目的:探究Er∶YAG激光光子增强的光声流(SWEEPS)技术在不同脉冲间隔参数条件下的蒸汽气泡动力学效应.方法:Er∶YAG激光手具连接工作尖放置于自由水域模型中,设置SWEEPS模式,150～600μs脉冲间隔激活.高速摄像机(200 000 Hz)摄录Er∶YAG激光激活荡洗引起空穴效应的过程,matlab逐帧分析蒸汽气泡间的相互作用关系,及蒸汽气泡消失时刻气泡残余与激光工作尖之间的距离.实验数据经SPSS 19.0统计软件进行统计分析.结果:在自由水域中,Er∶YAG激光SWEEPS模式下,脉冲间隔设置的改变会引起两次脉冲激发的蒸汽气泡形成不同的相互作用关系,包括双气泡融合、双气泡撞击及双气泡脱离.其中,脉冲间隔设置为360-440μs时,双气泡撞击现象会使蒸汽气泡消失时气泡残余与激光工作尖之间达到最远距离.结论:在自由水域中,Er∶YAG激光双脉冲SWEEPS模式在不同的脉冲间隔设置下会引起双气泡间形成不同的作用关系,该现象可能可以增强Er∶YAG激光空穴效应,强化激光激活荡洗的临床应用效果.

目的:评价超声、声波及激光活化技术对细菌生物膜的清除效果.方法:选取健康志愿者龈上及龈下菌斑,羟基磷灰石(hydroxyapatite,HAP)片包被胶原作为载体,厌氧培养21 d形成细菌生物膜,分为对照组和实验组,实验组分别应用传统注射器冲洗(conventional needle irrigation,CNI)、被动超声冲洗(passive ultrasonic irriga-tion,PUI)、EDDY声波冲洗、Nd∶YAG激光、半导体(Diode)激光、Er∶YAG激光光子引导光声流(photon-initiated photoacoustic streaming,PIPS)和光波增强光声流(shock wave enhanced emission photoacoustic streaming,SWEEPS)联合1％次氯酸钠(NaOCl)处理,刮取HAP片上细菌生物膜,梯度稀释后厌氧37 ℃ 恒温培养72 h后进行菌落计数,同时采用荧光定量聚合酶链反应(PCR)方法对细菌通用基因及中间链球菌(Streptococcus intermedi-us,S.i)基因的拷贝数进行检测.采用SPSS 22.0软件进行统计分析.结果:初始可培养细菌数为(11.33士2.50)×108 CFU/mL,CNI组平均杀菌率最低为71.23％,Nd∶YAG及Diode激光平均杀菌率分别为86.46％和87.06％,显著高于CNI组(P＜0.01).PUI、EDDY及PIPS平均杀菌率达98.43％、99.11％及99.34％,均显著高于CNI组、Nd∶YAG组及Diode激光组(P＜0.01).SWEEPS杀菌率最高达99.93％,与各组比较差异有统计学意义(P＜0.05或P＜0.01).SWEEPS组细菌通用基因及S.i基因拷贝数最少,与对照组、CNI组、Nd∶YAG组及Diode激光组比较差异有统计学意义(P＜0.05).结论:激光活化次氯酸钠冲洗液可显著提高对细菌生物膜的灭菌效果,其中Er∶YAG激光SWEEPS模式杀菌率最高.

目的 探究影响胸段食管癌、贲门癌淋巴结转移的临床因素.方法 回顾性分析65例经手术治疗的胸段食管癌、贲门癌患者临床资料,分析胸段食管癌、贲门癌各区域淋巴结转移情况,采用单因素分析及 Logistic 回归分析病理因素对淋巴结转移的影响.结果 胸段食管癌以上纵隔、肺门,隆突下较为多见;贲门癌转移主要以腹腔、贲门周围多见.对患者年龄、肿瘤细胞病理类型,肿瘤浸润深度,长度,分化程度等进行单因素分析,结果提示肿瘤浸润全层,长度超过5 cm以及细胞分化程度低、位于胸下段的肿瘤和淋巴清扫个数>3与淋巴结转移相关(P<0.05).将上述有意义的单因素纳入多因素Logistic回归分析,结果提示,肿瘤分化程度,长度,浸润深度为淋巴结转移的独立影响因素(P<0.05).结论 食管癌、贲门癌的淋巴结转移是具有一定的特点,术前全面合理的检查,根据肿瘤分化程度,病变长度,浸润深度等实际情况制定淋巴结清扫范围.

Chinese cabbage is the most consumed leafy crop in East Asian countries.However,premature bolting induced by continuous low temperatures severely decreases the yield and quality of the Chinese cabbage,and therefore restricts its planting season and geographic distribution.In the past 40 years,spring Chinese cabbage with strong winterness has been selected to meet the market demand.Here,we report a genome variation map of Chinese cabbage generated from the resequencing data of 194 geographically diverse accessions of three ecotypes.In-depth analyses of the selection sweeps and genome-wide patterns revealed that spring Chinese cabbage was selected from a specific population of autumn Chinese cabbage around the area of Shandong peninsula in northern China.We identified 23 genomic loci that underwent intensive selection,and further demonstrated by gene expression and haplotype analyses that the incorporation of elite alleles of VERNALISATION INSENTIVE 3.1 (BrVlN3.1) and FLOWER LOCUS C 1 (BrFLC1) is a determinant genetic source of variation during selection.Moreover,we showed that the quantitative response of BrVIN3.1 to cold due to the sequence variations in the cis elements of the BrVlN3.1 promoter significantly contributes to bolting-time variation in Chinese cabbage.Collectively,our study provides valuable insights into the genetic basis of spring Chinese oabbage selection and will facilitate the breeding of bolting-resistant varieties by molecular-marker-assisted selection,transgenic or gene editing approaches.

In this issue,Wu et al.(2019) describe the largest whole-genome resequencing dataset published to date for rapeseed (Brassica napus),an allopolyploid crop species that originated just a few thousand years ago under anthropogenic influence and rapidly evolved into one of the world's most important oilseed crops.In almost 1000 accessions spanning species-wide germplasm for oilseed rape,a comprehensive analysis of sequence diversity related to flowering-related traits uncovered selective sweeps associated with eco-geographic adaptation and human selection,attributable particularly to divergence among homoeologs of key flowering-time regulation and ethylene synthesis/ signaling genes.The authors further extend their analysis to retrospective,genome-based documentation of diversity footprints that trace the global expansion of the species across a century of breeding.The study contributes not only a rich catalog of genome-wide diversity for genetic analysis and future breeding of important agro-econornic traits but also a unique conceptional framework for ongoing selective adaptation of oilseed rape crops to emerging challenges presented by chang ing climatic conditions in key production areas.Selective sweeps were found to contain genes involved in stress adaptation and development,especially flowering time,indicating that climatic adaptation both in terms of local stress factors and of life-cycle adaptation was the major factor underlying agronomic selection for improved seed yield.

Maize is a globally important crop that was a classic model plant for genetic studies.Here,we report a 2.2 Gb draft genome sequence of an elite maize line,HuangZaoSi (HZS).Hybrids bred from HZS-improved lines (HILs) are planted in more than 60％ of maize fields in China.Proteome clustering of six completed sequenced maize genomes show that 638 proteins fall into 264 HZS-specific gene families with the majority of contributions from tandem duplication events.Resequencing and comparative analysis of 40 HZS-related lines reveals the breeding history of HILs.More than 60％ of identified selective sweeps were clustered in identity-by-descent conserved regions,and yield-related genes/QTLs were enriched in HZS characteristic selected regions.Furthermore,we demonstrated that HZS-specific family genes were not uniformly distributed in the genome but enriched in improvement/function-related genomic regions.This study provides an important and novel resource for maize genome research and expands our knowledge on the breadth of genomic variation and improvement history of maize.

The new bird inspired wing sweep was introduced and compared with straight and conventional swept wings in gliding flight by an experimental test setup.Due to the similarity with the birds' wing,all test models have S 1223 airfoil.Swept models inspired from the bird consist of two parts:the straight part near the root and the swept part near the tip.Aerodynamic forces on each wing were measured from 0° to 24° angles of attack and Reynolds numbers of 4.3× 104,8.6× 104,1.3× 105,and 1.7× 105.Wind tunnel test results show that wings with an innovative sweep at α ＞ 0 have more lift for Reynolds numbers between 4.3 × 104 and 8.6 × 104.Also,innovative sweep increases the stall angle,and the wing did not stall until α =24° for Reynolds between 1.3× 105 and 1.7× 105.An increase in lift and having sufficient aerodynamic performance in low Reynolds numbers for birds' inspired wing sweep in gliding flight may be the answer to why the wing sweep of birds is not like conventional sweeps.

Next-generation sequencing has yielded a vast amount of cattle genomic data for global characterization of population genetic diversity and identification of genomic regions under natural and artificial selection. However, efficient storage, querying, and visualization of such large datasets remain challenging. Here, we developed a comprehensive database, the Bovine Genome Variation Database (BGVD). It provides six main functionalities:gene search, variation search, genomic sig-nature search, Genome Browser, alignment search tools, and the genome coordinate conversion tool. BGVD contains information on genomic variations comprising ～60.44 M SNPs, ～6.86 M indels, 76,634 CNV regions, and signatures of selective sweeps in 432 samples from modern cattle worldwide. Users can quickly retrieve distribution patterns of these variations for 54 cattle breeds through an interactive source of breed origin map, using a given gene symbol or genomic region for any of the three versions of the bovine reference genomes (ARS-UCD1.2, UMD3.1.1, and Btau 5.0.1). Signals of selection sweep are displayed as Manhattan plots and Genome Browser tracks. To further investigate and visualize the relationships between variants and signatures of selection, the Genome Browser integrates all variations, selection data, and resources, from NCBI, the UCSC Genome Browser, and Animal QTLdb. Collectively, all these features make the BGVD a useful archive for in-depth data mining and analyses of cattle biology and cattle breeding on a global scale. BGVD is publicly available at http://animal.nwsuaf.edu.cn/BosVar.

目的 比较Er:YAG激光中的SWEEPS模式(shock wave enhanced emission photoacoustic streaming,SWEEPS)和超声非切割(passive ultrasonic irrigation,PUI)两种荡洗方式对根管内粪肠球菌(Enterococcus faecalis,E.faecalis)生物膜的清除作用.方法 选择人新鲜拔除的单根前磨牙共250颗,去除管壁玷污层,高温高压灭菌,建立E.faecalis感染模型.随机分为6组(n=40),SWEEPS?Er:YAG激光联合3％NaClO,SWEEPS?Er:YAG激光联合0.9％生理盐水,PUI联合3％NaClO,PUI联合0.9％生理盐水作为实验组,3％NaClO和0.9％生理盐水组作为对照组.扫描电镜(scanning electron microscopy,SEM)定性观察两种方式细菌清除作用,平板细菌计数法定量检测两种方式细菌减少率,非参数检验进行统计学分析.结果 与荡洗前比,SWEEPS+NaClO组、SWEEPS+生理盐水组、PUI+NaClO组、PUI+生理盐水组、3％NaClO组在荡洗后E.faecalis菌量显著降低(P<0.05),组间比较有统计学差异(P<0.05),细菌减少率SWEEPS+NaClO组>SWEEPS+生理盐水组>PUI+NaClO组>PUI+生理盐水组>NaClO组>生理盐水组.结论 SWEEPS?Er:YAG激光荡洗对于根管内粪肠球菌生物膜的清除作用明显优于超声非切割荡洗.

目的 观察不同Er∶YAG激光技术对根管内壁玷污层的清理能力,探究光子增强的光声流效应(shock wave enhanced emission photoacoustic streaming,SWEEPS)技术对根管内壁玷污层的清理效果.方法 示波器精确测定Er∶ YAG激光不同工作模式的脉冲波形.收集人离体第三磨牙(85颗),使用机用ProTaper Universal镍钛锉进行根管预备至30号(锥度0.09),建立玷污层模型,并使用5.25％次氯酸钠在预备过程中进行冲洗.分别应用Er∶ YAG激光SWEEPS技术与光子诱导的光声流效应(photon-induced photoacoustic streaming,PIPS)技术激活17％EDTA,清理离体牙根管内壁玷污层30s和60s.将激光激活荡洗后的样本沿牙体组织长轴纵向劈开,扫描电镜分别观察距离根尖孔1、4及8 mm的根管内表面并进行评分.红外热像仪记录两种不同Er∶YAG激光技术激活荡洗时离体牙外表面的温度变化.结果 SWEEPS技术是一种双脉冲Er∶YAG激光工作模式,该技术对距离根尖孔4 mm及1 mm的玷污层清理效果优于PIPS技术(P＜0.05).红外热像仪检测发现两种Er∶ YAG激光技术在激活荡洗过程中对牙周膜的热负效应差异无统计学意义(P＞0.05).结论 与PIPS技术相比,应用Er∶YAG激光SWEEPS技术可对根中段及根尖段玷污层有更好的清理效果,同时不增加对牙周膜的热负效应.