keyword
MENU ▼
Read by QxMD icon Read
search

Mathematical model

keyword
https://www.readbyqxmd.com/read/28538814/maize-dry-matter-production-and-macronutrient-extraction-model-as-a-new-approach-for-fertilizer-rate-estimation
#1
Karla V Martins, Durval Dourado-Neto, Klaus Reichardt, José L Favarin, Felipe F Sartori, Guilherme Felisberto, Simone C Mello
Decision support for nutrient application remains an enigma if based on soil nutrient analysis. If the crop could be used as an auxiliary indicator, the plant nutrient status during different growth stages could complement the soil test, improving the fertilizer recommendation. Nutrient absorption and partitioning in the plant are here studied and described with mathematical models. The objective of this study considers the temporal variation of the nutrient uptake rate, which should define crop needs as compared to the critical content in soil solution...
May 22, 2017: Anais da Academia Brasileira de Ciências
https://www.readbyqxmd.com/read/28538153/new-continuum-approaches-for-determining-protein-induced-membrane-deformations
#2
David Argudo, Neville P Bethel, Frank V Marcoline, Charles W Wolgemuth, Michael Grabe
The influence of the membrane on transmembrane proteins is central to a number of biological phenomena, notably the gating of stretch activated ion channels. Conversely, membrane proteins can influence the bilayer, leading to the stabilization of particular membrane shapes, topological changes that occur during vesicle fission and fusion, and shape-dependent protein aggregation. Continuum elastic models of the membrane have been widely used to study protein-membrane interactions. These mathematical approaches produce physically interpretable membrane shapes, energy estimates for the cost of deformation, and a snapshot of the equilibrium configuration...
May 23, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28535530/mathematical-model-of-potassium-profiling-in-chronic-dialysis
#3
Mauro Ursino, Gabriele Donati
Potassium balance is a difficult task in hemodialysis: low potassium in the dialysate is associated with a high risk of sudden cardiac death, whereas excessive dialysate potassium may provoke insufficient removal and hyperkalemia. A better understanding of the problem can be achieved with the use of mathematical models of solute kinetics. This study is aimed at presenting an improved model of solute kinetics and fluid shifts during hemodialysis. It comprises a 2-compartment (intracellular and extracellular) description of sodium, potassium, and urea, including volume fluid shifts induced by osmotic forces...
2017: Contributions to Nephrology
https://www.readbyqxmd.com/read/28535441/enantioselective-metabolism-of-triadimefon-and-its-chiral-metabolite-triadimenol-in-lizards
#4
Qiuxuan Shen, Jitong Li, Peng Xu, Wei Li, Guoqiang Zhuang, Yinghuan Wang
Chinese lizards (Eremias argus) were exposed to separated R-(-)-triadimefon, S-(+)-triadimefon and racemic triadimefon to evaluate enantioselective accumulation of triadimefon. After single oral administration of R-(-)-triadimefon, S-(+)-triadimefon and racemic triadimefon, the time-concentration curves in different tissues were found to be different. Triadimefon enantiomers crossed the blood-brain barrier and brain is a main target organ. The residues of triadimefon enantiomers in fat were highest after 24h indicating that fat was the main tissue of accumulation...
May 20, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28535127/modelling-virus-coinfection-to-inform-management-of-maize-lethal-necrosis-in-kenya
#5
Frank Hilker, Linda Allen, Vrushali Bokil, Cheryl Briggs, Zhilan Feng, Karen A Garrett, Louis Gross, Frédéric Hamelin, Michael J Jeger, Carrie Manore, Alison Power, Margaret Redinbaugh, Megan Rúa, Nik J Cunniffe
Maize lethal necrosis (MLN) has emerged as a serious threat to food security in sub-Saharan Africa. MLN is caused by coinfection with two viruses, maize chlorotic mottle virus (MCMV) and a potyvirus, often sugarcane mosaic virus (SCMV). To better understand dynamics of MLN and to provide insight into disease management, we model the spread of the viruses causing MLN within and between growing seasons. The model allows for transmission via vectors, soil and seeds, as well as exogenous sources of infection. Following model parameterisation, we predict how management affects disease prevalence and crop performance over multiple seasons...
May 23, 2017: Phytopathology
https://www.readbyqxmd.com/read/28534885/modeling-combination-hcv-prevention-among-hiv-infected-men-who-have-sex-with-men-and-people-who-inject-drugs
#6
Natasha K Martin, Britt Skaathun, Peter Vickerman, David Stuart
People who inject drugs (PWID) and HIV-infected men who have sex with men (MSM) are key risk groups for HCV transmission. Mathematical modeling studies can help elucidate what level and combination of prevention intervention scale-up is required to control or eliminate epidemics among these key populations. We discuss the evidence surrounding HCV prevention interventions and provide an overview of the mathematical modeling literature projecting the impact of scaled-up HCV prevention among PWID and HIV-infected MSM...
May 23, 2017: AIDS Reviews
https://www.readbyqxmd.com/read/28534878/successive-range-expansion-promotes-diversity-and-accelerates-evolution-in-spatially-structured-microbial-populations
#7
Felix Goldschmidt, Roland R Regoes, David R Johnson
Successive range expansions occur within all domains of life, where one population expands first (primary expansion) and one or more secondary populations then follow (secondary expansion). In general, genetic drift reduces diversity during range expansion. However, it is not clear whether the same effect applies during successive range expansion, mainly because the secondary population must expand into space occupied by the primary population. Here we used an experimental microbial model system to show that, in contrast to primary range expansion, successive range expansion promotes local population diversity...
May 23, 2017: ISME Journal
https://www.readbyqxmd.com/read/28534854/methodical-challenges-and-a-possible-resolution-in-the-assessment-of-receptor-reserve-for-adenosine-an-agonist-with-short-half-life
#8
Judit Zsuga, Tamas Erdei, Katalin Szabó, Nora Lampe, Csaba Papp, Akos Pinter, Andras Jozsef Szentmiklosi, Bela Juhasz, Zoltán Szilvássy, Rudolf Gesztelyi
The term receptor reserve, first introduced and used in the traditional receptor theory, is an integrative measure of response-inducing ability of the interaction between an agonist and a receptor system (consisting of a receptor and its downstream signaling). The underlying phenomenon, i.e., stimulation of a submaximal fraction of receptors can apparently elicit the maximal effect (in certain cases), provides an opportunity to assess the receptor reserve. However, determining receptor reserve is challenging for agonists with short half-lives, such as adenosine...
May 19, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28534805/a-novel-approach-to-implement-takagi-sugeno-fuzzy-models
#9
Chia-Wen Chang, Chin-Wang Tao
This paper proposes new algorithms based on the fuzzy c-regressing model algorithm for Takagi-Sugeno (T-S) fuzzy modeling of the complex nonlinear systems. A fuzzy c-regression state model (FCRSM) algorithm is a T-S fuzzy model in which the functional antecedent and the state-space-model-type consequent are considered with the available input-output data. The antecedent and consequent forms of the proposed FCRSM consists mainly of two advantages: one is that the FCRSM has low computation load due to only one input variable is considered in the antecedent part; another is that the unknown system can be modeled to not only the polynomial form but also the state-space form...
May 16, 2017: IEEE Transactions on Cybernetics
https://www.readbyqxmd.com/read/28534055/experimental-determination-of-surface-heat-transfer-coefficient-in-a-dry-ice-ethanol-cooling-bath-using-a-numerical-approach
#10
M V Santos, M Sansinena, N Zaritzky, J Chirife
  BACKGROUND: Dry ice-ethanol bath (-78 degree C) have been widely used in low temperature biological research to attain rapid cooling of samples below freezing temperature. The prediction of cooling rates of biological samples immersed in dry ice-ethanol bath is of practical interest in cryopreservation. The cooling rate can be obtained using mathematical models representing the heat conduction equation in transient state. Additionally, at the solid cryogenic-fluid interface, the knowledge of the surface heat transfer coefficient (h) is necessary for the convective boundary condition in order to correctly establish the mathematical problem...
March 2017: Cryo Letters
https://www.readbyqxmd.com/read/28533970/a-comparison-of-freezing-damage-during-isochoric-and-isobaric-freezing-of-the-potato
#11
Chenang Lyu, Gabriel Nastase, Gideon Ukpai, Alexandru Serban, Boris Rubinsky
BACKGROUND: Freezing is commonly used for food preservation. It is usually done under constant atmospheric pressure (isobaric). While extending the life of the produce, isobaric freezing has detrimental effects. It causes loss of food weight and changes in food quality. Using thermodynamic analysis, we have developed a theoretical model of the process of freezing in a constant volume system (isochoric). The mathematical model suggests that the detrimental effects associated with isobaric freezing may be reduced in an isochoric freezing system...
2017: PeerJ
https://www.readbyqxmd.com/read/28533478/real-time-near-infrared-raman-spectroscopy-for-the-diagnosis-of-nasopharyngeal-cancer
#12
Lim Chwee Ming, Nagaraja Rao Gangodu, Thomas Loh, Wei Zheng, Jianfeng Wang, Kan Lin, Huang Zhiwei
Near-infrared (NIR) Raman spectroscopy has been investigated as a tool to differentiate nasopharyngeal cancer (NPC) from normal nasopharyngeal tissue in an ex-vivo setting. Recently, we have miniaturized the fiber-optic Raman probe to investigate its utility in real time in-vivo surveillance of NPC patients. A posterior probability model using partial linear square (PLS) mathematical technique was constructed to verify the sensitivity and specificity of Raman spectroscopy in diagnosing NPC from post-irradiated and normal tissue using a diagnostic algorithm from three significant latent variables...
May 8, 2017: Oncotarget
https://www.readbyqxmd.com/read/28533405/spatial-evolutionary-games-with-weak-selection
#13
Mridu Nanda, Richard Durrett
Recently, a rigorous mathematical theory has been developed for spatial games with weak selection, i.e., when the payoff differences between strategies are small. The key to the analysis is that when space and time are suitably rescaled, the spatial model converges to the solution of a partial differential equation (PDE). This approach can be used to analyze all [Formula: see text] games, but there are a number of [Formula: see text] games for which the behavior of the limiting PDE is not known. In this paper, we give rules for determining the behavior of a large class of [Formula: see text] games and check their validity using simulation...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28533216/a-diverse-community-to-study-communities-integration-of-experiments-and-mathematical-models-to-study-microbial-consortia
#14
Antonella Succurro, Fiona Wanjiku Moejes, Oliver Ebenhöh
The last few years have seen the advancement of high-throughput experimental techniques produce an extraordinary amount of data. Bioinformatics and statistical analyses have become instrumental to interpreting the information coming from e.g. sequencing data, and often motivate further targeted experiments. The broad discipline of "computational biology" spans far beyond the well-established field of bioinformatics, but it is our impression that more theoretical methods like mathematical models are not yet as well integrated in the research studying microbial interactions...
May 22, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28533120/evaluation-of-new-chemical-entities-as-substrates-of-liver-transporters-in-the-pharmaceutical-industry-response-to-regulatory-requirements-and-future-steps
#15
Noriko Okudaira
This article discusses the evaluation of drug candidates as hepatic transporter substrates. Recently, research on the applications of hepatic transporters in the pharmaceutical industry has improved to meet the requirements of the regulatory guidelines for the evaluation of drug interactions. To identify the risk of transporter-mediated drug-drug interactions (DDIs) at an early stage of drug development, we employed a strategy of reviewing the in vivo animal pharmacokinetics and tissue distribution data obtained in the discovery stage together with the in vitro data obtained for regulatory submission...
May 19, 2017: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28532591/modeling-stability-analysis-and-computational-aspects-of-some-simplest-nonlinear-fuzzy-two-term-controllers-derived-via-center-of-area-gravity-defuzzification
#16
N K Arun, B M Mohan
The mathematical models reported in the literature so far have been found using Center of Sums (CoS) defuzzification method only. It appears that no one has found models using Center of Area (CoA) or Center of Gravity (CoG) defuzzification method. Although there have been some works reported to deal with modeling of fuzzy controllers via Centroid method, all of them have in fact used CoS method only. In this paper, for the first time mathematical models of the simplest Mamdani type fuzzy Proportional Integral (PI)/Proportional Derivative (PD) controllers via CoG defuzzification are presented...
May 19, 2017: ISA Transactions
https://www.readbyqxmd.com/read/28532263/establishment-and-assessment-of-a-novel-in-vitro-bio-pk-pd-system-in-predicting-the-in-vivo-pharmacokinetics-and-pharmacodynamics-of-cyclophosphamide
#17
Shanshan Tong, Hong Sun, Caifu Xue, Hanmei Chen, Jing Liu, Huiying Yang, Ning Zhou, Xiaoqiang Xiang, Weimin Cai
1. A novel bio-pharmacokinetic/pharmacodynamic (PK/PD) system was established and assessed in predicting the PK parameters and PD effects of the model drug cyclophosphamide (CP) considering the interrelationships between drug metabolism, pharmacological effects and dynamic blood circulation processes in vitro. 2. The system contains a peristaltic pump, a reaction chamber with rat liver microsomes (RLMs) encapsulated in pluronic F127-acrylamide-bisacrylamide (FAB) hydrogels, an effector cell chamber and a recirculating pipeline...
May 23, 2017: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
https://www.readbyqxmd.com/read/28531864/determination-of-volumetric-gas-liquid-mass-transfer-coefficient-of-carbon-monoxide-in-a-batch-cultivation-system-using-kinetic-simulations
#18
Nulee Jang, Muhammad Yasin, Shinyoung Park, Robert W Lovitt, In Seop Chang
A mathematical model of microbial kinetics was introduced to predict the overall volumetric gas-liquid mass transfer coefficient (kLa) of carbon monoxide (CO) in a batch cultivation system. The cell concentration (X), acetate concentration (Cace), headspace gas (Nco and [Formula: see text] ), dissolved CO concentration in the fermentation medium (Cco), and mass transfer rate (R) were simulated using a variety of kLa values. The simulated results showed excellent agreement with the experimental data for a kLa of 13/hr...
May 6, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28531861/greenhouse-gases-from-membrane-bioreactors-mathematical-modelling-sensitivity-and-uncertainty-analysis
#19
Giorgio Mannina, Alida Cosenza, George A Ekama
In this study a new mathematical model to quantify greenhouse gas emissions (namely, carbon dioxide and nitrous oxide) from membrane bioreactors (MBRs) is presented. The model has been adopted to predict the key processes of a pilot plant with pre-denitrification MBR scheme, filled with domestic and saline wastewater. The model was calibrated by adopting an advanced protocol based on an extensive dataset. In terms of nitrous oxide, the results show that an important role is played by the half saturation coefficients related to nitrogen removal processes and the model factors affecting the oxygen transfer rate in the aerobic and MBR tanks...
May 6, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28531261/age-of-acquiring-causal-human-papillomavirus-hpv-infections-leveraging-simulation-models-to-explore-the-natural-history-of-hpv-induced-cervical-cancer
#20
Emily A Burger, Jane J Kim, Stephen Sy, Philip E Castle
Background.: Although new human papillomavirus (HPV) infections can occur at all ages, the age at which women acquire their "causal" HPV infection that develops into cervical cancer is poorly understood and practically unobservable. We aimed to estimate the age distribution at which individuals acquired their causal HPV infection in the absence of HPV vaccination or screening to help guide the optimal use of both. Methods.: Using an empirically calibrated mathematical model that simulates the natural history of cervical cancer, we estimated the cumulative number of causal HPV infections by age, stratified by HPV genotype (HPV16 vs...
May 20, 2017: Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America
keyword
keyword
179
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"