CRISPR/Cas9-mediated targeted mutation reveals a role for AN4 rather than DPL in regulating venation formation in the corolla tube of Petunia hybrida

Venation is a common anthocyanin pattern displayed in flowers that confers important ornamental traits to plants.An anthocyanin-related R2R3-MYB transcription factor,DPL,has been proposed to regulate corolla tube venation in petunia plants.Here,however,we provide evidence redefining the role of DPL in petunia.A CRISPR/Cas9-mediated mutation of DPL resulted in the absence of the vein-associated anthocyanin pattern above the abaxial surface of the flower bud,but not corolla tube venation,thus indicating that DPL did not regulate the formation of corolla tube venation.Alternately,quantitative real-time PCR analysis demonstrated that the spatiotemporal expression pattern of another R2R3-MYB gene,AN4,coincided with the formation of corolla tube venation in petunia.Furthermore,overexpression of AN4 promoted anthocyanin accumulation by increasing the expression of anthocyanin biosynthesis genes.CRISPR/Cas9-mediated mutation of AN4 led to an absence of corolla tube venation,suggesting that this gene in fact determines this key plant trait.Taken together,the results presented here redefine the prime regulator of corolla tube venation,paving the way for further studies on the molecular mechanisms underlying the various venation patterns in petunia.

Analysis Method of Transient Temperature Field for Fuel Tank ofHigh-Altitude Large UAV

Based on the analysis of factors affecting transient temperature field of aircraft fuel tank and coupled heat transfer mechanism, a mathematical model of transient coupled heat transfer, including the dynamic- change of fuel quality, the internal heat transfer, the external aerodynamic convection and the radiation heat transfer, is established. Taking the aerodynamic convection and radiation heat transfer outside the tank as the third kinds of thermal boundary conditions for the thermal analysis of the fuel tank, calculation of internal and external coupling heat of fuel tank is decoupled. Ther^nal network method combined with hierarchical dynamic- grid is used to deal with the fuel consumption, and carry on the heat transfer analysis of the fuel tank. The numerical method for the transient temperature field of aircraft fuel tank is established. Through the simulation calculation, the transient temperature distribution of the fuel tank under different flight conditions is obtained, and the influence of the fuel mass and the external thermal environment on the temperature field is analyzed.

Threshold of Soil pH for Occurrence of Tobacco Bacterial Wilt in Henan Province

[Objective]The paper was to study the relationship between spatial distribution characteristics of soil p H and bacterial wilt in tobacco-growing area in Henan Province.[Method]The 21 tobacco-growing fields infected by bacterial wilt and 91 tobacco-growing fields with no cases were selected from Henan Province,and the pH of fields was determined.[Result]Bacterial wilt mainly occurred in the tobacco-growing fields in Luoshan,Pingqiao,Queshan,Biyang,Suiping,and Xiping,and the soil pH mainly ranged from 5.5 to 6.5(accounted for 84.75%of total surveyed tobacco fields);bacterial wilt had not been found in tobacco-growing fields in Tanghe,Zhengyang,Shangcai,Sheqi,Wuyang and Chenqu,and the soil pH mainly ranged from 6.5 to 7.0(accounted for 81.25%of total surveyed tobacco fields).There were significant differences in soil pH between the fields with and without bacterial wilt,and soil pH 6.5 could be regarded as the threshold for the occurrence of tobacco bacterial wilt in Henan Province.There was extremely significantly positive linear correlation between soil p H and latitude(y=0.7375 x-17.799,R2=0.386,P<0.01).The geographical boundary of soil pH 6.5 was roughly 33°N,and bacterial wilt was less likely to occur in the north tobacco-growing areas of the boundary.[Conclusion]The study will provide a scientific basis for the prevention and control of tobacco bacterial wilt in Henan.

Effects of Early Infection of Tobacco Mosaic Virus on Photosynthetic Proteins and Its Control

[Objectives] This study was conducted to explore the optimal period of TMV control and the physiological sites that interfere with TMV infection. [Methods] Proteome analysis was performed on the host tissues(tobacco plants) at different time periods of viral infection, to verify the changes in the expression of differential protein genes and N and PR1-a in the photosynthetic pathway and porphyrin metabolism and chlorophyll metabolism pathways in proteome; and the tobacco plants were treated with different preparations. [Results] The expression levels of N and PR1-a in the tobacco leaves treated with preparation B reached the highest level, and the effects on the expression levels of the differential protein genes were also the most significant. The control effects of the preparations were tested by the half-leaf method, and the results showed that preparation B had a significant control effect against the early infection of the virus.[Conclusions] This study lays a foundation for the prevention and control of tobacco mosaic virus on crops.

Effects of in-situZrB_2 nanoparticles and scandium on microstructure and mechanical property of 7N01 aluminum alloy

In this study, the in-situ synthesized ZrB_(2) nanoparticles and rare earth Sc were introduced to enhance the strength and ductility of 7N01 aluminum alloy, via the generation of high-melting and uniform nanodispersoids. The microstructure and mechanical property evolution of the prepared composites and the interaction between ZrB_(2) and Sc were studied in detail. The microstructure investigation shows that the introduction of rare earth scandium(Sc) can promote the distribution of ZrB_(2) nanoparticles, by improving their wettability to the Al melt. Meanwhile, the addition of rare earth Sc also modifies the coarse Al Zn Mg Mn Fe precipitated phases, refines the matrix grains and generates high-melting Al_3(Sc,Zr)/Al_3Sc nanodispersoids. Tensile tests of the composites show that with the combinatorial introduction of ZrB_(2) and Sc, the strength and ductility of the composites are improved simultaneously compared with the corresponding 7N01 alloy, ZrB_(2) /7N01 composite and Sc/7N01 alloy. And the optimum contents of ZrB_(2) and Sc are 3 wt% and 0.2 wt% in this study. The yield strength, ultimate strength and elongation of(3 wt% ZrB_(2) +0.2 wt% Sc)/7N01 composite are 477 MPa, 506 MPa and 9.8%, increased about 18.1%, 12.2%and 38% compared to 7N01 alloy. Furthermore, the cooperation strengthening mechanisms of ZrB_(2) and Sc are also discussed.

A genome-wide association study uncovers that TaPI4K-2A regulates pre-harvest sprouting in wheat

Dear Editor,Pre-harvest sprouting(PHS)is a major challenge to cereal crop production in areas with frequent rainfall at harvest time and has significant effects on grain yield and end-use quality(Lang et al.,2021).PHS is quantified by the dormancy/germination ratio of seeds and is largely regulated by two opposing phytohormones,abscisic acid(ABA)and gibberellin(GA)(Tai et al.,2021).ABA induces dormancy and suppresses PHS,whereas GA exerts the opposite effects(Finkelstein et al.,2008).Because of the complexity of the genome,only a few genes involved in regulation of PHS have been identified in wheat,and the underlying molecular regulatory mechanisms of PHS remain largely unknown in this species.

辐射输运方程的统一气体动理学格式

辐射输运方程的数值模拟在天体物理、武器物理和惯性约束与磁约束聚变等研究中都起着非常重要的作用.在实际问题中,背景介质的不透明度系数决定了辐射光子在其中的传输行为.光性薄(不透明度系数小)的介质对辐射光子是透明的,光子与背景介质的相互作用弱,光子传输具有输运传播性质;而光性厚(不透明度系数大)的介质对辐射光子是不透明的,光子与背景介质的相互作用强,光子传输具有扩散性质.因此在辐射输运方程的计算中,如何设计既能得到光子输运传播性质又能捕捉光子扩散传播性质的渐近保持离散格式是目前一个非常活跃和前沿的研究方向.本文简要介绍近几年在辐射输运方程的渐近保持统一气体动理学格式(unified gas kinetic scheme,UGKS)研究方面的进展.本文主要以灰体辐射输运方程为例,详细介绍UGKS的构造方法并给出其渐近分析.同时,结合角度有限元方法和球谐函数展开的方法,介绍如何减弱/去除基于离散纵标法的UGKS具有射线效应的问题,以及相应的改进渐近保持格式.此外,也介绍了将渐近保持的UGKS应用拓展到考虑流体运动的完全辐射流体力学方程组.最后,用一些数值例子验证了格式的渐近保持性和保正性等性质.

光学相干层析技术在朱墨时序检验中的初步研究

朱墨时序一直以来都是法庭科学文件检验领域中的难题之一。鉴于此,首先利用一种新型的光学断层成像技术,即光学相干层析(OCT)技术对朱墨时序进行检验,该技术具有原位、无损、快速和高分辨率等优点。利用一套中心波长为900nm的频域OCT系统对三种不同类型的朱墨时序样本进行OCT成像检验,比较不同类型样品朱墨交叉区域的二维断层OCT图像的特征差异,并分析特征差异产生的原因。初步实验研究结果表明,利用OCT技术可以为朱墨时序的判断提供一种有效的处理手段,为补充和丰富现有的方法体系奠定基础。

中国沿海洛氏角毛藻复合群的多样性组成及地理分布

洛氏角毛藻复合群(Chaetoceros lorenzianus complex)指具有与洛氏角毛藻相似形态学特征的物种集合,它们广泛分布于全球近岸水域。近年国际上关于该复合群的分类学研究取得新进展,而我国相关研究仍较为滞后。为了弄清我国沿海洛氏角毛藻复合群的物种多样性,明确物种信息,厘清种间界限,为相关研究提供准确的物种鉴定依据,本研究陆续在中国沿海建立了该复合群的332个单克隆培养株系,利用光学显微镜、扫描电镜和透射电镜进行了较为详尽的形态学研究,基于核糖体大亚基编码基因D1–D3区序列,构建了分子系统学关系。结果表明其形态聚类与分子系统学结论相一致,显示我国洛氏角毛藻复合群具有较高的物种多样性,共鉴定到5个物种,分别是并基角毛藻(C.decipiens)、优美角毛藻(C.elegans)、平孢角毛藻(C.laevisporus)、曼纳角毛藻(C.mannaii)和稀树角毛藻(C.pauciramosus)。研究表明传统认知的光镜下特征,如群体特征、角毛走势等易变化,其分类学价值需谨慎应用。角毛的超微结构,如角毛孔纹的形状、大小、密度等是有效的种间区别特征,休眠孢子亦是重要的物种识别依据。并基角毛藻和平孢角毛藻在我国沿岸的分布范围最为广泛,而稀树角毛藻的分布较为有限。

Synthesis of monolithic carbon aerogels with high mechanical strength via ambient pressure drying without solvent exchange

A simple,fast and cost-effective method for monolithic carbon aerogels(CAs) preparation was proposed through sol-gel polycondensation of resorcinol with fo rmaldehyde in a basic aqueous solution followed by ambient pressure drying without solvent exchange,and carbonization.The microstructure and network strength of CAs were tailored by adju sting the catalyst concentration([resorcinol]/[sodium carbonate] in the range of 300-2000),water content([deionized water]/[resorcinol] equals to 17 and 24,respectively),and gelation temperature(Tgel in the range of 30-90℃).Resultantly,the CAs with a wide range of density(0.30-1.13 g/cm3),high specific surface area(465-616 m2/g),high compressive strength(6.5-147.4 MPa)and low thermal conductivity(0.065-0.120 W·m-1 K-1) were obtained in this work.Moreover,the largesized CAs(100×100×20 mm3) can also be prepared by this method since the formed robust skeleton network can resist shrinkage/collapse of pore structure and prevent cracking during drying.The improved mechanical strength and monolithic forming abilities could be mainly attributed to the uniform arrangement of carbon particles and pores,fine particle size,abundant network structure and enhanced particle neck.

The genome of the recretohalophyte Limonium bicolor provides insights into salt gland development and salinity adaptation during terrestrial evolution

Halophytes have evolved specialized strategies to cope with high salinity.The extreme halophyte sea lavender(Limonium bicolor)lacks trichomes but possesses salt glands on its epidermis that can excrete harmful ions,such as sodium,to avoid salt damage.Here,we report a high-quality,2.92-Gb,chromosome-scale L.bicolor genome assembly based on a combination of Illumina short reads,single-molecule,real-time long reads,chromosome conformation capture(Hi-C)data,and Bionano genome maps,greatly enriching the genomic information on recretohalophytes with multicellular salt glands.Although the L.bicolor genome contains genes that show similarity to trichome fate genes from Arabidopsis thaliana,it lacks homologs of the decision fate genes GLABRA3,ENHANCER OF GLABRA3,GLABRA2,TRANSPARENT TESTA GLABRA2,and SIAMESE,providing a molecular explanation for the absence of trichomes in this species.We identified key genes(LbHLH and LbTTG1)controlling salt gland development among classical trichome homologous genes and confirmed their roles by showing that their mutations markedly disrupted salt gland initiation,salt secretion,and salt tolerance,thus offering genetic support for the long-standing hypothesis that salt glands and trichomes may share a common origin.In addition,a whole-genome duplication event occurred in the L.bicolor genome after its divergence from Tartary buckwheat and may have contributed to its adaptation to high salinity.The L.bicolor genome resource and genetic evidence reported in this study provide profound insights into plant salt tolerance mechanisms that may facilitate the engineering of salt-tolerant crops.

Pers onal In come Tax Reform in China in 2018 and Its Impact on Income Distribution

In the context of personal income tax(PIT)reform in China in 2018,this paper examines some of the major issues of concern regarding the reform and income distribution.Using the China Personal Income Tax Micro-simulation model,the paper compares the differences between the 2011 and 2018 PIT systems,and finds that residents relying on different income sources may face a large degree of real tax rate change.Once the tax system is altered to PIT 2018,the coverage of PIT for wage earners will decrease from 46.9 to 23.4 percent,the income redistributive effect will drop from 1.95 to 1.22 percent and the PITs role in fiscal revenue will also be negatively affected.Nevertheless,if individual income continues to grow,the share of PIT in fiscal revenue is expected to return to the 2018 level in 2022,but its income redistribution function is difficult to recover in the short term.The paper finds that the effect of PIT on income distribution depends on the tax structure.Gradual transition to an"entirely comprehensive"tax system when conditions are appropriate will achieve better income redistribution results at a lower average tax rate.

Homological Epimorphisms, Compactly Generated t-Structures and Gorenstein-Projective Modules

The aim of this paper is two-fold.Given a recollement(T′,T,T′′,i*,i_*,i~!,j!,j*,j*),where T′,T,T′′are triangulated categories with small coproducts and T is compactly generated.First,the authors show that the BBD-induction of compactly generated t-structures is compactly generated when i*preserves compact objects.As a consequence,given a ladder(T′,T,T′′,T,T′) of height 2,then the certain BBD-induction of compactly generated t-structures is compactly generated.The authors apply them to the recollements induced by homological ring epimorphisms.This is the first part of their work.Given a recollement(D(B-Mod),D(A-Mod),D(C-Mod),i*,i_*,i~!,j!,j*,j_*) induced by a homological ring epimorphism,the last aim of this work is to show that if A is Gorenstein,AB has finite projective dimension and j! restricts to D^b(C-mod),then this recollement induces an unbounded ladder(B-Gproj,A-Gproj,C-Gproj) of stable categories of finitely generated Gorenstein-projective modules.Some examples are described.

Synchronization of switched Boolean networks with impulsive effects

This paper studies the state/output synchronization of switched Boolean networks （SBNs） with impulsive effects via the algebraic state space representation （ASSR） approach. First, an algebraic form is established for SBNs with impulsive effects via ASSR. Second, based on the algebraic form, some necessary and sufficient conditions are presented for the state/output synchronization of SBNs with impulsive effects under arbitrary switching signals. Third, two special kinds of switching signals, that is, free switching signal and feedback switching signal, are considered for the state synchroniza-tion of SBNs with impulsive effects. Finally, two illustrative examples are worked out to show the effectiveness of the obtained results.

Preparative separation of high-purity troxerutin and related substances from mother liquor of troxerutin by silica gel column chromatography and semi-preparative liquid chromatography

Troxerutin(TRO)is a mixture of semi-synthetic flavonoids prepared by hydroxyethylation of rutin,and it is commonly used for the treatment of cerebrovascular diseases.The main active ingredient is trishydroxyethyl rutin.The mother liquor of TRO contains a lot of TRO and other derivatives of hydroxyethylated rutin.In order to make full use of the mother liquor of TRO,an efficient method was developed for recovering high-purity TRO from mother liquor of TRO by combining silica gel column chromatography with semi-preparative liquid chromatography.In the silica gel column chromatographic separation,the ratio of silica gel to sample and eluent composition were investigated to obtain optimum separation effect.The results showed that when the ratio of silica gel to sample was 50,and acetone–ethyl acetate–water–glacial acetic acid(10:10:3:1,v/v/v/v)was used as the eluent,the separation effect of TRO and adjacent impurities was good.Moreover,150 g of TRO with a purity of 80%could be obtained from 1 kg of mother liquor of TRO by the silica gel column chromatographic separation,and the results were consistent with the quality standard of TRO raw material.Subsequently,the semi-preparative HPLC was performed,and 100 g TRO with a purity of up to 98%(w/w)was obtained.Meanwhile,tetrahydroxyethylrutin and tetrahydroxyethylquercetin with purity greater than 98%were obtained.This work proposed the separation and preparation of TRO with high-purity from the production waste of TRO for the first time,which had certain environmental benefits and economic benefits.

冷战后美国“中国观”的演变:内容与动因

冷战后至今,美国的“中国观”经历了从克林顿政府至拜登政府的四个阶段演变,呈现出日益消极的趋势。当前,在中美战略竞争加剧的背景下,美国对中国“战略竞争者”的定位再度清晰。从内容上看,美国对中国的战略目标、未来发展方向以及与国际秩序的关系的认识发生了三重转变。这些转变源于中美实力对比的变化、美国根深蒂固的意识形态偏见,以及美国两党对华强硬新共识的形成。美国的“中国观”影响了美国的对华政策以及中美关系,厘清美国的“中国观”,有助于我国一方面进行有理有利有力的反击,另一方面推进中美在具体问题上增强互信与共识、管控分歧、防止冲突升级,具有重要的现实意义。

Toripalimab in advanced biliary tract cancer

Gemcitabine combined with platinum/fluorouracil drugs is the standard firstline treatment for advanced biliary tract cancers(BTCs).We explored the safety and efficacy of toripalimab plus gemcitabine and S-1(GS)as the first-line treatment for advanced BTCs.At a one-sided significance level of 0.025,a total of 50 patients could provide 80%power to show the efficacy at targeted progression-free survival(PFS)rate at 6 months of 70%versus 40%for the combined treatment.This single-arm,phase II study enrolled 50 patients with advanced BTCs who previously received no systemic treatment.The regimen was as follows:toripalimab(240 mg,i.v.,d1),gemcitabine(1,000 mg/m2,i.v.,d1 and d8),and S-1(40–60 mg bid p.o.,d1–14,Q21d).The primary endpoint was progression-free survival.The secondary endpoints included overall survival(OS),objective response rate(ORR),duration of response(DOR),and safety.The associations between response with PDL1 expression,tumor mutational burden(TMB),and genetic variations were explored.Patients were enrolled from January 2019 to August 2020,with a median follow-up time of 24.0 months(IQR:4.3–31.0 months).