2,296 research outputs found

    Tuning the potential drop at graphene/protic ionic liquid interface by molecular structure engineering

    Get PDF
    Ionic liquids (ILs) have been extensively employed in many applications involving interfaces with carbon-based electrodes, such as energy storage devices (batteries or supercapacitors) or electrocatalytic devices, where the way each ion of the IL interacts with the electrode has a strong impact on the overall performance of the device. For instance, the amount of potential difference between the electrode and the bulk of the IL is highly sensitive to the IL composition and it is directly related to the device capacitance. The selection of the most suited pair of ions often proceeds by time-consuming and costly trial-and-error approaches. It is necessary to understand the atomistic features of the interface to determine the effect of each ion on the potential drop. By classical molecular dynamics simulations, we show that it is possible to quickly infer the interface potential arising at the carbon electrode by carefully inspecting the molecular structure of the IL. The ion orientation at the interface is, in fact, determined by the distribution of charges within the molecules. Depending on where charges are located, ions can either lie flat or perpendicular to the interface to minimize the surface energy. The interface potential is found to be mainly determined by ion-ion interactions dictating the interface energy minimization process, whereas ion-electrode interactions are found to enforce higher ordering and charge layers stacking but not to induce selective adsorption of an ion over the other

    Ab initio Study of Misfit Dislocations at the SiC/Si(001) Interface

    Full text link
    The high lattice mismatched SiC/Si(001) interface was investigated by means of combined classical and ab initio molecular dynamics. Among the several configurations analyzed, a dislocation network pinned at the interface was found to be the most efficient mechanism for strain relief. A detailed description of the dislocation core is given, and the related electronic properties are discussed for the most stable geometry: we found interface states localized in the gap that may be a source of failure of electronic devices

    Cardiovascular autonomic function and MCI in Parkinson's disease

    Get PDF
    Introduction: dysautonomic dysfunction and cognitive impairment represent the most disabling non-motor features of Parkinson's Disease (PD). Recent evidences suggest the association between Orthostatic Hypotension (OH) and PD-Dementia. However, little is known on the interactions between cardiovascular dysautonomia and Mild Cognitive Impairment (MCI). We aimed to evaluate the association between cardiovascular dysautonomia and MCI in patients with PD. Methods: non-demented PD patients belonging to the PACOS cohort underwent a comprehensive instrumental neurovegetative assessment including the study of both parasympathetic and sympathetic function (30:15 ratio, Expiratory-Inspiratory ratio [E-I] and presence of Orthostatic Hypotension [OH]). Diagnosis of MCI was made according to the MDS criteria level II. Results: we enrolled 185 PD patients of whom 102 (55.1%) were men, mean age was 64.6 ± 9.7 years, mean disease duration of 5.6 ± 5.5 years with a mean UPDRS-ME score of 31.7 ± 10.9. MCI was diagnosed in 79 (42.7%) patients. OH was recorded in 52 (28.1%) patients, altered 30:15 ratio was recorded in 39 (24.1%) patients and an altered E-I ratio was found in 24 (19.1%) patients. Presence of MCI was associated with an altered 30:15 ratio (adjOR 2.83; 95%CI 1.25–6.40) but not with an altered E-I ratio, while OH was associated only with the amnestic MCI subgroup (OR 2.43; 95% CI 1.05–5.06). Conclusion: in our study sample, MCI was mainly associated with parasympathetic dysfunction in PD

    Incidence of mild cognitive impairment and dementia in Parkinson's disease: The Parkinson's disease cognitive impairment study

    Get PDF
    Background: Cognitive impairment in Parkinson's disease (PD) includes a spectrum varying from Mild Cognitive Impairment (PD-MCI) to PD Dementia (PDD). The main aim of the present study is to evaluate the incidence of PD-MCI, its rate of progression to dementia, and to identify demographic and clinical characteristics which predict cognitive impairment in PD patients. Methods: PD patients from a large hospital-based cohort who underwent at least two comprehensive neuropsychological evaluations were retrospectively enrolled in the study. PD-MCI and PDD were diagnosed according to the Movement Disorder Society criteria. Incidence rates of PD-MCI and PDD were estimated. Clinical and demographic factors predicting PD-MCI and dementia were evaluated using Cox proportional hazard model. Results: Out of 139 enrolled PD patients, 84 were classified with normal cognition (PD-NC), while 55 (39.6%) fulfilled the diagnosis of PD-MCI at baseline. At follow-up (mean follow-up 23.5 ± 10.3 months) 28 (33.3%) of the 84 PD-NC at baseline developed MCI and 4 (4.8%) converted to PDD. The incidence rate of PD-MCI was 184.0/1000 pyar (95% CI 124.7-262.3). At multivariate analysis a negative association between education and MCI development at follow-up was observed (HR 0.37, 95% CI 0.15-0.89; p = 0.03). The incidence rate of dementia was 24.3/1000 pyar (95% CI 7.7-58.5). Out of 55 PD-MCI patients at baseline, 14 (25.4%) converted to PDD, giving an incidence rate of 123.5/1000 pyar (95% CI 70.3-202.2). A five time increased risk of PDD was found in PD patients with MCI at baseline (RR 5.09, 95% CI 1.60-21.4). Conclusion: Our study supports the relevant role of PD-MCI in predicting PDD and underlines the importance of education in reducing the risk of cognitive impairment

    Use of Eribulin mesylate as second-line therapy in elderly patients with HER/2 negative metastatic breast cancer (MBC): Efficacy, tolerability and Quality of Life

    Get PDF
    OBJECTIVE: Eribulin mesylate (Halaven®) is a non-taxane inhibitor of microtubule indicated as monotherapy in patients with metastatic breast cancer (MBC), which progresses after anthracycline and taxanes therapy. In this retrospective observational study, we want to evaluate the efficacy of Eribulin in elderly women with MBC pretreated with anthracyclines and taxanes. PATIENTS AND METHODS: 40 elderly patients > 70 years of age were enrolled, and the median age was 76 years (range 70-82). Overall survival (OS), Progression Free Survival (PFS), Objective Response Rate (ORR) were primary endpoints, tolerability, carcinoembryonic antigen levels 15.3 (Ca 15.3), before and after treatment, and Quality of Life (QoL) were secondary endpoints. RESULTS: Eribulin treatment was well tolerated, produced a good level of disease control, a manageable toxicity profile and a significant impact on QoL. Median OS was 12.8 months and median PFS was 3.2 months. A significant correlation was observed between reduction of Ca 15.3 and PFS with a value of 0.59 (p = 0.002). CONCLUSIONS: Despite a limited number of patients and a modest manageable toxicity, Eribulin is a chemotherapy treatment that has showed to be an effective and well-tolerated therapeutic option in elderly patients with MBC. Further analysis should focus on the elderly patients in our setting of study
    • …
    corecore