结构参数对领结型纳米孔等离子体光镊共振效应的影响

等离子体光镊可以将光场能量限制在纳米级的体积内,从而产生较大的梯度力对粒子进行捕获和操纵。使用时域有限差分(FDTD)方法对金膜上的领结型纳米孔进行数值分析,结果表明,在波长为400~2 000 nm范围内存在两种模式的共振,分别为Fabry-Pérot共振和等离子体共振。Fabry-Pérot共振对金膜厚度比较敏感,随着金膜厚度增加,共振峰发生90 nm的红移;而等离子体共振峰随着孔径和孔间距的增加向波长更大的方向偏移;通过模拟粒子捕获,发现与其他材料的粒子相比,金粒子会导致等离子体共振峰发生更大的偏移,且随着粒子从结构外运动至结构底部,共振峰会持续发生红移。本研究对实际应用中纳米结构的制备具有参考价值,且在单分子操纵、生物传感等方面具有重要意义。

非线性Benjamin-Bona-Mahony-Burgers方程的非协调有限元超收敛分析

文章研究了二维非线性Benjamin-Bona-Mahony-Burgers(BBMB)方程的非协调有限元方法。利用非协调EQ^(rot)_(1)元相容误差比插值误差高一阶的特殊性质,给出了非线性BBMB方程在半离散以及向后Euler全离散格式下的超逼近和整体超收敛结果。最后,通过数值试验验证了理论分析的正确性和方法的有效性。

A novel pathogen Fusarium cuneirostrum causing common bean(Phaseolus vulgaris)root rot in China

Several fungal pathogens cause root rot of common bean,among which Fusarium spp.are the most common pathogens causing Fusarium root rot(FRR)worldwide.FRR has been becoming an increasingly severe disease of common bean in China,but the species of Fusarium spp.have remained unclear.Thus,this study was performed to identify the pathogen causing common bean root rot in Liangcheng County,Inner Mongolia,China.Nineteen Fusarium-like isolates were obtained after pathogen isolation and purification.The pathogenicity test indicated that eight isolates caused severe disease symptoms on common bean,while 11 other isolates were not pathogenic.The eight pathogenic isolates,FCL1–FCL8,were identified as Fusarium cuneirostrum by morphological characterization and phylogenetic analysis using partial sequences of EF-1α,ITS,28S,and IGS regions.Host range test showed that the representative F.cuneirostrum isolate FCL3 was also pathogenic to mung bean,while not pathogenic to adzuki bean,chickpea,cowpea,faba bean,pea,and soybean.Moreover,50 common bean and 50 mung bean cultivars were screened for resistance to FRR,and seven highly resistant or resistant cultivars of common bean were identified,while no resistant cultivars of mung bean were screened.This study revealed that F.cuneirostrum was one of common bean FRR pathogens in Inner Mongolia and it could induce mung bean root rot as well.To our knowledge,this is the first report of F.cuneirostrum causing FRR of common bean in China.

Controllable optical bistability in a Fabry-Pérot cavity with a nonlinear three-dimensional Dirac semimetal

Optical bistability(OB)is capable of rapidly and reversibly transforming a parameter of an optical signal from one state to another,and homologous nonlinear optical bistable devices are core components of high-speed all-optical communication and all-optical networks.In this paper,we theoretically investigated the controllable OB from a Fabry-Pérot(FP)cavity with a nonlinear three-dimensional Dirac semimetal(3D DSM)in the terahertz band.The OB stems from the third-order nonlinear bulk conductivity of the 3D DSM and the resonance mode has a positive effect on the generation of OB.This FP cavity structure is able to tune the OB because the transmittance and the reflectance can be modulated by the Fermi energy of the 3D DSM.We believe that this FP cavity configuration could provide a reference concept for realizing tunable bistable devices.

Genome-wide association mapping and genomic prediction of stalk rot in two mid-altitude tropical maize populations

Maize stalk rot reduces grain yield and quality.Information about the genetics of resistance to maize stalk rot could help breeders design effective breeding strategies for the trait.Genomic prediction may be a more effective breeding strategy for stalk-rot resistance than marker-assisted selection.We performed a genome-wide association study(GWAS)and genomic prediction of resistance in testcross hybrids of 677 inbred lines from the Tuxpe?o and non-Tuxpe?o heterotic pools grown in three environments and genotyped with 200,681 single-nucleotide polymorphisms(SNPs).Eighteen SNPs associated with stalk rot shared genomic regions with gene families previously associated with plant biotic and abiotic responses.More favorable SNP haplotypes traced to tropical than to temperate progenitors of the inbred lines.Incorporating genotype-by-environment(G×E)interaction increased genomic prediction accuracy.

Non-volatile dynamically switchable color display via chalcogenide stepwise cavity resonators

High-resolution multi-color printing relies upon pixelated optical nanostructures,which is crucial to promote color display by producing nonbleaching colors,yet requires simplicity in fabrication and dynamic switching.Antimony trisulfide(Sb_(2)S_(3))is a newly rising chalcogenide material that possesses prompt and significant transition of its optical characteristics in the visible region between amorphous and crystalline phases,which holds the key to color-varying devices.Herein,we proposed a dynamically switchable color printing method using Sb_(2)S_(3)-based stepwise pixelated Fabry-Pérot(FP)cavities with various cavity lengths.The device was fabricated by employing a direct laser patterning that is a less timeconsuming,more approachable,and low-cost technique.As switching the state of Sb_(2)S_(3) between amorphous and crystalline,the multi-color of stepwise pixelated FP cavities can be actively changed.The color variation is due to the profound change in the refractive index of Sb_(2)S_(3) over the visible spectrum during its phase transition.Moreover,we directly fabricated sub-50 nm nano-grating on ultrathin Sb_(2)S_(3) laminate via microsphere 800-nm femtosecond laser irradiation in far field.The minimum feature size can be further decreased down to~45 nm(λ/17)by varying the thickness of Sb_(2)S_(3) film.Ultrafast switchable Sb_(2)S_(3) photonic devices can take one step toward the next generation of inkless erasable papers or displays and enable information encryption,camouflaging surfaces,anticounterfeiting,etc.Importantly,our work explores the prospects of rapid and rewritable fabrication of periodic structures with nano-scale resolution and can serve as a guideline for further development of chalcogenide-based photonics components.

Effective transmittance of Fabry–Perot cavity under non-parallel beam incidence

The Fabry–Perot(FP) resonant cavity is widely used in laser and spectroscopic measurements due to its unique interference transfer function(ITF). In the ideal case of parallel incident light, the ITF of the FP resonant cavity can be expressed by the Airy function. However, in reality, it is difficult to achieve perfect parallelism with collimated beams. In this article, a theoretical model is established for non-parallel light incidence, which assumes that the non-parallel incident light is a cone-shaped beam, and the cone angle is used to quantify the non-parallelism of the beam. The transmittance function of the FP resonant cavity under non-parallel light incidence is derived. The accuracy of the model is experimentally verified. Based on this model, the effects of divergence angle, tilt angle and FP cavity parameters(reflectivity, cavity length)on the ITF are studied. The reasons for the decrease in peak value, broadening and asymmetry of the interference peak under non-parallel light incidence are explained. It is suggested that a fine balance between the interference peak and the collimation effect of the incident light should be considered in the design and application of FP resonant cavities, especially for tilted applications such as angle-scanned spectroscopy. The research results of this article have certain significance for the design and application of FP resonant cavities.

BBM-Burgers方程的非协调有限元方法的超收敛分析

研究Benjamin-Bona-Mahony-Burgers(BBM-Burgers)方程的非协调EQ_(1)^(rot)元的线性化BDF格式下的超收敛性质。通过使用数学归纳法来处理非线性项,并利用该单元已有的高精度结果及插值后处理技术,得到了在对空间剖分尺度和时间步长无网格比约束的前提下,关于离散H^(1)-模意义下具有O(h^(2)+τ^(2))阶的超逼近和超收敛结果。最后,通过给出数值算例验证了理论分析的正确性。

New Rotative Radiofrequency Technology: A Multicenter Retrospective Study on Efficacy and Safety

Background: Non-ablative radiofrequency (RF) technology is widely used for the treatment of signs of aging, skin laxity, localized fat and cellulite. However, many RF devices suffer from technical limitations that make the results highly dependent on the user’s experience or clinical limitations that compromise safety, efficacy and comfort. Objective: To evaluate the efficacy and safety of a novel semi-automatic non-ablative RF device for skin tightening, body shaping and cellulite reduction. Materials and methods: A retrospective multicenter study was performed using a novel rotative RF device with temperature and impedance control (Sculpt&Shape®, Sinclair, Spain). 58 subjects underwent a minimum of 4 treatments every 1-2 weeks. A total of 120 treatments (56.7% body and 43.3% facial) and 1034 sessions were performed. Efficacy was evaluated by 3 researchers using the Global Aesthetic Improvement Scale (GAIS) and anthropometric measurements were collected. Subject and practitioner satisfaction were recorded. Safety was evaluated by analyzing the perception of pain during the treatment and the side and adverse effects immediately after treatment and over the next 48 hours. Results: Between 25% and 50% improvement was achieved according to the GAIS. Statistically significant (p < 0.01) abdominal fold reduction of 5.1 mm and circumference reduction of 32.0 mm, 16.4 mm and 13.9 mm were recorded for the abdomen, legs and arms, respectively. 77.5% of subjects and 94.9% of practitioners were either satisfied or very satisfied. Minor adverse effects were found in 0.97% of the sessions. Conclusion: This novel semi-automatic rotative RF device has been found to provide treatments that are effective, safe and comfortable for both practitioners and subjects. .

Sine-Gordon方程二重网格方法的高精度分析

讨论了Sine-Gordon方程的二重网格有限元方法,建立了EQ_(1)^(rot)非协调元全离散逼近格式.直接利用EQ_(1)^(rot)元的插值算子和该元的性质,并对非线性项进行线性化处理,导出了能量模意义下的超逼近结果.更进一步利用插值后处理技术得到整体超收敛结果.

基于多层F-P谐振腔的石墨烯吸波体设计

为了研究当单层石墨烯位于多层Fabry-Pérot(F-P)谐振腔中时,系统近全吸波模式与多层F-P谐振腔数目之间的关系,同时提高系统对吸波模式的调控能力,采用严格耦合波分析法,对石墨烯多层F-P谐振腔系统的吸波响应进行了研究,分析了临界耦合条件下双层和3层F-P谐振腔结构的光谱响应特征。结果表明,双层和3层F-P谐振腔可调谐近全吸波体,分别形成了两个99%以上和3个96%以上的近全吸波模式;通过对石墨烯掺杂可以实现对3层F-P谐振腔系统吸波特性的调节,通过改变3层谐振腔的结构可以控制系统吸收模式的数量和相对位置。该研究为可调近全吸波系统引入更丰富的吸波线型。

Extracellular and intracellular infection of Botryosphaeria dothidea and resistance mechanism in apple cells

Apple ring rot,which is caused by Botryosphaeria dothidea,severely affects apple production.The mechanisms employed in apple cells against B.dothidea remain unknown.In this research,the pathogen infection mode and the relationship between cell death and disease resistance in‘Fuji’/B.dothidea interaction pathosystem were investigated.By using transmission electron microscopy(TEM),our research showed that the pathogen infects apple cells both intracellularly and extracellularly.However,compared with that in immature fruit,the incidence of hyphae in the interior of mature apple fruit cells increased dramatically,suggesting that cell wall-mediated penetration resistance could be important in apple resistance against B.dothidea.TEM ultrastructural characterization identified the nuclear morphology of programmed cell death induction in both apple fruit and callus cells under B.dothidea infection.Overexpression of MdVDAC2(MDP0000271281),which encodes an outer-membrane localized anion channel protein in mitochondria,significantly promoted cell death under B.dothidea infection and simultaneously inhibited pathogen infection,suggesting that cell death represents a disease resistance mechanism in apple against B.dothidea infection.Furthermore,BdCatalase(KAF4307763),a cytochromeP450 family protein BdCYP52A4(KAF4300696),and subtilisin-domain containing proteinswere identified fromB.dothidea-secreted proteins,which suggested the potential involvement of active oxygen species and phytoalexins in combating B.dothidea infection and triggering or dampening apple resistance.Collectively,our research suggested that cell wall-mediated penetration resistance,programmed cell death machinery and microbial effector-interrelated signaling were among strategies recruited in apple to combat B.dothidea.The current research laid the foundation for further investigations into resistance mechanisms in apple.

Fusarium pseudograminearum and F.culmorum affect the root system architecture of bread wheat

Yield losses of bread wheat due to crown rot can be more severe when drought conditions occur during the grain-filling period.Root architecture characteristics are important for soil exploration and belowground resource acquisition and are essential for adaptation to water-limited environments.Traits such as root angle,length and density have been strongly associated with acquisition efficiency and contribute to yield stability of the crop.The impact of crown rot pathogens on wheat root architecture is poorly understood.We examined differences in root angle,length and number,as well as dry root weight of the crown rot-susceptible bread wheat cultivar,Livingston inoculated with one of two crown rot pathogens Fusarium culmorum or Fusarium pseudograminearum in a transparent-sided root observation chamber.Significant adverse impacts on plant health and growth were revealed by visual discolouration of the leaf sheaths;fresh and dry shoot weight;leaf area of the oldest and the youngest fully expanded leaf and leaf number.Values of most recorded root system measurements were reduced when inoculated with either F.culmorum or F.pseudograminearum.In contrast,root angle was increased in the presence of F.culmorum but was not significantly changed by F.pseudograminearum.The development of whiteheads and grain losses in bread wheat caused by crown rot have previously been associated with blockages of the vascular systems.The method employed here was able to identify differences in the pathogen impacts on roots,which were not detected using previous systems.This research indicates that in the presence of F.culmorum and F.pseudograminearum infection,not only reductions in the size and biomass of the shoot system but also changes in the length,biomass and architecture of the root system could play an important role in yield loss.

填充密度对非对称Fabry−Pérot纳米腔结构色色相和饱和度的影响

基于Fabry-Pérot(F-P)纳米腔创建的结构色,在高分辨率显示、高密度光学数据存储和防伪等领域有巨大的应用潜力。本研究针对包含不同底层金属材料和中间介质材料的四种非对称F-P纳米腔结构,保持纳米腔尺寸恒定,通过改变周期性纳米腔阵列的填充密度调控结构色的颜色属性,使用时域有限差分法(FDTD)分析探究了填充密度对色相和饱和度的影响。实验结果发现,通过改变填充密度可以有效实现对生成结构色的色相和饱和度的调控,提供了以固定的腔厚度扩展干涉结构色色域的自由度。本研究对使用非对称F-P纳米腔实现广色域、高饱和度和高分辨率的结构色有指导性意义。

基于大运中心重启ROT项目新机制PPP的相关研究

随着我国体育产业发展,体育场馆的兴建数量也逐渐增多。国家出台相关政策,鼓励现有的体育场馆采用ROT模式进行运营,引入社会力量对体育场馆进行改造、运营。但随着运营时间的深入,有不少社会力量由于各式的原因给未来的持续运营造成了不确定的影响,同时相关还在建的配套设施难以继续推进,造成ROT项目的停滞。本文以深圳大运中心为例,由于财务原因,该中心诸多在建未建的配套设施无法继续推进,ROT运营模式难以持续运营下去,鉴于此种情况,区政府计划终止与该集团签订的相关协议,决定采用政府和社会资本合作(PPP)模式,将大运中心主场馆运营权和配套服务设施的投资建设运营权捆绑,利用配套服务设施的经营收入,反哺大运中心主场馆的运营。拟为相关类似项目提供参考。

Isolation,identification and artificial inoculation of Rhizoctonia solani on pear during storage

Pear is a fruit crop of worldwide importance and cold storage is an integral part of the production and distribution of pears.An uncharacterized fungal disease has been observed on‘Huangguan’pear fruit during cold storage in Hebei Province.The fungus was consistently isolated from diseased fruit by routine tissue separation method,and shown to be the causal agent according to Koch postulates.Based on its morphology,molecular characteristics,pathogenicity and ITS sequence,the fungus was identified as Rhizoctonia solani.This study recorded postharvest fruit rot caused by Rhizoctonia solani on pear fruit in China.

Colonization by Klebsiella variicola FH-1 stimulates soybean growth and alleviates the stress of Sclerotinia sclerotiorum

Sclerotinia stem rot,caused by Sclerotinia sclerotiorum,is a destructive soil-borne disease leading to huge yield loss.We previously reported that Klebsiella variicola FH-1 could degrade atrazine herbicides,and the vegetative growth of atrazine-sensitive crops(i.e.,soybean)was significantly increased in the FH-1-treated soil.Interestingly,we found that FH-1 could promote soybean growth and induce resistance to S.sclerotiorum.In our study,strain FH-1 could grow in a nitrogen-free environment,dissolve inorganic phosphorus and potassium,and produce indoleacetic acid and a siderophore.The results of pot experiments showed that K.variicola FH-1 promoted soybean plant development,substantially improving plant height,fresh weight,and root length,and induced resistance against S.sclerotiorum infection in soybean leaves.The area under the disease progression curve(AUDPC)for treatment with strain FH-1 was significantly lower than the control and was reduced by up to 42.2%within 48 h(P<0.001).Moreover,strain FH-1 rcovered the activities of catalase,superoxide dismutase,peroxidase,phenylalanine ammonia lyase,and polyphenol oxidase,which are involved in plant protection,and reduced malondialdehyde accumulation in the leaves.The mechanism of induction of resistance appeared to be primarily resulted from the enhancement of transcript levels of PR10,PR12,AOS,CHS,and PDF1.2 genes.The colonization of FH-1 on soybean root,determined using CLSM and SEM,revealed that FH-1 colonized soybean root surfaces,root hairs,and exodermis to form biofilms.In summary,K.variicola FH-1 exhibited the biological control potential by inducing resistance in soybean against S.sclerotiorum infection,providing new suggestions for green prevention and control.

Changes in concentrations and transcripts of plant hormones in wheat seedling roots in response to Fusarium crown rot

Fusarium crown rot(FCR) is a soilborne disease causing severe yield losses in many wheat-growing areas of the world. Diseased plants show browning and necrosis of roots and stems causing white heads at maturity. Little is known about the molecular processes employed by wheat roots to respond to the disease. We characterized morphological, transcriptional and hormonal changes in wheat seedling roots following challenge with Fusarium pseudograminearum(Fp), the main pathogen of FCR. The pathogen inhibited root development to various extents depending on plants' resistance level. Many genes responsive to FCR infection in wheat roots were enriched in plant hormone pathways. The contents of compounds involved in biosynthesis and metabolism of jasmonic acid, salicylic acid, cytokinin and auxin were drastically changed in roots at five days post-inoculation. Presoaking seeds in methyl jasmonate for 24 h promoted FCR resistance, whereas presoaking with cytokinin 6-benzylaminopurine made plants more susceptible. Overexpression of TaOPR3, a gene involved in jasmonic acid biosynthesis, enhanced plant resistance as well as root and shoot growth during infection.

Elimination of the yellow pigment gene PSY-E2 tightly linked to the Fusarium head blight resistance gene Fhb7 from Thinopyrum ponticum

Fhb7 is a major gene that was transferred from Thinopyrum ponticum to chromosome 7D of wheat(Triticum aestivum)and confers resistance to both Fusarium head blight(FHB)and Fusarium crown rot(FCR).However,Fhb7 is tightly linked to the PSY-E2 gene,which causes yellow flour,limiting its application in breeding.To break this linkage,marker K-PSY was developed for tagging PSY-E2 and used with Fhb7 markers to identify recombination between the two genes.Screening 21,000 BC1F2 backcross progeny(Chinese Spring ph1bph1b*2/SDAU 2028)revealed two Fhb7^(+)wheat-Tp7el_(2)L lines,Shannong 2–16and Shannong 16–1,that carry a desired truncated Fhb7^(+)translocation segment without PSY-E2.The two lines show levels of resistance to FHB and FCR similar to those of the original translocation line SDAU 2028,but have white flour.To facilitate Fhb7 use in wheat breeding,STS markers were developed and used to isolate Fhb7 on a truncated Tp7el_(2) translocation segment.Near-isogenic lines carrying the Fhb7^(+)segment were generated in the backgrounds of three commercial cultivars,and Fhb7^(+)lines showed increased FHB and FCR resistance without yield penalty.The breakage of the tight linkage between Fhb7 and PSY-E2 via homoeologous recombination provides genetic resources for improvement of wheat resistance to FHB and FCR and permit the large-scale deployment of Fhb7 in breeding using marker-assisted selection.

Fungal community structure analysis of peanut pod rot in soil in Hebei Province,China

In recent years,peanut yield and quality are more seriously affected by pod rot disease in China.However,managing this disease has proven challenging due to the wide host range of its pathogens.In this study,four soil samples were collected from fields with pod rot disease in Hebei Province,and 454 pyrosequencing was used to analyze the fungal communities structure within them.All 38490 ITS high-quality sequences were grouped into 1203 operational taxonomic units,the fungal community diversity of four soil samples was evaluated and compared using Shannon index and Simpson index.The results showed that members of Ascomycota were dominant,followed by Basidiomycota.According to the BLAST results at the species level,Guehomyces had the highest abundance,accounting for about 7.27%,followed by Alternaria,Fusarium,and Davidiella.The relative abundance of Fusarium oxysporum isolated from rotting peanuts in soil with peanut rot was higher than that in the control,indicating that Fusarium oxysporum might be one of the main pathogenic fungus of peanut rot in this area.This study delved into the broader fungal community associated with peanut pod rot,providing a theoretical foundation for preventing and treating this disease in agriculture.