七氟烷对术前化疗患者心肌细胞的影响

目的评价七氟烷对术前化疗患者心肌细胞的影响。方法择期拟行乳腺癌根治术全麻患者30例,ASAⅠ或Ⅱ级,依据术前是否化疗,分为化疗组（S组）15例和未化疗组（C组）15例,于麻醉前（T0）、手术结束（T1）、术后24h（T2）、术后48h（T3）时抽取患者颈内静脉血检测并比较血清肌酸肌酶（CK- MB）、心肌肌钙蛋白I（cTnI）和N端B型脑钠肽（NT- proBNP）水平。结果两组患者各时点CK- MB水平差异无统计学意义（P＞0.05）,与C组比较,S组各时点cTnI、NT- proBNP水平升高（P＜0.05）。两组内比较,与T0时刻相比,T1、T2、T3时刻cTnI和NT- proBNP水平差异均无统计学意义（均P＞0.05）。结论术前化疗对于心肌细胞有损伤,而对于术前化疗患者,七氟烷未加重心肌细胞损伤,可安全用于术前化疗患者麻醉。     

A modified heuristics-based model for simulating realistic pedestrian movement behavior

Pedestrian movement simulation models are used in various areas, such as building evacuation, transportation engineering, and safety management of large events. It also provides effective means to uncover underlying mechanisms of collective behaviors. In this work, a modified heuristics-based model is presented. In this model, the potential collisions in the moving process are explicitly considered. Meanwhile, a series of simulations is conducted in two typical scenarios to demonstrate the influence of critical parameters on model performance. It is found that when facing a wide obstacle in a corridor, the larger the visual radius, the earlier the pedestrian starts to make a detour. In addition, when a pedestrian observes a large crowd walking toward him, he chooses to make a detour and moves in the flow in a uniform direction. Furthermore, the model can reproduce the lane formation pedestrian flow phenomena in relatively high-density situations. With the increase of pedestrian visual radius and the weight of potential collision resistance, more stable pedestrian lanes and fewer moving-through-the-counterflow pedestrians can be observed. In terms of model validation, the density-speed relationship of simulation results accords well with that of the published empirical data. Our results demonstrate that the modified heuristics-based model can overcome the deficiency of the original model, and reproduce more realistic pedestrian movement behavior.