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  • 1
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    Inertia gravity wave in the stratosphere and mesosphere observed by Doppler wind and temperature lidar (2015)
    Wiley
    Details
    Publication Date: 2015-12-12
    Description: We report on the first observation of persistent inertia gravity wave signatures in the horizontal wind and temperature by Doppler Rayleigh lidar in the middle atmosphere. The observations were performed at the ALOMAR research station in northern Norway (69N,16E) between January 21 and 23, 2012. The measurements cover the altitude range from 20 km to about 80 km during night and to about 70 km during daytime. We observe amplitudes of 5 to 25 m/s and 1 to 8 K in wind and temperature, respectively. The measured kinetic to potential energy density ratio is about 10, indicating that the majority of variability is due to waves with intrinsic frequencies close to the inertial frequency. The entire wave field is mainly characterized by the presence of multiple waves, however quasi monochromatic waves could be identified at limited times around 60 km altitude with a mean momentum flux in direction of propagation of 3.8 m 2 /s 2 .
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 2
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    Superconducting films fabricated by high-fluence Ga implantation in Si (2011)
    American Physical Society (APS)
    Details
    Publication Date: 2011-06-04
    Description: Author(s): J. Fiedler, V. Heera, R. Skrotzki, T. Herrmannsdörfer, M. Voelskow, A. Mücklich, S. Oswald, B. Schmidt, W. Skorupa, G. Gobsch, J. Wosnitza, and M. Helm Ga-rich layers in Si were fabricated by 80 keV Ga implantation through a 30 nm SiO 2 cover layer and subsequent rapid thermal annealing for 60 s in a temperature range between 500 °C and 1000 °C. Fluences of 2×10 16 cm -2 and 4×10 16 cm -2 , leading to Ga peak concentrations of 8 at. % and 16 at. %, are c... [Phys. Rev. B 83, 214504] Published Fri Jun 03, 2011
    Keywords: Superfluidity and superconductivity
    Print ISSN: 1098-0121
    Electronic ISSN: 1095-3795
    Topics: Physics
    Published by American Physical Society (APS)
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  • 3
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    Superconducting Ga-overdoped Ge layers capped with SiO_{2}: Structural and transport investigations (2012)
    American Physical Society (APS)
    Details
    Publication Date: 2012-04-28
    Description: Author(s): J. Fiedler, V. Heera, R. Skrotzki, T. Herrmannsdörfer, M. Voelskow, A. Mücklich, S. Facsko, H. Reuther, M. Perego, K.-H. Heinig, B. Schmidt, W. Skorupa, G. Gobsch, and M. Helm Superconducting Ga-rich layers in Ge are fabricated by Ga implantation through a thin SiO 2 cover layer. After annealing in a certain temperature window, Ga accumulation at the SiO 2 /Ge interface is observed. However, no Ga-containing crystalline phases are identified. Thus it is suggested that the vo... [Phys. Rev. B 85, 134530] Published Fri Apr 27, 2012
    Keywords: Superfluidity and superconductivity
    Print ISSN: 1098-0121
    Electronic ISSN: 1095-3795
    Topics: Physics
    Published by American Physical Society (APS)
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  • 4
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    On the horizontal and temporal structure of noctilucent clouds as observed by satellite and lidar at ALOMAR (69N) (2012)
    Wiley
    Details
    Publication Date: 2012-01-05
    Description: Simultaneous and common volume observations of Noctilucent Clouds (NLC) and Polar Mesospheric Clouds (PMC) have been performed above the ALOMAR research station in Northern Norway (69°N, 16°E) from ground and space, respectively. A detailed case study on August 5, 2008 shows that the measured particle sizes and T-matrix simulations of the optical properties allow to combine the two observation techniques. From the ground, the observations were performed by lidar sounding of the temporal evolution of the cloud at two locations separated by about 40 km, before, during and after the coincidence. From space, the CIPS instrument onboard the AIM satellite observed the horizontal structure of the cloud. Using mesospheric radar wind measurements at ALOMAR the advection of the cloud particles is calculated and the temporal evolution of the cloud as seen from ground is compared with the horizontal structure observed from satellite. This comparison allows estimation of the timescales during which the clouds behave as passive tracers. We find that during this case study cloud structures larger than about 5 km × 5 km and oscillations slower than about one minute behaved like a passive tracer for up to one hour corresponding to horizontal scales of about 300 km. However, if the cloud shows wave structures with brightness modulations of 20% microphysical changes might take place on scales of minutes and kilometers.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 5
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    MicroRNA-21 contributes to myocardial disease by stimulating MAP kinase signalling in fibroblasts (2008)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2008-12-02
    Description: MicroRNAs comprise a broad class of small non-coding RNAs that control expression of complementary target messenger RNAs. Dysregulation of microRNAs by several mechanisms has been described in various disease states including cardiac disease. Whereas previous studies of cardiac disease have focused on microRNAs that are primarily expressed in cardiomyocytes, the role of microRNAs expressed in other cell types of the heart is unclear. Here we show that microRNA-21 (miR-21, also known as Mirn21) regulates the ERK-MAP kinase signalling pathway in cardiac fibroblasts, which has impacts on global cardiac structure and function. miR-21 levels are increased selectively in fibroblasts of the failing heart, augmenting ERK-MAP kinase activity through inhibition of sprouty homologue 1 (Spry1). This mechanism regulates fibroblast survival and growth factor secretion, apparently controlling the extent of interstitial fibrosis and cardiac hypertrophy. In vivo silencing of miR-21 by a specific antagomir in a mouse pressure-overload-induced disease model reduces cardiac ERK-MAP kinase activity, inhibits interstitial fibrosis and attenuates cardiac dysfunction. These findings reveal that microRNAs can contribute to myocardial disease by an effect in cardiac fibroblasts. Our results validate miR-21 as a disease target in heart failure and establish the therapeutic efficacy of microRNA therapeutic intervention in a cardiovascular disease setting.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Thum, Thomas -- Gross, Carina -- Fiedler, Jan -- Fischer, Thomas -- Kissler, Stephan -- Bussen, Markus -- Galuppo, Paolo -- Just, Steffen -- Rottbauer, Wolfgang -- Frantz, Stefan -- Castoldi, Mirco -- Soutschek, Jurgen -- Koteliansky, Victor -- Rosenwald, Andreas -- Basson, M Albert -- Licht, Jonathan D -- Pena, John T R -- Rouhanifard, Sara H -- Muckenthaler, Martina U -- Tuschl, Thomas -- Martin, Gail R -- Bauersachs, Johann -- Engelhardt, Stefan -- R01 CA059998/CA/NCI NIH HHS/ -- R01 CA78711/CA/NCI NIH HHS/ -- England -- Nature. 2008 Dec 18;456(7224):980-4. doi: 10.1038/nature07511. Epub 2008 Nov 30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine I, Interdisziplinares Zentrum fur Klinische Forschung (IZKF), University of Wuerzburg, 97080 Wuerzburg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19043405" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cardiomyopathies/*genetics/*metabolism/pathology/therapy ; Cell Line ; Cell Survival ; Cells, Cultured ; Disease Models, Animal ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Fibroblasts/*metabolism ; Gene Silencing ; Humans ; *MAP Kinase Signaling System ; Male ; Mice ; Mice, Transgenic ; MicroRNAs/*genetics ; Myocytes, Cardiac/cytology/metabolism ; Rats
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 6
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    From a non-magnet to a ferromagnet: Mn+ implantation into different TiO2 structures (2015)
    American Institute of Physics (AIP)
    Details
    Publication Date: 2015-12-16
    Description: We report effect of the initial structural order on the resulting magnetic properties of manganese implanted TiO 2 films. Different microstructures of as-grown TiO 2 films, namely, amorphous, polycrystalline anatase, and epitaxial anatase, have been implant-doped with Mn + up to a concentration of 5 at. %. We found that different initial structures lead to different defect and charge carrier concentrations and, as a result, strongly influence the magnetic properties upon implantation. Depending on the initial microstructure, paramagnetism, secondary phases related magnetic properties as well as ferromagnetism could be observed in the films.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Published by American Institute of Physics (AIP)
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  • 7
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    High-fluence Ga-implanted silicon—The effect of annealing and cover layers (2014)
    American Institute of Physics (AIP)
    Details
    Publication Date: 2014-07-09
    Description: The influence of SiO 2 and SiN x cover layers on the dopant distribution as well as microstructure of high fluence Ga implanted Si after thermal processing is investigated. The annealing temperature determines the layer microstructure and the cover layers influence the obtained Ga profile. Rapid thermal annealing at temperatures up to 750 °C leads to a polycrystalline layer structure containing amorphous Ga-rich precipitates. Already after a short 20 ms flash lamp annealing, a Ga-rich interface layer is observed for implantation through the cover layers. This effect can partly be suppressed by annealing temperatures of at least 900 °C. However, in this case, Ga accumulates in larger, cone-like precipitates without disturbing the surrounding Si lattice parameters. Such a Ga-rich crystalline Si phase does not exist in the equilibrium phase diagram according to which the Ga solubility in Si is less than 0.1 at. %. The Ga-rich areas are capped with SiO x grown during annealing which only can be avoided by the usage of SiN x cover layers.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Published by American Institute of Physics (AIP)
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  • 8
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    Optical study of superconducting Ga-rich layers in silicon (2013)
    American Physical Society (APS)
    Details
    Publication Date: 2013-01-03
    Description: Author(s): T. Fischer, A. V. Pronin, R. Skrotzki, T. Herrmannsdörfer, J. Wosnitza, J. Fiedler, V. Heera, M. Helm, and E. Schachinger We performed phase-sensitive terahertz (0.12–1.2 THz) transmission measurements of Ga-enriched layers in silicon. Below the superconducting transition T c middle =6.7 K we find clear signatures of the formation of a superconducting condensate and of the opening of an energy gap in the optical spectra. ... [Phys. Rev. B 87, 014502] Published Wed Jan 02, 2013
    Keywords: Superfluidity and superconductivity
    Print ISSN: 1098-0121
    Electronic ISSN: 1095-3795
    Topics: Physics
    Published by American Physical Society (APS)
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  • 9
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    Materials, Vol. 11, Pages 1413: Fused Particle Fabrication 3-D Printing: Recycled Materials’ Optimization and Mechanical Properties (2018)
    MDPI Publishing
    In: Materials
    Details
    Publication Date: 2018-08-13
    Description: Materials, Vol. 11, Pages 1413: Fused Particle Fabrication 3-D Printing: Recycled Materials’ Optimization and Mechanical Properties Materials doi: 10.3390/ma11081413 Authors: Aubrey L. Woern Dennis J. Byard Robert B. Oakley Matthew J. Fiedler Samantha L. Snabes Joshua M. Pearce Fused particle fabrication (FPF) (or fused granular fabrication (FGF)) has potential for increasing recycled polymers in 3-D printing. Here, the open source Gigabot X is used to develop a new method to optimize FPF/FGF for recycled materials. Virgin polylactic acid (PLA) pellets and prints were analyzed and were then compared to four recycled polymers including the two most popular printing materials (PLA and acrylonitrile butadiene styrene (ABS)) as well as the two most common waste plastics (polyethylene terephthalate (PET) and polypropylene (PP)). The size characteristics of the various materials were quantified using digital image processing. Then, power and nozzle velocity matrices were used to optimize the print speed, and a print test was used to maximize the output for a two-temperature stage extruder for a given polymer feedstock. ASTM type 4 tensile tests were used to determine the mechanical properties of each plastic when they were printed with a particle drive extruder system and were compared with filament printing. The results showed that the Gigabot X can print materials 6.5× to 13× faster than conventional printers depending on the material, with no significant reduction in the mechanical properties. It was concluded that the Gigabot X and similar FPF/FGF printers can utilize a wide range of recycled polymer materials with minimal post processing.
    Electronic ISSN: 1996-1944
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by MDPI Publishing
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  • 10
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    Optimizing Manufacturing and Osseointegration of Ti6Al4V Implants through Precision Casting and Calcium and Phosphorus Ion Implantation? In Vivo Results of a Large-Scale Animal Trial (2020)
    Molecular Diversity Preservation International
    Details
    Publication Date: 2020-04-03
    Description: Background: Uncemented implants are still associated with several major challenges, especially with regard to their manufacturing and their osseointegration. In this study, a novel manufacturing technique—an optimized form of precision casting—and a novel surface modification to promote osseointegration—calcium and phosphorus ion implantation into the implant surface—were tested in vivo. Methods: Cylindrical Ti6Al4V implants were inserted bilaterally into the tibia of 110 rats. We compared two generations of cast Ti6Al4V implants (CAST 1st GEN, n = 22, and CAST 2nd GEN, n = 22) as well as cast 2nd GEN Ti6Al4V implants with calcium (CAST + CA, n = 22) and phosphorus (CAST + P, n = 22) ion implantation to standard machined Ti6Al4V implants (control, n = 22). After 4 and 12 weeks, maximal pull-out force and bone-to-implant contact rate (BIC) were measured and compared between all five groups. Results: There was no significant difference between all five groups after 4 weeks or 12 weeks with regard to pull-out force (p 〉 0.05, Kruskal Wallis test). Histomorphometric analysis showed no significant difference of BIC after 4 weeks (p 〉 0.05, Kruskal–Wallis test), whereas there was a trend towards a higher BIC in the CAST + P group (54.8% ± 15.2%), especially compared to the control group (38.6% ± 12.8%) after 12 weeks (p = 0.053, Kruskal–Wallis test). Conclusion: In this study, we found no indication of inferiority of Ti6Al4V implants cast with the optimized centrifugal precision casting technique of the second generation compared to standard Ti6Al4V implants. As the employed manufacturing process holds considerable economic potential, mainly due to a significantly decreased material demand per implant by casting near net-shape instead of milling away most of the starting ingot, its application in manufacturing uncemented implants seems promising. However, no significant advantages of calcium or phosphorus ion implantation could be observed in this study. Due to the promising results of ion implantation in previous in vitro and in vivo studies, further in vivo studies with different ion implantation conditions should be considered.
    Electronic ISSN: 1996-1944
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Molecular Diversity Preservation International
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