Revealing precipitation behavior and mechanical response of wire-arc directed energy deposited Mg-Gd-Y-Zr alloy by tailoring aging procedures

Mg-Gd-Y-Zr alloy,as a typical magnesium rare-earth(Mg-RE)alloy,is gaining popularity in the advanced equipment manufacturing fields owing to its noticeable age-hardening properties and high specific strength.However,it is extremely challenging to prepare wrought components with large dimensions and complex shapes because of the poor room-temperature processability of Mg-Gd-Y-Zr alloy.Herein,we report a wire-arc directed energy deposited(DED)Mg-10.45Gd-2.27Y-0.52Zr(wt.%,GW102K)alloy with high RE content presenting a prominent combination of strength and ductility,realized by tailored nanoprecipitates through an optimized heat treatment procedure.Specifically,the solution-treated sample exhibits excellent ductility with an elongation(EL)of(14.6±0.1)%,while the aging-treated sample at 200°C for 58 h achieves an ultra-high ultimate tensile strength(UTS)of(371±1.5)MPa.Besides,the aging-treated sample at 250°C for 16 h attains a good strength-ductility synergy with a UTS of(316±2.1)MPa and a EL of(8.5±0.1)%.Particularly,the evolution mechanisms of precipitation response induced by various aging parameters and deformation behavior caused by nanoprecipitates type were also systematically revealed.The excellent ductility resulted from coordinating localized strains facilitated by active slip activity.And the ultra-high strength should be ascribed to the dense nano-β'hampering dislocation motion.Additionally,the shearable nano-β1 contributed to the good strength-ductility synergy.This work thus offers insightful understanding into the nanoprecipitates manipulation and performance tailoring for the wire-arc DED preparation of large-sized Mg-Gd-Y-Zr components with complex geometries.

A novel live attenuated vaccine candidate protects chickens against subtype B avian metapneumovirus

Avian metapneumovirus(aMPV) is a highly contagious pathogen that causes acute upper respiratory tract diseases in chickens and turkeys, resulting in serious economic losses. Subtype B aMPV has recently become the dominant epidemic strain in China. We developed an attenuated aMPV subtype B strain by serial passaging in Vero cells and evaluated its safety and efficacy as a vaccine candidate. The safety test showed that after the 30th passage, the LN16-A strain was fully attenuated, as clinical signs of infection and histological lesions were absent after inoculation.The LN16-A strain did not revert to a virulent strain after five serial passages in chickens. The genomic sequence of LN16-A differed from that of the parent wild-type LN16(wtLN16) strain and had nine amino acid mutations. In chickens, a single immunization with LN16-A induced robust humoral and cellular immune responses, including the abundant production of neutralizing antibodies, CD4^(+) T lymphocytes, and the Th1(IFN-γ) and Th2(IL-4 and IL-6)cytokines. We also confirmed that LN16-A provided 100% protection against subtype B aMPV and significantly reduced viral shedding and turbinate inflammation. Our findings suggest that the LN16-A strain is a promising live attenuated vaccine candidate that can prevent infection with subtype B aMPV.

Stability analysis of a liquid crystal elastomer self-oscillator under a linear temperature field

Self-oscillating systems abound in the natural world and offer substantial potential for applications in controllers,micro-motors,medical equipments,and so on.Currently,numerical methods have been widely utilized for obtaining the characteristics of self-oscillation including amplitude and frequency.However,numerical methods are burdened by intricate computations and limited precision,hindering comprehensive investigations into self-oscillating systems.In this paper,the stability of a liquid crystal elastomer fiber self-oscillating system under a linear temperature field is studied,and analytical solutions for the amplitude and frequency are determined.Initially,we establish the governing equations of self-oscillation,elucidate two motion regimes,and reveal the underlying mechanism.Subsequently,we conduct a stability analysis and employ a multi-scale method to obtain the analytical solutions for the amplitude and frequency.The results show agreement between the multi-scale and numerical methods.This research contributes to the examination of diverse self-oscillating systems and advances the theoretical analysis of self-oscillating systems rooted in active materials.

Research on the flow stability and noise reduction characteristics of quasi-periodic elastic support skin

To enhance flow stability and reduce hydrodynamic noise caused by fluctuating pressure,a quasiperiodic elastic support skin composed of flexible walls and elastic support elements is proposed for fluid noise reduction.The arrangement of the elastic support element is determined by the equivalent periodic distance and quasi-periodic coefficient.In this paper,a dynamic model of skin in a fluid environment is established.The influence of equivalent periodic distance and quasi-periodic coefficient on flow stability is investigated.The results suggest that arranging the elastic support elements in accordance with the quasi-periodic law can effectively enhance flow stability.Meanwhile,the hydrodynamic noise calculation results demonstrate that the skin exhibits excellent noise reduction performance,with reductions of 10 dB in the streamwise direction,11 dB in the spanwise direction,and 10 dB in the normal direction.The results also demonstrate that the stability analysis method can serve as a diagnostic tool for flow fields and guide the design of noise reduction structures.

MAPK9 as a therapeutic target:unveiling ferroptosis in localized prostate cancer progression

Background:Ferroptosis,a lipid peroxidation-mediated programmed cell death,is closely linked to tumor development,including prostate cancer(PCa).Despite established connections between ferroptosis and PCa,a comprehensive investigation is essential for understanding its impact on patient prognosis.Methods:A risk model incorporating four ferroptosis-related genes was developed and validated.Elevated risk scores correlated with an increased likelihood of biochemical recurrence(BCR),diminished immune infiltration,and adverse clinicopathological characteristics.To corroborate these results,we performed validation analyses utilizing datasets from both the Cancer Genome Atlas Cohort(TCGA)and the Gene Expression Synthesis Cohort(GEO).Moreover,we conducted further investigations into the pivotal gene identified in our model to explore its impact on tumor characteristics through cell proliferation and invasion assays,as well as animal studies conducted in vivo.Additionally,we conducted further experiments involving ferroptosis-related analysis to validate its association with ferroptosis.Results:The risk model demonstrated exceptional predictive capabilities for prognosis and therapeutic outcomes in PCa patients.Mitogen-activated protein kinase 9(MAPK9)emerged as a crucial gene within the model.In vivo and in vitro experiments explored MAPK9’s role in ferroptosis and its influence on tumor migration and proliferation.Conclusion:The findings provide a novel perspective for advancing ferroptosis exploration in PCa,bridging basic research and clinical applications.

多效并举建设化学实验中心,服务高质量实验教学

在多年的实践过程中,针对本科化学实验教学面临的种种挑战,郑州大学化学实验教学中心多效并举,形成了一系列特色鲜明的教学管理方法,有效服务了高质量化学实验教学工作的开展。本文介绍了郑州大学化学实验教学中心建设中的一些举措和取得的成效,希望能为高校化学实验教学工作和管理服务提供有益的参考借鉴。

Mechanism of gas pressure action during the initial failure of coal containing gas and its application for an outburst inoculation

Faced with the continuous occurrence of coal and gas outburst(hereinafter referred to as“outburst”)disasters,as a main controlling factor in the evolution process of an outburst,for gas pressure,it is still unclear about the phased characteristics of the coupling process with in situ stress,which induce coal damage and instability.Therefore,in the work based on the mining stress paths induced by typical outburst accidents,the gradual and sudden change of three-dimensional stress is taken as the background for the mechanical reconstruction of the disaster process.Then the true triaxial physical experiments are conducted on the damage and instability of coal containing gas under multiple stress paths.Finally,the response characterization between coal damage and gas pressure has been clarified,revealing the mechanism of action of gas pressure during the initial failure of coals.And the main controlling mechanism during the outburst process is elucidated in the coupling process of in situ stress with gas pressure.The results show that during the process of stress loading and unloading,the original gas pressure enters the processes of strengthening and weakening the action ability successively.And the strengthening effect continues to the period of large-scale destruction of coals.The mechanical process of gas pressure during the initial failure of coals can be divided into three stages:the enhancement of strengthening action ability,the decrease of strengthening action ability,and the weakening action ability.The entire process is implemented by changing the dominant action of in situ stress into the dominant action of gas pressure.The failure strength of coals is not only affected by its original mechanical strength,but also by the stress loading and unloading paths,showing a particularly significant effect.Three stages can be divided during outburst inoculation process.That is,firstly,the coals suffer from initial damage through the dominant action of in situ stress with synergy of gas pressure;secondly,the coals with spallation of structural division are generated through the dominant action of gas pressure with synergy of in situ stress,accompanied by further fragmentation;and finally,the fractured coals suffer from fragmentation and pulverization with the gas pressure action.Accordingly,the final broken coals are ejected out with the gas action,initiating an outburst.The research results can provide a new perspective for deepening the understanding of coal and gas outburst mechanism,laying a theoretical foundation for the innovation of outburst prevention and control technologies.

CK5/6-positive,P63-positive lymphoepithelioma-like hepatocellular carcinoma:A case report and literature review

BACKGROUND Lymphoepithelioma-like carcinoma(LELC),a rare and unique variant of liver cancer,can be divided into lymphoepithelioma-like hepatocellular carcinoma and lymphoepithelioma-like intrahepatic cholangiocarcinoma.Dense lymphocytic infiltration is its characteristic pathological feature.In recent years,the number of reported cases of this type has increased each year.Studies have shown that lymphoepithelioma-like cholangiocarcinoma occurs more frequently in Asian women;LELC is associated with Epstein–Barr virus infection of liver cells of epithelial origin.Existing research shows that the prognosis of this tumour is good.CASE SUMMARY A 38-year-old female patient was hospitalized after 3 mo of abdominal pain and nausea.She had been infected with hepatitis B virus more than 10 years prior.The patient was hospitalized on January 21,2022.Magnetic resonance imaging showed a 36 mm×28 mm mass under the envelope of the left inner lobe of the liver.No metastasis of lymph nodes or other organs was observed.After left hemihepatectomy,biopsy and immunohistochemistry yielded a final diagnosis of lymphoepithelial hepatocellular carcinoma.After 12 mo of outpatient follow-up and chemotherapy,no tumour metastases were found on the latest computed tomography examination.CONCLUSION Herein,the patient was treated surgically and then followed up as an outpatient for 12 mo.This case will further expand our overall knowledge of the diagnosis and treatment of this rare tumor.

Preoperative and postoperative complications as risk factors for delayed gastric emptying following pancreaticoduodenectomy: A single-center retrospective study

BACKGROUND Mortality rates after pancreaticoduodenectomy(PD)have significantly decreased in specialized centers.However,postoperative morbidity,particularly delayed gastric emptying(DGE),remains the most frequent complication following PD.AIM To identify risk factors associated with DGE after the PD procedure.METHODS In this retrospective,cross-sectional study,clinical data were collected from 114 patients who underwent PD between January 2015 and June 2018.Demographic factors,pre-and perioperative characteristics,and surgical complications were assessed.Univariate and multivariate analyses were performed to identify risk factors for post-PD DGE.RESULTS The study included 66 males(57.9%)and 48 females(42.1%),aged 33-83 years(mean:62.5),with a male-to-female ratio of approximately 1.4:1.There were 63 cases(55.3%)of PD and 51 cases(44.7%)of pylorus-preserving pancreatoduodenectomy.Among the 114 patients who underwent PD,33(28.9%)developed postoperative DGE.Univariate analysis revealed significant differences in four of the 14 clinical indexes observed:pylorus preservation,retrocolonic anastomosis,postoperative abdominal complications,and early postoperative albumin(ALB).Logistic regression analysis further identified postoperative abdominal complic-ations[odds ratio(OR)=4.768,P=0.002],preoperative systemic diseases(OR=2.516,P=0.049),and early postoperative ALB(OR=1.195,P=0.003)as significant risk factors.CONCLUSION Postoperative severe abdominal complications,preoperative systemic diseases,and early postoperative ALB are identified as risk factors for post-PD DGE.

Influence of Solar Activity on Precise Orbit Prediction of LEO Satellites

The perturbations of low earth orbit(LEO)satellites operating in the orbit of 300~2000 km are complicated.In particular,the atmospheric drag force and solar radiation pressure force change rapidly over a short period of time due to solar activities.Using spaceborne global positioning system(GPS)data of the CHAMP,GRACE and SWARM satellites from 2002 to 2020,this paper studies in depth the influence of solar activity on LEO satellites’precise orbit prediction by performing a series of orbit prediction experiments.The quality of GPS data is more susceptible to being influenced by solar activity during years when this activity is high and the changes in dynamic parameters are consistent with those of solar activity.The effects of solar activity on LEO orbit prediction accuracy are analyzed by comparing the predicted orbits with the precise ones.During years of high solar activity,the average root-mean-squares prediction errors at 10,20,and 30 minutes are 0.15,0.20,and 0.26 m,respectively,which are larger than the corresponding values in low-solar-activity years by 59%,63%,and 68%,respectively.These results demonstrate that solar activity has a great influence on the orbit prediction accuracy,especially during high-solar-activity years.We should strengthen the real-time monitoring of solar activity and geomagnetic activity,and formulate corresponding orbit prediction strategies for the active solar period.

The profile of sound speed and dissolved oxygen in the polymetallic nodules depositional area in the Western Pacific

With the consumption of terrestrial metal resources,the exploitation of deep-sea polymetallic nodule minerals has been widely concerned around the world.Therefore,the environmental impact of deep-sea polymetallic nodule mining cannot be ignored.However,duo to the lacks in stable and safe deep-sea(the depth>1000 m)vertical profile observation systems and consequently in long-term in-situ observation data,the sound speed and dissolved oxygen and the other water environment factors in the deposition areas of polymetallic nodules remains poorly understood.In this study,a deep-sea in-situ observation system was designed and deployed,and the water environment data of the polymetallic nodule deposition area were collected and analyzed.Result shows that the dissolved oxygen in the depth of 0–600 m was mainly affected by biological factors,while that in the area deeper than 600 m was affected by physical factors.The sound speed in the water body was mainly affected by temperature and pressure.At depths below 840 m,the sound speed is mainly controlled by temperature,and at depths between 840 m and 5700 m,the sound speed is mainly controlled by pressure.The correlations of sound speed vs.pressure and vs.temperature were regressed into equation.The resuspension of sediments rich in various metals may result in the reduction of dissolved oxygen and the improvement of redox potential.This environmental impact caused by a single sediment resuspension could last for 24 h or more.These findings enrich the understanding of the background value of the water environment in the polymetallic nodule deposition area.

The soybean GmPUB21-interacting protein GmDi19-5 responds to drought and salinity stresses via an ABA-dependent pathway

Drought-induced protein 19(Di19) is a Cys2/His2 zinc-finger protein that functions in plant growth and development and in tolerance to abiotic stresses.Gm PUB21,an E3 ubiquitin ligase,negatively regulates drought and salinity response in soybean.We identified potential interaction target proteins of Gm PUB21by yeast two-hybrid c DNA library screening,Gm Di19-5 as a candidate.Bimolecular fluorescence complementation and glutathionine-S-transferase pull-down assays confirmed the interaction between Gm Di19-5 and Gm PUB21.Gm Di19-5 was induced by Na Cl,drought,and abscisic acid(ABA) treatments.Gm Di19-5 was expressed in the cytoplasm and nucleus.Gm Di19-5 overexpression conferred hypersensitivity to drought and high salinity,whereas Gm Di19-5 silencing increased drought and salinity tolerance.Transcripts of ABA-and stress response-associated genes including Gm RAB18 and Gm DREB2A were downregulated in Gm Di19-5-overexpressing plants under drought and salinity stresses.ABA decreased the protein level of Gm Di19-5 in vivo,whereas Gm PUB21 increased the decrease of Gm Di19-5 after exogenous ABA application.The accumulation of Gm PUB21 was also inhibited by Gm Di19-5.We conclude that Gm PUB21 and Gm Di19-5 collaborate to regulate drought and salinity tolerance via an ABA-dependent pathway.

End-to-End Joint Multi-Object Detection and Tracking for Intelligent Transportation Systems

Environment perception is one of the most critical technology of intelligent transportation systems(ITS).Motion interaction between multiple vehicles in ITS makes it important to perform multi-object tracking(MOT).However,most existing MOT algorithms follow the tracking-by-detection framework,which separates detection and tracking into two independent segments and limit the global efciency.Recently,a few algorithms have combined feature extraction into one network;however,the tracking portion continues to rely on data association,and requires com‑plex post-processing for life cycle management.Those methods do not combine detection and tracking efciently.This paper presents a novel network to realize joint multi-object detection and tracking in an end-to-end manner for ITS,named as global correlation network(GCNet).Unlike most object detection methods,GCNet introduces a global correlation layer for regression of absolute size and coordinates of bounding boxes,instead of ofsetting predictions.The pipeline of detection and tracking in GCNet is conceptually simple,and does not require compli‑cated tracking strategies such as non-maximum suppression and data association.GCNet was evaluated on a multivehicle tracking dataset,UA-DETRAC,demonstrating promising performance compared to state-of-the-art detectors and trackers.

Application of shifted lattice model to 3D compressible lattice Boltzmann method

An additional potential energy distribution function is introduced on the basis of previous D3Q25 model,and the equilibrium distribution function of D3Q25 is obtained by spherical function.A novel three-dimensional(3D)shifted lattice model is proposed,therefore a shifted lattice model is introduced into D3Q25.Under the finite volume scheme,several typical compressible calculation examples are used to verify whether the numerical stability of the D3Q25 model can be improved by adding the shifted lattice model.The simulation results show that the numerical stability is indeed improved after adding the shifted lattice model.

“过程全面精准”考核在化工原理实验课程中改革与探索

针对化工原理实验教学考核方式单一和学生学习兴趣低等难题,在教学中引入虚拟仿真和“互联网+”技术,构建全新“线上线下混合式”教学模式,实行闯关式学习方式,将教学大纲考核点细化,分步骤给分,部分实验实行分类教学,根据权重赋分,形成全面考核体系。线下实验实行线上控制给分,实验过程中学生可以随时查看成绩,调整学习状态。建立网络机器人答疑平台,在线答疑,真正实现全过程教学,提高化工原理实验教学质量,助力于中国高等教育的创新改革。

NiFe-MOF和氮氧自由基协同增强甾醇电催化氧化

传统甾醇中间体氧化采用重金属铬作为氧化剂,存在毒性大和环境污染等问题。电催化氧化(ECO)以其高效、环保、可控的优点备受青睐,被认为是一种可替代传统工艺的方法。然而,目前ECO面临低电流密度和低时空产率的挑战。本研究采用一步溶剂热法在石墨毡上制备自支撑NiFe-MOF纳米片电催化剂,并耦合NiFe-MOF与氮氧自由基(4-乙酰氨-2,2,6,6-四甲基哌啶-1-氧)协同电催化策略以提高ECO性能。研究发现碱性电解液可重构NiFe-MOF催化剂,从而提高催化活性。此外,连续流动强化传质,成功实现以100 mA·cm^(-2)的大电流密度对19-羟基-4-雄甾烯-3,17-二酮(1a)的选择性电催化氧化,且选择性高达98%,时空产率可达15.88 kg·m^(-3)·h^(-1),是间歇电反应器的35倍。寿命测试发现经10次循环反应后,NiFe-MOF/ACT协同体系对ECO仍具有较高的转化率。通过增大NiFe-MOF面积,将其组装至连续流动式电反应器并进行ECO恒电流电解,可达到12.99 kg·m^(-3)·h^(-1)的时空产率。该工作提出一种NiFe-MOF/ACT协同电催化氧化策略,为实现甾醇选择性氧化提供新的见解。

水杨醛席夫碱的合成与聚集诱导发光(AIE)性能研究综合实验的课程思政设计

水杨醛席夫碱的合成与聚集诱导发光(AIE)性能研究是郑州大学化学学院针对化学专业本科学生设计并开设的一个综合实验项目,已经开设了5个学年,经过不断的改进和完善,形成了具有代表性的实验教学课程思政案例。案例以AIE这一由中国人原创的前沿科学理论为载体,通过AIE现象发现过程的学习、在不同条件下分组亲身实践AIE的合成操作、观察AIE的发光性能等过程,将AIE现象与国家科技发展、社会需求相联系,把“民族自豪感”“科研创新精神”“社会担当精神”“辩证唯物主义思维”等课程思政元素融入到实验教学中,让学生在提高“发现问题、分析问题、解决问题”综合能力的同时,充分了解荧光材料在国民经济和社会发展中的重要作用,提升学生的民族自尊心和自信心,坚定“见人所未见,思人所未思”的科研理念,激发服务国家发展的热情。

低维钙钛矿太阳能电池的制备与光电性能研究——推荐一个综合化学实验

低维钙钛矿太阳能电池(Low-Dimensional Perovskite Solar Cells,LD PSCs)是一种稳定性好、疏水性强的新型钙钛矿光伏器件,在新能源领域受到了广泛的关注。本实验以领域内的前沿进展为出发点,提供丁胺(Butylammonium,BA)离子、半胱氨酸(2-氨基-3-巯基丙酸,Cysteine,Cys)离子作为有机间隔阳离子,合成了低维钙钛矿晶体并制备出以(BA)2(MA)n-1PbnI3n+1或(Cys)2(MA)n-1PbnI3n+1为活性层的钙钛矿太阳能电池,并通过X射线衍射检测、紫外-可见吸收检测等手段对产品进行表征,之后测定了钙钛矿器件的能量转换效率。本实验难度适中,涉及光伏器件的制备与表征,旨在激励本科生对前沿光电研究产生兴趣、培养其科研能力。

Growth hormone promotes the reconstruction of injured axons in the hypothalamo-neurohypophyseal system

Previous studies have shown that growth hormone can regulate hypothalamic energy metabolism, stress, and hormone release. Therefore, growth hormone has great potential for treating hypothalamic injury. In this study, we established a specific hypothalamic axon injury model by inducing hypothalamic pituitary stalk electric lesions in male mice. We then treated mice by intraperitoneal administration of growth hormone. Our results showed that growth hormone increased the expression of insulin-like growth factor 1 and its receptors, and promoted the survival of hypothalamic neurons, axonal regeneration, and vascular reconstruction from the median eminence through the posterior pituitary. Altogether, this alleviated hypothalamic injury-caused central diabetes insipidus and anxiety. These results suggest that growth hormone can promote axonal reconstruction after hypothalamic injury by regulating the growth hormone-insulin-like growth factor 1 axis.

Biomimetic 3D printing of composite structures with decreased cracking

The development of tissue engineering and regeneration research has created new platforms for bone transplantation.However,the preparation of scaffolds with good fiber integrity is challenging,because scaffolds prepared by traditional printing methods are prone to fiber cracking during solvent evaporation.Human skin has an excellent natural heat-management system,which helps to maintain a constant body temperature through perspiration or blood-vessel constriction.In this work,an electrohydrodynamic-jet 3D-printing method inspired by the thermal-management system of skin was developed.In this system,the evaporation of solvent in the printed fibers can be adjusted using the temperature-change rate of the substrate to prepare 3D structures with good structural integrity.To investigate the solvent evaporation and the interlayer bonding of the fibers,finite-element analysis simulations of a three-layer microscale structure were carried out.The results show that the solvent-evaporation path is from bottom to top,and the strain in the printed structure becomes smaller with a smaller temperaturechange rate.Experimental results verified the accuracy of these simulation results,and a variety of complex 3D structures with high aspect ratios were printed.Microscale cracks were reduced to the nanoscale by adjusting the temperature-change rate from 2.5 to 0.5℃s-1.Optimized process parameters were selected to prepare a tissue engineering scaffold with high integrity.It was confirmed that this printed scaffold had good biocompatibility and could be used for bone-tissue regeneration.This simple and flexible 3D-printing method can also help with the preparation of a wide range of micro-and nanostructured sensors and actuators.