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Notes: This paper describes novel rapid thermal annealing for GaAs wafers under vacuum conditions (VRTA) using a three-zone lamp power control method. The developed RTA technology eliminates generation of crystallographic slip lines and wafer deformation due to the convection effect caused by ambient gas. A three-zone lamp power control method produced excellent uniformity in the activated layer, presenting the best data ever attained by RTA. Also, numerical simulation demonstrates improved temperature uniformity achieved by a three-zone lamp power control method which reduces the edge radiation effect. Moreover, we have found that VRTA technology is particularly effective for annealing large-size GaAs wafers, which are more easily deformed or slip-lined than 2-in. wafers. We have applied VRTA to fabricating ion-implanted n+ contact regions for self-aligned 0.5-μm-gate doped-channel hetero-metal-insulator-semiconductor field-effect transistors with a lightly doped drain, and have obtained excellent Vt uniformity, σVt=19 mV, on a 2-in.-diam wafer. These features, together with a simple wafer-supporting method, using several quartz pins, cause the improved VRTA technology to provide high throughput and production yield for high-performance short-gate GaAs integrated circuits.

Notes: We demonstrate experimental results on the generation of sub-Poissonian photon fluxes emanating from an AlGaAs light-emitting diode, which manifest a wide-band (0–100 MHz) noise suppression below the standard quantum limit level despite low current density (∼38 A/cm2) operation at room temperature. The experimental noise power spectrum is well fitted in terms of the theoretical curve estimated with the quantum mechanical Langevin equations. © 1998 American Institute of Physics.

Notes: The mass distribution of neutral carbon clusters generated by a laser vaporization of graphite in He was safely determined by a single photon (10.5 eV) ionization technique. The resulting mass distribution was surprisingly different from those reported in previous articles. It was found that the carbon clusters generated under a moderate laser fluence condition (0.1–1 J/cm2) consists of mostly even-numbered monocyclic rings with the cluster sizes of n=10–18. The formation mechanism of such neutral carbon clusters upon laser irradiation is discussed. © 1997 American Institute of Physics.

Notes: The hypertensive effect of bromocriptine in young (6 week old) spontaneously hypertensive rats (SHR) was studied. Blood pressure and plasma norepinephrine level in bromocriptine-treated SHR were significantly lower than those in vehicle-treated SHR after 3 weeks of treatment (5 mg/kg per day, i.p.), while no significant decrease of blood pressure or plasma norepinephrine level was observed after 2 weeks of treatment. These results suggest the involvement of sympathetic nervous system inhibition in the hypotensive effect of bromocriptine in SHR.

Notes: 1. The present study examined the effect of heparin on nitric oxide (NO) formation and cyclic guanosine 3′, 5′-monophos-phate (cGMP) levels in cultured aortic endothelial cells (EC) from spontaneously hypertensive rats (SHR) and normoten-sive Wistar-Kyoto (WKY) rats.2. Bradykinin (BK), adenosine diphosphate (ADP), Ca2+ ionophore A23187 (Io) and endothelin-3 (ET-3) stimulated the production of NO and cGMP. No significant difference was observed in both NO and cGMP production in EC between WKY and SHR.3. Heparin enhanced BK-, ADP-, Io- and ET-3–stimulated NO and cGMP production. These enhancements by heparin in EC were significantly greater in SHR than in WKY.4. Both NO formation and cGMP production stimulated by the agonists and/or heparin were blocked in the presence of NG-monomethyl-L-arginine (LNMMA, 10-5mol/L).5. Increased sulphur level was observed on heparin-treated SHR EC surface compared with that on control SHR EC or on heparin-treated WKY EC surface.6. These results suggest that heparin promotes agonist-induced NO-cGMP response in cultured EC from SHR.

Notes: IgA nephropathy (IgAN) is known to commonly cause of end-stage renal failure in Japan. The glomerular lesions of IgAN have histological variations. The determination of prognosis and therapeutic strategy should be carefully done by experts because morphological information from renal biopsies using ordinary optical microscopy is usually qualitative and subjective. Moreover, the histological items for the evaluation of glomerular lesions seems to be unsatisfactory for expression of the disease condition of IgAN. The beneficial properties of scanning acoustic microscopy (SAM) include not only observation of microstructure but also quantitative measurement of acoustic propagation speed (APS), indicating the tissue elasticity. In the present study we compared the APS of glomeruli with the pathological scores that were determined by ordinary light microscopy. We used stocked human renal biopsy specimens diagnosed as IgAN (n = 12) and normal/minimal changes (n = 5). All samples were taken by renal biopsy in Kagawa Medical University Hospital during 1997–2000 under informed consent of the patients. The obtained renal tissue were immersed in 10% formalin and embedded in paraffin. A fixed specimen was consecutively cut into 4 μm slices. One of the deparaffinized 4 μm-specimens was directly utilized for SAM without any staining, and the others were stained with haematoxylin-eosin and Masson Trichrome for counting cell number and evaluation of collagen accumulation. For the measurement of glomerular APS, the sample line was set on the equator of the glomerulus and then scanning of the X–Z axis was carried out to obtain the interference fringes that were analysed with a computer imaging software in order to calculate the APS. In light microscopic study, pathological scores were evaluated semiquantitatively by two independent investigators who were unaware of the sample number. Glomerular lesions were scored into five grades and glomerular cell number was also counted in individual glomerulus. The computer-assisted imaging analyser Win ROOF (Mitani, Fukui, Japan) was also used for the determination of glomerular collagen content in specimens stained by Masson Trichrome. A two-dimensional image (C-mode scanning) of SAM enabled imaging of glomerulus in renal biopsy specimen compatible with findings of ordinary light microscopy without staining dye. The glomerular APS in IgAN was significantly higher than in normal/minimal changes. This alteration of glomerular APS in IgAN was positively correlated to both semiquantitative pathological scores and glomerular collagen content determined by light microscopy. However, the cell number of glomelurus did not change between IgAN and normal/minimal change. As a result, we conclude that the glomerular lesion, especially matrix expansion in IgAN, was comparable with the absolute value among specimens. Therefore, it is suggested that SAM method is a novel and useful technique for quantitative evaluation of glomerular lesion in IgAN.

Notes: 1. Endothelin (ET) B-type (ETB) receptor-mediated signal transduction was examined after stimulation with ET-3 in cultured aortic endothelial cells (EC) from spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats (8 weeks old).2. The EC from both rat strains expressed only ETB receptor mRNA. The receptor densities and affinities, which were non-selective for ET-1, -2, -3 and Sarafotoxin S6c, and mRNA expression were similar in WKY and SHR.3. The cytosolic Ca2+ level in the absence of extracellular Ca2+, inositol 1,4,5-trisphosphate levels, protein kinase C and phospholipase C activities in response to ET-3 were greater in SHR EC than in WKY EC.4. The 45Ca uptake in response to ET-3, which was blocked by Ni2+, was smaller in SHR EC than in WKY EC.5. The 6-keto-PGF1α production was augmented in SHR, though nitric oxide formation after stimulation with ET-3 was similar.6. These results suggest that ETB receptor-mediated phosphoinositide turnover signalling is augmented in SHR EC through postreceptor mechanism.

Notes: summary  Recently, various authors have proposed the interesting idea that occlusal force may be a principal factor in cervical lesions of the tooth. It is speculated that the lateral force in non-ideal mastication causes the tooth to bend and that the resulting tensile stress damages the enamel surface. In this study, we carried out stress analysis on the upper central incisor and the lower first molar using the plastic–elastic deformation theory with two-dimensional finite element method (FEM). The essential feature that the tensile yield strength is much smaller than the compressive one was taken into account. Our results suggested that oblique loading on the tooth stretches the enamel surface near the cemento-enamel junction and causes plastic deformation which eventually leads to the cervical lesion.