In-Plane Deformation Mechanics for Highly Stretchable Electronics.

Scissoring in thick bars suppresses buckling behavior in serpentine traces that have thicknesses greater than their widths, as detailed in a systematic set of analytical and experimental studies. Scissoring in thick copper traces enables elastic stretchability as large as ≈350%, corresponding to a sixfold improvement over previously reported values for thin geometries (≈60%).

Markerless chromosomal gene deletion in Clostridium beijerinckii using CRISPR/Cas9 system.

The anaerobic spore-forming, gram-positive, solventogenic clostridia are notorious for being difficult to genetically engineer. Based on CRISPR/Cas9 assisted homologous recombination, we demonstrated that clean markerless gene deletion from the chromosome can be easily achieved with a high efficiency through a single-step transformation in Clostridium beijerinckii NCIMB 8052, one of the most prominent strains for acetone, butanol and ethanol (ABE) production. This highly efficient genome engineering system can be further explored for multiplex genome engineering purposes. The protocols and principles developed in this study provided valuable references for genome engineering in other microorganisms lacking developed genetic engineering tools.

Digital cameras with designs inspired by the arthropod eye.

In arthropods, evolution has created a remarkably sophisticated class of imaging systems, with a wide-angle field of view, low aberrations, high acuity to motion and an infinite depth of field. A challenge in building digital cameras with the hemispherical, compound apposition layouts of arthropod eyes is that essential design requirements cannot be met with existing planar sensor technologies or conventional optics. Here we present materials, mechanics and integration schemes that afford scalable pathways to working, arthropod-inspired cameras with nearly full hemispherical shapes (about 160 degrees). Their surfaces are densely populated by imaging elements (artificial ommatidia), which are comparable in number (180) to those of the eyes of fire ants (Solenopsis fugax) and bark beetles (Hylastes nigrinus). The devices combine elastomeric compound optical elements with deformable arrays of thin silicon photodetectors into integrated sheets that can be elastically transformed from the planar geometries in which they are fabricated to hemispherical shapes for integration into apposition cameras. Our imaging results and quantitative ray-tracing-based simulations illustrate key features of operation. These general strategies seem to be applicable to other compound eye devices, such as those inspired by moths and lacewings (refracting superposition eyes), lobster and shrimp (reflecting superposition eyes), and houseflies (neural superposition eyes).