633 Works

Plutonium release from Fukushima Daiichi fosters the need for more detailed investigations

Stephanie Schneider, Clemens Walther, Stefan Bister, Viktoria Schauer, Marcus Christl, Hans-Arno Synal, Katsumi Shozugawa & Georg Steinhauser
The contamination of Japan after the Fukushima accident has been investigated mainly for volatile fission products, but only sparsely for actinides such as plutonium. Only small releases of actinides were estimated in Fukushima. Plutonium is still omnipresent in the environment from previous atmospheric nuclear weapons tests. We investigated soil and plants sampled at different hot spots in Japan, searching for reactor-borne plutonium using its isotopic ratio Pu-240/Pu-239. By using accelerator mass spectrometry, we clearly demonstrated...

Numerical simulation of strain-adaptive bone remodelling in the ankle joint

Anas Bouguecha, Nelly Weigel, Bernd-Arno Behrens, Christina Stukenborg-Colsman & Hazibullah Waizy
Background: The use of artificial endoprostheses has become a routine procedure for knee and hip joints while ankle arthritis has traditionally been treated by means of arthrodesis. Due to its advantages, the implantation of endoprostheses is constantly increasing. While finite element analyses (FEA) of strain-adaptive bone remodelling have been carried out for the hip joint in previous studies, to our knowledge there are no investigations that have considered remodelling processes of the ankle joint. In...

Quantification of microbial communities in subsurface marine sediments of the Black Sea and off Namibia

Axel Schippers, Dagmar Kock, Carmen Hoeft, Gerrit Koeweker & Michael Siegert
Organic-rich subsurface marine sediments were taken by gravity coring up to a depth of 10 m below seafloor at six stations from the anoxic Black Sea and the Benguela upwelling system off Namibia during the research cruises Meteor 72-5 and 76-1, respectively. The quantitative microbial community composition at various sediment depths was analyzed using total cell counting, catalyzed reporter deposition fluorescence in situ hybridization (CARD FISH) and quantitative real-time PCR (Q-PCR). Total cell counts decreased...

Measurement of finite-frequency current statistics in a single-electron transistor

Niels Ubbelohde, Christian Fricke, Christian Flindt, Frank Hohls & Rolf J. Haug
Electron transport in nanoscale structures is strongly influenced by the Coulomb interaction that gives rise to correlations in the stream of charges and leaves clear fingerprints in the fluctuations of the electrical current. A complete understanding of the underlying physical processes requires measurements of the electrical fluctuations on all time and frequency scales, but experiments have so far been restricted to fixed frequency ranges, as broadband detection of current fluctuations is an inherently difficult experimental...

Do Children's Health Resources Differ According to Preschool Physical Activity Programmes and Parental Behaviour? A Mixed Methods Study

Elena Sterdt, Natalie Pape, Silke Kramer, Sebastian Liersch, Michael Urban, Rolf Werning & Ulla Walter
Preschool can have positive effects on the development of a healthy lifestyle. The present study analysed to what extent different conditions, structures and behavioural models in preschool and family-children's central social microsystems-can lead to differences in children's health resources. Using a cross-sectional mixed methods approach, contrast analyses of "preschools with systematic physical activity programmes" versus "preschools without physical activity programmes" were conducted to assess the extent to which children's physical activity, quality of life and...

Physiological and molecular analysis of the interaction between aluminium toxicity and drought stress in common bean (Phaseolus vulgaris)

Zhong-Bao Yang, Dejene Eticha, Alfonso Albacete, Idupulapati Madhusudana Rao, Thomas Roitsch & Walter Johannes Horst
Aluminium (Al) toxicity and drought are two major factors limiting common bean (Phaseolus vulgaris) production in the tropics. Short-term effects of Al toxicity and drought stress on root growth in acid, Al-toxic soil were studied, with special emphasis on Al-drought interaction in the root apex. Root elongation was inhibited by both Al and drought. Combined stresses resulted in a more severe inhibition of root elongation than either stress alone. This result was different from the...

Absorption Measurements of Periodically Poled Potassium Titanyl Phosphate (PPKTP) at 775 nm and 1550 nm

Jessica Steinlechner, Stefan Ast, Christoph Krueger, Amrit Pal Singh, Tobias Eberle, Vitus Haendchen & Roman Schnabel
The efficient generation of second-harmonic light and squeezed light requires non-linear crystals that have low absorption at the fundamental and harmonic wavelengths. In this work the photo-thermal self-phase modulation technique is exploited to measure the absorption coefficient of periodically poled potassium titanyl phosphate (PPKTP) at 1,550 nm and 775 nm. The measurement results are (84 +/- 40) ppm/cm and (127 +/- 24) ppm/cm, respectively. We conclude that the performance of state-of-the-art frequency doubling and squeezed...

Characterization of nanoparticle mediated laser transfection by femtosecond laser pulses for applications in molecular medicine

Markus Schomaker, Dag Heinemann, Stefan Kalies, Saskia Willenbrock, Siegfried Wagner, Ingo Nolte, Tammo Ripken, Hugo Murua Escobar, Heiko Meyer & Alexander Heisterkamp
Background: In molecular medicine, the manipulation of cells is prerequisite to evaluate genes as therapeutic targets or to transfect cells to develop cell therapeutic strategies. To achieve these purposes it is essential that given transfection techniques are capable of handling high cell numbers in reasonable time spans. To fulfill this demand, an alternative nanoparticle mediated laser transfection method is presented herein. The fs-laser excitation of cell-adhered gold nanoparticles evokes localized membrane permeabilization and enables an...

Influence of Cobalt on the Properties of Load-Sensitive Magnesium Alloys

Christian Klose, Christian Demminger, Gregor Mroz, Wilfried Reimche, Friedrich-Wilhelm Bach, Hans Jürgen Maier & Kai Kerber
In this study, magnesium is alloyed with varying amounts of the ferromagnetic alloying element cobalt in order to obtain lightweight load-sensitive materials with sensory properties which allow an online-monitoring of mechanical forces applied to components made from Mg-Co alloys. An optimized casting process with the use of extruded Mg-Co powder rods is utilized which enables the production of magnetic magnesium alloys with a reproducible Co concentration. The efficiency of the casting process is confirmed by...

AUXIN-BINDING-PROTEIN1 (ABP1) in phytochrome-B-controlled responses

Yunus Effendi, Alan M. Jones & Günther F.E. Scherer
The auxin receptor ABP1 directly regulates plasma membrane activities including the number of PIN-formed (PIN) proteins and auxin efflux transport. Red light (R) mediated by phytochromes regulates the steady-state level of ABP1 and auxin-inducible growth capacity in etiolated tissues but, until now, there has been no genetic proof that ABP1 and phytochrome regulation of elongation share a common mechanism for organ elongation. In far red (FR)-enriched light, hypocotyl lengths were larger in the abp1-5 and...

Early assessment of defects and damage in jet engines

Rafael R. Adamczuk & Jörg R. Seume
The jet engine maintenance process is complex, expensive and time-consuming. It often requires engine disassembly or boroscopic examinations. In order to accelerate the process and reduce the down time of an engine we intend to develop a method to locate and characterize defects and damage at an early state, without having to disassemble the engine. The assumption is that various defects in the hot gas path of an engine have a noticeable impact on the...

High permeability flexible bulk material for magnetic micro head applications

Alexander Belski, Piriya Taptimthong, Marc Christopher Wurz & Lutz Rissing
A magnetic field is generated by feeding electric current to micro coils. The higher the current, the higher the magnetic field is. A main disadvantage of coils in micro systems is the limited thermal resistance and as a result of a restriction concerning the maximum current densities. This work shows the modelling, design, numerical calculation and the initial test of a flexible write head, which not only allows the data storage on the surface but...

Abrasion monitoring and automatic chatter detection in cylindrical plunge grinding

M. Ahrens, R. Fischer, M. Dagen, Berend Denkena & Tobias Ortmaier
Using conventional grinding wheels, wheel-sided chatter vibration is one of the limiting factors in terms of productivity and surface finish. Initial vibration related to the dynamic behavior of the machine tool copy on the grinding wheel and its amplitude amplifies by abrasion. To ensure high workpiece quality many expensive truing cycles are needed. In this context, we suggest a new set-up for the automatic chatter detection and elimination for external cylindrical grinding machines, reducing not...

Monitoring concepts for coastal areas using lidar data

Alena Schmidt, Franz Rottensteiner & Uwe Sörgel
Coastal areas are characterized by high spatial and temporal variability. In order to detect undesired changes at early stages, enabling rapid countermeasures to mitigate or minimize potential harm or hazard, a recurrent monitoring becomes necessary. In this paper, we focus on two monitoring task: the analysis of morphological changes and the classification and mapping of habitats. Our concepts are solely based on airborne lidar data which provide substantial information in coastal areas. For the first...

Monitoring and change detection of wadden sea areas using lidar data

Alena Schmidt & Uwe Sörgel
In coastal areas morphological changes of various kinds are caused by tidal flows, storms, climate change, and human activities. For these reasons a recurrent monitoring becomes necessary in order to detect undesired changes at early stages enabling rapid countermeasures to mitigate or minimize potential harm or hazard. The morphology of the terrain can be represented by highly precise digital terrain models (DTM). Airborne lidar (light detection and ranging) has become a standard method for DTM...

Using lattice topology information to investigate persistent scatterers at facades in urban areas

Lukas Schack & Uwe Sörgel
Modern spaceborne SAR sensors like TerraS AR-X offer ground resolution of up to one meter in range and azimuth direction. Buildings, roads, bridges, and other man-made structures appear in such data often as regular patterns of strong and temporally stable points (Persistent Scatterer, PS). As one step in the process of unveiling what object structure actually causes the PS (i.e., physical nature) we compare those regular structures in SAR data to their correspondences in optical...

Opportunities of airborne laser bathymetry for the monitoring of the sea bed on the Baltic Sea coast

Joachim Niemeyer & Uwe Sörgel
Traditional ship-based bathymetric surveys based on echo sounding are expensive and time consuming. This paper presents a project with the aim of identifying the opportunities of airborne laser bathymetry for the monitoring of the sea bed at the German Baltic Sea coast. Such devices operate with laser signal in the green part of the visible spectrum which is capable to penetrate the water. The depth is determined from the two-way runtime between the water surface...

Multi-source hierarchical conditional random field model for feature fusion of remote sensing images and LiDAR data

Z. Zhang, M.Y. Yang & M. Zhoua
Feature fusion of remote sensing images and LiDAR points cloud data, which have strong complementarity, can effectively play the advantages of multi-class features to provide more reliable information support for the remote sensing applications, such as object classification and recognition. In this paper, we introduce a novel multi-source hierarchical conditional random field (MSHCRF) model to fuse features extracted from remote sensing images and LiDAR data for image classification. Firstly, typical features are selected to obtain...

Advanced representation of tubular joints in jacket models for offshore wind turbine simulation

Jan Dubois, Michael Muskulus & Peter Schaumann
Jacket substructures for offshore wind turbines show strong potentials in water depths from 25 up to 70m. A review of state-of-practice and enhanced state-of-the-art modeling of offshore wind turbine jackets is conducted regarding detailed joint properties. The state-of-the-art approach takes advantage of an accurate description of the local joint behavior by use of superelements, enabling more accurate load simulations. Studies conducted in the past highlighted both strong benefits as well as shortcomings of this approach,...

Visions and open challenges for a knowledge-based culturomics

Nina Tahmasebi, Lars Borin, Gabriele Capannini, Devdatt Dubhashi, Peter Exner, Markus Forsberg, Gerhard Gossen, Fredrik D. Johansson, Mikael Kågebäck, Olof Mogren, Pierre Nugues, Thomas Risse & Richard Johansson
The concept of culturomics was born out of the availability of massive amounts of textual data and the interest to make sense of cultural and language phenomena over time. Thus far however, culturomics has only made use of, and shown the great potential of, statistical methods. In this paper, we present a vision for a knowledge-based culturomics that complements traditional culturomics. We discuss the possibilities and challenges of combining knowledge-based methods with statistical methods and...

Sportunterricht in Sprachlernklassen - Der Stellenwert von Bewegung für geflüchtete Kinder und ihren Spracherwerb

Julius Bo Rackemann
Sprachförderung für Flüchtlinge im Sportunterricht anzubahnen, ist ein notwendiger und lohnender Bestandteil von adressatengerechtem Sportunterricht. Über eine Einordnung der Lebenssituation geflüchteter Kinder in Deutschland erfolgt eine Herleitung der Legitimationsebenen von Sport und Bewegung. Neben diesem Aspekt ist vor allem der Spracherwerb (Deutsch als Zweitsprache) ein bedeutungsvoller Faktor zur Steigerung des Wohlbefindens und der Handlungsfähigkeit in der Aufnahmegesellschaft. Die Verbindung beider Ebenen ist erklärtes Ziel eines sich anpassenden und weiterentwicklenden Sportunterrichts für diese Zielgruppe. Im und...

Solar energy conversion by nanostructured TiO

Jia Hong Pan, Detlef W. Bahnemann, Qing Wang, Chuanyi Wang & Xiwang Zhang
Research in solar energy conversion and the associated photoactive materials has attracted continuous interest. Due to its proper electronic band structure, high quantum efficiency, and photonic and chemical innerness, TiO2 has been demonstrated as a versatile oxide semiconductor capable of efficiently utilizing sunlight to produce electrical and chemical energy. Its outstanding physicochemical performances have led to an array of advanced photocatalytic and photoelectrochemical applications including environmental photocatalysis, dye/semiconductor-sensitized solar cell, and solar fuel productions.

New rural dynamics and challenges in the Global South

T. Rauch, M. Schmidt & D. Segebart
Dealing with rural areas in the Global South must be a central concern of geographical development research in the 21st century. Major challenges for the global community, such as the unsolved energy and food questions, the migration of people and increasing natural hazards as a result of climate change processes, are fundamentally linked with rural areas. Most natural resources - biotic and abiotic - are located in the rural environment, which provides land for the...

Dissemination bias in systematic reviews of animal research: A systematic review

Katharina F. Müller, Matthias Briel, Daniel Strech, Jörg J. Meerpohl, Britta Lang, Edith Motschall, Viktoria Gloy, Francois Lamontagne & Dirk Bassler
Background: Systematic reviews of preclinical studies, in vivo animal experiments in particular, can influence clinical research and thus even clinical care. Dissemination bias, selective dissemination of positive or significant results, is one of the major threats to validity in systematic reviews also in the realm of animal studies. We conducted a systematic review to determine the number of published systematic reviews of animal studies until present, to investigate their methodological features especially with respect to...

Biologic TNF inhibiting agents for treatment of rheumatoid arthritis: persistence and dosing patterns in Germany

Sarah Neubauer, Mary Cifaldi, Thomas Mittendorf, Arijit Ganguli, Malte Wolff & Jan Zeidler
Objective: To obtain detailed real-world data on persistence and dosing patterns in the utilisation of the TNF inhibitors adalimumab, etanercept, and infliximab in rheumatoid arthritis (RA) patients treated in Germany. Methods: In this retrospective observational study claims data of a major German health insurance fund between 2005 and 2008 were analysed. Patients receiving at least one prescription of adalimumab, etanercept or infliximab were identified and categorised as "TNF inhibitor naive" or "TNF inhibitor continuing". For...

Registration Year

  • 2016

Resource Types

  • Collection

Data Centers

  • Leibniz Universität Hannover