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https://www.readbyqxmd.com/read/28434057/predictive-control-of-intersegmental-tarsal-movements-in-an-insect
#1
Alicia Costalago-Meruelo, David M Simpson, Sandor M Veres, Philip L Newland
In many animals intersegmental reflexes are important for postural and movement control but are still poorly undesrtood. Mathematical methods can be used to model the responses to stimulation, and thus go beyond a simple description of responses to specific inputs. Here we analyse an intersegmental reflex of the foot (tarsus) of the locust hind leg, which raises the tarsus when the tibia is flexed and depresses it when the tibia is extended. A novel method is described to measure and quantify the intersegmental responses of the tarsus to a stimulus to the femoro-tibial chordotonal organ...
April 22, 2017: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/28434023/developing-a-statistically-powerful-measure-for-quartet-tree-inference-using-phylogenetic-identities-and-markov-invariants
#2
Jeremy G Sumner, Amelia Taylor, Barbara R Holland, Peter D Jarvis
Recently there has been renewed interest in phylogenetic inference methods based on phylogenetic invariants, alongside the related Markov invariants. Broadly speaking, both these approaches give rise to polynomial functions of sequence site patterns that, in expectation value, either vanish for particular evolutionary trees (in the case of phylogenetic invariants) or have well understood transformation properties (in the case of Markov invariants). While both approaches have been valued for their intrinsic mathematical interest, it is not clear how they relate to each other, and to what extent they can be used as practical tools for inference of phylogenetic trees...
April 22, 2017: Journal of Mathematical Biology
https://www.readbyqxmd.com/read/28433947/maximum-likelihood-estimation-of-cardiac-fiber-bundle-orientation-from-arbitrarily-spaced-diffusion-weighted-images
#3
Andreas Nagler, Cristóbal Bertoglio, Christian T Stoeck, Sebastian Kozerke, Wolfgang A Wall
We propose an estimation scheme for local fiber bundle direction in the left ventricle directly from gray values of arbitrarily spaced cardiac diffusion weighted images (DWI). The approach is based on a parametric and space-dependent mathematical representation of the myocardial fiber bundle orientation and hence the diffusion tensor (DT) for the ventricular geometry. By solving a nonlinear inverse problem derived from a maximum likelihood estimator, the degrees of freedom of the fiber and DT model can be estimated from the measured gray values of the DWIs...
April 4, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/28433439/cardiac-amyloidosis-shows-decreased-diastolic-function-as-assessed-by-echocardiographic-parameterized-diastolic-filling
#4
Katrin Salman, Peter A Cain, Benjamin T Fitzgerald, Martin G Sundqvist, Martin Ugander
Cardiac amyloidosis is a rare but serious condition with poor survival. One of the early findings by echocardiography is impaired diastolic function, even before the development of cardiac symptoms. Early diagnosis is important, permitting initiation of treatment aimed at improving survival. The parameterized diastolic filling (PDF) formalism entails describing the left ventricular filling pattern during early diastole using the mathematical equation for the motion of a damped harmonic oscillator. We hypothesized that echocardiographic PDF analysis could detect differences in diastolic function between patients with amyloidosis and controls...
April 19, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28433162/tocopheryl-acetate-release-from-microcapsules-of-waxy-maize-starch
#5
Naksit Panyoyai, Robert A Shanks, Stefan Kasapis
Diffusion coefficients are utilised to provide a realistic approach in the quantification of mass transport phenomena, which are important for the delivery of bioactivity from high-solid biopolymer systems. Following this mechanistic consideration, we employ spray drying to produce microcapsules of waxy maize starch that suspend homogeneously tocopheryl acetate. An array of physicochemical techniques including dynamic oscillation in-shear or compression mode, microDSC, WAXD, FTIR, scanning electron or optical microscopy, and UV-vis assays were utilised to relate structural properties of the macromolecular network to diffusivity of the bioactive compound...
July 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28433148/mechanics-and-transport-phenomena-in-agarose-based-hydrogels-studied-by-compression-relaxation-tests
#6
Diego Caccavo, Sara Cascone, Serena Poto, Gaetano Lamberti, Anna Angela Barba
Hydrogels are widespread materials, used in several frontier fields, due to their peculiar behavior: they couple solvent mass transport to system mechanics, exhibiting viscoelastic and poroelastic characteristics. The full understanding of this behavior is crucial to correctly design such complex systems. In this study agarose gels has been investigated through experimental stress-relaxation tests and with the aid of a 3D poroviscoelastic model. At the investigated experimental conditions, the agarose gels samples show a prevalent viscoelastic behavior, revealing limited water transport and an increase of the stiffness as well as of the relaxation time along with the polymer concentration...
July 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28432953/new-and-practical-mathematical-model-of-membrane-fouling-in-an-aerobic-submerged-membrane-bioreactor
#7
Mst Fazana Rahman Zuthi, Wenshan Guo, Huu Hao Ngo, Duc Long Nghiem, Faisal I Hai, Siqing Xia, Jianxin Li, Jixiang Li, Yi Liu
This study aimed to develop a practical semi-empirical mathematical model of membrane fouling that accounts for cake formation on the membrane and its pore blocking as the major processes of membrane fouling. In the developed model, the concentration of mixed liquor suspended solid is used as a lumped parameter to describe the formation of cake layer including the biofilm. The new model considers the combined effect of aeration and backwash on the foulants' detachment from the membrane. New exponential coefficients are also included in the model to describe the exponential increase of transmembrane pressure that typically occurs after the initial stage of an MBR operation...
April 4, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28432933/-non-symbolic-magnitude-processing-in-children-with-mathematical-difficulties-a-meta-analysis
#8
Christin Schwenk, Delphine Sasanguie, Jörg-Tobias Kuhn, Sophia Kempe, Philipp Doebler, Heinz Holling
Symbolic and non-symbolic magnitude representations, measured by digit or dot comparison tasks, are assumed to underlie the development of arithmetic skills. The comparison distance effect (CDE) has been suggested as a hallmark of the preciseness of mental magnitude representations. It implies that two magnitudes are harder to discriminate when the numerical distance between them is small, and may therefore differ in children with mathematical difficulties (MD), i.e., low mathematical achievement or dyscalculia...
April 19, 2017: Research in Developmental Disabilities
https://www.readbyqxmd.com/read/28432906/hydrophobic-and-hydrophilic-properties-of-pollutants-as-a-factor-influencing-their-redistribution-during-snowpack-melt
#9
Krystyna Kozioł, Katarzyna Kozak, Żaneta Polkowska
Glaciers accumulate organic pollutants delivered by snow. However, our understanding of the exact dynamics of organic pollutants in the snowpack relies primarily on laboratory experiments and mathematical models. To fill the gap related to the detailed field data, we have conducted observations of melting snow profiles in two locations and three different stages of melting on one High Arctic glacier, as well as in superimposed ice. We monitored the chemical concentrations of formaldehyde, phenols, short-chain carboxylic acids, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) and snow water equivalents to derive chemical loads...
April 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28432628/design-of-water-quality-monitoring-networks-with-two-information-scenarios-in-tropical-andean-basins
#10
Juan Carlos Bastidas, Jorge Julián Vélez, Jeannette Zambrano, Adela Londoño
Design and redesign of water quality monitoring networks were evaluated for two similarly sized watersheds in the tropical Andes via optimization techniques using geographic information system technology (GIS) and a matter-element analysis of 5-day biological oxygen demand (BOD5) and total suspended solids (TSS). This resulted in a flexible, objectively based design for a 1128-km(2) watershed without prior water quality data (La Miel River), and a network redesign of a 1052-km(2) watershed with historical water quality monitoring (Chinchiná River)...
April 21, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28432579/hcv-cure-and-reinfection-among-people-with-hiv-hcv-coinfection-and-people-who-inject-drugs
#11
REVIEW
Marianne Martinello, Behzad Hajarizadeh, Jason Grebely, Gregory J Dore, Gail V Matthews
PURPOSE OF REVIEW: Highly effective, well-tolerated interferon-free direct-acting antivirals (DAA) have revolutionised hepatitis C virus (HCV) therapeutics, with the opportunity for broad treatment scale-up among marginalised or "high-risk" populations, including people who inject drugs (PWID) and people with HIV/HCV coinfection. RECENT FINDINGS: Concern that HCV reinfection may compromise HCV treatment outcomes is sometimes cited as a reason for not offering treatment to current and former PWID...
April 21, 2017: Current HIV/AIDS Reports
https://www.readbyqxmd.com/read/28432448/resistance-to-radial-expansion-limits-muscle-strain-and-work
#12
E Azizi, A R Deslauriers, N C Holt, C E Eaton
The collagenous extracellular matrix (ECM) of skeletal muscle functions to transmit force, protect sensitive structures, and generate passive tension to resist stretch. The mechanical properties of the ECM change with age, atrophy, and neuromuscular pathologies, resulting in an increase in the relative amount of collagen and an increase in stiffness. Although numerous studies have focused on the effect of muscle fibrosis on passive muscle stiffness, few have examined how these structural changes may compromise contractile performance...
April 21, 2017: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/28432057/imaging-and-modeling-of-acute-pressure-induced-changes-of-collagen-and-elastin-microarchitectures-in-pig-and-human-resistance-arteries
#13
Maria Bloksgaard, Thomas M Leurgans, Bart Spronck, Maarten Hg Heusinkveld, Bjarne Thorsted, Kristoffer Rosenstand, Inger Nissen, Ulla Melchior Hansen, Jonathan R Brewer, Luis A Bagatolli, Lars M Rasmussen, Akhmadjon Irmukhamedov, Koen D Reesink, Jo G R De Mey
The impact of disease related changes in the extracellular matrix (ECM) on the mechanical properties of human resistance arteries largely remains to be established. Resistance arteries from both pig and human parietal pericardium (PRA) display a different ECM microarchitecture compared to frequently used rodent mesenteric arteries. We hypothesized that the biaxial mechanics of PRA mirror pressure induced changes in the ECM microarchitecture. This was tested using isolated pig PRA as model system, integrating vital imaging, pressure myography and mathematical modeling...
April 21, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28431843/on-the-complex-interaction-between-mathematics-and-the-sciences-of-living-systems-comment-on-move-me-astonish-me-delight-my-eyes-and-brain-the-vienna-integrated-model-of-top-down-and-bottom-up-processes-in-art-perception-vimap-and-corresponding-affective-evaluative
#14
https://www.readbyqxmd.com/read/28431573/a-highly-pathogenic-simian-human-immunodeficiency-virus-effectively-produces-infectious-virions-compared-with-a-less-pathogenic-virus-in-cell-culture
#15
Shoya Iwanami, Yusuke Kakizoe, Satoru Morita, Tomoyuki Miura, Shinji Nakaoka, Shingo Iwami
BACKGROUND: The host range of human immunodeficiency virus (HIV) is quite narrow. Therefore, analyzing HIV-1 pathogenesis in vivo has been limited owing to lack of appropriate animal model systems. To overcome this, chimeric simian and human immunodeficiency viruses (SHIVs) that encode HIV-1 Env and are infectious to macaques have been developed and used to investigate the pathogenicity of HIV-1 in vivo. So far, we have many SHIV strains that show different pathogenesis in macaque experiments...
April 21, 2017: Theoretical Biology & Medical Modelling
https://www.readbyqxmd.com/read/28431517/sharp-bounds-on-sufficient-cause-interactions-under-the-assumption-of-no-redundancy
#16
Wen-Chung Lee
BACKGROUND: Sufficient-cause interaction is a type of interaction that has received much attention recently. The sufficient component cause model on which the sufficient-cause interaction is based is however a non-identifiable model. Estimating the interaction parameters from the model is mathematically impossible. METHODS: In this paper, I derive bounding formulae for sufficient-cause interactions under the assumption of no redundancy. RESULTS: Two real data sets are used to demonstrate the method (R codes provided)...
April 21, 2017: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/28431090/current-status-of-the-blue-butterfly-in-fukushima-research
#17
Joji M Otaki, Wataru Taira
Adverse biological impacts of the Fukushima nuclear accident have been revealed using the pale grass blue butterfly, Zizeeria maha, since 2012, which were often considered incompatible with the conventional understanding of radiation biology. This discrepancy likely originates from different system conditions and methodologies. In this article, we first respond to comments from the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) regarding our study; "technical errors" in unit usage and mathematical models noted by UNSCEAR are not errors but reflect our research philosophy not to introduce theoretical assumptions associated with unit conversion and mathematical fit...
April 18, 2017: Journal of Heredity
https://www.readbyqxmd.com/read/28430891/development-and-validation-of-diagnostic-criteria-for-ibd-subtypes-with-an-emphasis-on-ibd-unclassified-in-children-a-multicenter-study-from-the-pediatric-ibd-porto-group-of-espghan
#18
Liron Birimberg-Schwartz, David M Zucker, Amichay Akriv, Salvatore Cucchiara, Fiona L Cameron, David C Wilson, Iza Lazowska, Lambri Yianni, Siba Prosad Paul, Claudio Romano, Sanja Kolacek, Stephan Buderus, Anders Pærregaard, Richard K Russell, Johanna C Escher, Dan Turner
Background: The revised Porto criteria identify subtypes of pediatric inflammatory bowel diseases: ulcerative colitis (UC), atypical UC, Inflammatory Bowel Disease Unclassified (IBDU), and Crohn's disease (CD). In continuation of the Porto criteria, we aimed to derive and validate criteria for standardizing the classification of the IBD subtypes. Methods: This was a multicenter retrospective longitudinal study from 23 centers affiliated with the Porto-group of ESPGHAN...
April 18, 2017: Journal of Crohn's & Colitis
https://www.readbyqxmd.com/read/28430854/dynamic-modeling-and-network-approaches-for-omics-time-course-data-overview-of-computational-approaches-and-applications
#19
Yulan Liang, Arpad Kelemen
Inferring networks and dynamics of genes, proteins, cells and other biological entities from high-throughput biological omics data is a central and challenging issue in computational and systems biology. This is essential for understanding the complexity of human health, disease susceptibility and pathogenesis for Predictive, Preventive, Personalized and Participatory (P4) system and precision medicine. The delineation of the possible interactions of all genes/proteins in a genome/proteome is a task for which conventional experimental techniques are ill suited...
April 18, 2017: Briefings in Bioinformatics
https://www.readbyqxmd.com/read/28430460/subradiance-via-entanglement-in-atoms-with-several-independent-decay-channels
#20
Martin Hebenstreit, Barbara Kraus, Laurin Ostermann, Helmut Ritsch
Spontaneous emission of atoms in free space is modified by the presence of other atoms in close vicinity inducing collective super- and subradiance. For two nearby atoms with a single decay channel the entangled antisymmetric superposition state of the two single excited states will not decay spontaneously. No such excited two-atom dark state exists, if the excited state has two independent optical decay channels of different frequencies or polarizations. However, we show that for an excited atomic state with N-1 independent spontaneous decay channels one can find a highly entangled N-particle dark state, which completely decouples from the vacuum radiation field...
April 7, 2017: Physical Review Letters
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