http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A comparison of DAE integrators in the context of benchmark problems for flexible multibody dynamics
Peter Betsch,Christian Becker,Marlon Franke,Yinping Yang,Alexander Janz 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.7
In the present work a uniform framework for general flexible multibody dynamics is used to compare state-of-the-art DAE integratorsin the context of benchmark problems. The multibody systems considered herein are comprised of rigid bodies, nonlinear beams andshells. The constitutive laws applied in the benchmark problems belong to the class of hyperelastic materials. To numerically integratethe uniform set of DAEs three alternative time-stepping schemes are applied: (i) an energy-momentum consistent method, (ii) a specificvariational integrator and (iii) a generalized-α scheme.
Multiparameter fluorescence image spectroscopy to study molecular interactions
Weidtkamp-Peters, Stefanie,Felekyan, Suren,Bleckmann, Andrea,Simon, Rudiger,Becker, Wolfgang,Kuhnemuth, Ralf,Seidel, Claus A.M. Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.4
Multiparameter Fluorescence Image Spectroscopy (MFIS) is used to monitor simultaneously a variety of fluorescence parameters in confocal fluorescence microscopy. As the photons are registered one by one, MFIS allows for fully parallel recording of Fluorescence Correlation/Cross Correlation Spectroscopy (FCS/FCCS), fluorescence lifetime and pixel/image information over time periods of hours with picosecond accuracy. The analysis of the pixel fluorescence information in higher-dimensional histograms maximizes the selectivity of fluorescence microscopic methods. Moreover it facilitates a statistically-relevant data analysis of the pixel information which makes an efficient detection of heterogeneities possible. The reliability of MFIS has been demonstrated for molecular interaction studies in different complex environments: (I) detecting the heterogeneity of diffusion properties of the dye Rhodamine 110 in a sepharose bead, (II) F$\ddot{o}$rster Resonance Energy Transfer (FRET) studies in mammalian HEK293 cells, and (III) FRET study of the homodimerisation of the transcription factor BIM1 in plant cells. The multidimensional analysis of correlated changes of several parameters measured by FRET, FCS, fluorescence lifetime and anisotropy increases the robustness of the analysis significantly. The economic use of photon information allows one to keep the expression levels of fluorescent protein-fusion proteins as low as possible (down to the single-molecule level).
DYNAMICAL STRUCTURE OF VISCOUS ACCRETION DISKS WITH SHOCKS
Das, Santabrata,Becker, Peter A.,Le, Truong IOP Publishing 2009 The Astrophysical journal Vol.702 No.1
<P>We develop and discuss global accretion solutions for viscous advection-dominated accretion flow (ADAF) disks containing centrifugally supported isothermal shock waves. The fact that such shocks can exist at all in ADAF disks is a new result. Interestingly, we find that isothermal shocks can form even when the level of viscous dissipation is relatively high. In order to better understand this phenomenon, we explore all possible combinations of the fundamental flow parameters, such as specific energy, specific angular momentum, and viscosity, to obtain the complete family of global solutions. This procedure allows us to identify the region of the parameter space where isothermal shocks can exist in viscous ADAF disks. The allowed region is maximized in the inviscid case, and it shrinks as the level of viscous dissipation increases. Adopting the canonical value gamma = 1.5 for the ratio of specific heats, we find that the shock region disappears completely when the Shakura-Sunyaev viscosity parameter alpha exceeds the critical value similar to 0.27. This establishes for the first time that steady ADAF disks containing shocks can exist even for relatively high levels of viscous dissipation. If an isothermal shock is present in the disk, it would have important implications for the acceleration of energetic particles that can escape to power the relativistic jets commonly observed around underfed, radio-loud black holes. In two specific applications, we confirm that the kinetic luminosity lost from the disk at the isothermal shock location is sufficient to power the observed relativistic outflows in M87 and Sgr A*.</P>
A miRNA181a/NFAT5 axis links impaired T cell tolerance induction with autoimmune type 1 diabetes
Serr, Isabelle,Scherm, Martin G.,Zahm, Adam M.,Schug, Jonathan,Flynn, Victoria K.,Hippich, Markus,Kalin, Stefanie,Becker, Maike,Achenbach, Peter,Nikolaev, Alexei,Gerlach, Katharina,Liebsch, Nicole,Lor American Association for the Advancement of Scienc 2018 Science Translational Medicine Vol.10 No.422
<P>Molecular checkpoints that trigger the onset of islet autoimmunity or progression to human type 1 diabetes (T1D) are incompletely understood. Using T cells from children at an early stage of islet autoimmunity without clinical T1D, we find that a microRNA181a (miRNA181a)-mediated increase in signal strength of stimulation and costimulation links nuclear factor of activated T cells 5 (NFAT5) with impaired tolerance induction and autoimmune activation. We show that enhancing miRNA181a activity increases NFAT5 expression while inhibiting FOXP3+ regulatory T cell (T-reg) induction in vitro. Accordingly, Treg induction is improved using T cells from NFAT5 knockout (NFAT5ko) animals, whereas altering miRNA181a activity does not affect T-reg induction in NFAT5ko T cells. Moreover, high costimulatory signals result in phosphoinositide 3-kinase (PI3K)-mediated NFAT5, which interferes with FoxP(3+) Treg induction. Blocking miRNA181a or NFAT5 increases Treg induction in murine and humanized models and reduces murine islet autoimmunity in vivo. These findings suggest targeting miRNA181a and/or NFAT5 signaling for the development of innovative personalized medicines to limit islet autoimmunity.</P>