Now showing items 121-140 of 253

    • How accurate is DFT for iridium-mediated chemistry? 

      Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-27)
      Iridium chemistry is versatile and widespread, with superior performance for reaction types such as enantioselective hydrogenation and C−H activation. In order to gain insight into the mechanistic details of such systems, density functional theory (DFT) studies are often employed. But how accurate is DFT for modeling iridium-mediated transformations in solution? We have evaluated how well DFT ...
    • How does relativity affect magnetically induced currents? 

      Berger, Raphael Johann Friedrich; Repisky, Michal; Komorovsky, Stanislav (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-23)
      Magnetically induced probability currents in molecules are studied in relativistic theory. Spin–orbit coupling (SOC) enhances the curvature and gives rise to a previously unobserved current cusp in AuH or small bulge-like distortions in HgH2 at the proton positions. The origin of this curvature is magnetically induced spin-density arising from SOC in the relativistic description.
    • A Hybrid of Bacterial Foraging and Differential Evolution -based Distance of Sequences 

      Muhammad Fuad, Muhammad Marwan (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • The immediate global responses of Aliivibrio salmonicida to iron limitations 

      Thode, Sunniva Katharina; Kahlke, Tim; Robertsen, Espen Mikal; Hansen, Hilde; Haugen, Peik (Journal article; Tidsskriftartikkel, 2015-02-04)
      <i>Background</i>: Iron is an essential micronutrient for all living organisms, and virulence and sequestration of iron in pathogenic bacteria are believed to be correlated. As a defence mechanism, potential hosts therefore keep the level of free iron inside the body to a minimum. In general, iron metabolism is well studied for some bacteria (mostly human or animal pathogens). However, this area ...
    • Impacts of climate and emission changes on nitrogen deposition in Europe: A multi-model study 

      Simpson, David; Andersson, Camilla; Christensen, Jesper Heile; Engardt, Magnuz; Geels, Camilla; Nyiri, Agnes; Posch, Maximilian; Soares, Joana B.P.; Sofiev, Mikhail; Wind, Peter; Langner, Joakim (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • 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 ...
    • Indirect NMR spin-spin coupling constants in diatomic alkali halides 

      Jaszuński, Michał; Antušek, Andrej; Demissie, Taye Beyene; Komorovsky, Stanislav; Repisky, Michal; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-28)
      We report the Nuclear Magnetic Resonance (NMR) spin–spin coupling constants for diatomic alkali halides MX, where M = Li, Na, K, Rb, or Cs and X = F, Cl, Br, or I. The coupling constants are determined by supplementing the non-relativistic coupled-cluster singles-and-doubles (CCSD) values with relativistic corrections evaluated at the four-component density-functional theory (DFT) level. These ...
    • The influence of sediment properties and experimental variables on the efficiency of electrodialytic removal of metals from sediment 

      Pedersen, Kristine Bondo; Lejon, Tore; Jensen, Pernille E.; Ottosen, Lisbeth M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-16)
      <p>Chemometrics was used to determine the influence of sediment properties and experimental settings for the electrodialytic removal (EDR) of Cu, Pb and Zn from six harbour sediments from Greenland and Norway. A Projection onto latent structures (PLS) model revealed that the most important sediment properties for achieving acidification (lag-phase, pH > 4), necessary for desorbing and mobilising ...
    • Inhibition of aurora kinase B is important for biologic activity of the dual inhibitors of BCR-ABL and aurora kinases R763/ AS703569 and PHA-739358 in BCR-ABL transformed cells 

      Illert, Anna L; Seitz, Anna K.; Rummelt, Christoph; Kreutmair, Stefanie; Engh, Richard Alan; Goodstal, Samantha; Peschel, Christian; Duyster, Justus; von Bubnoff, Nikolas (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • 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 ...
    • Insight into the fluorescence quenching of Trp214 at HSA by the Dimetridazole ligand from simulation 

      Pomogaev, Valdimir A; Ramazanov, Ruslan R; Ruud, Kenneth; Artyukhov, Victor Ya (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-08-24)
      Spectroscopy is an important tool for detecting drug binding to amino acid sequences. One such important spectroscopic process is the fluorescence quenching due to charge transfer (CT) processes between a drug molecule and the chromophore center of Human Serum Albumin (HSA). We present a theoretical investigation of the CT occurring upon electronic excitation when a dimetridazole (Dmz) molecule ...
    • Intermolecular charge transfer enhances two-photon absorption in yellow fluorescent protein 

      Beerepoot, Maarten T. P.; Friese, Daniel Henrik; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      We present a quantum chemical study of the two-photon absorption (TPA) properties of yellow fluorescent protein (YFP), a mutant of the extensively studied green fluorescent protein. The aromatic chromophore of YFP has a π-stacking interaction with the aromatic ring of a tyrosine residue (Tyr203) in a parallel-displaced structure with a distance of about 3.4 Å. We study the TPA spectrum of the ...
    • Interplay of twist angle and solvents with two-photon optical channel interference in aryl-substituted BODIPY dyes 

      Alam, MD Mehboob; Misra, Ramprasad; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-11)
      Channel interference plays a crucial role in understanding the physics behind multiphoton absorption processes. In this work, we study the role of channel interference and solvent effects on the two-photon absorption in aryl-substituted boron dipyrromethene (BODIPY) dyes, a class of intramolecular charge-transfer (ICT) molecules. For this purpose, we consider fourteen dyes of this class with various ...
    • Interpreting the paramagnetic NMR spectra of potential Ru(III) metallodrugs: synergy between experiment and relativistic DFT calculations 

      Novotný, Jan; Sojka, Martin; Komorovsky, Stanislav; Nečas, Marek; Marek, Radek (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-06-16)
      Ruthenium-based compounds are potential candidates for use as anticancer metallodrugs. The central ruthenium atom can be in the oxidation state +2 (e.g., RAPTA, RAED) or +3 (e.g., NAMI, KP). In this study we focus on paramagnetic NAMI analogs of a general structure [4-R-pyH]+ <i>trans</i>-[Ru<sup>III</sup>Cl<sub>4</sub>(DMSO)(4-R-py)]<sup>−</sup>, where 4-R-py stands for a 4-substituted pyridine. ...
    • Investigating the role of residues W228 and Y233 in the structure and activity of the GIM-1 metallo-beta-lactamase. 

      Skagseth, Susann; Carlsen, Trine Josefine Olsen; Bjerga, Gro Elin Kjæreng; Spencer, James; Samuelsen, Ørjan; Leiros, Hanna-Kirsti S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12-07)
      Metallo--lactamases (MBLs) hydrolyze virtually all -lactam antibiotics, including penicillins, cephalosporins, and carbapenems. The worldwide emergence of antibiotic-resistant bacteria harboring MBLs poses an increasing clinical threat. The MBL German imipenemase-1 (GIM-1) possesses an active site that is narrower and more hydrophobic than the active sites of other MBLs. The GIM-1 active-site ...
    • Iridium-PHOX-mediated alkene hydrogenation: Isomerisation influences the stereochemical outcome 

      Hopmann, Kathrin Helen; Frediani, Luca; Bayer, Annette (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-05-27)
      Recent experimental studies of iridium-phosphinooxazoline-mediated alkene hydrogenation indicated two dihydride species as resting states, with the minor isomer assumed to give rise to the major product enantiomer [Gruber and Pfaltz, Angew. Chem. Int. Ed. 2014, 53, 1896]. B3LYP-D2 calculations confirm the two dihydride intermediates as resting states but show that these species do not give rise to ...
    • Iron/Brønsted Acid Catalyzed Asymmetric Hydrogenation: Mechanism and Selectivity-Determining Interactions 

      Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-06-03)
      Hydrogenation catalysts involving abundant base metals such as cobalt or iron are promising alternatives to precious metal systems. Despite rapid progress in this field, base metal catalysts do not yet achieve the activity and selectivity levels of their precious metal counterparts. Rational improvement of base metal complexes is facilitated by detailed knowledge about their mechanisms and ...
    • Iron‐Catalyzed Carbenoid Transfer Reactions of Vinyl Sulfoxonium Ylides: An Experimental and Computational Study 

      Vaitla, Janakiram; Bayer, Annette; Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-15)
      A method for the generation of unprecedented vinyl carbenoids from sulfoxonium ylides has been developed and applied in the synthesis of a diverse array of heterocycles such as indolizines, pyrroles, 3‐pyrrolin‐2‐ones, and furans. The reactions proceed by FeBr<sub>2</sub> catalysis under mild reaction conditions with a broad substrate scope. A reaction pathway involving iron carbenoids is proposed ...
    • Isocorroles as Homoaromatic NIR-Absorbing Chromophores: A First Quantum Chemical Study 

      Foroutan-Nejad, Cina; Larsen, Simon; Conradie, Jeanet; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-10)
      Density functional theory calculations of magnetically induced current densities have revealed high diatropic ring currents in unsubstituted isocorrole consistent with homoaromatic character. An examination of the Kohn-Sham molecular orbitals showed clear evidence of homoconjugative interactions in four occupied π-type molecular orbitals as well as in the LUMO. Remarkably, substituents at the saturated ...
    • Isolation and Characterization of Anti-Adenoviral Secondary Metabolites from Marine Actinobacteria 

      Strand, Mårten; Carlsson, Marcus; Uvell, Hanna; Islam, Koushikul; Edlund, Karin; Cullman, Inger; Altermark, Bjørn; Mei, Ya-Fang; Elofsson, Mikael; Willassen, Nils Peder; Wadell, Göran; Almqvist, Fredrik (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)