Synergistic Signaling from Extracellular Matrix–Growth Factor Complexes

Investigations on extracellular matrix (ECM) and growth factor (GF) complexes have revealed an underappreciated phenomenon: they can either negate GF activity or generate synergistic signals for cell function, in particular mitogenesis. ECM and pericellular matrix molecules were first recognized to complex with GFs and regulate GF activity by the seminal observations that basic fibroblast growth factor (bFGF or FGF-2) required binding to a cell-surface heparin sulfate proteoglycan and to its authentic cell-surface receptor for biological activity (Klagsbrun and Baird, 1991; Yayon et al., 1991). Subsequently, numerous ECM–GF interactions that modulate GF activity were discovered; we have reviewed many of these findings (Macri et al., 2007)

Improved repeatability measures for evaluating performance of feature detectors

The most frequently employed measure for performance characterisation of local feature detectors is repeatability, but it has been observed that this does not necessarily mirror actual performance. Presented are improved repeatability formulations which correlate much better with the true performance of feature detectors. Comparative results for several state-of-the-art feature detectors are presented using these measures; it is found that Hessian-based detectors are generally superior at identifying features when images are subject to various geometric and photometric transformations

Transforming Growth Factor-β Stimulates the Expression of Fibronectin by Human Keratinocytes

abstractTransforming growth factor beta (TGF-β)is a 25-kD protein which has regulatory activity over a variety of cell types. It is distinct form epidermal growth factor (EGF) and EGF analogs, and exerts its action via a distinct receptor. Its effect on proliferation or differentiation can be positive or negative depending on the cell type and the presence of other growth factors. it also modulates the expression of cellular products. TGF-β causes fibroblasts to increase their production of the extracellular matrix components, fibronectin and collagen. human keratinocytes (HK) are known to have TGF-βreceptors. We wished to study the effect of TGF-β on the production of extracellular matrix proteins by human keratinocytes in culture.Human keratinocytes were grown in serum-free defined medium (MCDB-153) to about 70% confluence. Following a 16-h incubation in medium lacking EGF and TGF-β, cells were incubated for 12h in medium containing varying concentrations of EGF and TGF-β. Cells were then labeled with 35S-methionine for 10 h in the same conditions. Labeled proteins from the medium were analyzed by SDS-PAGE and autoradiography.TGF-β at 10 ng/ml induced a sixfold increase in the secretion of fibronectin, as well as an unidentified 50-kD protein. Thrombospondin production was also increased, but not over a generalized twofold increase in the production of all other proteins. EGF, at 10 ng/ml, caused a smaller additive effect, TGF-β may be an important stimulator of extracellular matrix production by human keratinocytes

Annealing Effect for Supersolid Fraction in 4^4He

We report on experimental confirmation of the non-classical rotational inertia (NCRI) in solid helium samples originally reported by Kim and Chan. The onset of NCRI was observed at temperatures below ~400 mK. The ac velocity for initiation of the NCRI suppression is estimated to be ~10 $\mu$m/sec. After an additional annealing of the sample at $T= 1.8$ K for 12 hours, ~ 10% relative increase of NCRI fraction was observed. Then after repeated annealing with the same conditions, the NCRI fraction was saturated. It differs from Reppy's observation on a low pressure solid sample.Comment: to be published in J. of Low Temp. Phys. (QFS2006 proceedings

Break-junction tunneling measurements of the high-\u3ci\u3eT\u3c/i\u3e\u3csub\u3e\u3ci\u3ec\u3c/i\u3e\u3c/sub\u3e superconductor Y\u3csub\u3e1\u3c/sub\u3eBa\u3csub\u3e2\u3c/sub\u3eCu\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e9- δ \u3c/sub\u3e

Current-voltage tunneling characteristics in a high-critical-temperature superconducting material containing predominately Y1Ba2Cu3O9- δ have been measured using the break-junction technique. Sharp gap structure was observed, with the largest superconductive energy gap measured to be Δ=19.5±1 meV, assuming a superconductor-insulator-superconductor junction. This energy gap corresponds to 2Δ/kBTc=4.8 at T=4 K, for a critical temperature of 93 K (midpoint of the resistive transition)

Near-Earth asteroid sample return missions

The rate of discovery of new NEAs and the success of D-S 1 and NEAR-Shoemaker, suggest that sample return from NEAs is now technically feasible. Here we present a summary of a recent workshop on the topic

Andreev Reflections in Micrometer-Scale Normal-Insulator-Superconductor Tunnel Junctions

Understanding the subgap behavior of Normal-Insulator-Superconductor (NIS) tunnel junctions is important in order to be able to accurately model the thermal properties of the junctions. Hekking and Nazarov developed a theory in which NIS subgap current in thin-film structures can be modeled by multiple Andreev reflections. In their theory, the current due to Andreev reflections depends on the junction area and the junction resistance area product. We have measured the current due to Andreev reflections in NIS tunnel junctions for various junction sizes and junction resistance area products and found that the multiple reflection theory is in agreement with our data