Primary beer fermentation by immobilised yeast—a review on flavour formation and control strategies

Immobilised cells are increasingly being used in bio‐industries and may also have benefits for the brewing industry. The major challenge to applying this technology successfully in breweries is focused on the main fermentation in combination with the secondary fermentation. In particular, the control and fine‐tuning of the flavour profile during the main fermentation require further investigation. In this review, the influence of immobilised cell technology on the production of the flavour‐active compounds (i.e. higher alcohols, esters and vicinal diketones) is discussed. Control strategies that are based on the manipulation of parameters during fermentation such as temperature, feed volume, wort gravity, wort composition and aeration are explained. Finally, bioreactor configurations that may facilitate immobilised cells in performing the primary fermentation are evaluated. Copyright © 2006 Society of Chemical Industry     

Counterdiffusion protein crystallisation in microgravity and its observation with PromISS (protein microscope for the international space station)

The crystallisation by counterdiffusion is a very efficient technique for obtaining high-quality protein crystals. A prerequisite for the use of counterdiffusion techniques is that mass transport must be controlled by diffusion alone. Sedimentation and convection can be avoided by either working in gelled systems, working in systems of small dimensions, or in the absence of gravity. We present the results from experiments performed on the ISS using the Protein Microscope for the International Space Station (PromISS), using digital holography to visualise crystal growth processes. We extensively characterised three model proteins for these experiments (cablys3*lysozyme, triose phosphate isomerase, and parvalbumin) and used these to assess the ISS as an environment for crystallisation by counterdiffusion. The possibility to visualise growth and movement of crystals in different types of experiments (capillary counterdiffusion and batch-type) is important, as movement of crystals is clearly not negligible.     

Fluctuations in instantaneous clearness index: Analysis and statistics

Solar radiation is characterized by short fluctuations introduced by passing clouds. An analysis of these fluctuations with regard to solar energy applications should focus on the instantaneous clearness index. Its probability distribution for a given mean clearness index is, as a first approximation, independent from the season and partly also from the site. This is verified for four annual datasets from three different sites.An analysis of fluctuations in solar radiation must focus on their amplitude, persistence, and frequency of occurrence rather than their location in time. The Fourier analysis cannot satisfactorily provide this information since time series of the instantaneous clearness index exhibit no periodicity. Instead, a localized spectral analysis based on wavelet bases rather than on periodic-ones has been applied. This analysis allows the decomposition of the fluctuating clearness index signal into a set of orthonormal subsignals. Each of them represents one specific scale of persistence of the fluctuation.The annual mean square values of all subsignals have been analysed, permitting the allocation of the signal’s power content to the different scales of persistence of a fluctuation. These annual mean values agree well for the different datasets, indicating the existence of statistically significant mean square values of the fluctuations as a function of their persistence.The analysis offers a valuable tool for the estimation of power flow fluctuations introduced by direct solar energy systems. With further elaboration it may be applied by power system operators for network planning in distribution grids with a high density of embedded generation.     

Networks of knowledge: The distributed nature of medical innovation

Innovation in medicine is a complex process that unfolds unevenly in time and space. It is characterised by radical uncertainty and emerges from innovation systems that can hardly be comprehended within geographical, technological or institutional boundaries. These systems are instead highly distributed across countries, competences and organisations. This paper explores the nature, rate and direction of the growth and transformation of medical knowledge in two specific areas of research, interventional cardiology and glaucoma. We analyse two large datasets of bibliometric information extracted from ISI and adopt an empirical network approach to try to uncover the fine structure of the relevant micro-innovation systems and the mechanisms through which these evolve along trajectories of change shaped by the search for solutions to interdependent problems.     

Conical Intersections: Relaxation,Dephasing, and Dynamics in a Simple Model

Conical intersections occur on potential energy surfaces of many medium-sized and larger molecules. Their investigation, which has been ongoing for more than six decades, shows that vibronic coupling and relaxation behaviors at conical intersections can become quite complex and show large quantum effects. We present calculations of dynamical behavior in very simple (two-dimensional, degenerate, non-displaced) conical intersection models. The focus is placed on the effects of bath interactions on conical behavior—that is, the extent to which electronic dephasing, nuclear relaxation, and electronic relaxation affect the initially excited wave packet evolving on conical intersection surface. The calculations are carried through using a density matrix picture, with a Lindblad semi-group formalism to characterize relaxation. We observe large quantum effects that act particularly on true conical structures (anti-symmetric with respect to the mixing coordinate), as opposed to comparable-strength interactions without this symmetry. Significant changes in excited-state population decay, and even larger and more striking changes in the (observable) bleach recovery signal, are found.     

Cognitive, behavioral, and family factors in the differentiation of depressive and anxiety disorders during childhood.

Contribution of cognitive, behavioral, and family environment variables to the differentiation of depressive and anxiety disorders in children was explored. 59 children from Grades 4–7 (14 diagnosed with a depressive disorder, 16 diagnosed with depressive and anxiety disorders, 11 diagnosed with an anxiety disorder, and 18 nondisturbed controls) completed measures of the depressive cognitive triad, depressive cognitions, social skills, family environment, and maladaptive family messages. Results of a stepwise discriminant function analysis indicated that 2 discriminant functions composed of 7 variables from the cognitive, behavioral, and family environment domains accounted for 91% of the between-groups variance. Results suggest that depressive disorders can be distinguished from anxiety disorders on the basis of ratings of cognition, social skills, and family environment. Implications for existing research and a model of depression during childhood are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Homophobia and the politics of objectivism: Commentary on Rosenbaum's (1995) "Comment."

Rosenbaum (1995) argued that the 1992 and 1993 volumes of Psychoanalytic Psychology detracted from the image of psychologists as being within science because they included articles about homophobia in psychoanalytic theory and practice. Labeling those who view homosexuality as a pathology "homophobic" is political, according to Rosenbaum, because such labeling is objective and neutral. I deconstruct Rosenbaum's use of the notions of objectivism and neutrality, and conclude that they function as masks for politics, ideology, and values. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electricity produced from renewable energy sources—What target are we aiming for?

In 2001, the European Commission (hereafter “EC”) formulated an ambitious target of 21% of total community electricity consumption to be generated with renewable energy sources by 2010. Moreover, national indicative targets per Member State were specified. In practice, the latter are implemented in all Member States as national production targets, achievable exclusively through an increase of the domestic production of electricity produced from renewable energy sources (hereafter “RES-E”). However, in this article it will be shown that this is not in line with the EC's intent. Looking at the legislative process resulting in the Directive on the promotion of RES-E, it is demonstrated that instead the EC aimed for European trade in renewable electricity through national consumption targets.     

Implantation Studies on Silicon-Doped GaN

Silicon-doped GaN layers grown by low-pressure metalorganic vapor-phase epitaxy with Si concentrations ranging from 2 × 10¹⁷ Si/cm³ to 9.2 × 10¹⁸ Si/cm³ were investigated by means of the perturbed angular correlation (PAC) technique applied to implanted ¹¹¹In(Cd). An undoped GaN film is used as a reference. The Si atoms replace Ga atoms in the lattice, and silicon, being a group IV element, acts as a donor on the Ga site and contributes one extra electron to the conduction band. Hall-effect measurements confirmed that the free charge carrier density is essentially increased and of the order of the silicon concentration. PAC investigations of the annealing behavior after implantation of the ¹¹¹In probes show that best recovery is achieved after annealing at 1200 K and that high silicon concentrations make GaN films more stable at high temperatures. Further, it was found that the temperature dependence of the electric field gradient is reduced by increasing Si concentrations.