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https://www.readbyqxmd.com/read/28741084/towards-the-prediction-of-flow-induced-shear-stress-distributions-experienced-by-breast-cancer-cells-in-the-lymphatics
#1
S T Morley, D T Newport, M T Walsh
Tumour metastasis in the lymphatics is a crucial step in the progression of breast cancer. The dynamics by which breast cancer cells (BCCs) travel in the lymphatics remains poorly understood. The goal of this work is to develop a model capable of predicting the shear stresses metastasising BCCs experience using numerical and experimental techniques. This paper models the fluidic transport of large particles ([Formula: see text] where [Formula: see text] is the particle diameter and W is the channel width) subjected to lymphatic flow conditions ([Formula: see text]), in a [Formula: see text] microchannel...
July 24, 2017: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/28740274/direct-evidence-of-atomic-scale-structural-fluctuations-in-catalyst-nanoparticles
#2
Pin Ann Lin, Jose L Gomez-Ballesteros, Juan C Burgos, Perla B Balbuena, Bharath Natarajan, Renu Sharma
Rational catalyst design requires an atomic scale mechanistic understanding of the chemical pathways involved in the catalytic process. A heterogeneous catalyst typically works by adsorbing reactants onto its surface, where the energies for specific bonds to dissociate and/or combine with other species (to form desired intermediate or final products) are lower. Here, using the catalytic growth of single-walled carbon nanotubes (SWCNTs) as a prototype reaction, we show that the chemical pathway may in-fact involve the entire catalyst particle, and can proceed via the fluctuations in the formation and decomposition of metastable phases in the particle interior...
May 2017: Journal of Catalysis
https://www.readbyqxmd.com/read/28737393/continuous-o2-evolving-mnfe2o4-nanoparticle-anchored-mesoporous-silica-nanoparticles-for-efficient-photodynamic-therapy-in-hypoxic-cancer
#3
Jonghoon Kim, Hye Rim Cho, Hyejin Jeon, Dokyoon Kim, Changyeong Song, Nohyun Lee, Seung Hong Choi, Taeghwan Hyeon
Cancer hypoxia, which involves a complex microenvironment ex-hibiting low O2 concentrations and nutrient deficiency, is known to prevent effective cancer treatment. In particular, the therapeutic effects of photodynamic therapy (PDT) are severely limited by cancer hypoxia, because the PDT process is strongly dependent on O2 concentration. Herein, we design and synthesize biocompatible manganese ferrite nanoparticle-anchored mesoporous silica nano-particles (MFMSNs) to overcome hypoxia, and consequently en-hancing the therapeutic efficiency of PDT...
July 24, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28735415/cfd-simulation-of-aerosol-delivery-to-a-human-lung-via-surface-acoustic-wave-nebulization
#4
Morteza Yousefi, Oveis Pourmehran, Mofid Gorji-Bandpy, Kiao Inthavong, Leslie Yeo, Jiyuan Tu
Administration of drug in the form of particles through inhalation is generally preferable in the treatment of respiratory disorders. Conventional inhalation therapy devices such as inhalers and nebulizers, nevertheless, suffer from low delivery efficiencies, wherein only a small fraction of the inhaled drug reaches the lower respiratory tract. This is primarily because these devices are not able to produce a sufficiently fine drug mist that has aerodynamic diameters on the order of a few microns. This study employs computational fluid dynamics to investigate the transport and deposition of the drug particles produced by a new aerosolization technique driven by surface acoustic waves (SAWs) into an in silico lung model geometrically reconstructed using computed tomography scanning...
July 22, 2017: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/28729949/modeling-the-effect-of-blunt-impact-on-mitochondrial-function-in-cartilage-implications-for-development-of-osteoarthritis
#5
Georgi I Kapitanov, Bruce P Ayati, James A Martin
OBJECTIVE: Osteoarthritis (OA) is a disease characterized by degeneration of joint cartilage. It is associated with pain and disability and is the result of either age and activity related joint wear or an injury. Non-invasive treatment options are scarce and prevention and early intervention methods are practically non-existent. The modeling effort presented in this article is constructed based on an emerging biological hypothesis-post-impact oxidative stress leads to cartilage cell apoptosis and hence the degeneration observed with the disease...
2017: PeerJ
https://www.readbyqxmd.com/read/28729861/comparative-omics-and-trait-analyses-of-marine-pseudoalteromonas-phages-advance-the-phage-otu-concept
#6
Melissa B Duhaime, Natalie Solonenko, Simon Roux, Nathan C Verberkmoes, Antje Wichels, Matthew B Sullivan
Viruses influence the ecology and evolutionary trajectory of microbial communities. Yet our understanding of their roles in ecosystems is limited by the paucity of model systems available for hypothesis generation and testing. Further, virology is limited by the lack of a broadly accepted conceptual framework to classify viral diversity into evolutionary and ecologically cohesive units. Here, we introduce genomes, structural proteomes, and quantitative host range data for eight Pseudoalteromonas phages isolated from Helgoland (North Sea, Germany) and use these data to advance a genome-based viral operational taxonomic unit (OTU) definition...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28728434/economic-model-predictive-control-of-bihormonal-artificial-pancreas-system-based-on-switching-control-and-dynamic-r-parameter
#7
Fengna Tang, Youqing Wang
BACKGROUND: Blood glucose (BG) regulation is a long-term task for people with diabetes. In recent years, more and more researchers have attempted to achieve automated regulation of BG using automatic control algorithms, called the artificial pancreas (AP) system. In clinical practice, it is equally important to guarantee the treatment effect and reduce the treatment costs. The main motivation of this study is to reduce the cure burden. METHODS: The dynamic R-parameter economic model predictive control (R-EMPC) is chosen to regulate the delivery rates of exogenous hormones (insulin and glucagon)...
July 1, 2017: Journal of Diabetes Science and Technology
https://www.readbyqxmd.com/read/28723144/inflection-point-of-the-localized-surface-plasmon-resonance-peak-a-general-method-to-improve-the-sensitivity
#8
Peng Chen, Nhung Thi Tran, Xinglin Wen, Qihua Xiong, Bo Liedberg
The shift of the localized surface plasmon resonance (LSPR) spectrum is widely used in bio- and chemical sensing. Traditionally, the shift is monitored at the peak maximum of the extinction spectrum. We demonstrate that the inflection point at the long wavelength side of the peak maximum shows better refractive index sensitivity than the peak maximum. A consistent improvement in bulk refractive index sensitivity of 18-55% is observed for six different nanoparticles such as spherical particles of different sizes, nanostar and nanorods with different aspect ratios...
February 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28722824/local-equilibrium-and-retardation-revisited
#9
Scott K Hansen, Velimir V Vesselinov
In modeling solute transport with mobile-immobile mass transfer (MIMT), it is common to use an advection-dispersion equation (ADE) with a retardation factor, or retarded ADE. This is commonly referred to as making the local equilibrium assumption (LEA). Assuming local equilibrium, Eulerian textbook treatments derive the retarded ADE, ostensibly exactly. However, other authors have presented rigorous mathematical derivations of the dispersive effect of MIMT, applicable even in the case of arbitrarily fast mass transfer...
July 19, 2017: Ground Water
https://www.readbyqxmd.com/read/28718204/detrital-shadows-estuarine-food-web-connectivity-depends-on-fluvial-influence-and-consumer-feeding-mode
#10
Emily Howe, Charles A Simenstad, Andrea Ogston
We measured the influence of landscape setting on estuarine food web connectivity in five macrotidal Pacific Northwest estuaries across a gradient of freshwater influence. We used stable isotopes (δ(13) C, δ(15) N, δ(34) S) in combination with a Bayesian mixing model to trace primary producer contributions to suspension- and deposit-feeding bivalve consumers (Mytilus trossulus and Macoma nasuta) transplanted into three estuarine vegetation zones: emergent marsh, mudflat, Japanese eelgrass (Zostera japonica), and native eelgrass (Zostera marina)...
July 17, 2017: Ecological Applications: a Publication of the Ecological Society of America
https://www.readbyqxmd.com/read/28717425/high-throughput-nanoparticle-tracking-analysis-for-monitoring-outer-membrane-vesicle-production
#11
Matthias J H Gerritzen, Dirk E Martens, René H Wijffels, Michiel Stork
Outer membrane vesicles (OMVs) are spherical membrane nanoparticles released by Gram-negative bacteria. OMVs can be quantified in complex matrices by nanoparticle tracking analysis (NTA). NTA can be performed in static mode or with continuous sample flow that results in analysis of more particles in a smaller time-frame. Flow measurements must be performed manually despite the availability of a sample changer on the NanoSight system. Here we present a method for automated measurements in flow mode. OMV quantification in flow mode results in lower variance in particle quantification (coefficient of variation (CV) of 6%, CV static measurements of 14%)...
2017: Journal of Extracellular Vesicles
https://www.readbyqxmd.com/read/28711013/seeing-the-unseen-imaging-rotation-in-cells-with-designer-anisotropic-particles
#12
REVIEW
Yuan Gao, Yanqi Yu, Lucero Sanchez, Yan Yu
Cellular functions are enabled by cascades of transient biological events. Imaging and tracking the dynamics of these events have proven to be a powerful means of understanding the principles of cellular processes. These studies have typically focused on translational dynamics. By contrast, investigations of rotational dynamics have been scarce, despite emerging evidence that rotational dynamics are an inherent feature of many cellular processes and may also provide valuable clues to understanding those cell functions...
July 8, 2017: Micron: the International Research and Review Journal for Microscopy
https://www.readbyqxmd.com/read/28709267/aggregation-and-fragmentation-dynamics-in-random-flows-from-tracers-to-inertial-aggregates
#13
Ksenia Guseva, Ulrike Feudel
We investigate the aggregation and fragmentation dynamics of tracers and inertial aggregates in random flows leading to steady-state size distributions. Our objective is to elucidate the impact of changes in aggregation rates due to differences in advection dynamics, especially with respect to the influence of inertial effects. This aggregation process is, at the same time, balanced by fragmentation triggered by local hydrodynamic stress. Our study employs an individual-particle-based model, tracking the position, velocity, and size of each aggregate...
June 2017: Physical Review. E
https://www.readbyqxmd.com/read/28708889/a-new-index-for-characterizing-micro-bead-motion-in-a-flow-induced-by-ciliary-beating-part-i-experimental-analysis
#14
Mathieu Bottier, Sylvain Blanchon, Gabriel Pelle, Emilie Bequignon, Daniel Isabey, André Coste, Estelle Escudier, James B Grotberg, Jean-François Papon, Marcel Filoche, Bruno Louis
Mucociliary clearance is one of the major lines of defense of the respiratory system. The mucus layer coating the pulmonary airways is moved along and out of the lung by the activity of motile cilia, thus expelling the particles trapped in it. Here we compare ex vivo measurements of a Newtonian flow induced by cilia beating (using micro-beads as tracers) and a mathematical model of this fluid flow, presented in greater detail in a second companion article. Samples of nasal epithelial cells placed in water are recorded by high-speed video-microscopy and ciliary beat pattern is inferred...
July 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28701768/microstructural-evolution-during-sintering-of-copper-particles-studied-by-laboratory-diffraction-contrast-tomography-labdct
#15
S A McDonald, C Holzner, E M Lauridsen, P Reischig, A P Merkle, P J Withers
Pressureless sintering of loose or compacted granular bodies at elevated temperature occurs by a combination of particle rearrangement, rotation, local deformation and diffusion, and grain growth. Understanding of how each of these processes contributes to the densification of a powder body is still immature. Here we report a fundamental study coupling the crystallographic imaging capability of laboratory diffraction contrast tomography (LabDCT) with conventional computed tomography (CT) in a time-lapse study...
July 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28698382/phosphatidylserine-dictates-the-assembly-and-dynamics-of-caveolae-in-the-plasma-membrane
#16
Takashi Hirama, Raibatak Das, Yanbo Yang, Charles Ferguson, Amy Won, Christopher M Yip, Jason G Kay, Sergio Grinstein, Robert G Parton, Gregory D Fairn
Caveolae are bulb-shaped nanodomains of the plasma membrane that are enriched in cholesterol and sphingolipids. They have many physiological functions, including endocytic transport, mechanosensing, and regulation of membrane and lipid transport. Caveola formation relies on integral membrane proteins termed caveolins (CAVs) and the cavin family of peripheral proteins. Both protein families bind anionic phospholipids, but the precise roles of these lipids are unknown. Here, we studied the effects of phosphatidylserine (PtdSer), phosphatidylinositol 4-phosphate (PtdIns4P), and phosphatidylinositol 4,5-bisphosphate (PtdIns4,5P2) on caveolar formation and dynamics...
July 11, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28698220/activation-of-camkiv-by-soluble-amyloid-%C3%AE-1-42-impedes-trafficking-of-axonal-vesicles-and-impairs-activity-dependent-synaptogenesis
#17
Daehun Park, Myeongsu Na, Jung Ah Kim, Unghwi Lee, Eunji Cho, Mirye Jang, Sunghoe Chang
The prefibrillar form of soluble amyloid-β (sAβ1-42) impairs synaptic function and is associated with the early phase of Alzheimer's disease (AD). We investigated how sAβ1-42 led to presynaptic defects using a quantum dot-based, single particle-tracking method to monitor synaptic vesicle (SV) trafficking along axons. We found that sAβ1-42 prevented new synapse formation induced by chemical long-term potentiation (cLTP). In cultured rat hippocampal neurons, nanomolar amounts of sAβ1-42 impaired Ca(2+) clearance from presynaptic terminals and increased the basal Ca(2+) concentration...
July 11, 2017: Science Signaling
https://www.readbyqxmd.com/read/28696315/size-and-mobility-of-lipid-domains-tuned-by-geometrical-constraints
#18
Ole M Schütte, Ingo Mey, Jörg Enderlein, Filip Savić, Burkhard Geil, Andreas Janshoff, Claudia Steinem
In the plasma membrane of eukaryotic cells, proteins and lipids are organized in clusters, the latter ones often called lipid domains or "lipid rafts." Recent findings highlight the dynamic nature of such domains and the key role of membrane geometry and spatial boundaries. In this study, we used porous substrates with different pore radii to address precisely the extent of the geometric constraint, permitting us to modulate and investigate the size and mobility of lipid domains in phase-separated continuous pore-spanning membranes (PSMs)...
July 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28691108/jetting-of-a-shear-banding-fluid-in-rectangular-ducts
#19
Paul F Salipante, Charles A E Little, Steven D Hudson
Non-Newtonian fluids are susceptible to flow instabilities such as shear banding, in which the fluid may exhibit a markedly discontinuous viscosity at a critical stress. Here we report the characteristics and causes of a jetting flow instability of shear banding wormlike micelle solutions in microfluidic channels with rectangular cross sections over an intermediate volumetric flow regime. Particle-tracking methods are used to measure the three-dimensional flow field in channels of differing aspect ratios, sizes, and wall materials...
March 2017: Physical Review Fluids
https://www.readbyqxmd.com/read/28690715/a-novel-aerodynamic-sizing-method-for-pharmaceutical-aerosols-using-image-based-analysis-of-settling-velocities
#20
Rami Fishler, Josué Sznitman
This article discusses a novel method to estimate aerodynamic particle size distributions (APSDs) of pharmaceutical aerosols through direct measurement of particle settling velocities using image-based analysis and particle tracking techniques. This simple, optical method provides accurate and fast measurements (approximately 1 minute) with few sources of bias due to specific device design choices or operation conditions. A proof-of-concept for the method is demonstrated by measuring APSDs for widely available commercial dry powder inhalers (DPIs), then comparing the results with previously published data from cascade impactors (CIs) and the Aerodynamic Particle Sizer (APS)...
June 2017: Inhalation
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