Viser treff 81-100 av 551

    • Recolonization and recovery of an Arctic benthic community subject to mine-tailings deposits 

      Trannum, Hilde C; Pedersen, Kristine B.; Renaud, Paul E; Christensen, Guttorm N.; Evenset, Anita (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-22)
      Deposition of large volumes of mine tailings takes place in several Norwegian fjords, but the impacts on marine ecosystems have received relatively little scientific attention. At a 40 + − year old tailing deposition area for a copper mine in the Arctic fjord Repparfjorden, we investigated both short-term colonization of mine tailingscontaminated sediments through a field experiment, and the present ...
    • Visible light-exposed lignin facilitates cellulose solubilization by lytic polysaccharide monooxygenases 

      Kommedal, Eirik; Angeltveit, Camilla Fløien; Klau, Leesa Jane; Ayuso-Fernandez, Ivan; Arstad, Bjørnar; Antonsen, Simen; Stenstrøm, Yngve; Ekeberg, Dag; Gírio, Francisco; Carvalheiro, Florbela; Horn, Svein Jarle; Aachmann, Finn Lillelund; Eijsink, Vincent (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-24)
      Lytic polysaccharide monooxygenases (LPMOs) catalyze oxidative cleavage of crystalline polysaccharides such as cellulose and are crucial for the conversion of plant biomass in Nature and in industrial applications. Sunlight promotes microbial conversion of plant litter; this effect has been attributed to photochemical degradation of lignin, a major redox-active component of secondary plant cell walls ...
    • Can the absolute configuration of cyclic peptides be determined with vibrational circular dichroism? 

      Eikås, Karolina Di Remigio; Monika, Krupová; Kristoffersen, Tone; Beerepoot, Maarten; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-16)
      Cyclic peptides show a wide range of biological activities, among others as antibacterial agents. These peptides are often large and flexible with multiple chiral centers. The determination of the stereochemistry of molecules with multiple chiral centers is a challenging and important task in drug development. Chiroptical spectroscopies such as vibrational circular dichroism (VCD) can ...
    • N-Heteroaryl Carbamates from Carbon Dioxide via Chemoselective Superbase−Catalysis: Substrate Scope and Mechanistic Investigation 

      Mannisto, Jere K.; Pavlovic, Ljiljana; Heikkinen, Johannes; Tiainen, Tony; Sahari, Aleksi; Maier, Norbert; Rissanen, Kari; Nieger, Martin; Hopmann, Kathrin Helen; Repo, Timo (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-16)
      We report a mild superbase-catalyzed and nitrogen-selective carboxylation of N-heteroaryls, with subsequent alkylation enabling the synthesis of drug-like O-alkyl carbamates in good yields (av. 86%). Our findings suggest a partial revision of the current mechanistic understanding as superbases upon mixing with indoles and azoles generally form uncharged hydrogen-bonded complexes and not ionic salts ...
    • Bipartite Genomes in Enterobacterales: Independent Origins of Chromids, Elevated Openness and Donors of Horizontally Transferred Genes 

      Sonnenberg, Cecilie Bækkedal; Haugen, Peik (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-21)
      Multipartite bacteria have one chromosome and one or more chromid. Chromids are believed to have properties that enhance genomic flexibility, making them a favored integration site for new genes. However, the mechanism by which chromosomes and chromids jointly contribute to this flexibility is not clear. To shed light on this, we analyzed the openness of chromosomes and chromids of the two bacteria, ...
    • Liposome Formulations for the Strategic Delivery of PARP1 Inhibitors: Development and Optimization 

      Conceição, Carlota J. F.; Moe, Elin; Ribeiro, Paulo A.; Raposo, Maria (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-11)
      first_pagesettingsOrder Article Reprints Open AccessArticle Liposome Formulations for the Strategic Delivery of PARP1 Inhibitors: Development and Optimization by Carlota J. F. Conceição 1,2ORCID,Elin Moe 3,4,Paulo A. Ribeiro 2ORCID andMaria Raposo 2,*ORCID 1 CEFITEC, Department of Physics, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal 2 Laboratory ...
    • Accurate Relativistic Real-Time Time-Dependent Density Functional Theory for Valence and Core Attosecond Transient Absorption Spectroscopy 

      Moitra, Torsha; Konecny, Lukas; Kadek, Marius; Rubio, Angel; Repisky, Michal (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-09)
      First principles theoretical modeling of out-of-equilibrium processes observed in attosecond pump–probe transient absorption spectroscopy (TAS) triggering pure electron dynamics remains a challenging task, especially for heavy elements and/or core excitations containing fingerprints of scalar and spin–orbit relativistic effects. To address this, we formulate a methodology for simulating TAS within ...
    • Transition-Metal Isocorroles as Singlet Oxygen Sensitizers 

      Larsen, Simon; Adewuyi, Joseph A.; Ung, Gaël; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-04)
      Building on a highly efficient synthesis of pyrrole-appended isocorroles, we have worked out conditions for manganese, palladium, and platinum insertion into free-base 5/10-(2-pyrrolyl)-5,10,15-tris(4-methylphenyl)isocorrole, H<sub>2</sub>[5/10-(2-py)- TpMePiC]. Platinum insertion proved exceedingly challenging but was finally accomplished with cis-Pt(PhCN)<sub>2</sub>Cl<sub>2</sub>. All the ...
    • Combination of adsorption/desorption and photocatalytic reduction processes for PFOA removal from water by using an aminated biosorbent and a UV/sulfite system 

      Ren, Zhongfei; Bergmann, Ulrich; Uwayezu, Jean Noel; Carabante, Ivan; Kumpiene, Jurate; Lejon, Tore; Leiviskä, Tiina (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-17)
      Per- and polyfluoroalkyl substances (PFAS) are stable organic chemicals, which have been used globally since the 1940s and have caused PFAS contamination around the world. This study explores perfluorooctanoic acid (PFOA) enrichment and destruction by a combined method of sorption/desorption and photocatalytic reduction. A novel biosorbent (PG-PB) was developed from raw pine bark by grafting amine ...
    • Theoretical Photoelectron Spectroscopy of Low-Valent Carbon Species: A ∼6 eV Range of Ionization Potentials among Carbenes, Ylides, and Carbodiphosphoranes 

      Ghosh, Abhik; Conradie, Jeanet (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-02)
      High-quality density functional theory calculations underscore a nearly 6 eV range for the ionization potentials (IPs) of neutral, low-valent carbon compounds, including carbenes, ylides, and zero-valent carbon compounds (carbones) such as carbodiphosphoranes (CDPs) and carbodicarbenes. Thus, adiabatic IPs as low as 5.5 ± 0.1 eV are predicted for CDPs, which are about 0.7–1.2 eV lower than those of ...
    • Band structures and Z2 invariants of two-dimensional transition metal dichalcogenide monolayers from fully relativistic Dirac-Kohn-Sham theory using Gaussian-type orbitals 

      Kadek, Marius; Wang, Baokai; Joosten, Marc; Chiu, Wei-Chi; Mairesse, Francois; Repisky, Michal; Ruud, Kenneth; Bansil, Arun (Journal article; Tidsskriftartikkel, 2023-06-02)
      Two-dimensional (2D) materials exhibit a wide range of remarkable phenomena, many of which owe their existence to the relativistic spin-orbit coupling (SOC) effects. To understand and predict properties of materials containing heavy elements, such as the transition-metal dichalcogenides (TMDs), relativistic effects must be taken into account in first-principles calculations. We present an all-electron ...
    • Goldilocks Dilemma: LPS Works Both as the Initial Target and a Barrier for the Antimicrobial Action of Cationic AMPs on E. coli 

      Jakubec, Martin; Rylandsholm, Fredrik G.; Rainsford, Philip; Silk, Mitchell; Bril'kov, Maxim; Kristoffersen, Tone; Juskewitz, Eric; Ericson, Johanna U; Svendsen, John Sigurd Mjøen (Journal article; Tidsskriftartikkel, 2023-07-20)
      Antimicrobial peptides (AMPs) are generally membrane-active compounds that physically disrupt bacterial membranes. Despite extensive research, the precise mode of action of AMPs is still a topic of great debate. This work demonstrates that the initial interaction between the Gram-negative E. coli and AMPs is driven by lipopolysaccharides (LPS) that act as kinetic barriers for the binding of AMPs to ...
    • Formative and Summative Automated Assessment with Multiple-Choice Question Banks 

      Beerepoot, Maarten (Journal article; Tidsskriftartikkel, 2023-07-18)
      Digital automated assessment is a valuable and time-efficient tool for educators to provide immediate and objective feedback to learners. Automated assessment, however, puts high demands on the quality of the questions, alignment with the intended learning outcomes, and the quality of the feedback provided to the learners. We here describe the development and use of a large number (N > 180) of ...
    • Conformational tuning improves the stability of spirocyclic nitroxides with long paramagnetic relaxation times 

      Sowinski, Mateusz; Gahlawat, Sahil; Lund, Bjarte Aarmo; Warnke, Anna-Luisa; Hopmann, Kathrin Helen; Lovett, Janet E.; Haugland, Marius Myreng (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-05)
      Nitroxides are widely used as probes and polarization transfer agents in spectroscopy and imaging. These applications require high stability towards reducing biological environments, as well as beneficial relaxation properties. While the latter is provided by spirocyclic groups on the nitroxide scaffold, such systems are not in themselves robust under reducing conditions. In this work, we introduce ...
    • Automatisk rettet eksamen i generell kjemi 

      Beerepoot, Maarten; Kosonen, Juho A. (Conference object; Konferansebidrag, 2023-03)
      En god avsluttende eksamen vurderer i hvilken grad intendert læringsutbytte har blitt oppnådd på en nøye, objektiv og reproduserbar måte. Det er imidlertid lite tilfredsstillende hvis en faglærer bruker mye tid på vurdering avlæring framfor vurdering forlæring underveis i semesteret. Derfor kan det være attraktivtå utforske muligheter med en digital automatisk rettet ...
    • Exact Two-Component TDDFT with Simple Two-Electron Picture-Change Corrections: X-ray Absorption Spectra Near L- and M-Edges of Four-Component Quality at Two-Component Cost 

      Konecny, Lukas; Komorovsky, Stanislav; Vicha, Jan; Ruud, Kenneth; Repisky, Michal (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-01)
      X-ray absorption spectroscopy (XAS) has gained popularity in recent years as it probes matter with high spatial and elemental sensitivities. However, the theoretical modeling of XAS is a challenging task since XAS spectra feature a fine structure due to scalar (SC) and spin–orbit (SO) relativistic effects, in particular near L and M absorption edges. While full four-component (4c) calculations of ...
    • 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 = ...
    • Development of potent cholinesterase inhibitors based on a marine pharmacophore 

      Elumalai, Vijayaragavan; Trobec, Tomaz; Grundner, Maja; Labriere, Christophe; Frangez, Robert; Sepcic, Kristina; Hansen, Jørn H; Svensson, Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-01)
      The management of neurological disorders such as dementia associated with Alzheimer's or Parkinson's disease includes the use of cholinesterase inhibitors. These compounds can slow down the progression of these diseases and can also be used in the treatment of glaucoma and myasthenia gravis. The majority of the cholinesterase inhibitors used in the clinic are derived from natural products and our ...
    • The Hyperporphyrin Concept: A Contemporary Perspective 

      Wamser, Carl C.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-30)
      The Gouterman four-orbital model conceptualizes porphyrin UV−visible spectra as dominated by four frontier molecular orbitals-two nearly degenerate HOMOs and two exactly degenerate LUMOS under D<sub>4h</sub> symmetry. These are well separated from all the other molecular orbitals, and normal spectra involve transitions among these MOs. Unusual spectra occur when additional orbitals appear in ...
    • Crystal Structure Evolution of Fluorine under High Pressure 

      Tantardini, Christian; Jalolov, Faridun N.; Kvashnin, Alexander G. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-01)
      Fluorinated compounds in the last decade were applied as photothermo-refractive glasses, high-stress lubricants, and pharmaceutical drugs due to their good mechanical properties and biocompatibility. Although fluorinated materials are largely employed, the possibility of predicting new structures was limited by the impossibility to use density functional theory (DFT) to describe interatomic ...