2,163 research outputs found
Assessing the Disruptiveness of New Energy Technologies - An Ex-Ante Perspective
For those organizations that experience disruption, they usually understand the situation when it is already too late. The real challenge to any theory, especially if it is of high relevance for managers, is how it performs predictively. Can the theory of disruptive technologies be used not only to analyze cases ex post but to predict the potential disruptive technologies ex ante? Established companies are skeptical of the idea of disruptiveness, because of the difficulty of making predictions given the ex post nature of the theory. In this regard the goal of this report is to provide a general measure of disruptiveness and develop a framework that can assess technologies whether they have the potential to be proven disruptive. The developed assessment framework captures the essential characteristic and holistic success factors for disruptive technologies based on the theory of Christensen and a number of clarifications as seen in the literature. The framework is applied and validated by assessing the disruptive potential of five renewable energy technologies (wind energy, solar energy, biomass, hydro power, geothermal) in the power generation, heating and transportation sectors of four European countries (Austria, Bulgaria, Germany and Romania). The results show the applicability of the framework and give insights into technology and country specific determinants of energy market sector disruptions. (authors' abstract)Series: Working Papers / Institute for Strategic Management / Energy & Strategy Think Tan
Highly oriented poly(di-n-alkylsilylene) films on oriented PTFE substrates
Highly oriented polysilylene layers have potential applications in electrophotography, nonlinear optics, display fabrication, and microlithography. The preparation of such layers by crystallization on a highly oriented PTFE substrate is reported, and their assessment by optical birefringence, electron diffraction and dichroic infrared experiments described. Why this orientation technique works is not yet clear, especially as it can be applied to poly(di-n-alkylsilylen)s with different crystal structures. Several possible underlying mechanisms are discussed
IL-36Îł has proinflammatory effects on human endothelial cells
Interleukin-36 cytokines are predominantly expressed by epithelial cells. Significant upregulation of epidermal IL-36 is now a recognised characteristic of psoriatic skin inflammation. IL-36 is known to induce inflammatory responses in dendritic cells, fibroblasts and epithelial cells. Although vascular alterations are a hallmark of psoriatic lesions and dermal endothelial cells are well known to play a critical role in skin inflammation, the effects of IL-36 on endothelial cells are unexplored. We here show that endothelial cells including dermal microvascular cells express a functionally active IL-36 receptor. Adhesion molecules VCAM-1 and ICAM-1 are upregulated by IL-36Îł stimulation and this is reversed by the presence of the endogenous IL-36 receptor antagonist. IL-36Îł stimulated endothelial cells secrete the proinflammatory chemokines IL-8, CCL2 and CCL20. Chemotaxis assays showed increased migration of T cells following IL-36Îł stimulation of endothelial cells. These results suggest a role for IL-36Îł in the dermal vascular compartment and it is likely to enhance psoriatic skin inflammation by activating endothelial cells and promoting leukocyte recruitment. This article is protected by copyright. All rights reserved
The Neural Substrates of Subjective Time Dilation
An object moving towards an observer is subjectively perceived as longer in duration than the same object that is static or moving away. This âtime dilation effectâ has been shown for a number of stimuli that differ from standard events along different feature dimensions (e.g. color, size, and dynamics). We performed an event-related functional magnetic resonance imaging (fMRI) study, while subjects viewed a stream of five visual events, all of which were static and of identical duration except the fourth one, which was a deviant target consisting of either a looming or a receding disc. The duration of the target was systematically varied and participants judged whether the target was shorter or longer than all other events. A time dilation effect was observed only for looming targets. Relative to the static standards, the looming as well as the receding targets induced increased activation of the anterior insula and anterior cingulate cortices (the âcore control networkâ). The decisive contrast between looming and receding targets representing the time dilation effect showed strong asymmetric activation and, specifically, activation of cortical midline structures (the âdefault networkâ). These results provide the first evidence that the illusion of temporal dilation is due to activation of areas that are important for cognitive control and subjective awareness. The involvement of midline structures in the temporal dilation illusion is interpreted as evidence that time perception is related to self-referential processing
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Beyond Janus Geometry: Characterization of Flow Fields around Nonspherical Photocatalytic Microswimmers
Catalytic microswimmers that move by a phoretic mechanism in response to a self-induced chemical gradient are often obtained by the design of spherical janus microparticles, which suffer from multi-step fabrication and low yields. Approaches that circumvent laborious multi-step fabrication include the exploitation of the possibility of nonuniform catalytic activity along the surface of irregular particle shapes, local excitation or intrinsic asymmetry. Unfortunately, the effects on the generation of motion remain poorly understood. In this work, single crystalline BiVO4 microswimmers are presented that rely on a strict inherent asymmetry of charge-carrier distribution under illumination. The origin of the asymmetrical flow pattern is elucidated because of the high spatial resolution of measured flow fields around pinned BiVO4 colloids. As a result the flow from oxidative to reductive particle sides is confirmed. Distribution of oxidation and reduction reactions suggests a dominant self-electrophoretic motion mechanism with a source quadrupole as the origin of the induced flows. It is shown that the symmetry of the flow fields is broken by self-shadowing of the particles and synthetic surface defects that impact the photocatalytic activity of the microswimmers. The results demonstrate the complexity of symmetry breaking in nonspherical microswimmers and emphasize the role of self-shadowing for photocatalytic microswimmers. The findings are leading the way toward understanding of propulsion mechanisms of phoretic colloids of various shapes
Active BiVO 4 swimmers propelled by depletion gradients caused by photodeposition
Artificial active matter often selfâpropels by creating gradients of one or more species or quantities. For chemical swimmers, most frequently either O2 or H+ that are created in certain catalytic reactions are causing the interfacial flows which drive the selfâpropulsion. While the palette of reactions is extending constantly, especially toward more bioâcompatible fuels, the depletion of species is often overlooked. Here, the photodeposition of metal species on BiVO4 micro swimmers is considered. During the photodeposition reaction, metal ions are removed from the solution creating a depleted region around the particle. The ability of this depletion to drive active motion of artificial micro swimmers, as well as the influences of different metal ions and counter ions on the motion are investigated and cross compared
Simultaneous preconcentration of 9Be and cosmogenic 10Be for determination of the 10Be/9Be ratio in (coastal) seawater
Beryllium isotopes have emerged as a quantitative tracer of continental weathering, but accurate and precise determination of the cosmogenic 10Be and stable 9Be in seawater is challenging, because seawater contains high concentrations of matrix elements but extremely low concentrations of 9Be and 10Be. In this study, we develop a new, time-efficient procedure for the simultaneous preconcentration of 9Be and 10Be from (coastal) seawater based on the iron co-precipitation method. The concentrations of 9Be, 10Be, and the resulting 10Be/9Be ratio for Changjiang Estuary water derived from the new procedure agree well with those obtained from the conventional procedure requiring separate preconcentration for 9Be and 10Be determinations. By avoiding the separate preconcentration, our newly developed procedure contributes toward more time-efficient handling of samples, less sample cross-contamination, and a more reliable 10Be/9Be ratio. Prior to this, we validated the iron co-precipitation method using artificial seawater and natural water samples from the Amazon Estuary regarding: (1) the âmatrix effectâ for Be analysis, (2) its extraction efficiency for pgâgâ1 levels Be in the presence and absence of organic matter, and (3) the data comparability with another preconcentration method. We calculated that for the determination of 9Be and 10Be in most open ocean seawater with typical 10Be concentrations of >â500 atomsâgâ1, good precisions (<â5%) can be achieved using less than 3âliters of seawater compared to more than 20âliters routinely used previously. Even for coastal seawater with extremely low 10Be concentration (e.g., 100 atomsâgâ1), we estimate a maximum amount of 10âliters to be adequate
Contextual Flexibility in Pseudomonas aeruginosa Central Carbon Metabolism during Growth in Single Carbon Sources.
Pseudomonas aeruginosa is an opportunistic human pathogen, particularly noted for causing infections in the lungs of people with cystic fibrosis (CF). Previous studies have shown that the gene expression profile of P. aeruginosa appears to converge toward a common metabolic program as the organism adapts to the CF airway environment. However, we still have only a limited understanding of how these transcriptional changes impact metabolic flux at the systems level. To address this, we analyzed the transcriptome, proteome, and fluxome of P. aeruginosa grown on glycerol or acetate. These carbon sources were chosen because they are the primary breakdown products of an airway surfactant, phosphatidylcholine, which is known to be a major carbon source for P. aeruginosa in CF airways. We show that the fluxes of carbon throughout central metabolism are radically different among carbon sources. For example, the newly recognized "EDEMP cycle" (which incorporates elements of the Entner-Doudoroff [ED] pathway, the Embden-Meyerhof-Parnas [EMP] pathway, and the pentose phosphate [PP] pathway) plays an important role in supplying NADPH during growth on glycerol. In contrast, the EDEMP cycle is attenuated during growth on acetate, and instead, NADPH is primarily supplied by the reaction catalyzed by isocitrate dehydrogenase(s). Perhaps more importantly, our proteomic and transcriptomic analyses revealed a global remodeling of gene expression during growth on the different carbon sources, with unanticipated impacts on aerobic denitrification, electron transport chain architecture, and the redox economy of the cell. Collectively, these data highlight the remarkable metabolic plasticity of P. aeruginosa; that plasticity allows the organism to seamlessly segue between different carbon sources, maximizing the energetic yield from each.IMPORTANCE Pseudomonas aeruginosa is an opportunistic human pathogen that is well known for causing infections in the airways of people with cystic fibrosis. Although it is clear that P. aeruginosa is metabolically well adapted to life in the CF lung, little is currently known about how the organism metabolizes the nutrients available in the airways. In this work, we used a combination of gene expression and isotope tracer ("fluxomic") analyses to find out exactly where the input carbon goes during growth on two CF-relevant carbon sources, acetate and glycerol (derived from the breakdown of lung surfactant). We found that carbon is routed ("fluxed") through very different pathways during growth on these substrates and that this is accompanied by an unexpected remodeling of the cell's electron transfer pathways. Having access to this "blueprint" is important because the metabolism of P. aeruginosa is increasingly being recognized as a target for the development of much-needed antimicrobial agents
A common approach for absolute quantification of short chain CoA thioesters in prokaryotic and eukaryotic microbes
Background
Thioesters of coenzyme A participate in 5% of all enzymatic reactions. In microbial cell factories, they function as building blocks for products of recognized commercial value, including natural products such as polyketides, polyunsaturated fatty acids, biofuels, and biopolymers. A core spectrum of approximately 5â10 short chain thioesters is present in many microbes, as inferred from their genomic repertoire. The relevance of these metabolites explains the high interest to trace and quantify them in microbial cells.
Results
Here, we describe a common workflow for extraction and absolute quantification of short chain CoA thioesters in different gram-positive and gram-negative bacteria and eukaryotic yeast, i.e. Corynebacterium glutamicum, Streptomyces albus, Pseudomonas putida, and Yarrowia lipolytica. The approach assessed intracellular CoA thioesters down to the picomolar level and exhibited high precision and reproducibility for all microbes, as shown by principal component analysis. Furthermore, it provided interesting insights into microbial CoA metabolism. A succinyl-CoA synthase defective mutant of C. glutamicum exhibited an unaffected level of succinyl-CoA that indicated a complete compensation by the L-lysine pathway to bypass the disrupted TCA cycle. Methylmalonyl-CoA, an important building block of high-value polyketides, was identified as dominant CoA thioester in the actinomycete S. albus. The microbe revealed a more than 10,000-fold difference in the abundance of intracellular CoA thioesters. A recombinant strain of S. albus, which produced different derivatives of the antituberculosis polyketide pamamycin, revealed a significant depletion of CoA thioesters of the ethylmalonyl CoA pathway, influencing product level and spectrum.
Conclusions
The high relevance of short chain CoA thioesters to synthetize industrial products and the interesting insights gained from the examples shown in this work, suggest analyzing these metabolites in microbial cell factories more routinely than done so far. Due to its broad application range, the developed approach appears useful to be applied this purpose. Hereby, the possibility to use one single protocol promises to facilitate automatized efforts, which rely on standardized workflows
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