ATS in exposition

ATS (A Tutorial System) is written in $\text{APL}\text{360}$. It contains an author interrogation program that interviews the author in English and formats his tutorial for him, and a tutorial supervisor program that interfaces with the students. The supervisor program contains many features of machine intelligence (a knowledge of the rules of human discourse) which operate in every tutorial without intervention by the author, and provide the discourse with an aura of intelligent behavior. Certain aspects of both programs are illustrated by terminal examples.     

钩端螺旋体抗原表位预测、重组、表达及免疫原性分析

目的应用生物信息学方法预测两种钩端螺旋体外膜蛋白的表位，结合基因工程手段进行表位重组、表达和免疫原性分析。方法用预测程序ProPred和ANTIGENIC预测LipL32和OmpL1的表位，应用PCR技术合成重组表位基因片段，克隆PCR产物构建重组质粒，测序验证。在BL21（DE3）中诱导表达融合蛋白。纯化该融合蛋白，免疫BALB／c小鼠，显微镜凝集试验（MAT法）测定抗体效价。结果在LipL32和OmpL1中各预测到2个既具有MHC结合肽特性又具有B细胞表位特征的肽段。PCR合成的重组表位基因序列中没有出现移码和碱基置换。纯化后融合蛋白纯度〉90％。融合蛋白产生的抗体效价为75．79，融合头（运载蛋白）抗体效价为10．62。结论重组表位具有一定免疫原性。为相关蛋白的表位重组和亚单位疫苗等方面的研究打下了良好的基础。     

应用自编软件判断复合型酸碱平衡紊乱的体会

目的 研究自主开发的动脉血气分析软件用于判断复合性酸碱平衡紊乱的临床意义.方法 应用该软件分析80例患者的动脉血气资料并判断酸碱平衡紊乱的类型,同时应用代偿公式手工计算和通过Siggaard-Andersen酸碱平衡诊断图进行判断,比较三种方法判断结果的一致性、作出判断所费时间及判断酸碱平衡紊乱的效果.结果 ①电脑软件分析和手工计算判断酸碱平衡紊乱类型的符合率,正常和单纯性酸碱紊乱为100.0%,二重酸碱紊乱为82.4%(P＜0.05),三重酸碱紊乱为65.2%(P＜0.01).②电脑软件分析和应用Siggaard-Andersen酸碱平衡诊断图判断酸碱平衡紊乱类型的符合率,正常和单纯性酸碱紊乱为87.0%,二重酸碱紊乱为50.0%(P＜0.05),三重酸碱紊乱为0.0%.③应用软件对23例正常及单纯型酸碱紊乱组、34例二重酸碱紊乱组进行判断,所需时间分别为(8.0±1.0)s和(8.3±1.0)s,明显少于通过Siggaard-Andersen酸碱图判断时所需的(30.0±2.7)s和(33.5±3.2)s,及应用代偿公式手工计算作出判断所需的(23.4±5.5)s和(96.1±12.9)s,其差别均有极显著性(P＜0.001).④软件与Siggaard-Andersen酸碱图相结合判断酸碱紊乱类型,可以扩大酸碱图的使用范围.结论 应用该软件判断复合型酸碱紊乱准确性高、花费时间短,软件分析和Siggaard-Andersen酸碱图相结合有助于酸碱平衡紊乱的判断.     

Modelling the response of scalp sensory receptors to transcranial electrical stimulation

Transcranial electrical stimulation of the brain cause considerable discomfort to the patient. The purpose of the study was to find out whether this could be affected by the choice of stimulation parameters. A spherical volume conductor model of the head and active compartmental models of a pyramidal motor nerve and scalp nociceptor were used in combination to simulate the scalp nociception to transcranial electrical stimulation. Scalp nociceptors were excited at distances of several centimetres from the electrodes. The size of the excited scalp area correlated with the length of the stimulation pulse. The area was 12.3, 20.4 and 26.0 cm², for a 10μs, 100μs and 1 ms constant current pulse, respectively. With a 100 μs constant current pulse, the threshold for motor excitation was 205 mA and, for nociception, it was 51 mA. There was no significant difference between constant current and capacitor discharge pulses or between electrodes of different sizes. The results imply that the use of very short stimulation pulses can reduce the pain. If a topical anaesthesia is used to reduce the pain, it has to be applied on a large area around the electrodes.     

恒定梯度场磁共振成像脉冲序列研究

本研究提出了恒定梯度场下磁共振快速成像的方法。这种成像方法对磁体场强的要求不高 ( 15 0 0高斯 ) ,在相对较低的场强下具有成像速度快、对梯度场功放要求低、全开放设计等特点。本研究从磁体设计、射频脉冲波形、扩散效应几个方面进行了讨论 ,并提出了几种快速成像脉冲序列。最后给出了用计算机模拟的初步成像结果。     

人体运动过程中生理负荷强度的计算机Fuzzy调控

通过采用双输入，单输出的模糊调控模式和最大属度平均法进行了解模糊判别，以及列表值法等，对人体在运动过程中的生理负荷强度进行了实时调控，从而使整个Ｆｕｚｚｙ调控系统具有调控速度快，超调量小，以及稳定性和可靠性高的优点。     

Ring electrode for radio-frequency heating of the cornea: Modelling and<Emphasis Type="Italic">in vitro</Emphasis> experiments

Radio-frequency thermokeratoplasty (RF-TKP) is a technique used to reshape the cornea curvature by means of thermal lesions using radio-frequency currents. This curvature change allows refractive disorders such as hyperopia to be corrected. A new electrode with ring geometry is proposed for RF-TKP. It was designed to create a single thermal lesion with a full-circle shape. Finite element models were developed, and the temperature distributions in the cornea were analysed for different ring electrode characteristics. The computer results indicated that the maximum temperature in the cornea was located in the vicinity of the ring electrode outer perimeter, and that the lesions had a semi-torus shape. The results also indicated that the electrode thickness, electrode radius and electrode thermal conductivity had a significant influence on the temperature distributions. In addition,in vitro experiments were performed on rabbit eyes. At 5 W power, the lesions were fully circular. Some lesions showed non-uniform characteristics along their circular path. Lesion depth depended on heating duration (60% of corneal thickness for 20s, and 30% for 10s). The results suggest that the critical shrinkage temperature (55–63°C) was reached at the central stroma and along the entire circular path in all the cases.     

Variation of fractionator estimates and its prediction

 Over the last decade the so-called ’fractionator’ has become widespread in anatomical and pathological research for obtaining unbiased estimates of total numbers of particles in biological specimens. Several methods have been proposed for predicting the precision (i.e., the variation) of the estimated total numbers of particles using the fractionator (i.e., for predicting the precision of fractionator estimates). However, the validity of these predicting methods has not been tested so far. As it is impossible to do so with biological experiments, it was carried out here by using a computer simulation. Specimens containing particles, with various particle distributional patterns, were modeled, and the total number of particles in the specimens was estimated repeatedly with various modeled sampling schemes. It could be shown that the empirically estimated precision of the modeled fractionator estimates depend on both the particle distributional pattern in a modeled specimen as well as on the applied sampling scheme. Furthermore, considerable differences between the predicted and the empirically estimated precision of the modeled fractionator estimates were found. This was due partly to an incorrect assumption, which serves as the basis for one of the proposed predicting methods, partly to the fact that for some of the proposed predicting methods important contributions to the variation of fractionator estimates have not been considered, and partly to the fact that the mathematical theory, which serves as the basis for all predicting methods proposed so far, can in principle not be the optimum basis for predicting the precision of fractionator estimates. Based on the results of the computer simulation, a new, simple method is proposed for predicting the precision of fractionator estimates. Accepted: 28 April 1998     

Self-learning fuzzy control of atracurium-induced neuromuscular block during surgery

Self-learning fuzzy logic control has the important property of accommodating uncertain, non-linear and time-varying process characteristics. This intelligent control scheme starts with no fuzzy control rules and learns how to control each process presented to it in real time, without the need for detailed process modelling. A suitable medical application to investigate this control strategy is atracurium-induced neuromuscular block (NMB) of patients in the operating theatre. Here, the patient response exhibits high non-linearity, and individual patient dose requirements can vary five-fold during an operating procedure. A portable control system was developed to assess the clinical performance of a simplified self-learning fuzzy controller in this application. A Paragraph (Vital Signs) NMB device monitored T₁, the height of the first twitch in a train-of-four nerve stimulation mode. Using a T₁ setpoint=10% of baseline in ten patients undergoing general surgery, a mean T₁ error of 0.45% (SD=0.44%) is found while a 0.13–0.70 mg k⁻¹ h⁻¹ range in the mean atracurium infusion rate is accommodated. The result compares favourably with more complex and computationally-intensive model-based control strategies for the infusion of atracurium.     

血栓多普勒信号的计算机仿真研究

利用超声多普勒技术检测血栓,对临床诊断有十分积极的意义。为了研究多普勒信号特征提取方法检测血栓的性能,在计算机上生成仿真的血栓多普勒信号,仿真的参数,如血栓半径、血栓进入采样容积的时间等参数可事先设定,通过分析、研究不同给定参数的仿真信号,证实了利用超声多普勒技术无损检测血栓的可行性,并提出了表征血栓多普勒信号的敏感参数。