Processing of Cryo-EM Movie Data.

Direct detector device (DDD) cameras dramatically enhance the capabilities of electron cryomicroscopy (cryo-EM) due to their improved detective quantum efficiency (DQE) relative to other detectors. DDDs use semiconductor technology that allows micrographs to be recorded as movies rather than integrated individual exposures. Movies from DDDs improve cryo-EM in another, more surprising, way. DDD movies revealed beam-induced specimen movement as a major source of image degradation and provide a way to partially correct the problem by aligning frames or regions of frames to account for this specimen movement. In this chapter, we use a self-consistent mathematical notation to explain, compare, and contrast several of the most popular existing algorithms for computationally correcting specimen movement in DDD movies. We conclude by discussing future developments in algorithms for processing DDD movies that would extend the capabilities of cryo-EM even further.

INDUCED SEISMICITY. High-rate injection is associated with the increase in U.S. mid-continent seismicity.

An unprecedented increase in earthquakes in the U.S. mid-continent began in 2009. Many of these earthquakes have been documented as induced by wastewater injection. We examine the relationship between wastewater injection and U.S. mid-continent seismicity using a newly assembled injection well database for the central and eastern United States. We find that the entire increase in earthquake rate is associated with fluid injection wells. High-rate injection wells (>300,000 barrels per month) are much more likely to be associated with earthquakes than lower-rate wells. At the scale of our study, a well's cumulative injected volume, monthly wellhead pressure, depth, and proximity to crystalline basement do not strongly correlate with earthquake association. Managing injection rates may be a useful tool to minimize the likelihood of induced earthquakes.

Leukoencephalopathy following combined therapy of central nervous system leukemia and lymphoma.

We report a from of disseminated necrotizing leukoencephalopathy observed in five children with acute lymphoblastic leukemia or lymphoma, who received systemic chemotherapy, brain radiation, and intrathecal (IT) methotrexate, cytosine arabinoside and hydrocortisone because of meningeal tumor involvement. Three children developed a progressive neurologic disease at the end of IT therapy or shortly thereafter. The lesions consisted in discrete, apparently coalescent foci of coagulative necrosis in the white matter, with a remarkable absence of inflammatory cells, little or no tissue break-down, and striking axonal swellings. The adjacent tissue showed status spongiosus and moderate astrocytic hypertrophy. Vascular lesions were few and inconstant.