PicoTesla absolute field readings with a hybrid 3He/87Rb magnetometer

We demonstrate the use of a hybrid 3He/87 magnetometer to measure absolute magnetic fields in the pT range. The measurements were undertaken by probing time-dependent 3He magnetisation using 87Rb zero-field magnetometers. Measurements were taken to demonstrate the use of the magnetometer in cancelling residual fields within a magnetic shield. It was shown that the absolute field could be reduced to the 10 pT level by using field readings from the magnetometer. Furthermore, the hybrid magnetometer was shown to be applicable for the reduction of gradient fields by optimising the effective 3He T2 time. This procedure represents a convenient and consistent way to provide a near zero magnetic field environment which can be potentially used as a base for generating desired magnetic field configurations for use in precision measurements

GABAA and glycine receptor-mediated transmission in rat lamina II neurones: relevance to the analgesic actions of neuroactive steroids

Analgesic neurosteroids such as 5-pregnan-3-ol-20-one (53) are potent selective endogenous modulators of the GABAA receptor (GABAAR) while certain synthetic derivatives (i.e. minaxolone) additionally enhance the function of recombinant glycine receptors (GlyR). Inhibitory transmission within the superficial dorsal horn has been implicated in mediating the analgesic actions of neurosteroids. However, the relative contribution played by synaptic and extrasynaptic receptors is unknown. In this study, we have compared the actions of 53 and minaxolone upon inhibitory transmission mediated by both GABAA and strychnine-sensitive GlyRs in lamina II neurones of juvenile (P15-21) rats. At the near physiological temperature of 35°C and at a holding potential of -60 mV we recorded three kinetically distinct populations of miniature IPSCs (mIPSCs): GlyR-mediated, GABAAR-mediated and mixed GABAAR-GlyR mIPSCs, arising from the corelease of both inhibitory neurotransmitters. In addition, sequential application of strychnine and bicuculline revealed a small (5.2 ± 1.0 pA) GlyR- but not a GABAAR-mediated tonic conductance. 53 (1-10 µM) prolonged GABAAR and mixed mIPSCs in a concentration-dependent manner but was without effect upon GlyR mIPSCs. In contrast, minaxolone (1-10 µM) prolonged the decay of GlyR mIPSCs and, additionally, was 10-fold more potent than 53 upon GABAAR mIPSCs. However, 53 and minaxolone (1 µM) evoked a similar bicuculline-sensitive inhibitory conductance, indicating that the extrasynaptic GABAARs do not discriminate between these two steroids. Furthermore, 92% of the effect of 1 µM 53 upon GABAergic inhibition could be accounted for by its action upon the extrasynaptic conductance. These findings are relevant to modulation of inhibitory circuits within spinally mediated pain pathways and suggest that extrasynaptic GABAARs may represent a relevant molecular target for the analgesic actions of neurosteroids

The search for \ub5+ \u2192 e+\u3b3 with 10 1214 sensitivity: The upgrade of the meg experiment

The MEG experiment took data at the Paul Scherrer Institute in the years 2009\u20132013 to test the violation of the lepton flavor conservation law, which originates from an accidental symmetry that the Standard Model of elementary particle physics has, and published the most stringent limit on the charged lepton flavor violating decay \ub5+ \u2192 e+\u3b3: BR(\ub5+ \u2192 e+\u3b3) < 4.2 7 10 1213 at 90% confidence level. The MEG detector has been upgraded in order to reach a sensitivity of 6 7 10 1214 . The basic principle of MEG II is to achieve the highest possible sensitivity using the full muon beam intensity at the Paul Scherrer Institute (7 7 107 muons/s) with an upgraded detector. The main improvements are better rate capability of all sub-detectors and improved resolutions while keeping the same detector concept. In this paper, we present the current status of the preparation, integration and commissioning of the MEG II detector in the recent engineering runs

Erratum to: Data blinding for the nEDM experiment at PSI

ISSN:1434-6001ISSN:1434-601