K. John Wu

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Matrix-assisted laser desorption time-of-flight mass spectrometry has been used to produce quasi-molecular ion signals from underivatized mixed-base single-stranded DNA oligomers ranging from 10 to 67 nucleotides in length. These results were obtained with a new matrix material, 3-hydroxypicolinic acid (3-hydroxypyridine-2-carboxylic acid) which showed(More)
Matrix-assisted laser desorption with concomitant ionization (MALDI) in conjunction with time-of-flight mass spectrometry (TOF-MS) has been used to analyze underivatized random-base single-stranded DNA (ssDNA) oligomers ranging from 10 to 89 nucleotides in length by embedding them in a solid matrix of 3-hydroxypicolinic acid. At 355-nm desorption(More)
The effect of impurities on the analysis of single-stranded DNA oligomers by the technique of matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry has been studied using the matrix 3-hydroxypicolinic acid and 355-nm pulsed light. By mixing the DNA oligomers with different concentrations of impurities and recording mass spectra,(More)
Extreme precipitation events on the western coast of North America are often traced to an unusual weather phenomenon known as atmospheric rivers. Although these storms may provide a significant fraction of the total water to the highly managed western US hydrological system, the resulting intense weather poses severe risks to the human and natural(More)
Adaptive Mesh Refinement (AMR) is a highly effective method for simulations spanning a large range of spatiotemporal scales such as those encountered in astrophysical simulations. Combining research in novel AMR visu-alization algorithms and basic infrastructure work, the Department of Energy's (DOEs) Science Discovery through Advanced Computing (SciDAC)(More)
Studies relating the magnesium (Mg) content of calcified skeletons to temperature often report unexplained deviations from the signature expected for inorganically grown calcite. These "vital effects" are believed to have biological origins, but mechanistic bases for measured offsets remain unclear. We show that a simple hydrophilic peptide, with the same(More)
Protein identification is an important objective for proteomic and medical sciences as well as for pharmaceutical industry. With recent large-scale automation of genome sequencing and the explosion of protein databases, it is important to exploit latest data processing technologies and design highly scalable algorithms to speed up protein identification. In(More)
–This paper presents a new method for theoretical stability analysis of a bidirectional dual full bridge DC-DC converter with triple phase-shift control. The developed approach is analytically sound and generally applicable when compared with the existing approaches, which are by and large based on computer simulation. The operating process of a(More)
Ferulic acid, sinapinic acid and 2,5-dihydroxybenzoic acid (DHBA) have been tested as matrix materials for matrix-assisted laser desorption of the pure oligonucleotide pd(T)12 and a mixture of oligonucleotides pd(T)12 through pd(T)18 using pulsed 337 nm radiation combined with reflecting time-of-flight mass spectrometry. The three matrix materials are(More)