Steganographie und Wasserzeichen – Aktueller Stand und neue Herausforderungen

Zusammenfassung Digitale Mediendaten (z. B. Bild-, Ton-, Videodaten oder aber auch symbolische Repr?sentationen) haben in den letzten Jahren stark an Bedeutung gewonnen. Sie ?ffnen neue M?rkte und Anwendungsfelder, erfordern aber gleichzeitig auch neue Sicherheitsmechanismen zum Schutz der Mediendaten, zur Identifikation oder Authentisierung in verschiedenen Repr?sentationsformen bis hin zum Schutz urheberrechtlicher Ansprüche.     

纤维素纤维及其混纺机织物的连续前处理

描述了德国Zschimmer＆Schwarz公司开发的机织物前处理系统Optasize和Optasteam。，结果表明：用Optasize／Optasteam工艺可应用在日常生产中，并为定制加工提供解决方案以满足客户要求，其流程简洁经济而且可靠性高。通过采用这一工艺最初不同起因的织物质量差异可由此拉平。     

A structure for efficient update,incremental redisplay and undo in graphical editors

The design of a graphical editor requires a solution to a number of problems, including how to (1) support incremental redisplay, (2) control the granularity of display updates, (3) provide efficient access and modification to the underlying data structure, (4) handle multiple views of the same data and (5) support Undo operations. It is most important that these problems be solved without sacrificing program modularity. A new data structure, called an ItemList, provides a solution to these problems. ItemLists maintain both multiple views and multiple versions of data to simplify Undo operations and to support incremental display updates. The implementation of ItemLists is described and the use of ItemLists to create graphical editors is presented.     

"Soft" metallic contact to isolated C60 molecules

C60 adsorbed on a monolayer of hexaazatriphenylene-hexanitrile (HATCN) on Ag(111) is investigated by ultraviolet photoelectron spectroscopy (UPS) and scanning tunneling microscopy. UPS and quantum-mechanical modeling show that HATCN chemisorbed on Ag(111) displays metallic character. This metallic molecular layer decouples C60 electronically from the Ag substrate and simultaneously acts both as template for the stable adsorption of isolated C60 molecules at room temperature and as "soft" metallic contact for subsequently deposited molecules.     

Reprocessing of aluminum chips by hot backward extrusion

In this work the recycling of cold pressed aluminum chips by a hot backward extrusion process is investigated. By using a non-melting approach common casting losses are avoided. After cold compaction, the hot backward extrusion process is carried out with a high speed hydraulic forming press under variation of forming speed, temperature and force. Subsequently, forged parts were analysed by mechanical tests and metallographic examinations. The investigations have shown that aluminum chips can be consolidated into a semi-finished part with local relative densities up to 100 %. In comparison to common continuous non-melting chip recycling techniques the investigated process chain has the potential to reduce the effort of post-treatment noticeable by producing semi-finished components from aluminum waste.     

DNA-oligonucleotide encapsulating liposomes as a secondary signal amplification means

A novel liposome-based signal amplification system was developed by encapsulating DNA oligonucleotides within antibody-tagged liposomes and subsequently detecting the oligonucleotide with dye-encapsulating liposomes for double signal enhancement. In this sandwich immunoassay, the model analyte, protective antigen protein from B. anthracis, was captured by one set of antibodies immobilized in microtiter plate wells and detected using a second antibody conjugated to oligonucleotide-encapsulating liposomes. Bound liposomes were lysed releasing the encapsulated fluorescein-tagged DNA 25-mer probe, which was then permitted to hybridize with its complementary sequence immobilized in a second plate. Finally, the amount of oligonucleotide was detected through the addition of anti-fluorescein antibody tagged dye-encapsulating liposomes. These secondary liposomes allowed for a approximately 400x lower LOD than detection of the fluorescein-labeled probe alone. Several aspects were investigated, including the encapsulation of various oligonucleotide concentrations within liposomes; oligonucleotide hybridization times and buffers; degree of anti-fluorescein antibody coverage on the liposomes; and immobilized anti-protective antigen antibody concentration. We found that the encapsulation efficiency increased with the starting oligonucleotide concentration. As many as 4000 DNA 25-mers were successfully entrapped in the liposome, and minimal leakage was observed over the course of 8 months. When used in the sandwich immunoassay, a limit of detection of 4.1 ng/mL protective antigen was observed with an upper limit of 5000 ng/mL. Due to the endless combination of DNA oligonucleotide sequences, this assay lends itself perfectly for multiplexing on the order of tens to hundreds of analytes.     

Application of ganglioside-sensitized liposomes in a flow injection immunoanalytical system for the determination of cholera toxin

Cholera, an acute infectious disease associated with water and seafood contamination, is caused by the bacterium Vibrio cholerae, which lives and colonizes in the small intestine and secretes cholera toxin (CT), a causative agent for diarrhea in humans. Based on earlier lateral flow assays, a flow injection liposome immunoanalysis (FILIA) system with excellent sensitivity was developed in this study for the determination of CT at zeptomole levels. Ganglioside (GM1), found to have specific affinity toward CT, was inserted into the phospholipid bilayer during the liposome synthesis. These GM1-sensitized, sulforhodamine B (SRB) dye-entrapping liposomes were used as probes in the FILIA system. Anti-CT antibodies were immobilized in its microcapillary. CT was detected by the formation of a sandwich complex between the immobilized antibody and GM1 liposomes. During the assay, the sample was introduced first into the column, and then liposomes were injected to bind to all CT captured by the antibody in the microcapillary. Subsequently, the SRB dye molecules were released from the bound liposomes via the addition of the detergent octyl glucopyranoside. The released dye molecules were transported to a flow-through fluorescence detector for quantification. The FILIA system was optimized with respect to flow rate, antibody concentration, liposome concentration, and injected sample volume. The calibration curve for CT had a linear range of 10-16 to 10-14 g mL-1. The detection limit of this immunosensor was 6.6 x 10(-17) g mL-1 in 200-microL samples (equivalent to 13 ag or 1.1 zmol).