Alpha-Lipoic Acid and Its Enantiomers Prevent Methemoglobin Formation and DNA Damage Induced by Dapsone Hydroxylamine: Molecular Mechanism and Antioxidant Action

Dapsone (DDS) therapy can frequently lead to hematological side effects, such as methemoglobinemia and DNA damage. In this study, we aim to evaluate the protective effect of racemic alpha lipoic acid (ALA) and its enantiomers on methemoglobin induction. The pre- and post-treatment of erythrocytes with ALA, ALA isomers, or MB (methylene blue), and treatment with DDS-NOH (apsone hydroxylamine) was performed to assess the protective and inhibiting effect on methemoglobin (MetHb) formation. Methemoglobin percentage and DNA damage caused by dapsone and its metabolites were also determined by the comet assay. We also evaluated oxidative parameters such as SOD, GSH, TEAC (Trolox equivalent antioxidant capacity) and MDA (malondialdehyde). In pretreatment, ALA showed the best protector effect in 2.5 µg/mL of DDS-NOH. ALA (1000 µM) was able to inhibit the induced MetHb formation even at the highest concentrations of DDS-NOH. All ALA tested concentrations (100 and 1000 µM) were able to inhibit ROS and CAT activity, and induced increases in GSH production. ALA also showed an effect on DNA damage induced by DDS-NOH (2.5 µg/mL). Both isomers were able to inhibit MetHb formation and the S-ALA was able to elevate GSH levels by stimulating the production of this antioxidant. In post-treatment with the R-ALA, this enantiomer inhibited MetHb formation and increased GSH levels. The pretreatment with R-ALA or S-ALA prevented the increase in SOD and decrease in TEAC, while R-ALA decreased the levels of MDA; and this pretreatment with R-ALA or S-ALA showed the effect of ALA enantiomers on DNA damage. These data show that ALA can be used in future therapies in patients who use dapsone chronically, including leprosy patients.     

Efficient Near-Infrared Light-Emitting Diodes Based on CdHgSe Nanoplatelets

Cadmium mercury selenide (CdHgSe) nanocrystals exhibit a unique combination of low-energy optical absorption and emission, which can be tuned from the visible to the infrared range through both quantum confinement and adjustment of their composition. Owing to this advantage, such nanocrystals have been studied as a promising narrow-band infrared light emitter. However, the electroluminescence of CdHgSe-based nanocrystals has remained largely unexplored, despite their potential for emitting light in the telecom wavelength range. Further benefits to their optical properties are expected from their shape control, in particular the formation of 2D nanocrystals, as well as from a proper design of their heterostructures. In this work, a colloidal synthesis of CdHgSe/ZnCdS core/shell nanoplatelets (NPLs) starting from CdSe template NPLs employing a cation exchange strategy is developed. The heterostructures synthesized exhibit photoluminescence that can be tuned from ≈1300 to 1500 nm. These near-infrared-active NPLs are employed in light-emitting diodes, demonstrating low turn-on voltage and high external quantum efficiency.     

Synthesis and characterization of nanoparticles and thin films of PbS by a high-performance procedure using CBD

Journal of Materials Science: Materials in Electronics - The present work is devoted to find a simple, inexpensive, and efficient synthesis for PbS. Nanoparticles and nanostructured thin films of...     

Impact of environmental strategies and practices on the socioeconomic development of the Brazilian sugar-energy sector

Clean Technologies and Environmental Policy - Different environmental strategies have been devised and implemented as instruments to change companies’ socio-environmental behavior worldwide....     

Fundamental understanding of high-capacity lithium-excess cathodes with disordered rock salt structure

As a new class of lithium rich cathodes,disordered rock-salt cathodes have been of primary interest,because of their ability to deliver a promisingly high capacity up to 300 mA h/g.Nevertheless,some fundamental issues are yet to be fully understood and a comprehensive mastering of their solid-state chemistry,kinetics and thermal stability is required.Here,we select a high capacity cation-disordered positive electrode-Li1.2Ni0.4Nb0.4O2 as a model compound to study intrinsic reaction mechanism,including charge compensation mechanism,kinetics,thermal stability,and structural evolution.By combining soft and hard X-ray absorption spectroscopy (XAS),X-ray photoelectron spectroscopy (XPS) with operando and exsitu differential scanning calorimetry (DSC),galvanostatic intermittent titration technique (GITr),cyclic voltammetry (CV),and X-ray diffraction (XRD),we present holistic information on disordered rock-salt cathode.This work provides beneficial insights into designing and tailoring new positive electrodes with disordered rock-salt structure.     

How are software technologies being evaluated with autistic users? A systematic mapping

Universal Access in the Information Society - Evaluating software technologies with users is a way to ensure the software purpose is accomplished before the system becomes available to the final...     

Sulfated and Oxygenated Imidazoline Derivatives: Synthesis,Antioxidant Activity and Light-Mediated Antibacterial Activity

Imidazoline derivatives with different exocyclic substituents were simply prepared from common starting materials. The procedures were carried out in an eco-friendly manner. The antioxidant activity of these derivatives was explored by different experimental assays, such as ABTS^.+ and DPPH^. scavenging assay, as well as reducing power assay. The structural differences are discussed in terms of the results. Sulfur analogs showed higher antioxidant activity than their oxygenated counterparts. The same tendency was observed in microbiological studies, in which the same imidazoline compounds were assayed for light-mediated activity against of Staphylococcus aureus and Escherichia coli strains. A light-enhanced activity was observed for almost all the sulfated imidazolines after exposure to UV-A (400-320 nm) light.     

Dissolution,bioactivity behavior,and cytotoxicity of rare earth-containing bioactive glasses (RE = Gd,Yb)

Rare earth-containing bioactive glasses (RE-BGs) have been poorly explored in the biomaterials field, although RE has optical, nuclear, and magnetic properties that could be used in different biomedical applications. In order to verify whether these glasses can be promising as biomaterials, we studied the dissolution, bioactivity, and cytotoxicity of RE-BGs based on the SiO₂–Na₂O–CaO–P₂O₅–RE₂O₃ (RE = Gd, Yb) system. The glasses were obtained by melting-quenching and their particle size was determined by laser diffraction. Their dissolution behavior was studied in Tris-HCl, while bioactivity was performed in simulated body fluid solution under physiological conditions during several periods. The cytotoxicity test was performed using glass-derived conditioned medium and mesenchymal stem cell derived from deciduous teeth. The dissolution results showed that the glasses dissolved under two different kinetics, which are lower for rare earth-containing glasses, due to the more covalent character of Si–O–RE bonds. The bioactivity results evidenced that all glasses showed bioactivity after 24 hours. However, gadolinium and ytterbium promoted a more calcium phosphate deposition, which contrasts with the slower dissolution kinetics of rare earth-containing glasses. All the glasses were considered biocompatible, showing cell viability higher than 80%. The overall results showed that RE-BGs are promising materials for applications that require bioactivity and/or biocompatibility.