Majorana bound state localization and energy oscillations for magnetic impurity chains on conventional superconductors

We study a chain of magnetic impurities on a conventional superconductor with spin-orbit coupling, treating the superconducting order fully self-consistently. We find and quantify strong hybridization between the topological edge Majorana bound states (MBSs) and in-gap Yu-Shiba-Rusinov (YSR) states, which causes increasing energy oscillations as a function of magnetic impurity strength, even when the direct MBS overlap is negligible. By treating the MBS as a topological boundary state, dependent only on the effective mass gap, we arrive at a fully parameter-free functional form of the its localization which decreases with magnetic impurity strength, opposite to the behavior of the superconducting coherence length.Comment: 7 pages, 5 figure

High-resolution surface plasmon imaging of gold nanoparticles by energy-filtered transmission electron microscopy

We demonstrate the imaging capabilities of energy-filtered transmission electron microscopy at high-energy resolution in the low-energy-loss region, reporting the direct image of a surface plasmon of an elongated gold nanoparticle at energies around 1 eV. Using complimentary model calculations performed within the boundary element method approach we can assign the observed results to the plasmon eigenmodes of the metallic nanoparticle

Business Model Configurations for Digital Platform Success - Towards a Typology of Digital Platform Business Models

Competition between digital platforms is harder compared to non-platform businesses. Fierce platform competition reduces digital platforms’ chances of success. Research has identified many aspects of digital platforms and their surrounding ecosystem that influence the success of digital platforms. This research is comprehensive but not integrated. The business model as an activity system provides a lens to orchestrate various dimensions of digital platforms. We conduct a case survey of published case studies on digital platforms and analyze their business models using a multi-value qualitative comparative analysis. The resulting business model configurations reveal how surviving digital platforms combine different value propositions, value capture mechanisms, and value creation strategies. We identify four configurations of digital platform business models (matching, spreading, innovating, and dominating business models) leading to digital platform success (i.e., survival). In our future research, we will identify more detailed business model configurations using a larger case sample

Unexplored Character Diversity in Onychophora (Velvet Worms): A Comparative Study of Three Peripatid Species

Low character variation among onychophoran species has been an obstacle for taxonomic and phylogenetic studies in the past, however we have identified a number of new and informative characters using morphological, molecular, and chromosomal techniques. Our analyses involved a detailed examination of Epiperipatus biolleyi from Costa Rica, Eoperipatus sp. from Thailand, and a new onychophoran species and genus from Costa Rica, Principapillatus hitoyensisgen. et sp. nov.. Scanning electron microscopy on embryos and specimens of varying age revealed novel morphological characters and character states, including the distribution of different receptor types along the antennae, the arrangement and form of papillae on the head, body and legs, the presence and shape of interpedal structures and fields of modified scales on the ventral body surface, the arrangement of lips around the mouth, the number, position and structure of crural tubercles and anal gland openings, and the presence and shape of embryonic foot projections. Karyotypic analyses revealed differences in the number and size of chromosomes among the species studied. The results of our phylogenetic analyses using mitochondrial COI and 12S rRNA gene sequences are in line with morphological and karyotype data. However, our data show a large number of unexplored, albeit informative, characters in the Peripatidae. We suggest that analysing these characters in additional species would help unravel species diversity and phylogeny in the Onychophora, and that inconsistencies among most diagnostic features used for the peripatid genera in the literature could be addressed by identifying a suite of characters common to all peripatids.This study was supported by a Ph.D. fellowship of the Conselho Nacional de Desenvolvimento Cientı´fico e Tecnolo´gico (CNPq: 290029/2010-4) and by a SYNTHESYS grant (financed by the European Community Research Infrastructure Action - FP7 Integrating Activities Programme: http://www.synthesys.info/) to ISO. GM is a Research Group Leader supported by the Emmy Noether Programme of the German Research Foundation (DFG: Ma 4147/3-1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Multi-Parameter Fluorescence Detection at the Single-Molecule Level : Techniques and Applications

Fluorescence-based assays using single-molecule techniques are evolving into a very important tool in science. These techniques include not only direct detection and analysis of single-molecule events, but also spectroscopic analysis through fluctuation methods such as FCS (fluorescence correlation spectroscopy) or FIDA (fluorescence intensity distribution analysis). What are the advantages of these techniques and why is fluorescence chosen as the readout? This article will give an overview of fluorescence techniques and applications of single-molecule detection and analysis. It is focused on the detection of fluorescence emitted from freely diffusing molecules in solution. A confocal microscope is described, which uses special electronics for detection and enables the observation of fluorescence emission from single molecules along with monitoring of various fluorescence parameters (MFD). In the first part, procedures such as the detection and identification of single molecules, the monitoring of rare events, the direct temporal observation of binding events and conformational dynamics, as well as the possibility of selective spectroscopy of molecular states are described. Industrial applications such as HTS are illustrated by a description of using fluctuation methods such as FCS and FIDA to resolve characteristic properties of biological assays, e.g., ligand-protein and -vesicle binding or enzymatic reactions

Detoxifying Escherichia coli for endotoxin-free production of recombinant proteins

Es va publicar un treball amb esmenes a aquest article que es pot consultar a https://ddd.uab.cat/record/185349 (DOI 10.1186/s12934-015-0265-x)Background: lipopolysaccharide (LPS), also referred to as endotoxin, is the major constituent of the outer leaflet of the outer membrane of virtually all Gram-negative bacteria. The lipid A moiety, which anchors the LPS molecule to the outer membrane, acts as a potent agonist for Toll-like receptor 4/myeloid differentiation factor 2-mediated pro-inflammatory activity in mammals and, thus, represents the endotoxic principle of LPS. Recombinant proteins, commonly manufactured in Escherichia coli, are generally contaminated with endotoxin. Removal of bacterial endotoxin from recombinant therapeutic proteins is a challenging and expensive process that has been necessary to ensure the safety of the final product. -Results: as an alternative strategy for common endotoxin removal methods, we have developed a series of E. coli strains that are able to grow and express recombinant proteins with the endotoxin precursor lipid IVA as the only LPS-related molecule in their outer membranes. Lipid IVA does not trigger an endotoxic response in humans typical of bacterial LPS chemotypes. Hence the engineered cells themselves, and the purified proteins expressed within these cells display extremely low endotoxin levels. - Conclusions: this paper describes the preparation and characterization of endotoxin-free E. coli strains, and demonstrates the direct production of recombinant proteins with negligible endotoxin contamination

Observing the oceanic heat flux toward retreating outlet glaciers in NE-Greenland

Warming of subsurface water of Atlantic origin has been suggested to be a major driver of the ongoing retreat of marine terminating glaciers around the coast of Greenland. In recent years, also the outlet glaciers of the Northeast Greenland Ice Stream have undergone major changes leading to an increased mass flux from the ice sheet into the ocean. Both, the thinning of the 80-km long floating tongue of the 79 North Glacier and the collapse of the floating tongue of the adjacent Zachariæ Isstrøm have been attributed to increasing ocean temperatures. However, it has been unclear whether the bathymetry was sufficiently deep to allow warm Atlantic water to reach Zachariæ Isstrøm. Here we report on the first station-based bathymetric and oceanographic measurements carried out in summers 2016 and 2017 close to the calving front of Zachariæ Isstrøm. They reveal 1°C-warm waters of Atlantic origin in a layer between 300 to 600-m depth to be in direct contact with the calving front of the glacier. Also, 12-month long mooring based observations demonstrate Atlantic origin waters to flush the cavity beneath the 79 North Glacier causing high basal melt rates along the 80-km-long glacier base. Based on moored measurements further offshore on the Northeast Greenland continental shelf we discuss the processes that govern the oceanic heat transport toward both glaciers. A better understanding of these processes is relevant to distinguish short-term variability from long-term changes in the oceanic heat flux toward the glaciers

MNPBEM - A Matlab toolbox for the simulation of plasmonic nanoparticles

MNPBEM is a Matlab toolbox for the simulation of metallic nanoparticles (MNP), using a boundary element method (BEM) approach. The main purpose of the toolbox is to solve Maxwell's equations for a dielectric environment where bodies with homogeneous and isotropic dielectric functions are separated by abrupt interfaces. Although the approach is in principle suited for arbitrary body sizes and photon energies, it is tested (and probably works best) for metallic nanoparticles with sizes ranging from a few to a few hundreds of nanometers, and for frequencies in the optical and near-infrared regime. The toolbox has been implemented with Matlab classes. These classes can be easily combined, which has the advantage that one can adapt the simulation programs flexibly for various applications.Comment: to appear in Comp. Phys. Commun.; see also http://physik.uni-graz.at/~uxh/mnpbem/mnpbem.htm