2,453 research outputs found
Light neutralino in the MSSM: An update with the latest LHC results
We discuss the scenario of light neutralino dark matter in the minimal
supersymmetric standard model, which is motivated by the results of some of the
direct detection experiments --- DAMA, CoGENT, and CRESST. We update our
previous analysis with the latest results of the LHC. We show that new LHC
constraints disfavour the parameter region that can reproduce the results of
DAMA and CoGENT.Comment: 4 pages, 4 figures, to appear in the conference proceedings of TAUP
2011, Munich Germany, 5-9 September 201
KCTD Hetero-oligomers confer unique kinetic properties on Hippocampal GABA B Receptor-Induced K + Currents
GABAB receptors are the G-protein coupled receptors for the main inhibitory neurotransmitter in the brain, GABA. GABAB receptors were shown to associate with homo-oligomers of auxiliary KCTD8, KCTD12, KCTD12b, and KCTD16 subunits (named after their T1 K+-channel tetramerization domain) that regulate G-protein signaling of the receptor. Here we provide evidence that GABAB receptors also associate with hetero-oligomers of KCTD subunits. Coimmunoprecipitation experiments indicate that two-thirds of the KCTD16 proteins in the hippocampus of adult mice associate with KCTD12. We show that the KCTD proteins hetero-oligomerize through self-interacting T1 and H1 homology domains. Bioluminescence resonance energy transfer measurements in live cells reveal that KCTD12/KCTD16 hetero-oligomers associate with both the receptor and the G-protein. Electrophysiological experiments demonstrate that KCTD12/KCTD16 hetero-oligomers impart unique kinetic properties on G-protein-activated Kir3 currents. During prolonged receptor activation (one min) KCTD12/KCTD16 hetero-oligomers produce moderately desensitizing fast deactivating K+ currents, whereas KCTD12 and KCTD16 homo-oligomers produce strongly desensitizing fast deactivating currents and nondesensitizing slowly deactivating currents, respectively. During short activation (2 s) KCTD12/KCTD16 hetero-oligomers produce nondesensitizing slowly deactivating currents. Electrophysiological recordings from hippocampal neurons of KCTD knock-out mice are consistent with these findings and indicate that KCTD12/KCTD16 hetero-oligomers increase the duration of slow IPSCs. In summary, our data demonstrate that simultaneous assembly of distinct KCTDs at the receptor increases the molecular and functional repertoire of native GABAB receptors and modulates physiologically induced K+ current responses in the hippocampus
The Effect of Dietary Fat on Behavior in Mice
Purpose Obesity is linked to cognitive dysfunction in humans and rodents, and its effects can be passed on to the next generation. However, the extent of these effects is not well understood. The purpose of this study was to determine the effect of a prenatal maternal high-fat diet and an individual high-fat diet in inbred mice. Methods We varied maternal diet and offspring diet to test the hypothesis that a high-fat diet would increase anxiety, reduce activity levels, and impair nest-building. First, we fed a high-fat (HF) or low-fat (LF) diet to genetically identical female Small (SM/J) mice and mated them with LF males. We cross-fostered all offspring to LF-fed SM/J nurses and weaned them onto an HF or LF diet. We weighed the mice weekly and we tested anxiety with the Open Field Test, activity levels with instantaneous scan sampling, and nest building using the Deacon Scale. Results Diet significantly affected weight, with HF females weighing 28.2 g (± 1.4 g SE) and LF females weighing 15.1 g (± 1.6 g SE) at 17 weeks old. The offspring’s own diet had major behavioral effects. HF mice produced more fecal boli and urinations in the Open Field Test, built lower-quality nests, and had lower activity in adulthood than LF mice. The only trait that a prenatal maternal diet significantly affected was whether the offspring built their nests inside or outside of a hut. Conclusions Offspring diet, but not prenatal maternal diet, affected a wide range of behaviors in these mice
The Semileptonic to Decays in QCD Sum Rules
We analyze the semileptonic rare decays of meson to and
axial vector mesons. The
decays are significant flavor changing neutral current decays of the meson.
These decays are sensitive to the new physics beyond SM, since these processes
are forbidden at tree level at SM. These decays occurring at the quark level
via transition, also provide new opportunities for
calculating the CKM matrix elements and . In this study, the
transition form factors of the decays
are calculated using three-point QCD sum rules approach. The resulting form
factors are used to estimate the branching fractions of these decays.Comment: 18 pages, 7 figures, version to appear in JP
Real-Time Treatment Planning Optimisation for Brachytherapy
In this paper, we present an integrated system for real-time dose distribution calculation and treatment planning optimisation for brachytherapy of prostate cancer, with a special emphasis on the visual integration of the dosimetry and target images obtained from the open magnetic resonance system. This system involves a fast method to calculate dose distributions of multiple concurrent radioactive sources, based on the combination of elements from a database of pre-calculated dose distribution maps for single sources, combined linearly to provide the final dose distribution map. Simulated annealing, in conjunction with the inverse planning method, is used to determine the source dwell times at pre-selected locations in order to optimally irradiate thetumour while preserving the surrounding healthy tissues. This algorithm, implemented in FORTRAN, is integrated into a computer-assisted treatment planning tool, written in JAVA, using the runtime class and RMI API of Java. The whole system is now under clinical testing at the Geneva University Hospital
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Search for lepton-flavour-violating decays of Higgs-like bosons.
A search is presented for a Higgs-like boson with mass in the range 45 to 195 GeV/c2 decaying into a muon and a tau lepton. The dataset consists of proton-proton interactions at a centre-of-mass energy of 8 TeV , collected by the LHCb experiment, corresponding to an integrated luminosity of 2 fb-1 . The tau leptons are reconstructed in both leptonic and hadronic decay channels. An upper limit on the production cross-section multiplied by the branching fraction at 95% confidence level is set and ranges from 22 pb for a boson mass of 45 GeV/c2 to 4 pb for a mass of 195 GeV/c2
GABAB receptor auxiliary subunits modulate Cav2.3-mediated release from medial habenula terminals
The synaptic connection from medial habenula (MHb) to interpeduncular nucleus (IPN) is critical for emotion-related behaviors and uniquely expresses R-type Ca2+ channels (Cav2.3) and auxiliary GABAB receptor (GBR) subunits, the K+-channel tetramerization domain-containing proteins (KCTDs). Activation of GBRs facilitates or inhibits transmitter release from MHb terminals depending on the IPN subnucleus, but the role of KCTDs is unknown. We therefore examined the localization and function of Cav2.3, GBRs, and KCTDs in this pathway in mice. We show in heterologous cells that KCTD8 and KCTD12b directly bind to Cav2.3 and that KCTD8 potentiates Cav2.3 currents in the absence of GBRs. In the rostral IPN, KCTD8, KCTD12b, and Cav2.3 co-localize at the presynaptic active zone. Genetic deletion indicated a bidirectional modulation of Cav2.3-mediated release by these KCTDs with a compensatory increase of KCTD8 in the active zone in KCTD12b-deficient mice. The interaction of Cav2.3 with KCTDs therefore scales synaptic strength independent of GBR activation
Lack of functional GABA receptors alters Kiss1 , Gnrh1 and Gad1 mRNA expression in the medial basal hypothalamus at postnatal day 4
Background/Aims: Adult mice lacking functional GABAB receptors (GABAB1KO) show altered Gnrh1 and Gad1 expressions in the preoptic area-anterior hypothalamus (POA-AH) and females display disruption of cyclicity and fertility. Here we addressed whether sexual differentiation of the brain and the proper wiring of the GnRH and kisspeptin systems were already disturbed in postnatal day 4 (PND4) GABAB1KO mice. Methods: PND4 wild-type (WT) and GABAB1KO mice of both sexes were sacrificed; tissues were collected to determine mRNA expression (qPCR), amino acids (HPLC), and hormones (RIA and/or IHC). Results: GnRH neuron number (IHC) did not differ among groups in olfactory bulbs or OVLT-POA. Gnrh1 mRNA (qPCR) in POA-AH was similar among groups. Gnrh1 mRNA in medial basal hypothalamus (MBH) was similar in WTs but was increased in GABAB1KO females compared to GABAB1KO males. Hypothalamic GnRH (RIA) was sexually different in WTs (males < females), but this sex difference was lost in GABAB1KOs; the same pattern was observed when analyzing only the MBH, but not in the POA-AH. Arcuate nucleus Kiss1 mRNA (micropunch-qPCR) was higher in WT females than in WT males and GABAB1KO females. Gad1 mRNA in MBH was increased in GABAB1KO females compared to GABAB1KO males. Serum LH and gonadal estradiol content were also increased in GABAB1KOs. Conclusion: We demonstrate that GABABRs participate in the sexual differentiation of the ARC/MBH, because sex differences in several reproductive genes, such as Gad1, Kiss1 and Gnrh1, are critically disturbed in GABAB1KO mice at PND4, probably altering the organization and development of neural circuits governing the reproductive axis. (c) 2013 S. Karger AG, Basel
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