Read by QxMD icon Read

Grid cells

Jung-Seok Lee, Vijayalaxmi V Mogasale, Vittal Mogasale, Kangsung Lee
BACKGROUND: While the global burden of typhoid fever has been often brought up for attention, the detailed surveillance information has only been available for the limited number of countries. As more efficacious vaccines will be available in the near future, it is essential to understand the geographically diverse patterns of typhoid risk levels and to prioritize the right populations for vaccination to effectively control the disease. METHODS: A composite index called the typhoid risk factor (TRF) index was created based on data with the Global Positioning System (GPS)...
December 5, 2016: BMC Infectious Diseases
Matthias Mörgelin
Negative staining is an essential and versatile staining technique in transmission electron microscopy that can be employed for visualizing bacterial cell morphology, size, and surface architecture at high resolution. Bacteria are usually transferred by passive electrostatic adsorption from suspensions in physiological saline onto suitable hydrophilic support films on electron microscopic grids. There they are contrasted, or "stained," by heavy metal ions in solution such as tungsten, uranyl, molybdate, or vanadate compounds...
2017: Methods in Molecular Biology
Atul Ingle, Tomy Varghese, William Sethares
Percutaneous needle-based liver ablation procedures are becoming increasingly common for treatment of small isolated tumors in hepatocellular carcinoma patients who are not candidates for surgery. Rapid three dimensional visualization of liver ablations has potential clinical value because it can enable interventional radiologists to plan and execute needle-based ablation procedures with real time feedback. Ensuring the right volume of tissue is ablated is desirable to avoid recurrence of tumors from residual untreated cancerous cells...
November 29, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Ali Borji, Mengyang Feng, Huchuan Lu
Several structural scene cues such as gist, layout, horizontal line, openness, and depth have been shown to guide scene perception (e.g., Oliva & Torralba, 2001); Ross & Oliva, 2009). Here, to investigate whether vanishing point (VP) plays a significant role in gaze guidance, we ran two experiments. In the first one, we recorded fixations of 10 observers (six male, four female; mean age 22; SD = 0.84) freely viewing 532 images, out of which 319 had a VP (shuffled presentation; each image for 4 s). We found that the average number of fixations at a local region (80 × 80 pixels) centered at the VP is significantly higher than the average fixations at random locations (t test; n = 319; p < 0...
November 1, 2016: Journal of Vision
M J Loveridge, M J Lain, I D Johnson, A Roberts, S D Beattie, R Dashwood, J A Darr, R Bhagat
Lithium iron phosphate, LiFePO4 (LFP) has demonstrated promising performance as a cathode material in lithium ion batteries (LIBs), by overcoming the rate performance issues from limited electronic conductivity. Nano-sized vanadium-doped LFP (V-LFP) was synthesized using a continuous hydrothermal process using supercritical water as a reagent. The atomic % of dopant determined the particle shape. 5 at. % gave mixed plate and rod-like morphology, showing optimal electrochemical performance and good rate properties vs...
November 29, 2016: Scientific Reports
Evangelos Tsiambas, Christos Riziotis
Cervical cancer screening based on the Papanicolaou (Pap) test is a widely applied but not always efficient practice for detecting Human Papillomavirus (HPV) mediated lesions, partially due to a non-systematic and inadequate screening process. Our aim was to introduce an inexpensive easy-to-use direct screening platform for improved detection of abnormal cells indicative of underlying cervical neoplasia as well as persisting HPV infection. By employing a novel, efficient technique of laser-based micromachining, we achieved the fabrication of spatial grids on commercially available coverslips allowing visual segmentation of the slide for efficient screening...
November 27, 2016: Pathology International
Sarah Baldivia, Alexander Levy, Shylaja Hegde, Stijn J A Aper, Maarten Merkx, Rafael Grytz
Increasing evidence suggests that unknown collagen remodeling mechanisms in the sclera underlie myopia development. We are proposing a novel organ culture system in combination with two-photon fluorescence imaging to quantify collagen remodeling at the tissue- and lamella-level. Tree shrew scleral shells were cultured up to 7 days in serum-free media and cellular viability was investigated under: (i) minimal tissue manipulations; (ii) removal of intraocular tissues; gluing the eye to a washer using (iii) 50 μL and (iv) 200 μL of cyanoacrylate adhesive; (v) supplementing media with Ham's F-12 Nutrient Mixture; and (vi) culturing eyes subjected to 15 mmHg intraocular pressure in our new bioreactor...
2016: PloS One
Oliver Shipston-Sharman, Lukas Solanka, Matthew F Nolan
Neurons in the medial entorhinal cortex encode location through spatial firing fields that have a grid-like organisation. The challenge of identifying mechanisms for grid firing has been addressed through experimental and theoretical investigations of medial entorhinal circuits. Here, we discuss evidence for continuous attractor network models that account for grid firing by synaptic interactions between excitatory and inhibitory cells. These models assume that grid-like firing patterns are the result of computation of location from velocity inputs, with additional spatial input required to oppose drift in the attractor state...
November 15, 2016: Journal of Physiology
Nadya Chakrova, Alicia Soler Canton, Christophe Danelon, Sjoerd Stallinga, Bernd Rieger
Photobleaching is a major factor limiting the observation time in fluorescence microscopy. We achieve photobleaching reduction in structured illumination microscopy (SIM) by locally adjusting the illumination intensities according to the sample. Adaptive SIM is enabled by a digital micro-mirror device (DMD), which provides a projection of the grayscale illumination patterns. We demonstrate a reduction in photobleaching by a factor of three in adaptive SIM compared to the non-adaptive SIM based on a spot grid scanning approach...
October 1, 2016: Biomedical Optics Express
Stefan A Arnold, Stefan Albiez, Andrej Bieri, Anastasia Syntychaki, Ricardo Adaixo, Robb A McLeod, Kenneth N Goldie, Henning Stahlberg, Thomas Braun
We present a sample preparation method for cryo-electron microscopy (cryo-EM) that requires only 3 to 20 nanoliters of sample to prepare a cryo-EM grid, depending on the protocol used. The sample is applied and spread on the grid by a microcapillary. The procedure does not involve any blotting steps, and real-time monitoring allows the water film thickness to be assessed and decreased to an optimum value prior to vitrification. We demonstrate that the method is suitable for high-resolution cryo-EM and will enable alternative electron microscopy approaches, such as single-cell visual proteomics...
November 15, 2016: Journal of Structural Biology
Kees J van Dijk, Marcus L F Janssen, Daphne G M Zwartjes, Yasin Temel, Veerle Visser-Vandewalle, Peter H Veltink, Abdelhamid Benazzouz, Tjitske Heida
Objective: In this study we introduce the use of the current source density (CSD) method as a way to visualize the spatial organization of evoked responses in the rat subthalamic nucleus (STN) at fixed time stamps resulting from motor cortex stimulation. This method offers opportunities to visualize neuronal input and study the relation between the synaptic input and the neural output of neural populations. Approach: Motor cortex evoked local field potentials and unit activity were measured in the subthalamic region, with a 3D measurement grid consisting of 320 measurement points and high spatial resolution...
2016: Frontiers in Neural Circuits
Susanne J Sterbing-D'Angelo, Mohit Chadha, Kara L Marshall, Cynthia F Moss
The wing membrane of the big brown bat (Eptesicus fuscus) is covered by a sparse grid of microscopic hairs. We showed previously that various tactile receptors (e.g. lanceolate endings and Merkel cell neurite complexes) are associated with wing hair follicles. Furthermore, we found that depilation of these hairs decreased the maneuverability of bats in flight. In the present study, we investigated whether somatosensory signals arising from the hairs carry information about air flow parameters. Neural responses to calibrated air puffs on the wing were recorded from primary somatosensory cortex of Eptesicus fuscus...
November 16, 2016: Journal of Neurophysiology
M Rückl, S Rüdiger
Calcium signals in cells occur at multiple spatial scales and variable temporal duration. However, a physical explanation for transitions between long-lasting global oscillations and localized short-term elevations (puffs) of cytoplasmic Ca(2+) is still lacking. Here we introduce a phenomenological, coarse-grained model for the calcium variable, which is represented by ordinary differential equations. Due to its small number of parameters, and its simplicity, this model allows us to numerically study the interplay of multi-scale calcium concentrations with stochastic ion channel gating dynamics even in larger systems...
November 2016: European Physical Journal. E, Soft Matter
Marike Trytsman, Robert H Westfall, Philippus J J Breytenbach, Frikkie J Calitz, Abraham E van Wyk
The principal aim of this study was to establish biogeographical patterns in the legume flora of southern Africa so as to facilitate the selection of species with agricultural potential. Plant collection data from the National Herbarium, South Africa, were analysed to establish the diversity and areas covered by legumes (Leguminosae/Fabaceae) indigenous to South Africa, Lesotho and Swaziland. A total of 27,322 records from 1,619 quarter degree grid cells, representing 1,580 species, 122 genera and 24 tribes were included in the analyses...
2016: PhytoKeys
Qiang Lu, Lei Sheng, Fei Zeng, Shijie Gao, Yanfeng Qiao
Liquid crystal on silicon (LCoS) devices usually show spatial phase nonuniformity (SPNU) in applications of phase modulation, which comprises the phase retardance nonuniformity (PRNU) as a function of the applied voltage and inherent wavefront distortion (WFD) introduced by the device itself. We propose a multipoint calibration method utilizing a Fizeau interferometer to compensate SPNU of the device. Calibration of PRNU is realized by defining a grid of 3×6 cells onto the aperture and then calculating phase retardance of each cell versus a gradient gray pattern...
October 1, 2016: Applied Optics
Céline Cozic, Fabien Audran, Christophe Blanchard, Christophe David, Vincent Andre, Michel Caulier, Stéphane Varin, Gilles Tanguy, Jérôme Dimet, Grégoire Cormier
OBJECTIVES: To decrease radiation exposure of patients undergoing interventional rheumatology procedures, without adversely affecting quality of care. METHODS: The radiation dose received, assessed by the dose-area product (DAP), was measured during 283 intraarticular injections performed under fluoroscopic guidance between May and July 2013. Then, three steps were taken to decrease patients' radiation exposure: a copper filter was added, the anti-scatter grid was removed, and exposure cell sensitivity was set at the highest value...
November 4, 2016: Joint, Bone, Spine: Revue du Rhumatisme
Grant E Johnson, Trevor Moser, Mark Engelhard, Nigel D Browning, Julia Laskin
About 40 years ago, it was shown that tungsten carbide exhibits similar catalytic behavior to Pt for certain commercially relevant reactions, thereby suggesting the possibility of cheaper and earth-abundant substitutes for costly and rare precious metal catalysts. In this work, reactive magnetron sputtering of Ta in the presence of three model hydrocarbons (2-butanol, heptane, and m-xylene) combined with gas aggregation and ion soft landing was employed to prepare organic-inorganic hybrid nanoparticles (NPs) on surfaces for evaluation of catalytic activity and durability...
November 7, 2016: Journal of Chemical Physics
Camille Françoise Peitsch, Sven Beckmann, Benoît Zuber
The plasma membrane and the cell cortex are essential parts of the eukaryotic cell. The plasma membrane delimitates the cell and mediates communication with the outside. The cell cortex is the submembrane cytoskeleton shaping the cell and is able to reorganize for the passage of material. To study events at and near the plasma membrane, cryoelectron microscopy (cryo-EM) may be used. Most intact cells are too thick for direct cryo-EM imaging. Generating cell-free membrane patches could be a means to study features at the plasma membrane...
October 31, 2016: Structure
Jason L Chien, Mark P Ghassibi, Thipnapa Patthanathamrongkasem, Ramiz Abumasmah, Michael S Rosman, Alon Skaat, Celso Tello, Jeffrey M Liebmann, Robert Ritch, Sung Chul Park
PURPOSE: To compare glaucoma diagnostic capability of global/regional macular layer parameters in different-sized grids. MATERIALS AND METHODS: Serial horizontal spectral-domain optical coherence tomography scans of macula were obtained. Automated macular grids with diameters of 3, 3.45, and 6 mm were used. For each grid, 10 parameters (total volume; average thicknesses in 9 regions) were obtained for 5 layers: macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), ganglion cell-inner plexiform layer (GCIPL; GCL+IPL), and ganglion cell complex (GCC; mRNFL+GCL+IPL)...
November 2, 2016: Journal of Glaucoma
Jaker Hossain, Qiming Liu, Takuya Miura, Koji Kasahara, Daisuke Harada, Ryo Ishikawa, Keiji Ueno, Hajime Shirai
We demonstrate the chemistry of amphiphilic perfluorosulfonic copolymer Nafion-coated conductive poly(3,4-ethyelenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and its effect on the photovoltaic performance of PEDOT:PSS/crystalline Si (c-Si) heterojunction solar cells. The highly hydrophilic sulfonate group of insulating, chemically stable Nafion interacts with PSS in PEDOT:PSS, which reduce the coulombic interaction between PEDOT and PSS. The highly hydrophobic fluorocarbon backbone of Nafion favorably interacts with hydrophobic PEDOT of PEDOT:PSS...
November 3, 2016: ACS Applied Materials & Interfaces
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"