On the importance of anandamide structural features for its interactions with DPPC bilayers: effects on PLA2 activity

The acylethanolamide anandamide (AEA) occurs in a variety of mammalian tissues and, as a result of its action on cannabinoid receptors, exhibits several cannabimimetic activities. Moreover, some of its effects are mediated through interaction with an ion channel-type vanilloid receptor. However, the chemical features of AEA suggest that some of its biological effects could be related to physical interactions with the lipidic part of the membrane. The present work studies the effect of AEA-induced structural modifications of the dipalmitoylphosphatidylcholine (DPPC) bilayer on phospholipase A2 (PLA2) activity, which is strictly dependent on lipid bilayer features. This study, performed by 2-dimethylamino-(6-lauroyl)-naphthalene fluorescence, demonstrates that the effect of AEA on PLA2 activity is concentration-dependent. In fact, at low AEA/DPPC molar ratios (from R = 0.001 to R = 0.04), there is an increase of the enzymatic activity, which is completely inhibited for R = 0.1. X-ray diffraction data indicate that the AEA affects DPPC membrane structural properties in a concentration-dependent manner. Because the biphasic effect of increasing AEA concentrations on PLA2 activity is related to the induced modifications of membrane bilayer structural properties, we suggest that AEA-phospholipid interactions may be important to produce, at least in part, some of the similarly biphasic responses of some physiological activities to increasing concentrations of AEA

Analisi di risposta sismica locale di una villa Seicentesca presso Grottammare (AP)

Nella recente normativa vigente sulle costruzioni (NTC 2018) emerge un'attenzione al fatto che la pericolosità sismica di base vari in funzione delle caratteristiche morfologiche e stratigrafiche che determinano la risposta sismica locale. Nella seguente tesi è stato studiato il comportamento sotto sisma di una villa di interesse storico, in prospettiva di una eventuale ristrutturazione. Villa Azzolino, situata nella cittadina di Grottammare (AP), è una costruzione risalente alla seconda metà del XVII secolo ed uno tra i pochi edifici storici della zona ad aver mantenuto il suo impianto originario. È stata eseguita una campagna di indagine geofisica con tecniche di sismica attiva e passiva con lo scopo di ricavare il modello dinamico della struttura e il modello del terreno. È stata poi condotta un'analisi di risposta sismica locale ottenendo lo spettro di risposta elastico in accelerazione semplificato e non semplificato. Accoppiando il modello dinamico della struttura con lo spettro di risposta del sito, si è riscontrato che la villa si colloca nel plateau dello spettro, quindi a periodi per i quali l'accelerazione attesa sulla struttura è massima. Questo non depone a favore della sua sicurezza, considerando anche i problemi relativi alla mancata manutenzione e allo stato attuale dell'edificio. In ultimo sono state accennate delle tecniche ingegneristiche di rinforzo per gli edifici in muratura utili in caso di ristrutturazione dell'edificio storico

EFFECT OF N-ACYLETHANOLAMIDES ON PLASMA LIPID PEROXIDATION AND PARAOXONASE ACTIVITY: AN IN VITRO STUDY

N-acylethanolamides (NAEs) are naturally occurring hydrophobic molecules, present in mammalian tissues and biological fluids, such as plasma. Previous studies showed that some of these molecules have protective properties against oxidative stress in some cell models. The present study was designed to determine whether NAEs, differing for acyl chain length and unsaturation, can have a protective effect on the oxidative susceptibility of plasma lipids, that is considered a factor contributing to atherogenic risk. To study the effect of three different NAEs on free-radical induced damage of plasma lipids, conjugated dienes and lipid hydroperoxides formation was investigated by incubating unfractionated plasma with radical generators (Cu2+ and/or AAPH). Moreover, the effect of these NAEs on the in vitro induced oxidative degradation of PON1 activity was measured, in unfractionated plasma. PON1, an enzyme associated with plasma high density lipoproteins, plays an important role against oxidative damage of lipoproteins and in protection against atherosclerosis. Results obtained demonstrated that the NAEs used oleoylethanolamide, palmitoylethanolamide and anandamide) elicited a significant protection against both AAPH and copper-induced plasma lipid hydroperoxides increase or oxidative decrease of PON1 activity. The protective effect was shown also on the conjugated dienes formation induced by incubation of diluted plasma with CuSO4. Among the three NAEs used, the largest protective effect was shown by 1 µM anandamide (AEA) that induced a 32.6% decrease of lipid hydroperoxides concentration, with respect to control sample, in undiluted plasma incubated with 20 µM CuSO4. Our results suggest a possible protective role of NAEs in the pathogenesis of diseases associated with oxidative stress

EFFECT OF N-ACYLETHANOLAMIDES ON PLASMA LIPID\ud PEROXIDATION AND PARAOXONASE ACTIVITY: AN IN VITRO STUDY

N-acylethanolamides (NAEs) are naturally occurring hydrophobic molecules, present in mammalian tissues and biological fluids, such as plasma. Previous studies showed\ud that some of these molecules have protective properties against oxidative stress in some cell models. The present study was designed to determine whether NAEs, differing for acyl chain length and unsaturation, can have a protective effect on the oxidative susceptibility of plasma lipids, that is considered a factor contributing to atherogenic risk. To study the effect of three different NAEs on free-radical induced damage of plasma lipids, conjugated dienes and lipid hydroperoxides formation was investigated by incubating unfractionated plasma with radical generators (Cu2+ and/or AAPH). Moreover, the effect of these NAEs on the in vitro induced oxidative degradation of PON1 activity was measured, in unfractionated plasma. PON1, an enzyme associated with plasma high density lipoproteins, plays an important role against oxidative damage of lipoproteins and in protection against atherosclerosis.\ud Results obtained demonstrated that the NAEs used oleoylethanolamide, palmitoylethanolamide and anandamide) elicited a significant protection against both AAPH and copper-induced plasma lipid hydroperoxides increase or oxidative decrease of PON1 activity. The protective effect was shown also on the conjugated dienes formation induced by incubation of diluted plasma with CuSO4. Among the three NAEs used, the largest protective effect was shown by 1 µM anandamide (AEA) that induced a 32.6% decrease of lipid hydroperoxides concentration, with respect to control sample, in undiluted plasma incubated with 20 µM CuSO4.\ud Our results suggest a possible protective role of NAEs in the pathogenesis of diseases associated with oxidative stress

Fluorescence studies of the interactions of ubiquinol-10 with liposomes.

Ubiquinone-10 plays a central role in energy production and its reduced form, ubiquinol-10 is also capable of acting as a potent radical scavenging antioxidant against membrane lipid peroxidation. Efficiency of this protection depends mostly on its localization in lipid bilayer. The intrinsic fluorescence of ubiquinol-10 and of the exogenous probe, Laurdan, has been used to determine the location of ubiquinol-10 in unilamellar liposomes of egg phosphatidylcholine (EggPC) and dimyristoyl phosphatidylcholine. Laurdan fluorescence moiety is positioned at the hydrophilic-hydrophobic interface of the phospholipid bilayer and its parameters reflect the membrane polarity and microheterogeneity, which we have used to explore the coexistence of microdomains with distinct physical properties. In liquid-crystalline bilayers ubiquinol has a short fluorescence lifetime (0.4 ns) and a high steady-state anisotropy. In a concentration-dependent manner, ubiquinol-10 influences the Laurdan excitation, emission and generalized polarization measurements. In EggPC liposomes ubiquinol-10 induces a decrease in membrane water mobility near the probe, while in dimyristoyl liposomes a decrease in the membrane water content was found. Moreover the presence of ubiquinol results in the formation of coexisting phospholipid domains of gel and liquid-crystalline phases. The results indicate that ubiquinol-10 molecules are mainly located at the polar-lipid interface, inducing changes in the physico-chemical properties of the bilayer microenvironment

Genetic Algorithms for Satellite Scheduling Problems

Recently there has been a growing interest in mission operations scheduling problem. The problem, in a variety of formulations, arises in management of satellite/space missions requiring efficient allocation of user requests to make possible the communication between operations teams and spacecraft systems. Not only large space agencies, such as ESA (European Space Agency) and NASA, but also smaller research institutions and universities can establish nowadays their satellite mission, and thus need intelligent systems to automate the allocation of ground station services to space missions. In this paper, we present some relevant formulations of the satellite scheduling viewed as a family of problems and identify various forms of optimization objectives. The main complexities, due highly constrained nature, windows accessibility and visibility, multi-objectives and conflicting objectives are examined. Then, we discuss the resolution of the problem through different heuristic methods. In particular, we focus on the version of ground station scheduling, for which we present computational results obtained with Genetic Algorithms using the STK simulation toolkit

On the importance of anandamide structural features for its interactions with dipalmitoylphospahtidylcholine bilayers: effects on PLA2 activity

The acylethanolamide anandamide (AEA) occurs in a variety of mammalian tissues and, as a result of its action on cannabinoid receptors, exhibits several cannabimimetic activities. Moreover, some of its effects are mediated through interaction with an ion channel-type vanilloid receptor. However, the chemical features of AEA suggest that some of its biological effects could be related to physical interactions with the lipidic part of the membrane. The present work studies the effect of AEA-induced structural modifications of the dipalmitoylphosphatidylcholine (DPPC) bilayer on phospholipase A2 (PLA2) activity, which is strictly dependent on lipid bilayer features. This study, performed by 2-dimethylamino-(6-lauroyl)-naphthalene fluorescence, demonstrates that the effect of AEA on PLA2 activity is concentration-dependent. In fact, at low AEA/DPPC molar ratios (from R = 0.001 to R = 0.04), there is an increase of the enzymatic activity, which is completely inhibited for R = 0.1. X-ray diffraction data indicate that the AEA affects DPPC membrane structural properties in a concentration-dependent manner. Because the biphasic effect of increasing AEA concentrations on PLA2 activity is related to the induced modifications of membrane bilayer structural properties, we suggest that AEA-phospholipid interactions may be important to produce, at least in part, some of the similarly biphasic responses of some physiological activities to increasing concentrations of AEA