Time filter

Source Type

Wysokowski M.,Poznan University of Technology | Motylenko M.,TU Bergakademie Freiberg | Beyer J.,TU Bergakademie Freiberg | Makarova A.,TU Dresden | And 20 more authors.
Nano Research | Year: 2015

This work presents an extreme biomimetics route for the creation of nanostructured biocomposites utilizing a chitinous template of poriferan origin. The specific thermal stability of the nanostructured chitinous template allowed for the formation under hydrothermal conditions of a novel germanium oxide-chitin composite with a defined nanoscale structure. Using a variety of analytical techniques (FTIR, Raman, energy dispersive X-ray (EDX), near-edge X-ray absorption fine structure (NEXAFS), and photoluminescence (PL) spectroscopy, EDS-mapping, selected area for the electron diffraction pattern (SAEDP), and transmission electron microscopy (TEM)), we showed that this bioorganic scaffold induces the growth of GeO2 nanocrystals with a narrow (150–300 nm) size distribution and predominantly hexagonal phase, demonstrating the chitin template’s control over the crystal morphology. The formed GeO2–chitin composite showed several specific physical properties, such as a striking enhancement in photoluminescence exceeding values previously reported in GeO2-based biomaterials. These data demonstrate the potential of extreme biomimetics for developing new-generation nanostructured materials. [Figure not available: see fulltext.] © 2015, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

Fenalti G.,Scripps Research Institute | Fenalti G.,Celgene | Zatsepin N.A.,Arizona State University | Betti C.,Vrije Universiteit Brussel | And 45 more authors.
Nature Structural and Molecular Biology | Year: 2015

Bifunctional μ- and δ-opioid receptor (OR) ligands are potential therapeutic alternatives, with diminished side effects, to alkaloid opiate analgesics. We solved the structure of human δ-OR bound to the bifunctional δ-OR antagonist and μ-OR agonist tetrapeptide H-Dmt-Tic-Phe-Phe-NH 2 (DIPP-NH 2) by serial femtosecond crystallography, revealing a cis-peptide bond between H-Dmt and Tic. The observed receptor-peptide interactions are critical for understanding of the pharmacological profiles of opioid peptides and for development of improved analgesics. © 2015 Nature America, Inc.

Wysokowski M.,Poznan University of Technology | Motylenko M.,TU Bergakademie Freiberg | Walter J.,TU Bergakademie Freiberg | Lota G.,Poznan University of Technology | And 19 more authors.
RSC Advances | Year: 2014

Chitin of poriferan origin is a unique and thermostable biological material. It also represents an example of a renewable materials source due to the high regeneration ability of Aplysina sponges under marine ranching conditions. Chitinous scaffolds isolated from the skeleton of the marine sponge Aplysina aerophoba were used as a template for the in vitro formation of Fe2O3 under conditions (pH ∼ 1.5, 90°C) which are extreme for biological materials. Novel chitin-Fe2O3 three dimensional composites, which have been prepared for the first time using hydrothermal synthesis, were thoroughly characterized using numerous analytical methods including Raman spectroscopy, XPS, XRD, electron diffraction and HR-TEM. We demonstrate the growth of uniform Fe2O3 nanocrystals into the nanostructured chitin substrate and propose a possible mechanism of chitin-hematite interactions. Moreover, we show that composites made of sponge chitin-Fe2O3 hybrid materials with active carbon can be successfully used as electrode materials for electrochemical capacitors. © The Royal Society of Chemistry 2014.

Wysokowski M.,Poznan University of Technology | Materna K.,Poznan University of Technology | Walter J.,TU Bergakademie Freiberg | Petrenko I.,TU Bergakademie Freiberg | And 12 more authors.
International Journal of Biological Macromolecules | Year: 2015

Chitinous scaffolds isolated from the skeleton of marine sponge Aplysina cauliformis were used as a template for the deposition of polyhedral oligomeric silsesquioxanes (POSS). These chitin-POSS based composites with hydrophobic properties were prepared for the first time using solvothermal synthesis (pH 3, temp 80. °C), and were thoroughly characterized. The resulting material was studied using scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and thermogravimetry. A mechanism for the chitin-POSS interaction after exposure to these solvothermal conditions is proposed and discussed. © 2015 Elsevier B.V.

Steinberger R.,Johannes Kepler University | Walter J.,TU Bergakademie Freiberg | Greunz T.,Johannes Kepler University | Duchoslav J.,Johannes Kepler University | And 6 more authors.
Corrosion Science | Year: 2015

Monoatomic ion guns mounted on X-ray photoelectron spectrometers are frequently used for depth profiling to determine the depth distribution of various chemical compounds, or for surface cleaning. Sputtering with single ions may cause severe damage to some materials. Hence, in this study the influence of different sputter parameters on the degradation kinetics was examined. For comparison, the potential of Ar cluster sputtering was tested with the same materials, namely hydrozincite and FeO - two representatives of corrosion products that are susceptible to degradation. Chemical damage could only be minimized by cooling or cluster sputtering within a narrow cluster energy window. © 2015 Elsevier Ltd.

Iwawaki T.,Osaka University | Habara H.,Osaka University | Baton S.,University Pierre and Marie Curie | Morita K.,Osaka University | And 8 more authors.
Physics of Plasmas | Year: 2014

Significantly collimated fast electron beam with a divergence angle 10° (FWHM) is observed when an ultra-intense laser pulse (I = 1014 W/cm2, 300 fs) irradiates a uniform critical density plasma. The uniform plasma is created through the ionization of an ultra-low density (5mg/c.c.) plastic foam by X-ray burst from the interaction of intense laser (I = 1014 W/cm2, 600 ps) with a thin Cu foil. 2D Particle-In-Cell (PIC) simulation well reproduces the collimated electron beam with a strong magnetic field in the region of the laser pulse propagation. To understand the physical mechanism of the collimation, we calculate energetic electron motion in the magnetic field obtained from the 2D PIC simulation. As the results, the strong magnetic field (300 MG) collimates electrons with energy over a few MeV. This collimation mechanism may attract attention in many applications such as electron acceleration, electron microscope and fast ignition of laser fusion. © 2014 AIP Publishing LLC.

Iwawaki T.,Osaka University | Habara H.,Osaka University | Baton S.,University Pierre and Marie Curie | Morita K.,Osaka University | And 8 more authors.
Plasma and Fusion Research | Year: 2015

Significantly collimated fast electron beam with a divergence angle 10° (FWHM) is generated through the interaction of ultra-intense laser light with a uniform critical density plasma in experiments and 2D PIC simulations. In the experiment, the uniform critical density plasma is created by ionizing an ultra-low density foam target. The spacial distribution of the fast electron is observed by Imaging Plate. 2D PIC simulation and post process analysis reveal magnetic collimation of energetic electrons along the plasma channel. © 2015 The Japan Society of Plasma Science and Nuclear Fusion Research.

Loading European X Ray Free Electronic Laser Facility XFEL GmbH collaborators
Loading European X Ray Free Electronic Laser Facility XFEL GmbH collaborators