The freezing behavior of gold nanoclusters was studied by employing molecular dynamics simulations based on the semiempirical embedded-atom method. Investigations of the gold nanoclusters revealed that, just after freezing, ordered nanosurfaces with a fivefold symmetry were formed with interior atoms remaining in the disordered state. Further lowering of temperatures induced nanocrystallization...

As a test of the hypothesis that REM sleep deprivation reduces fear, the freezing behavior of 60 rats was measured under the conditions of the Bolles-Collier (1976) paradigm. These animals were first exposed to one of three treatments for 4 day s: a dry-environment control, a wetenvironment control, or a 4-day REM deprivation period. Next, the animals were fear conditioned in a square-box and t...

Climate change is likely to modify the freezing–thawing cycles in soils and surface waters of permafrost-affected subarctic regions. However, solution chemical composition during ice formation evolution remaining fluids remain very poorly known. Towards a better understanding dissolved (<0.45 µm) organic carbon, as well major trace element behavior permafrost peatland environments, here we p...

Objective(s): Post-traumatic stress disorder (PTSD), one of the most devastating kinds of anxiety disorders, is the consequence of a traumatic event followed by intense fear. In rats with contextual fear conditioning (CFC), a model of PTSD caused by CFC (electrical foot shock chamber), deep brain stimulation (DBS) alleviates CFC abnormalities.Materials and Methods: Forty Male Wistar rats (220–2...

Soil freezing characteristic curve (SFCC) defines the relationship between unfrozen water content and subzero temperature. The SFCC is widely applied to estimate soil properties. current study explored effects of initial content, dry density, type desalination on during a freezing-thawing process. It showed that had great impacts SFCC, while density an insignificant effect SFCC. Hysteresis beha...

This study investigated the partitioning behavior of dissolved organic matter (DOM) in liquid and ice phases, as well as the changes in the optical properties and chlorine reactivity of DOM during the freezing processes of water. DOM was rejected from the ice phase and accumulated in the remaining liquid phase during water freezing. Moreover, the decrease in freezing temperature, as well as the...

In fear conditioning, a rat is placed in a distinct environment and delivered footshock. The response to the footshock itself is called an activity burst and includes running, jumping, and vocalization. The fear conditioned to the distinct environment by the footshock elicits complete immobility termed freezing. Lesions of the ventral periaqueductal gray (vPAG) strongly attenuate freezing. Howe...

The odors of predators used in animal models provide, in addition to electric footshock, an important means to investigate the neurobiology of fear. Studies indicate that cat odor and trimethylthiazoline (TMT), a synthetic compound isolated from fox feces, are often presented to rodents to induce fear-related responses including freezing, avoidance, stress hormone and, in some tests, risk asses...