Grundwasseranbindung von alten Tagebaurestseen im Niederlausitzer Braunkohlentagebaugebiet

Groundwater with high acidity often leads to strongly acidic residual lakes in the vicinity of abandoned open pit lignite mines. Residual lake 77 (RL77) in Lower Lusatia (Germany) belongs to a sequence of residual lakes accomplishing groundwater drainage. A two-part high resolution three-dimensional groundwater model was set-up for the estimation of groundwater discharge into RL77. The objective of the simulations was to quantify the hydraulic component of the mass balance of the lake. The calculated total discharge could be distinguished with respect to water entering from the dump areas (11.3 l s ^?1 ) and from the undisturbed sediments (3.1 l s ^?1 ). The discharge was further distinguished with respect to the vertical entrance location into the temporarily stratified lake. It showed that groundwater discharged into the epilimnion of the lake at a rate of 9.7 l s ^?1 and into the hypolimnion at a rate of 4.7 l s ^?1 . Both the large fraction of water from the dump areas and the preferential entrance into the oxygen rich epilimnion of the lake have an adverse effect on lake water quality.     

Sterilization effects on starPEG coated polymer surfaces: characterization and cell viability

Sterilization is frequently an issue for polymeric biomaterials including hydrogels, where autoclaving needs to be discarded, and γ-irradiation and low temperature hydrogen peroxide gas plasma sterilization are already important alternatives. Coatings based on poly(ethylene glycol) are a well-known strategy to reduce unspecific protein interactions on biomaterial surfaces. Dense, ultrathin coatings of isocyanate terminated star-shaped poly(ethylene glycol) (starPEG) molecules have proven to be resistant to unspecific adsorption of proteins and enable direct biofunctionalization. The effectivity and stability of the starPEG coatings on poly(vinylidene fluoride) (PVDF) were studied after γ-irradiation (normed dosis 25 kGy) and plasma sterilization (Sterrad 100S). The selected surface properties determined were: surface composition (X-ray photoelectron spectroscopy, XPS), wettability (sessile drop contact angle) and protein adsorption by fluorescence microscopy (Avidin-TexasRed, Bovine Serum Albumin-Rhodamin). Preliminary cell experiments with the cell line L929 were performed prior and after sterilization to investigate the cell repellence of the starPEG coatings as well as cell viability and specific cell adhesion on GRGDS-modified coatings. The starPEG coating undergoes a slight oxidation due to plasma and γ-sterilization; this represents a minor variation confirmed by XPS and contact angle results. The non-sterilized starPEG and the plasma-sterilized coatings are protein repellent, however the protein adsorption on starPEG coated substrates is much stronger after γ-sterilization for both avidin and bovine serum albumin. The cell experiments indicate that the starPEG coatings are appliable homogeneously by incubation and are non-cell adherent. Moreover, after both sterilization processes the starPEG coatings remain cell repellent and the GRGDS-modified coatings presented vital cells. Thus we conclude that the plasma sterilization is more convenient for the starPEG coatings and GRGDS-modified starPEG coatings.     

Biofunctionalized poly(ethylene glycol)-<Emphasis Type="Italic">block</Emphasis>-poly(ε-caprolactone) nanofibers for tissue engineering

Electrospun fibers with contrasting cell adhesion properties provided non-woven substrates with enhanced in vitro acceptance and controllable cell interactions. Poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) block copolymers with varying segment lengths were synthesized in two steps and characterized by NMR and GPC. A cell adhesive peptide sequence, GRGDS, was covalently coupled to the PEG segment of the copolymer in an additional step. The suitability of polymers with molecular weights ranging from 10 to 30 kDa for electrospinning and the influences of molecular weight, solvent, and concentration on the resulting morphologies were investigated. Generally, electrospun fibers were obtained by electrospinning polymers with molecular weight larger than 25 kDa and concentrations of 10 wt%. Methanol/chloroform (25/75, v/v) mixtures proved to be good solvent systems for electrospinning the PEG-b-PCL and resulted in hydrophilic, non-woven fiber meshes (contact angle 30°). The mesh without cell adhesive GRGDS ligands showed no attachment of human dermal fibroblasts after 24 h cell culture demonstrating that the particular combination of the material and electrospinnig conditions yielded protein and cell repellent properties. The GRGDS immobilized mesh showed excellent cellular attachment with fibroblasts viable after 24 h with spread morphology. Electrospun nanofibers based on block copolymers have been produced which are capable of specifically targeting cell receptor binding and are a promising material for tissue engineering and controlling cell material interactions.     

Adjunct starter properties affect characteristic features of Swiss-type cheeses

A large number of microorganisms, both starter microorganisms and non-starter lactic acid bacteria originating from the base milk, or from various contamination sources during cheese manufacture, is associated with cheese ripening and the formation of flavour, texture and aroma. Under controlled conditions, Emmental and Bergk?se, a Gruyère-type cheese variety, were produced from pasteurised milk with standard starters and defined strains of facultatively heterofermentative lactobacilli (FHL), and partly with addition of a defined mixture of enterococci. Lactobacillus casei subsp. casei and L. rhamnosus (two strains each) were selected with respect to their potential for the utilisation of citric acid and ribose as sole energy source. The FHL developed up to 10(8) cfu/g within the first weeks of ripening, and viable counts in mature cheeses were 10(7) cfu/g, independent of the cheese variety. Bergk?se made with addition of L. rhamnosus strains showed a more pronounced proteolysis, resulting in reduced firmness and elasticity values of the cheese body, and FHL strains able to utilise citric acid improved the appearance of the cheeses by increasing the number of small eyes to the desired level. In Emmental cheese, the citric acid (+) strains reduced the intensity of propionic acid formation as the FHL apparently competed with the propionibacteria, and enterococci disappeared completely during maturation. Although further work is needed the study shows that, depending on the cheese variety, particular properties of FHL adjunct starters significantly affect important quality attributes of the resulting cheeses.     

Coffees rich in chlorogenic acid or N-methylpyridinium induce chemopreventive phase II-enzymes via the Nrf2/ARE pathway in vitro and in vivo

Recently, the coffee constituents 5-O-caffeoylquinic acid (CGA) and N-methylpyridinium (NMP) were identified as inducers of the Nrf2/antioxidant-response element (ARE) detoxifying pathway under cell-culture condition. To study the impact of CGA and NMP on the Nrf2-activating properties of a complex coffee beverage, two different model coffees were generated by variation of the roasting conditions: a low-roast coffee rich in CGA and a heavy-roast low in CGA but containing high levels of NMP. Activation of the Nrf2/antioxidant-response element pathway was monitored in vitro and in vivo.     

Colour of hard cheese

During ripening, body colour of Emmental cheeses was evaluated by tristimulus reflectance measurements. Tristimulus primaries were transformed to the Helmholtz system and into CIELAB-coordinates in order to obtain interpretable results. Apart from lightness decreasing with increasing maturation time, it was found by using both systems that, (1) colourfulness increased continuously up to a cheese age of approximately 10 weeks and then remained constant, and (2) the hue of the cheese body shifted towards a slightly more orange colour in the last stage of ripening. The yellowness index, which represents a one-dimensional measure calculated from tristimulus primaries, is proposed as a simple and adequate measure of cheese body colour, and interrelations with CIELAB-values commonly used in food science are outlined.     

Nanomagnetic logic: compact modeling of field-coupled computing devices for system investigations

In this paper we investigate error rates of nanomagnetic logic devices with perpendicular magnetization by compact modeling. Two different types of nanomagnets for information propagation and logic computing are introduced. The switching behavior of field-coupled nanomagnets is measured and analyzed. A compact model is derived from physics and experimental results are applied to the magnetic compact model. General requirements for fabrication parameters and clocking fields for reliable operation are extracted. We perform simulations and measurements on single devices to demonstrate the accuracy of the macromodel. Simulations on complex systems show that the error rate of a field-coupled magnetic system strongly depends on the variation of the switching field and the strength of the coupling field between the nanomagnets. The error rate of a 1-bit full adder is investigated for varying dot parameters. The results demonstrate the importance of fast simulation tools for investigations on the design of nanomagnetic computing devices and systems.     

The effect of technology information on consumer expectations and liking of beef

European consumers increasingly attach value to process characteristics of food. Although beef technologies are hardly communicated to consumers, providing consumer-oriented information about technology application might increase perceived transparency and consumer acceptance. This study investigates how information about beef technologies influences consumer expectations and liking of beef. Beef consumers in Belgium (n = 108) and Norway (n = 110) participated in an information experiment combined with sensory testing in which each consumer tasted three beef muscles treated with different technologies: unprocessed tenderloin M. Psoas major, muscle profiled M. Infraspinatus, and marinated (by injection) M. Semitendinosus. The findings indicate that detailed information about beef technologies can enhance consumers' expectations and liking of beef. However, this effect differs between countries and beef technologies. Information becomes either less relevant when the product is actually tasted, as indicated by the findings in Norway, or more relevant when information is confirmed by own experience during tasting, as indicated by the findings in Belgium.     

Batch Verification of Short Signatures

With computer networks spreading into a variety of new environments, the need to authenticate and secure communication grows. Many of these new environments have particular requirements on the applicable cryptographic primitives. For instance, a frequent requirement is that the communication overhead inflicted be small and that many messages be processable at the same time. In this paper, we consider the suitability of public key signatures in the latter scenario. That is, we consider (1)?signatures that are short and (2)?cases where many signatures from (possibly) different signers on (possibly) different messages can be verified quickly. Prior work focused almost exclusively on batching signatures from the same signer. We propose the first batch verifier for messages from many (certified) signers without random oracles and with a verification time where the dominant operation is independent of the number of signatures to verify. We further propose a new signature scheme with very short signatures, for which batch verification for many signers is also highly efficient. Combining our new signatures with the best known techniques for batching certificates from the same authority, we get a fast batch verifier for certificates and messages combined. Although our new signature scheme has some restrictions, it is very efficient and still practical for some communication applications.