Viser treff 227-246 av 527

    • A Haar Wavelet-based Multi-resolution Representation Method of Time Series Data 

      Muhammad Fuad, Muhammad Marwan (Peer reviewed; Journal article; Tidsskriftartikkel, 2015-01-10)
      Similarity search of time series can be efficiently handled through a multi-resolution representation scheme which offers the possibility to use pre-computed distances that are calculated and stored at indexing time and then utilized at query time together with filters in the form of exclusion conditions which speed up the search. In this paper we introduce a new multi-resolution representation ...
    • Halogen Bonding: An Odd Chemistry? 

      Turunen, Lotta; Hansen, Jørn H; Erdélyi, Máté (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-03)
      Halogen bonding is a flourishing field of research, but has for long been little recognized. The same goes for its scientific hero, Odd Hassel, who laid the foundations for all current developments. The crystallographic observation of halogen−oxygen interatomic distances shorter than the sum of the van der Waals radii of the involved atoms, and the interpretation of this phenomenon as a charge-transfer ...
    • Harmonic Infrared and Raman Spectra in Molecular Environments Using the Polarizable Embedding Model 

      Dundas, Karen Oda Hjorth Minde; Beerepoot, Maarten T. P.; Ringholm, Magnus; Reine, Simen Sommerfelt; Bast, Radovan; List, Nanna Holmgaard; Kongsted, Jacob; Ruud, Kenneth; Olsen, Jógvan Magnus Haugaard (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-19)
      We present a fully analytic approach to calculate infrared (IR) and Raman spectra of molecules embedded in complex molecular environments modeled using the fragment-based polarizable embedding (PE) model. We provide the theory for the calculation of analytic second-order geometric derivatives of molecular energies and first-order geometric derivatives of electric dipole moments and dipole–dipole ...
    • Heavy-element–ligand covalence: ligand noninnocence in molybdenum and tungsten Viking-helmet Corroles 

      Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-07)
      Extensive DFT calculations with several exchange–correlation functionals indicate that molybdenum-dichlorido Viking helmet corroles are noninnocent with significant Mo<sup>IV</sup>-corrole<sup>˙2−</sup> character. The effect is mediated by a Mo(4d)-corrole(π) orbital interaction similar to that postulated for MnCl, FeCl and FeNO corroles. The effect also appears to operate in tungsten-dichlorido ...
    • Heterocyclic cellular lipid peroxidation inhibitors inspired by the marine antioxidant barettin 

      Labriere, Christophe; Andersen, Jeanette hammer; Albrigtsen, Marte; Hansen, Jørn H; Svenson, Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-22)
      The marine environment remains a rich source for the discovery and development of novel bioactive compounds. The present paper describes the design, synthesis and biological evaluation of a library of small molecule heterocyclic mimetics of the marine 2,5-diketopiperazine barettin which is a powerful natural antioxidant. By mainly focusing on the influence from the brominated indole and heterocyclic ...
    • The high catalytic rate of the cold-active Vibrio alkaline phosphatase requires a hydrogen bonding network involving a large interface loop 

      Hjörleifsson, Jens Guðmundur; Helland, Ronny; Magnusdottir, Manuela; Ásgeirsson, Bjarni (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-16)
      The role of surface loops in mediating communication through residue networks is still a relatively poorly understood part in the study of cold adaptation of enzymes, especially in terms of their quaternary interactions. Alkaline phosphatase (AP) from the psychrophilic marine bacterium <i>Vibrio splendidus</i> (VAP) is characterized by an analogous large surface loop in each monomer, referred to as ...
    • High natural PHA production from acetate in Cobetia sp. MC34 and Cobetia marina DSM 4741T and in silico analyses of the genus specific PhaC2 polymerase variant 

      Christensen, Mikkel; Jablonski, Piotr; Altermark, Bjørn; Irgum, Knut; Hansen, Hilde (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-20)
      Background: Several members of the bacterial Halomonadacea family are natural producers of polyhydroxyalkanoates (PHA), which are promising materials for use as biodegradable bioplastics. Type-strain species of Cobetia are designated PHA positive, and recent studies have demonstrated relatively high PHA production for a few strains within this genus. Industrially relevant PHA producers may therefore ...
    • High quality draft genome sequence of Streptomyces sp. strain AW19M42 isolated from a sea squirt in Northern Norway 

      Bjerga, Gro Elin Kjæreng; Hjerde, Erik; De Santi, Concetta; Williamson, Adele Kim; Smalås, Arne O.; Willassen, Nils Peder; Altermark, Bjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • A high-throughput, restriction-free cloning and screening strategy based on ccdB-gene replacement 

      Bjerga, Gro Elin Kjæreng; Lund, Bjarte Aarmo; Leiros, Hanna-Kirsti S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      Background In high-throughput demanding fields, such as biotechnology and structural biology, molecular cloning is an essential tool in obtaining high yields of recombinant protein. Here, we address recently developed restriction-free methods in cloning, and present a more cost-efficient protocol that has been optimized to improve both cloning and clone screening. Results In our case study, ...
    • 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.
    • How To Make Your Computational Paper Interesting and Have It Published 

      Hopmann, Kathrin Helen (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-11)
      In 1987, the late German chemist Peter Hofmann of the University of Heidelberg wrote: “We still have a long way to go until a computation will be able to compete with or to substitute a lab experiment... one could then conclude that theoretical work in this field—not being quantitatively reliable anyhow—is rather useless, except for the purpose of keeping theorists busy.” However, Hofmann continued: ...
    • A Hybrid of Bacterial Foraging and Differential Evolution -based Distance of Sequences 

      Muhammad Fuad, Muhammad Marwan (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • 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 ...
    • 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 ...
    • Identification and Cross-Characterisation of Artificial Promoters and 5′ Untranslated Regions in Vibrio natriegens 

      Tietze, Lisa; Hoff, Maria Wilhelmsen; Lale, Rahmi (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-27)
      Vibrio natriegens has recently gained attention as a novel fast-growing bacterium in synthetic biology applications. Currently, a limited set of genetic elements optimised for Escherichia coli are used in V. natriegens due to the lack of DNA parts characterised in this novel host. In this study, we report the identification and cross-characterisation of artificial promoters and 5′ untranslated ...
    • 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 ...
    • The impact of interplay between electronic and steric effects on the synthesis and the linear and non-linear optical properties of diketopyrrolopyrrole bearing benzofuran moieties 

      Purc, Anna; Koszarna, Beata; Iachina, Irina; Friese, Daniel Henrik; Tasior, Mariusz; Sobczyk, Krzysztof; Pedzinski, Tomasz; Brewer, Jonathan; Gryko, Daniel T (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-07)
      An in-depth investigation of the reaction of substituted salicylaldehydes with chloroacetonitrile led to the development of new conditions for the synthesis of 2-cyanobenzofurans. The crucial improvement lies in the use of phase-transfer catalysis in the second step, i.e., intramolecular aldol type condensation. In a two-step process, the reactants were transformed into a library of 3,6-bis(ben ...
    • 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)
    • Implementation of Relativistic Coupled Cluster Theory for Massively Parallel GPU-Accelerated Computing Architectures 

      Pototschnig, Johann V.; Papadopoulos, Anastasios; Lyakh, Dmitry I.; Repisky, Michal; Halbert, Loïc; Gomes, Andre Severo Pereira; Jensen, Hans Jørgen Aa.; Visscher, Lucas (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-09)
      In this paper, we report reimplementation of the core algorithms of relativistic coupled cluster theory aimed at modern heterogeneous high-performance computational infrastructures. The code is designed for parallel execution on many compute nodes with optional GPU coprocessing, accomplished via the new ExaTENSOR back end. The resulting ExaCorr module is primarily intended for calculations of molecules ...