The life-history trait trade-offs mediated by reproduction and immunity in the brown planthopper,Nilaparvata lugens Stål

Reproduction and immune defense are costly functions,and they are expected to tradeoff with each other to drive evolution.The brown planthopper(BPH),Nilaparvata lugens Stål(Hemiptera,Delphacidae),is a global superpest that mostly damages rice crops.Yeast-like symbionts(YLS)exist in the abdominal fat body tissue and are tightly associated with the development,growth,and reproduction of BPH.Our previous research demonstrated that mating behavior promotes the release of YLS from the fat body into the hemolymph in the BPH,thereby triggering an immune response.Additionally,the fitness costs related to life-history traits of BPH(such as survival rate)have a strong dependence on the relative abundance of YLS.However,the possible relationship between reproduction and the immune response in BPH has not been identified.In this study,an omics-based approach was used to analyze the transcriptome of fat body tissues in mated and unmated BPH at 72 h post-eclosion,from which two antimicrobial peptide genes,NlDefensin A(NlDfA)and NlDefensin B(NlDfB),were selected since they were highly expressed in mated BPH.Subsequently,the full-length cDNA sequences of the NlDfA and NlDfB genes were cloned and analyzed.qPCR results showed up-regulation of the NlDfA and NlDfB genes in mated BPH when compared to unmated BPH.Spatial-temporal expression analysis indicated that the NlDfA and NlDfB genes were expressed in all tissues and developmental stages,and they were most highly expressed in the fat body at 24 h post-eclosion.Moreover,the symbionts in BPH were significantly inhibited by the in vitro expression of the NlDfA and NlDfB proteins.Furthermore,RNA interference(RNAi)-mediated suppression of NlDfA and NlDfB dramatically increased the relative abundance of YLS in the fat body,while YLS in the hemolymph decreased significantly.These BPHs also displayed some fitness disadvantages in survival,fecundity,hatchability,and possibly the vertical transmission of YLS from hemolymph to egg.Our results indicated that mating could heighten the immunity of BPH by upregulating the expression of the NlDfA and NlDfB genes,which protect the host from pathogen challenges during reproduction.However,the reduced content of YLS may act as a fitness disadvantage in dictating the life-history traits of BPH.This work has significant theoretical and practical implications for the precise green control technology that involves crucial gene targeting,as well as for the“endosymbionts for pest control”strategy in insects.

Effect of grain size on gas bubble evolution in nuclear fuel:Phase-field investigations

Numerous irradiation-induced gas bubbles are created in the nuclear fuel during irradiation, leading to the change of microstructure and the degradation of mechanical and thermal properties. The grain size of fuel is one of the important factors affecting bubble evolution. In current study, we first predict the thermodynamic behaviors of point defects as well as the interplay between vacancy and gas atom in both UO_(2) and U_(3)Si_(2) according to ab initio approach. Then, we establish the irradiation-induced bubble phase-field model to investigate the formation and evolution of intra-and inter-granular gas bubbles. The effects of fission rate and temperature on the evolutions of bubble morphologies in UO_(2) and U_(3)Si_(2) have been revealed. Especially, a comparison of porosities under different grain sizes is examined and analyzed. To understand the thermal conductivity as functions of grain size and porosity, the heat transfer capability of U_(3)Si_(2) is evaluated.

抑制植物减数分裂重组的分子机理

减数分裂重组不仅保证了真核生物有性生殖过程中染色体数量的稳定,还通过父母亲本间遗传物质的互换在后代中产生遗传变异。因此,减数分裂重组是遗传多样性形成的重要途径,也是生物多样性和物种进化的主要动力。在绝大多数真核生物中,不管染色体数目的多少或基因组的大小,减数分裂重组的形成都受到严格的调控,但抑制减数分裂重组的分子机理目前仍不清楚。近年来,通过正向遗传学筛选鉴定出多个减数分裂重组抑制基因,揭示了抑制基因的功能和调控途径。本文基于拟南芥中减数分裂重组抑制基因的研究现状,综述了植物减数分裂重组抑制基因研究取得的突破性进展,并结合基因功能与其调控网络阐述了抑制植物减数分裂重组的分子机理。

锌金属电镀过程中锌枝晶的生长行为及影响因素

电镀是电化学体系的重要组成部分。为拓宽学生的知识构架,培养学生的创新意识和科学素养,将锌电镀引入应用电化学专业本科实验教学。本实验以锌电镀过程中易产生锌枝晶的问题为出发点,先从理论上剖析其形成原因,据此提出表面异质性消除以及阳离子添加剂两种策略来抑制锌枝晶的产生;并设计通过搭建原位光学显微镜直接观测锌沉积行为变化,以加深学生对锌电镀过程的理解。本实验深入融合贯穿了前沿研究的科学思路与创新理念,引导学生跳出教材内容的框架,激发学生对科学研究的兴趣,有助于学生科学思维能力的培养。

蜂窝密封泄漏特性与动力特性影响因素分析

结构参数与进口预旋对蜂窝密封静力与动力特性有较大影响。建立了蜂窝密封动力特性求解模型,在验证数值求解模型准确性的基础上,研究蜂窝芯格尺寸、轴向长度和进口预旋对密封性能的影响。结果表明,当蜂窝芯格尺寸相同时,密封有效刚度系数和有效阻尼系数随着轴向长度增加而增大;随着预旋比的增大,气流周向分量增大,轴向分量减小,故泄漏量逐渐减少;随着进口预旋的增大,蜂窝密封有效阻尼系数减小,主要是密封周向旋流增强,导致气流周向压力分布不均匀,从而降低了蜂窝密封的稳定性。

Analysis of risk factors for the interval time, number and pattern of hepatic metastases from gastric cancer after radical gastrectomy

AIM: To analyze the risk factors for interval time, number and pattern of hepatic metastases from gastric cancer after radical gastrectomy, and provide evidence for predicting and preventing hepatic metastasis from gastric cancer after radical gastrectomy. METHODS: A retrospective study of 87 patients with hepatic metastasis who underwent radical gastrectomy for gastric cancer from 1996 to 2001. The data was analyzed to evaluate significant risk factors for interval time, number and pattern of hepatic metastases originating from gastric cancer after radical gastrectomy. RESULTS: The size of gastric cancer and lymph node metastases were independently correlated with the interval time of hepatic metastases; the depth of invasion was independently correlated with the number of hepatic metastases; while the depth of invasion and Lauren classification were independently correlated with the pattern of hepatic metastases. CONCLUSION: We evaluated the interval time of hepatic metastases with the size of gastric cancer and lymph node metastases. The depth of invasion could be used to evaluate the number of hepatic metastases, while the depth of invasion and the Lauren classification could be used to evaluate the pattern of hepatic metastases in patients who underwent radical gastrectomy.

Fast mapping of a chlorophyll b synthesis-deficiency gene in barley(Hordeum vulgare L.) via bulked-segregant analysis with reduced-representation sequencing

Bulked-segregant analysis coupled with next-generation sequencing(BSA-seq) has emerged as an efficient tool for genetic mapping of single genes or major quantitative trait loci controlling(agronomic) traits of interest. However, such a mapping-by-sequencing approach usually relies on deep sequencing and advanced statistical methods. Application of BSA-Seq based on construction of reduced-representation libraries and allele frequency analysis permitted anchoring the barley pale-green(pg) gene on chromosome 3 HL. With further marker-assisted validation, pg was mapped to a 3.9 Mb physical-map interval. In the pg mutant a complete deletion of chlorophyllide a oxygenase(HvCAO) gene was identified.Because the product of this gene converts Chl a to Chl b, the pg mutant is deficient in Chl b.An independent Chl b-less mutant line M4437_2 carried a nonsynonymous substitution(F263 L) in the C domain of HvCAO. The study demonstrates an optimized pooling strategy for fast mapping of agronomically important genes using a segregating population.

Issues and solutions toward zinc anode in aqueous zinc-ion batteries: A mini review

Aqueous zinc-ion batteries(ZIBs)have been intensively investigated as potential energy storage devices on account of their low cost,environmental benignity,and intrinsically safe merits.With the exploitation of highperformance cathode materials,electrolyte systems,and in-depth mechanism investigation,the electrochemical performances of ZIBs have been greatly enhanced.However,there are still some challenges that need to be overcome before its commercialization.Among them,the obstinate dendrites,corrosion,and hydrogen evolution reaction(HER)on Zn anodes are critical issues that severely limit the practical applications of ZIBs.To address these issues,various strategies have been proposed,and tremendous progress has been achieved in the past few years.In this article,we analyze the origins and effects of the dendrites,corrosion,and HER on Zn anodes in neutral and mildly acid aqueous solutions at first.And then,a scientific understanding of the fundamental design principles and strategies to suppress these problems are emphasized.Apart from these,this article also puts forward some requirements for the practical applications of Zn anodes as well as several cost-effectivemodifying strategies.Finally,perspectives on the future development of Zn anodes in aqueous solutions are also briefly anticipated.This article provides pertinent insights into the challenges on anodes for the development of highperformance ZIBs,which will greatly contribute to their practical applications.

Study on inverter fault-tolerant operation of PMSM DTC

This paper presents an investigation of inverter fault-tolerant operation for a permanent magnet synchronous motor （PMSM） direct torque control （DTC） system under various inverter faults. The performance of a faulty standard 6-switch inverter driven PMSM DTC system is analyzed. To avoid the loss or even disaster caused by the inverter faults, a topology-modified inverter with fault-tolerant capability is introduced, which is reconfigured as a 3-phase 4-switch inverter. The modeling of the 4-switch inverter is then analyzed and a novel DTC strategy with a unique nonlinear perpendicular flux observer and feedback compensation scheme is proposed for obtaining a continuous, disturbance-flee drive system. The simulation and experimental results demonstrate that the proposed inverter fault-tolerant PMSM DTC system is able to operate stably and continuously with acceptable static and pretty good dynamic performance.

Power Allocation for Cooperative Communications in Non-Orthogonal Cognitive Radio Vehicular Ad-Hoc Networks

To achieve the better system performance for cooperative communication in non-orthogonal cognitive radio vehicular adhoc networks(CR-VANETs),this paper investigates the power allocation considering the interference to the main system in a controllable range.We propose a three-slot one-way vehicle system model where the mobile vehicle nodes complete information interaction with the assistance of other independent nodes by borrowing the unused radio spectrum with the primary networks.The end-to-end SNR relationship in overlay and underlay cognitive communication system mode are analyzed by using two forwarding protocol,namely,decode-and-forward(DF)protocol and amplify-and-forward(AF)protocol,respectively.The system outage probability is derived and the optimal power allocation factor is obtained via seeking the minimum value of the approximation of system outage probability.The analytical results have been confirmed by means of Monte Carlo simulations.Simulation results show that the proposed system performance in terms of outage under the optimal power allocation is superior to that under the average power allocation,and is also better than that under other power allocation systems.

多级低滞后型刷式密封流动传热特性数值研究

多级低滞后刷式密封的级间压力均衡性和传热特性影响其密封性能和使用寿命。本文建立了基于三维实体建模的多级低滞后刷式密封传热特性求解模型,在验证数值模型准确性的基础上,数值分析了不同压比条件下多级低滞后型刷式密封的级间压力分布特性,研究了两级和三级低滞后型刷式密封温度分布特性。研究结果表明:两级和三级低滞后型刷式密封的最大级间压降均出现在末级刷丝,压比对级间压降占比的影响较小;两级和三级低滞后型刷式密封刷丝束温度逐级升高,末排刷丝温度最高,这主要是因为泄漏气流将前级刷丝束的热量带至末排,导致末排刷丝温度较高,末排刷丝的热变形量最大;刷式密封的热量主要来源是由刷丝与转子之间摩擦产生,其传热形式包括刷丝与挡板、转子之间的导热,以及刷丝、转子、挡板与气流之间的对流换热;刷丝与转子之间的接触力大小决定了摩擦产生的热量大小,导致最高温度不同;热量散失的主要形式是泄漏气流带走的热量。

“鸡尾酒”实验——无机元素化学实验中美育迁移作用的探索

以“美育”内涵中“培养发现美的能力”为契合点,借助大一新生在无机元素化学实验中发现美时获取的成就感,引导学生在追求“美丽”实验结果的过程中,自发地对基本操作进行训练和提高,由此发挥美育在无机化学实验教学过程中的迁移作用。以钴离子形成多色配合物为“点”,带动学生持续发现实验中更多的“美”,逐步培养细心、耐心和恒心的素养。同时,在新高考、新生源背景下,注重大一新生化学学习兴趣的提高,将直接影响到其对专业的认知及职业的认同,因而其积极作用是不容忽视且意义深远的。

Identification and Expression of TOP3αin Gerbera hybrida

Meiotic recombination and the resulting novel allele combinations are fundamental to plant breeding and the identification of superior hybrids.However,the rate of meiotic crossovers is naturally suppressed below its potential ability,which prevents plant breeding efficiency.Nine suppressors of meiotic recombination have been identified in the model plant Arabidopsis and in other crop species.Mutations in these genes can lead to increased recombination frequency and could therefore potentially be used to create hyper-recombinant lines for ornamental breeding.In Gerbera hybrida,the anti-crossover factors remain elusive.In this study,we isolated and cloned TOP3αfrom flower buds of G.hybrida,and it encoded 935 amino acids with three conserved domains TOPRIM,TOP1Ac and zf-GR.Moreover,TOP3αwas the highest expressed at the flower bud stage,which coincided with the occurrence of meiotic recombination,suggesting that TOP3αis associated with the regulation of meiotic recombination in G.hybrida.

Directional-to-random transition of cell cluster migration

Efficient cell migration is crucial for the functioning of biological processes, e.g., morphogenesis, wound healing, and cancer metastasis. In this study, we monitor the migratory behavior of the 3D fibroblast clusters using live cell microscopy,and find that crowded environment affects cell migration, i.e., crowding leads to directional migration at the cluster’s periphery. The number of cell layers being stacked during seeding determines the directional-to-random transition. Intriguingly,the migratory behavior of cell clusters resembles the dispersion dynamics of clouds of passive particles, indicating that the biological process is driven by physical effects(e.g., entropy) rather than cell communication. Our findings highlight the role of intrinsic physical characteristics, such as crowding, in regulating biological behavior, and suggest new therapeutic approaches targeting at cancer metastasis.

Differences in Immune Responses between Children and Adults with COVID-19

Over 85590000 individuals have been infected with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Although there have been an increasing number of reports on coronavirus disease 2019(COVID-19),it is unclear why infected children show milder symptoms than adults.A retrospective case study was performed at two designated hospitals for COVID-19.Patients(56 children and 63 adults)with confirmed SARS-CoV-2 infection and mild pneumonia were randomly enrolled in this study.The median age of the children was 7.0 years,and 51.79%of them were boys.The median age of the adults was 57 years,and 47.62%were men.The most common symptoms were fever,cough,sputum and diarrhoea.There were no significant differences in symptoms between children and adult patients.In terms of immunological indices on admission,adult patients displayed typical leukopenia and markedly higher levels of IL-2,IL-4,and IL-6 than child patients.The elevation of IL-2,IL-4 and IL-6 in adults induced more extensive lung injury.The effective and non-aggressive immune response successfully resisted SARS-CoV-2 invasion and maintained mild symptoms in child patients.The correlation of higher IL-2,IL-4,and IL-6 with the lung injury might be evidence that preventing excessive cytokine production can avoid further lung damage in these patients.

袋型阻尼密封动力特性数值与实验研究

通过非定常动网格技术,建立了袋型阻尼密封动力特性多频椭圆涡动求解模型,在实验验证求解模型准确性的基础上,研究了袋型阻尼密封腔室轴向长度、周向挡板数量及深度对密封动力特性的影响;并对不同周向挡板数量的等腔室袋型阻尼密封的泄漏特性进行实验研究。研究发现,密封腔室轴向长度为d=4/8mm的传统袋型阻尼密封比d=10mm的等腔室袋型阻尼密封的有效阻尼Ceff约增加21.5%;随着二次腔室轴向长度从d=10mm减小到d=6mm,有效阻尼Ceff约增加14.1%,流体压缩效应更加明显,增加了腔室内的动压,有利于抑制转子涡动。等腔室袋型阻尼密封的周向档板数量对其阻尼系数有显著影响,当涡动频率大于200Hz时,挡板数从24减少到4时,有效阻尼Ceff约增加37.8%,稳定性明显提高。当袋型阻尼密封空腔深度从3mm增加到6mm时,等腔室袋型阻尼密封的交叉刚度较大、Ceff约减小51.7%,稳定性降低。

A Clinical Study:Therapeutic Effects of Repetitive Transcranial Magnetic Stimulation and Cognitive Behavioral Therapy on Cognitive Impairment in Alcohol-Dependent Patients

Objective To observe the effects of repetitive transcranial magnetic stimulation(rTMS)and cognitive behavioral therapy(CBT)on cognitive function in alcohol-dependent patients.Methods Data from 285 alcohol-dependent patients were collected from Mudanjiang Medical University and Sun Yat-sen Memorial Hospital at Sun Yat-sen University between 2019 and 2021.The patients were divided into groups depending on alcohol abstinence and non-abstinence.There were 43 patients in the alcohol consumption(AC)group.The patients in the abstinence group were randomly assigned to treatment regimens with different combinations of rTMS and CBT using the Elton system.There were 49 patients in the TB+C0 group,36 in the TB+C1 group,44 in the TL+C0 group,36 in the TL+C1 group,37 in the TR+C0 group,and 40 in the TR+C1 group.Cognitive function was assessed by using the Montreal Cognitive Assessment Scale(MoCA).Results The proportion of patients with cognitive impairment in the AC group at 24 weeks was higher than that at baseline(P<0.05),whereas the proportion of cognitive impairment in the other groups did not differ significantly over time.The percentage of patients with cognitive impairment at 24 weeks was 52.3%in the TL+C0 group and 47.2%in the TL+C1 group,which was significantly lower than that in the AC group(P<0.05).MoCA scores at different time points in the AC group were significantly higher than those in the TB+C0,TL+C0,TL+C1,TR+C0,and TR+C1 groups,respectively.MoCA scores were significantly higher at 12 weeks compared with the baseline in the TB+C0,TL+C0,TL+C1,TR+C0,and TR+C1 groups(P<0.05),and similar changes were observed at 24 weeks.The MoCA scores in the TL+C1 and TL+C0 groups were higher than those in the TR+C0 group at 12 weeks after the intervention(P<0.05).Furthermore,MoCA scores in each of the TB+C1,TL+C1,TL+C0,TR+C1,and TR+C0 groups were higher than those in the AC group at 24 weeks(P<0.05).Conclusion Alcohol consumption impairs cognitive function,as evidenced by a significantly higher proportion of cognitive impairment after 24 weeks of non-abstinence.Most of the tested treatment regimens improved cognitive function.High frequency rTMS of the left dorsolateral prefrontal cortex(DLPFC)was associated with a greater improvement in cognitive function than that of the right DLPFC in alcohol-dependent patients at 12 weeks of abstinence.There does not appear to be a therapeutic advantage of CBT for cognitive impairment in alcohol-dependent patients.Screening for impaired cognitive function should be seriously considered for patients who engage in heavy drinking,and measures should be taken to reduce the risk of dementia induced by alcohol dependence.

Novel 2D bifunctional layered rare-earth hydroxides@GO catalyst as a functional interlayer for improved liquid-solid conversion of polysulfides in lithium-sulfur batteries

The detrimental“shuttle effect”of lithium polysulfides(LiPSs)together with sluggish multi-order reaction kinetics are the main drawbacks hindering lithium-sulfur(Li-S)batteries from commercial success.Here,we first propose the implementability of layered rare-earth hydroxides(LREHs)in Li-S batteries to optimize electrochemical performance.In this work,a two-dimensional(2D)rare-earth-based composite constructed by the layered gadolinium hydroxy chloride[Gd_(2)(OH)_(5)(H_(2)O)_(n)]Cl nanoplates(LGdH NPs)and graphene oxide(GO)was designed as a sulfur immobilizer for Li-S batteries.Combining the experimental results and density functional theory(DFT)calculations,it is revealed that the LGdH@GO composite not only provides a strong anchoring of the intermediates during cycling,but also acts as an effective catalyst to accelerate the liquid-solid conversion of polysulfides.The Li-S batteries assembled by LGdH@GO modified separators delivered a superior rate performance with a specific capacity of 605.34 mAh/g at 5 C,as well as excellent cycle stability with a decay rate of 0.087%over 500 cycles at 2 C.This study provided a deep understanding of the mechanism to suppress the“shuttle effect”by the LREHs,and a guide to design effective functional interlayers for high-performance Li-S batteries with excellent electrocatalytic activity.

Genome-wide pan-GPCR cell libraries accelerate drug discovery

G protein-coupled receptors(GPCRs)are pivotal in mediating diverse physiological and pathological processes,rendering them promising targets for drug discovery.GPCRs account for about 40%of FDA-approved drugs,representing the most successful drug targets.However,only approximately 15%of the 800 human GPCRs are targeted by market drugs,leaving numerous opportunities for drug discovery among the remaining receptors.Cell expression systems play crucial roles in the GPCR drug discovery field,including novel target identification,structural and functional characterization,potential ligand screening,signal pathway elucidation,and drug safety evaluation.Here,we discuss the principles,applications,and limitations of widely used cell expression systems in GPCR-targeted drug discovery,GPCR function investigation,signal pathway characterization,and pharmacological property studies.We also propose three strategies for constructing genome-wide pan-GPCR cell libraries,which will provide a powerful platform for GPCR ligand screening,and facilitate the study of GPCR mechanisms and drug safety evaluation,ultimately accelerating the process of GPCR-targeted drug discovery.

Rational design of practical layered transition metal oxide cathode materials for sodium-ion batteries

Sodium-ion batteries (SIBs), which serve as alternatives or supplements to lithium-ion batteries, have been developed rapidly in recent years. Designing advanced high-performance layered NaxTMO_(2) cathode materials is beneficial for accelerating the commercialization of SIBs. Herein, the recent research progress on scalable synthesis methods, challenges on the path to commercialization and practical material design strategies for layered NaxTMO_(2) cathode materials is summarized. Co-precipitation method and solid-phase method are commonly used to synthesize NaxTMO_(2) on mass production and show their own advantages and disadvantages in terms of manufacturing cost, operative difficulty, sample quality and so on. To overcome drawbacks of layered NaxTMO_(2) cathode materials and meet the requirements for practical application, a detailed and deep understanding of development trends of layered NaxTMO_(2) cathode materials is also provided, including high specific energy materials, high-entropy oxides, single crystal materials, wide operation temperature materials and high air stability materials. This work can provide useful guidance in developing practical layered NaxTMO_(2) cathode materials for commercial SIBs.