2,027 research outputs found
Jets and High-Et Phenomena
The working group on jets and high-Et phenomena of the Future physics at HERA
Workshop studied subjects ranging from next-to-leading order (NLO) corrections
in deeply inelastic scattering (DIS) and photoproduction with the corresponding
determinations of physical quantities, to the physics of instanton-induced
processes, where a novel non-perturbative manifestation of QCD could be
observed. Other centres of interest were the physics of the forward direction,
the tuning of event generators and the development of a new generator which
includes a consistent treatment of the small- and large- QCD evolution. The
recommendations of the working group concerning detector upgrades and machine
luminosity are summarized
A SITUATION AWARENESS DRIVEN DESIGN FOR PREDICTIVE MAINTENANCE SYSTEMS: THE CASE OF OIL AND GAS PIPELINE OPERATIONS
The acquisition and processing of events from sensors or enterprise applications in real-time represent an essential part of many application domains such as the Internet of Things (IoT), offering benefits to predict the future condition of equipment to prevent the occurrence of failures. Many organisations already use some form of predictive maintenance to monitor performance or keep track of emerging business situations. However, the optimal design of applications to allow an effective Predictive Mainte-nance System (PMS) capable of analysing and processing large amounts of data is only scarcely exam-ined by Information Systems (IS) research. Due to the number, frequency, and the need for near-real-time evaluation systems must be capable of detecting complex event patterns based on spatial, temporal, or causal relationships on data streams (i.e. via Complex Event Processing). At the same time, however, due to the technical complexity, available systems today are static, since the creation and adaptation of recognisable situations results in slow development cycles. In addition, technical feasibility is only one prerequisite for predictive maintenance. Users must be capable of processing this vast amount of data presented without considerable cognitive effort. Precisely this challenge is even more daunting as op-erational maintenance personnel have to manage business-critical decisions with increasing frequency and short time. Research in Human Factors (HF) suggests Situation Awareness (SA) as a crucial sys-tem’s design paradigm allowing human beings to understand and anticipate the information available effectively. Building on this concept, this paper proposes a PMS for promoting operational decision makers’ Situation Awareness by three design principles (DP): Sensing, Acting, and Tracking. Based on these DPs, we implemented a PMS prototype for a scenario in Oil and Gas pipeline operations. Our finding suggest that the use of SA is of particular interest in realizing effective PMS
Response of pseudomonas putida KT2440 to phenol at the level of membrane proteome
This study led to the extension and refinement of our current model for the global response of Pseudomonas putida KT2440 to phenol by getting insights into the adaptive response mechanisms involving the membrane proteome. A two-dimensional gel electrophoresis based protocol was optimized to allow the quantitative comparison of membrane proteins, by combining inner and outer membrane fractionation with membrane protein solubilization using the detergent dodecylmaltoside. Following phenol exposure, a coordinate increased content of protein subunits of known or putative solvent efflux pump systems (e.g. TtgA, TtgC, Ttg2A, Ttg2C, and PP_1516-7) and a decreased content of porins OprB, OprF, OprG and OprQ was registered, consistent with an adaptive response to reduce phenol intracellular concentration. This adaptive response may in part be mediated by post-translational modifications, as suggested by the relative content of the multiple forms identified for a few porins and efflux pump subunits. Results also suggest the important role of protein chaperones, of cell envelope and cell surface and of a more active respiratory chain in the response to phenol. All these mechanistic insights may be extended to Pseudomonas adaptation to solvents, of possible impact in biodegradation, bioremediation and biocatalysis.PhD scholarship SFRH/BD/38805/200
Acute effects of ferumoxytol on regulation of renal hemodynamics and oxygenation
The superparamagnetic iron oxide nanoparticle ferumoxytol is increasingly used
as intravascular contrast agent in magnetic resonance imaging (MRI). This
study details the impact of ferumoxytol on regulation of renal hemodynamics
and oxygenation. In 10 anesthetized rats, a single intravenous injection of
isotonic saline (used as volume control) was followed by three consecutive
injections of ferumoxytol to achieve cumulative doses of 6, 10, and 41 mg
Fe/kg body mass. Arterial blood pressure, renal blood flow, renal cortical and
medullary perfusion and oxygen tension were continuously measured. Regulation
of renal hemodynamics and oxygenation was characterized by dedicated
interventions: brief periods of suprarenal aortic occlusion, hypoxia, and
hyperoxia. None of the three doses of ferumoxytol resulted in significant
changes in any of the measured parameters as compared to saline. Ferumoxytol
did not significantly alter regulation of renal hemodynamics and oxygenation
as studied by aortic occlusion and hypoxia. The only significant effect of
ferumoxytol at the highest dose was a blunting of the hyperoxia-induced
increase in arterial pressure. Taken together, ferumoxytol has only marginal
effects on the regulation of renal hemodynamics and oxygenation. This makes
ferumoxytol a prime candidate as contrast agent for renal MRI including the
assessment of renal blood volume fraction
The role of lysine palmitoylation/myristoylation in the function of the TEAD transcription factors
The TEAD transcription factors are the most downstream elements of the Hippo pathway. Their transcriptional activity is modulated by different regulator proteins and by the palmitoylation/myristoylation of a specific cysteine residue. In this report, we show that a conserved lysine present in these transcription factors can also be acylated, probably following the intramolecular transfer of the acyl moiety from the cysteine. Using Scalloped (Sd), the Drosophila homolog of human TEAD, as a model, we designed a mutant protein (Glu352Gln Sd ) that is predominantly acylated on the lysine (Lys350 Sd ). This protein binds in vitro to the three Sd regulators-Yki, Vg and Tgi-with a similar affinity as the wild type Sd, but it has a significantly higher thermal stability than Sd acylated on the cysteine. This mutant was also introduced in the endogenous locus of the sd gene in Drosophila using CRISPR/Cas9. Homozygous mutants reach adulthood, do not present obvious morphological defects and the mutant protein has both the same level of expression and localization as wild type Sd. This reveals that this mutant protein is both functional and able to control cell growth in a similar fashion as wild type Sd. Therefore, enhancing the lysine acylation of Sd has no detrimental effect on the Hippo pathway. However, we did observe a slight but significant increase of wing size in flies homozygous for the mutant protein suggesting that a higher acylation of the lysine affects the activity of the Hippo pathway. Altogether, our findings indicate that TEAD/Sd can be acylated either on a cysteine or on a lysine, and suggest that these two different forms may have similar properties in cells
ZnS Ultrathin interfacial layers for optimizing carrier management in Sb2S3-based photovoltaics
Antimony chalcogenides represent a family of materials of low toxicity and relative abundance, with a high potential for future sustainable solar energy conversion technology. However, solar cells based on antimony chalcogenides present open-circuit voltage losses that limit their efficiencies. These losses are attributed to several recombination mechanisms, with interfacial recombination being considered as one of the dominant processes. In this work, we exploit atomic layer deposition (ALD) to grow a series of ultrathin ZnS interfacial layers at the TiO2/Sb2S3 interface to mitigate interfacial recombination and to increase the carrier lifetime. ALD allows for very accurate control over the ZnS interlayer thickness on the ångström scale (0-1.5 nm) and to deposit highly pure Sb2S3. Our systematic study of the photovoltaic and optoelectronic properties of these devices by impedance spectroscopy and transient absorption concludes that the optimum ZnS interlayer thickness of 1.0 nm achieves the best balance between the beneficial effect of an increased recombination resistance at the interface and the deleterious barrier behavior of the wide-bandgap semiconductor ZnS. This optimization allows us to reach an overall power conversion efficiency of 5.09% in planar configuration
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Long-Living Holes in Grey Anatase TiO2 Enable Noble-Metal-Free and Sacrificial-Agent-Free Water Splitting
Titanium dioxide has been the benchmark semiconductor in photocatalysis for more than 40 years. Full water splitting, that is, decomposing water into H2 and O2 in stoichiometric amounts and with an acceptable activity, still remains a challenge, even when TiO2-based photocatalysts are used in combination with noble-metal co-catalysts. The bottleneck of anatase-type TiO2 remains the water oxidation, that is, the hole transfer reaction from pristine anatase to the aqueous environment. In this work, we report that “grey” (defect engineered) anatase can provide a drastically enhanced lifetime of photogenerated holes, which, in turn, enables an efficient oxidation reaction of water to peroxide via a two-electron pathway. As a result, a Ni@grey anatase TiO2 catalyst can be constructed with an impressive performance in terms of photocatalytic splitting of neutral water into H2 and a stoichiometric amount of H2O2 without the need of any noble metals or sacrificial agents. The finding of long hole lifetimes in grey anatase opens up a wide spectrum of further photocatalytic applications of this material. © 2020 The Authors. Published by Wiley-VCH Gmb
Purification and characterization of hydroquinone dioxygenase from Sphingomonas sp. strain TTNP3
Hydroquinone-1,2-dioxygenase, an enzyme involved in the degradation of alkylphenols in Sphingomonas sp. strain TTNP3 was purified to apparent homogeneity. The extradiol dioxygenase catalyzed the ring fission of hydroquinone to 4-hydroxymuconic semialdehyde and the degradation of chlorinated and several alkylated hydroquinones. The activity of 1 mg of the purified enzyme with unsubstituted hydroquinone was 6.1 μmol per minute, the apparent Km 2.2 μM. ICP-MS analysis revealed an iron content of 1.4 moles per mole enzyme. The enzyme lost activity upon exposure to oxygen, but could be reactivated by Fe(II) in presence of ascorbate. SDS-PAGE analysis of the purified enzyme yielded two bands of an apparent size of 38 kDa and 19 kDa, respectively. Data from MALDI-TOF analyses of peptides of the respective bands matched with the deduced amino acid sequences of two neighboring open reading frames found in genomic DNA of Sphingomonas sp strain TTNP3. The deduced amino acid sequences showed 62% and 47% identity to the large and small subunit of hydroquinone dioxygenase from Pseudomonas fluorescens strain ACB, respectively. This heterotetrameric enzyme is the first of its kind found in a strain of the genus Sphingomonas sensu latu
NOEnet–Use of NOE networks for NMR resonance assignment of proteins with known 3D structure
Motivation: A prerequisite for any protein study by NMR is the assignment of the resonances from the 15N−1H HSQC spectrum to their corresponding atoms of the protein backbone. Usually, this assignment is obtained by analyzing triple resonance NMR experiments. An alternative assignment strategy exploits the information given by an already available 3D structure of the same or a homologous protein. Up to now, the algorithms that have been developed around the structure-based assignment strategy have the important drawbacks that they cannot guarantee a high assignment accuracy near to 100%
A comparative co-simulation analysis to improve the sustainability of cogeneration-based district multi-energy systems using photovoltaics, power-to-heat, and heat storage
For an extensive decarbonization of district multi-energy systems, efforts are needed that go beyond today\u27s cogeneration of heat and power in district multi-energy systems. The multitude of existing technical possibilities are confronted with a large variety of existing multi-energy system configurations. The variety impedes the development of universal decarbonization pathways. In order to tackle the decarbonization challenge in existing and distinct districts, this paper calculates a wide range of urban district configurations in an extensive co-simulation based on domain specific submodels. A district multi-energy system comprising a district heating network, a power grid, and cogeneration is simulated for two locations in Germany with locally captured weather data, and for a whole year with variable parameters to configure a power-to-heat operation, building insolation/refurbishment, rooftop photovoltaic orientation, future energy demand scenarios, and district sizes with a temporal resolution of 60 seconds, in total 3840 variants.
The interdependencies and synergies between the electrical low-voltage distribution grid and the district heating network are analysed in terms of efficiency and compliance with network restrictions. Thus, important sector-specific simulations of the heat and the electricity sector are combined in a holistic district multi-energy system co-simulation.
The clearly most important impact on emission reduction and fuel consumption is a low heat demand, which can be achieved through thermal refurbishment of buildings. Up to \SI{46}{\percent} reduction in emissions are possible using the surplus electricity from photovoltaics for power-to-heat in combination with central heat storage in the district\u27s combined heat and power plant. Domestic hot water heated by district heating network in combination with power-to-heat conversion distributed in the district reduces the load on the distribution power grid. Even though the investigated measures already improve the sustainability significantly, providing the energy needed for the production of synthetic fuels remains the crucial challenge on the further path towards net-zero
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