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field flow fractionation

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https://www.readbyqxmd.com/read/28315484/probing-fast-ribozyme-reactions-under-biological-conditions-with-rapid-quench-flow-kinetics
#1
Jamie L Bingaman, Kyle J Messina, Philip C Bevilacqua
Reaction kinetics on the millisecond timescale pervade the protein and RNA fields. To study such reactions, investigators often perturb the system with abiological solution conditions or substrates in order to slow the rate to timescales accessible by hand-mixing; however, such perturbations can change the rate-limiting step and obscure key folding and chemical steps that are found under biological conditions. Mechanical methods for collecting data on the millisecond timescale, which allow these perturbations to be avoided, have been developed over the last few decades...
March 14, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28290585/size-and-property-bimodality-in-magnetic-nanoparticle-dispersions-single-domain-particles-vs-strongly-coupled-nanoclusters
#2
E Wetterskog, A Castro, L Zeng, S Petronis, D Heinke, E Olsson, L Nilsson, N Gehrke, P Svedlindh
The widespread use of magnetic nanoparticles in the biotechnical sector puts new demands on fast and quantitative characterization techniques for nanoparticle dispersions. In this work, we report the use of asymmetric flow field-flow fractionation (AF4) and ferromagnetic resonance (FMR) to study the properties of a commercial magnetic nanoparticle dispersion. We demonstrate the effectiveness of both techniques when subjected to a dispersion with a bimodal size/magnetic property distribution: i.e., a small superparamagnetic fraction, and a larger blocked fraction of strongly coupled colloidal nanoclusters...
March 14, 2017: Nanoscale
https://www.readbyqxmd.com/read/28290362/study-on-external-factors-affecting-egg-yolk-plasma-by-asymmetrical-flow-field-flow-fractionation
#3
Haiyang Dou, Xiaoyue Zhang, Aixia Zhang, Jaeyeong Choi, Jing Wang, Shigang Shen, Wenhui Zhang, Yueqiu Li, Liang Ding, Seungho Lee
In this work, the ability of asymmetrical flow field-flow fractionation (AF4) coupled with UV-vis, multiangle light scattering (MALS), and quasi-elastic light scattering (QELS) (AF4-UV-MALS-QELS) for monitoring aggregation of components of egg yolk plasma was evaluated. The effect of external factors (i.e., pH, storage conditions, freezing and heat treatments) on the egg yolk plasma was studied. The results reveal that the aggregation mechanism of components of egg yolk plasma during heat and freezing treatment is different...
April 2017: Food Research International
https://www.readbyqxmd.com/read/28288312/evaluation-of-thermally-modified-calcium-rich-attapulgite-as-a-low-cost-substrate-for-rapid-phosphorus-removal-in-constructed-wetlands
#4
Hongbin Yin, Xiaowei Yan, Xiaohong Gu
The cost-effective and geographically available substrates are vital for the design of constructed wetlands (CWs), especially the saturated subsurface flow CWs, which are deemed as an efficient way to remove the inlet-lake phosphorus concentrations. In this study, phosphorus removal of thermally-treated calcium-rich attapulgite (TCAP) with varied particle sizes (0.2-0.5 mm, 0.5-1 mm and 1-2 mm) was assessed using batch and long-term column experiments to evaluate its feasibility as a CWs substrate. The phosphorus-bound mechanism in TCAP was identified in various initial phosphorus concentrations...
March 6, 2017: Water Research
https://www.readbyqxmd.com/read/28272897/magnetic-switching-in-granular-fept-layers-promoted-by-near-field-laser-enhancement
#5
Patrick W Granitzka, Emmanuelle Jal, Loïc Le Guyader, Matteo Savoini, Daniel J Higley, Tianmin Liu, Zhao Chen, Tyler Chase, Hendrik Ohldag, Georgi L Dakovski, William F Schlotter, Sebastian Carron, Matthias C Hoffman, Alexander X Gray, Padraic Shafer, Elke Arenholz, Olav Hellwig, Virat Mehta, Yukiko K Takahashi, Jian Wang, Eric E Fullerton, Joachim Stöhr, Alexander H Reid, Hermann A Dürr
Light-matter interaction at the nanoscale in magnetic materials is a topic of intense research in view of potential applications in next-generation high-density magnetic recording. Laser-assisted switching provides a pathway for overcoming the material constraints of high-anisotropy and high-packing density media, though much about the dynamics of the switching process remains unexplored. We use ultrafast small-angle X-ray scattering at an X-ray free-electron laser to probe the magnetic switching dynamics of FePt nanoparticles embedded in a carbon matrix following excitation by an optical femtosecond laser pulse...
March 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/28269446/current-distribution-in-tissues-with-conducted-electrical-weapons-operated-in-drive-stun-mode
#6
Dorin Panescu, Mark W Kroll, Michael Brave
INTRODUCTION: The TASER® conducted electrical weapon (CEW) is best known for delivering electrical pulses that can temporarily incapacitate subjects by overriding normal motor control. The alternative drive-stun mode is less understood and the goal of this paper is to analyze the distribution of currents in tissues when the CEW is operated in this mode. METHODS AND RESULTS: Finite element modeling (FEM) was used to approximate current density in tissues with boundary electrical sources placed 40 mm apart...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227692/current-distribution-in-tissues-with-conducted-electrical-weapons-operated-in-drive-stun-mode
#7
Dorin Panescu, Mark W Kroll, Michael Brave, Dorin Panescu, Mark W Kroll, Michael Brave, Dorin Panescu, Mark W Kroll, Michael Brave
INTRODUCTION: The TASER® conducted electrical weapon (CEW) is best known for delivering electrical pulses that can temporarily incapacitate subjects by overriding normal motor control. The alternative drive-stun mode is less understood and the goal of this paper is to analyze the distribution of currents in tissues when the CEW is operated in this mode. METHODS AND RESULTS: Finite element modeling (FEM) was used to approximate current density in tissues with boundary electrical sources placed 40 mm apart...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28211739/microscopic-description-of-the-granular-fluidity-field-in-nonlocal-flow-modeling
#8
Qiong Zhang, Ken Kamrin
A recent granular rheology based on an implicit "granular fluidity" field has been shown to quantitatively predict many nonlocal phenomena. However, the physical nature of the field has not been identified. Here, the granular fluidity is found to be a kinematic variable given by the velocity fluctuation and packing fraction. This is verified with many discrete element simulations, which show that the operational fluidity definition, solutions of the fluidity model, and the proposed microscopic formula all agree...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28208349/effects-of-gas-interparticle-interaction-on-dissipative-wake-mediated-forces
#9
O V Kliushnychenko, S P Lukyanets
We examine how the short-range repulsive interaction in a gas of Brownian particles affects behavior of the nonequilibrium depletion forces between obstacles embedded into the gas flow. It is shown that for an ensemble of small and widely separated obstacles the dissipative wake-mediated interaction belongs to the type of induced dipole-dipole interaction governed by an anisotropic screened Coulomb-like potential. For closely located obstacles, formation of a common density perturbation "coat" around them leads to enhancement of dissipative interaction, manifested by characteristic peaks in its dependence on both the bath fraction and the external driving field...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28196092/characterization-of-cereal-%C3%AE-glucan-extracts-from-oat-and-barley-and-quantification-of-proteinaceous-matter
#10
Claudia Zielke, Ondrej Kosik, Marie-Louise Ainalem, Alison Lovegrove, Anna Stradner, Lars Nilsson
An extraction method for mixed-linkage β-glucan from oat and barley was developed in order to minimize the effect of extraction on the β-glucan structure. β-Glucan were characterized in terms of molecular size and molar mass distributions using asymmetric flow field-flow fractionation (AF4) coupled to multiangle light scattering (MALS), differential refractive index (dRI) and fluorescence (FL) detection. The carbohydrate composition of the extracts was analysed using polysaccharide analysis by carbohydrate gel electrophoresis (PACE) and high-performance anion-exchange chromatography (HPAEC)...
2017: PloS One
https://www.readbyqxmd.com/read/28194836/quantitative-characterization-of-the-carbon-carbon-composites-components-based-on-video-of-polarized-light-microscope
#11
Yixian Li, Lehua Qi, Yongshan Song, Xujiang Chao
The components of carbon/carbon (C/C) composites have significant influence on the thermal and mechanical properties, so a quantitative characterization of component is necessary to study the microstructure of C/C composites, and further to improve the macroscopic properties of C/C composites. Considering the extinction crosses of the pyrocarbon matrix have significant moving features, the polarized light microscope (PLM) video is used to characterize C/C composites quantitatively because it contains sufficiently dynamic and structure information...
February 13, 2017: Microscopy Research and Technique
https://www.readbyqxmd.com/read/28193064/vapor-pressure-isotope-effects-in-halogenated-organic-compounds-and-alcohols-dissolved-in-water
#12
Axel Horst, Georges Lacrampe-Couloume, Barbara Sherwood Lollar
Volatilization causes changes in the isotopic composition of organic compounds as a result of different vapor pressures of molecules containing heavy and light isotopes. Both normal and inverse vapor pressure isotope effects (VPIE) have been observed, depending on molecular interactions in the liquid phase and the investigated element. Previous studies have focused mostly on pure compound volatilization or on compounds dissolved in organic liquids. Environmentally relevant scenarios, such as isotope fractionation during volatilization of organics from open water surfaces, have largely been neglected...
December 20, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/28192938/size-dependent-lipidomic-analysis-of-urinary-exosomes-from-patients-with-prostate-cancer-by-flow-field-flow-fractionation-and-nanoflow-liquid-chromatography-tandem-mass-spectrometry
#13
Joon Seon Yang, Jong Cheol Lee, Seul Kee Byeon, Koon Ho Rha, Myeong Hee Moon
Exosomes are membrane-bound extracellular vesicles involved in intercellular communication and tumor cell metastasis. In this study, flow field-flow fractionation (FlFFF) was utilized to separate urinary exosomes by size, demonstrating a significant difference in exosome sizes between healthy controls and patients with prostate cancer (PCa). Exosome fractions of different sizes were collected for microscopic analysis during an FlFFF run and evaluated with exosome marker proteins using Western blot analysis...
February 2, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28180990/asymmetrical-flow-field-flow-fractionation-of-white-wine-chromophoric-colloidal-matter
#14
Christian Coelho, Jérémie Parot, Michael Gonsior, Maria Nikolantonaki, Philippe Schmitt-Kopplin, Edith Parlanti, Régis D Gougeon
Two analytical separation methods-size-exclusion chromatography and asymmetrical flow field-flow fractionation-were implemented to evaluate the integrity of the colloidal composition of Chardonnay white wine and the impact of pressing and fermentations on the final macromolecular composition. Wine chromophoric colloidal matter, representing UV-visible-absorbing wine macromolecules, was evaluated by optical and structural measurements combined with the description of elution profiles obtained by both separative techniques...
April 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28154161/development-of-coronary-pulse-wave-velocity-new-pathophysiological-insight-into-coronary-artery-disease
#15
Brahim Harbaoui, Pierre-Yves Courand, Andrei Cividjian, Pierre Lantelme
BACKGROUND: Although aortic stiffness assessed by pulse wave velocity (PWV) is a strong predictor of coronary artery disease, the significance of local coronary stiffness has never been tackled. The first objective of this study was to describe a method of measuring coronary PWV (CoPWV) invasively and to describe its determinants. The second objective was to assess both CoPWV and aortic PWV in patients presenting with acute coronary syndromes or stable coronary artery disease. METHODS AND RESULTS: In 53 patients, CoPWV was measured from the delay in pressure wave and distance traveled as a pressure wire was withdrawn from the distal to the proximal coronary segment...
February 2, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28152457/numerical-investigations-of-flow-and-passive-pollutant-exposure-in-high-rise-deep-street-canyons-with-various-street-aspect-ratios-and-viaduct-settings
#16
Lejian He, Jian Hang, Xuemei Wang, Borong Lin, Xiaohui Li, Guangdong Lan
Vehicular pollutant exposure of residents and pedestrians in high-rise deep street canyons with viaducts and noise barriers requires special concerns because the ventilation capacity is weak and the literature reported inconsistent findings on flow patterns as aspect ratios (building height/street width, H/W) are larger than 2. By conducting computational fluid dynamics (CFD) simulations coupled with the intake fraction iF and the daily pollutant exposure Et, this paper investigates the impact of street aspect ratios, viaducts and noise barriers on the flow and vehicular passive pollutant exposure in full-scale street canyons (H/W=1-6, W=24m)...
April 15, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28151990/study-of-conformational-changes-and-protein-aggregation-of-bovine-serum-albumin-in-presence-of-sb-iii-and-sb-v
#17
Marcelo Verdugo, Jorge Ruiz Encinar, José Manuel Costa-Fernández, Mario Menendez-Miranda, Diego Bouzas-Ramos, Manuel Bravo, Waldo Quiroz
Antimony is a metalloid that affects biological functions in humans due to a mechanism still not understood. There is no doubt that the toxicity and physicochemical properties of Sb are strongly related with its chemical state. In this paper, the interaction between Sb(III) and Sb(V) with bovine serum albumin (BSA) was investigated in vitro by fluorescence spectroscopy, and circular dichroism (CD) under simulated physiological conditions. Moreover, the coupling of the separation technique, asymmetric flow field-flow fractionation, with elemental mass spectrometry to understand the interaction of Sb(V) and Sb(III) with the BSA was also used...
2017: PloS One
https://www.readbyqxmd.com/read/28147564/demisting-using-an-ultrasonic-standing-wave-field
#18
T M Merrell, J R Saylor
Removing drops from an air flow can be challenging, particularly, for small drops. Herein a method for demisting is presented that employs ultrasonics to force small drops to combine. Specifically, a cylindrical ultrasonic standing wave field is established in a tube, forming pressure nodes that take the form of cylinders located within the tube and having the same axis as the tube. Droplets are driven toward these pressure nodes by the acoustic radiation force, forcing smaller drops to combine to form larger drops, which eventually fall due to gravity, thereby demisting the flow...
January 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28125712/peptide-fractions-obtained-from-rice-by-products-by-means-of-an-environment-friendly-process-show-in-vitro-health-related-bioactivities
#19
Maura Ferri, Jürgen Graen-Heedfeld, Karlheinz Bretz, Fabien Guillon, Elisa Michelini, Maria Maddalena Calabretta, Matteo Lamborghini, Nicolò Gruarin, Aldo Roda, Axel Kraft, Annalisa Tassoni
Recently, the isolation of new health-related bioactive molecules derived from agro-food industrial by-products by means of environment-friendly extraction processes has become of particular interest. In the present study, a protein by-product from the rice starch industry was hydrolysed with five commercial proteolytic enzymes, avoiding the use of solvents or chemicals. The digestion processes were optimised, and the digestates were separated in fractions with four different molecular weight ranges by using a cross-flow membrane filtration technique...
2017: PloS One
https://www.readbyqxmd.com/read/28116495/field-flow-fractionation-techniques-to-explore-the-nano-world
#20
REVIEW
Catia Contado
Field flow fractionation (FFF) techniques are used to successfully characterize several nanomaterials by sizing nano-entities and producing information about the aggregation/agglomeration state of nanoparticles. By coupling FFF techniques to specific detectors, researchers can determine particle-size distributions (PSDs), expressed as mass-based or number-based PSDs. This review considers FFF applications in the food, biomedical, and environmental sectors, mostly drawn from the past 4 y. It thus underlines the prominent role of asymmetrical flow FFF within the FFF family...
April 2017: Analytical and Bioanalytical Chemistry
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