Die Brücke Lockwitztal – eine Revision nach Entwurf und Ausführung

The Bridge Lockwitztal, a Review of Design and Execution. In the course of the newly built federal motorway A 17, the bridge Lockwitztal crosses a wide valley in a maximum height of 64 m, with a length of 723 m. At the bottom of the valley lies a suburb of Dresden and at the valley slopes exist nature areas which have to be conserved. With the executed design, an adequate solution for the demanding situation was found. The two main spans are each 125 m. In four of the spans are situated concrete arch struts, which together with the composite superstructure and the piers form an integral frame system. The bridge shows a new way of deploying the aesthetic value of arch systems in the crossing of valleys up to now thought as not suitable for this and with the innovative construction was developed a novel link between arch systems and strutted frame systems. In the paper are discussed the essential elements of the construction and of the building processes in review after execution.     

Lipoconjugates for the noncovalent generation of microarrays in biochemical and cellular assays

The generation of microarrays by functionalization of hydrophobic glass surfaces with conjugates of triacylated lipophilic end-groups and with a peptide or hapten as a test substance is presented. Immobilization on the hydrophobic surfaces through the triacylated anchor group is fully orthogonal to the reactivity of functional groups within the test substances. The technique is therefore free of risk that reactions of these functional groups may influence the biological activity of the test compounds in screening applications. In addition, no preactivation of either the surface or the compounds is required. Reagents and substrates may be stored at ambient conditions for long periods of time. The lipoconjugates are administered from aqueous solution enabling automated nanopipetting down to spot dimensions of 100 microm across. The microstructures are stable with respect to the conditions of biochemical assays and applications in cell biology. Due to the hydrophobicity of the nonfunctionalized surfaces, standard blocking protocols used in microtiter-plate testing can be employed, thereby inhibiting nonspecific binding of assay reagents. Generation of these microstructures on hydrophobic glass slides or coverslips enables highly sensitive multichannel read-outs with high-resolution fluorescence microscopy.     

The contribution of β-carotene to vitamin A supply of humans

Populations that administer highly restrictive diets using a strong dietary regime, excluding certain types of food, might be at risk of vitamin A insufficiency, even in developed countries. Thus, provitamin A carotenoids from plants represent an additional major dietary source of vitamin A for most of the world's population. Our aim was to estimate the contribution of β-carotene to vitamin A supply in industrialized countries using available data from the literature. A total of 11 studies from 8 countries were used, representing data of 121,256 participants. Intakes of total vitamin A, provitamin A carotenoids, including β-carotene were retrieved and used to calculate the retinol activity equivalents (RAE) utilizing current conversion factors. Mean total daily dietary intake of RAE was 1083±175. The mean β-carotene intake was 3.9 mg/day. Preformed vitamin A accounts for nearly 65% of total vitamin A intake, carotenoids make up 35%. No statistical differences between men and women in total intake of retinol were observed. We conclude that a safe vitamin A intake in general cannot be reached by consuming only one component (vitamin A or β-carotene) alone, even in Western countries where animal products are commonly available.     

Sucrose transport through maltoporin mutants of Escherichia coli

Maltoporin (LamB) and sucrose porin (ScrY) reside in the bacterialouter membrane and facilitate the passive diffusion of maltodextrinsand sucrose, respectively. To gain further insight into thedeterminants of solute specificity, LamB mutants were designedto allow translocation of sucrose, which hardly translocatesthrough wild-type LamB. Three LamB mutants were studied. (a)Based on sequence and structure alignment of LamB with ScrY,two LamB triple mutants were generated (R109D, Y118D,D121F;R109N,Y118D,D121F) to mimic the ScrY constriction. The crystalstructure of the first of these mutants was determined to be3.2 Å and showed an increased ScrY-like cross-sectionexcept for D109 that protrudes into the channel. (b) Based onthis crystal structure a double mutant was generated by truncationof the two residues that obstruct the channel most in LamB (R109A,Y118A).Analysis of liposome swelling and in vivo sugar uptake demonstratedsubstantial sucrose permeation through all mutants with thedouble alanine mutant performing best. The triple mutants didnot show a well-defined binding site as indicated by sugar-inducedion current noise analysis, which can be explained by remainingsteric interference as deduced from the crystal structure. Binding,however, was observed for the double mutant that had the obstructingresidues truncated to alanines.     

Proton beam writing of microstructures in Agar gel for patterned cell growth

A rather useful prerequisite for many biological and biophysical studies, e.g., for cell-cell communication or neuronal networks, is confined cell growth on micro-structured surfaces. Solidified Agar layers have smooth surfaces which are electrically neutral and thus inhibit receptor binding and cell adhesion. For the first time, Agar microstructures have been manufactured using proton beam writing (PBW). In the irradiated Agar material the polysaccharides are split into oligosaccharides which can easily be washed off leaving Agar-free areas for cell adhesion. The beam diameter of 1 μm allows the fabrication of compartments accommodating single cells which are connected by micrometer-sized channels. Using the external beam the production process is very fast. Up to 50 Petri dishes can be produced per day which makes this technique very suitable for biological investigations which require large throughputs.     

A two species trap for chromium and rubidium atoms

Abstract

We realize a combined trap for bosonic chromium (⁵²Cr) and rubidium (⁸⁷Rb) atoms. Initial experiments focus on exploring a suitable loading scheme for the combined trap and on studies of new trap loss mechanisms originating from simultaneous trapping of two species. By comparing the trap loss from the ⁸⁷Rb magneto-optical trap (MOT) in the absence and presence of magnetically trapped ground state ⁵²Cr atoms we determine the scattering cross-section of σ _inel,RbCr = 5.0 ± 4.0 × 10^?18 m² for light-induced inelastic collisions between the two species. Studying the trap loss from the Rb magneto-optical trap induced by the Cr cooling-laser light, the photoionization cross-section of the excited 5P_3/1 state at an ionizing wavelength of 426 nm is measured to be σ _P = 1.1 ± 0.3 × 10^?21 m².     

The Role of Inflammation in Breast and Prostate Cancer Metastasis to Bone

Tumor metastasis to bone is a common event in multiple forms of malignancy. Inflammation holds essential functions in homeostasis as a defense mechanism against infections and is a strategy to repair injured tissue and to adapt to stress conditions. However, exaggerated and/or persistent (chronic) inflammation may eventually become maladaptive and evoke diseases such as autoimmunity, diabetes, inflammatory tissue damage, fibrosis, and cancer. In fact, inflammation is now considered a hallmark of malignancy with prognostic relevance. Emerging studies have revealed a central involvement of inflammation in several steps of the metastatic cascade of bone-homing tumor cells through supporting their survival, migration, invasion, and growth. The mechanisms by which inflammation favors these steps involve activation of epithelial-to-mesenchymal transition (EMT), chemokine-mediated homing of tumor cells, local activation of osteoclastogenesis, and a positive feedback amplification of the protumorigenic inflammation loop between tumor and resident cells. In this review, we summarize established and evolving concepts of inflammation-driven tumorigenesis, with a special focus on bone metastasis.     

Heavy-Water (D2O) Take-Up-Induced Lattice Expansion in the High-Temperature Proton Conductor Ba3Ca1.18Nb1.82O9−δ

Dimensional changes of the high-temperature proton conductor Ba₃Ca_1.18Nb_1.82O_9−δ, when exposed to D₂O vapor, were investigated using length-change and precision density measurements. Such information is essential for possible applications of proton conductors in solid oxide fuel cells and humidity and hydrogen sensors. A linear increase of the sample lengths with increases in the deuterium content was observed. Comparison of the present D₂O data with those that were previously obtained for H₂O showed that there was a small isotope effect in the lattice expansion. The fact that the length-change-versus-hydrogen-isotope-concentration curves were almost isotope independent supported the validity of the take-up reaction H₂O( g ) + V_Oö+ Ox_O is an ⇄ 2OH_O. In regard to the latter equation, it was found that small islands of silver, palladium, nickel, and platinum act as catalytic promoters of the reaction and lead, for given heavy-water-steam exposure conditions, to an increase of water absorption of up to 100%, when compared with samples without the catalytic surface layers.     

Capillary zone electrophoresis for gliadin separation: applications in a spelt breeding program

Gliadins of 27 European spelt [Triticum aestivum ssp. spelta (L.) Thell.] cultivars (cvs) were separated by capillary zone electrophoresis (CZE). A great amount of diversity was found within the CZE gliadin patterns of these cvs; however, only 15 had unique patterns, whereas 2 triples and 3 pairs were identical, i.e., differences were within the uncertainty of the method and environmental effects. Two of these identical pairs were attributed to mislabeling: affected were one of the two Swiss spelt cvs 'Ostar' and 'Sertel', and the German spelt cv 'Steiners Roter Tiroler'. The German cv 'Franckenkorn' showed considerable similarity with the Belgian cv 'Rouquin'. CZE gliadin patterns of 12 modern German bread wheat cvs were distinctly different from those of spelt cvs selected from old land varieties like the Swiss cv 'Oberkulmer Rotkorn'. In the gliadin patterns of 11 spelt cvs, bread wheat elements were found. 7 of the 24 cvs not mislabeled are known to be progeny of wheat/spelt crosses, 4 cvs are described as pure spelt, and the pedigrees of 13 are unknown. Wheat elements were spotted in only 4 of the 7 wheat/spelt crosses and in none of the 4 pure spelt cvs. The results suggest that crossing spelt with modern wheat may be, but is not necessarily, reflected in the gliadin pattern.