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191.
Paul Langlais Lawrence J. Mandarino Zhengping Yi 《Journal of the American Society for Mass Spectrometry》2010,21(9):1490-1499
Intracellular signal transduction is often regulated by transient protein phosphorylation in response to external stimuli.
Insulin signaling is dependent on specific protein phosphorylation events, and analysis of insulin receptor substrate-1 (IRS-1)
phosphorylation reveals a complex interplay between tyrosine, serine, and threonine phosphorylation. The phosphospecific antibody-based
quantification approach for analyzing changes in site-specific phosphorylation of IRS-1 is difficult due to the dearth of
phospho-antibodies compared with the large number of known IRS-1 phosphorylation sites. We previously published a method detailing
a peak area-based mass spectrometry approach, using precursor ions for peptides, to quantify the relative abundance of site-specific
phosphorylation in the absence or presence of insulin. We now present an improvement wherein site-specific phosphorylation
is quantified by determining the peak area of fragment ions respective to the phospho-site of interest. This provides the
advantage of being able to quantify co-eluting isobaric phosphopeptides (differentially phosphorylated versions of the same
peptide), allowing for a more comprehensive analysis of protein phosphorylation. Quantifying human IRS-1 phosphorylation sites
at Ser303, Ser323, Ser330, Ser348, Ser527, and Ser531 shows that this method is linear (n = 3; r2 = 0.85 ± 0.05, 0.96 ± 0.01, 0.96 ± 0.02, 0.86 ± 0.07, 0.90 ± 0.03, 0.91 ± 0.04, respectively) over an approximate 10-fold
range of concentrations and reproducible (n = 4; coefficient of variation = 0.12, 0.14, 0.29, 0.30, 0.12, 0.06, respectively). This application of label-free, fragment
ion-based quantification to assess relative phosphorylation changes of specific proteins will prove useful for understanding
how various cell stimuli regulate protein function by phosphorylation. 相似文献
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The different approaches that have been taken in the development of analytical methods for the determination of nitrate within the field are reviewed. The emphasis has been placed on providing a critical appraisal of the chemistry that underpins current commercial systems and the need to remove the dependence on heavy metal and concentrated acid components. The search for more environmentally acceptable and user friendly systems has long been pursued and the present communication seeks to explore the recent development in portable testing technologies and how they might evolve in the future. In particular, the role of electrochemical techniques in the latter are investigated and their potential application compared and contrasted with the more traditional wet chemical detection strategies. 相似文献
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Potvin Alfred R. Crosier William G. Fromm Eli Lin James C. Neuman Michael R. Pilkington Theo C. Robinson Charles J. Schneider Lawrence W. Strohbehn John W. Szolovits Peter Tompkins Willis J. 《IEEE transactions on bio-medical engineering》1986,(1):48-59
MORE than 200 years ago, our forefathers made note of man's inalienable rights to life, liberty, and the pursuit of happiness. To the engineering community (applied science in the service of man), these may be coincident with applications to medicine and biology (biomedical engineering), defense, and entertainment. Biomedical engineering research has the distinction, among these three missions, of not only contributing to the quality of human life through the industrial economy but also to life itself?the most fundamental concern of all people. It is through biomedical engineering research that we have been able to learn much concerning the functioning of living systems, and it is through such knowledge that we have been able to develop improved clinical diagnosis, monitoring, and treatment, including life-sustaining devices and aids to the handicapped. Each step represents an improvement in the quality of life, and each step forms the foundation upon which to gain new knowledge to improve upon earlier developments. 相似文献
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Michael Lawrence Hadley Wickham Dianne Cook Heike Hofmann Deborah F. Swayne 《Computational Statistics》2009,24(2):195-205
This paper describes progress towards developing a platform for rapid prototyping of interactive data visualizations, using
R, GGobi, rggobi and RGtk2. GGobi is a software tool for multivariate interactive graphics. At the core of GGobi is a data
pipeline that incrementally transforms data through a series of stages into a plot and maps user interaction with the plot
back to the data. The GGobi pipeline is extensible and mutable at runtime. The rggobi package, an interface from the R language
to GGobi, has been augmented with a low-level interface that supports the customization of interactive data visualizations
through the extension and manipulation of the GGobi pipeline. The large size of the GGobi API has motivated the use of the
RGtk2 code generation system to create the low-level interface between R and GGobi. The software is demonstrated through an
application to interactive network visualization. 相似文献