Structure determination and sensory evaluation of novel bitter compounds formed from β-acids of hop (Humulus lupulus L.) upon wort boiling

In order to screen for the bitter compounds generated from hop-derived precursors during the wort boiling process, an ethanolic hop extract was fractionated; the fractions obtained were thermally treated under model wort boiling conditions and, then, sensorially evaluated for their bitterness. Besides the isomerisation of the α-acids into the intensely bitter iso-α-acids, the bitterness of the fraction containing the β-acids was also found to be enhanced after wort boiling. To gain first insights into the β-acid-derived bitter compounds, the β-acid colupulone was isolated, thermally treated under wort boiling conditions and, then, investigated for bitter tasting degradation products by means of a taste dilution analysis (TDA). Besides the cohulupone, five previously unreported bitter-tasting colupulone degradation products, all of which exhibited a lingering, β-acid-like bitter taste with low recognition thresholds between 37.9 and 90.3 μmol/l, were isolated and their structures determined as two tricyclocolupone epimers, two dehydrotricyclocolupone epimers, and nortricyclocolupone, respectively, by means of LC–TOF–MS and 1D/2D-NMR spectroscopy.     

Medizin als gesellschaftliche Praxis, sozialwissenschaftliche Empirie und ethische Reflexion: ein Vorschlag für eine soziologisch aufgeklärte Medizinethik

Definition of the problem The central focus of Empirical Ethics is the study of the social and cultural aspects inherent in medical practice. Arguments This approach distinguishes between the scientific-cognitive aspects and the cultural-normative aspects of medicine, which would conventionally be investigated separately by the social sciences. When however medicine is conceived of as social practice, the sharp distinction between scientific medicine, culturally normative aspects and ethical reflection becomes less distinct. Conclusion We suggest combining ethical reflection and empirical research in multiple stages. In this case, social scientific analyses would provide an initial framework for understanding medical practices and a foundation for further ethical investigations, which would then allow for a sociological critique.     

Reasons for and developments in international scientific collaboration: does an Asia–Pacific research area exist from a bibliometric point of view?

This paper describes the different forms of and tries to give reasons for international scientific collaboration in general. It focuses on eleven countries in the Asia–Pacific region by evaluating their national research output with the help of bibliometric indicators in particular. Over two million journal articles published by these countries between 1998 and 2007 in ISI-listed periodicals are analyzed. Discipline-specific publication and citation profiles reveal national strengths and weaknesses in the different research domains. The exponential increase in publication output by China over the last few years is astonishing, but in terms of visibility, i.e. citation rates, China cannot keep up with leading science nations, remaining below the world average. A discipline-specific analysis shows that Chinese authors took an active part in more than a quarter of all articles and reviews published in the field of materials science in 2007, while their contribution to medical research is very low. Co-publication networks among the eleven countries are generated to observe the development of cooperation bonds in the region. Applying Salton’s measure of international collaboration strength, an above-average strengthening of scientific collaboration in the Asia–Pacific region can be observed.     

A Shift Towards Landscape-Scale Approaches in Compensation - Suitable Mechanisms and Open Questions

ABSTRACT

Landscape-scale mitigation approaches reflect a shift from a project-by-project approach to more strategic planning by applying the mitigation hierarchy – avoidance, minimization, compensation – for impacts on natural resources on a larger scale. This paper discusses requirements for the implementation of landscape-scale mitigation approaches in general. It continues with a criteria-based analysis of compensation mechanism under the Endangered Species Act – conservation banks, in-lieu fees, and permittee-responsible mitigation – to determine which mechanism best meets these requirements. Findings show that, in theory, conservation banks are best-suited to implement landscape-scale compensation. However, evidence for claimed benefits of third-party mitigation and large-scale mitigation approaches is lacking. The article concludes by identifying a number of open questions in the field.     

Natural variability in lake pH on seasonal, interannual and decadal time scales: implications for assessment of human impact

Reference values define the natural state with respect to environmental stressors and are commonly used for assessments of ecological impacts and to set restoration targets. These reference values are often treated as constants, whereas in reality they can be highly variable. Here, we study the significance of this variability for assessments of human impact on the environment, by using almost two decades of observations from 95 acid-sensitive Swedish lakes. Our approach was to first estimate the preindustrial, steady-state reference level of acid neutralization capacity (ANC) for each lake with the hydrogeochemical model MAGIC. Then the variability in pH around this "baseline" was reconstructed from the contemporary, "natural" variability in the ANC, total organic carbon (TOC) and Al-concentrations, and partial CO2 pressure. The variability in reference pH was then examined for the period 1990-2004, on seasonal (single measurements), interannual (1-year median), and decadal (5-year median) scales. On the seasonal scale, the variability in reference pH ranged between 0.40 and 1.7. The range on the interannual time scale was up to 1.3 units and for the decadal scale up to 0.76 units. Since an anthropogenic pH decline of more than 0.4 units is deemed significant according to the Swedish Environmental Quality Criteria, this natural variability clearly needs to be accounted for when assessing acidification.     

Maritime traffic management: a need for central coordination?

Traffic management is not formally organised in the maritime domain. Ships are autonomous and find their own way. Traffic is organised through rules, regulations, and “good seamanship”; it is a distributed system. In areas of high traffic-density support is proved by vessel traffic service (VTS) to promote traffic safety and fluency. VTS does not take control. This organisational structure has proven itself in situations with sufficient resources. When resources become insufficient (e.g. not enough sailing space), the traffic needs an organising mechanism. In this article, the authors argue that the most promising way to do this is by organising centralised planning coordination, whilst leaving maritime traffic a distributed system with no additional central control.     

Saccharomyces cerevisiae Gle2/Rae1 is involved in septin organization,essential for cell cycle progression

Gle2/Rae1 is highly conserved from yeast to humans and has been described as an mRNA export factor. Additionally, it is implicated in the anaphase‐promoting complex‐mediated cell cycle regulation in higher eukaryotes. Here we identify an involvement for Saccharomyces cerevisiae Gle2 in septin organization, which is crucial for cell cycle progression and cell division. Gle2 genetically and physically interacts with components of the septin ring. Importantly, deletion of GLE2 leads to elongated buds, severe defects in septin‐assembly and their cellular mislocalization. Septin‐ring formation is triggered by the septin‐regulating GTPase Cdc42, which establishes and maintains cell polarity. Additionally, activity of the master cell cycle regulator Cdc28 (Cdk1) is needed, which is, besides other functions, also required for G₂/M‐transition, and in yeast particularly responsible for initiating the apical–isotropic switch. We show genetic and physical interactions of Gle2 with both Cdc42 and Cdc28. Most importantly, we find that gle2? severely mislocalizes Cdc42, leading to defects in septin‐complex formation and cell division. Thus, our findings suggest that Gle2 participates in the efficient organization of the septin assembly network, where it might act as a scaffold protein. © 2017 The Authors. Yeast published by John Wiley & Sons, Ltd.     

The autonomy-safety-paradox of service robotics in Europe and Japan: a comparative analysis

Service and personal care robots are starting to cross the threshold into the wilderness of everyday life, where they are supposed to interact with inexperienced lay users in a changing environment. In order to function as intended, robots must become independent entities that monitor themselves and improve their own behaviours based on learning outcomes in practice. This poses a great challenge to robotics, which we are calling the “autonomy-safety-paradox” (ASP). The integration of robot applications into society requires the reconciliation of two conflicting aspects: increasing machine autonomy and ensuring safety in end-use. As the level of robot autonomy grows, the risk of accidents will increase, and it will become more and more difficult to identify who is responsible for any damage incurred. However, emphasizing safety impairs the autonomous functioning of the robot. This problem implies the need for a broadened concept of product safety. Our comparative study shows that the institutional framing of the ASP as well as concrete solutions to this problem differs between Europe and Japan in two respects: (1) the understanding of robot agency and (2) the concept of “appropriate” user–robot interaction.