Ultrafine ordered L1_(2)-Pt-Co-Mn ternary intermetallic nanoparticles as high-performance oxygen-reduction electrocatalysts for practical fuel cells

The long-range periodically ordered atomic structures in intermetallic nanoparticles(INPs)can significantly enhance both the electrocatalytic activity and electrochemical stability toward the oxygen reduction reaction(ORR)compared to the disordered atomic structures in ordinary solid-solution alloy NPs.Accordingly,through a facile and scalable synthetic method,a series of carbon-supported ultrafine Pt_3Co_(x)Mn_(1-x)ternary INPs are prepared in this work,which possess the"skin-like"ultrathin Pt shells,the ordered L1_(2) atomic structure,and the high-even dispersion on supports(L1_(2)-Pt_3Co_(x)Mn_(1-x)/~SPt INPs/C).Electrochemical results present that the composition-optimized L1_(2)-Pt_3Co_(0.7)Mn_(0.3)/~SPt INPs/C exhibits the highest electrocata lytic activity among the series,which are also much better than those of the pristine ultrafine Pt/C.Besides,it also has a greatly enhanced electrochemical stability.In addition,the effects of annealing temperature and time are further investigated.More importantly,such superior ORR electrocatalytic performance of L1_(2)-Pt_3Co_(0.7)Mn_(0.3)/~SPt INPs/C are also well demonstrated in practical fuel cells.Physicochemical characterization analyses further reveal the major origins of the greatly enhanced ORR electrocata lytic performance:the Pt-Co-Mn alloy-induced geometric and ligand effects as well as the extremely high L1_(2) atomic-ordering degree.This work not only successfully develops a highly active and stable ordered ternary intermetallic ORR electrocatalyst,but also elucidates the corresponding"structure-function"relationship,which can be further applied in designing other intermetallic(electro)catalysts.

Fine mapping of two recessive genes TaFLA1 and TaSPL8 controlling flag leaf angle in bread wheat

Flag leaf angle is one of the key target traits in high yield wheat breeding.A smaller flag leaf angle reduces shading and enables plants to grow at a higher density,which increases yield.Here we identified a mutant,je0407,with an 84.34%-89.35%smaller flag leaf angle compared with the wild type.The mutant also had an abnormal lamina joint and no ligule or auricle.Genetic analysis indicated that the ligule was controlled by two recessive genes,which were mapped to chromosomes 2AS and 2DL.The mutant allele on chromosome 2AS was named Tafla1b,and it was fine mapped to a 1 Mb physical interval.The mutant allele on chr.2DL was identified as Taspl8b,a novel allele of TaSPL8 with a missense mutation in the second exon,which was used to develop a cleaved amplified polymorphic sequence marker.F3 and F4 lines derived from crosses between Jing411 and je0407 were genotyped to investigate interactions between the Tafla1b and Taspl8b alleles.Plants with the Tafla1b/Taspl8a genotype had 58.41%-82.76%smaller flag leaf angles,6.4%-24.9%shorter spikes,and a greater spikelet density(0.382 more spikelets per cm)compared with the wild type.Plants with the Tafla1a/Taspl8b genotype had 52.62%-82.24%smaller flag leaf angles and no differences in plant height or spikelet density compared with the wild type.Tafla1b/Taspl8b plants produced erect leaves with an abnormal lamina joint.The two alleles had dosage effects on ligule formation and flag leaf angle,but no significant effect on thousand-grain weight.The mutant alleles provide novel resources for improvement of wheat plant architecture.

The gene encoding flavonol synthase contributes to lesion mimic in wheat

Lesion mimic often exhibits leaf disease-like symptoms even in the absence of pathogen infection,and is characterized by a hypersensitive-response(HR)that closely linked to plant disease resistance.Despite this,only a few lesion mimic genes have been identified in wheat.In this investigation,a lesion mimic wheat mutant named je0297 was discovered,showing no alteration in yield components when compared to the wild type(WT).Segregation ratio analysis of the F_(2)individuals resulting from the cross between the WT and the mutant revealed that the lesion mimic was governed by a single recessive gene in je0297.Using Bulked segregant analysis(BSA)and exome capture sequencing,we mapped the lesion mimic gene designated as lm6 to chromosome 6BL.Further gene fine mapping using 3315 F_(2)individuals delimited the lm6 within a 1.18 Mb region.Within this region,we identified 16 high-confidence genes,with only two displaying mutations in je0297.Notably,one of the two genes,responsible for encoding flavonol synthase,exhibited altered expression levels.Subsequent phenotype analysis of TILLING mutants confirmed that the gene encoding flavonol synthase was indeed the causal gene for lm6.Transcriptome sequencing analysis revealed that the DEGs between the WT and mutant were significantly enriched in KEGG pathways related to flavonoid biosynthesis,including flavone and flavonol biosynthesis,isoflavonoid biosynthesis,and flavonoid biosynthesis pathways.Furthermore,more than 30 pathogen infection-related(PR)genes exhibited upregulation in the mutant.Corresponding to this expression pattern,the flavonoid content in je0297 showed a significant decrease in the 4^(th)leaf,accompanied by a notable accumulation of reactive oxygen,which likely contributed to the development of lesion mimic in the mutant.This investigation enhances our comprehension of cell death signaling pathways and provides a valuable gene resource for the breeding of disease-resistant wheat.

Separation of n-heptane and tert-butanol by ionic liquids based on COSMO-SAC model

In the process of liquid-liquid extraction,it is necessary to look for green solvents as extractants.Ionic liquids have been studied as extractants due to their green recyclability in recent years.The infinite dilution activity coefficients of 100 ionic liquids with a combination of 10 cations and 10 anions were calculated by COSMO-SAC model,and theσ-profiles were plotted.The distribution coefficient and separation coefficient of n-heptane+tert-butanol+ILs were determined.[OMIM][OTF],[HMIM][OTF]and[BMIM][OTF]were selected as solvents for this study.The interaction energy,bond length and charge density of ionic liquids with tert-butanol were calculated by quantum chemistry calculation method.According to these results,the rationality of selected ionic liquids as extractants could be analyzed from the molecular level.At 298.15 K and 101.325 kPa,the liquid-liquid equilibrium data of the ternary system{n-heptane+tert-butanol+[OMIM][OTF],nheptane+tert-butanol+[BMIM][OTF],n-heptane+tert-butanol+[HMIM][OTF]}were measured.The distribution coefficient and separation coefficient for judging the extraction effect were obtained.The NRTL model was used to correlate liquid-liquid equilibrium experimental data,and correlation result proved that the correlated and experimental data had a good correlation.The research on ionic liquids is of great significance to the development of green and sustainable chemical industry.

Jacobi-Sobolev Orthogonal Polynomialsand Spectral Methods for Elliptic Boundary Value Problems

Generalized Jacobi polynomials with indexes α,β∈ R are introduced and some basic properties are established. As examples of applications,the second- and fourth-order elliptic boundary value problems with Dirichlet or Robin boundary conditions are considered,and the generalized Jacobi spectral schemes are proposed. For the diagonalization of discrete systems,the Jacobi-Sobolev orthogonal basis functions are constructed,which allow the exact solutions and the approximate solutions to be represented in the forms of infinite and truncated Jacobi series. Error estimates are obtained and numerical results are provided to illustrate the effectiveness and the spectral accuracy.

Efficacy and safety of human umbilical cord-derived mesenchymal stem cells in the treatment of refractory immune thrombocytopenia:a prospective,single arm,phase I trial

Patients with refractory immune thrombocytopenia(ITP)frequently encounter substantial bleeding risks and demonstrate limited responsiveness to existing therapies.Umbilical cord-derived mesenchymal stem cells(UC-MSCs)present a promising alternative,capitalizing on their low immunogenicity and potent immunomodulatory effects for treating diverse autoimmune disorders.This prospective phase I trial enrolled eighteen eligible patients to explore the safety and efficacy of UC-MSCs in treating refractory ITP.The research design included administering UC-MSCs at escalating doses of 0.5×10^(6)cells/kg,1.0×10^(6)cells/kg,and 2.0×10^(6)cells/kg weekly for four consecutive weeks across three cohorts during the dose-escalation phase,followed by a dose of 2.0×10^(6)cells/kg weekly for the dose-expansion phase.Adverse events,platelet counts,and changes in peripheral blood immunity were monitored and recorded throughout the administration and follow-up period.Ultimately,12(with an addition of three patients in the 2.0×10^(6)cells/kg group due to dose-limiting toxicity)and six patients were enrolled in the dose-escalation and dose-expansion phase,respectively.Thirteen patients(13/18,72.2%)experienced one or more treatment emergent adverse events.Serious adverse events occurred in four patients(4/18,22.2%),including gastrointestinal hemorrhage(2/4),profuse menstruation(1/4),and acute myocardial infarction(1/4).The response rates were 41.7%in the dose-escalation phase(5/12,two received 1.0×10^(6)cells/kg per week,and three received 2.0×10^(6)cells/kg per week)and 50.0%(3/6)in the dose-expansion phase.The overall response rate was 44.4%(8/18)among all enrolled patients.To sum up,UC-MSCs are effective and well tolerated in treating refractory ITP(ClinicalTrials.gov ID:NCT04014166).

Cubature Formula and Interpolation on the Cubic Domain

Several cubature formulas on the cubic domains are derived using the discrete Fourier analysis associated with lattice tiling, as developed in [10]. The main results consist of a new derivation of the Gaussian type cubature for the product Chebyshev weight functions and associated interpolation polynomials on [-1,1]^2, as well as new results on [-1, 1]^3. In particular, compact formulas for the fundamental interpolation polynomials are derived, based on n3/4 ＋ O（n^2） nodes of a cubature formula on [-1,1]^3.

C1-Conforming Quadrilateral Spectral Element Method for Fourth-Order Equations

This paper is devoted to Professor Benyu Guo's open question on the C1-conforming quadrilateral spectral element method for fourth-order equations which has been endeavored for years. Starting with generalized Jacobi polynomials on the reference square, we construct the C1-conforming basis functions using the bilinear mapping from the reference square onto each quadrilateral element which fall into three categories-interior modes, edge modes, and vertex modes. In contrast to the triangular element, compulsively compensatory requirements on the global C1-continuity should be imposed for edge and vertex mode basis functions such that their normal derivatives on each common edge are reduced from rational functions to polynomials, which depend on only parameters of the common edge. It is amazing that the C1-conforming basis functions on each quadrilateral element contain polynomials in primitive variables, the completeness is then guaranteed and further confirmed by the numerical results on the Petrov-Galerkin spectral method for the non-homogeneous boundary value problem of fourth-order equations on an arbitrary quadrilateral. Finally, a C1-conforming quadrilateral spectral element method is proposed for the biharmonic eigenvalue problem, and numerical experiments demonstrate the effectiveness and efficiency of our spectral element method.

Identification of a von Willebrand factor type A protein affecting both grain and flag leaf morphologies in wheat

Dear Editor,The world faces unprecedented challenges for crop yield improvement to feed an expanding human population under limited agricultural resources and an increasingly erratic climate(Wheeler and von Braun,2013).Bread wheat is one of the most widely cultivated cereal crops,with both grain and flag leaf morphologies determining final yield potential(Xie et al.,2015;Zanella et al.,2023).Candidate genes affecting these traits are therefore highly desirable targets for breeding programs.

EFFICIENT SPECTRAL METHODS FOR EIGENVALUE PROBLEMS OF THE INTEGRAL FRACTIONAL LAPLACIAN ONABALLOFANYDIMENSION

An efficient spectral-Galerkin method for eigenvalue problems of the integral fractional Laplacian on a unit ball of any dimension is proposed in this paper.The symmetric positive definite linear system is retained explicitly which plays an important role in the numerical analysis.And a sharp estimate on the algebraic system's condition number is established which behaves as N4s with respect to the polynomial degree N,where 2s is the fractional derivative order.The regularity estimate of solutions to source problems of the fractional Laplacian in arbitrary dimensions is firstly investigated in weighted Sobolev spaces.Then the regularity of eigenfunctions of the fractional Laplacian eigenvalue problem is readily derived.Meanwhile,rigorous error estimates of the eigenvalues and eigenvectors are ob-tained.Numerical experiments are presented to demonstrate the accuracy and efficiency and to validate the theoretical results.

Sex-specific impact on disease outcome and the mutational landscape in essential thrombocythemia:A retrospective cohort study

To the Editor:Male sex has been confirmed to be an independent risk factor for survival in patients with essential thrombocythemia(ET).[1,2]Sexual dimorphism significantly contributes to patient heterogeneity,and adopting a sex-informed perspective has emerged as a pioneering paradigm in the field of precision medicine.Investigating the spectrum of sex disparities among patients diagnosed with ET holds substantial scientific justification.Furthermore,sex influences the presentation,disease phenotypes,symptom expression,and clinical outcomes of classical Philadelphia chromosome-negative myeloproliferative neoplasm(MPN).[3,4]The objective of our study was to comprehensively elucidate the impact of sex on ET by exploring disease genotype and phenotype as well as clinical outcomes.

Plant genome editing using xCas9 with expanded PAM compatibility

CRISPR/Cas enables robust genome editing and has revolution-ized both functional genomics and crop breeding.The specificity of Cas-directed DNA cleavage is strictly determined by a chimeric single guide RNA(SgRNA)and a short protospacer adjacent motif(PAM)in the genome(Cong et al,2013;Zetsche et al,2015).The widely used Cas9 from Streptococcus pyogenes(SpCas9)generally recognizes the canonical NGG PAM(where N indicates any nucleicacid base)(Miao et al.,2013;Ma et al,2015),making many regionsuntargetable by Cas9.SpCas9 VQR and VRER variants,which recog-nize the non-canonical PAM sequences of NGA and NGCG,respectively,have been used to expand targetable sequences in plants(Hu et al.,2016).In addition,the applications of other Cas endonucleases such as SaCas9(Staphylococcus aureus Cas9)(Ran et al..2015).

A perspective on influences of cathode material degradation on oxygen transport resistance in low Pt PEMFC

A large-scale industrial application of proton exchange membrane fuel cells(PEMFCs)greatly depends on both substantial cost reduction and continuous durability enhancement.However,compared to effects of material degradation on apparent activity loss,little attention has been paid to influences on the phenomena of mass transport.In this review,influences of the degradation of key materials in membrane electrode assemblies(MEAs)on oxygen transport resistance in both cathode catalyst layers(CCLs)and gas diffusion layers(GDLs)are comprehensively explored,including carbon support,electrocatalyst,ionomer in CCLs as well as carbon material and hydrophobic polytetrafluoroethylene(PTFE)in GDLs.It is analyzed that carbon corrosion in CCLs will result in pore structure destruction and impact ionomer distribution,thus affecting both the bulk and local oxygen transport behavior.Considering the catalyst degradation,an eventual decrease in electrochemical active surface area(ECSA)definitely increases the local oxygen transport resistance since a decrease in active sites will lead to a longer oxygen transport path.It is also noted that problems concerning oxygen transport caused by the degradation of ionomer chemical structure in CCLs should not be ignored.Both cation contamination and chemical decomposition will change the structure of ionomer,thus worsening the local oxygen transport.Finally,it is found that the loss of carbon and PTFE in GDLs lead to a higher hydrophilicity,which is related to an occurrence of water flooding and increase in the oxygen transport resistance.

Exploration of the oxygen transport behavior in non-precious metal catalyst-based cathode catalyst layer for proton exchange membrane fuel cells

High cost has undoubtedly become the biggest obstacle to the commercialization of proton exchange membrane fuel cells(PEMFCs),in which Pt-based catalysts employed in the cathodic catalyst layer(CCL)account for the major portion of the cost.Although nonprecious metal catalysts(NPMCs)show appreciable activity and stability in the oxygen reduction reaction(ORR),the performance of fuel cells based on NPMCs remains unsatisfactory compared to those using Pt-based CCL.Therefore,most studies on NPMC-based fuel cells focus on developing highly active catalysts rather than facilitating oxygen transport.In this work,the oxygen transport behavior in CCLs based on highly active Fe-N-C catalysts is comprehensively explored through the elaborate design of two types of membrane electrode structures,one containing low-Pt-based CCL and NPMCbased dummy catalyst layer(DCL)and the other containing only the NPMC-based CCL.Using Zn-N-C based DCLs of different thickness,the bulk oxygen transport resistance at the unit thickness in NPMC-based CCL was quantified via the limiting current method combined with linear fitting analysis.Then,the local and bulk resistances in NPMC-based CCLs were quantified via the limiting current method and scanning electron microscopy,respectively.Results show that the ratios of local and bulk oxygen transport resistances in NPMCbased CCL are 80%and 20%,respectively,and that an enhancement of local oxygen transport is critical to greatly improve the performance of NPMC-based PEMFCs.Furthermore,the activity of active sites per unit in NPMCbased CCLs was determined to be lower than that in the Pt-based CCL,thus explaining worse cell performance of NPMC-based membrane electrode assemblys(MEAs).It is believed that the development of NPMC-based PEMFCs should proceed not only through the design of catalysts with higher activity but also through the improvement of oxygen transport in the CCL.

Precise Modifications of Both Exogenous and Endogenous Genes in Rice by Prime Editing

Dear Editor,Harnessing genetic diversity and the introduction of elite alleles from wild relatives or landraces into commercial cultivars has been a major goal in crop breeding programs.Precise modification of the plant genome through clustered regularly interspaced short palindromic repeat(CRISPR)/CRISPR-associated protein(Cas)(CRISPR/Cas)-mediated homology-directed repair(HDR)offers a great promise to introduce elite alleles from wild relatives or landraces into commercialized cultivars in the short term.

Toward Precision Genome Editing in Crop Plants

Precision genome editing through homology-directed repair(HDR)in plants remains very challenging due to the innately low occurrence of HDR and obstacles in the delivery of sufficient donor repair template(DRT)into plant cells.For single-base substitution,cytidine or adenine base editors have been used successfully in crop plants in recent years.However,base editing is constrained by the distance between the targeted base and PAM motif and cannot install predefined transversion mutations or insertions and deletions(indels).Here,we briefly summarize the strategies reported so far for precision genome editing in plants.Based on the recently developed prime editing strategy,which enables gene replacement without double-strand breaks(DSBs)or DRT in both human cells and plants,we provide our perspectives on exploiting diverse strategies to achieve precise targeted gene/allele replacement toward crop improvement and resilience for sustainable agricultural development.

Multiplex precision gene editing by a surrogate prime editor in rice

Dear Editor,Development of a multiplex precision gene editing system is highly desirable for pyramiding beneficial alleles in crop improve-ment.Prime editing is a newly developed genome-editing tool that can precisely enable the installation of all 12 nucleotide sub-stitutions,short insertions,and deletions without exogenous DNA donor repair template and double-strand breaks(Anzalone et al.,2019).Among the prime editing systems,prime editor 3(PE3),which consists of a prime editing guide RNA(pegRNA)and an additional nicking single guide RNA(sgRNA)to nick the non-edited strand,enhances editing efficiency.

Intracavity biosensor based on the Nd:YAG waveguide laser: tumor cells and dextrose solutions

This work demonstrates the Nd:YAG waveguide laser as an efficient platform for the bio-sensing of dextrose solutions and tumor cells. The waveguide was fabricated in an Nd:YAG crystal with the cooperation of ultrafast laser writing and ion irradiation. The laser oscillation in the Nd:YAG waveguide is ultrasensitive to the external environment of the waveguide. Even a weak disturbance leads to a large variation of the output power of the laser.According to this feature, an Nd:YAG waveguide coated with graphene and WSe_2 layers is used as substrate for the microfluidic channel. When the microflow crosses the Nd:YAG waveguide, the laser oscillation in the waveguide is disturbed and induces fluctuation of the output laser. According to the fluctuation, the microflow is detected with a sensitivity of 10 mW/RIU.

Efficient Hermite Spectral-Galerkin Methods for Nonlocal Diffusion Equations in Unbounded Domains

In this paper,we develop an efficient Hermite spectral-Galerkin method for nonlocal diffusion equations in unbounded domains.We show that the use of the Hermite basis can de-convolute the troublesome convolutional operations involved in the nonlocal Laplacian.As a result,the“stiffness”matrix can be fast computed and assembled via the four-point stable recursive algorithm with O(N^(2))arithmetic operations.Moreover,the singular factor in a typical kernel function can be fully absorbed by the basis.With the aid of Fourier analysis,we can prove the convergence of the scheme.We demonstrate that the recursive computation of the entries of the stiffness matrix can be extended to the two-dimensional nonlocal Laplacian using the isotropic Hermite functions as basis functions.We provide ample numerical results to illustrate the accuracy and efficiency of the proposed algorithms.