Sat, 26 Jul 2008 06:25:41 BST CiteULike: dchen's application http://www.citeulike.org/user/dchen/tag/application CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/2911387 <i>Soft Matter, 2008, 4, 919 - 924, DOI: 10.1039/b718441g</i><br /><br />An important challenge for colloid scientists is to design injectable dispersions that provide structural support for damaged soft tissue and enable regeneration of tissue over the longer term. In this article we highlight a new area of research that aims to produce pH-responsive microgel dispersions that restore the mechanical properties of damaged, load-bearing, soft tissue. Chronic back pain due to degeneration of the intervertebral disc (IVD) is a major health problem and is the primary potential application for the work discussed. pH-Responsive microgel dispersions contain cross-linked polymer particles that swell when the pH approaches the pKa of the incorporated ionic co-monomer. The work considered here involves microgel particles containing MAA (methacrylic acid). The particles show pronounced pH-triggered swelling. The concentrated microgel dispersions change from a fluid to a gel at pH values greater than ca. 6.2, which is within the physiological pH range. The rheological properties are pH-dependent and can be adjusted using particle composition or concentration. Degenerated IVDs containing injected, gelled, microgel dispersions show improved mechanical properties. The disc height under biomechanically meaningful loads can be restored to values observed in non-degenerated IVDs. We also discuss the steps required to provide a minimally invasive injectable microgel system for restoring both the IVD mechanical properties and regenerating tissue in vivo. The approach pH-Responsive microgel dispersions for repairing damaged load-bearing soft tissue Tony Freemont Brian Saunders Soft Matter, 2008, 4, 919 - 924, DOI: 10.1039/b718441g 2008-06-20T19:42:24-00:00 Soft Matter, 2008, 4, 919 - 924, DOI: 10.1039/b718441g 2008 application material microgel technique http://www.citeulike.org/user/dchen/article/2883928 <i>Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 75, No. 3. (2007)</i><br /><br />Granular mixtures immersed in a liquid (slurries) show segregation dynamics which are quantitatively and qualitatively different from those of dry systems. The principal mechanisms of the segregation dynamics in slurries, as well as the relevant material parameters that must be taken into account in a dynamic description are not sufficiently understood so far. We investigate experimentally the influence of the viscosity of the interstitial liquid on the coarsening of axial segregation patterns in a horizontally rotating mixer. It is found that not only the characteristic time scales but also fundamental structural features of these patterns are influenced by the viscous properties of the liquid component. Influences of the interstitial liquid on segregation patterns of granular slurries in a rotating drum Tilo Finger Ralf Stannarius doi:10.1103/PhysRevE.75.031308 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 75, No. 3. (2007) 2008-06-11T22:24:18-00:00 2007 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) 75 3 APS 2007 application grain pre segregation wetting http://www.citeulike.org/user/dchen/article/2883892 <i>Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 75, No. 2. (2007)</i><br /><br />We have characterized a montmorillonite-based organoclay dispersed in three different nonaqueous solvents using a combination of x-ray scattering, small-angle neutron scattering (SANS), and ultrasmall angle neutron scattering (USANS), together with rheological measurements. Consistent with these measurements, we present a structural model for the incompletely dispersed clay as consisting of randomly oriented tactoids made of partially overlapping clay sheets, with transverse dimensions of several microns. Intersheet correlation peaks are visible in x-ray scattering, and quantitatively fit by our model structure factor. SANS and USANS together show a power law of about −3 over a wide range of wave numbers below the intersheet correlation peak. Our model relates this power law to a power law distribution of the number of locally overlapping layers in a tactoid. The rheology data show that both storage and loss moduli, as well as yield stress, scale with a power law in volume fraction of about three. Equating the gel onset composition with the overlap of randomly oriented tactoids and taking into account the large transverse dimensions of the tactoids, we predict the gel point to be at or below 0.006 volume fraction organoclay. This is consistent with the rheology data. Structure and rheology of organoclay suspensions Jr Scott Milner Min Lin John Singh TG Mason doi:10.1103/PhysRevE.75.021403 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 75, No. 2. (2007) 2008-06-11T21:58:58-00:00 2007 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) 75 2 APS 2007 application mason pre rheology system http://www.citeulike.org/user/dchen/article/2882834 <i>Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 75, No. 5. (2007)</i><br /><br />In Al2O3 suspensions, depending on the experimental conditions, very different microstructures can be found, comprising fluidlike suspensions, a repulsive structure, and a clustered microstructure. For technical processing in ceramics, the knowledge of the microstructure is of importance, since it essentially determines the stability of a workpiece to be produced. To enlighten this topic, we investigate these suspensions under shear by means of simulations. We observe cluster formation on two different length scales: the distance of nearest neighbors and on the length scale of the system size. We find that the clustering behavior does not depend on the length scale of observation. If interparticle interactions are not attractive the particles form layers in the shear flow. The results are summarized in a stability diagram. Stability diagram for dense suspensions of model colloidal Al[sub 2]O[sub 3] particles in shear flow Martin Hecht Jens Harting Hans Herrmann doi:10.1103/PhysRevE.75.051404 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 75, No. 5. (2007) 2008-06-11T14:33:11-00:00 2007 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) 75 5 APS 2007 application flow material phase pre shear http://www.citeulike.org/user/dchen/article/2735360 <i>Nat Mater, Vol. 6, No. 12. (December 2007), pp. 921-922.</i> Colloids: A useful boundary Anthony Dinsmore doi:10.1038/nmat2062 Nat Mater, Vol. 6, No. 12. (December 2007), pp. 921-922. 2008-04-29T20:15:42-00:00 2007 Nat Mater 6 12 921 922 Nature Publishing Group application colloids nature http://www.citeulike.org/user/dchen/article/2730152 <i>Nat Mater, Vol. 4, No. 10. (October 2005), pp. 729-740.</i> Understanding foods as soft materials Raffaele Mezzenga Peter Schurtenberger Adam Burbidge Martin Michel doi:10.1038/nmat1496 Nat Mater, Vol. 4, No. 10. (October 2005), pp. 729-740. 2008-04-28T14:34:28-00:00 2005 Nat Mater 4 10 729 740 application nature review http://www.citeulike.org/user/dchen/article/2670772 <i>Nature, Vol. 367, No. 6463. (10 February 1994), pp. 541-543.</i> Deformation-induced nanocrystal formation in shear bands of amorphous alloys H Chen Y He GJ Shiflet SJ Poon doi:10.1038/367541a0 Nature, Vol. 367, No. 6463. (10 February 1994), pp. 541-543. 2008-04-14T22:43:53-00:00 1994 Nature 367 6463 541 543 application shear shearband