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AbstractNondestructive measurement of tritium (T) content in solid materials is important for safe and cost-effective disposal of contaminated wastes, and beta-ray induced X-ray spectrometry (BIXS) has been developed for this purpose. A common way to obtain depth profiles of T in solids using BIXS is to perform simulation of X-ray spectra for assumed depth profiles and find a profile giving the best agreement with observation. A detailed understanding of attenuation of low-energy X-rays (≤18.6 keV) by detector components such as a window material is required for interpretation of measured spectra and simulation. In this study, BIXS spectra of a tungsten reference sample with known T depth profile were measured using two different semiconductor detectors and simulated using the Monte Carlo simulation toolkit Geant4. In the low-energy region (<2 keV), the difference in internal structure resulted in a noticeable difference in the BIXS spectra. The disagreement between the measured and the simulated spectra was also significant at <2 keV. Nevertheless, at >2 keV, the BIXS spectra were insensitive to the internal structure of the detector, and the simulated spectra agreed well with the measured ones. The mechanism underlying the difference in the low-energy region was discussed.

AbstractUnderstanding and managing D retention in plasma facing components is essential for tritium safety in fusion reactors. Neutron irradiated and virgin low carbon arc cast (LCAC) Mo, as well as Mo foil samples with and without He pre-irradiation, were used to investigate D retention. D and He retention were investigated simultaneously in thermal desorption spectroscopy using a high resolution residual gas analyzer. Results show a significant increase in D retention with He pre-irradiation. Vacancies and vacancy clusters are found to retain D in LCAC samples, but neutron irradiated Mo retains more D in vacancy clusters.

AbstractThe effects of displacement damage, plasma exposure and heat loads on T retention in reduced-activation ferritic/martensitic (RAFM) steels were investigated by exposing the steels to DT gas at 473 K. Despite enormous change in surface morphology, T retention in the heat-loaded specimen was comparable with that in the unloaded specimen. The exposure to plasma resulted in a drastic increase in T retention at the surface and/or sub surface. However, the T trapped at the surface/subsurface was easily removed by maintaining the specimens in air at ~300 K. Formation of radiation-induced defects led to a significant increase in T retention, and T trapped in the defects was not removed at ~300 K. These observations suggest that displacement damages have the largest effects on T retention at ~473 K.

AbstractStainless steel exposed to gaseous tritium characteristically shows a firmly trapped fraction of tritium in the surface layer, which is not fully removable by water at ambient temperature. Prolonged thermal treatment of tritium-loaded specimens at <443 K causes substantial depletion of the bulk but almost no depletion of the surface layer. For complete removal of hydrogen isotopes from the bulk and the surface, temperatures exceeding 573 K are necessary. Upon chemical etching virtually all tritium trapped in the surface layer appears in the etching solution as tritiated water. Following removal of the layer by chemical etching, the tritium-rich layer reappears after months of aging at ambient temperature with nearly the original tritium activity. Comparison of chronic tritium release rates into liquid water before and after etching reveals that the surface layer only marginally influences the rate. X-ray photoelectron spectroscopy provides evidence that during prolonged aging the surface layer continues to grow while at the same time trapping a fraction of bulk tritium released at ambient temperature. Experimental results suggest different mechanisms of hydrogen uptake and release by the bulk and surface layers. Inference of tritium activity in the bulk of aged or heat-exposed stainless steel material from surface activity measurements may depart significantly from reality.

AbstractTritium retention in plasma facing materials is a primary issue for ITER and next step fusion devices, since it greatly affects its safety and operational schedule. In the ITER, carbon and tungsten are used as divertor materials. In the present study, co-deposited carbon film, tungsten and isotropic graphite were exposed to tritium gas, and then the amount of absorbed tritium was investigated. During the tritium exposure, the partial pressure of tritium gas was kept at 10 Pa. The sample temperature was kept a constant in the range from RT to 573 K. The amounts of absorbed tritium were evaluated by ²-ray-induced X-ray spectrometry (BIXS). The amounts of absorbed tritium in co-deposited carbon films were one or two orders of magnitude larger than that of polycrystalline tungsten and isotropic graphite. The amount of absorbed tritium for co-deposited carbon film with a high volume density (1.53 g/cm3) was several times larger than that of the film with a low volume density (1.13 g/cm3). The amount of absorbed tritium increased with the temperature. These results indicate that co-deposited carbon films can absorb much larger amount of tritium than tungsten and graphite, and carbon film density affects the amount of absorbed tritium.

AbstractA permeation measuring system with a nickel membrane of 30 μm thickness was installed near the mid plane of the spherical tokamak, QUEST. Hydrogen permeation through the membrane heated at fix temperatures (422 – 506 K) was measured during short pulse (< 1 s) and long pulse (1 hour) plasma discharges. After the membrane was heated to a required temperature, hydrogen plasma was discharged using a 2.45 GHz or 8.2 GHz RF system. Significant plasma-driven permeation was observed even for very short plasma discharges (e.g. 0.1s). Numerical calculations with the use of diffusion equation under recombination boundary conditions were conducted to simulate the transient permeation behavior. The numerical calculations were also used to estimate diffusion coefficient and recombination coefficients of membrane material. Temperature dependence of both the coefficients was explained by the Arrhenius law. A one hour long permeation curve was also numerically reproduced using the same set of parameters except an increasing recombination coefficient on the plasma side of the membrane.

AbstractThe behavior of hydrogen isotopes implanted into tungsten containing vacancies was simulated using a Monte Carlo technique. The correlations between the distribution of implanted deuterium and fluence, trap density and trap distribution were evaluated. Throughout the present study, qualitatively understandable results were obtained. In order to improve the precision of the model and obtain quantitatively reliable results, it is necessary to deal with the following subjects: (1) how to balance long-time irradiation processes with a rapid diffusion process, (2) how to prevent unrealistic accumulation of hydrogen, and (3) how to model the release of hydrogen forcibly loaded into a region where hydrogen densely exist already.

AbstractAn experimental study on tritium transfer in porous concrete materials for the tertiary tritium safety containment is performed to investigate; (i) how fast tritium is transferred through porous concrete walls coated with or without a hydrophobic paint, and (ii) how well the hydrophobic paint coating works as a film protecting against tritium migrating through concrete. The experiment is comparatively carried out using two types of cement-paste and mortar disks with or without two kinds of paints. The results obtained here are summarized as follows: (1) Tritium transfer can be correlated in terms of the effective tritium diffusivity of DT=1.2x10-11m2/s in porous cement. (2) Adsorbed or condensed liquid HTO itself is transferred only through pores in cement, and no tritium transfer path is present in non-porous sand. (3) Rates of tritium sorption and dissolution in cement and mortar coated with an epoxy-resin paint is correlated in terms of the diffusivity through the paint film of DT=1.0x10-16m2/s. (4) The epoxy paint works more effectively as an anti-tritium diffusion coating than the acrylic-silicon resin paint. (5) The hydrophobic property of the silicon resin paint is deteriorated with elongating the contact time with H2O.

Tritium measurement is indispensable for the fuel- processing systems of deuterium-tritium (DT)-fusion facilities. A new approach to detect tritium in regions deeper than the escape depth of beta-rays from tritium is being developed using an imaging plate (IP). The measurement principle of this approach is to observe bremsstrahlung X-rays induced by the tritium beta-rays. An IP made of europium-doped BaFBr(I), a photostimulated luminescence (PSL) material, is a two-dimensional radiation sensor. In the present study, the characteristics of this IP for measuring tritium by detecting bremsstrahlung X-rays, in particular a fading effect and the energy dependence of PSL sensitivities, are examined.

AbstractCompatibility of monolithic silicon carbide (SiC) with ternary lithium ceramics (Li1-xAlO2-y, Li2-xTiO3-y, Li2-xZrO3-yand Li4-xSiO4-y) under irradiation of neutrons at high temperatures was studied. Disk samples of SiC in contact with sintered ternary lithium ceramics were irradiated in High Flux Isotope Reactor (HFIR) at 800 °C to 5.9 displacements per atom (dpa). Chemical reactions of SiC as determined by appearance of the surface were relatively less significant for the systems of SiC/Li1-xAlO2-yand SiC/Li2-xTiO3-y, whereas some bonding likely due to chemical reaction between SiC and the lithium ceramics and broken samples were observed in the systems of SiC/Li2-xZrO3-yand SiC/Li4-xSiO4-y. The effect of lithium burnup due to the (n, α) nuclear reaction was also examined by using samples of lithium ceramics whose lithium ratio was hypo-stoichiometric in the fabrication process. More reaction products were observed on the surface of β-SiC in contact with Li1-xAlO2-yhaving the lower lithium ratio (Li/Al). It was considered that the formation of LiAl5O8phase due to lithium loss could deteriorate the compatibility of the SiC - Li1-xAlO2-ysystem.

AbstractJapan-US cooperation program TITAN (Tritium, Irradiation and Thermofluid for America and Nippon) started in April 2007 as 6-year project. This is the summary report at the midterm of the project. Historical overview of the Japan-US cooperation programs and direction of the TITAN project in its second half are presented in addition to the technical highlights.

AbstractCharacteristics of the tritium diffusion coefficient DTin V-4Cr-4Ti alloy, including a bending in the Arrhenius plot of DT, are examined. Based on a trap model, the possible trap sources and their binding energies for tritium in the alloy are evaluated using the experimental data of DTin pure V, which are measured with a tritium tracer method, and the literature data of protium diffusion in V-Ti and V-Cr alloys. The result of the evaluation suggests the presence of two trap sources in the alloy. The first would be attributed to a trap at each substitutional alloying atom which is likely to be Ti. The binding energy EBof 0.08 eV gives the best fit to the observed value of DTabove 300 K. The bending in the Arrhenius plot below 300 K is caused by a second trap site with a higher EB, and a lower concentration than those of each alloying atom. The trap is probably formed by the alloying atoms presence to neighboring Ti atoms. The contribution of Cr atom to the trap effect seems to be rather small in this alloy.

The authors performed linkage analysis in 39 families with autosomal recessive early-onset PD (AR-EOPD) negative for parkinand DJ-1mutations. Eight families including three Japanese, two Taiwanese, one Turkish, one Israeli, and one Philippine showed evidence of linkage with PARK6 with multipoint log of the odds (lod) score of 9.88 at D1S2732. The results indicate worldwide distribution of PARK6-linked parkinsonism.

Since many of antiarrhythmic drugs can act on variable ion channels of cardiac myocytes, these compounds may also play a role in the activity of similar ion channels expressed on the vascular smooth muscle cells. In contrast, some of these ion channels expressed on vasculature have different subtypes of the channels, indicating that antiarrhythmic drugs may differentially affect ion channels on cardiac myocytes and vascular smooth muscle cells. Therefore, it is crucial to note the effects of antiarrhythmic drugs on the regulation of vascular function. Previous studies using isolated blood vessels as well as cultured vascular smooth muscle cells indicate that antiarrhythmic drugs have some modulator effects on K+ channels expressed on the vascular smooth muscle cells. In addition, this modulation may be modified and dependent on the sort of stimuli, including those of pharmacological and pathophysiological. The K+ channel is one of the most important ion channels modulating vascular function to preserve the organ blood flow including that of the brain as well as the heart, and that several available K+ channel openers are expected to treat cardiovascular disorders, including hypertension, ischemic heart disease. Therefore, these results may provide us a hint to understand the advantage and / or disadvantage of these compounds on the v ascular function.

AbstractExperiment of D2permeation through Ni facing with purified Flibe is being carried out under the Japan-US joint research project (JUPITER-II). The experiment is proceeding in the following phases; (i) fabrication and assembly of a dual-probe permeation apparatus, (ii) a single-probe Ni/D2permeation experiment without Flibe, (iii) a dual-probe Ni/D2permeation experiment without Flibe, (iv) Flibe chemical purification by HF/H2gas bubbling, (v) physical purification by Flibe transport through a porous Ni filter, (vi) Ni/Flibe/D2permeation experiment, and (vii) Ni/Flibe/HT permeation experiment. The present paper describes results of the single and dual Ni/D2permeation experiments in detail.

Femtosecond transient reflectivity measurements were performed for Au(111) electrode/aqueous solution interfaces under electrochemical potential control. Electrode interfaces modified with and without a self-assembled monolayer of alkanethiols were studied in aqueous solutions of HClO4 and H2SO4. Dependence on electrochemical potential, interface modification, and kind of solute anions are observed concerning the transient reflectivity response in 3ps. For Au electrodes in an aqueous HClO4 solution, the rate of the initial relaxation at an unmodified interface, 6−10 ps^-1, decreased with the electrochemical potential at the potential range where a water dipole rearranged. The rate for alkanethiol-modified interfaces showed a tendency depending on the hydrocarbon chain length. A relative deposited energy from absorbed photon energy was estimated, indicating that interface modification with alkanethiols restricted energy dissipation from the interface. Our trial could contribute not only to develop a study of interaction between a substrate and adsorbed molecules in an ultrafast time scale but also to elucidate elementally processes of electrochemical reactions such as oxidation/reduction reactions at an electrode interface.

SummaryA new resin system, in which liquefied wood was reacted with various epoxy compounds, was previously developed. This paper reports the syntheses of two types of liquefied wood/epoxy resins with the ratio of liquefied wood to epoxy compounds (L/E ratio) of either 1/0.5 or 1/1. Furthermore, the viscoelastic properties obtained from the dynamic mechanical measurements of the cured resins and their adhesive bond properties measured as tensile shear strength are reported. The results from dynamic mechanical measurements indicated that the resins with a L/E ratio of 1/0.5 could be cured at 90°C, while the resins with L/E ratio of 1/1 were cured at 150°C. The resins cured with triethylene tetramine (TETA) at 150°C or 90°C had almost the same level of the normal adhesive shear strength as that of the commercial epoxy resin. The high level of adhesive shear strength of the resin cured at 150°C was maintained after the glued specimens were soaked in water at 60°C, while the share strength of the resins cured at 90°C was reduced by either the water soaking at 60°C or the cyclic boiling test.

Chick embryo fibroblasts and chorioallantoic membranes infected with fowlpox virus (FWPV) or pigeonpox virus (PPV) were examined by transmission and scanning electron microscopy. Immature virus particles were observed in finely granular areas, i.e. virus factories, of the cytoplasm. These particles had various forms depending on their stages of development. Many tubular structures were also seen in these regions. Mature virus particles with ellipsoidal or brick-shaped forms enclosing electrondense cores were detected throughout the cytoplasm. Notably, there was a high frequency of virus budding at the cell surface, but only occasional virus wrapping in the cytoplasm. Another remarkable feature of the infected cells was accumulation of many virions just beneath the plasma membrane, indicating that this phenomenon is closely related to virus budding. Based on the observed frequency of budding, this mechanism seems to be the predominant way for FWPV and PPV to exit the cell.
Keywords:fowlpox, pigeonpox, poxvirus, budding, TEM, SEM

Abstract: The diffusion behavior of hydrogen in the oxide films of zircaloy-4 specimens containing different size of Zr(Fe,Cr)2 precipitates was examined. In the case of the specimen containing fine precipitates, hydrogen diffused uniformly through the zirconium oxide phase. The diffusion coefficient was 2·10−21 m2·s−1 at room temperature and 6·10−19 m2·s−1 at 673 K. The transport rate of hydrogen in the oxide film of the specimen containing coarse precipitates was significantly higher than that of the specimen containing fine ones at both room temperature and 673 K.

Abstract: A survey is given of recent progress in measurements of photoabsorption, photoionization, and photodissociation cross-sections of molecules in the wavelength range of photons in the vacuum ultraviolet (VUV), where the optical oscillator-strengths of most molecules are predominantly distributed. Some remarks are presented on molecules in the condensed phase. Particular emphasis is placed on the current understanding of spectroscopy and dissociation dynamics of molecules in the superexcited states which are produced through the interaction of photons in this wavelength range. In the VUV range, most of the observed superexcited states are assigned to high-Rydberg states which are vibrationally (and/or rotationally), doubly, or inner-core excited, and converge to each of the ion states.

Objective and Design:To determine whether interleukin-13 (IL-13) possesses anti-inflammatory properties with respect to polymorphonuclear neutrophils (PMNs). Effects of IL-13 on production of the chemokine, macrophage inflammatory protein-1 alpha (MIP-1α), by PMNs were analyzed.¶Subjects:Human peripheral blood PMNs obtained from healthy volunteers.¶Methods:PMNs were stimulated by lipopolysaccharide (LPS) and/or IL-13 for selected periods of time, and MIP-1α expression was assessed by ELISA and Northern blot analysis.¶Results:IL-13 suppressed expression and production of PMN-derived MIP-1α mRNA and protein in a dose- and time-dependent manner. Inhibition of protein synthesis caused significant enhancement of MIP-1α mRNA expression. The inhibitory activity of IL-13 was abrogated, however, in the presence of cycloheximide, suggesting that IL-13's effect was via synthesis of de novo repressor protein(s).¶Conclusions:PMN-derived chemokines are regulated by both proinflammatory and immunomodulatory cytokines. The coordinated production of these substances is likely to be important in the orchestration of inflammatory and immune responses.

We have shown that there are at least 4 isotypes of the catalytic subunit of type 1 protein phosphatase (PP1), PP1α, PP1γ1, PP1γ2 and PP1δ by rat cDNA cloning. Among these, PP1γ2mRNA was found to be abundant in rat testis. To study the roles of PP1γ2 in rat spermatogenesis, we raised an antibody against a synthetic 21 mer peptide corresponding to the predicted amino acid sequence of the C-terminal region of the PP1γ2. The antibody interacted with a testicular protein of 39-kDa prepared from rats after puberty (25 days after birth). However, the antibody did not interact with proteins extracted from the immature testes or from other tissues examined. Indirect immunofluorescent staining of PP1γ2 of the seminiferous tubules from rats of various ages and co-staining with DNA showed that the protein is located in the nuclei of late spermatocytes and of early spermatids. We suggest that PP1γ2 plays some role in meiotic division during spermatogenesis.

cDNA clones for 4 rat protein phosphatase 1 (PP1) catalytic subunit isotypes, PP1α, PP1γ1, PP1γ2 and PP1δ, were isolated (K. Sasaki et al., Jpn. J. Cancer Res. 81, 1272-1280, 1990) . Antibodies were raised to determine the physiological functions of 4 isotypes. Among these isotypes, the PP1γ2 protein was detected specifically in rat testis (H. Shima et al., Adv. Prot. Phosphatases, vol. 7, in press) . On the other hand, PP1γ1, PP1δ and PP1α were detected as 36kDa, 37kDa and 38kDa proteins in several rat organs by immunoblot analysis. All three isotypes were found in both soluble and particulate fractions. PP1γ1 was predominant in the brain and PP1δ in the brain, lung and small intestine, but the levels of both were low in the liver and muscle. It became evident that PP1α was not a predominant isotype in any tissue examined.Copyright 1993, 1999 Academic Press

Abstract:  We present a first report of a CD7+ acute myelogenous leukemia patient who developed intracranial myeloblastomas. The patient was neurologically normal on physical examination at presentation. The peripheral leukocyte count was extremely high (203.6109/l). The blasts expressed CD7 and CD56 (neural cell adhesion molecule) in addition to CD13, CD33, CD34, and HLA-DR. The karyotype of bone marrow cells was normal. The patient was diagnosed as having acute myelogenous leukemia (AML, M1). Following a short period of complete remission, bone marrow relapse and meningeal leukemia occurred, and the patient died of respiratory failure. Autopsy revealed that blasts had invaded the subarachnoid space and cerebellum, and two myeloblastomas were found in the cerebellar hemisphere. Both CD7+ and CD56+ AML have been reported to have a high incidence of central nervous system involvement. CD7+ CD56+ AML calls for prophylaxis of central nervous system leukemia.