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Magnetoconductance (MC) at low temperature was measured to investigate spin-related transport affected by spin-orbit interaction (SOI) in III-VI compound $n$-type GaSe thin films. Results reveal that MC shows weak antilocalization (WAL). Its temperature and gate voltage dependences reveal that the dominant spin relaxation is governed by the D'yakonov-Perel' mechanism associated with the Rashba SOI. The estimated Rashba SOI strength in GaSe is much stronger than that of III-V compound GaAs quantum wells, although the energy gap and spin split-off band in GaSe closely resemble those in GaAs. The angle dependence of WAL amplitude in the in-plane magnetic field direction is almost isotropic. This isotropy indicates that the strength of the Dresselhaus SOI is negligible compared with the Rashba SOI strength. The SOI effect in $n$-GaSe thin films differs greatly from those of III-V compound semiconductors and transition-metal dichalcogenides.

Serotype 23B Streptococcus pneumoniae was isolated from a 67-year-old Japanese patient with meningitis. This isolate was susceptible to penicillin G, while genotyped as gPISP with a mutation in a penicillin-binding motif in PBP2b. The 23B isolate was assigned to ST11996 that is related to CC439, a dominant group among serotype 23B.

Serotype 23B Streptococcus pneumoniae was isolated from a 67-year-old Japanese patient with meningitis. This isolate was susceptible to penicillin G, while genotyped as gPISP with a mutation in a penicillin-binding motif in PBP2b. The 23B isolate was assigned to ST11996 that is related to CC439, a dominant group among serotype 23B.

We implement time-resolved Kerr microscopy (TRKM) system with ∼ 1 μ m spatial resolution for observation of coupled electron–nuclear spin dynamics such as dynamic nuclear polarization (DNP) in a local area of the laser spot. From TRKM measurements, Larmor precession of electron spins injected by right ( σ + ) or left ( σ − ) circular polarized pump pulse is detected. The difference of the precession frequencies between σ + and σ − pumping corresponds to the polarization-dependent nuclear magnetic field caused by DNP. This indicates that we successfully detect coupled electron–nuclear spin dynamics in a local area of the laser spot size of ∼ 1.5 × 1.5 μ m 2 . Furthermore, we show the pump and probe power dependences of DNP in high optical intensity region. All-optical NMR is also demonstrated at arbitrary frequencies by controlling acousto-optical modulator.

We investigate the photoluminescence (PL) polarization of millimeter-scale GaSe films with 100 nm and 150 ?m thicknesses by excitation with linearly and circularly polarized light. Although free exciton emission predominates at 140 K, multiple peaks appear at 30 K owing to the recombination with impurity and/or localized states. Despite the circularly and linearly polarized excitations, the 100-nm-thick GaSe film constantly shows linear polarization in both band-edge and impurity/localized PLs. By rotating the sample geometry, the observed linear polarization is also rotated. This indicates that linear polarization is sensitive to the sample geometry and originates from the optical waveguide effect.

Electron spin dynamics in strained In 0.1 Ga 0.9 As/Al 0.4 Ga 0.6 As quantum wells (QWs) on (1 0 0) and (1 1 0) -oriented substrates are investigated by time-resolved Faraday rotation. We find that the spin relaxation time in (1 1 0) QWs is 6 times longer than that in (1 0 0) QWs at low temperatures, which is strongly reduced by applying magnetic fields. The sign of g -factor is found positive and its magnitude decreases with increasing well width, in the well width range investigated here.

Gate-voltage dependences of nuclear spin relaxation and decoherence times in a Schottky-gated n-GaAs/AlGaAs (110) quantum well (QW) are investigated by time-resolved Kerr-rotation measurements combined with pulsed-rf nuclear magnetic resonance (NMR). We show that the nuclear spin relaxation and decoherence times decrease with decreasing electron density, indicating that the hyperfine interaction is enhanced as the electronic states becomes localized in an impurity-doped QW.

We investigated the doping concentration (ND) dependence of the extrinsic spin Hall effect (SHE) in n-doped GaAs with ND raging from 3×1016 cm−3 to 5×1017 cm−3. By using scanning Kerr microscopy (SKM) measurements, we observed the Kerr rotation signal due to the spin accumulation near the channel edges in all the samples with different ND. Moreover, the position and in-plane magnetic field dependence of the Kerr rotation signal are found to vary with ND. We analyzed the ND dependence of the spin Hall conductivity by taking account of the ND-dependent spin lifetime based on the typical drift-diffusion model.

Understanding the effect of the interface on electrical spin injection is of great importance for the development of semiconductor spintronics. Fe/GaAs(001) is one of the leading systems for exploring these effects due to the small lattice mismatch. We report on the correlation between the experimentally observed Fe/GaAs(001) interface with the spin-transport properties. Using high-angle annular dark-field scanning transmission electron microscopy, we observe a predominantly abrupt interface with some regions of partial mixing also observed in the same film. We report that reproducible behavior with no bias-dependent polarization inversion was achieved for three-terminal devices. Using ab initio calculations of the experimentally observed interfaces, we show that the contribution to the transport from minority carriers is strongly dependent on the interface structure.

We investigated the quadrupolar splitting dependence of the nuclear spin coherence time in an n‐(110)GaAs/AlGaAs quantum well by time‐resolved Kerr‐rotation measurements combined with pulsed‐rf nuclear magnetic resonance. In GaAs, all the constituent nuclei have quadrupole moment. Therefore the quadrupolar splitting is induced by electric field gradient, which can be controlled by varying strain. We found that the nuclear spin coherence time is extended as the quadrupolar splitting increases by applying the strain. This suggests that the influences of the other transitions are suppressed with increase of the quadrupolar splitting.

We demonstrate manipulation of nuclear spin coherence in a GaAs/AlGaAs quantum well by optically detected nuclear magnetic resonance (NMR). A phase shift of the Larmor precession of photoexcited electron spins is detected to read out the hyperfine-coupled nuclear spin polarization. Multipulse NMR sequences are generated to control the population and examine the phase coherence in quadrupolar-split spin-3/2 75 As nuclei. The phase coherence among the multilevel nuclear spin states is addressed by application of pulse sequences that are used in quantum gate operations.

Gate control of dynamic nuclear polarization under optical orientation is demonstrated in a Schottky-gated $n\mathrm{\text{\ensuremath{-}}}\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}$ (110) quantum well by time-resolved Kerr rotation measurements. Spin relaxation of electrons due to mechanisms other than the hyperfine interaction is effectively suppressed as the donor induced background electron density is reduced from metallic to insulating regimes. Subsequent accumulation of photoexcited electron spins dramatically enhances dynamic nuclear polarization at low magnetic field, allowing us to tune nuclear spin polarization by external gate voltages.

In this work, we investigated the well width dependence of dynamic nuclear polarization in n‐GaAs/Al0.3Ga0.7As (110) quantum wells. We prepared a set of samples with different well width and thus different g‐factor, and measured the degree of dynamic nuclear polarization in these samples by time‐resolved Faraday rotation measurements. Our calculation, considering simply the projection of time‐averaged electron spins along the external magnetic field, reproduced overall shapes of the nuclear fields as a function of anisotropy of g‐factor.

[1] The effect of nontidal ocean mass loading is investigated as a possible cause for the seasonal variability observed in the vertical components of the GPS-derived site coordinates of tropical Pacific islands. The nontidal ocean mass origin sea level changes (MOSLCs) are estimated by subtracting the steric height changes observed at buoys from the net sea level changes measured by satellite altimetry. Assuming a linear relationship between the MOSLCs at the closest buoys and the GPS vertical movements, the coherences and the admittances are estimated. We found evidence that the vertical movements are caused by the loading effect at three out of four sites. The occasional deviations between the vertical movements and predicted loading deformations are presumably due to the invalidity of the assumption of a linear relationship between the MOSLCs and the loading deformation and/or of the mean temperature-salinity relationship used in estimating steric heights in the corresponding periods.

We investigated the dynamics of a coupled electron-nuclear spin system in a GaAs/AlGaAs (110) quantum well by time-resolved Faraday rotation measurements. Photoexcited electron spins with long coherence time ${(T}_{2}^{*}=6\mathrm{ns})$ are strongly subject to a nuclear field as well as polarizing the nuclei. A hysteretic behavior was observed in the magnetic-field dependence of the nuclear polarization under optical orientation. Our quantitative analysis based on self-consistent calculations reproduced the experimental observation of the bistable configurations of dynamic nuclear polarization.

The purpose of this study was to develop a new, simple, and more efficient method for estimating joint fluid volume in the knee of experimental animals by measuring endogenous calcium concentration, which is maintained rigidly at a constant level in the body fluid.Calcium concentrations in the plasma and joint cavity lavage were colorimetrically measured in normal and papain-induced arthritic rabbits. The joint fluid volume was estimated by dividing the total calcium concentration in the joint cavity lavage (microg/joint) by calcium concentration in the plasma (microg/ml). To confirm the relevancy of this method, radioactivity in the plasma and joint cavity lavage was determined after intravenously injecting 3H2O. The correlation between the joint fluid volumes obtained from the two different methods was examined to evaluate the validity of the method involving measurement of the calcium concentration. Results The joint fluid volumes of normal rabbits were estimated at 401 micro/joint and that in the arthritic rabbits at 680 microl/joint by measuring calcium concentration, respectively. These values were not significantly different from those estimated by radioactivity in the plasma and joint cavity lavage (normal: 425 microl/joint, arthritis: 761 microl/joint). A statistically significant correlation was observed between the values obtained from the two methods (r = 0.985). This method is considered useful for the evaluation of therapeutic medicine for arthritis or for hydrarthrosis research using experimental animal models.

Transjugular intrahepatic portosystemic shunt (TIPS) using an 8-mm Gianturco-Rösch Z stent was performed in 10 patients with liver cirrhosis admitted due to ruptured gastroesophageal varices. The treatment was successful in 9 patients, and the portal pressure decreased form 25 mmHg to 17 mmHg immediately after TIPS and to 15 mmHg 2 weeks after TIPS. The patency of the shunt was maintained adequately in the patients examined 3 months after TIPS. Endoscopy 1 month after TIPS showed improvements in the gastroesophageal varices in all patients. Hemobilia and intraperitoneal bleeding were observed in 1 patient each during procedure. Transient jaundice was observed in 2 and increase in the blood ammonia level were noted in 3 (one of whom had hepatic encephalopathy) postoperatively. All these complications could be treated easily. TIPS which brings about an immediate marked reduction in the portal pressure appears to be promising as a new treatment for portal hypertension.

We investigated the magnetic field dependence of quadrupolar splitting and phase relaxation time of nuclear spins in an n-GaAs/AlGaAs (110) quantum well (QW) by optically detected nuclear magnetic resonance (NMR). The NMR spectra show large quadrupolar splitting induced by an internal field gradient in the QW epilayer. At lower magnetic fields, the quadrupolar splitting become much enhanced, resulting in the appearance of the second order magnetic field dependence of the quadrupole interaction in the NMR spectra. It is also shown that the intrinsic coherence time and the effective coherence time for resonant transitions become shorter as a result that the energy splitting between the two levels becomes small and incoherent transition is occurred by irradiation of an rf magnetic field.

We investigated the gate voltage dependence of the nuclear spin relaxation in a Schottky-gated n-GaAs/AlGaAs (110) quantum well by the time-resolved Kerr rotation measurement combined with the nuclear magnetic resonance technique. The Fermi contact hyperfine interaction is enhanced by decreasing the background electron density, as the electrons become localized at impurity site. The energy relaxation time T1 and the decay time of the Rabi oscillation T2Rabi can be controlled by more than a factor of 10 and a factor of ∼2, respectively.

Spin-dependent intersubband excitonic interactions have been investigated in GaAs/AlGaAs quantum wells by two-color pump and probe spectroscopy. We generated spin-polarized electrons in the lowest subband by resonant excitation of the heavy-hole exciton (E1-HH1) and observed polarization-dependent broadening of the second-subband exciton resonance (E2-HH2 and E2-LH1). The exchange interaction between the first and the second-subband excitons is found to play a crucial role in polarization-dependent spectral modulation as well as spin-independent Coulomb screening.

The unexpected "0.7" plateau of conductance quantisation is usually observed for ballistic one-dimensional devices. In this work we study a quasi-ballistic quantum wire, for which the disorder induced backscattering reduces the conductance quantisation steps. We find that the transmission probability resonances coexist with the anomalous plateau. The studies of these resonances as a function of the in-plane magnetic field and electron density point to the presence of spin polarisation at low carrier concentrations and constitute a method for the determination of the effective g-factor suitable for disordered quantum wires., 4 pages, 6 figures

Anisotropic spin dynamics of two-dimensional electrons in strained n-InGaAs∕AlGaAs (110) quantum wells (QWs) is investigated by a time-resolved Faraday rotation technique. Strong anisotropy of the relaxation time for the electron spins in parallel (τ‖) and perpendicular (τ⊥) to the QWs is observed (τ⊥∕τ‖∼60) at 150 K as a result of the enhanced D'yakonov–Perel' (DP) spin relaxation mechanism. At 5 K, an anisotropic feature of the spin relaxation time is also observed in the presence of in-plane magnetic field, suggesting that the DP mechanism is effective for low-temperature spin relaxation.

Changes in natural killer (NK) cell, antibody-dependent cell-mediated cytotoxicity (ADCC) and interferon activities after administration of Nocardia rubra cell wall skeleton (N-CWS) to a group of subjects with high risk of lung cancer (retired workers of the Okunojima poison gas factory) were studied. No difference in NK cell activity against K-562 derived from chronic myelogeneous leukemia was observed among normal controls, non N-CWS-injected workers and N-CWS-injected workers. None of the normals or N-CWS-injected retired workers showed low NK cell activity (less than 10% cytotoxicity), but among the non N-CWS-injected workers 6.3% showed reduced activity. Following injection of N-CWS, NK cell activity against K-562 and T-24 derived from bladder cancer was significantly elevated by the second week and then gradually reverted to the preinjection level. When a second injection was administered at the twelfth week, a similar elevation was noted. Further, a significant increase was noted in ADCC activity two weeks after N-CWS injection. There was a significant elevation of interferon at the second week after N-CWS injection. It was considered that N-CWS affects the NK cell activity enhancement by serum interferon.

Peripheral blood lymphocyte subsets were determined in former workers of the Okunojima Poison Gas Factory (poison gas workers) having a high incidence of lung cancer, and the effect of administration of Nocardia rubra cell wall skeleton (N-CWS) was studied. In poison gas workers not receiving N-CWS, both the percentage and absolute number of Leu-2a+ cells were significantly increased as compared with normal controls, while both the percentage and absolute number of Leu-7+ cells as well as the Leu-3a/Leu-2a ratio were significantly decreased. In poison gas workers receiving N-CWS, the percentage of Leu-2a+ cells was significantly decreased when compared with poison gas workers not receiving N-CWS, while the percentage of Leu-1+ cells and both the percentage and absolute number of Leu-7+ cells as well as the Leu-3a/Leu-2a ratio were significantly increased. When N-CWS was administered to poison gas workers, the percentage of Leu-2a+ cells significantly decreased, with a minimum two weeks after administration, while the percentage of Leu-3a+ and the Leu-3a/Leu-2a ratio significantly increased and the percentages of Leu-1+ and Leu-7+ cells also increased. Furthermore, the absolute number of Leu-3a+ cells increased markedly with a peak two weeks after administration. The absolute numbers of both Leu-1+ cells and Leu-7+ cells as well as total lymphocytes also significantly increased, but that of Leu-2a+ cells showed hardly any change. It is considered that a single administration of N-CWS transiently corrects the abnormality of lymphocyte subsets, and that repeated administration of N-CWS once every three months may maintain the lymphocyte subsets of poison gas workers at normal levels.

Phytohemagglutinin (PHA)-induced interleukin 2 (IL-2) production and lymphocyte proliferation were measured in former workers of the Okunojima Poison Gas Factory (poison gas workers), who have a high incidence of lung cancer, and the efficacy of administration of Nocardia rubra cell wall skeleton (N-CWS) was studied. In comparison with normal controls and poison gas workers receiving N-CWS, lymphocyte proliferation in poison gas workers not receiving N-CWS showed a significant decrease, while IL-2 production showed a slight though not statistically significant decrease. When N-CWS was administered to poison gas workers, IL-2 production and lymphocyte proliferation were significantly elevated, with a peak two weeks after administration. N-CWS, by elevating IL-2 production of lymphocytes, is considered to have improved the depression of lymphocyte proliferation.