1
|
Grieb T, Krause FF, Mehrtens T, Mahr C, Gerken B, Schowalter M, Freitag B, Rosenauer A. GaN atomic electric fields from a segmented STEM detector: Experiment and simulation. J Microsc 2024. [PMID: 38372408 DOI: 10.1111/jmi.13276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 01/31/2024] [Indexed: 02/20/2024]
Abstract
Atomic electric fields in a thin GaN sample are measured with the centre-of-mass approach in 4D-scanning transmission electron microscopy (4D-STEM) using a 12-segmented STEM detector in a Spectra 300 microscope. The electric fields, charge density and potential are compared to simulations and an experimental measurement using a pixelated 4D-STEM detector. The segmented detector benefits from a high recording speed, which enables measurements at low radiation doses. However, there is measurement uncertainty due to the limited number of segments analysed in this study.
Collapse
Affiliation(s)
- Tim Grieb
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Florian F Krause
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Thorsten Mehrtens
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Christoph Mahr
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Beeke Gerken
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Marco Schowalter
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| | - Bert Freitag
- Thermo Fisher Scientific, Eindhoven, The Netherlands
| | - Andreas Rosenauer
- Institute of Solid State Physics, University of Bremen, Bremen, Germany
| |
Collapse
|
2
|
Leich E, Brodtkorb M, Schmidt T, Altenbuchinger M, Lingjærde OC, Lockmer S, Holte H, Nedeva T, Grieb T, Sander B, Sundström C, Spang R, Kimby E, Rosenwald A. Gene expression and copy number profiling of follicular lymphoma biopsies from patients treated with first-line rituximab without chemotherapy. Leuk Lymphoma 2023; 64:1927-1937. [PMID: 37683053 DOI: 10.1080/10428194.2023.2240462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 07/12/2023] [Accepted: 07/18/2023] [Indexed: 09/10/2023]
Abstract
The Nordic Lymphoma Study Group has performed two randomized clinical trials with chemotherapy-free first-line treatment (rituximab +/- interferon) in follicular lymphoma (FL), with 73% of patients alive and 38% without any need of chemotherapy after 10.6 years median follow-up. In order to identify predictive markers, that may also serve as therapeutic targets, gene expression- and copy number profiles were obtained from 97 FL patients using whole genome microarrays. Copy number alterations (CNAs) were identified, e.g. by GISTIC. Cox Lasso Regression and Lasso logistic regression were used to determine molecular features predictive of time to next therapy (TTNT). A few molecular changes were associated with TTNT (e.g. increased expression of INPP5B, gains in 12q23/q24), but were not significant after adjusting for multiple testing. Our findings suggest that there are no strong determinants of patient outcome with respect to GE data and CNAs in FL patients treated with a chemotherapy-free regimen (i.e. rituximab +/- interferon).
Collapse
Affiliation(s)
- E Leich
- Institute of Pathology, University of Würzburg, Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | | | - T Schmidt
- Statistical Bioinformatics, Institute of Functional Genomics, University of Regensburg, Regensburg, Germany
| | - M Altenbuchinger
- Statistical Bioinformatics, Institute of Functional Genomics, University of Regensburg, Regensburg, Germany
- Department of Medical Bioinformatics, University Medical Center Göttingen, Göttingen, Germany
| | - Ole Christian Lingjærde
- Division of Biomedical Informatics, Department of Computer Science, University of Oslo, Norway
| | - S Lockmer
- Division of Hematology, Department of Medicine at Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - H Holte
- Department of Oncology, Oslo University Hospital, Oslo, Norway
| | - T Nedeva
- Institute of Pathology, University of Würzburg, Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | - T Grieb
- Institute of Pathology, University of Würzburg, Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | - B Sander
- Department of Laboratory Medicine, Division of Pathology, Karolinska Institutet, Stockholm, Sweden
| | - C Sundström
- Department of Pathology, Uppsala University Hospital, Uppsala University, Uppsala, Sweden
| | - R Spang
- Statistical Bioinformatics, Institute of Functional Genomics, University of Regensburg, Regensburg, Germany
| | - E Kimby
- Division of Hematology, Department of Medicine at Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - A Rosenwald
- Institute of Pathology, University of Würzburg, Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| |
Collapse
|
3
|
Ries M, Nippert F, März B, Alonso-Orts M, Grieb T, Hötzel R, Hille P, Emtenani P, Akinoglu EM, Speiser E, Plaickner J, Schörmann J, Auf der Maur M, Müller-Caspary K, Rosenauer A, Esser N, Eickhoff M, Wagner MR. Origin of the spectral red-shift and polarization patterns of self-assembled InGaN nanostructures on GaN nanowires. Nanoscale 2023; 15:7077-7085. [PMID: 36987591 DOI: 10.1039/d2nr05529e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The luminescence of InxGa1-xN nanowires (NWs) is frequently reported with large red-shifts as compared to the theoretical value expected from the average In content. Both compositional fluctuations and radial built-in fields were considered accountable for this effect, depending on the size, structure, composition, and surrounding medium of the NWs. In the present work, the emission properties of InGaN/GaN NWs grown by plasma-assisted molecular beam epitaxy are investigated in a comprehensive study combining ultraviolet-Raman and photoluminescence spectroscopy (PL) on vertical arrays, polarization-dependent PL on bundles of a few NWs, scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, and calculations of the band profiles. The roles of inhomogeneous In distribution and radial fields in the context of optical emission properties are addressed. The radial built-in fields are found to be modest, with a maximum surface band bending below 350 meV. On the other hand, variations in the local In content have been observed that give rise to potential fluctuations whose impact on the emission properties is shown to prevail over band-bending effects. Two luminescence bands with large positive and moderate negative polarization ratios of ≈+80% and ≤-60%, respectively, were observed. The red-shift in the luminescence is associated with In-rich inclusions in the NWs due to thermodynamic decomposition during growth. The negative polarization anisotropy is suggested to result from spontaneously formed superlattices in the In-rich regions of the NWs. The NWs show a preferred orthogonal absorption due to the dielectric boundary conditions and highlight the extreme sensitivity of these structures towards light polarization.
Collapse
Affiliation(s)
- Maximilian Ries
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstraße 36, 10623 Berlin, Germany.
- Leibniz-Institut für Analytische Wissenschaften - ISAS e.V., Department Interface Analytics, Schwarzschildstraße 8, 12489 Berlin, Germany
| | - Felix Nippert
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstraße 36, 10623 Berlin, Germany.
| | - Benjamin März
- Ernst-Ruska-Centre for Microscopy and Spectroscopy with Electrons at Forschungszentrum Jülich, Wilhelm-Johnen-Str., 52425 Jülich, Germany
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 11, 81377 Munich, Germany
| | - Manuel Alonso-Orts
- Universität Bremen, Institut für Festkörperphysik, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Tim Grieb
- Universität Bremen, Institut für Festkörperphysik, Otto-Hahn-Allee 1, 28359 Bremen, Germany
- Universität Bremen, MAPEX Center for Materials and Processes, Bibliothekstr. 1, 28359 Bremen, Germany
| | - Rudolfo Hötzel
- Universität Bremen, Institut für Festkörperphysik, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Pascal Hille
- Universität Bremen, Institut für Festkörperphysik, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Pouria Emtenani
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstraße 36, 10623 Berlin, Germany.
| | - Eser Metin Akinoglu
- Leibniz-Institut für Analytische Wissenschaften - ISAS e.V., Department Interface Analytics, Schwarzschildstraße 8, 12489 Berlin, Germany
| | - Eugen Speiser
- Leibniz-Institut für Analytische Wissenschaften - ISAS e.V., Department Interface Analytics, Schwarzschildstraße 8, 12489 Berlin, Germany
| | - Julian Plaickner
- Leibniz-Institut für Analytische Wissenschaften - ISAS e.V., Department Interface Analytics, Schwarzschildstraße 8, 12489 Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Jörg Schörmann
- Justus-Liebig-Universität Gießen, I. Physikalisches Institut und Zentrum für Materialforschung (LaMa), Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Matthias Auf der Maur
- University of Rome Tor Vergata, Department of Electronic Engineering, Via del Politecnico 1, 00133 Rome, Italy
| | - Knut Müller-Caspary
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 11, 81377 Munich, Germany
| | - Andreas Rosenauer
- Universität Bremen, Institut für Festkörperphysik, Otto-Hahn-Allee 1, 28359 Bremen, Germany
- Universität Bremen, MAPEX Center for Materials and Processes, Bibliothekstr. 1, 28359 Bremen, Germany
| | - Norbert Esser
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstraße 36, 10623 Berlin, Germany.
- Leibniz-Institut für Analytische Wissenschaften - ISAS e.V., Department Interface Analytics, Schwarzschildstraße 8, 12489 Berlin, Germany
| | - Martin Eickhoff
- Universität Bremen, Institut für Festkörperphysik, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Markus R Wagner
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstraße 36, 10623 Berlin, Germany.
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
| |
Collapse
|
4
|
Alonso-Orts M, Hötzel R, Grieb T, Auf der Maur M, Ries M, Nippert F, März B, Müller-Caspary K, Wagner MR, Rosenauer A, Eickhoff M. Correlative analysis on InGaN/GaN nanowires: structural and optical properties of self-assembled short-period superlattices. Nanoscale Res Lett 2023; 18:27. [PMID: 36856901 DOI: 10.1186/s11671-023-03808-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 02/20/2023] [Indexed: 05/24/2023]
Abstract
The influence of self-assembled short-period superlattices (SPSLs) on the structural and optical properties of InGaN/GaN nanowires (NWs) grown by PAMBE on Si (111) was investigated by STEM, EDXS, µ-PL analysis and k·p simulations. STEM analysis on single NWs indicates that in most of the studied nanostructures, SPSLs self-assemble during growth. The SPSLs display short-range ordering of In-rich and In-poor InxGa1-xN regions with a period of 2-3 nm that are covered by a GaN shell and that transition to a more homogenous InxGa1-xN core. Polarization- and temperature-resolved PL analysis performed on the same NWs shows that they exhibit a strong parallel polarized red-yellow emission and a predominantly perpendicular polarized blue emission, which are ascribed to different In-rich regions in the nanostructures. The correlation between STEM, µ-PL and k·p simulations provides better understanding of the rich optical emission of complex III-N nanostructures and how they are impacted by structural properties, yielding the significant impact of strain on self-assembly and spectral emission.
Collapse
Affiliation(s)
- Manuel Alonso-Orts
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee, 28359, Bremen, Germany.
| | - Rudolfo Hötzel
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee, 28359, Bremen, Germany
| | - Tim Grieb
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee, 28359, Bremen, Germany
| | - Matthias Auf der Maur
- Department of Electronic Engineering, University of Rome Tor Vergata, Via del Politecnico 1, 00133, Rome, Italy
| | - Maximilian Ries
- Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany
| | - Felix Nippert
- Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany
| | - Benjamin März
- Department of Chemistry and Centre for NanoScience, Ludwig-Maximilians-Universität Munich, Butenandtstr. 11, 81377, Munich, Germany
| | - Knut Müller-Caspary
- Department of Chemistry and Centre for NanoScience, Ludwig-Maximilians-Universität Munich, Butenandtstr. 11, 81377, Munich, Germany
| | - Markus R Wagner
- Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, 10623, Berlin, Germany
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., 10117, Berlin, Germany
| | - Andreas Rosenauer
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee, 28359, Bremen, Germany
| | - Martin Eickhoff
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee, 28359, Bremen, Germany
| |
Collapse
|
5
|
Krause FF, Schowalter M, Gerken B, Marquardt D, Grieb T, Mehrtens T, Mahr C, Rosenauer A. Dose efficient annular bright field contrast with the ISTEM method: A proof of principle demonstration. Ultramicroscopy 2023; 245:113661. [PMID: 36529039 DOI: 10.1016/j.ultramic.2022.113661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/21/2022] [Accepted: 12/03/2022] [Indexed: 12/13/2022]
Abstract
The ISTEM mode for TEM has been demonstrated to have several advantages in regard to resolution and precision. While previous works primarily focussed on the advantages due to the reduced spatial coherence, the actual image contrast, i.e. how bright or dark certain atom columns are imaged, has mostly been of secondary concern. The present work sets out to achieve the contrast of annular bright field STEM in ISTEM, producing the high contrast of light elements, for which this method is popular. It is shown from theoretical considerations that using an annular condenser aperture this aim can be realised. The optimal size of this aperture is found by simulative studies. It is then manufactured from platinum foil and installed in an image-aberration corrected microscope. ABF-like ISTEM images of strontium titanate in [100] projection are acquired. The pure oxygen columns are clearly resolved with significant contrast. The image pattern is indeed identical to what is achieved by ABF STEM. A close look at the image formation also shows that the dose needed for a given signal-to-noise ratio is at least a quarter smaller for ABF-like ISTEM compared to ABF STEM, assuming detectors of similar detective quantum efficiency.
Collapse
Affiliation(s)
- Florian F Krause
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany.
| | - Marco Schowalter
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Beeke Gerken
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Dennis Marquardt
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Tim Grieb
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Thorsten Mehrtens
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Christoph Mahr
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Andreas Rosenauer
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| |
Collapse
|
6
|
Grieb T, Krause FF, Müller-Caspary K, Ahl JP, Schowalter M, Oppermann O, Hertkorn J, Engl K, Rosenauer A. Angle-dependence of ADF-STEM intensities for chemical analysis of InGaN/GaN. Ultramicroscopy 2022; 238:113535. [DOI: 10.1016/j.ultramic.2022.113535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/08/2022] [Accepted: 04/17/2022] [Indexed: 11/30/2022]
|
7
|
Beyer A, Munde MS, Firoozabadi S, Heimes D, Grieb T, Rosenauer A, Müller-Caspary K, Volz K. Quantitative Characterization of Nanometer-Scale Electric Fields via Momentum-Resolved STEM. Nano Lett 2021; 21:2018-2025. [PMID: 33621104 DOI: 10.1021/acs.nanolett.0c04544] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Most of today's electronic devices, like solar cells and batteries, are based on nanometer-scale built-in electric fields. Accordingly, characterization of fields at such small scales has become an important task in the optimization of these devices. In this study, with GaAs-based p-n junctions as the example, key characteristics such as doping concentrations, polarity, and the depletion width are derived quantitatively using four-dimensional scanning transmission electron microscopy (4DSTEM). The built-in electric fields are determined by the shift they introduce to the center-of-mass of electron diffraction patterns at subnanometer spatial resolution. The method is applied successfully to characterize two p-n junctions with different doping concentrations. This highlights the potential of this method to directly visualize intentional or unintentional nanoscale electric fields in real-life devices, e.g., batteries, transistors, and solar cells.
Collapse
Affiliation(s)
- Andreas Beyer
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Manveer Singh Munde
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Saleh Firoozabadi
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Damien Heimes
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Tim Grieb
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Andreas Rosenauer
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Knut Müller-Caspary
- Ernst Ruska-Center for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, RWTH Aachen University, II. Institute of Physics, Otto-Blumenthal-Straße, Aachen 52074, Germany
| | - Kerstin Volz
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| |
Collapse
|
8
|
Grieb T, Krause FF, Müller-Caspary K, Firoozabadi S, Mahr C, Schowalter M, Beyer A, Oppermann O, Volz K, Rosenauer A. Angle-resolved STEM using an iris aperture: Scattering contributions and sources of error for the quantitative analysis in Si. Ultramicroscopy 2021; 221:113175. [PMID: 33383361 DOI: 10.1016/j.ultramic.2020.113175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 11/11/2020] [Accepted: 11/14/2020] [Indexed: 10/23/2022]
Abstract
The angle-resolved electron scattering is investigated in scanning-transmission electron microscopy (STEM) using a motorised iris aperture placed above a conventional annular detector. The electron intensity scattered into various angle ranges is compared with simulations that were carried out in the frozen-lattice approximation. As figure of merit for the agreement of experiment and simulation we evaluate the specimen thickness which is compared with the thickness obtained from position-averaged convergent beam electron diffraction (PACBED). We find deviations whose strengths depend on the angular range of the detected electrons. As possible sources of error we investigate, for example, the influences of amorphous surface layers, inelastic scattering (plasmon excitation), phonon-correlation within the frozen-lattice approach, and distortions in the diffraction plane of the microscope. The evaluation is performed for four experimental thicknesses and two angle-resolved STEM series under different camera lengths. The results clearly show that especially for scattering angles below 50 mrad, it is mandatory that the simulations take scattering effects into account which are usually neglected for simulating high-angle scattering. Most influences predominantly affect the low-angle range, but also high scattering angles can be affected (e.g. by amorphous surface covering).
Collapse
Affiliation(s)
- Tim Grieb
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany.
| | - Florian F Krause
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Knut Müller-Caspary
- Ernst Ruska-Center for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich 52425, Germany; RWTH Aachen University, II. Institute of Physics, Otto-Blumenthal-Straße, Aachen 52074, Germany
| | - Saleh Firoozabadi
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Christoph Mahr
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Marco Schowalter
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Andreas Beyer
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Oliver Oppermann
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Kerstin Volz
- Materials Science Centre and Department of Physics, Philipps University Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Andreas Rosenauer
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| |
Collapse
|
9
|
Müller-Caspary K, Grieb T, Müßener J, Gauquelin N, Hille P, Schörmann J, Verbeeck J, Van Aert S, Eickhoff M, Rosenauer A. Electrical Polarization in AlN/GaN Nanodisks Measured by Momentum-Resolved 4D Scanning Transmission Electron Microscopy. Phys Rev Lett 2019; 122:106102. [PMID: 30932647 DOI: 10.1103/physrevlett.122.106102] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Indexed: 05/27/2023]
Abstract
We report the mapping of polarization-induced internal electric fields in AlN/GaN nanowire heterostructures at unit cell resolution as a key for the correlation of optical and structural phenomena in semiconductor optoelectronics. Momentum-resolved aberration-corrected scanning transmission electron microscopy is employed as a new imaging mode that simultaneously provides four-dimensional data in real and reciprocal space. We demonstrate how internal mesoscale and atomic electric fields can be separated in an experiment, which is verified by comprehensive dynamical simulations of multiple electron scattering. A mean difference of 5.3±1.5 MV/cm is found for the polarization-induced electric fields in AlN and GaN, being in accordance with dedicated simulations and photoluminescence measurements in previous publications.
Collapse
Affiliation(s)
- Knut Müller-Caspary
- Ernst-Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52425 Jülich, Germany
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Tim Grieb
- IFP, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
- MAPEX Center for Materials and Processes, University of Bremen, Bibliothekstraße 1, 28359 Bremen, Germany
| | - Jan Müßener
- IFP, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Nicolas Gauquelin
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Pascal Hille
- IFP, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Jörg Schörmann
- I. Physikalisches Institut, Justus-Liebig University Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Johan Verbeeck
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Sandra Van Aert
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Martin Eickhoff
- IFP, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Andreas Rosenauer
- IFP, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
- MAPEX Center for Materials and Processes, University of Bremen, Bibliothekstraße 1, 28359 Bremen, Germany
| |
Collapse
|
10
|
Mahr C, Müller-Caspary K, Ritz R, Simson M, Grieb T, Schowalter M, Krause FF, Lackmann A, Soltau H, Wittstock A, Rosenauer A. Influence of distortions of recorded diffraction patterns on strain analysis by nano-beam electron diffraction. Ultramicroscopy 2019; 196:74-82. [DOI: 10.1016/j.ultramic.2018.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 09/19/2018] [Accepted: 09/20/2018] [Indexed: 10/28/2022]
|
11
|
Chatterjee D, Shetty S, Müller-Caspary K, Grieb T, Krause FF, Schowalter M, Rosenauer A, Ravishankar N. Correction to Ultrathin Au-Alloy Nanowires at the Liquid-Liquid Interface. Nano Lett 2018; 18:4059. [PMID: 29767531 DOI: 10.1021/acs.nanolett.8b01943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
|
12
|
Krause FF, Bredemeier D, Schowalter M, Mehrtens T, Grieb T, Rosenauer A. Using molecular dynamics for multislice TEM simulation of thermal diffuse scattering in AlGaN. Ultramicroscopy 2018; 189:124-135. [PMID: 29660631 DOI: 10.1016/j.ultramic.2018.03.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/22/2018] [Accepted: 03/28/2018] [Indexed: 10/17/2022]
Abstract
For simulation of transmission electron microscopic images and diffraction patterns, the accurate inclusion of thermal diffuse scattering by phonons is important. In the frozen phonon multislice algorithm, this is possible, if thermal displacements according to the realistic, quantum mechanical distribution can be generated. For pure crystals, quantum mechanical calculations based on DFT yield those displacements. But for alloys one is usually restricted to the Einstein approximation, where correlations between atoms are neglected. In this article, molecular dynamics simulations are discussed and used as an alternative method for displacement calculation. Employing an empirical Stillinger-Weber type potential, classical motion is used as an approximation for the quantum mechanical dynamics. Thereby, correlations and possible static atomic displacements are inherently included. An appropriate potential is devised for AlGaN by fitting to force constant matrices determined from DFT and elastic constants of AlN and GaN. A comparison shows that the empiric potential reproduces phonon dispersions and displacement expectations from DFT references. The validity for alloys is successfully demonstrated by comparison to DFT calculations in special quasirandom structures. Subsequently, molecular dynamics were used in multislice simulations of both conventional and scanning TEM images. The resulting images are in very good agreement with DFT based calculations, while a slight yet significant deviation from Einstein approximation results can be seen, which can be attributed to the neglect of correlations in the latter. The presented potential hence proves to be a useful tool for accurate TEM simulations of AlGaN alloys.
Collapse
Affiliation(s)
- Florian F Krause
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany.
| | - Dennis Bredemeier
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany; Institute for Solar Energy Research Hamelin, Am Ohrberg 1, Emmerthal 31860, Germany
| | - Marco Schowalter
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Thorsten Mehrtens
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Tim Grieb
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| | - Andreas Rosenauer
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen 28359, Germany
| |
Collapse
|
13
|
Chatterjee D, Shetty S, Müller-Caspary K, Grieb T, Krause FF, Schowalter M, Rosenauer A, Ravishankar N. Ultrathin Au-Alloy Nanowires at the Liquid-Liquid Interface. Nano Lett 2018; 18:1903-1907. [PMID: 29397751 DOI: 10.1021/acs.nanolett.7b05217] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ultrathin bimetallic nanowires are of importance and interest for applications in electronic devices such as sensors and heterogeneous catalysts. In this work, we have designed a new, highly reproducible and generalized wet chemical method to synthesize uniform and monodispersed Au-based alloy (AuCu, AuPd, and AuPt) nanowires with tunable composition using microwave-assisted reduction at the liquid-liquid interface. These ultrathin alloy nanowires are below 4 nm in diameter and about 2 μm long. Detailed microstructural characterization shows that the wires have an face centred cubic (FCC) crystal structure, and they have low-energy twin-boundary and stacking-fault defects along the growth direction. The wires exhibit remarkable thermal and mechanical stability that is critical for important applications. The alloy wires exhibit excellent electrocatalytic activity for methanol oxidation in an alkaline medium.
Collapse
Affiliation(s)
- Dipanwita Chatterjee
- Materials Research Centre , Indian Institute of Science , Bangalore 560012 , India
| | - Shwetha Shetty
- Materials Research Centre , Indian Institute of Science , Bangalore 560012 , India
| | | | - Tim Grieb
- University of Bremen , Otto-Hahn-Allee 1 , D-28359 Bremen , Germany
| | - Florian F Krause
- University of Bremen , Otto-Hahn-Allee 1 , D-28359 Bremen , Germany
| | - Marco Schowalter
- University of Bremen , Otto-Hahn-Allee 1 , D-28359 Bremen , Germany
| | | | | |
Collapse
|
14
|
Grieb T, Tewes M, Schowalter M, Müller-Caspary K, Krause FF, Mehrtens T, Hartmann JM, Rosenauer A. Quantitative HAADF STEM of SiGe in presence of amorphous surface layers from FIB preparation. Ultramicroscopy 2018; 184:29-36. [DOI: 10.1016/j.ultramic.2017.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 09/08/2017] [Accepted: 09/26/2017] [Indexed: 11/27/2022]
|
15
|
Meierhofer F, Li H, Gockeln M, Kun R, Grieb T, Rosenauer A, Fritsching U, Kiefer J, Birkenstock J, Mädler L, Pokhrel S. Screening Precursor-Solvent Combinations for Li 4Ti 5O 12 Energy Storage Material Using Flame Spray Pyrolysis. ACS Appl Mater Interfaces 2017; 9:37760-37777. [PMID: 28960057 DOI: 10.1021/acsami.7b11435] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The development and industrial application of advanced lithium based energy-storage materials are directly related to the innovative production techniques and the usage of inexpensive precursor materials. Flame spray pyrolysis (FSP) is a promising technique that overcomes the challenges in the production processes such as scalability, process control, material versatility, and cost. In the present study, phase pure anode material Li4Ti5O12 (LTO) was designed using FSP via extensive systematic screening of lithium and titanium precursors dissolved in five different organic solvents. The effect of precursor and solvent parameters such as chemical reactivity, boiling point, and combustion enthalpy on the particle formation either via gas-to-particle (evaporation/nucleation/growth) or via droplet-to-particle (precipitation/incomplete evaporation) is discussed. The presence of carboxylic acid in the precursor solution resulted in pure (>95 mass %) and homogeneous LTO nanoparticles of size 4-9 nm, attributed to two reasons: (1) stabilization of water sensitive metal alkoxides precursor and (2) formation of volatile carboxylates from lithium nitrate evidenced by attenuated total reflection Fourier transform infrared spectroscopy and single droplet combustion experiments. In contrast, the absence of carboxylic acids resulted in larger inhomogeneous crystalline titanium dioxide (TiO2) particles with significant reduction of LTO content as low as ∼34 mass %. In-depth particle characterization was performed using X-ray diffraction with Rietveld refinement, thermogravimetric analysis coupled with differential scanning calorimetry and mass spectrometry, gas adsorption, and vibrational spectroscopy. High-resolution transmission electron microscopy of the LTO product revealed excellent quality of the particles obtained at high temperature. In addition, high rate capability and efficient charge reversibility of LTO nanoparticles demonstrate the vast potential of inexpensive gas-phase synthesis for energy-storage materials.
Collapse
Affiliation(s)
- Florian Meierhofer
- Foundation Institute of Materials Science, Department of Production Engineering, University of Bremen , 28359 Bremen, Germany
| | - Haipeng Li
- Foundation Institute of Materials Science, Department of Production Engineering, University of Bremen , 28359 Bremen, Germany
| | - Michael Gockeln
- Innovative Sensor and Functional Materials Research Group, Department of Production Engineering, University of Bremen , 28359 Bremen, Germany
| | - Robert Kun
- Innovative Sensor and Functional Materials Research Group, Department of Production Engineering, University of Bremen , 28359 Bremen, Germany
- Fraunhofer Institute for Manufacturing Technology and Advanced Materials, IFAM , 28359 Bremen, Germany
| | - Tim Grieb
- Institute of Solid State Physics, Electron Microscopy, University of Bremen , 28359 Bremen, Germany
| | - Andreas Rosenauer
- Institute of Solid State Physics, Electron Microscopy, University of Bremen , 28359 Bremen, Germany
- MAPEX Center for Materials and Processes, University of Bremen , 28359 Bremen, Germany
| | - Udo Fritsching
- Foundation Institute of Materials Science, Department of Production Engineering, University of Bremen , 28359 Bremen, Germany
- MAPEX Center for Materials and Processes, University of Bremen , 28359 Bremen, Germany
| | - Johannes Kiefer
- Technische Thermodynamik, University of Bremen , 28359 Bremen, Germany
- MAPEX Center for Materials and Processes, University of Bremen , 28359 Bremen, Germany
| | - Johannes Birkenstock
- Central Laboratory for Crystallography and Applied Materials, University of Bremen , 28359 Bremen, Germany
| | - Lutz Mädler
- Foundation Institute of Materials Science, Department of Production Engineering, University of Bremen , 28359 Bremen, Germany
- MAPEX Center for Materials and Processes, University of Bremen , 28359 Bremen, Germany
| | - Suman Pokhrel
- Foundation Institute of Materials Science, Department of Production Engineering, University of Bremen , 28359 Bremen, Germany
| |
Collapse
|
16
|
Chery N, Ngo TH, Chauvat MP, Damilano B, Courville A, DE Mierry P, Grieb T, Mehrtens T, Krause FF, Müller-Caspary K, Schowalter M, Gil B, Rosenauer A, Ruterana P. The microstructure, local indium composition and photoluminescence in green-emitting InGaN/GaN quantum wells. J Microsc 2017; 268:305-312. [PMID: 29023712 DOI: 10.1111/jmi.12657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 09/19/2017] [Accepted: 09/19/2017] [Indexed: 11/26/2022]
Abstract
In this work, we analyse the microstructure and local chemical composition of green-emitting Inx Ga1-x N/GaN quantum well (QW) heterostructures in correlation with their emission properties. Two samples of high structural quality grown by metalorganic vapour phase epitaxy (MOVPE) with a nominal composition of x = 0.15 and 0.18 indium are discussed. The local indium composition is quantitatively evaluated by comparing scanning transmission electron microscopy (STEM) images to simulations and the local indium concentration is extracted from intensity measurements. The calculations point out that the measured indium fluctuations may be correlated to the large width and intensity decrease of the PL emission peak.
Collapse
Affiliation(s)
- N Chery
- CIMAP, 6 Boulevard du Maréchal Juin, Caen, France
| | - T H Ngo
- Laboratoire Charles Coulomb, Batiment 21, Campus Triolet, Université de Montpellier, Montpellier, France
| | - M P Chauvat
- CIMAP, 6 Boulevard du Maréchal Juin, Caen, France
| | - B Damilano
- Université Côte d'Azur, CRHEA, CNRS, France
| | | | | | - T Grieb
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - T Mehrtens
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - F F Krause
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - K Müller-Caspary
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - M Schowalter
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - B Gil
- Laboratoire Charles Coulomb, Batiment 21, Campus Triolet, Université de Montpellier, Montpellier, France
| | - A Rosenauer
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, Bremen, Germany
| | - P Ruterana
- CIMAP, 6 Boulevard du Maréchal Juin, Caen, France
| |
Collapse
|
17
|
Grieb T, Krause FF, Mahr C, Zillmann D, Müller-Caspary K, Schowalter M, Rosenauer A. Optimization of NBED simulations for disc-detection measurements. Ultramicroscopy 2017; 181:50-60. [DOI: 10.1016/j.ultramic.2017.04.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 03/28/2017] [Accepted: 04/28/2017] [Indexed: 10/19/2022]
|
18
|
Teck M, Murshed MM, Schowalter M, Lefeld N, Grossmann HK, Grieb T, Hartmann T, Robben L, Rosenauer A, Mädler L, Gesing TM. Structural and spectroscopic comparison between polycrystalline, nanocrystalline and quantum dot visible light photo-catalyst Bi 2 WO 6. J SOLID STATE CHEM 2017. [DOI: 10.1016/j.jssc.2017.07.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
19
|
Müßener J, Hille P, Grieb T, Schörmann J, Teubert J, Monroy E, Rosenauer A, Eickhoff M. Bias-Controlled Optical Transitions in GaN/AlN Nanowire Heterostructures. ACS Nano 2017; 11:8758-8767. [PMID: 28771318 DOI: 10.1021/acsnano.7b02419] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report on the control and modification of optical transitions in 40× GaN/AlN heterostructure superlattices embedded in GaN nanowires by an externally applied bias. The complex band profile of these multi-nanodisc heterostructures gives rise to a manifold of optical transitions, whose emission characteristic is strongly influenced by polarization-induced internal electric fields. We demonstrate that the superposition of an external axial electric field along a single contacted nanowire leads to specific modifications of each photoluminescence emission, which allows to investigate and identify their origin and to control their characteristic properties in terms of transition energy, intensity and decay time. Using this approach, direct transitions within one nanodisc, indirect transitions between adjacent nanodiscs, transitions at the top/bottom edge of the heterostructure, and the GaN near-band-edge emission can be distinguished. While the transition energy of the direct transition can be shifted by external bias over a range of 450 meV and changed in intensity by a factor of 15, the indirect transition exhibits an inverse bias dependence and is only observable and spectrally separated when external bias is applied. In addition, by tuning the band profile close to flat band conditions, the direction and magnitude of the internal electric field can be estimated, which is of high interest for the polar group III-nitrides. The direct control of emission properties over a wide range bears possible application in tunable optoelectronic devices. For more fundamental studies, single-nanowire heterostructures provide a well-defined and isolated system to investigate and control interaction processes in coupled quantum structures.
Collapse
Affiliation(s)
- Jan Müßener
- Institut für Festkörperphysik, Universität Bremen , Otto-Hahn-Allee 1, 28359 Bremen, Germany
- I. Physikalisches Institut, Justus-Liebig-Universität Gießen , Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Pascal Hille
- Institut für Festkörperphysik, Universität Bremen , Otto-Hahn-Allee 1, 28359 Bremen, Germany
- I. Physikalisches Institut, Justus-Liebig-Universität Gießen , Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Tim Grieb
- Institut für Festkörperphysik, Universität Bremen , Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Jörg Schörmann
- I. Physikalisches Institut, Justus-Liebig-Universität Gießen , Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Jörg Teubert
- I. Physikalisches Institut, Justus-Liebig-Universität Gießen , Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Eva Monroy
- Université Grenoble-Alpes , 38000 Grenoble, France
- CEA-Grenoble, INAC-PHELIQS , 17 Avenue des Martyrs, 38054 Grenoble, France
| | - Andreas Rosenauer
- Institut für Festkörperphysik, Universität Bremen , Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Martin Eickhoff
- Institut für Festkörperphysik, Universität Bremen , Otto-Hahn-Allee 1, 28359 Bremen, Germany
- I. Physikalisches Institut, Justus-Liebig-Universität Gießen , Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| |
Collapse
|
20
|
Zamò A, Pischimarov J, Schlesner M, Rosenstiel P, Bomben R, Horn H, Grieb T, Nedeva T, López C, Haake A, Richter J, Trümper L, Lawerenz C, Klapper W, Möller P, Hummel M, Lenze D, Szczepanowski M, Flossbach L, Schreder M, Gattei V, Ott G, Siebert R, Rosenwald A, Leich E. Differences between BCL2-break positive and negative follicular lymphoma unraveled by whole-exome sequencing. Leukemia 2017; 32:685-693. [PMID: 28824170 DOI: 10.1038/leu.2017.270] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 08/08/2017] [Indexed: 12/25/2022]
Abstract
Depending on disease stage follicular lymphoma (FL) lack the t(14;18) in ~15-~50% of cases. Nevertheless, most of these cases express BCL2. To elucidate mechanisms triggering BCL2 expression and promoting pathogenesis in t(14;18)-negative FL, exonic single-nucleotide variant (SNV) profiles of 28 t(14;18)-positive and 13 t(14;18)-negative FL were analyzed, followed by the integration of copy-number changes, copy-neutral LOH and published gene-expression data as well as the assessment of immunoglobulin N-glycosylation sites. Typical FL mutations also affected t(14;18)-negative FL. Curated gene set/pathway annotation of genes mutated in either t(14;18)-positive or t(14;18)-negative FL revealed a strong enrichment of same or similar gene sets but also a more prominent or exclusive enrichment of immune response and N-glycosylation signatures in t(14;18)-negative FL. Mutated genes showed high BCL2 association in both subgroups. Among the genes mutated in t(14;18)-negative FL 555 were affected by copy-number alterations and/or copy-neutral LOH and 96 were differently expressed between t(14;18)-positive and t(14;18)-negative FL (P<0.01). N-glycosylation sites were detected considerably less frequently in t(14;18)-negative FL. These results suggest a diverse portfolio of genetic alterations that may induce or regulate BCL2 expression or promote pathogenesis of t(14;18)-negative FL as well as a less specific but increased crosstalk with the microenvironment that may compensate for the lack of N-glycosylation.
Collapse
Affiliation(s)
- A Zamò
- Institute of Pathology, University of Würzburg, Würzburg, Würzburg, Germany.,Department of Diagnostic and Public Health, University of Verona, Verona, Italy.,Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | - J Pischimarov
- Institute of Pathology, University of Würzburg, Würzburg, Würzburg, Germany.,Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | - M Schlesner
- Theoretical Bioinformatics (B080), Computational Oncology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - P Rosenstiel
- Institute for Clinical Molecular Biology, Christian-Albrechts-University, Kiel, Germany
| | - R Bomben
- Department of Translational Research, CRO, Aviano, Italy
| | - H Horn
- Dr Margarete Fischer-Bosch-Institute for Clinical Pharmacology, Stuttgart, Germany
| | - T Grieb
- Institute of Pathology, University of Würzburg, Würzburg, Würzburg, Germany.,Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | - T Nedeva
- Institute of Pathology, University of Würzburg, Würzburg, Würzburg, Germany.,Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | - C López
- Institute for Human Genetics, University Hospital Ulm, Ulm, Germany.,Institute for Human Genetics, University Hospital Schleswig-Holstein, Kiel, Germany
| | - A Haake
- Institute for Human Genetics, University Hospital Schleswig-Holstein, Kiel, Germany
| | - J Richter
- Institute for Human Genetics, University Hospital Schleswig-Holstein, Kiel, Germany.,Institute of Pathology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - L Trümper
- Department of Hematology and Medical Oncology, University Hospital, Göttingen, Germany
| | - C Lawerenz
- Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - W Klapper
- Institute of Pathology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - P Möller
- Institute of Pathology, University Hospital Ulm, Ulm, Germany
| | - M Hummel
- Institute of Pathology, Charité-University Hospital Berlin, Germany
| | - D Lenze
- Institute of Pathology, Charité-University Hospital Berlin, Germany
| | - M Szczepanowski
- Institute of Pathology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - L Flossbach
- Institute of Pathology, University of Würzburg, Würzburg, Würzburg, Germany.,Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | - M Schreder
- Medizinische Klinik und Poliklinik II, University Hospital Würzburg, Würzburg, Germany
| | - V Gattei
- Department of Translational Research, CRO, Aviano, Italy
| | - G Ott
- Department of Clinical Pathology, Robert-Bosch-Krankenhaus, Stuttgart, Germany
| | - R Siebert
- Institute for Human Genetics, University Hospital Ulm, Ulm, Germany.,Institute for Human Genetics, University Hospital Schleswig-Holstein, Kiel, Germany
| | - A Rosenwald
- Institute of Pathology, University of Würzburg, Würzburg, Würzburg, Germany.,Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | - E Leich
- Institute of Pathology, University of Würzburg, Würzburg, Würzburg, Germany.,Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| |
Collapse
|
21
|
Müller-Caspary K, Krause FF, Grieb T, Löffler S, Schowalter M, Béché A, Galioit V, Marquardt D, Zweck J, Schattschneider P, Verbeeck J, Rosenauer A. Measurement of atomic electric fields and charge densities from average momentum transfers using scanning transmission electron microscopy. Ultramicroscopy 2017; 178:62-80. [PMID: 27217350 DOI: 10.1016/j.ultramic.2016.05.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/04/2016] [Accepted: 05/07/2016] [Indexed: 10/21/2022]
Abstract
This study sheds light on the prerequisites, possibilities, limitations and interpretation of high-resolution differential phase contrast (DPC) imaging in scanning transmission electron microscopy (STEM). We draw particular attention to the well-established DPC technique based on segmented annular detectors and its relation to recent developments based on pixelated detectors. These employ the expectation value of the momentum transfer as a reliable measure of the angular deflection of the STEM beam induced by an electric field in the specimen. The influence of scattering and propagation of electrons within the specimen is initially discussed separately and then treated in terms of a two-state channeling theory. A detailed simulation study of GaN is presented as a function of specimen thickness and bonding. It is found that bonding effects are rather detectable implicitly, e.g., by characteristics of the momentum flux in areas between the atoms than by directly mapping electric fields and charge densities. For strontium titanate, experimental charge densities are compared with simulations and discussed with respect to experimental artifacts such as scan noise. Finally, we consider practical issues such as figures of merit for spatial and momentum resolution, minimum electron dose, and the mapping of larger-scale, built-in electric fields by virtue of data averaged over a crystal unit cell. We find that the latter is possible for crystals with an inversion center. Concerning the optimal detector design, this study indicates that a sampling of 5mrad per pixel is sufficient in typical applications, corresponding to approximately 10×10 available pixels.
Collapse
Affiliation(s)
- Knut Müller-Caspary
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany.
| | - Florian F Krause
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany.
| | - Tim Grieb
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Stefan Löffler
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10/E138, A-1040 Vienna, Austria; University Service Centre for Transmission Electron Microscopy, Wiedner Hauptstraße 8-10/E052, A-1040 Vienna, Austria
| | - Marco Schowalter
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Armand Béché
- EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Vincent Galioit
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93040 Regensburg, Germany
| | - Dennis Marquardt
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Josef Zweck
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93040 Regensburg, Germany
| | - Peter Schattschneider
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10/E138, A-1040 Vienna, Austria; University Service Centre for Transmission Electron Microscopy, Wiedner Hauptstraße 8-10/E052, A-1040 Vienna, Austria
| | - Johan Verbeeck
- EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Andreas Rosenauer
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| |
Collapse
|
22
|
Carvalho D, Müller-Caspary K, Schowalter M, Grieb T, Mehrtens T, Rosenauer A, Ben T, García R, Redondo-Cubero A, Lorenz K, Daudin B, Morales FM. Direct Measurement of Polarization-Induced Fields in GaN/AlN by Nano-Beam Electron Diffraction. Sci Rep 2016; 6:28459. [PMID: 27350322 PMCID: PMC4923855 DOI: 10.1038/srep28459] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 06/06/2016] [Indexed: 11/30/2022] Open
Abstract
The built-in piezoelectric fields in group III-nitrides can act as road blocks on the way to maximizing the efficiency of opto-electronic devices. In order to overcome this limitation, a proper characterization of these fields is necessary. In this work nano-beam electron diffraction in scanning transmission electron microscopy mode has been used to simultaneously measure the strain state and the induced piezoelectric fields in a GaN/AlN multiple quantum well system.
Collapse
Affiliation(s)
- Daniel Carvalho
- Department of Materials Science and Metallurgic Engineering, and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Spain.,IMEYMAT: Institute of Research on Electron Microscopy and Materials of the University of Cádiz, Spain
| | - Knut Müller-Caspary
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Marco Schowalter
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Tim Grieb
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Thorsten Mehrtens
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Andreas Rosenauer
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Teresa Ben
- Department of Materials Science and Metallurgic Engineering, and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Spain.,IMEYMAT: Institute of Research on Electron Microscopy and Materials of the University of Cádiz, Spain
| | - Rafael García
- Department of Materials Science and Metallurgic Engineering, and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Spain.,IMEYMAT: Institute of Research on Electron Microscopy and Materials of the University of Cádiz, Spain
| | - Andrés Redondo-Cubero
- IPFN, Instituto Superior Técnico, Campus Tecnológico e Nuclear, Universidade de Lisboa, 2695-066 Bobadela LRS, Portugal.,Departamento de Física Aplicada y Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Katharina Lorenz
- IPFN, Instituto Superior Técnico, Campus Tecnológico e Nuclear, Universidade de Lisboa, 2695-066 Bobadela LRS, Portugal
| | - Bruno Daudin
- Univ. Grenoble Alpes, CEA/CNRS Group, "Nanophysique et Semiconducteurs", F-38000 Grenoble, France
| | - Francisco M Morales
- Department of Materials Science and Metallurgic Engineering, and Inorganic Chemistry, Faculty of Sciences, University of Cádiz, Spain.,IMEYMAT: Institute of Research on Electron Microscopy and Materials of the University of Cádiz, Spain
| |
Collapse
|
23
|
Richards MK, Yanez D, Goldin AB, Grieb T, Murphy WM, Drugas GT. Factors associated with 30-day unplanned pediatric surgical readmission. Am J Surg 2016; 212:426-32. [PMID: 26924805 DOI: 10.1016/j.amjsurg.2015.12.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 12/02/2015] [Accepted: 12/10/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND Unplanned readmissions are costly to family satisfaction and negatively associated with quality of care. We hypothesized that patient, operative, and hospital factors would be associated with pediatric readmission. METHODS All patients with an inpatient operation from 10/1/2008 to 7/28/2014 at a freestanding children's hospital were included. A retrospective cohort study using multivariable forward stepwise logistic regression determined factors associated with unplanned readmission within 30 days of discharge. RESULTS Among 20,785 patients with an operation there were 26,978 encounters and 3,092 readmissions (11.5%). Thirteen of 33 candidate variables considered in the stepwise regression were significantly associated with readmission. Patients with an emergency department visit within 365 days of operation, American Society of Anesthesiologists class 4 or greater, Hispanic ethnicity and late-day or holiday/weekend discharges were more likely to have an unplanned readmission (odds ratio [OR] = 1.96; 95% confidence interval [CI] = 1.76 to 2.19, OR = 2.00; 95% CI = 1.58 to 2.53, OR = 1.16; 95% CI = 1.04 to 1.29, OR = 2.27; 95% CI = 1.55 to 3.63. respectively). CONCLUSIONS Patient and hospital factors may be associated with readmission. Day and time of discharge represent variability of care and are important targets for hospital initiatives to decrease unplanned readmission.
Collapse
Affiliation(s)
- Morgan K Richards
- Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA 98105, USA; University of Washington Medical Center, 1949 NE Pacific Street, Seattle, WA 98195, USA.
| | - David Yanez
- University of Washington Medical Center, 1949 NE Pacific Street, Seattle, WA 98195, USA
| | - Adam B Goldin
- Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA 98105, USA
| | - Tim Grieb
- Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA 98105, USA
| | - Whitney M Murphy
- Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA 98105, USA
| | - George T Drugas
- Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA 98105, USA
| |
Collapse
|
24
|
Krause FF, Schowalter M, Grieb T, Müller-Caspary K, Mehrtens T, Rosenauer A. Effects of instrument imperfections on quantitative scanning transmission electron microscopy. Ultramicroscopy 2016; 161:146-160. [DOI: 10.1016/j.ultramic.2015.10.026] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/26/2015] [Accepted: 10/29/2015] [Indexed: 10/22/2022]
|
25
|
Mahr C, Müller-Caspary K, Grieb T, Schowalter M, Mehrtens T, Krause FF, Zillmann D, Rosenauer A. Theoretical study of precision and accuracy of strain analysis by nano-beam electron diffraction. Ultramicroscopy 2015; 158:38-48. [DOI: 10.1016/j.ultramic.2015.06.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/08/2015] [Accepted: 06/11/2015] [Indexed: 10/23/2022]
|
26
|
Dreyer JA, Grossmann HK, Chen J, Grieb T, Gong BB, Sit PHL, Mädler L, Teoh WY. Preferential oxidation of carbon monoxide over Pt–FeO /CeO2 synthesized by two-nozzle flame spray pyrolysis. J Catal 2015. [DOI: 10.1016/j.jcat.2015.05.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
27
|
Grieb T, Müller K, Cadel E, Beyer A, Schowalter M, Talbot E, Volz K, Rosenauer A. Simultaneous quantification of indium and nitrogen concentration in InGaNAs using HAADF-STEM. Microsc Microanal 2014; 20:1740-1752. [PMID: 25268110 DOI: 10.1017/s1431927614013051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
To unambiguously evaluate the indium and nitrogen concentrations in In(x)Ga(1-x)N(y)As(1-y), two independent sources of information must be obtained experimentally. Based on high-resolution scanning transmission electron microscopy (STEM) images taken with a high-angle annular dark-field (HAADF) detector the strain state of the InGaNAs quantum well is determined as well as its characteristic HAADF-scattering intensity. The strain state is evaluated by applying elasticity theory and the HAADF intensity is used for a comparison with multislice simulations. The combination of both allows for determination of the chemical composition where the results are in accordance with X-ray diffraction measurements, three-dimensional atom probe tomography, and further transmission electron microscopy analysis. The HAADF-STEM evaluation was used to investigate the influence of As-stabilized annealing on the InGaNAs/GaAs sample. Photoluminescence measurements show an annealing-induced blue shift of the emission wavelength. The chemical analysis precludes an elemental diffusion as origin of the energy shift--instead the results are in agreement with a model based on an annealing-induced redistribution of the atomic next-neighbor configuration.
Collapse
Affiliation(s)
- Tim Grieb
- 1Institute of Solid State Physics,University of Bremen,Otto-Hahn-Allee 1,28359 Bremen,Germany
| | - Knut Müller
- 1Institute of Solid State Physics,University of Bremen,Otto-Hahn-Allee 1,28359 Bremen,Germany
| | - Emmanuel Cadel
- 2Groupe de Physique des Matériaux (GPM) UMR 6634,Normandie Université,Université et INSA de RouenCNRS,Av. de l'Université,BP 12,76801 Saint Etienne du Rouvray,France
| | - Andreas Beyer
- 3Materials Science Center and Faculty of Physics,Philipps University Marburg,Hans Meerwein Straße,35032 Marburg,Germany
| | - Marco Schowalter
- 1Institute of Solid State Physics,University of Bremen,Otto-Hahn-Allee 1,28359 Bremen,Germany
| | - Etienne Talbot
- 2Groupe de Physique des Matériaux (GPM) UMR 6634,Normandie Université,Université et INSA de RouenCNRS,Av. de l'Université,BP 12,76801 Saint Etienne du Rouvray,France
| | - Kerstin Volz
- 3Materials Science Center and Faculty of Physics,Philipps University Marburg,Hans Meerwein Straße,35032 Marburg,Germany
| | - Andreas Rosenauer
- 1Institute of Solid State Physics,University of Bremen,Otto-Hahn-Allee 1,28359 Bremen,Germany
| |
Collapse
|
28
|
Mädler L, Gröhn A, Grieb T, Fritsching U, Wegner K, Grossmann H. Size- and Composite-Controlled Synthesis of Multi Oxide Nanoparticles Using Double-Flame Spray Pyrolysis. CHEM-ING-TECH 2014. [DOI: 10.1002/cite.201450166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
29
|
|
30
|
Juluri RR, Rath A, Ghosh A, Bhukta A, Sathyavathi R, Rao DN, Müller K, Schowalter M, Frank K, Grieb T, Krause F, Rosenauer A, Satyam PV. Coherently embedded Ag nanostructures in Si: 3D imaging and their application to SERS. Sci Rep 2014; 4:4633. [PMID: 24717601 PMCID: PMC3982172 DOI: 10.1038/srep04633] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 03/24/2014] [Indexed: 11/09/2022] Open
Abstract
Surface enhanced Raman spectroscopy (SERS) has been established as a powerful tool to detect very low-concentration bio-molecules. One of the challenging problems is to have reliable and robust SERS substrate. Here, we report on a simple method to grow coherently embedded (endotaxial) silver nanostructures in silicon substrates, analyze their three-dimensional shape by scanning transmission electron microscopy tomography and demonstrate their use as a highly reproducible and stable substrate for SERS measurements. Bi-layers consisting of Ag and GeOx thin films were grown on native oxide covered silicon substrate using a physical vapor deposition method. Followed by annealing at 800°C under ambient conditions, this resulted in the formation of endotaxial Ag nanostructures of specific shape depending upon the substrate orientation. These structures are utilized for detection of Crystal Violet molecules of 5 × 10−10 M concentrations. These are expected to be one of the highly robust, reusable and novel substrates for single molecule detection.
Collapse
Affiliation(s)
- R R Juluri
- Institute of Physics, Sachivalaya Marg, Bhubaneswar, Odisha-751005, India
| | - A Rath
- 1] Institute of Physics, Sachivalaya Marg, Bhubaneswar, Odisha-751005, India [2]
| | - A Ghosh
- Institute of Physics, Sachivalaya Marg, Bhubaneswar, Odisha-751005, India
| | - A Bhukta
- Institute of Physics, Sachivalaya Marg, Bhubaneswar, Odisha-751005, India
| | - R Sathyavathi
- School of Physics, University of Hyderabad, Hyderabad - 500 046, India
| | - D Narayana Rao
- School of Physics, University of Hyderabad, Hyderabad - 500 046, India
| | - Knut Müller
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Marco Schowalter
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Kristian Frank
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Tim Grieb
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - Florian Krause
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - A Rosenauer
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
| | - P V Satyam
- Institute of Physics, Sachivalaya Marg, Bhubaneswar, Odisha-751005, India
| |
Collapse
|
31
|
Rath A, Dash JK, Juluri RR, Ghosh A, Grieb T, Schowalter M, Krause FF, Müller K, Rosenauer A, Satyam PV. A study of the initial stages of the growth of Au-assisted epitaxial Ge nanowires on a clean Ge(100) surface. CrystEngComm 2014. [DOI: 10.1039/c3ce42254b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
32
|
Grieb T, Müller K, Fritz R, Grillo V, Schowalter M, Volz K, Rosenauer A. Quantitative chemical evaluation of dilute GaNAs using ADF STEM: Avoiding surface strain induced artifacts. Ultramicroscopy 2013; 129:1-9. [DOI: 10.1016/j.ultramic.2013.02.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 02/05/2013] [Accepted: 02/09/2013] [Indexed: 11/27/2022]
|
33
|
Wehling J, Volkmann E, Grieb T, Rosenauer A, Maas M, Treccani L, Rezwan K. A critical study: assessment of the effect of silica particles from 15 to 500 nm on bacterial viability. Environ Pollut 2013; 176:292-299. [PMID: 23455355 DOI: 10.1016/j.envpol.2013.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 01/29/2013] [Accepted: 02/01/2013] [Indexed: 06/01/2023]
Abstract
The current opinion on the toxicity of nanomaterials converges on a size-dependent phenomenon showing increasing toxicity with decreasing particle sizes. We demonstrate that SiO2 particles have no or only a mild effect on the viability of five bacterial strains, independently from the particle size. A two-hour exposure to 20 mg L(-1) of 15, 50 and 500 nm sized SiO2 particles neither alters bacterial adenosine triphosphate (ATP) levels nor reduces the number of colony forming units (CFU). Additionally, we tested the effect of Al2O3-coated LUDOX-CL (ACS 20) with a primary particle size of 20 nm. In contrast, these particles caused a significant reduction of ATP levels and CFU. Fluorescence microscopy revealed that ACS 20 induced a pronounced agglomeration of the bacteria, which led to underestimated counts in regard of CFU. Bactericide effects as indicated by decreased ATP levels can be explained by bactericide additives that are present in the ACS 20 suspension.
Collapse
Affiliation(s)
- Julia Wehling
- Advanced Ceramics, University of Bremen, Am Biologischen Garten 2, 28359 Bremen, Germany
| | | | | | | | | | | | | |
Collapse
|
34
|
Leich E, Weißbach S, Klein HU, Grieb T, Pischimarov J, Stühmer T, Chatterjee M, Steinbrunn T, Langer C, Eilers M, Knop S, Einsele H, Bargou R, Rosenwald A. Multiple myeloma is affected by multiple and heterogeneous somatic mutations in adhesion- and receptor tyrosine kinase signaling molecules. Blood Cancer J 2013; 3:e102. [PMID: 23396385 PMCID: PMC3584721 DOI: 10.1038/bcj.2012.47] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Multiple myeloma (MM) is a largely incurable plasma cell malignancy with a poorly understood and heterogeneous clinical course. To identify potential, functionally relevant somatic mutations in MM, we performed whole-exome sequencing of five primary MM, corresponding germline DNA and six MM cell lines, and developed a bioinformatics strategy that also integrated published mutational data of 38 MM patients. Our analysis confirms that identical, recurrent mutations of single genes are infrequent in MM, but highlights that mutations cluster in important cellular pathways. Specifically, we show enrichment of mutations in adhesion molecules of MM cells, emphasizing the important role for the interaction of the MM cells with their microenvironment. We describe an increased rate of mutations in receptor tyrosine kinases (RTKs) and associated signaling effectors, for example, in EGFR, ERBB3, KRAS and MAP2K2, pointing to a role of aberrant RTK signaling in the development or progression of MM. The diversity of mutations affecting different nodes of a particular signaling network appears to be an intrinsic feature of individual MM samples, and the elucidation of intra- as well as interindividual redundancy in mutations that affect survival pathways will help to better tailor targeted therapeutic strategies to the specific needs of the MM patient.
Collapse
Affiliation(s)
- E Leich
- Institute of Pathology, University of Würzburg, Würzburg, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Kauko H, Grieb T, Bjørge R, Schowalter M, Munshi A, Weman H, Rosenauer A, van Helvoort A. Compositional characterization of GaAs/GaAsSb nanowires by quantitative HAADF-STEM. Micron 2013; 44:254-60. [DOI: 10.1016/j.micron.2012.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/10/2012] [Accepted: 07/10/2012] [Indexed: 10/28/2022]
|
36
|
Grieb T, Müller K, Fritz R, Schowalter M, Neugebohrn N, Knaub N, Volz K, Rosenauer A. Determination of the chemical composition of GaNAs using STEM HAADF imaging and STEM strain state analysis. Ultramicroscopy 2012; 117:15-23. [DOI: 10.1016/j.ultramic.2012.03.014] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/19/2012] [Accepted: 03/23/2012] [Indexed: 11/28/2022]
|
37
|
|
38
|
Grieb T, Kullmann W, Fehr P, Strobel K, Geick R. Ferromagnetic resonance in K2CuF4: magnetostatic modes, electromagnetic propagation effects and dependence of the anisotropy field on temperature and external magnetic field. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/17/36/035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|