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In this study, a new and simple glassy carbon electrode modified with carbon nanohorns (SWCNH/GCE) was used for the determination of Cr(VI) in aqueous matrices via adsorptive cathodic stripping voltammetry (AdCSV). The modified electrode was characterized via field emission scanning electron microscopy and cyclic voltammetry, which revealed a homogeneous distribution of spherical agglomerates of SWCNH on the electrode surface. The modification increased the electrochemically active area from 0.10 cm 2 ± 0.01 (GCE) to 0.16 cm 2 ± 0.01 (SWCNH/GCE). The optimized analytical conditions were as follows: a supporting electrolyte (0.15 mol L -1 HCl), an accumulation potential of 0.8 V versus Ag/AgCl, and an accumulation time of 240 s. Validation of the analytical methodology was performed, obtaining a linear range between 20 and 100 µg L -1 , a limit of detection of 3.5 µg L -1 , and a limit of quantification of 11.6 µg L -1 with good accuracy and precision. The method was applied to the analysis of spiked tap water samples, and the results were compared using a flame atomic absorption spectrophotometer (FAAS) with no significant statistical differences.

This paper presents an application for a molybdenum disulfide nanomaterial with multiwalled carbon nanotubes (MoS 2 @MWCNT/E) in a modified electrode substrate for the detection of uric acid (UA). The modified electrode generates a substantial three-fold increase in the anodic peak current for UA compared to the unmodified MWCNT electrode (MWCNT/E). The MoS 2 @MWCNT/E surface was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and electrochemical impedance spectroscopy (EIS). The achieved detection limit stood at 0.04 µmol/L, with a relative standard deviation (RSD) of 2.0% (n = 10). The method's accuracy, assessed through relative error and percent recovery, was validated using a urine standard solution spiked with known quantities of UA.

Antimony(III) is a rare electroactive specie present on Earth, whose concentration is not typically determined. The presence of high concentrations of antimony is responsible for a variety of diseases, which makes it desirable to find convenient and reliable methods for its determination. We have developed a convenient glassy carbon modified electrode with electroreduced graphene oxide GC/rGO for the first time determination of Sb(III) in commercial lettuce, celery, and beverages. The surface of the electrode was characterized by scanning electron microscopy (SEM) and cyclic voltammetry, indicating a heterogeneous and rough surface with a real area of 0.28 cm 2 , which is ~2.5 times the area of GC. The optimal chemical and electrochemical parameters used were: sodium acetate buffer (pH = 4.3), an accumulation potential of -1.0 V and an accumulation time of 150 s. The analytical validation was developed evaluating the linear range (10-60 µg L -1 ), limit of detection (2.5 µg L -1 ), accuracy, repetibility and reproducibility with satisfactory results (relative standard deviation (RSD) values lower than 10%). All the analyzes performed in real samples by stripping voltammetry were compared with GF-AAS, showing statistically similar values, demonstrating that GC/rGO could be effectively applied in the analysis of food samples., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Calcium carbonate nanoparticles (CaCO 3 NPs) derived from CO 2 are promising materials for different industrial applications. It is imperative to understand their toxicological profile in biological systems as the human and environmental exposures to CaCO 3 NPs increases with growing production. Here, we analyse the cytotoxicity of CaCO 3 NPs synthesized from a CaO slurry on two cell lines, and in vivo on zebrafish (Danio Rerio). Our results demonstrate the CaCO 3 NPs in vitro safety as they do not cause cell death or genotoxicity. Moreover, zebrafish treated with CaCO 3 NPs develop without any abnormalities, confirming the safety and biocompatibility of this nanomaterial., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

Background: Chile is a low-endemic HBV country, but countries with the highest migratory flow to Chile have an intermediate-high endemicity. In order to avoid vertical transmission of HBV, immunoprophylaxis (IP) in the newborn (NB) is a key factor., Aim: To identify HBsAg prevalence in pregnant immigrants and Chilean pregnant women with risk behaviors (RB) and to asses IP use in the NB., Material and Methods: Prospective HBsAg screening cohort of immigrant and Chilean pregnant women with RB, between July 1, 2017 and June 30, 2018 in CABL. IP of all NB of reactive HBsAg mothers was assessed., Results: 1,415 HBsAg samples, 1,265 immigrants and 150 Chileans with RB. 37 reactive HBsAg. Two false positive. HBsAg prevalence in immigrant pregnant women was 2.7% and 0.66% in Chileans with RB (p < 0.05). 91.1% came from Haiti, with a prevalence of 3.5% in our region. All NB (36) received IP with a median of administration of 3:02 h., Conclusions: The prevalence in immigrant pregnant women was higher than that reported in the general population and in Chilean women with RB. We proposed the need for universal screening in pregnancy, especially in pregnant women from countries with intermediate-high endemicity.

Background: Plasmapheresis can be useful in myasthenia gravis, Guillain Barré syndrome and chronic demyelinating inflammatory polyradiculoneuritis., Aim: To report our experience with plasmapheresis in patients with neurological diseases., Material and Methods: Retrospective review of plasmapheresis procedures done between 1995 and 2001, in a public hospital. Indications criteria, clinical results and technical yield were analyzed., Results: One hundred fifty nine procedures were reviewed. One hundred forty (88%) were indicated for neurological diseases (44% for Guillain Barré syndrome and 29% for myasthenia gravis). Clinical improvement or eventual complications were avoided in 70% of patients with Guillain Barré syndrome and 100% of patients with myasthenia gravis. Hypotension in 10% and paresthesias in 7% were observed. All complications were successfully controlled with crystalloid or fresh plasma infusions or citrate management. In 11 cases, the procedure was interrupted due to obstruction of the venous access, that was peripheral in eight of these. The most common difficulties of the procedure were delay in performing it in 50% of patients and insufficient exchange volumes in 30%., Conclusions: Plasmapheresis was safe and useful in patients with myasthenia gravis and Guillain Barré syndrome. The drawbacks of the procedure are its costs and requirement of special equipment.

Background: Cellular immune mechanisms of the resistance to infection by T cruzi as well as the pathogenesis of Chagas disease are still controversial., Aim: To quantify and analyse the peripheral blood immune cells from chagasic and non chagasic patients by flow cytometry., Patients and Methods: Peripheral blood samples were taken from 21 individuals seropositive for Chagas disease, under no specific treatment. Control samples from 21 healthy blood donors were also obtained. To quantify immune cells populations by flow cytometry, antibodies against CD3, CD4, CD8, CD16/56, CD45/14, CD19 and HLA-DR markers were used., Results: The percentage of CD8+ cells was low and the CD4+/CD8+ ratio was high in chagasic patients, compared to their non infected counterparts. No statistically significant differences in the number of CD4+, NK, B, CD4+HLADR+ and CD8+HLADR+ cells, were observed within the two groups., Conclusions: These results show that Chilean chronic chagasic patients have lower percentage of CD8+ cells and higher CD4+/CD8+ ratio than non infected individuals.