Development of a low-frequency magnetic lightning mapping system(LFM-LMS)in North China:validation and preliminary results

A low-frequency magnetic lightning mapping system(LFM-LMS)was built during the SHAndong Triggered Lightning Experiment(SHATLE),based on continuous measurements of magnetic field radiation from lightning.The hardware and source-mapping techniques used by the LFM-LMS were introduced;both Monte Carlo simulations and the observation of rocket-triggered lightning examples were employed to examine the location accuracy and detection effectiveness of the LFM-LMS.We estimated that the system’s location accuracy about 100−200 m horizontally and~200 m vertically.A natural intra-cloud lightning flash and a rocket-triggered lightning flash,both with intricate structures and discharging processes,were examined using the three-dimensional mapping results.The progressing path of negative lightning leaders is usually well-defined,and its propagation speed is estimated to be(0.5−1.4)×10^(6)m/s.In summary,the LFM-LMS can reconstruct the three-dimensional morphology of lightning flashes;this technology provides a efficient method for investigating the characteristics of lightning development,as well as the overall electrical strucuture of thunderstorms.

Simultaneous Localization and Mapping System Based on Labels

In this paper a label-based simultaneous localization and mapping（ SLAM） system is proposed to provide localization to indoor autonomous robots. In the system quick response（ QR） codes encoded with serial numbers are utilized as labels. These labels are captured by two webcams,then the distances and angles between the labels and webcams are computed. Motion estimated from the two rear wheel encoders is adjusted by observing QR codes. Our system uses the extended Kalman filter（ EKF） for the back-end state estimation. The number of deployed labels controls the state estimation dimension. The label-based EKF-SLAM system eliminates complicated processes,such as data association and loop closure detection in traditional feature-based visual SLAM systems. Our experiments include software-simulation and robot-platform test in a real environment. Results demonstrate that the system has the capability of correcting accumulated errors of dead reckoning and therefore has the advantage of superior precision.

Recording of Monophasic Action Potentials in Swine Using a Modified-tip Platinum Ablation Catheter and Electroanatomical Mapping System(摘要 )

Objective:In this study, the feasibility to evaluate the global myocardial activation and repolarization sequence using the electroanatomical mapping system and MAP recording technique via the modified platinum catheter was explored in swine. Methods:Ten healthy pigs (50-55 kg) were anaesthetized with pentobarbital and catamine, intubated and ventilated. Four vascular accesses were obtained. A modified small tip ablation catheter (Navi-Star, Biosense Webster), the end surface of tip electrode was 0.81 mm 2 and 1 mm in diameter, was used for MAP recording. The MAP electrograms were recorded between the tip (exploring electrode) and the ring electrode proximal to the tip (indifferent electrode). The catheter was intentionally positioned perpendicular to endocardium with slight contact pressure to allow MAP recording with a satisfactory amplitude and morphology. All MAP recordings were performed during sinus rhythm.Results:The MAP recordings were obtained from both right atrium and left ventricle in 9 pigs, while the right ventricle was mapped during the same procedure in 2. The MAP electrograms were recorded from both right and left atrium via a patent foramen ovale in 1 pig. Totally, the right atrium was mapped in all the 10 pigs, right ventricle in 2, left atrium in 1 and left ventricle in 9. The MAP electrograms were recorded from 733 sites of right atrium, 179 of right ventricle, 63 of left atrium and 517 of left ventricle. There were 62% of right and 54% left atrial MAPamp satisfied the earlier defined criteria of acceptable MAP, i.e., the MAPamp ≥ 3 mV in atrium, while 32% of right and 38% of left ventricular MAPamp were ≥ 10 mV. The mean MAPamp was 5.7±3.1 mV in right atrium, 12.4±2.5 mV in right ventricle, 4.5±1.9 mV in left atrium and 13.8±4 mV in left ventricle. The local activation was more distinctly and easily defined using MAP recordings with the computer-assisted manual determination, so were the end-of-repolarization points. The global activation and repolarization sequence and MAP duration distribution were constructed in all the pigs both in atrium and in ventricle. The activation sequence both in atrium and ventricle could be determined in all pigs three-dimensionally. In the right atrium two preferential inter-nodal conductions were evident, along the crista terminalis and atrial septum from the sinus node area down to the atrioventricular node. Two main connections, Bachman’s bundle and coronary sinus region, constitute the electrophysiologic pathways for right to left atria activation during sinus rhythm. The earliest ventricular activation was located at the high left ventricular septum and followed by radial activation sequence in both ventricles. The posterior base segments of left and right ventricle were activated latest. In the 4 pigs whose chest was opened after sacrifice, no visual detectable injury or bleeding was found in the endocardium and valvular structure. No perforation and no epicardial effusion were observed either.Conclusion: MAP electrograms recorded using the modified platinum catheter were associated with a stable baseline and higher amplitude. MAP recording in difficult areas in all the four chambers of the swine heart was facilitated by the modification of the tip electrode. The construction of the global myocardial activation and repolarization sequence is feasible using the electroanatomical mapping system and MAP recording technique via the modified catheter. The ability to combine MAP recording and spatial information provides a unique tool for both research and clinical electrophysiology.

Semi-Direct Visual Odometry and Mapping System with RGB-D Camera

In this paper a semi-direct visual odometry and mapping system is proposed with a RGB-D camera,which combines the merits of both feature based and direct based methods.The presented system directly estimates the camera motion of two consecutive RGB-D frames by minimizing the photometric error.To permit outliers and noise,a robust sensor model built upon the t-distribution and an error function mixing depth and photometric errors are used to enhance the accuracy and robustness.Local graph optimization based on key frames is used to reduce the accumulative error and refine the local map.The loop closure detection method,which combines the appearance similarity method and spatial location constraints method,increases the speed of detection.Experimental results demonstrate that the proposed approach achieves higher accuracy on the motion estimation and environment reconstruction compared to the other state-of-the-art methods. Moreover,the proposed approach works in real-time on a laptop without a GPU,which makes it attractive for robots equipped with limited computational resources.

INVARIANT MANIFOLDS AND THEIR STABILITY IN A THREE－DIMENSIONAL MEASURE－PRESERVING MAPPING SYSTEMS

In the paper researches on a three-dimensional measure-preserving mappingsystem are made,which is the three-dimensional extension of the Keplerian mapping.With formal series method the expressions of the invariant curves and invarianttori are obtained,Finally the stability of these in variant manifolds is also discussed.

Design and Realization of MapSUV Rural Land Surveying Palm Mapping System

The original surveying tools and methods are backward and low efficient and they will also generate lots of errors in the National secondary land surveying. MapSUV rural land surveying palm mapping system (MapSUV palm mapping system) based on 3S techniques, combines MapGIS rural land surveying database management system. It supports the spatial location information collection and attributes data entry. By combining with GPS receiver, it ensures high accuracy in small volume, which greatly facilitates land surveying. This paper main researched system structure, function module design and key techniques. It introduced the practical process of map spot attribute checking and map spot boundary. Then it gave the application assessment. The results shows that this system greatly improves the work efficiency of outdoor surveying and shorten the time of land surveying, database build and updating.

3-79 Single Event Effect Mapping System at the IMP Micro-beam

The micro-beam is a beam of micrometer or sub-micrometer dimension, which allows precise defined quantitiesof ions to be introduced at precisely defined location. It has been a powerful tool for single event effects (SEE)study. At the IMP micro-beam facility, we have preliminarily built a SEE mapping system to study the microscopicsensitive areas of SEEs on integrated chips.In order to map the SEE distribution with the ion irradiation, the SEE event signal (E) from the device undertest is detected by the analog input of the SEE mapping system; through the SEE mapping software control, thebeam is scanned with the magnetic scan coil of the microbeam facility and the beam position of the scan coil ofthe microbeam facility is used to register the SEE position (X, Y ); Finally, the SEE distribution is drew with apseudo-color bit image online using (NE, X, Y ), where NE is the number of occurrence of SEE type E at beamposition (X, Y ). The input of the SEE mapping system can support simultaneously detection of up to three SEEsignals.

Mapping upland crop–rice cropping systems for targeted sustainable intensification in South China

Upland crop-rice cropping systems(UCR)facilitate sustainable agricultural intensification.Accurate UCR cultivation mapping is needed to ensure food security,sustainable water management,and rural revitalization.However,datasets describing cropping systems are limited in spatial coverage and crop types.Mapping UCR is more challenging than crop identification and most existing approaches rely heavily on accurate phenology calendars and representative training samples,which limits its applications over large regions.We describe a novel algorithm(RRSS)for automatic mapping of upland crop-rice cropping systems using Sentinel-1 Synthetic Aperture Radar(SAR)and Sentinel-2 Multispectral Instrument(MSI)data.One indicator,the VV backscatter range,was proposed to discriminate UCR and another two indicators were designed by coupling greenness and pigment indices to further discriminate tobacco or oilseed UCR.The RRSS algorithm was applied to South China characterized by complex smallholder rice cropping systems and diverse topographic conditions.This study developed 10-m UCR maps of a major rice bowl in South China,the Xiang-Gan-Min(XGM)region.The performance of the RRSS algorithm was validated based on 5197 ground-truth reference sites,with an overall accuracy of 91.92%.There were7348 km^(2) areas of UCR,roughly one-half of them located in plains.The UCR was represented mainly by oilseed-UCR and tobacco-UCR,which contributed respectively 69%and 15%of UCR area.UCR patterns accounted for only one-tenth of rice production,which can be tripled by intensification from single rice cropping.Application to complex and fragmented subtropical regions suggested the spatiotemporal robustness of the RRSS algorithm,which could be further applied to generate 10-m UCR datasets for application at national or global scales.

Mapping ecosystem services in urban and peri-urban areas.A systematic review

Urban and peri-urban ecosystems are subjected to an intense impact.The demand for ecosystem services(ES)is higher in these areas.Nevertheless,despite the anthropogenic pressures,urban and peri-urban ecosystems supply important ES.Mapping is a crucial exercise to understand ES dynamics in these environments better.This work aims to systematically review mapping ES in urban and peri-urban areas studies,following the Preferred Reporting Items for Systematic Reviews and Meta-alpha Methods.A total of 207 studies were selected.The results show increased work between 2011 and 2023,mainly conducted in Europe and China.Most work were developed in urban areas and did not follow an established ES classification.Most studies focused on the ES supply dimension,the regulation and maintenance section.Regarding provisioning ES,most studies focused on Cultivating terrestrial plants for nutrition,regulating and maintainin g Atmospheric composition and conditions,and for cultural ES on Physical and experiential interactions with the natural environment.Quantitative methods were mostly applied following Indicator-based(secondary data:biophysical,socio-economic)models.Very few work validated the outputs.Several studies forecasted ES,primarily based on land use changes using CA-Markov approaches.This study provides an overview of the most mapped urban and peri-urban ES globally,the areas where more studies need to be conducted,and the methods developed.

磁共振T1rho序列、T2 mapping技术在膝关节早期软骨退变早期诊断中的评估价值

目的探讨磁共振T1rho序列、T2 mapping技术在膝关节早期软骨退变早期诊断中的评估价值。方法选取2020年1月至2022年11月在我院治疗的110例膝关节早期软骨退变患者(观察组),按照疾病严重程度分为轻度退变组及重度退变组,另选取同期在我院进行体检的64例健康者为对照组,受试者均行磁共振T1rho序列、T2 mapping技术扫描,测量受试者T2值及T1ρ值,探讨磁共振T1rho序列、T2 mapping技术在膝关节早期软骨退变早期诊断中的评估价值。结果观察组股骨外侧面、股骨内侧面、胫骨外侧面、胫骨内侧面、髋骨面T2值均明显高于对照组(P<0.05),重度退变亚组患者股骨外侧面、股骨内侧面、胫骨外侧面、胫骨内侧面、髋骨面T2值显著高于轻度退变者(P<0.05);观察组股骨内踝负重区、股骨内踝非负重区、股骨外踝负重区、股骨外踝非负重区、胫骨外侧平台区、胫骨内侧平台区、髌后软骨区磁共振T1ρ值明显高于对照组(P<0.05),重度退变亚组患者股骨内踝负重区、股骨内踝非负重区、股骨外踝负重区、股骨外踝非负重区、胫骨外侧平台区、胫骨内侧平台区、髌后软骨区磁共振T1ρ值明显高于轻度退变亚组患者(P<0.05);磁共振T1rho序列在膝关节早期软骨退变中早期诊断及严重程度评估中的的诊断ROC值及特异度明显高于T2 mapping技术(P<0.05),但后者具有更高的敏感度(P<0.05)。结论磁共振T1rho序列、T2 mapping技术均能有效反映膝关节早期软骨退变中软骨组织学成分变化情况,还可为膝关节软骨退变严重程度评估提供客观依据,二者具有一定互补价值。

MR T2^(*)mapping成像技术定量评价腰椎小关节炎软骨损伤

背景:腰椎小关节炎是引起下腰痛的一个主要原因,目前主要依靠MRI进行初步定性诊断,但仍有一定漏诊、误诊的概率发生,因此MR T2^(*)mapping成像技术有望成为定量检查腰椎小关节炎软骨损伤的重要检测手段。目的:探讨MR T2^(*)mapping成像技术在定量分析腰椎小关节炎软骨损伤退变中的应用价值。方法:收集南京医科大学第四附属医院2020年4月至2022年3月门诊或住院合并下腰痛共110例患者,设为病例组;同时招募无症状志愿者80例,设为对照组。对所有纳入对象L1-S1的小关节行3.0 T MR扫描,获取T2^(*)mapping横断位图像和T2WI图像,分别对所有小关节软骨进行Weishaupt分级及T2^(*)值测量,收集数据并行统计学分析。不同小关节Weishaupt分级之间小关节软骨T2^(*)值比较采用单因素方差分析。结果与结论:①经统计分析发现,病例组腰椎小关节软骨T2^(*)值(17.6±1.5)ms明显较对照组(21.4±1.3)ms降低,差异有显著性意义(P<0.05);②在病例组中,随着腰椎小关节Weishaupt分级增加,小关节软骨T2^(*)值也呈逐渐下降趋势,且这种差异有显著性意义(P<0.05);③提示T2^(*)mapping能够较好地显示腰椎小关节软骨损伤的早期病理变化,腰椎小关节软骨的T2^(*)值能够定量评估腰椎小关节的软骨损伤程度;T2^(*)mapping成像技术能为影像学诊断腰椎小关节炎软骨早期损伤提供很好的理论依据,具有重要的临床应用价值。

DWI联合T2 mapping序列鉴别前列腺癌与前列腺增生价值评估

目的探讨扩散加权成像(diffusion-weighted imaging,DWI)联合T2 mapping序列鉴别前列腺癌(prostate cancer,PCa)与前列腺增生(benign prostatic hyperplasia,BPH)的价值。材料与方法回顾性分析本院行3.0 T MRI检查且经病理证实的56例PCa患者及40例BPH患者资料。扫描序列包括T1WI、T2WI、DWI及T2 mapping序列。两名观察者分别测量两组病灶的表观扩散系数(apparent diffusion coefficient,ADC)值及T2值。采用组内相关系数(intra-class correlation coefficient,ICC)评估两名观察者测得参数值的一致性。采用独立样本t检验或Mann-Whitney U检验分析两组病例间ADC值及T2值的差异。Logistic回归用于分析差异具有统计学意义的参数及其与基线资料联合的诊断模型。采用受试者工作特征(receiver operating characteristic,ROC)曲线评估有差异参数及联合模型的诊断效能。采用DeLong检验比较ROC曲线下面积差异。采用Spearman相关系数分析ADC值与T2值相关性。结果两名观察者测量值一致性好(ICC>0.75)。PCa组的ADC值及T2值分别低于BPH组,差异具有统计学意义(P<0.01)。ADC值、T2值、ADC-T2及ADC-T2-年龄-总前列腺特异性抗原(total prostate specific antigen,TPSA)联合鉴别PCa与BPH的AUC值分别为0.843、0.830、0.896及0.927。DeLong检验显示ADC值与ADC-T2联合,ADC值、T2值、ADC-T2模型与ADC-T2-年龄-TPSA联合模型的ROC差异存在统计学意义(P<0.05)。ADC值与T2值呈正相关(r=0.331,P<0.01)。结论DWI及T2 mapping序列在鉴别PCa与BPH方面具有较好的价值,并且两序列联合临床指标时诊断效能提升,可为临床无创诊断PCa及BPH提供很好的指导意义。

磁共振集合序列与T2mapping序列在慢性冈上肌腱炎定量评估中的价值研究

目的探讨磁共振集合序列(magnetic resonance image compilation,MAGiC)与T2mapping序列在慢性冈上肌腱炎中的诊断价值,并比较两者在冈上肌腱扫描中的图像质量,以及两序列的T2值在冈上肌腱不同亚区的相关性。材料与方法回顾性收集2022年10月至2024年1月本院慢性冈上肌腱炎的患者30例(肌腱炎组)及健康体检者26例(对照组),均进行了常规MRI、T2mapping序列和MAGiC序列扫描。由两名放射科医生根据冈上肌腱走行将其分为外侧、中间、内侧亚区,并在MAGiC序列及T2mapping序列上测量不同亚区定量值。对比T2mapping序列第一回波图像与MAGiC T2WI的图像质量,并测量信号噪声比(signal to noise ratio,SNR)、对比噪声比(contrast to noise ratio,CNR)。采用Mann-Whitney U检验分析肌腱炎组与对照组在不同亚区各定量参数的差异以及两序列的图像质量。绘制受试者工作特征(receiver operating characteristic,ROC)曲线并计算曲线下面积(area under the curve,AUC),评价其对慢性冈上肌腱炎的诊断效能。对T2mapping序列与MAGiC序列测得的不同亚区T2值采用Pearson相关分析评价相关性。结果MAGiC序列重建图像MAGiC T2WI与T2mapping序列第一回波图像质量主观评分差异无统计学意义(Z=-1.535,P>0.05);MAGiC T2WI图像的CNR高于T2mapping序列第一回波图像[15.45(12.76,20.46)vs.9.94(8.74,12.23)],差异有统计学意义(Z=-2.473,P<0.001),而MAGiC T2WI图像的SNR低于T2mapping序列第一回波图像[2.49(2.16,2.71)vs.5.82(5.16,7.44)],差异有统计学意义(Z=-0.609,P<0.001);MAGiC序列与T2mapping序列的T2值在肌腱炎组外侧亚区、内侧亚区均高于对照组,差异有统计学意义(P<0.05);MAGiC序列的T1值在肌腱炎组外侧亚区高于对照组,差异有统计学意义(P<0.05)。外侧亚区T2mapping T2值、MAGiC T1、T2值诊断冈上肌腱炎的AUC分别为0.822、0.663、0.799;内侧亚区T2mapping T2值、MAGiC T2值诊断冈上肌腱炎的AUC分别为0.711、0.762。MAGiC序列T2值与T2mapping T2值在冈上肌腱外侧亚区、中间亚区、内侧亚区呈正相关(相关系数分别为0.736、0.437、0.464)。结论MAGiC定量图谱的T1、T2值与T2mapping T2值能够有效评估冈上肌腱内部成分的异质性,反映慢性冈上肌腱炎与正常肌腱内部成分的差异及肌腱自身的区域性差异,可为临床对冈上肌腱变性提供量化的客观依据。

健康人膝关节股骨内侧髁软骨的T_(2) mapping研究

目的应用T_(2) mapping技术测量健康人膝关节股骨内侧髁负重区与非负重区各层软骨T_(2)值并分析其差异,探讨膝关节软骨分层、分区域MRI定量研究的价值。方法前瞻性纳入22名健康志愿者,其中男、女各11名,平均年龄(27.05±1.05)岁。共纳入38个膝关节,左膝20个,右膝18个。对志愿者行膝关节MRI矢状面T_(2) mapping检查,选取膝关节股骨内侧髁负重区35个、非负重区37个,并测量完整关节软骨上最厚处的T_(2)值。采用独立样本t检验和方差分析分别比较股骨内侧髁负重区与非负重区各层软骨的T_(2)值及各区域内关节软骨浅、中、深层的T_(2)值。结果股骨内侧髁负重区及非负重区的软骨各层T_(2)值由大到小依次为浅层、中层、深层,除非负重区软骨浅层与中层间的T_(2)值差异无统计学意义(P>0.05),余各2层间T_(2)值差异均有统计学意义(均P<0.05);负重区软骨中层、深层T_(2)值均小于非负重区(均P<0.05),负重区与非负重区软骨浅层的T_(2)值差异无统计学意义(P>0.05)。结论健康人膝关节软骨依据T_(2)值差异可分为3层且负重区软骨T_(2)值更低,对膝关节软骨分层、分区域研究具有可行性。

T_(2)mapping技术在鉴别直肠黏液腺癌和非黏液腺癌中的价值

目的:探讨T_(2)mapping技术对直肠黏液腺癌和非黏液腺癌的鉴别诊断价值。方法:前瞻性纳入直肠癌患者69例,其中黏液腺癌9例,非黏液腺癌60例,所有患者均行盆腔MRI检查,扫描序列包括T_(2)mapping及DWI序列。由2位经验丰富的放射科医师独立测量病灶的T_(2)值及ADC值,采用独立样本t检验或Mann-Whitney U检验比较不同病理类型肿瘤各参数值的差异。采用ROC曲线和DeLong检验分析T_(2)值、ADC值及两者联合的诊断效能。结果:直肠黏液腺癌的T_(2)值及ADC值均高于非黏液腺癌,差异均有统计学意义(均P<0.05)。T_(2)值、ADC值及联合指标(T_(2)值+ADC值)鉴别直肠黏液腺癌和非黏液腺癌的AUC分别为0.96、0.81和0.97,T_(2)值与ADC值的差异及联合指标与ADC值的差异均有统计学意义(均P<0.05)。结论:T_(2)mapping对直肠黏液腺癌与非黏液腺癌的鉴别诊断效能优于DWI,DWI联合T_(2)mapping可显著提高对直肠黏液腺癌与非黏液腺癌的鉴别诊断准确率。

T1 mapping技术及在评估心肌纤维化中的应用进展

T1 mapping技术是近年来应用较为广泛的MRI新技术,其通过量化心肌组织的T1值和细胞外容积分数,可对导致心肌纤维化的疾病进行评估。本文综述T1 mapping的基本原理、扫描序列及在导致心肌纤维化的疾病中的应用,主要包括心梗、肥厚型心肌病、扩张型心肌病、先天性心脏病、主动脉狭窄、高血压性心脏病、糖尿病心肌病、尿毒症性心肌病、射血分数保留型心衰、心脏移植等。

MR弹性成像与钆塞酸二钠增强T1 mapping定量评估兔肝纤维化的对比研究

目的评价MR弹性成像(magnetic resonance elastography,MRE)、钆塞酸二钠(gadolinium ethoxybenzyl diethyle netriamine pentaacetic acid,Gd-EOB-DTPA)增强T1 mapping在肝纤维化(liver fibrosis,LF)早期定量的价值。材料与方法实验材料为新西兰大白兔(共120只),分为正常对照组(n=20)与肝纤维化组[LF组,50%四氯化碳(carbon tetrachloride,CCL_(4))油溶液模型,n=100],分别在第4、5、6、15周末取5只对照组与25只LF组兔行MRI肝脏轴位T1WI、MRE及Gd-EOB-DTPA增强T1 mapping扫描,测量肝脏弹性硬度(liver stiffness,LS)、平扫T1弛豫时间(T1_(native))及Gd-EOB-DTPA增强T1 mapping扫描20 min后T1弛豫时间(T1_(20min)),计算T1弛豫时间减少率(ΔT1_(20min))及1/T1弛豫时间增加值(ΔR1_(20min));采用Scheuer评分系统进行LF病理学分期,单因素方差分析对比各定量参数与LF分期间的差异,Spearman相关性分析比较各定量参数与LF病理分期相关性,受试者工作特征(receiver operating characteristic,ROC)曲线评估各定量参数对LF分期诊断效能。结果共纳入96只活兔模型,病理学评分:F0期15只、F1期22只、F2期22只、F3期18只、F4期19只。LS、T1_(native)、T1_(20min)、ΔT1_(20min)、ΔR1_(20min)于LF各期间差异均有统计学意义(P<0.05)。LS、T1_(native)、T1_(20min)、ΔT1_(20min)、ΔR1_(20min)均与LF分期相关(r=0.935、0.559、0.770、-0.418、-0.686,P<0.001)。F0 vs.F1~F4、F0 vs.F1~F2、F0 vs.F3~F4、F1~F2 vs.F3~F4的LS值ROC曲线下面积(area under the curve,AUC)分别为0.988、0.979、1.000、0.995,T1_(20min)值AUC分别为0.914、0.852、0.987、0.896。结论在评估LF早期诊断中,MRE及Gd-EOB-DTPA增强T1 mapping成像均显示出较好的诊断价值,MRE优于Gd-EOB-DTPA增强T1 mapping。

MR超短回波PETRA-FS、T2*Mapping序列评估健康青年膝关节软骨的应用价值

目的:运用MR超短回波时间成像径向采集逐点编码时间缩减联合脂肪抑制(pointwise encoding time reduction with radial acquisition combined fat suppression, PETRA-FS)序列及T2*mapping序列,探讨其在健康青年患者膝关节MR中的应用价值。方法:收集自2021年8月至2021年10月于青岛大学附属医院接受超短回波时间成像PETRA-FS序列、T2*mapping及FS FSE PDWI序列扫描的健康青年患者22名,将健康青年膝关节软骨划分为15个小亚区,共获取645个亚区,另将其分为承重区和非承重区,定量记录每个亚区软骨厚度和T2*值,按性别分组,应用独立样本t检验,比较各亚区合并后大部位的厚度及T2*值差异,总结膝关节整体软骨分布特点。结果:(1) 健康青年膝关节软骨厚度从高到低依次为髌软骨(3.74 mm)、股骨外侧髁(1.94 mm)、股骨外侧滑车(1.71 mm)、股骨内侧髁(1.46 mm)、胫骨内侧髁(1.21 mm)、胫骨外侧髁(1.11 mm)。(2) 健康青年男、女之间膝关节大部区域(除股骨内侧髁、胫骨内侧髁之外)的软骨厚度差异具有统计学意义(P 0.05);承重区和非承重区的T2*值差异具有统计学意义(P < 0.05)。结论:在健康青年中,性别可能是影响膝关节软骨厚度的重要因素,而软骨的T2*值可能受性别影响较小。本组的研究表明:T2*mapping和超短回波PETRA-FS序列能够较好的评价正常软骨并为其早期异常改变提供正常影像学参照。

Identification of candidate genes for early-maturity traits by combining BSA-seq and QTL mapping in upland cotton(Gossypium hirsutum L.)

Cotton breeding for the development of early-maturing varieties is an effective way to improve multiple cropping indexes and alleviate the conflict between grains and cotton in the cultivated fields in China.In the present study,we aimed to identify upland cotton quantitative trait loci(QTLs)and candidate genes related to early-maturity traits,including whole growth period(WGP),flowering timing(FT),node of the first fruiting branch(NFFB),height of the node of the first fruiting branch(HNFFB),and plant height(PH).An early-maturing variety,CCRI50,and a latematuring variety,Guoxinmian 11,were crossed to obtain biparental populations.These populations were used to map QTLs for the early-maturity traits for two years(2020 and 2021).With BSA-seq analysis based on the data of population 2020,the candidate regions related to early maturity were found to be located on chromosome D03.We then developed 22 polymorphic insertions or deletions(InDel)markers to further narrow down the candidate regions,resulting in the detection of five and four QTLs in the 2020 and 2021 populations,respectively.According to the results of QTL mapping,two candidate regions(InDel_G286-InDel_G144 and InDel_G24-InDel_G43)were detected.In these regions,three genes(GH_D03G0451,GH_D03G0649,and GH_D03G1180)have nonsynonymous mutations in their exons and one gene(GH_D03G0450)has SNP variations in the upstream sequence between CCRI50 and Guoxinmian 11.These four genes also showed dominant expression in the floral organs.The expression levels of GH_D03G0451,GH_D03G0649 and GH_D03G1180 were significantly higher in CCRI50 than in Guoxinmian 11 during the bud differentiation stages,while GH_D03G0450 showed the opposite trend.Further functional verification of GH_D03G0451 indicated that the GH_D03G0451-silenced plants showed a delay in the flowering time.The results suggest that these are the candidate genes for cotton early maturity,and they may be used for breeding early-maturity cotton varieties.