Dynamic contrast-enhanced MR imaging of the entire breast with spectral-selective inversion fast three dimensional sequence

Dynamic contrast-enhanced images with high spatial and temporal resolutions were acquired with a fast 3D spoiled gradient echo (SPGR) sequence using spectral selective inversion recovery (IR) pulse. Five healthy volunteers and 12 patients with 14 pathologically proven breast lesions were studied. Fat suppressed volume image data covering the entire breast were obtained with a sufficient spatial resolution (0.9×1.5×3.0 mm³) and an imaging time of 57 s. By using the criteria including peripheral enhancement and presence of spiculation, sensitivity, specificity, and accuracy in detecting malignant lesions were 88.9, 80.0 and 85.%, respectively. Although the C/N and S/N ratios were approximately 30% less than those of the conventional fat suppressed 3D technique, fast 3D SPGR imaging with spectral IR method demonstrated sufficient image quality for both time intensity analysis and morphological evaluation of the breast lesions with a data acquisition time less than half of the conventional method. This technique can substantially improve spatial and temporal resolutions of dynamic MR images of the breast and will be useful in evaluating malignant and benign breast lesions.     

Strain Hardening in Superplastic Codoped Yttria-Stabilized Tetragonal-Zirconia Polycrystals

The superplastic characteristics of 3-mol%-yttria-stabilized tetragonal-zirconia polycrystals (3Y-TZP) were drastically improved by the combined addition of germanium oxide and other oxides (titanium, magnesium, and calcium), resulting in up to 1000% elongation under optimum conditions. Extensive work hardening of the codoped compositions for temperatures >1400°C was observed. Dynamic grain growth was not a sufficient mechanism to explain this anomalous high strain hardening. The appearance of a cubic phase that caused abnormal grain growth during testing may have resulted in increased flow stress, which resulted in exaggerated work hardening.     

ULVAC research and development of Cat-CVD applications

This paper reports the feasibility for industrial implementation of Cat-CVD (Hot-Wire CVD) technology. Some application examples are shown, and their features and problems are described. Cat-CVD is a unique technology which has a lot of possibilities. Some of them will be commercialized in the near future, but the others need a breakthrough for mass production.     

Tetrahedral-shaped recess (111)A facet channel AlGaAs/InGaAsheterojunction field-effect transistor with an InGaAs floating quantumdot gate

A transistor and memory operation of a new AlGaAs/InGaAs heterojunction field-effect transistor (HFET) in a tetrahedral-shaped recess (TSR) on the (111)B GaAs substrate was investigated at a temperature up to 120 K. The TSR-FET memory has a channel on the (111)A side surfaces of the recess and a single floating quantum dot (QD) gate at the bottom. Owing to the particular shape of the TSR structure, the charge in the floating QD gate can effectively modulate the channel current. We found a clear hysteresis in the current-voltage (I-V) characteristics with an abrupt increase and decrease in the current at the subthreshold gate bias region. Random telegraph signals with a constant amplitude of about 70 nA were also observed in the memory retention characteristics. These phenomena were considered to be attributed to the current modulation by hole charging/discharging in the QD     

Mechanisms of Texture Development in Bismuth Layer-Structured Ferroelectrics Prepared by Templated Grain Growth

The mechanism for texture development in bismuth layer-structured ferroelectrics prepared by the templated grain growth method was examined using template and matrix grains with different chemical compositions. The template particles used were platelike Bi₄Ti₃O₁₂ and Ba₆Ti₁₇O₄₀ for SrBi₄Ti₄O₁₅-matrix composites and platelike Ba₆Ti₁₇O₄₀ and Sr₃Ti₂O₇ for BaBi₄Ti₄O₁₅-matrix. The 001-texture developed in all composites examined. The origins of texture development were the growth of matrix grains to be platelike and the formation of face-to-face contact between the template and matrix grains and also between matrix grains.     

Thermodynamic Analysis of the Cubic–Tetragonal Phase Equilibria in the System ZrO2–YO1.5

The cubic-tetragonal (c-t) phase equilibria in the system ZrO₂-YO_1.5 are thermodynamically analyzed from Landau's phenomenological theory. The calculated c-t two-phase field is depicted as a miscibility gap with a sharp maximum and the spinodal region as originally predicted by Hillert and Sakuma. However, the observed c-t two-phase field and the spinodal region are better described by the present model. In addition, this model can be used to discuss the nature of the c-t diffusionless transformation from the order parameter in contrast with the original model. The predicted change in the tetragonality of t-ZrO₂ with YO_1.5 content is slightly different from that in the c/a axial ratio estimated from X-ray diffraction analysis. The displacement of cations and anions may not take place simultaneously during the c-t transformation.     

Isolation and characterization of the human X-arrestin gene

In previous publications we have discussed the stabilization mechanism of hydration forces as applied to the development of latex agglutination tests. We describe here how we have obtained stable and reactive IgG-latex conjugates in a high-ionic-strength reaction buffer. To this end we have made agglutination tests with polystyrene beads sensitized with IgG, measuring the immunoaggregation reaction with human C-reactive protein in a stopped-flow nephelometer. The results are compared to those obtained with a F(ab')2-latex conjugate with similar antibody molecule coverage. Adsorption isotherms of F(ab')2 and IgG on latex at pH 7.2 were obtained to study the affinity of these antibodies for the surface. The results of the electrokinetic characterization of the antibody-latex conjugates agree satisfactorily with those obtained from stability studies. This research throws light upon the use of hydration forces as a new approach to stabilizing immunoassay reagents that are colloidally unstable in physiological reaction buffers.     

Regional variations of the cytokeratin expression along the guinea pig cochlear turn]

Expression of cytokeratin (Ck) proteins in the guinea pig cochlea was examined using a recently developed immunohistochemical method for celloidin section. This method has allowed us to observe a whole cochlea with excellent morphological preservation in a visual field under the light microscope. Anti-Ck antibodies FIL-7 (AE-1, Signet Lab.) and NCL-CK19 (Novocastra Lab.) stained all supporting cells of the organ of Corti, in which pillar cells, Deiters' cells, Hensen's cells, and Boettcher's cells showed a strong reaction. The histochemical labeling of pillar and Deiter's cells showed a gradual increment from the base to the apex. The immunohistochemically stained area in Hensen's cells increased toward the apex, which was attributed mainly to the increase in both the number and size of Hensen's cells from the base to the apex. In an electron-microscopic examination, changes in histochemical labeling of Hensen's cells did not appear from the base to the apex. Close examination revealed that reaction precipitates were distributed along a filament structure which seemed to correspond to the cytokeratin filaments. These results suggest that the Ck filaments give elasticity and flexibility to the supporting cells in the organ of Corti and provide mechanical strength to the organ of Corti at the upper turns, which vibrate with larger amplitudes, and that the Ck filaments in the supporting cell must be of considerable importance as a tuning mechanism. Immunohistochemical labeling for Ck was also observed in the spiral prominence cells, outer sulcus cells, interdental cells, and Reissner's membrane. The positively stained area in the outer sulcus increased from the apex to the base.     

Responses of human glioblastoma cells to human natural tumor necrosis factor-alpha: susceptibility, mechanism of resistance and cytokine production studies

Responses and susceptibility of 14 human glioblastoma cell lines to human natural tumor necrosis factor-alpha (TNF) were studied in vitro. Susceptibility of glioblastoma cells to TNF varied in experimental conditions applied. Most of glioblastoma cell lines were resistant to cytotoxic activity of TNF in a MTT assay at concentrations below 16 U/ml for 72 h exposure. However, TNF at higher dose, in prolonged exposure and against low density of target cells was antiproliferative for certain glioblastoma cultures. TNF exposure at 10 U/ml for 48 h suppressed DNA synthesis in 9 of 14 glioblastoma cultures, but increased in 3 cultures. In addition, colony forming assay showed anti-clonogenic activity of TNF in 5 of 6 glioblastoma cell lines tested. In spite of their low susceptibility to TNF, glioblastoma cells well responded to TNF stimulation at low dose (10 U/ml) for a short period in the absence of cell damage. Productions of Interleukin-6 (IL-6), IL-8-like activity, granulocyte-macrophage colony stimulating factor (GM-CSF), prostaglandin E2 (PGE2) and manganous superoxide dismutase (Mn-SOD) were enhanced or induced by the low-dose TNF stimulation. Mn-SOD, a protein protective against oxidative cell damage, was well induced in time- and dose-dependent manner, however did not correlate with TNF resistance. Whereas the levels of PGE2 in TNF-susceptible cell lines, H-4 and SF-188, were higher than those of other lines. In conclusion, most of glioblastoma cells are resistant to TNF cytotoxic effects, but highly responsive to TNF stimulation. Its effect on glioblastoma cells appears to modulate cell differentiation rather than to kill the cells.