25 research outputs found

    Marie Anne Paulze Lavoisier: unha descoñecida científica

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    [RESUMO] A contribución das mulleres á creación científica ao longo da historia da Humanidade non parece importante se consideramos o pouco que aparecen nos libros de texto; deste xeito, o alumnado non advertirá a existencia de mulleres que fixeron ou elaboraron leis ou teorías nas ciencias. Personaxes como: Hipatia de Alejandría, Hildegarda de Birgen, Caroline Herschel, María Cunitz, Marie Orr Evershed, Augusta Ada Byron, María Montagu, María Agnesi, Sophía Germain, Sonya Kovalevski, María Goeppter Mayer, Rosalin Franklin, Lise Meitner,..., son descoñecidas do gran público. Incluso aquelas que resultan ser coñecidas, como Irene ou Marie Curie, tampouco foron dabondo valoradas. Para recuperar estas mulleres científicas do silencio e do esquecemento e facelas visibles debemos sacar á luz as súas achegas. Este é o caso da protagonista da nosa comunicación. Marie-Anne Pierrette Paulze, que nos libros aparece como a esposa de Lavoisier, pero non como unha persoa con coñecementos científicos profundos como esperamos amosar. Presentamos as súas no mundo da química, que practicaba xunto ao seu home, e a todos cantos científicos formaban o chamado grupo do Arsenal

    Comparative study of the antitumoral activity of phosphine- thiosemicarbazone gold(I) complexes obtained by different methodologies

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    A series of phosphino-thiosemicarbazone gold(I) dinuclear complexes obtained by two different synthetic pro- cedures have been prepared. All the compounds have been spectroscopically characterized including single crystal X ray diffraction analysis in some of cases. [Au2(HL1)Cl2] (1), [Au2(HL2)2]Cl2 (2) and [Au2(HL3)2]Cl2 (3) have been prepared by chemical synthesis using a gold(III) salt as precursor; while [Au2(L1)2] (4), [Au2(L2)2] ∙2CH3CN (5) and [Au2(L3)2] (6) have been isolated from an electrochemical synthesis (HLn=2-[2-(diphenyl- phosphanyl)-benzylidene]-N-R-thiosemicarbazone; HL1: R=methyl, HL2: R=methoxyphenyl, HL3: R=nitrophenyl). The in vitro cytotoxic activity of these gold(I) complexes was tested against some human tumor cell lines: HeLa 229 (cervical epithelial carcinoma), MCF-7 (ovarian adenocarcinoma), NCI-H460 (non- small-cell lung cancer) and MRC5 (normal human lung fibroblast), and the IC50 values compared with those of cisplatin. The neutral methyl-substituted complexes 1 and 4 and methoxyphenyl 5 displayed significant cyto- toxic activities in all investigated cancer cell lines, being 1 and 4 the most effective. The ability of complexes 1 and 4 to induce cell death by apoptosis in Hela 229 was also investigated by fluorescence microscopy using the apoptotic DNA fragmentation as marker. These results indicated that the inhibition of cell proliferation is mainly due to an apoptotic process. In order to obtain more information about the mechanism of action of these me- tallocompounds, the interactions of complexes 1 and 4 with the thioredoxin reductase (TrxR) enzyme were analyzed. Both complexes exhibited a strong inhibition of the thioredoxin reductase activity.We thank Xunta de Galicia (ED431C 2018/13 and ED431D 2017/01), MINECO (CTQ2017-90802-REDT) and Ministerio de Ciencia, Innovación y Universidades (RED2018-102471-T) for financial support. L. M. G. B. thanks Xunta de Galicia for the predoctoral contract (type A).S

    Electrochemical Conversion of the Lignin Model Veratryl Alcohol to Veratryl Aldehyde Using Manganese(III)-Schiff Base Homogeneous Catalysts

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    Lignin and other colored structures need to be bleached after the Kraft process in the pulp industry. Development of environmentally-safe bleaching catalysts or electrocatalysts constitutes an attractive strategy for selective removal of lignin. Seven manganese(III)-complexes with Schiff base ligands 1–7 were synthetized and characterized by different analytical and spectroscopic techniques. The tetragonally elongated octahedral geometry for the manganese coordination sphere and the global µ-aquo dimeric structure were revealed by X-ray diffraction (XRD) studies for 1, Mn2L12(H2O)2(N(CN)2)2 (N(CN)2 = dicyanamide). Complexes 1–4 behave as more efficient peroxidase mimics as compared to 5–7. Electrochemical oxidation of the lignin model veratrylalcohol (VA) to veratrylaldehyde (VAH) is efficiently catalyzed by a type of dimanganese(III) complexes in a chlorine-free medium. The electrocatalytic reaction proceeds through the oxidation of chloride into hypochlorite at alkaline pH along with the formation of hydrogen from water as a subproductThis research was funded by Xunta de Galicia (GRC GI-1584-ED431C2018/13 Suprabioin Research Group, and MetalBIO Network ED431D 2017/01)S

    Exploring the Biological Properties of Zn(II) Bis thiosemicarbazone Helicates

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    The design of artificial helicoidal molecules derived from metal ions with biological properties is one of the objectives within metallosupramolecular chemistry. Herein, we report three zinc helicates derived from a family of bis thiosemicarbazone ligands with different terminal groups, Zn(L Me)∙2HO 1, Zn(L Ph)∙2HO 2 and Zn(L PhNO2) 3, obtained by an electrochemical methodology. These helicates have been fully characterized by different techniques, including X-ray diffraction. Biological studies of the zinc(II) helicates such as toxicity assays with erythrocytes and interaction studies with proteins and oligonucleotides were performed, demonstrating in all cases low toxicity and an absence of covalent interaction with the proteins and oligonucleotides. The in vitro cytotoxicity of the helicates was tested against MCF-7 (human breast carcinoma), A2780 (human ovarian carcinoma cells), NCI-H460 (human lung carcinoma cells) and MRC-5 (normal human lung fibroblasts), comparing the IC values with cisplatin. We will try to demonstrate if the terminal substituent of the ligand precursor exerts any effect in toxicity or in the antitumor activity of the zinc helicates

    Serodiagnosis of Echinococcus spp. Infection: Explorative Selection of Diagnostic Antigens by Peptide Microarray

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    Crude or purified, somatic or metabolic extracts of native antigens are routinely used for the serodiagnosis of human helminthic infections. These antigens are often cross-reactive, i.e., recognized by sera from patients infected with heterologous helminth species. To overcome limitations in antigen production, test sensitivity and specificity, chemically synthesized peptides offer a pure and standardized alternative, provided they yield acceptable operative characteristics. Ongoing genome and proteome work create new resources for the identification of antigens. Making use of the growing amount of genomic and proteomic data available in public databases, we tested a bioinformatic procedure for the selection of potentially antigenic peptides from a collection of protein sequences including conceptually translated nucleotide sequence data of Echinococcus multilocularis and E. granulosus (Plathyhelminthes, Cestoda). The in silico selection was combined with high-throughput screening of peptides on microarray and systematic validation of reactive candidates in enzyme-linked immunosorbent assay. Our study proved the applicability of this approach for selection of peptide antigens with good diagnostic characteristics. Our results suggested the pooling of several peptides to reach a high level of sensitivity required for reliable immunodiagnosis

    2 nd Brazilian Consensus on Chagas Disease, 2015

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    Abstract Chagas disease is a neglected chronic condition with a high burden of morbidity and mortality. It has considerable psychological, social, and economic impacts. The disease represents a significant public health issue in Brazil, with different regional patterns. This document presents the evidence that resulted in the Brazilian Consensus on Chagas Disease. The objective was to review and standardize strategies for diagnosis, treatment, prevention, and control of Chagas disease in the country, based on the available scientific evidence. The consensus is based on the articulation and strategic contribution of renowned Brazilian experts with knowledge and experience on various aspects of the disease. It is the result of a close collaboration between the Brazilian Society of Tropical Medicine and the Ministry of Health. It is hoped that this document will strengthen the development of integrated actions against Chagas disease in the country, focusing on epidemiology, management, comprehensive care (including families and communities), communication, information, education, and research

    Pursuing the Elixir of Life: In Vivo Antioxidative Effects of Manganosalen Complexes

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    Manganosalen complexes are coordination compounds that possess a chelating salen-type ligand, a class of bis-Schiff bases obtained by condensation of salicylaldehyde and a diamine. They may act as catalytic antioxidants mimicking both the structure and the reactivity of the native antioxidant enzymes active site. Thus, manganosalen complexes have been shown to exhibit superoxide dismutase, catalase, and glutathione peroxidase activities, and they could potentially facilitate the scavenging of excess reactive oxygen species (ROS), thereby restoring the redox balance in damaged cells and organs. Initial catalytic studies compared the potency of these compounds as antioxidants in terms of rate constants of the chemical reactivity against ROS, giving catalytic values approaching and even exceeding that of the native antioxidative enzymes. Although most of these catalytic studies lack of biological relevance, subsequent in vitro studies have confirmed the efficiency of many manganosalen complexes in oxidative stress models. These synthetic catalytic scavengers, cheaper than natural antioxidants, have accordingly attracted intensive attention for the therapy of ROS-mediated injuries. The aim of this review is to focus on in vivo studies performed on manganosalen complexes and their activity on the treatment of several pathological disorders associated with oxidative damage. These disorders, ranging from the prevention of fetal malformations to the extension of lifespan, include neurodegenerative, inflammatory, and cardiovascular diseases; tissue injury; and other damages related to the liver, kidney, or lungs

    Methanolysis of 2-Cyanopyridine in the Coordination Sphere of Manganese(II). The Structure of Mn4L6Cl2 cluster (L = Methyl Picolinimidate)

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    The reaction of 2-cyanopyridine and Mn(II) in methanol solution led to the formation of a Mn4L6Cl2 cluster 1 containing O-methyl picolimidate as a ligand (L). The coordination of 2-cyanopyridine to the Mn(II) ion as a chelating bidentate ligand activated the CN triple bond which subsequently suffered a nucleophilic attack by CH3OH. Complex 1 was characterized by standard techniques including microanalysis, IR spectroscopy, ESI spectrometry, and magnetic susceptibility measurements. The crystal structure of 1 was determined by X-ray diffraction techniques, and the crystallographic studies revealed a planar-diamond array for 1 where the six monoanionic picolinimidates act as chelating ligands through the two nitrogen atoms

    Route to Cluster Helicates

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    A potentially dianionic helicand ligand exert control over the assembly of metal complexes into common helical structures or supramolecular clusters depending on the oxidation state of the metal. In the tetranuclear cluster dihelicates, a polyhedron of metal ions is the helical axis and the metal cluster is stabilized by two soft donor atoms from the ligand.M.R.B. thanks Xunta de Galicia (PGIDIT03PXI20901PR and PGIDIT04PXIC20902PR) and Ministerio de Educación y Ciencia of Spain (BQU2003-00167) for financial support. M.V. thanks the Xunta de Galicia for support under the “Isidro Parga Pondal Program”.S

    Oxidation Processes in a Phosphine-Thiocarbohydrazone Ligand

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    In this work, we isolated a pentadentate [P2N2S] phosphine-thiocarbohydrazone ligand H2L with a bulky phosphine group in both linker domains that undergoes an oxidation process in solution. This ligand was synthesized by a direct reaction between two equivalents of 2-diphe-nylphosphinebenzaldehyde and one equivalent of thiocarbohydrazide. Two types of crystals de-rived from this ligand were obtained and studied using X-ray diffraction spectroscopy. One structure corresponds to the monooxidized ligand H2L(O) while the other indicates a dioxidation of the compound, H2L(OO)
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