1
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Katkat E, Demirci Y, Heger G, Karagulle D, Papatheodorou I, Brazma A, Ozhan G. Canonical Wnt and TGF-β/BMP signaling enhance melanocyte regeneration but suppress invasiveness, migration, and proliferation of melanoma cells. Front Cell Dev Biol 2023; 11:1297910. [PMID: 38020918 PMCID: PMC10679360 DOI: 10.3389/fcell.2023.1297910] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 09/20/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023] Open
Abstract
Melanoma is the deadliest form of skin cancer and develops from the melanocytes that are responsible for the pigmentation of the skin. The skin is also a highly regenerative organ, harboring a pool of undifferentiated melanocyte stem cells that proliferate and differentiate into mature melanocytes during regenerative processes in the adult. Melanoma and melanocyte regeneration share remarkable cellular features, including activation of cell proliferation and migration. Yet, melanoma considerably differs from the regenerating melanocytes with respect to abnormal proliferation, invasive growth, and metastasis. Thus, it is likely that at the cellular level, melanoma resembles early stages of melanocyte regeneration with increased proliferation but separates from the later melanocyte regeneration stages due to reduced proliferation and enhanced differentiation. Here, by exploiting the zebrafish melanocytes that can efficiently regenerate and be induced to undergo malignant melanoma, we unravel the transcriptome profiles of the regenerating melanocytes during early and late regeneration and the melanocytic nevi and malignant melanoma. Our global comparison of the gene expression profiles of melanocyte regeneration and nevi/melanoma uncovers the opposite regulation of a substantial number of genes related to Wnt signaling and transforming growth factor beta (TGF-β)/(bone morphogenetic protein) BMP signaling pathways between regeneration and cancer. Functional activation of canonical Wnt or TGF-β/BMP pathways during melanocyte regeneration promoted melanocyte regeneration but potently suppressed the invasiveness, migration, and proliferation of human melanoma cells in vitro and in vivo. Therefore, the opposite regulation of signaling mechanisms between melanocyte regeneration and melanoma can be exploited to stop tumor growth and develop new anti-cancer therapies.
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Affiliation(s)
- Esra Katkat
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Izmir, Türkiye
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Izmir, Türkiye
| | - Yeliz Demirci
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Izmir, Türkiye
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Izmir, Türkiye
| | | | - Doga Karagulle
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Izmir, Türkiye
- Department of Molecular Biology and Genetics, Izmir Institute of Technology, Izmir, Türkiye
| | - Irene Papatheodorou
- European Molecular Biology Laboratory—European Bioinformatics Institute (EMBL-EBI), Cambridge, United Kingdom
| | - Alvis Brazma
- European Molecular Biology Laboratory—European Bioinformatics Institute (EMBL-EBI), Cambridge, United Kingdom
| | - Gunes Ozhan
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Izmir, Türkiye
- Department of Molecular Biology and Genetics, Izmir Institute of Technology, Izmir, Türkiye
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2
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Azbazdar Y, Demirci Y, Heger G, Ipekgil D, Karabicici M, Ozhan G. Comparative membrane lipidomics of hepatocellular carcinoma cells reveals diacylglycerol and ceramide as key regulators of Wnt/β-catenin signaling and tumor growth. Mol Oncol 2023; 17:2314-2336. [PMID: 37699867 PMCID: PMC10620124 DOI: 10.1002/1878-0261.13520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 08/22/2023] [Accepted: 09/09/2023] [Indexed: 09/14/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is largely associated with aberrant activation of Wnt/β-catenin signaling. Nevertheless, how membrane lipid composition is altered in HCC cells with abnormal Wnt signaling remains elusive. Here, by exploiting comprehensive lipidome profiling, we unravel the membrane lipid composition of six different HCC cell lines with mutations in components of Wnt/β-catenin signaling, leading to differences in their endogenous signaling activity. Among the differentially regulated lipids are diacylglycerol (DAG) and ceramide, which were downregulated at the membrane of HCC cells after Wnt3a treatment. DAG and ceramide enhanced Wnt/β-catenin signaling by inducing caveolin-mediated endocytosis of the canonical Wnt-receptor complex, while their depletion suppressed the signaling activity along with a reduction of caveolin-mediated endocytosis in SNU475 and HepG2 cells. Moreover, depletion of DAG and ceramide significantly impeded the proliferation, tumor growth, and in vivo migration capacity of SNU475 and HepG2 cells. This study, by pioneering plasma membrane lipidome profiling in HCC cells, exhibits the remarkable potential of lipids to correct dysregulated signaling pathways in cancer and stop abnormal tumor growth.
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Affiliation(s)
- Yagmur Azbazdar
- Izmir Biomedicine and Genome Center (IBG)Dokuz Eylul University Health CampusIzmirTurkey
- Izmir International Biomedicine and Genome Institute (IBG‐Izmir)Dokuz Eylul UniversityIzmirTurkey
- Present address:
Department of Biological ChemistryUniversity of California Los AngelesCAUSA
| | - Yeliz Demirci
- Izmir Biomedicine and Genome Center (IBG)Dokuz Eylul University Health CampusIzmirTurkey
- Izmir International Biomedicine and Genome Institute (IBG‐Izmir)Dokuz Eylul UniversityIzmirTurkey
- Present address:
Wellcome Sanger InstituteCambridgeUK
| | | | - Dogac Ipekgil
- Izmir Biomedicine and Genome Center (IBG)Dokuz Eylul University Health CampusIzmirTurkey
- Izmir International Biomedicine and Genome Institute (IBG‐Izmir)Dokuz Eylul UniversityIzmirTurkey
| | - Mustafa Karabicici
- Izmir Biomedicine and Genome Center (IBG)Dokuz Eylul University Health CampusIzmirTurkey
- Izmir International Biomedicine and Genome Institute (IBG‐Izmir)Dokuz Eylul UniversityIzmirTurkey
- Present address:
Board of Governors Regenerative Medicine InstituteCedars‐Sinai Medical CenterLos AngelesCAUSA
| | - Gunes Ozhan
- Izmir Biomedicine and Genome Center (IBG)Dokuz Eylul University Health CampusIzmirTurkey
- Izmir International Biomedicine and Genome Institute (IBG‐Izmir)Dokuz Eylul UniversityIzmirTurkey
- Present address:
Department of Molecular Biology and GeneticsIzmir Institute of TechnologyTurkey
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3
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Mishra M, Barck L, Moreno P, Heger G, Song Y, Thornton JM, Papatheodorou I. SelectBCM tool: a batch evaluation framework to select the most appropriate batch-correction methods for bulk transcriptome analysis. NAR Genom Bioinform 2023; 5:lqad014. [PMID: 36879900 PMCID: PMC9985330 DOI: 10.1093/nargab/lqad014] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 01/11/2023] [Accepted: 03/02/2023] [Indexed: 03/07/2023] Open
Abstract
Bulk transcriptomes are an essential data resource for understanding basic and disease biology. However, integrating information from different experiments remains challenging because of the batch effect generated by various technological and biological variations in the transcriptome. Numerous batch-correction methods to deal with this batch effect have been developed in the past. However, a user-friendly workflow to select the most appropriate batch-correction method for the given set of experiments is still missing. We present the SelectBCM tool that prioritizes the most appropriate batch-correction method for a given set of bulk transcriptomic experiments, improving biological clustering and gene differential expression analysis. We demonstrate the applicability of the SelectBCM tool on analyses of real data for two common diseases, rheumatoid arthritis and osteoarthritis, and one example to characterize a biological state, where we performed a meta-analysis of the macrophage activation state. The R package is available at https://github.com/ebi-gene-expression-group/selectBCM.
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Affiliation(s)
- Madhulika Mishra
- European Molecular Biology Laboratory, European Bioinformatics Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK.,GSK, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Lucas Barck
- European Molecular Biology Laboratory, European Bioinformatics Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK.,Open Targets, Welcome Genome Campus, Hinxton, Cambridge CB10 1SD, UK.,GSK, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Pablo Moreno
- European Molecular Biology Laboratory, European Bioinformatics Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK.,GSK, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Guillaume Heger
- European Molecular Biology Laboratory, European Bioinformatics Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK.,Heidelberg University, Grabengasse 1, 69117 Heidelberg, Germany
| | - Yuyao Song
- European Molecular Biology Laboratory, European Bioinformatics Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Janet M Thornton
- European Molecular Biology Laboratory, European Bioinformatics Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK.,GSK, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
| | - Irene Papatheodorou
- European Molecular Biology Laboratory, European Bioinformatics Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK.,GSK, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, UK
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4
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Von Stumm M, Illig J, Heger G, Wolf CM, Ewert P, Hörer J, Cleuziou J. Double-Outlet Right Ventricle Fallot Type versus Tetralogy of Fallot: Comparison of Native Anatomy, Surgical Patterns, and Outcomes. Thorac Cardiovasc Surg 2023. [DOI: 10.1055/s-0043-1761745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2023]
Affiliation(s)
- M. Von Stumm
- Deutsches Herzzentrum München, München, Deutschland
| | - J. Illig
- Deutsches Herzzentrum München, München, Deutschland
| | - G. Heger
- Deutsches Herzzentrum München, München, Deutschland
| | - C. M. Wolf
- Deutsches Herzzentrum München, München, Deutschland
| | - P. Ewert
- Deutsches Herzzentrum München, München, Deutschland
| | - J. Hörer
- Deutsches Herzzentrum München, München, Deutschland
| | - J. Cleuziou
- Deutsches Herzzentrum München, München, Deutschland
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5
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Demirci Y, Heger G, Katkat E, Papatheodorou I, Brazma A, Ozhan G. Brain Regeneration Resembles Brain Cancer at Its Early Wound Healing Stage and Diverges From Cancer Later at Its Proliferation and Differentiation Stages. Front Cell Dev Biol 2022; 10:813314. [PMID: 35223842 PMCID: PMC8868567 DOI: 10.3389/fcell.2022.813314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 01/18/2022] [Indexed: 12/15/2022] Open
Abstract
Gliomas are the most frequent type of brain cancers and characterized by continuous proliferation, inflammation, angiogenesis, invasion and dedifferentiation, which are also among the initiator and sustaining factors of brain regeneration during restoration of tissue integrity and function. Thus, brain regeneration and brain cancer should share more molecular mechanisms at early stages of regeneration where cell proliferation dominates. However, the mechanisms could diverge later when the regenerative response terminates, while cancer cells sustain proliferation. To test this hypothesis, we exploited the adult zebrafish that, in contrast to the mammals, can efficiently regenerate the brain in response to injury. By comparing transcriptome profiles of the regenerating zebrafish telencephalon at its three different stages, i.e., 1 day post-lesion (dpl)-early wound healing stage, 3 dpl-early proliferative stage and 14 dpl-differentiation stage, to those of two brain cancers, i.e., low-grade glioma (LGG) and glioblastoma (GBM), we reveal the common and distinct molecular mechanisms of brain regeneration and brain cancer. While the transcriptomes of 1 dpl and 3 dpl harbor unique gene modules and gene expression profiles that are more divergent from the control, the transcriptome of 14 dpl converges to that of the control. Next, by functional analysis of the transcriptomes of brain regeneration stages to LGG and GBM, we reveal the common and distinct molecular pathways in regeneration and cancer. 1 dpl and LGG and GBM resemble with regard to signaling pathways related to metabolism and neurogenesis, while 3 dpl and LGG and GBM share pathways that control cell proliferation and differentiation. On the other hand, 14 dpl and LGG and GBM converge with respect to developmental and morphogenetic processes. Finally, our global comparison of gene expression profiles of three brain regeneration stages, LGG and GBM exhibit that 1 dpl is the most similar stage to LGG and GBM while 14 dpl is the most distant stage to both brain cancers. Therefore, early convergence and later divergence of brain regeneration and brain cancer constitutes a key starting point in comparative understanding of cellular and molecular events between the two phenomena and development of relevant targeted therapies for brain cancers.
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Affiliation(s)
- Yeliz Demirci
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, Izmir, Turkey
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Inciralti-Balcova, Izmir, Turkey
- Wellcome Sanger Institute, Hinxton, United Kingdom
| | | | - Esra Katkat
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, Izmir, Turkey
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Inciralti-Balcova, Izmir, Turkey
| | - Irene Papatheodorou
- European Molecular Biology Laboratory–European Bioinformatics Institute (EMBL-EBI), Cambridge, United Kingdom
| | - Alvis Brazma
- European Molecular Biology Laboratory–European Bioinformatics Institute (EMBL-EBI), Cambridge, United Kingdom
| | - Gunes Ozhan
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University Health Campus, Inciralti-Balcova, Izmir, Turkey
- Izmir International Biomedicine and Genome Institute (IBG-Izmir), Dokuz Eylul University, Inciralti-Balcova, Izmir, Turkey
- *Correspondence: Gunes Ozhan,
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6
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Demirci Y, Cucun G, Poyraz YK, Mohammed S, Heger G, Papatheodorou I, Ozhan G. Comparative Transcriptome Analysis of the Regenerating Zebrafish Telencephalon Unravels a Resource With Key Pathways During Two Early Stages and Activation of Wnt/β-Catenin Signaling at the Early Wound Healing Stage. Front Cell Dev Biol 2020; 8:584604. [PMID: 33163496 PMCID: PMC7581945 DOI: 10.3389/fcell.2020.584604] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 09/11/2020] [Indexed: 01/22/2023] Open
Abstract
Owing to its pronounced regenerative capacity in many tissues and organs, the zebrafish brain represents an ideal platform to understand the endogenous regeneration mechanisms that restore tissue integrity and function upon injury or disease. Although radial glial and neuronal cell populations have been characterized with respect to specific marker genes, comprehensive transcriptomic profiling of the regenerating telencephalon has not been conducted so far. Here, by processing the lesioned and unlesioned hemispheres of the telencephalon separately, we reveal the differentially expressed genes (DEGs) at the early wound healing and early proliferative stages of regeneration, i.e., 20 h post-lesion (hpl) and 3 days post-lesion (dpl), respectively. At 20 hpl, we detect a far higher number of DEGs in the lesioned hemisphere than in the unlesioned half and only 7% of all DEGs in both halves. However, this difference disappears at 3 dpl, where the lesioned and unlesioned hemispheres share 40% of all DEGs. By performing an extensive comparison of the gene expression profiles in these stages, we unravel that the lesioned hemispheres at 20 hpl and 3 dpl exhibit distinct transcriptional profiles. We further unveil a prominent activation of Wnt/β-catenin signaling at 20 hpl, returning to control level in the lesioned site at 3 dpl. Wnt/β-catenin signaling indeed appears to control a large number of genes associated primarily with the p53, apoptosis, forkhead box O (FoxO), mitogen-activated protein kinase (MAPK), and mammalian target of rapamycin (mTOR) signaling pathways specifically at 20 hpl. Based on these results, we propose that the lesioned and unlesioned hemispheres react to injury dynamically during telencephalon regeneration and that the activation of Wnt/β-catenin signaling at the early wound healing stage plays a key role in the regulation of cellular and molecular events.
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Affiliation(s)
- Yeliz Demirci
- İzmir Biomedicine and Genome Center (IBG), Dokuz Eylül University Health Campus, İzmir, Turkey.,İzmir International Biomedicine and Genome Institute (IBG-İzmir), Dokuz Eylül University, İzmir, Turkey.,European Molecular Biology Laboratory - European Bioinformatics Institute (EMBL-EBI), Cambridge, United Kingdom
| | - Gokhan Cucun
- İzmir Biomedicine and Genome Center (IBG), Dokuz Eylül University Health Campus, İzmir, Turkey.,İzmir International Biomedicine and Genome Institute (IBG-İzmir), Dokuz Eylül University, İzmir, Turkey
| | - Yusuf Kaan Poyraz
- İzmir Biomedicine and Genome Center (IBG), Dokuz Eylül University Health Campus, İzmir, Turkey.,İzmir International Biomedicine and Genome Institute (IBG-İzmir), Dokuz Eylül University, İzmir, Turkey
| | - Suhaib Mohammed
- European Molecular Biology Laboratory - European Bioinformatics Institute (EMBL-EBI), Cambridge, United Kingdom
| | | | - Irene Papatheodorou
- European Molecular Biology Laboratory - European Bioinformatics Institute (EMBL-EBI), Cambridge, United Kingdom
| | - Gunes Ozhan
- İzmir Biomedicine and Genome Center (IBG), Dokuz Eylül University Health Campus, İzmir, Turkey.,İzmir International Biomedicine and Genome Institute (IBG-İzmir), Dokuz Eylül University, İzmir, Turkey
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7
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Girsch W, Bijak M, Heger G, Koller R, Lanmüller H, Mayr W, Thoma H, Losert U. Monitoring of Fes-Induced Muscle Activity by Continuous Emg-Recording. Int J Artif Organs 2018. [DOI: 10.1177/039139889501800608] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Functional Electrical Stimulation (FES) requires information on the stimulated muscle for adjustment of the stimulation current, avoidance of muscle fatigue during the conditioning period and long term follow-up. Several applications of chronical FES are in clinical practice, but a system for direct registration of muscle activity under FES still does not exist. In six sheep the right Latissimus Dorsi Muscle (LDM) and Thoracodorsal Nerve were exposed. Stimulation electrodes were applied to each nerve and 3 EMG-applied sensing electrodes were placed into each LDM. The LDM tendon was connected to a force transducer. Burst stimulation was applied and the amplitude was increased from 0 to 4 mA in steps from burst to burst. EMG (M-wave) was amplified and recorded continuously via modified instrumentation amplifier, oscilloscope and tape recorder. Isometric muscle tension was recorded using force transducer, AID interface and PC. Continuous EMG-recording was performed in all cases. Simultaneous recording of muscle tension and EMG revealed a close correlation (lrl=0.95, p < 0.0001) between muscle strength and amplitude of the M-wave. Continuous recording of the EMG seems to be a reliable method for direct monitoring of the stimulated muscle. Three intramuscular electrodes can provide enough information to monitor FES induced muscle activity.
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Affiliation(s)
- W. Girsch
- Department for Plastic and Reconstructive Surgery, University of Vienna - Austria
| | - M Bijak
- Department of Biomedical Engineering and Physics, University of Vienna - Austria
| | - G. Heger
- Department of Biomedical Engineering and Physics, University of Vienna - Austria
| | - R. Koller
- Department for Plastic and Reconstructive Surgery, University of Vienna - Austria
| | - H. Lanmüller
- Department of Biomedical Engineering and Physics, University of Vienna - Austria
| | - W. Mayr
- Department of Biomedical Engineering and Physics, University of Vienna - Austria
| | - H. Thoma
- Department of Biomedical Engineering and Physics, University of Vienna - Austria
| | - U. Losert
- Department for Biomedical Investigation, University of Vienna - Austria
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8
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Ocherashvili A, Bogucarska T, Beck A, Heger G, Mosconi M, Roesgen E, Crochemore JM, Mayorov V, Varasino G, Pedersen B. Detection of Combined n/γ Fission Signatures Induced by an Epithermal Neutron Source. Journal of Nuclear Engineering and Radiation Science 2017. [DOI: 10.1115/1.4036698] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this paper, a method is presented for the detection of special nuclear materials (SNMs) in shielded containers, which is both sensitive and applicable under field conditions. The method uses an external pulsed neutron source to induce fission in SNM and subsequent detection of the fast prompt fission neutrons. The detectors surrounding the container under investigation are liquid scintillation detectors able to distinguish gamma rays from fast neutrons by means of pulse shape discrimination method (PSD). One advantage of these detectors, besides the ability for PSD analysis, is that the analog signal from a detection event is of very short duration (typically few tens of nanoseconds). This allows the use of very short coincidence gates for the detection of the prompt fission neutrons in multiple detectors, while benefiting from a low background coincidence rate, yielding a low detection limit. Another principle advantage of this method derives from the fact that the external neutron source is pulsed. By proper time gating, the interrogation can be conducted by epithermal source neutrons only. These neutrons do not appear in the fast neutron signal following the PSD analysis, thus providing a fundamental method for separating the interrogating source neutrons from the sample response in the form of fast fission neutrons. This paper describes laboratory tests with a configuration of eight detectors in the Pulsed Neutron Interrogation Test Assembly (PUNITA). Both the photon and neutron signature for induced fission is observed, and the methods used to isolate these signatures are described and demonstrated.
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Affiliation(s)
- A. Ocherashvili
- Physics Department, Nuclear Research Center Negev (NRCN), P.O. Box 9001, Beer-Sheva 84190, Israel
| | - T. Bogucarska
- Nuclear Security Unit, Joint Research Centre, Institute for Transuranium Elements (ITU), European Commission, Via Enrico Fermi 2749, Ispra, VA 21027, Italy
| | - A. Beck
- Physics Department, Nuclear Research Center Negev (NRCN), P.O. Box 9001, Beer-Sheva 84190, Israel
| | - G. Heger
- Israel Atomic Energy Commission (IAEC), P.O. Box 7061, Tel Aviv 61070, Israel
| | - M. Mosconi
- Nuclear Security Unit, Joint Research Centre, Institute for Transuranium Elements (ITU), European Commission, Via Enrico Fermi 2749, Ispra, VA 21027, Italy
| | - E. Roesgen
- Nuclear Security Unit, Joint Research Centre, Institute for Transuranium Elements (ITU), European Commission, Via Enrico Fermi 2749, Ispra, VA 21027, Italy
| | - J.-M. Crochemore
- Nuclear Security Unit, Joint Research Centre, Institute for Transuranium Elements (ITU), European Commission, Via Enrico Fermi 2749, Ispra, VA 21027, Italy
| | - V. Mayorov
- Nuclear Security Unit, Joint Research Centre, Institute for Transuranium Elements (ITU), European Commission, Via Enrico Fermi 2749, Ispra, VA 21027, Italy
| | - G. Varasino
- Nuclear Security Unit, Joint Research Centre, Institute for Transuranium Elements (ITU), European Commission, Via Enrico Fermi 2749, Ispra, VA 21027, Italy
| | - B. Pedersen
- Nuclear Security Unit, Joint Research Centre, Institute for Transuranium Elements (ITU), European Commission, Via Enrico Fermi 2749, Ispra, VA 21027, Italy
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Hutanu V, Luberstetter W, Bourgeat-Lami E, Meven M, Sazonov A, Steffen A, Heger G, Roth G, Lelièvre-Berna E. Implementation of a new Cryopad on the diffractometer POLI at MLZ. Rev Sci Instrum 2016; 87:105108. [PMID: 27802694 DOI: 10.1063/1.4963697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A new polarized neutron single crystal diffractometer POLI (Polarization Investigator) has been developed at the Maier-Leibnitz Zentrum, Garching, Germany. After reviewing existing devices, spherical neutron polarimetry has been implemented on POLI as a main experimental technique using a third-generation cryogenic polarization analysis device (Cryopad) built in cooperation between RWTH University and Institut Laue-Langevin. In this report we describe the realization and present the performance of the new Cryopad on POLI. Some improvements in the construction as well as details regarding calibrations of Cryopad and its practical use are discussed. The reliable operation of the new Cryopad on POLI is also demonstrated.
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Affiliation(s)
- V Hutanu
- Institut für Kristallographie RWTH Aachen University, Jägerstr. 17-19, 52056 Aachen, Germany
| | - W Luberstetter
- Institut für Kristallographie RWTH Aachen University, Jägerstr. 17-19, 52056 Aachen, Germany
| | - E Bourgeat-Lami
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - M Meven
- Institut für Kristallographie RWTH Aachen University, Jägerstr. 17-19, 52056 Aachen, Germany
| | - A Sazonov
- Institut für Kristallographie RWTH Aachen University, Jägerstr. 17-19, 52056 Aachen, Germany
| | - A Steffen
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85747 Garching, Germany
| | - G Heger
- Institut für Kristallographie RWTH Aachen University, Jägerstr. 17-19, 52056 Aachen, Germany
| | - G Roth
- Institut für Kristallographie RWTH Aachen University, Jägerstr. 17-19, 52056 Aachen, Germany
| | - E Lelièvre-Berna
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
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10
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Laligant Y, Pannetier J, Leblanc M, Labbe P, Heger G. Crystal structure refinement of the inverse weberite MnFeF5(H2O)2. Z KRIST-CRYST MATER 2015. [DOI: 10.1524/zkri.1987.181.14.1] [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: 11/24/2022]
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12
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Mereiter Κ, Preisinger Α, Guth Η, Heger G, Hiebl K, Mikenda W. Hydrogen bonds in Schlippe’s salt, Na3SbS4 9H2O and Na3SbS4 - 9 D2O: Diffraction and spectroscopic studies in the temperature range of 75 Κ to 295 Κ. Z KRIST-CRYST MATER 2015. [DOI: 10.1524/zkri.1979.150.14.215] [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: 11/24/2022]
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13
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Babel D, Wall F, Heger G. Strukturen cäsiumhaltiger Fluoride, II1 Die Kristall- und Magnetische Struktur von CsFeF4 / Crystal and Magnetic Structure of CsFeF4. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znb-1974-3-401] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The results of an X-ray structure determination on single crystals of CsFeF4 are reported. The compound crystallizes tetragonally with α = 7.794, c = 6.553 Å, z = 4, in spacegroup P4/nmm-D4h
7 and is a hitherto unknown superstructure variant of the TlAlF4-type. Cesium exhibits 12-coordination (mean value Cs-F = 3.25 Å); the FeF6-octahedra are characteristically shortened normal to the FeF4⁻-layers (Fe-F = 1.962/1.861Å). An improved model is proposed and verified for a related structure of RbFeF4, showing the same features. Neutron diffraction studies on powder samples of CsFeF4 show that both compounds are identical as for their magnetic structures.
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Affiliation(s)
- D. Babel
- Fachbereich Chemie der Universität Marburg
| | - F. Wall
- Fachbereich Chemie der Universität Marburg
| | - G. Heger
- Institut für Kristallographie der Universität Tübingen
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Oh IH, Lee KS, Meven M, Heger G. Single crystal neutron diffraction study on Rb 0.51Tl 0.49H 2PO 4. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311087551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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15
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Knauf WU, Ho AD, Heger G, Hoelzer D, Hunstein W, Thiel E. Detection of Minimal Residual Disease in Adult Acute Lymphoblastic Leukemia by Analysis of Gene Rearrangements and Correlation with Early Relapses. Leuk Lymphoma 2009; 5:57-63. [DOI: 10.3109/10428199109068105] [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: 11/13/2022]
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16
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Knauf WU, Ho AD, Heger G, Doerken B, Moeller P. Mediastinal Clear Cell Lymphoma—A Distinct Entity of B-Cell Derived Lymphoma as Shown by Immunotyping and Analysis of Gene Rearrangements. Leuk Lymphoma 2009; 6:49-52. [DOI: 10.3109/10428199109064878] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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17
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Meven M, Heger G. Unconventional single-crystal diffraction studies with hot neutrons on HEiDi at FRM II. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308094026] [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: 11/10/2022] Open
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18
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Hutanu V, Meven M, Heger G. The new polarised hot-neutron single-crystal diffractometer POLI-HEiDi at FRM II. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308093975] [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: 11/10/2022] Open
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19
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Oh IH, Mattauch S, Heger G, Lee C. Crystal structure analysis of Rb 0.5Tl 0.5H 2PO 4at room temperature by neutron diffraction. Acta Crystallogr A 2008. [DOI: 10.1107/s010876730808416x] [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: 11/10/2022] Open
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20
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Sazonov A, Meven M, Hutanu V, Heger G, Gukasov A, Goujon A. Crystal and magnetic structures of Co 2SiO 4olivine. Acta Crystallogr A 2007. [DOI: 10.1107/s010876730709410x] [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: 11/10/2022] Open
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21
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Oh IH, Merz M, Mattauch S, Heger G. Structural phase transition and hydrogen ordering of TlH2PO4 at low temperature. Acta Crystallogr B Struct Sci 2006; 62:719-28. [PMID: 16983152 DOI: 10.1107/s0108768106018222] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Accepted: 05/16/2006] [Indexed: 11/10/2022]
Abstract
The crystal structure of TlH2PO4 (TDP) has been studied at low temperature. The lattice parameters were derived from high-resolution X-ray powder diffraction in the temperature range between 8 and 300 K. A detailed crystal structure analysis of the antiferroelectric low-temperature phase TDP-III has been performed based on neutron diffraction data measured at 210 K on a twinned crystal consisting of two domain states. The structure model in the triclinic space group P\bar 1 is characterized by a complete ordering of all the H atoms in the asymmetric O—H...O hydrogen bonds. The phase transition from the ferroelastic TDP-II to the antiferroelectric TDP-III phase at 229.5 ± 0.5 K is only slightly of first order and shows no detectable hysteresis effects. Its mechanism is driven by the hydrogen ordering between the partially ordered TDP-II state and the completely ordered TDP-III state. The polymorphism of TDP and the fully deuterated TlD2PO4 (DTDP) is presented in the form of group–subgroup relations between the different space groups.
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Affiliation(s)
- I H Oh
- HANARO Utilization Technology Development Division, HANARO Application Center, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yusung, Daejon, Korea 305-353
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22
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23
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Mattauch S, Heger G, Michel KH. High resolution neutron and X-ray diffraction studies as a function of temperature and electric field of the ferroelectric phase transition of RDP. Cryst Res Technol 2004. [DOI: 10.1002/crat.200410289] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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24
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Meven M, Heger G. HEiDi, new single-crystal diffractometer at the hot source of FRM-II. Acta Crystallogr A 2004. [DOI: 10.1107/s0108767304097788] [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: 11/10/2022] Open
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25
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Scherf C, Ivanov NR, Hahn T, Klapper H, Heger G. Relation between structural phase transitions and transformation twins of KLiSO 4. Acta Crystallogr A 2002. [DOI: 10.1107/s0108767302094990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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26
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Sparta KM, Roth G, Heger G, Masuda T, Uchinokura K. Redetermination of the room temperature structure of BaCuSi 2O 6. Acta Crystallogr A 2002. [DOI: 10.1107/s0108767302098148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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27
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Michel G, Wirion R, Keipes M, Scharpantgen R, Heger G. [Lipiwatch: a study of the treatment of dyslipidemias in Luxembourg]. Bull Soc Sci Med Grand Duche Luxemb 2001:29-36. [PMID: 11570211] [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] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
LIPIWATCH is an observational study which has been initiated for 6 months in Belgium and in Luxembourg in 1997 to evaluate if patients treated by lipid-lowering drugs could reach the recommendations of the EAS and NCEP II for LDL-C. 76 patients (31 men) with a mean age of 59.2 +/- 11.39 years were included. 96% of patients had at least one other associated cardiovascular risk factor. After 6 months of treatment, 33% of all patients and only 30% of patients with coronary heart disease or peripheral vascular disease or at least 2 other risk factors reached the recommendations of the EAS. 25% of all patients and only 20% of patients with known coronary heart disease reached the NCEP II recommendations. 55% of patients had a statin prescribed and 38% a fibrate. Mean total cholesterol and mean LDL-C was lowered by 20% and 19% after 6 months. These disappointing results confirmed an insufficient awareness by physicians and patients, inadequate dosages of drugs and a bad compliance by patients.
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Affiliation(s)
- G Michel
- Service d'endocrinologie-diabétologie, Centre Hospitalier Luxembourg
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28
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Lehner N, Strobel K, Geick R, Heger G. Lattice dynamics in perovskite-type layer structures. FIR studies of (CH3NH3)2MnCl4and (CH3NH3)2FeCl4. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/8/23/023] [Citation(s) in RCA: 38] [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] [Indexed: 11/11/2022]
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29
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30
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31
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Lehner N, Rauh H, Strobel K, Geick R, Heger G, Bouillot J, Renker B, Rousseau M, Stirling WG. Lattice dynamics, lattice instabilities and phase transitions in fluoride perovskites. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/15/32/015] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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32
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33
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Mattauch S, Paulus W, Glinnemann J, Heger G. Structure of the hydrated phase of RbD 2PO 4(DRDP): RbD 2PO 4*D 2O. Acta Crystallogr A 2000. [DOI: 10.1107/s0108767300027860] [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: 11/10/2022] Open
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34
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Scherf C, Rouède D, Le Grand Y, Ivanov NR, Hahn T, Klapper H, Heger G. Opposite Polarity Twin Domains of KLiSO 4. Acta Crystallogr A 2000. [DOI: 10.1107/s010876730002818x] [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: 11/10/2022] Open
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35
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Sparta K, Redhammer G, Roussel P, Roth G, Heger G. Evidence for a structural phase transition in the quasi-2D spin dimer system SrCu 2(BO 3) 2. Acta Crystallogr A 2000. [DOI: 10.1107/s0108767300028233] [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: 11/10/2022] Open
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36
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Klapper H, Scherf C, Hahn T, Heger G, Ivanov NR. Symmetry relations between twin domains and experimental methods of their determination. Acta Crystallogr A 2000. [DOI: 10.1107/s0108767300023564] [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: 11/10/2022] Open
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37
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38
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Abstract
The crystal structure of the antiferroelectric phase of TlD2PO4, deuterated thallium dihydrogenphosphate, has been determined from single-crystal neutron diffraction data collected at room temperature. The para-antiferroelectric transition (T_c^d = 353 K) of TlD2PO4 is analysed from a structural point of view and compared with the phase transition of TlH2PO4 at TI
= 357 K, already characterized. The distinct phase sequences observed in the two compounds when decreasing temperature from that of the high-temperature prototype phase (prototype phase/room-temperature phase/low-temperature phase) are discussed and associated with the different ordering of the two crystallographically inequivalent H (D) atoms existing in the prototype phase.
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39
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Howorka K, Heger G, Schabmann A, Skrabal F, Pumprla J. Weak relationship between symptom perception and objective hypoglycaemia-induced changes of autonomic function in hypoglycaemia unawareness in diabetes. Acta Diabetol 1998; 35:1-8. [PMID: 9625282 DOI: 10.1007/s005920050093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
To assess the relationship between symptom perception and neurophysiological characteristics in hypoglycaemia unawareness, we investigated the awareness of symptoms, objective changes of autonomic function and counter-regulatory neuroendocrine responses to hypoglycaemia in intensively treated type I (insulin-dependent) diabetic patients with different degrees of hypoglycaemia unawareness. Hypoglycaemia (venous plasma glucose below 2.2 mmol/l) was induced with an intravenous insulin bolus in subjects with a history of repeated severe hypoglycaemia and hypoglycaemia unawareness (n = 10) and in a comparable group with good awareness of hypoglycaemia (n = 8). Autonomic symptoms, selected parameters of autonomic function and counter-regulatory hormones were assessed serially. Although hypoglycaemia was more pronounced in unaware patients (1.6 vs 2.0 mmol/l, P = 0.05), their induced adrenaline response was markedly impaired (delta adrenaline: 1.25+/-1.10 vs 2.55+/-1.46 nmol/l, P = 0.05). Astonishingly, differences between both patient groups in the course of autonomic function changes did not reach the level of significance (P = 0.35-0.92), although the unaware group reported markedly fewer autonomic symptoms, both neurogenic (P = 0.001) and neuroglycopenic (P = 0.04) than the aware group. This study indicates that in hypoglycaemia unawareness even extensive changes in autonomic function are not sufficient for the perception of hypoglycaemia and confirms that the central nervous system plays an important role in the awareness of hypoglycaemia.
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Affiliation(s)
- K Howorka
- Department of Biomedical Engineering and Physics, University of Vienna, Allgemeines Krankenhaus, Vienna, Austria
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40
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Abstract
The presence of heart rate variability (HRV) in patients with cardiac denervation after heart transplantation raised our interest in HRV of isolated, denervated hearts. Hearts from seven adult white ELCO rabbits were transferred to a perfusion apparatus. All hearts were perfused in the working mode and in the Langendorff mode for 20 minutes each. HRV was analyzed in the frequency domain. A computer simulated test ECG at a constant rate of 2 Hz was used for error estimation of the system. In the isolated, denervated heart, HRV was of random, broadband fluctuations, different from the well-characterized oscillations at specific frequencies in intact animals. Mean NN was 423 +/- 51 ms in the Langendorff mode, 406 +/- 33 ms in the working heart mode, and 500 ms in the test ECG. Total power was 663 +/- 207 ms2, 817 +/- 318 ms2, and 3.7 ms2, respectively. There was no significant difference in any measure of HRV between Langendorff and working heart modes. The data provide evidence for the presence of HRV in isolated, denervated rabbit hearts. Left atrial and ventricular filling, i.e., the working heart mode, did not alter HRV, indicating that left atrial or ventricular stretch did not influence the sinus nodal discharge rate.
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Affiliation(s)
- B Frey
- Department of Internal Medicine II, University of Vienna, Austria
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41
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Glinnemann J, Becker M, Hahn T, Heger G. Structural relationships in KH 2PO 4-type compounds. Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396081287] [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: 11/10/2022] Open
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42
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Heger G, Rios S, Paulus W, Cousson A, Quilichini M, Becker M, Glinnemann J. Polymorphism of TlH 2PO 4and TlD 2PO 4. Acta Crystallogr A 1996. [DOI: 10.1107/s010876739608230x] [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: 11/10/2022] Open
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43
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Paulus W, Cousson A, Heger G, Revcolevschi A, Dhalenne G, Hosoya S, Kvardakov V. Oxygen defect structure in La 2MO 4+δ( M= Cu, Ni, Co). Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396084206] [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: 11/10/2022] Open
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44
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Klapper H, Hahn T, Scherf C, Park HM, Heger G. Twin domains and phase transitions of KLiSO 4. Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396082244] [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: 11/10/2022] Open
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45
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Bashir J, Nasir Khan M, Waheed A, Butt NM, Heger G. Atomic thermal parameters of TiN by powder elastic neutron diffraction. J Appl Crystallogr 1996. [DOI: 10.1107/s0021889895012490] [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: 11/10/2022] Open
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46
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Braden M, Wilkendorf G, Lorenzana J, Aïn M, McIntyre GJ, Behruzi M, Heger G, Dhalenne G, Revcolevschi A. Structural analysis of CuGeO3: Relation between nuclear structure and magnetic interaction. Phys Rev B Condens Matter 1996; 54:1105-1116. [PMID: 9985380 DOI: 10.1103/physrevb.54.1105] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Howorka K, Heger G, Schabmann A, Anderer P, Tribl G, Zeitlhofer J. Severe hypoglycaemia unawareness is associated with an early decrease in vigilance during hypoglycaemia. Psychoneuroendocrinology 1996; 21:295-312. [PMID: 8817728 DOI: 10.1016/0306-4530(95)00034-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To elucidate neurophysiological characteristics in hypoglycaemia unawareness, we investigated the relationship between electroencephalography (EEG) parameters of vigilance and awareness of various symptom categories early in response to hypoglycaemia in intensively treated diabetic patients with different degrees of hypoglycaemia unawareness. Hypoglycaemia (venous plasma glucose below 2.2 mmol/1) was induced with an intravenous insulin bolus in seven patients with insulin-dependent diabetes mellitus (IDDM) with a history of hypoglycaemia unawareness and repeated severe hypoglycaemia, as well as in a group of seven IDDM patients with good awareness of hypoglycaemia. Both groups were comparable in age, treatment strategy, glycaemic control and level of late complications. Basic cognitive performance and other symptom categories were estimated serially during a period of 2 h following the insulin bolus. A vigilance-controlled EEG was recorded continuously; its automatic analysis included the evaluation of vigilance indices. In the baseline prehypoglycaemic state, hypoglycaemia unaware patients showed higher initial vigilance (p = .05) than the aware group. Unaware patients reported fewer neurogenic (p = .002, mainly cholinergic, p = .009) hypoglycaemia symptoms during hypoglycaemia, and developed an impairment in cognitive performance over time (p = .002). EEG analysis indicated a more rapid decrease in vigilance after the hypoglycaemic stimulus for unaware patients than for aware patients. The lowering of plasma glucose to 3.06-3.89 mmol/l already induced a significant increase in delta and theta, as well as a decrease in alpha relative power only in the unaware group. Differences between groups with regards to the degree of deceleration were most pronounced early, during only slight hypoglycaemia, and topographically spread over central and parietal brain regions. Further lowering of plasma glucose induced an even more pronounced, abrupt increase in slow waves in unaware patients at higher plasma glucose levels than in hypoglycaemia aware subjects (for delta waves at 2.41 +/- 0.16 vs. 1.96 +/- 0.1 mmol/l, p = .04). This preceded the worsening of cognitive performance during hypoglycaemia in unaware patients by 19 +/- 3 min. Hypoglycaemia unawareness associated with previous unconsciousness is associated with- and may be the result of-an early hypoglycaemia-induced reduction in vigilance and an early EEG deceleration, which seems to be a teleologically effective measure for delaying eventual cerebral energy failure in hypoglycaemia.
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Affiliation(s)
- K Howorka
- Department of Biomedical Engineering and Physics, University of Vienna, Austria
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48
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Schiebel P, Wulf K, Prandl W, Heger G, Papoular R, Paulus W. Orientationa Disorder, the Orientational Density Distribution and the Rotational Potential in C60. Acta Crystallogr A 1996. [DOI: 10.1107/s0108767395012566] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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49
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Heger G, Howorka K, Thoma H, Tribl G, Zeitlhofer J. Monitoring set-up for selection of parameters for detection of hypoglycaemia in diabetic patients. Med Biol Eng Comput 1996; 34:69-75. [PMID: 8857314 DOI: 10.1007/bf02637024] [Citation(s) in RCA: 21] [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: 02/02/2023]
Abstract
Recurrent severe hypoglycaemia is often an unsolved problem in diabetic patients under intensified insulin treatment. As no reliable long-term stable blood glucose sensor has yet been developed, registration of other body function changes could help to detect severe hypoglycaemia. A measuring system is described, capable on the one hand of recording EEG, heart rate, peripheral pulse, skin temperature, respiratory movements, skin impedance and arterial blood pressure, and capable of registering plasma glucose, counter-regulatory hormones, symptoms and cognitive performance under experimental conditions during hypoglycaemia, on the other. In a clinical study involving both insulin-induced hypoglycaemia in healthy subjects and insulin-dependent diabetic patients, the practical value and the character of changes of the recorded parameters are investigated. Currently insensitivity to hypoglycaemia, impracticability, complexity or susceptibility to artefacts make use of most parameters unsuitable for hypoglycaemia prevention. It is believed, however, that future efforts could result in indirect registration of hypoglycaemia, including a qualified combination of different parameters, individual adaptation in accordance with particular responses of individual patients, together with new measuring and sensor techniques.
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Affiliation(s)
- G Heger
- Department of Biomedical Engineering and Physics, University of Vienna, Austria
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50
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Tribl G, Howorka K, Heger G, Anderer P, Thoma H, Zeitlhofer J. EEG topography during insulin-induced hypoglycemia in patients with insulin-dependent diabetes mellitus. Eur Neurol 1996; 36:303-9. [PMID: 8864713 DOI: 10.1159/000117277] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [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: 02/02/2023]
Abstract
A group of young patients with insulin-dependent diabetes mellitus (n = 14; 8 men, 6 women; 33.1 +/- 8.9 years) were examined by topographic EEG mapping under normoglycemic and hypoglycemic conditions (glucose levels after intravenous insulin injection down to 32.6 +/- 7.6 mg/dl). From the clinical aspect, 7 of them had a good and 7 had a poor awareness of hypoglycemia. During hypoglycemia, a decrease in alpha activity (p < 0.05), an increase in delta (p < 0.05), and especially in theta activity (p < 0.05) were found. The most sensitive parameter was the alpha/theta ratio. In the range of slight hypoglycemia (50-60 mg/dl) the increase in delta and theta activity showed a topographic maximum in lateral frontal regions. During deep hypoglycemia there was a topographic maximum of slow frequencies in posterior parts of the brain (centrotemporal to parieto-occipital regions). The differences between the group with good and with poor awareness of hypoglycemia were most pronounced during slight hypoglycemia in C3, C4, and Pz (p < 0.05). At lower glucose levels group distinction was no longer possible. These EEG changes correspond to a temporary organic brain syndrome.
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Affiliation(s)
- G Tribl
- Clinic of Neurology, University of Vienna, Austria
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