McFadden Forrest (batporch9)

Protein phosphorylation regulates the conformations and function of proteins, which plays an important part in organisms. However, systematic and in-depth analysis of phosphorylation often hinders on account of the low abundance and suppressed ionization of phosphopeptides. Various materials based on single enrichment mechanism show potential in phosphopeptides enrichment, but the enrichment performance is typically not satisfactory. Herein, we developed a carnosine (Car) functionalized magnetic metal organic framework designed as Fe3O4@NH2@ZIF-90@Car. Benefiting from the multiple recognition groups of Car and massive metal ions site of ZIF-90, the as-fabricated Fe3O4@NH2@ZIF-90@Car was utilized as a multifunctional material with synergistic effect for phosphopeptides enrichment. On the basis of combined immobilized metal ion affinity chromatography (IMAC) and amine-based affinity enrichment mechanism, Fe3O4@NH2@ZIF-90@Car exhibited higher enrichment performance of phosphopeptides compared with Fe3O4@NH2@ZIF-90 (single IMAC mechanism). Besides, the feasibility of Fe3O4@NH2@ZIF-90@Car nanocomposites in complicated samples was further verified by enriching phosphopeptides from nonfat milk, human fluids such as serum and saliva, demonstrating its bright application prospects in phosphoproteomics analysis.In this fundamental research, we found that homo-oligo based dsDNA holds potential electrochemical characteristics in comparison to hetero-oligo based dsDNA which can be exploited in voltammetric and impedimetric biosensors. We prepared a homo-oligo based dsDNA from 20 deoxyribonucleotides of adenine, guanine, cytosine, and thymine (A20, G20, C20, and T20 respectively) and a hetero-oligo based dsDNA from two partially complementary oligos (5'-TTT TTT CAT CTA TCA ACA TCA GTC TGA TAA GCT ATA GAA GC-3' and 5'-TTT TTT ATA GCT TTG ATA GA-3'. Electrochemical impedance spectroscopy in 1 mM 0.1 M K3[Fe(CN)6]/KCl showed that Au working electrode modified with hetero-oligo based dsDNA (Au/hetero-oligo-dsDNA) was more resistive toward charge transfer of Fe(CN)63-/4- compared to Au working electrode modified with homo-oligo based dsDNA (Au/homo-oligo-dsDNA). Additionally, cyclic voltammetry and linear sweep voltammetry showed that Au/homo-oligo-dsDNA produced quantifiable anodic and cathodic peak currents which were not observed for Au/hetero-oligo-dsDNA. Nyquist and Bode plots derived from electrochemical impedance spectroscopy on three different electroactive areas (0.0705, 0.0747 and 0.0837 cm2) of Au working electrode showed no significant change in the capacitive behavior of Au/homo-oligo-dsDNA and Au/hetero-oligo-dsDNA in a linear range of frequency (10-100 Hz).We have all been confronted one day by saturated signals observed on acquired spectra, whatever the technique considered. A saturation, also known as clipping in signal processing, is a form of distortion that limits a signal once it exceeds a threshold. As a consequence, clipped or saturated bands with their characteristic plateau present numerical values that do not correspond to the analytical reality of the analyzed sample. Of course, analysts know that they cannot consider these erroneous values and therefore reconsider either sample preparation or instrument settings. Unfortunately, there are many experiments today (and this is the case in spectroscopic imaging) for which we will not be able to fight against the saturation effect that will undeniably be observed on the acquired spectra. The aim of this article is first to show why it is important to correct these saturation effects at the risk of having a biased view of the sample and more specifically in the context of multivariate data analysis. In a second step, we will look at strategies for managing saturated bands. An original concept will then be presented by considering saturated values as missing ones. A statistical imputation strategy will then be implemented in order to recover the information lost during the