Surgical strategy used in multilevel cervical disc replacement and cervical hybrid surgery:Four case reports

BACKGROUND Multilevel artificial cervical disc replacement and anterior hybrid surgery have been introduced as reliable treatments for multilevel cervical degenerative disc disease.Surgical techniques are important for resolving patients’symptoms and maintaining the normal functioning of cervical implants.However,the use of inappropriate surgical strategies could lead to complications such as implant migration and neurological deficit.In this paper,we summarize our surgical strategies used in multilevel cervical disc replacement and hybrid surgery into five major notes.CASE SUMMARY We share the key notes and our surgical procedures in the form of four typical case presentations.All patients were diagnosed with cervical degenerative disc disease with myelopathy or radiculopathy and needed multilevel cervical spine surgery.The first case demonstrated that index levels indicating the presence of highly serious spinal cord compression required a prioritized decompression.The second case demonstrated that the disc replacement should be performed before fusion in cervical hybrid surgery.The third and forth cases demonstrated that a top-down implantation sequence was needed in continuous two-level cervical disc replacement.The symptoms of all patients were significantly relieved after surgery.CONCLUSION We hope that our surgical strategies can help improve the performance and outcomes of multilevel cervical spine surgery.

Strategy of dealing with left subclavian artery in total arch replacement combined with stented elephant trunk implantation for Stanford type A aortic dissection

Objective To summarize the experiences of ligating left subclavian artery ( LSA ) in total arch peplacement and stented elephant trunk implantation for Stanford type A aortic dissection patients with difficulty in exposing the LSA. Methods Total arch replacement and stented elephant trunk implantation were performed on 79 consecutive

大庆油田SEC储量储采形势及增储策略

大庆油田目前已进入双特高后期开发阶段,储采比逐渐降低,SEC储量替换率仅为0.4左右,增储与稳产需求的矛盾日益加剧。通过对大庆油田目前SEC储采现状、增储特点、影响因素进行分析,认为资源品质下降、长期低油价、成本上升以及评估精细程度不足这4个方面是造成储采失衡的主要原因。为改善储采状况,大庆油田形成了较为有效的增储做法,结合大庆油田实际提出了加强技术创新与应用、提升新区勘探与开发效率、优化天然气资源利用、强化精细管理与成本控制、融入绿色发展与新能源等实现储采平衡的工作方向及增储策略。研究成果为东部同类老油田的长远高质量发展提供决策参考。

面向无线异构传感器网络的三维覆盖研究

【目的】为达到增强无线异构传感器网络(HWSN)三维覆盖能力的目的,提出了一种基于改进蜜獾优化算法(IHBA)的无线异构传感器网络三维部署方法。【方法】首先,结合自适应果蝇优化算法,增强算法的随机搜索性,便于算法得到全局最优解,然后引入替换最差个体策略,避免适应度过低的个体占据种群位置,提高算法收敛速度,同时引入新个体提高种群多样性,避免算法个体早熟。【结果】将该算法应用于无线异构传感器网络的覆盖优化,相比标准蜜獾算法,其网络覆盖率提升18.1%。【结论】仿真结果表明,该算法收敛速度更快,可以有效提高无线异构传感器的网络覆盖能力,整个网络的节点分布也更加均匀。

协同理论视角下高职生顶岗实习成效提升策略研究——以旅游外语专业为例

顶岗实习是高职院校专业教学的重要组成部分,是学生提前熟悉岗位、提高职业综合能力的必备途径,也是锤炼学生意志品格、引导学生适应职场、融入社会的重要方式。本文以旅游外语专业为例,探讨高职院校学生顶岗实习协同管理模式的优化策略,以提高学生顶岗实习的成效和专业人才的培养质量。

氨–柴油双燃料发动机燃烧的光学诊断研究

为了解决氨燃料在发动机中燃烧不稳定的问题,通过开展氨–柴油双燃料发动机燃烧过程的光学诊断研究,以获得柴油引燃氨的燃烧及火焰发展特性,研究了不同氨替代率及不同柴油喷射时刻对氨–柴油双燃料缸内燃烧和火焰发展特性的影响。结果表明:随着氨替代率的增加,缸压和放热率峰值先增加后减小,燃烧相位不断后移,滞燃期和燃烧持续期延长,70%和80%氨替代率下放热率峰值相比40%氨替代率降低了41.7%和58.8%。随氨替代率增加,火焰光强和火焰面积均逐渐减小,氨替代率为80%时,火焰向燃烧室中心的扩散燃烧速度变慢,火焰面积峰值为612.5 mm2,占燃烧室总面积约19%,燃烧表现较差;随着柴油喷射时刻的不断推迟,缸压和放热率峰值先增加后减小,燃烧相位不断后移,燃烧持续期先减小后增加,火焰光强和火焰面积均先增加后减小。-25°喷射时刻缸压和放热率峰值分别为4.28 MPa和115.4 J/(°),相比其他时刻具有较好的放热性能。与-20°喷射时刻相比火焰光强和火焰面积分别增加了15%和42.5%,此时燃烧室中心未燃区域最小,对氨有较好的引燃效果。

Research on Performance Optimization of Spark Distributed Computing Platform

Spark,a distributed computing platform,has rapidly developed in the field of big data.Its in-memory computing feature reduces disk read overhead and shortens data processing time,making it have broad application prospects in large-scale computing applications such as machine learning and image processing.However,the performance of the Spark platform still needs to be improved.When a large number of tasks are processed simultaneously,Spark’s cache replacementmechanismcannot identify high-value data partitions,resulting inmemory resources not being fully utilized and affecting the performance of the Spark platform.To address the problem that Spark’s default cache replacement algorithm cannot accurately evaluate high-value data partitions,firstly the weight influence factors of data partitions are modeled and evaluated.Then,based on this weighted model,a cache replacement algorithm based on dynamic weighted data value is proposed,which takes into account hit rate and data difference.Better integration and usage strategies are implemented based on LRU(LeastRecentlyUsed).Theweight update algorithm updates the weight value when the data partition information changes,accurately measuring the importance of the partition in the current job;the cache removal algorithm clears partitions without useful values in the cache to releasememory resources;the weight replacement algorithm combines partition weights and partition information to replace RDD partitions when memory remaining space is insufficient.Finally,by setting up a Spark cluster environment,the algorithm proposed in this paper is experimentally verified.Experiments have shown that this algorithmcan effectively improve cache hit rate,enhance the performance of the platform,and reduce job execution time by 7.61%compared to existing improved algorithms.

考虑系统效能和风险的电网设备检修/退役策略协同优化方法

为提高电网设备检修和退役决策的科学性,提出了一种考虑系统效能和风险的设备检修/退役策略协同优化方法。首先分析了设备检修的故障率回退效应,并基于数据驱动建立BP神经网络模型对故障率曲线进行动态修正;其次从系统效能的角度分析检修与退役之间的交互影响,并提出综合成本投入和系统可靠性提升2种属性,其中成本指标包括设备投资成本、运行维护成本、故障成本、检修成本和折旧损失,可靠性指标则以系统期望缺供电量表示,进而基于前景理论,建立各指标的前景模型;然后以检修时间和退役更换时间为优化变量,以综合前景值最大为优化目标,以系统风险水平为约束建立检修/退役策略协同优化模型;最后采用遗传算法求解所提模型,并以某城市区域配电网的变压器设备为例,验证了所提方法的有效性。

绞吸船疏浚中粗砂时泥泵叶轮更换策略分析

大型绞吸船中粗砂输送泥泵叶轮磨损严重,导致泥泵性能下降、油耗增加,针对目前通过泥泵运行过程振动情况来判定叶轮更换时机的现状,分析泥泵不同磨损阶段工效变化特性,对比不同累计输送方量下泥泵更换的成本投入、产能提升和整体经济效益,为泥泵叶轮更换策略优化提供指导。结果表明,1000万m^(3)的工程在200万m^(3)时更换叶轮对比300万m^(3)时更换叶轮,其预计可节省80.1 t燃油;累计输送方量250万m^(3)时,建议达到300万m^(3)或报废后更换,该泥泵叶轮更换策略能显著降低施工成本、实现节能减排。

Mitochondrial transplantation strategies as potential therapeutics for central nervous system trauma

Mitochondria are essential cellular organelles critical for generating adenosine triphosphate for cellular homeostasis, as well as various mechanisms that can lead to both necrosis and apoptosis. The field of ＂mi- tochondrial medicine＂ is emerging in which injury/disease states are targeted therapeutically at the level of the mitochondrion, including specific antioxidants, bioenergetic substrate additions, and membrane uncoupling agents. Consequently, novel mitochondrial transplantation strategies represent a potentially multifactorial therapy leading to increased adenosine triphosphate production, decreased oxidative stress, mitochondrial DNA replacement, improved bioenergetics and tissue sparing. Herein, we describe briefly the history of mitochondrial transplantation and the various techniques used for both in vitro and in vivo delivery, the benefits associated with successful transference into both peripheral and central nervous system tissues, along with caveats and pitfalls that hinder the advancements of this novel therapeutic.

ECC:Edge Collaborative Caching Strategy for Differentiated Services Load-Balancing

Due to the explosion of network data traffic and IoT devices,edge servers are overloaded and slow to respond to the massive volume of online requests.A large number of studies have shown that edge caching can solve this problem effectively.This paper proposes a distributed edge collaborative caching mechanism for Internet online request services scenario.It solves the problem of large average access delay caused by unbalanced load of edge servers,meets users’differentiated service demands and improves user experience.In particular,the edge cache node selection algorithm is optimized,and a novel edge cache replacement strategy considering the differentiated user requests is proposed.This mechanism can shorten the response time to a large number of user requests.Experimental results show that,compared with the current advanced online edge caching algorithm,the proposed edge collaborative caching strategy in this paper can reduce the average response delay by 9%.It also increases the user utility by 4.5 times in differentiated service scenarios,and significantly reduces the time complexity of the edge caching algorithm.

面向轨迹数据查询优化的缓存机制研究

移动对象数据库(Moving object database,MOD)管理随着时间不断改变位置的空间对象,其已经在广泛的应用中被研究。尽管索引和查询算法等许多与MOD相关的技术已经被提出,但缓存管理仍然被忽略,这对于数据库性能至关重要。传统的缓存方法忽视了数据本身的时空特性,无法实现良好的性能。本文提出从缓存层面充分挖掘轨迹数据的查询性能,首先针对轨迹数据特有的存储结构和读写过程,设计了适合MOD的缓存访问机制;然后对于MOD系统中缺少与应用场景和访问模式相关的缓存策略问题,定制了缓存替换方法;最后开发了缓存管理工具MOCache,以可视化的形式动态跟踪查询语句结束后缓存状态的变化。通过实验表明本文提出的缓存替换策略与传统的策略相比,命中率提高到76.56%,缩短了查询时间,并且使用缓存工具监控历史状态信息,能够更加全面地反馈和分析性能问题。

心脏瓣膜置换术后急性肾损伤危险因素分析及干预策略

目的探讨体外循环心脏瓣膜置换术后发生急性肾损伤(AKI)的危险因素及干预策略。方法纳入患有心脏瓣膜病并进行体外循环心脏瓣膜置换手术的患者共106例。其中男性66例,女性40例,年龄43~72岁,平均年龄(57.8±10.9)岁。依据术后是否发生急性肾损伤分为AKI组和非AKI组,比较2组患者术前、术中、术后的临床资料,采用单因素分析和多因素logistic回归分析方法,探讨体外循环心脏瓣膜置换术后急性肾损伤的危险因素,以便尽早给予患者肾脏功能保护策略,改善预后。结果106例患者术后发生AKI 24例,AKI发生率22.64%,术后院内死亡2例,院内死亡率8.33%;非AKI组82例,院内死亡2例,院内死亡率2.43%,2组之间死亡率比较,差异有统计学意义(P<0.05)。单因素分析显示,年龄、术前血肌酐>130μmol/L、左室射血分数(LVEF)<45%、存在感染性心内膜炎(SIE)、同期行冠状动脉旁路移植术(CABG)、体外循环时间、手术时间、平均动脉压(MAP)<70 mmHg、尿量<0.5 mL/(kg·h)、肺部感染、低心排、术后菌血症是术后AKI的危险因素。多因素logistic回归分析显示,术前血肌酐>130μmol/L、LVEF<45%、合并SIE、体外循环时间>2 h、术中及术后低血压、低心排、术后菌血症是术后AKI的独立危险因素。结论术前血肌酐>130μmol/L、LVEF<45%、合并SIE、体外循环时间>2 h、术中及术后低血压、低心排、术后菌血症是术后AKI的独立危险因素,围术期积极采取干预策略可以降低术后AKI的发生,改善患者预后。

全髋置换术老年患者复苏室苏醒时间影响因素分析及其护理策略

目的分析全髋置换术老年手术患者复苏室苏醒时间的影响因素及护理策略。方法回顾性分析2019年6月至2021年12月于中山市中医院收治的196例行全髋置换术的老年患者临床资料,根据患者术后复苏室苏醒时间分为>60 min组和≤60 min组,比较两组患者术后并发症的发生情况,对两组患者临床资料进行单因素及多因素logistic回归分析,分析老年患者复苏室苏醒时间的影响因素,并制订护理策略。结果196例患者中,麻醉苏醒时间>60 min组38例,≤60 min组158例。麻醉苏醒时间>60 min组患者的恶心呕吐、低氧血症、低血压、术后意识障碍、非人为低体温、深静脉血栓形成、呼吸系统并发症发生率高于≤60 min组,差异有统计学意义(P<0.05)。单因素分析结果显示,两组间性别、年龄、体重指数(BMI)、心率、手术时长、麻醉时长、手术室温度、术中出血量、术中低体温及术后体温下降幅度比较,差异有统计学意义(P<0.05)。多因素logistic回归分析显示,性别(男性)、年龄、手术时长、麻醉时长、术中低体温及术后体温下降幅度为影响全髋置换术老年手术患者复苏室苏醒时间的危险因素,BMI和手术室温度为保护因素(P<0.05)。结论手术室护理过程应充分考虑影响患者麻醉苏醒时间的独立影响因素,缩短手术和麻醉时长,时刻留意手术室温度和患者的体温变化,及时进行调节,以缩短患者苏醒时间,减少术后不良并发症。

全髋关节置换术后恐动症影响因素分析及干预策略研究

目的:探讨全髋关节置换术(THR)后恐动症影响因素,并总结恐动症预防策略。方法:选取75例行THR患者分为2组,分析行THR后影响患者恐动症的独立高危因素。结果:恐动症组文化程度低于非恐动症组,病程长于非恐动症组,GSES得分、社会支持评定量表得分及CD-RISC得分低于非恐动症组(P<0.05);TSK评分与自我效能、社会支持以及心理弹性水平呈负相关(r=-0.755、-0.794、-0.745,P<0.001)。结论:文化程度低、病程长、自我效能差、社会支持低以及心理弹性低是THR后发生恐动症的独立危险因素,应该积极干预,减少术后恐动症发生率。

膝关节骨性关节炎人群康复机器人研究现状及发展趋势

随着社会老龄化的加快,膝关节骨性关节炎(Knee Osteoarthritis,KOA)发病趋于年轻化,其对社会和患者产生极大困扰。为有效抑制KOA病变,并对KOA关节置换术后康复提供辅助,各类运动支具和康复训练装置应运而生,其中,康复辅具在KOA人群的康复训练中发挥了重要作用。为更全面地研究康复机器人在KOA人群康复训练中的应用,在分析KOA人群不同发病阶段康复需求的基础上,综述了辅助下肢运动障碍人群进行康复训练的机器人在机构结构、控制等方面的研究现状;针对KOA人群的康复机器人关键技术进行了分析。这为未来KOA人群康复机器人的设计提供了理论依据。

新禁食禁饮管理方案对老年髋部骨折合并糖尿病患者髋关节置换术后的影响

目的:研究新禁食禁饮管理方案对老年髋部骨折合并糖尿病患者髋关节置换术后的影响。方法:选取2020年1月—2021年1月我院收治的192例择期实施髋关节置换术的老年糖尿病患者作为研究对象,按随机数字表法分为对照组和观察组,每组96例,对照组患者采用常规禁食禁饮方案(术前禁食12 h,禁饮4 h),观察组采用新型禁食禁饮管理方案(术前禁食6 h,禁饮2 h)。比较两组患者的手术相关指标,包括手术时间、出血量、输液量、住院时间、入住ICU病例数等,比较两组患者的血红蛋白和血糖水平,以及围手术期间不良反应发生率。结果:与对照组相比,观察组患者出血量更小,输液量更少,入住ICU病例也更少,住院时间更短,差异有统计学意义(P<0.05);观察组患者的血红蛋白水平高于对照组,血糖水平低于对照组(P<0.05);观察组的低血糖发生率低于对照组(6.25%vs 16.67%),差异有统计学意义;观察组各项不良反应发生率明显低于对照组,差异有统计学意义(P<0.05)。结论:对实施髋关节置换术的老年髋部骨折合并糖尿病患者采用术前禁食6 h,禁饮2 h的管理策略有利于改善患者手术效果,维持血糖水平,改善围手术期的血流动力学状态,降低术后不良反应发生率,具有重要的临床应用价值。

主动脉瓣狭窄患者经导管主动脉瓣置换术尺寸策略和手术结局分析

目的:旨在分享近几年接受接受经导管主动脉瓣置换术(transcatheter aortic valve replacement,TAVR)的症状性严重主动脉瓣狭窄(aortic stenosis,AS)患者的尺寸策略和手术结局。方法:2017年10月到2021年10月,在北京安贞医院接受TAVR术的132例严重AS患者进行回顾性评估,包括主动脉根部的解剖结构和形态及手术策略。“缩小尺寸”策略是在患者有复杂形态时实施的,例如二叶式主动脉瓣(bicuspid aortic valve,BiAV)、小叶水平严重钙化、小叶明显增厚和融合。将采用缩小尺寸策略的患者与采用瓣环尺寸策略的患者临床结果进行比较。结果:在132例患者中,41例(31.1%)为BiAV形态。根据TAVR手术策略,38例患者选择瓣环尺寸策略,94例患者选择缩小尺寸策略。缩小尺寸组BiAV患者比例更高(P=0.046)。主动脉根部的钙体积为449.9(243.2,782.2)mm^(3),主要分布在小叶水平上。TAVR术后1个月,主动脉瓣口面积(aortic orifice area,AVA)从(0.7±0.2)cm^(2)改善到(1.4±0.4)cm^(2),主动脉瓣跨瓣压差也明显降低,两组AVA、主动脉瓣跨瓣压差和中重度瓣周反流患者的百分比是相似的(P>0.05)。与瓣环尺寸策略组相比,采用缩小尺寸策略的患者装置成功率相似(74.5%vs.71.1%,P=0.687)。结论:中国TAVR患者具有更普遍的BiAV形态和严重的主动脉根钙负荷,更适合缩小尺寸策略。而缩小尺寸策略提供了与瓣环尺寸策略相比非劣势的装置成功率和假体血液动力学性能。

Semantic Cache Replacement Strategy for XML Algebra-Based Query Optimization

Aiming at the fact that traditional cache replacement strategy lacks pertinence to the semantic cache in the process of extensible markup language （XML） algebra query, a replacement strategy based on the semantic cache contribution value is proposed. First, pattern matching rules for XML algebra query and semantic caches are given. Second, the method of calculating the semantic cache contribution value is proposed. In XML documents with four different sizes, the experimental results of time efficiency show that this strategy supports environment of the XML algebra query and it has better time efficiency than both least frequency used （LFU） and least recently used （LRU）.

“以阀代井”水电站水轮机控制策略改进研究

近几年来,水电开发量与日俱增,众多具有长引水道的中小型水电站为了节省投资,选择使用调压阀代替调压井以应对大波动过渡过程,但设置调压阀并不能减少机组的水流惯性时间常数,会导致小波动过渡过程的动态特性较差。为了探寻改善“以阀代井”水电站水轮机调节系统小波动过渡过程动态特性的方法,对具有长有压引水道的常规水电站进行小波动扰动仿真,分析调节系统在小波动过渡过程中的动态响应。调节系统的动态响应结果表明,具有长有压引水道的常规水电站,其水轮机调节系统小波动过渡过程动态特性较差的原因是调速器动作过快导致接力器的响应速度和动作幅度过大。提出一种将接力器位移信号反馈至调速器的比例和微分环节的新型水轮机控制策略,通过抑制接力器动作的速度和幅度从而达到改善“以阀代井”水电站小波动过渡过程的动态性能。通过仿真对比,该方法确实能有效改善“以阀代井”水电站水轮机调节系统小波动过渡过程的动态性能。