Evolutionary adaptation of visual pigments in geckos for their photic environment

家の守り神「ヤモリ」が夜でも色を見分けられるのはなぜ --ヤモリが持つ特殊な色覚能力の分子メカニズムを解明--. 京都大学プレスリリース. 2021-10-04.Vertebrates generally have a single type of rod for scotopic vision and multiple types of cones for photopic vision. Noteworthily, nocturnal geckos transmuted ancestral photoreceptor cells into rods containing not rhodopsin but cone pigments, and, subsequently, diurnal geckos retransmuted these rods into cones containing cone pigments. High sensitivity of scotopic vision is underlain by the rod’s low background noise, which originated from a much lower spontaneous activation rate of rhodopsin than of cone pigments. Here, we revealed that nocturnal gecko cone pigments decreased their spontaneous activation rates to mimic rhodopsin, whereas diurnal gecko cone pigments recovered high rates similar to those of typical cone pigments. We also identified amino acid residues responsible for the alterations of the spontaneous activation rates. Therefore, we concluded that the switch between diurnality and nocturnality in geckos required not only morphological transmutation of photoreceptors but also adjustment of the spontaneous activation rates of visual pigments

Pinopsin evolved as the ancestral dim-light visual opsin in vertebrates

脊椎動物の視覚進化モデルを修正 --暗所視と色覚はどっちが先か--. 京都大学プレスリリース. 2018-10-02.Pinopsin is the opsin most closely related to vertebrate visual pigments on the phylogenetic tree. This opsin has been discovered among many vertebrates, except mammals and teleosts, and was thought to exclusively function in their brain for extraocular photoreception. Here, we show the possibility that pinopsin also contributes to scotopic vision in some vertebrate species. Pinopsin is distributed in the retina of non-teleost fishes and frogs, especially in their rod photoreceptor cells, in addition to their brain. Moreover, the retinal chromophore of pinopsin exhibits a thermal isomerization rate considerably lower than those of cone visual pigments, but comparable to that of rhodopsin. Therefore, pinopsin can function as a rhodopsin-like visual pigment in the retinas of these lower vertebrates. Since pinopsin diversified before the branching of rhodopsin on the phylogenetic tree, two-step adaptation to scotopic vision would have occurred through the independent acquisition of pinopsin and rhodopsin by the vertebrate lineage

筋骨格構造のメカニズムに基づく運動生成法の構築

本研究の目的は, 人間の身体構造である筋骨格構造のメカニズムを解析し，筋骨格構造特有のメカニズムと巧みな運動の関係性を明らかにすることである．本研究では，筋内力フィードフォワード制御法における任意ベクトルを利用した手先軌道の整形法を提案し，その有効性をシミュレーション結果より示した．また，プーリモデルと非プーリモデルの特徴を併せ持つ関節構造を提案した．さらに，リンクの物理パラメータを変更可能な受動歩行ロボットを提案した．The purpose of this study is to deepen the understanding of the relationship between the mechanism of the musculoskeletal structure and skillful movements by analyzing this mechanism. Herein, an end-point trajectory shaping method using arbitrary vector for a muscular internal force feedforward controller is proposed and its effectiveness is confirmed through simulation. urthermore, a new joint structure is proposed wherein the moment arms are changed according to a joint angle and its effectiveness is confirmed by experiment. Also, a passive walking robot with changeable physical parameters of links is proposed.研究分野：ロボット工

Motion Producing Method based on the Mechanism of Musculoskeletal Structure

本研究の目的は, 人間の身体構造である筋骨格構造のメカニズムを解析し，筋骨格構造特有のメカニズムと巧みな運動の関係性を明らかにすることである．本研究では，筋内力フィードフォワード制御法における任意ベクトルを利用した手先軌道の整形法を提案し，その有効性をシミュレーション結果より示した．また，プーリモデルと非プーリモデルの特徴を併せ持つ関節構造を提案した．さらに，リンクの物理パラメータを変更可能な受動歩行ロボットを提案した．The purpose of this study is to deepen the understanding of the relationship between the mechanism of the musculoskeletal structure and skillful movements by analyzing this mechanism. Herein, an end-point trajectory shaping method using arbitrary vector for a muscular internal force feedforward controller is proposed and its effectiveness is confirmed through simulation. urthermore, a new joint structure is proposed wherein the moment arms are changed according to a joint angle and its effectiveness is confirmed by experiment. Also, a passive walking robot with changeable physical parameters of links is proposed.研究分野：ロボット工

Numerical analysis of feedforward position control for non-pulley musculoskeletal system : a case study of muscular arrangements of a two-link planar system with six muscles

The height of semiconductor heterojunction band offsets (band discontinuities) determines the feasability and performance of important electronic devices. In consequence of the progress made in epitaxial techniques, strained pseudomorphic layers are today routine parts of such devices. In the present thesis the question is investigated how the band line-up at a III-V heterojunction is affected when one or both constituents are strained. We have used in situ photoelectron spectroscopy to study the strain dependence of the band offsets at pseudomorphic InAs/GaAs, InAs/AIAs and GaAs/lnP heterojunctions. Heterostructure samples have been prepared by standard molecular beam epitaxy (MBE) or metal organic molecular beam epitaxy (MOMBE). The lattice mismatch amounts up to 7 percent. We emphasize the modifications of the classical core-level method due to the strain. In a short theoretical part we have generalized the most important model theory on band offsets, the interface dipole theory due to Tersoff, to the case of strain. Further chapters treat the influence of doping on the photoemission measurement of band offsets and the Schottky barrier height at clean Au/lnAs contacts