Electron micrographs of synapses in frogs

This dataset contains transmission electron micrographs of synapses of a frog.
It has been published in [1] and has been re-used to evaluate automated synaptic vesicle segmentation in [2].
To obtain the data, frog (Rana pipiens) cutaneous pectoris muscles were dissected and mounted in sylgard-lined chambers, in a frog Ringer buffer (115 mM NaCl, 2 mM KCl, 1.8 mM CaCl2, 2.4 mM NaHCO3, pH 7.2). Samples were fixed with 2% glutaraldehyde in frog Ringer, at -2°C for 40-60 minutes, followed by washing, post-fixing with 2% OsO4 in PBS, dehydration through a series of ethanol solutions and propylene oxide, and embedding in Epon resin. A proportion of the vesicles was labeled with precipitated di-amino-benzidine, using a photo-oxidation procedure. The blocks were then sectioned (80-90 nm thickness), and were post-stained with 2% uranyl acetate in a 1:1 ethanol-water mixture (1 minute incubation). Images were acquired using a CM-10 Philips electron microscope, using film negatives. These were enlarged 2.69-fold by transferring to photographic paper (Eastman Kodak Company, Rochester, NY). The paper was scanned at 300 dpi, to obtain the final images.
The data is or organized into two different subfolders "train_unlabeled" and "test" that were used for unsupervised domain adaptation and qualitative evaluation respectively.
Each folder contains hdf5 files with stacks of electron micrograph, with the image data stored in the internal dataset "raw".

References:
[1] Rizzoli and Betz, The Structural Organization of the Readily Releasable Pool of Synaptic Vesicles, Science 2004, DOI: 10.1126/science.1094682
[2] Muth, Moschref et al., 2024, Preprint to be published