543 research outputs found

    Tandem Thio-Michael Addition/Remote Lactone Activation of 5-Hydroxymethylfurfural-Derived δ-Lactone-Fused Cyclopentenones

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    Funding Information: We thank the Fundação para a Ciência e a Tecnologia (SFRH/BD/120829/2016, SFRH/BD/148211/2019, UIDB/04138/2020, UIDP/04138/2020, PTDC/QUI‐QOR/32008/2017 and GHTM‐UID/04413/2020). The project leading to this application has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 951996. J. A. S. C. thanks the Fundação para a Ciência e a Tecnologia (FCT) for Scientific Employment Stimulus 2020/02383/CEECIND. Publisher Copyright: © 2022 The Authors. ChemSusChem published by Wiley-VCH GmbH.The creation of structurally diverse chemical entities from fairly simple biorefinery products remains a challenge. In this work 5-hydroxymethylfurfural (HMF) was identified as a key synthon for preparing highly complex cyclopentenones (CP) via tandem 1,4-addition/elimination/remote lactone activation to external O- and N-nucleophiles in δ-lactone-fused-CPs hotspots. This scaffold was also reactive enough to be incorporated into model cysteine-peptides in low concentrations, paving the way to a potential translation generating complexity in the synthesis of small peptides. The new enones also exhibited activity against intraerythrocytic Plasmodium falciparum (IC50=1.32 μm).publishersversionpublishe

    Novel universality class of absorbing transitions with continuously varying critical exponents

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    The well-established universality classes of absorbing critical phenomena are directed percolation (DP) and directed Ising (DI) classes. Recently, the pair contact process with diffusion (PCPD) has been investigated extensively and claimed to exhibit a new type of critical phenomena distinct from both DP and DI classes. Noticing that the PCPD possesses a long-term memory effect, we introduce a generalized version of the PCPD (GPCPD) with a parameter controlling the memory effect. The GPCPD connects the DP fixed point to the PCPD point continuously. Monte Carlo simulations show that the GPCPD displays novel type critical phenomena which are characterized by continuously varying critical exponents. The same critical behaviors are also observed in models where two species of particles are coupled cyclically. We suggest that the long-term memory may serve as a marginal perturbation to the ordinary DP fixed point.Comment: 13 pages + 10 figures (Full paper version

    Developing Ontologies withing Decentralized Settings

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    This chapter addresses two research questions: “How should a well-engineered methodology facilitate the development of ontologies within communities of practice?” and “What methodology should be used?” If ontologies are to be developed by communities then the ontology development life cycle should be better understood within this context. This chapter presents the Melting Point (MP), a proposed new methodology for developing ontologies within decentralised settings. It describes how MP was developed by taking best practices from other methodologies, provides details on recommended steps and recommended processes, and compares MP with alternatives. The methodology presented here is the product of direct first-hand experience and observation of biological communities of practice in which some of the authors have been involved. The Melting Point is a methodology engineered for decentralised communities of practice for which the designers of technology and the users may be the same group. As such, MP provides a potential foundation for the establishment of standard practices for ontology engineering

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
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