Search results for " Gold"

Electrochemical detection of dopamine with negligible interference from ascorbic and uric acid by means of reduced graphene oxide and metals-NPs base…

2021

Abstract Dopamine is an important neurotransmitter involved in many human biological processes as well as in different neurodegenerative diseases. Monitoring the concentration of dopamine in biological fluids, i.e., blood and urine is an effective way of accelerating the early diagnosis of these types of diseases. Electrochemical sensors are an ideal choice for real-time screening of dopamine as they can achieve fast, portable inexpensive and accurate measurements. In this work, we present electrochemical dopamine sensors based on reduced graphene oxide coupled with Au or Pt nanoparticles. Sensors were developed by co-electrodeposition onto a flexible substrate, and a systematic investigati…

Selected cytotoxic gold compounds cause significant inhibition of 20S proteasome catalytic activities

2014

Abstract Six structurally diverse cytotoxic gold compounds are reported to cause profound and differential inhibition of the three main catalytic activities of purified 20S proteasome whilst auranofin , an established gold(I) drug in clinical use, is nearly ineffective. In particular, the gold(I) complex [( pbiH ) Au ( PPh 3 )] PF 6 , turns out to be the most potent inhibitor of all three enzyme activities with sub-micromolar IC 50 values. The present results further support the view that proteasome inhibition may play a major – yet not exclusive – role in the cytotoxic actions of gold based anticancer agents.

Silver ions mediated photochemical synthesis of water soluble gold nanoparticles with control over size and morphology

2007

La imagen de la Concha de Oro en los impresos de la Edad Moderna

2020

For centuries, an image commonly associated with Santiago de Compostela (the shell) has accompanied the city of Palermo as well. Since the classical tradition and medieval literature, and then during the Renaissance and Baroque age, this symbol has been connected with other urban symbols (the rivers, the eagle and trhe Genius of Palermo), thus contributing to its historical identity, although in a rather idealistic form. Therefore, the expression «Golden Shell» has been used repeatedly in a large number of books printed during the Modern Age, with multiple meanings. The main purpose was to show those attributes linked with the city's landscape (wealth and beauty) within a specific political…

Soil is the best testifier of the diachronous dawn of the Anthropocene

2021

Humans act at worldwide scale as a growing geomorphic agent since mid‐Holocene (8,200–4,200 y BP) through the pervasive impacts of domestication, deforestation, agriculture, urbanization, and mining. The concept of Anthropocene has been introduced exactly to indicate the timespan in which humans have joined with other natural forces in impacting the outermost shell of the planet and the biosphere. Soils, which are the Earth's skin, are sensitive archives of any major human‐induced local to global change. Especially when buried, soils can permanently preserve the primordial traces of a significant impact of man on the environment, which occurred at different times and rates in different area…

From the great depression to bretton woods: Jacob Viner and international monetary stabilization (1930-1945)

2009

This paper examines Jacob Viner's contribution to the debate and the policy decision-making concerning international monetary policy from the Great Depression to the Bretton Woods agreements. An outstanding member of the so-called 'early Chicago School of Political Economy', Viner was actively engaged in the debate over the causes and cures of the Depression, emphasizing the important role international economic problems played in producing its onset and in reinforcing its duration. During the 1930s Viner was an outspoken supporter of international monetary cooperation, set up to secure exchange rates stability, which he regarded as a paramount factor in restoring business confidence and fo…

Partial Reduction and Selective Transfer of Hydrogen Chloride on Catalytic Gold Nanoparticles

2017

© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim HCl in solution accepts electron density from Au NPs and partially reduces at room temperature, as occurs with other simple diatomic molecules, such as O2 and H2. The activation can be run catalytically in the presence of alkynes to give exclusively E-vinyl chlorides, after the regio- and stereoselective transfer of HCl. Based also on this method, vinyl chloride monomer (VCM) can be produced in a milder and greener way than current industrial processes.

U.I.R.D.A. – Unbuilt Italian Rationalism Digital Archive

2018

For twenty years, the architecture of Italian rationalism through the digital modelling has been investigated. Very often, the production of a model and the consequent representation of tridimensional views, in many case studies, as outcome of the research on architecture have been considered. Actually, the digital model, intended as a critical tool, has to be conceived as a ‘starting point' for graphic analysis of architecture and not as the outcome. Indeed, it is associated to other graphics, sometimes not ‘deducted' from the model, useful for the understanding/translation of architecture. The construction of the model is not the construction of a simple image, operation, which is often c…

Gold nanoparticles/electrochemically expanded graphite composite: A bifunctional platform toward glucose sensing and SERS applications

2019

Abstract An integrated nanogold/expanded graphite based sensor was fabricated by a former electrochemical etching of the pencil lead electrode (PLE) and a later in-situ deposition of gold nanoparticles (AuNPs). The electrochemical pretreatment of PLE (EPLE) created a 3D graphene-like surface, enhanced the electrode surface area and facilitated the electron transfer ability within 5 min without any hazardous chemicals added. The obtained AuNPs/EPLE sensor had an excellent electrochemical response to glucose with a wide linear concentration range, from 0.05 to 38 mM and 38 to 60 mM, and a low detection limit of 5 μM (S/N = 3). Furthermore, the AuNPs/EPLE sensor was successfully employed to de…

The fate of silver ions in the photochemical synthesis of gold nanorods: an Extended X-ray Absorption Fine Structure analysis

2009

Water-soluble gold nanorods (Au NRs) were synthesized using a silver-ion mediated photochemical route under UV irradiation. Extended X-ray Absorption Fine Structure (EXAFS) measurements on the Ag K-edge were performed on samples obtained at different Ag/Au ratios and at increasing irradiation times in order to investigate the fate of silver ions during the growth of Au NRs. EXAFS measurements allowed to probe the chemical state and the local environment of silver in the final product. Experimental data suggest that Ag atoms are placed on top of the Au particles as metallic Ag(0), while no significant contribution to the EXAFS spectra comes from AgBr or other Ag(+) based species. The reporte…