Ein Planungsansatz zum Umgang mit Störungen bei der Produktion: Die flexible Produktionsfeinplanung mithilfe von Planungsschritten

Disruptions like the breakdown of machines or delays in the delivery of materials cause generated production plans to be useless, at least in some parts. A new planning approach for coping with this uncertainty caused by disruptions is presented. Planning steps that are described by properties, preconditions and consequences are used for material requirements planning and scheduling. If their preconditions are satisfied in a certain state of environment, planning steps will be applicable. The consequences of planning steps change the state of environment. Each customer order establishes a goal of a new planning problem to be achieved by applying planning steps. Plan execution concerns all planning steps applicable in a certain state of environment. In choosing among applicable planning steps and among available resources the flexibility of plan execution is preserved.     

Changes of physicochemical indicators during mastitis and the effects of milk ejection on their sensitivity

We examined the relationship between physicochemical indicators and somatic cells in the milk of dairy cows during experimentally induced mastitis and their significance as indicators for use in controlling udder health. We were concerned particularly with the effect of alveolar milk ejection on the sensitivity of these indicators. In Expt 1, Escherichia coli lipopolysaccharide (Esch. coli LPS) was injected into the left rear quarter to induce an inflammatory reaction in one quarter in each of six cows. The contralateral control quarter was injected with a solution of NaCl (9 g/l). Nine milk samples were taken from both quarters until 60 h after injection. In Expt 2, repeated milk samples were taken every 20 s from one quarter during a 120-s teat stimulation in 20 cows with different somatic cell counts (SCC). Quarters were clustered for low (<5.0 log cells/ml), mid (5.0-5.7 log cells/ml) and high (>5.7 log cells/ml) SCC of the sample taken at t=0 s. Samples were analysed for SCC, electrical conductivity (EC) and Na+ and Cl- concentrations. During the experimental inflammation SCC, EC, Na+ and Cl- peaked at 12 h from LPS administration and values in treated quarters (T) at this time were elevated to 7900, 157, 501 and 169% of the values in untreated quarters, respectively. In Expt 2, SCC, EC, Na+ and Cl- in high SCC quarters were 2520, 121, 283 and 141% of low SCC quarters at the start of stimulation (t=0 s), respectively. Highly significant (P<0.001) differences in EC, Na+ and Cl- between high and low SCC quarters disappeared owing to the onset of alveolar milk ejection 100 s after the first contact with the teat. In conclusion, SCC in cows' milk provided the strongest amplitude in the case of an intramammary inflammation. EC, Na+ or Cl- were useful tools only if the measurements were performed in cisternal milk before the start of alveolar milk ejection.     

Effective electrode configuration for selective stimulation with inner eye prostheses

The quality of visual perception with retinal prostheses strongly depends on the local selectivity. Electrode arrays at the surface of the retina should excite exclusively cells within a local area but they are expected to co-stimulate bypassing axons originating from ganglion cells of the outer regions. Long electrodes parallel to these axons are shown to be good candidates for avoiding the co-stimulation phenomenon. Efficiency of focal excitation depends on the length and resistance of the electrodes.     

New modules for PCR-based gene targeting in Candida albicans: rapid and efficient gene targeting using 100 bp of flanking homology region

The use of PCR-based techniques for directed gene alterations has become a standard tool in Saccharomyces cerevisiae. In our efforts to increase the speed of functional analysis of Candida albicans genes, we constructed a modular system of plasmid vectors and successfully applied PCR-amplified functional analysis (FA)-cassettes in the transformation of C. albicans. These cassettes facilitate: (a) gene disruptions; (b) tagging of 3'-ends of genes with green fluorescent protein (GFP); and (c) replacements of endogenous promoters to achieve regulated expression. The modules consists of a core of three selectable marker genes, CaURA3, CaHIS1 and CaARG4. Modules for C-terminal GFP-tagging were generated by adding GFP-sequences flanked at the 5'-end by a (Gly-Ala)3-linker and at the 3'-end by the S. cerevisiae URA3-terminator to these selection markers. Promoter exchange modules consist of the respective marker genes followed by the regulatable CaMAL2 or CaMET3 promoters at their 3'-ends. In order to ensure a reliably high rate of homologous gene targeting, the flanking homology regions required a size of 100 bp of gene-specific sequences, which were provided with the oligonucleotide primers. The use of shorter flanking homology regions produced unsatisfactory results with C. albicans strain BWP17. With these new modules only a minimal set of primers is required to achieve the functional analysis of C. albicans genes and, therefore, provides a basic tool to increase the number of functionally characterized C. albicans genes of this human pathogen in the near future.     

(R)-acetoin-female sex pheromone of the summer chafer Amphimallon solstitiale (L.)

Extracts of Amphimallon solstitiale (L.), a well known, widely distributed and rather common European scarab beetle, were analyzed by GC-MS and GC-EAD. Acetoin -(R):(S) < 9:1 - as well as 2,3-butanediol -(2R,3R):(2S,3S) :meso = 1:1:9 - were present in extracts of both males and females. Although (2S,3S)-butanediol did not show any EAD activity, the other compounds elicited strong responses exclusively with male antennae. In contrast, several EAD active green leaf volatiles were detected equally well by male and female antennae. During preliminary field bioassays, (R)-acetoin was highly attractive to swarming males, whereas neither rac-acetoin nor the 2,3-butanediols showed activity. Therefore, (R)-acetoin is the female sex pheromone of A. solstitiale.     

Attomole peptide analysis by high-pressure matrix-assisted laser desorption/ionization Fourier transform mass spectrometry

A new high-pressure matrix-assisted laser desorption/ionization (HP-MALDI) source for FTMS has recently been described (O'Connor et al. J. Am. Soc. Mass Spectrom., in press). Improvements to the source design, including the incorporation of a new high-pressure gas channel plate, resulted in ions devoid of metastable fragmentation and also in increased sensitivity compared to the HP-MALDI prototype source design. The focus of this contribution is the evaluation of the current HP-MALDI FTMS configuration. The use of nonconductive sample surfaces, such as Parafilm and Teflon, was explored, and spectra from 30 amol of peptide applied to these surfaces were routinely obtained. In addition, the current limit of detection for this configuration is demonstrated to be 300 zmol for the phosphopeptide RRREEE(pS)EEEAA using multishot accumulation of the ions from 15 laser shots in the hexapole and 1 scan. In addition, the performance of the new HP-MALDI FTMS configuration and its potential application for high-throughput proteomics analyses are discussed.     

Surface Structure of Oxygen Annealed Donor Doped SrTiO3(100) Single Crystals Studied with Spectroscopic Electron Microscopy

Heating 5at.% (on A-site) La-doped SrTiO₃(100) single crystals in an ambient atmosphere at 1300°C for 120 h results in the formation of insulating islands on top of the surface with typical dimensions of up to 50 m. The islands and the surface between them were investigated by spectroscopic Metastable Impact Electron Emission Microscopy (specMIEEM) and Photoelectron Emission Microscopy in order to determine its electronic and geometric structure.The comparison of specMIEEM results with MIES (Metastable Impact Electron Spectroscopy) spectra from stoichiometric SrO shows that the insulating islands, which most likely consist of SrO, are at least partly covered by another species, probably SrO₂. All these islands are surrounded by 2–3 m wide haloes. The electronic structure of these haloes is quite different from that of SrO and SrTiO₃ but similar to the electronic structure of TiO₂ or Ti₂O₃. It is suggested that the depletion of SrO from Ruddlesden-Popper (Sr _{n + 1}Ti _n O_{3n + 1}) phases results in the formation of SrO islands.     

Induction of apoptosis in human microvascular endothelial cells by divalent cobalt ions. Evidence for integrin-mediated signaling via the cytoskeleton

Wound healing following implantation is characterized by an acute inflammatory reaction and a subsequent reorganizing phase in which angiogenesis is involved. Endothelial cells (EC) participate in both inflammation and angiogenesis. Thus, the effects on functions of EC exerted by implanted materials could affect the progression of wound healing. The corrosion of metallic implants can cause high concentrations of heavy metal ions in the peri-implant tissues. The purpose of the present study was to test the effects of possible corrosion products on the function and viability of human EC in vitro. Long-term exposure of EC to CoCl2 and NiCl2 (3 days, 0.7 mM) leads to a decrease of cell number and changes in cellular morphology. However, the morphological changes between CoCl2- and NiCl2-treated cells differ significantly. The changed morphology of CoCl2-treated EC and the fragmented DNA pattern indicates apoptosis. Nickel-treated cells demonstrated necrosis. The activity of integrins was tested by an assay of cellular adhesion on collagen-coated surfaces. It was shown that the number of adherent cells significantly decreased upon exposure to CoCl2. Our studies suggest that induction of cell death in EC upon exposure to CoCl2 could be attributed to impaired integrin signaling, which leads to a damaged cytoskeleton and culminates in apoptosis.     

Polyionic fusion peptides function as specific dimerization motifs

The de novo design of a molecular adapter for directed associationand covalent linkage of two polypeptides is presented. Usingpeptides containing charged amino acid residues and an additionalcysteine residue (AlaCysLys₈ and AlaCysGlu₈) we demonstratethat the electrostatic interaction promotes the associationof two synthetic peptides and, subsequently, disulfide bondformation. The reaction depends on both the redox potentialand on the ionic strength of the buffer. Varying the redox potential,the interaction of the peptides was quantified by a G^0' of 6.6± 0.2 kcal/mol. Heterodimerization of the peptides ishighly specific, a competition of association by other cysteinecontaining compounds could not be observed. Two proteins comprisingcysteine-containing polyionic fusion peptides, a modified Fabfragment and an -glucosidase fusion, could be specifically conjugatedby directed association and subsequent disulfide bond formation.Both proteins retain their functional characteristics withinthe bifunctional conjugate: enzymatic activity of the glucosidaseand antigen-binding capacity of the Fab fragment are equivalentto the non-conjugated components.