Dag Kristian Dysthe

• Demir, Ali Aslan; Combriat, Thomas Michel Daniel; Heyward, Catherine Anne; Tiainen, Hanna; Carlier, Aurélie & Dysthe, Dag Kristian (2026). A cellular automaton model of osteogenic differentiation reveals identifiability limits of endpoint assays. Frontiers in Systems Biology. 6. doi: 10.3389/fsysb.2026.1872774. Fulltekst i vitenarkiv Vis sammendrag

  Introduction Standard differentiation assays sample cell states only at discrete time points, while the underlying progression unfolds continuously and heterogeneously across cells. As a result, different combinations of proliferation, commitment, and maturation dynamics can converge to similar endpoint measurements. This many-to-one mapping between latent trajectories and observable readouts constitutes a partially observed inverse problem that limits mechanistic interpretation. Although this ambiguity is inherent to many experimental systems, it is rarely examined using models that connect cell-state dynamics to assay-level quantities. Methods We present OsteoMin, a coarse-grained cellular automaton that links stochastic transitions between pre-osteoblast and osteoblast states to experimentally measurable readouts of alkaline phosphatase activity, collagen deposition, and mineralization. Model parameters were constrained using literature-reported kinetics and evaluated against dexamethasone and menaquinone-4 perturbations. The framework enables systematic analysis of how cell-state progression, matrix maturation, and external perturbations shape differentiation outcomes. Results OsteoMin reproduces qualitative assay trends and quantifies the identifiability limits of endpoint assays. Distinct perturbation families often produce similar endpoint responses (macro-F1 ≈ 0.42$), indicating limited discriminative power. Incorporating temporal trajectories improves separability (macro-F1 ≈ 0.78$), demonstrating that most identifiable information resides in marker dynamics rather than terminal measurements. Sobol analysis shows that early markers depend on proliferation timing, whereas late mineralization is governed by nonlinear matrix maturation and parameter interactions. Discussion These results show that endpoint assays constrain overall progression but do not uniquely identify underlying mechanisms. OsteoMin provides a framework linking differentiation dynamics to assay observables and a basis for assessing identifiability in endpoint-driven systems.

• Låstad, Silja Borring; Abbasova, Nigar; Combriat, Thomas Michel Daniel & Dysthe, Dag Kristian (2026). Three Dimensional Dynamics of Epithelial Monolayers. BioaRxiv. doi: 10.64898/2026.03.10.710903. Fulltekst i vitenarkiv Vis sammendrag

  Cells in epithelial monolayers are commonly quantified using a projected area and implicitly assuming constant cell volume and prism-shaped cells. These 2.5D assumptions ignore the volume and mass dynamics that may accompany density fluctuation in confluent space-filling tissues but remain inaccessible to the labelling- and intensity-based imaging techniques used to date. Here, we use time-lapse quantitative phase imaging (QPI) to obtain spatially and temporally resolved maps of height, volume, and dry mass in MDCK epithelial monolayers under physiological conditions. Three findings follow. (i) Cellular dry mass concentration is maintained to within ∼ 4.5 % across the monolayer and over time, even during large-amplitude pulsations, ruling out fluid (water) transport as the dominant driver of height and area dynamics. (ii) The mean height of the monolayer increases from ∼ 5.5 to ∼ 9 µm and the mean cell volume decreases by ∼ 25 % as the cell density doubles, evidence of contact inhibition of cell size rather than constant cell volume. Cell heights vary up to 30%, oscillate with a ∼ 5 h period, and follow gamma-shaped distributions. (iii) At cellular scales, both segmented-cell tracking and continuum mass-flux analysis show that projected cell volume is not conserved; mass conservation is recovered only after coarse-graining over ∼ 2 cell diameters and ∼ 1.6 h. Two non-exclusive mechanisms may explain this: non-prismatic cell geometry produces apparent volume fluctuations even at constant true volume, and periodic mass exchange between cells and the ECM produces genuine cyclic changes in cellular dry mass. A propagating elastic mode in the dry-mass structure factor ( c s ∼ 15 µm/h) further indicates that the monolayer behaves as a viscoelastic active medium rather than a plug-flow fluid. Each of these results requires simultaneous, time-resolved access to height and dry mass at the cellular scale and is therefore newly visible with QPI applied to epithelial monolayers. Together, they question the common 2.5D assumptions of prism-shaped cells, constant volume, plug-flow kinematics, and argue that quantitative continuum and cell-based models of epithelial dynamics must incorporate dry-mass-density regulation and 3D cell geometry.

• Schöb, Franziska Jessica; Binder, Alexander; Zamarian, Valentina; Sordi, Valeria; Scholz, Hanne & Malthe-Sørenssen, Anders [Vis alle 7 forfattere av denne artikkelen] (2026). Deep learning for predicting stem cell efficiency for use in beta cell differentiation. Scientific Reports. 16(1). doi: 10.1038/s41598-026-42830-3. Fulltekst i vitenarkiv Vis sammendrag

  Recent clinical trial data show curative potential of cell therapy for diabetes, however the cells required are a bottleneck. Cell differentiation exhibits substantial variability, even among clones of stem cells generated from the same patient. Human experts struggle to see the difference between highly- and lowly-efficient cell clones early. We therefore propose an image-based deep learning model to guide the selection of the most efficient clones. We apply different deep learning models to learn the morphological differences between good and bad stem cell clones and classify them based on phase-contrast imaging. To gain insight into the learned features, we use layer-wise relevance propagation, and Fourier-based frequency analysis. Using an EfficientNet-V2-S model, we obtain a novel early prediction for the outcome of the differentiation process from patient-derived stem cells to β -cells using imaging. Clone level accuracy is 96.7 % at 53 hours after start of differentiation. The analysis of learned features shows that the structure of the cell population is an important predictive feature. This study is a proof-of-concept that deep learning combined with label-free imaging can be highly predictive and guide selection of stem cell clones, thereby reducing cost of β -cell production.

• Låstad, Silja Borring; Abbasova, Nigar; Combriat, Thomas Michel Daniel & Dysthe, Dag Kristian (2026). Quantitative Phase Imaging of the Dynamics of Epithelial Monolayers. SPIE Quantitative Phase Imaging XII. 13861. doi: 10.1117/12.3084036. Fulltekst i vitenarkiv Vis sammendrag

  This study uses two different quantitative phase imaging techniques (QPI) and for the first time measures the height, volume, and mass dynamics of Madin-Darby Canine Kidney (MDCK) monolayers. We demonstrate novel methods to determine the height of confluent monolayers of cells from 2D and 3D QPI data and validate that the two methods agree. We developed a novel cell segmentation method adapted to QPI images of confluent cell layers and present a robust measure of relative error. We also demonstrate that height statistics of cells can be obtained without segmenting the images. We obtain the following precisions of cell density (1 %), height (3 %), area (5 %) and volume (6 %). Cell height varies 15-25 % over a monolayer and increases 50-100 % when cell density doubles. The average refractive index and the dry mass fraction of the cells, on the other hand, are constant over the entire density range.

• Ho, Richard David Jun-Geet; Mossige, Joachim; Ponomartcev, Sergei; Natalia, Smirnova,; Sunny, Dai, Keqing & Hu, Xian [Vis alle 9 forfattere av denne artikkelen] (2025). [2509.08929] Spontaneous elongation of 3D gastruloids from local cell polarity alignment. arXiv. doi: https:/arxiv.org/abs/2509.08929. Fulltekst i vitenarkiv Vis sammendrag

  Gastruloids are 3D stem cell aggregate models for early embryogenesis that provide a unique platform to study how collective cell dynamics drive tissue symmetry breaking and axial elongation. Using 3D light sheet imaging, we show that a pulse of Chiron, a Wnt activator, induces coherent alignment of cell polarity during elongation. While nuclear elongation occurs with or without treatment, only Chiron-treated gastruloids exhibit quasi-long-range alignment of nuclear axes, linking cell polarity coherence to tissue-scale remodeling. A minimal physical model of polarized cells, incorporating alignment-dependent torques and polarity-mediated adhesion, reproduces symmetry breaking and elongation, demonstrating that local cell polarity alignment alone can drive tissue-scale convergence-extension flows.

• Ho, Richard David Jun-Geet; Bøe, Stig Ove; Dysthe, Dag Kristian & Angheluta, Luiza (2024). Role of tissue fluidization and topological defects in epithelial tubulogenesis. Physical Review Research (PRResearch). 6(2), s. 1–10. doi: 10.1103/PhysRevResearch.6.023315. Fulltekst i vitenarkiv Vis sammendrag

  Cellular rearrangements, as primary sources of tissue fluidization, facilitate topological transitions during tissue morphogenesis. We study the role of intrinsic cell properties such as cell polarity and cell-cell adhesion in shaping epithelial tissues using a minimal model of interacting polarized cells. The presence of a vortex in the cell polarization poses the topological constraint that induces an inwards migration with the formation of a conical shape. Local rearrangements at the tip of the cone lead to the onset of tube formation. Switching between collective migration and structural rearrangements is key for balancing the contrasting tendencies, such as the tissue rigidity needed to preserve shape and the tissue fluidity allowing for topological transitions during tissue morphogenesis.

• Combriat, Thomas Michel Daniel; Dysthe, Dag Kristian & Flekkøy, Eirik Grude (2024). Cavitation dynamics in creeping flow. Journal of Fluid Mechanics. ISSN 0022-1120. 999. doi: 10.1017/jfm.2024.937. Fulltekst i vitenarkiv Vis sammendrag

  We investigate the heterogeneous cavitation phenomenon in water when a spherical surface is abruptly separated from a nearby flat substrate, at a distance of approximately 10 nm. By tracking the surface separation using Newton ring positions, and capturing the bubble evolution with a high-speed camera on a microscope, we compare our experimental findings with hydrodynamic predictions at low Reynolds numbers. Upon upward movement of the spherical surface, the resulting bubble develops branched fingers through the Saffman–Taylor instability. Simultaneously, negative liquid pressures in the range ∼ 10 atm are observed. These large tension values occasionally lead to secondary nucleation events. The bubble sizes satisfy a predicted Family–Vicsek scaling law where the bubble area is proportional to the inverse bubble lifetime. The fact that creeping flow cavitation bubbles are more short-lived the larger they are separates them from bubbles that are governed by inertial dynamics.

• Combriat, Thomas Michel Daniel; Olsen, Petter Angell; Låstad, Silja Borring; Malthe-Sørenssen, Anders; Krauss, Stefan Johannes Karl & Dysthe, Dag Kristian (2024). Acoustic Wave-Induced Stroboscopic Optical Mechanotyping of Adherent Cells. Advanced Science. 11(16). doi: 10.1002/advs.202307929. Fulltekst i vitenarkiv Vis sammendrag

  In this study, a novel, high content technique using a cylindrical acoustic transducer, stroboscopic fast imaging, and homodyne detection to recover the mechanical properties (dynamic shear modulus) of living adherent cells at low ultrasonic frequencies is presented. By analyzing the micro-oscillations of cells, whole populations are simultaneously mechanotyped with sub-cellular resolution. The technique can be combined with standard fluorescence imaging allowing to further cross-correlate biological and mechanical information. The potential of the technique is demonstrated by mechanotyping co-cultures of different cell types with significantly different mechanical properties.

• Kohler, Felix; Pierre-Louis, Olivier & Dysthe, Dag Kristian (2022). Crystal growth in confinement. Nature Communications. 13(1), s. 1–8. doi: 10.1038/s41467-022-34330-5. Fulltekst i vitenarkiv Vis sammendrag

  Abstract The growth of crystals confined in porous or cellular materials is ubiquitous in Nature and forms the basis of many industrial processes. Confinement affects the formation of biominerals in living organisms, of minerals in the Earth’s crust and of salt crystals damaging porous limestone monuments, and is also used to control the growth of artificial crystals. However, the mechanisms by which confinement alters crystal shapes and growth rates are still not elucidated. Based on novel in situ optical observations of (001) surfaces of NaClO 3 and CaCO 3 crystals at nanometric distances from a glass substrate, we demonstrate that new molecular layers can nucleate homogeneously and propagate without interruption even when in contact with other solids, raising the macroscopic crystal above them. Confined growth is governed by the peculiar dynamics of these molecular layers controlled by the two-dimensional transport of mass through the liquid film from the edges to the center of the contact, with distinctive features such as skewed dislocation spirals, kinetic localization of nucleation in the vicinity of the contact edge, and directed instabilities. Confined growth morphologies can be predicted from the values of three main dimensionless parameters.

• Gløersen, Øyvind Nøstdahl; Colosio, Alessandro L.; Boone, Jan; Dysthe, Dag Kristian; Malthe-Sørenssen, Anders & Capelli, Carlo [Vis alle 7 forfattere av denne artikkelen] (2022). Modeling V̇o2 on-kinetics based on intensity-dependent delayed adjustment and loss of efficiency (DALE). Journal of applied physiology. ISSN 8750-7587. 132(6), s. 1480–1488. doi: 10.1152/japplphysiol.00570.2021. Fulltekst i vitenarkiv Vis sammendrag

  This study presents and evaluates a new mathematical model of V̇o2 on-kinetics, with the following properties: 1) a progressively slower primary phase following the size-principle of motor unit recruitment, explaining the delayed V̇o2 steady state seen in the heavy exercise intensity domain, and 2) a severe-domain slow component modeled as a time-dependent decrease in efficiency. Breath-by-breath V̇o2 measurements from eight subjects performing step cycling transitions, in the moderate, heavy, and severe exercise domains, were fitted to the conventional three-phase model and the new model. Model performance was evaluated with a residual analysis and by comparing Bayesian (BIC) and corrected Akaike (AICc) information criteria. The residual analysis showed no systematic deviations, except perhaps for the initial part of the primary phase. BIC favored the new model, being 9.3 (SD 7.1) lower than the conventional model whereas AICc was similar between models. Compared with the conventional three-phase model, the proposed model distinguishes between the kinetic adaptations in the heavy and severe domains by predicting a delayed steady-state V̇o2 in the heavy and no steady-state V̇o2 in the severe domain. This allows to determine when stable oxygen costs of exercise are attainable and it also represents a first step in defining time-dependent oxygen costs when stable energy conversion efficiency is not attainable. NEW & NOTEWORTHY: We propose and assess a new minimalistic integrated model for the V̇o2 on-kinetics, inspired by the currently available best evidence of the underlying mechanisms. We show that the model provides a similar fit as the conventionally used three-phase model, even though a stricter data fitting method is used for the proposed model. The proposed model clarifies misconceptions related to the V̇o2 slow component’s behavior, by clearly predicting that steady-state V̇o2 is attainable in the moderate and heavy exercise intensity domains. Furthermore, the model opens new possibilities for assessing oxygen cost during severe intensity exercise without the fallible assumption of time-constant energy-conversion efficiency.

• Li, Lei; Kohler, Felix; Dziadkowiec, Joanna; Røyne, Anja; Marzal, Rosa M. Espinosa & Bresme, Fernando [Vis alle 8 forfattere av denne artikkelen] (2022). Limits to Crystallization Pressure. Langmuir. ISSN 0743-7463. 38(37), s. 11265–11273. doi: 10.1021/acs.langmuir.2c01325. Fulltekst i vitenarkiv Vis sammendrag

  Crystallization pressure drives deformation and damage in monuments, buildings, and the Earth’s crust. Even though the phenomenon has been known for 170 years, there is no agreement between theoretical calculations of the maximum attainable pressure and experimentally measured pressures. We have therefore developed a novel experimental technique to image the nanoconfined crystallization process while controlling the pressure and applied it to calcite. The results show that displacement by crystallization pressure is arrested at pressures well below the thermodynamic limit. We use existing molecular dynamics simulations and atomic force microscopy data to construct a robust model of the disjoining pressure in this system and thereby calculate the absolute distance between the surfaces. On the basis of the high-resolution experiments and modeling, we formulate a novel mechanism for the transition between damage and adhesion by crystallization that may find application in Earth and materials sciences and in conservation of cultural heritage.

• Chelly, H.; Jahangiri, a; Mireux, M.; Etienne, J; Dysthe, Dag Kristian & Verdier, Jean Michel [Vis alle 7 forfattere av denne artikkelen] (2021). Cell crawling on a compliant substrate: A biphasic relation with linear friction. International Journal of Non-Linear Mechanics. ISSN 0020-7462. doi: 10.1016/j.ijnonlinmec.2021.103897. Fulltekst i vitenarkiv Vis sammendrag

  A living cell actively generates traction forces on its environment with its actin cytoskeleton. These forces deform the cell elastic substrate which, in turn, affects the traction forces exerted by the cell and can consequently modify the cell dynamics. By considering a cell constrained to move along a one-dimensional thin track, we take advantage of the problem geometry to explicitly derive the effective law that describes the non-local frictional contact between the cell and the deformable substrate. We then couple such a law with one of the simplest model of the active flow within the cell cytoskeleton. This offers a paradigm that does not invoke any local non-linear friction law to explain that the relation between the cell steady state velocity and the substrate elasticity is non linear as experimentally observed. Additionally, we present an experimental platform to test our theoretical predictions. While our efforts are still not conclusive in this respect as more cell types need to be investigated, our analysis of the coupling between the substrate displacement and the actin flow leads to friction coefficient estimates that are in-line with some previously reported results.

• Ruiter, Lisa de; Gunnæs, Anette Eleonora; Dysthe, Dag Kristian & Austrheim, Håkon Olaf (2021). Quartz dissolution associated with magnesium silicate hydrate cement precipitation. Solid Earth (SE). ISSN 1869-9510. 12(2), s. 389–404. doi: 10.5194/se-12-389-2021. Fulltekst i vitenarkiv
• Kandula, Neelima; McBeck, Jessica Ann; Cordonnier, Benoît; Weiss, Jérôme; Dysthe, Dag Kristian & Renard, François (2021). Synchrotron 4D X-Ray Imaging Reveals Strain Localization at the Onset of System-Size Failure in Porous Reservoir Rocks. Pure and Applied Geophysics (PAGEOPH). ISSN 0033-4553. 179, s. 325–350. doi: 10.1007/s00024-021-02902-z. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Understanding the mechanisms of strain localization leading to brittle failure in reservoir rocks can shed light on geomechanical processes such as porosity and permeability evolution during rock deformation, induced seismicity, fracturing, and subsidence in geological reservoirs. We perform triaxial compression tests on three types of porous reservoir rocks to reveal the local deformation mechanisms that control system-size failure. We deformed cylindrical samples of Adamswiller sandstone (23% porosity), Bentheim sandstone (23% porosity), and Anstrude limestone (20% porosity), using an X-ray transparent triaxial deformation apparatus. This apparatus enables the acquisition of three-dimensional synchrotron X-ray images, under in situ stress conditions. Analysis of the tomograms provide 3D distributions of the microfractures and dilatant pores from which we calculated the evolving macroporosity. Digital volume correlation analysis reveals the dominant strain localization mechanisms by providing the incremental strain components of pairs of tomograms. In the three rock types, damage localized as a single shear band or by the formation of conjugate bands at failure. The porosity evolution closely matches the evolution of the incremental strain components of dilation, contraction, and shear. With increasing confinement, the dominant strain in the sandstones shifts from dilative strain (Bentheim sandstone) to contractive strain (Adamswiller sandstone). Our study also links the formation of compactive shear bands with porosity variations in Anstrude limestone, which is characterized by a complex pore geometry. Scanning electron microscopy images indicate that the microscale mechanisms guiding strain localization are pore collapse and grain crushing in sandstones, and pore collapse, pore-emanated fractures and cataclasis in limestones. Our dynamic X-ray microtomography data brings unique insights on the correlation between the evolutions of rock microstructure, porosity evolution, and macroscopic strain during the approach to brittle failure in reservoir rocks.

• Gløersen, Øyvind Nøstdahl; Gilgien, Matthias; Dysthe, Dag Kristian; Malthe-Sørenssen, Anders & Losnegard, Thomas Johansen (2020). Oxygen Demand, Uptake, and Deficits in Elite Cross-country Skiers during a 15-km Race. Medicine & Science in Sports & Exercise. ISSN 0195-9131. 52(4), s. 983–992. doi: 10.1249/MSS.0000000000002209. Fulltekst i vitenarkiv Vis sammendrag

  Purpose: To quantify the repeated oxygen deficits attained during intermittent endurance exercise by measuring oxygen consumption (V[Combining Dot Above]O2) and oxygen demand (V[Combining Dot Above]O2dem) throughout a simulated roller ski race. Methods: Eight male elite cross-country skiers (V[Combining Dot Above]O2,peak 77.4 ± 4.4 mL·min-1·kg-1) raced a 13.5 km roller ski time-trial on a World Cup course. On two additional days, athletes completed (i) 6 sub-maximal loads (à 5 min) and a ~ 4 min maximal trial to establish athlete-specific estimates of skiing economy, V[Combining Dot Above]O2,peak, and maximal ΣO2def (MAOD); and (ii) a simulation of the time-trial on a roller skiing treadmill. During the simulation, external work rate (Pprop) and skiing speed (v) were adjusted to match the Pprop and v measured during the time-trial, and pulmonary V[Combining Dot Above]O2 was measured breath-by-breath. V[Combining Dot Above]O2dem and ΣO2def were calculated using an athlete-specific model for skiing economy throughout the treadmill simulation. Results: During the treadmill simulation V[Combining Dot Above]O2 was on average 0.77V[Combining Dot Above]O2,peak, and active V[Combining Dot Above]O2dem, (i.e., excluding the time in simulated downhills), was on average 1.01V[Combining Dot Above]O2,peak. The athletes repeatedly attained substantial oxygen deficits in individual uphill sections of the treadmill simulation, but the deficits were typically small compared to their MAOD (average 14%, range ~0-50%). However, the ΣO2def summed over all periods of active propulsion was on average 3.8MAOD. Conclusion: Athletes repeatedly attain substantial oxygen deficits in the uphill segments of a distance cross-country ski race. Furthermore, the total accumulated oxygen deficit of all these segments is several times higher than the athletes’ MAODs. This suggests that rapid recovery of the energy stores represented by the oxygen deficit is necessary during downhill sections, and that this might be an important determinant of distance skiing performance.

• Sanchez, Jesus Rodriguez; Liberto, Teresa; Barentine, Catherine & Dysthe, Dag Kristian (2020). Mechanisms of phase transformation and creating mechanical strength in a sustainable calcium carbonate cement. Materials. 13(16). doi: 10.3390/MA13163582. Fulltekst i vitenarkiv Vis sammendrag

  Calcium carbonate cements have been synthesized by mixing amorphous calcium carbonate and vaterite powders with water to form a cement paste and study how mechanical strength is created during the setting reaction. In-situ X-ray diffraction (XRD) was used to monitor the transformation of amorphous calcium carbonate (ACC) and vaterite phases into calcite and a rotational rheometer was used to monitor the strength evolution. There are two characteristic timescales of the strengthening of the cement paste. The short timescale of the order 1 h is controlled by smoothening of the vaterite grains, allowing closer and therefore adhesive contacts between the grains. The long timescale of the order 10–50 h is controlled by the phase transformation of vaterite into calcite. This transformation is, unlike in previous studies using stirred reactors, found to be mainly controlled by diffusion in the liquid phase. The evolution of shear strength with solid volume fraction is best explained by a fractal model of the paste structure.

• Høgberget, Jørgen; Røyne, Anja; Dysthe, Dag Kristian & Jettestuen, Espen (2020). Microscopic modeling of contact formation between confined surfaces in solution. arXiv.org. ISSN 2331-8422. Fulltekst i vitenarkiv Vis sammendrag

  We derive a Kinetic Monte Carlo model for studying how contacts form between confined surfaces in an ideal solution. The model incorporates repulsive and attractive surface-surface forces between a periodic (2+1)-dimensional solid-on-solid (SOS) crystal surface and a confining flat surface. The repulsive interaction is derived from the theory of electric double-layers, and the attractive interactions are Van der Waals interactions between particles on the SOS surface and the confining surface. The confinement is induced by a constant external pressure normal to the surfaces which is in mechanical equilibrium with the surface-surface forces. The system is in thermal equilibrium, and particles can deposit to and dissolve from the SOS surface. The size of stable contacts formed between the surfaces in chemical equilibrium show a non-trivial dependency on the external pressure which is phenomenologically similar to the dependency of oscillatory hydration forces on the surface-surface separation. As contacts form we find classical phenomena such as Ostwald ripening, coalescence, and primary and secondary nucleation stages. We find contacts shaped as islands, bands or pits, depending solely on the contact size relative to the system size. We also find the model to behave well out of chemical equilibrium. The model is relevant for understanding processes where the force of crystallization and pressure solution are key mechanisms.

• Høgberget, Jørgen; Dysthe, Dag Kristian & Jettestuen, Espen (2020). Direct Coupling of Free Diffusion Models to Microscopic Models of Confined Crystal Growth and Dissolution. arXiv.org. ISSN 2331-8422. Fulltekst i vitenarkiv Vis sammendrag

  We couple a free solute diffusion model to a model of crystal surface growth represented by, but not limited to, a (2 + 1)-dimensional solid-on-solid (SOS) model confined by a flat surface. We use kinetic Monte Carlo (KMC) with dissolution rates based on nearest-neighbor interactions to solve the Master equation for the surface dynamics, and we use an offlattice random walk to model the Fickian diffusion of the solute particles. The two solvers are coupled directly through deposition rates of the free particles calculated using the mean first passage time (MFPT) of deposition that is found to scale as r−4. Two variants are studied: ignoring (radial) and not ignoring the line of sight (pathfinding). Reference models such as uniform concentration (random deposition) and lattice diffusion (crystal lattice extended into the liquid) are used for comparison. We find that the macroscopic limit of the surface dynamics is reproduced by all models. The free diffusion models produce a lower equilibrium roughness and a smaller height autocorrelation length than the reference models, and are found to behave very well in tight confinements. It is also demonstrated that lattice diffusion does not work well in tight confinements. The two MFPT models behave very similarly close to equilibrium and for dissolution, but becomes increasingly different with increasing surface growth speed. The model is put to use by simulating a cavity with a flux boundary condition at one side. The conclusion is that the new model excels in confinement, and line of sight can in practice be ignored since the dominant deposition sites likely are in line of sight, which minimizes the CPU-time needed in the coupling.

• Panahi, Hamed; Kobchenko, Maya; Meakin, Paul; Dysthe, Dag Kristian & Renard, Francois (2019). Fluid expulsion and microfracturing during the pyrolysis of an organic rich shale. Fuel. ISSN 0016-2361. 235, s. 1–16. doi: 10.1016/j.fuel.2018.07.069. Fulltekst i vitenarkiv Vis sammendrag

  During progressive burial, low permeability organic-rich shale rocks evolve chemically and physically as the temperature and stress increase and organic matter matures. The transformation of organic matter into hydrocarbon, followed by its expulsion into secondary migration pathways along which it is conveyed into reservoirs rocks, is a coupled process that involves chemical reactions, changes in volume and stress leading to the nucleation and growth of microfractures, the opening and closing of these microfractures, and fluid transport through them. Primary migration was studied using an experimental setup that was designed to measure changes in fluid pressure, which are correlated with organic matter maturation and hydrocarbon expulsion. The setup consisted of a pressurized autoclave which was externally heated. Shale samples were confined, under an initially low confining pressure and an applied differential stress (0.18 MPa), and heated to temperatures of 210–320 °C. Changes in temperature, static pressure (pressure measured using a linear response transducer) and dynamic fluid pressures (measured using a piezoelectric differential transducer) in the autoclave chamber were monitored and recorded during each experiment. In the higher part of the temperature range, fluid produced by kerogen maturation and the concomitant formation of microfractures increased volumetric expansion of the shale. Power spectral densities of the fluid pressure signals were calculated and a conceptual model is proposed to explain the dynamics of fluid expulsions. While a power law distribution of frequencies of pressure burst amplitudes was identified, the frequencies of time intervals between successive expulsion events (waiting times) decrease monotonically with increasing waiting time. Co-generation of gas and liquid hydrocarbon was evidenced. Several samples were imaged after kerogen maturation using X-ray microtomography, and the data confirm the existence of a percolating network of microfracture that controls the primary migration of hydrocarbons.

• Renard, Francois; McBeck, Jessica Ann; Cordonnier, Benoit; Zheng, Xiaojiao; Kandula, Neelima & Sanchez, Jesus Rodriguez [Vis alle 12 forfattere av denne artikkelen] (2019). Dynamic In Situ Three-Dimensional Imaging and Digital Volume Correlation Analysis to Quantify Strain Localization and Fracture Coalescence in Sandstone. Pure and Applied Geophysics (PAGEOPH). ISSN 0033-4553. 176, s. 1083–1115. doi: 10.1007/s00024-018-2003-x. Fulltekst i vitenarkiv Vis sammendrag

  Advances in triaxial compression deformation apparatus design, dynamic X-ray microtomography imaging, data analysis techniques, and digital volume correlation analysis provide unparalleled access to the in situ four-dimensional distribution of developing strain within rocks. To demonstrate the power of these new techniques and acquire detailed information about the micromechanics of damage evolution, deformation, and failure of porous rocks, we deformed 3-cm-scale cylindrical specimens of low-porosity Fontainebleau sandstone in an X-ray-transparent triaxial compression apparatus, and repeatedly recorded three-dimensional tomograms of the specimens as the differential stress was increased until macroscopic failure occurred. Experiments were performed at room temperature with confining pressure in the range of 10–20 MPa. Distinct grayscale subsets, indicative of density, enabled segmentation of the three-dimensional tomograms into intact rock matrix, pore space, and fractures. Digital volume correlation analysis of pairs of tomograms provided time series of three-dimensional incremental strain tensor fields throughout the experiments. After the yield stress was reached, the samples deformed first by dilatant opening and propagation of microfractures, and then by shear sliding via grain rotation and strain localization along faults. For two samples, damage and dilatancy occurred by grain boundary opening and then a sudden collapse of the granular rock framework at failure. For the third sample, a fault nucleated near the yield point and propagated in the sample through the development of transgranular microfractures. The results confirm findings of previous experimental studies on the same rock and provide new detailed quantifications of: (1) the proportion of shear versus dilatant strain in the sample, (2) the amount of dilatancy due to microfracture opening versus pore opening when a fault develops, and (3) the role of grain boundaries and pore walls in pinning microfracture propagation and slowing down the rate of damage accumulation as failure is approached. Our study demonstrates how the combination of high-resolution in situ dynamic X-ray microtomography imaging and digital volume image correlation analysis can be used to provide additional information to unravel brittle failure processes in rocks under stress conditions relevant to the upper crust.

• Kandula, Neelima; Cordonnier, Benoit; Boller, Elodie; Weiss, Jérôme; Dysthe, Dag Kristian & Renard, Francois (2019). Dynamics of microscale precursors during brittle compressive failure in Carrara marble. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 124(6), s. 6121–6139. doi: 10.1029/2019JB017381. Fulltekst i vitenarkiv Vis sammendrag

  Microscale heterogeneities influence failure mechanisms in the crust. To track the microstructural changes in rock samples when loaded until failure, we employed a novel experimental technique that couples dynamic X‐ray microtomography imaging with a triaxial deformation apparatus. We studied the brittle failure of Carrara marble under triaxial compression. Dynamic tomographic data revealed the spatial organization of microfractures and damage increments characterizing the precursory activity toward catastrophic failure. We quantified the emergence of scaling relationships between microstructural parameters, including total damage volume, incremental damage volume, the largest connected microfracture, and the applied differential stress. The total volume of microfractures accumulated from the beginning of the experiment as well as the incremental damage showed power law increase. The growth of the largest connected microfracture was related to differential stress as a power law with divergence at failure. The microfracture volume increments were distributed according to a power law with an upper cutoff that itself spanned the entire volume toward failure. These characteristic features of brittle failure in Carrara marble under compression are in agreement with theoretical models that consider failure as a critical phase transition. We also observed that, very close to failure, several power law relationships broke down, which we interpret to be related to the coalescence of the largest microfractures in a finite size volume. Scaling laws and associated exponents computed from our data are compared with predictions made from theoretical and numerical models. Our results show that precursors of macroscopic brittle failure in Carrara marble follow predictable trends.

• Sanchez, Jesus Rodriguez; Myszka, Barbara; Boccaccini, Aldo Roberto & Dysthe, Dag Kristian (2019). Setting behavior and bioactivity assessment of calcium carbonate cements. Journal of The American Ceramic Society. ISSN 0002-7820. 102(11), s. 6980–6990. doi: 10.1111/jace.16593. Fulltekst i vitenarkiv Vis sammendrag

  Calcium carbonate cements have emerged in the last few years as an attractive candidate for biomedical applications. They can be easily prepared by mixing water with two metastable calcium carbonate phases––amorphous calcium carbonate (ACC) and vaterite––which (re)crystallize into calcite during setting reaction. The transformation kinetics (and therefore the final surface cement composition) strongly depends on the initial mixture design and is controlled by the dissolution of ACC, whereas calcite nucleation typically controls their recrystallization in fluid batch experiments. Novel compositions are presented in this paper by incorporating organic molecules as a proxy to test their capability to carry on other biomolecules like proteins or antibiotics. The hardened samples are microporous and show excellent bioactivity rates, although their mechanical properties still remain poor. However, this would not be a handicap for in‐vivo applications such as bone filling, especially in low mechanical stress locations.

• Dziadkowiec, Joanna; Zareeipolgardani, Bahareh; Dysthe, Dag Kristian & Røyne, Anja (2019). Nucleation in confinement generates long-range repulsion between rough calcite surfaces. Scientific Reports. 9. doi: 10.1038/s41598-019-45163-6. Fulltekst i vitenarkiv Vis sammendrag

  Fluid-induced alteration of rocks and mineral-based materials often starts at confined mineral interfaces where nm-thick water films can persist even at high overburden pressures and at low vapor pressures. These films enable transport of reactants and affect forces acting between mineral surfaces. However, the feedback between the surface forces and reactivity of confined solids is not fully understood. We used the surface forces apparatus (SFA) to follow surface reactivity in confinement and measure nm-range forces between two rough calcite surfaces in NaCl, CaCl2, or MgCl2 solutions with ionic strength of 0.01, 0.1 or 1 M. We observed long-range repulsion that could not be explained by changes in calcite surface roughness, surface damage, or by electrostatic or hydration repulsion, but was correlated with precipitation events which started at µm-thick separations. We observed a submicron-sized precipitate that formed in the confined solution. This liquid-like viscous precipitate did not undergo any spontaneous ripening into larger crystals, which suggested that confinement prevented its dehydration. Nucleation was significantly postponed in the presence of Mg2+. The long-range repulsion generated by nucleation between confined mineral surfaces can have a crucial influence on evolution of the microstructure and therefore the macroscopic strength of rocks and materials.

• Li, Lei; Sanchez, Jesus Rodriguez; Kohler, Felix; Røyne, Anja & Dysthe, Dag Kristian (2018). Microfluidic control of nucleation and growth of CaCO3. Crystal Growth & Design. ISSN 1528-7483. 18(8), s. 4528–4535. doi: 10.1021/acs.cgd.8b00508. Fulltekst i vitenarkiv Vis sammendrag

  A novel method for studying nucleation and growth of CaCO3 crystals in situ has been developed and tested rigorously. We demonstrate that precise flow control is essential and how this is achieved. The method has the advantage that one may study single crystals of polymorphs that are thermodynamically unstable in collections of many crystals and that one obtains precise and accurate growth rates without any extra assumptions. We also demonstrate that, at low supersaturations where 2D nucleation does not occur, we measure the growth rate constant of calcite to be 5 times larger than that reported by batch methods and 2 orders of magnitude larger than that measured by atomic force microscopy. Considering the large interest in calcite growth in, for example, geoscience, environmental science, and industry, it is important to explain the discrepancy of growth rate constants between different methods. The method presented here can easily be applied to many other minerals.

• Panahi, Hamed; Kobchenko, Maya; Meakin, Paul; Dysthe, Dag Kristian & Renard, Francois (2018). In-situ imaging of fracture development during maturation of an organic-rich shale: Effects of heating rate and confinement. Marine and Petroleum Geology. ISSN 0264-8172. 95, s. 314–327. doi: 10.1016/j.marpetgeo.2018.05.002. Fulltekst i vitenarkiv Vis sammendrag

  The statistics and dynamics of fractures formed during the accelerated maturation of kerogen-rich shale was investigated by heating Green River Shale (R-8 unit, Piceance Basin, northwestern Colorado) core samples while 3D X-ray microtomographic images were acquired. Previous studies have shown that, when there was no confining stress, fractures formed while the kerogen contained in the shale matured, and the produced hydrocarbon was expelled through these fractures. In the present study, X-ray tomographic scans at multiple voxel sizes were conducted on similar samples during heating. In one experiment, the shale sample was tightly fitted in a non-porous ceramic tube to confine it while it was heated. Three unconfined samples were heated and then held at different final temperatures to investigate the effects of the gas production rate on fracturing. 3D image processing was used to survey fracture network development, and time-lapse 2D digital image correlation analysis was used to monitor the development of the displacement and strain fields. The results revealed that fracturing is strongly dependent on the heating rate and the final heating temperature. While most of the fractures were oriented more-or-less parallel to the bedding plane, some were strongly inclined relative to the bedding plane. The formation of inclined fractures is attributed primarily to the shape and orientation of a minority of the flake-like kerogen patches, and also to the effective stress field and fractured zones of weakness. A conceptual model is proposed to explain the dynamics of fluid expulsion and the associate fracturing behavior.

• Gløersen, Øyvind Nøstdahl; Losnegard, Thomas Johansen; Malthe-Sørenssen, Anders; Dysthe, Dag Kristian & Gilgien, Matthias (2018). Propulsive Power in Cross-Country Skiing: Application and Limitations of a Novel Wearable Sensor-Based Method During Roller Skiing. Frontiers in Physiology. 9, s. 1–14. doi: 10.3389/fphys.2018.01631. Fulltekst i vitenarkiv Vis sammendrag

  Cross-country skiing is an endurance sport that requires extremely high maximal aerobic power. Due to downhill sections where the athletes can recover, skiersmust also have the ability to perform repeated efforts where metabolic power substantially exceeds maximal aerobic power. Since the duration of these supra-aerobic efforts is often in the order of seconds, heart rate, and pulmonary VO2 do not adequately reflect instantaneous metabolic power. Propulsive power (Pprop) is an alternative parameter that can be used to estimate metabolic power, but the validity of such calculations during cross-country skiing has rarely been addressed. The aim of this study was therefore twofold: to develop a procedure using small non-intrusive sensors attached to the athlete for estimating Pprop during roller-skiing and to evaluate its limits; and (2) to utilize this procedure to determine the Pprop generated by high-level skiers during a simulated distance race. Eight elite male cross-country skiers simulated a 15 km individual distance race on roller skis using ski skating techniques on a course (13.5 km) similar to World Cup skiing courses. Pprop was calculated using a combination of standalone and differential GNSS measurements and inertial measurement units. The method’s measurement error was assessed using a Monte Carlo simulation, sampling from the most relevant sources of error. Pprop decreased approximately linearly with skiing speed and acceleration, and was approximated by the equation Pprop(v, ˙v) = −0.54·v −0.71·˙v + 7.26 W·kg−1. Pprop was typically zero for skiing speeds >9 m·s−1, because the athletes transitioned to the tuck position. Peak Pprop was 8.35 ± 0.63 W·kg−1 and was typically attained during the final lap in the last major ascent, while average Pprop throughout the race was 3.35 ± 0.23 W·kg−1. The measurement error of Pprop increased with skiing speed, from 0.09 W·kg−1 at 2.0 m·s−1 to 0.58 W·kg−1 at 9.0 m·s−1. In summary, this study is the first to provide continuous measurements of Pprop for distance skiing, as well as the first to quantify the measurement error during roller skiing using the power balance principle. Therefore, these results provide novel insight into the pacing strategies employed by high-level skiers.

• Pluymakers, Anne Marie Henriette; Liu, J.; Kohler, Felix; Renard, Francois & Dysthe, Dag Kristian (2018). A high resolution interferometric method to measure local swelling due to CO2 exposure in coal and shale. International Journal of Coal Geology. ISSN 0166-5162. 187, s. 131–142. doi: 10.1016/j.coal.2018.01.007. Fulltekst i vitenarkiv
• Kohler, Felix; Gagliardi, Luca; Pierre-Louis, Olivier & Dysthe, Dag Kristian (2018). Cavity Formation in Confined Growing Crystals. Physical Review Letters. ISSN 0031-9007. 121(9), s. 1–5. doi: 10.1103/PhysRevLett.121.096101. Fulltekst i vitenarkiv Vis sammendrag

  Growing crystals form a cavity when placed against a wall. The birth of the cavity is observed both by optical microscopy of sodium chlorate crystals (NaClO3) growing in the vicinity of a glass surface, and in simulations with a thin film model. The cavity appears when growth cannot be maintained in the center of the contact region due to an insufficient supply of growth units through the liquid film between the crystal and the wall. We obtain a nonequilibrium morphology diagram characterizing the conditions under which a cavity appears. Cavity formation is a generic phenomenon at the origin of the formation of growth rims observed in many experiments, and is a source of complexity for the morphology of growing crystals in natural environments. Our results also provide restrictions for the conditions under which compact crystals can grow in confinement.

• Sanchez, Jesus Rodriguez; Zhang, Quing & Dysthe, Dag Kristian (2018). Microstructure and Relative Humidity Effects on Long-Term Indentation Creep Properties of Calcium Carbonate Cement. Preprints. ISSN 2310-287X. doi: 10.20944/preprints201810.0671.v1. Fulltekst i vitenarkiv
• Neuville, Amélie; Renaud, Louis; Luu, Thi Thuy; Minde, Mona Wetrhus; Jettestuen, Espen & Vinningland, Jan Ludvig [Vis alle 8 forfattere av denne artikkelen] (2017). Xurography for microfluidics on a reactive solid. Lab on a Chip. ISSN 1473-0197. 17(2), s. 293–303. doi: 10.1039/c6lc01253a. Fulltekst i vitenarkiv
• Li, Lei; Kohler, Felix; Røyne, Anja & Dysthe, Dag Kristian (2017). Growth of calcite in confinement. Crystals. 7(12). doi: 10.3390/cryst7120361. Fulltekst i vitenarkiv
• Høgberget, Jørgen; Røyne, Anja; Dysthe, Dag Kristian & Jettestuen, Espen (2016). Microscopic modeling of confined crystal growth and dissolution. Physical Review E (PRE). ISSN 2470-0045. 94(2). doi: 10.1103/PhysRevE.94.023005. Fulltekst i vitenarkiv
• Renard, Francois Marie Paul L; Cordonnier, Benoit; Dysthe, Dag Kristian; Boller, Elodie; Tafforeau, Paul & Rack, Alexander (2016). A deformation rig for synchrotron microtomography studies of geomaterials under conditions down to 10 km depth in the Earth. Journal of Synchrotron Radiation. ISSN 0909-0495. 23(4), s. 1030–1034. doi: 10.1107/S1600577516008730. Fulltekst i vitenarkiv
• Keszthelyi, Dániel; Dysthe, Dag Kristian & Jamtveit, Bjørn (2016). First principles model of carbonate compaction creep. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 121(5), s. 3348–3365. doi: 10.1002/2015JB012481. Fulltekst i vitenarkiv Vis sammendrag

  Rocks under compressional stress conditions are subject to long‐term creep deformation. From first principles we develop a simple micromechanical model of creep in rocks under compressional stress that combines microscopic fracturing and pressure solution. This model was then upscaled by a statistical mechanical approach to predict strain rate at core and reservoir scale. The model uses no fitting parameter and has few input parameters: effective stress, temperature, water saturation porosity, and material parameters. Material parameters are porosity, pore size distribution, Young's modulus, interfacial energy of wet calcite, the dissolution, and precipitation rates of calcite, and the diffusion rate of calcium carbonate, all of which are independently measurable without performing any type of deformation or creep test. Existing long‐term creep experiments were used to test the model which successfully predicts the magnitude of the resulting strain rate under very different effective stress, temperature, and water saturation conditions. The model was used to predict the observed compaction of a producing chalk reservoir.

• Keszthelyi, Dániel; Dysthe, Dag Kristian & Jamtveit, Bjørn (2016). Compaction of North-Sea Chalk by Pore-Failure and Pressure Solution in a Producing Reservoir. Frontiers in Physics. doi: 10.3389/fphy.2016.00004. Fulltekst i vitenarkiv
• Hafver, Andreas; Jettestuen, Espen; Kobchenko, Maya; Dysthe, Dag Kristian; Meakin, Paul & Malthe-Sørenssen, Anders (2014). Classification of fracture patterns by heterogeneity and topology. Europhysics letters. ISSN 0295-5075. 105(5). doi: 10.1209/0295-5075/105/56004. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Låstad, Silja Borring; Abbasova, Nigar; Combriat, Thomas Michel Daniel & Dysthe, Dag Kristian (2026). Three Dimensional Dynamics of Epithelial Monolayers. Fulltekst i vitenarkiv
• Låstad, Silja Borring; Abbasova, Nigar; Ho, Richard David Jun-Geet; Combriat, Thomas Michel Daniel & Dysthe, Dag Kristian (2025). Segmentation-free measurement of cell motion from quantitative phase imaging. Fulltekst i vitenarkiv
• Låstad, Silja Borring; Abbasova, Nigar; Combriat, Thomas Michel Daniel & Dysthe, Dag Kristian (2025). Cell height, area and volume fluctuations in MDCK monolayers. Fulltekst i vitenarkiv
• Vogt, Yngve; Krauss, Stefan Johannes Karl; Mossige, Joachim; Dysthe, Dag Kristian; Angheluta, Luiza & Jensenius, Alexander Refsum (2023). Bereder grunnen for kunstige organer. [Journal]. Apollon. Fulltekst i vitenarkiv
• Dziadkowiec, Joanna; Zareeipolgardani, Bahareh; Cheng, Hsiu-Wei; Dysthe, Dag Kristian; Røyne, Anja & Valtiner, Markus (2021). Forces between reactive surfaces. Fulltekst i vitenarkiv Vis sammendrag

  Adhesive and repulsive, nm-range surface forces acting between mineral grains control colloidal stability and mineral aggregation but less is known about how these forces are affected by surface reactivity and to what extent these grain-scale forces can influence various deformation processes in rocks. In this experimental work, we explore and quantify the surface forces acting between dynamic mineral surfaces that undergo recrystallization or are chemically reactive in contact with water or aqueous salt solutions. Our experimental setup consists of the surface forces apparatus (SFA) coupled with the multiple beam interferometry (MBI). This setup can excellently reproduce a typical grain contact geometry with nanometer-thin water films confined between contacting mineral grains over relatively large, micron-sized contact areas. Owing to the use of MBI, both surface growth or dissolution processes can be monitored during force measurements in real-time. As such, SFA can provide information about the links between surface reactivity and adhesive or repulsive surface forces. Using the examples of force measurements between recrystallizing or chemically reactive mineral surfaces such as carbonates, hydroxides, and silicates, we comment on the relationship between the measured surface forces and surface reactivity. We link our findings with the observed changes in mineral phases, surface topographies, or surface roughness. We also comment on how the micron-scale confinement in the SFA affects the growth and dissolution processes in contrast to less confined regions. The magnitude of the forces associated with dynamic mineral surfaces and the potential significance of these forces to macroscopic deformation processes and cohesion in rocks are discussed.

• Dziadkowiec, Joanna; Zareeipolgardani, Bahareh; Dysthe, Dag Kristian & Røyne, Anja (2020). Confined Nucleation of Calcium Carbonate Studied in the Surface Forces Apparatus. Fulltekst i vitenarkiv
• Dziadkowiec, Joanna; Zareeipolgardani, Bahareh; Bratvold, Jon E.; Nilsen, Ola; Dysthe, Dag Kristian & Røyne, Anja (2019). Long-range repulsive forces between reactive calcite surfaces are generated due to nucleation in a confined solution. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2019). Atomic scale view of crystallization in confinement Nucleation, step flow and transport limitation. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2019). Molecular layer resolution of crystal growth in nanoconfinement. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2019). Crystal growth in nanoconfinement. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2019). Molecular layer resolution of crystal growth in nanoconfinement. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2019). Simultaneous measurement of intracellular actin dynamics and strain field of the extracellular matrix. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2019). Calcium carbonate (re-)crystallization questions. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2019). Simultaneous measurement of intracellular actin dynamics and strain field of the extracellular matrix. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2019). Crystal growth in nanoconfinement. Fulltekst i vitenarkiv
• Ruiter, Lisa de; Austrheim, Håkon Olaf; Gunnæs, Anette Eleonora & Dysthe, Dag Kristian (2018). Quartz dissolution and M-S-H cement precipitation in a high pH ultramafic system. Fulltekst i vitenarkiv
• Ruiter, Lisa de; Austrheim, Håkon Olaf; Dysthe, Dag Kristian & Gunnæs, Anette Eleonora (2018). Quartz weathering associated with magnesium silicate hydrate cement precipitation. Fulltekst i vitenarkiv
• Ruiter, Lisa De; Austrheim, Håkon Olav & Dysthe, Dag Kristian (2017). Formation of magnesium silicate hydrate cement during lithification of ultramafic-rich glacial deposits. Fulltekst i vitenarkiv
• Ruiter, Lisa De; Austrheim, Håkon Olav & Dysthe, Dag Kristian (2017). Formation of magnesium silicate hydrate cement in the weathering zone of ultramafites. Fulltekst i vitenarkiv
• Sanchez, Jesus Rodriguez; Myszka, Barbara; Dysthe, Dag Kristian & Boccaccini, Aldo (2017). Biomineralization study of calcium carbonate cements. Fulltekst i vitenarkiv
• Sanchez, Jesus Rodriguez; Liberto, Teresa; Zhang, Qing; Barentine, Catherine & Dysthe, Dag Kristian (2017). Rheological and long-term indentation creep properties of calcium carbonate cements. Fulltekst i vitenarkiv
• Sanchez, Jesus Rodriguez; Liberto, Teresa; Zhang, Qing; Barentine, Catherine & Dysthe, Dag Kristian (2017). Lab meeting: Rheological and long-term indentation creep properties of calcium carbonate cements. Fulltekst i vitenarkiv
• Neuville, Amélie; Renaud, Louis; Minde, Mona Wetrhus; Vinningland, Jan Ludvig; Hiorth, Aksel & Dysthe, Dag Kristian (2017). Can we get a better knowledge on dissolution processes in chalk by using microfluidic chips? Fulltekst i vitenarkiv
• Ruiter, Lisa De; Austrheim, Håkon Olav & Dysthe, Dag Kristian (2016). The lithification of ultramafic dominated till with magnesium silicate hydrate: a new green concrete. Fulltekst i vitenarkiv
• Sanchez, Jesus Rodriguez; Cordonnier, Benoit; Renard, Francois & Dysthe, Dag Kristian (2016). Transition between brittle and ductile behaviour on carbonate rocks: an X-ray tomographic analysis. Fulltekst i vitenarkiv
• Sanchez, Jesus Rodriguez & Dysthe, Dag Kristian (2016). Synthesis of calcium carbonate particles via continuous flow microfluidics. Fulltekst i vitenarkiv
• Sanchez, Jesus Rodriguez & Dysthe, Dag Kristian (2016). A tour around research in the Depart. of Physics. First stop" NanoHeal: Nano-tailoring organo-mineral materials". Fulltekst i vitenarkiv
• Neuville, Amélie & Dysthe, Dag Kristian (2016). JCR meeting for the Pore2Core project, experimental part. Fulltekst i vitenarkiv
• Høgberget, Jørgen; Kohler, Felix; Røyne, Anja; Jettestuen, Espen & Dysthe, Dag Kristian (2016). Combining in situ Interferometry and Kinetic Monte Carlo to Study Mechanisms of Nanoconfined Crystallization. Fulltekst i vitenarkiv
• Neuville, Amélie; Luu, Thi Thuy & Dysthe, Dag Kristian (2016). Chalk-calcite-microfluidic experiments: construction and flooding of microsystems with reactive fluids. Fulltekst i vitenarkiv
• Neuville, Amelie; Renaud, Louis; Luu, Thi Thuy; Vinningland, Jan Ludvig; Jettestuen, Espen & Dysthe, Dag Kristian [Vis alle 7 forfattere av denne artikkelen] (2016). Xurography for microfluidics in reactive systems: the example of the calcite dissolution. Fulltekst i vitenarkiv
• Neuville, Amélie; Renaud, Louis; Luu, Thi Thuy; Jettestuen, Espen; Vinningland, Jan Ludvig & Hiorth, Aksel [Vis alle 7 forfattere av denne artikkelen] (2016). Can we get more knowledge on solid dissolution processes using microfluidic chips? Fulltekst i vitenarkiv
• Skattum, Sigve Bøe; Bergsaker, Anne Schad & Dysthe, Dag Kristian (2015). CO2 Storage in North Sea Chalk Fields. Fulltekst i vitenarkiv
• Kohler, Felix & Dysthe, Dag Kristian (2015). Nanoconfined Crystal Growth investigated by Reflection Interference Contrast Microscopy. Fulltekst i vitenarkiv
• Neuville, Amélie; Vinningland, Jan Ludvig; Luu, Thi Thuy; Jettestuen, Espen; Dysthe, Dag Kristian & Hiorth, Aksel (2015). Chalk-calcite-microfluidic experiments: construction and flooding of microsystems with reactive fluids, oral presentation. Fulltekst i vitenarkiv
• Neuville, Amélie; Vinningland, Jan Ludvig; Luu, Thi Thuy; Jettestuen, Espen; Dysthe, Dag Kristian & Hiorth, Aksel (2015). Chalk-calcite-microfluidic experiments: construction and flooding of microsystems with reactive fluids. Fulltekst i vitenarkiv
• Keszthelyi, Dániel; Dysthe, Dag Kristian & Jamtveit, Bjørn (2015). Compaction of North Sea Chalk - A new micromechanical mechanism of pore collapse and a statistical mechanical upscaling to predict Ekofisk subsidence. Fulltekst i vitenarkiv
• Keszthelyi, Dániel; Jamtveit, Bjørn & Dysthe, Dag Kristian (2015). Compaction creep of carbonate rocks. Fulltekst i vitenarkiv
• Keszthelyi, Dániel; Dysthe, Dag Kristian & Jamtveit, Bjørn (2015). The mysterious subsidence of the seafloor due to oil production – How to predict it with a simple model? EGU Blogs. Fulltekst i vitenarkiv
• Høgberget, Jørgen; Røyne, Anja; Dysthe, Dag Kristian & Jettestuen, Espen (2015). Confined Crystal Growth and Dissolution. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian & Austrheim, Håkon Olav (2015). Beyond research based teaching: Teaching interdisciplinary research and pushing students beyond their training. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2015). CO2 for EOR and storage in North sea chalk fields? Fulltekst i vitenarkiv
• Dysthe, Dag Kristian & Austrheim, Håkon Olav (2015). Beyond research based teaching: Teaching interdisciplinary research and pushing students beyond their training. Fulltekst i vitenarkiv
• Keszthelyi, Dániel; Dysthe, Dag Kristian & Jamtveit, Bjørn (2015). Model of compaction in carbonates. Fulltekst i vitenarkiv
• Keszthelyi, Dániel; Jamtveit, Bjørn & Dysthe, Dag Kristian (2015). A model of compaction creep in carbonates. Fulltekst i vitenarkiv
• Keszthelyi, Dániel; Jamtveit, Bjørn & Dysthe, Dag Kristian (2015). Compaction creep by pore failure and pressure solution applied to a carbonate reservoir. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian; Neuville, Amélie; Luu, Thi Thuy; Kohler, Felix & Li, Lei (2015). Microfluidic Tools for Reactive Transport In Porous Media. Fulltekst i vitenarkiv
• Keszthelyi, Dániel; Dysthe, Dag Kristian & Jamtveit, Bjørn (2015). Compaction of the Ekofisk oil reservoir - On small- and on large-scale. Fulltekst i vitenarkiv
• Keszthelyi, Dániel; Dysthe, Dag Kristian & Jamtveit, Bjørn (2015). Compaction of North-sea chalk by pore-failure and pressure solution. Fulltekst i vitenarkiv
• Keszthelyi, Dániel; Dysthe, Dag Kristian & Jamtveit, Bjørn (2015). A simple model of compaction in carbonates. Fulltekst i vitenarkiv
• Neuville, Amelie; Vinningland, Jan Ludvig; Luu, Thi Thuy; Jettestuen, Espen; Dysthe, Dag Kristian & Hiorth, Aksel (2015). Microfluidic experiments: construction and flooding of microsystems with reactive fluids. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian; Vinningland, Jan Ludvig & Neuville, Amélie (2015). Microfluidic tools for reactive transport in porous media. Fulltekst i vitenarkiv
• Neuville, Amélie; Dysthe, Dag Kristian; Hiorth, Aksel & Li, Lei (2014). Flooding microsystems with reactive fluids Calcite-Chalk microfluidic. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian; Hiorth, Aksel; Neuville, Amélie; Vinningland, Jan Ludvig; Jettestuen, Espen & Skartlien, Roar (2014). Reactive flow during water flooding -from pore2core. Fulltekst i vitenarkiv
• Neuville, Amélie; Dysthe, Dag Kristian & Hiorth, Aksel (2014). Flooding microsystems with reactive fluids Calcite-Chalk-microfluidic. Fulltekst i vitenarkiv
• Vinningland, Jan Ludvig; Neuville, Amelie; Pedersen, Janne; Jettestuen, Espen; Dysthe, Dag Kristian & Hiorth, Aksel (2014). Reactive flow simulations: one-to-one comparison with experiments. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian & Read, Alexander Lincoln (2014). Beregninger i kurset FYS2150 "Eksperimentell fysikk". Fulltekst i vitenarkiv
• Høgberget, Jørgen; Røyne, Anja; Malthe-Sørenssen, Anders; Dysthe, Dag Kristian & Jettestuen, Espen (2014). Nanoconfined Crystal Growth and Dissolution. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2014). The different roles of experiments. Fulltekst i vitenarkiv
• Dysthe, Dag Kristian (2014). Microfluidic experiments - real time reactions. Fulltekst i vitenarkiv
• Schöb, Franziska Jessica; Dysthe, Dag Kristian; Scholz, Hanne; Binder, Alexander & Malthe-Sørenssen, Anders (2026). From Pixels to Phenotypes: Deep Learning on Label-Free Microscopy Data for Cell Fate Prediction How Algorithms Help Us See More. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  In this thesis, we used supervised deep learning on label-free microscopy data to predict cell fate and state from purely visual information, without relying on fluorescent labeling or manual segmentation. Across three studies, we combined phase-contrast and holotomographic imaging with convolutional neural networks to tackle problems that are central to stem cell biology and cancer research: predicting the differentiation efficiency of induced pluripotent stem cell clones, identifying germ-layer lineages in differentiating cultures, and detecting macrophage-induced cancer cell death. By building segmentation-free pipelines that operated directly on image patches, we reduced the need for explicit cell masks and made our methods easier to deploy in realistic, noisy experimental settings. The overarching results showed that biological label-free images contained sufficient morphological information for deep networks to recover biologically meaningful patterns, but also revealed clear limits to what static morphology could predict. In stem cell differentiation, our models already distinguished high- from lowefficiency clones early in the protocol, and learned image cues that matched intuitive notions of colony coverage and uniformity. In germlayer prediction, endpoint-trained models decoded lineage identity from holotomographic morphology and reconstructed a plausible timeline of lineage divergence when applied retrospectively, while struggling more in mixed cultures with overlapping lineages. In the cancer cell death study, deep learning distinguished dying from alive cells at the time of death, yet early prediction beyond a short pre-death window remained difficult, indicating that death morphology emerged abruptly rather than gradually over many hours. Together, these findings support the view that deep learning on label-free microscopy could provide non-destructive, scalable readouts of cell fate, while emphasizing the need for time-aware models, richer training labels, and improved domain generalization to fully exploit biological label-free imaging in biomedical workflows.

• Neuville, Amélie; Vinningland, Jan Ludvig; Luu, Thi Thuy; Dysthe, Dag Kristian; Jettestuen, Espen & Hiorth, Aksel (2015). Reactive flow during water flooding – from pore to core Half-year progress report 2015. JCR. Fulltekst i vitenarkiv
• Hiorth, Aksel; Dysthe, Dag Kristian; Neuville, Amélie; Vinningland, Jan Ludvig & Jettestuen, Espen (2014). Reactive flow during water flooding – from pore to core, Quartely report 2, 2014. Join Chalk Research. Fulltekst i vitenarkiv
• Neuville, Amélie; Vinningland, Jan Ludvig; Jettestuen, Espen; Skartlien, Roar; Dysthe, Dag Kristian & Hiorth, Aksel (2014). JCR-7 Symposium 2014 Transaction - Reactive flow during water flooding – from pore2core. Join Chalk Research. Fulltekst i vitenarkiv

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