Synthesis, characterization and application of coordination polymers in heterogeneous photocatalysis

Este trabalho descreve a síntese e caracterização de polímeros de coordenação (PC) e sua aplicação como fotocatalisadores heterogêneos ativos sob a radiação visível, visando a degradação de compostos orgânicos em água. Problemas ambientais têm ocupado posição de destaque na sociedade contemporânea. Dentre eles, o uso de combustíveis fósseis e a remoção de compostos poluentes do meio ambiente têm merecido especial atenção. Uma das alternativas mais indicadas como substituinte dos combustíveis fósseis é a energia solar, por ser limpa, renovável e presente em todo o planeta. O estudo de materiais fotoativos é essencial para aproveitar ao máximo essa fonte. A fotocatálise é um processo que utiliza a energia luminosa para realizar reações químicas. Os PC têm mostrado ótimos resultados na área. Esses são compostos poliméricos cujos monômeros são unidades de coordenação. Neste trabalho foram sintetizados PC formados por diferentes metais de transição e ligantes orgânicos. Dentre eles destacam-se níquel e benzenodicarboxilato (Ni-BDC). Os materiais foram caracterizados por FTIR, DRX, adsorção-dessorção de N2, DRS, TGA, MEV e ICP-OES. Os resultados sugerem a formação de PC inéditos, dotados de sítios de coordenação insaturados, com boa estabilidade térmica, porém com estabilidade em meio aquoso inferior. O ensaio de degradação fotocatalítica de corante evidencia que os materiais são fotoativos na luz visível, apesar da descoloração não ser completa. Este resultado é interessante, pois polímeros de coordenação de níquel ainda são pouco estudados como fotocatalisadores, e esse é um metal barato e abundante.This work describes the synthesis and characterization of coordination polymers (CP) and their application as heterogeneous photocatalysts, under visible radiation, in degradation of organic compounds in water. Environmental issues have taken prominent position in contemporary society. Among them, fossil fuel usage and removal of hazardous compounds deserve special attention. One of the best alternatives to replace fossil fuels is the solar power, which is clean, renewable and ubiquitous throughout the planet. Research on photoactive materials is essential to improve this energy source use. Heterogeneous photocatalysis process uses light energy to induce chemical reactions. CP are exhibiting remarkable results in the field. These are polymeric compounds with coordination units as monomers. In the present work, CP based on different transition metals and organic ligands were synthesized, such as nickel benzenedicarboxylate (Ni-BDC). The materials were characterized by FTIR, XRD, N2 adsorption-desorption, DRS, TGA, SEM and ICPOES. The results suggest the formation of novel CP, endowed with unsaturated metal sites and good thermal stability, however with low stability in aqueous medium. The photocatalytic dye degradation experiments indicate the materials are photoactive under visible light, although the discoloration was not complete. This is an interesting result, considering that the research on nickel coordination polymers as photocatalysts is still scarce

Synthesis, characterization and application of coordination polymers in heterogeneous photocatalysis

Este trabalho descreve a síntese e caracterização de polímeros de coordenação (PC) e sua aplicação como fotocatalisadores heterogêneos ativos sob a radiação visível, visando a degradação de compostos orgânicos em água. Problemas ambientais têm ocupado posição de destaque na sociedade contemporânea. Dentre eles, o uso de combustíveis fósseis e a remoção de compostos poluentes do meio ambiente têm merecido especial atenção. Uma das alternativas mais indicadas como substituinte dos combustíveis fósseis é a energia solar, por ser limpa, renovável e presente em todo o planeta. O estudo de materiais fotoativos é essencial para aproveitar ao máximo essa fonte. A fotocatálise é um processo que utiliza a energia luminosa para realizar reações químicas. Os PC têm mostrado ótimos resultados na área. Esses são compostos poliméricos cujos monômeros são unidades de coordenação. Neste trabalho foram sintetizados PC formados por diferentes metais de transição e ligantes orgânicos. Dentre eles destacam-se níquel e benzenodicarboxilato (Ni-BDC). Os materiais foram caracterizados por FTIR, DRX, adsorção-dessorção de N2, DRS, TGA, MEV e ICP-OES. Os resultados sugerem a formação de PC inéditos, dotados de sítios de coordenação insaturados, com boa estabilidade térmica, porém com estabilidade em meio aquoso inferior. O ensaio de degradação fotocatalítica de corante evidencia que os materiais são fotoativos na luz visível, apesar da descoloração não ser completa. Este resultado é interessante, pois polímeros de coordenação de níquel ainda são pouco estudados como fotocatalisadores, e esse é um metal barato e abundante.This work describes the synthesis and characterization of coordination polymers (CP) and their application as heterogeneous photocatalysts, under visible radiation, in degradation of organic compounds in water. Environmental issues have taken prominent position in contemporary society. Among them, fossil fuel usage and removal of hazardous compounds deserve special attention. One of the best alternatives to replace fossil fuels is the solar power, which is clean, renewable and ubiquitous throughout the planet. Research on photoactive materials is essential to improve this energy source use. Heterogeneous photocatalysis process uses light energy to induce chemical reactions. CP are exhibiting remarkable results in the field. These are polymeric compounds with coordination units as monomers. In the present work, CP based on different transition metals and organic ligands were synthesized, such as nickel benzenedicarboxylate (Ni-BDC). The materials were characterized by FTIR, XRD, N2 adsorption-desorption, DRS, TGA, SEM and ICPOES. The results suggest the formation of novel CP, endowed with unsaturated metal sites and good thermal stability, however with low stability in aqueous medium. The photocatalytic dye degradation experiments indicate the materials are photoactive under visible light, although the discoloration was not complete. This is an interesting result, considering that the research on nickel coordination polymers as photocatalysts is still scarce

Type I IFNs promote cancer cell stemness by triggering the epigenetic regulator KDM1B

Cancer stem cells (CSCs) are a subpopulation of cancer cells endowed with high tumorigenic, chemoresistant and metastatic potential. Nongenetic mechanisms of acquired resistance are increasingly being discovered, but molecular insights into the evolutionary process of CSCs are limited. Here, we show that type I interferons (IFNs-I) function as molecular hubs of resistance during immunogenic chemotherapy, triggering the epigenetic regulator demethylase 1B (KDM1B) to promote an adaptive, yet reversible, transcriptional rewiring of cancer cells towards stemness and immune escape. Accordingly, KDM1B inhibition prevents the appearance of IFN-I-induced CSCs, both in vitro and in vivo. Notably, IFN-I-induced CSCs are heterogeneous in terms of multidrug resistance, plasticity, invasiveness and immunogenicity. Moreover, in breast cancer (BC) patients receiving anthracycline-based chemotherapy, KDM1B positively correlated with CSC signatures. Our study identifies an IFN-I -> KDM1B axis as a potent engine of cancer cell reprogramming, supporting KDM1B targeting as an attractive adjunctive to immunogenic drugs to prevent CSC expansion and increase the long-term benefit of therapy.Type I interferons have been described to have protumor or antitumor functions depending on context. Here the authors show a protumor function for type I interferons in that they promote cancer stem cells by upregulating the chromatin remodeling factor KDM1B

Infective Endocarditis in Patients on Chronic Hemodialysis

International audienceInfective endocarditis (IE) is a common and serious complication in patients receiving chronic hemodialysis (HD)

Infective Endocarditis After Transcatheter Versus Surgical Aortic Valve Replacement

Abstract Background Scarce data are available comparing infective endocarditis (IE) following surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR). This study aimed to compare the clinical presentation, microbiological profile, management, and outcomes of IE after SAVR versus TAVR. Methods Data were collected from the “Infectious Endocarditis after TAVR International” (enrollment from 2005 to 2020) and the “International Collaboration on Endocarditis” (enrollment from 2000 to 2012) registries. Only patients with an IE affecting the aortic valve prosthesis were included. A 1:1 paired matching approach was used to compare patients with TAVR and SAVR. Results A total of 1688 patients were included. Of them, 602 (35.7%) had a surgical bioprosthesis (SB), 666 (39.5%) a mechanical prosthesis, 70 (4.2%) a homograft, and 350 (20.7%) a transcatheter heart valve. In the SAVR versus TAVR matched population, the rate of new moderate or severe aortic regurgitation was higher in the SB group (43.4% vs 13.5%; P < .001), and fewer vegetations were diagnosed in the SB group (62.5% vs 82%; P < .001). Patients with an SB had a higher rate of perivalvular extension (47.9% vs 27%; P < .001) and Staphylococcus aureus was less common in this group (13.4% vs 22%; P = .033). Despite a higher rate of surgery in patients with SB (44.4% vs 27.3%; P < .001), 1-year mortality was similar (SB: 46.5%; TAVR: 44.8%; log-rank P = .697). Conclusions Clinical presentation, type of causative microorganism, and treatment differed between patients with an IE located on SB compared with TAVR. Despite these differences, both groups exhibited high and similar mortality at 1-year follow-up