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Search Results: 1 - 10 of 67 matches for " Kiichi Arahata "
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Chromosome 4q;10q translocations; Comparison with different ethnic populations and FSHD patients
Tsuyoshi Matsumura, Kanako Goto, Gaku Yamanaka, Je Lee, Cheng Zhang, Yukiko K Hayashi, Kiichi Arahata
BMC Neurology , 2002, DOI: 10.1186/1471-2377-2-7
Abstract: To clarify the influence on the deletion of the repeats, we surveyed three different ethnic populations and FSHD patients using the BglII/BlnI dosage test.The frequency of translocation in 153 Japanese, 124 Korean, 114 Chinese healthy individuals and 56 Japanese 4q35-FSHD patients were 27.5%, 29.8%, 19.3%, and 32.1%, respectively. The ratio of '4 on 10' (trisomy and quatrosomy of chromosome 4) was higher than that of '10 on 4' (nullsomy and monosomy of chromosome 4) in all populations.The inter-chromosomal exchange was frequently observed in all four populations we examined, and no significant difference was observed between healthy and diseased groups.Facioscapulohumeral muscular dystrophy (FSHD) is a common form of muscular disorder with an autosomal dominant trait. FSHD is characterized by weakness and atrophy of facial, shoulder-girdle and humeral muscles, with occasional subsequent pelvic-girdle and lower limb involvement. More than 95% of patients with FSHD have a smaller (< 35 kb) EcoRI fragment on chromosome 4q35 detected by probe p13E-11 and are called 4q35-FSHD [1-3]. This EcoRI fragment in normal individuals contains tandem repeated 3.3-kb KpnI units (D4Z4) varying from 11 to 150 in number, while 4q35-FSHD patients showed less than ten units [2,3]. No responsible gene has been isolated within the FSHD gene region.Probe p13E-11 cross-hybridizes with chromosome 10q26, which contains highly homologous 3.3-kb KpnI repeated units. Since the BlnI restriction enzyme site exists exclusively within each unit derived from 10q26, but not in D4Z4 (an unit from 4q35), double enzyme digestion using EcoRI and BlnI can discriminate as 4q35 (BlnI-resistant) and 10q26 (BlnI-sensitive) units [4]. In a Dutch control population, subtelomeric translocations between chromosomes 4 and 10 were seen in about 20% of individuals [5-7]. Furthermore, somatic mosaicism was found in 40% of de novo FSHD families and 46% of these individuals had BlnI-resistant units on chromosome 10 [8].
Propagation of Second sound in a superfluid Fermi gas in the unitary limit
Emiko Arahata,Tetsuro Nikuni
Physics , 2009, DOI: 10.1103/PhysRevA.80.043613
Abstract: We study sound propagation in a uniform superfluid gas of Fermi atoms in the unitary limit. The existence of normal and superfluid components leads to appearance of two sound modes in the collisional regime, referred to as first and second sound. The second sound is of particular interest as it is a clear signal of a superfluid component. Using Landau's two-fluid hydrodynamic theory, we calculate hydrodynamic sound velocities and these weights in the density response function. The latter is used to calculate the response to a sudden modification of the external potential generating pulse propagation. The amplitude of a pulse which is proportional to the weight in the response function, is calculated the basis of the approach of Nozieres and Schmitt-Rink (NSR) for the BCS-BEC crossover. We show that, in a superfluid Fermi gas at unitarity, the second sound pulse is excited with an appreciate amplitude by density perturbations.
Damping of Condensate Oscillation of a Trapped Bose Gas in a One-Dimensional Optical Lattice at Finite Temperatures
Emiko Arahata,Tetsuro Nikuni
Physics , 2007, DOI: 10.1103/PhysRevA.77.033610
Abstract: We study damping of a dipole oscillation in a Bose-Condensed gas in a combined cigar-shaped harmonic trap and one-dimensional (1D) optical lattice potential at finite temperatures. In order to include the effect of thermal excitations in the radial direction, we derive a quasi-1D model of the Gross-Pitaeavskii equation and the Bogoliubov equations. We use the Popov approximation to calculate the temperature dependence of the condensate fraction with varying lattice depth. We then calculate the Landau damping rate of a dipole oscillation as a function of the lattice depth and temperature. The damping rate increases with increasing lattice depth, which is consistent with experimental observations. The magnitude of the damping rate is in reasonable agreement with experimental data. We also find that the damping rate has a strong temperature dependence, showing a sharp increase with increasing temperature. Finally, we emphasize the importance of the radial thermal excitations in both equilibrium properties and the Landau damping.
Theory of the Two-Particle Emission from Superfluid Fermi Gases in the BCS-BEC Crossover
Emiko Arahata,Tetsuro Nikuni
Physics , 2013, DOI: 10.1103/PhysRevA.90.043601
Abstract: We present a theory of the emission of fermion pairs from a superfluid Fermi gas induced by a photon absorption. In the solid state physics, this type of process is called double photo-emission (DPE). The spectrum of the induced two-particle current (or DPE current) provides a direct insight into the pair-correlation of condensate fermion pairs. We develop a general formalism for two-particle current induced by DPE by treating the coupling of two Fermi gases with the time-dependent perturbation theory. This formalism is used to calculate energy distributions of DPE current from the superfluid Fermi gas in the BCS-BEC crossover at T=0. We show that the DPE current has distinct contributions of the condensed pair components and uncorrelated pair states. We also calculate the angular dependence of DPE current in the BCS-BEC crossover. The DPE current of the tightly-bound molecules in the BEC regime is found to be quite deferent from that of the weakly-bound Cooper pairs.
DC conductivity in an s-wave superconducting single vortex system
Emiko Arahata,Yusuke Kato
Physics , 2013, DOI: 10.1007/s10909-013-0992-5
Abstract: We study dynamics of a two-dimensional s-wave superconductor in the presence of a moving single vortex. Our analysis is based on the quasiclassical theory including the Hall term, generalized by Kita[T. Kita, PRB, 64, 054503 (2001)]. We numerically calculate the linear response of a moving single vortex driven by a dc external current in a self-consistent way, in the sense that Dyson equation, gap equation, Maxwell equations and generalized quasiclassical equation are solved simultaneously. We obtain Hall conductivity induced by vortex motion using the generalized quasiclassical equation, while we confirm that it vanishes in the conventional quasiclassical equation.
Bose-Condensed Gases in a 1D Optical Lattice at Finite Temperatures
E. Arahata,T. Nikuni
Physics , 2006, DOI: 10.1007/s10909-007-9396-8
Abstract: We study equilibrium properties of Bose-Condensed gases in a one-dimensional (1D) optical lattice at finite temperatures. We assume that an additional harmonic confinement is highly anisotropic, in which the confinement in the radial directions is much tighter than in the axial direction. We derive a quasi-1D model of the Gross-Pitaeavkill equation and the Bogoliubov equations, and numerically solve these equations to obtain the condensate fraction as a function of the temperature.
Critical Velocity in a Bose Gas in a Moving Optical Lattice at Finite Temperatures
Emiko Arahata,Tetsuro Nikuni
Physics , 2009, DOI: 10.1103/PhysRevA.79.063606
Abstract: We study the critical velocity of a Bose-condensed gas in a moving one-dimensional (1D) optical lattice potential at finite temperatures. Solving the Gross-Pitaeavskii equation and the Bogoliubov equations, within the Popov approximation, we calculate the Bogoliubov excitations with varying lattice velocity. From the condition of the negative excitation energy, we determine the critical velocity as a function of the lattice depth and the temperature. We find that the critical velocity decreases rapidly with increasing the temperature; this result is consistent with the experimental observations. Moreover, the critical velocity shows a rapid decrease with increasing lattice depth. This tendency is much more significant than in the previous works ignoring the effect of thermal excitations in the radial direction.
Kiichi Amimoto
Acta Crystallographica Section E , 2011, DOI: 10.1107/s160053681103772x
Abstract: The title compound, C18H30O2, was prepared by Friedel–Crafts alkylation of 1,4-dimethoxybenzene with 2-methyl-2-butanol. The complete molecule is generated by the application of a crystallographic centre of inversion. The two methoxy groups are oriented in the same plane of the aromatic ring [C—C—O—C torsion angle = 9.14 (16)°]. While one methyl group of the tert-pentyl substituent is coplanar with the benzene ring [C—C—C—C = 0.45 (15)°] and lies towards the less-hindered H atom, the other methyl and ethyl groups are directed to either side of the benzene ring [C—C—C—C torsion angles = 118.78 (12) and 59.11 (14)°, respectively]. In the crystal, the hydrophobic molecules pack to form a brick-wall-like architecture.
Myoclonus-like involuntary movements under subarachnoid block completely subsided after midazolam administration in a patient undergoing cesarean section: a case report
Kiichi Hirota
PeerJ , 2015, DOI: 10.7287/peerj.preprints.101v1
Abstract: Involuntary movement during and after neuraxial anesthesia, such as spinal and epidural anesthesia, is rarely observed. In this report, we describe a case of myoclonus-like involuntary movement of the upper extremities in a patient undergoing a planned repeat cesarean section under spinal anesthesia with bupivacaine that completely subsided after 2mg midazolam administration. The myoclonus-like movement never recurred or caused any apparent neurological side effects. No abnormal sensation or spontaneous pain of the upper extremities was observed. The patient was discharged on foot on post-operative day 3.
Successful perioperative airway management in a patient with angiomatous macroglossia for laser ablation under general anesthesia
Kiichi Hirota
PeerJ , 2015, DOI: 10.7287/peerj.preprints.99v1
Abstract: Macroglossia is defined as an abnormal enlargement of the tongue that predominantly affects pediatric patients and is not frequent in adult patients. Hypothyroidism and hyperpituitarism may cause macroglossia in adults. In addition, infiltration of the tongue by abnormal tissues, including angiomatous and lymphatic malformations and amyloidosis, is a major cause of macroglossia, particularly in adults. Here we describe the case of a 63-year-old male patient with massive macroglossia due to tongue hemangioma who underwent laser ablation under general anesthesia. Elaborate preanesthetic anatomical and functional airway evaluation facilitated successful airway management in this patient, even in the presence of massive macroglossia.
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