Search results for "pero"
showing 10 items of 3365 documents
Changes of 1-Aminocyclopropane-1-Carboxylic Acid Oxidase Activity in Stressed Pinus Sylvestris Needles
2001
Stimulation of ethylene biosynthesis in pine needles by hydrogen peroxide and sodium bisulfite coincided with the activation of ACC oxidase at the level of protein synthesis. Decrease in ethylene production at high concentrations of sodium bisulfite (above 7 mM) was apparently due to inhibition of ACC oxidase activity. Treatment of pine needles with aminotriazole caused an inhibition of both ethylene production and ACC oxidase activity. Both methylviologen and methyl jasmonate stimulated ACC oxidase activity in a concentration-dependent manner with no parallel changes in ethylene production. The presented results suggest that ACC oxidase plays an important role in regulation of ethylene for…
Grafting of Hindered Phenol Groups onto Ethylene/α-Olefin Copolymer by Nitroxide Radical Coupling
2017
The covalent immobilization of hindered phenol groups, with potential antioxidant activity, onto an ethylene/α-olefin (EOC) copolymer was carried out by the nitroxide radical coupling (NRC) reaction performed in the melt with a peroxide and the 3,5-di-tert-butyl-4-hydroxybenzoyl-2,2,6,6-tetramethylpiperidine-1-oxyl radical (BHB-T). Functionalized EOC (EOC-g-(BHB-T)) was exposed to photo- and thermo-oxidation. By comparison with some model compounds bearing the (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) moiety or the hindered phenol unit, it was observed that the grafted BHB-T could effectively help the stabilization of the polymer matrix both under photo- and thermo-oxidation. In addit…
Modulation of Solanum tuberosum L. morphogenesis and antioxidative status in a stem explant culture by limitation of gas exchange: Putative effects o…
2000
Summary The main objective of the present study was to test the hypothesis that increased concentrations of ethylene under conditions of limited gas exchange during in vitro cultivation of potato ( Solanum tuberosum L.) stem explants may lead to increased capaciry of antioxidative defense. By varying the tightness of closure and application of inhibitors of ethylene biosynthesis it was possible to accumulate various concentrations of ethylene in the internal atmosphere of culture flasks, which depended on excision-stress induced ethylene biosynthesis. In tightly closed cultures inhibition of linear growth, promotion of radial expansion and development of an apical hook occurred. Treatment w…
Introduzione a "La Sicilia del gesso. Stratificazione, tecniche costruttive e cultura" (Atti del convegno omonimo, Caltanissetta, 12 gennaio 2019)
2020
L'introduzione al volume illustra il percorso e le finalità con cui si è giunti all'organizzazione del convegno "La Sicilia del gesso. Stratificazione, tecniche costruttive e cultura", inserito all'interno delle attività di divulgazione scientifica del Consorzio universitario di Caltanissetta presieduto dal dott. Giovanni Arnone, che ha curato la premessa del volume stesso.
Towards the fluorogenic detection of peroxide explosives through host-guest chemistry
2018
[EN] Two dansyl-modified beta-cyclodextrin derivatives (1 and 2) have been synthesized as host-guest sensory systems for the direct fluorescent detection of the peroxide explosives diacetone diperoxide (DADP) and triacetone triperoxide (TATP) in aqueous media. The sensing is based on the displacement of the dansyl moiety from the cavity of the cyclodextrin by the peroxide guest resulting in a decrease of the intensity of the fluorescence of the dye. Both systems showed similar fluorescent responses and were more sensitive towards TATP than DADP.
Quantum mechanics-molecular dynamics approach to the interpretation of x-ray absorption spectra.
2009
The quantum mechanics-molecular dynamics approach to the simulation of configuration-averaged EXAFS spectra is proposed, and its application is discussed for the example of the Ti K-edge EXAFS spectrum in cubic perovskite SrTiO(3). Proper use of ab initio quantum mechanics allows a number of empirical parameters, used in the molecular dynamics simulation, to be reduced, whereas the molecular dynamics allows us to account for temperature effects. All together, the approach provides a way of accounting for static and dynamic disorder in EXAFS signals from the coordination shells above the first one, where many-atom (multiple-scattering) effects are often important.
Toward tailorable surfaces: a combined theoretical and experimental study of lanthanum niobate layered perovskites.
2014
A comprehensive theoretical investigation of the MLaNb2O7 (M = H, Li, Na, K, Rb, and Cs) series of ion-exchangeable layered perovskite is presented. These perovskites are in particular interesting in view of their potential applications as inorganic supports for the design of new hybrid inorganic-organic proton conductors. In particular, their structural and electronic properties have been investigated by periodic calculations in the framework of Density Functional Theory, using different exchange-correlation functionals. A general very good agreement with the available experimental (XRD, NPD, and EXAFS) data has been found. The structure of the protonated HLaNb2O7 form has also been furthe…
Extended X-Ray Absorption Fine Structure Spectroscopy of Perovskite-Type Compounds
2000
Application of the extended x-ray absorption fine structure (EXAFS) spectroscopy to a study of the local atomic structure in perovskitetype materials is discussed on the example of several compounds (m-WO3, NaxWO3, ReO3 and FeF3). The sensitivity of the EXAFS to the out-of-center and rotational distortions is discussed in details.
Firing characteristics of vestibular nuclei neurons in the alert monkey after bilateral vestibular neurectomy
1992
After destruction of the peripheral vestibular system which is not activated by moving large-field visual stimulation, not only labyrinthine-ocular reflexes but also optokinetic-ocular responses related to the "velocity storage" mechanism are abolished. In the normal monkey optokinetic-ocular responses are reflected in sustained activity changes of central vestibular neurons within the vestibular nuclei. To account for the loss of optokinetic responses after labyrinthectomy, inactivation of central vestibular neurons consequent on the loss of primary vestibular activity is assumed to be of major importance. To test this hypothesis we recorded the neural activity within the vestibular nuclea…
Extraction of Singlet States from Noninteracting High-Dimensional Spins
2008
We present a scheme for the extraction of singlet states of two remote particles of arbitrary quantum spin number. The goal is achieved through post-selection of the state of interaction mediators sent in succession. A small number of iterations is sufficient to make the scheme effective. We propose two suitable experimental setups where the protocol can be implemented.