120 results on '"Kranz C"'
Search Results
2. P112 Real-time estimation of individual long- and short-term lung functions trends in persons with cystic fibrosis within the Swedish cystic fibrosis registry
- Author
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Svedberg, M., primary, Hagel, E., additional, Kranz, C., additional, and Imberg, H., additional
- Published
- 2024
- Full Text
- View/download PDF
3. Electrocatalytically modified microelectrodes for the detection of hydrogen peroxide at blood cells from swine with induced trauma
- Author
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Hellmann, A., Daboss, S., Zink, F., Hartmann, C., Radermacher, P., and Kranz, C.
- Published
- 2020
- Full Text
- View/download PDF
4. Capa do livro: Psicologia e educação especial: desenvolvimento humano, formação e atuação profissional Psicologia e educação especial: desenvolvimento humano, formação e atuação profissional
- Author
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FACCI, M. G. D., primary, Anache, Alexandra Ayach, additional, Machado, Aliciene Fusca Cordeiro, additional, Ciantelli, Ana Paula Camilo, additional, Fernandes, Bruna Fernanda Ferreira, additional, KRANZ, C. R., additional, Moraes, Dayane Suelen de, additional, Almeida, Denise Mesquita de Melo, additional, BARBOSA, D. E. P., additional, GONÇALVES, F. M. S., additional, ARIAS, G.B, additional, Parruque, Hélio Daniel, additional, CAMPOS, H. R., additional, TADA, I. N. C., additional, LEITE, Lúcia Pereira, additional, SCHLINDWEIN, L. M., additional, RIBEIRO, Maria Júlia Lemes, additional, SIMIONATO, Marlene Aparecida Wischral, additional, SOUZA, M. P. R., additional, ALMEIDA, M. N., additional, SÓRIS, S. S., additional, BARROCO, S. M. S., additional, and AMARAL, T. P., additional
- Published
- 2020
- Full Text
- View/download PDF
5. In situ investigation of copper corrosion in acidic chloride solution using atomic force—scanning electrochemical microscopy
- Author
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Izquierdo, J., Eifert, A., Kranz, C., and Souto, R.M.
- Published
- 2017
- Full Text
- View/download PDF
6. Macroscopic and microscopic electrochemical investigation of Clostridium botulinum C2IIa embedded in supported lipid membranes
- Author
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Frey, C.M., Eifert, A., Schütz, H., Barth, H., Mizaikoff, B., and Kranz, C.
- Published
- 2016
- Full Text
- View/download PDF
7. SIMULTANEOUS ATOMIC FORCE—SCANNING ELECTROCHEMICAL MICROSCOPY (AFM-SECM) IMAGING OF COPPER DISSOLUTION
- Author
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Izquierdo, J., Fernández-Pérez, B.M., Eifert, A., Souto, R.M., and Kranz, C.
- Published
- 2016
- Full Text
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8. Investigation of the Anode-Electrolyte Interface in a Magnesium Full-Cell with Fluorinated Alkoxyborate-Based Electrolyte
- Author
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Roy, A., Bhagavathi Parambath, V., Diemant, T., Neusser, G., Kranz, C., Behm, R. J., Li, Z., Zhao-Karger, Z., and Fichtner, M.
- Subjects
Technology ,ddc:600 - Abstract
Magnesium (Mg) anode-electrolyte interaction is not trivial and investigation of the interfacial process can be helpful for the development of Mg batteries. In this work, we studied the Mg metal anode cycled in a chloride (Cl)-free magnesium tetrakis (hexafluoroisopropyloxy) borate electrolyte using a full-cell configuration with TiS$_{2}$ model cathode. Electrochemical measurements and structural analysis of the cathode showed reversible de-/magnesiation of TiS$_{2}$ with some entrapment of irreversibly bound Mg$^{2+}$. Electrochemical impedance spectroscopy (EIS) was applied to analyze the Mg-electrolyte interaction in a three-electrode system. The results showed a rapid increase in charge transfer resistance on the anode side with increasing resting time. In contrast, we observed a significant drop in the charge transfer impedance upon cycling along with the appearance of an additional semi-circle, which suggested to the development of a solid interphase. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) corroborated the EIS results and confirmed the solid interphase layer formation, in which MgF$_{2}$ was identified as the primary species contributing to its formation. The current study provides fundamental insights into the interfacial phenomena between the metallic Mg anode and Cl-free electrolyte by highlighting the role played by the formed interphase on the reversible Mg stripping and plating in a Mg full-cell.
- Published
- 2022
- Full Text
- View/download PDF
9. Toward a Combined SECM-IR-ATR System For the Investigation of Conductive Polymers
- Author
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Wang, Liqun, primary, Moon, Jong-Seok, additional, Mizaikoff, Boris, additional, and Kranz, C., additional
- Published
- 2019
- Full Text
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10. Patella Baja und Patella Pseudo Baja. Inzidenz und Outcome nach distalem Femurersatz oder proximalem Tibiaersatz
- Author
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Graulich, T, Kranz, C, Örgel, M, Haertle, M, Omar, M, Krettek, C, and Panzica, M
- Subjects
ddc: 610 ,Revisionsendoprothetik ,610 Medical sciences ,Medicine ,Patella Baja ,Patella Pseudo Baja - Abstract
Fragestellung: Nach Implantation einer primären Kniegelenksendoprothese konnte gezeigt werden, dass das Vorliegen einer Patella Pseudo Baja (PPB), also die relative Verkürzung der Patellasehne durch eine Erhöhung der Gelenklinie, das postoperative Ergebnis negativ beeinflusst (Behrend[zum vollständigen Text gelangen Sie über die oben angegebene URL], Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2019)
- Published
- 2019
- Full Text
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11. Investigation of modified nanopore arrays using FIB/SEM tomography
- Author
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Holzinger, A., Neusser, G., Austen, B., Gamero-Quijano, A., Herzog, G., Arrigan, Damien, Ziegler, A., Walther, P., Kranz, C., Holzinger, A., Neusser, G., Austen, B., Gamero-Quijano, A., Herzog, G., Arrigan, Damien, Ziegler, A., Walther, P., and Kranz, C.
- Abstract
The investigation of electrochemical processes at the interface of two immiscible electrolyte solutions (ITIES) is of great interest for sensing applications, and serves as a surrogate to the study of biological transport phenomena, e.g. ion channels. Alongside e-beam lithography, focused ion beam (FIB) milling is an attractive method to prototype and fabricate nanopore arrays that support nanoITIES. Within this contribution, we explore the capability of FIB/scanning electron microscopy (SEM) tomography to visualize the actual pore structure and interfaces at silica-modified nanoporous membranes. The nanopores were also characterized by atomic force microscopy (AFM) using ultra-sharp AFM probes to determine the pore diameter, and using scanning transmission electron microscopy (STEM) and energy dispersive X-ray (EDX) spectroscopy, providing additional information on the elemental composition of deposits within the pores. Si-rich particles could be identified within the pores as well as at the orifice that had faced the organic electrolyte solution during electrochemical deposition. The prospects of the used techniques for investigating the interface at or within FIB-milled nanopores will be discussed.
- Published
- 2018
12. Bifacial PERC+ Solar Cells and Modules: An Overview
- Author
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Dullweber, T., Schulte-Huxel, H., Kranz, C., Blankemeyer, S., Baumann, U., Witteck, R., Peibst, R., Köntges, M., Brendel, R., and Yao, Y.
- Subjects
Homojunction Solar Cells ,Silicon Photovoltaics - Abstract
33rd European Photovoltaic Solar Energy Conference and Exhibition; 649-656, Since its first publication in 2015, the PERC+ cell concept has been rapidly adopted by several solar cell manufacturers worldwide. The fast industrial implementation is facilitated by the very similar process technology of bifacial PERC+ cells and main stream monofacial PERC cells. Conversion efficiencies of industrial PERC+ solar cells up to 21.6% with front side illumination and 17.3% with rear side illumination were reported. Meanwhile, four companies are offering commercial bifacial PERC+ modules with maximum rating power around 300 Wp when illuminated from the front side, only. These modules apply 60 PERC+ cells with 4 or 5 busbars, which are interconnected by conventional stringing and tabbing technology. First small scale outdoor installations verify an increase of the energy yield relative to monofacial PERC modules between 13% and 22%. Two large scale out door installations with 2 MWp and 20 MWp are under construction in Taiwan and China, respectively. We report for the first time in detail on a novel bifacial PERC+ prototype module by applying the Smart Wire Connection Technology. We interconnect 18 halved PERC+ solar cells by soldering 18 wires directly to the Ag front and Al rear fingers. The resulting prototype module exhibits independently confirmed front and rear side efficiencies of 19.8% and 16.4%, respectively. Additionally, Meyer Burger certified a full-size PERC+ SWCT module according to the IEC 61215 norm thereby demonstrating the long term reliability of this novel module technology.
- Published
- 2017
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13. Horizontal black lipid bilayer membranes for studying pore-forming toxins
- Author
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Frey, C. M., primary, Barth, H., additional, Kranz, C., additional, and Mizaikoff, B., additional
- Published
- 2018
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14. Electrochemical Biosensing: From the Bench to the Real World
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Arrigan, Damien, Kranz, C., Lee, H.J., Arrigan, Damien, Kranz, C., and Lee, H.J.
- Published
- 2017
15. Simultaneous pit generation and visualization of pit topography using combined atomic force–scanning electrochemical microscopy
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Izquierdo, J., Eifert, A., Souto, R.M., and Kranz, C.
- Published
- 2015
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16. Inhibiting P. fluorescens biofilms with fluoropolymer-embedded silver nanoparticles: an in-situ spectroscopic study
- Author
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Sportelli, M. C., primary, Tütüncü, E., additional, Picca, R. A., additional, Valentini, M., additional, Valentini, A., additional, Kranz, C., additional, Mizaikoff, B., additional, Barth, H., additional, and Cioffi, N., additional
- Published
- 2017
- Full Text
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17. FIB and MIP: understanding nanoscale porosity in molecularly imprinted polymers via 3D FIB/SEM tomography
- Author
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Neusser, G., primary, Eppler, S., additional, Bowen, J., additional, Allender, C. J., additional, Walther, P., additional, Mizaikoff, B., additional, and Kranz, C., additional
- Published
- 2017
- Full Text
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18. Breakdown of the Efficiency Gap to 29% Based on Experimental Input Data and Modelling
- Author
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Brendel, R., Dullweber, T., Peibst, R., Kranz, C., Merkle, A., and Walter, D.
- Subjects
WAFER-BASED SILICON SOLAR CELLS AND MATERIALS TECHNOLOGY ,Silicon Feedstock, Crystallisation and Wafering - Abstract
31st European Photovoltaic Solar Energy Conference and Exhibition; 264-272, We demonstrate a procedure for quantifying efficiency gains that treats resistive, recombinative, and optical losses on an equal footing. For this we apply our Conductive Boundary (CoBo) model as implemented in the Quokka cell simulator. The generation profile is calculated with a novel analytical light trapping model. This model parametrizes the measured reflection spectra and is capable of turning the experimental case gradually into an ideal Lambertian scheme. Simulated and measured short circuit current densities agree for our 21.2%-efficient screen-printed PERC cell and for our 23.4%-efficient ion-implanted laser-processed IBC cell. For the loss analysis of these two cells we set all experimentally accessible control parameters (e.g. saturation current densities, sheet resistances, and carrier lifetimes) one at a time to ideal values. The efficiency gap to the ultimate limit of 29% is thereby fully explained in terms of individual improvements and in terms of their respective synergistic effects. This approach allows comparing loss structures of different types of solar cells, e.g. PERC and IBC cells.
- Published
- 2015
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19. Progress in transparent diamond microelectrode arrays
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Granado, T. C., Neusser, G., Kranz, C., Filho, J. B. D., Carabelli, Valentina, Carbone, Emilio, and Pasquarelli, A.
- Subjects
secretion ,Diamond, lab-on-chip, secretion, chromaffin cells, catecholamines ,Diamond ,chromaffin cells ,catecholamines ,lab-on-chip - Published
- 2015
20. The PERC+ Cell: a 21%-Efficient Industrial Bifacial PERC Solar Cell
- Author
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Dullweber, T., Kranz, C., Peibst, R., Baumann, U., Hannebauer, H., Fülle, A., Steckemetz, S., Weber, T., Kutzer, M., Müller, M., Fischer, G., Palinginis, P., and Neuhaus, D.H.
- Subjects
WAFER-BASED SILICON SOLAR CELLS AND MATERIALS TECHNOLOGY ,Silicon Solar Cell Improvements - Abstract
31st European Photovoltaic Solar Energy Conference and Exhibition; 341-350, Passivated Emitter and Rear Cell (PERC) solar cells are currently being introduced into mass production. In this paper we report a novel PERC solar cell design which applies a screen-printed rear Al finger grid instead of the conventional full-area aluminum (Al) rear layer while using the same PERC manufacturing sequence. We name this novel cell concept PERC+ since it offers several advantages. In particular, the Al paste consumption of the PERC+ cells is drastically reduced to 0.15 g instead of 1.6 g for the conventional PERC cells. The Al fingers create 2 μm deeper Al-BSFs which increases the open circuit voltage by 3 mV. The 5 busbar Al finger grid enables bifacial applications of the PERC+ cells with front side efficiencies up to 21.2% and rear side efficiencies up to 16.7% measured with a black chuck. The corresponding bifaciality is up to 80.0%. When measured with a reflective brass chuck, the PERC+ cells demonstrate efficiencies up to 21.5% compared to conventional PERC cells with 21.1% efficiency. Whereas ISFH developed the aforementioned PERC+ results, SolarWorld independently pioneered a very similar bifacial PERC+ cell process starting in 2014. Transfer into mass production has been successfully accomplished and novel glass-glass bifacial PERC+ modules have been launched at the Intersolar 2015 based on a most simple, lean and cost-effective bifacial cell process. These new bifacial PERC+ modules show an increase in annual energy yield between 5 and 25% in simulations which is confirmed by first outdoor measurements.
- Published
- 2015
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21. Visualization of Diffusion within Nanoarrays
- Author
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Liu, Yang, Holzinger, A., Knittel, P., Poltorak, L., Gamero-Quijano, A., Rickard, William, Walcarius, A., Herzog, G., Kranz, C., Arrigan, Damien, Liu, Yang, Holzinger, A., Knittel, P., Poltorak, L., Gamero-Quijano, A., Rickard, William, Walcarius, A., Herzog, G., Kranz, C., and Arrigan, Damien
- Abstract
The direct experimental characterization of diffusion processes at nanoscale remains a challenge that could help elucidate processes in biology, medicine and technology. In this report, two experimental approaches were employed to visualize ion diffusion profiles at the orifices of nanopores (radius (ra) of 86 ± 6 nm) in array format: (1) electrochemically assisted formation of silica deposits based on surfactant ion transfer across nanointerfaces between two immiscible electrolyte solutions (nanoITIES); (2) combined atomic force - scanning electrochemical microscopy (AFM-SECM) imaging of topography and redox species diffusion through the nanopores. The nature of the diffusion zones formed around the pores is directly related to the interpore distance within the array. Nanopore arrays with different ratios of pore center-to-center separation (rc) to pore radius (ra) were fabricated by focused ion beam (FIB) milling of silicon nitride (SiN) membranes, with 100 pores in a hexagonal arrangement. The ion diffusion profiles determined by the two visualization methods indicated the formation of overlapped or independent diffusion profiles at nanopore arrays with rc/ra ratios of 21 ± 2 and 91 ± 7, respectively. In particular, the silica deposition method resulted in formation of a single deposit encompassing the complete array with closer nanopore arrangement, whereas individual silica deposits were formed around each nanopore within the more widely spaced array. The methods reveal direct experimental evidence of diffusion zones at nanopore arrays and provide practical illustration that the pore-pore separation within such arrays has a significant impact on diffusional transport as the pore size is reduced to the nanoscale. These approaches to nanoscale diffusion zone visualization open up possibilities for better understanding of molecular transport processes within miniaturized systems.
- Published
- 2016
22. Challenges in nanoelectrochemical and nanomechanical studies of individual anisotropic gold nanoparticles
- Author
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Knittel, P., primary, Bibikova, O., additional, and Kranz, C., additional
- Published
- 2016
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23. Probing the PEDOT:PSS/cell interface with conductive colloidal probe AFM-SECM
- Author
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Knittel, P., primary, Zhang, H., additional, Kranz, C., additional, Wallace, G. G., additional, and Higgins, M. J., additional
- Published
- 2016
- Full Text
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24. Achievement of diffusional independence at nanoscale liquid-liquid interfaces within arrays
- Author
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Liu, Yang, Sairi, M., Neusser, G., Kranz, C., Arrigan, Damien, Liu, Yang, Sairi, M., Neusser, G., Kranz, C., and Arrigan, Damien
- Abstract
In this work, independent radial diffusion at arrayed nanointerfaces between two immiscible electrolyte solutions (nanoITIES) was achieved. The arrays were formed at nanopores fabricated by focused ion beam milling of silicon nitride (SiN) membranes, enabling the reproducible and systematic design of five arrays with different ratios of pore center-to-center distance (rc) to pore radius (ra). Voltammetry across water–1,6-dichlorohexane nanoITIES formed at these arrays was examined by the interfacial transfer of tetrapropylammonium ions. The diffusion-limited ion-transfer current increased with the ratio rc/ra, reaching a plateau for rc/ra ≥ 56, which was equivalent to the theoretical current for radial diffusion to an array of independent nanoITIES. As a result, mass transport to the nanoITIES arrays was greatly enhanced due to the decreased overlap of diffusion zones at adjacent nanoITIES, allowing each interface in the array to behave independently. When the rc/ra ratio increased from 13 to 56, the analytical performance parameters of sensitivity and limit of detection were improved from 0.50 (±0.02) A M–1 to 0.76 (±0.02) A M–1 and from 0.101 (±0.003) μM to 0.072 (±0.002) μM, respectively. These results provide an experimental basis for the design of arrayed nanointerfaces for electrochemical sensing.
- Published
- 2015
25. Electrochemical Characterisation of Nanoscale Liquid | Liquid Interfaces Located at Focused Ion Beam-Milled Silicon Nitride Membranes
- Author
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Sairi, M., Chen-Tan, Nigel, Neusser, G., Kranz, C., Arrigan, Damien, Sairi, M., Chen-Tan, Nigel, Neusser, G., Kranz, C., and Arrigan, Damien
- Abstract
The electrochemical behaviour of single and arrayed nanoscale interfaces between two immiscible electrolyte solutions (single and array nanoITIES) is presented. The interfaces were formed at nanopores fabricated through the focused ion beam (FIB) milling of silicon nitride (SiN) membranes by using nanopores with approximately 30–80 nm radii and with pore-to-pore separations to pore radius ratios in the range of 16–32. Electrochemistry was performed through the interfacial transfer of tetrapropylammonium (TPrA+) across single and array nanoITIES between water and 1,6-dichlorohexane. The ion-transfer limiting current at the single nanoITIES was in excellent agreement with the current predicted by using an inlaid disc interface model. At nanoITIES arrays, experimental currents were lower than predicted for an array of inlaid interfaces, which is attributed to overlapped diffusion zones. As a result, FIB milling offers an attractive strategy to form nanoITIES for diverse investigations.
- Published
- 2015
26. The mechanisms of platinum-catalyzed silicon nanowire growth
- Author
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Hibst, N, primary, Knittel, P, additional, Biskupek, J, additional, Kranz, C, additional, Mizaikoff, B, additional, and Strehle, S, additional
- Published
- 2015
- Full Text
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27. In situ investigation of copper corrosion in acidic chloride solution using atomic force—scanning electrochemical microscopy.
- Author
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Eifert, A., Kranz, C., Izquierdo, J., and Souto, R.M.
- Subjects
- *
COPPER corrosion , *CHLORIDES , *ATOMIC force microscopy , *COPPER ions , *IN situ microanalysis , *HEAT exchanger industry , *KELVIN probe force microscopy - Abstract
The anodic dissolution of pure copper surfaces in acidic chloride solution has been monitored in-situ using combined atomic force − scanning electrochemical microscopy (AFM-SECM). Here, the initial studies performed on model copper-modified substrates have been extended to the investigation of bulk copper samples used in industrial settings. The local release of Cu 2+ ions was monitored through electrochemical reduction and deposition of the metal ions on the conductive frame of the AFM-SECM probe. Simultaneous monitoring of the topographical changes due to the corrosion process allowed the distinction and correlation of local passivation and pitting phenomena. The extent of the attack was estimated by anodic stripping of the copper metal deposited at the probe. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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28. Beam-deposited platinum as versatile catalyst for bottom-up silicon nanowire synthesis
- Author
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Hibst, N., primary, Knittel, P., additional, Kranz, C., additional, Mizaikoff, B., additional, and Strehle, S., additional
- Published
- 2014
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29. Antibacterial Action of Zn 2+ Ions Driven by the In Vivo Formed ZnO Nanoparticles.
- Author
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Vitasovic T, Caniglia G, Eghtesadi N, Ceccato M, Bo Jesen ED, Gosewinkel U, Neusser G, Rupp U, Walther P, Kranz C, and Ferapontova EE
- Subjects
- Metal Nanoparticles chemistry, Metal Nanoparticles toxicity, Zinc chemistry, Zinc pharmacology, Ions chemistry, Microbial Sensitivity Tests, Reactive Oxygen Species metabolism, Hydrogen-Ion Concentration, Nanocomposites chemistry, Zinc Oxide chemistry, Zinc Oxide pharmacology, Escherichia coli drug effects, Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents chemistry
- Abstract
Antibacterial formulations based on zinc oxide nanoparticles (ZnO NPs) are widely used for antibiotic replacement in veterinary medicine and animal nutrition. However, the undesired environmental impact of ZnO NPs triggers a search for alternative, environmentally safer solutions. Here, we show that Zn
2+ in its ionic form is a more eco-friendly antibacterial, and its biocidal action rivals that of ZnO NPs (<100 nm size), with a minimal biocidal concentration being 41(82) μg mL-1 vs 5 μg mL-1 of ZnO NPs, as determined for 103 (106 ) CFU mL-1 E. coli . We demonstrate that the biocidal activity of Zn2+ ions is primarily associated with their uptake by E. coli and spontaneous in vivo transformation into insoluble ZnO nanocomposites at an internal bacterial pH of 7.7. Formed in vivo nanocomposite then damages E. coli membrane and intracellular components from the inside, by forming insoluble biocomposites, whose formation can also trigger ZnO characteristic reactions damaging the cells (e.g., by generation of high-potential reactive oxygen species). Our study defines a special route in which Zn2+ metal ions induce the death of bacterial cells, which might be common to other metal ions capable of forming semiconductor oxides and insoluble hydroxides at a slightly alkaline intracellular pH of some bacteria.- Published
- 2024
- Full Text
- View/download PDF
30. Antimicrobial effects of silver nanoparticle-microspots on the mechanical properties of single bacteria.
- Author
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Caniglia G, Valavanis D, Tezcan G, Magiera J, Barth H, Bansmann J, Kranz C, and Unwin PR
- Subjects
- Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents chemistry, Microscopy, Atomic Force, Polymers chemistry, Polymers pharmacology, Bacterial Adhesion drug effects, Indoles chemistry, Indoles pharmacology, Silver chemistry, Silver pharmacology, Metal Nanoparticles chemistry, Escherichia coli drug effects
- Abstract
Silver nanoparticles (AgNPs) conjugated with polymers are well-known for their powerful and effective antimicrobial properties. In particular, the incorporation of AgNPs in biocompatible catecholamine-based polymers, such as polydopamine (PDA), has recently shown promising antimicrobial activity, due to the synergistic effects of the AgNPs, silver(I) ions released and PDA. In this study, we generated AgNPs-PDA-patterned surfaces by localised electrochemical depositions, using a double potentiostatic method via scanning electrochemical cell microscopy (SECCM). This technique enabled the assessment of a wide parameter space in a high-throughput manner. The optimised electrodeposition process resulted in stable and homogeneously distributed AgNP-microspots, and their antimicrobial activity against Escherichia coli was assessed using atomic force microscopy (AFM)-based force spectroscopy, in terms of bacterial adhesion and cell elasticity. We observed that the bacterial outer membrane underwent significant structural changes, when in close proximity to the AgNPs, namely increased hydrophilicity and stiffness loss. The spatially varied antimicrobial effect found experimentally was rationalised by numerical simulations of silver(I) concentration profiles.
- Published
- 2024
- Full Text
- View/download PDF
31. Modification of Al Surface via Acidic Treatment and its Impact on Plating and Stripping.
- Author
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Rahide F, Palanisamy K, Flowers JK, Hao J, Stein HS, Kranz C, Ehrenberg H, and Dsoke S
- Abstract
Amorphous Al
2 O3 film that naturally exists on any Al substrate is a critical bottleneck for the cyclic performance of metallic Al in rechargeable Al batteries. The so-called electron/ion insulator Al oxide slows down the anode's activation and hinders Al plating/stripping. The Al2 O3 film induces different surface properties (roughness and microstructure) on the metal. Al foils present two optically different sides (shiny and non-shiny), but their surface properties and influence on plating and stripping have not been studied so far. Compared to the shiny side, the non-shiny one has a higher (~28 %) surface roughness, and its greater concentration of active sites (for Al plating and stripping) yields higher current densities. Immersion pretreatments in Ionic-Liquid/AlCl3 -based electrolyte with various durations modify the surface properties of each side, forming an electrode-electrolyte interphase layer rich in Al, Cl, and N. The created interphase layer provides more tunneling paths for better Al diffusion upon plating and stripping. After 500 cycles, dendritic Al deposition, generated active sites, and the continuous removal of the Al metal and oxide cause accelerated local corrosion and electrode pulverization. We highlight the mechanical surface properties of cycled Al foil, considering the role of immersion pretreatment and the differences between the two sides., (© 2023 The Authors. ChemSusChem published by Wiley-VCH GmbH.)- Published
- 2024
- Full Text
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32. Pt-Black-Modified (Hemi)spherical AFM Sensors: In Situ Imaging of Light-Driven Hydrogen Peroxide Evolution.
- Author
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Hellmann A, Neusser G, Daboss S, Elnagar MM, Liessem J, Mitoraj D, Beranek R, Arbault S, and Kranz C
- Abstract
In this work, we present (hemi)spherical atomic force microscopy (AFM) sensors for the detection of hydrogen peroxide. Platinum-black (Pt-B) was electrodeposited onto conductive colloidal AFM probes or directly at recessed microelectrodes located at the end of a tipless cantilever, resulting in electrocatalytically active cantilever-based sensors that have a small geometric area but, due to the porosity of the films, exhibit a large electroactive surface area. Focused ion beam-scanning electron microscopy tomography revealed the porous 3D structure of the deposited Pt-B. Given the accurate positioning capability of AFM, these probes are suitable for local in situ sensing of hydrogen peroxide and at the same time can be used for (electrochemical) force spectroscopy measurements. Detection limits for hydrogen peroxide in the nanomolar range (LOD = 68 ± 7 nM) were obtained. Stability test and first in situ proof-of-principle experiments to achieve the electrochemical imaging of hydrogen peroxide generated at a microelectrode and at photocatalytically active structured poly(heptazine imide) films are demonstrated. Force spectroscopic data of the photocatalyst films were recorded in ambient conditions, in solution, and by applying a potential, which demonstrates the versatility of these novel Pt-B-modified spherical AFM probes.
- Published
- 2024
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- View/download PDF
33. Initial Quenching Efficiency Determines Light-Driven H 2 Evolution of [Mo 3 S 13 ] 2- in Lipid Bilayers.
- Author
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Abbas A, Oswald E, Romer J, Lenzer A, Heiland M, Streb C, Kranz C, and Pannwitz A
- Subjects
- Dimyristoylphosphatidylcholine chemistry, Photosensitizing Agents, Phospholipids chemistry, Lipid Bilayers chemistry, Liposomes chemistry
- Abstract
Nature uses reactive components embedded in biological membranes to perform light-driven photosynthesis. Here, a model artificial photosynthetic system for light-driven hydrogen (H
2 ) evolution is reported. The system is based on liposomes where amphiphilic ruthenium trisbipyridine based photosensitizer (RuC9 ) and the H2 evolution reaction (HER) catalyst [Mo3 S13 ]2- are embedded in biomimetic phospholipid membranes. When DMPC was used as the main lipid of these light-active liposomes, increased catalytic activity (TONCAT ~200) was observed compared to purely aqueous conditions. Although all tested lipid matrixes, including DMPC, DOPG, DPPC and DOPG liposomes provided similar liposomal structures according to TEM analysis, only DMPC yielded high H2 amounts. In situ scanning electrochemical microscopy (SECM) measurements using Pd microsensors revealed an induction period of around 26 minutes prior to H2 evolution, indicating an activation mechanism which might be induced by the fluid-gel phase transition of DMPC at room temperature. Stern-Volmer-type quenching studies revealed that electron transfer dynamics from the excited state photosensitizer are most efficient in the DMPC lipid environment giving insight for design of artificial photosynthetic systems using lipid bilayer membranes., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)- Published
- 2023
- Full Text
- View/download PDF
34. Thin-Film Waveguide Laser Spectroscopy: A Novel Platform for Bacterial Analysis.
- Author
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Teuber A, Caniglia G, Barth H, Kranz C, and Mizaikoff B
- Subjects
- Spectroscopy, Fourier Transform Infrared, Diamond chemistry, Escherichia coli, Lasers
- Abstract
Bacterial sensing based on quantum cascade laser spectroscopy coupled with diamond or gallium arsenide thin-film waveguides is a novel analytical tool for gaining high-resolution infrared spectroscopic information of planktonic and sessile bacteria, as shown in the present study for Escherichia coli . During observation periods of up to 24 h, diamond and gallium arsenide thin-film waveguide laser spectroscopy was compared to information obtained via conventional Fourier transform infrared spectroscopy. The proliferation behavior of E. coli at those surfaces was complementarily investigated using atomic force microscopy and scanning electron microscopy.
- Published
- 2023
- Full Text
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35. Understanding the effects of overnight vital signs monitoring on sleep duration and disruptions in hospitalized children: A scoping review.
- Author
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Bitterfeld L, Mathias J, Waldron BP, and Kranz C
- Subjects
- Child, Humans, Sleep, Critical Care methods, Vital Signs, Child, Hospitalized, Sleep Duration
- Abstract
Problem: Overnight vital signs are typically taken every four hours on pediatric acute care units, despite limited evidence supporting the efficacy of this practice. Vital signs are often ordered and collected without considering the patient's clinical status or potential impact that they may have on sleep. We sought to understand the impact that overnight vital sign monitoring has on sleep duration and disruptions among hospitalized children in an acute care setting., Eligibility Criteria: We conducted a scoping review using the Preferred Reporting Items for Systematic Reviews and Meta-analysis Protocols extension for scoping reviews (PRISMA-ScR). Studies were included if they addressed the relationship between vital signs monitoring and sleep among children hospitalized in an acute care unit., Sample: Eleven studies from 2012 to 2022 were included in the final review., Results: Vital signs monitoring is the most common sleep disruptor among hospitalized children in acute care units and early evidence suggests that minimizing overnight vital signs may be a safe intervention for clinically stable children. Methods for measuring sleep duration and disruptions are heterogenous and validated tools are not often used. Finally, nurses report comfort with forgoing overnight vital signs when their patient's clinical status is stable., Conclusion: Despite a lack of evidence regarding the efficacy of every 4 h vital signs, overnight vital signs monitoring is consistently the greatest disruptor to sleep for hospitalized children., Implications: Nurses should play a central role in guiding vital signs monitoring that maintains safety and improves sleep in hospitalized children., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)
- Published
- 2023
- Full Text
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36. Graphene-enhanced quantum cascade laser infrared spectroscopy using diamond thin-film waveguides.
- Author
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Teuber A, Caniglia G, Kranz C, and Mizaikoff B
- Abstract
Diamond thin-film waveguides were combined with quantum cascade lasers augmented by drop-casted graphene enabling surface-enhanced infrared absorption spectroscopy. Enhancing the signal provides access to an even more pronounced vibrational signature suitable for analytical scenarios where only a small sample volume and/or low analyte concentration levels are prevalent. To demonstrate the utility of this concept, taurine was investigated as a model analyte.
- Published
- 2023
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- View/download PDF
37. Reversible Electrodeposition of Potassium-bridged Molecular Vanadium Oxides: A New Approach Towards Multi-Electron Storage.
- Author
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Arya N, Philipp T, Greiner S, Steiner M, Kranz C, and Anjass M
- Abstract
Molecular metal oxides, so-called polyoxometalates (POMs), have shown outstanding performance as catalysts and lately attracted interest as materials in energy conversion and storage systems due to their capability of storing and exchanging multiple electrons. Here, we report the first example of redox-driven reversible electrodeposition of molecular vanadium oxide clusters, leading to the formation of thin films. The detailed investigation of the deposition mechanism reveals that the reversibility is dependent on the reduction potential. Correlating electrochemical quartz microbalance studies with X-ray photoelectron spectroscopy (XPS) data gave insight into the redox chemistry and oxidation states of vanadium in the deposited films in dependence on the potential window. A multi-electron reduction of the polyoxovanadate cluster, which facilitates the potassium (K
+ ) cation-assisted reversible formation of potassium vanadium oxide thin films was confirmed. At anodic potentials, re-oxidation of the polyoxovanadate and complete stripping of the thin film is observed for films deposited at potentials more positive than -500 mV vs. Ag/Ag+ , while electrodeposition at more negative cathodic potential reduces the electrochemical reversibility of the process and increases the stripping overpotential. As proof of principle, we demonstrate the electrochemical performance of the deposited films for potential use in potassium-ion batteries., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)- Published
- 2023
- Full Text
- View/download PDF
38. Espresso Science: Laser-Based Diamond Thin-Film Waveguide Sensors for the Quantification of Caffeine.
- Author
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Teuber A, Caniglia G, Wild M, Godejohann M, Kranz C, and Mizaikoff B
- Subjects
- Spectroscopy, Fourier Transform Infrared methods, Lasers, Caffeine, Diamond chemistry
- Abstract
Diamond thin-film waveguides with a nanocrystalline diamond layer of approximately 20 μm thickness were used in the mid-infrared regime in combination with quantum cascade lasers to detect the IR signature of caffeine. The diamond thin-film waveguides were fundamentally characterized with respect to their morphological properties via AFM and SEM. Theoretical simulations confirmed the feasibility of using a larger sensing area of approximately 50 mm
2 compared to conventionally used strip waveguides. A comprehensive and comparative analysis confirmed the performance of the diamond thin-film-waveguide-based sensing system vs data obtained via conventional attenuated total reflection Fourier transform infrared spectroscopy using a single-bounce diamond internal reflection element. Hence, the utility of innovative diamond thin-film-waveguide-based sensors coupled with quantum cascade laser light sources has been confirmed as an innovative analytical tool, which may be used in a wide range of application scenarios, ranging from environmental to medical sensing, taking advantage of the robustness and inertness of nanocrystalline diamond.- Published
- 2023
- Full Text
- View/download PDF
39. Multimodal Analysis of Light-Driven Water Oxidation in Nanoporous Block Copolymer Membranes.
- Author
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Kund J, Kruse JH, Gruber A, Trentin I, Langer M, Read C, Neusser G, Blaimer D, Rupp U, Streb C, Leopold K, Schacher FH, and Kranz C
- Abstract
Heterogeneous light-driven catalysis is a cornerstone of sustainable energy conversion. Most catalytic studies focus on bulk analyses of the hydrogen and oxygen evolved, which impede the correlation of matrix heterogeneities, molecular features, and bulk reactivity. Here, we report studies of a heterogenized catalyst/photosensitizer system using a polyoxometalate water oxidation catalyst and a model, molecular photosensitizer that were co-immobilized within a nanoporous block copolymer membrane. Via operando scanning electrochemical microscopy (SECM), light-induced oxygen evolution was determined using sodium peroxodisulfate (Na
2 S2 O8 ) as sacrificial electron acceptor. Ex situ element analyses provided spatially resolved information on the local concentration and distribution of the molecular components. Infrared attenuated total reflection (IR-ATR) studies of the modified membranes showed no degradation of the water oxidation catalyst under the reported light-driven conditions., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)- Published
- 2023
- Full Text
- View/download PDF
40. Atomic force and infrared spectroscopic studies on the role of surface charge for the anti-biofouling properties of polydopamine films.
- Author
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Caniglia G, Teuber A, Barth H, Mizaikoff B, and Kranz C
- Subjects
- Biofilms, Indoles chemistry, Bacterial Adhesion, Microscopy, Atomic Force, Spectroscopy, Fourier Transform Infrared methods, Surface Properties, Polymers chemistry, Biofouling
- Abstract
Antibacterial polymer materials have gained interest due to their capability to inhibit or eradicate biofilms with greater efficiency in comparison with their monomeric counterparts. Among the antimicrobial and anti-biofouling polymers, catecholamine-based polymers - and in particular polydopamine - have been studied due to their favorable adhesion properties, which can be tuned by controlling the pH value. In this study, we used atomic force microscopy (AFM)-based spectroscopy to investigate the relation between the adhesion properties and surface charge density and the pH of electrochemically deposited polydopamine films presenting a dissociation constant of polydopamine of 6.3 ± 0.2 and a point of zero charge of 5.37 ± 0.06. Furthermore, using AFM and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), the influence of the surface charge density of polydopamine on bacterial adhesion and biofilm formation was investigated. It was shown that the adhesion of Escherichia coli at positively charged polydopamine is three times higher compared to a negatively charged polymer, and that the formation of biofilms is favored at positively charged polymers., (© 2022. The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
41. The effect of sodium thiosulfate on immune cell metabolism during porcine hemorrhage and resuscitation.
- Author
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Wolfschmitt EM, Hogg M, Vogt JA, Zink F, Wachter U, Hezel F, Zhang X, Hoffmann A, Gröger M, Hartmann C, Gässler H, Datzmann T, Merz T, Hellmann A, Kranz C, Calzia E, Radermacher P, and Messerer DAC
- Subjects
- Animals, Swine, Leukocytes, Mononuclear metabolism, Bayes Theorem, Hemorrhage, Lipids, Shock, Hemorrhagic metabolism
- Abstract
Introduction: Sodium thiosulfate (Na
2 S2 O3 ), an H2 S releasing agent, was shown to be organ-protective in experimental hemorrhage. Systemic inflammation activates immune cells, which in turn show cell type-specific metabolic plasticity with modifications of mitochondrial respiratory activity. Since H2 S can dose-dependently stimulate or inhibit mitochondrial respiration, we investigated the effect of Na2 S2 O3 on immune cell metabolism in a blinded, randomized, controlled, long-term, porcine model of hemorrhage and resuscitation. For this purpose, we developed a Bayesian sampling-based model for13 C isotope metabolic flux analysis (MFA) utilizing 1,2-13 C2 -labeled glucose,13 C6 -labeled glucose, and13 C5 -labeled glutamine tracers., Methods: After 3 h of hemorrhage, anesthetized and surgically instrumented swine underwent resuscitation up to a maximum of 68 h. At 2 h of shock, animals randomly received vehicle or Na2 S2 O3 (25 mg/kg/h for 2 h, thereafter 100 mg/kg/h until 24 h after shock). At three time points (prior to shock, 24 h post shock and 64 h post shock) peripheral blood mononuclear cells (PBMCs) and granulocytes were isolated from whole blood, and cells were investigated regarding mitochondrial oxygen consumption (high resolution respirometry), reactive oxygen species production (electron spin resonance) and fluxes within the metabolic network (stable isotope-based MFA)., Results: PBMCs showed significantly higher mitochondrial O2 uptake and lower O 2 • - production in comparison to granulocytes. We found that in response to Na2 S2 O3 administration, PBMCs but not granulocytes had an increased mitochondrial oxygen consumption combined with a transient reduction of the citrate synthase flux and an increase of acetyl-CoA channeled into other compartments, e.g., for lipid biogenesis., Conclusion: In a porcine model of hemorrhage and resuscitation, Na2 S2 O3 administration led to increased mitochondrial oxygen consumption combined with stimulation of lipid biogenesis in PBMCs. In contrast, granulocytes remained unaffected. Granulocytes, on the other hand, remained unaffected. O 2 • - concentration in whole blood remained constant during shock and resuscitation, indicating a sufficient anti-oxidative capacity. Overall, our MFA model seems to be is a promising approach for investigating immunometabolism; especially when combined with complementary methods., 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. The reviewer JB declared a past collaboration with the authors E-MW, MG and MH to the handling editor., (Copyright © 2023 Wolfschmitt, Hogg, Vogt, Zink, Wachter, Hezel, Zhang, Hoffmann, Gröger, Hartmann, Gässler, Datzmann, Merz, Hellmann, Kranz, Calzia, Radermacher and Messerer.)- Published
- 2023
- Full Text
- View/download PDF
42. In situ monitoring of Lentilactobacillus parabuchneri biofilm formation via real-time infrared spectroscopy.
- Author
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Bajrami D, Fischer S, Barth H, Sarquis MA, Ladero VM, Fernández M, Sportelli MC, Cioffi N, Kranz C, and Mizaikoff B
- Subjects
- Biofilms, Stainless Steel, Extracellular Polymeric Substance Matrix, Lactobacillus
- Abstract
Foodborne pathogenic microorganisms form biofilms at abiotic surfaces, which is a particular challenge in food processing industries. The complexity of biofilm formation requires a fundamental understanding on the involved molecular mechanisms, which may then lead to efficient prevention strategies. In the present study, biogenic amine producing bacteria, i.e., Lentilactobacillus parabuchneri DSM 5987 strain isolated from cheese were studied in respect with biofilm formation, which is of substantial relevance given their contribution to the presence of histamine in dairy products. While scanning electron microscopy was used to investigate biofilm adhesion at stainless steel surfaces, in situ infrared attenuated total reflection spectroscopy (IR-ATR) using a custom flow-through assembly was used for real-time and non-destructive observations of biofilm formation during a period of several days. The spectral window of 1700-600 cm
-1 provides access to vibrational signatures characteristic for identifying and tracking L. parabuchneri biofilm formation and maturation. Especially, the amide I and II bands, lactic acid produced as the biofilm matures, and a pronounced increase of bands characteristic for extracellular polymeric substances (EPS) provide molecular insight into biofilm formation, maturation, and changes in biofilm architecture. Finally, multivariate data evaluation strategies were applied facilitating the unambiguous classification of the observed biofilm changes via IR spectroscopic data., (© 2022. The Author(s).)- Published
- 2022
- Full Text
- View/download PDF
43. Creating a Shared Culture of Inquiry.
- Author
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Gee P, Olsen G, Kranz C, Roberts J, Sakata T, and Srivastava R
- Subjects
- Humans, Organizational Culture
- Abstract
Competing Interests: The authors declare no conflicts of interest.
- Published
- 2022
- Full Text
- View/download PDF
44. Silver-fluoropolymer (Ag-CF X ) films: Kinetic study of silver release, and spectroscopic-microscopic insight into the inhibition of P. fluorescens biofilm formation.
- Author
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Caniglia G, Sportelli MC, Heinzmann A, Picca RA, Valentini A, Barth H, Mizaikoff B, Cioffi N, and Kranz C
- Subjects
- Anti-Bacterial Agents chemistry, Anti-Bacterial Agents pharmacology, Bacteria, Biofilms, Silver chemistry, Spectroscopy, Fourier Transform Infrared, Anti-Infective Agents pharmacology, Metal Nanoparticles chemistry
- Abstract
Silver-fluoropolymer (Ag-CF
X ) composed of encapsulated bioactive nanophases within a thin polymer coating are promising antimicrobial films with excellent bioactivity. In this contribution, we report on Ag-CFX thin films obtained by ion beam co-sputtering, accurately tuning film thickness, and inorganic loading. The Ag-CFX films were characterized by spectroscopic and scanning probe microscopy techniques with respect to composition and swelling behavior. Next to electrothermal atomic absorption spectroscopy (ETAAS) studies, scanning electrochemical microscopy (SECM) experiments in combination with anodic stripping voltammetry (ASV) were carried out to study the release mechanism of silver(I) from the embedded silver nanoparticles (AgNPs). Silver(I) concentration profiles at the Ag-CFX films in contact with water resulted in a release of 1310 ± 50 μg L-1 (n = 3) after 27 h of immersion and corresponded well to the swelling of the films. The antimicrobial properties towards biofilm formation of P. fluorescens were studied by attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy during a period of 48 h. The obtained IR data revealed biofilm inhibition due to the presence of the antimicrobial layer but also indicated potential surface re-colonization after 30 h of contact with the bacteria-containing solution. The occurrence of cyclic changes in the characteristic IR bands correlated with apparent stress of bottom-layered bacteria, along with re-colonization on top of dead biomass, indicative of potential cannibalism events., (Copyright © 2022. Published by Elsevier B.V.)- Published
- 2022
- Full Text
- View/download PDF
45. Probing and Visualizing Interfacial Charge at Surfaces in Aqueous Solution.
- Author
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Caniglia G, Tezcan G, Meloni GN, Unwin PR, and Kranz C
- Subjects
- Adsorption, Microscopy, Atomic Force methods, Surface Properties
- Abstract
Surface charge density and distribution play an important role in almost all interfacial processes, influencing, for example, adsorption, colloidal stability, functional material activity, electrochemical processes, corrosion, nanoparticle toxicity, and cellular processes such as signaling, absorption, and adhesion. Understanding the heterogeneity in, and distribution of, surface and interfacial charge is key to elucidating the mechanisms underlying reactivity, the stability of materials, and biophysical processes. Atomic force microscopy (AFM) and scanning ion conductance microscopy (SICM) are highly suitable for probing the material/electrolyte interface at the nanoscale through recent advances in probe design, significant instrumental (hardware and software) developments, and the evolution of multifunctional imaging protocols. Here, we assess the capability of AFM and SICM for surface charge mapping, covering the basic underpinning principles alongside experimental considerations. We illustrate and compare the use of AFM and SICM for visualizing surface and interfacial charge with examples from materials science, geochemistry, and the life sciences.
- Published
- 2022
- Full Text
- View/download PDF
46. Corrigendum: Cobaloxime Complex Salts: Synthesis, Patterning on Carbon Nanomembranes and Heterogeneous Hydrogen Evolution Studies.
- Author
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Oswald E, Gaus AL, Kund J, Küllmer M, Romer J, Weizenegger S, Ullrich T, Mengele AK, Petermann L, Leiter R, Unwin PR, Kaiser U, Rau S, Kahnt A, Turchanin A, von Delius M, and Kranz C
- Published
- 2022
- Full Text
- View/download PDF
47. Formation sequence of solid electrolyte interphases and impacts on lithium deposition and dissolution on copper: an in situ atomic force microscopic study.
- Author
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Wang WW, Gu Y, Yan H, Li KX, Chen ZB, Wu QH, Kranz C, Yan JW, and Mao BW
- Abstract
Copper is the most widely used substrate for Li deposition and dissolution in lithium metal anodes, which is complicated by the formation of solid electrolyte interphases (SEIs), whose physical and chemical properties can affect Li deposition and dissolution significantly. However, initial Li nucleation and growth on bare Cu creates Li nuclei that only partially cover the Cu surface so that SEI formation could proceed not only on Li nuclei but also on the bare region of the Cu surface with different kinetics, which may affect the follow-up processes distinctively. In this paper, we employ in situ atomic force microscopy (AFM), together with X-ray photoelectron spectroscopy (XPS), to investigate how SEIs formed on a Cu surface, without Li participation, and on the surface of growing Li nuclei, with Li participation, affect the components and structures of the SEIs, and how the formation sequence of the two kinds of SEIs, along with Li deposition, affect subsequent dissolution and re-deposition processes in a pyrrolidinium-based ionic liquid electrolyte containing a small amount of water. Nanoscale in situ AFM observations show that sphere-like Li deposits may have differently conditioned SEI-shells, depending on whether Li nucleation is preceded by the formation of the SEI on Cu. Models of integrated-SEI shells and segmented-SEI shells are proposed to describe SEI shells formed on Li nuclei and SEI shells sequentially formed on Cu and then on Li nuclei, respectively. "Top-dissolution" is observed for both types of shelled Li deposits, but the integrated-SEI shells only show wrinkles, which can be recovered upon Li re-deposition, while the segmented-SEI shells are apparently top-opened due to mechanical stresses introduced at the junctions of the top regions and become "dead" SEIs, which forces subsequent Li nucleation and growth in the interstice of the dead SEIs. Our work provides insights into the impact mechanism of SEIs on the initial stage Li deposition and dissolution on foreign substrates, revealing that SEIs could be more influential on Li dissolution and that the spatial integration of SEI shells on Li deposits is important to improving the reversibility of deposition and dissolution cycling.
- Published
- 2022
- Full Text
- View/download PDF
48. Potassium permanganate is an excellent alternative to osmium tetroxide in freeze-substitution.
- Author
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Schauflinger M, Bergner T, Neusser G, Kranz C, and Read C
- Subjects
- Freeze Substitution methods, Freezing, Lipids, Osmium Tetroxide, Potassium Permanganate
- Abstract
High-pressure freezing followed by freeze-substitution is a valuable method for ultrastructural analyses of resin-embedded biological samples. The visualization of lipid membranes is one of the most critical aspects of any ultrastructural study and can be especially challenging in high-pressure frozen specimens. Historically, osmium tetroxide has been the preferred fixative and staining agent for lipid-containing structures in freeze-substitution solutions. However, osmium tetroxide is not only a rare and expensive material, but also volatile and toxic. Here, we introduce the use of a combination of potassium permanganate, uranyl acetate, and water in acetone as complementing reagents during the freeze-substitution process. This mix imparts an intense en bloc stain to cellular ultrastructure and membranes, which makes poststaining superfluous and is well suited for block-face imaging. Thus, potassium permanganate can effectively replace osmium tetroxide in the freeze-substitution solution without sacrificing the quality of ultrastructural preservation., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
- View/download PDF
49. Dual signaling via interferon and DNA damage response elicits entrapment by giant PML nuclear bodies.
- Author
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Scherer M, Read C, Neusser G, Kranz C, Kuderna AK, Müller R, Full F, Wörz S, Reichel A, Schilling EM, Walther P, and Stamminger T
- Subjects
- Antiviral Agents, DNA Damage, Epigenesis, Genetic, Humans, Nuclear Bodies, Promyelocytic Leukemia Protein genetics, Transcription Factors metabolism, Interferons metabolism, Nuclear Proteins metabolism
- Abstract
PML nuclear bodies (PML-NBs) are dynamic interchromosomal macromolecular complexes implicated in epigenetic regulation as well as antiviral defense. During herpesvirus infection, PML-NBs induce epigenetic silencing of viral genomes, however, this defense is antagonized by viral regulatory proteins such as IE1 of human cytomegalovirus (HCMV). Here, we show that PML-NBs undergo a drastic rearrangement into highly enlarged PML cages upon infection with IE1-deficient HCMV. Importantly, our results demonstrate that dual signaling by interferon and DNA damage response is required to elicit giant PML-NBs. DNA labeling revealed that invading HCMV genomes are entrapped inside PML-NBs and remain stably associated with PML cages in a transcriptionally repressed state. Intriguingly, by correlative light and transmission electron microscopy (EM), we observed that PML cages also entrap newly assembled viral capsids demonstrating a second defense layer in cells with incomplete first-line response. Further characterization by 3D EM showed that hundreds of viral capsids are tightly packed into several layers of fibrous PML. Overall, our data indicate that giant PML-NBs arise via combined interferon and DNA damage signaling which triggers entrapment of both nucleic acids and proteinaceous components. This represents a multilayered defense strategy to act in a cytoprotective manner and to combat viral infections., Competing Interests: MS, CR, GN, CK, AK, RM, FF, SW, AR, ES, PW, TS No competing interests declared, (© 2022, Scherer et al.)
- Published
- 2022
- Full Text
- View/download PDF
50. Recent advances on the spectroscopic characterization of microbial biofilms: A critical review.
- Author
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Sportelli MC, Kranz C, Mizaikoff B, and Cioffi N
- Subjects
- Bacteria, Spectrum Analysis, Biofilms, Disinfectants
- Abstract
Biofilms are a major cause of health and environmental issues. Bacteria organized in biofilms are much more resistant to biocides than their equivalents in the planktonic state. In this context, spectroscopic techniques have significantly contributed to a more fundamental understanding of biofilm formation, which is crucial to prevent and limit their generation, spreading, and maturation. In this review, recent progress on the main analytical approaches enabling the spectroscopic characterization of microbial biofilms is comparatively discussed. In addition, less commonly used techniques, facilitating biofilm studies, will be also presented. Advantages and drawbacks of each discussed technique will be underlined, thus providing an overview on spectroscopic approaches for studying biofilms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
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