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32 results on '"Coelfen, H"'

1. Texture tomography, a versatile framework to study crystalline texture in 3D

Author

Frewein, M. P. K., Mason, J. K., Maier, B., Cölfen, H., Burghammer, M., Medjahed, A. A., Allain, M., and Grünewald, T. A.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Computational Physics
Abstract

The crystallographic texture is a key organization feature of many technical and biological materials. In these materials, especially hierarchically structured ones, the preferential alignment of the nano constituents is heavily influencing the macroscopic behaviour of the material. In order to study local crystallographic texture with both high spatial and angular resolution, we developed Texture tomography (TexTOM). This approach allows to model the diffraction data of polycrystalline materials by using the full reciprocal space of the ensemble of crystals and describe the texture in each voxel via a orientation distribution function. This means, it provides 3D reconstructions of the local texture by measuring the probabilities of all crystal orientations. The TexTOM approach addresses limitations associated with existing models: It correlates the intensities from several Bragg reflections, thus reduces ambiguities resulting from symmetry. Further, it yields quantitative probability distributions of local real space crystal orientations without further assumptions on the sample structure. Finally, its efficient mathematical formulation enables reconstructions faster than the time-scale of the experiment. In this manuscript, we present the mathematical model, the inversion strategy and its current experimental implementation. We show characterizations of simulated data as well as experimental data obtained from a synthetic, inorganic model sample, the silica-witherite biomorph. In conclusion, Tex-TOM provides a versatile framework to reconstruct 3D quantitative texture information for polycrystalline samples. In this way, it opens the door for unprecedented insights into the nanostructural makeup of natural and technical materials.

Published
2024

2. Size, Diffusion, and Sedimentation of Gold Nanorods

Author

Seibt, S, Pearson, J, Nixon-Luke, R, Zhang, H, Lang, PR, Bryant, G, Coelfen, H, Mulvaney, P, Seibt, S, Pearson, J, Nixon-Luke, R, Zhang, H, Lang, PR, Bryant, G, Coelfen, H, and Mulvaney, P

Abstract

We have used four different analytical techniques (electron microscopy (TEM), dynamic light scattering (DLS), analytical ultracentrifugation (AUC), and small angle X-ray scattering (SAXS) to measure the length and width as well as the diffusion coefficients of gold nanorods of different aspect ratio. All four methods could reproduce the trends in aspect ratio, and both length and width could be extracted once the ligand shell was accounted for. The CTAB bilayer coating was determined to have a thickness of 3.34, 3.02, and 3.26 nm by SAXS, DLS, and AUC, respectively. TEM nevertheless yielded the best predictions for the nanorod ensemble surface plasmon resonance by using COMSOL simulations. All four methods yielded better fits when the rods were treated as spherically capped cylinders.

Published
2023

23. A Multilaboratory Comparison of Calibration Accuracy and the Performance of External References in Analytical Ultracentrifugation

Author

Langowski, J, Zhao, H, Ghirlando, R, Alfonso, C, Arisaka, F, Attali, I, Bain, DL, Bakhtina, MM, Becker, DF, Bedwell, GJ, Bekdemir, A, Besong, TMD, Birck, C, Brautigam, CA, Brennerman, W, Byron, O, Bzowska, A, Chaires, JB, Chaton, CT, Coelfen, H, Connaghan, KD, Crowley, KA, Curth, U, Daviter, T, Dean, WL, Diez, AI, Ebel, C, Eckert, DM, Eisele, LE, Eisenstein, E, England, P, Escalante, C, Fagan, JA, Fairman, R, Finn, RM, Fischle, W, Garcia de la Torre, J, Gor, J, Gustafsson, H, Hall, D, Harding, SE, Hernandez Cifre, JG, Herr, AB, Howell, EE, Isaac, RS, Jao, S-C, Jose, D, Kim, S-J, Kokona, B, Kornblatt, JA, Kosek, D, Krayukhina, E, Krzizike, D, Kusznir, EA, Kwon, H, Larson, A, Laue, TM, Le Roy, A, Leech, AP, Lilie, H, Luger, K, Luque-Ortega, JR, Ma, J, May, CA, Maynard, EL, Modrak-Wojcik, A, Mok, Y-F, Muecke, N, Nagel-Steger, L, Narlikar, GJ, Noda, M, Nourse, A, Obsil, T, Park, CK, Park, J-K, Pawelek, PD, Perdue, EE, Perkins, SJ, Perugini, MA, Peterson, CL, Peverelli, MG, Piszczek, G, Prag, G, Prevelige, PE, Raynal, BDE, Rezabkova, L, Richter, K, Ringel, AE, Rosenberg, R, Rowe, AJ, Rufer, AC, Scott, DJ, Seravalli, JG, Solovyova, AS, Song, R, Staunton, D, Stoddard, C, Stott, K, Strauss, HM, Streicher, WW, Sumida, JP, Swygert, SG, Szczepanowski, RH, Tessmer, I, Toth, RT, Tripathy, A, Uchiyama, S, Uebel, SFW, Unzai, S, Gruber, AV, von Hippel, PH, Wandrey, C, Wang, S-H, Weitzel, SE, Wielgus-Kutrowska, B, Wolberger, C, Wolff, M, Wright, E, Wu, Y-S, Wubben, JM, Schuck, P, Langowski, J, Zhao, H, Ghirlando, R, Alfonso, C, Arisaka, F, Attali, I, Bain, DL, Bakhtina, MM, Becker, DF, Bedwell, GJ, Bekdemir, A, Besong, TMD, Birck, C, Brautigam, CA, Brennerman, W, Byron, O, Bzowska, A, Chaires, JB, Chaton, CT, Coelfen, H, Connaghan, KD, Crowley, KA, Curth, U, Daviter, T, Dean, WL, Diez, AI, Ebel, C, Eckert, DM, Eisele, LE, Eisenstein, E, England, P, Escalante, C, Fagan, JA, Fairman, R, Finn, RM, Fischle, W, Garcia de la Torre, J, Gor, J, Gustafsson, H, Hall, D, Harding, SE, Hernandez Cifre, JG, Herr, AB, Howell, EE, Isaac, RS, Jao, S-C, Jose, D, Kim, S-J, Kokona, B, Kornblatt, JA, Kosek, D, Krayukhina, E, Krzizike, D, Kusznir, EA, Kwon, H, Larson, A, Laue, TM, Le Roy, A, Leech, AP, Lilie, H, Luger, K, Luque-Ortega, JR, Ma, J, May, CA, Maynard, EL, Modrak-Wojcik, A, Mok, Y-F, Muecke, N, Nagel-Steger, L, Narlikar, GJ, Noda, M, Nourse, A, Obsil, T, Park, CK, Park, J-K, Pawelek, PD, Perdue, EE, Perkins, SJ, Perugini, MA, Peterson, CL, Peverelli, MG, Piszczek, G, Prag, G, Prevelige, PE, Raynal, BDE, Rezabkova, L, Richter, K, Ringel, AE, Rosenberg, R, Rowe, AJ, Rufer, AC, Scott, DJ, Seravalli, JG, Solovyova, AS, Song, R, Staunton, D, Stoddard, C, Stott, K, Strauss, HM, Streicher, WW, Sumida, JP, Swygert, SG, Szczepanowski, RH, Tessmer, I, Toth, RT, Tripathy, A, Uchiyama, S, Uebel, SFW, Unzai, S, Gruber, AV, von Hippel, PH, Wandrey, C, Wang, S-H, Weitzel, SE, Wielgus-Kutrowska, B, Wolberger, C, Wolff, M, Wright, E, Wu, Y-S, Wubben, JM, and Schuck, P

Abstract

Analytical ultracentrifugation (AUC) is a first principles based method to determine absolute sedimentation coefficients and buoyant molar masses of macromolecules and their complexes, reporting on their size and shape in free solution. The purpose of this multi-laboratory study was to establish the precision and accuracy of basic data dimensions in AUC and validate previously proposed calibration techniques. Three kits of AUC cell assemblies containing radial and temperature calibration tools and a bovine serum albumin (BSA) reference sample were shared among 67 laboratories, generating 129 comprehensive data sets. These allowed for an assessment of many parameters of instrument performance, including accuracy of the reported scan time after the start of centrifugation, the accuracy of the temperature calibration, and the accuracy of the radial magnification. The range of sedimentation coefficients obtained for BSA monomer in different instruments and using different optical systems was from 3.655 S to 4.949 S, with a mean and standard deviation of (4.304 ± 0.188) S (4.4%). After the combined application of correction factors derived from the external calibration references for elapsed time, scan velocity, temperature, and radial magnification, the range of s-values was reduced 7-fold with a mean of 4.325 S and a 6-fold reduced standard deviation of ± 0.030 S (0.7%). In addition, the large data set provided an opportunity to determine the instrument-to-instrument variation of the absolute radial positions reported in the scan files, the precision of photometric or refractometric signal magnitudes, and the precision of the calculated apparent molar mass of BSA monomer and the fraction of BSA dimers. These results highlight the necessity and effectiveness of independent calibration of basic AUC data dimensions for reliable quantitative studies.

Published
2015

26. Contributors

Author

An, J., Bigi, A., Boanini, E., Buchanan, F., Carrera, C.A., Cölfen, H., Combes, C., Cunningham, E., Douglas, Timothy E.L., Dunne, N., El-Fiqi, A., Gazzano, M., Giacaman, R.A., Gil Mur, F.J., Gower, L.B., Jansen, J., Kim, H.-W., Kokubo, T., Leeuwenburgh, S., Leonor, I.B., Navarro, M., Osorio, R., Perez, V.A., Rao, A., Reis, R.L., Rey, C., Rodrigues, A.I., Romero, P.A., Seo, S.-J., Serra, T., Seto, J., Toledano, M., Walker, G., Wolke, J., and Yamaguchi, S.

Published
2016
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