18 Search Results

ABSTRACT Sickle cell disease is a destructive genetic disorder characterized by the formation of fibrils of deoxygenated hemoglobin, leading to the red blood cell (RBC) morphology changes that underlie the clinical manifestations of this disease. Using cryogenic soft X-ray tomography (SXT), we characterized the morphology of sickled RBCs in terms of volume and the number of protrusions per cell. We were able to identify statistically a relationship between the number of protrusions and the volume of the cell, which is known to correlate to the severity of sickling. This structural polymorphism allows for the classification of the stages of themore » sickling process. Recent studies have shown that elevated sphingosine kinase 1 (Sphk1)-mediated sphingosine 1-phosphate production contributes to sickling. Here, we further demonstrate that compound 5C, an inhibitor of Sphk1, has anti-sickling properties. Additionally, the variation in cellular morphology upon treatment suggests that this drug acts to delay the sickling process. SXT is an effective tool that can be used to identify the morphology of the sickling process and assess the effectiveness of potential therapeutics.« less

A two-step thermochemical reduction was developed to remove oxygen from commercial titanium dioxide, TiO₂, producing metallic titanium powder. The first step was to remove >95% of the oxygen by Mg reduction in a hydrogen atmosphere, followed by a de-oxygenation step. The goal is to produce Ti powder that meets the standard specifications for titanium. Several ancillary steps including granulation and heat treatment were introduced to modify the powder morphology, particle size and powder density to make the powder suitable for a range of applications. Detailed compositional analysis indicated that the final product meets the ASTM B299 for general-purpose titanium sponge.more » Lastly, the powder can be irregularly shaped or spherical with different granulation treatments.« less

We report a novel method was developed to produce spherical Ti-6Al-4V powder for advanced near-net-shape manufacturing processes including additive manufacturing and powder injection molding. The new process synergistically integrates a few common low-cost processing techniques including granulation, sintering, and de-oxygenation to produce spherical Ti alloy powders without relying on costly melting and atomizing techniques. This new granulation-sintering-deoxygenation (GSD) process can use low-cost source powders such as scrap Ti as the raw material. The spherical Ti-6Al-4V powder produced using this process has controlled particle size distribution and low oxygen content (< 0.15%), which meet the Aerospace Material Specification (AMS-4998) for sphericalmore » Ti-6Al-4V powder.« less