TY - CONF
A1 - Fricke, F.
A1 - Mahmood, S.
A1 - Hoffmann, J.
A1 - Brandalero, M.
A1 - Liehr, Sascha
A1 - Kern, Simon
A1 - Meyer, Klas
A1 - Kowarik, Stefan
A1 - Westerdicky, S.
A1 - Maiwald, Michael
A1 - Hübner, M.
T1 - Artificial Intelligence for Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy
N2 - Mass Spectrometry (MS) and Nuclear Magnetic Resonance Spectroscopy (NMR) are critical components of every industrial chemical process as they provide information on the concentrations of individual compounds and by-products. These processes are carried out manually and by a specialist, which takes a substantial amount of time and prevents their utilization for real-time closed-loop process control. This paper presents recent advances from two projects that use Artificial Neural Networks (ANNs) to address the challenges of automation and performance-efficient realizations of MS and NMR. In the first part, a complete toolchain has been developed to develop simulated spectra and train ANNs to identify compounds in MS. In the second part, a limited number of experimental NMR spectra have been augmented by simulated spectra to train an ANN with better prediction performance and speed than state-of-theart analysis. These results suggest that, in the context of the digital transformation of the process industry, we are now on the threshold of a possible strongly simplified use of MS and MRS and the accompanying data evaluation by machine-supported procedures, and can utilize both methods much wider for reaction and process monitoring or quality control.
T2 - 2021 Design, Automation & Test in Europe Conference & Exhibition (DATE)
CY - Online meeting
DA - 01.02.2021
KW - Industry 4.0
KW - Cyber-Physical Systems
KW - Artificial Neural Networks
KW - Mass Spectrometry
KW - Nuclear Magnetic Resonance Spectroscopy
PY - 2021
UR - www.date-conference.com
SN - 978-3-9819263-5-4
SP - 615
EP - 620
PB - Research Publishing
AN - OPUS4-52180
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Descalzo López, Ana Belén
A1 - Martínez-Mánez, Ramon
A1 - Sancenón, F.
A1 - Hoffmann, Katrin
A1 - Rurack, Knut
T1 - The Supramolecular Chemistry of Organic-Inorganic Hybrid Materials
N2 - The combination of nanomaterials as solid supports and supramolecular concepts has led to the development of hybrid materials with improved functionalities. These hetero-supramolecular ideas provide a means of bridging the gap between molecular chemistry, materials sciences, and nanotechnology. In recent years, relevant examples have been reported on functional aspects, such as enhanced recognition and sensing by using molecules on preorganized surfaces, the reversible building of nanometer-sized networks and 3D architectures, as well as biomimetic and gated chemistry in hybrid nanomaterials for the development of advanced functional protocols in three-dimensional frameworks. This approach allows the fine-tuning of the properties of nanomaterials and offers new perspectives for the application of supramolecular concepts.
KW - Aggregation
KW - Mesoporous materials
KW - Molecular recognition
KW - Nanoparticles
KW - Sensors
PY - 2006
DO - https://doi.org/10.1002/anie.200600734
SN - 1433-7851
SN - 1521-3773
SN - 0570-0833
VL - 45
IS - 36
SP - 5924
EP - 5948
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-12824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lisec, Jan
A1 - Hoffmann, F.
A1 - Jaeger, C.
A1 - Bhattacharya, A.
A1 - Schmitt, C. A.
T1 - Nontargeted Identification of Tracer Incorporation in High- Resolution Mass Spectrometry
N2 - “Fluxomics” refers to the systematic analysis of metabolic fluxes in a biological system and may uncover novel dynamic properties of metabolism that remain undetected in conventional metabolomic approaches. In labeling experiments, tracer molecules are used to track changes in the isotopologue distribution of metabolites, which allows one to estimate fluxes in the metabolic network. Because unidentified compounds cannot be mapped on pathways, they are often neglected in labeling experiments. However, using recent developments in de novo annotation may allow to harvest the information present in these compounds if they can be identified. Here, we present a novel tool (HiResTEC) to detect tracer incorporation in high-resolution mass spectrometry data sets. The software automatically extracts a comprehensive, nonredundant list of all compounds showing more than 1% tracer incorporation in a nontargeted fashion. We explain and show in an example data set how mass precision and other filter heuristics, calculated on the raw data, can efficiently be used to reduce redundancy and noninformative signals by 95%. Ultimately, this allows to quickly investigate any labeling experiment for a complete set of labeled compounds (here 149) with acceptable false positive rates. We further re-evaluate a published data set from liquid chromatography-electrospray ionization (LC-ESI) to demonstrate broad applicability of our tool and emphasize importance of quality control (QC) tests. HiResTEC is provided as a package in the open source software framework R and is freely available on CRAN.
KW - Fluxomics
KW - R package
KW - Mass-Spectrometry
PY - 2018
DO - https://doi.org/10.1021/acs.analchem.8b00356
VL - 90
IS - 12
SP - 7253
EP - 7260
PB - ACS Publications
AN - OPUS4-45493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martínez, R.
A1 - Sancenón, F.
A1 - Hoffmann, Katrin
A1 - Rurack, Knut
A1 - Descalzo López, Ana Belén
T1 - Materiales híbridos en química analítica
N2 - El desarrollo de receptores sintéticos complejos basados en conceptos de la química supramolecular no garantiza en ocasiones un reconocimiento molecular selectivo. Una alternativa en ciertos aspectos más simple y prometedora es el empleo de materiales híbridos orgánico-inorgánicos preparados mediante la funcionalización de sólidos inorgánicos porosos con receptores sintéticos adecuados. El anclaje de estos sistemas coordinantes a un soporte sólido da lugar a ciertos efectos sinérgicos que no están presentes ni en el material inicial ni en el receptor por separado y que sugieren que estos nuevos materiales híbridos pueden ser empleados en el desarrollo de nuevos sensores y nuevos protocolos de reconocimiento molecular y/o iónico.
The development of synthetic receptors based in supramolecular chemistry concepts will no allow a selective molecular recognition. A more simple, convenient and innovative approach relies on the use of organic-inorganic hybrid materials. These hybrid materials will be prepared by the grafting of certain synthetic receptors onto porous inorganic solids. The grafting of these coordinating systems onto a solid support leads to synergic effects that are hardly achievable with only the synthetic receptors or the solids alone. The presence of these synergic effects suggests that these organic-inorganic hybrid materials will be used for the development of novel sensory systems and novel molecular and/or ionic recognitionprotocols.
KW - Soportes inorgánicos
KW - Receptores sintéticos
KW - Materiales híbridos
KW - Efectos sinérgicos
KW - Química analítica
KW - Inorganic supports
KW - Synthetic receptors
KW - Hybrid materials
KW - Synergic effects
KW - Analytical chemistry
PY - 2007
SN - 1575-3417
VL - 103
IS - 4
SP - 22
EP - 27
PB - Springer
AN - OPUS4-17512
LA - spa
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlögl, Johanna
A1 - Krappe, Alexander R.
A1 - Fürstenwerth, Paul C.
A1 - Brosius, Amelie L.
A1 - Fasting, Carlo
A1 - Hoffmann, Kurt F.
A1 - Resch-Genger, Ute
A1 - Eigler, Siegfried
A1 - Steinhauer, Simon
A1 - Riedel, Sebastian
T1 - Luminescent Perhalofluoro Trityl Radicals
N2 - In this proof-of-concept study, we show that polyfluorinated trityl radicals with the, to this date, highest fluorination grade can be accessed in quantitative yields in a straightforward manner starting from the perfluorinated trityl cation. The trityl skeleton is functionalized with trimethylsilyl halides to yield perhalofluoro trityl cations, which are subsequently reduced using commercial zinc powder. In this way, we prepare three perhalofluoro trityl radicals and analyze the impact of the fluorine ligands on their electro-optical properties, revealing some interesting trends. In comparison to literature-known polychlorinated trityl radicals, the new polyfluorinated derivatives exhibit substantially higher fluorescence quantum yields, longer luminescence lifetimes, and an expanded emission range that extends into the yellow spectral region. They further display enhanced photostability under light irradiation. In radical-stained polystyrene nanoparticles, an additional broad emission band in the red−NIR wavelength region is observed, which is attributed to excimer formation. Finally, the stability of the new radicals is investigated under ambient conditions, showing the slow conversion with atmospheric oxygen yielding the respective peroxides, which are characterized by single-crystal X-ray diffraction. All in all, our study extends the present scope of luminescent trityl radicals, as the functionalization of the perfluorinated cationic precursor unlocks the path toward a vast variety of polyfluorinated trityl radicals.
KW - Dye
KW - Fluorescence
KW - Radical
KW - Synthesis
KW - Mechanism
KW - Signal enhancement
KW - Nano
KW - Particle
KW - Characterization
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Polarity
KW - Polymer
KW - Solvatchromism
KW - Excimer
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647973
DO - https://doi.org/10.1021/jacs.5c16418
SN - 0002-7863
VL - 147
IS - 46
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-64797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Descalzo López, Ana Belén
A1 - Martínez-Mánez, Ramon
A1 - Sancenón, F.
A1 - Hoffmann, Katrin
A1 - Rurack, Knut
T1 - Die supramolekulare Chemie organisch-anorganischer Hybrid-Nanomaterialien
N2 - Die Entwicklung von Hybridmaterialien mit stark verbesserten Funktionen gelingt durch die Kombination geeigneter Nanomaterialien als Träger mit Motiven aus der supramolekularen Chemie. Diese hetero-supramolekularen Konzepte bieten vielfältige Möglichkeiten, die Lücken zwischen der Molekülchemie, Materialwissenschaften und Nanotechnologie zu schließen. Im Hinblick auf funktionelle Aspekte wurden in jüngster Zeit wichtige Fortschritte erzielt, z. B. verbesserte Erkennungs- und Sensoreigenschaften durch die Anordnung von Molekülen auf vororganisierten Oberflächen, der reversible Aufbau von nanometergroßen Netzwerken und dreidimensionalen Strukturen oder biomimetische und gesteuerte chemische Prozesse in Hybrid-Nanomaterialien, die als Grundlage für hoch spezialisierte Protokolle in dreidimensionalen Gerüststrukturen dienen können. Diese Ansätze ermöglichen eine Feinabstimmung der Eigenschaften von Nanomaterialien und eröffnen neue Perspektiven für die Anwendung supramolekularer Konzepte.
KW - Supramolekulare Chemie
KW - Anorganisch-organische Hybridmaterialien
KW - Sensorik
KW - Molekulare Maschinen
KW - Aggregation
KW - Mesoporöse Materialien
KW - Molekulare Erkennung
KW - Nanopartikel
KW - Sensoren
PY - 2006
DO - https://doi.org/10.1002/ange.200600734
SN - 0044-8249
SN - 0932-2140
SN - 1521-3757
VL - 118
IS - 36
SP - 6068
EP - 6093
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-12821
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Descalzo López, Ana Belén
A1 - Hoffmann, Katrin
A1 - Rurack, Knut
A1 - Martínez-Mánez, Ramon
A1 - Sancenón, F.
T1 - Hybridmaterialien in der analytischen Chemie
KW - Analytische Chemie
KW - Hybridmaterialien
KW - Sensorik
KW - Fluoreszenz
KW - Absorption
KW - Mesoporöse Silicate
KW - Goldnanopartikel
KW - Quantenpunkte
PY - 2007
SN - 1439-9598
SN - 1521-3854
VL - 55
IS - 02
SP - 124
EP - 129
PB - Wiley-VCH Verl.
CY - Weinheim
AN - OPUS4-16080
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Bremser, Wolfram
A1 - Pfeifer, Dietmar
A1 - Spieles, Monika
A1 - Hoffmann, Angelika
A1 - DeRose, P.C.
A1 - Zwinkels, J. C.
A1 - Gauthier, F.
A1 - Ebert, B.
A1 - Taubert, R.D.
A1 - Voigt, J.
A1 - Hollandt, J.
A1 - Macdonald, R.
T1 - State-of-the art comparability of corrected emission spectra. 2. Field laboratory assessment of calibration performance using spectral fluorescence standards
N2 - In the second part of this two-part series on the state-of-the-art comparability of corrected emission spectra, we have extended this assessment to the broader community of fluorescence spectroscopists by involving 12 field laboratories that were randomly selected on the basis of their fluorescence measuring equipment. These laboratories performed a reference material (RM)-based fluorometer calibration with commercially available spectral fluorescence standards following a standard operating procedure that involved routine measurement conditions and the data evaluation software LINKCORR developed and provided by the Federal Institute for Materials Research and Testing (BAM). This instrument-specific emission correction curve was subsequently used for the determination of the corrected emission spectra of three test dyes, X, QS, and Y, revealing an average accuracy of 6.8% for the corrected emission spectra. This compares well with the relative standard uncertainties of 4.2% for physical standard-based spectral corrections demonstrated in the first part of this study (previous paper in this issue) involving an international group of four expert laboratories. The excellent comparability of the measurements of the field laboratories also demonstrates the effectiveness of RM-based correction procedures.
KW - Fluorescence
KW - Photoluminescence
KW - Dye
KW - Uncertainty
KW - Method comparison
KW - Standard
KW - Spectral correction
KW - Spectral fluorescence standard
PY - 2012
DO - https://doi.org/10.1021/ac203451g
SN - 0003-2700
SN - 1520-6882
VL - 84
IS - 9
SP - 3899
EP - 3907
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-27081
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hörmann, Anja F.
A1 - Simon, Miriam
A1 - Brückner, Christoph
A1 - Rogers, Sarah E.
A1 - Porcar, Lionel
A1 - Hoffmann, Ingo
A1 - Gradzielski, Michael
T1 - Line tension controls the spontaneous formation of vesicles
N2 - Mixtures of the zwitterionic surfactant TDMAO and the anionic surfactant LiPFOS spontaneously self-assemble into well defined vesicles. The size of these vesicles is determined by the ratio of bending rigidity and line tension. By partially charging TDMAO, and thereby moving more to a catanionic system, the size of these vesicles can be controlled. Using stopped flow small angle neutron scattering we monitor the kinetics of vesicle formation and obtain their final size. Neutron spin echo spectroscopy allows for an independent measurement of the vesicle’s bending rigidity. Combining this bending rigidity with the radius of newly formed vesicles, which is determined by the ratio of bending rigidity and line tension, we can determine the line tension. We find that it is the line tension that controls the trend in size of the vesicles. In summary, this means that here one has a surfactant mixture that delivers well-defined vesicles, whose size is controlled by the electrostatic interactions of the head groups.
KW - Self-assembly
KW - Small unilamellar vesicles
KW - Small-angle neutron scattering
KW - Line tension
KW - Neutron spin-echo spectroscopy
KW - Stopped-flow
KW - Bending rigidity
KW - Surfactant mixture
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646964
DO - https://doi.org/10.1039/D5SM00600G
SN - 1744-683X
VL - 21
IS - 43
SP - 8360
EP - 8367
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64696
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nirmalananthan-Budau, Nithiya
A1 - Behnke, Thomas
A1 - Hoffmann, Katrin
A1 - Kage, Daniel
A1 - Gers-Panther, Charlotte F.
A1 - Frank, Walter
A1 - Müller, Thomas J. J.
A1 - Resch-Genger, Ute
T1 - Crystallization and Aggregation-Induced Emission in a Series of Pyrrolidinylvinylquinoxaline Derivatives
N2 - Aggregation-induced emission (AIE) has been meanwhile observed for many dye classes and particularly for fluorophores containing propeller-like groups. Herein, we report on the AIE characteristics of a series of four hydrophobic pyrrolidinylvinylquinoxaline (PVQ) derivatives with phenyl, pyrrolyl, indolyl, and methoxythienyl substituents used to systematically vary the torsion angle between this substituent at the quinoxaline C2 position and the planar PVQ moiety. These molecules, which are accessible via four- or five-component one-pot syntheses, were spectroscopically studied in organic solvents and solvent−water mixtures, as dye aggregates, solids, and entrapped in polystyrene particles (PSP). Steady-state and time-resolved fluorescence measurements revealed a strong fluorescence enhancement for all dyes in ethanol−water mixtures of high water content, accompanying the formation of dye aggregates with sizes of a few hundred nm, overcoming polarity and H-bonding-induced fluorescence quenching of the chargetransfer-type emission of these PVQ dyes. The size and shape of these dye aggregates and the size of the AIE effect are controlled by the water content and the substituent-dependent torsion angle that influences the nucleation process and the packing of the molecules during aggregation. Staining of 1 μm-sized carboxy-functionalized PSP with the PVQ dyes resulted also in a considerable increase in the fluorescence quantum yield and lifetime, reflecting the combined influence of the restricted molecular motion and the reduced polarity of the dye microenvironment.
KW - Spectroscopy
KW - AIE
KW - Aggregates
KW - Nanoparticle
PY - 2018
DO - https://doi.org/10.1021/acs.jpcc.8b01425
SN - 1932-7447
N1 - Geburtsname von Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. - Birth name of Nirmalananthan-Budau, Nithiya: Nirmalananthan, N.
VL - 122
IS - 20
SP - 11119
EP - 11127
PB - ACS Publications
AN - OPUS4-45176
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hoffmann, Katrin
A1 - Resch-Genger, Ute
A1 - Marlow, F.
ED - Laeri, F.
T1 - Photosensitive Optical Properties of Zeolitic Nanocomposites
PY - 2003
SN - 3-527-30501-7
SP - 501
EP - 520
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-2714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Engel, A.
A1 - Ottermann, C.
A1 - Klahn, J.
A1 - Enseling, D.
A1 - Korb, T.
A1 - Resch-Genger, Ute
A1 - Hoffmann, Katrin
A1 - Schweizer, S.
A1 - Selling, J.
A1 - Kynast, U.
A1 - Koberling, F.
A1 - Rupertus, V.
T1 - Fluorescence reference materials used for optical and biophotonic applications
N2 - Fluorescence techniques are known for their high sensitivity and are widely used as analytical tools and detection methods for product and process control, material sciences, environmental and bio-technical analysis, molecular genetics, cell biology, medical diagnostics, and drug screening. According to DIN/ISO 17025 certified standards are used for fluorescence diagnostics having the drawback of giving relative values for fluorescence intensities only. Therefore reference materials for a quantitative characterization have to be related directly to the materials under investigation. In order to evaluate these figures it is necessary to calculate absolute numbers like absorption/excitation cross sections and quantum yield. This can be done for different types of dopands in different materials like glass, glass ceramics, crystals or nano crystalline material embedded in polymer matrices. Based on the optical spectroscopy data we will discuss options for characteristic doped glasses and glass ceramics with respect to scattering and absorption regime. It has shown recently for YAG:Ce glass ceramics that for a proper determination of the quantum efficiency in these highly scattering media a reference material with similar scattering and fluorescent properties is required. This may be performed using the emission decay measurement diagnostics, where the decay time is below 100 ns. In this paper we present first results of these aspects using well performing LUMOGEN RED organic pigments for a comparison of mainly transparent glass with glass ceramics doped with various amounts of dopands e.g. ions of raw earth elements and transition metals. The LUMOGEN red is embedded in silica and polyurethane matrices. Characterisations on wavelength accuracy and lifetime for different environmental conditions (temperature, UV irradiation) have been performed. Moreover intensity patterns and results for homogeneity, isotropy, photo and thermal stability will be discussed. In a next step we will show the transfer of the characterisation methods to inorganic fluophores (YAG:Ce) in silicon. Fluorescence (steady state, decay time) and absorption (remission, absorption) spectroscopy working in different temperature regimes (10 - 350 K) are employed diagnostic methods in order to get a microscopic view of the relevant physical processes and to prove the correctness of the obtained data. The work is funded by BMBF under project number 13N8849.
KW - Fluorescence
KW - Reference material
KW - Glass
KW - Glass ceramic
KW - Phosphor
KW - Doped glass
KW - Glass ceramics
PY - 2007
SN - 0-8194-6247-0
DO - https://doi.org/10.1117/12.728144
SN - 1605-7422
VL - 6628
SP - 662815-1 - 662815-9
AN - OPUS4-16729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Bremser, Wolfram
A1 - Pfeifer, Dietmar
A1 - Spieles, Monika
A1 - Hoffmann, Angelika
A1 - DeRose, P.C.
A1 - Zwinkels, J. C.
A1 - Gauthier, F.
A1 - Ebert, B.
A1 - Taubert, D.
A1 - Monte, C.
A1 - Voigt, J.
A1 - Hollandt, J.
A1 - Macdonald, R.
T1 - State-of-the art comparability of corrected emission spectra. 1. spectral correction with physical transfer standards and spectral fluorescence standards by expert laboratories
N2 - The development of fluorescence applications in the life and material sciences has proceeded largely without sufficient concern for the measurement uncertainties related to the characterization of fluorescence instruments. In this first part of a two-part series on the state-of-the-art comparability of corrected emission spectra, four National Metrology Institutes active in high-precision steady-state fluorometry performed a first comparison of fluorescence measurement capabilities by evaluating physical transfer standard (PTS)-based and reference material (RM)-based calibration methods. To identify achievable comparability and sources of error in instrument calibration, the emission spectra of three test dyes in the wavelength region from 300 to 770 nm were corrected and compared using both calibration methods. The results, obtained for typical spectrofluorometric (0°/90° transmitting) and colorimetric (45°/0° front-face) measurement geometries, demonstrated a comparability of corrected emission spectra within a relative standard uncertainty of 4.2% for PTS- and 2.4% for RM-based spectral correction when measurements and calibrations were performed under identical conditions. Moreover, the emission spectra of RMs F001 to F005, certified by BAM, Federal Institute for Materials Research and Testing, were confirmed. These RMs were subsequently used for the assessment of the comparability of RM-based corrected emission spectra of field laboratories using common commercial spectrofluorometers and routine measurement conditions in part 2 of this series (subsequent paper in this issue).
KW - Fluorescence
KW - Photoluminescence
KW - Dye
KW - Uncertainty
KW - Method comparison
KW - Standard
KW - Spectral correction
KW - Spectral fluorescence standard
PY - 2012
DO - https://doi.org/10.1021/ac2034503
SN - 0003-2700
SN - 1520-6882
VL - 84
IS - 9
SP - 3889
EP - 3898
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-25838
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tamschick, S.
A1 - Rozenblut-Kościsty, B.
A1 - Ogielska, M.
A1 - Lehmann, Andreas
A1 - Lymberakis, P.
A1 - Hoffmann, F.
A1 - Lutz, I.
A1 - Kloas, W.
A1 - Stöck, M.
T1 - Sex reversal assessments reveal different vulnerability to endocrine disruption between deeply diverged anuran lineages
N2 - Multiple anthropogenic stressors cause worldwide amphibian declines. Among several poorly investigated causes is global pollution of aquatic ecosystems with endocrine disrupting compounds (EDCs). These substances interfere with the endocrine system and can affect the sexual development of vertebrates including amphibians. We test the susceptibility to an environmentally relevant contraceptive, the artificial estrogen 17α-ethinylestradiol (EE2), simultaneously in three deeply divergent systematic anuran families, a model-species, Xenopus laevis (Pipidae), and two non-models, Hyla arborea (Hylidae) and Bufo viridis (Bufonidae). Our new approach combines synchronized tadpole exposure to three EE2-concentrations (50, 500, 5,000 ng/L) in a flow-through-system and pioneers genetic and histological sexing of metamorphs in non-model anurans for EDC-studies. This novel methodology reveals striking quantitative differences in genetic-male-to-phenotypic-female sex reversal in non-model vs. model species. Our findings qualify molecular sexing in EDC-analyses as requirement to identify sex reversals and state-of-the-art approaches as mandatory to detect speciesspecific vulnerabilities to EDCs in amphibians.
KW - Endocrine disruption
KW - 17α-ethinylestradiol (EE2)
KW - Mass spectrometry
KW - Sex reversal
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357797
DO - https://doi.org/10.1038/srep23825
SN - 2045-2322
VL - 6
SP - Article No. 23825, 1
EP - 8
PB - Nature publishing group
AN - OPUS4-35779
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ferreira da Silva, F.
A1 - do N. Varella, M. T.
A1 - Jones, N. C.
A1 - Vrönning Hoffmann, S.
A1 - Denifl, S.
A1 - Bald, Ilko
A1 - Kopyra, J.
T1 - Electron-Induced Reactions in 3-Bromopyruvic Acid
N2 - 3-Bromopyruvic acid (3BP) is a potential anticancer drug, the action of which on cellular metabolism is not yet entirely clear. The presence of a bromine atom suggests that it is also reactive towards low-energy electrons, which are produced in large quantities during tumour Radiation therapy. Detailed knowledge of the interaction of 3BP with secondary electrons is a prerequisite to gain a complete picture of the effects of 3BP in different forms of Cancer therapy. Herein, dissociative electron attachment (DEA) to 3BP in the gas phase has been studied both experimentally by using a crossed-beam setup and theoretically through scattering and quantum chemical calculations. These results are complemented by a vacuum ultraviolet absorption spectrum.
The main fragmentation channel is the formation of Br@ close to 0 eV and within several resonant features at 1.9 and 3–8 eV. At low electron energies, Br@ formation proceeds through s* and p* shape resonances, and at higher energies through core-excited resonances. It is found that the electron-capture cross-section is clearly increased compared with that of non-brominated pyruvic acid, but, at the same time, fragmentation reactions through DEA are significantly altered as well. The 3BP transient negative ion is subject to a lower number of fragmentation reactions than those of pyruvic acid, which indicates that 3BP could indeed act by modifying the electron-transport chains within oxidative phosphorylation. It could also act as a radio-sensitiser.
KW - Density functional calculations
KW - Dissociative electron attachment
KW - Drug discovery
KW - Gas-phase reactions
KW - Sensitizers
PY - 2019
DO - https://doi.org/10.1002/chem.201806132
SN - 0947-6539
VL - 25
IS - 21
SP - 5498
EP - 5506
PB - WILEY-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-48003
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruna, F. G.
A1 - Prokop, M.
A1 - Bystron, T.
A1 - Loukrakpam, R.
A1 - Melke, J.
A1 - Lobo, C. M. S.
A1 - Fink, M.
A1 - Zhu, M.
A1 - Voloshina, E.
A1 - Kutter, M.
A1 - Hoffmann, H.
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, B.
A1 - Bouzek, K.
A1 - Paulus, B.
A1 - Roth, C.
T1 - Following adsorbed intermediates on a platinum gas diffusion electrode in H3PO3‑containing electrolytes using in situ X‑ray absorption spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalyst with H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - Δμ XANES
KW - H3PO3
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - ACS
CY - Washington, DC
AN - OPUS4-55815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gomes, Bruna F.
A1 - Prokop, Martin
A1 - Bystron, Tomas
A1 - Loukrakpam, Rameshwori
A1 - Melke, Julia
A1 - Lobo, Carlos M. S.
A1 - Fink, Michael
A1 - Zhu, Mengshu
A1 - Voloshina, Elena
A1 - Kutter, Maximilian
A1 - Hoffmann, Hendrik
A1 - Yusenko, Kirill V.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, Bettina
A1 - Bouzek, Karel
A1 - Paulus, Beate
A1 - Roth, Christina
T1 - Following Adsorbed Intermediates on a Platinum Gas Diffusion Electrode in H3PO3-Containing Electrolytes Using In Situ X-ray Absorption Spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalystwith H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate Proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - H3PO3,
KW - Δμ XANES
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - American Chemical Society (ACS)
AN - OPUS4-64733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bui, M.
A1 - Hoffmann, K. F.
A1 - Braun, T.
A1 - Riedel, S.
A1 - Heinekamp, Christian
A1 - Scheurell, K.
A1 - Scholz, G.
A1 - Stawski, Tomasz
A1 - Emmerling, Franziska
T1 - An Amorphous Teflate Doped Aluminium Chlorofluoride:
A Solid Lewis-Superacid for the Dehydrofluorination of
Fluoroalkanes
N2 - Ananion-dopedaluminiumchlorofluoride AlCl0.1F2.8(OTeF5)0.1(ACF-teflate) was synthesized.The material contains pentafluor-oorthotellurate(teflate)groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR-IR spectra of adsorbed CD3CN reveal a blue-shift of the adsorption band by73 cm-1, which is larger than the shift for SbF5. Remarkably,ACF-teflate catalyzes dehydrofluorination reactions of mono-fluoroalkanes to yield olefins in C6D6. In these cases,no Friedel-Crafts products were formed.
KW - Aluminium fluorides
KW - Aluminium teflates
KW - C-F bond activation
KW - Lewis superacids
KW - Silanes
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572290
DO - https://doi.org/10.1002/cctc.202300350
SN - 1867-3880
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-57229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grunert, B.
A1 - Saatz, Jessica
A1 - Hoffmann, Katrin
A1 - Appler, F.
A1 - Lubjuhn, Dominik
A1 - Jakubowski, Norbert
A1 - Resch-Genger, Ute
A1 - Emmerling, Franziska
A1 - Briel, A.
T1 - Multifunctional rare-earth element nanocrystals for cell labeling and multimodal imaging
N2 - In this work, we describe a simple solvothermal route for the synthesis of Eu3+-doped gadolinium orthovanadate nanocrystals (Eu:GdVO4−PAA) functionalized with poly(acrylic)acid (PAA), that are applicable as cell labeling probes for multimodal cellular imaging. The Eu3+ doping of the vanadate matrix provides optical functionality, due to red photoluminescence after illumination with UV light. The Gd3+ ions of the nanocrystals reduce the T1 relaxation time of surrounding water protons, allowing these nanocrystals to act as a positive MRI contrast agent with a r1 relaxivity of 1.97 mM−1 s−1. Low background levels of Eu3+, Gd3+, and V5+ in biological systems make them an excellent label for elemental microscopy by Laser Ablation (LA)-ICP-MS. Synthesis resulted in polycrystalline nanocrystals with a hydrodynamic diameter of 55 nm and a crystal size of 36.7 nm, which were further characterized by X-ray diffraction (XRD), photoluminescence spectroscopy (PL) and transmission electron microscopy (TEM). The multifunctional nanocrystals were subsequently used for intracellular labeling of both human adipose-derived stem cells (MSCs) and A549 (adenocarcinomic human alveolar basal epithelial) cells.
KW - Bioimaging
KW - Nanoparticle
KW - Multimodal
KW - Lanthanide
PY - 2018
DO - https://doi.org/10.1021/acsbiomaterials.8b00495
SN - 2373-9878
VL - 4
IS - 10
SP - 3578
EP - 3587
PB - ACS Publications
CY - Washington, USA
AN - OPUS4-46244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, H
A1 - Paulisch, M C
A1 - Gebhard, M
A1 - Osiewacz, J
A1 - Kutter, M
A1 - Hilger, A
A1 - Arlt, T
A1 - Kardjilov, N
A1 - Ellendorff, B
A1 - Beckmann, F
A1 - Markötter, Henning
A1 - Luik, M
A1 - Turek, T
A1 - Manke, I
A1 - Roth, C
T1 - Development of a Modular Operando Cell for X-ray Imaging of Strongly Absorbing Silver-Based Gas Diffusion Electrodes
N2 - Metal-based gas diffusion electrodes are utilized in chlor-alkali electrolysis or electrochemical reduction of carbon dioxide, allowing the reaction to proceed at high current densities. In contrast to planar electrodes and predominantly 2D designs, the industrially required high current densities can be achieved by intense contact between the gas and liquid phase with the catalytically active surfaces. An essential asset for the knowledge-based design of tailored electrodes is therefore in-depth information on electrolyte distribution and intrusion into the electrode’s porous structure. Lab-based and synchrotron radiography allow for monitoring this process operando. Herein, we describe the development of a cell design that can be modularly adapted and successfully used to monitor both the oxygen reduction reaction and the electrochemical reduction of CO2 as exemplary and currently very relevant examples of gas-liquid reactions by only minor modifications to the cell set-up. With the reported cell design, we were able to observe the electrolyte distribution within the gas diffusion electrode during cell operation in realistic
conditions.
KW - X-Ray imaging
KW - Gas diffusion electrodes
KW - Operando cell
PY - 2022
DO - https://doi.org/10.1149/1945-7111/ac6220
VL - 169
IS - 4
SP - 044508
PB - IOP science
AN - OPUS4-55027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Appelhans, Dietmar
A1 - Oertel, U.
A1 - Mazzeo, R.
A1 - Komber, H.
A1 - Hoffmann, J.
A1 - Weidner, Steffen
A1 - Brutschy, B.
A1 - Voit, B.
A1 - Ottaviani, M.F.
T1 - Dense-shell glycodendrimers: UV/Vis and electron paramagnetic resonance study of metal ion complexation
N2 - The development of dendritic metal ion carrier systems for use in a biological environment is a challenging task as the carrier system must possess multiple features (e.g. a protective shell for metal decomplexation, targeting functions, metal-intradendrimer complexes, etc.) to substitute for the function of metal proteins in processes such as copper metabolism. Thus, Cu(II) complexation by a series of poly(propyleneimine) glycodendrimers ranging up to the fifth generation that have either a dense maltose or maltotriose shell was investigated by UV/Vis spectroscopy and electron paramagnetic resonance (EPR). As a necessary step towards potential biological application, we elucidated the complexation capacity, location of the Cu(II)-dendrimer complexes and the Cu(II) coordination sphere in the dendritic environment. A generation-dependent Cu(II) complexation was found. Furthermore, analysis of the EPR spectra revealed that internal and external Cu(II) coordination and the symmetry (axial and rhombic) of the generated complexes depend on the oligosaccharide shell, dendrimer generation and the relative concentrations of Cu(II) and the dendrimers. Both axial and rhombic symmetries are generation dependent, but also distort with increasing generation number. External coordination of Cu(II) is supported by sugar groups and water molecules. Finally, a third-generation dendrimer with a maltose shell was used to explore the general complexation behaviour of the dendritic poly(propyleneimine) scaffold towards different metal ions [Cu(II), Ag(I), VO(IV), Ni(II), Eu(III) and UO2(VI)].
KW - Glycodendrimers
KW - Metal ion complexation
KW - Metal ion-intradendrimer complexes
KW - Electron paramagnetic resonance study
PY - 2010
DO - https://doi.org/10.1098/rspa.2009.0107
SN - 1364-5021
SN - 0962-8444
SN - 0080-4630
SN - 0950-1207
SN - 1471-2946
VL - 466
SP - 1489
EP - 1513
CY - London, UK
AN - OPUS4-21622
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -