State and output feedback design for robust tracking of linear systems with rate limited actuators

A design technique (Control of Uncertain Systems with Bounded Inputs, Tarbouriech S, Garcia G, (Eds), Lecture Notes in Control and Information Sciences, vol. 227 , Springer: Berlin, 1997; 173–186) recently proposed for stabilization of a linear system with rate‐limited actuators is utilized to design feedback laws that cause the system output to track a desired command signal. This design technique combines two design techniques recently developed for linear systems with position limited actuators, piecewise‐linear LQ control (Automatica, 1994; 30 : 403–416) and low‐and‐high gain feedback (IEEE Trans. Automat. Control, 1996; 41 : 368–378), and hence takes advantage of both design techniques, while avoiding their disadvantages. In the case that only the output is available for feedback, the performance of the state feedback law is preserved by the use of a fast observer. An open‐loop exponentially unstable fighter aircraft is used to demonstrate the effectiveness of the proposed control design method. Copyright © 2002 John Wiley & Sons, Ltd.     

罂硝软膏的制备及质量控制

目的 :制备罂硝软膏 ,并建立质量控制方法。方法 :以硝酸甘油、盐酸罂粟碱、双氯芬酸钾为主药研制软膏剂 ,用紫外分光光度法及酸碱滴定法分别测定硝酸甘油、盐酸罂粟碱、双氯芬酸钾3组分的含量。结果 :硝酸甘油、盐酸罂粟碱、双氯芬酸钾的平均回收率分别为100 65 %、99 86 %、100 55 %,相对标准差分别为0 4945 %、0 1719 %、0 3205 %(n=3)。结论 :该软膏制备工艺可行 ,质量可控 ,性质稳定。     

血糖水平对18F-FDG PET/CT图像质量的影响

目的 研究血糖水平对18F-脱氧葡萄糖(FDG) PET/CT图像质量的影响.方法 80例行体格检查或评价肿瘤性质的受检者,按空腹血糖水平分为9组(组间距为1mmol/L),第1组为血糖正常组,即血糖＜6.0mmol/L(10例);第2～9组血糖水平高于正常,分别为6.0～6.9mmol/L(11例),7.0～7.9mmol/L(13例),8.0～8.9mmol/L(11例),9.0～9.9mmol/L(11例),10.0～10.9mmol/L(8例),11.0～11.9mmol/L(6例),12.0～12.9mmol/L(5例),≥13.0mmol/L(5例).受检者做完PET/CT检查后,图像质量由2位有经验的医师独立判断.同时根据肝不同层面的标准摄取值(SUV)最大值(SUVmax)及SUV平均值(SUVavg)分别计算肝图像噪声.采用SPSS 12.0软件进行统计学处理.结果 (1)9组之间图像质量评分、肝噪声差异有统计学意义(P均＜0.05).将第2～9组图像质量评分、肝噪声分别与第1组进行比较,第2～7组与第1组差异无统计学意义(P均＞0.05);第8,9组与第1组比较差异有统计学意义(P均＜0.05),且评分低于第1组.(2)血糖水平与图像质量评分呈负相关(r=-0.52,P＜0.05);血糖水平与肝噪声呈正相关(SUVmax、SUVavgr值分别为0.33和0.60,P均＜0.05);SUVavg所算噪声与血糖水平的相关性优于SUVmax.结论 图像质量随血糖水平的升高而下降,血糖＜12.0mmol/L时与血糖正常者PET/CT图像质量差异无统计学意义,但当血糖水平≥12.0mmol/L时图像质量将显著下降.     

Prevalence of diabetic peripheral neuropathy and relation to glycemic control therapies at baseline in the BARI 2D cohort

Abstract   We evaluated the associations between glycemic therapies and prevalence of diabetic peripheral neuropathy (DPN) at baseline among participants in the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial on medical and revascularization therapies for coronary artery disease (CAD) and on insulin-sensitizing vs. insulin-providing treatments for diabetes. A total of 2,368 patients with type 2 diabetes and CAD was evaluated. DPN was defined as clinical examination score >2 using the Michigan Neuropathy Screening Instrument (MNSI). DPN odds ratios across different groups of glycemic therapy were evaluated by multiple logistic regression adjusted for multiple covariates including age, sex, hemoglobin A1c (HbA1c), and diabetes duration. Fifty-one percent of BARI 2D subjects with valid baseline characteristics and MNSI scores had DPN. After adjusting for all variables, use of insulin was significantly associated with DPN (OR = 1.57, 95% CI: 1.15–2.13). Patients on sulfonylurea (SU) or combination of SU/metformin (Met)/thiazolidinediones (TZD) had marginally higher rates of DPN than the Met/TZD group. This cross-sectional study in a cohort of patients with type 2 diabetes and CAD showed association of insulin use with higher DPN prevalence, independent of disease duration, glycemic control, and other characteristics. The causality between a glycemic control strategy and DPN cannot be evaluated in this cross-sectional study, but continued assessment of DPN and randomized therapies in BARI 2D trial may provide further explanations on the development of DPN.     

选择性肝血流阻断肝切除术的应用

目的探讨选择性肝血流阻断肝切除术的安全性和可行性。方法回顾性分析我院2002年3月至2006年10月行肝切除术65例,分为选择性肝血流阻断组（HVC,n=28）和第一肝门阻断组（Pringle,n=37）;比较两组病人术中出血量、手术时间、术后肝功能的恢复、术后两天的平均引流量以及术后并发症。结果两组病人术中出血量和手术时间均无显著性差异;HVC组术后3天和7天的血清谷丙转氨酶明显低于Pringle组,术后两天的平均引流量HVC组明显少于Pringle组;Pringle组有两例出现肝功能衰竭,其中1例死亡,HVC组没有肝功能衰竭及死亡病例。结论选择性肝血流阻断肝切除术安全、可行,较第一肝门阻断更有利于肝功能的恢复,减少肝功能衰竭的发生。     

激素间歇冲击及小剂量维持治疗IgA肾病的随机对照研究

目的:探讨激素间歇冲击及小剂量维持与血管紧张素转换酶抑制剂治疗中度蛋白尿IgA肾病的疗效及其影响因素。方法:47例IgA肾病患者随机分为实验组和对照组。对照组(21例)给予ACEI药物治疗,实验组(26例)在此基础上口服泼尼松0.5mg/kg,隔日给药,治疗12个月,并在治疗的第1、3、5个月初分别给予甲基泼尼松龙0.5g/d,冲击3d。对肾脏病理改变进行WHO分级并对各种病变进行半定量分析。结果:两组间在性别、年龄、临床及病理资料间无统计学差异。平均随访14个月后,实验组尿蛋白完全缓解8例(30.8%),部分缓解14例(53.8%),无缓解4例(15.4%);而对照组分别为4例(19.1%),3例(23.8%),12例(57.1%),有统计学差异(P<0.01)。治疗前后,实验组血肌酐分别为(89.9±30.3)μmol/L及(88.2±32.8)μmol/L;对照组分别为(89.5±37.9)μmol/L及(104.0±49.7)μmol/L,但两者比较均无统计学意义(P>0.05)。多因素分析显示疗效与肾小球硬化率及肾小管间质病变呈负相关。结论:激素间歇冲击及小剂量维持治疗能显著减少蛋白尿,维持肾功能稳定。影响疗效的主要因素为肾小球硬化率及肾小管间质病变程度。     

蚊虫的共生菌及其在媒介控制中的应用

许多昆虫与寄生在昆虫体表或肠道细胞中的微生物建立了共生关系。臭虫、蚜虫、猎蝽等昆虫可以依靠非最佳食物为生，这一是由于其特殊的生存环境，还由于其体内的共生微生物可以帮助合成和补充其食物中所缺乏的必需营养物质。蚊虫也与其肠道中共生细菌有着密切的联系。成蚊喜产卵于富舍细菌的水体中，水体细菌成为蚊虫幼虫的重要食物来源。伊蚊和库蚊幼虫正常生长发育不可缺少细菌，在无菌条件下饲养，蚊虫或其他媒介昆虫不能正常发育至成熟或不能传播人畜疾病。该文对蚊虫与细菌的共生现象以及其在以下几方面的应用进行综述，（1）蚊虫共生细菌的分离与鉴定，（2）共生细菌的形成与传代，（3）共生细菌在昆虫中的分布，并讨论了经过遗传改造的蚊虫共生细菌对蚊虫防治及控制疟疾等由昆虫传播的疾病的应用前景。     

Recovery profile of single motoneurons after electrical stimuli in man

The H-reflex of 120 soleus motoneurons was recorded using fibre EMG. The recovery profile of these motoneurons was studied during monitoring surface H-reflex records in 28 adult subjects. The spectrum of motoneurons tested was homogeneous with two extremes of neurons having different characteristics. A motoneuron population (forming about 69% of our sample) had a high threshold level for electrical stimuli, short recovery time, and short recovery fringe time (called type A). A second population of motoneurons (forming about 20-30% of our sample) had a low threshold level for electrical stimuli, long recovery fringe time (called type B). During an isometric muscle contraction every motoneuron showed an early shift in recovery time (i.e. each had a shorter recovery time) with shortened recovery fringe time. These changes were larger for motoneurons type B than motoneurons type A. With paired identical electrical stimuli of varying interstimulus intervals a motoneuron may fire in response to the conditioning and test stimuli giving an H2, but not in response to both stimuli. This occurred for interstimulus intervals of 4-11 ms. A strong inhibition period was recorded with interstimulus intervals of 12-80 ms in which all motoneurons did not show any recovery. Most motoneurons recovered in orderly fashion between 80 and 300 ms of interstimulus interval, and this recovery coincided with the fast recovery recorded in surface H-reflex. All motoneurons were recovered by 3000 ms of interstimulus intervals. These findings emphasize the importance of eliciting the H-reflex every 3-5 s in H-reflex methodology in order to be assured that all excited motoneurons have been recovered.