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Nuclear deformation caused by external mechanical stimuli has been suggested to impact cellular activities, such as cell migration, gene expression, and proliferation; however, the underlying mechanisms remain largely unknown. Since cells reside in dynamic mechanical environments, investigation of viscoelastic behaviors of nuclei under mechanical conditions is believed to be key to understanding the mechanisms of the cellular responses to mechanical stimuli. In this study, we developed an in-situ observation system for the dynamic deformation behavior of the cell nucleus caused by mechanical substrate stretching. Human dermal fibroblasts cultured in a custom-made PDMS chamber were subjected to 5% strain by using a newly developed stretching system mounted on the stage of an inverted microscope. To obtain sequential "in-focus" fluorescent images of the nucleus during the cell stretching condition, the height of the stretching chamber was continuously controlled with a polynomial interpolation method during image acquisition. Intranuclear strains were then calculated from the fluorescence images obtained. As a result, compared to a lower strain rate condition, the whole nucleus strain in the direction of stretching tends to decrease during the application of stretching at a higher strain rate. In addition, the intranuclear strain showed heterogeneous magnitude distribution under the higher strain rate condition, while a uniform strain distribution was observed at the lower strain rate. The system we developed will help elucidate the role of the viscoelastic behavior of intranuclear structures in the cellular response to substrate stretching.

Many processes involve the manipulation of easily deformable objects such as food and cloth products, and the automation of such processes is required. However, there are still many challenges in pick-and-place, assembly and handling those objects using industrial robots. The insertion task involved in the formation of rubber hoses is an example of such a task. In this study, to automate the rubber hose insertion task, a preliminary investigation of friction force that affects the insertion task was examined and it was found that the air injection into the hose was effective to reduce the friction force. Based on the result, an air injection robotic hand (AIR-Hand) and a hose buckling preventing hand (HELP-Hand) were developed for a dual-arm robot. Furthermore, we integrated those two end effectors into one for a single-arm robot. The hose insertion task was successfully performed by both the dual-arm and single-arm robots, along with their corresponding manipulation plans.

There are currently many quadruped robots suited to a wide range of applications, but traversing some terrains, such as vertical ladders, remains an open challenge. There is still a need to develop adaptive robots that can walk and climb efficiently. This paper presents an adaptive quadruped robot that, by mimicking feline structure, supports several novel capabilities. We design a novel paw structure and several point-cloud-based sensory structures incorporating a quad-composite time-of-flight sensor and a dual-laser range finder. The proposed robot is equipped with physical and cognitive capabilities which include: 1) a dynamic-density topological map building with attention model, 2) affordance perception using the topological map, and 3) a neural-based locomotion model. The novel capabilities show strong integration between locomotion and internal–external sensory information, enabling short-term adaptations in response to environmental changes. The robot performed well in several situations: walking on natural terrain, walking with a leg malfunction, avoiding a sudden obstacle, climbing a vertical ladder. Further, we consider current problems and future development.