Double-template fabrication of three-dimensional porous nickel electrodes for hydrogen evolution reaction

[EN] Three-dimensional (3D) porous nickel structures were fabricated via a double-template electrochemical deposition process. The construction of the foam structures was achieved by means of a hydrogen bubble dynamic template, prepared from Cu electrodeposition at high current densities. Subsequently, a Ni layer was electrodeposited on the Cu 3D template. During the nickel coating, the typical finger-like microstructure of the Cu foam becomes denser and changes to a cauliflower microstructure. The hydrogen evolution reaction (HER) on these macroporous Ni electrodes was evaluated in 30 wt.% KOH solution by means of polarization curves and electrochemical impedance spectroscopy (EIS). Results demonstrate greater apparent activity of the developed electrodes towards HER in comparison with commercial smooth Ni electrode. The 3D porous Ni electrocatalyst obtained from Cu templates synthesized at the lowest current density and the highest electrodeposition time yielded the best electrochemical activity for HER. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Isaac Herraiz-Cardona is grateful to the Ministerio de Educacion (Spain) for a postgraduate grant (Ref. AP2007-03737). This work was supported by Generalitat Valenciana (PROMETEO/2010/023) and Universidad Politecnica de Valencia (PAID-06-10-2227).Herraiz-Cardona, I.; Ortega Navarro, EM.; Vázquez-Gómez, L.; Pérez-Herranz, V. (2012). Double-template fabrication of three-dimensional porous nickel electrodes for hydrogen evolution reaction. International Journal of Hydrogen Energy. 37(3):2147-2156. https://doi.org/10.1016/j.ijhydene.2011.09.155S2147215637

Electrochemical characterization of a NiCo/Zn cathode for hydrogen generation

[EN] Hydrogen is considered to be the most promising candidate as a future energy carrier. One of the most used technologies for the electrolytic hydrogen production is alkaline water electrolysis. However, due to the high energy requirements, the cost of hydrogen produced in such a way is high. In continuous search to improve this process using advanced electrocatalytic materials for the hydrogen evolution reaction (HER), high area NiCo/Zn electrodes were prepared on AISI 304 stainless steel substrates by electrodeposition. After preparing, the alloys were leached of to remove part of the zinc and generate a porous layer (type Raney electrodes). The presence of a thin Ni layer between the substrate and the Raney coating favour the adherence of the latter. The porous NiCo/Zn electrode was characterized by SEM, EDX, confocal laser microscopy, and electrochemical impedance spectroscopy. HER on this electrode was evaluated in 30 wt.% KOH solution by means of polarization curves, hydrogen discharge curves, and galvanostatic tests. Results show that the developed electrode presents a most efficient behaviour for HER when comparing with the smooth Ni cathode. The high electrode activity was mainly attributed to the high surface area of the developed electrode. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Isaac Herraiz-Cardona is grateful to the Ministerio de Ciencia e Innovacion (Spain) for a postgraduate grant (Ref. AP2007-03737). This work was supported by Generalitat Valenciana (Project PROMETEO/2010/023).Herraiz-Cardona, I.; Ortega Navarro, EM.; Vázquez-Gómez, L.; Pérez-Herranz, V. (2011). Electrochemical characterization of a NiCo/Zn cathode for hydrogen generation. International Journal of Hydrogen Energy. 36(18):11578-11587. https://doi.org/10.1016/j.ijhydene.2011.06.067S1157811587361

Synergic effect of metabolic syndrome and lipodystrophy on oxidative stress and inflammation process in treated HIV-patients.

The aim of this study was to assess the effect of lipodystrophy (LD) associated to metabolic syndrome (MS) on oxidative stress and inflammation in a cohort of 243 HIV-infected patients with MS, all of them under three different antiretroviral regimens. We collected immunovirological, biochemical and metabolic data, as well as anthropometric measurements. In addition, cardiovascular risk was also assessed by means of Atherogenic Index of Plasma (API) and Framingham Risk Score. The MS-LD patient set was characterized by a lower initial lymphocyte CD4 count and CD4/CD8 ratio and a higher initial viral load than the group without LD. We also found worse lipidic and glycaemic profiles (with lower HDL-cholesterol and higher triglyceride and glucose levels) in the MS-LD group. BMI, systolic blood pressure and Framingham score were significantly increased compared to MS-Non LD. In addition, patients with MS and LD had significantly higher levels of carbonylated proteins, lipid peroxidation, IL-6 and IL-8, as well as a significant decrease in the levels of leptin, adiponectin and antioxidant activities of catalase, super oxide dismutase and glutathione associated enzymes. In MS-LD HIV-1 patients, a significant negative correlation was found between Framingham Risk Score and the antioxidant biomarkers, however a positive association was found between API and protein-C reactive and carbonylated proteins. Segregating by ART, the above-mentioned conditions were worse within the MS-LD group whose treatment contained protease inhibitors, such as lopinavir. In conclusion, HIV-1 infected patients treated for at least six months, especially with regimens including PIs, showed a worsening of inflammatory process and oxidative stress.This work was supported by the Spanish Ministry of Science and Innovation [SAF 2010-17213]; the Regional Ministry of Health from the Andalusian Government [SAS 111226]; “Miguel Servet Type II” grant [CPI13/00003 to M.I.Q.O. and CPII18/00030 to L.G.S.] from ISCIII, co-funded by the European Regional Development Fund (ERDF); “Nicolas Monardes” research program from the Regional Ministry of Health from the Andalusian Government [C-0030-2018 to M.I.Q.O. and C-0028-2018 to L.G.S.

The HER in alkaline media on Pt-modified three-dimensional Ni cathodes

[EN] Electrodeposited porous Ni layers and commercial Ni foams were submitted to spontaneous deposition of Pt, achieved by immersing the Ni substrates in H2PtCl6 solutions, at open circuit, to produce Pt-modified 3D Ni electrodes. When using Ni foams, the immersion was prolonged until the whole amount of H2PtCl6 in the solution had reacted. Such an approach, which granted an easy control of the Pt loading, could not be used for Ni trodeposits, since they underwent significant corrosion. The true Pt surface area was determined by measuring, for each electrode, the hydrogen desorption charge according to methods described in the literature. The ratios between Pt surface area and Pt loading were higher for Ni foam electrodes than for porous Ni electrodeposits. Both kinds of Pt-modified Ni electrodes were used as cathodes for hydrogen evolution in 1 M KOH. Cathodes with Pt loading below 0.5 mg cm(-2) (referred to geometric surface area) evolved hydrogen at -100 mA cm(-2) with a -75 mV overpotential. The better activity of foam electrodes as compared to electrodeposits, especially at low Pt loading, was mainly due to their higher Pt surface area per unit Pt mass. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.The authors from IENI-CNR acknowledge the financial support of the Italian Ministry for Economic Development (MSE) - MSE-CNR Agreement on National Electrical System. I. Herraiz-Cardona is grateful to the Ministerio de Educacion of Spain for a post-graduate grant (Ref. AP2007-03737). The authors are indebted to Dr. Arianna Gambirasi, ICIS CNR, Padova, Italy for recording SEM images and to FILA INDUSTRIA CHIMICA SPA, San Martino di Lupari, Padova, Italy, owner of the Fei-ESem FEI Quanta 200 FEG instrument, for allowing its use for the research work described in this article.Fiameni, S.; Herraiz Cardona, I.; Musiani, M.; Pérez-Herranz, V.; Vázquez-Gómez, L.; Verlato, E. (2012). The HER in alkaline media on Pt-modified three-dimensional Ni cathodes. International Journal of Hydrogen Energy. 37(14):10507-10516. https://doi.org/10.1016/j.ijhydene.2012.04.100S1050710516371

Un problema ético en la especialidad de Cirugía. Experiencia personal

A case is presented where a patient referred to the General Surgery Service from the Luanda Main Military Hospital, Angola, has suffered a great loss of abdominal wall, fibrinopurulent peritonitis and severe sepsis due to firearm abdominal wound, and had improved its general condition in spite of divergent criteria about its state.Se presenta un paciente atendido en el Servicio de Cirugía General del Hospital Militar Principal de Luanda, Angola, con gran pérdida de la pared abdominal, peritonitis fibrino-purulenta y sepsis grave debido a una herida abdominal (ocasionada por un arma de fuego) que evoluciona favorablemente, a pesar de criterios diferentes ante su grave estado

Fine Mapping of the Interaction between C4b-Binding Protein and Outer Membrane Proteins LigA and LigB of Pathogenic Leptospira interrogans.

The complement system consists of more than 40 proteins that participate in the inflammatory response and in pathogen killing. Complement inhibitors are necessary to avoid the excessive consumption and activation of this system on host cells. Leptospirosis is a worldwide zoonosis caused by spirochetes from the genus Leptospira. Pathogenic leptospires are able to escape from complement activation by binding to host complement inhibitors Factor H [FH] and C4b-binding protein (C4BP) while non-pathogenic leptospires are rapidly killed in the presence of fresh serum. In this study, we demonstrate that complement control protein domains (CCP) 7 and 8 of C4BP α-chain interact with the outer membrane proteins LcpA, LigA and LigB from the pathogenic leptospire L. interrogans. The interaction between C4BP and LcpA, LigA and LigB is sensitive to ionic strength and inhibited by heparin. We fine mapped the LigA and LigB domains involved in its binding to C4BP and heparin and found that both interactions are mediated through the bacterial immunoglobulin-like (Big) domains 7 and 8 (LigA7-8 and LigB7-8) of both LigA and LigB and also through LigB9-10. Therefore, C4BP and heparin may share the same binding sites on Lig proteins

Fine Mapping of the Interaction between C4b-Binding Protein and Outer Membrane Proteins LigA and LigB of Pathogenic Leptospira interrogans.

The complement system consists of more than 40 proteins that participate in the inflammatory response and in pathogen killing. Complement inhibitors are necessary to avoid the excessive consumption and activation of this system on host cells. Leptospirosis is a worldwide zoonosis caused by spirochetes from the genus Leptospira. Pathogenic leptospires are able to escape from complement activation by binding to host complement inhibitors Factor H [FH] and C4b-binding protein (C4BP) while non-pathogenic leptospires are rapidly killed in the presence of fresh serum. In this study, we demonstrate that complement control protein domains (CCP) 7 and 8 of C4BP α-chain interact with the outer membrane proteins LcpA, LigA and LigB from the pathogenic leptospire L. interrogans. The interaction between C4BP and LcpA, LigA and LigB is sensitive to ionic strength and inhibited by heparin. We fine mapped the LigA and LigB domains involved in its binding to C4BP and heparin and found that both interactions are mediated through the bacterial immunoglobulin-like (Big) domains 7 and 8 (LigA7-8 and LigB7-8) of both LigA and LigB and also through LigB9-10. Therefore, C4BP and heparin may share the same binding sites on Lig proteins

Chemical Chaperones Curcumin and 4-Phenylbutyric Acid Improve Secretion of Mutant Factor H R127H by Fibroblasts from a Factor H-Deficient Patient

Factor H (FH) is one of the most important regulatory proteins of the alternative pathway of the complement system. Patients with FH deficiency have a higher risk for development of infections and kidney diseases because of the uncontrolled activation and subsequent depletion of the central regulatory component C3 of the complement system. In this study, we investigated the consequences of the Arg(127)His mutation in FH (FHR127H) previously described in an FH-deficient patient, on the secretion of this protein by skin fibroblasts in vitro. We observed that, although the patient cells stimulated with IFN-gamma were able to synthesize FHR127H, the mutant protein was largely retained within the endoplasmic reticulum (ER), whereas normal human fibroblasts stimulated with IFN-gamma secrete FH without retention in the ER. Moreover, the retention of FHR127H provoked enlargement of ER cisterns after treatment with IFN-gamma. A similar ER retention was observed in Cos-7 cells expressing the mutant FHR127H protein. Despite this deficiency in secretion, we show that the FHR127H mutant is capable of functioning as a cofactor in the Factor I-mediated cleavage of C3. We then evaluated whether a treatment could increase the secretion of FH, and observed that the patient's fibroblasts treated with the chemical chaperones 4-phenylbutiric acid or curcumin increased the secretion rate of FH. We propose that these chemical chaperones could be used as alternative therapeutic agents to increase FH plasma levels in FH-deficient patients caused by secretion delay of this regulatory protein. The Journal of Immunology, 2012, 189: 3242-3248.Fundacao de Amparo a Pesquisa do Estado de Sao PauloFundacao de Amparo a Pesquisa do Estado de Sao PauloConselho Nacional de Pesquisa e Desenvolvimento Cientifico, BrazilConselho Nacional de Pesquisa e Desenvolvimento Cientifico, Brazi

Therapeutic strategies based on modified U1 snRNAs and chaperones for Sanfilippo C splicing mutations

Mutations affecting RNA splicing represent more than 20% of the mutant alleles in Sanfilippo syndrome type C, a rare lysosomal storage disorder that causes severe neurodegeneration. Many of these mutations are localized in the conserved donor or acceptor splice sites, while few are found in the nearby nucleotides. In this study we tested several therapeutic approaches specifically designed for different splicing mutations depending on how the mutations affect mRNA processing. For three mutations that affect the donor site (c.234 + 1G > A, c.633 + 1G > A and c.1542 + 4dupA), different modified U1 snRNAs recognizing the mutated donor sites, have been developed in an attempt to rescue the normal splicing process. For another mutation that affects an acceptor splice site (c.372-2A > G) and gives rise to a protein lacking four amino acids, a competitive inhibitor of the HGSNAT protein, glucosamine, was tested as a pharmacological chaperone to correct the aberrant folding and to restore the normal trafficking of the protein to the lysosome. Partial correction of c.234 + 1G > A mutation was achieved with a modified U1 snRNA that completely matches the splice donor site suggesting that these molecules may have a therapeutic potential for some splicing mutations. Furthermore, the importance of the splice site sequence context is highlighted as a key factor in the success of this type of therapy. Additionally, glucosamine treatment resulted in an increase in the enzymatic activity, indicating a partial recovery of the correct folding. We have assayed two therapeutic strategies for different splicing mutations with promising results for the future applications