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Mathematical modelling

Daniel Gartner, Yiye Zhang, Rema Padman
Order sets are a critical component in hospital information systems that are expected to substantially reduce physicians' physical and cognitive workload and improve patient safety. Order sets represent time interval-clustered order items, such as medications prescribed at hospital admission, that are administered to patients during their hospital stay. In this paper, we develop a mathematical programming model and an exact and a heuristic solution procedure with the objective of minimizing physicians' cognitive workload associated with prescribing order sets...
May 27, 2017: Health Care Management Science
Raouf El Cheikh, Samuel Bernard, Nader El Khatib
We present a multiscale mathematical model for the regulation of the cell cycle by the circadian clock. Biologically, the model describes the proliferation of a population of heterogeneous cells connected to each other. The model consists of a high dimensional transport equation structured by molecular contents of the cell cycle-circadian clock coupled oscillator. We propose a computational method for resolution adapted from the concept of particle methods. We study the impact of molecular dynamics on cell proliferation and show an example where discordance of division rhythms between population and single cell levels is observed...
May 24, 2017: Journal of Theoretical Biology
Vincent Bonnet, Vincent Richard, Valentina Camomilla, Gentiane Venture, Aurelio Cappozzo, Raphaël Dumas
To reduce the impact of the soft tissue artefact (STA) on the estimate of skeletal movement using stereophotogrammetric and skin-marker data, multi-body kinematics optimisation (MKO) and extended Kalman filters (EKF) have been proposed. This paper assessed the feasibility and efficiency of these methods when they embed a mathematical model of the STA and simultaneously estimate the ankle, knee and hip joint kinematics and the model parameters. A STA model was used that provides an estimate of the STA affecting the marker-cluster located on a body segment as a function of the kinematics of the adjacent joints...
May 17, 2017: Journal of Biomechanics
P K Tiwari, A K Misra, Ezio Venturino
Synthetic fertilizers and livestock manure are nowadays widely used in agriculture to improve crop yield but nitrogen and phosphorous runoff resulting from their use compromises water quality and contributes to eutrophication phenomena in waterbeds within the countryside and ultimately in the ocean. Alternatively, algae could play an important role in agriculture where they can be used as biofertilizers and soil stabilizers. To examine the possible reuse of the detritus generated by dead algae as fertilizer for crops, we develop three mathematical models building upon each other...
May 27, 2017: Journal of Biological Physics
Naiara Rodriguez-Florez, Jan L Bruse, Alessandro Borghi, Herman Vercruysse, Juling Ong, Greg James, Xavier Pennec, David J Dunaway, N U Owase Jeelani, Silvia Schievano
PURPOSE: Spring-assisted cranioplasty is performed to correct the long and narrow head shape of children with sagittal synostosis. Such corrective surgery involves osteotomies and the placement of spring-like distractors, which gradually expand to widen the skull until removal about 4 months later. Due to its dynamic nature, associations between surgical parameters and post-operative 3D head shape features are difficult to comprehend. The current study aimed at applying population-based statistical shape modelling to gain insight into how the choice of surgical parameters such as craniotomy size and spring positioning affects post-surgical head shape...
May 26, 2017: International Journal of Computer Assisted Radiology and Surgery
Wenwen Wang, Thomas Stiehl, Simon Raffel, Van T Hoang, Isabel Hoffmann, Laura Poisa-Beiro, Borhan R Saeed, Rachel Blume, Linda Manta, Volker Eckstein, Tilmann Bochtler, Patrick Wuchter, Marieke Essers, Anna Jauch, Andreas Trumpp, Anna Marciniak-Czochra, Anthony D Ho, Christoph Lutz
In patients with acute myeloid leukemia and low percentages of aldehyde-dehydrogenase-positive cells, non-leukemic hematopoietic stem cells can be separated from leukemic cells. By relating hematopoietic stem cell frequencies to outcome we detected poor overall- and disease-free survival of patients with low hematopoietic stem cell frequencies. Serial analysis of matched diagnostic and follow-up samples further demonstrated that hematopoietic stem cells increased after chemotherapy in patients that achieved durable remissions...
May 26, 2017: Haematologica
Neil Benson, Piet H van der Graaf, Lambertus A Peletier
A key element of the drug discovery process is target selection. Although the topic is subject to much discussion and experimental effort, there are no defined quantitative rules around optimal selection. Often 'rules of thumb', that have not been subject to rigorous exploration, are used. In this paper we explore the 'rule of thumb' notion that the molecule that initiates a pathway signal is the optimal target. Given the multi-factorial and complex nature of this question, we have simplified an example pathway to its logical minimum of two steps and used a mathematical model of this to explore the different options in the context of typical small and large molecule drugs...
May 23, 2017: European Journal of Pharmaceutical Sciences
Xiaochun Xu, Yu Wang, Jialing Xiang, Jonathan T C Liu, Kenneth M Tichauer
Conventional molecular assessment of tissue through histology, if adapted to fresh thicker samples, has the potential to enhance cancer detection in surgical margins and monitoring of 3D cell culture molecular environments. However, in thicker samples, substantial background staining is common despite repeated rinsing, which can significantly reduce image contrast. Recently, 'paired-agent' methods-which employ co-administration of a control (untargeted) imaging agent-have been applied to thick-sample staining applications to account for background staining...
May 26, 2017: Physics in Medicine and Biology
Mohit Kumar Jolly, Satyendra C Tripathi, Jason A Somarelli, Samir M Hanash, Herbert Levine
Phenotypic plasticity, the ability of cells to reversibly alter their phenotypes in response to signals, presents a significant clinical challenge to treating solid tumors. Tumor cells utilize phenotypic plasticity to evade therapies, metastasize, and colonize distant organs. As a result, phenotypic plasticity can accelerate tumor progression. A well-studied example of phenotypic plasticity is the bidirectional conversions among epithelial, mesenchymal, and hybrid epithelial/mesenchymal phenotype(s). These conversions can alter a repertoire of cellular traits associated with multiple hallmarks of cancer, such as metabolism, immune-evasion, invasion and metastasis...
May 26, 2017: Molecular Oncology
Faryal Khattak, Muhammad Haseeb, Sahar Fazal, A I Bhatti, Mukhtar Ullah
Background: Cervical cancer is the third most common cancer in women throughout the world. The human papillomavirus (HPV) E6 viral protein plays an essential role in proteasomal degradation of the cancer suppressant protein p53. As a result, p53 negative regulation and apoptosis relevant activities are abrogated, facilitating development of cervical cancer. Methods: A mathematical model of E6-p53 interactions was developed using mathematical laws. In-silico simulations were carried out on CellDesigner and as a test case the small molecule drug RITA was considered for its ability to rescue the functions of tumor suppressor p53 by inhibiting E6 mediated proteasomal degradation...
April 1, 2017: Asian Pacific Journal of Cancer Prevention: APJCP
Yan Li
The efficiency evaluation model of integrated energy system, involving many influencing factors, and the attribute values are heterogeneous and non-deterministic, usually cannot give specific numerical or accurate probability distribution characteristics, making the final evaluation result deviation. According to the characteristics of the integrated energy system, a hybrid multi-attribute decision-making model is constructed. The evaluation model considers the decision maker's risk preference. In the evaluation of the efficiency of the integrated energy system, the evaluation value of some evaluation indexes is linguistic value, or the evaluation value of the evaluation experts is not consistent...
May 25, 2017: Environmental Science and Pollution Research International
Martin Pontz, Josef Hofbauer, Reinhard Bürger
Two-locus two-allele models are among the most studied models in population genetics. The reason is that they are the simplest models to explore the role of epistasis for a variety of important evolutionary problems, including the maintenance of polymorphism and the evolution of genetic incompatibilities. Many specific types of models have been explored. However, due to the mathematical complexity arising from the fact that epistasis generates linkage disequilibrium, few general insights have emerged. Here, we study a simpler problem by assuming that linkage disequilibrium can be ignored...
May 25, 2017: Journal of Mathematical Biology
Kuan-Wei Chen, Kang-Ling Liao, Chih-Wen Shih
Somitogenesis is the process for the development of somites in vertebrate embryos. This process is timely regulated by synchronous oscillatory expression of the segmentation clock genes. Mathematical models expressed by delay equations or ODEs have been proposed to depict the kinetics of these genes in interacting cells. Through mathematical analysis, we investigate the parameter regimes for synchronous oscillations and oscillation-arrested in an ODE model and a model with transcriptional and translational delays, both with Michaelis-Menten type degradations...
May 25, 2017: Journal of Mathematical Biology
Klemens Fondi, Piotr A Wozniak, Kinga Howorka, Ahmed M Bata, Gerold C Aschinger, Alina Popa-Cherecheanu, Katarzyna J Witkowska, Anton Hommer, Doreen Schmidl, René M Werkmeister, Gerhard Garhöfer, Leopold Schmetterer
AIMS/HYPOTHESIS: The aim of this study was to compare retinal oxygen extraction in individuals with diabetes with no or mild non-proliferative diabetic retinopathy and healthy age- and sex-matched volunteers. METHODS: A total of 24 participants with type 1 diabetes and 24 healthy age- and sex-matched volunteers were included in this cross-sectional study. Retinal oxygen extraction was measured by combining total retinal blood flow measurements using a custom-built bi-directional Doppler optical coherence tomography system with measurements of oxygen saturation using spectroscopic reflectometry...
May 25, 2017: Diabetologia
José Sérgio Domingues, Marcos de Paula Vale, Carlos Barreira Martinez
The main aim of this study was the formula application of the superficial area of a truncated prolate spheroid (TPS) in Cartesian coordinates in obtaining a cardiac parameter that is not so much discussed in literature, related to the left ventricle (LV) surface area of the human heart, by age and sex. First we obtain a formula for the area of a TPS. Then a simple mathematical model of association of the axes measures of a TPS with the axes of the LV is built. Finally real values of the average dimensions of the humans LV are used to measure surface areas approximations of this heart chamber...
2017: TheScientificWorldJournal
Linpei Jia, Weiguang Zhang, Xiangmei Chen
At present, no single indicator could be used as a golden index to estimate aging process. The biological age (BA), which combines several important biomarkers with mathematical modeling, has been proposed for >50 years as an aging estimation method to replace chronological age (CA). The common methods used for BA estimation include the multiple linear regression (MLR), the principal component analysis (PCA), the Hochschild's method, and the Klemera and Doubal's method (KDM). The fundamental differences in these four methods are the roles of CA and the selection criteria of aging biomarkers...
2017: Clinical Interventions in Aging
E Mossotto, J J Ashton, T Coelho, R M Beattie, B D MacArthur, S Ennis
Paediatric inflammatory bowel disease (PIBD), comprising Crohn's disease (CD), ulcerative colitis (UC) and inflammatory bowel disease unclassified (IBDU) is a complex and multifactorial condition with increasing incidence. An accurate diagnosis of PIBD is necessary for a prompt and effective treatment. This study utilises machine learning (ML) to classify disease using endoscopic and histological data for 287 children diagnosed with PIBD. Data were used to develop, train, test and validate a ML model to classify disease subtype...
May 25, 2017: Scientific Reports
Niranchan Paskaranandavadivel, Leo K Cheng, Peng Du, Jack M Rogers, Gregory O'Grady
Slow waves play a central role in coordinating gastric motor activity. High-resolution mapping of extracellular potentials from the stomach provides spatiotemporal detail on normal and dysrhythmic slow-wave patterns. All mapping studies to date have focused exclusively on tissue activation; however, the recovery phase contains vital information on repolarization heterogeneity, the excitable gap, and refractory tail interactions, but has not been investigated. Here, we report a method to identify the recovery phase in slow-wave mapping data...
May 25, 2017: American Journal of Physiology. Gastrointestinal and Liver Physiology
Manuel Dorado-Moreno, María Pérez-Ortiz, Pedro A Gutiérrez, Rubén Ciria, Javier Briceño, César Hervás-Martínez
OBJECTIVE: Create an efficient decision-support model to assist medical experts in the process of organ allocation in liver transplantation. The mathematical model proposed here uses different sources of information to predict the probability of organ survival at different thresholds for each donor-recipient pair considered. Currently, this decision is mainly based on the Model for End-stage Liver Disease, which depends only on the severity of the recipient and obviates donor-recipient compatibility...
March 2017: Artificial Intelligence in Medicine
Sora Yoon, Dougu Nam
BACKGROUND: In differential expression analysis of RNA-sequencing (RNA-seq) read count data for two sample groups, it is known that highly expressed genes (or longer genes) are more likely to be differentially expressed which is called read count bias (or gene length bias). This bias had great effect on the downstream Gene Ontology over-representation analysis. However, such a bias has not been systematically analyzed for different replicate types of RNA-seq data. RESULTS: We show that the dispersion coefficient of a gene in the negative binomial modeling of read counts is the critical determinant of the read count bias (and gene length bias) by mathematical inference and tests for a number of simulated and real RNA-seq datasets...
May 25, 2017: BMC Genomics
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