Electrochemical and spectroscopic characterisations of cation exchange membrane equilibrated in acid and salt solutions: application as separator in microbial fuel cell

<div><p>The polymer cation exchange membrane (Nafion117) was equilibrated garden soil leachate. It was then characterised using the stationary voltamperometry method and the mass transfer electrochemical Hittorf-based method. The results obtained with these two techniques were compared to those obtained with the membrane conditioned only with conventional acid and/or salt electrolytes solutions. These two conditions highlighted the good proton conduction of the membrane, against metal ions. This finding was supported and complemented by impedance spectroscopic studies at both transient and stationary regimes. The parameters studied were electrical impedance and specific conductivity. It was found that at higher frequencies, the conductivity of the membrane conditioned with protons was five times higher than that stored in distilled water. As an application, the membrane was tested successfully in a garden soil microbial fuel cell under study, thereby evidencing its good proton conduction. Nafion exhibits, therefore, a high protonic conductivity when hydrated, because protons can be transported via Grotthus and hopping mechanisms via its functional sites.</p></div

Circulating microRNAs and Outcome in Patients with Acute Heart Failure

BACKGROUND: The biomarker value of circulating microRNAs (miRNAs) has been extensively addressed in patients with acute coronary syndrome. However, prognostic performances of miRNAs in patients with acute heart failure (AHF) has received less attention. METHODS: A test cohort of 294 patients with acute dyspnea (236 AHF and 58 non-AHF) and 44 patients with stable chronic heart failure (CHF), and an independent validation cohort of 711 AHF patients, were used. Admission levels of miR-1/-21/-23/-126/-423-5p were assessed in plasma samples. RESULTS: In the test cohort, admission levels of miR-1 were lower in AHF and stable CHF patients compared to non-AHF patients (p = 0.0016). Levels of miR-126 and miR-423-5p were lower in AHF and in non-AHF patients compared to stable CHF patients (both p<0.001). Interestingly, admission levels of miR-423-5p were lower in patients who were re-admitted to the hospital in the year following the index hospitalization compared to patients who were not (p = 0.0001). Adjusted odds ratio [95% confidence interval] for one-year readmission was 0.70 [0.53-0.93] for miR-423-5p (p = 0.01). In the validation cohort, admission levels of miR-423-5p predicted 1-year mortality with an adjusted odds ratio [95% confidence interval] of 0.54 [0.36-0.82], p = 0.004. Patients within the lowest quartile of miR-423-5p were at high risk of long-term mortality (p = 0.02). CONCLUSIONS: In AHF patients, low circulating levels of miR-423-5p at presentation are associated with a poor long-term outcome. This study supports the value of miR-423-5p as a prognostic biomarker of AHF