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https://www.readbyqxmd.com/read/28445762/analysis-of-active-transport-by-fluorescence-recovery-after-photobleaching
#1
Maria-Veronica Ciocanel, Jill A Kreiling, James A Gagnon, Kimberly L Mowry, Björn Sandstede
Fluorescence recovery after photobleaching (FRAP) is a well-established experimental technique to study binding and diffusion of molecules in cells. Although a large number of analytical and numerical models have been developed to extract binding and diffusion rates from FRAP recovery curves, active transport of molecules is typically not included in the existing models that are used to estimate these rates. Here we present a validated numerical method for estimating diffusion, binding/unbinding rates, and active transport velocities using FRAP data that captures intracellular dynamics through partial differential equation models...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28444939/continuous-ambulatory-peritoneal-dialysis-ascitic-and-pleural-body-fluids-evaluation-with-the-mindray-bc-6800-hematology-analyzer
#2
Oscar Fuster, Belinda Andino, Amparo Pardo, Begoña Laiz
BACKGROUND: Accurate evaluation of hematology analyzers is recommended before these devices can be broadly introduced for the routine testing of continuous ambulatory peritoneal dialysis (CAPD), ascitic, and pleural fluids. METHODS: We evaluated the performance of Mindray BC-6800 for white blood cell (WBC) and differential cell count in 50 CAPD, 60 ascitic and 40 pleural compared with manual microscopy. Within-run precision, limit of blank (LoB), limit of detection (LoD), limit of quantitation (LoQ), and carryover were assessed...
April 26, 2017: Journal of Clinical Laboratory Analysis
https://www.readbyqxmd.com/read/28444498/competition-of-multiple-species-in-advective-environments
#3
Olga Vasilyeva
We study the effect of changes in flow speed on competition of an arbitrary number of species living in advective environments, such as streams and rivers. We begin with a spatial Lotka-Volterra model which is described by n reaction-diffusion-advection equations with Danckwerts boundary conditions. Using the dominant eigenvalue [Formula: see text] of the diffusion-advection operator subject to boundary conditions, we reduce the model to a system of ordinary differential equations. We impose a "transitive arrangement" of the competitors in terms of their interspecific coefficients and growth rates, which means that in the absence of advection, we have the following situation: for all [Formula: see text], species i out-competes species j, while species j has higher intrinsic growth rate than species i...
April 25, 2017: Bulletin of Mathematical Biology
https://www.readbyqxmd.com/read/28443826/rebinding-in-biochemical-reactions-on-membranes
#4
Sean D Lawley, James Keener
The behavior of many biochemical processes depends crucially on molecules rapidly rebinding after dissociating. In the case of multisite protein modification, the importance of rebinding has been demonstrated both experimentally and through several recent computational studies involving stochastic spatial simulations. As rebinding stems from spatio-temporal correlations, theorists have resorted to models that explicitly include space to properly account for the effects of rebinding. However, for reactions in three space dimensions it was recently shown that well-mixed ordinary differential equation (ODE) models can incorporate rebinding by adding connections to the reaction network...
April 26, 2017: Physical Biology
https://www.readbyqxmd.com/read/28441909/the-perceived-quality-of-in-vehicle-auditory-signals-a-structural-equation-modeling-approach
#5
Chia-Fen Chi, Ratna Sari Dewi, Yopie Yutama Surbakti, Dong-Yu Hsieh
The current study applied Structural Equation Modelling to analyze the relationship among pitch, loudness, tempo and timbre and their relationship with perceived sound quality. Twenty-eight auditory signals of horn, indicator, door open warning, and parking sensor were collected from 11 car brands. Twenty-one experienced drivers were recruited to evaluate all sound signals with 11 semantic differential scales. The results indicate that for the continuous sounds, pitch, loudness, and timbre each had a direct impact on the perceived quality...
April 25, 2017: Ergonomics
https://www.readbyqxmd.com/read/28441647/subjective-memory-in-a-national-sample-predicting-psychological-well-being
#6
Jacqueline A Mogle, Nikki Hill, Caroline McDermott
BACKGROUND: Individual perception of memory performance (i.e., subjective memory) is assessed using a variety of approaches. This article focuses on 2 such approaches: (1) self-comparison assessments that attempt to capture changes in memory ability over a period of time and (2) age-anchored comparisons that assess how an individual perceives their memory in relation to others their age. These different types of assessment may relate to psychological well-being differently due to the underlying mechanisms of assessment...
April 26, 2017: Gerontology
https://www.readbyqxmd.com/read/28440047/mental-illness-in-bariatric-surgery-a-cohort-study-from-the-portal-network
#7
David Fisher, Karen J Coleman, David E Arterburn, Heidi Fischer, Ayae Yamamoto, Deborah R Young, Nancy E Sherwood, Connie Mah Trinacty, Kristina H Lewis
OBJECTIVE: To compare bariatric surgery outcomes according to preoperative mental illness category. METHODS: Electronic health record data from several US healthcare systems were used to compare outcomes of four groups of patients who underwent bariatric surgery in 2012 and 2013. These included the following: people with (1) no mental illness, (2) mild-to-moderate depression or anxiety, (3) severe depression or anxiety, and (4) bipolar, psychosis, or schizophrenia spectrum disorders...
May 2017: Obesity
https://www.readbyqxmd.com/read/28439020/mathematical-model-of-chronic-pancreatitis
#8
Wenrui Hao, Hannah M Komar, Phil A Hart, Darwin L Conwell, Gregory B Lesinski, Avner Friedman
Chronic pancreatitis (CP) is a progressive inflammatory disease of the pancreas, leading to its fibrotic destruction. There are currently no drugs that can stop or slow the progression of the disease. The etiology of the disease is multifactorial, whereas recurrent attacks of acute pancreatitis are thought to precede the development of CP. A better understanding of the pathology of CP is needed to facilitate improved diagnosis and treatment strategies for this disease. The present paper develops a mathematical model of CP based on a dynamic network that includes macrophages, pancreatic stellate cells, and prominent cytokines that are present at high levels in the CP microenvironment...
April 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28437850/public-perception-of-uncertainties-within-climate-change-science
#9
Vivianne H M Visschers
Climate change is a complex, multifaceted problem involving various interacting systems and actors. Therefore, the intensities, locations, and timeframes of the consequences of climate change are hard to predict and cause uncertainties. Relatively little is known about how the public perceives this scientific uncertainty and how this relates to their concern about climate change. In this article, an online survey among 306 Swiss people is reported that investigated whether people differentiate between different types of uncertainty in climate change research...
April 24, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
https://www.readbyqxmd.com/read/28436913/synchronization-of-reaction-diffusion-neural-networks-with-dirichlet-boundary-conditions-and-infinite-delays
#10
Yin Sheng, Hao Zhang, Zhigang Zeng
This paper is concerned with synchronization for a class of reaction-diffusion neural networks with Dirichlet boundary conditions and infinite discrete time-varying delays. By utilizing theories of partial differential equations, Green's formula, inequality techniques, and the concept of comparison, algebraic criteria are presented to guarantee master-slave synchronization of the underlying reaction-diffusion neural networks via a designed controller. Additionally, sufficient conditions on exponential synchronization of reaction-diffusion neural networks with finite time-varying delays are established...
April 17, 2017: IEEE Transactions on Cybernetics
https://www.readbyqxmd.com/read/28436911/sampled-data-fuzzy-control-for-nonlinear-coupled-parabolic-pde-ode-systems
#11
Zi-Peng Wang, Huai-Ning Wu, Han-Xiong Li
In this paper, a sampled-data fuzzy control problem is addressed for a class of nonlinear coupled systems, which are described by a parabolic partial differential equation (PDE) and an ordinary differential equation (ODE). Initially, the nonlinear coupled system is accurately represented by the Takagi-Sugeno (T-S) fuzzy coupled parabolic PDE-ODE model. Then, based on the T-S fuzzy model, a novel time-dependent Lyapunov functional is used to design a sampled-data fuzzy controller such that the closed-loop coupled system is exponentially stable, where the sampled-data fuzzy controller consists of the ODE state feedback and the PDE static output feedback under spatially averaged measurements...
April 17, 2017: IEEE Transactions on Cybernetics
https://www.readbyqxmd.com/read/28436272/moderation-of-the-effects-of-discrimination-induced-affective-responses-on-health-outcomes
#12
Meg Gerrard, Frederick X Gibbons, Mary E Fleischli, Carolyn E Cutrona, Michelle L Stock
OBJECTIVE: The goal of the study was to examine differential mediation of long-term effects of discrimination on health behaviour and health status by internalising (anxiety and depression) and externalising (hostility and anger), and to explore moderation of these effects, specifically, by the presence of support networks and coping tendencies. DESIGN: The current analyses employed structural equation modelling of five waves of data from Black female participants of the Family and Community Health Study over 11 years (M age 37-48)...
April 23, 2017: Psychology & Health
https://www.readbyqxmd.com/read/28434092/cyberbullying-victimization-and-adolescent-mental-health-evidence-of-differential-effects-by-sex-and-mental-health-problem-type
#13
Soyeon Kim, Scott R Colwell, Anna Kata, Michael H Boyle, Katholiki Georgiades
The use of electronic communication technologies has become a core method for adolescent communication. While there are many benefits to such technologies, cyberbullying has emerged as a potential harm. This study examines the association between cyberbullying and adolescent mental health problems and the extent to which this association differs by sex and mental health problem type. A clustered sample of 31,148 students in grades 6-12 (Female = 51.9%; 56.5% Caucasian, 10.2% South Asian) completed an anonymous survey asking their frequency of exposure to traditional forms of bullying, cyberbullying, and experiences of mental health problems over the past 6 months...
April 22, 2017: Journal of Youth and Adolescence
https://www.readbyqxmd.com/read/28433736/on-the-role-of-the-second-order-derivative-term-in-the-calculation-of-convergent-beam-diffraction-patterns
#14
S C Hillier, E T Robertson, G D Reid, R D Haynes, M D Robertson
The simulation of (scanning) transmission electron microscopy images and diffraction patterns is most often performed using the forward-scattering approximation where the second-order derivative term in z is assumed to be small with respect to the first-order derivative term in the modified Schrödinger equation. This assumption is very good at high incident electron energies, but breaks down at low energies. In order to study the differences between first- and second-order methods, convergent beam electron diffraction patterns were simulated for silicon at the [111] zone-axis orientation at 20 keV and compared using electron intensity difference maps and integrated intensity profiles...
April 12, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28433392/quantifying-rates-of-cell-migration-and-cell-proliferation-in-co-culture-barrier-assays-reveals-how-skin-and-melanoma-cells-interact-during-melanoma-spreading-and-invasion
#15
Parvathi Haridas, Catherine J Penington, Jacqui A McGovern, D L Sean McElwain, Matthew J Simpson
Malignant spreading involves the migration of cancer cells amongst other native cell types. For example, in vivo melanoma invasion involves individual melanoma cells migrating through native skin, which is composed of several distinct subpopulations of cells. Here, we aim to quantify how interactions between melanoma and fibroblast cells affect the collective spreading of a heterogeneous population of these cells in vitro. We perform a suite of circular barrier assays that includes: (i) monoculture assays with fibroblast cells; (ii) monoculture assays with SK-MEL-28 melanoma cells; and (iii) a series of co-culture assays initiated with three different ratios of SK-MEL-28 melanoma cells and fibroblast cells...
April 19, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28430512/simplifying-differential-equations-for-multiscale-feynman-integrals-beyond-multiple-polylogarithms
#16
Luise Adams, Ekta Chaubey, Stefan Weinzierl
In this Letter we exploit factorization properties of Picard-Fuchs operators to decouple differential equations for multiscale Feynman integrals. The algorithm reduces the differential equations to blocks of the size of the order of the irreducible factors of the Picard-Fuchs operator. As a side product, our method can be used to easily convert the differential equations for Feynman integrals which evaluate to multiple polylogarithms to an ϵ form.
April 7, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28427819/size-dependent-axial-instability-of-microtubules-surrounded-by-cytoplasm-of-a-living-cell-based-on-nonlocal-strain-gradient-elasticity-theory
#17
S Sahmani, M M Aghdam
Microtubules including tubulin heterodimers arranging in a parallel shape of cylindrical hollow plays an important role in the mechanical stiffness of a living cell. In the present study, the nonlocal strain gradient theory of elasticity including simultaneously the both nonlocality and strain gradient size dependency is put to use within the framework of a refined orthotropic shell theory with hyperbolic distribution of shear deformation to analyze the size-dependent buckling and postbuckling characteristics of microtubules embedded in cytoplasm under axial compressive load...
April 17, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28427670/estimation-of-the-distribution-of-low-intensity-ultrasound-mechanical-index-as-a-parameter-affecting-the-proliferation-of-spermatogonia-stem-cells-in-vitro
#18
Zeinab Hormozi Moghaddam, Manijhe Mokhtari-Dizaji, Mansoureh Movahedin, Mohammad Ehsan Ravari
Considering the use of physical and mechanical stimulation, such as low-intensity ultrasound for proliferation and differentiation of stem cells, it is essential to understand the physical and acoustical mechanisms of acoustic waves in vitro. Mechanical index is used for quantifying acoustic cavitation and the relationship between acoustic pressure and the frequency. In this study, modeling of the mechanical index was applied to provide treatment protocol and to understand the effective physical processes on reproducibility of stem cells...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427300/object-decision-test-borb-normative-data-for-the-adult-quebec-population-and-performance-in-alzheimer-s-disease-and-the-semantic-variant-of-primary-progressive-aphasia
#19
Alexandre St-Hilaire, Marie-Claude Blackburn, Maximiliano A Wilson, Robert Jr Laforce, Carol Hudon, Joël Macoir
Object decision (OD) test is one subtest of the Birmingham Object Recognition Battery (BORB). It is useful for differential diagnosis among several neurodegenerative diseases. However, normative data provided with this battery count on very few subjects and do not control for the effect of age, which limits interpretability. The purpose of Study 1 was to provide normative data for the OD test of the BORB (version A-hard). The objectives of Study 2 were to establish the diagnostic validity of this task and predictive validity of the normative data in the case of the semantic variant of primary progressive aphasia (svPPA) and Alzheimer's disease (AD)...
April 21, 2017: Neuropsychology, Development, and Cognition. Section B, Aging, Neuropsychology and Cognition
https://www.readbyqxmd.com/read/28426333/existence-and-uniqueness-for-a-coupled-pde-model-for-motor-induced-microtubule-organization
#20
Thomas Hillen, Diana White, Gerda de Vries, Adriana Dawes
Microtubules (MTs) are protein filaments that provide structure to the cytoskeleton of cells and a platform for the movement of intracellular substances. The spatial organization of MTs is crucial for a cell's form and function. MTs interact with a class of proteins called motor proteins that can transport and position individual filaments, thus contributing to overall organization. In this paper, we study the mathematical properties of a coupled partial differential equation (PDE) model, introduced by White et al...
April 20, 2017: Journal of Biological Dynamics
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