Now showing items 166-185 of 247

    • On the Application of Bio-Inspired Optimization Algorithms to Fuzzy C-Means Clustering of Time Series 

      Muhammad Fuad, Muhammad Marwan (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      Fuzzy c-means clustering (FCM) is a clustering method which is based on the partial membership concept. As with the other clustering methods, FCM applies a distance to cluster the data. While the Euclidean distance is widely-used to perform the clustering task, other distances have been suggested in the literature. In this paper we study the use of a weighted combination of metrics in FCM clustering ...
    • One electron changes the entire story: NMR versus pNMR 

      Demissie, Taye Beyene (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-28)
      <sup>11</sup>B NMR chemical shifts of structurally similar diamagnetic and paramagnetic molecules are obtained using four-component relativistic DFT calculations. The calculated chemical shifts of the diamagnetic molecules are compared with those of the paramagnetic molecules to get an insight on the influence of the unpaired electron on the <sup>11</sup>B chemical shifts.
    • One-Pot Synthesis of a bis-Pocket Corrole through a 14-fold Bromination Reaction. 

      Norheim, Hans-Kristian; Schneider, Christian; Gagnon, Kevin J.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-14)
      A one-pot protocol, effecting 14-fold bromination with elemental bromine, has afforded copper β-octabromo-meso-tris (2,6-dibromo-3,5-dimethoxyphenyl) corrole, a new bis-pocket metallocorrole. The Cu complex underwent smooth demetalation under reductive conditions, affording the free corrole ligand, which in turn could be readily complexed to MnIII and AuIII. A single-crystal X-ray structure was ...
    • One-Step or Two-Step Optimization and the Overfitting Phenomenon:A Case Study on Time Series Classification 

      Muhammad Fuad, Muhammad Marwan (Peer reviewed; Conference object; Konferansebidrag, 2014)
      For the last few decades, optimization has been developing at a fast rate. Bio-inspired optimization algorithms are metaheuristics inspired by nature. These algorithms have been applied to solve different problems in engineering, economics, and other domains. Bio-inspired algorithms have also been applied in different branches of information technology such as networking and software engineering. ...
    • One‐Pot Synthesis of a bis‐Pocket Corrole through a 14‐fold Bromination Reaction 

      Norheim, Hans-Kristian; Schneider, Christian; Gagnon, Kevin J.; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-14)
      A one-pot protocol, effecting 14-fold bromination with elemental bromine, has afforded copper beta-octabromo-meso-tris(2,6-dibromo-3,5-dimethoxyphenyl)corrole, a new bis-pocket metallocorrole. The Cu complex underwent smooth demetalation under reductive conditions, affording the free corrole ligand, which in turn could be readily complexed to Mn<sup>III</sup> and Au<sup>III</sup>.A single-crystal ...
    • Open-ended formulation of self-consistent field response theory with the polarizable continuum model for solvation 

      Di Remigio, Roberto; Beerepoot, Maarten; Cornaton, Yann; Ringholm, Magnus; Steindal, Arnfinn Hykkerud; Ruud, Kenneth; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-15)
      The study of high-order absorption properties of molecules is a field of growing importance. Quantumchemical studies can help design chromophores with desirable characteristics. Given that most experiments are performed in solution, it is important to devise a cost-effective strategy to include solvation effects in quantum-chemical studies of these properties. We here present an open-ended ...
    • Open-ended recursive approach for the calculation of multiphoton absorption matrix elements 

      Friese, Daniel Henrik; Beerepoot, Maarten T. P.; Ringholm, Magnus; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-02-11)
      We present an implementation of single residues for response functions to arbitrary order using a recursive approach. Explicit expressions in terms of density-matrix-based response theory for the single residues of the linear, quadratic, cubic, and quartic response functions are also presented. These residues correspond to one-, two-, three- and four-photon transition matrix elements. The newly ...
    • Open-Ended Recursive Calculation of Single Residues of Response Functions for Perturbation-Dependent Basis Sets 

      Friese, Daniel Henrik; Ringholm, Magnus; Gao, Bin; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-09-09)
      We present theory, implementation, and applications of a recursive scheme for the calculation of single residues of response functions that can treat perturbations that affect the basis set. This scheme enables the calculation of nonlinear light absorption properties to arbitrary order for other perturbations than an electric field. We apply this scheme for the first treatment of two-photon circular ...
    • Open-ended response theory with polarizable embedding: multiphoton absorption in biomolecular systems 

      Steindal, Arnfinn Hykkerud; Beerepoot, Maarten; Ringholm, Magnus; List, Nanna Holmgaard; Ruud, Kenneth; Kongsted, Jacob; Olsen, Jógvan Magnus Haugaard (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-19)
      We present the theory and implementation of an open-ended framework for electric response properties at the level of Hartree–Fock and Kohn–Sham density functional theory that includes effects from the molecular environment modeled by the polarizable embedding (PE) model. With this new state-of-the-art multiscale functionality, electric response properties to any order can be calculated for molecules ...
    • The optical activity of beta, gamma-enones in ground and excited states using circular dichroism and circularly polarized luminescence 

      Pecul, Magdalena; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2011)
      The circularly polarized luminescence (CPL) and electronic circular dichroism (CD) spectroscopic parameters corresponding to the n ← π* and n → π* transitions, respectively, have been calculated for selected β,γ-enones using density functional theory. For the smallest β,γ-enone, (1R,4R)-bicyclo[2.2.1]hept-5-en-2-one (norbornenone), coupled-cluster calculations have also been carried out. The ...
    • An optimised method for electrodialytic removal of heavy metals from harbour sediments 

      Pedersen, Kristine Bondo; Jensen, Pernille E.; Ottosen, Lisbeth M.; Lejon, Tore (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-10)
      A 2-compartment electrodialytic cell set-up for treatment of solid materials has in many respects proven superior to other types of cells in removing heavy metals from sediments. Most notably, remediation times were shorter, energy consumption was lower and higher removal efficiencies were observed. By employing multivariate modelling and investigating additional experimental variables, the ...
    • The origin dependence of the material constants: the permittivity and the inverse permeability 

      Anelli, Marco; Jonsson, Dan Johan; Fliegl, Heike; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-05-26)
      New derivations of origin-independent expressions for the electric permittivity are presented, starting either from the response function of the current density that defines the absorption coefficient, or from the off-resonance single-photon scattering amplitude that leads to the Kramers–Heisenberg dispersion formula. The resulting expression for the permittivity is compared with earlier work ...
    • Origin of Dual-Peak Phosphorescence and Ultralong Lifetime of 4,6-Diethoxy-2-carbazolyl-1,3,5-triazine 

      Paul, Lopa; Chakrabarti, Swapan; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-02)
      Recently, ultralong phosphorescence lifetime has been observed in 4,6-diethoxy-2-carbazolyl-1,3,5-triazine, and H-aggregation induced stabilization of the T1 state was suggested as its source. The response theory calculations demonstrate that the Davydov stabilization of the T1 state of the dimer is marginal with respect to the monomer and the corresponding transition moments are virtually the same. ...
    • OXA-48-Mediated Ceftazidime-Avibactam Resistance Is Associated with Evolutionary Trade-Offs 

      Frøhlich, Christopher; Sørum, Vidar; Thomassen, Ane Molden; Johnsen, Pål Jarle; Samuelsen, Ørjan (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-27)
      Infections due to carbapenemase-producing Gram-negative pathogens are associated with limited treatment options and consequently lead to increased mortality and morbidity. In response, combinations of existing β-lactams and novel β-lactamase inhibitors, such as ceftazidime-avibactam (CAZ-AVI), have been developed as alternative treatment options. To understand the development of resistance and ...
    • Palladium(0)-Catalyzed Cross-Couplings of 2-Bromophosphinine 

      Kostenko, Nataliya; Eriksson, Cecilia; Engqvist, Magnus; Villa Gonzalez, Susana; Bayer, Annette (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-05-21)
      A new Negishi-type cross-coupling of 2-bromophosphinine has been developed. The new method expands the scope of palladium-catalyzed couplings to monobromophosphinines, which have been considered as poor substrates so far. Moreover, aryl-, alkenyl-, and alkynylzinc bromides were found to be effective coupling partners.
    • Pan genome and CRISPR analyses of the bacterial fish pathogen Moritella viscosa 

      Karlsen, Christian; Hjerde, Erik; Klemetsen, Terje; Willassen, Nils Peder (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-04-20)
      Background: Winter-ulcer Moritella viscosa infections continue to be a significant burden in Atlantic salmon (Salmo salar L.) farming. M. viscosa comprises two main clusters that differ in genetic variation and phenotypes including virulence. Horizontal gene transfer through acquisition and loss of mobile genetic elements (MGEs) is a major driving force of bacterial diversification. To gain insight ...
    • Parameter-Free Extended Edit Distance 

      Muhammad Fuad, Muhammad Marwan (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
      The edit distance is the most famous distance to compute the similarity between two strings of characters. The main drawback of the edit distance is that it is based on local procedures which reflect only a local view of similarity. To remedy this problem we presented in a previous work the extended edit distance, which adds a global view of similarity between two strings. However, the extended edit ...
    • PCMSolver: an Open-Source Library for Solvation Modeling 

      Di Remigio, Roberto; Steindal, Arnfinn Hykkerud; Mozgawa, Krzysztof; Weijo, Ville; Cao, Hui; Frediani, Luca (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-25)
      PCMSolver is an open‐source library for continuum electrostatic solvation. It can be combined with any quantum chemistry code and requires a minimal interface with the host program, greatly reducing programming effort. As input, PCMSolver needs only the molecular geometry to generate the cavity and the expectation value of the molecular electrostatic potential on the cavity surface. It then returns ...
    • Perturbed atoms in molecules and solids:the PATMOS model 

      Røeggen, Inge; Gao, Bin (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      A new computational method for electronic-structure studies of molecules and solids is presented. The key element in the new model – denoted the perturbed atoms in molecules and solids model – is the concept of a perturbed atom in a complex. The basic approximation of the new model is unrestricted Hartree Fock (UHF). The UHF orbitals are localized by the Edmiston-Ruedenberg procedure. The perturbed ...
    • Platinum Corroles 

      Alemayehu, Abraham; Vazquez-Lima, Hugo; Beavers, Christine M.; Gagnon, Kevin J.; Bendix, Jesper; Ghosh, Abhik (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-06-09)
      Platinum has been inserted into corroles for the first time and three oxidized PtIV(corrole2)ArAr0 complexes have been structurally characterized. The Soret maxima of these complexes exhibit an unusually strong dependence on the meso-aryl substituents on the corrole, indicating aryl - corrole2 charge transfer character in these transitions.