370 research outputs found
Cellâcell adhesion interface: orthogonal and parallel forces from contraction, protrusion, and retraction [version 1; referees: 2 approved]
The epithelial lateral membrane plays a central role in the integration of intercellular signals and, by doing so, is a principal determinant in the emerging properties of epithelial tissues. Mechanical force, when applied to the lateral cellâcell interface, can modulate the strength of adhesion and influence intercellular dynamics. Yet the relationship between mechanical force and epithelial cell behavior is complex and not completely understood. This commentary aims to provide an investigative look at the usage of cellular forces at the epithelial cellâcell adhesion interface
Searching for Intermediate Mass Black Holes in Globular Clusters Through Tidal Disruption Events
Intermediate mass black holes (IMBHs) may be the link between stellar mass
holes and the supermassive variety in the nuclei of galaxies, and globular
clusters (GCs) may be one of the most promising environments for their
formation. Here we carry out a pilot study of the observability of tidal
disruption events (TDEs) from 10^3 Msun < M_BH < 10^5 Msun IMBHs embedded in
stellar cusps at the center of GCs. We model the long super-Eddington accretion
phase and ensuing optical flare, and derive the disruption rate of
main-sequence stars as a function of black hole mass and GC properties with the
help of a 1D Fokker-Planck approach. The photospheric emission of the
adiabatically expanding outflow dominates the observable radiation and peaks in
the NUV/optical bands, outshining the brightness of the (old) stellar
population of GCs in Virgo for a period of months to years. A search for TDE
events in a sample of nearly 4,000 GCs observed at multiple epochs by the Next
Generation Virgo Cluster Survey (NGVS) yields null results. Given our model
predictions, this sample is too small to set stringent constraints on the
present-day occupation fraction of GCs hosting IMBHs. Naturally, better
simulations of the properties of the cluster central stellar distribution, TDE
light curves and rates, together with larger surveys of GCs are all needed to
gain deeper insights into the presence of IMBHs in GCs.Comment: 12 pages, 9 figures, submitted for publication in The Astrophysical
Journa
Applying Machine Learning to Crowd-sourced Data from Earthquake Detective
We present the Earthquake Detective dataset - A crowdsourced set of labels on
potentially triggered (PT) earthquakes and tremors. These events are those
which may have been triggered by large magnitude and often distant earthquakes.
We apply Machine Learning to classify these PT seismic events and explore the
challenges faced in segregating such low amplitude signals. The data set and
code are available online.Comment: Published in AI for Earth Sciences Workshop, NeurIPS 202
Advanced progress in recycling municipal and construction solid wastes for manufacturing sustainable construction materials
The sharply increasing solid waste generation has raised the environmental concerns worldwide which currently have been escalated to a worrying level. Intending to eliminate the negative environmental impacts of solid waste and meanwhile promote sustainability on the energy- and resource-intensive construction and building sector, considerable efforts have been devoted to recycling solid waste for the possible use in sustainable construction material products. This paper reviews the existing studies on recycling municipal and construction solid waste for the manufacture of geopolymer composites. Special attention is paid to the predominate performance of these geopolymer composite products. The principal findings of this work reveal that municipal and construction solid waste could be successfully incorporated into geopolymer composites in the forms of precursor, aggregate, additive, reinforcement fiber, or filling material. Additionally, the results indicate that although the inclusion of such waste might depress some of the attributes of geopolymer composites, proper proportion design and suitable treatment technique could alleviate these detrimental effects and further smooth the recycling progress. Finally, a brief discussion is provided to identify the important needs in the future research and development for promoting the utilization of solid waste materials in the forthcoming sustainable geopolymer industry. In summary, this work offers guidance for the better ecological choice to municipal and construction solid waste through developing waste materials into highly environmental-friendly construction materials
Synergistic effects of polypropylene and glass fiber on mechanical properties and durability of recycled aggregate concrete
To better understand the synergistic effects of combined fibers on mechanical properties and durability of recycled aggregate concrete (RAC), different types of fibers with various lengths and mass ratios were adopted in this study. Experimental investigations were conducted to study the 28-day compressive strength and strength loss after exposed to salt-solution freezeâthaw cycles and the coupled action of mechanical loading and salt-solution freezeâthaw cycles. The microstructure was also characterized to evaluate the mechanism of this synergistic effect. To determine the effectiveness of the combined fibers on improving the mechanical properties and durability of RAC, the synergistic coefficient was proposed and applied for various combinations of fibers. The results indicate that the incorporation of fibers slightly decreased the 28-day compressive strength of RAC, but combining different sizes and types of fibers can mitigate this negative effect. Moreover, the incorporation of fibers greatly improves the freezeâthaw resistance of RAC. The combining different fibers exhibited a synergistic effect on the enhancement in properties of RAC, which could not be predicted with only one simplistic rule of fibre mixtures. In addition, microstructural characterization shows that the bonding strength of the interfacial transition zone (ITZ) between the fiber and cement matrix is mainly determined by the chemical bonding force which is due to the hydration reaction between fiber surface and cement matrix
Myogenin regulates denervationâdependent muscle atrophy in mouse soleus muscle
Muscle inactivity due to injury or disease results in muscle atrophy. The molecular mechanisms contributing to muscle atrophy are poorly understood. However, it is clear that expression of atrophyârelated genes, like Atroginâ1 and MuRFâ1, are intimately tied to loss of muscle mass. When these atrophyârelated genes are knocked out, inactive muscles retain mass. Muscle denervation stimulates muscle atrophy and Myogenin (Myog) is a muscleâspecific transcription factor that is highly induced following muscle denervation. To investigate if Myog contributes to muscle atrophy, we have taken advantage of conditional Myog null mice. We show that in the denervated soleus muscle Myog expression contributes to reduced muscle force, mass, and crossâsectional area. We found that Myog mediates these effects, at least in part, by regulating expression of the Atroginâ1 and MuRFâ1 genes. Indeed Myog overâexpression in innervated muscle stimulates Atroginâ1 gene expression and Myog overâexpression stimulates Atroginâ1 promoter activity. Thus, Myog and the signaling cascades regulating its induction following muscle denervation may represent novel targets for therapies aimed at reducing denervationâinduced muscle atrophy. J. Cell. Biochem. 112: 2149â2159, 2011. © 2011 WileyâLiss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86926/1/23136_ftp.pd
House dust mites possess a polymorphic, single domain putative peptidoglycan d,l endopeptidase belonging to the NlpC/P60 Superfamily
AbstractA 14kDa protein homologous to the Îł-d-glutamyl-l-diamino acid endopeptidase members of the NlpC/P60 Superfamily has been described in Dermatophagoides pteronyssinus and Dermatophagoides farinae but it is not clear whether other species produce homologues. Bioinformatics revealed homologous genes in other Sarcopteformes mite species (Psoroptes ovis and Blomia tropicalis) but not in Tetranychus urticae and Metaseiulus occidentalis. The degrees of identity (similarity) between the D. pteronyssinus mature protein and those from D. farinae, P. ovis and B. tropicalis were 82% (96%), 77% (93%) and 61% (82%), respectively. Phylogenetic studies showed the mite proteins were monophyletic and shared a common ancestor with both actinomycetes and ascomycetes. The gene encoding the D. pteronyssinus protein was polymorphic and intronless in contrast to that reported for D. farinae. Homology studies suggest that the mite, ascomycete and actinomycete proteins are involved in the catalysis of stem peptide attached to peptidoglycan. The finding of a gene encoding a P60 family member in the D. pteronyssinus genome together with the presence of a bacterial promotor suggests an evolutionary link to one or more prokaryotic endosymbionts
- âŠ