90 research outputs found
Gamma oscillatory activity in vitro: a model system to assess pathophysiological mechanisms of comorbidity between autism and epilepsy.
Autism spectrum disorder (ASD) and temporal lobe epilepsy exhibit remarkable comorbidity, but for reasons not clearly understood. To reveal a common pathophysiological mechanism, we here describe and characterize an in vitro epileptiform activity in the rat hippocampus that exhibits common features with in vivo activity in rodent ASD models. We discovered the development of this activity in the CA1 region of horizontal slices after prolonged interictal-like epileptiform activity in the CA3 region that was provoked by incubation in high potassium artificial cerebrospinal fluid. The CA1 epileptiform bursts were insensitive to blockers of glutamatergic transmission, and were carried by synaptic as well as extrasynaptic, tonically activated gamma-aminobutyric acid type A (GABA(A)) receptors. The bursts bear resemblance to in vivo gamma-oscillatory activity found in rat ASD models with respect to their gamma frequency spectrum, their origin (in the CA1), and their sensitivity to blockers of cation-chloride pumps (NKCC1 and KCC2), as well as to oxytocin. Considering this bursting activity as an in vitro model for studying comorbidity between epilepsy and ASD may help to disentangle the intricate interactions that underlie the comorbidity between both diseases and suggests that extrasynaptic tonic GABAergic transmission could represent a potential target for ASD
Integrated CO2 capture-fixation chemistry via interfacial ionic liquid catalyst in laminar gas/liquid flow
Simultaneous capture of carbon dioxide (CO2) and its utilization with subsequent work-up would significantly enhance the competitiveness of CO2-based sustainable chemistry over petroleum-based chemistry. Here we report an interfacial catalytic reaction platform for an integrated autonomous process of simultaneously capturing/fixing CO2 in gas-liquid laminar flow with subsequently providing a work-up step. The continuous-flow microreactor has built-in silicon nanowires (SiNWs) with immobilized ionic liquid catalysts on tips of cone-shaped nanowire bundles. Because of the superamphiphobic SiNWs, a stable gas-liquid interface maintains between liquid flow of organoamines in upper part and gas flow of CO2 in bottom part of channel. The intimate and direct contact of the binary reagents leads to enhanced mass transfer and facilitating reactions. The autonomous integrated platform produces and isolates 2-oxazolidinones and quinazolines-2,4(1H,3H)-diones with 81-97% yields under mild conditions. The platform would enable direct CO2 utilization to produce high-valued specialty chemicals from flue gases without pre-separation and work-up steps. ? 2017 The Author(s).1115Ysciescopu
SUSY GUTs under Siege : Proton Decay
SO(10) supersymmetric grand unified theories [SUSY GUTs] provide a beautiful
framework for physics beyond the standard model. Experimental measurements of
the three gauge couplings are consistent with unification at a scale GeV. In addition predictive models for fermion masses and
mixing angles have been found which fit the low energy data, including the
recent data for neutrino oscillations. SO(10) boundary conditions can be tested
via the spectrum of superparticles. The simplest models also predict neutron
and proton decay rates. In this paper we discuss nucleon decay rates and obtain
reasonable upper bounds. A clear picture of the allowed SUSY spectra as
constrained by nucleon decay is presented.Comment: 13 page
Higgs sector and R-parity breaking couplings in models with broken U(1)_B-L gauge symmetry
Four different supersymmetric models based on SU(2)_L X U(1)_R X U(1)_B-L and
SU(2)_L X SU(2)_R X U(1)_B-L gauge symmetry groups are studied. U(1)_B-L
symmetry is broken spontaneously by a vacuum expectation value (VEV) of a
sneutrino field. The right-handed gauge bosons may obtain their mass solely by
sneutrino VEV. The physical charged lepton and neutrino are mixtures of
gauginos, higgsinos and lepton interaction eigenstates. Explicit formulae for
masses and mixings in the physical lepton fields are found. The spontaneous
symmetry breaking mechanism fixes the trilinear R-parity breaking couplings.
Only some special R-parity breaking trilinear couplings are allowed. There is a
potentially large trilinear lepton number breaking coupling - which is unique
to left-right models - that is proportional to the SU(2)_R gauge coupling g_R.
The couplings are parametrized by few mixing angles, making the spontaneous
R-parity breaking a natural ``unification framework'' for R-parity breaking
couplings in SUSYLR models.Comment: 19 pages, no figures, uses REVTeX. To be published in PR
Remarks on the forces generated by two-neutrino exchange
A brief up-to-date review of the long range forces generated by two neutrino
exchange is presented. The potential due to exchange of a massive
neutrino-antineutrino pair between particles carrying weak charge might be
larger than expected if the neutrinos have not only masses but also magnetic
moments close to the present experimental bounds. It still remains too small to
be observable.Comment: 10 pages, 3 figures. One figure added. Accepted for publication in
EPJ
On the Spontaneous CP Breaking at Finite Temperature in a Nonminimal Supersymmetric Standard Model
We study the spontaneous CP breaking at finite temperature in the Higgs
sector in the Minimal Supersymmetric Standard Model with a gauge singlet. We
consider the contribution of the standard model particles and that of stops,
charginos, neutralinos, charged and neutral Higgs boson to the one-loop
effective potential. Plasma effects for all bosons are also included. Assuming
CP conservation at zero temperature, so that experimental constraints coming
from, {\it e.g.}, the electric dipole moment of the neutron are avoided, and
the electroweak phase transition to be of the first order and proceeding via
bubble nucleation, we show that spontaneous CP breaking cannot occur inside the
bubble mainly due to large effects coming from the Higgs sector. However,
spontaneous CP breaking can be present in the region of interest for the
generation of the baryon asymmetry, namely inside the bubble wall. The
important presence of very tiny explicit CP violating phases is also commented.Comment: 28 pages, 4 figures available upon request, DFPD 94/TH/38 and SISSA
94/81-A preprint
B --> Phi K_S and Supersymmetry
The rare decay B --> Phi K_S is a well-known probe of physics beyond the
Standard Model because it arises only through loop effects yet has the same
time-dependent CP asymmetry as B --> Psi K_S. Motivated by recent data
suggesting new physics in B --> Phi K_S, we look to supersymmetry for possible
explanations, including contributions mediated by gluino loops and by Higgs
bosons. Chirality-preserving LL and RR gluino contributions are generically
small, unless gluinos and squarks masses are close to the current lower bounds.
Higgs contributions are also too small to explain a large asymmetry if we
impose the current upper limit on B(B_s --> mu mu). On the other hand,
chirality-flipping LR and RL gluino contributions can provide sizable effects
and while remaining consistent with related results in B --> Psi K_S, Delta
M_s, B --> X_s gamma and other processes. We discuss how the LR and RL
insertions can be distinguished using other observables, and we provide a
string-based model and other estimates to show that the needed sizes of mass
insertions are reasonable.Comment: 33 pages, 32 figures, Updated version for PRD. Includes discussions
of other recent works on this topic. Added discussions & plots for gluino
mass dependence and effects of theoretical uncertaintie
Implications of LHC Searches on SUSY Particle Spectra: The pMSSM Parameter Space with Neutralino Dark Matter
We study the implications of LHC searches on SUSY particle spectra using flat
scans of the 19-parameter pMSSM phase space. We apply constraints from flavour
physics, g_mu-2, dark matter and earlier LEP and Tevatron searches. The
sensitivity of the LHC SUSY searches with jets, leptons and missing energy is
assessed by reproducing with fast simulation the recent CMS analyses after
validation on benchmark points. We present results in terms of the fraction of
pMSSM points compatible with all the constraints which are excluded by the LHC
searches with 1 fb^{-1} and 15 fb^{-1} as a function of the mass of strongly
and weakly interacting SUSY particles. We also discuss the suppression of Higgs
production cross sections for the MSSM points not excluded and contrast the
region of parameter space tested by the LHC data with the constraints from dark
matter direct detection experiments.Comment: 14 pages, 13 figures. v2: increased statistics, to appear in EPJ
Reconstructing Neutrino Properties from Collider Experiments in a Higgs Triplet Neutrino Mass Model
We extend the minimal supersymmetric standard model with bilinear R-parity
violation to include a pair of Higgs triplet superfields. The neutral
components of the Higgs triplets develop small vacuum expectation values (VEVs)
quadratic in the bilinear R-parity breaking parameters. In this scheme the
atmospheric neutrino mass scale arises from bilinear R-parity breaking while
for reasonable values of parameters the solar neutrino mass scale is generated
from the small Higgs triplet VEVs. We calculate neutrino masses and mixing
angles in this model and show how the model can be tested at future colliders.
The branching ratios of the doubly charged triplet decays are related to the
solar neutrino angle via a simple formula.Comment: 19 pages, 4 figures; one formula corrected, two author's names
corrected; some explanatory comments adde
Supersymmetry without R-parity : Constraints from Leptonic Phenomenology
R-parity conservation is an {\it ad hoc} assumption in the most popular
version of the supersymmetric standard model. Most studies of models which do
allow for R-parity violation have been restricted to various limiting
scenarios. The single-VEV parametrization used in this paper provides a
workable framework to analyze phenomenology of the most general theory of SUSY
without R-parity. We perform a comprehensive study of leptonic phenomenology at
tree-level. Experimental constraints on various processes are studied
individually and then combined to yield regions of admissible parameter space.
In particular, we show that large R-parity violating bilinear couplings are not
ruled out, especially for large .Comment: 56 pages Revtex with figures incorporated; typos (including
transcription typo in Table II) and minor corrections; proof-read version, to
appear in Phys. Rev.
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