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Endo M, Tani M, Kurita R. Scraping of foam on a substrate. J Colloid Interface Sci 2023; 650:1612-1618. [PMID: 37494858 DOI: 10.1016/j.jcis.2023.07.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/01/2023] [Accepted: 07/05/2023] [Indexed: 07/28/2023]
Abstract
HYPOTHESIS Foam is not only an industrially important form of matter, but also one of soft jammed system such as colloidal suspensions and emulsion suspensions. Since foams are composed of gas bubbles and liquid, it is expected that the coupling of bubbles and liquid strongly affects rheology of foams, which is different from simple liquids. To reveal this coupling effect and considering the importance of foam applications, we studied the scraping of foam by a rigid plate on a substrate. EXPERIMENT We mainly used 5.0 wt% solution of ionic surfactant TTAB (tetradecyltrimethylammonium bromide). We systematically investigate the scraping behaviors by the rigid plate as a function of scraping velocity, gap height, confinement length, amount of foam and wettability of the substrate. FINDINGS The results show that there are three distinguishable scraping patterns: homogeneous scraping, no scraping, and slendered scraping. These behaviors are clearly different from those of simple liquid systems. Of these, the upper limit of homogeneous scraping could be explained theoretically by the competition between dewetting and shear, which is not previously discussed. Furthermore, the theory is applicable to the scraping of other soft jammed systems such as colloidal and emulsion suspensions.
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Affiliation(s)
- Masaya Endo
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo 192-0397, Japan
| | - Marie Tani
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo 192-0397, Japan.
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo 192-0397, Japan.
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Yanagisawa N, Kurita R. Cross over to collective rearrangements near the dry-wet transition in two-dimensional foams. Sci Rep 2023; 13:4939. [PMID: 36973314 PMCID: PMC10042865 DOI: 10.1038/s41598-023-31577-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 03/14/2023] [Indexed: 03/29/2023] Open
Abstract
Liquid foams respond plastically to external perturbations over some critical magnitude. This rearrangement process is directly related to the mechanical properties of the foams, playing a significant role in determining foam lifetime, deformability, elasticity, and fluidity. In this paper, we experimentally investigate the rearrangement dynamics of foams near a dry-wet transition. When a foam transforms from a dry state to a wet state, it is found that considering collective events, separated T1 events propagate in dry foams, while T1 events occur simultaneously in wet foams. This cross over to collective rearrangements is closely related to the change in local bubble arrangements and mobility. Furthermore, it is also found that a probability of collective rearrangement events occurring follows a Poisson distribution, suggesting that there is little correlation between discrete collective rearrangement events. These results constitute progress in understanding the dynamical properties of soft jammed systems, relevant for biological and material sciences as well as food science.
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Affiliation(s)
- Naoya Yanagisawa
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan.
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan.
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3
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Kobayashi KU, Kurita R. Key connection between gravitational instability in physical gels and granular media. Sci Rep 2022; 12:6290. [PMID: 35428754 PMCID: PMC9012868 DOI: 10.1038/s41598-022-10045-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 03/22/2022] [Indexed: 12/01/2022] Open
Abstract
We study gravitationally-driven (Rayleigh–Taylor-like) instability in physical gels as a model for the behavior of granular media falling under gravity; physical gels have a structural elasticity and may be fluidized, capturing both the solid and liquid properties of granular systems. Though ubiquitous in both industrial and natural contexts, the unique static and dynamic properties of granular media remain poorly understood. Under the action of a gravitational force, granular materials may flow while exhibiting heterogeneous rigidity, as seen during e.g., avalanches or landslides. Though the onset of this gravitational “instability” has been addressed, the mechanism behind its incidence is not yet understood. We find key quantitative similarities between Rayleigh–Taylor-like instability in physical gels and granular systems. In particular, we identify a common scaling law, showing that the instability is chiefly governed by the thickness of the flowable region.
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Abstract
Placing some foam on a vertical surface is a ubiquitous situation, for example, such as in shaving and wall cleaning in daily life, and in egg-laying or making foam nests for some animals or insects in nature. In such a situation, one may prefer that the foam remains in the initial position. Moreover, losing solution via liquid pinch-off from the bottom of the foam is undesirable. To address the pinching off condition and mechanism, we conducted a model experiment: we confined an amount of foam in a Hele-Shaw cell. Two sliding down modes, both with and without liquid pinch-off, were observed under gravity. We fabricated morphology phase diagrams, and theoretically clarified the onset of liquid pinch-off from a foamy droplet.
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Affiliation(s)
- Marie Tani
- Department of Physics, Tokyo Metropolitan University, Tokyo, Japan.
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University, Tokyo, Japan.
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5
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Abstract
Composite materials have been actively developed in recent years because they are highly functional such as lightweight, high yield strength, and superior load response. In spite of importance of the composite materials, mechanisms of the mechanical responses of composites have been unrevealed. Here, in order to understand the mechanical responses of composites, we investigated the origin and nature of the force distribution in heterogeneous materials using a soft particle model. We arranged particles with different softness in a lamellar structure and then we applied homogeneous pressure to the top surface of the system. It is found that the density in each region differently changes and then the density difference induces a nonlinear force distribution. In addition, it is found that the attractive interaction suppresses the density difference and then the force distribution is close to the theoretical prediction. Those findings may lead material designs for functional composite materials.
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Affiliation(s)
- Yuto Tamura
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan
| | - Marie Tani
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan.
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6
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Kobayashi KU, Shinohara R, Kurita R. Mechanism of transient stagnant formation in convection of binary mixtures. J Phys Condens Matter 2021; 33:215101. [PMID: 33780923 DOI: 10.1088/1361-648x/abf2fc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Two-dimensional convection rolls are usually stable near the critical Rayleigh number in single component fluids. However, in binary mixtures, it has been reported that the roll patterns become unstable over time and that stagnant domains are transiently formed. The formation of transient stagnant domains (TSD) occurs in systems where one component is more viscous than the other. Meanwhile, the mechanism of the TSD formation has been unclear yet. Here, we use experiments using well-mixed silicone oils and colloidal suspensions to show that the formation of transient stagnant regions is chiefly related to the concentration dependence of the kinematic viscosity rather than spatially averaged properties. Furthermore, we find that the concentration dependence of density is also related to the formation of stagnant regions. The coupling between density, viscosity and concentration fluctuations may play an important role for thermal convection in multi-component mixtures.
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Affiliation(s)
- Kazuya U Kobayashi
- Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, Japan
| | - Ryoko Shinohara
- Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, Japan
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, Japan
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7
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Abstract
Foams have unique properties that distinguish them from ordinary liquids and gases, and are ubiquitously observed in nature, both in biological systems and industrial products. Foams are known to eventually collapse over time; given their wide-range industrial application, understanding how bubbles in a foam collapse is an important aspect for product longevity and tailoring physical properties. Previously, it was shown that droplets are emitted during the collective bubble collapse, however the mechanism of the droplet emission in a foam is not yet clearly understood. It is directly related to the stability of the foam, thus we quantitatively investigate collapse dynamics in liquid films in a foam, and identify some unique features. When one film breaks, we see that the oscillation of the vertical Plateau border to which it is connected induces anomalous liquid transport from the edge of the border to the center. Once a crack appears near the border and a collapse front is formed, we find that the curvature of the front reverses as it migrates, followed by the emergence and emission of droplets. We elucidate the origins of this behavior and discuss the stability of foams, establishing how the characteristic time scales of the process relate to each other.
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Affiliation(s)
- Naoya Yanagisawa
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-Shi, Tokyo 192-0397, Japan.
| | - Marie Tani
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-Shi, Tokyo 192-0397, Japan.
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-Shi, Tokyo 192-0397, Japan.
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8
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Yanagisawa N, Kurita R. Size distribution dependence of collective relaxation dynamics in a two-dimensional wet foam. Sci Rep 2021; 11:2786. [PMID: 33531566 PMCID: PMC7854744 DOI: 10.1038/s41598-021-82267-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/18/2021] [Indexed: 11/09/2022] Open
Abstract
Foams can be ubiquitously observed in nature and in industrial products. Despite the relevance of their properties to deformation, fluidity, and collapse, all of which are essential for applications, there are few experimental studies of collective relaxation dynamics in a wet foam. Here, we directly observe how the relaxation dynamics changes with increasing liquid fraction in both monodisperse and polydisperse two-dimensional foams. As we increase the liquid fraction, we quantitatively characterize the slowing-down of the relaxation, and the increase of the correlation length. We also find two different relaxation modes which depend on the size distribution of the bubbles. It suggests that the bubbles which are simply near to each other play an important role in large rearrangements, not just those in direct contact. Finally, we confirm the generality of our experimental findings by a numerical simulation for the relaxation process of wet foams.
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Affiliation(s)
- Naoya Yanagisawa
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan.
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan.
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9
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Tsukada T, Kurita R. A topological transition by confinement of a phase separating system with radial quenching. Sci Rep 2019; 9:15764. [PMID: 31673003 PMCID: PMC6823397 DOI: 10.1038/s41598-019-52037-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 10/11/2019] [Indexed: 11/20/2022] Open
Abstract
Physicochemical systems are strongly modified by spatial confinement; the effect is more pronounced the stronger the confinement is, making its influence particularly important nanotechnology applications. For example, a critical point of a phase transition is shifted by a finite size effect; structure can be changed through wetting to a container wall. Recently, it has been shown that pattern formation during a phase separation is changed when a system is heterogeneously quenched instead of homogeneously. Flux becomes anisotropic due to a heterogeneous temperature field; this suggests that the mechanism behind heterogeneous quenching is different from that of homogeneous quenching. Here, we numerically study the confinement effect for heterogeneously quenched systems. We find that the pattern formed by the phase separation undergoes a topological change with stronger confinement i.e. when the height of a simulation box is varied, transforming from a one-dimensional layered pattern to a two-dimensional pattern. We show that the transition is induced by suppression of the heterogeneous flux by spatial confinement. Systems with heterogeneous flux are ubiquitous; the effect is expected to be relevant to a wide variety of non-equilibrium processes under the action of spatial confinement.
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Affiliation(s)
- Tsuyoshi Tsukada
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan.
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10
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Yanagisawa N, Kurita R. In-situ observation of collective bubble collapse dynamics in a quasi-two-dimensional foam. Sci Rep 2019; 9:5152. [PMID: 30914759 PMCID: PMC6435646 DOI: 10.1038/s41598-019-41486-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 03/08/2019] [Indexed: 11/30/2022] Open
Abstract
The stability of foams is an important subject not only for fundamental science, but for applications in daily life. The most destructive phenomenon underpinning foam collapse is a collective bubble collapse, yet the mechanism behind this is unclear. In this study, we clarify the dynamics of the collective bubble collapse in a quasi-two-dimensional foam by in-situ observation with a high speed camera. We find two modes for collective bubble collapse: one is the propagation of liquid film breakage via impact with the stream of another broken liquid film. The other is breakage of a distant liquid film due to penetration by a liquid droplet, emitted by impact with the flow of a broken liquid film. As the liquid fraction increases, the velocity of liquid droplets decreases. Instead of penetration, the liquid droplet bounces like a billiard ball or it is absorbed into other films.
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Affiliation(s)
- Naoya Yanagisawa
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachiouji-shi, Tokyo, 192-0397, Japan.
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11
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Oikawa N, Fukagawa K, Kurita R. Active hole generation in a liquid droplet dissolving into a binary solvent. Soft Matter 2018; 14:4952-4957. [PMID: 29744508 DOI: 10.1039/c8sm00357b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In liquid-liquid dissolution, the critical point of phase separation is determined by the temperature. When the solvent consists of multi-components, in contrast, the mole fractions in the solvent also take on the role of control parameter. In this study an ionic liquid dissolves into a binary solvent composed of ethanol and water. It is found in this system that, near the critical point, a hole is spontaneously created in the droplet of the ionic liquid. The creation of the hole is initiated by a mutual interaction between the concentrations of the ionic liquid and the binary solvent via their affinity. A spatial inhomogeneity of the interfacial tension is induced through an amplification of fluctuation in the concentration due to an instability mechanism, and causes the Marangoni effect to create the hole. The hole moves inside the droplet and consequently leads to the motion of the droplet. The present system provides not only a new type of dissolution process but also a peculiar example of active matter realized in a liquid droplet.
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Affiliation(s)
- Noriko Oikawa
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachioji-shi, Tokyo 192-0397, Japan.
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12
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Kobayashi KU, Kurita R. Ubiquitous transient stagnant domain formation during thermal convection in a well-mixed two component fluid with large viscosity difference. Sci Rep 2017; 7:12983. [PMID: 29021561 PMCID: PMC5636821 DOI: 10.1038/s41598-017-13409-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/22/2017] [Indexed: 11/21/2022] Open
Abstract
The formation of a transient stagnant domain in the presence of thermal convection was previously reported near the sol-gel transition temperature of a gelatin solution. The transient stagnant domain is observed near a critical Rayleigh number where a "roll" pattern is usually stable. It is important to understand the origin of the transient stagnant domain formation since it induces a large deformation of convection patterns; the nature of the formation of the transient stagnant domain remains unclear. Here, we observe thermal convection using several different fluids and find that stagnant domain formation is ubiquitous in two component mixtures. In addition, we find that difference in viscosity between the two components is crucial for transient stagnant domain formation, more so than the concentration gradient induced by the temperature gradient.
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Affiliation(s)
- Kazuya U Kobayashi
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachioji-shi, Tokyo, 192-0397, Japan.
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University, 1-1 Minamioosawa, Hachioji-shi, Tokyo, 192-0397, Japan
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13
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Kurita R, Mitsui S, Tanaka H. Response of Soft Continuous Structures and Topological Defects to a Temperature Gradient. Phys Rev Lett 2017; 119:108003. [PMID: 28949161 DOI: 10.1103/physrevlett.119.108003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Indexed: 06/07/2023]
Abstract
Thermophoresis, which is mass transport induced by a temperature gradient, has recently attracted considerable attention as a new way to transport materials. So far the study has been focused on the transport of discrete structures such as colloidal particles, proteins, and polymers in solutions. However, the response of soft continuous structures such as membranes and gels to a temperature gradient has been largely unexplored. Here we study the behavior of a lamellar phase made of stacked surfactant bilayer membranes under a temperature gradient. We find the migration of membranes towards a low-temperature region, causing the increase in the degree of membrane undulation fluctuations towards that direction. This is contrary to our intuition that the fluctuations are weaker at a lower temperature. We show that this can be explained by temperature-gradient-induced migration of membranes under the topological constraint coming from the connectivity of each membrane. We also reveal that the pattern of an edge dislocation array formed in a wedge-shaped cell can be controlled by a temperature gradient. These findings suggest that application of a temperature gradient provides a novel way to control the organization of soft continuous structures such as membranes, gels, and foams, in a manner essentially different from the other types of fields, and to manipulate topological defects.
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Affiliation(s)
- Rei Kurita
- Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-City, Tokyo 192-0397, Japan
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Shun Mitsui
- Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-City, Tokyo 192-0397, Japan
| | - Hajime Tanaka
- Department of Fundamental Engineering, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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14
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Abstract
The states of foam are empirically classified into dry foam and wet foam by the volume fraction of the liquid. Recently, a transition between the dry foam state and the wet foam state has been found by characterizing the bubble shapes [Furuta et al., Sci. Rep. 6, 37506 (2016)2045-232210.1038/srep37506]. In the literature, it is indirectly ascertained that the transition from the dry to the wet form is related to the onset of the rearrangement of the bubbles, namely, the liquid fraction at which the bubbles become able to move to replace their positions. The bubble shape is a static property, and the rearrangement of the bubbles is a dynamic property. Thus, we investigate the relation between the bubble shape transition and the rearrangement event occurring in a collapsing process of the bubbles in a quasi-two-dimensional foam system. The current setup brings a good advantage to observe the above transitions, since the liquid fraction of the foam continuously changes in the system. It is revealed that the rearrangement of the bubbles takes place at the dry-wet transition point where the characteristics of the bubble shape change.
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Affiliation(s)
- Rei Kurita
- Department of Physics, Tokyo Metropolitan University, Minamioosawa, Hachioji-shi, Tokyo 192-0397, Japan
| | - Yujiro Furuta
- Department of Physics, Tokyo Metropolitan University, Minamioosawa, Hachioji-shi, Tokyo 192-0397, Japan
- Department of Physics, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Naoya Yanagisawa
- Department of Physics, Tokyo Metropolitan University, Minamioosawa, Hachioji-shi, Tokyo 192-0397, Japan
| | - Noriko Oikawa
- Department of Physics, Tokyo Metropolitan University, Minamioosawa, Hachioji-shi, Tokyo 192-0397, Japan
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15
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Kurita R. Experimental study of the relationship between local particle-size distributions and local ordering in random close packing. Phys Rev E Stat Nonlin Soft Matter Phys 2015; 92:062305. [PMID: 26764690 DOI: 10.1103/physreve.92.062305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Indexed: 06/05/2023]
Abstract
We experimentally study the structural properties of a sediment of size distributed colloids. By determining each particle size using a size estimation algorithm, we are able to investigate the relationship between local environment and local ordering. Our results show that ordered environments of particles tend to generate where the local particle-size distribution is within 5%. In addition, we show that particles whose size is close to the average size have 12 coordinate neighbors, which matches the coordination number of the fcc and hcp crystals. On the other hand, bcc structures are observed around larger particles. Our results represent experiments to show a size dependence of the specific ordering in colloidal systems.
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Affiliation(s)
- Rei Kurita
- Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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16
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Fujihara M, Inoue R, Kurita R, Taniuchi T, Motoyui Y, Shin S, Komori F, Maniwa Y, Shinohara H, Miyata Y. Selective Formation of Zigzag Edges in Graphene Cracks. ACS Nano 2015; 9:9027-9033. [PMID: 26288323 DOI: 10.1021/acsnano.5b03079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the thermally induced unconventional cracking of graphene to generate zigzag edges. This crystallography-selective cracking was observed for as-grown graphene films immediately following the cooling process subsequent to chemical vapor deposition (CVD) on Cu foil. Results from Raman spectroscopy show that the crack-derived edges have smoother zigzag edges than the chemically formed grain edges of CVD graphene. Using these cracks as nanogaps, we were also able to demonstrate the carrier tuning of graphene through the electric field effect. Statistical analysis of visual observations indicated that the crack formation results from uniaxial tension imparted by the Cu substrates together with the stress concentration at notches in the polycrystalline graphene films. On the basis of simulation results using a simplified thermal shrinkage model, we propose that the cooling-induced tension is derived from the transient lattice expansion of narrow Cu grains imparted by the thermal shrinkage of adjacent Cu grains.
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Affiliation(s)
- Miho Fujihara
- Department of Chemistry, Nagoya University and Institute for Advanced Research , Nagoya 464-8602, Japan
| | - Ryosuke Inoue
- Department of Physics, Tokyo Metropolitan University , Hachioji, Tokyo 192-0397, Japan
| | - Rei Kurita
- Department of Physics, Tokyo Metropolitan University , Hachioji, Tokyo 192-0397, Japan
| | - Toshiyuki Taniuchi
- Institute for Solid State Physics, The University of Tokyo , Kashiwa, Chiba 277-8581, Japan
| | - Yoshihito Motoyui
- Institute for Solid State Physics, The University of Tokyo , Kashiwa, Chiba 277-8581, Japan
| | - Shik Shin
- Institute for Solid State Physics, The University of Tokyo , Kashiwa, Chiba 277-8581, Japan
| | - Fumio Komori
- Institute for Solid State Physics, The University of Tokyo , Kashiwa, Chiba 277-8581, Japan
| | - Yutaka Maniwa
- Department of Physics, Tokyo Metropolitan University , Hachioji, Tokyo 192-0397, Japan
| | - Hisanori Shinohara
- Department of Chemistry, Nagoya University and Institute for Advanced Research , Nagoya 464-8602, Japan
| | - Yasumitsu Miyata
- Department of Physics, Tokyo Metropolitan University , Hachioji, Tokyo 192-0397, Japan
- JST-PRESTO , Kawaguchi, Saitama 332-0012, Japan
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17
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Kurita R, Ruffner DB, Weeks ER. Measuring the size of individual particles from three-dimensional imaging experiments. Nat Commun 2012; 3:1127. [DOI: 10.1038/ncomms2114] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 09/04/2012] [Indexed: 12/21/2022] Open
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18
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Kurita R, Weeks ER. Incompressibility of polydisperse random-close-packed colloidal particles. Phys Rev E Stat Nonlin Soft Matter Phys 2011; 84:030401. [PMID: 22060321 DOI: 10.1103/physreve.84.030401] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Revised: 08/04/2011] [Indexed: 05/31/2023]
Abstract
We use confocal microscopy to study the compressibility of a random-close-packed sample of colloidal particles. To do this, we introduce an algorithm to estimate the size of each particle. Taking into account their sizes, we compute the compressibility of the sample as a function of wave vector q, and find that this compressibility vanishes linearly as q→0, showing that the packing structure is incompressible. The particle sizes must be considered to calculate the compressibility properly. These results also suggest that the experimental packing is hyperuniform.
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Affiliation(s)
- Rei Kurita
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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19
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Kurita R, Weeks ER. Glass transition of two-dimensional binary soft-disk mixtures with large size ratios. Phys Rev E Stat Nonlin Soft Matter Phys 2010; 82:041402. [PMID: 21230272 DOI: 10.1103/physreve.82.041402] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 08/19/2010] [Indexed: 05/30/2023]
Abstract
We simulate binary soft-disk systems in two dimensions and investigate how the dynamics slow as the area fraction is increased toward the glass transition. The "fragility" quantifies how sensitively the relaxation time scale depends on the area fraction, and the fragility strongly depends on the composition of the mixture. We confirm prior results for mixtures of particles with similar sizes, where the ability to form small crystalline regions correlates with fragility. However, for mixtures with particle size ratios above 1.4, we find that the fragility is not correlated with structural ordering, but rather with the spatial distribution of large particles. The large particles have slower motion than the small particles and act as confining "walls" which slow the motion of nearby small particles. The rearrangement of these confining structures governs the lifetime of dynamical heterogeneity, that is, how long local regions exhibit anomalously fast or slow behavior. The strength of the confinement effect is correlated with the fragility and also influences the aging behavior of glassy systems.
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Affiliation(s)
- Rei Kurita
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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Abstract
A collection of spherical particles can be packed tightly together into an amorphous packing known as "random close packing" (RCP). This structure is of interest as a model for the arrangement of molecules in simple liquids and glasses, as well as the arrangement of particles in sand piles. We use confocal microscopy to study the arrangement of colloidal particles in an experimentally realized RCP state. We image a large volume containing more than 450,000 particles with a resolution of each particle position to better than 0.02 particle diameters. While the arrangement of the particles satisfies multiple criteria for being random, we also observe a small fraction (less than 3%) of tiny crystallites (4 particles or fewer). These regions pack slightly better and are thus associated with locally higher densities. The structure factor of our sample at long length scales is nonzero, S(0)=0.049±0.008, suggesting that there are long wavelength density fluctuations in our sample. These may be due to polydispersity or tiny crystallites. Our results suggest that experimentally realizable RCP systems may be different from simulated RCP systems, in particular, with the presence of these long wavelength density fluctuations.
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Affiliation(s)
- Rei Kurita
- Department of Physics, Emory University, Atlanta, Georgia 30322, USA
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Kurita R, Murata KI, Tanaka H. Control of fluidity and miscibility of a binary liquid mixture by the liquid-liquid transition. Nat Mater 2008; 7:647-652. [PMID: 18604215 DOI: 10.1038/nmat2225] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Accepted: 06/05/2008] [Indexed: 05/26/2023]
Abstract
Matter in its liquid state is convenient for processing and controlling chemical reactions, owing to its fluidity. Recently much evidence has been accumulated for the existence of a liquid-liquid transition (LLT) in single-component liquids. Here, we report that we can control, by the LLT of a molecular liquid, triphenyl phosphite (TPP), the fluidity and miscibility of its mixture with another molecular liquid. For a mixture of TPP with toluene or aniline, we find that both liquid I and II mix well and liquid II remains in a 'liquid' state, in contrast to pure TPP, where liquid II is a non-ergodic amorphous state. This is the first example of a 'true' LLT in a molecular liquid. Furthermore, we find demixing induced by the LLT for a mixture of TPP with diethyl ether or ethanol. These findings will open a new phase of research towards various applications of the LLT.
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Affiliation(s)
- Rei Kurita
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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Kim YT, Yoshida H, Kojima M, Kurita R, Nishii W, Muramatsu T, Ito H, Park SJ, Takahashi K. The Effects of Mutations in the Carboxyl-Terminal Region on the Catalytic Activity of Escherichia coli Signal Peptidase I. J Biochem 2008; 143:237-42. [DOI: 10.1093/jb/mvm212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kurita R, Tanaka H. Control of the liquid-liquid transition in a molecular liquid by spatial confinement. Phys Rev Lett 2007; 98:235701. [PMID: 17677919 DOI: 10.1103/physrevlett.98.235701] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Indexed: 05/16/2023]
Abstract
Generally, phase transitions are seriously affected by spatial confinement. This effect is important for its own sake, but also for applications to nanotechnology. Here we report the first systematic experimental study on confinement effects on a liquid-liquid transition of a molecular liquid. We found that one liquid can be transformed into another purely by spatial confinement. This indicates that the liquid state cannot be specified by the temperature and pressure alone, but it is also affected by its size in a discontinuous manner: the phase of a liquid in a narrow space can, in principle, be different from that in the bulk. This finding would deepen our basic understanding of the liquid state.
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Affiliation(s)
- Rei Kurita
- Institute of Industrial Science, University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
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Abstract
Recently it has been revealed that even a single-component liquid can have more than two liquid states. The transition between these liquid states is called the "liquid-liquid transition." Most known liquid-liquid transitions occur at temperatures and pressures which are difficult to access experimentally, so the physical nature of the transition, particularly the kinetics, has remained elusive. However, the recent discovery of liquid-liquid transitions in molecular liquids opens up a possibility to study the kinetics in detail. Here, we report the first phase field simulation on the kinetics of a liquid-liquid transition and its direct comparison with experimental results of the molecular liquids. Both nucleation-growth-type and spinodal-decomposition-type liquid-liquid transformation observed experimentally are well reproduced by numerical simulation based on a two-order-parameter model of liquid that regards the liquid-liquid transition as the cooperative formation of locally favored structures. Thus, phase field calculations may allow us to predict the kinetics of liquid-liquid transitions and the resulting spatiotemporal change of various physical properties of the liquid, such as density and refractive index.
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Affiliation(s)
- Rei Kurita
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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Kang X, Xiao X, Harata M, Bai Y, Nakazaki Y, Soda Y, Kurita R, Tanaka T, Komine F, Izawa K, Kunisaki R, Setoyama M, Nishimori H, Natsume A, Sunamura M, Lozonshi L, Saitoh I, Tokino T, Asano S, Nakamura Y, Tani K. Antiangiogenic activity of BAI1 in vivo: implications for gene therapy of human glioblastomas. Cancer Gene Ther 2005; 13:385-92. [PMID: 16244591 DOI: 10.1038/sj.cgt.7700898] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glioblastomas are the most common primary brain tumors in adults. These tumors exhibit a high degree of vascularization, and malignant progression from astrocytoma to glioblastoma is often accompanied by increased angiogenesis and the upregulation of vascular endothelial growth factor and its receptors. In this study, we investigated the in vivo antiangiogenic and antitumor effects of brain-specific angiogenesis inhibitor 1 (BAI1) using human glioblastoma cell lines. Glioblastoma cells were transduced with an adenoviral vector encoding BAI1 (AdBAI1), and Northern and Western blot analyses, respectively, demonstrated BAI1 mRNA and protein expression in the transduced tumor cells. Using an in vivo neovascularization assay, we found that angiogenesis surrounding AdBAI1-transduced glioblastoma cells transplanted into transparent skinfold chambers of SCID mice was significantly impaired compared to control treated cells. Additionally, in vivo inoculation with AdBAI1 of established subcutaneous or intracerebral transplanted tumors significantly impaired tumor growth and promoted increased mouse survival. Morphologically, the tumors exhibited signs of impaired angiogenesis, such as extensive necrosis and reduced intratumoral vascular density. Taken together, these data strongly indicate that BAI1 may be an excellent gene therapy candidate for the treatment of brain tumors, especially human glioblastomas.
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Affiliation(s)
- X Kang
- Division of Molecular Therapy, Advanced Clinical Research Center, The University of Tokyo, Tokyo, Japan
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Kurita R, Tanaka H. Control of the fragility of a glass-forming liquid using the liquid-liquid phase transition. Phys Rev Lett 2005; 95:065701. [PMID: 16090963 DOI: 10.1103/physrevlett.95.065701] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Indexed: 05/03/2023]
Abstract
When a liquid approaches its glass-transition temperatures T(g), the structural relaxation time tau dramatically increases. This basic feature is ubiquitous, but this increase of tau can be classified between strong and fragile extremes using T(g) as a scaling parameter. Liquids, whose tau obeys the Arrhenius law, are called "strong," while "fragile" liquids have the super-Arrhenius behavior. Here we report the first continuous control of the fragility of liquid of the same material over a wide range of fragility, using a continuous liquid-liquid transition. Our study clearly demonstrates that the fragility is not a material-specific quantity, but is controlled by the order parameter governing the liquid-liquid transition, which may be the fraction of locally favored structures in the liquid.
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Affiliation(s)
- Rei Kurita
- Institute of Industrial Science, University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
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Abstract
Contrary to the conventional wisdom that there is only one unique liquid state for any material, recent evidence suggests that there can be more than two liquid states even for a single-component substance. The transition between these liquid states is called a liquid-liquid phase transition. We report the detailed experimental investigation on the kinetics of the continuous spinodal-decomposition-type transformation of one liquid into another for triphenyl phosphite. From the analysis of the linear regime, we found that the correlation length, xi, of fluctuations of the relevant order parameter diverges as xi = xi(0)[(T(SD) - T)/T(SD)](-nu) (where xi(0) = 60 nm and nu = 0.5) while approaching the spinodal temperature, T(SD). This is an indication of a critical-like anomaly associated with the liquid-liquid transition. We also revealed that the order parameter governing the liquid-liquid transition must be of a nonconserved nature.
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Affiliation(s)
- Rei Kurita
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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Abstract
We found both nucleation-growth-type and spinodal-decomposition-type transformation from one liquid state to another in a "molecular liquid," triphenyl phosphite (TPP). Binodal and spinodal temperatures of this transition at ambient pressure were determined by the characteristics of morphological evolution, domain-growth kinetics, and rheological evolution. Furthermore, a distinct thermal signature of the glass transition of a second liquid was also detected in addition to that of an ordinary liquid. These findings strongly suggest the existence of a liquid-liquid transition; more precisely, a transformation of one supercooled liquid to a glassy state of another liquid, in TPP.
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Affiliation(s)
- Hajime Tanaka
- Institute of Industrial Science, University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
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Abstract
We developed a real-time electrochemical imaging method that uses a multiple enzyme-modified microelectrode. The method will enable the investigation of the functions of biological materials and cells. To test its effectiveness, we imaged the two-dimensional concentration distribution for hydrogen peroxide and L-glutamate in a standard solution. The multiple electrode consists of an 8 x 8 array of 30 x 30 microm2 carbon micro electrode. Each electrode was connected to a 64-channel potentiostat that could apply a potential to all electrodes at the same time. The multiple electrode was coated with an Os-polyvinylpyridine based polymer (Os-gel) containing horse radish peroxidase (HRP) to detect hydrogen peroxide, which is a very common product of oxidase enzyme. When measuring glutamate, which is a well-known neurotransmitter in the mammalian central nerve system, we modified the electrode with a bilayer of Os-gel-HRP and GluOx. The detection limit of our method was 1 microM and images of the glutamate concentration-distribution changes induced by local injection of glutamate through microcapillary were obtained in real time.
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Affiliation(s)
- K Hayashi
- NTT Lifestyle and Environmental Technology Laboratories, Wakamiya, Atsugi, Kanagawa, Japan.
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Liu Z, Niwa O, Kurita R, Horiuchi T. Miniaturized thin-layer radial flow cell with interdigitated ring-shaped microarray electrode used as amperometric detector for capillary electrophoresis. J Chromatogr A 2000; 891:149-56. [PMID: 10999634 DOI: 10.1016/s0021-9673(00)00632-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A chip-type thin-layer radial flow cell was developed as an amperometric detector for capillary electrophoresis. We fabricated a carbon film-based interdigitated ring-shaped array (IDRA) microelectrode with a 2 microm bandwidth and an almost 1 microm gap on a glass plate and used it as a working electrode. A fused-silica capillary was arranged above the IDRA electrode using a guide hole drilled through the acryl plate that formed the flow cell lid. A flow channel for use in connecting the outlet capillary was also fabricated in the acryl plate. We characterized the analytical performance of the IDRA electrode in the microchip flow cell in terms of linear concentration range, sensitivity and concentration detection limit. We achieved a collection efficiency and catechol redox cycle at the IDRA microelectrode of 65% and 1.71, respectively, and thus a high sensitivity and low detection limit of 392.9 pA/microM and 15 nM for dopamine hydrochloride. We examined the reproducibility of the detector and found that the run-to-run and detector-to-detector relative standard deviations were both less than 10%.
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Affiliation(s)
- Z Liu
- NTT Lifestyle and Environmental Technology Laboratories, Atsugi, Kanagawa, Japan
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Hasegawa O, Matsumoto S, Iino M, Kurita R, Kubota Y. [Comparison of electrophysiological findings between CIDP and HMSN-1]. No To Shinkei 1999; 51:411-4. [PMID: 10396746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
Chronic inflammatory demyelinating polyneuropathy (CIDP) and hereditary motor sensory neuropathy type 1 (HMSN-1) are representative myelinopathies. In order to differentiate changes in acquired and congenital demyelinating neuropathies, we studied electrophysiologically 9 patients with active phase of CIDP (36.0 +/- 17.6 years old; mean +/- SD) and 7 patients with genetically-proven HMSN-1 A (56.0 +/- 13.6 years old). Motor conduction studies demonstrated longitudinal uniformity in HMSN-1, contrariwise focal conduction block or conduction delay in CIDP. The mean median nerve conduction velocity in the forearm segment and the mean CMAP amplitude stimulated at the wrist were not different between CIDP and HMSN-1 group; 31.8 +/- 7.2 m/sec and 5.6 +/- 2.8 mV in CIDP, and 26.7 +/- 9.8 m/sec and 3.2 +/- 2.6 mV in HMSN-1, respectively. Upper extremity polyneuropathy index (PNI), a mean percentage of normal for 6 indices concerning to the velocity and latency over two nerves obtained by motor conduction studies, was equal and around 50% on the average in each group. Conduction blocks were presented in 7 patients with CIDP and only one patient with HMSN-1. No sensory nerve action potential was recorded in 6 out of 9 patients with CIDP, and in 6 out of 7 patients with HMSN-1. Intrafascicular neurography of the median nerve, stimulated at the wrist and recorded from intrafascicularly inserted microelectrode at the elbow, revealed irregular multiphasic waves which signify severe temporal dispersion. Maximum conduction velocity was similarly reduced to 48 m/sec in CIDP and 44 m/sec in HMSN-1 on the average, but in one patient with HMSN-1 it was maintained to 63 m/sec with conspicuous temporal dispersion of the waveform. Amplitude of the compound nerve action potential (CNAP) decreased more (p < 0.01) in HMSN-1 (26 +/- 11 micro V) than in CIDP (72 +/- 25 micro V). Temporal dispersion of CNAP was prominent in HMSN-1 than in CIDP. In conclusion, electrophysiological changes were more homogeneous in the longitudinal distribution but more heterogeneous in the cross-sectional distribution in HMSN-1 than in CIDP.
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Affiliation(s)
- O Hasegawa
- Department of Neurology, Yokohama City University School of Medicine, Japan
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Hasegawa O, Matsumoto S, Iino M, Kurita R, Yoshii T. [Superiority of intrafascicular neurography over conventional nerve conduction studies in evaluating axonal degeneration]. No To Shinkei 1999; 51:313-6. [PMID: 10363265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
We investigated conventional motor and sensory nerve conduction studies (MCS & SCS) with regard to the sensitivity in detecting axonopathies. Twelve patients with axonal type of polyneuropathy, 2 vincristin neuropathy and 10 cisplatin neuropathy, were examined by MCS & SCS. Their data were compared with those by intrafascicular microneurography (MNG) of the median nerve. Nerve conduction velocities were within normal limits or slightly reduced to 87-99% of the normal. Amplitude of compound muscle action potential (CMAP) by MCS decreased to 4 or 5 mV in vincristin neuropathy, though cisplatin neuropathy presented normal amplitude. Amplitude of sensory nerve action potential (SNAP) by SCS was undetected in one median nerve and in three sural nerves. While, compound nerve action potential (CNAP) by MNG was all recorded, and presented the amplitude value of below 150 microV in seven patients. The waveform was normal or mild neuropathic pattern. No patients presented normal CNAP amplitude and reduced SNAP amplitude. But there were three patients who had normal SNAP amplitude and reduced CNAP amplitude. In SCS we could recognize abnormal only after CNAP amplitude by MNG dropped to below 100 microV. Cisplatin neuropathy demonstrates reduction of CNAP or SNAP amplitude, and vincristin neuropathy further presents reduction of CMAP amplitude. Evaluation of axonopathy is best achieved by nerve action potential amplitude. Conventional surface electrode methods are available for this purpose, but MNG is more sensitive and is capable of quantitative analysis even in severely damaged nerves.
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Affiliation(s)
- O Hasegawa
- Department of Neurology, Yokohama City University School of Medicine, Fukuura, Japan
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Niwa O, Horiuchi T, Kurita R, Torimitsu K. On-line electrochemical sensor for selective continuous measurement of acetylcholine in cultured brain tissue. Anal Chem 1998; 70:1126-32. [PMID: 9530003 DOI: 10.1021/ac970257o] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
An on-line acetylcholine (ACh) sensor was developed in order to determine extracellular ACh concentrations without interference from choline (Ch). The sensor is composed of a small-volume enzymatic prereactor (22-microL inner volume) in which choline oxidase and catalase are immobilized in series. Carbon electrodes were modified with an acetylcholine esterase (AChE), choline oxidase (ChOx), and osmium poly(vinylpyridine)-based redox polymer containing horseradish peroxidase (Os-gel-HRP). The sensor sensitivity was 43.7 nA/microM (+/- 0.15, n = 3) for ACh under optimized conditions. Almost no response was seen when 100 microM Ch was continuously injected. The detection limit for ACh with the sensor was comparable to that obtained using liquid chromatography with electrochemical detection combined with an enzymatic reactor. The electrical stimulation of cultured rat hippocampal tissue resulted in an extracellular ACh increase of 20 nM (+/- 11 nM, n = 3). This increase was observed continuously with our online sensor combined with a microcapillary sampling probe located very close to the tissue. The continuous measurement of ACh and Ch using a split disk carbon film dual electrode in which one electrode surface was modified with ChOx/Os-gel-HRP and the other with AChE-ChOx/Os-gel-HRP bilayer film was also demonstrated to improve the response time by eliminating the prereactor.
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Affiliation(s)
- O Niwa
- NTT Basic Research Laboratories, Kanagawa, Japan
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Abstract
We report the first on-line electrochemical sensor for the continuous measurement of gamma-aminobutyric acid (GABA), which is a well-known inhibitory neurotransmitter in the nervous system. The sensor is composed of a glutamate oxidase (GluOx) and catalase immobilized small-volume enzymatic reactor and a glassy carbon (GC) electrode modified with a top layer film consisting of gabase and GluOx coimmobilized bovine serum albumin and an Ospoly(vinylpyrridine) bottom layer film containing horseradish peroxidase. The response of the sensor depends on the alpha-ketoglutarate concentration and is almost saturated when its concentration is 100 times higher than GABA. The sensor exhibits a sensitivity of 1.56 nA/microM for GABA under optimized conditions and shows almost no response when 10 microM glutamate is continuously injected. A detection limit of 0.1 microM is obtained with a linear range of 0.1-10 microM. GABA can be measured in the absence of alpha-ketoglutarate when there is L-glutamate in the sample solution, which is a typical condition for the extracellular measurement of cultured nerve cells.
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Affiliation(s)
- O Niwa
- NTT Basic Research Laboratories, Kanagawa, Japan
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Kubota Y, Hasegawa O, Matsumoto S, Kurita R, Komiyama A, Kikuchi N. [Electrophysiological evaluation of polyneuropathy in juvenile insulin dependent diabetics]. No To Shinkei 1997; 49:983-5. [PMID: 9396028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Thirty patients with juvenile insulin dependent diabetes mellitus (IDDM) were electrophysiologically evaluated. In addition to the conventional motor and sensory nerve conduction studies, intrafascicular microneurography was performed in the median nerve. In this method a tungsten microelectrode was inserted into the median nerve trunk at the elbow, and a compound nerve action potential (CNAP) was recorded with supramaximal electrical stimulation at the wrist. The subjects' age ranged from 8 to 31 years with an average (SD) of 15.4 (6.2) years; the disease duration varied from 1 to 23 years with an average (SD) of 8.3 (5.8) years. Polyneuropathy index (PNI), expressed as a mean percentage of the normal for twelve indices over the four nerves obtained by motor conduction studies, was 93.9% on the average in patients with IDDM. The mean amplitude of CNAP obtained by intrafascicular microneurography was 417 microV. These results indicate that neuropathy in IDDM is milder than that in adult non-insulin dependent diabetes mellitus (NIDDM). The mean value of PNI decreased at a rate of 0.56% per year; the mean glycosylated hemoglobin (A1c) level was as high as 8.2 +/- 0.9%, findings consistent with those of the previous analysis of adult patients with NIDDM. The PNI value had a significant negative correlation with the duration of diabetes mellitus (p < 0.001) and with mean glycosylated hemoglobin (A1c) level (p < 0.01). CNAP amplitude had a tendency to correlate with duration of diabetes mellitus (p < 0.1). In patients with IDDM we can tell exactly when the disease occurred. Progression of neuropathy in juvenile IDDM was identical to that of adult NIDDM. Careful management of diabetes mellitus is of importance to prevent the progression of neuropathy.
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Affiliation(s)
- Y Kubota
- Division of Clinical Laboratory, Yokohama City University Hospital, Japan
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Hasegawa O, Komiyama A, Kubota-Nara Y, Matsumoto S, Kurita R. [An analysis of A-wave with slowed conduction in its afferent and efferent pathways below the branching point]. Rinsho Shinkeigaku 1996; 36:488-91. [PMID: 8741356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Motor nerve conduction study was carried out in a 59-year-old woman with 20 years' history of diabetes mellitus. When her right ulnar nerve was stimulated at the wrist, the needle electrode penetrated into the first dorsal interosseous muscle revealed an existence of A-wave. Following characteristics were observed: (1) A-wave appeared with more than 20 mA of the stimuli, in a all-or-none manner at the latency of 54 msec; (2) when stimulated more than 50 mA, A-wave jumped at 10 msec of the latency and were superimposed upon the M-wave; (3) A-wave had a stable latency; (4) when stimulated at the more proximal site, A-wave had longer latency (direct pathway) by strong stimuli, and the potential had shorter latency (indirect pathway) by weak stimuli; and (5) A-wave was not collided by paired stimuli. A-wave conduction velocity was slower than 10 m/sec in the distal part of the reflecting point both in afferent and efferent pathways. This report is the first to show strikingly slowed conduction of A-wave distal to the reflecting point compared to the proximal portion. This fact supports the thesis that A-wave is generated from the branching of immature regenerating fibers. M-wave conduction velocity also decreased around the reflecting point of the A-wave, suggesting that, in addition to moderate diabetic polyneuropathy, entrapment at the cubital tunnel may be involved in generating this A-wave.
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Affiliation(s)
- O Hasegawa
- Department of Neurology, Yokohama City University School of Medicine, Japan
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Matsumoto M, Hasegawa O, Kurita R, Komiyama A, Kubota-Nara Y. [Electrophysiological assessment of median sensory nerve function in HMSN type I by intraneural neurography]. Rinsho Shinkeigaku 1996; 36:52-4. [PMID: 8689791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Microneurography (MNG) performed in the forearm segment of the median nerve enabled us to assess compound nerve action potentials reflecting the density of large myelinated sensory fibers around the microelectrode. We examined sensory nerve function of the median nerve in seven patients with hereditary motor and sensory neuropathy type I (HMSN-I) with conventional surface-electrode technique and MNG. In six of seven patients sensory nerve action potentials were not elicited with the surface-electrode method. In contrast, compound nerve action potentials (CNAPs) were evoked in all seven patients with MNG. Although the normal waveform of CNAP is characterized by a large triphasic wave with subsequent small multiphasic waves, the triphasic wave was diminished and prolonged small multiphasic waves were prominent in the patients. Maximal nerve conduction velocity and amplitude of the wave were decreased to 69% and 9% of age-matched control values, respectively. These changes detected in patients with HMSN-I could be interpreted as a result of large myelinated fiber loss and segmental demyelination of sensory nerves. We showed that sensory fiber dysfunction in HMSN-I could be quantitatively evaluated with MNG, even though the sensory action potential was not elicited with the surface-electrode method.
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Affiliation(s)
- M Matsumoto
- Department of Neurology, Yokohama City University School of Medicine
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Hasegawa O, Komiyama A, Kubota-nara Y, Matsumoto S, Kurita R. [Midmotoraxonal reexcitation observed in a patient with hereditary motor and sensory neuropathy (HMSN) type IA]. Rinsho Shinkeigaku 1996; 36:65-7. [PMID: 8689795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We report a unique late motor unit potential observed in a patient with hereditary motor and sensory neuropathy (HMSN) type IA. The characteristics of the potential were as follows; (1) constant appearance with more than 20 mA of the stimuli, without disappearance with supramaximal stimuli, (2) constant wave-form and amplitude, (3) shorter latency with more proximal stimulation (indirect pathway), (4) remarkable fluctuation of the latency, and (5) disappearance with paired stimuli. The characteristics (1)-(3) correspond to Tomasulo's "peripheral late wave". But our late potential had fluctuation in its latency and was cancelled by paired stimuli, which indicates that this potential originated from the reflection at the midmotoraxonal demyelinating portion. Demyelinating portion is electrically unstable, where the duration of action potential is elongated. Consequently, nerve action potential at that site continues even after the refractory period is over at the adjacent distal portion, which might be the reason that this reflecting potential was evoked.
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Affiliation(s)
- O Hasegawa
- Department of Neurology, Yokohama City University School of Medicine
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Hasegawa O, Kurita R, Kubota-Nara Y, Ohta S, Komiyama A. [Stimulus effect of submaximal trains of impulses on nerves]. No To Shinkei 1996; 48:27-30. [PMID: 8679315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Although the occurrence of rate-dependent conduction block upon exposure to supramaximal stimuli is a well-known phenomenon, changes in the stimulus effect of submaximal trains of impulses on nerves remain unknown. To investigate changes in the stimulus effect, we evaluated median nerve action potentials using various frequencies of impulse trains. The subjects were 12 healthy controls and 9 patients with diabetic polyneuropathy. A tungsten microelectrode was inserted into the median nerve trunk at the elbow. Weak stimuli that produced 10 microV compound nerve action potentials were repeated. Each value recorded is the average of 20 trials. Repetition of 1- to 5-Hz stimuli yielded the same average wave, but above 7-Hz, the stimuli produced a diminution in amplitude and slight prolongation of the latency of each peak. This was most prominent with 50-Hz or 100-Hz repeated stimuli. The potentials changed amplitude with a waxing and waning pattern, and gradually stabilized at a lower level. The averaged wave corresponded to the record of reduced stimuli at 0.6 mA, maximally. Paired stimuli at an interval of less than 5 msec were equivalent to a relative refractory period, whereas at an interval of 4-18 msec they were equivalent to a supernormal period, and at 12-90 msec, to a subnormal period. The 'jumping' (unexpected shortening of the latency of a potential in response to increased stimulus intensity) of a single nerve unit was provoked or released corresponding to these periods. No differences were found between healthy individuals and patients with diabetic polyneuropathy. As a consequence of electrogenic Na+/K+ pumping, a three-Na+ ion efflux occurred instead of a two-K+ ion influx. Thus, repeated high-frequency impulses induced membrane hyperpolarization that reduced the stimulus effect on nerves. With trains of impulses at a frequency of 100-Hz, which corresponds to a stimulus every 10 msec, the second response was greater than the first, reflecting the supernormal period, but impulse trains provoked hyperpolarization, as mentioned above, and reduced the amplitude of nerve action potentials. The results of this study show that the stimulus effect on nerves decreased at submaximal stimuli greater than 7-Hz, which reduced the amplitude of compound nerve action potentials. Therefore, averaging should be done at a stimulus frequency below 6-Hz.
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Affiliation(s)
- O Hasegawa
- Department of Neurology, Yokohama City University School of Medicine, Japan
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Matsumoto S, Hasegawa O, Kurita R, Komiyama A, Nara Y. [Repetitive discharges of proximal origin in a patient with carcinomatous sensory neuropathy]. No To Shinkei 1995; 47:769-771. [PMID: 7546922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Repetitive discharges of a motor unit potential were observed during ulnar nerve conduction studies in a patient with pathologically verified carcinomatous sensory neuropathy. The repetitive discharges in this patient had a latency similar to that of the F-wave latency. The first discharge was followed by discharges identical in configuration every 3 to 4 msec. These discharges responded to all of the suprathreshold stimuli, had a constant configuration, and exhibited jitter in their latency. When paired stimuli were applied, the second stimulus collided with the first discharge, leaving the afterdischarges behind at the previous position. Based on these electromyographic findings, the origin of these repetitive discharges is believed to have been the proximal part of a motor axon or a neighboring demyelinating lesion, since degenerative changes have been demonstrated in ventral roots as well as dorsal root ganglia in this disease.
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Affiliation(s)
- S Matsumoto
- Department of Neurology, Higashi Matsudo Municipal Hospital
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Hasegawa O, Komiyama A, Ohta S, Kurita R, Matsumoto M. [Stimulus effect and jumping of delayed potentials--investigation of human single nerve action potentials]. Rinsho Shinkeigaku 1995; 35:481-485. [PMID: 7664514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The jumping phenomenon is defined as an unexpected reduction in latency of evoked nerve responses with augmentation of stimulus intensity. This phenomenon may occur in the presence of segmental demyelination. To determine the severity of neuropathies, we recorded median nerve action potentials at the elbow of 60 patients of neuropathy by means of intraneural microneurography. Submaximal stimuli were delivered at the wrist or at one finger. In 53 of the 60 patients evaluated, delayed single nerve action potentials were recorded by submaximal stimuli that produced less than 10 microV compound nerve action potentials. In three delayed single unit potentials, latencies were shortened unexpectedly by several milliseconds when the intensity of stimulus was gradually increased. With the boundary stimulus intensity, we observed a small amplitude of the corresponding potentials at the delayed and the jumped latencies. Instead, jumping was suppressed with rapid repetitive stimuli. At the stimulus intensity sufficient to provoke jumping, we administered repetitive stimuli at 2Hz to 50Hz. At the rate of 20 to 30Hz, the corresponding potentials again returned to the delayed latencies. Rapid repetitive impulses may evoke cathodal hyperpolarization which raises the excitation threshold of the nerve. Thus, the stimulus effect can be decreased and jumping will be released. In addition, a diminution in amplitude and slight prolongation of the latency of each peak occurred in proportion to the increase in stimulus rate. However, paired stimuli with an interval of 4 to 13 msec was equivalent to a supernormal period and provoked the jumping of a single nerve unit. Conditioning stimuli may have increased the excitability of the corresponding fiber.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- O Hasegawa
- Department of Neurology, Yokohama City University School of Medicine
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Matsumoto M, Hasegawa O, Kurita R, Komiyama A, Nara Y. [Detection of subclinical sensory nerve dysfunction in amyotrophic lateral sclerosis--a microneurographic study]. No To Shinkei 1995; 47:345-8. [PMID: 7772401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In amyotrophic lateral sclerosis (ALS) sensory function has been considered to be normal on a clinical basis. There are, however, several pathologic reports indicating that peripheral sensory fibers are involved in ALS. To evaluate changes in sensory nerve function quantitatively, we measured compound nerve action potentials (CNAP) of the median nerve by means of intraneural microneurography (MNG) and compared the results between 16 patients with ALS, age-matched 13 patients with Parkinson disease (PD) and 13 healthy controls. A tungsten microelectrode with a tip diameter of 1 micron was inserted percutaneously into the median nerve trunk at the elbow. With supramaximal electric stimulation on the median nerve at the wrist, the largest CNAP was recorded. The configuration of the CNAP was similar among three groups, consisting of a large triphasic wave followed by small multiphaic waves. In ALS patients the peak to peak amplitude (Amp) of the triphasic wave was 189.0 +/- 49.8 microV (mean +/- SD), which was significantly smaller than 273.1 +/- 90.0 microV in PD patients and 325.4 +/- 81.0 microV in normal controls (p < 0.01). The maximal nerve conduction velocity (NCV) in ALS was also reduced when compared with that in PD patients and in normal controls (p < 0.05). The average reduction in Amp in ALS was 58% of that in normal controls, while decrease in NCV was less apparent than Amp and 96% of normal controls. The Amplitude of nerve action potentials is considered to represent the density of large myelinated fibers more than 7 microns around the microelectrode.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Matsumoto
- Department of Neurology, Yokohama City University School of Medicine, Japan
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Tobita M, Hasegawa O, Nagatomo H, Yamaguchi S, Kurita R. [Autotopagnosia ameliorated by looking at the image reflected in a mirror]. Rinsho Shinkeigaku 1995; 35:296-298. [PMID: 7542187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A 52-year-old right-handed man presented progressive dystonia and apraxia of his right hand of five years' duration. He also suffered from parkinsonian features such as rigidity or impaired postural reflexes. Serial investigation of brain MRI revealed progressive cerebral atrophy, which started in the left parietal lobe, and subsequently extended to both hemispheres. He was clinically diagnosed as corticobasal degeneration. He could not point at any part of his own body in response to verbal or visual commands. On the other hand, he could point at every part of the examiner's body or of the illustrated body image. Deep sensations and linguistic functions were not involved. This cognitive impairment was regarded as autotopagnosia. In contrast with inability to recognize any part of the own body in response to the commands, he could name every part of his body as soon as the examiner touched there. Moreover, his symptoms of autotopagnosia were ameliorated by looking at himself in a mirror; he could point at any part of his own body. Disconnection between primary proprioceptive sensory area and the center of body schema was thought to be the mechanism of autotopagnosia in this patient, because the impairment improved with the aid of visual or tactile informations. We speculated the lesion was the left parietal lobe.
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Affiliation(s)
- M Tobita
- Department of Neurology, Yokohama City University School of Medicine
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Hasegawa O, Ohta S, Komiyama A, Kurita R, Nara Y. [Intraneural topography of the median nerve at the elbow level--an analysis using intraneural neurography]. No To Shinkei 1995; 47:147-51. [PMID: 7669413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We examined intraneural topography of the median nerve at the elbow level by means of intraneural neurography in 38 individuals. A tungsten microelectrode was inserted into the median nerve trunk at the elbow where largest amplitude of the nerve action potential could be obtained with stimulations over median nerve trunk at the wrist. Each of six areas innervated by the nerve was stimulated supramaximally. The ratio of the amplitude of the nerve action potentials stimulated in each area to that stimulated over median nerve trunk at the wrist was arbitrary defined as territory index. the territory indices of six areas, i.e., thumb, index finger, middle finger, ring finger, little finger and thenar area, were 12%, 14%, 15%, 7%, 0% and 5%, respectively. Based on the investigation of permutations and combinations, the cutaneous fibers in the median nerve trunk at the elbow may be arranged in order of thumb-index-middle-ring fingers from the radial side, and the muscle fibers to the thenar muscles may be located at the palmar side to the index finger area. These results were in accordance with the previous reports obtained by near nerve recordings or anatomical analysis at the wrist. In 42% of the subjects a part of fibers in the median nerve were considered to innervate also little fingers, even though territory index was very small. This method has made it possible to estimate the intraneural topography of the median nerve at the elbow level and to detect Martin-Gruber anastomosis with a small number of sensory fibers.
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Affiliation(s)
- O Hasegawa
- Department of Neurology, Yokohama City University School of Medicine, Japan
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Kurita R, Hasegawa O, Komiyama A, Matsumoto S, Matsumoto M, Nara Y. Microneurographic evaluation of large myelinated fiber function of the peripheral nerve in neurologic disease. Pathophysiology 1994. [DOI: 10.1016/0928-4680(94)90642-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Hasegawa O, Komiyama A, Kurita R, Ota S, Matsumoto M. [Age-related changes in nerve action potentials of median nerve--an analysis using intraneural neurography]. Rinsho Shinkeigaku 1993; 33:1055-1058. [PMID: 8293605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Age-related decrease in peripheral nerve conduction velocity and the amplitude of sensory nerve action potentials is well established in humans. However, evaluation of the sensory nerve action potentials is subject to technical constraints because of its small size and variability of the values. To elucidate age-related differences, we determined the amplitude of median nerve action potentials in 52 healthy individuals aged 16 to 88 years by means of intraneural neurography. A tungsten microelectrode was inserted into the median nerve trunk at the elbow, and compound nerve action potentials evoked by supramaximal electrical stimulation were recorded. The action potentials consisted mainly of triphasic waves. Maximal conduction velocity (Y, m/sec) declined very mildly with age (X, year), showing the regression line of Y = 67.5 - 0.062X. The peak to peak amplitude of the potentials was 466.6 +/- 20.8 (SE) microV and declined gradually with a decrement of 13 microV per decade in the individuals under the age of 50 years. By contrast, in individuals above the age of 50 years, the amplitude (Y, microV) declined steeply, showing the regression line of Y = 977.1 - 9.86X (r = -0.75, p < 0.001) with age (X, year). A significant correlation was observed between amplitude of the sensory nerve action potentials obtained by the conventional technique and that obtained by the intraneural neurography. Nevertheless, an accelerated decrease was not found in the amplitude of the sensory nerve action potentials with age above 50, probably due to the variability of the values.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- O Hasegawa
- Department of Neurology, Yokohama City University School of Medicine
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