Behavior of Poly electrolyte Gels in Concentrated Solutions of Highly Soluble Salts

Ionic hydrogels are an abundant class of materials with applications ranging from drug delivery devices to high performance concrete to baby diapers. A more thorough understanding of interactions between poly electrolyte networks and ionic solutes is critical as these materials are further tailored for performance applications in highly targeted ionic environments. In this work, we seek to develop structure-property relationships between polyelectrolyte gels and environments containing high concentrations of multivalent ions. Specifically, this work seeks to elucidate the causes behind differences in hydrogel response to divalent ions of main group metals versus transition metals. PANa-co-PAM hydrogels containing low and high fractions of ionic groups are investigated in solutions of DI water, NaCl, CaCl2, and CuSO4 at concentrations ranging from 5 to 100 mM in order to understand 1) the transient or permanent nature of crosslinks produced in these networks by divalent counter-ions, 2) the role of polymer ionic content in these interactions, and 3) how these interactions scale with salt concentration. Gravimetric swelling and mechanical compression testing are employed to characterize water and salt-swollen hydrogels in order to develop guiding principles to control and manipulate material properties through polymer-counter-ion interactions. The work presented here confirms the formation of permanent crosslinks by transition metal ions, offers explanation for the behavioral discrepancy observed between ionic hydrogels and main group versus transition metal ions, and illustrates how such hydrogel properties scale with counter-ion concentration

Statistical Algorithms with Phase-Sensitive Detection for the Number of Hovers and S Turns in Aircraft Flights

Compared to maximum state parameters, such as maximum altitude and Mach, the number of hovers and S turns can be used as process parameters representing the complexity of military aircraft maneuvers when classifying big flight mission data to compile flight load spectra for structures. This study developed intelligent statistical algorithms based on yaw angle data from flight parameters such as the number of hovers and S turns. Using the median-crossing de-redundant function of Phase-Sensitive Detection (PSD) and analyzing the characteristics of 360° hovering flight parameters, a statistical algorithm for the number of hovers during a flight profile is presented. Using the split-half function of PSD, a triangle layering algorithm based on the yaw angle signal was developed to count the number of S turns during a flight profile, where the signal of each sublayer is segmented into median-crossing intervals to eliminate the redundant median-crossing marks from the previous layer. Compared with artificial means, the statistical results of the flight example showed that the developed intelligent algorithms are effective

Redox modification of CLOCK mediates the regulatory function of endogenous H2O2 in mouse cellular respiration

Objective To explore the mechanisms of transcription factor circadian locomalor output cycles kaput(CLOCK) in mediating regulatory function of endogenous hydrogen peroxide(H2O2) for cell respiration. Methods Cellular oxygen consumption capacity and glycolysis in ClockC195S mouse embryonic fibroblasts (MEFs) and adult fibroblasts(MAFs) were tested by Agilent Seahorse XF Cell Mito Stress Test Kit and Glycolysis Stress Test Kit. The expression of key genes participating in cell respiration was detected by q-PCR. The endogenous H2O2 levels and the redox modification of CLOCK were detected by Amplex® Red Hydrogen Peroxide/Peroxidase Assay Kit and biotin-conjugated iodoacetamide (BIAM) were used respectively after the treatment of antioxidant Trolox. Changes in the oxygen consumption capacity and in key respiratory gene expression after the treatment of antioxidant Trolox were also tested in Clockwt and ClockC195S MEFs. Results Cellular oxygen consumption capacity, glycolysis and the expression of NMNAT2, a key enzyme in nicotinamide adenine denudeotide(NAD) biosynthesis, as well as NAD content all decreased in ClockC195S MEFs. The treatment with Trolox decreased endogenous H2O2 level and dampened respiration capacity in Clockwt MEFs but not in ClockC195S MEFs. Conclusions CLOCK mediates the regulation of endogenous H2O2 for cellular respiration through its redox modification at Cys195