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RNA silencing:From discovery and elucidation to application and perspectives

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Journal of Integrative Plant Biology 2022年第2期64卷 476-498页

作者： jian-hua zhao Hui-Shan Guo State Key Laboratory of Plant Genomics Institute of Microbiologythe Chinese Academy of SciencesBeijing100101 China CAS Center for Excellence in Biotic Interactions University of the Chinese Academy of SciencesBeijing100049 China

RNA silencing(or RNA interference,RNAi)is a conserved mechanism for regulating gene expression in *** discovery of natural trans-kingdom RNAi indicated that small RNAs act as signaling molecules and enable communication between organisms in different *** phenomenon and potential mechanisms of trans-kingdom RNAi are among the most exciting research *** better understand trans-kingdom RNAi,we review the history of the discovery and elucidation of RNAi *** on canonical RNAi mechanisms,we summarize the major points of divergence around RNAi pathways in the main eukaryotes’kingdoms,including plants,animals,and *** review the representative incidents associated with the mechanisms and applications of trans-kingdom RNAi in crop protection,and discuss the critical factors that should be considered to develop successful trans-kingdom RNAi-based crop protection strategies.

关键词： crop protection gene expression RNA silencing small RNAs trans-kingdom RNAi

Numerical simulation study on the mold strength of magnetic mold casting based on a coupled electromagnetic-structural method

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China Foundry 2024年第5期21卷 577-587页

作者： Wei-li Peng jian-hua zhao Cheng Gu Ya-jun Wang College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China National Key Laboratory of Advanced Casting Technologies Chongqing UniversityChongqing 400044China

The properties of the magnetic mold in magnetic mold casting directly determine the quality of the final cast *** this study,the magnetic mold properties in magnetic mold casting,were studied utilizing a coupled electromagnetic-structural method through numerical *** study investigated key factors including equivalent stress,the distribution of tensile and compressive stresses,and the area ratio of tensile *** compared molds made entirely of magnetic materials with those made partially of magnetic *** results indicate that as current increases from 4 A to 8 A,both the initial magnetic mold and the material-replaced magnetic mold initially show an increasing trend in equivalent stress,tensile-compressive stress,and the area ratio of tensile stress,peaking at 6 A before *** material replacement,the area ratio of tensile stress at 6 A decreases to 19.84%,representing a reduction of 29.72%.Magnetic molds comprising a combination of magnetic and non-magnetic materials exhibit sufficient strength and a reduced area ratio of tensile stress compared to those made entirely from magnetic *** study provides valuable insights for optimizing magnetic mold casting processes and offers practical guidance for advancing the application of magnetic molds.

关键词： magnetic mold casting coupled electromagnetic-structural method numerical simulation stress analysis

Influence of Self-excited Vibrating Cavity Structure on Droplet Diameter Characteristics of Twin-fluid Nozzle

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Chinese Journal of Mechanical Engineering 2018年第4期31卷 192-201页

作者： Bo Chen Dian-Rong Gao Shao-Feng Wu jian-hua zhao School of Mechanical Engineering Yanshan University School of Mechanical Engineering Hangzhou Dianzi University State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University

It is a great challenge to find effective atomizing technology for reducing industrial pollution; the twin-fluid atomizing nozzle has drawn great attention in this field recently. Current studies on twin-fluid nozzles mainly focus on droplet breakup and single droplet characteristics. Research relating to the influences of structural parameters on the droplet diameter characteristics in the flow field is scarcely available. In this paper, the influence of a self-excited vibrating cavity structure on droplet diameter characteristics was investigated. Twin-fluid atomizing tests were performed by a self-built open atomizing test bench, which was based on a phase Doppler particle analyzer(PDPA). The atomizing flow field of the twin-fluid nozzle with a self-excited vibrating cavity and its absence were tested and analyzed. Then the atomizing flow field of the twin-fluid nozzle with different self-excited vibrating cavity structures was *** experimental results show that the structural parameters of the self-excited vibrating cavity had a great effect on the breakup of large droplets. The Sauter mean diameter(SMD) increased with the increase of orifice diameter or orifice depth. Moreover, a smaller orifice diameter or orifice depth was beneficial to enhancing the turbulence around the outlet of nozzle and decreasing the SMD. The atomizing performance was better when the orifice diameter was2.0 mm or the orifice depth was 1.5 mm. Furthermore, the SMD increased first and then decreased with the increase of the distance between the nozzle outlet and self-excited vibrating cavity, and the SMD of more than half the atomizing flow field was under 35 μm when the distance was 5.0 mm. In addition, with the increase of axial and radial distance from the nozzle outlet, the SMD and arithmetic mean diameter(AMD) tend to increase. The research results provide some design parameters for the twin-fluid nozzle, and the experimental results could serve as a beneficial suppleme

关键词： Atomizing nozzle Twin-fluid Sauter mean diameter Arithmetic mean diameter Self-excited vibrating cavity Phase Doppler particle analyzer

Macro-and Microstructure Evolution of 5CrNiMo Steel Ingots during Electroslag Remelting Process

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Journal of Iron and Steel Research International 2014年第7期21卷 644-652页

作者： Lei RAO jian-hua zhao Zhan-xi zhao Gang DING Mao-peng GENG College of Mechanical and Electronic Engineering Hohai University Xinya Special Steel Forging Co. Ltd. College of Mechanical and Electronic Engineering Nanchang University

A comprehensive mathematical model was established and used to simulate the macro and microstructure evolution during the production process of 5CrNiMo steel ingot by electroslag remelting （ESR） method. Along the ingot height, the macrostructure distribution characteristics changed from vertical, fine columnar grains to tilted, coarse columnar grains, and this transformation process occurred at the very beginning of ESR. In the cross section of the ingot, there were three grain morphology regions and two grain type transition regions from the outside to the center of the ingot. These regions were the fine columnar grain region, columnar competitive growth transition re gion, coarse columnar grain region, columnar to equiaxed grain transition （CET） region, and coarse equiaxed grain region. The influence of the remelting rate on the macrostructure and mlcrostructure was investigated using a series of experiments and simulations. The results showed that a low remelting rate could produce a small grain growth angle （GGA） ; the average secondary dendrite arm spacing （SDAS） firstly decreased and then increased as the remelting rate increased. An excessively high or low remelting rate can increase the GGA and average SDAS in ingots. Thus, the remelting rate should be controlled within a suitable range to reduce composition microsegregation and microshrinkage in the ingot to produce an ESR ingot with satisfactory hot forging performance.

关键词： electroslag remelting macrostructure microstructure remelting rate secondary dendrite arm spacing

The Freezing Precipitation over the Middle-Lower Reaches of the Yangtze River during February-March 2009

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Atmospheric and Oceanic Science Letters 2009年第3期2卷 177-182页

作者： SUN jian-hua zhao Si-Xiong Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

In this paper, the authors analyze the quasistationary fronts, surface conditions, and atmospheric stratification processes associated with a freezing precipitation event over the middle-lower reaches of the Yangtze River, especially in the Dabie mountain during February-March 2009. The long duration of freezing precipitation was primarily caused by stationary and anomalous synoptic weather patterns, such as a blocking high pressure in the northern branch and a trough in the southern branch of the westerlies, which resulted in the encounter cold air from northern China and warm moisture from the south. The east-west-oriented, quasi-stationary front （or shear line） found in central China was mostly responsible for producing the precipitation. The warm layer and nearsurface frozen layer were located in the lower troposphere along the front zone. Although the warm layer （〉 0℃） existed along the whole front, a surface temperature less than 0℃ appeared only over the lower-middle reaches of the Yangtze River, especially in the Dabie mountain. Therefore, the surface temperature was the main influencing factor, as the freezing precipitation only happened over the Dabie mountain.

关键词： freezing precipitation quasi-stationary front stratification warm layer

Effect of HEA/Al composite interlayer on microstructure and mechanical property of Ti/Mg bimetal composite by solid-liquid compound casting

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China Foundry 2023年第1期20卷 1-11页

作者： Jin Cheng jian-hua zhao Chun Wang Jing-jing Shangguan Cheng Gu Ya-jun Wang College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China Beijing Power Machinery Research Institute Beijing 100074China

In this study,HEA/AI composite interlayer was used to fabricate Ti/Mg bimetal composites by solidliquid compound casting *** Al layer was prepared on the surface of TC4 alloy by hot dipping,and the FeCoNiCr HEA layer was prepared by magnetron sputtering onto the Al *** influence of the HEA layer thickness and pouring temperature on interface evolution was investigated based on SEM observation and thermodynamic *** indicate that the sluggish diffusion effect of HEA can effectively inhibit the interfacial diffusion between Al and Mg,which is conducive to the formation of solid solution,especially when the thickness of HEA is 800 *** the increase of casting temperature from 720 ℃ to 730 ℃,740℃,and 750 ℃,α-Al(Mg),α-Al(Mg)+Al3Mg2,Al3Mg2+Al12Mg17,and Al12Mg17+δ-Mg are formed at the interface of Ti/Mg bimetal,*** the thickness of the HEA layer is 800 nm and the pouring temperature is 720 ℃,the bonding strength of the Ti/Mg bimetal can reach the maximum of 93.6 MPa.

关键词： Ti/Mg bimetal composite microstructure solid-liquid compound casting HEA/Al composite interlayer mechanical property

Abrasive Wear Resistance of Dual Phase Steels DP980 and DP600

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Journal of Iron and Steel Research International 2015年第4期22卷 317-323页

作者： Xiu-lin JI Ju-yi WANG Cui-cui JI jian-hua zhao Engineering Research Center of Dredging Technology of Ministry of Education Hohai University College of Mechanical and Electrical Engineering Hohai University

The abrasive wear resistance of dual phase （DP） steels DP980 and DP600 was investigated by using an ASTM rubber wheel abrasion tester. At 2.40 m ·s-1 sliding speed under 19.9 N load with 180--355μm abrasive sands, the wear rates of DP980 and DP600 were 1.01 × 10^-11 and 0.86 ×10^-11 m3 · m-1 , respectively, correspond- ing to about 1.9 and 2.3 times of the relative wear resistance of normal low-carbon steel ASTM A283C. Using di- rectly water quenching from austenitic temperature, the abrasive wear resistance of DP980 samples under 19.9 N load could be improved by 1.65 times. The wear rates of DP980 and DP600 samples decreased respectively with in- creasing sliding speed and abrasive particle size and decreasing applied load. The experimental results reveal that the effect of martensite on the wear resistance not only depends on the volume fraction but also depends on the morphol- ogy, distribution and grain size.

关键词： abrasive wear annealing wear mechanism DP980 steel

Expression of pathogenesis-related genes in cotton roots in response to Verticillium dahliae PAMP molecules

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Science China(Life Sciences) 2017年第8期60卷 852-860页

作者： Xuan Du Sheng Wang Feng Gao Lisha Zhang jian-hua zhao Hui-Shan Guo Chenlei hua State Key Laboratory of Plant Genomics Institute of MicrobiologyChinese Academy of Sciences College of Life Sciences University of the Chinese Academy of Sciences College of Agriculture Shihezi University and Key Laboratory at Universities of Xinjiang Uygur Autonomous Region for Oasis Agricultural Pest Management and Plant Protection Resource Utilization

Verticillium wilt disease becomes a major threat to many economically important crops. It is unclear whether and how plant immunity takes place during cotton-Verticillium interaction due to the lack of marker genes. Taking advantage of cotton （Gossypium hirsutum） genome, we discovered pathogenesis-related （PR） gene families, which have been widely used as markers of immune responses in plants. To profile the expression of G. hirsutum PR genes in the process of plant immunity, we treated cotton roots with two immunogenic peptides, fig22 and nlp20 known as pathogen-associated molecular patterns, as well as three Verticillium dahliae-derived peptides, nlp20vd2, nlp23vd3, and nlp23vd4 which are highly identical to nlp20. Quantitative real-time PCR results revealed that 14 G. hirsutum PR gene （GhPR） families were induced or suppressed independently in response to fig22, nip20, nlp20va2, nlp23vd3, and nlp23vd4. Most GhPR genes are expressed highest at 3 h post incubation of immunogenic peptides. Compared to fig22 and nlp20, nlp20vd2 is more effective to trigger up-regulated expression of GhPR genes. Notably, both nlp23vd3 and nlp23vd4 are able to induce GhPR gene up-regulation, although they do not induce necrosis on cotton leaves. Thus, our results provide marker genes and new immunogenic peptides for further investigation of cotton-V, dahliae interaction.

关键词： Verticillium wilt Gossypium hirsutum PR gene PAMP nip20

The RNA-binding domain of DCL3 is required for long-distance RNAi signaling

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aBIOTECH 2024年第1期5卷 17-28页

作者： Jie Li Bo-Sen Zhang hua-Wei Wu Cheng-Lan Liu Hui-Shan Guo jian-hua zhao State Key Laboratory of Plant Genomics Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Biotic Interactions University of the Chinese Academy of SciencesBeijing 100049China Qilu Zhongke Academy of Modern Microbiology Technology Jinan 250022China

Small RNA(sRNA)-mediated RNA silencing(also known as RNA interference,or RNAi)is a conserved mechanism in eukaryotes that includes RNA degradation,DNA methylation,heterochromatin formation and protein translation *** plants,sRNAs can move either cell-to-cell or systemically,thereby acting as mobile silencing signals to trigger noncell autonomous ***,whether and what proteins are also involved in noncell autonomous silencing have not been *** this study,we utilized a previously reported inducible RNAi plant,PDSi,which can induce systemic silencing of the endogenous PDS gene,and we demonstrated that DCL3 is involved in systemic PDS silencing through its RNA binding *** confirmed that the C-terminus of DCL3,including the predicted RNA-binding domain,is capable of binding short *** affecting RNA binding,but not processing activity,reduced systemic PDS silencing,indicating that DCL3 binding to RNAs is required for the induction of systemic *** mosaic virus infection assays showed that the RNA-binding activity of DCL3 is required for antiviral RNAi in systemically noninoculated *** findings demonstrate that DCL3 acts as a signaling agent involved in noncell autonomous silencing and an antiviral effect in addition to its previously known function in the generation of 24-nucleotide sRNAs.

关键词： RNAi signaling DCL3 RBD RNAs Cucumber mosaic virus