An Integrated Circuit for Signal Processing of the AMS RICH Photmultipliers Tubes

An analog integrated circuit has been designed, in a BiCMOS 0.8 micron technology, for the feasability study of the signal processing of the AMS RICH photomultiplier tubes. This low power, three channel gated integrator includes its own gate and no external analog delay is requiered. It processes PMT pulses over a dynamic range of more than 100. A logic output that indicates whether the analog charge has to be considered is provided. This gated integrator is used with a compact DSP based acquisition system in a 132 channels RICH prototype. The charge calibration of each channel is carried out using a LED. The pedestal measurement is performed on activation of a dedicated input. The noise contribution study of the input RC network and amplifiers is presented.Comment: IEEE symp. on Nucl. Sci. and Med. Imaging, Toront

Accelerated X-ray Structure Elucidation of a 36 kDa Muramidase/Transglycosylase Using wARP

The X-ray structure of the 36kDa soluble lytic transglycosylase from Escherichia coli has been determined starting with the multiple isomorphous replacement method with inclusion of anomalous scattering at 2.7 Å resolution. Subsequently, before any model building was carried out, phases were extended to 1.7 Å, resolution with the weighted automated refinement procedure wARP, which gave a dramatic improvement in the phases. The electron-density maps from wARP were of outstanding quality for both the main chain and the side chains of the protein, which allowed the time spent on the tracing, interpretation and building of the X-ray structure to be substantially shortened. The structure of the soluble lyric transglycosylase was refined at 1.7 Å, resolution with X-PLOR to a final crystallographic R factor of 18.9%. Analysis of the wARP procedure revealed that the use of the maximum-likelihood refinement in wARP gave much better phases than least-squares refinement, provided that the ratio of reflections to protein atom parameters was approximately 1.8 or higher. Furthermore, setting aside 5% of the data for an Rfree test set had a negative effect on the phase improvement. The mean WwARP, a weight determined at the end of the wARP procedure and based on the variance of structure factors from six individually refined wARP models, proved to be a better indicator than the Rfree factor to judge different phase improvement protocols. The elongated Slt35 structure has three domains named the alpha, beta and core domains. The alpha domain contains mainly α-helices, while the beta domain consists of a five-stranded antiparallel β-sheet flanked by a short α-helix. Sandwiched between the alpha and beta domains is the core domain, which bears some resemblance to the fold of the catalytic domain of the previously elucidated 70 kDa soluble lytic transglycosylase from E. coli. The putative active site is at the bottom of a large deep groove in the core domain.

Beam induced heating of ferrite magnets

Alerted by impedance measurements of ferrite kicker magnets and by apparent beam induced pressure increase in the neighborhood of window frame kicker magnets, bench measurements of magnet heating have been done. They confirmed the necessity of interrupting the ferrite yoke. Another method, which can be applied for existing magnets, will be described. 1 ref., 4 figs

MCDA stakeholder workshops

Within the CONFIDENCE project, comprehensive methods have been developed for better support of decision making under uncertain conditions, mainly by use of Multi Criteria Decision Analysis (MCDA). While MCDA in general was available for use in the radiological crisis management community, no method of analysing uncertain conditions and supporting robust decision making under these conditions was available. During the CONFIDENCE project, the existing MCDA tool was improved and enhanced to deal with these requirements. For providing solid and reliable decision support for such a situation as a radiological emergency, the evaluation of decision-support tools by the stakeholders and their feedback is important, especially when considering their heterogeneous background caused by e.g. living in different countries. Therefore, several stakeholder panels in different countries were organized to include the end users’ opinions and to assure the usability of the final tool

The Opportunity of Point-of-Care Diagnostics in General Practice:Modelling the Effects on Antimicrobial Resistance

OBJECTIVES: Antimicrobial resistance (AMR) is a public health threat associated with antibiotic consumption. Community-acquired acute respiratory tract infections (CA-ARTIs) are a major driver of antibiotic consumption in primary care. We aimed to quantify the investments required for a large-scale rollout of point-of care (POC) diagnostic testing in Dutch primary care, and the impact on AMR due to reduced use of antibiotics. METHODS: We developed an individual-based model that simulates consultations for CA-ARTI at GP practices in the Netherlands and compared a scenario where GPs test all CA-ARTI patients with a hypothetical diagnostic strategy to continuing the current standard-of-care for the years 2020-2030. We estimated differences in costs and future AMR rates caused by testing all patients consulting for CA-ARTI with a hypothetical diagnostic strategy, compared to the current standard-of-care in GP practices. RESULTS: Compared to the current standard-of-care, the diagnostic algorithm increases the total costs of GP consultations for CA-ARTI by 9% and 19%, when priced at €5 and €10, respectively. The forecast increase in Streptococcus pneumoniae resistance against penicillins can be partly restrained by the hypothetical diagnostic strategy from 3.8 to 3.5% in 2030, albeit with considerable uncertainty. CONCLUSIONS: Our results show that implementing a hypothetical diagnostic strategy for all CA-ARTI patients in primary care raises the costs of consultations, while lowering antibiotic consumption and AMR. Novel health-economic methods to assess and communicate the potential benefits related to AMR may be required for interventions with limited gains for individual patients, but considerable potential related to antibiotic consumption and AMR

Study on intracranial meningioma using PET ligand investigation during follow-up over years (SIMPLIFY)

Purpose Radiologic follow-up of patients with a meningioma at the skull base or near the venous sinuses with magnetic resonance imaging (MRI) after stereotactic radiotherapy (SRT) and neurosurgical resection(s) can be difficult to interpret. This study evaluates the addition of C-11-methionine positron emission tomography (MET-PET) to the regular MRI follow-up. Methods This prospective pilot study included patients with predominantly WHO grade I meningiomas at the skull base or near large vascular structures. Previous SRT was part of their oncological treatment. A MET-PET in adjunct to their regular MRI follow-up was performed. The standardized uptake value (SUV) was determined for the tumor and the healthy brain, on the pre-SRT target delineation MET-PET and the follow-up MET-PET. Tumor-to-normal ratios were calculated, and C-11-methionine uptake over time was analyzed. Agreement between the combined MRI/MET-PET report and the MRI-only report was determined using Cohen's kappa. Results Twenty patients with stable disease underwent an additional MET-PET, with a median follow-up of 84 months after SRT. Post-SRT SUV T/N ratios ranged between 2.16 and 3.17. When comparing the pre-SRT and the post-SRT MET-PET, five categories of SUV T/N ratios did not change significantly. Only the SUVpeak T/N-cortex decreased significantly from 2.57 (SD 1.02) to 2.20 (SD 0.87) [p = 0.004]. A kappa of 0.77 was found, when comparing the MRI/MET-PET report to the MRI-only report, indicating no major change in interpretation of follow-up data. Conclusion In this pilot study, C-11-methionine uptake remained remarkably high in meningiomas with long-term follow-up after SRT. Adding MET-PET to the regular MRI follow-up had no impact on the interpretation of follow-up imaging