Small-angle neutron scattering of long-wavelength magnetic modulations in reduced sample dimensions.

Magnetic small-angle neutron scattering (SANS) is ideally suited to providing direct reciprocal-space information on long-wavelength magnetic modulations, such as helicoids, solitons, merons or skyrmions. SANS of such structures in thin films or micro-structured bulk materials is strongly limited by the tiny scattering volume vis a vis the prohibitively high background scattering by the substrate and support structures. Considering near-surface scattering just above the critical angle of reflection, where unwanted signal contributions due to substrate or support structures become very small, it is established that the scattering patterns of the helical, conical, skyrmion lattice and fluctuation-disordered phases in a polished bulk sample of MnSi are equivalent for conventional transmission and near-surface SANS geometries. This motivates the prediction of a complete repository of scattering patterns expected for thin films in the near-surface SANS geometry for each orientation of the magnetic order with respect to the scattering plane.

Small-angle neutron scattering applied to low-dose neutron-irradiated Fe-Cr alloys and ferritic martensitic steel Eurofer97.

Ferritic/martensitic (F/M) Fe-Cr-based steels are candidates for applications in nuclear fission and fusion. Previous experimental results for neutron-irradiated binary Fe-Cr alloys and high-dose neutron-irradiated F/M steels contributed greatly to the understanding of the irradiation behaviour of these groups of materials. However, some details still need to be addressed. Such gaps are related to the effect of secondary alloying and impurity elements, such as Ni and Si, as well as the dose dependence at lower neutron doses [e.g. in the range 0.1-1 displacements per atom (dpa)]. This input is essential, for example, for multiscale modelling of irradiation effects or the evaluation of nuclear fission or fusion components at the first stages of operation. Using small-angle neutron scattering, three issues are addressed: (1) the effect of Cr undersaturation (5% Cr) and supersaturation (14% Cr) on the formation of irradiation-induced solute atom clusters/precipitates in low-dose neutron-irradiated Fe-Cr alloys in the presence of intentionally added levels of Ni, Si and P; (2) the effect of irradiation temperature (290°C versus 450°C); and (3) the effect of neutron dose in the range 0.06-0.6 dpa on the irradiation response of the reduced-activation F/M 9%Cr steel Eurofer97. The irradiation-enhanced formation of Cr-rich α'-phase particles was found to be the dominant effect for supersaturated Fe-14Cr-NiSiP at both irradiation temperatures. In contrast, α' formation is impossible in Fe-5Cr-NiSiP, for which the pronounced irradiation effects observed at 0.1 dpa are mainly attributed to added Ni, Si and P. Finally, Eurofer97 exhibits an exceptionally weak irradiation effect at low neutron doses, the reasons for which are also considered.

[The New Federal Fiscal Equalisation System 2020: First Results and Evaluation]. / Der neue Finanzausgleich zwischen Bund und Ländern: erste Ergebnisse und Bewertungen.

The new Federal Fiscal Equalization System became effective on 1 January, 2020. While all public budgets in the federal system of Germany were faced with high decreases in revenues caused by the measures to fight the impacts of the COVID-19 pandemic in 2020, a first evaluation shows that the differences to the old system are rather marginal. The focus now lies on the vertical distribution of the value-added tax, whereas for the fiscal capacity equalisation only revenue of the Laender are used as before. In fact, the supplementary federal grants, the federal grants for special needs and very critical new federal grants are still problematic and a strong signal for centralisation.

Multiphase magnetism in Yb2Ti2O7.

We use neutron scattering to show that ferromagnetism and antiferromagnetism coexist in the low T state of the pyrochlore quantum magnet [Formula: see text] While magnetic Bragg peaks evidence long-range static ferromagnetic order, inelastic scattering shows that short-range correlated antiferromagnetism is also present. Small-angle neutron scattering provides direct evidence for mesoscale magnetic structure that we associate with metastable antiferromagnetism. Classical Monte Carlo simulations based on exchange interactions inferred from [Formula: see text]-oriented high-field spin wave measurements confirm that antiferromagnetism is metastable within the otherwise ferromagnetic ground state. The apparent lack of coherent spin wave excitations and strong sensitivity to quenched disorder characterizing [Formula: see text] is a consequence of this multiphase magnetism.

Liquid release as a source of potential drug exposure during the handling of intravenous infusions in nursing.

PURPOSE: This study aims at experimentally determining the incidence and extent of liquid releases onto the operator's hands and into the work environment during common nursing operations involving infusions. METHODS: A sequence of operations related to the preparation and administration of infusions was conducted by three subjects for 15 times each using fluorescein marked infusion solutions and two different infusion sets (standard set vs. safety-optimized set). Unintended release of liquid was quantified by glove and surface wipe sampling and HPLC/FD analysis of the samples. Operations concerning the disposal of infusions were also part of the study. RESULTS: In over 90% of the simulations, a release of infusion solution was observed in a standard workflow, comprising priming and decapping the infusion set, connecting it to a peripheral intravenous (IV) cannula, and detaching it again. Based on median values (229 vs. 26 µl), the release of infusion solution was about ninefold higher when using the non-optimized standard infusion set. During decapping, a hand contamination was found in a majority of cases. CONCLUSIONS: The handling of infusions may involve a risk of nurses' exposure to active agents by release of infusion solution into the work environment. According to our results with different infusion sets, exposure risks can be reduced technically and by appropriate handling. Nevertheless, hand contaminations found for both sets emphasize the necessity for additional measures such as more consistent use of protective gloves.

Magnetic field-dependent spin structures of nanocrystalline holmium.

The results are reported of magnetic field-dependent neutron diffraction experiments on polycrystalline inert-gas condensed holmium with a nanometre crystallite size (D = 33 nm). At T = 50 K, no evidence is found for the existence of helifan(3/2) or helifan(2) structures for the nanocrystalline sample, in contrast with results reported in the literature for the single crystal. Instead, when the applied field H is increased, the helix pattern transforms progressively, most likely into a fan structure. It is the component of H which acts on the basal-plane spins of a given nanocrystallite that drives the disappearance of the helix; for nanocrystalline Ho, this field is about 1.3 T, and it is related to a characteristic kink in the virgin magnetization curve. For a coarse-grained Ho sample, concomitant with the destruction of the helix phase, the emergence of an unusual angular anisotropy (streak pattern) and the appearance of novel spin structures are observed.

Application and assessment of a regular environmental monitoring of the antineoplastic drug contamination level in pharmacies - the MEWIP project.

A large-scale study was carried out in order to determine the contamination level of antineoplastic drugs in pharmacies and to investigate the suitability and effects of wipe sample monitoring at regular intervals. A specific study design was developed. The 130 participating pharmacies were divided into a study and a control group, carrying out five and two wipe sampling cycles, respectively. The work practice was analyzed using questionnaires to identify factors that influence the contamination level. From 1269 wipe samples, 774 (61%) were contaminated with at least one of the analyzed cytotoxic drugs: cyclophosphamide, docetaxel, etoposide, 5-fluorouracil, gemcitabine, ifosfamide, methotrexate, and paclitaxel. A significant decrease of the contamination with cyclophosphamide and 5-fluorouracil was observed in the study group. The Monitoring-Effect Study of Wipe Sampling in Pharmacies method has proven to be a reliable and affordable tool for contamination control. Based on the 90th percentile of the contamination values, a substance-independent performance-based guidance value of 0.1ng cm(-2) has been derived.

Encapsulation of protein in silica matrices: structural evolution on the molecular and nanoscales.

The immobilization of biological species such as proteins and enzymes in sol-gel hosts is currently an area of intense research activity. However, the majority of these studies have been directed toward investigating the biological activity or physicochemical properties of the encapsulated species, with much less attention having been directed toward the effect of proteins on the structural evolution of the sol-gel matrix. This study investigates the structural evolution of sol-gel matrices in the presence of a model protein, bovine serum albumin (BSA). The sol-gel matrices were produced via the NaF-catalyzed hydrolysis of a mixture of tetramethyoxysilane (TMOS) and methyltrimethoxysilane (MTMS), yielding nanohybrid matrices with controlled pore sizes, pore volumes, and surface chemistry. The structural evolution of the matrix was investigated using a complementary suite of techniques, including solid-state (29)Si NMR, FTIR, SANS contrast variation, and N(2) sorption. A novel approach was developed to model the SANS data, to extract key structural parameters. The results indicated that the structural evolution of the matrices was modulated by a series of complex interactions between the enzyme and the evolving sol-gel nanohybrid: On the molecular scale, increasing BSA content led to an associated increase in both the abundance of linear Si-O-Si species (FTIR) and the Qn network connectivity ((29)Si NMR). However, only minor changes in the connectivity of the evolving Tn network were evident with varying BSA content. The selective role of the protein in these systems, where the approach of the methylated monomer to the vicinity of the protein's surface is presumably impeded by the hydrophobicity of the monomer, will be discussed. On the nanoscale, N(2) sorption data were consistent with an initial increase in the mesopore volume and surface area at low BSA loadings, followed by a subsequent monotonic decrease with increasing BSA content. In contrast, no such trends were evident in the in situ SANS data obtained from these samples, suggesting that modulation of the evolving network structure of the silica matrix by BSA during condensation prevents collapse of the nanoscale gel structure during freeze-drying. This latter comparison reflects the important role of in situ techniques such as small angle scattering (which can be used to study both open and closed porosity and probe nanostructure on length scales from approximately 1 nm to >100 nm) in investigating such complex, multicomponent systems, and techniques for modeling such data in sol-gel systems will be discussed.

Structure of organic-inorganic nanohybrids incorporating titanium(IV) oxoalkoxyacylate nanoclusters: a SANS study.

The small angle neutron scattering (SANS) technique was used to investigate the structure of nanohybrids consisting of a poly(methylmethacrylate) (PMMA) and one of two types of titanium(IV) nanoclusters. Cluster 1, [Ti6O4](OC2H5)8(CH2=CCH3COO)8, with polymerizable MMA ligands, formed covalent bonds with the polymer chains during the copolymerization, whereas cluster 2, [Ti6O4](OC2H5)8(CH3COO)8, had no polymerizable linkers and was blended into the polymeric matrix purely as a filler. In this study, SANS with contrast variation was used to investigate the size, shape and aggregation of the clusters in the hybrid materials, and their effect on the structure of the matrix. A polydispersed core-diffusion zone model was employed to explain the scattering contribution from the titanium clusters in both nanohybrid materials. No significant differences between the structures of the two nanohybrids were found. The fitted models suggest that the interface region between the cluster and matrix (the diffusion zone) is heavily occupied by the PMMA chains; however, they do not penetrate into the core region (titanium cluster).