A way to decylamine-stabilized gold nanoparticles of tailored sizes tuning their growth in solution

Acetone solvated Au nanoparticles (Au NPs) were prepared by Metal Vapour Synthesis (MVS) co-condensing Au and acetone vapours. Nanoparticles growth was quenched at different times by using decylamine (DA) as stabilizer and DA-stabilized Au NPs were characterized by UV-Vis, NMR DOSY and HRTEM techniques. The dependence of metal clustering processes on gold concentration was investigated.     

Effects of interleukins on Crouzon fibroblast phenotype in vitro. Release of cytokines and IL-6 mRNA expression

In Crouzon's syndrome, the cranial morphogenic processes are altered due to the early fusion of the facial and basal cranial bones. Evidence that Crouzon fibroblasts have an altered phenotype which is modulated by interleukin 1 (IL-1) and interleukin 6 (IL-6) is provided. [3H]Thymidine incorporation and cell count studies showed that Crouzon fibroblasts have an accelerated proliferation rate. [3H]Glucosamine incorporation studies, followed by chromatography analysis of culture medium samples, revealed that the various classes of glycosaminoglycans (GAG) secreted into the medium were differently distributed in Crouzon and normal fibroblasts. Crouzon fibroblasts secreted less total GAG, particularly hyaluronic acid (HA) and heparan sulfate (HS), but a relatively greater quantity of chondroitin sulfate. Type I and III collagen were raised in Crouzon fibroblast medium whereas the concentration of fibronectin was lower than in normal cells. Interleukin treatment induced changes in cell growth and neosynthesis of extracellular matrix macromolecules. Both IL-1 and IL-6 stimulated proliferation of Crouzon fibroblasts, whereas only IL-6 increased [3H]thymidine incorporation in normal cells. IL-1 provided a drop in HA and a rise in GAG sulfates in normal fibroblasts, but caused an opposite effect in Crouzon fibroblasts. Type I collagen and fibronectin secretions are differently modulated by the cytokines in the two populations. Moreover, level of IL-1 able to stimulate [3H] thymidine incorporation into mouse thymocytes, and level of IL-1 receptor antagonist (IL-1ra), as determined by ELISA, were higher in pathological than in normal fibroblasts. Also evidence that levels of IL-1 alpha and IL-6 proteins measured by ELISA and also IL-6 mRNA expression are enhanced in Crouzon fibroblasts is provided. These novel data suggested that, in Crouzon's syndrome, the modifications in the relative concentrations of the extracellular matrix (ECM) components associated with the abnormal cytokine networks may alter the balance of the microenvironment where the morphogenic events take place.     

Addressing the magnetic properties of sub-monolayers of single-molecule magnets by X-ray magnetic circular dichroism

We report on a comparative study of electronic and magnetic properties of Mn6 single-molecule magnets (SMMs) grafted on gold surface. Two derivatives with spin-ground states S=4 and S=12 have been functionalized with 3-tp-CO2- (3-thiophene carboxylate, tpc) ligands and characterized as thick films (TFs) as well as sub-monolayers (sMLs) by synchrotron based techniques. X-ray absorption spectroscopy at the Mn L2,3 edges shows the modification of the spectral lineshape in the sMLs with respect to the TFs suggesting that the local symmetry at the Mn sites changes once the molecules are deposited on gold surface. In spite of this, the expected MnIII oxidation state is preserved. X-ray magnetic circular dichroism (XMCD) spectra show that the total magnetic moment is only given by spin part because of the quenched orbital moment. Moreover, variable temperature and variable field XMCD spectra reveal an effective decrease of the Mn spin moment for both derivatives.     

Some experiments in the evaluation of a character recognition scanner

For character recognition machines in which the design of the logic is time consuming and expensive, a method for evaluating the character recognition scanner prior to designing the recognition logic is desirable. A method for evaluating a character recognition scanner by evaluating the patterns it produces is described. The method, for a given set of parameters, assigns to each pattern a figure of merit that measures the difficulty of recognizing the pattern. A number of experiments show that the evaluation method produced results comparable to results produced by a recognition logic designed by engineers. On a sample of 81,200 patterns, the evaluation method showed in this experiment that 0.20% of the patterns would be difficult to recognize, while for the same patterns, logic designed by engineers failed to recognize or misrecognized 0.24% of the patterns.