Dynamic properties of colloidal suspensions of manganese ferrite particles

1997 ◽  
Vol 33 (5) ◽  
pp. 4251-4253 ◽  
Author(s):  
P.C. Fannin ◽  
S.W. Charles
Keyword(s):  
Dynamic Properties ◽  
Colloidal Suspensions ◽  
Manganese Ferrite

scholarly journals Multifunctional Properties of Binary Polyrhodanine Manganese Ferrite Nanohybrids—From the Energy Converters to Biological Activity

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2934
Author(s):  
Emilia Zachanowicz ◽  
Magdalena Kulpa-Greszta ◽  
Anna Tomaszewska ◽  
Małgorzata Gazińska ◽  
Monika Marędziak ◽  
...  
Keyword(s):  
Colloidal Suspensions ◽  
Specific Cell ◽  
Biological Interactions ◽  
Manganese Ferrite ◽  
Osteosarcoma Cells ◽  
Surface Protection ◽  
Biologically Relevant ◽  
Umr 106 ◽  
Relevant Range ◽  
And Staphylococcus Aureus

The PRHD@MnFe2O4 binary hybrids have shown a potential for applications in the biomedical field. The polymer cover/shell provides sufficient surface protection of magnetic nanoparticles against adverse effects on the biological systems, e.g., it protects against Fenton’s reactions and the generation of highly toxic radicals. The heating ability of the PRHD@MnFe2O4 was measured as a laser optical density (LOD) dependence either for powders as well as nanohybrid dispersions. Dry hybrids exposed to the action of NIR radiation (808 nm) can effectively convert energy into heat that led to the enormous temperature increase ΔT 170 °C (>190 °C). High concentrated colloidal suspensions (5 mg/mL) can generate ΔT of 42 °C (65 °C). Further optimization of the nanohybrids amount and laser parameters provides the possibility of temperature control within a biologically relevant range. Biological interactions of PRHD@MnFe2O4 hybrids were tested using three specific cell lines: macrophages (RAW 264.7), osteosarcoma cells line (UMR-106), and stromal progenitor cells of adipose tissue (ASCs). It was shown that the cell response was strongly dependent on hybrid concentration. Antimicrobial activity of the proposed composites against Escherichia coli and Staphylococcus aureus was confirmed, showing potential in the exploitation of the fabricated materials in this field.

scholarly journals Simultaneous light and small-angle neutron scattering on aggregating concentrated colloidal suspensions

2003 ◽  
Vol 36 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Sara Romer ◽  
Claus Urban ◽  
Vladimir Lobaskin ◽  
Frank Scheffold ◽  
Anna Stradner ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Dynamic Properties ◽  
Sol Gel ◽  
Colloidal Suspensions ◽  
Gel Point ◽  
Local Dynamic ◽  
Colloidal Systems ◽  
High Concentration

A new sample environment has been developed in order to perform light and small-angle neutron scattering (SANS) simultaneously on colloidal systems. The combination of SANS and diffusing wave spectroscopy (DWS) is of particular use in the high-concentration regime. DWS provides information on the local dynamic properties of the individual particles, whereas SANS gives access to the structural properties on similar length scales. The combination of both methods thus allows one to obtain structural and dynamic information over a very large range of length and time scales. Using this new setup, the onset of aggregation and the sol–gel transition in concentrated destabilized polystyrene sphere suspensions have been investigated. At the gel point, a dramatic change of the particle dynamics from diffusion to a subdiffusive arrested motion is observed. However, while the DWS measurements indicate that dramatic changes in the local dynamics occur over a long period, the SANS pattern quickly reaches its final appearance. The SANS experiments thus indicate that a fluid-like structure is arrested in the course of the gel formation. The data are found to be in good qualitative agreement with computer simulations.

Simulation Study of Structural and Dynamic Properties of Bi-Disperse Colloidal Suspensions

2020 ◽  
Vol 998 ◽  
pp. 283-289
Author(s):  
Danial Irfachsyad ◽  
Hira Meidia
Keyword(s):  
Dynamic Simulation ◽  
Simulation Study ◽  
Dynamic Properties ◽  
Colloidal Suspension ◽  
Colloidal Suspensions ◽  
Size Ratio ◽  
Brownian Dynamic ◽  
Small Particles ◽  
Soft Sphere ◽  
Disperse Particles

We used Brownian Dynamic simulation to study structural and dynamic properties of bi-disperse colloidal suspensions. The size ratio of large to small particles in the bi-disperse colloidal suspension is set at 5:1 and 10:1. We studied the interaction of aggregates (clusters) formed through DLVO (Derjaguin, Landau, Verwey and Overbeek) and soft sphere interactions in a bi-disperse suspension. The dynamic properties of bi-disperse is correlated by varying the size ratio of bi-disperse particles, it is found that the mobility is decreased at size ratio of large to small particles is 5:1. This is despite the percolating particle gels formation was disrupted by larger particles at higher size ratio.

scholarly journals Feasibility study of visibility-based X-ray photon correlation spectroscopy

2014 ◽  
Vol 70 (a1) ◽  
pp. C291-C291
Author(s):  
Ichiro Inoue ◽  
Yuya Shinohara ◽  
Akira Watanabe ◽  
Yoshiyuki Amemiya
Keyword(s):  
Time Resolution ◽  
Photon Correlation Spectroscopy ◽  
Dynamic Properties ◽  
Speckle Pattern ◽  
Colloidal Suspensions ◽  
Correlation Spectroscopy ◽  
Frame Rate ◽  
X Rays ◽  
Photon Correlation ◽  
X Ray

When coherent X-rays impinge upon a disordered system, a grainy scattering pattern called speckle pattern is observed. If the system evolves with time, the corresponding speckle pattern also changes. Temporal changes in the speckle patterns therefore provide information on the dynamics of the system. This technique, which is called X-ray photon correlation spectroscopy (XPCS) [1], has shown the potential to access dynamic properties of various materials, such as colloidal suspensions, block copolymer, supercooled liquids, alloys, and antiferromagnetic materials. Although XPCS is a powerful technique for material science as recent studies show, it has a limitation of time resolution: dynamics faster than the frame rate of detector cannot be measured. When a two-dimensional (2D) detector is used in XPCS, the time resolution is limited to the order of milliseconds. For improving the time resolution of XPCS, we have extended speckle visibility spectroscopy (SVS) in the region of visible light [2] to the region of X-rays (X-ray SVS; XSVS) [3]. Since the minimum exposure time of the scattering patterns determines the time resolutions of XSVS and SVS, micro- or nano- second dynamics can be measured even with a 2D detector. Thus, XSVS has potential to bridge the time gap between XPCS and inelastic neutron/X-ray scattering techniques, and will be one of the promising tools for various science with the next generation synchrotron X-ray sources, such as diffraction limited storage rings and energy recovery linac based X-ray sources. In this presentation, we will describe the principle of XSVS and show the result of the application of XSVS to Brownian colloidal suspensions. This study was performed under the approval of JASRI (2011A1112, 2011B1131). We acknowledge Drs. N. Yagi and N. Ohta for their kind support in performing experiments.

Dynamic properties of shear thickening colloidal suspensions

2003 ◽  
Vol 42 (3) ◽  
pp. 199-208 ◽  
Author(s):  
Young Sil Lee ◽  
Norman J. Wagner
Keyword(s):  
Dynamic Properties ◽  
Shear Thickening ◽  
Colloidal Suspensions

The distribution of antigen on the surface of RBL-2H3 rat basophilic leukemia cells observed by back-scattered electron imaging

1986 ◽  
Vol 44 ◽  
pp. 274-275
Author(s):  
R.F. Stump ◽  
J.R. Pfeiffer ◽  
JC. Seagrave ◽  
D. Huskisson ◽  
J.M. Oliver
Keyword(s):  
Cell Surface ◽  
Dynamic Properties ◽  
Leukemia Cells ◽  
Antigen Binding ◽  
Scattered Electron ◽  
Ige Receptor ◽  
Receptor Complexes ◽  
Rat Basophilic Leukemia Cells ◽  
Electron Imaging ◽  
Basophilic Leukemia

In RBL-2H3 rat basophilic leukemia cells, antigen binding to cell surface IgE-receptor complexes stimulates the release of inflammatory mediators and initiates a series of membrane and cytoskeletal events including a transformation of the cell surface from a microvillous to a lamellar topography. It is likely that dynamic properties of the IgE receptor contribute to the activation of these responses. Fewtrell and Metzger have established that limited crosslinking of IgE-receptor complexes is essential to trigger secretion. In addition, Baird and colleagues have reported that antigen binding causes a rapid immobilization of IgE-receptor complexes, and we have demonstrated an apparent increase with time in the affinity of IgE-receptor complexes for antigen.

A metal- coating Chamber for High-Resolution Cryo-SEM

1990 ◽  
Vol 48 (1) ◽  
pp. 418-419
Author(s):  
John G. Sheehan
Keyword(s):  
High Resolution ◽  
Colloidal Suspensions ◽  
Metal Coating ◽  
Colloidal Interactions ◽  
Amorphous Ice ◽  
High Vapor ◽  
Particulate Coatings ◽  
20 Nm ◽  
Film Nucleation ◽  
Coating Chamber

Improvements in particulate coatings for printable paper require understanding mechanisms of colloidal interactions in paper coating suspensions. One way to deduce colloidal interactions is to mage particle spacings and orientations at high resolution with cryo-SEM. Recent improvements in cryo-SEM technique have increased resolution enough to image particles in coating paints,vhich are sometimes smaller than 100 nm. In this report, a metal-coating chamber is described for preparation of colloidal suspensions for cryo-SEM at resolution down to 20 nm. It was found that etching is not necessary to achieve this resolution.A 120 K cryo-SEM sample will remain in an SEM for hours without noticeable condensation of imorphous ice. This is due to the high vapor pressure of vapor-condensed amorphous ice, measured by Kouchi. However, clean vacuum is required to coat samples with the thinnest possible continuous metal films which are required for high magnification SEM. Vapor contaminants, especially hrydrocarbons, are known to interfere with thin-film nucleation and growth so that more metal is needed to form continuous films, and resolution is decreased. That is why the metal-coating chamber in fig. 1 is designed for the cleanest possible vacuum. Feedthroughs for the manipulator md the shutter, which are operated during metal coating, are sealed with leak-proof stainless-steel Dellows. The transfer rod slides through a baseplate feedthrough that is double o-ring sealed.

Nucleosome dynamics

2006 ◽  
Vol 73 ◽  
pp. 109-119 ◽  
Author(s):  
Chris Stockdale ◽  
Michael Bruno ◽  
Helder Ferreira ◽  
Elisa Garcia-Wilson ◽  
Nicola Wiechens ◽  
...  
Keyword(s):  
High Resolution ◽  
Chromatin Structure ◽  
Current Knowledge ◽  
Dynamic Properties ◽  
Structure And Dynamics ◽  
Nucleosome Dynamics ◽  
Sharp Focus ◽  
Recent Advances ◽  
Insight Into ◽  
Chromatin Structure And Dynamics

In the 30 years since the discovery of the nucleosome, our picture of it has come into sharp focus. The recent high-resolution structures have provided a wealth of insight into the function of the nucleosome, but they are inherently static. Our current knowledge of how nucleosomes can be reconfigured dynamically is at a much earlier stage. Here, recent advances in the understanding of chromatin structure and dynamics are highlighted. The ways in which different modes of nucleosome reconfiguration are likely to influence each other are discussed, and some of the factors likely to regulate the dynamic properties of nucleosomes are considered.

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