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81.
There has been interest for a number of years in the possibility of separating blood into cells and plasma by methods other than centrifugation, so that the plasma can be analysed on-line. Cells in whole blood normally occupy about 45% of the suspension volume. It has been shown with a number of different cell types, such as yeast and bacteria, that for concentrations of this order the cells are not as efficiently harvested by ultrasound as those for lower concentrations. In this study, removal of cells from 3-4 ml whole blood volumes has been examined in ultrasonic standing wave fields from tubular transducers driven at a frequency of 1.6 MHz. Samples of whole human blood (n = 11) from two volunteers have been processed by three tubular transducers where high levels of cell removal, 99.7% on average, have been demonstrated with high reproducibility between samples as well as for different transducers. 相似文献
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83.
Shipman MA Price C Elsegood MR Clegg W Houlton A 《Angewandte Chemie (International ed. in English)》2000,39(13):2360-2362
84.
We compare several heuristics for solving a single machine scheduling problem. In the operating situation modelled, setup times are sequence-dependent and the objective is to minimize total tardiness. We describe an Ant Colony Optimization (ACO) algorithm having a new feature using look-ahead information in the transition rule. This feature shows an improvement in performance. A comparison with a genetic algorithm, a simulated annealing approach, a local search method and a branch-and-bound algorithm indicates that the ACO that we describe is competitive and has a certain advantage for larger problems. 相似文献
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Theodore?J?Price Michael?D?Louria Damaries?Candelario-Soto Gregory?O?Dussor Nathanial?A?Jeske Amol?M?Patwardhan Anibal?Diogenes Amanda?A?Trott Kenneth?M?Hargreaves Christopher?M?FloresEmail author 《BMC neuroscience》2005,6(1):4
Background
Nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) all play important roles in the development of the peripheral sensory nervous system. Additionally, these growth factors are proposed to modulate the properties of the sensory system in the adult under pathological conditions brought about by nerve injury or inflammation. We have examined the effects of NGF, GDNF and BDNF on adult rat trigeminal ganglion (TG) neurons in culture to gain a better understanding of how these growth factors alter the cytochemical and functional phenotype of these neurons, with special attention to properties associated with nociception. 相似文献88.
The normal growth rates and slopes of the dominant growth spirals on a crystal face were measured using a novel application of interferometry and atomic force microscopy. The dislocations responsible for the spirals were also observed directly. In this way it was shown that the velocities of similar steps on growth spirals of different activity, growing simultaneously on the same crystal face, were the same, and hence independent of the growth spirals to which they belonged. With this information the relative activities of the spirals were quantified and discussed in terms of hollow dislocation cores and the back-stress effect. 相似文献
89.
Chaotic behavior of a Galerkin model of the Kolmogorov fluid motion equations is demonstrated. The study focuses on the dynamical behavior of limit trajectories branching off secondary periodic solutions. It is shown that four limit trajectories exist and transform simultaneously from periodic solutions to chaotic attractors through a sequence of bifurcations including a periodic-doubling scenario. Some instability regimes display close similarities to those of a discrete dynamical system generated by an interval map. 相似文献
90.
Synthesis of protected tetradehydro-(6,6'-S)-(14,14'-S)-(16,16'-R)-disorazole (3), a potential precursor to the natural product disorazole C1 (1), is described. Key features of this work include (a) an unprecedented sequential 1,5 O --> O silyl rearrangement/Horner-Wadsworth-Emmons reaction used to construct 18, (b) a highly convergent Sonogashira reaction between the dienyl iodide 7 and the alkyne 8 to assemble the dienyne monomeric fragment 5, and (c) the selective cyclization of 5 to give either the cyclic monomer 23 or the dimer 3. 相似文献