1,398 research outputs found
Changes in tension regulates proliferation and migration of fibroblasts by remodeling expression of ECM proteins
No full textWound healing is a complicated but highly organized process in which cell migration and proliferation are actively involved. However, the process by which mechanical stretch regulates the proliferation and migration of human skin fibroblasts (HFs) and keratinocytes is poorly understood. Using a house built mechanical stretch device, we examined the HFs extracellular matrix (ECM) components changes under non-stretch, static stretch or cyclic stretch conditions. We further investigated the changes in ECM component protein expression levels in keratinocytes and analyzed the effects of individual ECM component on keratinocyte proliferation and migration. Particularly, the roles of calcium/calmodulin-dependent serine protein kinase (CASK) in the HF proliferation under cyclic stretch were investigated. Cyclic stretch suppressed HF proliferation compared with HFs without stretch or with static stretch. Cyclic stretch also led to a significant reduction in the levels of collagen I and a marked increase of fibronectin in HFs ECM. By contrast, collagen I levels increased and fibronectin levels decreased in response to non-stretch and static stretch conditions. After cyclic stretch, the proliferation of keratinocytes was inhibited by the cyclic stretch-induced ECM in HFs. The inoculation of keratinocytes with single ECM component suggested that collagen I was more capable of inducing cell proliferation than fibronectin, while it had less impact on cell migration compared with fibronectin. Furthermore, cyclic stretch induced by proliferation inhibition was associated with altered integrin 1-CASK signal pathway. The present results demonstrated the existence of HF-ECM-keratinocyte cross-talk' in cutaneous tissues. Thus, the integrin 1-CASK signal pathway in HFs may be involved in the outside-in signal transduction of extracellular stretch and the altered ECM component expression
A Study on the Acceptance of ECM Systems
No full textThe present paper summarizes selected results of the first au-thor‟s Master‟s thesis for the student track at the 10th Interna-tional Conference on Wirtschaftsinformatik in Zurich, Switzer-land. The thesis was co-supervised by the second and the third author. Building upon the technology acceptance model (TAM), the assignment was to investigate factors impacting on end users‟ acceptance of enterprise content management (ECM) systems. The study suggests twenty-two factors at the enterprise, process, technology, and content level that can influence ECM success. The results are grounded in both a systematic review of the lite-rature on ECM, including related fields such as document man-agement and records management, and an analysis of qualitative data collected from five ECM-adopting organizations. It is hoped that the findings will inform future Information Systems (IS) research on ECM acceptance. Practitioners can use the results in the process of planning and conducting their own ECM projects
ECM formation and degradation during fibrosis, repair, and regeneration
No full text\ua9 The Author(s) 2025.Imperfect attempts at organ repair after repeated injury result in aberrant formation of extracellular matrix (ECM) and loss of tissue structure. This abnormal ECM goes from being a consequence of cellular dysregulation to become the backbone of a persistently fibrotic cell niche that compromises organic function and ultimately drives systemic disease. Here, we review our current understanding of the structure of the ECM, the mechanisms behind organ-specific fibrosis, resolution, healing and regeneration, as well as the development of anti-fibrotic strategies. We also discuss the design of biomarkers to investigate fibrosis pathophysiology, track fibrosis progression, systemic damage, and fibrosis resolution
Radar electronic countermeasures (ECM) and electronic counter- countermeasures (ECCM)
No full textThis report provides an introduction to the concept of Electronic Warfare (EW) with particular emphasis on ECM and ECCM. ECM techniques such as Jamming and Deception will be discussed as well as ECCM techniques to counter them. It should be noted here that, due to classified nature of some of this subject matter, certain programs and systems as well as their corresponding techniques and tactics will be omitted. The author feels that a working understanding of ECM and ECCM can still be obtained from this report even though some specifics and details cannot be revealed.California State University, Northridge. Department of Engineering.Includes bibliographical references (pages 54-55
Epithelial polarity – Generating and integrating signals from the ECM with integrins
No full textAbstractEpithelial cells are important building blocks of most tissues and the corner stone of tissue architectures that allow directional transport of nutrients, ions and waste products in and out of the body. In tissues composed of millions of cells every individual cell needs to make right decisions when to differentiate, migrate, divide or die. Tight control of such fundamental cell-level processes ensures proper tissue morphogenesis, homeostasis and function. Cellular decisions are guided by biochemical and mechanical cues from their immediate microenvironment that consists of the extracellular matrix (ECM), neighboring cells and soluble factors. Generation of two distinct surfaces one facing the outside world (the apical domain) and the other contacting the neighboring cells and basal ECM (basolateral domain) is the most fundamental property of epithelial cells. The cues from the ECM are of particular importance in this process and communication between the cells and the ECM is largely mediated by transmembrane ECM receptors. Integrins constitute the largest family of such receptors binding to the ECM. Integrins have been shown to be essential for the establishment of initial polarity cues that define the position of the basal domain and thereby govern the orientation of the forming apico-basal axis. In this review I will discuss the multifaceted roles of integrins in epithelial cells with a particular focus on recent developments unveiling the specific functions of the different integrin heterodimers in regulating epithelial cell polarization and morphogenesis
A Reliable Way to Improve Electrochemical Migration (ECM) Resistance of Nanosilver Paste as a Bonding Material
No full textElectrochemical migration (ECM) of sintered nano-Ag could be a serious reliability concern for power devices with high-density packaging. An anti-ECM nano-Ag-SiOx paste was proposed by doping 0.1wt% SiOx nanoparticles rather than previously used expensive noble metals, e.g., palladium. The ECM lifetime of the sintered nano-Ag-SiOx was 1.5 to 3 times longer than that of the sintered nano-Ag, due to the fact that the SiOx could protect the Ag from oxidation. The thermo-mechanical reliability of the sintered nano-Ag-SiOx was also improved by sintering under 5 MPa assisted pressure. The lesser porosity and smaller grain boundaries of the sintered nano-Ag-SiOx could also be beneficial to retard the silver ECM. In the end, a double-sided semiconductor device was demonstrated to validate the better resistance to the ECM using the sintered nano-Ag-SiOx
Which types of shopping malls affect housing prices? From the perspective of spatial accessibility
No full textAuthor name used in this publication: 张凌Author name used in this publication: 周剑涛202312 bcchAccepted ManuscriptOthersThe Zhejiang Provincial Natural Science Foundation of ChinaPublishedGreen (AAM
Brain organoid formation on decellularized porcine brain ECM hydrogels
No full textHuman brain tissue models such as cerebral organoids are essential tools for developmental and biomedical research. Current methods to generate cerebral organoids often utilize Matrigel as an external scaffold to provide structure and biologically relevant signals. Matrigel however is a nonspecific hydrogel of mouse tumor origin and does not represent the complexity of the brain protein environment. In this study, we investigated the application of a decellularized adult porcine brain extracellular matrix (B-ECM) which could be processed into a hydrogel (B-ECM hydrogel) to be used as a scaffold for human embryonic stem cell (hESC)-derived brain organoids. We decellularized pig brains with a novel detergent- and enzyme-based method and analyzed the biomaterial properties, including protein composition and content, DNA content, mechanical characteristics, surface structure, and antigen presence. Then, we compared the growth of human brain organoid models with the B-ECM hydrogel or Matrigel controls in vitro. We found that the native brain source material was successfully decellularized with little remaining DNA content, while Mass Spectrometry (MS) showed the loss of several brain-specific proteins, while mainly different collagen types remained in the B-ECM. Rheological results revealed stable hydrogel formation, starting from B-ECM hydrogel concentrations of 5 mg/mL. hESCs cultured in B-ECM hydrogels showed gene expression and differentiation outcomes similar to those grown in Matrigel. These results indicate that B-ECM hydrogels can be used as an alternative scaffold for human cerebral organoid formation, and may be further optimized for improved organoid growth by further improving protein retention other than collagen after decellularization.CC BY 4.0© 2021 Simsa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.European Union's Horizon 2020 Research and Innovation Program under the Marie SklodowskaCurie Gran
The Effect of VEGF-ECM Crosstalk on Neural Stem Cell Behavior
No full textabstract: The endogenous response of neural stem cell/progenitor (NPSC) recruitment to the brain injury environment following a traumatic brain injury (TBI) is currently under heavy investigation. Mechanisms controlling NPSC proliferation and migration to the brain injury environment remain unclear; however, it is thought that the vascular extracellular matrix proteins (e.g. laminin, fibronectin, and vitronectin) and vascular endothelial growth factor (VEGF) play a role in mediating NPSC behavior through vasophillic interactions. This project attempts to uncover potential VEGF-ECM crosstalk in mediating migration and proliferation. To investigate migration, neurospheres were seeded on ECM-coated wells supplemented with VEGF and without VEGF, and neural outgrowth was measured at days 0, 1, 3, and 8 using differential interference contrast microscopy. Furthermore, single-cell NPSCs were seeded on ECM-coated Transwell membranes with VEGF supplemented media on one side and without VEGF to look at chemotactic migration. Migrated NPSCs were visualized with DAPI nuclear stain and imaged with an inverted fluorescent microscope. To investigate NPSC proliferation, NPSCs were seeded on ECM coated plates as in the radial migration assay and visualized with EdU on day 8. Total proliferation was measured by seeding NPSCs on ECM coated 96-well plates and incubating them with MTT on days 3 and 6. Proliferation was measured using a spectrophotometer at 630nm and 570nm wavelengths. It was found that VEGF-laminin crosstalk synergistically increased radial migration, but may not play a role in chemotactic migration. Understanding the mechanisms behind VEGF-laminin crosstalk in NPSC proliferation and migration may provide crucial information for the design of stem cell transplantation therapies in the future
In vitro and in silico findings on cell-cell and cell-ECM interactions during cellular aggregation and rearrangement:
No full textIn this dissertation, we present in silico and in vitro work on the dynamics of cellular aggregation and rearrangement as cell-cell and cell-ECM interactions are systematically varied. Computationally, we explore the contributions of homotypic and heterotypic forces between cells and the ECM affect cellular self-assembly. We find that variation of homotypic and heterotypic forces generates both expected morphologies and previously unreported patterns. Among the newly discovered patterns are segmented states of alternating cell types, and an “onion” state, in which cells form multilayer-aggregates of two cell types. Experimentally we varied cell-ECM adhesive strength through selection of α5β1-integrin receptor expression in Chinese Hamster Ovary (CHO) Cells at two soluble fibronectin (sFn) concentrations. Second, to describe dual adhesive relations, we used a CHO cell line variants coexpressing integrin and N-cadherin surface receptors. We found previously unreported complex behaviors of aggregates in these experiments. For example, we found that at constant sFn concentration, aggregate cohesion grows linearly as α5β1 receptor density is increased from low to moderate levels. However, further increase in receptor expression causes an abrupt drop in tissue cohesion. We propose that the observed biphasic property of these aggregates may be due to depletion of sFn below a critical value in the aggregate microenvironment at high α5β1 expression level. We also found that a complicated interplay emerges when cell-ECM and cell-cell interactions mediate cellular aggregation and rearrangement. Thus, we describe two nodes of cellular interaction, cell-ECM and cell-cell/cell-ECM. For weak cell-ECM interactions, cells can still rearrange, and new cellular patterns (e.g. inverted structures) emerge. For high cell-ECM strengths, cells are bound to the matrix and cannot rearrange. For weak and high cell-ECM interactions, cell-cell governs final equilibrium configurations. We propose that these results have potential implications for embryonic development, for wound healing, and for cancer therapeutic applications.Ph.D.Includes bibliographical referencesby Carlos Eduardo Caicedo-Carvaja
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