Using a judicious spatial shape of input current pulses (and electrodes), responses of an excitable system (FitzHugh-Nagumo) appear as unidirectional pulses (UDP's) instead of bidirectional ones (in one dimension) or circular ones (in two dimensions). The importance of the UDP's for a possible mechanism for pinpointing the reentry cycle position and for a possible use in tachycardia suppression is discussed.
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http://dx.doi.org/10.1103/PhysRevE.70.041903 | DOI Listing |
Chaos
January 2025
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, USA.
Traveling waves of excitation arise from the spatial coupling of local nonlinear events by transport processes. In corrosion systems, these electro-dissolution waves relay local perturbations across large portions of the metal surface, significantly amplifying overall damage. For the example of the magnesium alloy AZ31B exposed to sodium chloride solution, we report experimental results suggesting the existence of a vulnerable zone in the wake of corrosion waves where local perturbations can induce a unidirectional wave pulse or segment.
View Article and Find Full Text PDFTheranostics
January 2025
College of Pharmacy, Seoul National University, Seoul 08826, South Korea.
Hypoxia is a major obstacle in the treatment of solid tumors because it causes immune escape and therapeutic resistance. Drug penetration into the hypoxic regions of tumor microenvironment (TME) is extremely limited. This study proposes using the unidirectional fluid flow property of low-intensity pulsed ultrasound (LIPUS) to overcome drug penetration limitations in the TME.
View Article and Find Full Text PDFACS Appl Bio Mater
December 2024
Materials Department, University of California, Santa Barbara, California 93106, United States.
Pancreatic ductal adenocarcinoma (PDAC) is a cancer of the epithelia comprising the ductal network of the pancreas. During disease progression, PDAC tumors recruit fibroblasts that promote fibrosis, increasing local tissue stiffness and subjecting epithelial cells to increased compressive forces. Previous in vitro studies have documented cytoskeletal and nuclear adaptation following compressive stresses in two-dimensional (2D) and three-dimensional (3D) environments.
View Article and Find Full Text PDFJ Virol
December 2024
Transplantation & Clinical Virology, Department of Biomedicine, University of Basel, Basel, Switzerland.
BK polyomavirus (BKPyV) contributes to premature renal failure in 10%-20% of kidney transplant recipients. Current treatment relies on reducing immunosuppression to regain BKPyV-specific immune control. Subsequently, declining allograft function may result from persisting viral cytopathology, BKPyV-specific immune reconstitution, or alloimmunity/rejection, all being poorly distinguishable by current histological or molecular approaches.
View Article and Find Full Text PDFElife
October 2024
Department of Physics, Freie Universität Berlin, Berlin, Germany.
Lipopolysaccharides (LPS) confer resistance against harsh conditions, including antibiotics, in Gram-negative bacteria. The lipopolysaccharide transport (Lpt) complex, consisting of seven proteins (A-G), exports LPS across the cellular envelope. LptBFG forms an ATP-binding cassette transporter that transfers LPS to LptC.
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