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Mathematical model

Margit Heiske, Thierry Letellier, Edda Klipp
We developed a mathematical model of oxidative phosphorylation (OXPHOS) that allows for a precise description of mitochondrial function with respect to the respiratory flux and the ATP production. The model reproduced flux-force relationships under various experimental conditions (state 3 and 4, uncoupling, shortage of respiratory substrate) as well as time courses, exhibiting correct P/O ratios. The model was able to reproduce experimental threshold curves for perturbations of the respiratory chain complexes, the F1 F0 -ATP synthase, the ADP/ATP carrier, the phosphate/OH carrier, and the proton leak...
June 24, 2017: FEBS Journal
Bahman Banihashemi
Nine lab-scale continuous flow porous-pot bioreactors operating at various solids retention times and hydraulic retention times were conducted to simulate activated sludge (AS) systems and to evaluate the biodegradation kinetic models for the fate of 17α-ethinylestradiol (EE2), bisphenol-A (BPA), and triclosan (TCS) at the µg/L range. Mathematical models were applied to describe the degradation mechanism of selected microconstituents (MCs) and pseudo second-order model were found to best fit the results when active MCs degraders (XC) were used (r2= 0...
June 16, 2017: Water Environment Research: a Research Publication of the Water Environment Federation
Ulf Träff, Kenny Skagerlund, Linda Olsson, Rickard Östergren
BACKGROUND: Developing sufficient mathematical skills is a prerequisite to function adequately in society today. Given this, an important task is to increase our understanding regarding the cognitive mechanisms underlying young people's acquisition of early number skills and formal mathematical knowledge. AIMS: The purpose was to examine whether the pathways to mathematics model provides a valid account of the cognitive mechanisms underlying symbolic-number processing and mathematics in adolescents...
June 23, 2017: British Journal of Educational Psychology
Marc Garbey, Stefano Casarin, Scott A Berceli
Myocardial infarction is the global leading cause of mortality (Go AS et al. 2014). Coronary artery occlusion is its main etiology and it is commonly treated by Coronary Artery Bypass Graft (CABG) surgery (Wilson CT 2007). The long-term outcome remains unsatisfactory (Benedetto U 2016). The vein faces the phenomenon of restenosis during the post-surgery, which consists of re-occlusion of the lumen and usually requires secondary intervention even within one year after the initial surgery (Harskamp RE 2013). We propose an extensive study of the restenosis phenomenon by implementing two mathematical models previously developed: a heuristic Dynamical System (DS) (Garbey M and Berceli SA 2013), and a stochastic Agent Based Model (ABM) (Garbey M et al...
June 20, 2017: Journal of Theoretical Biology
Diana White, Stéphane Honoré, Florence Hubert
Microtubules (MTs) play a key role in normal cell development and are a primary target for many cancer chemotherapy MT targeting agents (MTAs). As such, understanding MT dynamics in the presence of such agents, as well as other proteins that alter MT dynamics, is extremely important. In general, MTs grow relatively slowly and shorten very fast (almost instantaneously), an event referred to as a catastrophe. These dynamics, referred to as dynamic instability, have been studied in both experimental and theoretical settings...
June 20, 2017: Journal of Theoretical Biology
Lingling Li, Tianhai Tian, Xinan Zhang
Environment factors such as radiation play an important role in the incidence of lung cancer. In spite of substantial efforts in experimental study and mathematical modeling, it is still a significant challenge to estimate lung cancer risk from radiation. To address this issue, we propose a stochastic model to investigate the impact of radiation on the development of lung cancer. The proposed three-stage model with clonal expansion is used to match the data of the male and female patients in the Osaka Cancer Registry (OCR) and Life Span Study (LSS) cohort of atomic bomb survivors in Hiroshima and Nagasaki...
June 20, 2017: Journal of Theoretical Biology
Stéphane Delanaud, Pauline Decima, Amandine Pelletier, Jean-Pierre Libert, Estelle Durand, Erwan Stephan-Blanchard, Véronique Bach, Pierre Tourneux
BACKGROUND: Low-birth-weight (LBW) neonates are nursed in closed incubators to prevent transcutaneous water loss. The RH's impact on the optimal incubator air temperature setting has not been studied. METHODS: On the basis of a clinical cohort study, we modelled all the ambient parameters influencing body heat losses and gains. The algorithm quantifies the change in RH on the air temperature, to maintain optimal thermal conditions in the incubator. RESULTS: Twenty-three neonates (gestational age (GA): 30...
June 20, 2017: Medical Engineering & Physics
Ankit N Khambhati, Ann E Sizemore, Richard F Betzel, Danielle S Bassett
Recent advances in brain imaging techniques, measurement approaches, and storage capacities have provided an unprecedented supply of high temporal resolution neural data. These data present a remarkable opportunity to gain a mechanistic understanding not just of circuit structure, but also of circuit dynamics, and its role in cognition and disease. Such understanding necessitates a description of the raw observations, and a delineation of computational models and mathematical theories that accurately capture fundamental principles behind the observations...
June 20, 2017: NeuroImage
Yu Mi Kang, Chang Hee Jung, Yun Kyung Cho, Jung Eun Jang, Jenie Yoonoo Hwang, Eun Hee Kim, Woo Je Lee, Joong-Yeol Park, Hong-Kyu Kim
OBJECTIVE: Some individuals with metabolically healthy obesity (MHO) convert to metabolically unhealthy obesity (MUO) phenotype, and visceral adiposity is one of proposed mechanisms underlying such conversion. Visceral adipose index (VAI) is a novel mathematical model which estimates visceral adiposity based on anthropometric and lipid profiles. We aimed to determine the association of VAI-estimated visceral adiposity with the MHO-to-MUO conversion and the predictive value of VAI in estimating such unfavorable outcomes...
2017: PloS One
Moritz Augustin, Josef Ladenbauer, Fabian Baumann, Klaus Obermayer
The spiking activity of single neurons can be well described by a nonlinear integrate-and-fire model that includes somatic adaptation. When exposed to fluctuating inputs sparsely coupled populations of these model neurons exhibit stochastic collective dynamics that can be effectively characterized using the Fokker-Planck equation. This approach, however, leads to a model with an infinite-dimensional state space and non-standard boundary conditions. Here we derive from that description four simple models for the spike rate dynamics in terms of low-dimensional ordinary differential equations using two different reduction techniques: one uses the spectral decomposition of the Fokker-Planck operator, the other is based on a cascade of two linear filters and a nonlinearity, which are determined from the Fokker-Planck equation and semi-analytically approximated...
June 23, 2017: PLoS Computational Biology
Andrés E Quiñones, Ido Pen
Explaining the origin of eusociality, with strict division of labour between workers and reproductives, remains one of evolutionary biology's greatest challenges. Specific combinations of genetic, behavioural and demographic traits in Hymenoptera are thought to explain their relatively high frequency of eusociality, but quantitative models integrating such preadaptations are lacking. Here we use mathematical models to show that the joint evolution of helping behaviour and maternal sex ratio adjustment can synergistically trigger both a behavioural change from solitary to eusocial breeding, and a demographic change from a life cycle with two reproductive broods to a life cycle in which an unmated cohort of female workers precedes a final generation of dispersing reproductives...
June 23, 2017: Nature Communications
Marina Duplančić, Vesna Tomašić, Zoran Gomzi
This paper is focused on development of the metal monolithic structure for total oxidation of toluene at low temperature. The well adhered catalyst, based on the mixed oxides of manganese and nickel, is washcoated on the Al/Al2O3 plates as metallic support. The influence of different reaction variables on the catalytic performance in the toluene oxidation is investigated. For the comparison purposes results observed for the manganese-nickel mixed oxide supported on the metallic monolith are compared with those obtained using powder type of the same catalyst...
June 23, 2017: Environmental Technology
Ting Hu, Zhixin Jia, Jinlan Zhang
Acidic glycosphingolipids (AGSLs), which mainly consist of ganglioside and sulfatide moieties, are highly concentrated in the central nervous system. Comprehensive profiling of AGSLs has historically been challenging because of their high complexity and the lack of standards. In this paper, a novel strategy was developed to comprehensively profile AGSLs using ultra-high-performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-Q-TOF-MS). Ganglioside isomers with different glycan chains such as GD1a/ GD1b were completely separated on a C18 column for the first time to our knowledge, facilitated by the addition of formic acid in the mobile phase...
June 23, 2017: Analytical Chemistry
Uran Ferizi, Benoit Scherrer, Torben Schneider, Mohammad Alipoor, Odin Eufracio, Rutger H J Fick, Rachid Deriche, Markus Nilsson, Ana K Loya-Olivas, Mariano Rivera, Dirk H J Poot, Alonso Ramirez-Manzanares, Jose L Marroquin, Ariel Rokem, Christian Pötter, Robert F Dougherty, Ken Sakaie, Claudia Wheeler-Kingshott, Simon K Warfield, Thomas Witzel, Lawrence L Wald, José G Raya, Daniel C Alexander
A large number of mathematical models have been proposed to describe the measured signal in diffusion-weighted (DW) magnetic resonance imaging (MRI). However, model comparison to date focuses only on specific subclasses, e.g. compartment models or signal models, and little or no information is available in the literature on how performance varies among the different types of models. To address this deficiency, we organized the 'White Matter Modeling Challenge' during the International Symposium on Biomedical Imaging (ISBI) 2015 conference...
June 23, 2017: NMR in Biomedicine
F Hübner, C Leithäuser, B Bazrafshan, N Siedow, T J Vogl
The purpose of the study was to develop a simulation approach for laser-induced thermotherapy (LITT) that is based on mathematical models for radiation transport, heat transport, and tissue damage. The LITT ablation was applied to ex vivo pig liver tissue. Experiments were repeated with different laser powers, i.e., 22-34 W, and flow rates of the cooling water in the applicator system, i.e., 47-92 ml/min. During the procedure, the temperature was measured in the liver sample at different distances to the applicator as well as in the cooling circuit using a fiber optic thermometer...
June 22, 2017: Lasers in Medical Science
Yuliya G Alexandrovich, Elena A Kosenko, Elena I Sinauridze, Sergey I Obydennyi, Igor I Kireev, Fazoil I Ataullakhanov, Yuriy G Kaminsky
Erythrocytes (RBCs) loaded with alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALD) can metabolize plasma ethanol and acetaldehyde but with low efficiency. We investigated the rate-limiting factors in ethanol oxidation by these enzymes loaded into RBCs. Mathematical modeling and in vitro experiments on human RBCs loaded simultaneously with ADH and ALD (by hypoosmotic dialysis) were performed. The simulation showed that the rate of nicotinamide-adenine dinucleotide (NAD(+)) generation in RBC glycolysis, but not the activities of the loaded enzymes, is the rate-limiting step in external ethanol oxidation...
2017: BioMed Research International
Milad Shahriari, Ali Bozorgi-Amiri, Shayan Tavakoli, Abolghasem Yousefi-Babadi
Shortening the travel time of patient transfer has clinical implications for many conditions such as cardiac arrest, trauma, stroke and STEMI. As resources are often limited precise calculations are needed. In this paper we consider the location problem for both ground and aerial emergency medical services. Given the uncertainty of when patients are in need of prompt medical attention we consider these demand points to be uncertain. We consider various ways in which ground and helicopter ambulances can work together to make the whole process go faster...
June 15, 2017: American Journal of Emergency Medicine
Peyman Babakhani, Jonathan Bridge, Ruey-An Doong, Tanapon Phenrat
Environmental applications of nanoparticles (NP) increasingly result in widespread NP distribution within porous media where they are subject to various concurrent transport mechanisms including irreversible deposition, attachment/detachment (equilibrium or kinetic), agglomeration, physical straining, site-blocking, ripening, and size exclusion. Fundamental research in NP transport is typically conducted at small scale, and theoretical mechanistic modeling of particle transport in porous media faces challenges when considering the simultaneous effects of transport mechanisms...
June 7, 2017: Advances in Colloid and Interface Science
Torin K Clark, Laurence R Young
BACKGROUND: Increased gravito-inertial acceleration, or hypergravity, such as produced in a centrifuge or in an aircraft coordinated turn, causes humans to systematically overestimate their roll tilt in the dark. This is known as the "G-excess" illusion. We have previously modified a mathematical observer model of dynamic orientation perception to replicate these illusory tilt perceptions. This modified model also made a novel, previously untested, prediction that humans would underestimate acute roll tilt in reduced gravitational environments (hypogravity)...
July 1, 2017: Aerospace Medicine and Human Performance
Gabriela Sehnem Heck, Val Oliveira Pintro, Richard Rene Pereira, Mauricio Boff de Ávila, Nayara Maria Bernhardt Levin, Walter Filgueira de Azevedo
BACKGROUND: Calculation of ligand-binding affinity is an open problem in computational medicinal chemistry. The ability to computationally predict affinities has a beneficial impact in the early stages of drug development, since it allows a mathematical model to assess protein-ligand interactions. Due to the availability of structural and binding information, machine learning methods have been applied to generate scoring functions with good predictive power. OBJECTIVE: Our goal here is to review recent developments in the application of machine learning methods to predict ligand- binding affinity...
June 22, 2017: Current Medicinal Chemistry
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