http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
An unconventional role for miRNA: let-7 activates Toll-like receptor 7 and causes neurodegeneration
Lehmann, Sabrina M,Kr체ger, Christina,Park, Boyoun,Derkow, Katja,Rosenberger, Karen,Baumgart, Jan,Trimbuch, Thorsten,Eom, Gina,Hinz, Michael,Kaul, David,Habbel, Piet,K채lin, Roland,Franzoni, Eleonora,Ry Nature Publishing Group, a division of Macmillan P 2012 NATURE NEUROSCIENCE Vol.15 No.6
Activation of innate immune receptors by host-derived factors exacerbates CNS damage, but the identity of these factors remains elusive. We uncovered an unconventional role for the microRNA let-7, a highly abundant regulator of gene expression in the CNS, in which extracellular let-7 activates the RNA-sensing Toll-like receptor (TLR) 7 and induces neurodegeneration through neuronal TLR7. Cerebrospinal fluid (CSF) from individuals with Alzheimer's disease contains increased amounts of let-7b, and extracellular introduction of let-7b into the CSF of wild-type mice by intrathecal injection resulted in neurodegeneration. Mice lacking TLR7 were resistant to this neurodegenerative effect, but this susceptibility to let-7 was restored in neurons transfected with TLR7 by intrauterine electroporation of Tlr7<SUP>??/??</SUP> fetuses. Our results suggest that microRNAs can function as signaling molecules and identify TLR7 as an essential element in a pathway that contributes to the spread of CNS damage.
Lehmann, C. I.,Kim, Y.-H.,Preusse, P.,Chun, H.-Y.,Ern, M.,Kim, S.-Y. Copernicus GmbH 2012 Atmospheric measurement techniques Vol.5 No.7
<P><p><strong>Abstract.</strong> Convective gravity wave (GW) sources are spatially localized and emit at the same time waves with a wide spectrum of phase speeds. Any wave analysis therefore compromises between spectral and spatial resolution. Future satellite borne limb imagers will for a first time provide real 3-D volumes of observations. These volumes will be however limited which will impose further constraints on the analysis technique. In this study a three dimensional few-wave approach fitting sinusoidal waves to limited 3-D volumes is introduced. The method is applied to simulated GWs above typhoon Ewiniar and GW momentum flux is estimated from temperature fluctuations. Phase speed spectra as well as average profiles of positive, negative and net momentum fluxes are compared to momentum flux estimated by Fourier transform as well as spatial averaging of wind fluctuations. The results agree within 10-20%. The few-wave method can also reveal the spatial orientation of the GWs with respect to the source. The relevance of the results for different types of measurements as well as its applicability to model data is discussed.</p> </P>
An effective finite element approach for soil-structure analysis in the time-domain
Lehmann, L. Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.21 No.4
In this study, a complete analysis of soil-structure interaction problems is presented which includes a modelling of the near surrounding of the building (near-field) and a special description of the wave propagation process in larger distances (far-field). In order to reduce the computational effort which can be very high for time domain analysis of wave propagation problems, a special approach based on similarity transformation of the infinite domain on the near-field/far-field interface is applied for the wave radiation of the far-field. The near-field is discretised with standard Finite Elements, which also allows to introduce non-linear material behaviour. In this paper, a new approach to calculate the involved convolution integrals is presented. This approximation in time leads to a dramatically reduced computational effort for long simulation times, while the accuracy of the method is not affected. Finally, some benchmark examples are presented, which are compared to a coupled Finite Element/Boundary Element approach. The results are in excellent agreement with those of the coupled Finite Element/Boundary Element procedure, while the accuracy is not reduced. Furthermore, the presented approach is easy to incorporate in any Finite Element code, so the practical relevance is high.
Strategic Interactions on structural Reforms Between Intergrated Economies: What Lessons for the EU?
Etienne Lehmann,Emmanuelle Taugourdeau 세종대학교 경제통합연구소 2004 Journal of Economic Integration Vol.19 No.1
We show that the domestic output increases with a foreign country's structural reform and decreases with foreign country’s fiscal policy. Hence, when governments act non-cooperatively, they implement too low structural reforms and too much fiscal policies. We show that the domestic output increases with a foreign country's structural reform and decreases with foreign country’s fiscal policy. Hence, when governments act non-cooperatively, they implement too low structural reforms and too much fiscal policies.
An effective finite element approach for soil-structure analysis in the time-domain
L. Lehmann 국제구조공학회 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.21 No.4
In this study, a complete analysis of soil-structure interaction problems is presented which includes a modelling of the near surrounding of the building (near-field) and a special description of the wave propagation process in larger distances (far-field). In order to reduce the computational effort which can be very high for time domain analysis of wave propagation problems, a special approach based on similarity transformation of the infinite domain on the near-field/far-field interface is applied for the wave radiation of the far-field. The near-field is discretised with standard Finite Elements, which also allows to introduce non-linear material behaviour. In this paper, a new approach to calculate the involved convolution integrals is presented. This approximation in time leads to a dramatically reduced computational effort for long simulation times, while the accuracy of the method is not affected. Finally, some benchmark examples are presented, which are compared to a coupled Finite Element/Boundary Element approach. The results are in excellent agreement with those of the coupled Finite Element/Boundary Element procedure, while the accuracy is not reduced. Furthermore, the presented approach is easy to incorporate in any Finite Element code, so the practical relevance is high.