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particle tracking

Pia Pužar Dominkuš, Matjaž Stenovec, Simona Sitar, Eva Lasič, Robert Zorec, Ana Plemenitaš, Ema Žagar, Marko Kreft, Metka Lenassi
PKH lipophilic dyes are highly fluorescent and stain membranes by intercalating their aliphatic portion into the exposed lipid bilayer. They have established use in labeling and tracking of cells in vivo and in vitro. Despite wide use of PKH-labeled extracellular vesicles (EVs) in cell targeting and functional studies, nonEV-associated fluorescent structures have never been examined systematically, nor was their internalization by cells. Here, we have characterized PKH26-positive particles in lymphoblastoid B exosome samples and exosome-free controls stained by ultracentrifugation, filtration, and sucrose-cushion-based and sucrose-gradient-based procedures, using confocal imaging and asymmetric-flow field-flow fractionation coupled to multi-angle light-scattering detector analysis...
March 15, 2018: Biochimica et Biophysica Acta
Diego Averaldo Guiguet Leal, Doris Sobral Marques Souza, Karin Silva Caumo, Gislaine Fongaro, Lua Ferreira Panatieri, Maurício Durigan, Marilise Brittes Rott, Célia Regina Monte Barardi, Regina Maura Bueno Franco
Waterborne, food-borne and sewage-borne pathogens are a major global concern, with the annual recurrence, most notably during the summer, of outbreaks of gastroenteritis of unconfirmed etiology associated with recreational activities in marine environments. The consumption of contaminated water-based foodstuffs is also related to outbreaks of human illness. The main goals of the present study were: i) to identify the genetic assemblages of Giardia duodenalis cysts in growing and depurated oysters destined for human consumption on the southern coast of São Paulo, Brazil; ii) to verify the main circulating G...
March 9, 2018: Water Research
Alvaro Marin, Henri Lhuissier, Massimiliano Rossi, Christian J Kähler
The flow of a charged-stabilized suspension through a single constricted channel is studied experimentally by tracking the particles individually. Surprisingly, the behavior is found to be qualitatively similar to that of inertial dry granular systems: For small values of the neck-to-particle size ratio (D/d<3), clogs form randomly as arches of the particle span the constriction. The statistics of the clogging events are Poissonian as reported for granular systems and agree for moderate particle volume fraction (ϕ≈20%) with a simple stochastic model for the number of particles at the neck...
February 2018: Physical Review. E
Henrik Lauridsen, Casper Bindzus Foldager, Line Hansen, Michael Pedersen
Non-invasive methods to track the progress of stem cell therapies are important in the development of future regenerative therapies. Super-paramagnetic iron oxide particles (SPIOs) have previously been applied to track cells using magnetic resonance imaging (MRI) in vivo in non-regenerative animal models. To the best of the author's knowledge, the present study investigated for the first time, the feasibility of tracking SPIO labeled cells in an intrinsic regenerative environment, the regenerating limb of the axolotl, and investigated the homing of stem cell-like blastema cells to the regenerative zone...
April 2018: Experimental and Therapeutic Medicine
Lisa K Gouwens, Mudar S Ismail, Victoria A Rogers, Nathan T Zeller, Evan C Garrad, Fatima S Amtashar, Nyasha J Makoni, David C Osborn, Michael R Nichols
Microvesicles (MVs) and exosomes comprise a class of cell-secreted particles termed extracellular vesicles (EVs). These cargo-holding vesicles mediate cell-to-cell communication and have recently been implicated in neurodegenerative diseases such as Alzheimer's disease (AD). The two types of EVs are distinguished by the mechanism of cell release and their size, with the smaller exosomes and the larger MVs ranging from 30 to 100 nm and 100 nm to 1 μm in diameter, respectively. MV numbers are increased in AD and appear to interact with amyloid-β peptide (Aβ), the primary protein component of the neuritic plaques in the AD brain...
March 15, 2018: ACS Chemical Neuroscience
Tianzhu Zhang, Si Liu, Changsheng Xu, Bin Liu, Ming-Hsuan Yang
In this paper, we propose a novel correlation particle filter (CPF) for robust visual tracking. Instead of a simple combination of a correlation filter and a particle filter, we exploit and complement the strength of each one. Compared with existing tracking methods based on correlation filters and particle filters, the proposed tracker has four major advantages: 1) it is robust to partial and total occlusions, and can recover from lost tracks by maintaining multiple hypotheses; 2) it can effectively handle large-scale variation via a particle sampling strategy; 3) it can efficiently maintain multiple modes in the posterior density using fewer particles than conventional particle filters, resulting in low computational cost; and 4) it can shepherd the sampled particles toward the modes of the target state distribution using a mixture of correlation filters, resulting in robust tracking performance...
June 2018: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
M Di Liberto, A Recati, N Trivedi, I Carusotto, C Menotti
We study the low-energy excitations of the Bose-Hubbard model in the strongly interacting superfluid phase using a Gutzwiller approach. We extract the single-particle and single-hole excitation amplitudes for each mode and report emergent mode-dependent particle-hole symmetry on specific arc-shaped lines in the phase diagram connecting the well-known Lorentz-invariant limits of the Bose-Hubbard model. By tracking the in-phase particle-hole symmetric oscillations of the order parameter, we provide an answer to the long-standing question about the fate of the pure amplitude Higgs mode away from the integer-density critical point...
February 16, 2018: Physical Review Letters
Paul M Barlow, Stanley A Leake, Michael N Fienen
The term capture, related to the source of water derived from wells, has been used in two distinct yet related contexts by the hydrologic community. The first is a water-budget context, in which capture refers to decreases in the rates of groundwater outflow and (or) increases in the rates of recharge along head-dependent boundaries of an aquifer in response to pumping. The second is a transport context, in which capture zone refers to the specific flowpaths that define the three-dimensional, volumetric portion of a groundwater flow field that discharges to a well...
March 15, 2018: Ground Water
Georges Hattab, Veit Wiesmann, Anke Becker, Tamara Munzner, Tim W Nattkemper
Time-lapse imaging of cell colonies in microfluidic chambers provides time series of bioimages, i.e., biomovies. They show the behavior of cells over time under controlled conditions. One of the main remaining bottlenecks in this area of research is the analysis of experimental data and the extraction of cell growth characteristics, such as lineage information. The extraction of the cell line by human observers is time-consuming and error-prone. Previously proposed methods often fail because of their reliance on the accurate detection of a single cell, which is not possible for high density, high diversity of cell shapes and numbers, and high-resolution images with high noise...
2018: Frontiers in Bioengineering and Biotechnology
Anthony R Vega, Spencer A Freeman, Sergio Grinstein, Khuloud Jaqaman
Molecular interactions are often transient and might change within the window of observation, leading to changes in molecule movement. Therefore, accurate motion analysis often requires transient motion classification. Here we present an accurate and computationally efficient transient mobility analysis framework, termed "divide-and-conquer moment scaling spectrum" (DC-MSS). DC-MSS works in a multistep fashion: 1) it utilizes a local movement descriptor throughout a track to divide it into initial segments of putatively different motion classes; 2) it classifies these segments via moment scaling spectrum (MSS) analysis of molecule displacements; and 3) it uses the MSS analysis results to refine the track segmentation...
March 13, 2018: Biophysical Journal
David Portehault, Simon Delacroix, Guillaume Gouget, Rémi Grosjean, Tsou-Hsi-Camille Chan-Chang
The design of inorganic nanoparticles relies strongly on the knowledge from solid-state chemistry not only for characterization techniques, but also and primarily for choosing the systems that will yield the desired properties. The range of inorganic solids reported and studied as nanoparticles is however strikingly narrow when compared to the solid-state chemistry portfolio of bulk materials. Efforts to enlarge the collection of inorganic particles are becoming increasingly important for three reasons. First, they can yield materials more performing than current ones for a range of fields including biomedicine, optics, catalysis, and energy...
March 13, 2018: Accounts of Chemical Research
Weixiang Jin, M Fethullah Simsek, Arnd Pralle
It has been long recognized that the cell membrane is heterogeneous on scales ranging from a couple of molecules to micrometers in size and hence diffusiong of receptors is length scale dependent. This heterogeneity modulates many cell-membrane-associated processes requiring transient spatiotemporal separation of components. The transient increase in local concentration of interacting signal components enables robust signaling in an otherwise thermally noisy system. Understanding how lipids and proteins self-organize and interact with the cell cortex requires quantifying the motion of the components...
March 9, 2018: Methods: a Companion to Methods in Enzymology
Hitomi Mukaibo, Tonghui Wang, Victor H Perez-Gonzalez, Jirachai Getpreecharsawas, Jack T Wurzer, Blanca Lapizco-Encinas, James L McGrath
Insulator-based dielectrophoresis (iDEP) is a simple, scalable mechanism that can be used for directly manipulating particle trajectories in pore-based filtration and separation processes. However, iDEP manipulation of nanoparticles presents unique challenges as the dielectrophoretic force (&lt;b&gt;&lt;i&gt;F&lt;/i&gt;&lt;/b&gt;&lt;sub&gt;DEP&lt;/sub&gt;) exerted on the nanoparticles can easily be overshadowed by opposing kinetic forces. In this study, a molecularly thin, SiN-based nanoporous membrane (NPN) is explored as a breakthrough technology that enhances &lt;b&gt;&lt;i&gt;F&lt;/i&gt;&lt;/b&gt;&lt;sub&gt;DEP&lt;/sub&gt;...
March 12, 2018: Nanotechnology
Shuang-Lin Deng, Yun-Qian Li, Gang Zhao
Objective: Gliomas are the most common neoplasm of the central nervous system (CNS); however, traditional imaging techniques do not show the boundaries of tumors well. Some researchers have found a new therapeutic mode to combine nanoparticles, which are nanosized particles with various properties for specific therapeutic purposes, and stem cells for tracing gliomas. This review provides an introduction of the basic understanding and clinical applications of the combination of stem cells and nanoparticles as a contrast agent for glioma imaging...
March 20, 2018: Chinese Medical Journal
Seiyed Mossa Hosseini, Tiziana Tosco, Behzad Ataie-Ashtiani, Craig T Simmons
Non-pumping reactive wells (NPRWs) filled by zero-valent iron (ZVI) can be utilized for the remediation of groundwater contamination of deep aquifers. The efficiency of NPRWs mainly depends on the hydraulic contact time (HCT) of the pollutant with the reactive materials, the extent of the well capture zone (Wcz ), and the relative hydraulic conductivity of aquifer and reactive material (Kr ). We investigated nitrate removal from groundwater using NPRWs filled by ZVI (in nano and micro scales) and examined the effect of NPRWs orientations (i...
February 27, 2018: Journal of Contaminant Hydrology
Hang Wu, Shixiang Wu, Nansheng Qiu, Jian Chang, Rima Bao, Xin Zhang, Nian Liu, Shuai Liu
Apatite fission-track (AFT) analysis, a widely used low-temperature thermochronology method, can provide details of the hydrocarbon generation history of source rocks for use in hydrocarbon exploration. The AFT method is based on the annealing behavior of fission tracks generated by238 U fission in apatite particles during geological history. Due to the cumbersome experimental steps and high expense, it is imperative to find an efficient and inexpensive technique to determinate the annealing degree of AFT. In this study, on the basis of the ellipsoid configuration of tracks, the track volume fraction model (TVFM) is established and the fission-track volume index is proposed...
January 1, 2018: Applied Spectroscopy
Ludmila Karen Dos Santos Silva, Ana Cláudia Dos Santos Pereira Andrade, Fábio Pio Dornas, Rodrigo Araújo Lima Rodrigues, Thalita Arantes, Erna Geessien Kroon, Cláudio Antônio Bonjardim, Jônatas Santos Abrahão
The giant viruses are the largest and most complex viruses in the virosphere. In the last decade, new members have constantly been added to this group. Here, we provide an in-depth descriptive analysis of the replication cycle of Cedratvirus getuliensis, one of the largest viruses known to date. We tracked the virion entry, the early steps of virus factory and particles morphogenesis, and during this phase, we observed a complex and unique sequential organization of immature particle elements, including horseshoe and rectangular compartments, revealed by transverse and longitudinal sections, respectively, until the formation of the final ovoid-shaped striped virion...
March 5, 2018: Scientific Reports
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...
March 2018: Radiation Research
Cindy M Yamamoto, Melanie L Oakes, Taku Murakami, Michael G Muto, Ross S Berkowitz, Shu-Wing Ng
BACKGROUND: Extracellular vesicles (EVs) are considered as a new class of resources for potential biomarkers. We analyzed expression of specific mRNA and miRNA in EVs derived from ovarian cancer ascites and the ideal controls, peritoneal fluids from benign patients for potential early detection and prognostic biomarkers. METHODS: Fluids were collected from subjects with benign cysts or endometrioma (n = 10), or low/high grade serous ovarian carcinoma (n = 8)...
March 2, 2018: Journal of Ovarian Research
Brian Shen, Beth L Armstrong, Mathieu Doucet, Luke Heroux, James F Browning, Michael Agamalian, Wyatt E Tenhaeff, Gabriel M Veith
We present a method to prepare shear-thickening electrolytes consisting of silica nanoparticles in conventional liquid electrolytes with limited flocculation. These electrolytes rapidly and reversibly stiffen to solid-like behaviors in the presence of external shear or high impact, which is promising for improved lithium ion battery safety, especially in elec-tric vehicles. However, in initial chemistries the silica nanoparticles aggregate and/or sediment in solution over time. Here, we demonstrate steric stabilization of silica colloids in conventional liquid electrolyte via surface-tethered PMMA brushes, synthesized via surface-initiated atom transfer radical polymerization...
March 2, 2018: ACS Applied Materials & Interfaces
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