Now showing items 289-308 of 527

    • MabCent: Arctic marine bioprospecting in Norway 

      Svenson, Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The deep waters surrounding the coastline of the northern parts of Norway represent an exciting biotope for marine exploration. Dark and cold Arctic water generates a hostile environment where the ability to adapt is crucial to survival. These waters are nonetheless bountiful and a diverse plethora of marine organisms thrive in these extreme conditions, many with the help of specialised ...
    • Magnetic Diversity in Heteroisocorroles: Aromatic Pathways in 10-Heteroatom-Substituted Isocorroles 

      Foroutan-Nejad, Cina; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-21)
      A recent study on magnetically induced currents in 10-isocorrole derivatives indicated that both the free-base and metal-complexed forms of the unsubstituted macrocycle are homoaromatic. Furthermore, depending on the substituents at the 10-position, the aromatic character was found to swing between substantially homoaromatic to substantially antihomoaromatic. Heteroisocorroles, in which the saturated ...
    • Magnetic properties with multiwavelets and DFT: The complete basis set limit achieved 

      Jensen, Stig Rune; Flå, Tor; Jonsson, Dan Johan; Monstad, Rune Sørland; Ruud, Kenneth; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-11)
      Multiwavelets are emerging as an attractive alternative to traditional basis sets such as Gaussian-type orbitals and plane waves. One of their distinctive properties is the ability to reach the basis set limit (often a chimera for traditional approaches) reliably and consistently by fixing the desired precision ε. We present our multiwavelet implementation of the linear response formalism, applied ...
    • Main-Group-Element Isophlorin Complexes Revisited: The Question of a Subvalent Central Atom 

      Conradie, Jeanet; Brothers, Penelope Jane; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-15)
      A careful density functional theory reexamination of the geometric and electronic structures of reduced main-group porphyrin complexes E(Por)L2 (E = Si or Ge; L = pyridine or tetrahydrofuran), B2(Por), and C2(Por) has confirmed these as pure isophlorin derivatives with normal-valent coordinated central atoms. Only axially unligated Ge(Por) and the dications [B2(Por)]2+ and [C2(Por)]2+ feature aromatic ...
    • The MAR databases: development and implementation of databases specific for marine metagenomics 

      Klemetsen, Terje; Raknes, Inge A.; Fu, Juan; Agafonov, Alexander; Balasundaram, Sudhagar V.; Tartari, Giacomo; Robertsen, Espen; Willassen, Nils Peder (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-02)
      We introduce the marine databases; <i>MarRef, MarDB</i> and <i>MarCat</i> (https://mmp.sfb.uit.no/databases/), which are publicly available resources that promote marine research and innovation. These data resources, which have been implemented in the Marine Metagenomics Portal (MMP) (https://mmp.sfb.uit.no/), are collections of richly annotated and manually curated contextual (metadata) and sequence ...
    • Mechanistic Insights into Carbamate Formation from CO2 and Amines: The Role of Guanidine–CO2 Adducts, 

      Mannisto, Jere K.; Pavlovic, Ljiljana; Tiainen, Tony; Nieger, Martin; Sahari, Aleksi; Hopmann, Kathrin Helen; Repo, Timo (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-02)
      Capture of CO<sub>2</sub> by amines is an attractive synthetic strategy for the formation of carbamates. Such reactions can be mediated by superbases, such as 1,1,3,3-tetramethylguanidine (TMG), with previous implications that zwitterionic superbase–CO<sub>2</sub> adducts are able to actively transfer the carboxylate group to various substrates. Here we report a detailed investigation of zwitterionic ...
    • Mechanistic Insights into Copper-Catalyzed Carboxylations 

      Obst, Marc; Gevorgyan, Ashot; Bayer, Annette; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-02)
      The copper-NHC-catalyzed carboxylation of organoboranes with CO<sub>2</sub> was investigated using computational and experimental methods. The DFT and DLPNO-CCSD(T) results indicate that nonbenzylic substrates are converted via an inner-sphere carboxylation of an organocopper intermediate, whereas benzylic substrates may simultaneously proceed along both inner- and outer-sphere CO<sub>2</sub> insertion ...
    • Mechanistic Investigations of the Asymmetric Hydrogenation of Enamides with Neutral Bis(phosphine) Cobalt Precatalysts 

      Mendelsohn, Lauren N.; Pavlovic, Ljiljana; Zhong, Hongyu; Friedfeld, Max R.; Shevlin, Michael; Hopmann, Kathrin Helen; Chirik, Paul J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-11)
      The mechanism of the asymmetric hydrogenation of prochiral enamides by well-defined, neutral bis(phosphine) cobalt(0) and cobalt(II) precatalysts has been explored using(R,R)-<sup>iPr</sup>DuPhos ((R,R)-<sup>iPr</sup>DuPhos = (+)-1,2-bis[(2R,5R)-2,5-diisopropylphospholano]benzene) as a representative chiral bis(phosphine) ligand. A series of (R,R)-(<sup>iPr</sup>DuPhos)Co(enamide) (enamide = ...
    • A Mechanistic Study of the Cu-catalyzed N-arylation of Hydantoin with Aryl(TMP)iodonium Salts 

      Nova Flores, Ainara; Berntsen, Linn Neerbye (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-16)
      The use of diaryliodonium salts in organic reactions has rapidly increased in the last decade because of their efficiency in arylation reactions. Despite this, mechanistic investigations are still scarce, particularly for copper catalyzed N-arylation reactions. Recently, we published the use of the unsymmetrical aryl(TMP)iodonium salts (TMP=2,4,6-trimethoxyphenyl) for the selective Cu-catalyzed ...
    • Metallaaromaticity - a protean world 

      Cuyacot, Ben Joseph R.; Badri, Zahra; Ghosh, Abhik; Foroutan-Nejad, Cina (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-01)
      The nature of magnetically induced current densities (MICD) of metallabenzenes and related compounds has been examined with relativistic DFT calculations to assess the magnetic aromaticity of the molecules. The origin of the total MICD has been analyzed in terms of individual molecular orbital (MO) contributions. Our study reveals that the s-framework of the molecules always makes a diamagnetic ...
    • Metallo-β-Lactamase Inhibitor Phosphonamidate Monoesters 

      Palica, Katarzyna; Vorácová, Manuela; Skagseth, Susann; Andersson Rasmussen, Anna; Allander, Lisa; Hubert, Madlen; Sandegren, Linus; Leiros, Hanna-Kirsti S.; Andersson, Hanna; Erdélyi, Máté (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-25)
      Being the second leading cause of death and the leading cause of disability-adjusted life years worldwide, infectious diseases remain-contrary to earlier predictions-a major consideration for the public health of the 21st century. Resistance development of microbes to antimicrobial drugs constitutes a large part of this devastating problem. The most widely spread mechanism of bacterial resistance ...
    • Metallo-β-lactamase inhibitors by bioisosteric replacement: preparation, activity and binding 

      Skagseth, Susann; Akhter, Sundus; Paulsen, Marianne H; Muhammad, Zeeshan; Samuelsen, Ørjan; Leiros, Hanna-Kirsti S.; Bayer, Annette (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-14)
      Bacterial resistance is compromising the use of β-lactam antibiotics including carbapenems. The main resistance mechanism against β-lactams is hydrolysis of the β-lactam ring mediated by serine- or metallo-β-lactamases (MBLs). Although several inhibitors of MBLs have been reported, none has been developed into a clinically useful inhibitor. Mercaptocarboxylic acids are among the most prominent ...
    • Methanotroph populations and CH 4 oxidation potentials in High Arctic peat are altered by herbivory induced vegetation change 

      Rainer, Edda Marie; Seppey, Victor William Christophe; Tveit, Alexander Tøsdal; Svenning, Mette Marianne (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-08)
      Methane oxidizing bacteria (methanotrophs) within the genus <i>Methylobacter</i> constitute the biological filter for methane (CH<sub>4</sub>) in many Arctic soils. Multiple <i>Methylobacter</i> strains have been identified in these environments but we seldom know the ecological significance of the different strains. High-Arctic peatlands in Svalbard are heavily influenced by herbivory, leading to ...
    • Methyl 5-nitro-2-(phenylamino)pyridine-4-carboxylate 

      Hansen, Lars Kr; Tjosas, F; Tjosås, Freddy; Fiksdahl, A (Journal article; Tidsskriftartikkel; Peer reviewed, 2006)
    • The Methylococcus capsulatus (Bath) secreted protein, MopE*, binds both reduced and oxidized copper. 

      Ve, Thomas; Mathisen, Karina; Helland, Ronny; Karlsen, Odd Andre; Fjellbirkeland, Anne; Røhr, Åsmund Kjendseth; Andersson, K. Kristoffer; Pedersen, Rolf B.; Lillehaug, Johan R.; Jensen, Harald B (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Under copper limiting growth conditions the methanotrophic bacterium Methylococcus capsulatus (Bath) secrets essentially only one protein, MopE*, to the medium. MopE* is a copper-binding protein whose structure has been determined by X-ray crystallography. The structure of MopE* revealed a unique high affinity copper binding site consisting of two histidine imidazoles and one kynurenine, the latter ...
    • Microwave‐Assisted Synthesis of Heterocycles from Aryldiazoacetates 

      Kristoffersen, Tone; Elumalai, Vijayaragavan; Starck, Eliot; Cousin, Étienne; Hansen, Stephanie Ramona; Hansen, Jørn H (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-17)
      Herein, we describe a rapid microwave-assisted, metal-free synthesis of substituted quinoxalinones and quinoxalines using the carbene-mediated reaction between aryldiazo esters and 1,2-diamines. The reaction can encompass a range of substituents and structural variations to afford quinoxalin-2-ones in 14–80 % yield and corresponding quinoxalines in good to excellent yields upon oxidation (67–96 %). ...
    • 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 ...
    • MiMiC: Multiscale Modeling in Computational Chemistry 

      Bolnykh, Viacheslav; Olsen, Jógvan Magnus Haugaard; Meloni, Simone; Bircher, Martin P; Ippoliti, Emiliano; Carloni, Paolo; Rothlisberger, Ursula (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-20)
      Hybrid quantum mechanics/molecular mechanics (QM/MM) approaches are commonly used methods for investigating a plethora of chemical, biochemical, and biophysical processes that require explicit treatment of the electronic degrees of freedom when the system is too big to be entirely treated by QM methods alone (Warshel and Levitt, 1976; Senn and Thiel, 2009; Adhireksan et al., 2014; Campomanes et al., ...
    • miRNAs Predicted to Regulate Host Anti-viral Gene Pathways in IPNV-Challenged Atlantic Salmon Fry Are Affected by Viral Load, and Associated With the Major IPN Resistance QTL Genotypes in Late Infection 

      Woldemariam, Nardos Tesfaye; Agafonov, Oleg; Sindre, Hilde; Høyheim, Bjørn; Houston, Ross D.; Robledo, Diego; Bron, James E.; Andreassen, Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-11)
      Infectious pancreatic necrosis virus (IPNV) infection has been a major problem in salmonid aquaculture. Marker-assisted selection of individuals with resistant genotype at the major IPN quantitative trait locus (IPN-QTL) has significantly reduced mortality in recent years. We have identified host miRNAs that respond to IPNV challenge in salmon fry that were either homozygous resistant (RR) or ...
    • Mobile group I introns at nuclear rDNA position L2066 harbor sense and antisense homing endonuclease genes intervened by spliceosomal introns 

      Lian, Kjersti; Furulund, Betty Martine Normann; Tveita, Anders Aune; Haugen, Peik; Johansen, Steinar Daae (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-08)
      Background: Mobile group I introns encode homing endonucleases that confer intron mobility initiated by a double-strand break in the intron-lacking allele at the site of insertion. Nuclear ribosomal DNA of some fungi and protists contain mobile group I introns harboring His-Cys homing endonuclease genes (HEGs). An intriguing question is how protein-coding genes embedded in nuclear ribosomal DNA ...