THE SUPERCLOSENESS OF THE FINITE ELEMENT METHOD FOR A SINGULARLY PERTURBED CONVECTION-DIFFUSION PROBLEM ON A BAKHVALOV-TYPE MESH IN 2D

For singularly perturbed convection-diffusion problems,supercloseness analysis of the finite element method is still open on Bakhvalov-type meshes,especially in the case of 2D.The difficulties arise from the width of the mesh in the layer adjacent to the transition point,resulting in a suboptimal estimate for convergence.Existing analysis techniques cannot handle these difficulties well.To fill this gap,here a novel interpolation is designed delicately for the smooth part of the solution,bringing about the optimal supercloseness result of almost order 2 under an energy norm for the finite element method.Our theoretical result is uniform in the singular perturbation parameterεand is supported by the numerical experiments.

Simultaneous CO_(2) capture and thermochemical heat storage by modified carbide slag in coupled calcium looping and CaO/Ca(OH)2 cycles

The simultaneous CO_(2) capture and heat storage performances of the modified carbide slag with byproduct of biodiesel were investigated in the process coupled calcium looping and CaO/Ca(OH)2 thermochemical heat storage using air as the heat transfer fluid.The modified carbide slag with by-product of biodiesel exhibits superior CO_(2) capture and heat storage capacities in the coupled calcium looping and heat storage cycles.The hydration conversion and heat storage density of the modified carbide slag after 30 heat storage cycles are 0.65 mol·mol^(-1) and 1.14 GJ·t^(-1),respectively,which are 1.6 times as high as those of calcined carbide slag.The negative effect of CO_(2) in air as the heat storage fluid on the heat storage capacity of the modified carbide slag is overcome by introducing CO_(2) capture cycles.In addition,the CO_(2) capture reactivity of the modified carbide slag after the multiple calcium looping cycles is enhanced by the introduction of heat storage cycles.By introducing 10 heat storage cycles after the 10th and 15th CO_(2) capture cycles,the CO_(2) capture capacities of the modified carbide slag are subsequently improved by 32%and 43%,respectively.The porous and loose structure of modified carbide slag reduces the diffusion resistances of CO_(2) and steam in the material in the coupled process.The formed CaCO_(3)in the modified carbide slag as a result of air as the heat transfer fluid in heat storage cycles decomposes to regenerate CaO in calcium looping cycles,which improves heat storage capacity.Therefore,the modified carbide slag with by-product of biodiesel seems promising in the coupled calcium looping and CaO/Ca(OH)_(2) heat storage cycles.

Construction and analysis of a plant transformation binary vector pBDGG harboring a bi-directional promoter fusing dual visible reporter genes

The constitutive promoter of cauliflower mosaic virus 35S （CaMV 35S） is a polar unidirectional promoter and is widely used in plant genetic engineering. In the present study, the unidirectional CaMV 35S promoter has been modified to a bi-directional promoter by fusing its minimal promoter element to the 5＇ end of CaMV 35S promoter in the opposite orientation. To qualitatively and quantitatively estimate its bi-directional transcriptional function and activity, two visible reporter genes, gusA （13-glucuronidase, GUS） and gfp （green fluorescent protein, GFP）, were fused to the two ends of the promoter in bi-orientations ending with NOS terminator sequences, respectively. Stable expression of gusA and gfp genes in transgenic tobacco （Nicotiana tabacum L.） was visulized by histochemically staining for GUS and fluorescence microscopic observation under UV for GFP in transgenic plants. The expression of two reporter genes showed that the constructed bi-directional promoter did have the bi-directional transcriptional function in both expected orientations. The quantitative estimation of GUS and GFP were determined on a HITACHI F1000 Fluorescence Spectrophotometer with various wavelengths of excitation and emission. The GUS activity varied from g to 250 pmol 4-MU/min/mg protein and the GFP content varied from 0.9 to 1.8 μg/ mg protein in various lines of transgenic tobacco plants. Higher GUS activity generally coupled with lower GFP content, and vice versa.

Sex differences in estrogen receptor promoter expression in the area postrema

Estrogen receptor a is widely distributed in the rat brain, but the tissue- or target-specificity of the estrogen receptor a gene promoters remains unknown. In the present study, we used transgenic rats expressing enhanced green fluorescent protein under the control of the estrogen receptor a 0/B promoter to examine expression driven by this promoter in two significant nuclei that regulate cardiovascular activity, the area postrema and the nucleus tractus solitarius. Immunohistochemistry showed that enhanced green fluorescent protein-labeled cells were distributed in the area postrema and the nucleus tractus solitarius of both female and male transgenic rats, and a neural network of enhanced green fluorescent protein-positive fibers was seen between the area postrema and the nucleus tractus solitarius. The number of enhanced green fluorescent protein-labeled cells in the area postrema of female rats was significantly higher than in the males, but no significant difference was found in the number of enhanced green fluorescent protein-labeled cells in the nucleus tractus solitarius. The sex differences in the number of enhanced green fluorescent protein-labeled cells in the area postrema was not affected after ovariectomy or 1713-estradiol benzoate treatment in adult rats. Our results suggest that the effects of estrogen in the area postrema are related to the expression of estrogen receptor a under the control of the 0/B promoter, and changes in the sex hormone environment in the adult period do not affect estrogen receptor a expression in the area postrema or the nucleus tractus solitarius.

Effect of propofol pretreatment on apoptosis in rat brain cortex after focal cerebral ischemia and reperfusion

The present study aimed to observe cortical expression of Bcl-2 and Bax,cysteine-dependent aspartate directed proteases-3 activity and apoptotic cell death in a rat model of middle cerebral artery occlusion pretreated with propofol.Results showed that,propofol pretreatment significantly reduced oxidative stress levels and attenuated neuronal apoptosis in the cortex of rats.Propofol pretreatment upregulated Bcl-2 expression,and downregulated Bax expression and cysteine-dependent aspartate directed proteases-3 activity.These findings indicate that propofol pretreatment inhibits cell apoptosis during focal cerebral ischemia/reperfusion injury.This neuroprotective effect is most likely achieved through the Bcl-2/Bax/cysteine-dependent aspartate directed proteases-3 pathway.

Excellent thermoelectric performance predicted in Sb_(2)Te with natural superlattice structure

Using first-principles calculations combined with the Boltzmann transport theory,we explore the thermoelectric properties of natural superlattice(SL)structure Sb_(2)Te.The results show that n-type Sb_(2)Te possesses larger Seebeck coefficient of 249.59(318.87)μV/K than p-type Sb_(2)Te of 219.85(210.38)μV/K and low lattice thermal conductivity of 1.25(0.21)W/mK along the in-plane(out-of-plane)direction at 300 K.The excellent electron transport performance is mainly attributed to steeper density of state around the bottom of conduction band.The ultralow lattice thermal conductivity of Sb_(2)Te is mainly caused by low phonon group velocity and strong anharmonicity.Further analysis shows that the decrease of group velocity comes from flatter dispersion curves which are contributed by the Brillouin-zone folding.The strong anharmonicity is mainly due to the presence of lone-pair electrons in Sb_(2)Te.Combining such a high Seebeck coefficient with the low lattice thermal conductivity,maximum n-type thermoelectric figure of merit(ZT)of 1.46 and 1.38 could be achieved along the in-plane and out-of-plane directions at room temperature,which is higher than the reported values of Sb_(2)Te_(3).The findings presented here provide insight into the transport property of Sb_(2)Te and highlight potential applications of thermoelectric materials at room temperature.

Electronic structure of cuprate-nickelate infinite-layer heterostructure

The discovery of superconductivity in Sr/Ca-doped infinite-layer nickelates Nd(La)NiO_(2)thin films inspired extensive experimental and theoretical research.However,research on the possibilities of enhanced critical temperature by interface heterostructure is still lacking.Due to the similarities of the crystal structure and band structure of infinite-layer nickelate La NiO_(2)and cuprate CaCuO_(2),we investigate the crystal,electronic and magnetic properties of La NiO_(2):CaCuO_(2)heterostructure using density functional theory and dynamical mean-field theory.Our theoretical results demonstrate that,even a very weak inter-layer z-direction bond is formed,an intrinsic charge transfer between Cu-3d_(x^(2)-y^(2))and Ni-3d_((x^(2)-y^(2)))orbitals is obtained.The weak interlayer hopping between Cu and Ni leaves a parallel band contributed by Ni/Cu-3d_((x^(2)-y^(2)))orbitals near the Fermi energy.Such an infinite-layer heterostructure with negligible interlayer interaction and robust charge transfer opens a new way for interface engineering and nickelate superconductors.

Color Cell Image Segmentation Based on Chan-Vese Model for Vector-Valued Images

In this paper, we propose a color cell image segmentation method based on the modified Chan-Vese model for vectorvalued images. In this method, both the cell nuclei and cytoplasm can be served simultaneously from the color cervical cell image. Color image could be regarded as vector-valued images because there are three channels, red, green and blue in color image. In the proposed color cell image segmentation method, to segment the cell nuclei and cytoplasm precisely in color cell image, we should use the coarse-fine segmentation which combined the auto dual-threshold method to separate the single cell connection region from the original image, and the modified C-V model for vectorvalued images which use two independent level set functions to separate the cell nuclei and cytoplasm from the cell body. From the result we can see that by using the proposed method we can get the nuclei and cytoplasm region more accurately than traditional model.

Antioxidant effects of the aqueous extract of turmeric against hydrogen peroxide-induced oxidative stress in spotted seabass(Lateolabrax maculatus)

Intensive aquaculture-induced oxidative stress is detrimental to fish health and yield.Medicinal plants show promise as natural health boosters and antioxidants in the aquaculture industry.Therefore,this work investigated the effects of turmeric aqueous extract(TAE)on the growth performance,antioxidant status,and hydrogen peroxide(H2O2)-induced oxidative stress in spotted seabass(Lateolabrax maculatus).Fish were fed diets supplemented with 0(Con),2(TAE2),or 4(TAE4)g/kg TAE for eight weeks,then were injected with H2O2.The results showed that dietary supplementation of TAE did not affect fish growth,feed utilization,or body composition.TAE treatment increased liver antioxidant enzyme activities and decreased liver malondialdehyde content and serum levels of glutamate oxalate transaminase,glutamate pyruvate transaminase,and lactate dehydrogenase.Furthermore,the increases in mortality,liver malondialdehyde content,and serum biomarkers of liver injury in the H2O2-treated fish were inhibited as a consequence of the TAE treatment.In addition,TAE treatment activated the Nrf2/Keap1 pathway in the liver,supported by the up-regulated expression of nrf2,ho-1,and gclc,and down-regulated keap1 expression.Overall,dietary incorporation of TAE protected against H2O2-induced oxidative stress in spotted seabass probably by enhancing antioxidant capacity through the Nrf2/Keap1 pathway.

Impact of inhaled corticosteroid use on elderly chronic pulmonary disease patients with community acquired pneumonia

To the Editor:With an aging global population,the incidences of community-acquired pneumonia(CAP)and chronic obstructive pulmonary disease(COPD)have signicantly increased.[1]Previous studies have conrmed that COPD and asthma are independently associated with the prevalence of CAP.The use of inhaled corticosteroid(ICS),the cornerstone of treatment for asthma,COPD with frequent acute exacerbations,and asthma-COPD overlap(ACO)may induce changes in the local lung microbiome and abnormal lung immunity,ultimately,causing a signicantly increased risk of pneumonia.However,in cases of pneumonia,the effect of the use of ICS on CAP mortality remains controversial.While data from one study favored the prior use of ICS,which was associated with a signicantly lower short-term mortality rate,[2]other studies have identied no impact on mortality.To date,data on the impact of the use of ICS on mortality,prehospitalization or during hospitalization,are scarce,particularly in the older population.Therefore,this multicenter,retrospective study explored the association between the use of ICS during hospitalization and short-term mortality in older patients with CAP and those with chronic pulmonary disease(CPD).

Crosslinked solubilizer enables nitrate-enriched carbonate polymer electrolytes for stable,high-voltage lithium metal batteries

High-voltage lithium metal batteries(LMBs)have been considered promising next-generation highenergy-density batteries.However,commercial carbonate electrolytes can scarcely be employed in LMBs owing to their poor compatibility with metallic lithium.N,N-dimethylacrylamide(DMAA)-a crosslinkable solubilizer with a high Gutmann donor number-is employed to facilitate the dissolution of insoluble lithium nitrate(LiNO3)in carbonate-based electrolytes and to form gel polymer electrolytes(GPEs)through in situ polymerization.The Lit solvation structure of the GPEs is regulated using LiNO3 and DMAA,which suppresses the decomposition of LiPFe and facilitates the formation of an inorganic-rich solid electrolyte interface.Consequently,the Coulombic efficiency(CE)of the LillCu cell assembled with a GPE increases to 98.5%at room temperature,and the high-voltage LillNCM622 cell achieves a capacity retention of 80.1%with a high CE of 99.5%after 400 cycles.The bifunctional polymer electrolytes are anticipated to pave the way for next-generation high-voltage LMBs.

Tunable siloxane-induced amphiphilic interphase for high-performance gel polymer-based sodium metal batteries

The ever-growing pursuit for high-energy and low-cost rechargeable batteries has driven the ceaseless research on sodium metal batteries(SMBs)with metallic Na anode,a low redox potential of-2.71 V(vs.standard hydrogen electrode),and a high specific capacity of 1166 mAh g-1.However,its hyperreactivity with liquid electrolytes can cause uncontrollable parasitic reactions and raise safety concerns.Therefore,gel polymer electrolytes(GPEs)in SMBs have attracted immense interest owing to their high energy densities and high safety standards[1],[2].

Transient Polymer Hydrogels Based on Dynamic Covalent Borate Ester Bonds

In nature, biological systems maintain their unique structures and functions by using nonequilibrium processes driven by chemical fuels. Inspired by natural systems, transient hydrogel systems based on chemical reaction networks have been developed that are in thermodynamically nonequilibrium states. The formation of dynamic covalent bonds is an effective tool for designing analogous systems. Herein, we design a transient polymer hydrogel based on fuel-mediated covalent borate ester bonds. The pH-sensitive covalent borate ester bond is formed by the reaction between polyvinyl alcohol (PVA) and boric acid (B(OH)_(3)). Sodium hydroxide (NaOH) and 1,3-propanesulfonate (PrS) are used together as the chemical fuels to temporally control the pH of the system. Meanwhile, the lifetime of the transient hydrogel can be simply controlled by adjusting the composition of the chemical fuel, and the cyclic phase transitions can also be achieved. These programmable transient hydrogels have potential applications in the fields of information transmission and fluid guidance.

Solution-processed n-type Bi_2Te_(3-x)Se_x nanocomposites with enhanced thermoelectric performance via liquid-phase sintering

The much slower progress in enhancing the thermoelectric performance of n-type Bi2Te3 than that of p-type Bi2Te3 based materials in the past decade hinders the widespread use in power generation and refrigeration. Here, a facile bottom-up solution-synthesis with spark plasma sintering(SPS) process has been developed to build n-type Bi2Te3-xSex bulk nanocomposites, which substantially improves the power factor and decreases the lattice thermal conductivity by tuning the interface scattering of phonons and electrons. The stoichiometric composition in ternary Bi2Te3-xSex nanocomposites is also tuned to optimize the carrier concentration and lattice thermal conductivity. The optimized bulk nanocomposite Bi2Te2.7Se0.3 exhibits a ZT of 1.1 at^371 K, which is comparable to the corresponding commercially available ingots. Our results demonstrate the great potential of the solution-processed n-type Bi2Te3-xSex nanocomposites for cost-effective thermoelectric applications.

Dietary n-3/n-6 polyunsaturated fatty acid ratio modulates growth performance in spotted seabass(Lateolabrax maculatus)through regulating lipid metabolism,hepatic antioxidant capacity and intestinal health

An 8-week feeding experiment was carried out to explore the effects of dietary n-3/n-6 polyunsaturated fatty acid(PUFA)ratio on growth performance,lipid metabolism,hepatic antioxidant status,and gut flora of spotted seabass(Lateolabrax maculatus).Six experimental diets were formulated to contain different levels of two purified oil sources including docosahexaenoic and eicosapentaenoic acids enriched oil(n-3)and linoleic acid-enriched oil(n-6)leading to n-3/n-6 PUFA ratios of 0.04,0.35,0.66,1.35,2.45 and16.17.Each diet was fed to triplicate groups of juvenile L.maculatus(11.06±0.20 g,30 fish/tank).Final body weight(FBW),weight gain(WG),specific growth rates(SGR),protein efficiency ratio(PER)and feed utilization efficiency increased as n-3/n-6 PUFA ratio increased up to a certain level,and then decreased thereafter.Fish fed the diet with n-3/n-6 PUFA ratio of 0.66 exhibited the highest FBW,WG,SGR and PER and the lowest feed conversion ratio.Lower n-3/n-6 PUFA ratios induced up-regulated expression of lipid synthesis-related genes(fas,acc2 and srebp-1c)and down-regulated expression of lipolysis related genes(atgl,ppara,cpt-1 and aox).Higher expression of lipolysis-related genes(atgl,ppara and cpt-1)was recorded at moderate n-3/n-6 PUFA ratios(0.66 to 1.35).Moreover,inappropriate n-3/n-6 PUFA ratios triggered up-regulation of pro-inflammatory genes(il-6 and tnf-a)and down-regulation of antiinflammatory genes(il-4 and il-10)in the intestine.The diet with n-3/n-6 PUFA ratio of 0.66 inhibited intestine inflammation,improved intestinal flora richness,increased the abundance of beneficial bacteria such as Lactobacillus,Alloprevotella and Ruminococcus,and reduced the abundance of harmful bacteria including Escherichia-Shigella and Enterococcus.In summary,it could be suggested that a dietary n-3/n-6PUFA ratio of 0.66 can improve growth performance and feed utilization in L.maculatus,as is deemed to be mediated through regulation of lipid metabolism and intestinal flora.

Effects of dietary phosphorus level on growth,body composition,liver histology and lipid metabolism of spotted seabass(Lateolabrax maculatus)reared in freshwater

The present study was conducted to determine the effects of dietary phosphorus(P)levels on growth performance,body composition,liver histology and enzymatic activity,and expression of lipid metabolism-related genes in spotted seabass(Lateolabrax maculatus).Seven diets were prepared to contain available P levels of 0.48%(the control group),0.69%,0.89%,1.10%,1.28%,1.51%and 1.77%and feed fish(4.26±0.03 g)to satiety twice daily for 10 weeks.Significantly higher weight gain and specific growth rate were recorded at P levels of 0.69%-1.51%compared to the control group.Feed conversion ratio decreased with increasing P levels up to 0.89%and increased thereafter.The lowest liver lipid content,viscerosomatic index and lipid content of whole-body were obtained in the 0.89%-P group among dietary treatments.P and calcium(Ca)contents in whole body were increased,while liver triglyceride and cholesterol contents were decreased with increasing dietary P levels from 0.48%to 1.77%.The highest activity of hepatic lipase was recorded in the 1.10%-P group among dietary treatments.Compared to the control group,1.10%P enhanced the proportion of HUFA and reduced the proportion of SFA and MUFA.The histological observations showed that P deficiency(0.48%)led to the vacuolization of hepatocytes and increased number of lipid droplets.Meanwhile,overall liver tissue structure was improved when P level increased to 1.28%.Compared to the control group,expression of lipid metabolism-related genes such as FAS,ACC-2 and SREBP-1 was decreased at 0.89%-1.10%P group while an opposite trend was observed in the expression of PPARa2 and CPT-1 genes.The current study showed that 0.89%dietary P levels could promote growth performance of spotted seabass and reduce lipid accumulation in the liver.A broken-line regression analysis based on weight gain showed that the optimum dietary P level(available P)for juvenile spotted seabass reared in freshwater was 0.72%.

Molecular basis for the functions of dominantly active Y35N and inactive D60K Rheb mutants in mTORC1 signaling

Dear Editor,Mammalian target of rapamycin complex 1(mTORC1)serves as a central regulator of cell growth and proliferation by integrating signals from growth factors,nutrients,energy status,and cellular stress(Saxton and Sabatini,2017).A small GTPase,called Ras homolog enriched in brain(Rheb),is a positive regulator of mTORC1.Like other small GTPases,the function of Rheb is dictated by its guanine nucleotide binding states:it is active in the GTP-bound form and inactive in the GDP-bound form(Aspuria and Tamanoi,2004).

Key mechanism of enzymatic dehairing technology for leather-making:permeation behaviors of protease into animal hide and the mechanism of charge regulation

Enzymes have been widely used as alternatives to conventional chemicals in cleaner leather processes due to their advantages of meeting increasing environmental demands.Especially,enzymatic unhairing based on protease has been applied to leather-making for a long time,however,it still has the key problem of slow permeation in the animal hide,resulting in slow unhairing rate,poor hair removal effect,excessive proteolysis of hide collagen,and decreased leather quality.Aiming at the key problem of bio-unhairing technology,fluorescent labeling technique and confocal laser scanning microscopy were used to investigate the protease permeation behaviors into the animal hide based on well-prepared labeled proteases,as well as the quantitative analysis of the protease amount in different hide layers.The results show that the protease mainly permeates the bovine hide through transfollicular routes from the hair side,and although the intercellular-interfibrillar pathway also exists,it does not play an important role.Additionally,the protease permeation behaviors into the hide are greatly impacted by the charge states of the hide and protease proteins,depending on the isoelectric points(pl)of the proteins and solution pH values.When the solution pH is not between the pl values of the two proteins,the similarly charged protease can quickly and deeply penetrate the hide because of the electrostatic repulsion.The established mechanism provides a theoretical basis for developing an efficient enzymatic unhairing technology for leather-making,and this can also be applied to other processes involving the enzyme permeation into the hide or leather.

High fidelity numerical simulations on the unsteady flow field of low-pressure turbine cascades with and without upstream disturbance at moderate Reynolds number

This paper numerically investigates the aerodynamic performance of the T106A low-pressure turbine based with different inflow conditions at moderate Reynolds number by using high performance computing based on high order unstructured methods.Two different inflow conditions respectively of uniform and disturbed are considered,while for the latter a small circular cylinder is placed upstream of the cascade to generate wake turbulence as a long-standing disturbance.A high order Fourier-spectral/hp element method is employed to solve the flow dynamics in the cascade of high complex geometries.Flow transition characteristics are quantified in terms of the distribution of cascade wall surface pressure and friction coefficient,the distribution of wake profile pressure loss and the evolution characteristics of boundary layer flow structures as well.The numerical results show that the current numerical simulations accurately predict the flow transition performance of low-pressure turbine cascades and capture the effects of wake-generated disturbance on the cascade,which is shown to effectively modify the flow transition performance as compared with the uniform inflow case.

Modeling and investigating the detailed characteristics of solar lighting/heating system based on spectrum split of nanofluids

Solar lighting technologies can lead sunlight into indoor actively,which has been proved that has great potential to reduce electric lighting consumption and create a healthy visual environment.In this paper,a mathematics model was developed to explore performance characteristics and economic applicability of solar lighting/heating system that combine ordinary solar lighting system with nanofluids to spectroscopically utilize sunlight.The results show that the luminous efficiency of output visible light can reach at 242 lm/W,which is 1.62-2.42 times higher than that of current LED light.Moreover,it can be found that the energy-saving capacity of this system is remarkable when used in most areas of China.As for Harbin,its annual total solar radiation ranges 4190 MJ/m^(2)to 5020 MJ/m^(2),the system’s annual output energy(per square meter of collection area)is 188.15 kW·h for daylighting and 248.2 kW•h for domestic hot water.Besides,the integrated using of infrared radiation can improve the economy of solar lighting technologies by calculating the comprehensive price of unit output energy.