Now showing items 21-40 of 551

    • Exploring the Frozen Armory: Antiphage Defense Systems in Cold-Adapted Bacteria with a Focus on CRISPR-Cas Systems 

      Sandsdalen, Greta Daae; Kumar, Animesh; Hjerde, Erik (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-20)
      Our understanding of the antiphage defense system arsenal in bacteria is rapidly expanding, but little is known about its occurrence in cold-adapted bacteria. In this study, we aim to shed light on the prevalence and distribution of antiphage defense systems in cold-adapted bacteria, with a focus on CRISPR-Cas systems. Using bioinformatics tools, Prokaryotic Antiviral Defense LOCator (PADLOC) and ...
    • Theoretical Photoelectron Spectroscopy of Quadruple-Bonded Dimolybdenum(II,II) and Ditungsten(II,II) Paddlewheel Complexes: Performance of Common Density Functional Theory Methods 

      Ghosh, Abhik; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-03)
      We have revisited the gas-phase photoelectron spectra of quadruplebonded dimolybdenum(II,II) and ditungsten(II,II) paddlewheel complexes with modern density functional theory methods and obtained valuable calibration of four well-known exchange−correlation functionals, namely, BP86, OLYP, B3LYP*, and B3LYP. All four functionals were found to perform comparably, with discrepancies between calculated ...
    • Inverse Photoemission Spectroscopy of Coinage Metal Corroles: Comparison with Solution-Phase Electrochemistry 

      Giovanelli, Luca; Ksari, Younal; Mrezguia, Hela; Salomon, Eric; Minissale, Marco; Alemayehu, Abraham; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-19)
      A combined direct and inverse photoemission study of coinage metal corroles suggests that the latter technique, in favorable cases, can provide some additional information relative to electrochemical measurements. Thus, whereas inverse photoemission spectroscopy (IPES) provides relative electron affinities for electron addition to different unoccupied orbitals, electrochemical reduction potentials ...
    • Rethinking gold(II) porphyrins: an inherent wave distortion 

      Ghosh, Abhik; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-23)
      Relativistic DFT (OLYP-D3/ZORA-STO-TZ2P) calculations predict low adiabatic ionization potentials for gold(II) porphyrins, from 4.60 eV for Au[TPP] (TPP = tetraphenylporphyrin) to 5.34 eV for Au[TPFPP] [TPFPP = tetrakis(pentafluorophenyl)porphyrin]. These values are over 1 eV lower than those calculated for analogous silver(II) porphyrins, reflecting much greater relativistic destabilization of ...
    • Hvem bør ha ansvar for kjemilab? 

      Walquist, Mari J.; Beerepoot, Maarten T. P. (Preprint; Manuskript, 2024-05-14)
      Mange ulike studieprogram har et innføringsemne i kjemi, ofte i første studieåret. Et slikt kjemiemne inkluderer vanligvis laboratorieundervisning, som er ressurskrevende å gjennomføre for et stort antall (flere hundre) studenter. Det er vanlig at instituttet som har ansvar for emnet også har ansvar for laboratorieundervisningen. Dermed får studentene på ulike studieprogram samme labøvelser av samme ...
    • DFT and electrochemical study on some iron(III) complexes with 2-hydroxybenzophenones 

      Chiyindiko, Emmie; Langner, Ernst H.G.; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-17)
      The synthesis, identification and electrochemical behaviour iron(III) complexes containing different 2-hydroxybenzophenone ligands are reported. The first reduction of the tris(2-hydroxybenzophenone)iron(III) complexes follow the same trend as that of the free, uncoordinated ligands and bis(2-hydroxybenzophenone)copper(II) complexes. The first reduction of the iron(III) complexes occur at a potential ...
    • Quantifying Intramolecular Basis Set Superposition Errors 

      Pitteloud, Quentin Grégoire; Wind, Peter; Jensen, Stig Rune; Frediani, Luca; Jensen, Frank (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-18)
      We show that medium-sized Gaussian basis sets lead to significant intramolecular basis set superposition errors at Hartree–Fock and density functional levels of theory, with artificial stabilization of compact over extended conformations for a 186 atom deca-peptide. Errors of ∼80 and ∼10 kJ/mol are observed, with polarized double zeta and polarized triple zeta quality basis sets, respectively. Two ...
    • Efficient palladium-catalyzed electrocarboxylation enables late-stage carbon isotope labelling 

      Batista, Gabriel M. F.; Ebenbauer, Ruth; Day, Craig S.; Bergare, Jonas; Neumann, Karoline; Hopmann, Kathrin Helen; Elmore, Charles; Rosas-Hernandez, Alonso; Skrydstrup, Troels (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-22)
      Carbon isotope labelling of bioactive molecules is essential for accessing the pharmacokinetic and pharmacodynamic properties of new drug entities. Aryl carboxylic acids represent an important class of structural motifs ubiquitous in pharmaceutically active molecules and are ideal targets for the installation of a radioactive tag employing isotopically labelled CO<sub>2</sub>. However, direct isotope ...
    • Adsorption free energy of phenol onto coronene: Solvent and temperature effects 

      Malloum, Alhadji; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-11)
      Molecular modeling can considerably speed up the discovery of materials with high adsorption capacity for wastewater treatment. Despite considerable efforts in computational studies, the molecular modeling of adsorption processes has several limitations in reproducing experimental conditions. Handling the environmental effects (solvent effects) and the temperature effects are part of the important ...
    • Hydrogen bond networks of dimethylsulfoxide (DMSO) pentamer 

      Malloum, Alhadji; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-17)
      Understanding of clusters of dimethylsulfoxide (DMSO) is important in several applications in Chemistry. Despite its importance, very few studies of DMSO clusters, (DMSO)<i><sub>n</i></sub> , have been reported in comparison to systems such as water clusters or methanol clusters. In order to provide further understanding of DMSO clusters, we investigated the structures and non-covalent interactions ...
    • Regiodivergent Synthesis of 11H-Indolo[3,2-c]quinolines and Neocryptolepine from a Common Starting Material 

      Håheim, Katja Stangeland; Lund, Bjarte Aarmo; Sydnes, Magne Olav (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-23)
      A large number of diversely functionalized analogs of the bioactive natural products neocryptolepine and isocryptolepine have been prepared from a series of 3-bromoquinoline derivatives. The neocryptolepines were obtained by a Pd<sup>0</sup>-catalyzed C−C bond coupling followed by C−N bond formation in yields up to 80 %, whereas the indoloquinolines were prepared by a Suzuki-Miyaura cross-coupling ...
    • Photophysics of uracil: an explicit time-dependent generating function-based method combining both nonadiabatic and spin-orbit coupling effects 

      Karak, Pijush; Moitra, Torsha; Ruud, Kenneth; Chakrabarti, Swapan (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-14)
      We present a composite framework for calculating the rates of non-radiative deactivation processes, namely internal conversion (IC) and intersystem crossing (ISC), on an equal footing by explicitly computing the non-adiabatic coupling (NAC) and spin–orbit coupling (SOC) constants, respectively. The stationary-state approach uses a time-dependent generating function based on Fermi's golden rule. We ...
    • D3.3 (M18) - Report on curation in core ELIXIR registries (an ELIXIR Norway ELIXIR3 deliverable) 

      Bösl, Korbinian Michael; Fatima, Nazeefa; Gundersen, Sveinung; Klemetsen, Terje; Petters, Sebastian; Åberg, Espen (Research report; Forskningsrapport, 2023-10-01)
      This report serves as an update on the progress of WP3 Task 3.4 in ELIXIR3, in support of curation efforts on content in repositories of metadata, datasets, tools, training, workflows, and other resources, in line with the ELIXIR Platforms. The report documents progress made, methods used, and plans for the near future as of month 18 of a 48-month timeline. ELIXIR Norway extends support to numerous ...
    • Biological Evaluations, NMR Analyses, Molecular Modeling Studies, and Overview of the Synthesis of the Marine Natural Product (−)-Mucosin 

      Nolsøe, Jens Mortansson Jelstrup; Underhaug, Jarl; Sørskår, Åshild Moi; Antonsen, Simen; Malterud, Karl Egil; Gani, Osman; Fan, Qiong; Hjorth, Marit; Sæther, Thomas; Hansen, Trond Vidar; H. Stenstrøm, Yngve (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-24)
      Natural products obtained from marine organisms continue to be a rich source of novel structural architecture and of importance in drug discovery, medicine, and health. However, the success of such endeavors depends on the exact structural elucidation and access to sufficient material, often by stereoselective total synthesis, of the isolated natural product of interest. (−)-Mucosin (1), a fatty ...
    • Preventing E. coli Biofilm Formation with Antimicrobial Peptide-Functionalized Surface Coatings: Recognizing the Dependence on the Bacterial Binding Mode Using Live-Cell Microscopy 

      Hansson, Adam; Karlsen, Eskil André; Stensen, Wenche Gunvor B; Svendsen, John Sigurd Mjøen; Berglin, Mattias; Lundgren, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-31)
      Antimicrobial peptides (AMPs) can kill bacteria by destabilizing their membranes, yet translating these molecules’ properties into a covalently attached antibacterial coating is challenging. Rational design efforts are obstructed by the fact that standard microbiology methods are ill-designed for the evaluation of coatings, disclosing few details about why grafted AMPs function or do not ...
    • Quantitative at-line monitoring of enzymatic hydrolysis using benchtop diffusion nuclear magnetic resonance spectroscopy 

      McCarney, Evan R.; Kristoffersen, Kenneth Aase; Anderssen, Kathryn Elizabeth (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-18)
      Benchtop diffusion nuclear magnetic resonance (NMR) spectroscopy was used to perform quantitative monitoring of enzymatic hydrolysis. The study aimed to test the feasibility of the technology to characterize enzymatic hydrolysis processes in real time. Diffusion ordered spectroscopy (DOSY) was used to measure the signal intensity and apparent self-diffusion constant of solubilized protein in ...
    • 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 ...
    • Preparation of a Compound with a SiII−SiIV−SiII Bonding Arrangement 

      Kushvaha, Saroj Kumar; Kallenbach, Paula; Gorantla, Sai Manoj N. V. T.; Herbst-Irmer, Regine; Stalke, Dietmar; Roesky, Herbert W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-07)
      Herein, we report the synthesis of a rare bis-silylene, 1, in which two Si<sup>II</sup>atoms are bridged by a Si<sup>IV</sup> atom. Compound 1 contains an unusual Si<sup>II</sup> SiI<sup>V</sup> Si<sup>II</sup> bonding arrangement with Si<sup>II</sup> Si<sup>IV</sup> bond distances of 2.4212(8) and 2.4157(7) Å. Treatment of 1 with Fe(CO)<sub>5</sub> afforded a dinuclear Fe<sup>0</sup>S complex 2 ...
    • From Diaminosilylenes to Silapyramidanes: Making Sense of the Stability of Divalent Silicon Compounds 

      Torstensen, Kristian; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-07)
      Since the discovery of decamethylsilicocene over three decades ago, chemists have successfully isolated a variety of divalent silicon compounds by orchestrating steric and electronic effects to their advantage. Two broad strategies of electronic stabilization appear to have been widely deployed, namely, π-conjugation as in diaminosilylenes and π-complexation as in decamethylsilicocene and ...
    • Label-free measurement of antimicrobial peptide interactions with lipid vesicles and nanodiscs using microscale thermophoresis 

      Rainsford, Philip Ben; Rylandsholm, Fredrik G.; Jakubec, Martin; Silk, Mitchell; Juskewitz, Eric; Ericson, Johanna Ulrica; Svendsen, John Sigurd Mjøen; Engh, Richard Alan; Isaksson, Johan Mattias (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-03)
      One strategy to combat antimicrobial resistance is the discovery of new classes of antibiotics. Most antibiotics will at some point interact with the bacterial membrane to either interfere with its integrity or to cross it. Reliable and efficient tools for determining the dissociation constant for membrane binding (K<sub><i>D</sub></i>) and the partitioning coefficient between the aqueous- and ...