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Abstract: The tritium release model to represent the release behavior of bred tritium from solid breeder materials has been developed by the blanket group of Kyushu University. It has been found that water is released to the purge gas from solid breeder materials and that this water affects the tritium release behavior. In this study, the amount of surface water released from Li4SiO4 is quantified by the experiment. In addition, the tritium release behavior from Li4SiO4 are estimated based on the tritium release model using parameters obtained in our studies under conditions of commercial reactor operation and ITER test blanket module operation. The effect of the surface water on tritium release behavior is discussed from the obtained results. Moreover, the tritium inventory of Li4SiO4 is discussed based on calculation under the unsteady state condition. Further, the effects of grain size and temperature on distribution of tritium inventory under the steady state condition are evaluated, and the optimal grain size is discussed from the view point of tritium release from Li4SiO4. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) derived from inducible nitric oxide synthase (iNOS) plays an important role in host defense, as well as in inflammation-induced tissue lesions. Here we evaluated the role of NO in bone loss in bacterial infection-induced apical periodontitis by using iNOS-deficient mice (iNOS-/-). The iNOS-/- mice developed greater inflammatory cell recruitment and osteolytic lesions than WT mice. Moreover, tartrate-resistant acid-phosphatase-positive (TRAP+) osteoclasts were significantly more numerous in iNOS-/- mice. Furthermore, the increased bone resorption in iNOS-/- mice also correlated with the increased expression of receptor activator NF-kappaB (RANK), stromal-cell-derived factor- 1a (SDF-1α/CXCL12), and reduced expression of osteoprotegerin (OPG). These results show that NO deficiency was associated with an imbalance of bone-resorption-modulating factors, leading to severe infection-stimulated bone loss. [ABSTRACT FROM AUTHOR]

The inflammatory oral diseases are characterized by the persistent migration of polymorphonuclear leukocytes, monocytes, lymphocytes, plasma and mast cells, and osteoblasts and osteoclasts. In the last decade, there has been a great interest in the mediators responsible for the selective recruitment and activation of these cell types at inflammatory sites. Of these mediators, the chemokines have received particular attention in recent years. Chemokine messages are decoded by specific receptors that initiate signal transduction events, leading to a multitude of cellular responses, including chemotaxis and activation of inflammatory and bone cells. However, little is known about their role in the pathogenesis of inflammatory oral diseases. The purpose of this review is to summarize the findings regarding the role of chemokines in periapical and periodontal tissue inflammation, and the integration, into experimental models, of the information about the role of chemokines in human diseases. [ABSTRACT FROM AUTHOR]

Profiles of hydrogen molar fraction and temperature in a long ZrV1.9Fe0.1 alloy particle bed with a small diameter were determined experimentally and analytically as a basic study of chemical heat pumps operated at higher temperature. Since the alloy bed absorbed hydrogen even at 873 K and generated heat, the alloy was considered a suitable material for heat pump or hydrogen storage at higher temperature. Experimental profiles of both hydrogen molar fraction at the bed outlet and temperature inside the bed agreed with analytical solutions to heat and mass-transfer equations. The analytical solutions were obtained under the conditions where constant-pattern approximation could be applied to the temperature and concentration profiles propagating in a bed with the same velocity. Properties relating with heat transfer such as a heat capacity, enthalpy change of hydrogen absorption and a heat-transfer coefficient between a wall and particles were correlated to two dimensionless parameters, α and β. [Copyright &y& Elsevier]

Profiles of hydrogen molar fraction and temperature in a long ZrV1.9Fe0.1 alloy particle bed with a small diameter were determined experimentally and analytically as a basic study of chemical heat pumps operated at higher temperature. Since the alloy bed absorbed hydrogen even at 873 K and generated heat, the alloy was considered a suitable material for heat pump or hydrogen storage at higher temperature. Experimental profiles of both hydrogen molar fraction at the bed outlet and temperature inside the bed agreed with analytical solutions to heat and mass transfer equations. The analytical solutions were obtained under the conditions where constant-pattern approximation could be applied to the temperature and concentration profiles propagating in a bed with the same velocity. Properties relating with heat transfer such as a heat capacity, enthalpy change of hydrogen absorption and a heat-transfer coefficient between a wall and particles were correlated to two dimensionless parameters, α and β. [Copyright &y& Elsevier]

Rates of CH4 cracking on a Ni/SiO2 composite catalyst in a flow-through system were determined as a function of a flow rate, the CH4 concentration in carrier, temperature and the amount of carbon deposits. The CH4 decomposition reaction was of the first-order, and its rate constant was independent of the flow rate and the inlet CH4 concentration. Values of the steady-state decomposition rate constant were correlated to kdecomp=3.09×101exp(-29.5[kJ/mol]/RgT) [s-1]. The overall decomposition rate gradually decreased with an increase in the amount of carbon deposits in the catalyst bed. The history of the CH4 decomposition was discussed in terms of an increase in the linear velocity through the bed and an increase in interference with catalytic performance on Ni. Regeneration of the catalyst was compared under two purge gas conditions between H2 and O2. It was found that the H2 purge was more efficient. [Copyright &y& Elsevier]

Pressure–composition isotherms of the ZrV1.9Fe0.1–hydrogen system were determined by a constant volume method and were correlated to an empirical van’t Hoff equation. The enthalpy change of hydrogen absorption was correlated to a function of the hydrogen-to-alloy atomic molar ratio. The entropy change was independent of it. Heat and mass transfer process in a concentric-annular-tube bed packed with the ZrV1.9Fe0.1 particles was studied experimentally and numerically as a basic study of hydrogen storage at elevated temperature. A one-dimensional concentric-annular-tube bed was charged with hydrogen. The experimental profiles of hydrogen partial pressure and temperature were compared with numerical simulation calculated by the pressure–composition isotherm, a hydrogenating rate equation and two balance equations of hydrogen and heat. Another simplified analysis using three dimensionless lump parameters succeeded in estimating temperature profiles in the hydrogen-absorbing-alloy bed more easily. The simulation was able to make it better to understand contributions of experimental parameters such as the flow rate, surrounding temperature and other physical properties. [Copyright &y& Elsevier]

Summary The laminin α2‐chain is a component of merosin, a member of the laminin family molecules, which is mainly expressed in the basement membranes of striated muscle. It is known that laminin α2 gene (lama2) null mutant mice (dy3k/dy3k) exhibit congenital muscular dystrophy (CMD). Because the laminin α2‐chain is also expressed in the thymus, the role of merosin in the thymus was examined. In association with the onset of muscular dystrophy, CD4+ CD8+ double‐positive (DP) thymocytes disappear by apoptotic cell death, while CD4+ CD8– or CD4– CD8+ thymocytes remain. In order to study the mechanisms leading to the selective death of DP cells in the absence of merosin, the role of the interaction between very late activation antigen‐6 (VLA‐6), a candidate merosin ligand in the thymus, and merosin was examined. The in vitro survival of thymocytes from normal mice was maintained by the addition of either anti‐VLA‐6 monoclonal antibodies (mAbs) or merosin. Furthermore, when the normal thymocytes were cultured on thymic epithelial cell lines, viable DP cell recoveries on wild‐type epithelial cells were better than on cells from null mutant mice. The results suggest that DP cells are more sensitive to an uncharacterized apoptotic death signal, and that survival is supported by the interaction between VLA‐6 and merosin. [ABSTRACT FROM AUTHOR]

The mutagen glyoxal was reacted with DNA or deoxynucleosides under physiological conditions (pH 7.4, 37°C) in vitro and the products were analyzed by HPLC coupled with a photodiode array UV detector. The efficient formation of a cyclic glyoxal-dG adduct (dG+) was observed in DNA, as well as with dG. The monomeric dG+ was gradually decomposed to dG at pH 7.4 and 37°C (t1/2 14.8 h). However, the dG+ formed in single- and double-stranded DNA was rather stable under physiological conditions and the half-lives were 19 and 40 times longer respectively than that of the monomer (t1/2 285 and 595 h respectively). By reaction of glyoxal with deoxycytidine (dC), the deamination products of deoxyuridine and 5-hydroxyacetyl-dC (dC+) were formed. Under the same conditions, 5-methyl-dC was deaminated to dT at a higher rate. Deoxyuridine was also formed in DNA by glyoxal treatment. When glyoxal was reacted with various combinations of deoxynucleosides for a prolonged period, dG-glyoxal-dC (GgC), dG-glyoxal-dA (GgA), dG-glyoxal-dG (GgG) and dC-glyoxal-dC (CgC) cross-links were detected, although structures were not assigned unequivocally. Among these, the former two, the GC and GA cross-links, were detected in glyoxal-treated DNA. The yields of these products in DNA were in the following order; dG+ > dU > GgA > GgC > dC+. These DNA modifications may be relevant to glyoxal-induced mutations at GC pairs. [ABSTRACT FROM PUBLISHER]