COVER False-color micrograph of pure titanium with a nanotwinned structure, where each color represents a region with an identical crystallographic orientation. The nanotwinned structure was produced via a multistep cryoforging process carried out in liquid nitrogen, followed by annealing at 400°C. As a result, the processed material exhibits ultrahigh strength and ductility, especially at cryogenic temperatures. See page 1363.

ONLINE COVER A scanning laser beam "prints" a metal component from on a bed of metallic powder. Over the last few decades metal additive manufacturing has gained traction but controlling heating and other laser-material interactions has proved challenging. To address these issues, researchers have used different laser beam shaping strategies. Tumkur et al. demonstrate that Bessel beams, a broad class of nondiffractive beam shapes, can produce denser and nearly defect-free structures over a wider parameter space, improving metal additive manufacturing.

ONLINE COVER Critical Crossroads. This month's cover features an immunofluorescence image of a murine tumor-draining lymph node containing metastatic melanoma cells (GFP-expressing YUMM1.7 cells; cyan). Tumor cells reach the tumor-draining lymph node via afferent lymphatic vessels that intersect with the subcapsular and interfollicular sinuses (sinus-lining lymphatic endothelial cells stained with anti-LYVE-1; orange). The sinuses run around and between B cell follicles (B cells stained with anti-B220; purple). A Review by du Bois, Heim, and Lund summarizes our current understanding of the structural biology of tumor-draining lymph nodes, how they are primed to receive metastasizing tumor cells, and their unique impact on prognosis and immunotherapy.

ONLINE COVER Special Issue on Human-Robot Interaction. Prosthetic systems that provide a strong sense of agency and ownership between the user and the prosthesis will improve performance and reduce the rate of device abandonment. Marasco et al. have developed a neural-machine interface for a bionic prosthetic arm that leverages the sense of touch to enhance physical ownership and provides grip kinesthesia to enhance agency. This month's cover is a photograph of the inside socket of a bionic prosthetic arm (see also Focus by Ortiz-Catalan).

ONLINE COVER This week, Wei et al. show that a two-component signaling system in a plant pathogen promotes pilus extension and virulence by degrading the second messenger c-di-GMP. The image is an electron micrograph of a Xanthomonas oryzae pv. oryzicola cell showing the single, long flagellum and several pili at one pole.

ONLINE COVER Advancing Adoptive Cell Therapy. This image shows epithelial cell adhesion molecule (EpCAM, green) in the cytoplasm of a cytotoxic T cell. The nucleus is shown in blue. A challenge in adoptive T cell therapy for cancer is avoiding exhaustion and death of T cells after transfer. To address this, Zhang et al. screened a library of microRNAs (miRs) to identify those that promoted T cell function. The authors showed that ectopic expression of miR-200c markedly enhanced longevity and antitumor function of transferred T cells, and the effect of miR-200c was driven by up-regulation of EpCAM. These findings suggest that the miR-200c—EpCAM axis may be targeted to improve adoptive T cell therapies.