We are developing a positron emission tomography (PET) insert for existing magnetic resonance (MR) equipment, aiming at hybrid MR–PET imaging. Our detector block design is based on trapezoid-shaped ...LYSO:Ce monolithic scintillators coupled to magnetically compatible Hamamatsu S8550-02 silicon avalanche photodiode (APD) matrices with a dedicated ASIC front-end readout from GammaMedica-Ideas (Fornebu, Norway). The detectors are position sensitive, capable of determining the incidence point of 511keV gammas with an intrinsic spatial resolution on the order of 2mm by means of supervised learning neural-network (NN) algorithms. These algorithms, apart from providing continuous coordinates, are also intrinsically corrected for depth of interaction effects and thus parallax-free. Recently we have implemented an advanced prototype featuring two heads with four detector blocks each and final front-end and readout electronics, improving the spatial resolution of reconstructed point source images down to 1.7mm full width at half maximum (FWHM). Presently we are carrying out operational tests of components and systems under magnetic fields using a 3 T MR scanner. In this paper we present a description of our project, a summary of the results obtained with laboratory prototypes, and the strategy to build and install the complete system at the nuclear medicine department of a collaborating hospital.
To investigate outcome in children with mild traumatic head injury (THI) at 1 week and 3 months postinjury and to identify factors associated with persisting problems.
Postconcussional ...symptomatology, behavior ratings, and neuropsychological test performance were examined at 1 week and 3 months postinjury.
Participants were recruited from successive presentations to emergency departments of two major hospitals.
130 Children with mild THI were compared with 96 children having other minor injuries as controls.
Children with mild THI experienced headaches, dizziness, and fatigue but exhibited no cognitive impairments, relative to controls, at 1 week postinjury. By 3 months, symptoms had resolved. However, 17% of children showed significant ongoing problems. They were more likely to have a history of previous head injury, learning difficulties, neurological or psychiatric problems, or family stressors.
Persisting problems following mild head injury in children are more common in those with previous head injury, preexisting learning difficulties, or neurological, psychiatric, or family problems. These "at-risk" children should be identified in the emergency department and monitored.
Two "smart" interpolation procedures are presented and assessed with respect to their ability to estimate annual-average air temperatures at unsampled points in space from available station averages. ...Smart approaches examined here improve upon commonly used procedures in that they incorporate spatially high-resolution digital elevation information, an average environmental lapse rate, and/or another higher-resolution longer-term average temperature field. Two other straightforward or commonly used interpolation methods also are presented and evaluated as benchmarks to which the smart interpolators can be compared. Interpolation from a spatially high-resolution, long-term-average air temperature climatology serves as a first approximation, while "traditional" interpolation (from a single realization of annual average air temperature on a single station network) is the other benchmark. Traditional interpolation continues to be the most commonly used interpolation approach within many of the atmospheric and environmental sciences. Smart approaches are significantly more accurate than either traditional methods or estimates spatially interpolated from a high-resolution climatology alone. A smart interpolation method that makes combined use of a digital elevation model (DEM) and traditional interpolation was nearly 24% more accurate than traditional interpolation by itself. Average error associated with this DEM-assisted interpolation algorithm, for interpolating yearly average air temperatures in the United States, was 0.44°C. The other smart method that was evaluated combines DEM information with a high-resolution average air temperature field. It was even more accurate, as expressed in an overall average interpolation error of only 0.38°C per year, which makes it some 34% more accurate than traditional interpolation. It is likely that the performance of smart interpolation, relative to traditional interpolation, will be even better when used with relatively sparse station networks.
Several irradiation tests of the electronics of the CMS barrel muon detector were performed using neutrons, protons and heavy ions. The Single Event Upset rate on some tested devices was measured, ...while upper limits were obtained for devices having experienced no failure. Single Event Transients on front-end electronics and destructive effects on the High-voltage distribution electronics were observed. Overcurrent protection and error correction circuits were included in the irradiated boards and were tested.
Study objective: Duration of post-traumatic amnesia (PTA) is an important index of severity of head injury. Retrospective assessment of PTA duration is arguably unreliable. Existing objective ...measures of PTA duration are designed for use over a 24-hour timeframe and, therefore, are not useful for assessing PTA following mild head injury (MHI). A revised version of the Westmead PTA scale was developed for assessing patients with MHI in the Emergency Department (ED) at hourly intervals. The objective of this study was the field testing of this scale in EDs and assessment of validity and reliability of test items.
Methods: The scale contained 12 items, assessing orientation, memory for a face and name in a photograph and three pictures of objects. This revised scale, administered by nursing staff, was completed at least four times at hourly intervals by 147 adults with MHI in the ED and again at follow-up 1 week later. It was also completed by 109 demographically similar controls. Results were compared with Glasgow Coma scores and retrospective estimates of PTA duration based on patient report and medical records.
Results: Thirty-six per cent of MHI participants made errors on the scale in the ED, a significantly greater proportion than in MHI or controls at follow-up. Removal of the items 5 (day of week) and 9 (recall of name of face in photograph) improved the validity of the measure significantly. Scores correlated significantly with Glasgow Coma Scale scores and estimated duration of PTA.
Conclusion: The Westmead Scale (minus items 5 and 9) is a valid measure of PTA duration in adult patients with MHI in ED. Its use will allow for more appropriate timing of discharge and accurate prognostic information.
On the CMS experiment for LHC collider at CERN, the drift tube chambers (DT's) are responsible of muon detection and precise momentum measurement. Described in this paper is the first level of the ...read out electronics for these DT chambers that will be located inside the muon barrel detector in the so-called minicrates (MC), attached to the chambers. The read out boards (ROB) are the main component of this first level data acquisition system, and they are in charge of the time digitalization related to level 1 accept trigger of the incoming signals from the front-end electronics, following a consequent data merging to next stages of the data acquisition chain. Its architecture and functionality has been exhaustively tested, as well as its capability of operation beyond the expected environmental and radiation conditions inside the CMS detector. The satisfactory results obtained have allowed to proceed with ROB final production and its assembly in the MCs. A total amount of 250 MCs and around 1500 ROBs are being produced and tested thoroughly at CIEMAT (Spain), including burn-in tests for guaranteeing ten years of limited maintenance operation. An overview of the system and a summary of the different results of the tests performed on ROB's and MC will be presented. They include acceptance tests for the production chain as well as some validation tests that insured proper operation of the ROB's beyond the CMS detector conditions.
The second level trigger (LV2) system of the FAST detector is described in this paper. The fiber active scintillator target (FAST) is an imaging particle detector intended for muon lifetime ...measurement with a precision of 1 ppm. The aim of the trigger system is to reduce the data throughput that the data acquisition (DAQ) chain must handle to make the experiment able to run with a first level trigger rate of 1 MHz. The electronic system is being designed at CIEMAT (Madrid, Spain). A first prototype was developed and satisfactory results have been obtained under beam operation conditions.
The effects of DNA gyrase and quinolone drugs on in vitro transcription of a template containing a preferred gyrase cleavage site have been investigated. We have found that gyrase-quinolone complexes ...with DNA lead to blocking of transcription by Escherichia coli and bacteriophage T7 RNA polymerases. Either gyrase or quinolone alone has no effect on transcription. With DNA gyrase containing a point mutation in the gyrase A protein, known to confer quinolone resistance, blocking was found to occur only at much higher concentrations of the drug. Other agents that inhibit gyrase-catalysed supercoiling (novobiocin and 5'-adenylyl-beta,gamma-imidodiphosphate) do not arrest transcription in the presence of gyrase. Mapping of the transcription termination sites in the presence of gyrase and quinolones shows that blocking occurs about 10 to 20 base-pairs upstream of the gyrase cleavage site. Analysis of transcription in the absence of drug suggests that RNA polymerase does not displace gyrase from the template. These results are discussed in the light of models for the bactericidal effects of quinolone drugs.
