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particle tracking

François-Gaël Michalec, Markus Holzner, Alexandre Barras, Anne-Sophie Lacoste, Loïc Brunet, Jae-Seong Lee, Christian Slomianny, Rabah Boukherroub, Sami Souissi
Calanoid copepods play an important role in the functioning of marine and brackish ecosystems. Information is scarce on the behavioral toxicity of engineered nanoparticles to these abundant planktonic organisms. We assessed the effects of short-term exposure to nonfunctionalized gold nanoparticles on the swimming behavior of the widespread estuarine copepod Eurytemora affinis. By means of three-dimensional particle tracking velocimetry, we reconstructed the trajectories of males, ovigerous and non-ovigerous females...
May 17, 2017: Environmental Pollution
T W Jeong, P K Singh, C Scullion, H Ahmed, P Hadjisolomou, C Jeon, H Yun, K F Kakolee, M Borghesi, S Ter-Avetisyan
We present the characteristics of track formation on the front and rear surfaces of CR-39 produced by laser-driven protons and carbon ions. A methodological approach, based on bulk etch length, is proposed to uniquely characterize the particle tracks in CR-39, enabling comparative description of the track characteristics in different experiments. The response of CR-39 to ions is studied based on the energy dependent growth rate of the track diameter to understand the intrinsic particle stopping process within the material...
May 19, 2017: Scientific Reports
Jared Q Gerlach, Ciaran M Maguire, Anja Krüger, Lokesh Joshi, Adriele Prina-Mello, Matthew D Griffin
AIM: The use of carbohydrate-binding proteins (lectins) to isolate urinary extracellular vesicles (uEVs) was investigated and the captured subpopulations were characterized. METHODS: Pooled uEVs from multiple healthy donors were exposed to lectin-conjugated or antibody-conjugated beads. Recovered uEVs were evaluated by protein estimation, transmission electron microscopy, nanoparticle tracking analysis and lectin microarray profiling. RESULTS: uEVs isolated by lectin- and antibody-based affinity capture exhibited distinct variations in size and surface content...
May 18, 2017: Nanomedicine
Hao Shen, Lawrence J Tauzin, Rashad Baiyasi, Wenxiao Wang, Nicholas Moringo, Bo Shuang, Christy F Landes
After three decades of developments, single particle tracking (SPT) has become a powerful tool to interrogate dynamics in a range of materials including live cells and novel catalytic supports because of its ability to reveal dynamics in the structure-function relationships underlying the heterogeneous nature of such systems. In this review, we summarize the algorithms behind, and practical applications of, SPT. We first cover the theoretical background including particle identification, localization, and trajectory reconstruction...
May 18, 2017: Chemical Reviews
E Bagnaschi, M Borsato, K Sakurai, O Buchmueller, R Cavanaugh, V Chobanova, M Citron, J C Costa, A De Roeck, M J Dolan, J R Ellis, H Flächer, S Heinemeyer, G Isidori, M Lucio, F Luo, D Martínez Santos, K A Olive, A Richards, G Weiglein
We perform a likelihood analysis of the minimal anomaly-mediated supersymmetry-breaking (mAMSB) model using constraints from cosmology and accelerator experiments. We find that either a wino-like or a Higgsino-like neutralino LSP, [Formula: see text], may provide the cold dark matter (DM), both with similar likelihoods. The upper limit on the DM density from Planck and other experiments enforces [Formula: see text] after the inclusion of Sommerfeld enhancement in its annihilations. If most of the cold DM density is provided by the [Formula: see text], the measured value of the Higgs mass favours a limited range of [Formula: see text] (and also for [Formula: see text] if [Formula: see text]) but the scalar mass [Formula: see text] is poorly constrained...
2017: European Physical Journal. C, Particles and Fields
I-Hsuan Wang, Christoph J Burckhardt, Artur Yakimovich, Matthias K Morf, Urs F Greber
Transport of large cargo through the cytoplasm requires motor proteins and polarized filaments. Viruses that replicate in the nucleus of post-mitotic cells use microtubules and the dynein/dynactin motor to traffic to the nuclear membrane, and deliver their genome through nuclear pore complexes (NPCs) into the nucleus. How virus particles (virions) or cellular cargo are transferred from microtubules to the NPC is unknown. Here, we analyzed trafficking of incoming cytoplasmic adenoviruses by single particle tracking and super-resolution microscopy...
May 17, 2017: Journal of Cell Science
Martin Donnelley, Kaye S Morgan, Maged Awadalla, Nigel R Farrow, Chris Hall, David W Parsons
BACKGROUND: The Australian Synchrotron Imaging and Medical Beamline (IMBL) was designed as the world's widest synchrotron X-ray beam, enabling both clinical imaging and therapeutic applications for humans as well as the imaging of large animal models. Our group is developing methods for imaging the airways of newly developed CF animal models that display human-like lung disease, such as the CF pig, and we expect that the IMBL can be utilised to image airways in animals of this size. METHODS: This study utilised samples of excised tracheal tissue to assess the feasibility, logistics and protocols required for airway imaging in large animal models such as pigs and sheep at the IMBL...
May 16, 2017: Respiratory Research
Xiaohui Liu, Ting Ouyang, Hongsheng Ouyang, Linzhu Ren
Real-time and visual tracking of viral infection is crucial for elucidating the infectious and pathogenesis mechanisms. To track the virus successfully, an efficient labeling method is necessary. In this review, we first discuss the practical labeling techniques for virus tracking in live cells. We then describe the current knowledge of interactions between RNA viruses (especially influenza viruses, immunodeficiency viruses, and Flaviviruses) and host cellular structures, obtained using single particle labeling techniques combined with real-time fluorescence microscopy...
May 12, 2017: Virus Research
Lachlan J Gibson, Shu Zhang, Alexander B Stilgoe, Timo A Nieminen, Halina Rubinsztein-Dunlop
Active particle tracking microrheometers have the potential to perform accurate broadband measurements of viscoelasticity within microscopic systems. Generally, their largest possible precision is limited by Brownian motion and low frequency changes to the system. The signal to noise ratio is usually improved by increasing the size of the driven motion compared to the Brownian as well as averaging over repeated measurements. New theory is presented here whereby error in measurements of the complex shear modulus can be significantly reduced by analyzing the motion of a spherical particle driven by nonlinear forces...
April 2017: Physical Review. E
Nerea Epelde-Elezcano, Ruth Prieto-Montero, Virginia Martínez-Martínez, María J Ortiz, Alejandro Prieto-Castañeda, Eduardo Peña-Cabrera, José L Belmonte-Vázquez, Iñigo López-Arbeloa, Ross Brown, Sylvie Lacombe
A modified Stöber method is used to synthesize spherical core-shell silica nanoparticles (NPs) with an external surface functionalized by amino groups and with an average size around 50 nm. Fluorescent dyes and photosensitizers of singlet oxygen were fixed, either separately or conjointly, respectively in the core or in the shell. Rhodamines were encapsulated in the core with relatively high fluorescence quantum yields (Φfl ≥ 0.3), allowing fluorescence tracking of the particles. Various photosensitizers of singlet oxygen (PS) were covalenty coupled to the shell, allowing singlet oxygen production...
May 15, 2017: Physical Chemistry Chemical Physics: PCCP
Xavier Llovet, Francesc Salvat
The Monte Carlo program PENEPMA performs simulations of X-ray emission from samples bombarded with both electron and photon beams. It is based on the general-purpose Monte Carlo simulation package PENELOPE, an elaborate system for the simulation of coupled electron-photon transport in arbitrary materials, and on the geometry subroutine package PENGEOM, which tracks particles through complex material structures defined by quadric surfaces. After a brief description of the interaction models implemented in the simulation subroutines and of the structure and operation of PENEPMA, we provide an overview of the capabilities of the program along with several examples of its application to the modeling of electron probe microanalysis measurements...
May 15, 2017: Microscopy and Microanalysis
Francis A Cucinotta, Eliedonna Cacao
Cancer risk is an important concern for galactic cosmic ray (GCR) exposures, which consist of a wide-energy range of protons, heavy ions and secondary radiation produced in shielding and tissues. Relative biological effectiveness (RBE) factors for surrogate cancer endpoints in cell culture models and tumor induction in mice vary considerable, including significant variations for different tissues and mouse strains. Many studies suggest non-targeted effects (NTE) occur for low doses of high linear energy transfer (LET) radiation, leading to deviation from the linear dose response model used in radiation protection...
May 12, 2017: Scientific Reports
Irene Maria Hansen, Morten Frendø Ebbesen, Liselotte Kaspersen, Troels Thomsen, Konrad Bienk, Yunpeng Cai, Birgitte Mølholm Malle, Kenneth Alan Howard
This study investigates the effects of different molecular weight hyaluronic acid (HA) on the mucosal nanostructure using a pig stomach mucin hydrogel as a mucosal barrier model. Micro- (1.0 µm) and nanoparticles (200 nm) were used as probes and their movement in mucin was studied by a 3D confocal microscopy-based particle tracking technique and by nanoparticle tracking analysis (NTA) after addition of high (900 kDa) and low (33 kDa) molecular weight HA. This demonstrated a molecular weight-dependent HA modulation of the mucin nanostructure with a 2...
May 12, 2017: Molecular Pharmaceutics
Chun-Ting Kuo, Hong-Shang Peng, Yu Rong, Jiangbo Yu, Wei Sun, Bryant S Fujimoto, Daniel T Chiu
Multiplexed optical encoding is emerging as a powerful technique for high-throughput cellular analysis and molecular assays. Most of the developed optical barcodes, however, either suffer from large particle size or are incompatible with most commercial optical instruments. Here, a new type of nanoscale fluorescent barcodes (Pdot barcodes) was prepared from semiconducting polymers. The Pdot barcodes possess the merits of small size (~20 nm in diameter), narrow emission bands (FWHM of 30-40 nm), three-color emissions (blue, green, and red) under single-wavelength excitation, a high brightness, good pH and thermal stability, and efficient cellular uptake...
May 12, 2017: Analytical Chemistry
Laura Alvarez, M Paul Lettinga, Eric Grelet
We investigate the dynamic behavior of long guest rodlike particles immersed in liquid crystalline phases formed by shorter host rods, tracking both guest and host particles by fluorescence microscopy. Counterintuitively, we evidence that long rods diffuse faster than short rods forming the one-dimensional ordered smectic-A phase. This results from the larger and noncommensurate size of the guest particles as compared to the wavelength of the energy landscape set by the lamellar stack of liquid slabs. The long guest particles are also shown to be still mobile in the crystalline smectic-B phase, as they generate their own voids in the adjacent layers...
April 28, 2017: Physical Review Letters
Ting Wang, Lu Wang, Xiaoming Li, Xingjie Hu, Yuping Han, Yao Luo, Zejun Wang, Qian Li, Ali Aldalbahi, Lihua Wang, Shiping Song, Chunhai Fan, Yun Zhao, Maolin Wang, Nan Chen
Nanoparticles (NPs) have shown great promise as intracellular imaging probes or nanocarriers and play increasing role in biomedical applications. A detailed understanding of how NPs get "in and out" of cells is important for developing new nanomaterials with improved selectivity and less cytotoxicity. Both physical and chemical characteristics have proven to regulate the cellular uptake of nanoparticles. However, the exocytosis process and its regulation are less explored. Herein, we investigated the size-regulated endocytosis and exocytosis of carboxylated polystyrene (PS) nanoparticles...
May 12, 2017: ACS Applied Materials & Interfaces
Michael Mak, Sarah Anderson, Meghan C McDonough, Fabian Spill, Jessica E Kim, Alexandra Boussommier-Calleja, Muhammad H Zaman, Roger D Kamm
The intracellular environment is composed of a filamentous network that exhibits dynamic turnover of cytoskeletal components and internal force generation from molecular motors. Particle tracking microrheology enables a means to probe the internal mechanics and dynamics. Here, we develop an analytical model to capture the basic features of the active intracellular mechanical environment, including both thermal and motor-driven effects, and show consistency with a diverse range of experimental microrheology data...
May 9, 2017: Biophysical Journal
Heinrich Rübsam, Thomas Becker, Martina Gastl
The changes on the molecular weight distribution (MWD) and particle size distribution (PSD) during hydrolysis of barley malt in isothermal mashing procedures were determined using asymmetrical flow field flow fractionation coupled to multiangle laser light scattering and refractive index (AF4/MALS/RI). Mash/trials were focused on amylolytic starch degradation. Therefore, temperatures (65, 70, and 75 °C) were selected according to α- and β-amylases range of activity. Samples were produced by triplicate, tracking amylolytic processes over time periods from 10 to 90 min in each mash/trial...
May 10, 2017: Journal of Food Science
Yann Chalopin, Jean-Claude Bacri, Florence Gazeau, Martin Devaud
Clusters of magnetic nanoparticles have received considerable interest in various research fields. Their capacity to generate heat under an alternating magnetic field has recently opened the way to applications such as cancer therapy by hyperthermia. This work is an attempt to investigate the collective effects of interacting dipoles embedded in magnetic nano-particles (MNP) to predict their thermal dissipation with a liquid. We first present a general approach, based on the tracking of the microscopic dipole fluctuations, to access to the dissipation spectra of any spatial distribution of MNPs...
May 10, 2017: Scientific Reports
A U Krupp, I M Griffiths, C P Please
Membrane fouling during particle filtration occurs through a variety of mechanisms, including internal pore clogging by contaminants, coverage of pore entrances and deposition on the membrane surface. In this paper, we present an efficient method for modelling the behaviour of a filter, which accounts for different retention mechanisms, particle sizes and membrane geometries. The membrane is assumed to be composed of a series of, possibly interconnected, pores. The central feature is a conductivity function, which describes the blockage of each individual pore as particles arrive, which is coupled with a mechanism to account for the stochastic nature of the arrival times of particles at the pore...
April 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
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