Diffusion of Water in Bentonite

Because of the low permeability and the high sorption coefficient, compacted sodium bentonite has been proposed as an effective backfill material in the repository of high-level radioactive waste. The only possible mechanism of nuclide transport in bentonite must be the diffusion. The diffusivity has been considered to have a close relationship with the retardation factor and the self-diffusivity of water. Then, we performed the experiments to determine the self-diffusivity of water in bentonite by using tritiated water as a tracer. The obtained self-diffusivity can be written as Da= (3.4 ± 0.2) × 10-6 [cm²/s] under the condition of temperature T= 25°C and compacted density of bentonite ρ= 2.7 [g/cm³]. It was revealed quantitatively that the self-diffusivity of water in bentonite is much smaller than that of free water (2.13 × 10-5 [cm²/s] at T= 25°C). Also discussed is the analysis of experimental results on the basis of a new solution derived for the diffusion in one dimensional finite zone

Evaluation of supercurrent distribution in High-TC superconductor by Scanning SQUID Microscopy

Scanning SQUID Microscope (SSM) is a powerful tool for observing small magnetic flux. It measures the z-component signal of flux density, but it is also available for observation of current distribution by inverting the Biot-Savart law. We report the two dimensional (2D) vector mapping of current distributions in high-TC superconducting YBa2Cu3O7−y (YBCO) thin films obtained by converting magnetic-field data measured by SSM. The current distribution contains those from both transport supercurrent and vortex current. The transport supercurrent is found to flow mainly along the edge of a stripline. The results are in good qualitative agreement with the calculated results based on simple London model. The YBCO films with an artificial grain boundary, i.e. Josephson boundary are also observed. The transport current seems to flows with avoiding the vortices, and an irregular vortex is observed at a point of grain boundary

Superstructure and Order-Disorder Transformation of Interstitial Oxygen in Hafnium

Crystal structure and phase transition in the hafnium-oxygen system containing 10-20 at% O have been studied by means of electron, neutron and X-ray diffraction and calorimetry as well. The oxygen atoms occupy the octahedral holes in h.c.p. metal lattice and two types of interstitial superstructures are found at the hypo- and hyper-stoichiometric composition HfO_ and HfO_ below 430℃. The lattice constants of the hexagonal supercells are respectively a=√, c=3c_0 and a=√, c=2c_0, where a_0～3.2A and c_0～5.1A are those of the metal lattice. The oxygen sublattices are described in terms of the stacking sequence of interstice layers parallel to the close-packed planes of the metal atoms, which varies continuously from A□B□C□…for HfO_ to A□B□…for HfO_. The concentration dependence of the ordered structures is interpreted in terms of strain ordering

Bone marrow edema and subchondral fracture in osteonecrosis of the femoral head: analysis with MRI and CT

Purpose: To study the relationship between bone marrow edema (BME) and subchondral fracture in osteonecrosis of the femoral head (ONFH), and to analyze MRI findings of subchondral fracture and correlate them with those of CT.Materials and Methods: Fifty seven hips in 38 patients with ONFH were studied retrospectively. Images were obtained with 1.5-T MRI unit and multidetector helical CT. Selected hips were divided into edema positive and edema negative groups. In each group presence or absence of subchondral fracture and/or collapse of femoral head was assessed, and the MR findings were compared with those of CT.Results: Thirty (52.6%) of 57 hips showed BME during the course of ONFH. In these edema positive group, 29 (96.7%) of 30 hips showed subchondral fracture and/or femoral head collapse, whereas only 7 (25.9%) of 27 hips in edema negative group showed subchondral fracture and/or FH collapse (P <0.0001). A low-signal intensity line on T1 and T2 weighted MR images and linear lucency on CT were the most common patterns of subchondral fracture.Conclusion: Our study showed significant relationship between BME and subchondral fracture/ femoral head collapse and supported the results of previous studies in considering BME as a marker for potential progression of osteonecrosis

Interactions between IL-32 and tumor necrosis factor alpha contribute to the exacerbation of immune-inflammatory diseases

IL-32 is a newly described cytokine in the human found to be an in vitro inducer of tumor necrosis factor alpha (TNFα). We examined the in vivo relationship between IL-32 and TNFα, and the pathologic role of IL-32 in the TNFα-related diseases – arthritis and colitis. We demonstrated by quantitative PCR assay that IL-32 mRNA was expressed in the lymphoid tissues, and in stimulated peripheral T cells, monocytes, and B cells. Activated T cells were important for IL-32 mRNA expression in monocytes and B cells. Interestingly, TNFα reciprocally induced IL-32 mRNA expression in T cells, monocyte-derived dendritic cells, and synovial fibroblasts. Moreover, IL-32 mRNA expression was prominent in the synovial tissues of rheumatoid arthritis patients, especially in synovial-infiltrated lymphocytes by in situ hybridization. To examine the in vivo relationship of IL-32 and TNFα, we prepared an overexpression model mouse of human IL-32β (BM-hIL-32) by bone marrow transplantation. Splenocytes of BM-hIL-32 mice showed increased expression and secretion of TNFα, IL-1β, and IL-6 especially in response to lipopolysaccharide stimulation. Moreover, serum TNFα concentration showed a clear increase in BM-hIL-32 mice. Cell-sorting analysis of splenocytes showed that the expression of TNFα was increased in resting F4/80(+ )macrophages, and the expression of TNFα, IL-1β and IL-6 was increased in lipopolysaccharide-stimulated F4/80(+ )macrophages and CD11c(+ )dendritic cells. In fact, BM-hIL-32 mice showed exacerbation of collagen-antibody-induced arthritis and trinitrobenzen sulfonic acid-induced colitis. In addition, the transfer of hIL-32β-producing CD4(+ )T cells significantly exacerbated collagen-induced arthritis, and a TNFα blockade cancelled the exacerbating effects of hIL-32β. We therefore conclude that IL-32 is closely associated with TNFα, and contributes to the exacerbation of TNFα-related inflammatory arthritis and colitis

Use of Short Inversion Time Inversion Recovery Imaging to Differentiate between Aplastic Anemia and Myelodysplastic Syndrome

The value of short inversion time inversion recovery (STIR) imaging in differentiating patients with aplastic anemia (AA) from those with myelodysplastic syndrome (MDS) was investigated. Thirty-nine patients with pancytopenia were diagnosed hematologically as having AA or MDS. These patients and 95 volunteers without hematologic disorders were then examined with STIR imaging. Hyperintense posterior pelvis was present in 25 of the 29 patients with MDS, including 17 of the 19 patients with refractory anemia. In contrast, high intensity of the posterior pelvis was absent in 8 of the AA 10 patients. High intensity of the femoral elements was present in 6 of the 8 patients with severe MDS and 3 of the 19 patients with refractory anemia. High intensity in the femoral elements was absent in all 10 AA patients. STIR imaging was useful in differentiating patients with AA from those with MDS

High-Resolution CT Evaluation of Ground-Glass Opacity In Diffuse Lung Disease

Ground-glass opacity of the lung is often demonstrated on high-resolution CT (HRCT) in various diffuse lung diseases. Ground-glass opacity generally results from minimal thickening of the alveolar interstitium or partial filling in the alveolar spaces. We classify diffuse infiltrative lung diseases into two clinical categories, namely, noninfectious and infectious lung disease. In noninfectious lung disease, although ground-glass opacity can be observed as an isolated finding, it is commonly observed to be combined with other findings such as centrilobular micronodules, interlobular septal thickening, and cystic air-spaces. These associated findings may be important for the differential diagnosis. Ground-glass opacity may also be seen as a consequence of increased capillary blood volume in redistribution of blood flow. This condition of hemodynamic origin is observed in chronic obstructive pulmonary disease, airway disease, and vascular lung disease. Although ground-glass opacity is a nonspecific finding, it can suggest a specific diagnosis in certain clinical circumstances or indicate a potentially treatable disease. Therefore, accurate recognition and differential diagnosis of ground-glass opacity are important

Pharmacological Comparison of Human Internal Mammary Artery and Radial Artery in Terms of Conduits for Revascularization

Internal mammary arteries (IMA) are routinely used for coronary artery bypass grafting (CABG), but can exhibit impairment of endothelium-dependent vascular relaxation. The use of radial artery (RA) grafts for CABG has been recently reintroduced. The long-term patency of these grafts may depend on the ability of these vessels to produce endotheliumderived nitric oxide (NO). We therefore sought to determine if the RA exhibits better endothelial function compared with IMA harvested from the same patient. Using the organ bath technique, vessels were preconstricted with the thromboxane A2 analogue (U46619) and exposed to increasing concentrations of either acetylcholine (ACh ), calcium ionophore A23187 (A23187), or nitroglycerin (NTG). We prepared the rubbed RA for comparison of between RA with and without endothelium on response to ACh relaxation. KCI and U46619 constricted RA (11.3ﾂｱ4.9g and 16.0ﾂｱ4.3g respectively) more than IMA(2.4ﾂｱ1.4g and 4.5ﾂｱ1.7 respectively). Both RA and IMA relaxed 100% of the preconstricted tension to NTG. ACh induced less relaxation in the IMA(28ﾂｱ24%) when compared with the RA(49ﾂｱ16%)(p<0.05). A23187 demonstrated relaxation in both the RA(86ﾂｱ14%)and IMA(76ﾂｱ18%), but there was no statistical difference. RA without endothelium showed same response to ACh as IMAs. Compared with the IMA, the RA has better ACh induced endothelium-dependent relaxation. This pathway mainly involves NO production which also inhibits the atherosclerotic process. Therefore, the RA may provide longer term graft patency than IMA

High concentrations of landiolol, a beta(1)-adrenoceptor antagonist, stimulate smooth muscle contraction of the rat trachea through the Rho-kinase pathway.

PURPOSE: Gradually progressing contraction of airway smooth muscle is suggested to be due to the Rho-kinase signaling pathway. In our preliminary study in rat tracheas, landiolol, a beta(1)-adrenoceptor antagonist, at high doses caused gradually progressing contraction, and this contraction reached a plateau after 20 min. Therefore, this study was carried out to clarify whether landiolol could stimulate the Rho-kinase pathway or the phosphatidylinositol (PI) response in the rat trachea. METHODS: Seventy-eight male Wistar rats weighing 250-350 g were used for the experiments. Their tracheas were cut into 3-mm-wide ring segments or 1-mm-wide slices. Measurements of isometric tension and [(3)H] inositol monophosphate (IP(1)) production were conducted, using these tracheal rings or slices. Data values are expressed as means +/- SD, and statistical significance (P < 0.05) was determined using analysis of variance (ANOVA). RESULTS: Landiolol (700 microM)-induced contraction was completely inhibited by fasudil at 30 microM, while the landiolol-induced contraction was not inhibited by 4-diphenylacetoxy-N-methyl-piperidine methobromide (4-DAMP), ketanserin, or nicardipine. Landiolol did not stimulate IP(1) production. CONCLUSION: These results suggest that high concentrations of landiolol could cause airway smooth muscle contraction through the Rho-kinase pathway, but not through the PI response coupled with muscarinic M(3) receptors, 5-HT receptors or the activation of L-type Ca(2+) channels

Truss structure tele-manipulation experiment using ETS-7

A robot experiment concept of space truss telemanipulation by National Aerospace Laboratory (NAL) is described in its flight model development. The experiment will be carried out on the Engineering Test Satellite No. 7 (ETS-7) using its robot arm. The satellite is scheduled to be launched in 1997 by National Space Development Agency of Japan (NASDA). The truss flight model is composed of deployable truss system and assemble truss joint. Those truss components will be manipulated by the ETS-7 robot arm using its small grapple fixture type-N (GPF-N), and the experimental task operation will be executed from the ground control station