Elite,transformable haploid inducers in maize

The introduction of alleles into commercial crop breeding pipelines is both time consuming and costly.Two technologies that are disrupting traditional breeding processes are doubled haploid(DH)breeding and genome editing(GE).Recently,these techniques were combined into a GE trait delivery system called HI-Edit(Haploid Inducer-Edit).In HI-Edit,the pollen of a haploid inducer line is reprogrammed to deliver GE traits to any variety,obviating recurrent selection.For HI-Edit to operate at scale,an efficient transformable HI line is needed,but most maize varieties are recalcitrant to transformation,and haploid inducers are especially difficult to transform given their aberrant reproductive behaviors.Leveraging marker assisted selection and a three-tiered testing scheme,we report the development of new Iodent and Stiff Stalk maize germplasm that are transformable,have high haploid induction rates,and exhibit a robust,genetically-dominant anthocyanin native trait that may be used for rapid haploid identification.We show that transformation of these elite‘‘HI-Edit”lines is enhanced using the BABYBOOM and WUSCHEL morphogenetic factors.Finally,we evaluate the HI-Edit performance of one of the lines against both Stiff Stalk and non-Stiff Stalk testers.The strategy and results of this study should facilitate the development of commercially scalable HI-Edit systems in diverse crops.

Photodetectors based on small-molecule organic semiconductor crystals

Small-molecule organic semiconductor crystals(SMOSCs) combine broadband light absorption(ultraviolet–visible–near infrared) with long exciton diffusion length and high charge carrier mobility. Therefore, they are promising candidates for realizing high-performance photodetectors. Here, after a brief resume of photodetector performance parameters and operation mechanisms, we review the recent advancements in application of SMOSCs as photodetectors, including photoconductors, phototransistors, and photodiodes. More importantly, the SMOSC-based photodetectors are further categorized according to their detection regions that cover a wide range from ultraviolet to near infrared. Finally, challenges and outlooks of SMOSC-based photodetectors are provided.

Perspective:Acoustic Metamaterials in Future Engineering

Acoustic metamaterials(AMMs)are a type of artificial materials that make use of appropriate structural designs and exhibit exotic properties not found in natural materials,such as negative effective material parameters(e.g.,bulk modulus,mass density,and refractive index).These interesting properties offer novel means for sound manipulation and thus have drawn a great deal of attention.Over the past two decades,tremendous progress has been made in the fundamental research of AMMs,which has not only promoted the development of modern acoustics but also shown the potential of AMMs for engineering applications.Here,we review recent developments in AMMs with a focus on their future engineering,especially in the most promising fields of sound absorption/isolation,acoustic imaging,cloaking,and so on,furthermore,we outline the opportunities and challenges they are encountering.

Development of a psychosocial functioning questionnaire for patients with major depressive disorder

Background The importance of psychosocial functioning in the assessment,diagnosis and treatment of major depressive disorder(MDD)is widely recognised.However,there is a lack of effective scales to assess psychosocial functioning in patients with MDD.Aims To develop a professional questionnaire to evaluate the psychosocial functioning of patients with MDD.Methods Using a literature review,an open-ended questionnaire survey,and patient interviews,a theoretical model of psychosocial functioning was constructed,and an initial questionnaire was formed which included four dimensions.After two rounds of testing,using items analysis and exploratory factor analysis,a finalized questionnaire was created.There were 460 patients with MDD selected from six psychiatric hospitals for formal testing using a convenience sampling method.Forty patients were randomly selected and retested one week later to evaluate the test-retest reliability of the scale.The Patient Health Questionnaire-9(PHQ-9),Short Form of Quality of Life Enjoyment and Satisfaction Questionnaire(Q-LES Q SF),Sheehan Disability Scale(SDS),and Dysfunctional Attitudes Scale(DAS)provided major standards to check the criterion validity of this questionnaire.Correlation analysis,confirmatory factor analysis,and internal consistency reliability testing were used to examine other psychometric characteristics of the finalized questionnaire.Results The Psychosocial Functioning Questionnaire(PFQ)for patients with MDD included three dimensions:psychological cognitive functioning,subjective well-being,and social functioning,with a total of 18 items.The overall internal consistency reliability of the questionnaire was 0.957,and the test-retest reliability was 0.840.Confirmatory factor analysis showed that the model fitted well:Goodness of Fit Index(GFI)=0.888;Root Mean SquareError of Approximation(RMSEA)=0.085.The total score of PFQ was significantly correlated with the total score of PHQ-9,DAS,SDS and Q-LES Q SF(|r|=0.599-0.870,p<0.001).Conclusions The Psychosocial Functioning Questionnaire has good reliability and validity.It can be used to measure the psychosocial functioning of patients with MDD.

Controlled Growth of Large-Area Aligned Single-Crystalline Organic Nanoribbon Arrays for Transistors and Light-Emitting Diodes Driving

Organic field-effect transistors(OFETs) based on organic micro-/nanocrystals have been widely reported with charge carrier mobility exceeding 1.0 cm^2V^(-1)s^(-1), demonstrating great potential for high-performance, low-cost organic electronic applications. However, fabrication of large-area organic micro-/nanocrystal arrays with consistent crystal growth direction has posed a significant technical challenge. Here, we describe a solution-processed dip-coating technique to grow large-area, aligned 9,10-bis(phenylethynyl) anthracene(BPEA) and 6,13-bis(triisopropylsilylethynyl) pentacene(TIPSPEN) single-crystalline nanoribbon arrays. The method is scalable to a 5 9 10 cm^2 wafer substrate, with around 60% of the wafer surface covered by aligned crystals. The quality of crystals can be easily controlled by tuning the dip-coating speed. Furthermore, OFETs based on well-aligned BPEA and TIPS-PEN single-crystalline nanoribbons were constructed.By optimizing channel lengths and using appropriate metallic electrodes, the BPEA and TIPS-PEN-based OFETs showed hole mobility exceeding 2.0 cm^2V^(-1)s^(-1)(average mobility 1.2 cm^2V^(-1)s^(-1)) and 3.0 cm^2V^(-1)s^(-1)(average mobility2.0 cm^2V^(-1)s^(-1)), respectively. They both have a high on/off ratio(I_(on)/I_(off))>10~9. The performance can well satisfy the requirements for light-emitting diodes driving.

聚甲基苄基二烯丙基氯化铵的制备及脱色性能

通过水溶液聚合法,采用引发剂一次性加入三阶段升温工艺,以甲基苄基二烯丙基氯化铵(DAMBAC)为单体,偶氮二异丁脒盐酸盐(V-50)为引发剂,乙二胺四乙酸四钠盐(Na4EDTA)为金属离子络合剂,对聚甲基苄基二烯丙基氯化铵(PDAMBAC)制备工艺条件采用响应曲面优化法(RSM),得到聚合物最佳制备条件为:w(DAMBAC)=82.5%,m(V-50)∶m(DAMBAC)=3.03%,m(Na4EDTA)∶m(DAMBAC)=0.0147%,T1=61.8℃,T2=70.6℃和T3=85.0℃,各阶段均反应3 h。在实验范围内,各因素的影响顺序分别为T1>T2>T3、w(DAMBAC)>m(V-50)∶m(DAMBAC)>m(Na4EDTA)∶m(DAMBAC),得到聚合物重均相对分子质量(Mw)最高值为7.86×104,单体转化率(Conv.)为90.85%。模拟活性染料废水脱色性能对比实验表明,以脱色率为考察指标,该聚合物对活性染料模拟废水的脱色效果明显优于传统的二烯丙基季铵盐均聚物--聚二甲基二烯丙基氯化铵,PDAMBAC对3种活性染料的脱色率均达到了96.00%以上,最佳投加量条件下对C.I.活性红3BF、C.I.活性蓝KN-R和C.I.活性黄3RF染料的脱色率分别为96.01%、97.21%和99.70%,分别比PDMDAAC的脱色率高9.14%、56.64%和10.42%。

Short review on liquid membrane technology and their applications in biochemical engineering

As a branch of membrane separation technology,liquid membrane has attracted great attention and expanded investigations in biological chemical engineering,with life and health concern in ecosystems.Composed of membrane solvent and mobile carrier,liquid membrane was acquired of function,performing the facilitated mass transfer across the diffusive solvent,so as for the separation and delivery achievement with efficacy.In this review,two types of liquid membrane are mainly focused,respectively on supported liquid membrane(SLM)of membrane solvent supporter in necessity,and on emulsion liquid membrane(ELM)of the required interfacial stabilizers and homogenization.Accordingly,the transfer mechanism,compositions,structure and features of SLM and ELM are introduced respectively.Moreover,the current investigations of liquid membrane have been discussed,focusing on the improvements of efficacy and stability in separation&detection,encapsulation and delivery,so as to scale up the favorable and efficient application with bio-life concern.Prospectively,this review could provide comprehensive insight into the bio-applications of liquid membrane,and guidelines for the further investigations on the efficacy and long-term applicable stability,in order to realize the industrialization.

Moraine-dammed glacial lake changes during the recent 40 years in the Poiqu River Basin,Himalayas

Glacier retreat is not only a symbol of temperature and precipitation change, but a dominating factor of glacial lake changes in alpine regions, which are of wide concern for high risk of potential outburst floods. Of all types of glacial lakes, moraine-dammed lakes may be the most dangerous to local residents in mountain regions. Thus, we monitored the dy- namics of 12 moraine-dammed glacial lakes from 1974 to 2014 in the Poiqu River Basin of central west Himalayas, as well as their associated glaciers with a combination of remote sensing, topographic maps and digital elevation models （DEMs）. Our results indicate that all monitored moraine-dammed glacial lakes have expanded by 7.46 km2 in total while the glaciers retreated by a total of 15.29 km2 correspondingly. Meteorological analysis indicates a warming and drying trend in the Nyalam region from 1974 to 2014, which accelerated glacier retreat and then augmented the supply of moraine-dammed glacial lakes from glacier melt. Lake volume and water depth changed from 1974 to 2014 which indicates that lakes Kangxico, Galongco, and Youmojanco have a high potential for outburst floods and in urgent need for continuous moni- toring or artificial excavation to release water due to the quick increase in water depths and storage capacities. Lakes Jialongco and Cirenmaco, with outburst floods in 1981 and 2002, have a high potential risk for outburst floods because of rapid lake growth and steep slope gradients surrounding them.

Combination of multi-focus Raman spectroscopy and compressive sensing for parallel monitoring of single-cell dynamics

To overcome the low efficiency of conventional confocal Raman spectroscopy,many efforts have been devoted to parallelizing the Raman excitation and acquisition,in which the scattering from multiple foci is projected onto different locations on a spectrometer's CCD,along either its vertical,horizontal dimension,or even both.While the latter projection scheme relieves the limitation on the row numbers of the CCD,the spectra of multiple foci are recorded in one spectral channel,resulting in spectral overlapping.Here,we developed a method under a com-pressive sensing framework to demultiplex the superimposed spectra of multiple cells during their dynamic processes.Unlike the previous methods which ignore the information connection be-tween the spectra of the cells recorded at different time,the proposed method utilizes a prior that a cell's spectra acquired at different time have the same sparsity structure in their principal components.Rather than independently demultiplexing the mixed spectra at the individual time intervals,the method demultiplexes the whole spectral sequence acquired continuously during the dynamic process.By penalizing the sparsity combined from all time intervals,the collaborative optimization of the inversion problem gave more accurate recovery results.The performances of the method were substantiated by a 1D Raman tweezers array,which monitored the germination of multiple bacterial spores.The method can be extended to the monitoring of many living cells randomly scattering on a coverslip,and has a potential to improve the throughput by a few orders.

Development of contingent valuation method in evaluating non-market values of resources and environment in China

The contingent valuation method （CVM） is one of the main methods for evaluating non-market values of resources. It originated in the United States and was introduced into China during the 1980s and 1990s. However, application of CVM in China is highly controversial based on three primary aspects： （I） the appropriate guidelines for CVM; （2） the elicitation techniques for willingness to pay （WTP）; and （3） reliability and validity testing of CVM. The major objectives of this paper are to i^eview the recem devel- opments pertaining to guidelines, elicitation techniques, and reliability and validity testing for application of CVM, and to summa- rize the limitations of and measures for improving application of CVM in China. The applicability of CVM in China is discussed to enhance the future development of CVM in China.

有机电化学晶体管及其在生物电子学领域的应用进展

有机电化学晶体管(organic electrochemical transistor,OECT)具有高跨导、低工作电压和高灵敏度等特点,在逻辑电路、传感器件、健康检测和仿生电子等领域显示出广泛的应用潜力.OECT器件采用独特的液态电解液结构,赋予其优异的水介质稳定性和生物兼容性,能够将微弱的离子和生物信号放大并转换为电学信号输出,因此在生物电子学领域具有内在的应用优势.本文综述了近年来OECT器件在生物电子学领域的研究进展与发展现状,从OECT器件的结构和工作原理出发,重点介绍了OECT技术在生物生理信号监测、生物化学传感和仿生神经形态方面的应用进展,最后讨论了OECT技术在生物电子学领域中仍存在的关键挑战和未来发展方向.

Data collection of wireless sensor network based on trajectory optimization of laser-charged UAV

Unmanned Aerial Vehicle(UAV)can be used as wireless aerial mobile base station for collecting data from sensors in UAV-based Wireless Sensor Networks(WSNs),which is crucial for providing seamless services and improving the performance in the next generation wireless networks.However,since the UAV are powered by batteries with limited energy capacity,the UAV cannot complete data collection tasks of all sensors without energy replenishment when a large number of sensors are deployed over large monitoring areas.To overcome this problem,we study the Real-time Data Collection with Lasercharging UAV(RDCL)problem,where the UAV is utilized to collect data from a specified WSN and is recharged using Laser Beam Directors(LBDs).This problem aims to collect all sensory data from the WSN and transport it to the base station by optimizing the flight trajectory of UAV such that realtime data performance is ensured It has been proven that the RDCL problem is NP-hard.To address this,we initially focus on studying two sub-problems,the Trajectory Optimization of UAV for Data Collection(TODC)problem and the Charging Trajectory Optimization of UAV(CTO)problem,whose objectives are to find the optimal flight plans of UAV in the data collection areas and charging areas,respectively.Then we propose an approximation algorithm to solve each of them with the constant factor.Subsequently,we present an approximation algorithm that utilizes the solutions obtained from TODC and CTO problems to address the RDCL problem.Finally,the proposed algorithm is verified by extensive simulations.

UAV-Assisted Multi-Object Computing Offloading for Blockchain-Enabled Vehicle-to-Everything Systems

This paper investigates an unmanned aerial vehicle(UAV)-assisted multi-object offloading scheme for blockchain-enabled Vehicle-to-Everything(V2X)systems.Due to the presence of an eavesdropper(Eve),the system’s com-munication links may be insecure.This paper proposes deploying an intelligent reflecting surface(IRS)on the UAV to enhance the communication performance of mobile vehicles,improve system flexibility,and alleviate eavesdropping on communication links.The links for uploading task data from vehicles to a base station(BS)are protected by IRS-assisted physical layer security(PLS).Upon receiving task data,the computing resources provided by the edge computing servers(MEC)are allocated to vehicles for task execution.Existing blockchain-based computation offloading schemes typically focus on improving network performance,such as minimizing energy consumption or latency,while neglecting the Gas fees for computation offloading and the costs required for MEC computation,leading to an imbalance between service fees and resource allocation.This paper uses a utility-oriented computation offloading scheme to balance costs and resources.This paper proposes alternating phase optimization and power optimization to optimize the energy consumption,latency,and communication secrecy rate,thereby maximizing the weighted total utility of the system.Simulation results demonstrate a notable enhancement in the weighted total system utility and resource utilization,thereby corroborating the viability of our approach for practical applications.

Secure Transmission Scheme for Blocks in Blockchain-Based Unmanned Aerial Vehicle Communication Systems

In blockchain-based unmanned aerial vehicle(UAV)communication systems,the length of a block affects the performance of the blockchain.The transmission performance of blocks in the form of finite character segments is also affected by the block length.Therefore,it is crucial to balance the transmission performance and blockchain performance of blockchain communication systems,especially in wireless environments involving UAVs.This paper investigates a secure transmission scheme for blocks in blockchain-based UAV communication systems to prevent the information contained in blocks from being completely eavesdropped during transmission.In our scheme,using a friendly jamming UAV to emit jamming signals diminishes the quality of the eavesdropping channel,thus enhancing the communication security performance of the source UAV.Under the constraints of maneuverability and transmission power of the UAV,the joint design of UAV trajectories,transmission power,and block length are proposed to maximize the average minimum secrecy rate(AMSR).Since the optimization problem is non-convex and difficult to solve directly,we first decompose the optimization problem into subproblems of trajectory optimization,transmission power optimization,and block length optimization.Then,based on firstorder approximation techniques,these subproblems are reformulated as convex optimization problems.Finally,we utilize an alternating iteration algorithm based on the successive convex approximation(SCA)technique to solve these subproblems iteratively.The simulation results demonstrate that our proposed scheme can achieve secure transmission for blocks while maintaining the performance of the blockchain.

Liquid-liquid interface‐assisted growth of two‐dimensional organic semiconductor single crystals:Mechanisms,properties,and applications

Two‐dimensional organic semiconductor single crystals(2D OSSCs)represent the promising candidates for the construction of high‐performance electronic and optoelectronic devices due to their ultrathin thicknesses,free of grain boundaries,and long‐range ordered molecular structures.In recent years,substantial efforts have been devoted to the fabrication of the large‐sized and layer‐controlled 2D OSSCs at the liquid‐liquid interface.This unique interface could act as the molecular flat and defect‐free substrate for regulating the nucleation and growth processes and enabling the formation of large‐sized ultrathin 2D OSSCs.Therefore,this review focuses on the liquid-liquid interface‐assisted growth methods for the controllable preparation of 2D OSSCs,with a particular emphasis on the advantages and limitations of the corresponding methods.Furthermore,the typical methods employed to control the crystal sizes,morphologies,structures,and orientations of 2D OSSCs at the liquid-liquid interface are discussed in detail.Then,the recent progresses on the 2D OSSCs‐based optoelectronic devices,such as organic field‐effect transistors,ambipolar transistors,and phototransistors are highlighted.Finally,the key challenges and further outlook are proposed in order to promote the future development of the 2D OSSCs in the field of the next‐generation organic optoelectronic devices.

Characterization of the receptor-binding domain(RBD)of 2019 novel coronavirus:implication for development of RBD protein as a viral attachment inhibitor and vaccine

The outbreak of Coronavirus Disease 2019(COVID-19)has posed a serious threat to global public health,calling for the development of safe and effective prophylactics and therapeutics against infection of its causative agent,severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),also known as 2019 novel coronavirus(2019-nCoV).The CoV spike(S)protein plays the most important roles in viral attachment,fusion and entry,and serves as a target for development of antibodies,entry inhibitors and vaccines.Here,we identified the receptor-binding domain(RBD)in SARS-CoV-2 S protein and found that the RBD protein bound strongly to human and bat angiotensin-converting enzyme 2(ACE2)receptors.SARS-CoV-2 RBD exhibited significantly higher binding affinity to ACE2 receptor than SARS-CoV RBD and could block the binding and,hence,attachment of SARS-CoV-2 RBD and SARS-CoV RBD to ACE2-expressing cells,thus inhibiting their infection to host cells.SARS-CoV RBD-specific antibodies could crossreact with SARS-CoV-2 RBD protein,and SARS-CoV RBD-induced antisera could cross-neutralize SARS-CoV-2,suggesting the potential to develop SARS-CoV RBD-based vaccines for prevention of SARS-CoV-2 and SARS-CoV infection.

External-force-driven solution epitaxy of large-area 2D organic single crystals for high-performance field-effect transistors

Growth of two-dimensional(2D)organic single crystals(2DOSCs)on water surface has attracted increasing attention,because it can serve as a molecularly flat and defect-free substrate.However,large-area growth of 2DOSCs with controllable crystal orientation on water surface remains a key challenge.Herein,we develop a simple method,i.e.external-force-driven solution epitaxy(EFDSE),for the large-area growth of 2DOSCs at air/water interface.Using 2,7-didecylbenzothienobenzothiophene(C1o-BTBT)as an example,high-quality 2D C10-BTBT crystals on centimeter scale are generated by directionally controlling the spreading of organic solution on water surface with external force.Benefiting from the controllable crystal orientation with optimal charge transport,the corresponding 2DOSC-based organic field-effect transistors(OFETs)exhibit a high carrier mobility of 13.5 cm^2·V^-1·s^-1(effective mobility=5.4 cm^2·V^-1·s^-1 according to a reliability factor of 40%),which represents the best result achieved for water-surface-assembled 2DOSC based OFETs.Furthermore,by transterring the C1o-BTBT 2DOSCs to flexible substrates,devices with excellent bending stability are achieved.It is anticipated that our method will provide new insight into the controllable growth of large-area 2DOSCs for high-performance organic devices.

Few-layer fbrmamidinium lead bromide nanoplatelets for ultrapuregreen and high-efficiency light-emitting diodes

Formamidinium lead bromide perovskite(FAPbBr3)nanocrystals have attracted increasing attention due to their greener photoluminescence(PL)and higher thermal stability in comparison to more popular methylammonium lead bromide perovskite(MAPbBr3).Here we proposed a-facile and highly reproducible room-temperature method for the preparation of fewlayer(1-4)two-dimensional(2D)FAPbBr3 nanoplatelets(NPs)with ultrapure green PL at 532 nm and high photoluminescence quantum yield(PLQY)of 88%.High-efficiency ultrapure green light-emitting diodes(LEDs)based on the few-layer 2D FAPbBr3 NPs were further demonstrated.The LEDs showed a maximum current efficiency(CE)of 15.31cd/A and an external quantum efficiency(EQE)of 3.53%,which are significantly better than the FAPbBr3 polycrystalline film-based LEDs reported so far.Significantly,the 2D FAPbBr3 NPs-based LEDs exhibited an ultrapure-green color emission that could cover 97%of the Recommendation 2020(Rec.2020)color standard and 114%of the national television system committee(NTSC)standard in the CIE 1931 color space.Moreover,the devices possessed a much better stability than the MAPbBr3 nanocrystals-based LEDs in air;the half lifetime T50 of our devices was about 5 times Ion ger than that of MAPbBr3 nan ocrystals-based LEDs.This work demonstrates the great potential of FAPbBr3 NPs in light-emitting devices for future ultrahigh-resolution displays.

Aerosol-assisted submicronγ-Fe2O3/C spheres as a promising heterogeneous Fenton-like catalyst for soil and groundwater remediation:Transport,adsorption and catalytic ability

This research reports a novel heterogeneous Fenton-like catalyst which could freely move through the model sediments and easily seize the pollutants in addition to efficiently catalyze H2O2,well suitable for soil and groundwater remediation.Herein,submicron y-Fe2O3/C spheres were synthesized through a facile one-step aerosol-based process.In a series of column tests,these spheres exhibit better transport ability due to their optimal size,conforming to the prediction by the Tufenkji-Elimelech filtration theo ry.Meanwhile,y-Fe2O3/C spheres could act as a strong adsorbent for organic pollutants owing to the presence of carbon,thereby providing a driving force to gather contaminants into their vicinity and facilitating the reaction.In addition,immobilization of y-Fe2O3 nanoparticles into carbon spheres protects iron oxides from aggregation,and thus retains the number of active sites for catalytic decomposition of H2O2.Hence,the system containing the as-prepared y-Fe2O3/C spheres and H2O2 shows the high removal efficiency and degradation efficiency in the remediation of recalcitrant organic contaminants such as methylene blue and sulfamethoxazole.

Neutralizing antibodies for the prevention and treatment of COVID-19

Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)initiates the infection process by binding to the viral cellular receptor angiotensin-converting enzyme 2 through the receptor-binding domain(RBD)in the S1 subunit of the viral spike(S)protein.This event is followed by virus–cell membrane fusion mediated by the S2 subunit,which allows virus entry into the host cell.Therefore,the SARS-CoV-2 S protein is a key therapeutic target,and prevention and treatment of coronavirus disease 2019(COVID-19)have focused on the development of neutralizing monoclonal antibodies(nAbs)that target this protein.In this review,we summarize the nAbs targeting SARS-CoV-2 proteins that have been developed to date,with a focus on the N-terminal domain and RBD of the S protein.We also describe the roles that binding affinity,neutralizing activity,and protection provided by these nAbs play in the prevention and treatment of COVID-19 and discuss the potential to improve nAb efficiency against multiple SARSCoV-2 variants.This review provides important information for the development of effective nAbs with broad-spectrum activity against current and future SARS-CoV-2 strains.