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| Articles
by
Yu Chen |
Total Records (
3 ) for
Yu Chen |
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Xinling Wen
and
Yu Chen
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The Blind Source Separation (BSS) algorithm has got more and more attention in signal processing field. Among the BSS algorithm, the natural gradient algorithm is one of the important method. This study mainly introduces the way of the natural gradient algorithm and realizes an application in the speech signal processing. Through the experiment, when the iteration of 60 times, the natural gradient algorithm on the speech signal separation can realize convergence and the steady-state string sound error approaches to zero which proving the good separation results based on the gradient algorithm on the speech signal separation. |
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Li Jiang
,
Junmei Fan
,
Li Bai
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Yan Wang
,
Yu Chen
,
Lu Yang
,
Liangyi Chen
and
Tao Xu
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Insulin-stimulated GLUT4 translocation to the plasma membrane constitutes a key process for blood glucose control. However, convenient and robust assays to monitor this dynamic process in real time are lacking, which hinders current progress toward elucidation of the underlying molecular events as well as screens for drugs targeting this particular pathway. Here, we have developed a novel dual colored probe to monitor the translocation process of GLUT4 based on dual color fluorescence measurement. We demonstrate that this probe is more than an order of magnitude more sensitive than the current technology for detecting fusion events from single GLUT4 storage vesicles (GSVs). A small fraction of fusion events were found to be of the "kiss-and-run" type. For the first time, we show that insulin stimulation evokes a ~40-fold increase in the fusion of GSVs in 3T3-L1 adipocytes, compared with basal conditions. The probe can also be used to monitor the prefusion behavior of GSVs. By quantifying both the docking and fusion rates simultaneously, we demonstrate a proportional inhibition in both docking and fusion of GSVs by a dominant negative mutant of AS160, indicating a role for AS160 in the docking of GSVs but not in the regulation of GSV fusion after docking. |
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Ross Corriden
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Yu Chen
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Yoshiaki Inoue
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Guido Beldi
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Simon C. Robson
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Paul A. Insel
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Wolfgang G. Junger
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Polymorphonuclear neutrophils release ATP in response to stimulation by chemoattractants, such as the peptide N-formyl-methionyl-leucyl-phenylalanine. Released ATP and the hydrolytic product adenosine regulate chemotaxis of neutrophils by sequentially activating purinergic nucleotide and adenosine receptors, respectively. Here we show that that ecto-nucleoside triphosphate diphosphohydrolase 1 (E-NTPDase1, CD39) is a critical enzyme for hydrolysis of released ATP by neutrophils and for cell migration in response to multiple agonists (N-formyl-methionyl-leucyl-phenylalanine, interleukin-8, and C5a). Upon stimulation of human neutrophils or differentiated HL-60 cells in a chemotactic gradient, E-NTPDase1 tightly associates with the leading edge of polarized cells during chemotaxis. Inhibition of E-NTPDase1 reduces the migration speed of neutrophils but not their ability to detect the orientation of the gradient field. Studies of neutrophils from E-NTPDase1 knock-out mice reveal similar impairments of chemotaxis in vitro and in vivo. Thus, E-NTPDase1 plays an important role in regulating neutrophil chemotaxis by facilitating the hydrolysis of extracellular ATP. |
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