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Wang Q, Pan M, Kreiss L, Samaei S, Carp SA, Johansson JD, Zhang Y, Wu M, Horstmeyer R, Diop M, Li DDU. A comprehensive overview of diffuse correlation spectroscopy: Theoretical framework, recent advances in hardware, analysis, and applications. Neuroimage 2024; 298:120793. [PMID: 39153520 DOI: 10.1016/j.neuroimage.2024.120793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2024] [Revised: 07/23/2024] [Accepted: 08/14/2024] [Indexed: 08/19/2024] Open
Abstract
Diffuse correlation spectroscopy (DCS) is a powerful tool for assessing microvascular hemodynamic in deep tissues. Recent advances in sensors, lasers, and deep learning have further boosted the development of new DCS methods. However, newcomers might feel overwhelmed, not only by the already-complex DCS theoretical framework but also by the broad range of component options and system architectures. To facilitate new entry to this exciting field, we present a comprehensive review of DCS hardware architectures (continuous-wave, frequency-domain, and time-domain) and summarize corresponding theoretical models. Further, we discuss new applications of highly integrated silicon single-photon avalanche diode (SPAD) sensors in DCS, compare SPADs with existing sensors, and review other components (lasers, sensors, and correlators), as well as data analysis tools, including deep learning. Potential applications in medical diagnosis are discussed and an outlook for the future directions is provided, to offer effective guidance to embark on DCS research.
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Affiliation(s)
- Quan Wang
- Department of Biomedical Engineering, Faculty of Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Mingliang Pan
- Department of Biomedical Engineering, Faculty of Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Lucas Kreiss
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Saeed Samaei
- Department of Medical and Biophysics, Schulich School of Medical & Dentistry, Western University, London, Ontario, Canada; Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
| | - Stefan A Carp
- Massachusetts General Hospital, Optics at Athinoula A. Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, MA, United States
| | | | - Yuanzhe Zhang
- Department of Biomedical Engineering, Faculty of Engineering, University of Strathclyde, Glasgow, United Kingdom
| | - Melissa Wu
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Roarke Horstmeyer
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Mamadou Diop
- Department of Medical and Biophysics, Schulich School of Medical & Dentistry, Western University, London, Ontario, Canada; Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
| | - David Day-Uei Li
- Department of Biomedical Engineering, Faculty of Engineering, University of Strathclyde, Glasgow, United Kingdom.
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Hsu CC, Yeh CL, Lee WK, Hsu HT, Shyu KK, Li LPH, Wu TY, Lee PL. Extraction of high-frequency SSVEP for BCI control using iterative filtering based empirical mode decomposition. Biomed Signal Process Control 2020. [DOI: 10.1016/j.bspc.2020.102022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Towards a Pragmatic Approach to a Psychophysiological Unit of Analysis for Mental and Brain Disorders: An EEG-Copeia for Neurofeedback. Appl Psychophysiol Biofeedback 2020; 44:151-172. [PMID: 31098793 DOI: 10.1007/s10484-019-09440-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This article proposes what we call an "EEG-Copeia" for neurofeedback, like the "Pharmacopeia" for psychopharmacology. This paper proposes to define an "EEG-Copeia" as an organized list of scientifically validated EEG markers, characterized by a specific association with an identified cognitive process, that define a psychophysiological unit of analysis useful for mental or brain disorder evaluation and treatment. A characteristic of EEG neurofeedback for mental and brain disorders is that it targets a EEG markers related to a supposed cognitive process, whereas conventional treatments target clinical manifestations. This could explain why EEG neurofeedback studies encounter difficulty in achieving reproducibility and validation. The present paper suggests that a first step to optimize EEG neurofeedback protocols and future research is to target a valid EEG marker. The specificity of the cognitive skills trained and learned during real time feedback of the EEG marker could be enhanced and both the reliability of neurofeedback training and the therapeutic impact optimized. However, several of the most well-known EEG markers have seldom been applied for neurofeedback. Moreover, we lack a reliable and valid EEG targets library for further RCT to evaluate the efficacy of neurofeedback in mental and brain disorders. With the present manuscript, our aim is to foster dialogues between cognitive neuroscience and EEG neurofeedback according to a psychophysiological perspective. The primary objective of this review was to identify the most robust EEG target. EEG markers linked with one or several clearly identified cognitive-related processes will be identified. The secondary objective was to organize these EEG markers and related cognitive process in a psychophysiological unit of analysis matrix inspired by the Research Domain Criteria (RDoC) project.
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Trauer SM, Müller MM, Kotz SA. Expectation Gates Neural Facilitation of Emotional Words in Early Visual Areas. Front Hum Neurosci 2019; 13:281. [PMID: 31507390 PMCID: PMC6716056 DOI: 10.3389/fnhum.2019.00281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 07/30/2019] [Indexed: 11/13/2022] Open
Abstract
The current study examined whether emotional expectations gate attention to emotional words in early visual cortex. Color cues informed about word valence and onset latency. We observed a stimulus-preceding negativity prior to the onset of cued words that was larger for negative than for neutral words. This indicates that in anticipation of emotional words more attention was allocated to them than to neutral words before target onset. During stimulus presentation the steady-state visual evoked potential (SSVEP), elicited by flickering words, was attenuated for cued compared to uncued words, indicating sharpened sensory activity, i.e., expectation suppression. Most importantly, the SSVEP was more enhanced for negative than neutral words when these were cued. Uncued conditions did not differ in SSVEP amplitudes, paralleling previous studies reporting lexico-semantic but not early visual effects of emotional words. We suggest that cueing mediates re-entrant engagement of visual resources by providing an early “affective gist” of an upcoming word. Consequently, visual single-word studies may have underestimated attentional effects of emotional words and their anticipation during reading.
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Affiliation(s)
- Sophie M Trauer
- Lehrstuhl für Allgemeine Psychologie, Institut für Psychologie, Universität Leipzig, Leipzig, Germany
| | - Matthias M Müller
- Lehrstuhl für Allgemeine Psychologie, Institut für Psychologie, Universität Leipzig, Leipzig, Germany
| | - Sonja A Kotz
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands.,Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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Montani V, Chanoine V, Stoianov IP, Grainger J, Ziegler JC. Steady state visual evoked potentials in reading aloud: Effects of lexicality, frequency and orthographic familiarity. BRAIN AND LANGUAGE 2019; 192:1-14. [PMID: 30826643 DOI: 10.1016/j.bandl.2019.01.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/16/2018] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
The present study explored the possibility to use Steady-State Visual Evoked Potentials (SSVEPs) as a tool to investigate the core mechanisms in visual word recognition. In particular, we investigated three benchmark effects of reading aloud: lexicality (words vs. pseudowords), frequency (high-frequency vs. low-frequency words), and orthographic familiarity ('familiar' versus 'unfamiliar' pseudowords). We found that words and pseudowords elicited robust SSVEPs. Words showed larger SSVEPs than pseudowords and high-frequency words showed larger SSVEPs than low-frequency words. SSVEPs were not sensitive to orthographic familiarity. We further localized the neural generators of the SSVEP effects. The lexicality effect was located in areas associated with early level of visual processing, i.e. in the right occipital lobe and in the right precuneus. Pseudowords produced more activation than words in left sensorimotor areas, rolandic operculum, insula, supramarginal gyrus and in the right temporal gyrus. These areas are devoted to speech processing and/or spelling-to-sound conversion. The frequency effect involved the left temporal pole and orbitofrontal cortex, areas previously implicated in semantic processing and stimulus-response associations respectively, and the right postcentral and parietal inferior gyri, possibly indicating the involvement of the right attentional network.
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Affiliation(s)
- Veronica Montani
- Aix-Marseille University and CNRS, Brain and Language Research Institute, 3 Place Victor Hugo, 13331 Marseille Cedex 3, France.
| | - Valerie Chanoine
- Aix-Marseille University, Institute of Language, Communication and the Brain, Brain and Language Research Institute, 13100 Aix-en-Provence, France
| | - Ivilin Peev Stoianov
- Aix-Marseille University and CNRS, LPC, 3 Place Victor Hugo, 13331 Marseille Cedex 3, France; Institute of Cognitive Sciences and Technologies, CNR, Via Martiri della Libertà 2, 35137 Padova, Italy
| | - Jonathan Grainger
- Aix-Marseille University and CNRS, LPC, 3 Place Victor Hugo, 13331 Marseille Cedex 3, France
| | - Johannes C Ziegler
- Aix-Marseille University and CNRS, LPC, 3 Place Victor Hugo, 13331 Marseille Cedex 3, France
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Kuś R, Spustek T, Zieleniewska M, Duszyk A, Rogowski P, Suffczyński P. Integrated trimodal SSEP experimental setup for visual, auditory and tactile stimulation. J Neural Eng 2017; 14:066002. [PMID: 28786397 DOI: 10.1088/1741-2552/aa836f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Steady-state evoked potentials (SSEPs), the brain responses to repetitive stimulation, are commonly used in both clinical practice and scientific research. Particular brain mechanisms underlying SSEPs in different modalities (i.e. visual, auditory and tactile) are very complex and still not completely understood. Each response has distinct resonant frequencies and exhibits a particular brain topography. Moreover, the topography can be frequency-dependent, as in case of auditory potentials. However, to study each modality separately and also to investigate multisensory interactions through multimodal experiments, a proper experimental setup appears to be of critical importance. The aim of this study was to design and evaluate a novel SSEP experimental setup providing a repetitive stimulation in three different modalities (visual, tactile and auditory) with a precise control of stimuli parameters. Results from a pilot study with a stimulation in a particular modality and in two modalities simultaneously prove the feasibility of the device to study SSEP phenomenon. APPROACH We developed a setup of three separate stimulators that allows for a precise generation of repetitive stimuli. Besides sequential stimulation in a particular modality, parallel stimulation in up to three different modalities can be delivered. Stimulus in each modality is characterized by a stimulation frequency and a waveform (sine or square wave). We also present a novel methodology for the analysis of SSEPs. MAIN RESULTS Apart from constructing the experimental setup, we conducted a pilot study with both sequential and simultaneous stimulation paradigms. EEG signals recorded during this study were analyzed with advanced methodology based on spatial filtering and adaptive approximation, followed by statistical evaluation. SIGNIFICANCE We developed a novel experimental setup for performing SSEP experiments. In this sense our study continues the ongoing research in this field. On the other hand, the described setup along with the presented methodology is a considerable improvement and an extension of methods constituting the state-of-the-art in the related field. Device flexibility both with developed analysis methodology can lead to further development of diagnostic methods and provide deeper insight into information processing in the human brain.
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Affiliation(s)
- Rafał Kuś
- Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
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Trauer SM, Kotz SA, Müller MM. Emotional words facilitate lexical but not early visual processing. BMC Neurosci 2015; 16:89. [PMID: 26654384 PMCID: PMC4676879 DOI: 10.1186/s12868-015-0225-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 11/24/2015] [Indexed: 12/30/2022] Open
Abstract
Background Emotional scenes and faces have shown to capture and bind visual resources at early sensory processing stages, i.e. in early visual cortex. However, emotional words have led to mixed results. In the current study ERPs were assessed simultaneously with steady-state visual evoked potentials (SSVEPs) to measure attention effects on early visual activity in emotional word processing. Neutral and negative words were flickered at 12.14 Hz whilst participants performed a Lexical Decision Task. Results Emotional word content did not modulate the 12.14 Hz SSVEP amplitude, neither did word lexicality. However, emotional words affected the ERP. Negative compared to neutral words as well as words compared to pseudowords lead to enhanced deflections in the P2 time range indicative of lexico-semantic access. The N400 was reduced for negative compared to neutral words and enhanced for pseudowords compared to words indicating facilitated semantic processing of emotional words. LPC amplitudes reflected word lexicality and thus the task-relevant response. Conclusion In line with previous ERP and imaging evidence, the present results indicate that written emotional words are facilitated in processing only subsequent to visual analysis.
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Affiliation(s)
- Sophie M Trauer
- Lehrstuhl für Allgemeine Psychologie, Institut für Psychologie, Universität Leipzig, Neumarkt 9-19, 04109, Leipzig, Germany.
| | - Sonja A Kotz
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands. .,Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Matthias M Müller
- Lehrstuhl für Allgemeine Psychologie, Institut für Psychologie, Universität Leipzig, Neumarkt 9-19, 04109, Leipzig, Germany.
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Farzam P, Durduran T. Multidistance diffuse correlation spectroscopy for simultaneous estimation of blood flow index and optical properties. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:55001. [PMID: 25938205 DOI: 10.1117/1.jbo.20.5.055001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Accepted: 03/31/2015] [Indexed: 05/19/2023]
Abstract
Traditionally, diffuse correlation spectroscopy (DCS) measures microvascular blood flow by fitting a physical model to the measurement of the intensity autocorrelation function from a single source-detector pair. This analysis relies on the accurate knowledge of the optical properties, absorption, and reduced scattering coefficients of the medium. Therefore, DCS is often deployed together with diffuse optical spectroscopy. We present an algorithm that employs multidistance DCS (MD-DCS) for simultaneous measurement of bloodflow index, as well as an estimate of the optical properties of the tissue. The algorithm has been validated through noise-free and noise-added simulated data and phantom measurements. A longitudinal in vivo measurement ofa mouse tumor is also shown. MD-DCS is introduced as a stand-alone system for small source-detector separations (<2 cm) for noninvasive measurement of microvascular blood flow.
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Mesquita RC, Durduran T, Yu G, Buckley EM, Kim MN, Zhou C, Choe R, Sunar U, Yodh AG. Direct measurement of tissue blood flow and metabolism with diffuse optics. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:4390-406. [PMID: 22006897 PMCID: PMC3263785 DOI: 10.1098/rsta.2011.0232] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Diffuse optics has proven useful for quantitative assessment of tissue oxy- and deoxyhaemoglobin concentrations and, more recently, for measurement of microvascular blood flow. In this paper, we focus on the flow monitoring technique: diffuse correlation spectroscopy (DCS). Representative clinical and pre-clinical studies from our laboratory illustrate the potential of DCS. Validation of DCS blood flow indices in human brain and muscle is presented. Comparison of DCS with arterial spin-labelled MRI, xenon-CT and Doppler ultrasound shows good agreement (0.50<r<0.95) over a wide range of tissue types and source detector distances, corroborating the potential of the method to measure perfusion non-invasively and in vivo at the microvasculature level. All-optical measurements of cerebral oxygen metabolism in both rat brain, following middle cerebral artery occlusion, and human brain, during functional activation, are also described. In both situations, the use of combined DCS and diffuse optical spectroscopy/near-infrared spectroscopy to monitor changes in oxygen consumption by the tissue is demonstrated. Finally, recent results spanning from gene expression-induced angiogenic response to stroke care and cancer treatment monitoring are discussed. Collectively, the research illustrates the capability of DCS to quantitatively monitor perfusion from bench to bedside, providing results that match up both with literature findings and with similar experiments performed with other techniques.
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Affiliation(s)
- Rickson C Mesquita
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Irwin D, Dong L, Shang Y, Cheng R, Kudrimoti M, Stevens SD, Yu G. Influences of tissue absorption and scattering on diffuse correlation spectroscopy blood flow measurements. BIOMEDICAL OPTICS EXPRESS 2011; 2:1969-85. [PMID: 21750773 PMCID: PMC3130582 DOI: 10.1364/boe.2.001969] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 06/13/2011] [Accepted: 06/14/2011] [Indexed: 05/19/2023]
Abstract
In this study we evaluate the influences of optical property assumptions on near-infrared diffuse correlation spectroscopy (DCS) flow index measurements. The optical properties, absorption coefficient (µ(a)) and reduced scattering coefficient (µ(s)'), are independently varied using liquid phantoms and measured concurrently with the flow index using a hybrid optical system combining a dual-wavelength DCS flow device with a commercial frequency-domain tissue-oximeter. DCS flow indices are calculated at two wavelengths (785 and 830 nm) using measured µ(a) and µ(s)' or assumed constant µ(a) and µ(s)'. Inaccurate µ(s)' assumptions resulted in much greater flow index errors than inaccurate µ(a). Underestimated/overestimated µ(s)' from -35%/+175% lead to flow index errors of +110%/-80%, whereas underestimated/overestimated µ(a) from -40%/+150% lead to -20%/+40%, regardless of the wavelengths used. Examination of a clinical study involving human head and neck tumors indicates up to +280% flow index errors resulted from inter-patient optical property variations. These findings suggest that studies involving significant µ(a) and µ(s)' changes should concurrently measure flow index and optical properties for accurate extraction of blood flow information.
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Affiliation(s)
- Daniel Irwin
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Lixin Dong
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Yu Shang
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Ran Cheng
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Mahesh Kudrimoti
- Department of Radiation Medicine, University of Kentucky Chandler Hospital, Lexington, KY 40536, USA
| | - Scott D. Stevens
- Department of Radiology, University of Kentucky Chandler Hospital, Lexington, KY 40536, USA
| | - Guoqiang Yu
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
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Ninck M, Untenberger M, Gisler T. Diffusing-wave spectroscopy with dynamic contrast variation: disentangling the effects of blood flow and extravascular tissue shearing on signals from deep tissue. BIOMEDICAL OPTICS EXPRESS 2010; 1:1502-1513. [PMID: 21258565 PMCID: PMC3018123 DOI: 10.1364/boe.1.001502] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/12/2010] [Accepted: 11/20/2010] [Indexed: 05/19/2023]
Abstract
We investigate the effects of blood flow and extravascular tissue shearing on diffusing-wave spectroscopy (DWS) signals from deep tissue, using an ex vivo porcine kidney model perfused artificially at controlled arterial pressure and flow. Temporal autocorrelation functions g((1))(τ) of the multiply scattered light field show a decay which is described by diffusion for constant flow, with a diffusion coefficient scaling linearly with volume flow rate. Replacing blood by a non-scattering fluid reveals a flow-independent background dynamics of the extravascular tissue. For a sinusoidally driven perfusion, field autocorrelation functions g((1))(τ, t') depend on the phase t' within the pulsation cycle and are approximately described by diffusion. The effective diffusion coefficient D(eff)(t') is modulated at the driving frequency in the presence of blood, showing coupling with flow rate; in the absence of blood, D(eff)(t') is modulated at twice the driving frequency, indicating shearing of extravascular tissue as the origin of the DWS signal. For both constant and pulsatile flow the contribution of extravascular tissue shearing to the DWS signal is small.
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Affiliation(s)
- Markus Ninck
- Universität Konstanz, Fachbereich Physik, 78457 Konstanz, Germany
| | | | - Thomas Gisler
- Universität Konstanz, Fachbereich Physik, 78457 Konstanz, Germany
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