下腔静脉滤器血栓形成局部置管溶栓与外周静脉溶栓治疗的比较

目的对比局部置管溶栓和外周静脉溶栓治疗在下腔静脉滤器血栓形成中的溶栓疗效,缩短滤器植入时间,提高滤器取出率,降低滤器永久植入后中远期合并症。方法采用单中心前瞻性研究的方法,收集2013年2月至2014年8月期间北京积水潭医院血管外科收治的创伤性下肢骨折合并深静脉血栓并放置可回收性腔静脉滤器(Opt Ease)的患者,下腔静脉造影或彩超发现滤器下血栓≥1.0 cm者,采用随机数字表法分组,进行外周溶栓或导管溶栓治疗,对滤器的取出率进行对比分析讨论。结果外周溶栓组30例,滤器取出11例,取出率36.7%,导管溶栓组30例,滤器取出24例,取出率80.0%,导管溶栓组取出率明显高于外周溶栓取出率(P<0.05);两组间溶栓治疗后血栓大小变化的对比,导管溶栓组的溶栓效果优于外周溶栓组(P<0.05)。滤器取出后无再发肺栓塞表现。结论在下腔静脉滤器血栓形成中局部置管溶栓效果明显优于外周静脉溶栓治疗。     

湖南省郴州市一起新型冠状病毒肺炎聚集性疫情流行病学调查

目的 通过分析郴州市一起新冠肺炎聚集性疫情相关病例发病确诊过程,探讨新冠病例早发现、早报告以及病例诊断和隔离观察解除的策略依据。 方法 对该起新冠肺炎聚集性疫情的病例和密切接触者进行现场流行病学调查,描述性分析流行病学史、临床和实验室资料。 结果 利用大数据比对监测,在转送监测对象至集中场所隔离医学观察时发现了新冠肺炎确诊病例何某华,由此发现一起新冠肺炎家庭聚集性疫情,何某的5名密切接触者中有3人发病确诊（包含1名重症病例）,其中重症病例黄某第7次新型冠状病毒核酸检测阳性进而确诊,密切接触者中胡某有流行病学史、血常规白细胞下降和肺炎影像学改变,但是5次咽拭子核酸检测阴性,未确诊。 结论 大数据比对监测对发现传染病有积极作用;早期对有流行病学史人员单独隔离医学观察对防止聚集性疫情发生有重要意义;将2次核酸检测阴性作为新冠肺炎病例的排除标准和将核酸检测阳性作为确诊新冠肺炎病例的必备条件,值得探讨,这都可能放走传染源,导致新冠肺炎传播。     

Frequency selectivity without resonance in a fluid waveguide

This study analyzes a waveguide consisting of two parallel fluid-filled chambers connected by a narrow slit that is spanned by two coupled elastic beams. A stiffness gradient exists in the longitudinal direction. This simple linear system, which contains no lumped mass, is shown to act as a spectral analyzer. Fluid waves traveling in the waveguide exhibit a distinct amplitude peak at a longitudinal location that varies systematically with frequency. The peaking is not based on resonance, but entirely on wave dispersion. When entering its peak region, the wave undergoes a sharp deceleration associated with a transition in which two propagation modes exchange roles. It is proposed that this mode shape swapping underlies the frequency analysis of the mammalian cochlea.In this study I explore the following question: How can a waveguide act as a spectral analyzer which spatially separates the frequency components of a wideband input? This question has been debated since Bekesy''s observation of traveling waves in the mammalian inner ear (1), the cochlea. On their way from base to apex, these fluid waves exhibit an amplitude peak at a frequency-dependent place. The peaking underlies our ability to identify and separate sounds.The most common explanation of cochlear frequency selectivity invokes local resonances coupled to the traveling wave (2). This approach requires a form of mass loading of the cochlear partition in addition to the mass loading by the surrounding fluid. The amount of mass needed in such models has been criticized for being unrealistically large given the cochlear anatomy (3). Even when sidestepping these objections, it has proved difficult to formulate models that reproduce both the amplitude and phase data of sensitive cochleae. On their way to the amplitude peak, cochlear traveling waves accumulate only 1–2 cycles (4, 5). Resonance-based models that produce sharp amplitude peaking tend to systematically overestimate the phase accumulation (6, 7). The resonance point acts as a cutoff, and a hypothetical frictionless wave would accumulate an infinite number of cycles when approaching it (8). Although damping will temper this singular behavior, too much of it also spoils the amplitude peaking.In active cochlear models (9, 10) this problem is circumvented by postulating a limited region of mechanical amplification (“negative damping”) basal to the resonance point. This creates a sufficiently sharp amplitude peak at a more basal location (safely away from the singularity), while still allowing ordinary damping to temper the phase accumulation near the resonance point (7).The present study explores an alternative approach which rejects resonance as the mechanism producing the peaking. In this scenario the peaking of traveling waves is created by a form of wave dispersion that is characterized by a steep deceleration of the energy transport. The deceleration produces a densification (focusing) of the energy that creates the peaking. This approach was motivated by neural data revealing a steep deceleration of cochlear waves near their peak (5, 11). Rather than building an elaborate biophysical model, the aim was to find the simplest possible fluid waveguide exhibiting steep deceleration and peaking.     

Robust fault detection filter design for a class of neutral‐type neural networks with time‐varying discrete and unbounded distributed delays

This paper is concerned with the problem of robust fault detection filter design for a class of neutral‐type neural networks with time‐varying discrete and unbounded distributed delays. A Luenberger‐type observer is designed for monitoring fault. By introducing an appropriate Lyapunov–Krasovskii functional and by using Jensen's inequality techniques to deal with its derivative, a new sufficient condition for the existence of robust fault detection filter is proposed in the form of LMIs with nonlinear constraints. To solve the nonlinear problem, a cone complementarity linearization algorithm is proposed. In addition, several numerical examples are provided to illustrate the applicability of the proposed approach. Copyright © 2012 John Wiley & Sons, Ltd.     

体外循环动脉微栓过滤器性能离体实验研究

目的:通过离体实验评价成人型动脉滤器(QUART)、米道斯动脉滤器(MEDOS)和宁波动脉微栓滤器的跨滤器压差和气泡去除能力。方法:分别选用QUART、MEDOS和宁波3种动脉过滤器各15个,依次为QG组、MG组和NG组,连接模拟体外循环管路,使用1 000 mL0.9%氯化钠预充环路,并在管路上连接Stockert气泡捕捉器。同时在动脉滤器的入口端、出口端和排气管处连接电子测压仪,使用管钳维持动脉滤器出口处压力为80 mmHg(1 mmHg=0.133 kPa),测定动脉滤器入口端、出口端和排气管处的压力。在流量为5.0 L/min时,于动脉滤器入口处每隔1 min加入10 mL空气,最多不超过80mL。结果:预充后NG组中9个(9/15,60.0%)动脉微栓滤器发出报警音,明显高于QG组和MG组,差异具有统计学意义(P<0.05);首次倒排时,QG、MG和NG组分别有1/15(6.7%)、13/15(86.7%)和15/15(100.0%)发出报警音,QG组明显低于MG组和NG组,差异具有统计学意义(P<0.05)。随着主泵流量的增加,3种动脉滤器入口端压力、出口端压力及压差均逐渐升高。相同流量下,3种动脉滤器入口端压力、出口端压力和压差差异均无统计学意义(P>0.05);流量为5 L/min,3组动脉滤器分别加入气体至80 mL时均未发出报警音。结论:使用动脉滤器时,排气需要2遍以上,才能安全使用。正常转机流量下,3种动脉滤器跨滤器压差基本相同。3种动脉滤器均有较强的气泡隔离能力。     

可回收式下腔静脉滤器预防肺栓塞临床效果分析

目的评价可回收式下腔静脉滤器(IVCF)在预防下肢深静脉血栓(DVT)导致肺栓塞中的的临床作用。方法46例下肢深静脉血栓形成患者为预防肺栓塞置入可回收式下腔静脉滤器,随访观察无滤器并发症发生及肺栓塞的出现。结果35例在放置12～14天取出,11例患者因滤器周围血栓形成,下腔静脉置管溶栓5～7天,5例血栓消失,滤器成功回收,另6例溶栓效果不佳,长期留置滤器。在取出的40例中,12例肉眼可见絮状血栓。结论下腔静脉滤器置入术能安全、有效预防肺栓塞,是治疗下肢深静脉血栓的重要方法之一。     

Inferior Vena Cava Filter Evaluation and Management for the Diagnostic Radiologist: A Comprehensive Review Including Inferior Vena Cava Filter-Related Complications and PRESERVE Trial Filters

Inferior vena cava filters are commonly encountered devices on diagnostic imaging that were highlighted in a 2010 Food and Drug Administration safety advisory regarding their complications from long-term implantation. The Predicting the Safety and Effectiveness of Inferior Vena Cava Filters (PRESERVE) trial is an ongoing after-market study investigating the safety and utility of commonly utilized filters in practice today. While most of these filters are safe, prompt recognition and management of any filter-associated complication is imperative to prevent or reduce the morbidity and mortality associated with them. This review is aimed at discussing the appropriate utilization and placement of inferior vena cava filters in addition to the recognition of filter-associated complications on cross-sectional imaging. An overview of the PRESRVE trial filters is also provided to understand each filter's propensity for specific complications.