Diagnostic performance of dynamic contrast-enhanced magnetic resonance imaging parameters and serum tumor markers in rectal carcinoma prognosis

BACKGROUND Rectal carcinoma(RC),one of the most common malignancies globally,presents an increasing incidence and mortality year by year,especially among young people,which seriously affects the prognosis and quality of life of patients.At present,dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)parameters and serum carbohydrate antigen 19-9(CA19-9)and CA125 Levels have been used in clinical practice to evaluate the T stage and differentiation of RC.However,the accuracy of these evaluation modalities still needs further research.This study explores the application and value of these methods in evaluating the T stage and differentiation degree of RC.AIM To analyze the diagnostic performance of DCE-MRI parameters combined with serum tumor markers(TMs)in assessing pathological processes and prognosis of RC patients.METHODS A retrospective analysis was performed on 104 RC patients treated at Yantai Yuhuangding Hospital from May 2018 to January 2022.Patients were categorized into stages T1,T2,T3,and T4,depending on their T stage and differentiation degree.In addition,they were assigned to low(L group)and moderate-high differentiation(M+H group)groups based on their differentiation degree.The levels of DCE-MRI parameters and serum CA19-9 and CA125 in different groups of patients were compared.In addition,the value of DCE-MRI parameters[volume transfer constant(Ktrans),rate constant(Kep),and extravascular extracellular volume fraction(Ve)in assessing the differentiation and T staging of RC patients was discussed.Furthermore,the usefulness of DCE-MRI parameters combined with serum CA19-9 and CA125 Levels in the evaluation of RC differentiation and T staging was analyzed.RESULTS Ktrans,Ve,CA19-9 and CA125 were higher in the high-stage group and L group than in the low-stage group and M+H Group,respectively(P<0.05).The areas under the curve(AUCs)of the Ktran and Ve parameters were 0.638 and 0.694 in the diagnosis of high and low stages,respectively,and 0.672 and 0.725 in diagnosing moderate-high and low differentiation,respectively.The AUC of DCE-MRI parameters(Ktrans+Ve)in the diagnosis of high and low stages was 0.742,and the AUC in diagnosing moderate-high and low differentiation was 0.769.The AUCs of CA19-9 and CA-125 were 0.773 and 0.802 in the diagnosis of high and low stages,respectively,and 0.834 and 0.796 in diagnosing moderate-high and low differentiation,respectively.Then,we combined DCE-MRI(Ktrans+Ve)parameters with CA19-9 and CA-125 and found that the AUC of DCE-MRI parameters plus serum TMs was 0.836 in the diagnosis of high and low stages and 0.946 in the diagnosis of moderate-high and low differentiation.According to the Delong test,the AUC of DCE-MRI parameters plus serum TMs increased significantly compared with serum TMs alone in the diagnosis of T stage and differentiation degree(P<0.001).CONCLUSION The levels of the DCE-MRI parameters Ktrans and Ve and the serum TMs CA19-9 and CA125 all increase with increasing T stage and decreasing differentiation degree of RC and can be used as indices to evaluate the differentiation degree of RC in clinical practice.Moreover,the combined evaluation of the above indices has a better effect and more obvious clinical value,providing important guiding importance for clinical condition judgment and treatment selection.

Impact of Pedestrian Traffic on Saturation Rate of Protected Left-Turn at Urban Intersections

Heavily congested intersections in metropolitan areas in China are facing unique problems due to high travel demand and a high degree of traffic law violations. Based on a study conducted by the authors of this paper, 93% of left-turn vehicles turning left in these areas were slowed in order to avoid conflict with pedestrians. Intertwined pedestrian and vehicular flows can significantly reduce the capacity of exclusive left-turn lane group through reducing saturation flow rate, which increases the congestion at intersections. This paper investigates how the saturation flow rate of exclusive left-turn lane group is affected by the characteristics of pedestrian flow. By analyzing the imagery data collected by video cameras installed at intersections, the research team is able to obtain the characteristics of both vehicular and pedestrian flows, such as speed and spatial locations. The average operating speed at the saturation flow rate with and without pedestrian traffic is used as a direct measurement to evaluate the effect of pedestrians. Based on the statistical analysis, the paper concludes that saturation flow rate is mainly affected by the position of pedestrian in the crosswalk (inside or outside of left-turn vehicle’s trajectory), and the distance between the vehicle and pedestrians. In general, when the distance is less than four meters, the smaller the distance between vehicle and pedestrians, the larger the impact. However, there is no significant impact when the distance is larger than four meters. To accurately quantify the effect, the degree of pedestrian-vehicle impact is defined in four levels. The results show that the difference in the saturation flow rate between the best and the worst level could be 15.7%, which clearly indicates how important it is to enforce pedestrian crossing behavior.

Process for improving the ladle free- opening rate for high aluminum steel in continuous casting

Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are：sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel.

Effect of cooling rate on evolution of superconducting phases during decomposition and recrystallization of (Bi,Pb)-2223 core in Ag-sheathed tape

The reformation of (Bi,Pb)-2223 from the liquid or melt is very important for a melting process of (Bi,Pb)-2223 tape. By combination of quenching experiment with X-ray diffraction (XRD) analysis, the effect of cooling rate on the evolution of three superconducting phases in the (Bi,Pb)-2223 core of Ag-sheathed tape was investigated. The results show that (Bi,Pb)-2223 reformation from the melt seems to experience different routes during slowly cooling at different rates. One is that (Bi,Pb)-2223 phase reformed directly from the melt, and no Bi-2212 participate in this process. The other is that (Bi,Pb)-2223 is converted from the intermediate product, Bi-2212, which formed from the melt during the first cooling stage. Due to the inherent sluggish formation kinetics of (Bi,Pb)-2223 from Bi-2212, only partial (Bi,Pb)-2223 can finally be reformed with the second route.

Effect of varying normal stress on stability and dynamic motion of a spring-slider system with rate- and state-dependent friction

Incorporating rate and state friction laws, stability of linearly stable （i.e., with stiffness greater than the critical value） spring-slider systems subjected to triggering perturbations was analyzed under variable normal stress condition, and comparison was made between our results and that of fixed normal stress cases revealed in previous studies. For systems associated with the slip law, the critical mag- nitude of rate steps for triggering unstable slips are found to have a similar pattern to the fixed normal stress case, and the critical velocity steps scale with a/（b - a） when k = kcr for both cases. The rate-step boundaries for the variable normal stress cases are revealed to be lower than the fixed normal stress case by 7 %-16 % for a relatively large ct = 0.56 with （b - a）/a ranging from 0.25 to 1, indicating easier triggering under the variable normal stress condition with rate steps. The difference between fixed and variable normal stress cases decreases when the α value is smaller. In the same slip- law-type systems, critical displacements to trigger instability are revealed to be little affected by the variable normal stress condition. When k 〉 kcr（V,）, a spring-slider system with the slowness law is much more stable than with the slip law,suggesting that the slowness law fits experimental data better when a single state variable is adopted. In stick-slip motions, the variable normal stress case has larger stress drops than the constant normal stress case. The variable normal stress has little effect on the range of slip velocity in systems associated with the slowness law, whereas systems associated with the slip law have a slowest slip velocity immensely smaller than the fixed normal stress case, by ~ 10 orders of magnitude.

Plastic Flow Modeling of Ti-5 Al-2 Sn-2 Zr-4 Mo-4 Cr Alloy at Elevated Temperatures and High Strain Rates

The true stress-sWain relationships of Ti-5A1-2Sn-2Zr-4Mo-4Cr（TC17） alloy with a wide range of strain rates were investigated by tmiaxial quasi-static and dynamic compression tests, respectively. Quasi- static compression tests were carried out with Instron 8874 test machine, while dynamic compression tests were performed with the split Hopkinson pressure bar （SHPB） which was installed with heating device and synchro- assembly system. The dynamic mechanical behaviors tests of TC17 were carded out from room temperature to 800 ℃ at intervals of 200 ℃ and at high sWain rates （5 500-1 9200 s-l）. The stress-strain curves considering temperature-sWain rate coupling actions were obtained. The Johnson-Cook constitutive model was developed through data fitting of the stress-sWain curves. The material constants in the developed constitutive model can be determined using isothermal and adiabatic stress-strain curves at different strain rates. The Johnson-Cook constitutive model provided satisfied prediction of the plastic flow stress for TC17 alloy.

Performance Analysis of Outage Probability and Error Rate of Square M-QAM in Mobile Wireless Communication Systems over Generalized α-μ Fading Channels with Non-Gaussian Noise

This paper derives new and exact closed-form expressions for the average symbol error rate(SER) of square M-ary quadrature amplitude modulation(M-QAM) in wireless communication systems over theα-μfading channels subject to an additive non-Gaussian noise. The obtained expressions take into account static and mobile wireless receivers. In addition, a closed-form expression for the outage probability in mobile networks is obtained. Please note that all derived expressions in this paper a valid for integer and non-integer values of the fading parameters. Analytical results are presented to study the impact of noise shaping parameter, severity of fading, and mobility on the average SER. Monte-Carlo simulations results are also provided to validate the accuracy of the analytical results.

NO_3^-/NH_4^+ ratios affect plant growth, chlorophyll content,respiration rate, and morphological structure in Malus hupehensis seedlings

Malus hupehensis （Pamp.） Rehd. is a widely cultivated rootstock in China. We studied the effect of three NO3-/NH4＋ ratios （100/0, 50/50, and 0/100, molar basis） at total nitrogen （N） concentration of 8 mmoL L-1 in a nutrient solution on M. hupehensis seedlings. Plant biomass, NO3- and NH4＋concentrafion, chlorophyll con- tent, respiratory rate, and cellular structure were investi- gated. M. hupehensis seedlings at the NO3-/NH4＋ ratio of 50/50 had the highest level of fresh weight, dry weight, shoot length, and chlorophyll （a, b, and a ＋ b） content, but the lowest respiration rate in the leavesand roots. In addition, thickness and numbers of palisade and spongy tissue cells of the leaves were greater with this treatment than with other treatments. At the NO3-/NH4＋ ratio of 100/0, the leaves and roots had higher NO3- concentration and lower NH4＋ concentration. However, the opposite trend occurred at the NO3-/NH4＋ ratio of 0/100. Chloro- phyll （a, b, and a ＋ b） content was lowest at the NO3-/NH4＋ ratio of 100/0 than at the other ratios. At the NO3-/ NH4＋ ratio of 0/100, oxygen （02） consumption increased in the leaves and roots, and irregular epidermis and cortex cells were observed in the root apical meristematic and mature region. Our results indicated that the NO3-INH4＋ ratio at 50/50 was suitable for growth of M. hupehensis seedling to achieve the highest biomass production and efficiency.

THE BROAD-BAND CCD PHOTOMETRY AND DUST PRODUCTION RATES OF COMET HALE-BOPP

Based upon broad-band CCD observation data of comet Hale-Bopp obtained by a 60cm telescope at Xinglong Station of Beijing Astronomical Observatory during March-August, 1996, the photometric results of comet Hale-Bopp are reported. Using the photometric results, the dust production rate, radius and mass of nucleus of comet Hale-Bopp are estimated as follows: dM/dt～1.5×10 5 kgs -1, R n～35.5km, and M n～5.65×10 16kg.

基于云-端高精度地图的油菜无人播种作业系统设计与试验

[目的/意义]针对人工采集南方中小田边界信息操作繁琐、无人拖拉机转场作业效率低且在转弯调头处留下较大漏作业区域的问题,本研究搭建了一种基于云-端高精度地图的油菜无人播种作业系统。[方法]系统采用“无人机构建高精度地图+远程网页端规划作业路径”方法,使用无人机采集影像数据构建高精度地图,基于高精度地图框选田块实现梭行外螺旋路径自动生成,完成直播机组远程路径规划及调度作业。系统采用梭行外螺旋全覆盖路径规划方法,利用两退三切鱼尾调头方法完成梭行路径换线。为完成外螺旋路径换线,在田块边角设计了一退两切转弯换线方法,减小了油菜无人播种作业系统在转弯或调头过程产生的漏作业区域面积,进一步提升了播种作业覆盖率,并开展梭行外螺旋全覆盖路径与梭行、套行路径作业面积和作业覆盖率对比仿真试验,以Case TM1404型拖拉机搭载智能播种施肥一体机为试验平台,开展了田间试验。[结果和讨论]试验结果表明,梭行外螺旋全覆盖路径较梭行与套行作业路径,漏作业率减小18.58%~26.01%。使用无人机构建的高精度地图平面误差最大为3.23 cm,导航作业过程中最大横向偏差为7.94 cm,最大平均绝对偏差为1.85 cm,作业覆盖率为93.16%。[结论]本研究所构建的油菜无人播种作业系统有效可行,可为南方中小田块油菜无人播种作业提供技术参考。未来将探索不规则田块情况下的油菜无人播种作业模式,进一步提高系统适用性。

ASTM E1268-19带状组织评定方法研究

介绍了美标ASTM E1268-19显微组织带状物级别或取向度的评级方法。采用ASTM E1268-19与GB/T13299—91试验方法,评定了热轧板卷试样的珠光体带状组织,并对ASTM E1268标准方法中检测视场的影响因素进行了分析。结果表明:增加检测视场数有利于提高定量评定结果的准确度;对于带状严重的组织,因其平行测量线容易全部落入单相组织内部或外部,对带状等级BR(banding rate)值的测量结果影响较大,针对此类情况,有必要增加检测视场数或测量线的数量,以提高BR的检测精度。

硬态车削对18CrNiMo7-6钢表面完整性影响研究

介绍了硬态车削淬硬钢表面粗糙度与表层残余应力研究现状。通过设计单因素试验,对硬态车削18CrNiMo7-6渗碳钢圆棒试样的三维表面粗糙度与表层残余应力进行分析,探究硬态车削工艺参数对淬硬钢表面完整性的影响规律。结果表明干式硬态车削18CrNiMo7-6渗碳钢可获得较好的表面三维粗糙度与残余压应力,残余应力沿深度方向分布表现为先增大至最大值后逐渐减小至稳定值。在硬态车削过程中,进给速度对工件表面完整性影响最大,切削速度影响次之,背吃刀量影响最小。

High Strain Rate Induced Plasticity-increasing of Metallic Materials under Tension

The effect of strain rate on plasticity has been Investigat-ed for three metallic materials with dynamic tension tech-nique. A phenomenon of high strain induced plasticity -increasing was found for tested materials. The elongation of quenched 30CrMnSiNi2A is 14. 5% under 40 m/s loading rate which is more than two times of the 7 % un-der 0. 5 mm/min. This typic high strain rate induced plasticity - Increasing phenomenon is associated with adiabatic heating, strain twinning and suppression of strain - induced - phase transformation.

二维片状相对论电子束到靶规律研究

相对论电子束在理想顺磁环境下能够以较高的注量率击中靶目标,但实际情况中由于受环境的影响,相对论电子束的传输方向可能会与地磁场呈小角度偏差,因此会受到地磁场的作用产生拉莫尔进动,影响电子束的到靶瞄准以及到靶注量。基于二维片状相对论电子束,分别对相对论电子束顺磁和偏离磁场3°角两种传输情况进行仿真模拟,通过模拟束团的传输过程,分析研究了顺磁环境下不同传输距离束团到靶率的变化规律,以及偏离磁场3°角时传输过程中注量率的变化规律,为相对论电子束到靶率的预估和靶目标的瞄准提供数据参考。

一个考虑扩散的Holling-Tanner捕食-食饵模型研究

研究了一个在齐次Neumann边界条件下考虑扩散的Holling-Tanner捕食-食饵模型.首先,得到了系统的全局吸引子和持久性;然后,讨论了系统正常数平衡解的全局渐进稳定性;最后,研究了系统的Turning失稳性质.

1-MCP处理对梨枣低温贮藏生理的影响

研究不同浓度1-甲基环丙烯(1-MCP)处理对梨枣低温(0±1)℃贮藏生理的影响。结果表明:1-MCP处理在一定程度上可减慢梨枣中VC和可滴定酸含量的损失,减缓失重率的上升和转红指数的增加,但对呼吸强度的影响不明显。0.5mg/L 1-MCP可以明显延缓梨枣相对电导率和丙二醛(MDA)含量的增加。

Al-Si合金回转件车削表面雪花斑形成机理

Al-Si合金回转件车削加工时,工件表面会产生明暗相间的雪花斑,影响工件使用性能.为了找到雪花斑产生的机理,针对ZL101铸件加工表面进行了粗糙度测量,并对工件有雪花斑和无雪花斑位置进行了力学性能测试和微观组织观察.结果表明:车削工件表面有雪花斑位置的粗糙度显著大于无雪花斑位置的粗糙度;该位置取样样品的强度小于无雪花斑位置取样样品的强度.微观组织观察表明,有雪花斑位置样品的α-Al相晶粒尺寸和枝晶间距显著大于无雪花斑的,且该位置共晶组织中的硅相颗粒尺寸及共晶组织所占比例均大于无雪花斑的.组织粗大和共晶组织的增加促使Al-Si合金切削加工过程中切削表面雪花斑的形成.

干式空心并联电抗器绕组绝缘状态在线监测方法

干式空心并联电抗器用于无功补偿与抑制工频过电压,在电网中的数量和容量日益增加,事故率却高居不下,其中,绕组匝间绝缘故障占比高居首位,亟需有效的绕组绝缘状态在线监测手段。利用有限元软件对干式空心并联电抗器进行“场-路”耦合仿真,通过分析其绕组异匝和同匝股间短路的电、磁、力变化特征,研究绕组匝间短路故障的发展过程、形成机理,探求便于故障监测的敏感状态量,提出了基于有功功率损耗变化率的绕组绝缘状态在线监测方法。研究结果表明:绕组异匝股间短路对电抗器电、磁、力等物理参量的影响大于相同位置同匝股间短路工况,且异匝股间短路发生在电抗器绕组端部的影响最大。有功功率损耗对电抗器绕组绝缘故障发展的过程反应敏感、易于监测,可通过选择合适的绝缘故障预警值和绝缘失效值,基于有功功率损耗变化率进行状态判断,能够实时发现电抗器绕组绝缘故障,便于及时采取措施,阻止故障蔓延。

港机-集装箱用钢丝绳捻制技术研究

对港机 -集装箱用钢丝绳主要品种在实际使用中存在的质量问题进行详细分析 ,认为抗疲劳性能差和使用寿命短的主要原因是钢丝韧性指标低、外层股之间的缝隙太小和钢丝绳油脂不到位 ;钢丝绳表面浪形和金属绳芯外逃是由于成型率过高、波动偏大 ,各股捻制张力不均匀和顺向捻制不到位。针对存在的问题 ,提出采用小捻距 ,提高增径率 ,控制股间缝隙 。

PDCA循环法对急诊标本周转时间合格率的影响

目的探讨运用PDCA循环法后,急诊检验标本周转时间(TAT)合格率的变化。方法统计分析西北妇女儿童医院医学检验中心2022年1月至4月共8455例急诊标本报告,统计标本TAT合格率并采用鱼骨图分析不合格原因及处理措施;统计运用PDCA循环法后2022年5月至2023年1月共20140例急诊标本报告,比较PDCA循环法实施前后急诊标本TAT合格率的变化。结果PDCA实施后,急诊标本TAT合格率高于PDCA实施前,差异有高度统计学意义(P<0.001)。其中不同急诊项目中,除免疫发光外,急诊血常规、尿常规、粪常规、血凝四项和生化标本TAT合格率均较PDCA循环前升高,差异有高度统计学意义(P<0.001)。结论通过PDCA循环管理法,西北妇女儿童医院医学检验中心急诊标本TAT合格率得到了明显提升,这不仅提升了检验效率和临床服务,同时对急、危重患者的及时救治具有重要意义。