76 Works

A calibration strategy for LA-ICP-MS using isotope dilution for solid reference materials

J. P. Thieleke & C. Vogt
An isotope dilution method for the quantitative analysis of trace elements in biological samples and for the characterization of reference materials for the analysis of biological samples by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-ID-MS) has been tested. Polymeric thin layers with 5–10 μm thickness containing the ID-spike and the correction standard were produced by knife application onto polyester substrates. For the ID experiments 204Pb enriched lead was used, and bismuth served as the internal standard....

Subaquatisch-gravitativ umgelagerte Sedimente des Devons und Karbons um Bad Lauterberg (SW-Harz)

Sabine Hahlbeck
Aus dem SW-Harz werden Ton-/SiItsteine mit Einlagerungen aus verschiedenartigen und -alten Gesteinen beschrieben. Die Sedimentkörper werden aufgrund eindeutig submarin-gravitativer Umlagerungsgefüge als Olisthostrome eingestuft. Andere Strukturen innerhalb der Olisthostrome können auch diagenetisch oder tektonisch bedingt sein. Es werden drei verschiedene Olisthostromkomplexe ausgegliedert, die voneinander durch unterschiedliche Klastenführung abgegrenzt werden. Neben Olisthostromen stehen im Untersuchungsgebiet auch slumps und Steinschlagsedimente an.

Influence of Heat Treatment on the Degradation Behaviour of Degradable Magnesium Based Implants

Katja Bracht, Nina Angrisani, J. Seitz, S. Besdo & Janin Reifenrath
Aim of the study was to characterise the influence of heat treatment on the degradation behaviour and stability of degradable magnesium based implants. For this purpose two groups (untreated/ heat treated) of LAE442 pins were separately analysed in an in vitro and in vivo study. The corrosion behaviour was evaluated during 8 weeks degradation in SBF (in vitro) and 48 weeks degradation intramedullary in the rabbit tibia (in vivo). The analyses were made by using...

[Review untitled to: Leon de Stadler and Christoph Eyrich (eds.): Issues in Cognitive Linguistics. 1993 Proceedings of the International Cognitive Linguistics Conference]

Rainer Schulze
Review to: Leon de Stadler and Christoph Eyrich (eds.): Issues in Cognitive Linguistics. 1993 Proceedings of the International Cognitive Linguistics Conference. - Berlin : Walter de Gruyter, 1999. ISBN 978-3-11-015219-7

Well-posedness, blow-up phenomena, and global solutions for the b-equation

Joachim Escher & Zhaoyang Yin
In the paper we first establish the local well-posedness for a family of nonlinear dispersive equations, the so called b-equation. Then we describe the precise blow-up scenario. Moreover, we prove that for the b-equation we do have the coexistence of global in time solutions and blow-up phenomena: Depending on the initial data solutions may exist for ever, while other data force the solution to produce a singularity in finite time. Finally, we prove the uniqueness...

Proof of Concept of a New Glucose Sensing Technology: Color-Changing Hydrogels Including au Nanoparticles

C. Esch, A. Galperin, Benjamin Krolitzki, Birgit Glasmacher, A. Shen & B.D. Ratner
This Master thesis provides a proof of concept for a novel, implantable continuous glucose sensing technology. Immobilized glucose oxidase in a poly 2-hydroxyethyl methacrylate hydrogel is used to enzymatically convert an increase in glucose level to a local decrease in pH, which leads to a swelling of the hydrogel. Encapsulated gold nanoparticles in the gel allow an optical readout of the glucose concentration. Experimental methods include hydrogel synthesis, nanoparticle encapsulation and finally glucose sensing with...

Solving Biocompatibility Layer by Layer: Designing Scaffolds for Tissues

Holger Zernetsch, Alexandros Repanas, Oleksandr Gryshkov, Fedaa Al Halabi, Tim Rittinghaus, Soenke Wienecke, Marc Müller & Birgit Glasmacher
New opportunities for the design of artificial tissue structures via ice templating and electrospinning are described. Exemplarily, developments of vascular grafts, heart valves and nerve guides will be presented.

Conformational studies on Arabidopsis sulfurtransferase AtStr1 with spectroscopic methods

Andrea Bartels, Fabio Forlani, Silvia Pagani & Jutta Papenbrock
Sulfurtransferases/rhodaneses (Str) are enzymes widely distributed in archaea, prokaryota and eukaryota, and catalyze the transfer of sulfur from a donor molecule to a thiophilic acceptor substrate. In this reaction, Str cycles between the sulfur-free and the sulfur-substituted form. Two-domain Str consist of two globular domains of nearly identical size and conformation connected by a short linker sequence, which is elongated in plant two-domain Str proteins compared to Str in other organisms. The two-domain Arabidopsis thaliana...

Nanoporous Silica Films as Novel Biomaterial: Applications in the Middle Ear

Peter Behrens, Nina Ehlert, Peter Paul Müller, Martin Stieve & Thomas Lenarz
We have introduced nanoporous silica as a novel biomaterial. Nanoporous silica is non-toxic and biocompatible. It provides a high surface area and pore volume, uniform and tunable pore sizes and the possibility for chemical modification. We have shown that nanoporous silica coatings on middle ear prostheses provide a suitable basis for installing various functionalizations which can improve the healing after the insertion of the implant.

Nanoporous silica coatings on implant surfaces: characterization, stability, biocompatibility and drug release properties

Nina Ehlert, Tammo Lüßenhop, Ilka Krüger, Armin Feldhoff, Muhammad Badar, Peter P. Müller, Martin Stieve, Thomas Lenarz & Peter Behrens
Nanoporous silica coatings for drug release purposes were prepared on medical implants. As substrate, we chose Bioverit® II, which is a commercial available glass-mica ceramic implant material. The coating was prepared by a dip-coating technique in which long-chain organic molecules act as placeholders for the pores. Characterization of the coatings by scanning transmission electron microscopy and X-ray diffraction showed a disordered nanoporous system with a layer thickness of 30–150 nm. The nanoporous structure was stable...

Machine-assisted synthesis of modulators of the histone reader BRD9 using flow methods of chemistry and frontal affinity chromatography

Lucie Guetzoyan, Richard J. Ingham, Nikzad Nikbin, Julien Rossignol, Michael Wolling, Mark Baumert, Nicola A. Burgess-Brown, Claire M. Strain-Damerell, Leela Shrestha, Paul E. Brennan, Oleg Fedorov, Stefan Knapp & Steven V. Ley
A combination of conventional organic synthesis, remotely monitored flow synthesis and bioassay platforms, were used for the evaluation of novel inhibitors targeting bromodomains outside the well-studied bromodomain and extra terminal (BET) family, here exemplified by activity measurements on the bromodomain of BRD9 protein, a component of some tissue-specific SWi/SNF chromatin remodelling complexes. The Frontal Affinity Chromatography combined with Mass Spectrometry (FAC-MS) method proved to be reliable and results correlated well with an independent thermal shift...

*knuddel-zurueckknuddel-dich-ganzdollknuddel* : Inflektive und Inflektivkonstruktionen im Deutschen

Peter Schlobinski
In der Publikation geht es um Inflektive und Inflektivkonstruktionen im Deutschen.

Tuning excitability by alloying: the Rh(111)/Ni/H2 + O2 system

T. Smolinsky, M. Homann & R. Imbihl
The dynamic behavior of the O2 + H2 reaction on a Rh(111) surface alloyed with Ni has been studied in the 10(-5) mbar range using photoemission electron microscopy (PEEM) as a spatial resolving method. For T = 773 K and p(O2) = 5 x 10(-5) mbar the bifurcation diagram has been mapped out as a function of the Ni coverage in a range of 0 ML = Theta(Ni) >/= 1.3 ML. A critical Ni coverage...

Characterization of a highly efficient N-doped TiO 2 photocatalyst prepared via factorial design

Karen A. Borges, Lidiaine M. Santos, Roberto M. Paniago, Newton M. Barbosa Neto, Jenny Schneider, Detlef W. Bahnemann, Antonio Otavio T. Patrocinio & Antonio Eduardo H. Machado
The preparation of titanium dioxide nanoparticles doped with nitrogen for application as a photocatalyst in the decomposition of azo dyes was optimized by factorial planning. Five variables were evaluated and the results showed that the stirring method of the reaction medium, the nitrogen source and the calcination temperature are the determining parameters that affect the photocatalytic activity. With this methodology, it was possible to obtain an optimized photocatalyst (K1) with high surface area and high...

First structural characterization of Pa(iv) in aqueous solution and quantum chemical investigations of the tetravalent actinides up to Bk(IV): the evidence of a curium break

Nidhu Lal Banik, Valerie Vallet, Florent Real, Reda Mohamed Belmecheri, Bernd Schimmelpfennig, Jorg Rothe, Remi Marsac, Patric Lindqvist-Reis, Clemens Walther, Melissa A. Denecke & Christian M. Marquardt
More than a century after its discovery the structure of the Pa(4+) ion in acidic aqueous solution has been investigated for the first time experimentally and by quantum chemistry. The combined results of EXAFS data and quantum chemically optimized structures suggest that the Pa(4+) aqua ion has an average of nine water molecules in its first hydration sphere at a mean Pa-O distance of 2.43 A. The data available for the early tetravalent actinide (An)...

Enzymatic activity of the Arabidopsis sulfurtransferase resides in the C-terminal domain but is boosted by the N-terminal domain and the linker peptide in the full-length enzyme

M. Burow, D. Kessler & Jutta Papenbrock
Sulfurtransferases/rhodaneses are a group of enzymes widely distributed in plants, animals, and bacteria that catalyze the transfer of sulfur from a donor molecule to a thiophilic acceptor substrate. Sulfurtransferases (STs) consist of two globular domains of nearly identical size and conformation connected by a short linker sequence. In plant STs this linker sequence is exceptionally longer than in sequences from other species. The Arabidopsis ST1 protein (AJ131404) contains five cysteine residues: one residue is universally...

Technik statt Inhalt? Zu den Orientierungen von Stencil-Aktivisten

Christoph Pilz
Den Ausgangspunkt der Arbeit bilden die räumlichen Orientierungen von Stencil-Aktivisten. Wie wird der öffentliche Raum durch Street Artists angeeignet? Die Studie kommt in diesem Zusammenhang zu einem ganz unerwarteten Ergebnis. Die Praktiken sind stark auf die Technik der Stencilproduktion und -verbreitung fokussiert. Inhaltliche Ansprüche und Raumaneignung haben eine untergeordnete Relevanz.

An extracellular carboxylesterase from the basidiomycete Pleurotus sapidus hydrolyses xanthophyll esters

Holger Zorn, Henning Bouws, Meike Takenberg, Manfred Nimtz, Rita Getzlaff, Dietmar E. Breithaupt & Ralf Günter Berger
An extracellular enzyme capable of efficient hydrolysis of xanthophyll esters was purified from culture supernatants of the basidiomycete Pleurotus sapidus. Under native conditions, the enzyme exhibited a molecular mass of 430 kDa, and SDS-PAGE data suggested a composition of eight identical subunits. Biochemical characterisation of the purified protein showed an isoelectric point of 4.5, and ideal hydrolysis conditions were observed at pH 5.8 and 40 degrees C. Partial amino acid sequences were derived from N-terminal...

Zur Identifikation leerer Subjekte in infinitivischen Komplementsätzen – ein semantisch-pragmatisches Modell

Klaus-Michael Köpcke & Klaus-Uwe Panther
The interpretation of empty elements, i.e. signs that have no phonetic realization, constitutes a "classical" problem in modern linguistics. Null elements have been postulated on various levels of the linguistic system and its pragmatic use, in particular, in morphology and syntax. An adequate theory of discourse comprehension also requires an account of what is not said but only conversationally implicated. In the last thirty years the interpretation of empty subjects in non-finite clauses, which is...

Die sogenannte i-Derivation in der deutschen Gegenwartssprache : Ein Fall für output-orientierte Wortbildung

Klaus-Michael Köpcke
This paper deals with the currently very productive process of i-formation in German. It is argued that in forming i-derived words speakers try to instantiate as closely as possible a specific schema with attributes such as the following: trochaic word structure with the unstressed final segment i, masculine gender assignment, human, and hypocoristic/pejorative meaning. The prototypical instances are defined by a maximal number of attributes. Consequently, a distinction has to be made between central and...

Sprache oder Sprachform zu einer Theorie der Schriftlichkeit

Otto Ludwig
Schriftlichkeit kann unter verschiedenen Gesichtspunkten untersucht werden: historischen, kulturwissenschaftlichen, soziologischen, psychologischen, pädagogischen und selbstverständlich auch linguistischen. Im folgenden soll es ausschließlich um linguistisch relevante Aspekte von Schriftlichkeit gehen.

Der Verdacht des Bagatelldiebstahls im Arbeitsrecht – Das sog. Pfandbonurteil

Claudia Keiser
Bagatellkriminalität und Unschuldsvermutung sind zwei Themenkomplexe, die zwar ursprünglich im Strafrecht verortet sind. Dass sie selbstverständlich gleichwohl auch im zivil- bzw. arbeitsrechtlichen Kontext relevant werden können, zeigt sich immer dann, wenn um die Wirksamkeit einer wegen einer solchen Bagatelltat ausgesprochenen Verdachtskündigung gestritten wird. Der Beitrag nimmt das Urteil des LArbG Berlin-Brandenburg gegen »Emily« zum Anlass, einerseits gegen eine »strafrechtliche Erheblichkeitsschwelle im Arbeitsrecht« zu argumentieren, andererseits aber die Bedeutung der Unschuldsvermutung im Arbeitsrecht hervorzuheben.

Comparison between simulation results and DEXA investigation of the bone remodelling after implanting a cementless long stem hip prosthesis

Amer Almohallami, Anas Bouguecha, Christina Stukenborg-Colsman, M. Lerch, I. Nolte & Bernd-Arno Behrens
Bone remodelling around a femoral prosthesis is one of the main reasons of aseptic loosening of the implant’s stem. The difference in stiffness between the bone tissue and the prosthesis leads to unload the periprosthetic bone and thus to decrease the bone mineral density (BMD), which is known as stress shielding. This paper represents a comparison between measured changes in (BMD) in a periprosthetic Femur with a cementless Bicontact stem by prospective dualenergy X-ray absorptiometry...

Entwicklung von schichtweise ausgerichteten Faserverbundstrukturen

Tim Rittinghaus, Holger Zernetsch & Birgit Glasmacher
Jedes Jahr müssen tausende defekte Herzklappen ersetzt werden. Die Verwendung von biologischen oder mechanischen Prothesen macht aufgrund der Tatsache, dass diese nicht mitwachsen, gerade bei Heranwachsenden regelmäßige Reimplantationen erforderlich. Eine mögliche Alternative sind Klappenprothesen bestehend aus einer Gerüststruktur, welche mit körpereigenen Zellen besiedelt wird. Das Gerüst wird im Laufe der Zeit vollständig durch lebendes Gewebe ersetzt. Ziel dieser Diplomarbeit ist die Herstellung von schichtweise ausgerichteten Faserverbundstrukturen, um zukünftig den aus mehreren Gewebeschichten bestehenden Aufbau der...

Optimization of a test setup for examining blood damage caused by high shear forces

Rieke Kortlepel, Benjamin Krolitzki, Marc Müller & Birgit Glasmacher
If blood pumps are applied in the human body or extracorporeal, blood damage can be caused by shear forces that act on the blood during the delivery. For an accelerated development of blood pumps with help of simulations there is a need for reliable limit values for shear forces. To determine these limit values a shear force test setup was built at the Institute for Multiphase Processes. In the context of the presented master thesis...

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