正常国人腰间盘纤维软骨粘弹性实验研究

研究了正常国人急性外伤致死的成人新鲜尸体10个腰间盘L3-4、14-5纤维软骨的力学性质。以一维拉伸的方法得出了L3-4、L4-5腰间盘纤维软骨的破坏载荷、伸长比、Lagrange张应力、Lagrange张应变等数据。以多项式，用回归分析方法得出椎间盘L3-4、L4-5纤维软骨的应力-应变关系表达式及应力-应变曲线。还对椎间盘L3-4、L4-5纤维软骨进行拉伸应力松弛、蠕变实验。得出了椎间盘L3-4、L4-5纤维软骨的归一化应力松弛函数、蠕变函数G(t)、J(t)表达式。以冯元桢教授的软组织大变形准线性理论，构建了L3-4、L4-5椎间盘纤维软骨的松弛函数K(λ，t)=G(t)T^(e)(λ)的表达式，对实验结果进行分析讨论。     

The Topography of Non-Linear Cortical Dynamics at Rest, in Mental Calculation and Moving Shape Perception

Differential cortical activation by cognitive processing was studied using dimensional complexity, a measure derived from nonlinear dynamics that indicates the degrees of freedom (complexity) of a dynamic system. We examined the EEG of 32 healthy subjects at rest, during a visually presented calculation task, and during a moving shape perception task. As a nonlinear measure of connectivity, the mutual dimension of selected electrode pairs was used. The first Lyapunov coefficient was also calculated. Data were tested for non-linearity using a surrogate data method and compared to spectral EEG measures (power, coherence). Surrogate data testing confirmed the presence of nonlinear structure in the data. Cognitive activation led to a highly significant rise in dimensional complexity. While both tasks activated central, parietal and temporal areas, mental arithmetic showed frontal activation and an activity maximum at T3, while the moving shape task led to occipital activation and a right parietal activity maximum. Analysis of mutual dimension showed activation of a bilateral temporal-right frontal network in calculation. The Lyapunov coefficent showed clear topographic variation, but was not significantly changed by mental tasks (p<.09). While dimensional complexity was almost unrelated to power values, nonlinear (mutual dimension) and linear (coherence) measures of connectivity shared up to 37% of variance. Data are interpreted in terms of increased cortical complexity as a result of recruitment of asynchronously active, distributed neuronal assemblies in cognition. The topography of nonlinear dynamics are related to neuropsychological and neuroimaging findings on mental calculation and moving shape perception.     

Correlation dimension analysis of the artificial circulation

Artificial circulation has been analyzed by decomposing it into parts. However, the sum of the decomposed parts is not equal to the whole system, especially in nonlinear dynamic systems such as biological systems. To evaluate prosthetic circulation as an entity, not as decomposed parts, nonlinear mathematical analytic techniques, including fractal dimension analyzing theory, were used. Two pneumatically actuated ventricular assist devices were implanted as biventricular bypasses (BVB) in chronic animal experiments using four healthy adult goats. For comparison between natural and prosthetic circulation in the same experimental animals, the BVB-type complete prosthetic circulation model with ventricular fibrillation was adopted. All hemodynamic parameters with natural and prosthetic circulation were recorded under awake conditions and calculated by a personal computer system. By the use of nonlinear mathematical techniques, time-series data of the hemodynamics were embedded into the phase space, and correlation dimension analysis was performed to evaluate the reconstructed attractor. Our results suggest that the correlation dimension of the arterial blood pressure does not linearly increase according to the increase of the embedding dimension, even during artificial circulation, suggesting those are the fractal time series data. Dimensional analysis of the hemodynamics revealed that lower dimensional fractal dynamics were observed during prosthetic circulation. Fractal time series data are suggested to have robustness and error resistance. Thus, our results suggest that the circulatory regulatory system with the artificial heart may have these desirable characteristics. Accepted: July 14, 1995     

Relative contribution of vertical,within-farm and between-farm transmission of Mycoplasma synoviae in layer pullet flocks

ABSTRACT

In this study, the relative contribution of vertical transmission, within-farm transmission and between-farm transmission of Mycoplasma synoviae in layer pullet flocks was quantified using logistic regression analysis. Data from 311 Dutch pullet flocks, of which 172 (55%) were positive for M. synoviae, were included in the study. Also the M. synoviae status of the parent stock of these flocks was included. The M. synoviae status was determined with the M. synoviae rapid plate agglutination test. Data analysis showed that vertical transmission was the most important transmission route for M. synoviae in layers as is demonstrated by an odds ratio of 5.8 (P?=?0.000). A positive association with M. synoviae infections was found for layer pullet flocks on a multi-house farm where at least one other flock was M. synoviae-positive compared to single-house farms (odds ratio 3.1, P?=?0.022), while a negative association was found when no other M. synoviae-positive flocks were present (odds ratio?=?0.2, P?=?0.003). No association was found between M. synoviae status of pullet flocks and poultry farm density. Odds ratios were 0.54 (P?=?0.288) and 0.34 (P?=?0.073), respectively, for medium and highest poultry farm density compared to lowest poultry farm density. This is the first time that the relative contribution of horizontal and vertical transmission of M. synoviae has been quantified. These results can be extrapolated to M. synoviae control in general, and emphasize the importance of M. synoviae control in parent stock and practical channelling.     

Mechanism of blood pressure elevation during angiotensin infusion

The mechanism of increased preload and its contribution to the rise in blood pressure during intravenous angiotensin infusion were studied in anesthetized dogs. In open-chest dogs angiotensin increased mean aortic blood pressure by 58±12 mmHg. Left ventricular end-diastolic dimension, measured as myocardial chord length (MCL) by ultrasonic technique, increased by 7±1 %. By inflating a balloon in the inferior vena cava, end-diastolic MCL was reduced to control value and the rise in mean aortic blood pressure was almost halved to 32±10 mmHg above control value. A similar preload effect was recorded in closed-chest dogs using end-diastolic left ventricular pressure as an estimate of left ventricular volume. During angiotensin infusion to the upper body only, end-diastolic MCL did not increase. When redistribution of the splanchnic blood volume was prevented, the effect of angiotensin on end-diastolic MCL was reduced to 1/3. Angiotensin reduced liver but not splenic dimension measured by ultrasonic technique. We conclude that about half of the rise in blood pressure during angiotensin infusion is due to increased end-diastolic volume caused by blood redistribution. About 2/3 of this increase in preload is due to redistribution from the splanchnic bed, mainly from the liver.     

基因组序列CGR图形表示的多重分形分析

为了更好地描述基因组序列CGR(chaos-game representation)图形的分形特征,引入多重分形理论进行分析。通过研究3种概率集对标度不变性范围的影响,选取出标度不变性最好的概率集,计算光滑的广义维数谱和多重分形谱。结果表明:以相对概率组成概率集时标度不变性最好,而且标度不变性随尺度变化可被分为3个不同的区域,这反映了基因组序列不同长度的序列片段有不同的分布规律。可见,多重分形方法可以用于描述基因组序列CGR图形的分形特征。     

局限性癫痫脑电时间序列的分形维数计算比较

为探索应用非线性动力学理论诊断癫痫病的新方法，对局限性癫痫病患者脑电时间序列进行了相关维数（Ｄｃ）和波形维数（Ｄｗ）的计算比较。观察到，痫性导联脑电的分形维数多低于对侧导联的值；相关维数Ｄｃ的相对变化量较波形维数Ｄｗ大；而波形维数Ｄｗ对痫性棘波敏感；结果提示，脑电时间序列的分形维数有可能成为诊断癫痫的特征参数，值得进一步深入研究。     

Examination of the Diagnostic Value and Estimation of the Chaos Phenomenon in Temporomandibular Joint Sounds Using Fractal Dimension

.The aim of this study is to estimate the chaos phenomenon in temporomandibular joints (TMJ) sound using fractal dimension (FD), and to examine the diagnostic value of the FD in comparing TMJ sounds produced by 6 asymptomatic and 25 symptomatic TMJ. Multiple mandibular opening and closing cycles recorded were used to calculate the waveform dimension and correlation dimension in the FD. Chaos in the TMJ sounds was estimated by the FD that was saturated with some constant value to an increase of embedding dimension. Results reveal that fractal analysis produces a high degree of reproducibility within, and similarity across subjects, and indicate that both FD values of the asymptomatic TMJ sounds are significantly higher than those of the symptomatic. These findings suggest that chaos is present in TMJ sounds and the difference in the FD is of diagnostic value in evaluation of pathological change in TMJ sound signals.     

大、中学生对文化维度的知觉

目的:考察大、中学生对文化维度的知觉的情况和发展趋势。方法:用Trandis编制的个人主义-集体主义量表(Individualism-Collectivism Scale)对1760名大、中学生进行测量。结果:大、中学生对文化维度的知觉存在年龄效应;随着年龄增加,对集体主义维度的知觉从42.05%下降到27.40%,而对个人主义维度的知觉从5.01%上升到18.58%;水平维度的知觉从47.06%下降到40.71%;垂直维度的知觉从4.14%上升到6.19%。结论:大、中学生对文化维度的知觉的差异主要表现在个人主义和集体主义的维度,水平维度和垂直维度有轻微的波动。     

Cortical projections arising from the basal forebrain: a study of cholinergic and noncholinergic components employing combined retrograde tracing and immunohistochemical localization of choline acetyltransferase

The neurochemical identity of ascending putative cholinergic pathways from the rat basal forebrain was investigated employing a method for simultaneously visualizing choline acetyltransferase immunoreactivity and retrogradely transported horseradish peroxidase-conjugated wheatgerm agglutinin. This histochemical procedure revealed three distinct populations of neurons: (1) cells which stained only for choline acetyltransferase immunoreactivity; (2) cells which stained only for retrograde tracer and (3) cells which stained simultaneously for choline acetyltransferase immunoreactivity and retrograde tracer. The results demonstrated that this projection is topographically organized and consists of both cholinergic and noncholinergic components. The relative contribution of each component varied with the telencephalic target area as follows: the olfactory bulb receives a projection from cells of the horizontal limb nucleus, 10-20% of which are cholinergic (Ch3); the hippocampal formation receives afferents from cells of the medial septal and vertical limb nuclei, 35-45% of which are cholinergic (Ch1 and Ch2); and the cortical mantle receives afferents primarily from cells within the substantia innominata-nucleus basalis complex, 80-90% of which are cholinergic (Ch4). The topographical organization of Ch4 projections is not as completely differentiated as we have previously observed in the primate.