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To identify and characterize anti-citrullinated glucose-6-phosphate isomerase ( GPI) peptide antibodies in patients with rheumatoid arthritis ( RA). Nine GPI arginine-bearing peptides in human GPI protein were selected and cyclic citrullinated GPI peptides ( CCG-1-9) were constructed. Samples were obtained from RA ( n = 208), systemic lupus erythematosus ( SLE) ( n = 101), Sjögren's syndrome ( SS; n = 101) and healthy controls ( n = 174). Antibodies against CCG-1-9 were measured, and anti-citrullinated α-enolase-1 ( CEP-1), -cyclic citrullinated peptides ( CCP) and - GPI proteins antibodies were also examined. Patients with RA were genotyped for HLA- DRB1. The numbers of shared epitope ( SE) alleles were counted and compared with those of the autoantibodies. Rabbit GPI was citrullinated with rabbit peptidylarginine deiminase and immunoblot analysis of RA sera performed. The levels of autoantibodies were compared before and after treatment with TNF antagonists in 58 RA patients. Anti- CCG-2, -4 and -7 antibodies were detected in 25·5, 33·2 and 37·0% patients with RA, respectively, and these antibodies were very specific for RA (specificity, 98·1-99·7%). Altogether, 44·2, 86·1 and 13·9% of RA sera were positive for anti- CEP-1, - CCP and - GPI protein antibodies, respectively. Anti- CCG-2, -4 and -7 antibodies were correlated with anti- CCP and anti- CEP-1 antibodies and with the presence of HLA- DRB1 SE alleles. Citrullinated GPI protein was detected using RA sera. Treatment with tumour necrosis factor antagonists reduced significantly the levels of anti- CCG-2 and -7 but not of anti- CEP-1 antibodies. This is the first report documenting the presence of anti- CCG antibodies in RA. Anti- CCG-2 and -7 antibodies could be considered as markers for the diagnosis of RA and its disease activity. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports R&D progress of the MeV class accelerator, beam focussing technique and a high voltage (HV) bushing toward the ITER Neutral Beam system at JAEA. A H− ion beam of 320mA (current density: 140A/m2) was successfully accelerated up to 796keV by fixing air leak in the ion source chamber caused by heat loading due to backstream positive ions. From analyses of a three-dimensional beam trajectory, a countermeasure against beamlet deflection due to space charge repulsion among beamlets was identified to compensate the deflection by proper aperture offset in the electron suppression grid. For development of the HV bushing, a half-size (Ø800mm) mockup single stage bushing was manufactured and tested, that demonstrated the dc voltage holding capability of up to 220kV in a condition with vacuum inside. Electrostatic analyses and design of the HV bushing are in progress, in which some design improvements are suggested to reduce electric field strength on the surface of ceramic insulator. [Copyright &y& Elsevier]

Abstract: Thermal annealing effects on Zn+ ion-implanted silica glass (a-SiO2) have been studied in order to control void formation. Void formation in a-SiO2 with Zn+ ion implantation and subsequent oxidation has been observed using transmission electron microscopy (TEM). Zn+ ions of 60keV were implanted into a-SiO2 to a fluence of 1.0×1017 ions/cm2. After the implantation, thermal annealing at 600 or 700°C for 1h in oxygen gas was conducted. In as-implanted state, metal Zn nanoparticles (NPs) of 10–15nm in diameter are formed in the depth region around the projected range. The size of the Zn nanoparticles increases after the annealing at 600°C in oxygen gas. Annealing in oxygen gas at 700°C for 1h caused two processes: (1) the migration of Zn atoms which formed Zn NPs in as-implanted state to the surface of the a-SiO2 substrate and (2) the transformation to the oxide phase on the substrate. The transportation of Zn NPs to the surface leaves voids of 10–25nm in diameter inside the a-SiO2. These results indicate that the oxidation at 700°C for 1h causes the migration of Zn atoms to the surface without diffusion and recombination of vacancies which form the voids. [Copyright &y& Elsevier]

In the present study, 10 greater amberjack Seriola dumerili held individually were given free access to self-feeder, and trigger actuations were continuously monitored. Most (80%) of greater amberjack developed stable self-feeding activity within 1 week. The fish was a rigidly diurnal feeder under a 12L:12D cycle, with a feeding peak of 1–3 h occurring just after the onset of lights. Under constant conditions, all 10 individual fish exhibited free-running self-feeding rhythms, which persisted for 43 days without a sign of damping out. As far as is known, this seems to be the longest record of free-running behavioural rhythms in fishes. Except one fish free-ran at a period length (τ) of 25·2 h, τ of free-running self-feeding rhythms in the other nine fish was shorter than 24 h, ranging from 20·0 h to 21·5 h. In addition, phase transients of feeding activity were observed in response to the advancement of lights on. It is concluded that feeding activity in greater amberjack is mediated by endogenous circadian oscillators. [ABSTRACT FROM AUTHOR]

the article focuses on the solutions of semilinear heat equations which blow up at space infinity. Results of studies on these problem consider either bounded domains or solutions decaying at space infinity. However, an author who has studied various nonlinear terms has proved that a solution blows up only at space infinity.

Abstract: Silica glasses (SiO2) were implanted with Zn+ ions of 60keV to a fluence of 1.0×1017 ions/cm2, and were annealed in oxygen gas flow at 700°C for 1h, to form ZnO nanoparticles (NPs). In as-implanted state, metallic Zn NPs of 10–15nm in diameter are formed between 10 and 50nm in depth. NPs are not observed on the surface and down to 10nm in depth. After the annealing at 700°C for 1h in oxygen gas, ZnO NPs of ∼10nm in diameter are observed around 50nm in depth. Moreover, droplet-like ZnO NPs larger than 30nm in diameter grow on the surface of SiO2 substrate. Migration of Zn atoms toward the surface, i.e., shallowing of the depth profile, is observed under the oxygen annealing, while vacuum annealing at the same temperature 700°C does not induce any prominent migration of Zn atoms. Mechanisms of the shallowing and the formation of ZnO NPs are discussed. [Copyright &y& Elsevier]

Abstract: In the negative ion based neutral beam injector (N-NBI) for JT-60U, an extension of the pulse duration up to 30s has been intended to study quasi-steady state plasmas, where the NBI pulse duration is significantly longer than the plasma current diffusion time. Achieving long pulse injection requires a reduction of the heat load on the grids of the ion source. The ion source was modified to reduce the pressure within the grid structure by increasing the vacuum conductance of the acceleration grids. The acceleration efficiency was improved from 0.74 to 0.79. The heat load of the grounded grid, which was the main heat load of the acceleration grids, decreased from 9.2 to 7.0% at a constant arc chamber pressure of 0.3Pa. These improvements seemed to be caused by the reduction of beam ion stripping loss. Up to now, a long pulse injection of 17s at the power of 1.6MW with beam energy of 366keV was obtained by using one ion source. The temperature rise of the cooling water from the grounded grid saturated at less than 35°C during operation, so the heat load of the grid is significantly reduced for steady state operation at this power level. [Copyright &y& Elsevier]

Abstract: Negative ion implantation has been applied to polymers in order to modify the surface and to fabricate nanoparticles. Metal nanoparticles in the vicinity of a polymeric surface are promising for biomedical applications as well as nonlinear optical applications. Substrates of polymethyl methacrylate (PMMA) were implanted with Ag− and Cu− of 60 keV at 3 μA/cm2 up to 3×1017 ions/cm2. Optical absorption spectra of the implanted PMMA were measured in a photon range from 0.5 to 4.5 eV. A peak of surface plasmon resonance (SPR) emerges in the absorption spectra above about 1×1017 ions/cm2, both for the Ag− and Cu− cases. A coexisting absorption slope, due mostly to defects, increases but tends to saturate with ion fluence. The SPR peak of Ag-implanted PMMA is much broader than that of the Cu-implanted one. Corresponding to the SPR spectra, metal nanoparticles are observed by cross-sectional TEM. With increasing ion fluence, the Ag nanoparticles spread out towards the surface, in contrast to the localized Cu nanoparticles. The results demonstrate that metal nanoparticle fabrication in polymers is capable by using appropriate low-energy ions and provides a variety of spatial distributions dependent on ion species and fluence. In particular, Ag− ion implantation fabricates surface-exposed/gradient nanoparticles, which are suitable for biomedical applications such as anti-microbial effects. [Copyright &y& Elsevier]

Abstract: Formation processes of nickel oxide (NiO) nanoparticles (NPs) in silica glass (SiO2) by implantation of 60keV Ni− ions combined with thermal oxidation are studied using cross-sectional transmission electron microscopy (XTEM) and Rutherford backscattering spectrometry. In as-implanted state, Ni metallic NPs form within the surface layer of ∼80nm thick. The mean depth 〈z〉 and the standard deviation 〈(Δz)2〉1/2 of Ni atom distribution determined by XTEM were 43 and 15nm, respectively. After the oxidation at 800°C for 1h, 〈z〉 and 〈(Δz)2〉1/2 became 47nm and 20nm, respectively, i.e. the distribution was almost the same except a small diffusional shift to the deeper region. Mean volume of Ni- and NiO-NPs after heat treatments at 800°C were 27 and 43nm3, respectively. The larger mean volume of NiO-NPs is explained from the fact that NiO-NPs include both Ni and O atoms, i.e. approximately 2N atoms, while Ni-NPs include Ni atoms only, i.e. N atoms. Both the Ni- and NiO-NPs include 2.4×103 Ni atoms per NP in average. These results indicate that NiO-NPs are formed by oxidation of Ni-NPs without pronounced redistribution of Ni atoms. [Copyright &y& Elsevier]

Implantation of Cu negative ions of 60 keV induces frequency shifts of infrared (IR) vibration modes of SiO2. Since the penetration depth of IR light is much larger than the projectile range of Cu- ions, conventional IR reflection spectroscopy detects little shifts. To evaluate the true shifts induced by the implantation, the near-surface sensitive IR reflection spectroscopy (NSS-IRRS) was applied using a suitable sample structure. Distinct shifts of -5, +6 and -44 cm-1, respectively, are observed in rocking, bending and stretching modes of Si–O–Si bonding of SiO2. Ion-flux dependence was examined in the flux range of 0.95–100 μA/cm2 with keeping the total fluence 3×1016 ions/cm2. Almost no ion-flux dependence is observed in the shifts of these modes, which is in contrast with the strong flux dependences of size- and depth-distributions of Cu nanoparticles in SiO2. [Copyright &y& Elsevier]

Purpose : To examine the heat sensitivity of DNA-dependent protein kinase (DNA-PK) activity in a variety of cultured mouse, hamster and human cell lines. Materials and methods : Eight cell lines, which have been routinely used in our laboratory, were examined. Cells were heated at 44.0±0.05°C and DNA-PK activity was measured by a DNA-pull-down assay followed by gel-electrophoresis. Cellular sensitivity to hyperthermia and/or X-ray was evaluated by a colony formation assay. Results : In mouse FSA1233 and FM3A cells, DNA-PK activity dropped to 15-16% of unheated control after 20 min of heating. In Chinese hamster V79 and CHO-K1 cells, kinase activity did not change appreciably after 20 min treatment but decreased to 60-70 and 22-23% after 40 or 60 min treatment, respectively. However, even after 180 min treatment, DNA-PK activity remained almost intact in human MOLT-4, MKN45 and A7 cells, and decreased only slightly in U937 cells. Hyperthermic radiosensitization was seen even in human cells but, as a trend, it was small compared with rodent cells. Conclusions : The heat sensitivity of DNA-PK was clearly different among mouse, hamster and human cells. The results suggested a possibility that the role of DNA-PK inactivation in hyperthermic radiosensitization might be variable, depending on cells, and would reinforce the warning that the direct extrapolation of data from rodent cells might lead to overestimation of the effectiveness of hyperthermia on human cancer. [ABSTRACT FROM AUTHOR]

Ion irradiation induces a frequency shift of Si–O–Si stretching vibration (ω4 mode, ∼1100 cm−1) in SiO2. Since the penetration depth of IR light is much larger than the projectile range of low-energy heavy ions (∼200 keV or less), conventional IR reflection spectroscopy detects a smaller shift than the true one. The near-surface sensitive reflection spectroscopy (NSSRS) was applied using a suitable sample structure, and obtained the true shift of ∼44 cm−1. The coherent two-layer reflection model, with the true shift value, well reproduces the spectra of the irradiated SiO2, and indicates that the ion-induced ω4 peak shift obtained with NSSRS has the same origin with the ion-induced 1040 cm−1 shoulder obtained with conventional spectroscopy. The present results indicate that the ω4 peak shift is ascribed not to the compaction, but to the Si–O–Si bond-breaking. [Copyright &y& Elsevier]

Metal nanoparticle formation and radiation resistance of polymers with heavy ion implantation have been studied to develop modification process of the optical properties of polymers. Negative Cu ions of 60 keV were implanted into high-density polyethylene (HDPE), polystyrene (PS) and polycarbonate (PC) at 1 μA/cm2 up to a total dose of 1.5 × 1017 ions/cm2. Optical absorption spectra at high total doses show surface plasmon resonance, indicating formation of Cu nanoparticles for all the polymers. The onset dose at which the plasmon peak appears depends on the polymer species. The metal nanoparticle formation in polymers is confirmed by cross-sectional TEM. Depth profiles of Cu atoms evaluated by RBS do not indicate distinct ion-induced diffusion. The FTIR-ATR spectra show fairly good resistance against radiation damage in the order of PC, PS and HDPE. These results indicate that low energy Cu− irradiation at appropriate doses does not cause serious damage on the polymer matrices, and that Cu atoms implanted into the polymers cause nanoparticle precipitation to be promising for optical application. [Copyright &y& Elsevier]

Simultaneous laser irradiation under ion irradiation is conducted to control nanoparticle precipitation in amorphous (a-)SiO2. Copper ions of 3 MeV and photons of 532 nm by Nd:YAG laser are irradiated to substrates of a-SiO2. The ion dose rate and total dose are set at 2–10 μA/cm2 and 3.0 × 1016–3.0 × 1017 ions/cm2, respectively, and the laser power density is 0.05–0.2 J/cm2 pulse at 10 Hz. The laser is simultaneously irradiated with ions in the co-irradiation mode, and the result is compared to that in the sequential and ion-only irradiation. Cross-sectional TEM of the irradiated specimens is conducted after measuring optical absorption spectra. In the case of co-irradiation of intense laser power and high dose (0.2 J/cm2 pulse and 3.0 × 1017 ions/cm2), Cu nanoparticles precipitate much more extensively than in the sequential irradiation, increasing both the particle diameter and the total Cu atoms in the nanoparticles. The optical absorption spectra show a surface plasmon peak of the nanoparticles. The precipitation enhancement in the co-irradiation mode suggests that the electronic energy is absorbed by the dynamic electronic states and promotes the Cu precipitation via enhancing the atomic migration. [Copyright &y& Elsevier]

Amorphous (a-) SiO2 substrates were irradiated with 30 keV Au−, 60 keV Au− and Au2− ions up to total dose 1 × 1017 atoms/cm2. The growth of metal nanoparticles in the implanted layer was observed by cross-sectional transmission electron microscopy. Optical absorbance spectra of all implanted specimens exhibited a distinctive peak associated with a surface plasmon resonance of Au nanoparticles. The resonance energy and spectral shape of the absorbance spectra are similar in case of monoatomic and diatomic Au ion bombardment. The spectral similarity in the low-energy implanted samples reflects the importance of post-collision processes, such as diffusion and thermodynamic processes in metal nanoparticle formation. [Copyright &y& Elsevier]

Ion-induced photon emission under 60 keV Cu− implantation into the insulators of MgAl2O4 and LiNbO3 was in situ measured over a wide wavelength range from 200 to 900 nm. The formation of the Mg and Li deficient layers for the respective insulator was detected based on the dose dependence of the Al, Mg and Li atomic line intensities. The Al I and Mg I line intensities from spinel exhibit different behaviors depending on irradiation temperatures: they gradually decrease while the (Al I)/(Mg I) ratio increases up to dose of 3×1017 ions/cm2 at room temperature or exhibits a steady-state tendency at high temperature. Sharp decrease of Li I line intensity from LiNbO3 under high dose rate bombardment indicates drastic changes of surface layer that may alter the phase stability and optical performance of insulators. [Copyright &y& Elsevier]

High power and long-pulse negative ion extractor, which is composed of the plasma grid (PG) and the extraction grid (EXG), is newly developed toward the neutral beam injector for heating and current drive of future fusion machines such as ITER, JT-60 Super Advanced and DEMO reactor. The PG is designed to enhance surface production of negative ions efficiently by applying the chamfered aperture. The efficiency of the negative ion production for the discharge power increased by a factor of 1.3 against that of the conventional PG. The EXG is also designed with the thermal analysis to upgrade the cooling capability for the long pulse operation of >1000 s required in ITER. Though the magnetic field for electron suppression is reduced to 0.75 of that in the conventional EXG due to this upgrade, it was experimentally confirmed that the extracted electron current can be suppressed to the allowable level for the long pulse operation. These results show that newly developed extractor has the high potential for the long pulse extraction of the negative ions. [ABSTRACT FROM AUTHOR]

In order to realize neutral beam systems in International Thermonuclear Experimental Reactor whose target is to produce a 1 MeV, 200 A/m² during 3600 s D- ion beam, the electrostatic five-stages negative ion accelerator so-called "MeV accelerator" has been developed at Japan Atomic Energy Agency. To extend pulse length, heat load of the acceleration grids was reduced by controlling the ion beam trajectory. Namely, the beam deflection due to the residual magnetic field of filter magnet was suppressed with the newly developed extractor with a 0.5 mm off-set aperture displacement. The new extractor improved the deflection angle from 6 mrad to 1 mrad, resulting in the reduction of direct interception of negative ions from 23% to 15% of the total acceleration power, respectively. As a result, the pulse length of 130 A/m², 881 keV H- ion beam has been successfully extended from a previous value of 0.4 s to 8.7 s. This is the first long pulse negative ion beam acceleration over 100 MW/m². [ABSTRACT FROM AUTHOR]

Samples of silica glass (SiO2) implanted with 60 keV Zn ions to a fluence of 1.0×1017 ions/cm2 were annealed in oxygen gas to form ZnO nanoparticles (NPs). Although the ZnO NPs were formed mainly on the SiO2 surface after oxidation at 700 °C for 1 h, they were formed inside the SiO2 substrate after lower temperature and long-duration oxidation at 500 °C for ∼70 h, i.e., the embedment of ZnO NPs in SiO2 was attained. The embedded NPs show a slightly stronger exciton peak and much weaker defect luminescence than the NPs formed on the surface. [ABSTRACT FROM AUTHOR]

Nanocrystals (NCs) of cuprous oxide (Cu2O), cupric oxide (CuO), and copper metal (Cu) are fabricated in silica glasses (SiO2) by implantation of 60 keV Cu- ions at different annealing conditions. At room temperature, Cu2O NCs show two sharp absorption peaks at 2.58 and 2.71 eV due to autoionized exciton states, and Cu NCs show a broad peak at ∼2.2 eV due to the surface plasmon resonance (SPR). With decreasing temperature down to 2.8 K, the peaks of Cu2O NCs become much narrower, while the SPR peak of Cu NCs keeps almost the same peak width. [ABSTRACT FROM AUTHOR]

Silica glass implanted with Zn ions of 60 keV to 1.0×1017 ions/cm2 was annealed in oxygen gas to form ZnO nanoparticles (NPs). In as-implanted state, the implanted Zn atoms form Zn metallic NPs inside of the silica. After annealing at 600 °C, ZnO NPs form on the surface, while Zn metallic NPs still remain in the deep region. At 700 °C, most of Zn atoms move to the surface to form the droplet-shaped ZnO NPs which show two photoluminescence bands, i.e., an exciton band at 375 nm and a defect band at ∼500 nm. The defect band almost disappears in the samples annealed at 600 °C, which include both ZnO NPs and Zn NPs. [ABSTRACT FROM AUTHOR]

In the JT-60U negative-ion-based neutral beam injection system, the effect of negative ion and electron deflection by the plasma grid (PG) magnetic filter was studied. After a long-pulse operation of up to 19 s, a local melting was observed on the beamline near the ion source, facing the electron drift side of the PG magnetic field. It is confirmed that the experimental deflection of the negative-ion beam agrees well with the three-dimensional beam simulation result by taking account of the measured magnetic field. By using the code, it is found that some stripped electrons produced in the first acceleration gap pass through the down pitch of the multiple apertures in the next stage of acceleration grids, and then collide on the beamline around the melted location. [ABSTRACT FROM AUTHOR]

Zinc-oxide (ZnO) nanoparticles (NPs) are fabricated in silica glasses (SiO2) by implantation of Zn+ ions of 60 keV up to 1.0×1017 ions/cm2 and following thermal oxidation. After the oxidation at 700 °C for 1 h, the absorption in the visible region due to Zn metallic NPs disappears and a new absorption edge due to ZnO appears at ∼3.25 eV. Cross-sectional transmission electron microscopy confirms the formation of ZnO NPs of 5–10 nm in diameter within the near-surface region of ∼80 nm thick and larger ZnO NPs on the surface. Under He–Cd laser excitation at λ=325 nm, an exciton luminescence peak centered at 375 nm with FWHM of 113 meV was observed at room temperature. [ABSTRACT FROM AUTHOR]

A method is proposed to synthesize oxide nanoparticles in insulators, using metal-ion implantation and following thermal oxidation, which introduces less damage compared to the sequential implantation of metal ions and oxygen ions. Ni-oxide nanoparticles are formed in O2 gas flow at ∼800 °C for 1 h, through thermal oxidation of Ni metal nanoparticles, which were introduced in SiO2 by charging-free negative ion implantation of 60 keV. After the oxidation, optical absorption in the visible region, which is due to Ni metal nanoparticles in the specimen, disappears, and a steep absorption edge of insulator NiO appears around ∼4 eV. Simultaneously, the large magnetization of Ni metal nanoparticles changes to a weak magnetization of antiferromagnetic NiO nanoparticles. The nanoparticle formation is confirmed by transmission electron microscopy observation. [ABSTRACT FROM AUTHOR]

The negative ion based neutral beam injector heating system for JT-60U has contributed to core plasma heating and noninductive current drive experiments on JT-60U. For increasing further the beam power and beam pulse duration, the serious issue is improvement of source plasma nonuniformity in the ion source. Various countermeasures have been devised to solve the nonuniformity. The first is to adjust the spatial distribution of the arc discharge through regulating the arc current limiting resistors to be connected in series to each of the filament groups. The second is to change the arc discharge mode through controlling the filament temperature. These measures have been found to be very effective. [ABSTRACT FROM AUTHOR]

This research revisits the analysis of roll motion and the possible capsize of floating vessels in beam seas. Many analytical investigations of this topic have adopted the softening Duffing equation, which is similar to the ship roll equation of motion. Here we focus on the loss of stability of periodic oscillations and its relevance to ship capsize. Previous researchers have found the thresholds of the saddle-node, flip, and heteroclinic bifurcations. They derived the flip condition from the negative stiffness condition in a Mathieu type variational equation. In our revisited analysis, we show that this threshold is identical to a pitchfork bifurcation. On the other hand, we simultaneously find that the generated asymmetry solution is unstable due to the limitation of the first order analysis. [ABSTRACT FROM AUTHOR]

This study investigated the molecular and pharmacokinetic mechanisms of the enhanced antiviral efficacy associated with pegylated interferon (PEG-IFN) alpha-2b and ribavirin. The study involved comparing the expression of serial double-stranded RNA-activated protein kinase (PKR) before and during treatment in 26 PEG-IFN alpha-2b and 26 conventional IFN alpha-2b recipients matched for age, body weight and dose of ribavirin. The pharmacokinetics of PEG-IFN alpha-2b and ribavirin was analysed in 15 of the 26 PEG-IFN recipients. There was a rapid increase in PKR expression in both treatment groups, although expression from day 2 onwards was maintained at a significantly higher level in the PEG-IFN recipients ( P < 0.05). Cmax of PEG-IFN occurred 12–48 h after the initial administration, with t1/2 and Cmin being 49 h and 190 pg/mL, respectively. In contrast to ribavirin, accumulation of PEG-IFN was minimal. There was no association between serum PEG-IFN and ribavirin levels and virological response. Although baseline expression of PKR before treatment was marginally higher in nonresponders (NRs), from day 2 onwards, sequential PKR expression in response to PEG-IFN was higher in sustained viral responders compared with the NRs ( P < 0.05). Significant correlations were found between kinetics of PKR expression and viral decline rates in each phase of hepatitis C virus dynamics (first phase, r = 0.67, P = 0.0006; second phase, r = 0.67, P = 0.001). In conclusion, improvement in pharmacokinetics following pegylation led to higher intracellular PKR expression, which was associated with enhanced virological efficacy of PEG-IFN-based combination therapy. The concentrations of both ribavirin and PEG-IFN alpha-2b were not associated with viral response and PKR expression. [ABSTRACT FROM AUTHOR]

Abstract: Surface recession due to sputtering under low-energy and high-fluence heavy-ion implantation makes shallower and broader depth profile of implanted ions than those calculated by conventional ion-range simulation-codes such as SRIM. Depth profiles of Zn atoms in silica glasses (SiO2) implanted with Zn+ ions of 60keV up to 1.0×1017 ions/cm2 were evaluated using both experimental methods as Rutherford backscattering spectrometry (RBS), sputtering depth-profiling by X-ray photoelectron spectroscopy (XPS), and an advanced numerical simulation code TRIDYN, which includes the sputtering loss effects. The TRIDYN code predicts the shallowing of the projectile range from ∼46 to ∼27nm with increasing the fluence up to 1×1017 ions/cm2, and very high-concentration (∼20at%) of Zn atoms close to the surface. However, RBS and XPS results exclude such high concentration close to the surface. These results suggest remarkable redistribution of Zn atoms from the nearer surface to the deeper region during the implantation. In fact, Zn-atom concentration near the surface and that near the projectile range are, respectively, lower and higher than those by the SRIM code predictions. [Copyright &y& Elsevier]

Magnetic nanoparticles are fabricated in silica glass (SiO2) using high-flux implantation of 60 keV negative nickel ions Ni-. Photo-absorption measurements and cross-sectional transmission electron microscopy (XTEM) observation confirm the formation of metallic Ni nanoparticles in SiO2, and exclude the possible formation of Ni silicides (Ni3Si, Ni2Si, NiSi) and oxides (NiO) as major products. The mean diameter of the nanoparticles was ∼2.9 nm, and the observed depth distribution was similar to a prediction from the TRIDYN code when sputtering was accounted for. Temperature- and field-dependences of magnetization show that the nanoparticles are in the superparamagnetic state at T>∼50 K. From the peak temperature of the zero-field cooling (ZFC) magnetization, which is ∼27 K, and the mean diameter determined from XTEM, it is suggested that the magnetic anisotropy constant K of the nanoparticles is enhanced by ∼8 times as compared to the bulk value. [Copyright &y& Elsevier]

Metal nanoparticles embedded in insulators exhibit a strong surface resonance and have been studied for optical switching. In this study, negative Cu ions of 60 keV were implanted into a-SiO2, MgO · 2.4(Al2O3) and LiNbO3 at 10–50 μA/cm2 to 1 × 1017 ions/cm2. The resultant nanoparticle morphology was studied by cross-sectional TEM and shown to depend on the substrate species. The a-SiO2 showed the formation of spherical Cu nanocrystals of ∼10 nm. The MgO · 2.4(Al2O3) suppressed particle coarsening even at high dose rates, sustaining crystallinity of the lattice. On the other hand, the LiNbO3 exhibited non-spherical Cu nanocrystals of ∼10 nm. Ion-induced photon spectroscopy was applied to monitor the ion–substrate interactions from outside of the substrates. The non-linear optical properties were evaluated by a pump–probe method around the plasmon energy of about 2 eV. Although LiNbO3 exhibited a sub-picosec non-linear response, ion-induced photon spectroscopy revealed Li-atom release to the vacuum under ion implantation, influencing the Cu nanoparticle formation. [Copyright &y& Elsevier]

In a multi-aperture multi-grid accelerator of the ITER neutral beam injector, the beamlets are deflected due to space charge repulsion between beamlets and beam groups, and also due to magnetic field. Moreover, the beamlet deflection is influenced by electric field distortion generated by grid support structure. Such complicated beamlet deflections and the compensations have been examined utilizing a three-dimensional beam analysis. The space charge repulsion and the influence by the grid support structure were studied in a 1/4 model of the accelerator including 320 beamlets. Beamlet deflection due to the magnetic field was studied by a single beamlet model. As the results, compensation methods of the beamlet deflection were designed, so as to utilize a metal bar (so-called field shaping plate) of 1 mm thick beneath the electron suppression grid (ESG), and an aperture offset of 1 mm in the ESG. [ABSTRACT FROM AUTHOR]

Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A/m2 (346 mA) where the 3 × 5 apertures were used. Measurement of the beam profile revealed that deflection of the H- ions was large and a part of the H- ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A/m2 (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A/m2). [ABSTRACT FROM AUTHOR]

A multiaperture multigrid accelerator called “MeV accelerator” has been developed for neutral beam injection system of international thermonuclear experimental reactor. In the present work, long pulse H- ion beam acceleration was performed by the MeV accelerator equipped with new water-cooled grids. At present, the pulse length was extended to 5 s for the beams of 750 keV, 221 mA, and 10 s for the beams of 600 keV, 158 mA. Energy density, defined as products of beam energy (keV), current (mA), and pulse (s) divided by aperture area (m2), increased more than one order of magnitude higher compared with original MeV accelerator without water cooling in its grids. At higher energy and current, the grid was melted by beam deflection. Due to this grid melting, breakdowns occurred between the grids, and hence, the pulse length was limited. Beam deflection will be compensated by aperture displacement in next experiment. [ABSTRACT FROM AUTHOR]

The H- ion accelerator R&D to realize the international thermonuclear experimental reactor neutral beam is ongoing at Japan Atomic Energy Agency (JAEA). The required performance for the prototype MeV accelerator developed at JAEA is 1 MeV, 500 mA (current density of 200 A/m2) H- ion beam at the beamlet divergence angle of less than 7 mrad. Up to 2005, 836 keV, 146 A/m2 H- ion beam was successfully accelerated as the highest record of the current density at MeV class energy beams. In the present work, high current negative ion beam acceleration test was performed by increasing the beam extraction apertures from 3×3 (9 apertures) to 3×5 (15 apertures). By fixing the air leak at the source chamber due to backstream ions as well as the improvement of voltage holding capability by a new fiber reinforced plastic insulator ring, the performance of the MeV accelerator was improved. So far, H- ion beam of 320 mA was successfully accelerated up to 796 keV with the beam divergence angle of 5.5 mrad. The accelerated drain current including the electron reaches close to the power supply limit for the MeV test facility. The heat flux by the backstream ion during the above beam acceleration was estimated to be 360 W/cm2. The Cs leakage to the accelerator during the test campaign (Cs total input of 5.0 g) was 0.26 mg (7.0 μg/cm2). This is considered to be the allowable level from the viewpoint of voltage holding. [ABSTRACT FROM AUTHOR]

To realize stable negative ion beams for 100 s required in the neutral beam injector of JT-60SA, a physical model to control cesium (Cs) distribution inside the negative ion source has been developed in order to maintain the stable negative ion production at the plasma grid (PG) surface with Cs. In this work, to quantitatively evaluate Cs coverage on the PG, a three-dimensional Cs transportation code was introduced to consider the spatial Cs distribution in the source. The spatial temperature distribution of the chamber wall was also introduced in this model. As a result, the reasonable variation of the Cs coverage for 100 s was obtained, compared to that in the initial model. Based on the modified model, the operational temperature of the chamber wall was proposed to be less than 60 °C to suppress the desorption of Cs in the chamber wall and to sustain the stable negative ion production. In addition, it was also suggested that a slightly higher wall temperature before the operation leads to a decrease in the amount of Cs stored at the chamber wall, resulting in suppression of Cs consumption in the ion source. [ABSTRACT FROM AUTHOR]

Long pulse acceleration of hydrogen negative ion beams with the power density over 70 MW/m2 and the pulse length over 100 s has been demonstrated for the first time by using a multi-aperture 3-stage accelerator. Such long pulse acceleration was achieved by integrating the design of beam optics and voltage holding capability to meet the requirements of JT-60SA. By using the newly designed accelerator for JT-60SA, voltage holding at 500 kV with beam acceleration was stably sustained even after 5 g of cesium was seeded, and heat load on each acceleration grid was reduced below the allowable level for long pulse, less than 5% of total acceleration power. As a result, 500 keV, 154 A/m2 for 118 s beam acceleration was achieved, which satisfies the requirement of the negative ion source for JT-60SA. This pulse length of such high-power density beams is longest in the world. In addition, the result contributes to the long pulse acceleration of multi-stage electrostatic accelerators, such as 1 MeV negative ion accelerator for ITER. [ABSTRACT FROM AUTHOR]

In order to reduce the tritium inventory in a fuel circulation system in fusion plants, a possibility of deuterium-tritium (DT) mixed neutral beam injectors with DT negative ion beams has been investigated by analyzing the beam optics of the DT-mixed negative ion beams for the first time. In a two-dimensional beam analysis, DT-mixed ion beams could be accelerated regardless of the DT current mixing ratio (T/D) from the identical acceleration geometry with the identical applied voltages by adjusting total space charge for the D and T components. However, in a three-dimensional beam analysis including magnetic fields, the DT-mixed ion beams were separated due to a mass dependence of the beam deflection by orthogonal magnetic fields of an electron suppression and transverse filter fields for negative ion production. In the case of the beamline for ITER, which requires beam deflection angle within ±1 mrad, the operational range for the DT-mixed ion beams was found to be the DT current mixing ratio of 0.7-1.5 and beam energy of 0.9-1.0 MeV. Although the operational range was not wide, the DT-mixed beam was found to be feasible in terms of the beam acceleration. These analyses also contribute to the study of the acceleration of other mixed ion beams such as impurity or heavy ions, which are useful techniques for diagnostic beams. [ABSTRACT FROM AUTHOR]

In order to realize negative ion sources and accelerators to be applicable to International Thermonuclear Experimental Reactor and JT-60 Super Advanced, a large cesium (Cs)-seeded negative ion source and a multi-aperture and multi-stage electric acceleration have been developed at Japan Atomic Energy Agency (JAEA). Long pulse production and acceleration of the negative ion beams have been independently carried out. The long pulse production of the high current beams has achieved 100 s at the beam current of 15 A by modifying the JT-60 negative ion source. The pulse duration time is increased three times longer than that before the modification. As for the acceleration, a pulse duration time has been also extended two orders of magnitudes from 0.4 s to 60 s. The developments of the negative ion source and acceleration at JAEA are well in progress towards the realization of the negative ion sources and accelerators for fusion applications. [ABSTRACT FROM AUTHOR]

Design techniques for the vacuum insulation have been developed in order to realize a reliable voltage holding capability of multi-aperture multi-grid (MAMuG) accelerators for fusion application. In this method, the nested multi-stage configuration of the MAMuG accelerator can be uniquely designed to satisfy the target voltage within given boundary conditions. The evaluation of the voltage holding capabilities of each acceleration stages was based on the previous experimental results about the area effect and the multi-aperture effect. Since the multi-grid effectwas found to be the extension of the area effect by the total facing area this time, the total voltage holding capability of the multi-stage can be estimated from that per single stage by assuming the stage with the highest electric field, the total facing area, and the total apertures. By applying these consideration, the analysis on the 3-stage MAMuG accelerator for JT-60SA agreed well with the past gap-scan experiments with an accuracy of less than 10% variation, which demonstrated the high reliability to design MAMuG accelerators and also multistage high voltage bushings. [ABSTRACT FROM AUTHOR]

To understand the physics of the cesium (Cs) recycling in the large Cs-seeded negative ion sources relevant to ITER and JT-60SA with ion extraction area of 45-60 cm × 110-120 cm, the time evolution of the negative ion profile was precisely measured in JT-60SA where the ion extraction area is longitudinally segmented into 5. The Cs was seeded from the oven at 180 °C to the ion source. After 1 g of Cs input, surface production of the negative ions appeared only in the central segment where a Cs nozzle was located. Up to 2 g of Cs, the negative ion profile was longitudinally expanded over full ion extraction area. The measured time evolution of the negative ion profile has the similar tendency of distribution of the Cs atoms that is calculated. From the results, it is suggested that Cs atom distribution is correlated with the formation of the negative ion profile. [ABSTRACT FROM AUTHOR]