We have analyzed the behavior of a randomly triangulated, self-avoiding surface model of a flexible, fluid membrane subject to a circular boundary by Wang-Landau Monte Carlo computer simulation techniques. The dependence of the canonical free energy and frame tension on the frame area is obtained for flexible membranes. It is shown that for low bending rigidities the framed membrane is only stable above a threshold tension, suggesting a discontinuous transition from the collapsed (branched polymer) state to a finite tension extended state. In a tension range above this threshold tension the membranes display power-law characteristics for the equation of state, while higher tension levels includes both an extended linear (elastic) as well as a highly non-linear stretching regime. For semi-flexible membranes a transition from extended to buckled conformations takes place at negative frame tensions. Our analysis indicates that at zero frame tension the crumpling transition of fluid membranes show characteristics of both critical behavior and a discontinuous transition at low bending rigidities.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1140/epje/i2018-11651-6 | DOI Listing |
Biophys J
January 2025
Department of Chemical Engineering, Columbia University, New York, NY 10027. Electronic address:
Membrane fusion is central to fundamental cellular processes such as exocytosis, when an intracellular machinery fuses membrane-enclosed vesicles to the plasma membrane for contents release. The core machinery components are the SNARE proteins. SNARE complexation pulls the membranes together, but the fusion mechanism remains unclear.
View Article and Find Full Text PDFBiophys J
January 2025
Department of Biology, New York University, New York, New York, 10003, USA. Electronic address:
The outer membrane is the defining structure of Gram-negative bacteria. We previously demonstrated that it is a major load-bearing component of the cell envelope and is therefore critical to the mechanical robustness of the bacterial cell. Here, to determine the key molecules and moieties within the outer membrane that underlie its contribution to cell envelope mechanics, we measured cell-envelope stiffness across several sets of mutants with altered outer-membrane sugar content, protein content, and electric charge.
View Article and Find Full Text PDFAnn Biomed Eng
January 2025
Department of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115, USA.
Purpose: To evaluate the population variation in head-to-helmet contact forces in helmet users.
Methods: Four different size Kevlar composite helmets were instrumented with contact pressure sensors and chinstrap tension meters. A total number of 89 volunteers (25 female and 64 male volunteers) participated in the study.
Sci Rep
January 2025
Center of Excellence in Molecular Genetics of Cancer and Human Diseases, Department of Anatomy, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Bangkok, Thailand.
An ideal chemotherapeutic agent damages DNA, specifically in cancer cells, without harming normal cells. Recently, we used Box A of HMGB1 plasmid as molecular scissors to produce DNA gaps in normal cells. The DNA gap relieves DNA tension and increases DNA strength, preventing DNA double-strand breaks (DSBs).
View Article and Find Full Text PDFNat Commun
January 2025
Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India.
Single-point mutations are pivotal in molecular zoology, shaping functions and influencing genetic diversity and evolution. Here we study three such genetic variants of a mechano-responsive protein, cadherin-23, that uphold the structural integrity of the protein, but showcase distinct genotypes and phenotypes. The variants exhibit subtle differences in transient intra-domain interactions, which in turn affect the anti-correlated motions among the constituent β-strands.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!