231 results match your criteria: "Braunschweig University of Technology[Affiliation]"

Using DNA origami nanorulers as traceable distance measurement standards and nanoscopic benchmark structures.

Sci Rep

January 2018

Institute for Physical & Theoretical Chemistry, and Braunschweig, Integrated Centre of Systems Biology (BRICS) and Laboratory for Emerging Nanometrology (LENA), Braunschweig University of Technology, Rebenring 56, 38106, Braunschweig, Germany.

In recent years, DNA origami nanorulers for superresolution (SR) fluorescence microscopy have been developed from fundamental proof-of-principle experiments to commercially available test structures. The self-assembled nanostructures allow placing a defined number of fluorescent dye molecules in defined geometries in the nanometer range. Besides the unprecedented control over matter on the nanoscale, robust DNA origami nanorulers are reproducibly obtained in high yields.

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Strong Plasmonic Enhancement of a Single Peridinin-Chlorophyll a-Protein Complex on DNA Origami-Based Optical Antennas.

ACS Nano

February 2018

Institute for Physical & Theoretical Chemistry, and Braunschweig Integrated Centre of Systems Biology (BRICS), and Laboratory for Emerging Nanometrology (LENA), Braunschweig University of Technology, 38106 Braunschweig, Germany.

In this contribution, we fabricate hybrid constructs based on a natural light-harvesting complex, peridinin-chlorophyll a-protein, coupled to dimer optical antennas self-assembled with the help of the DNA origami technique. This approach enables controlled positioning of individual complexes at the hotspot of the optical antennas based on large, colloidal gold and silver nanoparticles. Our approach allows us to selectively excite the different pigments present in the harvesting complex, reaching a fluorescence enhancement of 500-fold.

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Electrospun poly(ε-caprolactone) (PCL) fiber mats are modified using a chitosan grafted with PCL (CS-g-PCL), to improve the biological performance and to enable further modifications. The graft copolymer is immobilized by the crystallization of the PCL grafts on the PCL fiber surface as binding mechanism. In this way, the surface of the fibers is covered with chitosan bearing cationic amino groups, which allow adsorption of oppositely charged nanoparticulate drug-delivery systems.

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Cell migration frequently involves the protrusion of lamellipodial actin networks, the structure and regulation of which have been studied for decades. New work highlights how the geometry of these networks endows cells with the ability to adapt to environmental conditions and load.

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DNA nanotechnology has developed into a state where the design and assembly of complex nanoscale structures has become fast, reliable, cost-effective, and accessible to non-experts. Nanometer-precise positioning of organic (dyes, biomolecules, etc.) and inorganic (metal nanoparticles, colloidal quantum dots, etc.

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Optical Nanoantenna for Single Molecule-Based Detection of Zika Virus Nucleic Acids without Molecular Multiplication.

Anal Chem

December 2017

Institute for Physical and Theoretical Chemistry, and Braunschweig Integrated Centre of Systems Biology (BRICS), and Laboratory for Emerging Nanometrology (LENA), Braunschweig University of Technology, Rebenring 56, 38106 Braunschweig, Germany.

Because of the limited signal-to-background ratio, molecular diagnostics requires molecular amplification of the target molecules or molecular signal amplification after target recognition. For direct molecular detection, we demonstrate a purely physical fluorescence enhancement process which can elevate the fluorescence signal of single fluorescent dyes by several orders of magnitude. To this end, DNA origami-based optical antennas with a height of around 125 nm are used, which utilize metallic nanoparticles to create a hotspot where fluorescence signals are enhanced by plasmonic effects.

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One of the greatest challenges of effective conservation measures is the correct identification of sites where rare and elusive organisms reside. The recently rediscovered Hula painted frog (Latonia nigriventer) has not been seen for many decades and was therefore categorized extinct. Since its rediscovery in 2011, individuals from the critically endangered species have been found, with great effort, only in four restricted sites.

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Objective: In cochlea implantation, assessment of the electrically evoked stapedius reflex threshold (eSRT) provides information for postoperative adjustment of the speech processor. This is used to prevent undesired overstimulation. To this day, the reflex is visually identified by the surgeon.

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The stomach serves as food reservoir, mixing organ and absorption area for certain substances, while continually varying its position and size. Large dimensional changes during ingestion and gastric emptying of the stomach are associated with large changes in smooth muscle length. These length changes might induce history-effects, namely force depression (FD) following active muscle shortening and force enhancement (FE) following active muscle stretch.

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Highly Specific and Wide Range NO Sensor with Color Readout.

ACS Sens

November 2017

MIND-Departament of Electronic and Biomedial Engineering, ‡Institute of Nanoscience and Nanotechnology (IN2UB), and §DIOPMA, Departament de Ciència de Materials i Química Física, Universitat de Barcelona, c/Martí i Franquès 1, E-08028 Barcelona, Spain.

We present a simple and inexpensive method to implement a Griess-Saltzman-type reaction that combines the advantages of the liquid phase method (high specificity and fast response time) with the benefits of a solid implementation (easy to handle). We demonstrate that the measurements can be carried out using conventional RGB sensors; circumventing all the limitations around the measurement of the samples with spectrometers. We also present a method to optimize the measurement protocol and target a specific range of NO concentrations.

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Synergistic Combination of Unquenching and Plasmonic Fluorescence Enhancement in Fluorogenic Nucleic Acid Hybridization Probes.

Nano Lett

October 2017

Institute for Physical and Theoretical Chemistry, and Braunschweig Integrated Centre of Systems Biology (BRICS), and Laboratory for Emerging Nanometrology (LENA), Braunschweig University of Technology, Rebenring 56, 38106 Braunschweig, Germany.

Fluorogenic nucleic acid hybridization probes are widely used for detecting and quantifying nucleic acids. The achieved sensitivity strongly depends on the contrast between a quenched closed form and an unquenched opened form with liberated fluorescence. So far, this contrast was improved by improving the quenching efficiency of the closed form.

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Objectives: Intramedullary nailing is the treatment of choice for femoral shaft fractures. However, there are several problems associated with the technique, e.g.

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Members of the class Blastocatellia are frequently found in soils with a neutral and (slightly) basic pH where they constitute an important fraction of the microbial community. A novel representative of the class Blastocatellia was isolated from a Ghanaian soil and was characterized in detail. Cells of strain A24_SHP_-5_238 were non-motile rods that divided by binary fission and formed orange to salmon-coloured colonies on agar plates.

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Purpose: We designed an experiment to determine the comparative effectiveness of computer algorithms for performing automated long bone fracture reduction.

Methods: Automated reduction of 10 3D fracture models was performed using two computer algorithms, random sample matching (RANSAM) and Z-buffering (Z-Buffer), and one of five options of post-processing: none; iterative closest point algorithm (ICP); ICP-X1; ICP-X2; and ICP-X3. We measured the final alignment between the two fragments for each algorithm and post-processing option.

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Phylotranscriptomic consolidation of the jawed vertebrate timetree.

Nat Ecol Evol

September 2017

Centre for Biodiversity Theory and Modelling, UMR CNRS 5321, Station of Theoretical and Experimental Ecology, Moulis, 09200, France.

Phylogenomics is extremely powerful but introduces new challenges as no agreement exists on "standards" for data selection, curation and tree inference. We use jawed vertebrates (Gnathostomata) as model to address these issues. Despite considerable efforts in resolving their evolutionary history and macroevolution, few studies have included a full phylogenetic diversity of gnathostomes and some relationships remain controversial.

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We evaluate the inter- and intraobserver variability of a telemanipulated femur fracture reduction system using a joystick device. Five examiners performed virtual reduction of 3D femur fracture models on two separate occasions. We assessed the inter- and intraobserver variability for the final alignment and reduction.

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Embryonic zebrafish primary cell culture for transfection and live cellular and subcellular imaging.

Dev Biol

October 2017

Division of Cellular and Molecular Neurobiology, Zoological Institute, Braunschweig University of Technology, 38106 Braunschweig, Germany. Electronic address:

Although having great potential for live cell imaging to address numerous cell biological questions with high spatial and temporal resolution, primary cell cultures of zebrafish embryos are not widely used. We present an easy-to-use protocol for preparing primary cell cultures of 2 dpf zebrafish embryos allowing for live cell imaging of fully differentiated cells such as neurons and myocytes. We demonstrate that different cell types can be identified by morphology and expression of transgenic cell type-specific fluorescent reporters and that fluorescent cells can be sorted by flow cytometry to prepare an enriched culture.

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We aimed to test whether a robotic technique would offer more accurate access to the proximal femoral medullary cavity for insertion of an intramedullary nail compared to the conventional manual technique. The medullary cavity of ten femur specimens was accessed in a conventional fashion using fluoroscopic control. In ten additional femur specimens, ISO-C 3D scans were obtained and a computer program calculated the ideal location of the cavity opening based on the trajectory of the medullary canal.

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A DNA Walker as a Fluorescence Signal Amplifier.

Nano Lett

September 2017

Institute for Physical & Theoretical Chemistry, and Braunschweig Integrated Centre of Systems Biology (BRICS), and Laboratory for Emerging Nanometrology (LENA), Braunschweig University of Technology, 38106 Braunschweig, Germany.

Sensing nucleic acids typically involves the recognition of a specific sequence and reporting by, for example, a fluorogenic reaction yielding one activated dye molecule per detected nucleic acid. Here, we show that after binding to a DNA origami track a bound DNA target (a "DNA walker") can release the fluorescence of many molecules by acting as the catalyst of an enzymatic nicking reaction. As the walking kinetics sensitively depends on the walker sequence, the resulting brightness distribution of DNA origamis is a sequence fingerprint with single-nucleotide sensitivity.

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The rise of high-throughput sequencing techniques provides the unprecedented opportunity to analyse controversial phylogenetic relationships in great depth, but also introduces a risk of being misinterpreted by high node support values influenced by unevenly distributed missing data or unrealistic model assumptions. Here, we use three largely independent phylogenomic data sets to reconstruct the controversial phylogeny of true salamanders of the genus Salamandra, a group of amphibians providing an intriguing model to study the evolution of aposematism and viviparity. For all six species of the genus Salamandra, and two outgroup species from its sister genus Lyciasalamandra, we used RNA sequencing (RNAseq) and restriction site associated DNA sequencing (RADseq) to obtain data for: (1) 3070 nuclear protein-coding genes from RNAseq; (2) 7440 loci obtained by RADseq; and (3) full mitochondrial genomes.

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Interlocked intramedullary nailing is the treatment of choice for femoral shaft fractures. However, distal locking is a technically challenging part of the procedure that can result in distal femoral malrotation and high radiation exposure. We have tested a robotic procedure for robotic distal locking based on the computation of a drilling trajectory on two calibrated fluoroscopic images.

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Plasmonics Enhanced Smartphone Fluorescence Microscopy.

Sci Rep

May 2017

Electrical Engineering Department, University of California, Los Angeles, Los Angeles, CA, 90095, USA.

Smartphone fluorescence microscopy has various applications in point-of-care (POC) testing and diagnostics, ranging from e.g., quantification of immunoassays, detection of microorganisms, to sensing of viruses.

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Background: Oscillating saws generate high levels of heat (up to 150°C), which can lead to tissue necrosis, delayed healing and infection. Abrasive waterjet-cutting techniques have been described as a new tool to perform bone cuts, with less heat generation.

Methods: Four lower-limbs of four human alcohol conserved cadavers were tested.

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Broadband Fluorescence Enhancement with Self-Assembled Silver Nanoparticle Optical Antennas.

ACS Nano

May 2017

Institute for Physical and Theoretical Chemistry, Braunschweig Integrated Centre of Systems Biology (BRICS), and Laboratory for Emerging Nanometrology (LENA), Braunschweig University of Technology, 38106 Braunschweig, Germany.

Plasmonic structures are known to affect the fluorescence properties of dyes placed in close proximity. This effect has been exploited in combination with single-molecule techniques for several applications in the field of biosensing. Among these plasmonic structures, top-down zero-mode waveguides stand out due to their broadband capabilities.

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Animal-associated bacterial communities play essential roles for their host's ecology, physiology and health. Temporal dynamics of these communities are poorly understood, but might be of high relevance for amphibians with a well-expressed biphasic biology of adults where the structure of their skin changes drastically between the aquatic and terrestrial phases. Here, we investigated the temporal dynamics of cutaneous bacterial communities of Lissotriton boscai and Triturus marmoratus by monthly sampling populations from a pond and surrounding terrestrial habitats near A Coruña, Spain.

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