1,721,179 research outputs found
Estimation of Fractal Dimension of Colloidal Gels in the Presence of Multiple Scattering
No full textRationally designed Magnetic Particles enable Capturing and Detection of Bacterial Pathogens
No full textIn this work we highlight magnetic blood purification as possible therapy for blood stream infections [1-2], where circulating pathogens are at first removed from the bodily fluid and subsequently recovered and analyzed. (Fig. 1) This process would result in an immediate therapeutic benefit for the patient, while also considerably shortening the diagnosis process, a critical step which heavily affects the final outcome of the treatment. Finally, the use of a newly developed human IgG1 monoclonal antibody against poly-N-acetylglucosamine (PNAG) as targeting moiety extends this therapy to the majority of the pathogens responsible for the most frequent nosocomial infections. We show an experimental proof-of-concept study along with an optimization of carrier-pathogen interactions based on a mathematical model and an investigations on the process safety [3].
[1] I. K. Herrmann, M. Urner, F. M. Koehler, M. Hasler, B. Roth-Z’Graggen, R. N. Grass, U. Ziegler, B. Beck-Schimmer, and W. J. Stark, Small, 2010, 6, 1388
[2] I. K. Herrmann , M. Urner, S. Graf , C. M. Schumacher , B. Roth-Z’graggen , M. Hasler , W. J. Stark , and B. Beck-Schimmer, Adv. Healthcare Mater., 2013, 2, 829–835
[3] M. Lattuada, Q. Ren, F. Zuber, M. Galli, N. Bohmer, A. Wichser, S. Bertazzo, G. B. Pier and I. K. Herrmann, J. Mater Chem. B, under review
A simple model for the structure of fractal aggregates
No full textStructural properties of small aggregates containing up to 100 particles have been studied through detailed Monte Carlo cluster-cluster aggregation simulations in both diffusion-limited and reaction-limited conditions. First, the radius of gyration, the radius of the smallest sphere encompassing the cluster, and the particle-particle correlation function, g(r), have been computed based on the positions of all the particles in the cluster, and their fractal scaling has been analyzed. Then, an empirical model has been developed to simulate the g (r) function for aggregates of any size and used to determine the corresponding structural properties and scattering structure factors. Finally, in order to illustrate the application of the structural properties thus computed, two experiments on diffusion-limited aggregation have been performed, and the average scattering structure factors have been measured as a function of time using a small-angle light-scattering device. The obtained average scattering structure factors have been simulated using the Smoluchowski population balance equations, using the single aggregate structural properties and scattering structure factor predicted by the developed empirical g(r) model. (C) 2003 Elsevier Inc. All rights reserved
Hydrodynamic radius of fractal clusters
No full textThe Kirkwood-Riseman theory has been used to derive an analytical formula for the evaluation of the hydrodynamic radii of fractal clusters. The proposed relation is based on knowledge of the particle-particle correlation function and can be applied to clusters containing any number of particles larger than 4. The calculated values of the hydrodynamic radius are compared with the results of other theoretical approaches proposed in the literature, as well as several experimental data. Finally, the developed relation has been used in connection with a population balance equation model that computes the clusters' mass distribution to estimate the average hydrodynamic radius for a population of fractal clusters of different sizes. The obtained results have been compared to suitable experimental data for a silica colloidal suspension aggregating under reaction-limited conditions. (C) 2003 Elsevier Inc. All rights reserved
Effect of repulsive interactions on the rate of doublet formation of colloidal nanoparticles in the presence of convective transport.
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