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A case of hereditary spherocytosis (HS) is reported. Cytogenetic study revealed a de nove minute deletion of chromosome 8. The critical portion which affected the expression of the HS phenotype appeared to be localized to 8p11.22→8p21.1. [ABSTRACT FROM AUTHOR]

A new glucose-6-phosphate dehydrogenase (G6PD) variant associated with chronic nonspherocytic hemolytic anemia was discovered. It was found in a 2-year-old male who had a hemolytic crisis after an upper respiratory tract infection. The enzyme activity of the variant was 8.4% of that of the normal enzyme. The enzymatic characteristics were slower than normal anodal electrophoretic mobility, low Km G6P, normal Km NADP, increased utilization of substrate analogues, high Ki NADPH, decreased heat stability, and an alkaline pH optimum. From these results, this was considered to be a new variant and was designated G6PD Sendagi. [ABSTRACT FROM AUTHOR]

Sub-gigahertz ferromagnetic resonance (FMR) is investigated in a magnetic tunnel junction (MTJ) with small anisotropy fields. Distinct FMR spectra down to 0.36 GHz are obtained by applying an external field that cancels out the anisotropy. A macrospin model simulation reveals that the difficulty in obtaining a smaller frequency excitation is not due to a magnetization inhomogeneity mainly attributed to domain creation but to a nonlinear thermal effect. The results indicate that anisotropy engineering through interfacial magnetic anisotropy together with voltage control will assist in realizing MTJs for low-frequency spin-torque devices. [ABSTRACT FROM AUTHOR]

The radio-frequency (RF) voltage amplification property of a tunnel magnetoresistance device driven by an RF external-magnetic-field-induced ferromagnetic resonance was studied. The proposed device consists of a magnetic tunnel junction and an electrically isolated coplanar waveguide. The input RF voltage applied to the waveguide can excite the resonant dynamics in the free layer magnetization, leading to the generation of an output RF voltage under a DC bias current. The dependences of the RF voltage gain on the static external magnetic field strength and angle were systematically investigated. The design principles for the enhancement of the gain factor are also discussed. [ABSTRACT FROM AUTHOR]

The influence of an electric field on an ultrathin FeCo film was investigated by x-ray absorption spectroscopy and magnetic circular dichroism. Measurements were done on sub-millimeter sized pillars, with partial fluorescence yield detection. Fe L2,3 absorption spectra revealed that partial oxidation of Fe occurred during the microfabrication. The oxidation state could be reversibly controlled by an electric field, which also induced variations of the dichroic signal. These results show that electrochemical phenomena may influence the magnetism at a ferromagnet/insulator interface. [ABSTRACT FROM AUTHOR]

We report on the spin-transfer magnetization switching properties of CoFe/Pd-based perpendicularly magnetized giant magnetoresistive cells over a wide current pulse duration time range. Analytic expressions without empirical parameters like attempt frequency are tested experimentally for the thermally assisted and precessional regimes. Good agreement with the experiment data is obtained using a common parameter set in both regimes, which leads to a comprehensive understanding of the switching properties including the origin of the attempt frequency. [ABSTRACT FROM AUTHOR]

We investigated spin-dependent quantum interference effects in Cr(001)/wedge Fe(001)/MgO(001)/Fe(001) magnetic tunnel junctions by dI/dV measurements. dI/dV intensities were mapped two-dimensionally as a function of applied voltage and Fe thickness, indicating a clear signature of quantum well (QW) states in the ultrathin Fe (001) electrode. However, resonant positions of QW states were systematically shifted by one monolayer when compared with the first-principles calculation results. X-ray absorption spectroscopy and magnetic circular dichroism measurements were also performed. While Fe oxide presence at Fe/MgO interface was ruled out, Fe/Cr intermixing could not be excluded. Hence, controlling the Fe/Cr interface may affect QW state. [ABSTRACT FROM AUTHOR]

Zinc coverage and the structures of Zn-exposed As-stabilized GaAs(001)-(2×4) and -c(4×4) surfaces have been studied using x-ray photoelectron spectroscopy and scanning tunneling microscopy in order to clarify the role of the Zn pre-exposure process in ZnSe growth on GaAs(001). Since Zn atoms stick on the GaAs-(2×4) surface even though their interaction is very weak, Zn may act as a balancer to form a neutral ZnSe/GaAs interface. Zn can also remove excess As atoms and make a “pure” (2×4) structure that is the only possible starting surface for low-defect ZnSe heteroexpitaxy on a GaAs(001) surface. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The mammalian genome contains two functional loci for the production of phosphoglycerate kinase, PGK-1, an X-linked gene expressed in all somatic cells, and PGK-2, an autosomal intron-less gene expressed exclusively in late spermatogenesis. A nucleotide substitution from guanine to thymine was recently found at position 473 of PGK-1 mRNA in PGK Shizuoka. The mutation was not found in the PGK-2 gene and might have occurred after separation of PGK-1 and PGK-2. [ABSTRACT FROM AUTHOR]