Fakultet for naturvitenskap og teknologi: Nye registreringer
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Mechanisms of enzyme adaptation to extreme environments: The rational design of a thermophilic chorismate mutase
(Doctoral thesis; Doktorgradsavhandling, 2024-02-26)<p>Extremophiles, especially those living in high-temperature environments, exhibit unique enzymatic mechanisms that allow survival under conditions detrimental to most life forms. Of particular interest is thermophiles, which are able to thrive at temperatures at which psychrophiles and mesophiles unfold and cease to function. The mechanisms by which these enzymes are able to overcome this temperature ... -
Preparation of a Compound with a SiII−SiIV−SiII Bonding Arrangement
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-07)Herein, we report the synthesis of a rare bis-silylene, 1, in which two Si<sup>II</sup>atoms are bridged by a Si<sup>IV</sup> atom. Compound 1 contains an unusual Si<sup>II</sup> SiI<sup>V</sup> Si<sup>II</sup> bonding arrangement with Si<sup>II</sup> Si<sup>IV</sup> bond distances of 2.4212(8) and 2.4157(7) Å. Treatment of 1 with Fe(CO)<sub>5</sub> afforded a dinuclear Fe<sup>0</sup>S complex 2 ... -
From Diaminosilylenes to Silapyramidanes: Making Sense of the Stability of Divalent Silicon Compounds
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-07)Since the discovery of decamethylsilicocene over three decades ago, chemists have successfully isolated a variety of divalent silicon compounds by orchestrating steric and electronic effects to their advantage. Two broad strategies of electronic stabilization appear to have been widely deployed, namely, π-conjugation as in diaminosilylenes and π-complexation as in decamethylsilicocene and ... -
Shallow and deep groundwater moderate methane dynamics in a high Arctic glacial catchment
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-07)Glacial groundwater can mobilize deep-seated methane from beneath glaciers and permafrost in the Arctic, leading to atmospheric emissions of this greenhouse gas. We present a temporal, hydro-chemical dataset of methane-rich groundwater collected during two melt seasons from a high Arctic glacial forefield to explore the seasonal dynamics of methane emissions. We use methane and ion concentrations ... -
Sleep Monitoring with Wearable Sensor Data in an eCoach Recommendation System: A Conceptual Study with Machine Learning Approach
(Chapter; Bokkapittel, 2023-04-25)The collective effects of sleep loss and sleep disorders are correlated with many adverse health consequences, including increased risk of high blood pressure, obesity, diabetes, depressive state, and cardiovascular symptoms. Research in eHealth can provide methods to enrich personal health care with information and communication technologies (ICTs). An eCoach system may allow people to manage a ... -
Analysis of dust impacts observed with the Radio Plasma Wave instrument onboard ESA’s Solar Orbiter
(Master thesis; Mastergradsoppgave, 2023-12-15)Dust particles are one of the major constituents of the interplanetary medium in our solar system. They are presumably formed by fragmentation processes of meteoroids and for a certain range of sizes and parameters the dust particles move radially outwards from the Sun. The Radio plasma Wave (RPW) instrument on Solar Orbiter can measure dust particles that impact the spacecraft. By measuring the ... -
On the Distribution of Meteoric Smoke Particles above Andøya, Norway, and Estimated Collection During a Summer Rocket Campaign
(Master thesis; Mastergradsoppgave, 2023-12-21)As meteoroids enter the Earth’s atmosphere, the majority will fully evaporate in the altitude region 70–110 km, due to the frictional heating from atmospheric interactions. The evaporated material is thought to re-condense and coagulate into nanometer sized particles called meteoric smoke particles (MSP). These particles are thought to be a central component in the formation of noctilucent clouds ... -
Wind Turbine System Performance and Reliability Trend Analysis
(Master thesis; Mastergradsoppgave, 2022-01-30)This thesis project is a part of my master’s study course at the department of technology and safety. My thesis is focused on renewable energy, especially analyzing of energy production and technical performance of existing wind turbines within the arctic region. To that end it was important to contact local wind farm owners for operational data exchange. Using partners production and fault related ... -
A southern, middle, and northern Norwegian offshore wind energy resources analysis by a transfer learning method for Energy Internet
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023)As renewable energy sources offshore wind energy develop quickly, countries like Norway with long coastlines are exploring their potential. However, the diverse wind resources across different regions of Norway present challenges for study for effective utilization of offshore wind energy. This study proposes a novel method that utilizes transfer learning techniques to analyse the resource differences ... -
Assessment of the ecological quality status of the Sepetiba Bay (SE Brazil): When metabarcoding meets morphology on foraminifera
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-09)In recent years, the region surrounding Sepetiba Bay (SB; SE Brazil) has become a hub of intense urban expansion and economic exploitation in response to ore transport and industrial and port activities. As a result, contaminants have been introduced into the bay, leading to an overall worsening of the environmental quality. The present work applies for the first time a foraminiferal morphology-based ... -
Sea ice-ocean coupling during Heinrich Stadials in the Atlantic–Arctic gateway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-11)The variability of Arctic sea-ice during abrupt stadial-interstadial shifts in the last glacial period remain poorly understood. Here, we investigated the millennial-scale relationship, with a focus on Heinrich Stadials (HS), between sea-ice cover and bottom water temperature (BWT) during Marine Isotope Stages (MIS) 3 and 2 (64–13 ka) in the Fram Strait using new molecular sea ice biomarker data and ... -
Multi-Agent Collision Avoidance Method Using Fuzzy Risk Estimation and Information Sharing in Unknown Environments
(Chapter; Bokkapittel, 2023-09-22)Automated vehicles within Industry 4.0 are used as logistics units where they can move resources from one place to another safely and efficiently. The automated vehicles can be tasked to work in unknown environments where collision-free navigation is challenging due to uncertainty and lack of environmental information. Collisions can damage equipment and may even cause harm to human workers sharing ... -
Self-Supervised Few-Shot Learning for Ischemic Stroke Lesion Segmentation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-01)Precise ischemic lesion segmentation plays an essential role in improving diagnosis and treatment planning for ischemic stroke, one of the prevalent diseases with the highest mortality rate. While numerous deep neural network approaches have recently been proposed to tackle this problem, these methods require large amounts of annotated regions during training, which can be impractical in the medical ... -
Label-free measurement of antimicrobial peptide interactions with lipid vesicles and nanodiscs using microscale thermophoresis
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-03)One strategy to combat antimicrobial resistance is the discovery of new classes of antibiotics. Most antibiotics will at some point interact with the bacterial membrane to either interfere with its integrity or to cross it. Reliable and efficient tools for determining the dissociation constant for membrane binding (K<sub><i>D</sub></i>) and the partitioning coefficient between the aqueous- and ... -
Comparative analysis of HiSeq3000 and BGISEQ-500 sequencing platform with shotgun metagenomic sequencing data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-29)Recent advances in sequencing technologies and platforms have enabled to generate metagenomics sequences using different sequencing platforms. In this study, we analyzed and compared shotgun metagenomic sequences generated by HiSeq3000 and BGISEQ-500 platforms from 12 sediment samples collected across the Norwegian coast. Metagenomics DNA sequences were normalized to an equal number of bases for ... -
Full Breit Hamiltonian in the Multiwavelets Framework
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-01)New techniques in core–electron spectroscopy are necessary to resolve the structures of oxides of f-elements and other strongly correlated materials that are present only as powders and not as single crystals. Thus, accurate quantum chemical methods must be developed to calculate core spectroscopic properties in such materials. In this contribution, we present an important development in this ... -
Accurate Computation of Thermodynamic Activation Parameters in the Chorismate Mutase Reaction from Empirical Valence Bond Simulations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-19)Chorismate mutase (CM) enzymes have long served as model systems for benchmarking new methods and tools in computational chemistry. Despite the enzymes’ prominence in the literature, the extent of the roles that activation enthalpy and entropy play in catalyzing the conversion of chorismate to prephenate is still subject to debate. Knowledge of these parameters is a key piece in fully understanding ... -
Label-free super-resolution optical microscopy
(Doctoral thesis; Doktorgradsavhandling, 2024-02-06)To see structures well below 200 nm using visible light, super-resolution techniques have been developed. Most of these techniques rely on fluorescence labelling or use of artificial materials to go beyond the Abbe limit. Therefore, achieving super-resolution in the label-free regime is the problem that is being addressed in this thesis. In this work, high-index contrast dielectric waveguides are ... -
Improvements in September Arctic Sea Ice Predictions Via Assimilation of Summer CryoSat-2 Sea Ice Thickness Observations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-15)Because of a spring predictability barrier, the seasonal forecast skill of Arctic summer sea ice is limited by the availability of melt-season sea ice thickness (SIT) observations. The first year-round SIT observations, retrieved from CryoSat-2 from 2011 to 2020, are assimilated into the GFDL ocean–sea ice model. The model's SIT anomaly field is brought into significantly better agreement with the ... -
Scalar Relativistic Effects with Multiwavelets: Implementation and Benchmark
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-05)The importance of relativistic effects in quantum chemistry is widely recognized, not only for heavier elements but throughout the periodic table. At the same time, relativistic effects are strongest in the nuclear region, where the description of electrons through a linear combination of atomic orbitals becomes more challenging. Furthermore, the choice of basis sets for heavier elements is ...