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Bleeker EAJ, Swart E, Braakhuis H, Fernández Cruz ML, Friedrichs S, Gosens I, Herzberg F, Jensen KA, von der Kammer F, Kettelarij JAB, Navas JM, Rasmussen K, Schwirn K, Visser M. Towards harmonisation of testing of nanomaterials for EU regulatory requirements on chemical safety - A proposal for further actions. Regul Toxicol Pharmacol 2023; 139:105360. [PMID: 36804527 DOI: 10.1016/j.yrtph.2023.105360] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023]
Abstract
Over the recent years, EU chemicals legislation, guidance and test guidelines have been developed or adapted for nanomaterials to facilitate safe use of nanomaterials. This paper provides an overview of the information requirements across different EU regulatory areas. For each information requirement, a group of 22 experts identified potential needs for further action to accommodate guidance and test guidelines to nanomaterials. Eleven different needs for action were identified, capturing twenty-two information requirements that are specific to nanomaterials and relevant to multiple regulatory areas. These were further reduced to three overarching issues: 1) resolve issues around nanomaterial dispersion stability and dosing in toxicity testing, in particular for human health endpoints, 2) further develop tests or guidance on degradation and transformation of organic nanomaterials or nanomaterials with organic components, and 3) further develop tests and guidance to measure (a)cellular reactivity of nanomaterials. Efforts towards addressing these issues will result in better fit-for-purpose test methods for (EU) regulatory compliance. Moreover, it secures validity of hazard and risk assessments of nanomaterials. The results of the study accentuate the need for a structural process of identification of information needs and knowledge generation, preferably as part of risk governance and closely connected to technological innovation policy.
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Affiliation(s)
- Eric A J Bleeker
- National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA, Bilthoven, the Netherlands.
| | - Elmer Swart
- National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA, Bilthoven, the Netherlands
| | - Hedwig Braakhuis
- National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA, Bilthoven, the Netherlands
| | - María Luisa Fernández Cruz
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), CSIC, Ctra. De la Coruña Km 7,5, 28040, Madrid, Spain
| | | | - Ilse Gosens
- National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA, Bilthoven, the Netherlands
| | - Frank Herzberg
- German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Keld Alstrup Jensen
- The National Research Centre for the Working Environment (NRCWE), 105 Lersø Parkallé, DK-2100, Copenhagen, Denmark
| | - Frank von der Kammer
- University of Vienna, Centre for Microbiology and Environmental Systems Science, Department of Environmental Geosciences, Josef-Holaubek-Platz 2, 1090, Vienna, Austria
| | - Jolinde A B Kettelarij
- National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA, Bilthoven, the Netherlands
| | - Jose María Navas
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), CSIC, Ctra. De la Coruña Km 7,5, 28040, Madrid, Spain
| | | | - Kathrin Schwirn
- German Environment Agency (UBA), Woerlitzer Platz 1, 06844, Dessau-Rosslau, Germany
| | - Maaike Visser
- National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA, Bilthoven, the Netherlands
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Noethel M, Schmidt A, Mulder MT, Vanmierlo T, Friedrichs S, Schmidt SV, Voortman G, Goody P, Zimmer S, Nickenig G, Luetjohann D, Jehle J. LXR-beta signalling is a key mediator in the pathogenesis of aortic valve stenosis and its prevention by saringosterol. Eur Heart J 2022. [DOI: 10.1093/eurheartj/ehac544.3075] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Cholesterol metabolism contributes as a risk factor for aortic valve stenosis (AS), but pharmacological approaches remained unsatisfying. The liver-X-receptor (LXR) is a key regulator in cholesterol metabolism, though its clinical use is limited due to unwanted side effects. The seaweed-derived oxysterol saringosterol is an agonist of the LXRβ, promising a more favourable tolerability.
Purpose
This study aimed to better understand the pathophysiology of aortic valve stenosis and to assess the potential of saringosterol as a targeted pharmacotherapy.
Methods
Tissue samples from aortic valves were collected from patients with AS or aortic valve regurgitation (AR). Transcriptomics were performed and gene ontology (GO) analysis was used to determine pathways and genes that are relevant to AS, and then validated using qPCR.
In vivo, mice received a wire-induced aortic valve stenosis and were either fed a diet supplemented with saringosterol or control diet. Haemodynamic characteristics were assessed using echocardiography. Additionally, hepatic concentrations of saringosterol, expression of LXRβ regulated genes as well as aortic valve thickness and composition were assessed.
In vitro, human aortic valve interstitial cells (VIC) were cultured in a procalcifing medium and stimulated with saringosterol to investigate the underlying molecular mechanisms.
Results
Transcriptomic analysis of AS samples revealed the regulation of several GO-terms related to cholesterol- or lipid metabolism. Many of the genes identified were regulated by LXRβ, suggesting its pathophysiological relevance in AS. We validated this assumption by performing qPCR from aortic valves for the most prominent downstream targets of LXRβ, ABCA1 and ABCG1, with both being differentially regulated.
In vivo, treatment with saringosterol for six weeks resulted in a significant accumulation of saringosterol in liver tissue as well as induction of LXRβ-regulated genes. Furthermore, treatment with saringosterol strikingly reduced the development of AS after wire injury as assessed by echocardiographic and histological measurements.
In vitro, the differentiation of VIC into osteoblastic and myofibroblastic phenotypes was abolished by saringosterol, which reduced the expression of the procalcifying mediators RUNX-2 and ACTA-2 in a dose-dependent manner.
Conclusion
We identified LXRβ-signalling as a key regulator in the pathophysiology of AS. Transcriptomic analyses revealed that cholesterol metabolism was altered in human AS, and many of the genes involved were linked to the LXRβ. In a murine model, we demonstrated that oral application of saringosterol induced LXRβ-activity and mitigated the development of AS. In vitro experiments demonstrated that saringosterol prevents adverse cell differentiation of VIC, which provides a mechanistic explanation.
Funding Acknowledgement
Type of funding sources: Public Institution(s). Main funding source(s): BONFOR Universität Bonn
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Affiliation(s)
- M Noethel
- University Hospital Bonn, Department of Internal Medicine II, Cardiology, Pneumology, Angiology , Bonn , Germany
| | - A Schmidt
- University Hospital Bonn, Department of Internal Medicine II, Cardiology, Pneumology, Angiology , Bonn , Germany
| | - M T Mulder
- Erasmus University Medical Centre, Section Pharmacology and Vascular Medicine , Rotterdam , The Netherlands
| | - T Vanmierlo
- Hasselt University, Biomedical Research Institute, European Graduate School of Neuroscience , Hasselt , Belgium
| | - S Friedrichs
- University Hospital Bonn, Institute of Clinical Chemistry and Clinical Pharmacology , Bonn , Germany
| | - S V Schmidt
- Institute of Innate Immunity, University of Bonn , Bonn , Germany
| | - G Voortman
- Erasmus University Medical Centre, Section Pharmacology and Vascular Medicine , Rotterdam , The Netherlands
| | - P Goody
- University Hospital Bonn, Department of Internal Medicine II, Cardiology, Pneumology, Angiology , Bonn , Germany
| | - S Zimmer
- University Hospital Bonn, Department of Internal Medicine II, Cardiology, Pneumology, Angiology , Bonn , Germany
| | - G Nickenig
- University Hospital Bonn, Department of Internal Medicine II, Cardiology, Pneumology, Angiology , Bonn , Germany
| | - D Luetjohann
- University Hospital Bonn, Institute of Clinical Chemistry and Clinical Pharmacology , Bonn , Germany
| | - J Jehle
- University Hospital Bonn, Department of Internal Medicine II, Cardiology, Pneumology, Angiology , Bonn , Germany
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Friedrichs S, Ludlow K, Kearns P. Regulatory and Policy Considerations Around Genome Editing in Agriculture. Methods Mol Biol 2022; 2495:327-366. [PMID: 35696041 DOI: 10.1007/978-1-0716-2301-5_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The increasingly widespread use of genome editing brought with it a fierce debate about the most adequate regulation of this latest innovation in modern biotechnology and the products resulting from it. In almost all cases, this debate has become a repetition or continuation of the deliberations concerning genetically modified organisms (GMOs) of the 1990s and early 2000s.This chapter aims to untangle the historically influenced and often biased arguments of the debates by addressing the complex question of the correct interpretation of relevant underlying law and its applicability. In doing so, the chapter considers 25 countries and regions that have published results or ongoing investigations and discussions pertaining to the governance of genome editing in their jurisdictions: 16 have published policies or signed statements that exempt gene edited plants from GMO-regulations, as long as no foreign DNA or transgene remained in the final product. Such exemptions are based on the widely supported acceptance that the products of the underlying genome editing processes resemble those of "conventional breeding" techniques. These policies and statements often refer to the important role that modern precision biotechnologies, of which genome editing is one, play in addressing some of the world's overarching challenges, such as the loss of biodiversity, pest and disease control, and climate change; they are furthermore shown to exhibit an adherence to the four universal principles of good regulation: (a) proportionality, (b) non-discrimination, (c) predictability, and (d) enforceability. And while it is the right of jurisdictions to develop their own regulations independent from that of their neighbors, it is specifically the principle of "enforceability" that may become the ultimate litmus test of those regulations that do not grant exemptions from GMO-regulations.
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Affiliation(s)
| | - Karinne Ludlow
- Faculty of Law, Monash University, Clayton, VIC, Australia
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Affiliation(s)
| | - Diana M Bowman
- Sandra Day O'Connor College of Law, Arizona State University, Phoenix, AZ, USA
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Beal J, Goñi-Moreno A, Myers C, Hecht A, de Vicente MDC, Parco M, Schmidt M, Timmis K, Baldwin G, Friedrichs S, Freemont P, Kiga D, Ordozgoiti E, Rennig M, Rios L, Tanner K, de Lorenzo V, Porcar M. The long journey towards standards for engineering biosystems: Are the Molecular Biology and the Biotech communities ready to standardise? EMBO Rep 2020; 21:e50521. [PMID: 32337821 PMCID: PMC7202200 DOI: 10.15252/embr.202050521] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jacob Beal
- Raytheon BBN Technologies, Cambridge, MA, USA
| | - Angel Goñi-Moreno
- School of Computing, Newcastle University, Newcastle upon Tyne, UK.,Centro de Biotecnología y Genómica de Plantas, (CBGP, UPM-INIA), Universidad Politécnica de Madrid, Pozuelo de Alarcón, Spain
| | | | | | | | | | | | - Kenneth Timmis
- Institute of Microbiology, Technical University Braunschweig, Braunschweig, Germany
| | | | | | | | | | | | - Maja Rennig
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark
| | - Leonardo Rios
- Institute for Bioengineering and Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
| | | | | | - Manuel Porcar
- Institute for Integrative Systems Biology, University of Valencia, Paterna, Spain
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Otto S, Luetjohann D, Kerksiek A, Friedrichs S, Schulze PC, Poerner TC, Weingaertner O. P5625Markers for cholesterol absorption are associated with In-stent-restenosis after coronary stenting in stable coronary artery disease: An Optical Coherence Tomography study. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz746.0569] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Background
Plant sterols are suspected to exert atherosclerotic propensity. Modern drug-eluting stents are superior to bare metal stents but show a late catch up phenomenon for restenosis. Due to its superb resolution, optical coherence tomography (OCT) has the capability to identify and quantifiy very early patterns of in-stent proliferation. Studies have shown that in-stent neointimal proliferation is linked to late in-stent stenosis.
Purpose
This study aimed to analyze associations of plasma levels for markers of cholesterol homeostasis such as campesterol and sitosterol (markers for cholesterol absorption) as well as lanosterol (marker for cholesterol synthesis)and and their respective oxides with In-stent restenosis after stent deployment in stable coronary artery disease.
Methods
Plasma cholesterol was measured by gas chromatography-flame ionization detection. Plasma campesterol, sitosterol and lanosterol and their oxides were analyzed by gas chromatography-mass selective detection. In-stent proliferation (restenosis) was assessed after six months by OCT in 33 patients (21 males). A quantitative OCT algorithm was applied to each stent by steps of one mm and in-stent proliferation volumes and areas were calculated and normalized to stent length and area. In-stent proliferation can be measured by OCT as global volumes and focal areas.
Results
No clinically significant restenosis or angiographic restenosis of >30% was observed at 6-month f/u. Mean cholesterol level was 166,5±62,8 mg/dl and positively correlated with proliferation volume/cm (r=0.316, p=0.037) and absolute median proliferation area (r=0.322, p=0.029). Absolute median proliferation area and relative median proliferation area correlated positively with markers for cholesterol absorption such as campesterol-to-cholesterol (r=0.277, p=0.07 and 0.315, p=0.037) and sitosterol-to-cholesterol (r=0.237, p=0.092 and 0.322, p=0.034), whereas lanosterol (a marker for cholesterol synthesis) and its ratio to cholesterol correlated negatively with proliferation volumes and areas (p<0.05; table). Moreover, 7-beta-OH-campesterol correlated positively with proliferation volumes and areas (p<0.05, table). Also, the ratio of 7-beta-OH-campesterol-to-cholesterol correlated positively with proliferation volumes and areas (p<0.1,; table), but did not reach significance in this relatively small sample size. Morevover, there was a positive association of the sum of all plant sterol oxides with In-stent restenosis (data not shown).
Conclusions
In this hypothesis-generating study, in-stent proliferation assessed by OCT at six months follow-up was positively associated with markers for cholesterol absorption and negatively associated with markers for cholesterol synthesis. Larger studies will have to evaluate whether patients with high cholesterol absorption might benefit in particular from combined-lipid-lowering therapy with a statin and a cholesterol absorption Inhibitor.
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Affiliation(s)
- S Otto
- University Hospital Jena, Jena, Germany
| | - D Luetjohann
- University Hospital Bonn, Dept. of Clinical Pharmacology and Clinical Chemistry, Bonn, Germany
| | - A Kerksiek
- University Hospital Bonn, Dept. of Clinical Pharmacology and Clinical Chemistry, Bonn, Germany
| | - S Friedrichs
- University Hospital Bonn, Dept. of Clinical Pharmacology and Clinical Chemistry, Bonn, Germany
| | - P C Schulze
- Clinic of Internal Medicine I, Cardiology Department, Jena, Germany
| | - T C Poerner
- Marienhospital, Dept. of Internal Medicine and Cardiology, Aachen, Germany
| | - O Weingaertner
- Clinic of Internal Medicine I, Cardiology Department, Jena, Germany
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Friedrichs S, Takasu Y, Kearns P, Dagallier B, Oshima R, Schofield J, Moreddu C. Policy Considerations Regarding Genome Editing. Trends Biotechnol 2019; 37:1029-1032. [DOI: 10.1016/j.tibtech.2019.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/10/2019] [Accepted: 05/13/2019] [Indexed: 11/25/2022]
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Friedrichs S, Takasu Y, Kearns P, Dagallier B, Oshima R, Schofield J, Moreddu C. Meeting report of the OECD conference on "Genome Editing: Applications in Agriculture-Implications for Health, Environment and Regulation". Transgenic Res 2019; 28:419-463. [PMID: 31309374 PMCID: PMC6647521 DOI: 10.1007/s11248-019-00154-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The "OECD Conference on Genome Editing: Applications in Agriculture-Implications for Health, Environment and Regulation" was held on the 28-29 June 2018 at the OECD headquarter and conference centre in Paris, France. It brought together policy makers, academia, innovators and other stakeholders involved in the topic, in order to take stock of the current technical developments and implementations of genome editing, as well as their applications in various areas of agriculture and the implications they give rise to (More information on the "OECD Conference on Genome Editing: Applications in Agriculture-Implications for Health, Environment and Regulation" can be found on the OECD Genome Editing hub: http://www.oecd.org/environment/genome-editing-agriculture/ ; the hub also contains the detailed conference programme, the biographies of all conference speakers, the detailed conference abstracts, and the presentations of the two-day conference). The conference aimed to provide a clearer understanding of the regulatory considerations raised by products of genome editing, pointing towards a coherent policy approach to facilitate innovations involving genome editing.
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Affiliation(s)
| | - Yoko Takasu
- Organisation for Economic Co-operation and Development (OECD), 2, Rue André Pascal, 75775, Paris Cedex 16, France
| | - Peter Kearns
- Organisation for Economic Co-operation and Development (OECD), 2, Rue André Pascal, 75775, Paris Cedex 16, France
| | - Bertrand Dagallier
- Organisation for Economic Co-operation and Development (OECD), 2, Rue André Pascal, 75775, Paris Cedex 16, France
| | - Ryudai Oshima
- Organisation for Economic Co-operation and Development (OECD), 2, Rue André Pascal, 75775, Paris Cedex 16, France
| | - Janet Schofield
- Organisation for Economic Co-operation and Development (OECD), 2, Rue André Pascal, 75775, Paris Cedex 16, France
| | - Catherine Moreddu
- Organisation for Economic Co-operation and Development (OECD), 2, Rue André Pascal, 75775, Paris Cedex 16, France
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Weingaertner O, Luetjohann D, Meyer S, Seiler-Mussler S, Fuhrmann A, Schoett HF, Kerksiek A, Friedrichs S, Zawada A, Laufs U, Scheller B, Fliser D, Boehm M, Sijbrands E, Heine GH. P6434Low serum lathosterol levels predict fatal cardiovascular disease and all cause mortality: a prospective cohort study in patients admitted for coronary angiography. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy566.p6434] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- O Weingaertner
- Universitätsklinikum Jena, Klinik für Innere Medizin 1, Jena, Germany
| | - D Luetjohann
- Universitätsklinikum Bonn, Institut für Klinische Pharmakologie und Klinische Chemie, Bonn, Germany
| | - S Meyer
- Klinikum Oldenburg, Abteilung für Kardiologie, Oldenburg, Germany
| | - S Seiler-Mussler
- Universitätsklinikum des Saarlandes, Abteilung für Nieren- und Hochdruckkrankheiten, Homburg/Saar, Germany
| | - A Fuhrmann
- Universitätsklinikum Bonn, Institut für Klinische Pharmakologie und Klinische Chemie, Bonn, Germany
| | - H F Schoett
- Universitätsklinikum Bonn, Institut für Klinische Pharmakologie und Klinische Chemie, Bonn, Germany
| | - A Kerksiek
- Universitätsklinikum Bonn, Institut für Klinische Pharmakologie und Klinische Chemie, Bonn, Germany
| | - S Friedrichs
- Universitätsklinikum Bonn, Institut für Klinische Pharmakologie und Klinische Chemie, Bonn, Germany
| | - A Zawada
- Universitätsklinikum des Saarlandes, Abteilung für Nieren- und Hochdruckkrankheiten, Homburg/Saar, Germany
| | - U Laufs
- Universitätsklinikum Leipzig, Klinik und Poliklinik für Kardiologie, Leipzig, Germany
| | - B Scheller
- Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, Homurg, Germany
| | - D Fliser
- Universitätsklinikum des Saarlandes, Abteilung für Nieren- und Hochdruckkrankheiten, Homburg/Saar, Germany
| | - M Boehm
- Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, Homurg, Germany
| | - E Sijbrands
- Erasmus University Rotterdam, Department of Internal Medicine, Rotterdam, Netherlands
| | - G H Heine
- Universitätsklinikum des Saarlandes, Abteilung für Nieren- und Hochdruckkrankheiten, Homburg/Saar, Germany
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Friedrichs S, Jones PG. Secondary Interactions in Gold(I) Complexes with Thione Ligands, 4. Three Further Salts of the Bis(imidazolidine-2-thione)gold(I) Cation [1, 2]. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znb-2006-1112] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [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
Three structures of the form bis(imidazolidine-2-thione)gold(I) disulfonylamide [disulfonylamide = benzene-1,2-di(sulfonyl)amide (1), di(4-chlorobenzenesulfonyl)amide (2), di(4-iodobenzenesulfonyl) amide (3)] were determined. Compound 3 crystallizes with four independent formula units. The cations in 1 and 3 show an antiperiplanar conformation about the S···S axis, whereas the corresponding torsion angle in 2 is 72°. The packing in 1 consists of linked ribbons in which the NH groups of neighbouring cations are bridged by O-S-O groups of the anions. Compound 2 exhibits a complex layer structure in which several multi-centre hydrogen bonds are observed. The structural subunits of compound 3 involve an alternating anion-cation chain for two of the cations and inversionsymmetric anion-cation dimers for the other two cations. Short C-H···Au contacts (shortest H···Au 2.63 Å in 2) contribute to the packing of compounds 2 and 3.
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Affiliation(s)
- Steffi Friedrichs
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Postfach 3329, D-38023 Braunschweig, Germany
| | - Peter G. Jones
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Postfach 3329, D-38023 Braunschweig, Germany
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Friedrichs S, Jones PG. Secondary Interactions in Gold(I) Complexes with Thione Ligands. 2. Three Ionic Camphorsulfonates with Z’ = 2 [1]. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/znb-2004-0708] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
All three structures of the form bis(thione)gold(I) camphor-10-sulfonate [thione = imidazolidine-2-thione, 1; 1-methyl-imidazolidine-2-thione, 2; thiazolidine-2-thione, 3] crystallize in chiral space groups with Z′ = 2; local inversion symmetry of the cationic assemblies (less pronounced for 3) provides some rationalisation for this. The basic structural units are accounted for in terms of classical hydrogen bonds, leading to rings involving ion pairs for 1 and 2, but to infinite chains of anions and cations for 3. Neighbouring ion pairs in 1 are joined by further classical hydrogen bonds, in 2 via interactions between parallel S-Au-S axes. Other interactions include Au···N for 1, Au···S and Au···O for 3, and weak hydrogen bonds C-H···O and C-H···S, especially between adjacent chains in 3. Each structure is divided into hydrophobic and hydrophilic regions.
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Affiliation(s)
- Steffi Friedrichs
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Postfach 3329, D-38023 Braunschweig, Germany
- Nanoscience Centre, University of Cambridge, 11 J. J. Thomson Avenue, Cambridge CB3 0FF, UK
| | - Peter G. Jones
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Postfach 3329, D-38023 Braunschweig, Germany
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Fittschen M, Reinhard I, Wellek S, Friedrichs S, Bahlmann F. Advanced dynamic Doppler flow of the pulmonary artery in a normal population: reference values from 18 to 41 weeks of gestation calculated by automatic Doppler waveform analysis. Arch Gynecol Obstet 2013; 289:973-80. [DOI: 10.1007/s00404-013-3071-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 10/24/2013] [Indexed: 11/28/2022]
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Vanmierlo T, Popp J, Kölsch H, Friedrichs S, Jessen F, Stoffel-Wagner B, Bertsch T, Hartmann T, Maier W, von Bergmann K, Steinbusch H, Mulder M, Lütjohann D. The plant sterol brassicasterol as additional CSF biomarker in Alzheimer's disease. Acta Psychiatr Scand 2011; 124:184-92. [PMID: 21585343 DOI: 10.1111/j.1600-0447.2011.01713.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Plant sterols (sitosterol, campesterol, stigmasterol and brassicasterol) are solely dietary-derivable sterols that are structurally very similar to cholesterol. In contrast to peripheral cholesterol, plant sterols can cross the blood-brain barrier and accumulate within mammalian brain. As an impaired function of the cerebrospinal fluid (CSF)-blood barrier is linked to neurodegenerative disorders, i.e. Alzheimer's disease (AD), we investigated whether this results in altered plant sterol concentrations in CSF. METHOD Applying gas chromatography/mass spectrometry analysis, plant sterol concentrations were measured in plasma and CSF of patients with AD (n = 67) and controls (n = 29). Age, gender, plasma-to-CSF albumin ratio, CSF Aβ(42) , CSF pTau, APOE4 genotype, and serum creatinine were applied as covariates in the statistical analysis for individual plant sterols in order to compare plasma and CSF plant sterol concentrations between patients with AD and controls. RESULTS Albumin quotient was a consistent predictor in CSF for cholesterol and methyl plant sterols campesterol and brassicasterol. Comparison of lipid parameters per diagnosis based on relevant predictors revealed significantly lower concentrations of brassicasterol (P < 0.001) in CSF of patients with AD. Binary logistic regression analysis revealed that brassicasterol improved the predictive value when added to pTau and Aβ42 in a biomarker model. CONCLUSION Brassicasterol might be a relevant additional biomarker in AD.
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Affiliation(s)
- T Vanmierlo
- Institute of Clinical Chemistry and Clinical Pharmacology, University Clinics Bonn, Germany
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Sloan J, Brown G, Bailey S, Coleman K, Flahaut E, Friedrichs S, Xu C, Green M, Dunin-Borkowski R, Hutchison J, Kirkland A, Meyer R. The Crystallography of Metal Halides formed within Single Walled Carbon Nanotubes. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-633-a14.31] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractThe crystal growth behaviour and crystallography of a variety of metal halides incorporated within single walled carbon nanotubes (SWNTs) as determined by high resolution electron microscopy (HRTEM) is described. Simple packed structures, such as the alkali halides, form related structures within SWNTs that are found to be integral atomic layers in terms of their thickness as a function of the encapsulating SWNT diameter. An enhanced HRTEM image restoration technique reveals precise data concerning lattice distortions present in these crystals. More complex structures, such as those derived from 3D complex, layered and chain halides form related crystal structures within SWNTs. In narrow SWNTs (i.e. with diameters less than ca. 1.6 nm), structures consisting of individual 1D polyhedral chains (1D-PHCs) were obtained that were derived from the corresponding bulk halides structures. In the case of infinite 3D network and layered halides, the 1D polyhedral chains form with lower co-ordinations than in the bulk. Molecular halides also intercalate into SWNTs but these do not readily form organised structures within SWNTs.
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Eckardt A, Kokemüller H, Friedrichs S, Gellrich NC. Rekonstruktion von Kontinuitätsdefekten des Unterkiefers – Klinische Ergebnisse des Zeitraums 1980 bis 2006. Zentralbl Chir 2009. [DOI: 10.1055/s-0029-1238116] [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: 10/20/2022]
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Jones PG, Friedrichs S. Secondary interactions in gold(I) complexes with thione ligands. 5. Two ionic compounds of the form bis(thione)gold(I) bis(4-halobenzenesulfonyl)amide. Acta Crystallogr C 2006; 62:m623-7. [PMID: 17148904 DOI: 10.1107/s0108270106044143] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Accepted: 10/23/2006] [Indexed: 11/10/2022] Open
Abstract
Bis(1,3-thiazolidine-2-thione-kappaS2)gold(I) bis(4-chlorobenzenesulfonyl)amide, [Au(C3H5NS2)2](C12H8Cl2NS2O4), has no imposed symmetry. Classical N-H...N and N-H...O hydrogen bonds link the residues to form chains parallel to the b axis. Weaker interactions involve C-H...O, C-H...Au and a number of X...Cl contacts (X = Cl, S or Au) clustered in the region y approximately equal to 1/4}. In bis(1-methylimidazolidine-2-thione-kappaS2)gold(I) bis(4-iodobenzenesulfonyl)amide, [Au(C4H8N2S)2](C12H8I2NS2O4), the Au atom of the cation and the N atom of the anion lie on the twofold axis (0, y, 1/4}) in the space group C2/c. The formula unit forms a self-contained ring with two symmetry-equivalent N-H...O hydrogen bonds, and weak C-H...X (X = O, I or S), Au...I and I...I contacts are observed. In both compounds, the anions display extended conformations.
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Affiliation(s)
- Peter G Jones
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Postfach 3329, 38023 Braunschweig, Germany.
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Wilson M, Friedrichs S. The formation of low-dimensional metal trihalide crystals in carbon nanotubes. Acta Crystallogr A 2006; 62:287-95. [PMID: 16788268 DOI: 10.1107/s0108767306018101] [Citation(s) in RCA: 13] [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] [Received: 01/06/2006] [Accepted: 05/30/2006] [Indexed: 11/10/2022] Open
Abstract
Molecular dynamics computer simulation models are employed to study the direct filling of single-walled carbon nanotubes (which vary in diameter) with an archetypal metal trihalide, LaCl3. The use of relatively simple potential models allows the investigation of details of both the atomistic filling mechanism and the thermodynamic factors controlling the formation. The resulting low-dimensional crystallites are analysed with respect to bulk crystal structures and compared to experimental high-resolution transmission-electron-microscopy images by simulation of equivalent micrographs from one of the obtained potential models, resulting in excellent agreement between the simulated and experimental images.
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Affiliation(s)
- Mark Wilson
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, England.
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Ducati C, Koziol K, Friedrichs S, Yates TJV, Shaffer MS, Midgley PA, Windle AH. Crystallographic order in multi-walled carbon nanotubes synthesized in the presence of nitrogen. Small 2006; 2:774-84. [PMID: 17193122 DOI: 10.1002/smll.200500513] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Multi-walled carbon nanotubes were synthesized by chemical vapor deposition from pure toluene and toluene/diazine mixtures using ferrocene as a catalyst precursor at 760 degrees C. As recently announced, characterization of the resulting nanotube films showed that, unlike pure carbon nanotubes, those grown in the presence of nitrogen have an extremely high degree of internal order, both in terms of the uniform chirality in the nanotube walls and of the crystallographic register between them. Here, the structure, defects, and morphology of the nanotubes were analyzed in depth using advanced electron microscopy techniques, and compared with existing models and observations. Nitrogen, which seems to be responsible for the dramatic structural order, was found to segregate preferentially within the core of the nanotubes.
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Affiliation(s)
- Caterina Ducati
- Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, UK.
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Abboud S, Viiri L, Luetjohann D, Blecic S, Friedrichs S, Karhunen P, Lehtimäki T, Pandolfo M, Laaksonen R. Mo-W4:4 ApoE gene promoter polymorphisms as determinant of middle age ischemic stroke. ATHEROSCLEROSIS SUPP 2006. [DOI: 10.1016/s1567-5688(06)80047-4] [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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Friedrichs S, Kirkland AI, Meyer RR, Sloan J, Green MLH. LaI2@(18,3)SWNT: the unprecedented structure of a LaI2 "Crystal," encapsulated within a single-walled carbon nanotube. Microsc Microanal 2005; 11:421-30. [PMID: 17481323 DOI: 10.1017/s1431927605050324] [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: 01/05/2004] [Accepted: 05/15/2004] [Indexed: 05/06/2023]
Abstract
The novel crystallization properties of nano-materials represent a great challenge to researchers across all disciplines of materials science. Simple binary solids can be found to adopt unprecedented structures, when confined into nanometer-sized cavities, such as the inner cylindrical bore of single-walled carbon nanotubes (SWNT). Lanthanum iodide was encapsulated within SWNTs and the resulting encapsulation composite was analyzed using energy-dispersive X-ray microanalysis (EDX) and high-resolution transmission electron microscopy (HRTEM) imaging techniques, to reveal a one-dimensional crystal fragment, with the stoichiometry of LaI2, crystallizing in the structure of LaI3 with one third of the iodine positions unoccupied. A complete characterization of the encapsulation composite was achieved using an enhanced image restoration technique, which restores the object wave from a focal series of HRTEM images, providing information about the precise structural data of both filling material and host SWNT, and thereby enabling the identification of the SWNT chirality.
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Affiliation(s)
- Steffi Friedrichs
- Nanoscience Centre, University of Cambridge, 11 J.J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom.
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Friedrichs S, Green MLH. 1-dimensional lanthanide halide crystals encapsulated within single-walled carbon nanotubes –a brief review. ACTA ACUST UNITED AC 2005. [DOI: 10.3139/146.018136] [Citation(s) in RCA: 6] [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: 11/20/2022]
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Abstract
Simple binary solids can be found to adopt unprecedented structures when confined into nanometre-sized cavities, such as the inner cylindrical bore of single-walled carbon nanotubes (SWNT). In the case of the discussed Lal(x)@SWNT encapsulation composite, the Lal2 "crystal" fragment adopts the structure of bulk Lal3, with one third of the iodine positions unoccupied. A complete characterisation of the encapsulation composite was achieved using an enhanced digital restoration approach of high-resolution transmission electron microscopy (HRTEM) images. The resulting complex exit surface wave provides information about the precise structural data of both filling material and host SWNT, establishing the SWNT's chirality and thus enabling a prediction of the composite's overall electron-transport properties.
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Affiliation(s)
- Steffi Friedrichs
- Nanoscience, University of Cambridge, 11 J. J. Thomson Avenue, Cambridge, CB3 OFF, UK.
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Philp E, Sloan J, Kirkland AI, Meyer RR, Friedrichs S, Hutchison JL, Green MLH. An encapsulated helical one-dimensional cobalt iodide nanostructure. Nat Mater 2003; 2:788-91. [PMID: 14634642 DOI: 10.1038/nmat1020] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2003] [Accepted: 09/29/2003] [Indexed: 05/06/2023]
Abstract
Single-walled carbon nanotubes (SWNTs) can be used as templates for the growth of low-dimensional inorganic materials whose structures and properties often differ greatly from those of the bulk. Here we describe the detailed crystallography of an entire helical one-dimensional cobalt diiodide nanostructure encapsulated within a SWNT. This material has an unprecedented twisted double tetrahedral chain structure arising from a rotation of Co(2)I(4) units along its length. The complete nanostructure comprises two distinct regions with oppositely handed helices separated by a short disordered region. The encapsulating SWNT shows a commensurate ovoid distortion reflecting an unexpectedly strong interaction between the nanostructure and the SWNT.
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Affiliation(s)
- Eilidh Philp
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
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Meyer RR, Friedrichs S, Kirkland AI, Sloan J, Hutchison JL, Green MLH. A composite method for the determination of the chirality of single walled carbon nanotubes. J Microsc 2003; 212:152-7. [PMID: 14629564 DOI: 10.1046/j.1365-2818.2003.01240.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [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: 11/20/2022]
Abstract
An approach to the unambiguous determination of the conformation of individual single walled nanotubes utilizing high-resolution transmission electron microscopy and digital image processing is described. The exit plane wave of single walled nanotubes restored from a focal series of images is used in a stepwise characterization procedure utilizing both the phase of the real space restoration and its Fourier transform. A combination of these complementary characterization steps yields an accurate measurement of the chiral vector for an individual nanotube.
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Affiliation(s)
- R R Meyer
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK
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Sloan J, Grosvenor SJ, Friedrichs S, Kirkland AI, Hutchison JL, Green MLH. A One-Dimensional BaI2 Chain with Five- and Six-Coordination, Formed within a Single-Walled Carbon Nanotube. Angew Chem Int Ed Engl 2002. [DOI: 10.1002/1521-3757(20020402)114:7<1204::aid-ange1204>3.0.co;2-j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sloan J, Grosvenor SJ, Friedrichs S, Kirkland AI, Hutchison JL, Green MLH. A one-dimensional BaI2 chain with five- and six-coordination, formed within a single-walled carbon nanotube. Angew Chem Int Ed Engl 2002; 41:1156-9. [PMID: 12491245 DOI: 10.1002/1521-3773(20020402)41:7<1156::aid-anie1156>3.0.co;2-n] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jeremy Sloan
- Inorganic Chemistry Laboratory, University of Oxford, UK.
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Sloan J, Terrones M, Nufer S, Friedrichs S, Bailey SR, Woo HG, Rühle M, Hutchison JL, Green MLH. Metastable one-dimensional AgCl(1)-(x)I(x) solid-solution wurzite "tunnel" crystals formed within single-walled carbon nanotubes. J Am Chem Soc 2002; 124:2116-7. [PMID: 11878956 DOI: 10.1021/ja0173270] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High-resolution transmission electron microscopy and spatially resolved electron loss spectroscopy have revealed that a eutectic mixture of AgCl and AgI crystallizes within single walled carbon nanotubes (SWNTs) as metastable AgCl(1-)(x)I(x) 1D solid solution crystals. The incorporated halide crystals form wurzite "tunnel" structures with locally varying Cl:I ratios and reduced Ag coordination.
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Affiliation(s)
- Jeremy Sloan
- Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, United Kingdom
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Moers O, Friedrichs S, Blaschette A, Jones PG. Lamellare Schichten auf der Grundlage von Wasserstoffbrücken und π-Stapelung: Kristallstrukturen der Komplexe [Mg(H2O)6]Z2 und [Be(H2O)4]Z2?2 H2O mit Z- = C6H4(SO2)2N-: Metallsalze des Benzol-1, 2-di(sulfonyl)amins. 8 [1, 2]. Z Anorg Allg Chem 2002. [DOI: 10.1002/1521-3749(200203)628:3<589::aid-zaac589>3.0.co;2-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [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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Moers O, Friedrichs S, Blaschette A, Jones PG. Zweidimensionale Polymere mit hydrophober Umhüllung: Kristallstrukturen der isostrukturellen Metallkomplexe [M{C6H4(SO2)2N}(H2O)] (M = K, Rb) und des strukturverwandten Ammoniumsalzes [(NH4){C6H4(SO2)2N}(H2O)]. Z Anorg Allg Chem 2001. [DOI: 10.1002/1521-3749(200111)627:11<2528::aid-zaac2528>3.0.co;2-c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Friedrichs S, Sloan J, Green MLH, Meyer RR, Kirkland AI, Hutchison JL. Complete characterisation of a Sb2O3/(21,−8)SWNT inclusion composite. Chem Commun (Camb) 2001. [DOI: 10.1039/b102348a] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Brown G, Bailey SR, Sloan J, Xu C, Friedrichs S, Flahaut E, Coleman KS, Green MLH, Hutchison JL, Dunin-Borkowski RE. Electron beam induced in situ clusterisation of 1D ZrCl4 chains within single-walled carbon nanotubes. Chem Commun (Camb) 2001. [DOI: 10.1039/b101261o] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Xu C, Sloan J, Brown G, Bailey S, Williams VC, Friedrichs S, Coleman KS, Flahaut E, Green MLH, Hutchison JL, Dunin-Borkowski RE. 1D lanthanide halide crystals inserted into single-walled carbon nanotubes. Chem Commun (Camb) 2000. [DOI: 10.1039/b006817i] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Corcoran C, Fawcett J, Friedrichs S, Holloway JH, Hope EG, Russell DR, Saunders GC, Stuart AM. Structural and electronic impact of fluorine in the ortho positions of triphenylphosphine and 1,2-bis(diphenylphosphino)ethane; a comparison of 2,6-difluorophenyl- with pentafluorophenyl-phosphines. ACTA ACUST UNITED AC 2000. [DOI: 10.1039/a907759f] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fawcett J, Friedrichs S, Holloway JH, Hope EG, McKee V, Nieuwenhuyzen M, Russell DR, Saunders GC. Carbon–fluorine bond activation in the reactions between 1,2-bis[bis(2,6-difluorophenyl)phosphino]ethane and [{MCl(μ-Cl)(η5-C5Me5)}2] (M = Rh or Ir). ACTA ACUST UNITED AC 1998. [DOI: 10.1039/a800515j] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hajak G, Rodenbeck A, Bandelow B, Friedrichs S, Huether G, Rüther E. Nocturnal plasma melatonin levels after flunitrazepam administration in healthy subjects. Eur Neuropsychopharmacol 1996; 6:149-53. [PMID: 8791041 DOI: 10.1016/0924-977x(96)00005-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [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: 02/02/2023]
Abstract
Polysomnographic sleep patterns and melatonin secretion were investigated in 5 young (age 25.6 +/- 1.1 years) and 5 middle-aged (age 49.4 +/- 5.4 years) healthy male subjects after intravenous administration of 1 mg flunitrazepam and placebo in a randomized, double-blind and cross-over setting. The area under the curve (AUC) of total nocturnal melatonin plasma concentration decreased 23.3 +/- 11.5% in young subjects (P < or = 0.05) and 39.3 +/- 5.2% in middle-aged subjects (P < or = 0.05) after flunitrazepam infusion compared with placebo infusion. Differences in nocturnal peak values of melatonin were 5.4 +/- 22.0% in young subjects (not significant) and 34.0 +/- 14.7% in middle-aged subjects (p < or = 0.05). Flunitrazepam significantly (P < or = 0.05) improved sleep latency and the number of sleep stage changes in the group of all subjects. These results show that, although the benzodiazepine flunitrazepam improves sleep, it reduces the nocturnal secretion of melatonin, and therefore alters the circadian rhythm of a hormone which is supposed to play a special role in circadian sleep-wake rhythmicity.
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Affiliation(s)
- G Hajak
- Department of Psychiatry, University of Göttingen, Germany
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Hütten A, Bernardi J, Friedrichs S, Thomas G, Balcells L. Microstructural influence on magnetic properties and giant magnetoresistance of melt-spun gold-cobalt. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/0956-716x(95)00401-g] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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