MdATG18a overexpression improves basal thermotolerance in transgenic apple by decreasing damage to chloroplasts

High temperature is an abiotic stress factor that threatens plant growth and development.Autophagy in response to heat stress involves the selective removal of heat-induced protein complexes.Previously,we showed that a crucial autophagy protein from apple,MdATG18a,has a positive effect on drought tolerance.In the present study,we treated transgenic apple(Malus domestica)plants overexpressing MdATG18a with high temperature and found that autophagy protected them from heat stress.Overexpression of MdATG18a in apple enhanced antioxidase activity and contributed to the production of increased beneficial antioxidants under heat stress.Transgenic apple plants exhibited higher photosynthetic capacity,as shown by the rate of CO_(2) assimilation,the maximum photochemical efficiency of photosystem II(PSII),the effective quantum yield,and the electron transport rates in photosystems I and II(PSI and PSII,respectively).We also detected elevated autophagic activity and reduced damage to chloroplasts in transgenic plants compared to WT plants.In addition,the transcriptional activities of several HSP genes were increased in transgenic apple plants.In summary,we propose that autophagy plays a critical role in basal thermotolerance in apple,primarily through a combination of enhanced antioxidant activity and reduced chloroplast damage.

Comparison on Chromosome Number among Ussuri Raccoon Dogs with Three Different Coat Colors

[ Objective] This study aimed to lay theoretical foundation for establishing the database of biological characteristics of raccoon dogs with different coat colors. [Method] Reddish-brown ussuri raccoon dogs, wild ussuri raccoon dogs and Jilln white raccoon dogs were used as experimental materials in this study. Chromosome specimens were prepared by peripheral blood lymphocyte culture, to analyze chromosome number of ussuri raccoon dogs with different coat colors. [ Result] Frequencies of cells with diploid chromosome number of 56 in reddish-brown ussuri raccoon dogs and wild ussuri raccoon dogs were 86% and 83% re- spectively, indicating that the chromosome number of reddish-brown ussuri raccoon dogs and wild ussuri raccoon dogs was 56. The frequency of cells with diploid chromosome number of 56 in Jilin white raccoom dogs was 70%, which was lower than that of other two varieties, while the frequency of cells with 2n = 57 was high- er than that of other two varieties. [Conclusion] The chromosome number was 56 for reddish-brown ussuri raccoon dogs and wild ussuri raccoon dogs, and it was 56 or 57 for Jllin white raccoon dogs, which represented pelymorphism.

Synchronous shield tunnelling technology combining advancement and segment fabrication:Principle,verification and application

Through the active control of shield thrust system oil pressures,a synchronous shield tunnelling technology combining advancement and segment fabrication was proposed.The key to this technology was to completely exploit the additional stroke of the hydraulic jacks generated by the axial insertion of a key block to assemble the segments.Taking the tunnelling project of the Shanghai Airport Railway Link Line as a demonstration project,this paper uses a large model test platform for this synchronous technology.A single-ring construction process along a straight line was simulated,in which the theoretical external loads were implemented on the shield machine.The feasibility and reliability of this synchronous technology were evaluated considering the accuracy of total thrust force control,maintenance of tunnelling speed and shield postures and segment compression.The effectiveness of the redistribution principle for the missing thrust force due to the withdrawal of cylinders located in the segment fabrication region was discussed.Furthermore,some other interesting phenomena were observed in the practical application in addition to the model test.This technology primarily realizes synchronous assembly by improving the control of the propulsion system of conventional shield machines without any transformation of the shield machine’s primary structure,segment patterns or excavation method.The proposed method has good adaptability and a low construction cost,which will be beneficial for future long-distance tunnelling projects.

继承与创新:由共同体走向学习共同体

学习共同体曾被描述为21世纪学校的愿景之一。本研究基于学习共同体发展概况,从概念溯源、内涵界定、发展趋势与特征等多角度进一步探究,得到的结论如下:第一,当代学习共同体的概念是建立在对滕尼斯、韦伯、吉登斯、鲍曼等学者共同体思想的继承和对杜威、彼得·圣吉、萨乔万尼、博耶等学者学习共同体理解的创新之上;第二,学习共同体是包涵认知、情感、行为、意志四大层面内容的学习生态系统,共同目标、共同意识或共同理解是学习共同体生成的首要前提,归属感、身份认同和意义感知是学习共同体生成的情感纽带,对话、协商、合作、参与是学习共同体生成的基本保障,参与者的主动性、自发性、反思性是学习共同体产生的根本动力;第三,学习型社会的构建和完善、信息技术的迅猛发展、学习理论的深入研究推进了当代学习共同体的进一步发展,衍生出了'无处不在''和而不同''导向卓越'等新特征。

成人学习者的类型与学习成效:基于学习动机和学习障碍的探究

学习动机和学习障碍被当作透视成人学习者学习成效的两大有力因素。本研究基于类型学研究方法,通过向J大学749位成人学习者发放问卷、依据他们学习动机和学习障碍的行为表现,使用聚类分析、差异检验、判别分析和决策树模型等方法,将成人学习者划分为四种类型:疏离型、理想型、发展型和懒惰型,并进一步检验了其学习成效。研究发现:"弱势"群体——疏离型和懒惰型在成人学习者中占比三成;年龄、以往培训次数、成绩预期是识别不同类型成人学习者的关键个体特征;参与学习的障碍因素对成人学习者学习成效的影响效力高于学习动机;时间障碍并非是影响成人学习成效最重要的障碍因素。研究结论有助于高等继续教育围绕人才培养目标更好地满足成人学习者多元化的学习需求,为成人学习者提供更适合的教育。

Advanced photocatalysts based on metal nanoparticle/metalorganic framework composites

Photocatalysis,via conversion of light into valuable chemicals,is an economic and effective way to utilize inexhaustible solar energy for the sustainable development of our human society.Aiming at killing two birds with one stone,metal nanoparticle(MNP)/metal-organic framework(MOF)composites via integration of the individual advantages of MNP and MOF have been becoming a versatile photocatalyst.Moreover,owing to the synergist effect between each component,MNP/MOF composite photocatalysts usually show greatly promoted catalytic activity,selectivity and long-term recyclability.In this review,first of all,the widely adopted synthesis strategies of MNP/MOF composite are introduced comprehensively,and then their recent advances in photocatalysis including photocatalytic hydrogen production,carbon dioxide reduction,organic transformation reactions and photodegradation of pollutants are summarized and highlighted.Finally,challenges and perspectives among MNP/MOF based photocatalysis are also proposed and discussed for advancing further development in this hot research field.

Structure regulated catalytic performance of gold nanocluster-MOF nanocomposites

Atomically precise gold(Au)nanoclusters(NCs)as visible light photosensitizers supported on the substrate for photoredox catalysis have attracted considerable attentions.However,eficient control of their photocatalytic activity and long-term stability is still challenging.Herein,we report a coordination-assisted self-assembly strategy in combination with electrostatic interaction to sandwich Au2:(Capt)18(abbreviated as AU25,Capt=captopril)NCs between an inner core and an outer shell made of UiO-66,denoted as UiO-66@Au25@UiO-66.Notably,the sandwich-like nanocomposite displays significantly enhanced catalytic activity along with an excellent stability when used in the selective photocatalytic aerobic oxidation of sulfide to sulfoxide.As comparison,AU25 NCs simply located at the outer surface or insider matrix of UiO-66(short as Au2/UiO-66 and AU2s@UiO-66)show poor stability and low conversion,respectively.This structure regulated difference in the catalytic performances of three nanocomposites is assigned to the varied distribution of active sites(Au NCs)in metal-organic frameworks(MOFs).This work offers the opportunity for application of nanoclusters in catalysis,energy conversion and even biology.

Simultaneous H_2/H_∞ Stabilization for Chemical Reaction Systems Based on Orthogonal Complement Space

This paper presents a simultaneous H2/H∞ stabilization problem for the chemical reaction systems which can be modeled as a finite collection of subsystems. A single dynamic output feedback controller which simultaneously stabilizes the multiple subsystems and captures the mixed H2/H∞ control performance is designed. To ensure that the stability condition, the H2 characterization and the H∞ characterization can be enforced within a unified matrix inequality framework, a novel technique based on orthogonal complement space is developed. Within such a framework, the controller gain is parameterized by the introduction of a common free positive definite matrix, which is independent of the multiple Lyapunov matrices. An iterative linear matrix inequality （ILMI） algorithm using Matlab Yalmip toolbox is established to deal with the proposed framework. Simulation results of a typical chemical reaction system are exploited to show the validity of the proposed methodology.

Optical Activity of Chiral Metal Nanoclusters

CONSPECTUS:The emerging chirality in nanomaterials represents one of the most dynamic areas in modern science.Although many novel chiral nanomaterials have been reported,the origin of their chirality and related optical activity have been not unveiled unambiguously.Thanks to the fast development of noble metal cluster chemistry,the structures of many chiral nanoclusters(CNCs)have been precisely determined and their chirality origin has been decoded as four different levels including chiral ligand,helix staple motif,asymmetry metal kernel,and chiral arrangement of organic ligands.Generally,the strong optical activity associated with the electron transitions of the noble metal core is popularly reported among CNCs protected by chiral ligands,following the so-called“outside-in”chirality transfer theory,namely,from organic ligand to metal core.Exceptionally,inherent chiral structures are discerned inside CNCs consisting of achiral ligands,such as the helix staples found in Au38(SR)24 and Au102(SR)44(SR=thiolate)and the chiral metal kernel existing in Au20(PP3)4Cl4(PP3=tris(2-(diphenylphosphino)ethyl)phosphine).These chiral nanostructures induce distinct optical activity and even present reversed chirality transformation in the case of Au38(SR)24(i.e.,from chiral core structure to organic ligand).In the past decade,our group has carried out extensive research work on preparation,enantioseparation,optical activity,and application of chiral inorganic nanostructures.As representatives,enantiopure right-handed and left-handed Au20(PP3)4Cl4 clusters of intrinsic kernel chirality were acquired through an innovative supramolecular self-assembly method and their circular dichroism(CD)feature involving only the metal core was systematically studied;Au3[R/S-Tol-BINAP]3Cl(R/S-Tol-BINAP:R/S-2,2′-bis(di-p-tolylphosphino)-1,1′-binaphthyl)clusters with the smallest metal-atom number among the reported CNCs were designed and synthesized by using the privileged chiral Tol-BINAP ligand,which exhibited not only strongly enhanced CD signal also remarkable circular polarized luminescence(CPL)response as selfassembled into monodispersed nanocubes.In this Account,we aim at reviewing the fast development of CNCs featuring strong chiral attributes and optical activity.We will briefly introduce the preparation methods of CNCs,such as direct synthesis,ligand exchange,and enantioseparation.In the following parts,the commonly used tools for characterizing the chirality of CNCs are summarized,including CD,vibrational circular dichroism(VCD),CPL,single X-ray diffraction,nuclear magnetic resonance(NMR),and theoretical prediction.Then,the optical activity of CNCs will be systematically discussed,especially their CD,VCD,and CPL activity along with their chirality origin.Finally,future strategies for fabricating CNCs possessing strong optical activity as well as potential chirality-related applications will be proposed.We believe that this Account will trigger more research interest to not only study the amazing optical activity of CNCs but also employ them in many fields.

Soil liquefaction assessment by using hierarchical Gaussian Process model with integrated feature and instance based domain adaption for multiple data sources

For soil liquefaction prediction from multiple data sources,this study designs a hierarchical machine learning model based on deep feature extraction and Gaussian Process with integrated domain adaption techniques.The proposed model first combines deep fisher discriminant analysis(DDA)and Gaussian Process(GP)in a unified framework,so as to extract deep discriminant features and enhance the model performance for classification.To deliver fair evalu-ation,the classifier is validated in the approach of repeated stratified K-fold cross validation.Then,five different data resources are presented to further verify the model’s robustness and generality.To reuse the gained knowledge from the existing data sources and enhance the generality of the predictive model,a domain adaption approach is formu-lated by combing a deep Autoencoder with TrAdaboost,to achieve good performance over different data records from both the in-situ and laboratory observations.After comparing the proposed model with classical machine learn-ing models,such as supported vector machine,as well as with the state-of-art ensemble learning models,it is found that,regarding seismic-induced liquefaction prediction,the predicted results of this model show high accuracy on all datasets both in the repeated cross validation and Wilcoxon signed rank test.Finally,a sensitivity analysis is made on the DDA-GP model to reveal the features that may significantly affect the liquefaction.