4,807 research outputs found

    A tale of three kingdoms: Members of the Phylum Nematoda independently acquired the detoxifying enzyme cyanase through horizontal gene transfer from plants and bacteria

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    Horizontal gene transfer (HGT) has played an important role in the evolution of nematodes. Among candidate genes, cyanase, which is typically found only in plants, bacteria and fungi, is present in more than 35 members of the Phylum Nematoda, but absent from free-living and clade V organisms. Phylogenetic analyses showed that the cyanases of clade I organisms Trichinella spp., Trichuris spp. and Soboliphyme baturini (Subclass: Dorylaimia) represent a well-supported monophyletic clade with plant cyanases. In contrast, all cyanases found within the Subclass Chromadoria which encompasses filarioids, ascaridoids and strongyloids are homologous to those of bacteria. Western blots exhibited typical multimeric forms of the native molecule in protein extracts of Trichinella spiralis muscle larvae, where immunohisto- chemical staining localized the protein to the worm hypodermis and underlying muscle. Recombinant Trichinella cyanase was bioactive where gene transcription profiles support functional activity in vivo. Results suggest that: (1) independent HGT in parasitic nematodes originated from different Kingdoms; (2) cyanase acquired an active role in the biology of extant Trichinella; (3) acquisition occurred more than 400 million years ago (MYA), prior to the divergence of the Trichinellida and Dioctophymatida, and (4) early, free-living ances- tors of the genus Trichinella had an association with terrestrial plants

    Notes on Ghost Dark Energy

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    We study a phenomenological dark energy model which is rooted in the Veneziano ghost of QCD. In this dark energy model, the energy density of dark energy is proportional to Hubble parameter and the proportional coefficient is of the order ΛQCD3\Lambda^3_{QCD}, where ΛQCD\Lambda_{QCD} is the mass scale of QCD. The universe has a de Sitter phase at late time and begins to accelerate at redshift around zacc∼0.6z_{acc}\sim0.6. We also fit this model and give the constraints on model parameters, with current observational data including SnIa, BAO, CMB, BBN and Hubble parameter data. We find that the squared sound speed of the dark energy is negative, which may cause an instability. We also study the cosmological evolution of the dark energy with interaction with cold dark matter.Comment: 20 pages,10 figures,Correct some typos and add new reference

    Joint content placement and storage allocation based on federated learning in F-RANs

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    Funding: This work was supported in part by Innovation Project of the Common Key Technology of Chongqing Science and Technology Industry (cstc2018jcyjAX0383), the special fund of Chongqing key laboratory (CSTC), and the Funding of CQUPT (A2016-83, GJJY19-2-23, A2020-270).Peer reviewedPublisher PD

    More on QCD Ghost Dark Energy

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    The difference between vacuum energy of quantum fields in Minkowski space and in Friedmann-Robterson-Walker universe might be related to the observed dark energy. The vacuum energy of the Veneziano ghost field introduced to solve the U(1)AU(1)_A problem in QCD is of the form, H+O(H2) H+ {\cal O}(H^2). Based on this, we study the dynamical evolution of a phenomenological dark energy model whose energy density is of the form αH+βH2\alpha H+\beta H^2. In this model, the universe approaches to a de Sitter phase at late times. We fit the model with current observational data including SnIa, BAO, CMB, BBN, Hubble parameter and growth rate of matter perturbation. It shows that the universe begins to accelerate at redshift z∼0.75z\sim 0.75 and this model is consistent with current data. In particular, this model fits the data of growth factor well as the ΛCDM\Lambda CDM model.Comment: 14 pages, 4 figures, 2 table

    Numerical Analysis of Space Effect on the Pile-Anchor Bracing Deep Foundation Pit

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    Volume 8 Issue 1 (January 201

    MalDA, accelerating malaria drug discovery

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    The Malaria Drug Accelerator (MalDA) is a consortium of 15 leading scientific laboratories. The aim of MalDA is to improve and accelerate the early antimalarial drug discovery process by identifying new, essential, druggable targets. In addition, it seeks to produce early lead inhibitors that may be advanced into drug candidates suitable for preclinical development and subsequent clinical testing in humans. By sharing resources, including expertise, knowledge, materials, and reagents, the consortium strives to eliminate the structural barriers often encountered in the drug discovery process. Here we discuss the mission of the consortium and its scientific achievements, including the identification of new chemically and biologically validated targets, as well as future scientific directions

    Nonvolatile memory with molecule-engineered tunneling barriers

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    We report a novel field-sensitive tunneling barrier by embedding C60 in SiO2 for nonvolatile memory applications. C60 is a better choice than ultra-small nanocrystals due to its monodispersion. Moreover, C60 provides accessible energy levels to prompt resonant tunneling through SiO2 at high fields. However, this process is quenched at low fields due to HOMO-LUMO gap and large charging energy of C60. Furthermore, we demonstrate an improvement of more than an order of magnitude in retention to program/erase time ratio for a metal nanocrystal memory. This shows promise of engineering tunnel dielectrics by integrating molecules in the future hybrid molecular-silicon electronics.Comment: to appear in Applied Physics Letter
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