This review paper attempts to approximate the concept of biological stress to the stress concept in Physics using the phenomenological view of physics to discuss the source of generator forces of biological stress sta...This review paper attempts to approximate the concept of biological stress to the stress concept in Physics using the phenomenological view of physics to discuss the source of generator forces of biological stress state. Based on the literature, parallels are drawn between the two concepts and a discussion on the steady state in open systems and homeostatic state in biological systems is developed. Using the concepts of thermodynamic entropy and informational entropy, and comparing stress in living systems and nonliving, we attempt to build a basis for a view of stress as a principle of nature linked to the adaptability property of matter, opposing entropy. It is known that the increasing number of microstates possible in a complex system increases the entropy. In that way, entropy is related to the amount of additional information needed to specify the exact physical state of a system, given its macroscopic specification. By controlling the metabolic processes (catabolism-anabolism) to decrease the entropy, stress reduces the number of possible states for which the living system could evolve, avoiding the loss of “life information”, preserving its characteristics and preventing its extinction. The loss of function of a species within an ecosystem or of cells within an organ can be showing that the limits of the stress principle were “transgressed”. That is, the intensity and/or duration of stress exceeded the capacity of living organism to process of information extracted from stressor and reprogram its physiological mechanisms, activating its adaptability process, while its internal balance is preserved.展开更多
On the basis of two-dimensional constitutive relationships of piezoelectric materials, the analytic solution for simply supported piezoelectric beams under uniform exterior pressure was derived. Furthermore the result...On the basis of two-dimensional constitutive relationships of piezoelectric materials, the analytic solution for simply supported piezoelectric beams under uniform exterior pressure was derived. Furthermore the results were also compared with the ones of FEM for piezoelectric materials. Thus the foundation for further research of piezoelectric materials distribution sensing mechanism and the validation of numerical methods such as FEM is provided.展开更多
文摘This review paper attempts to approximate the concept of biological stress to the stress concept in Physics using the phenomenological view of physics to discuss the source of generator forces of biological stress state. Based on the literature, parallels are drawn between the two concepts and a discussion on the steady state in open systems and homeostatic state in biological systems is developed. Using the concepts of thermodynamic entropy and informational entropy, and comparing stress in living systems and nonliving, we attempt to build a basis for a view of stress as a principle of nature linked to the adaptability property of matter, opposing entropy. It is known that the increasing number of microstates possible in a complex system increases the entropy. In that way, entropy is related to the amount of additional information needed to specify the exact physical state of a system, given its macroscopic specification. By controlling the metabolic processes (catabolism-anabolism) to decrease the entropy, stress reduces the number of possible states for which the living system could evolve, avoiding the loss of “life information”, preserving its characteristics and preventing its extinction. The loss of function of a species within an ecosystem or of cells within an organ can be showing that the limits of the stress principle were “transgressed”. That is, the intensity and/or duration of stress exceeded the capacity of living organism to process of information extracted from stressor and reprogram its physiological mechanisms, activating its adaptability process, while its internal balance is preserved.
文摘On the basis of two-dimensional constitutive relationships of piezoelectric materials, the analytic solution for simply supported piezoelectric beams under uniform exterior pressure was derived. Furthermore the results were also compared with the ones of FEM for piezoelectric materials. Thus the foundation for further research of piezoelectric materials distribution sensing mechanism and the validation of numerical methods such as FEM is provided.
