Assessing Scrubbing Techniques for Xilinx SRAM-based FPGAs in Space Applications

SRAM-based FPGAs are becoming increasingly attractive for use in space applications due to their reconfigurability and signal processing capabilities, as well as their increasing speed and capacity. Traditional SRAM-based FPGAs, however, are highly sensitive to the ionizing radiation environment in space, making them prone to radiation-induced memory upsets. In this paper, we evaluate and compare scrubbing techniques for Xilinx SRAM-based FPGAs with respect to radiation-induced single event upsets. A test framework using an exchangeable payload is developed for this purpose and run on a Xilinx Virtex-5 FPGA. We show that recent SRAM-based FPGAs can constitute a cost-efficient alternative to radiation-hardened or antifuse FPGAs for non-critical space application such as satellite instruments

Boganmeldelser

Intet resum

Radiographic progression in PsA Personal non-commercial use only

ABSTRACT. Objective. To describe early radiographic findings in patients from the Swedish psoriatic arthritis (SwePsA) registry, progression of destruction, correlations with clinical disease variables, and predictors of destruction. Methods. Hand and foot radiographs were available for 72 of 197 SwePsA patients followed for 5 years. Clinical data were collected according to the SwePsA protocol. Results. Disease characteristics and clinical improvement were similar in men and women. Radiographic abnormalities were more pronounced in men. Total Wassenberg radiographic score at baseline was 0 in 45% of men and 51% of women. One man and one woman had a score > 10. At 5 years, total score was 0 in 14% of men and 40% of women (p = 0.018); 17% of men and 7% of women had scores > 10. Mean total scores for men and women had increased. Baseline erythrocyte sedimentation rate was associated with baseline total radiographic score. In men, swollen joint count was positively, and in women tender joint count negatively, correlated to total radiographic score. After 5 years, only male scores, mainly hand scores, significantly correlated with 28-joint Disease Activity Score and Disease Activity Index for Psoriatic Arthritis scores, swollen joint count, and dactylitis. Achieving remission or minimal disease activity after 5 years protected against structural damage, mainly in men. Conclusion. Radiographic progression in early PsA was generally slow but substantial. Male sex appears to be a risk factor for early radiographic damage while the presence of baseline radiographic damage and dactylitis developing during followup seem to predict further destruction. Hand and foot radiograph scoring cannot be substituted with clinical signs. (J Rheumatol First Release October 15 2015; doi:10.3899/jrheum.150165

Visual grading evaluation of commercially available metal artefact reduction techniques in hip prosthesis computed tomography

Objectives: To evaluate metal artefact reduction (MAR) techniques from four computed tomography (CT) vendors in hip prosthesis imaging. Methods: Bilateral hip prosthesis phantom images, obtained by using MAR algorithms for single energy CT data or dual energy CT (DECT) data and by monoenergetic reconstructions of DECT data, were visually graded by five radiologists using ten image quality criteria. Comparisons between the MAR images and a reference image were performed for each scanner separately. Ordinal probit regression analysis was used. Results: The MAR algorithms in general improved the image quality based on the majority of the criteria (up to between 8/10 and 10/10) with a statistically improvement in overall image quality (P<0.001). However, degradation of image quality, such as new artefacts, was seen in some cases. A few monoenergetic reconstruction series improved the image quality (P<0.004) for one of the DECT scanners, but it was only improved for some of the criteria (up to 5/10). Monoenergetic reconstructions resulted in worse image quality for the majority of the criteria (up to 7/10) for the other DECT scanner. Conclusions: The MAR algorithms improved the image quality of the hip prosthesis CT images. However, since additional artefacts and degradation of image quality were seen in some cases, all algorithms should be carefully evaluated for every clinical situation. Monoenergetic reconstructions were in general concluded to be insufficient for reducing metal artifacts. Advances in knowledge: Qualitative evaluation of the usefulness of several MAR techniques from different vendors in CT imaging of hip prosthesis

Increased carotid intima-media thickness in patients with radiographic axial spondyloarthritis compared to controls and associations with markers of inflammation

Objective: There is an increased risk for cardiovascular disease (CVD) in patients with radiographic axial spondyloarthritis (r-axSpA). In this cross-sectional study, we aimed to, overall and stratified by sex, (i) compare ultrasound derived carotid intima media thickness (cIMT), between patients and controls, and (ii) investigate associations between cIMT, clinical disease activity and inflammation-related laboratory markers in patients with r-axSpA. Method: In total, 155 patients diagnosed with r-axSpA using the modified New York criteria and 400 controls were included. Bilateral carotid ultrasound, laboratory testing, and questionaries were acquired. Disease-specific assessments were carried out for patients. Linear regression analysis was used to assess associations. Results: Linear regression analyses showed that patients with r-axSpA had increased mean cIMT compared to controls (mean ± SD, 0.8 ± 0.1 mm vs 0.7± 0.1 mm, respectively, unstandardized β (95% CI) -0.076 (-0.10, -0.052), P < 0.001) adjusted for smoking status and age. Linear regression analyses for patients with r-axSpA showed that only males presented significant associations between cIMT and inflammation-related laboratory markers, white blood cell (WBC) count (mean ± SD, 6.8 ± 1.6 109/L) and monocytes (0.6 ± 0.2 109/L); WBC count (unstandardized β (95% CI) 0.019 (0.0065, 0.031), P = 0.003, R2 = 0.57) and monocytes (0.13 (0.0047, 0.26), P = 0.041, R2 = 0.55), adjusted for age, smoking status, body mass index, hypertension, dyslipidemia, diabetes mellitus, ASDAS-CRP, and treatment with DMARDs and glucocorticoids. No significant association was found between cIMT and clinical disease activity assessed by ASDAS-CRP. Conclusion: Patients with r-axSpA had significantly increased cIMT compared to controls. In male patients, higher WBC and monocyte count were associated with an increase in cIMT suggesting the role of inflammation in the development of atherosclerosis.