During photosynthesis, plants must control the utilization of light energy in order to avoid photoinhibition. We isolated an Arabidopsis mutant, pgr5 (proton gradient regulation), in which downregulation of photosystem II photochemistry in response to intense light was impaired. PGR5 encodes a novel thylakoid membrane protein that is involved in the transfer of electrons from ferredoxin to plastoquinone. This alternative electron transfer pathway, whose molecular identity has long been unclear, is known to function in vivo in cyclic electron flow around photosystem I. We propose that the PGR5 pathway contributes to the generation of a Delta(pH) that induces thermal dissipation when Calvin cycle activity is reduced. Under these conditions, the PGR5 pathway also functions to limit the overreduction of the acceptor side of photosystem I, thus preventing photosystem I photoinhibition.

Among the various synthetic gene carriers based on biomaterials, cationic polymers with polysaccharide backbones have long been studied as nonviral vectors due to their low immunogenicity and high water solubility. Schizophyllan, a beta-(1,3)-glucan, is one of the various polysaccharides that are clinically administered. Furthermore, its safety in the human body has already been confirmed. Various functional groups can be selectively introduced into the side chain, not into the main chain of schizophyllan. Therefore, we have synthesized various oligoamine conjugates from schizophyllan. It was confirmed that their in vitro transfection efficiencies are superior to that of polyethylenimine by adjusting the molecular weight and the degree of amination of cationic schizophyllan. While it was possible to reduce cytotoxicity by adjusting the amount of DNA complex per cell, as seen with poly-L-lysine, polyethylenimine, and chitosan, PEGylation was the most effective means of reducing toxicity. Furthermore, using cationic schizophyllan carriers, it was also possible to express a reporter protein for a long period of time due to a long residence time of plasmid DNA in cells.

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Autonomous robots are controlled using physical information acquired by various sensors. The sensors are susceptible to physical attacks, which tamper with the observed values and interfere with control of the autonomous robots. Recently, sensor spoofing attacks targeting subsequent algorithms which use sensor data have become large threats. In this paper, we introduce a new attack against the LiDAR-based simultaneous localization and mapping (SLAM) algorithm. The attack uses an adversarial LiDAR scan to fool a pose graph and a generated map. The adversary calculates a falsification amount for deceiving pose estimation and physically injects the spoofed distance against LiDAR. The falsification amount is calculated by gradient method against a cost function of the scan matching algorithm. The SLAM algorithm generates the wrong map from the deceived movement path estimated by scan matching. We evaluated our attack on two typical scan matching algorithms, iterative closest point (ICP) and normal distribution transform (NDT). Our experimental results show that SLAM can be fooled by tampering with the scan. Simple odometry sensor fusion is not a sufficient countermeasure. We argue that it is important to detect or prevent tampering with LiDAR scans and to notice inconsistencies in sensors caused by physical attacks.