An experimentally supported, mathematical explanation of the gas chromatographic elution behaviour of the long-chain carbon members of the homologous series

By substituting the saturated vapour phase tension of the pure normal hydrocarbons described by the Clausius-Clapeyron law into the accepted expression of the specific retention volume (V_g,T), a theoretically coherent and relatively simple mathematical evidence of the elution behaviour of the homologous members has been deduced. It gives exponential retention time dependence on carbon number for isothermal, and nearly equidistant (i.e., approximately linear retention-time dependence on carbon number) elution for linear temperature programmed gas chromatographic runs. The final equations are in close correlation with the experimental results. Special emphasis is placed on the fact that a good approximation—not strict physical laws—have been found.     

充气温控毯用于神经外科手术患者的控温效果

目的评价充气温控毯用于神经外科手术患者的控温效果。方法40例择期行平卧位脑肿瘤切除术患者,年龄16—65岁,体重41-72 kg,ASAⅠ-Ⅲ级,随机分为2组(n=20):A组,术中充气温控毯24℃风档进行降温,肿瘤切除完毕前30 min进行复温;B组,术中充气温控毯维持中心温度正常(35．2—36．60℃)。均采用气管内静吸复合麻醉,静脉注射异丙酚1．5～2 mg／kg、芬太尼4-6μg／kg、维库溴铵0．1～0．2 mg／kg诱导,吸入0．6％-1．2％异氟醚维持;吸入氧浓度40％;异丙酚1．5～2 mg·kg-1·h-1持续输注;维库溴铵1～2 mg间断静脉注射。每5分钟记录1次中心温度(鼻咽温),观察围术期不良反应及并发症。结果A组2例患者因手术时间超过24 h剔除,共38例进行统计。A组患者降温速率(1．11±0．05)℃／h,复温速率(0．74±0．09)℃／h。A组患者89％(16/18)在硬脑膜打开前达到目标温度34℃,平台期平均中心温度(34．3±0．5)℃,距34℃最大升幅0．52℃,最大降幅为0．23℃。A组患者67％(12／18)手术结束时中心温度恢复正常。返回ICU后A组患者中心温度(返回ICU时实测温度的均值)(35．8±0．6)℃低于B组(36．6±0．4)℃(P<0．05)。A组患者4例术后出现寒颤、3例发热、1例死亡。结论神经外科手术中应用充气温控毯可较理想地降低体温,相对于降温效率其复温效率偏低。     

Effects of acute administration of d-amphetamine and haloperidol on procedural learning in man

The effects of an indirect dopamine-agonist, d-amphetamine, and a non-selective dopamine receptor antagonist, haloperidol, were investigated in normal male volunteers using a between-subjects double-blind design in a procedural learning task, thought mainly to involve unconscious/automatic learning. The results showed: (1) d-amphetamine facilitated response speed, whereas haloperidol inhibited it, in comparison to placebo; (2) the linear increase in procedural learning corresponded with pharmacological manipulation of degree of dopaminergic activity, i.e. subjects given haloperidol showed the least, and subjects given d-amphetamine the greatest, procedural learning. The implications of these findings are discussed in relation to investigation of abnormalities of procedural learning processes in schizophrenia. Received: 28 June 1996/Final version: 2 October 1996     

Proposed new bladder volume monitoring device based on impedance measurement

A new implantable bladder volume-monitoring device based on the impedance measurement of the detrusor muscle is described. The system is completely autonomous and forms a mixed-signal (analogue/digital) feedback loop with a neuro-stimulator to rectify bladder dysfunctions (incontinence and retention) through neuromuscular stimulation techniques. A programmable instrumentation amplifier and a signal processing block, to eliminate the artefacts caused by the patient’s movements, have been designed and tested. The layout for the signal processing block has been realised in 0.8 μm BiCMOS technology.     

Attentional demands of continuously monitoring orientation using vestibular information.

The aim of this series of experiments was to determine whether attention is normally required for continuously processing vestibular information concerning orientation, or is required only when orientation is disrupted (eg by vestibular dysfunction or by conflicting visual and vestibular orientation cues). In the first two studies, healthy subjects were passively oscillated, and indicated when they perceived they were passing through their starting position. There was only weak evidence for interference between performance on this 'continuous orientation monitoring task' and on concurrent mental tasks. However, a third study showed that when patients with vestibular imbalance carried out the continuous orientation monitoring task their performance on a concurrent mental arithmetic task was substantially impaired. This dual task interference was correlated with inaccuracy in judging orientation on the continuous orientation monitoring task, which in turn correlated with severity of recent vestibular symptomatology (assessed by questionnaire). In a fourth experiment, disorientation was induced in healthy subjects by rotating the visual field about the line of sight. Bidirectional interference was observed between monitoring orientation (assessed by accuracy in setting a rod to the perceived vertical) and performance of an arithmetic task. Dual task interference was correlated with baseline levels of disorientation induced by the visual field, as indicated by inaccuracy in judging the visual vertical. These findings suggest that monitoring orientation makes significant demands upon cortical processing resources when disorientation is induced, whether the disorientation results from deficient sensory functioning or from ambiguous perceptual information.     

Phase-constrained data extrapolation method for reduction of truncation artifacts

The authors present an improvement to a sigma-filter extrapolation method for the reconstruction of magnetic resonance (MR) images from symmetric discrete Fourier data. By making use of the phase information in the image data, the proposed method can overcome the data inconsistency problem of the original method for handling MR image data with large phase variations, such as those obtained in gradient-echo pulse sequences. Reconstruction results show that its performance is comparable with that of the modified complex sigma-filter method proposed previously to handle the inconsistency problem. However, the new approach has the advantage of reducing computation time by a factor of two with use of a sigma filter applied to real instead of complex images. It is expected that this method will be more practical for use in clinical MR imaging systems.     

低分子量聚合物电解质的合成与性能

研究了低分子量梳状聚合物电解质的合成方法及结构，性能。首先合成了不同分子量的甲基丙烯酸聚乙二醇单甲醚酯，并进一步合成了分子量一万左右的梳状聚合物电解质，结果表明：反应严格按照反应方程进行，精制产物是非晶的梳状聚合物，本聚合物体系均存在两个玻璃化转变温度，一个在100℃左右，归属为梳状聚合物主链的玻璃化转变，另一个在－20摄氏度以下，归属于侧链玻璃化转变，在室温下侧链可以运动，有利于电活性物质的迁移和扩散，并用超微电极研究了该电解质的行为。     

捻转补泻手法针刺合谷穴对其局部皮肤温度的影响

目的阐明针刺捻转补法与泻法的操作是否存在效应上的差异,并探讨其效应差异是否为补泻效应的差异.方法应用红外线热像技术,采用不同的捻转补泻手法针刺健康人合谷穴后,观察其在即刻,10、20、30min,对局部皮肤温度的影响.结果不同捻转补法与泻法的操作存在着不同程度的效应差异,其中补法可以使皮温升高,泻法可以使皮温降低,以石氏捻转补泻针法较为明显.结论1)补泻手法,补法和泻法的操作可产生不同的效应.2)不同捻转补泻手法对皮肤温度产生的升降效应为补泻效应,其中以石氏捻转补泻手法最为明显.3)证明补泻手法实施的必要性.     

多级图像对比度放大技术在膝关节摄影中的应用

目的:分析评价膝关节摄影中多级图像对比度放大技术(MUSICA)参数设定的成像效果,为实际临床应用提供理论指导。方法:随机抽取膝关节侧位软拷贝图像70例,以骨皮质、骨小梁、肌间隙、髌上囊、皮下脂肪为比对目标,由三位观察者对其显示情况进行分析,并对结果进行统计分析。结果:MUSICA处于较小值(0～2)时,适合于软组织显示,但图像锐利度欠缺;处于较高值时(4～6)适合于观察骨皮质、小梁等细节信息,但较多地出现伪影,共25例;处于2～4时整体影像对比度适中,如实反映人体密度结构。结论:作图像处理时应将MUSICA为2～4设定为常规,实际应用通常情况下可以选择该处理方法,但应根据具体要求适当调整MUSICA参数值。     

应用电子计算机计算血液流变学的正常值及分析

为评价血流粘滞诸因素生理与病理的异常,对济南地区338例正常人血液流变学的各项指标进行了检测,统计了血液流变学各项指标的总平均及男女的平均值和正常范围,并计算了血液流变学各项指标间的相关系数。