777 research outputs found

    Regioirregular and catalytic Mizoroki-Heck reactions

    Full text link
    [EN] The palladium-catalysed cross-coupling reaction between alkenes and aryl halides (the Mizoroki-Heck reaction) is a powerful methodology to construct new carbon-carbon bonds. However, the success of this reaction is in part hampered by an extremely marked regioselectivity on the double bond, which dictates that electron-poor alkenes react exclusively on the beta-carbon. Here, we show that ligand-free, few-atom palladium clusters in solution catalyse the alpha-selective intramolecular Mizoroki-Heck coupling of iodoaryl cinnamates, and mechanistic studies support the formation of a sterically encumbered cinnamate-palladium cluster intermediate. Following this rationale, the alpha-selective intermolecular coupling of aryl iodides with styrenes is also achieved with palladium clusters encapsulated within fine-tuned and sterically restricted zeolite cavities to produce 1,1-bisarylethylenes, which are further engaged with aryl halides by a metal-free photoredox-catalysed coupling. These ligand-free methodologies significantly expand the chemical space of the Mizoroki-Heck coupling.This work was supported by MINECO (Spain, projects CTQ 2017-86735-P, PID2019-105391GB-C22 and MAT2017-82288-C2-1-P, Severo Ochoa programme SEV-2016-0683 and the Juan de la Cierva programme). F.G.-P. and R.G. thank ITQ for the concession of a contract. J.O.-M. acknowledges the Juan de la Cierva programme for the concession of a contract, and R.P.-R. and J.C.-S. thank the Plan GenT programme (CIDEGENT/2018/044) funded by Generalitat Valenciana. HR STEM measurements were performed at DME-UCA in Cadiz University, with financial support from FEDER/MINECO (PID2019-110018GA-I00 and PID2019-107578GA-I00). We acknowledge ALBA Synchrotron for allocating beamtime and CL AE SS beamline staff for their technical support during our experiment.Garnes-Portoles, F.; Greco, R.; Oliver-Meseguer, J.; Castellanos-Soriano, J.; Jiménez Molero, MC.; Lopez-Haro, M.; Hernåndez-Garrido, JC.... (2021). Regioirregular and catalytic Mizoroki-Heck reactions. Nature Catalysis. 4(4):293-303. https://doi.org/10.1038/s41929-021-00592-3S2933034

    The impact of glucocorticoids and anti-cd20 therapy on cervical human papillomavirus infection risk in women with systemic lupus erythematosus

    Get PDF
    OBJECTIVE: To identify the prevalence and factors associated with cervical human papillomavirus infection in women with systemic lupus erythematosus METHODS: This cross-sectional study collected traditional and systemic lupus erythematosus-related disease risk factors, including conventional and biologic therapies. A gynecological evaluation and cervical cytology screen were performed. Human papillomavirus detection and genotyping were undertaken by PCR and linear array assay. RESULTS: A total of 148 patients were included, with a mean age and disease duration of 42.5±11.8 years and 9.7±5.3 years, respectively. The prevalence of squamous intraepithelial lesions was 6.8%. The prevalence of human papillomavirus infection was 29%, with human papillomavirus subtype 59 being the most frequent. Patients with human papillomavirus were younger than those without the infection (38.2±11.2 vs. 44.2±11.5 years, respectively; p = 0.05), and patients with the virus had higher daily prednisone doses (12.8±6.8 vs. 9.7±6.7 mg, respectively; p = 0.01) and cumulative glucocorticoid doses (14.2±9.8 vs. 9.7±7.3 g, respectively; p = 0.005) compared with patients without. Patients with human papillomavirus infection more frequently received rituximab than those without (20.9% vs. 8.5%, respectively; p = 0.03). In the multivariate analysis, only the cumulative glucocorticoid dose was associated with human papillomavirus infection. CONCLUSIONS: The cumulative glucocorticoid dose may increase the risk of human papillomavirus infection. Although rituximab administration was more frequent in patients with human papillomavirus infection, no association was found. Screening for human papillomavirus infection is recommended in women with systemic lupus erythematosus

    Biofouling Formation and Bacterial Community Structure in Hybrid Moving Bed Biofilm Reactor-Membrane Bioreactors: Influence of Salinity Concentration

    Get PDF
    Two pilot-scale hybrid moving bed biofilm reactor-membrane bioreactors were operated in parallel for the treatment of salinity-amended urban wastewater under 6 hours of hydraulic retention time and 2500 mg L-1 total solids concentration. Two salinity conditions were tested: the constant salinity of 6.5 mS cm-1 electric conductivity (3.6 g L-1 NaCl) and the tidal-like variable salinity with maximum 6.5 mS cm-1 electric conductivity. An investigation was developed on the biofouling produced on the ultrafiltration membrane surface evaluating its bacterial community structure and its potential function in the fouling processes. The results showed that biofouling was clearly affected by salinity scenarios in terms of a-diversity and ÎČ-diversity and bacterial community structure, which confirms lower bacterial diversity under variable salinity conditions with Rhodanobacter and Dyella as dominant phylotypes. Microorganisms identified as bio-mineral formers belonged to genera Bacillus, Citrobacter, and Brevibacterium. These findings will be of help for the prevention and control of biofouling in saline wastewater treatment systems.The authors would like to acknowledge the support given by the Institute of Water Research, the Department of Civil Engineering, the Department of Microbiology and the Department of Mineralogy and Petrology with all from the University of Granada. Additionally, they would like to acknowledge the economic support given by the Government of Spain and the Ministry of Economy and Competitivity under the funding project CTM2013-48154-P and grant BES-2014-067852

    Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

    Get PDF
    Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≄1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≀6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

    Get PDF
    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Un modelo predictivo de comportamiento del consumidor para el diseño de línea de nuevos productos

    Get PDF
    Spa: El objetivo de las firmas es obtener una mayor participación en el Mercado, ofreciendo nuevos productos o mejorando los que ya existen. En la mercadotecnia cuantitativa existe un årea que estudia la correcta configuración de las características que conforman un producto y es conocida como el Problema de Diseño de Producto. Existen diversos algoritmos que atienden este problema. En este trabajo se propone un enfoque de algoritmos evolutivos para atender dicha problemåtica

    A Multiobjective Evolutionary Algorithm for Deriving Final Ranking from a Fuzzy Outranking Relation

    No full text
    Abstract. The multiple criteria aggregation methods allow us to construct a recommendation from a set of alternatives based on the preferences of a decision maker. In some approaches, the recommendation is immediately deduced from the preferences aggregation process. When the aggregation model of preferences is based on the outranking approach, a special treatment is required, but some non-rational violations of the explicit global model of preferences could happen. In this case, the exploitation phase could then be treated as a multiobjective optimization problem. In this paper a new multiobjective evolutionary algorithm, which allows exploiting a known fuzzy outranking relation, is introduced with the purpose of constructing a recommendation for ranking problems. The performance of our algorithm is evaluated on a set of test problems. Computational results show that the multiobjective genetic algorithm-based heuristic is capable of producing high-quality recommendations.
    • 

    corecore