Self-localization based on Image Features of Omni-directional Image

Omni-vision system using an omni-mirror is popular to acquire environment information around an autonomous mobile robot. In RoboCup soccer middle size robot league in particular, self-localization methods based on white line extraction on the soccer field are popular. We have studied a self-localization method based on image features, for example, SIFT and SURF, so far. Comparative studies with a conventional self-localization method based on white line extraction are conducted. Compared to the self-localization method based on white line extraction, the method based on image feature can be applied to a general environment with a compact database

Geometric trade-off between contractile force and viscous drag determines the actomyosin-based motility of a cell-sized droplet

動きまわる人工細胞、その鍵は摩擦にあり --細胞が狭い空間を利用して運動する仕組みを解明--. 京都大学プレスリリース. 2022-07-21.Cell migration in confined environments is fundamental for diverse biological processes from cancer invasion to leukocyte trafficking. The cell body is propelled by the contractile force of actomyosin networks transmitted from the cell membrane to the external substrates. However, physical determinants of actomyosin-based migration capacity in confined environments are not fully understood. Here, we develop an in vitro migratory cell model, where cytoplasmic actomyosin networks are encapsulated into droplets surrounded by a lipid monolayer membrane. We find that the droplet can move when the actomyosin networks are bound to the membrane, in which the physical interaction between the contracting actomyosin networks and the membrane generates a propulsive force. The droplet moves faster when it has a larger contact area with the substrates, while narrower confinement reduces the migration speed. By combining experimental observations and active gel theory, we propose a mechanism where the balance between sliding friction force, which is a reaction force of the contractile force, and viscous drag determines the migration speed, providing a physical basis of actomyosin-based motility in confined environments

Examining the assembly pathways and active microtubule mechanics underlying spindle self-organization

The bipolar organization of the microtubule-based mitotic spindle is essential for the faithful segregation of chromosomes in cell division. Despite our extensive knowledge of genes and proteins, the physical mechanism of how the ensemble of microtubules can assemble into a proper bipolar shape remains elusive. Here, we study the pathways of spindle self-organization using cell-free Xenopus egg extracts and computer-based automated shape analysis. Our microscopy assay allows us to simultaneously record the growth of hundreds of spindles in the bulk cytoplasm and systematically analyze the shape of each structure over the course of self-organization. We find that spindles that are maturing into a bipolar shape take a route that is distinct from those ending up with faulty structures, such as those of a tripolar shape. Moreover, matured structures are highly stable with little occasions of transformation between different shape phenotypes. Visualizing the movement of microtubules further reveals a fraction of microtubules that assemble between extra poles and push the poles apart, suggesting the presence of active extensile force that prevents pole coalescence. Together, we propose that a proper control over the magnitude and location of the extensile, pole-pushing force is crucial for establishing spindle bipolarity while preventing multipolarity.Comment: 22 pages, 5 + 2 figure

Plant complex type free N-glycans occur in tomato xylem sap

Free N-glycans (FNGs) are ubiquitous in growing plants. Further, acidic peptide:N-glycanase is believed to be involved in the production of plant complex-type FNGs (PCT-FNGs) during the degradation of dysfunctional glycoproteins. However, the distribution of PCT-FNGs in growing plants has not been analyzed. Here, we report the occurrence of PCT-FNGs in the xylem sap of the stem of the tomato plant

Regulated growth of diatom cells on self-assembled monolayers

We succeeded in regulating the growth of diatom cells on chemically modified glass surfaces. Glass surfaces were functionalized with -CF(3), -CH(3), -COOH, and -NH(2 )groups using the technique of self-assembled monolayers (SAM), and diatom cells were subsequently cultured on these surfaces. When the samples were rinsed after the adhesion of the diatom cells on the modified surfaces, the diatoms formed two dimensional arrays; this was not possible without the rinsing treatment. Furthermore, we examined the number of cells that grew and their motility by time-lapse imaging in order to clarify the interaction between the cells and SAMs. We hope that our results will be a basis for developing biodevices using living photosynthetic diatom cells

Development of MONSAKUN Touch and Practical Use in Class: Realization of Lesson of Posing of Arithmetical Word Problems

和若しくは差で解ける算数文章問題を対象とした単文統合型の作問学習支援システム“モンサクン”は数年に渡り複数の小学校の授業で利用されている．しかしながら，これらの授業では既に対象領域の学習を終えている2年生以上を対象としていたため，付加的な学習としての位置づけになっていた．本研究では，対象領域を学習中である1年生を対象に，単文統合型の作問の実施を目指した．このためにはシステムと授業の融合が必要となるため，(1) システムの通常教室での利用，(2) 作問状況のリアルタイムでの把握，(3) 作問法の教授，が解決すべき課題となった．本論文ではこれらの課題を解決するために行った，(I) モンサクンのタブレット化，(II) 作問状況モニタリングと集計・可視化機能の実現，(III) 作問法の教授法の考案，を述べる．またシステムを用いた9時限に渡る実践を行い，その分析結果から，システムが十分に利用可能であったこと，学習者の問題解決能力や作問能力の向上が見られたことが確認できたので，これを報告する

Interactive Learning Environment for Posing 1-step Multiplication Word Problem and Its Experimental Use

筆者らはこれまでに，1 回の加減で解決できる算数文章題を対象として，三文構成モデルによる作問学習支援システムを開発している．本研究では，システムを小学校2年生で学習する乗算の領域へと拡張するものであり，システムの拡張から1クラス9時限の実践利用までを行ったので，報告する．結果としては，システムを利用することで問題解決能力はあっても，構造の理解が浅い学習者に対して，構造理解を深められることを示唆する結果が得られた