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Mathematical Biosciences

Valeria Mamouridis, Nadja Klein, Thomas Kneib, Carmen Cadarso Suarez, Francesc Maynou
We analysed the landings per unit effort (LPUE) from the Barcelona trawl fleet targeting the red shrimp (Aristeus antennatus) using novel Bayesian structured additive distributional regression to gain a better understanding of the dynamics and determinants of variation in LPUE. The data set, covering a time span of 17 years, includes fleet-dependent variables (e.g. the number of trips performed by vessels), temporal variables (inter- and intra-annual variability) and environmental variables (the North Atlantic Oscillation index)...
November 30, 2016: Mathematical Biosciences
M Leguèbe, M G Notarangelo, M Twarogowska, R Natalini, C Poignard
We propose a mathematical model for the transport of DNA plasmids from the extracellular matrix up to the cell nucleus. The model couples two phenomena: the electroporation process, describing the cell membrane permeabilization to plasmids and the intracellular transport enhanced by the presence of microtubules. Numerical simulations of cells with arbitrary geometry, in 2D and 3D, and a network of microtubules show numerically the importance of the microtubules and the electroporation on the effectiveness of the DNA transfection, as observed by previous biological data...
November 30, 2016: Mathematical Biosciences
Dharmendra Tripathi, Ashu Yadav, O Anwar Bég
Analytical solutions are developed for the electro-kinetic flow of a viscoelastic biological liquid in a finite length cylindrical capillary geometry under peristaltic waves. The Jefferys' non-Newtonian constitutive model is employed to characterize rheological properties of the fluid. The unsteady conservation equations for mass and momentum with electro-kinetic and Darcian porous medium drag force terms are reduced to a system of steady linearized conservation equations in an axisymmetric coordinate system...
November 29, 2016: Mathematical Biosciences
Sanhong Liu, Shigui Ruan, Xinan Zhang
Avian influenza is a zoonotic disease caused by the transmission of the avian influenza A virus, such as H5N1 and H7N9, from birds to humans. The avian influenza A H5N1 virus has caused more than 500 human infections worldwide with nearly a 60% death rate since it was first reported in Hong Kong in 1997. The four outbreaks of the avian influenza A H7N9 in China from March 2013 to June 2016 have resulted in 580 human cases including 202 deaths with a death rate of nearly 35%. In this paper, we construct two avian influenza bird-to-human transmission models with different growth laws of the avian population, one with logistic growth and the other with Allee effect, and analyze their dynamical behavior...
November 23, 2016: Mathematical Biosciences
Tanmay Pal, Pranab Kumar Dutta, Srinivasu Maka
A generalized framework for the generation of Periodic Breathing (PB), caused by delay variation, hypocapnia and sleep along with its management with oxygen therapy is presented. For this, a minimal model of respiratory regulation with cardiovascular component and two delays is proposed. This model is linearized and analyzed for stability by the proposed algorithms using Lyapunov-Krasovskii functional. Oscillation in this model is produced by the increase of delays, an increase of chemoreceptor gains (hypocapnia) and a decrease in minute ventilation (sleep induced PB)...
November 21, 2016: Mathematical Biosciences
Sara I Abdelsalam, Kambiz Vafai
This work is concerned with theoretically investigating the pulsatile flow of a fluid with suspended particles in a flow driven by peristaltic waves that deform the wall of a small blood artery in the shape of traveling sinusoidal waves with constant velocity. The problem formulation in the wave frame of reference is presented and the governing equations are developed up to the second-order in terms of the asymptotic expansion of Womersley number which characterizes the unsteady effect in the wave frame. We suppose that the flow rate imposed, in this frame, is a function versus time...
November 16, 2016: Mathematical Biosciences
Daniel Goeleven
Spitting spiders (Scytodes sp.) spit a mixture of silk and glue at their prey during attack. In this note, we show that a nonsmooth oscillator can be used as a biomechanical model to describe the zig-zag patterns produced by the spit of the spider Scytodes thoracica.
November 12, 2016: Mathematical Biosciences
A Rahbari, M Fakour, A Hamzehnezhad, M Akbari Vakilabadi, D D Ganji
In the present study, the analytical study on blood flow containing nanoparticles through porous blood vessels is done in presence of magnetic field using Homotopy Perturbation Method (HPM). Blood is considered as the third grade non- Newtonian fluid containing nanoparticles. Viscosity of nanofluid is determined by Constant, Reynolds' and Vogel's models. Some efforts have been made to show the reliability and performance of the present method compared with the numerical method, Runge-Kutta fourth-order. The results reveal that the HPM can achieve suitable results in predicting the solution of these problems...
November 11, 2016: Mathematical Biosciences
José A Ferreira, Lino Gonçalves, Jahed Naghipoor, Paula de Oliveira, Timon Rabczuk
In this paper the effect of plaque composition, on the accumulation of drug released by a drug eluting stent, is analyzed. The mathematical model is represented by two coupled systems of partial differential equations that describe the pharmacokinetics of drug in the stent coating and in the arterial wall. The influence of the stiffness and porosity of soft and hard plaques is studied. A case study based on optical coherence tomography images is also included.
November 10, 2016: Mathematical Biosciences
Robert Stephen Cantrell, Chris Cosner, Yuan Lou, Sebastian J Schreiber
Understanding the evolution of dispersal is an important issue in evolutionary ecology. For continuous time models in which individuals disperse throughout their lifetime, it has been shown that a balanced dispersal strategy, which results in an ideal free distribution, is evolutionary stable in spatially varying but temporally constant environments. Many species, however, primarily disperse prior to reproduction (natal dispersal) and less commonly between reproductive events (breeding dispersal). These species include territorial species such as birds and reef fish, and sessile species such as plants, and mollusks...
November 10, 2016: Mathematical Biosciences
Morten Gram Pedersen, Alessia Tagliavini, Giuliana Cortese, Michela Riz, Francesco Montefusco
Most endocrine cells secrete hormones as a result of Ca(2+)-regulated exocytosis, i.e., fusion of the membranes of hormone-containing secretory granules with the cell membrane, which allows the hormone molecules to escape to the extracellular space. As in neurons, electrical activity and cell depolarization open voltage-sensitive Ca(2+) channels, and the resulting Ca(2+) influx elevate the intracellular Ca(2+) concentration, which in turn causes exocytosis. Whereas the main molecular components involved in exocytosis are increasingly well understood, quantitative understanding of the dynamical aspects of exocytosis is still lacking...
November 9, 2016: Mathematical Biosciences
N Chatzistefani, M J Chappell, C Hutchinson, S Kletzenbauer, N D Evans
The purpose of this study is to acquire mechanistic knowledge of the gastrocnemius muscle-Achilles tendon complex behaviour during specific movements in humans through mathematical modelling. Analysis of this muscle-tendon complex was performed to see if already existing muscle-tendon models of other parts of the body could be applied to the leg muscles, especially the gastrocnemius muscle-Achilles tendon complex, and whether they could adequately characterise its behaviour. Five healthy volunteers were asked to take part in experiments where dorsiflexion and plantar flexion of the foot were studied...
November 8, 2016: Mathematical Biosciences
F B Agusto
The Ebola virus disease is caused by the Ebola virus which belongs to the filoviridae virus family. The 2014 outbreaks were estimated to have caused over 11,000 fatalities. In this paper, we formulate and analyze a system of ordinary differential equations which incorporates disease relapse and reinfection. The Ebola model with disease relapse and reinfection is locally-asymptotically stable when the basic reproduction number is less than unity. The model exhibits in the presence of disease reinfection, the phenomenon of backward bifurcation, where the stable disease-free equilibrium co-exists with a stable endemic equilibrium when the associated reproduction number is less than unity...
November 8, 2016: Mathematical Biosciences
Logan Ward, Mical Paul, Steen Andreassen
The aim of this paper is to apply machine learning as a method to refine a manually constructed CPN for the assessment of the severity of the systemic inflammatory response syndrome (SIRS).The goal of tuning the CPN is to create a scoring system that uses only objective data, compares favourably with other severity-scoring systems and differentiates between sepsis and non-infectious SIRS. The resulting model, the Learned-Age (LA) -Sepsis CPN has good discriminatory ability for the prediction of 30-day mortality with an area under the ROC curve of 0...
November 8, 2016: Mathematical Biosciences
Seyed Ali Madani Tonekaboni, Andrew Dhawan, Mohammad Kohandel
The cancer stem cell (CSC) hypothesis suggests that cancer stem cells proliferate via a hierarchical model of unidirectional differentiation. However, growing experimental evidence has advanced this hypothesis by introducing a bidirectional hierarchy, in which non-CSCs may dedifferentiate into CSCs. Various models have been developed enabling the incorporation of this plasticity within cancer cell populations, focusing on behaviour in the limit of a large number of cells. However, stochastic effects predominate in the limit of small numbers of cells, which correlates with biologically relevant assays such as the mammosphere formation assay (MFA)...
November 8, 2016: Mathematical Biosciences
Vladimir P Zhdanov
Although the transcriptional regulation of gene expression has been a subject of intense experimental and theoretical studies over the past several decades, the understanding of this process is still incomplete. In particular, the models focused on the function of transcription factors usually take into account only the lateral interactions between them in the ground bound state. The rates of attachment and detachment of transcription factors on the promoter sites depend, however, also on the lateral interactions in the activated state...
November 8, 2016: Mathematical Biosciences
Carlene Perpetua P Arceo, Editha C Jose, Angelyn R Lao, Eduardo R Mendoza
This paper further develops the connection between Chemical Reaction Network Theory (CRNT) and Biochemical Systems Theory (BST) that we recently introduced [1]. We first use algebraic properties of kinetic sets to study the set of complex factorizable kinetics CFK(N) on a CRN, which shares many characteristics with its subset of mass action kinetics. In particular, we extend the Theorem of Feinberg-Horn [9] on the coincidence of the kinetic and stoichiometric subsets of a mass action system to CF kinetics, using the concept of span surjectivity...
November 4, 2016: Mathematical Biosciences
Elisabeth O Bangsgaard, Johnny T Ottesen
A novel model of the hypothalamic-pituitary-adrenal axis is presented. The axis is an endocrine system responsible for coping with stress and it is likely to be involved in depression. The dynamics of the system is studied and existence, uniqueness and positivity of the solution and the existence of an attracting trapping region are proved. The model is calibrated and compared to data for healthy and depressed subjects. A sensitivity analysis resulting in a set of identifiable physiological parameters is provided...
November 2, 2016: Mathematical Biosciences
N L González Morales, M Núñez-López, J Ramos-Castañeda, J X Velasco-Hernández
In this work we present a mathematical model that incorporates two Dengue serotypes. The model has been constructed to study both the epidemiological trends of the disease and conditions that allow coexistence in competing strains under vaccination. We consider two viral strains and temporary cross-immunity with one vector mosquito population. Results suggest that vaccination scenarios will not only reduce disease incidence but will also modify the transmission dynamics. Indeed, vaccination and cross immunity period are seen to decrease the frequency and magnitude of outbreaks but in a differentiated manner with specific effects depending upon the interaction vaccine and strain type...
October 20, 2016: Mathematical Biosciences
Tina M Mitre, Massimo Pietropaolo, Anmar Khadra
The expression level of tissue-restricted autoantigens (TSA) in the thymus is crucial for the negative selection of autoreactive T cells during central tolerance. The autoimmune regulator factor (AIRE) plays an important role in the positive regulation of these TSA in medullary thymic epithelial cells and, consequently, in the negative selection of high-avidity autoreactive T cells. Recent studies, however, revealed that thymic islet cell autoantigen (ICA69) expression level in non-obese diabetic (NOD) mice, prone to developing type 1 diabetes (T1D), is reduced due to an increase in the binding affinity of AIRE to the Ica1-promoter region, which regulates ICA69 protein synthesis...
October 17, 2016: Mathematical Biosciences
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