Search results for "chimica"

Ni-Based Alloy Nanostructured Electrodes for Alkaline Electrolyzers

In water alkaline electrolyzer field, the development of Nickel-based nanostructured electrode is one of the possible ways to improve the water electrolysis efficiency

Cytotoxic Activity and Composition of Petroleum Ether Extract from Magydaris tomentosa (Desf.) W. D. J. Koch (Apiaceae)

2015

The petroleum ether extract of Magydaris tomentosa flowers (Desf.) W. D. J. Koch has been analyzed by GC-MS. It is mainly constituted by furanocoumarins such as xanthotoxin, xanthotoxol, isopimpinellin, and bergaptene. Other coumarins such as 7-methoxy-8-(2-formyl-2-methylpropyl) coumarin and osthole also occurred. The antiproliferative activity of Magydaris tomentosa flower extract has been evaluated in vitro on murine monocye/macrophages (J774A.1), human melanoma (A375) and human breast cancer (MCF-7) tumor cell lines, showing a major activity against the latter.

Materiali ibridi a base di nanotubi di allosite per la rimozione d’inquinanti

2017

L’allosite (HNT) è un interessante materiale argilloso allumino-silicato naturale, non tossico e biocompatibile, con la caratteristica forma tubolare cava dotata di parziale carica positiva interna e negativa esterna.Combinando le peculiarità di un composto organico con le proprietà di un materiale inorganico, è possibile ottenere sistemi ibridi organici–inorganici con interessanti proprietà e vasti campi di applicazione. Sono un esempio delle “nanospugne” capaci di adsorbire efficacemente potenziali inquinanti. In questo contesto sono stati preparati, dei materiali ibridi “spugna” costituiti da unità ciclodestriniche e allosite e ancora un sistema ibrido HNT-Cucurbit[8]uril. Il primo possi…

Diastereoselective Synthesis of 2-Phenylselenenyl-1,3-anti-Diols and 2-Phenylselenenyl-1,3-anti-Azido-Alcohols via Hydroxy- and Azido-Selenenylation …

2005

A method to synthesize 2-phenylselenenyl-1,3-anti-diols and 2-phenyl- selenenyl-1,3-anti-azidoalcohols via hydroxy- or azido-selenenylation of trans-allylic alcohols is reported. Moreover, the first example of hydroxyl-selenenylation of an allylic azide is presented. Yields ranging from moderate to good and diastereomeric ratios up to 95:5 are achieved.

Investigation of the aqueous transmetalation of π-allylpalladium with indium salt: the use of the Pd(OAc)2–TPPTS catalyst

2005

pi-Allylpalladium complexes could be generated in water by the palladium(0) water soluble catalyst prepared in situ from palladium acetate and TPPTS. These complexes were transmetalated with indium to react with benzaldehyde. The aqueous solution of Pd(0)(TPPTS)(n) could be reused without deterioration of the catalyst in the first and second recycling. The system proved to be efficient with primary and secondary allylic substrates. The stereochemical outcome of the allylation through umpolung of allylpalladium, was also studied using models with a restraint conformation.

A Simple Procedure for Oxidation of Alcohols using [Bis(acetoxy)iodo]benzene and a Catalytic Amount of Bromide Ions in Ethyl Acetate

2015

Primary and secondary benzylic alcohols and secondary aliphatic alcohols were oxidized to the corresponding aldehydes and ketones by using [bis(acetoxy)iodo]benzene (BAIB) and a catalytic amount of bromide ions, from tetrabutylammonium bromide or KBr, in ethyl acetate. The catalytic role of the bromide ions was also highlighted in the oxidation of primary aliphatic alcohols and secondary allylic alcohols carried out in the presence of 1 mol% TEMPO.

Co-precipitation synthesis of Nd:YAG nano-powders: the effect of Nd dopant addition with thermal treatment

2007

Nanopowders of Yttrium Aluminium Garnet doped with neodymium ions were obtained by the co-precipitation method from the reaction of aluminium, yttrium and neodymium nitrate with ammonia. The amount of neodymium was selected in order to produce samples of nominal stoichiometry NdXY (3-X)Al5O12 (where X = 0.006, 0.012, 0.024, 0.048, 0.081, 0.096, 0.17, 0.19, 0.38, 0.54, and 0.72, respectively). After washing and drying, the hydroxide precursors were subjected to Thermo-Gravimetry and Differential Thermal Analysis experiments from room temperature up to 1500 °C, which showed the presence of exothermal events accompanying phase transformation phenomena. X-ray diffraction investigations conducte…

The Effect of Electronic Properties of Anodized and Hard Anodized Ti and Ti6Al4V on Their Reactivity in Simulated Body Fluid

2022

The electronic properties of barrier and porous layers on Ti and Ti6Al4V were studied. Barrier anodic oxides grown to 40 V on Ti and on Ti6Al4V are both n-type semiconductors with a band gap of 3.3 eV and 3.4 eV respectively, in agreement with the formation of amorphous TiO2. Anodizing to 200 V at 20 mA cm−2 in calcium acetate and β-glycerol phosphate disodium pentahydrate leads to the formation of Ca and P containing porous films with a photoelectrochemical behaviour dependent on the metallic substrate. A band gap of 3.2 eV and the flat band potential of −0.5 V vs Ag/AgCl were measured for the porous oxide on Ti, while optical transitions at 2.15 eV and a significantly more positive flat b…

SYNTHESIS AND EVALUATION OF CURCUMIN ANALOGUES AS NEURO-PROTECTIVE AGENTS FOR THE ALZHEIMER'S DISEASE

2013

The Alzheimer's disease (AD) is the most common form of senile dementia.1 The most important role in AD is played by the aggregation process of beta-amyloid peptide (Aß), responsible for the cytotoxic effects.2 In this context, the purpose of this study was to synthesize new dicarbonyl compounds 1 structurally related to curcumin3, with anti-aggregation activity against Aß.Parallel studies involve the synthesis of heterocyclic-based curcumin-like molecules that are currently under investigation by means of in silico protocols in order to rationalize the ligand-biological target interactions.

Chemical Characterization and Cytotoxic and Antioxidant Activity Evaluation of the Ethanol Extract from the Bulbs of Pancratium maritimun Collected i…

2023

P. maritimum L., belonging to the Amaryllidaceae family, is a species that grows on beaches and coastal sand dunes mainly on both sides of the Mediterranean Sea and Black Sea, the Middle East, and up to the Caucasus region. It has been largely investigated due to its several interesting biological properties. With the aim of providing new insights into the phytochemistry and pharmacology of this species, the ethanolic extract of the bulbs from a local accession, not previously studied, growing in Sicily (Italy), was investigated. This chemical analysis, performed by mono- and bi-dimensional NMR spectroscopy, as well as LC-DAD-MSn, allowed to identify several alkaloids, three of which were n…