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Spatial dependence analysis

Ebrahim Aboualizadeh, Christine M Sorenson, Alex J Schofield, Miriam Unger, Nader Sheibani, Carol J Hirschmugl
To discover the mechanisms underlying the progression of diabetic retinopathy (DR), a more comprehensive understanding of the biomolecular processes in individual retinal cells subjected to hyperglycemia is required. Despite extensive studies, the changes in the biochemistry of retinal layers during the development of DR are not well known. In this study, we aimed to determine a more detailed understanding of the natural history of DR in Akita/+ (type 1 diabetes model) male mice with different duration of diabetes...
January 18, 2018: Scientific Reports
Jakob Neef, Nicolai T Urban, Tzu-Lun Ohn, Thomas Frank, Philippe Jean, Stefan W Hell, Katrin I Willig, Tobias Moser
Ca2+ influx triggers the release of synaptic vesicles at the presynaptic active zone (AZ). A quantitative characterization of presynaptic Ca2+ signaling is critical for understanding synaptic transmission. However, this has remained challenging to establish at the required resolution. Here, we employ confocal and stimulated emission depletion (STED) microscopy to quantify the number (20-330) and arrangement (mostly linear 70 nm × 100-600 nm clusters) of Ca2+ channels at AZs of mouse cochlear inner hair cells (IHCs)...
January 18, 2018: Nature Communications
I Cortés-Domínguez, J Burguete
We present the experimental analysis of the instabilities generated on a large drop of liquid metal by a time-dependent magnetic field. The study is done exploring the range of tiny values of the control parameter (the ratio between the Lorentz forces and inertia) avoiding nonlinear effects. Two different instabilities break the symmetries generating spatial patterns that appear without a threshold for some specific frequencies (up to the experimental precision) and have been observed for parameter values two orders of magnitude lower than in previously published experiments [J...
July 2017: Physical Review. E
Natasha C Gabay, P A Robinson
Perturbation analysis of neural field theory is used to derive eigenmodes of neural activity on a cortical hemisphere, which have previously been calculated numerically and found to be close analogs of spherical harmonics, despite heavy cortical folding. The present perturbation method treats cortical folding as a first-order perturbation from a spherical geometry. The first nine spatial eigenmodes on a population-averaged cortical hemisphere are derived and compared with previous numerical solutions. These eigenmodes contribute most to brain activity patterns such as those seen in electroencephalography and functional magnetic resonance imaging...
September 2017: Physical Review. E
Nitzan Razin, Raphael Voituriez, Jens Elgeti, Nir S Gov
We show how a gradient in the motility properties of noninteracting pointlike active particles can cause a pressure gradient that pushes a large inert object. We calculate the force on an object inside a system of active particles with position-dependent motion parameters, in one and two dimensions, and show that a modified Archimedes' principle is satisfied. We characterize the system, both in terms of the model parameters and in terms of experimentally measurable quantities: the spatial profiles of the density, velocity and pressure...
September 2017: Physical Review. E
Murat Alp, Francis A Cucinotta
Exposure to heavy-ion radiation during cancer treatment or space travel may cause cognitive detriments that have been associated with changes in neuron morphology and plasticity. Observations in mice of reduced neuronal dendritic complexity have revealed a dependence on radiation quality and absorbed dose, suggesting that microscopic energy deposition plays an important role. In this work we used morphological data for mouse dentate granular cell layer (GCL) neurons and a stochastic model of particle track structure and microscopic energy deposition (ED) to develop a predictive model of high-charge and energy (HZE) particle-induced morphological changes to the complex structures of dendritic arbors...
January 18, 2018: Radiation Research
Amicie de Pierrefeu, Thomas Fovet, Fouad Hadj-Selem, Tommy Löfstedt, Philippe Ciuciu, Stephanie Lefebvre, Pierre Thomas, Renaud Lopes, Renaud Jardri, Edouard Duchesnay
Despite significant progress in the field, the detection of fMRI signal changes during hallucinatory events remains difficult and time-consuming. This article first proposes a machine-learning algorithm to automatically identify resting-state fMRI periods that precede hallucinations versus periods that do not. When applied to whole-brain fMRI data, state-of-the-art classification methods, such as support vector machines (SVM), yield dense solutions that are difficult to interpret. We proposed to extend the existing sparse classification methods by taking the spatial structure of brain images into account with structured sparsity using the total variation penalty...
January 16, 2018: Human Brain Mapping
Jintao Sheng, Yuedi Shen, Yanhua Qin, Lei Zhang, Binjia Jiang, Yaoyao Li, Luoyi Xu, Wei Chen, Jinhui Wang
Although imbalanced functional integration has been increasingly reported in major depressive disorder (MDD), there still lacks a general framework to characterize common characteristic and origin shared by the integrative disturbances. Here we examined spatial selectivity, temporal uniqueness, metabolic basis, and therapeutic response of altered functional connectivity (FC) in MDD by analyzing both cross-sectional and longitudinal multimodal functional magnetic resonance imaging data from 35 patients and 34 demographically matched healthy controls...
January 17, 2018: Human Brain Mapping
Francois M Moukam Kakmeni, Ritter Y A Guimapi, Frank T Ndjomatchoua, Sansoa A Pedro, James Mutunga, Henri E Z Tonnang
BACKGROUND: Malaria is highly sensitive to climatic variables and is strongly influenced by the presence of vectors in a region that further contribute to parasite development and sustained disease transmission. Mathematical analysis of malaria transmission through the use and application of the value of the basic reproduction number (R0) threshold is an important and useful tool for the understanding of disease patterns. METHODS: Temperature dependence aspect of R0 obtained from dynamical mathematical network model was used to derive the spatial distribution maps for malaria transmission under different climatic and intervention scenarios...
January 16, 2018: International Journal of Health Geographics
Otto Scheibelhofer, Patrick R Wahl, Boris Larchevêque, Fabien Chauchard, Johannes G Khinast
Understanding the behavior of light in granular media is necessary for determining the sample size, shape, and weight when probing using fiber optic setups. This is required for a correct estimate of the active pharmaceutical ingredient content in a pharmaceutical blend via near-infrared spectroscopy. Several strategies to describe the behavior of light in granular and turbid media exist. A common approach is the Monte-Carlo simulation of individual photons and their description using mean free path lengths for scattering and absorption...
January 1, 2018: Applied Spectroscopy
G A McAuliffe, T Takahashi, R J Orr, P Harris, M R F Lee
Life Cycle Assessment (LCA) of livestock production systems is often based on inventory data for farms typical of a study region. As information on individual animals is often unavailable, livestock data may already be aggregated at the time of inventory analysis, both across individual animals and across seasons. Even though various computational tools exist to consider the effect of genetic and seasonal variabilities in livestock-originated emissions intensity, the degree to which these methods can address the bias suffered by representative animal approaches is not well-understood...
January 10, 2018: Journal of Cleaner Production
Trevor D S Bloom, Aquila Flower, Eric G DeChaine
Species Distribution Models (SDMs) are widely used to understand environmental controls on species' ranges and to forecast species range shifts in response to climatic changes. The quality of input data is crucial determinant of the model's accuracy. While museum records can be useful sources of presence data for many species, they do not always include accurate geographic coordinates. Therefore, actual locations must be verified through the process of georeferencing. We present a practical, standardized manual georeferencing method (the Spatial Analysis Georeferencing Accuracy (SAGA) protocol) to classify the spatial resolution of museum records specifically for building improved SDMs...
January 2018: Ecology and Evolution
Francesco Sessa, Valentina Migliorati, Alessandra Serva, Andrea Lapi, Giuliana Aquilanti, Giordano Mancini, Paola D'Angelo
A synergic approach combining molecular dynamics (MD) simulations and X-ray absorption spectroscopy has been used to investigate diluted solutions of zinc bis(trifluoromethanesulfonyl)imide (Zn(Tf2N)2) in Tf2N- based ionic liquids (ILs) having different organic cations, namely the 1-butyl-3-methylimidazolium ([C4(mim)]+), 1,8-bis(3-methylimidazolium-1-yl)octane ([C8(mim)2]2+), N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium ([Choline]+) and butyltrimethylammonium ([BTMA]+) ions. All of the ILs tend to dissolve the Zn(Tf2N)2 species giving rise to a different structural arrangement around the Zn2+ as compared to that of the salt crystallographic structure...
January 10, 2018: Physical Chemistry Chemical Physics: PCCP
Markus M Knodel, Arne Nägel, Sebastian Reiter, Andreas Vogel, Paul Targett-Adams, John McLauchlan, Eva Herrmann, Gabriel Wittum
Exploring biophysical properties of virus-encoded components and their requirement for virus replication is an exciting new area of interdisciplinary virological research. To date, spatial resolution has only rarely been analyzed in computational/biophysical descriptions of virus replication dynamics. However, it is widely acknowledged that intracellular spatial dependence is a crucial component of virus life cycles. The hepatitis C virus-encoded NS5A protein is an endoplasmatic reticulum (ER)-anchored viral protein and an essential component of the virus replication machinery...
January 8, 2018: Viruses
Merle C Hoenig, Gérard N Bischof, Joseph Seemiller, Jochen Hammes, Juraj Kukolja, Özgür A Onur, Frank Jessen, Klaus Fliessbach, Bernd Neumaier, Gereon R Fink, Thilo van Eimeren, Alexander Drzezga
A stereotypical anatomical propagation of tau pathology has been described in Alzheimer's disease. According to recent concepts (network degeneration hypothesis), this propagation is thought to be indicative of misfolded tau proteins possibly spreading along functional networks. If true, tau pathology accumulation should correlate in functionally connected brain regions. Therefore, we examined whether independent components could be identified in the distribution pattern of in vivo tau pathology and whether these components correspond with specific functional connectivity networks...
January 5, 2018: Brain: a Journal of Neurology
Julio de Pablos, Lucas Arbeloa-Gutierrez, Antonio Arenas-Miquelez
PURPOSE OF REVIEW: Treatments available to correct adolescent Blount disease deformities differ in terms of features, advantages, and disadvantages. Each is indicated, therefore, for different scenarios of severity, physeal condition, and maturity. The purpose of this review is to update basic concepts, surgical treatments, and controversies concerning this disorder. RECENT FINDINGS: The cause of Blount disease is unknown although etiologic factors as morbid obesity and hypovitaminosis D are thought to be associated with it...
February 2018: Current Opinion in Pediatrics
Rustem R Amirov, Julia Shayimova, Zarina Nasirova, Alexander Solodov, Ayrat M Dimiev
The sorption capacity of graphene oxide (GO) toward different metal cations has been the subject of several recent studies. However, the reported quantitative data are controversial, and the mechanism of chemical bonding between GO and metal cations is poorly understood. Clarifying these questions can eventually help to reveal the fine chemical structure of GO that remains ambiguous. In this work, we study the binding of Gd3+ and Mn2+ by GO in the presence of several competing metal cations by the 1H NMR relaxation method...
January 5, 2018: Physical Chemistry Chemical Physics: PCCP
Oleksandr I Malyi, Kostiantyn V Sopiha, Ihor Radchenko, Ping Wu, Clas Persson
Controlling the thickness dependence of electronic properties for two-dimensional (2d) materials is among the primary goals for their large-scale applications. Herein, employing a first-principles computational approach, we predict that Si interaction with multilayer phosphorene (2d-P) can result in the formation of highly stable 2d-SiP and 2d-SiP2 compounds with a weak interlayer interaction. Our analysis demonstrates that these systems are semiconductors with band gap energies that can be governed by varying the thicknesses and stacking arrangements...
January 5, 2018: Physical Chemistry Chemical Physics: PCCP
Jaideep Dutta, Balaram Kundu
This research article determines an exact analytical expression for 2-D thermal field in single layer living tissues under a therapeutic condition by means of Fourier and non-Fourier heat transfer approaches. An actual spatially dependent initial condition has been adopted to analyze the heat propagation in tissues. The exact analytical determination for this actual initial condition for temperature may be difficult. However, in this study, an approximate analytical method has newly been established for an appropriate initial condition...
January 2018: Journal of Thermal Biology
M E Jácome-Flores, Miguel Delibes, Thorsten Wiegand, José M Fedriani
Background and Aims: Nursery pollination is a highly specialized interaction in which pollinators breed inside plant reproductive structures. Pollinator occupancy of host plants often depends on plant location, flowering synchrony and sex. The nursery pollination system between the dioecious dwarf palm Chamaerops humilis (Arecaceae) and the host-specific palm flower weevil Derelomus chamaeropsis was investigated. For the first time, sex, flowering synchrony and spatial distribution of plants was related to the occupancy probability and the abundance of D...
January 2, 2018: Annals of Botany
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