Search results for "Esteri"

Mecanismos de acción citotóxica producidos por la esterigmatocistina en las células sh-sy5y de neuroblastoma humano

2021

En la presente Tesis Doctoral se ha llevado a cabo la evaluación in vitro de los efectos producidos por la micotoxina esterigmatocistina (STE) en células de mamífero. El conocimiento de los efectos tóxicos y exposición a dicha micotoxina permite una mejor caracterización de los riesgos de la población. Se ha evaluado la citotoxicidad individual de la STE en células de neuroblastoma (SH-SY5Y) y de carcinoma hepatocelular humano (HepG2), mostrando valores de IC50 únicamente en las células SH-SY5Y. Debido a que la exposición simultánea o secuencial a múltiples micotoxinas podría dar lugar a efectos adversos sobre la salud del consumidor, se ha evaluado la citotoxicidad combinada de la STE con …

IBRIDI FORMATI DA NANOTUBI DI CARBONIO A PARETE MULTIPLA E ESTERI FOSFORICI: PROPRIETA’ E STUDI STRUTTURALI

2012

Nel corso degli ultimi anni i nanotubi di carbonio in virtù delle loro proprietà fisiche, chimiche e meccaniche sono diventati tra i più promettenti materiali per la realizzazione di congegni a livello nanometrico. I CNT trovano numerose applicazioni nel campo, della nanoelettronica, nella costruzione di materiali ad elevata conducibilità elettrica ed elevata resistenza meccanica,2 e vengono, anche, impiegati come agenti di rinforzo dispersi in una matrice polimerica.3 Problema principale di questi materiali è che essi risultano scarsamente solubili in ambiente acquoso e in solventi organici, a causa delle forti forze attrattive di van der Waals che esistono tra le superfici dei CNT, che li…

Interazioni non covalenti tra esteri fosforici e nanotubi di carbonio a parete multipla

2010

Fin dal 1991, quando Iijima li osservò per la prima volta, i nanotubi di carbonio (CNT) sono diventati oggetto d'interesse scientifico, in virtù delle loro proprietà fisiche, chimiche e meccaniche. Un impiego molto interessante riguarda l'aumento di stabilità di matrici polimeriche. I nanocompositi polimerici, in cui sono presenti percentuali molto basse di CNT (2.5%), presentano enormi miglioramenti nelle caratteristiche termomeccaniche, nella resistenza al calore e nella conduttività elettrica. C'è, però, un impedimento fondamentale a tutte le applicazioni che riguarda l'insolubilità intrinseca dei CNT nei solventi. La funzionalizzazione sia essa covalente che non è un espediente per ovvi…

Microwave-Assisted Esterification of Tall Oil Fatty Acids with Methanol Using Lignin-Based Solid Catalyst

2016

During alkaline pulping significant amounts of lignin, carbohydrates (mostly hemicelluloses), and extractives (tall oil soap and turpentine) are removed from wood feedstock. In this study, the catalytic esterification of fatty acids in tall oil with methanol to produce fatty acid methyl esters under microwave irradiation was performed at 100 °C for 10–60 min. A novel heterogeneous acid catalyst tested for this purpose was synthesized from the hardwood alkali lignin that was precipitated by acidification from the black liquor from soda-AQ pulping. The comparative reaction data were obtained by using other solid catalysts, Amberlyst 15, and p-toluenesulfonic acid. The results showed the highe…

CCDC 1523875: Experimental Crystal Structure Determination

2017

UDARID : ethyl N-benzoylalaninate Space Group: P212121, Cell: a 5.2938(2)Å b 12.1920(8)Å c 17.7130(4)Å, α 90° β 90° γ 90° Work published 2017 via Cambridge Crystallographic Data Centre.

Effect of lithium ions on the catalytic efficiency of calcium oxide as a nanocatalyst for the transesterification of lard oil

2019

The present work encompasses the effect of Li+ ions on CaO nanoparticles for the transesterification of lard oil. The modification of CaO nanoparticles was achieved by the impregnation of different molar ratios of lithium hydroxide. Later, each catalyst was screened for the catalytic conversion of lard oil to a fatty acid methyl ester (FAME). The nanocatalyst CaO–0.5LiOH (1 : 0.5 molar ratio) showed the best conversion rate for FAME. The synthesized nanocatalyst was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) analysis, and Hammett indicato…

Rypsimetyyliesterin tuotantopotentiaali, energiataseet ja kannattavuuslaskelma maatilamittakaavaiselle valmistukselle

2007

Highly Syndiotactic or Isotactic Polyhydroxyalkanoates by Ligand-Controlled Yttrium-Catalyzed Stereoselective Ring-Opening Polymerization of Function…

2017

International audience; Reported herein is the first stereoselective controlled ROP of a specific family of racemic functional β-lactones, namely 4-alkoxymethylene-β-propiolactones (BPL(OR) s). This process is catalyzed by an yttrium complex stabilized by a nonchiral tetradentate amino alkoxy bisphenolate ligand _ONOO(R'2) ₍2-) , which features both a good activity and a high degree of control over the molar masses of the resulting functional poly(3-hydroxyalkanoate)s. A simple modification of the R' substituents in ortho and para position on the ligand platform allows for a complete reversal from virtually pure syndioselectivity (Ps up to 0.91 with R'=cumyl) to very high isoselectivity (Pi…

Influenza di parametri fermentativi sulla composizione di vini Catarratto

2011

Biodiesel via in situ wet microalgae biotransformation: Zwitter-type ionic liquid supported extraction and transesterification

2017

The production of biodiesel derived from microalgae is among the most forthcoming technologies that provide an ecologic alternative to fossil fuels. Herein, a method was developed that enables the direct extraction and conversion of algal oil to biodiesel without prior isolation. The reaction occurs in aqueous media catalyzed by immobilized Candida antarctica lipase B (Novozyme 435). Zwitter-type ionic liquids were used as cocatalyst to improve the selectivity and reactivity of the enzyme. In a model reaction with sunflower oil, 64% biodiesel was obtained. Applying this method to a slurry of whole-cell Chlorella zof ingiensis in water resulted in 74.8% of lipid extraction, with 27.7% biotra…