The stable formation of PurR hinge helices requires PurR dimerization, which brings the hinge regions proximal to each other. The dimerization of the hinge helices is likely to be controlled by the CBD dimerization interface, but is induced by specific-DNA binding.

No abstract

Expanding the range of supercapacitor operation to temperatures above 100°C is important because this would enable capacitors to operate under the severe conditions required for next-generation energy storage devices. In this study, we address this challenge by the fabrication of a solid-state supercapacitor with a proton-conducting Sn0.95Al0.05H0.05P2O7 (SAPO)-polytetrafluoroethylene (PTFE) composite electrolyte and a highly condensed H3PO4 electrode ionomer. At a temperature of 200°C, the SAPO-PTFE electrolyte exhibits a high proton conductivity of 0.02 S cm−1 and a wide withstanding voltage range of ±2 V. The H3PO4 ionomer also has good wettability with micropore-rich activated carbon, which realizes a capacitance of 210 F g−1 at 200°C. The resulting supercapacitor exhibits an energy density of 32 Wh kg−1 at 3 A g−1 and stable cyclability after 7000 cycles from room temperature to 150°C.

Proton-conducting composite membranes were fabricated by blending Sn 0.95 Al 0.05 P 2 O 7 having an excess of phosphates with polybenzimidazole ͑PBI͒ and polytetrafluoroethylene ͑PTFE͒. The addition of PBI to Sn 0.95 Al 0.05 P 2 O 7 -P x O y powder stabilized the conductivity of the composite, providing higher conductivities than those of stoichiometric Sn 0.95 Al 0.05 P 2 O 7 . The addition of PTFE to Sn 0.95 Al 0.05 P 2 O 7 -P x O y -PBI powder reduced the conductivity but increased the tensile strength. The resulting composite membrane exhibited a conductivity of 0.04 S cm −1 at 200°C and a tensile strength of 2.30 MPa. Moreover, a fuel cell made with this composite membrane yielded high power densities exceeding 200 mW cm −2 above 100°C and good durability under unhumidified conditions. Proton conductors capable of operating at 100-250°C are currently of great interest because of their advantages over Nafion-type fluoropolymers that are conventionally used at temperatures of 80°C or less in proton exchange membrane fuel cells. 1,2 Operating a fuel cell at intermediate temperatures provides the anode catalyst with a high tolerance to CO, eliminating the need for a CO-removal unit ͑water-gas-shift and CO-preferential-oxidation reactors͒. In addition, the kinetics of the electrode kinetics are enhanced at intermediate temperatures, permitting low Pt loadings. Other advantages include good drainage at the cathode and effective heat dissipation.Because anhydrous proton conductors do not require the presence of water as the charge carrier, they can be operated at intermediate temperatures ͑at least in principle͒. In addition, anhydrous proton conductors potentially can make proton conductivity independent of humidity so that a complicated humidity control system is not required. Thus, considerable effort has been devoted to developing anhydrous proton conductors. Although a number of anhydrous proton conductors have already been developed, their proton conductivities have been reported to be in the range of 10 −2 -10 −3 S cm −1 . [3][4][5][6][7][8][9][10] We previously reported that 10 mol % In 3+ -or 5 mol % Al 3+ -doped SnP 2 O 7 exhibited high proton conductivities of above 10 −1 S cm −1 between 100 and 300°C in water-free conditions. 11,12 These materials were also investigated for use as electrolytes in intermediate-temperature fuel cells. These fuel cells exhibited stable performance in low-humidity conditions and high CO concentrations; 13 they also permitted the use of alternative anodes to Pt 14 and had good fuel flexibility. 15 In a series of studies, excess P was observed as a highly hygroscopic P x O y layer on the exterior of the crystal, when the H 3 PO 4 /MO x ͑M = Sn and Al͒ molar ratio of the raw materials was much higher than its stoichiometric value. 12 The resulting conductivity reached 0.3 S cm −1 at 275°C, which is approximately 2 times higher than that of the stoichiometric Al 3+ -doped SnP 2 O 7 ͑hereafter Sn 0.95 Al 0.05 P 2 O 7 ͒ at the same temperature. This increase in conductivity was d...

Biomass has been considered as an alternative feedstock for energy and material supply. However, the lack of high-efficiency and low-cost processes for biomass utilization and conversion hinders its large-scale application. This report describes electrochemical hydrogen production from waste biomass that does not require large amounts of energy or high production costs. Hydrogen was produced by the electrolysis of bread residue, cypress sawdust, and rice chaff at an onset cell voltage of ca. 0.3 V, with high current efficiencies of approximately 100% for hydrogen production at the cathode and approximately 90% for carbon dioxide production at the anode. The hydrogen yields per 1 mg of the raw material were 0.1−0.2 mg for all tested fuels. Electrolysis proceeded continuously at plateau voltages that were proportional to the current. These characteristics were attributable to the high catalytic activity of the carbonyl-group functionalized mesoporous carbon for the anode reaction, and that the major components of biomass such as cellulose, starch, lignin, protein, and lipid were effectively utilized as fuels for hydrogen production.