50 research outputs found
Kairo, Ägypten. Restaurierungsprojekt Glasnegative im Center of Documentation, Zitadelle Kairo. Die Arbeiten der Jahre 2015 bis 2017
The Photographic Archive at the Citadel in Old Cairo / Egypt comprises ca. 14,000 objects, mainly silver gelatine glass negatives and acetate sheet film negatives. Since 2002 the DAI Cairo is – thanks to the support by the German Foreign Ministry – involved in a restauration and training program which aims at helping to secure, safely store, and conserve the glass negatives and at training of local inspectors in order to create local conservation and restauration capacities
Reactivity of Isocyanate-Functionalized Lignins: A Key Factor for the Preparation of Lignin-Based Polyurethanes
Using isocyanate-functionalized Kraft lignin as a reactive macromonomer for the preparation of polyurethane foams by a prepolymer technique is a well-known strategy to incorporate the biomacromolecule into a higher value polymer material. However, as of today the mechanical properties of the resulting materials are still insufficient for a number of possible applications. One reason for this limitation is that the reaction pathway and the morphological arrangement of such foams is of uttermost complexity and depends on a large number of influencing material-intrinsic factors. One important parameter is the reactivity of the functionalized lignin, which has a great impact on the interphase reaction kinetics and thus, on the geometry and mechanical properties of the resulting polyurethane foams. The reactivity is implied, amongst others, by the electron affinity of the isocyanate moiety. Herein, we investigate the reactivity of Kraft lignin modified with different commercially used isocyanates in the reaction with conventional polyols. Therefore, differently reactive prepolymers were synthesized, characterized and polyurethane foams were prepared thereof by using these compounds and the foam formation kinetics, morphological as well as mechanical properties were investigated. Finally, the results were supported by quantum mechanical calculations of the electron affinities of representative model compounds for the lignin-based prepolymers. This work gives rise to a better understanding of the effect of the reactivity and isocyanate structure linked to Kraft lignin on the polyurethane formation and enables rational choice of the isocyanate for pre-functionalization of lignin to prepare materials with better mechanical performance
Understandings of scientific inquiry: an international collaborative investigation of seventh grade students
Although understandings of scientific inquiry (as opposed to conducting inquiry) is included in science
education reform documents around the world, little is known about what students have learned about inquiry
during their primary school years. This is partially due to the lack of any assessment instrument to measure
understandings about scientific inquiry. However, a valid and reliable assessment has recently been developed
and published, Views About Scientific Inquiry (VASI) (Lederman J. et. al., 2014). The purpose of this large
scale (i.e., 19 countries spanning six continents and including 2,960 students) international project was to get
the first baseline data on what grade students have learned. The participating countries were: Australia,
Brazil, Canada, Chile, China, Egypt, England, Finland, France, Germany, Israel, New Zealand, Nigeria, South
Africa, Spain, Sweden, United States, Taiwan, and Turkey. In many countries, science is not formally taught
until middle school, which is the rationale for choosing seventh grade students for this investigation. This
baseline data will simultaneously provide information on what, if anything, students learn about inquiry in
primary school, as well as their beginning knowledge as they enter secondary school
“I do not know if Mum knew what was going on:Social reproduction in boarding schools in Soviet Lapland
Edge states in a two-dimensional honeycomb lattice of massive magnetic skyrmions
We study the collective dynamics of a two-dimensional honeycomb lattice of
magnetic skyrmions. By performing large-scale micromagnetic simulations, we
find multiple chiral and non-chiral edge modes of skyrmion oscillations in the
lattice. The non-chiral edge states are due to the Tamm-Shockley mechanism,
while the chiral ones are topologically protected against structure defects and
hold different handednesses depending on the mode frequency. To interpret the
emerging multiband nature of the chiral edge states, we generalize the massless
Thiele's equation by including a second-order inertial term of skyrmion mass as
well as a third-order non-Newtonian gyroscopic term, which allows us to model
the band structure of skrymion oscillations. Theoretical results compare well
with numerical simulations. Our findings uncover the importance of high order
effects in strongly coupled skyrmions and are helpful for designing novel
topological devices.Comment: 6 pages,4 figures,accepted by Physical Review B as a Rapid
Communicatio
DNA methylation signatures of aggression and closely related constructs : A meta-analysis of epigenome-wide studies across the lifespan
DNA methylation profiles of aggressive behavior may capture lifetime cumulative effects of genetic, stochastic, and environmental influences associated with aggression. Here, we report the first large meta-analysis of epigenome-wide association studies (EWAS) of aggressive behavior (N = 15,324 participants). In peripheral blood samples of 14,434 participants from 18 cohorts with mean ages ranging from 7 to 68 years, 13 methylation sites were significantly associated with aggression (alpha = 1.2 x 10(-7); Bonferroni correction). In cord blood samples of 2425 children from five cohorts with aggression assessed at mean ages ranging from 4 to 7 years, 83% of these sites showed the same direction of association with childhood aggression (r = 0.74, p = 0.006) but no epigenome-wide significant sites were found. Top-sites (48 at a false discovery rate of 5% in the peripheral blood meta-analysis or in a combined meta-analysis of peripheral blood and cord blood) have been associated with chemical exposures, smoking, cognition, metabolic traits, and genetic variation (mQTLs). Three genes whose expression levels were associated with top-sites were previously linked to schizophrenia and general risk tolerance. At six CpGs, DNA methylation variation in blood mirrors variation in the brain. On average 44% (range = 3-82%) of the aggression-methylation association was explained by current and former smoking and BMI. These findings point at loci that are sensitive to chemical exposures with potential implications for neuronal functions. We hope these results to be a starting point for studies leading to applications as peripheral biomarkers and to reveal causal relationships with aggression and related traits.Peer reviewe
DNA methylation signatures of aggression and closely related constructs: A meta-analysis of epigenome-wide studies across the lifespan
DNA methylation profiles of aggressive behavior may capture lifetime cumulative effects of genetic, stochastic, and environmental influences associated with aggression. Here, we report the first large meta-analysis of epigenome-wide association studies (EWAS) of aggressive behavior (N = 15,324 participants). In peripheral blood samples of 14,434 participants from 18 cohorts with mean ages ranging from 7 to 68 years, 13 methylation sites were significantly associated with aggression (alpha = 1.2 × 10-7; Bonferroni correction). In cord blood samples of 2425 children from five cohorts with aggression assessed at mean ages ranging from 4 to 7 years, 83% of these sites showed the same direction of association with childhood aggression (r = 0.74, p = 0.006) but no epigenome-wide significant sites were found. Top-sites (48 at a false discovery rate of 5% in the peripheral blood meta-analysis or in a combined meta-analysis of peripheral blood and cord blood) have been associated with chemical exposures, smoking, cognition, metabolic traits, and genetic variation (mQTLs). Three genes whose expression levels were associated with top-sites were previously linked to schizophrenia and general risk tolerance. At six CpGs, DNA methylation variation in blood mirrors variation in the brain. On average 44% (range = 3-82%) of the aggression-methylation association was explained by current and former smoking and BMI. These findings point at loci that are sensitive to chemical exposures with potential implications for neuronal functions. We hope these results to be a starting point for studies leading to applications as peripheral biomarkers and to reveal causal relationships with aggression and related traits.</p
Naturwissenschaftliche Kompetenzen entwickeln: Kompetenzraster im naturwissenschaftlichen Unterricht
Naturwissenschaftliche Kompetenzen entwickeln: Kompetenzraster im naturwissenschaftlichen Unterricht
sj-docx-1-tpx-10.1177_01926233231164097 – Supplemental material for Investigation of the Proliferative Potential of FGF21 or FGF19 in Liver-Specific FGFR4-Deficient Mice
Supplemental material, sj-docx-1-tpx-10.1177_01926233231164097 for Investigation of the Proliferative Potential of FGF21 or FGF19 in Liver-Specific FGFR4-Deficient Mice by Kerstin Wäse, Thomas Bartels, Uwe Schwahn and Mostafa Kabiri in Toxicologic Pathology</p