67 research outputs found
Three Phases in the 3D Abelian Higgs Model with Nonlocal Gauge Interactions
We study the phase structure of the 3D nonlocal compact U(1) lattice gauge
theory coupled with a Higgs field by means of Monte-Carlo simulations. The
nonlocal interactions among gauge variables are along the temporal direction
and mimic the effect of local coupling to massless particles. We found that in
contrast to the 3D local abelian Higgs model which has only one phase, the
present model exhibits the confinement, Higgs, and Coulomb phases separated by
three second-order transition lines emanating from a triple point. This result
is quite important for studies on electron fractionalization phenomena in
strongly-correlated electron systems. Implications to them are discussed
Diffusion-limited characteristics of mechanically induced currents in polypyrrole/Au-membrane composites
A mechanically induced current (MIC) in a polypyrrole/Au-coated membrane (PPy/Au-membrane) composite with various surface morphologies was investigated, and the electrolyte conditions were determined in an electrochemical cell. A MIC was induced on porous PPy/Au-membranes with a thin layer of PPy. Conversely, relatively small MICs were observed in non-highly porous films such as freestanding films and PPy/Au-membranes with thick PPy deposits. A MIC smaller by one order of magnitude was also observed in a Au-membrane without PPy. These results indicated that the MICs was due to a charging phenomenon in both the redox and the double layer capacitances. The MIC also varied with supporting electrolyte and their concentration. The MIC was strongly reduced in solutions with diluted electrolytes and with bulky cationic electrolytes, indicating that the number and the penetration speed of mobile ions limited the magnitude of the MIC. These characteristics indicated that the MIC was essentially a diffusion limited current. A two-electrode MIC cell was also configured to investigate a power generation film in a normal saline solution, which can possibly be utilized for biomedical applications
CP^1+U(1) Lattice Gauge Theory in Three Dimensions: Phase Structure, Spins, Gauge Bosons, and Instantons
In this paper we study a 3D lattice spin model of CP Schwinger-bosons
coupled with dynamical compact U(1) gauge bosons. The model contains two
parameters; the gauge coupling and the hopping parameter of CP bosons. At
large (weak) gauge couplings, the model reduces to the classical O(3) (O(4))
spin model with long-range and/or multi-spin interactions. It is also closely
related to the recently proposed "Ginzburg-Landau" theory for quantum phase
transitions of quantum spin systems on a 2D square lattice at zero
temperature. We numerically study the phase structure of the model by
calculating specific heat, spin correlations, instanton density, and
gauge-boson mass. The model has two phases separated by a critical line of
second-order phase transition; O(3) spin-ordered phase and spin-disordered
phase. The spin-ordered phase is the Higgs phase of U(1) gauge dynamics,
whereas the disordered phase is the confinement phase. We find a crossover in
the confinement phase which separates dense and dilute regions of instantons.
On the critical line, spin excitations are gapless, but the gauge-boson mass is
{\it nonvanishing}. This indicates that a confinement phase is realized on the
critical line. To confirm this point, we also study the noncompact version of
the model. A possible realization of a deconfinement phase on the criticality
is discussed for the CP+U(1) model with larger .Comment: Discussion of finite size scaling, O(4) spin correlation adde
Effects of heat treatment on human hair keratin film
5ArticleJOURNAL OF JAPANESE COSMETIC SCIENCE SOCIETY. 37(3):165-170 (2013)journal articl
Higgs mechanism and superconductivity in U(1) lattice gauge theory with dual gauge fields
We introduce a U(1) lattice gauge theory with dual gauge fields and study its
phase structure. This system is motivated by unconventional superconductors
like extended s-wave and d-wave superconductors in the strongly-correlated
electron systems. In this theory, the "Cooper-pair" field is put on links of a
cubic lattice due to strong on-site repulsion between electrons in contrast to
the ordinary s-wave Cooper-pair field on sites. This Cooper-pair field behaves
as a gauge field dual to the electromagnetic U(1) gauge field. By Monte Carlo
simulations we study this lattice gauge model and find a first-order phase
transition from the normal state to the Higgs (superconducting) state. Each
gauge field works as a Higgs field for the other gauge field. This mechanism
requires no scalar fields in contrast to the ordinary Higgs mechanism.Comment: 4 pages, 6 figure
Phase Structure of a 3D Nonlocal U(1) Gauge Theory: Deconfinement by Gapless Matter Fields
In this paper, we study a 3D compact U(1) lattice gauge theory with a variety
of nonlocal interactions that simulates the effects of gapless/gapful matter
fields. This theory is quite important to investigate the phase structures of
QED and strongly-correlated electron systems like the 2D quantum spin
models, the fractional quantum Hall effect, the t-J model of high-temperature
superconductivity. We restrict the nonlocal interactions among gauge variables
only to those along the temporal direction and adjust their coupling constants
optimally to simulate the isotropic nonlocal couplings of the original models.
We perform numerical studies of the model to find that, for a certain class of
power-decaying couplings, there appears a second-order phase transition to the
deconfinement phase as the gauge coupling constant is decreased. On the other
hand, for the exponentially-decaying coupling, there are no signals for
second-order phase transition. These results indicate the possibility that
introduction of sufficient number of massless matter fields destabilizes the
permanent confinement in the 3D compact U(1) pure gauge theory due to
instantons.Comment: The version to be published in Nucl.Phys.
State- and water repellency-controllable molecular glass of pillar[5]arenes with fluoroalkyl groups by guest vapors
Molecular glasses are low-molecular-weight organic compounds that are stable in the amorphous state at room temperature. Herein, we report a state- and water repellency-controllable molecular glass by n-alkane guest vapors. We observed that a macrocyclic host compound pillar[5]arene with the C₂F₅ fluoroalkyl groups changes from the crystalline to the amorphous state (molecular glass) by heating above its melting point and then cooling to room temperature. The pillar[5]arene molecular glass shows reversible transitions between amorphous and crystalline states by uptake and release of the n-alkane guest vapors, respectively. Furthermore, the n-alkane guest vapor-induced reversible changes in the water contact angle were also observed: water contact angles increased and then reverted back to the original state by the uptake and release of the n-alkane guest vapors, respectively, along with the changes in the chemical structure and roughness on the surface of the molecular glass. The water repellency of the molecular glass could be controlled by tuning the uptake ratio of the n-alkane guest vapor
FGF2 Has Distinct Molecular Functions from GDNF in the Mouse Germline Niche
Both glial cell line-derived neurotrophic factor (GDNF) and fibroblast growth factor 2 (FGF2) are bona fide self-renewal factors for spermatogonial stem cells, whereas retinoic acid (RA) induces spermatogonial differentiation. In this study, we investigated the functional differences between FGF2 and GDNF in the germline niche by providing these factors using a drug delivery system in vivo. Although both factors expanded the GFRA1+ subset of undifferentiated spermatogonia, the FGF2-expanded subset expressed RARG, which is indispensable for proper differentiation, 1.9-fold more frequently than the GDNF-expanded subset, demonstrating that FGF2 expands a differentiation-prone subset in the testis. Moreover, FGF2 acted on the germline niche to suppress RA metabolism and GDNF production, suggesting that FGF2 modifies germline niche functions to be more appropriate for spermatogonial differentiation. These results suggest that FGF2 contributes to induction of differentiation rather than maintenance of undifferentiated spermatogonia, indicating reconsideration of the role of FGF2 in the germline niche
キョウセン ヒテイケイテキ カルチノイド ノ 1セツジョレイ
Background. Thymic carcinoids are rare disease to account for 2-4% of anterior mediastinal tumors. So, the clinicopathologic characters are not known enough. Case. A 67 years old man was followed up old myocardial infarction, and he was taken chest CT scan for evaluate coronary artery. It revealed three anterior mediastinal tumors and we diagnosed thymoma by needle biopsy. We treated by neoadjuvant chemotherapy(CAMP therapy), but it was ineffective. We performed thoracoscopic thymothymomectomy, and the pathological diagnosis was thymic atypical carcinoid. He is free of clinically event recurrence one year and a half after treatment. Conclusions. When we found an anterior mediastinal tumor, and if the clinical course is usually different, we should consider the possibility of a thymic carcinoid
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