SENSOREN – AKTUELLER STAND UND HERAUSFORDERUNGEN

Sensoren sind Basiselemente, um Informationen aus der Umgebung aufzunehmen und elektronisch weiterzuverarbeiten. Sie haben wesentlich die innovativen Entwicklungen in den zurückliegenden 15 Jahren bestimmt. An ausgewählten Beispielen wird das komplexe Gebiet der Sensorik dargestellt und die Bedeutung von Sensoranwendungen in unterschiedlichsten Bereichen gezeigt. Eigene Beiträge zu resonanten Sensoren werden dargestellt. Dabei stehen Ultraschallsensoren und akustische Mikrosensoren im Mittelpunkt. Sensoren werden auch in der Zukunft eine wichtige Rolle spielen. Deshalb werden Trends abgeschätzt

MPI Phantom Study with A High-Performing Multicore Tracer Made by Coprecipitation

Magnetic particle imaging (MPI) is a new imaging technique that detects the spatial distribution of magnetic nanoparticles (MNP) with the option of high temporal resolution. MPI relies on particular MNP as tracers with tailored characteristics for improvement of sensitivity and image resolution. For this reason, we developed optimized multicore particles (MCP 3) made by coprecipitation via synthesis of green rust and subsequent oxidation to iron oxide cores consisting of a magnetite/maghemite mixed phase. MCP 3 shows high saturation magnetization close to that of bulk maghemite and provides excellent magnetic particle spectroscopy properties which are superior to Resovist® and any other up to now published MPI tracers made by coprecipitation. To evaluate the MPI characteristics of MCP 3 two kinds of tube phantoms were prepared and investigated to assess sensitivity, spatial resolution, artifact severity, and selectivity. Resovist® was used as standard of comparison. For image reconstruction, the regularization factor was optimized, and the resulting images were investigated in terms of quantifying of volumes and iron content. Our results demonstrate the superiority of MCP 3 over Resovist® for all investigated MPI characteristics and suggest that MCP 3 is promising for future experimental in vivo studies

Iron(III)‐tCDTA derivatives as MRI contrast agents: Increased T 1 relaxivities at higher magnetic field strength and pH sensing

Purpose: Low molecular weight iron(III) complex-based contrast agents (IBCA) including iron(III) trans-cyclohexane diamine tetraacetic acid [Fe(tCDTA)](-) could serve as alternatives to gadolinium-based contrast agents in MRI. In search for IBCA with enhanced properties, we synthesized derivatives of [Fe(tCDTA)](-) and compared their contrast effects. Methods: Trans-cyclohexane diamine tetraacetic acid (tCDTA) was chemically modified in 2 steps: first the monoanhydride of Trans-cyclohexane diamine tetraacetic acid was generated, and then it was coupled to amines in the second step. After purification, the chelators were analyzed by high-performance liquid chromatography, mass spectrometry, and NMR spectrometry. The chelators were complexed with iron(III), and the relaxivities of the complexes were measured at 0.94, 1.5, 3, and 7 Tesla. Kinetic stabilities of the complexes were analyzed spectrophotometrically and the redox properties by cyclic voltammetry. Results: Using ethylenediamine (en) and trans-1,4-diaminocyclohexane, we generated monomers and dimers of tCDTA: en-tCDTA, en-tCDTA-dimer, trans-1,4-diaminocyclohexane-tCDTA, and trans-1,4-diaminocyclohexane-tCDTA-dimer. The iron(III) complexes of these derivatives had similarly high stabilities as [Fe(tCDTA)](-). The iron(III) complexes of the trans-1,4-diaminocyclohexane derivatives had higher T-1 relaxivities than [Fe(tCDTA)](-) that increased with increasing magnetic field strengths and were highest at 6.8 L.mmol(-1).s(-1) per molecule for the dimer. Remarkably, the relaxivity of [Fe(en-tCDTA)](+) had a threefold increase from neutral pH toward pH6. Conclusion: Four iron(III) complexes with similar stability in comparison to [Fe(tCDTA)](-) were synthesized. The relaxivities of trans-1,4-diaminocyclohexane-tCDTA and trans-1,4-diaminocyclohexane-tCDTA-dimer complexes were in the same range as gadolinium-based contrast agents at 3 Tesla. The [Fe(en-tCDTA)](+) complex is a pH sensor at weakly acidic pH levels, which are typical for various cancer types

Sex Differences in Clinical Course and Intensive Care Unit Admission in a National Cohort of Hospitalized Patients with COVID-19

Males have a higher risk for an adverse outcome of COVID-19. The aim of the study was to analyze sex differences in the clinical course with focus on patients who received intensive care. Research was conducted as an observational retrospective cohort study. A group of 23,235 patients from 83 hospitals with PCR-confirmed infection with SARS-CoV-2 between 4 February 2020 and 22 March 2021 were included. Data on symptoms were retrieved from a separate registry, which served as a routine infection control system. Males accounted for 51.4% of all included patients. Males received more intensive care (ratio OR = 1.61, 95% CI = 1.51–1.71) and mechanical ventilation (invasive or noninvasive, OR = 1.87, 95% CI = 1.73–2.01). A model for the prediction of mortality showed that until the age 60 y, mortality increased with age with no substantial difference between sexes. After 60 y, the risk of death increased more in males than in females. At 90 y, females had a predicted mortality risk of 31%, corresponding to males of 84 y. In the intensive care unit (ICU) cohort, females of 90 y had a mortality risk of 46%, equivalent to males of 72 y. Seventy-five percent of males over 90 died, but only 46% of females of the same age. In conclusion, the sex gap was most evident among the oldest in the ICU. Understanding sex-determined differences in COVID-19 can be useful to facilitate individualized treatments

Iron(III)‐tCDTA derivatives as MRI contrast agents

Purpose Low molecular weight iron(III) complex‐based contrast agents (IBCA) including iron(III) trans‐cyclohexane diamine tetraacetic acid [Fe(tCDTA)]− could serve as alternatives to gadolinium‐based contrast agents in MRI. In search for IBCA with enhanced properties, we synthesized derivatives of [Fe(tCDTA)]− and compared their contrast effects. Methods Trans‐cyclohexane diamine tetraacetic acid (tCDTA) was chemically modified in 2 steps: first the monoanhydride of Trans‐cyclohexane diamine tetraacetic acid was generated, and then it was coupled to amines in the second step. After purification, the chelators were analyzed by high‐performance liquid chromatography, mass spectrometry, and NMR spectrometry. The chelators were complexed with iron(III), and the relaxivities of the complexes were measured at 0.94, 1.5, 3, and 7 Tesla. Kinetic stabilities of the complexes were analyzed spectrophotometrically and the redox properties by cyclic voltammetry. Results Using ethylenediamine (en) and trans‐1,4‐diaminocyclohexane, we generated monomers and dimers of tCDTA: en‐tCDTA, en‐tCDTA‐dimer, trans‐1,4‐diaminocyclohexane‐tCDTA, and trans‐1,4‐diaminocyclohexane‐tCDTA‐dimer. The iron(III) complexes of these derivatives had similarly high stabilities as [Fe(tCDTA)]−. The iron(III) complexes of the trans‐1,4‐diaminocyclohexane derivatives had higher T1 relaxivities than [Fe(tCDTA)]− that increased with increasing magnetic field strengths and were highest at 6.8 L·mmol−1·s−1 per molecule for the dimer. Remarkably, the relaxivity of [Fe(en‐tCDTA)]+ had a threefold increase from neutral pH toward pH6. Conclusion Four iron(III) complexes with similar stability in comparison to [Fe(tCDTA)]− were synthesized. The relaxivities of trans‐1,4‐diaminocyclohexane‐tCDTA and trans‐1,4‐diaminocyclohexane‐tCDTA‐dimer complexes were in the same range as gadolinium‐based contrast agents at 3 Tesla. The [Fe(en‐tCDTA)]+ complex is a pH sensor at weakly acidic pH levels, which are typical for various cancer types.DFGPeer ReviewedPeer Reviewe