Ab initio and nuclear inelastic scattering studies of Fe3_3Si/GaAs heterostructures

The structure and dynamical properties of the Fe$_3$Si/GaAs(001) interface are investigated by density functional theory and nuclear inelastic scattering measurements. The stability of four different atomic configurations of the Fe$_3$Si/GaAs multilayers is analyzed by calculating the formation energies and phonon dispersion curves. The differences in charge density, magnetization, and electronic density of states between the configurations are examined. Our calculations unveil that magnetic moments of the Fe atoms tend to align in a plane parallel to the interface, along the [110] direction of the Fe$_3$Si crystallographic unit cell. In some configurations, the spin polarization of interface layers is larger than that of bulk Fe$_3$Si. The effect of the interface on element-specific and layer-resolved phonon density of states is discussed. The Fe-partial phonon density of states measured for the Fe$_3$Si layer thickness of three monolayers is compared with theoretical results obtained for each interface atomic configuration. The best agreement is found for one of the configurations with a mixed Fe-Si interface layer, which reproduces the anomalous enhancement of the phonon density of states below 10 meVComment: 14 pages, 9 figures, 4 table

Geschlechtergerechte Sprache in der Wissenschaft : Gebrauch und Motivation

Seit den 1970ern ist geschlechtergerechte Sprache (ggS) im deutschen Sprachraum ein Thema. Die Diskussionen wandelten sich dabei stark. Ging es erst vorrangig um Sichtbarkeit von Frauen, stehen seit den 1990ern Heteronormativitätskritik und die Suche nach inklusiven Sprachformen im Vordergrund. Die vertretenen Positionen haben sich nicht abgelöst, sondern ergänzen sich teilweise oder stehen nebeneinander (in Konflikt). Trotz einer gewissen Institutionalisierung hat ggS ins wissenschaftliche Register kaum Aufnahme gefunden. Dabei ist Sprachwandel besonders wirksam, wenn statushohe Gruppen ihn vorleben. Zudem ist ggS exakter als ‚generische‘ Maskulina. Über ihren Gebrauch von ggS sowie ihre Präferenz bestimmter Formen, bzw. Hinderungsgründe für deren Verwendung, wurden in einer Online-Erhebung 290 Wissenschaftler_innen aus Geschlechterforschung und Medizin befragt. Die Ergebnisse wurden deskriptiv ausgewertet und dann hinsichtlich geschlechtertheoretischer Überlegungen reflektiert. In the 1970s, gender-fair language became a much debated topic in Germany. Since then, the motiva- tion for its use, as well as the linguistic forms used to promote it, have changed considerably. Initially, visibility of women was pursued. Since the 1990s, a critique of heteronormativity emerged, and a ten- dency towards more inclusive linguistic forms grew. To this day, gender-fair language is noticeably absent in most academic texts. This is surprising, as gender-fair language is more precise than the use of generic masculine forms. Also, the language use by high-status groups, such as academics, tends to function as a role model. To explore this issue, 290 academics from the areas of gender studies and medicine were consulted in an online survey about their use of gender-fair language, their preferences for certain options, and possible impediments. After a descriptive analysis of the findings, they were discussed in a gender-theoretical context and used for an outlook into future developments

Lattice dynamics of endotaxial silicide nanowires

Self-organized silicide nanowires are considered as main building blocks of future nanoelectronics and have been intensively investigated. In nanostructures, the lattice vibrational waves (phonons) deviate drastically from those in bulk crystals, which gives rise to anomalies in thermodynamic, elastic, electronic, and magnetic properties. Hence, a thorough understanding of the physical properties of these materials requires a comprehensive investigation of the lattice dynamics as a function of the nanowire size. We performed a systematic lattice dynamics study of endotaxial FeSi$_2$ nanowires, forming the metastable, surface-stabilized $\alpha$-phase, which are in-plane embedded into the Si(110) surface. The average widths of the nanowires ranged from 24 to 3 nm, their lengths ranged from several $\mu$m to about 100 nm. The Fe-partial phonon density of states, obtained by nuclear inelastic scattering, exhibits a broadening of the spectral features with decreasing nanowire width. The experimental data obtained along and across the nanowires unveiled a pronounced vibrational anisotropy that originates from the specific orientation of the tetragonal $\alpha$-FeSi$_2$ unit cell on the Si(110) surface. The results from first-principles calculations are fully consistent with the experimental data and allow for a comprehensive understanding of the lattice dynamics of endotaxial silicide nanowires.Comment: 9 pages, 7 figures, 3 table

Collagen fleeces do not improve colonic anastomotic strength but increase bowel obstructions in an experimental rat model

To investigate whether a collagen fleece kept in place by fibrin glue might seal off a colorectal anastomosis, provide reinforcement, and subsequently improve anastomotic healing. Wistar rats underwent a 1-cm left-sided colonic resection followed by a 4-suture end-to-end anastomosis. They were then randomly assigned to one of three treatment groups: no additional intervention (control, n = 20), the anastomosis covered with fibrin glue (fibrin glue, n = 20), the anastomosis covered with a collagen fleece, kept in place with fibrin glue (collagen fleece, n = 21). At either 3 or 7 days follow-up, anastomotic bursting pressure was measured and tissue was obtained for histology and collagen content assessment after which animals were sacrificed. Three rats in the control (15%), three in the fibrin glue (15%), and one in the collagen group (4.8%) died due to anastomotic complications (P = 0.497). Anastomotic bursting pressures were not significantly different between groups at 3 and 7 days follow-up (P = 0.659 and P = 0.427, respectively). However, bowel obstructions occurred significantly more often in the collagen group compared to the control group (14/21 vs. 3/20, P = 0.003). Collagen contents were not different between groups, but histology showed a more severe inflammation in the collagen group compared to the other groups at both 3 and 7 days follow-up. A collagen fleece kept in place by fibrin glue does not improve healing of colonic anastomoses in rats. Moreover, this technique induces significantly more bowel obstructions in rats, warranting further study before being translated to a clinical settin

Deutsch-Franzoesische Kooperation auf dem Gebiet spurgebundener Schnellbahnsysteme. Anhang M - zur Konzeption und Entwicklung eines zukuenftigen universellen europaeischen Betriebsleitsystems Abschlussbericht

SIGLEAvailable from TIB Hannover: DtF QN1(63,53) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman