches version accepted in
JHE
Perturbation Theory of Neutrino Oscillation with Nonstandard Neutrino Interactions
We discuss various physics aspects of neutrino oscillation with non-standard
interactions (NSI). We formulate a perturbative framework by taking \Delta
m^2_{21} / \Delta m^2_{31}, s_{13}, and the NSI elements \epsilon_{\alpha
\beta} (\alpha, \beta = e, \mu, \tau) as small expansion parameters of the same
order \epsilon. Within the \epsilon perturbation theory we obtain the S matrix
elements and the neutrino oscillation probability formula to second order
(third order in \nu_e related channels) in \epsilon. The formula allows us to
estimate size of the contribution of any particular NSI element
\epsilon_{\alpha beta} to the oscillation probability in arbitrary channels,
and gives a global bird-eye view of the neutrino oscillation phenomena with
NSI. Based on the second-order formula we discuss how all the conventional
lepton mixing as well as NSI parameters can be determined. Our results shows
that while \theta_{13}, \delta, and the NSI elements in \nu_e sector can in
principle be determined, complete measurement of the NSI parameters in the
\nu_\mu - \nu_\tau sector is not possible by the rate only analysis. The
discussion for parameter determination and the analysis based on the matter
perturbation theory indicate that the parameter degeneracy prevails with the
NSI parameters. In addition, a new solar-atmospheric variable exchange
degeneracy is found. Some general properties of neutrino oscillation with and
without NSI are also illuminated.Comment: manuscript restructured, discussion of new type of parameter
degeneracy added. 47 page
, and the neutrino mass hierarchy at a double baseline Li/B -Beam
We consider a -Beam facility where Li and B ions are
accelerated at , accumulated in a 10 Km storage ring and let
decay, so as to produce intense and beams. These beams
illuminate two iron detectors located at Km and
Km, respectively. The physics potential of this setup is analysed in full
detail as a function of the flux. We find that, for the highest flux ( ion decays per year per baseline), the sensitivity to
reaches ; the sign of
the atmospheric mass difference can be identified, regardless of the true
hierarchy, for ; and, CP-violation
can be discovered in 70% of the -parameter space for , having some sensitivity to CP-violation down to
for .Comment: 35 pages, 20 figures. Minor changes, matches the published versio
Calcineurin inhibitors cyclosporine A and tacrolimus induce vascular inflammation and endothelial activation through TLR4 signaling
The introduction of the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus greatly reduced the
rate of allograft rejection, although their chronic use is marred by a range of side effects, among them
vascular toxicity. In transplant patients, it is proved that innate immunity promotes vascular injury
triggered by ischemia-reperfusion damage, atherosclerosis and hypertension. We hypothesized that
activation of the innate immunity and inflammation may contribute to CNI toxicity, therefore we
investigated whether TLR4 mediates toxic responses of CNIs in the vasculature. Cyclosporine and
tacrolimus increased the production of proinflammatory cytokines and endothelial activation markers
in cultured murine endothelial and vascular smooth muscle cells as well as in ex vivo cultures of murine
aortas. CNI-induced proinflammatory events were prevented by pharmacological inhibition of TLR4.
Moreover, CNIs were unable to induce inflammation and endothelial activation in aortas from TLR4−/−
mice. CNI-induced cytokine and adhesion molecules synthesis in endothelial cells occurred even in the
absence of calcineurin, although its expression was required for maximal effect through upregulation
of TLR4 signaling. CNI-induced TLR4 activity increased O2
−/ROS production and NF-κB-regulated
synthesis of proinflammatory factors in cultured as well as aortic endothelial and VSMCs. These data
provide new insight into the mechanisms associated with CNI vascular inflammationThis work was supported by grants from the Instituto de Salud Carlos III (Ministerio de Economía Competitividad, Gobierno de España): FEDER funds ISCIII RETIC REDINREN RD12/0021, PI11/02242, PI13/00047, PI14/0041, PI14/00386, PI15/01460; Comunidad de Madrid (CIFRA S2010/BMD-2378); Sociedad Española de Nefrología. Salary support: RR-D:
CIFRA; CO-S: Fundación Conchita Rábago de Jiménez Díaz; CG-G and RRR-D: REDINREN; AO: Programa Intensificación Actividad Investigadora (ISCIII/Agencia Laín-Entralgo/CM); JE and MRO: Universidad Autónoma de Madrid; AMR: Contrato Miguel Serve (ISCIII
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