Search results for " Gold"

Functionalized Gold Nanoparticles as an Approach to the Direct Colorimetric Detection of DCNP Nerve Agent Simulant

2013

New functionalized gold nanoparticles have been synthesized and their ability to act as colorimetric molecular probes for the naked-eye detection of nerve agent simulant DCNP has been studied. The detection process is based on the com

Scalable heterogeneous synthesis of metallic nanoparticles and aggregates with polyvinyl alcohol

2009

Here we report on a new route to synthesize colloidal silver and gold nanoparticles, potentially scalable for massive nanoparticle-production. This method is based on the microwave-assisted heterogeneous reduction of the metal salts with polyvinylalcohol. The reaction is carried out in alcohols, which are non-solvents for polyvinylalcohol. Nanoparticles can be very easily separated by filtration. The reaction kinetics are extremely fast. Size-controlled formation of nanoparticle agglomerates is accomplished with a seed-mediated synthesis of nanoparticles upon MW exposure.

Understanding the microscopic origin of gold nanoparticle anisotropic growth from molecular dynamics simulations.

2013

We use molecular dynamics simulations in order to understand the microscopic origin of the asymmetric growth mechanism in gold nanorods. We provide the first atomistic model of different surfaces on gold nanoparticles in a growing electrolyte solution, and we describe the interaction of the metal with the surfactants, namely, cetyltrimethylammonium bromide (CTAB) and the ions. An innovative aspect is the inclusion of the role of the surfactants, which are explicitly modeled. We find that on all the investigated surfaces, namely, (111), (110), and (100), CTAB forms a layer of distorted cylindrical micelles where channels among micelles provide direct ion access to the surface. In particular,…

Effect of Ti(IV) loading on CO oxidation activity of gold on TiO2 doped amorphous silica

2006

Abstract Amorphous SiO 2 , doped with various amount of TiO 2 , was used as support for gold nanoparticles. Gold was deposited through the controlled sol formation technique. The effect of the TiO 2 loading on the structural and surface properties was investigated by transmission electron microscopy, X-ray diffraction, Raman and X-ray photoelectron spectroscopy. The catalytic behavior was tested in the oxidation of CO. A significant enhancement in the activity was observed for the gold supported on mixed oxide with low TiO 2 loading. On the basis of characterization data, the positive effect is assigned to the electronic modification of the Ti(IV) of the newly formed Ti O Si bonds.

Synthesis of rod-shaped gold nanorattles with improved plasmon sensitivity and catalytic activity.

2009

We prepared rod-shaped gold nanorattles solid gold nanorods surrounded by a thin gold shell using a galvanic replacement process starting with silver-coated gold nanorods. These structures are very promising candidates for catalytic applications and optimized plasmon sensors. They combine the advantages of rods (low plasmon resonance frequency, large polarizability, small damping) with the high surface area of hollow structures. The plasmon sensitivity to changes in the dielectric environment is up to 50% higher for gold nanorattles compared to gold nanorods with the same resonance frequency and 6x higher than for plasmons in spherical gold nanoparticles. The catalytic activity measured for…

Exploring the binding of Pt drugs to gold nanoparticles for controlled passive release of cisplatin.

2011

Photocatalytic coalescence of functionalized gold nanoparticles.

2009

A novel strategy for the synthesis of chromophore-functionalized AuNPs with a narrow size distribution is reported. It consists of increasing the size of preprepared NPs by means of a fast (second scale) and clean (light and an organic photocatalyst) method. The results agree with thiolate ligand liberation from the NP surface promoted by photogenerated radicals. This lets gold cores come together and finally coalesce.

Intenzionalità collettiva, ontologia sociale e mindreading

2014

In his Collective Intentions and Actions John Searle argued that having a preintentional sense of others as at least potentially cooperative agents “like me” is a necessary condition of collective intentionality. He also argued, in Rationality in Action, that understanding others qua intentional agents necessarily presupposes rationality because rational constraints are built into the logical structure of intentional phenomena. In this paper we will try to specify further these claims in the light of current debate on mindreading, where other-understanding is spelled out either in terms of automatic, subpersonal simulative mechanisms, or in terms of normative, rational principles. We will a…

Il nobile casato dei Ventimiglia e Donna Felice Ventimiglia Barberini

2017

Nella prima parte del saggio (R.F. Margiotta, Il nobile casato dei Ventimiglia dalla Liguria alla Sicilia) si delinea la storia dei Ventimiglia, provenienti dalla Liguria, insediatisi in Sicilia sin dal Duecento, da Francesco I a Francesco IV Rodrigo, padre di Felice Ventimiglia, e ci si sofferma sulle opere più rappresentative da loro commissionate. Nella seconda parte (M.C. Di Natale, Felice Ventimiglia Barberini dal principato di Castelbuono a Roma) si prende in esame la figura di donna Felice Ventimiglia e se ne ripercorrono le vicende della vita attraverso due significativi documenti: l'inventario dotale della nobildonna, stilato nel 1693, in occasione delle nozze con il principe di pa…

'Reyes, santos y maridos: personajes portugueses en el teatro español del Siglo de Oro'

2015

La realidad portuguesa forma parte del acervo temático del teatro español del Siglo de Oro, que destaca de los lusos su valor en la guerra y su exceso en la pasión. Las interacciones literarias se produjeron en dos sentidos: la tradición lusitana fue tratada en las piezas españolas, y los dramaturgos portugueses escribieron en castellano siguiendo a Lope de Vega en su Arte nuevo de hacer comedias en este tiempo (1609). Aunque la historia y la hagiografía serán las vertientes más explotadas debido a la repercusión de sus protagonistas, en otras ocasiones Portugal servirá de ambientación a conflictos universales. Reyes como don Afonso Henriques, don João II o don Sebastião protagonizan obras …