Regionalisierte Darstellung der Nitratbelastung im Grundwasser Niedersachsens

Grundwasser - Zur Nitratbelastung im Grundwasser besteht aufgrund der intensiven Agrarwirtschaft in Niedersachsen ein besonderer Informationsbedarf. Die Auswertung von Punktdaten soll...     

Metformin: a biguanide

Metformin is an effective agent in the oral treatment of non-insulin-dependent diabetes mellitus and does not cause hypoglycemia like the sulfonylureas. This drug is safe provided the cautions and contraindications are followed and the patient is monitored for hepatic and renal function. Metformin is used extensively outside the United States in the treatment of type II diabetes and recently was approved by the FDA for marketing under the brand name of Glucophage.     

Influence of the structure of polymer fiber composites on the analysis of the zeta potential

This article addresses the questions about the influence of surface area, roughness, and sample mounting on the zeta potential analysis. A series of knitted yarns and fabrics of cotton and modacryl and their blends represent a real‐life model system to study these effects. The combination of the natural cotton and the man‐made modacryl makes possible to study the effect of the different origin for surface and interfacial charge and the surface area‐weighted contributions to the average zeta potential of a chemically heterogeneous composite material. In our study, two measuring cells of the SurPASS electrokinetic analyzer were used, namely the Cylindrical Cell and the Adjustable Gap Cell. Comparison of the results obtained in two different measuring cells was related to the measured material. We used the Cylindrical Cell for both the zeta potential analysis of yarn and knitted fabrics and compared these results with data obtained for knitted fabrics using the Adjustable Gap Cell. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46227.     

Electrochemical characterization of radiation-grafted ion-exchange membranes based on different matrix polymers

Seven proton conducting membranes based on different commercial fluoropolymer films were prepared by radiation grafting with styrene followed by sulfonation. These membranes were studied as candidates for fuel cell electrolyte membranes and compared to Nafion^® 105 and 117 with respect to conductivity, oxygen and hydrogen permeability, kinetics of the oxygen reduction reaction (ORR) and performance in a fuel cell. The dependence of the conductivity of the membranes on the relative humidity (RH) and temperature was also determined. The conductivity was observed to depend on the membrane thickness and the water uptake. The dependence of the conductivity on the temperature and the RH was the same for all of the experimental membranes. Reactant gas permeabilities appeared to depend only slightly on the matrix material and no major differences in the Tafel slopes and exchange current densities of the ORR were observed. Membranes with high water uptakes appeared to be less durable in the fuel cell than membranes with low water uptakes. Thus to prepare a membrane that is durable under the fuel cell conditions, the water uptake must remain low even at the expense of the conductivity.     

PROBA-V mission for global vegetation monitoring: standard products and image quality

PROBA-V is a new global vegetation monitoring mission, to be launched in the second quarter of 2013. PROBA-V has been developed to show a consistent performance with SPOT-VEGETATION (SPOT-VGT) data, with similar spectral bands but with an improved spatial resolution of 1/3 km. The innovative mission concept has led to several key research topics related to image quality, which are discussed in this article. To support the existing VEGETATION user community, the data products for PROBA-V continue to provide daily top of canopy synthesis (S1-TOC) and 10 day synthesis products (S10-TOC). In addition, the new top of atmosphere daily synthesis (S1-TOA) products and a radiometrically/geometrically corrected (level 1C) product in raw resolution will also be provided for scientific users.     

Preventing undesirable effects of mutual trust and the development of skepticism in virtual groups by applying the knowledge and information awareness approach

Empirical studies have proven the effectiveness of the knowledge and information awareness approach of Engelmann and colleagues for improving collaboration and collaborative problem-solving performance of spatially distributed group members. This approach informs group members about both their collaborators’ knowledge structures and their collaborators’ information. In the current study, we investigated whether this implicit approach reduces undesirable effects of mutual trust and mutual skepticism. Trust is an important influencing factor with regard to behavior and performance of groups. High mutual trust can have a negative impact on group effectiveness because it reduces mutual control and, as a result, the detection of the others’ mistakes. In an empirical study, 20 triads collaborating with the knowledge and information awareness approach were compared with 20 triads collaborating without this approach. The members of a triad were spatially distributed and participated in a computer-supported collaboration. The results demonstrated that the availability of the knowledge and information awareness approach overrides the negative impact of too much mutual trust and counteracts the development of mutual skepticism. This study contributes to further clarifying the impact of trust on effectiveness and efficiency of virtual groups depending upon different situational contexts.     

Subject Positions and Power Relations in Creative Organizations: Taking a Discursive View on Organizational Creativity

In this paper we take a discursive view on organizational creativity and examine subject positions and power relations produced within a discourse on creativity in two different kinds of creative organizations, an opera house and a games company. In particular, we focus on the ways in which the discourse is practised in creative production processes. The two cases illustrate how the macro‐level discourse on creativity can be enacted in a more micro‐level construction of subjectivities. In the study we identified several subject positions that were shared by both organizations, and examined how they were embedded in the organizations' formal and informal hierarchies. By taking a discursive approach to creativity, we have also been able to explore some unwanted consequences of emphasizing creativity in organizations.     

A Polyclonal Aptamer Library for the Specific Binding of the Gut Bacterium Roseburia intestinalis in Mixtures with Other Gut Microbiome Bacteria and Human Stool Samples

Roseburia intestinalis has received attention as a potential probiotic bacterium. Recent studies have demonstrated that changes in its intestinal abundance can cause various diseases, such as obesity, enteritis and atherosclerosis. Probiotic administration or fecal transplantation alter the structure of the intestinal flora, offering possibilities for the prevention and treatment of these diseases. However, current monitoring methods, such as 16S rRNA sequencing, are complex and costly and require specialized personnel to perform the tests, making it difficult to continuously monitor patients during treatment. Hence, the rapid and cost-effective quantification of intestinal bacteria has become an urgent problem to be solved. Aptamers are of emerging interest because their stability, low immunogenicity and ease of modification are attractive properties for a variety of applications. We report a FluCell-SELEX polyclonal aptamer library specific for R. intestinalis isolated after seven evolution rounds, that can bind and label this organism for fluorescence microscopy and binding assays. Moreover, R. intestinalis can be distinguished from other major intestinal bacteria in complex defined mixtures and in human stool samples. We believe that this preliminary evidence opens new avenues towards aptamer-based electronic biosensors as new powerful and inexpensive diagnostic tools for the relative quantitative monitoring of R. intestinalis in gut microbiomes.