Chemistry and physics of dopants embedded in helium droplets

Helium droplets represent a cold inert matrix, free of walls with outstanding properties to grow complexes and clusters at conditions that are perfect to simulate cold and dense regions of the interstellar medium. At sub-Kelvin temperatures, barrierless reactions triggered by radicals or ions have been observed and studied by optical spectroscopy and mass spectrometry. The present review summarizes developments of experimental techniques and methods and recent results they enabled.     

Laser machining of GaN-on-diamond wafers

The commercialization of gallium-nitride microwave circuits on diamond substrates requires chip-dicing technology and via formation process compatible with standard semiconductor processes. This paper discusses issues related to dicing and drilling of GaN-on-diamond wafers for RF power transistor applications (die size < 1 mm²) using laser micromachining.     

Heterogeneously Catalyzed Hydrogenation of Supercritical CO2 to Methanol

Interest in energy storage technologies is still increasing in times of excess of electricity generated by wind farms or solar plants. A key part of the energy storage technologies plays the efficient conversion of H₂ and CO₂ from renewable resources. Here, the process conditions for continuous catalytic hydrogenation of CO₂ to CH₃OH under supercritical conditions over lab‐synthesized Cu/ZnO/Al₂O₃ catalysts were investigated. A possible in situ phase separation of reaction products within the reactor due to the higher densities of the reaction mixture by the higher pressure could affect the kinetics and simplify downstream processing. The combination of thermodynamic studies and catalytic performance tests for CO₂ hydrogenation under supercritical conditions is discussed and a process concept is presented.     

BioCatNet: A Database System for the Integration of Enzyme Sequences and Biocatalytic Experiments

The development of novel enzymes for biocatalytic processes requires knowledge on substrate profile and selectivity; this can be derived from databases and from publications. Often, these sources lack time‐course data for the substrate or product, and an unambiguous link between experiment and enzyme sequence. The lack of integrated, original data hampers the comprehensive analysis of enzyme kinetics and the evaluation of sequence–function relationships. In order to accelerate enzyme engineering, BioCatNet integrates protein sequence, protein structure, and experimental data for a given enzyme family. BioCatNet explicitly assigns the enzyme sequence to the experimental data, which consists of information on reaction conditions and time‐course data. BioCatNet facilitates the consistent documentation of reaction conditions, the archiving of time‐course data, and the efficient exchange of experimental data among collaborators. Data integration is demonstrated for three case studies by using the TEED (Thiamine diphosphate‐dependent Enzymes Engineering Database).     

Avoiding singularities in recurrent neural control for induction motors

In this paper, a master–slave synchronization scheme based on parameter identification is proposed to overcome the controller singularity problem that appears when linearization‐like techniques are applied in indirect adaptive neural control, like Neural Block Control (NBC). Such a synchronization strategy requires an identifier‐like recurrent neural network and an adaptive law to update the neural weights. The proposed adaptive law prevents both, specific adaptive weights zero‐crossing and the ‘parameter drift’ phenomenon. NBC consists of two tasks; synchronizing an identifier‐like recurrent neural network (slave) with the plant (master) and controlling the system based on the slave model. The effectiveness of the synchronization law is tested using NBC for controlling the angular speed and magnetic flux magnitude of an induction motor. Usingit a priori knowledge about the real plant, a high‐order recurrent neural network is proposed as the slave system. Based on the slave neural model, a discontinuous control law is derived, which combines Block Control and Sliding Modes. NBC with the proposed synchronization strategy is tested via simulations, comparing results with a standard parameters adaptive law. Copyright © 2011 John Wiley & Sons, Ltd.     

The Role of Tenascin C in Cardiac Reverse Remodeling Following Banding–Debanding of the Ascending Aorta

Background: Tenascin-C (TN-C) plays a maladaptive role in left ventricular (LV) hypertrophy following pressure overload. However, the role of TN-C in LV regression following mechanical unloading is unknown. Methods: LV hypertrophy was induced by transverse aortic constriction for 10 weeks followed by debanding for 2 weeks in wild type (Wt) and TN-C knockout (TN-C KO) mice. Cardiac function was assessed by serial magnetic resonance imaging. The expression of fibrotic markers and drivers (angiotensin-converting enzyme-1, ACE-1) was determined in LV tissue as well as human cardiac fibroblasts (HCFs) after TN-C treatment. Results: Chronic pressure overload resulted in a significant decline in cardiac function associated with LV dilation as well as upregulation of TN-C, collagen 1 (Col 1), and ACE-1 in Wt as compared to TN-C KO mice. Reverse remodeling in Wt mice partially improved cardiac function and fibrotic marker expression; however, TN-C protein expression remained unchanged. In HCF, TN-C strongly induced the upregulation of ACE 1 and Col 1. Conclusions: Pressure overload, when lasting long enough to induce HF, has less potential for reverse remodeling in mice. This may be due to significant upregulation of TN-C expression, which stimulates ACE 1, Col 1, and alpha-smooth muscle actin (α-SMA) upregulation in fibroblasts. Consequently, addressing TN-C in LV hypertrophy might open a new window for future therapeutics.     

Inter-governmental institutions as promoters of energy policy diffusion in a federal setting

This article is about diffusion processes behind the innovation of sub-national energy policy measures in a federal system. Typically for the federal political system in Switzerland, the elements of the energy policy field are shaped by the principle of subsidiarity. The aim is that cantons promote innovative problem solutions and regionally adapted implementation. For this reason, policy differences between cantons are large and create a need for coordination. More concretely, I will analyze the impact of inter-cantonal institutions on different innovations in the field of energy policy. The research question is approached with an event history analysis on three different innovative measures in the Swiss cantons from 1990 to 2007. A more comprehensive picture of diffusion in one policy field is drawn with this approach. The main contribution of this paper is the finding that intergovernmental institutions promote diffusion in one policy field only for measures with certain characteristics. The internal determinants are therefore not a sufficient explanation.