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showing 10 items of 7386 documents
Watching adsorption and electron beam induced decomposition on the model system Mo(CO)(6)/Cu(111) by X-ray absorption and photoemission spectroscopies
2013
Abstract An in-depth study of the first steps of electron beam assisted growth of Mo from molybdenum hexacarbonyl on Cu(1 1 1) has been carried out exploiting the complementarity of X-ray photoemission and X-ray absorption spectroscopies. Frank van der Merwe (2D) growth mode has been observed for the completion of the two first monolayers of adsorbed molecules through a simple physisorption process. Irradiation of the Mo(CO)6 deposit by 1 keV electron beam induces a modification of molybdenum coordination, the average number of C-neighbors decreasing from 6 to 3. Decomposed molecules remain on the surface after annealing at 520 K and organize themselves, the molybdenum atoms moving in Cu(1 …
Computed positron lifetimes in vacancies and vacancy-iron clusters in gold
1983
Abstract Annihilation characteristics are calculated for positrons trapped in clean and impurity decorated vacancy clusters in Au. The positron lifetime depends strongly on the structure of the clusters. In a strongly relaxed vacancy cluster, the lifetime can become smaller than the lifetime in a single vacancy. The substitution of some neighbour atoms of a vacancy cluster by Fe atoms has only a minor effect on the positron lifetimes.
1,2‐Benzothiazine Derivatives from Sulfonimidamides by Metal‐Catalyzed Annulation Reactions in Solution and under Solvent‐Free Mechanochemical Condit…
2021
Advanced synthesis & catalysis (2021). doi:10.1002/adsc.202001505 special issue: "Hot Topic: C-H Activation"
Investigation on the influence of spray-drying technology on the quality of Sicilian Nero d’Avola wines
2018
The purpose of the present work was to find a correlation between microencapsulation technology applied to wines and the resulting quality of the wine itself in terms of volatile composition and phenolic profile. To this aim, samples of Nero d'Avola wines produced in Sicily (Italy) were investigated in order to: i) elucidate the aromatic composition by means of HSâSPME coupled with GCâMS; ii) assess the polyphenolic content by UHPLC mass spectrometry; iii) compare the results obtained from both the screenings with those relative to the same wines that had previously been subjected to spray-drying. The results showed a marked reductionThe results here obtained evidenced a marked reductio…
Anti-Pseudomonas aeruginosa activity of hemlock (Conium maculatum, Apiaceae) essential oil
2018
Conium maculatum is a nitrophilous weed belonging to the Apiaceae family and occurring in hedgerows, pastures, waste ground, along rivers and roadsides. Little is known on the chemistry and bioactivity of other secondary metabolites occurring in the plant. In the present work, we have analysed the chemical composition and antimicrobial activity of the essential oils hydrodistilled from leaves and inflorescenes of C. maculatum growing in Sicily, Italy. The composition of essential oils was achieved by gas chromatography-mass spectrometry (GC-MS) analysis, whereas the inhibitory effects on the growth of two Gram negative strains, namely Escherichia coli and Pseudomonas aeruginosa were assesse…
Zanhasaponins A and B, Antiphospholipase A2 Saponins from an Antiinflammatory Extract of Zanha africana Root Bark
1997
A MeOH extract from Z. africana was examined for topical antiinflammatory activity and proved to be active against arachidonic acid (AA) acute edema, 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced chronic inflammation, and oxazolone delayed-type hypersensitivity in mice. The extract also showed significant inhibitory activity of Naja naja phospholipase A2 when a polarographic method was used. Two oleanane-type triterpene saponins, zanhasaponins A (1) and B (2), and the cyclitol pinitol (4), isolated from the extract, were active as inhibitors of PLA2. A further saponin, zanhasaponin C (3) was inactive in this assay.
Preíndices que determinan la anticipación del portero de hockey hierba ante un golpeo de revés
2015
La tesis se encuadra en el estudio de los elementos perceptivos y atencionales que modulan la captación de información, aspecto clave para la toma de decisión y posterior acción motriz que conforman el modelo de procesamiento de la información (Marteniuk, 1976). Para la correcta ejecución de muchas de las acciones que se realizan en la actividad deportiva, la capacidad de extraer del entorno la información más relevante y procesarla adecuadamente es esencial. Esta capacidad se torna más relevante aún en los deportes de predominio de situaciones abiertas, como las que caracterizan a los deportes de equipo, donde la dinámica del entorno en el que se desarrollan las acciones genera gran cantid…
Possible Fungistatic Implications of Betulin Presence in Betulaceae Plants and their Hymenochaetaceae Parasitic Fungi
2010
Betulin and its derivatives (especially betulinic acid) are known to possess very interesting prospects for their application in medicine, cosmetics and as bioactive agents in pharmaceutical industry. Usually betulin is obtained by extraction from the outer layer of a birch bark. In this work we describe a simple method of betulin isolation from bark of various species of Betulaceae trees and parasitic Hymenochaetaceae fungi associated with these trees. The composition of the extracts was studied by GC-MS, whereas the structures of the isolated compounds were confirmed by FTIR and 1H NMR. Additionally, the significant fungistatic activity of betulin towards some fi lamentous fungi was deter…
Phenolic Compounds Characterization and Antioxidant Properties of Monocultivar Olive Oils from Northeast Algeria
2020
In Algeria, the olive tree is one of the main fruit species and plays a very important socioeconomic role. The objective of this study was firstly, to identify and quantify the phenolics of some Algerian olive oils, and secondly, to assess the antioxidant activity of the samples. The olive oils used in this study were derived from Algerian cultivars, including Tefahi, Gelb Elfarroudj, Chemlal, and imported cultivar Manzanilla and Zebboudj. For this purpose, gas chromatography&mdash
Role of paramagnetic polyconjugated clusters in lignin antioxidant activity(in vitro)
2012
Using physico-chemical methods (EPR, SEC, Py-GC/MS and UV/VIS spectroscopy) and wet chemical analysis, the characteristics of 6 hardwood lignins in terms of functionality, molecular weight and composition of lignin substructures were determined and considered together with the results of DPPH•, ABTS•+ and O2•− antioxidant assays with the aim to understand the relationships governing antioxidant properties of lignin. The strong positive linear correlation between lignin antioxidant capacity in the three assays used and the extent of conjugation of paramagnetic polyconjugated clusters in lignin macromolecules was found. The biological activity of the most active alkaline lignins was assessed …