Qiang Zhang

Qiang Zhang

Instructor of Medicine

Washington University in St. Louis

Biography

Qiang Zhang is a researcher at Washington University in St. Louis. His research interests include mass spectrometry-based proteomics and automation in data analysis.

Interests

  • Mass spectrometry
  • R programming

Education

  • PhD in Physical Chemistry, 2003

    University of California - Santa Barbara

  • Master in Physical Chemistry, 1998

    Xiamen University

  • BSc in Physical Chemistry, 1995

    Xiamen University

Experience

 
 
 
 
 

Instructor

Washington University in St. Louis

Dec 2015 – Present Missouri
Proteomics, data analysis and R programming
 
 
 
 
 

Senior/Principal Scientist

Mead Johnson Nutrition

Jun 2008 – Nov 2015 Indiana
Group head in mass spectrometry and proteomics
 
 
 
 
 

Postdoctoral/Research scientist

Washington University in St. Louis

Dec 2004 – Jun 2008 Missouri
Biomedical mass spectrometry
 
 
 
 
 

Postdoctoral researcher

University of California - Santa Barbara

Jul 2003 – Nov 2004 California
Instrumentation in mass spectrometry

Recent Posts

Understanding the Benjamini–Hochberg procedure

The prnSig and pepSig utilities in proteoQ perform significance analysis for protein and peptide data, respectively. In what follows the step of p-value assessment, multiple test corrections using the stats::p.

Interfaces to search engines

I have shown previously some unique aspects in exporting PSMs from Mascot, for uses with proteoQ. In this post, I will do the same for more search engines, e.

Exporting Mascot PSMs

Redundancy handling When exporting Mascot PSMs, one choice is to apply upfrontly the principle of parsimony by excluding both same-set and sub-set proteins (2011) whose presence may not be unambiguously determined.

Metadata files for LFQ

The LFQ workflows in proteoQ take the same metadata files as those with TMT procedures; namely, expt_smry.xlsx and frac_smry.xlsx by default. No prefractionation For experiments without peptide prefractionation, we only need to prepare the expt_smry.

LDA in proteoQ

\[\newcommand{\mx}[1]{\mathbf{#1}} \def\pone{\mathbf{\mathbf{\phi}}_{1}} \def\ponet{\mathbf{\mathbf{\phi}}_{1}^{T}} \def\phat{\hat{\phi}_{1}} \def\X{\mathbf{X}} \def\Xt{\mathbf{X}^{T}} \def\y{\mathbf{y}} \def\A{\mathbf{A}} \def\B{\mathbf{B}} \def\W{\mathbf{W}} \def\argmax{\mathrm{arg\, max}} \def\argmaxphii{\underset{\left \| \pone \right \|=1}{\argmax}}\] Linear discriminant analysis (LDA) is popular for both the classification and the dimension reduction of data at two or more categories.

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