22 research outputs found
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Design concepts for a next generation light source at LBNL
The NGLS collaboration is developing design concepts for a multi-beamline soft x-ray FEL array powered by a superconducting linear accelerator, operating with a high bunch repetition rate of approximately 1 MHz. The CW superconducting linear accelerator design is based on developments of TESLA and ILC technology, and is supplied by an injector based on a high-brightness, highrepetition- rate photocathode electron gun. Electron bunches from the linac are distributed by RF deflecting cavities to the array of independently configurable FEL beamlines with nominal bunch rates of ∼100 kHz in each FEL, with uniform pulse spacing, and some FELs capable of operating at the full linac bunch rate. Individual FELs may be configured for different modes of operation, including self-seeded and external-laser-seeded, and each may produce high peak and average brightness x-rays with a flexible pulse format, and with pulse durations ranging from femtoseconds and shorter, to hundreds of femtoseconds. In this paper we describe current design concepts, and progress in RandD activities. Copyright © 2013 CC-BY-3.0 and by the respective authors
Monitoring disease activity in systemic lupus erythematosus with single-molecule array digital ELISA quantification of serum interferon-α
IF 7.873International audienceObjectivesNo simple or standardized assay is available to quantify interferon‐α (IFNα) in routine clinical practice. Single‐molecule–array (Simoa) digital enzyme‐linked immunosorbent assay (ELISA) technology enables direct IFNα quantification at fg/mL concentrations. This study was undertaken to assess IFNα digital ELISA diagnostic performances to monitor systemic lupus erythematosus (SLE) activity.MethodsIFNα concentrations in serum samples from 150 consecutive SLE patients in a cross‐sectional study were determined with digital ELISA and a functional biological activity assay (bioassay). According to their SELENA–SLEDAI flare composite, patients were divided into groups with inactive (SLEDAI 0), and into groups with no flare or mild/moderate flare or severe flare.ResultsBased on healthy blood donors, the abnormal serum‐IFNα level threshold value was 136 fg/mL. Next, using receiver operating characteristics curves for an SLE‐patient series, widely heterogeneous for disease activity and organ involvement, the threshold IFNα value associated with active disease was determined to be 266 fg/mL. The digital ELISA‐assessed serum‐IFNα level was a better biomarker of disease activity than the Farr test: its specificity, likelihood ratio for positive results and positive‐predictive value better discerned active SLE or flare from inactive patients. The digital ELISA was more sensitive than the bioassay to detect low‐abnormal serum‐IFNα concentrations and patients with low disease activity.ConclusionDirect serum‐IFNα determination with a highly sensitive assay might improve monitoring of clinical SLE activity and selection of the best candidates for anti‐IFNα treatment