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Pathogenic and other cytoplasmic DNAs activate the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway to induce inflammation via transcriptional activation by IRF3 and nuclear factor κB (NF-κB), but the functional consequences of exposing cGAS to chromosomes upon mitotic nuclear envelope breakdown are unknown. Here, we show that nucleosomes competitively inhibit DNA-dependent cGAS activation and that the cGAS-STING pathway is not effectively activated during normal mitosis. However, during mitotic arrest, low level cGAS-dependent IRF3 phosphorylation slowly accumulates without triggering inflammation. Phosphorylated IRF3, independently of its DNA-binding domain, stimulates apoptosis through alleviating Bcl-xL-dependent suppression of mitochondrial outer membrane permeabilization. We propose that slow accumulation of phosphorylated IRF3, normally not sufficient for inducing inflammation, can trigger transcription-independent induction of apoptosis upon mitotic aberrations. Accordingly, expression of cGAS and IRF3 in cancer cells makes mouse xenograft tumors responsive to the anti-mitotic agent Taxol. The Cancer Genome Atlas (TCGA) datasets for non-small cell lung cancer patients also suggest an effect of cGAS expression on taxane response.
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Apoptose , DNA/metabolismo , Nucleotidiltransferases/metabolismo , Animais , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Feminino , Humanos , Fator Regulador 3 de Interferon/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos NOD , Mitose , Neoplasias/tratamento farmacológico , Neoplasias/mortalidade , Neoplasias/patologia , Nucleossomos/metabolismo , Nucleotidiltransferases/antagonistas & inibidores , Nucleotidiltransferases/genética , Paclitaxel/farmacologia , Paclitaxel/uso terapêutico , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Transdução de Sinais , Taxa de Sobrevida , Ativação Transcricional , Proteína bcl-X/metabolismoRESUMO
This work aimed to analyse the pharmacogenetic information in the Spanish Drug Regulatory Agency (AEMPS) Summary of Products Characteristics (SmPC), evaluating the presence of pharmacogenetic biomarkers, as well as the associated recommendations. A total of 55.4% of the 1891 drug labels reviewed included information on pharmacogenetic biomarker(s). Pharmacogenomic information appears most frequently in the "antineoplastic and immunomodulating agents", "nervous system", and "cardiovascular system" Anatomical Therapeutic Chemical groups. A total of 509 different pharmacogenetic biomarkers were found, of which CYP450 enzymes accounted for almost 34% of the total drug-biomarker associations evaluated. A total of 3679 drug-biomarker pairs were identified, 102 of which were at the 1A level (PharmGKB® classification system), and 33.33% of these drug-pharmacogenetic biomarker pairs were assigned to "actionable PGx", 12.75% to "informative PGx", 4.9% to "testing recommended", and 4.9% to "testing required". The rate of coincidence in the assigned PGx level of recommendation between the AEMPS and regulatory agencies included in the PharmGKB® Drug Label Annotations database (i.e., the FDA, EMA, SWISS Medic, PMDA, and HCSC) ranged from 45% to 65%, being 'actionable level' the most frequent. On the other hand, discrepancies between agencies did not exceed 35%. This study highlights the presence of relevant pharmacogenetic information on Spanish drug labels, which would help avoid interactions, toxicity, or lack of treatment efficacy.
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Antineoplásicos , Farmacogenética , Humanos , Biomarcadores , Resultado do Tratamento , Rotulagem de Medicamentos , Testes FarmacogenômicosRESUMO
AIMS: The aim of this study was to investigate the association between VKORC1 and CYP2C9 genes polymorphisms and the maintenance dose of warfarin in Peruvian patients. METHODS: An observational study was conducted on outpatients from the Hospital Grau ESSALUD in Lima, Peru. The participants were selected using nonprobabilistic convenience sampling. Inclusion criteria required patients to have been on anticoagulation therapy for >3 months, maintain stable doses of warfarin (consistent dose for at least 3 outpatient visits), and maintain an international normalized ratio within the therapeutic range of 2.5-3.5. DNA samples were obtained from peripheral blood for gene analysis. RESULTS: Seventy patients (mean age of 69.6 ± 13.4 years, 45.7% female) were included in the study. The average weekly warfarin dose was 31.6 ± 15.2 mg. The genotypic frequencies of VKORC1 were as follows: 7.1% (95% confidence interval, 2.4-15.9) for AA; 44.3% (32.4-56.7) for GA; and 48.6% (36.4-60.8) for GG. No deviation from the Hardy-Weinberg equilibrium was observed in the variants studied (P = .56). The mean weekly warfarin doses for AA, GA and GG genotypes were 16.5 ± 2.9, 26.5 ± 9.5 and 37.9 ± 17.1 mg, respectively (P < .001). The genotypic frequencies of CYP2C9 were as follows: 82.8% (72.0-90.8) for CC (*1/*1); 4.3% (1.0-12.0) for CT (*1/*2); and 12.9% (6.1-23.0) for TT (*2/*2). We did not find a significant association between the CYP2C9 gene polymorphism and the dose of warfarin. CONCLUSIONS: The AA genotype of the VKORC1 gene was associated with a lower maintenance dose of warfarin in Peruvian patients.
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Anticoagulantes , Varfarina , Humanos , Feminino , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Masculino , Citocromo P-450 CYP2C9/genética , Peru , Anticoagulantes/efeitos adversos , Vitamina K Epóxido Redutases/genética , Polimorfismo Genético , Genótipo , Coeficiente Internacional NormatizadoRESUMO
BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has induced a significant global concern on mental health. However few studies have measured the ability of individuals to "withstand setbacks, adapt positively, and bounce back from adversity" on a global scale. We aimed to examine the level of resilience, its determinants, and its association with maladaptive coping behaviours during the pandemic. METHODS: The Association of Pacific Rim Universities (APRU) conducted a global survey involving 26 countries by online, self-administered questionnaire (October 2020-December 2021). It was piloted-tested and validated by an expert panel of epidemiologists and primary care professionals. We collected data on socio-demographics, socioeconomic status, clinical information, lifestyle habits, and resilience levels measured by the Brief Resilience Scale (BRS) among adults aged ≥ 18 years. We examined factors associated with low resilience level, and evaluated whether low resilience was correlated with engagement of maladaptive coping behaviours. RESULTS: From 1,762 surveys, the prevalence of low resilience level (BRS score 1.00-2.99) was 36.4% (America/Europe) and 24.1% (Asia Pacific). Young age (18-29 years; adjusted odds ratio [aOR] = 0.31-0.58 in older age groups), female gender (aOR = 1.72, 95% C.I. = 1.34-2.20), poorer financial situation in the past 6 months (aOR = 2.32, 95% C.I. = 1.62-3.34), the presence of one (aOR = 1.56, 95% C.I. = 1.19-2.04) and more than two (aOR = 2.32, 95% C.I. = 1.59-3.39) medical conditions were associated with low resilience level. Individuals with low resilience were significantly more likely to consume substantially more alcohol than usual (aOR = 3.84, 95% C.I. = 1.62-9.08), take considerably more drugs (aOR = 12.1, 95% C.I. = 2.72-54.3), buy supplements believed to be good for treating COVID-19 (aOR = 3.34, 95% C.I. = 1.56-7.16), exercise less than before the pandemic (aOR = 1.76, 95% C.I. = 1.09-2.85), consume more unhealthy food than before the pandemic (aOR = 2.84, 95% C.I. = 1.72-4.67), self-isolate to stay away from others to avoid infection (aOR = 1.83, 95% C.I. = 1.09-3.08), have an excessive urge to disinfect hands for avoidance of disease (aOR = 3.08, 95% C.I. = 1.90-4.99) and transmission (aOR = 2.54, 95% C.I. = 1.57-4.10). CONCLUSIONS: We found an association between low resilience and maladaptive coping behaviours in the COVID-19 pandemic. The risk factors identified for low resilience in this study were also conditions known to be related to globalization-related economic and social inequalities. Our findings could inform design of population-based, resilience-enhancing intervention programmes.
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COVID-19 , Adulto , Humanos , Feminino , Idoso , COVID-19/epidemiologia , Pandemias , Adaptação Psicológica , Inquéritos e Questionários , Saúde MentalRESUMO
While colloidal chemistry provides ways to obtain a great variety of nanoparticles with different shapes, sizes, material compositions, and surface functions, their controlled deposition and combination on arbitrary positions of substrates remain a considerable challenge. Over the last ten years, optical printing arose as a versatile method to achieve this purpose for different kinds of nanoparticles. In this article, we review the state of the art of optical printing of single nanoparticles and discuss its strengths, limitations, and future perspectives by focusing on four main challenges: printing accuracy, resolution, selectivity, and nanoparticle photostability.
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Hypoxia-inducible factor 1 α (HIF1α), a regulator of metabolic change, is required for the survival and differentiation potential of mesenchymal stem/stromal cells (MSC). Its role in MSC immunoregulatory activity, however, has not been completely elucidated. In the present study, we evaluate the role of HIF1α on MSC immunosuppressive potential. We show that HIF1α silencing in MSC decreases their inhibitory potential on Th1 and Th17 cell generation and limits their capacity to generate regulatory T cells. This reduced immunosuppressive potential of MSC is associated with a metabolic switch from glycolysis to OXPHOS and a reduced capacity to express or produce some immunosuppressive mediators including Intercellular Adhesion Molecule (ICAM), IL-6, and nitric oxide (NO). Moreover, using the Delayed-Type Hypersensitivity murine model (DTH), we confirm, in vivo, the critical role of HIF1α on MSC immunosuppressive effect. Indeed, we show that HIF1α silencing impairs MSC capacity to reduce inflammation and inhibit the generation of pro-inflammatory T cells. This study reveals the pivotal role of HIF1α on MSC immunosuppressive activity through the regulation of their metabolic status and identifies HIF1α as a novel mediator of MSC immunotherapeutic potential.
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Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Imunossupressores/metabolismo , Células-Tronco Mesenquimais/metabolismo , Animais , Diferenciação Celular/fisiologia , Células Cultivadas , Citocinas/metabolismo , Tolerância Imunológica/fisiologia , Inflamação/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Linfócitos T Reguladores/metabolismo , Células Th1 , Células Th17/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Syringotropic mycosis fungoides is a very rare variant of cutaneous T-cell lymphomas characterised by prominent involvement of the eccrine glands. Hypereosinophilic syndrome refers to a rare group of conditions that are associated with persistent eosinophilia with organ involvement. It is classified into idiopathic, primary and secondary (reactive). We report herein an unusual case of hypereosinophilic syndrome with great impact on morbidity, which developed in a patient with human immunodeficiency virus infection and long-time misdiagnosed syringotropic mycosis fungoides.
Assuntos
Infecções por HIV/complicações , Síndrome Hipereosinofílica/patologia , Micose Fungoide/patologia , Neoplasias Cutâneas/patologia , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
AIMS: Evaluate the effect of varying the droplet size of microspheres charged with thyme essential oil (TEO-MS) on their swelling (Sw), release rate (%RR) and in vitro antifungal activity against Saprolegnia sp. METHODS: TEO-MS obtained by ionic gelation were characterised through SEM microscopy and X-ray microtomography. Their Sw and RR% were evaluated at simulated fish-gastrointestinal conditions using gravimetric and spectrophotometric techniques. RESULTS: For all evaluated droplet sizes (p ≥ 0.05), TEO was heterogeneously distributed inside of the MS and TEO-MS experimented agglomeration and sphericity loss after the drying process. Under gastric conditions, the acid pH (2.9) limited the Sw (50-100%) of TEO-MS, generating a low RR% (14-18%). Contrary, the slightly alkaline intestinal pH (8.1) favoured the Sw (â¼3.2 to 3.8 times) and therefore the RR% (42-63%). CONCLUSIONS: TEO-MS (5-100 mg/mL) presented antifungal capacity onto Saprolegnia sp. after the simulated fish digestion, being the small droplet size once the most effective.
Assuntos
Antifúngicos/administração & dosagem , Sistemas de Liberação de Medicamentos , Microesferas , Óleos Voláteis , Saprolegnia/efeitos dos fármacos , Thymus (Planta)/química , Animais , Química Farmacêutica/métodos , Liberação Controlada de Fármacos , Peixes , Gastroenteropatias/tratamento farmacológico , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Microscopia Eletrônica de Varredura , Modelos Teóricos , Tamanho da Partícula , Espectrofotometria , Microtomografia por Raio-XRESUMO
Nickelacyclobutanes are mostly invoked as reactive intermediates in the reaction of nickel carbenes and olefins to yield cyclopropanes. Nevertheless, early work suggested that other decomposition routes such as ß-hydride elimination and even metathesis could be accessible. Herein, we report the isolation and characterization of a stable pentacoordinated nickelacyclobutane incorporated in a pincer complex. The coordination of different coligands to the nickelacyclobutane determines its selective decomposition along cyclopropanation, metathesis or apparent ß-hydride elimination pathways. DFT calculations shed light on the mechanism of these different pathways.
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The unfolded protein response (UPR) regulates cell fate following exposure of cells to endoplasmic reticulum stresses. PERK, a UPR protein kinase, regulates protein synthesis and while linked with cell survival, exhibits activities associated with both tumor progression and tumor suppression. For example, while cells lacking PERK are sensitive to UPR-dependent cell death, acute activation of PERK triggers both apoptosis and cell cycle arrest, which would be expected to contribute tumor suppressive activity. We have evaluated these activities in the BRAF-dependent melanoma and provide evidence revealing a complex role for PERK in melanoma where a 50% reduction is permissive for BrafV600E-dependent transformation, while complete inhibition is tumor suppressive. Consistently, PERK mutants identified in human melanoma are hypomorphic with dominant inhibitory function. Strikingly, we demonstrate that small molecule PERK inhibitors exhibit single agent efficacy against BrafV600E-dependent tumors highlighting the clinical value of targeting PERK.
Assuntos
Melanoma/genética , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Supressoras de Tumor/genética , eIF-2 Quinase/genética , Apoptose/efeitos dos fármacos , Apoptose/genética , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , Transformação Celular Neoplásica/efeitos dos fármacos , Retículo Endoplasmático/genética , Retículo Endoplasmático/patologia , Dosagem de Genes/genética , Haploinsuficiência/genética , Humanos , Melanoma/tratamento farmacológico , Melanoma/patologia , Mutação , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Bibliotecas de Moléculas Pequenas/administração & dosagem , Proteínas Supressoras de Tumor/biossíntese , Resposta a Proteínas não Dobradas/genética , eIF-2 Quinase/antagonistas & inibidores , eIF-2 Quinase/biossínteseRESUMO
Segmental ischemic colitis is an uncommon disease in young patients, being usually associated to drug abuse, infectious or autoimmune diseases. We present a case that, in spite of a complete diagnostic study, had repeatedly two attacks of intestinal necrosis during his admission.
Assuntos
Intestinos/patologia , Colite , Doenças do Colo/diagnóstico por imagem , Doenças do Colo/patologia , Doenças do Colo/cirurgia , Humanos , Ileostomia , Íleo/cirurgia , Intestinos/diagnóstico por imagem , Intestinos/cirurgia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Necrose , Tomografia Computadorizada por Raios XRESUMO
Interleukin 24 (IL-24) is an important pleiotropic immunoregulatory cytokine, whose gene is located in human chromosome 1q32-33. IL-24's signaling pathways have diverse biological functions related to cell differentiation, proliferation, development, apoptosis, and inflammation, placing it at the center of an active area of research. IL-24 is well known for its apoptotic effect in cancer cells while having no such effect on normal cells. IL-24 can also be secreted by both immune and non-immune cells. Downstream effects of IL-24, after binding to the IL-20 receptor, can occur dependently or independently of the JAK/STAT signal transduction pathway, which is classically involved in cytokine-mediated activities. After exogenous addition of IL-24, apoptosis is induced in tumor cells independently of the JAK/STAT pathway. We have shown that IL-24 binds to Sigma 1 Receptor and this event induces endoplasmic reticulum stress, calcium mobilization, reactive oxygen species generation, p38MAPK activity, and ceramide production. Here we review IL-24's role in autoimmunity, infectious disease response, wound repair, and vascular disease. Detailed understanding of the pleiotropic roles of IL-24 signaling can assist in the selection of more accurate therapeutic approaches, as well as targeting of appropriate cell types in treatment strategy development, and ultimately achieve desired therapeutic effects.
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Imunoterapia , Interleucinas/metabolismo , Animais , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/imunologia , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/terapia , Resistência à Doença/genética , Resistência à Doença/imunologia , Expressão Gênica , Humanos , Sistema Imunitário/citologia , Sistema Imunitário/imunologia , Sistema Imunitário/metabolismo , Imunidade Inata , Imunoterapia/métodos , Inflamação/genética , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/terapia , Interleucinas/química , Interleucinas/genética , Metástase Neoplásica , Neoplasias/genética , Neoplasias/imunologia , Neoplasias/metabolismo , Neoplasias/terapia , Neovascularização Fisiológica/genética , Ligação Proteica , Receptores de Interleucina/metabolismo , Transdução de Sinais , Cicatrização/genética , Cicatrização/imunologiaRESUMO
Spontaneous rupture of a liver hemangioma is a very uncommon disease, but extremely seriousness because it is associated to a 75% of mortality caused by hipovolemic shock. A case of an spontaneous rupture of liver hemangioma, which was previously unknow, is presented.
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Hemangioma/complicações , Hemangioma/diagnóstico por imagem , Hepatopatias/complicações , Hepatopatias/diagnóstico por imagem , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/diagnóstico por imagem , Idoso , Evolução Fatal , Hemangioma/cirurgia , Hepatectomia , Humanos , Hepatopatias/cirurgia , Neoplasias Hepáticas/cirurgia , Masculino , Ruptura EspontâneaAssuntos
Granuloma Piogênico/patologia , Doenças da Unha/patologia , Unhas/patologia , Pólipos/patologia , Veias/patologia , Idoso , Biópsia , Diagnóstico Diferencial , Granuloma Piogênico/cirurgia , Humanos , Masculino , Doenças da Unha/cirurgia , Unhas/cirurgia , Pólipos/cirurgia , Valor Preditivo dos Testes , Veias/cirurgiaRESUMO
Biomphalaria straminea is a freshwater gastropod native to South America and used in toxicological assessments. Our aim was to estimate 48 h-LC50 and sub-chronic effects after the exposure to low concentrations of chlorpyrifos as commercial formulation (CF) and active ingredient (AI) on B. straminea adult, embryos and juveniles. Concentrations between 1 and 5000 µg L-1 were chosen for acute exposures and 0.1 and 1 µg L-1 for the sub-chronic one. After 14 days biochemical parameters, viability and sub-populations of hemocytes, reproductive parameters, embryotoxicity and offspring' survival were studied. Egg masses laid between day 12 and 14 were separated to continue the exposure and the embryos were examined daily. Offspring' survival and morphological changes were registered for 14 days after hatching. 48 h-LC50, NOEC and LOEC were similar between CF and AI, however the CF caused more sub-lethal effects. CF but not the AI decreased carboxylesterases, catalase and the proportion of hyalinocytes with respect to the total hemocytes, and increased superoxide dismutase and the % of granulocytes with pseudopods. Also CF caused embryotoxicity probably due to the increase of embryos' membrane permeability. Acetylcholinesterase, superoxide dismutase, hemocytes sub-populations, the time and rate of hatching and juveniles' survival were the most sensitive biomarkers. We emphasize the importance of the assessment of a battery of biomarkers as a useful tool for toxicity studies including reproduction parameters and immunological responses. Also, we highlight the relevance of incorporating the evaluation of formulations in order to not underestimate the effects of pesticides on the environment.
Assuntos
Biomarcadores , Biomphalaria , Clorpirifos , Embrião não Mamífero , Inseticidas , Poluentes Químicos da Água , Clorpirifos/toxicidade , Animais , Biomphalaria/efeitos dos fármacos , Inseticidas/toxicidade , Biomarcadores/metabolismo , Poluentes Químicos da Água/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Hemócitos/efeitos dos fármacos , Dose Letal Mediana , Reprodução/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Catalase/metabolismoRESUMO
Catalytic olefin hydrogenation is ubiquitous in organic synthesis. In most proposed homogeneous catalytic cycles, reactive M-H bonds are generated either by oxidative addition of H2 to a metal centre or by deprotonation of a non-classical metal dihydrogen (M-H2) intermediate. Here we provide evidence for an alternative H2-activation mechanism that instead involves direct ligand-to-ligand hydrogen transfer (LLHT) from a metal-bound H2 molecule to a metal-coordinated olefin. An unusual pincer ligand that features two phosphine ligands and a central olefin supports the formation of a non-classical Ni-H2 complex and the Ni(alkyl)(hydrido) product of LLHT, in rapid equilibrium with dissolved H2. The usefulness of this cooperative H2-activation mechanism for catalysis is demonstrated in the semihydrogenation of diphenylacetylene. Experimental and computational mechanistic investigations support the central role of LLHT for H2 activation and catalytic semihydrogenation. The product distribution obtained is largely determined by the competition between (E)-(Z) isomerization and catalyst degradation by self-hydrogenation.
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Nickel carbenes are attracting attention for the development of more sustainable catalysts, among others, for cyclopropanation. Intramolecular trapping of a nickel carbene intermediate with an olefin incorporated in a P(C=C)P Ni pincer complex had previously allowed the isolation of a nickelacyclobutane intermediate and a detailed characterization of its reactivity. Herein, we report the reactivity of related nickel pincer complexes bearing a ketone P(C=O)P or an imine P(C=N)P with diazoalkanes as the carbene precursor. The observed reactivity suggests, in both cases, the reaction of the transient nickel carbene with one of the phosphine arms to form phosphorus ylides that subsequently react with the unsaturated backbone. Density functional theory (DFT) calculations are used to shed light on the mechanisms of these reactions.
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Deep eutectic solvents (DES) formed using choline chloride (ChCl), p-toluenesulfonic acid (pTSA) of stoichiometry ChCl: pTSA (1:1) and (1:2), and its ternary eutectic mixtures with phosphoric acid (PA) 85% as an additive (ChCl: pTSA: PA) were evaluated for cellulose nanocrystal (CNC) isolation. Initially, the hydrolytic efficiency to produce CNC of each DES was compared before and after adding phosphoric acid by Hammett acidity parameters and the Gutmann acceptor number. Moreover, different DES molar ratios and reaction time were studied at 80°C for CNC optimization. The nanomaterial characteristics were analyzed by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The ternary eutectic mixture ChCl: pTSA: PA molar ratio (1:1:1.35) was chosen as a suitable recyclable ternary system at the laboratory scale. A CNC yield of about 80% was obtained from the hydrolysis of commercial cellulose in five cycles of recovery, but it dropped to 35% in pre-pilot scaling. However, no variation in the average size of the resulting CNC was observed (132 ± 50 nm x 23 ± 4 nm), which presented high thermal stability (Tmax 362°C) and high crystallinity of about 80% after 3 h of reaction time.
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Metal-ligand cooperation can facilitate the activation of chemical bonds, opening reaction pathways of interest for catalyst development. In this context, olefins occupying the central position of a diphosphine pincer ligand (PC=CP) are emerging as reversible H atom acceptors, e.g., for H2 activation. Here, we report on the reactivity of nickel complexes of PC=CP ligands with a terminal alkyne, for which two competing pathways are observed. First, cooperative and reversible C-H bond activation generates a Ni(II) alkyl/alkynyl complex as the kinetic product. Second, in the absence of a bulky substituent on the olefin, two alkyne molecules are incorporated in the ligand structure to form a conjugated triene bound to Ni(0). The mechanisms of these processes are studied by density functional theory calculations supported by experimental observations.