A case was described with fast-slow form of atrioventricular nodal reentrant tachycardia as related with simultaneous fast and slow pathway conduction both antegrade and retrograde. Fast-slow form of tachycardia was induced by premature right atrial stimulation or incremental right ventricular pacing when the last paced beat conducted to the atria via both fast and slow pathways of the atrioventricular node causing double atrial response. Fast-slow form of tachycardia was spontaneously shifted to slow-fast form when the atrial echo, possibly through the retrograde intermediate pathway, was conducted antegradely over the fast and slow pathways simultaneously, producing double ventricular response.
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http://dx.doi.org/10.1111/j.1540-8159.1989.tb05052.x | DOI Listing |
Ann Bot
January 2025
Institute of Botany, Czech Academy of Sciences, Dukelská 135, 379 01 Třeboň, Czech Republic.
Background And Aims: Understanding interspecific differences in plant growth rates and their internal and external drivers is key to predicting species responses to ongoing environmental changes. Annual growth rates vary among plants based on their ecological preferences, growth forms, ecophysiological adaptations, and evolutionary history. However, the relative importance of these factors remains unclear, particularly in high-mountain ecosystems experiencing rapid changes.
View Article and Find Full Text PDFChaos
July 2024
School of Mathematics and Statistics, Yancheng Teachers University, Yancheng 224002, People's Republic of China.
In this study, considering a bi-stable plasma model with slow parametric excitation, the bifurcation of periodic and chaotic responses as well as the resulting fast-slow motions is discussed analytically and numerically. For a nonautonomous fast sub-system, the generalized harmonic balancing method is utilized to obtain an averaged system. Bifurcation analysis about the averaged system shows that the critical manifolds form a S-shape structure.
View Article and Find Full Text PDFJ Phys Chem A
July 2024
Department of Chemistry, University of California at Riverside, Riverside, California 92521, United States.
The ultraviolet (UV) photodissociation dynamics of the 1-methylallyl (1-MA) radical were studied using the high- Rydberg atom time-of-flight (HRTOF) technique in the wavelength region of 226-244 nm. The 1-MA radicals were produced by 193 nm photodissociation of the 3-chloro-1-butene and 1-chloro-2-butene precursor. The 1 + 1 REMPI spectrum of 1-MA agrees with the previous UV absorption spectrum in this wavelength region.
View Article and Find Full Text PDFCell Discov
June 2024
National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
Membrane budding, which underlies fundamental processes like endocytosis, intracellular trafficking, and viral infection, is thought to involve membrane coat-forming proteins, including the most observed clathrin, to form Ω-shape profiles and helix-forming proteins like dynamin to constrict Ω-profiles' pores and thus mediate fission. Challenging this fundamental concept, we report that polymerized clathrin is required for Ω-profiles' pore closure and that clathrin around Ω-profiles' base/pore region mediates pore constriction/closure in neuroendocrine chromaffin cells. Mathematical modeling suggests that clathrin polymerization at Ω-profiles' base/pore region generates forces from its intrinsically curved shape to constrict/close the pore.
View Article and Find Full Text PDFCogn Neurodyn
June 2024
School of Mathematics and Statistics, Henan University of Science and Technology, Luoyang, 471000 China.
A burst behavior observed in the lateral habenula (LHb) neuron related to major depressive disorder has attracted much attention. The burst is induced from silence by the excitatory -methyl-D-aspartate (NMDA) synapse or by the inhibitory stimulation, i.e.
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