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Waste cleanup efforts underway at the United States Department of Energy’s (DOE) Savannah River Site (SRS) in South Carolina, as well as other DOE nuclear sites, have created a need to characterize 79Se in radioactive waste inventories. Successful analysis of 79Se in high activity waste matrices is challenging for a variety of reasons. As a result of these unique challenges, the successful quantification of 79Se in the types of matrices present at SRS requires an extremely efficient and selective separation of 79Se from high levels of interfering radionuclides. A robust 79Se radiochemical separation method has been developed at the Savannah River National Laboratory (SRNL) which is routinely capable of successfully purifying 79Se from a wide range of interfering radioactive species. In addition to dramatic improvements in the Kd, ease, and reproducibility of the analysis, the laboratory time has been reduced from several days to only 6 h. [ABSTRACT FROM AUTHOR]

Waste cleanup efforts currently underway at the Savannah River Site have created a need to characterize99Tc in the various high activity waste matrices currently in Site inventories. The traditional method our laboratory used for analyzing99Tc in higher activity matrices was a solvent-solvent extraction method using Aliquat-336 in xylene. In an effort to eliminate the resulting generation of mixed wastes, a variety of different separation methodologies have been studied. Eichrom TEVA solid phase extractions using column technology have been employed in a case by case basis over the last several years. More recently, applications using Eichrom TEVA extraction discs and 3M Empore Tc extraction discs have also been explored. [ABSTRACT FROM AUTHOR]

Objective: Vaso-occlusive crisis (VOC) is a complex process that occurs in patients with sickle cell disease (SCD) and is often associated with pain and urgent hospitalization. A major instigator of VOC is microvascular obstruction by pathologically stiffened sickle red blood cells (RBCs), and thus, therapy relies heavily on optimizing intravenous fluid (IVF) hydration to increase RBC deformability. However, no evidence-based guidelines regarding the choice of IVF currently exist. We therefore analyzed alterations in biomechanical properties of sickle RBCs isolated from patients with homozygous SCD (hemoglobin SS) after exposure to different osmolarities of clinical IVF formulations., Methods: Atomic force microscopy (AFM) was used to assess stiffness of RBCs after exposure to different IVFs. A microfluidic model of the human capillary system was used to assess transit time (TT) and propensity to occlusion after exposure to the different IVF formulations., Results: Sickle RBCs exposed to normal saline (NS) had increased stiffness, TTs, and propensity to microchannel occlusion compared to other osmolarities., Conclusion: NS, an IVF formulation often used to treat patients with SCD during VOC, may induce localized microvascular obstruction due to alterations of sickle RBC biomechanical properties., (© 2017 John Wiley & Sons Ltd.)

The enrichment of viable cells is an essential step to obtain effective products for cell therapy. While procedures exist to characterize the viability of cells, most methods to exclude nonviable cells require the use of density gradient centrifugation or antibody-based cell sorting with molecular labels of cell viability. We report a label-free microfluidic technique to separate live and dead cells that exploits differences in cellular stiffness. The device uses a channel with repeated ridges that are diagonal with respect to the direction of cell flow. Stiff nonviable cells directed through the channel are compressed and translated orthogonally to the channel length, while soft live cells follow hydrodynamic flow. As a proof of concept, Jurkat cells are enriched to high purity of viable cells by a factor of 185-fold. Cell stiffness was validated as a sorting parameter as nonviable cells were substantially stiffer than live cells. To highlight the utility for hematopoietic stem cell transplantation, frozen samples of cord blood were thawed and the purity of viable nucleated cells was increased from 65% to over 94% with a recovery of 73% of the viable cells. Thus, the microfluidic stiffness sorting can simply and efficiently obtain highly pure populations of viable cells.