Roles of Fukutin, the Gene Responsible for Fukuyama-Type Congenital Muscular Dystrophy, in Neurons: Possible Involvement in Synaptic Function and Neuronal Migration

Fukutin is a gene responsible for Fukuyama-type congenital muscular dystrophy (FCMD), accompanying ocular and brain malformations represented by cobblestone lissencephaly. Fukutin is related to basement membrane formation via the glycosylation of α-dystoglycan (α-DG), and astrocytes play a crucial role in the pathogenesis of the brain lesion. On the other hand, its precise function in neurons is unknown. In this experiment, the roles of fukutin in mature and immature neurons were examined using brains from control subjects and FCMD patients and cultured neuronal cell lines. In quantitative PCR, the expression level of fukutin looked different depending on the region of the brain examined. A similar tendency in DG expression appears to indicate a relation between fukutin and α-DG in mature neurons. An increase of DG mRNA and core α-DG in the FCMD cerebrum also supports the relation. In immunohistochemistry, dot-like positive reactions for VIA4-1, one of the antibodies detecting the glycosylated α-DG, in Purkinje cells suggest that fukutin is related to at least a post-synaptic function via the glycosylation of α-DG. As for immature neurons, VIA4-1 was predominantly positive in cells before and during migration with expression of fukutin, which suggest a participation of fukutin in neuronal migration via the glycosylation of α-DG. Moreover, fukutin may prevent neuronal differentiation, because its expression was significantly lower in the adult cerebrum and in differentiated cultured cells. A knockdown of fukutin was considered to induce differentiation in cultured cells. Fukutin seems to be necessary to keep migrating neurons immature during migration, and also to support migration via α-DG

Predominant Dissemination of PVL-Negative CC89 MRSA with SCCmec Type II in Children with Impetigo in Japan

Background. The ratio of CA-MRSA in children with impetigo has been increasing in Japan. Methods. Antimicrobial susceptibilities of 136 S. aureus isolates from children with impetigo were studied. Furthermore, molecular epidemiological analysis and virulence gene analysis were performed. Results. Of the 136 S. aureus isolates, 122 (89.7%) were MSSA and 14 (10.3%) were MRSA. Of the 14 MRSA strains, 11 belonged to CC89 (ST89, ST91, and ST2117) and carried diverse types of SCCmec: type II (IIb: 3 strains; unknown subtype: 4 strains), type IVa (2 strains), and unknown type (2 strains). The remaining three strains exhibited CC8 (ST-8)-SCCmec type VIa, CC121 (ST121)-SCCmec type V, and CC5 (ST5)-nontypeable SCCmec element, respectively. None were lukS-PV-lukF-PV gene positive. Gentamicin- and clarithromycin-resistant strains were frequently found in both MRSA and MSSA. Conclusions. PVL-negative CC89-SCCmec type II strains are the most predominant strains among the CA-MRSA strains circulating in the community in Japan

Charge Ordering in the One-Dimensional Extended Hubbard Model: Implication to the TMTTF Family of Organic Conductors

We study the charge ordering (CO) in the one-dimensional (1D) extended Hubbard model at quarter filling where the nearest-neighbor Coulomb repulsion and dimerization in the hopping parameters are included. Using the cluster mean-field approximation to take into account the effect of quantum fluctuations, we determine the CO phase boundary of the model in the parameter space at T=0 K. We thus find that the dimerization suppresses the stability of the CO phase strongly, and in consequence, the realistic parameter values for quasi-1D organic materials such as (TMTTF)$_2$PF$_6$ are outside the region of CO. We suggest that the long-range Coulomb interaction between the chains should persist to stabilize the CO phase.Comment: 5 pages, 4 eps figures, to appear in 15 Nov. 2001 issue of PR

Fictitious Magnetic Resonance by Quasi-Electrostatic Field

We propose a new kind of spin manipulation method using a {\it fictitious} magnetic field generated by a quasi-electrostatic field. The method can be applicable to every atom with electron spins and has distinct advantages of small photon scattering rate and local addressability. By using a $\rm{CO_2}$ laser as a quasi-electrostatic field, we have experimentally demonstrated the proposed method by observing the Rabi-oscillation of the ground state hyperfine spin F=1 of the cold $\rm{^{87}Rb}$ atoms and the Bose-Einstein condensate.Comment: 5 pages, 5 figure

Temperature Dependence of Spin Correlation and Charge Dynamics in the Stripe Phase of High-T_c Superconductors

We examine the temperature dependence of the electronic states in the stripe phase of high-Tc cuprates by using the t-J model with a potential that stabilizes vertical charge stripes. Charge and spin-correlation functions and optical conductivity are calculated by using finite-temperature Lanczos method. At zero temperature, the antiferromagnetic correlation between a spin in a charge stripe and that in a spin domain adjacent to the stripe is weak, since the charge stripe and the spin domain are almost separated. With increasing temperature, the correlation increases and then decreases toward high temperature. This is in contrast to other correlations that decrease monotonically. From the examination of the charge dynamics, we find that this anomalous temperature dependence of the correlation is the consequence of a crossover from one-dimensional electronic states to two-dimensional ones.Comment: 7 pages in two-column format, 6 figures, to be published in Phys. Rev.

Effect of Stripes on Electronic States in Underdoped La_{2-x}Sr_xCuO_4

We investigate the electronic states of underdoped La_{2-x}Sr_xCuO_4 (LSCO) by using a microscopic model, i.e., t-t'-t''-J model, containing vertical charge stripes. The numerically exact diagonalization calculation on small clusters shows the consistent explanation of the physical properties in the angle-resolved photoemission, neutron magnetic scattering and optical conductivity experiments such as the antiphase domain and quasi-one-dimensional charge transport. The pair correlation function of the d-channel is suppressed by the stripes. These results demonstrate a crucial role of the stripes in LSCOComment: 4 pages, 4 EPS figures, revised version, to appear in Phys. Rev. Lett. Vol.82, No.25, 199

Development and operational experience of magnetic horn system for T2K experiment

A magnetic horn system to be operated at a pulsed current of 320 kA and to survive high-power proton beam operation at 750 kW was developed for the T2K experiment. The first set of T2K magnetic horns was operated for over 12 million pulses during the four years of operation from 2010 to 2013, under a maximum beam power of 230 kW, and $6.63\times10^{20}$ protons were exposed to the production target. No significant damage was observed throughout this period. This successful operation of the T2K magnetic horns led to the discovery of the $\nu_{\mu}\rightarrow\nu_e$ oscillation phenomenon in 2013 by the T2K experiment. In this paper, details of the design, construction, and operation experience of the T2K magnetic horns are described.Comment: 22 pages, 40 figures, also submitted to Nuclear Instrument and Methods in Physics Research,

Thermodynamics and Crossover Phenomena in the Correlation Lengths of the One-Dimensional t-J Model

We investigate the thermodynamics of the one-dimensional t-J model using transfer matrix renormalization group (TMRG) algorithms and present results for quantities like particle number, specific heat, spin susceptibility and compressibility. Based on these results we confirm a phase diagram consisting of a Tomonaga-Luttinger liquid (TLL) phase for small J/t and a phase separated state for J/t large. Close to phase separation we find a spin-gap (Luther-Emery) phase at low densities consistent with predictions by other studies. At the supersymmetric point we compare our results with exact results from the Bethe ansatz and find excellent agreement. In particular we focus on the calculation of correlation lengths and static correlation functions and study the crossover from the non-universal high T lattice into the quantum critical regime. At the supersymmetric point we compare in detail with predictions by conformal field theory (CFT) and TLL theory and show the importance of logarithmic corrections.Comment: 14 pages, 20 figure