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- 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
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- 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:
- 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
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- Creator:
- Brinkmeier, Michelle L, Wang, Su Qing, Pittman, Hannah, Cheung, Leonard Y, and Prasov, Lev
- Description:
- MYRF is a gene that regulates the development and function of the retinal pigmented epithelium (RPE), which play an important role in maintaining photoreceptor structure and function. Mutations in patients have been implicated in eye size disorders, particularly causing a small, but structurally normal eye. We have utilized a molecular technique, single cell RNA sequencing, to investigate how loss of Myrf specifically in the RPE in a mouse model impacts downstream gene expression at three developmental timepoints and used this information to define the role of Myrf in development. Our work identified key cytoskeletal structural genes specific to the RPE, Ermn and Upk3b, and a gene important for the cell survival, Sox10, as critical targets of Myrf. In addition, we have identified and confirmed that the TGFbeta signaling pathway is dysregulated when Myrf is lost during development. This pathway is particularly relevant in RPE health and eye growth. Our electron microscopy and histologic analyses also confirm a defect in RPE structure and function. We place MYRF within a hierarchy of genes involved in RPE development and introduce novel candidate genes for further study as retinal degeneration and nanophthalmos candidate genes.
- Keyword:
- ERMN, MYRF, Hypopigmentation, TMEM98, SOX10, Retinal Pigment Epithelium (RPE), and Retinal degeneration
- Discipline:
- Science
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- Creator:
- Kersten, Roland D, Ousley, D, Wang, Xiaofeng, Chigumba, Desnor N, Davis, Dulciana, Shafiq, Khadija, McDonough, Kali, Mydy, Lisa M, and Sexton, Jonathan Z
- Description:
- Moroidins are plant ribosomally synthesized and posttranslationally modified peptides (RiPPs) called burpitides biosynthesized from copper-dependent peptide cyclases. The bicyclic structure of moroidins contains (1) a stephanotic acid scaffold with a Leu-Cꞵ-Trp-indole-C6-crosslink and (2) a C-terminal ring formed by a Trp-indole-C2-His-imidazole-N1-crosslink. Moroidin is cytotoxic to H1437 non-small cell lung adenocarcinoma cells in vitro, underscoring the potential of stephanotic acid-type burpitides as anticancer lead structures and the importance of exploring diversification strategies to discover analogs with enhanced bioactivity. We mined the transcriptome of 7579 plant species from 498 plant families to identify moroidin analogs with novel second-ring structures and the cyclases responsible for their biosynthesis. A search of >27000 candidate burpitide cyclases reveals two stephanotic acid-type burpitides in plants with new second-ring crosslinks derived from posttranslational modification: Glechomanin from ground ivy (Glechoma hederacea) with a C-C-crosslink between a C-terminal tryptophan-indole-C6 and the β-carbon of a valine, and Mercurialin from annual mercury (Mercurialis annua) featuring a C-O-crosslink between a C-terminal tyrosine-phenol hydroxy and the β-carbon of a phenylalanine, respectively. Furthermore, our transcriptomics-guided burpitide genotyping enabled isolation of a moroidin analog from water chickweed (Stellaria aquatica), which exhibits a ten-fold higher in vitro cytotoxicity than moroidin and selective toxicity against H1437 lung adenocarcinoma cells. We demonstrate that plant transcriptome mining can expand the medicinal chemistry toolbox for chemical and biological exploration of burpitide lead structures.
- Keyword:
- RNA-seq, de novo transcriptome assembly, plant peptides, natural products, and RiPP
- Citation to related publication:
- in preparation
- Discipline:
- Science
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- Creator:
- University of Michigan Museum of Zoology
- Description:
- Scan of specimen ummz:herps:238369 (NOTOTRITON PICADOI) - Limbs. Raw Dataset includes 1601 TIF images (each 461 x 741 x 1 voxel at 0.01300206 mm resolution, derived from 1601 scan projections), xtek and vgi files for volume reconstruction. and Scan of specimen ummz:herps:238369 (NOTOTRITON PICADOI) - Limbs. Reconstructed Dataset includes 0.013002 TIF images (each 461 x 741 x 1 voxel at 0.013002 mm resolution, derived from 1601 scan projections), xtek and vgi files for volume reconstruction.
- Keyword:
- Animalia, Chordata, Amphibia, CAUDATA, PLETHODONTIDAE, NOTOTRITON PICADOI, 1987030882, computed tomography, X-ray, and 3D
- Citation to related publication:
- For more information on the original UMMZ specimen, see: https://www.gbif.org/occurrence/1987030882
- Discipline:
- Science
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- Creator:
- University of Michigan Museum of Zoology
- Description:
- Scan of specimen ummz:herps:194448 (PSEUDOTRITON RUBER) - Limbs. Raw Dataset includes 1601 TIF images (each 372 x 652 x 1 voxel at 0.03100344 mm resolution, derived from 1601 scan projections), xtek and vgi files for volume reconstruction. and Scan of specimen ummz:herps:194448 (PSEUDOTRITON RUBER) - Limbs. Reconstructed Dataset includes 0.031003 TIF images (each 372 x 652 x 1 voxel at 0.031003 mm resolution, derived from 1601 scan projections), xtek and vgi files for volume reconstruction.
- Keyword:
- Animalia, Chordata, Amphibia, CAUDATA, PLETHODONTIDAE, PSEUDOTRITON RUBER, 1987126336, computed tomography, X-ray, and 3D
- Citation to related publication:
- For more information on the original UMMZ specimen, see: https://www.gbif.org/occurrence/1987126336
- Discipline:
- Science
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- Creator:
- University of Michigan Museum of Zoology
- Description:
- Scan of specimen ummz:herps:143736 (PSEUDOEURYCEA BELLII) - Limbs. Raw Dataset includes 1601 TIF images (each 642 x 2000 x 1 voxel at 0.02199678 mm resolution, derived from 1601 scan projections), xtek and vgi files for volume reconstruction., Scan of specimen ummz:herps:143736 (PSEUDOEURYCEA BELLII) - Limbs. Reconstructed Dataset includes 0.021997 TIF images (each 642 x 2000 x 1 voxel at 0.021997 mm resolution, derived from 1601 scan projections), xtek and vgi files for volume reconstruction., and Scan of specimen ummz:herps:143736 (PSEUDOEURYCEA BELLII) - Limbs. Reconstructed Dataset includes 0.021997 TIF images (each 642 x 2000 x 1 voxel at 0.021997 mm resolution, derived from 1601 scan projections), xtek and vgi files for volume reconstruction.
- Keyword:
- Animalia, Chordata, Amphibia, CAUDATA, PLETHODONTIDAE, PSEUDOEURYCEA BELLII, 1987206748, computed tomography, X-ray, and 3D
- Citation to related publication:
- For more information on the original UMMZ specimen, see: https://www.gbif.org/occurrence/1987206748
- Discipline:
- Science