Kinetic Study of the Thermopolymerization of Furfuryl Methacrylate (FM) by Mathematical Modeling, 2–Moments of Molecular Size Distribution of the Primary Chains in the Networks

The formation kinetics and structure of three‐dimensional networks in free radical polymerization of FM thermally initiated at high temperature are studied by analysis of zero and first‐order moments of molecular size distribution of primary chains (MSDPC) in the networks. Zero‐order moment values of MSDPC reveal that the system elapses as a living radical polymerization. Also, by means of the analysis of these moments and the first‐order ones of MSDPC, the sigmoidal shape of polymerization kinetic curves can be explained. On the other hand, the results of average crosslink density obtained using moment values of MSDPC suggest that this parameter does not change with polymerization temperature.

     

Fully automated isotopic dimethyl labeling and phosphopeptide enrichment using a microfluidic HPLC phosphochip

Quantitative detection of phosphorylation levels is challenging and requires an expertise in both stable isotope labeling as well as enrichment of phosphorylated peptides. Recently, a microfluidic device incorporating a nanoliter flow rate reversed phase column as well as a titania (TiO₂) enrichment column was released. This HPLC phosphochip allows excellent recovery and separation of phosphorylated peptides in a robust and reproducible manner with little user intervention. In this work, we have extended the abilities of this chip by defining the conditions required for on-chip stable isotope dimethyl labeling allowing for automated quantitation. The resulting approach will make quantitative phosphoproteomics more accessible.

Combined infrared multiphoton dissociation and electron-capture dissociation using co-linear and overlapping beams in Fourier transform ion cyclotron resonance mass spectrometry

A novel set-up for Fourier transform ion cyclotron resonance mass spectrometry (FTICR) is reported for simultaneous infrared multiphoton dissociation (IRMPD) and electron-capture dissociation (ECD). An unmodified electron gun ensures complete, on-axis overlap between the electron and the photon beams. The instrumentation, design and implementation of this novel approach are described. In this configuration the IR beam is directed into the ICR cell using a pneumatically actuated mirror inserted into the ion-optical path. Concept validation was made using different combinations of IRMPD and ECD irradiation events on two standard peptides. The ability to perform efficient IRMPD, ECD and especially simultaneous IRMPD and ECD using lower irradiation times is demonstrated. The increase in primary sequence coverage, with the combined IRMPD and ECD set-up, also increases the confidence in peptide and protein assignments.     

Lp Lq Estimates for Parabolic Systems in Non-Divergence Form with VMO Coefficients

Consider a parabolic NxN-system of order m on ⁿ with top-ordercoefficients a VMOL. Let 1 < p, q < and let be a Muckenhouptweight. It is proved that systems of this kind possess a uniquesolution u satisfying whereAu = _||m a Du and J = [0,). In particular, choosing = 1, therealization of A in L^p(ⁿ)^N has maximal L^p – L^q regularity.