255 research outputs found
Nordic Post-Graduate Sustainable Design and Engineering Research from a Supervisor Perspective
The multi- and interdisciplinary field of sustainable product innovation is rapidly expanding as an arena for scientific research. Universities in Nordic countries can be considered as an exponent of this type of research, with active research groups in, among others, Göteborg, Helsinki, Lund, Lyngby, Linköping and Trondheim. In the context of a Nordforsk funded project, seven second generation PhD supervisors from these universities, who have been active in this field for many years, discuss funding, publication, research traditions, education and supervision practices related to PhD research in this field. A number of recommendations to improve current practices are made, including the mapping currently existing differences in different academic institutions, studying the cross-over learning effects between academica and non-academic partners, and the development of âquality indicatorsâ of research in the SPI domain
LUX -- A Laser-Plasma Driven Undulator Beamline
The LUX beamline is a novel type of laser-plasma accelerator. Building on the
joint expertise of the University of Hamburg and DESY the beamline was
carefully designed to combine state-of-the-art expertise in laser-plasma
acceleration with the latest advances in accelerator technology and beam
diagnostics. LUX introduces a paradigm change moving from single-shot
demonstration experiments towards available, stable and controllable
accelerator operation. Here, we discuss the general design concepts of LUX and
present first critical milestones that have recently been achieved, including
the generation of electron beams at the repetition rate of up to 5 Hz with
energies above 600 MeV and the generation of spontaneous undulator radiation at
a wavelength well below 9 nm.Comment: submitte
Chirp mitigation of plasma-accelerated beams using a modulated plasma density
Plasma-based accelerators offer the possibility to drive future compact light
sources and high-energy physics applications. Achieving good beam quality,
especially a small beam energy spread, is still one of the major challenges.
For stable transport, the beam is located in the focusing region of the
wakefield which covers only the slope of the accelerating field. This, however,
imprints a longitudinal energy correlation (chirp) along the bunch. Here, we
propose an alternating focusing scheme in the plasma to mitigate the
development of this chirp and thus maintain a small energy spread
Carrier frequencies of eleven mutations in eight genes associated with primary ciliary dyskinesia in the ashkenazi jewish population
Primary ciliary dyskinesia (PCD) is a genetically heterogeneous, autosomal recessive disorder that results from functional and ultrastructural abnormalities of motile cilia. Patients with PCD have diverse clinical phenotypes that include chronic upper and lower respiratory tract infections, situs inversus, heterotaxy with or without congenital heart disease, and male infertility, among others. In this report, the carrier frequencies for eleven mutations in eight PCD-associated genes (DNAI1, DNAI2, DNAH5, DNAH11, CCDC114, CCDC40, CCDC65, and C21orf59) that had been found in individuals of Ashkenazi Jewish descent were investigated in order to advise on including them in existing clinical mutation panels for this population. Results showed relatively high carrier frequencies for the DNAH5 c.7502G>C mutation (0.58%), the DNAI2 c.1304G>A mutation (0.50%), and the C21orf59 c.735C>G mutation (0.48%), as well as lower frequencies for mutations in DNAI1, CCDC65, CCDC114, and DNAH11 (0.10â 0.29%). These results suggest that several of these genes should be considered for inclusion in carrier screening panels in the Ashkenazi Jewish population
Developing a 50 MeV LPA-based Injector at ATHENA for a Compact Storage Ring
The laser-driven generation of relativistic electron beams in plasma and
their acceleration to high energies with GV/m-gradients has been successfully
demonstrated. Now, it is time to focus on the application of laser-plasma
accelerated (LPA) beams. The "Accelerator Technology HElmholtz iNfrAstructure"
(ATHENA) of the Helmholtz Association fosters innovative particle accelerators
and high-power laser technology. As part of the ATHENAe pillar several
different applications driven by LPAs are to be developed, such as a compact
FEL, medical imaging and the first realization of LPA-beam injection into a
storage ring. The latter endeavour is conducted in close collaboration between
Deutsches Elektronen-Synchrotron (DESY), Karlsruhe Institute of Technology
(KIT) and Helmholtz Institute Jena (HIJ). In the cSTART project at KIT, a
compact storage ring optimized for short bunches and suitable to accept
LPA-based electron bunches is in preparation. In this conference contribution
we will introduce the 50 MeV LPA-based injector and give an overview about the
project goals. The key parameters of the plasma injector will be presented.
Finally, the current status of the project will be summarized
Status Report of the 50 MeV LPA-Based Injector at ATHENA for a Compact Storage Ring
Laser-based plasma accelerators (LPA) have successfully demonstrated their capability to generate high-energy electron beams with intrinsically short bunch lengths and high peak currents at a setup with a small footprint. These properties make them attractive drivers for a broad range of different applications including injectors for rf-driven, ring-based light sources. In close collaboration the Deutsches Elektronen-Synchrotron (DESY), the Karlsruhe Institute of Technology (KIT) and the Helmholtz Institute Jena aim to develop a 50 MeV plasma injector and demonstrate the injection into a compact storage ring. This storage ring will be built within the project cSTART at KIT. As part of the ATHENA (Accelerator Technology HElmholtz iNfrAstructure) project, DESY will design, setup and operate a 50 MeV plasma injector prototype for this endeavor. This contribution gives a status update of the 50 MeV LPA-based injector and presents a first layout of the prototype design at DESY in Hamburg
Topological Photonics
Topology is revolutionizing photonics, bringing with it new theoretical
discoveries and a wealth of potential applications. This field was inspired by
the discovery of topological insulators, in which interfacial electrons
transport without dissipation even in the presence of impurities. Similarly,
new optical mirrors of different wave-vector space topologies have been
constructed to support new states of light propagating at their interfaces.
These novel waveguides allow light to flow around large imperfections without
back-reflection. The present review explains the underlying principles and
highlights the major findings in photonic crystals, coupled resonators,
metamaterials and quasicrystals.Comment: progress and review of an emerging field, 12 pages, 6 figures and 1
tabl
Clocking Auger electrons
Intense X-ray free-electron lasers (XFELs) can rapidly excite matter, leaving it in inherently unstable states that decay on femtosecond timescales. The relaxation occurs primarily via Auger emission, so excited-state observations are constrained by Auger decay. In situ measurement of this process is therefore crucial, yet it has thus far remained elusive in XFELs owing to inherent timing and phase jitter, which can be orders of magnitude larger than the timescale of Auger decay. Here we develop an approach termed âself-referenced attosecond streakingâ that provides subfemtosecond resolution in spite of jitter, enabling time-domain measurement of the delay between photoemission and Auger emission in atomic neon excited by intense, femtosecond pulses from an XFEL. Using a fully quantum-mechanical description that treats the ionization, core-hole formation and Auger emission as a single process, the observed delay yields an Auger decay lifetime of 2.2_â0.3^+0.2 fs for the KLL decay channel
Clocking Auger Electrons
Intense X-ray free-electron lasers (XFELs) can rapidly excite matter, leaving
it in inherently unstable states that decay on femtosecond timescales. As the
relaxation occurs primarily via Auger emission, excited state observations are
constrained by Auger decay. In situ measurement of this process is therefore
crucial, yet it has thus far remained elusive at XFELs due to inherent timing
and phase jitter, which can be orders of magnitude larger than the timescale of
Auger decay. Here, we develop a new approach termed self-referenced attosecond
streaking, based upon simultaneous measurements of streaked photo- and Auger
electrons. Our technique enables sub-femtosecond resolution in spite of jitter.
We exploit this method to make the first XFEL time-domain measurement of the
Auger decay lifetime in atomic neon, and, by using a fully quantum-mechanical
description, retrieve a lifetime of fs for the KLL
decay channel. Importantly, our technique can be generalised to permit the
extension of attosecond time-resolved experiments to all current and future FEL
facilities.Comment: Main text: 20 pages, 3 figures. Supplementary information: 17 pages,
6 figure
Potential use of deodorised water extracts: polyphenol-rich extract of Thymus pannonicus All. as a chemopreventive agent
Deodorised water extracts of aromatic plants are obtained as by-products of essential oil isolation and usually discarded as waste. However, phytochemical composition of these extracts encourages their further utilization as food additives or functional food ingredients. In this study we investigated phytochemical composition, antioxidant and in vivo antiproliferative activity of deodorised water extract of Thymus pannonicus All. (DWE). HPLC analysis revealed rosmarinic acid (RA) (71.11 +/- 1.54 mg/g) as the most abundant constituent of the extract, followed by salvianolic acid H (14.83 +/- 0.79 mg/g, calculated as RA). DWE exhibited pronounced antioxidant activity in vitro, in FRAP and DPPH tests (FRAP value: 7.41 mmol Fe/g and SC50: 3.80 mu g/g, respectively). Using the model of Ehrlich carcinoma cells in mice that were treated with DWE prior, at the time, and after tumour cells implantation, the tumour growth suppression and redox status of malignant cells (i.e., activities of antioxidant enzymes, level of glutathione and intensity of lipid peroxidation) were followed. DWE applied as pretreatment caused disturbance of antioxidant equilibrium as well as apoptosis/necrosis of up to 90% EAC cells. Results obtained in the present study revealed chemopreventive potential and possibility of T. pannonicus DWE usage. High content of RA and other phenolic compounds explains, at least in part, the observed effects
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