Recent theoretical proposals suggest that strain can be used to engineer graphene electronic states through the creation of a pseudo-magnetic field. This effect is unique to graphene because of its ...massless Dirac fermion-like band structure and particular lattice symmetry (C₃v). Here, we present experimental spectroscopic measurements by scanning tunneling microscopy of highly strained nanobubbles that form when graphene is grown on a platinum (111) surface. The nanobubbles exhibit Landau levels that form in the presence of strain-induced pseudo-magnetic fields greater than 300 tesla. This demonstration of enormous pseudo-magnetic fields opens the door to both the study of charge carriers in previously inaccessible high magnetic field regimes and deliberate mechanical control over electronic structure in graphene or so-called "strain engineering."
This article provides an overview of the current and projected climate change risks and impacts to mental health and provides recommendations for priority actions to address the mental health ...consequences of climate change.
The authors argue the following three points: firstly, while attribution of mental health outcomes to specific climate change risks remains challenging, there are a number of opportunities available to advance the field of mental health and climate change with more empirical research in this domain; secondly, the risks and impacts of climate change on mental health are already rapidly accelerating, resulting in a number of direct, indirect, and overarching effects that disproportionally affect those who are most marginalized; and, thirdly, interventions to address climate change and mental health need to be coordinated and rooted in active hope in order to tackle the problem in a holistic manner. This discussion paper concludes with recommendations for priority actions to address the mental health consequences of climate change.
Cobalt oxides and (oxy)hydroxides have been widely studied as electrocatalysts for the oxygen evolution reaction (OER). For related Ni-based materials, the addition of Fe dramatically enhances OER ...activity. The role of Fe in Co-based materials is not well-documented. We show that the intrinsic OER activity of Co1–x Fe x (OOH) is ∼100-fold higher for x ≈ 0.6–0.7 than for x = 0 on a per-metal turnover frequency basis. Fe-free CoOOH absorbs Fe from electrolyte impurities if the electrolyte is not rigorously purified. Fe incorporation and increased activity correlate with an anodic shift in the nominally Co2+/3+ redox wave, indicating strong electronic interactions between the two elements and likely substitutional doping of Fe for Co. In situ electrical measurements show that Co1–x Fe x (OOH) is conductive under OER conditions (∼0.7–4 mS cm–1 at ∼300 mV overpotential), but that FeOOH is an insulator with measurable conductivity (2.2 × 10–2 mS cm–1) only at high overpotentials >400 mV. The apparent OER activity of FeOOH is thus limited by low conductivity. Microbalance measurements show that films with x ≥ 0.54 (i.e., Fe-rich) dissolve in 1 M KOH electrolyte under OER conditions. For x < 0.54, the films appear chemically stable, but the OER activity decreases by 16–62% over 2 h, likely due to conversion into denser, oxide-like phases. We thus hypothesize that Fe is the most-active site in the catalyst, while CoOOH primarily provides a conductive, high-surface area, chemically stabilizing host. These results are important as Fe-containing Co- and Ni-(oxy)hydroxides are the fastest OER catalysts known.
Using archival Very Long Baseline Interferometry (VLBI) data for 3114 radio-luminous active galactic nuclei, we searched for binary supermassive black holes using a radio spectral index mapping ...technique which targets spatially resolved, double radio-emitting nuclei. Only one source was detected as a double nucleus. This result is compared with a cosmological merger rate model and interpreted in terms of (1) implications for post-merger time-scales for centralization of the two black holes, (2) implications for the possibility of 'stalled' systems and (3) the relationship of radio activity in nuclei to mergers. Our analysis suggests that binary pair evolution of supermassive black holes (both of masses ≥108 M⊙) spends less than 500 Myr in progression from the merging of galactic stellar cores to within the purported stalling radius for supermassive black hole pairs. The data show no evidence for an excess of stalled binary systems at small separations. We see circumstantial evidence that the relative state of radio emission between paired supermassive black holes is correlated within orbital separations of 2.5 kpc.
Better understanding of the dynamics of the current U.S. overdose epidemic may aid in the development of more effective prevention and control strategies. We analyzed records of 599,255 deaths from ...1979 through 2016 from the National Vital Statistics System in which accidental drug poisoning was identified as the main cause of death. By examining all available data on accidental poisoning deaths back to 1979 and showing that the overall 38-year curve is exponential, we provide evidence that the current wave of opioid overdose deaths (due to prescription opioids, heroin, and fentanyl) may just be the latest manifestation of a more fundamental longer-term process. The 38+ year smooth exponential curve of total U.S. annual accidental drug poisoning deaths is a composite of multiple distinctive subepidemics of different drugs (primarily prescription opioids, heroin, methadone, synthetic opioids, cocaine, and methamphetamine), each with its own specific demographic and geographic characteristics.
Many public health responses and modeled scenarios for COVID-19 outbreaks caused by SARS-CoV-2 assume that infection results in an immune response that protects individuals from future infections or ...illness for some amount of time. The presence or absence of protective immunity due to infection or vaccination (when available) will affect future transmission and illness severity. Here, we review the scientific literature on antibody immunity to coronaviruses, including SARS-CoV-2 as well as the related SARS-CoV, MERS-CoV and endemic human coronaviruses (HCoVs). We reviewed 2,452 abstracts and identified 491 manuscripts relevant to 5 areas of focus: 1) antibody kinetics, 2) correlates of protection, 3) immunopathogenesis, 4) antigenic diversity and cross-reactivity, and 5) population seroprevalence. While further studies of SARS-CoV-2 are necessary to determine immune responses, evidence from other coronaviruses can provide clues and guide future research.
Mitochondrial DNA (mtDNA) plays a crucial but incompletely understood role in cellular biochemistry and etiology of numerous disease states. Thus, there is an urgent need for targeted probes that can ...dynamically respond to changes to mtDNA such as copy number in live cells, but it is difficult to permeate the mitochondrial membrane of the living cell. Now, a ruthenium(II) light‐switching probe targeted by peptide vectorization selectively to mitochondrial nucleoids is presented. Evidence for DNA binding by the probe in live cells is derived from confocal fluorescence microscopy, resonance Raman, and luminescence lifetime imaging. While viable under imaging conditions, specific staining of mitochondrial DNA permitted efficient and selective photoinduced toxicity on a cell‐by‐cell basis under higher excitation intensities. This powerful combination of imaging and photocytotoxicity is an important step towards realizing phototheranostic application of such RuII probes.
Shining a light on mitochondrial DNA: Peptide vectorization targets a luminescence light‐switching RuII complex to mitochondrial DNA in live cells with high precision. Probe binding was multimodally interrogated by a combination of confocal, Raman, and lifetime imaging. This discrete targeting presents exciting opportunities to exploit the promising phototheranostic capabilities of RuII complexes.
We present the results of a search for transient radio bursts of between 0.125 and 32 ms duration in two archival pulsar surveys of intermediate Galactic latitudes with the Parkes multibeam receiver. ...14 new neutron stars have been discovered, seven of which belong to the recently identified ‘rotating radio transients’ (RRATs) class. Here, we describe our search methodology, and discuss the new detections in terms of how the RRAT population relates to the general population of pulsars. The new detections indicate (1) that the Galactic z-distribution of RRATs in the surveys closely resembles the distribution of pulsars, with objects up to 0.86 kpc from the Galactic plane; (2) where measurable, the RRAT pulse widths are similar to that of individual pulses from pulsars of similar period, implying a similar beaming fraction; and (3) our new detections span a variety of nulling fractions, and thus we postulate that the RRATs may simply be nulling pulsars that are only ‘on’ for less than a pulse period. Finally, the newly discovered object PSR J0941−39 may represent a link between pulsars and RRATs. This bizarre object was discovered as an RRAT, but in follow-up observations often appeared as a bright (∼10 mJy) pulsar with a low nulling fraction. It is obvious therefore that a neutron star can oscillate between being an RRAT and a pulsar. Crucially, the sites of the RRAT pulses are coincident with the pulsar's emission, implying that the two emission mechanisms are linked, and that RRATs are not just pulsars observed from different orientations.
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