reversible transition
Recently Published Documents


TOTAL DOCUMENTS

119
(FIVE YEARS 28)

H-INDEX

28
(FIVE YEARS 5)

2021 ◽  
Vol 19 ◽  
Author(s):  
Qianzi Yang ◽  
Fang Zhou ◽  
Ao Li ◽  
Hailong Dong

: General anesthesia has been successfully used in the clinic for over 170 years, but its mechanisms of effect remain unclear. Behaviorally, general anesthesia is similar to sleep in that it produces a reversible transition between wakefulness and the state of being unaware of one’s surroundings. A growing discussion has been imposed regarding the common circuits of sleep and general anesthesia, as an increasing number of sleep-arousal regulatory nuclei are reported to participate in the consciousness shift occurring during general anesthesia. Recently, with progress in research technology, both positive and negative evidence for overlapping neural circuits between sleep and general anesthesia have emerged. This article provides a review of the latest evidence on the neural substrates for sleep and general anesthesia regulation by comparing the roles of pivotal nuclei in sleep and anesthesia.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
An Liu ◽  
Hong Song ◽  
Puyou Jia ◽  
Ying Lin ◽  
Qingping Song ◽  
...  

Chitosan-based intelligent artificial systems have been of increasing interest for their biocompatibility, multifunctionality, biological activity, and low cost. Herein, we report the fabrication of supramolecular nanoparticles based on water-soluble chitosan (WCS) and 1,1 ′ ,1 ″ ,1 ″ ′ -(ethene-1,1,2,2-tetrayl)tetrakis(benzene-4,1-diyl) tetrakis(azanediyl)tetraacetic acid (TPE-(N-COOH)4), which is capable of reversible transition between polyion complexes (PICs) and hydrogen bonding complexes (HBCs) with tunable aggregation-induced emission driven by pH value. The PIC micelles could be formed via electrostatic interaction between ammonium cations and carboxylate anions under mild alkaline conditions. The formation of the micelles dramatically blocks the nonradiative pathway and enhances the fluorescence of TPE moieties, and the maximum fluorescence intensity was achieved near the isoelectric point due to the restriction of intramolecular motion. In addition, the fluorescence intensity and size of the PIC micelles exhibited a temperature response in the range from 20 to 80°C. Upon adjusting the solution pH to 2, the PIC micelles were reconstructed into hydrogen-bonding complexes while the hydrogen bonding interaction between the protonated carboxyl groups of TPE-(N-COOH)4 and chitosan. Moreover, the size of the micelles underwent a remarkable decrease, whereas the fluorescence emission was further enhanced by ~6.25-fold. The pH actuated micellar transition from PIC to HBC with tunable fluorescence performance is fully reversible. This study provides novel multifunctional materials that are of great importance for their potential application in the fields of optoelectronic devices and chemical and biomedical sensors.


2021 ◽  
Author(s):  
Austin Marchese ◽  
Bijan Mirabi ◽  
Colton Johnson ◽  
Mark Lautens

Abstract A widely appreciated principle is that all reactions are fundamentally reversible. Observing reversible transition metal-catalyzed reactions, particularly those that include the cleavage of C–C bonds, are more challenging. The development of the palladium- and nickel-catalyzed carboiodination reactions afforded access to the syn- and anti-diastereomers of the iodo-dihydroisoquinolone products. Using these substrates, an extensive study investigating the catalytic reversibility of the C–C bond formation using a different palladium catalyst was undertaken. A combination of experimental and computational studies led to the discovery of a variety of new methodologies and concepts key to understanding the process of reversible C–C bond formations.


Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 103
Author(s):  
Guolong Zhang ◽  
Guilin Yang ◽  
Yimin Deng ◽  
Tianjiang Zheng ◽  
Zaojun Fang ◽  
...  

The soft robots actuated by pressure, cables, thermal, electrosorption, combustion and smart materials are usually faced with the problems of poor portability, noise, weak load capacity, small deformation and high driving voltages. In this paper, a novel pneumatic generator for soft robots based on the gas-liquid reversible transition is proposed, which has the advantages of large output force, easy deformation, strong load capacity and high flexibility. The pressure of the pneumatic generator surges or drops flexibly through the reversible transformation between liquid and gas phase, making the soft actuator stretch or contract regularly, without external motors, compressors and pressure-regulating components. The gas-liquid reversible-transition actuation process is modeled to analyze its working mechanism and characteristics. The pressure during the pressurization stage increases linearly with a rate regulated by the heating power and gas volume. It decreases exponentially with the exponential term as a quadratic function of time at the fast depressurization stage, while with the exponential term as a linear function of time at the slow depressurization stage. The drop rate can be adjusted by changing the gas volume and cooling conditions. Furthermore, effectiveness has been verified through experiments of the prototype. The pressure reaches 25 bar with a rising rate of +3.935 bar/s when 5 mL weak electrolyte solution is heated at 800 W, and the maximum depressurization rate in air cooling is –3.796 bar/s. The soft finger actuated by the pneumatic generator can bend with an angular displacement of 67.5°. The proposed pneumatic generator shows great potential to be used for the structure, driving and sensing integration of artificial muscles.


Author(s):  
Iosif Grinvald ◽  
Rostislav Kapustin

The paper presents the IR-study of the fluid-like state generated at ambient conditions for methane halides (iodomethane, tetrachloromethane, tri-chloromethane, and dichloromethane). It was shown that at vapor compression-extension procedure realized in variable thickness spectral cell (VTOC), the dual phase state exhibiting both gas and liquid properties arises. A reversible transition from a gas-like to a liquid-like shape, independent on the thermodynamic characteristics of the studied methane halides, was revealed.


Sign in / Sign up

Export Citation Format

Share Document