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Shen J, Terskikh V, Struppe J, Hassan A, Monette M, Hung I, Gan Z, Brinkmann A, Wu G. Solid-state 17O NMR study of α-d-glucose: exploring new frontiers in isotopic labeling, sensitivity enhancement, and NMR crystallography. Chem Sci 2022; 13:2591-2603. [PMID: 35340864 PMCID: PMC8890099 DOI: 10.1039/d1sc06060k] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/31/2021] [Indexed: 01/03/2023] Open
Abstract
We report the first “total synthesis” of 17O-labeled d-glucose and its solid-state 17O NMR characterization with unprecedented sensitivity and resolution.
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Affiliation(s)
- Jiahui Shen
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
| | - Victor Terskikh
- Metrology, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Jochem Struppe
- Bruker Biospin Corporation, 15 Fortune Drive, Billerica, MA 01821, USA
| | - Alia Hassan
- Bruker Switzerland AG, Fällanden, Switzerland
| | - Martine Monette
- Bruker Biospin Ltd., 2800 High Point Drive, Suite 206, Milton, Ontario L9T 6P4, Canada
| | - Ivan Hung
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| | - Zhehong Gan
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| | - Andreas Brinkmann
- Metrology, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Gang Wu
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
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2
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Abstract
Quantitative 1H nuclear magnetic resonance (qHNMR) with an appropriate internal standard is a well-established quantitation method for assigning purity to organic molecules. For accurate measurements, the premise of qHNMR relies on the careful selection of integrals, for both the analyte and the standard, in such a way that the selected integrals are free from interferences. The 13C-satellite signals of adjacent integrals, low-level impurities, and tautomer signals are among the common integral interferences that are typically encountered. One of the simplest ways to identify and avoid these interferences is to decouple the 13C-satellites. Two decoupling schemes were explored to illustrate the benefits of 13C-decoupling for qHNMR or qH{13C}NMR: GARP and bilevel adiabatic broadband decoupling. Unwanted sample heating and nuclear Overhauser effect (NOE) enhancements are the two main drawbacks of decoupling schemes. We show that with careful optimization of acquisition parameters and decoupling power, no excessive sample heating occurred during acquisition at 400 MHz. At 900 MHz, only bilevel adiabatic decoupling could be safely implemented. Furthermore, any undesirable NOE enhancements were completely avoided if acquisition was executed with an inverse-gated pulse sequence. We explored and confirmed the benefits of qH{13C}NMR through the quantitation of a diverse set of compounds, namely, small molecules (dimethyl terephthalate and zearalenone), a 13C-labeled compound (13C6-ochratoxin A), and an octapeptide (angiotensin II). Statistical comparisons confirmed that qH{13C}NMR produced comparable data to qHNMR. However, with qH{13C}NMR data providing added clarity about the presence of overlapping 13C-satellites, impurities, and tautomers, it has an edge over qHNMR for accurate measurements.
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Affiliation(s)
- Adilah Bahadoor
- Metrology, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Andreas Brinkmann
- Metrology, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Jeremy E Melanson
- Metrology, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
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3
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Richter DC, Brenner T, Brinkmann A, Grabein B, Hochreiter M, Heininger A, Störzinger D, Briegel J, Pletz M, Weigand MA, Lichtenstern C. [New antibiotics for severe infections due to multidrug-resistant pathogens : Definitive treatment and escalation]. Anaesthesist 2020; 68:785-800. [PMID: 31555832 DOI: 10.1007/s00101-019-00646-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 12/12/2022]
Abstract
Multidrug-resistant pathogens often lead to treatment failure of antimicrobial regimens. After a period of imbalance between the occurrence/spread of resistance mechanisms and the development of new substances, some new substances have meanwhile been approved and many more are currently undergoing clinical testing. They are particularly effective against specific resistance mechanisms/pathogens and should be preserved for definitive treatment of an isolated pathogen. In the absence of alternatives reserve antibiotics, such as aztreonam and colistin have experienced a renaissance. They are again used in special infection scenarios and clinically tested in combination with new substances. Despite the introduction and development of new substances the building of resistance will at some time also render these (at least partially) ineffective. Therefore, their implementation must be carried out according to the antibiotic or infectious diseases stewardship.
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Affiliation(s)
- D C Richter
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland.
| | - T Brenner
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
| | - A Brinkmann
- Klinik für Anästhesie, operative Intensivmedizin und spezielle Schmerztherapie, Klinikum Heidenheim, Heidenheim, Deutschland
| | - B Grabein
- Stabsstelle "Klinische Mikrobiologie und Krankenhaushygiene", Klinikum der Universität München, München, Deutschland
| | - M Hochreiter
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
| | - A Heininger
- Zentrum für Infektiologie, Sektion für Krankenhaus- und Umwelthygiene, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - D Störzinger
- Apotheke, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - J Briegel
- Klinik für Anästhesiologie, Ludwig-Maximilians-Universität, München, Deutschland
| | - M Pletz
- Institut für Infektionsmedizin und Krankenhaushygiene, Universitätsklinikum Jena, Jena, Deutschland
| | - M A Weigand
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
| | - C Lichtenstern
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
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4
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Kunc F, Kodra O, Brinkmann A, Lopinski GP, Johnston LJ. A Multi-Method Approach for Quantification of Surface Coatings on Commercial Zinc Oxide Nanomaterials. Nanomaterials (Basel) 2020; 10:E678. [PMID: 32260261 PMCID: PMC7221730 DOI: 10.3390/nano10040678] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/25/2020] [Accepted: 03/29/2020] [Indexed: 01/24/2023]
Abstract
Surface functionalization is a key factor for determining the performance of nanomaterials in a range of applications and their fate when released to the environment. Nevertheless, it is still relatively rare that surface groups or coatings are quantified using methods that have been carefully optimized and validated with a multi-method approach. We have quantified the surface groups on a set of commercial ZnO nanoparticles modified with three different reagents ((3-aminopropyl)-triethoxysilane, caprylsilane and stearic acid). This study used thermogravimetric analysis (TGA) with Fourier transform infrared spectroscopy (FT-IR) of evolved gases and quantitative solution 1H nuclear magnetic resonance (NMR) for quantification purposes with 13C-solid state NMR and X-ray photoelectron spectroscopy to confirm assignments. Unmodified materials from the same suppliers were examined to assess possible impurities and corrections. The results demonstrate that there are significant mass losses from the unmodified samples which are attributed to surface carbonates or residual materials from the synthetic procedure used. The surface modified materials show a characteristic loss of functional group between 300-600 °C as confirmed by analysis of FT-IR spectra and comparison to NMR data obtained after quantitative release/extraction of the functional group from the surface. The agreement between NMR and TGA estimates for surface loading is reasonably good for cases where the functional group accounts for a relatively large fraction of the sample mass (e.g., large groups or high loading). In other cases TGA does not have sufficient sensitivity for quantitative analysis, particularly when contaminants contribute to the TGA mass loss. X-ray photoelectron spectroscopy and solid state NMR for selected samples provide support for the assignment of both the functional groups and some impurities. The level of surface group loading varies significantly with supplier and even for different batches or sizes of nanoparticles from the same supplier. These results highlight the importance of developing reliable methods to detect and quantify surface functional groups and the importance of a multi-method approach.
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Affiliation(s)
| | | | | | - Gregory P. Lopinski
- National Research Council Canada, Ottawa, ON K1A 0R6, Canada; (F.K.); (O.K.); (A.B.)
| | - Linda J. Johnston
- National Research Council Canada, Ottawa, ON K1A 0R6, Canada; (F.K.); (O.K.); (A.B.)
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5
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Brinkmann A, Röhr AC, Frey OR, Krüger WA, Brenner T, Richter DC, Bodmann KF, Kresken M, Grabein B. [S2k guidelines of the PEG on calculated parenteral initial treatment of bacterial diseases in adults : Focussed summary and supplementary information on antibiotic treatment of critically ill patients]. Anaesthesist 2019; 67:936-949. [PMID: 30511110 DOI: 10.1007/s00101-018-0512-8] [Citation(s) in RCA: 15] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In January 2018 the recent revision of the S2k guidelines on calculated parenteral initial treatment of bacterial diseases in adults-update 2018 (Editor: Paul Ehrlich Society for Chemotherapy, PEG) was realized. It is a helpful tool for the complex infectious disease setting in an intensive care unit. The present summary of the guidelines focuses on the topics of anti-infective agents, including new substances, pharmacokinetics and pharmacodynamics as well as on microbiology, resistance development and recommendations for calculated drug therapy in septic patients. As in past revisions the recent resistance situation and results of new clinical studies are considered and anti-infective agents are summarized in a table.
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Affiliation(s)
- A Brinkmann
- Klinik für Anästhesie, operative Intensivmedizin und spezielle Schmerztherapie, Klinikum Heidenheim, Schlosshaustraße 100, 89522, Heidenheim, Deutschland.
| | - A C Röhr
- Apotheke, Klinikum Heidenheim, Heidenheim, Deutschland
| | - O R Frey
- Apotheke, Klinikum Heidenheim, Heidenheim, Deutschland
| | - W A Krüger
- Klinik für Anästhesiologie und Operative Intensivmedizin, Klinikum Konstanz, Konstanz, Deutschland
| | - T Brenner
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - D C Richter
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - K-F Bodmann
- Klinik für Internistische Intensiv- und Notfallmedizin und Klinische Infektiologie, Klinikum Barnim GmbH, Werner Forßmann Krankenhaus, Eberswalde, Deutschland
| | - M Kresken
- Antiinfectives Intelligence GmbH, Campus Rheinbach, Hochschule Bonn-Rhein-Sieg, Rheinbach, Deutschland.,Rheinische Fachhochschule Köln gGmbH, Köln, Deutschland
| | - B Grabein
- Stabsstelle Klinische Mikrobiologie und Krankenhaushygiene, Klinikum der Universität München, Campus Großhadern, München, Deutschland
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6
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Brinkmann A, Röhr AC, Köberer A, Fuchs T, Krüger WA, König C, Richter D, Weigand MA, Frey OR. [Adequate anti-infective treatment : Importance of individual dosing and application]. Anaesthesist 2019; 67:461-476. [PMID: 29766208 DOI: 10.1007/s00101-018-0443-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Sepsis-induced changes in pharmacokinetic parameters are a well-known problem in intensive care medicine. Dosing of antibiotics in this setting is therefore challenging. Alterations to the substance-specific kinetics of anti-infective substances have an effect on the distribution and excretion processes in the body. Increased clearance and an increased distribution volume (Vd) and particularly compromized organ function with reduced antibiotic elimination are often encountered in patients with sepsis. Renal replacement treatment, which is frequently used in intensive care medicine, represents a substantial intervention in this system. Current international guidelines recommend individualized dosing strategies and adaptation of doses according to measured serum levels and pharmacokinetic/pharmacodynamic (PK/PD) parameters as concepts to optimize anti-infective therapy in the critically ill. Likewise, the recommendation to adjust the administration form of beta-lactam antibiotics to prolonged or continuous infusion can be found increasingly more often in the literature. This article reviews the background of the individual dosing in intensive care patients and their applicability to the clinical routine.
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Affiliation(s)
- A Brinkmann
- Klinik für Anästhesie, operative Intensivmedizin und spezielle Schmerztherapie, Klinikum Heidenheim, Schlosshaustr. 100, 89522, Heidenheim, Deutschland.
| | - A C Röhr
- Apotheke, Klinikum Heidenheim, Heidenheim, Deutschland
| | - A Köberer
- Klinik für Anästhesie, operative Intensivmedizin und spezielle Schmerztherapie, Klinikum Heidenheim, Schlosshaustr. 100, 89522, Heidenheim, Deutschland
| | - T Fuchs
- Klinik für Anästhesie, operative Intensivmedizin und spezielle Schmerztherapie, Klinikum Heidenheim, Schlosshaustr. 100, 89522, Heidenheim, Deutschland
| | - W A Krüger
- Klinik für Anästhesiologie und Operative Intensivmedizin, Klinikum Konstanz, Konstanz, Deutschland
| | - C König
- Klinik für Intensivmedizin, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Deutschland.,Klinikapotheke, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Deutschland
| | - D Richter
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - M A Weigand
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - O R Frey
- Apotheke, Klinikum Heidenheim, Heidenheim, Deutschland
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7
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Kunc F, Balhara V, Sun Y, Daroszewska M, Jakubek ZJ, Hill M, Brinkmann A, Johnston LJ. Quantification of surface functional groups on silica nanoparticles: comparison of thermogravimetric analysis and quantitative NMR. Analyst 2019; 144:5589-5599. [PMID: 31418443 DOI: 10.1039/c9an01080g] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Thermogravimetric analysis (TGA) coupled with evolved gas analysis-FT-IR has been examined as a potential method to study the functional group content for surface modified silica nanoparticles. A comparison with a quantitative solution NMR method based on analysis of groups released after dissolution of the silica matrix is used to provide benchmark data for comparison and to assess the utility and limitations of TGA. This study focused primarily on commercially available silicas and tested whether it was possible to use a correction based on bare silica to account for the significant mass loss that occurs due to condensation of surface hydroxyl groups and loss of matrix-entrapped components at temperatures above ∼200 °C. Although this approach has been used successfully in the literature for in-house prepared samples, it was problematic for commercial silicas prepared by the Stöber method. For these materials the agreement between estimates from qNMR and TGA mass loss was poor in many cases. However much better agreement was observed for samples for which the mass loss above 200 °C is relatively low, such as non-porous silica, or samples for which the mass fraction of functional group is large (e.g., high molecule weight groups or multilayers). FT-IR was useful in identifying the likely structure of the components lost from the surface at various temperatures and in some cases provided evidence of contaminants in the sample. Nevertheless, in other cases correlation of thermograms and FT-IR with NMR data was necessary, particularly for samples where multi-step modification of the silica surface results in incomplete functionalization that gives a mixture of products. Overall the results indicate that TGA provides reliable results for silicas of low porosity or those for which the functional group accounts for a significant fraction of the total sample mass. It is also suitable as a supplementary or screening technique to indicate the presence of coatings or covalent surface modification, prior to applying other techniques or for routine analyses where sensitivity is not critical.
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Affiliation(s)
- Filip Kunc
- National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada.
| | - Vinod Balhara
- National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada.
| | - Ying Sun
- National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada.
| | | | | | - Myriam Hill
- New Substances Assessment & Control Bureau, Health Canada, Ottawa, Ontario K1A 0K9, Canada
| | | | - Linda J Johnston
- National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada.
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8
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Wasylishen RE, Matlinska MA, Bernard GM, Terskikh VV, Brinkmann A. Hydrogen-bonding in the enol tautomer of 1,3-diketones: insights from 2/1H isotope effects on NMR parameters in the solid state as well as computational chemistry. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s0108767319097149] [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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9
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Sun Y, Kunc F, Balhara V, Coleman B, Kodra O, Raza M, Chen M, Brinkmann A, Lopinski GP, Johnston LJ. Quantification of amine functional groups on silica nanoparticles: a multi-method approach. Nanoscale Adv 2019; 1:1598-1607. [PMID: 36132607 PMCID: PMC9417554 DOI: 10.1039/c9na00016j] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/21/2019] [Indexed: 05/08/2023]
Abstract
Surface chemistry is an important factor for quality control during production of nanomaterials and for controlling their behavior in applications and when released into the environment. Here we report a comparison of four methods for quantifying amine functional groups on silica nanoparticles (NPs). Two colorimetric assays are examined, ninhydrin and 4-nitrobenzaldehyde, which are convenient for routine analysis and report on reagent accessible amines. Results from the study of a range of commercial NPs with different sizes and surface loadings show that the assays account for 50-100% of the total amine content, as determined by dissolution of NPs under basic conditions and quantification by solution-state 1H NMR. To validate the surface quantification by the colorimetric assays, the NPs are modified with a trifluoromethylated benzaldehyde probe to enhance sensitivity for quantitative 19F solid state NMR and X-ray photoelectron spectroscopy (XPS). Good agreement between the assays and the determination from solid-state NMR is reinforced by elemental ratios from XPS, which indicate that in most cases the difference between total and accessible amine content reflects amines that are outside the depth probed by XPS. Overall the combined results serve to validate the relatively simple colorimetric assays and indicate that the reactions are efficient at quantifying surface amines, by contrast to some other covalent modifications that have been employed for functional group quantification.
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Affiliation(s)
- Ying Sun
- National Research Council Canada Ottawa ON Canada K1A 0R6
| | - Filip Kunc
- National Research Council Canada Ottawa ON Canada K1A 0R6
| | - Vinod Balhara
- National Research Council Canada Ottawa ON Canada K1A 0R6
| | - Brian Coleman
- National Research Council Canada Ottawa ON Canada K1A 0R6
| | - Oltion Kodra
- National Research Council Canada Ottawa ON Canada K1A 0R6
| | - Mohammad Raza
- National Research Council Canada Ottawa ON Canada K1A 0R6
| | - Maohui Chen
- National Research Council Canada Ottawa ON Canada K1A 0R6
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10
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Brinkmann A, Hekimoğlu O, Dincer E, Hagedorn P, Nitsche A, Ergünay K. A metagenomic survey of ticks reveals pathogenic rickettsia and francisella/coxiella-like endosymbionts in Anatolia. Int J Infect Dis 2019. [DOI: 10.1016/j.ijid.2018.11.355] [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: 10/27/2022] Open
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11
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Brinkmann A, Sternberg U, Bovee-Geurts PHM, Fernández Fernández I, Lugtenburg J, Kentgens APM, DeGrip WJ. Insight into the chromophore of rhodopsin and its Meta-II photointermediate by 19F solid-state NMR and chemical shift tensor calculations. Phys Chem Chem Phys 2018; 20:30174-30188. [PMID: 30484791 DOI: 10.1039/c8cp05886e] [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: 11/21/2022]
Abstract
19F nuclei are useful labels in solid-state NMR studies, since their chemical shift and tensor elements are very sensitive to the electrostatic and space-filling properties of their local environment. In this study we have exploited a fluorine substituent, strategically placed at the C-12-position of 11-cis retinal, the chromophore of visual rhodopsins. This label was used to explore the local environment of the chromophore in the ground state of bovine rhodopsin and its active photo-intermediate Meta II. In addition, the chemical shift and tensor elements of the chromophore in the free state in a membrane environment and the bound state in the protein were determined. Upon binding of the chromophore into rhodopsin and Meta II, the isotropic chemical shift changes in the opposite direction by +9.7 and -8.4 ppm, respectively. An unusually large isotropic shift difference of 35.9 ppm was observed between rhodopsin and Meta II. This partly originates in the light-triggered 11-cis to all-trans isomerization of the chromophore. The other part reflects the local conformational rearrangements in the chromophore and the binding pocket. These NMR data were correlated with the available X-ray structures of rhodopsin and Meta II using bond polarization theory. For this purpose hydrogen atoms have to be inserted and hereto a family of structures were derived that best correlated with the well-established 13C chemical shifts. Based upon these structures, a 12-F derivative was obtained that best corresponded with the experimentally determined 19F chemical shifts and tensor elements. The combined data indicate strong changes in the local environment of the C-12 position and a substantially different interaction pattern with the protein in Meta II as compared to rhodopsin.
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Affiliation(s)
- Andreas Brinkmann
- Metrology, National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada.
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12
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Kunc F, Balhara V, Brinkmann A, Sun Y, Leek DM, Johnston LJ. Quantification and Stability Determination of Surface Amine Groups on Silica Nanoparticles Using Solution NMR. Anal Chem 2018; 90:13322-13330. [DOI: 10.1021/acs.analchem.8b02803] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Filip Kunc
- National Research Council Canada, Metrology Research Centre, Ottawa, Ontario K1A 0R6, Canada
| | - Vinod Balhara
- National Research Council Canada, Metrology Research Centre, Ottawa, Ontario K1A 0R6, Canada
| | - Andreas Brinkmann
- National Research Council Canada, Metrology Research Centre, Ottawa, Ontario K1A 0R6, Canada
| | - Ying Sun
- National Research Council Canada, Metrology Research Centre, Ottawa, Ontario K1A 0R6, Canada
| | - Donald M. Leek
- National Research Council Canada, Metrology Research Centre, Ottawa, Ontario K1A 0R6, Canada
| | - Linda J. Johnston
- National Research Council Canada, Metrology Research Centre, Ottawa, Ontario K1A 0R6, Canada
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13
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Richter DC, Heininger A, Brenner T, Hochreiter M, Bernhard M, Briegel J, Dubler S, Grabein B, Hecker A, Krüger WA, Mayer K, Pletz MW, Störzinger D, Pinder N, Hoppe-Tichy T, Weiterer S, Zimmermann S, Brinkmann A, Weigand MA, Lichtenstern C. [Bacterial sepsis : Diagnostics and calculated antibiotic therapy]. Anaesthesist 2018; 66:737-761. [PMID: 28980026 DOI: 10.1007/s00101-017-0363-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The mortality of patients with sepsis and septic shock is still unacceptably high. An effective antibiotic treatment within 1 h of recognition of sepsis is an important target of sepsis treatment. Delays lead to an increase in mortality; therefore, structured treatment concepts form a rational foundation, taking relevant diagnostic and treatment steps into consideration. In addition to the assumed focus and individual risks of each patient, local resistance patterns and specific problem pathogens must be taken into account for selection of anti-infection treatment. Many pathophysiological alterations influence the pharmacokinetics of antibiotics during sepsis. The principle of standard dosing should be abandoned and replaced by an individual treatment approach with stronger weighting of the pharmacokinetics/pharmacodynamics (PK/PD) index of the substance groups. Although this is not yet the clinical standard, prolonged (or continuous) infusion of beta-lactam antibiotics and therapeutic drug monitoring (TDM) can help to achieve defined PK targets. Prolonged infusion is sufficient without TDM but for continuous infusion TDM is basically necessary. A further argument for individual PK/PD-oriented antibiotic approaches is the increasing number of infections due to multidrug resistant pathogens (MDR) in the intensive care unit. For effective treatment antibiotic stewardship teams (ABS team) are becoming more established. Interdisciplinary cooperation of the ABS team with infectiologists, microbiologists and clinical pharmacists leads not only to a rational administration of antibiotics but also has a positive influence on the outcome. The gold standards for pathogen detection are still culture-based detection and microbiological resistance testing for the various antibiotic groups. Despite the rapid investigation time, novel polymerase chain reaction (PCR)-based procedures for pathogen identification and resistance determination, are currently only an adjunct to routine sepsis diagnostics due to the limited number of studies, high costs and limited availability. In complicated septic courses with multiple anti-infective treatment or recurrent sepsis, PCR-based procedures can be used in addition to therapy monitoring and diagnostics. Novel antibiotics represent potent alternatives in the treatment of MDR infections. Due to the often defined spectrum of pathogens and the practically absent resistance, they are suitable for targeted treatment of severe MDR infections (therapy escalation).
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Affiliation(s)
- D C Richter
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland.
| | - A Heininger
- Zentrum für Infektiologie, Sektion für Krankenhaus- und Umwelthygiene, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - T Brenner
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
| | - M Hochreiter
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
| | - M Bernhard
- Zentrale Notaufnahme, Universitätsklinikum Leipzig, Leipzig, Deutschland
| | - J Briegel
- Klinik für Anästhesiologie, Klinikum der Universität München, München, Deutschland
| | - S Dubler
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
| | - B Grabein
- Stabsstelle "Klinische Mikrobiologie und Krankenhaushygiene", Klinikum der Universität München, München, Deutschland
| | - A Hecker
- Klinik für Allgemein‑, Viszeral‑, Thorax‑, Transplantations- und Kinderchirurgie, Universitätsklinikum Gießen und Marburg, Standort Gießen, Gießen, Deutschland
| | - W A Krüger
- Klinik für Anästhesiologie und operative Intensivmedizin, Gesundheitsverbund Landkreis Konstanz, Klinikum Konstanz, Konstanz, Deutschland
| | - K Mayer
- Apotheke des Universitätsklinikums Heidelberg, Heidelberg, Deutschland
| | - M W Pletz
- Zentrum für Infektionsmedizin und Krankenhaushygiene, Universitätsklinikum Jena, Jena, Deutschland
| | - D Störzinger
- Apotheke des Universitätsklinikums Heidelberg, Heidelberg, Deutschland
| | - N Pinder
- Apotheke des Universitätsklinikums Heidelberg, Heidelberg, Deutschland
| | - T Hoppe-Tichy
- Zentrum für Infektiologie, Sektion für Krankenhaus- und Umwelthygiene, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - S Weiterer
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
| | - S Zimmermann
- Zentrum für Infektiologie, Sektion für Krankenhaus- und Umwelthygiene, Universitätsklinikum Heidelberg, Heidelberg, Deutschland
| | - A Brinkmann
- Klinik für Anästhesie, operative Intensivmedizin und spezielle Schmerztherapie, Klinikum Heidenheim, Heidenheim, Deutschland
| | - M A Weigand
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
| | - Christoph Lichtenstern
- Klinik für Anästhesiologie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Deutschland
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14
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Benschop HOG, Guerin AJ, Brinkmann A, Dale ML, Finnie AA, Breugem WP, Clare AS, Stübing D, Price C, Reynolds KJ. Drag-reducing riblets with fouling-release properties: development and testing. Biofouling 2018; 34:532-544. [PMID: 29806493 DOI: 10.1080/08927014.2018.1469747] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/19/2018] [Indexed: 06/08/2023]
Abstract
The manufacture and preliminary testing of a drag-reducing riblet texture with fouling-control properties is presented. The commercial fouling-release product Intersleek® 1100SR was modified to manufacture riblet-textured coatings with an embossing technology. Hydrodynamic drag measurements in a Taylor-Couette set-up showed that the modified Intersleek® riblets reduced drag by up to 6% compared to a smooth surface. Barnacle settlement assays demonstrated that the riblets did not substantially reduce the ability of Intersleek® 1100SR to prevent fouling by cyprids of Balanus amphitrite. Diatom adhesion tests revealed significantly higher diatom attachment on the riblet surface compared to smooth Intersleek® 1100SR. However, after exposure to flow, the final cell density was similar to the smooth surface. Statically immersed panels in natural seawater showed an increase of biofilm cover due to the riblets. However, the release of semi-natural biofilms grown in a multi-species biofilm culturing reactor was largely unaffected by the presence of a riblet texture.
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Affiliation(s)
- H O G Benschop
- a Laboratory for Aero and Hydrodynamics , Delft University of Technology , Delft , the Netherlands
| | - A J Guerin
- b School of Natural and Environmental Sciences , Newcastle University , Newcastle upon Tyne , UK
| | - A Brinkmann
- c Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM , Bremen , Germany
| | - M L Dale
- d AkzoNobel/International Paint Ltd , Gateshead , UK
| | - A A Finnie
- d AkzoNobel/International Paint Ltd , Gateshead , UK
| | - W-P Breugem
- a Laboratory for Aero and Hydrodynamics , Delft University of Technology , Delft , the Netherlands
| | - A S Clare
- b School of Natural and Environmental Sciences , Newcastle University , Newcastle upon Tyne , UK
| | - D Stübing
- c Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM , Bremen , Germany
| | - C Price
- d AkzoNobel/International Paint Ltd , Gateshead , UK
| | - K J Reynolds
- d AkzoNobel/International Paint Ltd , Gateshead , UK
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15
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Wittmer A, Brinkmann A, Stenzel V, Hartwig A, Koschek K. Moisture-mediated intrinsic self-healing of modified polyurethane urea polymers. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/pola.28925] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Anastassija Wittmer
- Fraunhofer Institute for Manufacturing Technology and Advanced Materials, IFAM, Wiener Straße 12; Bremen 28359 Germany
- Chemical Department; University of Bremen, Leobener Str; Bremen D-28359 Germany
| | - Andreas Brinkmann
- Fraunhofer Institute for Manufacturing Technology and Advanced Materials, IFAM, Wiener Straße 12; Bremen 28359 Germany
| | - Volkmar Stenzel
- Fraunhofer Institute for Manufacturing Technology and Advanced Materials, IFAM, Wiener Straße 12; Bremen 28359 Germany
| | - Andreas Hartwig
- Fraunhofer Institute for Manufacturing Technology and Advanced Materials, IFAM, Wiener Straße 12; Bremen 28359 Germany
- Chemical Department; University of Bremen, Leobener Str; Bremen D-28359 Germany
| | - Katharina Koschek
- Fraunhofer Institute for Manufacturing Technology and Advanced Materials, IFAM, Wiener Straße 12; Bremen 28359 Germany
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16
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Brinkmann A, O'Dell LA. Optimisation of excitation schemes for 14N overtone MAS NMR using numerically exact simulations. Solid State Nucl Magn Reson 2017; 84:34-40. [PMID: 27986400 DOI: 10.1016/j.ssnmr.2016.12.006] [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] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/08/2016] [Accepted: 12/08/2016] [Indexed: 06/06/2023]
Abstract
Numerically exact simulations of the 14N overtone (14NOT) MAS NMR experiment are used to investigate the effects of the applied magnetic field strength as well as three types of excitation pulse. The results show that both the resolution and sensitivity of 14NOT MAS NMR increase linearly with the applied static magnetic field strength. Standard RF excitation pulses are compared with frequency-swept WURST pulses as well as several composite pulses. WURST pulses are demonstrated to provide the largest bandwidths, while the direction of the frequency sweep is shown to be important when these pulses are used for the direct observation of 14NOT signals. A composite pulse is shown to provide the most efficient excitation overall, but only when applied on resonance. WURST excitation pulses are therefore the best option when studying a sample with unknown 14N NMR parameters.
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Affiliation(s)
- Andreas Brinkmann
- Measurement Science and Standards, National Research Council Canada, 1200 Montreal Road, M40, Ottawa, Ontario, Canada K1A 0R6
| | - Luke A O'Dell
- Institute for Frontier Materials, Deakin University, Waurn Ponds Campus, Geelong, Victoria 3220, Australia.
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17
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Lu J, Hung I, Brinkmann A, Gan Z, Kong X, Wu G. Solid-State 17 O NMR Reveals Hydrogen-Bonding Energetics: Not All Low-Barrier Hydrogen Bonds Are Strong. Angew Chem Int Ed Engl 2017; 56:6166-6170. [PMID: 28225158 DOI: 10.1002/anie.201700488] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Indexed: 11/07/2022]
Abstract
While NMR and IR spectroscopic signatures and structural characteristics of low-barrier hydrogen bond (LBHB) formation are well documented in the literature, direct measurement of the LBHB energy is difficult. Here, we show that solid-state 17 O NMR spectroscopy can provide unique information about the energy required to break a LBHB. Our solid-state 17 O NMR data show that the HB enthalpy of the O⋅⋅⋅H⋅⋅⋅N LBHB formed in crystalline nicotinic acid is only 7.7±0.5 kcal mol-1 , suggesting that not all LBHBs are particularly strong.
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Affiliation(s)
- Jiasheng Lu
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, K7L 3N6, Canada
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL, 32310, USA
| | - Andreas Brinkmann
- Measurement Science and Standards, National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario, K1A 0R6, Canada
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL, 32310, USA
| | - Xianqi Kong
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, K7L 3N6, Canada
| | - Gang Wu
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, K7L 3N6, Canada
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18
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Lu J, Hung I, Brinkmann A, Gan Z, Kong X, Wu G. Solid‐State
17
O NMR Reveals Hydrogen‐Bonding Energetics: Not All Low‐Barrier Hydrogen Bonds Are Strong. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700488] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jiasheng Lu
- Department of Chemistry Queen's University 90 Bader Lane Kingston Ontario K7L 3N6 Canada
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance National High Magnetic Field Laboratory 1800 East Paul Dirac Drive Tallahassee FL 32310 USA
| | - Andreas Brinkmann
- Measurement Science and Standards National Research Council Canada 1200 Montreal Road Ottawa Ontario K1A 0R6 Canada
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance National High Magnetic Field Laboratory 1800 East Paul Dirac Drive Tallahassee FL 32310 USA
| | - Xianqi Kong
- Department of Chemistry Queen's University 90 Bader Lane Kingston Ontario K7L 3N6 Canada
| | - Gang Wu
- Department of Chemistry Queen's University 90 Bader Lane Kingston Ontario K7L 3N6 Canada
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19
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Ergunay K, Litzba N, Brinkmann A, Gunay F, Kar S, Oter K, Orsten S, Alten B, Nitsche A, Linton YM. Characterization of a Culex theileri flavivirus variant in field-collected mosquitoes from Turkey. Int J Infect Dis 2016. [DOI: 10.1016/j.ijid.2016.11.302] [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: 11/25/2022] Open
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20
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Kong X, Brinkmann A, Terskikh V, Wasylishen RE, Bernard GM, Duan Z, Wu Q, Wu G. Proton Probability Distribution in the O···H···O Low-Barrier Hydrogen Bond: A Combined Solid-State NMR and Quantum Chemical Computational Study of Dibenzoylmethane and Curcumin. J Phys Chem B 2016; 120:11692-11704. [PMID: 27782387 DOI: 10.1021/acs.jpcb.6b08091] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a combined solid-state (1H, 2H, 13C, 17O) NMR and plane-wave density functional theory (DFT) computational study of the O···H···O low-barrier hydrogen bonds (LBHBs) in two 1,3-diketone compounds: dibenzoylmethane (1) and curcumin (2). In the solid state, both 1 and 2 exist in the cis-keto-enol tautomeric form, each exhibiting an intramolecular LBHB with a short O···O distance (2.435 Å in 1 and 2.455 Å in 2). Whereas numerous experimental (structural and spectroscopic) and computational studies have been reported for the enol isomers of 1,3-diketones, a unified picture about the proton location within an LBHB is still lacking. This work reports for the first time the solid-state 17O NMR data for the O···H···O LBHBs in 1,3-diketones. The central conclusion of this work is that detailed information about the probability density distribution of the proton (nuclear zero-point motion) across an LBHB can be obtained from a combination of solid-state NMR and plane-wave DFT computations (both NMR parameter calculations and ab initio molecular dynamics simulations). We propose that the precise proton probability distribution across an LBHB should provide a common basis on which different and sometimes seemingly contradicting experimental results obtained from complementary techniques, such as X-ray diffraction, neutron diffraction, and solid-state NMR, can be reconciled.
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Affiliation(s)
- Xianqi Kong
- Department of Chemistry, Queen's University , 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
| | - Andreas Brinkmann
- Measurement Science and Standards, National Research Council Canada , 1200 Montreal Road, M-40, Ottawa, Ontario, Canada K1A 0R6
| | - Victor Terskikh
- Department of Chemistry, Queen's University , 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6.,Department of Chemistry, University of Ottawa , 10 Marie Curie Private, Ottawa, Ontario, Canada K1N 6N5
| | | | - Guy M Bernard
- Department of Chemistry, University of Alberta , Edmonton, Alberta, Canada T6G 2G2
| | - Zhuang Duan
- Department of Chemistry, University of Alberta , Edmonton, Alberta, Canada T6G 2G2
| | - Qichao Wu
- Department of Chemistry, University of Alberta , Edmonton, Alberta, Canada T6G 2G2
| | - Gang Wu
- Department of Chemistry, Queen's University , 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
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21
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Brinkmann A, Röhr AC, Köberer A, Fuchs T, Preisenberger J, Krüger WA, Frey OR. [Therapeutic drug monitoring and individual dosing of antibiotics during sepsis : Modern or just "trendy"?]. Med Klin Intensivmed Notfmed 2016; 113:82-93. [PMID: 27624768 DOI: 10.1007/s00063-016-0213-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 05/31/2016] [Accepted: 06/13/2016] [Indexed: 01/25/2023]
Abstract
Pharmacokinetic variability of anti-infective drugs due to pathophysiological changes by severe sepsis and septic shock is a well-known problem for critically ill patients resulting in suboptimal serum and most likely tissue concentrations of these agents.To cover a wide range of potential pathogens, high concentrations of broad spectrum anti-infectives have to reach the site of infection. Microbiological susceptibility testing (susceptible, intermediate, resistant) don't take the pharmacokinetic variability into account and are based on data generated by non-critically ill patients. But inter-patient variability in distribution and elimination of anti-infective drugs in ICU patients is extremely high and also highly unpredictable. Drug clearance of mainly renally eliminated drugs and thus the required dose can differ up to 10-fold due to the variability in renal function in patients with severe infections. To assure a timely and adequate anti-infective regime, individual dosing and therapeutic drug monitoring (TDM) seem to be appropriate tools in the setting of pathophysiological changes in pharmacokinetics (PK) and pharmakodynamics (PD) due to severe sepsis. In the case of known minimal inhibitory concentration, PK/PD indices (time or peak concentration dependent activity) and measured serum level can provide an optimal target concentration for the individual drug and patient.Modern anti-infective management for ICU patients includes more than the choice of drug and prompt application. Individual dosing, optimized prolonged infusion time and TDM give way to new and promising opportunities in infection control.
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Affiliation(s)
- A Brinkmann
- Klinik für Anästhesie, operative Intensivmedizin und spezielle Schmerztherapie, Klinikum Heidenheim, Schlosshaustraße 100, 89522, Heidenheim, Deutschland.
| | - A C Röhr
- Apotheke, Klinikum Heidenheim, Heidenheim, Deutschland
| | - A Köberer
- Klinik für Anästhesie, operative Intensivmedizin und spezielle Schmerztherapie, Klinikum Heidenheim, Schlosshaustraße 100, 89522, Heidenheim, Deutschland
| | - T Fuchs
- Klinik für Anästhesie, operative Intensivmedizin und spezielle Schmerztherapie, Klinikum Heidenheim, Schlosshaustraße 100, 89522, Heidenheim, Deutschland
| | | | - W A Krüger
- Klinik für Anästhesiologie und Operative Intensivmedizin, Klinikum Konstanz, Konstanz, Deutschland
| | - O R Frey
- Apotheke, Klinikum Heidenheim, Heidenheim, Deutschland
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22
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Brinkmann A, Chen M, Couillard M, Jakubek ZJ, Leng T, Johnston LJ. Correlating Cellulose Nanocrystal Particle Size and Surface Area. Langmuir 2016; 32:6105-6114. [PMID: 27228219 DOI: 10.1021/acs.langmuir.6b01376] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Cellulose nanocrystals (CNCs) are negatively charged nanorods that present challenges for characterization of particle size distribution and surface area-two of the common parameters for characterizing nanomaterials. CNC size distributions have been measured by two microscopy methods: atomic force microscopy (AFM) and transmission electron microscopy (TEM). The agreement between the two methods is good for length measurements, after taking into consideration tip-convolution effects for AFM. However, TEM widths are almost twice as large as AFM heights-an effect that we hypothesize is due to counting of a larger fraction of laterally associated CNCs in the TEM images. Overall, the difficulty of selecting individual particles for analysis and possible bias due to selection of a specific particle size during sample deposition are the main limitations associated with the microscopy measurements. The microscopy results were compared to Z-average data from dynamic light scattering, which is a useful method for routine analysis and for examining trends in size as a function of sample treatment. Measurements as a function of sonication energy were used to provide information on the presence of aggregates in the sample. Magic-angle-spinning solid-state NMR was employed to estimate the surface area of CNCs based on the ratio of integrated spectral intensities of resonances stemming from C4 sites at the crystallite surfaces and from all C4 sites. Our approach was adapted from the application of solid-state NMR to characterize larger cellulose microfibers and appears to provide a useful estimate that overcomes the limitations of using the BET method for measuring surface areas of highly aggregated nanomaterials. The solid-state NMR results show that the lateral dimension of the CNCs is consistent with that of elementary cellulose crystallites.
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Affiliation(s)
| | | | | | | | - Tianyang Leng
- Department of Chemistry, University of Ottawa , Ottawa, ON K1N 6N5, Canada
| | - Linda J Johnston
- Department of Chemistry, University of Ottawa , Ottawa, ON K1N 6N5, Canada
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23
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Brinkmann A, Braun JP, Riessen R, Dubb R, Kaltwasser A, Bingold TM. [Quality assurance concepts in intensive care medicine]. Med Klin Intensivmed Notfmed 2015; 110:575-80, 582-3. [PMID: 26497132 DOI: 10.1007/s00063-015-0095-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 08/19/2015] [Indexed: 11/25/2022]
Abstract
Intensive care medicine (ICM) is characterized by a high degree of complexity and requires intense communication and collaboration on interdisciplinary and multiprofessional levels. In order to achieve good quality of care in this environment and to prevent errors, a proactive quality and error management as well as a structured quality assurance system are essential. Since the early 1990s, German intensive care societies have developed concepts for quality management and assurance in ICM. In 2006, intensive care networks were founded in different states to support the implementation of evidence-based knowledge into clinical routine and to improve medical outcome, efficacy, and efficiency in ICM. Current instruments and concepts of quality assurance in German ICM include core intensive care data from the data registry DIVI REVERSI, quality indicators, peer review in intensive care, IQM peer review, and various certification processes. The first version of German ICM quality indicators was published in 2010 by an interdisciplinary and interprofessional expert commission. Key figures, indicators, and national benchmarks are intended to describe the quality of structures, processes, and outcomes in intensive care. Many of the quality assurance tools have proved to be useful in clinical practice, but nationwide implementation still can be improved.
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Affiliation(s)
- A Brinkmann
- Klinik für Anästhesiologie, operative Intensivmedizin und spezielle Schmerztherapie, Klinikum Heidenheim, gGmbH, Schlosshaustraße 100, 89522, Heidenheim, Deutschland.
| | - J P Braun
- Klinik für Anästhesie, Intensivmedizin und Schmerztherapie, Helios Klinikum Hildesheim, Hildesheim, Deutschland
| | - R Riessen
- Internistische Intensivstation, Department für Innere Medizin, Universitätsklinikum Tübingen, Tübingen, Deutschland
| | - R Dubb
- Akademie der Kreiskliniken Reutlingen, Kreiskliniken Reutlingen GmbH, Reutlingen, Deutschland
| | - A Kaltwasser
- Akademie der Kreiskliniken Reutlingen, Kreiskliniken Reutlingen GmbH, Reutlingen, Deutschland
| | - T M Bingold
- Klinik für Anästhesiologie, Intensivmedizin und Schmerztherapie, Universitätsklinikum Frankfurt, Frankfurt/Main, Deutschland
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Brinkmann A, Edén M. Central-transition double-quantum sideband NMR spectroscopy of half-integer quadrupolar nuclei: estimating internuclear distances and probing clusters within multi-spin networks. Phys Chem Chem Phys 2014; 16:7037-50. [DOI: 10.1039/c4cp00029c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Clusters within quadrupolar spin networks are probed and internuclear distances between quadrupolar nuclei are estimated by central-transition double-quantum sideband NMR spectroscopy.
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Affiliation(s)
- Andreas Brinkmann
- Measurement Science and Standards
- National Research Council Canada
- Ottawa, Canada
| | - Mattias Edén
- Physical Chemistry Division
- Department of Materials and Environmental Chemistry
- Arrhenius Laboratory
- Stockholm University
- 106 91 Stockholm, Sweden
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25
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Bardelang D, Brinkmann A, Ratcliffe CI, Ripmeester JA, Terskikh VV, Udachin KA. High field solid state 13C NMR spectroscopy of cucurbituril materials. CrystEngComm 2014. [DOI: 10.1039/c3ce42467g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
It was recently shown that high resolution (14)N overtone NMR spectra can be obtained directly under magic angle spinning (MAS) conditions [L. A. O'Dell and C. I. Ratcliffe, Chem. Phys. Lett. 514, 168 (2011)]. Preliminary experimental results showed narrowed powder pattern widths, a frequency shift that is dependent on the MAS rate, and an apparent absence of spinning sidebands, observations which appeared to be inconsistent with previous theoretical treatments. Herein, we reproduce these effects using numerically exact simulations that take into account the full nuclear spin Hamiltonian. Under sample spinning, the (14)N overtone signal is split into five (0, ±1, ±2) overtone sidebands separated by the spinning frequency. For a powder sample spinning at the magic angle, the +2ω(r) sideband is dominant while the others show significantly lower signal intensities. The resultant MAS powder patterns show characteristic quadrupolar lineshapes from which the (14)N quadrupolar parameters and isotropic chemical shift can be determined. Spinning the sample at other angles is shown to alter both the shapes and relative intensities of the five overtone sidebands, with MAS providing the benefit of averaging dipolar couplings and shielding anisotropy. To demonstrate the advantages of this experimental approach, we present the (14)N overtone MAS spectrum obtained from L-histidine, in which powder patterns from all three nitrogen sites are clearly resolved.
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Affiliation(s)
- Luke A O'Dell
- Measurement Science and Standards, National Research Council Canada, 1200 Montreal Road, M40, Ottawa, Ontario K1A 0R6, Canada
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Nieuwland M, Ruizendaal L, Brinkmann A, Kroon-Batenburg L, van Hest JCM, Löwik DWPM. A structural study of the self-assembly of a palmitoyl peptide amphiphile. Faraday Discuss 2013; 166:360-79. [DOI: 10.1039/c3fd00055a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Kampschulte M, Schwab J, Brinkmann A, Gunkel I, Klaus M, Krombach GA, Langheinrich AC. Nano-CT zur Charakterisierung atherosklerotischer Plaque – Techniken und Ergebnisse. ROFO-FORTSCHR RONTG 2012. [DOI: 10.1055/s-0032-1329781] [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: 10/27/2022]
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29
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Bartels U, Brinkmann A, Ziegler M, Schmidt A. Eine schwere Aufgabe – adipöse Patienten in der Notfallmedizin. Notf Rett Med 2012. [DOI: 10.1007/s10049-011-1508-y] [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: 10/17/2022]
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Böer U, Brinkmann A, Jansen H, Martin Y, Haverich A, Wilhelmi M. Set-up and evaluation of an automated system for the efficient decellularization of equine carotid arteries as bioartificial vascular grafts. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4098] [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: 11/15/2022]
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31
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Birkenheuer G, Blunk D, Breuers S, Brinkmann A, dos Santos Vieira I, Fels G, Gesing S, Grunzke R, Herres-Pawlis S, Kohlbacher O, Kruber N, Krüger J, Lang U, Packschies L, Müller-Pfefferkorn R, Schäfer P, Schmalz HG, Steinke T, Warzecha KD, Wewior M. MoSGrid – a molecular simulation grid as a new tool in computational chemistry, biology and material science. J Cheminform 2011. [PMCID: PMC3083568 DOI: 10.1186/1758-2946-3-s1-p14] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Brinkmann A, Edén M. Estimating internuclear distances between half-integer quadrupolar nuclei by central-transition double-quantum sideband NMR spectroscopy. CAN J CHEM 2011. [DOI: 10.1139/v11-020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We demonstrate the estimation of homonuclear dipolar couplings, and thereby internuclear distances, between half-integer spin quadrupolar nuclei by central-transition (CT) double-quantum (2Q) sideband nuclear magnetic resonance (NMR) spectroscopy. It is shown that the rotor-encoded sideband amplitudes from CT 2Q coherences in the indirect dimension of the two-dimensional NMR spectrum are sensitive probes of the magnitude of the homonuclear dipolar coupling, but are significantly less affected by other NMR parameters such as the magnitudes and orientations of the electric field gradient tensors. Experimental results of employing the [Formula: see text] recoupling sequence to the 11B spin pair of bis(catecholato)diboron resulted in an estimation of the internuclear B–B distance as (169.6 ± 3) pm, i.e., with a relative uncertainty of ±2%, and in excellent agreement with the distance of 167.8 pm determined by single-crystal X-ray diffraction.
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Affiliation(s)
- Andreas Brinkmann
- Steacie Institute for Molecular Sciences, National Research Council, 1200 Montreal Road, M-40, Ottawa, ON K1A 0R6, Canada
| | - Mattias Edén
- Physical Chemistry Division, Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden
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Grimminck DL, Vasa SK, Meerts WL, Kentgens AP, Brinkmann A. EASY-GOING DUMBO on-spectrometer optimisation of phase modulated homonuclear decoupling sequences in solid-state NMR. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.04.079] [Citation(s) in RCA: 11] [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: 11/25/2022]
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Brinkmann A, Moritz R, Schneck E, Kline TL, Eaker DR, Gerlach SV, Bohle RM, Langheinrich AC, Lerman LO, Ritman EL. 3-Dimensional Structural and Volumetric Analysis of Glomeruli in Porcine Kidneys with Renal Artery Stenosis using Nano-Computed Tomography. ROFO-FORTSCHR RONTG 2011. [DOI: 10.1055/s-0031-1279297] [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: 10/18/2022]
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Kampschulte M, Gunkel I, Stieger P, Sedding D, Gerlach SV, Brinkmann A, Ritman EL, Langheinrich AC. Thalidomide inhibits Vasa Vasorum Neovascularization in Aortas of ApoE-/-/LDL-/- Double Knockout Mice. ROFO-FORTSCHR RONTG 2011. [DOI: 10.1055/s-0031-1279105] [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: 10/18/2022]
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Moritz R, Langheinrich AC, Kampschulte M, Brinkmann A, Stieger P, Sedding DG, Dierkes C, Bohle RM, Krombach G, Ritmann EL. Quantitative CT Imaging of the Spatio-Temporal Distribution Patterns of Vasa Vasorum in Aortas of ApoE-/-/LDL-/- double knockout Mice. ROFO-FORTSCHR RONTG 2010. [DOI: 10.1055/s-0030-1268327] [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: 10/18/2022]
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Kampschulte M, Brinkmann A, Stieger P, Sedding DG, Dierkes C, Bohle RM, Krombach G, Ritman EL, Langheinrich AC. Quantitative CT imaging of the spatio-temporal distribution patterns of vasa vasorum in aortas of apoE-/-/LDL-/- double knockout mice. Atherosclerosis 2010; 212:444-50. [PMID: 20692662 DOI: 10.1016/j.atherosclerosis.2010.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [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] [Received: 04/30/2010] [Revised: 06/30/2010] [Accepted: 07/07/2010] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To investigate the distribution of vasa vasorum (VV) relative to advanced atherosclerotic lesions (calcified, fibrotic or hemorrhaged) along the aortic wall of apoE-/-/LDL-/- mice at the age of 25 and 80 weeks using high-resolution nano-CT. METHODS Aortas from male apoE-/-/LDL-/- mice at the age of 25 weeks (n=4) and 80 weeks (n=7) were infused in situ with contrast agent and harvested for scanning with nano-CT. The spatial distribution of vasa vasorum [number and area/cross-section (mm2)] was compared to aortic luminal cross-sectional area and plaque cross-sectional area in the ascending aorta, aortic arch and descending aorta. Results were complemented with co-localized histology. RESULTS The number and total luminal cross-sectional area of VV showed a significant decrease in the ascending aorta and aortic arch from 25 to 80 weeks but not in the descending aorta. The number and cross-sectional area of VV showed significant local differences depending on whether it was near a fibrotic, and hemorrhaged or calcified plaque in animals at the age of 80 weeks. Area of VV progressively increased along the aorta from least in the ascending aorta<aortic arch<descending aorta in animals at the age of 80 weeks and is inverse in animals aged 25 weeks. CONCLUSION Atherosclerotic lesion type is correlated to the number and cross-sectional area of VV in different aortic segments in apoE-/-/LDL-/- mice. The chronological development of VV along the aorta proceeds distally from the ascending aorta and aortic arch.
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Affiliation(s)
- M Kampschulte
- Department of Radiology, University of Giessen, Germany
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Kampschulte M, Brinkmann A, Stieger P, Sedding DG, Dierkes C, Bohle RM, Ritman EL, Langheinrich A. Quantitative Imaging of Transmural Vasa Vasorum Distribution in Aortas of ApoE-/-/LDL-/- double knockout Mice using Nano-CT. ROFO-FORTSCHR RONTG 2010. [DOI: 10.1055/s-0030-1252835] [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: 10/19/2022]
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Abstract
In this contribution, we extend the theory of symmetry-based pulse sequences of types CN(n) (nu) and RN(n) (nu) in magic-angle-spinning nuclear resonance spectroscopy [M. H. Levitt, in Encyclopedia of Nuclear Magnetic Resonance, edited by D. M. Grant and R. K. Harris (Wiley, Chichester, 2002), Vol. 9]. to the case of rotating the sample simultaneously around two different angles with respect to the external magnetic field (double-rotation). We consider the case of spin-1/2 nuclei in general and the case of half-integer quadrupolar nuclei that are subjected to weak radio frequency pulses operating selectively on the central-transition polarizations. The transformation properties of the homonuclear dipolar interactions and J-couplings under central-transition-selective spin rotations are presented. We show that the pulse sequence R2(2) (1)R2(2) (-1) originally developed for homonuclear dipolar recoupling of half-integer quadrupolar nuclei under magic-angle-spinning conditions [M. Eden, D. Zhou, and J. Yu, Chem. Phys. Lett. 431, 397 (2006)] may be used for the same purpose in the case of double rotation, if the radio frequency pulses are synchronized with the outer rotation of the sample. We apply this sequence, sandwiched by central-transition selective 90 degrees pulses, to excite double-quantum coherences in homonuclear spin systems consisting of (23)Na and (27)Al nuclei.
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Affiliation(s)
- Andreas Brinkmann
- Physical Chemistry/Solid State NMR, Institute for Molecules and Materials, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands.
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Brinkmann A, Steffen P, Pfaff H. [Patient surveys as an element of quality management in outpatient care: development and assessment of a questionnaire]. Gesundheitswesen 2008; 69:585-92. [PMID: 18080929 DOI: 10.1055/s-2007-990307] [Citation(s) in RCA: 5] [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: 10/22/2022]
Abstract
OBJECTIVE The present study was designed to develop and assess a questionnaire measuring all relevant quality dimensions of general practice care from the patients' perspective. Furthermore, the study aimed to evaluate the implementation of a patient survey in outpatient care. METHODS Based on the Kölner Patientenfragebogen (KPF) and by developing some additional new items, we created the new questionnaire KPF-A (Kölner Patientenfragebogen-ambulant) which covers all relevant aspects of outpatient care. The questionnaire was distributed to the patients of 41 GP's and specialists in ambulatory care from different regions of Germany. N=3188 patients were included in the sample. We used these data to assess some selected psychometric characteristics of the KPF-A. Factor analysis was used to examine the underlying factor structure. A qualitative study was conducted to evaluate the implementation of the patient survey. Therefore, all N=41 doctors involved were asked to complete five open questions concerning their experience. RESULTS Most scales of the KPF-A showed good psychometric characteristics in the present study. Factor analysis revealed a two-factors solution for the new items representing the dimensions "professional competence" and "medical equipment". We have not yet been able to find a sound factor solution for those items representing the dimension "Staff and Organisation". The results of the qualitative study revealed a satisfying implementation of the patient survey in daily routine from the doctors' perspective. The length of the questionnaire was criticised by some participants. In the design of the study patients were supposed to fill in the questionnaires after consultation. This turned out to be difficult. We therefore modified the KPF-A so that patients can fill it in either before or after consultation.
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Affiliation(s)
- A Brinkmann
- Abteilung Medizinische Soziologie des Instituts und der Poliklinik für Arbeits- und Sozialmedizin, Medizinische Fakultät der Universität zu Köln, Köln.
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Schumm F, Brinkmann A, Fateh-Moghadam A. Antikörperkontrollierte zytostatische Therapie des malignen Thymoms bei begleitender Myasthenia gravis. Dtsch Med Wochenschr 2008; 109:1244-6. [PMID: 6547902 DOI: 10.1055/s-2008-1069357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
In a 46-year-old female patient with malignant thymoma and concomitant myasthenia gravis relapse with gravitational metastases occurred 6 1/2 years after the first operation. Metastases could be removed surgically only partially and were subsequently irradiated with 50 Gy. After 3 1/2 years renewed metastatic growth occurred. Until then the concomitant myasthenia had been stable during treatment with pyridostigmine and azathioprin and intermittent prednisone; acetylcholine receptor antibody titres had remained largely stable. Combined cytostatic treatment with vincristine, cyclophosphamide, prednisone and doxorubicin or cisplatin led to regression of metastases during the observation period of 1 1/2 years and at the same time to stabilisation of the myasthenia. Acetylcholine receptor antibody titres decreased and this was roughly paralleled by clinical improvement. Whereas there is no obvious correlation of antibodies against acetylcholine-receptor protein and tendency of tumour growth there is good agreement with the course of the accompanying myasthenia.
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Kentgens APM, Bart J, van Bentum PJM, Brinkmann A, van Eck ERH, Gardeniers JGE, Janssen JWG, Knijn P, Vasa S, Verkuijlen MHW. High-resolution liquid- and solid-state nuclear magnetic resonance of nanoliter sample volumes using microcoil detectors. J Chem Phys 2008; 128:052202. [DOI: 10.1063/1.2833560] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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Koehl U, Bochennek K, Esser R, Brinkmann A, Quaritsch R, Becker M, Soerensen J, Bader P, Schwabe D, Klingebiel T, Fischer J, Zimmermann SY. ISHAGE-based single-platform flowcytometric analysis for measurement of absolute viable T cells in fresh or cryopreserved products: CD34/CD133 selected or CD3/CD19 depleted stem cells, DLI and purified CD56+CD3− NK cells. Int J Hematol 2007; 87:98-105. [DOI: 10.1007/s12185-007-0018-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2007] [Revised: 08/27/2007] [Accepted: 09/27/2007] [Indexed: 01/25/2023]
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Brinkmann A, Litvinov VM, Kentgens APM. Environmentally friendly flame retardants. A detailed solid-state NMR study of melamine orthophosphate. Magn Reson Chem 2007; 45 Suppl 1:S231-S246. [PMID: 18157843 DOI: 10.1002/mrc.2159] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We used solid-state NMR spectroscopy to gain detailed information about the proton positions, proximities and the hydrogen-bonding network in the environmentally friendly flame retardant melamine orthophosphate (MP). High-resolution proton one- and two-dimensional solid-state NMR spectra were obtained at high external magnetic field in combination with fast magic angle spinning of the sample. Furthermore, we recorded homo- and heteronuclear correlation spectra of types (15)N–(15)N, (1)H–(13)C, (1)H–(15)N and (1)H–(31)P. In addition, we determined the geometry of the NH and NH(2) groups in MP by (15)N–(1)H heteronuclear recoupling experiments.We were able to completely assign the different isotropic chemical shifts in MP. Furthermore, we could identify the protonation of the melamine and orthophosphate moieties. The experimental results are discussed in connection with the structural model obtained by powder X-ray diffraction together with a combined molecular modeling-Rietveld refinement approach (De Ridder et al. Helv. Chim. Acta 2004; 87: 1894). We show that the geometry of the NH2 groups can only be successfully estimated by solid-state NMR.
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Affiliation(s)
- Andreas Brinkmann
- Physical Chemistry/Solid State NMR, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.
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Yoshida T, Otsuka S, Jones DG, Spencer JL, Binger P, Brinkmann A, Wedemann P. Two-Coordinate Phosphine Complexes of Palladium(0) and Platinum(0). ACTA ACUST UNITED AC 2007. [DOI: 10.1002/9780470132593.ch30] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
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Abstract
The heart of any surgical department is the operation room area. Any disturbances in the daily routine will affect the work flow of the whole hospital. As an example the major complaints of a university surgical department regarding workflow and communication are outlined. To solve these problems a team "OR organization" was established, which started the work based on a new developed OR statute. Within a short period the contentment of the employees as well as the workflow improved. But as a matter of fact, even in the following years of central OR management there is still the need to further stabilize the system and carefully improve the controlling system.
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Affiliation(s)
- F Gebhard
- Universitätsklinikum Ulm, Abteilung für Unfallchirurgie.
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Brinkmann A, Kentgens APM. Proton-Selective17O−1H Distance Measurements in Fast Magic-Angle-Spinning Solid-State NMR Spectroscopy for the Determination of Hydrogen Bond Lengths. J Am Chem Soc 2006; 128:14758-9. [PMID: 17105257 DOI: 10.1021/ja065415k] [Citation(s) in RCA: 188] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a proton-selective method to determine 17O-1H distances in organic, biological, and biomimetic materials by fast magic-angle-spinning solid-state NMR spectroscopy. This method allows the determination of internuclear distances between specific (17O, 1H) spin pairs selectively. It enables the estimation of medium-range 17O...1H distances across hydrogen bonds in the presence of short-range 17O-1H contacts sharing the same 17O site. The method employs the newly developed symmetry-based radiofrequency pulse sequence SR%@mt;sys@%4%@sx@%1%@be@%2%@sxx@%%@mx@% applied to the protons to achieve heteronuclear dipolar recoupling, while simultaneously decoupling the homonuclear proton dipolar interactions. Fast MAS (50 kHz) and high static magnetic fields (18.8 T) achieve the required proton spectral resolution.
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Affiliation(s)
- Andreas Brinkmann
- Physical Chemistry/Solid State NMR, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.
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Abstract
In this contribution we present a comprehensive approach to study hydrogen bonding in biological and biomimetic systems through 17O and 17O-1H solid-state NMR combined with density functional theory calculations of 17O and 1H NMR parameters. We explore the signal enhancement of 17O in L-tyrosine.HCl using repetitive double-frequency swept radio frequency pulses in solid-state NMR. The technique is compatible with high magnetic fields and fast magic-angle spinning of the sample. A maximum enhancement by a factor of 4.3 is obtained in the signal-to-noise ratio of the selectively excited 17O central transition in a powdered sample of 17Oeta-L-tyrosine.HCl at an external field of 14.1 T and a spinning frequency of 25 kHz. As little as 128 transients lead to meaningful 17O spectra of the same sample at an external field of 18.8 T and a spinning frequency of 50 kHz. Furthermore we employed supercycled symmetry-based pulse sequences on the protons to achieve heteronuclear longitudinal two-spin-order (IzSz) recoupling to determine 17O-1H distances. These sequences recouple the heteronuclear dipolar 17O-1H couplings, where dipolar truncation is absent, while decoupling the homonuclear proton dipolar interactions. They can be applied at fast magic-angle-spinning frequencies up and beyond 50 kHz and are very robust with respect to 17O quadrupolar couplings and both 17O and 1H chemical shift anisotropies, which makes them suitable for the use at high external magnetic fields. The method is demonstrated by determining the 17Oeta-1H distance in L-tyrosine.HCl at a spinning frequency of 50 kHz and an external field of 18.8 T.
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Affiliation(s)
- Andreas Brinkmann
- Physical Chemistry/Solid State NMR, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.
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Abstract
We report the construction of a dual-channel microcoil nuclear magnetic resonance probehead allowing magic-angle spinning for mass-limited samples. With coils down to 235 mum inner diameter, this allows high-resolution solid-state NMR spectra to be obtained for amounts of materials of a few nanoliters. This is demonstrated by the carbon-13 spectrum of a tripeptide and a single silk rod, prepared from the silk gland of the Bombyx mori silkworm. Furthermore, the microcoil allows for radio frequency field strengths well beyond current probe technology, aiding in getting the highest possible resolution by efficiently decoupling the observed nuclei from the abundantly present proton nuclei.
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Affiliation(s)
- Hans Janssen
- Department of Physical Chemistry/Solid-State NMR, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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