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.

Models for the polarized parton distributions of the nucleon

Abstract: Polarized deep inelastic scattering (DIS) data are analyzed in leading and next-to-leading order of QCD within the common ``standard'' scenario of polarized parton distributions with a flavor-symmetric light sea (antiquark) distribution $\ensuremath{\delta}\overline{q},$ and a completely ${\mathrm{SU}(3)}_{f}$ broken ``valence'' scenario with totally flavor-asymmetric light sea densities $(\ensuremath{\delta}\ifmmode \bar{u}\else \={u}\fi{}\ensuremath{ e}\ensuremath{\delta}\overline{d}\ensuremath{ e}\ensuremath{\delta}\overline{s}).$ The latter flavor-broken light sea distributions are modeled with the help of a Pauli-blocking ansatz at the low radiative or dynamical input scales of ${\ensuremath{\mu}}_{\mathrm{LO}(\mathrm{NLO})}^{2}=0.26 (0.40){\mathrm{GeV}}^{2}$ which complies with predictions of the chiral quark-soliton model and expectations based on the statistical parton model as well as with the corresponding, well established, flavor-broken unpolarized sea $(\overline{d}g\ifmmode \bar{u}\else \={u}\fi{}).$ Present semi-inclusive DIS data cannot yet uniquely discriminate between those two flavor-symmetric and flavor-broken polarized light sea scenarios.

An endophytic fungus from Camptotheca acuminata that produces camptothecin and analogues

Abstract: The pentacyclic quinoline alkaloid camptothecin (1) is a potent antineoplastic agent. Two of its analogues, 9-methoxycamptothecin (2) and 10-hydroxycamptothecin (3), exhibit similar potency but do not have the potential therapeutic drawbacks produced by unmodified 1. We have established methodology for the isolation and unequivocal identification and characterization of a novel endophytic fungus isolated from the inner bark of the medicinal plant Camptotheca acuminata, which produced 1-3 in rich mycological medium (Sabouraud dextrose broth), under shake-flask fermentation conditions. The fungus was identified by its morphology and authenticated by ITS analysis (ITS1 and ITS2 regions and the intervening 5.8S rDNA region). Camptothecin (1) and its analogues were identified by 1H NMR spectroscopy and LC-HRMS and confirmed by comparison with authentic standards. The production pattern of the metabolites over seven successive subculture generations of this endophyte was studied. A sharp attenuation in the production of 1 and 2 was observed from the first- through to the seventh-generation subculture. Therefore, these results offer a caution as to the possibility of using endophytic fungi as alternate sources of plant secondary metabolite production. Further studies have been initiated on the analysis of the upstream metabolic intermediates to understand the steps at which the production of the metabolites in question is constrained.

scatterplot3d - An R Package for Visualizing Multivariate Data

Abstract: Scatterplot3d is an R package for the visualization of multivariate data in a three dimensional space. R is a "language for data analysis and graphics". In this paper we discuss the features of the package. It is designed by exclusively making use of already existing functions of R and its graphics system and thus shows the extensibility of the R graphics system. Additionally some examples on generated and real world data are provided.

Molecular Dynamic Simulations of Ionic Liquids: A Reliable Description of Structure, Thermodynamics and Dynamics

Abstract: The parameterization of a new force-field and its validation for the liquid description of five imidazolium-based ionic liquids [C(n)mim][NTf2] (n=1,2,4,6,8) are described. The proposed force-field is derived to reproduce densities, self-diffusion coefficients for cations and ions as well as NMR rotational correlation times for cations and water molecules in [C(2)mim][NTf2]. The temperature dependence and the cation chain-length dependence of these properties is described well. Very good agreement between simulated and experimental values for the heats of vaporization, shear viscosities and NMR rotational correlation times is also achieved. All properties are crucial for understanding the nature and interaction of ionic liquids. The good performance of the new force-field suggests that the Lennard-Jones interactions previously were strongly overestimated. The given force-field now allows us to investigate other important properties of this class of ionic liquids such as the micro segregation of ionic liquids, ion pair formation, lifetimes of ion pairs and the solvent dependency of these properties.

Internal Circulation within the Liquid Slugs of a Liquid-Liquid Slug-Flow Capillary Microreactor

Abstract: A so-called “slug-flow” capillary microreactor has been proposed for the investigation of mass-transfer-limited liquid−liquid reactions. Internal circulation within the slug leads to an intensified and tunable mass transfer. Understanding the development of the circulatory flows and the influence of operating parameters upon them is thus crucial. In this study, experiments were carried out to visualize the internal circulations using particle image velocimetry (PIV) technique. State-of-the-art computational fluid dynamics (CFD) simulations were used to predict the internal circulation within the liquid slugs and a CFD particle tracing algorithm employed to visualize them. Each slug was modeled as a distinct single-phase flow domain. The effect of the flow velocity and slug length on the velocity profile and stagnant zones of the internal circulations for a slug with and without a wall film is discussed. The internal circulations could be qualitatively and quantitatively characterized with the help of the ...