OsNPF3.1,a member of the NRT1/PTR family,increases nitrogen use efficiency and biomass production in rice

The overuse of nitrogen(N)fertilizer in fields has increased production costs and raised environmental concerns.Increasing the N use efficiency(NUE)of rice varieties is crucial for sustainable agriculture.Here we report the cloning and characterization of OsNPF3.1,a gene that controls rice NUE.An amino acid mutation in the OsNPF3.1 coding region caused different NUEs in wild and cultivated rice.OsNPF3.1,which is expressed mainly in the aerial parts of rice,also affects rice plant height,heading date,and thousand-grain weight.The OsNPF3.1 protein is located in the plasma membrane.When OsNPF3.1 was subjected to artificial selection,two naturally varying loci were associated with NUE,of which OsNPF3.1Chr6_8741040differed between indica and japonica rice.OsNPF3.1 can be used as a new target gene for breeding rice varieties with high NUE.

Transcriptome analysis reveals potential genes associated with plant height in rice

Plant height(PH)is a complex trait regulated by the environment and multiple genes.PH directly affects crop yield,harvest index,and lodging resistance.From plant dwarf mutants,many genes related to PH have been identified and described.Nonetheless,the molecular mechanism of height regulation in high-culm rice mutants has not been well studied.By using transcriptome and weighted gene co-expression network analysis(WGCNA),we identified the differentially expressed genes(DEGs)between high-culm rice mutants(MUT)and wild-type(WT)and explored the key pathways and potential candidate genes involved in PH regulation.Transcriptome analysis identified a total of 2,184 DEGs,of which 1,317 were identified at the jointing stage and 1,512 were identified at the heading stage.Kyoto Encyclopedia of Genes and Genomes enrichment showed that the enrichment pathways were mainly involved in plant hormone signal transduction,ABC transportation,and steroid hormone biosynthesis.Among these metabolic pathways,LOC_Os05g43910 and LOC_Os01g35030 were auxin(IAA)-related genes,up-regulated in MUT and LOC_Os02g08500(LEPTO1),LOC_Os11g04720,and LOC_Os12g04500 were cytokinin(CK)-related genes,downregulated in MUT.The WGCNA identified four modules(light cyan,dark grey,grey,and pale turquoise)closely related to PH,and seven key genes were screened from these modules,of which two were up-regulated cell wallrelated genes(LOC_Os01g26174(OsWAK5),LOC_Os06g05050)in MUT,and one gibberellic acid(GA)gene(LOC_Os06g37364,OsKO2)was also up-regulated.These genes might be closely related to PH regulation.These findings help us better understand the transcriptional regulation of rice plant growth and development and provide a theoretical basis for mapping and cloning the PH regulatory genes.

Development of Integrated Computational Materials Engineering(ICME)Model for Mg Alloy Design and Process Optimization

Integrated computational materials engineering(ICME)has emerged to be one of the most powerful materials genome engineering(MGE)approaches in designing new materials and manufacturing processes in recent years.It has successfully deployed many new products for the electronic,automotive,and aerospace industries.This paper reviews the current status of research on first principles in the design of high-strength Mg alloys,discusses the application of crystal plasticity finite element models to the microscale slip,twinning,microstructure morphology,texture evolution,and macroscopic forming of Mg alloys,and introduces the research progress of crystal plasticity finite element models and phase field models,meta cellular automata models and first principles coupled models respectively,around the need for multi-scale coupled simulations of Mg alloys.The key technology obstacles of integrating the first principles,crystal plasticity finite element,and microstructure models for Mg alloys have been solved.This paper can provide a reference for the design of new Mg alloy compositions and the development of high-performance Mg alloys.

Integrated Computational Materials Engineering for the Development and Design of High Modulus Al Alloys

Integrated computational materials engineering(ICME)is to integrate multi-scale computational simulations and key experimental methods such as macroscopic,mesoscopic,and microscopic into the whole process of Al alloys design and development,which enables the design and development of Al alloys to upgrade from traditional empirical to the integration of compositionprocess-structure-mechanical property,thus greatly accelerating its development speed and reducing its development cost.This study combines calculation of phase diagram(CALPHAD),Finite element calculations,first principle calculations,and microstructure characterization methods to predict and regulate the formation and structure of composite precipitates from the design of highmodulus Al alloy compositions and optimize the casting process parameters to inhibit the formation of micropore defects in the casting process,and the final tensile strength of Al alloys reaches420 MPa and Young's modulus reaches more than 88 GPa,which achieves the design goal of the high strength and modulus Al alloys,and establishes a new mode of the design and development of the strength/modulus Al alloys.

Design and Analysis of Spatial Modulation Based Orthogonal Time Frequency Space System

In this paper,we design a spatial modulation based orthogonal time frequency space(SMOTFS)system to achieve improved transmission reliability and meet the high transmission rate and highspeed demands of future mobile communications,which fully utilizes the characteristics of spatial modulation(SM)and orthogonal time frequency space(OTFS)transmission.The detailed system design and signal processing of the SM-OTFS system have been presented.The closed-form expressions of the average symbol error rate(ASER)and average bit error rate(ABER)of the SM-OTFS system have been derived over the delay-Doppler channel with the help of the union bounding technique and moment-generating function(MGF).Meanwhile,the system complexity has been evaluated.Numerical results verify the correctness of the theoretical ASER and ABER analysis of the SM-OTFS system in the high signal-to-noise ratio(SNR)regions and also show that the SM-OTFS system outperforms the traditional SM based orthogonal frequency division multiplexing(SM-OFDM)system with limited complexity increase under mobile conditions,especially in high mobility scenarios.

Inter-Carrier Interference-Aware Sparse Time-Varying Underwater Acoustic Channel Estimation Based on Fast Reconstruction Algorithm

In this paper,a fast orthogonal matching pursuit(OMP)algorithm based on optimized iterative process is proposed for sparse time-varying underwater acoustic(UWA)channel estimation.The channel estimation consists of calculating amplitude,delay and Doppler scaling factor of each path using the received multi-path signal.This algorithm,called as OIP-FOMP,can reduce the computationally complexity of the traditional OMP algorithm and maintain accuracy in the presence of severe inter-carrier interference that exists in the time-varying UWA channels.In this algorithm,repeated inner product operations used in the OMP algorithm are removed by calculating the candidate path signature Hermitian inner product matrix in advance.Efficient QR decomposition is used to estimate the path amplitude,and the problem of reconstruction failure caused by inaccurate delay selection is avoided by optimizing the Hermitian inner product matrix.Theoretical analysis and simulation results show that the computational complexity of the OIP-FOMP algorithm is reduced by about 1/4 compared with the OMP algorithm,without any loss of accuracy.

Validation of the Red Pericarp Gene from 419 Rice Landraces in Guangxi via Genome-wide Association Studies

Rice has different colors of pericarp, such as red, white and black. Red rice pericarp is rich in proanthocyanins, which have antioxidant properties and are beneficial to human health. In the present study, we analyzed the red-pericarp gene Rc of 419 rice landraces in Guangxi by genome-wide association study （GWAS）, and validated that the Rc gene regulated the red periearp trait in flee. By analyzing the genomie DNA of 97 red-pericarp flee eultivars, we identified two new alleles in C139 and C323. Then, the exons of Rcc＇9 and Rcc were sequenced with Sanger method, and the results demonstrated that the natural mutations within Re ene resulted in the two alleles Rcc and Rcc.

Effect of Carbides and γ/γ' Eutectic on Crack Initiation and Propagation in Ni-based Superalloy

The Ni-based Udemit720Li superalloy tends to form largeγ/γ'eutectic on grain boundaries(GBs)during solidification due to the addition of excessive Al and Ti elements,which provides convenience to study the effect of carbide andγ/γ'eutectic on crack initiation and propagation during tensile process.In this paper,Udemit720Li superalloy samples were prepared by induction melting casting method,arc melting and suction casting method.The microstructure,tensile properties and mechanism of crack initiation and propagation in Ni-based superalloy fabricated by two methods are investigated.The results exhibitγ/γ'eutectic accelerates the stress concentration at GB and thus leads to premature fracture failure.The samples with grain-boundary eutectic have higher strain hardening rate,but their cumulative and local misorientations are lower.For samples without eutectic at GB,the primary crack initiates at grain-boundary carbide along GB and extends along GB or into grain matrix,and exhibits better deformation performance and dislocation storage capacity within grains.

Unexpected nucleation mechanism of T1 precipitates by Eshelby inclusion with unstable stacking faults

Aluminum-lithium(Al-Li)alloy is one of the most promising lightweight structural materials in the aeronautic and aerospace industries.The key to achieving their excellent mechanical properties lies in tailoring T1 strengthening precipitates;however,the nucleation of such nanoparticles remains unknown.Combining atomic resolution HAADF-STEM with first-principles calculations based on the density functional theory(DFT),here,we report a counterintuitive nucleation mechanism of the T1 that evolves from an Eshelby inclusion with unstable stacking faults.This precursor is accelerated by Ag-Mg clusters to reduce the barrier,forming the structural framework.In addition,these Ag-Mg clusters trap the free Cu and Li to prepare the chemical compositions for T1.Our findings provide a new perspective on the phase transformations of complex precipitates through solute clusters in terms of geometric structure and chemical bonding functions.

Achieving highest Young’s modulus in Al-Li by tracing the size and bonding evolution of Li-rich precipitates

For decades,it has been well accepted that every 1 wt.%Li addition to Al will reduce Al alloy’s density by 3%and increase its Young’s modulus by 6%.However,the fundamental mechanism of modulus improve-ments stays controversial though all studies agreed that the contribution of such a substantial boosting comes from Li-rich clusters either in solid solution or precipitations.In this study,we experimentally produce nano-sized Li-rich clusters by non-equilibrium solidification using centrifugal casting and trace their evolutions as a function of subsequent heat treatments.High-resolution transmission electron mi-croscopy(HRTEM)reveals a further decrease in the lattice constants of Li-rich regions from the as-cast(0.406 nm),solid solution(0.405 nm)to the aged state(0.401 nm),while Young’s modulus of the Al-Li al-loy reaches 89.16 GPa.Small-angle neutron scattering(SANS)experiments and first-principle calculations based on density functional theory have shown both the bond strength around precipitates and the size of those Li-rich region dominate Young’s modulus.At the beginning,it is volumetric compression due to Li addition that increases modulus,tightening the Al-Al potential curves.In the end,it is the Al-Al and Al-Li valence bonds in Al 3 Li at large size and high-volume fraction which increase its second derivative of internal energy and thus Young’s modulus.

腹膜后内寄生胎产前和新生儿期的临床与超声影像学特征

目的探讨腹膜后内寄生胎产前和新生儿期的临床及超声影像特征。方法收集湖北省妇幼保健院2016年1月至2020年1月产前超声检查发现宿主胎儿腹腔内肿块、于新生儿期手术并经病理证实为腹膜后内寄生胎8例。总结产前和新生儿期的临床资料及超声影像资料,并将超声特征与手术、病理结果进行对照分析。结果8例腹膜后内寄生胎的超声影像特征为:囊实性肿块;肿块边界清楚,囊壁薄;实质性成分(寄生胎)随孕龄增长而增大,并渐具胎儿雏形,超声易识别发育不良的脊柱轴、颅骨环、长骨、肢芽、增厚的皮肤等结构,实质性成分周围包绕囊液;寄生胎有血管蒂与宿主血管分支相连;肿块多数位于腹腔中轴线稍偏左或偏右、脊柱和腹主动脉前方、双肾之间。临床结局为:8例均于出生后5~27 d手术,其中1例合并回肠美克尔憩室,1例合并成熟囊性畸胎瘤;其中4例行开腹手术,1例腹腔镜转开腹手术,3例行腹腔镜手术。8例术后均恢复良好,随访至今均未复发。病理结果为:8例腹膜后内寄生胎中单寄生胎6例,双寄生胎2例,共10个寄生胎。与病理结果对照,超声检出率最高的是骨性组织(9/9)、颅骨环(2/2);其次是长骨(6/7)、脊柱轴(6/8)、肢芽(6/9)、血管蒂(6/10)和皮肤(4/10)。结论腹膜后内寄生胎超声影像有特征性表现,并与临床手术及病理表现相对应。系统规范的超声检查可尽早正确诊断内寄生胎,对于宿主胎儿出生后选择合适的诊疗方法和治疗时机具有十分重要的意义。

Comparative Study on Wire-Arc Additive Manufacturing and Conventional Casting of Al–Si Alloys:Porosity,Microstructure and Mechanical Property

Here,we compare the porosity,microstructure and mechanical property of 4047 Al–Si alloys prepared by wire-arc additive manufacturing(WAAM)and conventional casting.X-ray microscopy reveals that WAAM causes a higher volume fraction of gas pores in comparison with conventional casting.Effective refi nements ofα-Al dendrites,eutectic Si particles and Ferich intermetallic compounds are achieved by WAAM,resulting from its rapid solidifi cation process.Both ultimate tensile strength(UTS,up to 205.6 MPa)and yield stress(YS,up to 98.0 MPa)are improved by WAAM at the expense of elongation after fracture.The mechanical property anisotropy between scanning direction and build direction is minimal for alloys via WAAM.Additional microstructure refi nement and strength enhancement are enabled by increasing the travel speed of welding torch from 300 to 420 mm/min.