Subleading Regge limit from a soft anomalous dimension

Wilson lines capture important features of scattering amplitudes, for example soft effects relevant for infrared divergences, and the Regge limit. Beyond the leading power approximation, corrections to the eikonal picture have to be taken into account. In this paper, we study such corrections in a model of massive scattering amplitudes in N = 4 super Yang-Mills, in the planar limit, where the mass is generated through a Higgs mechanism. Using known three-loop analytic expressions for the scattering amplitude, we find that the first power suppressed term has a very simple form, equal to a single power law. We propose that its exponent is governed by the anomalous dimension of a Wilson loop with a scalar inserted at the cusp, and we provide perturbative evidence for this proposal. We also analyze other limits of the amplitude and conjecture an exact formula for a total cross-section at high energies.Comment: 19 pages, several appendices, many figure

Twin-Arginine translocation-Arresting protein regions contact TatA and TatB

Tat systems translocate folded proteins across biological membranes of prokaryotes and plant plastids. TatBC complexes recognize N-Terminal Tat signal peptides that contain a sequence motif with two conserved arginines (RR-Motif), and transport takes place after a recruitment of TatA. Unfolded Tat substrate domains lower translocation efficiency and too long linkers lead to translocation arrest. To identify the components that interact with transported proteins during their passage through the translocon, we used a Tat substrate that arrests translocation at a long unfolded linker region, and we chose in vivo site-Directed photo cross-Linking to specifically detect the interactions of this linker region. For comparison, we included the interactions of the signal peptide and of the folded domain at the C-Terminus of this construct. The data show that the linker contacts only two, structurally similar Tat components, namely TatA and TatB. These contacts depend on the recognition of the Tat-Specific signal peptide. Only when membrane translocation of the globular domain was allowed - i.e., in the absence of the linker - we observed the same TatAB-Contacts also to the globular domain. The data thus suggest that mature protein domains are translocated through a TatAB environment

The Tat-dependent protein translocation pathway

The twin-arginine translocation (Tat) pathway is found in bacteria, archaea, and plant chloroplasts, where it is dedicated to the transmembrane transport of fully folded proteins. These proteins contain N-terminal signal peptides with a specific Tat-system binding motif that is recognized by the transport machinery. In contrast to other protein transport systems, the Tat system consists of multiple copies of only two or three usually small (∼8-30 kDa) membrane proteins that oligomerize to two large complexes that transiently interact during translocation. Only one of these complexes includes a polytopic membrane protein, TatC. The other complex consists of TatA. Tat systems of plants, proteobacteria, and several other phyla contain a third component, TatB. TatB is evolutionarily and structurally related to TatA and usually forms tight complexes with TatC. Minimal two-component Tat systems lacking TatB are found in many bacterial and archaeal phyla. They consist of a 'bifunctional' TatA that also covers TatB functionalities, and a TatC. Recent insights into the structure and interactions of the Tat proteins have various important implications. © 2011 by Walter de Gruyter Berlin Boston 2011

DECONVOLUTION-BASED PHYSIOLOGICAL SIGNAL SIMPLFICATION FOR PERIODICAL PARAMETER ESTIMATION

The estimation of physiological parameters from raw sensor signals is absolutely crucial in modern clinical applications. A wide variety of these parameters incorporate a periodic nature, such as the heart rate or the respiration rate. This property can be exploited for their estimation. Particularly challenging is the processing of novel, unobtrusive measurement techniques, which are characterized by complex, time-varying waveforms. Simple peak detection algorithms are often not suited for these applications. One way to tackle these challenges is a preprocessing step for the simplification of the physiological signals. A novel deconvolution based approach for this preprocessing is introduced and evaluated in this paper. Two deconvolution methods are regarded, the “Minimum Entropy Deconvolution” (MED) and the “Maximum Correlated Kurtosis Deconvolution” (MCKD). Important parameters are outlined and examined. Finally, the methods are validated using artificial as well as real clinical signals to demonstrate their potential

Microwave plasma discharges for biomass pretreatment: Degradation of a sodium carboxymethyl cellulose model

Biogas production is an important component of an environmentally benign renewable energy strategy. However, the cost-effectiveness of biogas production from biomass is limited by the presence of polymeric structures, which are recalcitrant to digestion by bacteria. Therefore, pretreatments must often be applied prior to anaerobic fermentation to increase yields of biogas. Many physico-chemical pretreatments have a high energy demand and are generally costly. An alternative could be the ignition of a plasma directly in the biomass substrate. The reactive species that are generated by plasma-liquid interactions, such as hydroxyl radicals and hydrogen peroxides, could contribute significantly to the disintegration of cell walls and the breakage of poorly digestible polymers. With respect to economic, processing, and other potential benefits, a microwave instigated and sustained plasma was investigated. A microwave circuit transmitted 2-kW pulses into a recirculated sodium carboxymethyl cellulose solution, which mimicked the rheological properties of biomass. Each microwave pulse had a duration of 12.5 ms and caused the ignition of a discharge after a vapor bubble had formed. Microwaves were absorbed in the process with an efficiency of ∼97%. Slow-motion imaging showed the development of the discharge. The plasma discharges provoked a decrease in the viscosity, probably caused by the shortening of polymer chains of the cellulose derivative. The decrease in viscosity by itself could reduce processing costs and promotes bacterial activity in actual biomass. The results demonstrate the potential of microwave in-liquid plasma discharges for the pretreatment of biomass. © 2020 Author(s)

Using a dual plasma process to produce cobalt--polypyrrole catalysts for the oxygen reduction reaction in fuel cells -- part II: analysing the chemical structure of the films

The chemical structure of cobalt--polypyrrole -- produced by a dual plasma process -- is analysed by means of X-ray photoelectron spectroscopy (XPS), near edge X-ray absorption spectroscopy (NEXAFS), X-ray diffraction (XRD), energy-dispersive X-Ray spectroscopy (EDX) and extended x-ray absorption spectroscopy (EXAFS).It is shown that only nanoparticles of a size of 3\,nm with the low temperature crystal structure of cobalt are present within the compound. Besides that, cobalt--nitrogen and carbon--oxygen structures are observed. Furthermore, more and more cobalt--nitrogen structures are produced when increasing the magnetron power. Linking the information on the chemical structure to the results about the catalytic activity of the films -- which are presented in part I of this contribution -- it is concluded that the cobalt--nitrogen structures are the probable catalytically active sites. The cobalt--nitrogen bond length is calculated as 2.09\,\AA\ and the carbon--nitrogen bond length as 1.38\,\AA