We give an overview of mathematical models of renal physiology and anatomy with the clinician in mind. Beyond the past focus on issues of local transport mechanisms along the nephron and the urine concentrating mechanism, recent models have brought insight into difficult problems such as renal ischemia (oxygen and CO diffusion in the medulla) or calcium and potassium homeostasis. They have also provided revealing 3D reconstructions of the full trajectories of families of nephrons and collecting ducts through cortex and medulla. The recent appearance of sophisticated whole-kidney models representing nephrons and their associated renal vasculature promises more realistic simulation of renal pathologies and pharmacological treatments in the foreseeable future.
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http://dx.doi.org/10.1016/j.morpho.2019.10.043 | DOI Listing |
Chaos
January 2025
Physics Institute, University of São Paulo, 05508-090 São Paulo, SP, Brazil.
In this work, we investigate the dynamics of a discrete-time prey-predator model considering a prey reproductive response as a function of the predation risk, with the prey population growth factor governed by two parameters. The system can evolve toward scenarios of mutual or only of predators extinction, or species coexistence. We analytically show all different types of equilibrium points depending on the ranges of growth parameters.
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January 2025
Agricultural and Ecological Research Unit, Indian Statistical Institute, 203 B. T. Road, Kolkata 700108, India.
Experimental observations and field data demonstrated that predators adapt their hunting strategies in response to prey abundance. While previous studies explored the impact of predation risk on predator-prey interactions, the impact of symbiotic relationships between fear-affected prey and non-prey species on system dynamics remains unexplored. This study uses a mathematical approach to investigate how different symbiotic relationships govern system dynamics when predators adapt to prey availability.
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January 2025
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
Spirals are a special class of excitable waves that have its significance in the understanding of cardiac arrests and neuronal transduction. In a theoretical model of the chemical Belousov-Zhabotinsky reaction system, we explore the dynamics of the spatiotemporal patterns that emerge out of competing reaction and diffusion phenomena. By modifying the existing mathematical models of the reaction kinetics, we have been able to explore the explicit effect of hydrogen ion concentration in the system, so as to achieve various regimes of wave activity, from stable spirals to oscillation death.
View Article and Find Full Text PDFJMIR Form Res
January 2025
Vaccine Study Center, Northern California Division of Research, Kaiser Permanente, Oakland, CA, United States.
Background: Real-world COVID-19 vaccine effectiveness (VE) studies are investigating exposures of increasing complexity accounting for time since vaccination. These studies require methods that adjust for the confounding that arises when morbidities and demographics are associated with vaccination and the risk of outcome events. Methods based on propensity scores (PS) are well-suited to this when the exposure is dichotomous, but present challenges when the exposure is multinomial.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of Regensburg, Faculty of Chemistry and Pharmacy, Institute of Inorganic Chemistry, Universitätsstraße 31, D-93053, Regensburg, GERMANY.
Aminophosphates are the focus of research on prebiotic phosphorylation chemistry. Their bifunctional nature also makes them a powerful class of organocatalysts. However, the structural chemistry and dynamics of proton-binding in phosphorylation and organocatalytic mechanisms are still not fully understood.
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