Technical University of Dortmund

About: Technical University of Dortmund is a education organization based out in Dortmund, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Context (language use) & Large Hadron Collider. The organization has 13028 authors who have published 27666 publications receiving 615557 citations. The organization is also known as: Dortmund University & University of Dortmund.

Superradiance and subradiance in an inhomogeneously broadened ensemble of two-level systems coupled to a low-Q cavity.

Abstract: The collective spontaneous emission of a fully inverted inhomogeneously broadened ensemble of $N$ two-level systems coupled to a single-mode low-$Q$ cavity is investigated numerically using Monte Carlo wave function technique. An intrinsically bi-exponential emission dynamics is found when the time scales of superradiance ${\ensuremath{\tau}}_{\mathrm{sr}}$ and inhomogeneous dephasing ${T}_{2}^{*}\ensuremath{\sim}1/\ensuremath{\Delta}{\ensuremath{\omega}}_{\mathrm{inh}}$ become comparable: a fast superradiant is followed by a slow subradiant decay. Experimental configurations using ensembles of quantum dots coupled to optical microcavities are proposed as possible candidates to observe the combined superradiant and subradiant energy relaxation.

High-Capacity Hierarchically Imprinted Polymer Beads for Protein Recognition and Capture

Abstract: Key life science disciplines (e.g. diagnostics, proteomics, protein purification) rely on selective protein binders that serve the purpose of specifically capturing a protein in a complex matrix for either analytical or preparative use. These binders are commonly of biological origin, for example, antibodies for protein fractionation or detection in proteomics or antibody-binding proteins (e.g. Protein A) for antibody capture in downstream processing. Common to most biologically derived protein binders are their lability, high cost, denaturation tendency, and intrinsically low binding capacity. Robust artificial protein binders in the form of molecularly imprinted polymers (MIPs) could potentially overcome these limitations, thus offering a step change in the above disciplines. In spite of numerous reports that describe protein-imprinted hydrogels, advances towards generic and robust imprinting techniques have been slow. One reason is the need for employing a low cross-linking level in order to provide a mesh size of the network large enough for the protein to penetrate. The memory effects of these gels are thus easily erased, thereby preventing repeated use of the gels. Various forms of surface-imprinting techniques have been used with promising results to address this problem. However, robust imprinting techniques that afford materials, which can compete with established bioaffinity media in terms of both affinity and capacity, are still lacking. By combining our previously developed hierarchical imprinting technique for small molecules with protein imprinting we herein demonstrate a general technique (Figure 1) to obtain protein-imprinted separation media that could potentially serve this purpose. As model proteins in this proof of concept study, the human blood plasma proteins,

Optical investigation of the natural electron doping in thin MoS2 films deposited on dielectric substrates.

Abstract: Two-dimensional (2D) compounds provide unique building blocks for novel layered devices and hybrid photonic structures. However, large surface-to-volume ratio in thin films enhances the significance of surface interactions and charging effects requiring new understanding. Here we use micro-photoluminescence (PL) and ultrasonic force microscopy to explore the influence of the dielectric environment on optical properties of a few monolayer MoS2 films. PL spectra for MoS2 films deposited on SiO2 substrates are found to vary widely. This film-to-film variation is suppressed by additional capping of MoS2 with SiO2 and SixNy, improving mechanical coupling of MoS2 with surrounding dielectrics. We show that the observed PL non-uniformities are related to strong variation in the local electron charging of MoS2 films. In completely encapsulated films, negative charging is enhanced leading to uniform optical properties. Observed great sensitivity of optical characteristics of 2D films to surface interactions has important implications for optoelectronics applications of layered materials.

Tropane Alkaloids: Chemistry, Pharmacology, Biosynthesis and Production.

Abstract: Tropane alkaloids (TA) are valuable secondary plant metabolites which are mostly found in high concentrations in the Solanaceae and Erythroxylaceae families. The TAs, which are characterized by their unique bicyclic tropane ring system, can be divided into three major groups: hyoscyamine and scopolamine, cocaine and calystegines. Although all TAs have the same basic structure, they differ immensely in their biological, chemical and pharmacological properties. Scopolamine, also known as hyoscine, has the largest legitimate market as a pharmacological agent due to its treatment of nausea, vomiting, motion sickness, as well as smooth muscle spasms while cocaine is the 2nd most frequently consumed illicit drug globally. This review provides a comprehensive overview of TAs, highlighting their structural diversity, use in pharmaceutical therapy from both historical and modern perspectives, natural biosynthesis in planta and emerging production possibilities using tissue culture and microbial biosynthesis of these compounds.