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Artículos de revistas sobre el tema "Flow field flow fractionation (Fl-FFF)"

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Publicado: 22 de junio de 2024

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1

Kim, Suhan, Sungyun Lee, Chung-Hwan Kim y Jaeweon Cho. "A new membrane performance index using flow-field flow fractionation (fl-FFF)". Desalination 247, n.º 1-3 (octubre de 2009): 169–79. http://dx.doi.org/10.1016/j.desal.2008.12.022.

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2

Lim, Seongbeen, Sangyoup Lee, Soohoon Choi, Jihee Moon y Seungkwan Hong. "Evaluation of biofouling potential of microorganism using flow field-flow fractionation (Fl-FFF)". Desalination 264, n.º 3 (diciembre de 2010): 236–42. http://dx.doi.org/10.1016/j.desal.2010.05.042.

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3

Pellegrino, J., S. Wright, J. Ranvill y G. Amy. "Predicting membrane flux decline from complex mixtures using flow-field flow fractionation measurements and semi-empirical theory". Water Science and Technology 51, n.º 6-7 (1 de marzo de 2005): 85–92. http://dx.doi.org/10.2166/wst.2005.0625.

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Flow-Field Flow Fractionation (Fl-FFF) is an idealization of the cross flow membrane filtration process in that, (1) the filtration flux and crossflow velocity are constant from beginning to end of the device, (2) the process is a relatively well-defined laminar-flow hydrodynamic condition, and (3) the solutes are introduced as a pulse-input that spreads due to interactions with each other and the membrane in the dilute-solution limit. We have investigated the potential for relating Fl-FFF measurements to membrane fouling. An advection-dispersion transport model was used to provide ‘ideal’ (defined as spherical, non-interacting solutes) solute residence time distributions (RTDs) for comparison with ‘real’ RTDs obtained experimentally at different cross-field velocities and solution ionic strength. An RTD moment analysis based on a particle diameter probability density function was used to extract “effective” characteristic properties, rather than uniquely defined characteristics, of the standard solute mixture. A semi-empirical unsteady-state, flux decline model was developed that uses solute property parameters. Three modes of flux decline are included: (1) concentration polarization, (2) cake buildup, and (3) adsorption on/in pores, We have used this model to test the hypothesis—that an analysis of a residence time distribution using Fl-FFF can describe ‘effective’ solute properties or indices that can be related to membrane flux decline in crossflow membrane filtration. Constant flux filtration studies included the changes of transport hydrodynamics (solvent flux to solute back diffusion (J/k) ratios), solution ionic strength, and feed water composition for filtration using a regenerated cellulose ultrafiltration membrane. Tests of the modeling hypothesis were compared with experimental results from the filtration measurements using several correction parameters based on the mean and variance of the solute RTDs. The corrections used to modify the boundary layer mass transfer coefficient and the specific resistance of cake or adsorption layers demonstrated that RTD analysis is potentially useful technique to describe colloid properties but requires improvements.
4

Plavchak, Christine L., William C. Smith, Carmen R. M. Bria y S. Kim Ratanathanawongs Williams. "New Advances and Applications in Field-Flow Fractionation". Annual Review of Analytical Chemistry 14, n.º 1 (5 de junio de 2021): 257–79. http://dx.doi.org/10.1146/annurev-anchem-091520-052742.

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Field-flow fractionation (FFF) is a family of techniques that was created especially for separating and characterizing macromolecules, nanoparticles, and micrometer-sized analytes. It is coming of age as new nanomaterials, polymers, composites, and biohybrids with remarkable properties are introduced and new analytical challenges arise due to synthesis heterogeneities and the motivation to correlate analyte properties with observed performance. Appreciation of the complexity of biological, pharmaceutical, and food systems and the need to monitor multiple components across many size scales have also contributed to FFF's growth. This review highlights recent advances in FFF capabilities, instrumentation, and applications that feature the unique characteristics of different FFF techniques in determining a variety of information, such as averages and distributions in size, composition, shape, architecture, and microstructure and in investigating transformations and function.
5

Giordani, Stefano, Valentina Marassi, Anna Placci, Andrea Zattoni, Barbara Roda y Pierluigi Reschiglian. "Field-Flow Fractionation in Molecular Biology and Biotechnology". Molecules 28, n.º 17 (23 de agosto de 2023): 6201. http://dx.doi.org/10.3390/molecules28176201.

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Field-flow fractionation (FFF) is a family of single-phase separative techniques exploited to gently separate and characterize nano- and microsystems in suspension. These techniques cover an extremely wide dynamic range and are able to separate analytes in an interval between a few nm to 100 µm size-wise (over 15 orders of magnitude mass-wise). They are flexible in terms of mobile phase and can separate the analytes in native conditions, preserving their original structures/properties as much as possible. Molecular biology is the branch of biology that studies the molecular basis of biological activity, while biotechnology deals with the technological applications of biology. The areas where biotechnologies are required include industrial, agri-food, environmental, and pharmaceutical. Many species of biological interest belong to the operational range of FFF techniques, and their application to the analysis of such samples has steadily grown in the last 30 years. This work aims to summarize the main features, milestones, and results provided by the application of FFF in the field of molecular biology and biotechnology, with a focus on the years from 2000 to 2022. After a theoretical background overview of FFF and its methodologies, the results are reported based on the nature of the samples analyzed.
6

Remmo, Amani, Norbert Löwa, Julija Peter y Frank Wiekhorst. "Physical characterization of biomedical magnetic nanoparticles using multi-detector centrifugal field-flow fractionation". Current Directions in Biomedical Engineering 7, n.º 2 (1 de octubre de 2021): 327–30. http://dx.doi.org/10.1515/cdbme-2021-2083.

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Abstract The unique magnetic properties of magnetic nanoparticles (MNP) combined with their small size already led to numerous medical applications. Accurate determination of their magnetic properties is a key requirement enquired by users, that is impeded by the ever-present distribution of MNP sizes. Field flow fractionation (FFF) techniques may help to overcome these limitations by first separating the particles before characterization. In this study, we demonstrate the use of centrifugal FFF coupled to online detectors for fractionation, structural, and magnetic characterization of MNP. The primary goal is to establish a reproducible centrifugal FFF (CF3) method for MNP fractionation We show that CF3 has the same capability as other FFF techniques in resolving the bimodal hydrodynamic size distribution present in the commercial MNP system Resovist® but is faster and more straightforward through its technical approach.
7

Markx, Gerard H., Juliette Rousselet y Ronald Pethig. "DEP-FFF: Field-Flow Fractionation Using Non-Uniform Electric Fields". Journal of Liquid Chromatography & Related Technologies 20, n.º 16-17 (septiembre de 1997): 2857–72. http://dx.doi.org/10.1080/10826079708005597.

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8

Phelan Jr., Frederick R. y Barry J. Bauer. "Simulation of nanotube separation in field-flow fractionation (FFF)". Chemical Engineering Science 62, n.º 17 (septiembre de 2007): 4620–35. http://dx.doi.org/10.1016/j.ces.2007.04.019.

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9

Scherer, Christian, Sergey Noskov, Stefanie Utech, Christoph Bantz, Waltraut Mueller, Korinna Krohne y Michael Maskos. "Characterization of Polymer Nanoparticles by Asymmetrical Flow Field Flow Fractionation (AF-FFF)". Journal of Nanoscience and Nanotechnology 10, n.º 10 (1 de octubre de 2010): 6834–39. http://dx.doi.org/10.1166/jnn.2010.2973.

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10

Suwanpetch, Rabiab, Juwadee Shiowatana y Atitaya Siripinyanond. "Using flow field-flow fractionation (Fl-FFF) for observation of salinity effect on the size distribution of humic acid aggregates". International Journal of Environmental Analytical Chemistry 97, n.º 3 (19 de febrero de 2017): 217–29. http://dx.doi.org/10.1080/03067319.2017.1296141.

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11

Moon, Jihee, Jaeweon Cho y Do Hee Kim. "Identification of natural organic matter (NOM) transport behavior near the membrane surface using flow field-flow-fractionation (fl-FFF) micro channel". Journal of Water Supply: Research and Technology-Aqua 54, n.º 4 (junio de 2005): 249–59. http://dx.doi.org/10.2166/aqua.2005.0023.

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12

LEU, TZONG-SHYNG y CHIH-YUAN WENG. "DYNAMICS OF DIELECTROPHORETIC FIELD-FLOW FRACTIONATION (DEP-FFF) BASED MICRO SORTER FOR CELL SEPARATION". Modern Physics Letters B 23, n.º 03 (30 de enero de 2009): 389–92. http://dx.doi.org/10.1142/s0217984909018473.

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Dielectrophoretic Field-Flow Fractionation (DEP-FFF) is a technique that selects particles of interest from a mixture of many samples. Conventional DEP-FFF technique used DEP force to levitate particles to different heights according to their dielectric properties. Levitated particles are then separated by their velocity difference in a microchannel. Numerical simulation and experimental results found that particles become wavy trajectory when the ratio of levitation height (hp) and average of electrode width and spacing (d) is below 0.6 (hp/d<0.6). In the mean time, sorted particles disperse randomly in Y-direction, too. The wavy trajectory and random distribution cause cell separation imprecisely. A novel MEMS-fabricated DEP-FFF based micro sorters is designed to improve these problems. The experimental results show that the particles can be levitated to a constant height and focus into a single particle stream along the centerline in the new micro sorter design. One can conclude that the new design leads to better cell separation in a DEP-FFF based micro sorter.
13

SCHAUER, THADEUS. "Theoretical and practical aspects of the field-flow fractionation (FFF) method". Polimery 40, n.º 10 (octubre de 1995): 555–60. http://dx.doi.org/10.14314/polimery.1995.555.

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14

HIRAMATSU, Tsuyoshi, Satoshi OHNO, Yuta SAITO, Daichi TOGASHI, Satoshi OHNO y Seigou KAWAGUCHI. "Molecular Characterization of Water Soluble Polymers by Field-Flow Fractionation Multiangle Light Scattering FFF-MALS". KOBUNSHI RONBUNSHU 70, n.º 2 (2013): 72–81. http://dx.doi.org/10.1295/koron.70.72.

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15

Yin, Hai Yan, Chun Cheng Zuo y Hong Yan Shi. "Fabrication of Ultrasound-Gravity Field Flow Fractionation Devices Using Engraving Machine and Reliable Sealing Method". Advanced Materials Research 748 (agosto de 2013): 765–68. http://dx.doi.org/10.4028/www.scientific.net/amr.748.765.

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In this paper, based on a coupled ultrasound-gravity approach, we present a new method to separate micro nano-particles and introduce a rapid and easy method to fabricate field flow fractionation (FFF) devices. Furthermore, with an emphasis on the study of equipment engraving and sealing process, we optimize the parameters of processing.
16

Tan, Ping, Jingjing Yang y Volker Nischwitz. "A novel approach for determination of the dissolved and the particulate fractions in aqueous samples by flow field flow fractionation via online monitoring of both the cross flow and the detector flow using ICP-MS". Journal of Analytical Atomic Spectrometry 35, n.º 3 (2020): 548–59. http://dx.doi.org/10.1039/c9ja00313d.

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17

Fuentes, Catalina, In Kang, Jangjae Lee, Dongsup Song, Malin Sjöö, Jaeyeong Choi, Seungho Lee y Lars Nilsson. "Fractionation and characterization of starch granules using field-flow fractionation (FFF) and differential scanning calorimetry (DSC)". Analytical and Bioanalytical Chemistry 411, n.º 16 (8 de mayo de 2019): 3665–74. http://dx.doi.org/10.1007/s00216-019-01852-9.

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18

Ananieva, Irina A., Anastasia Yu Menshikova, Tatiana G. Evseeva y Josef Janča. "High-Speed Micro-Thermal Focusing Field-Flow Fractionation of Micron-Size Particles". Collection of Czechoslovak Chemical Communications 69, n.º 2 (2004): 322–29. http://dx.doi.org/10.1135/cccc20040322.

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Micron-size polystyrene-based latex particles were separated by using new micro-thermal field-flow fractionation (micro-TFFF). The order of retention from the largest to the smallest particles that appears at high field strength and high flow rate corresponds to the focusing mechanism which itself is a consequence of the lift forces acting on the particles. The mechanism of steric exclusion can only be effective at low flow rates of the carrier liquid. Whenever high-speed separation was performed, the focusing effect clearly dominated the FFF mechanism. This application of micro-TFFF in focusing mode to the separation of the particles is the first one published. As a result, micro-TFFF thus became a very universal technique for the separation of synthetic and natural macromolecules and of particles of various origin and size up to large (micron-size) diameter.
19

Borovina, Ante, Rafael E. Hincapie, Torsten Clemens, Eugen Hoffmann y Jonas Wegner. "Selecting EOR Polymers through Combined Approaches—A Case for Flooding in a Heterogenous Reservoir". Polymers 14, n.º 24 (16 de diciembre de 2022): 5514. http://dx.doi.org/10.3390/polym14245514.

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This work uses micromodel, core floods and Field-Flow Fractionation (FFF) evaluations to estimate the behaviour and key elements for selecting polymers to address heterogenous reservoirs. One of the approaches was to construct two-layered micromodels differing six times in permeability and based on the physical characteristics of a Bentheimer sandstone. Further, the impacts of injectivity and displacement efficiency of the chosen polymers were then assessed using single- and two-phase core tests. Moreover, FFF was also used to assess the polymers’ conformity, gyration radii, and molecular weight distribution. For the polymer selection for field application, we weighted on the good laboratory performance in terms of sweep efficiency improvement, injectivity, and propagation. Based on the results, polymer B (highest MWD) performed the poorest. Full spectrum MWD measurement using Field-Flow Fractionation is a key in understanding polymer behavior. Heterogenous micromodel evaluations provided consistent data to subsequent core flood evaluations and were in alignment with FFF indications. Single-phase core floods performed higher injection velocities (5 m/d) in combination of FFF showed that narrower MWD distribution polymers (polymers A and C) have less retention and better injectivity. Two-phase core floods performed at low, reservoir representative velocities (1 ft/d) showed that Polymer B could not be injected, with pressure response staying at high values even when chase brine is injected. Adsorption values for all tested polymers at these conditions were high, however highest were observed in the case of polymer B. Overall, for the polymer selection for field application, we weighted on the good laboratory performance in terms of sweep efficiency improvement, injectivity, polymer retention, and propagation; all accounted in this work.
20

Moon, Jihee y Jaeweon Cho. "Investigation of nano-colloid transport in UF membranes using flow field-flow fractionation (flow FFF) and an irreversible thermodynamic transport model". Desalination 179, n.º 1-3 (julio de 2005): 151–59. http://dx.doi.org/10.1016/j.desal.2004.11.063.

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21

Nischwitz, Volker, Nina Gottselig, Anna Missong, Thomas Meyn y Erwin Klumpp. "Field flow fractionation online with ICP-MS as novel approach for the quantification of fine particulate carbon in stream water samples and soil extracts". Journal of Analytical Atomic Spectrometry 31, n.º 9 (2016): 1858–68. http://dx.doi.org/10.1039/c6ja00027d.

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22

Levin, Shulamit. "Field-Flow Fractionation (FFF) and Related Techniques for the Separation of Particles, Colloids and Macromolecules". Israel Journal of Chemistry 30, n.º 3 (1990): 257–62. http://dx.doi.org/10.1002/ijch.199000026.

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23

Giddings, J. Calvin. "Micro-FFF: Theoretical and practical aspects of reducing the dimensions of field-flow fractionation channels". Journal of Microcolumn Separations 5, n.º 6 (noviembre de 1993): 497–503. http://dx.doi.org/10.1002/mcs.1220050602.

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24

Levin, Shulamit, Eytan Klausner y Shaul Muchtar. "Characterization of submicron MCT o/w emulsions using sedimentation field-flow fractionation (FFF) with power field programming". Journal of Pharmaceutical and Biomedical Analysis 12, n.º 9 (septiembre de 1994): 1115–21. http://dx.doi.org/10.1016/0731-7085(94)e0031-u.

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25

Choi, Jaeyeong, Hai Doo Kwen, Yeong Seok Kim, Seong Ho Choi y Seungho Lee. "γ-ray synthesis and size characterization of CdS quantum dot (QD) particles using flow and sedimentation field-flow fractionation (FFF)". Microchemical Journal 117 (noviembre de 2014): 34–39. http://dx.doi.org/10.1016/j.microc.2014.06.002.

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26

Mittal, Vikas. "Molecular Weight Distributions of Polymer Solutions: Combination of Field Flow Fractionation (FFF) and Analytical Ultracentrifugation (AUC)". Journal of Dispersion Science and Technology 33, n.º 5 (mayo de 2012): 631–38. http://dx.doi.org/10.1080/01932691.2011.579821.

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27

Лермонтов, А. С. y В. В. Родченкова. "Системы проточного фракционирования макромолекул и наночастиц в поперечных полях". ANALYTICS Russia 9, n.º 1 (25 de febrero de 2019): 76–82. http://dx.doi.org/10.22184/2227-572x.2019.09.1.76.82.

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Описан принцип действия аналитических систем на основе проточного фракционирования частиц в поперечных полях различной природы. Представлена история метода, механизмы проточного фракционирования в асимметричных потоках, электрическом и гравитационном полях, под действием центробежных сил, а также в условиях градиента температуры. Обсуждаются особенности и возможности, области применения и объекты исследования каждой модификации метода. Описано комплексное решение компании Postnova Analytics – платформа FFF (Field-Flow Fractionation) для проточного фракционирования частиц в поперечных полях, в которой интегрированы модули для разделения, детекторы, системы для стабилизации температуры и другие компоненты под единым программным управлением.
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Kamuri, Mohd, Zurina Zainal Abidin, Mohd Yaacob, Mohd Hamidon, Nurul Md Yunus y Suryani Kamarudin. "Separation and Detection of Escherichia coli and Saccharomyces cerevisiae Using a Microfluidic Device Integrated with an Optical Fibre". Biosensors 9, n.º 1 (14 de marzo de 2019): 40. http://dx.doi.org/10.3390/bios9010040.

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This paper describes the development of an integrated system using a dry film resistant (DFR) microfluidic channel consisting of pulsed field dielectrophoretic field-flow-fractionation (DEP-FFF) separation and optical detection. The prototype chip employs the pulse DEP-FFF concept to separate the cells (Escherichia coli and Saccharomyces cerevisiae) from a continuous flow, and the rate of release of the cells was measured. The separation experiments were conducted by changing the pulsing time over a pulsing time range of 2–24 s and a flow rate range of 1.2–9.6 μ L min − 1 . The frequency and voltage were set to a constant value of 1 M Hz and 14 V pk-pk, respectively. After cell sorting, the particles pass the optical fibre, and the incident light is scattered (or absorbed), thus, reducing the intensity of the transmitted light. The change in light level is measured by a spectrophotometer and recorded as an absorbance spectrum. The results revealed that, generally, the flow rate and pulsing time influenced the separation of E. coli and S. cerevisiae. It was found that E. coli had the highest rate of release, followed by S. cerevisiae. In this investigation, the developed integrated chip-in-a lab has enabled two microorganisms of different cell dielectric properties and particle size to be separated and subsequently detected using unique optical properties. Optimum separation between these two microorganisms could be obtained using a longer pulsing time of 12 s and a faster flow rate of 9.6 μ L min − 1 at a constant frequency, voltage, and a low conductivity.
29

Zhao, Y. y M. K. Sharp. "Finite Element Analysis of the Lift on a Slightly Deformable and Freely Rotating and Translating Cylinder in Two-Dimensional Channel Flow". Journal of Biomechanical Engineering 121, n.º 2 (1 de abril de 1999): 148–52. http://dx.doi.org/10.1115/1.2835096.

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Motivated by the lateral migration phenomena of fresh and glutaraldehyde-fixed red blood cells in a field flow fractionation (FFF) separation system, we studied the transverse hydrodynamic lift on a slightly flexible cylinder in a two-dimensional channel flow. The finite element method was used to analyze the flow field with the cylinder at different transverse locations in the channel. The shape of the cylinder was determined by the pressure on the surface of the cylinder from the flow field solution and by the internal elastic stress. The cylinder deformation and the flow field were solved simultaneously. The transverse lift exerted on the cylinder was then calculated. The axial and angular speed of the cylinder were iterated such that the drag and torque on the cylinder were nulled to represent a freely translating and rotating state. The results showed that the transverse lift on a deformable cylinder increased greatly and the equilibrium position moved closer to the center of the channel compared to a rigid cylinder. Also, with the same elastic modulus but a higher flow rate, a larger deformation and higher equilibrium location were found. The maximum deformation of the cylinder occurred when the cylinder was closest to the wall where a larger shear rate existed. The numerical results and experimental studies are discussed.
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Assemi, Shoeleh, Lei Pan, Xuming Wang, Titilayo Akinseye y Jan D. Miller. "Size Distribution, Elemental Composition and Morphology of Nanoparticles Separated from Respirable Coal Mine Dust". Minerals 13, n.º 1 (7 de enero de 2023): 97. http://dx.doi.org/10.3390/min13010097.

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Nanoparticles, defined as particles with one dimension below 100 nm, contribute little to the total mass concentration in respirable coal mine dust (RCMD) toxicological studies, but they could have a considerable part in the adverse health effects by RCMD inhalation. It has been shown that inhaled nanoparticles can penetrate deep into the lung and could plausibly contribute to acute and chronic pulmonary diseases by triggering oxidative stress formation and inducing inflammation. RCMD nanoparticles from samples collected in an underground mine in the United States were analyzed by a particle separation technique, field-flow fractionation (FFF), for size, morphology, and elemental composition. Two sub-techniques, asymmetrical flow field-flow fractionation (AsFlFFF), and sedimentation field-flow fractionation (SdFFF) were used to increase the detection size range. Nanoparticles with a size range between 25–400 nm were detected. Fractions were collected throughout the size distribution and were analyzed by electron microscopy and inductively-coupled plasma mass spectrometry (ICP-MS). Electron micrographs showed the presence of carbonaceous particles, mineral particles, diesel particles, and aggregates. Major and trace elements such as Si and Ca were detected in high abundance in all fractions. Other metals included Mg, Fe, Al, Cs, and Pb. Higher relative concentrations of Cs and Pb were observed at the size range below 30 nm. The data suggests that nanoparticles in RCMD can be highly reactive, either as a result of their size or their potential to carry toxins such as transition and heavy metals. To the best of the authors’ knowledge, this is the first data on the size, morphology, and composition of RCMD nanoparticles with a size below 100 nm.
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Marassi, Valentina, Stefano Giordani, Pierluigi Reschiglian, Barbara Roda y Andrea Zattoni. "Tracking Heme-Protein Interactions in Healthy and Pathological Human Serum in Native Conditions by Miniaturized FFF-Multidetection". Applied Sciences 12, n.º 13 (4 de julio de 2022): 6762. http://dx.doi.org/10.3390/app12136762.

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The interaction of heme with blood serum proteins plays an important role in many physiological and pathological processes involving enzyme activity, gene expression and cell proliferation. The mechanisms underlying these interactions are; however, not yet fully understood. New analytical methods able to investigate protein-heme binding in native, biologically representative conditions are thus required. In this work, we present a method based on miniaturized, hollow-fiber flow field-flow fractionation with multiple spectrophotometric and light-scattering detection for size separation of high-abundance serum proteins and selective detection of heme-bound subpopulations. Heme is found to mainly interact with serum albumin, whereas a low amount also binds to other proteins such as IgM. The ability to bind heme in physiological conditions is also investigated for individual serum proteins. IgG is found unable to bind heme at clinically relevant concentrations. The proposed method allows separation, quantitation, and mass/size characterization of serum high-abundance proteins, providing information of heme-protein complex stability and preferred heme-clearing pathways. The same approach could be in perspective extended to the investigation of specific heme-antibody binding, and to further studies involving other molecules of pharmaceutical/clinical interest.
32

Bao, Zhongli, Ya-Chi Cheng, Mary Ziping Luo y Jack Yongfeng Zhang. "Analysis of aggregation profile of glucagon using SEC-HPLC and FFF-MALS methods". PLOS ONE 19, n.º 5 (21 de mayo de 2024): e0304086. http://dx.doi.org/10.1371/journal.pone.0304086.

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Recently, the first generic glucagon for injection was approved for the treatment of severe hypoglycemia. Unlike its brand name recombinant glucagon, the generic glucagon is synthetic. Since glucagon has a high propensity to form aggregates in solution, it is essential to assess the aggregation profile of the synthetic glucagon compared to the recombinant glucagon. In this study, two robust separation methods, size-exclusion chromatography (SEC-HPLC) and field-flow fractionation coupled with a multi-angle light scattering detector (FFF-MALS), were employed to characterize generic and brand glucagon aggregation in six lots (three newly released, three expired). The presence of aggregation in samples was determined from the generated chromatograms and analyzed. The study showed that both products have comparable aggregation profiles. The SEC-HPLC demonstrated that in both glucagon versions, the expired lots had a higher percentage of dimers than the newly released lots, but even at expiration, the amount was negligible (∼0.1%). The FFF-MALS method did not detect any dimers or higher molecular weight aggregates. Further evaluation of the detection limit found that FFF-MALS was unable to detect aggregates at amounts lower than 0.5% of total glucagon. The negligible amounts of dimer detected in the generic and brand glucagon indicate that both versions are physically stable and are not prone to aggregation under clinically relevant conditions.
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Amarasiriwardena, Dula, Atitaya Siripinyanond y Ramon M. Barnes. "Trace elemental distribution in soil and compost-derived humic acid molecular fractions and colloidal organic matter in municipal wastewater by flow field-flow fractionation-inductively coupled plasma mass spectrometry (flow FFF-ICP-MS)". Journal of Analytical Atomic Spectrometry 16, n.º 9 (2001): 978–86. http://dx.doi.org/10.1039/b102625a.

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34

Marassi, Valentina, Ilaria Zanoni, Simona Ortelli, Stefano Giordani, Pierluigi Reschiglian, Barbara Roda, Andrea Zattoni et al. "Native Study of the Behaviour of Magnetite Nanoparticles for Hyperthermia Treatment during the Initial Moments of Intravenous Administration". Pharmaceutics 14, n.º 12 (15 de diciembre de 2022): 2810. http://dx.doi.org/10.3390/pharmaceutics14122810.

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Magnetic nanoparticles (MNPs) present outstanding properties making them suitable as therapeutic agents for hyperthermia treatments. Since the main safety concerns of MNPs are represented by their inherent instability in a biological medium, strategies to both achieve long-term stability and monitor hazardous MNP degradation are needed. We combined a dynamic approach relying on flow field flow fractionation (FFF)-multidetection with conventional techniques to explore frame-by-frame changes of MNPs injected in simulated biological medium, hypothesize the interaction mechanism they are subject to when surrounded by a saline, protein-rich environment, and understand their behaviour at the most critical point of intravenous administration. In the first moments of MNPs administration in the patient, MNPs change their surrounding from a favorable to an unfavorable medium, i.e., a complex biological fluid such as blood; the particles evolve from a synthetic identity to a biological identity, a transition that needs to be carefully monitored. The dynamic approach presented herein represents an optimal alternative to conventional batch techniques that can monitor only size, shape, surface charge, and aggregation phenomena as an averaged information, given that they cannot resolve different populations present in the sample and cannot give accurate information about the evolution or temporary instability of MNPs. The designed FFF method equipped with a multidetection system enabled the separation of the particle populations providing selective information on their morphological evolution and on nanoparticle–proteins interaction in the very first steps of infusion. Results showed that in a dynamic biological setting and following interaction with serum albumin, PP-MNPs retain their colloidal properties, supporting their safety profile for intravenous administration.
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Neal, Christopher, Sujita Sukumaran, Vishal Gupta, Insiya Jafferji, Dave Hasegawa, Vladislava O. Melnikova y Darren W. Davis. "Capture of EpCAM-negative and vimentin-positive circulating cancer cells (CCCs) from blood of metastatic breast cancer patients using ApoStream." Journal of Clinical Oncology 30, n.º 15_suppl (20 de mayo de 2012): e21029-e21029. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.e21029.

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e21029 Background: Up-regulation of epithelial mesenchymal transition (EMT) and the reduction of epithelial marker expression is associated with invasion, cancer progression, resistance to conventional therapies and poor prognosis. ApoStream, a novel continuous flow dielectrophoresis field-flow fractionation (DEP-FFF) device, was used to enable antibody-independent capture of circulating cancer cells (CCCs,also referred to as circulating tumor cells, CTC) for subsequent phenotyping of EMT markers. Methods: A side-by-side comparison of CellSearch and ApoStream was performed on 10 metastatic breast cancer patients. A multiplexed immunofluorescent assay and laser scanning cytometry analyses were used to unambiguously identify CK+/CD45–/DAPI+ CCCs and quantify their EpCAM and vimentin expression. Results: ApoStream recovered CK+/CD45–/DAPI+ CCCs from each breast cancer patient sample tested (mean=255 CCCs per 7.5 ml blood, see Table). ApoStream consistently recovered significantly higher number of CCCs compared to CellSearch (p=0.024). ApoStream recovered both EpCAM+ and EpCAM– CCCs in 50% and 90% of patients, respectively. Vimentin+ CCCs were isolated from 90% of patients. Conclusions: ApoStream’s higher capture efficiency demonstrated the majority of CCCs from breast cancer patients were EpCAM negative and vimentin-positive. ApoStream technology can be used to monitor CCCs undergoing EMT. [Table: see text]
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Zhao, Yu y M. Keith Sharp. "Stability of Elliptical Cylinders in Two-Dimensional Channel Flow". Journal of Biomechanical Engineering 122, n.º 5 (30 de mayo de 2000): 493–97. http://dx.doi.org/10.1115/1.1289990.

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The flow around rigid cylinders of elliptical cross section placed transverse to Poiseuille flow between parallel plates was simulated to investigate issues related to the tumbling of red blood cells and other particles of moderate aspect ratio in the similar flow in a Field Flow Fractionation (FFF) channel. The torque and transverse force on the cylinder were calculated with the cylinder freely translating, but prevented from rotating, in the flow. The aspect ratios (long axis to short axis) of the elliptical cylinders were 2, 3, 4, and 5. The cylinder was placed transversely at locations of y0/H=0.1, 0.2, 0.3, and 0.4, where y0 is the distance from the bottom of the channel and H is the height of the channel, and the orientation of the cylinder was varied from 0 to 10 deg with respect to the axis of the channel for a channel Reynolds number of 20. The results showed that equilibrium orientations (indicated by a zero net torque on the cylinder) were possible for high-aspect-ratio cylinders at transverse locations y0/H<0.2. Otherwise, the net torque on the cylinder was positive, indicating that the cylinder would rotate. For cylinders with a stable orientation, however, a transverse lift force existed up to about y0/H=0.25. Thus, a cylinder of neutral or low buoyancy might be lifted with a stable orientation from an initial position near the wall until it reached y0/H<0.2, whereupon it would begin to tumble or oscillate. The dependence of lift and torque on cylinder orientation suggested that neutral or low-buoyancy cylinders may oscillate in both transverse location and angular velocity. Cylinders more dense than the carrier fluid could be in equilibrium both in terms of orientation and transverse location if their sedimentation force matched their lift force for a location y0/H<0.2.[S0148-0731(00)00505-7]
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Ikeya, Takeshi, Kazunori Kataoka, Teruo Okano y Yasuhisa Sakurai. "Selective adhesion of rat lymphocyte subpopulation on the polymer surface with phenylboronic acid moieties: evaluation by field-flow fractionation/adhesion chromatography (FFF/AC) method". Reactive and Functional Polymers 37, n.º 1-3 (junio de 1998): 251–61. http://dx.doi.org/10.1016/s1381-5148(97)00136-3.

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38

Marassi, Valentina, Stefano Giordani, Anna Placci, Angela Punzo, Cristiana Caliceti, Andrea Zattoni, Pierluigi Reschiglian, Barbara Roda y Aldo Roda. "Emerging Microfluidic Tools for Simultaneous Exosomes and Cargo Biosensing in Liquid Biopsy: New Integrated Miniaturized FFF-Assisted Approach for Colon Cancer Diagnosis". Sensors 23, n.º 23 (27 de noviembre de 2023): 9432. http://dx.doi.org/10.3390/s23239432.

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The early-stage diagnosis of cancer is a crucial clinical need. The inadequacies of surgery tissue biopsy have prompted a transition to a less invasive profiling of molecular biomarkers from biofluids, known as liquid biopsy. Exosomes are phospholipid bilayer vesicles present in many biofluids with a biologically active cargo, being responsible for cell-to-cell communication in biological systems. An increase in their excretion and changes in their cargo are potential diagnostic biomarkers for an array of diseases, including cancer, and they constitute a promising analyte for liquid biopsy. The number of exosomes released, the morphological properties, the membrane composition, and their content are highly related to the physiological and pathological states. The main analytical challenge to establishing liquid biopsy in clinical practice is the development of biosensors able to detect intact exosomes concentration and simultaneously analyze specific membrane biomarkers and those contained in their cargo. Before analysis, exosomes also need to be isolated from biological fluids. Microfluidic systems can address several issues present in conventional methods (i.e., ultracentrifugation, size-exclusion chromatography, ultrafiltration, and immunoaffinity capture), which are time-consuming and require a relatively high amount of sample; in addition, they can be easily integrated with biosensing systems. A critical review of emerging microfluidic-based devices for integrated biosensing approaches and following the major analytical need for accurate diagnostics is presented here. The design of a new miniaturized biosensing system is also reported. A device based on hollow-fiber flow field-flow fractionation followed by luminescence-based immunoassay is applied to isolate intact exosomes and characterize their cargo as a proof of concept for colon cancer diagnosis.
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Poklepovic, Andrew Stewart, Wen Wan, Weiguo Wu, Jacky Woo, Vladislava Melnikova, Elena Jouravleva, Kenna Lynn Anderes y Darren Davis. "ApoStream, an antibody-independent platform, compared to CellSearch for enumeration of circulating tumor cells (CTCs) in patients with metastatic prostate cancer." Journal of Clinical Oncology 30, n.º 15_suppl (20 de mayo de 2012): e21058-e21058. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.e21058.

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e21058 Background: Development of CTC detection platforms is a rapidly advancing field. The CellSearch technique relies on cell surface expression of EpCAM to select for rare tumor cells in whole blood specimens. Consequently, the use of EpCAM-based enrichment platforms to recover CTCs is limited to EpCAM expressing cells and is poorly suited for recovery of EpCAM negative cells like those having undergone epithelial mesenchymal transition (EMT). ApoStream is an antibody independent enrichment platform which utilizes the principle of continuous flow dielectrophoresis field-flow fractionation (DEP-FFF) to isolate and enrich for CTCs. A head to head comparison of CellSearch to ApoStream for recovery of CTCs in patients with metastatic prostate cancer was performed. Methods: Two 7.5 mL bloodsamples were collected at a single time point for each patient with stage IV prostate cancer. One sample was analyzed by CellSearch CTC enumeration kit, and one sample was analyzed by ApoStream. CTCs recovered by both devices were immunophenotyped using antibodies against cytokeratin (CK), CD45 and DAPI. CTCs were defined as CK+/CD45-/DAPI+ intact cells. CTCs recovered by ApoStream were further analyzed by quantitative laser scanning cytometry (LSC). A paired t-test was used to compare the cell counts in the two devices. Results: The ApoStream CTC enrichment platform isolated a greater number of CTCs from blood of eight patients compared to CellSearch (p= 0.0027). All cell counts obtained by the ApoStream technique were higher than CellSearch, and all patients had detectable CTCs by ApoStream, while only 75% of patients had detectable CTCs with CellSearch. Conclusions: The ApoStream platform is differentiated from EpCAM dependent platforms and is well suited for detection and recovery of CTCs in advanced stage disease where tumor cell heterogeneity is common and expression of EpCAM may be low or lost. [Table: see text]
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Scheurer, Christian, Rafael E. Hincapie, Elisabeth Neubauer, Astrid Metz y Daniel Ness. "Sorption of Nanomaterials to Sandstone Rock". Nanomaterials 12, n.º 2 (7 de enero de 2022): 200. http://dx.doi.org/10.3390/nano12020200.

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We investigated the interaction of silica nanostructured particles and sandstone rock using various experimental approaches, such as fluid compatibility, batch sorption and single-phase core-floods. Diol and polyethylenglycol (PEG) surface-modified nanostructured silica materials were tested using two brines differing in ionic strength and with the addition of sodium carbonate (Na2CO3). Berea and Keuper outcrop materials (core plug and crushed samples) were used. Core-flood effluents were analysed to define changes in concentration and a rock’s retention compared to a tracer. Field Flow Fractionation (FFF) and Dynamic Light Scattering (DLS) were performed to investigate changes in the effluent’s size distribution. Adsorption was evaluated using UV–visible spectroscopy and scanning electron microscopy (SEM). The highest adsorption was observed in brine with high ionic strength, whereas the use of alkali reduced the adsorption. The crushed material from Berea rock showed slightly higher adsorption compared to Keuper rock, whereas temperature had a minor effect on adsorption behaviour. In core-flood experiments, no effects on permeability have been observed. The used particles showed a delayed breakthrough compared to the tracer, and bigger particles passed the rock core faster. Nanoparticle recovery was significantly lower for PEG-modified nanomaterials in Berea compared to diol-modified nanomaterials, suggesting high adsorption. SEM images indicate that adsorption spots are defined via surface roughness rather than mineral type. Despite an excess of nanomaterials in the porous medium, monolayer adsorption was the prevailing type observed.
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Shin, Kayeong, Jaeyeong Choi, Yeoju Kim, Yoonjeong Lee, Joohoon Kim, Seungho Lee y Hoeil Chung. "Feasibility study for combination of field-flow fractionation (FFF)-based separation of size-coded particle probes with amplified surface enhanced Raman scattering (SERS) tagging for simultaneous detection of multiple miRNAs". Journal of Chromatography A 1556 (junio de 2018): 97–102. http://dx.doi.org/10.1016/j.chroma.2018.04.057.

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42

Gupta, Vishal, Insiya Jafferji, Miguel Garza, Sujita Sukumaran, Jacky Woo, Dave Hasegawa, Vladislava O. Melnikova y Darren W. Davis. "ApoStream, a novel device for antibody-independent capture of circulating cancercells (CCCs) from blood of patients with various types of cancer." Journal of Clinical Oncology 30, n.º 15_suppl (20 de mayo de 2012): e13500-e13500. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.e13500.

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e13500 Background: The detection of circulating tumor cells (CTCs) using immunomagnetic EpCAM-based capture methods has been conceptually accepted as a “liquid tumor biopsy”. However, these methods have limited the recovery of CTCs for molecular profiling applications. We developed a novel continuous flow dielectrophoresis field-flow fractionation (DEP-FFF) device, ApoStream for antibody-independent capture of circulating cancer cells (CCCs), with improved recovery across multiple cancer types and preserved viability of CCCs for downstream characterization. Methods: The performance of ApoStream was demonstrated using a low EpCAM expressing cell line, SKOV3. ApoStream was further used to enrich CCCs from various cancer patient blood. Prostate, breast and NSCLC CCCs were stained for cytokeratin (CK), CD45, and DAPI; melanoma CCCs were stained with S100, CD45 and DAPI. CCC enumeration was performed using laser scanning cytometry. Results: In system precision performance studies, average inter-day recovery on the ApoStream was 80.3 ± 3.5%, CV = 4.3% when cancer cells were spiked into buffer, and 78.5 ± 3.0%, CV = 3.3% when cancer cells spiked into ~10 million healthy peripheral blood mononuclear cells (PBMCs). Linearity performance was demonstrated with spiking 5-2600 SKOV3 cells into 10 million PBMCs (R2=1). Cell viability was not affected by processing through ApoStream device. High CCC recovery from metastatic cancer patient blood samples was obtained with counts ranging from 0 - 2630 (NSCLC, n=66), 0 - 3490 (prostate, n=29), 10 - 968 (breast, n=11), and 3 - 3120 (melanoma, n=13) CCCs per 7.5 mL blood. Positive CCC counts were obtained in 90% of NSCLC samples, 93% of prostate cancer samples, 100% breast cancer and melanoma specimens. There were no CK+ cells detected in healthy donor blood controls. Conclusions: Improved CCC recovery from various cancer types was demonstrated with the ApoStream device. ApoStream provides an antibody-independent method for capture of viable CCCs that enables further downstream molecular characterization of rare cells for use in clinical applications. Acknowledgements: Funded by NCI Contract No. HHSN261200800001E.
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Radnik, Jörg, Vasile-Dan Hodoroaba, Harald Jungnickel, Jutta Tentschert, Andreas Luch, Vanessa Sogne, Florian Meier et al. "Automation and Standardization—A Coupled Approach towards Reproducible Sample Preparation Protocols for Nanomaterial Analysis". Molecules 27, n.º 3 (1 de febrero de 2022): 985. http://dx.doi.org/10.3390/molecules27030985.

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Whereas the characterization of nanomaterials using different analytical techniques is often highly automated and standardized, the sample preparation that precedes it causes a bottleneck in nanomaterial analysis as it is performed manually. Usually, this pretreatment depends on the skills and experience of the analysts. Furthermore, adequate reporting of the sample preparation is often missing. In this overview, some solutions for techniques widely used in nano-analytics to overcome this problem are discussed. Two examples of sample preparation optimization by automation are presented, which demonstrate that this approach is leading to increased analytical confidence. Our first example is motivated by the need to exclude human bias and focuses on the development of automation in sample introduction. To this end, a robotic system has been developed, which can prepare stable and homogeneous nanomaterial suspensions amenable to a variety of well-established analytical methods, such as dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), field-flow fractionation (FFF) or single-particle inductively coupled mass spectrometry (sp-ICP-MS). Our second example addresses biological samples, such as cells exposed to nanomaterials, which are still challenging for reliable analysis. An air–liquid interface has been developed for the exposure of biological samples to nanomaterial-containing aerosols. The system exposes transmission electron microscopy (TEM) grids under reproducible conditions, whilst also allowing characterization of aerosol composition with mass spectrometry. Such an approach enables correlative measurements combining biological with physicochemical analysis. These case studies demonstrate that standardization and automation of sample preparation setups, combined with appropriate measurement processes and data reduction are crucial steps towards more reliable and reproducible data.
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Poklepovic, A., D. Davis, V. Melnikova y K. Anderes. "439 Comparison of Dielectrophoretic Field Flow Fractionation (DEP-FFF) with ApoStream™, an Antibody Independent Platform, with Immunomagnetic Capture Using CellSearch™ for Enumeration of Circulating Tumor Cells in Patients with Metastatic Prostate Cancer". European Journal of Cancer 48 (noviembre de 2012): 136. http://dx.doi.org/10.1016/s0959-8049(12)72237-2.

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Jestadi Ragaswetha, V. Nikhila, B. Lakshmi Kalyani, M. Adarsh, Varsha Padhi y N. Avinash. "Review : Field Flow Fractionation". International Journal of Advanced Research in Science, Communication and Technology, 21 de mayo de 2024, 684–91. http://dx.doi.org/10.48175/ijarsct-18373.

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Field flow Fractionation is a technique which is used for the separation of colloidal or high molecular weight substances in liquid solution, flowing through the separation platform, which does not have a stationary phase. It is similar to liquid chromatography, as it works on dilute solutions or suspensions of the solute, carried by a flowing eluent.separation is done by applying a fields like hydraulic, centrifugal, thermal, electrical, magnetic, gravitational or cross flowing, perpendicular to the direction of the sample .Field flow fractionation (FFF) is a chromatography-like separation technique used to separate macromolecules, colloids, and particles. The idea is straightforward. A parabolic velocity profile is created by a laminar flow of carrier liquid between two walls separated by approximately 0.1 mm
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Steindl, Johannes, Rafael E. Hincapie, Ante Borovina, Christoph Puls, Johann Badstoeber, Gerhard Heinzmann y Torsten Clemens. "Improved Enhanced Oil Recovery Polymer Selection Using Field-Flow Fractionation". SPE Reservoir Evaluation & Engineering, 1 de febrero de 2022, 1–12. http://dx.doi.org/10.2118/207700-pa.

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Summary Various polyacrylamide polymers have been successfully applied in chemical enhanced oil recovery (EOR) projects. These polymers are characterized by high molecular weights (MWs) to achieve high viscosifying power. The selection of polymers for chemical EOR is a crucial step in the field testing and implementation of such EOR projects. The reason is that per-pattern operating expenditures (OPEX) are one of the sensitive cost drivers for such projects. The important parameters for the selection of polymers are the filtration ratio, viscosifying power, polymer retention, and stability of the polymers at reservoir conditions. The MW distribution (MWD) of the polymers has a major impact on polymer properties and performance. Measuring the MWD is challenging using conventional methods. Field-flow fractionation (FFF) enables the determination of the distribution to select and quality check various polymers. Multiangle light scattering (MALS) was used as the main detector. Polymers with high MWs (&gt;1 MDa) are used for EOR to obtain highly viscous aqueous solutions. The MWD of the polymers is crucial for the solution characteristics. Conventional analysis of polymers is performed using either viscometry, which is able to determine the average MW but does not give information on MWD, or size-exclusion chromatography (SEC), which is restricted to MWs of &lt;20 MDa. FFF is based on the analytes flowing at different speeds in a channel-dependent on their size and mass. This effect leads to separation, which is then used to determine the MWD. FFF allows determining the MW and MWD of various ultrahigh MW polyacrylamides (HPAAMs). The FFF measurements showed that, despite similar MWs being claimed, substantial differences in MWD are observed. This technology allowed the quantification of the MWD of HPAAMs up to an MW of 5 GDa. Furthermore, gyration radii of the HPAAM molecules were determined. Selecting polymers on viscosifying power only is not addressing issues related to different MWs and MWDs such as selective polymer retention and degradation of the high molar mass part of the distribution. The results were used to improve the polymer selection for chemical EOR projects. In addition to viscosifying power and price, also the MWD and changes of the MWD in the porous medium are considered in the selection of the polymer. Overall, this work presents a new technique for the analysis of ultrahigh MW EOR polymers, which enables the possibility to determine the full range of polymer MWDs. This available information enhances the EOR polymer selection process addressing selective polymer retention and mechanical degradation in addition to the viscosifying power of polymers.
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Walker, Joshua, Syampriya Bindhu Syammohan y Zahra Rattray. "The Application of Field-Flow Fractionation to the Analysis of Nanomedicines". British Journal of Pharmacy, 30 de junio de 2022. http://dx.doi.org/10.5920/bjpharm.1132.

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Thecombination of field-flow fractionation with powerful leading-edge detectors canbe applied to the measurement of nanomaterial physicochemical properties, and thecreation of harmonized robust measurement protocols. The Multiscale MetrologySuite (MMS) at the University of Strathclyde is a unique internationallyleading facility combining multiple leading-edge field flow fractionation modalities(electric, asymmetric and centrifugal) with in-line Raman, inductively-coupledplasma (ICP) mass spectrometry and multimodal detector capability. Using exemplarcase studies, we demonstrate the application of various FFF hyphenations forthe analysis of a diverse materials portfolio. One of the goals for the MMS isto raise the standards of traditional academic analytical support underpinningpioneering academic engineering, physical and life sciences research exploringnovel materials as diagnostics and therapeutics.
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Williams, Kim, Ilyong Park, Edward E. Remsen y Mansour Moinpour. "New Particle Metrology for CMP Slurries". MRS Proceedings 991 (2007). http://dx.doi.org/10.1557/proc-0991-c09-01.

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ABSTRACTA new particle sizing and counting method based on the coupling of flow field-flow fractionation (FFF) with dual-sensor, single particle optical sensing (SPOS) detection is reported. The integration of FFF and SPOS systems was accomplished by means of a dilution interface that preserved the resolution of FFF-separated particles. Analysis of a model mixture of polystyrene latex standards of different diameters established that the FFF-SPOS system can resolve particles into discrete peaks for subsequent particle counting. Application of this method for the analysis of a colloidal silica standard demonstrated its use for materials commonly employed as CMP abrasives. Further development and refinement of the technique will enable compositional and structural analyses of heterogeneous large particle populations constituting commercial CMP slurries.
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Marassi, Valentina, Monica Mattarozzi, Lorenzo Toma, Stefano Giordani, Luca Ronda, Barbara Roda, Andrea Zattoni, Pierluigi Reschiglian y Maria Careri. "FFF-based high-throughput sequence shortlisting to support the development of aptamer-based analytical strategies". Analytical and Bioanalytical Chemistry, 18 de febrero de 2022. http://dx.doi.org/10.1007/s00216-022-03971-2.

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AbstractAptamers are biomimetic receptors that are increasingly exploited for the development of optical and electrochemical aptasensors. They are selected in vitro by the SELEX (Systematic Evolution of Ligands by Exponential Enrichment) procedure, but although they are promising recognition elements, for their reliable applicability for analytical purposes, one cannot ignore sample components that cause matrix effects. This particularly applies when different SELEX-selected aptamers and related truncated sequences are available for a certain target, and the choice of the aptamer should be driven by the specific downstream application. In this context, the present work aimed at investigating the potentialities of asymmetrical flow field-flow fractionation (AF4) with UV detection for the development of a screening method of a large number of anti-lysozyme aptamers towards lysozyme, including randomized sequences and an interfering agent (serum albumin). The possibility to work in native conditions and selectively monitor the evolution of untagged aptamer signal as a result of aptamer-protein binding makes the devised method effective as a strategy for shortlisting the most promising aptamers both in terms of affinity and in terms of selectivity, to support subsequent development of aptamer-based analytical devices. Graphical abstract
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Huber, Maximilian J., Natalia P. Ivleva, Andy M. Booth, Irina Beer, Ivana Bianchi, Roland Drexel, Otmar Geiss et al. "Physicochemical characterization and quantification of nanoplastics: applicability, limitations and complementarity of batch and fractionation methods". Analytical and Bioanalytical Chemistry, 27 de abril de 2023. http://dx.doi.org/10.1007/s00216-023-04689-5.

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Abstract A comprehensive physicochemical characterization of heterogeneous nanoplastic (NPL) samples remains an analytical challenge requiring a combination of orthogonal measurement techniques to improve the accuracy and robustness of the results. Here, batch methods, including dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), tunable resistive pulse sensing (TRPS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), as well as separation/fractionation methods such as centrifugal liquid sedimentation (CLS) and field-flow fractionation (FFF)–multi-angle light scattering (MALS) combined with pyrolysis gas chromatography mass spectrometry (pyGC–MS) or Raman microspectroscopy (RM) were evaluated for NPL size, shape, and chemical composition measurements and for quantification. A set of representative/test particles of different chemical natures, including (i) polydisperse polyethylene (PE), (ii) (doped) polystyrene (PS) NPLs, (iii) titanium dioxide, and (iv) iron oxide nanoparticles (spherical and elongated), was used to assess the applicability and limitations of the selected methodologies. Particle sizes and number-based concentrations obtained by orthogonal batch methods (DLS, NTA, TRPS) were comparable for monodisperse spherical samples, while higher deviations were observed for polydisperse, agglomerated samples and for non-spherical particles, especially for light scattering methods. CLS and TRPS offer further insight with increased size resolution, while detailed morphological information can be derived by electron microscopy (EM)–based approaches. Combined techniques such as FFF coupled to MALS and RM can provide complementary information on physical and chemical properties by online measurements, while pyGC–MS analysis of FFF fractions can be used for the identification of polymer particles (vs. inorganic particles) and for their offline (semi)quantification. However, NPL analysis in complex samples will continue to present a serious challenge for the evaluated techniques without significant improvements in sample preparation. Graphical abstract

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