16 research outputs found

    Investigation of Autonomic Function and Orocecal Transit Time in-Patients With Nonalcoholic Cirrhosis and the Potential Influence of These Factors on Disease Outcome

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    Background: The presence of autonomic dysfunction in nonalcoholic cirrhosis and its influence on intestinal transit and disease outcome still need clarification. Goals: To investigate the function of the autonomic nervous system in patients with nonalcoholic cirrhosis and the possible associations among autonomic dysfunction, severity of liver disease, disturbed intestinal transit, and the development of complications during follow-up. Study: Measurements of heart rate variability obtained by analysis of 24-hour ambulatory electrocardiographic recordings to assess autonomic function and lactulose breath hydrogen test to determine orocecal transit time were performed in 32 patients with nonalcoholic cirrhosis divided into Child A and B. Results: Child B patients showed significantly lower values (P < 0.05) of those parameters reflecting parasympathetic (high frequency, log-transformed high frequency, pNN50) and sympathetic function (low frequency, log-transformed low frequency) in comparison with controls and Child A patients. Orocecal transit time values were significantly (P = 0.02) higher in Child B patients than in controls, but no relationship was found between delayed orocecal transit time and autonomic dysfunction. During follow-up, 42% of Child B patients developed encephalopathy. This complication was significantly associated with autonomic dysfunction. In addition, in the 4 patients who died the parameters reflecting parasympathetic function were significantly reduced in comparison with those of survivors. Conclusions: Autonomic dysfunction and delayed intestinal transit are related to the severity of disease in nonalcoholic cirrhosis. Autonomic dysfunction seems to predispose cirrhotic patients to the development of encephalopathy and tray be associated with a poor prognosis of these patients.43988488

    MnO&lt;sub&gt;2&lt;/sub&gt;-Ir Nanowires:Combining Ultrasmall Nanoparticle Sizes, O-Vacancies, and Low Noble-Metal Loading with Improved Activities towards the Oxygen Reduction Reaction

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    Although clean energy generation utilizing the Oxygen Reduction Reaction (ORR) can be considered a promising strategy, this approach remains challenging by the dependence on high loadings of noble metals, mainly Platinum (Pt). Therefore, efforts have been directed to develop new and efficient electrocatalysts that could decrease the Pt content (e.g., by nanotechnology tools or alloying) or replace them completely in these systems. The present investigation shows that high catalytic activity can be reached towards the ORR by employing 1.8 ± 0.7 nm Ir nanoparticles (NPs) deposited onto MnO2 nanowires surface under low Ir loadings (1.2 wt.%). Interestingly, we observed that the MnO2-Ir nanohybrid presented high catalytic activity for the ORR close to commercial Pt/C (20.0 wt.% of Pt), indicating that it could obtain efficient performance using a simple synthetic procedure. The MnO2-Ir electrocatalyst also showed improved stability relative to commercial Pt/C, in which only a slight activity loss was observed after 50 reaction cycles. Considering our findings, the superior performance delivered by the MnO2-Ir nanohybrid may be related to (i) the significant concentration of reduced Mn3+ species, leading to increased concentration of oxygen vacancies at its surface; (ii) the presence of strong metal-support interactions (SMSI), in which the electronic effect between MnOx and Ir may enhance the ORR process; and (iii) the unique structure comprised by Ir ultrasmall sizes at the nanowire surface that enable the exposure of high energy surface/facets, high surface-to-volume ratios, and their uniform dispersion
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