Lithiumpyridinyl‐Driven Synthesis of High‐Purity Zero‐Valent Iron Nanoparticles and Their Use in Follow‐Up Reactions

The synthesis of zero‐valent iron (Fe(0)) nanoparticles in pyridine using lithium bipyridinyl ([LiBipy]) or lithium pyridinyl ([LiPy]) is presented. FeCl₃ is used as the most simple starting material and reduced either in a [LiBipy]‐driven two‐step approach or in a [LiPy]‐driven one‐pot synthesis. High‐quality nanoparticles are obtained with uniform, spherical shape, and mean diameters of 2.9 ± 0.5 nm ([LiBipy]) or 4.1 ± 0.7 nm ([LiPy]). The as‐prepared, high purity Fe(0) nanoparticles are monocrystalline. In addition to particle characterization (high‐resolution transmission electron microscopy, scanning transmission electron microscopy, dynamic light scattering), composition and purity are examined in detail based on electron diffraction, X‐ray powder diffraction, elemental analysis, infrared spectroscopy, ⁵⁷Fe Mössbauer spectroscopy, and magnetic measurements. Due to their small size and high purity, the Fe(0) nanoparticles are highly reactive. They can be used in follow‐up reactions to obtain a variety of iron compounds, which is exemplarily shown for the transformation to iron carbide (Fe₃C) nanoparticles, the reaction with sulfur to obtain FeS nanoparticles, or the direct reaction with pentamethylcyclopentadiene to FeCp*₂ (Cp*: pentamethylcyclopentadienyl).     

Möglichkeiten und Grenzen von Beratung bei (späten) Schwangerschaftsabbrüchen

Definition of the problem Current legislative initiatives that are aiming to change the German abortion law emphasise the importance of counselling for the pregnant woman before and after a prenatal diagnosis. By stating this they are also strengthening the impact of a woman’s decision. Furthermore, several counselling structures have been suggested or established in order to support the decision-making-process of the physicians who are involved in an abortion after a prenatal diagnosis. This article addresses opportunities and limitations of counselling for the physician as well as for the pregnant woman before (late) termination of pregnancy. Arguments and conclusion Comprehensive counselling of a pregnant woman before prenatal testing and termination of pregnancy can be an effective tool to enable autonomous choices as well as to secure the rights of the unborn child. Counselling committees, established to support the certifying physician, perform a kind of hypothetical surrogate decision-making, which is difficult to legitimise, – either legally or ethically. Furthermore, they illuminate fundamental difficulties attached to the current interpretation and use of the medical indication for termination of pregnancy in Germany, which therefore should also be addressed, if a consistent revision of the abortion law is intended.     

Bioimaging of metals by laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS)

The distribution analysis of (essential, beneficial, or toxic) metals (e.g., Cu, Fe, Zn, Pb, and others), metalloids, and non‐metals in biological tissues is of key interest in life science. Over the past few years, the development and application of several imaging mass spectrometric techniques has been rapidly growing in biology and medicine. Especially, in brain research metalloproteins are in the focus of targeted therapy approaches of neurodegenerative diseases such as Alzheimer's and Parkinson's disease, or stroke, or tumor growth. Laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) using double‐focusing sector field (LA‐ICP‐SFMS) or quadrupole‐based mass spectrometers (LA‐ICP‐QMS) has been successfully applied as a powerful imaging (mapping) technique to produce quantitative images of detailed regionally specific element distributions in thin tissue sections of human or rodent brain. Imaging LA‐ICP‐QMS was also applied to investigate metal distributions in plant and animal sections to study, for example, the uptake and transport of nutrient and toxic elements or environmental contamination. The combination of imaging LA‐ICP‐MS of metals with proteomic studies using biomolecular mass spectrometry identifies metal‐containing proteins and also phosphoproteins. Metal‐containing proteins were imaged in a two‐dimensional gel after electrophoretic separation of proteins (SDS or Blue Native PAGE). Recent progress in LA‐ICP‐MS imaging as a stand‐alone technique and in combination with MALDI/ESI‐MS for selected life science applications is summarized. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:156–175, 2010     

Microstructure Evolution and Cation Interdiffusion in Thin Sm2O3 Films on CeO2 Substrates

Samaria (Sm₂O₃) thin films with a thickness of 180 nm were deposited on polycrystalline CeO₂ substrates by pulsed layer deposition to study phase formation and bulk cation interdiffusion in the Ce_1?xSm_xO_2?x/2 system after annealing at temperatures between 987°C and 1266°C. Transmission electron microscopy combined with electron diffraction and analytical techniques was applied for phase determination. The cubic fluorite and cubic bixbyite phases were observed at low and intermediate Sm concentrations. The monoclinic phase occurs only at very high Sm concentrations due to the low Ce‐solubility in Sm₂O₃. Furthermore, a cubic phase with I2₁3 structure was observed at higher Sm concentrations. Cation interdiffusion coefficients were derived from Sm concentration profiles across the Sm₂O₃/CeO₂ interface using the diffusion–couple solution of the diffusion equation. The temperature dependence of interdiffusion coefficients is well described by an Arrhenius‐type relation, which yields an activation enthalpy of 2.26 eV/atom for bulk cation interdiffusion.     

Quantitative analysis of backscattered-electron contrast in scanning electron microscopy

Backscattered-electron scanning electron microscopy (BSE-SEM) imaging is a valuable technique for materials characterisation because it provides information about the homogeneity of the material in the analysed specimen and is therefore an important technique in modern electron microscopy. However, the information contained in BSE-SEM images is up to now rarely quantitatively evaluated. The main challenge of quantitative BSE-SEM imaging is to relate the measured BSE intensity to the backscattering coefficient η and the (average) atomic number Z to derive chemical information from the BSE-SEM image. We propose a quantitative BSE-SEM method, which is based on the comparison of Monte–Carlo (MC) simulated and measured BSE intensities acquired from wedge-shaped electron-transparent specimens with known thickness profile. The new method also includes measures to improve and validate the agreement of the MC simulations with experimental data. Two different challenging samples (ZnS/Zn(O_xS_1–x)/ZnO/Si-multilayer and PTB7/PC₇₁BM-multilayer systems) are quantitatively analysed, which demonstrates the validity of the proposed method and emphasises the importance of realistic MC simulations for quantitative BSE-SEM analysis. Moreover, MC simulations can be used to optimise the imaging parameters (electron energy, detection-angle range) in advance to avoid tedious experimental trial and error optimisation. Under optimised imaging conditions pre-determined by MC simulations, the BSE-SEM technique is capable of distinguishing materials with small composition differences.     

Tocols of selected spring wheat (Triticum aestivum L.), einkorn wheat (Triticum monococcum L.) and wild emmer (Triticum dicoccum Schuebl [Schrank]) varieties

Wheat contributes significantly worldwide to antioxidant income with beneficial healthy effects. Two varieties of einkorn wheat (Triticum monococcum L. – Escana and Schwedisches Einkorn), two varieties of wild emmer [Triticum dicoccum Schuebl (Schrank)] (Rudico and Kahler Emmer) and three varieties of spring wheat (Triticum aestivum L. – Granny, Kärtner Früher and SW Kadrilj) were evaluated for tocols – tocopherols and tocotrienols by high performance liquid chromatography – electrospray ionisation tandem mass spectrometry (HPLC–ESI/MS/MS). Investigated emmer and einkorn wheat varieties have shown minor lower total tocols content in comparison with spring varieties, however significant typical levels of tocopherols and tocotrienols were found in these groups. In einkorn wheat varieties the major abundance of total tocols is represented by tocotrienols (Schwedisches Einkorn 65.0%, Escana 54.9%), in emmer wheat varieties the abundance of tocotrienols and tocopherols were similar (Rudico 48.9% of tocotrienols, Kahler Emmer 47.6%), whereas in spring bread wheat higher tocopherols (SW Kadrilj 54.5%, Kärtner Früher 60.2%, Granny 55.0%) were recorded.     

Soy extract has different effects compared with the isolated isoflavones on the proteome of homocysteine-stressed endothelial cells

Epidemiological studies suggest that soy consumption may provide a protection in the development and progression of atherosclerosis. It is under debate, however, whether the soy isoflavones or other compounds are the "active principle". As apoptosis is a driving force in the process of atherosclerosis, we tested whether a soy extract or a combination of the two predominant isoflavones genistein and daidzein, in concentrations as found in the extract, exert similar or different effects on apoptosis in EA.hy 926 endothelial cells after exposure to the endothelial stressor homocysteine. Plasma membrane disintegration and nuclear fragmentation served as relevant apoptosis markers. To assess whether the extract and the genistein/daidzein mixture differently affect cellular target proteins changed in amount by homocysteine treatment, proteome analysis was performed by two-dimensional gel-electrophoresis and peptide mass fingerprinting of regulated protein spots. Homocysteine induced apoptosis in the cells, and both extract and genistein/daidzein inhibited apoptosis to a comparable extent. Whereas the extract prevented for 10 proteins the changes in expression levels as caused by homocysteine, the genistein/daidzein mixture reversed the homocysteine effects on the proteome for 13 proteins. The cytoskeletal protein matrin 3 and a U5 snRNP-specific 40-kDa protein were the only protein entities where both extract and genistein/daidzein reversed the homocysteine-induced changes in a common way. In conclusion, our studies provide evidence that an isoflavone containing soy extract and isolated isoflavones, despite similar effects on inhibition of homocysteine-induced apoptosis in endothelial cells, affect a quite different spectrum of cellular target proteins.     

Above-ground carbon storage by urban trees in Leipzig, Germany: Analysis of patterns in a European city

Many aspects of global change, including carbon dioxide emissions, have been attributed to urban areas. On the other hand, cities have been found to provide valuable ecosystem services such as carbon storage. The aim of this study is to estimate the above-ground carbon storage in trees in the central European city of Leipzig and produce spatially explicit carbon storage maps. We used stratified random sampling across 19 land cover classes using 190 sample plots to measure carbon storage. In addition, we derived canopy cover from color-infrared orthophotos using an object-oriented approach and Random Forest machine learning. Finally, we apply an error assessment method that includes sampling error, but also uncertainty stemming from allometric equations, and that so far has only been applied to rural forests. The total above ground carbon stock of Leipzig was estimated using both land cover and canopy cover, which was more laborious than just using land cover but reduced the standard error. Canopy cover was approximately 19% of the city area. Leipzig's above-ground carbon storage was estimated to be 316,000 Mg C at 11 Mg C ha⁻¹. The distribution of carbon storage across the city showed the highest values at intermediate urbanization levels. Carbon storage in the city of Leipzig was in the lower range compared to cities in Europe, Asia and the USA, and our results indicate that great care should be taken when transferring values between cities. We provide spatially explicit and detailed maps of above-ground storage that can contribute to ecosystem services assessments.     

SMART RHESINs—Superparamagnetic Magnetite Architecture Made of Phenolic Resin Hollow Spheres Coated with Eu(III) Containing Silica Nanoparticles for Future Quantitative Magnetic Particle Imaging Applications

Magnetic particle imaging (MPI) is a powerful and rapidly growing tomographic imaging technique that allows for the non-invasive visualization of superparamagnetic nanoparticles (NPs) in living matter. Despite its potential for a wide range of applications, the intrinsic quantitative nature of MPI has not been fully exploited in biological environments. In this study, a novel NP architecture that overcomes this limitation by maintaining a virtually unchanged effective relaxation (Brownian plus Néel) even when immobilized is presented. This superparamagnetic magnetite architecture made of phenolic resin hollow spheres coated with Eu(III) containing silica nanoparticles (SMART RHESINs) was synthesized and studied. Magnetic particle spectroscopy (MPS) measurements confirm their suitability for potential MPI applications. Photobleaching studies show an unexpected photodynamic due to the fluorescence emission peak of the europium ion in combination with the phenol formaldehyde resin (PFR). Cell metabolic activity and proliferation behavior are not affected. Colocalization experiments reveal the distinct accumulation of SMART RHESINs near the Golgi apparatus. Overall, SMART RHESINs show superparamagnetic behavior and special luminescent properties without acute cytotoxicity, making them suitable for bimodal imaging probes for medical use like cancer diagnosis and treatment. SMART RHESINs have the potential to enable quantitative MPS and MPI measurements both in mobile and immobilized environments.