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https://www.readbyqxmd.com/read/28211677/super-resolution-microscopy-shedding-light-on-the-cellular-plasma-membrane
#1
Matthew B Stone, Sarah A Shelby, Sarah L Veatch
Lipids and the membranes they form are fundamental building blocks of cellular life, and their geometry and chemical properties distinguish membranes from other cellular environments. Collective processes occurring within membranes strongly impact cellular behavior and biochemistry, and understanding these processes presents unique challenges due to the often complex and myriad interactions between membrane components. Super-resolution microscopy offers a significant gain in resolution over traditional optical microscopy, enabling the localization of individual molecules even in densely labeled samples and in cellular and tissue environments...
February 17, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28211479/decoupling-absorption-and-emission-processes-in-super-resolution-localization-of-emitters-in-a-plasmonic-hotspot
#2
David L Mack, Emiliano Cortés, Vincenzo Giannini, Peter Török, Tyler Roschuk, Stefan A Maier
The absorption process of an emitter close to a plasmonic antenna is enhanced due to strong local electromagnetic (EM) fields. The emission, if resonant with the plasmonic system, re-radiates to the far-field by coupling with the antenna via plasmonic states, whose presence increases the local density of states. Far-field collection of the emission of single molecules close to plasmonic antennas, therefore, provides mixed information of both the local EM field strength and the local density of states. Moreover, super-resolution localizations from these emission-coupled events do not report the real position of the molecules...
February 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28208837/projections-onto-convex-sets-super-resolution-reconstruction-based-on-point-spread-function-estimation-of-low-resolution-remote-sensing-images
#3
Chong Fan, Chaoyun Wu, Grand Li, Jun Ma
To solve the problem on inaccuracy when estimating the point spread function (PSF) of the ideal original image in traditional projection onto convex set (POCS) super-resolution (SR) reconstruction, this paper presents an improved POCS SR algorithm based on PSF estimation of low-resolution (LR) remote sensing images. The proposed algorithm can improve the spatial resolution of the image and benefit agricultural crop visual interpolation. The PSF of the highresolution (HR) image is unknown in reality. Therefore, analysis of the relationship between the PSF of the HR image and the PSF of the LR image is important to estimate the PSF of the HR image by using multiple LR images...
February 13, 2017: Sensors
https://www.readbyqxmd.com/read/28206746/direct-formation-of-large-area-2d-nanosheets-from-fluorescent-semiconducting-homopolymer-with-orthorhombic-crystalline-orientation
#4
Sanghee Yang, Suyong Shin, Inho Choi, Jaeho Lee, Tae-Lim Choi
Semiconducting polymers have been widely investigated due to their intriguing optoelectronic properties and their high crystallinity that provides a strong driving force for self-assembly. Although there are various reports of successful self-assembly of nanostructures using semiconducting polymers, direct in situ self-assembly of these polymers into two-dimensional (2D) nanostructures has proven difficult, despite their importance for optoelectronics applications. Here, we report the synthesis of a simple conjugated homopolymer by living cyclopolymerization of a 1,6-heptadiyne (having a fluorene moiety) and its efficient in situ formation of large-area 2D fluorescent semiconducting nanostructures...
February 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28202688/super-resolution-mapping-of-scaffold-nucleoporins-in-the-nuclear-pore-complex
#5
Jiong Ma, Joseph M Kelich, Samuel L Junod, Weidong Yang
The nuclear pore complex (NPC), composed of ∼30 different nucleoporins (Nups), is one of the largest supramolecular structures in eukaryotic cells. Its octagonal ring-scaffold perforates the nuclear envelope and features a unique molecular machinery that regulates nucleocytoplasmic transport. However, the precise copy number and the spatial location of each Nup in the native NPC remain obscure due to the inherent difficulty of counting and localizing proteins inside the sub-micrometer supramolecular complex...
February 15, 2017: Journal of Cell Science
https://www.readbyqxmd.com/read/28198852/influence-of-the-background-medium-on-imaging-performance-of-microsphere-assisted-super-resolution-microscopy
#6
Arash Darafsheh
We demonstrated the importance of the refractive index of the background medium containing the microsphere in microsphere-assisted super-resolution microscopy. We performed numerical simulation and showed that the photonic nanojet properties of a microlens can be optimized by adjusting the index of the background medium surrounding it. Our simulation results, in qualitative agreement with experimental observations, demonstrated that for the same refractive index contrast between the microsphere and its surrounding medium, a high-index microsphere embedded in a medium provides sharper focusing and better imaging quality compared with its low-index counterpart working in air...
February 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28197066/patch-based-super-resolution-of-mr-spectroscopic-images-application-to-multiple-sclerosis
#7
Saurabh Jain, Diana M Sima, Faezeh Sanaei Nezhad, Gilbert Hangel, Wolfgang Bogner, Stephen Williams, Sabine Van Huffel, Frederik Maes, Dirk Smeets
Purpose: Magnetic resonance spectroscopic imaging (MRSI) provides complementary information to conventional magnetic resonance imaging. Acquiring high resolution MRSI is time consuming and requires complex reconstruction techniques. Methods: In this paper, a patch-based super-resolution method is presented to increase the spatial resolution of metabolite maps computed from MRSI. The proposed method uses high resolution anatomical MR images (T1-weighted and Fluid-attenuated inversion recovery) to regularize the super-resolution process...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28196307/molecule-counts-in-localization-microscopy-with-organic-fluorophores
#8
Mike Heilemann, Franziska Fricke, Christos Karathanasis, Gerhard Hummer
Single-molecule localization microscopy (SMLM) can be used to count fluorescently labeled molecules even when they are not individually resolved. We demonstrate SMLM molecule counting for nucleic acids labeled with the organic fluorophore Alexa Fluor 647 and imaged under photoswitching conditions. From the observed distributions of the number of fluorophore blinking events, we extracted the number of fluorophores per spot using a statistical model. We validate the molecule counting method for single Alexa Fluor 647 fluorophores, and for trimers of Alexa Fluor 647 constructed on a DNA origami structure...
February 14, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28195833/a-generalized-framework-unifying-image-registration-and-respiratory-motion-models-and-incorporating-image-reconstruction-for-partial-image-data-or-full-images
#9
Jamie R McClelland, Marc Modat, Simon Arridge, Helen Grimes, Derek D'Souza, David Thomas, Dylan O'Connell, Daniel Low, Evangelia Kaza, David Collins, Martin Leach, David Hawkes
Surrogate-driven respiratory motion models relate the motion of the internal anatomy to easily acquired respiratory surrogate signals, such as the motion of the skin surface. They are usually built by first using image registration to determine the motion from a number of dynamic images, and then fitting a correspondence model relating the motion to the surrogate signals. In this paper we present a generalized framework that unifies the image registration and correspondence model fitting into a single optimization...
February 14, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28194645/expression-of-a-novel-ciliary-protein-iiig9-during-the-differentiation-and-maturation-of-ependymal-cells
#10
M Cifuentes, V Baeza, P M Arrabal, R Visser, J M Grondona, N Saldivia, F Martínez, F Nualart, K Salazar
IIIG9 is the regulatory subunit 32 of protein phosphatase 1 (PPP1R32), a key phosphatase in the regulation of ciliary movement. IIIG9 localization is restricted to cilia in the trachea, fallopian tube, and testicle, suggesting its involvement in the polarization of ciliary epithelium. In the adult brain, IIIG9 mRNA has only been detected in ciliated ependymal cells that cover the ventricular walls. In this work, we prepared a polyclonal antibody against rat IIIG9 and used this antibody to show for the first time the ciliary localization of this protein in adult ependymal cells...
February 13, 2017: Molecular Neurobiology
https://www.readbyqxmd.com/read/28192299/single-molecule-analysis-of-fluorescent-carbon-dots-towards-localization-based-super-resolution-microscopy
#11
Navneet C Verma, Syamantak Khan, Chayan K Nandi
The advancement of high-resolution bioimaging has always been dependent on the discovery of bright and easily available fluorescent probes. Fluorescent carbon nanodots, an interesting class of relatively new nanomaterials, have emerged as a versatile alternative due to their superior optical properties, non-toxicity, cell penetrability and easy routes to synthesis. Although a plethora of reports is available on bioimaging using carbon dots, single-molecule-based super-resolution imaging is rare in the literature...
October 11, 2016: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28186887/accelerated-singular-value-based-ultrasound-blood-flow-clutter-filtering-with-randomized-singular-value-decomposition-rsvd-and-randomized-spatial-downsampling
#12
Pengfei Song, Joshua Trzasko, Armando Manduca, Bo Qiang, Ramanathan Kadirvel, David Kallmes, Shigao Chen
Singular value decomposition (SVD)-based ultrasound blood flow clutter filters have recently demonstrated substantial improvement in clutter rejection for ultrafast plane wave microvessel imaging, and have become the commonly used clutter filtering method for many novel ultrafast imaging applications such as functional ultrasound and super-resolution imaging. At present, however, the computational burden of SVD remains as a major hurdle for practical implementation and clinical translation of this method. To address this challenge, in the study we present two blood flow clutter filtering methods based on randomized singular value decomposition (rSVD) and randomized spatial downsampling to accelerate SVD clutter filtering with minimal compromise to the clutter filter performance...
February 7, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28185951/evaluation-of-slice-dithered-enhanced-resolution-simultaneous-multislice-slider-sms-for-human-fmri
#13
An T Vu, Alex Beckett, Kawin Setsompop, David A Feinberg
High isotropic resolution fMRI is challenging primarily due to long repetition times (TR) and insufficient SNR, especially at lower field strengths. Recently, Simultaneous Multi-Slice (SMS) imaging with blipped-CAIPI has substantially reduced scan time and improved SNR efficiency of fMRI. Similarly, super-resolution techniques utilizing sub- voxel spatial shifts in the slice direction have increased both resolution and SNR efficiency. Here we demonstrate the synergistic combination of SLIce Dithered Enhanced Resolution (SLIDER) and SMS for high-resolution, high-SNR whole brain fMRI in comparison to standard resolution fMRI data as well as high-resolution data...
February 6, 2017: NeuroImage
https://www.readbyqxmd.com/read/28182553/multi-dimensional-sparse-models
#14
Na Qi, Yunhui Shi, Xiaoyan Sun, Jingdong Wang, Baocai Yin, Junbin Gao
Traditional synthesis/analysis sparse representation models signals in a one dimensional (1D) way, in which a multidimensional (MD) signal is converted into a 1D vector. 1D modeling cannot sufficiently handle MD signals of high dimensionality in limited computational resources and memory usage, as breaking the data structure and inherently ignores the diversity of MD signals (tensors). We utilize the multilinearity of tensors to establish the redundant basis of the space of multi linear maps with the sparsity constraint, and further propose MD synthesis/analysis sparse models to effectively and efficiently represent MD signals in their original form...
February 2, 2017: IEEE Transactions on Pattern Analysis and Machine Intelligence
https://www.readbyqxmd.com/read/28181372/resolution-and-super-resolution
#15
REVIEW
Colin J R Sheppard
Many papers have claimed the attainment of super-resolution, i.e. resolution beyond that achieved classically, by measurement of the profile of a feature in the image. We argue that measurement of the contrast of the image of a dark bar on a bright background does not give a measure of resolution, but of detection sensitivity. The width of a bar that gives an intensity at the center of the bar of 0.735 that in the bright region (the same ratio as in the Rayleigh resolution criterion) is λ/(13.9×numerical aperture) for the coherent case with central illumination...
February 9, 2017: Microscopy Research and Technique
https://www.readbyqxmd.com/read/28181027/track-weighted-imaging-methods-extracting-information-from-a-streamlines-tractogram
#16
REVIEW
Fernando Calamante
A whole-brain streamlines data-set (so-called tractogram) generated from diffusion MRI provides a wealth of information regarding structural connectivity in the brain. Besides visualisation strategies, a number of post-processing approaches have been proposed to extract more detailed information from the tractogram. One such approach is based on exploiting the information contained in the tractogram to generate track-weighted (TW) images. In the track-weighted imaging (TWI) approach, a very large number of streamlines are often generated throughout the brain, and an image is then computed based on properties of the streamlines themselves (e...
February 8, 2017: Magma
https://www.readbyqxmd.com/read/28180219/super-resolution-imaging-of-alpha-synuclein-polymorphisms-and-their-potential-role-in-neurodegeneration
#17
REVIEW
Eileen Nugent, Clemens F Kaminski, Gabriele S Kaminski Schierle
The conversion of soluble, functional proteins into amyloid fibrils has been linked to the development of neurodegenerative disorders, including Parkinson's and Alzheimer's disease. In the brains of patients with these disorders, the increasing presence of amyloid-containing plaques corresponds to neuronal cell death and the worsening of symptoms. However, protein amyloids are not merely confined to dying cells. Rather, some show a propensity to be transmitted to, and enter adjacent cells and induce the polymerization of the native monomer population...
February 9, 2017: Integrative Biology: Quantitative Biosciences From Nano to Macro
https://www.readbyqxmd.com/read/28178815/unfolding-dna-condensates-produced-by-dna-like-charged-depletants-a-force-spectroscopy-study
#18
C H M Lima, M S Rocha, E B Ramos
In this work, we have measured, by means of optical tweezers, forces acting on depletion-induced DNA condensates due to the presence of the DNA-like charged protein bovine serum albumin (BSA). The stretching and unfolding measurements performed on the semi-flexible DNA chain reveal (1) the softening of the uncondensed DNA contour length and (2) a mechanical behavior strikingly different from those previously observed: the force-extension curves of BSA-induced DNA condensates lack the "saw-tooth" pattern and applied external forces as high as ≈80 pN are unable to fully unfold the condensed DNA contour length...
February 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28178524/astrocytes-resist-hiv-1-fusion-but-engulf-infected-macrophage-material
#19
Rebecca A Russell, Jakub Chojnacki, Daniel M Jones, Errin Johnson, Thao Do, Christian Eggeling, Sergi Padilla-Parra, Quentin J Sattentau
HIV-1 disseminates to diverse tissues and establishes long-lived viral reservoirs. These reservoirs include the CNS, in which macrophage-lineage cells, and as suggested by many studies, astrocytes, may be infected. Here, we have investigated astrocyte infection by HIV-1. We confirm that astrocytes trap and internalize HIV-1 particles for subsequent release but find no evidence that these particles infect the cell. Astrocyte infection was not observed by cell-free or cell-to-cell routes using diverse approaches, including luciferase and GFP reporter viruses, fixed and live-cell fusion assays, multispectral flow cytometry, and super-resolution imaging...
February 7, 2017: Cell Reports
https://www.readbyqxmd.com/read/28177548/7t-guided-super-resolution-of-3t-mri
#20
Khosro Bahrami, Feng Shi, Islem Rekik, Yaozong Gao, Dinggang Shen
PURPOSE: High-resolution MR images can depict rich details of brain anatomical structures and show subtle changes in longitudinal data. 7T MRI scanners can acquire MR images with higher resolution and better tissue contrast than the routine 3T MRI scanners. However, 7T MRI scanners are currently more expensive and less available in clinical and research centers. To this end, we propose a method to generate super-resolution 3T MRI that resembles 7T MRI, which is called as 7T-like MR image in this paper...
February 8, 2017: Medical Physics
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