Accelerated fracture healing by osteogenic Ti45Nb implants through the PI3K–Akt signaling pathway

The key to managing fracture is to achieve stable internal fixation,and currently,biologically and mechanically appropriate internal fixation devices are urgently needed.With excellent biocompatibility and corrosion resistance,titanium–niobium alloys have the potential to become a new generation of internal fixation materials for fractures.However,the role and mechanism of titanium–niobium alloys on promoting fracture healing are still undefined.Therefore,in this study,we systematically evaluated the bone-enabling properties of Ti45Nb via in vivo and in vitro experiments.In vitro,we found that Ti45Nb has an excellent ability to promote MC3T3-E1 cell adhesion and proliferation without obvious cytotoxicity.Alkaline phosphatase(ALP)activity and alizarin red staining and semiquantitative analysis showed that Ti45Nb enhanced the osteogenic differentiation of MC3T3-E1 cells compared to the Ti6Al4V control.In the polymerase chain reaction experiment,the expression of osteogenic genes in the Ti45Nb group,such as ALP,osteopontin(OPN),osteocalcin(OCN),type 1 collagen(Col-1)and runt-related transcription factor-2(Runx2),was significantly higher than that in the control group.Meanwhile,in the western blot experiment,the expression of osteogenic-related proteins in the Ti45Nb group was significantly increased,and the expression of PI3K–Akt-related proteins was also higher,which indicated that Ti45Nb might promote fracture healing by activating the PI3K–Akt signaling pathway.In vivo,we found that Ti45Nb implants accelerated fracture healing compared to Ti6Al4V,and the biosafety of Ti45Nb was confirmed by histological evaluation.Furthermore,immunohistochemical staining confirmed that Ti45Nb may promote osteogenesis by upregulating the PI3K/Akt signaling pathway.Our study demonstrated that Ti45Nb exerts an excellent ability to promote fracture healing as well as enhance osteoblast differentiation by activating the PI3K/Akt signaling pathway,and its good biosafety has been confirmed,which indicates its clinical translation potential.

Mechanism of microarc oxidation on AZ91D Mg alloy induced byβ-Mg_(17)Al_(12) phase

This work proposed a strategy of indirectly inducing uniform microarc discharge by controlling the content and distribution ofβ-Mg_(17)Al_(12)phase in AZ91D Mg alloy.Two kinds of nano-particles(ZrO_(2)and TiO_(2))were designed to be added into the substrate of Mg alloy by friction stir processing(FSP).Then,Mg alloy sample designed with different precipitated morphology ofβ-Mg_(17)Al_(12)phase was treated by microarc oxidation(MAO)in Na_(3)PO_(4)/Na2SiO3electrolyte.The characteristics and performance of the MAO coating was analyzed using scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),contact angle meter,and potentiodynamic polarization.It was found that the coarseα-Mg grains in extruded AZ91D Mg alloy were refined by FSP,and theβ-Mg_(17)Al_(12)phase with reticular structure was broken and dispersed.The nano-ZrO_(2)particles were pinned at the grain boundary by FSP,which refined theα-Mg grain and promoted the precipitation ofβ-Mg_(17)Al_(12)phase in grains.It effectively inhibited the“cascade”phenomenon of microarcs,which induced the uniform distribution of discharge pores.The MAO coating on Zr-FSP sample had good wettability and corrosion resistance.However,TiO_(2)particles were hardly detected in the coating on TiFSP sample.

Wideband radar cross-section reduction by a double-layer-plasma-based metasurface

Reduction of the radar cross-section(RCS) is the key to stealth technology. To improve the RCS reduction effect of the designed checkerboard metasurface and overcome the limitation of thinlayer plasma in RCS reduction technology, a double-layer-plasma-based metasurface—composed of a checkerboard metasurface, a double-layer plasma and an air gap between them—was investigated. Based on the principle of backscattering cancellation, we designed a checkerboard metasurface composed of different artificial magnetic conductor units;the checkerboard metasurface can reflect vertically incident electromagnetic(EM) waves in four different inclined directions to reduce the RCS. Full-wave simulations confirm that the doublelayer-plasma-based metasurface can improve the RCS reduction effect of the metasurface and the plasma. This is because in a band lower than the working band of the metasurface, the RCS reduction effect is mainly improved by the plasma layer. In the working band of the metasurface,impedance mismatching between the air gap and first plasma layer and between first and second plasma layers cause the scattered waves to become more dispersed, so the propagation path of the EM waves in the plasma becomes longer, increasing the absorption of the EM waves by the plasma. Thus, the RCS reduction effect is enhanced. The double-layer-plasma-based metasurface can be insensitive to the polarization of the incoming EM waves, and can also maintain a satisfactory RCS reduction band when the incident waves are oblique.

Fine mapping of the sex locus in Salix triandra confirms a consistent sex determination mechanism in genus Salix

Salix triandra belongs to section Amygdalinae in genus Salix,which is in a different section from the willow species in which sex determination has been well studied.Studying sex determination in distantly related willow species will help to clarify whether the sexes of different willows arise through a common sex determination system.For this purpose,we generated an intraspecific full-sib F1 population for S.triandra and constructed high-density genetic linkage maps for the crossing parents using restriction site-associated DNA sequencing and following a two-way pseudo-testcross strategy.With the established maps,the sex locus was positioned in linkage group XV only in the maternal map,and no sex linkage was detected in the paternal map.Consistent with previous findings in other willow species,our study showed that chromosome XV was the incipient sex chromosome and that females were the heterogametic sex in S.triandra.Therefore,sex in this willow species is also determined through a ZW sex determination system.We further performed fine mapping in the vicinity of the sex locus with SSR markers.By comparing the physical and genetic distances for the target interval encompassing the sex determination gene confined by SSRs,severe recombination repression was revealed in the sex determination region in the female map.The recombination rate in the confined interval encompassing the sex locus was approximately eight-fold lower than the genome-wide average.This study provides critical information relevant to sex determination in S.triandra.

Experimental investigation of erosion rate for gas-solid two-phase flow in 304 stainless/L245 carbon steel

Erosion is one of the most concerning issues in pipeline flow assurance for the Oil&Gas pipeline industries,which can easily lead to wall thinning,perforation leakage,and other crucial safety risks to the steady operation of pipelines.In this research,a novel experimental device is designed to investigate the erosion characteristics of 304 stainless and L245 carbon steel in the gas-solid two-phase flow.Regarding the impacts on erosion rate,the typical factors such as gas velocity,impact angle,erosion time,particle material and target material are individually observed and comprehensive analyzed with the assistance of apparent morphology characterized via Scanning Electron Microscope.Experimental results show that the severest erosion occurs when the angle reaches approximate 30°whether eroded by type I or type II particles,which is observed in both two types of steel.Concretely,304 stainless steel and L245 carbon steel appear to be cut at low angles,and impacted at high angles to form erosion pits.In the steady operational state,the erosion rate is insensitive to the short erosion time and free from the influences caused by the“erosion latent period”.Based on the comparison between experimental data and numerical results generated by existing erosion models,a modified model with low tolerance(<3%),high feasibility and strong consistency is proposed to make an accurate prediction of the erosion in terms of two types of steel under various industrial conditions.

开发区设立有助于减少企业污染排放吗?——基于中国开发区设立的准自然实验

开发区设立的环境效应是否有助于实现“双碳”目标,抑或有所背离?此问题的回答不仅与如何通过开发区建设实现中国经济高质量增长相关,而且是协同当前积极稳妥推进“碳达峰”“碳中和”以应对气候变化全球治理战略的应有之义。本文基于1998-2013年中国工业企业数据库与中国工业企业污染数据库数据,将开发区这一产业集聚政策视为一场准自然实验,使用双重差分模型考察开发区设立的环境效应,尝试探究开发区设立是否有助于减少企业污染物排放这一亟待厘清的现实问题。本文研究发现:(1)开发区设立使得开发区区域内企业二氧化硫排放量增加了约10.4%-11.3%,区域内企业工业烟(粉)尘排放总量增加了15.9%-16.8%,总体上开发区政策对企业污染排放产生了一定的负外部性,其表现在开发区内集聚企业污染物排放量有所下降,而非集聚企业污染物排放量有所增加;(2)本文进一步探讨了开发区升格政策对于企业污染物排放的影响,结果发现:当省级开发区升级为国家级开发区时,区域内企业污染物排放大幅度下降,企业污染物排放增加的趋势被显著抑制。本研究为政府进一步完善开发区政策、加强开发区内部治理优化、推动本地经济特征与外部环境相适应,为实现开发区内经济高质量发展提供了参考依据。

Volatile metabolites of willows determining host discrimination by adult Plagiodera versicolora

Plagiodera versicolora Laicharting is a highly damaging leaf beetle foraging on willow leaves.In willow germplasm collections,observation has shown that Salix suchowensis Cheng was severely foraged by this leaf beetle while Salix triandra L.was damage free or only slightly damaged.Results of olfactometer bioassays show that the headspace volatiles from leaves of S.triandra significantly repelled adult beetles,suggesting that this species produces volatile repellents against P.versicolora.S.suchowensis had no effect on the beetles.Gas chromatography-mass spec-trometry was carried out to profile the headspace volatile organic compounds and 23 compounds from leaves of the alternate species in significantly different concentrations were detected.The effects of 20 chemical analogs on host discrimination were examined.Olfactory response to these chemicals showed that o-cymene,a S.suchowensis specific constituent,significantly attracted adult P.versicolora.In contrast,cis-3-hexenyl acetate,a constituent concentrated more in S.triandra than in S.suchowensis,significantly repelled beetles.Mixing o-cymene and cis-3-hexenyl acetate in comparable concentrations as in the volatiles of S.suchowensis demonstrated that the latter could mask the attracting effect of the former,causing a neutral response by adult beetles to leaves of S.suchowensis against clean air.In addition,chemical analogs have the same effect as plants when resembling volatile organic compounds in real samples.Two volatile metabolites were detected triggering host discrimination by one of the most damaging insect pests to host and non-host willows.The two metabolites are of considerable potential for use as olfactory signs in manag-ing the beetles.

Denoising of X-ray pulsar observed profile using biorthogonal lifting wavelet transform

In X-ray pulsar-based navigation, strong X-ray background noise leads to a low signal-to-noise ratio（SNR） of the observed profile, which consequently makes it very difficult to obtain an accurate pulse phase that directly determines the navigation precision. This signifies the necessity of denoising of the observed profile. Considering that the ultimate goal of denoising is to enhance the pulse phase estimation, a profile denoising algorithm is proposed by fusing the biorthogonal lifting wavelet transform of the linear phase characteristic with the thresholding technique. The statistical properties of X-ray background noise after epoch folding are studied. Then a wavelet-scale dependent threshold is introduced to overcome correlations between wavelet coefficients. Moreover, a modified hyperbola shrinking function is presented to remove the impulsive oscillations of the observed profile. The results of numerical simulations and real data experiments indicate that the proposed method can effectively improve SNR of the observed profile and pulse phase estimation accuracy, especially in short observation durations. And it also outperforms the Donoho thresholding strategy normally used in combination with the orthogonal discrete wavelet transform.

Dynamics of a Discrete Predator-Prey System with Beddington-DeAngelis Function Response

This paper discusses the dynamic behaviors of a discrete predator-prey system with Beddington-DeAngelis function response. We first show that under some suitable assumption, the system is permanent. Furthermore, by constructing a suitable Lyapunov function, a sufficient condition which guarantee the global attractivity of positive solutions of the system is

Effect of Ultra-high Pressure Treatment on the Quality of Persimmon Pulp

Different pressures and different durations of ultra-high pressure treatment were conducted for persimmon pulp after vacuum packing.The results showed that with the increase of pressure and extension of duration,the total number of bacteria in persimmon pulp decreased gradually.The treatment at 400 MPa for 15 min could meet the requirement of commercial sterility.After treatment,the color and the contents of soluble sugar,soluble solids and titratable acid of persimmon pulp were not changed significantly compared with the control group(P >0.05).The content of vitamin C in persimmon pulp declined gradually with the increase in pressure and time,with the maximum loss of 8.06% observed at 600 MPa for 20 min.Peroxidase( POD) activity also declined gradually with the increase of pressure and time.The activity of polyphenol oxidase( PPO) declined gradually with the increase of time,and increased first and then decreased with the increase of pressure.The content of polyphenols increased first and then decreased with the increase in pressure,and tended to increase overall with the increase in time.Under the treatment of 400 MPa for 20 min,the content of polyphenols reached the maximum.The antioxidant capacity of persimmon pulp after ultra-high pressure treatment was higher than that in the control group,but no significant differences were found among the treatment groups( P > 0.05).Compared with the control group,soluble tannin content was increased after ultra-high pressure treatment,but was far below the critical value for astringency(2 mg/g).In conclusion,ultra-high pressure treatment has only a slight effect on the sensory quality of persimmon pulp and can maintain its nutritional quality to a large extent and improve its antioxidant capacity.Moreover,ultra-high pressure treatment can eliminate astringency completely.

Superhydrophilic–superhydrophobic patterned surfaces:From simplified fabrication to emerging applications

Superhydrophilic–superhydrophobic patterned surfaces constitute a branch of surface chemistry involving the two extreme states of superhydrophilicity and superhydrophobicity combined on the same surface in precise patterns.Such surfaces have many advantages,including controllable wettability,enrichment ability,accessibility,and the ability to manipulate and pattern water droplets,and they offer new functionalities and possibilities for a wide variety of emerging applications,such as microarrays,biomedical assays,microfluidics,and environmental protection.This review presents the basic theory,simplified fabrication,and emerging applications of superhydrophilic–superhydrophobic patterned surfaces.First,the fundamental theories of wettability that explain the spreading of a droplet on a solid surface are described.Then,the fabrication methods for preparing superhydrophilic–superhydrophobic patterned surfaces are introduced,and the emerging applications of such surfaces that are currently being explored are highlighted.Finally,the remaining challenges of constructing such surfaces and future applications that would benefit from their use are discussed.

Model for Predicting Climatic Yield of Sugarcane in Nanning City

According to spatial distribution of climate disasters in Nanning City and physiological and ecological indicator demands of sugarcane,with the aid of HJ- 1 CCD satellite remote sensing images,basic meteorological data and geographic information data,this paper established the model for predicting climatic yield of sugarcane in Nanning City,to predict total yield of sugarcane in Nanning City. Results indicated that the distribution of sugarcane in Nanning City is greatly influenced by drought. In 2010,regions suffered from drought had sugarcane planting area of 346. 20 km2,accounting for 18.88% of the total sugarcane planting area. The influence of frost disaster on distribution of sugarcane in Nanning City is limited. Regions suffered from frost had sugarcane planting area of only 67. 1 km2,taking up 3.75% of the total sugarcane planting area. In 2010,the climatic yield of sugarcane in Nanning City was 8. 8446 million tons. It proved that the prediction accuracy of the model is up to 90%.

Comparative analysis of plastomes in Oxalidaceae:Phylogenetic relationships and potential molecular markers

The wood sorrel family,Oxalidaceae,is mainly composed of annual or perennial herbs,a few shrubs,and trees distributed from temperate to tropical zones.Members of Oxalidaceae are of high medicinal,ornamental,and economic value.Despite the rich diversity and value of Oxalidaceae,few molecular markers or plastomes are available for phylogenetic analysis of the family.Here,we reported four new whole plastomes of Oxalidaceae and compared them with plastomes of three species in the family,as well as the plastome of Rourea microphylla in the closely related family Connaraceae.The eight plastomes ranged in length from 150,673 bp(Biophytum sensitivum)to 156,609 bp(R.microphylla).Genome annotations revealed a total of 129e131 genes,including 83e84 protein-coding genes,eight rRNA genes,37 tRNA genes,and two to three pseudogenes.Comparative analyses showed that the plastomes of these species have minor variations at the gene level.The smaller plastomes of herbs B.sensitivum and three Oxalis species are associated with variations in IR region sizes,intergenic region variation,and gene or intron loss.We identified sequences with high variation that may serve as molecular markers in taxonomic studies of Oxalidaceae.The phylogenetic trees of selected superrosid representatives based on 76 protein-coding genes corroborated the Oxalidaceae position in Oxalidales and supported it as a sister to Connaraceae.Our research also supported the monophyly of the COM(Celastrales,Oxalidales,and Malpighiales)clade.

Nanoparticle-induced drag reduction for polyacrylamide in turbulent flow with high Reynolds numbers

Although having been increasingly studied, there is still controversy as to when the addition of nanoparticles could improve the drag reduction performance of polymer drag reducer and particularly what is the underlying mechanism from the fluid dynamics viewpoint. The drag reduction effects of adding SiO_(2) nanoparticles to various polymer polyacrylamide(PAM) solutions were examined in this work.The optimal combination of SiO_(2) nanoparticles with cationic polyacrylamide was confirmed.Interestingly,the addition of SiO_(2) nanoparticles to cationic polyacrylamide solution was shown to be quite efficient for reducing drag, but only at higher flow rates with Reynolds numbers more than 6000, below which the nanoparticle addition is even negative. The addition of SiO_(2) nanoparticles to the PAM solution is supposed to play a dual role. The first is an increase in flow resistance caused by the Brownian motion of nanoparticles, while the second is a decrease in flow resistance caused by acting as nodes to protect the polymer chain from shear-induced breaking under high shear action. At optimal nanoparticle concentration and under higher Reynolds numbers, the later effect is dominant, which could improve the drag reduction performance of polymer drag reducers. Our work should serve as a guide for the application of natural gas fracturing, where the flow rate is frequently very high.

Tensile Properties and Wear Resistance of Mg Alloy Containing High Si as Implant Materials

Magnesium alloy has been considered as one of the third-generation biomaterials for the regeneration and support of functional bone tissue.As a regeneration implant material with great potential applications,in-situ Mg_(2)Si phase reinforced Mg-6Zn cast alloy was comprehensively studied and expected to possess excellent mechanical properties via the refining and modifying of Mg_(2)Si reinforcements.The present study demonstrates that the primary and eutectic Mg_(2)Si phase can be greatly modified by the yttrium(Y)addition.The size of the primary Mg_(2)Si phases can be reduced to~20μm with an addition of 0.5 wt.%Y.This phenomenon is mainly attributed to the poisoning effect of the Y element.Moreover,wear resistance and tensile properties of the ternary alloy have also been improved by the Y addition.Mg-6Zn-4Si-0.5Y alloy exhibits optimal tensile properties and wears resistance.The ultimate tensile strength and the elongation of the alloy with 0.5 wt.%Y are 50%and 65%higher than those of the ternary alloy,respectively.Excessive Y addition(1.0 wt.%)deteriorates the tensile properties of Mg-Zn-Si alloy.The improvement of the tensile properties is mainly due to the modification of primary and eutectic Mg_(2)Si phases as well as the solid solution strengthening of the Y atoms.This study provides a certain implication for the application of Mg-Zn-Si alloys containing Y elements as regeneration implants.

(DarkAI)Mapping the large-scale density field of dark matter using artificial intelligence

Herein,we present a deep-learning technique for reconstructing the dark-matter density field from the redshift-space distribution of dark-matter halos.We built a UNet-architecture neural network and trained it using the COmoving Lagrangian Acceleration fast simulation,which is an approximation of the N-body simulation with 5123 particles in a box size of 500 h^(-1)Mpc.Further,we tested the resulting UNet model not only with training-like test samples but also with standard N-body simulations,such as the Jiutian simulation with 61443particles in a box size of 1000 h^(-1)Mpc and the ELUCID simulation,which has a different cosmology.The real-space dark-matter density fields in the three simulations can be reconstructed reliably with only a small reduction of the cross-correlation power spectrum at 1%and 10%levels at k=0.1 and 0.3 h Mpc-1,respectively.The reconstruction clearly helps to correct for redshift-space distortions and is unaffected by the different cosmologies between the training(Planck2018)and test samples(WMAP5).Furthermore,we tested the application of the UNet-reconstructed density field to obtain the velocity&tidal field and found that this approach provides better results compared with the traditional approach based on the linear bias model,showing a 12.2%improvement in the correlation slope and a 21.1%reduction in the scatter between the predicted and true velocities.Thus,our method is highly efficient and has excellent extrapolation reliability beyond the training set.This provides an ideal solution for determining the three-dimensional underlying density field from the plentiful galaxy survey data.

Calycosin improves cognitive function in a transgenic mouse model of Alzheimer's disease by activating the protein kinase C pathway

The major pathological changes in Alzheimer＇s disease are beta amyloid deposits and cognitive impairment. Calycosin is a typical phy- toestrogen derived from radix astragali that binds to estrogen receptors to produce estrogen-like effects. Radix astragali Calycosin has been shown to relieve cognitive impairment induced by diabetes mellitus, suggesting calycosin may improve the cognitive function of Alzhei- mer＇s disease patients. The protein kinase C pathway is upstream of the mitogen-activated protein kinase pathway and exerts a neuropro- tective effect by regulating Alzheimer＇s disease-related beta amyloid degradation. We hypothesized that calycosin improves the cognitive function of a transgenic mouse model of Alzheimer＇s disease by activating the protein kinase C pathway. Various doses of calycosin （10, 20 and 40 mg/kg） were intraperitoneally injected into APP/PS1 transgenic mice that model Alzheimer＇s disease. Calycosin diminished hippocampal beta amyloid, Tau protein, interleukin-lbeta, tumor necrosis factor-alpha, acetylcholinesterase and malondialdehyde levels in a dose-dependent manner, and increased acetylcholine and glutathione activities. The administration of a protein kinase C inhibitor, cal- phostin C, abolished the neuroprotective effects of calycosin including improving cognitive ability, and anti-oxidative and anti-inflammato- ry effects. Our data demonstrated that calycosin mitigated oxidative stress and inflammatory responses in the hippocampus of Alzheimer＇s disease model mice by activating the protein kinase C pathway, and thereby improving cognitive function.

The Construction Method for Solving Radial Flow Problem through the Homogeneous Reservoir

On the basis of similar structure of solutions of ordinary differential equation (ODE) boundary value problem, the similar construction method was put forward by solving problems of fluid flow in porous media through the homogeneous reservoir. It is indicate that the pressure distribution of dimensionless reservoir and bottom hole in Laplace space, which take on the radial flow, also shows similar structure, and the internal relationship between the above solutions were illustrated in detail.

A modified lumped parameter model of distribution transformer winding

The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed parameters model can depict the winding characteristics accurately,but it requires complex calculations.Lumped parameter model requires less calculations,but its applicable frequency range is not wide.This paper studies the amplitude-frequency characteristics of the lightning wave,compares the transformer modelling methods and finally proposes a modified lumped parameter model,based on the above comparison.The proposed model minimizes the errors provoked by the lumped parameter approximation,and the hyperbolic functions of the distributed parameter model.By this modification it becomes possible to accurately describe the winding characteristics and rapidly obtain the node voltage response.The proposed model can provide theoretical and experimental support to lightning protection of the distribution transformer.

The genome sequence of star fruit(Averrhoa carambola)

Oxalidaceae is one of the most important plant families in horticulture,and its key commercially relevant genus,Averrhoa,has diverse growth habits and fruit types.Here,we describe the assembly of a high-quality chromosomescale genome sequence for Averrhoa carambola(star fruit).Ks distribution analysis showed that A.carambola underwent a whole-genome triplication event,i.e.,the gamma event shared by most eudicots.Comparisons between A.carambola and other angiosperms also permitted the generation of Oxalidaceae gene annotations.We identified unique gene families and analyzed gene family expansion and contraction.This analysis revealed significant changes in MADS-box gene family content,which might be related to the cauliflory of A.carambola.In addition,we identified and analyzed a total of 204 nucleotide-binding site,leucine-rich repeat receptor(NLR)genes and 58 WRKY genes in the genome,which may be related to the defense response.Our results provide insights into the origin,evolution and diversification of star fruit.