Boolean sums of sets of certain designs

In this note the author applies Boolean sum operation on sets of certain designs to get new series of designs.     

Proton Medium Effect Based on the Ferrocinium Assumption in 80 Mass-% Propylene Carbonate + 20 Mass-% <Emphasis Type="Italic">p</Emphasis>-Xylene Medium

Conventional electrochemical studies on the ferrocinium–ferrocene (Fc⁺–Fc) redox system in 80 mass-% propylene carbonate (PC) + 20 mass-% p-xylene (PX) medium are reported, leading to a calculation of the proton medium effect. The dissociation constant of ferrocinium picrate in this medium was determined by conductivity measurements. The value of E_{Fe⁺ /Fe}^oE_{\mathrm{Fe^{+} /Fe}}^{\mathrm{o}} against the Hg/HgCl₂(s) reference electrode in 80 mass-% PC + 20 mass-% PX was determined potentiometrically in conjunction with conductivity data, and found to be 0.133±0.001 V versus the SHE at 25 °C. The E_{Fe⁺ /Fe}^oE_{\mathrm{Fe^{+} /Fe}}^{\mathrm{o}} value has also been calculated using cyclic voltammetric data obtained in 80 mass-% PC + 20 mass-% PX at a micro platinum working electrode against the Ag/AgCl (nonaq.) reference electrode, and found to be comparable with the value obtained by potentiometry. The proton medium effect for transfer from water to the present mixed solvent medium was calculated using the value of E_Fe⁺/Fe^oE_{\mathrm{Fe^{+}/Fe}}^{\mathrm{o}} versus SHE at 25 °C and found to be 4.5. Based on values of proton medium effect reported in the literature, it is inferred that the present mixed solvent medium is slightly more basic than pure PC.     

A study of reproducibility of guanidination-dimethylation labeling and liquid chromatography matrix-assisted laser desorption ionization mass spectrometry for relative proteome quantification

The combination of dimethylation after guanidination (2MEGA) isotope labeling with microbore liquid chromatography (LC)-matrix-assisted laser desorption ionization (MALDI) MS and MS/MS [C. Ji, N. Guo, L. Li, J. Proteome Res. 4 (2005) 2099] has been reported as a promising strategy for abundance ratio-dependent quantitative proteome analysis. A critical step in using this integrated strategy is to set up the abundance ratio threshold of peptide pairs, above which the peptide pairs are used for quantifying and identifying the protein that is considered to be differentially expressed between two different samples. The threshold is determined by technical variation (i.e., the overall abundance ratio variation caused by the experimental process including sample workup, MS analysis and data processing) as well as biological variation (i.e., the abundance ratio variation caused by the biological process including cell growth), which can be defined and assessed by a coefficient of variation (CV). We have designed experiments and measured three different levels of variations, starting with the same membrane protein preparation, the same batch of cells and three batches of cells from the same cell line grown under the same conditions, respectively. It is shown that technical variation from the experimental processes involved in 2MEGA labeling LC-MALDI MS has a CV of <15%. In addition, the measured biological variation from cell growth was much smaller than the measured technical variation. From the studies of the occurrence rate of outliers in the distribution of the abundance ratio data within a comparative dataset of peptide pairs, it is concluded that, to compare the proteome changes between two sets of cultured cells without the use of replicate experiments, a relative abundance ratio of greater than 2X or less than 0.5X (X is the average abundance ratio of the dataset) on peptide pairs can be used as a stringent threshold to quantify and identify differentially expressed proteins with high confidence.     

Prudent Practices in ex situ Durability Analysis Using Cyclic Voltammetry for Platinum-based Electrocatalysts

Platinum (Pt)-based electrocatalysts are at the vanguard of research initiatives to meet activity and durability targets for promoting large-scale adoption of fuel cell vehicles. Ex situ characterization of electrocatalyst activity and durability using cyclic voltammetry (CV) has a steep learning curve. Thus, many researchers who do not receive formal training in electrochemistry are left unsure how to proceed. Herein, we identify and compile prudent practices for reliable assessment of ECSA values with examples from our research on nanoscale catalytic films formed by the self-terminating electrodeposition of Pt. Starting with a conceptual framework to understand typical features in the CV of reversible redox couples, we present prudent practices in acquiring CV data aimed at nonelectrochemists. We then highlight specific features related to ECSA computation from Pt CV. Finally, we suggest safeguards that help avoid missteps and achieve repeatable results while conducting ex situ durability tests that extend over days.     

Establishment of a Hydrogen Scale in 80 Mass % Propylene Carbonate + <Emphasis Type="Italic">p</Emphasis>-Xylene Medium

Details of the standardization of the reference electrode Hg/HgCl_2(s) versus the SHE by a potentiometric method using two acids (viz., perchloric and 2,5-dichlorobenzene-sulfonic acids) in 80 mass % propylene carbonate (PC) + p-xylene (PX), are presented. Using this reference electrode, the standard electrode potential of the quinhydrone electrode was determined in this medium. The reference electrode potential and the standard electrode potential of the quinhydrone electrode were found to be (0.277±0.003) and (0.760±0.003) V versus SHE in 80 mass % PC + PX at 25 °C, respectively. The voltammetric behavior of the quinhydrone system in this medium was investigated at a micro platinum electrode against a non-aqueous double-junction Ag/AgCl reference electrode. The standard electrode potential of the quinhydrone system was also calculated using voltammetric and chronocoulometric data that is comparable with the value obtained by potentiometry.