Proton exchange membranes with short-pathway through-plane orientated proton conductivity are highly desirable for use in proton exchange membrane fuel cells. Magnetic field is utilized to create ...oriented structure in proton exchange membranes. Previously, this has only been carried out by proton nonconductive metal oxide-based fillers. Here, under a strong magnetic field, a proton-conducting paramagnetic complex based on ferrocyanide-coordinated polymer and phosphotungstic acid is used to prepare composite membranes with highly conductive through-plane-aligned proton channels. Gratifyingly, this strategy simultaneously overcomes the high water-solubility of phosphotungstic acid in composite membranes, thereby preventing its leaching and the subsequent loss of membrane conductivity. The ferrocyanide groups in the coordinated polymer, via redox cycle, can continuously consume free radicals, thus helping to improve the long-term in situ membrane durability. The composite membranes exhibit outstanding proton conductivity, fuel cell performance and durability, compared with other types of hydrocarbon membranes and industry standard Nafion
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Between 1944 and 1953, a power struggle emerged between New York governor Thomas Dewey and U.S. senator Robert Taft of Ohio that threatened to split the Republican Party. InThe Roots of Modern ...Conservatism, Michael Bowen reveals how this two-man battle for control of the GOP--and the Republican presidential nomination--escalated into a divide of ideology that ultimately determined the party's political identity.Initially, Bowen argues, the separate Dewey and Taft factions endorsed fairly traditional Republican policies. However, as their conflict deepened, the normally mundane issues of political factions, such as patronage and fund-raising, were overshadowed by the question of what "true" Republicanism meant. Taft emerged as the more conservative of the two leaders, while Dewey viewed Taft's policies as outdated. Eventually, conservatives within the GOP organized against Dewey's leadership and, emboldened by the election of Dwight Eisenhower, transformed the party into a vehicle for the Right. Bowen reveals how this decade-long battle led to an outpouring of conservative sentiment that had been building since World War II, setting the stage for the ascendancy of Barry Goldwater and the modern conservative movement in the 1960s.
Liquid metal elastomer (LME)—that is, liquid metal particles dispersed in elastomer—is a soft material that has useful electric, dielectric, and thermal properties. Two issues with LME are sought to ...be addressed: 1) the dense liquid metal (LM) particles can settle before curing of the elastomer, and 2) the LM particles are separated by a thin layer of insulating elastomer and therefore require some “mechanical sintering” to break this layer to create conductive paths. These issues are addressed using an LME containing elastic particles (LMEP). Elastic polydimethylsiloxane particles (PPs) and LM particles jam to prevent particle settling. Meanwhile, the PPs reduce the loading necessary to create conductive paths, thus decreasing the density and cost relative to LME. Surprisingly, the particles percolate into conductive paths prior to curing the LMEP but not in LME. The dielectric constant, electrical conductivity, and thermal conductivity of LMEPs are investigated by changing the volume fraction of LM particles, polydimethylsiloxane pre‐polymer and PPs, and propose an LMEP with the optimal ratio. In addition, LMEP‐based sensors and circuits are demonstrated for wearable electronics.
Liquid metal elastomer (LME) has useful electric, dielectric, and thermal properties. While, the dense liquid metal (LM) particles can settle before curing the elastomer decreases the above properties. This problem is addressed by using an LME containing elastic particles (LMEP). Elastic polydimethylsiloxane particles and LM particles jam to prevent particle settling. The dielectric constant, electrical conductivity, and thermal conductivity of LMEPs are investigated by changing the volume fraction. In addition, LMEP‐based sensors and circuits are demonstrated for wearable electronics.
Cholestatic liver diseases result from impaired bile flow and are characterized by inflammation, atypical ductular proliferation, and fibrosis. The Wnt/β‐catenin pathway plays a role in bile duct ...development, yet its role in cholestatic injury remains indeterminate. Liver‐specific β‐catenin knockout mice and wild‐type littermates were subjected to cholestatic injury through bile duct ligation or short‐term exposure to 3,5‐diethoxycarbonyl‐1,4‐dihydrocollidine diet. Intriguingly, knockout mice exhibit a dramatic protection from liver injury, fibrosis, and atypical ductular proliferation, which coincides with significantly decreased total hepatic bile acids (BAs). This led to the discovery of a role for β‐catenin in regulating BA synthesis and transport through regulation of farnesoid X receptor (FXR) activation. We show that β‐catenin functions as both an inhibitor of nuclear translocation and a nuclear corepressor through formation of a physical complex with FXR. Loss of β‐catenin expedited FXR nuclear localization and FXR/retinoic X receptor alpha association, culminating in small heterodimer protein promoter occupancy and activation in response to BA or FXR agonist. Conversely, accumulation of β‐catenin sequesters FXR, thus inhibiting its activation. Finally, exogenous suppression of β‐catenin expression during cholestatic injury reduces β‐catenin/FXR complex activation of FXR to decrease total BA and alleviate hepatic injury. Conclusion: We have identified an FXR/β‐catenin interaction whose modulation through β‐catenin suppression promotes FXR activation and decreases hepatic BAs, which may provide unique therapeutic opportunities in cholestatic liver diseases. (Hepatology 2018;67:955–971)
Abstract
Parker Solar Probe observes unexpectedly prevalent switchbacks, which are rapid magnetic field reversals that last from seconds to hours, in the inner heliosphere, posing new challenges to ...understanding their nature, origin, and evolution. In this work, we investigate the thermal states, electron pitch-angle distributions, and pressure signatures of both inside and outside the switchbacks, separating a switchback into spike, transition region (TR), and quiet period (QP). Based on our analysis, we find that the proton temperature anisotropies in TRs seem to show an intermediate state between spike and QP plasmas. The proton temperatures are more enhanced in the spike than in the TR and QP, but the alpha temperatures and alpha-to-proton temperature ratios show the opposite trend to the proton temperatures, implying that the preferential heating mechanisms of protons and alphas are competing in different regions of switchbacks. Moreover, our results suggest that the electron-integrated intensities are almost the same across the switchbacks, but the electron pitch-angle distributions are more isotropic inside than outside switchbacks, implying switchbacks are intact structures, but strong scattering of electrons happens inside switchbacks. In addition, the examination of pressures reveals that the total pressures are comparable through an individual switchback, confirming switchbacks are pressure-balanced structures. These characteristics could further our understanding of ion heating, electron scattering, and the structure of switchbacks.
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