Stomach cancer is the fourth leading cause of cancer-related deaths worldwide[1].There are approximately one million new cases of gastric cancer worldwide each year,with about 45%occurring in China[1].In China,the num...Stomach cancer is the fourth leading cause of cancer-related deaths worldwide[1].There are approximately one million new cases of gastric cancer worldwide each year,with about 45%occurring in China[1].In China,the number of deaths from gastric cancer ranks second among all tumors each year[2],the majority of patients are diagnosed at an advanced or late stage,making them ineligible for surgical treatment.Some of these patients can regain the opportunity for surgery through conversion therapy,while more patients can only receive comprehensive treatment with cytotoxic drugs,anti-metabolite drugs,DNA-targeting drugs,and targeted drugs[3].展开更多
To further enhance the corrosion resistance of the porous micro-arc oxidation(MAO) ceramic layers on AZ31 magnesium alloy, superhydrophobic Mg-Al layered double hydroxide(LDH) coating was fabricated on MAO-coated AZ31...To further enhance the corrosion resistance of the porous micro-arc oxidation(MAO) ceramic layers on AZ31 magnesium alloy, superhydrophobic Mg-Al layered double hydroxide(LDH) coating was fabricated on MAO-coated AZ31 alloy by using in-situ growth method followed by surface modification with stearic acid. The characteristics of different coatings were investigated by XRD, SEM and EDS. The effect of the hydrothermal treatment time on the formation of the LDH coatings was studied. The results demonstrated that the micro-pores and cracks of MAO coating were gradually sealed via in-situ growing LDH with prolonging hydrothermal treating time. Electrochemical measurement displayed that the lowest corrosion current density, the most positive corrosion potential and the highest impedance modulus were observed for superhydrophobic LDH/MAO coating compared with those of MAO coating and LDH/MAO coating. Immersion experiment proved that the superhydrophobic LDH/MAO coating with the active anti-corrosion capability significantly enhanced the long-term corrosion protection for MAO coated alloy.展开更多
Glyceraldehyde-3-phosphate dehydrogenase （GAPDH）, initially identified as a glycolytic enzyme and considered as a housekeeping gene, is widely used as an internal control in experiments on proteins, mRNA, and DNA. H...Glyceraldehyde-3-phosphate dehydrogenase （GAPDH）, initially identified as a glycolytic enzyme and considered as a housekeeping gene, is widely used as an internal control in experiments on proteins, mRNA, and DNA. However, emerging evidence indicates that GAPDH is implicated in diverse functions independent of its role in energy metabolism; the expression status of GAPDH is also deregulated in various cancer cells. One of the most common effects of GAPDH is its inconsistent role in the determination of cancer cell fate. Furthermore, studies have described GAPDH as a regulator of cell death; other studies have suggested that GAPDH participates in tumor progression and serves as a new therapeutic target. However, related regulatory mechanisms of its numerous cellular functions and deregulated expression levels remain unclear. GAPDH is tightly regulated at transcriptional and pnsttranscriptional levels, which are involved in the regulation of diverse GAPDH functions. Several cancer-related factors, such as insulin, hypoxia inducible factor-1 （HIF-1）, p53, nitric oxide （NO）, and acetylated histone, not only modulate GAPDH gene expression but also affect protein functions via common pathways. Moreover, posttranslational modifications （PTMs） occurring in GAPDH in cancer cells result in new activities unrelated to the original glycnlytic function of GAPDH. In this review, recent findings related to GAPDH transcriptional regulation and PTMs are summarized. Mechanisms and pathways involved in GAPDH regulation and its different roles in cancer cells are also described.展开更多
The Pb39 Bi25 Sn36 alloy was directionally solidified at varied withdrawal rates followed by quenching.From metallographic observation,composition analysis and differential scanning calorimetry(DSC)analysis,the solidi...The Pb39 Bi25 Sn36 alloy was directionally solidified at varied withdrawal rates followed by quenching.From metallographic observation,composition analysis and differential scanning calorimetry(DSC)analysis,the solidification sequence of Pb39 Bi25 Sn36 alloy was characterized.The Sn-dendrite is observed as the primary phase during solidification,followed by theβ(Pb7 Bi3)/Sn divorced eutectic.At lower temperatures,theβ(Pb7 Bi3)/Sn binary eutectic is formed in the interdendritic region.However,the quasi-peritectic reaction[L+α-Pb→β(Pb7 Bi3)+Sn]does not occur as the prediction based on ternary phase diagram analysis,which can be attributed to the unequilibrium solidfication condition.Moreover,the as-cast microstructure is significantly refined with the increasing withdrawal rates.The quenched sample only exhibits the lamellar structure of Sn,β(Pb7 Bi3)and Bi phases.The results can provide instructions to optimize the as-cast microstructure of ternary alloys with quasi-peritectic reaction.展开更多
In order to study and popularize clones from the introduced Robinia pseudoacacia, morphological charac- teristics and leaf nutrition of samples of a three-year-old stand were observed and analyzed during its growing s...In order to study and popularize clones from the introduced Robinia pseudoacacia, morphological charac- teristics and leaf nutrition of samples of a three-year-old stand were observed and analyzed during its growing season. Combined with data on rooting ability, height and basal diameter, comparisons were made on morphological characteris- tics, growth traits and leaf nutrition of 11 introduced R. pseudoacacia clones （two from Hungary and nine from South Ko- rea） and two domestic clones, The results show that there are significant differences in growth and morphological char- acteristics among the 13 clones, but no significant differences in the contents of crude protein and crude fibers in the leaves （p 〉 0.05）. Height and basal diameter growth of clones B and G were recorded as the fastest, while clone H1 was the slowest. Clone H2 had the largest leaflets, three times as large as other clones, while K4 had the heaviest dry weight per 100 leaflets because of its thick leaves. The 13 clones can be divided into four classes based on the number of leaf- lets per compound leaf, i.e., 1-3, 13-17, 15-23 and 21-25. There were significant differences in thorn size： H2, with the largest leaflets had the smallest thorns. While of course all clones produced roots, there were significant differences; clones 2N, K5 and B had many adventitious roots, while clones K3, K4 and H1 had few. Correlation between content of crude protein and （length x width of leaf） was positive （p 〈 0.05）, while correlations of the content of crude protein, with the number of leaflets per compound leaf, petiole length of compound leaf and thorn length were negative （p 〈 0.01）. Plant height and basal diameter were positively correlated with each other （p 〈 0.01） and negatively correlated with base width of thorns （p 〈 0.05）.展开更多
Brief-pulse stimulation at 50 Hz has been shown to terminate afterdischarges observed in epilepsy patients. However, the optimal pulse stimulation parameters for terminating cortical electrical stimulation-induced aft...Brief-pulse stimulation at 50 Hz has been shown to terminate afterdischarges observed in epilepsy patients. However, the optimal pulse stimulation parameters for terminating cortical electrical stimulation-induced afterdischarges remain unclear. In the present study, we examined the effects of different brief-pulse stimulation frequencies（5, 50 and 100 Hz） on cortical electrical stimulation-induced afterdischarges in 10 patients with refractory epilepsy. Results demonstrated that brief-pulse stimulation could terminate cortical electrical stimulation-induced afterdischarges in refractory epilepsy patients. In conclusion,（1） a brief-pulse stimulation was more effective when the afterdischarge did not extend to the surrounding brain area.（2） A higher brief-pulse stimulation frequency（especially 100 Hz） was more likely to terminate an afterdischarge.（3） A low current intensity of brief-pulse stimulation was more likely to terminate an afterdischarge.展开更多
It is generally reported that the grain growth in high-entropy ceramics at high temperatures is relatively slower than that in the corresponding single-component ceramics owing to the so-called sluggish diffusion effe...It is generally reported that the grain growth in high-entropy ceramics at high temperatures is relatively slower than that in the corresponding single-component ceramics owing to the so-called sluggish diffusion effect.In this study,we report a fast grain growth phenomenon in the high-entropy ceramics(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))MgAl_(11)O_(19)(HEMA)prepared by a conventional solid-state reaction method.The results demonstrate that the grain sizes of the as-sintered HEMA ceramics are larger than those of the corresponding five single-component ceramics prepared by the same pressureless sintering process,and the grain growth rate of HEMA ceramics is obviously higher than those of the five single-component ceramics during the subsequent heat treatment.Such fast grain growth phenomenon indicates that the sluggish diffusion effect cannot dominate the grain growth behavior of the current high-entropy ceramics.The X-ray photoelectron spectroscopy(XPS)analysis reveals that there are more oxygen vacancies(OV)in the high-entropy ceramics than those in the single-component ceramics owing to the variable valance states of Eu ion.The high-temperature electrical conductivities of the HEMA ceramics support this analysis.It is considered that the high concentration of OV and its high mobility in HEMA ceramics contribute to the accelerated migration and diffusion of cations and consequently increase the grain growth rate.Based on this study,it is believed that multiple intrinsic factors for the high-entropy ceramic system will simultaneously determine the grain growth behavior at high temperatures.展开更多
Excellent irradiation resistance is the basic property of nuclear materials to keep nuclear safety.The high-entropy design has great potential to improve the irradiation resistance of the nuclear materials,which has b...Excellent irradiation resistance is the basic property of nuclear materials to keep nuclear safety.The high-entropy design has great potential to improve the irradiation resistance of the nuclear materials,which has been proven in alloys.However,whether or not high entropy can also improve the irradiation resistance of ceramics,especially the mechanism therein still needs to be uncovered.In this work,the irradiation and helium(He)behaviors of zirconium carbide(ZrC)-based high-entropy ceramics(HECs),i.e.,(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C,were investigated and compared with those of ZrC under 540 keV He ion irradiation with a dose of 1×10^(17) cm^(−2) at room temperature and subsequent annealing.Both ZrC and(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C maintain lattice integrity after irradiation,while the irradiation-induced lattice expansion is smaller in(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C(0.78%)with highly thermodynamic stability than that in ZrC(0.91%).After annealing at 800℃,ZrC exhibits the residual _(0.2)0%lattice expansion,while(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C shows only 0.10%.Full recovery of the lattice parameter(a)is achieved for both ceramics after annealing at 1500℃.In addition,the high entropy in the meantime brings about the favorable structural evolution phenomena including smaller He bubbles that are evenly distributed without abnormal coarsening or aggregation,segregation,and shorter and sparser dislocation.The excellent irradiation resistance is related to the high-entropy-induced phase stability,sluggish diffusion of defects,and stress dispersion along with the production of vacancies by valence compensation.The present study indicates a high potential of high-entropy carbides in irradiation resistance applications.展开更多
Rare-earth aluminates(REAIOs)are potential thermal barrier coating(TBC)materials,but the relatively high thermal conductivity(ko,~13.6 W·m^(-1)·K^(-1))and low fracture toughness(K_(1c),-1.9 MPa·m^(1/2))...Rare-earth aluminates(REAIOs)are potential thermal barrier coating(TBC)materials,but the relatively high thermal conductivity(ko,~13.6 W·m^(-1)·K^(-1))and low fracture toughness(K_(1c),-1.9 MPa·m^(1/2))limit their application.This work proposed a strategy to improve their properties through the synergistic effects of high-entropy engineering and particulate toughening.High-entropy(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2)AlO_(3))(HEAO)-based particulate composites with different contents of high-entropy(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))_(2)Zr_(2)O_(7)(HEZO)were designed and successfully prepared by solid-state sintering.The high-entropy feature of both the matrix and secondary phases causes the strong phonon scattering and the incorporation of the HEZO secondary phase,remarkedly inhibiting the grain growth of the HEAO phase.As a result,HEAO-xHEZO(x=0,5%,10%,25%,and 50%in volume)ceramic composites show low thermal conductivity and high fracture toughness.Compared to the most commonly applied TBC material-yttria stabilized-zirconia(YSZ),the HEAO-25%HEZO particulate composite has a lower thermal conductivity of 0.96-1.17 W·m^(-1)·K^(-1)(298-1273 K),enhanced fracture toughness of 3.94±0.35 MPa-m,and comparable linear coefficient of thermal expansion(CTE)of 10.5×10^(-6)K^(-1).It is believed that the proposed strategy should be revelatory for the design of new coating materials including TBCs and environmental barrier coatings(EBCs).展开更多
Targeted anticancer drugs block cancer cell growth by interfering with specific signaling pathways vital to carcinogenesis and tumor growth rather than harming all rapidly dividing cells as in cytotoxic chemotherapy.T...Targeted anticancer drugs block cancer cell growth by interfering with specific signaling pathways vital to carcinogenesis and tumor growth rather than harming all rapidly dividing cells as in cytotoxic chemotherapy.The Response Evaluation Criteria in Solid Tumor(RECIST)system has been used to assess tumor response to therapy via changes in the size of target lesions as measured by calipers,conventional anatomically based imaging modalities such as computed tomography(CT),and magnetic resonance imaging(MRI),and other imaging methods.However,RECIST is sometimes inaccurate in assessing the efficacy of targeted therapy drugs because of the poor correlation between tumor size and treatment-induced tumor necrosis or shrinkage.This approach might also result in delayed identification of response when the therapy does confer a reduction in tumor size.Innovative molecular imaging techniques have rapidly gained importance in the dawning era of targeted therapy as they can visualize,characterize,and quantify biological processes at the cellular,subcellular,or even molecular level rather than at the anatomical level.This review summarizes different targeted cell signaling pathways,various molecular imaging techniques,and developed probes.Moreover,the application of molecular imaging for evaluating treatment response and related clinical outcome is also systematically outlined.In the future,more attention should be paid to promoting the clinical translation of molecular imaging in evaluating the sensitivity to targeted therapy with biocompatible probes.In particular,multimodal imaging technologies incorporating advanced artificial intelligence should be developed to comprehensively and accurately assess cancer-targeted therapy,in addition to RECIST-based methods.展开更多
High-entropy pyrochlore-type structures based on rare-earth zirconates are successfully produced by conventional solid-state reaction method. Six rare-earth oxides(La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, and Y2O3) and ZrO2...High-entropy pyrochlore-type structures based on rare-earth zirconates are successfully produced by conventional solid-state reaction method. Six rare-earth oxides(La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, and Y2O3) and ZrO2 are used as the raw powders. Five out of the six rare-earth oxides with equimolar ratio and ZrO2 are mixed and sintered at different temperatures for investigating the reaction process. The results demonstrate that the high-entropy pyrochlores(5RE1/5)2 Zr2O7 have been formed after heated at 1000 ℃. The(5RE1/5)2Zr2O7 are highly sintering resistant and possess excellent thermal stability. The thermal conductivities of the(5RE1/5)2Zr2O7 high-entropy ceramics are below 1 W·m–1·K–1 in the temperature range of 300–1200 ℃. The(5RE1/5)2Zr2O7 can be potential thermal barrier coating materials.展开更多
A high-entropy silicide(HES),(Ti_(0.2) Zr_(0.2) Nb_(0.2) Mo_(0.2) W_(0.2))Si_2 with close-packed hexagonal structure is successfully manufactured through reactive spark plasma sintering at 1300 ℃ for 15 min.The eleme...A high-entropy silicide(HES),(Ti_(0.2) Zr_(0.2) Nb_(0.2) Mo_(0.2) W_(0.2))Si_2 with close-packed hexagonal structure is successfully manufactured through reactive spark plasma sintering at 1300 ℃ for 15 min.The elements in this HES are uniformly distributed in the specimen based on the energy dispersive spectrometer analysis except a small amount of zirconium that is combined with oxygen as impurity particles. The Young's modulus, Poisson's ratio,and Vickers hardness of the obtained(Ti_(0.2) Zr_(0.2) Nb_(0.2) Mo_(0.2) W_(0.2))Si_2 are also measured.展开更多
Ultra-high temperature ceramics(UHTCs)are generally referred to the carbides,nitrides,and borides of the transition metals,with the Group IVB compounds(Zr&Hf)and TaC as the main focus.The UHTCs are endowed with ul...Ultra-high temperature ceramics(UHTCs)are generally referred to the carbides,nitrides,and borides of the transition metals,with the Group IVB compounds(Zr&Hf)and TaC as the main focus.The UHTCs are endowed with ultra-high melting points,excellent mechanical properties,and ablation resistance at elevated temperatures.These unique combinations of properties make them promising materials for extremely environmental structural applications in rocket and hypersonic vehicles,particularly nozzles,leading edges,and engine components,etc.In addition to bulk UHTCs,UHTC coatings and fiber reinforced UHTC composites are extensively developed and applied to avoid the intrinsic brittleness and poor thermal shock resistance of bulk ceramics.Recently,high-entropy UHTCs are developed rapidly and attract a lot of attention as an emerging direction for ultra-high temperature materials.This review presents the state of the art of processing approaches,microstructure design and properties of UHTCs from bulk materials to composites and coatings,as well as the future directions.展开更多
High-entropy ceramics attract more and more attention in recent years.However,mechanical properties especially strength and fracture toughness for high-entropy ceramics and their composites have not been comprehensive...High-entropy ceramics attract more and more attention in recent years.However,mechanical properties especially strength and fracture toughness for high-entropy ceramics and their composites have not been comprehensively reported.In this work,high-entropy(Ti0.2Zr0.2Hf0.2Nb0.2Ta 0.2)B2(HEB)monolithic and its composite containing 20 vol%SiC(HEB–20SiC)are prepared by hot pressing.The addition of SiC not only accelerates the densification process but also refines the microstructure of HEB,resulting in improved mechanical properties.The obtained dense HEB and HEB–20SiC ceramics hot pressed at 1800℃exhibit four-point flexural strength of 339±17 MPa and 447±45 MPa,and fracture toughness of 3.81±0.40 MPa·m1/2 and 4.85±0.33 MPa·m1/2 measured by single-edge notched beam(SENB)technique.Crack deflection and branching by SiC particles is considered to be the main toughening mechanisms for the HEB–20SiC composite.The hardness Hv0.2 of the sintered HEB and HEB–20SiC ceramics is 23.7±0.7 GPa and 24.8±1.2 GPa,respectively.With the increase of indentation load,the hardness of the sintered ceramics decreases rapidly until the load reaches about 49 N,due to the indentation size effect.Based on the current experimental investigation it can be seen that the room temperature bending strength and fracture toughness of the high-entropy diboride ceramics are within ranges commonly observed in structure ceramics.展开更多
Ultra-high temperature ceramics(UHTCs)are considered as a family of nonmetallic and inorganic materials that have melting point over 3000℃.Chemically,nearly all UHTCs are borides,carbides,and nitrides of early transi...Ultra-high temperature ceramics(UHTCs)are considered as a family of nonmetallic and inorganic materials that have melting point over 3000℃.Chemically,nearly all UHTCs are borides,carbides,and nitrides of early transition metals(e.g.,Zr,Hf,Nb,Ta).Within the last two decades,except for the great achievements in the densification,microstructure tailoring,and mechanical property improvements of UHTCs,many methods have been established for the preparation of porous UHTCs,aiming to develop high-temperature resistant,sintering resistant,and lightweight materials that will withstand temperatures as high as 2000℃for long periods of time.Amongst the synthesis methods for porous UHTCs,sol–gel methods enable the preparation of porous UHTCs with pore sizes from 1 to 500μm and porosity within the range of 60%–95%at relatively low temperature.In this article,we review the currently available sol–gel methods for the preparation of porous UHTCs.Templating,foaming,and solvent evaporation methods are described and compared in terms of processing–microstructure relations.The properties and high temperature resistance of sol–gel derived porous UHTCs are discussed.Finally,directions to future investigations on the processing and applications of porous UHTCs are proposed.展开更多
The preparation of high-entropy(HE)ceramics with designed composition is essential for verifying the formability models and evaluating the properties of the ceramics.However,inevitable oxygen contamination in non-oxid...The preparation of high-entropy(HE)ceramics with designed composition is essential for verifying the formability models and evaluating the properties of the ceramics.However,inevitable oxygen contamination in non-oxide ceramics will result in the formation of metal oxide impurity phases remaining in the specimen or even escaping from the specimen during the sintering process,making the elemental compositions of the HE phase deviated from the designed ones.In this work,the preparation and thermodynamic analysis during the processing of equiatomic 9-cation HE carbide(HEC9)ceramics of the IVB,VB,and VIB groups were studied focusing on the removing of the inevitable oxygen impurity existed in the starting carbide powders and the oxygen contamination during the powder mixing processing.The results demonstrate that densification by spark plasma sintering(SPS)by directly using the mixed powders of the corresponding single-component carbides will inhibit the oxygen-removing carbothermal reduction reactions,and most of the oxide impurities will remain in the sample as(Zr,Hf)O_(2)phase.Pretreatment of the mixed powders at high temperatures in vacuum will remove most part of the oxygen impurity but result in a remarkable escape of gaseous Cr owing to the oxygen-removing reaction between Cr_(3)C_(2)and various oxide impurities.It is found that graphite addition enhances the oxygen-removing effect and simultaneously prevents the escape of gaseous Cr.On the other hand,although WC,VC,and Mo2C can also act as oxygen-removing agents,there is no metal-containing gaseous substance formation in the temperature range of this study.By using the heat-treated powders with added graphite,equiatomic HEC9 ceramics were successfully prepared by SPS.展开更多
There is a strength and fracture toughness tradeoff in nanoceramic composite. The strength varies reciprocally with the grain size whereas the toughness contributed by compressive residual stress increases with the di...There is a strength and fracture toughness tradeoff in nanoceramic composite. The strength varies reciprocally with the grain size whereas the toughness contributed by compressive residual stress increases with the dimension of the second phase. In this work, a novel duplex microstructure with reinforced clusters composing of nanosized grains was proposed and validated using a model system of B_(4)C-TiB_(2) ceramics densified by carbide boronizing. As-obtained ceramics exhibit excellent combined mechanical properties at room temperature, including Vickers hardness, Young's modulus, flexural strength and fracture toughness(by surface crack in flexure method) of 32.1 ± 2.7 GPa, 506.9 ± 2.0 GPa,1175 ± 71 MPa and 5.1 ± 0.4 MPa m^(0.5), respectively. Both strength and toughness are at least ~30 % higher than the counterparts with similar composition but homogenously distributed TiB_(2) grains. Graphite onion was confirmed to be an intermediate product during reactive sintering, it facilitated the grain pullout during fracture and retained the nanometric TiB_(2) grain in the cluster, both of which also contribute the toughening and strengthening mechanisms in the B_(4)C-TiB_(2) ceramics.展开更多
Background:Patients with temporal lobe epilepsy(TLE)originating from different seizure onset zones had distinct electrophysiological characteristics and surgical outcomes.In this study,we aimed to investigate the rela...Background:Patients with temporal lobe epilepsy(TLE)originating from different seizure onset zones had distinct electrophysiological characteristics and surgical outcomes.In this study,we aimed to investigate the relationship between the origin and prognosis of TLE,and the stereoelectroencephalography(SEEG)features.Methods:Thirty patients with TLE,who underwent surgical treatment in our functional neurosurgery department from January 2016 to December 2017,were enrolled in this study.All patients underwent anterior temporal lobectomy after an invasive preoperative evaluation with SEEG.Depending on the epileptic focus location,patients were divided into those with medial temporal lobe seizures(MTLS)and those with lateral temporal lobe seizures(LTLS).The Engel classification was used to evaluate operation effectiveness,and the Kaplan-Meier analysis was used to detect seizure-free duration.Results:The mean follow-up time was 25.7±4.8 months.Effectiveness was 63.3%for Engel I(n=19),13.3%for Engel II,3.3%for Engel III,and 20.0%for Engel IV.According to the SEEG,60.0%(n=18)had MTLS,and 40.0%(n=12)had LTLS.Compared with the MTLS group,the operation age of those with LTLS was significantly greater(26.9±6.9 vs.29.9±12.5 years,t=-0.840,P=0.009)with longer epilepsy duration(11.9±6.0 vs.17.9±12.1 years,t=-1.801,P=0.038).Patients with MTLS had a longer time interval between ictal onset to seizure(67.3±59.1 s vs.29.3±24.4 s,t=2.017,P=0.008).The most common SEEG ictal pattern was a sharp/spike-wave rhythm in the MTLS group(55.6%)and low-voltage fast activity in the LTLS group(58.3%).Compared with the LTLS group,patients with MTLS had a more favorable prognosis(41.7%vs.77.8%,P=0.049).Post-operative recurrence was more likely to occur within three months after the operation for both groups,and there appeared to be a stable longterm outcome.Conclusion:Patients with MTLS,who accounted for three-fifths of patients with TLE,showed a more favorable surgical outcome.展开更多
To clarify the solidification behavior of Re- and Ru-containing Ni-based single-crystal superalloys, four experimental alloys with varied contents of Re and Ru were investigated by differential scanning calorimetry （...To clarify the solidification behavior of Re- and Ru-containing Ni-based single-crystal superalloys, four experimental alloys with varied contents of Re and Ru were investigated by differential scanning calorimetry （DSC） and metallographic techniques. To obtain the - solvus temperatures, the stepwise solution and aging heat treatments were used. DSC analysis shows that Re leads to the increase in freezing range and γ-solvus temperature. On the contrast, Ru only has negligible influence on the freezing range, but leads to the lower γ-solvus temperature. In comparison with Ru, Re leads to more severe segregation and higher eutectic fractions in as-cast microstructures. Furthermore, the castability and phase stability of Ni-based superalloys were analyzed by the results of DSC and metallographic analysis, such as freezing range, critical nucleation temperature, γ-solvus temperature and eutectic fractions. It shows that Re leads to the wider freezing range and lower critical nucleation temperature, indicating the worse castability of Re-con- taining Ni-based single-crystal superalloys.展开更多
An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quan- titatively estimate the interfacial energy of the nanostructured multilayer films （NMFs） adherent to flexi...An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quan- titatively estimate the interfacial energy of the nanostructured multilayer films （NMFs） adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be ~ 5.0 J/m2 for Cu/Cr, ~4.1 J/m2 for Cu/Ta, ~ 2.8 J/m2 for Cu/Mo, ~ 1.1 J/m2 for Cu/Nb, and ~ 1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.展开更多
文摘Stomach cancer is the fourth leading cause of cancer-related deaths worldwide[1].There are approximately one million new cases of gastric cancer worldwide each year,with about 45%occurring in China[1].In China,the number of deaths from gastric cancer ranks second among all tumors each year[2],the majority of patients are diagnosed at an advanced or late stage,making them ineligible for surgical treatment.Some of these patients can regain the opportunity for surgery through conversion therapy,while more patients can only receive comprehensive treatment with cytotoxic drugs,anti-metabolite drugs,DNA-targeting drugs,and targeted drugs[3].
基金Project(17JS083) supported by the Key Laboratory Program of Shaanxi Education Department,ChinaProject(2016JZ018) supported by the Key Program of Natural Science Research of Shaanxi Province,ChinaProject(51701162) supported by the National Natural Science Foundation of China
文摘To further enhance the corrosion resistance of the porous micro-arc oxidation(MAO) ceramic layers on AZ31 magnesium alloy, superhydrophobic Mg-Al layered double hydroxide(LDH) coating was fabricated on MAO-coated AZ31 alloy by using in-situ growth method followed by surface modification with stearic acid. The characteristics of different coatings were investigated by XRD, SEM and EDS. The effect of the hydrothermal treatment time on the formation of the LDH coatings was studied. The results demonstrated that the micro-pores and cracks of MAO coating were gradually sealed via in-situ growing LDH with prolonging hydrothermal treating time. Electrochemical measurement displayed that the lowest corrosion current density, the most positive corrosion potential and the highest impedance modulus were observed for superhydrophobic LDH/MAO coating compared with those of MAO coating and LDH/MAO coating. Immersion experiment proved that the superhydrophobic LDH/MAO coating with the active anti-corrosion capability significantly enhanced the long-term corrosion protection for MAO coated alloy.
文摘Glyceraldehyde-3-phosphate dehydrogenase （GAPDH）, initially identified as a glycolytic enzyme and considered as a housekeeping gene, is widely used as an internal control in experiments on proteins, mRNA, and DNA. However, emerging evidence indicates that GAPDH is implicated in diverse functions independent of its role in energy metabolism; the expression status of GAPDH is also deregulated in various cancer cells. One of the most common effects of GAPDH is its inconsistent role in the determination of cancer cell fate. Furthermore, studies have described GAPDH as a regulator of cell death; other studies have suggested that GAPDH participates in tumor progression and serves as a new therapeutic target. However, related regulatory mechanisms of its numerous cellular functions and deregulated expression levels remain unclear. GAPDH is tightly regulated at transcriptional and pnsttranscriptional levels, which are involved in the regulation of diverse GAPDH functions. Several cancer-related factors, such as insulin, hypoxia inducible factor-1 （HIF-1）, p53, nitric oxide （NO）, and acetylated histone, not only modulate GAPDH gene expression but also affect protein functions via common pathways. Moreover, posttranslational modifications （PTMs） occurring in GAPDH in cancer cells result in new activities unrelated to the original glycnlytic function of GAPDH. In this review, recent findings related to GAPDH transcriptional regulation and PTMs are summarized. Mechanisms and pathways involved in GAPDH regulation and its different roles in cancer cells are also described.
基金National Natural Science Foundation of China(No.51604222)China Postdoctoral Science Foundation(No.152064),Strong Industrial Base Project of China(No.TC160A310-18)+1 种基金Xi'an University of Science and Technology for Excellent Young Teachers Research Program(No.2018YQ2-12)Excellent Projects funded by Science and Technology Activities for Overseas Students in Shaanxi Province(No.2018047).
文摘The Pb39 Bi25 Sn36 alloy was directionally solidified at varied withdrawal rates followed by quenching.From metallographic observation,composition analysis and differential scanning calorimetry(DSC)analysis,the solidification sequence of Pb39 Bi25 Sn36 alloy was characterized.The Sn-dendrite is observed as the primary phase during solidification,followed by theβ(Pb7 Bi3)/Sn divorced eutectic.At lower temperatures,theβ(Pb7 Bi3)/Sn binary eutectic is formed in the interdendritic region.However,the quasi-peritectic reaction[L+α-Pb→β(Pb7 Bi3)+Sn]does not occur as the prediction based on ternary phase diagram analysis,which can be attributed to the unequilibrium solidfication condition.Moreover,the as-cast microstructure is significantly refined with the increasing withdrawal rates.The quenched sample only exhibits the lamellar structure of Sn,β(Pb7 Bi3)and Bi phases.The results can provide instructions to optimize the as-cast microstructure of ternary alloys with quasi-peritectic reaction.
基金financially supported by the National Key Technology R&D Program (No. 2006BAD01A1601)the National High Technology Research and Development Program of China (863 Program, No. 2007AA100105)+1 种基金the Special Fund for Agro-scientific Research in the Public Interest (No. 200803034)the Key ResearchProgram of the State Forestry Administration of China (No. 2004-04)
文摘In order to study and popularize clones from the introduced Robinia pseudoacacia, morphological charac- teristics and leaf nutrition of samples of a three-year-old stand were observed and analyzed during its growing season. Combined with data on rooting ability, height and basal diameter, comparisons were made on morphological characteris- tics, growth traits and leaf nutrition of 11 introduced R. pseudoacacia clones （two from Hungary and nine from South Ko- rea） and two domestic clones, The results show that there are significant differences in growth and morphological char- acteristics among the 13 clones, but no significant differences in the contents of crude protein and crude fibers in the leaves （p 〉 0.05）. Height and basal diameter growth of clones B and G were recorded as the fastest, while clone H1 was the slowest. Clone H2 had the largest leaflets, three times as large as other clones, while K4 had the heaviest dry weight per 100 leaflets because of its thick leaves. The 13 clones can be divided into four classes based on the number of leaf- lets per compound leaf, i.e., 1-3, 13-17, 15-23 and 21-25. There were significant differences in thorn size： H2, with the largest leaflets had the smallest thorns. While of course all clones produced roots, there were significant differences; clones 2N, K5 and B had many adventitious roots, while clones K3, K4 and H1 had few. Correlation between content of crude protein and （length x width of leaf） was positive （p 〈 0.05）, while correlations of the content of crude protein, with the number of leaflets per compound leaf, petiole length of compound leaf and thorn length were negative （p 〈 0.01）. Plant height and basal diameter were positively correlated with each other （p 〈 0.01） and negatively correlated with base width of thorns （p 〈 0.05）.
基金supported by the Capital Health Research and Development Special Funds of China,No.2016-1-2011
文摘Brief-pulse stimulation at 50 Hz has been shown to terminate afterdischarges observed in epilepsy patients. However, the optimal pulse stimulation parameters for terminating cortical electrical stimulation-induced afterdischarges remain unclear. In the present study, we examined the effects of different brief-pulse stimulation frequencies（5, 50 and 100 Hz） on cortical electrical stimulation-induced afterdischarges in 10 patients with refractory epilepsy. Results demonstrated that brief-pulse stimulation could terminate cortical electrical stimulation-induced afterdischarges in refractory epilepsy patients. In conclusion,（1） a brief-pulse stimulation was more effective when the afterdischarge did not extend to the surrounding brain area.（2） A higher brief-pulse stimulation frequency（especially 100 Hz） was more likely to terminate an afterdischarge.（3） A low current intensity of brief-pulse stimulation was more likely to terminate an afterdischarge.
基金support from the National Natural Science Foundation of China (Nos.52032001 and 52211540004)the Fundamental Research Funds for the Central Universities (No.2232021A-01).
文摘It is generally reported that the grain growth in high-entropy ceramics at high temperatures is relatively slower than that in the corresponding single-component ceramics owing to the so-called sluggish diffusion effect.In this study,we report a fast grain growth phenomenon in the high-entropy ceramics(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))MgAl_(11)O_(19)(HEMA)prepared by a conventional solid-state reaction method.The results demonstrate that the grain sizes of the as-sintered HEMA ceramics are larger than those of the corresponding five single-component ceramics prepared by the same pressureless sintering process,and the grain growth rate of HEMA ceramics is obviously higher than those of the five single-component ceramics during the subsequent heat treatment.Such fast grain growth phenomenon indicates that the sluggish diffusion effect cannot dominate the grain growth behavior of the current high-entropy ceramics.The X-ray photoelectron spectroscopy(XPS)analysis reveals that there are more oxygen vacancies(OV)in the high-entropy ceramics than those in the single-component ceramics owing to the variable valance states of Eu ion.The high-temperature electrical conductivities of the HEMA ceramics support this analysis.It is considered that the high concentration of OV and its high mobility in HEMA ceramics contribute to the accelerated migration and diffusion of cations and consequently increase the grain growth rate.Based on this study,it is believed that multiple intrinsic factors for the high-entropy ceramic system will simultaneously determine the grain growth behavior at high temperatures.
基金financially supported by the National Natural Science Foundation of China(52032001,52102081,and 51532009)Shanghai Sailing Program(20YF1455500)+1 种基金Science and Technology Commission of Shanghai Municipality(16DZ2260603)Shanghai Technical Platform for Testing and Characterization on Inorganic Materials(19DZ2290700).
文摘Excellent irradiation resistance is the basic property of nuclear materials to keep nuclear safety.The high-entropy design has great potential to improve the irradiation resistance of the nuclear materials,which has been proven in alloys.However,whether or not high entropy can also improve the irradiation resistance of ceramics,especially the mechanism therein still needs to be uncovered.In this work,the irradiation and helium(He)behaviors of zirconium carbide(ZrC)-based high-entropy ceramics(HECs),i.e.,(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C,were investigated and compared with those of ZrC under 540 keV He ion irradiation with a dose of 1×10^(17) cm^(−2) at room temperature and subsequent annealing.Both ZrC and(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C maintain lattice integrity after irradiation,while the irradiation-induced lattice expansion is smaller in(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C(0.78%)with highly thermodynamic stability than that in ZrC(0.91%).After annealing at 800℃,ZrC exhibits the residual _(0.2)0%lattice expansion,while(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C shows only 0.10%.Full recovery of the lattice parameter(a)is achieved for both ceramics after annealing at 1500℃.In addition,the high entropy in the meantime brings about the favorable structural evolution phenomena including smaller He bubbles that are evenly distributed without abnormal coarsening or aggregation,segregation,and shorter and sparser dislocation.The excellent irradiation resistance is related to the high-entropy-induced phase stability,sluggish diffusion of defects,and stress dispersion along with the production of vacancies by valence compensation.The present study indicates a high potential of high-entropy carbides in irradiation resistance applications.
基金financial supports from the National Natural Science Foundation of China(Nos.52032001 and 52211540004)the Fundamental Research Funds for the Central Universities(No.2232021A-01).
文摘Rare-earth aluminates(REAIOs)are potential thermal barrier coating(TBC)materials,but the relatively high thermal conductivity(ko,~13.6 W·m^(-1)·K^(-1))and low fracture toughness(K_(1c),-1.9 MPa·m^(1/2))limit their application.This work proposed a strategy to improve their properties through the synergistic effects of high-entropy engineering and particulate toughening.High-entropy(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2)AlO_(3))(HEAO)-based particulate composites with different contents of high-entropy(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))_(2)Zr_(2)O_(7)(HEZO)were designed and successfully prepared by solid-state sintering.The high-entropy feature of both the matrix and secondary phases causes the strong phonon scattering and the incorporation of the HEZO secondary phase,remarkedly inhibiting the grain growth of the HEAO phase.As a result,HEAO-xHEZO(x=0,5%,10%,25%,and 50%in volume)ceramic composites show low thermal conductivity and high fracture toughness.Compared to the most commonly applied TBC material-yttria stabilized-zirconia(YSZ),the HEAO-25%HEZO particulate composite has a lower thermal conductivity of 0.96-1.17 W·m^(-1)·K^(-1)(298-1273 K),enhanced fracture toughness of 3.94±0.35 MPa-m,and comparable linear coefficient of thermal expansion(CTE)of 10.5×10^(-6)K^(-1).It is believed that the proposed strategy should be revelatory for the design of new coating materials including TBCs and environmental barrier coatings(EBCs).
基金This work was supported by the National Natural Science Foundation of China(Nos.32171363,82103614,and 81901801)Fujian Major Scientific and Technological Special Project for“Social Development”(No.2020YZ016002)+5 种基金Natural Science Foundation of Fujian Province of China(No.2021J05007)Natural Science Foundation of Guangdong Province(No.2021A1515011180)Xiamen Municipal Bureau of Science and Technology(Nos.3502Z20194040 and 3502Z20209101)Research Fund of Fujian Key Laboratory of Precision Diagnosis and Treatment in Breast Cancer&Xiamen Key Laboratory of Endocrine-Related Cancer Precision Medicine(XKLEC2020KF01)Youth Fund of Xiang’an Hospital of Xiamen University(PM202103050001)Xiamen’s Key Laboratory of Precision Medicine for Endocrine-Related Cancers,and start-up fund from Xiamen University and Shantou Central Hospital Research Incubation Program(201905).We thank Drs.Kang-Lang Lou,Min Wei,Yi-Yang Gao,Xue-Qi Fan,Qiu-Min Deng,Yi-Fei Pei,Hong-Yu Chen,Zhong Luo,Xiao Shen,and Cheng-Xi Li for their kind help in this study.
文摘Targeted anticancer drugs block cancer cell growth by interfering with specific signaling pathways vital to carcinogenesis and tumor growth rather than harming all rapidly dividing cells as in cytotoxic chemotherapy.The Response Evaluation Criteria in Solid Tumor(RECIST)system has been used to assess tumor response to therapy via changes in the size of target lesions as measured by calipers,conventional anatomically based imaging modalities such as computed tomography(CT),and magnetic resonance imaging(MRI),and other imaging methods.However,RECIST is sometimes inaccurate in assessing the efficacy of targeted therapy drugs because of the poor correlation between tumor size and treatment-induced tumor necrosis or shrinkage.This approach might also result in delayed identification of response when the therapy does confer a reduction in tumor size.Innovative molecular imaging techniques have rapidly gained importance in the dawning era of targeted therapy as they can visualize,characterize,and quantify biological processes at the cellular,subcellular,or even molecular level rather than at the anatomical level.This review summarizes different targeted cell signaling pathways,various molecular imaging techniques,and developed probes.Moreover,the application of molecular imaging for evaluating treatment response and related clinical outcome is also systematically outlined.In the future,more attention should be paid to promoting the clinical translation of molecular imaging in evaluating the sensitivity to targeted therapy with biocompatible probes.In particular,multimodal imaging technologies incorporating advanced artificial intelligence should be developed to comprehensively and accurately assess cancer-targeted therapy,in addition to RECIST-based methods.
基金Financial support from the National Natural Science Foundation of China (Nos. 51532009, 51602324, and 51872405) are gratefully acknowledged.
文摘High-entropy pyrochlore-type structures based on rare-earth zirconates are successfully produced by conventional solid-state reaction method. Six rare-earth oxides(La2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, and Y2O3) and ZrO2 are used as the raw powders. Five out of the six rare-earth oxides with equimolar ratio and ZrO2 are mixed and sintered at different temperatures for investigating the reaction process. The results demonstrate that the high-entropy pyrochlores(5RE1/5)2 Zr2O7 have been formed after heated at 1000 ℃. The(5RE1/5)2Zr2O7 are highly sintering resistant and possess excellent thermal stability. The thermal conductivities of the(5RE1/5)2Zr2O7 high-entropy ceramics are below 1 W·m–1·K–1 in the temperature range of 300–1200 ℃. The(5RE1/5)2Zr2O7 can be potential thermal barrier coating materials.
基金Financial support from the National Natural Science Foundation of China (Nos. 51532009 and 51872045)the Science and Technology Commission of Shanghai Municipality (No. 18ZR1401400) are gratefully acknowledged
文摘A high-entropy silicide(HES),(Ti_(0.2) Zr_(0.2) Nb_(0.2) Mo_(0.2) W_(0.2))Si_2 with close-packed hexagonal structure is successfully manufactured through reactive spark plasma sintering at 1300 ℃ for 15 min.The elements in this HES are uniformly distributed in the specimen based on the energy dispersive spectrometer analysis except a small amount of zirconium that is combined with oxygen as impurity particles. The Young's modulus, Poisson's ratio,and Vickers hardness of the obtained(Ti_(0.2) Zr_(0.2) Nb_(0.2) Mo_(0.2) W_(0.2))Si_2 are also measured.
基金support from the National Natural Science Foundation of China(52032001,52022072,52032003,51972243,92060202,51872239,51872059,51772061,52061135102,52002321,50632070,51272266,and 52102093)bilateral project of NSFC-JSPS(51111140017 and 51611140121)+4 种基金China Postdoctoral Science Foundation(2021M690817)Fundamental Research Funds for the Central Universities(G2020KY05125)Key Research Program of Frontier Sciences,CAS(QYZDY-SSW-JSC031)the projects supported by fee State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology(2021-KF-5)fee State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(KF2116)are greatly acknowledged.
文摘Ultra-high temperature ceramics(UHTCs)are generally referred to the carbides,nitrides,and borides of the transition metals,with the Group IVB compounds(Zr&Hf)and TaC as the main focus.The UHTCs are endowed with ultra-high melting points,excellent mechanical properties,and ablation resistance at elevated temperatures.These unique combinations of properties make them promising materials for extremely environmental structural applications in rocket and hypersonic vehicles,particularly nozzles,leading edges,and engine components,etc.In addition to bulk UHTCs,UHTC coatings and fiber reinforced UHTC composites are extensively developed and applied to avoid the intrinsic brittleness and poor thermal shock resistance of bulk ceramics.Recently,high-entropy UHTCs are developed rapidly and attract a lot of attention as an emerging direction for ultra-high temperature materials.This review presents the state of the art of processing approaches,microstructure design and properties of UHTCs from bulk materials to composites and coatings,as well as the future directions.
基金This work was supported by the National Natural Science Foundation of China(Nos.51532009,51872045)Science and Technology Commission of Shanghai Municipality(No.18ZR1401400)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.2232018D3-32,2232019A3-13)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(No.19ZK0113).
文摘High-entropy ceramics attract more and more attention in recent years.However,mechanical properties especially strength and fracture toughness for high-entropy ceramics and their composites have not been comprehensively reported.In this work,high-entropy(Ti0.2Zr0.2Hf0.2Nb0.2Ta 0.2)B2(HEB)monolithic and its composite containing 20 vol%SiC(HEB–20SiC)are prepared by hot pressing.The addition of SiC not only accelerates the densification process but also refines the microstructure of HEB,resulting in improved mechanical properties.The obtained dense HEB and HEB–20SiC ceramics hot pressed at 1800℃exhibit four-point flexural strength of 339±17 MPa and 447±45 MPa,and fracture toughness of 3.81±0.40 MPa·m1/2 and 4.85±0.33 MPa·m1/2 measured by single-edge notched beam(SENB)technique.Crack deflection and branching by SiC particles is considered to be the main toughening mechanisms for the HEB–20SiC composite.The hardness Hv0.2 of the sintered HEB and HEB–20SiC ceramics is 23.7±0.7 GPa and 24.8±1.2 GPa,respectively.With the increase of indentation load,the hardness of the sintered ceramics decreases rapidly until the load reaches about 49 N,due to the indentation size effect.Based on the current experimental investigation it can be seen that the room temperature bending strength and fracture toughness of the high-entropy diboride ceramics are within ranges commonly observed in structure ceramics.
基金Financial support from the National Natural Science Foundation of China (Nos. 51602324 and 51532009)the Fundamental Research Funds for the Central Universities (No. 2232018D3-32)
文摘Ultra-high temperature ceramics(UHTCs)are considered as a family of nonmetallic and inorganic materials that have melting point over 3000℃.Chemically,nearly all UHTCs are borides,carbides,and nitrides of early transition metals(e.g.,Zr,Hf,Nb,Ta).Within the last two decades,except for the great achievements in the densification,microstructure tailoring,and mechanical property improvements of UHTCs,many methods have been established for the preparation of porous UHTCs,aiming to develop high-temperature resistant,sintering resistant,and lightweight materials that will withstand temperatures as high as 2000℃for long periods of time.Amongst the synthesis methods for porous UHTCs,sol–gel methods enable the preparation of porous UHTCs with pore sizes from 1 to 500μm and porosity within the range of 60%–95%at relatively low temperature.In this article,we review the currently available sol–gel methods for the preparation of porous UHTCs.Templating,foaming,and solvent evaporation methods are described and compared in terms of processing–microstructure relations.The properties and high temperature resistance of sol–gel derived porous UHTCs are discussed.Finally,directions to future investigations on the processing and applications of porous UHTCs are proposed.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52032001 and 51872045).
文摘The preparation of high-entropy(HE)ceramics with designed composition is essential for verifying the formability models and evaluating the properties of the ceramics.However,inevitable oxygen contamination in non-oxide ceramics will result in the formation of metal oxide impurity phases remaining in the specimen or even escaping from the specimen during the sintering process,making the elemental compositions of the HE phase deviated from the designed ones.In this work,the preparation and thermodynamic analysis during the processing of equiatomic 9-cation HE carbide(HEC9)ceramics of the IVB,VB,and VIB groups were studied focusing on the removing of the inevitable oxygen impurity existed in the starting carbide powders and the oxygen contamination during the powder mixing processing.The results demonstrate that densification by spark plasma sintering(SPS)by directly using the mixed powders of the corresponding single-component carbides will inhibit the oxygen-removing carbothermal reduction reactions,and most of the oxide impurities will remain in the sample as(Zr,Hf)O_(2)phase.Pretreatment of the mixed powders at high temperatures in vacuum will remove most part of the oxygen impurity but result in a remarkable escape of gaseous Cr owing to the oxygen-removing reaction between Cr_(3)C_(2)and various oxide impurities.It is found that graphite addition enhances the oxygen-removing effect and simultaneously prevents the escape of gaseous Cr.On the other hand,although WC,VC,and Mo2C can also act as oxygen-removing agents,there is no metal-containing gaseous substance formation in the temperature range of this study.By using the heat-treated powders with added graphite,equiatomic HEC9 ceramics were successfully prepared by SPS.
基金supported financially by grants from the National Natural Science Foundation of China (NSFC)(No. 51972243 and51521001)。
文摘There is a strength and fracture toughness tradeoff in nanoceramic composite. The strength varies reciprocally with the grain size whereas the toughness contributed by compressive residual stress increases with the dimension of the second phase. In this work, a novel duplex microstructure with reinforced clusters composing of nanosized grains was proposed and validated using a model system of B_(4)C-TiB_(2) ceramics densified by carbide boronizing. As-obtained ceramics exhibit excellent combined mechanical properties at room temperature, including Vickers hardness, Young's modulus, flexural strength and fracture toughness(by surface crack in flexure method) of 32.1 ± 2.7 GPa, 506.9 ± 2.0 GPa,1175 ± 71 MPa and 5.1 ± 0.4 MPa m^(0.5), respectively. Both strength and toughness are at least ~30 % higher than the counterparts with similar composition but homogenously distributed TiB_(2) grains. Graphite onion was confirmed to be an intermediate product during reactive sintering, it facilitated the grain pullout during fracture and retained the nanometric TiB_(2) grain in the cluster, both of which also contribute the toughening and strengthening mechanisms in the B_(4)C-TiB_(2) ceramics.
基金supported by grants from the Beijing Natural Science Foundation(No.L182015)the Beijing Hospitals Authority’s Ascent Plan(No.DFL20190801)。
文摘Background:Patients with temporal lobe epilepsy(TLE)originating from different seizure onset zones had distinct electrophysiological characteristics and surgical outcomes.In this study,we aimed to investigate the relationship between the origin and prognosis of TLE,and the stereoelectroencephalography(SEEG)features.Methods:Thirty patients with TLE,who underwent surgical treatment in our functional neurosurgery department from January 2016 to December 2017,were enrolled in this study.All patients underwent anterior temporal lobectomy after an invasive preoperative evaluation with SEEG.Depending on the epileptic focus location,patients were divided into those with medial temporal lobe seizures(MTLS)and those with lateral temporal lobe seizures(LTLS).The Engel classification was used to evaluate operation effectiveness,and the Kaplan-Meier analysis was used to detect seizure-free duration.Results:The mean follow-up time was 25.7±4.8 months.Effectiveness was 63.3%for Engel I(n=19),13.3%for Engel II,3.3%for Engel III,and 20.0%for Engel IV.According to the SEEG,60.0%(n=18)had MTLS,and 40.0%(n=12)had LTLS.Compared with the MTLS group,the operation age of those with LTLS was significantly greater(26.9±6.9 vs.29.9±12.5 years,t=-0.840,P=0.009)with longer epilepsy duration(11.9±6.0 vs.17.9±12.1 years,t=-1.801,P=0.038).Patients with MTLS had a longer time interval between ictal onset to seizure(67.3±59.1 s vs.29.3±24.4 s,t=2.017,P=0.008).The most common SEEG ictal pattern was a sharp/spike-wave rhythm in the MTLS group(55.6%)and low-voltage fast activity in the LTLS group(58.3%).Compared with the LTLS group,patients with MTLS had a more favorable prognosis(41.7%vs.77.8%,P=0.049).Post-operative recurrence was more likely to occur within three months after the operation for both groups,and there appeared to be a stable longterm outcome.Conclusion:Patients with MTLS,who accounted for three-fifths of patients with TLE,showed a more favorable surgical outcome.
基金financially supported by the National High Technology Research and Development Program of China (No. 2012AA03A511)the National Natural Science Foundation of China (Nos. 51171151 and 51331005)+2 种基金the State Key Laboratory of Solidification Processing in Northwestern Polytechnical University (No. SKLSP201310)the Science and Technology Program of Shaanxi Province(No.2013JQ6003)the Research Foundation of Education Bureau of Shaanxi Province (No. 2013JK0898)
文摘To clarify the solidification behavior of Re- and Ru-containing Ni-based single-crystal superalloys, four experimental alloys with varied contents of Re and Ru were investigated by differential scanning calorimetry （DSC） and metallographic techniques. To obtain the - solvus temperatures, the stepwise solution and aging heat treatments were used. DSC analysis shows that Re leads to the increase in freezing range and γ-solvus temperature. On the contrast, Ru only has negligible influence on the freezing range, but leads to the lower γ-solvus temperature. In comparison with Ru, Re leads to more severe segregation and higher eutectic fractions in as-cast microstructures. Furthermore, the castability and phase stability of Ni-based superalloys were analyzed by the results of DSC and metallographic analysis, such as freezing range, critical nucleation temperature, γ-solvus temperature and eutectic fractions. It shows that Re leads to the wider freezing range and lower critical nucleation temperature, indicating the worse castability of Re-con- taining Ni-based single-crystal superalloys.
基金financially supported by the National Natural Science Foundation of China(Nos.5132100351322104+6 种基金51201123 and 51571157)the National Basic Research Program of China(No.2010CB631003)the 111 Project of China(No.B06025)the support from Fundamental Research Funds for the Central UniversitiesTengfei Scholar projectChina Postdoctoral Science Foundation(No.2012M521765)Shaanxi Province Postdoctoral Scientific Research Projects for part of financial support
文摘An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quan- titatively estimate the interfacial energy of the nanostructured multilayer films （NMFs） adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be ~ 5.0 J/m2 for Cu/Cr, ~4.1 J/m2 for Cu/Ta, ~ 2.8 J/m2 for Cu/Mo, ~ 1.1 J/m2 for Cu/Nb, and ~ 1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.
