A Federated Learning Framework with Blockchain-Based Auditable Participant Selection

Federated learning is an important distributed model training technique in Internet of Things(IoT),in which participant selection is a key component that plays a role in improving training efficiency and model accuracy.This module enables a central server to select a subset of participants to performmodel training based on data and device information.By doing so,selected participants are rewarded and actively perform model training,while participants that are detrimental to training efficiency and model accuracy are excluded.However,in practice,participants may suspect that the central server may have miscalculated and thus not made the selection honestly.This lack of trustworthiness problem,which can demotivate participants,has received little attention.Another problem that has received little attention is the leakage of participants’private information during the selection process.We will therefore propose a federated learning framework with auditable participant selection.It supports smart contracts in selecting a set of suitable participants based on their training loss without compromising the privacy.Considering the possibility of malicious campaigning and impersonation of participants,the framework employs commitment schemes and zero-knowledge proofs to counteract these malicious behaviors.Finally,we analyze the security of the framework and conduct a series of experiments to demonstrate that the framework can effectively improve the efficiency of federated learning.

Experimental study on the variation of optical remote sensing imaging characteristics of internal solitary waves with wind speed

Optical remote sensing has been widely used to study internal solitary waves(ISWs).Wind speed has an important effect on ISW imaging of optical remote sensing.The light and dark bands of ISWs cannot be observed by optical remote sensing when the wind is too strong.The relationship between the characteristics of ISWs bands in optical remote sensing images and the wind speed is still unclear.The influence of wind speeds on the characteristics of the ISWs bands is investigated based on the physical simulation experiments with the wind speeds of 1.6,3.1,3.5,3.8,and 3.9 m/s.The experimental results show that when the wind speed is 3.9 m/s,the ISWs bands cannot be observed in optical remote sensing images with the stratification of h_(1)∶h_(2)=7∶58,ρ_(1)∶ρ_(2)=1∶1.04.When the wind speeds are 3.1,3.5,and 3.8 m/s,which is lower than 3.9 m/s,the ISWs bands can be obtained in the simulated optical remote sensing image.The location of the band’s dark and light extremum and the band’s peak-to-peak spacing are almost not affected by wind speed.More-significant wind speeds can cause a greater gray difference of the light-dark bands.This provided a scientific basis for further understanding of ISW optical remote sensing imaging.

Development and validation of an analytical method for detecting chlorantraniliprole residues in fresh tea leaves

An efficient method using multiwalled carbon nanotubes(MWCNTs)as dispersive solid-phase extraction sorbent was established for determining chlorantraniliprole residues in fresh tea leaves,which are known to be a troublesome matrix containing abundant pigments,via gas chromatography with an electron capture detector.Acetonitrile was used as the extraction solvent,with sodium chloride enhancing the analyte partition in the organic phase.The optimal mixture of MWCNTs and primary secondary amine(PSA)was based on the distribution of the target analyte recovery and on the clean-up efficiency;while matrix-matched calibration was recommended to combat the matrix effect.Mean recoveries of 95.2%–108.8%were obtained with intraday and interday precisions of less than 7.9%and 10.3%,respectively.Good linearity was observed for concentrations of 0.02–1.0 mg/kg with a correlation coefficient of 0.9984.The limits of detection and quantification were 0.005 mg/kg and 0.02 mg/kg,respectively.The method was employed to investigate the dissipation dynamics of chlorantraniliprole in fresh tea leaves with real field samples.Consequently,the dissipation rates of chlorantraniliprole in fresh tea leaves followed pseudo-first-order kinetics with a half-life of 1.9 d,and the average chlorantraniliprole residue content was below 0.02 mg/kg with a harvest withholding period of 14 d.

Potato tonoplast sugar transporter 1 controls tuber sugar accumulation during postharvest cold storage

Cold-induced sweetening(CIS),the undesirable sugar accumulation in cold-stored potato(Solanum tuberosum L.)tubers,is a severe postharvest issue in the potato processing industry.Although the process of sucrose hydrolysis by vacuolar invertase during potato CIS is well understood,there is limited knowledge about the transportation of sucrose from the cytosol to the vacuole during postharvest cold storage.Here,we report that among the three potato tonoplast sugar transporters(TSTs),StTST1 exhibits the highest expression in tubers during postharvest cold storage.Subcellular localization analysis demonstrates that StTST1 is a tonoplast-localized protein.StTST1 knockdown decreases reducing sugar accumulation in tubers during low-temperature storage.Compared to wild-type,potato chips produced from StTST1-silenced tubers displayed significantly lower acrylamide levels and lighter color after cold storage.Transcriptome analysis manifests that suppression of StTST1 promotes starch synthesis and inhibits starch degradation in cold-stored tubers.We further establish that the increased sucrose content in the StTST1-silenced tubers might cause a decrease in the ABA content,thereby inhibiting the ABA-signaling pathway.We demonstrate that the down-regulation ofβ-amylase StBAM1 in StTST1-silenced tubers might be directly controlled by ABA-responsive element-binding proteins(AREBs).Altogether,we have shown that StTST1 plays a critical role in sugar accumulation and starchmetabolism regulation during postharvest cold storage.Thus,our findings provide a newstrategy to improve the frying quality of cold-stored tubers and reduce the acrylamide content in potato chips.

StRAP2.3, an ERF-Ⅶ transcription factor, directly activates StInvInh2 to enhance cold-induced sweetening resistance in potato

Potato invertase inhibitor(StInvInh2)positively regulates cold-induced sweetening(CIS)resistance by inhibiting the activity of vacuolar invertase.The distinct expression patterns of StInvInh2 have been thoroughly characterized in different potato genotypes,but the related CIS ability has not been characterized.The understanding of the regulatory mechanisms that control StInvInh2 transcription is unclear.In this study,we identified an ERF‐Ⅶ transcription factor,StRAP2.3,that directly regulates StInvInh2 to positively modulate CIS resistance.Acting as a nuclear-localized transcriptional activator,StRAP2.3 directly binds the ACCGAC cis-element in the promoter region of StInvInh2,enabling promoter activity.Overexpression of StRAP2.3 in CIS-sensitive potato tubers induced StInvInh2 mRNA abundance and increased CIS resistance.In contrast,silencing StRAP2.3 in CIS-resistant potato tubers repressed the expression of StInvInh2 and decreased CIS resistance.We conclude that cold-responsive StInvInh2 is due to the binding of StRAP2.3 to the ACCGAC cis-element in the promoter region of StInvInh2.Overall,these findings indicate that StRAP2.3 directly regulates StInvInh2 to positively modulate CIS resistance,which may provide a strategy to improve the processing quality of potatoes.

Illumina MiSeq sequencing investigation of Chanhua (Cordyceps cicadae Shing) fungal community structures in different regions

Objective:This study was carried out to elucidate the fungal diversity of Chanhua (Cordyceps cicadae Shing),which is an entomogenous fungal parasite that grows on wingless cicada nymphs.Methods:Samples were collected from 10 different geographical regions including Yibing in Sichuan Province,Jiangsu Province,Jiangxi Province,Anhui Province,Guangdong Province,and Guangxi Autonomous Region.The Illumina MiSeq-based method was used to investigate the Chanhua fungal community structures.Results:The results showed high fungal diversity,with 22 families found in the different samples,Eurotiomycetes was the dominant fungal family associated with Chanhua (composing 36.69% of the sample from Sichuan Mianyang),whereas Cordycipitaceae only composed 0.51% (Sichuan Yibing) to 0.33% (Guangdong) of these samples.Surprisingly,the proportion of Capnodiales was 5.27% in Sichuan Mianyang,whereas the percentage in other regions ranged from 4.35% (Sichuan Yibing) to 2.55% (Zhejiang),and the remaining proportion (more than 80%) was made up of unidentified fungus.Conclusions:These findings contribute to a better understanding of Chanhua from different regions and revealed an unexpectedly and high amount of unidentified diversity of these fungal communities.These results indicate that Chanhua parasitic fungi need to be further analyzed and identified for finding new medical fungi resources.

Determination of 18 Kinds of Amino Acids in Fresh Tea Leaves by HPLC Coupled with Pre-column Derivatization

A rapid and accurate quantitative method of high performance liquid chromatography( HPLC) with fluorescence detector has been developed for the analysis of 18 kinds of amino acids in fresh tea leaves. The samples were minced and mixed,and extracted with ultra pure water at 90℃ for 20 min. The 6-aminoquinolyl N-hydroxy-succinimidyl carbamate( AQC) was used as pre-column derivatization reagent. Gradient HPLC separation was performed on a C_(18) column( Symmetry C_(18),3. 9 mm × 15 cm,4 μm). Good linearity between concentrations and peak areas was achieved in the concentration range of 5. 0-250 μmol/L for 18 kinds of amino acids. The method was validated by the analysis of five replicates. The 18 kinds of amino acid standards were spiked in fresh tea leaf samples and the average recovery rate was 86. 25%-109. 05% with relative standard deviations( n = 5) ranging from 6. 03% to 10. 56%. The limit of detection( LOD) for the analytes was0. 05-1. 27 μmol/L. The method was successfully applied to the analysis of the 18 kinds of amino acids in fresh tea leaves from east Dongting and west Dongting mountains in Suzhou. The results indicate that the method is simple,rapid,precise and reliable.

Dissipation Kinetics of Chlorpyrifos in Soils of a Vegetable Cropping System under Different Cultivation Conditions

Dissipation kinetics of chlorpyrifos in the near-neutral paddy soils of a vegetable cropping system under greenhouse, screenhouse and field conditions was studied using a rapid analytical method. The recoveries of chlorpyrifos were between 86.5% and 105.5% with relative standard deviations for repeatability between 6.6% and 9.1% at fortification levels of 0.01, 0.1 and 1 mg/kg in the soil. The limit of detection of the method was 0.004 mg/kg and the limit of quantification was found to be 0.01 mg/kg. The dissipation rates of chlorpyrifos followed the first-order kinetics and the half-life was 6.96, 6.04 and 5.20 days in the soil under greenhouse, screenhouse and field conditions, respectively. The dissipation rates of chlorpyrifos in the soil varied with different cultivation conditions. Chlorpyrifos in the soil dissipated slower in a greenhouse and screenhouse than in the open field, which was likely attributed to the hermetic environment in the greenhouse and screenhouse.

高水平临床研究推动肺动脉高压危险分层内涵发展

肺动脉高压是一种疑难危重罕见病,一直以来被视为“心血管系统的癌症”,患者预后极差.对疾病进行危险分层可以帮助临床医生判断患者病情、指导治疗、评价疗效和预测预后,这需要大量的临床研究作为依据.高水平临床研究是解决临床实践问题的重要手段,我国肺动脉高压队列有着独特的特点,学习和借鉴国外肺动脉高压危险分层发展经验,对建立符合我国肺动脉高压人群的危险分层具有重要意义.本文以肺动脉高压危险分层发展为例,旨在深入剖析通过高水平临床研究解决临床问题的过程与方法.文章概述了肺动脉高压的发现与流行,明确了定义与深入开展临床研究的全过程;重点围绕靶向药治疗时代下肺动脉高压危险分层的建立与更新,总结临床研究推动肺动脉高压诊疗指南和治疗理念不断发展的方式方法;最后通过分析肺动脉高压危险分层在我国的应用现状和问题,希望国外研究肺动脉高压危险分层的思维方式对我国开展临床研究、解决临床实践中的问题有所启示.

Duplication and sub-functionalization of flavonoid biosynthesis genes plays important role in Leguminosae root nodule symbiosis evolution

Gene innovation plays an essential role in trait evolution.Rhizobial symbioses,the most important N2-fixing agent in agricultural systems that exists mainly in Leguminosae,is one of the most attractive evolution events.However,the gene innovations underlying Leguminosae root nodule symbiosis(RNS)remain largely unknown.Here,we investigated the gene gain event in Leguminosae RNS evolution through comprehensive phylogenomic analyses.We revealed that Leguminosae-gain genes were acquired by gene duplication and underwent a strong purifying selection.Kyoto Encyclopedia of Genes and Genomes analyses showed that the innovated genes were enriched in flavonoid biosynthesis pathways,particular downstream of chalcone synthase(CHS).Among them,Leguminosae-gain typeⅡchalcone isomerase(CHI)could be further divided into CHI1A and CHI1B clades,which resulted from the products of tandem duplication.Furthermore,the duplicated CHI genes exhibited exon–intron structural divergences evolved through exon/intron gain/loss and insertion/deletion.Knocking down CHI1B significantly reduced nodulation in Glycine max(soybean)and Medicago truncatula;whereas,knocking down its duplication gene CHI1A had no effect on nodulation.Therefore,Leguminosae-gain typeⅡCHI participated in RNS and the duplicated CHI1A and CHI1B genes exhibited RNS functional divergence.This study provides functional insights into Leguminosae-gain genetic innovation and sub-functionalization after gene duplication that contribute to the evolution and adaptation of RNS in Leguminosae.

Profiling of Phakopsora pachyrhizi transcriptome revealed co-expressed virulence effectors as prospective RNA interference targets for soybean rust management

Soybean rust(SBR),caused by an obligate biotrophic pathogen Phakopsora pachyrhizi,is a devastating disease of soybean worldwide.However,the mechanisms underlying plant invasion by P.pachyrhizi are poorly understood,which hinders the development of effective control strategies for SBR.Here we performed detailed histological characterization on the infection cycle of P.pachyrhizi in soybean and conducted a high-resolution transcriptional dissection of P.pachyrhizi during infection.This revealed P.pachyrhizi infection leads to significant changes in gene expression with 10 co-expressed gene modules,representing dramatic transcriptional shifts in metabolism and signal transduction during different stages throughout the infection cycle.Numerous genes encoding secreted protein are biphasic expressed,and are capable of inhibiting programmed cell death triggered by microbial effectors.Notably,three co-expressed P.pachyrhizi apoplastic effectors(PpAE1,PpAE2,and PpAE3) were found to suppress plant immune responses and were essential for P.pachyrhizi infection.Double-stranded RNA coupled with nanomaterials significantly inhibited SBR infection by targeting PpAE1,PpAE2,and PpAE3,and provided long-lasting protection to soybean against P.pachyrhizi.Together,this study revealed prominent changes in gene expression associated with SBR and identified P.pachyrhizi virulence effectors as promising targets of RNA interference-based soybean protection strategy against SBR.

Engineered exosome hybrid copper nanoscale antibiotics facilitate simultaneous self-assembly imaging and elimination of intracellular multidrug-resistant superbugs

With the increasing emergence of bacterial infections,especially multidrug-resistant(MDR)bacteria,poses an urgent threat.This study demonstrated a novel multifunctional nanotheranostics platform developed by the strategic integration of both in-situ bio-assembly imaging and target bacteria inactivation.Through the introduction of copper ions into bacteria,the Cu^(2+)could spontaneously bio-selfassembled into a multifunctional copper nanoclusters(NCs)which efficiently enhanced epigallocatechin gallate(EGCG)uptake into bacteria.While visualizing the bacteria,the developed theranostic nanoplatform exhibited highly efficient disinfection activities with negligible side effects as reflected by higher cell viability and insignificant hemolytic effects.Furthermore,the exosomal formulation of EGCG integrated with Cu^(2+)showed an increased intracellular antibacterial activity,which could eliminate most of the methicillin-resistant Staphylococcus aureus(MRSA)phagocytosed by macrophages,guide macrophages toward M2-like phenotype polarization and alleviate inflammation,without exhibiting obvious cytotoxicity on host RAW264.7.The regimen could be viewed as an effective strategy for the sterilization of intractable bacterial infections.

Dual activation of soybean resistance against Phytophthora sojae by pectin lyase and degraded pectin oligosaccharides

Phytophthora pathogens secrete numerous apoplastic effectors to manipulate host immunity.Herein,we identified a polysaccharide lyase 1 protein,PsPL1,which acts as an essential virulence factor of P.sojae infection in soybean.However,the overexpression of PsPL1 in P.sojae reduced infection and triggered enhanced immune responses in soybean.PsPL1 exhibited pectin lyase activity and degraded plant pectin to generate pectin oligosaccharides(POSs)with a polymerization degree of 3–14,exhibiting different levels of acetylation and methylation modifications.PsPL1 and the degraded pectin products triggered immune responses in soybean and different Solanaceous plants.The PsPL1-triggered immune responses required RSPL1,a membrane-localized leucine-rich repeat receptor-like protein,which is essential for Phytophthora resistance.Conversely,the PsPL1-degraded product-triggered immune responses depended on the membrane-localized lysin motif receptor-like kinase CERK1.This study reveals that the pectin lyase exhibits a dual immunogenic role during P.sojae infection,which activates plant resistance through different immune receptors and provides novel insights into the function of pectin lyase in host-pathogen interactions.

新型耐热β-1,4-木糖苷酶的重组表达及酶学性质

【目的】拟对来源于热解纤维素果汁杆菌的新型β-木糖苷酶基因(CoXyl B)进行重组表达和酶学性质研究。【方法】在大肠杆菌系统中成功表达CoXyl B基因,并通过镍柱亲和层析、强阴离子交换和凝胶层析等纯化方法获得纯酶。【结果】对CoXyl B酶学性质的研究结果显示,在以4-对硝基苯酚-β-D-木糖苷为底物时,该酶的最适反应温度为90℃,最适反应pH为6.0。在40–70℃范围内CoXyl B酶活较高且比较稳定。在pH 5.0–6.0之间,70℃孵育1 h后,CoXyl B的相对酶活仍保留80%以上。Ag^+、高浓度的SDS和PMSF对酶活力的抑制作用较显著,而高浓度Mg^(2+)、Li^+和EDTA对酶活力的激活作用较为明显。CoXyl B的k_(cat)和K_m值分别为5.0×10^(–3)s^(–1)和1.9 mmol/L。薄层层析色谱显示CoXyl B具有降解木二糖、木三糖和木四糖的能力。【结论】本研究鉴定出CoXyl B为一种新型的极端耐热木糖苷酶,CoXyl B的酶学性质研究将为其在食品热加工以及生物降解领域中的应用提供参考。

外源物质对茶树耐寒及蔗糖代谢关键基因表达的影响

冬春季节低温伤害是影响茶树(Camellia sinensis)生产的重要因素。以茶树盆栽苗为试验材料,通过喷施不同浓度的γ-氨基丁酸(GABA)、绿藻粉和竹醋液溶液,研究低温胁迫下3种外源物质对茶树耐寒能力的影响,并对蔗糖代谢关键基因SPS、SUS4、INV4和INV5表达量及耐寒相关生理指标进行分析,解析外源物质影响茶树耐寒性的生理与分子机制。结果表明,低温胁迫下,用不同浓度GABA、绿藻粉和竹醋液喷施处理茶树盆栽苗叶片,其冻害指数和相对电导率显著低于对照;可溶性糖含量显著高于对照,以10 mmol·L^–1 GABA、0.22 mg·mL^–1绿藻粉及2.5 mg·mL^–1竹醋液处理效果最佳。低温胁迫下,与清水处理相比,分别用10 mmol·L^–1 GABA、0.22 mg·mL^–1绿藻粉或2.5 mg·mL^–1竹醋液处理茶树盆栽苗后,茶树苗丙二醛含量显著降低,抗氧化酶活性显著提高;叶片叶绿素、可溶性糖和脯氨酸含量显著增加,蔗糖含量在处理72小时后分别增加了15.24%、11.39%和5.97%;SPS、SUS4、INV4和INV5基因的表达量显著升高。实验结果表明,GABA、绿藻粉和竹醋液能显著增强茶树的耐寒性。研究结果可为茶树抗寒剂的筛选提供理论依据。

Epigenetic regulation of macrophage polarization in wound healing

The immune microenvironment plays a critical role in regulating skin wound healing.Macrophages,the main component of infiltrating inflammatory cells,play a pivotal role in shaping the immune microenvironment in the process of skin wound healing.Macrophages comprise the classic proinflammatory M1 subtype and anti-inflammatory M2 population.In the early inflammatory phase of skin wound closure,M1-like macrophages initiate and amplify the local inflammatory response to disinfect the injured tissue.In the late tissue-repairing phase,M2 macrophages are predominant in wound tissue and limit local inflammation to promote tissue repair.The biological function of macrophages is tightly linked with epigenomic organization.Transcription factors are essential for macrophage polarization.Epigenetic modification of transcription factors determines the heterogeneity of macrophages.In contrast,transcription factors also regulate the expression of epigenetic enzymes.Both transcription factors and epigenetic enzymes form a complex network that regulates the plasticity of macrophages.Here,we describe the latest knowledge concerning the potential epigenetic mechanisms that precisely regulate the biological function of macrophages and their effects on skin wound healing.

CRISPR/Cas9-mediated editing of GmTAP1 confers enhanced resistance to Phytophthora sojae in soybean

Soybean(Glycine max) is an economically important oilbearing crop that is widely planted worldwide(Babu et al.,2017). Many diseases seriously limit soybean yield. Soybean root rot disease, one of the most destructive soybean diseases, occurs throughout the growth period, resulting in considerable yield losses(Kamoun et al., 2015).

3D Printing of Continuous Fiber Reinforced Polymer Composites:Development,Application,and Prospective

Continuous fiber reinforced polymer composites(CFRPC)have been widely used in the field of automobile,air-craft,and space due to light weight,high specific strength and modulus in comparison with metal as well as alloys.Innovation on 3D printing of CFRPCs opened a new era for the design and fabrication of complicated composite structure with high performance and low cost.3D printing of CFRPCs provided an enabling technol-ogy to bridge the gaps between advanced materials and innovative structures.State-of-art has been reviewed according to the correlations of materials,structure,process,and performance as well as functions in 3D printing of CFRPCs.Typical applications and future perspective for 3D printing of CFRPCs were illustrated in order to grasp the opportunities and face the challenges,which need much more interdisciplinary researches covering the advanced materials,process and equipment,structural design,and final smart performance.

Synthesis of graphene oxide-quaternary ammonium nanocomposite with synergistic antibacterial activity to promote infected wound healing

Background: Bacterial infection is one of the most common complications in burn, trauma, and chronic refractory wounds and is an impediment to healing. The frequent occurrence of antimicrobial-resistant bacteria due to irrational application of antibiotics increases treatment cost and mortality. Graphene oxide (GO) has been generally reported to possess high antimicrobial activity against a wide range of bacteria in vitro. In this study, a graphene oxide-quaternary ammonium salt (GO-QAS) nanocomposite was synthesized and thoroughly investigated for synergistic antibacterial activity, underlying antibacterial mechanisms and biocompatibility in vitro and in vivo. Methods: The GO-QAS nanocomposite was synthesized through amidation reactions of carboxylic group end-capped QAS polymers with primary amine-decorated GO to achieve high QAS loading ratios on nanosheets. Next, we investigated the antibacterial activity and biocompatibility of GO-QAS in vitro and in vivo. Results: GO-QAS exhibited synergistic antibacterial activity against bacteria through not only mechanical membrane perturbation, including wrapping, bacterial membrane insertion, and bacterial membrane perforation, but also oxidative stress induction. In addition, it was found that GO-QAS could eradicate multidrug-resistant bacteria more effectively than conventional antibiotics. The in vitro and in vivo toxicity tests indicated that GO-QAS did not exhibit obvious toxicity towards mammalian cel s or organs at low concentrations. Notably, GO-QAS topically applied on infected wounds maintained highly efficient antibacterial activity and promoted infected wound healing in vivo. Conclusions: The GO-QAS nanocomposite exhibits excellent synergistic antibacterial activity and good biocompatibility both in vitro and in vivo. The antibacterial mechanisms involve both mechanical membrane perturbation and oxidative stress induction. In addition, GO-QAS accelerated the healing process of infected wounds by promoting re-epithelialization and granulation tissue formation. Overall, the results indicated that the GO-QAS nanocomposite could be applied as a promising antimicrobial agent for infected wound management and antibacterial wound dressing synthesis.

De Novo Biosynthesis of Vindoline and Catharanthine in Saccharomyces cerevisiae

Vinblastine has been used clinically as one of the most potent therapeutics for the treatment of several types of cancer.However,the traditional plant extraction method suffers from unreliable supply,low abundance,and extremely high cost.Here,we use synthetic biology approach to engineer Saccharomyces cerevisiae for de novo biosynthesis of vindoline and catharanthine,which can be coupled chemically or biologically to vinblastine.On the basis of a platform strain with sufficient supply of precursors and cofactors for biosynthesis,we reconstituted,debottlenecked,and optimized the biosynthetic pathways for the production of vindoline and catharanthine.The vindoline biosynthetic pathway represents one of the most complicated pathways ever reconstituted in microbial cell factories.Using shake flask fermentation,our engineered yeast strains were able to produce catharanthine and vindoline at a titer of 527.1 and 305.1μg·liter^(−1),respectively,without accumulating detectable amount of pathway intermediates.This study establishes a representative example for the production of valuable plant natural products in yeast.