No abstract

Integrins are a superfamily of cell surface glycoproteins that promote cellular adhesion. The interaction of integrins with extracellular matrices such as fibronectin and vitronectin has been shown to be mediated through an arginine-glycine-aspartic acid (RGD) sequence within adhesive proteins. Triflavin, a 7.5-kDa cysteine-rich polypeptide purified from Trimeresurus flavoviridis snake venom, belongs to a family of RGD-containing peptides, termed disintegrins. Disintegrins have been isolated from the venom of various vipers and have been shown to be potent inhibitors of platelet aggregation. In this study, we found that human hepatoma cell adhesion to immobilized matrix proteins (i.e. fibronectin, collagen, laminin, and vitronectin) was differentially affected by various anti-integrin monoclonal antibodies (mAbs) (i.e., alpha3beta1, alpha5beta1, alpha6beta1, and alpha v beta3) as well as by the peptide GRGDS. Indirect flow cytometric analysis of hepatoma cells with anti-integrin mAbs demonstrated that alpha6beta1 was uniformly expressed at a high density, while alpha3beta1, and alpha5beta1 were moderately expressed and alpha v beta3 was expressed in small amounts on hepatoma cells, consistent with the results obtained from immunofluorescence microscopic analysis. When immobilized on plastic wells, triflavin promoted hepatoma cell attachment; this cell attachment was inhibited by either GRGDS or mAbs against integrins alpha3beta1, alpha5beta1 and alpha v beta3). In addition, the binding of FITC-conjugated triflavin to hepatoma cells was inhibited by GRGDS, anti-alpha3beta1, antialpha5beta1, and anti-alpha v beta3 mAbs. Among these mAbs, anti-alpha5beta1 exerted the most pronounced inhibitory effect (>70%) on the binding of triflavin to hepatoma cells. Taken together, these results suggest that triflavin binds via its RGD sequence to multiple integrin receptors (i.e., alpha5beta1, alpha3beta1, and alpha v beta3) expressed on the surface of hepatoma cells, resulting in inhibition of hepatoma cell adhesion to extracellular matrices (i.e., fibronectin and vitronectin).

Electronic speckle pattern interferometry (ESPI) is a powerful tool for the full eld, noncontact, and real-time measurement method of surface displacements for deformed bodies. As compared with the conventional lm recording and optical reconstruction procedures used for holographic interferometry, the interferometric fringes of ESPI are produced instantlyby a video recording system. In this study, the amplitude uctuation ESPI (AF-ESPI) optical system is used for measuring the resonant frequencies and mode shapes of vibrating composite plates. By makinguse of the resonant frequencies for free plates obtainedexperimentally,an inverse evaluationfor the material constants is developed using the Rayleigh-Ritz technique and the Simplex method for function minimization. Finally, nite element calculation is used to construct the mode shapes from the obtained material constants by inverse evaluation, and the results are compared with the experimental observations. The experimental method based on optical AF-ESPI setup and the inverse algorithms proposed might become a reliable and self-consistent methodology for evaluating material constants of composite plates. Nomenclature A= vibration amplitude D i j = laminate bending stiffness I A = object light intensity I B = reference light intensity w = transverse displacement µ = angle between object light and observation directioņ = wavelength of laser ½ = mass density ¿ = charge-coupled device refreshing time Á = phase difference between object and reference light ! = vibration frequency

Indium phosphide, a direct gap semiconductor with a room temperature energy gap of 1.35 eV, is a promising photovoltaic material for thin film devices. Thin films of indium phosphide have been deposited on tungsten‐coated graphite substrates by the reaction of indium, hydrogen chloride, and phosphine in a gas flow system. Without intentional doping, the deposited films are n‐type with a carrier concentration of about 1017 cm−3. Schottky barriers prepared from these films have been found to exhibit low rectification ratios, high dark currents, and poor photovoltaic response due to the shunting effects of grain boundaries. The grain boundary effects can be partially reduced by heat‐treatment in an ammonia atmosphere, converting the surface of grains into indium nitride. The formation of indium nitride has been verified by Auger electron spectroscopy and x‐ray photoelectron spectroscopy.