The formability and mechanical properties of many engineering alloys are intimately related to the formation and growth of twins. Understanding the structure and chemistry of twin boundaries at the ...atomic scale is crucial if we are to properly tailor twins to achieve a new range of desired properties. We report an unusual phenomenon in magnesium alloys that until now was thought unlikely: the equilibrium segregation of solute atoms into patterns within fully coherent terraces of deformation twin boundaries. This ordered segregation provides a pinning effect for twin boundaries, leading to a concomitant but unusual situation in which annealing strengthens rather than weakens these alloys. The findings point to a platform for engineering nano-twinned structures through solute atoms. This may lead to new alloy compositions and thermomechanical processes.
A computationally efficient quantitative virtual front tracking model for the two-dimensional simulation of dendritic growth in the low Péclet number regime is developed. The kinetics of dendritic ...growth is driven by the difference between the local equilibrium composition, calculated from the local temperature and curvature, and the local actual liquid composition, obtained by solving the solutal transport equation. The dynamics of dendrite growth from the initial unstable stage to the steady-state stage is accurately described. Side branching develops without the need to introduce local noise. The model adopts the previously proposed solutions for the evaluation of local curvature and interface capturing rules with a virtual interface tracking scheme, which make the model virtually mesh-independent. To decrease the computational time, dendrite growth is calculated directly from fraction solid, eliminating the need to first calculate the growth velocity. Extensive model analysis and validation are presented.
Summary
Sarcopenia was reported to be significantly associated with osteoporosis. In this study, we reported for the first time that sarcopenia was an independent risk predictor of osteoporotic ...vertebral compression refractures (OVCRFs). Other risk factors of OVCRFs are low bone mass density T-scores, female sex, and advanced age.
Introduction
The purpose of this study was to investigate the association between osteoporotic vertebral compression refractures (OVCRFs) and sarcopenia, and to identify other risk factors of OVCRFs.
Methods
We evaluated 237 patients with osteoporotic vertebral compression fracture who underwent percutaneous kyphoplasty (PKP) in our hospital from August 2016 to December 2017. To diagnose sarcopenia, a cross-sectional computed tomography (CT) image at the inferior aspect of the third lumbar vertebra (L3) was selected for estimating muscle mass. Grip strength was used to assess muscle strength. Possible risk factors, such as age, sex, body mass index (BMI), bone mineral density (BMD), location of the treated vertebra, anterior-posterior ratio (AP ratio) of the fractured vertebra, cement leakage, and vacuum clefts, were assessed. The multivariable analysis was used to determine the risk factors of OVCRFs.
Results
During the follow-up period, OVCRFs occurred in 64 (27.0%) patients. Sarcopenia was present in 48 patients (20.3%), including 21 OVCRFs and 27 non-OVCRFs patients. Sarcopenia was significantly correlated with advanced age, lower BMI, lower BMD, and hypoalbuminemia. Compared with non-sarcopenic patients, sarcopenic patients had higher OVCRFs risk. In univariate analysis, sarcopenia (
p
= 0.003), female (
p
= 0.024), advanced age (≥ 75 years;
p
< 0.001), lower BMD (
p
< 0.001), lower BMI (
p
= 0.01), TL junction (vertebral levels at the thoracolumbar junction) (
p
= 0.01), cardiopulmonary comorbidity (
p
= 0.042), and hypoalbuminemia (
p
= 0.003) were associated with OVCRFs. Multivariable analysis revealed that sarcopenia (OR 2.271; 95% CI 1.069–4.824,
p
= 0.033), lower BMD (OR 1.968; 95% CI 1.350–2.868,
p
< 0.001), advanced age (≥ 75 years; OR 2.431; 95% CI 1.246–4.744,
p
= 0.009), and female sex (OR 4.666; 95% CI 1.400–15.552,
p
= 0.012) were independent risk predictors of OVCRFs.
Conclusions
Sarcopenia is an independent risk predictor of osteoporotic vertebral compression refractures. Other factors affecting OVCRFs are low BMD T-scores, female sex, and advanced age.
Graphene-based Josephson junctions provide a novel platform for studying the proximity effect1, 2, 3 due to graphene's unique electronic spectrum and the possibility to tune junction properties by ...gate voltage4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16. Here we describe graphene junctions with a mean free path of several micrometres, low contact resistance and large supercurrents. Such devices exhibit pronounced Fabry-Pérot oscillations not only in the normal-state resistance but also in the critical current. The proximity effect is mostly suppressed in magnetic fields below 10 mT, showing the conventional Fraunhofer pattern. Unexpectedly, some proximity survives even in fields higher than 1 T. Superconducting states randomly appear and disappear as a function of field and carrier concentration, and each of them exhibits a supercurrent carrying capacity close to the universal quantum limit17, 18. We attribute the high-field Josephson effect to mesoscopic Andreev states that persist near graphene edges. Our work reveals new proximity regimes that can be controlled by quantum confinement and cyclotron motion.
► ET were measured for three years using EC and LAS at three sites over a basin. ► The seasonal and interannual variations of observed ET at two scales were analyzed. ► ET differences among the years ...and sites, from EC and LAS measurements were analyzed. ► ET measurements were compared to field water balance calculations and MODIS products.
Evapotranspiration (ET) observations were made for 3years (2008–2010), using eddy covariance (EC) systems and large aperture scintillometers (LAS), in typical underlying surfaces across the Hai River Basin: orchards (Miyun, MY), cropland in the suburbs (Daxing, DX), and cropland in the plains (Guantao, GT). Reliable data were obtained after carefully data processing, and the seasonal and interannual variability in ET was quantitatively analyzed. The annual ET during 2008–2010 ranged from 510–730mm for the EC measurements and 430–560mm for the LAS measurements. The differences in ET among the years and sites were connected with differences in soil moisture and crop growing conditions. The difference in the source areas of EC and LAS measurements and the heterogeneity in their source areas are the primary causes of the discrepancy between EC and LAS measurements. The EC and LAS measurements are compared to the field water balance method calculation and MOD16 ET (the MODIS ET product from the MODIS Global Evapotranspiration Project), respectively. The average difference was 0.85% (mean relative error) and 33.80mm (root mean square error) between the EC measurements and field water balance method calculations, and 7.72% and 47.08mm between LAS measurements and MOD16 ET from 2008 to 2010 at the three sites. We found a decreasing tendency for ET in the past 15years across the Hai River Basin, especially after the year of 2005.
Hydrolysis of sodium borohydride (NaBH sub(4)) is one of the most attractive methods for energy generation of mobile systems used as hydrogen source because of the high gravimetric density and ...controllable hydrogen generation of NaBH sub(4). However, regeneration of NaBH sub(4) is a key issue that remains to be solved, and the energy efficiency of NaBH sub(4) is unknown. In the present study, the energy efficiency of NaBH sub(4) hydrolysis and the entire process of sodium metaborate (NaBO sub(2)) regeneration via reaction with magnesium hydride (MgH sub(2)) is determined through thermodynamics calculations. The maximum energy efficiency is 49.91%, indicating that NaBH sub(4) generation by reaction between MgH sub(2) and NaBO sub(2) during ball milling is feasible. An inexpensive high-energy ball milling method is employed to regenerate NaBH sub(4) by reaction of NaBO sub(2) with magnesium-lanthanum hydrides (H-Mg sub(3)La). Products after ball milling are characterized through Fourier transform infrared spectroscopy and X-ray diffraction measurements. In the reaction of NaBO sub(2) with H-Mg sub(3)La, MgH sub(2) reacts with NaBO sub(2) and then lanthanum hydride (LaH sub(3)) reacts with NaBO sub(2) to produce NaBH sub(4).
Development of brown-like/beige adipocytes in white adipose tissue (WAT) helps to reduce obesity. Thus we investigated the effects of resveratrol, a dietary polyphenol capable of preventing obesity ...and related complications in humans and animal models, on brown-like adipocyte formation in inguinal WAT (iWAT).
CD1 female mice (5-month old) were fed a high-fat diet with/without 0.1% resveratrol. In addition, primary stromal vascular cells separated from iWAT were subjected to resveratrol treatment. Markers of brown-like (beige) adipogenesis were measured and the involvement of AMP-activated protein kinase (AMPK) α1 was assessed using conditional knockout.
Resveratrol significantly increased mRNA and/or protein expression of brown adipocyte markers, including uncoupling protein 1 (UCP1), PR domain-containing 16, cell death-inducing DFFA-like effector A, elongation of very long-chain fatty acids protein 3, peroxisome proliferator-activated receptor-γ coactivator 1α, cytochrome c and pyruvate dehydrogenase, in differentiated iWAT stromal vascular cells (SVCs), suggesting that resveratrol induced brown-like adipocyte formation in vitro. Concomitantly, resveratrol markedly enhanced AMPKα1 phosphorylation and differentiated SVC oxygen consumption. Such changes were absent in cells lacking AMPKα1, showing that AMPKα1 is a critical mediator of resveratrol action. Resveratrol also induced beige adipogenesis in vivo along with the appearance of multiocular adipocytes, increased UCP1 expression and enhanced fatty acid oxidation.
Resveratrol induces brown-like adipocyte formation in iWAT via AMPKα1 activation and suggest that its beneficial antiobesity effects may be partly due to the browning of WAT and, as a consequence, increased oxygen consumption.
Solving linear systems of equations is ubiquitous in all areas of science and engineering. With rapidly growing data sets, such a task can be intractable for classical computers, as the best known ...classical algorithms require a time proportional to the number of variables N. A recently proposed quantum algorithm shows that quantum computers could solve linear systems in a time scale of order log(N), giving an exponential speedup over classical computers. Here we realize the simplest instance of this algorithm, solving 2×2 linear equations for various input vectors on a quantum computer. We use four quantum bits and four controlled logic gates to implement every subroutine required, demonstrating the working principle of this algorithm.
Mg-based materials are promising candidates for high capacity hydrogen storage. However, their poor hydrogenation/dehydrogenation kinetics and high desorption temperature are the main obstacles to ...their applications. This paper reports a method for in situ formation of cycle stable CeH2.73-MgH2-Ni nanocomposites, from the hydrogenation of as-melt Mg80Ce18Ni2 alloy, with excellent hydrogen storage performance. The nanocomposites demonstrate reversible hydrogen storage capacity of more than 4.0 wt %, at a low desorption temperature with fast kinetics and long cycle life. The temperature for the full hydrogenation/dehydrogenation cycle of the composites is significantly decreased to 505 K, which is about 100 K lower than that for pure Mg. The hydrogen desorption activation energy is 63 ± 3 kJ/mol H2 for the composites, which is significantly lower than those of Mg3Ce alloy and pure Mg (104 ± 7 and 158 ± 2 kJ/mol H2, respectively). X-ray diffraction and transmission electron microscopy have been used to reveal the mechanism that delivers this excellent cycle stability and fast hydriding/dehydriding kinetics. It is found that the hydriding/dehydriding process is catalyzed by the combination of in situ formed extremely fine CeH2/CeH2.73 and Ni to Mg/MgH2. In addition, this nanocomposite structure can effectively suppress Mg/MgH2 grain growth and enable the material to maintain its high performance for more than 500 hydrogenation dehydrogenation cycles.
The 18R and 14H long-period stacking ordered structures formed in Mg–Y–Zn alloys are examined systematically using electron diffraction and high-angle annular dark-field scanning transmission ...electron microscopy. In contrast to that reported in previous studies, the 18R structure is demonstrated to have an
ordered base-centred monoclinic lattice, with Y and Zn atoms having an
ordered arrangement in the closely packed planes. Furthermore, the composition of 18R is suggested to be Mg
10Y
1Zn
1, instead of the Mg
12Y
1Zn
1 composition that is commonly accepted. The 14H structure is also
ordered. It has a hexagonal unit cell; the
ordered distribution of Y and Zn atoms in the unit cell is similar to that in the 18R and its composition is Mg
12Y
1Zn
1. The 18R unit cell has three ABCA-type building blocks arranged in the same shear direction, while the 14H unit cell has two ABCA-type building blocks arranged in opposite shear directions.
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