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Modeling and Simulation

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https://www.readbyqxmd.com/read/29783121/the-influence-of-nail-blocking-conditions-in-cattle-femoral-fractures
#1
Leopoldo A Paolucci, Estevam B Las Casas, Rafael R Faleiros, Cahuê F R Paz, Sergio S Rocha Junior
BACKGROUND: To investigate the effect of different fixation strategies of the intramedullary interlocking nail (IIN) on the mechanical behavior of a polymeric implant applied for femoral fracture fixation in calves, and to evaluate the performance of a glass fiber-reinforced polymer applied in a bovine femoral fracture reduction system, five Holstein male animals with a mean weight (±SD) of 62.8 ± 20.4 kg and aged 74 ± 15 were used to generate biomechanical parameters for this study...
May 7, 2018: Research in Veterinary Science
https://www.readbyqxmd.com/read/29783115/long-term-trends-in-no-2-columns-related-to-economic-developments-and-air-quality-policies-from-1997-to-2016-in-china
#2
Xiuying Zhang, Wuting Zhang, Xuehe Lu, Xuejun Liu, Dongmei Chen, Lei Liu, Xianjin Huang
This study detected the long-term trends in NO2 concentrations in China from 1997 to 2016 based on the NO2 columns from GOME, SCIAMACHY, and GOME-2A. Both differences in the time-overlapped NO2 columns from GOME vs. SCIAMACHAY and SCIAMACHAY vs. GOME-2A showed seasonal variations, and the annual NO2 columns from GOME were 0.9% higher than those from SCIAMACHY, which exceeded that from GOME-2A by 14%. The long-term trends of the NO2 columns on a provincial scale could be simulated by cubic models (0.60 < R2  < 0...
May 18, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29783113/automated-uhplc-separation-of-10-pharmaceutical-compounds-using-software-modeling
#3
A Zöldhegyi, H-J Rieger, I Molnár, L Fekhretdinova
Human mistakes are still one of the main reasons of underlying regulatory affairs that in a compliance with FDA's Data Integrity and Analytical Quality by Design (AQbD) must be eliminated. To develop smooth, fast and robust methods that are free of human failures, a state-of-the-art automation was presented. For the scope of this study, a commercial software (DryLab) and a model mixture of 10 drugs were subjected to testing. Following AQbD-principles, the best available working point was selected and conformational experimental runs, i...
March 20, 2018: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29782960/the-acute-and-residual-effects-of-escalating-analgesic-range-doses-of-ketamine-on-driving-performance-a-simulator-study
#4
Amie C Hayley, Maja Green, Luke A Downey, Con K K Stough, Michael Keane, Brook Shiferaw, Panagiota Kostakis, Yahya Shehabi
Ketamine hydrochloride elicits potent psychotomimetic and neurobehavioural effects which make it incompatible with driving; however, the direct effect on driving performance is yet to be assessed. Using an open label, within-subjects protocol, 15 males and 5 females (mean age = 30.8 years) were administered three fixed, stepwise increasing sub-anaesthetic doses of intravenous (IV) ketamine solution [(i) 8 mg/h IV infusion plus 30 mg bolus, (ii) 12 mg/h IV infusion and (iii) 20 mg/h infusion]. Whole blood ketamine and norketamine concentrations were determined at each treatment step and at 2 h post-infusion...
May 18, 2018: Progress in Neuro-psychopharmacology & Biological Psychiatry
https://www.readbyqxmd.com/read/29782928/a-mathematical-approach-to-effects-of-ctls-on-cancer-virotherapy-in-the-second-injection-of-virus
#5
A Ashyani, O RabieiMotlagh, H M Mohammadinezhad
This paper proposes a planar delay differential equation for cancer virotherapy. The model simulates the situation in which an oncolytic virus is injected for the second time, and the immune system suppresses the viral infection with a time delay. Our purpose is to provide theoretical conditions so that the therapy can be continued successfully. With the help of the characteristic equation, we examine the singularities and their local stability. Hopf bifurcation is also investigated around the endemic singularity...
May 18, 2018: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/29782927/modeling-the-odor-landscape-resulting-from-the-pumping-behavior-of-bivalve-clams-in-the-presence-of-predators
#6
A Alvarez
Motivated by experimental findings, a computational fluid dynamics (CFD) model was used to investigate whether the clam Mercenaria mercenaria may alter its cue downstream variability by an exhalant random pumping behavior. This behavior was hypothesized to occur in the presence of predator chemical signals in order to prevent successful tracking by the predator. Simulated downstream flow and mixing conditions derived from the random nature of the clam exhalant jet in a crossflow were analyzed by computing an intermittency factor, determining the field of finite-time Lyapunov exponents (FTLEs) and identifying the resulting Lagrangian coherent structures (LCSs)...
May 18, 2018: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/29782833/insights-into-stabilizing-forces-in-amyloid-fibrils-of-differing-sizes-from-polarizable-molecular-dynamics-simulations
#7
Darcy S Davidson, Anne M Brown, Justin A Lemkul
Pathological aggregation of amyloid-forming proteins is a hallmark of a number of human diseases, including Alzheimer's, type 2 diabetes, Parkinson's, and more. Despite having very different primary amino acid sequences, these amyloid proteins form similar supramolecular, fibril structures that are highly resilient to physical and chemical denaturation. To better understand the structural stability of disease-related amyloids and to gain a greater understanding of factors that stabilize functional amyloid assemblies, insights into tertiary and quaternary interactions are needed...
May 18, 2018: Journal of Molecular Biology
https://www.readbyqxmd.com/read/29782644/on-the-relationship-between-phylogenetic-diversity-and-trait-diversity
#8
Caroline M Tucker, T Jonathan Davies, Marc W Cadotte, William D Pearse
Niche differences are key to understanding the distribution and structure of biodiversity. To examine niche differences, we must first characterize how species occupy niche space, and two approaches are commonly used in the ecological literature. The first uses species traits to estimate multivariate trait space (so-called functional trait diversity, FD); the second quantifies the amount of time or evolutionary history captured by a group of species (phylogenetic diversity, PD). It is often-but controversially-assumed that these putative measures of niche space are at a minimum correlated and perhaps redundant, since more evolutionary time allows for greater accumulation of trait changes...
May 21, 2018: Ecology
https://www.readbyqxmd.com/read/29782617/patient-specific-neurosurgical-phantom-assessment-of-visual-quality-accuracy-and-scaling-effects
#9
Felipe Wilker Grillo, Victor Hugo Souza, Renan Hiroshi Matsuda, Carlo Rondinoni, Theo Zeferino Pavan, Oswaldo Baffa, Helio Rubens Machado, Antonio Adilton Oliveira Carneiro
Background: Training in medical education depends on the availability of standardized materials that can reliably mimic the human anatomy and physiology. One alternative to using cadavers or animal bodies is to employ phantoms or mimicking devices. Styrene-ethylene/butylene-styrene (SEBS) gels are biologically inert and present tunable properties, including mechanical properties that resemble the soft tissue. Therefore, SEBS is an alternative to develop a patient-specific phantom, that provides real visual and morphological experience during simulation-based neurosurgical training...
2018: 3D Print Med
https://www.readbyqxmd.com/read/29782584/including-traffic-jam-avoidance-in-an-agent-based-network-model
#10
Christian Hofer, Georg Jäger, Manfred Füllsack
Background: Understanding traffic is an important challenge in different scientific fields. While there are many approaches to constructing traffic models, most of them rely on origin-destination data and have difficulties when phenomena should be investigated that have an effect on the origin-destination matrix. Methods: A macroscopic traffic model is introduced that is novel in the sense that no origin-destination data are required as an input. This information is generated from mobility behavior data using a hybrid approach between agent-based modeling to find the origin and destination points of each vehicle and network techniques to find efficiently the routes most likely used to connect those points...
2018: Computational social networks
https://www.readbyqxmd.com/read/29782540/monte-carlo-simulations-of-microtubule-arrays-the-critical-roles-of-rescue-transitions-the-cell-boundary-and-tubulin-concentration-in-shaping-microtubule-distributions
#11
Lynne Cassimeris, Jessica C Leung, David J Odde
Microtubules are dynamic polymers required for a number of processes, including chromosome movement in mitosis. While regulators of microtubule dynamics have been well characterized, we lack a convenient way to predict how the measured dynamic parameters shape the entire microtubule system within a cell, or how the system responds when specific parameters change in response to internal or external signals. Here we describe a Monte Carlo model to simulate an array of dynamic microtubules from parameters including the cell radius, total tubulin concentration, microtubule nucleation rate from the centrosome, and plus end dynamic instability...
2018: PloS One
https://www.readbyqxmd.com/read/29782471/new-approach-in-acne-therapy-a-specific-bacteriocin-activity-and-a-targeted-anti-il-8-property-in-just-1-probiotic-strain-the-l-salivarius-ls03
#12
Francesca Deidda, Angela Amoruso, Stefania Nicola, Teresa Graziano, Marco Pane, Luca Mogna
GOALS: The aim of this research was to assess the antibacterial activity of Lactobacillus salivarius LS03 (DSM 22776) against Propionibacterium acnes and its anti-inflammatory properties by inhibiting P. acnes-induced interleukin-8 (IL-8) release. BACKGROUND: Acne is the most common skin disease, causing significant psychosocial problems for those afflicted. Currently available agents for acne treatment, such as oral antibiotics, have limited use. Thus, development of novel agents to treat this disease is needed...
May 18, 2018: Journal of Clinical Gastroenterology
https://www.readbyqxmd.com/read/29782219/soft-robotics-academic-insights-and-perspectives-through-bibliometric-analysis
#13
Guanjun Bao, Hui Fang, Lingfeng Chen, Yuehua Wan, Fang Xu, Qinghua Yang, Libin Zhang
Soft robotics is of growing interest in the robot community as well as in public media, and there is an increase in the quality and quantity of publications related to this topic. To formally elaborate this growth, we have used a bibliometric analysis to evaluate the publications in the field from 1990 to 2017 based on the Science Citation Index Expanded database. We present a detailed overview and discussion based on keywords, citation, h-index, year, journal, institution, country, author, and review articles...
May 21, 2018: Soft Robotics
https://www.readbyqxmd.com/read/29782173/field-directed-self-assembly-of-mutually-polarizable-nanoparticles
#14
Zachary M Sherman, Dipanjan Ghosh, James W Swan
Directed assembly of dielectric and paramagnetic nanoparticles can be used to synthesize diverse functional materials that polarize in response to an externally applied electric or magnetic field. However, theories capable of predicting the self-assembled states are lacking. In the proposed work, we develop a complete thermodynamic description of such assemblies for spherical nanoparticles. We show how an important physical feature of these types of particles, mutual polarization, sculpts the free energy landscape and has a remarkably strong influence on the nature of the self-assembled states...
May 21, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29782151/a-computational-workflow-for-the-automated-generation-of-models-of-genetic-designs
#15
Göksel Mısırlı, Tramy Nguyen, James Alastair McLaughlin, Prashant Vaidyanathan, Timothy Jones, Douglas Densmore, Chris J Myers, Anil Wipat
Computational models are essential to engineer predictable biological systems and to scale up this process for complex systems. Computational modelling often requires expert knowledge and data to build models. Clearly, manual creation of models is not scalable for large designs. Despite several automated model construction approaches, computational methodologies to bridge knowledge in design repositories and the process of creating computational models has still not been established. This paper describes a workflow for automatic generation of computational models of genetic circuits from data stored in design repositories using existing standards...
May 21, 2018: ACS Synthetic Biology
https://www.readbyqxmd.com/read/29782027/an-improved-detection-limit-and-working-range-of-lateral-flow-assays-based-on-a-mathematical-model
#16
Zhi Liu, Zhiguo Qu, Ruihua Tang, Xiaocong He, Hui Yang, Dan Bai, Feng Xu
Lateral flow assays (LFAs) have attracted considerable attention in biomedical diagnostics. However, it's still challenging to achieve a high detection sensitivity and extensive working range, mainly because the underlying mechanism of complex reaction processes in LFAs remains unclear. Many mathematical models have been developed to analyze the complex reaction processes, which are only qualitative with limited guidance for LFA design. Now, a semi-quantitative convection-diffusion-reaction model is developed by considering the kinetics of renaturation of nucleic acids and the model is validated by our experiments...
May 21, 2018: Analyst
https://www.readbyqxmd.com/read/29781710/a-computationally-more-efficient-and-more-accurate-stepwise-approach-for-correcting-for-sampling-error-and-measurement-error
#17
Steffen Zitzmann
Over the last decade or two, multilevel structural equation modeling (ML-SEM) has become a prominent modeling approach in the social sciences because it allows researchers to correct for sampling and measurement errors and thus to estimate the effects of Level 2 (L2) constructs without bias. Because the latent variable modeling software Mplus uses maximum likelihood (ML) by default, many researchers in the social sciences have applied ML to obtain estimates of L2 regression coefficients. However, one drawback of ML is that covariance matrices of the predictor variables at L2 tend to be degenerate, and thus, estimates of L2 regression coefficients tend to be rather inaccurate when sample sizes are small...
May 21, 2018: Multivariate Behavioral Research
https://www.readbyqxmd.com/read/29781638/a-model-based-test-for-treatment-effects-with-probabilistic-classifications
#18
Daniel R Cavagnaro, Clintin P Davis-Stober
Within modern psychology, computational and statistical models play an important role in describing a wide variety of human behavior. Model selection analyses are typically used to classify individuals according to the model(s) that best describe their behavior. These classifications are inherently probabilistic, which presents challenges for performing group-level analyses, such as quantifying the effect of an experimental manipulation. We answer this challenge by presenting a method for quantifying treatment effects in terms of distributional changes in model-based (i...
May 21, 2018: Psychological Methods
https://www.readbyqxmd.com/read/29781637/a-comparison-of-several-approaches-for-controlling-measurement-error-in-small-samples
#19
Victoria Savalei
It is well known that methods that fail to account for measurement error in observed variables, such as regression and path analysis (PA), can result in poor estimates and incorrect inference. On the other hand, methods that fully account for measurement error, such as structural equation modeling with latent variables and multiple indicators, can produce highly variable estimates in small samples. This article advocates a family of intermediate models for small samples (N < 200), referred to as single indicator (SI) models...
May 21, 2018: Psychological Methods
https://www.readbyqxmd.com/read/29781626/on-selecting-evidence-to-test-hypotheses-a-theory-of-selection-tasks
#20
Marco Ragni, Ilir Kola, Philip N Johnson-Laird
How individuals choose evidence to test hypotheses is a long-standing puzzle. According to an algorithmic theory that we present, it is based on dual processes: individuals' intuitions depending on mental models of the hypothesis yield selections of evidence matching instances of the hypothesis, but their deliberations yield selections of potential counterexamples to the hypothesis. The results of 228 experiments using Wason's selection task corroborated the theory's predictions. Participants made dependent choices of items of evidence: the selections in 99 experiments were significantly more redundant (using Shannon's measure) than those of 10,000 simulations of each experiment based on independent selections...
May 21, 2018: Psychological Bulletin
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