Tannic acid/Fe^(3+)interlayer for preparation of high-permeability polyetherimide organic solvent nanofiltration membranes for organic solvent separation

Organic solvent nanofiltration(OSN)membranes have a great application prospect in organic solvent separation,but the development of OSN membranes is mainly restricted by trade-off between permeability and rejection rate.In this work,a TA/Fe^(3+)polymer was introduced into polyetherimide(PEI)ultrafiltration membranes crosslinked with hexamethylene diamine as the intermediate layer,and OSN membranes with high separation performance and solvent permeability were obtained through interfacial polymerization and solvent activation.The interlayer with high surface hydrophilicity and a fixed pore structure controlled the adsorption/diffusion of the amine monomer during interfacial polymerization,forming a smooth(average surface roughness<5.5 nm),ultra-thin(separation layer thickness reduced from 150 to 16 nm)and dense surface structure polyamide(PA)layer.The PA-Fe^(3+)_3-HDA/PEI membrane retained more than 94%of methyl blue(BS)in 0.1 g·L^(-1)BS ethanol solution at 0.6 MPa,and the ethanol permeation reached 28.56 L^(-1)·m^(-2)·h^(-1).The average flux recovery ratio(FRR)of PA-Fe^(3+)_(3)-HDA/PEI membrane was found to be 84%,which has better fouling resistance than PA-HDA/PEI membrane,and it was found to have better stability performance through different solvent immersion experiments and continuous operation in 0.1 g·L^(-1)BS ethanol solution.Compared with thin-film composite nanofiltration membranes,the PA-Fe^(3+)_(3)-HDA/PEI membrane can be manufactured from an economical and environment-friendly method and overcomes the trade-off between permeability and rejection rate,showing great application potential in organic solvent separation systems.

Identification and validation of Temozolomide resistance hub gene LncRNA MOCS2-DT in glioblastoma

Background:Temozolomide(TMZ)is an important adjuvant chemotherapy drug after glioma surgery.However,with the progress of treatment,most patients will gradually develop drug resistance.Long non-coding RNA(lncRNA)in the prediction and reversal of chemotherapy drug resistance possesses great potential.Methods:1.The clinical data and RNA expression matrix of glioma patients were downloaded from the Chinese Glioma Genome Atlas(CGGA),and the clinical data and RNA expression profiles of 47 patients who only received TMZ chemotherapy after surgery were selected;2.WGCNA was performed on RNA expression profiles to find modules highly correlated with survival time and lncRNAs with high connectivity in modules.Core lncRNA were further screened from the GEO database(P<0.05);survival analysis,correlation analysis,enrichment analysis and co-expression analysis were performed;and 3.A TMZ concentration gradient induced glioma-resistant cells(U251TR).Cell proliferation toxicity assays and real-time quantitative PCR were used to verify the core lncRNA and identify the biological characteristics of U251TR.Results:1.According to the WGCNA analysis,it was found that the pink module is highly correlated with survival time and that there are 17 core lncRNAs with high connectivity in the pink module.2.The expression of the core lncRNA MOCS2-DT in the U251 resistant strain was significantly lower than that in the sensitive strain(P<0.05).3.U251TR cells had significantly larger cell bodies with irregular shapes.U251TR cells had a stronger tolerance to TMZ than U251 cells,and the resistance index was about four times higher(P<0.05).4.The expression levels of MGMT and ABCG2 in U251TR cells were significantly higher than those in parental U251 cells(P<0.05),and the expression levels of MOCS2-DT in U251TR cells were significantly lower than those in parental U251 cells(P<0.05).5.The survival time and survival rate of patients with low expression of MOCS2-DT were significantly lower than those of patients with high expression of MOCS2-DT in patients who only received TMZ chemotherapy after surgery.6.The enrichment analysis results show that the mRNA co-expressed with MOCS2-DT is enriched in synapse organization,regulation of membrane potential and signal release,indicating that MOCS2-DT is closely related to these functions.Conclusion:Targeted regulation of MOCS2-DT may reverse the drug resistance of glioma,improve the prognosis of patients and prolong the survival time of patients.

Yuzaoea gen. nov., a new biraphid diatom(Bacillariophyceae)genus and its phylogenetic significance

The flexed frustules in pennate diatoms are usually associated with monoraphid diatoms. Interestingly, we found a biraphid diatom species with flexed frustules in an offshore intertidal beach environment on Weizhou Island,Beihai City, Guangxi Zhuang Autonomous Region, China. Therefore, based on morphological characteristics, we described a new genus of diatoms Yuzaoea sinensis gen. et sp. nov. CH Li, HH Liu, YH Gao & CP Chen. The frustule of this genus is characterized by heterogeneous frustule with one concave valve and one convex valve,complete raphe on both valves, straight and moderately eccentric raphe, uniseriate striae and girdle bands with a single row of areolae. The most identifying feature of this genus was the flexed frustule, which is rare in biraphid diatoms and common in monoraphid diatoms. We compared the morphometric characteristics of genus Yuzaoea with genus Rhoikoneis and several genera within the family Rhoicospheniaceae, including Rhoicosphenia,Campylopyxis, and Cuneolus. Phylogenetic analyses based on SSU rRNA and rbc L showed that the genus Yuzaoea was the sister group to the clade of Rhoicosphenia with a high support value(bootstrap values = 100%), and the clade “Yuzaoea+Rhoicosphenia” was sister to the clade of monoraphid diatoms, in which the genera Achnanthidium, Planothidium and some Cocconeis with high support values(bootstrap = 100%).Morphologically, the genus Yuzaoea shares many morphological features with monoraphid diatoms like genera Achnanthidium and Planothidium and the members within the Rhoicospheniaceae. Therefore, based on a combined morphological studies and phylogenetic results we suggested that this branch may represented the evolution of one kind monoraphid diatoms, from biraphid diatoms(e.g. genus Yuzaoea), to incompleted biraphid diatoms(e.g. genera Rhoicosphenia, Campylopyxis), to monoraphid diatoms(e.g. genera Achnanthidium and Planothidium).

SFGA-CPA: A Novel Screening Correlation Power Analysis Framework Based on Genetic Algorithm

Correlation power analysis(CPA)combined with genetic algorithms(GA)now achieves greater attack efficiency and can recover all subkeys simultaneously.However,two issues in GA-based CPA still need to be addressed:key degeneration and slow evolution within populations.These challenges significantly hinder key recovery efforts.This paper proposes a screening correlation power analysis framework combined with a genetic algorithm,named SFGA-CPA,to address these issues.SFGA-CPA introduces three operations designed to exploit CPA characteris-tics:propagative operation,constrained crossover,and constrained mutation.Firstly,the propagative operation accelerates population evolution by maximizing the number of correct bytes in each individual.Secondly,the constrained crossover and mutation operations effectively address key degeneration by preventing the compromise of correct bytes.Finally,an intelligent search method is proposed to identify optimal parameters,further improving attack efficiency.Experiments were conducted on both simulated environments and real power traces collected from the SAKURA-G platform.In the case of simulation,SFGA-CPA reduces the number of traces by 27.3%and 60%compared to CPA based on multiple screening methods(MS-CPA)and CPA based on simple GA method(SGA-CPA)when the success rate reaches 90%.Moreover,real experimental results on the SAKURA-G platform demonstrate that our approach outperforms other methods.

Side-Channel Leakage Analysis of Inner Product Masking

The Inner Product Masking(IPM)scheme has been shown to provide higher theoretical security guarantees than the BooleanMasking(BM).This scheme aims to increase the algebraic complexity of the coding to achieve a higher level of security.Some previous work unfolds when certain(adversarial and implementation)conditions are met,and we seek to complement these investigations by understanding what happens when these conditions deviate from their expected behaviour.In this paper,we investigate the security characteristics of IPM under different conditions.In adversarial condition,the security properties of first-order IPMs obtained through parametric characterization are preserved in the face of univariate and bivariate attacks.In implementation condition,we construct two new polynomial leakage functions to observe the nonlinear leakage of the IPM and connect the security order amplification to the nonlinear function.We observe that the security of IPMis affected by the degree and the linear component in the leakage function.In addition,the comparison experiments from the coefficients,signal-to-noise ratio(SNR)and the public parameter show that the security properties of the IPM are highly implementation-dependent.

MiR-221-3p调控c-Fos/beclin-1对大鼠冠状动脉微栓塞后心肌细胞自噬的影响

目的:探究miR-221-3p介导的c-Fos/beclin-1信号通路在大鼠冠状动脉微栓塞(CME)后对心肌细胞自噬的影响及意义。方法:将24只SD大鼠按随机数字表法分为Sham组(假手术组)、CME组(微栓塞组)、CME+shRNA组(CME+AAV9-miR-221-3p shRNA组)和CME+NC组(CME+AAV9-Control shRNA组),每组6只。经左心室注入微栓塞球建立CME模型,Sham组用等量生理盐水代替。各组术后9 h行心脏超声及心肌肌钙蛋白(IcTn-I)检测;组织取材做苏木精碱性复红苦味酸染色(HBFP)、透射电镜(TEM)、免疫荧光以及实时荧光定量聚合酶链反应(PCR)、蛋白质印迹(Western blot)等评估miR-221-3p介导的c-Fos/beclin-1信号通路在功能、形态和分子方面对CME的影响。结果:CME后心肌细胞中miR-221-3p表达升高,与Sham组相比,心脏功能抑制,cTn-I及心肌微梗死面积明显升高,c-Fos、beclin-1以及自噬指标LC3-Ⅱ蛋白表达降低(P<0.05)。下调miR-221-3p后,与CME组相比,cTn-I及心肌梗死面积显著下降(P<0.05),c-Fos、beclin-1以及LC3-Ⅱ蛋白表达增加(P<0.05),TEM提示自噬泡的双层膜结构数量增加,自噬部分恢复,心肌损伤减轻,心脏功能改善。结论:抑制miR-221-3p可改善大鼠CME后心脏功能,其可能通过c-Fos/beclin-1途径调节心肌自噬参与CME后诱导的心肌损伤。

Effect of continuous annealing temperature on microstructure and properties of ferritic rolled interstitial-free steel

In this report,the microstructure,mechanical properties,and textures of warm rolled interstitial-free steel annealed at four different temperatures(730,760,790,and 820°C)were studied.The overall structural features of specimens were investigated by optical microscopy,and the textures were measured by X-ray diffraction(XRD).Nano-sized precipitates were then observed by a transmission electron microscope(TEM)on carbon extraction replicas.According to the results,with increased annealing temperatures,the ferrite grains grew;in addition,the sizes of Ti_4C_2S_2 and Ti C precipitates also increased.Additionally,the sizes of Ti N and Ti S precipitates slightly changed.When the annealing temperature increased from 730 to 820°C,the yield strength(YS)and the ultimate tensile strength(UTS)showed a decreasing trend.Meanwhile,elongation and the strain harden exponent(n value)increased to 49.6%and 0.34,respectively.By comparing textures annealed at different temperatures,the intensity of{111}texture annealed at 820°C was the largest,while the difference between the intensity of{111}<110>and{111}<112>was the smallest when the annealing temperature was 820°C.Therefore,the plastic strain ratio(r value)annealed at 820°C was the highest.

Expression of p53 in myocardium following coronary microembolization inrats and its significance

Background Cardiomyocyte apoptosis is a primary cause for coronary microembolization （CME）-induced cardiac dysfunction, p53induces cell growth retardation and apoptosis through stress pathway. The present study investigated the mechanism of p53-induced myocar-dial apoptosis and cardiac dysfunction by activating the mitochondrion apoptotic pathway following CME. Methods Forty SD rats wereequally divided into microembolization （CME）, sham operation （sham）, CME＋siRNA-p53, and CME＋control-p53 groups. The CME ratmodel was established by injecting microembolization spheres via the left ventricle. Cardiac ultrasound, TUNEL, fluorescence quantitativePCR, and Western blot were used to assess the cardiac function indicators, cardiomyocyte apoptosis, and the expressions of mRNA and pro-tein in myocardial tissues, respectively. Results Echocardiography revealed a significantly reduced cardiac function of the CME group thanthe sham group while the CME-induced cardiac dysfunction was improved in the CME＋siRNA-p53 group. The indicators of myocardialapoptosis in the CME group increased significantly than the sham group; those of the CME＋siRNA-p53 group decreased significantly thanthe CME group. Fluorescence quantitative PCR and Western blot demonstrated that p53, Bbc3 （PUMA）, and cleaved caspase-3 expressionswere significantly increased, and BCL-2 expression was declined in myocardial tissues of the CME group compared to the sham group. Acontrasting result was observed in the CME＋siRNA-p53 group as compared to the CME group. Conclusions P53 is involved in theCME-induced cardiac dysfunction, which may up-regulate Bbc3 to activate BCL-2/caspase3 mitochondrial apoptotic pathway and inducemyocardial apoptosis. Inhibiting the p53 expression can effectively suppress this pathway, thereby reducing myocardial apoptosis and car-diac dysftmction.

Nicorandil pretreatment inhibits myocardial apoptosis and improves cardiac function after coronary microembolization in rats

Background Nicorandil （NIC） is a vasodilatory drug used to treat angina. However, its efficacy of cardioprotection in coronary mi- croembolization （CME） is largely unknown. This study was undertaken to determine whether nicorandil pretreatment could attenuate myo- cardial apoptosis and improve cardiac function after CME in rats. Methods Forty-five rats were randomly divided into a Sham group, a CME group and a CME ＋ NIC （NIC） group （n = 15 per group）. CME was established by injecting plastic microspheres （42 pm in diameter） into the left ventricle of the rats in all of the groups except the Sham group. The NIC group received nicorandil at 3 mg/kg per day for seven days before the operation. Cardiac fimction was assessed by echocardiography, the expression levels of cleaved caspase-9/8/3 were detected by Western blot, microinfarction area was measured by haematoxylin-basic fuchsin picric acid staining, and myocardial apoptosis was de- tected by TUNEL staining. Results Compared to that in the Sham group, cardiac fimction in the CME group was significantly decreased （P 〈 0.05）. However, compared to the CME group, the NIC group showed improved cardiac function （P 〈 0.05）. The expression levels of cleaved caspase-9/8/3 protein and myocardial apoptosis were dramatically increased in the CME group compared to those in the Sham group （P 〈 0.05）, while the NIC pretreatment group had significantly decreased expression levels of cleaved caspase-9/8/3 protein as well as a de- creased apoptotic rate （P 〈 0.05）. Conclusions NIC pretreatment inhibited CME-induced myocardial apoptosis and improved cardiac func- tion through blockade of the mitochondrial and death receptor-mediated apoptotic pathways.

Ischemia/hypoxia inhibits cardiomyocyte autophagy and promotes apoptosis via the Egr-1/Bim/Beclin-1 pathway

Background Myocardial injury caused by microvascular obstruction(MVO)is characterized by persistent ischemia/hypoxia(IH)of cardiomyocytes after microembolization.Autophagy and Egr-1 were closely associated with various cardiovascular diseases,including MVO.Bim and Beclin-1 are the important genes for autophagy and apoptosis.We aimed to explore whether the Egr-1/Bim/Beclin-1 pathway is involved in regulating autophagy and apoptosis in IH-exposed cardiomyocytes.Methods Neonatal rat cardiomyocytes exposed to the IH environment in vitro were transfected with lentivirus expressing Egr-1 or Egr-1 sh RNA,or further treated with 3-methyladenine(3-MA).The expressions of autophagy and apoptosis-associated genes were evaluated using RT-q PCR and Western blots assays.Autophagic vacuoles and autophagic flux were detected by transmission electron microscopy(TEM)and confocal microscope,respectively.Cell injury was assessed by lactate dehydrogenase(LDH)leakage,and apoptosis was determined by flow cytometry.Results IH exposure elevated Egr-1 and Bim expressions,and decreased Beclin-1 expression in rat cardiomyocytes.Egr-1 overexpression in IH-exposed cardiomyocytes significantly up-regulated the levels of Egr-1 and Bim,and down-regulated the level of Beclin-1.Egr-1 knockdown resulted in down-regulated expressions of Egr-1 and Bim,as well as up-regulated expression of Beclin-1.In addition,Egr-1 knockdown induced autophagy was suppressed by 3-MA treatments.TEM and autophagic flux experiments also confirmed that Egr-1 inhibited autophagy progression in IH-exposed cardiomyocytes.Egr-1 suppression protected cardiomyocytes from IH-induced injury,as evidenced by the positive correlations between Egr-1 expression and LDH leakage or apoptosis index in IH-exposed cardiomyocytes.Conclusions IH-induced cardiomyocyte autophagy and apoptosis are regulated by the Egr-1/Bim/Beclin-1 pathway,which is a potential target for treating cardiomyocyte injury caused by MVO in the IH environment.

Dynamic response of clamped sandwich beams: analytical modeling

An improved analytical model is developed to predict the dynamic response of clamped lightweight sandwich beams with cellular cores subjected to shock loading over the entire span.The clamped face sheets are simplified as a single-degree-of-freedom(SDOF)system,and the core is idealized using the rigid-perfectly-plastic-locking(RPPL)model.Reflection of incident shock wave is considered by incorporating the bending/stretching resistance of the front face sheet and compaction of the core.The model is validated with existing analytical predictions and FE simulation results,with good agreement achieved.Compared with existing analytical models,the proposed model exhibits superiority in two aspects:the deformation resistance of front face sheet during shock wave reflection is taken into account;the effect of pulse shape is considered.The practical application range of the proposed model is therefore wider.

Downregulation of miR-181a-5p alleviates oxidative stress and inflammation in coronary microembolization-induced myocardial damage by directly targeting XIAP

BACKGROUND Coronary microembolization(CME)is a complicated problem that commonly arises in the context of coronary angioplasty.MicroRNAs play crucial roles in cardiovascular diseases.However,the role and mechanism of miR-181a-5p in CME-induced myocardial injury remains unclear.METHODS We established CME rat models.Cardiac function was detected by echocardiography.Haematoxylin-basic fuchsin-picric acid staining was used to measure micro-infarction size.Serum samples and cell culture supernatants were evaluated via enzyme-linked immunosorbent assay.Cellular reactive oxygen species were determined by dichloro-dihydro-fluorescein diacetate assay,and the other oxidative stress related parameters were assayed by spectrophotometry.The dual-luciferase reporter(DLR)assay and RNA pulldown were conducted to validate the association between miR-181a-5p and X-linked inhibitor of apoptosis protein(XIAP).The expression of miR-181a-5p and XIAP mRNA were determined by quantitative reverse transcription polymerase chain reaction.Proteins were evaluated via immunoblotting.The viability of the cell was evaluated via cell counting kit-8 assay.RESULTS The miR-181a-5p level was significantly increased in CME myocardial tissues.Downregulation of miR-181a-5p improved CME-induced cardiac dysfunction and alleviated myocardial oxidative stress and inflammatory injury,whereas miR-181a-5p exhibited the opposite effects.Then,the DLR assay and RNA pulldown results revealed that miR-181a-5p directly targeting on XIAP.The XIAP level was found to be remarkably decreased after CME.XIAP overexpression attenuated CME-induced myocardial oxidative stress and inflammatory injury.Finally,in vitro rescue experiments revealed that knockdown of XIAP could abolish the protective effects of miR-181a-5p knockdown on hypoxia-induced cardiomyocyte oxidative stress and inflammatory injury.CONCLUSIONS Downregulation of miR-181a-5p alleviates CME-induced myocardial damage by suppressing myocardial oxidative stress and inflammation through directly targeting XIAP.

Effect of metoprolol on myocardial apoptosis after coronary microembolization in rats

BACKGROUND： Coronary microembolization （CME） is a serious complication following percutaneous coronary intervention （PCI） in patients with acute coronary syndromes. The use of metoprolol before PCI can significantly protect ischemic myocardium from myocardial damage, but the function of metoprolol in the treatment of CME is not entirely clear. This study was to explore the effect and significance of metoprolol on myocardial apoptosis and caspase-3 activation after CME in rats. METHODS： Thirty rats were randomly divided into three groups including sham-operation （control group）, CME plus saline （CME group）, CME plus metoprolol （metoprolol group）, 10 rats for each group. The CME group was induced by injecting 3 000 polyethylene microspheres （42 tJm） into the left ventricle during a 10-second occlusion of the ascending aorta; the control group was injected with physiological saline instead of microembolization ball; the metoprolol or saline group was given three intravenous bolus injections before CME. Echocardiography, TUNEL staining, and Western blotting were used to evaluate cardiac function, proportion of apoptotic cells and activation of caspase-3 respectively at 6 hours after operation. RESULTS： Echocardiographic parameters displayed that the metoprolol group improved cardiac function significantly compared with the CME group （P〈0.05）. The myocardial apoptotic rate of the CME group as well as the contents of activated caspase-3 increased significantly （P〈0.05）, both of which were ameliorated significantly by metoprolol treatment （P〈0.05）. CONCLUSIONS： This study demonstrates that metoprolol can protect the myocardium during CME in rats by inhibiting apoptosis and improving cardiac function. These results suggest that the inhibition of apoptosis can be a potential therapeutic strategy for the treatment of CME.

Dual-level stress plateaus in honeycombs subjected to impact loading:perspectives from bucklewaves, buckling and cell-wall progressive folding

Dual-level stress plateaus (i.e., relatively short peak stress plateaus, followed by prolonged crushing stress plateaus) in metallic hexagonal honeycombs subjected to out-of-plane impact loading are characterized using a combined numerical and analytical study, with the influence of the strain-rate sensitivity of the honeycomb pare nt material accounted for. The predicti ons are validated against existing experimental measurements, and good agreement is achieved. It is demonstrated that honeycombs exhibit dual-level stress plateaus when bucklewaves are initiated and propagate in cell walls, followed by buckling and progressive folding of the cell walls. The abrupt stress drop from peak to crushing plateau in the compressive stress versus strain curve can be explained in a way similar to the quasi-static buckling of a clamped plate. The duration of the peak stress plateau is more evident for strain-rate insensitive honeycombs.

Two new species from Sulawesi and Borneo facilitate phylogeny and taxonomic revision of Engelhardia(Juglandaceae)

Engelhardia,a genus of Juglandaceae(the walnut family),is endemic to tropical and subtropical Asia.The rich Cenozoic fossil records and distinctive morphological characters of the living plants have been used to explore the evolutionary history and geographic distribution of Juglandaceae.However,the taxonomy of this genus has been suffered from a lack of in-depth investigation and good specimens across its distribution ranges.Species delimitation of Engelhardia was defined with seven species in 2020,but detailed information on the circumscription of the species still remains poorly understood.In this study,two new species are described from Sulawesi and Borneo,Engelhardia anminiana and E.borneensis.We also revised and reconstructed the phylogeny within Engelhardia using morphological,molecular(plastid and ribosomal),and distribution data.We sampled 787 individuals in 80 populations,and all the samples were genotyped using plastid regions,trnS-trnG,rps16,trnL-trnF,psbA-trnH,and rpl32-trnL;one ribosomal region,nuclear ribosomal internal transcribed spacer(nrITS).The all datasets were used to reconstruct the phylogenetic relationships.Then,the molecular analyses were combined for 738 sheets of specimens with 15 morphological characteristics to further explore the morphological clusters of Engelhardia.Cluster analysis using morphological data confirmed the delimitation of nine Engelhardia species.Also,phylogenetic analysis based on molecular data(i.e.,plastid and ribosomal)supported the monophyly of Engelhardia and generated phylogenetic trees that included E.fenzelii,E.roxburghiana,E.borneensis,E.hainanensis,E.anminiana,E.serrata,E.villosa,E.apoensis and the varieties of E.spicata(i.e.,E.spicata var.spicata,E.spicata var.rigida,E.spicata var.aceriflora,and E.spicata var.colebrookeana).Our comprehensive taxonomic revision of Engelhardia will provide an insight into understanding the plant diversity in tropical and subtropical Asia.

GLOBAL EXISTENCE AND POINTWISE ESTIMATES OF SOLUTIONS TO GENERALIZED KURAMOTO-SIVASHINSKY SYSTEM IN MULTI-DIMENSIONS

The Cauchy problem of the generalized Kuramoto-Sivashinsky equation in multidimensions(n ≥ 3) is considered. Based on Green's function method, some ingenious energy estimates are given. Then the global existence and pointwise convergence rates of the classical solutions are established. Furthermore, the L^p convergence rate of the solution is obtained.

Synthesis of high purity Li2CO3 and MgCO3·3H2O in a homogeneous-like organic phase

Herein, three kinds of Li2CO3 and two kinds of MgCO3·3H2O crystals are easily synthesized in a homogeneouslike organic phase. The morphology and size of synthesized crystals are controllable and adjustable in the single organic phase, with the morphology of Li2CO3 ranging from micro-flaky, flower to nanobranch, MgCO3·3H2O rangi ng from nanosphere to nanorod. Compared with coupled reacti on and solve nt extraction process, of which the crystallization process occurred in the interface of two phase, our proposed method made it possible that the crystallization process occurred in the single organic phase, which resulted in better crystal morphology. Moreover, the formation mechanism of different crystal morphologies is discussed, the results showed that the crystals in micron size and nano size are involved in two crystallization mechanism, the micron particles in the form of flake and flower-like is a typical radial growth, which means that the growth occurs by diffusion around a nucleus as starting point, while the reaction model for small particles should be similar to a water-in-oil structure. As the reaction carried out, the crystal should be restricted in a constrained organic structure.

Effect of long-period stacking ordered structure on very high cycle fatigue properties of Mg-Gd-Y-Zn-Zr alloys

Magnesium alloys with a long-period stacking ordered(LPSO)structure usually possess excellent static strength,but their fatigue behaviors are poorly understood.This work presents the effect of the LPSO structure on the crack behaviors of Mg alloys in a very high cycle fatigue(VHCF)regime.The LPSO lamellas lead to a facet-like cracking process along the basal planes at the crack initiation site and strongly prohibit the early crack propagation by deflecting the growth direction.The stress intensity factor at the periphery of the faceted area is much higher than the conventional LPSO-free Mg alloys,contributing higher fatigue crack propagation threshold of LPSO-containing Mg alloys.Microstructure observation at the facets reveals a layer of ultrafine grains at the fracture surface due to the cyclic contact of the crack surface,which supports the numerous cyclic pressing model describing the VHCF crack initiation behavior.

利用PACS系统提高临床专业医学生的影像诊断思维能力

医学影像存档与通信系统(picture archiving andcommunication system, PACS)已在临床工作中广泛应用。中南大学湘雅医院尝试将PACS 充分运用到临床专业医学生影像诊断教学的各个环节中,取得了良好的效果。

神经外科手术患者预后预测指标的回顾性分析

目的为神经外科手术患者预后提供有效的预测指标,为手术和围术期麻醉提供科学的依据,分析麻醉分级预测神经外科手术患者的预后。方法选取2013年4~5月中南大学湘雅医院行神经外科手术505例患者,对患者的多项临床资料进行分析,包括基础资料:患者性别、年龄、病因类型、手术方式、高血压;患者术前状况评估:格拉斯哥昏迷评分(GCS评分)、麻醉分级、ASA分级、急性生理及慢性健康状况评分系统(APACHEⅡ)、手术分级;术中因素:手术持续时间、术中心血管事件有无、术中输血有无及术后发热,共计14项因素。以患者出院时格拉斯哥预后评分(GOS评分)评判预后,遴选出差异有统计学意义的变量,再应用回归分析讨论影响患者预后的影响因素。结果ASA分级、麻醉分级及术前APACHⅡ评分与GOS评分相关(P<0.05)。结论在ASA分级、麻醉分级、术前APACHEⅡ评分这3项可作为预测预后的指标,麻醉分级是最有效的预测指标。