核技术在农业上应用现状和展望

近二十年来,核技术应用已经融入农业科学研究和农业生产实践的各个方面,在某些领域是唯一和不可替代的技术手段。该综述全面概述了目前全世界核技术在农业主要领域应用的最新进展及其主要成就。着重介绍了核技术在动物生产和健康、食品安全及控制、植物诱变育种和遗传、水土管理及农业环境以及害虫防治等领域的应用现状和创新发展趋势。针对世界农业所面临的诸多全球性严峻挑战,作者探讨并展示了核技术在农业上的应用前景及其优先发展的战略方向。

Panoptic UAV:Panoptic Segmentation of UAV Images for Marine Environment Monitoring

UAV marine monitoring plays an essential role in marine environmental protection because of its flexibility and convenience,low cost and convenient maintenance.In marine environmental monitoring,the similarity between objects such as oil spill and sea surface,Spartina alterniflora and algae is high,and the effect of the general segmentation algorithm is poor,which brings new challenges to the segmentation of UAV marine images.Panoramic segmentation can do object detection and semantic segmentation at the same time,which can well solve the polymorphism problem of objects in UAV ocean images.Currently,there are few studies on UAV marine image recognition with panoptic segmentation.In addition,there are no publicly available panoptic segmentation datasets for UAV images.In this work,we collect and annotate UAV images to form a panoptic segmentation UAV dataset named UAV-OUC-SEG and propose a panoptic segmentation method named PanopticUAV.First,to deal with the large intraclass variability in scale,deformable convolution and CBAM attention mechanism are employed in the backbone to obtain more accurate features.Second,due to the complexity and diversity of marine images,boundary masks by the Laplacian operator equation from the ground truth are merged into feature maps to improve boundary segmentation precision.Experiments demonstrate the advantages of PanopticUAV beyond the most other advanced approaches on the UAV-OUC-SEG dataset.

Rapid inactivation of human respiratory RNA viruses by deep ultraviolet irradiation from light-emitting diodes on a high-temperatureannealed AlN/Sapphire template

Efficient and eco-friendly disinfection of air-borne human respiratory RNA viruses is pursued in both public environment and portable usage.The AlGaN-based deep ultraviolet(DUV)light-emission diode(LED)has high practical potentials because of its advantages of variable wavelength,rapid sterilization,environmental protection,and miniaturization.Therefore,whether the emission wavelength has effects on the disinfection as well as whether the device is feasible to sterilize various respiratory RNA viruses under portable conditions is crucial.Here,we fabricate AlGaN-based DUV LEDs with different wavelength on high-temperature-annealed(HTA)AlN/Sapphire templates and investigate the inactivation effects for several respiratory RNA viruses.The AlN/AlGaN superlattices are employed between the template and upper n-AlGaN to release the strong compressive stress(SCS),improving the crystal quality and interface roughness.DUV LEDs with the wavelength of 256,265,and 278 nm,corresponding to the light output power of 6.8,9.6,and 12.5 mW,are realized,among which the 256 nm-LED shows the most potent inactivation effect in human respiratory RNA viruses,including SARS-CoV-2,influenza A virus(IAV),and human parainfluenza virus(HPIV),at a similar light power density(LPD)of~0.8 mW/cm2 for 10 s.These results will contribute to the advanced DUV LED application of disinfecting viruses with high potency and broad spectrum in a portable and eco-friendly use.

A gap-free reference genome reveals structural variations associated with flowering time in rapeseed(Brassica napus)

Allopolyploid oilseed rape(Brassica napus)is an important oil crop and vegetable.However,the latest version of its reference genome,with collapsed duplications,gaps,and other issues,prevents comprehensive genomic analysis.Herein,we report a gap-free assembly of the rapeseed cv.Xiang5A genome using a combination of ONT(Oxford Nanopore Technologies)ultra-long reads,PacBio high-fidelity reads,and Hi-C datasets.It includes gap-free assemblies of all 19 chromosomes and telomere-to-telomere assemblies of eight chromosomes.Compared with previously published genomes of B.napus,our gap-free genome,with a contig N50 length of 50.70 Mb,has complete assemblies of 9 of 19 chromosomes without manual intervention,and greatly improves contiguity and completeness,thereby representing the highest quality genome assembly to date.Our results revealed that B.napus Xiang5A underwent nearly complete triplication and allotetraploidy relative to Arabidopsis thaliana.Using the gap-free assembly,we found that 917 flowering-related genes were affected by structural variation,including BnaA03.VERNALIZATION INSENSITIVE 3 and BnaC04.HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1.These genes may play crucial roles in regulating flowering time and facilitating the adaptation of Xiang5A in the Yangtze River Basin of China.This reference genome provides a valuable genetic resource for rapeseed functional genomic studies and breeding.

国产质子转移反应质谱仪的发展现状

质子转移反应质谱(Proton Transfer Reaction Mass Spectrometer,PTR-MS)是一种快速高灵敏的挥发性有机物检测技术。国产PTR-MS自2008年建成以来,已经在部分技术和应用领域达到国际先进水平。本文首先介绍了仪器原理,阐明了待测物离子化、传输、探测过程中的主要影响因素。然后展示了国产PTR-MS的产品线,主要包括质子反转移反应质谱仪、双极性质子转移反应质谱仪、呼气检测仪、船载液体进样质谱仪、车载大气走航监测质谱仪、快速色谱-质子转移反应质谱仪等,部分产品已经实现了批量生产和销售。技术发展方面,在灵敏度提升和多反应离子制备上取得了重要进展。最后介绍了国产PTR-MS在环境、医学、安全等领域的应用,比如大气污染溯源、人体呼气中疾病标志物的发掘、爆炸物快检等。同时,展望了国产PTR-MS的发展方向和应用前景。

大气挥发性有机物实时在线监测的双极性质子转移反应质谱仪研制

大气中挥发性有机物(VOCs)能参与光化学反应,导致臭氧和气溶胶等二次污染物的产生,实时精准地监测VOCs对于大气污染成因研究具有重要意义。在质子转移反应质谱(PTR-MS)研究基础上,本工作研制一套用于大气VOCs实时在线监测的双极性质子转移反应质谱仪(Dipolar proton transfer reaction mass spectrometer,DP-PTR-MS)。相比单一反应离子H_3O^+的常规PTR-MS,DP-PTR-MS中有正负3种反应离子(H_3O^+、OH^-、(CH_3)_2COH^+),可根据实际检测需要选择切换,提高定性能力,并有效扩展检测范围。其中,H_3O^+反应离子用于检测质子亲和势大于H_2O的VOCs;OH^-反应离子可与H_3O^+反应离子配合识别VOCs,还可用于检测CO_2等无机物;(CH_3)_2COH^+反应离子可在排除干扰的情况下准确检测NH_3。利用6种标准气体测定DP-PTR-MS检出限和灵敏度,结果表明,DP-PTR-MS对甲苯的检出限为7×10^(-12)(V/V),对氨气的灵敏度为126.0 cps/10^(-9)(V/V)。利用DP-PTR-MS对合肥市区大气VOCs开展连续78h实时在线监测验证实验,结果表明,DP-PTR-MS可对大气中10^(-12)(V/V)量级VOCs进行长期实时在线监测,可作为大气污染成因研究和痕量VOCs排放监测的重要工具。

质子转移反应飞行时间质谱的建立与性能研究

介绍了自主研制的质子转移反应飞行时间质谱的基本结构和性能。首先对数据采集卡甄别离子脉冲的阈值电压进行了优化,结果表明当阈值电压为0.33V时,H3^16O^+(m/z 19)与H3^18O^+(m/z 21)的离子计数比约500:1;然后考察了水团簇离子H3O^+H2O(n=0,1,2,3)的分布与漂移管约化电场的关系,结果表明,当约化电场(E/N)为139 Td(1 Td=10^-17 Vcm^2)时,团簇离子得到很好地抑制,质谱观察到的离子主要是H3O^+,其纯度可达99%以上;随后考察了质谱的分辨率,结果表明在m/z=124处,分辨率最好,达到2653;采用不同浓度的乙醇标样对仪器的线性范围和检测限性能进行了测试,结果表明该仪器的线性动态范围可达三个数量级,检测限可达3.8 ppb;最后用该质谱仪检测了实验室空气,得到了实验室空气的质谱图。自主研制的质子转移反应飞行时间质谱可实现对痕量挥发性有机物的实时在线测量,在环境、食品、医学等领域具有重要应用价值.

单细胞RNA测序技术在病毒研究中的应用

单细胞RNA测序(single-cell RNA sequencing, scRNA-seq)技术已经成为不同领域中研究细胞异质性的有效工具。在病毒研究领域中,利用该技术分析病毒和细胞的转录组,可以在单细胞水平上检测病毒感染的动态变化,了解病毒与细胞间复杂的相互作用。本文简述了scRNA-seq技术,着重介绍病毒感染宿主细胞后scRNA-seq研究的最新进展,同时也描述了细胞周期、基因表达、细胞状态等细胞异质性对病毒感染过程的影响,以及病毒变异对其本身感染过程的影响。此外,本文还分析了scRNA-seq在研究病毒–宿主互作动态变化方面具有的独特优势,及其在病毒研究领域中广阔的应用前景,为揭示病毒的感染与致病机制、抗病毒靶标的开发等提供参考。

Nonlinear instability suppression of closed-loop pilot-vehicle system with rate-limiting actuator based on anti-windup compensation

To solve the flight safety problem caused by nonlinear instabilities(category II pilot induced oscillations, PIOs) of the closed-loop pilot-vehicle system with rate-limiting actuator, the antiwindup(AW) compensation method to avoid category II PIOs is investigated. Firstly, the AW compensation method originally used for controlling input magnitude limited system is introduced, then this method is extended for controlling input rate-limiting system through a circle criterion theorem. Secondly, the establishment of the AW compensator is transformed into the solving of linear matrix inequalities. Finally, an AW compensator establishment algorithm for the closed-loop pilot-vehicle system with the rate-limiting actuator is obtained. The effectiveness of the AW compensation method to avoid category II PIOs is validated by time-domain simulations,and compared with rate-limited feedback(RLF) command rate compensation method. The results show that the AW compensation method can effectively suppress category II PIOs and maintain the nominal performance when the closed-loop pilot-vehicle system is normal. Unlike the command rate compensator which works upon system uninterruptedly, the AW compensation method affects the closed-loop pilot-vehicle system only when the rate-limiting of actuator is activated, so it is a novel PIO avoidance method.

Safety and immunogenicity of a mosaic vaccine booster against Omicron and other SARS-CoV-2 variants:a randomized phase 2 trial

An ongoing randomized,double-blind,controlled phase 2 trial was conducted to evaluate the safety and immunogenicity of a mosaic-type recombinant vaccine candidate,named NVSI-06-09,as a booster dose in subjects aged 18 years and older from the United Arab Emirates(UAE),who had administered two or three doses of inactivated vaccine BBIBP-CorV at least 6 months prior to enrollment.The participants were randomly assigned with 1:1 to receive a booster dose of NVSI-06-09 or BBIBP-CorV.The primary outcomes were immunogenicity and safety against severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Omicron variant,and the exploratory outcome was cross-immunogenicity against other circulating strains.Between May 25 and 30,2022,516 adults received booster vaccination with 260 in NVSI-06-09 group and 256 in BBIBP-CorV group.Interim results showed a similar safety profile between two booster groups,with low incidence of adverse reactions of grade 1 or 2.For immunogenicity,by day 14 post-booster,the fold rises in neutralizing antibody geometric mean titers(GMTs)from baseline elicited by NVSI-06-09 were remarkably higher than those by BBIBP-CorV against the prototype strain(19.67 vs 4.47-fold),Omicron BA.1.1(42.35 vs 3.78-fold),BA.2(25.09 vs 2.91-fold),BA.4(22.42 vs 2.69-fold),and BA.5 variants(27.06 vs 4.73-fold).Similarly,the neutralizing GMTs boosted by NVSI-06-09 against Beta and Delta variants were also 6.60-fold and 7.17-fold higher than those by BBIBP-CorV.Our findings indicated that a booster dose of NVSI-06-09 was well-tolerated and elicited broad-spectrum neutralizing responses against divergent SARS-CoV-2 variants,including Omicron and its sub-lineages.

应激颗粒:细胞调控病毒感染的重要策略

真核细胞受到热休克、氧化应激、营养缺乏或者病毒感染等外界压力的刺激下会诱导一系列的应答反应,如形成应激颗粒(stress granule,SG),从而使细胞能更好地适应环境压力。SG作为胞浆中翻译起始复合物的聚集产物,在细胞的基因表达和稳态中发挥着重要的作用。病毒感染是诱导SG形成的条件之一,病毒侵入宿主细胞后会"借用"宿主的翻译机制完成自己的生命周期,宿主为了抵抗病毒的侵略而暂停翻译形成SG。本文对SG的产生及功能,SG与病毒的相互作用以及SG与病毒诱导的先天性免疫的关系等方面进行了综述,以期为进一步研究抗病毒策略提供方向。

Aircraft nonlinear stability analysis and multidimensional stability region estimation under icing conditions

Icing is one of the crucial factors that could pose great threat to flight safety,and thus research on stability and stability region of aircraft safety under icing conditions is significant for control and flight.Nonlinear dynamical equations and models of aerodynamic coefficients of an aircraft are set up in this paper to study the stability and stability region of the aircraft under an icing condition.Firstly,the equilibrium points of the iced aircraft system are calculated and analyzed based on the theory of differential equation stability.Secondly,according to the correlation theory about equilibrium points and the stability region,this paper estimates the multidimensional stability region of the aircraft,based on which the stability regions before and after icing are compared.Finally,the results are confirmed by the time history analysis.The results can give a reference for stability analysis and envelope protection of the nonlinear system of an iced aircraft.

Immunogenicity and safety of NVSI-06-07 as a heterologous booster after priming with BBIBP-CorV:a phase 2 trial

The increased coronavirus disease 2019(COVID-19)breakthrough cases pose the need of booster vaccination.We conducted a randomised,double-blinded,controlled,phase 2 trial to assess the immunogenicity and safety of the heterologous prime-boost vaccination with an inactivated COVID-19 vaccine(BBIBP-CorV)followed by a recombinant protein-based vaccine(NVSI-06-07),using homologous boost with BBIBP-CorV as control.Three groups of healthy adults(600 individuals per group)who had completed two-dose BBIBP-CorV vaccinations 1–3 months,4–6 months and≥6 months earlier,respectively,were randomly assigned in a 1:1 ratio to receive either NVSI-06-07 or BBIBP-CorV boost.Immunogenicity assays showed that in NVSI-06-07 groups,neutralizing antibody geometric mean titers(GMTs)against the prototype SARS-CoV-2 increased by 21.01–63.85 folds on day 28 after vaccination,whereas only 4.20–16.78 folds of increases were observed in control groups.For Omicron variant,the neutralizing antibody GMT elicited by homologous boost was 37.91 on day 14,however,a significantly higher neutralizing GMT of 292.53 was induced by heterologous booster.Similar results were obtained for other SARS-CoV-2 variants of concerns(VOCs),including Alpha,Beta and Delta.Both heterologous and homologous boosters have a good safety profile.Local and systemic adverse reactions were absent,mild or moderate in most participants,and the overall safety was quite similar between two booster schemes.Our findings indicated that NVSI-06-07 is safe and immunogenic as a heterologous booster in BBIBP-CorV recipients and was immunogenically superior to the homologous booster against not only SARS-CoV-2 prototype strain but also VOCs,including Omicron.