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Size-selected iron oxide nanoclusters are outstanding candidates for technological-oriented applications due to their high efficiency-to-cost ratio. However, despite many theoretical studies, experimental works on their oxidation mechanism are still limited to gas-phase clusters. Herein we investigate the oxidation of graphene-supported size-selected Fen clusters by means of high-resolution X-ray Photoelectron Spectroscopy. We show a dependency of the core electron Fe 2p3/2 binding energy of metallic and oxidized clusters on the cluster size. Binding energies are also linked to chemical reactivity through the asymmetry parameter which is related to electron density of states at the Fermi energy. Upon oxidation, iron atoms in clusters reach the oxidation state Fe(II) and the absence of other oxidation states indicates a Fe-to-O ratio close to 1:1, in agreement with previous theoretical calculations and gas-phase experiments. Such knowledge can provide a basis for a better understanding of the behavior of iron oxide nanoclusters as supported catalysts.
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The possibility of depositing precisely mass-selected Ag clusters (Ag1, Ag3, and Ag7) on Ru(0001) was instrumental in determining the importance of the in-plane coordination number (CN) and allowed us to establish a linear dependence of the Ag 3d5/2 core-level shift on CN. The fast cluster surface diffusion at room temperature, caused by the low interaction between silver and ruthenium, leads to the formation of islands with a low degree of ordering, as evidenced by the high density of low-coordinated atomic configurations, in particular CN = 4 and 5. On the contrary, islands formed upon Ag7 deposition show a higher density of atoms with CN = 6, thus indicating the formation of islands with a close-packed atomic arrangement. This combined experimental and theoretical approach, when applied to clusters of different elements, offers the perspective to reveal nonequivalent local configurations in two-dimensional (2D) materials grown using different building blocks, with potential implications in understanding electronic and reactivity properties at the atomic level.
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Intraplaque hemorrhage (IPH) is one of the main factors involved in atherosclerotic plaque (AP) instability. Its recognition is crucial for the correct staging and management of patients with carotid artery plaques to limit ischemic stroke. Imaging plays a crucial role in identifying IPH, even if the great variability of intraplaque vascularization and the limitations of our current imaging technologies make it difficult. The intent of this review is to give a general overview of the main features of intraplaque vascularization and IPH on Ultrasound (US), Computed Tomography (CT), Magnetic Resonance (MR) and Nuclear Medicine, and a brief description on the future prospectives.
Assuntos
Estenose das Carótidas/diagnóstico por imagem , Hemorragia/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Tomografia Computadorizada por Raios X , UltrassonografiaRESUMO
Here we report a giant, completely reversible magneto-electric coupling of 100 nm polycrystalline Co layer in contact with ZnO nanorods. When the sample is under an applied bias of ±2 V, the Co magnetic coercivity is reduced by a factor 5 from the un-poled case, with additionally a reduction of total magnetic moment in Co. Taking into account the chemical properties of ZnO nanorods measured by X-rays absorption near edge spectroscopy under bias, we conclude that these macroscopic effects on the magnetic response of the Co layer are due to the microstructure and the strong strain-driven magneto-electric coupling induced by the ZnO nanorods, whose nanostructuration maximizes the piezoelectric response under bias.
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BACKGROUND: Parkinson's disease (PD) occurs more frequently in men than in women and a higher risk for PD development in males compared with females has been hypothesized, suggesting gender may be a significant factor in the development and progression of parkinsonism. To date, gender differences in non-motor symptoms are under-reported. OBJECTIVE: To assess gender differences in motor and non-motor symptoms among Sardinian PD patients. METHODS: One hundred fifty-six (91 male and 65 female) consecutive Sardinian PD outpatients were included in this analysis. Modified Hoehn and Yahr scale and UPDRS were used to assess motor symptoms, while non-motor disturbances were evaluated with the non-motor symptoms scale (NMSS). Presence of depression, anxiety and other iatrogenic behavioral disorders was also investigated. In order to determine how gender differences could be specific to PD, 132 age-matched normal controls were assessed with the NMSS. RESULTS: Women were more likely than men to present with tremor as initial symptom (p<.025) and worse UPDRS instability score (p<.02). NMSS score in females was significantly higher than that in males (p<.018). A significantly higher severity in cardiovascular (p<0.002), sleep/fatigue (p<.018) and mood/apathy (p<.001) domains was observed in female PD patients, while the sexual dysfunction domain was reported with a significantly higher score in male patients (p<.017). Fatigue (p<.03), lack of motivation (p<.015) and sadness (p<.009) were observed significantly more frequent in females, while altered interest in sex was noted as more common in males (p<.001). Frequency of depression (p<.011) and anxiety (p<.001) was significantly higher in females, while male patients had increased frequency of compulsive sexual behaviors (p<.05). There was a significantly higher frequency of non-motor symptoms in eight domains in both male and female PD patients compared with controls (p<.001, for all comparisons, with the exception of urinary disturbances in females: p<.004). Only sexual dysfunctions were not significantly higher in male and female PD patients compared with controls. DISCUSSION: The present study highlights the role of gender differences associated with the occurrence of motor and non-motor disorders and our findings indicate that spectrum and severity of non-motor symptoms may present with different gender distribution in PD patients, suggesting a possible sex-related effect.