32 results on '"Seim C"'
Search Results
2. Nanoscale Imaging Using Coherent and Incoherent Laboratory Based Soft X-Ray Sources
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Stiel, H., Dehlinger, A., Janulewicz, K.A., Jung, R., Legall, H., Pratsch, C., Seim, C., Tümmler, J., Rocca, Jorge, editor, Menoni, Carmen, editor, and Marconi, Mario, editor
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- 2016
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3. Interconnectivity Explains High Canalicular Network Robustness between Neighboring Osteocyte Lacunae in Human Bone
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Bortel, E., Liam Grover, Neil Eisenstein, Seim, C., Suhonen, H., Pacureanu, A., Westenberger, P., Raum, K., Langer, M., Peyrin, F., owen addison, Bernhard Hesse, University of Helsinki, Department of Physics, Xploraytion [Berlin], University of Birmingham [Birmingham], Technical University Berlin, Helsingin yliopisto = Helsingfors universitet = University of Helsinki, European Synchroton Radiation Facility [Grenoble] (ESRF), Thermo Fisher Scientific Inc., Charité - UniversitätsMedizin = Charité - University Hospital [Berlin], Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Translational Innovation in Medicine and Complexity / Recherche Translationnelle et Innovation en Médecine et Complexité - UMR 5525 (TIMC ), VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), King‘s College London, and Langer, Max
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[SDV.MHEP.AHA] Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO] ,ARCHITECTURE ,canalicular network ,[SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging ,osteocyte lacunar networks ,[SPI.MECA.BIOM]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph] ,FLUID-FLOW ,digestive system ,bone mineral homeostasis ,114 Physical sciences ,[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging ,540 Chemie und zugeordnete Wissenschaften ,TISSUE ,[SPI.MECA.BIOM] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph] ,DENSITY ,ddc:540 ,[SDV.MHEP.AHA]Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO] ,MORPHOLOGY ,synchrotron nano computed tomography ,PERMEABILITY - Abstract
International audience; Osteocytes are the most frequent bone cells connected with each other through cell processes within tiny tubular-shaped canaliculi. The so-called osteocyte lacunar-canalicular network (LCN) plays a crucial role in bone remodeling and mineral homeostasis. Given the critical nature of these functions, it is herein hypothesized that the LCN must be structurally “overengineered” to provide network resilience. This hypothesis is tested by characterizing canalicular networks in human bone at the fundamental “building-block” level of LCN formed by two adjacent osteocytes. As the hierarchical micro- and macroscale structure of bone is influenced by anatomical location, subjected loads, and growth rate, three distinct tissue types are studied. These include femur, jaw, and heterotopic ossification (HO), a rapidly forming mineralized tissue found in soft tissue compartments following severe trauma. It is found that the LCNs at the fundamental level are composed of hundreds of canalicular segments but of only few separated groups of linked canaliculi (canalicular clusters), resulting in a strongly pronounced interconnectivity. Fluid permeability simulations on intact and artificially altered LCN suggest that the function of the LCN is not only to optimize rapid and efficient access to bone mineral, but also to maintain high permeability when inevitable local interruption of canaliculi occurs.
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- 2022
4. Nanoscale Imaging Using Coherent and Incoherent Laboratory Based Soft X-Ray Sources
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Stiel, H., primary, Dehlinger, A., additional, Janulewicz, K.A., additional, Jung, R., additional, Legall, H., additional, Pratsch, C., additional, Seim, C., additional, and Tümmler, J., additional
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- 2015
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5. Seismic Retrofitting Highway Truss Bridges
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SEIM, C, primary, YEN, P, additional, and OCONNOR, J, additional
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- 2005
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6. Soft x-ray nanoscale imaging using highly brilliant laboratory sources and new detector concepts
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Stiel, H., additional, Braenzel, J., additional, Dehlinger, A., additional, Jung, R., additional, Luebcke, A., additional, Regehly, M., additional, Ritter, S., additional, Tuemmler, J., additional, Schnuerer, M., additional, and Seim, C., additional
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- 2017
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7. Soft X-ray nanoscale imaging using highly brilliant laboratory sources and new detector concepts.
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Stiel, H., Braenzel, J., Dehlinger, A., Jung, R., Luebcke, A., Regehly, M., Ritter, S., Tuemmler, J., Schnuerer, M., and Seim, C.
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- 2017
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8. Skid Resistance of Epoxy Asphalt Pavements On California Toll Bridges
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Seim, C, primary
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9. Old traces, read anew – ‘The Reading Hermit’ painting in the light of X-ray fluorescence
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Seim, C., primary, Laurenze-Landsberg, C., additional, Schröder-Smeibidl, B., additional, Mantouvalou, I., additional, de Boer, C., additional, and Kanngießer, B., additional
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- 2014
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10. A compact laboratory transmission X-ray microscope for the water window
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Legall, H., Stiel, H., Blobel, G., Seim, C., Baumann, J., Yulin, S., Esser, D., Hoefer, M., Wiesemann, U., Wirtz, M., Schneider, G., Rehbein, S., Hertz, Hans M., Legall, H., Stiel, H., Blobel, G., Seim, C., Baumann, J., Yulin, S., Esser, D., Hoefer, M., Wiesemann, U., Wirtz, M., Schneider, G., Rehbein, S., and Hertz, Hans M.
- Abstract
In the water window (2.2-4.4 nm) the attenuation of radiation in water is significantly smaller than in organic material. Therefore, intact biological specimen (e.g. cells) can be investigated in their natural environment. In order to make this technique accessible to users in a laboratory environment a Full-Field Laboratory Transmission X-ray Microscope (L-TXM) has been developed. The L-TXM is operated with a nitrogen laser plasma source employing an InnoSlab high power laser system for plasma generation. For microscopy the Ly α emission of highly ionized nitrogen at 2.48 nm is used. A laser plasma brightness of 5 × 1011 photons/(s × sr × μm2 in line at 2.48 nm) at a laser power of 70 W is demonstrated. In combination with a state-of-the-art Cr/V multilayer condenser mirror the sample is illuminated with 106 photons/(μm2 × s). Using objective zone plates 35-40 nm lines can be resolved with exposure times < 60 s. The exposure time can be further reduced to 20 s by the use of new multilayer condenser optics and operating the laser at its full power of 130 W. These exposure times enable cryo tomography in a laboratory environment., QC 20140205
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- 2013
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11. Compact X-ray microscope for the water window based on a high brightness laser plasma source
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Legall, H., Blobel, G., Stiel, H., Sandner, W., Seim, C., Takman, Per, Martz, Dale H., Selin, Mårten, Vogt, Ulrich, Hertz, Hans M., Esser, D., Sipma, H., Luttmann, J., Höfffer, M., Hoffmann, H. D., Yulin, S., Feigl, T., Rehbein, S., Guttmann, P., Schneider, G., Wiesemann, U., Wirtz, M., Diete, W., Legall, H., Blobel, G., Stiel, H., Sandner, W., Seim, C., Takman, Per, Martz, Dale H., Selin, Mårten, Vogt, Ulrich, Hertz, Hans M., Esser, D., Sipma, H., Luttmann, J., Höfffer, M., Hoffmann, H. D., Yulin, S., Feigl, T., Rehbein, S., Guttmann, P., Schneider, G., Wiesemann, U., Wirtz, M., and Diete, W.
- Abstract
We present a laser plasma based x-ray microscope for the water window employing a high-average power laser system for plasma generation. At 90 W laser power a brightness of 7.4 x 10(11) photons/(s x sr x mu m(2)) was measured for the nitrogen Ly alpha line emission at 2.478 nm. Using a multilayer condenser mirror with 0.3 % reflectivity 10(6) photons/(mu m(2) x s) were obtained in the object plane. Microscopy performed at a laser power of 60 W resolves 40 nm lines with an exposure time of 60 s. The exposure time can be further reduced to 20 s by the use of new multilayer condenser optics and operating the laser at its full power of 130 W., QC 20120831
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- 2012
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12. High average brightness water window source for short-exposure cryomicroscopy
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Martz, Dale H., Selin, Mårten, von Hofsten, Olov, Fogelqvist, Emelie, Holmberg, Anders, Vogt, Ulrich, Legall, H., Blobel, G., Seim, C., Stiel, H., Hertz, Hans M., Martz, Dale H., Selin, Mårten, von Hofsten, Olov, Fogelqvist, Emelie, Holmberg, Anders, Vogt, Ulrich, Legall, H., Blobel, G., Seim, C., Stiel, H., and Hertz, Hans M.
- Abstract
Laboratory water window cryomicroscopy has recently demonstrated similar image quality as synchrotron-based microscopy but still with much longer exposure times, prohibiting the spread to a wider scientific community. Here we demonstrate high-resolution laboratory water window imaging of cryofrozen cells with 10 s range exposure times. The major improvement is the operation of a lambda = 2.48 nm, 2 kHz liquid nitrogen jet laser plasma source with high spatial and temporal stability at high average brightness >1.5 x 10(12) ph/(s x sr x mu m(2) x line), i.e., close to that of early synchrotrons. Thus, this source enables not only biological x-ray microscopy in the home laboratory but potentially other applications previously only accessible at synchrotron facilities., QC 20121207
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- 2012
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13. A compact Laboratory Transmission X-ray Microscope for the water window
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Legall, H, primary, Stiel, H, additional, Blobel, G, additional, Seim, C, additional, Baumann, J, additional, Yulin, S, additional, Esser, D, additional, Hoefer, M, additional, Wiesemann, U, additional, Wirtz, M, additional, Schneider, G, additional, Rehbein, S, additional, and Hertz, H M, additional
- Published
- 2013
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14. High average brightness water window source for short-exposure cryomicroscopy
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Martz, D. H., primary, Selin, M., additional, von Hofsten, O., additional, Fogelqvist, E., additional, Holmberg, A., additional, Vogt, U., additional, Legall, H., additional, Blobel, G., additional, Seim, C., additional, Stiel, H., additional, and Hertz, H. M., additional
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- 2012
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15. Compact x-ray microscope for the water window based on a high brightness laser plasma source
- Author
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Legall, H., primary, Blobel, G., additional, Stiel, H., additional, Sandner, W., additional, Seim, C., additional, Takman, P., additional, Martz, D. H., additional, Selin, M., additional, Vogt, U., additional, Hertz, H. M., additional, Esser, D., additional, Sipma, H., additional, Luttmann, J., additional, Höfer, M., additional, Hoffmann, H. D., additional, Yulin, S., additional, Feigl, T., additional, Rehbein, S., additional, Guttmann, P., additional, Schneider, G., additional, Wiesemann, U., additional, Wirtz, M., additional, and Diete, W., additional
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- 2012
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16. Dumbarton Bridge (California, USA)
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Seim, C.
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- 1982
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17. Beyond engineering: The politics of Maracaibo.
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Manzanarez, R. and Seim, C.
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BRIDGES - Abstract
Offers recommendations by investigating engineers for halting the deterioration of a world-class Venezuelan bridge, the Maracaibo. The structure began to deteriorate soon after construction, mainly from pollution and lack of maintenance. Details the problems with the bridge, especially corrosion. Findings; Work beyond engineering.
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- 1991
18. Soft x-ray nanoscale imaging using highly brilliant laboratory sources and new detector concepts
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Klisnick, Annie, Menoni, Carmen S., Stiel, H., Braenzel, J., Dehlinger, A., Jung, R., Luebcke, A., Regehly, M., Ritter, S., Tuemmler, J., Schnuerer, M., and Seim, C.
- Published
- 2017
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19. Daily Vibrotactile Stimulation Exhibits Equal or Greater Spasticity Relief Than Botulinum Toxin in Stroke.
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Seim C, Chen B, Han C, Vacek D, Lowber A, Lansberg M, and Okamura AM
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- Humans, Middle Aged, Muscle Spasticity drug therapy, Muscle Spasticity etiology, Prospective Studies, Treatment Outcome, Botulinum Toxins, Type A therapeutic use, Stroke complications, Stroke Rehabilitation, Neuromuscular Agents
- Abstract
Objective: To test the feasibility and efficacy of the VibroTactile Stimulation (VTS) Glove, a wearable device that provides VTS to the impaired limb to reduce spastic hypertonia., Design: Prospective 2-arm intervention study-including 1 group of patients who use Botulinum toxin (BTX-A) for spasticity and 1 group of patients who do not use BTX-A., Setting: Participants were recruited through rehabilitation and neurology clinics., Participants: Patients with chronic stroke (N=20; mean age=54 years, mean time since stroke=6.9 years). Patients who were previously receiving the standard of care (BTX-A injection) were eligible to participate and started the intervention 12 weeks after their last injection., Intervention: Participants were instructed to use the VTS Glove for 3 hours daily, at home or during everyday activities, for 8 weeks., Main Outcome Measures: Spasticity was assessed with the Modified Ashworth Scale and the Modified Tardieu Scale at baseline and then at 2-week intervals for 12 weeks. Primary outcomes were the difference from baseline and at week 8 (end of VTS Glove use) and week 12 (4 weeks after stopping VTS Glove use). Patients who were receiving BTX-A were also assessed during the 12 weeks preceding the start of VTS Glove use to monitor the effect of BTX-A on spastic hypertonia. Range of motion and participant feedback were also studied., Results: A clinically meaningful difference in spastic hypertonia was found during and after daily VTS Glove use. Modified Ashworth and Modified Tardieu scores were reduced by an average of 0.9 (P=.0014) and 0.7 (P=.0003), respectively, at week 8 of daily VTS Glove use, and by 1.1 (P=.00025) and 0.9 (P=.0001), respectively, 1 month after stopping VTS Glove use. For participants who used BTX-A, 6 out of 11 showed greater change in Modified Ashworth ratings during VTS Glove use (mean=-1.8 vs mean=-1.6 with BTX-A) and 8 out of 11 showed their lowest level of symptoms during VTS Glove use (vs BTX-A)., Conclusions: Daily stimulation from the VTS Glove provides relief of spasticity and hypertonia. For more than half of the participants who had regularly used BTX-A, the VTS Glove provided equal or greater symptom relief., (Copyright © 2023. Published by Elsevier Inc.)
- Published
- 2023
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20. Relief of post-stroke spasticity with acute vibrotactile stimulation: controlled crossover study of muscle and skin stimulus methods.
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Seim C, Chen B, Han C, Vacek D, Wu LS, Lansberg M, and Okamura A
- Abstract
Background: Prior work suggests that vibratory stimulation can reduce spasticity and hypertonia. It is unknown which of three predominant approaches (stimulation of the spastic muscle, antagonist muscle, or cutaneous regions) most reduces these symptoms., Objective: Determine which vibrotactile stimulation approach is most effective at reducing spastic hypertonia among post-stroke patients., Methods: Sham-controlled crossover study with random assignment of condition order in fourteen patients with post-stroke hand spasticity. All patients were studied in four conditions over four visits: three stimulation conditions and a sham control. The primary outcome measure was the Modified Ashworth Scale, and the secondary outcome measure was the Modified Tardieu Scale measured manually and using 3D motion capture. For each condition, measures of spastic hypertonia were taken at four time points: baseline, during stimulation, after stimulation was removed, and after a gripping exercise., Results: A clinically meaningful difference in spastic hypertonia was found during and after cutaneous stimulation of the hand. Modified Ashworth and Modified Tardieu scores were reduced by a median of 1.1 (SD = 0.84, p = 0.001) and 0.75 (SD = 0.65, p = 0.003), respectively, during cutaneous stimulation, and by 1.25 (SD = 0.94, p = 0.001) and 0.71 (SD = 0.67, p = 0.003), respectively, at 15 min after cutaneous stimulation. Symptom reductions with spastic muscle stimulation and antagonist muscle stimulation were non-zero but not significant. There was no change with sham stimulation., Conclusions: Cutaneous vibrotactile stimulation of the hand provides significant reductions in spastic hypertonia, compared to muscle stimulation., Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03814889., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Seim, Chen, Han, Vacek, Wu, Lansberg and Okamura.)
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- 2023
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21. Quantitative Element-Sensitive Analysis of Individual Nanoobjects.
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Wählisch A, Unterumsberger R, Hönicke P, Lubeck J, Kayser Y, Weser J, Dai G, Hahm K, Weimann T, Seim C, Rehbein S, and Beckhoff B
- Abstract
A reliable and quantitative material analysis is crucial for assessing new technological processes, especially to facilitate a quantitative understanding of advanced material properties at the nanoscale. To this end, X-ray fluorescence microscopy techniques can offer an element-sensitive and non-destructive tool for the investigation of a wide range of nanotechnological materials. Since X-ray radiation provides information depths of up to the microscale, even stratified or buried arrangements are easily accessible without invasive sample preparation. However, in terms of the quantification capabilities, these approaches are usually restricted to a qualitative or semi-quantitative analysis at the nanoscale. Relying on comparable reference nanomaterials is often not straightforward or impossible because the development of innovative nanomaterials has proven to be more fast-paced than any development process for appropriate reference materials. The present work corroborates that a traceable quantification of individual nanoobjects can be realized by means of an X-ray fluorescence microscope when utilizing rather conventional but well-calibrated instrumentation instead of reference materials. As a proof of concept, the total number of atoms forming a germanium nanoobject is quantified using soft X-ray radiation. Furthermore, complementary dimensional parameters of such objects are reconstructed., (© 2022 The Authors. Small published by Wiley-VCH GmbH.)
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- 2023
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22. Conductance Switching in Liquid Crystal-Inspired Self-Assembled Monolayer Junctions.
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Dlugosch JM, Seim H, Bora A, Kamiyama T, Lieberman I, May F, Müller-Plathe F, Nefedov A, Prasad S, Resch S, Saller K, Seim C, Speckbacher M, Voges F, Tornow M, and Kirsch P
- Abstract
We present the prototype of a ferroelectric tunnel junction (FTJ), which is based on a self-assembled monolayer (SAM) of small, functional molecules. These molecules have a structure similar to those of liquid crystals, and they are embedded between two solid-state electrodes. The SAM, which is deposited through a short sequence of simple fabrication steps, is extremely thin (3.4 ± 0.5 nm) and highly uniform. The functionality of the FTJ is ingrained in the chemical structure of the SAM components: a conformationally flexible dipole that can be reversibly reoriented in an electrical field. Thus, the SAM acts as an electrically switchable tunnel barrier. Fabricated stacks of Al/Al
2 O3 /SAM/Pb/Ag with such a polar SAM show pronounced hysteretic, reversible conductance switching at voltages in the range of ±2-3 V, with a conductance ratio of the low and the high resistive states of up to 100. The switching mechanism is analyzed using a combination of quantum chemical, molecular dynamics, and tunneling resistance calculation methods. In contrast to more common, inorganic material-based FTJs, our approach using SAMs of small organic molecules allows for a high degree of functional complexity and diversity to be integrated by synthetic standard methods, while keeping the actual device fabrication process robust and simple. We expect that this technology can be further developed toward a level that would then allow its application in the field of information storage and processing, in particular for in-memory and neuromorphic computing architectures.- Published
- 2022
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23. Biocompatibility Analyses of HF-Passivated Magnesium Screws for Guided Bone Regeneration (GBR).
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Jung O, Hesse B, Stojanovic S, Seim C, Weitkamp T, Batinic M, Goerke O, Kačarević ŽP, Rider P, Najman S, and Barbeck M
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- Animals, Bone Regeneration genetics, Cell Line, Coated Materials, Biocompatible chemistry, Coated Materials, Biocompatible pharmacology, Humans, Hydrofluoric Acid chemistry, Hydrofluoric Acid pharmacology, Magnesium adverse effects, Materials Testing, Mice, Orthognathic Surgical Procedures trends, Osteoblasts drug effects, Bone Regeneration drug effects, Bone Screws adverse effects, Guided Tissue Regeneration, Magnesium pharmacology
- Abstract
Background: Magnesium (Mg) is one of the most promising materials for human use in surgery due to material characteristics such as its elastic modulus as well as its resorbable and regenerative properties. In this study, HF-coated and uncoated novel bioresorbable magnesium fixation screws for maxillofacial and dental surgical applications were investigated in vitro and in vivo to evaluate the biocompatibility of the HF coating. Methods: Mg alloy screws that had either undergone a surface treatment with hydrofluoric-acid (HF) or left untreated were investigated. In vitro investigation included XTT, BrdU and LDH in accordance with the DIN ISO 10993-5/-12. In vivo, the screws were implanted into the tibia of rabbits. After 3 and 6 weeks, degradation, local tissue reactions and bony integration were analyzed histopathologically and histomorphometrically. Additionally, SEM/EDX analysis and synchrotron phase-contrast microtomography (µCT) measurements were conducted. The in vitro analyses revealed that the Mg screws are cytocompatible, with improved results when the surface had been passivated with HF. In vivo, the HF-treated Mg screws implanted showed a reduction in gas formation, slower biodegradation and a better bony integration in comparison to the untreated Mg screws. Histopathologically, the HF-passivated screws induced a layer of macrophages as part of its biodegradation process, whereas the untreated screws caused a slight fibrous tissue reaction. SEM/EDX analysis showed that both screws formed a similar layer of calcium phosphates on their surfaces and were surrounded by bone. Furthermore, the µCT revealed the presence of a metallic core of the screws, a faster absorbing corrosion front and a slow absorbing region of corroded magnesium. Conclusions: Overall, the HF-passivated Mg fixation screws showed significantly better biocompatibility in vitro and in vivo compared to the untreated screws.
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- 2021
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24. Microdistribution of Magnetic Resonance Imaging Contrast Agents in Atherosclerotic Plaques Determined by LA-ICP-MS and SR-μXRF Imaging.
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Uca YO, Hallmann D, Hesse B, Seim C, Stolzenburg N, Pietsch H, Schnorr J, and Taupitz M
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- Angiography, Animals, Atherosclerosis diagnostic imaging, Extracellular Matrix metabolism, Ferric Compounds chemistry, Gadolinium chemistry, Iron chemistry, Macrophages pathology, Magnetite Nanoparticles chemistry, Male, Metal Nanoparticles chemistry, Rabbits, Synchrotrons, Contrast Media chemistry, Magnetic Resonance Imaging methods, Mass Spectrometry methods, Plaque, Atherosclerotic diagnostic imaging, X-Ray Diffraction methods
- Abstract
Purpose: Contrast-enhanced magnetic resonance imaging (MRI) has the potential to replace angiographic evaluation of atherosclerosis. While studies have investigated contrast agent (CA) uptake in atherosclerotic plaques, exact CA spatial distribution on a microscale is elusive. The purpose of this study was to investigate the microdistribution of gadolinium (Gd)- and iron (Fe) oxide-based CA in atherosclerotic plaques of New Zealand White rabbits., Procedures: The study was performed as a post hoc analysis of archived tissue specimens obtained in a previous in vivo MRI study conducted to investigate signal changes induced by very small superparamagnetic iron oxide nanoparticles (VSOP) and Gd-BOPTA. For analytical discrimination from endogenous Fe, VSOP were doped with europium (Eu) resulting in Eu-VSOP. Formalin-fixed arterial specimens were cut into 5-μm serial sections and analyzed by immunohistochemistry (IHC: Movat's pentachrome, von Kossa, and Alcian blue (pH 1.0) staining, anti-smooth muscle cell actin (anti-SMA), and anti-rabbit macrophage (anti-RAM-11) immunostaining) and elemental microscopy with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and synchrotron radiation μX-ray fluorescence (SR-μXRF) spectroscopy. Elemental distribution maps of Fe, Eu, Gd, sulfur (S), phosphorus (P), and calcium (Ca) were investigated., Results: IHC characterized atherosclerotic plaque pathomorphology. Elemental microscopy showed S distribution to match the anatomy of arterial vessel wall layers, while P distribution corresponded well with cellular areas. LA-ICP-MS revealed Gd and Fe with a limit of detection of ~ 0.1 nmol/g and ~ 100 nmol/g, respectively. Eu-positive signal identified VSOP presence in the vessel wall and allowed the comparison of Eu-VSOP and endogenous Fe distribution in tissue sections. Extracellular matrix material correlated with Eu signal intensity, Fe concentration, and maximum Gd concentration. Eu-VSOP were confined to endothelium in early lesions but accumulated in cellular areas in advanced plaques. Gd distribution was homogeneous in healthy arteries but inhomogeneous in early and advanced plaques. SR-μXRF scans at 0.5 μm resolution revealed Gd hotspots with increased P and Ca concentrations at the intimomedial interface, and a size distribution ranging from a few micrometers to submicrometers., Conclusions: Eu-VSOP and Gd have distinct spatial distributions in atherosclerotic plaques. While Eu-VSOP distribution is more cell-associated and might be used to monitor atherosclerotic plaque progression, Gd distribution indicates arterial calcification and might help in characterizing plaque vulnerability.
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- 2021
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25. Laboratory Soft X-Ray Microscopy with an Integrated Visible-Light Microscope-Correlative Workflow for Faster 3D Cell Imaging.
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Dehlinger A, Seim C, Stiel H, Twamley S, Ludwig A, Kördel M, Grötzsch D, Rehbein S, and Kanngießer B
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- Humans, Imaging, Three-Dimensional, Synchrotrons, Workflow, X-Rays, Laboratories, Microscopy
- Abstract
Laboratory transmission soft X-ray microscopy (L-TXM) has emerged as a complementary tool to synchrotron-based TXM and high-resolution biomedical 3D imaging in general in recent years. However, two major operational challenges in L-TXM still need to be addressed: a small field of view and a potentially misaligned rotation stage. As it is not possible to alter the magnification during operation, the field of view in L-TXM is usually limited to a few tens of micrometers. This complicates locating areas and objects of interest in the sample. Additionally, if the rotation axis of the sample stage cannot be adjusted prior to the experiments, an efficient workflow for tomographic imaging cannot be established, as refocusing and sample repositioning will become necessary after each recorded projection. Both these limitations have been overcome with the integration of a visible-light microscope (VLM) into the L-TXM system. Here, we describe the calibration procedure of the goniometer sample stage and the integrated VLM and present the resulting 3D imaging of a test sample. In addition, utilizing this newly integrated VLM, the extracellular matrix of cryofixed THP-1 cells (human acute monocytic leukemia cells) was visualized by L-TXM for the first time in the context of an ongoing biomedical research project.
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- 2020
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26. Identification of pigments related to allergic tattoo reactions in 104 human skin biopsies.
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Serup J, Hutton Carlsen K, Dommershausen N, Sepehri M, Hesse B, Seim C, Luch A, and Schreiver I
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- Adult, Allergens adverse effects, Female, Humans, Ink, Male, Tandem Mass Spectrometry, Coloring Agents adverse effects, Dermatitis, Allergic Contact etiology, Pigments, Biological adverse effects, Tattooing adverse effects
- Abstract
Background: Red tattoos are prone to allergic reactions. The identity of the allergen(s) is mostly unknown., Objectives: Chemical analysis of human skin biopsies from chronic allergic reactions in red tattoos to identify culprit pigment(s) and metals., Material and Methods: One hundred four dermatome biopsies were analyzed by matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS) for identification of commonly used organic pigments. Metal concentrations were assessed by inductively coupled plasma (ICP)-MS and x-ray fluorescence (XRF). Fourteen patients had cross-reactions in other red tattoos., Results: In total, the identified pigments were mainly azo Pigment Red (P.R.) 22 (35%), P.R. 210 (24%), P.R. 170 (12%), P.R. 5 (0.9%), P.R. 112 (0.9%), and Pigment Orange (P.O.) 13 (11%). P.R. 122 (0.9%) and Pigment Violet (P.V.) 23 (8%) were also common. P.R. 22, P.R. 170, and P.R. 210 also dominated in patients with cross-reactions. In 22% of the biopsies, no red pigment was detected. Element analysis indicated the presence of the sensitizers nickel and chromium., Conclusions: P.R. 22, P.R. 170, and P.R. 210 were identified as the prevailing pigments behind chronic allergic reactions in red tattoos. The epitope causing the reaction might be a pigment-degradation product. Metal contamination may derive from different sources, and its role in red tattoo allergy cannot be ascertained., (© 2019 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)
- Published
- 2020
- Full Text
- View/download PDF
27. Distribution of nickel and chromium containing particles from tattoo needle wear in humans and its possible impact on allergic reactions.
- Author
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Schreiver I, Hesse B, Seim C, Castillo-Michel H, Anklamm L, Villanova J, Dreiack N, Lagrange A, Penning R, De Cuyper C, Tucoulou R, Bäumler W, Cotte M, and Luch A
- Subjects
- Animals, Coloring Agents pharmacokinetics, Humans, Hypersensitivity immunology, Hypersensitivity metabolism, In Vitro Techniques, Ink, Lymph Nodes immunology, Lymph Nodes metabolism, Nanoparticles metabolism, Nanoparticles toxicity, Needles, Particle Size, Skin immunology, Skin metabolism, Swine, Tissue Distribution, Titanium pharmacokinetics, Titanium toxicity, Chromium pharmacokinetics, Coloring Agents toxicity, Hypersensitivity etiology, Lymph Nodes drug effects, Nickel pharmacokinetics, Skin drug effects, Tattooing adverse effects
- Abstract
Background: Allergic reactions to tattoos are amongst the most common side effects occurring with this permanent deposition of pigments into the dermal skin layer. The characterization of such pigments and their distribution has been investigated in recent decades. The health impact of tattoo equipment on the extensive number of people with inked skin has been the focus of neither research nor medical diagnostics. Although tattoo needles contain high amounts of sensitizing elements like nickel (Ni) and chromium (Cr), their influence on metal deposition in skin has never been investigated., Results: Here, we report the deposition of nano- and micrometer sized tattoo needle wear particles in human skin that translocate to lymph nodes. Usually tattoo needles contain nickel (6-8%) and chromium (15-20%) both of which prompt a high rate of sensitization in the general population. As verified in pig skin, wear significantly increased upon tattooing with the suspected abrasive titanium dioxide white when compared to carbon black pigment. Additionally, scanning electron microscopy of the tattoo needle revealed a high wear after tattooing with ink containing titanium dioxide. The investigation of a skin biopsy obtained from a nickel sensitized patient with type IV allergy toward a tattoo showed both wear particles and iron pigments contaminated with nickel., Conclusion: Previously, the virtually inevitable nickel contamination of iron pigments was suspected to be responsible for nickel-driven tattoo allergies. The evidence from our study clearly points to an additional entry of nickel to both skin and lymph nodes originating from tattoo needle wear with an as yet to be assessed impact on tattoo allergy formation and systemic sensitization.
- Published
- 2019
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28. A calibration procedure for a traceable contamination analysis on medical devices by combined X-ray spectrometry and ambient spectroscopic techniques.
- Author
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Pollakowski-Herrmann B, Hornemann A, Giovannozzi AM, Green F, Gunning P, Portesi C, Rossi A, Seim C, Steven R, Tyler B, and Beckhoff B
- Subjects
- Calibration, Reference Standards, Reproducibility of Results, Spectrometry, Mass, Secondary Ion, Spectroscopy, Fourier Transform Infrared, Spectrum Analysis, Raman, Equipment Contamination, Equipment and Supplies, Spectrometry, X-Ray Emission standards, Stearic Acids analysis
- Abstract
There is a strong need in the medical device industry to decrease failure rates of biomedical devices by reducing the incidence of defect structures and contaminants during the production process. The detection and identification of defect structures and contaminants is crucial for many industrial applications. The present study exploits reference-free X-ray fluorescence (XRF) analysis as an analytical tool for the traceable characterization of surface contaminants of medical devices, in particular N,N'-ethylene-bis (stearamide), an ubiquitous compound used in many industrial applications as a release agent or friction reduction additive. Reference-free XRF analysis as primary method has been proven to be capable of underpinning all other applied methods since it yields the absolute mass deposition of the selected N,N'-ethylene-bis (stearamide) contaminant whilst X-ray absorption fine structure analysis determines the chemical species. Ambient vibrational spectroscopy and mass spectroscopy methodologies such as Fourier transform infrared, Raman, and secondary ion mass spectroscopy have been used in this systematic procedure providing an extensive range of complementary analyses. The calibration procedure described in this paper was developed using specially designed and fabricated model systems varying in thickness and substrate material. Furthermore, typical real medical devices such as both a polyethylene hip liner and a silver-coated wound dressing have been contaminated and investigated by these diverse methods, enabling testing of this developed procedure. These well-characterized samples may be used as calibration standards for bench top instrumentation from the perspective of providing traceable analysis of biomaterials and surface treatments. These findings demonstrate the potential importance and usefulness of combining complementary methods for a better understanding of the relevant organic materials., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2018
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29. Are metals involved in tattoo-related hypersensitivity reactions? A case report.
- Author
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de Cuyper C, Lodewick E, Schreiver I, Hesse B, Seim C, Castillo-Michel H, Laux P, and Luch A
- Subjects
- Humans, Male, Middle Aged, Patch Tests, Spinal Fractures surgery, Thoracic Vertebrae surgery, Bone Plates adverse effects, Dermatitis, Allergic Contact etiology, Prostheses and Implants adverse effects, Tattooing adverse effects
- Abstract
Background: Allergic reactions to tattoos are not uncommon. However, identification of the culprit allergen(s) remains challenging., Objectives: We present a patient with papulo-nodular infiltration of 20-year-old tattoos associated with systemic symptoms that disappeared within a week after surgical removal of metal osteosynthesis implants from his spine. We aimed to explore the causal relationship between the metal implants and the patient's clinical presentation., Methods: Metal implants and a skin biopsy of a reactive tattoo were analysed for elemental contents by inductively coupled plasma mass spectrometry and synchrotron-based X-ray fluorescence (XRF) spectroscopy., Results: Nickel (Ni) and chromium (Cr) as well as high levels of titanium (Ti) and aluminium were detected in both the skin biopsy and the implants. XRF analyses identified Cr(III), with Cr(VI) being absent. Patch testing gave negative results for Ni and Cr. However, patch tests with an extract of the implants and metallic Ti on the tattooed skin evoked flare-up of the symptoms., Conclusion: The patient's hypersensitivity reaction and its spontaneous remission after removal of the implants indicate that Ti, possibly along with some of the other metals detected, could have played a major role in this particular case of tattoo-related allergy., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
- Published
- 2017
- Full Text
- View/download PDF
30. Synchrotron-based ν-XRF mapping and μ-FTIR microscopy enable to look into the fate and effects of tattoo pigments in human skin.
- Author
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Schreiver I, Hesse B, Seim C, Castillo-Michel H, Villanova J, Laux P, Dreiack N, Penning R, Tucoulou R, Cotte M, and Luch A
- Subjects
- Biological Transport, Coloring Agents chemistry, Humans, Lymph Nodes pathology, Organometallic Compounds chemistry, Particle Size, Microscopy, Skin pathology, Skin Pigmentation, Spectroscopy, Fourier Transform Infrared, Tattooing methods
- Abstract
The increasing prevalence of tattoos provoked safety concerns with respect to particle distribution and effects inside the human body. We used skin and lymphatic tissues from human corpses to address local biokinetics by means of synchrotron X-ray fluorescence (XRF) techniques at both the micro (μ) and nano (ν) scale. Additional advanced mass spectrometry-based methodology enabled to demonstrate simultaneous transport of organic pigments, heavy metals and titanium dioxide from skin to regional lymph nodes. Among these compounds, organic pigments displayed the broadest size range with smallest species preferentially reaching the lymph nodes. Using synchrotron μ-FTIR analysis we were also able to detect ultrastructural changes of the tissue adjacent to tattoo particles through altered amide I α-helix to β-sheet protein ratios and elevated lipid contents. Altogether we report strong evidence for both migration and long-term deposition of toxic elements and tattoo pigments as well as for conformational alterations of biomolecules that likely contribute to cutaneous inflammation and other adversities upon tattooing.
- Published
- 2017
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31. Reconstruction of confocal micro-X-ray fluorescence spectroscopy depth scans obtained with a laboratory setup.
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Mantouvalou I, Wolff T, Seim C, Stoytschew V, Malzer W, and Kanngiesser B
- Abstract
Depth profiling with confocal micro-X-ray fluorescence spectroscopy (confocal micro-XRF) is a nondestructive analytical method for obtaining elemental depth profiles in the micrometer region. Up until now, the quantitative reconstruction of thicknesses and elemental concentration of stratified samples has been only possible with monochromatic, thus, synchrotron radiation. In this work, we present a new calibration and reconstruction procedure, which renders quantification in the laboratory feasible. The proposed model uses the approximation of an effective spot size of the optic in the excitation channel and relies on the calibration of the transmission of this lens beforehand. Calibration issues are discussed and validation measurements on thick multielement reference material and a stratified system are presented.
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- 2014
- Full Text
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32. [Amaurosis fugax with myocardial amyloidosis (author's transl)].
- Author
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Schütz HJ, Seim CE, and Hachmeister U
- Subjects
- Adult, Amyloidosis pathology, Blindness pathology, Cardiomyopathies pathology, Cerebral Infarction etiology, Coronary Disease complications, Coronary Disease pathology, Humans, Male, Myocardium pathology, Amyloidosis complications, Blindness etiology, Cardiomyopathies complications, Ischemic Attack, Transient etiology
- Published
- 1981
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