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https://www.readbyqxmd.com/read/27936449/methotrexate-treated-ectopic-pregnancy-beta-human-chorionic-gonadotropin-serum-changes-as-a-success-predictor-using-a-mathematical-model-validation
#1
Aleksandra Kovaleva, Natalia Irishina, Augusto Pereira, Tatiana Cuesta-Guardiola, Luis Ortiz-Quintana
BACKGROUND: Surgical rescue of methotrexate-treated ectopic pregnancy is necessary when tubal rupture or medical therapy failure is detected during post-therapeutic monitoring. It is known that an increased beta human chorionic gonadotropin (β-hCG) concentration is the most important factor associated with treatment failure. Therefore, we suggested that relative changes in serum β-hCG could predict a successful result of medical treatment, leading to facilitation of the decision to forgo the prospect of possible surgical rescue...
October 27, 2016: European Journal of Obstetrics, Gynecology, and Reproductive Biology
https://www.readbyqxmd.com/read/27936217/quantum-decision-theory-in-simple-risky-choices
#2
Maroussia Favre, Amrei Wittwer, Hans Rudolf Heinimann, Vyacheslav I Yukalov, Didier Sornette
Quantum decision theory (QDT) is a recently developed theory of decision making based on the mathematics of Hilbert spaces, a framework known in physics for its application to quantum mechanics. This framework formalizes the concept of uncertainty and other effects that are particularly manifest in cognitive processes, which makes it well suited for the study of decision making. QDT describes a decision maker's choice as a stochastic event occurring with a probability that is the sum of an objective utility factor and a subjective attraction factor...
2016: PloS One
https://www.readbyqxmd.com/read/27936138/diffusion-based-design-of-multi-layered-ophthalmic-lenses-for-controlled-drug-release
#3
Andreia F R Pimenta, Ana Paula Serro, Patrizia Paradiso, Benilde Saramago, Rogério Colaço
The study of ocular drug delivery systems has been one of the most covered topics in drug delivery research. One potential drug carrier solution is the use of materials that are already commercially available in ophthalmic lenses for the correction of refractive errors. In this study, we present a diffusion-based mathematical model in which the parameters can be adjusted based on experimental results obtained under controlled conditions. The model allows for the design of multi-layered therapeutic ophthalmic lenses for controlled drug delivery...
2016: PloS One
https://www.readbyqxmd.com/read/27936103/washback-effect-of-university-entrance-exams-in-applied-mathematics-to-social-sciences
#4
Luis J Rodríguez-Muñiz, Patricia Díaz, Verónica Mier, Pedro Alonso
Curricular issues of subject Applied Mathematics to Social Sciences are studied in relation to university entrance exams performed in several Spanish regions between 2009-2014. By using quantitative and qualitative analyses, it has been studied how these exams align with curriculum and how they produce a washback on curriculum and teachers' work. Additionally, one questionnaire about teachers' practices has been performed, in order to find out how the exams are influencing teaching methodology development. Main results obtained show that evaluation is producing a bias on the official curriculum, substantially simplifying the specific orientation that should guide applied mathematics...
2016: PloS One
https://www.readbyqxmd.com/read/27936091/development-of-serum-marker-models-to-increase-diagnostic-accuracy-of-advanced-fibrosis-in-nonalcoholic-fatty-liver-disease-the-new-linki-algorithm-compared-with-established-algorithms
#5
Byron Lykiardopoulos, Hannes Hagström, Mats Fredrikson, Simone Ignatova, Per Stål, Rolf Hultcrantz, Mattias Ekstedt, Stergios Kechagias
BACKGROUND AND AIM: Detection of advanced fibrosis (F3-F4) in nonalcoholic fatty liver disease (NAFLD) is important for ascertaining prognosis. Serum markers have been proposed as alternatives to biopsy. We attempted to develop a novel algorithm for detection of advanced fibrosis based on a more efficient combination of serological markers and to compare this with established algorithms. METHODS: We included 158 patients with biopsy-proven NAFLD. Of these, 38 had advanced fibrosis...
2016: PloS One
https://www.readbyqxmd.com/read/27935963/modeling-and-simulating-passenger-behavior-for-a-station-closure-in-a-rail-transit-network
#6
Haodong Yin, Baoming Han, Dewei Li, Jianjun Wu, Huijun Sun
A station closure is an abnormal operational situation in which the entrances or exits of a rail transit station have to be closed for some time due to an unexpected incident. A novel approach is developed to estimate the impacts of the alternative station closure scenarios on both passenger behavioral choices at the individual level and passenger demand at the disaggregate level in a rail transit network. Therefore, the contributions of this study are two-fold: (1) A basic passenger behavior optimization model is mathematically constructed based on 0-1 integer programming to describe passengers' responses to alternative origin station closure scenarios and destination station closure scenarios; this model also considers the availability of multi-mode transportation and the uncertain duration of the station closure; (2) An integrated solution algorithm based on the passenger simulation is developed to solve the proposed model and to estimate the effects of a station closure on passenger demand in a rail transit network...
2016: PloS One
https://www.readbyqxmd.com/read/27935947/a-stochastic-model-of-the-yeast-cell-cycle-reveals-roles-for-feedback-regulation-in-limiting-cellular-variability
#7
Debashis Barik, David A Ball, Jean Peccoud, John J Tyson
The cell division cycle of eukaryotes is governed by a complex network of cyclin-dependent protein kinases (CDKs) and auxiliary proteins that govern CDK activities. The control system must function reliably in the context of molecular noise that is inevitable in tiny yeast cells, because mistakes in sequencing cell cycle events are detrimental or fatal to the cell or its progeny. To assess the effects of noise on cell cycle progression requires not only extensive, quantitative, experimental measurements of cellular heterogeneity but also comprehensive, accurate, mathematical models of stochastic fluctuations in the CDK control system...
December 2016: PLoS Computational Biology
https://www.readbyqxmd.com/read/27935934/beyond-the-hypercube-evolutionary-accessibility-of-fitness-landscapes-with-realistic-mutational-networks
#8
Marcin Zagorski, Zdzislaw Burda, Bartlomiej Waclaw
Evolutionary pathways describe trajectories of biological evolution in the space of different variants of organisms (genotypes). The probability of existence and the number of evolutionary pathways that lead from a given genotype to a better-adapted genotype are important measures of accessibility of local fitness optima and the reproducibility of evolution. Both quantities have been studied in simple mathematical models where genotypes are represented as binary sequences of two types of basic units, and the network of permitted mutations between the genotypes is a hypercube graph...
December 2016: PLoS Computational Biology
https://www.readbyqxmd.com/read/27935654/research-of-bionic-design-on-tools-with-rostrum-of-cyrtotrachelus-bugueti-guer-coleoptera-curculionidae
#9
Shun Xu, Longhai Li, Jin Tong, Mo Li
To improve the torsional resistance capability of multilayered composite pipes, a bionic design was presented based on the rostrum of Cyrtotrachelus Bugueti Guer. Morphology and mechanical properties of the weevil's rostrum were studied. Scanning electron microscope (SEM) was employed to observe the macro-/microstructure and inner structure. Nanoindentation was carried out to measure the elastic modulus and the hardness of the biological materials. Based on the structure of rostrum, a mathematical model of multilayered biomimetic pipe was established with the statistical methods...
December 9, 2016: Microscopy Research and Technique
https://www.readbyqxmd.com/read/27935313/on-the-energy-ordering-of-molecular-orbitals
#10
Peter Puschnig, A Daniel Boese, Martin Willenbockel, Marcel Meyer, Daniel Lüftner, Eva Maria Reinisch, Thomas Ules, Georg Koller, Serguei Soubatch, Michael G Ramsey, Frank Stefan Tautz
Orbitals are invaluable in providing a model of bonding in molecules or between molecules and surfaces. Most present-day methods in computational chemistry begin by calculating the molecular orbitals of the system. To what extent have these mathematical objects analogues in the real world? To shed light on this intriguing question, we employ a photoemission tomography study on monolayers of 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) grown on three Ag surfaces. The characteristic photoelectron angular distribution enables us to assign individual molecular orbitals to the emission features...
December 9, 2016: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/27934610/in-vivo-validation-of-mathematically-derived-fractional-flow-reserve-for-assessing-haemodynamics-of-coronary-tandem-lesions
#11
Jihoon Kweon, Young-Hak Kim, Dong Hyun Yang, June-Goo Lee, Jae-Hyung Roh, Gary S Mintz, Seung-Whan Lee, Seong-Wook Park
AIMS: Our aim was to propose a prediction model for the post-stenting fractional flow reserve (FFR'd,pred) at a position distal to the tandem lesion. METHODS AND RESULTS: Using the FFR at a position proximal to the tandem lesion (FFRp), and the FFR gradients across proximal (ΔFFRp) and distal (ΔFFRd) stenoses, FFR'd,pred after treating either the distal or proximal lesion was predicted as FFRp-ΔFFRp/(1-1.33kΔFFRd) or FFRp-ΔFFRd/(1-1.33ΔFFRp), respectively...
December 10, 2016: EuroIntervention
https://www.readbyqxmd.com/read/27933657/analysis-of-temozolomide-resistance-in-low-grade-gliomas-by-using-a-mechanistic-mathematical-model
#12
Edouard Ollier, Pauline Mazzocco, Damien Ricard, Gentian Kaloshi, Ahmed Idbaih, Agusti Alentorn, Dimitri Psimaras, Jérôme Honnorat, Jean-Yves Delattre, Emmanuel Grenier, François Ducray, Adeline Samson
Understanding how tumours develop resistance to chemotherapy is a major issue in oncology. When treated with temozolomide (TMZ), an oral alkylating chemotherapy drug, most low-grade gliomas (LGG) show an initial volume decrease but this effect is rarely long lasting. In addition, it has been suggested that TMZ may drive tumour progression in a subset of patients as a result of acquired resistance. Using longitudinal tumour size measurements from 121 patients, the aim of the present study was to develop a semi-mechanistic mathematical model to determine whether resistance of LGG to TMZ was more likely to result from primary and/or from chemotherapy-induced acquired resistance that may contribute to tumour progression...
December 9, 2016: Fundamental & Clinical Pharmacology
https://www.readbyqxmd.com/read/27933417/on-the-characterization-of-the-heterogeneous-mechanical-response-of-human-brain-tissue
#13
Antonio E Forte, Stephen M Gentleman, Daniele Dini
The mechanical characterization of brain tissue is a complex task that scientists have tried to accomplish for over 50 years. The results in the literature often differ by orders of magnitude because of the lack of a standard testing protocol. Different testing conditions (including humidity, temperature, strain rate), the methodology adopted, and the variety of the species analysed are all potential sources of discrepancies in the measurements. In this work, we present a rigorous experimental investigation on the mechanical properties of human brain, covering both grey and white matter...
December 8, 2016: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/27933241/numerical-solution-of-linear-and-nonlinear-fredholm-integral-equations-by-using-weighted-mean-value-theorem
#14
Ahmet Altürk
Mean value theorems for both derivatives and integrals are very useful tools in mathematics. They can be used to obtain very important inequalities and to prove basic theorems of mathematical analysis. In this article, a semi-analytical method that is based on weighted mean-value theorem for obtaining solutions for a wide class of Fredholm integral equations of the second kind is introduced. Illustrative examples are provided to show the significant advantage of the proposed method over some existing techniques...
2016: SpringerPlus
https://www.readbyqxmd.com/read/27933073/mistletoe-berry-outline-mapping-with-a-path-curve-function-and-recording-the-circadian-rhythm-of-their-phenotypic-shape-change
#15
Renatus Derbidge, Stephan Baumgartner, Peter Heusser
This paper presents a discovery: the change of the outline shape of mistletoe (Viscum album ssp. album) berries in vivo and in situ during ripening. It was found that a plant organ that is usually considered to merely increase in size actually changes shape in a specific rhythmic fashion. We introduce a new approach to chronobiological research on a macro-phenotypic scale to trace changes over long periods of time (with a resolution from hours to months) by using a dynamic form-determining parameter called Lambda (λ)...
2016: Frontiers in Plant Science
https://www.readbyqxmd.com/read/27933039/the-contribution-of-mathematical-modeling-to-understanding-dynamic-aspects-of-rumen-metabolism
#16
André Bannink, Henk J van Lingen, Jennifer L Ellis, James France, Jan Dijkstra
All mechanistic rumen models cover the main drivers of variation in rumen function, which are feed intake, the differences between feedstuffs and feeds in their intrinsic rumen degradation characteristics, and fractional outflow rate of fluid and particulate matter. Dynamic modeling approaches are best suited to the prediction of more nuanced responses in rumen metabolism, and represent the dynamics of the interactions between substrates and micro-organisms and inter-microbial interactions. The concepts of dynamics are discussed for the case of rumen starch digestion as influenced by starch intake rate and frequency of feed intake, and for the case of fermentation of fiber in the large intestine...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27933004/policy-implications-of-achievement-testing-using-multilevel-models-the-case-of-brazilian-elementary-schools
#17
Igor G Menezes, Victor R Duran, Euclides J Mendonça Filho, Tainã J Veloso, Stella M S Sarmento, Christine L Paget, Kai Ruggeri
Large-scale educational assessment has been established as source of descriptive, evaluative and interpretative information that influence educational policies worldwide throughout the last third of the twentieth century. In the 1990s the Brazilian Ministry of Education developed the National Basic Education Assessment System (SAEB) that regularly measures management, resource and contextual school features and academic achievement in public and private institutions. In 2005, after significant piloting and review of the SAEB, a new sampling strategy was taken and Prova Brasil became the new instrument used by the Ministry to assess skills in Portuguese (reading comprehension) and Mathematics (problem solving), as well as collecting contextual information concerning the school, principal, teacher, and the students...
2016: Frontiers in Psychology
https://www.readbyqxmd.com/read/27932987/limits-of-applicability-of-the-voronoi-tessellation-determined-by-centers-of-cell-nuclei-to-epithelium-morphology
#18
Sara Kaliman, Christina Jayachandran, Florian Rehfeldt, Ana-Sunčana Smith
It is well accepted that cells in the tissue can be regarded as tiles tessellating space. A number of approaches were developed to find an appropriate mathematical description of such cell tiling. A particularly useful approach is the so called Voronoi tessellation, built from centers of mass of the cell nuclei (CMVT), which is commonly used for estimating the morphology of cells in epithelial tissues. However, a study providing a statistically sound analysis of this method's accuracy is not available in the literature...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27932970/bayesian-inference-of-synaptic-quantal-parameters-from-correlated-vesicle-release
#19
Alex D Bird, Mark J Wall, Magnus J E Richardson
Synaptic transmission is both history-dependent and stochastic, resulting in varying responses to presentations of the same presynaptic stimulus. This complicates attempts to infer synaptic parameters and has led to the proposal of a number of different strategies for their quantification. Recently Bayesian approaches have been applied to make more efficient use of the data collected in paired intracellular recordings. Methods have been developed that either provide a complete model of the distribution of amplitudes for isolated responses or approximate the amplitude distributions of a train of post-synaptic potentials, with correct short-term synaptic dynamics but neglecting correlations...
2016: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/27932907/optimized-r-functions-for-analysis-of-ecological-community-data-using-the-r-virtual-laboratory-rvlab
#20
Constantinos Varsos, Theodore Patkos, Anastasis Oulas, Christina Pavloudi, Alexandros Gougousis, Umer Zeeshan Ijaz, Irene Filiopoulou, Nikolaos Pattakos, Edward Vanden Berghe, Antonio Fernández-Guerra, Sarah Faulwetter, Eva Chatzinikolaou, Evangelos Pafilis, Chryssoula Bekiari, Martin Doerr, Christos Arvanitidis
BACKGROUND: Parallel data manipulation using R has previously been addressed by members of the R community, however most of these studies produce ad hoc solutions that are not readily available to the average R user. Our targeted users, ranging from the expert ecologist/microbiologists to computational biologists, often experience difficulties in finding optimal ways to exploit the full capacity of their computational resources. In addition, improving performance of commonly used R scripts becomes increasingly difficult especially with large datasets...
2016: Biodiversity Data Journal
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