143 research outputs found

    Trispyrazolylborate Ligands Supported on Vinyl Addition Polynorbornenes and Their Copper Derivatives as Recyclable Catalysts

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    Polynorbornenes prepared by vinyl addition poly- merization and bearing pendant alkenyl groups serve as skeletons to support trispyrazolylborate ligands (Tpx) built at those alkenyl sites. Reaction with CuI in acetonitrile led to VA-PNB–TpxCu(NCMe) (VA-PBN = vinyl addition polynorbor- nene) with a 0.8–1.4 mmol incorporation of Cu per gram of polymer. The presence of tetracoordinated copper(I) ions was been assessed by FTIR studies on the corresponding VA-PNB-TpxCu(CO) adducts, in agreement with those on discrete TpxCu(CO). The new materials were employed as heteroge- neous catalysts in several carbene- and nitrene-transfer reac- tions, showing a behavior similar to that of the homogene- ous counterparts but also being recycled several times main- taining a high degree of activity and selectivity. This is the first example of supported Tpx ligands onto polymeric sup- ports with catalytic applications.MINECO (CTQ2017-82893-C2-1-R, CTQ2016-80913-P and Red Intecat CTQ2016-81923-REDC)Junta de Castilla y León (VA051P17, VA062G18)European Union (CHAOS COST ACTION CA-15106)

    El sentido de la cultura en el desarrollo de los pueblos

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    This article aims to highlight the role that culture plays in the economic and social development of today's societies. Despite being woven as a conceptualization from the economicist and humanist paradigms, it is evident that for both optics it is a positive affectation of the culture on the economy, so much that in the literature they are references to the economy of the culture. Concomitantly, it seeks to establish a concept that allows us to approach culture not only as a physical space, but in turn is temporary and psychosocial where society materializes its world.Este artículo apunta a resaltar el rol que la cultura juega en el desarrollo económico y social de las sociedades actuales. A pesar de tejerse como una conceptualización desde los paradigmas economicistas y humanista, se evidencia que para ambas ópticas se trata de una afectación positiva de la cultura sobre la economía, tanto que en la literatura se encuentran referencias a la economía de la cultura. De manera concomitante se busca establecer un concepto que permita abordar a la cultura no solamente como un espacio físico, sino que a su vez es temporal y psicosocial donde la sociedad materializa su mundo

    El sentido de la cultura en el desarrollo de los pueblos.

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    This article aims to highlight the role that culture plays in the economic and social development of today ‘s societies. Despite being woven as a conceptualization from the economicist and humanist paradigms, it is evident that for both optics it is apositive affectation of the culture on the economy, so much that in the literaturethey are references to the economy of the culture. Concomitantly, it seeks to establish a concept that allows us to approach culture not only as a physical space, but in turn is temporary and psychosocial where society materializes its world.Este  artículo  apunta  a   resaltar  el rol que la cultura juega en el desarrollo económico y social de las sociedades  actuales.  A  pesar de tejerse como una conceptualización desde los paradigmas economicistas y humanista, se evidencia que para ambas ópticas se trata de una afectación positiva de la cultura sobre la economía, tanto que en la literatura se encuentran  referencias a la economía de la cultura. De manera concomitante se busca establecer un concepto que permita abordar a la cultura no solamente como un espacio físico, sino que a su vez es temporal y psicosocial donde la sociedad materializa su mundo

    Anti-cyanobacterial activity of Moringa oleifera seeds

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    Filtrates from crushed Moringa oleifera seeds were tested for their effects on growth and Photosystem II efficiency of the common bloom-forming cyanobacterium Microcystis aeruginosa. M. aeruginosa populations exhibited good growth in controls and treatments with 4- and 8-mg crushed Moringa seeds per liter, having similar growth rates of 0.50 (±0.01) per day. In exposures of 20- to 160-mg crushed Moringa seeds L−1, growth rates were negative and on average −0.23 (±0.05) .day−1. Presumably, in the higher doses of 20- to 160-mg crushed seeds per liter, the cyanobacteria died, which was supported by a rapid drop in the Photosystem II efficiency (ΦPSII), while the ΦPSII was high and unaffected in 0, 4, and 8 mg L−1. High-density populations of M. aeruginosa (chlorophyll-a concentrations of ∼270 µg L−1) were reduced to very low levels within 2 weeks of exposure to ≥80-mg crushed seeds per liter. At the highest dosage of 160 mg L−1, the ΦPSII dropped to zero rapidly and remained nil during the course of the experiment (14 days). Hence, under laboratory conditions, a complete wipeout of the bloom could be achieved. This is the first study that yielded evidence for cyanobactericidal activity of filtrate from crushed Moringa seeds, suggesting that Moringa seed extracts might have a potential as an effect-oriented measure lessening cyanobacterial nuisance

    Historical Y. pestis Genomes Reveal the European Black Death as the Source of Ancient and Modern Plague Pandemics

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    © 2016 Elsevier Inc.Ancient DNA analysis has revealed an involvement of the bacterial pathogen Yersinia pestis in several historical pandemics, including the second plague pandemic (Europe, mid-14th century Black Death until the mid-18th century AD). Here we present reconstructed Y. pestis genomes from plague victims of the Black Death and two subsequent historical outbreaks spanning Europe and its vicinity, namely Barcelona, Spain (1300-1420 cal AD), Bolgar City, Russia (1362-1400 AD), and Ellwangen, Germany (1485-1627 cal AD). Our results provide support for (1) a single entry of Y. pestis in Europe during the Black Death, (2) a wave of plague that traveled toward Asia to later become the source population for contemporary worldwide epidemics, and (3) the presence of an historical European plague focus involved in post-Black Death outbreaks that is now likely extinct
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