Microscope observation of a self-standing film of porous silicon

A self-standing film (SSF) of porous silicon electrochemically isolated from the substrate has been observed under optical and electron microscopes. The SSF consists of two layers: the top layer, on the side from which anodization starts, cracks into cells exhibiting a fine porous structure: the bottom layer, on the side of isolation, shows a uniform and coarse porous structure. Under the optical microscope the film is found to expand upon wetting with methanol and to shrink back when it is dried. The change in the surface area amounts to about 10%, while any change in the thickness is undetectable. This expansion-shrinkage process can be repeated, but the film is occasionally cracked when it shrinks.     

Identification of chondromodulin I as a novel endothelial cell growth inhibitor. Purification and its localization in the avascular zone of epiphyseal cartilage

Cartilage is unique among tissues of mesenchymal origin in that it is resistant to vascular invasion due to an intrinsic angiogenic inhibitor. During endochondral bone formation, however, calcified cartilage formed in the center of the cartilaginous bone rudiment allows vascular invasion, which initiates the replacement of cartilage by bone. The transition of cartilage from the angioresistant to the angiogenic status thus plays a key role in bone formation. However, the molecular basis of this phenotypic transition of cartilage has been obscure. We report here purification of an endothelial cell growth inhibitor from a guanidine extract of bovine epiphyseal cartilage. The N-terminal amino acid sequence indicated that the inhibitor was identical to chondromodulin I (ChM-I), a cartilage-specific growth-modulating factor. Purified ChM-I inhibited DNA synthesis and proliferation of vascular endothelial cells as well as tube morphogenesis in vitro. Expression of ChM-I cDNA in COS7 cells indicated that mature ChM-I molecules were secreted from the cells after post-translational modifications and cleavage from the transmembrane precursor at the predicted processing signal. Recombinant ChM-I stimulated DNA synthesis and proteoglycan synthesis of cultured growth plate chondrocytes, but inhibited tube morphogenesis of endothelial cells. In situ hybridization and immunohistochemical studies indicated that ChM-I is specifically expressed in the avascular zone of cartilage in developing bone, but not present in calcifying cartilage. These results suggest a regulatory role of ChM-I in vascular invasion during endochondral bone formation.     

Endothelium-dependent relaxation of collateral microvessels after intramuscular gene transfer of vascular endothelial growth factor in a rat model of hindlimb ischemia

BACKGROUND: Recent investigations have demonstrated the ability of vascular endothelial growth factor (VEGF) to augment the development of collateral arteries in vivo. In vitro studies have suggested that the use of VEGF also improves the endothelium-dependent relaxation of collaterals at the microvascular level. The purpose of this study was to determine in vivo the extent to which vasomotor responses of collateral microvessels are altered after VEGF treatment. METHODS AND RESULTS:Ischemia was induced in the hindlimb of 35 rats by excision of the femoral artery. Immediately thereafter, 400 microg of a plasmid encoding VEGF or ss-galactosidase (control) was transfected into limb muscles. Four weeks later, synchrotron radiation microangiography, with a spatial resolution of 30 microm, was performed to document the reactivity of collateral microvessels. Administration of the endothelium-dependent vasodilator acetylcholine failed to induce dilation of collateral microvessels in control animals. By contrast, profound dilation of collaterals was observed after acetylcholine in VEGF-treated animals. This response was evident in vessels with a linear appearance but not in those with an undulating appearance. The resulting blood flow in the ischemic limb after administration of acetylcholine in the control animals was only 64.6+/-17.0% of that of the contralateral normal limb, whereas blood flow was augmented to 106.1+/-8.4% in VEGF-treated animals (P<0.05). CONCLUSIONS: These results demonstrate in vivo that the use of VEGF restores impaired vasomotor responses in some types of collateral microvessels, which may help to provide a basis for understanding the microcirculation after therapeutic angiogenesis with VEGF.     

Nonlinear optical properties and morphologies of vanadyl‐phthalocyanine thin films prepared on polyethylene‐terephthalate film

Vanadyl phthalocyanine (VOPc) crystal thin films were prepared on poly(ethylene terephthalate) (PET) film. The VOPc film prepared on PET substrate at 120 °C had Phase II. The third harmonic (TH) intensity of the VOPc film was measured by the marker fringe method. The third optical susceptibility (χ⁽³⁾) estimated from TH intensity is 3.5 × 10^?9 esu. The transition from Phase I to Phase II of the VOPc film was enhanced with corona charging. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(2): 36–43, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10022     

A fully integrated 0.13-/spl mu/m CMOS mixed-signal SoC for DVD player applications

This paper describes a fully integrated single-chip CMOS mixed-signal system on a chip (SoC) for DVD player applications. It integrates one digital signal processor (DSP), two 32-bit CPUs, three dedicated processing units, a partial response maximum likelihood (PRML) read channel with an analog front end (AFE), and many other subsystems on the same die. The AFE includes a fifth-order G/sub m/-C filter and attains over 66 dB C/N overall. PR(3,4,4,3) structure is employed in the PRML read channel. Owing to the PRML signal processing and the mixed-signal system level optimization in the PRML read channel, less than 10/sup -6/ of bit-error rate (BER) is obtained for the focus offset margins over /spl plusmn/0.5 /spl mu/m. This SoC is fabricated in 0.13-/spl mu/m one-poly six-Cu CMOS technology. It contains 24 million transistors in a 63.87 mm/sup 2/ die and consumes 1.5 W at 40 MSample/s data rate, which corresponds to DVD 1.5 times playback operation mode.     

Reduction in energy release rate for mode I fracture of a fibre with a cracked coating layer due to small-scale interfacial debonding

In order to predict the effect of small-scale interfacial debonding on the energy release rate at a crack tip for mode I fracture of a fibre with a cracked coating layer, an approximate calculation method has been presented. The relation of debonding length, thickness of the coating layer and ratio of elastic modulus of the coating layer to that of the fibre, to the energy release rate of the fibre was calculated for some examples. It was demonstrated that small-scale debonding reduces the energy release rate and, therefore, effectively prevents reduction in fibre strength.     

Chemical modification of amino acid residues in glycerinated Vorticella stalk and Ca(2+)-induced contractility

The effects of sodium dichloroisocyanurate (NaDCC) and Solprogel (Laboratorios Inibsa, S.A., Barcelona, Spain), a compound that contains NaDCC plus a biodegradable polymer of acrylic acid, on the activity of DNA polymerase (DNA-P) associated with hepatitis B virus in serum were evaluated. DNA-P positive and negative pools of human serum samples were used as positive and negative stock virus. Inhibition of DNA-P activity by NaDCC and the commercial product was found to be concentration-dependent. Two minutes exposure to the minimum effective concentration of NaDCC (1000 ppm available chlorine) or Solprogel 16% (960 ppm available chlorine) totally inhibited DNA-P activity.     

The prevalence rate and etiology of severe motor and intellectual disabilities syndrome in Okinawa

We studied sixty-three children of severe motor and intellectual disabilities syndrome aged between 3 and 5 years, who live in Okinawa. Severe motor and intellectual disabilities syndrome were defined as those who belong to classes 1 approximately 4 of Ohshima's classification (incapable of walking with IQs not more than 35). The prevalence rate was about 1.12/1,000 live births. Forty-four% of the total children belonged to class 1 of Ohshima's classification (bedridden and IQs less than 20). The factors were: congenital 31.7%, perinatal 38.1%, postnatal 14.3%, and unknown 15.9%. The perinatal factor was still relatively high as compared with the others.     

Controlled beam dry etching of InP by using Br2-N2 Gas

Indium phosphide dry etching is carried out using a reactive beam extracted from a Br₂-N₂ gas discharge plasma. Keeping the N₂ gas pressure constant at 0.23 mTorr, the Br₂ gas pressure was varied from 0 to 0.1 mTorr and the sample temperature was varied from 40 to 200°C. The etched shapes and etching rates are investigated in terms of the etching beam composition. Two distinct types of etching mechanisms come into play depending on the Br₂ gas pressure. Smooth vertical side walls and a temperature independent etching rate can be obtained at a Br₂ gas pressure of 0.04 mTorr or less and a temperature above 100°C, where the etching is induced by the ambient Br₂ gas species and N₂ beam. Undercut etching with a temperature dependent etching rate is seen at a Br₂ gas pressure of 0.07 mTorr or higher, where the etching beam contains both N₂ and Br₂ gas species. Neutralized Br species generated by the discharge of the Br₂ gas are shown to form the undercut. A waveguide corner mirror with a loss of less than 1 dB is made by using an etching beam with no neutralized Br species.