COVER In Germany, a changing climate has led to bark beetle outbreaks that have ravaged Norway spruce forests, such as this one in the Bavarian Forest National Park. The damage has helped fuel a fierce debate over the future of forest management. See page 1184.

Photo: Ingo Arndt/Minden Pictures

ONLINE COVER An ultrathin rechargeable zinc ion fiber battery integrates into textiles, allowing for personalized health monitoring. Cost-effective, eco-friendly zinc ion batteries appear a frontrunner for powering wearable electronics, but poor mechanical properties and low ion transport of current gel electrolytes limit the use of zinc ion batteries in wearable devices. The battery designed by Xiao et al. uses graphene oxide hydrogel electrolytes to overcome these issues. The approach provides a scalable, stable power solution for continuous heart rate, body temperature, humidity, and altitude monitoring.

ONLINE COVER Inflammatory SINEs. This month's cover features a retinal color photograph showing age-related macular degeneration in a 75-year-old man. In the center of the retina, damage to the retinal pigment epithelium (RPE) has caused enhanced visibility of the underlying choroidal blood vessels and impaired vision. Wang et al. identified DDX17, an RNA helicase, as a sensor of elevated levels of RNA transcripts from short interspersed nuclear elements (SINEs). DDX17 can initiate a noncanonical form of NLRC4-mediated inflammasome activation leading to RPE degeneration in the eye.

ONLINE COVER Takeoff and Landings. The ability for aerial robots to take off and land on a variety of irregular surfaces will broaden the range of environments where these robots could be deployed. Influenced by how birds take off, land, and grasp, Roderick et al. have developed a bird-inspired grasping system called Stereotyped Nature-inspired Aerial Grasper (SNAG). The researchers integrated SNAG into a quadcopter to demonstrate perching on tree branches of different sizes, orientations, and surface conditions. This month's cover is a photograph of SNAG on a quadcopter perched on a branch.

ONLINE COVER This week, Lo et al. characterize the signaling profiles mediated by the normal and mutant forms of the GTPase RIT1 in lung epithelial cells and show that either form can promote tumor development. The image shows a scanning electron microscopy image of lung adenocarcinoma cells growing among alveoli.

ONLINE COVER Human-Specific Interaction. This immunofluorescence image shows a human oligodendrocyte stained for myelin basic protein (green), oligodendrocyte transcription factor 2 (red) and DAPI (blue) after treatment with anti-CD22 antibody. Studying the lysosomal storage disorder Niemann-Pick type C disease, Pluvinage et al. demonstrated that CD22, expressed in human but not mouse oligodendrocytes, is increased in the brain of patients and plays a critical role in lysosome dysfunction in patient-derived cells by interacting with insulin-like growth factor 2 receptor (IGF2R). Inhibiting this interaction reduced lysosome abnormalities in patient-derived cells, suggesting that blocking CD22-IGF2R binding might have therapeutic effects in Niemann-Pick type C disease.