Now showing items 281-300 of 527

    • Caesium Fluoride-Mediated Hydrocarboxylation of Alkenes and Allenes: Scope and Mechanistic Insights 

      Gevorgyan, Ashot; Obst, Marc; Guttormsen, Yngve; Maseras, Feliu; Hopmann, Kathrin Helen; Bayer, Annette (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-11)
      A caesium fluoride-mediated hydrocarboxylation of olefins is disclosed that does not rely on precious transition metal catalysts and ligands. The reaction occurs at atmospheric pressures of CO<sub>2</sub> in the presence of 9-BBN as a stoichiometric reductant. Stilbenes, β-substituted styrenes and allenes could be carboxylated in good yields. The developed methodology can be used for preparation of ...
    • Catalytic Intermolecular Functionalization of Benzimidazoles 

      Hansen, Jørn H; Fjellaksel, Richard (Peer reviewed; Chapter; Bokkapittel, 2019-06-25)
      This chapter describes contemporary strategies for selective catalytic intermolecular functionalization of the benzimidazole scaffold. Functionalization at nitrogen and position C-2 is well developed employing copper, palladium, rhodium, nickel, and cobalt catalysis. Direct CH activation is the predominant approach to C-2 functionalization. Nickel-based catalysts can activate C—O bonds in conjunction ...
    • Closely-related Photobacterium strains comprise the majority of bacteria in the gut of migrating Atlantic cod (Gadus morhua) 

      Le Doujet, Typhaine; De Santi, Concetta; Klemetsen, Terje; Hjerde, Erik; Willassen, Nils Peder; Haugen, Peik (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-17)
      <p><i>Background - </i>The population of Atlantic cod (<i>Gadus morhua</i>), also known as Northeast Arctic cod, migrating Atlantic cod, or simply “skrei,” lives mainly in the Barents Sea and Svalbard waters and migrates in annual cycles to the Norwegian coast in order to spawn eggs during late winter. It is the world’s largest population of Atlantic cod, and the population is distinct from the ...
    • CPPE: An Open-Source C++ and Python Library for Polarizable Embedding 

      Scheurer, Maximilian; Reinholdt, Peter; Kjellgren, Erik Rosendahl; Olsen, Jógvan Magnus Haugaard; Dreuw, Andreas; Kongsted, Jacob (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-03)
      We present a modular open-source library for polarizable embedding (PE) named CPPE. The library is implemented in C++, and it additionally provides a Python interface for rapid prototyping and experimentation in a high-level scripting language. Our library integrates seamlessly with existing quantum chemical program packages through an intuitive and minimal interface. Until now, CPPE has been ...
    • Norcorrole as a Delocalized, Antiaromatic System 

      Conradie, Jeanet; Foroutan-Nejad, Cina; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-19)
      Nickel norcorrole provides an unusual example of a molecule that is strongly antiaromatic according to the magnetic criterion, but which exhibits, according to high-quality DFT calculations, a symmetric, delocalized structure with no difference in bond length between adjacent C<sub>meso</sub>-C<sub>α</sub> bonds. A fragment molecular orbital analysis suggests that these discordant observations are ...
    • Antimicrobial activity of amphipathic α,α-disubstituted β-amino amide derivatives against ESBL–CARBA producing multi-resistant bacteria; effect of halogenation, lipophilicity and cationic character 

      Paulsen, Marianne Hagensen; Ausbacher, Dominik; Bayer, Annette; Engqvist, Magnus; Hansen, Terkel; Haug, Tor; Anderssen, Trude; Andersen, Jeanette Hammer; Sollid, Johanna U. Ericson; Strøm, Morten B. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-06)
      The rapid emergence and spread of multi-resistant bacteria have created an urgent need for new antimicrobial agents. We report here a series of amphipathic α,α-disubstituted β-amino amide derivatives with activity against 30 multi-resistant clinical isolates of Gram-positive and Gram-negative bacteria, including isolates with extended spectrum β-lactamase – carbapenemase (ESBL-CARBA) production. A ...
    • Characterization of an intertidal zone metagenome oligoribonuclease and the role of the intermolecular disulfide bond for homodimer formation and nuclease activity 

      Piotrowski, Yvonne; Berg, Kristel; Klebl, David Paul; Leiros, Ingar; Larsen, Atle Noralf (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-17)
      The gene encoding MG Orn has been identified from a metagenomic library created from the intertidal zone in Svalbard and encodes a protein of 184 amino acid residues. The <i>mg orn</i> gene has been cloned, recombinantly expressed in <i>Escherichia coli</i>, and purified to homogeneity. Biochemical characterization of the enzyme showed that it efficiently degrades short RNA oligonucleotide substrates ...
    • Extreme Scalability of DFT-based QM/MM MD Simulations Using MiMiC 

      Bolnykh, Viacheslav; Olsen, Jógvan Magnus Haugaard; Meloni, Simone; Bircher, Martin Peter; Ippoliti, Emiliano; Carloni, Paolo; Rothlisberger, Ursula (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-09)
      We present a highly scalable DFT-based QM/MM implementation developed within MiMiC, a recently introduced multiscale modeling framework that uses a loose-coupling strategy in conjunction with a multiple-program multiple-data (MPMD) approach. The computation of electrostatic QM/MM interactions is parallelized exploiting both distributed- and shared-memory strategies. Here, we use the efficient CPMD ...
    • Structural intermediates of a DNA-ligase complex illuminate the role of the catalytic metal ion and mechanism of phosphodiester bond formation 

      Williamson, Adele Kim; Leiros, Hanna-Kirsti S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-17)
      DNA ligases join adjacent 5′ phosphate (5′P) and 3′ hydroxyl (3′OH) termini of double-stranded DNA via a three-step mechanism requiring a nucleotide cofactor and divalent metal ion. Although considerable structural detail is available for the first two steps, less is known about step 3 where the DNA-backbone is joined or about the cation role at this step. We have captured high-resolution structures ...
    • Full‐length 16S rRNA gene classification of Atlantic salmon bacteria and effects of using different 16S variable regions on community structure analysis 

      Klemetsen, Terje; Willassen, Nils Peder; Karlsen, Christian René (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-04)
      Understanding fish‐microbial relationships may be of great value for fish producers as fish growth, development and welfare are influenced by the microbial community associated with the rearing systems and fish surfaces. Accurate methods to generate and analyze these microbial communities would be an important tool to help improve understanding of microbial effects in the industry. In this study, ...
    • Improved CRISPR/Cas9 gene editing by fluorescence activated cell sorting of green fluorescence protein tagged protoplasts 

      Petersen, Bent Larsen; Möller, Svenning Rune; Mravec, Jozef; Jørgensen, Bodil; Christensen, Mikkel; Liu, Ying; Wandall, Hans H.; Bennett, Eric Paul; Yang, Zhang (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-17)
      <i>Background</i>: CRISPR/Cas9 is widely used for precise genetic editing in various organisms. CRISPR/Cas9 editing may in many plants be hampered by the presence of complex and high ploidy genomes and inefficient or poorly controlled delivery of the CRISPR/Cas9 components to gamete cells or cells with regenerative potential. Optimized strategies and methods to overcome these challenges are ...
    • Fully Polarizable QM/Fluctuating Charge Approach to Two-Photon Absorption of Aqueous Solutions 

      Di Remigio, Roberto; Giovannini, Tommaso; Ambrosetti, Matteo; Cappelli, Chiara; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-05)
      We present the extension of the quantum/classical polarizable fluctuating charge model to the calculation of single residues of quadratic response functions, as required for the computational modeling of two-photon absorption cross sections. By virtue of a variational formulation of the quantum/classical polarizable coupling, we are able to exploit an atomic orbital-based quasienergy formalism to ...
    • All-electron fully relativistic Kohn-Sham theory for solids based on the Dirac-Coulomb Hamiltonian and Gaussian-type functions 

      Kadek, Marius; Repisky, Michal; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-03)
      We present the first full-potential method that solves the fully relativistic four-component Dirac-Kohn-Sham equation for materials in the solid state within the framework of atom-centered Gaussian-type orbitals (GTOs). Our GTO-based method treats one-, two-, and three-dimensional periodic systems on an equal footing, and allows for a seamless transition to the methodology commonly used in studies ...
    • Response properties of embedded molecules through the polarizable embedding model 

      Steinmann, Casper; Reinholdt, Peter; Nørby, Morten Steen; Kongsted, Jacob; Olsen, Jógvan Magnus Haugaard (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-04)
      The polarizable embedding (PE) model is a fragment‐based quantum‐classical approach aimed at accurate inclusion of environment effects in quantum‐mechanical response property calculations. The aim of this tutorial review is to give insight into the practical use of the PE model. Starting from a set of molecular structures and until you arrive at the final property, there are many crucial details to ...
    • MiMiC: A Novel Framework for Multiscale Modeling in Computational Chemistry 

      Olsen, Jógvan Magnus Haugaard; Bolnykh, Viacheslav; Meloni, Simone; Ippoliti, Emiliano; Bircher, Martin Peter; Carloni, Paolo; Rothlisberger, Ursula (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-18)
      We present a flexible and efficient framework for multiscale modeling in computational chemistry (MiMiC). It is based on a multiple-program multiple-data (MPMD) model with loosely coupled programs. Fast data exchange between programs is achieved through the use of MPI intercommunicators. This allows exploiting the existing parallelization strategies used by the coupled programs while maintaining a ...
    • Features and structure of a cold active N-acetylneuraminic acid lyase 

      Gurung, Man Kumari; Altermark, Bjørn; Helland, Ronny; Smalås, Arne O.; Ræder, Inger Lin Uttakleiv (Journal article; Peer reviewed, 2019-06-11)
      N-acetylneuraminate lyases (NALs) are enzymes that catalyze the reversible cleavage and synthesis of sialic acids. They are therefore commonly used for the production of these high-value sugars. This study presents the recombinant production, together with biochemical and structural data, of the NAL from the psychrophilic bacterium Aliivibrio salmonicida LFI1238 (AsNAL). Our characterization shows ...
    • Design and Biological Evaluation of Antifouling Dihydrostilbene Oxime Hybrids 

      Moodie, Lindon W. K.; Cervin, Gunnar; Trepos, Rozenn; Labriere, Christophe; Hellio, Claire; Pavia, Henrik; Svenson, Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-13)
      By combining the recently reported repelling natural dihydrostilbene scaffold with an oxime moiety found in many marine antifoulants, a library of nine antifouling hybrid compounds was developed and biologically evaluated. The prepared compounds were shown to display a low antifouling effect against marine bacteria but a high potency against the attachment and growth of microalgae down to MIC ...
    • Exploring the transcriptome of luxI- and ΔainS mutants and the impact of N-3-oxo-hexanoyl-L- and N-3-hydroxy- decanoyl-L-homoserine lactones on biofilm formation in Aliivibrio salmonicida 

      Khider, Miriam; Hansen, Hilde; Hjerde, Erik; Johansen, Jostein A; Willassen, Nils Peder (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-30)
      <i>Background</i>: Bacterial communication through quorum sensing (QS) systems has been reported to be important in coordinating several traits such as biofilm formation. In <i>Aliivibrio salmonicida</i> two QS systems the LuxI/R and AinS/R, have been shown to be responsible for the production of eight acyl-homoserine lactones (AHLs) in a cell density dependent manner. We have previously ...
    • Innføring av studentaktive arbeidsformer i seminarundervisningen. Hvilken betydning har dette på læringsutbyttet og klassemiljøet? 

      Netland, Kjell Øystein; Sivertsen, Annfrid; Olufsen, Magne (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-08)
      I denne studien ønsket vi å undersøke hvordan innføring av studentaktive læringsformer i seminarundervisningen påvirket det faglige læringsutbyttet og klassemiljøet i STEM-fag (science, technology, engineering and mathematics). Et randomisert kontrollert studie ble gjennomført i seminarundervisningen i to innføringsemner i fysikk og kjemi ved UiT Norges arktiske universitet. I emnene fulgte ...
    • Genome mapping of seed-borne allergens and immunoresponsive proteins in wheat 

      Juhasz, Angela; Belova, Tatiana; Florides, Chris G; Maulis, Csaba; Fischer, Iris; Gell, Gyongyver; Birinyi, Zsofia; Ong, Jamie; Keeble-Gagnere, Gabriel; Maharajan, Amudha Deepalakshmi; Ma, Wujun; Gibson, Peter; Jia, Jizeng; Lang, Daniel; Mayer, Klaus F X; Spannagl, Manuel; Tye-Din, Jason A.; Appels, Rudi; Olsen, Odd-Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-17)
      Wheat is an important staple grain for humankind globally because of its end-use quality and nutritional properties and its adaptability to diverse climates. For a small proportion of the population, specific wheat proteins can trigger adverse immune responses and clinical manifestations such as celiac disease, wheat allergy, baker’s asthma, and wheat-dependent exercise-induced anaphylaxis (WDEIA). ...