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https://www.readbyqxmd.com/read/28636047/decoding-the-regulatory-mechanism-of-glucose-and-insulin-induced-phosphatidylinositol-3-4-5-trisphosphate-dynamics-in-%C3%AE-cells
#1
Tagari Samanta, Peeyush Sharma, Dwijendra Kukri, Sandip Kar
In MIN6 pancreatic β-cells, glucose and insulin act in a synergistic manner to regulate the dynamics of Phosphatidylinositol (3,4,5)-trisphosphate (PIP3). However, the precise regulatory mechanism behind such an experimentally observed synergy is poorly understood. In this article, we propose a phenomenological mathematical model for studying the glucose and insulin driven PIP3 activation dynamics under various stimulatory conditions to unfold the mechanism responsible for the observed synergy. The modeling study reveals that the experimentally observed oscillation in PIP3 dynamics with disparate time scales for different external glucose doses is mainly orchestrated by the complex dynamic regulation of cytosolic Ca(2+) in β-cells...
June 21, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28635569/stratification-model-based-on-early-postprostatectomy-prostate-specific-antigen-kinetics-may-help-to-reduce-the-risk-of-overtreatment-in-candidates-for-adjuvant-radiotherapy
#2
Stepan Vesely, Ladislav Jarolim, Marek Schmidt, Joana Do Carmo Silva, Katerina Duskova, Marko Babjuk
OBJECTIVE: The aim of this study was to construct a stratification model based on early postoperative kinetics of prostate-specific antigen (PSA) to select the most suitable high-risk patients for early intervention after radical prostatectomy (RP). MATERIALS AND METHODS: The study evaluated 205 men who had undergone RP without any adjuvant treatment. All of the patients had positive surgical margins, extracapsular extension and/or seminal vesicle invasion. The patients underwent multiple ultrasensitive PSA measurements on days 14, 30, 60 and 90 after RP, and subsequently at 3 month intervals...
February 24, 2017: Scandinavian Journal of Urology
https://www.readbyqxmd.com/read/28634784/attentional-weights-in-vision-as-products-of-spatial-and-nonspatial-components
#3
Maria Nordfang, Camilla Staugaard, Claus Bundesen
The relationship between visual attentional selection of items in particular spatial locations and selection by nonspatial criteria was investigated in a partial report experiment with report of letters (as many as possible) from brief postmasked exposures of circular arrays of letters and digits. The data were fitted by mathematical models based on Bundesen's (Psychological Review, 97, 523-547, 1990) theory of visual attention (TVA). Both attentional weights of targets (letters) and attentional weights of distractors (digits) showed strong variations across the eight possible target locations, but for each of the ten participants, the ratio of the weight of a distractor at a given location to the weight of a target at the same location was approximately constant...
June 20, 2017: Psychonomic Bulletin & Review
https://www.readbyqxmd.com/read/28634351/a-dynamical-model-for-activating-and-silencing-the-mitotic-checkpoint
#4
Richard Henze, Peter Dittrich, Bashar Ibrahim
The spindle assembly checkpoint (SAC) is an evolutionarily conserved mechanism, exclusively sensitive to the states of kinetochores attached to microtubules. During metaphase, the anaphase-promoting complex/cyclosome (APC/C) is inhibited by the SAC but it rapidly switches to its active form following proper attachment of the final spindle. It had been thought that APC/C activity is an all-or-nothing response, but recent findings have demonstrated that it switches steadily. In this study, we develop a detailed mathematical model that considers all 92 human kinetochores and all major proteins involved in SAC activation and silencing...
June 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28634131/cost-effectiveness-of-pre-versus-post-liver-transplant-hepatitis-c-treatment-with-direct-acting-antivirals
#5
Sumeyye Samur, Brian Kues, Turgay Ayer, Mark S Roberts, Fasiha Kanwal, Chin Hur, Drew Michael S Donnell, Raymond T Chung, Jagpreet Chhatwal
BACKGROUND & AIMS: Oral direct-acting antivirals (DAAs) for hepatitis C virus (HCV) treatment offer new hope to both pre- and post-liver transplant (LT) patients. However, whether to treat HCV patients pre- versus post-LT is not clear, as treatment can improve liver function but could reduce the chance of receiving a LT while on the waiting list. Our objective was to evaluate the cost-effectiveness of pre-LT versus post-LT HCV treatment with oral DAAs in decompensated cirrhotic patients on the LT waiting list...
June 17, 2017: Clinical Gastroenterology and Hepatology
https://www.readbyqxmd.com/read/28633990/cellular-gauge-symmetry-and-the-li-organization-principle-a-mathematical-addendum-quantifying-energetic-dynamics-in-physical-and-biological-systems-through-a-simple-geometric-tool-and-geodetic-curves
#6
REVIEW
Alexander Yurkin, Arturo Tozzi, James F Peters, Pedro C Marijuán
The present Addendum complements the accompanying paper "Cellular Gauge Symmetry and the Li Organization Principle"; it illustrates a recently-developed geometrical physical model able to assess electronic movements and energetic paths in atomic shells. The model describes a multi-level system of circular, wavy and zigzag paths which can be projected onto a horizontal tape. This model ushers in a visual interpretation of the distribution of atomic electrons' energy levels and the corresponding quantum numbers through rather simple tools, such as compasses, rulers and straightforward calculations...
June 17, 2017: Progress in Biophysics and Molecular Biology
https://www.readbyqxmd.com/read/28633613/thermal-effects-on-cognition-a-new-quantitative-synthesis
#7
José Ignacio López-Sánchez, P A Hancock
There is little doubt that increases in thermal load beyond the thermo-neutral state prove progressively stressful to all living organisms. Increasing temperatures across the globe represent in some locales, and especially for outdoors workers, a significant source of such chronic load increase. However, increases in thermal load affect cognition as well as physical work activities. Such human cognition has perennially been viewed as the primary conduit through which to solve many of the iatrogenic challenges we now face...
June 20, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28633306/multivariate-phylogenetic-comparative-methods-evaluations-comparisons-and-recommendations
#8
Dean C Adams, Michael L Collyer
Recent years have seen increased interest in phylogenetic comparative analyses of multivariate datasets, but to date the varied proposed approaches have not been extensively examined. Here we review the mathematical properties required of any multivariate method, and specifically evaluate existing multivariate phylogenetic comparative methods in this context. Phylogenetic comparative methods based on the full multivariate likelihood are robust to levels of covariation among trait dimensions and are insensitive to the orientation of the dataset, but display increasing model misspecification as the number of trait dimensions increases...
June 13, 2017: Systematic Biology
https://www.readbyqxmd.com/read/28632743/in-silico-assessment-of-the-effects-of-quinidine-disopyramide-and-e-4031-on-short-qt-syndrome-variant-1-in-the-human-ventricles
#9
Cunjin Luo, Kuanquan Wang, Henggui Zhang
AIMS: Short QT syndrome (SQTS) is an inherited disorder associated with abnormally abbreviated QT intervals and an increased incidence of atrial and ventricular arrhythmias. SQT1 variant (linked to the rapid delayed rectifier potassium channel current, IKr) of SQTS, results from an inactivation-attenuated, gain-of-function mutation (N588K) in the KCNH2-encoded potassium channels. Pro-arrhythmogenic effects of SQT1 have been well characterized, but less is known about the possible pharmacological antiarrhythmic treatment of SQT1...
2017: PloS One
https://www.readbyqxmd.com/read/28631947/predominant-contribution-of-l-type-cav1-2-channel-stimulation-to-impaired-intracellular-calcium-and-cerebral-artery-vasoconstriction-in-diabetic-hyperglycemia
#10
Stefano Morotti, Madeline Nieves-Cintrón, Matthew A Nystoriak, Manuel F Navedo, Eleonora Grandi
Enhanced L-type Ca(2+) channel (LTCC) activity in arterial myocytes contributes to vascular dysfunction during diabetes. Modulation of LTCC activity under hyperglycemic conditions could result from membrane potential-dependent and independent mechanisms. We have demonstrated that elevations in extracellular glucose (HG), similar to hyperglycemic conditions during diabetes, stimulate LTCC activity through phosphorylation of CaV1.2 at serine 1928. Prior studies have also shown that HG can suppress the activity of K(+) channels in arterial myocytes, which may contribute to vasoconstriction via membrane depolarization...
February 10, 2017: Channels
https://www.readbyqxmd.com/read/28631803/a-gompertz-model-approach-to-microbial-inactivation-kinetics-by-high-pressure-processing-hpp-model-selection-and-experimental-validation
#11
Vinicio Serment-Moreno, Claudio Fuentes, José Antonio Torres, Jorge Welti-Chanes
A recently proposed Gompertz model (GMPZ) approach describing microbial inactivation kinetics by high-pressure processing (HPP) incorporated the initial microbial load (N0 ) and lower microbial quantification limit (Nlim ), and simplified the dynamic effects of come-up time (CUT). The inactivation of Listeria innocua in milk by HPP treatments at 300, 400, 500, and 600 MPa and pressure holding times (thold ) ≤10 min was determined experimentally to validate this model approach. Models based on exponential, logistic-exponential, and inverse functions were evaluated to describe the effect of pressure on the lag time (λ) and maximum inactivation rate (μmax ), whereas the asymptote difference (A) was fixed as A = log10 (N0 /Nlim )...
June 20, 2017: Journal of Food Science
https://www.readbyqxmd.com/read/28631521/on-the-die-compaction-of-powders-used-in-pharmaceutics
#12
G Aryanpour, M Farzaneh
Die compaction is widely used in the compaction of pharmaceutical powders (tableting). It is well known that the powder densification is a result of particle rearrangement and particle deformation. The former is considered to be the governing mechanism of densification in an initial stage of compaction and the latter is regarded as the governing mechanism in the compaction at the higher pressure range. As a more realistic assumption, one can consider that a simultaneous performance of both the rearrangement and deformation mechanisms takes place from the beginning of compaction...
June 20, 2017: Pharmaceutical Development and Technology
https://www.readbyqxmd.com/read/28631383/benford-s-law-for-quality-assurance-of-manner-of-death-counts-in-small-and-large-databases
#13
Jeremy Daniels, Samantha-Jo Caetano, Dirk Huyer, Andrew Stephen, John Fernandes, Alice Lytwyn, Fred M Hoppe
To assess if Benford's law, a mathematical law used for quality assurance in accounting, can be applied as a quality assurance measure for the manner of death determination. We examined a regional forensic pathology service's monthly manner of death counts (N = 2352) from 2011 to 2013, and provincial monthly and weekly death counts from 2009 to 2013 (N = 81,831). We tested whether each dataset's leading digit followed Benford's law via the chi-square test. For each database, we assessed whether number 1 was the most common leading digit...
June 20, 2017: Journal of Forensic Sciences
https://www.readbyqxmd.com/read/28631107/non-invasive-coronary-wave-intensity-analysis
#14
Christopher J Broyd, Fausto Rigo, Justin Davies
Wave intensity analysis is calculated from simultaneously acquired measures of pressure and flow. Its mathematical computation produces a profile that provides quantitative information on the energy exchange driving blood flow acceleration and deceleration. Within the coronary circulation it has proven most useful in describing the wave that originates from the myocardium and that is responsible for driving the majority of coronary flow, labelled the backward decompression wave. Whilst this wave has demonstrated valuable insights into the pathogenic processes of a number of disease states, its measurement is hampered by its invasive necessity...
June 19, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/28630885/bayesian-framework-inspired-no-reference-region-of-interest-quality-measure-for-brain-mri-images
#15
Michael Osadebey, Marius Pedersen, Douglas Arnold, Katrina Wendel-Mitoraj
We describe a postacquisition, attribute-based quality assessment method for brain magnetic resonance imaging (MRI) images. It is based on the application of Bayes theory to the relationship between entropy and image quality attributes. The entropy feature image of a slice is segmented into low- and high-entropy regions. For each entropy region, there are three separate observations of contrast, standard deviation, and sharpness quality attributes. A quality index for a quality attribute is the posterior probability of an entropy region given any corresponding region in a feature image where quality attribute is observed...
April 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28630826/predicting-the-effects-of-interventions-a-tutorial-on-the-disequilibrium-model
#16
Kenneth W Jacobs, Zachary H Morford, James E King, Linda J Hayes
The disequilibrium approach to reinforcement and punishment, derived from the probability-differential hypothesis and response deprivation hypothesis, provides a number of potentially useful mathematical models for practitioners. The disequilibrium approach and its accompanying models have proven effective in the prediction and control of behavior, yet they have not been fully espoused and integrated into clinical practice. The purpose of this tutorial is to detail the disequilibrium approach and adapt its mathematical models for use as a tool in applied settings...
June 2017: Behavior Analysis in Practice
https://www.readbyqxmd.com/read/28630667/evaluation-of-radical-scavenging-system-in-amoeba-chaos-carolinense-during-nutrient-deprivation
#17
Yuru Deng, Edlyn Li-Hui Lee, Ketpin Chong, Zakaria A Almsherqi
The frequent appearance of non-lamellar membrane arrangements such as cubic membranes (CMs) in cells under stressed or pathological conditions points to an intrinsic cellular response mechanism. CM represents highly curved, three-dimensional nano-periodic structures that correspond to mathematically well-defined triply periodic minimal surfaces. Specifically, cellular membrane may transform into CM organization in response to pathological, inflammatory and oxidative stress conditions. CM organization, thus, may provide an advantage to cope with various types of stress...
August 6, 2017: Interface Focus
https://www.readbyqxmd.com/read/28630527/a-promising-approach-to-integrally-evaluate-the-disease-outcome-of-cerebral-ischemic-rats-based-on-multiple-biomarker-crosstalk
#18
Guimei Ran, Yixuan Wang, Haochen Liu, Chunxiang Wei, Tao Zhu, Haidong Wang, Hua He, Xiaoquan Liu
PURPOSE: The study was designed to evaluate the disease outcome based on multiple biomarkers related to cerebral ischemia. METHODS: Rats were randomly divided into sham, permanent middle cerebral artery occlusion, and edaravone-treated groups. Cerebral ischemia was induced by permanent middle cerebral artery occlusion surgery in rats. To form a simplified crosstalk network, the related multiple biomarkers were chosen as S100β, HIF-1α, IL-1β, PGI2, TXA2, and GSH-Px...
2017: Disease Markers
https://www.readbyqxmd.com/read/28630524/a-martingale-analysis-of-first-passage-times-of-time-dependent-wiener-diffusion-models
#19
Vaibhav Srivastava, Samuel F Feng, Jonathan D Cohen, Naomi Ehrich Leonard, Amitai Shenhav
Research in psychology and neuroscience has successfully modeled decision making as a process of noisy evidence accumulation to a decision bound. While there are several variants and implementations of this idea, the majority of these models make use of a noisy accumulation between two absorbing boundaries. A common assumption of these models is that decision parameters, e.g., the rate of accumulation (drift rate), remain fixed over the course of a decision, allowing the derivation of analytic formulas for the probabilities of hitting the upper or lower decision threshold, and the mean decision time...
April 2017: Journal of Mathematical Psychology
https://www.readbyqxmd.com/read/28630490/pyroptosis-superinfection-and-the-maintenance-of-the-latent-reservoir-in-hiv-1-infection
#20
Dominik Wodarz, David N Levy
A long-lived reservoir of latently infected T cells prevents antiretroviral therapy from eliminating HIV-1 infection. Furthering our understanding of the dynamics of latency generation and maintenance is therefore vital to improve treatment outcome. Using mathematical models and experiments, we suggest that the death of latently infected cells brought about by pyroptosis, or to a lesser extent by superinfection, might be key mechanisms to account for the size and composition of the latent reservoir. Pyroptosis is a form of cell death that occurs in a resting (and thus latently infected) T cell when a productively infected cell attempts cell-to-cell transmission of virus...
June 19, 2017: Scientific Reports
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