2,998 results match your criteria Bulletin Of Mathematical Biology[Journal]


A Mathematical Model for Inheritance of DNA Methylation Patterns in Somatic Cells.

Bull Math Biol 2020 Jul 1;82(7):84. Epub 2020 Jul 1.

Department of Mathematics, University of Utah, Salt Lake City, UT, 84112, USA.

DNA methylation is an essential epigenetic mechanism used by cells to regulate gene expression. Interestingly, DNA replication, a function necessary for cell division, disrupts the methylation pattern. Since perturbed methylation patterns are associated with aberrant gene expression and many diseases, including cancer, restoration of the correct pattern following DNA replication is crucial. Read More

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http://dx.doi.org/10.1007/s11538-020-00765-4DOI Listing

The Impact of Pre-exposure Prophylaxis for Human Immunodeficiency Virus on Gonorrhea Prevalence.

Bull Math Biol 2020 Jul 1;82(7):85. Epub 2020 Jul 1.

Department of Applied Mathematics, University of Waterloo, 200 University Ave West, Waterloo, ON, N2L 3G1, Canada.

Pre-exposure prophylaxis (PrEP) has been shown to be highly effective in reducing the risk of HIV infection in gay and bisexual men who have sex with men (GbMSM). However, PrEP does not protect against other sexually transmitted infections (STIs). In some populations, PrEP has also led to riskier behavior such as reduced condom usage, with the result that the prevalence of bacterial STIs like gonorrhea has increased. Read More

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http://dx.doi.org/10.1007/s11538-020-00762-7DOI Listing

Modeling Clot Formation of Shear-Injured Platelets in Flow by a Dissipative Particle Dynamics Method.

Bull Math Biol 2020 Jun 22;82(7):83. Epub 2020 Jun 22.

Department of Surgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF 436, Baltimore, MD, 21201, USA.

The regions with high non-physiological shear stresses (NPSS) are inevitable in blood-contacting medical devices (BCMDs) used for mechanically assisted circulatory support. NPSS can cause platelet activation and receptor shedding potentially resulting in the alteration of hemostatic function. In this study, we developed a dissipative particle dynamics model to characterize clot formation (platelet-collagen and inter-platelet adhesion) of NPSS-traumatized blood at a vascular injury site. Read More

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http://dx.doi.org/10.1007/s11538-020-00760-9DOI Listing

A Mathematical Dissection of the Adaptation of Cell Populations to Fluctuating Oxygen Levels.

Bull Math Biol 2020 Jun 16;82(6):81. Epub 2020 Jun 16.

School of Mathematics and Statistics, University of St Andrews, St Andrews, KY16 9SS, UK.

The disordered network of blood vessels that arises from tumour angiogenesis results in variations in the delivery of oxygen into the tumour tissue. This brings about regions of chronic hypoxia (i.e. Read More

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http://dx.doi.org/10.1007/s11538-020-00754-7DOI Listing

Game-Theoretical Model of Retroactive Hepatitis B Vaccination in China.

Bull Math Biol 2020 Jun 15;82(6):80. Epub 2020 Jun 15.

Department of Mathematics and Applied Mathematics, Virginia Commonwealth University, Richmond, VA, 23284-2014, USA.

Hepatitis B (HepB) is one of the most common infectious diseases affecting over two billion people worldwide. About one third of all HepB cases are in China. In recent years, China made significant efforts to implement a nationwide HepB vaccination program and reduced the number of unvaccinated infants from 30 to 10%. Read More

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http://dx.doi.org/10.1007/s11538-020-00748-5DOI Listing

Multiple Attractors and Long Transients in Spatially Structured Populations with an Allee Effect.

Bull Math Biol 2020 Jun 16;82(6):82. Epub 2020 Jun 16.

Institute of Mathematics and Institute of Environmental Systems Research, Osnabrück University, 49076, Osnabrück, Germany.

We present a discrete-time model of a spatially structured population and explore the effects of coupling when the local dynamics contain a strong Allee effect and overcompensation. While an isolated population can exhibit only bistability and essential extinction, a spatially structured population can exhibit numerous coexisting attractors. We identify mechanisms and parameter ranges that can protect the spatially structured population from essential extinction, whereas it is inevitable in the local system. Read More

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http://dx.doi.org/10.1007/s11538-020-00750-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7295732PMC

Nonreflecting Boundary Conditions for a CSF Model of Fourth Ventricle: Spinal SAS Dynamics.

Bull Math Biol 2020 Jun 13;82(6):77. Epub 2020 Jun 13.

Department of Information Engineering, Computer Science and Mathematics, University of L'Aquila, 67100, L'Aquila, Italy.

In this paper, we introduce a one-dimensional model for analyzing the cerebrospinal fluid dynamics within the fourth ventricle and the spinal subarachnoid space (SSAS). The model has been derived starting from an original model of Linninger et al. and from the detailed mathematical analysis of two different reformulations. Read More

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http://dx.doi.org/10.1007/s11538-020-00749-4DOI Listing

Correction to: Modulation of the cAMP Response by G[Formula: see text] and G[Formula: see text]: A Computational Study of G Protein Signaling in Immune Cells.

Bull Math Biol 2020 Jun 13;82(6):79. Epub 2020 Jun 13.

Department of Mathematics, The Ohio State University, Columbus, OH, 43210, USA.

The original version of this article unfortunately contained mistakes. Read More

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http://dx.doi.org/10.1007/s11538-020-00753-8DOI Listing

A Framework for Network-Based Epidemiological Modeling of Tuberculosis Dynamics Using Synthetic Datasets.

Bull Math Biol 2020 Jun 13;82(6):78. Epub 2020 Jun 13.

Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA.

We present a framework for discrete network-based modeling of TB epidemiology in US counties using publicly available synthetic datasets. We explore the dynamics of this modeling framework by simulating the hypothetical spread of disease over 2 years resulting from a single active infection in Washtenaw County, MI. We find that for sufficiently large transmission rates that active transmission outweighs reactivation, disease prevalence is sensitive to the contact weight assigned to transmissions between casual contacts (that is, contacts that do not share a household, workplace, school, or group quarter). Read More

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http://dx.doi.org/10.1007/s11538-020-00752-9DOI Listing

Thermodynamic Inhibition in Chemostat Models : With an Application to Bioreduction of Uranium.

Bull Math Biol 2020 Jun 13;82(6):76. Epub 2020 Jun 13.

, 50 Stone Rd. E., Guelph, ON, N1G 2W1, Canada.

We formulate a mathematical model of bacterial populations in a chemostat setting that also accounts for thermodynamic growth inhibition as a consequence of chemical reactions. Using only elementary mathematical and chemical arguments, we carry this out for two systems: a simple toy model with a single species, a single substrate, and a single reaction product, and a more involved model that describes bioreduction of uranium[VI] into uranium[IV]. We find that in contrast to most traditional chemostat models, as a consequence of thermodynamic inhibition the equilibria concentrations of nutrient substrates might depend on their inflow concentration and not only on reaction parameters and the reactor's dilution rate. Read More

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http://dx.doi.org/10.1007/s11538-020-00758-3DOI Listing

Modeling the Effects of Meteorological Factors and Unreported Cases on Seasonal Influenza Outbreaks in Gansu Province, China.

Bull Math Biol 2020 Jun 12;82(6):73. Epub 2020 Jun 12.

Department of Applied Mathematics, Lanzhou University of Technology, Lanzhou, 730050, Gansu, People's Republic of China.

Influenza usually breaks out seasonally in temperate regions, especially in winter, infection rates and mortality rates of influenza increase significantly, which means that dry air and cold temperatures accelerate the spread of influenza viruses. However, the meteorological factors that lead to seasonal influenza outbreaks and how these meteorological factors play a decisive role in influenza transmission remain unclear. During the epidemic of infectious diseases, the neglect of unreported cases leads to an underestimation of infection rates and basic reproduction number. Read More

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http://dx.doi.org/10.1007/s11538-020-00747-6DOI Listing

Population Dynamics with Threshold Effects Give Rise to a Diverse Family of Allee Effects.

Bull Math Biol 2020 Jun 12;82(6):74. Epub 2020 Jun 12.

School of Mathematical Sciences, Queensland University of Technology, Brisbane, QLD, 4001, Australia.

The Allee effect describes populations that deviate from logistic growth models and arises in applications including ecology and cell biology. A common justification for incorporating Allee effects into population models is that the population in question has altered growth mechanisms at some critical density, often referred to as a threshold effect. Despite the ubiquitous nature of threshold effects arising in various biological applications, the explicit link between local threshold effects and global Allee effects has not been considered. Read More

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http://dx.doi.org/10.1007/s11538-020-00756-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7292819PMC

Optimizing the Timing and Composition of Therapeutic Phage Cocktails: A Control-Theoretic Approach.

Bull Math Biol 2020 Jun 12;82(6):75. Epub 2020 Jun 12.

School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA.

Viruses that infect bacteria, i.e., bacteriophage or 'phage,' are increasingly considered as treatment options for the control and clearance of bacterial infections, particularly as compassionate use therapy for multi-drug-resistant infections. Read More

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http://dx.doi.org/10.1007/s11538-020-00751-wDOI Listing

Parameter and State Estimation in a Cholera Model with Threshold Immunology: A Case Study of Senegal.

Bull Math Biol 2020 Jun 11;82(6):72. Epub 2020 Jun 11.

Institute of Mathematical Sciences, Strathmore University, P.O. Box 59857-00200, Nairobi, Kenya.

It is often impossible to measure all states affecting spread of a disease. In cholera, asymptomatic and cholera pathogen densities are not practically measurable despite playing a big role in its transmission. They are referred to as inaccessible states of the model and can only be manipulated using the measurable states of the given model. Read More

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http://dx.doi.org/10.1007/s11538-020-00755-6DOI Listing

Parameter Estimation for Evaporation-Driven Tear Film Thinning.

Bull Math Biol 2020 Jun 6;82(6):71. Epub 2020 Jun 6.

School of Optometry, Indiana University, Bloomington, IN, 47405, USA.

Many parameters affect tear film thickness and fluorescent intensity distributions over time; exact values or ranges for some are not well known. We conduct parameter estimation by fitting to fluorescent intensity data recorded from normal subjects' tear films. The fitting is done with thin film fluid dynamics models that are nonlinear partial differential equation models for the thickness, osmolarity and fluorescein concentration of the tear film for circular (spot) or linear (streak) tear film breakup. Read More

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http://dx.doi.org/10.1007/s11538-020-00745-8DOI Listing

The Space of Tree-Based Phylogenetic Networks.

Bull Math Biol 2020 Jun 4;82(6):70. Epub 2020 Jun 4.

Centre for Research in Mathematics and Data Science, Western Sydney University, Sydney, Australia.

Phylogenetic networks are generalizations of phylogenetic trees that allow the representation of reticulation events such as horizontal gene transfer or hybridization, and can also represent uncertainty in inference. A subclass of these, tree-based phylogenetic networks, have been introduced to capture the extent to which reticulate evolution nevertheless broadly follows tree-like patterns. Several important operations that change a general phylogenetic network have been developed in recent years and are important for allowing algorithms to move around spaces of networks; a vital ingredient in finding an optimal network given some biological data. Read More

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http://dx.doi.org/10.1007/s11538-020-00744-9DOI Listing

Rescorla-Wagner Models with Sparse Dynamic Attention.

Bull Math Biol 2020 Jun 4;82(6):69. Epub 2020 Jun 4.

Department of Mathematics and Population Health Sciences, University of Wisconsin - Madison, Madison, WI, USA.

The Rescorla-Wagner (R-W) model describes human associative learning by proposing that an agent updates associations between stimuli, such as events in their environment or predictive cues, proportionally to a prediction error. While this model has proven informative in experiments, it has been posited that humans selectively attend to certain cues to overcome a problem with the R-W model scaling to large cue dimensions. We formally characterize this scaling problem and provide a solution that involves limiting attention in a R-W model to a sparse set of cues. Read More

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http://dx.doi.org/10.1007/s11538-020-00743-wDOI Listing

Comparison of Drug Inhibitory Effects ([Formula: see text]) in Monolayer and Spheroid Cultures.

Bull Math Biol 2020 Jun 3;82(6):68. Epub 2020 Jun 3.

Department of Mathematical Sciences, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, USA.

Traditionally, the monolayer (two-dimensional) cell cultures are used for initial evaluation of the effectiveness of anticancer drugs. In particular, these experiments provide the [Formula: see text] curves that determine drug concentration that can inhibit growth of a tumor colony by half when compared to the cells grown with no exposure to the drug. Low [Formula: see text] value means that the drug is effective at low concentrations, and thus will show lower systemic toxicity when administered to the patient. Read More

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http://dx.doi.org/10.1007/s11538-020-00746-7DOI Listing

Analysis of Multilevel Replicator Dynamics for General Two-Strategy Social Dilemma.

Authors:
Daniel B Cooney

Bull Math Biol 2020 May 30;82(6):66. Epub 2020 May 30.

Program in Applied and Computational Mathematics, Princeton University, Princeton, NJ, USA.

Here, we consider a game-theoretic model of multilevel selection in which individuals compete based on their payoff and groups also compete based on the average payoff of group members. Our focus is on multilevel social dilemmas: games in which individuals are best off cheating, while groups of individuals do best when composed of many cooperators. We analyze the dynamics of the two-level replicator dynamics, a nonlocal hyperbolic PDE describing deterministic birth-death dynamics for both individuals and groups. Read More

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http://dx.doi.org/10.1007/s11538-020-00742-xDOI Listing

Collective Pulsing in Xeniid Corals: Part II-Using Computational Fluid Dynamics to Determine if There are Benefits to Coordinated Pulsing.

Bull Math Biol 2020 May 30;82(6):67. Epub 2020 May 30.

Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.

Coordinated movements have been shown to enhance the speed or efficiency of swimming, flying, and pumping in many organisms. Coordinated pulsing has not been observed in many cnidarians (jellyfish, anemones, corals), as is the case for the xeniid corals considered in our corresponding paper. This observation opens the question as to whether xeniid corals, and cnidarians in general, do not coordinate their pulsing behavior for lack of a hydrodynamic advantage or for other reasons. Read More

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http://dx.doi.org/10.1007/s11538-020-00741-yDOI Listing

Cell-Scale Degradation of Peritumoural Extracellular Matrix Fibre Network and Its Role Within Tissue-Scale Cancer Invasion.

Bull Math Biol 2020 May 26;82(6):65. Epub 2020 May 26.

Division of Mathematics, University of Dundee, Dundee, DD1 4HN, Scotland, UK.

Local cancer invasion of tissue is a complex, multiscale process which plays an essential role in tumour progression. During the complex interaction between cancer cell population and the extracellular matrix (ECM), of key importance is the role played by both bulk two-scale dynamics of ECM fibres within collective movement of the tumour cells and the multiscale leading edge dynamics driven by proteolytic activity of the matrix-degrading enzymes (MDEs) that are secreted by the cancer cells. As these two multiscale subsystems share and contribute to the same tumour macro-dynamics, in this work we develop further the model introduced in Shuttleworth and Trucu (Bull Math Biol 81:2176-2219, 2019. Read More

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http://dx.doi.org/10.1007/s11538-020-00732-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7250813PMC

Stochastic Model of Bovine Babesiosis with Juvenile and Adult Cattle.

Bull Math Biol 2020 May 19;82(6):64. Epub 2020 May 19.

Department of Mathematics and Statistics, University of Victoria, Victoria, Canada.

A stochastic model for Bovine Babesiosis (BB) including ticks, and both juvenile and adult cattle is developed. This model is formulated by a system of continuous-time Markov chains (CTMCs) that is derived based on an extension of the deterministic ordinary differential equation model developed by Saad-Roy et al. (Bull Math Biol 77:514-547, 2015). Read More

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http://dx.doi.org/10.1007/s11538-020-00734-xDOI Listing

Undergraduate Quantitative Biology Impact on Biology Preservice Teachers.

Bull Math Biol 2020 May 19;82(6):63. Epub 2020 May 19.

University of Kansas, Lawrence, USA.

Quantitative biology is a rapidly advancing field in the biological sciences, particularly given the rise of large datasets and computer processing capabilities that have continually expanded over the past 50 years. Thus, the question arises, How should K-12 biology teachers incorporate quantitative biology skills into their biology curriculum? The teaching of quantitative biology has not been readily integrated into undergraduate biology curricula that impact preservice teachers. This has potential to cascade effects downward into the quality of learning about quantitative biology that can be expected in K-12 contexts. Read More

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http://dx.doi.org/10.1007/s11538-020-00740-zDOI Listing

A Mathematical Model for the Kinetics of the MalFGK[Formula: see text] Maltose Transporter.

Bull Math Biol 2020 May 15;82(5):62. Epub 2020 May 15.

Department of Mathematics, University of British Columbia, Vancouver, Canada.

The MalFGK[Formula: see text] transporter regulates the movement of maltose across the inner membrane of E. coli and serves as a model system for bacterial ATP binding cassette (ABC) importers. Despite the wealth of biochemical and structural data available, a general model describing the various translocation pathways is still lacking. Read More

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http://dx.doi.org/10.1007/s11538-020-00737-8DOI Listing

Opportunities for Change in the First Two Years of College Mathematics.

Authors:
David M Bressoud

Bull Math Biol 2020 May 14;82(5):61. Epub 2020 May 14.

Macalester College, Saint Paul, MN, USA.

This is a survey of the developments in the first two years of undergraduate mathematics, beginning in the early 1950s and continuing up to the present. It documents the repeated efforts at making this instruction relevant to the partner disciplines, especially Biology, and describes the challenges for the future. Read More

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http://dx.doi.org/10.1007/s11538-020-00738-7DOI Listing

Meeting the Needs of A Changing Landscape: Advances and Challenges in Undergraduate Biology Education.

Authors:
Melissa L Aikens

Bull Math Biol 2020 May 13;82(5):60. Epub 2020 May 13.

Department of Biological Sciences, University of New Hampshire, Durham, NH, USA.

Over the last 25 years, reforms in undergraduate biology education have transformed the way biology is taught at many institutions of higher education. This has been fueled in part by a burgeoning discipline-based education research community, which has advocated for evidence-based instructional practices based on findings from research. This perspective will review some of the changes to undergraduate biology education that have gained or are currently gaining momentum, becoming increasingly common in undergraduate biology classrooms. Read More

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http://dx.doi.org/10.1007/s11538-020-00739-6DOI Listing

Paying Our Dues: The Role of Professional Societies in the Evolution of Mathematical Biology Education.

Bull Math Biol 2020 May 12;82(5):59. Epub 2020 May 12.

Department of Mathematics, University of Pittsburgh, Pittsburgh, PA, USA.

Mathematical biology education provides key foundational underpinnings for the scholarly work of mathematical biology. Professional societies support such education efforts via funding, public speaking opportunities, Web presence, publishing, workshops, prizes, opportunities to discuss curriculum design, and support of mentorship and other means of sustained communication among communities of scholars. Such programs have been critical to the broad expansion of the range and visibility of research and educational activities in mathematical biology. Read More

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http://dx.doi.org/10.1007/s11538-020-00728-9DOI Listing

Coupling the Macroscale to the Microscale in a Spatiotemporal Context to Examine Effects of Spatial Diffusion on Disease Transmission.

Bull Math Biol 2020 May 10;82(5):58. Epub 2020 May 10.

College of Mathematics and Information Science, Shaanxi Normal University, Xi'an, 710062, People's Republic of China.

There are many challenges to coupling the macroscale to the microscale in temporal or spatial contexts. In order to examine effects of an individual movement and spatial control measures on a disease outbreak, we developed a multiscale model and extended the semi-stochastic simulation method by linking individual movements to pathogen's diffusion, linking the slow dynamics for disease transmission at the population level to the fast dynamics for pathogen shedding/excretion at the individual level. Numerical simulations indicate that during a disease outbreak individuals with the same infection status show the property of clustering and, in particular, individuals' rapid movements lead to an increase in the average reproduction number [Formula: see text], the final size and the peak value of the outbreak. Read More

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http://dx.doi.org/10.1007/s11538-020-00736-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7222150PMC

Persistence and Oscillations of Plant-Pollinator-Herbivore Systems.

Bull Math Biol 2020 May 8;82(5):57. Epub 2020 May 8.

School of Mathematics, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China.

This paper considers plant-pollinator-herbivore systems where the plant produces food for the pollinator, the pollinator provides pollination service for the plant in return, while the herbivore consumes both the food and the plant itself without providing pollination service. Based on these resource-consumer interactions, we form a plant-pollinator-herbivore model which includes the intermediary food. Using qualitative method and Kuznetsov theorem, we show global dynamics of the subsystems, uniform persistence of the whole system and periodic oscillation by Hopf bifurcation. Read More

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http://dx.doi.org/10.1007/s11538-020-00735-wDOI Listing

Modeling Stripe Formation on Growing Zebrafish Tailfins.

Bull Math Biol 2020 Apr 30;82(5):56. Epub 2020 Apr 30.

Division of Applied Mathematics, Brown University, Providence, RI, USA.

As zebrafish develop, black and gold stripes form across their skin due to the interactions of brightly colored pigment cells. These characteristic patterns emerge on the growing fish body, as well as on the anal and caudal fins. While wild-type stripes form parallel to a horizontal marker on the body, patterns on the tailfin gradually extend distally outward. Read More

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http://dx.doi.org/10.1007/s11538-020-00731-0DOI Listing

A Mathematical Framework for Predicting Lifestyles of Viral Pathogens.

Authors:
Alexander Lange

Bull Math Biol 2020 Apr 29;82(5):54. Epub 2020 Apr 29.

Department of Applied Biosciences and Process Engineering, HS Anhalt, Köthen, Germany.

Despite being similar in structure, functioning, and size, viral pathogens enjoy very different, usually well-defined ways of life. They occupy their hosts for a few days (influenza), for a few weeks (measles), or even lifelong (HCV), which manifests in acute or chronic infections. The various transmission routes (airborne, via direct physical contact, etc. Read More

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http://dx.doi.org/10.1007/s11538-020-00730-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7189636PMC

Noise-Induced Transitions in a Nonsmooth Producer-Grazer Model with Stoichiometric Constraints.

Bull Math Biol 2020 Apr 29;82(5):55. Epub 2020 Apr 29.

Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, T6G 2G1, Canada.

Stoichiometric producer-grazer models are nonsmooth due to the Liebig's Law of Minimum and can generate new dynamics such as bistability for producer-grazer interactions. Environmental noises can be extremely important and change dynamical behaviors of a stoichiometric producer-grazer model. In this paper, we consider a stochastically forced producer-grazer model and study the phenomena of noise-induced state switching between two stochastic attractors in the bistable zone. Read More

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http://dx.doi.org/10.1007/s11538-020-00733-yDOI Listing

Spreading Speed in an Integrodifference Predator-Prey System without Comparison Principle.

Bull Math Biol 2020 Apr 20;82(5):53. Epub 2020 Apr 20.

Department of Mathematics, University of Miami, Coral Gables, FL, 33146, USA.

In this paper, we study the spreading speed in an integrodifference system which models invasion of predators into the habitat of the prey. Without the requirement of comparison principle, we construct several auxiliary integrodifference equations and use the results of monotone scalar equations to estimate the spreading speed of the invading predators. We also present some numerical simulations to support our theoretical results and demonstrate that the integrodifference predator-prey system exhibits very complex dynamics. Read More

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http://dx.doi.org/10.1007/s11538-020-00725-yDOI Listing

Commentary on Ferguson, et al., "Impact of Non-pharmaceutical Interventions (NPIs) to Reduce COVID-19 Mortality and Healthcare Demand".

Bull Math Biol 2020 04 8;82(4):52. Epub 2020 Apr 8.

Biocomplexity Institute and Initiative, University of Virginia, Charlottesville, USA.

A recent manuscript (Ferguson et al. in Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand, Imperial College COVID-19 Response Team, London, 2020. https://www. Read More

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http://dx.doi.org/10.1007/s11538-020-00726-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7140590PMC

Stationary Pattern of a Reaction-Diffusion Mussel-Algae Model.

Bull Math Biol 2020 Apr 8;82(4):51. Epub 2020 Apr 8.

School of Mathematics, Harbin Institute of Technology, Harbin, 150001, Heilongjiang, People's Republic of China.

In this paper, we consider a reaction-diffusion mussel-algae model with state-dependent mussel mortality. This mortality involves a positive feedback term resulting from the reduction of dislodgment and predation and a negative feedback term resulting from the intraspecific competition for mussel. We first study the global stability of the nonnegative uniform steady states and then focus on the existence and nonexistence of nonconstant positive steady states. Read More

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http://dx.doi.org/10.1007/s11538-020-00727-wDOI Listing

Adaptive Bet-Hedging Revisited: Considerations of Risk and Time Horizon.

Bull Math Biol 2020 Apr 4;82(4):50. Epub 2020 Apr 4.

Max Planck Institute for Mathematics in the Sciences, Inselstrasse 22, 04103, Leipzig, Germany.

Models of adaptive bet-hedging commonly adopt insights from Kelly's famous work on optimal gambling strategies and the financial value of information. In particular, such models seek evolutionary solutions that maximize long-term average growth rate of lineages, even in the face of highly stochastic growth trajectories. Here, we argue for extensive departures from the standard approach to better account for evolutionary contingencies. Read More

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http://dx.doi.org/10.1007/s11538-020-00729-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7128013PMC

The Impact of Elastic Deformations of the Extracellular Matrix on Cell Migration.

Bull Math Biol 2020 Apr 4;82(4):49. Epub 2020 Apr 4.

Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, 412 96, Gothenburg, Sweden.

The mechanical properties of the extracellular matrix, in particular its stiffness, are known to impact cell migration. In this paper, we develop a mathematical model of a single cell migrating on an elastic matrix, which accounts for the deformation of the matrix induced by forces exerted by the cell, and investigate how the stiffness impacts the direction and speed of migration. We model a cell in 1D as a nucleus connected to a number of adhesion sites through elastic springs. Read More

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http://dx.doi.org/10.1007/s11538-020-00721-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7128007PMC

Circular Tessera Codes in the Evolution of the Genetic Code.

Bull Math Biol 2020 Apr 4;82(4):48. Epub 2020 Apr 4.

Institute of Mathematical Biology, Faculty for Computer Sciences, Mannheim University of Applied Sciences, 68163, Mannheim, Germany.

The origin of the modern genetic code and the mechanisms that have contributed to its present form raise many questions. The main goal of this work is to test two hypotheses concerning the development of the genetic code for their compatibility and complementarity and see if they could benefit from each other. On the one hand, Gonzalez, Giannerini and Rosa developed a theory, based on four-based codons, which they called tesserae. Read More

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http://dx.doi.org/10.1007/s11538-020-00724-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7128014PMC

Mathematical Analysis of the Ross-Macdonald Model with Quarantine.

Bull Math Biol 2020 Apr 2;82(4):47. Epub 2020 Apr 2.

Department of Mathematics, Shanghai Normal University, 200234, Shanghai, China.

People infected with malaria may receive less mosquito bites when they are treated in well-equipped hospitals or follow doctors' advice for reducing exposure to mosquitoes at home. This quarantine-like intervention measure is especially feasible in countries and areas approaching malaria elimination. Motivated by mathematical models with quarantine for directly transmitted diseases, we develop a mosquito-borne disease model where imperfect quarantine is considered to mitigate the disease transmission from infected humans to susceptible mosquitoes. Read More

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http://dx.doi.org/10.1007/s11538-020-00723-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7117789PMC

Dynamic Analysis of the Time-Delayed Genetic Regulatory Network Between Two Auto-Regulated and Mutually Inhibitory Genes.

Bull Math Biol 2020 Mar 31;82(4):46. Epub 2020 Mar 31.

Biological Sciences Department, The University of Texas at Dallas, Richardson, TX, 75080, USA.

Time delays play important roles in genetic regulatory networks. In this paper, a gene regulatory network model with time delays and mutual inhibition is considered, where time delays are regarded as bifurcation parameters. In the first part of this paper, we analyze the associated characteristic equations and obtain the conditions for the stability of the system and the existence of Hopf bifurcations in five special cases. Read More

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http://dx.doi.org/10.1007/s11538-020-00722-1DOI Listing
March 2020
1.389 Impact Factor

Mechanisms and Points of Control in the Spread of Inflammation: A Mathematical Investigation.

Bull Math Biol 2020 Mar 28;82(4):45. Epub 2020 Mar 28.

Department of Physics and Mathematics, Nottingham Trent University, Clifton Campus, Nottingham, NG11 8NS, UK.

Understanding the mechanisms that control the body's response to inflammation is of key importance, due to its involvement in myriad medical conditions, including cancer, arthritis, Alzheimer's disease and asthma. While resolving inflammation has historically been considered a passive process, since the turn of the century the hunt for novel therapeutic interventions has begun to focus upon active manipulation of constituent mechanisms, particularly involving the roles of apoptosing neutrophils, phagocytosing macrophages and anti-inflammatory mediators. Moreover, there is growing interest in how inflammatory damage can spread spatially due to the motility of inflammatory mediators and immune cells. Read More

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http://dx.doi.org/10.1007/s11538-020-00709-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7103018PMC

Coloured Noise from Stochastic Inflows in Reaction-Diffusion Systems.

Bull Math Biol 2020 Mar 20;82(4):44. Epub 2020 Mar 20.

Cardiff School of Mathematics, Cardiff University, Cardiff, UK.

In this paper, we present a framework for investigating coloured noise in reaction-diffusion systems. We start by considering a deterministic reaction-diffusion equation and show how external forcing can cause temporally correlated or coloured noise. Here, the main source of external noise is considered to be fluctuations in the parameter values representing the inflow of particles to the system. Read More

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http://dx.doi.org/10.1007/s11538-020-00719-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7083815PMC

Speed Switch in Glioblastoma Growth Rate due to Enhanced Hypoxia-Induced Migration.

Bull Math Biol 2020 Mar 16;82(3):43. Epub 2020 Mar 16.

School of Mathematical Sciences, University of Nottingham, Nottingham, UK.

We analyze the wave speed of the Proliferation Invasion Hypoxia Necrosis Angiogenesis (PIHNA) model that was previously created and applied to simulate the growth and spread of glioblastoma (GBM), a particularly aggressive primary brain tumor. We extend the PIHNA model by allowing for different hypoxic and normoxic cell migration rates and study the impact of these differences on the wave-speed dynamics. Through this analysis, we find key variables that drive the outward growth of the simulated GBM. Read More

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http://dx.doi.org/10.1007/s11538-020-00718-xDOI Listing

An Epidemiological Model of Malaria Accounting for Asymptomatic Carriers.

Bull Math Biol 2020 Mar 14;82(3):42. Epub 2020 Mar 14.

Department of Mathematics, University of Texas at San Antonio, San Antonio, TX, 78249, USA.

Asymptomatic individuals in the context of malarial disease are subjects who carry a parasite load, but do not show clinical symptoms. A correct understanding of the influence of asymptomatic individuals on transmission dynamics will provide a comprehensive description of the complex interplay between the definitive host (female Anopheles mosquito), intermediate host (human), and agent (Plasmodium parasite). The goal of this article is to conduct a rigorous mathematical analysis of a new compartmentalized malaria model accounting for asymptomatic human hosts for the purpose of calculating the basic reproductive number ([Formula: see text]) and determining the bifurcations that might occur at the onset of disease-free equilibrium. Read More

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http://dx.doi.org/10.1007/s11538-020-00717-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072066PMC

Decoys and Dilution: The Impact of Incompetent Hosts on Prevalence of Chagas Disease.

Bull Math Biol 2020 Mar 13;82(3):41. Epub 2020 Mar 13.

Department of Mathematics, University of Texas at Arlington, Arlington, TX, 76019, USA.

Biodiversity is commonly believed to reduce risk of vector-borne zoonoses. However, researchers already showed that the effect of biodiversity on disease transmission is not that straightforward. This study focuses on the effect of biodiversity, specifically on the effect of the decoy process (additional hosts distracting vectors from their focal host), on reducing infections of vector-borne diseases in humans. Read More

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http://dx.doi.org/10.1007/s11538-020-00710-5DOI Listing

A Dimensionally Reduced Model of Biofilm Growth Within a Flow Cell.

Bull Math Biol 2020 Mar 13;82(3):40. Epub 2020 Mar 13.

Engineering Sciences and Applied Mathematics, Northwestern University, Technological Institute, 2145 Sheridan Rd., Evanston, IL, 60208-3125, USA.

Biofilms are colonies of bacteria attached to surfaces. They play a critical role in many engineering and medical applications. Scientists study biofilm growth in flow cells but often have limited direct knowledge of the environmental conditions in the apparatus. Read More

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http://dx.doi.org/10.1007/s11538-020-00715-0DOI Listing

Complex Far-Field Geometries Determine the Stability of Solid Tumor Growth with Chemotaxis.

Bull Math Biol 2020 Mar 12;82(3):39. Epub 2020 Mar 12.

Department of Applied Mathematics, Illinois Institute of Technology, Chicago, IL, 60616, USA.

In this paper, we develop a sharp interface tumor growth model to study the effect of the tumor microenvironment using a complex far-field geometry that mimics a heterogeneous distribution of vasculature. Together with different nutrient uptake rates inside and outside the tumor, this introduces variability in spatial diffusion gradients. Linear stability analysis suggests that the uptake rate in the tumor microenvironment, together with chemotaxis, may induce unstable growth, especially when the nutrient gradients are large. Read More

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http://dx.doi.org/10.1007/s11538-020-00716-zDOI Listing

A Multicellular Model of Primary Saliva Secretion in the Parotid Gland.

Bull Math Biol 2020 Mar 11;82(3):38. Epub 2020 Mar 11.

Department of Mathematics, The University of Auckland, Level 2, Building 303, 38 Princes Street, Auckland CBD, New Zealand.

We construct a three-dimensional anatomically accurate multicellular model of a parotid gland acinus to investigate the influence that the topology of its lumen has on primary fluid secretion. Our model consists of seven individual cells, coupled via a common lumen and intercellular signalling. Each cell is equipped with the intracellular calcium ([Formula: see text])-signalling model developed by Pages et al, Bull Math Biol 81: 1394-1426, 2019. Read More

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http://dx.doi.org/10.1007/s11538-020-00712-3DOI Listing

A Note on Observation Processes in Epidemic Models.

Bull Math Biol 2020 Mar 7;82(3):37. Epub 2020 Mar 7.

Department of Mathematics and Statistics, McMaster University, Hamilton, ON, Canada.

Many disease models focus on characterizing the underlying transmission mechanism but make simple, possibly naive assumptions about how infections are reported. In this note, we use a simple deterministic Susceptible-Infected-Removed (SIR) model to compare two common assumptions about disease incidence reports: Individuals can report their infection as soon as they become infected or as soon as they recover. We show that incorrect assumptions about the underlying observation processes can bias estimates of the basic reproduction number and lead to overly narrow confidence intervals. Read More

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http://dx.doi.org/10.1007/s11538-020-00713-2DOI Listing

An Asymptotic Analysis of the Malonyl-CoA Route to 3-Hydroxypropionic Acid in Genetically Engineered Microbes.

Bull Math Biol 2020 Mar 6;82(3):36. Epub 2020 Mar 6.

Synthetic Biology Research Centre, University of Nottingham, Nottingham, NG7 2RD, UK.

There has been recent interest in creating an efficient microbial production route for 3-hydroxypropionic acid, an important platform chemical. We develop and solve a mathematical model for the time-dependent metabolite concentrations in the malonyl-CoA pathway for 3-hydroxypropionic acid production in microbes, using a combination of numerical and asymptotic methods. This allows us to identify the most important targets for enzyme regulation therein under conditions of plentiful and sparse pyruvate, and to quantify their relative importance. Read More

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http://dx.doi.org/10.1007/s11538-020-00714-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7058581PMC