Sleep misperception is often observed in insomnia individuals (INS). The extent of misperception varies between different types of INS. The following paper comprised sections which will be aimed at ...studying the sleep EEG and compares it to subjective reports of sleep in individuals suffering from either psychophysiological insomnia or paradoxical insomnia and good sleeper controls. The EEG can be studied without any intervention (thus using the raw data) via either PSG or fine quantitative EEG analyses (power spectral analysis PSA), identifying EEG patterns as in the case of cyclic alternating patterns (CAPs) or by decorticating the EEG while scoring the different transient or phasic events (K-Complexes or sleep spindles). One can also act on the on-going EEG by delivering stimuli so to study their impact on cortical measures as in the case of event-related potential studies (ERPs). From the paucity of studies available using these different techniques, a general conclusion can be reached: sleep misperception is not an easy phenomenon to quantify and its clinical value is not well recognized. Still, while none of the techniques or EEG measures defined in the paper is available and/or recommended to diagnose insomnia, ERPs might be the most indicated technique to study hyperarousal and sleep quality in different types of INS. More research shall also be dedicated to EEG patterns and transient phasic events as these EEG scoring techniques can offer a unique insight of sleep misperception.
La mésestimation du sommeil est souvent observée chez les individus souffrant d’insomnie (INS). Cependant, l’ampleur de cette mésestimation varie entre les types d’INS. Cet article est composé de sections dédiées à l’étude de l’EEG et sa comparaison avec les rapports subjectifs de sommeil d’individus souffrant soit d’insomnie psychophysiologique ou paradoxale et bons dormeurs. L’EEG peut être étudié soit sans intervention (en utilisant les données brutes) comme dans le cas de la polysomnographie ou l’analyse spectrale, soit en identifiant des patrons d’activation comme pour les patrons cycliques alternants (cyclic alternating pattern) ou encore en décortiquant l’EEG en évènements phasiques ou transitoires (complexes-K et fuseaux de sommeil). On peut également agir sur l’EEG en délivrant des sons et en étudiant leur impact sur les ondes de l’EEG comme dans le cas des potentiels évoqués, et surtout ceux cognitifs. Du peu d’études disponibles utilisant ces différentes techniques/mesures, une conclusion générale peut tout de même être tirée : la mésestimation du sommeil n’est pas facilement quantifiable et sa valeur clinique n’est pas adéquatement reconnue. Alors qu’aucune des techniques/mesures définies ici n’est disponible ou recommandée afin de diagnostiquer l’insomnie, la technique utilisant les potentiels évoqués cognitifs semble la plus appropriée ou juste afin de mesurer l’hypervigilance corticale (hyperarousal) et la qualité du sommeil chez les différents types d’individus souffrant d’insomnie. Finalement, plus de recherches devraient être dédiées à l’étude des patrons EEG et des évènements phasiques du sommeil puisque ces techniques apportent une compréhension différemment unique de la mésestimation du sommeil.
LHCb calorimeters high voltage system Gilitsky, Yu; Golutvin, A.; Konoplyannikov, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2007, Letnik:
571, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The calorimeter system in LHCb aims to identify electrons, photons and hadrons. All calorimeters are equipped with Hamamatsu photo tubes as devices for light to signal conversion. Eight thousand ...R7899-20 tubes are used for electromagnetic and hadronic calorimeters and two hundred 64 channels multi-anode R7600-00-M64 for Scintillator-Pad/Preshower detectors. The calorimeter high voltage (HV) system is based on a Cockroft Walton (CW) voltage converter and a control board connected to the Experiment Control System (ECS) by serial bus. The base of each photomultiplier tube (PMT) is built with a high voltage converter and constructed on an individual printed circuit board, using compact surface mount components. The base is attached directly to the PMT. There are no HV cables in the system. A Field Programmable Gate Array (FPGA) is used on the control board as an interface between the ECS and the 200 control channels. The FPGA includes also additional functionalities allowing automated monitoring and ramp up of the high voltage values. This paper describes the HV system architecture, some technical details of the electronics implementation and summarizes the system performance. This safe and low power consumption HV electronic system for the photomultiplier tubes can be used for various biomedical apparatus too.
Repair of DNA double strand breaks (DSBs) by the non-homologous end joining (NHEJ) pathway in mammals requires at least the DNA-dependent protein kinase (DNA-PK) and the DNA ligase IV-XRCC4 protein ...complexes. DNA-PK comprises the Ku70/Ku80 heterodimer and the catalytic subunit DNA-PKcs. Here we report the first description of the nuclear mobilization of endogenous NHEJ proteins after exposure of human cells to double strand-breaking agents. DSB infliction specifically induced a dose- and time-dependent mobilization of Ku70/80, DNA-PKcs, XRCC4, and DNA ligase IV proteins from a soluble nucleoplasmic compartment to a less extractable nuclear fraction. XRCC4 recruitment was accompanied by its DNA-PK-dependent phosphorylation. The recruited proteins co-immunoprecipitated, indicating that they had assembled into complexes. However, DNA-PK was attached to chromatin, whereas XRCC4-ligase IV resisted solubilization by DNase I. The rates of appearance and dissolution of NHEJ proteins paralleled that of histone variant H2AX phosphorylation and dephosphorylation. We established that under conditions of genomic DSB infliction 1) Ku recruitment was not dependent on the co-recruitment of the other NHEJ proteins, 2) DNA-PKcs was physically required for the mobilization of the XRCC4-ligase IV complex, 3) DNA ligase IV was physically necessary for stable recruitment of XRCC4, and 4) phosphorylation of either H2AX or XRCC4 was unnecessary for DNA-PK or XRCC4-ligase IV recruitment. Altogether these results offer insights into the interplay between key NHEJ proteins during this repair process in the cell.
The current mode line terminating input stage of an integrated circuit for the upgrade of the LHCb calorimeter front end electronics is presented. The circuit is based on a current mode input stage ...followed by two fully differential interleaved channels, namely a switched integrator and a track and hold. The input stage employs a novel electronically cooled input termination scheme to achieve stringent noise requirements. Compared to previous designs, its novelty relies in the use of two current feedback loops to decrease and control the input impedance of a common base stage. Two prototypes in Austriamicrosystems SiGe BiCMOS 0.35 μm technology have been designed and tested. Key measurements have been performed. Reflection coefficient is smaller than 0.5% for the full dynamic range, which is 12 bits. Relative linearity error is below 1%. Output noise is about 1 LSB after applying correlated double sampling.
Bar presses by one group of rats were conditioned under a differential‐reinforcement‐of‐low‐rate reinforcement schedule immediately prior to conditioning under a fixed‐interval schedule. In a second ...group of rats, bar presses were conditioned first under a differential‐reinforcement‐of‐low‐rate schedule and then under a fixed‐ratio schedule prior to conditioning under a fixed‐interval schedule. Low response rates occurred under the fixed‐interval schedule only when it was immediately preceded by low‐rate conditioning. Otherwise, fixed‐interval responding was similar to responding under the fixed‐ratio schedule. This finding suggests that responses of laboratory animals are sensitive to immediate history, and, unlike human responses, are relatively insensitive to a history of low‐rate conditioning when it is followed by high‐rate conditioning.
PDF
