We describe a novel UV-curable mold that is stiff enough for replicating dense sub-100-nm features even with a high aspect ratio. It also allows for flexibility when the mold is prepared on a flexible support such that large area replication can be accomplished. The composite material of the mold is inert to chemicals and solvents. The surface energy is made low with a small amount of releasing agent such that the mold can be removed easily and cleanly after patterning. In addition, the material allows self-replication of the mold. These unique features of the mold material should make the mold quite useful for various patterning purposes.

The N-terminal transit peptides of nuclear-encoded plastid proteins are necessary and sufficient for their import into plastids, but the information encoded by these transit peptides remains elusive, as they have a high sequence diversity and lack consensus sequences or common sequence motifs. Here, we investigated the sequence information contained in transit peptides. Hierarchical clustering on transit peptides of 208 plastid proteins showed that the transit peptide sequences are grouped to multiple sequence subgroups. We selected representative proteins from seven of these multiple subgroups and confirmed that their transit peptide sequences are highly dissimilar. Protein import experiments revealed that each protein contained transit peptide-specific sequence motifs critical for protein import into chloroplasts. Bioinformatics analysis identified sequence motifs that were conserved among members of the identified subgroups. The sequence motifs identified by the two independent approaches were nearly identical or significantly overlapped. Furthermore, the accuracy of predicting a chloroplast protein was greatly increased by grouping the transit peptides into multiple sequence subgroups. Based on these data, we propose that the transit peptides are composed of multiple sequence subgroups that contain distinctive sequence motifs for chloroplast targeting.

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Since the introduction of ultraviolet (UV)-curable polyurethane acrylate (PUA) materials in 2004, our group has extensively used the material in various applications ranging from nanopatterning, biomimetics, microfluidics, to tissue engineering. In this highlight, we aim to provide a brief overview of the properties and applications of PUA with particular focus on the ability of tuning modulus (20-320 MPa) and surface energy (20-60 mJ m À2 ). These unique features enable us to use the material in various patterning applications as a mold and a patterned film, respectively. In addition, one can benefit from several other features of PUA such as self-replication, partial curing, flexibility, biocompatibility, and transparency. These issues are also briefly described along with their applications.

The demand for face masks is increasing exponentially due to the coronavirus pandemic and issues associated with airborne particulate matter (PM). However, both conventional electrostatic‐ and nanosieve‐based mask filters are single‐use and are not degradable or recyclable, which creates serious waste problems. In addition, the former loses function under humid conditions, while the latter operates with a significant air‐pressure drop and suffers from relatively fast pore blockage. Herein, a biodegradable, moisture‐resistant, highly breathable, and high‐performance fibrous mask filter is developed. Briefly, two biodegradable microfiber and nanofiber mats are integrated into a Janus membrane filter and then coated by cationically charged chitosan nanowhiskers. This filter is as efficient as the commercial N95 filter and removes 98.3% of 2.5 µm PM. The nanofiber physically sieves fine PM and the microfiber provides a low pressure differential of 59 Pa, which is comfortable for human breathing. In contrast to the dramatic performance decline of the commercial N95 filter when exposed to moisture, this filter exhibits negligible performance loss and is therefore multi‐usable because the permanent dipoles of the chitosan adsorb ultrafine PM (e.g., nitrogen and sulfur oxides). Importantly, this filter completely decomposes within 4 weeks in composting soil.