Determination of volumetric elastic moduli of plant leaf cells based on pressure-volume curves

Volumetric elastic modulus （VEM） is an important parameter in biophysics and biomechanics of plants for in particular understanding cell growth. This paper proposes a new relation that can be used for precisely determining VEM. With the aid of this relation, it shows that the exponential approximation of the pressure-volume relationship adopted in most of the literatures in this field may lead to serious errors on VEM.

Discrimination of Structural Isomers of Aromatic Compounds with EI Mass Spectra and Their Ionization Efficiency Curves of Dehydrogenated Fragment Ions

The mechanism of ionization and fragmentation for terphenyl (diphenylbenzene) with three structural ring isomers (ortho-, meta- and para-), and stilbene (1,2-diphenylethylene) with two geometrical isomers (trans- and cis-) by EI mass spectrometry and ionization efficiency curves are investigation.

Straw return increases crop grain yields and K-use efficiency under a maize-rice cropping system

Straw return is an effective way to improve crop grain yield and potassium(K)use efficiency by increasing soil K content.However,the effects of straw return on soil K supplying capacity,replacement of K fertilizer,and K-use efficiency under maize(Zea mays L.)–rice(Oryza sativa L.)cropping systems are little studied.A two-year field experiment was conducted to determine the physiological determinants of K-use efficiency under straw return with four K fertilization rates.Sr33(straw returned plus 33%of K fertilizer applied)and Sr67(straw returned plus 67%of K fertilizer applied)increased annual crop yields by 1.5%and 3.2%and increased agronomic K-use efficiency by respectively 2.9 and 1.3-fold on average in the two years,compared with the conventional practice S0K100(no straw returned plus normal amounts of K fertilizer applied).The Sr33 and Sr67 treatments resulted in significantly greater equilibrium K concentration ratios(CR0 K)and specifically exchangeable K(KX)values according to quantity/intensity(Q/I)relationship analyses,indicating improvement of the potential soil K supply capacity.However,the Sr67 better maintained the soil exchangeable K level and K balance.The results suggested that K released from maize and rice straw can replace about half of chemical K fertilizer,depending on the available K content in maize–rice cropping system production.

Optimal Weights in Nonparametric Analysis of Clustered ROC Curve Data

In diagnostic trials, clustered data are obtained when several subunits of the same patient are observed. Within-cluster correlations need to be taken into account when analyzing such clustered data. A nonparametric method has been proposed by Obuchowski (1997) to estimate the Receiver Operating Characteristic curve area (AUC) for such clustered data. However, Obuchowski’s estimator gives equal weight to all pairwise rankings within and between cluster. In this paper, we modify Obuchowski’s estimate by allowing weights for the pairwise rankings vary across clusters. We consider the optimal weights for estimating one AUC as well as two AUCs’ difference. Our results in this paper show that the optimal weights depends on not only the within-patient correlation but also the proportion of patients that have both unaffected and affected units. More importantly, we show that the loss of efficiency using equal weight instead of our optimal weights can be severe when there is a large within-cluster correlation and the proportion of patients that have both unaffected and affected units is small.

Classification Study on Relative Permeability Curves

The classification method of relative permeability curves is rarely reported, when relative permeability curves are applied;if the multiple relative permeability curves are normalized directly, but not classified, the calculated result maybe cause a large error. For example, the relationship curve between oil displacement efficiency and water cut, which derived from the relative permeability curve in LD oilfield is uncertain in the shape of low water cut stage. If being directly normalized, the result of the interpretation of the water flooded zone is very high. In this study, two problems were solved: 1) The mathematical equation of the relationship between oil displacement efficiency and water cut was deduced, and repaired the lost data of oil displacement efficiency and water cut curve, which solve the problem of uncertain curve shape. After analysis, the reason why the curve is not available is that relative permeability curves are not classified and optimized;2) Two kinds of classification and evaluation methods of relative permeability curve were put forward, the direct evaluation method and the analogy method;it can get the typical relative permeability curve by identifying abnormal curve.

From Pressure-Volume Relationship to Volume-Energy Relationship: A Thermo-Statistical Model for Alveolar Micromechanics

The connective tissue fiber system and the surfactant system are essential and interdependent components of lung elasticity. Despite considerable efforts over the last decades, we are still far from understanding the quantitative roles of either the connective tissue fiber or the surfactant systems. Through thermo-statistic considerations of alveolar micromechanics, the author introduced a thermo-statistic state function “entropy” to analyze the elastic property of pulmonary parenchyma based on the origami model of alveolar polyhedron. By use of the entropy for alveolar micromechanics, from the logistic equation for the static pressure (P)-volume (V) curves including parameters a, b, c, and k (V - a = b/[1+ exp{-k (P - c)}]), a set of equations was obtained to define the internal energy of lungs (UL) and its corresponding lung volume (VL). Then, by use of parameters a, b, c, and k, an individual volume-internal energy (VL - UL) diagram was constructed from reported data in patients on mechanical ventilation. Each VL - UL diagram constructed was discussed that its minimal value Uo = c (a + b/2) and its shape parameter b/k represent quantitatively the energy of tissue force and the energy of surface force. Furthermore, by use of the VL - UL relationship, the hysteresis of lungs estimated by entropy production was discussed as dependent on the difference in the number of contributing pulmonary lobules. That is, entropy production might be a novel quantitative indicator to estimate the dynamics of the bronchial tree. These values obtained by combinations of parameters of the logistic P-V curve seem useful indicators to optimize setting a mechanical ventilator. Thus, it is necessary to develop easy tools for fitting the individual sigmoid pressure-volume curve measured in the intensive care unit to the logistic equation.

Analysis of the generation mechanism of the S-shaped J–V curves of MoS_(2)/Si-based solar cells

Amorphous–microcrystalline MoS_(2)thin films are fabricated using the sol-gel method to produce MoS_(2)/Si-based solar cells. The generation mechanisms of the S-shaped current density–voltage(J–V) curves of the solar cells are analyzed. To improve the performance of the solar cells and address the problem of the S-shaped J–V curve, a MoS_(2)film and a p^(+) layer are introduced into the front and back interfaces of the solar cell, respectively, which leads to the formation of a p–n junction between the p-Si and the MoS_(2)film as well as ohmic contacts between the MoS_(2)film and the ITO, improving the S-shaped J–V curve. As a result of the high doping characteristics and the high work function of the p^(+) layer, a high–low junction is formed between the p;and p layers along with ohmic contacts between the p;layer and the Ag electrode. Consequently,the S-shaped J–V curve is eliminated, and a significantly higher current density is achieved at a high voltage. The device exhibits ideal p–n junction rectification characteristics and achieves a high power-conversion efficiency(CE) of 7.55%. The findings of this study may improve the application of MoS_(2)thin films in silicon-based solar cells, which are expected to be widely used in various silicon-based electronic and optical devices.

Phosphorus Use Efficiency of Safflower （Carthamus tinctorius L.） and Sunflower （Helianthus annuus L.） Studied in Nutrient Solution

Safflower represents an important oil crop internationally and may have a production potential under low input conditions, but its putatively high phosphorous use efficiency is not sustained. This study aims to directly compare safflower with sunflower in terms of phosphorus use efficiency in nutrient solution under controlled conditions. Growth of both species responded strongly to increasing P supply. Safflower recovers less proportion of added P than sunflower. External P requirement （（g P supply （100 g dry matter （DM） produced）~） was higher in safflower than sunflower. The efficiency of the crops for DM production based on accumulated P （mg P potl, efficiency ratio）, and P concentration in DM （（mg P （g DM）＇I）, utilization index） were interpreted using Michaelis-Menten kinetics as growth response curves. Accordingly, Km constant was lower in sunflower compared to safflower in terms of utilization index, but both were similar in terms of efficiency ratio. High Km constant in safflower in terms of utilization index indicates the high P concentration in tissues to produce 50% of potential maximum DM, consequently less efficient crop. Utilization efficiency contributed more than uptake efficiency in overall PUE in the efficient cultivar and could be the cause of its superiority in PUE. It can be concluded that safflower has a high requirement for P with respect to growth, sunflower is more efficient in terms of uptake and utilization of P at optimal and sub-optimal P supplies indicating that safflower can not be considered a low nutrient input crop compared to sunflower with respect to phosphorus.

Monotricat, Innovative Displacement Hull High Hydrodynamic Efficiency and Energy Recovery, Navigating at Speeds of Planing Hulls on Spray Self-produced

The need to have naval units ever faster pushed the ship design to design hull shapes with increasingly higher performance thanks to the use of lightweight materials such as aluminum, and more powerful engines, etc., but without substantially modifying the traditional forms of hull. The hull patented Monotricat high hydrodynamic efficiency and energy saving it represents an evolution of the traditional architectures of the hulls, as its shape is adapted to recover wave formation engendered from the bow and sprays associated with it so as to reduce the resistance to the benefit of the speed, and navigating in displacement at speeds of planing hulls with an efficiency of about 20%. The patented hull Monotricat represents the overcoming of distinction between displacement and planing hulls, because, unlike previous solutions, the hull conventionally called Monotricat is the first displacement hull that can navigate at both displacement and planning speeds, with a resistance curve almost straight, maintaining the characteristics of a displacement hull, since it combines the characteristics of displacement and planning hull. It presents an innovative architecture that could be defined as a hybrid between a monohull and catamaran, navigating on spray self-produced. The combination of these three types of naval hulls allows it to ensure： safety, comfort navigation, best seakeeping and maneuverability in restricted waters, stability, reduction of resistance to motion, cost management, regularity on the routes even in adverse weather-sea. These characteristics of the hull have been studied, tested and validated by leading research institutes and universities with more ameliorative results in each subsequent experimentation, reported in the present work, which demonstrated a greater hydrodynamic efficiency compared to conventional hulls of 20%.

A mathematical method to calculate efficiency of BF_3 detectors

In order to calculate absolute efficiency of the BF3 detector, MCNP/4C code is applied to calculate relative efficiency of the BF3 detector first, and then absolute efficiency is figured out through mathematical techniques. Finally an energy response curve of the BF3 detector for 1~20 MeV neutrons is derived. It turns out that efficiency of BF3 detector are relatively uniform for 2~16 MeV neutrons.

PASCO-Tracker实验系统的搭建及其对热机效率的测量

为使热机p-V图线的测量和由图线计算热机效率的整体过程可成为大学物理实验中易于操作的一部分,笔者首先搭建了PASCO-Tracker实验系统,然后在两种高温热源温度下,通过该系统分别实践了热机工作中p-t、V-t关系图线的测量,并在此基础上得到了p-V图线,在拟合出p-V关系函数后,通过原理公式的计算得到了热机效率与高温热源温度及气缸内装入的钢丝质量间的关系。测量结果表明,压强、体积的周期均随钢丝质量的增加而减小,效率随钢丝质量的增加而增加,二者具有非线性关系。热机效率随高温热源温度的增加而增加。本实验系统可用于演示热机工作过程的实时监控和热机效率的测量与计算。

农业生产性服务与农业绿色生产效率——基于环境规制的调节效应研究

基于2010-2021年中国31个省区市面板数据,实证分析农业生产性服务对农业绿色生产效率的影响,探讨环境规制在农业生产性服务与农业绿色生产效率之间所起的调节作用。研究结果表明:农业生产性服务与农业绿色生产效率之间存在显著的U型关系;灌溉设施水平和农业规模化水平对农业绿色生产效率发挥正向效应,收入分配和产业结构会抑制农业绿色生产效率提升;农业生产性服务对农业绿色生产效率的作用效果具有地区异质性,U型关系在中部地区仍旧成立;环境规制强度的提高使U型曲线拐点右移且形状变平缓,具有显著的调节效应。

不同氮效率春玉米品种临界氮浓度稀释曲线建立与验证

采用田间定位试验,以山西省晋中地区春玉米各生育时期地上部干物质量与植株氮浓度的变化规律,建立春玉米临界氮浓度稀释曲线模型,为实现春玉米绿色增产与氮素管理提供理论依据。本研究以玉米品种‘郑单958’和‘大丰26’为试验材料,设4个施氮量处理:0 kg(N)∙hm^(−2)(N0)、120 kg(N)∙hm^(−2)(N120)、240 kg(N)∙hm^(−2)(N240)和360 kg(N)∙hm^(−2)(N360),于2014—2016年在山西农业大学东阳试验基地开展3年定位施氮试验,在春玉米拔节期(V6)、抽雄期(VT)、灌浆期(R2)和成熟期(R6)采集植株样品,分析两个春玉米品种在不同施氮量处理下地上部干物质量、籽粒产量(以下简称“产量”)和各生育时期植株氮浓度,以不同生育时期干物质累积量和植株氮浓度,建立并验证两个春玉米品种的临界氮浓度稀释曲线模型。结果表明,‘郑单958’氮素利用率高于‘大丰26’。两个春玉米品种在适宜施氮量条件下,各生育时期地上部干物质量和产量均随施氮量增加呈增加趋势,地上部干物质量在N240和N360处理间差异不显著,产量在N240处理达最大值;植物氮浓度随施氮量增加而增加,随春玉米生育进程推进与地上部干物质量呈幂指数关系。依据春玉米地上部干物质量(Md)与其对应的植株氮浓度(CN)变化关系,建立两个春玉米品种的临界氮浓度稀释曲线模型:‘郑单958’CN=30.457Md−0.292,‘大丰26’CN=33.249Md−0.333。相比‘大丰26’的模型参数,‘郑单958’的模型参数a降低8.40%,参数b降低12.31%;‘郑单958’和‘大丰26’模型均方根误差(RMSE)分别为1.71 g∙kg^(−1)和1.54 g∙kg^(−1),标准化均方根误差(n-RMSE)分别为9.25%和8.27%,表明模型稳定性较好。氮营养指数在同一生育时期随施氮量增加呈上升趋势,随生育时期推进呈先增加后降低趋势,与各生育时期的相对干物质量呈显著线性相关,与相对产量呈显著的一元二次曲线关系。本研究建立的晋中地区两个春玉米品种临界氮浓度稀释曲线模型及各生育时期氮营养指数,可用于春玉米生育时期营养状况的诊断和评估,结合施氮量与产量的关系,推荐该试验区域‘郑单958’施氮量为189.16~224.08 kg∙hm^(−2),‘大丰26’施氮量为199.72~214.67 kg∙hm^(−2)。

低效井合理捞油周期确定方法研究

低产低效井常规有杆采油方式成本较高,使用提捞采油方式对低产井进行开采具有一定的经济效益。文中基于油井流入动态,结合井筒压力计算方程,建立一套捞油周期数学模型。在研究井筒流入累积液量、生产压差、动液面恢复与生产时间关系的基础上,根据不同动液面上升速率对提捞井进行分类,制定合理提捞周期。并在14口捞油井上进行了生产试验,平均单次作业捞油量增加2.4 t,显著提高了捞油井的生产效率和经济效益。

网织红细胞平均血红蛋白含量在缺铁性贫血及其严重程度的诊断效能分析

目的:评价网织红细胞平均血红蛋白含量(mean reticulated hemoglobin content,Mchr)在诊断缺铁性贫血(iron deficiency anemia,IDA)及其严重程度中的价值。方法:选取2021年1月至2021年12月上海交通大学医学院附属瑞金医院(北部院区)、新华医院和瑞金医院的302例IDA患者,其中轻度贫血118例,中度贫血159例和重度贫血25例,365例非IDA患者(包括地中海贫血、巨细胞性贫血、纯红细胞再生障碍性贫血、溶血性贫血、再生障碍性贫血),以及138名健康体检者。采集所有患者的静脉血样本,检测血红蛋白(hemoglobin,Hb)、红细胞压积(hematocrit,HCT)、Mchr、平均红细胞体积(mean corpuscular volume,MCV)、平均红细胞血红蛋白(mean corpuscular hemoglobin,MCH)、平均红细胞血红蛋白浓度(mean corpuscular hemoglobin concentration,MCHC)、血清铁(serum iron,Fe)、铁饱和度(the saturability of iron,TS)、铁蛋白(Ferritin)和总铁结合力(total iron-binding capacity,TIBC)。比较IDA患者组与非IDA患者组以及IDA不同严重程度之间的Mchr水平,绘制受试者操作特征(Receiver operating characteristic,ROC)曲线,评估Mchr在IDA中的诊断价值。结果:与非IDA组相比,IDA组的Mchr、Hb、MCV、MCH、MCHC、HCT、Fe、TS、Ferritin水平显著降低,而TIBC显著升高,差异均有统计学意义(P<0.05)。IDA组的Mchr与Hb、MCV、MCH、MCHC、HCT、Fe、TS、Ferritin呈正相关,与TIBC呈负相关。轻度、中度、重度IDA患者的Mchr水平依次减低,3组间差异有统计学意义(P<0.05)。ROC曲线分析结果显示,Mchr诊断IDA的最佳临界值为<26.7 pg,诊断灵敏度为80.00%,特异度为93.38%,曲线下面积(the area under the curve,AUC)为0.9338(95%CI为0.9157~0.9518),Mchr+Fe+Ferritin+TIBC联合诊断IDA(各项目的临界值分别为Mchr<26.7pg,Fe<5.7μmol/L,Ferritin<7.1 ng/mL,TIBC>65.8μmol/L)的灵敏度为90.76%,特异度为94.70%,AUC为0.9839(95%CI为0.9772~0.9905)。结论:Mchr可作为诊断筛查IDA及其严重程度的潜在临床指标,其联合铁代谢指标诊断IDA更具有诊断价值,能够为选择是否需要进行侵入性诊断提供有力依据。

膜下滴灌微咸水棉花临界氮稀释曲线模型与氮肥用量推荐

为了优化膜下滴灌微咸水条件下棉花生产氮素管理,该研究于2017—2019年在新疆库尔勒市开展3 a定位施氮试验。以新陆中棉花为试验材料,设置施氮水平0(NF0)、150(NF1)、250(NF2)、300(NF3)、350(NF4)、450(NF5)kg/hm^(2),各试验处理灌水量均为487.5 mm,分析施氮量对棉花地上部干物质量、氮素累积吸收量、产量和氮肥利用效率的影响,构建了膜下滴灌微咸水棉花临界氮浓度稀释曲线模型。结果表明:棉花氮素累积吸收量随生育期进程的推进而增大,棉花临界氮浓度与最大地上部干物质量符合幂函数关系。氮肥农学利用率和表观利用率均与施氮量呈二次多项式关系,氮肥生理利用率和偏生产力均与施氮量呈线性关系。NF1、NF2和NF3处理的氮素营养指数均小于1,表明氮素营养供应不足,棉花生长受到氮素限制。NF4和NF5处理的氮素营养指数接近于1,说明棉花氮素营养状况较好,但NF5产量和氮素利用效率较低,NF4获得最高产量和较高的氮素利用效率。因此,南疆膜下滴灌微咸水棉花生育期推荐施氮量为350 kg/hm^(2)。该研究构建的临界氮浓度稀释曲线模型对田间施氮管理具有重要意义。

径流曲线数模型在湖南省山区小流域的优化与应用

径流曲线数模型(Soil Conservation Service Curve Number Model,简称SCS-CN模型)可以利用降雨资料估算径流,对水资源合理配置和山洪灾害预警具有重要意义,因为其方便计算、参数简单,而被广泛应用。目前标准SCS-CN模型在山区小流域的适用性欠佳,因此需要对模型参数进行优化以提高预测精度。本文以湖南省螺岭桥流域为例,根据实测降雨径流资料优化径流曲线数CN(Curve Number)查算表,并利用步长优化参数算法研究初损率对模型精度的影响,将优化模型的方法应用于湖南省凤凰小流域,验证该优化方法的可靠性。结果分析表明:与标准SCS-CN模型相比,优化后的SCS-CN模型效率系数NSE从0.576提升至0.813,决定系数R^(2)为0.858。将模型优化方法验证于气候地形条件相似的凤凰流域,模型NSE值提高117%。通过预测径流深与实测径流深比较,优化模型模拟精度较为理想,对湖南省山区小流域场次降雨产流预报有一定的参考意义。

Comparison of electrochemical behaviors of Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe and Ti-6Al-4V titanium alloys in NaNO_(3) solution

The Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe(β-CEZ)alloy is considered as a potential structural material in the aviation industry due to its outstanding strength and corrosion resistance.Electrochemical machining(ECM)is an efficient and low-cost technology for manufacturing theβ-CEZ alloy.In ECM,the machining parameter selection and tool design are based on the electrochemical dissolution behavior of the materials.In this study,the electrochemical dissolution behaviors of theβ-CEZ and Ti-6Al-4V(TC4)alloys in NaNO3solution are discussed.The open circuit potential(OCP),Tafel polarization,potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),and current efficiency curves of theβ-CEZ and TC4 alloys are analyzed.The results show that,compared to the TC4 alloy,the passivation film structure is denser and the charge transfer resistance in the dissolution process is greater for theβ-CEZ alloy.Moreover,the dissolved surface morphology of the two titanium-based alloys under different current densities are analyzed.Under low current densities,theβ-CEZ alloy surface comprises dissolution pits and dissolved products,while the TC4 alloy surface comprises a porous honeycomb structure.Under high current densities,the surface waviness of both the alloys improves and the TC4 alloy surface is flatter and smoother than theβ-CEZ alloy surface.Finally,the electrochemical dissolution models ofβ-CEZ and TC4 alloys are proposed.

血清肿瘤标志物联合检测对肺癌诊断及病理分型的价值分析

目的:探讨血清肿瘤标志物单独及联合检测对肺癌诊断及分型的临床价值。方法:将蚌埠医学院第一附属医院呼吸与危重医学科2023年1月至10月收治的119例住院的肺癌患者作为研究组,另选取同期住院的肺部良性病变患者54例作为对照组,检测各组血清肿瘤标志物癌胚抗原(carcinoembryonic antigen,CEA)、鳞状上皮细胞癌抗原(squamous cell carcinoma,SCC)、细胞角化蛋白19片段(cytokeratin 19 fragment,CYFRA21-1)、神经元特异性烯醇化酶(neuron-specific enolase,NSE)、胃泌素释放肽前体(pro-gastrin-releasing peptide,ProGRP)含量并进行组间指标比较和诊断效能分析。结果:肺癌组血清肿瘤标志物含量均高于对照组(P<0.05);腺癌组CEA含量高于鳞癌及小细胞癌组(P<0.05),鳞癌组SCC和CYFRA21-1含量高于腺癌及小细胞癌组(P<0.05),小细胞癌组NSE和ProGRP含量高于腺癌及鳞癌组(P<0.05);CEA检测腺癌的AUC较高(0.987),SCC和CYFRA21-1检测鳞癌的AUC较高(0.994和0.957),NSE和ProGRP检测小细胞癌的AUC较高(0.923和0.944),五项联合检测腺癌、鳞癌及小细胞癌组的AUC(0.991、0.997、0.996)均高于各组指标单独检测(P<0.05)。结论:血清肿瘤标志物对于明确诊断肺癌及鉴别病理类型具有较高的指导价值,CEA对腺癌、SCC和CYFRA21-1对鳞癌、NSE和ProGRP对小细胞癌的诊断价值较高,联合上述各血清指标可提高不同病理类型肺癌的诊断效率。

The learning curve for transurethral enucleation with bipolar energy for benign prostate hyperplasia:a single-surgeon experience of 494 patients

This study was performed to investigate the learning curve of transurethral enucleation with bipolar energy(TUEB)for benignprostatic hyperplasia.The study involved 494 consecutive patients who underwent TUEB for benign prostatic hyperplasia fromAugust 2018 to March 2022 by one surgeon(SJJ,Seoul National University Bundang Hospital,Seongnam,Korea).The patientswere followed up at 1 week,1 month,3 months,and 6 months postoperatively.To evaluate the learning curve of TUEB,perioperativeparameters including the enucleation ratio(enucleated tissue weight/transitional zone volume),TUEB efficiency(enucleatedtissue weight/operation time),and enucleation efficiency(enucleated tissue weight/enucleation time)were analyzed.Functionaloutcomes and postoperative complications were also assessed,including the International Prostate Symptom Score(IPSS),IPSSquality-of-life(QoL)score,and uroflowmetry outcomes.The patients’median age was 72(interquartile range[IQR]:66–78)years,and the estimated prostate volume and transitional zone volume were 63.0(IQR:46.0–90.6)ml and 37.1(IQR:24.0–60.0)ml,respectively.The enucleation ratio,TUEB efficiency,and enucleation efficiency were 0.60(IQR:0.46–0.54)g ml−1,0.33(IQR:0.22–0.46)g min−1,and 0.50(IQR:0.35–0.72)g min−1,respectively,plateauing after 70 cases.The functional outcomes,including total IPSS,IPSS QoL score,and uroflowmetry outcomes,significantly improved at 6 months after TUEB(all P<0.05),but without significant differences over the learning curve.Sixty-five(13.2%)patients developed complications after TUEB,21.5%of whom experienced major complications(Clavien–Dindo grade≥3).The rate of major complications declined as the number ofTUEB cases increased(P=0.013).Our results suggest that the efficiency of TUEB stabilized within 70 procedures.