Superconductivity is among the most fascinating and well-studied quantum states of matter. Despite over 100 years of research, a detailed understanding of how features of the normal-state electronic ...structure determine superconducting properties has remained elusive. For instance, the ability to deterministically enhance the superconducting transition temperature by design, rather than by serendipity, has been a long sought-after goal in condensed matter physics and materials science, but achieving this objective may require new tools, techniques and approaches. Here, we report the transmutation of a normal metal into a superconductor through the application of epitaxial strain. We demonstrate that synthesizing RuO
thin films on (110)-oriented TiO
substrates enhances the density of states near the Fermi level, which stabilizes superconductivity under strain, and suggests that a promising strategy to create new transition-metal superconductors is to apply judiciously chosen anisotropic strains that redistribute carriers within the low-energy manifold of d orbitals.
Active asteroids are those that show evidence of ongoing mass loss. We report repeated instances of particle ejection from the surface of (101955) Bennu, demonstrating that it is an active asteroid. ...The ejection events were imaged by the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) spacecraft. For the three largest observed events, we estimated the ejected particle velocities and sizes, event times, source regions, and energies. We also determined the trajectories and photometric properties of several gravitationally bound particles that orbited temporarily in the Bennu environment. We consider multiple hypotheses for the mechanisms that lead to particle ejection for the largest events, including rotational disruption, electrostatic lofting, ice sublimation, phyllosilicate dehydration, meteoroid impacts, thermal stress fracturing, and secondary impacts.
We present global hydrodynamic (HD) and magnetohydrodynamic (MHD) simulations with mesh refinement of accreting planets embedded in protoplanetary disks (PPDs). The magnetized disk includes Ohmic ...resistivity that depends on the overlying mass column, leading to turbulent surface layers and a dead zone near the midplane. The main results are; (1) the accretion flow in the Hill sphere is intrinsically three-dimensional for HD and MHD models. Net inflow toward the planet is dominated by high-latitude flows. A circumplanetary disk (CPD) forms. Its midplane flows outward in a pattern whose details differ between models. (2) The opening of a gap magnetically couples and ignites the dead zone near the planet, leading to stochastic accretion, a quasi-turbulent flow in the Hill sphere, and a CPD whose structure displays high levels of variability. (3) Advection of magnetized gas onto the rotating CPD generates helical fields that launch magnetocentrifugally driven outflows. During one specific epoch, a highly collimated, one-sided jet is observed. (4) The CPD's surface density is ~30 g cm super(-2), small enough for significant ionization and turbulence to develop. (5) The accretion rate onto the planet in the MHD simulation reaches a steady value 8 x 10 super(-3) M sub(+ in circle) yr super(-1) and is similar in the viscous HD runs. Our results suggest that gas accretion onto a forming giant planet within a magnetized PPD with a dead zone allows rapid growth from Saturnian to Jovian masses. As well as being relevant for giant planet formation, these results have important implications for the formation of regular satellites around gas giant planets.
LepR3, found in the Brassica napus cv ‘Surpass 400’, provides race-specific resistance to the fungal pathogen Leptosphaeria maculans, which was overcome after great devastation in Australia in 2004. ...We investigated the LepR3 locus to identify the genetic basis of this resistance interaction.
We employed a map-based cloning strategy, exploiting collinearity with the Arabidopsis thaliana and Brassica rapa genomes to enrich the map and locate a candidate gene. We also investigated the interaction of LepR3 with the L. maculans avirulence gene AvrLm1 using transgenics.
LepR3 was found to encode a receptor-like protein (RLP). We also demonstrated that aviru-lence towards LepR3 is conferred by AvrLm1, which is responsible for both the Rlm1 and LepR3-dependent resistance responses in B. napus.
LepR3 is the first functional B. napus disease resistance gene to be cloned. AvrLm1's interaction with two independent resistance loci, Rlm1 and LepR3, highlights the need to consider redundant phenotypes in ‘gene-for-gene’ interactions and offers an explanation as to why LepR3 was overcome so rapidly in parts of Australia.
Characterization of the complex molecular scaffold of the marine polyketide natural product phormidolide A represents a challenge that has persisted for nearly two decades. In light of discordant ...results arising from recent synthetic and biosynthetic reports, a rigorous study of the configuration of phormidolide A was necessary. This report outlines a synergistic effort employing computational and anisotropic NMR investigation, that provided orthogonal confirmation of the reassigned side chain, as well as supporting a further correction of the C7 stereocenter.
A combined computational and anisotropic NMR investigation defined likely configuration of phormidolide.
Non-Euclidean transformations have been recently proposed to produce a link between 3-D homogeneous surfaces and 2-D dielectric lenses. Therefore, the propagation in a geometrical surface has the ...same response of an equivalent refractive index distribution. By using this concept, we propose here a fully metallic Luneburg lens where the propagation is only in the air. Two metallic plates, following a curved shape, are employed to support the propagation mimicking the designed curvature. To reduce the height of the required curvature, the surface has been mirrored twice with respect to two <inline-formula> <tex-math notation="LaTeX">z </tex-math></inline-formula> constant planes. The lens is fed by 11 waveguide ports spaced with an angle of 12.5° providing 1-D beam scanning over an angular range of ±62.5°. A prototype is manufactured and measured with a good agreement with the simulated results between 25 and 36 GHz to demonstrate the concept.
Leukocyte telomere length (LTL) is a proposed marker of biological age. Here we report the measurement and initial characterization of LTL in 474,074 participants in UK Biobank. We confirm that older ...age and male sex associate with shorter LTL, with women on average ~7 years younger in 'biological age' than men. Compared to white Europeans, LTL is markedly longer in African and Chinese ancestries. Older paternal age at birth is associated with longer individual LTL. Higher white cell count is associated with shorter LTL, but proportions of white cell subtypes show weaker associations. Age, ethnicity, sex and white cell count explain ~5.5% of LTL variance. Using paired samples from 1,351 participants taken ~5 years apart, we estimate the within-individual variability in LTL and provide a correction factor for this. This resource provides opportunities to investigate determinants and biomedical consequences of variation in LTL.
•COVID-19 vaccine hesitancy is growing over time.•Vaccinated caregivers, with higher education, worried their child had COVID-19 are most likely to express interest in vaccinating their child.•Having ...a primary care provider but not relying on their advice is associated with not vaccinating children.
To document the level of vaccine hesitancy in caregivers’ of children younger than 12 years of age over the course of the pandemic in Pediatric Emergency Departments (ED).
Study design
Ongoing multicenter, cross-sectional survey of caregivers presenting to 19 pediatric EDs in the USA, Canada, Israel, and Switzerland during first months of the pandemic (phase1), when vaccines were approved for adults (phase2) and most recently when vaccines were approved for children (phase3).
Willingness to vaccinate rate declined over the study period (59.7%, 56.1% and 52.1% in the three phases). Caregivers who are fully vaccinated, who have higher education, and those worried their child had COVID-19 upon arrival to the ED, were more likely to plan to vaccinate in all three phases. Mothers were less likely to vaccinate early in the pandemic, but this hesitancy attenuated in later phases. Older caregivers were more willing to vaccinate, and caregivers of older children were less likely to vaccinate their children in phase 3. During the last phase, willingness to vaccinate was lowest in those who had a primary care provider but did not rely on their advice for medical decisions (34%). Those with no primary care provider and those who do and rely on their medical advice, had similar rates of willingness to vaccinate (55.1% and 52.1%, respectively).
COVID-19 vaccine hesitancy is widespread and growing over time, and public health measures should further try to leverage identified factors associated with hesitancy in order to enhance vaccination rates among children.
Abstract
The evolution of Sr
2
IrO
4
upon carrier doping has been a subject of intense interest, due to its similarities to the parent cuprates, yet the intrinsic behaviour of Sr
2
IrO
4
upon hole ...doping remains enigmatic. Here, we synthesize and investigate hole-doped Sr
2−
x
K
x
IrO
4
utilizing a combination of reactive oxide molecular-beam epitaxy, substitutional diffusion and in-situ angle-resolved photoemission spectroscopy. Upon hole doping, we observe the formation of a coherent, two-band Fermi surface, consisting of both hole pockets centred at (
π
, 0) and electron pockets centred at (
π
/2,
π
/2). In particular, the strong similarities between the Fermi surface topology and quasiparticle band structure of hole- and electron-doped Sr
2
IrO
4
are striking given the different internal structure of doped electrons versus holes.
Understanding what drives breast tumor progression is of utmost importance for blocking tumor metastasis; we have identified that semaphorin 7a is a potent driver of ductal carcinoma in situ (DCIS) ...progression. Semaphorin 7a is a glycophosphatidylinositol membrane-anchored protein that promotes attachment and spreading in multiple cell types. Here, we show that increased expression of SEMA7A occurs in a large percentage of breast cancers and is associated with decreased overall and distant metastasis-free survival. In both in vitro and in vivo models, short hairpin-mediated silencing of SEMA7A reveals roles for semaphorin 7a in the promotion of DCIS growth, motility and invasion as well as lymphangiogenesis in the tumor microenvironment. Our studies also uncover a relationship between COX-2 and semaphorin 7a expression and suggest that semaphorin 7a promotes tumor cell invasion on collagen and lymphangiogenesis via activation of β1-integrin receptor. Our results suggest that semaphorin 7a may be novel target for blocking breast tumor progression.
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