Search results for " radical"
showing 10 items of 757 documents
A synergic nanoantioxidant based on covalently modified halloysite–trolox nanotubes with intra-lumen loaded quercetin
2016
We describe the preparation and properties of the first example of a synergic nanoantioxidant, obtained by different functionalizations of the external surface and the inner lumen of halloysite nanotubes (HNTs). Trolox, a mimic of natural α-tocopherol, was selectively grafted on the HNT external surface; while quercetin, a natural polyphenolic antioxidant, was loaded into the inner lumen to afford a bi-functional nanoantioxidant, HNT–Trolox/Que, which was investigated for its reactivity with transient peroxyl radicals and a persistent 1,1-diphenyl-2-picrylhydrazyl (DPPH˙) radical in comparison with the corresponding mono-functional analogues HNT–Trolox and HNT/Que. Both HNT–Trolox and HNT/Q…
Aqueous-phase reactive species formed by fine particulate matter from remote forests and polluted urban air
2021
In the aqueous phase, fine particulate matter can form reactive species (RS) that influence the aging, properties, and health effects of atmospheric aerosols. In this study, we explore the RS yields of aerosol samples from a remote forest (Hyytiälä, Finland) and polluted urban locations (Mainz, Germany; Beijing, China), and we relate the RS yields to different chemical constituents and reaction mechanisms. Ultra-high-resolution mass spectrometry was used to characterize organic aerosol composition, electron paramagnetic resonance (EPR) spectroscopy with a spin-trapping technique was applied to determine the concentrations of ⚫OH, O2⚫-, and carbon- or oxygen-centered organic radicals, and a …
Superoxide-driven autocatalytic dark production of hydroxyl radicals in the presence of complexes of natural dissolved organic matter and iron
2020
We introduced superoxide as potassium superoxide (KO2) to artificial lake water containing dissolved organic matter (DOM) without or with introduced ferric iron complexes (DOM-Fe), and monitored the production rate of hydroxyl radicals as well as changes in the absorption and fluorescence properties of DOM. The introduction of KO2 decreased the absorption by DOM but increased the spectral slope coefficient of DOM more with complexed ferric Fe than without it. The introduction of KO2 increased the fluorescence of humic-like components in DOM without introduced ferric Fe but resulted in the loss of fluorescence in DOM with introduced ferric Fe. A single introduction of 13 μmol L−1 KO2 produce…
Facile Synthesis of Fluorescent Polymer Nanoparticles by Covalent Modification-Nanoprecipitation of Amine-Reactive Ester Polymers
2015
Emission wavelength control in fluorescent nanoparticles (NPs) is crucial for their applications. In the case of inorganic quantum dots or dye-impregnated silica NPs, such a control is readily achieved by changing the size of the particles or choosing appropriate fluorescent dyes, respectively. A similar modular approach for controlling the emission wavelength of fluo-rescent polymer NPs, however, is difficult. This article reports on fluorescent polymer NPs, the synthesis of which provides a platform for a modular approach towards the preparation of fluorescent NPs of desired emission wavelength. Atom-transfer radical polymerization (ATRP) is employed to synthesize reactive ester polymers,…
Experimental and computational studies of unconventional main group compounds : stable radicals and reactive intermediates
2017
Ever since their discovery, radicals have intrigued the minds of experimental and theoretical chemists alike. While the vast majority of radicals are transient species, a large number of stable and persistent radicals are also known. This has enabled the use of radicals in different applications. For example, radicals are highly useful in chemical synthesis due to their selectivity and functional group tolerance. Detailed knowledge of the electronic structure of synthetic intermediates, both radical and non-radical, enables chemists to improve existing synthesis routes and to design completely new ones. This thesis is divided into two parts. The first part begins with an introduction to the…
Laparoscopic versus open retropubic intrafascial nerve-sparing radical prostatectomy: surgical and functional outcomes in 300 patients
2010
La radicalidad del mal banal
2002
El concepto de ‘banalidad del mal’ fue introducido por Hannah Arendt a fin de caracterizar una forma inédita de perversidad que ella vio encarnada en Adolf Eichmann y otros criminales nazis. Arendt consideraba que esa forma de perversidad estaba muy alejada de la noción de ‘mal radical’ que Kant había acuñado y la propia Arendt había empleado en trabajos anteriores. El objetivo principal del artículo es mostrar que hay más afinidades entre el mal radical kantiano y la banalidad del mal de lo que la propia Arendt reconoce. ‘Banality of evil’ was a concept introduced by Hannah Arendt in order to characterize a new form of wickedness embodied in people as Adolf Eichmann and others nazis crimin…
«(Des)obediències de la reducció vocàlica en el català de Mallorca»
2013
En el català de Mallorca, el procés de reducció vocàlica de les vocals mitjanes de la sèrie anterior a e neutra en posició àtona no opera (o subaplica) en determinades circumstàncies: (a) en formes derivades productives amb una vocal àtona situada a la síl·laba esquerra o inicial del radical i alternant amb e tancada o e oberta en el radical de la forma primitiva; (b) en formes verbals amb una vocal àtona situada a la síl·laba esquerra o inicial del radical i alternant amb e tancada en una altra forma verbal del mateix paradigma flexiu; (c) en manlleus i paraules apreses amb una vocal àtona e situada, també, a la síl·laba esquerra o inicial del radical i generalment precedida d’una consonan…
VOX Spain: The Organisational Challenges of a New Radical Right Party
2021
This article examines the organisation of VOX, a new radical right party in Spain. It shows that the party has taken early and uneven steps to build a mass organisation and initially opted for open membership recruitment with participatory organisational elements. Also, the party’s rapid growth and quick entrance into political institutions at different state levels led the party leadership to establish more centralised control and limit members’ prerogatives, though recruitment continued. Centralisation in part responds to organisational needs given the party’s quickly acquired political relevance, but also to the desire of the central party leadership to forestall the articulation of terr…