A model of bubble coalescence in the presence of a nonionic surfactant with a low bubble approach velocity

A bubble coalescence model for a solution with a nonionic surfactant and with a small bubble approach velocity was developed, in which the mechanism of how coalescence is hindered by Marangoni stress was quantitatively analyzed. The bubble coalescence time calculated for ethanol-water and MIBC-water systems were in good agreement with experimental data. At low surfactant concentrations, the Marangoni stress and bubble coalescence time increased with bulk concentration increase. Conversely, in the high concentration range, the Marangoni stress and coalescence time decreased with bulk concentration. Numerical results showed that the nonlinear relationship between coalescence time and surfactant concentration is determined by the mass transport flux between the film and its interface, which tends to diminish the spatial concentration variation of the interface, i.e., it acts as a “damper”. This damping effect increases with increased surfactant concentration, therefore decreasing the coalescence time at high concentrations.

Development and comparison of UPLC-ESI-MS and RP-HPLC-VWD methods for determining microcystin-LR

UPLC-MS and HPLC-VWD methods were used together for MC-LR determination in a wide concentration range. UPLC-MS can be applied in trace MC-LR determination, whereas HPLC-VWD is more suitable for high concentration range detection.

Pyrene-based aggregation-induced emission luminogens (AIEgens) with less colour migration for anti-counterfeiting applications

A series of pyrene-based AIEgens have been employed in the preparation of fluorescent inks with less colour migration for anti-counterfeiting applications over the ultra-low to high concentration range and avoids the ACQ effect.

Kinetics of simultaneous degradation of 4-bromophenol and 4-chlorophenol by Arthrobacter chlorophenolicusA6

Biodegradation of p-bromophenol (4-BP) along with p-chlorophenol (4-CP) was investigated in batch shake flasks using a actinomycetes strain of Arthrobacterchlorophenolicus A6. A Two level full factorial design at two different levels (low and high) was applied to perform the biodegradation of 4-CP and 4-BP in the mixed substrate system. Result reveals that the presence of 4-CP in low concentration range in the mixture (20–60 mgl-1) did not inhibit 4-BP biodegradation by the actinomycetes. However, at high concentration range of 4-CP (100-200 mgl-1), the 4-BP biodegradation was inhibited. Further, 4-BP degradation was faster than 4-CP. In order to study variation in the specific degradation rate of these pollutants and their interaction effect exist between them, the experimental data were fitted to a sum kinetics model. The experimental data have been fitted with the model with a high correlation coefficient value (R2> 0.94). The model fitted data reveals a strong negative interaction effect of 4-CP on biodegradation of 4-BP by the A. chlorophenolicusA6.

A Polar Liquid Zwitterion Does Not Critically Destroy Cytochrome c at High Concentration: An Initial Comparative Study with a Polar Ionic Liquid

A polar carboxylate-type zwitterion with a small volume of water can dissolve cytochrome c without significant disruption, compared with the case of a popular polar carboxylate-type ionic liquid, 1-ethyl-3-methylimidazolium acetate. A change in the Soret, Q, and 615nm bands was not observed in the 80 wt-% polar zwitterion solution, whereas a shift in the Soret band, diminishing Q band, and appearance of the 615nm band was found in the 80 wt-% polar ionic liquid solution. It suggests that concentrated polar ionic liquid solutions critically disrupt the structure of cytochrome c, and the polar zwitterion solution used in this study was better than a 1-ethyl-3-methylimidazolium acetate solution in a high concentration range.

Precision, accuracy, cross reactivity and comparability of serum indices measurement on Abbott Architect c8000, Beckman Coulter AU5800 and Roche Cobas 6000 c501 clinical chemistry analyzers

Background:The aim of our study was to perform verification of serum indices on three clinical chemistry platforms.Methods:This study was done on three analyzers: Abbott Architect c8000, Beckman Coulter AU5800 (BC) and Roche Cobas 6000 c501. The following analytical specifications were verified: precision (two patient samples), accuracy (sample with the highest concentration of interferent was serially diluted and measured values compared to theoretical values), comparability (120 patients samples) and cross reactivity (samples with increasing concentrations of interferent were divided in two aliquots and remaining interferents were added in each aliquot. Measurements were done before and after adding interferents).Results:Best results for precision were obtained for the H index (0.72%–2.08%). Accuracy for the H index was acceptable for Cobas and BC, while on Architect, deviations in the high concentration range were observed (y=0.02 [0.01–0.07]+1.07 [1.06–1.08]x). All three analyzers showed acceptable results in evaluating accuracy of L index and unacceptable results for I index. The H index was comparable between BC and both, Architect (Cohen’s κ [95% CI]=0.795 [0.692–0.898]) and Roche (Cohen’s κ [95% CI]=0.825 [0.729–0.922]), while Roche and Architect were not comparable. The I index was not comparable between all analyzer combinations, while the L index was only comparable between Abbott and BC. Cross reactivity analysis mostly showed that serum indices measurement is affected when a combination of interferences is present.Conclusions:There is heterogeneity between analyzers in the hemolysis, icteria, lipemia (HIL) quality performance. Verification of serum indices in routine work is necessary to establish analytical specifications.

Functional Asymmetries in Cockroach ON and OFF Olfactory Receptor Neurons

The ON and OFF olfactory receptor neurons (ORNs) on the antenna of the American cockroach respond to the same changes in the concentration of the odor of lemon oil, but in the opposite direction. The same jump in concentration raises impulse frequency in the ON and lowers it in the OFF ORN and, conversely, the same concentration drop raises impulse frequency in the OFF and lowers it in the ON ORN. When the new concentration level is maintained, it becomes a background concentration and affects the responses of the ON and OFF ORNs to superimposed changes. Raising the background concentration decreases both the ON-ORN's response to concentration jumps and the OFF-ORN's response to concentration drops. In addition, the slopes of the functions approximating the relationship of impulse frequency to concentration changes become flatter for both types of ORNs as the background concentration rises. The progressively compressed scaling optimizes the detection of concentration changes in the low concentration range. The loss of information caused by the lower differential sensitivity in the high concentration range is partially compensated by the higher discharge rates of the OFF ORNs. The functional asymmetry of the ON and OFF ORNs, which reflects nonlinearity in the detection of changes in the concentration of the lemon oil odor, improves information transfer for decrements in the high concentration range.