内容简介
Sciences Under Space Conditions describes the interaction of gravity with neuronal systems. To deliver the basic scientific and technological background, the structures of neuronal systems are described and platforms for gravity research are presented. The book is rounded off by information about the interaction of chemical model systems with gravity and some simulations, and results about the interaction of gravity with neuronal systems from single molecules to the entire human brain are demonstrated. This is the first book to give a complete overview about neurophysiological research under conditions of variable gravity.
The book is intended for scientists in the field of space research, neurophysiology, and those who are interested in the control of non-linear systems by small external forces.
作者简介
Dr. Meike Wiedemann and Dr. Florian P.M. Kohn are Biological Scientists in the Lab of Membranephysiology at the University of Hohenheim, Germany and have been working in the field of life sciences under space condition for some years. Prof. Harald Roesner has been working in the field of Neurophysiology and is now retired. Prof. Wolfgang R.L. Hanke is the leader of the Department of Membranephysiology at the University of Hohenheim.
内页插图
目录
Chapter I Introduction
1.1 Historical remarks
1.1. Gravitational research
1.2 Excitable media and their control by small external forces
1.3 Waves and oscillations in biological systems
1.4 Book layout
References
Chapter 2 Gravity
2.1 Physical remarks
2.2 Perception of gravity by living systems
References
Chapter 3 Basic Structure of Neuronal Systems
References
Chapter 4 Platforms for Gravitational Research
4.1 Microgravity platforms
4.1.1 Short term platforms
4.1.2 Long term platforms
4.1.3 Magnetic levitation
4.2 Removing orientation
4.2.1 Clinostats
4.2.2 Random positioning machine
4.3 Macro-gravity platforms
4.3.1 Centrifuge
References
Chapter 5 A Model Systems for Gravity Research: The Belousov-Zhabotinsky Reaction
5.1 Setup for the Belousov-Zhabotinsky experiments
5.2 Preparation of gels for the Belousov-Zhabotinsky reaction
5.3 Data evaluation
References
Chapter 6 Interaction of Gravity with Molecules and
Membranes
6.1 Bilayer experiments
6.1.1 Hardware for the Microba mission
6.1.2 Hardware for the drop-tower
6.1.3 Hardware for parabolic flights
6.1.4 Hardware for laboratory centrifuge
6.1.5 Experimental results
6.2 Patch-clamp experiments
6.2.1 Principles of patch-clamp experiments
6.2.2 Hardware for the drop-tower
6.2.3 First hardware for parabolic flights
6.2.4 For the drop-tower
6.2.5 First parabolic flight experiment
6.2.6 Second hardware for parabolic flights
6.2.7 Second parabolic flight experiment
6.2.8 First results and future perspectives
References
Chapter 7 Behavior of Action Potentials Under Variable Gravity Conditions
7.1 Introductory remarks
7.2 Materials and methods
7.3 Isolated leech neuron experiments
7.4 Earthworm and nerve fiber experiments (rats and worms)
7.5 Discussion
References
Chapter 8 Fluorescence and Light Scatter Experiments to Investigate Cell Properues at Microgravity
8.1 Fluorescence measurements to determine calcium influx and membrane potential changes
8.1.1 Intracellular calcium concentration experiments
8.1.2 Membrane potential experiments
8.2 Light scatter experiments to determine changes in cell size
8.2.1 Static light scatter
8.2.2 Dynamic light scatter
References
Chapter 9 Spreading Depression: A Self-organized Excitation Depression Wave in Different Gravity Conditions
9.1 The retinal spreading depression
9.2 Gravity platforms used for retinal spreading depression experiments
9.2.1 Methods Contents
9.2.2 Experiment setup and protocol for spreading depression experiments in parabolic flights
9.2.3 Experiment setup and protocol for spreading depression experiments on TEXUS sounding rocket
9.2.4 Setup and protocol for spreading depression experiments in the centrifuge
9.2.5 Data analysis
9.3 Results
9.3.1 Spreading depression experiments in parabolic flights and in the centrifuge
9.3.2 Spreading depression experiments on sounding rockets and in the centrifuge
9.3.3 Determination of latency of spreading depression waves in the centrifuge
9.3.4 Summary of all spreading depression experiments on different gravity platforms
9.4 Discussion
9.4.1 Comment on different gravity platforms
References
Chapter 10 The Brain Itself in Zero-g
10.1 Methods
10.1.1 Slow cortical potentials (SCP)
10.1.2 Classical frequency bands in EEG
10.1.3 Peripheral psycho physiological parameters
10.1.4 Protocol and data analysis
10.1.5 Subjects
10.1.6 Ethic
10.2 Results
10.2.1 Slow Cortical Potentials (SCP)
10.2.2 Frequency band EEG
10.2.3 Peripheral stress parameters
10.3 Discussion
10.3.1 Slow cortical potentials
10.3.2 Frequency band EEG
10.3.3 Peripheral parameters
10.4 Conclusion
References
Chapter 11 Effects of Altered Gravity on the Actin and Mierotubule Cytoskeleton, Cell Migration and Neurite Outgrowth
11.1 Summary
11.2 Introductory remarks
11.3 Material and methods
11.3.1 Cell transfection
11.3.2 Cell culture and experiments with SH-SY5Y neuroblastoma cells
11.3.3 Cell migration experiments- Human carcinoma cell lines
11.3.4 Scratch Migration Assay (SMA)
11.3.5 Neurite outgrowth experiments-Primary cell culture of embryonic chicken spinal cord neurons
11.3.6 Imunostaining of cells
11.3.7 Staining of F-actin
11.3.8 Microscopy and live imaging
11.4 Results and discussion
11.4.1 Effects of altered gravity on actin-driven lamellar protrusion of SH-SY5Y neuroblastoma cells
11.4.2 Effect of altered gravity on the microtubule cytoskeleton of SH-SY5Y neuroblastoma cells
11.4.3 Effects of altered gravity on cell migration
11.4.4 Effects of altered gravity on the intensity and direction of neurite outgrowth
References
Chapter 12 Discussion and Perspectives
References
Index
精彩书摘
The question, which can be the cellular and further consequences of a higher open state probability is not that simple to be answered and will depend on the ion-channel under investigation. Up to now, only data for some specialized cases (model systems) are available, which are not to be applied to neuronal systems. However, let us speculate about the membrane of a neuron, having at least potassium channels to give the resting membrane potential and sodium channel to en- able action potentials (Hille, 1992; Weiss, 1997). The sodium channels are closed at rest; the potassium channels are permanently open at a non-zero open state probability. In a simplified discussion, closed sodium-channels would not be affected by gravity as the gating mechanism is of electrical nature, a depolarization of membrane across a threshold value. However, potassium channels as being open anyhow, would react to gravity changes, applying microgravity would lower their open state probability. Having the Goldman equation in mind (Weiss, 1997) this would lead to a membrane depolarization. As long as the threshold for sodium channels is not reached, no action potentials would be elicited, but further stimulation would more easily give an action potential.
The next set of experiments which has to be taken into account then is those with spontaneously spiking neurons. A prediction from the above statements (speculations) would be that in this case the spike frequency should be higher at microgravity. Just that has been shown. Also, a direct measurement of membrane potential should result in less negative values. In the experiments utilizing voltage sensitive dyes accurately this has been shown. According to textbook knowledge (Hille, 1992), at depolarization of membrane potential, voltage sensitive calcium channels open in the cell membrane, calcium enters the cell, and the intracellular calcium concentration increases. This could not be verified, in some experiments instead it was shown that the intracellular calcium level at microgravity drops (see above). As the intracellular calcium concentration is a highly regulated value, this could be due to secondary effects, but will have again to be investigated more deeply.
复杂系统的自发秩序与结构演化:跨尺度视角下的动力学机制 本书概要 本书深入探讨了复杂系统中自组织现象与斑图形成的普适性动力学原理,并着重考察了这些现象在不同空间和时间尺度上如何涌现与演化。我们聚焦于如何从基本的相互作用单元出发,理解宏观结构和有序状态的形成过程,而非局限于单一学科的具体模型。全书构建了一个跨越物理学、化学、生物学和信息科学的统一理论框架,用以描述和预测复杂系统在非平衡态下的行为模式。 第一部分:复杂系统动力学的基本概念与热力学基础 本部分奠定了理解自组织现象的理论基石。首先,我们从统计力学的角度审视了开放系统与耗散系统中的热力学性质。不同于平衡态下的熵增定律,本书详细阐述了远离平衡态的结构如何通过能量和物质的持续交换来维持其低熵状态,即“耗散结构”的形成条件。 我们详细分析了控制复杂系统行为的非线性动力学方程。从洛伦兹吸引子到更普遍的迟滞现象,非线性项如何导致系统对初始条件的敏感依赖性(混沌)和确定性行为中的随机性。通过深入研究分岔理论,我们揭示了系统参数微小变化如何引发拓扑结构上的突变,从而导致新的宏观有序状态的出现。特别地,我们引入了“临界现象”的概念,探讨了系统在相变点附近,涨落如何被放大并主导宏观尺度的集体行为。 第二部分:空间结构与时间周期性的涌现 本部分的核心在于分析空间和时间维度上的有序模式是如何在无序背景中自发产生的。我们从反应-扩散系统入手,这是描述斑图形成问题的经典模型。详细解析了图灵机制(Turing mechanism)的数学基础,即通过具有不同扩散速率和相互作用强度的组分之间的负反馈环路,实现稳定空间结构的形成。我们不仅重述了经典的反应-扩散模型,更拓展到具有非局部相互作用和时滞效应的变种,探讨它们如何生成更复杂、非周期的空间构型,如螺旋波、行波解和蜂窝状结构。 在时间动力学方面,本书重点研究了振荡与同步现象。我们分析了具有内在周期性的单元如何通过相互耦合,从随机振荡过渡到高度相干的集体节律。这包括对化学振荡器(如Belousov-Zhabotinsky反应)的动力学分析,以及在耦合振荡网络中如何形成相位锁定和波动的传播。我们还讨论了时空斑图——例如行进波和旋转激发波——的稳定性、速度以及它们在限制性几何结构(如弯曲表面或管道)中的传播特性。 第三部分:信息、尺度与层次结构 复杂系统的显著特征之一是信息在不同层次间的编码和传递。本部分将视角提升到信息论和网络科学的层面。我们采用图论工具来描述系统中的相互作用网络,探讨网络的拓扑结构(如无标度网络、小世界网络)如何影响信息的全局传播效率和鲁棒性。 我们深入研究了“涌现”(Emergence)的本质。涌现性指系统整体行为无法从其单个组成部分的简单叠加中预测。本书通过信息压缩和有效场论的方法,尝试量化不同尺度间信息流的损失与重构,旨在建立描述从微观动力学到宏观集体行为的规范转化规则。我们还考察了“尺度不变性”和“重整化群”的思想在描述跨尺度现象中的应用,强调了某些动力学规律在不同放大倍数下保持不变的内在原因。 第四部分:跨学科应用与新挑战 在最后一部分,我们将理论框架应用于几个关键的跨学科领域,展示自组织和斑图动力学的普遍性。 在材料科学中,我们讨论了液态晶体、自组装分子结构以及在外部场作用下形成周期性纳米结构的案例,重点分析了界面能和边界条件对最终宏观形貌的决定作用。 在流体力学中,我们探讨了湍流的起源和结构。湍流被视为一种高度复杂的、多尺度的耗散结构,我们使用涡旋理论和统计矩分析来描述其能量级联过程。 在生态学和模式形成领域,本书分析了种群分布的斑图形成,例如动物皮毛上的斑点和条纹图案,以及生态系统中物种的空间隔离现象,将其归因于不同物种间的竞争扩散平衡。 本书最后提出当前研究面临的前沿挑战,包括如何有效地模拟和控制高维、高非线性的复杂系统,以及在涉及复杂反馈和学习机制的系统中,如何从动力学角度理解自适应和演化过程。我们的目标是为读者提供一个强健的、跨越学科界限的工具箱,用于分析和理解自然界中普遍存在的自发秩序之美。