Insight into Function and Subcellular Localization of a Type III-Secreted Effector in Pseudomonas syringae pv. tomato DC3000

Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) is a bacterial pathogen of tomato and of the model plants Arabidopsis and Nicotiana benthamiana (N. benthamiana). Like numerous Gram-negative bacterial pathogens of animals and plants, Pst DC3000 exploits the conserved type III secretion system (TTSS) to deliver multiple virulence effectors directly into the host cells. Type III effectors (T3Es) collectively participate in causing disease, by mechanisms that are not well clarity. Elucidating the virulence function of individual effector is fundamental for understanding bacterial infection of plants. Here, we focused on studying one of these effectors, HopAA1-1, and analyzed its potential function and subcellular localization in N. benthamiana. Using an Agrobacterium-mediated transient expression system, we found that HopAA1-1 can trigger domain-dependent cell death in N. benthamiana. The observation using confocal microscopy showed that the YFP-tagged HopAA1-1 localizes to diverse cellular components containing nucleus, cytoplasm and cell membrane, which was demonstrated through immunoblot analysis of membrane fractionation and nuclear separation. Enforced HopAA1-1 subcellular localization, by tagging with a nuclear localization sequence (NLS) or a nuclear export sequence (NES), shows that HopAA1-1-induced cell death in N. benthamiana is suppressed in the nucleus but enhanced in the cytoplasm. Our research is lay a foundation for revealed the molecular pathogenesis of Pseudomonas syringae pv. tomato.

Structural and Functional Insights into an Arabidopsis NBS-LRR Receptor in Nicotiana benthamiana

Nucleotide-binding site leucine-rich repeat receptors (NBS-LRR/NLRs) are crucial intracellular immune proteins in plants. Previous article reported a novel NLR protein SUT1 (SUPPRESSORS OF TOPP4-1, 1), which is involved in autoimmunity initiated by type one protein phosphatase 4 mutation (topp4-1) in Arabidopsis, however, its role in planta is still unclear. This study employed Nicotiana benthamiana, a model platform, to conduct an overall structural and functional analysis of SUT1 protein. The transient expression results revealed that SUT1 is a typical CNL (CC-NBS-LRR) receptor, both fluorescence data and biochemical results showed the protein is mainly anchored on the plasma membrane due to its N-terminal acylation site. Further truncation experiments announced that its CC (coiled-coil) domain possessed cell-death-inducing activity. The outcomes of point mutations analysis revealed that not only the CC domain, but also the full-length SUT1 protein, whose function and subcellular localization are influenced by highly conserved hydrophobic residues. These research outcomes provided favorable clues for elucidating the activation mechanism of SUT1.

The Application of Nicotiana benthamiana as a Transient Expression Host to Clone the Coding Sequences of Plant Genes

Coding sequences (CDS) are commonly used for transient gene expression, in yeast two-hybrid screening, to verify protein interactions and in prokaryotic gene expression studies. CDS are most commonly obtained using complementary DNA (cDNA) derived from messenger RNA (mRNA) extracted from plant tissues and generated by reverse transcription. However, some CDS are difficult to acquire through this process as they are expressed at extremely low levels or have specific spatial and/or temporal expression patterns in vivo. These challenges require the development of alternative CDS cloning technologies. In this study, we found that the genomic intron-containing gene coding sequences (gDNA) from Arabidopsis thaliana, Oryza sativa, Brassica napus, and Glycine max can be correctly transcribed and spliced into mRNA in Nicotiana benthamiana. In contrast, gDNAs from Triticum aestivum and Sorghum bicolor did not function correctly. In transient expression experiments, the target DNA sequence is driven by a constitutive promoter. Theoretically, a sufficient amount of mRNA can be extracted from the N. benthamiana leaves, making it conducive to the cloning of CDS target genes. Our data demonstrate that N. benthamiana can be used as an effective host for the cloning CDS of plant genes.

Expression Pattern, Interaction Network, and Functional Analysis of the Arabidopsis Botrytis Susceptible1 Interactor

E3 ubiquitin ligases are participated in numerous processes, regulating the response to biotic and abiotic stresses. Botrytis susceptible1 interactor (BOI) is a RING (Really Interesting New Gene)-type E3 ligase that mediates the ubiquitination of BOS1 (Botrytis susceptible1), a transcription factor involved in stress and pathogen responses. Although BOI is an E3 ligase, there are reports to show that BOI interacts with target proteins such as DELLAs or CONSTANS to repress gibberellin responses and flowering without the degradation of the target proteins. In this article, we utilize diversified methods to comprehensively analyze the expression pattern, interaction network and function of BOI gene. Firstly, 1800 bp upstream region of BOI gene from Arabidopsis thaliana (Arabidopsis) genome was isolated, and fused GUS reporter gene. The resulting expression cassette was introduced into wild-type Arabidopsis through Agrobacterium-mediated transformation. The result demonstrated that BOI gene was expressed predominantly in leaves, siliques, young roots, and flowering tissues, indicating that BOI gene may be involved in multiple processes in plant growth and development in Arabidopsis. Besides, eight candidate interacting proteins were obtained from the Arabidopsis cDNA library via yeast two-hybrid technology, including EXO70E2 (AT5G61010), WRKY7 (AT4G24240), WRKY11 (AT4G31550), WRKY17 (AT2G24570), UBP20 (AT4G17895), L5 (AT1G12290), SAUR9 (AT4G36110) and TCP21 (AT5G08330). Functional analysis of these candidate interacting proteins manifested that they related to multiple pathways, including biological and abiotic stress, programmed cell death, protein degradation, material metabolism and transcriptional regulation. In addition, the results of the transient assay proclaimed that BOI protein affects the protein stability of EXO70E2 and L5 through its E3 ubiquitin ligase activity. Our results provide novel clues for a better understanding of molecular mechanisms underlying BOI-mediated regulations.

Screening and Identifying of Interaction Protein AtL5 in Arabidopsis thaliana

Research background: The Arabidopsis-resistance protein L5 (AT1G12290) can trigger cell death in Nicotiana benthamiana, which is a characteristic function of an NBS-LRR (Nucleotide-Binding Sites and Leucine-Rich Repeat) protein activation. Purpose: To explore the function and molecular regulatory network of L5. Method: We employed yeast two-hybrid technology to search for interacting proteins of L5, combined with laser confocal microscopy to observe the subcellular localization of these candidate proteins, and analyzed the impact of these proteins on L5 function using an Agrobacterium mediated transient expression system. Results: Seven candidate interacting proteins were identified from the Arabidopsis cDNA library, including PPA1 (AT1G01050), RIN4 (AT3G25070), LSU1 (AT3G49580), BZIP24 (AT3G51960), BOI (AT4G19700), RING/U (AT4G22250) and PPA3 (AT2G46860). Functional analysis of these candidate interacting proteins showed that they participated in multiple pathways, including biological and abiotic stress, programmed cell death, protein degradation, material metabolism and transcriptional regulation. The results of laser confocal microscopy manifested that RIN4 was only localized on the plasma membrane (PM), and RING/U was mainly associated with the PM. PPA1, PPA3, LSU1, BZIP24, and BOI all emerged nuclear and cytoplasmic localization. The results of the transient assay proclaimed that both BOI and RING/U can inhibit cell death caused by L5. Conclusions: These results indicate that L5 immune receptors may participate in various pathways, and their protein levels and activities are strictly regulated at multiple levels, providing a basis for elucidating the mechanism of L5 immune receptors in Arabidopsis resistance.

Dissecting Multiple Arabidopsis CC-NBS-LRR Proteins Structure and Localization

NBS-LRR (nucleotide binding sites and leucine rich repeat) protein plays a crucial role as sentries and as defense activators in plants. The structure and function of NBS-LRR proteins are closely related. Previous articles have announced that the activated ZAR1 (HopZ-Activated Resistance 1) forms a pentamer in the plasma membrane, which is a calcium permeable channel that can trigger plant immune signaling and cell death. However, the structure of galore NBS-LRRs in Arabidopsis is not yet clear. The functional sites of distinct NBS-LRR in cells may vary. In addition, identifying pathogens and activating defense regions may occur in different subcellular compartments. Therefore, dissecting the specific structure and positioning of NBS-LRRs is an indispensable step in understanding their functions. In this article, we exploit AlphaFold to predict the structure of some designed NBS-LRRs, and utilize Agroinfiltration transient expression system, combined with biochemical fractionation, to dissect the localization of these NBS-LRR receptors from Arabidopsis. Structural data indicates that the identified NBS-LRRs share analogous conformation. Membrane fractionation assay demonstrates these NBS-LRRs are mainly associated with the membrane. These data show that the Ca2+-permeable channel activity may be evolutionarily conserved in NBS-LRR of Arabidopsis, and this study provides some reference clues for analyzing the structure and localization patterns of other plant immune receptors.

超短c轴盘簇L沸石介晶的晶种诱导合成:形貌控制、解耦机理和增强吸附

缩短沸石材料的微孔孔道能有效提升客体分子的扩散传质性能。但目前一维L沸石(LTL)的合成中,缩短其沿一维微孔孔道方向(c轴方向)的长度至20到50 nm仍是一个挑战。本文首次在简单无机体系中通过加入纳米棒簇状L沸石作为晶种,快速(仅需4 h)合成了一种新型的L沸石介观结构晶体,且无需外加任何晶化修饰剂与模板剂。该介晶呈现出一种由超薄(约29 nm)的圆盘纳米晶沿c轴定向堆叠而成的盘簇形貌。这一独特的晶种诱导策略能够有效解耦L沸石的成核和生长阶段,为精确调控每个阶段的晶化行为以获得所需形貌结构提供了更大的操作空间。通过分析合成体系中介观尺度的晶核和微观尺度的基本构建单元衍化规律,实现了对晶种具体作用及衍化规律的解构:晶种溶解出的环笼结构加速了凝胶有序化,缩短了诱导期;而晶种溶解后的残余部分为生长期提供了密集的初始晶核,导向了新型盘簇结构的形成。通过对沸石生长条件进行调节,证实了其生长期存在蠕虫状前驱颗粒组装的行为,并实现了对盘簇中圆盘沿c轴方向厚度在18到55 nm范围内的精细调控。此外,通过选择直径为0.43到4.5 nm的系列模型分子作为吸附质,证明了该超短c轴样品在气相和液相体系大幅增强的吸附应用潜力。样品在小分子的扩散速率和大分子在气相的吸附量方面确实具有优势。在实际应用中,该样品在芳烃的吸附和分离以及染料和蛋白质的吸附方面具有一定的优势。

In Silico Screening of Potential Inhibitors against dPLA2 from Named Chinese Herbs for Identification of Compounds with Antivenom Effects Due to Deinagkistrodon acutus Snake Bites

Phospholipase A2 (PLA2) is the key enzyme to the venom from Deinagkistrodon acutus which is one of the highly venomous snakes in China. In addition to being a catalyst for the hydrolysis of phospholipases A2 from snake venom, its well known that it possesses a broad spectrum of pharmacological activities, such as myotoxicity, neurotoxicity, cardiotoxicity, and hemolytic, anticoagulant and antiplatelet activities. However, snakebites are not efficiently treated by conventional serum therapy. Acute wounds can still cause poisoning and death. In order to find effective inhibitors of Deinagkistrodon venom acid phospholipase A2 (dPLA2), we obtained 385 compounds in 9 Chinese herbs from the TCMSP. These compounds were further performed to virtual screen using in silico tools like ADMET analysis, molecular docking and molecular dynamics (MD) simulation. After Pharmacokinetics analysis, we found 7 candidate compounds. Besides, analysis of small molecule interactions with dPLA2 confirmed that the amino acid residues HIS47 and GLY29 are key targets. Because they bind not only to the natural substrate phosphatidylcholine and compounds known for having inhibitory functions, but also for combining with potential antidote molecules in Chinese herbal medicine. This study is the first to report experience with virtual screening for possible inhibitor of dPLA2, such as the interaction spatial structure, binding energy and binding interaction analysis, these experiences not only provide reference for further experimental research, but also have a guideline for the study of drug molecular mechanism of action.

铜乙二胺法测定中国手工纸纤维素特性粘度的改进实验

介绍了一个通过铜乙二胺法测定纤维素特性粘度的改进实验。在该方法中,木质素对纤维素特性粘度的测定会产生巨大影响。为了探讨这一问题,本实验构建纤维素-木质素模型,讨论了木质素含量对纤维素特性粘度的影响,并采用改进的计算方法获得了更加准确的纤维素特性粘度和聚合度。此外,还探讨了与空气接触时,不同溶解时间对纤维素铜乙二胺特性粘度的影响。该实验是纤维素相关材料的基本表征实验,学生可以了解纤维素的基本性质和溶解机理,以及高分子材料粘度的测定和粘度计的使用方法,还可以学习构建简单模型对各组分影响进行探讨。

Network Security Situation Awareness Framework based on Threat Intelligence

Network security situation awareness is an important foundation for network security management,which presents the target system security status by analyzing existing or potential cyber threats in the target system.In network offense and defense,the network security state of the target system will be affected by both offensive and defensive strategies.According to this feature,this paper proposes a network security situation awareness method using stochastic game in cloud computing environment,uses the utility of both sides of the game to quantify the network security situation value.This method analyzes the nodes based on the network security state of the target virtual machine and uses the virtual machine introspection mechanism to obtain the impact of network attacks on the target virtual machine,then dynamically evaluates the network security situation of the cloud environment based on the game process of both attack and defense.In attack prediction,cyber threat intelligence is used as an important basis for potential threat analysis.Cyber threat intelligence that is applicable to the current security state is screened through the system hierarchy fuzzy optimization method,and the potential threat of the target system is analyzed using the cyber threat intelligence obtained through screening.If there is no applicable cyber threat intelligence,using the Nash equilibrium to make predictions for the attack behavior.The experimental results show that the network security situation awareness method proposed in this paper can accurately reflect the changes in the network security situation and make predictions on the attack behavior.

First-principles investigation of the significant anisotropy and ultrahigh thermoelectric efficiency of a novel two-dimensional Ga_(2)I_(2)S_(2) at room temperature

Two-dimensional(2D)thermoelectric(TE)materials have been widely developed;however,some 2D materials exhibit isotropic phonon,electron transport properties,and poor TE performance,which limit their application scope.Thus,exploring excellent anisotropic and ultrahigh-performance TE materials are very warranted.Herein,we first investigate the phonon thermal and TE properties of a novel 2D-connectivity ternary compound named Ga2I2S2.This paper comprehensively studies the phonon dispersion,phonon anharmonicity,lattice thermal conductivity,electronic structure,carrier mobility,Seebeck coefficient,electrical conductivity,and the dimensionless figure of merit(ZT)versus carrier concentration for 2D Ga_(2)I_(2)S_(2).We conclude that the in-plane lattice thermal conductivities of Ga_(2)I_(2)S_(2) at room temperature(300 K)are found to be 1.55 W mK^(−1) in the X-axis direction(xx-direction)and 3.82 W mK^(−1)in the Y-axis direction(yy-direction),which means its anisotropy ratio reaches 1.46.Simultaneously,the TE performance of p-type and n-type doping 2D Ga2I2S2 also shows significant anisotropy,giving rise to the ZT peak values of p-type doping in xx-and yy-directions being 0.81 and 1.99,respectively,and those of n-type doping reach ultrahigh values of 7.12 and 2.89 at 300 K,which are obviously higher than the reported values for p-type and n-type doping ternary compound Sn2BiX(ZT∼1.70 and∼2.45 at 300 K)(2020 Nano Energy 67104283).This work demonstrates that 2D Ga_(2)I_(2)S_(2) has high anisotropic TE conversion efficiency and can also be used as a new potential room-temperature TE material.

High-performance self-powered photodetector based on organic/inorganic hybrid van der Waals heterojunction of rubrene/silicon

Organic/inorganic hybrid van der Waals heterostructure with an atomically abrupt interface has attracted great research interests within the field of multifunctional electronic and optoelectronic devices.The integration of organic rubrene films with inorganic Si semiconductors can avoid the atomic mutual-diffusion at the interface,and provide the possibility of forming two-dimensional van der Waals heterojunction accompanied with the type-II energy band alignment,due to the transfer behaviors of majority carriers at the interface.In this study,the high-quality rubrene/Si van der Waals heterostructure with an electronically abrupt junction was prepared,and a self-powered photodetector was then constructed based on this hybrid heterojunction.The photodetector demonstrated an excellent switching response to the 1064 nm monochromatic light with large on/off current ratio of 7.0×10^(3),the maximum photocurrent of 14.62 m A,the maximum responsivity of 2.07 A/W,the maximum detectivity of 2.9×10^(11)Jones,and a fast response time of 13.0μs.This study offers important guidance for preparing high-quality rubrene/Si hybrid van der Waals heterostructure with desirable band alignment,and the designed heterojunction photodetector has an important application prospect in the field of multifunctional optoelectronics.

Total Synthesis of Dimeric HPI Alkaloids

In this paper,we report a full account of the synthesis of dimeric hexahydropyrroloindole alkaloids and its analogues.The key feature of our new strategy is the novel catalytic copper(10%)mediated intramolecular arylations of o-haloanilides followed by intermolecular oxidative dimerization of the resulting oxindoles in one pot.This sequential reaction leads to the key intermediates for the synthesis of(+)-chimonanthine,(+)-folicanthine,(-)-calycanthine and(-)-ditryptophenaline.Graphical Abstract In the presence of catalytic amount of cuprous iodide(10%),an intramolecular arylation of ohaloanilides followed by an intermolecular oxidative dimerization of the resulting oxindoles leads to a commonintermediate for the synthesis of(+)-chimonanthine,(+)-folicanthine and(-)-calycanthine.Based on this cascade sequence,we also developed a flexible strategy towards the asymmetric syntheses of dimeric HPI alkaloids(-)-ditryptophenaline and its analogues.

Applied study of sentinel lymph node biopsy in colorectal cancer

Objective： The aim of this study was to investigate the feasibility of sentinel lymph node biopsy （SLNB） in colorectal cancer. Methods： Twenty patients of colorectal cancer were enrolled in this study. Endoscopic injection submucosally of ^99m Tc-DX was performed around the primary tumor 3 h before operation. Immediately after laparotomy, methylene blue was injected into subserosal layer adjacent to the tumor. Sentinel lymph nodes （SLNs） were defined as blue stained nodes or （and） those containing 10 times more radioactivity than surrounding tissue with a y probe, all resected nodes were examined postoperatively by routine rapid frozen examination and HE stain. The diagnostic nodes metastasis states and false-negative rate of regional lymph node status on the basis of SLNs were calculated respectively. Results： SLNs were detected in 16 of 20 patients with a successful detection rate of 80%, the number of SLNs ranged from 1 to 3, with a mean value of 2.4 per case, metastasis rate of SLNs were 37.5% （18/48）, the diagnostic sensitivity was 80% （16/20）, the diagnostic accuracy was 83.3% （15/18）, the false-negative rate was 20% （4/20）. Conclusion： The SLN concept is validated in colorectal cancer. Com- bined-agent SLN mapping is an accurate diagnostic procedure for detecting lymph node metastasis in patients with colorectal cancer and may indicate rational extent of lymphadenectomy for colorectal cancer.

Virtual Screening and Mechanism Analysis of Effective Components from Several Chinese Herbs to Inhibit dPLA2 of Deinagkistrodon acutus Venom

Objective: In folk and TCM clinical medicine, Chinese herbal medicine is used to treat snakebite and has good curative effect, but its active ingredients and mechanism are still unclear. In this study, virtual screening and mechanism analysis of effective components from 6 Chinese herbs to inhibit phospholipase A2 of Deinagkistrodon acutus (dPLA2) venom were conducted. Methods: With advanced computing software AutoDock, Pymol and GROMACS, the molecules selected from the Chinese herbal Medicine Chemical Composition databas6e (TCMSP) were docked with the dPLA2 from the protein database (PDB). Further molecular dynamics simulation was used to evaluate the molecular binding stability. Results: Four potential dPLA2-inhibiting molecules were screened: lobelanidine, lobeline, norlobelanine and pratensein, by analyzing the spatial structure, binding energy and binding interaction of small molecular-dPLA2 complexes, as well as the RMSD and RMSF of molecular dynamics simulation. Conclusion: To our knowledge, this is the first report of lobeline has an inhibitory effect on dPLA2, and lobelanidine, as a precursor of lobeline, has a stronger inhibitory effect. According to the docking results, it is speculated that the mechanism of action of the four molecules is to form stable interactions with calcium ions and amino acid residues on the calcium ion binding ring in dPLA2. Moreover, these small molecules compete with phosphatidylcholine (the natural substrate of dPLA2) to bind dPLA2 and have a higher affinity than phosphatidylcholine, resulting in inhibition of dPLA2 activity.

水力旋流器并联公共液斗对压降的影响研究

为降低并联水力旋流器组压降,设计了一种并联水力旋流器公共液斗。实验测量了常规并联旋流器组和带液斗的并联旋流器组的压降,并利用Fluent软件分析了并联分离器的流场。结果表明,带液斗的并联旋流器组的压降均低于常规组,平均减少了1.9%,当入口流速增大至5.0 m/s后,压降减小幅度最大达3.36%。带液斗的并联旋流器组的分离效率均高于常规组,平均增加了0.94个百分点,当入口流速增大至5.0 m/s后,分离效率增加幅度最大达1.34个百分点。与常规并联相比,带液斗的并联旋流器组内空气柱消失,导致湍动能耗散减小且切向速度变化更为平缓。液斗内并行涡流会受到其他旋涡约束,旋涡系中心比单个旋涡中心摆动幅度要小,稳定性更强。公共液斗能够有效降低并联旋流器分离压降,本工作可为并联水力旋流器的设计和应用提供指导。

农田节肢动物不同取样方法的综合比较

农田节肢动物多样性具有病虫害控制、传粉等价值,选择一种或多种适宜、准确且高效的取样方法和指示类群来衡量农田节肢动物多样性是一项基础性工作。本文通过地表陷阱法、挂盆陷阱法、扫网法、目测计数法和吸虫器法在有机管理和常规管理农田区的不同农业生境类型中取样,比较不同方法对不同生物类群的捕获效率、经济成本、响应敏感性等。研究发现在捕获效率方面,地陷法和挂盆法最高,其次是扫网法,而吸虫器法和目测计数法较差。挂盆法对步甲、蜘蛛、蜂类和瓢虫类群的捕获效率较佳。陷阱法主要适用于蜘蛛和步甲的取样,扫网法也可用于蜘蛛和瓢虫的取样。在经济成本方面,地陷法的成本最低,扫网法的总成本最高。每种取样方法下仅有个别类群个体数量具有较好的响应敏感性,如地陷法的蜘蛛目个体数和步甲科个体数、挂盆法的总个体数、蜂类个体数和瓢虫科个体数、扫网法的直翅目个体数和半翅目个体数等。在此基础上,综合类群经济价值,操作难易,类群鉴定难度,被动取样程度,是否受取样人影响等比较发现:地陷法对步甲和蜘蛛的取样的综合效果最佳,而不同取样方法下多种类群的组合能更好地监测和评价农田节肢动物多样性的整体情况。地陷法捕获步甲或/和蜘蛛以及挂盆法调查蜂类的组合是基于本研究得出的调查农田节肢动物多样性的最佳组合。

超声对晚发型胎儿生长受限不良围产期结局的预测价值

目的探讨超声对晚发型胎儿生长受限(FGR)不良围产期结局的预测因素,并分析其诊断效能。方法回顾性分析2015年12月至2021年5月郑州大学第三附属医院收治的149例产前诊断为晚发型FGR患者的超声声像图及临床资料,按照是否出现不良围产期结局分为不良围产期结局组(72例)和对照组(77例)。记录一般临床资料及分娩前1周内经超声测量的大脑中动脉搏动指数(MCA-PI)、脐动脉搏动指数(UA-PI)、脑胎盘比(CPR)、羊水-脐脑比(AUCR)及估计胎儿体质量(EFW)。采用两独立样本t检验、Mann-WhitneyU检验、χ^(2)检验比较组间上述指标的差异,采用单因素和多因素Logistic逐步回归分析确定晚发型FGR不良围产期结局的预测因素,构建受试者操作特征(ROC)曲线分析各超声参数对不良围产期结局的预测效能。结果与对照组相比,不良围产期结局组AUCR、EFW百分位数、CPR、MCA-PI、最大羊水暗区垂直深度均明显降低[30.63±10.33vs39.70±11.15;3.2(2.1,6.4)vs5.7(3.5,8.9);1.18±0.28vs1.37±0.21;1.22±0.26vs1.34±0.23;27.50(22.00,31.00)mmvs29.00(23.50,34.50)mm],UA-PI明显增高(1.05±0.20vs0.98±0.16),差异具有统计学意义(t=5.138,P<0.001;Z=-4.618,P<0.001;t=4.464,P<0.001;t=3.129,P=0.002;Z=-2.292,P=0.022;t=-2.504,P=0.013)。多因素Logistic逐步回归分析显示AUCR、EFW百分位数、CPR为晚发型FGR不良围产期结局的独立预测因素(OR=0.951、0.753、0.154,P=0.024、<0.001、=0.044)。经过ROC曲线分析,AUCR、EFW百分位数、CPR预测晚发型FGR不良围产期结局的界值、敏感度、特异度分别为39.64、53.2%、81.9%;4.85、66.2%、66.7%;1.19、81.8%、51.4%。AUCR、EFW百分位数、CPR 3个变量联合的多参数模型对不良围产期结局的诊断效能提升,弥补了单项参数预测晚发型FGR不良围产期结局敏感度与特异度失衡的问题,ROC曲线下面积为0.795,敏感度、特异度分别为76.6%、70.8%。结论超声检查在预测晚发型FGR不良围产期结局中具有重要价值,AUCR、EFW百分位数及CPR是晚发型FGR不良围产期结局的独立预测因素,可为产前咨询和临床处理提供依据。

沸石的连续流动相合成

由于沸石分子筛在多个领域被广泛应用,高效可靠的沸石合成方法早已成为人们研究的重点。相较于传统高压釜水热间歇合成方法,沸石的连续流动相合成方法晶化时间短,时空产率高,是近年来发展的沸石合成新路线。利用连续流动反应器(CFR)的热延迟效应低、传质效果好和方法拓展性强等特点,可以在分钟级乃至秒级时间内实现高结晶度沸石合成,大大提升了合成效率和可控度。基于近期该领域的进展,本文介绍了沸石的连续流动反应器结构,其合成过程优势和产物特点及受限之处,并对其未来应用加以展望。

Seed-induced synthesis of functional MFI zeolite materials:Method development,crystallization mechanisms,and catalytic properties

As an important zeolite material,MFI zeolites,as well as their controllable synthesis,are of great interest in both basic and applied science.Among the developed synthetic approaches,the seed-induced method has gradually evolved into a facile,low-cost,and even green alternative to give zeolites the desirable physicochemical properties.In this review,we briefly summarize the development of seed-induced syntheses of diverse functional MFI zeolites,where the“living”seed crystals not only direct the formation of zeolitic framework but also function as special“templates”or“units”to fine-tune the zeolite materials with diverse sizes,shapes,compositions,morphologies and pore structures.Moreover,on the basis of their structural features and crystallization behaviors in seed-induced synthesis,we reveal the roles of seeds and discuss the related crystallization mechanisms including both classical and non-classical pathways.We also want to guide readers to investigate the structure-performance relationships between these functional MFI zeolite catalysts and suitable catalytic reactions.