Contemporary Asymmetric Genetic Introgression Between Two Pelophylax Species in Shanghai

Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,providing novel insights into species evolution mechanisms and conservation management in the Anthropocene.The Eastern Golden Frog(Pelophylax plancyi)and BlackSpotted Frog(P.nigromaculatus)are two sympatric anuran species with a long history of mitochondrial genome introgression in highly urbanized continental East Asia.However,there is only limited understanding of the pattern of their contemporary hybridization and factors influencing their interspecific relationship under anthropogenic disturbances.Here,interspecific hybridization between P.plancyi and P.nigromaculatus at the population level was investigated in Shanghai.All except two haplotypes obtained from both species in Shanghai were mixed together,and located in the introgression clade,implying multiple ancient mitochondrial introgression events occurred in the populations of our study area.Asymmetric genetic introgression was detected by microsatellite markers,with 0.7%of P.plancyi and 14.6%of P.nigromaculatus identified as contemporary admixed individuals.Consistent with the trend of population density,higher genetic diversity of neutral microsatellite loci was found in the more abundant P.plancyi;however,variation in mitochondrial(Cyt-b)and nuclear(POMC)genes was higher in relatively rare P.nigromaculatus.The population density of P.plancyi and number of water patches within local habitats were significantly positively correlated with both occurrences and proportions of admixed individuals in the populations of P.plancyi and P.nigromaculatus.Considering the prevalent transformation of habitats in urbanized areas,these results imply that a high population density in isolated artificially altered habitats is likely to increase interspecific hybridization.Thus,population monitoring and improvement of landscape connectivity between habitats would be needed to control the intensity of interspecific hybridization between P.plancyi and P.nigromaculatus in anthropogenic-disturbed environments.

An aqueous magnesium-ion hybrid supercapacitor operated at-50℃

The recent advances in aqueous magnesium-ion hybrid supercapacitor(MHSC)have attracted great attention as it brings together the benefits of high energy density,high power density,and synchronously addresses cost and safety issues.However,the freeze of aqueous electrolytes discourages aqueous MHSC from operating at low-temperature conditions.Here,a low-concentration aqueous solution of 4 mol L^(-1) Mg(ClO_(4))_(2) is devised for its low freezing point(-67℃)and ultra-high ionic conductivity(3.37 mS cm^(-1) at-50℃).Both physical characterizations and computational simulations revealed that the Mg(ClO_(4))_(2) can effectively disrupt the original hydrogen bond network among water molecules via transmuting the electrolyte structure,thus yielding a low freezing point.Thus,the Mg(ClO_(4))_(2) electrolytes endue aqueous MHSC with a wider temperature operation range(-50℃–25℃)and a higher energy density of 103.9 Wh kg^(-1) at 3.68 kW kg^(-1) over commonly used magnesium salts(i.e.,MgSO_(4) and Mg(NO_(3))_(2))electrolytes.Furthermore,a quasi-solid-state MHSC based on polyacrylamide-based hydrogel electrolyte holds superior low-temperature performance,excellentflexibility,and high safety.This work pioneers a convenient,cheap,and eco-friendly tactic to procure low-temperature aqueous magnesium-ion energy storage device.

The mechanism of external pressure suppressing dendrites growth in Li metal batteries

Li metal is considered an ideal anode material for application in the next-generation secondary batteries.However,the commercial application of Li metal batteries has not yet been achieved due to the safety concern caused by Li dendrites growth.Despite the fact that many recent experimental studies found that external pressure suppresses the Li dendrites growth,the mechanism of the external pressure effect on Li dendrites remains poorly understood on the atomic scale.Herein,the large-scale molecular dynamics simulations of Li dendrites growth under different external pressure were performed with a machine learning potential,which has the quantum-mechanical accuracy.The simulation results reveal that the external pressure promotes the process of Li self-healing.With the increase of external pressure,the hole defects and Li dendrites would gradually fuse and disappear.This work provides a new perspective for understanding the mechanism for the impact of external pressure on Li dendrites.

Clarification of underneath capacity loss for O3-type Ni, co free layered cathodes at high voltage for sodium ion batteries

Earth abundant O3-type NaFe_(0.5)Mn_(0.5)O_(2)layered oxide is regarded as one of the most promising cathodes for sodium ion batteries due to its low cost and high energy density.However,its poor structural stability and cycle life strongly impede the practical application.Herein,the dynamic phase evolution as well as charge compensation mechanism of O3-type NaFe_(0.5)Mn_(0.5)O_(2)cathode during sodiation/desodiation are revealed by a systemic study with operando X-ray diffraction and X-ray absorption spectroscopy,high resolution neutron powder diffraction and neutron pair distribution functions.The layered structure experiences a phase transition of O3→P3→OP2→ramsdellite during the desodiation,and a new O3’phase is observed at the end of the discharge state(1.5 V).The density functional theory(DFT)calculations and nPDF results suggest that depletion of Na^(+)ions induces the movement of Fe into Na layer resulting the formation of an inert ramsdellite phase thus causing the loss of capacity and structural integrity.Meanwhile,the operando XAS clarified the voltage regions for active Mn^(3+)/Mn^(4+)and Fe^(3+)/Fe^(4+)redox couples.This work points out the universal underneath problem for Fe-based layered oxide cathodes when cycled at high voltage and highlights the importance to suppress Fe migration regarding the design of high energy O3-type cathodes for sodium ion batteries.

超高效液相色谱-串联质谱法同时测定化妆品中29种抗过敏药物

建立了超高效液相色谱-串联质谱法同时测定化妆品中29种抗过敏药物的检测方法。样品采用乙腈超声提取,经色谱柱分离,以0.1%氨水溶液和0.1%氨水甲醇溶液梯度洗脱,采用电喷雾离子源正离子模式(ESI+)电离,多反应监测(MRM)模式检测。结果表明,29种抗过敏药物在线性范围内线性关系良好,相关系数均大于0.997;检出限为0.4~12.9 ng/g,平均回收率为80.9%~115.9%,RSD为0.3%~14.8%。应用该方法对10批样品进行筛查,共有2批检出阳性,其中1批检出了赛庚啶和赛庚啶杂质1,1批检出了西咪替丁。该方法操作简便,具有良好的选择性、灵敏度及准确度,能够用于化妆品中抗过敏药物的测定。

Switchable hidden spin polarization and negative Poisson's ratio in two-dimensional antiferroelectric wurtzite crystals

Two-dimensional(2D)antiferroelectric materials have raised great research interest over the last decade.Here,we reveal a type of 2D antiferroelectric(AFE)crystal where the AFE polarization direction can be switched by a certain degree in the 2D plane.Such 2D functional materials are realized by stacking the exfoliated wurtzite(wz)monolayers with“self-healable”nature,which host strongly coupled ferroelasticity/antiferroelectricity and benign stability.The AFE candidates,i.e.,Zn X and Cd X(X=S,Se,Te),are all semiconductors with direct bandgap atΓpoint,which harbors switchable antiferroelectricity and ferroelasticity with low transition barriers,hidden spin polarization,as well as giant in-plane negative Poisson's ratio(NPR),enabling the co-tunability of hidden spin characteristics and auxetic magnitudes via AFE switching.The 2D AFE wz crystals provide a platform to probe the interplay of 2D antiferroelectricity,ferroelasticity,NPR,and spin effects,shedding new light on the rich physics and device design in wz semiconductors.

锂离子电池正极材料中的极化子现象理论计算研究进展

作为一种高能量密度储能器件,锂离子电池不仅已经广泛应用于消费电子领域(如笔记本电脑、智能手机),而且也适合用于电动车中的动力电池。正极是锂电池最为重要的组成部分。在正极材料的研究中,当电子在空间上局域分布并与晶格耦合将形成极化子,极化子现象近些年逐渐引起人们更多关注,主要是因为其减弱电子导电性,不利于电子传导,是磷酸铁锂等正极材料电子导电性差的根本原因。极化子是一种晶格畸变束缚电子作整体运动的晶体缺陷。开展极化子现象的相关机理研究,将为设计高导电性正极材料提供理论指导,对锂离子电池电化学性能的进一步提升有着重要意义。基于第一性原理的理论计算方法已成为研究正极材料中极化子的重要研究手段,能够判断体系是否有极化子出现以及分析极化子的出现对正极材料的物理化学性能影响。本文主要从理论计算的角度出发,首先介绍了极化子的基本物理概念,其次结合我们的相关研究综述了极化子的理论计算判别方法、极化子对常见类型正极材料导电性能的影响与调控和当前研究方法的一些理论难题,最后从基础理论和实际应用两个角度对未来正极材料中的极化子研究进行展望。

UPLC-ESI-Q-TOF/MS法测定化妆品中倍他米松及其8种类似物

建立了同时分析倍他米松及其8种类似物的超高效液相色谱-高分辨质谱联用仪(UPLC-ESI-Q-TOF/MS)的定性、定量检测方法。采用小颗粒色谱柱,梯度洗脱,电喷雾离子源正离子模式(ESI+),利用TOF采集的化合物母离子推测分子组成,子离子推测结构,并借助对照品加以确证,利用质谱一级准分子离子建立含量测定方法。对建立的检测方法进行方法学验证,发现考察范围内线性关系良好,检出浓度为0.05~0.34 mg/kg,回收率为93.1%~103.7%,相对标准偏差普遍小于6%。在对10批化妆品的分析中,有5批检出激素,并首次发现了2种新的激素添加物:倍他米松17-丙酸酯、倍他米松21-丙酸酯。

Two material removal modes in chemical mechanical polishing:mechanical plowing vs.chemical bonding

With the rapid development of semiconductors,the number of materials needed to be polished sharply increases.The material properties vary significantly,posing challenges to chemical mechanical polishing(CMP).Accordingly,the study aimed to classify the material removal mechanism.Based on the CMP and atomic force microscopy results,the six representative metals can be preliminarily classified into two groups,presumably due to different material removal modes.From the tribology perspective,the first group of Cu,Co,and Ni may mainly rely on the mechanical plowing effect.After adding H_(2)O_(2),corrosion can be first enhanced and then suppressed,affecting the surface mechanical strength.Consequently,the material removal rate(MRR)and the surface roughness increase and decrease.By comparison,the second group of Ta,Ru,and Ti may primarily depend on the chemical bonding effect.Adding H_(2)O_(2)can promote oxidation,increasing interfacial chemical bonds.Therefore,the MRR increases,and the surface roughness decreases and levels off.In addition,CMP can be regulated by tuning the synergistic effect of oxidation,complexation,and dissolution for mechanical plowing,while tuning the synergistic effect of oxidation and ionic strength for chemical bonding.The findings provide mechanistic insight into the material removal mechanism in CMP.

上海地区金线侧褶蛙种群的潜在空间分布格局及其景观连通性

城市化导致的栖息地破碎和丧失是全球范围内威胁野生动物生存的重要因素。两栖动物是受城市化威胁最严重的陆生脊椎动物类群。研究城市化区域两栖动物空间分布格局,探究影响其片断化小种群间基因交流的景观连通性等问题,有助于我们深入理解城市化对野生动物种群的作用机制及造成的影响,能够为当地生物多样性保护提供理论指导。本研究以上海地区金线侧褶蛙(Pelophylaxplancyi)为研究对象,基于Landsat-8卫星影像,获取上海地区土地利用类型、归一化植被指数(normalized difference vegetation index,NDVI)、地表温度等景观、环境数据。结合野外种群调查,通过最大熵(maximum entropy,MaxEnt)模型得到金线侧褶蛙在本地区的潜在空间分布格局;基于电路理论(Circuitscape)计算各小种群间的扩散阻力距离;结合微卫星位点(simple sequence repeat,SSR)和单核苷酸多态性位点(single nucleotide polymorphism,SNP)计算各小种群间的遗传距离(FST),通过Mantel相关性检验探讨地理距离和阻力距离对各小种群间遗传分化的作用效果。结果显示:(1)金线侧褶蛙栖息地适宜性随城市化水平的增高而显著降低;(2)NDVI是影响其潜在空间分布的主要因素,金线侧褶蛙更倾向于栖息在植被覆盖度较高的区域;(3)遗传距离与地理距离之间没有显著的相关性,但随着景观扩散阻力的增大而显著增大。因此,保护和维持郊区连续栖息地以及市区仍然保留的斑块化栖息地是现阶段保护以金线侧褶蛙为代表的本土两栖动物的首要措施。而通过优化城市景观结构,加强针对不同野生动物类群的廊道建设,促进野生动物小种群间的基因交流,则是实现城市化区域野生动物多样性自维持和长期保护的有效途径。

Discovering unusual structures from exception using big data and machine learning techniques

Recently, machine learning(ML) has become a widely used technique in materials science study. Most work focuses on predicting the rule and overall trend by building a machine learning model. However,new insights are often learnt from exceptions against the overall trend. In this work, we demonstrate that how unusual structures are discovered from exceptions when machine learning is used to get the relationship between atomic and electronic structures based on big data from high-throughput calculation database. For example, after training an ML model for the relationship between atomic and electronic structures of crystals, we find AgO2 F, an unusual structure with both Ag3+and O22à, from structures whose band gap deviates much from the prediction made by our model. A further investigation on this structure might shed light into the research on anionic redox in transition metal oxides of Li-ion batteries.

Characterization of SARS-CoV-2-specific humoral immunity and its potential applications and therapeutic prospects

Coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),is an ongoing pandemic that poses a great threat to human health worldwide.As the humoral immune response plays essential roles in disease occurrence and development,understanding the dynamics and characteristics of virus-specific humoral immunity in SARS-CoV-2-infected patients is of great importance for controlling this disease.In this review,we summarize the characteristics of the humoral immune response after SARS-CoV-2 infection and further emphasize the potential applications and therapeutic prospects of SARSCoV-2-specific humoral immunity and the critical role of this immunity in vaccine development.Notably,serological antibody testing based on the humoral immune response can guide public health measures and control strategies;however,it is not recommended for population surveys in areas with very low prevalence.Existing evidence suggests that asymptomatic individuals have a weaker immune response to SARS-CoV-2 infection,whereas SARS-CoV-2-infected children have a more effective humoral immune response than adults.The correlations between antibody(especially neutralizing antibody)titers and protection against SARS-CoV-2 reinfection should be further examined.In addition,the emergence of cross-reactions among different coronavirus antigens in the development of screening technology and the risk of antibody-dependent enhancement related to SARS-CoV-2 vaccination should be given further attention.

Wavelength-Dependent Solar N_(2) Fixation into Ammonia and Nitrate in Pure Water

Solar-driven N_(2) fixation using a photocatalyst in water presents a promising alternative to the traditional Haber-Bosch process in terms of both energy efficiency and environmental concern.At present,the product of solar N_(2) fixation is either NH_(4)^(+)or NO_(3)^(-).Few reports described the simultaneous formation of ammonia(NH_(4)^(+))and nitrate(NO_(3)^(-))by a photocatalytic reaction and the related mechanism.In this work,we report a strategy to photocatalytically fix nitrogen through simultaneous reduction and oxidation to produce NH_(4)^(+)and NO_(3)^(-)byW18O49 nanowires in pure water.The underlying mechanism of wavelength-dependent N_(2) fixation in the presence of surface defects is proposed,with an emphasis on oxygen vacancies that not only facilitate the activation and dissociation of N_(2) but also improve light absorption and the separation of the photoexcited carriers.Both NH_(4)^(+)and NO_(3)^(-)can be produced in pure water under a simulated solar light and even till the wavelength reaching 730 nm.The maximum quantum efficiency reaches 9%at 365 nm.Theoretical calculation reveals that disproportionation reaction of the N_(2) molecule is more energetically favorable than either reduction or oxidation alone.It is worth noting that the molar fraction of NH_(4)^(+)in the total product(NH_(4)^(+)plus NO_(3)^(-))shows an inverted volcano shape from 365nm to 730 nm.The increased fraction of NO_(3)^(-)from 365 nm to around 427 nm results from the competition between the oxygen evolution reaction(OER)at W sites without oxygen vacancies and the N_(2) oxidation reaction(NOR)at oxygen vacancy sites,which is driven by the intrinsically delocalized photoexcited holes.From 427nm to 730 nm,NOR is energetically restricted due to its higher equilibrium potential than that of OER,accompanied by the localized photoexcited holes on oxygen vacancies.Full disproportionation of N_(2) is achieved within a range of wavelength from~427nm to~515 nm.This work presents a rational strategy to efficiently utilize the photoexcited carriers and optimize the photocatalyst for practical nitrogen fixation.

Recent advances in visible-light-driven conversion of CO_(2)by photocatalysts into fuels or value-added chemicals

The photocatalytic conversion of CO_(2)into sustainable,green fuels and value-added chemicals is believed to be an appealing method to overcome both the energy crisis and environmental problems.Numerous efforts have been dedicated to enhance the CO_(2)conversion efficiency and selectivity through developing photocatalysts and CO_(2)reduction systems in recent years.This review gives an overview of the latest progress in photocatalysts for visible-light photocatalytic CO_(2)conversion and recent research advances of heterogeneous photocatalytic CO_(2)conversion systems.Furthermore,The roles of cocatalyst and heterojunctions to increase the efficiency of charge transfer,separation and visible light excitation are discussed.Finally,the challenges and perspectives for visible-light-driven photocatalytic conversion of CO_(2)are proposed.

Breaking the energy density limit of Li NiO_(2):Li_(2)NiO_(3)or Li_(2)NiO_(2)?

The development of next-generation layered oxide cathodes for high-energy-density electrical vehicle Li-ion batteries(LIBs)is an urgent topic.The existing method is achieved by continuously increasing the Ni contents of Ni-based layered oxides,but it has been limited to LiNiO_(2).To break this limit and attain increased energy densities,a promising strategy,which involves the introduction of excess Li ions into transition metal(TM)layers to form Li-excess compounds Li_(2)MO_(3)(M is a TM cation),has attracted enormous interest recently.However,another strategy,which has been neglected in recent years,involves the insertion of an extra layer of Li ions between the TM and original Li layers to form Li_(2)MO_(2).In this study,typical reversible Li_(2)NiO_(3) and 1T-Li_(2)NiO_(2) were selected as two representative cathodes to break the limit of LiNiO_(2),thereby availing comprehensive comparison with LiNiO_(2) regarding their overall properties as cathodes from a theoretical perspective.Interestingly,dissimilar to the Ni^(3+)/Ni^(4+)monoelectron cationic redox associated with LiNiO_(2),a polaronic anionic redox reaction occurs in Li_(2)NiO_(3),while a reversible Ni^(2+)/Ni^(4+)double-electron redox reaction accompanied by insulator-metal transition occurs in Li_(2)NiO_(2).Owing to this double-electron cationic activity,Li_(2)NiO_(2) exhibits absolute advantages over the other two materials(LiNiO_(2) and Li_(2)NiO_(3))as cathodes for LIBs in terms of the capacity,energy density,electronic conductivity,and thermal stability,thus rendering it the most promising candidate for next-generation layered oxide cathodes with high energy densities to break the limit of LiNiO_(2).

Multiferroicity and giant in-plane negative Poisson’s ratio in wurtzite monolayers

Monolayers of layered materials,such as graphite and molybdenum dichalcogenides,have been the focus of materials science in the last decades.Here,we reveal benign stability and intriguing physical properties in the thinnest monolayer wurtzite(wz)semiconductors,which can be exfoliated from their bulk and stacked to reform the wz crystals.The candidate ZnX and CdX(X=S,Se,Te)monolayers possess low cleavage energy and direct bandgaps,which harbor strongly coupled ferroelectricity and ferroelasticity with low transition barriers,giant in-plane negative Poisson’s ratio,as well as giant Rashba spin splitting,enabling the co-tunability of spin splitting and auxetic magnitudes via multiferroic switching.These wz monolayers can be used as building blocks of devices structures,due to their inherent“self-healable”capacity,which offer more flexibility for semiconductor fabrication and provide a natural platform to probe the interplay of multiple physical effects,bringing light into the rich physics in tetrahedral semiconductors.

Defect-mediated Jahn-Teller effect in layered LiNiO_(2)

LiNiO_(2)(LNO)基态的晶体结构和电子结构长期以来存在着实验与理论计算不一致的争议.实验上观测到LNO是空间群为R3m的半导体并且有局部的Jahn-Teller(JT)畸变,但理论计算却表明它是处于亚稳态的金属并且没有任何的JT畸变.本文基于杂化密度泛函理论HSE06,首次模拟了与实验等同浓度(~3%)的Ni/Li反位缺陷对LNO的影响,发现缺陷能够有效调控LNO中的JT效应.在LNO中引入Ni/Li反位缺陷后,其结构发生了局部的JT畸变,并且其带隙值约为0.5 eV,这些计算结果都和实验现象非常吻合.Ni/Li反位通过粒径效应和库伦作用,既能诱发JT畸变,又能阻碍畸变之间的协同作用,避免相变到C2/m,而只产生局部的JT畸变.本文提出了一种新的策略来解释LNO基态晶体结构和电子结构长期以来的争议,对推动富镍层状材料的设计和应用具有重要意义.

Realization of humoral immunity against SARS-CoV-2 infections

The coronavirus disease 2019(COVID-19)pandemic,caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),is a major ongoing challenge to global health.After being infected by SARS-CoV-2,a specific humoral immune response may be rapidly induced in the host to restrain the viral infection via the production of neutralizing antibodies(NAbs),which are also useful for preventing reinfection[1,2].However,there is a lack of comprehensive understanding of the mechanisms underlying SARS CoV-2 specifc humoral immunity and alterations in immunoglobulin M(1gM)and G(1gG)levels in humans during viral infection.

Characterization of Specific Humoral Immunity in Asymptomatic SARS-CoV-2 Infection

The outbreak of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection in December 2019 caused a huge blow to both global public health and global economy.At the early stage of the coronavirus disease 2019(COVID-19)epidemic,asymptomatic individuals with SARS-CoV-2 infection were ignored,without appropriate identification and isolation.However,asymptomatic individuals proved to comprise a high proportion of all SARS-CoV-2-infected individuals,which greatly contributed to the rapid and wide spread of this disease.In this review,we summarize the latest advances in epidemiological characteristics,diagnostic assessment methods,factors related to the establishment of SARS-CoV-2 asymptomatic infection,as well as humoral immune features after SARS-CoV-2 infection or vaccination in asymptomatic individuals,which would contribute to effective control of ongoing COVID-19 epidemic.