Our results demonstrate that NIH-3T3 cells overexpressing a mutant form of the Igf1r gene, in which arginine at 481 is substituted by glutamine, lead to reduced levels of the fold increase of IGF-IR beta-subunit phosphorylation as well as ERK1/2 and Akt phosphorylation and was accompanied by decreased cell proliferation. These results are postulated to be the cause of intrauterine and postnatal growth retardation in the described patients.

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2-NO 2 -5,10,15,20-tetraphenylporphyrin (H 2 TPP-NO 2 ) is shown to exist in solution as an equilibrium mixture of two NH tautomers with different spectral and photophysical properties. At 77 K in a rigid glass solution the fluorescence spectra of the tautomers contain two well-resolved narrow bands that are slightly (∼300 cm -1 ) Stokes-shifted with respect to the corresponding Q X00 absorption bands, with the spectrum of the more stable tautomer being ∼500 cm -1 red-shifted as compared to the spectrum of the less stable tautomer. At room temperature, the tautomers show almost identical broad and structureless fluorescence spectra, markedly red-shifted relative to the longest wavelength absorption band. The Stokes shift increases with an increase of solvent polarity, being as large as ∼2000 cm -1 in N,N-dimethylformamide. Fluorescence lifetimes of the tautomers are found to be markedly (about a factor of 2) different, with both decreasing with an increase of solvent polarity. The reasons for these peculiar fluorescence properties can be understood on the basis of semiempirical quantum chemical calculations. Charge-transfer (CT) states are found to be located between the porphyrinic Q and B states for both tautomers, and a different energy of the CT states gives rise to different fluorescence lifetimes of the tautomers. The calculations also predict a lowering of the Q X state energy and an increase of its dipole moment µ with a decrease of the angle θ between the plane of the NO 2 group and the porphyrin plane (relative to the ground-state equilibrium geometry with θ ) 80°). We suggest that, in solution, such an increase in the µ value should result in an increase of the stabilization interaction between the polar porphyrin and solvent molecules and, consequently, in flattening of the Q X state energy curve as a function of θ and a shift of the minimum of this curve to θ values less than 80°. Both quantum chemical calculations and picosecond transient absorption measurements of the S 1 f S n absorption show that the fluorescent Q X state of H 2 TPP-NO 2 has mainly 1 (π,π*) character with a relatively small charge-transfer admixture.

The present work gives an overview of the developments in surface-enhanced Raman scattering (SERS) with metal-coated porous silicon used as an active substrate. We focused this review on the research referenced to SERS-active materials based on porous silicon, beginning from the patent application in 2002 and enclosing the studies of this year. Porous silicon and metal deposition technologies are discussed. Since the earliest studies, a number of fundamentally different plasmonic nanostructures including metallic dendrites, quasi-ordered arrays of metallic nanoparticles (NPs), and metallic nanovoids have been grown on porous silicon, defined by the morphology of this host material. SERS-active substrates based on porous silicon have been found to combine a high and well-reproducible signal level, storage stability, cost-effective technology and handy use. They make it possible to identify and study many compounds including biomolecules with a detection limit varying from milli- to femtomolar concentrations. The progress reviewed here demonstrates the great prospects for the extensive use of the metal-coated porous silicon for bioanalysis by SERS-spectroscopy.