Doktorgradsavhandlinger (NT-fak): Recent submissions
Now showing items 181-200 of 305
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A Biofocussed Chemoprospecting Approach to Drug Discovery: Design, Synthesis and Bioactivity Screening of Diverse Biofocussed Chemical Libraries
(Doctoral thesis; Doktorgradsavhandling, 2017-04-28)With pharma R & D witnessing rising cost, high attrition rates and an overall decline in productivity in recent times, newer approaches are needed for more efficient early phase drug discovery. This thesis describes a new approach, “biofocussed chemoprospecting”. The essence of the approach is to use diverse, yet “bio-like” compounds for efficient hit-finding, along with property filtering and ... -
Surface properties tune thermal adaptation of enzymes - Computational studies of endonuclease A
(Doctoral thesis; Doktorgradsavhandling, 2017-04-26)The endonucleases A from Aliivibrio salmonicida (VsEndA, cold-adapted) and Vibrio cholerae (VcEndA, warm-adapted) have been studied in this work. The goal was to compare these two systems, in order to find structural differences that could explain the mechanism of cold adaptation in the psychrophilic EndA. These two enzymes have previously been studied experimentally and the crystal structures have ... -
Structural determinants of ligand binding to ATP dependent enzymes: Studies of Protein Kinase and Heat Shock Protein 70.
(Doctoral thesis; Doktorgradsavhandling, 2017-04-07)Enzymes are protein molecules that accelerate, or “catalyze”, specific chemical reactions. The reacting molecules, or substrates, bind to the enzyme which then enables their effective conversion into different product molecules. Virtually all metabolic processes in the cell need enzymes to occur at speeds fast enough to maintain life. The kinases are a large group of phosphotransferases, i.e. enzymes ... -
Vertical nitrate fluxes in the Arctic Ocean
(Doctoral thesis; Doktorgradsavhandling, 2017-03-16)Upward mixing of remineralized nutrients is essential for photosynthesis in the upper ocean. Weak vertical mixing, which restricts nutrient supply, and sea ice, which leads to low light levels, conspire to severely inhibit marine primary productivity in the Arctic Ocean. However, little has been known about their relative contributions. No large-scale quantitative estimates of the vertical nutrient ... -
A Data Management Model For Large-Scale Bioinformatics Analysis
(Doctoral thesis; Doktorgradsavhandling, 2017-01-18)Bioinformatics has seen an extreme data growth in later years due to the reduction in cost per megabase of sequencing, which today is around 1/400,000th of the cost in 2001. This reduction in cost enables new types of studies, such as searching for novel enzymes in marine environments using metagenomic approaches. However, it also leads to an increase in volume of data, which shifts overall cost ... -
Lie-Algebraic Approaches to Highly Symmetric Geometries
(Doctoral thesis; Doktorgradsavhandling, 2017-02-24)We facilitate the exploration and development of geometry by symmetry-based methods. To this end, we answer several natural questions that appear when considering symmetries, for particular examples of geometries -
The Polarizable Continuum Model Goes Viral! Extensible, Modular and Sustainable Development of Quantum Mechanical Continuum Solvation Models
(Doctoral thesis; Doktorgradsavhandling, 2017-01-16)Synergistic theoretical and experimental approaches to challenging chemical problems have become more and more widespread, due to the availability of efficient and accurate ab initio quantum chemical models. Limitations to such an approach do, however, still exist. The vast majority of chemical phenomena happens in complex environments, where the molecule of interest can interact with a large number ... -
Trends and variability of polar mesopause region temperatures attributed to atmospheric dynamics and solar activity
(Doctoral thesis; Doktorgradsavhandling, 2016-12-19)The mesopause region can be considered a "boundary region" between the neutral atmosphere, where atmospheric constituents and momentum are transported mainly by winds and turbulent eddies, and the ionosphere, where the main transport mechanism is molecular diffusion. In the mesopause, complex interactions between dynamics and photochemistry occur, and we are far from a complete understanding of these ... -
Mutational, structural and inhibitory investigations of metallo-β-lactamases involved in antibiotic resistance
(Doctoral thesis; Doktorgradsavhandling, 2017-02-16)This thesis focuses on metallo-β-lactamases (MBLs) enzymes that break down a wide variety of antibiotics. Bacteria harboring genes expressing MBLs are antibiotic resistant. If the MBL genes are found on mobile genetic elements, the spread of the genes between bacteria becomes easier. To date, there are no MBL inhibitors available for blocking the enzyme activity, and thus there is an urgent need to ... -
Investigations of summer sea ice with X and C-band multi-polarimetric synthetic aperture radar (SAR)
(Doctoral thesis; Doktorgradsavhandling, 2017-03-17)In this thesis, we explore the possibilities and limitations of using space-borne multi-polarimetric SAR in summer sea ice investigations. Both X and C-band data are examined. The study utilizes two data sets collected in the Arctic in 2011 (Fram Strait) and 2012 (north of Spitsbergen). Both sets combine satellite SAR scenes with co-located ground and air-borne measurements. Firstly, the study ... -
Wind Energy at Nygårdsfjellet – Norway. Wind field characterization and modelling
(Doctoral thesis; Doktorgradsavhandling, 2016-11-25)The research focuses on the characterization of wind flow over complex terrain of Nygårdsfjell and numerical wind flow modelling. In the context to research focus, the main contributions of this research thesis are within the following areas: Characterization of wind flow at the Nygårdsfjell wind farm, situated in the arctic circle in Norway. Wind data is collected from the anemometers installed on ... -
RAM Analysis of Oil and Gas Production Facilities Operating in the Arctic offshore: Expert Judgements and Operating Conditions
(Doctoral thesis; Doktorgradsavhandling, 2016-08-31)The Arctic offshore has a sensitive environment and is associated with a range of harsh operating conditions with considerable year-round variations. Such conditions can adversely affect the reliability, availability, and maintainability (RAM) of oil and gas (O&G) production facilities in different ways. One of the main challenges in RAM analysis of Arctic offshore O&G facilities is the lack of ... -
Carbon Nanotube Spectrally Selective Solar Thermal Absorbers
(Doctoral thesis; Doktorgradsavhandling, 2016-10-04)The main objectives of this work were to investigate a) the feasibility of depositing multi-walled carbon nanotubes (MWCNTs) homogeneously on metal substrates by electrophoresis and b) the performance of MWCNT coatings as spectrally selective absorbers. Stable aqueous MWCNT suspensions were prepared and employed in electrophoretic deposition (EPD) of MWCNT coatings on aluminum substrates. The surface ... -
Improving Latency in Mobile/Cloud Applications
(Doctoral thesis; Doktorgradsavhandling, 2016-08-25)Smartphones are becoming comparable to desktop computers in terms of computational power, and offer diverse applications ranging from social media and gaming, to multimedia and banking. A particular class of mobile applications, mobile/cloud applications, are tightly coupled with the cloud. While executing on the mobile device, they communicate frequently with the cloud for crucial functionality. Use ... -
Machine Learning using Principal Manifolds and Mode Seeking
(Doctoral thesis; Doktorgradsavhandling, 2016-10-14)A wide range of machine learning methods have taken advantage of density estimates and their derivatives, including methodology related to principal manifolds and mode seeking, finding use in a number of real applications. However, research concerned with improving density derivative estimation and its practical use have received relatively limited attention. Also, the fact that the derivatives ... -
A distributed remote presence system for latency critical human-to-human and human-to-computer interaction
(Doctoral thesis; Doktorgradsavhandling, 2016-09-27)In a computer-based distributed stage performance, such as a theater play or opera, the actors and the audiences are spread among different stages in different locations. Actors in different cities can be on the same virtual stage and perform in front of an audience that can enjoy a whole consistent performance. A distributed stage performance raises a set of challenges both of a principled and of ... -
Calculating molecular properties in realistic environments
(Doctoral thesis; Doktorgradsavhandling, 2016-05-13)This thesis focuses on how absorption properties of molecules are influenced by their environment and how this can be calculated accurately. Calculations have been performed with a polarizable embedding (PE) multiscale model. The environment is described classically by charges and electric multipoles for the permanent electrostatics and polarizabilities for polarization interactions. Density-functional ... -
Synthesis of Sterically Hindered Macrocyclic Ligands via Demetalation of Metallocorroles
(Doctoral thesis; Doktorgradsavhandling, 2016-06-07)Despite important developments in synthetic corrole chemistry, the field has long been handicapped by the lack of procedures for demetalation of metallocorroles. This thesis presents general demetalation methods for metallocorroles. A reductive demetalation method was developed using concentrated H2SO4 with 5-200 equivalent of FeCl2 or SnCl2 as a reducing agent. The method proved to be quite general ... -
Past and present natural methane seepage on the northern Norwegian continental shelf
(Doctoral thesis; Doktorgradsavhandling, 2016-06-30)This thesis represents an integrated research effort to understand past and present methane cycling on the northern Norwegian margin. Active hydrocarbon seeps in the Hola trough on the Vesterålen continental shelf are found to be fed predominantly by thermogenic methane (and ethane, propane and butane). Most likely derived from Late Jurassic to Early Cretaceous source rocks, these gaseous hydrocarbons ... -
Geoelectrical structures beneath Spitsbergen-Svalbard derived from magnetotelluric imaging
(Doctoral thesis; Doktorgradsavhandling, 2016-05-27)In this thesis a series of geophysical surveys are carried out on the geologically important and remote Svalbard using magnetotelluric imaging, to constrain better the geology particularly defining geothermal resources. Magnetotellurics (MT) relays on natural source time-varying electric and magnetic field data measured at the earth’s surface in order to derive the subsurface resistivity structure. ...