Influence of Irregular Coastlines on a Tornadic Mesovortex in the Pearl River Delta during the Monsoon Season. Part Ⅰ:Pre-storm Environment and Storm Evolution

The Pearl River Delta(PRD),a tornado hotspot,forms a distinct trumpet-shaped coastline that concaves toward the South China Sea.During the summer monsoon season,low-level southwesterlies over the PRD’s sea surface tend to be turned toward the west coast,constituting a convergent wind field along with the landward-side southwesterlies,which influences regional convective weather.This two-part study explores the roles of this unique land–sea contrast of the trumpet-shaped coastline in the formation of a tornadic mesovortex within monsoonal flows in this region.Part I primarily presents observational analyses of pre-storm environments and storm evolutions.The rotating storm developed in a lowshear environment(not ideal for a supercell)under the interactions of three air masses under the influence of the land–sea contrast,monsoon,and storm cold outflows.This intersection zone(or“triple point”)is typically characterized by local enhancements of ambient vertical vorticity and convergence.Based on a rapid-scan X-band phased-array radar,finger-like echoes were recognized shortly after the gust front intruded on the triple point.Developed over the triple point,they rapidly wrapped up with a well-defined low-level mesovortex.It is thus presumed that the triple point may have played roles in the mesovortex genesis,which will be demonstrated in Part II with multiple sensitivity numerical simulations.The findings also suggest that when storms pass over the boundary intersection zone in the PRD,the expected possibility of a rotating storm occurring is relatively high,even in a low-shear environment.Improved knowledge of such environments provides additional guidance to assess the regional tornado risk.

Influence of Irregular Coastlines on a Tornadic Mesovortex in the Pearl River Delta during Monsoon Season.Part II:Numerical Experiments

As demonstrated in the first part of this study(Part I),wind-shift boundaries routinely form along the west coast of the Pearl River Delta due to the land-sea contrast of a“trumpet”shape coastline in the summer monsoon season.Through multiple numerical simulations,this article(Part II)aims to examine the roles of the trumpet-shaped coastline in the mesovortex genesis during the 1 June 2020 tornadic event.The modeling reproduced two mesovortices that are in close proximity in time and space to the realistic mesovortices.In addition to the modeled mesovortex over the triple point where strong ambient vertical vorticity was located,another mesovortex originated from an enhanced discrete vortex along an airmass boundary via shear instability.On the fine-scale storm morphology,finger-like echoes preceding hook echoes were also reproduced around the triple point.Results from sensitivity experiments suggest that the unique topography plays an essential role in modifying the vorticity budget during the mesovortex formation.While there is a high likelihood of an upcoming storm evolving into a rotating storm over the triple point,the simulation's accuracy is sensitive to the local environmental details and storm dynamics.The strengths of cold pool surges from upstream storms may influence the stretching of low-level vertically oriented vortex and thus the wrap-up of finger-like echoes.These findings suggest that the trumpet-shaped coastline is an important component of mesovortex production during the active monsoon season.It is hoped that this study will increase the situational awareness for forecasters regarding regional non-mesocyclone tornadic environments.

施肥对盐碱地饲用燕麦根际土壤微生物多样性的影响

为了探究不同施肥模式对盐碱地饲用燕麦(Avena sativa L.)根际土壤微生物多样性的影响,本文设置盐碱地饲用燕麦‘甜燕1号’不施肥、施用常规肥和控释肥模式,基于16S rRNA和内转录间隔区(Internal transcribed spacer,ITS)基因高通量测序技术分别对根际土壤细菌和真菌多样性进行生物信息学分析。结果显示,施肥比不施肥模式增加了根际土壤细菌和真菌的α和β多样性,其中控释肥模式下细菌和真菌群落的操作性分类单元(Operational taxonomic unit,OTU)数量最高。3种施肥模式下优势细菌门均为放线菌门(Actinobacteria)和变形杆菌门(Proteobacteria),优势真菌门均为子囊菌门(Ascomycota)和担子菌门(Basidiomycota)。相关性分析表明,细菌和真菌的优势菌门相对丰度与pH值和全盐含量呈负相关关系,与土壤养分中的全磷含量相关性最高。综上,施肥改变了根际土壤细菌和真菌群落的多样性,且施控释肥比施常规肥提高了饲用燕麦根际土壤微生物多样性。研究结果可为盐碱地饲用燕麦施肥模式的选择提供理论支撑。

Fiber-specific increase of carotenoid content promotes cotton fiber elongation by increasing abscisic acid and ethylene biosynthesis

Cotton fiber is a raw material for the global textile industry and fiber quality is essential to its industrial application.Carotenoids are plant secondary metabolites that may serve as dietary components,regulate light harvesting,and scavenge reactive oxygen species.Although carotenoids accumulate predominantly in rapidly elongating cotton fibers,their roles in cotton fiber development remain poorly understood.In this study,a fiber-specific promoter proSCFP was applied to drive the expression of GhOR1Del,a positive regulator of carotenoid accumulation,to upregulate the carotenoid level in cotton fiber in planta.Fiber length,strength,and fineness were increased in proSCFP:GhOR1Del transgenic cotton and abscisic acid(ABA)and ethylene contents were increased in elongating fibers.The ABA downstream regulator GhbZIP27a stimulated the expression of the ethylene synthase gene GhACO3 by binding to its promoter,suggesting that ABA promoted fiber elongation by increasing ethylene production.These findings suggest the involvement of carotenoids and ABA signaling in promoting cotton fiber elongation and provide a strategy for improving cotton fiber quality.

Evaluation of Beta-Lactam Antibiotics on the Regeneration of Peanut Plants and Their Inhibitory Effect on Agrobacterium Growth

The effect of beta-lactam antibiotics on shoot induction and plantlet regeneration from cotyledonary nodes was tested using two peanut cultivars.The culture media contained 4 mg/L 6-benzylaminopurine(BAP)as the main growth regulator.Various concentrations(100–600 mg/L)of cefotaxime,carbenicillin,and timentin were applied in the culture media.In all the tested media,there were no significant differences in the shoot induction as compared to the control.However,little phytotoxic effect was observed at higher concentrations of these antibiotics in the shoot elongation media.Under shoot elongation medium,shoots turned brownish and partly died at higher concentrations where shooting rates were not affected by the treatments.In cefotaxime,timentin,and carbenicillin-containing media,levels of antibiotics greater than 400,300,and 200 mg/L,respectively resulted in the brown coloration of plantlets.Moreover,the mean shoot number and shoot weight significantly decreased as their dosage increased.The results indicate that maximum levels of antibiotics have an adverse effect on the growth and development of peanuts.Also,cefotaxime(100–300 mg/L)and timentin(100–300 mg/L)will be sufficient in controlling Agrobacterium growth in the culture media with the least phytotoxic effect on the peanut plants.

Comparative analysis of the complete chloroplast genome among Prunus mume,P.armeniaca,and P.salicina

Prunus mume Sieb.et Zucc.,P.armeniaca L.,and P.salicina L.are economically important fruit trees in temperate regions.These species are taxonomically perplexing because of shared interspecific morphological traits and variation,which are mainly attributed to hybridization.The chloroplast is cytoplasmically inherited and often used for evolutionary studies.We sequenced the complete chloroplast genomes of P.mume,P.armeniaca,and P.salicina using Illumina sequencing followed by de novo assembly.The three chloroplast genomes exhibit a typical quadripartite structure with conserved genome arrangement,structure,and moderate divergence.The lengths of the genomes are 157,815,157,797,and 157,916 bp,respectively.The length of the large single-copy region(LSC)region is 86,113,86,283,and 86,122 bp,and the length of the SSC region is 18,916,18,734,and 19,028 bp;the IR region is 26,393,26,390,and 26,383 bp,respectively.Each of the three chloroplast genomes encodes 133 genes,including 94 protein-coding,31 tRNA,and eight rRNA genes.Differential gene analysis for the three species revealed that trnY-ATA is a unique gene in P.armeniaca;in contrast,the gene trnI-TAT is only present in P.mume and P.salicina,though the position of the gene in these chloroplast genomes differs.Further comparative analysis of the complete chloroplast genome sequences revealed that the ORF genes and the sequences of linked regions rps16 and atpA,atpH and atpI,trnc-GCA and psbD,ycf3 and atpB,and rpL32 and ndhD are significantly different and may be used as molecular markers in taxonomic studies.Phylogenetic evolution analysis of the three species suggests that P.mume has a closer genetic relationship to P.armeniaca than to P.salicina.

Vertical Evolution of Boundary Layer Volatile Organic Compounds in Summer over the North China Plain and the Differences with Winter

The vertical observation of volatile organic compounds(VOCs)is an important means to clarify the mechanisms of ozone formation.To explore the vertical evolution of VOCs in summer,a field campaign using a tethered balloon during summer photochemical pollution was conducted in Shijiazhuang from 8 June to 3 July 2019.A total of 192 samples were collected,23 vertical profiles were obtained,and the concentrations of 87 VOCs were measured.The range of the total VOC concentration was 41-48 ppbv below 600 m.It then slightly increased above 600 m,and rose to 58±52 ppbv at 1000 m.The proportion of alkanes increased with height,while the proportions of alkenes,halohydrocarbons and acetylene decreased.The proportion of aromatics remained almost unchanged.A comparison with the results of a winter field campaign during 8-16 January 2019 showed that the concentrations of all VOCs in winter except for halohydrocarbons were more than twice those in summer.Alkanes accounted for the same proportion in winter and summer.Alkenes,aromatics,and acetylene accounted for higher proportions in winter,while halohydrocarbons accounted for a higher proportion in summer.There were five VOC sources in the vertical direction.The proportions of gasoline vehicular emissions+industrial sources and coal burning were higher in winter.The proportions of biogenic sources+long-range transport,solvent usage,and diesel vehicular emissions were higher in summer.From the surface to 1000 m,the proportion of gasoline vehicular emissions+industrial sources gradually increased.

Kinetic analysis of austenite transformation for B1500HS high-strength steel during continuous heating

The dilatometric curves of B1500HS high-strength steel at different heating rates were measured by a Gleeble-3800 thermal simulator and analyzed to investigate the effect of heating rate on austenitization.Results show that the value of starting temperature and ending temperature of austenite transformation increase with the rise of heating rates,whereas the temperature interval of austenite formation decreases.The kinetic equation of austenite transformation was solved using the Johnson–Mehl–Avrami model,and the related parameters of the equation were analyzed by the Kissinger method.For those calculations,the activation energy of austenite transformation is 1.01×10^6 J/mol,and the values of kinetic parameters n and ln k0 are 0.63 and 103.03,respectively.The relationship between the volume fraction of austenite and the heating time at different heating rates could be predicted using the kinetic equation.The predicted and experimental results were compared to verify the accuracy of the kinetic equation.The microstructure etched by different corrosive solutions was analyzed,and the reliability of kinetic equation was further verified from the microscopic perspective.

Formation Mechanism and Occurrence Law of Pod Shattering in Soybean:A Review

Seed shattering refers to the phenomenon in which the pods split along the abdominal and back sutures before the crop is received,so that the seeds are spread.Seed shattering is vital to the reproduction of their offspring in wild plants,but it is also the main cause of crop yield loss reason.Pod-explosion resistance is a complex process of physical and physiological and biochemical reactions.Soybean seed shattering phenomenon is widespread,which severely restricts the development of soybean industry.Seed shattering(pod cracking or fruit dropping)is essential for the reproduction of its offspring in wild plants,but it is also the main cause of crop yield loss.This article analyzes the morphology and structure of pods related to seed shattering from the morphology of pods.On the basis of the regularity of the occurrence of seed shattering and the summary of phenotypic index identification methods,physiologically introduced the regulation mechanism of key enzymes and endogenous hormones on seed shattering.The localization,labeling and cloning of seed shattering genes are introduced in molecular biology.The study focused on reviewing the latest advances in the research on soybean seed shattering characteristics,and discussed with the research results of related crops.Finally,the research and application of soybean seed shattering resistance were prospected for several aspects.

铝合金变速器壳体消失模铸造浇注系统优化设计

以15641015-3C铝合金变速器壳体为例,对比分析不同浇注系统对铸件质量的影响,并针对缺陷对浇注系统进行工艺优化,减少消失模铸造铸件浇不足、缩松和气孔的现象,提高了变速器壳体铸件的合格率。

Combination of 6-Benzylaminopurine and Thidiazuron Promotes Highly Efficient Shoot Regeneration from Cotyledonary Node of Mature Peanut (Arachis hypogaea L.) Cultivars

Efficient in vitro plantlet regeneration is an important step to successfully transform genes for the improvement of agronomic traits.A combination of 6-benzylaminopurine(BAP)and thidiazuron(TDZ)plant growth regulators was applied to evaluate shoot regeneration capacity whereasα-naphthalene acetic acid(NAA)combination with 6-benzylaminopurine(BAP),and 2,4-dichlorophenoxyacetic acid(2,4-D)with 6-benzylaminopurine were tested to optimize root induction for two peanut cultivars.The result showed combination(BAP with TDZ)was found to be effective in promoting shoot.The highest shoot regeneration frequency(93%)was obtained on a medium supplemented with 4 mg/L BAP and 0.5 mg/L TDZ while an average regeneration frequency(87%)was achieved in a medium containing combinations of 2 mg/L BAP with 1 mg/L TDZ.The shooting rate increased for both cultivars as the concentrations of BAP increased and TDZ decreased.The highest rooting rate(93%)was obtained on a medium supplemented with 3.5 mg/L NAA with 2.5 mg/L BAP for both cultivars.The rooting rate increased as the concentration of auxin to cytokinin ratio increased.The maximum rooting rate(83%)was obtained on MS medium supplemented with 0.3 mg/L 2,4-D with 0.2 mg/L BAP for the cultivar N3.The result indicated that BAP with NAA was much better than BAP with 2,4-D in rooting rate.Thus,the protocol developed was genotype independent and effective for peanut tissue culture.

A New Rearrangement Reaction of 2-Phenyl Substituted Benzothiazepine with Ethoxycarbonyl Carbene─Mechanism of the Reaction and Structure of the Product

2,3-Dihydro-2-phenyl-4-(4-methoxyphenyl)-1, 5-benzothiazepine reacts with ethoxycarbonyl carbene to give an unexpected compound 2,3-disubstituted-4H-1,4-benzothiazine Ⅲ. It was found to be a new rearrangement reaction and the structure of the product was confirmed by IR, NMR, MS.

Cloning and Drought Resistance Analysis of Soybean GmHsps_p23-like Gene

Soybean(Glycine max(L.)Merr.)is an important cultivated crop,which requires much water during its growth,and drought seriously affects soybean yields.Studies have shown that the expression of small heat shock proteins can enhance drought resistance,cold resistance and salt resistance of plants.In this experiment,soybean GmHsps_p23-like gene was successfully cloned by RT-PCR,the protein encoded by the GmHsps_p23-like gene was subjected to bioinformatics analysis,and the pCAMBIA3301-GmHsps_p23-like overexpression vector and pCBSG015-GmHsps_p23-like gene editing vector were constructed.Agrobacterium-mediated method was used to transform soybeans to obtain positive plants.RT-PCR detection,rehydration experiment and drought resistance physiological and biochemical index detection were performed on the T2 generation positive transgenic soybean plants identified by PCR and Southern hybridization.The results showed that the overexpression vector plant GmHsps_p23-like gene expression increased.After rehydration,the transgenic overexpression plants returned to normal growth,and the damage to the plants was low.After drought stress,the SOD and POD activities and the PRO content of the transgenic overexpression plants increased,while the MDA content decreased.The reverse was true for soybean plants with genetically modified editing vectors.The drought resistance of the overexpressed soybeans under drought stress was higher than that of the control group,and had a stronger drought resistance.It showed that the expression of soybean GmHsps_p23-like gene can improve the drought resistance of soybean.The cloning and functional verification of soybean GmHsps_p23-like gene had not been reported yet.This is the first time that PCR technology has been used to amplify the soybean GmHsps_p23-like gene and construct an expression vector for this gene.This research has laid the foundation for transgenic technology to improve plant drought resistance and cultivate new drought-resistant transgenic soybean varieties.

Character Identification of an Early Flowering Mutant

The concept of gene-function-genetic trait was introduced to explore the effects of early flowering on the growth and development of maize at the jointing stage and to obtain early flowering mutants using ethyl methanesulfonate mutagenesis.First,we studied gene expression,phytohormones,and lignin content to explore the physiological peculiarities of the early flowering mutant.Then we analyzed the genetic features of the mutants during the jointing stage by measuring physiological and biochemical indices of drought tolerance.The results showed that the photosynthetic rate of the mutant was significantly higher than that of the control and the rate of accumulation of dry matter was rapid.In addition,the lignin content increased while drought resistance diminished.Therefore,we concluded that early flowering leads to faster overall growth and development.

消失模铸造球墨铸铁减速机壳体夹杂及缩孔消除研究

消失模铸造生产球墨铸铁减速机壳体,减速机壳体端面出现夹杂和缩孔缺陷。通过在铸件端面增加余量,解决了减速机壳体端面的夹杂。探索出散热新工艺和柔性冷铁工艺,并严格控制铸造过程负压,解决铸件热节区域缩孔缺陷。实验结果表明,散热工艺和柔性冷铁工艺均能够解决消失模铸造球墨铸铁减速机壳体缩孔缺陷,并且工艺简单,工艺出品率高。

Advances on pathogenesis of migraine in cold regions

Migraine is a common primary headache which seriously affects the quality of patients’life due to the high prevalence and disability rate.Recent years a large number of studies have found that temperature is directly bound to migraine and migraine patients in cold regions have higher prevalence,different manifestations and poor response to the conventional therapy.We propose in this review article a new concept of migraine in cold regions on the basis of geography and summarize the research advances on the pathogenesis of migraine in cold regions to provide conceptual basis for the clinical diagnosis and treatment of this disease entity.

Advances in Periprocedural Anticoagulation for Percutaneous Coronary Interventions

Percutaneous coronary intervention (PCI) is commonly used in the surgical treatment of patients with various types of cardiac diseases. Some patients require long-term anticoagulation in the presence of deep vein thrombosis, atrial fibrillation and mechanical heart valves, and inappropriate anticoagulation during the perioperative period may lead to bleeding events or thrombotic events. In this paper, the importance of anticoagulation in the practical application of percutaneous coronary intervention (PCI) is first introduced, and then the various drug regimens used in the perioperative anticoagulation of percutaneous coronary intervention are explored in detail in the light of current research advances, with a view to providing guidance for clinical practice.

Exploring formation mechanism and source attribution of ozone during the 2019 Wuhan Military World Games:Implications for ozone control strategies

A series of emission reduction measures were conducted in Wuhan,Central China,to ensure good air quality during the 7th Military World Games(MWG)in October 2019.To better understand the implications for ozone(O_(3))pollution control strategies,we applied integrated analysis approaches based on the de-weathered statistical model,parameterization methods,chemical box model,and positive matrix factorization model.During the MWG,concentrations of O_(3),NO_x,and volatile organic compound(VOCs),OFP(O_(3)formation potential),L_(OH)(OH radical loss rate)were 83μg/m^(3),43μg/m^(3),26 ppbv,188μg/m^(3),and 3.9 s^(-1),respectively,which were 26%,18%,3%,15%,and 13%lower than pre-MWG values and 6%,39%,30%,33%,and 50%lower than post-MWG values,respectively.After removing meteorological influence,O_(3)and its precursors during the MWG decreased largely compared with post-MWG values,and only O_(3),NO_(2),and oxygenated VOCs(OVOCs)declined compared with pre-MWG values,which revealed the emission reduction measures during the MWG played an important role for O_(3)decline.For six VOCs sources,the mass contributions of biomass burning and solvents usage during the MWG decreased largely compared with pre-MWG values.O_(3)production was sensitive to VOCs and the key species were aromatics,OVOCs,and alkenes,which originated mainly from solvents usage,biomass burning,industrial-related combustion,and vehicle exhaust.Decreasing O_(3)concentration during the strict control was mainly caused by OVOCs reduction due to biomass burning control.Generally,the O_(3)abatement strategies of Wuhan should be focused on the mitigation of high-reactivity VOCs.

Vertical distributions of VOCs in the Tibetan Plateau background region

Exploring the vertical variation in volatile organic compounds(VOCs)in background regions can provide infor-mation on the spatial distribution of pollutants,providing a scientific basis for atmospheric pollution prevention and control strategies.From 15 August to 5 September 2023,at the Southeast Tibet Mountain Comprehensive Environmental Observation Station(SETS),a tethered balloon was used to sample VOCs every 100 m from the ground to 1000 m.A total of 403 air bag samples were collected,and 39 vertical profiles of VOCs were obtained.Ninety-two VOC species were detected.The VOC concentration at the SETS did not change significantly verti-cally,and the average VOC concentration was 11.1±2.4 ppbv.The main components were alkanes(51.4%),alkenes(18.7%),and halohydrocarbons(18.1%).There was no obvious diurnal change in VOCs and no signif-icant difference between the different layers.When the surface VOC concentration was less than 10 ppbv,the concentrations,components,and sources of VOCs were evenly distributed vertically,and the main sources of VOCs at different heights were vehicle exhaust and background.When the surface VOC concentration exceeded 10 ppbv,the VOC concentration gradually decreased with height.The proportion of alkanes in surface VOCs in-creased,and the source was mainly vehicle exhaust.This study confirmed that VOCs are vertically homogeneous in the background of the Tibetan Plateau,emphasizing the importance of vehicle emissions as a potential source of VOCs.

Characteristics of interior noise of a Chinese high-speed train under a variety of conditions

This paper presents an investigation into the characteristics of interior noise of a Chinese high-speed train under several typical conditions. Interior noises within Vehicle TC01, which can be used as a head car or an end car, and Vehicle TP03, the third car counting from TC01, are measured for the train running at speeds from 260 km/h to 385 km/h, along two types of track including a slab track and a ballast track and either on the ground surface or in a tunnel. Data analyses are performed for sound pressure overall levels, frequency, area contributions, and possible generation mechanisms, showing how they are affected by train speed, running direction, track type, and tunnel. The results show that, whether TC01 is used as head car or end car, the interior noise characteristics in the VIP cabin are mostly related to aerodynamic noise. Differences in interior noise between tracks become smaller as the train speed increases. The effect of a tunnel on the interior noise is more important for the middle coach than that for the head coach. This study can provide a basis for noise control of high-speed trains.