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- Creator:
- Aksoy, Doruk and Kim, Donghak
- Description:
- This dataset contains snapshots from simulations of a hexagonal self oscillating gel sheet defined via a triangular lattice. The lattice has stretching springs between neighboring vertices and bending springs with energy proportional to the square of the angle between neighboring traingular faces. The motion of the lattice is driven by time- and space-varying distributions of the rest lengths of the stretching springs. In the motivating experiments on thin gel sheets, there are chemical waves, radial or spiral in form, that induce local swelling of the sheets. As a simple model, this dataset considers radial or planar (unidirectional) traveling waves in the simulations. The sheet is modeled as a flat hexagon of radius 1 with an equilateral triangular triangle lattice mesh, with initially uniform mesh spacing of 1/33, resulting in 3367 mesh points. A small out-of-plane perturbation is applied and the motion evolves over the sheet over time. The sheet is modeled to have damped dynamics. However for large enough wave amplitudes, the sheet rapidly buckles into shapes with time-varying distributions of curvature, large in magnitude. For more information on the simulation that generated the data, please refer to "Semi-implicit methods for the dynamics of elastic sheets,” at Journal of Computational Physics by Alben et al. For an example SciML application that considers this dataset, please refer to "Inverse design of self-oscillatory gels through deep learning." Neural Computing and Applications by Aksoy et al.
- Keyword:
- Soft robotics, Partial Differential Equations, Scientific Simulations, and Chaotic Systems
- Citation to related publication:
- Alben, Silas, et al. "Semi-implicit methods for the dynamics of elastic sheets." Journal of Computational Physics 399 (2019): 108952., Aksoy, Doruk, et al. "Inverse design of self-oscillatory gels through deep learning." Neural Computing and Applications 34.9 (2022): 6879-6905., Aksoy, Doruk, et al. "An incremental tensor train decomposition algorithm." SIAM Journal on Scientific Computing 46.2 (2024): A1047-A1075., and Aksoy, Doruk, and Alex A. Gorodetsky. "Incremental Hierarchical Tucker Decomposition." arXiv preprint arXiv:2412.16544 (2024).
- Discipline:
- Engineering and Science
-
- Creator:
- Beletsky, Dmitry, Beletsky, R, and Rowe, M
- Description:
- Reliable prediction of hypoxic events in the coastal ocean and lakes depends to a large degree on the ability of hydrodynamic models to accurately simulate nearshore circulation and thermal structure. With focus on the hypoxia-prone south shore of Lake Erie, temperature and currents were measured in the central basin in 2017-2019. Major upwelling events along the south shore were identified and linked with occurrence of strong, sustained wind from the northeast (NE). A three-dimensional FVCOM-based hydrodynamic model was able to predict upwelling events along the south shore reasonably well but the surface mixed layer and thermocline depth were shallower than in observations. It was found that basin-scale wind stress curl (WSC) transformed canonic two-gyre circulation in the uniform NE wind case into a single gyre circulation causing both alongshore and cross-shore current reversal that modified coastal upwelling/downwelling. Observational evidence of Kelvin waves on the south shore was found for the first time. Kelvin wave speed in the model was underestimated. Model runs with enhanced vertical mixing improved predictions of mixed layer and thermocline depth and near-bottom dissolved oxygen but also caused additional diffusion of thermocline.
- Discipline:
- Science
-
- Creator:
- Ludlow, Andrew
- Description:
- Single molecule long read RNA/cDNA sequencing of TERT revealed 45 TERT mRNA variants including 13 known and 32 novel variants. Among the variants, TERT Delta 2-4, which lacks exons 2-4 but retains the original open reading frame, was selected for further study. Induced pluripotent stem cells and cancer cells express higher levels of TERT Delta 2-4 compared to primary human bronchial epithelial cells. Overexpression of TERT Delta 2-4 enhanced clonogenicity and resistance to cisplatin-induced apoptosis. Knockdown of endogenous TERT Delta 2-4 in Calu-6 cells reduced clonogenicity and resistance to cisplatin. Our results suggest that TERT Delta 2-4 enhances cancer cells’ resistance to intrinsic apoptosis. RNA sequencing following knockdown of Delta 2-4 TERT indicates that translation is downregulated and that mitochondrial related proteins are upregulated compared to controls.
- Keyword:
- TERT, Alternative splicing, Telomere, and Telomerase
- Citation to related publication:
- Kim, J.J., Ahn, A., Ying, J.Y. et al. Discovery and characterization of a novel telomerase alternative splicing isoform that protects lung cancer cells from chemotherapy induced cell death. Sci Rep 15, 6787 (2025). https://doi.org/10.1038/s41598-025-90639-3
- Discipline:
- Science
-
- Creator:
- Ludlow, Andrew and Kim, Jeongjin
- Description:
- Part of the regulation of telomerase activity includes the alternative splicing (AS) of the catalytic subunit telomerase reverse transcriptase (TERT). Although a therapeutic window for telomerase/TERT inhibition exists between cancer cells and somatic cells, stem cells express TERT and rely on telomerase activity for physiological replacement of cells. Therefore, identifying differences in TERT regulation between stem cells and cancer cells is essential for developing telomerase inhibition-based cancer therapies that reduce damage to stem cells. In this study, we measured TERT splice variant expression and telomerase activity in induced pluripotent stem cells (iPSCs), neural progenitor cells (NPCs), and non-small cell lung cancer cells (NSCLC, Calu-6 cells). We observed that a NOVA1-PTBP1-PTBP2 axis regulates TERT alternative splicing (AS) in iPSCs and their differentiation into NPCs. We also found that splice-switching of TERT, which regulates telomerase activity, is induced by different cell densities in stem cells but not cancer cells. Lastly, we identified cell type-specific splicing factors that regulate TERT AS. Overall, our findings represent an important step forward in understanding the regulation of TERT AS in stem cells and cancer cells. These data and subsequent studies may reveal a splicing factor(s) or their binding site(s) that could be targeted with small molecule drugs or antisense oligonucleotides, respectively, to reduce telomerase activity in cancer cells and promote durable cancer remissions.
- Keyword:
- Telomere, telomerase, TERT, alternative RNA splicing
- Citation to related publication:
- Kim JJ, Sayed ME, Ahn A, Slusher AL, Ying JY, et al. (2023) Dynamics of TERT regulation via alternative splicing in stem cells and cancer cells. PLOS ONE 18(8): e0289327. https://doi.org/10.1371/journal.pone.0289327
- Discipline:
- Science
-
Great Lakes Historical Ice Dynamics
User Collection
- Creator:
- King, Katelyn B., Fujisaki-Manome, Ayumi, Brant, Cory, and Alofs, Karen
- Description:
- This collection includes raster layers (as a geodatabase) with ice metrics for each of the Great Lakes representing the historical time period of 1898-1960. One metric is spatial mean ice duration (the number of days per year when the lake was frozen) and the other is coefficient of variation of ice duration (variability across years).
- Keyword:
- Great Lakes, Ice , Ice duration, Ice variability, Historical , Huron, Ontario, Erie, Michigan, and Superior
- Discipline:
- Science
1Works -
- Creator:
- Howard, Cecilia M. and Sheldon, Nathan D.
- Description:
- This study uses a compilation of microbialite occurrences in the Archean and Paleoproterozoic from the literature to investigate how depositional environment changed across environmental shifts such as the Great Oxidation Event and the Huronian Glaciations. Key Points: - We compiled microbialite occurrences from the Archean and Paleoproterozoic with broad depositional environment information, which has not previously been incorporated in larger compilations of occurrences. - Tidal and other terrestrially-influenced settings comprise the majority of the early microbialite record, even across major environmental shifts and Abstract: Changes in microbialite abundance during the Archean and Paleoproterozoic have been attributed to a variety of environmental and biological factors. Past work looking at large-scale patterns of microbialite abundance generally assumes shallow marine deposition rather than incorporating specific settings, however, there is significant variance in conditions that might impact microbialite formation and preservation between marine, tidal, and terrestrial environments. We compiled microbialite occurrences from the Archean and Paleoproterozoic with integrated depositional environment information in order to assess how microbialite development and preservation changed across different settings. Microbially induced sedimentary structures formed a significant part of the record, but their identification primarily in conjunction with stromatolites rather than independently suggests that they may be undercounted. Broad trends in abundance were similar to previous compilations, but critically, we found that the majority of microbialites from this period formed in tidal environments. The proportion of terrestrially-influenced (including tidal) microbialites increased during periods of craton development in the Neoarchean and mid-Paleoproterozoic, with increases in marine microbialite abundance trailing. Tidal microbialite abundance also recovered more quickly than marine abundance following the Great Oxidation Event and Huronian Glaciations.
- Keyword:
- Microbialite, Stromatolite, Archean, Paleoproterozoic, Geosciences, and Tidal
- Citation to related publication:
- Howard, C.M. (2025). Unraveling Records of Time and Environment in Microbial Ecosystems from the Archean to Today (Ph.D. Dissertation). University of Michigan. and Howard, C.M. and Sheldon, N.D. (in prep). Chapter 2 Microbialite Niches across the Archean and Paleoproterozoic.
- Discipline:
- Science
-
- Creator:
- King, Katelyn, Schell, Justin, Alofs, Karen, Thomer, Andrea, Wehrly, Kevin, Lenard, Michael , and Lopez-Fernandez, Hernan
- Description:
- Michigan lakes are an important resource, however, their ecosystems are declining and projected to continue to face further impacts under future land use and climate change. Understanding how lake ecosystems respond to environmental stressors and management actions is critical for identifying resilient lakes and developing adaptation strategies. However, the ability to manage lakes is hampered by a lack of historical information. Historical lake data in Michigan were originally archived as index cards at the Michigan Department of Natural Resources. All of the images of these cards are stored in this collection, Collections, Heterogeneous data, and Next Generation Ecological Studies (CHANGES) - Michigan Lake Surveys, and the images for this specific dataset are stored in the CHANGES Project- Fish Growth Analysis (GROW) dataset. The CHANGES project used a crowd sourcing platform called Zooniverse to transcribe at least basic information (i.e. dates, collected by) from all of these cards. Some of the card types, such as the one in this dataset, were prioritized to transcribe to produce a usable (i.e. machine-readable, uniform, and standardized) historical dataset. and Fish growth cards document fish that were aged and measured during fish surveys. The data that were transcribed from these cards and included in this dataset (grow_data.csv) are for each fish species: the number of fish measured in each age group, and the minimum, maximum, and average length of the fish for each age group. The final growth dataset includes length-at-age information for 36 different species (grow_species_table). For a description of all fields of this data table see grow_datadictionary.
- Keyword:
- fish, lake, growth, length, and Michigan
- Citation to related publication:
- King, K.B.S., Schell, J, Wehrly, K.E., Lenard, M., Singer, R., López-Fernández, H., Thomer, A.K., & Alofs, K.M. Community science helps digitize 78 years of fish and habitat data for thousands of lakes in Michigan, USA. under review and Grabda, E.E., Flood, P.J., King, K.B.S., Breck, J.E., Wehrly, K.E., and Alofs, K.M. 2025. Mismatch between climate-based bioenergetics model of fish growth and long-term and regional-scale empirical data. Canadian Journal of Fisheries and Aquatic Sciences. 82: 1-15. https://doi.org/10.1139/cjfas-2024-0266
- Discipline:
- Science
-
- Creator:
- King, Katelyn , Schell, Justin, Alofs, Karen, Thomer, Andrea, Wehrly, Kevin, Lenard, Michael , and Lopez-Fernandez, Hernan
- Description:
- Michigan lakes are an important resource, however, their ecosystems are declining and projected to continue to face further impacts under future land use and climate change. Understanding how lake ecosystems respond to environmental stressors and management actions is critical for identifying resilient lakes and developing adaptation strategies. However, the ability to manage lakes is hampered by a lack of historical information. Historical lake data in Michigan were originally archived as index cards at the Michigan Department of Natural Resources. All of the images of these cards are stored in this collection, Collections, Heterogeneous data, and Next Generation Ecological Studies (CHANGES) - Michigan Lake Surveys, and the images for this specific dataset are stored in the CHANGES Project- Lake Summary (SUMM) dataset. The CHANGES project used a crowd sourcing platform called Zooniverse to transcribe at least basic information (i.e. dates, collected by) from all of these cards. Some of the card types, such as the one in this dataset, were prioritized to transcribe to produce a usable (i.e. machine-readable, uniform, and standardized) historical dataset. and Lake summary cards that we transcribed and curated include habitat information for a lake as well as observed fish species (summ_data.csv). These variables include anthropogenic lake characteristics such as fishing intensity, shoreline structures, and dams; lake morphometric characteristics like depth and area; as well as in situ measures of temperature, dissolved oxygen, and Secchi depth. Many of the characteristics were listed as a range, and therefore, have a column for minimum and maximum in the data file (e.g. temp_surface_min_c and temp_surface_max_c). In addition, the lake summary cards listed the fish species present, so the csv file includes columns with the fish species common name (summ_species_table) and corresponding values are either a ‘1’ representing presence of a species or ‘0’ representing absence. For a full description of all the fields of this data table see summ_datadictionary.
- Keyword:
- lake, fish, Secchi, temperature, nutrients, oxygen, shoreline, habitat, dams, lake depth, lake area, and fishing intensity
- Citation to related publication:
- King, K.B.S., Schell, J, Wehrly, K.E., Lenard, M., Singer, R., López-Fernández, H., Thomer, A.K., & Alofs, K.M. Community science helps digitize 78 years of fish and habitat data for thousands of lakes in Michigan, USA. under review
- Discipline:
- Science
-
- Creator:
- King, Katelyn, Schell, Justin, Alofs, Karen, Thomer, Andrea, Wehrly, Kevin, Lenard, Michael, and Lopez-Fernandez, Hernan
- Description:
- Michigan lakes are an important resource, however, their ecosystems are declining and projected to continue to face further impacts under future land use and climate change. Understanding how lake ecosystems respond to environmental stressors and management actions is critical for identifying resilient lakes and developing adaptation strategies. However, the ability to manage lakes is hampered by a lack of historical information. Historical lake data in Michigan were originally archived as index cards at the Michigan Department of Natural Resources. All of the images of these cards are stored in this collection, Collections, Heterogeneous data, and Next Generation Ecological Studies (CHANGES) - Michigan Lake Surveys, and the images for this specific dataset are stored in the CHANGES Project- Fish Collection (FISHc) dataset. The CHANGES project used a crowd sourcing platform called Zooniverse to transcribe at least basic information (i.e. dates, collected by) from all of these cards. Some of the card types, such as the one in this dataset, were prioritized to transcribe to produce a usable (i.e. machine-readable, uniform, and standardized) historical dataset. and Fish collection card types include targeted and non-targeted fisheries surveys by the Department of Natural Resources and this information was transcribed and curated into a csv file (fishc_data.csv). These records include information on the gear types used, the area surveyed and the length and mesh size of nets fished. The number and common name of fish species caught were recorded as well and included in a species table (fishc_species_table). A description of all data fields can be found in the fishc_datadictionary.
- Keyword:
- lake , fish, gear, abundance, and Michigan
- Citation to related publication:
- King, K.B.S., Schell, J, Wehrly, K.E., Lenard, M., Singer, R., López-Fernández, H., Thomer, A.K., & Alofs, K.M. Community science helps digitize 78 years of fish and habitat data for thousands of lakes in Michigan, USA. under review and King, K.B.S, Giacomini, H.C., Wehrly, K., López-Fernández, H., Thomer, A.K., & Alofs, K.M. (2023). Using historical fish catch data to evaluate predicted changes in relative abundance in response to a warming climate. Ecography. 2023:8. https://doi.org/10.1111/ecog.06798
- Discipline:
- Science
-
- Creator:
- Sutton, Etienne, Snapp, Sieglinde, Morrone, Vicki, and Blesh, Jennifer
- Description:
- Cover crops support ecosystem services in agroecosystems, but their performance can be highly variable. Functional trait ecology provides a useful framework for understanding variation in cover crop performance across different growing conditions. However, trait variation within species remains understudied compared to variation between species. In a two-year experiment, we measured nine functional traits for three cover crop species across 13 fields on working farms that spanned a gradient of soil health. Each field contained three cover crop treatments: a functionally diverse mixture of cereal rye (Secale cereale), crimson clover (Trifolium incarnatum), and dwarf-essex rapeseed (Brassica napus), and rye and clover monocrops. We evaluated i) the magnitude and relative importance of intraspecific and interspecific trait variation; ii) which soil health indicators best explained trait variation; and iii) whether interspecific interactions in mixture induced trait plasticity. Despite strong trait contrasts between species, intraspecific trait variation comprised 50% of total trait variation, on average. Trait variation was best explained by particulate organic matter nitrogen (POM N), soil phosphorus, pH, and permanganate oxidizable carbon for clover; by POM N and soil phosphorus for rye; and by POM N for dwarf essex. Rye and clover also showed significant trait plasticity in mixture relative to monocrop treatments. Our study demonstrates that intraspecific and interspecific trait variation are equally important, and that examining trait variation within species can improve the ability to predict cover crop outcomes. This information can inform cropping system design in distinct contexts to promote success of component species and complementary ecosystem functions.
- Keyword:
- cover crop, functional trait, soil health, mixture, species interactions, and intraspecific trait variation
- Citation to related publication:
- Sutton, E., Snapp, S., Morrone, V., & Blesh, J. (2025). Cover crop functional trait plasticity in response to soil conditions and interspecific interactions. Plant and Soil. https://doi.org/10.1007/s11104-025-07471-x
- Discipline:
- Science
-
- Creator:
- Quartey, Nii-Boi A and Liemohn, Michael W
- Description:
- This dataset contains results from the BATS-R-US multispecies MHD code simulating the solar wind interaction at Mars at the following orbital and solar cycle locations: solar maximum at perihelion, solar maximum at aphelion, solar minimum at perihelion, solar minimum at aphelion. These simulations contain results with and without the crustal magnetic fields and includes variables such as the magnetic field and ion density., 2025-02-25: The metadata in this dataset has been updated in response to reviewer comments during the journal review process. Additional Tecplot 360 EX file containing MAVEN multifluid MHD simulation data added. The multifluid MHD simulation result from this result is from the MAVEN simulation library. The simulation result is run for 25,000 iterations., and 2025-04-28: The following files have been replaced with the following as these files contain the nominal solar wind conditions: z_0_mhd_permax.plt -> permax_3d.plt z_0_mhd_aphmax.plt -> aphmax_3d.plt z_0_mhd_permin.plt -> permin_3d.plt z_0_mhd_aphmin.plt -> aphmin_3d.plt The following file has been removed as the slice can be extracted from permax_3d.plt: x_0_mhd_permax.plt
- Keyword:
- mars, magnetosphere, magnetotail, current sheet, asymmetry, multispecies, multifluid, MHD, and MAVEN
- Citation to related publication:
- https://doi.org/10.1029/2024JA033445
- Discipline:
- Science
-
- Creator:
- Nunley, Hayden, Xue, Xufeng, Sun, Yubing, Resto-Irizarry, Agnes M, Yuan, Ye, Yong, Koh Meng Aw, Zheng, Yi, Weng, Shinuo, Shao, Yue, Lubensky, David K, Studer, Lorenz, and Fu, Jianping
- Description:
- Studies of fate patterning during development typically emphasize cell-cell communication via diffusible chemical signals. Recent experiments on stem cell colonies (see Xue et al. Nature Materials 2018), however, suggest that in some cases mechanical stresses, rather than secreted chemicals, enable long-ranged cell-cell interactions that specify positional information and pattern cell fates. The authors of this earlier publication reported a set of in vitro experiments in which uniformly supplied chemical media induced spatially patterned fates in cell colony in a disc geometry. They provided significant evidence that inter-cellular mechanical interactions, as well as mechanical interactions between cells and the substrate, play an important role in this in vitro differentiation process. As part of these experiments, they showed that the concentric width of the outer fate domain is approximately constant as the colony diameter is increased from 300 um to 800 um. In this subsequent publication, we propose a mathematical model for this fate patterning process and explore how the fate pattern depends on substrate stiffness. The experimental images of cell colonies, both for varying cell colony diameter (from Xue et al. Nature Materials 2018) and for varying substrate stiffness (data generated for the publication linked to these data), are provided here. Each example has an image for PAX3 signal (marker for outer fate domain; Paired box gene 3) and an image for DAPI signal (staining nuclei; 4′,6-diamidino-2-phenylindole).
- Keyword:
- Biomechanics, Cell communication, Cell mechanics, Developmental pattern formation, Force sensing, and Vertebrate development
- Citation to related publication:
- Nunley H, Xue X, Fu, J, Lubensky, DK. Generation of fate patterns via intercellular forces. BioRxiv 442205 [Preprint]. April 30, 2021 [cited 2025 Feb 20]. Available from: doi: https://doi.org/10.1101/2021.04.30.442205 and Xue X, Sun Y, Resto-Irizarry A.M. et al. Mechanics-guided embryonic patterning of neuroectoderm tissue from human pluripotent stem cells. Nature Mater 17, 633–641 (2018). https://doi.org/10.1038/s41563-018-0082-9
- Discipline:
- Science and Engineering
-
- Creator:
- Nunley, Hayden and Lubensky, David K
- Description:
- In a previous study (Xue et al. Nature Materials 2018), the authors showed that a key fate patterning event in vertebrate development can be reproduced in an in vitro stem cell culture. They further showed that this in vitro fate pattern seems to depend on mechanical signals rather than secreted chemical signals. In this follow-up study, a mathematical model of this process is proposed. The code in this deposit is for the simulation of this mathematical model in various cell layer geometries and substrate geometries. These geometries include a 1D cell layer, quasi-1D stripe geometry, disc geometry (all on a very thin substrate or a substrate composed of microposts) as well as a 1D cell layer on a finite-thickness substrate. Our model implies that the width of the outer fate domain varies non-monotonically with substrate stiffness, a prediction that we confirm experimentally.
- Keyword:
- Biomechanics, Cell communication, Cell mechanics, Developmental pattern formation, and Force sensing
- Citation to related publication:
- Nunley H, Xue X, Fu, J, Lubensky, DK. Generation of fate patterns via intercellular forces. BioRxiv 442205 [Preprint]. April 30, 2021 [cited 2025 Feb 20]. Available from: doi: https://doi.org/10.1101/2021.04.30.442205, Xue X, Sun Y, Resto-Irizarry A.M. et al. Mechanics-guided embryonic patterning of neuroectoderm tissue from human pluripotent stem cells. Nature Mater 17, 633–641 (2018). https://doi.org/10.1038/s41563-018-0082-9, Banerjee S, Marchetti MC. Substrate rigidity deforms and polarizes active gels. EPL (Europhysics Letters) 96, 28003 (2011). https://doi.org/10.1209/0295-5075/96/28003, Edwards CM, Schwarz US. Force Localization in Contracting Cell Layers, Physical Review Letters 107, 128101 (2011). https://doi.org/10.1103/PhysRevLett.107.128101, and Banerjee S, Marchetti MC. Contractile Stresses in Cohesive Cell Layers on Finite-Thickness Substrates, Physical Review Letters 109, 108101 (2012). https://doi.org/10.1103/PhysRevLett.109.108101
- Discipline:
- Engineering and Science
-
- Creator:
- Nunley, Hayden, Xue, Xufeng, Sun, Yubing, Resto-Irizarry, Agnes M, Yuan, Ye, Yong, Koh Meng Aw, Zheng, Yi, Weng, Shinuo, Shao, Yue, Lubensky, David K, Studer, Lorenz, and Fu, Jianping
- Description:
- In an earlier study (Xue et al. Nature Materials 2018), stem cells differentiated into one of two cell types, neural plate border (NPB) or neural plate (NP), in vitro. This previous study demonstrated that this differentiation is likely mechanics-guided. Part of this demonstration was measurements of the displacement of microposts under the cell layer as the cells differentiate. These measurements suggested that the NPB cells are more contractile than NP cells. In a follow-up study (linked to this dataset), we quantitatively analyzed these data to demonstrate even further that the NPB cells are mechanically different than the NP cells and that the post displacement profile is not explained by a model of a cell layer with uniform mechanical properties. This analysis motivated the mathematical model -- for this cell colony system -- that we proposed and analyzed.
- Keyword:
- Biomechanics, Cell communication, Cell mechanics, Developmental pattern formation, Force sensing, and Vertebrate development
- Citation to related publication:
- Hayden Nunley, Xufeng Xue, Jianping Fu, David K. Lubensky bioRxiv 2021.04.30.442205; doi: https://doi.org/10.1101/2021.04.30.442205 and Xue X, Sun Y, Resto-Irizarry A.M. et al. Mechanics-guided embryonic patterning of neuroectoderm tissue from human pluripotent stem cells. Nature Mater 17, 633–641 (2018). https://doi.org/10.1038/s41563-018-0082-9
- Discipline:
- Engineering and Science
-
- Creator:
- Nunley, Hayden, Xue, Xufeng, Fu, Jianping, and Lubensky, David K
- Description:
- In an earlier publication (Xue et al. Nature Materials 2018), the authors reported a set of in vitro experiments in which uniformly supplied chemical media induced spatially patterned fates in cell colony in a disc geometry. They provided significant evidence that inter-cellular mechanical interactions, as well as mechanical interactions between cells and the substrate, play an important role in this in vitro differentiation process. In this subsequent publication, we propose a mathematical model for this fate patterning process and explore how the fate pattern depends on substrate stiffness. One ingredient of this mathematical model is that the cells at the very edge of the colony (lacking adherens junctions on one side) are geometrically different than the rest (by occupying a larger area on the micropattern). These images of DAPI (staining nuclei) and ECad (at adherens junctions) for colonies during early cell differentiation demonstrate this difference. Corresponding code for analysis is included.
- Keyword:
- Biomechanics, Cell mechanics, and Developmental pattern formation
- Citation to related publication:
- Nunley H, Xue X, Fu, J, Lubensky, DK. Generation of fate patterns via intercellular forces. BioRxiv 442205 [Preprint]. April 30, 2021 [cited 2025 Feb 20]. Available from: doi: https://doi.org/10.1101/2021.04.30.442205 and Xue X, Sun Y, Resto-Irizarry A.M. et al. Mechanics-guided embryonic patterning of neuroectoderm tissue from human pluripotent stem cells. Nature Mater 17, 633–641 (2018). https://doi.org/10.1038/s41563-018-0082-9
- Discipline:
- Engineering and Science
-
- Creator:
- Nunley, Hayden, Xue, Xufeng, Sun, Yubing, Resto-Irizarry, Agnes M, Yuan, Ye, Yong, Koh Meng Aw, Zheng, Yi, Weng, Shinuo, Shao, Yue, Studer, Lorenz, Fu, Jianping, and Lubensky, David K
- Description:
- In an earlier study (Xue et al. Nature Materials 2018), stem cells differentiated into one of two cell types, neural plate border (NPB) or neural plate (NP), in vitro with the NP forming a central circular domain. This previous study demonstrated that this differentiation is likely mechanics-guided. Part of this demonstration was measurements of the displacement of microposts under the cell layer as the cells differentiate. These measurements suggested that the NPB cells are more contractile than NP cells (see Dataset of cell layers on micro-patterned substrates compost of posts). The authors of the 2018 study and of a follow-up study further explored how the size of the NPB domain depends on experimental conditions (see Dataset of stem cell colonies differentiating in neural induction medium and code for analysis of resulting fate pattern). To further understand what factors could be driving NPB formation, we estimated cell area at the colony edge (see Dataset on cell areas and nuclear densities in differentiating stem cell colonies). This analysis inspired a mathematical model of mechanical patterning: fate affects cell contractility, and pressure in the cell layer biases fate. Cells at the colony edge, more contractile than cells at the center, seed a pattern that propagates via force transmission. We simulated the model in various cell geometries and for different substrates (see Code for simulating NP/NPB fate patterning in stem cell colonies). Strikingly, our model implies that the width of the outer fate domain varies non-monotonically with substrate stiffness, a prediction that we confirm experimentally. Our findings thus support the idea that mechanical stress can mediate patterning in the complete absence of chemical morphogens, even in non-motile cell layers, thus expanding the repertoire of possible roles for mechanical signals in development and morphogenesis.
- Keyword:
- Biomechanics, Cell communication, Cell mechanics, Developmental pattern formation, Force Sensing, and Vertebrate development
- Discipline:
- Science
4Works -
- Creator:
- Howard, Cecilia M., Sheldon, Nathan D., Loveall, Zachary, Keating, Katarina A., Hong, Jungpyo, Smith, Selena Y., and Passey, Benjamin H.
- Description:
- This study uses an array of stratigraphic, morphological, and geochemical tools to investigate lateral and temporal variability in environmental records preserved by microbialites during a global hothouse environment. It also inverts tools for reconstructing environmental conditions to elucidate ancient microbial processes. Key Points: - The Green River Basin, WY, USA preserves lacustrine microbialites deposited during the Early Eocene Climatic Optimum, a period of high CO2 and temperatures - Morphological and geochemical analyses of these microbialites preserve variable local, regional, and global environmental conditions - Measurements of environmental conditions can be inverted to understand ancient microbial processes, which could be used to inform modeling of microbial influences on carbon cycling and Abstract: The Green River Basin, WY, USA, contains extensive lacustrine microbialite beds that formed during the hothouse Early Eocene Climatic Optimum (53–49 Ma). The records of biological, chemical, and physical processes preserved in these microbialites can inform our understanding of terrestrial conditions in this warm climate, but separating the competing signals of local, regional and global changes is difficult. Studies focusing on individual localities may miss spatial drivers of differences in microbialites. In this study, we used stratigraphic, morphological, and geochemical techniques to study microbialites deposited in the Green River Basin across three million years spanning the peak of the EECO, including samples from two beds covering 13–25 km of lateral extent. These samples cover a broad set of lake conditions as well as local differences such as spring deposits. We found that these microbialites preserved a mixture of conditions such as global hothouse temperatures, regional shifts in lake level, and local variability from sediment and water sources. Morphological and elemental variability were driven primarily by local and regional conditions such as stream, spring, and clastic inputs and water depth. Isotopic data preserved these local and regional changes as well as evidence of global hothouse conditions. Comparison of past [CO2] estimates to reconstructions using organic and inorganic carbon isotopes with clumped isotope-derived temperatures provides evidence for low to moderate microbial growth rates in these microbialite building communities, demonstrating that environmental tools can be inverted to better understand ancient microbial processes. A diverse toolkit was necessary to isolate the individual controls on microbialite records, and comparing across both space and time enabled us to identify local drivers that lead to significant differences from the expected regional signal.
- Keyword:
- Geosciences, Paleoclimate, Microbialite, Stromatolite, Eocene, Paleolake, and Green River Basin
- Citation to related publication:
- Howard, C.M. (2025). Unraveling Records of Time and Environment in Microbial Ecosystems from the Archean to Today (Ph.D. Dissertation). University of Michigan. and Howard, C.M., et al. (in prep). Disentangling Morphological and Chemical Records of Climate, Hydrology, and Diagenesis in Microbialites from the Eocene Green River Basin, WY, USA.
- Discipline:
- Science
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- Creator:
- Phillips, Chrystian D, DeFazio, R. Anthony, and Moenter, Suzanne M.
- Description:
- Supplemental tables containing the statistical analysis for the manuscript "Sex and time of day alter the interactions between hypothalamic glia and the neural circuits controlling reproduction"
- Discipline:
- Science
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- Creator:
- Raymond, Matt, Elvati, Paolo, Saldinger, Jacob C, Lin, Jonathan, Shi, Xuetao, and Violi, Angela
- Description:
- Nanoparticles (NPs) formed in nonthermal plasmas (NTPs) can have unique properties and applications. However, modeling their growth in these environments presents significant challenges due to the non-equilibrium nature of NTPs, making them computationally expensive to describe. In this work, we address the challenges associated with accelerating the estimation of parameters needed for these models. Specifically, we explore how different machine learning models can be tailored to improve prediction outcomes. We apply these methods to reactive classical molecular dynamics data, which capture the processes associated with colliding silane fragments in NTPs. These reactions exemplify processes where qualitative trends are clear, but their quantification is challenging, hard to generalize, and requires time-consuming simulations. Our results demonstrate that good prediction performance can be achieved when appropriate loss functions are implemented and correct invariances are imposed. While the diversity of molecules used in the training set is critical for accurate prediction, our findings indicate that only a fraction (15-25%) of the energy and temperature sampling is required to achieve high levels of accuracy. This suggests a substantial reduction in computational effort is possible for similar systems.
- Keyword:
- machine learning, molecular dynamics, nanoparticle, nonthermal plasma, silane, and sticking coefficient
- Citation to related publication:
- Raymond, M., Elvati, P., Saldinger, J. C., Lin, J., Shi, X., & Violi, A. (2025). Machine learning models for Si nanoparticle growth in nonthermal plasma. Plasma Sources Science and Technology. https://doi.org/10.1088/1361-6595/adbae1 and https://arxiv.org/abs/2501.00003
- Discipline:
- Science
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- Creator:
- Wang, Danhao and Mi, Zetian
- Description:
- Wurtzite ferroelectrics possess transformative potential for next-generation microelectronics. A comprehensive understanding of their ferroelectric properties and domain energetics is crucial for tailoring their ferroelectric characteristics and exploiting their functional properties in practical devices. Despite burgeoning interest, the exact configurations, and electronic structures of domain walls in wurtzite ferroelectrics remain elusive. In this work, we elucidate the atomic configurations and electronic properties of electric-field-induced domain walls in ferroelectric ScGaN. By combining transmission electron microscopy and theoretical calculations, a novel charged domain wall with a buckled two-dimensional hexagonal phase is revealed. Density functional theory calculations confirm that such domain wall structures further give rise to unprecedented mid-gap states within the forbidden band. Quantitative analysis unveils a universal charge-compensation mechanism stabilizing antipolar domain walls in ferroelectric materials, wherein the polarization discontinuity at the 180º domain wall is compensated by the unbonded valence electrons. Furthermore, the reconfigurable conductivity of these domain walls is experimentally demonstrated, showcasing their potential for ultra-scaled device applications. Our findings represent a pivotal advancement in understanding the structural and electronic properties of wurtzite ferroelectric domain walls and lay the groundwork for fundamental physics studies and device applications.
- Keyword:
- Charged domain walls, Scanning transmission electron microscopy, and Density functional theory calculations
- Discipline:
- Science