Search

It is well known that the enhancement of halo neutron removal cross sections in neutron halo nuclei. This is one of the evidence for the neutron halo structure. Because the valence neutron of the isomeric state in 16 N is considered to be mainly occupying in the s-orbital, we studied the nuclear structure of 16 N as a candidate for neutron halo nucleus. In this study, we measured one-neutron removal cross sections σ - 1 n using secondary beams of 16 N with a mixture of ground and isomeric states. We used two types of primary beams, 15 N and 18 O, to produce 16 N beams with different isomeric ratios (8.7, 24.2a 16 N beam with a large isomeric ratio is large compared to that obtained with another beam with a small isomeric state. This result suggests that the 16 N isomeric state is considered to have a neutron-halo-like structure. [ABSTRACT FROM AUTHOR]

We have investigated the role of the m/n = 2/1 neoclassical tearing mode (NTM) for suppression of the sawtooth collapse in JT-60U from the viewpoint of the anomalous transport of the current diffusion, namely flux pumping. In the stabilization experiments of m/n = 2/1 NTMs by electron cyclotron current drive of JT-60U, it has been clarified that the sawtooth collapses occur during or after the stabilization of m/n = 2/1 NTMs. It is also confirmed that the minimum safety factor, qmin, is nearly unity before and after the stabilization of an m/n = 2/1 NTM. While the flux pumping by ELM-NTM coupling was reported in DIII-D, the suppression of the sawtooth collapse is observed without ELMs in this study. On the other hand, it is observed that the sawtooth precursor appears during the stabilization of the m/n = 2/1 NTM accompanying the disappearance of the fluctuation of the n = 1 helical core (HC), which is induced by the m/n = 2/1 NTM. In addition, the modulation of the toroidal rotation velocity having the frequency of the n = 1 HC is observed in the core region. Because the helical flow with HCs is a possible source of the dynamo loop voltage in tokamaks, these observations suggest that the suppression of the sawtooth collapse in JT-60U is realized by the dynamo loop voltage due to the n = 1 HC induced by the m/n = 2/1 NTM. Our result indicates that n = 1 HCs induced by other MHD modes also may induce anomalous current transport in tokamaks. [ABSTRACT FROM AUTHOR]

Migration of Baylisascaris potosis larvae in different mouse strains were compared, and infectivity of the persisting larvae in mice tissues were investigated. Five strains of mice, BALB/c, C57BL/6, AKR, B10.BR, and ICR were inoculated with 1,000 B. potosis eggs/mouse, and necropsied at week 13 post inoculation (PI). The other uninfected ICR mice (secondary host) were inoculated with 43 larvae/ mouse recovered from mice at week 13 PI with eggs, and necropsied at day 21 PI. Larvae in organs or tissues were counted at necropsy. One AKR mouse showed torticollis and circling at day 56 PI. At necropsy at week 13 PI, larvae were recovered from all mice. A mean total larvae recovered were 124.1 (n=40). Majority of larvae were found in the carcass (mean 113.9) and some in the viscera (mean 9.9). Zero to 1 larva were found in the brain or eyes of some mice. There were no differences among the mouse strains in the number of larvae, except in the viscera; more larvae were seen in BALB/c or ICR than in B10.BR mice. No larvae were found in the secondary host mice. Present study demonstrated that B. potosis larvae migrate well in the carcass of any strains of mice, however, the tissue larvae did not infect the secondary host. Results of our present study suggest that B. potosis larvae is less aggressive for the nervous tissue migration than that of B. procyonis larvae which is commonly known to migrate in central nervous system of mammals and birds. [ABSTRACT FROM AUTHOR]

Chronic nonbacterial osteomyelitis is a rare bone disorder that can be found in the jaw. It is often associated with systemic conditions, including autoimmune deficiencies. However, little is known about how the genetic and immunologic background of patients influences the disease. Here, we focus on human leukocyte antigen (HLA), killer cell immunoglobulin-like receptors (KIRs), and their specific combinations that have been difficult to analyze owing to their high diversity. We employed a recently developed technology of simultaneous typing of HLA alleles and KIR haplotype and investigated alleles of the 35 HLA loci and KIR haplotypes composed of centromeric and telomeric motifs in 18 cases and 18 controls for discovery and 472 independent controls for validation. We identified an amino acid substitution of threonine at position 94 of HLA-C in combination with the telomeric KIR genotype of haplotype tA01/tB01 that had significantly higher frequency (>20%) in the case population than in both control populations. Multiple logistic regression analysis based on a dominant model with adjustments for age and sex revealed and validated its statistical significance and high predictive accuracy (C-statistic ≥0.85). Structure-based analysis revealed that the combination of the amino acid change in HLA-C and the telomeric genotype tA01/tB01 could be associated with lower stability of HLA-C. This is the first case-control study of a rare disease that employed the latest sequencing technology enabling simultaneous typing and investigated amino acid polymorphisms at HLA loci in combination with KIR haplotype. [ABSTRACT FROM AUTHOR]

Presents information on a study which discussed the transmission electron microscopy of ordered and modulated structures in InGaP alloy semiconductors on (001) gallium arsenide substrates. Results of the transmission electron diffraction pattern; Information on the atomic scale evaluation carried out on the crystals; Optical properties of InGaP crystals.

Presents a study which investigated the photoionization of deep traps in aluminum gallium arsenide/gallium arsenide multiple-quantum-well layers. Experiment; Results; Discussion.

Reaction cross sections for 15,16C on nuclear targets (Be, C, Al) and proton target are systematically measured in the intermediate energy range. Nucleon density distributions of 15,16C were deduced from the analyses of present data with existing experimental data using the Glauber-type calculation. Proton and neutron density distributions were also deduced separately from proton target data. Results of root-mean-square radii show a good agreement with theoretical calculations for both isotopes. [ABSTRACT FROM AUTHOR]

We have measured reaction cross sections (σR) for 13;14;15B on Be, C, Al, and proton targets. In addition to the conventional method of deducing nucleon density distributions based on the Glauber-type calculation, the recently developed method for deducing point-proton and neutron density distributions separately from σR on proton targets were utilized for these nuclei. The result suggests the necessity for 14B of a large tail in its neutron density distribution, which can be referred to as a one-neutron halo. Rootmean- square point-proton, neutron and matter radii for 13,14,15B were also derived. From present systematic studies for 13,14,15B, a large enhancement of matter and neutron radii in 14B was found for the first time. [ABSTRACT FROM AUTHOR]

We have developed a high time resolution time-of-flight (TOF) detector that detects the Cherenkov light emitted when an RI beam passes through a high refractive index glass. 58Ni and 132Xe beams of energies of 200A-500AMeV and secondary beams produced with those beams have been used for the test of the Cherenkov detectors. The time resolution of σ = 5 ps with the inclusion of system resolution has been achieved with a 420AMeV 132Xe beam. [ABSTRACT FROM AUTHOR]

Objective Ameloblastoma ( AM) shows locally invasive behaviour. However, biological investigations regarding regulation of gene expression associated with AM pathological features are difficult to perform, because AM cells can be passaged for a few generations due to senescence. We report a newly established immortalized AM cell line, AMB cells, by transfection with human telomerase reverse transcriptase ( hTERT). Furthermore, we examined whether TNF- α modulates bone resorption-related genes, IL-6 and MMP-9 in cooperation with TGF- β or IFN- γ. Materials and methods Following transfection of an hTERT expression vector into AM cells using a non-viral method, the effects of cytokines on the expressions of IL-6 and MMP-9 mRNA were examined using real-time PCR. TNF- α-induced NF- κB activity was examined by western blotting and transcription factor assays. Results AMB cells continued to grow for more than 100 population doublings. Stimulation with TNF- α increased IL-6 and MMP-9 mRNA expressions, as well as NF- κB activation. Furthermore, TGF- β and IFN- γ dramatically increased TNF- α-mediated expressions of MMP-9 and IL-6 mRNA, respectively, while those responses were suppressed by NF- κB inhibitor. Conclusion We established an immortalized AM cell line by hTERT transfection. TNF- α-mediated regulation of MMP-9 and IL-6 via NF- κB may play an important role in the pathological behaviour of AMs, such as bone resorption. [ABSTRACT FROM AUTHOR]

Objective Itraconazole (ICZ) has a broad spectrum of antifungal activity including a wide range of Candida spp. TNF-α, an inflammatory cytokine associated with Th1-mediated oral inflammatory disease, enhances inflammatory mediators, such as CXCR3-agonistic chemokines including CXCL10. We examined the anti-inflammatory potential of ICZ against TNF-α-induced chemokines in oral fibroblasts. Materials and methods We investigated the effects of ICZ on mRNA expressions of various TNF-α-induced chemokines in immortalized oral keratinocytes (RT7) and oral fibroblasts (GT1) using quantitative PCR analysis. Subsequently, the effects of ICZ and fluconazole (FLZ) on TNF-α-induced CXCL10 proteins in GT1 and primary fibroblasts were examined using enzyme-linked immunosorbent assays (ELISA). The effect of ICZ on signal transduction protein phosphorylation involved in CXCL10 production from TNF-α-stimulated GT1 was examined by western blotting. Results ICZ inhibited TNF-α-induced CXCL10 mRNA in GT1, but not RT7. Although ICZ did not affect TNF-α-induced IL-8 mRNA, the mRNAs of TNF-α-induced CXCR3-agonistic chemokines such as CXCL9 and CXCL11 were inhibited by ICZ in GT1. TNF-α-induced CXCL10 protein production in GT1 and primary fibroblasts was inhibited by ICZ, but not FLZ. Finally, ICZ inhibited TNF-α-induced phosphorylation of c-JUN, which is related to CXCL10 production by TNF-α-stimulated GT1. Conclusion ICZ may be useful as therapy for Th1-mediated oral inflammatory disease. [ABSTRACT FROM AUTHOR]

Objective Itraconazole (ICZ) has a broad spectrum of antifungal activity including a wide range of Candida spp. TNF-α, an inflammatory cytokine associated with Th1-mediated oral inflammatory disease, enhances inflammatory mediators, such as CXCR3-agonistic chemokines including CXCL10. We examined the anti-inflammatory potential of ICZ against TNF-α-induced chemokines in oral fibroblasts. Materials and methods We investigated the effects of ICZ on mRNA expressions of various TNF-α-induced chemokines in immortalized oral keratinocytes (RT7) and oral fibroblasts (GT1) using quantitative PCR analysis. Subsequently, the effects of ICZ and fluconazole (FLZ) on TNF-α-induced CXCL10 proteins in GT1 and primary fibroblasts were examined using enzyme-linked immunosorbent assays (ELISA). The effect of ICZ on signal transduction protein phosphorylation involved in CXCL10 production from TNF-α-stimulated GT1 was examined by western blotting. Results ICZ inhibited TNF-α-induced CXCL10 mRNA in GT1, but not RT7. Although ICZ did not affect TNF-α-induced IL-8 mRNA, the mRNAs of TNF-α-induced CXCR3-agonistic chemokines such as CXCL9 and CXCL11 were inhibited by ICZ in GT1. TNF-α-induced CXCL10 protein production in GT1 and primary fibroblasts was inhibited by ICZ, but not FLZ. Finally, ICZ inhibited TNF-α-induced phosphorylation of c-JUN, which is related to CXCL10 production by TNF-α-stimulated GT1. Conclusion ICZ may be useful as therapy for Th1-mediated oral inflammatory disease. [ABSTRACT FROM AUTHOR]

Oral Diseases (2012) 18, 756-762 Objectives: An odontoma, which shows proliferating odontogenic epithelium and mesenchymal tissue, is one of the most common odontogenic tumors encountered. These are commonly found in tooth-bearing regions, although the etiology remains unknown. There are no previous reports of an established line of immortalized human odontoma cells. Methods: Using odontoma fragments obtained from a girl treated at our department, we established an immortalized human odontoma cell line and investigated cell morphology, dynamic proliferation, the presence of contamination, and karyotype. Moreover, cell characterization was examined using osteogenic and odontogenic markers. Results: We successfully established a mesenchymal odontoma cell (mOd cells). The cells were found to be fibroblastic and had a high level of telomerase activity. Cell growth was confirmed after more than 200 population doublings without significant growth retardation. mOd cells expressed mRNA for differentiation markers, including collagen type I (COLI), alkaline phosphatase, bone sialoprotein, osteopontin, osteocalcin, cementum-derived protein (CP-23), dentin sialophosphoprotein (DSPP), and distal-less homeobox 3 (DLX3), as well as bone morphogenetic proteins (BMPs). In addition, they showed a high level of calcified nodule formation activity in vitro. Conclusions: We successfully established a cell line that may be useful for investigating the mechanisms of normal odontogenesis as well as characteristics of odontoma tumors. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to elucidate the incidence and risk factors for the progression of hypointense nodules observed in the hepatobiliary phase of gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA-enhanced MRI) of hypervascular hepatocellular carcinoma (HCC).Materials and Methods: Hypovascular nodules (112) showing hypointensity in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI were examined in 54 patients. All patients underwent computed tomography during hepatic arteriography and computed tomography during arterial portography (CTAP) within a month after Gd-EOB-DTPA-enhanced MRI. According to the tumor size, 112 nodules were divided into two groups: those >10 mm in diameter (group A, n = 39) and those ≤10 mm in diameter (group B, n = 73). The incidence of progression to hypervascular HCC was calculated using the Kaplan-Meier method.Results: The incidence of hypervascularization was significantly higher in group A nodules than in group B nodules (p < 0.0001). Tumor size (p < 0.0001) and hypoattenuation in CTAP (p = 0.0004) showed significant correlation with hypervascularization.Conclusion: Hypointense nodules observed in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI with diameters of >10 mm had a high probability of hypervascularization. [ABSTRACT FROM AUTHOR]

In this paper, the results of resistive wall mode (RWM) control experiments using several sets of active coils are presented. The control effectiveness as a function of coil number and covered torus surface is studied in the RFX-mod device, thanks to the powerful and flexible MHD active control system. Active control is tried using similar coil number and size both in the reversed field pinch (RFP) and in the tokamak configurations, giving a good experimental set to exploit the differences between the two cases. The experimental results are compared with predictions by a new integrated simulator for closed loop RWM growth. The numerical tool couples, in a self-consistent way, a full 3D finite element description of the machine boundaries, a 2D toroidal model of RFP plasma stability and a model of the RFX-mod control system, producing an overall dynamic model cast in the state variable space. In this way a full dynamic flight simulator of RWM control experiments is implemented, where coil coverage and experimental proportional-integral-derivative gains are explored in simulations. Both in the performed experiments and in simulations wall mode active control is proven to be possible in both the configurations with a very reduced set of active control coils. [ABSTRACT FROM AUTHOR]

An energetic-particle (EP)-driven 'off-axis-fishbone-like mode (OFM)' often triggers a resistive wall mode (RWM) in JT-60U and DIII-D devices, preventing long-duration high-βN discharges. In these experiments, the EPs are energetic ions (70-85 keV) injected by neutral beams to produce high-pressure plasmas. EP-driven bursting events reduce the EP density and the plasma rotation simultaneously. These changes are significant in high-βN low-rotation plasmas, where the RWM stability is predicted to be strongly influenced by the EP precession drift resonance and by the plasma rotation near the q=2 surface (kinetic effects). Analysis of these effects on stability with a self-consistent perturbation to the mode structure using the MARS-K code showed that the impact of EP losses and rotation drop is sufficient to destabilize the RWM in low-rotation plasmas, when the plasma rotation normalized by Alfvén frequency is only a few tenths of a percent near the q=2 surface. The OFM characteristics are very similar in JT-60U and DIII-D, including nonlinear mode evolution. The modes grow initially like a classical fishbone, and then the mode structure becomes strongly distorted. The dynamic response of the OFM to an applied n=1 external field indicates that the mode retains its external kink character. These comparative studies suggest that an energetic particle-driven 'off-axis-fishbone-like mode' is a new EP-driven branch of the external kink mode in wall-stabilized plasmas, analogous to the relationship of the classical fishbone branch to the internal kink mode. [ABSTRACT FROM AUTHOR]

The interaction cross-sections (σI) of neutron-rich Na isotopes, 23-35Na, on C target have been measured at 250A MeV using the RI beam factory (RIBF) at RIKEN. Mass dependence of σI for 27-35Na suggests monotonic growth of the skin thickness. The root-mean-square nuclear matter radii (r̃m) of 23-35Na were deduced from observed σI via a Glauber-type calculation. These r̃m are in a good agreement with the theoretical prediction by relativistic mean field model (RMF). r̃m of 33-35Na were determined for the first time. [ABSTRACT FROM AUTHOR]

Interaction cross sections (σI) for Ne isotopes from the stability line to the vicinity of neutron-drip line have been measured using the RIBF facility at RIKEN. Measurements have been performed for 20–32Ne on C target at energies around 240 MeV/nucleon. A large enhancement of σI beyond the systematics of stable nuclei have been observed for neutron-rich Ne isotopes. The possible halo structures with lower orbital angular momentum for 29,31Ne are discussed by the preliminary analysis. [ABSTRACT FROM AUTHOR]

Oral Diseases (2010) 16, 438–444 Objective: The purpose of this study was to develop a graft material made of gingival fibroblasts cultured in animal-free medium (HFDM1). Methods: We examined the effects of human serum (HS) on cell growth and wound healing capability, demonstrated by cytokine production, of gingival fibroblasts cultured in HFDM1. Subsequently, the capability of fibroblasts cultured in HFDM1 with 2% HS to promote the healing of skin defects was evaluated using nude mice. Results: The proliferation of human gingival fibroblasts was increased when HS at a concentration of 0.5–2% was added to HFDM1. Wound healing cytokines, including transforming growth factor-β, keratinocyte growth factor, hepatocyte growth factor, vascular endothelial growth factor, and IL-6 produced by gingival fibroblasts were increased by adding 2% HS to HFDM1. In addition, gingival fibroblasts cultured in HFDM1 with 2% HS improved wound healing of mouse skin defects as well as those cultured in Dulbecco’s modified Eagle’s medium with 10% fetal calf serum. Conclusion: Gingival fibroblasts cultured in HFDM1 with 2% HS may be useful as a graft material for reconstruction. [ABSTRACT FROM AUTHOR]

The β-NMR study of short-lived nucleus Cu ( I = 1, T = 3.2 s) in Si has been performed. Spin polarization of Cu induced by the charge exchange reaction of Ni was observed in Si at 15 K. The Cu magnetic moment $|\upmu[^{58}\mbox{Cu}]| = (0.46 \pm 0.03)\upmu_{\rm N}$ deduced from the β-NMR spectrum is consistent with the previous results on the laser spectroscopy. The present result shows that the Cu nucleus is promising as a new nuclear probe for the microscopic study of Cu impurities in Si. [ABSTRACT FROM AUTHOR]

Resonance frequency analysis (RFA) was introduced as a method for measuring implant stability more than a decade ago. Implant stability quotient (ISQ) values obtained using a recently introduced wireless RFA device have made it possible to evaluate stability in a non-invasive technique; however, there are few studies of the factors that affect ISQ values determined using this device. The aim of the present study was to evaluate the association between ISQ values determined by wireless RFA and various factors related to dental implant stability using a pig cortical bone model. Dental implants (Replace® Select Tapered implants) with a length of 10 mm were placed into pig cortical bone samples, then, ISQ values were determined using wireless RFA under various conditions (probe orientation, diameter of implant, insertion torque and peri-implant bone loss). The results of this study showed that ISQ values were not affected by the direction of the probe from parallel to perpendicular to the long axis of the pig bone or to the smart peg. In addition, the diameter of the implant did not have a significant effect on the measured ISQ values. Statistically significant correlations were found between insertion torque and ISQ values (Spearman’s test, P < 0·05), and lower ISQ values were observed for deeper peri-implant vertical defects (Mann–Whitney U-test, P < 0·05). A wireless RFA device appears to be useful for measuring implant stability within the limits of the present in vitro study. [ABSTRACT FROM AUTHOR]

Th1 and Th2 cytokines such as interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and IL-4 are expressed in T-cell-mediated inflammation in the oral cavity. We tested the hypothesis that those cytokines may act on CXCR3-agonistic chemokines, T-cell recruiting factors, and on neighboring cells, including oral keratinocytes and fibroblasts. Human immortalized oral keratinocytes (RT7) and fibroblasts (GT1) after 24-hour stimulation with IFN-γ showed increased mRNA levels of CXCL9 (600- and 700-fold), CXCL10 (10,000- and 150-fold), and CXCL11 (5000- and 300-fold), respectively. In contrast, TNF-α caused an increase in CXCL9 (300-fold), CXCL10 (2000-fold), and CXCL11 (2000-fold) mRNA levels in GT1, but not RT7 cells, at 24 hrs. IL-4 reinforced the promotion of CXCL9, CXCL10, and CXCL11 expression by IFN-γ in RT7 cells, whereas IL-4 inhibited the increased levels by IFN-γ and TNF-α in GT1 cells. Thus, IFN-γ, TNF-α, and IL-4 appear cooperatively to regulate CXCR3-agonistic chemokines in oral keratinocytes and fibroblasts in T-cell-mediated oral inflammation sites. [ABSTRACT FROM AUTHOR]

The electric quadrupole ( Q) moment of short-lived nucleus 25Al $(I^{\pi} = 5/2^{+}, T_{1/2} = 7.18~{\rm s})$ has been measured for the first time, by means of the β-NQR technique. The spin polarization of 25Al was produced in heavy ion collisions and was kept in a α-Al2O3 single crystal for as long as 2 s and the quadrupole coupling frequency was obtained as ∣ eqQ / h(25Al in Al2O3) ∣ = (4.05 ±0.30) MHz. From the result, the Q moment was determined as ∣ Q(25Al)∣ = (240 ±20) mb. The present Q moment is larger by 30% than the shell model value of 184 mb, calculated by OXBASH code, which may show additional deformation of the nucleus. [ABSTRACT FROM AUTHOR]

The results of particle-in-cell simulations of a negative neutral beam heated Alfvén-mode experiment in the Japan Atomic Energy Research Institute Tokamak-60 Upgrade (JT-60U) [H. Ninomiya et al., Fusion Sci. Technol. 42, 7 (2002); A. Kitsunezaki et al., ibid. 42, 179 (2002)] are presented. They seem to match quite well the dynamics of the abrupt large-amplitude event (ALE) experimentally observed in the reference JT-60U discharge. The time scale and frequency spread of the ALE are well reproduced too. The issue of the weaker Alfvén fluctuation phase following the ALEs, characterized by fast frequency sweeping modes, is also investigated and an interpretation of the full JT-60U bursting-mode phenomenology is presented. Finally, the simulation tool is exploited by ad hoc synthetic diagnostics on the fast ion distribution function to get a deeper insight into the ALE nonlinear dynamics. The underlying fast-growing energetic particle mode saturates as resonant energetic ions are scattered out of the resonance region and displaced outwards. The radially displaced ions resonate with outer Alfvén modes and enhance their local drive, consistently with the “avalanche” paradigm for mode nonlinear dynamics and energetic ion transports. [ABSTRACT FROM AUTHOR]

The multichannel motional Stark effect (MSE) diagnostic system in JT-60U has been upgraded to measure density fluctuation profile. A 16-channel fast-sampling digitizer has been added in order to measure photomultiplier-tube signals at measurement frequency of 0.5–1 MHz. The new system works as a MSE and beam emission spectroscopy diagnostic. Spatially resolved electron density fluctuation profile measurement in various operation regimes is presented. In the core plasma, density fluctuation induced by rotation of tearing mode islands was observed. Temporal evolution of the fluctuation frequency agrees with that measured by Mirnov coils (poloidal and toroidal mode numbers: 2 and 1, respectively). The phases of the fluctuations on either side of the q=2 surface are inverted, which is consistent with electron cyclotron emission. These measurements show that the density fluctuation is caused by a rotating magnetic island structure induced by the tearing mode. In the scrape-off layer of a H-mode plasma with edge-localized-mode (ELM), i. e., ELMy H-mode outward propagation of strong intermittent emission corresponding to ELM crash was also observed. The propagation velocity is 0.69–2.2 km/s along the MSE measurement points, the time lag and distance between adjacent channels being 67±35 μs and 70 mm, respectively. [ABSTRACT FROM AUTHOR]

Rapid frequency sweeping modes observed in reversed magnetic shear (RS) plasmas on the Japan Atomic Energy Research Institute Tokamak 60 Upgrade (JT-60U) [H. Ninomiya and the JT-60 Team, Phys. Fluids B 4, 2070 (1992)] have been identified as reversed-shear-induced Alfvén eigenmodes (RSAEs), which are ideal magnetohydrodynamic Alfvén eigenmodes (AEs) localized to the region of minimum safety factor, qmin, and are excited by negative-ion-based neutral beam injection. The chirping and subsequent saturation of the mode frequency are consistent with theoretical predictions for the transition from RSAEs to toroidal Alfvén eigenmodes (TAEs). The previously observed rapid frequency sweeping modes in ion cyclotron wave heated plasmas in JT-60U can also be similarly explained. The observed AE amplitude is largest during the transition from RSAEs to TAEs, and fast ion loss is observed when the AE amplitude is largest at this transition. It is preferable to operate outside the transition range of qmin, e.g., 2.4min<2.7 for the n=1 AE to avoid substantial fast ion loss in RS plasmas. [ABSTRACT FROM AUTHOR]

Energetic-ion driven instability in a Japan Atomic Energy Research Institute Tokamak-60 Upgrade (JT-60U) [S. Ishida et al., Phys. Plasmas 11, 2532 (2004)] plasma was investigated using a simulation code for magnetohydrodynamics and energetic particles. The spatial profile of the unstable mode peaks near the plasma center where the safety factor profile is flat. The unstable mode is not a toroidal Alfvén eigenmode (TAE) because the spatial profile deviates from the expected location of TAE and the spatial profile consists of a single primary harmonic m/n=2/1 where m and n are poloidal and toroidal mode numbers. The real frequency of the unstable mode is close to the experimental starting frequency of the fast frequency sweeping mode. Simulation results demonstrate that energetic-ion orbit width and energetic-ion pressure significantly broaden radial profile of the unstable mode. For the smallest value among the investigated energetic-ion orbit width, the unstable mode is localized within 20% of the minor radius. This gives an upper limit of the spatial profile width of the unstable mode which the magnetohydrodynamic effects alone can induce. For the experimental condition of the JT-60U plasma, energetic ions broaden the radial width of the unstable mode spatial profile by a factor of 3. The unstable mode is primarily induced by the energetic particles. [ABSTRACT FROM AUTHOR]

Sawtooth oscillations are often detected in the signals of several diagnostics during tangential neutral beam injection (NBI) heating in the compact helical system (CHS) [K. Matsuoka et al., Plasma Pysics and Controlled Nuclear Fusion Research, 1988 (International Atomic Energy Agency, Vienna, 1989), Vol. 2, p. 441]. The sawtooth crashes are closely related to the q=2 (q is the safety factor) rational surface located on the normalized minor radius p∼0.5 and most of the crashes indicate a character of an annular crash. The disturbance of plasma parameters on the magnetic axis depends on the toroidal plasma beta and the size of the q = 2 surface. The time scale of the crash is fairly large to he 0.5-1.0 ms which is an order of magnitude larger than that in tokamaks. Two types of m/n = 2/1 (m and n are poloidal and toroidal mode numbers, respectively) magnetic fluctuations, which are fishbone-like burst mode (FB) and low frequency ideal/resistive interchange mode (LF mode), grow just before the crash. Those internal structure and time evolution across the crash clearly indicate that the sawtooth crash in NBI heated plasmas of CHS is induced by ideal/resistive interchange mode not by energetic ion driven mode. [ABSTRACT FROM AUTHOR]

We have developed distributed amplifiers for high bit-rate fiber-optic communication systems. We have designed a LiNbO[sub 3] modulator driver using 0.15-µo double-doped AlGaAs/InGaAs/AlGaAs pseudomorphic HEMTs. We obtained a 15-dB gain and 54-GHz bandwidth with GCPW lines, and a fairly clear 6-V[sub p-p] output at 40 Gb/s. We also developed preamplifiers for both NRZ and RZ applications. Our preamplifier for the NRZ-data format has a 52-dBΩ gain and a 49-GHz bandwidth. It consists of a lumped element circuit and a distributed amplifier with InP-based HEMTs. We fabricated a module that consisted of the preamplifier connected to a photodiode, and confirmed a clear NRZ-output waveform at 40-Gb/s. The preamplifier with 0.15-µm double-doped AlGaAs/InGaAs/AlGaAs pseudomorphic HEMTs for the RZ-data format has an 11-dB gain and a 57-GHz bandwidth. We also developed a PIN/preamp module that has a 44-dBΩ gain and a 45-GHz bandwidth. The module showed a superior phase characteristic and produced a clear RZ eye-pattern. Furthermore, we fabricated an ultra-broadband amplifier for over--40-Gb/s applications. We obtained a 9-dB gain and 70-GHz bandwidth. These results demonstrate that a distributed amplifier is the best candidate for over-40-Gb/s fiber optic communication systems manuscript. [ABSTRACT FROM AUTHOR]

This article describes a diagnostic for measuring neutron emission profile in JT-60U. The Stilbene neutron detector, developed by TRINITI laboratory in Russia, has been installed on the JT-60U Tokamak to measure the neutron emission profile for the first time. The Stilbene neutron detector is a detector which combines a Stilbene crystal scintillator with a neutron-gamma pulse shape discrimination circuit, with a very compact size. Performance tests were carried out using neutron and gamma-ray source prior to installation on JT-60U. Good gamma suppression of the Stilbene neutron detector was verified. Though the neutron emission profile obtained by Stilbene neutron detectors has error of 30% in innermost channel with a calculation using measured plasma parameters, there is an agreement within 10% error in the other channels. [ABSTRACT FROM AUTHOR]

Postamplifier and p-i-n/preamplifier modules suitable for 40-Gb/s short-haul and long-haul optical communication systems are presented. The postamplifier module consists of two stages of pseudomorphic high-electron mobility transistor (PHEMT) GaAs amplifiers mounted in a housing. A test fixture is used to provide bias supplies that control the output signal. The postamplifier has a 20-dB gain and 4.5-dB noise figure. The input voltage swing of the postamplifier can be varied from 10 to 148 mV p-p while providing an open output eye-pattern response over the complete range. The p-i-n/preamplifier module consists of a waveguide p-i-n/photodetector, with a polarization insensitive spot-size converter and a PHEMT-based GaAs transimpedance amplifier. The components are integrated inside a hermetically sealed compact package using hybrid techniques. The p-i-n/preamplifier module having 150-Ω transimpedance exhibits a linear output voltage swing over 800 mV p-p and a responsivity of 0.8 A/W. The receiver module has a 3-dB bandwidth as high as 45 GHz, and the input equivalent noise current density is less than 15 pA/√(Hz). The electrical sensitivity of the postamplifier is found to be 7.8 mV p-p for a 40 Gb/s, 27-1 pseudorandom binary sequence nonreturn-to-zero signal. When used in combination with a 150-Ω 40-Gb/s p-i-n/preamplifier module, a sensitivity of less than -11.2 dBm is achieved. These results indicate that the postamplifier module, in combination with the p-i-n/preamplifier module, can be used in 40-Gb/s short-haul systems, while the p-i-n/preamplifier module itself can be used for long-haul front-end receiver systems. [ABSTRACT FROM PUBLISHER]

The tissue response to anti-washout apatite cement using chitosan (aw-AC(chi)) was evaluated by implanting aw-AC(chi) into bone defects of rat tibiae using conventional apatite cement (c-AC) as a control material. During the experimental period up to 16 weeks, the only difference between aw-AC and c-AC was found at two weeks in the tissue response of soft tissue. At two weeks, c-AC showed a moderate inflammatory response; small particles of c-AC were scattered in the cutaneous tissue and many foreign body giant cells were collected around the scattered c-AC, whereas aw-AC showed only a slight inflammatory response and few foreign body giant cells. We found no difference between aw-AC(chi) and c-AC with respect to bone tissue response. Both AC were almost completely surrounded by mature bone at eight weeks. No promotion or reduction of osteoconductivity was observed by chitosan even though it is considered to promote bone formation. We concluded, therefore, that enhancement of bone formation cannot be expected by employing chitosan to obtain anti-washout properties, at least in the concentration used in this study, even though aw-AC(chi) is much more useful than c-AC. © 2001 Kluwer Academic Publishers [ABSTRACT FROM AUTHOR]

Since 1993 sulphadoxine/pyrimethamine (SP) has been used as the first-line drug for uncomplicated Plasmodium falciparum malaria in Malawi. To investigate the current efficacy of SP and other antimalarial drug resistance, we studied in vivo and in vitro responses to SP, chloroquine (CQ), mefloquine (MF), quinine (QN), and halofantrine (HF) in Salima, central Malawi. In a follow-up of 14 days, nine (13.8%) of 65 children under five showed RII/RIII parasitological resistance, and in in vitro microtests 18 (62.1%) of 29 isolates showed < 90% inhibition of schizont maturation at pyrimethamine 75 nmol/l blood medium mixture, indicating resistance. The discrepancy between in vivo and in vitro results might be partially explained by acquired immunity in this holoendemic area. In vitro one (3.4%) of 29 isolates failed schizont inhibition at 1.6 micromol/l blood of CQ, indicating resistance. Compared with an in vitro study conducted in 1988 in another region of Malawi using the same cut-off point, the proportion of resistant isolates had decreased significantly (P < 0.01). Although 31% of isolates were borderline, showing schizont maturation at 0.8 micromol/l blood but no schizonts at 1.6 micromol/l in our study, the results suggest possible recovery of CQ sensitivity after long-term absence of drug pressure. Resistance remains a major problem in malaria control. Monitoring resistance patterns in vitro provides early warning signs of impending loss of therapeutic efficacy of the standard treatment, and may detect changing patterns in alternative drug resistance. [ABSTRACT FROM AUTHOR]

Four loop antennas are installed in the Compact Helical System (CHS) heliotron/torsatron in order to externally excite Alfve´n eigenmodes (AEs). These antennas are used in two different operation methods: one is as a set of four external loop antennas, and the other two pairs of electrodes inserted near the plasma boundary. For these two operations, magnetic perturbations in the frequency range of 10–250 kHz are generated in the plasma. The plasma response for the applied magnetic perturbations is measured by magnetic probe arrays. Information of AEs can be derived from the analysis of the response. In the excitation experiment of AEs using the “electrode method,” magnetic fluctuations are resonantly enhanced in a certain electron density during the afterglow of a neutral beam heated plasma, where no energetic ions exist. The fluctuations have the toroidal mode number n=1 and the frequency lies just above the lower bound of the toroidicity-induced Alfve´n eigenmode (TAE) gap in the plasma core region. The excited fluctuations are thought to be related to TAEs. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]