Zur Bedeutung der Kundenzufriedenheit für im Schienenpersonennahverkehr tätige Unternehmen

Für die SPNV-Unternehmen werden die bei ihren Kunden erzielten bzw. erzielbaren Fahrgelderlöse in Zukunft eine erheblich stärkere Bedeutung erhalten. Der demografische Wandel und die zunehmende Motorisierung werden darüber hinaus dazu führen, dass die Gruppe der Captives abnehmen wird. Damit wird der SPNV nach und nach erhebliche Anteile seiner größten und zugleich wichtigsten Kundengruppe auf lange Sicht verlieren. Zugleich wird die Zahl der wahlfreien Kunden weiter steigen; damit steigt die Gefahr für das SPNV-Unternehmen, dass sich diese Personen verstärkt gegen eine Nutzung des SPNV entscheiden, sofern dieser die an ihn gestellten Qualitätsansprüche nicht erfüllt. Um weiterhin am Markt bestehen und die geplanten Fahrgelderlöse generieren zu können, ist es daher für SPNV-Unternehmen von strategischer Bedeutung, die Qualitätsanforderungen der Fahrgäste zu kennen, diese dann selektiv zu erfüllen, um die sich hieraus ergebenden Erlöspotenziale abschöpfen zu können. Die Kundenzufriedenheit wird dabei immer mehr zum entschei-denden Faktor zur Generierung der geplanten Fahrgelderlöse. Gleichzeitig stehen die SPNV-Unternehmen der Herausforderung gegenüber, ihr Angebot wirtschaftlicher realisieren zu müssen. Im Grunde handelt es sich um ein Optimierungsproblem, bei dem in Abhängigkeit vom Verkehrsvertrag einerseits und den Einstellungen und dem Verhalten der Fahrgäste andererseits die wirtschaftlichste Investitionsstrategie gesucht wird. Um das Optimierungsproblem lösen zu können, müssen Abhängigkeiten zwischen Maßnahmen, ihren wirtschaftlichen Dimensionen für das investierende Unternehmen, den Reaktionen der Fahrgäste sowie die Rahmenbedingungen eines Verkehrsvertrags bekannt sein. Die vorliegende Arbeit befasst sich mit dieser Fragestellung

Peptide-equipped tobacco mosaic virus templates for selective and controllable biomineral deposition

The coating of regular-shaped, readily available nanorod biotemplates with inorganic compounds has attracted increasing interest during recent years. The goal is an effective, bioinspired fabrication of fiber-reinforced composites and robust, miniaturized technical devices. Major challenges in the synthesis of applicable mineralized nanorods lie in selectivity and adjustability of the inorganic material deposited on the biological, rod-shaped backbones, with respect to thickness and surface profile of the resulting coating, as well as the avoidance of aggregation into extended superstructures. Nanotubular tobacco mosaic virus (TMV) templates have proved particularly suitable towards this goal: Their multivalent protein coating can be modified by high-surface-density conjugation of peptides, inducing and governing silica deposition from precursor solutions in vitro. In this study, TMV has been equipped with mineralization-directing peptides designed to yield silica coatings in a reliable and predictable manner via precipitation from tetraethoxysilane (TEOS) precursors. Three peptide groups were compared regarding their influence on silica polymerization: (i) two peptide variants with alternating basic and acidic residues, i.e. lysine–aspartic acid (KD)$_{χ}$ motifs expected to act as charge-relay systems promoting TEOS hydrolysis and silica polymerization; (ii) a tetrahistidine-exposing polypeptide (CA$_{4}$H$_{4}$) known to induce silicification due to the positive charge of its clustered imidazole side chains; and (iii) two peptides with high ZnO binding affinity. Differential effects on the mineralization of the TMV surface were demonstrated, where a (KD)$_{χ}$ charge-relay peptide (designed in this study) led to the most reproducible and selective silica deposition. A homogenous coating of the biotemplate and tight control of shell thickness were achieved

Moment Dynamics of Zirconia Particle Formation for Optimizing Particle Size Distribution

We study the particle formation process of Zirconia ( ZrO 2 )-based material. With a model-based description of the particle formation process we aim for identifying the main growth mechanisms for different process parameters. After the introduction of a population balance based mathematical model, we derive the moment dynamics of the particle size distribution and compare the model to experimental data. From the fitted model we conclude that growth by molecular addition of Zr-tetramers or Zr-oligomers to growing particles as well as size-independent particle agglomeration takes place. For the purpose of depositing zirconia-based material (ZrbM) on a substrate, we determine the optimal process parameters such that the mineralization solution contains preferably a large number of nanoscaled particles leading to a fast and effective deposition on the substrate. Besides the deposition of homogeneous films, this also enables mineralization of nanostructured templates in a bioinspired mineralization process. The developed model is also transferable to other mineralization systems where particle growth occurs through addition of small molecular species or particle agglomeration. This offers the possibility for a fast determination of process parameters leading to an efficient film formation without carrying out extensive experimental investigations

Peptide Controlled Shaping of Biomineralized Tin(II) Oxide into Flower-Like Particles

The size and morphology of metal oxide particles have a large impact on the physicochemical properties of these materials, e.g., the aspect ratio of particles affects their catalytic activity. Bioinspired synthesis routes give the opportunity to control precisely the structure and aspect ratio of the metal oxide particles by bioorganic molecules, such as peptides. This study focusses on the identification of tin(II) oxide (tin monoxide, SnO) binding peptides, and their effect on the synthesis of crystalline SnO microstructures. The phage display technique was used to identify the 7-mer peptide SnBP01 (LPPWKLK), which shows a high binding affinity towards crystalline SnO. It was found that the derivatives of the SnBP01 peptide, varying in peptide length and thus in their interaction, significantly affect the aspect ratio and the size dimension of mineralized SnO particles, resulting in flower-like morphology. Furthermore, the important role of the N-terminal leucine residue in the peptide for the strong organic–inorganic interaction was revealed by FTIR investigations. This bioinspired approach shows a facile procedure for the detailed investigation of peptide-to-metal oxide interactions, as well as an easy method for the controlled synthesis of tin(II) oxide particles with different morphologies

Deletion and recombination events between the DNA-A and DNA-B components of Indian cassava-infecting geminiviruses generate defective molecules in Nicotiana benthamiana

Cloned DNA-B components, belonging to the bipartite begomoviruses Indian cassava mosaic virus (ICMV) and Sri Lankan cassava mosaic virus (SLCMV), family Geminiviridae, when co-inoculated along with previously cloned DNA-A components of the respective viruses onto the experimental host Nicotiana benthamiana, generated defective DNAs (def-DNA) ranging in size from 549 to 1555 nucleotides. All the cloned def-DNAs contained the common region (CR) as well as portions of either DNA-A or DNA-B and, in a few cases, both DNA-A and DNA-B, representing recombinant products, the junction points of which correspond to repeats of 2-11 bases found in the parental molecules. The DNA-B-derived def-DNAs were, in some cases, associated with a decrease in levels of DNA-B, with a concomitant change in the symptoms from downward leaf curling in the older leaves to upward leaf-rolling in newly emerging leaves, more typical of monopartite begomoviruses

Adsorption and Self-Assembly of M13 Phage into Directionally Organized Structures on C and SiO₂ Films

A versatile method for the directional assembly of M13 phage using amorphous carbon and SiO₂ thin films was demonstrated. A high affinity of the M13 phage macromolecules for incorporation into aligned structures on an amorphous carbon surface was observed at the concentration range, in which the viral nanofibers tend to disorder. In contrast, the viral particles showed less freedom to adopt an aligned orientation on SiO₂ films when deposited in close vicinity. Here an interpretation of the role of the carbon surface in significant enhancement of adsorption and generation of viral arrays with a high orientational order was proposed in terms of surface chemistry and competitive electrostatic interactions. This study suggests the use of amorphous carbon substrates as a template for directional organization of a closely-packed and two-dimensional M13 viral film, which can be a promising route to mineralize a variety of smooth and homogeneous inorganic nanostructure layers