Decorin activates the epidermal growth factor receptor and elevates cytosolic Ca2+ in A431 carcinoma cells

Several independent lines of evidence have implicated decorin, a small leucine-rich proteoglycan, in the inhibition of cell proliferation. However, the mechanism by which decorin mediates its effect on cell proliferation is unclear. Here we report, for the first time, decorin-mediated increases in intracellular Ca2+ levels of single A431 cells. The effects of decorin persisted in the absence of extracellular Ca2+ but were blocked by AG1478, an epidermal growth factor (EGF)-specific tyrosine kinase inhibitor, and by down-regulation of the EGF receptor. The effects of decorin were not mimicked by the structurally homologous protein, biglycan. Our results indicate a novel action of decorin on the EGF receptor, which results in mobilization of intracellular Ca2+ providing a possible mechanism by which decorin causes growth suppression.     

High performance VLSI architecture for division and square root

A novel high performance bit parallel architecture to perform square root and division is proposed. Relevant VLSI design issues have been addressed. By employing redundant arithmetic and a semisystolic schedule, the throughput has been made independent of the size of the array.<>     

Guarino Guarini and his Grand Philosophy of Sapientia and Mathematics

This paper proposes that there is a wide and important wealth to the philosophy and art of Guarino Guarini, and one of the keys to these matters lies in the structure and content of his Architettura civile, his posthumously-published treatise on architecture. Guarini was an important mathematician in the development of calculus, and his fame is not just that of an architect, perhaps the most learned that Europe has ever thrown up.     

In situ ATR-IR spectroscopic and electron microscopic analyses of settlement secretions of Undaria pinnatifida kelp spores

Knowledge about the settlement of marine organisms on substrates is important for the development of environmentally benign new methods for control of marine biofouling. The adhesion to substrates by spores of Undaria pinnatifida, a kelp species that is invasive to several countries, was studied by scanning electron and transmission electron microscopies (SEM/TEM) as well as by in situ attenuated total reflection infrared (ATR-IR) spectroscopy. The IR spectra showed that adhesive secretion began approximately 15 min after initial settlement and that the adhesive bulk material contained protein and anionic polysaccharides. Energy dispersive X-ray microanalysis of the adhesive identified sulphur and phosphorus as well as calcium and magnesium ions, which facilitate the gelation of the anionic polysaccharides in the sea water. The adhesive may be secreted from Golgi bodies in the spore, which were imaged by TEM of spore thin sections. Additionally, an in situ settlement study on TiO₂ particle film by ATR-IR spectroscopy revealed the presence of phosphorylated moieties directly binding the substrate. The presence of anionic groups dominating the adhesive suggests that inhibition of spore adhesion will be favoured by negatively charged surfaces.     

The reaction of hf with polyacetylene

Anhydrous HF reacts with polyacetylene to produce a material with high conductivity. Infrared spectra of lightly doped samples show bands characteristic of a delocalized positive charge along the polymer chain. Upon heavier doping, conductivities of 1⫁−10 (ohm-cm)⁻¹ are measured. Addition of ammonia produces an ammonium ion on the chain, and destroys the conductivity of the material. A discussion of the doping mechanism and related reactions is given.     

The synthesis of the first stage graphite salt C8+AsF6− and its relationship to the first stage graphite/AsF5 intercalate

Oxidation of graphite with excess O₂⁺AsF₆^?, in suspension in SO₂C1F, produces the blue first-stage graphite salt of composition C₈AsF₆, which X-ray single crystal photographs show is hexagonal with a = 4.92(2), c = 8.10(2), $\text{V}\text{= 170}\text{A}\text{?}{}^3$. The blue first-stage material of approximate composition C₁₀AsF₅ obtained from graphite and AsF₅ has a related pseudo cell. Arsenic X-ray absorption-edge spectra show that C₈AsF₆ contains AsF₆^? alone, and that the graphite/AsF₅ intercalte contains AsF₆^? and AsF₃ in accord with the AsF₅ reduction:

$\text{3 AsF}{}_5\text{+ 2 e}{}^{\mathrm{?}}\text{→ 2 AsF}{}_6{}^{\mathrm{?}}\text{+ AsF}{}_3$

Treatment of the graphite/AsF₅ compound with F₂ gas results in conversion of all of the intercalated arsenic to AsF₆^?.