In vitro evaluation of neutral oximes as reactivators of parathion-inhibited electric eel acetylcholinesterase

Organophosphorus (OP) compounds are irreversible inhibitors of acetylcholinesterase (AChE) commonly used as pesticides and, unfortunately, as nerve agents in terrorist attacks. These compounds are highly soluble easily crossing the blood-brain barrier (BBB). Clinically, oximes such as pralidoxime and obidoxime are used for the reactivation of AChE. These oximes are not sufficiently effective to reactivate AChE inhibited by different OPs besides the fact that they are permanently charged and do not readily cross the BBB. This work evaluated the ability of ten neutral oximes to reactivate parathion-inhibited eel AChE. Because oximes can bind to AChE as reversible inhibitors, this property was also evaluated, with pralidoxime (2-PAM) used as a reference compound. Unlike 2-PAM, which inhibited AChE in a concentration-dependent manner, neutral oximes were not good inhibitors of AChE. Neutral ligands can present affinity for the PAS site. Neutral oximes 1 and 2 (200 mM) reactivated parathion-inhibited eel AChE by 9% and 11%, respectively; but neither of them surpassed the reactivation efficacy of 2-PAM (25%). Neutral oximes 1 and 2 reactivated AChE at a safe concentration for humans. Both neutral oximes 1 and 2 are good non-quaternary moieties for the synthesis of conjugates with enhanced reactivation potency and BBB penetration

Thermal Casimir effect in ideal metal rectangular boxes

The thermal Casimir effect in ideal metal rectangular boxes is considered using the method of zeta functional regularization. The renormalization procedure is suggested which provides the finite expression for the Casimir free energy in any restricted quantization volume. This expression satisfies the classical limit at high temperature and leads to zero thermal Casimir force for systems with infinite characteristic dimensions. In the case of two parallel ideal metal planes the results, as derived previously using thermal quantum field theory in Matsubara formulation and other methods, are reproduced starting from the obtained expression. It is shown that for rectangular boxes the temperature-dependent contribution to the electromagnetic Casimir force can be both positive and negative depending on side lengths. The numerical computations of the scalar and electromagnetic Casimir free energy and force are performed for cubesComment: 10 pages, 4 figures, to appear in Europ. Phys. J.

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02