A Stable Q Compensated Reverse Time Migration Method Based on Excitation Amplitude Imaging Condition

The stability and efficiency, especially the stability, are generally concerned issues in Q compensated reverse time migration (Q-RTM). The instability occurs because of the exponentially boosted high frequency ambient noise during the forward or backward seismic wavefield propagation. The regularization and low-pass filtering methods are two effective strategies to control the instability of the wave propagation in Q-RTM. However, the regularization parameters are determined experimentally, and the wavefield cannot be recovered accurately. The low-pass filtering method cannot balance the selection of cutoff frequency for varying Q values, and may damage the effective signals, especially when the signal-to-noise ratio (SNR) of the seismic data is low, the Q-RTM will be a highly unstable process. In order to achieve the purpose of stability, the selection of cutoff frequency will be small enough, which can cause great damage to the effective high frequency signals. In this paper, we present a stable Q-RTM algorithm based on the excitation amplitude imaging condition, which can compensate both the amplitude attenuation and phase dispersion. Unlike the existing Q-RTM algorithms enlarging the amplitude, the exponentially attenuated seismic wavefield will be used during both the forward and backward wavefield propagation of Q-RTM. Therefore, the new Q-RTM algorithm is relative stable, even for the low SNR seismic data. In order to show the accuracy and stability of our stable Q-RTM algorithm clearly, an example based on Graben model will be illustrated. Then, a realistic BP gas chimney model further demonstrates that the proposed method enjoys good stability and anti-noise performance compared with the traditional Q-RTM with amplitude amplification. Compare the Q-RTM images of these two models to the reference images obtained by the acoustic RTM with acoustic seismic data, the new Q-RTM results match the reference images quite well. The proposed method is also tested using a field seismic data, the result shows the effectiveness of our proposed method.     

Delivery during extracorporeal membrane oxygenation (ECMO) support of pregnant woman with severe respiratory distress syndrome caused by influenza: a case report and review of the literature

Objective: To report a case of labour induction during extracorporeal membrane oxygenation (ECMO) support in a patient with acute respiratory distress syndrome (ARDS) caused by influenza and review of the literature.

Methods: Case report and the literature search of all English articles on delivery while on ECMO in patients with ARDS caused by influenza.

Results: A 25-year-old pregnant woman was initiated with ECMO due to severe ARDS caused by influenza A (H1N1) virus. When the patient had symptoms of colporrhagia and uterine contractions, the medical team decided to start labour induction while on ECMO. There were in total five case reports identified. Maternal oxygenation was improved after delivery and ECMO was successfully discontinued.

Conclusions: Maternal oxygenation was improved after delivery, which may be beneficial to reduce the duration of ECMO. Caesarean section (CS) may be the most used mode and labour induction could be another option. The procedure should be performed by an experienced ECMO team, cooperating with the obstetrician, anaesthesiologist, and ICU doctors.     

不同强度运动对大鼠心脏降钙素基因相关肽的影响

目的:探讨不同强度运动训练对降钙素基因相关肽(CGRP)在心脏组织中表达的影响及其作用机制。方法:将60只SD大鼠随机分为对照组(C组)、小强度运动组(LE组)、中等强度运动组(ME组)和大强度运动组(HE组),每组15只。建立8周不同强度运动训练动物模型,采用免疫组织化学法和计算机图像分析技术,对大鼠心脏形态结构进行观察,并进行心脏CGRP免疫组化分析。结果:8周小强度运动后,大鼠心脏CGRP表达较对照组变化不明显;8周中等强度运动后,大鼠心脏CGRP表达较对照组显著增加(P<0.05),HE染色、HBFP染色和变色酸2R亮绿染色显示心肌组织形态结构无明显改变,仅心肌纤维有轻度缺血缺氧改变;8周大强度运动后,大鼠心脏CGRP表达较对照组显著减少(P<0.05),HE染色、HBFP染色和变色酸2R亮绿染色显示心肌形态结构发生改变并存在明显的缺血缺氧损伤。结果表明,长期中等强度运动使心脏CGRP表达增加,改善了冠状循环和心肌血液供应,对心肌细胞具有保护作用;长期大强度运动使心脏CGRP对心肌细胞的保护作用减弱,可能是导致心肌发生缺血缺氧性损伤的重要原因之一。     

微板紫外速率法漏检高值ALT标本一例

谷丙氨基转移酶（Alanine asninotrasferase，ALT）检测是采供血机构血液必检项目之一，ALT检测作为早期肝病诊断的一项非特异性指标，有助于鉴别与输血相关肝炎病毒携带者，同时可以在一定程度上弥补某些肝炎病毒标志物未被检测及“窗口期”的缺陷，有助于预防输血相关肝炎的传播。我血站实验室采用微板为载体的方法进行血清ALT检测：微板紫外速率法为初检方法；微板丙酮酸氧化酶法为复检方法。在检测过程中一例高值ALT血样，微板紫外速率法检测结果为6．6U／L，出现假阴性结果造成漏检，现报告如下：     

室上性心动过速导管消融治疗的新认识

导管消融治疗室上性心动过速(室上速)由于有95%以上的成功率及极低的并发症,成为目前治疗室上速的一线方法。随着心电生理学的进展,室上速电生理机制及治疗方法仍在不断改善。这些新的标测技术和消融方法的进步又进一步提高了治疗手术的成功率。现将近些年室上速消融治疗的一些新认识简述如下。1房室结折返性心动过速(AVNRT)的导管消融治疗房室结折返性心动过速是最常见的室上速之一。传统的理论认为房室结内存在快、慢2个径路,AVNRT时折返环局限在房室结内。这一理论的最有力的支持证据是在AVNRT时心房的激动可以与心动过速分离,由此…     

瘀祛补肾法治疗前列腺增生症46例

我院在1998年6月～2004年6月采用瘀祛补肾法治疗前列腺增生症46例,现总结如下.     

氯米帕明和米氮平治疗抑郁症的疗效比较

目的比较氯米帕明和米氮平治疗抑郁症的疗效。方法80例门诊抑郁症患者随机分为氯米帕明和米氮平治疗组,疗程8周,用汉密尔顿抑郁量表(HAMD),临床疗效总评量表(CGI)和副反应症状量表(TESS)在治疗前及治疗后第2、4、8周末行评定。结果治疗8周后氯米帕明组和米氮平组HAMD减分率分别为71．89%和71．74%,两组治疗前、后比较差异均有显著性(P＜0．01),但两组间比较差异无显著性(P＞0．05)。氯米帕明副反应发生率33．25%,米氮平22．21%两组间比较差异有显著性(P＜0．05)。结论米氮平治疗抑郁症疗效与氯米帕明相当,副反应轻。