We present an evolving network model in which the total numbers of nodes and edges are conserved, but in which edges are continuously rewired according to nonlinear preferential detachment and reattachment. Assuming power-law kernels with exponents alpha and beta , the stationary states which the degree distributions evolve toward exhibit a second-order phase transition-from relatively homogeneous to highly heterogeneous (with the emergence of starlike structures) at alpha=beta . Temporal evolution of the distribution in this critical regime is shown to follow a nonlinear diffusion equation, arriving at either pure or mixed power laws of exponents -alpha and 1-alpha .
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http://dx.doi.org/10.1103/PhysRevE.79.050104 | DOI Listing |
ACS Nano
January 2025
Conte Center for Polymer Research, Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States.
Bottlebrush block copolymers (BBCPs) are a unique class of materials that contain a backbone with densely grafted and chemically distinct polymeric side chains. The nonlinear architecture of BBCPs provides numerous degrees of freedom in their preparation, including control over key parameters such as grafting density, side chain length, block arrangement, and overall molecular weight. This uniquely branched structure provides BBCPs with several important distinctions from their linear counterparts, including sterically induced side chain and backbone conformations, rapid and large self-assembled nanostructures, and reduced or eliminated entanglement effects (assuming sufficient grafting density and that the molecular weight of the side chains is below their respective entanglement molecular weight).
View Article and Find Full Text PDFLangmuir
January 2025
Mechanical Engineering Department, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.
Electrorheological fluids are suspensions that are characterized by a strong functional dependence of their constitutive behavior on the local electric field. While such fluids are known to be promising in different applications of microfluidics including electrokinetic flows, their capabilities of controlling ion transport and preferential solute segregation in confined fluidic systems remain to be explored. In this work, we bring out the unique role of electrorheological fluids in orchestrating the selective enrichment and depletion of charged species in variable area microfluidic channels.
View Article and Find Full Text PDFAm J Psychiatry
January 2025
Department of Neuroscience, Medical University of South Carolina, Charleston (Kuhn, Crow, Walterhouse, Chalhoub, Dereschewitz, Roberts, Kalivas); School of Pharmacy, Center for Neuroscience, Pharmacology Unit, University of Camerino, Camerino, Italy (Cannella, Lunerti, Ciccocioppo); Interdisciplinary Ph.D. Program in Biostatistics (Gupta) and Department of Biomedical Informatics (Gupta, Allen, Chung), and Pelotonia Institute for Immuno-Oncology, James Comprehensive Cancer Center, Ohio State University, Columbus (Gupta, Allen, Chung); Department of Internal Medicine, Wake Forest University, Winston-Salem, NC (Cockerham, Beeson, Solberg Woods); Department of Psychology, Jacksonville State University, Jacksonville, AL (Nall); Institute for Genomic Medicine, University of California San Diego, La Jolla (Palmer); School of Biological Sciences, Queen's University Belfast, Belfast, Northern Ireland (Hardiman).
Objective: The behavioral and diagnostic heterogeneity within the opioid use disorder (OUD) diagnosis is not readily captured in current animal models, limiting the translational relevance of the mechanistic research that is conducted in experimental animals. The authors hypothesized that a nonlinear clustering of OUD-like behavioral traits would capture population heterogeneity and yield subpopulations of OUD vulnerable rats with distinct behavioral and neurocircuit profiles.
Methods: Over 900 male and female heterogeneous stock rats, a line capturing genetic and behavioral heterogeneity present in humans, were assessed for several measures of heroin use and rewarded and non-rewarded seeking behaviors.
Proc Natl Acad Sci U S A
January 2025
Department of Chemistry, University of California, Berkeley, CA 94720.
Combining Deep-UV second harmonic generation spectroscopy with molecular simulations, we confirm and quantify the specific adsorption of guanidinium cations to the air-water interface. Using a Langmuir analysis of measurements at multiple concentrations, we extract the Gibbs free energy of adsorption, finding it larger than typical thermal energies. Molecular simulations clarify the role of polarizability in tuning the thermodynamics of adsorption, and establish the preferential parallel alignment of guanidinium at the air-water interface.
View Article and Find Full Text PDFbioRxiv
December 2024
Department of Biochemistry, Brandeis University, Waltham, MA 02453.
Transcription activators trigger transcript production by RNA Polymerase II (RNApII) via the Mediator coactivator complex. Here the dynamics of activator, Mediator, and RNApII binding at promoter DNA were analyzed using multi-wavelength single-molecule microscopy of fluorescently labeled proteins in budding yeast nuclear extract. Binding of Mediator and RNApII to the template required activator and an upstream activator sequence (UAS), but not a core promoter.
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