Now showing items 541-560 of 601

    • Ab initio studies of two pyrimidine derivatives as possible photo-switch systems 

      Csehi, András; Woywod, Clemens Joachim; Halász, Gábor J.; Vibok, Agnes (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The six lowest lying electronic singlet states of 8-(pyrimidine-2-yl)quinolin-ol and 2-(4-nitropyrimidine-2- yl)ethenol have been studied theoretically using the complete active space self-consistent-field (CASSCF) and Møller-Plesset second-order perturbation theory (MP2) methods. Both molecules can be viewed as consisting of a frame and a crane component. As a possible mechanism for the excited-state ...
    • Effect of donor–acceptor orientation on solvent-dependent three-photon activity in through-space charge-transfer systems – case study of [2,2]-paracyclophane derivatives 

      Alam, MD Mehboob; Chattopadhyaya, Mausumi; Chakrabarti, Swapan; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      We study the effect of donor–acceptor orientation on solvent-dependent three-photon transition probabilities (δ3PA) of representative through-space charge-transfer (TSCT) systems, namely, doubly positively charged [2,2]-paracyclophane derivatives. Our cubic response calculations reveal that the value of δ3PA may be as high as 106 a.u., which can further be increased by a specific orientation of the ...
    • Analytic evaluation of the dipole Hessian matrix in coupled-cluster theory 

      Jagau, TC; Gauss, J; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The general theory required for the calculation of analytic third energy derivatives at the coupled-cluster level of theory is presented and connected to preceding special formulations for hyperpolarizabilities and polarizability gradients. Based on our theory, we have implemented a scheme for calculating the dipole Hessian matrix in a fully analytical manner within the coupled-cluster singles and ...
    • A Pre-initialization Stage of Population-Based Bio-inspired Metaheuristics for Handling Expensive Optimization Problems 

      Muhammad Fuad, Muhammad Marwan (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Metaheuristics are probabilistic optimization algorithms which are applicable to a wide range of optimization problems. Bio-inspired, also called nature-inspired, optimization algorithms are the most widely-known metaheuristics. The general scheme of bio-inspired algorithms consists in an initial stage of randomly generated solutions which evolve through search operations, for several generations, ...
    • When Optimization Is Just an Illusion 

      Muhammad Fuad, Muhammad Marwan (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Bio-inspired optimization algorithms have been successfully applied to solve many problems in engineering, science, and economics. In computer science bio-inspired optimization has different applications in different domains such as software engineering, networks, data mining, and many others. However, some applications may not be appropriate or even correct. In this paper we study this phenomenon ...
    • Structural and thermodynamic insight into phenylalanine hydroxylase from the human pathogen Legionella pneumophila 

      Leiros, Hanna-Kirsti S.; Flydal, Marte Innselset; Martinez, Aurora (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Phenylalanine hydroxylase from Legionella pneumophila (lpPAH) has a major functional role in the synthesis of the pigment pyomelanin, which is a potential virulence factor. We present here the crystal structure of lpPAH, which is a dimeric enzyme that shows high thermostability, with a midpoint denat- uration temperature of 79 ◦C, and low substrate affinity. The structure revealed a dimerization ...
    • Spin-rotation and NMR shielding constants in HCl 

      Jaszunski, Michal; Repisky, Michal; Demissie, Taye B.; Komorovsky, Stanislav; Malkin, Elena; Ruud, Kenneth; Garbacz, Piotr; Jackowski, Karol; Makulski, W (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The spin-rotation and nuclear magnetic shielding constants are analysed for both nuclei in the HCl molecule. Nonrelativistic ab initio calculations at the CCSD(T) level of approximation show that it is essential to include relativistic effects to obtain spin-rotation constants consistent with accurate experimental data. Our best estimates for the spin-rotation constants of 1H35Cl are CCl =−53.914 ...
    • Pyrazine excited states revisited using the extended multi-state complete active space second-order perturbation method 

      Shiozaki, Toru; Woywod, Clemens Joachim; Werner, Hans-Joachim (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      We demonstrate that the recently developed extended multi-state complete active space second-order perturbation theory (XMS-CASPT2) [Shiozaki et al., J. Chem. Phys., 2011, 135, 081106] provides qualitatively correct potential energy surfaces for low-lying excited singlet states of pyrazine, while the potential energy surfaces of the standard MS-CASPT2 methods are ill-behaved near the crossing ...
    • 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 ...
    • A really close look at molecules 

      Svenson, Johan (Journal article; Tidsskriftartikkel, 2013)
      With a “magnifying glass”, a highly sophisticated atomic force microscope (AFM) scientists have recently developed a technique that allows single molecule visualization with atomic resolution.
    • Identification, cloning and expressions of proteases from a cold adapted organism Aliivibrio salmonicida 

      Ather, Arjumand (Master thesis; Mastergradsoppgave, 2009-07-27)
      The work presented in this thesis provides an overview of molecular and structural biology projects and their related problems. The problems arises during these projects are common for most of the target proteins, with varying intensity of severity. The realization and identification of these problems and selection of their correct, best possible solution is an imperative step that might lead to ...
    • Reductions of barbituric acid based compounds 

      Kristoffersen, Stian (Master thesis; Mastergradsoppgave, 2013-05-15)
      Reductions of chalconoids with different para- substituents on the phenyl ring have been investigated in order to screen for kinase inhibitors with improved properties.
    • Synthesis of β-substituted β-aminoboronates 

      Thomassen, Ivar Kristian (Master thesis; Mastergradsoppgave, 2013-05)
      Recent work at the University of Tromsø has uncovered new α-substituted α- and β-aminoboron containing peptidomimetics that shows antimicrobial, antifungal and antitubercular activity in addition to kinase inhibition and promotion. As a continuation of this work a new approach for the synthesis of β-substituted β-aminoboronates has been developed. The approach involves the non-stereospecific ...
    • Biotech applications of protein kinase affinity interactions 

      Lund, Bjarte Aarmo (Master thesis; Mastergradsoppgave, 2013-05)
      Protein kinases provide one of the cell’s most important methods for signaling and control. 2% of the encoding genome consists of protein kinase genes, and from 10-50% of the proteins in the cell are phosphorylated at some point in the cell cycle. Malfunction of protein kinases is connected to several disease-conditions, most prominently cancer, Alzheimer’s and diabetes. Understanding the ...
    • Karakterisering av kommersielle omega-3 produkter og utvikling av en ny metode for separasjon av lipidklasser med fast-fase ekstraksjon 

      Ovesen, Marte Stokvik (Master thesis; Mastergradsoppgave, 2012-11-15)
      Kliniske studier viser at inntak av omega-3 fettsyrene EPA, DPA og DHA kan bidra til å forebygge hjerte- og karsykdommer, redusere inflammasjon, påvirke sentralnervesystemets funksjon positivt og bidra til en rekke andre helsegevinster. Som en konsekvens har markedet for kommersielle omega-3 produkter økt de siste tiårene. Det ble kjøpt inn 10 produkter til dette studiet. Produktene baserte seg på ...
    • A Synthetic Route to Quaternary Pyridinium Salt-Functionalized Silsesquioxanes 

      Kostenko, Nataliya; Gottfriedsen, Jochen; Hilfert, Liane; Edelmann, Frank T (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      A synthetic route to potentially biocidal silsesquioxanes functionalized by quaternary pyridinium functionalities has been developed. N-Alkylation reactions of the precursor compounds 4-(2-(trimethoxysilyl)ethyl)-pyridine (5) and 4-(2-trichloro-silylethyl)pyridine (6) with iodomethane, n-hexylbromide, and n-hexadecylbromide cleanly afforded the corresponding N-alkylpyridinium salts (7–10). The ...
    • Molecular Characterization of Cold Adaptation of Membrane Proteins in the Vibrionaceae Core-Genome 

      Kahlke, Tim; Thorvaldsen, Steinar (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Cold-adaptation strategies have been studied in multiple psychrophilic organisms, especially for psychrophilic enzymes. Decreased enzyme activity caused by low temperatures as well as a higher viscosity of the aqueous environment require certain adaptations to the metabolic machinery of the cell. In addition to this, low temperature has deleterious effects on the lipid bilayer of bacterial membranes ...
    • The EMEP MSC-W chemical transport model - technical description 

      Simpson, David; Benedictow, Anna; Berge, Halldis; Bergström, Robert; Emberson, Lisa D.; Fagerli, Hilde; Flechard, Chris R.; Hayman, Garry D.; Gauss, Michael; Jonson, Jan Eiof; Jenkin, Michael E.; Nyiri, Agnes; Richter, Cornelia; Semeena, Valiyavetil S.; Tsyro, Svetlana; Tuovinen, Juha Pekka; Valdebenito, Alvaro; Wind, Peter (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      The Meteorological Synthesizing Centre-West (MSC-W) of the European Monitoring and Evaluation Programme (EMEP) has been performing model calculations in support of the Convention on Long Range Transboundary Air Pollution (CLRTAP) for more than 30 years. The EMEP MSC-W chemical transport model is still one of the key tools within European air pollution policy assessments. Traditionally, the model ...
    • Lipopolysaccharide O-Antigen Prevents Phagocytosis of Vibrio anguillarum by Rainbow Trout (Oncorhynchus mykiss) Skin Epithelial Cells 

      Lindell, Kristoffer; Fahlgren, Anna; Hjerde, Erik; Willassen, Nils Peder; Fällman, Maria; Milton, Debra L (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Colonization of host tissues is a first step taken by many pathogens during the initial stages of infection. Despite the impact of bacterial disease on wild and farmed fish, only a few direct studies have characterized bacterial factors required for colonization of fish tissues. In this study, using live-cell and confocal microscopy, rainbow trout skin epithelial cells, the main structural component ...
    • A multi-model study of impacts of climate change on surface ozone in Europe 

      Langner, J.; Engardt, M.; Baklanov, A.; Christensen, J. H.; Gauss, Michael; Geels, Camila; Hedegaard, G.B.; Nuterman, R.; Simpson, D.; Soares, J; Sofiev, M; Wind, Peter; Zakey, A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      The impact of climate change on surface ozone over Europe was studied using four offline regional chemistry transport models (CTMs) and one online regional integrated climate-chemistry model (CCM), driven by the same global projection of future climate under the SRES A1B scenario. Anthropogenic emissions of ozone precursors from RCP4.5 for year 2000 were used for simulations of both present and ...