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1.
为了采用小波变换提取心动周期信号(HPS)中的子信号,而分别对自愿受试者10名从卧位和站立体位采集心电信号。小波变换分解心动周期信号为一个细节成份和一个近似成份。对HPS、近似成份和细节成份都进行快速傅立叶变换,计算出了功率参数。心动周期信号的总功率从卧位到站住有显著的变化,近似成份的功率显著增加,细节成份的功率变化不明显,细节占总功率的比值显著变化。比较这两个体位的结果,其近似成份可能代表了史感神经系统的活动,而细节成份表达了副交感神经系统的调节。交感和副交感神经系统功能可分别由小波变换分解的2组成份的数字和图形参数作定量解释。  相似文献   

2.
为了采用小波变换提取心动周期信号(HPS)中的子信号,而分别对自愿受试者10名从卧位和站立体位采 集心电信号,小波变换分解心动周期信号为一个细节成份和一个近似成份对HPS近似成份和细节成份都进行 快速傅立叶变换,计算出了功率参数。心动周期信号的总功率从卧位到站位有显著的变化,近似成份的功率显著 增加,细节成份的功率变化不明显,细节占总功率的比值显著变化。比较这两个体位的结果,其近似成份可能代表 了交感神经系统的活动,而细节成份表达了副交感神经系统的调节。交感和副交感神经系统功能可分别由小波变 换分解的2组成份的数字和图形参数作定量解释。  相似文献   

3.
采用时域分析法、频域分析法对世居高原、亚高原、平原的90名高校非体育专业农村男学生进行心率变异性测试。结果表明:机体的交感神经调节功能随着海拔高度的增高呈现出先增强再降低的趋势;机体的副交感神经调节功能随着海拔高度的增高呈现出先降低再增高的趋势;机体自主神经的总体调节功能呈现出随着海拔高度增加而下降的趋势。  相似文献   

4.
目的研究植物神经系统对心血管功能的影响和作用.方法采用频谱分析的方法进行临床观察.结果给缺血性心脏病病人使用东莨菪硷贴剂24 h后,所有心率变异性参数均显著增加,缺血发作的频率及持续时间均减少.在急性心肌梗死时,频谱中所有的心率变异性指数(LF,HF,VLF和ULF4个区域)均呈典型性降低,其中标准差s<20ms时,致命性室性心律失常发生率显著升高,频谱图上不同的特征改变对心衰的判断预后亦有意义.心率变异性参数分析反映了心血管病人植物神经系统功能状态,副交感神经占优势时,则疾病趋于改善,而交感神经活性增强时则疾病预后不良.结论可将心率变异性的频谱分析法用于临床诊断及疾病的风险评价.  相似文献   

5.
IntroductionDrivingfatigue overloadinghas threatenedpeople s healthand life. Investigation datum from suggested that estimates ofthe contribution of driver mental fatigue to total trafficaccidents vary from 4% in 1980 to 25% in 1995[1]. Surveyresults revealed that 64% of respondents had experiencedfatigue on the road. In addition, 7% of the subject sampleclaimed to have had traffic accident due to fatigue.Drivingfatigue is a substantialproblem and serious threat inthe …  相似文献   

6.
Calcitonin gene-related peptide regulates calcium current in heart muscle   总被引:6,自引:0,他引:6  
K Ono  M Delay  T Nakajima  H Irisawa  W Giles 《Nature》1989,340(6236):721-724
The influx of Ca2+ due to the transmembrane calcium current, ICa, has a fundamental role in cardiac pacemaker activity, in the action potential plateau and in excitation-contraction coupling. Both sympathetic and parasympathetic neurotransmitters can modulate ICa. Recent studies indicate that in both the cardiovascular and the central nervous systems, nerve varicosities exist that contain a novel non-adrenergic, non-cholinergic peptide--calcitonin gene-related peptide (CGRP). Although CGRP is known to exert strong positive inotropic and chronotropic effects, as well as to cause vasodilation, very little is known about the ionic mechanisms of these effects. Here we report that CGRP dramatically increases ICa in single heart cells. Although this CGRP-induced increase in ICa resembles the effect of beta-adrenergic agonists, our results demonstrate some significant differences between the effects of CGRP and these agonists: (1) the increase due to CGRP cannot be blocked by beta-adrenergic antagonists; (2) the CGRP-induced effect is transient; and, (3) CGRP can inhibit isoproterenol-stimulated ICa. Our results provide the first electrophysiological evidence that CGRP can significantly modulate ICa in the heart, and suggest a new additional mechanism for the neurogenic control of cardiac function.  相似文献   

7.
Hein L  Altman JD  Kobilka BK 《Nature》1999,402(6758):181-184
The sympathetic nervous system regulates cardiovascular function by activating adrenergic receptors in the heart, blood vessels and kidney. Alpha2-adrenergic receptors are known to have a critical role in regulating neurotransmitter release from sympathetic nerves and from adrenergic neurons in the central nervous system; however, the individual roles of the three highly homologous alpha2-adrenergic-receptor subtypes (alpha2A, alpha2B, alpha2C) in this process are not known. We have now studied neurotransmitter release in mice in which the genes encoding the three alpha2-adrenergic-receptor subtypes were disrupted. Here we show that both the alpha2A- and alpha2C-subtypes are required for normal presynaptic control of transmitter release from sympathetic nerves in the heart and from central noradrenergic neurons. Alpha2A-adrenergic receptors inhibit transmitter release at high stimulation frequencies, whereas the alpha2C-subtype modulates neurotransmission at lower levels of nerve activity. Both low- and high-frequency regulation seem to be physiologically important, as mice lacking both alpha2A- and alpha2C-receptor subtypes have elevated plasma noradrenaline concentrations and develop cardiac hypertrophy with decreased left ventricular contractility by four months of age.  相似文献   

8.
Mental fatigue is an extremely sophisticated phenomenon, which is influenced by the environment, the state of health, vitality and the capability of recovery. A single parameter cannot fully describe it. In this paper, the effects of long time sustained low-workload visual display terminal (VDT) task on psychology are investigated by subjective self-reporting measures. Then power spectral indices of HRV, the P300 components based on visual oddball and wavelet packet parameters of EEG are combined to analyze the impacts of prolonged visual display terminal (VDT) activity on autonomic nervous system and central nervous system. Finally, wavelet packet parameters of EEG are extracted as the features of brain activity in different mental fatigue states. Kernel principal component analysis (KPCA) and support vector machine (SVM) are jointly applied to differentiate two states. The statistic results show that the level of both subjective sleepiness and fatigue increase significantly from pre-task to post-task, which indicate that the long time VDT task induces the mental fatigue to the subjects. The predominant activity of autonomic nervous system of subjects turns to the sympathetic activity from parasympathetic activity after the task. The P300 components and wavelet packet parameters of EEG are strongly related with mental fatigue. Moreover, the joint KPCA-SVM method is able to effectively reduce the dimensionality of the feature vectors, speed up the convergence in the training of SVM and achieve a high recognition accuracy (87%) of mental fatigue state. Multipsychophysiological measures and KPCA-SVM method could be a promising tool for the evaluation of mental fatigue.  相似文献   

9.
我国铅锌矿业可持续发展评价与预警系统研究   总被引:3,自引:0,他引:3  
对世界与我国1990~2006年铅锌产量、消费量和价格进行了详细调查,研究了我国铅锌矿业可持续发展的13个影响因素.采用模糊数学方法对我国铅锌矿业可持续发展进行了评价,并分析和预测了1990~2010年我国铅锌矿业可持续发展度(SDI).研究表明,1999年前我国铅矿业可持续发展度比较差,1999~2006年可持续发展持续向好,但随着我国铅资源保证程度下降,对国外资源依赖程度的增加和铅冶炼能力的过度扩张,我国铅矿业可持续发展度将下降,前景并不乐观;同时,1999年也是我国锌矿业可持续发展的分水岭,1999以前,我国锌矿业可持续发展度低于0.60,1999年后在0.70以上运行,预计2007~2010年我国锌矿业可持续发展度在0.74以上运行.根据可持续发展度,建立了我国铅锌矿业可持续发展预警系统.图2,表1,参8.  相似文献   

10.
J E Silva  P R Larsen 《Nature》1983,305(5936):712-713
There are several mechanisms by which homeothermic animals increase heat production, including shivering, sympathetic nervous system activation and stimulation of thyroid hormone secretion. Studies in rats have shown that increased sympathetic activity causes increased heat production in brown adipose tissue (BAT) after cold exposure or food ingestion. Acute cold exposure also increases circulating thyroid hormones which in turn stimulate cellular metabolism through induction of various enzymes. Most metabolic effects of thyroxine (T4) are thought to be due to the triiodothyronine (T3) which is produced from T4 by a process of 5' monodeiodination. There are two enzymes responsible for this reaction: type I, or propylthiouracil (PTU)-sensitive iodothyronine deiodinase (5'D-I), which is reduced in hypothyroidism, stimulated in hyperthyroidism and probably provides most of the circulating T3 in the adult rat. Type II 5'-deiodinase (5'D-II) is characteristic of brain and pituitary, is increased by thyroidectomy, is not inhibited by PTU and provides 50-80% of the intracellular T3 in these two tissues. Recently, 5'D-II activity was identified in interscapular BAT. As the sympathetic nervous system influences the metabolic activation of BAT, we have studied the effects of noradrenaline and acute cold exposure on BAT 5'D-II. We report here that both noradrenaline and cold exposure increase BAT 5'D-II through alpha 1-adrenergic receptors, whereas depletion of catecholamines with alpha-methyl-p-tyrosine (MPT) prevents the effect of cold but not that of noradrenaline. These results suggest that the sympathetic nervous system may increase T3 production in rats by stimulating BAT 5'D-II. By increasing metabolic rate, this rise in T3 would enhance the thermogenic response to sympathetic stimulation.  相似文献   

11.
本研究对24名青年受试者进行运动心肺功能测试,探索32式太极剑锻炼对青年男性心肺功能的影响。主要研究结论:长期32式太极剑运动可以促进运动后糖的恢复,改善能量消耗结构;还可以使控制心脏活动的迷走神经作用加强,交感神经的作用减弱,从而降低安静时心率,提高心室每搏输出量;实验组在32式太极剑锻炼中比对照组具有更高的运动心肺功能和能量消耗水平;运动中的指标大小更能体现长期练习32式太极剑对青年男子心肺机能、能量代谢等方面的改善作用。  相似文献   

12.
A nonlinear autoregressive (NAR) model is built to model the heartbeat interval time series and the optimum model degree is proposed to be taken to evaluate the nonlinearity degree of heart rate variability (HRV). A group of healthy persons are studied and the results indicate that this method can effectively get nonlinear information from short (6—7 min) heartbeat series and consequently reflect the degree of heart rate variability, which supplies convenience in clinical application. Finally, a comparison with the traditional time domain method shows that the NAR model method can reflect the complexity of the whole signal and lessen the influence of noise and instability, in the signal.  相似文献   

13.
外源镍在土壤中的存在形态及其与土壤酶活性的关系   总被引:6,自引:0,他引:6  
采用培养试验方法,研究了土壤中重金属镍的存在形态及其对5种土壤酶活性的影响.随着土壤外加镍的质量分数增加(100~1 600 mg/kg),碱性磷酸酶活性和酸性磷酸酶活性均受到较强的抑制,抑制率分别为15.0%~67.3%、13.9%~85.3%;脲酶活性抑制率为-1.6%~21.3%,表现出先激活后抑制的现象;镍对多酚氧化酶也有抑制作用;对过氧化氢酶的抑制作用轻微.研究结果表明,酸性磷酸酶、碱性磷酸酶和脲酶可作为判明土壤镍污染程度的主要生化指标.镍的存在形态与土壤酶活性之间的关联度分析和相关分析证实,DTPA提取的有效态镍与土壤酶活性之间相关性好、关联度大.因此,以DTPA提取的有效态镍来表征土壤镍的生物有效性是可行的.  相似文献   

14.
H C Hartzell  P F Méry  R Fischmeister  G Szabo 《Nature》1991,351(6327):573-576
The positive inotropic effect of the sympathetic nervous system on the heart is partly mediated by an increase in the voltage-gated Ca2+ current (ICa). This increase is generally attributed to beta-adrenergic receptor-stimulated cyclic AMP-dependent phosphorylation of the Ca2+ channel. It has been suggested that cAMP-dependent phosphorylation cannot explain all the effects of beta-adrenergic agonists on ICa and that a parallel membrane-delimited pathway involving the 'direct' action of the G protein Gs also stimulates ICa. A precedent exists for such a membrane-delimited pathway in the activation of a K+ channel by acetylcholine in heart. A membrane-delimited pathway for stimulation of ICa might be important in rapid beat-to-beat regulation of contraction by the sympathetic nervous system, because isoproterenol may produce a biphasic increase in ICa with the rapid phase (tau = 150 ms) putatively mediated by the direct pathway and the slow phase (tau = 35 s) by cAMP-dependent phosphorylation. Here we report that in frog, rat, and guinea pig ventricular myocytes ICa increases slowly and monophasically in response to isoproterenol. The increase is completely blocked by inhibitors of cAMP-dependent phosphorylation. Furthermore, the time course of the increase in ICa closely parallels the increase in contractile force produced by sympathetic nerve stimulation. These data refute earlier suggestions that regulation of Ca2+ channels by the sympathetic nervous system involves or requires a direct G-protein pathway.  相似文献   

15.
随着运动训练的进行,心脏植物神经功能会最为敏感地产生反应和适应,而应用心率变异性(HRV)分析方法可有效评价人体心脏植物神经功能。通过对篮球专项运动系和普通大学生各16名进行安静态心率变异性的时域和频域分析,观察篮球运动对心脏植物神经功能的影响,掌握运动员的身体机能状况。  相似文献   

16.
A E Cole  P Shinnick-Gallagher 《Nature》1984,307(5948):270-271
Slow muscarinic inhibition may be a powerful influence on membrane properties in the peripheral and central nervous system. But the location of the muscarinic receptors in sympathetic ganglia, either on interneurones or on the postganglionic membrane, and the underlying mechanism of the inhibitory response, remains controversial. In mammalian sympathetic ganglia synaptic activation of muscarinic receptors located on inhibitory interneurones was thought to release catecholamines leading to a membrane hyperpolarization called the slow inhibitory postsynaptic potential, or s.-i.p.s.p.. However, the s.-i.p.s.p. in parasympathetic ganglia and in amphibian sympathetic ganglia is due to direct monosynaptic activation of muscarinic receptors, accompanied by an increased potassium conductance (but see ref. 11), and is not mediated by catecholamines. The situation is less clear in mammalian sympathetic ganglia and monosynaptic s.-i.p.s.ps observed in other ganglia could be exceptions to the hypothesis. We showed earlier that the s.-i.p.s.p. in rabbit superior cervical ganglia is not affected by catecholamine antagonists. We now show that the s.-i.p.s.p. in a mammalian sympathetic ganglion is due to the monosynaptic activation of muscarinic receptors, probably by an increase in potassium conductance.  相似文献   

17.
研究了使用云模型理论智能诊断体震信号中心率异常信息的方法.利用云模型将定性的专家诊断体系与定量的计算机辅助诊断系统相结合,模拟了专家诊断过程.建立了心率异常智能诊断规则云模型,构造了体震信号JJ间期分布曲线图,以此自动校正模型参数,最终建立智能诊断机制.采用实验室搭建的体震信号实时采集系统提取2 000组样本作为采样对象,并与传统标准阈值法进行对比,验证了所提方法的可行性.实验结果表明:该方法自动聚类的准确率达到90.2%,高于传统方法 2个百分点.  相似文献   

18.
19.
【目的】采用不同砧木嫁接青钱柳,分析不同嫁接组合接穗和砧木生理指标的差异,探讨砧穗生理特性与嫁接成活的关系,为青钱柳砧穗嫁接亲和性的早期预测和砧木选择奠定基础。【方法】分别以枫杨(F)、薄壳山核桃(B)和青钱柳(Q)作为砧木嫁接青钱柳接穗(3种嫁接组合),采用切接的方法进行嫁接,测定嫁接后0、40、70 d各嫁接组合砧木和接穗的可溶性糖、可溶性蛋白、淀粉及单宁含量、过氧化物酶(POD)和多酚氧化酶(PPO)活性,并统计嫁接70 d后的成活率。【结果】青钱柳本砧嫁接成活率为53.49%,显著高于以枫杨和薄壳山核桃为砧木的嫁接组合。嫁接后随着时间的延长,本砧嫁接砧穗中的可溶性糖和淀粉含量均呈现先降低后升高的变化规律;3个嫁接组合单宁含量均表现为先升高后降低趋势,但本砧嫁接组合在两个时段均最低,QB组合均最高;3个嫁接组合砧穗POD活性均表现为先升后降;本砧嫁接砧穗PPO活性先降后升,而QF和QB组合砧穗PPO活性均持续升高。相关分析表明,40 d时测定的砧穗可溶性糖、淀粉、单宁含量及PPO活性与嫁接成活率呈显著负相关(P < 0.05),而POD活性与嫁接成活率呈显著正相关(P < 0.05);70 d时测定的砧穗可溶性糖、单宁含量和PPO活性与嫁接成活率呈显著负相关(P < 0.05),但接穗的POD活性与嫁接成活率呈极显著正相关(P < 0.01)。接穗与砧木的PPO和POD活性差值绝对值分别在40和70 d时与嫁接成活率均呈显著负相关(P < 0.05)。【结论】青钱柳本砧嫁接亲和性较强,而以枫杨和薄壳山核桃为砧木亲和性较弱,可溶性糖、淀粉、单宁含量、POD和PPO活性,以及POD和PPO活性差值绝对值可以作为青钱柳嫁接亲和性的早期评价指标。  相似文献   

20.
Equilibrium guanidinium chloride (GdmCl)-induced unfolding of arginine kinase (AK) was investigated by enzymatic activity, intrinsic fluorescence, 8-anilinonaphthalene-1-sulfonic acid (ANS) fluorescence, circular dichroism (CD) spectrum, and size-exclusion chromatography. The measurements showed that AK unfolded through two equilibrium intermediates: the molten globule state and the partly folded state. Both intermediates have no enzyme activity. The molten globule state exists at 0.4-0.8 mol/L GdmCi, perhaps after the N-terminal domain has unfolded but the C-terminal domain is still intact. The partly folded state occurs at 1.1-1.5 mol/L GdmCI with a hydrodynamic volume no more than 1.6-fold larger than the native state and a pronounced far UV-CD signal. Its ANS fluorescence intensity is about 50% of the molten globule state. This partly folded state shares similarities with the “burst” kinetic intermediate of protein folding.  相似文献   

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