China
Africa
Explore chapters and articles related to this topic
The economics–ecology nexus
Published in Peter N. Nemetz, Unsustainable World, 2022
Feedback loops are critical contributors to nonlinear system dynamics, and they can be either negative or positive. An archetypal example of a negative feedback system is the homeostatic system which regulates body temperature. There is a natural tendency to return to the equilibrium temperature of 98.6degreesFahrenheit (°F; or 37degreesCelsius [°C]) after any deviation—as long as this deviation is not too large (i.e. the temperature does not fall outside the domain of attraction which brings it back to normality).
23Na
Published in Guillaume Madelin, X-Nuclei Magnetic Resonance Imaging, 2022
Kidney. The kidney is essential in regulating homeostatic functions in the body such as extracellular fluid volume, acid–base balance (pH), electrolyte concentrations, and blood pressure (via maintaining salt and water balance). This role depends tightly on the regulation of extracellular sodium in the kidney, which builds up a concentration gradient from the cortex to the medulla. Thus renal function is tightly dependent on this corticomedullary gradient and mapping this gradient with sodium MRI could help assess kidney impairments. 23Na MRI has therefore potential to become a non-invasive renal metabolic biomarker and could measure of tissue sodium storage for clinical studies [202, 203].
Glossary of scientific and technical terms in bioengineering and biological engineering
Published in Megh R. Goyal, Scientific and Technical Terms in Bioengineering and Biological Engineering, 2018
Hemostasis is a cessation of bleeding; Arrest of bleeding or of circulation. When equilibrium within the body is maintained, homeostasis is said to occur. The human body maintains a steady internal environment for the proper functioning of the body. Maintaining a constant internal environment requires the body to make many adjustments. Adjustments within the body are referred to as regulation of homeostasis. Homeostatic regulation is comprised of three parts: a receptor, a control center and an effector.
Biomimetic materials based on zwitterionic polymers toward human-friendly medical devices
Published in Science and Technology of Advanced Materials, 2022
Various biological responses and infections may impair medical devices used in vivo; this may reduce the effectiveness of treatment and increase infected tissue, which can endanger lives [21–24]. These results are based on a series of biological reactions that are strongly related to various biomolecules and cellular systems present in living systems. Figure 1 shows representative biological reactions at the surface of materials. When medical devices are used to treat patients, they invade the living body. Living organisms undergo a healing process to repair this invasion and maintain life [25]. A change in the equilibrium state (homeostasis) is known as a disease. Homeostasis is a dynamic state in which the coordination of biomolecules occurs in a time-dependent manner. If the material in contact with the dynamic state of the biological tissue is static or its properties are very different from those of the biological tissue, a new biological reaction occurs that eliminates the two without applying them to each other.
Implications of estrogen receptor alpha (ERa) with the intersection of organophosphate flame retardants and diet-induced obesity in adult mice
Published in Journal of Toxicology and Environmental Health, Part A, 2022
Gwyndolin M. Vail, Sabrina N. Walley, Ali Yasrebi, Angela Maeng, Thomas J. Degroat, Kristie M. Conde, Troy A. Roepke
This study represents new insight into the role of ERα in OPFR-initiated disruption of ingestive behaviors and energy homeostasis. Dysregulation of energy homeostasis might result in metabolic disorders such as obesity, diabetes, and metabolic syndrome. Therefore, it is important to understand the underlying toxicological mechanisms involved following OPFR exposure that may be pre-disposing human populations to such conditions. Future studies should use these data as a foundation with which to build upon by the addition of further mechanistic examinations of metabolism and energy expenditure. OPFR disruption of electrophysiological activity of NPY and POMC neurons has been previously demonstrated (Vail and Roepke 2020), and future use of selective ERα knockout in these neuronal populations might provide valuable insight into how OPFR exposure interacts with estrogenic regulation of neuronal homeostatic hubs.
Solar shading devices integrating smart materials: an overview of projects, prototypes and products for advanced façade design
Published in Architectural Science Review, 2019
Homeostatic Façade is an example of solar shading device incorporating SMP (Mossé, Gauthier, and Kofod 2007). The Homeostatic Façade has three interdependent components: the sensor, the logic unit and the actuator. This device fits into a double-skin façade and takes advantage of the flexibility and low power consumption of dielectric elastomers (DEs). The actuator acts like an artificial muscle, consisting of a DE wrapped over a flexible polymer core. Expansion and contraction of the elastomer cause a flexible core to bend (Konarzewska 2017). Since this device is integrated in a smart system, it is possible to have a complete control of daylight. No information on the durability of the device has been provided by the authors since the shading elements are continually subjected to the stress of contractions and de-contractions.