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Mixing Experiments (mixing + experiment)
Selected AbstractsCell autonomous sorting and surface positioning in the formation of primitive endoderm in embryoid bodies,GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 6 2007Malgorzata E. Rula Abstract The differentiation and formation of the primitive endoderm in early embryos can be mimicked in vitro by the aggregation of embryonic stem cells to form embryoid bodies. We present morphological evidence that primitive endoderm cells often first locate in the interior of embryoid bodies and subsequently migrate to the surface. Cell mixing experiments indicate that surface positioning is an intrinsic property of endoderm epithelial cells. Moreover, Disabled-2 (Dab2) is required for surface sorting and positioning of the endoderm cells: when Dab2 expression was eliminated, the differentiated endoderm epithelial cells distributed throughout the interior of the embryoid bodies. Surprisingly, E-cadherin is dispensable for primitive endoderm differentiation and surface sorting in embryoid bodies. These results support the model that primitive endoderm cells first emerge in the interior of the inner cell mass and are subsequently sorted to the surface to form the primitive endoderm. genesis 45: 327,338, 2007. Published 2007 Wiley-Liss, Inc. [source] Hyperchaotic signal generation via DSP for efficient perturbations to liquid mixingINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 1 2009Zhong Zhang Abstract This paper presents the design, simulation, hardware implementation and an application in liquid mixing of some hyperchaotic circuits, based on the digital signal processing (DSP) technology. The hyperchaotic Chen's system is used as an example to show the system discretization and variable renormalization in the design process. Numerical simulation is given to verify the hardware signal generator. The implemented hardware of Chen's system generates outputs in good agreement with the numerical simulation. The hyperchaotic signal output from the DSP is applied to generate complex perturbations in liquid mixing experiments. Dye dispersion experiments show that the induced hyperchaotic motion effectively helps enhance the mixing homogeneity in the stirred-tank-based mixer in our laboratory. Copyright © 2008 John Wiley & Sons, Ltd. [source] Deagglomeration of nanoparticle aggregates via rapid expansion of supercritical or high-pressure suspensionsAICHE JOURNAL, Issue 11 2009Daniel To Abstract Deagglomeration of suspensions of alumina and titania nanopowders (i.e., nanoparticle aggregates) via rapid expansion of supercritical suspensions (RESS) or high-pressure suspensions (REHPS) was studied. The size distribution of fragmented nanopowders was characterized by online Scanning Mobility Particle Spectrometer (SMPS) and Aerodynamic Particle Sizer (APS), and by offline Scanning Electron Microscopy (SEM). SMPS and SEM measurements indicate that the average agglomerate sizes were well below 1 ,m, consistent with the length scales observed in our complementary RESS/REHPS mixing experiments using alumina and silica nanopowders. The APS measurements, on the other hand, were affected by reagglomeration during sampling and yielded an agglomerate size range of 1 to 3 ,m. Analysis of the RESS/REHPS process through compressible flow models revealed that both the shear stress in the nozzle and the subsequent impact of the agglomerates with the Mach disc in the free expansion region can lead to micron or sub-micron level deagglomeration. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] 4-Alkylbenzopyrylium perchlorates as C,H Acidic compoundsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 7 2002U.-W. Grummt Abstract 7-Alkyl-5,6-dihydro-3-methoxy(naphtho[1,2b]-1-benzopyrylium) compounds are acidochromic due to CH acidity of the 7-alkyl substituent. Their acidity exponents are 4 < pKa < 5 and 1 < pKa < 3 regardless of whether the carbocation generated by deprotonation is resonance stabilized by a phenyl substituent or not. The thermodynamic equilibrium data were obtained via UV,vis spectroscopy. The activation parameters for protonation and deprotonation reactions were derived from rapid mixing experiments. Ab initio calculations with model compounds are presented in order to rationalize the experimental findings. The title compounds are useful objects to study the kinetics of proton-transfer kinetics to and from carbon. Copyright © 2002 John Wiley & Sons, Ltd. [source] | ||||||||||