苯胺加氢反应过程的多变量解耦广义预测控制

针对苯胺加氢间歇反应具有高度不确定性和交叉耦合性,传统PID控制器很难达到理想控制品质,本文采用阶梯控制策略设计多变量广义预测控制(GPC)解耦控制系统。首先针对系统的交叉耦合性,对目标函数解耦算法进行了简化设计以有效减少计算量;然后利用GPC策略构建一个双输入双输出解耦GPC系统;最后将多变量解耦GPC控制与传统PID变结构控制进行对比分析,模拟仿真效果验证了该控制系统的有效性和强鲁棒性。     

邹城市儿童常规免疫接种情况调查

[目的]了解现阶段儿童常规免疫接种率及其影响因素,进一步推动儿童计划免疫持续、深入地发展。[方法]按容量比例概率抽样（PPS）法,调查630名2001年1月1日至2003年12月31日出生儿童的“四苗”及乙肝疫苗接种情况。[结果]“四苗”全程合格接种率为95．48％,乙肝疫苗首针及时接种率为92．06％。不合格接种原因：超期接种占54．13％。99．68％的儿童都是到预防接种门诊进行接种。[结论]邹城市计划免疫“四苗”及乙肝疫苗接种率均保持在较高水平,规范化接种门诊建设效果显著,已进入新的发展阶段。     

The response of the isolated ductus arteriosus to transmural stimulation and drugs

1 Responses of isolated ductus arteriosus preparations from near term guinea-pigs and lambs to transmural electrical stimulation and drugs were studied in a low oxygen medium (Po₂ 19 to 28 mmHg).

2 Acetylcholine and noradrenaline contracted both vessels in a dose-dependent manner, their threshold being between 10^-8 and 10^-7 M. Transmural stimulation (pulse width 0.2 to 0.6 ms, typically 20 Hz) also contracted the vessels.

3 Atropine and phentolamine or dibenzyline selectively blocked responses to acetylcholine and noradrenaline, respectively.

4 In the guinea-pig ductus, part of the response to transmural stimulation was due to activation of intrinsic adrenergic nerves since the responses were reduced by α-adrenoceptor antagonists, bretylium or prior reserpine treatment, but not by atropine. The response of the lamp ductus to transmural stimulation varied greatly in magnitude and was inconsistently affected by α-adrenoceptor blocking drugs.

5 There was no evidence that transmural stimulation activated cholinergic nerves in either species.

6 After inactivation of α-adrenoceptors with dibenzyline, noradrenaline caused a β-adrenoceptor-mediated relaxation. Both this effect and isoprenaline-mediated relaxation were blocked by propranolol. β-Adrenoceptor activity was more prominent in the ductus of the guinea-pig than of the lamb.

7 Raising the Po₂ from 19-28 to 92-98 mmHg increased the response of the guinea-pig ductus to transmural stimulation suggesting that, in this species, physiological elevation of oxygen tension at birth may increase transmitter release from intrinsic adrenergic nerves. Whether this mechanism would contribute to ductus closure remains an open question.

8 We postulate that β-adrenoceptor-mediated relaxation has a role in maintaining ductus patency in the guinea-pig foetus.

     

Growth hormone 24-h serum profiles during pregnancy—lack of pulsatility for the secretion of the placental variant

Summary. Serum profiles of growth hormone (GW) were recorded for 24 h in women at different stages of normal pregnancy. Two monoclonal antibodies directcd against different epitopes and unaffected by human placental lactogen were used in radioimmunoassays to distinguish the pituitary 22K-GH from the placental GH variant. The 'normal' episodic peak activity of GH in non-pregnant and first trimester pregnant women was dramatically changed into a continuous very stable secretion during late pregnancy. This change was first observed at 17 weeks gestation. It is concluded that during the second half of pregnancy, serum measurements of GH reflect a major contribution from a non-cpisodically secreted placental GH variant and a concomitant suppression of pituitary GH. This specific signal, i.e. a continuous GH secretion, may be an important regulator of maternal liver metabolism during pregnancy.     

Cover Picture: Macromol. Chem. Phys. 18/2005

Summary: We show that small quantities of dibenzylidene sorbitol dispersed in poly(ε‐caprolactone) coupled with shear flow provide a self‐assembling nanoscale framework to yield high levels of crystal orientation. During modest shear flow of the melt, the additive forms highly extended nanofibrils which adopt a preferred alignment with respect to the flow field, and on cooling polymer crystallisation is directed by these fibrils. We use in situ time‐resolving SAXS and WAXS techniques to explore how this behaviour can be modified by the composition, the shear rate and strain as well as the temperature at which the shear flow is imposed. SAXS studies show that the 3% DBS completely dissolves in the PCL melt at temperatures ≥120 °C and that any shear flow imposed at temperatures above such values is ineffective in directing crystallisation.

SAXS pattern of crystallized PCL after cooling.     

Behavioral Response in the Terrestrial Isopod <Emphasis Type="Italic">Porcellio scaber</Emphasis> (Crustacea) Offered a Choice of Uncontaminated and Cadmium-Contaminated Food

The objective of this study was to find out whether Porcellio scaber discriminates against Cd-contaminated food. The foraging behavior in animals offered uncontaminated and Cd-contaminated food simultaneously was quantified for 48-h employing computer-aided video tracking. To see whether the isopods’ selection of less contaminated food could diminish the influence Cd on food consumption, growth, metal assimilation, moulting and mortality, Cd-dosed food (20, 45, 200 and 450 mg kg⁻¹ dry weight) was offered together with untreated food for 3 weeks. Data from the video tracking experiments revealed that animals visited Cd-dosed food as often as untreated food, but spent much less time near Cd-dosed food. Discrimination against Cd-contaminated food increased with previous experience with contaminated food and/or with increased Cd body burden. In 3 weeks exposure uncontaminated food preference rose with time of exposure and cadmium concentration in food and reached a maximal preference ratio of 65% (untreated food): 35% (Cd-dosed food). The decreased consumption of Cd-dosed food was compensated by the increased consumption of control food. Cadmium body burden increased with time of exposure and cadmium concentration in food consumed, while the influence of Cd on food consumption, growth and moulting was diminished.     

Elimination of Non-Viable cells by DNase Treatment Prior to Lymphocytotoxicity Test

An enzymatic method for removal of non-viable cells from lymphocyte suspensions prior to HL-A typing is described. It involves treatment of the suspensions with the enzyme Deoxyribonuclease (DNase), which does not seem to alter the HL-A antigens on the viable cells. The method is easy to perform, and the conventional microlymphocytotoxicity test can be applied for the HL-A typing.