Steering the magnetic properties of Ni/NiO/CoO core-shell nanoparticle films: The role of core-shell interface versus interparticle interactions

Supported core-shell Ni/NiO/CoO nanoparticle (NP) films were obtained by deposition of preformed and mass-selected Ni NPs on a buffer layer of CoO, followed by a top CoO layer. The resulting NPs have core/shell morphology, with a McKay icosahedral Ni core and a partially crystalline CoO shell. X-ray photoelectron spectroscopy evidenced the presence of a thin NiO layer, which was shown to be between the Ni core and the CoO shell by elemental TEM mapping. CoO and NiO shells with different thickness values were obtained, allowing us to investigate the evolution of the magnetic properties of the NP assemblies as a function of the oxide shell thickness. Both exchange-coupling and magnetostatic interactions significantly contribute to the magnetic behavior of Ni/NiO/CoO NP films. After the Ni/NiO/CoO NPs are cooled in a weak magnetic field, they have blocking temperature higher than room temperature because of strong magnetostatic interactions, which support the formation of a spin-glass-like state below similar to 250 K. Exchange coupling dominates the magnetic behavior after the NPs are cooled in a strong magnetic field. The exchange bias (EB) is in the 0.17-2.35 kOe range and strongly depends on the CoO thickness (0.4-2.7 nm), showing the onset of the EB at the few-nanometer scale. The switching field distribution showed that the EB opposes the magnetization reversal from the direction along the cooling field but it does not significantly ease the opposite process. The EB depends on t(CoO) only for t(NiO) <= 0.5 nm, but when NiO is 0.7 nm thick it strongly interacts with CoO and a large increase of the EB and coercivity is observed

Structure and Morphology of Silver Nanoparticles on the (111) Surface of Cerium Oxide

The structure of Ag nanoparticles of different size, supported on the cerium oxide (111) surface, was investigated by X-ray absorption fine structure at the Ag K-edge. The results of the data analysis in the near and extended energy range are interpreted with the help of the results obtained by X-ray photoelectron spectroscopy and scanning tunneling microscopy measurements and allow to obtain a detailed atomic scale description of the model system investigated. The Ag nanoparticles have an average size of a few tens of angstroms, which increases with increasing deposited Ag amount. The nanoparticles show a slight tendency to nucleate at the step edges between different cerium oxide layers and they have a face centered cubic structure with an Ag-Ag interatomic distance contracted by 3-4% with respect to the bulk value. The interatomic distance contraction is mainly ascribed to dimensionality induced effects, while epitaxial effects have a minor role. The presence of Ag-O bonds at the interface between the nanoparticles and the supporting oxide is also detected. The Ag-O interatomic distance decreases with decreasing nanoparticle size

RELATIONSHIP BETWEEN SERUM URIC ACID AND METABOLIC SYNDROME IN THE BRISIGHELLA HEART STUDY COHORT

Objective: Classically correlated with pathologies such as kidney stone and gout, today serum uric acid (SUA) seem to play a pivotal role in the cardiovascular disease risk. SUA is also strongly related to metabolic syndrome (MS) and its components. The aim of our study was to evaluate the SUA cut-off associated to the highest probability to detect a MS Design and method: We selected from the general database of the Brisighella Heart Study a sample of non-pharmacologically treated adult subjects, in primary prevention for cardiovascular disease, without known allergic nor rheumatological disease, not assuming antioxidant dietary supplements, visited during the same population survey. The SUA cut-off associated to the highest probability to detect a MS was investigated creating specific receiver operating characteristic (ROC) curves. Results: In our study median SUA levels were significantly higher in men (5,1 mg/dL) than in women (3,6 mg/dL) (p &lt; 0.05). Splitting our cohort in 2 groups on the basis of SUA medians,we obtained 2 very different populations: if SUA levels were over the median the main cardiovasculardisease risk factors means were higher, while HDL cholesterol and apolipoprotein A1 levels were lower; these patients were more frequently affected by MS (58,5%) and hypertension (52,7%) than those with SUA levels under the median. The ROC curves showed that the SUA levels was a predictive test for the identification of those people affected by MS, with an AUC similar between men and women (6,6 vs 6,8, respectively); the cut off, by the way, were 5,75 mg/dL in men and 3,95 mg/dL in women. SUA levels seems to be the main determinant of MS both in men (OR = 1,66; 95%CI 1,23 – 1,99) and women (OR = 1,63; 95%CI 1,19 – 1,97). Conclusions: In our cohort SUA is strongly related to MS diagnosis, also for level lower than those usually considered normal

Expeditious and practical synthesis of tertiary alcohols from esters enabled by highly polarized organometallic compounds under aerobic conditions in Deep Eutectic Solvents or bulk water

An efficient protocol was developed for the synthesis of tertiary alcohols via nucleophilic addition of organometallic compounds of s-block elements (Grignard and organolithium reagents) to esters performed in the biodegradable choline chloride/urea eutectic mixture or in water. This approach displays a broad substrate scope, with the addition reaction proceeding quickly (20 s reaction time) and cleanly, at ambient temperature and under air, straightforwardly furnishing the expected tertiary alcohols in yields of up to 98%. The practicability of the method is exemplified by the sustainable synthesis of some representative S-trityl-L-cysteine derivatives, which are a potent class of Eg5 inhibitors, also via telescoped one-pot processes

Relationship between serum uric acid and electrocardiographic alterations in a large sample of general population: data from the Brisighella Heart Study.

Introduction: Serum uric acid (SUA) may contribute to the increased cardiovascular damage through direct injury to the endothelium and alteration of cardiovascular function. Aim: To evaluate the association of SUA with the presence of the most recurrent electrographic alterations and with the length of the main ECG intervals in a large sample of general population. Methods: For this study, on the database of the Brisighella Heart Study, we evaluated the available data of 790 men and 849 women, excluding subjects affected by gout or taking antihyperuricemic agents, those taking drug increasing the QT interval and those using beta-blockers or non-dihydropyridine calcium channel blockers at the moment of the ECG registration. Multiple ascending stepwise regression analyses were carried out to determine the independent predictors of the predefined ECG alterations. Results: The prevalence of predefined ECG alterations was comparable between genders, with the exception of sinus bradicardia, left-anterior fascicular block, atrio-ventricular blocks and left ventricular hypertrophy (LVH), which appeared to be more frequent in men. The multivariate analysis revealed that SUA was associated to ischaemic alterations, LVH, sinus tachycardia and tachyarrhytmias. Age was associated to all evaluated ECG alterations beyond sinus tachycardia and LVH. Male sex was associated to sinus bradicardia, atrio-ventricular blocks, anterior-left fascicular block and LVH. Blood pressure was associated to different ECG alterations, but with clinically relevant OR with ischaemic alterations and LVH. Conclusion: SUA level is related the prevalence of both organic and rhythm ECG alterations in a wide sample of general population

Surface structure of phosphorus-terminated GaP(001)-(2×1)

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