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The transition metal compound catalysts have been taken a great part in renewable energy conversion and storage systems. Herein, we report the uniform CoFe2O4 nanoparticles with abundant oxygen vacancies and specific active surface exposed through the simple hydrothermal reaction for improving the electrocatalytic performance and stability. They show good electrocatalytic performance for hydrogen evolution reaction in 0.5 M H2SO4 with an onset potential of 20 mV, the overpotential of 45 mV (at j = 10 mA/cm2), and remarkable long-term stability more than 100 h at different current densities and better oxygen reduction reaction activity with lower overpotential in 0.1 M KOH. Moreover, the home-made primary Zn–air batteries, using CoFe2O4 nanoparticles as an air–cathode display the high open-circuit voltage of 1.47 V and the maximum power density of 142 mW/cm2. The two-series-connected batteries fabricated by CoFe2O4 nanoparticles can support a light-emitting diode to work for more than 48 h.
We propose a hybrid spectral element method for fractional two-point boundary value problem (FBVPs) involving both Caputo and Riemann-Liouville (RL) fractional derivatives. We first formulate these FBVPs as a second kind Volterra integral equation (VIEs) with weakly singular kernel, following a similar procedure in . We then design a hybrid spectral element method with generalized Jacobi functions and Legendre polynomials as basis functions. The use of generalized Jacobi functions allow us to deal with the usual singularity of solutions at t = 0. We establish the existence and uniqueness of the numerical solution, and derive a hptype error estimates under L2(I)-norm for the transformed VIEs. Numerical results are provided to show the effectiveness of the proposed methods.
Why do authoritarian regimes try to improve the quality of their governance? In the absence of democratic institutions to monitor, reward and punish their performance, authoritarian politicians are normally expected to seek their self-interest through corruption and rewards to cronies, rather than providing for the public welfare. However, the Chinese state has actively promoted improved governance in recent years, with greater attention to quality of life issues to balance the primary focus on sustaining rapid economic growth. This paper analyses intra-national variation in the provision of public goods in urban China and the impact of public goods on regime support. Does better governance lead to higher levels of public support for the regime, even in the absence of democratic elections? Our evidence suggests that it does, with a greater impact for the local level than for the centre.
Current evidence of the relationship between diets and Fe status is mostly derived from studies in developed countries with Western diets, which may not be translatable to Chinese with a predominantly plant-based diet. We extracted data that were nationally sampled from the 2009 wave of China Health and Nutrition Survey; dietary information was collected using 24-h recalls combined with a food inventory for 3 consecutive days. Blood samples were collected to quantify Fe status, and log-ferritin, transferrin receptor and Hb were used as Fe status indicators. In total, 2905 (1360 males and 1545 females) adults aged 18–50 years were included for multiple linear regression and stratified analyses. The rates of Fe deficiency and Fe-deficiency anaemia were 1·6 and 0·7 % for males and 28·4 and 10·7 % for females, respectively. As red meat and haem Fe consumption differed about fifteen to twenty times throughout the five groups, divided by quintiles of animal protein intake per 4·2 MJ/d, only Fe status as indicated by log-ferritin (P=0·019) and transferrin receptor (P=0·024) concentrations in males was shown to be higher as intakes of animal foods increased. Log-ferritin was positively associated with intakes of red meat (B=0·3 %, P=0·01) and haem Fe (B=12·3 %, P=0·010) in males and with intake of non-haem Fe in females (B=2·2 %, P=0·024). We conclude that diet has a very limited association with Fe status in Chinese adults consuming a traditional Chinese diet, and a predominantly plant-based diet may not be necessarily responsible for poor Fe status.
In this study, hematite nanoparticles (α-Fe2O3 NPs) were synthesized by hydrothermal method, with morphologies (e.g., nanorhombohedra, nanobars, and nanospheres) facilely tuned by changing the concentrations of glycol in the hydrothermal solution. Then a low-cost and scalable electrophoretic deposition method was used to fabricate nanostructured α-Fe2O3 films as photoanodes for solar hydrogen generation. It was found that the film of α-Fe2O3 nanobars showed the highest photoelectrochemical (PEC) performance compared to those films of α-Fe2O3 nanorhombohedra and nanospheres, with photocurrent density reaching 0.7 mA/cm2 at 0.6 V versus Ag/AgCl. This PEC improvement may be related to the smaller diameters of nanobars shortening the carrier migration distance, reducing the recombination rate of photo-generated carriers. Moreover, all the α-Fe2O3 films showed much higher PEC performances with surface modified by Sn4+, mainly due to the reduced surface charge recombination, as the Sn4+ doped overlayer passivated surface defects. For the film of α-Fe2O3 nanobars, the photocurrent density was increased by 100%, reaching 1.4 mA/cm2 at 0.6 V versus Ag/AgCl.
The Qiangtang Metamorphic Belt (QMB) was considered to have either formed in situ by amalgmation of the North and South Qiangtang blocks or been underthrust from the Jinsha suture and exhumed in the interior of a single ‘Qiangtang Block’. A new Sphaeroschwagerina fusuline fauna discovered in the Raggyorcaka Lake area supports the interpretation that the North and South Qiangtang blocks were separated by a wide ocean during Asselian (Early Permian) time, indicating that the QMB was formed by the suturing of the Palaeotethys Ocean along the Longmu Co-Shuanghu suture.
The influence of environmental factors on germination and emergence of aryloxyphenoxy propanoate herbicide-resistant (AR) and -susceptible (AS) Asia Minor bluegrass were studied in laboratory and greenhouse experiments. Seeds were collected from AR and AS plants cultivated in separate greenhouses under the same environmental conditions. The results revealed that optimum temperatures for the germination of AS biotype were 10 to 25 C or alternating temperature of 15/5 to 30/20 C and light was not necessary. However, maximum germination occurred at 10 C or 15/5 C, and no germination occurred above 15 C or 25/15 C for the AR biotype. The AS Asia Minor bluegrass was consistently more tolerant to environmental stress, as evidenced by their greater germination at same pH value, osmotic potential, and NaCl concentration at 15/5 C compared to the AR biotype. Higher emergence rates were obtained when seeds were sown on the surface of soil for both biotypes. Emergence percentage of the AR biotype was below 14% when buried, whereas the AS biotype had 20% emergence at 2.5 cm burial depth. It is concluded that several environmental factors affect the germination of Asia Minor bluegrass, and the AS biotype showed higher germination percentage and a wider adaptive range under same treatments compared with the AR biotype. Due to the reduced emergence at depth, deep tillage could be an effective management to reduce AR Asia Minor bluegrass infestation in the following crop.
We consider in this paper numerical approximation of the linear Fluid-Structure Interaction (FSI). We construct a new class of pressure-correction schemes for the linear FSI problem with a fixed interface, and prove rigorously that they are unconditionally stable. These schemes are computationally very efficient, as they lead to, at each time step, a coupled linear elliptic system for the velocity and displacement in the whole region and a discrete Poisson equation in the fluid region.
Toxoplasma gondii is a major cause of congenital brain disease; however, the underlying mechanism of neuropathogenesis in brain toxoplasmosis remains elusive. To explore the role of T. gondii in the development of neural stem cells (NSCs), NSCs were isolated from GD14 embryos of ICR mice and were co-cultured with tachyzoites of T. gondii RH strain. We found that apoptosis levels of the NSCs co-cultured with 1×106 RH tachyzoites for 24 and 48 h significantly increased in a dose-dependent manner, as compared with the control. Western blotting analysis displayed that the protein level of C/EBP homologous protein (CHOP) was up-regulated, and caspase-12 and c-Jun N-terminal kinase (JNK) were activated in the NSCs co-cultured with the parasites. Pretreatment with endoplasmic reticulum stress (ERS) inhibitor (TUDCA) and caspase-12 inhibitor (Z-ATAD-FMK) inhibited the expression or activation of the key molecules involved in the ERS-mediated apoptotic pathway, and subsequently decreased the apoptosis levels of the NSCs induced by the T. gondii. The findings here highlight that T. gondii induced apoptosis of the NSCs through the ERS signal pathway via activation of CHOP, caspase-12 and JNK, which may constitute a potential molecular mechanism responsible for the cognitive disturbance in neurological disorders of T. gondii.
A study of 7,388 consecutive patients after hepatic resection between 2011 and 2012 identified hepatolithiasis, cirrhosis, and intraoperative blood transfusion as the only independent risk factors of both incisional and organ/space surgical site infection (SSI). Patients with these conditions should be cared for with caution to lower SSI rates.
A spectral-element method is developed to solve the scattering problem for time-harmonic sound waves due to an obstacle in an homogeneous compressible fluid. The method is based on a boundary perturbation technique coupled with an efficient spectral-element solver. Extensive numerical results are presented, in order to show the accuracy and stability of the method.
High rate of charge carrier recombination is a critical factor limiting the photocatalytic activity of g-C3N4. In this contribution, we demonstrate that this issue can be alleviated by constructing a plasmonic photocatalyst with tailored plasmonic-metal nanostructures, i.e., core–shell-typed Ag@SiO2 nanoparticles. Compared with pure g-C3N4, the photocatalytic hydrogen production activity was enhanced by 63% for Ag@SiO2/g-C3N4. As analysis from the photoluminescence results, the enhancement could be attributed to that plasmonic nanostructures favored the separation of electron–hole pairs in the semiconductor due to localized surface plasmons resonance effect. It was found that the silica shell between the Ag nanoparticles and g-C3N4 was essential for the better photocatalytic activity of Ag@SiO2/g-C3N4 than that of Ag/g-C3N4 by limiting the energy-loss Förster energy transfer process.
We develop in this paper efficient and robust numerical methods for solving anisotropic Cahn-Hilliard systems. We construct energy stable schemes for the time discretization of the highly nonlinear anisotropic Cahn-Hilliard systems by using a stabilization technique. At each time step, these schemes lead to a sequence of linear coupled elliptic equations with constant coefficients that can be efficiently solved by using a spectral-Galerkin method. We present numerical results that are consistent with earlier work on this topic, and also carry out various simulations, such as the linear bi-Laplacian regularization and the nonlinear Willmore regularization, to demonstrate the efficiency and robustness of the new schemes.
We present an unconditionally energy stable and uniquely solvable finite difference scheme for the Cahn-Hilliard-Brinkman (CHB) system, which is comprised of a Cahn-Hilliard-type diffusion equation and a generalized Brinkman equation mod-eling fluid flow. The CHB system is a generalization of the Cahn-Hilliard-Stokes model and describes two phase very viscous flows in porous media. The scheme is based on a convex splitting of the discrete CH energy and is semi-implicit. The equations at the implicit time level are nonlinear, but we prove that they represent the gradient of a strictly convex functional and are therefore uniquely solvable, regardless of time step size. Owing to energy stability, we show that the scheme is stable in the time and space discrete and norms. We also present an efficient, practical nonlinear multigrid method . comprised of a standard FAS method for the Cahn-Hilliard part, and a method based on the Vanka smoothing strategy for the Brinkman part . for solving these equations. In particular, we provide evidence that the solver has nearly optimal complexity in typical situations. The solver is applied to simulate spinodal decomposition of a viscous fluid in a porous medium, as well as to the more general problems of buoyancy- and boundary-driven flows.
The commonly used incompressible phase field models for non-reactive, binary fluids, in which the Cahn-Hilliard equation is used for the transport of phase variables (volume fractions), conserve the total volume of each phase as well as the material volume, but do not conserve the mass of the fluid mixture when densities of two components are different. In this paper, we formulate the phase field theory for mixtures of two incompressible fluids, consistent with the quasi-compressible theory , to ensure conservation of mass and momentum for the fluid mixture in addition to conservation of volume for each fluid phase. In this formulation, the mass-average velocity is no longer divergence-free (solenoidal) when densities of two components in the mixture are not equal, making it a compressible model subject to an internal con-straint. In one formulation of the compressible models with internal constraints (model 2), energy dissipation can be clearly established. An efficient numerical method is then devised to enforce this compressible internal constraint. Numerical simulations in confined geometries for both compressible and the incompressible models are carried out using spatially high order spectral methods to contrast the model predictions. Numerical comparisons show that (a) predictions by the two models agree qualitatively in the situation where the interfacial mixing layer is thin; and (b) predictions differ significantly in binary fluid mixtures undergoing mixing with a large mixing zone. The numerical study delineates the limitation of the commonly used incompressible phase field model using volume fractions and thereby cautions its predictive value in simulating well-mixed binary fluids.
Percutaneous transcatheter occlusion has benefited thousands of patients suffering from patent foramen ovale and atrial septal defect. However, no general agreement has been reached on the superiority among occluders. Thus, a meta-analysis between the two most commonly adopted types of occluders was conducted.
The literature review has identified relevant studies up to May, 2011 in the databases of PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, and World Health Organization clinical trials registry centre. Meta-analysis was performed in a fixed/random effects model using Revman 5.1.1. Information on complications and outcomes was extracted.
Analysis from included studies reports an outcome in favour of the Amplatzer. The Amplatzer has proven its superiority in efficacy with a significantly lower risk of early (95% confidence interval = 0.09–0.34) and long-term (95% confidence interval = 0.14–0.97) residual shunt rate for atrial septal defect occlusion, although no significant difference in performance has been reported for patent foramen ovale. In addition, the Amplatzer has also remarkably reduced the risk of embolisation by the device (95% confidence interval = 0.07–0.45) for atrial septal defect and new-set atrial fibrillation (95% confidence interval = 0.18–0.48) for patent foramen ovale. On evaluation of recurrent thrombotic events, it was found that the Amplatzer greatly lowered the rate of thrombus formation on the device (95% confidence interval = 0.02–0.21) for patent foramen ovale; however, no statistical difference was found on atrial septal defect evaluation. However, the result indicated no statistically significant difference between the two kinds of occluders in stroke and transient ischaemic attack of patent foramen ovale.
The meta-analysis has proven the Amplatzer to be the superior occluder, serving better prognosis with more fluent procedure and less complications.
An unstructured nodal spectral-element method for the Navier-Stokes equations is developed in this paper. The method is based on a triangular and tetrahedral rational approximation and an easy-to-implement nodal basis which fully enjoys the tensorial product property. It allows arbitrary triangular and tetrahedral mesh, affording greater flexibility in handling complex domains while maintaining all essential features of the usual spectral-element method. The details of the implementation and some numerical examples are provided to validate the efficiency and flexibility of the proposed method.
Energy metabolism, insulin resistance and adiposity have been implicated in breast cancer, but dietary interventions to reduce breast cancer morbidity and mortality have had limited success. MicroRNA (miRNA) are short, non-coding RNA that participate in the control of metabolic processes through the post-transcriptional modification of RNA. We investigated the effect of a low-glycaemic load dietary intervention on miRNA expression, with subsequent bioinformatics pathway analyses to explore metabolic pathways potentially affected by the diet. Total RNA, including miRNA, was isolated from the serum of fourteen otherwise healthy pre-menopausal women with a high breast cancer risk participating in a 12-month dietary intervention designed to lower glycaemic load by at least 15 % from baseline. Genome-wide miRNA expression was conducted using Illumina BeadChips. In the intervention subjects, three differentially expressed miRNA were validated by real-time (RT)-PCR, and in the twenty control participants, four top differentially expressed miRNA were evaluated to confirm a diet effect. In post-intervention v. baseline serum, twenty miRNA were found to be differentially expressed, with twelve up-regulated and eight down-regulated. These differentially expressed miRNA were predicted to be potentially associated with energy balance and cancer pathways based on exploratory enrichment analysis. Quantitative RT-PCR validations in the controls confirmed that the observed miRNA differential expression was dietary intervention induced. Manipulation of dietary glycaemic load has the potential to modify the expression of multiple miRNA predicted to be involved in energy balance and cancer pathways. Further research is necessary to confirm the role of these miRNA in the control of energy metabolism and relationships with cancer-related processes.
This paper introduces the design and kinematic analysis of a 5-DOF (multiple degree of freedom) hybrid-driven MR (Magnetic Resonance) compatible robot for prostate brachytherapy. It can slip the leash of template and rely on the high precise of MR imaging. After a brief introduction on design requirements of MR compatible robot, a description of our robot structure, material selection, hybrid-driven, and control architecture are presented. Secondly, the forward kinematics equations are obtained according to the equivalent diagram of this robot, and the actual workspace can be outlined. This will help the designer to determine whether this robot can be operated in the MR core without intervention with patient. And then, the inverse kinematics equations combined with trajectory planning are used to calculate the actuators movement. This will help the control system to manipulate the robotic accurately. Finally, vision based experiments on phantoms are used to verify the mechanism precision. As the results shown, the needle tip precision of mechanism is 0.9 mm in the general lab environment.