Some examples of noncommutative projective Calabi-Yau schemes

In this article, we construct some examples of noncommutative projective Calabi-Yau schemes by using noncommutative Segre products and quantum weighted hypersurfaces. We also compare them with commutative Calabi-Yau varieties and examples by Kanazawa.Comment: 14 page

Classifying the irreducible components of moduli stacks of torsion free sheaves on K3 surfaces and an application to Brill-Noether theory

In this article, we classify the irreducible components of moduli stacks of torsion free sheaves of rank 2 on K3 surfaces of Picard number 1. For ruled surfaces, the components of moduli stacks of torsion free sheaves were classified by C.Walter. Moreover, by virtue of our result, we classify the irreducible components of Brill-Noether loci of Hilbert schemes of points on K3 surfaces.Comment: 9 page

Visualization of Flows around a Wide Au-Coated Beam in Valving Motion Understood as AC Electroosmosis

Recently, bio-inspired devices have attracted much attention. In particular, elastic valves using AC electroosmosis (ACEO) hold promise for the development of artificial cilia in future microfluidic applications because of their simplicity and high-performance multi-functionality. However, direct evidence of ACEO-driven large valving motion has not been obtained yet. In this study, we report experiments that a wide Au-coated plastic-film beam shows large valving motion in water. By visualizing the flow fields during the motion, we show that the large valving motion of the wide Au-coated beam is understood to be due to ACEO occurring at the edge of the beam. Furthermore, we found that the wide beam was elevated largely by the effect of the vortex flow (understood to be the flow due to ACEO at the beam edge) and the incoming lift flow into the rearward region of the valve. We believe that our findings contribute significantly to realizing new artificial cilia.ArticleJOURNAL OF THE PHYSICAL SOCIETY OF JAPAN.89(4):044401(2020)journal articl

Arrhenius temperature dependence of the crystallization time of deeply supercooled liquids

Usually, supercooled liquids and glasses are thermodynamically unstable against crystallization. Classical nucleation theory (CNT) has been used to describe the crystallization dynamics of supercooled liquids. However, recent studies on overcompressed hard spheres show that their crystallization dynamics are intermittent and mediated by avalanche-like rearrangements of particles, which largely differ from the CNT. These observations suggest that the crystallization times of deeply supercooled liquids or glasses cannot be described by the CNT, but this point has not yet been studied in detail. In this paper, we use molecular dynamics simulations to study the crystallization dynamics of soft spheres just after an instantaneous quench. We show that although the equilibrium relaxation time increases in a super-Arrhenius manner with decreasing temperature, the crystallization time shows an Arrhenius temperature dependence at very low temperatures. This is contrary to the conventional formula based on the CNT. Furthermore, the estimated energy barrier for the crystallization is surprisingly small compared to that for the equilibrium dynamics. By comparing the crystallization and aging dynamics quantitatively, we show that a coupling between aging and crystallization is the key for understanding the rapid crystallization of deeply supercooled liquids or glasses.Comment: 8 pages, 4 figure

Material Cost Minimization Problem for Aluminum Alloy Beam using Beam String Structure

Aluminum alloy is a light-weight material with excellent corrosion resistance but low rigidity. When the aluminum alloy is used to a girder bridge, it takes high costs owing to the increment of its stiffness. Therefore in order to reduce a material cost, the cost minimization problem was performed on beam string structure (BSS) made of the aluminum alloy material based on the results of the topology optimization. We focused on the layout of the BSS and diameter of the cable. The conducted simulation made clear the effectivity of the BSS to the aluminum alloy material for a reduction of material cost and increment of the beam span

Experimental Demonstration of Catching and Releasing Functions of Artificial Cilia Using Induced Charge Electro-Osmosis

Manipulation of an object is essential in microfluidic applications. In this study, we experimentally demonstrate that the artificial cilia having a face-to-face structure shows catching and releasing functions in water through induced charge electro-osmosis. In particular, by the visualization of the flow fields, we show that a target object was pulled into a cilium region by the pull-in flow due to the up-wing motion of the cilia and released by the pop-up flow due to the down-wing motion. We believe that our device is useful to manipulate various particles in microfluidic channels.ArticleJOURNAL OF THE PHYSICAL SOCIETY OF JAPAN.89(5):054401(2020)journal articl

Inactivation of Vibrio vulnificus hemolysin through mutation of the N- or C-terminus of the lectin-like domain

Vibrio vulnificus is an etiological agent causing serious systemic infections in the immunocompromised humans or cultured eels. This species commonly produces a hemolytic toxin consisting of the cytolysin domain and the lectin-like domain. For hemolysis, the lectin-like domain specifically binds to cholesterol in the erythrocyte membrane, and to form a hollow oligomer, the toxin is subsequently assembled on the membrane. The cytolysin domain is essential for the process to form the oligomer. Three-dimensional structure model revealed that two domains connected linearly and the C-terminus was located near to the joint of the domains. Insertion of amino acid residues between two domains was found to cause inactivation of the toxin. In the C-terminus, deletion, substitution or addition of an amino acid residue also elicited reduction of the activity. However, the cholesterol-binding ability was not affected by the mutations. These results suggest that mutation of the C- or N-terminus of the lectin-like domain may result in blockage of the toxin assembly

A Biomechanical Approach to Investigate the Applicability of the Lake-Thomas Theory in Porcine Aorta

Robot-assisted surgeries are procedures where a physician performs surgical maneuvers by operating a robot. One of the main limitations is the difficulty in transferring the surgeon’s multiple skills onto the robotic system. Such skills include the ability to estimate the maximum applicable force before damaging the tissue. To implement this skill onto a robotic system, a mathematical model for tissue damage must be developed. The objective of this study is to measure the fracture characteristic in porcine aorta, to then investigate whether an existing fracture model can be applied onto biological tissues. Due to the similarity in the mechanical response between biological tissues and polymeric materials, the model chosen for this study was the Lake-Thomas model. This is the first paper with the aim of validating this model with biological tissues. Two main findings are reported in this investigation. We found that porcine thoracic aorta tears in a specific way which is directly correlated to the tensile direction. The second finding is that an anisotropic linear relationship exists between the critical tearing energy and the elastic modulus, and the elastic modulus to the -0.5th power. These results are discussed based on the elastin and collagen fibers, as well as established mathematical equations describing polymer mechanic