Terpyridine-manganese complexes: A new class of bleach catalysts for detergent applications

Oxidation catalysis is one approach used to improve the performance of hydrogen peroxide in laundry bleach applications. We introduce herein a new class of bleach catalysts based on the ligand 2,2′∶6′,2″ terpyridine. A set of manganese complexes of substituted terpyridines was investigated with respect to their physicochemical properties and bleach performance. Introduction of electron-donating hydroxy and amine substituents in the 4-position of the individual pyridine rings improves the bleach performance in model experiments with morin (2′,3,4′,5,7-pentahydroxyflavone) in solution as well as on tea-stained cotton fabrics. All the catalysts show excellent bleach performance at 40 and 25°C under European washing conditions. Performance is superior to that of the activator tetraacetyl ethylenediamine (TAED) but depends critically on the substitution pattern. Dye damage caused by the catalysts is similar to that of TAED, proving that catalytic bleach systems with high performance and low damage are indeed feasible. Model experiments revealed that the complexes are highly stable under aqueous alkaline conditions in the presence of hydrogen peroxide. The optimal pH for catalytic activity is about 10. For a catalyst to have a high bleach performance, it must possess a sufficiently low activity to catalyze disproportionation of hydrogen peroxide, which is a major side reaction of catalytic bleach with manganese complexes. All the catalysts showed a similar affinity for the cotton fabric, suggesting that differences in bleach activity of complexes are not caused by differences in the fabric affinity.     

Process monitoring and quality variable prediction utilizing PLS in industrial fed-batch cell culture

Partial least squares is a data-driven modeling technique that has been utilized for process monitoring in a variety of industrial processes. This paper develops a novel online partial least squares approach (evolving PLS) and compares it with an existing online PLS technique (global PLS). Both methods are applied to an industrial fed-batch mammalian cell culture process, where process variables are used to predict a key quality variable, product titer. Fault detection and diagnosis are performed using PLS models and statistical metrics. This new detection approach was able to recognize a variety of faults during online monitoring.     

The principal components of natural images revisited

This paper investigates the principal components (PCs) of natural gray and color images. A horizontal and vertical typology of PCs is found which leads to the identification of groups of basis functions for steerable bandpass filters. Using this system, the contribution of spatio-chromatic structure to the total variance can be quantified for selected spatial frequencies.     

Reductive Decyanation of Annulated Aminocyclopropane-endo-carbonitriles – a way to annulated cyclopropane-exo-amines

Annulated Aminocyclopropane-endo-carbonitriles 11a,b are reductively decyanated by sodium in liquid ammonia with complete retention of configuration. An additionally existing chlorine atom in the starting materials 12a,c – e , thereby, is simulataneously replaced by hydrogen. The preparative advantage of this method is demonstrated by the selective access to 6α-H-isomers 13b and 13e as members of the ensemble of bicyclo[3.1.0]hexanediyl-dimorpholine diastereomers. A strong buckled bicyclohexane unit is present in 3α,6αisomer 13e as indicated by ¹H NMR spectroscopy and X-ray structural analysis.     

Aziridines. 69. Reactions of N-Acylaziridines with Sodium Metal and Sodium Naphthalenide. Elimination of olefines

Reactions of N-acylaziridines 1a – g (N-benzoyl except 1d ) with sodium or naphthalenide N ^.− in THF provide a variety of products that usually arise via the aziridino ketyls 2 . Homolytic ring opening of 2 generates the amidatoalkyl radicals 3 . Only with a very short reaction time were small amounts of benzil or benzoylnaphthalenes obtained indicating a reversible trapping of 2 by dimerization or coupling with N^.−. Homolysis of 2 produced always the more stable 3 apart from reactions of monomethylaziridines 1c , d where the primary radical i-3c , d is kinetically favoured. The amides R¹CONHCHR⁴CHR²R³ ( 9 , isopropylamides i - 9c , d from 1c , d ) were usually the main products. 9 arise from 3 either by H atom abstraction from THF (probably in sodium metal runs) or by reduction of 3 to carbanions 5 that abstract a proton from THF ( N^.− runs). Addition of 5a (R²⁻⁴ = H) to 1a gives finally the ketone 8a . Self reaction of primary radical 3a is dimerization. Self reaction of tertiary or secondary radicals is disproportionation when an allylamide arises. This isomerizes to an enamide unless it is conjugated. R²R³CCHR⁴ and R¹CONH₂ arise (probably) always. The mechanism, possibly a cyclic process of anion 6 , is not clear.     

Biochemistry,cell biology and molecular biology of lipids of Saccharomyces cerevisiae

The yeast Saccharomyces cerevisiae is a powerful experimental system to study biochemical, cell biological and molecular biological aspects of lipid synthesis. Most but not all genes encoding enzymes involved in fatty acid, phospholipid, sterol or sphingolipid biosynthesis of this unicellular eukaryote have been cloned, and many gene products have been functionally characterized. Less information is available about genes and gene products governing the transport of lipids between organelles and within membranes, turnover and degradation of complex lipids, regulation of lipid biosynthesis, and linkage of lipid metabolism to other cellular processes. Here we summarize current knowledge about lipid biosynthetic pathways in S. cerevisiae and describe the characteristic features of the gene products involved. We focus on recent discoveries in these fields and address questions on the regulation of lipid synthesis, subcellular localization of lipid biosynthetic steps, cross-talk between organelles during lipid synthesis and subcellular distribution of lipids. Finally, we discuss distinct functions of certain key lipids and their possible roles in cellular processes. © 1998 John Wiley & Sons, Ltd.     

A production planning system to continuously integrate the characteristics of reconfigurable manufacturing systems

Operation in a dynamic environment requires companies to constantly adapt their manufacturing systems to stay competitive. One approach to manufacturing is the use of reconfigurable manufacturing systems (RMS). Current production planning approaches cannot model and realize the production-side adaptions available in RMS. In this article a novel planning system for modeling that continuously integrates the key characteristics of RMS in production planning and control (PPC) is presented. First, the challenges for production planning using RMS are defined. A feasible planning system is then presented, based on modeling and specification approaches, followed by a planning method to realize capacity scalability and functionality changes in planning processes. Finally, a prototypical application is outlined and the planning system is evaluated with the help of different production scenarios. The application results demonstrate the feasibility of the planning system as well as the potential improvement of typical key performance indicators in manufacturing.     

Pericyclic Domino reactions with 3,6-Bis(trifluoromethyl)-1,2,4,5-tetrazine: A convenient entry into azo cage compounds

3,6-Bis(trifluoromethyl)-1,2,4,5-tetrazine ( 1 ) characterized by a highly reactive, electron deficient diazdiene system reacted with several cyclic and acyclic bis-dienophiles to yield the cage compounds 11 , 19a, b , 31a, b and 41 in a pericyclic homo-domino reaction in good yields. The first step of the domino reactions is an inverse electron demand inter-molecular Diels–Alder addition followed by elimination of nitrogen to give 4,5-dihydropyridazines which then undergo a terminal ring closure to yield the cage compounds. The solvent employed and the reaction temperature is of crucial importance. Whereas in nitromethane and at elevated temperatures the main products are the cage compounds, at lower temperature and in dichloromethane as solvent the initially formed 4,5-dihydropyridazines are frequently converted to 1,4-dihydropyridazines by a 1,3-H-shift. Treatment of the tetrazine 1 with cyclooctatriene 23 did not lead to a cage compound in any case; instead via valence tautomeric species octa-1,3,5,7-tetraene 23a and bicyclo[4.2.0]octa-2,4-diene 23b the twofold pyridazine-substituted butadienes 24 and 26 together with the tricyclic cyclobuta[f]phthalazine 25 were formed.     

Robust optimization of an airplane component taking into account the uncertainty of the design parameters

A slat track, structural component of an aircraft wing that transfers the aerodynamical loads, excited by operational forces can result in excessive displacement levels if not properly designed. The design parameter values are not always precisely known but can contain a level of uncertainty to some extent due to, for example dimensional variation. During the different optimization approaches, the slat track geometry is optimized in order to limit the maximum vertical displacement, taking into account the variability of the design parameters. Application and comparison of different optimal, robust and generalized optimization approaches is presented and applied on the slat track finite element model, making use of mean and variance response functions to model the uncertainty on the finite element displacement values. Next to validating different objective function statements, a comparison is also made on the level of accuracy and practicability concerning the different response function models, based on regression techniques and Monte Carlo simulations, optimization and transmissibilities and regressive techniques and vibration reduction over a frequency range. Copyright © 2008 John Wiley & Sons, Ltd.     

Hierarchical schemes for curve representation

The performance of three curve representation schemes are compared. They are the strip-tree, Bezier-curve-employing, and arc-tree methods. Each scheme represents a curved shape as a hierarchy of approximations, where higher levels in the hierarchy correspond to coarser approximations of the curve. In addition, each approximation typically corresponds to a bounding area that encloses the actual curve. When geometric operations are computed, coarse approximation of the curve are initially addressed and finer approximation levels are processed if necessary. It is shown that the three representations differ in the choice of bounding areas, the type and amount of information stored at each approximation level, and the method of deciding whether to proceed to finer approximations