Optimal guaranteed cost stabilization of networked systems with bounded random packet losses

This paper is concerned with the optimal guaranteed cost stabilizing controller design problem for a class of networked control systems (NCSs) with random packet losses. The number of consecutive packet losses is assumed to be upper bounded, and the closed‐loop NCS is described as a discrete‐time stochastic delay system with a time‐varying input delay and a stochastic parameter. A sufficient condition is derived for the closed‐loop NCS to be exponentially stable and achieve an optimal guaranteed cost performance level. The relationships among the exponential decay rate, the guaranteed cost performance level, and two parameters characterizing the random packet losses, namely, the packet loss probability and the maximal number of consecutive packet losses, are simultaneously established in the obtained condition. Furthermore, design procedures for the state feedback stabilizing controllers are also presented. Finally, an illustrative example is given to show the effectiveness of the proposed results. Copyright © 2011 John Wiley & Sons, Ltd.     

bFGF微球对大鼠背部任意皮瓣存活的影响

目的：研究局部注射碱性成纤维细胞生长因子（bFGF）复合明胶微球对SD大鼠背部任意皮瓣存活的影响。方法：采用改良的乳化冷凝法交联制备复合bFGF明胶缓释微球,将其注射于大鼠背部任意皮瓣,24只SD大鼠随机分为bFGF微球组（A组）、bFGF治疗组（B组）和对照组（C组）,术后7天分别进行皮瓣存活率、新生血管计数的检测。结果：术后7天皮瓣的存活率分别为（65.42±2.19）%,（54.38±4.52）%,（45.43±2.71）%,微球组存活率显著高于对照组（P〈0.05）且存活质量最好;皮瓣内新生血管计数分别为28.75±2.36,21.28±3.82,18.68±5.44,具有显著性差异。结论：bFGF缓释微球可以促进缺血皮瓣的血管新生,提高皮瓣存活率。     

Risk factors for complications and in-hospital mortality: An analysis of 19,834 open pelvic ring fractures

BackgroundOpen pelvic fractures are rare injuries, associated with high patient morbidity and mortality. Few studies have investigated the impact of patient demographics, comorbidities, and injury related factors on complication and mortality rates. The purpose of this study was to: (1) identify the overall incidence of complications and mortality after open pelvic fractures, (2) compare patient factors between those who did and did not develop complications, (3) identify perioperative independent risk factors for complications and mortality.MethodsA query was performed for patients with open pelvic fractures between 2007 and 2017 using the American College of Surgeons National Trauma Data Bank. Patient and injury specific variables were collected and complications were identified using International Classification of Disease Ninth and Tenth edition Codes. Patient demographic and perioperative data was compared using Fisher’s exact test and chi-square test for categorical variables, and Welch’s t-test for continuous variables. Using pooled data from multiple imputations, logistic regressions were used to calculate odds ratios and confidence intervals of independent risk factors for complications.ResultsA total of 19,834 open pelvic fracture cases were identified, with 9622 patients (48.5%) developing at least one complication. Patients who developed complications were older (35.0 vs 38.1 years), and had higher Injury Severity Scores (17.7 vs 26.5), lower Glasgow Coma Scores (14.2 vs 11.7), and a larger proportion presenting with hypotension (21% vs 6.9%). After pooled regression involving 19 factors, these were the strongest independent predictors of inpatient complication and mortality.ConclusionWe report a mortality rate of 14%, with an inclusive complication rate of 48.5%. Evaluating risk factors for morbidity and mortality for this devastating orthopaedic injury provides knowledge of an inherently sparse population.Level of EvidenceLevel II, Retrospective study.     

FTIR-ATR结合膜富集技术测定中药材地龙中微量铜的含量

目的 利用傅里叶变换-衰减全反射红外光谱(FTIR-ATR)结合膜富集技术,建立中药材地龙中微量铜质量分数的快速、经济的测定方法.方法 首先,对30批校正集样品进行湿法消解,利用铜与金属络合剂1-(2-吡啶偶氮)-2-萘酚(PAN)发生络合反应,优化各种反应条件,包括pH 、PAN用量、反应时间.再将络合物抽滤富集在微孔滤膜上,采集其FTIR-ATR光谱,经9点平滑、一阶导数9点平滑等预处理后,利用随机森林回归算法建立其铜质量分数的定量校正模型.校正集按3∶1随机分配为训练集和测试集,对模型进行参数优化和评价.利用优化后模型预测广东、广西和福建3个产地地龙样品中铜的质量分数,并与ICP-MS测定结果进行比较.结果 最优模型预测3个产地地龙样品的质量分数在5.85～6.98 mg/kg之间,与ICP-MS分析结果相比,相对误差均小于20％.结论 本方法利用膜富集技术提高了FTIR-ATR的检测灵敏度,为中药材重金属元素的定量分析提供了一种新方法.     

基于深度表示的中医病历症状表型命名实体抽取研究

目的：命名实体识别在自然语言处理中是最基本的任务之一,本文通过应用深度表示的方法实现临床上的现病史数据的自动标识。方法：本文随机选取了10 426条现病史句子作为主要的文本研究对象,分别用词嵌入（word2vec）和网络结构特征（node2vec）两种构建向量的方法生成不同的词向量特征,再在基于条件随机场（Conditional Random Field,CRF）和结构化支持向量机（Structured Support Vector Machines,SSVM）的方法上进行十重交叉验证,计算并比较基于深度表示的症状表型命名实体抽取的性能。结果：传统的CRF算法的三个评价指标（准确率,召回率,F 值）为（0.888 9,0.786 9,0.834 8）;基于WENER方法下的CRF和SSVM的评价指标为（0.975 0,0.984 9,0.979 8）和（0.992 8,0.988 9,0.990 8）;在GENER方法下基于词的CRF和SSVM算法的三个评价指标为（0.972 8,0.976 8,0.975 2）和（0.983 3,0.974 5,0.978 8）;GENER方法下基于字的CRF和SSVM算法的评价指标为（0.927 8,0.862 8,0.887 9）和（0.943 7,0.946 8,0.941 3）。结论：深度表示的命名实体抽取算法性能要比传统的非深度表示的命名实体标识算法性能好。另外,通过比较深度表示的两种算法的性能后发现,无论是基于word2vec生成的词向量还是基于node2vec生成的词向量,SSVM模型算法性能均优于CRF算法的性能。     

SELEX技术的靶标范围拓展

靶标范围的不断拓展是指数式富集的配体系统进化(SELEX)技术和其他随机文库技术(如噬菌体表面展示技术等)的显著特征之一.经过20多年的发展,SELEX的靶标已经拓展到包括金属离子、各种有机小分子、药物、蛋白质等生物大分子、致病微生物、活细胞和组织等在内的多种形式,以细胞和组织为靶标的SELEX筛选策略在肿瘤靶向诊断和治疗的研究中也得到了初步应用,本文综述了SELEX技术的靶标拓展情况.     

使用随机森林判别分析法预测黑加仑油胶囊治疗高血脂的效果

目的:根据黑加仑油软胶囊进行的多中心开放Ⅳ期临床试验数据,预测其对不同患者治疗高血脂的效果。方法:选入30～80岁符合西医高脂血症诊断标准的患者,服用黑加仑油软胶囊6周,对符合方案完成试验的2 154例患者分析血脂变化情况,将数据分为训练集和测试集,建立随机森林(RF)预测模型,采用内部交叉验证和外部数据进行验证。结果:筛选出的主要预测变量有治疗前的中医证候得分、血清总胆固醇(TC)、甘油三酯(TG)、体质量指数(BMI)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)、病程、体重、血压、运动情况等。使用这些变量预测服药是否显效,交叉验证和外部验证的ROC曲线下面积(AUC)分别为0.827和0.857;按照外部验证数据最佳切点得到灵敏度和特异度分别为82.7%和72.8%,预测的正确率为77.9%。结论:黑加仑油软胶囊对高血脂证患者的治疗效果可以根据患者的病情、血脂水平、生命体征等情况进行预测,从而辅助临床决策。     

Risk factors for complications and in-hospital mortality: An analysis of 19,834 open pelvic ring fractures

BackgroundOpen pelvic fractures are rare injuries, associated with high patient morbidity and mortality. Few studies have investigated the impact of patient demographics, comorbidities, and injury related factors on complication and mortality rates. The purpose of this study was to: (1) identify the overall incidence of complications and mortality after open pelvic fractures, (2) compare patient factors between those who did and did not develop complications, (3) identify perioperative independent risk factors for complications and mortality.MethodsA query was performed for patients with open pelvic fractures between 2007 and 2017 using the American College of Surgeons National Trauma Data Bank. Patient and injury specific variables were collected and complications were identified using International Classification of Disease Ninth and Tenth edition Codes. Patient demographic and perioperative data was compared using Fisher’s exact test and chi-square test for categorical variables, and Welch’s t-test for continuous variables. Using pooled data from multiple imputations, logistic regressions were used to calculate odds ratios and confidence intervals of independent risk factors for complications.ResultsA total of 19,834 open pelvic fracture cases were identified, with 9622 patients (48.5%) developing at least one complication. Patients who developed complications were older (35.0 vs 38.1 years), and had higher Injury Severity Scores (17.7 vs 26.5), lower Glasgow Coma Scores (14.2 vs 11.7), and a larger proportion presenting with hypotension (21% vs 6.9%). After pooled regression involving 19 factors, these were the strongest independent predictors of inpatient complication and mortality.ConclusionWe report a mortality rate of 14%, with an inclusive complication rate of 48.5%. Evaluating risk factors for morbidity and mortality for this devastating orthopaedic injury provides knowledge of an inherently sparse population.Level of EvidenceLevel II, Retrospective study.