Microscopic energy flows in disordered Ising spin systems

An efficient microcanonical dynamics has been recently introduced for Ising spin models embedded in a generic connected graph even in the presence of disorder i.e. with the spin couplings chosen from a random distribution. Such a dynamics allows a coherent definition of local temperatures also when open boundaries are coupled to thermostats, imposing an energy flow. Within this framework, here we introduce a consistent definition for local energy currents and we study their dependence on the disorder. In the linear response regime, when the global gradient between thermostats is small, we also define local conductivities following a Fourier dicretized picture. Then, we work out a linearized "mean-field approximation", where local conductivities are supposed to depend on local couplings and temperatures only. We compare the approximated currents with the exact results of the nonlinear system, showing the reliability range of the mean-field approach, which proves very good at high temperatures and not so efficient in the critical region. In the numerical studies we focus on the disordered cylinder but our results could be extended to an arbitrary, disordered spin model on a generic discrete structures.Comment: 12 pages, 6 figure

Elevated stearoyl-CoA desaturase in brains of patients with Alzheimer\u27s disease

The molecular bases of Alzheimer\u27s disease (AD) remain unclear. We used a lipidomic approach to identify lipid abnormalities in the brains of subjects with AD (N = 37) compared to age-matched controls (N = 17). The analyses revealed statistically detectable elevations in levels of non-esterified monounsaturated fatty acids (MUFAs) and mead acid (20:3n-9) in mid-frontal cortex, temporal cortex and hippocampus of AD patients. Further studies showed that brain mRNAs encoding for isoforms of the rate-limiting enzyme in MUFAs biosynthesis, stearoyl-CoA desaturase (SCD-1, SCD-5a and SCD-5b), were elevated in subjects with AD. The monounsaturated/saturated fatty acid ratio (\u27desaturation index\u27)--displayed a strong negative correlation with measures of cognition: the Mini Mental State Examination test (r = -0.80; P = 0.0001) and the Boston Naming test (r = -0.57; P = 0.0071). Our results reveal a previously unrecognized role for the lipogenic enzyme SCD in AD

Effect of rMnSOD on sodium reabsorption in renal proximal tubule in Ochratoxin A - treated rats

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium that represent toxic real threat for human beings and animal health. In this study we evaluated the effect of a new recombinant mitochondrial manganese containing superoxide dismutase (rMnSOD) on oxidative stress and on the alterations of fluid reabsorption in renal proximal tubule (PT) as possible causes of OTA nephrotoxicity. Finally, we have measured the concentration of O2 - in the kidney through dihydroethidium assay (DHE) and nitric oxide (NO) concentration through nitrites and nitrates assay. Male Sprague Dawley rats weighing 120-150 g were treated for 14 days by gavage, as follows: Control group, 12 rats received a corresponding amount of saline solution (including 10% DMSO); rMnSOD group, 12 rats treated with rMnSOD (10 μg/kg bw); OTA group, 12 rats treated with OTA (0,5 mg/Kg bw) dissolved in 10% DMSO and then scaled to required volume with corn oil; rMnSOD + OTA, 12 rats treated with rMnSOD (10 μg /kg bw) plus OTA (0,5 mg/Kg bw). Our results have shown that rMnSOD restores the alteration of reabsorption in PT in rats treated with OTA plus rMnSOD, probably through the response to pressure natriuresis, where nitric oxide plays a key role. Moreover, rMnSOD prevents the nephrotoxicity induced by OTA probably restoring the balance between superoxide and NO that is most probably the cause of hypertension and renal functional alterations through the inhibition of NO synthase. In conclusion these data provide important information for understanding of mechanism of toxic action of OTA

Corrosion behavior of friction stir welded lap joints of AA6061-T6 aluminum alloy

In this work, the corrosion behaviors of friction-stir lap welding of 6061-T6 Al-alloy are studied. The friction-stir lap welding was performed under different welding conditions (rotation speed and welding speed). The corrosion behavior of the parent alloy, the weld nugget zone (WNZ), and the heat affected zone (HAZ) of each welded sample working as an electrode, were investigated by the Tafel polarization test in 3.5 wt. (%) NaCl at ambient temperature. The morphology of the corroded surface of each region was analyzed by scanning electron microscopy together with energy dispersive spectroscopy (SEM-EDS). The results showed that the corrosion resistance of the parent alloy was better than the WNZ and the HAZ in both welding conditions. Localized pit dissolution and intergranular corrosion were the dominant corrosion types observed in the parent alloy, WNZ, and HAZ. The parent alloy, WNZ, and HAZ exhibited similar corrosion potentials (Ecorr) after T6 heat treatment. This treatment had a better effect on the corrosion resistance of the welded regions than the parent alloy

L’utilizzo del lembo di SMAS per ricostruzioni della loggia parotidea

Lo scopo dello studio è stato quello di valutare i benefici della ricostruzione con lembo di SMAS nei pazienti affetti da neoplasie benigne della parotide e sottoposti a parotidectomia superficiale. Abbiamo condotto uno studio retrospettivo su 123 pazienti affetti da neoplasie benigne della ghiandola parotide ricoverati presso il Nostro istituto tra il Marzo 1997 e Marzo 2010. Tutti i pazienti arruolati sono stati sottoposti a parotidectomia superficiale. Il Nostro campione è stato diviso in due gruppi in base alla esecuzione (Gruppo 2) o no (Gruppo 1) di ricostruzione con lembo di SMAS dopo la parotidectomia superficiale. La ricostruzione con lembo di SMAS è stata eseguita in 64 pazienti. Un test chi quadro è stato utilizzato per valutare le differenze statistiche tra i due gruppi. Il livello di significatività statistica scelto è stato di p 0,05] , 8,47% vs 4,68% [P > 0,05, 5,08% vs 0,00%). La paralisi transitoria del facciale, la fistola, la depressione della cute e la sindrome di Frey sono significativamente più frequenti nei pazienti non ricostruiti con lembo di SMAS (10,16% vs 3,125% [P < 0,05], 13,55% vs 3,125% [P < 0,05] , 13,55% vs 3,125% [P < 0,05], 20,33% vs 0% [P < 0,05], rispettivamente). Il lembo di SMAS è capace di ridurre le complicanze funzionali ed estetiche che si verificano dopo la rimozione di un tumore benigno della parotide mediante parotidectomia superficiale, tra queste, riduce il verificarsi della sindrome di Frey

Elevated Stearoyl-CoA Desaturase in Brains of Patients with Alzheimer's Disease

The molecular bases of Alzheimer's disease (AD) remain unclear. We used a lipidomic approach to identify lipid abnormalities in the brains of subjects with AD (N = 37) compared to age-matched controls (N = 17). The analyses revealed statistically detectable elevations in levels of non-esterified monounsaturated fatty acids (MUFAs) and mead acid (20:3n-9) in mid-frontal cortex, temporal cortex and hippocampus of AD patients. Further studies showed that brain mRNAs encoding for isoforms of the rate-limiting enzyme in MUFAs biosynthesis, stearoyl-CoA desaturase (SCD-1, SCD-5a and SCD-5b), were elevated in subjects with AD. The monounsaturated/saturated fatty acid ratio (‘desaturation index’) – displayed a strong negative correlation with measures of cognition: the Mini Mental State Examination test (r = −0.80; P = 0.0001) and the Boston Naming test (r = −0.57; P = 0.0071). Our results reveal a previously unrecognized role for the lipogenic enzyme SCD in AD

Dietary and Behavioral Interventions Protect against Age Related Activation of Caspase Cascades in the Canine Brain

Lifestyle interventions such as diet, exercise, and cognitive training represent a quietly emerging revolution in the modern approach to counteracting age-related declines in brain health. Previous studies in our laboratory have shown that long-term dietary supplementation with antioxidants and mitochondrial cofactors (AOX) or behavioral enrichment with social, cognitive, and exercise components (ENR), can effectively improve cognitive performance and reduce brain pathology of aged canines, including oxidative damage and Aβ accumulation. In this study, we build on and extend our previous findings by investigating if the interventions reduce caspase activation and ceramide accumulation in the aged frontal cortex, since caspase activation and ceramide accumulation are common convergence points for oxidative damage and Aβ, among other factors associated with the aged and AD brain. Aged beagles were placed into one of four treatment groups: CON – control environment/control diet, AOX– control environment/antioxidant diet, ENR – enriched environment/control diet, AOX/ENR– enriched environment/antioxidant diet for 2.8 years. Following behavioral testing, brains were removed and frontal cortices were analyzed to monitor levels of active caspase 3, active caspase 9 and their respective cleavage products such as tau and semaphorin7a, and ceramides. Our results show that levels of activated caspase-3 were reduced by ENR and AOX interventions with the largest reduction occurring with combined AOX/ENR group. Further, reductions in caspase-3 correlated with reduced errors in a reversal learning task, which depends on frontal cortex function. In addition, animals treated with an AOX arm showed reduced numbers of cells expressing active caspase 9 or its cleavage product semaphorin 7A, while ENR (but not AOX) reduced ceramide levels. Overall, these data demonstrate that lifestyle interventions curtail activation of pro-degenerative pathways to improve cellular health and are the first to show that lifestyle interventions can regulate caspase pathways in a higher animal model of aging