1
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Mehdi E, Gundín M, Millet C, Somaschi N, Lemaître A, Sagnes I, Le Gratiet L, Fioretto DA, Belabas N, Krebs O, Senellart P, Lanco L. Giant optical polarisation rotations induced by a single quantum dot spin. Nat Commun 2024; 15:598. [PMID: 38238312 PMCID: PMC10796934 DOI: 10.1038/s41467-023-44651-8] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 12/27/2023] [Indexed: 01/22/2024] Open
Abstract
In the framework of optical quantum computing and communications, a major objective consists in building receiving nodes implementing conditional operations on incoming photons, using a single stationary qubit. In particular, the quest for scalable nodes motivated the development of cavity-enhanced spin-photon interfaces with solid-state emitters. An important challenge remains, however, to produce a stable, controllable, spin-dependent photon state, in a deterministic way. Here we use an electrically-contacted pillar-based cavity, embedding a single InGaAs quantum dot, to demonstrate giant polarisation rotations induced on reflected photons by a single electron spin. A complete tomography approach is introduced to extrapolate the output polarisation Stokes vector, conditioned by a specific spin state, in presence of spin and charge fluctuations. We experimentally approach polarisation states conditionally rotated by [Formula: see text], π, and [Formula: see text] in the Poincaré sphere with extrapolated fidelities of (97 ± 1) %, (84 ± 7) %, and (90 ± 8) %, respectively. We find that an enhanced light-matter coupling, together with limited cavity birefringence and reduced spectral fluctuations, allow targeting most conditional rotations in the Poincaré sphere, with a control both in longitude and latitude. Such polarisation control may prove crucial to adapt spin-photon interfaces to various configurations and protocols for quantum information.
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Affiliation(s)
- E Mehdi
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
- Université Paris Cité, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - M Gundín
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - C Millet
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - N Somaschi
- Quandela, 7 rue Leonard de Vinci, 91300, Massy, France
| | - A Lemaître
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - I Sagnes
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - L Le Gratiet
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - D A Fioretto
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
- Quandela, 7 rue Leonard de Vinci, 91300, Massy, France
| | - N Belabas
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - O Krebs
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - P Senellart
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France
| | - L Lanco
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France.
- Université Paris Cité, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France.
- Institut Universitaire de France (IUF), 75005, Paris, France.
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2
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Anders S, Steen A, Müller T, Krause W, Sanwald A, Raupach T, Ondruschka B, Krebs O. Adventure Legal Medicine: a free online serious game for supplementary use in undergraduate medical education. Int J Legal Med 2023; 137:545-549. [PMID: 36625885 PMCID: PMC9902303 DOI: 10.1007/s00414-023-02946-x] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 12/30/2022] [Indexed: 01/11/2023]
Abstract
Serious games (computer-based learning games) are increasingly used in medical education at various levels, as user access is independent of location and time and promotes non-linear learning. In legal medicine, interactive digital media are still scarce. The freely accessible online serious game "Adventure Legal Medicine" was developed as part of the "Hamburg Open Online University". The goal was to teach the basics of forensic casework in a point-and-click adventure setting consisting of five cases. During development, 40 medical students were asked to evaluate the game anonymously. The System Usability Scale (SUS) resulted in a mean score of 86.7 (SD 8.3), which corresponds to above-average usability. Further specific evaluations revealed a good to very good rating of the game with no differences in terms of gender (p = 0.214), first-year versus advanced students (p = 0.393) and students who never/rarely or sometimes/often played computer games (p = 0.780). Since there are only a few digital media so far that allow curricular integration into undergraduate teaching in legal medicine, this serious game represents a possibility to integrate digital media into both face-to-face teaching and distance learning and to use it as a supplement to the medical school's own teaching offer, encouraging users to actively engage with the subject.
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Affiliation(s)
- Sven Anders
- Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, 22529, Hamburg, Germany.
| | - Antonia Steen
- grid.13648.380000 0001 2180 3484Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany
| | - Tjark Müller
- grid.13648.380000 0001 2180 3484Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany ,grid.418956.70000 0004 0493 3318Leibniz-Institut Für Wissensmedien, Tübingen, Germany
| | - Waldemar Krause
- grid.13648.380000 0001 2180 3484Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany
| | - Annika Sanwald
- grid.13648.380000 0001 2180 3484Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany
| | - Tobias Raupach
- grid.15090.3d0000 0000 8786 803XDepartment of Medical Education, University Hospital Bonn, Bonn, Germany
| | - Benjamin Ondruschka
- grid.13648.380000 0001 2180 3484Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany
| | - Oliver Krebs
- grid.13648.380000 0001 2180 3484Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, 22529 Hamburg, Germany
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3
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Ollivier H, Priya P, Harouri A, Sagnes I, Lemaître A, Krebs O, Lanco L, Lanzillotti-Kimura ND, Esmann M, Senellart P. Three-Dimensional Electrical Control of the Excitonic Fine Structure for a Quantum Dot in a Cavity. Phys Rev Lett 2022; 129:057401. [PMID: 35960559 DOI: 10.1103/physrevlett.129.057401] [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] [Received: 12/01/2021] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
The excitonic fine structure plays a key role for the quantum light generated by semiconductor quantum dots, both for entangled photon pairs and single photons. Controlling the excitonic fine structure has been demonstrated using electric, magnetic, or strain fields, but not for quantum dots in optical cavities, a key requirement to obtain high source efficiency and near-unity photon indistinguishability. Here, we demonstrate the control of the fine structure splitting for quantum dots embedded in micropillar cavities. We propose and implement a scheme based on remote electrical contacts connected to the pillar cavity through narrow ridges. Numerical simulations show that such a geometry allows for a three-dimensional control of the electrical field. We experimentally demonstrate tuning and reproducible canceling of the fine structure, a crucial step for the reproducibility of quantum light source technology.
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Affiliation(s)
- H Ollivier
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - P Priya
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - A Harouri
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - I Sagnes
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - A Lemaître
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - O Krebs
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - L Lanco
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
- University Paris Cité, Centre de Nanosciences et de Nanotechnologies (C2N), 91120 Palaiseau, France
| | - N D Lanzillotti-Kimura
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - M Esmann
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - P Senellart
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies (C2N), 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
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4
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Thomas SE, Billard M, Coste N, Wein SC, Ollivier H, Krebs O, Tazaïrt L, Harouri A, Lemaitre A, Sagnes I, Anton C, Lanco L, Somaschi N, Loredo JC, Senellart P. Bright Polarized Single-Photon Source Based on a Linear Dipole. Phys Rev Lett 2021; 126:233601. [PMID: 34170172 DOI: 10.1103/physrevlett.126.233601] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/15/2021] [Accepted: 05/12/2021] [Indexed: 06/13/2023]
Abstract
Semiconductor quantum dots in cavities are promising single-photon sources. Here, we present a path to deterministic operation, by harnessing the intrinsic linear dipole in a neutral quantum dot via phonon-assisted excitation. This enables emission of fully polarized single photons, with a measured degree of linear polarization up to 0.994±0.007, and high population inversion-85% as high as resonant excitation. We demonstrate a single-photon source with a polarized first lens brightness of 0.50±0.01, a single-photon purity of 0.954±0.001, and single-photon indistinguishability of 0.909±0.004.
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Affiliation(s)
- S E Thomas
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - M Billard
- Quandela SAS, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - N Coste
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
- Quandela SAS, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - S C Wein
- Institute for Quantum Science and Technology and Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - H Ollivier
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - O Krebs
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - L Tazaïrt
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - A Harouri
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - A Lemaitre
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - I Sagnes
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - C Anton
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - L Lanco
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
- Université de Paris, Centre for Nanoscience and Nanotechnology (C2N), F-91120 Palaiseau, France
| | - N Somaschi
- Quandela SAS, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - J C Loredo
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - P Senellart
- Centre for Nanosciences and Nanotechnology, CNRS, Universite Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
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5
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Ollivier H, Thomas SE, Wein SC, de Buy Wenniger IM, Coste N, Loredo JC, Somaschi N, Harouri A, Lemaitre A, Sagnes I, Lanco L, Simon C, Anton C, Krebs O, Senellart P. Hong-Ou-Mandel Interference with Imperfect Single Photon Sources. Phys Rev Lett 2021; 126:063602. [PMID: 33635709 DOI: 10.1103/physrevlett.126.063602] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 10/08/2020] [Indexed: 06/12/2023]
Abstract
Hong-Ou-Mandel interference is a cornerstone of optical quantum technologies. We explore both theoretically and experimentally how unwanted multiphoton components of single-photon sources affect the interference visibility, and find that the overlap between the single photons and the noise photons significantly impacts the interference. We apply our approach to quantum dot single-photon sources to access the mean wave packet overlap of the single-photon component. This study provides a consistent platform with which to diagnose the limitations of current single-photon sources on the route towards the ideal device.
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Affiliation(s)
- H Ollivier
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - S E Thomas
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - S C Wein
- Institute for Quantum Science and Technology and Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - I Maillette de Buy Wenniger
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - N Coste
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - J C Loredo
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - N Somaschi
- Quandela SAS, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - A Harouri
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - A Lemaitre
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - I Sagnes
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - L Lanco
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
- Université Paris Diderot-Paris 7, 75205 Paris CEDEX 13, France
| | - C Simon
- Institute for Quantum Science and Technology and Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - C Anton
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - O Krebs
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
| | - P Senellart
- Centre for Nanosciences and Nanotechnology, CNRS, Université Paris-Saclay, UMR 9001, 10 Boulevard Thomas Gobert, 91120 Palaiseau, France
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6
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Mantripragada V, Carson E, Krebs O, Simmons H, Barnard J, Muschler G. Automated high throughput selection and expansion of clonal cell populations to improve cartilage cell therapy products. Cytotherapy 2020. [DOI: 10.1016/j.jcyt.2020.03.164] [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: 11/28/2022]
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7
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Edler C, Krebs O, Gehl A, Palatzke K, Tiedemann N, Schröder AS, Klein A. The effect of bleaching agents on the DNA analysis of bloodstains on different floor coverings. Int J Legal Med 2020; 134:921-927. [PMID: 31960151 DOI: 10.1007/s00414-020-02250-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 09/13/2019] [Accepted: 01/14/2020] [Indexed: 11/25/2022]
Abstract
Blood at crime scenes is one of the most significant traces of evidence in investigation proceedings. Cleaning up these traces with household cleaning products, often containing bleaching agents, inhibits or complicates the detection of DNA. In this study, human blood was applied onto different floor coverings (carpet, laminate, parquet, PVC, tile) and subsequently cleaned with water and bleaching agents (hydrogen peroxide, sodium hypochlorite, DanKlorix®, Vanish Oxi Action®) at different times. Samples have been collected afterwards from the floors. The samples underwent a quantitative and qualitative DNA analysis. Cleaning smooth surfaces with water is usually sufficed to prohibit retrieving a DNA profile in most of the cases. Cleaning carpets was more difficult due to their absorbent surface whereas the use of bleaching agents caused an additional reduction of verifiable DNA concentrations. Retrieving partial or complete profiles after the use of bleaching agents was only possible when cleaning with low concentrations of 3% hydrogen peroxide.
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Affiliation(s)
- C Edler
- Department of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | | | - A Gehl
- Department of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - K Palatzke
- Technical College of Applied Sciences, Police Academy Hamburg, Hamburg, Germany
| | - N Tiedemann
- Technical College of Applied Sciences, Police Academy Hamburg, Hamburg, Germany
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8
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Mansour H, Krebs O, Pinnschmidt HO, Griem N, Hammann-Ehrt I, Püschel K. Factors affecting dental DNA in various real post-mortem conditions. Int J Legal Med 2019; 133:1751-1759. [DOI: 10.1007/s00414-019-02151-9] [Citation(s) in RCA: 8] [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: 04/18/2019] [Accepted: 08/20/2019] [Indexed: 11/24/2022]
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9
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Mansour H, Sperhake JP, Bekaert B, Krebs O, Friedrich P, Fuhrmann A, Püschel K. New aspects of dental implants and DNA technology in human identification. Forensic Sci Int 2019; 302:109926. [PMID: 31444040 DOI: 10.1016/j.forsciint.2019.109926] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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: 04/08/2019] [Revised: 07/11/2019] [Accepted: 08/05/2019] [Indexed: 01/29/2023]
Abstract
Missing, ineligible or delayed reference data to establish conventional dental or DNA identification are common scenarios in forensic practice. Therefore, it is worthwhile to explore new avenues that facilitate human identification. Due to the recent remarkable evolution in the prosthetic dental restorations based on dental implants and the emergence of novel DNA technologies utilized to infer the biological profile, the identification process has become easier than ever before. We report on a characteristic case, which highlights the particular importance of dental implants and DNA approaches in the prospective investigations for human identification. The aim of this publication is to focus on the possibility of identifying the batch numbers, even if they were not engraved in dental implants, making antemortem dental records of dental implants more easily accessible to establish a comparative dental identification. In addition, the reported case presents the supplementary data yielded through estimating the epigenetic age using DNA methylation as well as the biogeographical origin using Y-Haplotype and mitochondrial DNA analyses. Our results demonstrate that expanded oral implant investigations that also include implants extraction and comprehensive microscopic measurements can lead to identifying their batch numbers despite the numerous number of implants systems manufactured and distributed worldwide. Data saved by dental implant manufacturers can be very supportive and represent additional reference data for dental identification, when antemortem dental records are still missing. Furthermore, DNA methylation and mitochondrial DNA analyses can support the progress of investigation.
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Affiliation(s)
- Hussam Mansour
- University Medical Center Hamburg-Eppendorf, Institute of Legal Medicine, Butenfeld34, 22529 Hamburg, Germany.
| | - Jan Peter Sperhake
- University Medical Center Hamburg-Eppendorf, Institute of Legal Medicine, Butenfeld34, 22529 Hamburg, Germany.
| | - Bram Bekaert
- KU Leuven - University of Leuven, Department of Imaging & Pathology, Campus St-Rafaël, Kapucijnenvoer 33, Leuven, Belgium; KU-Leuven - University of Leuven, University Hospitals Leuven, Department of Forensic Medicine, Laboratory of Forensic Genetics and Molecular Archeology, Campus St-Rafaël, Kapucijnenvoer 33, Leuven, Belgium.
| | - Oliver Krebs
- University Medical Center Hamburg-Eppendorf, Institute of Legal Medicine, Butenfeld34, 22529 Hamburg, Germany.
| | - Peter Friedrich
- State Criminal Investigation Department of the City of Hamburg (LKA 41), Bruno-Georges-Platz 1, 22297 Hamburg, Germany.
| | - Andreas Fuhrmann
- University Medical Center Hamburg-Eppendorf, Institute of Legal Medicine, Butenfeld34, 22529 Hamburg, Germany.
| | - Klaus Püschel
- University Medical Center Hamburg-Eppendorf, Institute of Legal Medicine, Butenfeld34, 22529 Hamburg, Germany.
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10
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Klein A, Krebs O, Gehl A, Morgner J, Reeger L, Augustin C, Edler C. The use of liquid latex for detecting traces of blood following thermal exposure. Int J Legal Med 2019; 133:1567-1574. [PMID: 31020398 DOI: 10.1007/s00414-019-02068-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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: 03/11/2019] [Accepted: 04/12/2019] [Indexed: 11/25/2022]
Abstract
In cases of crimes involving blood, the perpetrators often attempt to remove the traces they have left behind. Setting fire to the crime scene, aside from cleaning measures, seems to achieve this goal and presents a major challenge for crime scene investigators. There is only very little published information available on the effect of fire and extreme heat on blood and the detection thereof. After exposure to high temperatures of or exceeding 1.000 °C, blood is deemed to be undetectable. This study exposed 11 different potentially crime-relevant objects using a standardized and controlled procedure to temperatures of 300 °C, 700 °C, and 1.000 °C documenting the influence of heat on bloodstains and the detection of blood. The results of the forensic collection of blood traces with and without liquid latex confirmed the advantage of using the latex method. Almost all objects showed a clear luminescence-caused visualization of traces of blood after removing the soot with a latex lift. There were also fewer false positive results than in tests not using latex.
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Affiliation(s)
- Anke Klein
- Department of Legal Medicine, University Medical Center Hamburg-Eppendorf Institut für Rechtsmedizin, Universitätsklinik Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany.
| | - Oliver Krebs
- Department of Legal Medicine, University Medical Center Hamburg-Eppendorf Institut für Rechtsmedizin, Universitätsklinik Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany
| | - Axel Gehl
- Department of Legal Medicine, University Medical Center Hamburg-Eppendorf Institut für Rechtsmedizin, Universitätsklinik Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany
| | - Judith Morgner
- Technical College of Applied Sciences, Police Academy Hamburg, Fachhochschule der Polizeiakademie Hamburg, Hamburg, Germany
| | - Louisa Reeger
- Technical College of Applied Sciences, Police Academy Hamburg, Fachhochschule der Polizeiakademie Hamburg, Hamburg, Germany
| | - Christa Augustin
- Department of Legal Medicine, University Medical Center Hamburg-Eppendorf Institut für Rechtsmedizin, Universitätsklinik Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany
| | - Carolin Edler
- Department of Legal Medicine, University Medical Center Hamburg-Eppendorf Institut für Rechtsmedizin, Universitätsklinik Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany
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11
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12
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Edler C, Gehl A, Kohwagner J, Walther M, Krebs O, Augustin C, Klein A. Erratum to: Blood Trace Evidence on Washed Textiles - a systematic approach. Int J Legal Med 2017; 131:1191. [PMID: 28275858 DOI: 10.1007/s00414-017-1569-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Carolin Edler
- Department of Legal Medicine, University of Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany.
| | - A Gehl
- Department of Legal Medicine, University of Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany
| | - J Kohwagner
- Authority for Interior and Sport, Hamburg, Germany
| | - M Walther
- Authority for Interior and Sport, Hamburg, Germany
| | - O Krebs
- Department of Legal Medicine, University of Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany
| | - C Augustin
- Department of Legal Medicine, University of Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany
| | - A Klein
- Department of Legal Medicine, University of Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany
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Edler C, Gehl A, Kohwagner J, Walther M, Krebs O, Augustin C, Klein A. Blood Trace Evidence on Washed Textiles - a systematic approach. Int J Legal Med 2017; 131:1179-1189. [DOI: 10.1007/s00414-017-1549-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 01/24/2017] [Indexed: 11/24/2022]
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14
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Jopp-van Well E, Gehl A, Säring D, Amling M, Hahn M, Sperhake J, Augustin C, Krebs O, Püschel K. [Reconstructive investigations and identification measures in unknown soldiers of the Second World War]. Arch Kriminol 2016; 237:153-171. [PMID: 27386620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The article reports on the exhumation and identification of unknown soldiers from the Second World War. With the help of medicolegal investigation and reconstruction methods an American pilot presumably murdered by a shot to the head (lynch law) and an interned Italian soldier could be identified after about 70 years and brought back home.
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15
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Bäuerle L, Kanitz U, Laurich S, Naumovska K, Fröb D, Krebs O, Wilkens A, Püschell K. [Myiasis because of neglect]. Arch Kriminol 2014; 234:183-192. [PMID: 26548020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Myiasis is known as the infestation of living organisms with maggots. It is often caused by (self-) neglect. Eight cases of myiasis have been examined at the Institute of Legal Medicine in Hamburg between 2002 and 2014. It is important that the medical examiner compares the maggots' stage of development with the alleged time of death. Especially in cases of home care, myiasis and neglect are suspicious and deserve special attention.
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Jopp E, Püschel K, Warschke C, Kaufmann R, Krebs O. [Identification of an exhumed unknown infant through DNA analysis]. Arch Kriminol 2014; 233:203-209. [PMID: 25004622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The article reports on the exhumation and subsequent DNA analysis of the skeletal remains of an unknown male newborn from 1988. Molecular biological methods confirmed the maternity of a woman who was already convicted of infanticide. Since homicide could not be clearly proven and manslaughter becomes barred by the statute of limitation after 20 years, the woman cannot be held accountable for the alleged killing of her first child.
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Sallen G, Kunz S, Amand T, Bouet L, Kuroda T, Mano T, Paget D, Krebs O, Marie X, Sakoda K, Urbaszek B. Nuclear magnetization in gallium arsenide quantum dots at zero magnetic field. Nat Commun 2014; 5:3268. [PMID: 24500329 PMCID: PMC3926008 DOI: 10.1038/ncomms4268] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [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] [Received: 09/11/2013] [Accepted: 01/16/2014] [Indexed: 11/09/2022] Open
Abstract
Optical and electrical control of the nuclear spin system allows enhancing the sensitivity of NMR applications and spin-based information storage and processing. Dynamic nuclear polarization in semiconductors is commonly achieved in the presence of a stabilizing external magnetic field. Here we report efficient optical pumping of nuclear spins at zero magnetic field in strain-free GaAs quantum dots. The strong interaction of a single, optically injected electron spin with the nuclear spins acts as a stabilizing, effective magnetic field (Knight field) on the nuclei. We optically tune the Knight field amplitude and direction. In combination with a small transverse magnetic field, we are able to control the longitudinal and transverse components of the nuclear spin polarization in the absence of lattice strain--that is, in dots with strongly reduced static nuclear quadrupole effects, as reproduced by our model calculations.
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Affiliation(s)
- G Sallen
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - S Kunz
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - T Amand
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - L Bouet
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - T Kuroda
- National Institute for Material Science, Namiki 1-1, Tsukuba 305-0044, Japan
| | - T Mano
- National Institute for Material Science, Namiki 1-1, Tsukuba 305-0044, Japan
| | - D Paget
- LPMC, Ecole Polytechnique, CNRS, 91128 Palaiseau, France
| | - O Krebs
- CNRS Laboratoire de Photonique et de Nanostructures, Route de Nozay, 91460 Marcoussis, France
| | - X Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
| | - K Sakoda
- National Institute for Material Science, Namiki 1-1, Tsukuba 305-0044, Japan
| | - B Urbaszek
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France
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18
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Püschel K, Jopp E, Gehl A, Krebs O, Paradowski I, Fuhrmann A, Yamamura J, Karul M, Stöckel U, Bär J, Germer R. „Fake“ aus Norddeutschland statt ägyptischer Mumie. Rechtsmedizin (Berl) 2013. [DOI: 10.1007/s00194-013-0925-2] [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: 11/30/2022]
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19
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Krebs O, Lemaître A. Optically induced coupling of two magnetic dopant spins by a photoexcited hole in a Mn-doped InAs/GaAs quantum dot. Phys Rev Lett 2013; 111:187401. [PMID: 24237560 DOI: 10.1103/physrevlett.111.187401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/06/2013] [Indexed: 06/02/2023]
Abstract
We report evidence of a photoinduced coupling between two spins provided by Mn dopants in their neutral acceptor state A(0) in a single InAs/GaAs quantum dot. The coupling occurs due to simultaneous exchange interactions between each of the two dopant spins and a photocreated hole. Microphotoluminescence spectroscopy achieved both in longitudinal and perpendicular magnetic fields reveals the splitting of the four spin configurations |J(1) = ± 1,J(2) = ± 1} due to the 2A(0)-hole exchange interaction. We obtain a comprehensive interpretation of the experimental data with a simplified spin Hamiltonian model, which more specifically shows that the hole-mediated coupling is similar to a ε(12)-70 μeV exchange interaction between both A(0) spins.
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Affiliation(s)
- O Krebs
- CNRS-Laboratoire de Photonique et de Nanostructures, Route de Nozay, 91460 Marcoussis, France
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20
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Loo V, Arnold C, Gazzano O, Lemaître A, Sagnes I, Krebs O, Voisin P, Senellart P, Lanco L. Optical nonlinearity for few-photon pulses on a quantum dot-pillar cavity device. Phys Rev Lett 2012; 109:166806. [PMID: 23215114 DOI: 10.1103/physrevlett.109.166806] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Indexed: 06/01/2023]
Abstract
Giant optical nonlinearity is observed under both continuous wave and pulsed excitation in a deterministically coupled quantum dot-micropillar system, in a pronounced strong-coupling regime. Using absolute reflectivity measurements we determine the critical intracavity photon number as well as the input and output coupling efficiencies of the device. Thanks to a near-unity input-coupling efficiency, we demonstrate a record nonlinearity threshold of only 8 incident photons per pulse. The output-coupling efficiency is found to strongly influence this nonlinearity threshold. We show how the fundamental limit of single-photon nonlinearity can be attained in realistic devices, which would provide an effective interaction between two coincident single-photons.
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Affiliation(s)
- V Loo
- Laboratoire de Photonique et Nanostructures, LPN/CNRS, Route de Nozay, 91460 Marcoussis, France
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21
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Baudin E, Benjamin E, Lemaître A, Krebs O. Optical pumping and a nondestructive readout of a single magnetic impurity spin in an InAs/GaAs quantum dot. Phys Rev Lett 2011; 107:197402. [PMID: 22181643 DOI: 10.1103/physrevlett.107.197402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Indexed: 05/31/2023]
Abstract
We report on the resonant optical pumping of the | ± 1⟩ spin states of a single Mn dopant in an InAs/GaAs quantum dot which is embedded in a charge tunable device. The experiment relies on a W scheme of transitions reached when a suitable longitudinal magnetic field is applied. The optical pumping is achieved via the resonant excitation of the central Λ system at the neutral exciton X(0) energy. For a specific gate voltage, the redshifted photoluminescence of the charged exciton X- is observed, which allows a nondestructive readout of the spin polarization. An arbitrary spin preparation in the | + 1⟩ or |-1⟩ state characterized by a polarization near or above 50% is evidenced.
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Affiliation(s)
- E Baudin
- CNRS-Laboratoire de Photonique et de Nanostructures, Route de Nozay, 91460 Marcoussis, France
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22
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Wolstencroft K, Owen S, Horridge M, Krebs O, Mueller W, Snoep JL, du Preez F, Goble C. RightField: embedding ontology annotation in spreadsheets. Bioinformatics 2011; 27:2021-2. [DOI: 10.1093/bioinformatics/btr312] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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23
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Simon CM, Belhadj T, Chatel B, Amand T, Renucci P, Lemaitre A, Krebs O, Dalgarno PA, Warburton RJ, Marie X, Urbaszek B. Robust quantum dot exciton generation via adiabatic passage with frequency-swept optical pulses. Phys Rev Lett 2011; 106:166801. [PMID: 21599394 DOI: 10.1103/physrevlett.106.166801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 03/09/2011] [Indexed: 05/30/2023]
Abstract
The energy states in semiconductor quantum dots are discrete as in atoms, and quantum states can be coherently controlled with resonant laser pulses. Long coherence times allow the observation of Rabi flopping of a single dipole transition in a solid state device, for which occupancy of the upper state depends sensitively on the dipole moment and the excitation laser power. We report on the robust population inversion in a single quantum dot using an optical technique that exploits rapid adiabatic passage from the ground to an excited state through excitation with laser pulses whose frequency is swept through the resonance. This observation in photoluminescence experiments is made possible by introducing a novel optical detection scheme for the resonant electron hole pair (exciton) generation.
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Affiliation(s)
- C-M Simon
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, Toulouse, France
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24
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Krebs O, Maletinsky P, Amand T, Urbaszek B, Lemaître A, Voisin P, Marie X, Imamoglu A. Anomalous Hanle effect due to optically created transverse overhauser field in single InAs/GaAs quantum dots. Phys Rev Lett 2010; 104:056603. [PMID: 20366781 DOI: 10.1103/physrevlett.104.056603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Indexed: 05/29/2023]
Abstract
We report on experimental observations of an anomalous Hanle effect in individual self-assembled InAs/GaAs quantum dots. A sizable electron spin polarization photocreated under constant illumination is maintained in transverse magnetic fields as high as approximately 1 T, up to a critical field where it abruptly collapses. These striking anomalies of the Hanle curve point to a novel mechanism of dynamic nuclear spin polarization giving rise to an effective magnetic field generated perpendicular to the optically injected electron spin polarization. This transverse Overhauser field, confirmed by the cancellation of electron Zeeman splitting below the critical field, is likely to be a consequence of the strong inhomogeneous quadrupolar interactions typical for strained quantum dots.
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Affiliation(s)
- O Krebs
- CNRS-Laboratoire de Photonique et de Nanostructures, Route de Nozay, 91460 Marcoussis, France
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Kudelski A, Lemaître A, Miard A, Voisin P, Graham TCM, Warburton RJ, Krebs O. Optically probing the fine structure of a single Mn atom in an InAs quantum dot. Phys Rev Lett 2007; 99:247209. [PMID: 18233484 DOI: 10.1103/physrevlett.99.247209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Indexed: 05/25/2023]
Abstract
We report on the optical spectroscopy of a single InAs/GaAs quantum dot doped with a single Mn atom in a longitudinal magnetic field of a few Tesla. Our findings show that the Mn impurity is a neutral acceptor state A0 whose effective spin J=1 is significantly perturbed by the quantum dot potential and its associated strain field. The spin interaction with photocarriers injected in the quantum dot is shown to be ferromagnetic for holes, with an effective coupling constant of a few hundreds of mueV, but vanishingly small for electrons.
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Affiliation(s)
- A Kudelski
- Laboratoire de Photonique et Nanostructures-CNRS, Route de Nozay, 91460 Marcoussis, France
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Kowalik K, Krebs O, Senellart P, Lemaître A, Eble B, Kudelski A, Gaj J, Voisin P. Stark spectroscopy of Coulomb interactions in individual InAs/GaAs self-assembled quantum dots. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/pssc.200671598] [Citation(s) in RCA: 12] [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: 11/06/2022]
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Laurent S, Eble B, Krebs O, Lemaître A, Urbaszek B, Marie X, Amand T, Voisin P. Electrical control of hole spin relaxation in charge tunable InAs/GaAs quantum dots. Phys Rev Lett 2005; 94:147401. [PMID: 15904109 DOI: 10.1103/physrevlett.94.147401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Indexed: 05/02/2023]
Abstract
We report on optical orientation of singly charged excitons (trions) in charge-tunable self-assembled InAs/GaAs quantum dots. When the charge varies from 0 to -2, the trion photoluminescence of a single quantum dot shows up and under quasiresonant excitation gets progressively polarized from zero to approximately 100%. This behavior is interpreted as the electric control of the trion thermalization process, which subsequently acts on the hole-spin relaxation driven in nanosecond time scale by the anisotropic electron-hole exchange. This is supported by the excitation spectroscopy and time-resolved measurements of a quantum dot ensemble.
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Affiliation(s)
- S Laurent
- CNRS-Laboratoire de Photonique et Nanostructures, Route de Nozay, 91460 Marcoussis, France
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28
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Braun PF, Marie X, Lombez L, Urbaszek B, Amand T, Renucci P, Kalevich VK, Kavokin KV, Krebs O, Voisin P, Masumoto Y. Direct observation of the electron spin relaxation induced by nuclei in quantum dots. Phys Rev Lett 2005; 94:116601. [PMID: 15903877 DOI: 10.1103/physrevlett.94.116601] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Revised: 12/17/2004] [Indexed: 05/02/2023]
Abstract
We have studied the electron spin relaxation in semiconductor InAs/GaAs quantum dots by time-resolved optical spectroscopy. The average spin polarization of the electrons in an ensemble of p-doped quantum dots decays down to 1/3 of its initial value with a characteristic time T(Delta) approximately 500 ps, which is attributed to the hyperfine interaction with randomly oriented nuclear spins. We show that this efficient electron spin relaxation mechanism can be suppressed by an external magnetic field as small as 100 mT.
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Affiliation(s)
- P-F Braun
- LNMO, INSA 135 Avenue de Rangueil, 31077 Toulouse CEDEX 4, France
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Abstract
[structure: see text] A strategy for the synthesis of ajudazol A, an unusual, pharmacologically active metabolite from myxobacteria, based on the Stille cross-coupling of a 2-stannyl-oxazole with a vinyl iodide unit is described; the vinyl halide unit containing a (Z,Z)-diene was prepared in one pot by the double acetylene carbocupration of a functionalized alkyl cuprate followed by trapping with 2,3-dibromopropene.
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Affiliation(s)
- Oliver Krebs
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
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Laurent S, Krebs O, Sénès M, Marie X, Amand T, Voisin P, Gérard JM. Counter polarized photoluminescence of trions in n-doped selfassembled InAs/GaAs quantumdots. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/pssc.200304023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Adam W, Krebs O. The Nitroso Ene Reaction: A Regioselective and Stereoselective Allylic Nitrogen Functionalization of Mechanistic Delight and Synthetic Potential. Chem Rev 2003; 103:4131-46. [PMID: 14531720 DOI: 10.1021/cr030004x] [Citation(s) in RCA: 209] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Waldemar Adam
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
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Adam W, Krebs O, Orfanopoulos M, Stratakis M, Vougioukalakis GC. Intramolecular and intermolecular kinetic isotope effects (KIE) in the nitrosoarene ene reaction: experimental evidence for reversible intermediate formation. J Org Chem 2003; 68:2420-5. [PMID: 12636411 DOI: 10.1021/jo0266240] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The intramolecular and intermolecular kinetic isotope effects (KIE) have been determined for the nitrosoarene ene reaction with deuterium-stereolabeled 2,3-dimethyl-2-butenes (TME). trans-TME-d(6) (k(H)/k(D) = 3.0) and gem-TME-d(6) (k(H)/k(D) = 4.0) show large intramolecular primary isotope effects. In contrast, the intramolecular competition in cis-TME-d(6) (k(H)/k(D) = 1.5) and the intermolecular competition for the TME-d(0)/TME-d(12) pair (k(H)/k(D) = 1.98) show considerably smaller, but mechanistically significant kinetic isotope effects. The latter fact is rationalized in terms of reversible formation of a three-membered-ring intermediate, namely the aziridine N-oxide, or a similar unsymmetrical, polarized diradical in the first step of the reaction. Such reversibility has also been implied earlier for triazolinedione (TAD) and singlet oxygen ((1)O(2)) with deuterium-stereolabeled 2-butenes, but of the three enophiles, ArNO is the most sensitive toward reversibility, which is due to its moderate reactivity and its high steric demand.
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Affiliation(s)
- Waldemar Adam
- Institut für Organische Chemie, Universität Würzburg, Am Hubland D-97074 Würzburg, Germany.
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Stratakis M, Nencka R, Rabalakos C, Adam W, Krebs O. Thionin-sensitized intrazeolite photooxygenation of trisubstituted alkenes: substituent effects on the regioselectivity as probed through isotopic labeling. J Org Chem 2002; 67:8758-63. [PMID: 12467386 DOI: 10.1021/jo020350z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The regioselectivity for the intrazeolite photooxygenation of several trisubstituted alkenes with geminal dimethyl groups was examined. The length of the alkyl chain at the lone position was varied, and as end groups, the phenyl or the cyclohexyl functionalities were chosen. The general trend for all alkenes is a significant increase of the reactivity at the twin position compared to the photooxygenation in solution. For the cyclohexyl-substituted alkenes, it was found that the regioselectivity is nearly independent of the alkyl chain length. However, for the phenyl-substituted alkenes, the ene reactivity of the allylic methylene hydrogen atoms at the lone position and the twix/twin regioselectivity depend significantly on the distance of the phenyl group from the double bond. These trends are discussed in terms of cation-pi interactions and conformational effects. Intramolecular and intermolecular isotope effects in the intrazeolite photooxygenation of deuterium-labeled alkenes suggest that a perepoxide-type intermediate is formed in the rate-determining step. Type I photooxygenation that involves reaction of the radical cations of the alkenes with superoxide ion are unlikely.
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Affiliation(s)
- Manolis Stratakis
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, Germany
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35
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Adam W, Bottke N, Krebs O, Lykakis I, Orfanopoulos M, Stratakis M. Ene reaction of singlet oxygen, triazolinedione, and nitrosoarene with chiral deuterium-labeled allylic alcohols: the interdependence of diastereoselectivity and regioselectivity discloses mechanistic insights into the hydroxy-group directivity. J Am Chem Soc 2002; 124:14403-9. [PMID: 12452715 DOI: 10.1021/ja027800p] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ene reaction of singlet oxygen ((1)O(2)), triazolinedione (TAD), and nitrosoarene, specifically 4-nitronitrosobenzene (ArNO), with the tetrasubstituted 1,3-allylically strained, chiral allylic alcohol 3,4-dimethylpent-3-en-2-ol (2) leads to the threo-configured ene products in high diastereoselectivity, a consequence of the hydroxy-group directivity. Hydrogen bonding favors formation of the threo-configured encounter complex threo-EC in the early stage of ene reaction. For the analogous twix deuterium-labeled allylic alcohol Z-2-d(3), a hitherto unrecognized dichotomy between (1)O(2) and the ArNO and TAD enophiles is disclosed in the regioselectivity of the tetrasubstituted alcohol: Whereas for ArNO and TAD, hydrogen bonding with the allylic hydroxy group dictates the regioselectivity (twix selectivity), for (1)O(2), the cis effect dominates (twin/trix selectivity). From the interdependence between the twix/twin regioselectivity and the threo/erythro diastereoselectivity, it has been recognized that the enophile also attacks the allylic alcohol from the erythro pi face without assistance by hydrogen bonding with the allylic hydroxy functionality.
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Affiliation(s)
- Waldemar Adam
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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36
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Adam W, Bosio S, Degen HG, Krebs O, Stalke D, Schumacher D. A Comparative Study on the Diastereofacial Control in the [4+2] Cycloaddition of Sorbates and the Ene Reaction of Tiglates with Singlet Oxygen and PTAD by a Variety of Chiral Auxiliaries. European J Org Chem 2002. [DOI: 10.1002/1099-0690(200212)2002:23<3944::aid-ejoc3944>3.0.co;2-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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37
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Adam W, Krebs O, Orfanopoulos M, Stratakis M. Control of regioselectivity by the lone substituent through steric and electronic effects in the nitrosoarene ene reaction of deuterium-labeled trisubstituted alkenes. J Org Chem 2002; 67:8395-9. [PMID: 12444616 DOI: 10.1021/jo026198i] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
For the ene reaction of 4-nitronitrosobenzene (ArNO) with a variety of primary and secondary lone alkyl-substituted substrates, the twix/twin regioselectivity is constant at about 85:15. In contrast, for the lone tert-butyl group and for lone aryl substituents, the twix regioisomer is obtained exclusively. These regioselectivities have been rationalized in terms of steric interactions and coordination between the enophile and the substrates in the transition states of the first reaction step.
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Affiliation(s)
- Waldemar Adam
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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Cortez S, Krebs O, Laurent S, Senes M, Marie X, Voisin P, Ferreira R, Bastard G, Gérard JM, Amand T. Optically driven spin memory in n-doped InAs-GaAs quantum dots. Phys Rev Lett 2002; 89:207401. [PMID: 12443505 DOI: 10.1103/physrevlett.89.207401] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2002] [Indexed: 05/24/2023]
Abstract
We show that the spin state of the resident electron in an n-doped self-assembled InAs-GaAs quantum dot can be written and read using nonresonant, circularly polarized optical pumping. A simple theoretical model is presented and accounts for the remarkable dynamics producing counterpolarized photoluminescence.
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Affiliation(s)
- S Cortez
- Laboratoire de Physique de la Matière Condensée de l'Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France
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Adam W, Degen HG, Krebs O, Saha-Möller CR. Efficient pi-facial control in the ene reaction of nitrosoarene, triazolinedione, and singlet oxygen with tiglic amides of the bornane-derived sultam as chiral auxiliary: an economical synthesis of enantiomerically pure nitrogen- and oxygen-functionalized acrylic acid derivatives. J Am Chem Soc 2002; 124:12938-9. [PMID: 12405807 DOI: 10.1021/ja026640e] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ene reaction of 4-nitronitrosobenzene (ArNO), N-phenyl-1,2,4-triazoline-3,5-dione (PTAD), and singlet oxygen (1O2) with the optically active tiglic-acid derivatives of Oppolzer's bornane-derived sultam affords the respective ene products regioselectively in excellent diastereoselectivity (de up to 99%) and in good yield (55-90%). The enophiles ArNO and PTAD give with the methyl-substituted substrate exclusively the like-configured ene adduct, while 1O2 leads to an 83:17 diastereomeric mixture. With the sterically more demanding isopropyl-substituted derivative even the smallest enophile 1O2 forms exclusively the like diastereomer. The high diastereoselectivity is rationalized in terms of the proper conformational alignment of the substrate and a preferred enophilic attack from the C(beta)-re face of the double bond. This concept offers an efficient synthetic route to enantiomerically pure nitrogen- and oxygen-functionalized acrylic acid derivatives.
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Affiliation(s)
- Waldemar Adam
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Jiang Z, Rottmann OJ, Krebs O, Chen J, Liu H, Pirchner F. A missense mutation in the follicle stimulating hormone receptor (FSHR) gene shows different allele effects on litter size in Chinese Erhualian and German Landrace pigs. J Anim Breed Genet 2002. [DOI: 10.1046/j.1439-0388.2002.00354.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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41
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Schneider MR, Zhou R, Hoeflich A, Krebs O, Schmidt J, Mohan S, Wolf E, Lahm H. Insulin-like growth factor-binding protein-5 inhibits growth and induces differentiation of mouse osteosarcoma cells. Biochem Biophys Res Commun 2001; 288:435-42. [PMID: 11606061 DOI: 10.1006/bbrc.2001.5785] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The precise role of insulin-like growth factor-binding protein-5 (IGFBP-5) in regulating the growth of tumor cells, especially of bone-derived malignant cells, is not well understood. We have investigated the biological activity of IGFBP-5 by transfecting OS/50-K8 mouse osteosarcoma cells with an expression vector containing the osteocalcin promoter and the complete mouse IGFBP-5 cDNA (OC-IGFBP-5). Overexpression of IGFBP-5 mRNA and secretion of increased amounts of bioactive protein in conditioned media were demonstrated in different clones. For the analysis of cell proliferation, three clones exhibiting high levels of IGFBP-5 expression were selected and compared to a mock clone and to nontransfected parental cells. IGFBP-5-secreting clones displayed reduced proliferation under both anchorage-dependent and -independent conditions (P < 0.05). The increase in proliferation observed in IGFBP-5-secreting clones after addition of exogenous IGF was significantly lower than that observed in mock-transfected or parental cells. A similar result was obtained with long[R3]IGF-I which has a low affinity for all IGFBPs, suggesting that the inhibitory effect of IGFBP-5 is only partially IGF-dependent. OC-IGFBP-5-transfected clones expressed significantly higher amounts of osteocalcin mRNA (P < 0.05) and secreted more osteocalcin protein than a mock clone or parental OS-50/K8 cells. Thus, part of the growth-inhibiting effect of IGFBP-5 may be due to an induction of differentiation in these cells.
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Affiliation(s)
- M R Schneider
- Institute of Molecular Animal Breeding, Gene Center of the Ludwig-Maximilian University, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany.
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Adam W, Bottke N, Engels B, Krebs O. An experimental and computational study on the reactivity and regioselectivity for the nitrosoarene ene reaction: comparison with triazolinedione and singlet oxygen. J Am Chem Soc 2001; 123:5542-8. [PMID: 11389637 DOI: 10.1021/ja004356m] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The regioselectivities and the reactivities (relative rates) for the ene reaction of the enophile 4-nitronitrosobenzene (ArNO) with an extensive set of regiochemically defined acyclic and cyclic olefins have been determined. These experimental data establish that the ArNO enophile attacks the olefinic substrate along the novel skew trajectory, with preferred hydrogen abstraction at the corner (twix regioselectivity). This is in contrast to the isoelectronic species singlet oxygen ((1)O(2)), which abstracts at the higher substituted side of the double-bond (cis effect), and triazolindione (TAD), which undergoes the ene reaction at the more crowded end (gem effect). Ab initio computations (B3LYP/6-31+g) for the ene reaction of the ArNO with 2-methyl-2-butene reveal that the steric effects between the aryl group of the enophile and the substituents of the olefin dictate the skew trajectory. These computations identify the aziridine N-oxide (AI) as a bona fide intermediate in this ene reaction, whose formation is usually rate-determining and, thus, irreversible along the skew trajectory (twix selectivity). The reversible generation of the AI becomes feasible when conformational constraints outweigh steric effects, as manifested by enhanced twin regioselectivity.
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Affiliation(s)
- W Adam
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Prelle K, Wobus AM, Krebs O, Blum WF, Wolf E. Overexpression of insulin-like growth factor-II in mouse embryonic stem cells promotes myogenic differentiation. Biochem Biophys Res Commun 2000; 277:631-8. [PMID: 11062005 DOI: 10.1006/bbrc.2000.3737] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Embryonic stem (ES) cells derived from androgenetic or parthenogenetic mouse embryos are important tools for studying the roles of imprinted genes in early development. Androgenetic ES cells have been shown to preferentially differentiate into the myogenic lineage both in vitro and after formation of teratocarcinomas in vivo. To clarify if the maternally imprinted Igf2 gene which is expected to be overexpressed in androgenetic ES cells is sufficient to induce myogenic differentiation, R1 ES cells were transfected with human IGF-II expression vectors. Stable ES cell clones exhibiting human IGF-II mRNA and protein expression were studied vs ES cell clones without IGF-II overexpression in a standard in vitro differentiation system involving culture in "hanging drops" and observation of differentiation of the recovered embryoid bodies (EBs). EBs derived from IGF-II overexpressing ES cells showed stimulated myogenic differentiation evident by the appearance of myoblasts already 3 days after plating and by higher levels of skeletal muscle-specific transcripts (myf5, myoD, myogenin) at earlier stages. Our study demonstrates for the first time that overexpression of IGF-II enhances and accelerates myogenic differentiation of ES cells, which has implications for ES cell-derived tissue engineering.
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Affiliation(s)
- K Prelle
- Department of Molecular Animal Breeding and Genetics, Ludwig-Maximilian University, Feodor-Lynen-Strasse 25, Munich, Germany
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Rathkolb B, Fuchs E, Kolb HJ, Renner-Müller I, Krebs O, Balling R, Hrabé de Angelis M, Wolf E. Large-scale N-ethyl-N-nitrosourea mutagenesis of mice--from phenotypes to genes. Exp Physiol 2000; 85:635-44. [PMID: 11187959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
The most important tool for obtaining insight into the function of genes is the use of mutant model organisms. Homologous recombination in embryonic stem cells allows the systematic production of mouse mutants for any gene that has been cloned. Gene trap strategies have been designed to interrupt even unknown genes which are tagged by the inserted vector and can be characterised structurally and functionally. Complementary to such 'gene-driven' approaches, 'phenotype-driven' approaches are necessary to identify new genes or gene products through a search for mutants with specific defects, uncovering the function of genetic pathways in physiological and pathological processes. Mutagenesis using the alkylating agent N-ethyl-N-nitrosourea (ENU) is a powerful approach for the production of such mouse mutants. Since ENU induces mainly point mutations in premeiotic spermatogonia, this strategy allows the production of multiple alleles of a particular gene, which is pivotal for a fine tuned analysis of its function.
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Affiliation(s)
- B Rathkolb
- Institute of Molecular Animal Breeding, Gene Centre, Ludwig-Maximilian University, Munich, Germany
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Adam W, Bottke N, Krebs O. The New skew and the Established cis and gem Regioselectivities in the Ene Reaction of Trisubstituted Olefins: Comparison of the Singlet Oxygen, Triazolinedione, and Nitrosoarene Enophiles. J Am Chem Soc 2000. [DOI: 10.1021/ja994523m] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Waldemar Adam
- Institut für Organische Chemie, Universität Würzburg Am Hubland, D-97074 Würzburg, Germany
| | - Nils Bottke
- Institut für Organische Chemie, Universität Würzburg Am Hubland, D-97074 Würzburg, Germany
| | - Oliver Krebs
- Institut für Organische Chemie, Universität Würzburg Am Hubland, D-97074 Würzburg, Germany
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Fassy F, Krebs O, Rey H, Komara B, Gillard C, Capdevila C, Yea C, Faucheu C, Blanchet AM, Miossec C, Diu-Hercend A. Enzymatic activity of two caspases related to interleukin-1beta-converting enzyme. Eur J Biochem 1998; 253:76-83. [PMID: 9578463 DOI: 10.1046/j.1432-1327.1998.2530076.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Interleukin-1beta-converting enzyme is a member of a family of human cysteine proteases with specificity for aspartic acid, which have been named caspases. Within this family of enzymes, transcript X (TX) and transcript Y (TY) (caspases 4 and 5, respectively) are very similar to ICE (caspase 1) and form the ICE subfamily. Given the high degree of conservation in the sequences of these proteases (more than 50% amino acid identity in the mature enzymes), it was of interest to examine whether they shared similar substrate specificities. The three enzymes, ICE, TX and TY, were therefore expressed in baculovirus-infected insect cells, as 30-kDa proteins lacking the propeptide. Automaturation into p20 and p10 subunits occurred within the cells. Active ICE, TX and TY were collected in the cell culture supernatants. In addition, their production induced the activation of an endogenous 32-kDa putative cysteine protease (CPP32) like caspase. T7-tagged ICE, TX and TY were purified by immunoaffinity and tested for their catalytic efficiency on YVAD-containing synthetic substrates and on the ICE natural substrate, pro-interleukin-1beta. TX cleaved the same synthetic substrates as ICE (Km of 90 microM and k(cat) of 0.4 s(-1) for Suc-YVAD-NH-Mec, where Suc represents succinyl and NH-Mec represents amino-4-methylcoumarin) and could cleave pro-interleukin-1beta into the same peptides as ICE but less efficiently. On the other hand, TY showed very little efficacy on the different ICE substrates (Km of 860 microM for Suc-YVAD-NH-Mec). These results show that the ICE/TX/TY subfamily has functional heterogeneity and that ICE remains the preferred enzyme for pro-interleukin-1beta cleavage.
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Affiliation(s)
- F Fassy
- Hoechst Marion Roussel, Romainville, France.
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Krebs O, Schäfer B, Wolff T, Oesterle D, Deml E, Sund M, Favor J. The DNA damaging drug cyproterone acetate causes gene mutations and induces glutathione-S-transferase P in the liver of female Big Blue transgenic F344 rats. Carcinogenesis 1998; 19:241-5. [PMID: 9498271 DOI: 10.1093/carcin/19.2.241] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The gestagenic and antiandrogenic drug cyproterone acetate (CPA) is mitogenic, tumorigenic and induces DNA-adducts and DNA-repair synthesis in rat liver. Thus CPA is expected to be mutagenic. However in vitro mutagenicity test systems were negative. To examine whether CPA induces mutations in rat liver, the in vivo mutation assay based on Big Blue transgenic F344 rats was employed. Single oral doses of 25, 50, 75, 100 and 200 mg CPA/kg b.w. respectively were administered to female Big Blue rats. Six weeks after treatment, liver DNA was assayed for mutations. At the highest dose, 200 mg CPA/kg b.w., the frequency of (17 +/- 4) x 10(-6) spontaneous mutations was increased to a maximum of (80 +/- 8) x 10(-6) mutations. One-hundred and 75 mg CPA/kg b.w. resulted in mutation frequencies of (35 +/- 5) and (27 +/- 5) x 10(-6), respectively. The mutation frequency at doses of 50 and 25 mg CPA/kg b.w. was similar to that of vehicle treated controls. Statistical analysis of the dose-effect relationship revealed that it was not possible to decide whether a threshold dose exists or not. DNA adducts were analyzed by the 32P-postlabelling technique. The total level of the major and the two minor adducts observed in the autoradiograms increased between doses of 25 to 75 mg CPA/kg b.w. to a maximum of approximately 12,000 +/- 3000 adducts per 10(9) nucleotides. The level did not further increase significantly with 100 and 200 mg CPA/kg b.w. After CPA treatment no preneoplastic liver foci were observed. However, single glutathione-S-transferase placental form (GST-P) positive hepatocytes were observed and the frequency was dependent on the dose. These cells are not supposed to represent initiated cells, since they occurred only transiently after 6 weeks and disappeared thereafter completely. In conclusion, our results demonstrate that CPA is mutagenic in vivo. The mutation frequency increased at high CPA doses, when the increase of the DNA adduct formation had already ceased. This suggests that the mitogenic activity of CPA is required to express the mutations.
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Affiliation(s)
- O Krebs
- Institute of Molecular Animal Breeding, Gene Center, Ludwig-Maximilians-Universität, München, Germany.
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Abstract
The transgenic Muta Mouse in vivo mutagenesis assay was employed to determine the activity of acrylamide and ethylnitrosourea in liver and germ cells after 3, 10 and 100 days following treatment. Each cell of the Muta Mouse carries 80 copies of the lambda gt10 phage including the bacterial lacZ gene, which act as the target gene for the mutagenesis assay. Groups of Muta Mice were given a single intraperitoneal injection of 80 or 160 mg/kg ethylnitrosourea or 50 or 100 mg/kg acrylamide. The tissues were prepared 3, 10 or 100 days post treatment. The liver genomic DNA was extracted with the manufacturer's standard protocol, while the genomic germ cell DNA was extracted with 4 different methods due to problems encountered in DNA yields and packaging efficiency. The mutation analysis of the lacZ gene was carried out by the positive selective assay method [Gossen et al. (1989) Proc. Natl. Acad. Sci. USA, 86, 7971-7975; Dean and Myhr (1994) Mutagenesis, 9, 183-185]. There was a slight increase due to treatment of the observed mutation frequencies in the acrylamide liver group for all three assay times. From the day 3 group to the day 100 group a time dependent decrease in all the absolute mutant frequencies was detectable. The ethylnitrosourea liver group showed a time- and dose-dependent increase in the mutant frequencies from day 3 to day 100. No meaningful results were obtained for the germ cell tissue assays due to the low amount of genomic DNA extracted which was not packageable in the lambda lacZ assay. At present for the mutagenesis assay of isolated spermatozoa in our laboratory we would be forced to pool tissues from animals to obtain enough DNA for an assay. Since 'jackpot'-animals may exist [Heddle et al. (1992) Mutation Res., 272, 195-203] the individual animals of such a pooled analysis group must be tested before pooling.
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Affiliation(s)
- O Krebs
- Institut für Säugetiergenetik, GSF-Forschungszentrum für Umweli und Gesundheit, Oberschleissheim, Germany
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Krebs O, Voisin P. Giant Optical Anisotropy of Semiconductor Heterostructures with No Common Atom and the Quantum-Confined Pockels Effect. Phys Rev Lett 1996; 77:1829-1832. [PMID: 10063182 DOI: 10.1103/physrevlett.77.1829] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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