The Detection of Defects in a Niobium Tri-layer Process

Niobium (Nb) LTS processes are emerging as the technology for future ultra high-speed systems especially in the digital domain. As the number of Josephson Junctions (JJ) per chip has recently increased to around 90000, the quality of the process has to be assured so as to realize these complex circuits. Until now, very little or no information is available in the literature on how to achieve this. In this paper we present an approach and results of a study conducted on an RSFQ process. Measurements and SEM inspection were carried out on sample chips and a list of possible defects has been identified and described in detail. We have also developed test-structures for detection of the top-ranking defects, which will be used for yield analysis and the determination of the probability distribution of faults in the process. A test chip has been designed, based on the results of this study, and certain types of defects were introduced in the design to study the behavior of faulty junctions and interconnections

Optimization of nodule management in CT lung cancer screening

Lung cancer is the leading cancer-related cause of death. Through computed tomography (CT) screening, cancer can be detected at the earliest stage, with a much greater probability of cure. After the positive outcome of the US National Lung Screening Trial (NLST), screening with low-dose CT in heavy (former) smokers is now being implemented in the US. An important disadvantage of this study, however, is the high number of false-positive screening results, about 27%, meaning that many individuals without lung cancer suffer from unnecessary follow-up scans, invasive investigations with complication risk, and fear of cancer. The Dutch-Belgian NELSON study used a screening protocol based on lung nodule volume, rather than diameter (NLST), and on growth rate expressed as volume-doubling time (VDT). This approach yields 10x fewer false-positive screening results and a better cancer detection rate. The aim of this thesis was to examine how the percentage of false-positive results can be reduced even further while maintaining reliable cancer detection. Management of screening-detected lung nodules can be optimized by semi-automatic volume measurements instead of manual diameter measurements: VDT can reliably quantify nodule growth, and optimized cut-off values for nodule volume and VDT can distinguish between negative, intermediate and positive screening results. For new nodules, more stringent guidelines are needed. Ultimately, the interpretation by the radiologist, who can deviate from the screening protocol, remains important to further improve the results. Mortality analysis of the NELSON trial is essential to decide whether lung cancer screening in Europe should be implemented (cite Editorial Lancet)

Analysis of the spatial variation in the parameters of the SWAT model with application in Flanders, Northern Belgium

International audienceOperational applications of a hydrological model often require the prediction of stream flow in (future) time periods without stream flow observations or in ungauged catchments. Data for a case-specific optimisation of model parameters are not available for such applications, so parameters have to be derived from other catchments or time periods. It has been demonstrated that for applications of the SWAT in Northern Belgium, temporal transfers of the parameters have less influence than spatial transfers on the performance of the model. This study examines the spatial variation in parameter optima in more detail. The aim was to delineate zones wherein model parameters can be transferred without a significant loss of model performance. SWAT was calibrated for 25 catchments that are part of eight larger sub-basins of the Scheldt river basin. Two approaches are discussed for grouping these units in zones with a uniform set of parameters: a single parameter approach considering each parameter separately and a parameter set approach evaluating the parameterisation as a whole. For every catchment, the SWAT model was run with the local parameter optima, with the average parameter values for the entire study region (Flanders), with the zones delineated with the single parameter approach and with the zones obtained by the parameter set approach. Comparison of the model performances of these four parameterisation strategies indicates that both the single parameter and the parameter set zones lead to stream flow predictions that are more accurate than if the entire study region were treated as one single zone. On the other hand, the use of zonal average parameter values results in a considerably worse model fit compared to local parameter optima. Clustering of parameter sets gives a more accurate result than the single parameter approach and is, therefore, the preferred technique for use in the parameterisation of ungauged sub-catchments as part of the simulation of a large river basin. Keywords: hydrological model, regionalisation, parameterisation, spatial variabilit

Comparison of Generic and Proprietary Sodium Stibogluconate for the Treatment of Visceral Leishmaniasis in Kenya.

OBJECTIVE: To compare the use of generic and proprietary sodium stibogluconate for the treatment of visceral leishmaniasis (kala-azar). METHODS: A total of 102 patients with confirmed kala-azar were treated in a mission hospital in West Pokot region, Kenya, with sodium stibogluconate (20 mg/kg/day for 30 days)--either as Pentostam (PSM) or generic sodium stibogluconate (SSG); 51 patients were allocated alternately to each treatment group. FINDINGS: There were no significant differences in baseline demographic characteristics or disease severity, or in events during treatment. There were 3 deaths in the PSM group and 1 in the SSG group; 2 patients defaulted in each group. Only 1 out of 80 test-of-cure splenic aspirates was positive for Leishmania spp.; this patient was in the SSG group. Follow-up after > or = 6 months showed that 6 out of 58 patients had relapsed, 5 in the SSG group and 1 in the PSM group. No outcome variable was significantly different between the two groups. CONCLUSION: The availability of cheaper generic sodium stibogluconate, subject to rigid quality controls, now makes it possible for the health authorities in kala-azar endemic areas to provide treatment to many more patients in Africa

Low-Dose CT lung cancer screening:clinical evidence and implementation research

Lung cancer causes more deaths than breast, cervical, and colorectal cancer combined. Nevertheless, population-based lung cancer screening is still not considered standard practice in most countries worldwide. Early lung cancer detection leads to better survival outcomes: patients diagnosed with stage 1A lung cancer have a >75% 5-year survival rate, compared to < 5% at stage 4. LDCT thorax imaging for the secondary prevention of lung cancer has been studied at length, and has been shown to significantly reduce lung cancer mortality in high-risk populations. The US national lung screening trial reported 20% overall reduction in lung cancer mortality when comparing LDCT to chest x-ray, and the NELSON trial more recently reported 24% reduction when comparing LDCT to no screening. Hence, the focus has now shifted to implementation research. Consequently, the 4-IN-THE-LUNG-RUN consortium, based in 5 European countries, has set up a large-scale multi-center implementation trial. Successful implementation and accessibility of low-dose CT lung cancer screening are dependent on many factors, not limited to; population selection, recruitment strategy, CT-screening frequency, lung nodule management, participant compliance and cost-effectiveness. This review provides an overview of current evidence for LDCT lung cancer screening, and draws attention to major factors which need to be addressed to successfully implement standardized, effective, and accessible screening throughout Europe. Evidence shows that through the appropriate use of risk-prediction models and a more personalized approach to screening, efficacy could be improved. Further, extending the screening interval for low-risk individuals to reduce costs and associated harms is a possibility, and through the use of volumetric based measurement and follow-up, false positive results can be greatly reduced. Finally, smoking cessation programs could be a valuable addition to screening programs and artificial intelligence could offer the solution to the added workload pressures Radiologists are facing

Testable Design and Testing of High-Speed Superconductor Microelectronics

True software-defined radio cellular base stations require extremely fast data converters, which can not currently be implemented in semiconductor technology. Superconductor niobium-based delta ADCs have shown to be able to perform this task. The problem of testing these devices is a severe task, as very little is known about possible defects in this technology. This paper shows an approach for gaining information on these defects and illustrates how BIST can be a solution of detecting defects in ADCs under extreme conditions