Brown University

About: Brown University is a education organization based out in Providence, Rhode Island, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 35778 authors who have published 90896 publications receiving 4471489 citations. The organization is also known as: brown.edu & Brown.

Nonreactive Dynamics in Solution: The Emerging Molecular View of Solvation Dynamics and Vibrational Relaxation

Abstract: Two of the more fundamental ways in which molecules change their behavior when they are dissolved are that they can begin to exchange energy with the surrounding liquid and they can induce their surroundings to rearrange so as to provide a significant stabilizing influence. The first of these is typified by the process of vibrational population relaxation of a vibrationally hot species. The second conceptcritical to solution chemistryis what is known as solvation. Both of these processes are sufficiently fundamental that one would really like to know, at the most mechanical and molecular level possible, just what events are required in order to make them happen. But how difficult is it going to be to extract such molecular detail from the complicated many-body dynamics? The most microscopic level of understanding one could ever hope to possess might seem far removed from the finely detailed dynamical information which is available routinely for individual isolated molecules and for molecule−molecule colli...

A new look at cerebrospinal fluid circulation

Abstract: According to the traditional understanding of cerebrospinal fluid (CSF) physiology, the majority of CSF is produced by the choroid plexus, circulates through the ventricles, the cisterns, and the subarachnoid space to be absorbed into the blood by the arachnoid villi. This review surveys key developments leading to the traditional concept. Challenging this concept are novel insights utilizing molecular and cellular biology as well as neuroimaging, which indicate that CSF physiology may be much more complex than previously believed. The CSF circulation comprises not only a directed flow of CSF, but in addition a pulsatile to and fro movement throughout the entire brain with local fluid exchange between blood, interstitial fluid, and CSF. Astrocytes, aquaporins, and other membrane transporters are key elements in brain water and CSF homeostasis. A continuous bidirectional fluid exchange at the blood brain barrier produces flow rates, which exceed the choroidal CSF production rate by far. The CSF circulation around blood vessels penetrating from the subarachnoid space into the Virchow Robin spaces provides both a drainage pathway for the clearance of waste molecules from the brain and a site for the interaction of the systemic immune system with that of the brain. Important physiological functions, for example the regeneration of the brain during sleep, may depend on CSF circulation.