0000000000139050
AUTHOR
Christian Schneider
New HAXPES Applications at PETRA III
The application of photoelectron spectroscopy using hard X-rays (HAXPES) is becoming increasingly popular as a powerful spectroscopic tool in materials science. The success of HAXPES lies in the fa...
Regulatory evaluation of Glybera in Europe — two committees, one mission
Representing the first gene therapy to be approved in the Western world, alipogene tiparvovec (Glybera; Uniqure) has recently been said to have had a “substantial impact from a regulatory perspective” (Nature Rev. Drug Discov. 11, 664; 2012) 1 . The therapy was granted marketing authorization in the European Union for the treatment of lipoprotein lipase deficiency, which results in a clinically heterogeneous condition with a risk of potentially life-threatening pancreatitis 2 , at the end of 2012. The decision followed a positive opinion by the European Medicines Agency (EMA)’s Committee for Medicinal Products for Human Use (CHMP) 3
Self-Trapping of Magnetic Oscillation Modes in Landau Flux-Closure Structures
We investigated the magnetodynamics in rectangular Permalloy platelets by means of time-resolved x-ray photoemission microscopy. 10 nm thick platelets of size 16 x 32 microm were excited by an oscillatory field along the short side of the sample with a fundamental frequency of 500 MHz and considerable contributions of higher harmonics. Under the influence of the oscillatory field, the Néel wall in the initial classical Landau pattern shifts away from the center, corresponding to an induced magnetic moment perpendicular to the exciting field. This phenomenon is explained by a self-trapping effect of the dominating spin-wave mode when the system is excited just below the resonance frequency. …
Spatially resolved observation of dynamics in electrical and magnetic field distributions by means of a delayline detector and PEEM
Abstract Photoemission electron microscopy (PEEM) was exploited to observe the dynamics in local field distributions on microstrip-line devices with a best time resolution of 133 ps. A delayline detector system served as imaging unit capable of a time resolving data acquisition and processing. The setup can be operated at the resolution limit of the PEEM of about 20 nm while a continuously illuminating UV-lamp excites the photoelectrons in threshold photoemission. A pulsed photon source is not needed to obtain time resolved images, the time reference of the data acquisition was taken by a periodic signal (clock, here typ. 100 MHz) in phase with the pulse pattern applied to the microstrip-li…
Intrahematomal Ultrasound Enhances RtPA-Fibrinolysis in a Porcine Model of Intracerebral Hemorrhage
Catheter-based ultrasound-thrombolysis has been successfully used in a small clinical trial in order to enhance recombinant tissue plasminogen activator (rtPA)-fibrinolysis, for the treatment of spontaneous intracerebral hemorrhages (ICHs). The aim of this study was to investigate the ultra-early effects of ultrasound on hematoma and the surrounding brain tissue in a porcine ICH-model. To achieve this, 21 pigs with a right frontal ICH were randomly assigned to four groups: (1) drainage (n = 3), (2) drainage + rtPA (n = 6), (3) drainage + ultrasound (n = 6), and (4) drainage + ultrasound + rtPA (n = 6). The hematoma volume assessment was performed using cranial MRI before and after the treat…
Manufacturing, characterization and control of cell-based medicinal products: challenging paradigms toward commercial use
During the past decade, a large number of cell-based medicinal products have been tested in clinical trials for the treatment of various diseases and tissue defects. However, licensed products and those approaching marketing authorization are still few. One major area of challenge is the manufacturing and quality development of these complex products, for which significant manipulation of cells might be required. While the paradigms of quality, safety and efficacy must apply also to these innovative products, their demonstration may be demanding. Demonstration of comparability between production processes and batches may be difficult for cell-based medicinal products. Thus, the development …
Time-resolved X-ray photoemission electron microscopy: imaging magnetodynamics on the 100 ps scale and below
Abstract We present recent results of time-resolved X-ray photoemission electron microscopy (TR-XPEEM) investigations on magnetic systems. Our studies of microstructured permalloy particles employ a magnetic pump XPEEM probe approach. The stroboscopic experiments feature a time resolution of Δ τ ≤ 130 ps and yield magnetic domain images with a surprising richness of details. We observe a strong influence of incoherent magnetization rotation processes, which lead to complicated transient domain structures with a blocked relaxation behavior.
Orbital mapping of carbon thin films by XANES-spectromicroscopy
Abstract A laterally resolved micro-XANES study (X-ray absorption near edge structure) of amorphous carbon, hydrogen terminated CVD-diamond (100) and highly oriented pyrolytic graphite (HOPG) is presented. The results were obtained by means of a photoemission electron microscope. Using this technique the well-known spectral features of carbon in its different chemical states (sp 2 , sp 3 ) could be recorded. The sp 2 /sp 3 content of the films was extracted from the spectra. Images, taken at X-ray energies corresponding to maxima (π*, C–H*) of the unoccupied density of states in these spectra, map the lateral distribution of the different orbitals at the sample surface. This study revealed …
Time- and energy resolved photoemission electron microscopy-imaging of photoelectron time-of-flight analysis by means of pulsed excitations
Abstract The present work enlightens the developments in time- and energy resolved photoemission electron microscopy over the past few years. We describe basic principles of the technique and demonstrate different applications. An energy- and time-filtering photoemission electron microscopy (PEEM) for real-time spectroscopic imaging can be realized either by a retarding field or hemispherical energy analyzer or by using time-of-flight optics with a delay line detector. The latter method has the advantage of no data loss at all as all randomly incoming particles are measured not only by position but also by time. This is of particular interest for pump–probe experiments in the femtosecond an…