Combat Losses of Nuclear-Powered Warships: Contamination, Collateral Damage and the Law

There have been non-combat losses of nuclear-powered warships during sea trials and peacetime patrol missions. Nuclear contamination is spreading from some of these sinking sites. It is also conceivable that combat losses of nuclear-powered warships could cause contamination of civilians, civilian objects and the natural environment. If such combat losses occur at sea, both belligerent and neutral States will have to deal with a difficult question: to what extent and by who can harm resulting from such contamination be compensated for payment of damages. This article examines legal issues stemming from prospective combat losses of nuclear-powered warships from the perspectives of the laws of armed conflict and neutrality at sea. More specifically, it attempts to dissect whether nuclear contamination incidentally caused to civilians, civilian objects and the natural environment during international armed conflict can be properly categorized as collateral damage as envisaged by the laws of armed conflict and neutrality at sea, the lawfulness of which is assessed following the principle of proportionality

How to Conduct Lawfare against Nuclear Weapons More Effectively in Japan : A View from the Law of Armed Conflict

For more than 75 years, anti-nuclear-weapons movements in Japan have been asserting the illegality of the use of nuclear weapons. These assertions, however, can sometimes be described as generalist or even stereotypical. In fact, they rely mainly on the principle of humanity which could be interpreted in many ways. For this reason, legal experts among the Japanese Government have refuted them relatively easily. Nonetheless, there are other technical but equally important issues that could serve as a basis for more convincing legal arguments. Using the law of armed conflict as an analytical lens, this paper examines these issues, such as the applicability of the Additional Protocol I to the Geneva Conventions and the Statute of the International Criminal Court to the use of nuclear weapons, and the legal validity of nuclear belligerent reprisals. By analyzing these legal considerations, this paper explores more effective ways for conducting legal warfare against the use of nuclear weapons.松本充郎准教授追悼特集In Honor of the Memory of Professor Mitsuo MATSUMOT

Buckling of Microtubules on a 2D Elastic Medium

We have demonstrated compression stress induced mechanical deformation of microtubules (MTs) on a two-dimensional elastic medium and investigated the role of compression strain, strain rate, and a MT-associated protein in the deformation of MTs. We show that MTs, supported on a two-dimensional substrate by a MT-associated protein kinesin, undergo buckling when they are subjected to compression stress. Compression strain strongly affects the extent of buckling, although compression rate has no substantial effect on the buckling of MTs. Most importantly, the density of kinesin is found to play the key role in determining the buckling mode of MTs. We have made a comparison between our experimental results and the 'elastic foundation model' that theoretically predicts the buckling behavior of MTs and its connection to MT-associated proteins. Taking into consideration the role of kinesin in altering the mechanical property of MTs, we are able to explain the buckling behavior of MTs by the elastic foundation model. This work will help understand the buckling mechanism of MTs and its connection to MT-associated proteins or surrounding medium, and consequently will aid in obtaining a meticulous scenario of the compression stress induced deformation of MTs in cells

Dynamic self-organization and polymorphism of microtubule assembly through active interactions with kinesin

In this study, we show that the energy-dissipative active self-assembly of microtubules (MTs) via a kinesin-based motility system produces various MT assemblies such as bundle-, network-, and ring-shaped structures depending on the initial conditions. Structural polymorphism of the MT assembly is depicted through phase diagrams, and morphogenesis of the MT assembly is discussed based on the following factors: binding force between MTs and motility-driving force from kinesins. This study provides new insights into the energy-dissipative dynamic self-organization of biological systems

Nonlinear friction dynamics on polymer surface under accelerated movement

Nonlinear phenomena on the soft material surface are one of the most exciting topics of chemical physics. However, only a few reports exist on the friction phenomena under accelerated movement, because friction between two solid surfaces is considered a linear phenomenon in many cases. We aim to investigate how nonlinear accelerated motion affects friction on solid surfaces. In the present study, we evaluate the frictional forces between two polytetrafluoroethylene (PTFE) resins using an advanced friction evaluation system. On PTFE surfaces, the normalized delay time δ, which is the time lag in the response of the friction force to the accelerated movement, is observed in the pre-sliding friction process. Under high-velocity conditions, kinetic friction increases with velocity. Based on these experimental results, we propose a two-phase nonlinear model including a pre-sliding process (from the beginning of sliding of a contact probe to the establishment of static friction) and a kinetic friction process. The present model consists of several factors including velocity, acceleration, stiffness, viscosity, and vertical force. The findings reflecting the viscoelastic properties of soft material is useful for various fields such as in the fabrication of clothes, cosmetics, automotive materials, and virtual reality systems as well as for understanding friction phenomena on soft material surfaces