Lipid class separation by HPLC combined with GC FA analysis: Comparison of seed lipid compositions from different <Emphasis Type="Italic">Brassica napus</Emphasis> L. varieties

A reliable HPLC method was established to evaluate the lipid composition of useful plants modified by breeding techniques. This study focused on the polar lipid distribution and polar lipid FA compositions of four rapeseed varieties. Structure and quantity of the distinct lipid classes were compared by HPLC using ELSD followed by a GC FA analysis. A baseline separation of 14 lipid classes could be achieved within one step by using an eluent gradient of hexane, tert-methylbutyl ether, isopropanol, acetonitrile, chloroform, triethylamine, acetic acid, and water supplemented with ammonium sulfate with a polyvinyl alcohol column. After automatic fractionation, the FA compositions of the distinct lipid classes were characterized by a subsequent complementary GC FA analysis through direct acetylchloride methylation. The rape varieties analyzed showed diversity in polar lipid content and distribution, dominated by PC, PE, PI, monoglycosyldiacylglycerols, and phytosterols. Extensive variations were detected in FA within the lipid classes of rape varieties with predominantly oleic acid, linoleic acid, and α-linolenic acid observed followed by palmitic acid and gondoic acid. Oleic acid was mainly connected to PC and linoleic acid to PE, whereas α-linolenic acid and γ-linolenic acid were predominantly linked to PI in all varieties.     

Structure–reactivity relationships in VOx/TiO2 catalysts for the oxyhydrative scission of 1-butene and n-butane to acetic acid as examined by in situ-spectroscopic methods and catalytic tests

Different VO_x/TiO₂ catalyst have been catalytically tested and studied by in situ-spectroscopic methods (FT-IR, UV/vis, EPR) in the oxyhydrative scission (OHS) of 1-butene and n-butane to acetic acid (AcOH). While 1-butene OHS follows the sequence butene → butoxide → ketone → AcOH/acetate with a multitude of side products also formed, n-butane OHS leads to AcOH, CO_x and H₂O only. Water vapour in the feed improves AcOH selectivity by blocking adsorption sites for acetate. The admixture of Sb₂O₃ was found to improve AcOH selectivity which is due to deeper V reduction under steady state conditions and lowering of surface acidity. VO_x/TiO₂ catalysts with sulfate-containing anatase are the most effective ones. Covalently bonded sulfate at the catalyst surface causes specific bonding of VO_x, stabilizes active V species and ensures their high dispersity.     

Synthesis and stochastic assessment of cost-optimal schedules

We treat the problem of generating cost-optimal schedules for orders with individual due dates and cost functions based on earliness/tardiness. Orders can run in parallel in a resource-constrained manufacturing environment, where resources are subject to stochastic breakdowns. The goal is to generate schedules while minimizing the expected costs. First, we estimate the distribution of each order type by simulation (assuming a reasonable machine/load model) and derive from the cost-function an optimal offset from the due date of each individual order. Second, these optimal offsets are then used to guide the generation of schedules which are responsible to resolve resource conflicts. Third, we evaluate the generated schedules by simulation. The approach is demonstrated by means of a non-trivial case-study from lacquer production. Optimal offsets are derived with the Modest/Möbius tool, schedules are generated using Uppaal Cora. The experimental results show that our approach achieves good results in all considered scenarios, and better results than an approach based on adding slack to processing times.     

From Centralized Workflow Specification to Distributed Workflow Execution

Current workflow management systems fall short of supporting large-scale distributed, enterprise-wide applications. We present a scalable, rigorously founded approach to enterprise-wide workflow management, based on the distributed execution of state and activity charts. By exploiting the formal semantics of state and activity charts, we develop an algorithm for transforming a centralized state and activity chart into a provably equivalent partitioned one, suitable for distributed execution. A synchronization scheme is developed that guarantees an execution equivalent to a non-distributed one. This basic solution is further refined in order to reduce communication overhead and exploit parallelism between partitions whenever possible. The developed synchronization schemes are compared in terms of the number and size of synchronization messages.     

Oxidation of alcohols using RuMnCe catalysts

The combination of ruthenium, manganese as well as cerium oxides formed an active catalytic system for the oxidation of 2-octanol and other alcohols. The addition of manganese species as promotors resulted in more active catalysts than comparable cobalt-doped oxidic materials. The application of RuMnCe oxides on redox-active supports, such as TiO₂ or CeO₂, by deposition–precipitation caused a further improvement of catalytic activity. A tolerance to nitrogen-containing substrates was observed.     

Innovative Stahltragwerke für das Museo del Acero in Mexiko

The former industrial site ‘Parque Fundidora’ in Monterrey, Mexico was turned into a museum site with entertainment facilities. Within these modifications a disused steel mill was converted to a steel museum, showing past and present of the local steelwork industry. The museum opened to the public in the fall of 2007 and was immediately designated a “Monumento Nacional de Mexicox”. One part of the museum complex is the old steel mill that was refurbished and made accessible by open‐air walkways. Another part of the Museo del Acero is a new building that is connected to the existing structure at ground floor level. Due to the site's topography, the new building is partially located underground. Three elements are particularly noteworthy when considering the new building: the facetted roof of the Steel Gallery, a wide‐spanning helical stair, and an extremely transparent glass façade with a lightweight supporting structure made out of steel. These three structures are described in the following article.     

Cellulose as an extracellular matrix component present in Enterobacter sakazakii biofilms

Cellulose was identified and characterized as an extracellular matrix component present in the biofilm of an Enterobacter sakazakii clinical isolate grown in nutrient-deficient (M9) medium. Using a bacterial artificial cloning approach in Escherichia coli and subsequent screening of transformants for fluorescence on calcofluor plates, nine genes organized in two operons were identified as putatively responsible for the biosynthesis of cellulose. In addition to the genes already described for cellulose production, two more genes were identified, putatively transcribed together with the genes from the first operon. Putative cellulose in E. sakazakii ES5 biofilm grown on glass coverslips was visualized by calcofluor staining and confocal fluorescence laser scanning microscopy. For the first time, the presence of cellulose in biofilms produced by E. sakazakii was confirmed by methylation analysis.     

Model of a solar driven steam jet ejector chiller and investigation of its dynamic operational behaviour

The solar driven steam jet ejector chiller (SJEC) is a new device for solar air-conditioning. Previously, solar SJEC has been only investigated theoretically by static models and practically by small test rigs. A demonstration plant does not exist so far, so that the operational behaviour of a solar SJEC has not been investigated in detail yet. But due to the fact that solar irradiation and cold demand are not constant, the operational behaviour is very important for the plant design and the controlling concept. This publication presents a model for a SJEC and the results of dynamic simulations. The proposed model allows creating and investigating different plant concepts by its structure in model components. After the validation of the model, simulations of a fictive solar SJEC with parabolic trough collectors are accomplished to analyse the dynamic operational behaviour of a future plant.     

Cell motility probed by noise analysis of thickness shear mode resonators

The quartz crystal microbalance (QCM) technique is an emerging bioanalytical tool to study the behavior of animal cells in vitro. Due to the high interfacial sensitivity of thickness shear mode (TSM) resonators it is possible to monitor the formation and breakage of cell-matrix interactions and changes in viscoelasticity of the cell bodies, as well as minute cell volume alterations by the time course of their resonance frequency even with millisecond time resolution. We found that mammalian MDCK-II cells grown on TSM resonators impose characteristic fluctuations on the resonance frequency, which are a quantitative indicator for dynamic activities of the cells on the surface and report on their vitality and motility. Applying noise analysis to the fluctuating resonance frequency allows one to quantify the response of the cells to environmental changes such as osmotic stress, addition of fixation reagents, or the influence of drugs such as cytochalasin D. The corresponding power density spectra of the noise imposed on the resonance frequency by the dynamic activities of the cells show a characteristic resonance at 1-2 Hz, which can be substantially altered by osmotic stress, fixation agents, or cytochalasin D. Comparison of QCM-based fluctuation readings with electric cell--substrate impedance sensing (ECIS)--a well-established technique to monitor cell dynamics-provides substantially different results, indicating that both techniques may complement each other with respect to their biological information. Whereas ECIS readings report solely on cell shape changes, QCM-based fluctuation analysis is also influenced by fluctuations in the viscoelasticity of the cell bodies.