An aptly positioned azido group in the spacer of a protein cross-linker for facile mapping of lysines in close proximity

Cross-links between amino acid residues in close proximity can provide distance constraints for the validation of models of the 3D structure proteins. The mapping of cross-links by the identification of linked peptides in proteolytic digests is facilitated by cleavable cross-linkers that enable isolation of the cleavage products while preserving information about the linkage. We present an amine-specific cross-linker, bis(succinimidyl)-3-azidomethyl glutarate (BAMG), that fulfils these requirements. Two parallel reaction pathways are induced by tris(carboxyethyl)phosphine (TCEP) in cross-linked peptides from BAMG-treated cytochrome c. One pathway leads to cleavage of the cross-linked species, while in the other the azido group of BAMG is reduced to an amino group without cleavage. Cross-linked peptides and peptides modified by partially hydrolysed BAMG yield distinct sets of TCEP-induced reaction products. These can be isolated by reversed-phase diagonal chromatography and identified by mass spectrometry to reveal the identity of the parent compounds. The ease with which cross-link-derived reaction products can be isolated and identified indicates that the mapping of cross-links in complex biological assemblies and mixtures of protein complexes might become feasible in the near future.     

Infrared light emission from porous silicon

Very intense broad sub-bandgap infrared (IR) light emission around 1,550 nm was observed on porous silicon by photoluminescence (PL) measurements. The integrated intensity of the IR signal is two orders of magnitude higher than that of the band–band emission in Cz silicon. PL measurements with the sample immersed in different media, e.g., in HF and H₂O₂, confirmed that the broad IR band originates from the Si/SiO _x interface. Electroluminescence spectroscopy was carried out on a porous silicon p–n junction sample contacted with indium-tin oxide. The IR band was detected at room temperature at both forward and reverse bias. The results indicate that radiative recombination through interface states is very efficient at room temperature.     

Die neue Ruhrbrücke in Wetter – Eine Stahlverbundbrücke mit luftdicht verschweißten Kästen

Von Mai 2008 bis Dezember 2010 wurde in Wetter eine neue Ruhrbrücke gebaut. Die exponierte Lage des Bauwerkes im Ruhrtal mit der Nähe zur Stadt Wetter begründete entsprechende Ansprüche an eine ausgewogene Gestaltung. Im Rahmen der Vorplanung wurden unter Beteiligung eines Architekturbüros zunächst umfangreiche Studien zur Auswahl eines geeigneten Brückensystems entwickelt. Der weiteren Planung und der Bauausführung zugrunde gelegt wurde eine etwa 361 m lange Deckbrücke in Stahlverbundbauweise mit luftdicht verschweißten Stahlkästen, mit einer maximalen Stützweite von fast 84 m und einer etwa 9 m hohen Voute über dem Pfeiler am Ruhrufer. Die Voute wurde durch Druckstreben aufgelöst und die Konstruktion dadurch gegliedert. Im Bereich der durch eine senkrechte Strukturschalung gestalteten Pfeiler wurde der Brückenüberbau parallelgurtig ausgebildet. The new Ruhr Bridge in Wetter, Germany – An air‐proof welded steel box girders. From May 2008 to December 2010 a new bridge over the Ruhr River was built in Wetter in Germany. The exposed location of the bridge over the Ruhr valley close to the city of Wetter requires a deliberate designed structure. Within the preliminary plannings, comprehensive studies about reasonable bridge construction systems were carried out, supported by an architecture office. Planned and realised has been a 361 m long bridge with air‐proof welded steel box girders and a concrete deck. The maximum span is nearly 84 m and the inclined haunch above the pier is about 9 m high. The inclined haunch has been formed with two diagonal struts to dissolve the construction. In the area of the vertical structured piers outside the Ruhr the bridge superstructure has been constructed with parallel chords.     

Activation of Humoral Immunity during the Pathogenesis of Experimental Chronic Lung Allograft Dysfunction

Alloreactive and autoreactive antibodies have been associated with the development of chronic lung allograft dysfunction (CLAD), but their pathogenic role is disputed. Orthotopic left lung transplantation was performed in the Fischer-344 to Lewis rat strain combination followed by the application of ciclosporine for 10 days. Four weeks after transplantation, lipopolysaccharide (LPS) was instilled into the trachea. Lungs were harvested before (postoperative day 28) and after LPS application (postoperative days 29, 33, 40, and 90) for histopathological, immunohistochemical, and Western blot analyses. Recipient serum was collected to investigate circulating antibodies. Lung allografts were more strongly infiltrated by B cells and deposits of immunoglobulin G and M were more prominent in allografts compared to right native lungs or isografts and increased in response to LPS instillation. LPS induced the secretion of autoreactive antibodies into the circulation of allograft and isograft recipients, while alloreactive antibodies were only rarely detected. Infiltration of B cells and accumulation of immunoglobulin, which is observed in allografts treated with LPS but not isografts or native lungs, might contribute to the pathogenesis of experimental CLAD. However, the LPS-induced appearance of circulating autoreactive antibodies does not seem to be related to CLAD, because it is observed in both, isograft and allograft recipients.     

核磁共振法表征硫黄用量对天然橡胶交联密度及结构的影响

用核磁共振(NMR)法测定了硫黄用量及硫化温度对天然橡胶(NR)硫化胶交联结构的影响,并与传统的平衡溶胀法进行了对比.结果表明,用NMR法可以测定硫化胶的总交联密度、未硫化胶的物理交联密度和由于交联反应产生的化学交联密度;NR硫化胶的总交联密度和化学交联密度随硫黄用量的增加而呈线性增加;随着硫黄用量的增加.交联密度增加,NR硫化胶的纵向弛豫时间和横向弛豫时间下降;NR硫化胶的交联密度越大,弛豫时间对温度的依赖性越小;NMR法可以清晰展示NR/硫黄/促进剂NS硫化体系的硫化过程中橡胶交联点间的相对分子质量、化学交联密度及橡胶大分子连到橡胶交联网络上的演变过程.     

Effects of functional electrical stimulation in denervated thigh muscles of paraplegic patients mapped with T 2 imaging

OBJECT: Functional electrical stimulation (FES) for paraplegic patients, with the long-term goal of ultimately restoring muscle function, is associated with several positive effects: improvement of blood circulation, skin condition, peripheral trophism and metabolism, prophylaxis against decubitus ulcer and better physical fitness. Since fibres of denervated muscles (lacking a supplying nerve) need to be activated directly, the fraction of elicited muscle tissue follows the geometric distribution of the electrical field, which can be simulated using electrophysiological computer models. Experimental validation of these results, however, has not yet been established. MATERIALS AND METHODS: We acquired T (2) parameter images using a multislice multi-spin-echo MR sequence before and immediately after FES in nine denervated paraplegic patients and three healthy subjects in order to visualise the geometric distribution of activation by electrically induced muscle stimulation in denervated versus innervated (healthy) thigh muscle. RESULTS AND CONCLUSION: After realigning and normalisation, maps of relative T (2) increase were calculated. The results demonstrate that the spatial distribution of short-term effects of FES of denervated muscle tissue of paraplegic patients who regularly perform FES can be visualised by T (2) parameter images. This may be used to refine models of the electrical field of FES in muscle and fibre activation in the future.     

Dietary Modulation of the Human Gut Microbiota and Metabolome with Flaxseed Preparations

Flaxseeds are typically consumed either as whole flaxseed, ground flaxseed, flaxseed oil, partially defatted flaxseed meal, or as a milk alternative. They are considered a rich source of vitamins, minerals, proteins and peptides, lipids, carbohydrates, lignans, and dietary fiber, which have shown hypolipidemic, antiatherogenic, anticholesterolemic, and anti-inflammatory property activity. Here, an in vitro batch culture model was used to investigate the influence of whole milled flaxseed and partially defatted milled flaxseed press cake on the gut microbiota and the liberation of flaxseed bioactives. Microbial communities were profiled using 16S rRNA gene-based high-throughput sequencing with targeted mass spectrometry measuring lignan, cyclolinopeptide, and bile acid content and HPLC for short-chain fatty acid profiles. Flaxseed supplementation decreased gut microbiota richness with Firmicutes, Proteobacteria, and Bacteroidetes becoming the predominant phyla. Secoisolariciresinol, enterodiol, and enterolactone were rapidly produced with acetic acid, butyric acid, and propionic acid being the predominant acids after 24 h of fermentation. The flaxseed press cake and whole flaxseed were equivalent in microbiota changes and functionality. However, press cake may be superior as a functional additive in a variety of foods in terms of consumer acceptance as it would be more resistant to oxidative changes.     

Fast electrochemical Detection of Nitro- and Aminoaromates in Soils and Liquids

The land sites of former explosives factories as well as troop exercise areas are frequently contaminated by 2,4,6-Trinitrotoluene (TNT). As decontamination approaches, a direct on-site measurement is necessary for a risk estimation. In contrast to ordinary analytics done in laboratories the employed methods are required to be fast and inexpensive. Additionally, they should be highly selective and sensitive. Up to now cyclic voltammetry is seldom used as an electrochemical method in the sensoric field. The presented new sensorsystem for the detection of TNT based on cyclic voltammetry fulfills the demands mentioned above.