Three-dimensional reconstruction of a helical particle can be accomplished from a single lateral view, but in practice the reconstruction procedure must be optimized to make the best use of the available projection data. This is especially true for unstained frozen hydrated (ice embedded) specimens, whose micrographs have a characteristically low signal to noise ratio. Deoxy-sickle hemoglobin (HbS) fibers present an additional difficulty as well because these particles have a variable pitch and may also have variation in their unit cell structure. We have carried out a three-dimensional reconstruction of an unstained frozen hydrated HbS fiber (Figs. 1 & 2) by convolution back projection. The procedures used to facilitate this three-dimensional reconstruction are described below.In this work especially close attention was paid to determining the image magnification in order that the reconstruction of this HbS fiber could be compared with previous HbS fiber models (Table 1) which are based on reconstructions of negatively stained HbS fibers. In order to determine the HbS fiber's dimensions accurately the particle (Fig. 1a) was reconstructed twice.
Three-dimensional reconstruction of fibrin clot networks from stereoscopic intermediate voltage electron microscope images and analysis of branching