At ambient pressure, CrAs undergoes a first-order transition into a double-helical magnetic state atTN=265K, which is accompanied by a structural transition. The recent discovery of pressure-induced ...superconductivity in CrAs makes it important to clarify the nature of quantum phase transitions out of the coupled structural/helimagnetic order in this system. Here, we show, via neutron diffraction on the single-crystal CrAs under hydrostatic pressure (P), that the combined order is suppressed atPc≈10kbar, near which bulk superconductivity develops with a maximal transition temperatureTc≈2K. We further show that the coupled order is also completely suppressed by phosphorus doping inCrAs1−xPxat a criticalxc≈0.05, above which inelastic neutron scattering evidenced persistent antiferromagnetic correlations, providing a possible link between magnetism and superconductivity. In line with the presence of antiferromagnetic fluctuations nearPc(xc), theAcoefficient of the quadratic temperature dependence of resistivity exhibits a dramatic enhancement asP(x) approachesPc(xc), around whichρ(T)has a non-Fermi-liquid form. Accordingly, the electronic specific-heat coefficient ofCrAs1−xPxpeaks aroundxc. These properties provide clear evidence for quantum criticality, which we interpret as originating from a nearly second-order helimagnetic quantum phase transition that is concomitant with a first-order structural transition. Our findings in CrAs highlight the distinct characteristics of quantum criticality in bad metals, thereby bringing out new insights into the physics of unconventional superconductivity such as those occurring in the high-Tciron pnictides.
Embolic strokes of undetermined source represent 20% of ischemic strokes and are associated with a high rate of recurrence. Anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, may ...result in a lower risk of recurrent stroke than aspirin.
We compared the efficacy and safety of rivaroxaban (at a daily dose of 15 mg) with aspirin (at a daily dose of 100 mg) for the prevention of recurrent stroke in patients with recent ischemic stroke that was presumed to be from cerebral embolism but without arterial stenosis, lacune, or an identified cardioembolic source. The primary efficacy outcome was the first recurrence of ischemic or hemorrhagic stroke or systemic embolism in a time-to-event analysis; the primary safety outcome was the rate of major bleeding.
A total of 7213 participants were enrolled at 459 sites; 3609 patients were randomly assigned to receive rivaroxaban and 3604 to receive aspirin. Patients had been followed for a median of 11 months when the trial was terminated early because of a lack of benefit with regard to stroke risk and because of bleeding associated with rivaroxaban. The primary efficacy outcome occurred in 172 patients in the rivaroxaban group (annualized rate, 5.1%) and in 160 in the aspirin group (annualized rate, 4.8%) (hazard ratio, 1.07; 95% confidence interval CI, 0.87 to 1.33; P=0.52). Recurrent ischemic stroke occurred in 158 patients in the rivaroxaban group (annualized rate, 4.7%) and in 156 in the aspirin group (annualized rate, 4.7%). Major bleeding occurred in 62 patients in the rivaroxaban group (annualized rate, 1.8%) and in 23 in the aspirin group (annualized rate, 0.7%) (hazard ratio, 2.72; 95% CI, 1.68 to 4.39; P<0.001).
Rivaroxaban was not superior to aspirin with regard to the prevention of recurrent stroke after an initial embolic stroke of undetermined source and was associated with a higher risk of bleeding. (Funded by Bayer and Janssen Research and Development; NAVIGATE ESUS ClinicalTrials.gov number, NCT02313909 .).
Strain gradient polarization in graphene Kundalwal, S.I.; Meguid, S.A.; Weng, G.J.
Carbon (New York),
June 2017, 2017-06-00, 20170601, Volume:
117
Journal Article
Peer reviewed
Flexoelectricity phenomenon is the response of electric polarization to an applied strain gradient and is developed as a consequence of crystal symmetry in all materials. In this study, we show that ...the presence of strain gradient in non-piezoelectric graphene sheet does not only affect the ionic positions, but also the asymmetric redistribution of the electron density, which induce strong polarization in the graphene sheet. Using quantum mechanics calculations, the resulting axial and normal piezoelectric coefficients of the graphene sheet were determined using two loading conditions: (i) a graphene sheet containing non-centrosymmetric pores subjected to an axial load, and (ii) a pristine graphene sheet subjected to a bending moment. Particular emphases were placed on the role of edge and corner states of pores arising due to the functionalization. We also investigated the electronic structure of graphene sheet under different in-plane strain distributions using quantum mechanics calculations and tight-binding approach. The findings of our work reveal that the respective axial and normal electromechanical couplings in graphene can be engineered by changing the size of non-centrosymmetric pores and radii of curvature. Our fundamental study highlights the possibility of using graphene sheets in nanoelectromechanical systems as sensors or actuators.
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Banana is the most popular and most exported fruit and also a major food crop for millions of people around the world. Despite its importance and the presence of serious disease threats, research ...into this crop is limited. One of those is Panama disease or Fusarium wilt. In the previous century Fusarium wilt wiped out the "Gros Michel" based banana industry in Central America. The epidemic was eventually quenched by planting "Cavendish" bananas. However, 50 years ago the disease recurred, but now on "Cavendish" bananas. Since then the disease has spread across South-East Asia, to the Middle-East and the Indian subcontinent and leaped into Africa. Here, we report the presence of
f.sp.
Tropical Race 4 (Foc TR4) in "Cavendish" plantations in Laos, Myanmar, and Vietnam. A combination of classical morphology, DNA sequencing, and phenotyping assays revealed a very close relationship between the Foc TR4 strains in the entire Greater Mekong Subregion (GMS), which is increasingly prone to intensive banana production. Analyses of single-nucleotide polymorphisms enabled us to initiate a phylogeography of Foc TR4 across three geographical areas-GMS, Indian subcontinent, and the Middle East revealing three distinct Foc TR4 sub-lineages. Collectively, our data place these new incursions in a broader agroecological context and underscore the need for awareness campaigns and the implementation of validated quarantine measures to prevent further international dissemination of Foc TR4.
Conceptual and theoretical links between politics and public health are longstanding. Internationally comparative systematic review evidence has shown links between four key political exposures - the ...welfare state, political tradition, democracy and globalisation - on population health outcomes. However, the pathways through which these influences may operate have not been systematically appraised. Therefore, focusing on child and maternal health outcomes, we present a realist re-analysis of the dataset from a recent systematic review.
The database from a recent systematic review on the political determinants of health was used as the data source for this realist review. Included studies from the systematic review were re-evaluated and those relating to child and/or maternal health outcomes were included in the realist synthesis. Initial programme theories were generated through realist engagement with the prior systematic review. These programme theories were adjudicated and refined through detailed engagement with the evidence base using a realist re-synthesis involving two independent reviewers. The revised theories that best corresponded to the evidence base formed the final programme theories.
Out of the 176 included studies from the systematic review, a total of 67 included child and/or maternal health outcomes and were included in the realist re-analysis. Sixty-three of these studies were ecological and data were collected between 1950 and 2014. Six initial programme theories were generated. Following theory adjudication, three theories in revised form were supported and formed the final programme theories. These related to a more generous welfare state leading to better child and maternal health especially in developed countries through progressive social welfare policies, left-of-centre political tradition leading to lower child mortality and low birth weight especially in developed countries through greater focus on welfare measures, and increased globalisation leading to greater child and infant mortality and youth smoking rates in LMECs through greater influence of multinational corporations and neoliberal trade organisations.
We present a realist re-analysis of a large systematically identified body of evidence on how four key political exposures - the welfare state, democracy, political tradition and globalisation - relate to child and maternal health outcomes. Three final programme theories were supported.
We report the superconductivity of PbTaS2 single crystals with the centrosymmetric structure. The systematic measurements of magnetization, electric transport and specific heat indicate that PbTaS2 ...is a weakly coupled type-II superconductor with transition temperature T c ∼ 2.6 K. Furthermore, the band structure calculations predicted four nodal lines near the Fermi energy with “drumhead-like” surface states, suggesting centrosymmetric PbTaS2 is a candidate of topological nodal line semimetals. These results demonstrate that PbTaS2 may open up another avenue for further exploring the properties of superconductivity and topological nodal-line states.
Kidney stones is one of the common diseases of the urinary system. The primary cause of kidney stone formation is the thermodynamic supersaturation of lithogenic solutes in urine, which desaturates ...by nucleation, crystal growth and aggregation of minerals and salts, mainly Calcium oxalate (CaOx). One of the potential therapies is to develop drug molecules to inhibit or prevent CaOx crystallization in urine. Traditional Chinese medicines (TCMs) provided an efficient approach for the treatment of kidney stones with a specialized-designed recipe of medicinal herbs. But the action details of these herbs were poorly understood due to their complex components, and whether the effective constituents of herbs have an inhibitory effect on the process of stone formation has not been evaluated.
This study aims to develop and identify inhibitor substitutes from a library of kidney stone prescriptions in traditional Chinese medicines to prevent pathological kidney stone formation.
As many as twenty Chinese medicines were extracted and separated into five different polar extracts, the inhibition performance of which on CaOx crystallization was explored by recording and comparing crystallization kinetics. The potential inhibitor molecules in the inhibitory extracts were confirmed by HPLC and their retardation efficacy was evaluated by quantifying nucleation and growth kinetics using colorimetry. Then the inhibitor-COM crystal interactions and specificity were examined by morphology evolution and surface structure analysis. In vitro inhibition performance of inhibitors on crystal growth and attachment of CaOx crystals to human renal epithelial cells were further evaluated by recording the nucleation and adhesive crystal numbers.
Water- and n-butanol- soluble extracts from 20 kinds of herbs show almost 100% inhibition percentage, and the n-butanol extracts was found better than commercial drug citrate. Twenty-one molecule substitutes were identified from these extracts, and among them polyphenols display the best inhibition efficacy to retard CaOx crystallization. The high-throughput colorimetric assay and morphology examinations reveals thirteen out of 21 molecules show inhibition potential and disrupt growth of CaOx monohydrate crystals by interacting with exposed Ca2+ and C2O42− on the (100) and (010) surfaces. Moreover, these inhibitors also display pronounced performance in protecting renal epithelial cells by inhibiting nucleation and adhesion of CaOx crystals to cells, thus reducing stone formation. The structure-performance correlation among 19 screened molecules that inhibitors having pKa<3.5, logD (pH = 6) <0, H-number>0.1 mmol are the best in suppressing CaOx crystallization. Our findings provide a novel solution to design and manufacture inhibitor drugs from Chinese medicines for preventing pathological kidney stones formation.
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•Discovering inhibitor substitutes for CaOx stones crystallization from traditional Chinese medicines.•Water and n-butanol soluble extracts from 20 Chinese medicines are the most efficient inhibitors for CaOx crystallization.•Phenolic compounds in these extracts were discovered to inhibit dramatically CaOx crystallization.•Anti-adhesive ability of these inhibitors indicates the pronounced efficacy on reduction of stones formation.•Structure-performance relationship of substitutes shows pKa and H-number of inhibitors determining the inhibition efficacy.
Child and maternal health, a key marker of overall health system performance, is a policy priority area by the World Health Organization and the United Nations, including the Sustainable Development ...Goals. Previous realist work has linked child and maternal health outcomes to globalization, political tradition, and the welfare state. It is important to explore the role of other key policy-related factors. This paper presents a realist synthesis, categorising policy instruments according to the established NATO model, to develop an explanatory model of how policy instruments impact child and maternal health outcomes.
A systematic literature search was conducted to identify studies assessing the relationships between policy instruments and child and maternal health outcomes. Data were analysed using a realist framework. The first stage of the realist analysis process was to generate micro-theoretical initial programme theories for use in the theory adjudication process. Proposed theories were then adjudicated iteratively to produce a set of final programme theories.
From a total of 43,415 unique records, 632 records proceeded to full-text screening and 138 papers were included in the review. Evidence from 132 studies was available to address this research question. Studies were published from 1995 to 2021; 76% assessed a single country, and 81% analysed data at the ecological level. Eighty-eight initial candidate programme theories were generated. Following theory adjudication, five final programme theories were supported. According to the NATO model, these were related to treasure, organisation, authority-treasure, and treasure-organisation instrument types.
This paper presents a realist synthesis to develop an explanatory model of how policy instruments impact child and maternal health outcomes from a large, systematically identified international body of evidence. Five final programme theories were supported, showing how policy instruments play an important yet context-dependent role in influencing child and maternal health outcomes.
•Mg–Zn–Ca metallic glass powders were synthesized by gas-atomization.•The phase structure of powders was affected by the composition and the size.•Degradation capacity of powders is determined by ...phase constituents and Mg content.•Nano-whiskers are distributed loosely on the reacted surface of the glassy powder.
Mg–Zn–Ca powders of Mg63+xZn32−xCa5 (x=0, 3, 7 and 10) with the diameter from 2μm to 180μm were synthesized by gas-atomization. The relationship among powder morphology, the composition, glass forming ability, thermal stability, corrosion resistance and the capacity in degrading azo dyes for these powders was investigated. It is shown that fully glass powders with the particle diameter<150μm can be atomized for alloys with x≤7. These Mg–Zn–Ca metallic glass powders exhibit remarkably superior corrosion resistance and degradation capacity in Direct Blue 6 solution to their crystalline counterparts and Fe powders. Nano-whiskers were formed uniformly and loosely on the reacted surface of the Mg70Zn25Ca5 glassy powder, which is considered as the mechanism of high degrading capacity for these Mg–Zn–Ca glassy alloys. This work will contribute to the development of massive production of high quality metallic glass powders with excellent capability in degrading azo dyes.
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