Current methods of chemical vapour deposition (CVD) of graphene on copper are complicated by multiple processing steps and by high temperatures required in both preparing the copper and inducing ...subsequent film growth. Here we demonstrate a plasma-enhanced CVD chemistry that enables the entire process to take place in a single step, at reduced temperatures (<420 °C), and in a matter of minutes. Growth on copper foils is found to nucleate from arrays of well-aligned domains, and the ensuing films possess sub-nanometre smoothness, excellent crystalline quality, low strain, few defects and room-temperature electrical mobility up to (6.0±1.0) × 10(4) cm(2) V(-1) s(-1), better than that of large, single-crystalline graphene derived from thermal CVD growth. These results indicate that elevated temperatures and crystalline substrates are not necessary for synthesizing high-quality graphene.
Summary
The receptor activator of nuclear factor-kappa B ligand (RANKL)/RANK/osteoprotegerin system is dysregulated in hyperparathyroid bone diseases. The introduction of denosumab preceding elective ...surgery as an alternative option when surgery is not possible immediately.
Introduction
The effects of denosumab on vascular calcification in patients with chronic renal failure and low bone mass have been a subject of interest. Therefore, this investigation aimed to determine the short-term changes in vascular calcification after denosumab treatment using a serial electrocardiography-gated computed tomography (CT) to measure coronary artery calcification (CAC) in patients with secondary hyperparathyroidism (SHPT) and low bone mass.
Methods
This 6-month study enrolled patients with SHPT and low bone mass (T-score < − 2.5) owing to dialysis. The 2 groups administered denosumab at a dose of 60 mg (denosumab group), and conventional treatment (control group) had 21 patients each. All patients underwent CT scans at baseline and at the follow-up examination at 6 months to determine the bone mineral density and CAC.
Results
The control group demonstrated a significant increase in Agatston scores (187.79 ± 72.27) (
P
= 0.004). However, no significant change was noted in the denosumab group (
P
= 0.41). In the denosumab group, only the baseline serum alkaline phosphatase levels correlated negatively with changes in the CAC score (
P =
0.01); the baseline alkaline phosphatase levels were the deciding biomarkers for non-responsive CAC scores by Berry Criteria after denosumab treatment (
P
= 0.02). The denosumab group demonstrated significantly increased bone mineral density in the femoral neck and lumbar spine (
P
< 0.01).
Conclusion
The findings provide evidence that denosumab may suppress the progression of CAC and also regress osseous calcification in severe cases of high bone turnover.
Spitzer data at 24, 70, and 160 {mu}m and ground-based H{alpha} images are analyzed for a sample of 189 nearby star-forming and starburst galaxies to investigate whether reliable star formation rate ...(SFR) indicators can be defined using the monochromatic infrared dust emission centered at 70 and 160 {mu}m. We compare recently published recipes for SFR measures using combinations of the 24 {mu}m and observed H{alpha} luminosities with those using 24 {mu}m luminosity alone. From these comparisons, we derive a reference SFR indicator for use in our analysis. Linear correlations between SFR and the 70 {mu}m and 160 {mu}m luminosity are found for L(70) {approx_gt} 1.4 x 10{sup 42} erg s{sup -1} and L(160) {approx_gt} 2 x 10{sup 42} erg s{sup -1}, corresponding to SFR {approx_gt} 0.1-0.3 M{sub sun} yr{sup -1}, and calibrations of SFRs based on L(70) and L(160) are proposed. Below those two luminosity limits, the relation between SFR and 70 {mu}m (160 {mu}m) luminosity is nonlinear and SFR calibrations become problematic. A more important limitation is the dispersion of the data around the mean trend, which increases for increasing wavelength. The scatter of the 70 {mu}m (160 {mu}m) data around the mean is about 25% (factor {approx}2) larger than the scatter of the 24 {mu}m data. We interpret this increasing dispersion as an effect of the increasing contribution to the infrared emission of dust heated by stellar populations not associated with the current star formation. Thus, the 70 (160) {mu}m luminosity can be reliably used to trace SFRs in large galaxy samples, but will be of limited utility for individual objects, with the exception of infrared-dominated galaxies. The nonlinear relation between SFR and the 70 and 160 {mu}m emission at faint galaxy luminosities suggests a variety of mechanisms affecting the infrared emission for decreasing luminosity, such as increasing transparency of the interstellar medium, decreasing effective dust temperature, and decreasing filling factor of star-forming regions across the galaxy. In all cases, the calibrations hold for galaxies with oxygen abundance higher than roughly 12 +log(O/H) {approx} 8.1. At lower metallicity, the infrared luminosity no longer reliably traces the SFR because galaxies are less dusty and more transparent.
MicroRNAs (miRNAs) play important roles in tumorigenesis by regulating oncogenes and tumor-suppressor genes. In this study, miR-187 and miR-200a were found to be expressed at higher levels in ovarian ...cancers than in benign tumors. In patients with ovarian cancer, however, higher levels of miR-187 and miR-200a expression were paradoxically associated with better OS and recurrence-free survival. Further, multivariate analysis showed that miR-187 served as an independent prognostic factor for patients with ovarian cancer (n=176). Computational prediction and microarray results indicated that miR-187 directly targeted Disabled homolog-2 (Dab2), and luciferase reporter assays confirmed that the target site of miR-187 was located at the 3'-UTR of the Dab2 gene. Generally considered as a tumor-suppressor gene, Dab2 may actually promote tumor progression in advanced cancers through epithelial-to-mesenchymal transition (EMT). Ectopic expression of miR-187 in cancer cells promoted cell proliferation, but continued overexpression of miR-187 suppressed Dab2 and inhibited migration. Suppression of miR-187 upregulated Dab2, which, by inhibiting E-cadherin levels while stimulating vimentin and phospho-FAK levels, promoted EMT. Reduced ovarian cancer Dab2 histoscores correlated with high miR-187 levels and improved outcomes of patients. Collectively, these results demonstrate distinct dual roles of Dab2 in cell proliferation and tumor progression. In the initial steps of tumorigenesis, upregulated miR-187 suppresses Dab2, promoting cell proliferation. During the later stages, however, continued increased levels of miR-187 inhibits the Dab2-dependent EMT that is associated with tumor invasiveness, which is presumed to be the reason why cancers with high miR-187 levels were associated with better survivals.
•A twinning and de-twinning model (TDT) is proposed to describe crystal plasticity.•Four mechanisms include nucleation, growth, shrinkage and re-twinning of twins.•Growth and shrinkage of twins are ...related with both matrix and twin domains.•TDT model can capture the key phenomena observed in experiments.
Together with slip, deformation twinning and de-twinning are the plastic deformation mechanisms in hexagonal close packed (HCP) crystals, which strongly affect texture evolution and anisotropic response. As a consequence, several twinning models have been proposed and implemented in the existing polycrystalline plasticity models. De-twinning is an inverse process with respect to twinning, which is relevant to cycling, fatigue and complex loads but is rarely incorporated into polycrystalline plastic models. In this paper, we propose a physics-based twinning and de-twinning (TDT) model that has the capability of dealing with both mechanisms during plastic deformation. The TDT model is characterized by four deformation mechanisms corresponding to twin nucleation, twin growth, twin shrinkage and re-twinning. Twin nucleation and twin growth are associated with deformation twinning, and twin shrinkage and re-twinning are associated with de-twinning. The proposed TDT model is implemented in the Elasto-Visco-Plastic Self-Consistent (EVPSC) model. We demonstrate the validity and the capability of the TDT model by simulating cyclic loading of magnesium alloys AZ31B plate and AZ31 bar. Comparison with the measurements indicates that the TDT model is able to capture the key features observed in experiments, implying that the mechanical response in the simulated materials is mainly associated with twinning and de-twinning.
The fundamental building blocks of the proton-quarks and gluons-have been known for decades. However, we still have an incomplete theoretical and experimental understanding of how these particles and ...their dynamics give rise to the quantum bound state of the proton and its physical properties, such as its spin
. The two up quarks and the single down quark that comprise the proton in the simplest picture account only for a few per cent of the proton mass, the bulk of which is in the form of quark kinetic and potential energy and gluon energy from the strong force
. An essential feature of this force, as described by quantum chromodynamics, is its ability to create matter-antimatter quark pairs inside the proton that exist only for a very short time. Their fleeting existence makes the antimatter quarks within protons difficult to study, but their existence is discernible in reactions in which a matter-antimatter quark pair annihilates. In this picture of quark-antiquark creation by the strong force, the probability distributions as a function of momentum for the presence of up and down antimatter quarks should be nearly identical, given that their masses are very similar and small compared to the mass of the proton
. Here we provide evidence from muon pair production measurements that these distributions are considerably different, with more abundant down antimatter quarks than up antimatter quarks over a wide range of momenta. These results are expected to revive interest in several proposed mechanisms for the origin of this antimatter asymmetry in the proton that had been disfavoured by previous results
, and point to future measurements that can distinguish between these mechanisms.
Thulium iron garnet (TmIG) films with perpendicular magnetic anisotropy (PMA) were grown on gadolinium gallium garnet (GGG) (111) substrates by off-axis sputtering. High-resolution synchrotron ...radiation X-ray diffraction studies and spherical aberration-corrected scanning transmission electron microscope (Cs-corrected STEM) images showed the excellent crystallinity of the films and their sharp interface with GGG. Damping constant of TmIG thin film was determined to be 0.0133 by frequency-dependent ferromagnetic resonance (FMR) measurements. The saturation magnetization (M
) and the coercive field (H
) were obtained systematically as a function of the longitudinal distance (L) between the sputtering target and the substrate. A 170% enhancement of PMA field (H
) was achieved by tuning the film composition to increase the tensile strain. Moreover, current-induced magnetization switching on a Pt/TmIG structure was demonstrated with an ultra-low critical current density (j
) of 2.5 × 10
A/cm
, an order of magnitude smaller than the previously reported value. We were able to tune M
, H
and H
to obtain an ultra-low j
of switching the magnetization, showing the great potential of sputtered TmIG films for spintronics.
Combining transmission electron microscopes and density functional theory calculations, we report the nucleation and growth mechanisms of room temperature rolling induced face-centered cubic titanium ...(fcc-Ti) in polycrystalline hexagonal close packed titanium (hcp-Ti). Fcc-Ti and hcp-Ti take the orientation relation: 〈0001〉hcp||〈001〉fcc and , different from the conventional one. The nucleation of fcc-Ti is accomplished via pure-shuffle mechanism with a minimum stable thickness of three atomic layers, and the growth via shear-shuffle mechanisms through gliding two-layer disconnections or pure-shuffle mechanisms through gliding four-layer disconnections. Such phase transformation offers an additional plastic deformation mode comparable to twinning.
We report a hafnium-containing MOF, hcp UiO-67(Hf), which is a ligand-deficient layered analogue of the face-centered cubic fcu UiO-67(Hf). hcp UiO-67 accommodates its lower ligand:metal ratio ...compared to fcu UiO-67 through a new structural mechanism: the formation of a condensed “double cluster” (Hf12O8(OH)14), analogous to the condensation of coordination polyhedra in oxide frameworks. In oxide frameworks, variable stoichiometry can lead to more complex defect structures, e.g., crystallographic shear planes or modules with differing compositions, which can be the source of further chemical reactivity; likewise, the layered hcp UiO-67 can react further to reversibly form a two-dimensional metal–organic framework, hxl UiO-67. Both three-dimensional hcp UiO-67 and two-dimensional hxl UiO-67 can be delaminated to form metal–organic nanosheets. Delamination of hcp UiO-67 occurs through the cleavage of strong hafnium-carboxylate bonds and is effected under mild conditions, suggesting that defect-ordered MOFs could be a productive route to porous two-dimensional materials.
A new constitutive model to describe twinning and detwinning for polycrystalline materials with the hexagonal close packed (HCP) crystallographic structure is developed and implemented in the ...recently developed elastic viscoplastic self-consistent (EVPSC) polycrystal model. The new model is then applied to magnesium alloy Mg–3 Al–1 Zn (AZ31B) sheet under cyclic loadings and strain path changes. It is demonstrated that the new twinning model is able to capture key features associated with twinning and detwinning observed experimentally.
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