Search results for " Gold"
showing 10 items of 278 documents
Gold nanoparticles stabilized by modified halloysite nanotubes for catalytic applications
2019
A highly sustainable prototype of a flow system based on gold nanoparticles (4.2 nm) supported on thiol-functionalized halloysite nanotubes (HNTs) was developed for catalytic applications. The catalytic performances were evaluated using the reduction of 4-nitrophenol to 4-aminophenol as a model system. Under the best experimental conditions (0.0001 mol%, 1.97 × 10−8 mg of Au nanoparticles), an impressive apparent turnover frequency value up to 2 204 530 h−1 was achieved and the halloysite-based catalyst showed full recyclability even after ten cycles. The high catalytic activity confirms the importance of the use of HNTs as support for Au nanoparticles that can exert a synergistic effect bo…
Au deposited on CeO2 prepared by a nanocasting route: A high activity catalyst for CO oxidation
2014
Abstract A set of catalysts comprised of gold on different CeO 2 supports has been prepared by a nanocasting route and characterized by several physicochemical techniques. These catalysts have been tested for CO oxidation and show outstanding catalytic activity. Higher calcination temperatures of the hard template, producing a poorly ordered silica template, have led to a higher amount of oxygen vacancies on the surface of CeO 2 . The presence of surface oxygen defects in the support combined with the deposition of Au nanoparticles ( ca. 3 nm) homogeneously dispersed on the CeO 2 support may explain the excellent behaviour for low temperature CO oxidation. Surprisingly, it has been observed…
Gold-nanoparticles ingestion disrupts reproduction and development in the German cockroach.
2015
The present work shows the effects of gold nanoparticles (AuNPs) orally administered on reproduction and development of the insect Blattella germanica. Newly emerged females were provided with food containing AuNPs (87.44μg/g) of a size between 15 and 30nm (mean 21.8nm), and were allowed to mate with males. Food ingestion, mortality, reproductive parameters (time to ootheca formation and eclosion, ootheca viability and fertility) as well as postembryonic developmental parameters of the first ootheca (nymphal survival and life span) were recorded throughout the experiment. Gold from AuNPs was accumulated by adults of B. germanica with a bioaccumulation factor of 0.1. Ingestion of AuNPs did n…
CO Oxidation on Cationic Gold Clusters: A Theoretical Study
2008
Aiming at understanding the elementary steps governing the oxidation of CO catalyzed by dispersed or supported gold nanoclusters, the reactivity of molecular species, such as O2 and CO, on neutral and positively charged Au13 clusters have been studied using a DFT approach. Two CO oxidation mechanisms have been simulated, involving respectively the adsorption of CO and O2 on adjacent catalytic sites (two-sites mechanism) and the competitive interaction of the reactants on the same site (single-site mechanism). It is demonstrated that in the former scheme a definite interaction of CO and O2 with both the charged and neutral cluster is effective, but that a chemical reaction between the adsorb…
Colloidal Self-assembled Nanosphere Arrays for Plasmon-enhanced Light Trapping in Thin Film Silicon Solar Cells
2014
To realize high-efficiency thin-film silicon solar cells it is crucial to develop light-trapping methods that can increase absorption of the near- bandgap light in the silicon material. That can be achieved using the far-field scattering properties of metal nanoparticles (MNP) sustaining surface plasmons. The MNPs should be inserted in the back of the cell, embedded in the transparent conductive oxide (TCO) layer which separates the rear mirror from the silicon layers. In this way, a plasmonic back reflector (PBR) is constructed that can redirect light at angles away from the incidence direction and thereby increase its path length in the cell material. In this work, a novel technique is pr…
Women in contemporary English drama translation: enhancement and downplay mechanisms to portray Golden Age damas
2011
In the last two decades British and American drama translators have shown a growing interest in the Spanish classics, resulting in English versions exclusively intended for the stage. Within this particular context, this paper is intended to provide a general view on how a motif present in the source texts, i.e. the role of women, is transferred into the target plays. A close analysis of the translated works reveals how women’s acts can be enhanced or downplayed in order to accommodate them to the recipient culture. Hence, political correctness, reaction to male domination, moral squeamishness and honour emerge as important elements to be taken into account. Conclusions will ultimately prov…
Imagen e iconografía en las exequias del príncipe Baltasar Carlos en Zaragoza en 1646.
2014
ABSTRACT: This article studies the ceremonial funeral rites for Prince Baltasar Carlos of Austria, son of Philip IV and the hope for the healing of a monarchy in crisis, in the exequies celebrated in the city of Zaragoza, where the young heir to the throne died shortly before his seventeenth birthday, in 1646. The monumental catafalque erected in the plaza of the market place (a fantastic ephemeral tumulus characterized by a splendid Baroque architecture full of symbols), demonstrates the magnificence with which the death of such a beloved prince was presented to the public, in the second third of the seventeenth century. KEYWORDS: Prince Baltasar Carlos of Austria, Spanish Golden Age, roya…
Extracts deriving from olive mill waste water and their effects on the liver of the goldfish Carassius auratus fed with hypercholesterolemic diet
2014
The present research aims to evaluate the beneficial effects of polyphenols derived from waste water from a olive mill, obtained by non-plastic molecular imprinting device, in a hypercholesterolemic diet on Carassius auratus, commonly known as goldfish that was selected as experimental model. The study was conducted with morphological and histochemical analyses and also the data were supported by immunohistochemical analysis. Results show the beneficial activity of polyphenols with a reduction of the damage in the steatotic group, confirming that they may be suggested in the treatment of diseases by lipid accumulation, and used as any addition in feed for farmed fish, in order to improve th…
Aukso vilna ir auksavilnis avinas: antikinių literatūros šaltinių liudijimai ir interpretacija
2018
The Golden Fleece figures in Greek mythology as the objective of the voyage of the Argonauts. The incompatability of the object of the search with the effort invested in its acquisition has furthered discussion of the real meaning of the Golden Fleece, which has generally been accepted to be a metaphor since antiquity. Modernity, especially at the turn of the 19th and 20th centuries, has been productive and inventive in the decipherment attempts of the metaphor’s hidden meaning. A number of interpretation theories has been developed, which, though interesting and wellargumented, are sometimes highly divergent from the interpretation of the Golden Fleece in the ancient sources. A proper unde…
Novel two-step synthesis of gold nanoparticles capped with bile acid conjugates
2008
Bile acids and their conjugates are physiologically important molecules. Syntheses and structure elucidation combined with investigation of properties and applications of bile acids and their derivatives are of academic interest. The concept of using bile acids and their conjugates in nanoscience is a novel idea, which opens up fascinating prospects. In this article, an easy and simple route for obtaining N-lithocholyl-L-(cysteine ethyl ester) (3), capable of effectively capping and stabilizing metal nanoparticles, is described. The whole synthetic route needs only two steps giving a moderate to good yield. The gold NPs are characterized by elemental analysis, UV spectroscopy, and TEM. Addi…