膝关节Ramp损伤的研究进展

Ramp损伤(RL)是膝关节内侧半月板后角与关节囊移行区域损伤,常见于慢性前交叉韧带(ACL)损伤患者,也可孤立发生。Ramp区对维持膝关节功能及保护ACL重建移植物有重要作用,膝关节MRI在诊断RL上敏感度中等但特异度较高,关节镜是诊断的金标准。对RL的认识目前处于一个“再认识”的阶段,对其最佳的处理方式是近年来研究的热点。本文结合近年来研究现状,从RL的流行病学、解剖学、产生机制、分型、诊断以及手术治疗方面进行综述,以期为RL的研究及诊治提供参考。

前交叉韧带断裂合并内侧半月板Ramp区损伤的临床疗效分析

目的探讨前交叉韧带(anterior cruciate ligament,ACL)断裂合并内侧半月板后角Ramp区损伤同期治疗的临床疗效,对ACL断裂合并内侧半月板Ramp区损伤患者的手术治疗提供一些参考。方法2018年3月至2020年8月佛山市第一人民医院关节骨外科收治23例ACL合并内侧Ramp区损伤患者,其中男15例,女8例;年龄19~64岁,平均(36.4±13.6)岁。接受关节镜下韧带重建同期行内侧半月板后角Ramp区修复手术,术后佩戴可调节膝关节角度的铰链支具3个月。术后3 d内行膝关节正侧位X线检查及CT骨隧道重建,末次随访时以前抽屉试验、Lachman试验评估膝关节稳定性及韧带松弛度,以2000国际膝关节评分委员会(international knee documentation committee,IKDC)膝关节评分、Lysholm膝关节评分和Tegner膝关节运动评分评估膝关节活动度及功能。结果23例均获随访,随访时间24~48个月,平均(34.0±8.0)个月。末次随访时ACL断裂合并Ramp区损伤患者2000 IKDC膝关节主观评分、Lysholm膝关节评分、Tegner膝关节运动评分分别从术前的(70.3±4.9)分、(58.0±7.0)分、(4.3±0.8)分提高到术后的(85.0±5.2)分、(81.6±6.1)分、(7.3±1.4)分,手术前后评分比较差异有统计学意义。23例患者患侧膝关节活动度平均(135.0±3.4)°,无活动受限。术后患者膝关节正侧位X线片示对线对位良好,未出现畸形,膝关节CT重建显示股骨及胫骨隧道位置良好,锚钉位置良好、固定牢固,MRI冠状面、矢状面、横断面序列未发现半月板后角Ⅲ级信号。23例患者随访期间均未发生韧带再损伤,未因半月板再次损伤而行关节镜手术。结论对ACL断裂合并内侧半月板Ramp区损伤患者,膝关节镜ACL重建同期行内侧半月板Ramp区修补术,术后膝关节稳定性、活动及功能明显改善,可进一步减少膝关节损伤,获得比较满意的活动度及关节功能。

Application of Connected Truck Data to Evaluate Spatiotemporal Impact of Rest Area Closures on Ramp Parking

Ensuring adequate access to truck parking is critical to the safe and efficient movement of freight traffic. There are strict federal guidelines for commercial truck driver rest periods. Rest areas and private truck stops are the only places for the trucks to stop legally and safely. In locations without sufficient parking areas, trucks often park on interstate ramps, which create safety risks for other interstate motorists. Historically, agencies have employed costly and time intensive manual counting methods, camera surveillance, and driver surveys to assess truck parking. Connected truck data, available in near real-time, offers an efficient alternative to practitioners to assess truck parking patterns and identify areas where there may be insufficient safe parking spaces. This paper presents a case study of interstate I-70 in east central Indiana and documents the observed spatiotemporal impacts of a rest area closure on truck parking on nearby interstate ramps. Results showed that there was a 28% increase in parking on ramps during the rest area closure. Analysis also found that ramps closest to the rest area were most impacted by the closure, seeing a rise in truck parking sessions as high as 2.7 times. Parking duration on the ramps during rest area closure also increased drastically. Although it was expected that this would result in increased parking by trucks on adjacent ramps, this before, during, after scenario provided an ideal scenario to evaluate the robustness of these techniques to assess changing parking characteristics of long-haul commercial trucks. The data analytics and visualization tools presented in this study are scalable nationwide and will aid stakeholders in informed data-driven decision making when allocating resources towards improving the nations commercial vehicle parking infrastructure.

Controlling Congestion in Al-Seeb Highway Using Ramp Metering (Case Study)

This paper represents a case study of traffic congestion within a section on Al Seeb Street highway due to the on-ramp merging of vehicles that causes a bottleneck in the mainline road. It studies the efficiency of installing ramp metering within a ramp within the selected study zone. This is done by simulating the collected data using Vissim software by drawing three one-hour-long scenarios;the first scenario reflects the data collected for 30 minutes duration and is used as a base scenario to draw the other two scenarios, which are reflected as factored-up scenarios to create a situation observed in the early morning in the study zone at 6:00-7:00 in which slowing down of speeds exist, and breakdown is raised in working days. The two factoring-up scenarios were as follows: one without ramp metering and the other without ramp metering. Each scenario was calibrated and run five times with random seeds, and then the average was considered. The simulation examines the ability of RM to smooth traffic in mainline and reduce queuing on on-ramp roads within the selected study zone by comparing the performance of the network for the scenarios and comparing them in terms of the overall delays, number of stops and the average speeds for the vehicles within the mainline. The results showed a good performance reflected by the scenario with ramp metering with a reduction of the overall delay, a decrease in stops number and an increase of the average speed were achieved. For the base scenario, a visualization (video extracted from Vissim software) was extracted, showing no need to install RM with an associated table showing a number of stops equal to zero with an average speed of 102.74 km/h and a total delay of 6045 seconds. For the second scenario with no RM, a visualization was extracted showing a slowing down of speeds for vehicles within the mainline while vehicles merging from the on-ramp and need to be controlled with a table showing a number of stops equal to 16 and an average speed equal to 58 km/h and a total delay of 916,874 seconds. For the third scenario with RM, a visualization was extracted showing good control of the second scenario with a table showing the number of stops equal to 6, an average speed equal to 61 km/h and a total delay equal to 484,466 seconds. Ten literatures in regard to this study have been reviewed. The data collected are quantitative, which are collected using an indirect manual counting method and then the data is used to feed the software for simulation.

Design and Engineering of Urban Interchange Ramp Bridge Structure

This paper analyzes the structural design of an urban interchange ramp bridge from four aspects,which are the superstructure,pier structure,foundation structure,and deck structure design to summarize the structural design ideas of this urban interchange ramp bridge,which can be used as a reference for future construction of the same bridge.

A Review of the Key Points in the Design of Small-Radius Curved Ramp Bridges

This article explores the fundamentals of small-radius curved ramp bridges.It covers the selection of box girder spans,support methods,and forms,along with design optimization techniques for this type of bridge structure.The purpose of this paper is to provide robust support for enhancing the design quality of these bridges and ensuring their efficacy in real-world applications.

Continuum modeling for two-lane traffic flow

In this paper, we study the continuum modeling of traffic dynamics for two-lane freeways. A new dynamics model is proposed, which contains the speed gradient-based momentum equations derived from a car-following theory suited to two-lane traffic flow. The conditions for securing the linear stability of the new model are presented. Numerical tests are can＇ied out and some nonequilibrium phenomena are observed, such as small disturbance instability, stop-and-go waves, local clusters and phase transition.

Extended speed gradient model for traffic flow on two-lane freeways

In this paper, the speed gradient （SG） model is extended to describe the traffic flow on two-lane freeways. Terms related to lane change are added into the continuity equations and velocity dynamic equations. The empirically observed two-lane phenomena, such as lane usage inversion and lane change rate versus density, are reproduced by extended SG model. The local cluster effect is also investigated by numerical simulations.

A continuum traffic flow model with the consideration of coupling effect for two-lane freeways

A new higher-order continuum model is proposed by considering the coupling and lane changing effects of the vehicles on two adjacent lanes. A stability analysis of the proposed model provides the conditions that ensure its linear stability. Issues related to lane changing, shock waves and rarefaction waves, local clustering and phase transition are also investigated with numerical experiments. The simulation results show that the proposed model is capable of providing explanations to some particular traffic phenomena commonly observable in real traffic flows.

Analysis of the wave properties of a new two-lane continuum model with the coupling effect

A multilane extension of the single-lane anisotropic continuum model （GK model） developed by Gupta and Katiyar for traffic flow is discussed with the consideration of the coupling effect between the vehicles of different lanes in the instantaneous traffic situation and the lane-changing effect. The conditions for securing the linear stability of the new model are presented. The shock and the rarefaction waves, the local cluster effect and the phase transition are investigated through simulation experiments with the new model and are found to be consistent with the diverse nonlinear dynamical phenomena observed in a real traffic flow. The analysis also focuses on empirically observed two- lane phenomena, such as lane usage inversion and the density dependence of the number of lane changes. It is shown that single-lane dynamics can be extended to multilane cases without changing the basic properties of the single-lane model. The results show that the new multilane model is capable of explaining some particular traffic phenomena and is in accordance with real traffic flow.

前交叉韧带断裂合并半月板ramp区损伤的临床治疗经验

目的分享和探讨前交叉韧带断裂合并半月板ramp区损伤在关节镜下的临床经验与疗效。方法56例前交叉韧带断裂合并半月板ramp区损伤的患者,按手术方式分为2组,对照组29例行膝关节镜下可调节袢-自体腘绳肌腱单束重建术,观察组27例在其基础上采用膝关节镜下可调节袢-自体腘绳肌腱单束重建术+半月板ramp区缝合修复术。术后随访以IKDC、Lysholm、步态测试仪,关节稳定测定为膝关节功能恢复的主观评价指标。结果56例平均随访18.7个月,平均年龄26.3岁,未发生感染及关节僵硬等并发症。观察组半月板临床愈合率为92.59%,明显高于对照组的68.96%,术前2组患者IKDC、Lysholm评分差异无显著性(P>0.05),术后6个月观察组膝关节IKDC、Lysholm评分均明显优于对照组(P<0.05)。结论膝关节镜下同期行可调节袢-自体腘绳肌腱单束重建术+半月板ramp区缝合修复术更有利于半月板愈合,能够获得更好的膝关节稳定性,值得临床推广。

磁共振成像诊断前交叉韧带撕裂伴Ramp损伤的价值

目的探讨前交叉韧带(ACL)撕裂患者术前磁共振成像(MRI)诊断Ramp损伤的价值,以期为临床治疗提供参考。方法选取2019年6月—2022年7月在四川省骨科医院治疗的ACL撕裂患者126例为研究对象,给予MRI和关节镜检查。比较分析MRI诊断Ramp损伤的价值,同时分析合并和未合并Ramp损伤患者临床资料、影像资料差异,尝试明确ACL撕裂合并Ramp损伤的影响因素。结果MRI诊断与关节镜检查一致性Kappa值为0.527,P<0.001,一致性一般。MRI诊断ACL合并Ramp损伤的灵敏性、特异性、准确性、阳性预测值和阴性预测值分别为45.00%、98.11%、89.68%、82.82%和90.43%。合并Ramp损伤组病程≥6周患者比例高于未合并Ramp损伤组患者(P<0.05);2组患者性别构成、年龄、身体质量指数等比较,差异无统计学意义(P>0.05)。合并Ramp损伤组内侧半月板后角与关节囊连接处出现线样液性高信号、内侧半月板后角边缘出现纵行撕裂、胫骨前移、股骨内侧髁骨挫伤、ACL完全撕裂患者所占比例高于未合并Ramp损伤组患者,差异均有统计学意义(P<0.05)。多因素逐步Logistic回归分析结果显示:病程、内侧半月板后角与关节囊连接处出现线样液性高信号、内侧半月板后角边缘出现纵行撕裂、胫骨前移、股骨内侧髁骨挫伤是ACL撕裂患者发生Ramp损伤的影响因素(P<0.05)。结论MRI诊断ACL撕裂合并Ramp损伤的灵敏性较低,但特异性较高。ACL撕裂合并Ramp损伤受病程、内侧半月板后角与关节囊连接处出现线样液性高信号、内侧半月板后角边缘出现纵行撕裂、胫骨前移、股骨内侧髁骨挫伤的影响。本研究基本复制了临床情况,具有实用价值。

MRI成像在评价膝关节内侧半月板Ramp损伤稳定性中的价值

Ramp损伤作为前交叉韧带撕裂的继发性损伤之一,损伤区域能否被及时识别和修复将对前交叉韧带重建患者的手术愈后效果会产生重要影响^([1-2])。由于解剖位置的特殊性,Ramp损伤在传统的前路或前外路关节镜手术中的漏诊率较高^([3]),而膝关节MRI成像凭借着对软组织及纤维结构的显示具有高分辨力优势.

A viscous continuum traffic flow model with consideration of the coupling effect for two-lane freeways

In this paper, the viscous continuum traffic flow model for a single lane is extended to the traffic flow for two-lane freeways. The proposed model is a higher-order continuum model considering the coupling and lane changing effects of the vehicles on two adjacent lanes. It results from integrating the Taylor series expansion of the viscous continuum traffic flow model proposed by Ge （2006 Physiea A 371 667） into the multi-lane model presented by Daganzo （1997 Transpn. Res. B 31 83）. Our proposed model may be used to describe non-anisotropic behaviour because of lane changing in multi-lane traffic. A linear stability analysis is given and the neutral stability condition is obtained. Also, issues related to lane changing, shock waves and rarefaction waves, local clustering and phase transition are investigated through a simulation experiment. The simulation results show that the proposed model is capable of explaining some particular traffic phenomena commonly observable in real world traffic flow.

Micro-simulation model of two-lane freeway vehicles for obtaining traffic flow characteristics including safety condition

Unidirectional two-lane freeway is a typical and the simplest form of freeway. The traffic flow char- acteristics including safety condition on two-lane freeway is of great significance in planning, design, and manage- ment of a freeway. Many previous traffic flow models are able to figure out flow characteristics such as speed, den- sity, delay, and so forth. These models, however, have great difficulty in reflecting safety condition of vehicles. Besides, for the cellular automation, one of the most widely used microscopic traffic simulation models, its discreteness in both time and space can possibly cause inaccuracy or big errors in simulation results. In this paper, a micro-simula- tion model of two-lane freeway vehicles is proposed to evaluate characteristics of traffic flow, including safety condition. The model is also discrete in time but continu- ous in space, and it divides drivers into several groups on the basis of their preferences for overtaking, which makes the simulation more aligned with real situations. Partial test is conducted in this study and results of delay, speed, volume, and density indicate the preliminary validity of our model, based on which the proposed safety coefficient evaluates safety condition under different flow levels. It is found that the results of this evaluation coincide with daily experience of drivers, providing ground for effectiveness of the safety coefficient.

Reconstruction of the Yangtze Ramp during Floian to Darriwilian(Ordovician)in South China:Its Morphology,Controlling Factors and Significances

A robust stratigraphic framework and a coherent depositional ramp model for the Zitai,Dawan,Meitan and Ningkuo formations of Floian–Darriwilian age(Early–Middle Ordovician)in the Yangtze(Daoba,Xiangshuidong,Daling,Gudongkou and Honghuayuan sections)and Jiangnan regions(Nanba section)was created based on lithofacies and major element analysis.Three siliciclastic(LF1–3)and six carbonate(LF4–9)lithofacies are recognized representing sediments that were deposited in mixed siliciclastic and carbonate ramp environment.The intensity of mixed sedimentation and terrigenous input were evaluated using the elemental proxies Intensity of Mixed sedimentation(IM)and Aluminum Accumulation Rate(Al AR),as well as their mean values during certain time intervals.Mixed sediments are most well-developed along the marginal Yangtze region,strongly impacted by recurrent influx of westerly derived terrigenous materials in response to global eustatic changes and regional tectonic movements,shaping the gently southeast-dipping morphology.Regular terrigenous influx resulted in periods of enhanced primary productivity on the Yangtze Ramp as evidenced by matching biodiversity peaks in planktonic organisms,i.e.,chitinozoans and acritarchs.Brachiopods and other shelly fauna were also able to proliferate as new niches developed along the gently dipping ramp floor with substrate changes.The biodiversification patterns suggest that terrigenous influx controlled in part by regional tectonics played a more important role than previously thought in the development of Great Ordovician Biodiversification Event in South China.

前交叉韧带损伤合并半月板胫骨韧带损伤型Ramp损伤的临床研究

目的:探讨前交叉韧带(ACL)损伤伴发的一种特殊类型的Ramp损伤的发生率及其与现有各类型Ramp损伤的区别、处理方式和临床疗效。方法:回顾性观察2017年1月~2020年6月在江苏省中医院进行关节镜下ACL重建手术的286例患者术中记录的内侧半月板Ramp区损伤情况和Thaunat分型。共42例存在Ramp损伤,其中6例Ramp区损伤并不涵盖在Thaunat分型方法中,我们将这个特殊类型Ramp损伤命名为半月板胫骨韧带损伤型Ramp损伤,该类型损伤的缝合方式也与其他类型的Ramp损伤不完全相同。关节镜下缝合后,根据患者术后12月的膝关节磁共振成像(MRI)评估Ramp损伤愈合情况;术后2年随访时进行Lachman试验,记录患侧-健侧的KT-2000差值、Lysholm和Tegner评分,并与术前进行对比,评估膝关节稳定性和主观功能变化。结果:半月板胫骨韧带损伤型Ramp损伤选择2号PSDII线,通过所建立的后内侧入路,以全内缝合钩结合缝线对Ramp损伤区及后方的关节囊组织进行环绕缝合。术后12月随访时,MRI显示所有半月板胫骨韧带损伤型Ramp损伤患者的Ramp区域信号正常;术后2年随访时,所有半月板胫骨韧带损伤型Ramp损伤患者的患侧-健侧的KT-2000差值由术前8.4±2.4 mm降低至2.1±1.1 mm,Lysholm评分由术前58.7±10.5分提高至90.7±8.5分,Tegner评分由3分提高至6分,且差异均具有统计学意义(P<0.01)。结论:我们的观察提示前交叉韧带损伤合并有Ramp损伤的发生率为14.7%,其中半月板胫骨韧带损伤型的Ramp损伤占所有Ramp损伤的14.3%,该类型Ramp损伤经全内缝合钩缝线缝合的愈合率为100%。

基于多线激光雷达的井下斜坡道无人矿卡定位与建图方法

井下斜坡道的定位与建图是实现井下斜坡道无人驾驶的关键技术之一,矿山井下斜坡道区域为典型非结构化环境特征,且道路具有一定倾斜角度,采用传统SLAM算法无法获得精确里程计信息,导致定位与建图精度难以满足无人矿卡行驶需求。针对上述问题,通过研究激光SLAM(Simultaneous Localization And Mapping)算法LeGO-LOAM,笔者提出一种适用于矿山井下斜坡道环境的定位与建图方法。首先,针对井下斜坡道口两侧均为光滑水泥墙壁,特征点稀少问题,设计了基于人工路标的辅助增强定位方法,有效增加点云特征数量,从而优化位姿估计结果,避免建图漂移现象;然后在特征预处理阶段,提出了一种基于激光点云高度差与坡度信息融合的提取地面点高效算法,通过改善地面地点的选取策略,针对倾斜坑洼路面仍能有效识别地面点,解决了井下斜坡道定位与建图倾斜角度大、误差大等问题;其次,基于CVC(Curved-Voxel Clustering)聚类算法设计了一种斜坡道点云曲率体素聚类算法,采用曲率体素和基于哈希的数据结构对点云进行分割,大幅提高在井下稀疏、噪声环境下点云聚类的鲁棒性;最后,运用Scan-To-Map进行点云匹配,同时兼顾点云配准的性能与速度。在中钢集团山东某井下斜坡道的现场实验证明:与原算法相比精度提升13.15%,Z轴误差降低22.3%,地图质量明显提升,能有效解决井下无人驾驶建图及定位的难题。

考虑风电爬坡灵活调节的碳捕集电厂低碳经济调度

为实现“双碳”目标,风电等可再生能源的使用是减少碳排放的根本途径,而碳捕集电厂是降低碳排放的直接手段。但风电具有与生俱来的波动性,风电的骤升骤降会影响碳捕集电厂“电碳耦合”特性,从而对碳捕集效果带来不利影响。而储液罐通过增减自身溶液量可近似地存储释放能量,为解决上述问题提供了可能。该文首先搭建碳捕集电厂数学模型,分析储液罐通过增减溶液量带来的储放能量与碳捕集设备能耗之间的关联,研究储液罐的双向调节能力;然后,提出上爬坡碳超前补偿和下爬坡碳滞后补偿调度策略,双向调节储液罐使碳捕集电厂电碳解耦;接着,构建跟随风电爬坡进行调节的低碳经济调度模型;最后,对含碳捕集电厂、高碳电厂和风电场的电力系统进行仿真,证明所提方法的有效性。

Strategies for Ramp Route Design of Highway Interchange

The rapid advancement of urban transportation in modern China has driven urban economic developments.However,the progressively congested traffic conditions have affected the productivity and daily life of the people.To mitigate the congestion problem,necessary road designs should be implemented along the highways,for example highway interchanges.The application of highway interchanges in past cases have proven to effectively avoid traffic flow conflicts,reduce highway traffic congestion,and reduce traffic accidents,this is conducive to ensuring the safety and efficiency of the highway.In order to improve the safety and convenience of urban road traffic,this paper analyzes the strategy of using interchange ramp route designs for highway traffic.