全英文Tutorial教学对生物医学本科生学习行为方式影响的问卷调查与研究

全英文Tutorial教学是小班化问题导向式教学,旨在培养学生自主学习和解决问题能力。通过对浙江大学爱丁堡大学联合学院生物医学专业本科生个人和交互学习行为评价结果的比较分析,教师可探讨全英文Tutorial教学对生物医学本科生学习行为的效应,为学生培养提供新的经验。

高性能热固性聚酰亚胺树脂研究进展

热固性聚酰亚胺树脂基复合材料具有优异的耐热性和力学性能,广泛应用于武器装备、航空航天等领域。文中系统综述了热固性聚酰亚胺树脂及其复合材料的研究进展,介绍了国内外高性能热固性聚酰亚胺树脂的代表性成果,并对其未来的发展方向进行了展望。

聚酰亚胺基导热复合材料研究进展

聚酰亚胺(PI)具有优异的耐高低温性能、力学性能及耐腐蚀性能等,但其本征导热性能较差,限制了其在电子工业、航空、航天等领域应用的拓展。向PI中引入导热填料是提高材料导热性能的有效方法。文中概述了PI基导热复合材料的制备方法,归纳了导热填料在PI基体中的存在形式,即导热填料在PI基体中构筑的空间导热通路的维数(如:一维、二维、准三维及三维导热通路),并阐述了具有不同导热通路的PI基复合材料导热性能的表现,以及适用于PI复合材料的基本导热模型,最后展望了PI基导热复合材料未来的研究方向。

Argonaute protein as a linker to command center of physiological processes

MicroRNAs （miRNAs） post-transcriptionally regulate gene expression by binding to target mRNAs with perfect or imperfect complementarity, recruiting an Argonaute （AGO） protein complex that usually results in degradation or translational repression of the target mRNA. AGO proteins function as the Slicer enzyme in miRNA and small interfering RNA （siRNA） pathways involved in human physiological and pathophysiological processes, such as antiviral responses and disease formation. Although the past decade has witnessed rapid advancement in studies of AGO protein functions, to further elucidate the molecular mechanism of AGO proteins in cellular function and biochemical process is really a challenging area for researchers. In order to understand the molecular causes underlying the pathological processes, we mainly focus on five fundamental problems of AGO proteins, including evolution, functional domain, subcellular location, post-translational modification and protein-protein interactions. Our discussion highlight their roles in early diagnosis, disease prevention, drug target identification, drug response, etc.

Achieving a sub-10 nm nanopore array in silicon by metal-assisted chemical etching and machine learning

Solid-state nanopores with controllable pore size and morphology have huge application potential.However,it has been very challenging to process sub-10 nm silicon nanopore arrays with high efficiency and high quality at low cost.In this study,a method combining metal-assisted chemical etching and machine learning is proposed to fabricate sub-10 nm nanopore arrays on silicon wafers with various dopant types and concentrations.Through a SVM algorithm,the relationship between the nanopore structures and the fabrication conditions,including the etching solution,etching time,dopant type,and concentration,was modeled and experimentally verified.Based on this,a processing parameter window for generating regular nanopore arrays on silicon wafers with variable doping types and concentrations was obtained.The proposed machine-learning-assisted etching method will provide a feasible and economical way to process high-quality silicon nanopores,nanostructures,and devices.

Mapping of QTLs Associated with Seed Vigor to Artificial Aging Using Two RIL Populations in Maize (<i>Zea mays</i>L.)

Improvement in seed vigor under adverse condition is an important object in maize breeding nowadays. Because the higher sowing quality of seeds is necessary for the development of the agriculture production and better able to resist all kinds of adversity in the seeds storage. So it is helpful for long-term preservation of germplasm resource. In our study, two connected recombinant inbred line (RIL) populations, which derived from the crosses Yu82 × Shen137 and Yu537A × Shen137 respectively, were evaluated for four related traits of seed vigor under three aging treatments. Meta-analysis was used to integrate genetic maps and detected QTL across two populations. In total, 74 QTL and 20 meta-QTL (mQTL) were detected. All QTLs with contributions (R2) over 10% were consistently detected in at least one of aging treatments and integrated in mQTL. Four key mQTLs (mQTL2-2, mQTL5-3, mQTL6 and mQTL8) with R2 of some initial QTLs > 10% included 5-9 initial QTLs associated with 2-4 traits. Therefore, the chromosome regions for four mQTLs with high QTL co-localization might be hot spots of the important QTLs for the associated traits. Twenty-two key candidate genes regulating four related traits of seed vigor mapped in 14 corresponding mQTLs. In particular, At5g67360, 45238345/At1g70730/At1g09640 and 298201206 were mapped within the important mQTL5-3, mQTL6 and mQTL8 regions, respectively. Fine mapping or construction of single chromosome segment lines for genetic regions of the three mQTLs is worth further study and could be put to use molecular marker-assisted breeding and pyramiding QTLs in maize.

Analysis of system trustworthiness based on information flow noninterference theory

The trustworthiness analysis and evaluation are the bases of the trust chain transfer. In this paper the formal method of trustworthiness analysis of a system based on the noninterfer- ence （NI） theory of the information flow is studied. Firstly, existing methods cannot analyze the impact of the system states on the trustworthiness of software during the process of trust chain trans- fer. To solve this problem, the impact of the system state on trust- worthiness of software is investigated, the run-time mutual interfer- ence behavior of software entitles is described and an interference model of the access control automaton of a system is established. Secondly, based on the intransitive noninterference （INI） theory, a formal analytic method of trustworthiness for trust chain transfer is proposed, providing a theoretical basis for the analysis of dynamic trustworthiness of software during the trust chain transfer process. Thirdly, a prototype system with dynamic trustworthiness on a plat- form with dual core architecture is constructed and a verification algorithm of the system trustworthiness is provided. Finally, the monitor hypothesis is extended to the dynamic monitor hypothe- sis, a theorem of static judgment rule of system trustworthiness is provided, which is useful to prove dynamic trustworthiness of a system at the beginning of system construction. Compared with previous work in this field, this research proposes not only a formal analytic method for the determination of system trustworthiness, but also a modeling method and an analysis algorithm that are feasible for practical implementation.

The antioxidant protein ZmPrx5 contributes resistance to maize stalk rot

Maize(Zea mays L.)stalk rot is a devastating disease worldwide,causing severe yield losses.Although previous studies have focused on the genetic dissection of maize resistance to stalk rot,the mechanisms of resistance remain largely unknown.We used a comparative proteomics approach to identify candidate proteins associated with stalk rot resistance.Statistical analyses revealed 763 proteins differentially accumulated between Fusarium graminearum and mock-inoculated plants.Among them,the antioxidant protein ZmPrx5,which was up-accumulated in diseased plants,was selected for further study.ZmPrx5 transcripts were present in root,stalk,leaf,ear,and reproductive tissues.The expression of ZmPrx5 in three inbred lines increased significantly upon F.graminearum infection.ZmPrx5 was localized in the cytoplasm.Compared to control plants,maize plants overexpressing ZmPrx5 showed increased resistance to F.graminearum infection,and ZmPrx5 mutant plants were more susceptible than wild-type plants.Defense-associated pathways including plant–pathogen interactions,phenylalanine metabolism,and benzoxazinoid and flavonoid biosynthesis were suppressed in ZmPrx5 homozygous mutant plants compared with wild-type plants.We suggest that ZmPrx5 positively regulates resistance against stalk rot in maize,likely through defense-oriented transcriptome reprogramming.These results lay a foundation for further research on the roles of Prx5 subfamily proteins in resistance to plant fungal diseases,and provide a potential genetic resource for breeding disease-resistance maize lines.

发达国家农村金融发展的经验与启示

我国是一个农业大国,农业经济的发展关系到整个国民经济的发展。农业生产过程中存在很多风险。金融服务可以有效改善农业生产的经济不稳定性,降低农业生产中的风险,保障农民收入,从而实现乡村振兴。发达国家由于政府拥有有效的政治干预能力以及财政扶持能力,同时发达国家组织结构层级分明,基层之间遵循属地原则的特性,各国逐渐形成了具有自己特色的金融体系。本文从信贷、保险、金融体系构建等多方面对发达国家的农村金融体系进行探讨,这将对我国农村金融的发展具有启示作用。

Direct observation of oxygen vacancy formation and migration over ceria surface by in situ environmental transmission electron microscopy

The extremely high structural tolerance of ceria to oxygen vacancies(Ov)has made it a desirable catalytic material for the hydrocarbon oxidation to chemicals and pharmaceuticals and the reduction of gaseous pollutants.It is proposed that the formation and diffusion of Ov originate from its outstanding reduction property.However,the formation and diffusion process of Ov over the surface of ceria at the atomic level is still unknown.Herein,the structural and valence evolution of CeO_(2)(111)surfaces in reductive,oxidative and vacuum environments from room temperature up to 700℃was studied with in situ aberration-corrected environmental transmission electron microscopy(ETEM)experiments.Ov is found to form under a high vacuum at elevated temperatures;however,the surface can recover to the initial state through the adsorption of oxygen atoms in an oxygen-contained environment.Furthermore,in hydrogen environment,the step-CeO_(2)(111)surface is not stable at elevated temperatures;thus,the steps tend to be eliminated with increasing temperature.Combined with first-principles density function calculations(DFT),it is proposed that O-terminated surfaces would develop in a hypoxic environment due to the dynamic diffusion of Ov from the outer surface to the subsurface.Furthermore,in a reductive environment,H2 facilitates the formation and diffusion of Ov while Ce-terminated surfaces develope.These results reveal dynamic atomic-scale interplay between the nanoceria surface and gas,thereby providing fundamental insights into the Ov-dependent reaction of nano-CeO_(2) during catalytic processes.

Enhancing thermal conductivity of silicone rubber composites by insitu constructing SiC networks:A finite-element study based on first principles calculation

Polymer composites as thermal interface materials have been widely used in modern electronic equipment.In this work,we report a novel method to prepare highly through-plane thermally conductive silicone rubber(SR)composites with vertically aligned silicon carbide fibers(VA-SiCFs)entangled by SiC nanowires(SiCNWs)networks.First,a series of carbon fibers(CFs)skeletons were fabricated in sequence of coating poor thermally conductive polyacrylonitrile-based CFs with polydopamine,icetemplated assembly,and freeze-drying processes.Furthermore,VA-SiCFs networks,i.e.,long-range continuous SiCFs-SiCNWs networks,based on the prepared CFs skeletons,were in-situ obtained via template-assisted chemical vapor deposition method.The thermal conductivity enhancement mechanism of VA-SiCFs networks on its SR composites was also intensively studied by finite element simulation,based on the first principles investigation of SiC,and Foygel’s theory.The in-situ grown VA-SiCFs networks possess high intrinsic thermal conductivity without the thermal interface between fillers,acting as the high-efficiency through-plane long-range continuous thermal conduction path,in which the SiCNWs were the in-plane“thermal spreader”.The VA-SiCFs/SR composites reached a high through-plane thermal conductivity,2.13 W/(m·K),at the filler loading of 15 vol.%,which is 868.2%,and 249.2%higher than that of pure SR sample,and random-CFs@polydopamine(PDA)/SR composites at the same content,respectively.The VA-SiCFs/SR composites also exhibited good electrical insulation performance and excellent dimensional stability,which guaranteed the stable interfacial heat transfer of high-power density electronic devices.

局部消融术联合免疫检查点抑制剂治疗肝癌的研究进展

原发性肝细胞癌为常见恶性肿瘤之一。手术切除及肝移植术是根治性治疗手段,但多数肝癌患者确诊时已失去外科手术机会,不能外科手术的患者常采用局部消融治疗、肝动脉化疗栓塞术等微创治疗。近年来,肝癌的免疫治疗逐渐获得了国内外学者的关注。免疫检查点抑制剂(immune checkpoint inhibitors,ICIs)能减少肝癌微环境的免疫抑制,激活机体抗肿瘤免疫反应,控制并杀伤肿瘤细胞。局部消融术通过破坏肿瘤细胞来诱导机体免疫调节,以增强抗肿瘤免疫反应。因此,探究局部消融与ICIs协同增强抗肿瘤免疫反应的作用具有重要的临床意义。文章对局部消融联合ICIs治疗肝癌的研究现状及进展进行综述,并作出展望。

线粒体信使RNA基因变异分类标准解读

线粒体疾病受线粒体DNA和核基因组的双重调控,对线粒体DNA的变异解读一直充满挑战,本文将美国贝勒医学院临床医学遗传诊断室于2020年发表的线粒体信使RNA(mRNA)变异分类标准进行解读,以期为我国临床医生提供线粒体mRNA变异解读的最新依据。

The RppC-AvrRppC NLR-effector interaction mediates the resistance to southern corn rust in maize

Southern corn rust(SCR),caused by the fungal pathogen Puccinia polysora,is a major threat to maize pro-duction worldwide.Efficient breeding and deployment of resistant hybrids are key to achieving durable control of SCR.Here,we report the molecular cloning and characterization of RppC,which encodes an NLR-type immune receptor and is responsible for a major SCR resistance quantitative trait locus.Further-more,we identified the corresponding avirulence effector,AvrRppC,which is secreted by P.polysora and triggers RppC-mediated resistance.Allelic variation of AvrRppC directly determines the effectiveness of RppC-mediated resistance,indicating that monitoring of AvrRppC variants in the field can guide the rational deployment of RppC-containing hybrids in maize production.Currently,RppC is the most frequently deployed SCR resistance gene in China,and a better understanding of its mode of action is crit-ical for extending its durability.

Large-Scale Discovery of Non-conventional Peptides in Maize and Arabidopsis through an Integrated Peptidogenomic Pipeline

Non-conventional peptides(NCPs),which include small open reading frame-encoded peptides,play critical roles in fundamental biological processes.In this study,we developed an integrated peptidogenomic pipeline using high-throughput mass spectra to probe a customized six-frame translation database and applied it to large-scale identification of NCPs in plants.A total of 1993 and 1860 NCPs were unambiguously identified in maize and Arabidopsis,respectively.These NCPs showed distinct characteristics compared with conventional peptides and were derived from introns,3′UTRs,5′UTRs,junctions,and intergenic regions.Furthermore,our results showed that translation events in unannotated transcripts occur more broadly than previously thought.In addition,we found that dozens of maize NCPs are enriched within regions associated with phenotypic variations and domestication selection,indicating that they potentially are involved in genetic regulation of complex traits and domestication in maize.Taken together,our study developed an integrated peptidogenomic pipeline for large-scale identification of NCPs in plants,which would facilitate global characterization of NCPs from other plants.The identification of large-scale NCPs in both monocot(maize)and dicot(Arabidopsis)plants indicates that a large portion of plant genome can be translated into biologically functional molecules,which has important implications for functional genomic studies.

Overexpression of the Wounding-Responsive Gene AtMYB15 Activates the Shikimate Pathway in Arabidopsis

The MYB transcription factor genes play important roles in many developmental processes and various defense responses of plants. The shikimate pathway is a major biosynthetic pathway for the production of three aromatic amino acids and other aromatic compounds that are involved in multiple responses of plants, including protection against UV and defense. Herein, we describe the characterization of the R2R3-MYB gene AtMYB15as an activator of the shikimate pathway in Arabidopsis. The AtMYB15 protein is nuclear localized and a transcriptional activation domain is found in its C-terminal portion. Northern blots showed that AtMYB15 is an early wounding-inducible gene. Resutls of microarray analysis, confirmed using quantitative real-time polymerase chain reaction, showed that overexpression of AtMYB15 in transgenic plants resulted in elevated expression of almost all the genes involved in the shikimate pathway. Bioinformatics analysis showed that one or more AtMYB15-binding AC elements were detected in the promoters of these upregulated genes. Furthermore, these genes in the shikimate pathway were also found to be induced by wounding. These data suggest an important role of AtMYB15as a possible direct regulator of the Arabidopsis shikimate pathway in response to wounding.

Understanding the structural evolution of Au/WO_(2.7) compounds in hydrogen atmosphere by atomic scale in situ environmental TEM

Hydrogen energy is a resuscitated clean energy source and its sensitive detection in air is crucial due to its very low explosive limit.Metal oxide decorated with noble metal nanoparticles has been used for the enhancement of gas detection and exhibits superior sensitivity.Understanding the intrinsic mechanism of the detection and the enhancement mechanism is thus becoming a fundamental issue for the further development of novel metal/oxide compound gas-sensing materials.However,the correlation between the microstructural evolution,the charge transport and the complex sensing process has not yet been directly revealed and its atomic mechanism is still debatable.In this study,an Au/WO_(2.7) compound was synthesized and exhibited a strongly enhanced gas sensitivity to many reductive gases,especially H2.Aberration-corrected environmental transmission electron microscopy was used to investigate the atomic-scale microstructural evolution in situ during the reaction between H_(2) and Au/WO_(2.7) compound.Swing and sintering processes of the Au particles on the WO_(2.7) surface were observed under heating and gaseous environments,and no injection of hydrogen atoms was suggested.First principle calculations verified the swing and sintering processes,and they can be explained by the enhancement of H2 sensitivity.

Ascorbate peroxidase 1 confers resistance to southern corn leaf blight in maize

Southern corn leaf blight (SCLB), caused by Bipolarismaydis, is one of the most devastatingdiseases affecting maize production. However,only one SLCB resistance gene, conferring partialresistance, is currently known, underscoring theimportance of isolating new SCLB resistancerelatedgenes. Here, we performed a comparativeproteomic analysis and identified 258 proteinsshowing differential abundance during the maizeresponse to B. maydis. These proteins included anascorbate peroxidase (Zea mays ascorbate peroxidase1 (ZmAPX1)) encoded by a gene locatedwithin the mapping interval of a previously identifiedquantitative trait locus associated with SCLBresistance. ZmAPX1 overexpression resulted inlower H_(2)O_(2) accumulation and enhanced resistanceagainst B. maydis. Jasmonic acid (JA)contents and transcript levels for JA biosynthesisand responsive genes increased in ZmAPX1-overexpressing plants infected with B. maydis,whereas Zmapx1 mutants showed the oppositeeffects. We further determined that low levels of H_(2)O_(2) are accompanied by an accumulation of JAthat enhances SCLB resistance. These resultsdemonstrate that ZmAPX1 positively regulatesSCLB resistance by decreasing H_(2)O_(2) accumulationand activating the JA-mediated defensesignaling pathway. This study identified ZmAPX1as a potentially useful gene for increasing SCLBresistance. Furthermore, the generated datamay be relevant for clarifying the functions ofplant APXs.

Simultaneously enhanced oxidation resistance and mechanical properties in a novel lightweight Ti_(2)VZrNb_(0.5)-Al_(0.5)high-entropy alloy

Enhanced oxidation resistance is a primary demand for the application of refractory high-entropy alloys(RHEAs)at elevated temperatures.In this study,Al was added to a Ti_(2)VZrNb RHEA to partially substitute Nb to improve its oxidation resistance and mechanical properties.The alloy was found to have an increased oxidation resistance by forming a continuous Al_(2)O_(3)+ZrO_(2)oxide protective surface.At the same time,the room-temperature yield strength was also increased by 66%to 1273 MPa via solid solution strengthening.The low atomic mass of Al also helped to reduce the density of the alloy by 8.2%to 5.44 g cm^(−3).This resulted in a high specific yield strength of 234 MPa cm3 g^(−1) for the alloy.Meanwhile,the Ti_(2)VZrNb_(0.5)-Al_(0.5)alloy also exhibited a high compressive plasticity of>50%.These values are among the best reported so far for RHEAs.

Boron- and silicon-bridged bis(diphenylphosphino)-type ligands for chromium-catalyzed ethylene oligomerization

PNP-type ligands showed very good property in the catalytic systems of PNP/Cr(Ⅲ)/methylaluminoxane(MAO)for ethylene selective tetramerization toward1-octene.In this research,two PNP analogues bis(diphenylphosphino)phenylborane and bis(diphenylphosphino)dimethylsilane have been synthesized and characterized.In combination with CrCl3(THF)3as active center and MAO as cocatalyst,these ligands produced a new catalytic systems for ethylene oligomerization to linear α-olefins with catalytic activities of up to 3.07 9 106g mol-1(cat)h-1.Herein,we report the effects of the reaction temperature,ethylene pressure,and the molar ratio of Al/Cr on the catalyst activities and product selectivities.