13 research outputs found
Temperature-ramped 129Xe spin-exchange optical pumping
We describe temperature-ramped spin-exchange optical pumping (TR-SEOP) in an automated high-throughput batch-mode 129Xe hyperpolarizer utilizing three key temperature regimes: (i) âhotâwhere the 129Xe hyperpolarization rate is maximal, (ii) âwarmâ-where the 129Xe hyperpolarization approaches unity, and (iii) âcoolâ where hyperpolarized 129Xe gas is transferred into a Tedlar bag with low Rb content (<5 ng per âŒ1 L dose) suitable for human imaging applications. Unlike with the conventional approach of batch-mode SEOP, here all three temperature regimes may be operated under continuous high-power (170 W) laser irradiation, and hyperpolarized 129Xe gas is delivered without the need for a cryocollection step. The variable-temperature approach increased the SEOP rate by more than 2-fold compared to the constant-temperature polarization rate (e.g., giving effective values for the exponential buildup constant ÎłSEOP of 62.5 ± 3.7 Ă 10â3 minâ1 vs 29.9 ± 1.2 Ă 10â3 minâ1) while achieving nearly the same maximum %PXe value (88.0 ± 0.8% vs 90.1% ± 0.8%, for a 500 Torr (67 kPa) Xe cell loadingcorresponding to nuclear magnetic resonance/magnetic resonance imaging (NMR/MRI) enhancements of âŒ3.1 Ă 105 and âŒ2.32 Ă 108 at the relevant fields for clinical imaging and HP 129Xe production of 3 T and 4 mT, respectively); moreover, the intercycle âdeadâ time was also significantly decreased. The higher-throughput TR-SEOP approach can be implemented without sacrificing the level of 129Xe hyperpolarization
or the experimental stability for automation-making this approach beneficial for improving the overall 129Xe production rate in clinical settings
Improving knowledge discovery from synthetic aperture radar images using the linked open data cloud and Sextant
In the last few years, thanks to projects like TELEIOS, the linked open data cloud has been rapidly populated with geospatial data some of it describing Earth Observation products (e.g., CORINE Land Cover, Urban Atlas). The abundance of this data can prove very useful to the new missions (e.g., Sentinels) as a means to increase the usability of the millions of images and EO products that are expected to be produced by these missions. In this paper, we explain the relevant opportunities by demonstrating how the process of knowledge discovery from TerraSAR-X images can be improved using linked open data and Sextant, a tool for browsing and exploration of linked geospatial data, as well as the creation of thematic maps
Managing big, linked, and open earth-observation data: Using the TELEIOS/LEO software stack
Big Earth-observation (EO) data that are made freely available by space agencies come from various archives. Therefore, users trying to develop an application need to search within these archives, discover the needed data, and integrate them into their application. In this article, we argue that if EO data are published using the linked data paradigm, then the data discovery, data integration, and development of applications becomes easier. We present the life cycle of big, linked, and open EO data and show how to support their various stages using the software stack developed by the European Union (EU) research projects TELEIOS and the Linked Open EO Data for Precision Farming (LEO). We also show how this stack of tools can be used to implement an operational wildfire-monitoring service
Real-Time Wildfire Monitoring Using Scientific Database and Linked Data Technologies
We present a real-time wildfire monitoring service that exploits satellite images and linked geospatial data to detect hotspots and monitor the evolution of fire fronts. The service makes heavy use of scientific database technologies (array databases, SciQL, data vaults) and linked data technologies (ontologies, linked geospatial data, stSPARQL) and is implemented on top of MonetDB and Strabon. The service is now operational at the National Observatory of Athens and has been used during the previous summer by emergency managers monitoring wildfires in Greece
Serum Soluble TACI, a BLyS Receptor, Is a Powerful Prognostic Marker of Outcome in Chronic Lymphocytic Leukemia
BLyS is involved in CLL biology and its low soluble serum levels related to a shorter time to first treatment (TFT). TACI is a BLyS receptor and can be shed from cells' surface and circulate in soluble form (sTACI). We investigated the impact of serum BLyS and sTACI levels at diagnosis in CLL patients and their relationship with disease parameters and patients' outcome. Serum BLyS was determined in 73 patients, while sTACI in 60. Frozen sera drawn at diagnosis were tested by ELISA. sTACI concentrations correlated with BLyS ( = â0.000021), b2-microglobulin ( = 0.005), anemia ( = â0.03), thrombocytopenia ( = 0.04), Binet stage ( = 0.02), and free light chains ratio ( = 0.0003). Soluble BLyS levels below median and sTACI values above median were related to shorter TFT ( = 0.0003 and 0.007). During a ten-year followup, sTACI levels, but not BLyS, correlated with survival ( = 0.048). In conclusion, we confirmed the prognostic significance of soluble BLyS levels with regard to TFT in CLL patients, and, more importantly, we showed for the first time that sTACI is a powerful prognostic marker, related to parameters of disease activity and staging and, more importantly, to TFT and OS
Serum Soluble TACI, a BLyS Receptor, Is a Powerful Prognostic Marker of Outcome in Chronic Lymphocytic Leukemia
BLyS is involved in CLL biology and its low soluble serum levels related to a shorter time to first treatment (TFT). TACI is a BLyS receptor and can be shed from cellsâ surface and circulate in soluble form (sTACI). We investigated the impact of serum BLyS and sTACI levels at diagnosis in CLL patients and their relationship with disease parameters and patientsâ outcome. Serum BLyS was determined in 73 patients, while sTACI in 60. Frozen sera drawn at diagnosis were tested by ELISA. sTACI concentrations correlated with BLyS (P=-0.000021), b2-microglobulin (P=0.005), anemia (P=-0.03), thrombocytopenia (P=0.04), Binet stage (P=0.02), and free light chains ratio (P=0.0003). Soluble BLyS levels below median and sTACI values above median were related to shorter TFT (P=0.0003 and 0.007). During a ten-year followup, sTACI levels, but not BLyS, correlated with survival (P=0.048). In conclusion, we confirmed the prognostic significance of soluble BLyS levels with regard to TFT in CLL patients, and, more importantly, we showed for the first time that sTACI is a powerful prognostic marker, related to parameters of disease activity and staging and, more importantly, to TFT and OS
NMR hyperpolarization techniques of gases
Nuclear spin polarization can be significantly increased through the process of hyperpolarization, leading to an increase in the sensitivity of nuclear magnetic resonance (NMR) experiments by 4â8 orders of magnitude. Hyperpolarized gases, unlike liquids and solids, can often be readily separated and purified from the compounds used to mediate the hyperpolarization processes. These pure hyperpolarized gases enabled many novel MRI applications including the visualization of void spaces, imaging of lung function, and remote detection. Additionally, hyperpolarized gases can be dissolved in liquids and can be used as sensitive molecular probes and reporters. This Minireview covers the fundamentals of the preparation of hyperpolarized gases and focuses on selected applications of interest to biomedicine and materials science