Gene Banks, Seed Libraries, and Vegetable Sanctuaries: The Cultivation and Conservation of Heritage Vegetables in Britain, 1970–1985

Individual seed saving and exchange are considered important components of contemporary efforts to conserve crop genetic diversity, which ramify at local, regional, and global scales. Yet the very fact that the contributions of these activities to conservation need to be made explicit by seed savers and those who study them indicates that the practices of seed saving and exchange may not immediately be recognized as conservation-oriented activities. This article investigates why and how individual seed saving came to be aligned with a broader conservation agenda in Britain through an historical examination of the promotion of seed saving by the Henry Doubleday Research Association (HDRA) in the 1970s and 1980s. It demonstrates how several HDRA initiatives that aimed to preserve vegetable diversity also re-inscribed British gardeners' ordinary labor as conservation work. This historical study complements sociological and ethnographic studies, highlighting the role of a prominent organization in creating pathways for individuals to engage in local, national, and international conservation through seed saving. It also serves as a reminder that the connections between these activities had to be made explicit—that is, that there was (and is) work involved in connecting individual acts of seed saving to conservation outcomes at different scales

Technical note: development of a 3D printed subresolution sandwich phantom for validation of brain SPECT analysis

Purpose: To make an adaptable, head shaped radionuclide phantom to simulate molecular imaging of the brain using clinical acquisition and reconstruction protocols. This will allow the characterization and correction of scanner characteristics, and improve the accuracy of clinical image analysis, including the application of databases of normal subjects. Methods: A fused deposition modeling 3D printer was used to create a head shaped phantom made up of transaxial slabs, derived from a simulated MRI dataset. The attenuation of the printed polylactide (PLA), measured by means of the Hounsfield unit on CT scanning, was set to match that of the brain by adjusting the proportion of plastic filament and air (fill ratio). Transmission measurements were made to verify the attenuation of the printed slabs. The radionuclide distribution within the phantom was created by adding 99mTc pertechnetate to the ink cartridge of a paper printer and printing images of gray and white matter anatomy, segmented from the same MRI data. The complete subresolution sandwich phantom was assembled from alternate 3D printed slabs and radioactive paper sheets, and then imaged on a dual headed gamma camera to simulate an HMPAO SPECT scan. Results: Reconstructions of phantom scans successfully used automated ellipse fitting to apply attenuation correction. This removed the variability inherent in manual application of attenuation correction and registration inherent in existing cylindrical phantom designs. The resulting images were assessed visually and by count profiles and found to be similar to those from an existing elliptical PMMA phantom. Conclusions: The authors have demonstrated the ability to create physically realistic HMPAO SPECT simulations using a novel head-shaped 3D printed subresolution sandwich method phantom. The phantom can be used to validate all neurological SPECT imaging applications. A simple modification of the phantom design to use thinner slabs would make it suitable for use in PET