Variations in the polyphenol content of seeds of field grown Amaranthus genotypes

In a cultivation experiment 18 different Amaranthus genotypes were cultivated in parallel in Argentina, Mexico, Spain and two different locations in the Czech Republic. The ripe seeds were analysed for their content of 11 polyphenols and the variations among genotype, species and location were analysed by principal component analysis (PCA). The flavonoid, rutin, exhibited large variations with varying environmental conditions whereas the flavonoid, nicotiflorin, was affected less. Amaranthus hypochondriacus displayed the most stable content of polyphenols with a high end content of flavonoids. The variations between location/environmental condition were primarily described by the variations in the content of p-coumaric acid and protocatechuic acid in the seed samples.     

Thermo-responsive cell culture carriers based on poly(vinyl methyl ether)—the effect of biomolecular ligands to balance cell adhesion and stimulated detachment

Two established material systems for thermally stimulated detachment of adherent cells were combined in a cross-linked polymer blend to merge favorable properties. Through this approach poly(N-isopropylacrylamide) (PNiPAAm) with its superior switching characteristic was paired with a poly(vinyl methyl ether)-based composition that allows adjusting physico-chemical and biomolecular properties in a wide range. Beyond pure PNiPAAm, the proposed thermo-responsive coating provides thickness, stiffness and swelling behavior, as well as an apposite density of reactive sites for biomolecular functionalization, as effective tuning parameters to meet specific requirements of a particular cell type regarding initial adhesion and ease of detachment. To illustrate the strength of this approach, the novel cell culture carrier was applied to generate transplantable sheets of human corneal endothelial cells (HCEC). Sheets were grown, detached, and transferred onto planar targets. Cell morphology, viability and functionality were analyzed by immunocytochemistry and determination of transepithelial electrical resistance (TEER) before and after sheet detachment and transfer. HCEC layers showed regular morphology with appropriate TEER. Cells were positive for function-associated marker proteins ZO-1, Na⁺/K⁺-ATPase, and paxillin, and extracellular matrix proteins fibronectin, laminin and collagen type IV before and after transfer. Sheet detachment and transfer did not impair cell viability. Subsequently, a potential application in ophthalmology was demonstrated by transplantation onto de-endothelialized porcine corneas in vitro. The novel thermo-responsive cell culture carrier facilitates the generation and transfer of functional HCEC sheets. This paves the way to generate tissue engineered human corneal endothelium as an alternative transplant source for endothelial keratoplasty.     

Cellular uptake and cell-to-cell transfer of polyelectrolyte microcapsules within a triple co-culture system representing parts of the respiratory tract

Polyelectrolyte multilayer microcapsules around 3.4 micrometers in diameter were added to epithelial cells, monocyte-derived macrophages, and dendritic cells in vitro and their uptake kinetics were quantified. All three cell types were combined in a triple co-culture model, mimicking the human epithelial alveolar barrier. Hereby, macrophages were separated in a three-dimensional model from dendritic cells by a monolayer of epithelial cells. While passing of small nanoparticles has been demonstrated from macrophages to dendritic cells across the epithelial barrier in previous studies, for the micrometer-sized capsules, this process could not be observed in a significant amount. Thus, this barrier is a limiting factor for cell-to-cell transfer of micrometer-sized particles.     

The significance of flood regimes for carabid beetle and spider communities in riparian habitats—a comparison of three major rivers in Germany

River regulation and water management practices have led to alteration of the flood regimes of all large rivers in Germany. To investigate its influence on the terrestrial arthropod fauna, a comparative study was carried out on the distribution of ground beetles (Carabidae) and spiders (Araneae) at the potamal sections of three large rivers in northern Germany, the Rivers Weser, Elbe and Oder. The three rivers differ markedly in their flood dynamics, mainly owing to weirs and polder management practices, but also owing to natural conditions in their headwaters. In total, 45 sites were examined with a total capture of 46 727 carabid beetles and 38 066 adult spiders, representing 178 and 209 species, respectively. Using multivariate TWINSPAN analyses we found that the ground beetle species assemblages clearly varied according to the different flood regimes. By contrast, the spiders differentiate well between sites of different habitat structure. In particular, the river margins hosted a specialized carabid fauna, and the alluvial Quercus–Ulmus forests were habitat for some rare and endangered carabid and spider species. Whereas the fauna of the strongly regulated River Weser was impoverished regarding stenotopic hygrophilous species, the fauna of the more natural Rivers Elbe and Oder depended very much on the duration and timing of the flooding, as well as on the local micro‐topographical situation. It is concluded that low lying areas behind dykes of the Elbe, or in polders of the Oder, which become frequently inundated by river or ground water, are extremely valuable for invertebrate conservation. The data suggest that careful polder management may support suitable habitat creation for riparian species, as long as the inundation scheme corresponds to natural flood dynamics conditions. Copyright © 2002 John Wiley & Sons, Ltd.     

A rapid benchtop NMR method for determination of droplet size distributions in food emulsions

The determination of water and oil droplet size distributions in food emulsions by low‐field NMR has the advantage of a simple and non‐perturbing sample preparation. Furthermore, NMR performs very well with respect to precision. The current implementation on most benchtop NMR spectrometers deploys a variation of gradient duration and requires continuous corrections for gradient imbalances, thus making the whole procedure a time‐consuming one. By using variation of gradient strength and further stretching the capability of commercial benchtop NMR spectrometers, both water and oil droplet sizes can be measured in a more rapid manner, typically two to three times faster. The measured droplet size distributions are equivalent to those assessed by the current (slow) method, for both O/W and W/O emulsions. Furthermore, the rapid method shows a good performance with respect to precision. In addition, the method is able to determine droplet sizes in samples with much smaller amounts of dispersed phase.     

Timber Beams Strengthened with GFRP Bars: Development and Applications

Repair and rehabilitation of infrastructure is becoming increasingly important for bridges due to material deterioration and limited capacity to accommodate current load levels. An experimental program was undertaken to study the flexural behavior of creosote-treated sawn Douglas fir timber beams strengthened with glass fiber-reinforced polymer (GFRP) bars. Twenty-two half-scale and four full-scale timber beams strengthened with GFRP were tested to failure. The percent reinforcement ratios were between 0.27 and 0.82%. Additional unreinforced timber beams were tested as control specimens. The results have shown that using the proposed experimental technique changed the failure mode from brittle tension to compression failure, and flexural strength increased by 18 to 46%. Research findings indicate the use of near-surface GFRP bars overcomes the effect of local defects in the timber and enhances the bending strength of the members. Based on the experimental results, an analytical model is proposed to predict the flexural capacity of both unreinforced and GFRP-reinforced timber beams. The article also reviews implementation of the proposed technique for strengthening a timber bridge near Winnipeg, Manitoba, Canada.     

Interest, learning, and the psychological processes that mediate their relationship.

Although influences of interest on learning are well documented, mediating processes have not been clarified. The authors investigated how individual and situational interest factors contribute to topic interest and text learning. Traditional self-report measures were combined with novel interactive computerized methods of recording cognitive and affective reactions to science and popular culture texts, monitoring their development in real time. Australian and Canadian students read 4 expository texts. Both individual interest variables and specific text titles influenced topic interest. Examination of processes predictive of text learning indicated that topic interest was related to affective response, affect to persistence, and persistence to learning. Combining self-rating scales with dynamic measures of student activities provided new insight into how interest influences learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)