42 research outputs found

    Establishing a Comprehensive Toolbox for Isotopic Labelling Studies on Terpene Synthases

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    The cumulative doctoral thesis "Establishing a Comprehensive Toolbox for Isotopic Labelling Studies on Terpene Synthases" describes the synthesis and application of isotopically labelled compounds for the systematic in vitro investigation of recombinant terpene synthases to target both cyclisation mechanism and product structure. Methodically, the known approach of enantioselectively deuterated oligoprenyl diphosphate substrates was further developed by the addition of 13C-labelling, which led to a more sensitive detection of the labelled product by NMR. With a stereochemical anchor of known absolute configuration installed in the substrate and untouched by the enzymatic cyclisation mechanism, it is possible to infer the absolute configuration of the terpene product by following the incorporation of deuterium into the diastereotopic hydrogen positions. By combining chemical and enzymatic synthesis, it was finally possible to label every methylene group of the common terpene precursors by 13C and 2H in an enantioselective fashion. These extensions improve both feasibility and robustness of this method, which contributes to the challenging structure elucidation of terpene natural products, including their difficult to address absolute configurations. Depending on the cyclisation mechanism, also the stereochemical course of hydrogen movements can be delineated. Connected to the expanding labelling possibilities, several newly identified terpene synthases from bacteria and fungi have been addressed covering various aspects of their catalysis such as substrate or product specificity, repetitive mechanistic motifs and stereochemical issues. The structural variety of the known and newly identified natural products thereby inspired further studies like tailored labelling experiments, site-directed mutagenesis, chemical modifications and the investigation of EI-MS fragmentation mechanisms. With few publications dealing with other aspects of natural product chemistry such as fungal aromatic volatiles, lignin degradation and selected aspects of the secondary metabolism of marine Roseobacter group bacteria also being included in this work, the main focus lays on a deepened understanding of terpene synthase reactions. The isotopically labelled substrates introduced in this study thereby represent a valuable experimental tool towards a comprehensive picture of these astonishing enzymes that create the largest group of natural products

    Metabolic Network Model Identification-Parameter Estimation and Ensemble Modeling

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    Ph.DDOCTOR OF PHILOSOPH

    Power Electronics Applications in Renewable Energy Systems

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    The renewable generation system is currently experiencing rapid growth in various power grids. The stability and dynamic response issues of power grids are receiving attention due to the increase in power electronics-based renewable energy. The main focus of this Special Issue is to provide solutions for power system planning and operation. Power electronics-based devices can offer new ancillary services to several industrial sectors. In order to fully include the capability of power conversion systems in the network integration of renewable generators, several studies should be carried out, including detailed studies of switching circuits, and comprehensive operating strategies for numerous devices, consisting of large-scale renewable generation clusters

    Applications of MATLAB in Science and Engineering

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    The book consists of 24 chapters illustrating a wide range of areas where MATLAB tools are applied. These areas include mathematics, physics, chemistry and chemical engineering, mechanical engineering, biological (molecular biology) and medical sciences, communication and control systems, digital signal, image and video processing, system modeling and simulation. Many interesting problems have been included throughout the book, and its contents will be beneficial for students and professionals in wide areas of interest

    Multiscale modeling of metal nanoparticles for biotechnological applications

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    Functionalized metal nanoparticles are supramolecular assemblies that are gaining increasing attention in biomedicine due to their broad-spectrum applicability. In this context, understanding the nano-biointerface is critical for implementing nanoparticles into medical practices, yet the structure-function relation of functionalized metal nanoparticles remains puzzling. This work discusses the design of metal nanoparticles with targeted applications from three focal points: structural modeling, method development, and biomolecular interactions. First, the NanoModeler webserver is introduced for the standardized building and parametrizing of metal nanoparticles for simulations at atomistic and coarse-grained resolutions. Second, a theoretical model is formulated to characterize the surface of charged nanoparticles, which, when combined with mesoscale simulations, clarifies the fundamental principles that enable colloidal stability at physiological conditions. Third, atomistic and coarse-grained simulations were combined to describe, at the molecular level, the non- disruptive cellular permeabilization induced by membranotropic nanoparticles to facilitate intracellular cargo delivery. The multilayered work presented here comprehends new online tools, physics-based methods, and molecular insights that expand our understanding of the structure-function relation in metal nanoparticles and contribute to the design of safe and effective nanoparticle-based therapeutic agents

    The conceptual design of a small solar probe /Sunblazer/

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    Conceptual design of Sunblazer space probe for determining electron density of solar coron

    MC 2019 Berlin Microscopy Conference - Abstracts

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    Das Dokument enthält die Kurzfassungen der Beiträge aller Teilnehmer an der Mikroskopiekonferenz "MC 2019", die vom 01. bis 05.09.2019, in Berlin stattfand

    NASA Tech Briefs, July 1997

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    Topics: Mechanical Components; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Software; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Life Sciences

    Concepts, Frames and Cascades in Semantics, Cognition and Ontology

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    This open access book presents novel theoretical, empirical and experimental work exploring the nature of mental representations that support natural language production and understanding, and other manifestations of cognition. One fundamental question raised in the text is whether requisite knowledge structures can be adequately modeled by means of a uniform representational format, and if so, what exactly is its nature. Frames are a key topic covered which have had a strong impact on the exploration of knowledge representations in artificial intelligence, psychology and linguistics; cascades are a novel development in frame theory. Other key subject areas explored are: concepts and categorization, the experimental investigation of mental representation, as well as cognitive analysis in semantics. This book is of interest to students, researchers, and professionals working on cognition in the fields of linguistics, philosophy, and psychology

    The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry

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    The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry was held on 1–15 July 2021. The scope of this online conference was to gather experts that are well-known worldwide who are currently working in chemical sensor technologies and to provide an online forum for the presention and discussion of new results. Throughout this event, topics of interest included, but were not limited to, the following: electrochemical devices and sensors; optical chemical sensors; mass-sensitive sensors; materials for chemical sensing; nano- and micro-technologies for sensing; chemical assays and validation; chemical sensor applications; analytical methods; gas sensors and apparatuses; electronic noses; electronic tongues; microfluidic devices; lab-on-a-chip; single-molecule sensing; nanosensors; and medico-diagnostic testing
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