Interlayer heat accumulation(IHA)is major challenge in the laser powder bed fusion(LPBF)process,as it exacerbates the instability of melt pools,and compromises the quality of the as-built samples.Infrared radiation mo...Interlayer heat accumulation(IHA)is major challenge in the laser powder bed fusion(LPBF)process,as it exacerbates the instability of melt pools,and compromises the quality of the as-built samples.Infrared radiation monitoring is an effective method for exploring IHA.Based on the defined sequence features of interlayer infrared radiation intensity(IIRI),this study established a gated recurrent unit(GRU)neural network model for predicting IIRI in formed samples using machine learning to mitigate the IHA.The model trained on 316 L alloys achieved precise prediction results when transferred to the DZ125 superalloy,effectively managing various emergencies in the LPBF process.The truncated pyramid components were fabricated through parameter optimization based on IIRI prediction results.Compared with the non-optimized components,the CT results demonstrated a significant reduction in internal voids,with the relative density increasing from 91.6% to 98.5%.Additionally,surface roughness(Ra)decreased from 32.58μm to 19.91μm,while residual stress on the top surface was reduced from 169.21 MPa to 102.37 MPa.展开更多
Triply periodic minimal surfaces(TPMS)are structures with smooth surfaces and excellent energy absorption properties.Combining new functional materials,such as shape memory alloys,with TPMS structures provides a novel...Triply periodic minimal surfaces(TPMS)are structures with smooth surfaces and excellent energy absorption properties.Combining new functional materials,such as shape memory alloys,with TPMS structures provides a novel and promising research field.In this study,three TPMS structures(Gyroid,Diamond,and Primitive)of Cu-11.85Al-3.2Mn-0.1Ti alloy were printed by laser powder bed fusion,which is favorable for the fabrication of complex structures.The manufacturing fidelity,mechanical response,and superelastic properties of the three structures were investigated.Stress distributions in the three structures during compression were analyzed by finite element(FE)simulation.The three structures were equipped with high-quality,glossy surfaces and uniform pores.However,due to powder adhesion and forming steps,there were volumetric errors and dimensional deviations between the samples and the CAD models.The errors were within 1.6%for the Gyroid and Diamond structures.The dimensional deviations at the nodes in the three structures were less than 0.09 mm.The microstructures of all structures wereβ1´martensite,consistent with the cubic sample.Experimental results of compression showed that the structures underwent a layer-by-layer compression failure mode,and the Primitive structures exhibited a more pronounced oscillatory process.The Diamond structures showed the highest first fracture stress and strain of 164.67 MPa and 13.89%,respectively.It also possessed the lowest yield strength(61.97 MPa)and the best energy absorption properties(7.6 MJ/m3).Through the deformation analysis,the Gyroid and Diamond structures were found to fracture at a 45°direction,while the Primitive structures fractured horizontally.These findings were consistent with the results obtained from the FE simulation,which showed equivalent stress distributions.After applying various pre-strains,the Diamond structures displayed the highest superelastic strain of up to 3.53%.The superelastic recovery of all samples ranged from 63.5%to 71.5%.展开更多
WE43 is a high-strength magnesium alloy containing rare-earth elements such as Y,Gd and Nd.Nevertheless,how to further obtain the balance of strength and ductility,as well as the manufacture of complex structures is s...WE43 is a high-strength magnesium alloy containing rare-earth elements such as Y,Gd and Nd.Nevertheless,how to further obtain the balance of strength and ductility,as well as the manufacture of complex structures is still a dilemma for its engineering application.In this study,WE43 alloy samples withfine microstructures,high densification and excellent mechanical properties were successfully prepared by laser powder bed fusion(LPBF)additive manufacturing.The optimal process window was established,and the formation mechanisms of three types of porosity defects were revealed,namely lack-of-fusion pores,meltfluctuation-induced pores,and keyhole-induced pores.With the combined process of laser power of 200 W and scanning speed of 600 mm/s,samples with a high density of 99.89%were obtained.Furthermore,periodic heterogeneous microstructure was prepared along the build direction,i.e.,fine grains(∼4.1μm)at melt pool boundaries and coarse grain(∼23.6μm)inside melt pool.This was mainly due to the preferential precipitation of Zr and Mg_(3)(Gd,Nd)nano-precipitates at the melt pool boundaries providing nucleation sites for the grains.This special feature could provide an extra hetero-deformation induced(HDI)strengthening and retard fracture.The optimal tensile yield strength,ultimate tensile strength and elongation at break were 276±1 MPa,292±1 MPa and 6.1±0.2%,respectively.The obtained tensile properties were superior to those of other magnesium alloys and those fabricated by other processes.The solid solution strengthening(∼24.5%),grain boundary strengthening(∼14.4%)and HDI strengthening(∼32.2%)were the main sources of high yield strength.This work provides a guidance on studying the pore defect suppression and strengthening mechanisms of WE43 alloy and other magnesium alloys produced by LPBF.展开更多
In this editorial,we examined a recent article in the World Journal of Gastroenterology that focused on sepsis-associated liver injury(SLI)and its treatment.SLI is a serious complication of sepsis,primarily caused by ...In this editorial,we examined a recent article in the World Journal of Gastroenterology that focused on sepsis-associated liver injury(SLI)and its treatment.SLI is a serious complication of sepsis,primarily caused by microcirculatory disturbances,the gut-liver axis,and inflammatory responses.Specific treatment recommendations for SLI are lacking.The gut-liver axis represents a potential therapeutic target,with metformin showing promise in modulating the gut microbiome and enhancing intestinal barrier function.Although immunomodulatory therapies are being explored,anti-tumor necrosis factor agents and interleukin-1 receptor antagonists have not demonstrated significant clinical benefits.Statins may reduce liver inflammation and prevent injury in sepsis,but their clinical application is limited.Reduced D-related human leucocyte antigen expression on monocytes and lymphocytes suggests immune suppression in patients,indicating that corticosteroids could reverse clinical deterioration in severe infections and address adrenal cortical insufficiency.Current large-scale studies on glucocorticoid therapy for sepsis have yielded mixed results,likely due to inadequate assessment of the immune status of the host.Future research should prioritize the development of personalized immunotherapy tailored to patients’immune profiles,focusing on identifying novel indicators of immune status and advancing immunomodulatory targets and therapeutics for septic patients.展开更多
Additive manufacturing(AM)technology enables the creation of a wide variety of assemblies and complex shapes from three-dimensional model data in a bottom-up,layer-by-layer manner.Therefore,AM has revolutionized the m...Additive manufacturing(AM)technology enables the creation of a wide variety of assemblies and complex shapes from three-dimensional model data in a bottom-up,layer-by-layer manner.Therefore,AM has revolutionized the modern manufacturing industry,attracting increasing interest from both academic and industrial fields.The Rapid Manufacturing Center(RMC)of the School of Materials Science and Engineering at the Huazhong Univer-sity of Science and Technology(HUST),one of the earliest and most powerful AM research teams in China,has been engaged in AM research since 1991.Aiming to address the“stuck neck”problems of specific high-strength products for AM,the RMC has conducted full-chain research in the aspects of special materials,processes,equip-ment,and applications for AM.Moreover,it has formed a multi-disciplinary research team over the past three decades.Relevant research achievements in the AM field include winning five national awards,more than ten first prizes,and more than ten second prizes at the provincial and ministerial levels.The RMC was complimented as“the world’s most influential organization in the laser AM field in 2018”by Virtual and Physical Prototyping(an international authoritative magazine of AM).Moreover,their industrialization achievements were evaluated as“having affected countries such as Singapore,South Korea,and the United States”by an international author-itative Wohlers Report on AM.In this study,we first summarize the representative research achievements of the RMC in the AM field.These include the preparation and processing technology of high-performance polymeric,metallic,and ceramic materials for AM;advanced processing technology and software/equipment for AM;and typical AM-fabricated products and their applications.Further,we discuss the latest research achievements in cutting-edge 4D printing in terms of feedstock selection,printing processes,induction strategies,and potential ap-plications.Finally,we provide insights into the future directions of AM technology development:(ⅰ)Evolving from three-dimensional printing to multi-dimensional printing,(ⅱ)transitioning from plane slicing to curved surface slicing to woven slicing,(ⅲ)enhancing efficient formation from dot-line-sheet-volume printing,(ⅳ)shifting from single material to multi-materials AM,(ⅴ)advancing from the multiscale direction of macroscopic-mesoscopic-microscopic structures,(ⅵ)integrating material preparation with forming integration,(ⅶ)expanding from small batch to large batch.展开更多
Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)holds significant promise for sustainable energy conversion,with cobalt phthalocyanine(CoPc)emerging as a notable catalyst due to its high CO selectivity.However,CoPc...Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)holds significant promise for sustainable energy conversion,with cobalt phthalocyanine(CoPc)emerging as a notable catalyst due to its high CO selectivity.However,CoPc's efficacy is hindered by its limited ability to provide sufficient proton for the protonation process,particularly at industrial current densities.Herein,we introduce defect-engineered carbon nanotubes(d-CNT)to augment proton feeding for CO_(2)RR over CoPc,achieved by expediting water dissociation.Our kinetic measurements and in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy reveal d-CNT significantly enhances proton feeding,thereby facilitating CO_(2)activation to*COOH in CoPc.Density functional theory calculations corroborate these findings,illustrating that d-CNT decreases the barrier to water dissociation.Consequently,the CoPc/d-CNT mixture demonstrates robust performance,achieving 500 mA cm^(-2)for CO_(2)RR with CO selectivity exceeding 96%.Notably,CoPc/d-CNT remains stability for a duration of 20 h under a substantial current density of 150 mA cm^(-2).The study broadens the scope of practical applications for molecular catalysts in CO_(2)RR,marking a significant step towards sustainable energy conversion.展开更多
碱性析氢反应(HER)可将间歇性可再生能源转化为可存储的清洁能源,因而备受关注.然而,水解离速度缓慢以及H中间体(*H)吸附和解吸困难限制了碱性HER的进一步发展.目前,针对碱性电解水解离缓慢问题,通常采用调整电催化剂结构降低水分解热...碱性析氢反应(HER)可将间歇性可再生能源转化为可存储的清洁能源,因而备受关注.然而,水解离速度缓慢以及H中间体(*H)吸附和解吸困难限制了碱性HER的进一步发展.目前,针对碱性电解水解离缓慢问题,通常采用调整电催化剂结构降低水分解热动力学能垒,以及改变三相界面微环境加速中间产物的扩散等方法来促进水分解进行.此外,可以通过调控活性位点电子结构来优化*H的吸脱附.但是采用单一的策略很难同时促进H_(2)O的解离和*H的吸脱附,难以获得令人满意的碱性HER性能.因此,探索一种能同时促进H_(2)O的解离和*H的吸脱附协同策略对提升碱性HER的性能至关重要.本文提出了一种协同策略,通过构建高曲率二硫化钴纳米针(CoS_(2)NNs)和原子级铜(Cu)的掺杂分别实现诱导纳米尺度的局域电场和原子尺度的电子局域化,从而促进碱性HER的H_(2)O解离和*H吸脱附.首先,采用有限元法模拟和密度泛函理论计算,从理论上分别证实了纳米尺度局域电场可以加速H_(2)O解离以及原子尺度电子局域化可以促进*H吸附.受理论计算结果启发,通过一步水热法和原位硫化相结合的方法制备了高曲率的Cu掺杂CoS_(2)纳米针(Cu-CoS_(2)NNs).采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)和四探针测试等技术进行表征,研究了Cu-CoS_(2)NNs的形貌、物相结构、化学组成和导电性.结果表明,在Cu原子引入后,Cu-CoS_(2)NNs依然保持着高曲率的纳米针结构,证明了Cu在CoS_(2)NNs中的原子分散状态.相较于低曲率的Cu掺杂CoS_(2)纳米线(Cu-CoS_(2)NWs),Cu-CoS_(2)NNs只存在形貌上的区别,二者的化学组成和比例均非常接近.同时,上述材料都具有很强的导电性,且电导率基本相同,这与有限元模拟结果一致.原位衰减全反射红外光谱和电响应测试结果表明,Cu-CoS_(2)NNs具有较好的解离H_(2)O和吸附*H的能力.在1 mol L^(-1)KOH溶液和10 mA cm^(-2)电流密度下,该催化剂的析氢过电位仅为64 mV,展现出较好的电化学析氢性能.催化剂还表现出非常好的碱性析氢稳定性,在标准氢电势(RHE)-0.18 V下,可在100 mA cm^(-2)电流密度下稳定工作达100 h.综上所述,本文通过诱导局域电场和电子局域化构建了一种协同策略,所制备的Cu-CoS_(2)NNs表现出很好的催化碱性HER性能和应用前景,为碱性HER电催化剂的理性设计提供了一定的参考.展开更多
This paper presents a comprehensive study conducted to optimize the selective laser melting(SLM)parameters and subsequent heat-treatment temperatures for near-α high-temperature titanium alloy Ti-6 Al-2 Zr-1 Mo-1 V(T...This paper presents a comprehensive study conducted to optimize the selective laser melting(SLM)parameters and subsequent heat-treatment temperatures for near-α high-temperature titanium alloy Ti-6 Al-2 Zr-1 Mo-1 V(TA15),which is widely used in the aerospace industry.Based on the surface morphology and relative density analysis,the optimized process parameters were:laser power from 230 W to 380 W,scan speed from 675 mm/s to 800 mm/s,scan spacing of 0.12 mm,and layer thickness of0.03 mm.The effects of the laser power and the layer thickness on the phase constitutions,microstructure features,as well as room-temperature and high-temperature(500℃) tensile properties,were then studied to obtain an in-depth understanding of SLM-built TA15.Six typical temperatures(650,750,850,950,1000 and 1100℃) covering three representative temperature ranges,i.e.,martensite partial decomposition temperature range,martensite complete decomposition temperature range and above βtransus temperature,were subsequently selected as heat-treatment temperatures.The heat treatmentmicrostructure-mechanical property relationships of SLM-built TA15 were elucidated in detail.These results provide valuable information on the development of SLM-built TA15 alloy for industrial applications,and these findings are also beneficial to additive manufacturing of other near-α Ti alloys with desirable high-temperature properties.展开更多
The Shima yield criterion used in finite element analysis for nickel-based superalloy powder compact during hot isostatic pressing(HIP) was modified through uniaxial compression experiments. The influence of cylindric...The Shima yield criterion used in finite element analysis for nickel-based superalloy powder compact during hot isostatic pressing(HIP) was modified through uniaxial compression experiments. The influence of cylindrical capsule characteristics on FGH4096M superalloy powder compact deformation and densification behavior during HIP was investigated through simulations and experiments. Results revealed the simulation shrinkage prediction fitted well with the experimental shrinkage including a maximum shrinkage error of 1.5%. It was shown that the axial shrinkage was 1.7% higher than radial shrinkage for a cylindrical capsule with the size of ∮50 mm × 100 mm due to the force arm difference along the axial and radial direction of the capsule. The stress deviated from the isostatic state in the capsule led to the uneven shrinkage and non-uniform densification of the powder compact. The ratio of the maximum radial displacement to axial displacement increased from0.47 to 0.75 with the capsule thickness increasing from 2 to 4 mm. The pressure transmission is related to the capsule thickness, the capsule material performance, and physical parameters in the HIP process.展开更多
Rheumatoid arthritis(RA),as a chronic autoimmune disease,damages the bone and cartilage of patients,and even leads to disability.Therefore,the diagnosis and treatment of RA is particularly important.However,due to the...Rheumatoid arthritis(RA),as a chronic autoimmune disease,damages the bone and cartilage of patients,and even leads to disability.Therefore,the diagnosis and treatment of RA is particularly important.However,due to the complexity of RA,it is difficult to make effective early diagnosis of RA,which is detrimental to RA treatment.Besides,long-term intake of anti-RA drugs can also cause damage to patients' organs.The emergence of nanotechnology provides the new train of thoughts for the diagnosis and treatment of RA.And the combination of diagnosis and therapy is an ideal method to solve the problem of disease management of RA patients.In this review,we summarize the mechanism and microenvironment of RA,discuss the commonly used diagnostic techniques and therapeutic drugs for RA,and review their advantages and disadvantages.New nanotherapy strategies such as drug-carrying nanoparticles,PTT,PDT are listed,and their applications in RA treatment are also summarized.In addition,multimodal imaging,combined therapy and responsive diagnosis and treatment are also summarized as important contents.At last,we also review typical nanocarriers that can be used in the integration of diagnosis and therapy,and discussed their potential applications in RA theranostics.展开更多
A dermatan sulfate （DS） repeating disaccharide analog, β-L-idopyranosiduronate-（1→3）-2-amino-2- deoxy-4,6-di-O-sulfo-β-D-galactopyranoside, has been convergently synthesized and successfully applied to prepare ...A dermatan sulfate （DS） repeating disaccharide analog, β-L-idopyranosiduronate-（1→3）-2-amino-2- deoxy-4,6-di-O-sulfo-β-D-galactopyranoside, has been convergently synthesized and successfully applied to prepare the GAG-functionalized gold glyconanoparticle. This new material exhibited good anti-inflammatory activity which was comparable to that of the drug ibuprofen incarrageenan-induced paw edema in a rat model.展开更多
This paper systematically investigated the effect of solution and artificial aging heat treatments on the microstructural evolution and mechanical properties of TiB/Ti-6Al-4V composites in situ fabricated by selective...This paper systematically investigated the effect of solution and artificial aging heat treatments on the microstructural evolution and mechanical properties of TiB/Ti-6Al-4V composites in situ fabricated by selective laser melting.The results showed that the fully martensite microstructure with TiB clusters of the as-built samples was transformed into lamellarα+βmicrostructure with TiB strips after solution heat treatment.With increasing the temperature,theαlaths and TiB particles coarsened and theβvolume fraction increased.After aging heat treatment,βvolume fraction decreased and TiB had no obvious changes.A superior combination of the yield strength of(1146.8±28.2)MPa and even higher plasticity and ultimate compressive strength((1680.1±18.3)MPa)than the as-built ones was obtained by solution heat treatment at 1000℃+water quenching and aging at 600℃for 6 hþair cooling.展开更多
Radical prostatectomy （RP） has been a widely accepted and standard treat-ment for clinically localized and locally advanced prostate cancer. However, effective clinical management of RP patient remains being challen...Radical prostatectomy （RP） has been a widely accepted and standard treat-ment for clinically localized and locally advanced prostate cancer. However, effective clinical management of RP patient remains being challenged, given that conventional prognostic factors, including Gleason score, pT stage, surgical margin status and presurgery serum prostatespecific antigen （PSA）,展开更多
C-3-Functionalized steroids represent a pivotal class of molecules with diverse and significant biological functions.However,the reliable chemical synthesis of these compounds is frequently impeded by sub-strate sensi...C-3-Functionalized steroids represent a pivotal class of molecules with diverse and significant biological functions.However,the reliable chemical synthesis of these compounds is frequently impeded by sub-strate sensitivity and the propensity for i-steroid rearrangement of steroidal cations.Herein,we dis-close an efficient Sc(OTf)(_3)-catalyzed steroidation reaction that utilizes readily available steroidal tri-chloroacetimidates as donors.We have explored a broad spectrum of steroidal donors and acceptor substrates,including biomolecules such as sugars,steroids,amino acids,terpenoids,dye molecules,and small-molecule drugs,all of which possess multiple intricate functionalities.This reaction has been dem-onstrated to generate novel steroid chimeras with excellent regio-and diastereocontrol within 1 h under mild conditions.We have integrated a series of experimental investigations with density functional theory calculations to elucidate the reaction mechanism.Our findings reveal a controlled retro-i-steroid rearrangement of the kinetically favored and acid-activable C-6 i-steroid intermediates cata-lyzed by an in-situ generated protonic acid catalyst.展开更多
Zeaxanthin,an oxygenated carotenoid derivative with potent antioxidative properties,is produced by many organism taxa.Flavobacteriaceae are widely distributed in marine environments;however,the zeaxanthin biosynthesis...Zeaxanthin,an oxygenated carotenoid derivative with potent antioxidative properties,is produced by many organism taxa.Flavobacteriaceae are widely distributed in marine environments;however,the zeaxanthin biosynthesis property in this family remains incompletely explored.Here,we characterized zeaxanthin production by marine Flavobacteriaceae strains and elucidated underlying molecular mechanisms.Eight Flavobacteriaceae strains were isolated from the phycosphere of various dinoflagellates.Analyses of the zeaxanthin production in these strains revealed yields ranging from 5 to 3289μg/g of dry cell weight.Genomic and molecular biology analyses revealed the biosynthesized zeaxanthin through the mevalonate(MVA)pathway diverging from the 2-C-methyl-d-erythritol-4-phosphate(MEP)pathway commonly observed in most Gram-negative bacteria.Furthermore,comprehensive genome analyses of 322 culturable marine Flavobacteriale strains indicated that the majority of Flavobacteriaceae members possess the potential to synthesize zeaxanthin using precursors derived from the MVA pathway.These data provide insight into the zeaxanthin biosynthesis property in marine Flavobacteriaceae strains,highlighting their ecological and biotechnological relevance.展开更多
In order to effectively utilize the dielectric response characteristics of transformers to diagnose the insulation state,this paper proposes a two-level hybrid optimization method for analyzing time-domain dielectric ...In order to effectively utilize the dielectric response characteristics of transformers to diagnose the insulation state,this paper proposes a two-level hybrid optimization method for analyzing time-domain dielectric response characteristics.The optimization algorithm is based on the combined statistical indicators(CSI)and random forest(RF)theory.The initial feature space set is formed with 23 time-domain characteristics.In the first-level stage,statistical indices correlation,distance,and information indicators are integrated to assess the synthesis score of the characteristics,while highly redundant and lowclass discrimination characteristics are eliminated from the initial space set.In the second-level stage,the Random Forest based outside bagging data theory is introduced to evaluate the least important characteristics,and the characteristics with low importance indices are excluded to obtain the final optimal feature space set.The proposed method is carried out on 82 sets of data from actual dielectric response tests on oil-paper insulation transformers.Finally,the final optimal feature space set,along with several other data sets,is tested via different diagnosis methods.The results show that the optimal feature space set obtained via the proposed method outperforms other feature space sets in terms of better adaptability and diagnosis accuracy.展开更多
Repairing large-area soft tissue defects caused by traumas is a major surgical challenge.Developing multifunctional scaffolds with suitable scalability and favorable cellular response is crucial for soft tissue regene...Repairing large-area soft tissue defects caused by traumas is a major surgical challenge.Developing multifunctional scaffolds with suitable scalability and favorable cellular response is crucial for soft tissue regeneration.In this study,we developed an orthogonally woven three-dimensional(3D)nanofiber scaffold combining electrospinning,weaving,and modified gas-foaming technology.The developed orthogonally woven 3D nanofiber scaffold had a modular design and controlled fiber alignment.In vitro,the orthogonally woven 3D nanofiber scaffold exhibited adjustable mechanical properties,good cell compatibility,and easy drug loading.In vivo,for one thing,the implantation of an orthogonally woven 3D nanofiber scaffold in a full abdominal wall defect model demonstrated that extensive granulation tissue formation with enough mechanical strength could promote recovery of abdominal wall defects while reducing intestinal adhesion.Another result of diabetic wound repair experiments suggested that orthogonally woven 3D nanofiber scaffolds had a higher wound healing ratio,granulation tissue formation,collagen deposition,and re-epithelialization.Taken together,this novel orthogonally woven 3D nanofiber scaffold may provide a promising and effective approach for optimal soft tissue regeneration.展开更多
Oxygen evolution reactions(OER)are critical to electrochemical syn-thesis reactions,including hydrogen production and organic hydroge-nation.However,the high cost of existing OER catalysts(primarily Ir/Ru and its deri...Oxygen evolution reactions(OER)are critical to electrochemical syn-thesis reactions,including hydrogen production and organic hydroge-nation.However,the high cost of existing OER catalysts(primarily Ir/Ru and its derived oxides)limits their practical application for electro-chemical synthesis.To develop a low‐cost,high‐efficiency alternative,we need a deeper understanding of both the mechanisms that drive OER and the relationship between the catalyst's electronic structure and active sites.Here,we summarized recent developments of catalysts,especially focusing on the electronic structure modulation strategies and their subsequent activity enhancement.Most importantly,we pointed out the study directions for further work.展开更多
Rice has a preference for uptake of ammonium over nitrate and can use ammonium-N efficiently. Consequently, transporters mediating ammonium uptake have been extensively studied, but nitrate transporters have been larg...Rice has a preference for uptake of ammonium over nitrate and can use ammonium-N efficiently. Consequently, transporters mediating ammonium uptake have been extensively studied, but nitrate transporters have been largely ignored. Recently, some reports have shown that rice also has high capacity to acquire nitrate from growth medium, so understanding the nitrate transport system in rice roots is very important for improving N use efficiency in rice. The present study Identified four putative NRT2 and two putative NAR2 genes that encode components of the high-affinity nitrate transport system （HATS） in the rice （Oryza sativa L. subsp, japonica cv. Nipponbare） genome. OsNRT2.1 and OsNRT2.2 share an Identical coding region sequence, and their deduced proteins are closely related to those from mono-cotyledonous plants. The two NAR2 proteins are closely related to those from mono-cotyledonous plants as well. However, OsNRT2.3 and OsNRT2.4 are more closely related to Arabidopsis NRT2 proteins. Relative quantitative reverse trsnscription-polymerase chain reaction analysis showed that all of the six genes were rapidly upregulated and then downrsgulated in the roots of N-starved rice plants after they were re-supplied with 0.2 mM nitrate, but the response to nitrate differed among gene members. The results from phylogenetic tree, gene structure and expression analysis implied the divergent roles for the Individual members of the rice NRT2 and NAR2 families. High-affinity nitrate influx rates associated with nitrate induction in rice roots were investigated and were found to be regulated by external pH. Compared with the nitrate influx rates at pH 6.5, alkaline pH （pH 8.0） inhibited nitrate influx, and acidic pH （pH 5.0） enhanced the nitrate influx in 1 h nitrate induced roots, but did not significantly affect that in 4 to 8 h nitrate induced roots.展开更多
Nitrate is a major nitrogen （N） source for most crops. Nitrate uptake by root cells is a key step of nitrogen metabolism and has been widely studied at the physiological and molecular levels. Understanding how nitra...Nitrate is a major nitrogen （N） source for most crops. Nitrate uptake by root cells is a key step of nitrogen metabolism and has been widely studied at the physiological and molecular levels. Understanding how nitrate uptake is regulated will help us engineer crops with improved nitrate uptake efficiency. The present study investigated the regulation of the high-affinity nitrate transport system （HATS） by exogenous abscisic acid （ABA） and glutamine （Gin） in wheat （Triticum aestivum L.） roots. Wheat seedlings grown in nutrient solution containing 2 mmol/L nitrate as the only nitrogen source for 2weeks were deprived of N for 4d and were then transferred to nutrient solution containing 50 μmol/L ABA, and 1 mmol/L Gin in the presence or absence of 2 mmol/L nitrate for 0, 0.5, 1, 2, 4, and 8 h. Treated wheat plants were then divided into two groups. One group of plants was used to investigate the mRNA levels of the HATS components NRT2 and NAR2 genes in roots through semi-quantitative RT-PCR approach, and the other set of plants were used to measure high-affinity nitrate influx rates in a nutrient solution containing 0.2 mmol/L ^15N-labeled nitrate. The results showed that exogenous ABA induced the expression of the TaNRT2.1, TaNRT2.2, TaNRT2.3, TaNAR2.1, and TaNAR2.2 genes in roots when nitrate was not present in the nutrient solution, but did not further enhance the induction of these genes by nitrate. Glutamine, which has been shown to inhibit the expression of NRT2 genes when nitrate is present in the growth media, did not inhibit this induction. When Gin was supplied to a nitrate-free nutrient solution, the expression of these five genes in roots was induced. These results imply that the inhibition by Gin of NRT2 expression occurs only when nitrate is present in the growth media. Although exogenous ABA and Gin induced HATS genes in the roots of wheat, they did not induce nitrate influx.展开更多
基金supported by National Natural Science Foundation of China(Grant No.52275333)the Key Research&Development Program of China Hubei Province(Grant No.2023BAB089).
文摘Interlayer heat accumulation(IHA)is major challenge in the laser powder bed fusion(LPBF)process,as it exacerbates the instability of melt pools,and compromises the quality of the as-built samples.Infrared radiation monitoring is an effective method for exploring IHA.Based on the defined sequence features of interlayer infrared radiation intensity(IIRI),this study established a gated recurrent unit(GRU)neural network model for predicting IIRI in formed samples using machine learning to mitigate the IHA.The model trained on 316 L alloys achieved precise prediction results when transferred to the DZ125 superalloy,effectively managing various emergencies in the LPBF process.The truncated pyramid components were fabricated through parameter optimization based on IIRI prediction results.Compared with the non-optimized components,the CT results demonstrated a significant reduction in internal voids,with the relative density increasing from 91.6% to 98.5%.Additionally,surface roughness(Ra)decreased from 32.58μm to 19.91μm,while residual stress on the top surface was reduced from 169.21 MPa to 102.37 MPa.
基金Supported by National Natural Science Foundation of China(Grant Nos.52275333,52375335,and U22A202494)the Stabilization Support Project of AVIC Manufacturing Technology Institute(Grant No.KZ571801)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2020kfyXJJS088)the Young Elite Scientists Sponsorship Program by CAST(Grant No.YESS20200381).
文摘Triply periodic minimal surfaces(TPMS)are structures with smooth surfaces and excellent energy absorption properties.Combining new functional materials,such as shape memory alloys,with TPMS structures provides a novel and promising research field.In this study,three TPMS structures(Gyroid,Diamond,and Primitive)of Cu-11.85Al-3.2Mn-0.1Ti alloy were printed by laser powder bed fusion,which is favorable for the fabrication of complex structures.The manufacturing fidelity,mechanical response,and superelastic properties of the three structures were investigated.Stress distributions in the three structures during compression were analyzed by finite element(FE)simulation.The three structures were equipped with high-quality,glossy surfaces and uniform pores.However,due to powder adhesion and forming steps,there were volumetric errors and dimensional deviations between the samples and the CAD models.The errors were within 1.6%for the Gyroid and Diamond structures.The dimensional deviations at the nodes in the three structures were less than 0.09 mm.The microstructures of all structures wereβ1´martensite,consistent with the cubic sample.Experimental results of compression showed that the structures underwent a layer-by-layer compression failure mode,and the Primitive structures exhibited a more pronounced oscillatory process.The Diamond structures showed the highest first fracture stress and strain of 164.67 MPa and 13.89%,respectively.It also possessed the lowest yield strength(61.97 MPa)and the best energy absorption properties(7.6 MJ/m3).Through the deformation analysis,the Gyroid and Diamond structures were found to fracture at a 45°direction,while the Primitive structures fractured horizontally.These findings were consistent with the results obtained from the FE simulation,which showed equivalent stress distributions.After applying various pre-strains,the Diamond structures displayed the highest superelastic strain of up to 3.53%.The superelastic recovery of all samples ranged from 63.5%to 71.5%.
基金supported by the National Natural Science Foundation of China(Nos.52275333,52375335 and U22A202494)the Stabilization Support Project of AVIC Manufacturing Technology Institute(No.KZ571801)+1 种基金the Knowledge Innovation Special Project of Wuhan(No.2022010801010302)the Fundamental Research Funds for the Central Universities(No.YCJJ20230359).
文摘WE43 is a high-strength magnesium alloy containing rare-earth elements such as Y,Gd and Nd.Nevertheless,how to further obtain the balance of strength and ductility,as well as the manufacture of complex structures is still a dilemma for its engineering application.In this study,WE43 alloy samples withfine microstructures,high densification and excellent mechanical properties were successfully prepared by laser powder bed fusion(LPBF)additive manufacturing.The optimal process window was established,and the formation mechanisms of three types of porosity defects were revealed,namely lack-of-fusion pores,meltfluctuation-induced pores,and keyhole-induced pores.With the combined process of laser power of 200 W and scanning speed of 600 mm/s,samples with a high density of 99.89%were obtained.Furthermore,periodic heterogeneous microstructure was prepared along the build direction,i.e.,fine grains(∼4.1μm)at melt pool boundaries and coarse grain(∼23.6μm)inside melt pool.This was mainly due to the preferential precipitation of Zr and Mg_(3)(Gd,Nd)nano-precipitates at the melt pool boundaries providing nucleation sites for the grains.This special feature could provide an extra hetero-deformation induced(HDI)strengthening and retard fracture.The optimal tensile yield strength,ultimate tensile strength and elongation at break were 276±1 MPa,292±1 MPa and 6.1±0.2%,respectively.The obtained tensile properties were superior to those of other magnesium alloys and those fabricated by other processes.The solid solution strengthening(∼24.5%),grain boundary strengthening(∼14.4%)and HDI strengthening(∼32.2%)were the main sources of high yield strength.This work provides a guidance on studying the pore defect suppression and strengthening mechanisms of WE43 alloy and other magnesium alloys produced by LPBF.
基金The Zhejiang Medical and Health Science and Technology Program,China,No.2021KY205 and No.2024KY139The Wenzhou Science and Technology Plan Project,China,No.Y2023111.
文摘In this editorial,we examined a recent article in the World Journal of Gastroenterology that focused on sepsis-associated liver injury(SLI)and its treatment.SLI is a serious complication of sepsis,primarily caused by microcirculatory disturbances,the gut-liver axis,and inflammatory responses.Specific treatment recommendations for SLI are lacking.The gut-liver axis represents a potential therapeutic target,with metformin showing promise in modulating the gut microbiome and enhancing intestinal barrier function.Although immunomodulatory therapies are being explored,anti-tumor necrosis factor agents and interleukin-1 receptor antagonists have not demonstrated significant clinical benefits.Statins may reduce liver inflammation and prevent injury in sepsis,but their clinical application is limited.Reduced D-related human leucocyte antigen expression on monocytes and lymphocytes suggests immune suppression in patients,indicating that corticosteroids could reverse clinical deterioration in severe infections and address adrenal cortical insufficiency.Current large-scale studies on glucocorticoid therapy for sepsis have yielded mixed results,likely due to inadequate assessment of the immune status of the host.Future research should prioritize the development of personalized immunotherapy tailored to patients’immune profiles,focusing on identifying novel indicators of immune status and advancing immunomodulatory targets and therapeutics for septic patients.
基金supported by National Natural Science Foundation of China(Grant Nos.52235008,U2037203,and U2341270)Key Research and Development Plan of Hubei Province(2022BAA030).
文摘Additive manufacturing(AM)technology enables the creation of a wide variety of assemblies and complex shapes from three-dimensional model data in a bottom-up,layer-by-layer manner.Therefore,AM has revolutionized the modern manufacturing industry,attracting increasing interest from both academic and industrial fields.The Rapid Manufacturing Center(RMC)of the School of Materials Science and Engineering at the Huazhong Univer-sity of Science and Technology(HUST),one of the earliest and most powerful AM research teams in China,has been engaged in AM research since 1991.Aiming to address the“stuck neck”problems of specific high-strength products for AM,the RMC has conducted full-chain research in the aspects of special materials,processes,equip-ment,and applications for AM.Moreover,it has formed a multi-disciplinary research team over the past three decades.Relevant research achievements in the AM field include winning five national awards,more than ten first prizes,and more than ten second prizes at the provincial and ministerial levels.The RMC was complimented as“the world’s most influential organization in the laser AM field in 2018”by Virtual and Physical Prototyping(an international authoritative magazine of AM).Moreover,their industrialization achievements were evaluated as“having affected countries such as Singapore,South Korea,and the United States”by an international author-itative Wohlers Report on AM.In this study,we first summarize the representative research achievements of the RMC in the AM field.These include the preparation and processing technology of high-performance polymeric,metallic,and ceramic materials for AM;advanced processing technology and software/equipment for AM;and typical AM-fabricated products and their applications.Further,we discuss the latest research achievements in cutting-edge 4D printing in terms of feedstock selection,printing processes,induction strategies,and potential ap-plications.Finally,we provide insights into the future directions of AM technology development:(ⅰ)Evolving from three-dimensional printing to multi-dimensional printing,(ⅱ)transitioning from plane slicing to curved surface slicing to woven slicing,(ⅲ)enhancing efficient formation from dot-line-sheet-volume printing,(ⅳ)shifting from single material to multi-materials AM,(ⅴ)advancing from the multiscale direction of macroscopic-mesoscopic-microscopic structures,(ⅵ)integrating material preparation with forming integration,(ⅶ)expanding from small batch to large batch.
文摘Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)holds significant promise for sustainable energy conversion,with cobalt phthalocyanine(CoPc)emerging as a notable catalyst due to its high CO selectivity.However,CoPc's efficacy is hindered by its limited ability to provide sufficient proton for the protonation process,particularly at industrial current densities.Herein,we introduce defect-engineered carbon nanotubes(d-CNT)to augment proton feeding for CO_(2)RR over CoPc,achieved by expediting water dissociation.Our kinetic measurements and in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy reveal d-CNT significantly enhances proton feeding,thereby facilitating CO_(2)activation to*COOH in CoPc.Density functional theory calculations corroborate these findings,illustrating that d-CNT decreases the barrier to water dissociation.Consequently,the CoPc/d-CNT mixture demonstrates robust performance,achieving 500 mA cm^(-2)for CO_(2)RR with CO selectivity exceeding 96%.Notably,CoPc/d-CNT remains stability for a duration of 20 h under a substantial current density of 150 mA cm^(-2).The study broadens the scope of practical applications for molecular catalysts in CO_(2)RR,marking a significant step towards sustainable energy conversion.
文摘碱性析氢反应(HER)可将间歇性可再生能源转化为可存储的清洁能源,因而备受关注.然而,水解离速度缓慢以及H中间体(*H)吸附和解吸困难限制了碱性HER的进一步发展.目前,针对碱性电解水解离缓慢问题,通常采用调整电催化剂结构降低水分解热动力学能垒,以及改变三相界面微环境加速中间产物的扩散等方法来促进水分解进行.此外,可以通过调控活性位点电子结构来优化*H的吸脱附.但是采用单一的策略很难同时促进H_(2)O的解离和*H的吸脱附,难以获得令人满意的碱性HER性能.因此,探索一种能同时促进H_(2)O的解离和*H的吸脱附协同策略对提升碱性HER的性能至关重要.本文提出了一种协同策略,通过构建高曲率二硫化钴纳米针(CoS_(2)NNs)和原子级铜(Cu)的掺杂分别实现诱导纳米尺度的局域电场和原子尺度的电子局域化,从而促进碱性HER的H_(2)O解离和*H吸脱附.首先,采用有限元法模拟和密度泛函理论计算,从理论上分别证实了纳米尺度局域电场可以加速H_(2)O解离以及原子尺度电子局域化可以促进*H吸附.受理论计算结果启发,通过一步水热法和原位硫化相结合的方法制备了高曲率的Cu掺杂CoS_(2)纳米针(Cu-CoS_(2)NNs).采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)和四探针测试等技术进行表征,研究了Cu-CoS_(2)NNs的形貌、物相结构、化学组成和导电性.结果表明,在Cu原子引入后,Cu-CoS_(2)NNs依然保持着高曲率的纳米针结构,证明了Cu在CoS_(2)NNs中的原子分散状态.相较于低曲率的Cu掺杂CoS_(2)纳米线(Cu-CoS_(2)NWs),Cu-CoS_(2)NNs只存在形貌上的区别,二者的化学组成和比例均非常接近.同时,上述材料都具有很强的导电性,且电导率基本相同,这与有限元模拟结果一致.原位衰减全反射红外光谱和电响应测试结果表明,Cu-CoS_(2)NNs具有较好的解离H_(2)O和吸附*H的能力.在1 mol L^(-1)KOH溶液和10 mA cm^(-2)电流密度下,该催化剂的析氢过电位仅为64 mV,展现出较好的电化学析氢性能.催化剂还表现出非常好的碱性析氢稳定性,在标准氢电势(RHE)-0.18 V下,可在100 mA cm^(-2)电流密度下稳定工作达100 h.综上所述,本文通过诱导局域电场和电子局域化构建了一种协同策略,所制备的Cu-CoS_(2)NNs表现出很好的催化碱性HER性能和应用前景,为碱性HER电催化剂的理性设计提供了一定的参考.
基金financially supported by the National Key Research and Development Program of China “the Clinical Application of Personalized Implant Prosthesis Additive Manufacturing Process Research” (No. 2016YFB1101303)the National Natural Science Foundation of China (Nos. 51705170 and 51905192)the China Postdoctoral Science Foundation (Nos. 2017M620312 and 2018T110756)。
文摘This paper presents a comprehensive study conducted to optimize the selective laser melting(SLM)parameters and subsequent heat-treatment temperatures for near-α high-temperature titanium alloy Ti-6 Al-2 Zr-1 Mo-1 V(TA15),which is widely used in the aerospace industry.Based on the surface morphology and relative density analysis,the optimized process parameters were:laser power from 230 W to 380 W,scan speed from 675 mm/s to 800 mm/s,scan spacing of 0.12 mm,and layer thickness of0.03 mm.The effects of the laser power and the layer thickness on the phase constitutions,microstructure features,as well as room-temperature and high-temperature(500℃) tensile properties,were then studied to obtain an in-depth understanding of SLM-built TA15.Six typical temperatures(650,750,850,950,1000 and 1100℃) covering three representative temperature ranges,i.e.,martensite partial decomposition temperature range,martensite complete decomposition temperature range and above βtransus temperature,were subsequently selected as heat-treatment temperatures.The heat treatmentmicrostructure-mechanical property relationships of SLM-built TA15 were elucidated in detail.These results provide valuable information on the development of SLM-built TA15 alloy for industrial applications,and these findings are also beneficial to additive manufacturing of other near-α Ti alloys with desirable high-temperature properties.
基金financially supported by Guangdong Province Key Field R&D Program, China (No. 2019B01 0935001)the National Nature Science Foundation of China (No. 51905192)the Fundamental Research Funds for the Central Universities (No. FRT-TP-20-006A2)
文摘The Shima yield criterion used in finite element analysis for nickel-based superalloy powder compact during hot isostatic pressing(HIP) was modified through uniaxial compression experiments. The influence of cylindrical capsule characteristics on FGH4096M superalloy powder compact deformation and densification behavior during HIP was investigated through simulations and experiments. Results revealed the simulation shrinkage prediction fitted well with the experimental shrinkage including a maximum shrinkage error of 1.5%. It was shown that the axial shrinkage was 1.7% higher than radial shrinkage for a cylindrical capsule with the size of ∮50 mm × 100 mm due to the force arm difference along the axial and radial direction of the capsule. The stress deviated from the isostatic state in the capsule led to the uneven shrinkage and non-uniform densification of the powder compact. The ratio of the maximum radial displacement to axial displacement increased from0.47 to 0.75 with the capsule thickness increasing from 2 to 4 mm. The pressure transmission is related to the capsule thickness, the capsule material performance, and physical parameters in the HIP process.
基金The financial support from Shenzhen Basic Research Program(No.JCYJ20170307140752183)Guangdong Natural Science Foundation(Nos.S2017A030313076,2020A1515010661)is gratefully acknowledged。
文摘Rheumatoid arthritis(RA),as a chronic autoimmune disease,damages the bone and cartilage of patients,and even leads to disability.Therefore,the diagnosis and treatment of RA is particularly important.However,due to the complexity of RA,it is difficult to make effective early diagnosis of RA,which is detrimental to RA treatment.Besides,long-term intake of anti-RA drugs can also cause damage to patients' organs.The emergence of nanotechnology provides the new train of thoughts for the diagnosis and treatment of RA.And the combination of diagnosis and therapy is an ideal method to solve the problem of disease management of RA patients.In this review,we summarize the mechanism and microenvironment of RA,discuss the commonly used diagnostic techniques and therapeutic drugs for RA,and review their advantages and disadvantages.New nanotherapy strategies such as drug-carrying nanoparticles,PTT,PDT are listed,and their applications in RA treatment are also summarized.In addition,multimodal imaging,combined therapy and responsive diagnosis and treatment are also summarized as important contents.At last,we also review typical nanocarriers that can be used in the integration of diagnosis and therapy,and discussed their potential applications in RA theranostics.
基金supported in partial by the National Natural Science Foundation of China(Nos.21232002,21372254,21621064 and 21672255)
文摘A dermatan sulfate （DS） repeating disaccharide analog, β-L-idopyranosiduronate-（1→3）-2-amino-2- deoxy-4,6-di-O-sulfo-β-D-galactopyranoside, has been convergently synthesized and successfully applied to prepare the GAG-functionalized gold glyconanoparticle. This new material exhibited good anti-inflammatory activity which was comparable to that of the drug ibuprofen incarrageenan-induced paw edema in a rat model.
基金sponsored by the National Natural Science Foundation of China(Grant No.51775208,51922044)the Hubei Science Fund for Distinguished Young Scholars(No.0216110085)+1 种基金Wuhan Plan of Science and Technology(No.2018010401011281)the Academic Frontier Youth Team(2018QYTD04)at Huazhong University of Science and Technology(HUST).
文摘This paper systematically investigated the effect of solution and artificial aging heat treatments on the microstructural evolution and mechanical properties of TiB/Ti-6Al-4V composites in situ fabricated by selective laser melting.The results showed that the fully martensite microstructure with TiB clusters of the as-built samples was transformed into lamellarα+βmicrostructure with TiB strips after solution heat treatment.With increasing the temperature,theαlaths and TiB particles coarsened and theβvolume fraction increased.After aging heat treatment,βvolume fraction decreased and TiB had no obvious changes.A superior combination of the yield strength of(1146.8±28.2)MPa and even higher plasticity and ultimate compressive strength((1680.1±18.3)MPa)than the as-built ones was obtained by solution heat treatment at 1000℃+water quenching and aging at 600℃for 6 hþair cooling.
文摘Radical prostatectomy （RP） has been a widely accepted and standard treat-ment for clinically localized and locally advanced prostate cancer. However, effective clinical management of RP patient remains being challenged, given that conventional prognostic factors, including Gleason score, pT stage, surgical margin status and presurgery serum prostatespecific antigen （PSA）,
基金the Ministry of Education(grant nos.MOE-T2EP30120-0007 and Tier-1 RG107/23)the National Research Foundation(grant no.NRF-CRP22-2019-0002)of Singapore for their generous financial support.
文摘C-3-Functionalized steroids represent a pivotal class of molecules with diverse and significant biological functions.However,the reliable chemical synthesis of these compounds is frequently impeded by sub-strate sensitivity and the propensity for i-steroid rearrangement of steroidal cations.Herein,we dis-close an efficient Sc(OTf)(_3)-catalyzed steroidation reaction that utilizes readily available steroidal tri-chloroacetimidates as donors.We have explored a broad spectrum of steroidal donors and acceptor substrates,including biomolecules such as sugars,steroids,amino acids,terpenoids,dye molecules,and small-molecule drugs,all of which possess multiple intricate functionalities.This reaction has been dem-onstrated to generate novel steroid chimeras with excellent regio-and diastereocontrol within 1 h under mild conditions.We have integrated a series of experimental investigations with density functional theory calculations to elucidate the reaction mechanism.Our findings reveal a controlled retro-i-steroid rearrangement of the kinetically favored and acid-activable C-6 i-steroid intermediates cata-lyzed by an in-situ generated protonic acid catalyst.
基金provided by the Guangdong Basic and Applied Basic Research Foundation(2022B1515020017,2021A1515110426)the National Natural Science Foundation of China(32070113).
文摘Zeaxanthin,an oxygenated carotenoid derivative with potent antioxidative properties,is produced by many organism taxa.Flavobacteriaceae are widely distributed in marine environments;however,the zeaxanthin biosynthesis property in this family remains incompletely explored.Here,we characterized zeaxanthin production by marine Flavobacteriaceae strains and elucidated underlying molecular mechanisms.Eight Flavobacteriaceae strains were isolated from the phycosphere of various dinoflagellates.Analyses of the zeaxanthin production in these strains revealed yields ranging from 5 to 3289μg/g of dry cell weight.Genomic and molecular biology analyses revealed the biosynthesized zeaxanthin through the mevalonate(MVA)pathway diverging from the 2-C-methyl-d-erythritol-4-phosphate(MEP)pathway commonly observed in most Gram-negative bacteria.Furthermore,comprehensive genome analyses of 322 culturable marine Flavobacteriale strains indicated that the majority of Flavobacteriaceae members possess the potential to synthesize zeaxanthin using precursors derived from the MVA pathway.These data provide insight into the zeaxanthin biosynthesis property in marine Flavobacteriaceae strains,highlighting their ecological and biotechnological relevance.
基金supported by The National Natural Science Foundation of China(61174117)the Foundation of Scientific Research Project of Jinjiang Science and Education Development Center of Fuzhou Univerdity(2019-JJFDKY-33).
文摘In order to effectively utilize the dielectric response characteristics of transformers to diagnose the insulation state,this paper proposes a two-level hybrid optimization method for analyzing time-domain dielectric response characteristics.The optimization algorithm is based on the combined statistical indicators(CSI)and random forest(RF)theory.The initial feature space set is formed with 23 time-domain characteristics.In the first-level stage,statistical indices correlation,distance,and information indicators are integrated to assess the synthesis score of the characteristics,while highly redundant and lowclass discrimination characteristics are eliminated from the initial space set.In the second-level stage,the Random Forest based outside bagging data theory is introduced to evaluate the least important characteristics,and the characteristics with low importance indices are excluded to obtain the final optimal feature space set.The proposed method is carried out on 82 sets of data from actual dielectric response tests on oil-paper insulation transformers.Finally,the final optimal feature space set,along with several other data sets,is tested via different diagnosis methods.The results show that the optimal feature space set obtained via the proposed method outperforms other feature space sets in terms of better adaptability and diagnosis accuracy.
基金supported by the National Natural Science Foundation of China(grant no.82102334 to S.Chen,grant no.82171622 to L.Liu,grant no.81971832 to L.Yi)The Key Foundation of Zhejiang Provincial Natural Science Foundation(grant no.LZ22C100001 to S.C.)+1 种基金The Wenzhou Science and Technology Major Project(grant no.ZY2022026 to S.Chen)Wenzhou Science and Technology Project(grant no.ZY2023144 to Z.Huang).
文摘Repairing large-area soft tissue defects caused by traumas is a major surgical challenge.Developing multifunctional scaffolds with suitable scalability and favorable cellular response is crucial for soft tissue regeneration.In this study,we developed an orthogonally woven three-dimensional(3D)nanofiber scaffold combining electrospinning,weaving,and modified gas-foaming technology.The developed orthogonally woven 3D nanofiber scaffold had a modular design and controlled fiber alignment.In vitro,the orthogonally woven 3D nanofiber scaffold exhibited adjustable mechanical properties,good cell compatibility,and easy drug loading.In vivo,for one thing,the implantation of an orthogonally woven 3D nanofiber scaffold in a full abdominal wall defect model demonstrated that extensive granulation tissue formation with enough mechanical strength could promote recovery of abdominal wall defects while reducing intestinal adhesion.Another result of diabetic wound repair experiments suggested that orthogonally woven 3D nanofiber scaffolds had a higher wound healing ratio,granulation tissue formation,collagen deposition,and re-epithelialization.Taken together,this novel orthogonally woven 3D nanofiber scaffold may provide a promising and effective approach for optimal soft tissue regeneration.
基金Shenzhen fundamental research funding,Grant/Award Numbers:JCYJ20200109141216566,JCYJ20210324115809026,JCYJ20220818100212027Guangdong scientific program,Grant/Award Number:2019QN01L057+2 种基金National Key Research and Development Project,Grant/Award Numbers:2022YFA1203400,2022YFA1503900Southern University of Science and TechnologyDevelopment and Reform Commission of Shenzhen Municipality。
文摘Oxygen evolution reactions(OER)are critical to electrochemical syn-thesis reactions,including hydrogen production and organic hydroge-nation.However,the high cost of existing OER catalysts(primarily Ir/Ru and its derived oxides)limits their practical application for electro-chemical synthesis.To develop a low‐cost,high‐efficiency alternative,we need a deeper understanding of both the mechanisms that drive OER and the relationship between the catalyst's electronic structure and active sites.Here,we summarized recent developments of catalysts,especially focusing on the electronic structure modulation strategies and their subsequent activity enhancement.Most importantly,we pointed out the study directions for further work.
基金the National Natural Science Foundation of China (30390080and 30521001)the Ministry of Science and Technology of China(2005CB120900 and 2004CB117200)
文摘Rice has a preference for uptake of ammonium over nitrate and can use ammonium-N efficiently. Consequently, transporters mediating ammonium uptake have been extensively studied, but nitrate transporters have been largely ignored. Recently, some reports have shown that rice also has high capacity to acquire nitrate from growth medium, so understanding the nitrate transport system in rice roots is very important for improving N use efficiency in rice. The present study Identified four putative NRT2 and two putative NAR2 genes that encode components of the high-affinity nitrate transport system （HATS） in the rice （Oryza sativa L. subsp, japonica cv. Nipponbare） genome. OsNRT2.1 and OsNRT2.2 share an Identical coding region sequence, and their deduced proteins are closely related to those from mono-cotyledonous plants. The two NAR2 proteins are closely related to those from mono-cotyledonous plants as well. However, OsNRT2.3 and OsNRT2.4 are more closely related to Arabidopsis NRT2 proteins. Relative quantitative reverse trsnscription-polymerase chain reaction analysis showed that all of the six genes were rapidly upregulated and then downrsgulated in the roots of N-starved rice plants after they were re-supplied with 0.2 mM nitrate, but the response to nitrate differed among gene members. The results from phylogenetic tree, gene structure and expression analysis implied the divergent roles for the Individual members of the rice NRT2 and NAR2 families. High-affinity nitrate influx rates associated with nitrate induction in rice roots were investigated and were found to be regulated by external pH. Compared with the nitrate influx rates at pH 6.5, alkaline pH （pH 8.0） inhibited nitrate influx, and acidic pH （pH 5.0） enhanced the nitrate influx in 1 h nitrate induced roots, but did not significantly affect that in 4 to 8 h nitrate induced roots.
基金Supported by the National Natural Science Foundation of China(30390083 and 30521001)the State Key Basic Research and Development Plan of China(2005CB120904 and 2004CB117200)
文摘Nitrate is a major nitrogen （N） source for most crops. Nitrate uptake by root cells is a key step of nitrogen metabolism and has been widely studied at the physiological and molecular levels. Understanding how nitrate uptake is regulated will help us engineer crops with improved nitrate uptake efficiency. The present study investigated the regulation of the high-affinity nitrate transport system （HATS） by exogenous abscisic acid （ABA） and glutamine （Gin） in wheat （Triticum aestivum L.） roots. Wheat seedlings grown in nutrient solution containing 2 mmol/L nitrate as the only nitrogen source for 2weeks were deprived of N for 4d and were then transferred to nutrient solution containing 50 μmol/L ABA, and 1 mmol/L Gin in the presence or absence of 2 mmol/L nitrate for 0, 0.5, 1, 2, 4, and 8 h. Treated wheat plants were then divided into two groups. One group of plants was used to investigate the mRNA levels of the HATS components NRT2 and NAR2 genes in roots through semi-quantitative RT-PCR approach, and the other set of plants were used to measure high-affinity nitrate influx rates in a nutrient solution containing 0.2 mmol/L ^15N-labeled nitrate. The results showed that exogenous ABA induced the expression of the TaNRT2.1, TaNRT2.2, TaNRT2.3, TaNAR2.1, and TaNAR2.2 genes in roots when nitrate was not present in the nutrient solution, but did not further enhance the induction of these genes by nitrate. Glutamine, which has been shown to inhibit the expression of NRT2 genes when nitrate is present in the growth media, did not inhibit this induction. When Gin was supplied to a nitrate-free nutrient solution, the expression of these five genes in roots was induced. These results imply that the inhibition by Gin of NRT2 expression occurs only when nitrate is present in the growth media. Although exogenous ABA and Gin induced HATS genes in the roots of wheat, they did not induce nitrate influx.
