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Mathematical model

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https://www.readbyqxmd.com/read/29161271/a-mathematical-function-for-the-description-of-nutrient-response-curve
#1
Hamed Ahmadi
Several mathematical equations have been proposed to modeling nutrient-response curve for animal and human justified on the goodness of fit and/or on the biological mechanism. In this paper, a functional form of a generalized quantitative model based on Rayleigh distribution principle for description of nutrient-response phenomena is derived. The three parameters governing the curve a) has biological interpretation, b) may be used to calculate reliable estimates of nutrient response relationships, and c) provide the basis for deriving relationships between nutrient and physiological responses...
2017: PloS One
https://www.readbyqxmd.com/read/29161259/the-us-president-s-malaria-initiative-plasmodium-falciparum-transmission-and-mortality-a-modelling-study
#2
Peter Winskill, Hannah C Slater, Jamie T Griffin, Azra C Ghani, Patrick G T Walker
BACKGROUND: Although significant progress has been made in reducing malaria transmission globally in recent years, a large number of people remain at risk and hence the gains made are fragile. Funding lags well behind amounts needed to protect all those at risk and ongoing contributions from major donors, such as the President's Malaria Initiative (PMI), are vital to maintain progress and pursue further reductions in burden. We use a mathematical modelling approach to estimate the impact of PMI investments to date in reducing malaria burden and to explore the potential negative impact on malaria burden should a proposed 44% reduction in PMI funding occur...
November 2017: PLoS Medicine
https://www.readbyqxmd.com/read/29161187/network-mapping-with-gimme
#3
Adriene M Beltz, Kathleen M Gates
Network science is booming! While the insights and images afforded by network mapping techniques are compelling, implementing the techniques is often daunting to researchers. Thus, the aim of this tutorial is to facilitate implementation in the context of GIMME, or group iterative multiple model estimation. GIMME is an automated network analysis approach for intensive longitudinal data. It creates person-specific networks that explain how variables are related in a system. The relations can signify current or future prediction that is common across people or applicable only to an individual...
November 2017: Multivariate Behavioral Research
https://www.readbyqxmd.com/read/29160885/drying-kinetics-of-water-droplets-stabilized-by-surfactant-molecules-or-solid-particles-in-a-thin-non-volatile-oil-layer
#4
Hayato Miyazaki, Susumu Inasawa
We have investigated drying of water droplets stabilized by solid particles or surfactant molecules in a thin oil layer. The surfactant-stabilized droplets isotropically shrink, whereas the droplets stabilized by spherical particles severely deform during drying because of buckling of the particulate shells. However, buckling of the shells hardly affects droplet drying. The drying times for complete evaporation are almost the same for water droplets with the same initial diameter and the drying time is independent of the type of surface stabilizer (particles or surfactant)...
November 21, 2017: Soft Matter
https://www.readbyqxmd.com/read/29159807/experimental-investigation-of-gafchromic-%C3%A2-ebt3-intrinsic-energy-dependence-with-kilovoltage-x-rays-137-cs-and-60-co
#5
Cliff G Hammer, Benjamin Saul Rosen, Jessica M Fagerstrom, Wesley S Culberson, Larry A DeWerd
PURPOSE: To determine experimentally the intrinsic energy response, kbq , of EBT3 GafChromic(®) radiochromic film with kilovoltage x-rays,(137) Cs, and (60) Co in therapeutic and diagnostic dose ranges through direct measurement with an accompanying mathematical approach to describe the physical processes involved. METHODS: EBT3 film was irradiated to known doses using (60) Co, (137) Cs, and 13 NIST-matched kilovoltage x-ray beams. Seven dose levels, ranging from 57 to 7002 mGy, were chosen for this work...
November 21, 2017: Medical Physics
https://www.readbyqxmd.com/read/29159570/multi-timescale-analysis-of-a-metabolic-network-in-synthetic-biology-a-kinetic-model-for-3-hydroxypropionic-acid-production-via-beta-alanine
#6
Mohit P Dalwadi, John R King, Nigel P Minton
A biosustainable production route for 3-hydroxypropionic acid (3HP), an important platform chemical, would allow 3HP to be produced without using fossil fuels. We are interested in investigating a potential biochemical route to 3HP from pyruvate through [Formula: see text]-alanine and, in this paper, we develop and solve a mathematical model for the reaction kinetics of the metabolites involved in this pathway. We consider two limiting cases, one where the levels of pyruvate are never replenished, the other where the levels of pyruvate are continuously replenished and thus kept constant...
November 20, 2017: Journal of Mathematical Biology
https://www.readbyqxmd.com/read/29159532/a-multiphysics-approach-for-modeling-early-atherosclerosis
#7
M P Thon, A Hemmler, A Glinzer, M Mayr, M Wildgruber, A Zernecke-Madsen, M W Gee
This work is devoted to the development of a mathematical model of the early stages of atherosclerosis incorporating processes of all time scales of the disease and to show their interactions. The cardiovascular mechanics is modeled by a fluid-structure interaction approach coupling a non-Newtonian fluid to a hyperelastic solid undergoing anisotropic growth and a change of its constitutive equation. Additionally, the transport of low-density lipoproteins and its penetration through the endothelium is considered by a coupled set of advection-diffusion-reaction equations...
November 20, 2017: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/29159223/programs-for-the-calculation-of-the-spinodal-decomposition-growth-rate-and-the-spinodal-gap-in-nanoparticles
#8
Evgeny Pogorelov, Julia Kundin
This data article contains the programs for the calculation of the spinodal decomposition growth rate and for the modeling of the spinodal gap and concentration profiles in nanoparticles which were used in our article (Pogorelov et al., 2017) [1]. The modeling is based on the mathematical model of spinodal phase decomposition with intercalation rate conditions on the boundaries (Singh et al., 2008) [2]. The maximal growth rate and the parameters of the concentration wave function can be evaluated for a fixed mean composition and intercalation rate...
December 2017: Data in Brief
https://www.readbyqxmd.com/read/29158608/a-fully-coupled-space-time-multiscale-modeling-framework-for-predicting-tumor-growth
#9
Mohammad Mamunur Rahman, Yusheng Feng, Thomas E Yankeelov, J Tinsley Oden
Most biological systems encountered in living organisms involve highly complex heterogeneous multi-component structures that exhibit different physical, chemical, and biological behavior at different spatial and temporal scales. The development of predictive mathematical and computational models of multiscale events in such systems is a major challenge in contemporary computational biomechanics, particularly the development of models of growing tumors in humans. The aim of this study is to develop a general framework for tumor growth prediction by considering major biological events at tissue, cellular, and subcellular scales...
June 15, 2017: Computer Methods in Applied Mechanics and Engineering
https://www.readbyqxmd.com/read/29158597/a-new-paradigm-in-modelling-the-evolution-of-a-stand-via-the-distribution-of-tree-sizes
#10
Petras Rupšys, Edmundas Petrauskas
Our study focusses on investigating a modern modelling paradigm, a bivariate stochastic process, that allows us to link individual tree variables with growth and yield stand attributes. In this paper, our aim is to introduce the mathematics of mixed effect parameters in a bivariate stochastic differential equation and to describe how such a model can be used to aid our understanding of the bivariate height and diameter distribution in a stand using a large dataset provided by the Lithuanian National Forest Inventory (LNFI)...
November 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29158230/neoantigen-quality-predicts-immune-response-survival
#11
(no author information available yet)
A new mathematical model finds that tumor neoantigen quality trumps quantity when it comes to predicting response to immunotherapy and the likelihood of long-term survival among patients with cancer.
November 20, 2017: Cancer Discovery
https://www.readbyqxmd.com/read/29158122/biomarkers-distinguish-hbeag-seroconverted-from-non-converted-individuals-in-chronic-hepatitis-b-patients-treated-with-a-therapeutic-vaccine
#12
Xian Zhou, Shuang Geng, Shijie Zhang, Weidong Zhao, Gan Zhao, Yumei Wen, Xuanyi Wang, Bin Wang
Cytokine assays of host immune responses to vaccination can indicate vaccine efficacy. Here we tested the hypothesis that assays of the cytokine status of infected individuals prior to therapeutic vaccination might provide a guide to vaccine therapeutic efficacy. If so, cytokine analysis might be used to select appropriate patients for therapeutic vaccination. Data were obtained from a panel of 14 cytokine/chemokine assays that were done during a phase III clinical trial of HBsAg-HBIG therapeutic vaccine (YIC) treatment of chronic hepatitis B (CHB) patients...
November 17, 2017: Cytokine
https://www.readbyqxmd.com/read/29157914/population-sensitivities-of-animals-to-chronic-ionizing-radiation-model-predictions-from-mice-to-elephant
#13
Tatiana G Sazykina
Model predictions of population response to chronic ionizing radiation (endpoint 'morbidity') were made for 11 species of warm-blooded animals, differing in body mass and lifespan - from mice to elephant. Predictions were made also for 3 bird species (duck, pigeon, and house sparrow). Calculations were based on analytical solutions of the mathematical model, simulating a population response to low-LET ionizing radiation in an ecosystem with a limiting resource (Sazykina, Kryshev, 2016). Model parameters for different species were taken from biological and radioecological databases; allometric relationships were employed for estimating some parameter values...
November 17, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/29157654/an-innovative-lung-model-for-multiple-breath-washout-testing-in-health-and-disease
#14
Pinelopi Anagnostopoulou, Sarah Vomsattel, Anne-Christiane Kentgens, Marisa Guidi, Severin Binggeli, Lena Kohler, Florian Singer, Philipp Latzin, Dominik Obrist
BACKGROUND: Multiple breath washout (MBW) is a lung function test that identifies the degree of ventilation inhomogeneity (VI) in the lungs. In vitro validation of MBW devices is recommended. So far, plastic lung models for MBW validation ignored variable degrees of VI. Our primary aim was to create a plastic lung model applicable for physiological lung volumes and variable VI. METHODS: A plastic box divided in two chambers was filled with water and ventilated in various lung volumes and respiratory rates...
November 10, 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/29157456/real-time-deformation-of-human-soft-tissues-a-radial-basis-meshless-3d-model-based-on-marquardt-s-algorithm
#15
Jianyong Zhou, Zu Luo, Chunquan Li, Mi Deng
BACKGROUND: When the meshless method is used to establish the mathematical-mechanical model of human soft tissues, it is necessary to define the space occupied by human tissues as the problem domain and the boundary of the domain as the surface of those tissues. Nodes should be distributed in both the problem domain and on the boundaries. Under external force, the displacement of the node is computed by the meshless method to represent the deformation of biological soft tissues. However, computation by the meshless method consumes too much time, which will affect the simulation of real-time deformation of human tissues in virtual surgery...
January 2018: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/29157366/culling-from-the-actors-perspectives-decision-making-criteria-for-culling-in-qu%C3%A3-bec-dairy-herds-enrolled-in-a-veterinary-preventive-medicine-program
#16
Denis Haine, Roger Cue, Asheber Sewalem, Kevin Wade, René Lacroix, Daniel Lefebvre, Jonathan Rushton, Julie Arsenault, Émile Bouchard, Jocelyn Dubuc
The series of events leading to the decision to cull a cow is complex, involving both individual-level and herd-level factors. While the decision is guided by financial returns, it is also influenced by social and psychological factors. Research studies on the motivational and behavioural aspects of farmers' decision utility are sparse, and nonexistent regarding culling expectations and its decision process. Our goal was to identify shared criteria on culling decisions held by dairy producers and farm advisers, with the help of the Q-methodology...
December 1, 2017: Preventive Veterinary Medicine
https://www.readbyqxmd.com/read/29157236/monitoring-of-nutrient-limitation-in-growing-e-coli-a-mathematical-model-of-a-ppgpp-based-biosensor
#17
Alexandra Pokhilko
BACKGROUND: E. coli can be used as bacterial cell factories for production of biofuels and other useful compounds. The efficient production of the desired products requires careful monitoring of growth conditions and the optimization of metabolic fluxes. To avoid nutrient depletion and maximize product yields we suggest using a natural mechanism for sensing nutrient limitation, related to biosynthesis of an intracellular messenger - guanosine tetraphosphate (ppGpp). RESULTS: We propose a design for a biosensor, which monitors changes in the intracellular concentration of ppGpp by coupling it to a fluorescent output...
November 21, 2017: BMC Systems Biology
https://www.readbyqxmd.com/read/29157229/computer-model-for-the-cardiovascular-system-development-of-an-e-learning-tool-for-teaching-of-medical-students
#18
David Roy Warriner, Martin Bayley, Yubing Shi, Patricia Victoria Lawford, Andrew Narracott, John Fenner
BACKGROUND: This study combined themes in cardiovascular modelling, clinical cardiology and e-learning to create an on-line environment that would assist undergraduate medical students in understanding key physiological and pathophysiological processes in the cardiovascular system. METHODS: An interactive on-line environment was developed incorporating a lumped-parameter mathematical model of the human cardiovascular system. The model outputs were used to characterise the progression of key disease processes and allowed students to classify disease severity with the aim of improving their understanding of abnormal physiology in a clinical context...
November 21, 2017: BMC Medical Education
https://www.readbyqxmd.com/read/29156581/an-enhanced-non-coherent-pre-filter-design-for-tracking-error-estimation-in-gnss-receivers
#19
Zhibin Luo, Jicheng Ding, Lin Zhao, Mouyan Wu
Tracking error estimation is of great importance in global navigation satellite system (GNSS) receivers. Any inaccurate estimation for tracking error will decrease the signal tracking ability of signal tracking loops and the accuracies of position fixing, velocity determination, and timing. Tracking error estimation can be done by traditional discriminator, or Kalman filter-based pre-filter. The pre-filter can be divided into two categories: coherent and non-coherent. This paper focuses on the performance improvements of non-coherent pre-filter...
November 18, 2017: Sensors
https://www.readbyqxmd.com/read/29156567/the-role-of-infected-cell-proliferation-in-the-clearance-of-acute-hbv-infection-in-humans
#20
Ashish Goyal, Ruy M Ribeiro, Alan S Perelson
Around 90-95% of hepatitis B virus (HBV) infected adults do not progress to the chronic phase and, instead, recover naturally. The strengths of the cytolytic and non-cytolytic immune responses are key players that decide the fate of acute HBV infection. In addition, it has been hypothesized that proliferation of infected cells resulting in uninfected progeny and/or cytokine-mediated degradation of covalently closed circular DNA (cccDNA) leading to the cure of infected cells are two major mechanisms assisting the adaptive immune response in the clearance of acute HBV infection in humans...
November 18, 2017: Viruses
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