0000000000655045
AUTHOR
F. Bartels
Performance of the upgraded PreProcessor of the ATLAS Level-1 Calorimeter Trigger
The PreProcessor of the ATLAS Level-1 Calorimeter Trigger prepares the analogue trigger signals sent from the ATLAS calorimeters by digitising, synchronising, and calibrating them to reconstruct transverse energy deposits, which are then used in further processing to identify event features. During the first long shutdown of the LHC from 2013 to 2014, the central components of the PreProcessor, the Multichip Modules, were replaced by upgraded versions that feature modern ADC and FPGA technology to ensure optimal performance in the high pile-up environment of LHC Run 2. This paper describes the features of the newMultichip Modules along with the improvements to the signal processing achieved.
Observation and Measurement of Forward Proton Scattering in Association with Lepton Pairs Produced via the Photon Fusion Mechanism at ATLAS
The observation of forward proton scattering in association with lepton pairs (eþe− þ p or μþμ− þ p) produced via photon fusion is presented. The scattered proton is detected by the ATLAS Forward Proton spectrometer, while the leptons are reconstructed by the central ATLAS detector. Proton-proton collision data recorded in 2017 at a center-of-mass energy of ffiffiffi s p ¼ 13 TeV are analyzed, corresponding to an integrated luminosity of 14.6 fb−1. A total of 57 (123) candidates in the ee þ p (μμ þ p) final state are selected, allowing the background-only hypothesis to be rejected with a significance exceeding 5 standard deviations in each channel. Proton-tagging techniques are introduced f…
Activation and Inactivation of Tetanus Toxin in Chromaffin Cells
Tetanus toxin is produced by Clostridium tetani as a single chain, almost non-toxic, protein with a molecular weight of approximately 150.000 representing 1315 amino acids. Bacterial proteases cleave the molecule between positions A 457 and S 458 (extracellular activation), yielding a heavy chain (MW 100.000) and a light chain (MW 50.000) tetanus toxin (HC-TeTx, LC-TeTx). Both chains remain connected to each other by a disulphur bond between positions C 439 and C 467 (Dichain-TeTx)1. The cleavage or nicking dramatically increases the biological activity2. HC-TeTx is involved in binding DC-TeTx to gangliosides lodged in the plasma membrane, which is a prerequisite for incorporation into the …
Processing of tetanus and botulinum A neurotoxins in isolated chromaffin cells.
Tetanus and botulinum A neurotoxins were introduced into the cytosol of chromaffin cells by means of an electric field in which the plasma membrane is forced to form pores of approximately 1 micron at the sites facing the electrodes. As demonstrated by electron microscopy, both [125I] and gold-labelled tetanus toxin (TeTx) diffuse through these transient openings. Dichain-TeTx, with its light chain linked to the heavy chain by means of a disulfide bond, causes the block of exocytosis to develop more slowly than does the purified light chain. The disulfide bonds, which in both toxins hold the subunits together, were cleaved by the intrinsic thioredoxin-reductase system. Single chain TeTx, in…