双重异质结构对AZ91挤压板力学性能的影响

研究晶粒尺寸和析出相的双重异质结构对小挤压比制备的AZ91挤压板材力学性能的影响。与挤压比(ER)为12.8的样品(即ER12.8样品)相比,ER3.9和ER6.4样品呈现明显的粗细晶粒层和异质分布的细小弥散的析出相。此外,在ER3.9样品的细晶层中还观察到大量带状析出相。由于异质变形诱导(HDI)力和析出相的平衡,ER6.4样品呈现良好的强度和塑性结合。尽管ER3.9样品表现出最高的HDI力和基面滑移施密特因子,改善了塑性,但更多的带状析出相对恶化其力学性能仍起主导作用。

Pore throat structure heterogeneity and its effect on gas-phase seepage capacity in tight sandstone reservoirs:A case study from the Triassic Yanchang Formation,Ordos Basin

The microscopic heterogeneity of pore-throat structures in tight sandstone is a crucial parameter for understanding the transport mechanism of fluid flow.In this work,we firstly developed the new procedure to characterize the pore size distribution(PSD)and throat size distribution(TSD)by combining the nuclear magnetic resonance(NMR),cast thin section(CTS),and constant-rate mercury injection(CRMI)tests,and used the permeability estimated model to verify the full-scale PSD and TSD.Then,we respectively analyzed the fractal feature of the pore and throat,and characterized the heterogeneity of pores and throats.Finally,we elaborated the effect of the pore and throat heterogeneity on the gas-phase seepage capacity base on the analysis of the simple capillary tube model and gas-flooding experiment.The results showed that(1)The PSD and TSD of the tight sandstone sample ranged from 0.01 to 10 mm and from 0.1 to 57 mm,respectively,mainly contributed by the micropores and mesopores.Meanwhile,the permeability estimated by the PSD and TSD was consistent with the experimental permeability,and relative error was lower than 8%.(2)The PSD and TSD exhibited multifractal characteristics,and singularity strength range,Δα,could be used as the indicator for characterizing the heterogeneity of pore and throat.Furthermore,the throat of the sample showed stronger heterogeneity than that the pore.(3)The throats played an important role for the fluid transport in the tight sandstone,and the effect of the throat heterogeneity on the gas-phase seepage capacity was different under the lower and higher injection pressure.The macropores and micropores maybe respectively become the preferential migration pathways at the lower and higher injection pressure.In the end,the identification plate was established in our paper,and could be described the relationship among the throat heterogeneity,injection pressure,permeability and flow path of the gas phase in the tight sandstone.

CASIA2与PentacamHR测量角膜厚度和前房深度的对比研究

目的:比较新型眼前节相干光层析成像仪CASIA2和PentacamHR两种设备测量角膜顶点厚度、角膜最薄点角膜厚度、角膜最薄点位置和前房深度的差异性、相关性和一致性。方法:前瞻性研究。选择2021-03/04在安徽医科大学附属合肥爱尔眼科医院就诊拟行屈光手术的近视患者40例80眼,分别使用CASIA2和PentacamHR测量角膜顶点厚度、最薄点角膜厚度、最薄点位置和前房深度。采用配对t检验比较各参数的差异性,采用Pearson相关系数和Bland-Altman 95%一致性界限法衡量两种仪器检查结果的相关性和一致性。结果:与PentacamHR相比,CASIA2测量的角膜顶点厚度及角膜最薄点厚度偏小(均P<0.001),但一致性界限窄(-26.6~11.6,-29.53~13.51μm)。CASIA2和PentacamHR测量的前房深度结果无差异(t=1.634,P=0.106),两种仪器测量最薄点位置分布结果显示一致性较好(右眼:Z=0.000,P>0.999;左眼:Z=0.149,P=0.882),角膜最薄点位置的X轴位移和Y轴位移,最薄点相对于角膜顶点的距离结果均无差异(P>0.05)。结论:CASIA2与PentacamHR测量的角膜顶点厚度、角膜最薄点厚度、角膜最薄点位置和前房深度具有较好的一致性。但在临床工作中,应考虑到两种仪器各参数间的微小差异,不建议直接替换使用,同时CASIA2极高的扫描速度使其在临床应用上较PentacamHR具有较大的优势。

三种仪器测量年龄相关性白内障患者术前Kappa角和Alpha角的对比

目的:比较三种不同原理的测量仪对年龄相关性白内障患者Kappa角和Alpha角测量的一致性。方法:采用前瞻性研究。收集我院2020-12-01/12-30拟行白内障超声乳化吸除联合人工晶状体植入手术的年龄相关性白内障患者30例60眼。术前暗室中适应10min后,分别应用iTrace、Lenstar 900和IOL Master 700生物测量仪测量Kappa角和Alpha角。分析三种仪器的差异性和一致性。结果:iTrace、Lenstar 900和IOL Master 700的Kappa角测量结果分别为0.25±0.13、0.19±0.11、0.21±0.11mm(F=1.903,P=0.155),Alpha角测量结果分别为0.31±0.11、0.36±0.16、0.36±0.14mm(F=2.999,P=0.052)。三种仪器Kappa角大于0.5mm的比例分别为3%、2%、2%,Alpha角大于0.5mm的比例分别为5%、15%、22%。Kappa角和Alpha角分布主要是在双眼的颞侧,相对于双眼的Kappa角分布,Alpha角颞侧分布比率更高,且iTrace测量的Alpha角分布较Lenstar 900和IOL Master 700沿水平线分布也更加紧密。每种仪器测量得到的Kappa角和Alpha角之间均呈正相关关系(r=0.2941、0.4082、0.5137,P=0.0226、0.0012,P<0.0001),三种仪器Kappa角测量结果两两间一致性好,Alpha角测量结果两两间一致性较差。结论:白内障患者术前进行多焦点人工晶状体植入决策时,Lenstar 900、IOL Master 700和iTrace之间测量的Alpha角结果一致性较差,临床应用时需参考对比多种仪器测量结果。如白内障患者术前无法得到Alpha角的数据时,三种仪器测量得到的Kappa角均可以为多焦点人工晶状体植入决策提供有用的信息。

Grain refinement and mechanical properties of pure aluminum processed by accumulative extrusion bonding

Ultrafine-grained aluminum processed by a new severe plastic deformation technique, accumulative extrusion bonding (AEB), was investigated. Microstructural characterization indicated good interfacial bonding and an average grain size of ~440 nm was obtained after six passes. Tensile testing revealed that the strength reached the maximum value of 195 MPa and the total elongation exceeded 16% after five passes. The hardness was also significantly improved and almost reached saturation after the first pass. SEM fractography of AEB-processed specimens after tensile test showed that failure mode was shear ductile fracture with elongated shallow dimples. Comparison with conventional accumulative roll bonding indicates that this new AEB technique is more effective in refining grain and improving mechanical properties of the specimens.

Acrylamide neurotoxicity on the cerebrum of weaning rats

The mechanism underlying acrylamide-induced neurotoxicity remains controversial. Previous studies have focused on acrylamide-induced toxicity in adult rodents, but neurotoxicity in weaning rats has not been investigated. To explore the neurotoxic effect of acrylamide on the developing brain, weaning rats were gavaged with 0, 5, 15, and 30 mg/kg acrylamide for 4 consecutive weeks. No obvious neurotoxicity was observed in weaning rats in the low-dose acrylamide group （5 mg/kg）. However, rats from the moderateand high-dose acrylamide groups （15 and 30 mg/kg） had an abnormal gait. Furthermore, biochemical tests in these rats demonstrated that glutamate concentration was significantly reduced, and ^-aminobutyric acid content was significantly increased and was dependent on acrylamide dose. Immunohis- tochemical staining showed that in the cerebral cortex, γ-aminobutyric acid, glutamic acid decarboxylase and glial fibrillary acidic protein expression increased remarkably in the moderate- and high-dose acrylamide groups. These results indicate that in weaning rats, acrylamide is positively associated with neurotoxicity in a dose-dependent manner, which may correlate with upregulation of γ-aminobutyric acid and subsequent neuronal degeneration after the initial acrylamide exposure.

Tailoring AZ91 laminates for combination of strength and ductility

Three types of laminates were designed by alternately stacking AZ91 extruded sheets in different states for extrusion to improve the mechanical properties.The tensile tests revealed that the combination of solid-solution-treated sheets with the aging-treated sheets achieved high tensile strength and ductility,i.e.,ultimate tensile strength of~386 MPa and elongation of~19.8%,respectively.Electron backscatter diffraction(EBSD)and TEM results indicated that the aging-treated layers with more nano-sized precipitates and small grain size provided high strength and reasonable ductility,while the solid-solution-treated layers with low dislocation density facilitated strain hardening.Also,the strong interface bonding between the successive layers played an important role in the enhanced ductility.

Effects of extrusion temperature on microstructure evolution and mechanical properties of heterogeneous Mg−Gd alloy laminates via accumulated extrusion bonding

The influence of extrusion temperature on microstructure and mechanical properties of heterogeneous Mg−1Gd/Mg−13Gd laminate prepared by accumulated extrusion bonding was investigated.The results reveal that the Mg−1Gd/Mg−13Gd laminate forms a significant difference in grain size between the successive layers when extruded at 330℃,and this difference gradually disappears as the extrusion temperature increases from 380 to 430℃.Besides,the growth rate of recrystallized grains in fine-grained layers is faster than that in coarse-grained layers.Moreover,the diffusion ability of Gd element increases with elevating extrusion temperatures,promoting the increase and coarsening of precipitates in fine-grained layers.Tensile tests indicate that the sample extruded at 380℃ has a superior combination of strength and ductility.This is mainly attributed to the synergy of the heterogeneous texture between coarse and fine-grained layers,hetero-deformation induced strengthening and hardening.The fine-grained layers facilitate the activation of prismaticáañslips,while coarse-grained layers make it easier to active basaláañand pyramidalác+añslips,especially for the sample extruded at 380℃.The activation of pyramidalác+añslips contributes to coordinating further plastic deformation.

Effects of the band-filling and Fe/Mo disorder on physical properties of Ca_2FeMoO_6

Both the band filling effect and Fe/Mo disorder have a close correlation with the physical properties of the double perovskite Ca2FeMoO6. Two series of Ca2FeMoO6and Nd0.3Ca1.7FeMoO6ceramics sintered at(1050℃, 1200℃, and 1300℃) were specially designed to comparatively investigate the band-filling effect and Fe/Mo disorder on the physical properties of Ca2FeMoO6. The x-ray diffraction indicates that Fe/Mo disorder is sensitive to the sintering temperature. The magnetization behavior is mainly controlled by the Fe/Mo disorder not by the band filling effect, manifested by a close correlation of saturated magnetization(Ms) with the Fe/Mo disorder. Interestingly, magnetoresistance(MR) property of the same composition is dominantly contributed by the grain boundary strength, which can be expressed by the macroscopic resistivity values. However, the band filling effect caused by the Nd-substitution can decrease the spin polarization, and thus suppress the MR performance fundamentally. Contrary to the MR response, the Curie temperature(TC) shows an obvious optimization due to the band filling effect, which increases the carrier density near the Fermi level responsible for the ferromagnetic coupling interaction strengthen. Maybe, our work can provoke further research interests into the correlation of the band-filling effects and Fe/Mo disorder with the physical properties of other Fe/Mo-based double perovskites.

Inhibitory effect of ZX-1201 on pancreatic cancer and the relevant molecular mechanism

Pancreatic ductal adenocarcinoma(PDAC) is one of the five most malignant cancer.ZX-1201 is one of the active constituents in Alismatis Rhizoma,a well-known traditional Chinese medi.cine with a wide variety of pharmacological properties including diuretic,anti-hyperlipidemic,anti-atheroscle.rotic,anti-cancer,anti-inflammatory and anti-oxidative activities.We investigated the inhibitory effect of ZX-1201 on pancreatic cancer and the relevant molecular mechanism in vitro and in vivo.ZX-1201 inhibited the growth and metastasis of PANC-1 cells in BALB/c nude mice significantly.ZX-1201 inhibited the function of AQP1 via directly interaction and involved in the reversion process of ZX-1201 on TGF-β_1.CTGF was an important protein in the reversion process of ZX-1201 on TGF-β_1.ZX-1201 inhibited the migration of PANC-1 and CPFAC-1 cells induced by TGF-β_1 in vitro.ZX-1201 reversed the down-regu.lated of epithelial markers and up-regulated of mesenchymal markers,as well as the up-regulated of Snail and p-Smad2/3 induced by TGF-β_1.And ZX-1201 reversed Epithelial-Mesenchymal Transition by down-regulating AQP1 and inhibiting translocation of β-catenin,the promotor of CTGF.According to these,ZX-1201 inhibited the migration of pancreatic cancer cells.We concluded that ZX-1201 inhibited the growth and metastasis of PANC-1 cells in vivo significantly.And AQP1,β-catenin and CTGF were the pivotal proteins in the process of ZX-1201 inhibiting PANC-1 cells migration induced by TGF-β_1.

Discovery of natural BH3 mimetics and research on related mechanism

In the past two decades,with the increase of smoking population,more and more people are suffering from small cell lung cancer(SCLC).Besides,it is difficult to find an effective way to cure SCLC,since patience can easily develop drug resistance.On the other hand,with the development of science and technology,people began to study the anti-cancer strategy to increase apoptosis,such as inhibiting the overexpression of survival factors.In these survival factors,BCL-2 family has attracted a lot of attention.BH3-only protein is a member of BCL-2 family and it can directly inhibit the expression of BCL-2 protein,thereby prompting apoptosis.Since the BH3-only protein itself is difficult to become a clinical drug,to find alternatives BH3-only protein-BH3 mimetics is particularly important.Plus,more and more researchers have paid attention on the natural BH3 mimetic since it has less side-effect than artificial BH3 mimetics.To find possible BH3 mimetics,we made a primary screening with this pharma.cophore on a small molecular compounds library via Discovery Studio software.And then MTS assay were introduced to verify the activity of compounds.After that,we use Western Blot and Co-IP meth.ods to test the effect of BH3 mimetics.And finally use CDOCKER to predict the further mechanism on autophagy and apoptosis.In our studies,we found 3 possible BH3 mimetics compounds from 170,000 natural small molecular compounds via pharmacophore-based virtual screening.Furthermore,we dem.onstrated AD23,one of the 3 possible natural BH3 mimetics,induced autophagy and apoptosis simulta.neously in dose-time dependence in SCLC cell line.Finally,we use Molecular Docking to predict the further mechanism on autophagy and apoptosis.We believe our works would provide evidences and clues for the structural optimizing and further study of new drugs in the future.

A new seamoth species of Pegasus(Syngnathiformes:Pegasidae)from the East China Sea

DEAR EDITOR,The Pegasidae family,which includes seven species of seamoths,is widely distributed in the temperate and tropical waters of the Indo-Pacific,ranging from South Africa to Hawaii.In this study,we describe a new species of seamoth,Pegasus sinensis sp.nov.,based on morphological and molecular characterization of 14 specimens collected from the surrounding waters of Xiamen City,Fujian Province,China.The new species differs from closely related P.volitans in both the density and color of spots present on the dorsal and lateral body surfaces.

Sacro-anterior haemangiopericytoma: a case report

Haemangiopericytoma(HPC) is a rare vascular tumor with borderline malignancy, considerable histological variability, and unpredictable clinical and biological behavior. HPC can present a diagnostic challenge because of its indeterminate clinical, radiological, and pathological features. HPC generally presents in adulthood and is equally frequent in both sexes. HPC can arise in any site in the body as a slowly growing and painless mass. The precise cell type origin of HPC is uncertain. One third of HPCs occur in the head and neck areas. Exceptional cases of hemangioblastoma arising outside the head and neck areas have been reported, but little is known about their clinicopathologic and immunohistochemical features. This study reports on a case of a large sacro-anterior HPC in a 65-year-old male.