There has been considerable interest in characterizing the polymer layer that is effectively irreversibly bound to nanoparticles (NPs) because it is thought to underpin the unusual thermomechanical properties of polymer nanocomposites (PNC). We study PNCs formed by mixing silica nanoparticles (NPs) with poly-2-vinylpyridine (P2VP) and compare the bound layer thickness δ determined by three different methods. We show that the thickness obtained by thermogravimetric analysis (TGA) and assuming that the bound layer has a density corresponding to a dense melt clearly underestimates the real bound layer thickness. A more realistic extent of the bound layer is obtained by in situ measurements of the interaction pair potential between NPs in PNCs via analysis of TEM micrographs; we verify these estimates using Dynamic Light Scattering (DLS) in θ solvent. Our results confirm the existence of long-ranged interactions between NPs corresponding roughly in size to the radius of gyration of the bound chains.
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Microbes of nearly every species can form biofilms, communities of cells bound together by a self-produced matrix. It is not understood how variation at the cellular level impacts putatively beneficial, colony-level behaviors, such as cell-to-cell signaling. Here we investigate this problem with an agent-based computational model of metabolically driven electrochemical signaling in Bacillus subtilis biofilms.
View Article and Find Full Text PDFEnviron Res
January 2025
State Key Laboratory of Soil & Sustainable Agriculture, Institute of soil science, Chinese academy of sciences, Nanjing 211135, China. Electronic address:
Layered double hydroxide intercalated with mercaptosuccinic acid (MSA-CFA) holds considerable promise for remediating cadmium (Cd)-contaminated soils through selective immobilization; however, its stability under acidic conditions has yet to be investigated. The acidic stability of MSA-CFA was investigated by acid stability investigation and simulated soil acidification. In the immersion test, the cadmium dissolution rate (DR) for the Cd immobilized products of MSA-CFA (MSA-CFA-Cd) was significantly lower (2.
View Article and Find Full Text PDFWater Res
December 2024
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, PR China.
Membrane separation technology has emerged as a highly energy-efficient method for microalgae enrichment and harvesting in wastewater treatment. However, membrane fouling caused by algal cells and stratified extracellular polymeric substances (EPS) remains a critical barrier to its industrial-scale application. This study meticulously investigates the micro process of algae-derived pollutants stacking to the membrane surface affected by stratified EPS.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
Centre for Nanobiotechnology, Vellore Institute of Technology, Vellore, Tamil Nadu, India. Electronic address:
The current work seeks to understand how the interactions between ZnO QDs and extracellular polymeric substances (EPS) may vary based on the types of EPS (loosely and tightly bound) and modes of eco-corona formation (In-situ or ex-situ). In-situ eco-corona refers to formation of an EPS layer on the QDs during the interactions with the algae whereas the ex-situ condition refers to forming the layer before the interactions. ZnO QDs were added at 0.
View Article and Find Full Text PDFNat Commun
January 2025
Goethe University Frankfurt, Institute for Cardiovascular Physiology, Frankfurt, Germany.
The coordination of chromatin remodeling is essential for DNA accessibility and gene expression control. The highly conserved and ubiquitously expressed SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex plays a central role in cell type- and context-dependent gene expression. Despite the absence of a defined DNA recognition motif, SWI/SNF binds lineage specific enhancers genome-wide where it actively maintains open chromatin state.
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