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The employment of granular ferric iron-(oxy)hydroxides, a well-known economic and effective method, lowers arsenic concentrations in different water types. However, for direct application in polluted groundwaters, there is a need to develop new injectable adsorbents for aquifers that could also neutralize acidic media. In this context, a granular ferric hydroxide-calcite (GFH-C) adsorbent was size-reduced to 0.4–50 µm by sonication with the aim of improving (i) the adsorption of As(III) and As(V) at different pHs and (ii) the pH control through the dissolution of calcite. Batch experiments were conducted to determine As(III) and As(V) adsorption isotherms and kinetics, as well as calcite dissolution kinetics, using GFH-C of two sizes (granular and sonicated). Results showed that the arsenic binding capacity of sonicated adsorbents did not improve significantly. On the contrary, the As(III) and As(V) adsorption kinetics improved with the sonication, as in the case of calcite dissolution kinetics. The dissolution of calcite from the adsorbent made the water pH increase to around 9.2–9.4. The sonicated adsorbent offers an advantage in depolluting As-containing groundwater due to its smaller size, which is linked with faster arsenic adsorption and effective acidic water neutralization. [ABSTRACT FROM AUTHOR]

Carbon-nanofiber-based screen-printed electrodes modified with silver nanoparticles (Ag-NP-SPCNFEs) were tested in a pioneering manner for the direct determination of As(V) at low μg L -1 levels by means of differential pulse anodic stripping voltammetry. Screen-printed electrodes were modified with two different types of Ag-NPs, nanoseeds (NS), and nanoprisms (NPr) and characterized both microscopically and electrochemically. Furthermore, after optimizing the direct voltammetric determination of As(V), the analytical performance of considered sensors was compared for the direct determination of As(V). These results suggest that Ag-NS offer a better analytical response compared to Ag-NPr, with a detection and quantification limit of 0.6 and 1.9 µg L -1 , respectively. The proposed methodology was validated using a spiked tap water sample with a very high reproducibility and good agreement with inductively coupled plasma - mass spectrometry (ICP-MS) measurements.

Background and Objective: To assess whether there are differences in the rate of restenosis between bare metal stents (BMS) and drug eluting stents (DES) implanted for the treatment of cardiac allograft vasculopathy (CAV)., Patients and Methods: This retrospective study describes the baseline characteristics, clinical and angiographic evolution of a sample of heart transplant patients treated with coronary stent implantation due to CAV., Results: We analyzed the follow-up of 40 stents (17 BMS and 23 DES). Mean follow-up was 28 ± 18 months (range 12 to 84). The DES group had a lower rate of active smoking, a higher percentage of residual stenosis and an increased use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Control angiography was performed in 33 stents (82%). In the BMS group (n=15), 8 restenosis were identified (53%) whereas 2 (11%) were seen in the DES group (n=18) (P=.02)., Conclusion: In this series a lower rate of restenosis was observed in the DES group, attributable to the effect of the drug released locally by the stent., (Copyright © 2011 Elsevier España, S.L. All rights reserved.)